JPS60167412A - Method of producing 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 The present invention relates to an electric double layer capacitor that utilizes an electric double layer formed at the interface between a polarizable electrode and an electrolyte.

Conventional Structures and Problems In electric double layer capacitors that use activated carbon powder or activated carbon fibers as polarizable electrodes, a punched metal such as aluminum or titanium is used as the current collector 1, as shown in Figure 1. A polarizable electrode 2 containing activated carbon powder as a main component was supported on the surface of the electric body 1 by either mold-pressing or rolling.

In the figure, 3 is a separator.

In such a current collector, the current collector metal and the activated carbon powder are in mere physical contact via a binder, and the contact resistance is large and mechanical strength cannot be expected.

On the other hand, as the polarizable electrode 2, a cloth 2 paper or felt-like material whose main component is activated carbon fiber as shown in FIG.
There are some in which a metal layer such as titanium is formed by a thermal spraying method or a vapor deposition method. In Figure 2, 3 is the separator, 4 is the case, and 6
is a gasket. For example, when aluminum metal, etc. is thermally sprayed or vapor-deposited on one side of a cloth-like activated carbon fiber, the adhesive strength between the activated carbon fiber, which is a polarizable electrode, and the metal current collector is stronger than in the case described in 31 above, and the contact between the two is strong. It has the advantage of reducing resistance. However, in the thermal spraying method, the thermal spraying equipment is complicated and is still an expensive equipment. However, the vapor deposition method has a major drawback in that it cannot be produced unless it is a batch method, and is not suitable for mass production.

1. There is a polarizable electrode that is used as a current collector by forming a conductive paint layer containing metal particles or carbon particles as conductive particles using a dipping method, a coating method, a screen printing method, or the like.

Such a method makes it possible to form a current collector very easily and without requiring any special equipment.

However, as is generally known, conductive paints have a higher specific resistance than metals, which not only makes it impossible to charge them quickly, but also increases the IR drop caused by discharge overvoltage when a strong discharge is performed. It has the following drawbacks. In fact, if organic substances are used as the binder to bind the conductive particles, deterioration is likely to occur over long periods of use.

JP-A No. 1997-112000-IG7412 (2) Object of the Invention The present invention aims to improve the current collecting ability of the current collector of such an electric double layer capacitor.

Structure of the Invention In order to achieve this object, the present invention is characterized in that a conductive electrode (current collector) is formed on the surface of a polarizable electrode by a chemical plating method.

Explanation of Examples In electroplating, metal ions are reduced by an external electric current and deposited as metal on the cathode, whereas a chemical method is used to reduce metal ions in a solution without using an external electric current. Among these plating methods, catalytic chemical plating is particularly suitable for the present invention. Furthermore, when electroplating a polarizable electrode, the lower the electrical conductivity of the polarizable electrode, the more difficult the electroplating becomes. Plating is also possible.

Next, I will explain one process of chemical plating. Ru.

[1.Surface conditioning] A final process that involves degreasing, etching, etc. to remove dirt from the surface of the material and improve the adhesion of the plating film.

[2 Catalyticization] Au is added to the surface of the material to start the chemical plating reaction.
, a step of providing noble metal catalyst nuclei such as Pt, Pd, and Ag.

[3] Chemical plating reaction When a catalyzed conductor or non-conductor is immersed in a chemical plating solution containing a chemical reducing agent, a chemical plating reaction begins immediately. The deposited metal directly becomes a catalyst for the plating reaction, and the plating reaction continues.

(Example 1) The first activated carbon fiber with a specific surface area of 2000 m1/g
Chemical plating of nickel was performed using the composition baths shown in Tables 5 to 5 to form current collectors. Using chemical plating, it is possible to form an extremely uniform plating layer on the polarizable electrode. The plating baths in Table 1.2 used hydrazine as the reducing agent, and the plating baths in Table 3.4.6 used hypophosphite.

A current collector was thus formed, and a coin-shaped capacitor as shown in FIG. 3 was manufactured. The electrode area is approximately 160m
It was A. As the separator 3, one made of polypropylene was used. There are 6 plating layers. 9 is an activated carbon fiber which is a polarizable electrode.

Table 6 shows the characteristics of capacitors whose current collectors were formed by chemical plating under the conditions shown in Tables 1 to 6. The same table also shows the electrolyte used.

Table 1 End of Table 2...; JP-A-167412(3) 9. From Table 6, it can be seen that all capacitors exhibit good characteristics (especially impedance).

Furthermore, by using the Nylikel chemical baths listed in Tables 1 and 2, capacitors exhibiting even better characteristics can be obtained. This is due to the N1-P containing 6-16% phosphorus in the 7kg from the hypophosphite bath described in Table 3.4.5.
This is thought to be due to the fact that, in contrast to alloys, those using the hydrazine bath shown in Table 1.2 generally have a slower plating rate, but the resulting plating film is close to pure 2.J Kel.

(Example 2) Example 1. A current collector was formed by nickel chemical plating method under the conditions shown in Table 1,
A capacitor as shown in FIG. 4 was manufactured.

In the figure, 7 is activated carbon porous material, (1ooxcsox7mJ)
, 6 is a plating layer made of nickel, and 3 is a separator. 25 wt % potassium hydroxide was used as the electrolyte. 8 is a nickel lead wire. The characteristics of this capacitor are shown in Table 7, where 8' is a case.1. From Table 7, it can be seen that this capacitor has a large capacity and low impedance.

Table 7 (Example 3) A polarizable electrode made of activated carbon fibers with a specific surface area of 2000 m'/. A current collector is formed by the nickel chemical plating method described in Table 1. Metal lithium, which is a non-polarizable electrode, was used as the negative electrode, and a coin-shaped capacitor shown in FIG. 3 was fabricated. In the figure,
9 is activated carbon fiber (diameter 14ii), 6 is a nickel plating layer, 3 is a separator, 10 is lithium, 5 is a gasket, and 4 is a case. Propylene carbonate containing 1 mol of lithium perchlorate was used as the electrolyte. The characteristics of this capacitor are shown in Table 8. From Table 8, it can be seen that the capacitor is small in size, has a large capacity, and can be used at a high voltage.

11.

Table 8 (Example 4) The same activated carbon fiber as in Example 1 was used as a polarizable electrode, and the surface was chemically plated with cobalt using the plating bath shown in Table 9 and the plating bath shown in Table 10. Cobalt-nickel alloy chemical plating was performed to form a current collector.

Table 9 Table 10 JP-A-167412 (4) Then, the coin-shaped capacitor shown in FIG. 3 was fabricated using this electrode at a month it of -1.

Table 11 shows the capacitor characteristics.

The electrolyte contains 1 mol of tetraethyl ammo perchlorate ÷
Propylene carbonate containing aluminum was used.

Table 11 From Table 11, it can be seen that even if chemical plating of cobalt is used, a capacitor as good as that of nickel can be obtained.

Effects of the Invention As described above, in the present invention, since a conductive electrode as a current collector is formed using a chemical plating method, it is possible to firmly form a uniform current collector on a polarizable electrode. Therefore, it is possible to obtain an electric double layer capacitor having a small-sized dog's tolerance and extremely excellent current collecting ability.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the main parts of a conventional electric double layer capacitor, Fig. 2 is a half-sectional front view showing the configuration of a flat coin type conventional electric double layer capacitor, and Figs. 3 to 5 are respectively FIG. 1 is a cross-sectional view showing an electric double layer capacitor according to an embodiment of the present invention. 1... Current collector, 2... Polarizable electrode, 6-
... Plated layer, 7 ... Activated carbon porous body, 9-...
・Activated carbon fiber. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Reason@2 diagram

Claims (3)

[Claims] (1) A method for manufacturing an electric double layer capacitor, which comprises forming a conductive electrode on the surface of a polarizable electrode by chemical plating. (2) The method for manufacturing a drowsy double layer capacitor according to claim 1, wherein the metal to be chemically plated as the conductive electrode is dichloromethane, cobalt, cobalt, or an alloy thereof. (3) The electric electrode according to claim 1, wherein the polarizable electrode is activated carbon in the form of paper, felt, non-woven fabric, or porous material. A method for manufacturing a multilayer capacitor.