JP2000348987A - Method for manufacturing electrode of electric double layer capacitor - Google Patents

Abstract

(57) Abstract: Provided is a method for manufacturing an electrode of an electric double-layer capacitor in which a two-layer electrode material composed of a metal foil layer and an activated carbon layer is formed by reducing the contact resistance between the two. A flexible aluminum foil (1) is placed on a press lower plate (5) having a plurality of projections (4), and an activated carbon cloth (2) is placed on the aluminum foil (1). Press from above. At this time, the aluminum foil 1 is deformed along the projections 4 of the press lower plate 5 to form the projections 7, and the projections 7 are pressed into the activated carbon cloth 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a two-layer electrode material comprising a metal foil layer and an activated carbon layer, which is used as an electrode of an electric double layer capacitor.

[0002]

2. Description of the Related Art As shown in FIG. 3, an electric double-layer capacitor has positive and negative electrodes 3 through a separator 30 made of polyethylene, polypropylene or the like impregnated with an electrolyte solution.
1 and 31 are arranged facing each other. And electrode 3
1, 31 are electrode plates 32, 32 mainly composed of activated carbon having a large specific surface area to increase the capacitance, and electric charges stored in the electrode plates 32, 32 in contact with the electrode plates 32, 32. Of a metal foil layer (current collecting metal foil 33) and an activated carbon layer (electrode plate 32) formed by superposing current collecting metal foils 33, 33 for discharging the electric current and charging the electrode plates 32, 32 with each other. A layer electrode material is used.

In such a configuration, the electrolyte solution impregnated in the separator 30 penetrates into the electrode plate 32, and positive and negative charges are opposed to each other at a very short distance from the interface where the electrode plate 32 and the electrolyte solution are in contact. To form an electric double layer,
The electric double layer functions as a capacitor.

The lower the contact resistance between the electrode plate 32 and the current collecting metal foil 33, the better the charge / discharge performance of the electric double layer capacitor. Therefore, various manufacturing methods are used to reduce the contact resistance between the two. ing. For example, a uniform activated carbon cloth made of fibrous activated carbon is used for the electrode plate 32, and a flexible metal foil such as an aluminum foil is used for the current collecting metal foil 33. 2. Description of the Related Art Forming a two-layer electrode material having a thickness has been performed. When the activated carbon cloth and the flexible metal foil are overlapped and pressed as described above, the activated carbon cloth has a certain degree of elasticity, so that the adhesion between the activated carbon cloth and the metal foil increases, and the contact resistance between the two decreases. be able to.

[0005] A method of forming a two-layer electrode material having a metal foil layer having a uniform thickness and an activated carbon layer by coating a metal foil with a coating agent containing activated carbon and rolling the coating material is also known. Are known. In this manufacturing method, the coated surface of the metal foil is subjected to a bare line treatment or an etching treatment in advance and then applied, whereby the adhesiveness between the metal foil and the coating agent is increased, and the contact resistance between the two is reduced.

However, the electric double layer capacitor is required to further improve the charge / discharge performance, and further reduces the contact resistance between the two electrodes of the metal foil layer and the activated carbon layer. The need is growing.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has been made in view of the above circumstances, and provides an electric double layer in which a two-layer electrode material comprising a metal foil layer and an activated carbon layer is formed by reducing the contact resistance between the two. An object of the present invention is to provide a method for manufacturing a capacitor electrode.

[0008]

In order to achieve the above object, a first embodiment of the present invention is to press a flexible metal foil and an activated carbon cloth made of a fibrous activated carbon into a cloth. Then, in the method for manufacturing an electrode of an electric double layer capacitor forming a two-layer electrode material having a predetermined thickness having a metal foil layer and an activated carbon layer, a plurality of protrusions are provided after the metal foil and the activated carbon cloth are overlapped. A press plate is brought into contact with the metal foil side and pressed, and the projection is pressed into the inside of the activated carbon cloth via the metal foil.

According to the present invention, since the metal foil has flexibility and the activated carbon cloth has some elasticity, the metal foil and the activated carbon cloth are overlapped and the press plate is placed on the metal foil side. When pressed against the metal foil, the metal foil is deformed by the projections of the press plate and pressed into the activated carbon cloth, and the activated carbon cloth is elastically urged around the pressed metal foil to be in close contact with the metal foil. Become.
Therefore, the contact area between the metal foil and the activated carbon cloth is increased as compared with the case where the metal foil and the activated carbon cloth are pressed by a flat press plate, and the contact resistance between the two can be reduced. Further, by pressing the deformed portion of the metal foil into the activated carbon cloth, it is possible to prevent the metal foil from being displaced when the metal foil is thermally expanded.

In a second embodiment of the present invention, a flexible metal foil is coated with a coating agent containing activated carbon and rolled to a predetermined thickness having a metal foil layer and an activated carbon layer. In the method for manufacturing an electrode of an electric double layer capacitor for forming a two-layer electrode material, after applying the paint on one surface of the metal foil,
The metal foil is rolled while a roll provided with a plurality of protrusions is in contact with the other surface of the metal foil, and the protrusions are pressed into the paint via the metal foil.

According to the present invention, after the metal foil is coated with the coating agent, when the roll is brought into contact with the metal foil and rolled, the metal foil is deformed by the protrusions of the roll. The coating agent is pressed into the inside of the coating agent, and the coating agent comes into close contact with the periphery of the pressed metal foil. Therefore, the contact area between the metal foil and the coating agent is increased and the contact resistance between the two can be reduced as compared with the case where the coating agent is applied to the metal foil and then rolled with a flat roll.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First and second embodiments of the present invention will be described with reference to FIGS. 1 and 2 are process diagrams of a method of manufacturing a two-layer electrode material used as an electrode of an electric double layer capacitor, and FIG. 3 is a structural diagram of the electric double layer capacitor.

Referring to FIG. 3, the electric double-layer capacitor is constituted by a pair of two-layer electrodes (positive electrode, negative electrode) 31 facing each other via a separator 30 impregnated with an electrolyte solution.

The separator 30 is made of a filterable material formed of a resin such as polyethylene or polypropylene having a resistance to an electrolyte solution. Further, as the electrolyte solution impregnated in the separator, for example,
For solvents such as acetonitrile and propylene carbonate,
4-ethylammonium boron tetrafluoride (TEATF
What melt | dissolved B) is used.

The two-layer electrode 31 includes an activated carbon layer 32 and a metal foil layer 33. The electrolyte solution impregnated in the separator 30 penetrates into the activated carbon layer 32, and an electric double layer functioning as a capacitor is formed at the interface where the activated carbon layer 32 and the electrolyte solution come into contact. Since the metal foil layer 33 is a current collector that charges the electric double layer with electric charge and discharges electric charge from the electric double layer, the lower the contact resistance between the activated carbon layer 32 and the metal foil layer 33, the lower the resistance. In addition, the charge and discharge performance of the electric double layer capacitor is improved.

The first and second embodiments of the present invention for producing a two-layer electrode material 31 used as an electrode of an electric double layer capacitor by reducing the contact resistance between the activated carbon layer 32 and the metal foil layer 33 will be described below. The embodiment will be described.

First, a first embodiment of the present invention will be described with reference to FIGS. 1 (a) to 1 (c). In this embodiment, an aluminum foil 1 (corresponding to the flexible metal foil of the present invention) having a thickness of about 0.1 mm and an activated carbon cloth 2 made of fibrous activated carbon in a cloth form form a metal foil layer ( A two-layer electrode material 3 comprising an aluminum foil 1) and an activated carbon layer (activated carbon cloth 2) is formed.

First, referring to FIG. 1A, the aluminum foil 1 is placed on a press lower plate 5 provided with a plurality of protrusions 4 facing upward. An activated carbon cloth 2 is placed on the aluminum foil 1. Then, it is pressed from above by the press upper plate 6.

Thus, referring to FIG. 1B, the aluminum foil 1 and the activated carbon cloth 2 are pressed against each other.
The portion of the aluminum foil 1 in contact with the conical protrusion 4 provided on the press lower plate 5 is deformed along the shape of the protrusion 4 to form a conical convex portion 7, and the convex portion 7 is activated carbon. Cross 2
Pressed into the inside. Then, referring to FIG.
In the two-layer electrode material 3 formed of the metal foil layer (aluminum foil 1) and the activated carbon layer (activated carbon cloth 2) formed in this manner, the state where the activated carbon cloth 2 adheres around the convex portion 7 of the aluminum foil 1 Become.

For this reason, as shown in FIG. 1D, the two-layer electrode material 13 composed of the aluminum foil 11 and the activated carbon cloth 12 formed by pressing using a conventional flat press lower plate is more effective than the aluminum foil and the activated carbon cloth. The contact area increases, and the contact resistance between the two can be reduced. Then, FIG. 1 (a),
As shown in (b), the formation of the convex portion 7 of the aluminum foil 1 and the press-fitting of the convex portion 7 into the activated carbon cloth 2 are performed by a conventional method in which the aluminum foil 1 and the activated carbon cloth 2 are formed to a predetermined thickness. It is performed simultaneously in the pressing step of pressing. Therefore, the number of manufacturing steps of the two-layer electrode material 3 does not increase. Furthermore, by pressing the convex portion 7 of the aluminum foil 1 into the inside of the activated carbon cloth 2, when thermal expansion or the like of the aluminum foil 1 occurs, the two can be hardly displaced.

When the aluminum foil 1 and the activated carbon cloth 2 are overlapped with each other, they may be adhered to each other using a binder to further enhance the adhesion between the two.

In this embodiment, as shown in FIG. 1A, an aluminum foil 1 is provided on a press lower plate 5 provided with a projection 4.
Was placed on the aluminum foil 1 and the activated carbon cloth 2 was placed on the aluminum foil 1 and pressed by a flat plate upper plate. Conversely, the activated carbon cloth 2 was placed on a flat plate lower plate and the activated carbon cloth 2 was placed on the lower plate. Alternatively, the aluminum foil 1 may be overlaid on the top and pressed by a press upper plate provided with projections.

Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, a coating agent 21 containing activated carbon is applied to an aluminum foil 20 (corresponding to the flexible metal foil of the present invention) having a thickness of about 0.1 mm to form a metal foil layer (aluminum). Foil 20) and activated carbon layer (coating liquid 2)
The two-layer electrode 22 of 1) is formed. The coating agent 21 contains, in addition to the activated carbon, a conductive agent for conducting between the activated carbons and a binder for fixing the activated carbon and the conductive material during drying.

FIG. 2 is a cross-sectional view showing a step of applying a coating agent 21 to the aluminum foil 20.
Is transported to a rolling section 24 by a feed roller 23. The coating agent 21 is filled in a tank 25, and is applied to the surface of the aluminum foil 20 by the upper roll 26. And
The aluminum foil 20 coated with the coating agent 21 is a roll-up roll 26 and a roll-down roll 27 (corresponding to the roll of the present invention).
Is rolled to a uniform thickness.

The lower roll 27 has a plurality of conical projections 28. For this reason, when the aluminum foil 20 is rolled, the portion of the aluminum foil 20 that contacts the projection 28 is deformed along the shape of the projection 28 to form a conical projection 29, and the projection 29 is 20 is press-fitted into the inside of the coating material 21 applied.

When the coating agent 21 is dried and cured, the metal foil layer (aluminum foil 20) and the activated carbon layer (coating agent 2)
1) is formed. in this way,
By pressing the projection 29 of the aluminum foil 20 into the coating material 21, the coating agent 21 covers the periphery of the projection 29.
Thus, similarly to the first embodiment described above, the aluminum foil 22 and the coating agent 21 can be formed more than when rolling is performed by using a flat (not provided with the projections 28) lower roll 27 as in the related art. And the contact area between them can be increased, and the contact resistance between them can be reduced.

The formation of the convex portion 29 of the aluminum foil 20 and the press-fitting of the convex portion 29 into the coating agent 21 are performed by coating the aluminum foil 20 with the coating agent 21 by a predetermined thickness. This is performed simultaneously in the step of rolling. Therefore, the number of manufacturing steps for the two-layer electrode material 22 does not increase. Further, similarly to the above-described first embodiment, the protrusions 2 of the aluminum foil 20 are formed.
By press-fitting 9 into the coating agent 21, when the aluminum foil 1 undergoes thermal expansion or the like, it is possible to prevent the two from slipping.

In the first and second embodiments, the projections 4 provided on the lower press plate 5 and the projections 28 provided on the lower roll 27 are formed in a conical shape, so that the aluminum foil has a conical shape. Are formed, but the shapes of the projections 4 and 28 are not limited to this, and may be any shape such as a triangular pyramid or a hemisphere that can be easily pressed into the activated carbon cloth 2 or the coating material 21. Good.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of a two-layer electrode material according to a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of a two-layer electrode material according to a second embodiment of the present invention.

FIG. 3 is a structural diagram of an electric double layer capacitor.

[Explanation of symbols]

1 ... aluminum foil, 2 ... activated carbon cloth, 3 ... two-layer electrode material, 5
… Press lower plate, 6… Press upper plate, 20… Aluminum foil, 21
... Coating agent, 22 ... Two-layer electrode material, 26 ... Roll-up roll, 2
7 Roll under roll

Claims (2)

[Claims] 1. A two-layer electrode material having a predetermined thickness having a metal foil layer and an activated carbon layer is formed by superposing and pressing a flexible metal foil and a cloth-shaped activated carbon cloth made of fibrous activated carbon. In the method for manufacturing an electrode of an electric double layer capacitor, after stacking the metal foil and the activated carbon cloth, a press plate provided with a plurality of projections is pressed against the metal foil side and pressed, and the projections are interposed through the metal foil. And press-fitting the inside of the activated carbon cloth. 2. An electric double layer in which a coating agent containing activated carbon is applied to a flexible metal foil and rolled to form a two-layer electrode material having a predetermined thickness having a metal foil layer and an activated carbon layer. In the method of manufacturing an electrode of a capacitor, after applying the coating agent on one surface of the metal foil, rolling the metal foil while abutting a roll provided with a plurality of protrusions on the other surface of the metal foil. And press-fitting the projection into the coating agent through the metal foil.