WO2007049352A1

WO2007049352A1 - Electric double layer capacitor

Info

Publication number: WO2007049352A1
Application number: PCT/JP2005/019883
Authority: WO
Inventors: Yong Wook Lee; Sung Hyun Yoon
Original assignee: Kitagawa Seiki Kabushiki Kaisha
Priority date: 2005-10-28
Filing date: 2005-10-28
Publication date: 2007-05-03

Abstract

An electric double layer capacitor which employs a unit cell (10) comprising upper and lower noncontact metal cases (1, 2), two polarization electrodes (3a, 3b) having a surface impregnated or coated with electrolyte and attached tightly or bonded to the inner surfaces of the upper and lower metal cases (1, 2), a short circuit prevention separator (4) arranged between the two electrodes (3a, 3b), and an insulating gasket (9) fitted between the upper and lower metal cases (1, 2). The electric double layer capacitor comprises an insulating container (16), for containing the unit cell (10), having a through opening (18) in the bottom face or a bottom plate (17) and containing the unit cell (10) such that the lower surface of the lower metal case (2) of the unit cell (10) touches the upper surface of the bottom plate (17), an upper terminal (20) having one end bonded to the upper metal case (1) and the other end extending horizontally on a plane substantially identical to the lower surface of the bottom plate (17), and a lower terminal (30) provided with a first end portion (32) having one end passing the through opening (18) and bonded to the surface of the lower metal case (2) and a second end portion (34) extending horizontally on a plane substantially identical to the lower surface of the bottom plate (17).

Description

Specification

Electric double layer capacitor

Technical field

The present invention relates to an electric double layer capacitor used as an auxiliary power supply or main power supply for various electronic products, and in particular, a chip-type electric double layer which is compact and excellent in electrical stability and thermal stability. It relates to a capacitor.

Disclosure of the invention

An electrical double layer capacitor (Electric Double Layer Capacitor, EDLC) is a capacitor that stores electrical energy using an electrical double layer phenomenon formed at the interface between a solid and an electrolyte. Electric double-layer capacitors have high-density energy rapid charge and discharge characteristics, and are widely used as an auxiliary power source or main power source for mobile communication devices and portable electronic products such as notebook computers. ing.

In addition, the above-mentioned portable electronic products are required to be further miniaturized and slimmed, and therefore, various electronic components mounted on these products are also demanded to be miniaturized (for example, chip formation). There is. The requirement for such miniaturization is the same for the electric double layer capacitor.

When mass-producing an electronic product incorporating such a small electric double layer capacitor, it is preferable to mount the capacitor on the substrate by surface mounting using solder reflow or the like in terms of manufacturing efficiency. In chip-type electric double layer capacitors, both sides of the chip capacitor are positive and negative respectively, and when surface mounting this, the conductive plate is extended from either or both of positive and negative electrodes. Make sure that one of the electrodes and a part of the conductive plate or both of the parts of the conductive plate that extends as much as possible are on the same plane.

FIG. 1 is a partially cutaway perspective view of a conventional chip-type electric double layer capacitor, and FIG. 2 is a side view of this electric double layer capacitor. The unit cell 10 of the chip-type electric double layer capacitor has a disk-like shape as a whole, and the upper and lower surfaces thereof are positive and negative. The unit cell 10 has a configuration in which a pair of electrodes 3a and 3b is disposed between the upper metal case 1 and the lower metal case 2 with a separator for preventing short circuit. Upper electrode 3a The lower electrode 3 b is joined to the inner surface (lower surface) of the upper metal case 1 and to the inner surface (upper surface) of the lower metal case 2.

An electrolyte is impregnated in each of the upper electrode 3a and the lower electrode 3b. Thus, when the pair of electrodes containing the electrolyte are opposed via the separator, the function as an electric double layer capacitor is realized by the configuration. A gasket 9 is inserted between the upper metal case 1 and the lower metal case 2. The gasket 9 prevents short circuiting due to direct contact between the upper metal case 1 and the lower metal case 2 and also prevents electrolyte leakage.

This electric double layer capacitor has an upper terminal 5 and a lower terminal 6 for surface mounting on a PCB substrate. The upper terminal 5 and the lower terminal 6 are formed of a material having conductivity, for example, metal.

As shown in FIG. 2, upper terminal 5 is an elongated plate-like member, one end of which is electrically connected to upper metal case 1 by means such as spot welding or soldering. While being joined to the upper surface of the upper metal case 1. The upper terminal 5 extends outward in the radial direction of the upper metal case 1 and is bent downward at a position slightly outward from the upper surface of the upper metal case 1. A downward portion 5a is formed on the side away from the joining position with the metal case 1). The downward portion 5a is bent again at a position near the lower surface of the lower metal case 2 and radially outward from the position toward the tip side (the side away from the joint position force with the upper metal case 1) outward force outward portion 5b is formed. The upper surface of the outward portion 5 b is positioned substantially flush with the lower surface of the lower metal case 2, and the position of the outward portion 5 b is slightly below the lower surface of the lower metal case 2.

The lower terminal 6 is also an elongated plate-like member. One end of the lower terminal 6 is joined to the lower surface of the lower metal case 2 while securing conduction with the lower metal case 2 by means such as spot welding or soldering. The lower terminal 6 extends outward in the radial direction of the lower surface of the lower metal case 2, and the tip thereof protrudes from the lower surface of the lower metal case 2.

Here, since the plate thicknesses of the upper terminal 5 and the lower terminal 6 are substantially the same, the lower surface of the outwardly-facing portion 5 b of the upper terminal 5 and the lower surface of the lower terminal 6 are substantially coplanar. . For this reason, when the capacitor is placed on the substrate, the flat portion of the substrate is exposed to the outside portion 5b of the upper terminal. The lower surface and the lower surface of the lower terminal 6 abut each other, and the lower surface of the lower metal case 2 slightly floats above the surface portion of the substrate. Fig. 3 is a top view when the capacitor is mounted on the substrate B, and Fig. 4 is a side view when the capacitor is mounted on the substrate B. When surface mounting is performed by means of solder reflow or the like with the capacitor placed on the substrate B, the outwardly directed portion 5b of the upper terminal 5 and the lower terminal 6 are not Soldered to B

When the capacitor is mounted on the substrate in such a state, the contact area between the upper terminal 5 and the lower terminal 6 and the substrate needs to be sufficiently large, and the upper terminal 5 and the lower terminal 6 have the radius of the capacitor. It must be made to project largely in the direction outside. For this reason, it is necessary to increase the area of the substrate B by the amount of protrusion of the upper terminal 5 and the lower terminal 6, which is contrary to the demand for downsizing and slimming of electronic devices using capacitors. In addition, since the lower metal case 2 and the lower part 5a and the outer part 5b of the upper terminal 5 are close to each other, there is a problem that a short circuit is likely to occur due to their contact.

The objects described in FIGS. 5 to 7 are provided to achieve the purpose of reducing the substrate area for mounting a capacitor. Fig. 5 is a side view of the improved capacitor, Fig. 6 is a top view when the capacitor is mounted on the substrate B, and Fig. 7 is a side view of the capacitor mounted on the substrate B. As shown, in this modification, the upper terminal 7 joined to the upper surface of the upper metal case 1 of the unit cell 10 is bent in a U-shape. That is, the upper terminal 7 extends outward in the radial direction of the upper metal case 1 and is bent downward at a position slightly projecting outward from the upper surface of the upper metal case 1, and the tip side (upper A downward portion 7a is formed on the side of the joint portion with the metal case 1). The downward portion 7a is bent again at a position slightly below the lower surface of the lower metal case 2, and a radially inward portion 7b is formed on the tip side from the position. As a result, the tip of the inward portion 7 b of the upper terminal 7 is under the lower metal case 2. At this time, the lower surface of the inward portion 7b of the upper terminal 7 and the lower surface of the lower metal case 2 are in a substantially parallel relationship. The upper surface of the inward portion 7 b of the upper terminal 7 is slightly separated from the lower surface of the lower metal case 2.

Also, the lower terminal 8 whose one end is joined to the lower surface of the lower metal case 2 has a crank shape. The upper surface of the tip side of the lower terminal 8 (the side away from the joining position with the lower metal case 2) is bent twice, and the lower surface force of the lower metal case 2 is also slightly separated. Here, the heights of the lower surface of the inward portion 7b of the upper terminal 7 and the lower surface of the tip of the lower terminal 8 are approximately equal, and when the capacitor is placed on the substrate B, as shown in FIG. The lower surface of the inward portion 7b of the terminal 7 and the lower surface of the tip of the lower terminal 8 are in contact with the upper surface of the substrate B. In this state, the terminal and the substrate B are joined by solder reflow or the like.

In this improvement, the bent portion of the lower terminal 8 is formed immediately below the lower metal case 2. As a result, the contact area between the lower terminal 8 and the substrate B can be sufficiently secured so that the lower terminal 8 hardly protrudes outward in the radial direction of the lower metal case 2. Also, by making the inward portion 7b of the upper terminal 7 deeply indented below the lower metal case 2, the upper terminal 7 and the substrate B can hardly project the upper terminal 7 radially outward of the lower metal case 2. The contact area with can be secured.

In this configuration, since the upper terminal 7 joined to the upper metal case 1 is recessed under the lower metal case 2 in this configuration, the substrate B and the upper terminal 7 can be soldered. There is a possibility that solder will flow in the gap between the upper surface of the inward portion 7b of the upper terminal 7 and the lower surface of the lower metal case 2 and a short may occur between the lower metal case 2 and the upper terminal 7 o

Further, when the capacitor is mounted on the substrate, the capacitor is temporarily exposed to a high temperature atmosphere of about 240 ° C. to 280 ° C. In order to prevent damage to the capacitor and performance degradation due to this high temperature, it is desirable to have a configuration that enables thermal protection during mounting of the capacitor, especially the electrodes.

The present invention was devised to solve the problems of the conventional electric double layer capacitor described above, and it is an electronic device in which the capacitor is used while keeping the area of the substrate required for mounting the capacitor small. The present invention provides an electric double layer capacitor capable of preventing a short circuit of an electrode due to a flow of solder and the like while achieving downsizing and slimming, and further protecting a thermal capacitor at the time of mounting.

In order to achieve the above object, an electric double layer capacitor according to one aspect of the present invention is an insulating container (16) for housing a unit cell (10), and a bottom plate (17) which is a bottom surface thereof. And the unit cell (10) is housed so that the lower surface of the lower metal case (2) of the unit cell (10) abuts on the upper surface of the bottom plate (17). And an upper terminal (20) configured such that one end is joined to the upper metal case (1) and the other end horizontally extends on substantially the same plane as the lower surface of the bottom plate (17). A first end (32), one end of which passes through the through opening (18) and is joined to the surface of the lower metal case (2), and a lower surface of the bottom plate And a lower terminal (30) having a second end (34) extending to the

According to the above configuration, since the unit cell is housed in the insulating container, direct contact between the lower metal case and the upper terminal of the unit cell is prevented, and solder flow occurs when the capacitor is mounted. However, shorting between the lower metal case and the upper terminal is prevented.

The upper terminal (20) force extends outward in the planar direction of the upper surface of the upper metal case (1), and at least a portion thereof is joined to the upper metal case (1), and an upper end (22) A downward portion (24) which is bent downward from the upper end and comes close to the outside of the side wall (19) of the container (16), and which is bent from the lower side of the downward portion (24) and the insulating container (16) The inward portion (28) may be extended on a horizontal surface below the bottom plate (17) of the second embodiment.

With such a configuration, the upper terminal hardly protrudes radially outward from the insulating container, and the inward portion, which is the tip of the upper terminal, is indented under the insulating container. Therefore, the area of the substrate necessary for mounting the capacitor on the substrate can be reduced, and miniaturization and slimming of the electronic device using the capacitor can be expected.

Preferably, the lower terminal (30) is a plate-like member bent in a crank shape.

In addition, the container (16) is preferably formed of heat resistant resin such as polyester resin, ABS resin, nylon resin and the like. In addition, the upper and Z or lower terminals (20, 30) are preferably metal plates such as stainless steel, nickel, aluminum, titanium and the like.

The upper and Z or lower terminals (20, 30) may be connected to the upper or lower metal case (1, 2) by soldering or spot welding.

Brief description of the drawings FIG. 1 is a partially cutaway perspective view of a conventional electric double layer capacitor.

FIG. 2 is a side view of a conventional electric double layer capacitor.

FIG. 3 is a top view of the conventional electric double layer capacitor mounted on a substrate.

[FIG. 4] It is a side view when the conventional electric double layer capacitor is mounted on a substrate.

FIG. 5 is a side view of an electric double layer capacitor which is an improved example of the conventional one.

FIG. 6 is a top view of an electric double layer capacitor, which is an improved example of the prior art, mounted on a substrate.

FIG. 7 is a side view of an electric double layer capacitor, which is an improved example of the conventional one, mounted on a substrate.

FIG. 8 is an exploded perspective view of an electric double layer capacitor according to an embodiment of the present invention.

FIG. 9 is a side view of the electric double layer capacitor of the embodiment of the present invention.

FIG. 10 is a top view when the electric double layer capacitor of the embodiment of the present invention is mounted on a substrate.

FIG. 11 is a side view of the electric double layer capacitor according to the embodiment of the present invention mounted on a substrate.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 8 is an exploded perspective view of the electric double layer capacitor of the present embodiment. FIG. 9 is a side view of the electric double layer capacitor of the present embodiment. The unit cell 10 in the electric double layer capacitor of this embodiment is the same as the unit cell 10 in the conventional electric double layer capacitor shown in FIG.

That is, the unit cell 10 has a disk-like shape as a whole, and the upper and lower surfaces thereof are positive and negative. The unit cell 10 has a configuration in which a pair of electrodes 3a and 3b is disposed between the upper metal case 1 and the lower metal case 2 with a separator for preventing short circuit. The upper electrode 3 a is joined to the inner surface (lower surface) of the upper metal case 1, and the lower electrode 3 b is joined to the inner surface (upper surface) of the lower metal case 2.

Each of the upper electrode 3a and the lower electrode 3b is impregnated with an electrolyte. Thus, when a pair of electrodes containing an electrolyte are opposed via a separator, depending on the configuration, The function as an electric double layer capacitor is realized. A gasket 9 is inserted between the upper metal case 1 and the lower metal case 2. The gasket 9 prevents short circuiting due to direct contact between the upper metal case 1 and the lower metal case 2 and prevents electrolyte leakage.

Here, the upper and lower metal cases 1 and 2 are usually formed using a metal such as stainless steel, nickel, aluminum, titanium or the like. Also, the metal case 1 or 2 may be coated with nickel or aluminum.

The electric double layer capacitor of the present embodiment has this unit cell 10, an insulating container 16 for housing the unit cell 10, and upper and lower terminals 20, 30. The container 16 is provided with a disc-shaped bottom plate 17 and a side wall 19 whose entire circumferential force of the edge of the bottom plate 17 also extends substantially vertically upward (that is, substantially annular shape). Further, the bottom plate 17 is formed with a through opening 18. Here, the unit cell 10 is housed in the insulating container so that the lower surface of the lower metal case 2 and the upper surface of the bottom plate 17 abut.

[0031] The insulating container 16 is formed of an insulating resin. Further, this resin is preferably formed of a heat-resistant resin, for example, polyester lubricant (PPS), ABS or nylon resin, in consideration of soldering the electric double layer capacitor to the substrate. . Also, in order to miniaturize the electric double layer capacitor, the bottom plate 17 and the side wall 19 can ensure sufficient rigidity of the insulating container 16 and can sufficiently protect the heat of the solder reflow of the unit cell 10 at the time of substrate mounting. Within the range, it is formed as thin as possible. The inner diameter of the side wall 19 of the insulating container 16 is configured to be equal to or slightly larger than the inner diameter of the lower surface of the unit cell 10, and when the unit cell 10 is housed in the insulating container 16, the unit cell 10 is parallel in the horizontal direction. Don't move!

An upper terminal 20 is joined to the upper surface of the upper metal case 1. The upper terminal 20 is a member formed by bending a substantially rectangular metal plate into a U-shape, and the upper end 22 which is one end thereof is joined to the upper surface of the upper metal case 1 by spot welding or soldering. ing. As shown in FIG. 9, the upper end 22 extends radially outward of the upper metal case 1 and is bent downward at a position where the upper edge force of the upper metal case 1 slightly protrudes. . A portion from this bent bend (ie, substantially vertical The downward extending portion is defined as the downward portion 24.

One surface of the downward portion 24 is substantially in contact with the outer peripheral portion of the side wall 19 of the insulating container 16. That is, the downward portion only slightly protrudes from the insulating container 16. The tip side of the downward portion 24 is bent along the bottom plate 17 of the insulating container 16 and extends horizontally under the bent portion of the bent portion (i.e., below the bottom plate 17). Part) is defined as inward part 28.

A lower terminal 30 is joined to the lower surface of the lower metal case 2. The lower terminal 30 is a member formed by bending a rectangular metal plate into a crank shape. As shown in FIG. 9, the first end 32 of the lower terminal 30 is joined to the upper surface of the upper metal case 1 by spot welding or soldering through the through opening 18 of the insulating container 16. Ru. In addition, the second end 34 of the lower terminal 30 extends radially outward of the bottom plate 17 along the lower surface of the bottom plate 17 of the insulating container 16. Also, the tip end of the second end 34 does not protrude radially outward from the bottom plate 17.

[0035] The lower terminal 30 and the upper terminal 30 are prevented from contacting the second end 34 of the lower terminal 30 and the inward portion 28 of the upper terminal 20 or conducting solder via solder during solder reflow. It is sufficiently separated from the inward part 28 of the terminal 20.

Upper terminal 20 and lower terminal 30 are formed of stainless steel, nickel, aluminum, titanium or the like.

As described above, according to the present embodiment, since the upper terminal 20 and the lower terminal 30 are configured to hardly protrude radially outward from the insulating container 16, the electric double layer capacitor is When mounting on a PCB substrate etc., the required substrate area can be minimized. That is, by using the electric double layer capacitor of the present embodiment, it is possible to achieve downsizing and slimming of an electronic device using the capacitor.

FIG. 10 is a top view when the electric double layer capacitor of the present embodiment is surface mounted on a PCB substrate B. FIG. 11 is a side view of the electric double layer capacitor surface-mounted on the PCB substrate B-like.

As shown in FIG. 11, according to the present embodiment, since the insulating container 16 is interposed between the upper terminal 20 and the lower metal case 2, the upper terminal 20 and the lower metal are disposed. Case The upper terminal 20 and the lower metal case 2 are not brought into direct contact with each other or by soldering, and there is no short circuit between the two. Further, since the inward portion 28 of the upper terminal 20 and the lower terminal 30 are sufficiently separated, the inward portion 28 and the lower terminal 30 are joined by solder even if solder flow occurs during solder reflow. There is nothing to do. That is, according to the electric double layer capacitor of the present embodiment, the upper case 1 and the lower case 2 do not short-circuit due to the solder flow at the time of the solder reflow.

Further, according to the present embodiment, since the lower surface of the lower metal case 2 is covered with the insulating container 16 having a high thermal insulation property, the temperature rise of the unit cell 10 can be sufficiently suppressed during the solder reflow. Thus, the capacitor performance of the unit cell 10 is prevented from being deteriorated due to the temperature rise.

Claims

The scope of the claims

[1] Upper and lower metal cases (1, 2) which are not in contact with each other, and electrolytes are impregnated or coated on the surface, and the inner surface of the upper and lower metal cases (1, 2) Two polarizable electrodes (3a, 3b) closely attached to or bonded to the surface, a short-circuit preventing separator (4) disposed between the two electrodes (3a, 3b), and the upper and lower metal sheets A unit cell (10) comprising an insulating gasket (9) inserted between the slots (1, 2); and an insulating container (16) for housing the unit cell (10), A through hole (18) is formed in a bottom plate (17) which is the bottom surface of the unit cell (10) so that the lower surface of the lower metal case (2) abuts on the upper surface of the bottom plate (17). ) Will be stored! /,

One end is joined to the upper metal case (1) and the other end is horizontally extended on the same plane as the lower surface of the bottom plate (17)! The upper terminal (20),

The first end (32), one end of which passes through the through opening (18) and is joined to the surface of the lower metal case (2), and the lower surface of the bottom plate (17) A lower terminal (30) having a second end (34) extending to the

Having an electric double layer capacitor.

[2] An upper end (22) in which the upper terminal extends outward in the planar direction of the upper surface of the upper metal case (1) and at least a part of which is joined to the upper metal case (1); A downward portion (24) which is bent downward from the side of the insulating container (16) adjacent to the outside of the side wall (19), and is bent from the lower side of the downward portion (24) to form the insulating container (16) An electric double layer capacitor according to claim 1, characterized in that it comprises an inward portion (28) extending on a horizontal plane below the bottom plate (17).

[3] The electric double layer capacitor according to claim 1 or 2, wherein the lower terminal (30) is a plate-like member bent in a crank shape.

[4] The electric double layer capacitor according to any one of claims 1 to 3, wherein the insulating container (16) is formed of a heat resistant resin.

[5] The electric double layer capacitor according to claim 4, characterized in that the insulating container (16) is formed of a polyester lubricant.

[6] The insulating container (16) is characterized in that it is formed of an ABS resin.

The electric double layer capacitor according to 4.

[7] The electric double layer capacitor according to claim 4, wherein the insulating container (16) is formed of nylon resin.

[8] The electric double layer capacitor according to any one of claims 1 to 7, wherein the upper and Z or lower terminals (20, 30) are metal plates.

[9] The upper and Z or lower terminals (20, 30) may be formed of stainless steel,

The electric double layer capacitor according to claim 8, characterized in that

[10] The electric double layer capacitor according to claim 8, characterized in that nickel force is also formed on the upper and Z or lower terminals (20, 30).

[11] The upper and Z or lower terminals (20, 30) are also formed of aluminum force,

The electric double layer capacitor according to claim 8, characterized in that

[12] The electric double layer capacitor according to claim 8, characterized in that the upper and Z or lower terminals (20, 30) are made of titanium !.

[13] The upper and lower terminals (20, 30) according to any one of claims 8 to 12, wherein the upper and lower terminals (20, 30) are joined to the upper or lower metal case (1, 2) by soldering. The electric double layer capacitor as described in.

[14] The upper and lower terminals (20, 30) according to any one of claims 8 to 12, wherein the upper and lower terminals (20, 30) are joined to the upper or lower metal case (1, 2) by spot welding. The electric double layer capacitor as described in.