JP2003272966A - Electric double layer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively reduce an electric resistance of junctions interconnecting electrodes (cell terminals) of electric double layer capacitor cells in an electric double layer capacitor which is a module formed by using the required number of electric double layer capacitor cells. <P>SOLUTION: The junction interconnecting the electrodes 11 of the electric double layer capacitor cells 10 is made by lapping the flat plate electrodes 11 to connect them by riveting and further forming a welded part 12 by TIG welding. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor composed of a required number of electric double layer capacitor cells in one module.

[0002]

2. Description of the Related Art In recent years, as various power storage devices, attention has been paid to a technique of applying an electric double layer capacitor, which can be rapidly charged and has a long charge / discharge cycle life.

A single electric double layer capacitor (capacitor cell) has a low withstand voltage (about several volts). Therefore, when it is applied to a drive power source of an electric vehicle, many of them are connected in series and in parallel to have a predetermined capacity. Composition of electric double layer capacitor (capacitor module)
-114121).

[0004]

In FIG. 4, 1 is an electric double layer capacitor, 4 is a pair of electrodes (cell terminals) drawn out of the container 2 (case), and each electrode 4
The a and 4b are formed in a short shape from aluminum which is lightweight and has low resistance. In the case of the electric double layer capacitor 1, two sets are connected in parallel, and these sets are connected in series.

5 and 6, 4a and 4a are 1
One set of positive and negative cell terminals 4b and 4b are the other set of negative and negative cell terminals.
a, 4a, 4b and 4b are superposed. It is a pair of plate-shaped members 5 that sandwich these overlapping portions from the plate thickness direction.
a and 5b, and tightening means 6 (bolts or the like) are provided at both ends thereof. And the four electrodes 4a, 4a,
4b and 4b are sandwiched between a pair of plate-shaped members 5a and 5b, and are joined to each other by the tightening force of both ends.

The electric double layer capacitor 1 is composed of a positive electrode body, a negative electrode body and a separator interposed therebetween in a laminated body. The positive electrode body and the negative electrode body are composed of a collecting electrode and polarizable electrodes (activated carbon electrodes) on both surfaces thereof. These collector electrodes are made of a rectangular aluminum foil, and a strip-shaped lead portion is integrally formed on one side of the rectangular plane so as to be closer to one side. The same poles of the lead portions are bundled together, and the electrodes 4 having the same polarities are joined to the bundled portion.

The laminated body is housed in a container 2 and immersed in an electrolytic solution. The container 2 is a resin film (for example, an aluminum laminated film) made of a flexible material having a laminated structure including a metal layer.
Is formed into a bag shape, and a part of the electrode 4 is drawn out from the opening portion on one side thereof. Excessive electrolytic solution is extracted from the inside of the container 2 and sealed in a vacuum state.

At the connecting (joining) portion connecting the electrodes 4 of the electric double layer capacitors 1 to each other, a pair of plate-like members 5 are provided.
The overlapping portions of the electrodes 4 between a and 5b are tightened in a close contact state, but this makes it difficult to suppress the contact resistance between the electrodes 4 to be small. Further, the contact resistance between the electrodes 4 varies greatly depending on the surface condition of the electrodes 4 and the degree of tightening. For this reason, even if a high-performance electric double layer capacitor (single cell) is completed, it may not lead to stable performance improvement of the electric double layer capacitor module.

The present invention has been made in view of such a problem, and is effective for stably suppressing the electric resistance of a connecting portion connecting electrodes (cell terminals) of electric double layer capacitors to a small value. The purpose is to provide means.

[0010]

According to a first aspect of the present invention, in an electric double layer capacitor composed of a required number of electric double layer capacitor cells into one module, a connecting portion connecting electrodes of the electric double layer capacitor cells. Is characterized in that plate-shaped electrodes are overlapped with each other, and the gaps between these plate thicknesses are welded by TIG welding.

According to a second aspect of the present invention, in an electric double layer capacitor composed of a required number of electric double layer capacitor cells into one module, a connecting portion connecting electrodes of the electric double layer capacitor cells is formed in a plate shape. The electrodes to be formed are overlapped with each other, and the gaps between these plate thicknesses are welded by laser welding.

According to a third aspect of the present invention, in an electric double layer capacitor composed of a required number of electric double layer capacitor cells into one module, a connecting portion connecting electrodes of the electric double layer capacitor cells is formed in a plate shape. It is characterized in that the electrodes to be formed are overlapped with each other, and the plate thicknesses are welded by TIG welding in addition to the rivet connection.

According to a fourth aspect of the present invention, in an electric double layer capacitor composed of a required number of electric double layer capacitor cells into one module, a connecting portion connecting electrodes of the electric double layer capacitor cells is formed in a plate shape. It is characterized in that the electrodes to be formed are overlapped with each other, and those plate thicknesses are welded by spot welding in addition to rivet connection.

[0014]

In the first invention, the TIG (Tungst
Welding between the electrodes results in complete welding between the electrodes, and the electrical resistance of these connections is reduced to the level peculiar to the metal, greatly improving the power density of the electric double layer capacitor.

In the second aspect of the present invention, laser welding (laser beam welding) results in complete welding between the electrodes, deep penetration, and a connection portion excellent in strength is obtained.
The power density of the electric double layer capacitor can be significantly improved.

According to the third aspect of the present invention, TIG welding has good heat concentration and little distortion, so that the rivet connection before TIG welding makes the weld end surfaces (thickness surfaces) uniform.
Good welds are easily obtained. In addition, the complete welded portion of TIG welding ensures good electrical conductivity between the electrodes, and the rivet connection can increase the strength of the connecting portion between the electrodes.

In the fourth invention, the same operation and effect as those of the third invention can be obtained by combining the rivet connection and the spot welding.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates a first embodiment, in which a required number of electric double layer capacitors (single cells) 10 constituting an electric double layer capacitor (capacitor module) having a predetermined capacity are formed. Of these, for convenience of illustration, a pair of two electric double layer capacitors 10 connected in parallel (a part of a capacitor module) is shown. In an actual capacitor module, one set of two electric double layer capacitors 10 are connected in parallel, and these sets are connected in series.

Reference numeral 11 denotes an electrode (a pair of cell terminals) of the electric double layer capacitor 10, and each electrode 11a, 11b is formed of aluminum in a short shape. In the illustrated case, between the two electric double layer capacitors 10, the cell terminals 11a, 11a, 11b, 11b having the same polarities are connected to each other. These connecting portions are bent in an L shape toward the other side so that the tip ends of the electrodes 11 overlap each other, and the overlapping plate thicknesses are TIG (Tungsten) from both sides in the plate width direction.
Inert Gas) Welded by welding.

TIG welding is arc welding performed in an atmosphere of an inert gas (for example, argon gas), and since the welded portion is shielded from the air by the inert gas (Inert Gas), the alloy component of the filler metal is used. The welding efficiency of is close to 100%, and the complete welded portion 12 of good weld metal can be obtained. When argon gas is used as the inert gas, argon ions also have the effect of removing oxides on the surface of the weld (cleaning action).

As a result, the electric resistance between the electrodes 11 is lowered to a value level peculiar to the metal, and the output density of the electric double layer capacitor can be greatly improved. In other words, it becomes possible to form a high-performance capacitor module that faithfully reflects the performance from the high-performance electric double layer capacitor 10.

FIG. 2 illustrates a second embodiment, in which a pair of two electric double layer capacitors 10 connected in parallel (constituting a part of a capacitor module) are connected to each other. Cell terminals 11a, 11 of the same pole
The connecting portions connecting a, 11b, and 11b are bent in the L-shape in the same direction (parallel to each other) so that the tip ends of the electrodes 11 are bent toward each other in an L-shape and further form abutting parts. To be Then, the welded portion 12 is formed by TIG welding between the tips (plate thickness) of these overlapping butting portions.
Is generated.

According to this, since the tip of the abutting portion is a welded portion, TIG welding can be performed easily and appropriately without being interfered by the cell terminals 11 (connection portions between electrodes) of the other same polarity. .

Laser (laser beam) welding may be used as an alternative to TIG welding for joining the electrodes 11. Laser welding is a method of irradiating a laser beam and welding with the light energy, and a perfect welded portion (12 in FIGS. 1 and 2) is accurately formed between the electrodes 11, and the penetration can be set deep. Thus, a junction having excellent strength can be obtained, and the output density of the electric double layer capacitor can be significantly improved.

FIG. 3 illustrates a third embodiment, in which a pair of two electric double layer capacitors 10 connected in parallel (constituting a part of a capacitor module) are connected to each other. The connecting portions connecting the cell terminals 11 of the same pole are the same (parallel to each other) so that the tip ends of the electrodes 11 are bent in L-shapes toward each other as in FIG. It can be bent in an L shape in any direction.

The abutting portions between the electrodes 11 are joined by rivets 13 that are placed in the plate thickness direction. Further, the tips (plate thickness) of these abutting portions are welded by TIG welding.

According to this, in TIG welding, heat concentration is good and distortion is little generated. Therefore, by setting a rivet and temporarily tightening the electrodes 11 before TIG welding,
These weld end faces (plate thickness faces) are aligned, and TIG welding can be easily and accurately processed. Further, the complete welded portion 12 of the TIG welding ensures good electrical conductivity between the electrodes 11, while the rivet connection improves the strength of the connection portion between the electrodes 11 (reinforcing effect of the welded portion 12 by TIG welding). can get.

In FIG. 1, a TIG is used for joining the electrodes 11.
Spot welding may be used as an alternative to welding. In that case, the overlapping tip ends of the electrodes 11 are sandwiched by the welding electrodes from the plate thickness direction, and these plate thicknesses are welded by spot welding. Further, by combining rivet connection and spot welding, the same action and effect as in the case of FIG. 3 can be obtained.

The electric double layer capacitor 10 shown in FIGS. 1 to 3 is constructed in the same laminated body as in the case of FIG. 4, the same poles of the lead portions are bundled, and the electrodes having polarities corresponding to the bundled portions are formed. 11a and 11b are joined. The laminated body is housed in the container 10a together with the electrolytic solution and sealed in a vacuum state.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating a joint portion between electrodes (cell terminals).

FIG. 2 is a perspective view illustrating a joint between electrodes (cell terminals).

FIG. 3 is a perspective view illustrating a joint portion between electrodes (cell terminals).

FIG. 4 is an explanatory diagram of an electric double layer capacitor (capacitor module).

FIG. 5 is a cross-sectional view illustrating a joint portion between electrodes (cell terminals).

FIG. 6 is a view on arrow B of FIG.

[Explanation of symbols]

10 Electric Double Layer Capacitor (Capacitor Cell) 10a container 11, 11a, 11b Electrodes (cell terminals) 12 Welded part 13 rivets

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahisa Horie             1-chome Ichichome, Ageo City, Saitama NISSAN DI             Within Hazel Industry Co., Ltd.

Claims (4)

[Claims] 1. From the required number of electric double layer capacitor cells, 1
In the electric double layer capacitor composed of two modules, the connecting portion connecting the electrodes of the electric double layer capacitor cells is formed by stacking the plate-shaped electrodes and welding the plate thicknesses by TIG welding. An electric double layer capacitor characterized in that. 2. One out of a required number of electric double layer capacitor cells.
In the electric double layer capacitor composed of two modules, the connection part that connects the electrodes of the electric double layer capacitor cells is made by stacking plate-shaped electrodes and welding them by laser welding. An electric double layer capacitor characterized in that. 3. From the required number of electric double layer capacitor cells, 1
In the electric double layer capacitor composed of two modules, the connection part that connects the electrodes of the electric double layer capacitor cells is made by stacking the plate-shaped electrodes together and adding the rivet connection between these plate thicknesses. , TIG
An electric double layer capacitor characterized by being welded. 4. One out of a required number of electric double layer capacitor cells.
In the electric double layer capacitor composed of two modules, the connection part that connects the electrodes of the electric double layer capacitor cells is made by stacking the plate-shaped electrodes together and adding the rivet connection between these plate thicknesses. An electric double layer capacitor characterized by being welded by spot welding.