JP2001185452A - Electric double layer capacitor and its method of manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric double layer capacitor that has a smaller internal resistance and a higher electrostatic capacity. SOLUTION: This capacitor comprises a pair of collectors 4a, 4b forming a positive electrode and a negative electrode, polarizable electrodes 2a, 2b forming the positive electrode and the negative electrode that contain activated carbon laminated on a front face of each collector 4a, 4b, a separator 3 that is interposed between polarizable electrodes 2a, 2b forming the positive electrode and the negative electrode, and an electrolyte which is impregnated the polarizable electrode 2 and separator 3. In addition, the polarizable electrodes 2a, 2b and collectors 4a, 4b forming the positive electrode and the negative electrode are integrated by sintering respectively.

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 small internal resistance and a large capacitance and a method for manufacturing the same.

[0002]

2. Description of the Related Art Recently, an electric double layer capacitor capable of charging and discharging a large current has been receiving attention. An electric double layer capacitor is a capacitor that uses an electric double layer formed by the polarization of ions at the interface between the electrode and the electrolyte, and can charge a large capacitance compared to conventional capacitors, and can rapidly charge and discharge. Is possible and its application is expected.

[0003] Generally, the structure of an electric double layer capacitor is as follows.
For example, a plurality of polarizable electrodes forming a positive electrode and a negative electrode impregnated with an electrolytic solution containing activated carbon via an insulating separator are stacked, and further charged and discharged through a current collector of the positive electrode and the negative electrode stacked on both surfaces thereof Thereby, a capacitance can be generated inside the polarizable electrode.

In such an electric double layer capacitor,
High capacity and high discharge density are required, but if the internal resistance of the capacitor is high, the voltage drops sharply at the beginning of discharge as the current density increases, so-called IR drop is seen, so the internal resistance of the capacitor is reduced Is required. The internal resistance is the volume specific resistance of the polarizable electrode,
This is due to the pore distribution state, the ionic conductivity of the electrolytic solution, the contact resistance between the polarizable electrode and the current collector, etc., but especially when the contact state between the polarizable electrode and the current collector is poor. It is known that the resistance increases.

Conventionally, as a method of reducing the contact resistance between the polarizable electrode and the current collector, a method of providing a spring or a pressure plate and caulking, or a method of forming an organic layer such as PTFE or polypropylene between the polarizable electrode and the current collector. A method of bonding with a resin adhesive, and a method of forming the current collector on the surface of the polarizable electrode by thermal spraying are known.

[0006]

However, in the method of providing the spring and the pressure plate and caulking, the members such as the spring and the pressure plate are separately required, and the size and weight of the electric double layer capacitor cannot be reduced. . In the method of bonding the polarizable electrode and the current collector with an adhesive made of an organic resin, the adhesion between the polarizable electrode and the current collector is improved, but the contact at the adhesive portion is high because the resistance is high. The resistance could not be reduced sufficiently. Further, in the method in which the current collector is applied to the surface of the polarizable electrode by thermal spraying, the surface of the polarizable electrode may be deteriorated, and the effect of reducing the contact resistance is not sufficient. There was a problem that was large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to produce an electric double layer capacitor having a small internal resistance and a large capacitance, and a method of manufacturing the same.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned problems, and as a result, by integrally forming the polarizable electrode and the current collector by sintering, the polarizable electrode and the current collector were formed. It has been found that the contact resistance with the body can be reduced, the internal resistance can be reduced, and the capacitance can be increased.

That is, the electric double layer capacitor of the present invention comprises: a pair of current collectors forming a positive electrode and a negative electrode; and a polarizable electrode forming an active carbon-containing positive electrode and a negative electrode laminated on the surfaces of the respective current collectors. And a separator interposed between the polarizable electrode forming the positive electrode and the negative electrode, wherein the polarizable electrode forming the positive electrode and the negative electrode and the current collector are integrally formed by sintering, respectively. It is characterized by becoming.

Here, the current collector on the positive electrode side is Al, T
i, Ta, Ag, Nb, Pt, Au, and at least one metal selected from the group consisting of Cu, Ag, Ni, Pt, and Au, wherein the current collector on the negative electrode side is at least one metal selected from the group consisting of Cu, Ag, Ni, Pt, and Au. It is preferable that the oxygen content of the activated carbon in the polarizable electrode on the positive electrode side is larger than the oxygen content of the activated carbon in the polarizable electrode on the negative electrode side.

Further, the method for producing an electric double layer capacitor according to the present invention comprises the steps of preparing a sheet-like activated carbonaceous molded article for a positive electrode and a negative electrode containing activated carbon powder, and one of the activated carbonaceous molded articles. A step of laminating a conductor layer for a current collector of a positive electrode or a negative electrode on the surface, and heat treatment and sintering each of the molded bodies laminated with the conductor layer at a temperature equal to or lower than the melting point of the conductor layer. And forming the current collector integrally, and disposing the integrated body of the activated carbonaceous structure for the positive electrode and the negative electrode and the current collector such that the activated carbonaceous structure side faces each other; A step of laminating a separator between the activated carbonaceous structure surfaces, and a step of filling the activated carbonaceous structure and the separator with an electrolytic solution to form polarizable electrodes and separators of a positive electrode and a negative electrode. You It is intended.

Here, it is preferable that the heat treatment temperature of the activated carbonaceous structure on the positive electrode side and the current collector be lower than the heat treatment temperature of the activated carbonaceous structure on the negative electrode side and the current collector. The current collector on the positive electrode side is made of Al, Ti, T
a, Ag, Nb, Pt, and at least one metal selected from the group consisting of Au, and the current collector on the negative electrode side is at least one metal selected from the group consisting of Cu, Ag, Ni, Pt, and Au. Further, it is preferable that the oxygen content of the activated carbon in the polarizable electrode on the positive electrode side is larger than the oxygen content of the activated carbon in the polarizable electrode on the negative electrode side.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the electric double layer capacitor of the present invention will be described with reference to a schematic sectional view of FIG. 1A and a partial plan view of FIG. According to FIG. 1A, an electric double layer capacitor 1 is insulated between two polarizable electrodes (hereinafter abbreviated as electrodes) 2a and 2b for a positive electrode and a negative electrode containing activated carbon impregnated with an electrolytic solution. Porous separator (hereinafter, abbreviated as separator) 3 is formed. In addition, positive electrode and negative electrode current collectors 4a and 4b are formed on the surfaces of the positive electrode and negative electrode 2a and 2b, respectively. Further, according to FIG. 1A, current collector 4a-electrode 2a-separator 3 -Electrode 2b-Laminated body 6 of current collector 4b
A sealing material 5 is formed on the outer peripheral surfaces of the electrodes 2a and 2b laminated on the upper and lower surfaces, respectively, and the laminate 6 and the electrodes 2a and 2b are sealed from the outside by the sealing material 5.

According to the present invention, it is a great feature that the electrodes 2a and 2b are formed integrally with the current collectors 4a and 4b by sintering, thereby forming the electrode 2a and the current collector 4a. The internal resistance can be reduced by reducing the contact resistance between the electrodes 2b and the current collector 4b.

The electrode 2 is composed of activated carbon particles having a high specific surface area and a carbon component blended for binding between the activated carbon particles. In order to increase the strength of the structure, the activated carbon particles are used. The organic binder component may remain in the porous structure after firing. Further, in order to obtain a strength that does not hinder handling as a structure while maintaining a high capacitance, the specific surface area of the electrode 2 is set to 1000 to 30.
It is desirably about 00 m ² / g.

Further, the oxygen content of the activated carbon in the electrode 2 is mainly determined by -OH (phenol group),-
These are caused by functional groups such as COOH (carboxyl group) and -CHO (aldehyde group). However, when a voltage of 2.5 V or more is applied, the functional group on the surface of the activated carbon is not charged in the electric double layer capacitor at the negative electrode side. As a result of an oxidation or reduction reaction with water present in the active carbonaceous structure, the functional group in the activated carbonaceous structure is reduced to generate gas such as carbon dioxide gas and oxygen gas and other impurities, and the impurities adhere to the activated carbon surface, In addition to hindering ion adsorption, weakening the bonding force between the particles in the activated carbonaceous structure, increasing the internal resistance, and reducing the shape retention of the activated carbonaceous structure, the functionalities of the activated carbon surface of the negative electrode 2b are reduced. It is desirable that the amount of base is small, that is, the amount of oxygen of activated carbon in the negative electrode 2b is small.

Since the positive electrode side preferably has a large amount of functional groups on the surface of the activated carbon in order to increase the capacitance, that is, it is desirable that the amount of oxygen in the activated carbon is large, the oxygen content of the activated carbon of the electrode 2a on the positive electrode side is reduced. It is preferable that the oxygen content of the activated carbon in the side electrode 2b is larger than that of the activated carbon.

The carbon component added as a binder is present between the activated carbon particles and serves to enhance the sinterability and bonding between the activated carbon particles. However, in order to increase the specific surface area of the electrode 2, the carbon component is added. It is desirable that the amount of the component is small, and it is desirable that the proportion in each activated carbonaceous structure is 5 to 50% by weight.

The electrode 2 preferably has a plate shape such as a circular or rectangular surface, and the strength of the activated carbonaceous structure preferably has a three-point bending strength of 30 kPa or more, particularly 60 kPa or more.

The electrolytic solution impregnated in the electrode 2 includes an aqueous solution of sulfuric acid or nitric acid, propylene carbonate, γ-
An organic solution obtained by combining an organic solvent such as butyrolactone, N, N-dimethylformamide, ethylene carbonate, sulfolane, and 3-methylsulfolane with an electrolyte such as a quaternary ammonium salt, a quaternary sulfonium salt, and a quaternary phosphonium salt can be used. However, according to the present invention, in particular, an organic electrolytic solution capable of increasing the withstand voltage to 2.5 V or more,
It is particularly effective for those using propylene carbonate as a solvent.

The separator 3 is formed to insulate between the electrodes 2a and 2b for the positive electrode and the negative electrode, and is capable of transmitting ions in the electrolyte contained in the electrode 2. Formed of a porous body. As the separator 3, specifically, electrolytic paper, polyethylene nonwoven fabric, polypropylene nonwoven fabric, polyester nonwoven fabric,
Kraft paper, Manila hemp sheet, glass fiber sheet, porous ceramic sintered body and the like can be used.

As shown in the plan view of the laminated body 6 in FIG. 1B, the separator 3 is provided with an electrode 2 and a current collector to enhance the insulation between the positive and negative electrodes 2a and 2b. Separator 3 which is larger than 4 and is planar
Is desirably formed so that the periphery of the electrode 2 is outside the periphery of the electrode 2.

When a plurality of units of the laminated body 6 are laminated as a unit, at least the end portions of the outer peripheral portions of two adjacent separators are continuously formed. It can be substituted as a bag.

Further, it is important that the current collector 4 is made of a conductive material which can be co-fired with the activated carbonaceous structure forming the electrode 2. Further, an oxidation reaction occurs in the electric double layer capacitor on the positive electrode side. In particular, since a part of the current collector 4a on the positive electrode side may be ionized and eluted in the electrolytic solution to deteriorate the current collector 4a, particularly, the current collector 4a on the positive electrode side includes:
It is desirable that the electrode can effectively use an electrochemically stable potential region with respect to the electrolytic solution, and particularly that the electrode has a wide potential window with respect to the organic electrolytic solution. Specifically, Al, Ti,
It is preferable that the metal is at least one metal selected from the group consisting of Ta, Ag, Nb, Pt, and Au. Further, Al is most suitable as the metal on the positive electrode side in terms of low cost, light weight, and reliability.

Further, as the current collector 4b on the negative electrode side, Cu, Ag, N 2 having a high melting point are used in order to co-fire with the electrode 2 and to reduce the oxygen content of the electrode 2 as described above.
Desirably, it is made of at least one metal selected from the group consisting of i, Pt, and Au.

Here, according to FIG. 2, the current collector 4 is formed in a shape comprising a rectangular current collector A and a terminal B connected to one end of the current collector A. And the current collector portion A is smaller than the electrode 2 in plan view.
Is formed so that the periphery of the electrode 2 is inside the periphery of the electrode 2. This has the effect of increasing the ratio of the electrode 2 in the electric double layer capacitor and improving the capacitance. Note that the other end of the terminal portion B projects outside the sealing material 5 and is connected to an external circuit.

The above-mentioned current collectors 4a, 4b, electrode 2
As the sealing material 5 for sealing the laminate 6 of the separators a and 2b and the electrodes 2a and 2b formed on the upper and lower surfaces of the laminate 6, the laminate 6 and the electrodes 2a and 2b are made of a sheet such as resin or aluminum laminate. It is made of a member that can be hermetically sealed and is thin, light, and deformable.

As shown in FIG. 1, the sealing member 5 is formed by a laminate composed of two current collectors 4, two electrodes 2, and one separator 3. The present invention is not limited to this, and the number of the current collectors 4, the number of the electrodes 2, the number of the electrodes 2, and the number of the separators 3 may be two or more with the stacked body 6 as one unit.

Next, an example of a method for manufacturing the electric double layer capacitor as described above will be described. First, in order to produce a solid activated carbonaceous structure (hereinafter, abbreviated as activated carbonaceous structure) forming a polarizable electrode, a carbon raw material for producing activated carbon is prepared. Activated carbon produced by steam activation, chemical activation or gas activation for coconut shells, wood, resins, etc., which are primary raw materials, is suitable because it has a high specific surface area.Other than that, coke, carbon black,
Carbon fiber, coal and the like can be used.

As an active carbon raw material for the electrode forming the positive electrode, for example, activated carbon having a high oxygen content due to a surface functional group such as coke is used. As an active carbon raw material forming the negative electrode, for example, a coconut shell activated carbon is used. Alternatively, activated carbon having less oxygen content due to surface functional groups than positive electrode activated carbon such as phenol may be used.

The shape may be spherical, flake-like, protruding or irregular, and is not particularly limited, and may be any of powder, granule, and granule. Is preferably 5 to 50 μm. A predetermined amount of an organic binder is added to each of the above activated carbon raw materials in an amount such that the amount of the carbonaceous component after firing becomes 5 to 50% by weight,
Mix. Phenol, PTF as organic binder
E, coal tar, polyvinyl butyral (PVB),
Examples thereof include known organic binders such as polyvinyl acetal such as polyvinyl formal (PVFM) and vinyl acetate. Particularly, polyvinyl butyral (PVB) is most preferable from the viewpoint of moldability and strength of the obtained solid activated carbonaceous structure.

The obtained powder is formed into a predetermined shape by a known molding means such as a press molding method, a doctor blade method, an extrusion molding method, a calender roll method, a roll molding method and the like. As a forming method, roll forming that can easily form a sheet having high productivity and increase the density of a formed body can be suitably used.

Further, a plurality of the sheet-like activated carbonaceous structures may be laminated and adhered.
By decomposing by thermocompression bonding at 0 ° C. and 20 to 50 MPa, or by applying and bonding an adhesion liquid or an adhesive between the sheets, delamination in the heat treatment described below can be prevented.

According to the present invention, on the surface of the sheet-like activated carbonaceous structure, for example, a metal foil, a metal plate, a conductive powder and an organic binder made of the above-mentioned material for forming a current collector are provided. A conductor layer serving as a current collector is formed by applying a conductor paste containing

At this time, the sheet-like activated carbonaceous structure and the current collector are integrated by thermocompression bonding at 60 to 100 ° C. and 20 to 50 MPa, or a contact liquid or an adhesive is interposed between the sheets. By applying and bonding, this can prevent delamination during heat treatment and enhance the sinterability between the sheet-like activated carbonaceous structure and the current collector. It is desirable not to use an adhesive or the like.

Further, the sheet-like activated carbonaceous structure forming two electrodes for the same electrode (for example, a positive electrode and a positive electrode) is laminated on both main surfaces of the conductor layer forming the current collector, and The shape retention of the molded body is improved by making the periphery of the layer smaller than the periphery of the sheet-like activated carbonaceous structure and bonding the outer periphery of the two sheets of the activated carbonaceous structure to each other. In addition, there is an operational effect that delamination during heat treatment can be prevented and sinterability between the sheet-like activated carbonaceous structure and the current collector can be enhanced.

Next, if desired, a laminate of the sheet-shaped activated carbonaceous structure and the conductor layer is placed in an oxidizing atmosphere for 1 hour.
After performing aging treatment by heating to 50 to 300 ° C. and holding, a carbonizing treatment is performed in a non-oxidizing atmosphere to carbonize the organic binder component, and the current collector and the activated carbon are sintered and integrated.

The heating temperature is set at 500 to 500 to maintain the strength of the activated carbonaceous structure, increase the specific surface area of the activated carbon in the electrode, and prevent the current collector from melting.
Desirably, the temperature is 1100 ° C.

Here, according to the present invention, the heat treatment temperature of the laminate of the sheet-shaped activated carbonaceous structure forming the positive electrode and the conductor layer is set to the sheet-shaped activated carbonaceous structure forming the negative electrode and the conductor. It is desirable to lower the heat treatment temperature of the laminate with the layer, whereby the oxygen content of the activated carbon in the electrode forming the positive electrode can be larger than the oxygen content of the activated carbon in the electrode forming the negative electrode, Capacitance can be increased, carbon dioxide gas, oxygen gas or other impurities due to functional groups on the surface of the activated carbon particles in the negative electrode can be prevented, and the internal resistance of the negative electrode can be reduced. Shape can be improved.

The specific heating temperature is 500 to 1000 ° C., preferably 600 to 900 ° C., for the heat treatment of the laminate of the sheet-shaped activated carbonaceous structure forming the positive electrode and the conductor layer.
C., and the heat treatment temperature of the laminate of the sheet-shaped activated carbonaceous structure forming the negative electrode and the conductor layer is 7 ° C.
The temperature is desirably from 00 to 1100 ° C, especially from 850 to 1000 ° C in order to reduce the oxygen content in the negative electrode.

When a metal is used for the conductor layer, the melting point of the negative electrode side metal may be higher than that of the positive electrode side metal in terms of the heat treatment temperature.

Then, an integral body of the positive electrode and the current collector and an integral body of the negative electrode and the current collector are disposed so that the respective electrodes face each other, and the above-described arrangement is provided between the electrodes. The separator is laminated so as to contact and interpose, and the laminated body is inserted into a bag-like sealing material with the terminal portion of the current collector protruding, for example, and the above-described electrolytic solution is inserted through the opening of the sealing material. After injecting a liquid to impregnate the electrode and the separator, the opening of the sealing material is hermetically sealed, whereby an electric double layer capacitor can be manufactured.

If the steps from the heat treatment to the assembling are performed in a dry atmosphere using a glow box or the like, an efficient drying can be achieved without the need for an extra drying step or the like.
The amount of water in the electric double layer capacitor can be reduced.

[0044]

EXAMPLES (Example) 100 parts by weight of activated carbon powder having a specific surface area of 1000 m ² / g obtained by carbonizing and activating a coconut shell.
Each 50 parts by weight of polyvinyl butyral (PVB) was mixed and stirred with a high-speed mixing stirrer.
After performing a mesh pass with 0 mesh, roll forming was performed to form a sheet-shaped molded body, which was cut into a rectangular shape.

Also, as shown in FIG. 1, each of a positive electrode and a negative electrode current collector having a rectangular shape with one side of 15 mm square and one end having a terminal part having a width of 5 mm and a length of 15 mm is formed of a metal foil shown in Table 1. did. Then, the two sheet-like activated carbonaceous structures are laminated on both surfaces of the current collector as shown in FIG.
Thermocompression bonding was performed at 40 ° C. and 40 ° C. to be integrated.

The laminate of the sheet-like activated carbonaceous structure and the metal foil was subjected to an aging treatment at 200 ° C. in the air, and then to a heat treatment at a temperature shown in Table 1 in vacuum to obtain a positive electrode and a negative electrode. The above-mentioned sheet-like activated carbonaceous structure having a length of 30 mm, a width of 30 mm and a thickness of 1.0 mm and a current collector having a rectangular shape having a side of 15 mm and a terminal portion having a width of 5 mm and a length of 15 mm at one end. This was made integrally. In addition, it was confirmed that the interface between the current collector and the activated carbonaceous structure was sintered by SEM observation.

The obtained laminate of the activated carbonaceous structure constituting the positive electrode and the negative electrode and the current collector are disposed so that the activated carbonaceous structure side faces each other, and two activated carbonaceous structures for the positive electrode and the negative electrode are provided. They were laminated with a cellulose separator interposed between the bodies. Further, the laminate was inserted into a bag made of an aluminum laminate provided with an electrolyte injection port in advance, and the portion of the aluminum laminate bag other than the electrolyte injection port was sealed, and then the electrolyte injection was performed. 1 mol / l of tetraethylammonium tetrafluoroborate (E
A propylene carbonate (PC) solution of t ₄ NBF ₄ ) was vacuum-injected as an electrolytic solution, and the injection port was sealed with a heat block sealer to produce an electric double layer capacitor rated at 3 V and 20 F. The above-described steps from baking to sealing were performed in a glow box.

Here, regarding the electric double layer capacitor,
The charge and discharge currents were constant at 20 mA, and the capacitance was measured from the sum of the voltages during the entire discharge time and the current value. Also,
The impedance was measured at 1 KHz and 20 mA, and this was defined as the internal resistance. Further, a DC voltage of 3.0 V
The capacitance when applied for 2000 hours at a temperature of ° C. was measured, and the rate of decrease from the initial value was evaluated as the rate of change in capacitance. The results are shown in Table 1.

Further, the activated carbonaceous structure was pulverized to prepare an aqueous solution to which each of the reagents shown in Table 2 was added, and this solution was titrated with hydrochloric acid to calculate the amount of each surface functional group on the activated carbon surface.
Based on this, the oxygen content in the activated carbon was estimated. The results are shown in Table 1.

[0050]

[Table 1]

[0051]

[Table 2]

As is clear from Table 1, each sample has excellent characteristics with an electrostatic capacity of 21.0 F or more and an internal resistance of 4.0 Ω or less. Sample No. having a firing temperature of 880 ° C. or higher. Nos. 1 to 15 had excellent characteristics with a capacitance change rate of -9% or less.

(Comparative Example) The sheet-like activated carbonaceous structure of the example was used alone, subjected to aging treatment at 200 ° C. in air, and then to carbonization heat treatment at 900 ° C. in vacuum. An electric double layer capacitor was formed in the same manner as in the example except that the activated carbon structure and the current collector were laminated by laminating an Al current collector having the same shape as that of the example on one surface of the activated carbonaceous structure. As a result of fabrication and evaluation, the capacitance was 2
The resistance was as low as 0.5 F and the internal resistance was as high as 5.2 Ω.

[0054]

As described above in detail, according to the electric double layer capacitor of the present invention, the polarizable electrode of the electric double layer capacitor and the current collector are integrally formed by sintering, so that the internal The resistance is small and the capacitance can be large.

[Brief description of the drawings]

FIG. 1A is a schematic sectional view showing an example of an electric double layer capacitor of the present invention, and FIG. 1B is a partial plan view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric double layer capacitor 2 Electrode 3 Separator 4 Current collector 5 Sealing material 6 Laminate

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinya Matsuno 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute (72) Inventor Naomo Sojo 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Kyocera Research Institute

Claims (7)

[Claims] 1. A pair of current collectors forming a positive electrode and a negative electrode, a polarizable electrode forming an active carbon-containing positive electrode and a negative electrode laminated on the respective current collector surfaces, and a polarizable material forming the positive electrode and the negative electrode A separator interposed between the electrodes, wherein the polarizable electrode forming the positive electrode and the negative electrode and the current collector are integrally formed by sintering, respectively. Electric double layer capacitor. 2. The current collector on the positive electrode side is made of Al, Ti, Ta,
At least one selected from the group consisting of Ag, Nb, Pt, and Au
And the current collector on the negative electrode side is C
The electric double layer capacitor according to claim 1, wherein the capacitor is made of at least one metal selected from the group consisting of u, Ag, Ni, Pt, and Au. 3. The electric power according to claim 1, wherein the oxygen content of the activated carbon in the polarizable electrode on the positive electrode side is larger than the oxygen content of the activated carbon in the polarizable electrode on the negative electrode side. Double layer capacitor. 4. A process for producing a sheet-like activated carbonaceous molded article for a positive electrode and a negative electrode containing activated carbon powder, and a conductor for a positive electrode or a negative electrode current collector on one surface of each activated carbonaceous molded article. A step of laminating the layers, and a step of heat-treating each of the molded bodies obtained by laminating the conductor layer at a temperature equal to or lower than the melting point of the conductor layer, and sintering to integrally form the activated carbonaceous structure and the current collector The integrated body of the activated carbonaceous structure and the current collector for the positive electrode and the negative electrode is disposed so that the activated carbonaceous structure side faces each other, and laminated with a separator interposed between the activated carbonaceous structure surfaces. And a step of filling the activated carbonaceous structure and the separator with an electrolytic solution to form a positive electrode and a negative electrode polarizable electrode and a separator. . 5. The heat treatment temperature of the activated carbonaceous structure on the positive electrode side and the current collector is lower than the heat treatment temperature of the activated carbonaceous structure on the negative electrode side and the current collector. Item 5. The method for producing an electric double layer capacitor according to Item 4. 6. The current collector on the positive electrode side is made of Al, Ti, Ta,
At least one selected from the group consisting of Ag, Nb, Pt, and Au
And the current collector on the negative electrode side is C
6. The method for manufacturing an electric double layer capacitor according to claim 5, comprising at least one metal selected from the group consisting of u, Ag, Ni, Pt, and Au. 7. The polarizer according to claim 4, wherein the oxygen content of the activated carbon in the polarizable electrode on the positive electrode side is larger than the oxygen content of the activated carbon in the polarizable electrode on the negative electrode side. A method for producing the electric double layer capacitor according to the above.