JPS61207010A - Electric double-layer capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to improvements in electric double layer capacitors.

(Prior Art) FIG. 2 is a sectional view showing an example of a conventional electric double layer capacitor. In this figure, a pair of gaskets 1.2 containing polarizable electrodes 5.6 in each cavity 3.4 are glued together via a separator 7 that is permeable to ions and has electrical insulation properties. A conductive sheet 8.9 is attached to a gasket 1
．． The polarizable electrode 5.6 is placed on the outer surface of the electrode 2 and bonded so as to close the space 3.4 housing the polarizable electrode 5.6.

The polarizable electrode 5.6 is made of, for example, a mixed paste of activated carbon powder and an electrolyte solution made of sulfuric acid or the like. Therefore, although the space 3.4 of the gasket 1.2 is filled with paste, it has the following problems.

In other words, variations in capacity occur due to increases and decreases in the paste filling ω. In addition, because we handle paste-like materials,
When filling the gasket 1.2, there is a problem in that the paste overflows from the cavity 3.4 and contaminates the surrounding area. moreover,
If paste leaks, it cannot be completely sealed with the conductive sheet 8.9, resulting in poor characteristics.

In order to solve this problem, the inventors proposed that the polarizable electrode be made into a solid form instead of a paste form. In other words, we proposed that the polarizable electrode be composed of a mixed molded body of carbon-based powder and a caking material.

Specifically, it is a mixture of carbon-based powder, such as activated carbon powder, and an emulsion, and the following method was adopted to obtain this mixed molded body. First, a dispersed activated carbon powder dispersed in a solvent and a dispersed latex dispersed in a solvent are mixed.

Next, the solvent is removed from the mixed solution to obtain a mixture in an aggregated state. Furthermore, this mixture is once pulverized, and the pulverized product is granulated. Thereafter, a mixed molded body is obtained by pressing the granulated powder using a press or the like.

By impregnating this mixed molded body with an electrolyte solution, it can be used as a polarizable electrode.

The polarizable electrode made of this mixed molded body will be housed in the cavity 3.4 of the gasket 1.2, similar to the electric double layer capacitor shown in Fig. 2, and the structure will be as shown in Fig. 2. It never changes.

(Problem to be Solved by the Invention) However, in an electric double layer capacitor having such a configuration, the mixed molded body is impregnated with an electrolyte solution to form the polarizable electrode, but the electrolyte solution is impregnated into the inside of the mixed molded body. It took some time to get it done. In addition, the polarizable electrode is housed in the gasket so that it almost occupies the space, but if a voltage higher than the withstand voltage is applied to the electric double layer capacitor in this state, it will break due to the presence of the electrolyte solution. Electrolysis takes place, and as a result, gas is generated within the cavity of the gasket, and the internal pressure is increased by the gas pressure within the cavity, resulting in a decrease in the degree of adhesion between the polarizable electrode and the conductive sheet, etc. This works to increase the individual series resistances (E, S, R).

(Objective of the Invention) Therefore, an object of the present invention is to provide an electric double layer capacitor free from the above-mentioned problems.

Specifically, we aim to provide an electric double layer capacitor that has a structure that accelerates the impregnation of an electrolyte solution when forming a polarizable electrode, and that can be put to practical use even when a voltage higher than the withstand voltage is applied. purpose.

(Means for Solving the Problems) That is, the gist of the present invention is that a pair of polarizable electrodes surrounded by an insulating member are disposed with a porous separator having ion permeability interposed therebetween; An electric double layer capacitor consisting of a conductive sheet bonded to the outer surface of a polarizable electrode, the polarizable electrode having a solid carbonaceous molded body as its main body and impregnated with an electrolyte solution. , the polarizable electrode has a partially missing portion, and the missing portion forms a void region inside the insulating member.

Further, in the electric double layer capacitor according to the present invention, a region where no liquid column of electrolyte solution exists is formed in the porous separator having ion permeability, and the region is made to correspond to the void region formed by the polarizable electrode. It also includes structures.

In this case, since the region of the porous separator where no liquid column exists does not come into contact with the polarizable electrodes, there is no fear that the polarizable electrodes will come into contact with each other via the separator and cause an electrical short circuit.

Note that the area where the liquid column of electrolyte solution formed on the separator does not exist means, for example, an artificially formed through hole or a porous part of a porous separator. A region that does not exist from one surface to the other.

(Function) In the present invention, the polarizable electrode has a solid carbonaceous molded body as its main body and is impregnated with an electrolyte solution, and the polarizable electrode has a partially missing portion, Since this defective part forms a void area inside the insulating member, the apparent surface area of the polarizable electrode itself increases, which allows the electrolyte solution to sufficiently penetrate into the solid carbonaceous molded body. At the same time, gas generated when a voltage higher than the withstand voltage is applied exists in the void region, and this void region acts as a buffer space, increasing the gas pressure inside the insulating member and increasing the degree of adhesion between the polarizable electrode and the conductive sheet. will not be damaged.

(Embodiments) The present invention will be described in detail below according to illustrated embodiments.

FIG. 1 shows an embodiment of the present invention, in which 11.12 is an insulating member, that is, a gasket, having a cavity 13.14, and the cavity 13.14 is a solid carbonaceous material impregnated with an electrolyte solution. Polarizable electrodes 15, 16 made of molded bodies are accommodated. A through hole 17.18 is formed in the center of the polarizable electrode 15.16, and the through hole 17.18 is a partially missing portion. This through hole 17.18 forms a void area inside the cavity 13.14 of the gasket 11.12. These pair of gaskets 11 and 12 are disposed, specifically bonded, with an ion-permeable and electrically insulating porous separator 19 interposed therebetween. The separator 19
For example, it is constructed using a nonwoven fabric made of polyolefin such as polyethylene or polypropylene, or cellulose for paper making such as kraft paper or manila paper.

Here the separator 19 is in contact with the polarizable electrode 15.16.

A conductive sheet 20.21 is bonded to the outer surface of the gasket 11.12 and the polarizable electrode 15.16 so as to enclose the polarizable electrode 15.16.

The solid carbonaceous molded body constituting the main body of the polarizable electrodes 15 and 16 can be the one described in the conventional technology section, or carbonaceous powder molded into a sheet shape, or fibers. Including activated carbon cloth etc.

Further, as shown in FIG. 3, the solid carbonaceous molded body constituting the main body of the polarizable electrode 1/5.16 has recesses 17a and 18a formed in a part of the disk, for example, and the gasket 11.
It may be configured such that a void area is formed inside the twelve voids 13,14. Of course, the solid carbonaceous molded body shown in FIG. 3 is impregnated with the electrolyte solution while being housed in the gasket 11, 12.

According to this embodiment, therefore, polarizable electrode 15.1
The apparent surface area of the solid carbonaceous molded body itself that constitutes the main body of No. 6 increases, thereby increasing the contact area with the electrolyte solution, so that the electrolyte solution penetrates evenly and satisfactorily impregnates the inside. It turns out. In addition, since the polarizable electrodes 15.16 have a missing portion 17.18, this missing portion 11.18 causes the gasket 1, which is an insulating member, to
A void area is formed in the cavity 13.14 of 1.12. Therefore, even if the electrolyte solution is electrolyzed and generates gas when a voltage higher than the withstand voltage is applied, the gas will be taken into this void area, increasing the gas pressure in the voids of the gaskets 11 and 12, and causing polarization. There is no reduction in the degree of contact between the electrodes 15 and 16 and the conductive sheet 20, and
There is still sufficient contact and the equivalent series resistance (E, S
, R,).

FIG. 4 is a sectional view showing another embodiment of the invention.

The electric double layer capacitor shown in FIG. 4 is characterized by the through hole 22 in the separator 19 of the electric double layer capacitor shown in FIG.
was formed.

This through hole 22 becomes a region where no electrolyte solution exists, that is, a region where no liquid column exists from one surface to the other surface of the separator 19. The size of the through hole 19 depends on the thickness and external size of the separator 19, but
For example, the size is selected within the range of 0.2 to 0.5 nmφ. In addition to this, although not shown, there is a porous region that does not have an affinity for the electrolyte solution present in the separator, as an area where no liquid column exists.

The through hole 22 corresponds to the position of the through hole 11.18 of the polarizable electrode 15.16, as is clear from the illustrated state. In this case, the polarizable electrodes 15, 16 and the through holes 22 are not in contact with each other. Therefore, separator 1
A situation in which the polarizable electrodes 15, 16 are in electrical contact with each other via 9 is avoided.

In addition, when the polarizable electrodes 15, 16 shown in FIG. 3 are used, the through holes 22 of the separator 19 may be formed to correspond to the respective missing portions 17a, 18a, here the recesses. Of course, these recesses 17a and 18
a is not in contact with the through hole 22.

The electric double layer capacitor having such a structure produces the same effects as shown in FIG. 1, and also has the following advantages.

FIG. 5 shows the structure of the electric double layer capacitor shown in FIG. 4 before it is completed.

That is, this is the state before the polarizable electrode 17 is accommodated in the cavity 13 of the gasket 11. During this state, the electrolyte solution 23 is dripped into the cavity 13. Next, the conductive sheet 21 is displaced in the direction of the arrow by, for example, a negative pressure source (not shown). At this stage, most of the electrolyte solution 23 on the separator 19 is introduced into the cavity 14 of the gasket 12 through the through hole 22 . Then, the polarizable electrode 16 is impregnated with the electrolyte solution 23 while the conductive sheet 21 is kept displaced downward by the negative pressure source for a while. After impregnation, the displacement of the conductive sheet 21 by the negative pressure source is released. Next, although not shown, a polarizable electrode is housed in the cavity 13 of the gasket 11, and the polarizable electrode is impregnated with an electrolyte solution. This electrolyte solution may be dropped onto the polarizable electrode, and the dropped electrolyte solution penetrates into the interior due to capillary action. Although there is a problem with the rate of impregnation of the electrolyte solution with this polarizable electrode, it is also possible to use an electrode that does not have through holes 18 like the polarizable electrode 16.

Next, a conductive sheet (not shown) is bonded to the outer surface of the gasket 11 so as to confine the polarizable electrode in the space 13.

According to this method, the solid carbonaceous molded body that becomes the polarizable electrode can be handled without being impregnated with an electrolyte solution, and the polarizable electrode can be easily handled in the manufacturing process. Furthermore, when handling polarizable electrodes that have been pre-impregnated with an electrolyte solution as in the past, the process of bonding the conductive sheet to the gasket is performed under reduced pressure, which can easily cause liquid leakage and sealing failure. According to this method, one of the polarizable electrodes is stored in the cavity of the gasket in the form of a dry solid carbonaceous molded body, so the conductive sheet can be bonded under atmospheric pressure and in a dry state. ,
This step can prevent sealing defects from occurring.

(Effects) According to the electric double layer capacitor according to the present invention, the polarizable electrode is composed of a solid carbonaceous molded body impregnated with an electrolyte solution; The polar electrode has a partially missing portion such as a through hole or a recess, and this missing portion forms a void area within the cavity of the gasket. Therefore, the apparent surface area of the polarizable electrode itself increases, and as a result, the electrolyte solution penetrates quickly and sufficiently into the interior. In addition, since a void region is formed in the cavity of the gasket, the gas generated when a voltage higher than the withstand voltage is applied is taken into this void region, increasing the internal pressure within the gasket and polarizing the electrode. This does not impair the degree of adhesion between the conductive sheet and the conductive sheet, and there is no risk of increasing the equivalent series resistance (E, S, R).

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electric double layer capacitor according to the present invention. FIG. 2 is a sectional view showing a conventional electric double layer capacitor. FIG. 3 is a sectional view of a solid carbonaceous molded body constituting the main body of the polarizable electrode. FIG. 4 is a sectional view showing another embodiment of the electric double layer capacitor according to the present invention. FIG. 5 is a sectional view showing the structure of the electric double layer capacitor shown in FIG. 4 during the manufacturing process. 111.12 is a gasket, 13.14 is a void, 15.
16 is a polarizable electrode, 17.18 is a through hole, 19 is a separator, and 20.21 is a conductive sheet. 1. Indication of the case 1985 Patent Application No. 48665 2. Title of the invention 7. Electric double layer capacitor 3. Case of the person making the amendment Relationship Patent applicant address 2-26-10 Tenjin, Nagaokakyo City, Kyoto Name (
623) Mura Co., Ltd. 1) Manufactured in 1985 6
May 25th, 5th, No number of inventions increased due to amendment 6, Subject of amendment Book III 1, Contents of amendment As per the engraving of the specification and attached sheet originally attached to the application.
(No change in content)

Claims (3)

[Claims] (1) A pair of polarizable electrodes surrounded by an insulating member are arranged through a porous separator having ion permeability, and a conductive sheet is bonded to the outer surface of each polarizable electrode, In an electric double layer capacitor in which the polarizable electrode has a solid carbonaceous molded body as its main body and is impregnated with an electrolyte solution, the polarizable electrode has a partially defective portion, and the defect is An electric double layer capacitor characterized in that a void region is formed inside an insulating member by a portion of the insulating member. (2) The porous separator having ion permeability is
The electric double layer capacitor according to claim 1, which has a region in which no liquid column of electrolyte solution exists, and the region corresponds to a void region formed by the polarizable electrode. (3) The electric double layer capacitor according to claim (2), wherein the region where the liquid column of the electrolyte solution does not exist is a through hole.