JP7713303B2 - Electrochemical cell and method for manufacturing the same - Google Patents

Description

The present invention relates to an electrochemical cell and a method for manufacturing an electrochemical cell.

Electrochemical cells such as lithium-ion secondary batteries and electrochemical capacitors have traditionally been widely used as power sources for small devices such as wristwatches, smart watches, smartphones, headsets, wearable devices, and hearing aids.
In recent years, there has been an increasing demand for smaller and thinner electrochemical cells of this type. One reason for this is that, with the advancement of performance due to the miniaturization and reduced power consumption of ICs (integrated circuits) in various electronic devices in which electrochemical cells are implemented, electronic devices equipped with unprecedented high-spec functions have begun to be proposed.

In this type of electrochemical cell, for example, a metal case or a laminate film is known as an exterior body for housing the electrode assembly therein.
The metal case, for example, comprises a cylindrical case body with a bottom and a sealing case that seals the opening of the case body by crimping or the like via a gasket, and is often configured as a coin shape, button shape, cylindrical shape, etc. On the other hand, when a laminate film is used as the exterior body, it is possible to increase the degree of freedom in shape, which can easily lead to miniaturization and increased capacity of the electrochemical cell itself.

Various structures are known for the electrode body, one of which is a wound structure formed by winding a positive electrode and a negative electrode flat with a separator between them. For example, the following Patent Document 1 discloses a secondary battery having an electrode body in which the positive electrode and the negative electrode are each formed in a strip shape with multiple laminated surfaces connected by connecting pieces, and the positive electrode and the negative electrode are wound flat so that each connecting piece is folded back, so that the laminated surfaces of the positive electrode and the laminated surfaces of the negative electrode are alternately stacked with a separator between them.

WO 02/13305

In a secondary battery having the above-mentioned conventional wound-type electrode body, for example, in order to ensure a predetermined battery capacity, it is necessary that each laminated surface of the positive electrode and each laminated surface of the negative electrode are precisely arranged to face each other via a separator.
However, in the above-mentioned secondary battery, when the electrode body is wound, the position of the negative electrode may be shifted relative to the positive electrode, which may cause a so-called misalignment. In this case, it becomes difficult to wind the positive electrode and the negative electrode in a state where the respective lamination surfaces of the positive electrode and the respective lamination surfaces of the negative electrode are precisely opposed to each other via the separator. This may lead to a decrease in operational reliability, and there is room for improvement.

The present invention was made in consideration of these circumstances, and its purpose is to provide an electrochemical cell having an electrode assembly with improved operational reliability, in which the positive and negative electrodes can be wound with the separator in between while maintaining an appropriate relative positional relationship, and a method for manufacturing the electrochemical cell.

(1) The electrochemical cell according to the present invention comprises an electrode body having a separator, a positive electrode, and a negative electrode, the positive electrode and the negative electrode being stacked with the separator sandwiched therebetween by being wound, and an exterior body that houses the electrode body, and at least one of the positive electrode and the negative electrode is positioned relative to the separator at the start of winding by a positioning portion.

According to the electrochemical cell of the present invention, the positioning portion can be used to position the relative position of at least one of the positive electrode and the negative electrode at the start of winding with respect to the separator. Therefore, when the positive electrode and the negative electrode that are stacked on each other with the separator sandwiched between them are wound to form an electrode body, it is possible to suppress the occurrence of so-called winding misalignment, in which the relative positional relationship between the positive electrode and the negative electrode is shifted with the separator sandwiched between them. This allows the positive electrode and the negative electrode to be stacked with precision with the separator sandwiched between them to form an electrode body, resulting in an electrochemical cell with improved operational reliability.

(2) The electrode body is wound flat so that the positive electrode and the negative electrode are alternately stacked with the separator in between, and the positive electrode comprises a plurality of positive electrode bodies arranged along the stacking direction of the electrode body and a plurality of positive electrode connection pieces that connect the plurality of positive electrode bodies to each other, and the negative electrode comprises a plurality of negative electrode bodies arranged along the stacking direction of the electrode body and a plurality of negative electrode connection pieces that connect the plurality of negative electrode bodies to each other, and the electrode body is wound in such a way that the positive electrode connection pieces and the negative electrode connection pieces are folded back, so that the positive electrode bodies and the negative electrode bodies are arranged in a state where they face each other alternately in the stacking direction with the separator in between. The positioning portion is provided between the first negative electrode body located at the start of winding among the plurality of negative electrode bodies and the separator, and includes a negative electrode positioning portion that positions the first negative electrode body with respect to the separator, and the negative electrode positioning portion is arranged so as to be positioned at least between the outer end of the first negative electrode body that faces the positive electrode connection piece across the separator, and the separator, and may lower the ionic conductivity of ions that move from the positive electrode connection piece through the separator toward the outer end during charging and discharging to be lower than the ionic conductivity of ions that move between the positive electrode body and the negative electrode body through the separator.

In this case, the negative electrode positioning portion can be used to position the first negative electrode main body relative to the separator, so that an electrode body can be formed in which a plurality of positive electrode main bodies and a plurality of negative electrode main bodies are alternately stacked in the stacking direction while being precisely positioned opposite each other with the separator in between, thereby making it possible to obtain an electrochemical cell with improved operational reliability.
In addition, the negative electrode positioning portion is arranged so as to be located at least between the outer end of the first negative electrode body and the separator, so that it is arranged as if to protect the negative electrode current collector exposed to the outside at the outer end. The negative electrode positioning portion plays a role in reducing the ionic conductivity of ions moving from the positive electrode connection piece toward the outer end through the separator, compared to the ionic conductivity of ions (e.g., lithium ions, etc.) moving between the positive electrode body and the negative electrode body through the separator during charging and discharging. Therefore, it is possible to suppress the movement of ions to the part where the negative electrode current collector is exposed during charging and discharging, and it is possible to make it difficult to cause inconveniences such as ions being precipitated in a needle-like shape on the negative electrode current collector. Therefore, this also makes it possible to further improve the operating reliability.

(3) The negative electrode positioning portion may be fixed to at least one of the first negative electrode body or the separator, may be an insulator that contacts the first negative electrode body and the separator, and may block an ion permeation hole formed in the separator.

In this case, since the negative electrode positioning portion is fixed to at least one of the first negative electrode body or the separator, the first negative electrode body can be reliably positioned relative to the separator, and misalignment between the positive electrode and the negative electrode during winding can be effectively prevented. Furthermore, since the negative electrode positioning portion is an insulator and can block the ion permeation holes by contacting the first negative electrode body and the separator, it is possible to effectively prevent ions from migrating from the positive electrode connection piece through the separator to the outer end of the first negative electrode body, i.e., the part where the negative electrode current collector is exposed, during charging and discharging. Therefore, the operating reliability can be further improved.

(4) The negative electrode positioning portion may be an insulating adhesive member that bonds the first negative electrode body and the separator to each other, and may also block ion permeation holes formed in the separator.

In this case, an adhesive member such as an insulating adhesive layer or insulating adhesive tape can be used as the negative electrode positioning portion, which is an insulator, making it easy to simplify the configuration and reduce costs. In particular, the adhesive member can block the ion permeation holes formed in the separator, so that during charging and discharging, the movement of ions from the positive electrode connection piece through the separator toward the outer end of the first negative electrode body, i.e., the part where the negative electrode current collector is exposed, can be effectively suppressed. Therefore, the operating reliability can be further improved.

(5) The negative electrode positioning portion may be a welded portion in which the first negative electrode body and the separator are welded to each other, and may block ion permeation holes formed in the separator by the welding.

In this case, the welded portion where the first negative electrode body and the separator are welded together functions as a negative electrode positioning portion, so that the first negative electrode body can be reliably positioned relative to the separator, and misalignment between the positive electrode and the negative electrode during winding can be effectively suppressed. Furthermore, the separator can be partially melted by welding the welded portion, reliably blocking the ion permeation holes. Therefore, during charging and discharging, it is possible to effectively suppress the movement of ions from the positive electrode connection piece through the separator toward the outer end of the first negative electrode body, i.e., the part where the negative electrode current collector is exposed. Therefore, the operating reliability can be further improved.

(6) The negative electrode positioning portion may be a separator welded portion formed by partially doubly welding a portion of the separator in advance, and may block ion permeable holes formed in the separator by the welding. The first negative electrode body may be positioned relative to the separator by contact of the outer end portion with the separator welded portion.

In this case, the separator welded portion, which is a portion of the separator that has been partially welded in advance, can function as a negative electrode positioning portion, and the first negative electrode body can be positioned relative to the separator by contacting the outer end with this separator welded portion when winding the electrode body. Therefore, it is possible to prevent misalignment between the positive electrode and the negative electrode when winding. Furthermore, it is possible to partially melt the separator by welding the separator welded portion, thereby reliably blocking the ion permeation holes. Therefore, it is possible to effectively prevent ions from moving from the positive electrode connection piece through the separator to the outer end of the first negative electrode body, i.e., the part where the negative electrode current collector is exposed, during charging and discharging. Therefore, it is possible to further improve the operating reliability.

(7) The negative electrode positioning portion may be an unwound portion in which a portion of the separator is pre-wound, and the first negative electrode body may be positioned relative to the separator by contact of the outer end portion with the unwound portion.

In this case, the empty wound portion, which is a portion of the separator that has been wound in advance, can function as a negative electrode positioning portion, and the first negative electrode body can be positioned relative to the separator by contacting the outer end with this empty wound portion when winding the electrode body. This makes it possible to prevent misalignment between the positive electrode and the negative electrode when winding. Furthermore, since it is possible to make it more difficult for ions to pass through by the amount of empty winding, it is possible to effectively prevent ions from moving from the positive electrode connection piece through the separator toward the outer end of the first negative electrode body, i.e., the part where the negative electrode current collector is exposed, during charging and discharging. This makes it possible to further improve operational reliability.

(8) The positioning portion may include a positive electrode positioning portion provided between the positive electrode and the separator, which positions a first positive electrode body located at the start of winding among the multiple positive electrode bodies relative to the separator.

In this case, the positive electrode positioning portion can be used to position the first positive electrode body relative to the separator, so that the first positive electrode body located at the start of winding the positive electrode and the first negative electrode located at the start of winding the negative electrode can be precisely aligned with the separator in between during winding. This makes it possible to more effectively prevent misalignment between the positive electrode and the negative electrode caused by the separator being sandwiched during winding.

(9) The exterior body may be formed of a laminate film having a metal layer and a resin layer covering both sides of the metal layer.

In this case, since the exterior body is formed from a laminate film having a metal layer and a resin layer, it can be a so-called laminate type electrochemical cell with excellent freedom of shape, and can be easily used for various applications. Furthermore, the high sealing properties make it easy to seal the electrode body, prevent the intrusion of dust, moisture, etc. from the outside, and make it easy to suppress the leakage of the contents inside the battery over a long period of time, resulting in an electrochemical cell with further improved operational reliability.

(10) The battery may include a support section housed inside the exterior body and arranged along the battery axis direction, and the electrode body is wound around the support section so that the positive electrode and the negative electrode are superimposed with the separator sandwiched therebetween, and the positioning section includes a fixing section that fixes the support section and the separator, and the positive electrode and the negative electrode are positioned on the support section based on the fixing section, thereby positioning the electrodes relative to the separator.

In this case, the electrode body is wound around the support part, and the positive electrode and the negative electrode are superimposed with the separator sandwiched therebetween, to form a wound electrode wound around the central axis of the support part. In particular, when the electrode body is wound using the support part, the support part and the separator can be fixed using the fixing part, and the separator can be positioned with respect to the support part. Therefore, when the electrode body is wound, the positive electrode and the negative electrode can be positioned on the support part with the fixing part as a reference, so that the relative positions with respect to the separator can be determined. Therefore, it is possible to suppress the occurrence of so-called winding misalignment, in which the relative positional relationship between the positive electrode and the negative electrode is shifted with the separator sandwiched therebetween. As a result, the electrode body can be formed by precisely superimposing the positive electrode and the negative electrode with the separator sandwiched therebetween, and an electrochemical cell with improved operating reliability can be obtained.
Furthermore, since the winding core used when winding the electrode body can be used as the support, after the electrode body is formed by winding, the electrode body together with the support can be housed inside the exterior body, which makes it possible to perform assembly work efficiently and leads to improved productivity.

(11) The exterior body includes a metal container body having a bottom wall portion and a peripheral wall portion and formed into a bottomed cylindrical shape, and a metal sealing plate welded to the container body so as to close the opening of the container body and accommodates the electrode body between the container body and the metal sealing plate, and a current collector plate at least a portion of which is exposed to the outside is welded to the sealing plate or the bottom wall portion via an insulating sealant, and the support portion supports the sealing plate by having a first end portion contact the current collector plate and a second end portion contact the sealing plate or the bottom wall portion, and one of the positive electrode and the negative electrode is conductive to the current collector plate and the other electrode is conductive to the container body.

In this case, since the exterior body is formed by the metallic container body and sealing plate, it can be a so-called metal can type electrochemical cell.
In particular, the support pillar is arranged so as to be sandwiched between the sealing plate and the bottom wall in the battery axial direction, the first end is in direct or indirect contact with the current collector plate, and the second end is in direct or indirect contact with the sealing plate or the bottom wall of the container body.
As a result, for example, when the first end of the support portion is in contact with the current collecting plate welded to the sealing plate via a sealant and the second end of the support portion is in contact with the bottom wall of the container body, the support portion can be used to support the sealing plate. In contrast, for example, even when the first end of the support portion is in contact with the current collecting plate welded to the bottom wall via a sealant and the second end of the support portion is in contact with the sealing plate, the support portion can be used to support the sealing plate.
In either case, the support portion can be used to support the sealing plate.

Therefore, even if the entire exterior body including the sealing plate is formed thin, unintended deformation such as bending of the sealing plate can be suppressed before welding the container body and the sealing plate. Therefore, welding work can be performed while suppressing misalignment of the sealing plate relative to the container body, improving work efficiency and leading to improved productivity. Furthermore, the container body and the sealing plate can be precisely welded appropriately, and reliable sealing can be obtained. Therefore, a high-quality electrochemical cell with high operational reliability can be obtained. In addition, since one of the positive and negative electrodes is conductive to the current collector plate and the other electrode is conductive to the container body, the current collector plate and the container body can be used as external connection terminals.

(12) A method for manufacturing an electrochemical cell according to the present invention includes an electrode body having positive and negative electrodes stacked on top of each other with a separator sandwiched therebetween, the electrode body being wound flat so that the positive and negative electrodes are alternately stacked with the separator sandwiched therebetween, and an exterior body that houses the electrode body, the positive electrode having a plurality of positive main bodies arranged along the stacking direction of the electrode body and a plurality of positive connection pieces that connect the plurality of positive main bodies to each other, and the negative electrode having a plurality of negative main bodies arranged along the stacking direction of the electrode body and a plurality of negative connection pieces that connect the plurality of negative main bodies to each other, and the method for manufacturing an electrochemical cell includes winding the positive connection pieces and the negative connection pieces so that the positive and negative main bodies are alternately stacked with the separator sandwiched therebetween, the positive and negative connection pieces being wound in a folded manner, The electrode body forming process includes forming the electrode body so that the electrodes are arranged facing each other, and during the electrode body forming process, a positioning process is performed in which a negative electrode positioning part is provided between a first negative electrode body located at the start of winding among the multiple negative electrode bodies and the separator, thereby positioning the first negative electrode body with respect to the separator, and during the positioning process, the negative electrode positioning part is provided so as to be positioned at least between the separator and an outer end of the first negative electrode body that faces the positive electrode connection piece across the separator, and the negative electrode positioning part reduces the ionic conductivity of ions that move from the positive electrode connection piece to the outer end through the separator to less than the ionic conductivity of ions that move between the positive electrode body and the negative electrode body through the separator.

According to the method for manufacturing an electrochemical cell of the present invention, the first negative electrode main body can be positioned relative to the separator using the negative electrode positioning part, so that it is possible to prevent the relative positional relationship between the positive electrode and the negative electrode across the separator from shifting, i.e., the occurrence of so-called winding misalignment, during the formation of the electrode body. Therefore, it is possible to form an electrode body in which multiple positive electrode main bodies and multiple negative electrode main bodies are alternately stacked in the stacking direction while being precisely positioned opposite each other across the separator, and it is possible to manufacture an electrochemical cell with improved operational reliability.
In addition, since the negative electrode positioning portion is disposed so as to be located at least between the outer end of the first negative electrode main body and the separator, the negative electrode current collector exposed to the outside at the outer end can be protected. Moreover, the negative electrode positioning portion plays a role in reducing the ionic conductivity of ions moving from the positive electrode connection piece toward the outer end through the separator, compared to the ionic conductivity of ions moving between the positive electrode main body and the negative electrode main body through the separator during charging and discharging. Therefore, it is possible to suppress the movement of ions to the exposed part of the negative electrode current collector during charging and discharging, and it is possible to make it difficult for inconveniences such as ions being precipitated in a needle-like shape on the negative electrode current collector to occur.

(13) An insulating adhesive material may be used as the negative electrode positioning part, and during the positioning process, the adhesive material may be applied to the outer end of the first negative electrode body or to the surface of the separator facing the outer end of the first negative electrode body, and then at least a portion of the applied adhesive material may be solidified or moistened, and the outer end of the first negative electrode body and the separator may be bonded to each other to perform positioning.

In this case, in addition to using an insulating adhesive material as the negative electrode positioning portion, at least a portion of the adhesive material after application is solidified or moderately moistened. This effectively reduces slippage between the first negative electrode body and the separator when they are brought into contact with each other. Therefore, in addition to the above-mentioned effects, it is possible to effectively suppress misalignment when winding the positive electrode and negative electrode that are stacked on top of each other with the separator sandwiched therebetween to form an electrode body, and it is possible to more efficiently manufacture an electrochemical cell with improved operational reliability.

According to the present invention, it is possible to wind the positive and negative electrodes with the separator sandwiched between them while maintaining an appropriate relative positional relationship, resulting in an electrochemical cell equipped with an electrode assembly with improved operational reliability.

1 is a perspective view showing a first embodiment of a secondary battery (electrochemical cell) according to the present invention. 2 is a longitudinal sectional view of the secondary battery taken along line AA shown in FIG. 1. FIG. 3 is a top view of the electrode body shown in FIG. 2 . 4 is a longitudinal cross-sectional view of the electrode body taken along line BB shown in FIG. 3. 3 is an enlarged longitudinal sectional view of the secondary battery of a portion surrounded by a virtual circle C shown in FIG. 2. 5 is an enlarged longitudinal sectional view of an electrode body in which a portion surrounded by a virtual circle D shown in FIG. 4 is enlarged. FIG. 5 is a development view of the positive electrode shown in FIG. 4 before being wound. FIG. 5 is a development view of the negative electrode shown in FIG. 4 before being wound. FIG. 9 is a diagram showing an example in which the positive electrode and the negative electrode shown in FIGS. 7 and 8 are started to be wound; FIG. 9 is a diagram showing another example in which the positive electrode and the negative electrode shown in FIGS. 7 and 8 are started to be wound. FIG. 9 is a diagram showing an example of a case where the positive electrode and the negative electrode shown in FIG. 7 and FIG. 8 are wound using a winding machine. FIG. 13 is a diagram showing an example of a case in which an outer end portion of an inner periphery side negative electrode body and a separator are combined using an adhesive. FIG. 11 is a diagram showing another example of a case in which an outer end portion of an inner periphery side negative electrode body and a separator are combined using an adhesive. FIG. 13 is a diagram showing an example of a case in which the outer end portion of the inner periphery side negative electrode body and the separator are combined by welding. FIG. 13 is a diagram showing an example of a case in which a part of the separator is welded in advance, and then the outer end portion of the inner periphery side negative electrode main body is assembled. FIG. 16 is a vertical cross-sectional view of an electrode assembly formed using the separator shown in FIG. 15 . FIG. 13 is a diagram showing an example of a case in which the outer end portion of the inner periphery side positive electrode main body and the separator are combined by welding. FIG. 18 is a diagram showing an example of a case where an outer end portion of an inner periphery side negative electrode main body is combined with the separator shown in FIG. 17 by using an adhesive. 13 is a longitudinal cross-sectional view of an electrode assembly in which the outer end of the inner periphery side negative electrode main body is combined with the separator by utilizing the empty wound portion of the separator. FIG. FIG. 13 is a perspective view showing a modified example of the secondary battery according to the present invention. FIG. 11 is a vertical cross-sectional view showing a modified example of the electrode body according to the present invention. FIG. 2 is a longitudinal sectional view showing a second embodiment of a secondary battery (electrochemical cell) according to the present invention. 23 is a longitudinal sectional view of the secondary battery taken along line EE shown in FIG. 22. 23 is a cross-sectional perspective view of the secondary battery taken along line EE shown in FIG. 22. FIG. 24 is a diagram showing one process step in winding the electrode body shown in FIG. 23 around a support pole, showing a state in which a separator has been fixed to the outer peripheral surface of the support pole. 26 is a diagram showing a state in which the support column is rotated from the state shown in FIG. 25 and the separator is wound around the support column first. FIG. 27 is a diagram showing a state in which the support portion is further rotated from the state shown in FIG. 26, and the negative electrode is wound around the support portion together with the separator in advance. FIG. FIG. 11 is a longitudinal sectional view showing a third embodiment of a secondary battery (electrochemical cell) according to the present invention. 29 is a diagram showing a state in which the negative electrode terminal tab of the negative electrode in the electrode body shown in FIG. 28 is connected to the outer peripheral surface of the support portion. 29 is a diagram showing a state in which the negative electrode terminal tab of the negative electrode and the separator in the electrode body shown in FIG. 28 are connected to the outer peripheral surface of the support portion. FIG. 29 is a diagram showing the state in which the negative electrode terminal tab of the negative electrode in the electrode body shown in FIG. 28 is inserted into the slit groove of the support column. FIG. 29 is a diagram showing a state in which the negative electrode terminal tab of the negative electrode in the electrode body shown in FIG. 28 is inserted into the support portion and the separator is connected to the outer peripheral surface of the support portion. FIG. 11 is a vertical cross-sectional view showing a modified example of the secondary battery of the third embodiment. FIG. 11 is a longitudinal sectional view showing a fourth embodiment of a secondary battery (electrochemical cell) according to the present invention.

First Embodiment
Hereinafter, a first embodiment of an electrochemical cell according to the present invention will be described with reference to the drawings. In this embodiment, a lithium ion secondary battery (hereinafter simply referred to as a secondary battery), which is a type of non-aqueous electrolyte secondary battery, will be taken as an example of the electrochemical cell. Furthermore, in this embodiment, a so-called laminate type secondary battery, in which the exterior body is formed of a laminate film, will be taken as an example.

As shown in Figs. 1 and 2, the secondary battery 1 of this embodiment is a so-called coin-type (button-type) battery, and mainly comprises an electrode body 2 having multiple electrodes, i.e., a positive electrode 10 and a negative electrode 20, stacked on top of each other in a stacking direction Z, and an exterior body 3 that houses the electrode body 2. Note that in each drawing, the electrode body 2 is appropriately simplified.

As shown in Figures 3 and 4, the electrode body 2 includes a positive electrode 10, a negative electrode 20, and a separator 30. The electrode body 2 is a laminated electrode with a wound structure in which the positive electrode 10 and the negative electrode 20 are stacked and wound flat with the separator 30 sandwiched between them. As a result, the positive electrode 10 and the negative electrode 20 are arranged in a state where they are alternately stacked in the stacking direction Z with the separator 30 sandwiched between them.

The electrode body 2 is formed so that its outer shape is circular in a plan view. However, the outer shape of the electrode body 2 is not limited to this case and may be other shapes, such as an ellipse, an oval shape, or a diamond shape, and may be changed as appropriate.
The structure of the electrode body 2 will be described in detail later.

In this embodiment, an example will be described in which the stacking direction Z is the vertical direction, that is, the positive electrode 10 and the negative electrode 20 are stacked in the vertical direction. Furthermore, the axis that passes through the center of the electrode body 2 and extends along the stacking direction Z is called the battery axis O1, and in a plan view seen from the battery axis O1 direction, the direction that intersects the battery axis O1 is called the radial direction, and the direction going around the battery axis O1 is called the circumferential direction.

(Exterior body)
As shown in Figs. 1, 2 and 5, the exterior body 3 is formed of a laminate film.
The exterior body 3 includes a first laminate member 40 and a second laminate member 50 that are stacked in the stacking direction Z with the electrode body 2 sandwiched therebetween. As a result, the exterior body 3 accommodates the electrode body 2 in a sealed state between the first laminate member 40 and the second laminate member 50. Note that an electrolyte solution (electrolyte solution) (not shown) is filled between the first laminate member 40 and the second laminate member 50.

The first laminate member 40 is a member that covers the electrode body 2 from above, and has a metal layer 41, and an inner resin layer 42 and an outer resin layer 43 that cover both sides of the metal layer 41. The inner resin layer 42 and the outer resin layer 43 are tightly bonded to both sides of the metal layer 41, for example by heat fusion or adhesion, via a bonding layer not shown. Note that in each drawing except for FIG. 5, the metal layer 41, the inner resin layer 42, and the outer resin layer 43 are not shown.

The metal layer 41 is formed from a metal material suitable for blocking outside air and water vapor, such as stainless steel or aluminum.
The inner resin layer 42 functions as an inner layer in the exterior body 3, and is formed using a thermoplastic resin such as polyolefin polyethylene or polypropylene. As the polyolefin, any of the following materials can be used: high-pressure low-density polyethylene (LDPE), low-pressure high-density polyethylene (HDPE), inflation polypropylene (IPP) film, non-oriented polypropylene (CPP) film, biaxially oriented polypropylene (OPP) film, linear short-chain branched polyethylene (L-LDPE, metallocene catalyst specification). In particular, polypropylene resin is preferable.
The outer resin layer 43 functions as an outer layer in the exterior body 3, and is formed using, for example, the above-mentioned polyolefin, polyester such as polyethylene terephthalate, nylon, or the like.

The first laminate member 40 includes a topped cylindrical storage portion 45 and a first sealing cylindrical portion 46, and is disposed coaxially with the battery axis O1. The storage portion 45 includes a cylindrical peripheral wall portion 47 that radially surrounds the electrode body 2 from the outside, and a top wall portion 48 that closes the upper end opening of the peripheral wall portion 47 and covers the electrode body 2 from above.
The first sealing cylinder portion 46 is formed in a cylindrical shape that radially surrounds the peripheral wall portion 47 from the outside. The lower end portion of the first sealing cylinder portion 46 is formed to be integrally connected to the lower end portion of the peripheral wall portion 47. In other words, the first sealing cylinder portion 46 is formed by folding back the peripheral wall portion 47 upward.

The second laminate member 50 is a member that covers the electrode body 2 from below, and has a metal layer 51, and an inner resin layer 52 and an outer resin layer 53 that cover both sides of the metal layer 51. The inner resin layer 52 and the outer resin layer 53 are tightly joined to both sides of the metal layer 51, for example, by heat fusion or adhesion, via a joining layer (not shown).
The materials and the like of the metal layer 51, the inner resin layer 52, and the outer resin layer 53 are similar to those of the metal layer 41, the inner resin layer 42, and the outer resin layer 43 in the first laminate member 40. Moreover, in each of the drawings except for Fig. 5, the metal layer 51, the inner resin layer 52, and the outer resin layer 53 are omitted from illustration.

The second laminate member 50 is formed in a bottomed cylindrical shape with a cylindrical second sealing tube portion 56 that further surrounds the first sealing tube portion 46 from the outside in the radial direction, and a bottom wall portion 57 that closes the lower end opening of the second sealing tube portion 56 and covers the electrode body 2 from below, and is arranged coaxially with the battery axis O1.

The first laminate member 40 and the second laminate member 50 configured as described above are combined in a state in which the electrode body 2 and the electrolyte solution are sealed inside by heat welding the first sealing tube portion 46 and the second sealing tube portion 56 to each other. Specifically, the inner resin layer 42 in the first sealing tube portion 46 and the inner resin layer 52 in the second sealing tube portion 56 are heat welded to each other.

Furthermore, as shown in FIG. 2 , the secondary battery 1 of this embodiment includes a first electrode plate 60 and a second electrode plate 61, a first electrode terminal plate 62 and a second electrode terminal plate 63, a first sealant film 64 and a second sealant film 65.
The first electrode plate 60 , the second electrode plate 61 , the first electrode terminal plate 62 , the second electrode terminal plate 63 , the first sealant film 64 and the second sealant film 65 are housed inside the exterior body 3 together with the electrode body 2 .

The first electrode plate 60, the first electrode terminal plate 62, and the first sealant film 64 are disposed between the electrode body 2 and the top wall portion 48 of the first laminate member 40. The second electrode plate 61, the second electrode terminal plate 63, and the second sealant film 65 are disposed between the electrode body 2 and the bottom wall portion 57 of the second laminate member 50.

The first electrode plate 60 is formed, for example, in a circular shape when viewed from above, and is electrically connected to the positive electrode 10 of the electrode body 2. The first electrode plate 60 is formed, for example, from a metal material such as aluminum or stainless steel, with a smaller diameter than the electrode body 2, and is disposed coaxially with the battery axis O1.
A positive electrode terminal tab 15 (described later) of the positive electrode 10 is joined to the lower surface of the first electrode plate 60 by, for example, ultrasonic welding. In this way, the first electrode plate 60 is electrically connected to the positive electrode 10.

The first electrode terminal plate 62 is made of a metal material such as nickel and has a circular shape in plan view with a diameter smaller than that of the first electrode plate 60, and is disposed so as to overlap the upper surface of the first electrode plate 60 facing the first laminate member 40. The first electrode terminal plate 62 is integrally joined to the upper surface of the first electrode plate 60 by, for example, ultrasonic welding or resistance welding.
This electrically connects the first electrode plate 60 and the first electrode terminal plate 62. The first electrode terminal plate 62 may be a metal material such as copper with nickel formed on the surface. In this case, the first electrode terminal plate 62 can be produced by, for example, nickel plating. Furthermore, the first electrode terminal plate 62 may be formed partially on the first electrode plate 60 by nickel plating, thermal spraying, or the like.
The first electrode terminal plate 62 functions as an external connection terminal for the positive electrode 10 .

A first through hole 48a is formed in the top wall portion 48 of the first laminate member 40, exposing the first electrode terminal plate 62 to the outside. The first through hole 48a is formed in a circular shape in a plan view so as to penetrate vertically through the center of the top wall portion 48, and is formed coaxially with the battery axis O1.

The first sealant film 64 is formed in a ring shape surrounding the first electrode terminal plate 62 from the radially outside, and is arranged coaxially with the battery axis O1 between the first electrode terminal plate 62 and the top wall portion 48 of the first laminate member 40 while surrounding the first electrode terminal plate 62.
The first sealant film 64 is heat-welded to the inner resin layer 42 of the top wall portion 48 of the first laminate member 40 and to the upper surface of the first electrode plate 60. As a result, the first electrode plate 60 is heat-welded to the top wall portion 48 of the first laminate member 40 via the first sealant film 64.

The first sealant film 64 is made of a thermoplastic resin such as a polyolefin such as polyethylene or polypropylene, or a copolymer of multiple types of polyolefins, and contains a polypropylene nonwoven fabric. It is also possible to form the first sealant film 64 using a composite material of these thermoplastic resins and nonwoven fabric.

Since the first electrode plate 60, the first electrode terminal plate 62, and the first sealant film 64 are formed as described above, the entire surface of the first electrode terminal plate 62 is exposed upward through the first through hole 48a.

The second electrode plate 61, the second electrode terminal plate 63, and the second sealant film 65 are formed and arranged in the same manner as the first electrode plate 60, the first electrode terminal plate 62, and the first sealant film 64 described above.

The second electrode plate 61 is formed in a circular shape in a plan view, and is electrically connected to the negative electrode 20 of the electrode body 2. The second electrode plate 61 is formed with a smaller diameter than the electrode body 2 from a metal material such as copper, and is arranged coaxially with the battery axis O1. A negative electrode terminal tab 25 (described later) of the negative electrode 20 is joined to the upper surface of the second electrode plate 61 by, for example, ultrasonic welding. This electrically connects the second electrode plate 61 to the negative electrode 20.

The second electrode terminal plate 63 is made of a metal material such as nickel and is circular in plan view with a smaller diameter than the second electrode plate 61, and is disposed on the lower surface of the second electrode plate 61 facing the second laminate member 50. The second electrode terminal plate 63 is integrally joined to the lower surface of the second electrode plate 61 by, for example, ultrasonic welding or resistance welding.
This electrically connects the second electrode plate 61 and the second electrode terminal plate 63. The second electrode terminal plate 63 may be a metal material such as copper with nickel formed on the surface. In this case, the second electrode terminal plate 63 can be produced by, for example, nickel plating. Furthermore, the second electrode terminal plate 63 may be formed partially on the second electrode plate 61 by nickel plating, thermal spraying, or the like.
The second electrode terminal plate 63 functions as an external connection terminal for the negative electrode.

A second through hole 57a is formed in the bottom wall portion 57 of the second laminate member 50, exposing the second electrode terminal plate 63 to the outside. The second through hole 57a is formed in a circular shape in a plan view so as to penetrate vertically through the center of the bottom wall portion 57, and is formed coaxially with the battery axis O1.

The second sealant film 65 is formed in a ring shape surrounding the second electrode terminal plate 63 from the radially outside, and is arranged coaxially with the battery axis O1 between the second electrode terminal plate 63 and the bottom wall portion 57 of the second laminate member 50 while surrounding the second electrode terminal plate 63.
The second sealant film 65 is heat-welded to the inner resin layer 52 of the bottom wall portion 57 of the second laminate member 50 and to the lower surface of the second electrode plate 61. As a result, the second electrode plate 61 is heat-welded to the bottom wall portion 57 of the second laminate member 50 via the second sealant film 65.

The second sealant film 65, like the first sealant film 64, is made of a thermoplastic resin such as a polyolefin such as polyethylene or polypropylene, or a copolymer of multiple types of polyolefins, and contains a polypropylene nonwoven fabric. It is also possible to form the second sealant film 65 using a composite material of these thermoplastic resins and nonwoven fabrics.

Since the second electrode plate 61, the second electrode terminal plate 63, and the second sealant film 65 are formed as described above, the entire surface of the second electrode terminal plate 63 is exposed downward through the second through hole 57a.

(electrode body)
The electrode body 2 will now be described in detail.
3, 4, and 6, the electrode body 2 is formed by winding a positive electrode 10 and a negative electrode 20 flat in a state where they are stacked with a separator 30 interposed therebetween. Thus, the positive electrode 10 and the negative electrode 20 are wound together with the separator 30 about a winding axis O2.
As shown in FIG. 3, the electrode body 2 is wound around a winding axis O2 that intersects with the battery axis O1, and is housed inside the exterior body 3 while maintaining this state.

As shown in FIG. 7, the positive electrode 10 is formed in the form of a single sheet including a positive electrode collector 11 (positive electrode collector foil) formed in a band shape extending along a first direction L1 in an unfolded state before being wound, and a positive electrode active material layer 12 (see FIG. 6) formed by coating or the like on both sides of the positive electrode collector 11.
In addition, the positive electrode active material layer 12 is omitted in FIG.

The positive electrode current collector 11 is formed in the form of a thin sheet made of a metal material such as aluminum or stainless steel. The positive electrode active material layer 12 is formed on both sides of the positive electrode current collector 11 except for a positive electrode terminal tab 15, which will be described later. The positive electrode active material layer 12 contains a positive electrode active material, a conductive assistant, a binder, a thickener, and the like.
As the positive electrode active material, for example, lithium cobalt oxide (LCO), lithium nickel-manganese-cobalt oxide (NMC), etc. can be used.

Examples of conductive additives include carbon black, carbon materials, metal fibers, and metal powders. Examples of binders include resin materials such as polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). Examples of thickeners include resin materials such as carboxymethyl cellulose (CMC).

The positive electrode 10 includes a plurality of positive electrode bodies 13 and a plurality of positive electrode connection pieces 14 .
The positive electrode bodies 13 are formed in a disk shape in the expanded state of the positive electrode 10, and are arranged at intervals so as to be aligned in a line in the first direction L1. In the illustrated example, the number of positive electrode bodies 13 is 10. However, the number of positive electrode bodies 13 is not limited to 10 and may be changed as appropriate.
The positive electrode body 13 is a portion that is overlapped with a negative electrode body 23 (described later) so as to face the negative electrode body 23 in the stacking direction Z with a separator 30 interposed therebetween.

In the expanded state of the positive electrode 10, the positive electrode connecting pieces 14 are disposed between the positive electrode bodies 13 adjacent to each other in the first direction L1, and connect the adjacent positive electrode bodies 13 to each other. Therefore, in the illustrated example, the number of positive electrode connecting pieces 14 is nine.
The positive electrode connection piece 14 is a portion that is folded back at the side of the electrode body 2 by winding. In addition, the positive electrode connection piece 14 is formed so that the width in a second direction L2 perpendicular to the first direction L1 in a plan view is shorter than the width of the positive electrode main body 13 in the second direction L2.
In particular, the dimension of each positive electrode connection piece 14 along the first direction L1 is larger for the positive electrode connection piece 14 disposed closer to the outer periphery of the electrode body 2 in the wound state. As a result, the distance between adjacent positive electrode bodies 13 in the first direction L1 in the developed state is larger for the positive electrode connection pieces 14 disposed closer to the outer periphery in the wound state.

Of the multiple positive electrode bodies 13, the positive electrode body 13 located on the innermost side of the electrode body 2 in the wound state is referred to as the inner periphery side positive electrode body (first positive electrode body according to the present invention) 13A, and the positive electrode body 13 located on the outermost side is referred to as the outer periphery side positive electrode body 13B. Therefore, the inner periphery side positive electrode body 13A corresponds to the positive electrode body 13 located at the start of winding.

Furthermore, a positive electrode terminal tab 15 is formed on the outer peripheral positive electrode body 13B so as to extend further outward in the first direction L1 in the developed state of the positive electrode 10. As described above, the positive electrode terminal tab 15 does not have the positive electrode active material layer 12 formed on either side thereof, and is electrically connected to the lower surface of the first electrode plate 60.
The positive electrode terminal tab 15 is electrically connected to the first electrode plate 60 in a folded state with the connection portion with the outer peripheral positive electrode main body 13B as a base point.

As shown in FIG. 8, the negative electrode 20 is formed in the shape of a single sheet including a negative electrode current collector 21 (negative electrode current collector foil) formed in a band shape extending along a first direction L1 in an unfolded state before being wound, and a negative electrode active material layer 22 (see FIG. 6) formed by coating or the like on both sides of the negative electrode current collector 21.
In FIG. 8, the negative electrode active material layer 22 is omitted.

The negative electrode current collector 21 is formed in the form of a thin sheet from a metal material such as copper, nickel, or stainless steel. The negative electrode active material layer 22 is formed on both sides of the negative electrode current collector 21, excluding the negative electrode terminal tab 25 described below. This negative electrode active material layer 22 contains a negative electrode active material, a conductive additive, a binder, a thickener, etc., and is formed from a carbon material such as natural or artificial graphite.

Examples of conductive additives include carbon black, carbon materials, metal fibers, and metal powders. Examples of binders include resin materials such as polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), and polytetrafluoroethylene (PTFE). Examples of thickeners include resin materials such as carboxymethyl cellulose (CMC).

The negative electrode 20 includes a plurality of negative electrode bodies 23 and a plurality of negative electrode connection pieces 24 .
The negative electrode bodies 23 are formed in a disk shape similar to the positive electrode bodies 13 in the expanded state of the negative electrode 20, and are arranged at intervals so as to be aligned in a line in the first direction L1. In the illustrated example, the number of the negative electrode bodies 23 is 10, corresponding to the number of the positive electrode bodies 13. However, the number of the negative electrode bodies 23 is not limited to 10, and may be changed appropriately corresponding to the number of the positive electrode bodies 13.

In the deployed state of the negative electrode 20, the negative electrode connection pieces 24 are disposed between the negative electrode bodies 23 adjacent to each other in the first direction L1, and connect the adjacent negative electrode bodies 23 to each other. Therefore, in the illustrated example, the number of negative electrode connection pieces 24 is nine.
The negative electrode connection piece 24 is a portion that is folded back by winding at a side portion of the electrode body 2. In addition, the negative electrode connection piece 24 is formed so that the width in a second direction L2 perpendicular to the first direction L1 in a plan view is shorter than the width of the negative electrode main body 23 in the second direction L2.

In particular, the dimension of each negative electrode connection piece 24 along the first direction L1 is larger for the negative electrode connection piece 24 located closer to the outer periphery of the electrode body 2 in the wound state. As a result, the distance between adjacent negative electrode bodies 23 in the first direction L1 in the unfolded state is larger the closer to the outer periphery in the wound state.

Of the multiple negative electrode bodies 23, the negative electrode body 23 located on the innermost side of the electrode body 2 in the wound state is referred to as the inner circumferential side negative electrode body (first negative electrode body according to the present invention) 23A, and the negative electrode body 23 located on the outermost side is referred to as the outer circumferential side negative electrode body 23B. Therefore, the inner circumferential side negative electrode body 23A corresponds to the negative electrode body 23 located at the start of winding.

Furthermore, a negative electrode terminal tab 25 is formed on the outer peripheral negative electrode body 23B so as to extend further outward in the first direction L1 in the developed state of the negative electrode 20. As described above, this negative electrode terminal tab 25 does not have the negative electrode active material layer 22 formed on either side thereof, and is electrically connected to the upper surface of the second electrode plate 61.
The negative electrode terminal tab 25 is electrically connected to the second electrode plate 61 in a folded state with the connection portion with the outer peripheral negative electrode main body 23B as a base point.

The negative electrode 20 configured as described above has an external shape similar to that of the positive electrode 10 described above. However, the external size of the positive electrode 10 is slightly smaller (one size smaller) than the external size of the negative electrode 20.

The separator 30 shown in FIG. 4 is formed of, for example, a microporous film made of a resin such as polyolefin, a glass or resin nonwoven fabric, or a laminate of fibers such as cellulose fibers, and is capable of passing lithium ions through ion permeation holes (not shown).
The separator 30 is disposed between the entire layers of the positive electrode 10 and the negative electrode 20, and insulates the positive electrode 10 from the negative electrode 20. Thus, the separator 30 is disposed so as to be interposed between the positive electrode 10 and the negative electrode 20 at least in the entire region where the positive electrode 10 and the negative electrode 20 face each other.

Before the electrode body 2 is wound, the separator 30 is formed in a sheet shape that is wider than the positive electrode 10 and the negative electrode 20, for example, and is formed into a shape corresponding to the positive electrode 10 and the negative electrode 20 by processing such as cutting after winding.

The positive electrode 10 and the negative electrode 20 configured as described above are alternately stacked by being wound with the separator 30 sandwiched therebetween, as shown in Fig. 4. An example of a process for forming the electrode assembly 2 in which the positive electrodes 10 and the negative electrodes 20 are stacked in this manner (electrode assembly forming process) will be described below.
For example, the positive electrode 10 and the negative electrode 20 are arranged along the first direction L1 so that the positive terminal tab 15 and the negative terminal tab 25 are arranged on opposite sides of each other, and the positive electrode 10 and the negative electrode 20 are combined so that the inner circumferential side positive electrode body 13A and the inner circumferential side negative electrode body 23A overlap with the separator 30 in between. Next, as shown in Fig. 9, the positive electrode 10 and the negative electrode 20 are repeatedly wound in the same direction starting from the mutually overlapped inner circumferential side positive electrode body 13A and inner circumferential side negative electrode body 23A. Note that the separator 30 is not shown in Fig. 9.
This allows the positive electrode bodies 13 and the negative electrode bodies 23 to be stacked alternately in the stacking direction Z, thereby forming the electrode body 2 shown in FIG.

The positive electrode terminal tab 15 and the negative electrode terminal tab 25 only need to be arranged in the opposite direction when the positive electrode 10 and the negative electrode 20 are wound to form the electrode body 2, and do not necessarily need to be arranged in the opposite direction at the start of winding as described above. For example, as shown in FIG. 10, the positive electrode terminal tab 15 and the negative electrode terminal tab 25 may be arranged in the same direction, and the positive electrode 10 and the negative electrode 20 may be overlapped with the separator 30 in between, and then winding may begin. Note that the separator 30 is not shown in FIG. 10.

Furthermore, as shown in FIG. 11, the electrode body 2 may be formed by winding the positive electrode 10, the negative electrode 20, and the separator 30 using a winding machine 70 having a winding core 71.
The winding machine 70 mainly includes a winding core 71 and a pair of touch rolls 72. The winding core 71 is formed in a flat plate shape extending at a predetermined width along the winding axis O2 and is rotatable about the winding axis O2. A slit groove 71a is formed in the winding core 71 along the winding axis O2. The pair of touch rolls 72 are disposed on opposite sides of the winding core 71 and are disposed so as to be movable toward and away from the winding axis O2.

When winding is performed using the winding machine 70 configured as described above, the winding core 71 is first rotated about half a turn with the strip-shaped separator sheet 31 passed through the slit grooves 71a of the winding core 71. This allows the separator sheet 31 to be wound around both sides of the winding core 71 sandwiching the slit grooves 71a, and allows the separator sheet 31 to be arranged in a Z shape when viewed from the direction along the winding axis O2.
The separator sheet 31 is a sheet that will later function as the separator 30 .

Next, the positive electrode 10 and the negative electrode 20 are placed on either side of the winding core 71. At this time, the inner circumferential positive electrode body 13A of the positive electrode 10 is set so as to overlap the separator sheet 31, and the inner circumferential negative electrode body 23A of the negative electrode 20 is set so as to overlap the separator sheet 31. Then, by rotating the winding core 71 around the winding axis O2 in this state, the positive electrode 10, the negative electrode 20, and the separator sheet 31 can be wound flat around the winding axis O2 while being wound around the winding core 71.

This makes it possible to obtain a wound body in which the multiple positive electrode bodies 13 and the multiple negative electrode bodies 23 are arranged parallel to the winding core 71, and the multiple positive electrode connection pieces 14 and the multiple negative electrode connection pieces 24 are folded back along the side edges of the winding core 71. During winding, the pair of touch rolls 72 are constantly in contact with the wound body, thereby enabling the positive electrode 10, the negative electrode 20, and the separator sheet 31 to be tightly wound.
Finally, the winding core 71 is pulled out from the wound body in the direction of the winding axis O2, and then unnecessary portions of the separator sheet 31 are cut off, thereby forming the electrode body 2 shown in FIG.

In this embodiment, as shown in FIG. 6 , a positioning portion 100 is provided that determines the relative position of at least one of the positive electrode 10 and the negative electrode 20 at the start of winding with respect to the separator 30 .
Specifically, the positioning portion 100 is provided between the inner circumferential negative electrode body 23A located at the start of winding among the multiple negative electrode bodies 23 constituting the negative electrode 20 in the wound state electrode body 2, and the separator 30, and is equipped with a negative electrode positioning portion that positions the inner circumferential negative electrode body 23A relative to the separator 30.
The negative electrode positioning portion is an insulating adhesive layer (adhesive member according to the present invention) 80 that bonds the inner circumferential side negative electrode main body 23A and the separator 30 to each other. Since the adhesive layer 80 is provided between the inner circumferential side negative electrode main body 23A and the separator 30, it is possible to perform positioning by integrally combining the inner circumferential side negative electrode main body 23A with the separator 30.

In particular, the adhesive layer 80 is provided so as to be located between the separator 30 and an outer end portion of the inner circumferential side negative electrode main body 23A that faces the positive electrode connecting piece 14 with the separator 30 sandwiched therebetween.
At the outer end of the inner circumferential negative electrode body 23A, the negative electrode current collector 21 is exposed facing the separator 30 due to the winding relationship of the positive electrode 10 and the negative electrode 20. In this regard, as described above, since the adhesive layer 80 is disposed between the outer end of the inner circumferential negative electrode body 23A and the separator 30, the adhesive layer 80 covers the negative electrode current collector 21 exposed to the outside as if to protect it.

In addition, since the adhesive layer 80 covers the surface of the separator 30, it blocks the ion permeation holes formed in the separator 30. As a result, the adhesive layer 80 can reduce the ionic conductivity of the lithium ions that move from the positive electrode connection piece 14 through the separator 30 toward the outer end of the inner circumferential negative electrode body 23A as indicated by the arrow F1 in FIG. 6 during charging and discharging of the secondary battery 1, to a level lower than the ionic conductivity of the lithium ions that move between the positive electrode body 13 and the negative electrode body 23 through the separator 30 as indicated by the arrow F2 in FIG. 6 (i.e., the lithium ions that inherently contribute to charging and discharging).

The adhesive layer 80 can be formed by applying an adhesive 81 to the outer end of the inner circumferential negative electrode body 23A in advance when winding the positive electrode 10, the negative electrode 20, and the separator 30, i.e., when performing the electrode body forming step, as shown in Fig. 12. Note that Fig. 12 only illustrates the separator 30 and the negative electrode 20. This makes it possible to perform a positioning step of positioning the outer end of the inner circumferential negative electrode body 23A relative to the separator 30.
However, this is not limited to this case. For example, as shown in FIG. 13, adhesive 81 may be applied in advance to the separator 30 side, and the outer end of the inner circumferential negative electrode body 23A may be adhered to the separator 30 via the adhesive 81 to form an adhesive layer 80.

The adhesive 81 is not limited to a specific one as long as it has at least insulating properties. However, it is preferable that the adhesive 81 has properties such as low swelling with respect to an electrolyte solution (electrolyte), excellent adhesion to metals, flexibility when wound, a wide potential window, and material properties that are stable against oxidation and reduction potentials.
Specifically, polyacrylic acid resins, polyacrylic acid ester resins, and the like can be suitably used as the adhesive 81. Furthermore, copolymers in which part of the skeleton of these resins is substituted with styrene can also be suitably used as the adhesive 81. More specifically, "Polysol L300 (registered trademark)" manufactured by Showa Denko K.K. can be used as the adhesive 81.

In addition, during the above-mentioned positioning process, after applying adhesive 81 to the outer end portion of the inner circumferential negative electrode body 23A, when placing the negative electrode 20 in contact with the separator 30, it is preferable to previously solidify the surface or inside of the adhesive 81 or treat it so that it is in a moderately moist state.
When the adhesive 81 is the above-mentioned resin, the method of solidifying it can be, for example, a method of drying it by volatilizing the solvent by heating, or a method of chemically polymerizing it by heat treatment or exposure to ultraviolet (UV) light, etc.

The term "moderately wet state" refers to a state in which the adhesive 81 is formed by volatilizing the solvent using the method described above, but does not solidify, but contains a reduced amount of solvent. By forming such an adhesive layer 80, slippage between the negative electrode 20 and the separator 30 can be reduced when the negative electrode 20 is placed in contact with the separator 30. This makes it possible to effectively suppress the winding misalignment described below when the electrode body 2 is subsequently formed.

As the material for the adhesive layer 80, in addition to the adhesive 81 described above, polyvinylidene fluoride (PVDF), copolymers such as vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), and resins such as polyimide can be used.
When using these materials, the materials are first diluted with a solvent to gel, and then coated on the outer end of the inner circumferential negative electrode body 23A, and then completely dried or semi-dried to solidify, or treated to bring the material into a moderately moist state, before the formation of the electrode body 2 is carried out.
Among these materials, N-methylpyrrolidone (NMP) or the like can be used as a solvent for PVDF. Also, acetone or the like can be used as a solvent for PVDF-HFP. These solvents are dried before the cell (secondary battery 1) is assembled. Also, when polyimide is used, its precursor, polyamic acid or the like, can be applied to the outer end of the inner periphery side negative electrode body 23A and polymerized by heating or the like.

(Function of secondary battery)
According to the secondary battery 1 configured as described above, as shown in FIG. 2, the first electrode terminal plate 62 electrically connected to the first electrode plate 60 is exposed to the outside, and the second electrode terminal plate 63 electrically connected to the second electrode plate 61 is exposed to the outside, so that the first electrode terminal plate 62 and the second electrode terminal plate 63 can each function as an external connection terminal.
This makes it possible to use the secondary battery 1 by utilizing the first electrode terminal plate 62 and the second electrode terminal plate 63 .

In particular, according to the secondary battery 1 of this embodiment, the electrode body 2 is formed by winding the positive electrode 10 and the negative electrode 20, so that the electrode body 2 can be wound in a flat shape without protrusions and housed at high density inside the exterior body 3. This allows for improved freedom of shape and improves the volume ratio of the electrode body 2 to the entire volume of the secondary battery 1, resulting in a laminate-type secondary battery 1 with improved volumetric efficiency.

6, a positioning portion 100 having an adhesive layer 80 that functions as a negative electrode positioning portion is provided. In particular, the adhesive layer 80 can be used to position the inner periphery side negative electrode main body 23A relative to the separator 30. Therefore, when the positive electrode 10 and the negative electrode 20 that are stacked on top of each other with the separator 30 sandwiched therebetween are wound to form the electrode body 2, it is possible to suppress a shift in the relative positional relationship between the positive electrode 10 and the negative electrode 20 with the separator 30 sandwiched therebetween, that is, a so-called winding misalignment.
4, the electrode body 2 can be formed by stacking a plurality of positive electrode bodies 13 and a plurality of negative electrode bodies 23 alternately in the stacking direction Z while precisely arranging them to face each other with the separator 30 therebetween. This allows the secondary battery 1 to have improved operational reliability.

In addition, as shown in FIG. 6, the adhesive layer 80 is disposed between the outer end of the inner circumferential negative electrode body 23A and the separator 30, so that it is disposed as if to protect the negative electrode current collector 21 exposed to the outside at the outer end. Furthermore, the adhesive layer 80 blocks the ion permeation holes in the separator 30, thereby lowering the ionic conductivity of the lithium ions that move from the positive electrode connection piece 14 through the separator 30 toward the outer end, compared to the ionic conductivity of the lithium ions that move between the positive electrode body 13 and the negative electrode body 23 through the separator 30 during charging and discharging.

This makes it possible to suppress the movement of lithium ions to the exposed portion of the negative electrode current collector 21 during charging and discharging, and makes it difficult for problems such as lithium ions precipitating in needle-like form (dendrite growth) on the negative electrode current collector 21 to occur. This also makes it possible to further improve the operational reliability of the secondary battery 1.

As described above, according to the secondary battery 1 of this embodiment, it is possible to wind the positive electrode 10 and the negative electrode 20 with the separator 30 sandwiched therebetween while maintaining an appropriate relative positional relationship, and it is possible to provide a laminate-type battery equipped with the electrode body 2 with improved operational reliability.
Furthermore, since the adhesive layer 80 can function as a negative electrode positioning portion, it is easy to simplify the configuration and reduce costs.

(First Modification)
In the above-mentioned first embodiment, the case where the adhesive layer 80 is used as the negative electrode positioning portion has been described as an example, but the present invention is not limited to this case. For example, an adhesive tape having insulating properties (adhesive member according to the present invention) may be used instead of the adhesive layer 80. Even in this case, the same action and effect can be achieved.

(Second Modification)
Furthermore, the negative electrode positioning portion is not limited to the above-mentioned adhesive layer 80 or adhesive members such as adhesive tape. For example, the inner circumferential negative electrode body 23A may be positioned relative to the separator 30 by welding.

Specifically, as shown in Fig. 14, a welded portion 85 formed by welding the outer end of the inner circumferential side negative electrode main body 23A and the separator 30 to each other may function as the negative electrode positioning portion. Note that Fig. 14 illustrates only the negative electrode 20 and the separator 30.
In this case, when winding the positive electrode 10, the negative electrode 20, and the separator 30, welding can be performed at the beginning of winding to form the welded portion 85. For welding, for example, high-frequency welding, heat welding, ultrasonic welding, etc. can be used.

In this way, even when the welded portion 85 is used, the same effect as in the above embodiment can be achieved. In particular, by welding the outer end of the inner circumferential negative electrode body 23A and the separator 30 to each other, the separator 30 can be partially melted to reliably block the ion permeation holes. Therefore, the ionic conductivity of the lithium ions that move from the positive electrode connection piece 14 through the separator 30 toward the outer end of the inner circumferential negative electrode body 23A can be effectively reduced. This can further improve the operational reliability of the secondary battery 1.

In addition, the welding is not limited to welding the outer end of the inner circumferential side negative electrode body 23A and the separator 30 to each other, but as shown in Fig. 15, a part of the separator 30 may be partially and doubly welded in advance to form a separator welded part 86, and this separator welded part 86 may function as a negative electrode positioning part. Note that Fig. 15 shows only the negative electrode 20 and the separator 30.
In this case, when winding the positive electrode 10, the negative electrode 20, and the separator 30, the separator 30 is prepared in advance with the separator welded portion 86 formed thereon. Then, at the start of the winding, the negative electrode 20 is combined with the separator 30 so that the outer end of the inner circumferential side negative electrode main body 23A contacts the separator welded portion 86 as shown by the arrow in FIG. 15, and then the winding is performed.

This allows the inner circumferential negative electrode body 23A to be positioned relative to the separator 30, thereby preventing misalignment between the positive electrode 10 and the negative electrode 20 during winding. Even in this case, as shown in FIG. 16, the separator 30 can be partially melted by the separator welded portion 86 to reliably block the ion permeation holes, effectively reducing the ionic conductivity of the lithium ions that move from the positive electrode connection piece 14 through the separator 30 toward the outer end of the inner circumferential negative electrode body 23A, thereby further improving the operational reliability of the secondary battery 1.

(Third Modification)
Furthermore, in the above first embodiment, as shown in FIG. 17 , a positioning portion 100 may be provided between the positive electrode 10 and the separator 30, and a positive electrode positioning portion may be provided that positions the inner periphery side positive electrode main body 13A relative to the separator 30.
In the illustrated example, the upper and lower surfaces of the inner periphery positive electrode main body 13A are mainly wrapped with the separator 30, and then the upper and lower surfaces of the separator 30 are welded together along the positive electrode connecting piece 14 connected to the inner periphery positive electrode main body 13A to form a positive electrode side welded portion 87, which functions as a positive electrode positioning portion.
In addition, only the positive electrode 10 and the separator 30 are shown in FIG.

This makes it possible to position the inner circumferential side positive electrode main body 13A relative to the separator 30 by utilizing the positive electrode side welded portion 87. Next, as shown in Fig. 18, similarly to the above embodiment, the outer end portion of the inner circumferential side negative electrode main body 23A and the separator 30 are bonded to each other by utilizing the adhesive 81 to form an adhesive layer 80, thereby positioning the inner circumferential side negative electrode main body 23A relative to the separator 30.
At this time, the separator 30 and the negative electrode 20 are combined using the adhesive layer 80 so that the outer end of the inner circumferential side negative electrode body 23A overlaps with the positive electrode side welded portion 87.

By doing as described above, during the subsequent winding, the inner circumferential positive electrode body 13A located at the start of winding of the positive electrode 10 and the inner circumferential negative electrode body 23A located at the start of winding of the negative electrode 20 can be precisely aligned with the separator 30 in between. Therefore, it is possible to more effectively prevent the occurrence of misalignment between the positive electrode 10 and the negative electrode 20 with the separator 30 in between during winding.

The positive electrode side welded portion 87 is not limited to being formed by welding the upper and lower surfaces of the separator 30 together along the positive electrode connection piece 14. For example, it may be formed by partially welding the upper and lower surfaces of the separator 30 together so as to sandwich the positive electrode connection piece 14.

(Fourth Modification)
Furthermore, as shown in FIG. 19, the negative electrode positioning portion may be an unwound portion 88 in which a part of the separator 30 is unwound in advance.
In this case, when winding is performed using, for example, a winding machine 70 shown in Fig. 11, the winding core 71 may be rotated a predetermined number of times around the winding axis O2 to wind only the separator 30. This allows the negative electrode 20 to be combined with the separator 30 based on the unwound portion 88. That is, at the start of winding, the negative electrode 20 can be combined with the separator 30 such that the outer end of the inner circumferential negative body 23A comes into contact with the unwound portion 88.

This allows the inner circumferential side negative electrode body 23A to be positioned relative to the separator 30, making it possible to prevent misalignment between the positive electrode 10 and the negative electrode 20 during winding.
Furthermore, even in this case, the amount of idling makes it more difficult for lithium ions to pass from the positive electrode connection piece 14 to the outer end of the inner negative electrode main body 23A, thereby similarly reducing the ionic conductivity of the lithium ions.

(Fifth Modification)
In the first embodiment, the second electrode plate 61 is made of copper, but it may be made of nickel, for example. In this case, the second electrode terminal plate 63 may be omitted. In other words, an electrode terminal plate is not necessarily required for the negative electrode side, and may not be provided. In this case, the second electrode plate 61 itself can function as an external connection terminal for the negative electrode side.

(Sixth Modification)
Furthermore, in the above-described first embodiment, the secondary battery 1 is described as being circular in plan view, but the shape of the secondary battery 1 may be changed as appropriate. For example, the secondary battery may be oval in plan view, combining straight lines and semicircular portions. In this case, the shape of the electrode body 2 may be oval in plan view in accordance with the external shape of the secondary battery.

(Seventh Modification)
Furthermore, in the first embodiment, the peripheral wall portion 47 of the first laminating member 40 functions as the storage portion 45, but the present invention is not limited to this case.
For example, as shown in FIG. 20 , the second laminate member 50 may be formed to have a peripheral wall portion 58, and the peripheral wall portion 58 and the peripheral wall portion 47 of the first laminate member 40 may form the peripheral wall portion of the storage section 45 to form a secondary battery 90.
In this case, the sealing portion constituted by the first sealing tubular portion 46 and the second sealing tubular portion 56 may be formed so as to surround the entire circumference of the peripheral wall portion 47 of the first laminate member 40 from the radially outer side. Even in the case of the secondary battery 90 configured in this manner, the same effects can be achieved.

(Eighth Modification)
Furthermore, in the above first embodiment, as shown in Figure 21, the negative electrode connection piece 24 connected to the inner periphery side negative electrode main body 23A may be folded back, and the inner periphery side negative electrode main body 23A and the negative electrode main body 23 adjacent to the inner periphery side negative electrode main body 23A in an expanded state may be overlapped in advance in the stacking direction Z via the separator 30.
In this case, the electrode body 2 is positioned such that the outer end of the inner periphery negative electrode main body 23A and the negative electrode connecting piece 24 face each other via the separator 30, making it possible to prevent lithium ions from migrating from the positive electrode 10 side toward the outer end of the inner periphery negative electrode main body 23A during charging and discharging.

(Ninth Modification)
Furthermore, in the first embodiment, the entire exterior body 3 does not need to be made of a laminate film, but it is sufficient that at least a portion of the exterior body 3 is made of a laminate film.
Furthermore, the exterior body 3 is not limited to being formed of a laminate film, but may be a metallic casing. In this case, the electrochemical cell according to the present invention can be a so-called metallic button battery, and can be used as a battery with high versatility.
An example in which the exterior body is made of metal will be described in the following second embodiment.

Second Embodiment
Next, a second embodiment of an electrochemical cell according to the present invention will be described with reference to the drawings.
As shown in Figures 22 to 24, the secondary battery 110 of this embodiment is a so-called button (coin) type battery, and includes a metal outer casing 112, and a power generating element 113 and a support portion 114 housed inside the outer casing 112.

The exterior body 112 comprises a metallic container body 120 formed into a cylindrical shape with a bottom, and a metallic lid member (sealing plate according to the present invention) 130 that is welded to the container body 120 so as to close the opening of the container body 120 and forms a storage space 115 between the container body 120 and the lid member 130.
The power generating element 113 comprises an electrode body 140 having a positive electrode 142 and a negative electrode 143 arranged on either side of a separator 141, and contains an electrolyte (electrolyte solution) not shown, and is contained in a storage space 115 formed inside the outer casing 112.

In this embodiment, the axis that passes through the center of the exterior body 112 and extends in the vertical direction is called the battery axis O1. In addition, in a plan view seen from the direction of the battery axis O1, the direction that intersects with the battery axis O1 is called the radial direction, and the direction that goes around the battery axis O1 is called the circumferential direction. Furthermore, the direction from the bottom wall portion 121 of the container body 120 toward the lid member 130 along the battery axis O1 is called the upward direction, and the opposite direction is called the downward direction.

(Exterior body)
The exterior body 112 will now be described in detail.
The container body 120 is formed as a bottomed cylinder having a bottom wall portion 121 formed in a circular shape when viewed in a plane, and a peripheral wall portion 122 that is connected around the entire outer periphery of the bottom wall portion 121 and extends upward from the bottom wall portion 121.
However, the shape of the container body 120 is not limited to a bottomed cylindrical shape, and may be formed so that the outer shape is, for example, elliptical, rectangular, or polygonal in plan view.

The container body 120 is made of metal and functions as an external connection terminal for a positive electrode that is electrically connected to the electrode body 140, or an external connection terminal for a negative electrode. The thickness of the container body 120 is, for example, about 0.01 mm to 0.30 mm, and the container body 120 is a thin-walled metal container. However, in each drawing, the thickness of the container body 120 is exaggerated to make the illustration easier to see.

The specific metal material of the container body 120 varies depending on whether the container body 120 is to function as an external connection terminal for a positive electrode or an external connection terminal for a negative electrode, but may be, for example, aluminum, an aluminum alloy, copper, a copper alloy, stainless steel, or a clad material (highly functional metal material) formed by pressing the same or different metals together, but is not limited to these.
Examples of stainless steel include ferritic stainless steels such as SUS430 and SUS444, and austenitic-ferritic duplex stainless steels such as SUS329J4L.

Examples of clad materials include three-layer clad materials of Cu (inner layer)/Fe (middle layer)/Ni (outer layer), three-layer clad materials of Ni (inner layer)/Fe (middle layer)/Ni (outer layer), and three-layer clad materials of Al (inner layer)/SUS (middle layer)/Ni (outer layer). However, clad materials are not limited to three layers, and may be formed by pressing other metals together in multiple layers.

When Cu is used as the clad material, the thermal conductivity can be increased, and the heat dissipation during welding can be improved. Therefore, it is preferable to use Cu in the inner layer of the clad material, as this leads to the protection of the electrode body 140.

Furthermore, it is preferable to perform a plating process on either the inner surface or the outer surface of the clad material, or on both the inner surface and the outer surface, to form a metal plating film. By forming a metal plating film on the inner surface of the container body 120, it is possible to chemically stabilize it and improve its resistance to electrolytes and the like. In addition, by forming a metal plating film on the outer surface of the container body 120, it is possible to add functions such as an anti-rust function and reduce electrical resistance, thereby improving electrical connectivity with external terminals.

As a specific example of the metal plating film, for example, a Ni plating film, a Ni alloy plating film, etc. can be used, and in particular, it is preferable to use an alloy plating film of a eutectic metal material. When an alloy plating film of a eutectic metal material is used, for example, the melting point can be lowered when resistance welding is performed, and the temperature during welding can be lowered.
Other suitable plating films include an Au-Ni alloy plating film, an Ni-P alloy plating film, and an Ni-B alloy plating film.

Furthermore, for example, when the secondary battery 110 of this embodiment is used for a watch, it is preferable that the metal material of the container body 120 is nonmagnetic in addition to being corrosion resistant. Specifically, in addition to the above-mentioned aluminum, aluminum alloys, copper, and copper alloys, examples of stainless steel include various austenitic stainless steels such as SUS201, SUS202, SUS303, SUS304, SUS305, SUS316, SUS317, SUS321, and SUS347.
Furthermore, the container body 120 may be made of a material in which a resin layer is formed on the surface of any of the above-mentioned various metals, for example, a laminate film in which a metal layer made of stainless steel and a film-like resin layer are laminated together. In this case, the opening of the container body 120 can be closed by joining the metal lid member 130 and the metal layer of the container body 120. For example, the resin layer may be made of a resin material that is used for the sealant film 150 described later.

As shown in Figures 23 and 24, the lid member 130 is formed in a circular shape in a plan view and is formed in a cylindrical shape with a top wall portion 131 that is arranged to face the bottom wall portion 121 of the container body 120 in the direction of the battery axis O1 with the electrode body 140 in between, and an inner peripheral wall portion 132 that is connected to the entire outer periphery of the top wall portion 131 and extends upward from the top wall portion 131.

The shape of the lid member 130 only needs to correspond to the shape of the container body 120, and may be formed to correspond to the shape of the container body 120, for example, so that the outer shape is elliptical, rectangular, or polygonal in a plan view. The thickness of the lid member 130 is thin, for example, about 0.01 mm to 0.30 mm, similar to the container body 120. However, in each drawing, the thickness of the lid member 130 is exaggerated to make the illustration easier to see.

The lid member 130 is disposed inside the peripheral wall portion 122 so that the top wall portion 131 is located below the upper opening edge of the peripheral wall portion 122 of the container body 120, and the upper opening edge of the peripheral wall portion 122 and the upper opening edge of the inner peripheral wall portion 132 are flush with each other. As a result, the inner peripheral wall portion 132 is welded to the inside of the peripheral wall portion 122 of the container body 120 in a radially double-overlapping state.

The peripheral wall portion 122 and the inner peripheral wall portion 132 are firmly joined by welding around the entire circumference. This allows the lid member 130 to be used to close the opening of the container body 120, forming an accommodation space 115 (sealed space) between the container body 120 and the lid member 130 to accommodate the support portion 114 and the power generating element 113.

The method for welding the container body 120 and the lid member 130 is not particularly limited, but examples of the method that can be used include resistance welding such as laser welding, ultrasonic welding, and seam welding, and friction stir welding (FSW).
In these welding operations, the welding may be performed by a so-called workpiece moving method, in which the welding tool (not shown) is fixed and the exterior body 112, which is the work to be welded, is moved, or the welding may be performed by a so-called head moving method, in which the exterior body 112, which is the work to be welded, is fixed and the welding tool is moved. For example, when laser welding is performed by the head moving method, a galvano scanning type laser welder or the like can be adopted.

A through hole 133 is formed in the center of the lid member 130, penetrating the lid member 130 in the vertical direction and coaxial with the battery axis O1. The shape of the through hole 133 is not particularly limited, but is formed, for example, in a circular shape when viewed from above.

The lid member 130 thus configured is made of metal. As a specific metal material for the lid member 130, for example, the same type of metal material as that of the container body 120 or a different type of metal material may be adopted. When a different type of metal material from that of the container body 120 is adopted as the metal material for the lid member 130, for example, it is preferable to adopt a material having a thermal expansion coefficient similar to that of the container body 120.
Furthermore, it is preferable to form a metal plating film on either the inner surface or the outer surface, or on both the inner surface and the outer surface, of the lid member 130, in the same manner as the container body 120. As the metal plating film, the metal plating film described above can be used.

(current collector plate)
The lid member 130 configured as described above is provided with a current collector 151, at least a portion of which is exposed to the outside (upper side), and is heat-welded (sealed) via a sealant film (an insulating sealing material according to the present invention) 150, as shown in Figures 22 to 24.
Specifically, the sealant film 150 and the current collecting plate 151 are disposed on the upper surface side of the top wall portion 131 of the lid member 130, which faces in the opposite direction to the battery axis O1 from the accommodation space 115. The current collecting plate 151 is heat-welded to the upper surface of the top wall portion 131 via the sealant film 150, and is exposed upward over its entire surface.

The sealant film 150 is formed in a ring shape surrounding the through hole 133 formed in the top wall portion 131, and is arranged so as to overlap the upper surface of the top wall portion 131 while being coaxial with the battery axis O1. In the illustrated example, the sealant film 150 is formed with an inner diameter smaller than the diameter of the through hole 133.
However, this is not limiting, and the inner diameter of the sealant film 150 may be equal to or larger than the diameter of the through hole 133 .

The sealant film 150 is made of, for example, a thermoplastic resin made of polyolefin or an engineering plastic such as polyphenylene sulfide (PPS). Examples of polyolefin include polyethylene, polypropylene, and polybutene.
Furthermore, a copolymer or blend polymer of each of the above-mentioned polyolefins, or a composite material such as polypropylene reinforced with nonwoven fabric may be used as the sealant film 150. Furthermore, a plurality of sealant films 150 having different dimensions, shapes, or thicknesses may be used in a layered manner.

The current collector 151 is a metal plate that functions as an external connection terminal for a positive electrode or an external connection terminal for a negative electrode that is electrically connected to the electrode body 140. In the illustrated example, the current collector 151 is formed in a circular shape in a plan view with a diameter smaller than the outer diameter of the sealant film 150, and is arranged so as to overlap the upper surface of the sealant film 150 while being arranged coaxially with the battery axis O1. In this way, the current collector 151 blocks the through hole 133 from above.

The material of the current collector 151 is not particularly limited, but nickel, for example, can be suitably used. Furthermore, the surface of the current collector 151 that can be connected to the outside may be formed with a metal plating film made of a conductive material such as gold or nickel, or an alloy plating film containing these metals.

The above-mentioned sealant film 150 is heat-sealed to the upper surface of the top wall portion 131 and the lower surface of the current collector plate 151. As a result, the current collector plate 151 is heat-sealed to the upper surface of the top wall portion 131 via the sealant film 150, and the through hole 133 is airtightly sealed from above while maintaining insulation between the current collector plate 151 and the lid member 130. In particular, the current collector plate 151 is integrally combined with the lid member 130 via the sealant film 150.

Here, the sealant film 150 insulates the current collector 151 from the container 120. The secondary battery 110 of this embodiment can be electrically connected to either the positive or negative terminal of the electronic device by contacting the current collector 151 and the container 120 with a pressure terminal or a holder of the electronic device (not shown). In addition, a metal terminal may be further welded to at least one of the current collector 151 and the container 120, and then electrically connected to the electronic device by soldering, welding, or the like.

(pillar part)
As shown in FIGS. 23 and 24 , the support portion 114 is housed together with the power generating element 113 in the housing space 115 of the exterior body 112 .
The support column 114 is formed in an axial shape extending in the vertical direction along the battery axis O1, and is arranged coaxially with the battery axis O1. In the illustrated example, the support column 114 is formed in a hollow cylindrical shape, and its outer diameter is smaller than the diameter of the through hole 133 and the inner diameter of the sealant film 150. As a result, the support column 114 is arranged so that its upper end (first end according to the present invention) contacts the current collector plate 151 from below through the through hole 133, and its lower end (second end according to the present invention) contacts the bottom wall portion 121 of the container body 120 from above. Therefore, the support column 114 supports the current collector plate 151, which is integrally combined with the lid member 130, from below. In other words, the support column 114 supports the lid member 130 from below via the current collector plate 151.

The support 114 of this embodiment is formed of an insulating material such as an inorganic material such as ceramic or a synthetic resin material. When the support 114 is made of a synthetic resin, for example, a thermoplastic resin having a melting point equal to that of the separator 141 can be suitably used. Specifically, synthetic resin materials such as PE (polyethylene), PP (polypropylene), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), etc. can be used. Furthermore, copolymers and blend polymers of these synthetic resins can also be used.
This prevents electrical connection between the container body 120 and the collector plate 151 through the support portion 114, electrical connection between the collector plate 151 and the electrode body 140, and electrical connection between the container body 120 and the electrode body 140.

(Power generation element)
As shown in Figures 23 and 24, the power generating element 113 includes an electrode body 140 and an electrolyte (not shown), and is housed in a sealed state in the housing space 115 inside the exterior body 112 together with the support portion 114 described above.
As the electrolyte, for example, a liquid in which a supporting salt is dissolved in a non-aqueous solvent can be suitably used. As the supporting salt, for example, lithium fluorophosphate (LiPF6) can be used. As the solvent, for example, ethylene carbonate (EC) and a low boiling point solvent can be used.

However, the power generating element 113 may employ an electrode body 140 that uses an electrolyte such as a solid electrolyte, a polymer electrolyte, or a gel electrolyte instead of an electrolyte solution. Examples of polymer electrolytes include polyethylene oxide (PEO), polypropylene oxide (PPO), blended polymers containing these, polyacrylic acid esters, polymethacrylic acid esters, polysiloxanes, and polyphosphazenes. A gel electrolyte containing poly(vinylidene fluoride-co-hexafluoropropylene, PVdF-HFP) may also be used as the electrolyte solution.

(electrode body)
As shown in Fig. 23, the electrode body 140 has a positive electrode 142 and a negative electrode 143 arranged with a separator 141 sandwiched therebetween, and is a wound electrode wound multiple times around the battery axis O1. Specifically, the electrode body 140 is wound around the support part 114, with the positive electrode 142 and the negative electrode 143 overlapping with the separator 141 sandwiched therebetween, and is wound multiple times in the radial direction around the central axis C (see Fig. 4) of the support part 114 arranged coaxially with the battery axis O1. Therefore, the support part 114 also functions as a winding core when the electrode body 140 is wound.

The electrode body 140 is wound in a multiple spiral shape around the battery axis O1 (the central axis C of the support section 114) in a plan view seen from the direction of the battery axis O1. In this embodiment, the electrode body 140 is wound so that the negative electrode 143, the separator 141, the positive electrode 142, the separator 141, the negative electrode 143, the separator 141, and the positive electrode 142 are repeatedly arranged in this order from the innermost layer located on the support section 114 side of the electrode body 140 to the outermost layer located on the peripheral wall section 122 side of the container body 120.
The electrode body 140 may be a so-called pellet-type electrode body 140 having a positive electrode 142 and a negative electrode 143 on both sides of a separator 141. In addition, in each of the drawings other than Fig. 23, the illustration of the electrode body 140 is simplified.

As shown in FIG. 25, the positive electrode 142 is formed in a sheet shape with a long positive electrode collector (positive electrode collector foil) 142a formed so as to extend in a band shape of a certain width in the unfolded state before winding the electrode body 140, and a positive electrode active material layer 142b formed by coating or the like on one or both sides of the positive electrode collector 142a.

The positive electrode current collector 142a is formed in a thin sheet shape (metal foil) from a metal material such as aluminum, an aluminum alloy, or stainless steel. The thickness of the positive electrode current collector 142a is, for example, several μm to 10 and a few μm. The positive electrode active material layer 142b is formed on the positive electrode current collector 142a except for a positive electrode terminal tab 142c described later.
The positive electrode current collector 142a may be made of, for example, an etched foil, a punched metal, a sintered metal body, or a metal foam body, in addition to a metal foil.

As a material for forming the positive electrode active material layer 142b, in addition to the positive electrode active material, a conductive assistant (e.g., carbon black, graphite, etc.), a binder (e.g., polyvinylidene fluoride, etc.), and a solvent (e.g., any solvent such as N-methylpyrrolidone) can be mixed to prepare a positive electrode slurry. Note that a coating liquid containing the constituent materials for forming the positive electrode active material layer 142b can be called a "positive electrode slurry." The positive electrode active material layer 142b can be formed by coating the positive electrode slurry on the positive electrode current collector 142a and drying it.
Examples of the positive electrode active material include composite oxides containing lithium and a transition metal, such as lithium nickel-manganese-cobalt oxide (NMC), lithium nickel-cobalt-aluminate (NCA), lithium titanate (LTO), and lithium manganate (LMO).

A positive electrode terminal tab 142c is formed on one end of the positive electrode collector 142a that is located away from the support portion 114. As described above, the positive electrode terminal tab 142c does not have the positive electrode active material layer 142b formed thereon, and can be electrically connected to other components. The positive electrode terminal tab 142c is disposed on the outer layer side of the electrode body 140 when the electrode body 140 is wound.

As shown in FIG. 25, the negative electrode 143 is formed in a sheet shape including a long negative electrode collector (negative electrode collector foil) 143a formed so as to extend in a band shape with a constant width in the unfolded state before winding the electrode body 140, and a negative electrode active material layer 143b formed by coating or the like on one or both sides of the negative electrode collector 143a.

The negative electrode current collector 143a is formed in a thin sheet shape (metal foil) from a metal material such as copper, copper alloy, nickel, or stainless steel. The thickness of the negative electrode current collector 143a is, for example, several μm to 10 and a half μm. The negative electrode active material layer 143b is formed on the negative electrode current collector 143a except for a negative electrode terminal tab 143c described later.
The negative electrode current collector 143a may be made of, for example, an etched foil, a punched metal, a sintered metal body, or a metal foam body, in addition to a metal foil.

As a material for forming the negative electrode active material layer 143b, in addition to the negative electrode active material, a conductive assistant (e.g., carbon black, graphite, etc.), a binder (e.g., a dispersion of styrene-butadiene rubber (SBR)), a thickener (e.g., cellulose nanofiber (CNF), carboxymethyl cellulose, etc.), and a solvent (e.g., any solvent such as pure water) can be mixed to prepare a negative electrode slurry. Note that a coating liquid containing the constituent materials for forming the negative electrode active material layer 143b can be called a "negative electrode slurry". The negative electrode active material layer 143b can be formed by applying this negative electrode slurry to the negative electrode current collector 143a and drying it.
Examples of the negative electrode active material include silicon, silicon oxide, graphite, hard carbon, lithium titanate (LTO), LiAl, and the like, either alone or in mixture.

A negative electrode terminal tab 143c is formed on one end of the negative electrode collector 143a that is located away from the support portion 114. As described above, the negative electrode terminal tab 143c does not have the negative electrode active material layer 143b formed thereon, and can be electrically connected to other components. The negative electrode terminal tab 143c is disposed on the outer layer side of the electrode body 140 when the electrode body 140 is wound.

The separator 141 shown in FIG. 25 is formed of, for example, a microporous film made of a resin such as polyolefin, a nonwoven fabric made of glass or resin, or a laminate of fibers such as cellulose fibers, and is capable of passing lithium ions through ion permeable holes (not shown). Furthermore, the separator 141 may be, for example, a porous body capable of holding an electrolyte in the pores, or a resin layer having lithium ion conductivity.

The separator 141 is disposed between the positive electrode 142 and the negative electrode 143, and insulates the positive electrode 142 from the negative electrode 143. Therefore, the separator 141 is disposed between the positive electrode 142 and the negative electrode 143 at least in the entire area where the positive electrode 142 and the negative electrode 143 face each other.

As shown in FIG. 23, the electrode body 140 configured as described above is wound around the support portion 114, and is combined with the support portion 114 as a single unit, forming a wound electrode in which the positive electrode 142 and the negative electrode 143 are wound around the central axis C of the support portion 114 so as to be stacked in multiple layers in the radial direction with the separator 141 sandwiched between them.

In addition, the electrode body 140 housed together with the support portion 114 in the housing space 115 of the exterior body 112 has one of the positive electrode 142 and the negative electrode 143 electrically connected to the current collector plate 151, and the other electrode electrically connected to the container body 120. In addition, examples of the electrical connection include contact via a carbon-based material, welding of metals together, or contact between metals together.

In this embodiment, the negative electrode 143 is electrically connected to the current collector 151, and the positive electrode 142 is electrically connected to the container body 120. This allows the current collector 151 to function as an external connection terminal for the negative electrode, and the container body 120 to function as an external connection terminal for the positive electrode. However, this is not limited to this case, and the container body 120 may be made to function as an external connection terminal for the negative electrode by electrically connecting the negative electrode 143 to the container body 120, and the current collector 151 may be made to function as an external connection terminal for the positive electrode by electrically connecting the positive electrode 142 to the current collector 151.

When the negative electrode 143 is electrically connected to the current collector 151, for example, the negative terminal tab 143c may be electrically connected directly to the current collector 151, or the negative terminal tab 143c and the current collector 151 may be electrically connected via a conductor equivalent to a lead wire not shown.
Similarly, when electrically connecting the positive electrode 142 to the container body 120, for example, the positive electrode terminal tab 142c may be electrically connected directly to the container body 120, or the positive electrode terminal tab 142c and the container body 120 may be electrically connected via a conductor equivalent to a lead wire (not shown).

Incidentally, the secondary battery 110 of this embodiment includes a positioning portion 155 that determines the relative position of at least one of the positive electrode 142 and the negative electrode 143 at the start of winding with respect to the separator 141 shown in FIG.
Specifically, the positioning portion 155 includes a welding portion (an adhesive portion according to the present invention) 156 that fixes the support portion 114 and the separator 141. The positive electrode 142 and the negative electrode 143 are positioned on the support portion 114 using the welding portion 156 as a reference, and thus their relative positions with respect to the separator 141 are determined.

(Formation of electrode body)
In relation to the above-mentioned positioning, the case where the electrode body 140 is formed using the support portion 114 as a winding core will be described below.
25 , after preparing the separator 141, the positive electrode 142, and the negative electrode 143, the separator 141 is welded to the outer circumferential surface of the support column 114. This allows the welded portion 156 formed by welding the outer circumferential surface of the support column 114 and the separator 141 to each other to be used as a positioning portion 155, allowing the separator 141 to be positioned relative to the support column 114.

When the length of the separator 141 is determined in advance, the portion of the separator 141 that is shifted from the center in the longitudinal direction toward the region R1 where the positive electrode 142 is overlapped is welded to the outer peripheral surface of the support portion 114. This makes it possible to ensure that the region R2 where the negative electrode 143 is overlapped is larger than the region R1 where the positive electrode 142 is overlapped of the separator 141.

25, the support column 114 is rotated around the central axis C. At this time, the support column 114 is rotated so that the region R2 of the separator 141, where the negative electrode 143 is to be overlapped, is wound around the support column 114 first.
Next, as shown in Fig. 26, the separator 141 and the negative electrode 143 are overlapped so that the negative electrode 143 is inserted between the separator 141 that has been wound around the support portion 114 in advance and the support portion 114. At this time, the negative electrode 143 is inserted until it hits the welded portion 156, as indicated by an arrow S in Fig. 26. This allows the negative electrode 143 to be positioned on the support portion 114 with the welded portion 156 as a reference. Next, in this state, the support portion 114 is further rotated as shown in Fig. 27. This allows the negative electrode 143 to be wound around the support portion 114 in advance, and the innermost layer of the electrode body 140 can be formed by the negative electrode 143.

Furthermore, after the above-mentioned insertion of the negative electrode 143, the positive electrode 142 is also overlapped with the separator 141 so as to abut against the welded portion 156. This allows the positive electrode 142 to be positioned on the support portion 114 using the welded portion 156 as a reference. Thereafter, the support portion 114 is continuously rotated to wind the separator 141, the positive electrode 142, and the negative electrode 143. This allows the winding to be performed while the relative positions of the positive electrode 142 and the negative electrode 143 with respect to the separator 141 are determined.
23, it is possible to produce an electrode body 140 that is wound so as to be wound around the support part 114. Since the negative electrode 143 is wound around the support part 114 first, it is preferable that the negative electrode 143 is formed to be longer than the positive electrode 142.

(Function of secondary battery)
According to the secondary battery 110 of this embodiment configured as described above, as shown in Figures 22 to 24, the current collecting plate 151 which functions as an external connection terminal for the negative electrode is exposed to the outside, and the container body 120 which functions as an external connection terminal for the positive electrode is exposed to the outside, so that the secondary battery 110 can be used by utilizing the current collecting plate 151 and the container body 120.

In particular, according to the secondary battery 110 of this embodiment, in addition to the electrode body 140, the support portion 114 is accommodated in the accommodation space 115. The support portion 114 is arranged so that the upper end portion contacts the current collector plate 151 from below through the through hole 133, and the lower end portion contacts the bottom wall portion 121 of the container body 120 from above. This allows the support portion 114 to support the current collector plate 151 from below. Moreover, the current collector plate 151 is welded to the lid member 130 via the sealant film 150, and is therefore integrally combined with the lid member 130. Therefore, the support portion 114 can support the lid member 130 from below via the current collector plate 151.

Therefore, even if the entire exterior body 112 including the lid member 130 is formed to be thin, unintended deformation such as bending of the lid member 130 can be suppressed before welding the container body 120 and the lid member 130 together. Therefore, welding work can be performed in a state where positional deviation of the lid member 130 relative to the container body 120 is suppressed, improving work efficiency and leading to improved productivity. Furthermore, the container body 120 and the lid member 130 can be precisely and appropriately welded together, achieving reliable sealing. Therefore, a high-quality secondary battery 110 with high operational reliability can be obtained.

Furthermore, by winding the electrode body 140 around the support section 114, the positive electrode 142 and the negative electrode 143 are stacked with the separator 141 in between, forming a wound electrode wound around the central axis C of the support section 114. In other words, since the winding core used when winding the electrode body 140 is used as the support section 114, after the electrode body 140 is formed by winding, the electrode body 140 together with the support section 114 can be housed in the container body 120. This allows for efficient assembly work, which also leads to improved productivity.

Furthermore, when winding the electrode body 140 using the support part 114, the support part 114 and the separator 141 can be fixed using the welding part 156, and the separator 141 is positioned relative to the support part 114, and the positive electrode 142 and the negative electrode 143 are positioned on the support part 114 via the welding part 156, so that it is possible to prevent the relative positional relationship between the positive electrode 142 and the negative electrode 143 with the separator 141 sandwiched therebetween from shifting, i.e., the occurrence of so-called winding misalignment. This allows the electrode body 140 to be formed by precisely overlapping the positive electrode 142 and the negative electrode 143 with the separator 141 sandwiched therebetween, and allows for a secondary battery 110 with improved operational reliability.

As described above, according to the secondary battery 110 of this embodiment, it is possible to wind the positive electrode 142 and the negative electrode 143 with the separator 141 in between while maintaining an appropriate relative positional relationship, and it is possible to provide a metal case type battery equipped with the electrode body 140 with improved operational reliability.
Furthermore, even if the exterior body 112 is made thin, reliable sealing can be obtained, leading to improved productivity. Furthermore, since the current collector 151 is disposed on the upper surface side of the lid member 130, the current collector 151 can be largely exposed over the entire surface. Therefore, the current collector 151 can be effectively used as an external connection terminal for the negative electrode, making it easy to use and resulting in a secondary battery 110 with excellent mountability.

Furthermore, in the secondary battery 110 of this embodiment, if the container body 120 and the lid member 130 are formed from the clad material described above, or if the container body 120 and the lid member 130 are plated, for example, when the secondary battery 110 generates heat due to some factor and the internal pressure rises, it is possible to take a fail-safe measure such as peeling off the metal interface to release the internal pressure to the outside.

(Modification of the second embodiment)
In the second embodiment, when winding the electrode body 140 around the support portion 114, as shown in Fig. 25, the separator 141 is welded to the outer peripheral surface of the support portion 114 to form a welded portion 156, thereby preventing the separator 141 from shifting from the support portion 114, but this is not limited to the welded portion 156. For example, the separator 141 may be bonded and fixed to the outer peripheral surface of the support portion 114 using an adhesive to form an adhesive portion, thereby preventing the separator 141 from shifting from the support portion 114. In this case, the adhesive portion functions as the fixing portion in the present invention.

Third Embodiment
Next, a third embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this third embodiment, the same components as those in the second embodiment are denoted by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 28, in the secondary battery (electrochemical cell according to the present invention) 160 of this embodiment, the support part 114 is a conductor. Specifically, the support part 114 is made of metal and has a cylindrical shape. The material of the support part 114 is not particularly limited, but nickel, for example, can be suitably used, as with the current collector plate 151.

The electrode body 140 is electrically connected to the current collector 151 through the support 114 because the support 114 is a conductor. Specifically, the electrode body 140 is wound around the support 114 with the negative electrode 143 being electrically connected to the support 114. As a result, the negative electrode 143 is electrically connected to the current collector 151 through the support 114.

Furthermore, since the support portion 114 is a conductor, an insulator 161 is formed between the lower end of the support portion 114 and the bottom wall portion 121 of the container body 120 to provide insulation between the support portion 114 and the bottom wall portion 121.
In the illustrated example, the insulator 161 is formed over the entire upper surface of the bottom wall portion 121 of the container body 120. This makes it possible to electrically insulate the lower end portion of the support portion 114 and the bottom wall portion 121 by utilizing the insulator 161.

The insulator 161 does not need to be formed over the entire upper surface of the bottom wall portion 121, but may be formed at least in a region of the upper surface of the bottom wall portion 121 that comes into contact with the lower ends of the support portions 114. Furthermore, the insulator 161 may be formed not only on the upper surface of the bottom wall portion 121, but also continuously on the inner surface side of the peripheral wall portion 122.
Furthermore, the insulator 161 does not have to be formed on the bottom wall portion 121 side, and may be formed on the lower end surface of the support portion 114. Furthermore, the insulator 161 may be formed on both the upper surface of the bottom wall portion 121 and the lower end surface of the support portion 114.

The insulator 161 is not limited to a specific one, but may be, for example, an insulating synthetic resin film. Furthermore, an insulating tape made of a synthetic resin with excellent insulating properties (for example, a polyimide tape, a polyphenylene sulfide (PPS) tape, or a polyethylene terephthalate (PET) tape) may be used as the insulator 161. Furthermore, an insulating film using an insulating paint may be used as the insulator 161.

The method for establishing electrical continuity between the support portion 114 and the negative electrode 143 is not limited to a specific method, but for example, as shown in Figures 29 and 30, the separator 141 may be fixed using a welding portion 156 to prevent the separator 141 from shifting out of position relative to the support portion 114, while the negative terminal tab 143c of the negative electrode 143 may be joined to the outer circumferential surface of the support portion 114 via a joint 157 by welding or the like. In this case, the position of the welding portion 156 is used as a reference to form the joint 157, thereby allowing the relative position of the negative electrode 143 to the separator 141 to be determined.

Therefore, by rotating the support portion 114, the separator 141 and the negative electrode 143 can be wound while preventing misalignment. Furthermore, the separator 141 and the negative electrode 143 are wound around the support portion 114 first, and then the positive electrode 142 is wound around them. This allows the separator 141, the negative electrode 143, and the positive electrode 142 to be wound while preventing misalignment, and the electrode body 140 wound around the support portion 114 can be formed.

As for the positive electrode 142, as in the second embodiment, the positive electrode terminal tab 142c may be directly electrically connected to the container body 120, or the positive electrode terminal tab 142c may be electrically connected to the container body 120 via a conductor (corresponding to a lead wire) not shown.

(Function of secondary battery)
The secondary battery 160 of this embodiment configured as described above can also achieve the same effects as those of the second embodiment.
In addition, since the negative electrode 143 can be electrically connected to the current collector 151 through the support 114, a conductor (corresponding to a lead wire) is not required, and electrical resistance can be easily reduced. This makes it easier to improve the battery performance. Furthermore, since the negative electrode 143 can be electrically connected by contacting the support 114 with the current collector 151, assembly work can be performed more efficiently.

(Modification of the third embodiment)
In the third embodiment, the negative electrode terminal tab 143c is joined to the outer circumferential surface of the support portion 114 by the joint portion 157, but the present invention is not limited to this case. For example, as shown in Figures 31 and 32, a slit groove 158 may be formed in the support portion 114, and the negative electrode terminal tab 143c may be inserted into the slit groove 158 to position the negative electrode 143 with respect to the support portion 114.
The slit groove 158 is formed in the shape of a vertically long slit along the axial direction of the support column 114 and is formed so as to penetrate the support column 114 in the radial direction.

(Modification of the third embodiment)
In the third embodiment, the support portion 114 itself is formed from a metal material to function as a conductor, but this is not limited to this case, and the support portion 114 may be formed from, for example, a synthetic resin having electrical conductivity (conductive resin).
As this type of synthetic resin, from the viewpoint of mechanical strength and heat resistance, it is preferable to use engineering plastics, such as polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyether ether ketone (PEEK), perfluoroalkoxy fluororesin (PFA), etc.

Furthermore, the support portion 114 may be formed by forming the material of the support portion 114 from an insulating synthetic resin, and then forming a metal film on the outer surface of the material. Even in this case, the metal film can be used to achieve electrical connection, so the support portion 114 can function as a conductor. When forming a metal film, for example, plating can be performed by carrying out a metal spraying process or the like.

(Modification of the third embodiment)
Furthermore, in the above third embodiment, the negative electrode 143 of the electrode body 140 is electrically connected to the current collector 151 through the support portion 114. However, for example, as shown in FIG. 33 , a secondary battery (electrochemical cell according to the present invention) 170 in which the electrode body 140 is electrically connected to the container body 120 through the support portion 114 may be used.

In this case, an insulator 171 is formed between the upper end of the support portion 114 and the current collecting plate 151 to provide insulation between the support portion 114 and the current collecting plate 151. The insulator 171 may be formed in a region of the lower surface of the current collecting plate 151 with which the upper end of the support portion 114 comes into contact. This makes it possible to electrically insulate the support portion 114 and the current collecting plate 151 by utilizing the insulator 171.
The insulator 171 may be formed on the upper end surface of the support portion 114 , or may be formed on both the lower surface of the current collecting plate 151 and the upper end surface of the support portion 114 .

As for the positive electrode 142, the positive terminal tab 142c may be electrically connected directly to the current collector 151, or the positive terminal tab 142c may be electrically connected to the current collector 151 via a conductor (corresponding to a lead wire) not shown.

In the case of the secondary battery 170 configured as described above, the current collector 151 can function as an external connection terminal for the positive electrode, and the container body 120 can function as an external connection terminal for the negative electrode. Therefore, the secondary battery 170 can be used by utilizing the container body 120 and the current collector 151.

When winding the electrode body 140 around the support 114, it is not necessary to electrically connect the negative electrode 143 to the support 114, and the positive electrode 142 may be electrically connected. In this case, the positive electrode 142 and the container body 120 can be electrically connected through the support 114. With regard to the negative electrode 143, the negative terminal tab 143c may be electrically connected directly to the current collector 151, or the negative terminal tab 143c may be electrically connected to the current collector 151 via a conductor (corresponding to a lead wire) not shown.
This allows the current collector 151 to function as an external connection terminal for the negative electrode, and the container body 120 to function as an external connection terminal for the positive electrode.

Fourth Embodiment
Next, a fourth embodiment of the electrochemical cell according to the present invention will be described with reference to the drawings. In this fourth embodiment, the same components as those in the second embodiment are denoted by the same reference numerals and the description thereof will be omitted.
In the second and third embodiments, a configuration has been described as an example in which the current collecting plate 151 is welded to the lid member 130 via the sealant film 150, and the upper end of the support portion 114 is brought into contact with the current collecting plate 151 and the lower end of the support portion 114 is brought into contact with the bottom wall portion 121 of the container body 120, and the support portion 114 is then disposed in the accommodation space 115. In contrast to this, in the present embodiment, the current collecting plate 151 is welded to the bottom wall portion 121 of the container body 120 via the sealant film 150.

As shown in FIG. 34, in the secondary battery (electrochemical cell according to the present invention) 180 of this embodiment, a through hole 181 that passes through the bottom wall 121 in the vertical direction is formed in the center of the bottom wall 121 of the container body 120, coaxially with the battery axis O1. The shape of the through hole 181 is not particularly limited, but is formed, for example, in a circular shape when viewed from above.

The current collecting plate 151 is heat-welded to the bottom wall portion 121 in which the through hole 181 is formed via a sealant film 150. Specifically, the current collecting plate 151 is heat-welded to the lower surface of the bottom wall portion 121 via the sealant film 150, and is exposed downward over its entire surface.
The sealant film 150 is formed in a ring shape surrounding the through hole 181 formed in the bottom wall portion 121, and is arranged so as to overlap the lower surface of the bottom wall portion 121 while being arranged coaxially with the battery axis O1. In the illustrated example, an inner peripheral edge portion 150a of the sealant film 150 is folded back upward and protects the entire inner peripheral surface of the through hole 181 formed in the bottom wall portion 121.

The current collector 151 is formed in a circular shape in a plan view with a diameter smaller than the outer diameter of the sealant film 150, and is arranged so as to overlap the lower surface of the sealant film 150 while being coaxial with the battery axis O1. In this way, the current collector 151 blocks the through hole 181 from below.

The lid member 185 of this embodiment is formed in the shape of a flat plate that overlaps the peripheral wall portion 122 of the container body 120 from above. As a result, the lid member 185 is welded to the upper opening end of the peripheral wall portion 122 in a state where it overlaps from above all around. In the example shown, a step 185a is provided on the outer periphery of the lid member 185 at a position where it overlaps with the upper opening end of the peripheral wall portion 122. As a result, the step 185a is used to seal the storage space 115 with high airtightness.

The support portion 114 is accommodated together with the power generating element 113 in the accommodation space 115 in the exterior body 112. The support portion 114 is formed in an axial shape extending in the vertical direction along the battery axis O1, and is arranged coaxially with the battery axis O1. In the illustrated example, the support portion 114 is formed in a hollow cylindrical shape, and the outer diameter thereof is smaller than the diameter of the through hole 181 and the inner diameter of the sealant film 150.
As a result, the support pillar 114 is disposed such that its lower end (first end according to the present invention) contacts the current collector 151 from above through the through hole 181, and its upper end (second end according to the present invention) contacts the lid member 185 from below. Therefore, the support pillar 114 supports the lid member 185 from below while being supported by the current collector 151 which is integrally combined with the bottom wall 121 of the container body 120.

(Function of secondary battery)
Even in the secondary battery 180 of this embodiment configured as described above, the lid member 185 can be supported from below by utilizing the support portion 114, so that even if the entire exterior body 112 including the lid member 185 is formed to be thin, unintended deformation such as bending of the lid member 185 can be suppressed before welding the container body 120 and the lid member 185 together. Therefore, welding can be performed in a state where positional deviation of the lid member 185 relative to the container body 120 is suppressed, improving work efficiency and leading to improved productivity. Furthermore, reliable sealing can be obtained, resulting in a high-quality secondary battery 180 with high operational reliability.

Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. Examples of the embodiments and their variations include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the scope of equivalents.

For example, in each of the above embodiments, a secondary battery has been described as an example of an electrochemical cell, but the present invention is not limited to this case and can be applied to other electrochemical cells that use electrodes capable of absorbing lithium ions. Specifically, the present invention can be applied to various types of power storage devices, such as electric double layer capacitors and lithium ion capacitors.

When the electrochemical cell is applied to an electric double layer capacitor, the positive and negative electrodes may be used as a pair of polarizable electrodes. In this case, the polarizable electrodes may be, for example, those obtained by mixing powdered activated carbon obtained by activation treatment with a conductive assistant and a binder, and then rolling or pressing the mixture. The electrolyte may be, for example, those obtained by dissolving a supporting salt such as a quaternary ammonium salt in a non-aqueous solvent.
When the electrochemical cell is applied to a lithium ion capacitor, only one of the positive and negative electrodes can be the polarizable electrode described above, and the other electrode can be an electrode for a lithium ion battery. The electrolyte can be the same as that used in a lithium ion battery.

Furthermore, in the above first embodiment, lithium ions are given as an example of ions that move between the positive electrode body and the negative electrode body through the separator during charging and discharging, but this is not limited to this case, and ions of metals with a lower potential, such as sodium ions, potassium ions, and magnesium ions, may also be used.

Furthermore, in the second and third embodiments described above, the current collecting plate is arranged on the upper surface side of the top wall portion of the lid member, but this is not limited to this case, and it may be arranged on the underside of the lid member. In this case, since the current collecting plate can be arranged on the underside of the lid member, the current collecting plate and the entire lid member can be supported from below using the support portion. Therefore, unintended bending of the lid member can be effectively suppressed.

Furthermore, in the above second and third embodiments, a cylindrical support portion is used as an example, but the shape of the support portion is not limited to a cylindrical shape and may be changed as appropriate. As long as the support portion can be used as a winding core when winding the electrode body, and can support the lid member from below by having its upper end contact the current collector plate and its lower end contact the bottom wall portion when set in the storage space together with the electrode body, the outer shape may be changed as desired.

Furthermore, when the support portion is hollow, the internal shape may be, for example, a square, polygonal, star, cross, slit, etc., in plan view from the central axis direction. In particular, when such an internal shape is used, it is preferable because it makes it easier to apply a rotational torque to the support portion.

Z... Stacking direction 1, 90, 110, 160, 170, 180... Secondary battery (electrochemical cell)
2, 140: Electrode body 3, 112: Exterior body 10, 142: Positive electrode 13: Positive electrode body 14: Positive electrode connection piece 20, 143: Negative electrode 21: Negative electrode current collector 23: Negative electrode body 23A: Inner circumference side negative electrode body (first negative electrode body)
24: Negative electrode connection piece 30, 141: Separator 41, 51: Metal layer 42, 52: Inner resin layer (resin layer)
43, 53...Outer resin layer (resin layer)
80...Adhesive layer (adhesive member, negative electrode positioning portion)
85... Welded part (negative electrode positioning part)
86: Separator welded portion (negative electrode positioning portion)
88: Idle winding portion (negative electrode positioning portion)
87: Positive electrode side welded part (positive electrode positioning part)
REFERENCE SIGNS LIST 100, 155: positioning portion 114: support portion 115: storage space 120: container body 121: bottom wall portion 122: peripheral wall portion 130, 185: lid member (sealing plate)
131: Top wall portion 133: Through hole 150: Sealant film (sealing material)
151...current collecting plate 156...welded part (fixed part)

Claims (8)

an electrode assembly including a separator, a positive electrode having a positive electrode current collector , and a negative electrode having a negative electrode current collector, the positive electrode and the negative electrode being stacked with the separator sandwiched therebetween by being wound;
An exterior body that houses the electrode body therein,
At least one of the positive electrode and the negative electrode is positioned relative to the separator at a start of winding by a positioning portion ,
The electrode body is wound flat so that the positive electrodes and the negative electrodes are alternately stacked with the separator therebetween,
The positive electrode includes a plurality of positive electrode bodies arranged along a stacking direction of the electrode body, and a plurality of positive electrode connection pieces connecting the plurality of positive electrode bodies to each other,
The negative electrode includes a plurality of negative electrode bodies arranged along a stacking direction of the electrode body, and a plurality of negative electrode connection pieces connecting the plurality of negative electrode bodies to each other,
the electrode body is formed by winding the positive electrode connection piece and the negative electrode connection piece in a folded manner, so that the positive electrode main body and the negative electrode main body are arranged in a state in which they face each other alternately in the stacking direction with the separator interposed therebetween,
the positioning portion includes a negative electrode positioning portion provided between a first negative electrode body located at a winding start side among the plurality of negative electrode bodies and the separator, and which positions the first negative electrode body with respect to the separator,
an electrochemical cell characterized in that the negative electrode positioning portion is arranged so as to be located between the separator and an outer end portion of the first negative electrode main body that faces the positive electrode connection piece across the separator, and is arranged so as to integrally combine the outer end portion and the separator, and to cover, from the separator side, a portion of the negative electrode current collector that is exposed to the outside at the outer end portion of the first negative electrode main body . 2. The electrochemical cell of claim 1 ,
An electrochemical cell in which the negative electrode positioning portion reduces the ionic conductivity of ions that move from the positive electrode connection piece toward the outer end through the separator during charging and discharging to less than the ionic conductivity of ions that move between the positive electrode main body and the negative electrode main body through the separator. 3. The electrochemical cell of claim 2 ,
an electrochemical cell, wherein the negative electrode positioning portion is an insulating adhesive member that bonds the outer end portion of the first negative electrode body and the separator to each other, and blocks an ion permeation hole formed in the separator; 3. The electrochemical cell of claim 2 ,
an electrochemical cell, wherein the negative electrode positioning portion is a welded portion formed by welding the outer end portion of the first negative electrode body and the separator to each other, and the welded portion blocks an ion permeation hole formed in the separator by the welding. 5. The electrochemical cell according to claim 1 ,
The electrochemical cell, wherein the exterior body is formed of a laminate film having a metal layer and a resin layer covering both sides of the metal layer. an electrode assembly including a separator, a positive electrode having a positive electrode current collector, and a negative electrode having a negative electrode current collector, the positive electrode and the negative electrode being stacked on top of each other with the separator sandwiched therebetween, the positive electrode and the negative electrode being wound flat so that the positive electrode and the negative electrode are alternately stacked with the separator sandwiched therebetween;
An exterior body that houses the electrode body therein,
The positive electrode includes a plurality of positive electrode bodies arranged along a stacking direction of the electrode body, and a plurality of positive electrode connection pieces connecting the plurality of positive electrode bodies to each other,
A method for manufacturing an electrochemical cell, the negative electrode comprising: a plurality of negative electrode bodies arranged along a stacking direction of the electrode body; and a plurality of negative electrode connection pieces connecting the plurality of negative electrode bodies to each other,
an electrode body forming step of forming the electrode body by folding back the positive electrode connection piece and the negative electrode connection piece, so that the positive electrode main body and the negative electrode main body are arranged in a state where they face each other alternately in the stacking direction with the separator interposed therebetween;
During the electrode body forming step,
a positioning step of positioning the first negative electrode body relative to the separator by providing a negative electrode positioning portion between a first negative electrode body located at a winding start side among the plurality of negative electrode bodies and the separator;
a negative electrode positioning portion disposed between the separator and an outer end portion of the first negative electrode main body that faces the positive electrode connection piece across the separator during the positioning step, the negative electrode positioning portion being disposed between the separator and an outer end portion of the first negative electrode main body that faces the positive electrode connection piece across the separator, the outer end portion and the separator being integrally combined by the negative electrode positioning portion, and the negative electrode positioning portion being disposed to cover a portion of the negative electrode current collector that is exposed to the outside at the outer end portion of the first negative electrode main body from the separator side . 7. The method of claim 6 for producing an electrochemical cell, comprising:
a surface of the separator is covered with the negative electrode positioning portion during the positioning step so as to block ion permeation holes formed in the separator, and the ionic conductivity of ions moving from the positive electrode connection piece toward the outer end portion through the separator is reduced to be lower than the ionic conductivity of ions moving between the positive electrode main body and the negative electrode main body through the separator. 8. The method for producing an electrochemical cell according to claim 6 or 7 ,
An insulating adhesive material is used as the negative electrode positioning portion,
During the positioning step,
A method for manufacturing an electrochemical cell, comprising: applying the adhesive member to the outer end of the first negative electrode body or to a surface of the separator facing the outer end of the first negative electrode body; solidifying or wetting at least a portion of the applied adhesive member; and then bonding the outer end of the first negative electrode body and the separator to each other to position them.