US20160126373A1

US20160126373A1 - Method for manufacturing solar cell module

Info

Publication number: US20160126373A1
Application number: US14/738,637
Authority: US
Inventors: Zhiqiang Zhao; Weihua Tan; Feiyun LI; Zhanfeng Jiang; Long He
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2014-10-31
Filing date: 2015-06-12
Publication date: 2016-05-05
Also published as: US20160126365A1; US10529868B2; US20160126363A1; US10381493B2; US20160126390A1; US20160126362A1; US20160126372A1; US20160126364A1; US20190051764A9; US20160126389A1; US20160126361A1; US10193003B2; US10069019B2; US20160126388A1; US20160126366A1

Abstract

A solar cell module, comprising an upper cover plate, a front adhesive layer, a cell, a back adhesive layer and a back plate superposed in sequence, a secondary grid line being disposed on the cell, a conductive wire comprising a metal wire being disposed between the front adhesive layer and a front surface of the cell, a welding layer disposed on a welding position where the conductive wire and the secondary grid line are welded, the welding layer being an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent.

Description

The present application claims priority to the following 41 Chinese applications, the entireties of all of which are hereby incorporated by reference.

1. Chinese Patent Application No. 201410608576.6, filed Oct. 31, 2014;
2. Chinese Patent Application No. 201410606607.4, filed Oct. 31, 2014;
3. Chinese Patent Application No. 201410606601.7, filed Oct. 31, 2014;
4. Chinese Patent Application No. 201410606675.0, filed Oct. 31, 2014;
5. Chinese Patent Application No. 201410608579.X, filed Oct. 31, 2014;
6. Chinese Patent Application No. 201410608577.0, filed Oct. 31, 2014;
7. Chinese Patent Application No. 201410608580.2, filed Oct. 31, 2014;
8. Chinese Patent Application No. 201410606700.5, filed Oct. 31, 2014;
9. Chinese Patent Application No. 201410608469.3, filed Oct. 31, 2014;
10. Chinese Patent Application No. 201510085666.6, filed Feb. 17, 2015;
11. Chinese Patent Application No. 201510217625.8, filed Apr. 3, 2015;
12. Chinese Patent Application No. 201510217609.9, filed Apr. 3, 2015;
13. Chinese Patent Application No. 201520276309.3, filed Apr. 3, 2015;
14. Chinese Patent Application No. 201510217687.9, filed Apr. 3, 2015;
15. Chinese Patent Application No. 201510219182.6, filed Apr. 3, 2015;
16. Chinese Patent Application No. 201510217617.3, filed Apr. 3, 2015;
17. Chinese Patent Application No. 201520278183.3, filed Apr. 3, 2015;
18. Chinese Patent Application No. 201510217573.4, filed Apr. 3, 2015;
19. Chinese Patent Application No. 201510219540.3, filed Apr. 3, 2015;
20. Chinese Patent Application No. 201510218489.4, filed Apr. 3, 2015;
21. Chinese Patent Application No. 201510218563.2, filed Apr. 3, 2015;
22. Chinese Patent Application No. 201510219565.3, filed Apr. 3, 2015;
23. Chinese Patent Application No. 201510219436.4, filed Apr. 3, 2015;
24. Chinese Patent Application No. 201510218635.3, filed Apr. 3, 2015;
25. Chinese Patent Application No. 201520277480.6, filed Apr. 3, 2015;
26. Chinese Patent Application No. 201510219366.2, filed Apr. 3, 2015;
27. Chinese Patent Application No. 201520278409.X, filed Apr. 3, 2015;
28. Chinese Patent Application No. 201510218697.4, filed Apr. 3, 2015;
29. Chinese Patent Application No. 201510219417.1, filed Apr. 3, 2015;
30. Chinese Patent Application No. 201510221302.6, filed Apr. 3, 2015;
31. Chinese Patent Application No. 201510219353.5, filed Apr. 3, 2015;
32. Chinese Patent Application No. 201520280778.2, filed Apr. 3, 2015;
33. Chinese Patent Application No. 201510219378.5, filed Apr. 3, 2015;
34. Chinese Patent Application No. 201520280868.1, filed Apr. 3, 2015;
35. Chinese Patent Application No. 201510218574.0, filed Apr. 3, 2015;
36. Chinese Patent Application No. 201510217616.9, filed Apr. 3, 2015;
37. Chinese Patent Application No. 201520278149.6, filed Apr. 3, 2015;
38. Chinese Patent Application No. 201510218562.8, filed Apr. 3, 2015;
39. Chinese Patent Application No. 201510218535.0, filed Apr. 3, 2015;
40. Chinese Patent Application No. 201510217551.8, filed Apr. 3, 2015; and
41. Chinese Patent Application No. 201520276534.7, filed Apr. 3, 2015.

The present application is relevant to the following 10 U.S. applications, filed concurrently with the present application, the entireties of which are hereby incorporated by reference.

U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-23), entitled “Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-24), entitled “Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-26), entitled “Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-28), entitled “Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-29), entitled “Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-32), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-33), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-34), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______;
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-35), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______; and
U.S. patent application Ser. No. ______ (Attorney Docket No. 14880-36), entitled “Solar Cell Unit, Solar Cell Array, Solar Cell Module And Manufacturing Method Thereof,” filed ______.

FIELD

The present disclosure relates to the field of solar cells, and more particularly, to solar cell modules and manufacturing methods thereof.

BACKGROUND

A solar cell module is one of the most important components of a solar power generation device. Sunlight irradiates onto a cell from its front surface and is converted to electricity within the cell. Primary grid lines and secondary grid lines are disposed on the front surface. The primary grid lines and the secondary grid lines cover part of the front surface of the cell, which blocks out part of the sunlight, and the part of sunlight irradiating onto the primary grid lines and the secondary grid lines cannot be converted into electric energy. Thus, the primary grid lines and the secondary grid lines need to be as fine as possible in order for the solar cell module to receive more sunlight. However, the primary grid lines and the secondary grid lines serve to conduct current, and in terms of resistivity, the finer the primary grid lines and the secondary grid lines are, the smaller the conductive cross section area thereof is, which causes greater loss of electricity due to increased resistivity. Therefore, the primary grid lines and the secondary grid lines must be designed to achieve a balance between light blocking and electric conduction, and to take the cost into consideration.
The traditional solar cell module mainly adopts the structure of three primary grid lines. For the cell with three primary grid lines, the welding of the primary grid lines usually adopts the contact welding process, like iron welding. Currently, the solar cell module tends to have a structure of multiple primary grid lines, so as to increase the distance between the secondary grid lines and the primary grid lines, and the resulting series resistance of the cell, so as to improve the power generation performance. However, as for the structure of multiple primary grid lines, the difficulty of welding the primary grid lines is increased due to many welding points and hard positioning.

SUMMARY

In prior art, the primary grid lines and the secondary grid lines of the solar cells are made of expensive silver paste, which results in complicated manufacturing process of the primary grid lines and the secondary grid lines and high cost. When the cells are connected into a module, the primary grid lines on the front surface of a cell are welded with back electrodes of another adjacent cell by a solder strip. Consequently, the welding of the primary grid lines is complicated, and the manufacturing cost of the cells is high.
In prior art, two primary grid lines are usually disposed on the front surface of the cell, and formed by applying silver paste to the front surface of the cell. The primary grid lines have a great width (for example, up to over 2 mm), which consumes a large amount of silver, and makes the cost high.
In prior art, a solar cell with three primary grid lines is provided, but still consumes a large amount of silver, and has a high cost. Moreover, three primary grid lines increase the shaded area, which lowers the photoelectric conversion efficiency.
In addition, the number of the primary grid lines is limited by the solder strip. The larger the number of the primary grid lines is, the finer a single primary grid line is, and hence the solder strip needs to be narrower. Therefore, it is more difficult to weld the primary grid lines with the solder strip and to produce the narrower solder strip, and thus the cost of the welding rises up.
Consequently, from the perspective of lowering the cost and reducing the shaded area, in prior art, the silver primary grid lines printed on the cell are replaced with metal wires, for example, copper wires. The copper wires are welded with the secondary grid lines to output the current. Since the silver primary grid lines are no longer used, the cost can be reduced considerably. The copper wire has a smaller diameter to reduce the shaded area, so the number of the copper wires can be raised up to 10. This kind of cell may be called a cell without primary grid lines, in which the metal wire replaces the silver primary grid lines and solder strips in the traditional solar cells.
In prior art, there is a technical solution that the electrical connection of the metal wire and the cells is formed by laminating a transparent film pasted with metal wires and the cells, i.e. multiple parallel metal wires being fixed on the transparent film by adhesion, then being stuck on the cell, and finally being laminated to contact with the secondary grid lines on the cell. In other words, the metal wires are in contact with the secondary grid lines by the laminating process, so as to output the current. However, in this technical solution, the transparent film weakens the absorption rate of light, and a plurality of parallel metal wires may be in bad connection with the cells, which may affect the electrical performance. Thus, the number of the metal wires needs to be increased. If the number of the metal wires is increased, the absorption rate of light from the front surface is affected, and the performance of the product is degraded. Consequently, the product in this technical solution is not promoted and commercialized. Moreover, as said above, the number of the parallel metal wires is limited by the distance between adjacent metal wires. Since the metal wires are pasted and fixed on the transparent film by a bonding layer, the bonding layer may melt or be softened in the laminating process, and thus the metal wires will drift to some extent.
In prior art, copper wires are disposed in the adhesive layer of the solar cell module to serve as the primary grid lines, and the primary grid lines and the cell are connected by laminating the module. However, since the melting point of the adhesive layers is lower than the temperature of laminating the module. In the laminating process, the metal wire disposed in the adhesive layers will drift, which lowers the photoelectric conversion efficiency of the solar cell module.
In prior art, multiple parallel metal wires form electrical connection with the cells by infrared radiation, but the process is difficult to realize, and the welding cost is high.
Thus, in the field of solar cells, the structure of the solar cell is not complicated, but each component is crucial. The production of the primary grid lines takes various aspects into consideration, such as shaded area, electric conductivity, equipment, process, cost, etc., and hence becomes a difficult and hot issue in the solar cell technology. In the market, a solar cell with two primary grid lines is replaced with a solar cell with three primary grid lines in 2007 through huge efforts of those skilled in the art. A few factories came up with a solar cell with four primary grid lines around 2014. The concept of multiple primary grid lines is put forward in the recent years, but still there is no relatively mature product.
The present disclosure seeks to solve at least one of the problems existing in the related art to at least some extent.
The present application provides a solar cell without primary grid lines, which needs neither expensive silver primary grid line nor sold strip disposed on the cells, and thus lowers the cost. The solar cell without primary grid lines can be commercialized for mass production, easy to manufacture with simple equipment, especially in low cost, and moreover have high photoelectric conversion efficiency.
Thus, the present application provides a solar cell module that is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.
The present application further provides a method for manufacturing the solar cell module.
The present application further provides a solar cell that is easy to manufacture in low cost, and improves the photoelectric conversion efficiency.
According to a first aspect of embodiments of the present application, a solar cell module includes an upper cover plate, a front adhesive layer, a cell, a back adhesive layer and a back plate superposed in sequence, a secondary grid line being disposed on the cell, a conductive wire constituted by a metal wire being disposed between the front adhesive layer and a front surface of the cell, a welding layer disposed on a welding position where the conductive wire and the secondary grid line are welded, the welding layer being an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent.
In the solar cell module according to embodiments of the present application, the welding layer is disposed at the position where the conductive wires and the secondary grid lines are welded, and is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent. Since the alloy layer contains Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, and the amount of Bi is 15 to 60 weight percent, the alloy layer has a relatively low melting point, and if it is used as the welding layer between the conductive wires and the secondary grid lines, the electric contact between the conductive wires and the secondary grid lines can be increased, to lower the contact resistance between the conductive wires and the secondary grid lines and to further improves the photoelectric conversion efficiency of the solar cell module. Furthermore, if the alloy layer is used as the welding layer, the welding temperature is lowered, and hence the difficulty of the process is decreased, which can further reduce the cost.
According to a second aspect of embodiments of the present application, a method for manufacturing the solar cell module includes: welding a conductive wire constituted by a metal wire with a secondary grid line of a cell via a welding layer disposed in a position where the conductive wire and the secondary grid line are welded, in which the welding layer is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, and an amount of Bi is 15 to 60 weight percent; superposing an upper cover plate, a front adhesive layer, the cell welded with the conductive wire, a back adhesive layer and a back plate in sequence, such that a front surface of the cell faces the front adhesive layer, a back surface thereof facing the back adhesive layer, and laminating them to obtain the solar cell module.
According to a third aspect of embodiments of the present application, a solar cell unit consists of a cell and a conductive wire. The cell includes a cell substrate and a secondary grid line disposed on a front surface of a cell substrate; the conductive wire is constituted by a metal wire and welded with the secondary grid line; a welding layer is disposed on a position where the conductive wire and the secondary grid line are welded; the welding layer is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, an amount of Bi being 15 to 60 weight percent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a solar cell array according to an embodiment of the present disclosure;

FIG. 2A is a longitudinal sectional view of a solar cell array according to an embodiment of the present disclosure;

FIG. 2B is a longitudinal sectional view of a solar cell array according to another embodiment of the present disclosure;

FIG. 3A is a transverse sectional view of a solar cell array according to embodiments of the present disclosure;

FIG. 3B is a transverse sectional view of a solar cell array according to another embodiment of the present disclosure;

FIG. 3C is a transverse sectional view of a solar cell array according to still another embodiment of the present disclosure;

FIG. 4A is a schematic diagram of a metal wire for forming a conductive wire according to embodiments of the present disclosure;

FIG. 4B is a schematic diagram of a metal wire for forming a conductive wire according to another embodiment of the present disclosure;

FIG. 5 is a plan view of a solar cell array according to another embodiment of the present disclosure;

FIG. 6 is a plan view of a solar cell array according to another embodiment of the present disclosure;

FIG. 7 is a schematic diagram of a metal wire extending reciprocally according to embodiments of the present disclosure;

FIG. 8 is a schematic diagram of two cells of a solar cell array according to embodiments of the present disclosure;

FIG. 9 is a sectional view of a solar cell array formed by connecting, by a metal wire, the two cells according to FIG. 8;

FIG. 10A is a schematic diagram of a solar cell module according to embodiments of the present disclosure;

FIG. 10B is a schematic diagram of a solar cell module according to another embodiment of the present disclosure;

FIG. 11A is a sectional view of part of the solar cell module according to FIG. 10A;

FIG. 11B is a sectional view of part of the solar cell module according to FIG. 10B;

FIG. 12 is a schematic diagram of a solar cell array according to another embodiment of the present disclosure;

FIG. 13 is a schematic diagram of a process of manufacturing a solar cell module according to an embodiment of the present disclosure;

FIG. 14 is another schematic diagram of a process of manufacturing a solar cell module according to an embodiment of the present disclosure;

FIG. 15 is a schematic diagram of a process of manufacturing a solar cell module according to another embodiment of the present disclosure;

FIG. 16 is another schematic diagram of a process of manufacturing a solar cell module according to another embodiment of the present disclosure.

FIG. 17A is a schematic diagram of a secondary grid line according to an embodiment of the present disclosure.

FIG. 17B is a schematic diagram of a secondary grid line according to another embodiment of the present disclosure.

FIG. 18 is a schematic diagram of a transparent film frame according to an embodiment of the present disclosure.

REFERENCE NUMERALS

- 100 cell module
- 10 upper cover plate
- 20 front adhesive layer
- 30 cell array
- 31 cell
- 31A first cell
- 31B second cell
- 311 cell substrate
- 312 secondary grid line
- 312A front secondary grid line
- 312B back secondary grid line
- 3121 edge secondary grid line
- 3122 middle secondary grid line
- 313 back electric field
- 314 back electrode
- 32 conductive wire
- 32A front conductive wire
- 32B back conductive wire
- 321 metal wire
- 322 connection material layer
- 33 short grid line
- 40 back adhesive layer
- 50 lower cover plate
- 60 U-shape frame
- 70 pressing plate
- 71 pressing block
- 80 coil

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail and examples of the embodiments will be illustrated in the drawings, where same or similar reference numerals are used to indicate same or similar members or members with same or similar functions. The embodiments described herein with reference to the drawings are explanatory, which are used to illustrate the present disclosure, but shall not be construed to limit the present disclosure.
Part of technical terms in the present disclosure will be elaborated herein for clarity and convenience of description.
Cell 31 includes a cell substrate 311, secondary grid lines 312 disposed on a front surface (the surface on which light is incident) of the cell substrate 311, a back electric field 313 disposed on a back surface of the cell substrate 311, and back electrodes 314 disposed on the back electric field 313. Thus, the secondary grid lines 312 can be called the secondary grid lines 312 of the cell 31, the back electric field 313 called the back electric field 313 of the cell 31, and the back electrodes 314 called the back electrodes 314 of the cell 31.
The cell substrate 311 can be an intermediate product obtained by subjecting, for example, a silicon chip to processes of felting, diffusing, edge etching and silicon nitride layer depositing. However, it shall be understood that the cell substrate 311 in the present disclosure is not limited to be formed by the silicon chip, but includes any other suitable solar cell substrate 311.
In other words, the cell 31 comprises a silicon chip, some processing layers on a surface of the silicon chip, secondary grid lines on a front surface, and a back electric field 313 and back electrodes 314 on a back surface, or includes other equivalent solar cells of other types without any front electrode.
Cell unit includes a cell 31 and conductive wires 32 constituted by a metal wire S.
A solar cell array 30 includes a plurality of cells 31 and conductive wires 32 which connect adjacent cells 31 and are constituted by the metal wire S. In other words, the solar cell array 30 is formed of a plurality of cells 31 connected by the conductive wires 32.
In the solar cell array 30, the metal wire S constitutes the conductive wires 32 of the cell unit, and extends between surfaces of the adjacent cells 31, which shall be understood in a broad sense that the metal wire S may extend between front surfaces of the adjacent cells 31, or may extend between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31. When the metal wire S extends between the front surface of the first cell 31 and the back surface of the second cell 31 adjacent to the first cell 31, the conductive wires 32 may include front conductive wires 32A extending on the front surface of the cell 31 and electrically connected with the secondary grid lines 312 of the cell 31, and back conductive wires 32B extending on the back surface of the cell 31 and electrically connected with the back electrodes 314 of the cell 31. Part of the metal wire S between the adjacent cells 31 can be called connection conductive wires.
In the present disclosure, the cell substrate 311, the cell 31, the cell unit, the cell array 30 and the solar cell module are only for the convenience of description, and shall not be construed to limit the present disclosure.
All the ranges disclosed in the present disclosure include endpoints, and can be individual or combined. It shall be understood that the endpoints and any value of the ranges are not limited to an accurate range or value, but also include values proximate the ranges or values.
In the present disclosure, orientation terms such as “upper” and “lower” usually refer to the orientation “upper” or “lower” as shown in the drawings under discussion, unless specified otherwise; “front surface” refers to a surface of the solar cell module facing the light when the module is in operation, i.e. a surface on which light is incident, while “back surface” refers to a surface of the solar cell module back to the light when the module is in operation.
In the following, a method for manufacturing a solar cell module according to the embodiments of the present disclosure will be described with respect to the drawings.
Specifically, the method according to the embodiments of the present disclosure includes: welding in high frequency a conductive wire 32 constituted by a metal wire with a cell 31; superposing an upper cover plate 10, a front adhesive layer 20, the cell 31, a back adhesive layer 40 and a back plate 50 in sequence, and laminating them to obtain the solar cell module.
In other words, in the process of laminating the solar cell module, the conductive wires 32 constituted by the metal wire are welded with the cell 31 in high frequency; then the upper cover plate 10, the front adhesive layer 20, the cell 31, the back adhesive layer 40 and the back plate 50 are superposed in sequence and laminated, so as to obtain the solar cell module 100.
In the following, the high-frequency welding method will be described with respect to the drawings.
Specifically, as shown in FIG. 13 and FIG. 14, an execution mode of high-frequency welding includes: arranging the conductive wires 32 on the cell 31 based on the requirements; placing the conductive wires 32 and the cell 31 between upper and lower pressing plates 70, in which a pressing block 71 is disposed on the upper pressing plate 70; surrounding the peripheries of the cell 31 by coils 80; generating high-frequency current in the coils 80 by a high-frequency power supply, so as to generate induced current in the cell 31 close to the coils 80 and the conductive wires 32, to heat the cell 31 and the conductive wires 32 by the induced current, and to weld the cell 31 and the conductive wires 32.
As shown in FIG. 15 and FIG. 16, an execution mode of high-frequency welding includes: placing the conductive wires 32 and the cell 31 between upper and lower pressing plates 70, in which a pressing block 71 is disposed on the upper pressing plate 70; disposing the coils 80 at one side of the cell 31; generating high-frequency current in the coils 80 by a high-frequency power supply, so as to generate induced current in the cell 31 close to the coils 80 and the conductive wires 32, to heat the cell 31 and the conductive wires 32 by the induced current, and to weld the cell 31 and the conductive wires 32.
In the first execution mode of high-frequency welding, the process of manufacturing the solar cell module 100 may include: superposing the upper cover plate 10, the front adhesive layer 20, the cell 31, the back adhesive layer 40 and the back plate 50 sequentially from up to down; arranging the conductive wires 32 on the cell 31 based on the requirements; placing the conductive wires 32 and the cell 31 between upper and lower pressing plates 70, in which a pressing block 71 is disposed on the upper pressing plate 70; surrounding the peripheries of the cell 31 by coils 80; generating high-frequency current in the coils 80 by a high-frequency power supply, so as to generate induced current in the cell 31 close to the coils 80 and the conductive wires 32, to heat the cell 31 and the conductive wires 32 by the induced current, and to weld the cell 31 and the conductive wires 32. Meanwhile, the induced current heats the cell 31, the adhesive layers (including the front adhesive layer 20 and the back adhesive layer 40), the cover plates (including the upper cover plate 10 and the back plate 50), and they are laminated by the pressing block 71, so as to obtain the solar cell module 100.
In the second execution mode of high-frequency welding, the process of manufacturing the solar cell module 100 may include: superposing the upper cover plate 10, the front adhesive layer 20, the cell 31, the back adhesive layer 40 and the back plate 50 sequentially from up to down; placing the conductive wires 32 and the cell 31 between upper and lower pressing plates 70, in which a pressing block 71 is disposed on the upper pressing plate 70; disposing the coils 80 at one side of the cell 31; generating high-frequency current in the coils 80 by a high-frequency power supply, so as to generate induced current in the cell 31 close to the coils 80 and the conductive wires 32, to heat the cell 31 and the conductive wires 32 by the induced current, and to weld the cell 31 and the conductive wires 32. Meanwhile, the induced current heats the cell 31, the adhesive layers (including the front adhesive layer 20 and the back adhesive layer 40), the cover plates (including the upper cover plate 10 and the back plate 50), and they are laminated by the pressing block 71, so as to obtain the solar cell module 100.
Consequently, the method for manufacturing the solar cell module according to the embodiments of the present disclosure adopts the high-frequency welding to weld the conductive wires and the cell, and assembles the cover plate, the front adhesive layer, the cell, the back adhesive layer and the back plates by laminating to obtain the solar cell module. The method can achieve the welding of the conductive wires and the cells, avoid insufficient welding, and prevent the conductive wires from drifting in the laminating process. The method is easy to implement in low cost, and the solar cell module obtained has high photoelectric conversion efficiency.
According to an embodiment of the present disclosure, the conductive wire and the cell are welded before or when they are laminated. Thus, the process of assembling the conductive wires 32 and the cell 31 is more flexible, and they are easier to manufacture.
In the present disclosure, there are at least two cells 31, and the conductive wire 32 extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31.
That's to say, in some specific embodiments of the present disclosure, there are multiple cells 31 to constitute the cell array 30, adjacent cells 31 connected by the conductive wires 32 that extend reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31. The conductive wires 32 and the cells 31 are connected by high-frequency welding.
Specifically, the solar cell array 30 according to the embodiments of the present disclosure includes a plurality of cells 31. The adjacent cells 31 are connected with a plurality of conductive wires 32 which are constituted by a metal wire S. The metal wire S is electrically connected with the cells 31 by high-frequency welding and extends reciprocally between the surfaces of the adjacent cells 31.
The cell unit is formed by the cell 31 and the conductive wires 32 constituted by the metal wire S which extends on the surface of the cell 31. In other words, the solar cell array 30 according to the embodiments of the present disclosure are formed with a plurality of cell units; the conductive wires 32 of the plurality of cells are formed by the metal wire S which extends reciprocally between the surfaces of the cells 31.
It shall be understood that the term “extending reciprocally” in this disclosure can be called “winding” which means that the metal wire S extends between the surfaces of the cells 31. For example, referring to FIG. 1, in some circumstances, the metal wire extends between the surfaces of the cells 31 in the same plane, such as either between the front surfaces or between the bottom surfaces of the cells, to form a serpentine pattern. In some other circumstances, the metal wire S extends between the surfaces of the cells 31 in multiple planes, such as between both the front surface of a cell and the bottom surface of an adjacent cell, to form a serpentine pattern. In yet other circumstances, the metal wire S extends between the surfaces of the cells 31 both in the same plane and in multiple planes, such as sometimes between either the front surfaces or the bottom surfaces of some adjacent cells, and at other times between both the front surface of a certain cell and the bottom surface of an adjacent cell, to form a serpentine pattern. The plurality of conductive wires equals two or more passes of the serpentine shaped pattern. Preferably, two or more passes of the serpentine shaped pattern on the same plane are substantially parallel to each other. More preferably, all the passes of the serpentine shaped pattern on the same plane are substantially parallel to each other.
In the present disclosure, it shall be understood in a broad sense that “the metal wire S extends reciprocally between surfaces of the cells 31. For example, the metal wire S may extend reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31; the metal wire S may extend from a surface of the first cell 31 through surfaces of a predetermined number of middle cells 31 to a surface of the last cell 31, and then extends back from the surface of the last cell 31 through the surfaces of a predetermined number of middle cells 31 to the surface of the first cell 31, extending reciprocally like this.
In addition, when the cells 31 are connected in parallel by the metal wire S, the metal wire S can extend on front surfaces of the cells 31, such that the metal wire S constitutes front conductive wires 32A. Alternatively, a first metal wire S extends reciprocally between the front surfaces of the cells 31, and a second metal wire S extends reciprocally between the back surfaces of the cells 31, such that the first metal wire S constitutes front conductive wires 32A, and the second metal wire S constitutes back conductive wires 32B.
When the cells 31 are connected in series by the metal wire S, the metal wire S can extend reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31, such that part of the metal wire S which extends on the front surface of the first cell 31 constitutes front conductive wires 32A, and part thereof which extends on the back surface of the second cell 31 constitutes back conductive wires 32B. In the present disclosure, unless specified otherwise, the conductive wires 32 can be understood as the front conductive wires 32A, the back conductive wires 32B, or the combination thereof.
The term “extending reciprocally” can be understood as that the metal wire S extends reciprocally once to form to two conductive wires 32 which are formed by winding a metal wire S. For example, two adjacent conductive wires form a U-shape structure or a V-shape structure, yet the present disclosure is not limited to the above.
In the solar cell array 30 according to the embodiments of the present disclosure, the conductive wires 32 of the plurality of cells 31 are constituted by the metal wire S which extends reciprocally; and the adjacent cells 31 are connected by the conductive wires 32. Hence, the conductive wires 32 of the cells are not necessarily made of expensive silver paste, and can be manufactured in a simple manner without using a solder strip to connect the cells. It is easy and convenient to connect the metal wire S with the secondary grid lines and the back electrodes, so that the cost of the cells is reduced considerably.
Moreover, since the conductive wires 32 are constituted by the metal wire S which extends reciprocally, the width of the conductive wires 32 (i.e. the width of projection of the metal wire on the cell) may be decreased, thereby decreasing the shaded area of the conductive wires 32. Further, the number of the conductive wires 32 can be adjusted easily, and thus the resistance of the conductive wires 32 is reduced, compared with the primary grid lines made of the silver paste, and the photoelectric conversion efficiency is improved. Since the metal wire S extends reciprocally to form the conductive wires, when the cell array 30 is used to manufacture the solar cell module 100, the metal wire S will not tend to shift, i.e. the metal wire is not easy to “drift”, which will not affect but further improve the photoelectric conversion efficiency.
Therefore, the solar cell array 30 according to the embodiments of the present disclosure has low cost and high photoelectric conversion efficiency.
Moreover, it shall be noted that in the present disclosure, the conductive wires 32 can be constituted by the metal wire S which is coated with the conductive adhesive and extends reciprocally between the surfaces of the adjacent cells, or can be arranged by multiple metal wires in parallel to and spaced apart from each other. It is understandable for those skilled in the art that in the technical solution a plurality of individual metal wires are spaced apart from each other to form the primary grid lines of the traditional structure, which will not be described in detail.
Preferably, there is a metal wire extending reciprocally between adjacent cells 31 in a row; and there is a metal wire extending reciprocally between cells 31 in adjacent rows. Thus, adjacent cells 31 can be connected by a single metal wire that extends reciprocally for several times, which is easier to manufacture in lower cost.
In some other specific embodiments of the present application, the conductive wires 32 are formed by a plurality of metal wires arranged parallel to and spaced from each other.
That's to say, in the present application, the metal wire S for constituting the conductive wires 32 can be a single one. The metal wire S extends reciprocally for several times to form the conductive wires 32. Or, there may be multiple metal wires S that are spaced apart from and in parallel to each other, so as to form the conductive wires 32.
Alternatively, as shown in FIG. 1, FIG. 2B, FIG. 3B, FIG. 4 to FIG. 11, the solar cell module 100 according to the embodiments of the present disclosure includes an upper cover plate 10, a front adhesive layer 20, a cell 31, a back adhesive layer 40 and a back plate 50 superposed in sequence.
The cell 31 has secondary grid lines. The conductive wires 32 constituted by the metal wire are disposed between the front adhesive layer 20 and the front surface of the cell 31 and welded with the secondary grid lines 312. The welding layer is disposed at a position where the conductive wires 32 and the secondary grid lines 312 are welded, and is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent.
In other words, the solar cell module 100 according to the embodiments of the present disclosure is mainly formed with an upper cover plate 10, a front adhesive layer 20, a cell 31, a back adhesive layer 40 and a back plate 50 superposed sequentially from up to down. The cell 31 mainly consists of a cell substrate 311 and secondary grid lines 312. In the present disclosure, the secondary grid lines 312 disposed on the front surface of the cell substrate 311 will be illustrated in detail.
The conductive wires 32 and the secondary grid lines 312 are connected by welding, and the welding layer is disposed at the welding position. The welding layer is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent.
The front adhesive layer 20 and the back adhesive layer 40 are adhesive layers commonly used in the art. Preferably, the front adhesive layer 20 and the back adhesive layer 40 are polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA). In the present disclosure, polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA) are conventional products in the art, or can be obtained in a method known to those skilled in the art.
In the embodiments of the present disclosure, the upper cover plate 10 and the back plate 50 can be selected and determined by conventional technical means in the art. Preferably, the upper cover plate 10 and the back plate 50 can be transparent plates respectively, for example, glass plates.
In some embodiments of the present disclosure, there are multiple cells 31 to constitute a cell array 30, adjacent cells 31 connected by the conductive wires 32; the metal wire S extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31.
Further, the adjacent cells 31 are connected by the conductive wires 32, and the metal wire S extends reciprocally between a front surface of the first cell 31 and a back surface of the second cell 31.
Further, the conductive wire 32 constituted by the metal wire S is disposed between the back adhesive layer 40 and the back surface of the second cell 31; the back surface of the second cell 31 is provided with a back electrode 314; the conductive wire 32 is welded with the back electrode 314 of the second cell 31; and a welding layer 322 is disposed at a position where the conductive wire 32 and the back electrode 314 are welded.
The welding layer 322 is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent. Further, based on the total weight of the alloy, there are 15 to 60 weight percent of Bi, 30 to 75 weight percent of Sn, 0 to 20 weight percent of Cu, 0 to 40 weight percent of In, 0 to 3 weight percent of Ag, 0 to 20 weight percent of Sb, 0 to 10 weight percent of Pb, and 0 to 20 weight percent of Zn in the alloy layer. Further, the alloy is at least one selected from 50% Sn-48% Bi-1.5% Ag-0.5% Cu, 58% Bi-42% Sn, and 65% Sn-20% Bi-10% Pb-5% Zn.
It shall be noted that in the present disclosure, the metal wire S refers to a metal wire for extending reciprocally on the cells 31 to form the conductive wires 32; and the conductive wires 32 can be a metal wire body 321, or can include a metal wire body 321 and a coating layer 322 outside the metal wire body 321, i.e. the metal wire S may be the metal wire body 321, or may consist of the metal wire body 321 and the coating layer 322 outside the metal wire body 321. In the embodiments of the present disclosure, unless specified otherwise, the metal wire represents the metal wire S which extends reciprocally on the cells 31 to form the conductive wires 32, in which the coating layer outside the metal wire body 321 can be an alloy layer like the welding layer 322.
In some embodiments, preferably, the metal wire body 321 is a copper wire or an aluminum wire. Preferably, the metal wire body is a copper wire, i.e. the metal wire S can be a copper wire, or can include a copper and a coating layer outside the copper wire. In other words, the conductive wire 32 can be a copper wire, or can include a copper and a coating layer outside the copper wire. Further preferably, the metal wire S is a copper wire, i.e. the conductive wire is a copper wire. Further preferably, the metal wire S has a circular cross section, such that more sunlight can reach the cell substrate to further improve the photoelectric conversion efficiency.
The welding layer 322 can be disposed at a position where the secondary grid line and/or the back electrode are welded with the conductive wire. The welding layer 322 can be disposed on the conductive wires 32. Preferably, the welding layer 322 is disposed on the conductive wires 32 where the conductive wires 32 are welded with the secondary grid lines and/or the back electrodes. Further preferably, the welding layer is disposed on the whole conductive wires and coats the conductive wires 32, as shown in FIG. 4. The conductive wires 32 are welded with the secondary grid lines on a front surface of a cell and the back electrodes on a back surface of another cell by the welding layer 322.
In the present disclosure, the metal wire S extends reciprocally between a front surface of the first cell 31 and a back surface of the second cell 31 to form the conductive wires 32. The conductive wires 32 are welded with the secondary grid lines on the front surface of the first cell and the back electrodes on the back surface of the second cell by the welding layer 322. Part of the conductive wires 32 welded with the secondary grid lines on the front surface of the first cell are called front conductive wires 32A, and part of the conductive wires 32 welded with the back electrodes on the back surface of the second cell are called back conductive wires 32B.
Other components of the solar cell module 100 according to the present disclosure are known in the art, which will be not described in detail herein.
Consequently, in the solar cell module 100 according to the embodiments of the present disclosure, the welding layers are disposed at the positions where the conductive wires 32 and the secondary grid lines 312 of a first cell 31 are welded, and the conductive wires 32 and the back electrodes 314 of a second cell 31 adjacent to the first cell are welded respectively, and the welding layers are the alloy according to the present disclosure, so as to improve performance of welding the conductive wires 32 with the secondary grid lines 312 and the back electrodes 314, and obtain relatively high photoelectric conversion efficiency of the solar cell module 100.
It shall be noted that in the present disclosure, the conductive wires 32 constituted by the metal wire and disposed between the front adhesive layer 20 and the front surface of the cell 31 are front conductive wires 32A; the conductive wires 32 constituted by the metal wire and disposed between the back adhesive layer 40 and the back surface of another adjacent cell 31 are back conductive wires 32B; the secondary grid lines 312 disposed on the upper surface of the cell substrate 311 are front secondary grid lines 312A; and the back surface of the cell substrate 311 can be provided with back electrodes 314, or can be back secondary grid lines 312B similar to the front secondary grid lines 312A in structure. In the present disclosure, unless specified otherwise, the secondary grid lines refer to the secondary grid lines 312A on the front surface of the cell.
The conductive wires 32 are welded with the secondary grid lines and/or the back electrodes by the welding layer 322, such that it is convenient to electrically connect the conductive wires 32 with the secondary grid lines 312, and to avoid drifting of the metal wire in the connection process so as to guarantee the photoelectric conversion efficiency. Of course, the electrical connection of the conductive wires 32 with the cell 31 can be conducted during or before the laminating process of the solar cell module, and preference is given to the latter.
In some other embodiments of the present disclosure, the secondary grid lines 312 are coated with a welding layer by which the conductive wires 32 are welded with the secondary grid lines 312.
That's to say, the conductive wires 32 and the secondary grid lines 312 can be welded by arranging the welding layer on the conductive wires 32 or on the secondary grid lines 312.
In the alloy according to the present disclosure, based on the total weight of the alloy, there are 15 to 60 weight percent of Bi, 30 to 75 weight percent of Sn, 0 to 20 weight percent of Cu, 0 to 40 weight percent of In, 0 to 3 weight percent of Ag, 0 to 20 weight percent of Sb, 0 to 10 weight percent of Pb, and 0 to 20 weight percent of Zn.
Specifically, in an embodiment of the present disclosure, the metal wire is coated with a welding layer. The ratio of the thickness of the welding layer and the diameter of the metal wire is (0.02-0.5):1.
That's to say, in the cell array 30, the ratio of the thickness of the welding layer and the diameter of the conductive wire 32 (including the front conductive wire 32A and back conductive wire 32B) is (0.02-0.5):1.
The welding layer may coat the metal wire completely or partially. When the welding layer coats the metal wire partially, the alloy layer is, preferably, formed at a position where the welding layer is welded with the secondary grid lines 312 of the cell 31. When the welding layer coats the metal wire completely, the welding layer can coat the periphery of the metal wire in a circular manner. The thickness of the welding layer can fall into a relatively wide range. Preferably, the welding layer has a thickness of 1 to 100 μm, more preferably, 1 to 30 μm. The cross section area of the conductive wire is preferably 0.01 to 0.5 mm.
The alloy for forming the welding layer in the present disclosure may have a melting point which can be 100 to 220° C. The alloy as the welding layer in the present disclosure contains Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent. The melting point is low, so as to enhance the reliability of welding the conductive wires and the secondary grid lines on the front surface of the cell 31 and the secondary grid lines on the back surface of the cell 31. The process is simple, so as to lower the welding cost. The solar cell module obtained has good and stable performance of connecting the conductive wires and the cell, such that the conductive wires will not be detached from the cell easily, and hence the solar cell module has high photoelectric conversion efficiency. Thus, the alloy for forming the welding layer can be called the alloy with the low melting point. Specifically, the alloy with the low melting point may be at least one of Sn—Bi alloy, Sn—Bi—Pb alloy, Sn—Bi—Ag alloy, Sn—Bi—Cu alloy and Sn—Bi—Zn alloy, i.e. the alloy contains Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn. Based on the total weight of the alloy, the amount of Bi is 15 to 60 weight percent. Further preferably, based on the total weight of the alloy, the amount of Bi is 15 to 60 weight percent, Sn 30 to 75 weight percent, Cu 0 to 20 weight percent, In 0 to 40 weight percent, Ag 0 to 3 weight percent, Sb 0 to 20 weight percent, Pb 0 to 10 weight percent, and Zn 0 to 20 weight percent. More preferably, the alloy is at least one selected from 50% Sn-48% Bi-1.5% Ag-0.5% Cu, 58% Bi-42% Sn and 65% Sn-20% Bi-10% Pb-5% Zn. Most preferably, the alloy with the low melting point is Bi—Sn—Pb alloy, for example, containing 40 weight percent of Sn, 55 weight percent of Bi, and 5 weight percent of Pb (i.e. Sn40%-Bi55%-Pb5%). The thickness of the welding layer can be 0.001 to 0.06 mm. The conductive wire 32 may have a cross section of 0.01 to 0.5 mm².
Preferably, in the present disclosure, the secondary grid line 312 has a width of 40 to 80 μm and a thickness of 5 to 20 μm; there are 50 to 120 secondary grid lines 312, a distance between adjacent secondary grid lines 312 ranging from 0.5 to 3 mm. Thus, the secondary grid lines 312 and the conductive wires 32 of this structure have better welding performance.
It can be understood that in the present disclosure, the cell 31 and the conductive wires 32 constitute a solar cell unit. That's to say, the solar cell unit in the present disclosure includes the above cell 31 and the conductive wires 32. The cell 31 includes a cell substrate 311 and secondary grid lines 312 disposed on the front surface of the cell substrate 311. The conductive wires 32 are constituted by the metal wire and welded with the secondary grid lines 312. The welding layer is disposed at a position where the conductive wires 32 and the secondary grid lines 312 are welded, and is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent. The connection relation of the cell 31 and the conductive wires 32 is described in detail in the above embodiments, so the structure of the solar cell unit will not be illustrated herein.
According to an embodiment of the present disclosure, there are multiple cells 31 to constitute a cell array 30, adjacent cells 31 connected by the conductive wires 32; the metal wire extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31.
Alternatively, as shown in FIG. 1 to FIG. 12, the solar cell module 100 according to the embodiments of the present disclosure includes an upper cover plate 10, a front adhesive layer 20, a cell array 30, a back adhesive layer 40 and a back plate 50.
The cell array 30 includes a plurality of cells 31. The adjacent cells 31 are connected with a plurality of conductive wires 32 constituted by a metal wire S which extends reciprocally between surfaces of adjacent cells. The metal wire includes a metal wire body 321 and a conductive adhesive 322 coating the metal wire body 321. The conductive wires 32 are in contact with the cells, the front adhesive layer 20 in direct contact with the conductive wires 32 and filling between adjacent conductive wires 32.
In other words, the solar cell module 100 according to the embodiments of the present disclosure includes the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 superposed sequentially along a direction from up to down. The cell array 30 includes a plurality of cells 31 and conductive wires 32 for connecting the plurality of cells 31. The conductive wires 32 are constituted by the metal wire S which extends reciprocally between surfaces of two adjacent cells 31. The metal wire includes the metal wire body 321 and the conductive adhesive 322 coating the metal wire body 321. Preferably, the conductive adhesive 322 coats the whole metal wire body 321 to form a metal wire S.
The conductive wires 32 are electrically connected with the cells 31, in which the front adhesive layer 20 on the cells 31 contacts with the conductive wires 32 directly and fills between the adjacent conductive wires 32, such that the front adhesive layer 20 can separate the conductive wires 32 from air and moisture from the outside world, so as to prevent the conductive wires 32 from oxidation and to guarantee the photoelectric conversion efficiency. In addition, in the process of laminating the cell module, the conductive adhesive has been cured and bound with the cell before the front adhesive layer melts, so as to guarantee the connection strength of the conductive wire and the cell, to prevent the conductive wire from drifting, and to improve the photoelectric conversion efficiency of the solar cell module.
It shall be noted that in the present disclosure, the metal wire S refers to a metal wire for extending reciprocally on the cells 31 to form the conductive wires 32; and the conductive wires 32 include a metal wire body 321 and a conductive adhesive 322 coating the metal wire body 321, i.e. the metal wire S consists of the metal wire body 321 and the conductive adhesive 322 coating the metal wire body 321. In the embodiments of the present disclosure, unless specified otherwise, the metal wire represents the metal wire S which extends reciprocally on the cells to form the conductive wires 32.
Thus, in the solar cell module 100 according to embodiments of the present disclosure, the conductive wires 32 constituted by the metal wire S which extends reciprocally replace traditional primary grid lines and solder strips, so as to reduce the cost. The metal wire S extends reciprocally to decrease the number of free ends of the metal wire S and to save the space for arranging the metal wire S, i.e. without being limited by the space. The number of the conductive wires 32 constituted by the metal wire which extends reciprocally may be increased considerably, which is easy to manufacture, and thus is suitable for mass production. The metal wire coated with the conductive adhesive on its surface serve as the metal wire S to constitute the conductive wires 32, such that the conductive wires 32 are connected with the cell via the conductive adhesive. In the laminating process, the conductive adhesive has been cured and bound with the cell before the front adhesive layer melts, so as to solve the problem that the metal wire drifts due to the melting of the front adhesive layer in the laminating process, and to obtain relatively high photoelectric conversion efficiency of the solar cell module. In addition, the front adhesive layer 20 contacts with the conductive wires 32 directly and fills between the adjacent conductive wires 32, which can effectively isolate the conductive wires from air and moisture to prevent the conductive wires 32 from oxidation to guarantee the photoelectric conversion efficiency.
The front adhesive layer 20 and the back adhesive layer 40 are adhesive layers commonly used in the art. Preferably, the front adhesive layer 20 and the back adhesive layer 40 are polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA) respectively. In the present disclosure, polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA) are conventional products in the art, or can be obtained in a method known to those skilled in the art.
In the embodiments of the present disclosure, the upper cover plate 10 and the back plate 50 can be selected and determined by conventional technical means in the art. Preferably, the upper cover plate 10 and the back plate 50 can be transparent plates respectively, for example, glass plates.
In the process of manufacturing the solar cell module 100, the conductive wires can be first bound, via the conductive adhesive, with the secondary grid lines 312 on the front surface of the first cell 31 and the back electrodes 314 on the back surface of the second cell 31, so as to form a cell array 30. Then, the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 are superposed and laminated to obtain the solar cell module 100.
Other components of the solar cell module 100 according to the present disclosure are known in the art, which will be not described in detail herein.
Specifically, the solar cell array 30 according to the embodiments of the present disclosure includes a plurality of cells 31. The adjacent cells 31 are connected by a plurality of conductive wires 32 which are constituted by a metal wire extending reciprocally between surfaces of the adjacent cells. The metal wire S includes a metal wire body 321 and a conductive adhesive 322 coating the metal wire body 321. The conductive wires 32 and the cell 31 form electric connection via the conductive adhesive. Or it can be said that the metal wire S extends reciprocally between the surfaces of the adjacent cells 31 to form the conductive wires 32.
According to yet another embodiment of the present disclosure, qs shown in FIG. 1, FIG. 2, FIG. 3C, FIG. 4B. FIG. 10B, FIG. 11B and FIG. 17, the solar cell module 100 according to the embodiments of the present disclosure includes an upper cover plate 10, a front adhesive layer 20, a cell 31, a back adhesive layer 40 and a back plate 50.
Specifically, the cell has secondary grid lines 312 (unless specified otherwise, the secondary grid lines 312 in the present disclosure refer to those on the front surface of the cell). The transparent film 60 is disposed between the front adhesive layer 20 and the cell 31. The conductive wire 32 is disposed on a surface of the transparent film 60 opposite the cell 31, and is inserted into the transparent film 60 and exposed therefrom. The conductive wire 32 is formed of a metal wire and connected with the secondary grid line 312. The transparent film 60 has a melting point higher than the melting point of the front adhesive layer 20 and the back adhesive layer 40.
In other words, the solar cell module 100 according to the embodiments of the present disclosure includes an upper cover plate 10, a front adhesive layer 20, a cell 31, a back adhesive layer 40 and a back plate 50 superposed sequentially from up to down. The cell 31 consists of a cell substrate 311 and the secondary grid lines 312 disposed on the cell substrate 311, and a transparent film 60 is disposed between the front adhesive layer 20 and the upper surface of the cell 31 (i.e. the shiny surface of the cell 31). The conductive wires 32 are disposed on the lower surface of the transparent film 60, in which the conductive wires 32 are inserted in the transparent film 60 and exposed therefrom. The conductive wires 32 are constituted by the metal wire S and connected with the secondary grid lines 312.
Further, in some embodiments of the present disclosure, the connection material layer 322 is disposed at a position where the secondary grid lines 312 on the front surface of the cell 31 are connected with the conductive wires 32. The conductive wires 32 are electrically connected with the secondary grid lines 312 of the cell 31 by the connection material layer 322 disposed on the secondary grid lines of the cell 31, in which the connection material layer 322 is a welding layer or a conductive adhesive. Preferably, the connection material layer 322 is a welding layer. The connection material layer is disposed at a position where the secondary grid lines of the cell 31 are connected with the conductive wires, so as to obtain better electric contact between the conductive wires and the secondary grid lines of the cell.
Specifically, the welding layer can be an alloy layer which contains Sn, Bi and at least one of Cu, In, Ag, Sb, Pb, and Zn, and has a melting point of 100 to 220° C.
Alternatively, the welding layer has a thickness of 1 to 20 μm, preferably 4 to 10 μm, a width of 10 to 300 μm, preferably 30 to 120 μm, and a length of 0.1 to 2 mm, preferably 0.25 to 1 mm.
Specifically, the alloy for forming the welding layer can be an alloy with a low melting point, for example a tin alloy. The tin alloy can be conventional in the art, for example, an alloy containing Sn, and at least one of Bi, Pb, Ag and Cu, specifically, SnBi, SnPb, SnBiCu, SnPbAg, etc, so as to avoid insufficient welding between the secondary grid lines 312 of the cell 31 and the conductive wires 32, and to obtain a relatively high photoelectric conversion efficiency of the solar cell module.
More specifically, when the connection layer is the welding layer, the alloy layer for forming the welding layer can cover the secondary grid lines 312 completely or partially. When the alloy layer for forming the welding layer covers the secondary grid lines 312 partially, the alloy layer is preferably formed at the position where the secondary grid lines and the conductive wires 32 are welded. The thickness, width and length of the welding layer can be selected in a broader range. Preferably, the welding layer has a thickness of 4 to 10 μm, a width of 30 to 120 μm, and a length of 0.25 to 1 mm. The alloy for forming the welding layer can be an alloy with low melting point in the art, and have a melting point of 100 to 220° C.
Preferably, the alloy with low melting point contains Sn and at least one of Bi, In, Ag, Sb, Pb and Zn. More preferably, the alloy with low melting point contains Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn. Specifically, the alloy with the low melting point may be at least one of Sn—Bi alloy, In—Sn alloy, Sn—Pb alloy, Sn—Bi—Pb alloy, Sn—Bi—Ag alloy, In—Sn—Cu alloy, Sn—Bi—Cu alloy and Sn—Bi—Zn alloy. Most preferably, the alloy with the low melting point is Bi—Sn—Pb alloy, for example, containing 40 weight percent of Sn, 55 weight percent of Bi, and 5 weight percent of Pb (i.e. Sn40%-Bi55%-Pb5%). The thickness of the welding layer can be 0.001 to 0.06 mm.
In some specific embodiments of the present disclosure, the alloy with low melting point contains Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn. Preferably, based on the total weight of the alloy, the amount of Bi is 15 to 60 weight percent, Sn 30 to 75 weight percent, Cu 0 to 20 weight percent, In 0 to 40 weight percent, Ag 0 to 3 weight percent, Sb 0 to 20 weight percent, Pb 0 to 10 weight percent, and Zn 0 to 20 weight percent. More preferably, the alloy is at least one selected from 50% Sn-48% Bi-1.5% Ag-0.5% Cu, 58% Bi-42% Sn and 65% Sn-20% Bi-10% Pb-5% Zn.
In the process of laminating the solar cell module 100, the transparent film 60 has a higher melting point than the front adhesive layer 20 and the back adhesive layer 40. In the laminating process, the front adhesive layer 20 and the back adhesive layer 40 melt, but the transparent film 60 will not melt, such that the metal wire S in the transparent film 60 is prevented from drifting, so as to obtain relatively photoelectric conversion efficiency of the solar cell module 100.
As shown in FIG. 4, the metal wire body 321 is coated with the connection material layer 322 to form the metal wire S, such as a conductive adhesive or a welding layer. The metal wire body 321 is welded with the secondary grid lines or the back electrodes via the connection material layer 322, so as to enhance the stability of connecting the metal wire with the secondary grid lines and/or the back electrodes, and to prevent the metal wire from drifting in the connection process which may affect the photoelectric conversion efficiency.
Consequently, in the solar cell module 100 according to the embodiments of the present disclosure, the transparent film 60 is disposed between the front adhesive layer 20 and the upper surface (i.e. the shiny surface) of the cell 31, and the conductive wire 32 is inserted in the transparent film 60 in advance in the manufacturing process, such that the metal wire will not drift because the front adhesive layer 20 and the back adhesive layer 40 melt in the laminating process, so as to guarantee the stability of connecting the conductive wire 32 and the secondary grid line 312 and the photoelectric conversion efficiency of the solar cell module 100.
Moreover, the metal wire body 321 is provided with the connection material layer connected with the secondary grid line to form the metal wire S, and the metal wire S constitutes the conductive wires, so as to improve the connection performance of the conductive wire and the secondary grid line, such that the solar cell module obtains relatively high photoelectric conversion efficiency.
The front adhesive layer 20 and the back adhesive layer 40 are adhesive layers commonly used in the art. Preferably, the front adhesive layer 20 and the back adhesive layer 40 are polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA). In the present disclosure, polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA) are conventional products in the art, or can be obtained in a method known to those skilled in the art.
In the embodiments of the present disclosure, the upper cover plate 10 and the back plate 50 can be selected and determined by conventional technical means in the art. Preferably, the upper cover plate 10 and the back plate 50 can be transparent plates respectively, for example, glass plates.
Other components of the solar cell module 100 according to the present disclosure are known in the art, which will be not described in detail herein.
It can be understood that in the present disclosure, the conductive wires 32 are inserted in the transparent film 60 disposed between the front adhesive layer and the upper surface of the cell 31, and located between the transparent film 60 and the upper surface of the cell 31. The conductive wires 32 in the embodiment can be understood as the front conductive wires 32A of the solar cell module 100, i.e. part of the conductive wires 32 connected with the secondary grid lines on the front surface of the cell 31 constituting the front conductive wires 32A.
In some specific embodiments of the present disclosure, there are multiple cells 31 to form the cell array 30, and adjacent cells 31 are connected by a plurality of conductive wires 322. The conductive wires 32 are constituted by the metal wire S which is electrically connected with the cell 31 and extends reciprocally between surfaces of the adjacent cells 31, so as to form the conductive wires.
When the cells 31 are connected in series by the metal wire S, the metal wire S extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31.
In the embodiment, the transparent film 60 is also disposed between the back adhesive layer 40 and the lower surface of the second cell 31 (i.e. the shady surface of the cell 31), and the conductive wires 32 are disposed on the surface of the transparent film 60 opposite the second cell 31, and are inserted into the transparent film 60 and exposed therefrom. The conductive wire 32 is formed of a metal wire and connected with the secondary grid line 312. The conductive wires 32 are connected with the back electrodes 314 of the second cell, and part of the conductive wires 32 connected with the back electrodes 314 of the second cell constitute the back conductive wires 32B of the second cell. Preferably, the connection material layer 322 is disposed at a position where the back electrodes 314 on the back surface of the second cell are connected with the conductive wires 32. The connection material layer 322 is a welding layer or a conductive adhesive. The conductive wires 32 are electrically connected with the back electrodes of the second cell by disposing the connection material layer 322 on the back electrodes of the second cell, in which the connection material layer 322 is a welding layer or a conductive adhesive. Preferably the connection material layer 322 is a welding layer. The welding layer is an alloy layer with low melting point, and the alloy layer is the above alloy layer with low melting point.
Specifically, in the solar cell module 100 of the present disclosure, the front conductive wires 32A are disposed on the front surface of the cell 31, and the back conductive wires 32B are disposed on the back surface of another adjacent cell 31. The front conductive wires 32A disposed on the front surface of the cell 31 are connected with the secondary grid lines 312 of the cell 31; and the back conductive wires 32B disposed on the back surface of the second cell 31 are connected with the back electrodes 314 of the cell 31.
Alternatively, the connection material layer 322 is arranged in a position where the metal wire body for constituting the front conductive wire 32A and the secondary grid line 312 are connected, or coats the metal wire body along an entire length of the metal wire body constituting the front conductive wire 32A; the connection material layer 322 is arranged in a position where the metal wire body for constituting the back conductive wire 332B and the back electrode 314 are connected, or coats the metal wire body along an entire length of the metal wire body constituting the back conductive wire 32B.
That's to say, in the solar cell module 100 of the present disclosure, the front conductive wires 32A are disposed on the front surface of the first cell 31, and the back conductive wires 32B are disposed on the back surface of the second cell 31. The front conductive wires 32A disposed on the front surface of the first cell 31 are provided with the connection material layer 322 by which the front conductive wires 32A are connected with the secondary grid lines 312 of the first cell 31; the back conductive wires 32B located on the back surface of the second cell 31 are also provided with the connection material layer 322, by which the back conductive wires 32B are connected with the back electrodes 314 of the second cell 31.
The connection material layer 322 may cover the whole metal wire body 321 completely, or may cover the position where the metal wire body 321 needs to be connected with the secondary grid lines 312 or the back electrodes 314.
It shall be noted that in the present disclosure, the metal wire S refers to a metal wire for extending reciprocally on the cells 31 to form the conductive wires 32, and consists of the metal wire body 321 and the connection material layer 322 coating the metal wire body 321. In other words, the conductive wires include the metal wire body 321 and the connection material layer 322 coating the metal wire body 321. In the embodiment of the present disclosure, unless specified otherwise, the metal wire refers to the metal wire S for extending reciprocally on the cells 31 to form the conductive wires 32.
Specifically, as for the back conductive wires 32B, the connection material layer 322 can be disposed at the position where the metal wire body 321 for constituting the back conductive wires 32B is connected with the back electrodes 314, or coat the metal wire body 321 along the entire length of the metal wire body 321 for constituting the back conductive wires 32B.
As for the front conductive wires 32A, the connection material layer 322 can be disposed at the position where the metal wire body 321 for constituting the front conductive wires 32A is connected with the secondary grid lines 312, or coat the metal wire body 321 along the entire length of the metal wire body 321 for constituting the front conductive wires 32A.
In the present disclosure, the conductive wires 32 (including the front conductive wires 32A and the back conductive wires 32B) can be inserted in the transparent film 60 by melting. The melting method includes: arranging the conductive wires 32 in the surface of the transparent film 60; heating the conductive wires 32 (e.g. electrical heating), such that the contact portion of the transparent film 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film 60 together.
Preferably, a first end of the conductive wire is arranged on the lower surface of the first transparent film 60, and a second end of the conductive wire is arranged on the upper surface of the second transparent film 60, and then the conductive wire is heated (e.g. electrical heating), such that the contact portion of the transparent film 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film 60 together. The first transparent film 60 whose lower surface is melted with the conductive wires faces a front surface of a first cell 31, such that the conductive wires 32 are connected with the secondary grid lines 312 on the front surface of the first cell; the second transparent film 60 whose upper surface is melted with the conductive wires faces a back surface of a second cell 31, such that the conductive wires 32 are connected with the back electrodes 314 on the back surface of the second cell; part of the conductive wires 32 welded with the secondary grid lines on the front surface of the first cell are called front conductive wires 32A, and part of the conductive wires 32 welded with the back electrodes on the back surface of the second cell are called back conductive wires 32B.
Preferably, as shown in FIG. 13, the connection material layer 322 is disposed at a position where the secondary grid lines 312 on the front surface of the first cell 31 are connected with the conductive wires 32. Another connection material layer 322 is disposed at a position where the back electrodes 314 on the back surface of the second cell 31 are connected with the conductive wires 32. The metal wire S extends reciprocally between a front surface of the first cell 31 and a back surface of the second cell 31 adjacent to the first cell 31 to form the conductive wires 32. The conductive wires 32 are electrically connected with the secondary grid lines 312 on the front surface of the first cell 31 by disposing the connection material layer 322, and electrically connected with the back electrodes 314 on the back surface of the second cell by the connection material layer 322.
In some specific embodiments of the present disclosure, the transparent film 60 is made of a transparent material with a melting point up to 160° C. When the transparent material for forming the transparent film has a melting point up to 160° C., the transparent film will not melt or be softened in the laminating process, so as to solve the problem that the metal wire tends to drift.
Preferably, the transparent film 60 is formed with at least one of polyethylene glycol terephthalate (PET), polybutylene terephthalate (PBT) and polyimide (PI).
In the present disclosure, the transparent film has a thickness of 50 to 200 μm, i.e. the transparent film 60 located on the front surface of the cell 31 and the transparent film 60 located on the back surface of the cell 31 have a thickness of 50 to 200 μm respectively. Further, in order to improve the photoelectric conversion efficiency of the solar cell module 100, the transparent film 60 has a light transmittance of no less than 90%.
In some embodiments of the present disclosure, the conductive wires 32 are not completely inserted in the transparent film 60, and part thereof project from the transparent film 60. The part of the conductive wires 32 projecting from the transparent film 60 at least contains an alloy layer of low melting point, such that the conductive wires 32 are in ohmic contact with the secondary grid lines 312 on the shiny surface of the cell 31 or the back electrodes 314 on the back surface of the cell 31. The conductive wires 32 refer to the front conductive wires 32A, the back conductive wires 32B, or the combination.
In some specific embodiments of the present application, the transparent film 60 is made of a transparent material with a melting point up to 160° C. In the embodiment, it can be guaranteed that the front adhesive layer 20 and the back adhesive layer 40 melt, but the transparent film 60 will not melt in the laminating process, such that the conductive wires 32 melted in the transparent film 60 will not drift.
According to another embodiment of the present disclosure, the connection material layer 322 is a welding layer or a conductive adhesive, and the welding layer is an alloy layer. In the following, the connection material layer 322 as the alloy layer will be illustrated in detail.
Specifically, in the present disclosure, the alloy contains Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn.
Preferably, based on the total weight of the alloy, there are 15 to 60 weight percent of Bi, 30 to 75 weight percent of Sn, 0 to 20 weight percent of Cu, 0 to 40 weight percent of In, 0 to 3 weight percent of Ag, 0 to 20 weight percent of Sb, 0 to 10 weight percent of Pb, and 0 to 20 weight percent of Zn in the alloy.
Further, the alloy can be at least one selected from 50% Sn-48% Bi-1.5% Ag-0.5% Cu, 58% Bi-42% Sn, and 65% Sn-20% Bi-10% Pb-5% Zn.
Alternatively, the connection material layer 322 has a thickness of 1 to 100 μm, and the metal wire body 321 has a cross section of 0.01 to 0.5 mm². Preferably, a ratio of a thickness of the connection material layer 322 and a diameter of the metal wire body 321 is (0.02-0.5):1.
Alternatively, the connection material layer 322 is disposed at the position where the metal wire body 321 is in contact with the secondary grid lines 312 and/or the back electrodes 314. The connection material layer 322 is a welding layer or a conductive adhesive. More preferably, the welding layers are disposed at the positions where the metal wire body 321 is in contact with the secondary grid lines 312 and the back electrodes 314 of the cell 31. The alloy for forming the welding layer can be an alloy with a low melting point, for example a tin alloy. The tin alloy can be conventional in the art, for example, an alloy containing Sn, and at least one of Bi, Pb, Ag and Cu, specifically, SnBi, SnPb, SnBiCu, SnPbAg, etc, so as to avoid insufficient welding between the metal wire body 321 and the secondary grid lines 312 and/or the back electrodes 314 of the cell 31, and to obtain a relatively high photoelectric conversion efficiency of the solar cell module.
In some specific embodiments of the present disclosure, there are multiple cells 31 to constitute the cell array 30, adjacent cells 31 connected by the metal wire S that extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31.
Specifically, the solar cell array 30 according to the embodiments of the present disclosure includes a plurality of cells 31. The adjacent cells 31 are connected with a plurality of conductive wires 32 which are constituted by a metal wire S. The metal wire S is electrically connected with the cells 31 and extends reciprocally between the surfaces of the adjacent cells 31.
The cell unit is formed by the cell 31 and the conductive wires 32 constituted by the metal wire S which extends on the surface of the cell 31. In other words, the solar cell array 30 according to the embodiments of the present disclosure are formed with a plurality of cell units; the conductive wires 32 of the plurality of cells are formed by the metal wire S which extends reciprocally between the surfaces of the cells 31.
It shall be understood that the term “extending reciprocally” in the disclosure can be called “winding” which refers to that the metal wire S extends between the surfaces of the cells 31 along a reciprocal route.
According to yet another embodiment, as shown in FIG. 1 to FIG. 18, the solar cell module 100 according to the embodiments of the present disclosure includes an upper cover plate 10, a front adhesive layer 20, a cell 31, a back adhesive layer 40 and a back plate 50.
Specifically, the cell array 30 includes a plurality of cells 31 and conductive wires 32 connected with secondary grid lines 312 on the cells 31, and two adjacent cells 31 are connected by the conductive wires 32; the transparent film frame 60 constituted by a longitudinal adhesive tape 61 and a transverse adhesive tape 62 intersected with each other, and the conductive wire 32 formed with a metal wire S and bonded with the longitudinal adhesive tape 61.
In other words, the solar cell module 100 according to the embodiments of the present disclosure includes an upper cover plate 10, a front adhesive layer 20, a transparent film frame 60, a cell array 30, a back adhesive layer 40 and a back plate 50 superposed sequentially from up to down. The cell 31 consists of a cell substrate 311 and the secondary grid lines 312 disposed on the cell substrate 311. The cell array 30 includes a plurality of cells 31 and the conductive wires 32 connected with secondary grid lines 312 on the cells 31, and two adjacent cells 31 are connected by the conductive wires 32. The transparent film frame 60 is constituted by a longitudinal adhesive tape 61 and a transverse adhesive tape 62 intersected with each other, and the conductive wires 32 are formed with a metal wire S and bonded with the longitudinal adhesive tape 61.
The transparent film frame 60 is constituted by the longitudinal adhesive tape 61 and the transverse adhesive tape 62 intersected with each other, instead of having a whole film structure. The transparent film frame 60 is provided with the longitudinal adhesive tape 61 and the transverse adhesive tape 62 only at a position where they are in need, and remains spare space in other portions, which reduces the light shading of the transparent film and facilitates light absorption of the solar cell, and hence improves the photoelectric conversion efficiency of the solar cell module. The metal wire S for constituting the conductive wires 32 is bounded with the longitudinal adhesive tape 61 of the transparent film frame 60, in which the binding can be implemented by melting. In other words, the metal wire S for constituting the conductive wires 32 is arranged on the transparent film frame 60, and heated, such that the portion where the transparent film frame 60 and the metal wire S are in contact will melt to connect the metal wire S with the transparent film frame 60, so as to fix the metal wire S on the transparent film frame 60. Hence, the metal wire S will not drift in the laminating process, which guarantees the stability of connecting the conductive wire 32 and the secondary grid line 312.
Thus, in the solar cell module 100 according to the embodiments of the present disclosure, the conductive wires 32 constituted by the metal wire S are bound with the longitudinal adhesive tape 61 of the transparent film frame 60, and then connected with the secondary grid lines 312 of the cell 31, so as to prevent the metal wire from drifting, to guarantee the stability of connecting the conductive wires 32 and the secondary grid lines 312, to reduce the shaded area of the transparent film frame 60, and to guarantee the photoelectric conversion efficiency of the solar cell module 100.
The front adhesive layer 20 and the back adhesive layer 40 are adhesive layers commonly used in the art. Preferably, the front adhesive layer 20 and the back adhesive layer 40 are polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA). In the present disclosure, polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA) are conventional products in the art, or can be obtained in a method known to those skilled in the art.
In the embodiments of the present disclosure, the upper cover plate 10 and the back plate 50 can be selected and determined by conventional technical means in the art. Preferably, the upper cover plate 10 and the back plate 50 can be transparent plates respectively, for example, glass plates.
Other components of the solar cell module 100 according to the present disclosure are known in the art, which will be not described in detail herein.
According to an embodiment of the present disclosure, the transverse adhesive tape 62 and the longitudinal adhesive tape 61 are welded or integrated by the adhesive or heating at a position where they are intersected.
That's to say, the transparent film frame 60 can have a film structure integrally formed, or can be formed by binding or welding the transverse adhesive tape 62 and the longitudinal adhesive tape 61 at the position where they are intersected. Thus, the transparent film frame 60 of this structure is easy to manufacture in low cost.
It shall be noted that in the present disclosure, the metal wire S refers to a metal wire for extending reciprocally on the cells 31 to form the conductive wires 32; and the conductive wires 32 may include a metal wire body 321 and a connection material layer 322 coating the metal wire body 321, i.e. the metal wire S can consist of the metal wire body 321 and the connection material layer 322 coating the metal wire body 321. In the embodiment of the present disclosure, unless specified otherwise, the metal wire refers to the metal wire S for extending reciprocally on the cells 31 to form the conductive wires 32.
In some embodiments, preferably, the metal wire body 321 is a copper wire, i.e. the metal wire S can be a copper wire, too. In other words, the metal wire does not include the coating layer, but the present disclosure does not limited thereto. For example, the metal wire body 321 can be an aluminum wire. In the present disclosure, preferably, the metal wire body 321 has a circular cross section, such that more sunlight can reach the cell substrate to further improve the photoelectric conversion efficiency.
The metal wire body 321 is coated with the connection material layer 322, such that it is convenient to electrically connect the metal with the secondary grid lines and/or the back electrodes, and to avoid drifting of the metal wire in the connection process so as to guarantee the photoelectric conversion efficiency. Of course, the electrical connection of the metal with the cell substrate can be conducted during or before the laminating process of the solar cell module, and preference is given to the latter.
In some other specific embodiments of the present disclosure, the metal wire body 321 is coated with a welding layer, and a ratio of a thickness of the welding layer and a diameter of the metal wire is (0.02-0.5):1.
That's to say, in the present disclosure, the connection material layer 322 is a welding layer, and a ratio of a thickness of the welding layer and a diameter of the metal wire falls into the range of (0.02-0.5):1.
Specifically, the welding layer contains Sn, and at least one of Bi, In, Ag, Sb, Pb and Zn. Alternatively, the welding layer contains Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn.
As shown in FIG. 13, in the present disclosure, the transparent film frame 60 is constituted by the longitudinal adhesive tape 61 and the transverse adhesive tape 62 intersected with each other. Multiple longitudinal adhesive tapes 61 can be arranged in parallel; multiple transverse adhesive tapes 62 can be also arranged in parallel; and the longitudinal adhesive tape 61 is perpendicular to the transverse adhesive tape 62.
In some specific embodiments of the present disclosure, the metal wire body 321 has a diameter of 0.05 to 0.5 mm. Preferably, the metal wire body 321 has a diameter of 0.15 to 0.25 mm. Preferably, the transverse adhesive tape 62 has a width of 0.1 to 5 mm. Further, the transverse adhesive tape 62 has a width of 0.5 to 2 mm.
In some examples, there are 1 to 10 transverse adhesive tapes 62. Preferably, there are 2 to 4 transverse adhesive tapes 62. In some examples, the transverse adhesive tape 62 has a thickness of 0.05 to 0.5 mm. Preferably, the transverse adhesive tape has a thickness of 0.1 to 0.2 mm.
Correspondingly, the longitudinal adhesive tape 61 has a width of 0.5 to 5 mm. Preferably, the longitudinal adhesive tape 61 has a width of 1 to 3 mm. There are 2 to 10 longitudinal adhesive tapes 61, preferably 2 to 4 longitudinal adhesive tapes 61. In some specific embodiments of the present disclosure, the longitudinal adhesive tape 61 has a thickness of 0.05 to 0.5 mm. Preferably, the longitudinal adhesive tape 61 has a thickness of 0.1 to 0.2 mm.
Thus, the metal wire body 321 of this structure can coordinate with the longitudinal adhesive tapes 61 and the secondary grid lines 312 on the cell 31; the transverse adhesive tapes 62 can fix the longitudinal adhesive tapes 61 better to guarantee the stability of the whole structure of the transparent film frame 60.
In some specific embodiments of the present disclosure, the solar cell array 30 includes multiple cells 31, adjacent cells 31 connected by the plurality of conductive wires 32. The conductive wires 32 are constituted by the metal wire S that is electrically connected with the cell 31, and extends reciprocally between the surfaces of the adjacent cells 31.
Specifically, there are multiple cells 31 to form the cell array 30. The adjacent cells 31 are connected with the metal wire S. The metal wire S is electrically connected with the cells 31 and extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31.
Preferably, there are multiple cells 31 to form the cell array 30. The adjacent cells 31 are connected with the metal wire S. The metal wire S is electrically connected with the cells 31 and extends reciprocally between a front surface of the first cell 31 and a back surface of the second cell 31 adjacent to the first cell 31, to connect the adjacent cells in series.
In the embodiment, the transparent film frame 60 is disposed between the front adhesive layer 20 and the upper surface of the first cell 31 (i.e. the shiny surface of the first cell 31), and the conductive wires 32 are disposed between the transparent film frame 60 and the upper surface of the first cell 31. The conductive wires 32 are constituted by the metal wire S, bound with the transparent film frame 60 and exposed therefrom, and are electrically with the secondary grid line 312 on the front surface of the first cell 31. In the embodiment, the conductive wires 32 are in contact with the back electrodes of the back surface of the second cell 31 to form electric connection.
In some other embodiments of the present disclosure, the transparent film frame 60 is disposed between the front adhesive layer 20 and the upper surface of the first cell 31 (i.e. the shiny surface of the first cell 31), and the conductive wires 32 are disposed between the transparent film frame 60 and the upper surface of the first cell 31. The conductive wires 32 are constituted by the metal wire S, bound with the transparent film frame 60 and exposed therefrom, and are electrically with the secondary grid line 312 on the front surface of the first cell 31. Further, the transparent film frame 60 is also disposed between the back adhesive layer 40 and the lower surface of the second cell 31 (i.e. the shady surface of the second cell 31), and the conductive wires 32 are disposed on the surface of the transparent film frame 60 opposite the second cell 31, and are inserted into the transparent film frame 60 and exposed therefrom. The conductive wire 32 is formed of a metal wire and connected with the secondary grid line 312. The conductive wires 32 are constituted by the metal wire S, bound with the transparent film frame 60 and exposed therefrom, and are in contact with the back electrodes 314 of the back surface of the second cell 31 to form electric connection.
Specifically, in the solar cell module 100 of the present disclosure, the front conductive wires 32A are disposed on the front surface of the cell 31, and the back conductive wires 32B are disposed on the back surface of another adjacent cell 31. The front conductive wires 32A disposed on the front surface of the cell 31 are connected with the secondary grid lines 312 of the cell 31; and the back conductive wires 32B disposed on the back surface of the second cell 31 are connected with the back electrodes 314 of the cell 31.
In the present disclosure, the conductive wires 32 (including the front conductive wires 32A and the back conductive wires 32B) can be inserted in the transparent film frame 60 by melting. The melting method includes: arranging the conductive wires 32 in the surface of the transparent film frame 60; heating the conductive wires 32 (e.g. electrical heating), such that the contact portion of the transparent film frame 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film frame 60 together.
Preferably, a first end of the conductive wire is arranged on the lower surface of the first transparent film frame 60, and a second end of the conductive wire is arranged on the upper surface of the second transparent film frame 60, and then the conductive wire is heated (e.g. electrical heating), such that the contact portion of the transparent film frame 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film frame 60 together. The first transparent film frame 60 whose lower surface is melted with the conductive wires faces a front surface of a first cell 31, such that the conductive wires 32 are connected with the secondary grid lines 312 on the front surface of the first cell; the second transparent film frame 60 whose upper surface is melted with the conductive wires faces a back surface of a second cell 31, such that the conductive wires 32 are connected with the back electrodes 314 on the back surface of the second cell; part of the conductive wires 32 welded with the secondary grid lines on the front surface of the first cell are called front conductive wires 32A, and part of the conductive wires 32 welded with the back electrodes on the back surface of the second cell are called back conductive wires 32B.
Alternatively, as shown in FIG. 1 to FIG. 18, the solar cell array 30 according to the embodiments of the present disclosure comprises a plurality of cells 31 and conductive wires 32; the conductive wires 32 are connected with front secondary grid lines 312 of the cell 31; and a connection material layer 3121 is disposed at a position where the secondary grid lines 312 are connected with the conductive wires 32.
In other words, the solar cell array 30 of the present disclosure consists of at least two cells 31, and the adjacent cells 31 are connected by a plurality of conductive wires 32. The cell 31 includes a cell substrate 311 and secondary grid lines 312 disposed on the cell substrate 311. The conductive wires 32 and the secondary grid lines 312 are connected to realize connection of two adjacent cells 31. The connection material layer 3121 is disposed at a position where the secondary grid lines 312 need to be connected with the conductive wires 32, so as to connect the secondary grid lines 312 with the conductive wires 32 (as shown in FIG. 13).
Thus, in the solar cell array 30 according to embodiments of the present disclosure, the connection material layer 3121 is disposed on the secondary grid lines 312 for connection with the conductive wires 32, so as to improve the connection performance of the conductive wires 32 and the secondary grid lines 312, to prevent the conductive wires 32 and the secondary grid lines 312 from drifting, and to render the solar cell module relatively high photoelectric conversion efficiency.
In some specific embodiments of the present disclosure, the connection material layer can be a welding layer or a conductive adhesive. In other words, in the present disclosure, the connection material layer 3121 on the secondary grid lines 312 can be a welding layer or a conductive adhesive.
Specifically, the welding layer is an alloy layer. The alloy layer contains Sn, Bi, and at least one of Cu, In, Ag, Sb, Pb and Zn. The alloy layer has a melting point of 100 to 220° C.
Alternatively, the welding layer has a thickness of 1 to 20 μm, preferably 4 to 10 μm. The welding layer has a width of 10 to 300 μm, preferably 30 to 120 μm. Further, the welding layer has a length of 0.1 to 2 mm, preferably 0.25 to 1 mm.
That's to say, the welding layer may be a metal with a lower melting point or an alloy, for example a tin alloy. The tin alloy can be a conventional tin alloy, for example, containing Sn, and at least one of Bi, Pb, Ag and Cu, more specifically, i.e. SnBi, SnPb, SnBiCu, SnPbAg, etc, so as to avoid insufficient soldering between the secondary grid lines 312 of the cell and the conductive wires 32, and to render the solar cell module higher photoelectric conversion efficiency.
More specifically, the alloy layer with a low melting point may cover the secondary grid lines 312 completely or partially. When the alloy layer covers the secondary grid lines 312 partially, the alloy layer is, preferably, formed at a position where it is welded with the conductive wires 32. The thickness, width and length of the alloy layer can be determined in a relatively wide range. Preferably, the alloy layer has a thickness of 4 to 10 μm, a width of 30 to 120 μm, and a length of 0.25 to 1 mm. The alloy for forming the alloy layer with a low melting point may be a conventional alloy with a low melting point which can be 100 to 200° C.
Preferably, the alloy with the low melting point contains Sn, and at least one of Bi, In, Ag, Sb, Pb and Zn, more preferably, containing Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn. Specifically, the alloy may be at least one of Sn—Bi alloy, In—Sn alloy, Sn—Pb alloy, Sn—Bi—Pb alloy, Sn—Bi—Ag alloy, In—Sn—Cu alloy, Sn—Bi—Cu alloy and Sn—Bi—Zn alloy. Most preferably, the alloy is Bi—Sn—Pb alloy, for example, containing 40 weight percent of Sn, 55 weight percent of Bi, and 5 weight percent of Pb (i.e. Sn40%-Bi55%-Pb5%). The thickness of the alloy layer with the low melting point can be 0.001 to 0.06 mm. The conductive wire 32 may have a cross section of 0.01 to 0.5 mm². The metal wire can be conventional in the art, for example, a copper wire.
In some specific embodiments of the present disclosure, based on the total weight of the alloy, there are 15 to 60 weight percent of Bi, 30 to 75 weight percent of Sn, 0 to 20 weight percent of Cu, 0 to 40 weight percent of In, 0 to 3 weight percent of Ag, 0 to 20 weight percent of Sb, 0 to 10 weight percent of Pb, and 0 to 20 weight percent of Zn in the alloy. Preferably, the alloy is at least one selected from 50% Sn-48% Bi-1.5% Ag-0.5% Cu, 58% Bi-42% Sn, and 65% Sn-20% Bi-10% Pb-5% Zn.
According to an embodiment of the present disclosure, the adjacent cells 31 are connected by a metal wire S that extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31 to form a plurality of conductive wires 32; the conductive wires 32 are connected with the secondary grid lines 312 on the front surface of the cell 31, a connection material layer 3121 being disposed at a position where the secondary grid lines on the front surface of the cell are connected with the conductive wires.
That's to say, in the present disclosure, two adjacent cells 31 are connected with the conductive wires 32, and the metal wire S extends reciprocally between the surfaces of the two adjacent cells. The secondary grid lines 312 of the cell 31 are provided with the connection material layer, so the conductive wires 32 are connected with the secondary grid lines 312 of the cell via the connection material layer 3121.
In the solar cell array according to the embodiments of the present application, since the conductive wires are constituted by the metal wire which extends reciprocally, the structure of the conductive wires that are arranged in a winding way between the adjacent cells 31 to extend reciprocally is a folded shape, which is easy to manufacture in low cost, and can improve the photoelectric conversion efficiency of the solar cell array. The conductive wires 32 are welded with the secondary grid lines 312, and the conductive wires 32 in the solar cell module will not drift and be insufficiently welded, so as to obtain relatively high photoelectric conversion efficiency.
Therefore, the solar cell array 30 according to the embodiments of the present application has low cost and high photoelectric conversion efficiency.
In the following, the solar cell array 30 according to specific embodiments of the present disclosure will be described with reference to the drawings.
The solar cell array 30 according to a specific embodiment of the present disclosure is illustrated with reference to FIG. 1 to FIG. 3.
In the embodiment shown in FIG. 1 to FIG. 3, two cells 31 in the solar cell array 30 are shown. In other words, it shows two cells 31 connected with each other via the conductive wires 32 constituted by the metal wire S.
It can be understood that the cell 31 comprises a cell substrate 311, secondary grid lines 312 (i.e. front secondary grid lines 312A) disposed on a front surface of the cell substrate 311, a back electric field 313 disposed on a back surface of the cell substrate 311, and back electrodes 314 disposed on the back electric field 313. In the present disclosure, it shall be understood that the back electrodes 314 may be back electrodes of a traditional cell, for example, printed by the silver paste, or may be back secondary grid lines 312B similar to the secondary grid lines on the front surface of the cell substrate, or may be multiple discrete welding portions, unless specified otherwise. The secondary grid lines refer to the secondary grid lines 312 on the front surface of the cell substrate 311, unless specified otherwise.
As shown in FIG. 1 to FIG. 3, the solar cell array in the embodiment includes two cells 31A, 31B (called a first cell 31A and a second cell 31B respectively for convenience of description). The metal wire S extends reciprocally between the front surface of the first cell 31A (a shiny surface, i.e. an upper surface in FIG. 2) and the back surface of the second cell 31B, such that the metal wire S constitutes front conductive wires of the first cell 31A and back conductive wires of the second cell 31B. The metal wire S is electrically connected with the secondary grid lines of the first cell 31A by high-frequency welding, and electrically connected with the back electrodes of the second cell 31B by high-frequency welding.
In an embodiment of the present application, back electrodes 314 are disposed on the back surface of the cell substrate 311, and the metal wire is welded with the back electrodes 314.
That's to say, in the embodiment, front secondary grid lines 312A are disposed on the front surface of the cell substrate 311, and back electrodes 314 are disposed on the back surface of the cell substrate 311. When located on the front surface of the cell substrate 311, the conductive wires 32 are welded with front secondary grid lines 312A; when located on the back surface of the cell substrate 311, the conductive wires 32 are welded with the back electrodes 314 on the back surface of the cell substrate 311.
In some embodiments, the metal wire extends reciprocally between the first cell 31A and the second cell 31B for 10 to 60 times to form 20 to 120 conductive wires. Preferably, as shown in FIG. 1, the metal wire extends reciprocally for 12 times to form 24 conductive wires 32, and there is only one metal wire. In other words, a single metal wire extends reciprocally for 12 times to form 24 conductive wires, and the distance of the adjacent conductive wires can range from 2.5 mm to 15 mm. In this embodiment, the number of the conductive wires is increased, compared with the traditional cell, such that the distance between the secondary grid lines and the conductive wires which the current runs through is decreased, so as to reduce the resistance and improve the photoelectric conversion efficiency. In the embodiment shown in FIG. 1, the adjacent conductive wires form a U-shape structure, for convenience of winding the metal wire. Alternatively, the present disclosure is not limited to the above. For example, the adjacent conductive wires can form a V-shape structure.
It shall be noted that in the present disclosure, the metal wire S refers to a metal wire for extending reciprocally on the cells 31 to form the conductive wires 32; and the conductive wires 32 may include a metal wire body 321 and a connection material layer 322 coating the metal wire body 321, i.e. the metal wire S can consist of the metal wire body 321 and the connection material layer 322 coating the metal wire body 321. In the embodiment of the present disclosure, unless specified otherwise, the metal wire refers to the metal wire S for extending reciprocally on the cells 31 to form the conductive wires 32.
In some embodiments, preferably, the metal wire body 321 is a copper wire, i.e. the metal wire S can be a copper wire, too. In other words, the metal wire does not include the coating layer, but the present disclosure does not limited thereto. For example, the metal wire body 321 can be an aluminum wire. In the present disclosure, preferably, the metal wire body 321 has a circular cross section, such that more sunlight can reach the cell substrate to further improve the photoelectric conversion efficiency.
In some specific embodiments of the present disclosure, the connection material layer coating the metal wire body 321 is the welding layer, which is an alloy layer. The alloy layer contains Sn and at least one of Bi, In, Ag, Sb, Pb and Zn. Preferably, the alloy contains Sn, Bi, and at least one of In, Ag, Sb, Pb and Zn.
In the alloy, based on the total weight of the alloy, the amount of Bi is 15 to 60 weight percent, Sn 30 to 75 weight percent, Cu 0 to 20 weight percent, In 0 to 40 weight percent, Ag 0 to 3 weight percent, Sb 0 to 20 weight percent, Pb 0 to 10 weight percent, and Zn 0 to 20 weight percent.
Further, the alloy is at least one selected from 50% Sn-48% Bi-1.5% Ag-0.5% Cu, 58% Bi-42% Sn and 65% Sn-20% Bi-10% Pb-5% Zn.
Alternatively, the alloy layer has a thickness of 1 to 100 μm, and the conductive wire has a cross section of 0.01 to 0.5 mm².
In some specific embodiments of the present disclosure, the method further includes applying a welding layer to a position where the conductive wire 32 is welded with the cell 31, before the conductive wires constituted by the metal wire and the cell are welded by high-frequency welding.
The welding layer can be disposed on the cell 31, or the metal wire body 321. Preferably, the welding layer is disposed on the metal wire body 321. In other words, in the present disclosure, the metal wire body 321 is coated with the welding layer, i.e. the connection material layer 322 is the welding layer. Preferably, the ratio of a thickness of the welding layer and a diameter of the metal wire body 321 is (0.02-0.5):1.
The welding layer may be a metal with a lower melting point or an alloy. The tin alloy can be a conventional tin alloy, for example, containing Sn, and at least one of Bi, Pb, Ag and Cu, more specifically, i.e. SnBi, SnPb, SnBiCu, SnPbAg, etc, so as to avoid insufficient soldering between the conductive wires 32 and the secondary grid lines 312 and/or the back electrodes 314 of the cell, and to render the solar cell module higher photoelectric conversion efficiency.
In some embodiments, preferably, before the metal wire and the cell are high-frequency welded, the metal wire extends under a strain, i.e. straightening the metal wire. After the metal wire is connected with the secondary grid lines and the back electrodes of the cell, the strain of the metal wire can be released, so as to further avoid the drifting of the conductive wires when the solar cell module is manufactured, and to guarantee the photoelectric conversion efficiency.
In some specific embodiments of the present disclosure, the secondary grid line has a width of 40 to 80 μm and a thickness of 5 to 20 μm; there are 50 to 120 secondary grid lines, a distance between adjacent secondary grid lines ranging from 0.5 to 3 mm. thus, the structure of the secondary grid lines 312 is more reasonable, so as to obtain a larger sunlight area and higher photoelectric conversion efficiency.
FIG. 5 is a schematic diagram of a solar cell array according to another embodiment of the present disclosure. As shown in FIG. 5, the metal wire extends reciprocally between the front surface of the first cell 31A and the front surface of the second cell 31B, such that the metal wire constitutes front conductive wires 32A of the first cell 31A and back conductive wires 2B of the second cell 31B. In such a way, the first cell 31A and the second cell 31B are connected in parallel. Of course, it can be understood that preferably the back electrodes of the first cell 31A and the back electrodes of the second cell 31B can be connected via back conductive wires constituted by another metal wire which extends reciprocally. Alternatively, the back electrodes of the first cell 31A and the back electrodes of the second cell 31B can be connected in a traditional manner.
In some embodiments of the present disclosure, in the cell array 30, the cell 31 can be a conventional cell 31 in the art, for example, a polycrystalline silicon cell 31. The secondary grid lines 312 on the shiny surface of the cell 31 can be Ag, Cu, Sn, and tin alloy. The secondary grid line 312 has a width of 40 to 80 μm and a thickness of 5 to 20 μm; there are 50 to 120 secondary grid lines, a distance between adjacent secondary grid lines ranging from 0.5 to 3 mm.
The back electrodes 314 on the back surface of the cell 31 can be made of Ag, Cu, Sn and tin alloys. The back electrodes 314 are usually in a ribbon pattern, and have a width of 1 to 4 mm, and a thickness of 5 to 20 μm.
FIG. 12 shows a schematic diagram of a solar cell array according to another embodiment of the present disclosure. As shown in FIG. 12, short grid lines 33 and secondary grid lines 312 are disposed at the front surface of the cell 31; the secondary grid lines 312 include middle secondary grid lines intersected with the conductive wires and edge secondary grid lines non-intersected with the conductive wires; the short lines 33 are connected with the edge secondary grid lines, and connected with the conductive wires or at least one middle secondary grid line. Preferably, the short grid lines 33 are perpendicular to the secondary grid lines 312.
Consequently, the short grid lines 33 are disposed at the edges of the shiny surface of the cell 31, so as to avoid partial current loss because the conductive wires 32 cannot reach the secondary grid lines 312 at the edges of the cell 31 in the winding process, and to further improve the photoelectric conversion efficiency of the solar cell module 100.
The solar cell array 30 according to another embodiment of the present disclosure is illustrated with reference to FIG. 6.
The solar cell array 30 according to the embodiment of the present disclosure comprises n×m cells 31. In other words, a plurality of cells 31 are arranged in an n×m matrix form, n representing a column, and m representing a row. More specifically, in the embodiment, 36 cells 31 are arranges into six columns and six rows, i.e. n=m=6. It can be understood that the present disclosure is not limited thereto. For example, the column number and the row number can be different. For convenience of description, in FIG. 6, in a direction from left to right, the cells 31 in one row are called a first cell 31, a second cell 31, a third cell 31, a fourth cell 31, a fifth cell 31, and a sixth cell 31 sequentially; in a direction from up to down, the columns of the cells 31 are called a first column of cells 31, a second column of cells 31, a third column of cells 31, a fourth column of cells 31, a fifth column of cells 31, and a sixth column of cells 31 sequentially.
In a row of the cells 31, the metal wire extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31; in two adjacent rows of cells 31, the metal wire extends reciprocally between a surface of a cell 31 in a a^throw and a surface of a cell 31 in a (a+1)^throw, and m−1≧a≧1.
As shown in FIG. 6, in a specific example, in a row of the cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31, so as to connect the cells 31 in one row in series. In two adjacent rows of cells 31, the metal wire extends reciprocally between a front surface of a cell 31 at an end of the a^throw and a back surface of a cell 31 at an end of the (a+1)^throw, to connect the two adjacent rows of cells 31 in series.
More preferably, in the two adjacent rows of cells 31, the metal wire extends reciprocally between the surface of the cell 31 at an end of the a^throw and the surface of the cell 31 at an end of the (a+1)^throw, the end of the a^throw and the end of the (a+1)^throw located at the same side of the matrix form, as shown in FIG. 6, located at the right side thereof.
More specifically, in the embodiment as shown in FIG. 6, in the first row, a first metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31; a second metal wire extends reciprocally between a front surface of the second cell 31 and a back surface of a third cell 31; a third metal wire extends reciprocally between a front surface of the third cell 31 and a back surface of a fourth cell 31; a fourth metal wire extends reciprocally between a front surface of the fourth cell 31 and a back surface of a fifth cell 31; a fifth metal wire extends reciprocally between a front surface of the fifth cell 31 and a back surface of a sixth cell 31. In such a way, the adjacent cell bodies 31 in the first row are connected in series by corresponding metal wires.
A sixth metal wire extends reciprocally between a front surface of the sixth cell 31 in the first row and a back surface of a sixth cell 31 in the second row, such that the first row and the second row are connected in series. A seventh metal wire extends reciprocally between a front surface of the sixth cell 31 in the second row and a back surface of a fifth cell 31 in the second row; a eighth metal wire extends reciprocally between a front surface of the fifth cell 31 in the second row and a back surface of a fourth cell 31 in the second row, until a eleventh metal wire extends reciprocally between a front surface of a second cell 31 in the second row and a back surface of a first cell 31 in the second row, and then a twelfth metal wire extends reciprocally between a front surface of the first cell 31 in the second row and a back surface of a first cell 31 in the third row, such that the second row and the third row are connected in series. Sequentially, the third row and the fourth row are connected in series, the fourth row and the fifth row connected in series, the fifth row and the sixth row connected in series, such that the cell array 30 is manufactured. In this embodiment, a bus bar is disposed at the left side of the first cell 31 in the first row and the left side of the first cell 31 in the sixth row respectively; a first bus bar is connected with the conductive wires extending from the left side of the first cell 31 in the first row, and a second bus bar is connected with the conductive wires extending from the left side of the first cell 31 in the sixth row.
As said above, the cell bodies in the embodiments of the present disclosure are connected in series by the conductive wires—the first row, the second row, the third row, the fourth row, the fifth row and the sixth row are connected in series by the conductive wires. As shown in the figures, alternatively, the second and third row, and the fourth and fifth rows can be connected in parallel with a diode respectively to avoid light spot effect. The diode can be connected in a manner commonly known to those skilled in the art, for example, by a bus bar.
However, the present disclosure is not limited to the above. For example, the first and second rows can be connected in series, the third and fourth rows connected in series, the fifth and sixth rows connected in series, and meanwhile the second and third rows are connected in parallel, the fourth and fifth connected in parallel. In such a case, a bus bar can be disposed at the left or right side of corresponding rows respectively.
Alternatively, the cells 31 in the same row can be connected in parallel. For example, a metal wire extends reciprocally from a front surface of a first cell 31 in a first row through the front surfaces of the second to the sixth cells 31.
In the following, the conductive adhesive 322 coating the metal wire body 321 will be described in detail.
According to an embodiment of the present disclosure, the conductive adhesive 322 contains thermosetting resin and conductive particles, and the thermosetting resin has a curing temperature lower than a melting temperature of the front adhesive layer and the back adhesive layer. Thus, it can be guaranteed that the conductive adhesive 322 is cured and bound with the cell 31 before the front adhesive layer 20 melts.
Preferably, the thermosetting resin has a curing temperature of 20 to 80° C. Especially, when the adhesive layer is made of polyethylene-octene elastomer (POE) and/or ethylene-vinyl acetate copolymer (EVA), the thermosetting resin whose curing temperature falls in the above range can obtain a better effect. For example, the solar cell module 100 may have higher photoelectric conversion efficiency.
In the present disclosure, the thermosetting resin whose curing temperature falls in the above preferable range is at least one of epoxy resin and acrylic resin.
Preferably, in the conductive adhesive 322, a content of the thermosetting resin is 10 to 40 weight percent and a content of the conductive particles is 60 to 90 weight percent, based on the total weight of the conductive adhesive 322.
Further, the conductive particles can be common metal particles for forming the conductive adhesive 322, such as silver powders and/or gold powders. The conductive particle has a diameter of 0.1 to 20 μm, preferably 1 to 10 μm. The welding layer has a thickness of 1 to 100 μm, and the metal wire has a cross section of 0.01 to 0.5 mm². Thus, there is a better connection effect between the conductive adhesive 322 and the cell 31 of the structure, so as to prevent the conductive wires 32 from drifting.
In some specific embodiments of the present disclosure, the binding force between the metal wire and the cells 31 ranges from 0.1N to 0.8N. That's to say, the binding force between the conductive wires 32 and the cells 31 ranges from 0.1N to 0.8N. Preferably, the binding force between the metal wire and the cells ranges from 0.2N to 0.6N. so as to secure the welding between the cells and the metal wire, to avoid sealing-off of the cells in the operation and the transferring process and performance degradation due to poor connection, and to lower the cost.
In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has a series resistance of 380 to 440 mΩ per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. When there are 72 cells, the series resistance of the solar cell module is 456 to 528 mΩ, and the electrical performance of the cells is better.
In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has an open-circuit voltage of 37.5-38.5V per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. The short-circuit current is 8.9 to 9.4 A, and is not related to the number of the cells.
In some specific embodiments of the present disclosure, the solar cell module has a fill factor of 0.79 to 0.82, which is independent from the dimension and number of the cells, and can affect the electrical performance of the cells.
In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has a working voltage of 31.5-32V per 60 cells. The present disclosure is not limited to 60 cells, and there may be 30 cells, 72 cells, etc. The working current is 8.4 to 8.6 A, and is not related to the number of the cells.
In some specific embodiments of the present disclosure, for a typical cell with a dimension of 156 mm×156 mm, the solar cell module has a conversion efficiency of 16.5-17.4%, and a power of 265-280 W per 60 cells.
A method for manufacturing the solar cell module 100 according to the embodiments of the present disclosure will be illustrated with respect to FIG. 7 to FIG. 9.
Specifically, the method includes the following steps: forming a plurality of conductive wires 32 by a metal wire which extends reciprocally between a surface of a first cell 31 and a surface of a second cell 31 adjacent to the first cell 31, welding the plurality of the conductive wires 32 with the secondary grid lines 312 on the front surface of the cell 31, such that adjacent cells 31 are connected by the conductive wires 32 to obtain the cell array; superposing an upper cover plate 10, a front adhesive layer 20, the cell array 30, a back adhesive layer 40 and a back plate 50 in sequence, in which the front surface of the cell 31 faces the front adhesive layer 20, and the back surface thereof faces the back adhesive layer 40, and laminating them to obtain the solar cell module 100.
The method includes the steps of preparing a solar array 30, superposing the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 in sequence, and laminating them to obtain the solar cell module 100. It can be understood that the method further includes other steps, for example, sealing the gap between the upper cover plate 10 and the back plate 50 by a sealant, and fixing the above components together by a U-shape frame, which are known to those skilled in the art, and thus will be not described in detail herein.
The method includes a step of forming a plurality of conductive wires by a metal wire which extends reciprocally surfaces of cells 31 and is electrically connected with the surfaces of cells 31, such that the adjacent cells 31 are connected by the plurality of conductive wires to constitute a cell array 30.
Specifically, as shown in FIG. 7, the metal wire extends reciprocally for 12 times under a strain. As shown in FIG. 8, a first cell 31 and a second cell 31 are prepared. As shown in FIG. 9, a front surface of the first cell 31 is connected with a metal wire, and a back surface of the second cell 31 is connected with the metal wire, such that the cell array 30 is formed. FIG. 9 shows two cells 31. When the cell array 30 has a plurality of cells 31, the metal wire which extends reciprocally connects the front surface of the first cell 31 and the back surface of the second cell 31 adjacent to the first cell 31, i.e. connecting a secondary grid line of the first cell 31 with a back electrode of the second cell 31 by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof.
In the embodiment shown in FIG. 9, the adjacent cells are connected in series. As said above, the adjacent cells can be connected in parallel by the metal wire based on practical requirements.
The cell array 30 obtained is superposed with the upper cover plate 10, the front adhesive layer 20, the back adhesive layer 40 and the back plate 50 in sequence, in which a front surface of the cell 31 faces the front adhesive layer 20, a back surface thereof facing the back adhesive layer 40, and laminating them to obtain the solar cell module 100. It can be understood that the metal wire can be welded with the cell 31 when or before they are laminated.
According to another embodiment of the present disclosure, the method includes the following steps:
welding a conductive wire 323 constituted by a metal wire S with a secondary grid line 312 of a cell 31 via a welding layer disposed in a position where the conductive wire 32 and the secondary grid line 312 are welded, in which the welding layer is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, and an amount of Bi is 15 to 60 weight percent;
superposing an upper cover plate 10, a front adhesive layer 20, the cell 31, a back adhesive layer 40 and a back plate 50 in sequence, such that a front surface of the cell 31 faces the front adhesive layer 20, a back surface thereof facing the back adhesive layer 40, and laminating them to obtain the solar cell module 100.
The method includes the steps of preparing a solar array 30, superposing the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 in sequence, and laminating them to obtain the solar cell module 100. It can be understood that the method further includes other steps, for example, sealing the gap between the upper cover plate 10 and the back plate 50 by a sealant, and fixing the above components together by a U-shape frame 60, which are known to those skilled in the art, and thus will be not described in detail herein.
The method includes a step of forming a plurality of conductive wires by a metal wire which extends reciprocally surfaces of cells 31 and is electrically connected with the surfaces of cells 31, such that the adjacent cells 31 are connected by the plurality of conductive wires to constitute a cell array 30.
Specifically, as shown in FIG. 7, the metal wire extends reciprocally for 12 times under a strain. As shown in FIG. 8, a first cell 31 and a second cell 31 are prepared. As shown in FIG. 9, a front surface of the first cell 31 is connected with a metal wire, and a back surface of the second cell 31 is connected with the metal wire, such that the cell array 30 is formed. FIG. 9 shows two cells 31. When the cell array 30 has a plurality of cells 31, the metal wire which extends reciprocally connects the front surface of the first cell 31 and the back surface of the second cell 31 adjacent to the first cell 31, i.e. connecting a secondary grid line of the first cell 31 with a back electrode of the second cell 31 by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof.
In the embodiment shown in FIG. 9, the adjacent cells are connected in series. As said above, the adjacent cells can be connected in parallel by the metal wire based on practical requirements.
The cell array 30 obtained is superposed with the upper cover plate 10, the front adhesive layer 20, the back adhesive layer 40 and the back plate 50 in sequence, in which a front surface of the cell 31 faces the front adhesive layer 20, a back surface thereof facing the back adhesive layer 40, and laminating them to obtain the solar cell module 100. It can be understood that the metal wire S can be welded with the cell 31 when or before they are laminated. Preferably, the conductive wires 32 and the secondary grid lines 312 are welded before or after they are superposed, and the conductive wires 32 and the secondary grid lines 312 are welded when or after they are laminated.
According to another embodiment of the present disclosure, the method includes the steps of applying a conductive adhesive 322 to a metal wire body 321 to form a metal wire S; forming a plurality of conductive wires 32 by a metal wire S which extends reciprocally between surfaces of the cells 31 and contacts with the surfaces of the cells 31, in which the conductive wires 32 are connected with secondary grid lines 312 of the cell 31 via the conductive adhesive 322, such that adjacent cells 31 are connected by the plurality of conductive wires 32 to form a cell array 30; superposing an upper cover plate 10, a front adhesive layer 20, the cell array 30, a back adhesive layer 40 and a back plate 50 in sequence, in which a front surface of the cell 31 faces the front adhesive layer 20, such that the front adhesive layer 20 contacts with the conductive wires 32 directly and fills between adjacent conductive wires 32; and a back surface of the cell 31 faces the back adhesive layer 40, and laminating them to obtain the solar cell module 100.
In other words, in the process of manufacturing the solar cell module 100, the metal wire body 321 is first coated with a conductive adhesive 322 to form a metal wire S, and then the metal wire S extends reciprocally between the surfaces of the adjacent cells 31 and contacts with the surfaces of the cells 31 to constitute a plurality of conductive wires 32. The conductive wires 32 and the cell 31 are connected by the conductive adhesive 322. The multiple cells 31 are connected to form the cell array 30.
Then, the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 are superposed in sequence, in which the front adhesive layer 20 contacts with the conductive wires 32 directly and fills between adjacent conductive wires 32. Finally, the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 are laminated to obtain the solar cell module 100 said above.
Specifically, as shown in FIG. 7, the metal wire extends reciprocally for 12 times under a strain. As shown in FIG. 8, a first cell 31A and a second cell 31B are prepared. As shown in FIG. 9, a front surface of the first cell 31A is connected with a metal wire, and a back surface of the second cell 31B is connected with the metal wire, so as to form a cell array 30. FIG. 9 shows two cells 31. As above, when the cell array 30 has a plurality of cells 31, the metal wire extends reciprocally to connect the front surface of the first cell 31 and the back surface of the second cell 31 adjacent to the first cell 31, i.e. connecting secondary grid lines of the first cell 31 with back electrodes of the second cell 31 by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof. In the embodiment shown in FIG. 9, the adjacent cells are connected in series. As above, the adjacent cells can be connected in parallel by the metal wire in the light of practical requirements.
The cell array 30 obtained is superposed with the upper cover plate 10, the front adhesive layer 20, the back adhesive layer 40 and the back plate 50 in sequence, in which the front surfaces of the cells 31 face the front adhesive layer 20, such that the front adhesive layer 20 contacts with the conductive wires 32 directly and fills between adjacent conductive wires 32; the back surfaces of the cells 31 face the back adhesive layer 40, and then they are laminated to obtain the solar cell module 100. It can be understood that the metal wire can be bound or welded with the cells 31, and the connection of the metal wire and the cells 31 can be conducted in the laminating process. Of course, they can be first connected and then laminated.
According to another embodiment of the present disclosure, a method for manufacturing the solar cell module 100 will be illustrated with respect to FIG. 7 to FIG. 9.
The method includes the steps of melting a conductive wire formed of a metal wire into a transparent film, in which the conductive wire comes out from the transparent film; superposing an upper cover plate 10, a front adhesive layer 20, the transparent film 60, the cell 31, a back adhesive layer 40 and a back plate 50 in sequence, and laminating them to obtain the solar cell module 100, in which the conductive wire 32 contacts with the secondary grid line 312 of the cell 31, and the transparent film 60 has a melting point higher than the melting point of the front adhesive layer 20 and the back adhesive layer 40.
In other words, when the solar cell module 100 of the present disclosure is manufactured, the conductive wires 32 are arranged in the surface of the transparent film 60; then the conductive wires 32 are heated (e.g. electrical heating), such that the contact portion of the transparent film 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film 60 together, and the metal wire comes out from the transparent film 60.
Then, the upper cover plate 10, the front adhesive layer 20, the transparent film 60, the cell 31, the back adhesive layer 40 and the back plate 50 are superposed in sequence. The secondary grid lines 312 on the front surface of the cell 31 are in direct contact with the conductive wires 32. The upper cover plate 10, the front adhesive layer 20, the transparent film 60, the cell 31, the back adhesive layer 40 and the back plate 50 are laminated to obtain the solar cell module 100 said above in the present disclosure.
Preferably, a first end of the conductive wire is arranged on the lower surface of the first transparent film 60, and a second end of the conductive wire is arranged on the upper surface of the second transparent film 60, and then the conductive wire is heated (e.g. electrical heating), such that the contact portion of the transparent film 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film 60 together. The first transparent film 60 whose lower surface is melted with the conductive wires faces a front surface of a first cell 31, such that the conductive wires 32 are connected with the secondary grid lines 312 on the front surface of the first cell; the second transparent film 60 whose upper surface is melted with the conductive wires faces a back surface of a second cell 31, such that the conductive wires 32 are connected with the back electrodes 314 on the back surface of the second cell; part of the conductive wires 32 welded with the secondary grid lines on the front surface of the first cell are called front conductive wires 32A, and part of the conductive wires 32 welded with the back electrodes on the back surface of the second cell are called back conductive wires 32B.
The upper cover plate 10, the front adhesive layer 20, the transparent film 60, the cell 31, the back adhesive layer 40 and the back plate 50 are superposed in sequence. The secondary grid lines 312 on the front surface of the first cell 31 are in direct contact with and connected with the conductive wires 32 via the connection material layer 322. The back electrodes 314 on the back surface of the second cell 31 are in direct contact with and connected with the conductive wires 32 via the connection material layer 322. The upper cover plate 10, the front adhesive layer 20, the transparent film 60, the cell 31, the back adhesive layer 40 and the back plate 50 are laminated to obtain the solar cell module 100 said above in the present disclosure.
Specifically, as shown in FIG. 7, the metal wire extends reciprocally for 12 times under a strain, and then melts to be connected with the transparent film 60. As shown in FIG. 8, a first cell 31A and a second cell 31B are prepared. As shown in FIG. 9, a front surface of the first cell 31A is connected with a metal wire, and a back surface of the second cell 31B is connected with the metal wire, so as to form a cell array 30. FIG. 9 shows two cells 31. As above, when the cell array 30 has a plurality of cells 31, the metal wire extends reciprocally to connect the front surface of the first cell 31 and the back surface of the second cell 31 adjacent to the first cell 31, i.e. connecting secondary grid lines of the first cell 31 with back electrodes of the second cell 31 by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof.
In the embodiment shown in FIG. 9, the adjacent cells are connected in series. As above, the adjacent cells can be connected in parallel by the metal wire in the light of practical requirements.
The cell array 30 obtained is superposed with the upper cover plate 10, the front adhesive layer 20, the back adhesive layer 40 and the back plate 50 in sequence, in which the front surface of the cell 31 faces the transparent film 60; the conductive wires 32 on the transparent film 60 are in contact with the secondary grid lines 312 on the cell 31; and the back surface of the cell 31 faces the back adhesive layer 40. Then they are laminated to obtain the solar cell module 100.
According to another embodiment of the present disclosure, the method includes the steps of welding a conductive wire 32 constituted by a metal wire S into a transparent film, in which the metal wire comes out from the transparent film, and includes a metal wire body 321 and a connection material layer 322 applied to the metal wire body 321; superposing an upper cover plate 10, a front adhesive layer 20, the transparent film 60, the cell 31, a back adhesive layer 40 and a back plate 50 in sequence, and laminating them to obtain the solar cell module 100, in which the conductive wire 32 is connected with the secondary grid line 312 of the cell 31 via the connection material layer 322, and the transparent film 60 has a melting point higher than the melting point of the front adhesive layer 20 and the back adhesive layer 40.
In other words, when the solar cell module 100 of the present application is manufactured, the conductive wires 32 are arranged in the surface of the transparent film 60, and are constituted by the metal wire S which consists of a metal wire body 321 and a connection material layer 322 coating the metal wire body 321. Then the conductive wires 32 are heated (e.g. electrical heating), such that the contact portion of the transparent film 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film 60 together, and the metal wire comes out from the transparent film 60.
Then, the upper cover plate 10, the front adhesive layer 20, the transparent film 60, the cell 31, the back adhesive layer 40 and the back plate 50 are superposed in sequence. The secondary grid lines 312 on the front surface of the cell 31 are in direct contact with the conductive wires 32. The upper cover plate 10, the front adhesive layer 20, the transparent film 60, the cell 31, the back adhesive layer 40 and the back plate 50 are laminated to obtain the solar cell module 100 said above in the present application.
Preferably, a first end of the conductive wire is arranged on the lower surface of the first transparent film 60, and a second end of the conductive wire is arranged on the upper surface of the second transparent film 60, and then the conductive wire is heated (e.g. electrical heating), such that the contact portion of the transparent film 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film 60 together. The first transparent film 60 whose lower surface is melted with the conductive wires faces a front surface of a first cell 31, such that the conductive wires 32 are connected with the secondary grid lines 312 on the front surface of the first cell; the second transparent film 60 whose upper surface is melted with the conductive wires faces a back surface of a second cell 31, such that the conductive wires 32 are connected with the back electrodes 314 on the back surface of the second cell; part of the conductive wires 32 welded with the secondary grid lines on the front surface of the first cell are called front conductive wires 32A, and part of the conductive wires 32 welded with the back electrodes on the back surface of the second cell are called back conductive wires 32B.
The upper cover plate 10, the front adhesive layer 20, the transparent film 60, the cell 31, the back adhesive layer 40 and the back plate 50 are superposed in sequence. The secondary grid lines 312 on the front surface of the first cell 31 are in direct contact with and connected with the conductive wires 32 via the connection material layer 322. The back electrodes 314 on the back surface of the second cell 31 are in direct contact with and connected with the conductive wires 32 via the connection material layer 322. The upper cover plate 10, the front adhesive layer 20, the transparent film 60, the cell 31, the back adhesive layer 40 and the back plate 50 are laminated to obtain the solar cell module 100 said above in the present application.
Specifically, as shown in FIG. 7, the metal wire extends reciprocally for 12 times under a strain, and then melts to be connected with the transparent film 60. As shown in FIG. 8, a first cell 31A and a second cell 31B are prepared. As shown in FIG. 9, a front surface of the first cell 31A is connected with a metal wire, and a back surface of the second cell 31B is connected with the metal wire, so as to form a cell array 30. FIG. 9 shows two cells 31. As above, when the cell array 30 has a plurality of cells 31, the metal wire extends reciprocally to connect the front surface of the first cell 31 and the back surface of the second cell 31 adjacent to the first cell 31, i.e. connecting secondary grid lines of the first cell 31 with back electrodes of the second cell 31 by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof.
In the embodiment shown in FIG. 9, the adjacent cells are connected in series. As above, the adjacent cells can be connected in parallel by the metal wire in the light of practical requirements.
The cell array 30 obtained is superposed with the upper cover plate 10, the front adhesive layer 20, the back adhesive layer 40 and the back plate 50 in sequence, in which the front surface of the cell 31 faces the transparent film 60; the conductive wires 32 on the transparent film 60 are in contact with the secondary grid lines 312 on the cell 31; and the back surface of the cell 31 faces the back adhesive layer 40. Then they are laminated to obtain the solar cell module 100.
According to another embodiment of the present disclosure, The method includes the steps of binding a metal wire S with a longitudinal adhesive tape 61 on a transparent film frame 60 constituted by the longitudinal adhesive tape 61 and a transverse adhesive tape 62; superposing an upper cover plate 10, a front adhesive layer 20, the transparent film frame 60, a cell 31, a back adhesive layer 40 and a back plate 50 in sequence, in which the front surface of the cell faces the front adhesive layer 20, a back surface thereof facing the back adhesive layer 40, and laminating them to obtain the solar cell module 100, the metal wire S connected with a secondary grid line 312 of a cell 31 in the cell array 30.
Alternatively, in some specific embodiments of the present application, the metal wire S and the longitudinal adhesive tape 61 are bound before the metal wire S is connected with the secondary grid line 312. In some other specific embodiments of the present application, the metal wire S is connected with the secondary grid line 312 when they are laminated.
In other words, when the solar cell module 100 of the present application is manufactured, the conductive wires 32 are arranged in the surface of the transparent film frame 60; then the conductive wires 32 are heated (e.g. electrical heating), such that the contact portion of the transparent film frame 60 and the conductive wires 32 is softened or melted, so as to melt and fix the conductive wires 32 and the transparent film frame 60 together, and the metal wire comes out from the transparent film frame 60.
Then, the upper cover plate 10, the front adhesive layer 20, the transparent film frame 60, the cell 31, the back adhesive layer 40 and the back plate 50 are superposed in sequence. The secondary grid lines 312 on the front surface of the cell 31 are in direct contact with the conductive wires 32. The upper cover plate 10, the front adhesive layer 20, the transparent film frame 60, the cell 31, the back adhesive layer 40 and the back plate 50 are laminated to obtain the solar cell module 100 said above in the present application.
Specifically, as shown in FIG. 7, the metal wire extends reciprocally for 12 times under a strain, and then melts to be connected with the transparent film frame 60. As shown in FIG. 8, a first cell 31A and a second cell 31B are prepared. As shown in FIG. 9, a front surface of the first cell 31A is connected with a metal wire, and a back surface of the second cell 31B is connected with the metal wire, so as to form a cell array 30. FIG. 9 shows two cells 31. As above, when the cell array 30 has a plurality of cells 31, the metal wire extends reciprocally to connect the front surface of the first cell 31 and the back surface of the second cell 31 adjacent to the first cell 31, i.e. connecting secondary grid lines of the first cell 31 with back electrodes of the second cell 31 by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof.
In the embodiment shown in FIG. 9, the adjacent cells are connected in series. As above, the adjacent cells can be connected in parallel by the metal wire in the light of practical requirements.
The cell array 30 obtained is superposed with the upper cover plate 10, the front adhesive layer 20, the back adhesive layer 40 and the back plate 50 in sequence, in which the front surface of the cell 31 faces the transparent film frame 60; the conductive wires 32 on the transparent film frame 60 are in contact with the secondary grid lines 312 on the cell 31; and the back surface of the cell 31 faces the back adhesive layer 40. Then they are laminated to obtain the solar cell module 100. According to another embodiment of the present disclosure, the method includes the following steps: connecting adjacent cells by conductive wires 32 constituted by a metal wire S to form a cell array, the conductive wires 32 being connected with front secondary grid lines 312A of the cell, and a connection material layer 3121 being disposed at a position where the front secondary grid lines 312A are connected with the conductive wires 32.
Preferably, the metal wire S extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 adjacent to the first cell 31; the metal wire S is welded with the front secondary grid line 312A of the first cell 31 by the connection material layer 3121, and connected with the a back electrode on a back surface of the second cell 31, so as to form a cell array.
The connection material layer can be a welding layer or a conductive adhesive, and the welding layer can be an alloy with low melting point.
Then, the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 are superposed in sequence, in which the front surface of the cell 31 faces the front adhesive layer 20, the back surface thereof facing the back adhesive layer 4. Finally, they are laminated to obtain the solar cell module 100.
The method includes the steps of preparing a solar array 30, superposing the upper cover plate 10, the front adhesive layer 20, the cell array 30, the back adhesive layer 40 and the back plate 50 in sequence, and laminating them to obtain the solar cell module 100. It can be understood that the method further includes other steps, for example, sealing the gap between the upper cover plate 10 and the back plate 50 by a sealant, and fixing the above components together by a U-shape frame, which are known to those skilled in the art, and thus will be not described in detail herein.
The method includes a step of forming a plurality of conductive wires by a metal wire which extends reciprocally surfaces of cells 31 and is electrically connected with the surfaces of cells 31, such that the adjacent cells 31 are connected by the plurality of conductive wires to constitute a cell array 30.
Specifically, as shown in FIG. 7, the metal wire extends reciprocally for 12 times under a strain. As shown in FIG. 8, a first cell 31A and a second cell 31B are prepared. As shown in FIG. 9, a front surface of the first cell 31A is connected with a metal wire, and a back surface of the second cell 31B is connected with the metal wire, such that the cell array 30 is formed. FIG. 9 shows two cells 31. As said above, when the cell array 30 has a plurality of cells 31, the metal wire which extends reciprocally connects the front surface of the first cell 31A and the back surface of the second cell 31B adjacent to the first cell 31A, i.e. connecting secondary grid lines of the first cell 31A with back electrodes of the second cell 31B by the metal wire. The metal wire extends reciprocally under a strain from two clips at two ends thereof.
In the embodiment shown in FIG. 9, the adjacent cells are connected in series. As said above, the adjacent cells can be connected in parallel by the metal wire based on practical requirements. The cell array 30 obtained is superposed with the upper cover plate 10, the front adhesive layer 20, the back adhesive layer 40 and the back plate 50 in sequence, in which the front surface of the cell 31 faces the front adhesive layer 20, and the back surface thereof faces the back adhesive layer 40, and then they are laminated to obtain the solar cell module 100. It can be understood that the metal wire can be bounded or welded with the cell 31 when or before they are laminated.
In the following, the solar cell module 100 of the present disclosure will be described with respect to specific examples.

Example 1

Example 1 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
An alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.04 mm², and the alloy layer has a thickness of 16 μm. Hence, the metal wire S is obtained.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness) on its front surface, each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31 in a row, a metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under a strain. The metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The distance between parallel adjacent conductive wires is 9.9 mm. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer 20, the back surface of the cell 31 facing the back adhesive layer 40, and the conductive wires 32 are connected with the cell 31 by high-frequency welding, and finally they are laminated in a laminator. In such way, a solar cell module A1 is obtained.

Example 2

Example 2 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
An alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.04 mm², and the alloy layer has a thickness of 16 μm. Hence, the metal wire S is obtained.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness) on its front surface, each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31 in a row, a metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under a strain. The metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The secondary grid lines of the first cell 31 are welded with the conductive wires and the back electrodes of the second cell 31 are welded with the conductive wires. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer 20, such that the front adhesive layer 20 contacts with the conductive wires 32 directly; and the backy surface of the cell 31 faces the back adhesive layer 40, and finally they are laminated in a laminator, in which the front adhesive layer 20 fills between adjacent conductive wires 32. In such way, a solar cell module A1 is obtained.

Comparison Example 1

The differences between Comparison example 1 and Example 2 lie in that the conductive wires and the cell are connected by far infrared welding. In such a way, a solar cell module D1 is obtained.

Example 3

The solar cell module is manufactured according to the method in Example 2, but the difference compared with Example 2 lies in that a short grid line 33 (silver, 0.1 mm in width) is disposed on the secondary grid line of the shiny surface of the cell 31, and is perpendicular to the secondary grid line for connecting part of the secondary grid line at the edge of the shiny surface of the cell with the conductive wire, as shown in FIG. 12, so as to obtain a solar cell module A3.

Example 4

The solar cell module is manufactured according to the method in Example 2, but the difference compared with Example 2 lies in that the cells of six columns and ten rows are connected in such a manner that in two adjacent rows of cells, the conductive wires extends from a shiny surface of a cell 31 at an end of the a^throw (a≧1) to form electrical connection with a back surface of a cell 31 at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows of cells 31 are arranged in perpendicular to the conductive wires for connecting the adjacent cells 31 in the two rows. In such a way, the solar cell module A4 is obtained.

Testing Example 1

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes;
(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 1.

	TABLE 1

	Solar cell module

	A1	D1	A2	A3	A4

Metal wire	no	Greatly	no	no	no
drifting
phenomenon
Photoelectric	16.50%	15.30%	16.70%	17.00%	16.80%
conversion
efficiency
Series	458	515	445	433	448
resistance
(mΩ)
Fill factor	0.779	0.742	0.783	0.79	0.781
Open-circuit	37.65	37.52	37.75	37.86	37.81
voltage (V)
Short-circuit	9.048	8.836	9.085	9.143	9.154
current (A)
Working	31.15	30.32	31.34	31.76	31.69
voltage (V)
Working	8.52	8.117	8.571	8.61	8.53
current (A)
Power (W)	265.4	246.1	268.6	273.4	270.3

The fill factor refers to a ratio of the power at the maximum power point of the solar cell module and the maximum power theoretically at zero resistance, and represents the proximity of the actual power with respect to the theoretic maximum power, in which the greater the value is, the higher the photoelectric conversion efficiency is. Generally, the series resistance is small, so the fill factor is great. The photoelectric conversion efficiency refers to a ratio of converting the optical energy into electric energy by the module under a standard lighting condition (1000 W/m²of light intensity). The series resistance is equivalent to the internal resistance of the solar module, in which the greater the value is, the poorer the performance of the module is. The fill factor represents a ratio of the actual maximum power and the theoretical maximum power of the module, in which the greater the value is, the better the performance of the module is. The open-circuit voltage refers to the voltage of the module in an open circuit under a standard lighting condition. The short-circuit current refers to the current of the module in a short circuit under a standard lighting condition. The working voltage is the output voltage of the module working with the largest power under a standard lighting condition. The working current is the output current of the module working with the largest power under a standard lighting condition. The power is the maximum power which the module can reach under a standard lighting condition.
It can be indicated from Table 1 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

Example 21

Example 21 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
An alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.04 mm², and the alloy layer has a thickness of 16 μm. Hence, the metal wire S is obtained.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1650×1000×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31 in a row, a metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under a strain. The metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The secondary grid lines of the first cell 31 are welded with the conductive wires and the back electrodes of the second cell 31 are welded with the conductive wires at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar.
The surfaces of the upper glass plate 10 and the lower glass plate facing the cell 31 are coated with silica gel, and then butyl rubber sealing rubber strips are stuck around the silica gel. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer 20, and the back surface of the cell 31 faces the back adhesive layer 40, and finally they are laminated in a laminator. In such way, a solar cell module A21 is obtained.

Comparison Example 21

The difference of Comparison example 21 and Example 21 lies in that the alloy layer is Sn63%-Pb37%, and the melting point is 183° C. In such way, a solar cell module D1 is obtained.

Example 22

The copper is coated with a Sn40%-Bi55%-Pb5% alloy layer on its surface. The cells 31 are arranged in a matrix form, and in two adjacent cells 31, each of the fifteen parallel metal wires, by wiredrawing, is welded with a secondary grid line on a front surface of a first cell 31 respectively, and welded with a back electrode on a back surface of a second cell 31. The distance between of the adjacent conductive wires in parallel to each other is 9.9 mm. In such a way, a solar cell module A22 is obtained.

Comparison Example 22

The differences between Comparison example 22 and Example 22 lie in that a Sn63%-Pb37% alloy layer is attached to the surface of the copper wire. In such a way, a solar cell module D2 is obtained.

Example 23

Example 23 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
An alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.03 mm², and the alloy layer has a thickness of 10 μm. Hence, the metal wire S is obtained.
(2) Manufacturing a Solar Cell Module
A EVA adhesive layer in 1630×980×0.5 mm is provided (melting point: 60° C.), and a glass plate in 1650×1000×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness) at its shiny surface, each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the two adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in the longitudinal direction, and the distance between the two adjacent back electrodes is 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31 in a row, a metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under a strain. The metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 20 parallel conductive wires. The secondary grid lines of the first cell 31 are welded with the conductive wires and the back electrodes of the second cell 31 are welded with the conductive wires at a welding temperature of 160° C. The distance between parallel adjacent conductive wires is 7 mm. Hence, 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar.
The surfaces of the upper glass plate 10 and the lower glass plate facing the cell 31 are coated with silica gel, and then butyl rubber sealing rubber strips are stuck around the silica gel. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer 20, and the back surface of the cell 31 faces the back adhesive layer 40, and finally they are laminated in a laminator. In such way, a solar cell module A23 is obtained.

Example 24

The solar cell module is manufactured according to the method in Example 21, but the difference compared with Example 1 lies in that a Sn42%-Bi58% alloy layer (melting point: 138° C.) is attached to the surface of the copper wire. In such a way, a solar cell module A24 is obtained.

Example 25

The solar cell module is manufactured according to the method in Example 21, but the difference compared with Example 1 lies in that a Sn45%-Bi45%-Zn10% alloy layer (melting point: 150° C.) is attached to the surface of the copper wire. In such a way, a solar cell module A25 is obtained.

Example 26

The solar cell module is manufactured according to the method in Example 21, but the difference compared with Example 1 lies in that a Sn42%-Bi57%-Ag1% alloy layer (melting point: 140° C.) is attached to the surface of the copper wire. In such a way, a solar cell module A26 is obtained.

Example 27

The solar cell module is manufactured according to the method in Example 21, but the difference compared with Example 1 lies in that the cells 31 are connected in such a manner that in two adjacent rows of cells, the conductive wires extends from a shiny surface of a cell 31 at an end of the a^throw (a≧1) to form electrical connection with a back surface of a cell 31 at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows of cells 31 are arranged in perpendicular to the conductive wires for connecting the adjacent cells 31 in the two rows. In such a way, the solar cell module A27 is obtained.

Testing Example 21

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes;
(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 2.

TABLE 2

Solar cell module	A21	D21	A22	D22	A23	A24	A25	A26	A27

Metal wire	no	Slightly	no	Slightly	no	no	no	no	no
drifting
phenomenon
Photoelectric	16.80%	15.5%	16.70%	15.3%	17.10%	17.20%	17.05%	17.30%	16.8%
conversion
efficiency
Series	451	498	445	515	442	427	445	425	448
resistance
(MΩ)
Fill factor	0.779	0.764	0.783	0.742	0.788	0.793	0.79	0.796	0.781
Open-circuit	37.84	37.44	37.75	37.52	37.85	37.9	37.71	37.94	37.81
voltage (V)
Short-circuit	9.166	8.712	9.085	8.836	9.22	9.198	9.206	9.212	9.154
current (A)
Working	31.54	30.49	31.34	30.32	31.86	31.97	31.84	31.92	31.69
voltage (V)
Working	8.568	8.176	8.571	8.117	8.633	8.651	8.611	8.717	8.53
current (A)
Power (W)	270.2	249.3	268.6	246.1	275	276.6	274.2	278.2	270.3

It can be indicated from Table 2 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

Example 31

Example 1 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
A copper wire is coated with a layer of epoxy resin conductive adhesive, in which the copper wire has a cross section of 0.04 mm², and the conductive adhesive has a thickness of 16 μm, so as to obtain the metal wire S.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm are provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31 in a row, a metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under a strain. The metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The distance between parallel adjacent conductive wires is 9.9 mm. 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer 20, such that the front adhesive layer 20 contacts with the conductive wires 32 directly and fills between the conductive wires 32; the back surface thereof faces the back adhesive layer 40, and they are laminated in a laminator so as to obtain the solar cell module A31.

Comparison Example 31

The difference of Comparison example 31 and Example 31 lies in that the cells 31 are arranged in a matrix form. 15 metal wires connected in series are stuck on the transparent adhesive film, and then stuck on the solar cell. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, the transparent adhesive film, multiple cells arranged in a matrix form and welded with the metal wire, the transparent adhesive film, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down. In such a way, a solar cell module D31 is obtained.

Example 32

Example 32 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
A copper wire is coated with a layer of acrylate conductive adhesive, in which the copper wire has a cross section of 0.03 mm², and the conductive adhesive has a thickness of 10 μm, so as to obtain the conductive wire.
(2) Manufacturing a Solar Cell Module
A EVA adhesive layer in 1630×980×0.5 mm are provided (melting point: 60° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells 31 are arranged in a matrix form (six rows and ten columns). In two adjacent cells 31 in a row, a metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under a strain. The metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 20 parallel conductive wires. The secondary grid lines of the first cell 31 are welded with the conductive wires, and the back electrodes of the second cell 31 are welded with the conductive wires. The distance between parallel adjacent conductive wires is 7 mm. Hence, 10 cells are connected in series into a row, and six rows of the cells of such kind are connected in series into a cell array via the bus bar. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer 20, such that the front adhesive layer 20 contacts with the conductive wires 32 directly and fills between the conductive wires 32; the back surface thereof faces the back adhesive layer 40, and they are laminated in a laminator so as to obtain the solar cell module A32.

Example 33

The solar cell module is manufactured according to the method in Example 31, but the difference compared with Example 1 lies in that the copper wire is coated with a layer of epoxy resin conductive adhesive whose thickness is 5 μm. In such a way, a solar cell module A33 is obtained.

Example 34

The solar cell module is manufactured according to the method in Example 31, but the difference compared with Example 31 lies in that the copper wire is coated with a layer of acrylate conductive adhesive whose thickness is 3 μm. In such a way, a solar cell module A34 is obtained.

Example 35

The solar cell module is manufactured according to the method in Example 32, but the difference compared with Example 2 lies in that the copper wire is coated with a layer of epoxy resin conductive adhesive whose thickness is 2 μm. In such a way, a solar cell module A35 is obtained.

Example 36

The solar cell module is manufactured according to the method in Example 32, but the difference compared with Example 32 lies in that a short grid line 33 (silver, 0.1 mm in width) is disposed on the secondary grid line of the shiny surface of the cell 31, and is perpendicular to the secondary grid line for connecting part of the secondary grid line at the edge of the shiny surface of the cell with the conductive wire, as shown in FIG. 12, so as to obtain a solar cell module A36.

Example 37

The solar cell module is manufactured according to the method in Example 32, but the difference compared with Example 32 lies in that the cells of six columns and six rows are connected in such a manner that in two adjacent rows of cells, the conductive wires extends from a shiny surface of a cell 31 at an end of the a^throw (a≧1) to form electrical connection with a back surface of a cell 31 at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows of cells 31 are arranged in perpendicular to the conductive wires for connecting the adjacent cells 31 in the two rows. In such a way, the solar cell module A37 is obtained.

Testing Example 31

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes;
(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 3.

TABLE 3

Solar cell module	A31	D31	A32	D32	A33	A34	A35	A36	A37

Metal wire	no	Slightly	no	Slightly	no	no	no	no	no
drifting
phenomenon
Photoelectric	16.70%	15.50%	17.10%	17.10%	17.05%	16.80%	17.20%	17.0%	16.70%
conversion
efficiency
Series	445	498	440	442	445	448	427	433	445
resistance
(mΩ)
Fill factor	0.783	0.764	0.792	0.788	0.79	0.781	0.793	0.79	0.783
Open-circuit	37.75	37.44	37.84	37.85	37.71	37.81	37.9	37.86	37.75
voltage (V)
Short-circuit	9.085	8.712	9.179	9.22	9.206	9.154	9.198	9.143	9.085
current (A)
Working	31.34	30.49	31.9	31.86	31.84	31.69	31.97	31.76	31.34
voltage (V)
Working	8.571	8.176	8.622	8.633	8.611	8.53	8.651	8.61	8.571
current (A)
Power (W)	268.6	249.3	275.1	275	274.2	270.3	276.6	273.4	268.6

It can be indicated from Table 3 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

Example 41

Example 41 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
A copper wire is used, in which the copper wire has a cross section of 0.04 mm².
The copper wire extends reciprocally under a strain from two clips at two ends of the copper wire, so as to form 15 parallel conductive wires. The distance between parallel adjacent metal wires is 9.9 mm.
Then part of the metal wires S are arranged in the surface of the transparent film made of a PET film; then the metal wires S are heated, such that the contact portion of the transparent film and the metal wires S is softened or melted, so as to melt and fix the metal wires S and the transparent film together, and the metal wires S come out from the transparent film.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and 60 polycrystalline silicon cells in 156×156×0.21 mm are provided correspondingly. The cells have 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cells in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. A Sn40%-Bi55%-Pb5% alloy layer is disposed at a portion of the secondary grid line which needs to be connected with the conductive wires. The cell has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells are arranged in a matrix form (six rows and ten columns). In two adjacent cells in the same row, the transparent film connected with the conductive wires by melting is disposed on a front surface of a first cell, and the secondary grid lines contact with the conductive wires. The other conductive wires which are welded extend onto a back surface of a second cell to be connected with the back electrodes on the back surface of the second cell.
Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell faces the front adhesive layer 20, and the back surface of the cell faces the back adhesive layer 40, and finally they are laminated in a laminator so as to obtain the solar cell module A41.

Comparison Example 41

The difference of Comparison example 41 and Example 41 lies in that the cells 31 are arranged in a matrix form. 15 metal wires connected in series are stuck on the transparent adhesive film, and then stuck on the solar cell. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, the transparent adhesive film, multiple cells arranged in a matrix form and welded with the metal wire, the transparent adhesive film, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down. In such a way, a solar cell module D41 is obtained.

Example 42

The solar cell module is manufactured according to the method in Example 41, but the difference compared with Example 41 lies in that a short grid line 33 (silver, 0.1 mm in width) is disposed on the secondary grid line of the shiny surface of the cell 31, and is perpendicular to the secondary grid line for connecting part of the secondary grid line at the edge of the shiny surface of the cell with the conductive wire, as shown in FIG. 12, so as to obtain a solar cell module A42.

Example 43

The solar cell module is manufactured according to the method in Example 41, but the difference compared with Example 41 lies in that the cells of six columns and six rows are connected in such a manner that in two adjacent rows of cells, the conductive wires extends from a shiny surface of a cell at an end of the a^throw (a≧1) to form electrical connection with a back surface of a cell at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows of cells are arranged in perpendicular to the conductive wires for connecting the adjacent cells in the two rows. In such a way, the solar cell module A43 is obtained.

Testing Example 41

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes;
(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 4.

	TABLE 4

	Solar cell module

	A41	D41	A42	A43

Metal wire drifting	no	Slightly	no	no
phenomenon
Photoelectric	16.5%	15.3%	16.7%	16.9%
conversion
efficiency
Series resistance	458	515	445	439
(mΩ)
Fill factor	0.779	0.742	0.783	0.791
Open-circuit voltage	37.65	37.52	37.75	37.78
(V)
Short-circuit current	9.048	8.836	9.085	9.094
(A)
Working voltage	31.15	30.32	31.34	31.62
(V)
Working current (A)	8.52	8.117	8.571	8.597
Power (W)	265.4	246.1	268.6	271.8

It can be indicated from Table 4 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

Example 51

Example 51 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
A copper wire is coated with a Sn40%-Bi55%-Pb5% alloy layer, in which the copper wire has a cross section of 0.04 mm², and the conductive adhesive has a thickness of 16 μm, so as to obtain the metal wire S.
The metal wire extends reciprocally under a strain from two clips at two ends of the copper wire, so as to form 15 parallel conductive wires. The distance between parallel adjacent conductive wires is 9.9 mm.
Then part of the conductive wires are arranged in the surface of the transparent film made of a PET film; then the conductive wires are heated, such that the contact portion of the transparent film and the conductive wires is softened or melted, so as to melt and fix the conductive wires and the transparent film together, and the metal wire comes out from the transparent film.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 in width, 9 in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells are arranged in a matrix form (six rows and ten columns). In two adjacent cells in the same row, the transparent film connected with the conductive wires by melting is disposed on a front surface of a first cell, and the secondary grid lines contact with the conductive wires. The other conductive wires which are welded extend onto a back surface of a second cell to be connected with the back electrodes on the back surface of the second cell.
Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell faces the front adhesive layer 20, and the back surface of the cell faces the back adhesive layer 40, and finally they are laminated in a laminator so as to obtain the solar cell module A51.

Comparison Example 51

The difference of Comparison example 51 and Example 51 lies in that the cells 31 are arranged in a matrix form. 15 metal wires connected in series are stuck on the transparent adhesive film, and then stuck on the solar cell. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, the transparent adhesive film, multiple cells arranged in a matrix form and welded with the metal wire, the transparent adhesive film, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down. In such a way, a solar cell module D51 is obtained.

Example 52

Example 52 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Metal Wire S
A copper wire is coated with an epoxy resin, in which the copper wire has a cross section of 0.04 mm², and the conductive adhesive has a thickness of 16 μm, so as to obtain the metal wire S.
The metal wire extends reciprocally under a strain from two clips at two ends of the copper wire, so as to form 20 parallel conductive wires. The distance between parallel adjacent conductive wires is 9.9 mm.
Then part of the conductive wires are arranged in the surface of the transparent film made of a PET film; then the conductive wires are heated, such that the contact portion of the transparent film and the conductive wires is softened or melted, so as to melt and fix the conductive wires and the transparent film together, and the metal wire comes out from the transparent film.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells are arranged in a matrix form (six rows and ten columns). In two adjacent cells in the same row, the transparent film connected with the conductive wires by melting is disposed on a front surface of a first cell, and the secondary grid lines contact with the conductive wires. The other conductive wires which are welded extend onto a back surface of a second cell to be connected with the back electrodes on the back surface of the second cell.
Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell faces the front adhesive layer 20, and the back surface of the cell faces the back adhesive layer 40, and finally they are laminated in a laminator so as to obtain the solar cell module A52.

Example 53

The solar cell module is manufactured according to the method in Example 51, but the difference compared with Example 51 lies in that a short grid line 33 (silver, 0.1 mm in width) is disposed on the secondary grid line of the shiny surface of the cell 31, and is perpendicular to the secondary grid line for connecting part of the secondary grid line at the edge of the shiny surface of the cell with the conductive wire, as shown in FIG. 12, so as to obtain a solar cell module A53.

Example 54

The solar cell module is manufactured according to the method in Example 51, but the difference compared with Example 51 lies in that the cells of six columns and six rows are connected in such a manner that in two adjacent rows of cells, the conductive wires extends from a shiny surface of a cell at an end of the a^throw (a≧1) to form electrical connection with a back surface of a cell at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows of cells are arranged in perpendicular to the conductive wires for connecting the adjacent cells in the two rows. In such a way, the solar cell module A4 is obtained.

Testing Example 51

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes;
(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 5.

	TABLE 5

	Solar cell module

	A51	D51	A52	A53	A54

It can be indicated from Table 5 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

Example 61

Example 61 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing Conductive Wires
An alloy layer of Sn40%-Bi55%-Pb5% (melting point: 125° C.) is attached to a surface of a copper wire, in which the copper wire has a cross section of 0.04 mm², and the alloy layer has a thickness of 16 μm. Hence, the conductive wires are obtained.
The conductive wires extend reciprocally, and the metal wire extends reciprocally under a strain from two clips at two ends thereof, so as to form 15 parallel conductive wires. The distance between parallel adjacent conductive wires is 9.9 mm.
Then part of the conductive wires are arranged in the surface of the longitudinal adhesive tape 61 of the transparent film frame 60 which is made of a transparent PET film, and has the longitudinal adhesive tape 61 and the transverse adhesive tape 62; then the conductive wires are heated, such that the contact portion of the transparent film and the conductive wires is softened or melted, so as to melt and fix the conductive wires and the transparent film together, and the metal wire comes out from the transparent film.
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1650×1000×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
60 cells are arranged in a matrix form (six rows and ten columns). In two adjacent cells in the same row, the transparent film connected with the conductive wires by melting is disposed on a front surface of a first cell, and the secondary grid lines contact with the conductive wires. The other conductive wires which are welded extend onto a back surface of a second cell to be connected with the back electrodes on the back surface of the second cell.
Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer 20, and the back surface of the cell 31 faces the back adhesive layer 40, and finally they are laminated in a laminator so as to obtain the solar cell module A61.

Comparison Example 61

The difference of Comparison example 61 and Example 61 lies in that the cells 31 are arranged in a matrix form. 15 metal wires connected in series are stuck on the transparent adhesive film, and then stuck on the solar cell. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, the transparent adhesive film, multiple cells arranged in a matrix form and welded with the metal wire, the transparent adhesive film, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down. In such a way, a solar cell module D61 is obtained.

Example 62

The solar cell module is manufactured according to the method in Example 61, but the difference compared with Example 61 lies in that a short grid line 33 (silver, 0.1 mm in width) is disposed on the secondary grid line of the shiny surface of the cell 31, and is perpendicular to the secondary grid line for connecting part of the secondary grid line at the edge of the shiny surface of the cell with the conductive wire, as shown in FIG. 12, so as to obtain a solar cell module A62.

Example 63

The solar cell module is manufactured according to the method in Example 61, but the difference compared with Example 61 lies in that the cells of six columns and six rows are connected in such a manner that in two adjacent rows of cells, the conductive wires extends from a shiny surface of a cell at an end of the a^throw (a≧1) to form electrical connection with a back surface of a cell at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows of cells are arranged in perpendicular to the conductive wires for connecting the adjacent cells in the two rows. In such a way, the solar cell module A63 is obtained.

Testing Example 61

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes;
(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions (STC): 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 6.

	TABLE 6

	Solar cell module

	A61	D61	A62	A63

It can be indicated from Table 6 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.

Example 71

Example 71 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing Conductive Wires
A copper wire is used, and the cross section of the copper wire is 0.04 mm².
(2) Manufacturing a Solar Cell Module 100
A POE adhesive layer in 1630×980×0.5 mm is provided (melting point: 65° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent secondary grid lines is 1.7 mm. An alloy layer of Sn40%-Bi55%-Pb5% coats the portion where each secondary grid line is needs to be connected with the conductive wire, by screen printing. The alloy layer has a thickness of 10 μm, a width of 60 μm, and a length of 0.4 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in a longitudinal direction, and the distance between the adjacent back electrodes is 31 mm.
The cells 31 are arranged in a matrix form. In two adjacent cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under a strain. The metal wire extends reciprocally when its two ends are strained by two clips, so as to form 15 parallel conductive wires. The secondary grid lines of a first cell 31 are welded with the conductive wires, and the back electrodes of a second cell 31 are welded with the conductive wires, at 160° C. of the welding temperature. The distance between parallel adjacent conductive wires is 9.9 mm. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer, and the back surface of the cell 31 faces the back adhesive layer, and finally they are laminated in a laminator so as to obtain the solar cell module A71.

Example 72

Example 72 is used to illustrate the solar cell module 100 according to the present disclosure and the manufacturing method thereof.
(1) Manufacturing a Primary Grid Line
A copper wire is used, and the cross section of the copper wire is 0.04 mm².
(2) Manufacturing a Solar Cell Module
A EVA adhesive layer in 1630×980×0.5 mm is provided (melting point: 60° C.), and a glass plate in 1633×985×3 mm and a polycrystalline silicon cell 31 in 156×156×0.21 mm are provided correspondingly. The cell 31 has 91 secondary grid lines (silver, 60 μm in width, 9 μm in thickness), each of which substantially runs through the cell 31 in a longitudinal direction, and the distance between the two adjacent secondary grid lines is 1.7 mm. The cell 31 has five back electrodes (tin, 1.5 mm in width, 10 μm in thickness) on its back surface. Each back electrode substantially runs through the cell 31 in the longitudinal direction, and the distance between the two adjacent back electrodes is 31 mm.
The cells 31 are arranged in a matrix form. An epoxy resin conductive adhesive layer is disposed at a portion where each secondary grid line needs to be connected with the conductive wire, by screen printing. The epoxy resin conductive adhesive layer has a thickness of 5 μm, a width of 30 μm, and a length of 0.6 mm. In two adjacent cells 31, the metal wire extends reciprocally between a front surface of a first cell 31 and a back surface of a second cell 31 under a strain, so as to form 20 parallel conductive wires. The secondary grid lines of the first cell 31 are welded with the conductive wires, and the back electrodes of the second cell 31 are welded with the conductive wires. The distance between parallel adjacent conductive wires is 7 mm. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the front surface of the cell 31 faces the front adhesive layer, and the back surface of the cell 31 faces the back adhesive layer. Finally, they are laminated in a laminator so as to obtain a solar cell module A72.

Example 73

The difference between Example 73 and Example 71 lies in that the cells 31 are arranged in a matrix form, and in two adjacent cells, each of the fifteen parallel metal wires, by wiredrawing, is strained by the clips at its ends to flatten the cells. The tension of the clips is 2N. An alloy layer of Sn40%-Bi55%-Pb5% is disposed at the portion where the secondary grid line on the front surface of the cell 31 contacts the metal wire, by screen printing. The alloy layer has a thickness of 15 μm, a width of 100 μm, and a length of 0.8 mm. Each of the fifteen parallel metal wires is welded with secondary grid lines on a front surface of a first cell 31 respectively, and welded with back electrodes on a back surface of a second cell 31. The distance between the parallel adjacent conductive wires is 9.9 mm. In such a way, a solar cell module A73 is obtained.

Example 74

The difference between Example 74 and Example 71 lies in that the cells 31 are arranged in a matrix form, and in two adjacent cells, each of the fifteen parallel metal wires, by wiredrawing, is strained by the clips at its ends to flatten the cells. The tension of the clips is 2N. An epoxy resin conductive adhesive layer is disposed at the portion where the secondary grid line on the front surface of the cell 31 contacts the metal wire, by screen printing. The alloy layer has a thickness of 3 μm, a width of 80 μm, and a length of 1 mm. Each of the fifteen parallel metal wires is welded with secondary grid lines on a front surface of a first cell 31 respectively, and welded with back electrodes on a back surface of a second cell 31. The distance between the parallel adjacent conductive wires is 9.9 mm. In such a way, a solar cell module A74 is obtained.

Comparison Example 71

The difference between Comparison example 71 and Example 71 lies in that the cells are arranged in a matrix form; the fifteen metal wires connected in series are pasted on the transparent film, and then pasted on the cells. In two adjacent cells, the metal wire connects a front surface of a first cell and a back surface of a second cell. Then, an upper glass plate, an upper POE adhesive layer, multiple cells arranged in a matrix form and welded with the metal wire, a lower POE adhesive layer and a lower glass plate are superposed sequentially from up to down, in which the shiny surface of the cell 31 faces the front adhesive layer, and the shady surface of the cell 31 faces the back adhesive layer. Finally, they are laminated in a laminator so as to obtain a solar cell module D72.

Example 75

The solar cell module is manufactured according to the method in Example 72, but the difference compared with Example 72 lies in that short grid lines 33 (silver, 0.1 mm in width) are disposed on the secondary grid lines of the shiny surface of the cell 31, and are perpendicular to the secondary grid lines for connecting part of the secondary grid lines at the edges of the shiny surface of the cell 31 with the conductive wires, as shown in FIG. 12, so as to obtain a solar cell module A75.

Example 76

The solar cell module is manufactured according to the method in Example 72, but the difference compared with Example 72 lies in that the cells 31 of six columns and six rows are connected in such a manner that in two adjacent rows of cells, the conductive wires extend from a shiny surface of a cell at an end of the a^throw (a≧1) to form electrical connection with a back surface of a cell 31 at an adjacent end of the (a+1)^throw, so as to connect the two adjacent rows of cells. The conductive wires for connecting the two adjacent rows of cells 31 are arranged in perpendicular to the conductive wires for connecting the adjacent cells 31 in the two rows. In such a way, the solar cell module A76 is obtained.

Testing Example 71

(1) Whether the metal wire in the solar cell module drifts is observed with the naked eyes;
(2) According to the method disclosed in IEC904-1, the solar cell modules manufactured in the above examples and the comparison example are tested with a single flash simulator under standard test conditions: 1000 W/m²of light intensity, AM1.5 spectrum, and 25° C. The photoelectric conversion efficiency of each cell is recorded. The testing result is shown in Table 7.

TABLE 7

Solar cell module	A1	A2	A3	A4	D1	A5	A6

Metal wire	no	no	no	no	Slightly	no	no
drifting
phenomenon
Photoelectric	16.70%	17.10%	16.80%	16.80%	15.50%	17.20%	17.05%
conversion
efficiency
Series	445	440	448	451	498	427	445
resistance
(mΩ)
Fill factor	0.783	0.792	0.781	0.779	0.764	0.793	0.79
Open-circuit	37.75	37.84	37.81	37.84	37.44	37.9	37.71
voltage (V)
Short-circuit	9.085	9.179	9.154	9.166	8.712	9.198	9.206
current (A)
Working	31.34	31.9	31.69	31.54	30.49	31.97	31.84
voltage (V)
Working	8.571	8.622	8.53	8.568	8.176	8.651	8.611
current (A)
Power (W)	268.6	275.1	270.3	270.2	249.3	276.6	274.2

It can be indicated from Table 1 that for the solar cell module according to the embodiments of the present disclosure, the metal wire will not drift, and higher photoelectric conversion efficiency can be obtained.
In the specification, it is to be understood that terms such as “central,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” and “counterclockwise” should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the present disclosure be constructed or operated in a particular orientation.
In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply relative importance or significance or to imply the number of indicated technical features. Thus, the feature defined with “first” and “second” may comprise one or more of this feature. In the description of the present disclosure, “a plurality of” means two or more than two, unless specified otherwise.
In the present disclosure, unless specified or limited otherwise, a structure in which a first feature is “on” or “below” a second feature may include an embodiment in which the first feature is in direct contact with the second feature, and may also include an embodiment in which the first feature and the second feature are not in direct contact with each other, but are contacted via an additional feature formed therebetween. Furthermore, a first feature “on,” “above,” or “on top of” a second feature may include an embodiment in which the first feature is right or obliquely “on,” “above,” or “on top of” the second feature, or just means that the first feature is at a height higher than that of the second feature; while a first feature “below,” “under,” or “on bottom of” a second feature may include an embodiment in which the first feature is right or obliquely “below,” “under,” or “on bottom of” the second feature, or just means that the first feature is at a height lower than that of the second feature.
Reference throughout this specification to “an embodiment,” “some embodiments,” or “some examples” means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, these terms throughout this specification do not necessarily refer to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
Although embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations can be made in the embodiments without departing from the scope of the present disclosure.

Claims

1-21. (canceled)

22. A solar cell module, comprising an upper cover plate, a front adhesive layer, a cell, a back adhesive layer and a back plate superposed in sequence, a secondary grid line being disposed on the cell, a conductive wire comprising a metal wire being disposed between the front adhesive layer and a front surface of the cell, a welding layer disposed on a welding position where the conductive wire and the secondary grid line are welded, the welding layer being an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, in which an amount of Bi is 15 to 60 weight percent.

23. The solar cell module according to claim 22, wherein based on the total weight of the alloy, there are 15 to 60 weight percent of Bi, 30 to 75 weight percent of Sn, 0 to 20 weight percent of Cu, 0 to 40 weight percent of In, 0 to 3 weight percent of Ag, 0 to 20 weight percent of Sb, 0 to 10 weight percent of Pb, and 0 to 20 weight percent of Zn.

24. The solar cell module according to claim 23, wherein the alloy is at least one selected from 50% Sn-48% Bi-1.5% Ag-0.5% Cu, 58% Bi-42% Sn, and 65% Sn-20% Bi-10% Pb-5% Zn.

25. The solar cell module according to claim 22, wherein the welding layer coats the metal wire.

26. The solar cell module according to claim 25, wherein the welding layer has a thickness of 1 to 100 μm, and the metal wire has a cross section of 0.01 to 0.5 mm².

27. The solar cell module according to claim 22, wherein there are multiple cells to constitute a cell array, adjacent cells connected by the conductive wires; the metal wire extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell.

28. The solar cell module according to claim 27, wherein the metal wire extends reciprocally between a front surface of the first cell and a back surface of the second cell.

29. (canceled)

30. The solar cell module according to claim 27, wherein the conductive wires are formed by reciprocally winding a metal wire.

31. The solar cell module according to claim 30, wherein the metal wire extends reciprocally for 10 to 60 times.

32. (canceled)

33. The solar cell module according to claim 27, wherein the two adjacent conductive wires form a U-shape structure or a V-shape structure.

34. The solar cell module according to claim 22, wherein the cells are arranged in an n×m matrix form, n representing a column, and m representing a row;

in a row of cells, the metal wire extends reciprocally between a surface of a first cell and a surface of a second cell adjacent to the first cell; in two adjacent rows of cells, the metal wire extends reciprocally between a surface of a cell in a ath row and a surface of a cell in a (a+1)th row, and m−1≧a≧1.

35. The solar cell module according to claim 34, wherein in two adjacent rows of cells, the metal wire extends reciprocally between a surface of a cell at an end of the ath row and a surface of a cell at an end of the (a+1)th row, the end of the ath row and the end of the (a+1)th row located at the same side of the matrix form.

36. The solar cell module according to claim 35, wherein in a row of cells, the metal wire extends reciprocally between a front surface of the first cell and a back surface of the second cell adjacent to the first cell;

in two adjacent rows of cells, the metal wire extends reciprocally between a front surface of a cell at the end of the ath row and a back surface of a cell at the end of the (a+1)th row, to connect the two adjacent rows of cells in series.

37. The solar cell module according to claim 34, wherein one metal wire extends reciprocally between adjacent cells in a row; and another metal wire extends reciprocally between cells in adjacent rows.

38. The solar cell module according to claim 22, wherein the secondary grid line has a width of 40 to 80 μm and a thickness of 5 to 20 μm; there are 50 to 120 secondary grid lines, a distance between adjacent secondary grid lines ranging from 0.5 to 3 mm.

39. The solar cell module according to claim 22, wherein the conductive wires are formed by a plurality of metal wires arranged parallel to and spaced from each other.

40. A method for manufacturing a solar cell module, comprising:

welding a conductive wire comprising a metal wire with a secondary grid line of a cell via a welding layer disposed in a position where the conductive wire and the secondary grid line are welded, in which the welding layer is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, and an amount of Bi is 15 to 60 weight percent;

superposing an upper cover plate, a front adhesive layer, the cell, a back adhesive layer and a back plate in sequence, such that a front surface of the cell faces the front adhesive layer, a back surface thereof facing the back adhesive layer; and

laminating the superposed layers to obtain the solar cell module.

41-42. (canceled)

43. The method according to claim 40, wherein the conductive wire and the secondary grid line are welded before or after they are superposed.

44. The method according to claim 40, wherein the conductive wire and the secondary grid line are welded when or after they are laminated.

45-53. (canceled)

54. A solar cell unit, comprising a cell and a conductive wire, in which the cell includes a cell substrate and a secondary grid line disposed on a front surface of a cell substrate; the conductive wire is constituted by a metal wire and welded with the secondary grid line; a welding layer is disposed on a position where the conductive wire and the secondary grid line are welded; the welding layer is an alloy containing Sn, Bi and at least one of Cu, In, Ag, Sb, Pb and Zn, an amount of Bi being 15 to 60 weight percent.

55-243. (canceled)