JPH05326326A - Electric double layer capacitor and its manufacture - Google Patents

Abstract

PURPOSE:To provide an electric double layer capacitor low in inner resistance and its manufacture by making the contact resistance between a collector and a polarizing electrode extremely small. CONSTITUTION:An electric double layer capacitor is gotten, which comprises an electrode 1 consisting of the structure including the gradient material consisting of a collector material and a polarizing electrode material, a separator 2, a gasket 3, and electrolyte. Moreover, the electrode 1 consists of the structure where the collector material and the polarizing electrode material are stacked and pressed in a body and then are sintered.

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 having a reduced internal resistance and a method for manufacturing the same.

[0002]

2. Description of the Related Art An electric double layer capacitor utilizes electric energy accumulated in an electric double layer formed at an interface between activated carbon and an electrolytic solution, and has a large capacity capable of instantaneously charging and discharging the electric capacity of farad order. It is a capacitor.

Heretofore, as the polarizable electrode of the electric double layer capacitor, powdered activated carbon which has been pressure-molded with an aqueous solution of sulfuric acid, activated carbon fiber cloth having a metal sprayed layer formed on one surface, and the like have been used. In addition, in order to improve the capacity density per unit volume of the capacitor, it has been proposed to sinter the polarizable electrode into a solid plate shape. An example of an electric double layer capacitor using a solid polarizable electrode to reduce the internal resistance is shown in FIG. 3 (Japanese Patent Laid-Open No. 80517). 7 is a plate-shaped current collector obtained by press-sintering conductive powder such as activated carbon powder or carbon black powder to densify, and 8 is one surface of the current collector impregnated with an electrolytic solution such as dilute sulfuric acid. A polarizable electrode formed by sintering activated carbon powder is integrally formed, a separator 9 and a gasket 10.

[0004]

In such a conventional electric double layer capacitor, a plate-shaped current collector is press-sintered and a polarizable electrode is sinter-molded on the current collector. Therefore, an interface exists between the plate-shaped current collector and the polarizable electrode, and the contact resistance is large. Therefore, the electric double layer capacitor using the electrode body formed of the plate-shaped current collector and the polarizable electrode has a problem of high internal resistance.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electric double layer capacitor having a low contact resistance between a current collector and a polarizable electrode and a low internal resistance, and a method for manufacturing the same. I am trying.

[0006]

In order to achieve the above object, the present invention uses a structure including a gradient material composed of a current collector material and a polarizable electrode material. That is, in the electrode body, the composition of activated carbon is increased from the side of the current collector toward the polarizable electrode.

As a manufacturing method thereof, 100 to 0% of a current collector material and 0 to 100% of a polarizable electrode material are similarly included from one surface toward the other surface, and both material compositions are provided between both surfaces. A structure including a graded material that changes stepwise or continuously is used, or a stack of a current collector and a material for a polarizable electrode is used.

[0008]

According to the present invention, since the electrode body is the gradient material body of the current collector and the polarizable electrode according to the above-mentioned constitution, the current collector and the polarizable electrode are continuous in the electrode body, and The contact resistance between the electric body and the polarizable electrode can be made extremely small. Therefore, the internal resistance of the electric double layer capacitor can be reduced by using the electrode body.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

(Example 1) As a current collector material, a powder (hereinafter referred to as a current collector material) in which graphite powder and a non-novolak or non-resole type phenol resin were mixed at a weight ratio of 7: 3 was prepared. To do. As the polarizable electrode material, a powder (hereinafter referred to as a polarizable electrode material) in which a phenol resin-based activated carbon and a non-novolak or non-resol type phenol resin are mixed at a weight ratio of 7: 3 is prepared. Next, the current collector material and the polarizable electrode material are mixed in a weight ratio (a) of 10: 0, (b).
8: 2, (c) 6: 4, (d) 4: 6, (e) 2: 8,
(F) The ingredients are mixed at 0:10, and these are sequentially laminated in a press die with a predetermined thickness from (a) to (f). Press the laminated current collector material and polarizable electrode material at a pressing temperature of 120-2.
Press molding is carried out at 00 ° C. and a pressing pressure of 100-400 kg / cm ² . The molded body obtained by press molding in this manner was sintered at 600 to 1000 ° C. in an inert atmosphere to form an electrode body.

In this electrode body, the current collector and the polarizable electrode are continuous, and the contact resistance between the current collector and the polarizable electrode is extremely small.

This electrode body was impregnated with 30% by weight of sulfuric acid as an electrolytic solution, and a separator and a gasket were used to manufacture an electric double layer capacitor having the shape shown in FIG. In FIG. 1, 1 is an electrode body. The separator side of the electrode body has a very large specific surface area because of the large amount of activated carbon, and the opposite side has a very low electric resistance because of the large amount of graphite. Again 2
Is a separator and 3 is a gasket.

Although graphite powder is used as the material of the current collector, it is not limited to this as long as it is a substance having conductivity after sintering, and non-novolak and non-resole type phenol resins are also cured. It is not limited to this as long as it is a thermosetting binder that melts at a temperature equal to or lower than the temperature.

Although phenolic resin-based activated carbon was used as the material of the polarizable electrode, it is not limited to this as long as it is activated carbon, and non-novolak and non-resole type phenolic resins are melted at a temperature below the curing temperature. The thermosetting binder is not limited to this.

Although sulfuric acid of 30% by weight was used as the electrolytic solution, the electrolytic solution is not limited to this.

Although a polypropylene porous film is used as the separator, it is not limited to this as long as it is non-electroconductive and ion-permeable.

The internal resistance of the electric double layer capacitor according to the present embodiment and the internal resistance of the conventional electric double layer capacitor are shown in comparison with each other (Table 1). As a conventional example, the same electrolytic solution and separator as in Example 1 were used with the configuration shown in FIG.

As is clear from this (Table 1), according to this embodiment, the internal resistance can be reduced as compared with the conventional example.

[0019]

[Table 1]

(Embodiment 2) In FIG. 2, the composite electrode material body 4 is composed of a current collector portion 4a and a polarizable electrode portion 4b. A powder obtained by mixing graphite powder, a non-novolak, and a non-resole type resin in a weight ratio of 7: 3 as a material for the current collector part, and a phenol resin-based activated carbon, a non-novolac, and a non-resole type phenol resin as a material for the polarizable electrode part. And a powder mixture of and in a weight ratio of 7: 3 are laminated. The laminated collector material and the polarizable electrode material are pressed at a pressing temperature of 120-
Simultaneous press molding is performed at 200 ° C. and a pressing pressure of 100 to 400 kg / cm ² . Press-molded product in an inert atmosphere 6
The composite material electrode body 4 was formed by sintering at 00 to 1000 ° C.

The composite material electrode body 4 has an electrolyte solution of 30
An electric double layer capacitor was manufactured by impregnating a large amount of sulfuric acid and using the separator 5 and the gasket 6.

The internal resistance of the electric double layer capacitor according to this embodiment and the internal resistance of the conventional electric double layer capacitor are shown in comparison with each other (Table 2). As a conventional example, the same electrolytic solution and separator as in Example 1 were used with the configuration shown in FIG.

As is clear from this (Table 2), according to this embodiment, the internal resistance can be reduced as compared with the conventional example.

[0024]

[Table 2]

The current collector, the polarizable electrode, the electrolytic solution,
The separator, the gasket, etc. are the same as those in the first embodiment and are not limited to these.

[0026]

As is apparent from the above description, according to the present invention, a structure including a gradient material composed of a current collector material and a polarizable electrode material is used, and the structure is divided from the current collector side in the electrode body. The current collector and the polarizable electrode are continuous in the electrode body by increasing the composition of the activated carbon toward the polar electrode, and the contact resistance between the current collector and the polarizable electrode is extremely high. Can be made smaller. Therefore, the internal resistance of the electric double layer capacitor can be reduced by using the electrode body.

As a manufacturing method thereof, 100 to 0% of a current collector material and 0 to 100% of a polarizable electrode material are also included from one surface toward the other surface, and both material compositions are provided between both surfaces. By using a structure containing a graded material that changes stepwise or continuously, or by using a laminate of a current collector and a material for a polarizable electrode, the above structure can be easily and efficiently manufactured. it can.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the internal structure of an electric double layer capacitor according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing the internal structure of an electric double layer capacitor of another embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view showing the internal structure of a conventional electric double layer capacitor.

[Explanation of symbols]

1 Electrode body having a structure including a gradient material composed of a current collector material and a polarizable electrode material 2 Separator 3 Gasket 4 Composite material electrode body 4a Current collector part 4b Polar electrode part 5 Separator 6 Gasket 7 Current collector 8 min Polar electrode 9 Separator 10 Gasket

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Nonaka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. An electric double layer capacitor composed of an electrode body composed of a current collector and a polarizable electrode, a separator, and an electrolytic solution, wherein the electrode body is composed of the current collector and the polarizable electrode. An electric double layer capacitor, which is a structure including a graded material composed of a material. 2. The electric double layer capacitor according to claim 1, wherein the current collector material contains at least a conductive carbon material and a thermosetting resin, and the polarizable electrode material contains at least activated carbon and a thermosetting resin. .. 3. A current collector material of 100% to 0% and a polarizable electrode material of 0% to 100% from one surface to the other surface.
An electric double layer, characterized in that an electrode body, which is a structure containing a gradient material in which both material compositions change stepwise or continuously between both surfaces, is produced by integrally molding and sintering. Method of manufacturing capacitor. 4. A step of laminating a current collector and a material of a polarizable electrode, a step of press-molding the laminated current collector and a material of a polarizable electrode at the same time, and the press-molded current collector. And a step of forming a composite material electrode body by sintering the material of the polarizable electrode, a step of impregnating the composite material electrode body with an electrolytic solution, and using a composite material electrode body impregnated with the electrolytic solution, a separator and a gasket And a step of assembling the electric double layer capacitor. 5. The electric double layer capacitor according to claim 1, wherein the electrode body has airtightness.