JPH03188368A - Electric double-layer capacitor and manufacture thereof - Google Patents

Abstract

PURPOSE:To decrease internal resistance by bringing a current collector comprising a conductive material, wherein fine conductive particles are mixed into a base material, into contact with a specified surface of a porous electrode body comprising fine sintered carbon particles, attaching the current collector to the surface, and inserting a part of the current collector into the hole part of the porous electrode body a while contacting therewith. CONSTITUTION:As an electrode 1, a porous plate-shaped electrode body is formed by baking or sintering the particles of active carbon as a raw material. The electrode body is impregnated with a specified electrolyte. Since the raw materials are bonded together, the internal resistance exhibits a low value. Since the porous raw material is used, a large area is provided. As a current collector 2, conductive unvulcanized rubber is brought into contact with the electrode body. Heat curing is performed, and the rubber is brought into close contact with the electrode body. Therefore, the conductive rubber flows into the inner parts of the porous hole parts. The contact area between the electrode body and the current collector 2 becomes large. Thus the electric contact resistance becomes small. In this way, a capacitor characterized by the large capacitance and the lower internal resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a large capacitance electric double layer capacitor using the electric double layer principle and a method for manufacturing the same.

(Prior Art) In recent years, large-capacity capacitors using the electric double layer principle have been developed as backup power sources for memories in electronic devices, and are widely used by being incorporated into microcomputers, IC memories, and the like.

Conventionally, this type of electric double layer capacitor uses a paste-like electrode made of activated carbon and an electrolyte, and the contact resistance between the activated carbons is high, and the contact resistance between the activated carbon serving as the electrode and the current collector. There were disadvantages such as large size.

FIG. 6 is a cross-sectional view showing an example of a conventional electric double layer capacitor, in which 10 is an electrode, which is made by impregnating an aggregate of porous activated carbon powder with a predetermined electrolyte to form a paste;
30 is a gasket made of an insulator, and a separator 40 is provided to divide the inside of the gasket into upper and lower halves. The above-mentioned paste-like electric current g110.10 is placed in the space above and below the gasket 30 and the separator 40, and a conductive and elastic current collector 20.20 is adhered to the periphery of the gasket 30 to connect the electrode to , to are pressurized, and the contact between the electric current 8i10 and the current collector 20 is measured.

And in this way usually 1-100 Kg in the basic cell
A pressure of about /cm2 is applied to reduce the internal resistance of the electrode itself and the contact resistance between the electrode and the current collector.

(Problems to be Solved by the Invention) As mentioned above, in order to reduce the internal resistance of the electrode and the contact resistance between the electrode and the current collector, a method is proposed in which a predetermined pressure is applied to the basic cell and the pressure is maintained. However, in order to obtain a capacitor with a large capacitance, the electrode cross-sectional area of the basic cell must be increased. Therefore, it is necessary to increase the applied pressure, and there is a problem that it is difficult to increase the pressure due to the pressure application method and the exterior material.

The present invention was made in view of such problems,
It is an object of the present invention to provide a method for manufacturing an electric double layer capacitor that can inexpensively manufacture an electric double layer capacitor having a large electrode cross-sectional area.

Another object of the present invention is to provide an electric double layer capacitor with low internal resistance of the electrodes and low contact resistance between the electrodes and the current collector.

(Means for Solving the Problems) According to the present invention, a current collector made of a conductive material in which conductive fine particles are mixed into a base material is placed on a predetermined surface of a porous electrode body made of sintered carbon fine particles. An electric double layer capacitor is provided in which a part of the current collector is brought into contact with the pores of a porous electrode body by contact adhesion.

According to the present invention, one or more porous electrode bodies made of sintered carbon fine particles are heated and welded to a current collector made of a conductive material in which conductive fine particles are mixed into a base material. A method of manufacturing a characteristic electric double layer capacitor is provided.

(Function) According to the present invention, the resistance inside the electrode of an electric double layer capacitor having a large electrode cross-sectional area and the contact resistance between the electrode and the current collector can be reduced.

(Example) Next, an example of the present invention will be described in detail using the drawings.

FIG. 1 is a cross-sectional view showing one embodiment of an electric double layer capacitor according to the present invention, and FIG. 2 is a conceptual diagram in which part A in FIG. 1 is enlarged.

In these drawings, reference numeral 1 denotes an electrode, which is made by firing or sintering activated carbon fine particles to form a porous plate-shaped electrode body, and impregnating this electrode body with a predetermined electrolyte. Since the holes are bonded to each other, the internal resistance is low, and since the material is porous, it has an extremely large surface area. It is divided into upper and lower halves by a separator 4, and electrodes 1.1 are respectively disposed inside a gasket 3 made of an insulator.

2 is a current collector, which collects current by contacting one side of the electrode 1. Conductive fine particles are mixed with unvulcanized rubber as a base material, and made to contact and adhere to the electrode 1 by heat vulcanization. At the same time, the periphery of the current collector 2 is tightly adhered and fixed to the entire circumference of the gasket 3.

As shown in the enlarged conceptual diagram of FIG. 2, between the current collector 2 and the electrode 1, the current collector 2 is inserted into the hole of the fired or sintered activated carbon electrode 1. Their contact portions have an extremely large area and are configured to have an extremely low contact resistance between them.

Next, to explain the operation of this embodiment configured in this way, the electrode body is formed by firing or sintering using fine particles of activated carbon as a material, and since the particles of the material are bonded to each other, its internal resistance is A low value will be obtained.

In addition, conductive unvulcanized rubber was brought into contact with the electrode body as a current collector, and heat vulcanized to make it adhere to the porous electrode body, so that the conductive rubber could reach the inside of the porous pores. As the rubber flows in and the contact area between the electrode body and the current collector becomes large, the electrical contact resistance becomes small.

Therefore, by impregnating such an electrode body with a predetermined electrolyte, the charge accumulated on the large surface of the porous electrode body can be absorbed through the low internal resistance of the electrode body and the low contact resistance with the current collector. This means that a capacitor with large capacitance and low internal resistance can be obtained.

FIG. 3 is an enlarged conceptual diagram showing the connection between a porous electrode and a current collector in another embodiment of the present invention.

In the same figure, the electrode 11 is made by sintering fine particles of activated carbon to form a porous plate-shaped electrode body, which is impregnated with an electrolytic solution, in the same manner as in the previous embodiment.

The current collector 21 is formed by kneading fine carbon powder into an epoxy resin-based synthetic resin, applying this to the electrode body, solidifying it by heating or at room temperature, and adhering it to the entire periphery of the gasket. This is what I did. In this embodiment configured in this way, the material of the current collector 21, which is conductive by being mixed with carbon fine powder, enters the pores of the porous electrode body and solidifies upon contact. The contact area between the electrode 11 impregnated with the liquid and the current collector 21 becomes large, so that an extremely low value of contact resistance between them can be obtained.

Next, an example of a method for manufacturing an electric double layer capacitor will be described.

FIG. 4 shows a current collector 32 made of conductive rubber or a conductive synthetic resin material, and a plurality of polarizable electrode bodies 31 on the current collector 32.
The electrode structure is shown in which the electrodes are thermally fused together. The current collector 32 is
For example, Cu, Bs, AΩ.

It is coated on an electrode plate 33 made of a Zn carbon sheet, and the fired or sintered electrode body 31 placed thereon is directly heated, for example, by a hot press machine, and these current collectors 32° electrode body 31. The electrode plates 33 are fused together at the same time.

FIG. 5 shows a completed electric double layer capacitor in which a plurality of porous electrode bodies 31 are heated and welded in this manner and then separated into upper and lower halves by a separator 4 and sealed inside a gasket 3 made of an insulator. FIG. In this case, the separator 4 and the gasket 3 can be assembled using hot press or adhesive.

Note that the electrode plate 33 is not necessarily required, and the gasket 3 also serves as the current collector 32 at the same time as the plurality of porous electrode bodies 31.
It may be placed above.

Although the present invention has been described above with reference to the above embodiments, various modifications can be made within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

(Effects of the Invention) According to the electric double layer capacitor of the present invention, carbon fine particles made of activated carbon are fired or sintered to form a porous electrode body, so that the internal resistance of the electrode body is reduced, and
A current collector made of a conductive material with conductive particles mixed in the base material is brought into contact with the pores of the sintered porous electrode body, so the contact area between the electrode body and the current collector is large. As a result, the contact resistance is greatly reduced.

Further, according to the method for manufacturing an electric double layer capacitor of the present invention, its performance can be improved without applying external pressure to reduce the resistance value unlike conventional capacitors. Not only does it not require any pressure at all, but it also eliminates the need to use conductive adhesive, making it possible to reduce the contact resistance of large capacitance capacitors at low cost.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of an electric double layer capacitor according to the present invention, FIG. 2 is a conceptual diagram showing an enlarged portion A in FIG. 1, and FIG. 3 is a diagram showing another embodiment of the present invention. An enlarged conceptual diagram, FIG. 4 is an explanatory diagram showing a method for manufacturing an electric double layer capacitor having an electrode structure in which a plurality of electrode bodies are heat-sealed, and FIG. 5 is a cross-sectional view of the completed electric double layer capacitor. FIG. 6 is a sectional view showing an example of a conventional electric double layer capacitor. 1 11.31...electrode, 2,21.32...current collector, 3...gasket, 4...senor\lator.

Claims (4)

[Claims] (1) A current collector made of a conductive material in which conductive fine particles are mixed into a base material is brought into contact with a predetermined surface of a porous electrode body made of sintered carbon fine particles, and a part of the current collector is An electric double layer capacitor that penetrates into the pores of a porous electrode body. (2) The electric double layer capacitor according to claim 1, wherein unvulcanized rubber is used as the base material of the current collector, and the current collector is made to contact and adhere to the electrode body by thermal vulcanization. (3) A conductive thermosetting resin is used as the base material of the current collector, and the current collector is brought into contact with and adhered to the electrode body by heating or solidifying at room temperature.
) Electric double layer capacitors described in ). (4) A collector made of carbon fine particles sintered into a current collector made of a conductive substance with conductive fine particles mixed in the base material.
Alternatively, a method for manufacturing an electric double layer capacitor, which comprises heating and welding two or more porous electrode bodies.