JPS61203615A - Electric doule-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 an electric double layer capacitor using activated carbon as a polarizable electrode.

Conventional technology Conventionally, the electrode bodies of electric double layer capacitors using this type of electrolyte have been made by press-molding activated carbon particles or kneading them with a suitable binder and coating them on a metal current collector. Ta. In addition, when activated carbon fibers are used, a method is known in which a sprayed aluminum layer is formed on the activated carbon fibers, and the electrode body is made by spot welding the electrode case made of strong stainless steel as the case material and the sprayed aluminum layer. Ta. In addition, electrical connection with the outside is performed through mechanical contact such as lead terminals.

Problems to be Solved by the Invention In an electric double layer capacitor made of such a current collector case material, in normal use, electricity is supplied through mechanical contact with the outer surface of the current collector case, such as a lead or a terminal.

However, if the above products are left for a long time or used, a passive state such as a oxidized film will form on the surface of the metal case due to oxygen and moisture in the air, and the contact resistance will gradually increase. When electric double layer capacitors are used, there is a problem in that the voltage drop becomes large and the capacitors cannot be put to practical use.

The present invention solves these drawbacks and makes it possible to obtain stable characteristics over a long period of time.

Means for solving the problems and the technical means of the present invention for solving the first problem mentioned above is that when the above-mentioned electric double layer capacitor is used, the outer surface of each or one of the metal cases is made passivated. Nickel is a difficult material to make.

It is coated with an alloy whose main components are lead, tin, zinc, chromium, gold, silver, copper, or any of the above metals.

action The effect of this technical means is as follows.

In other words, when stainless steel is left unused, oxygen and moisture in the air form a passivation film on its surface, such as an oxide film, but when these metals are used, either no passivation is created, or even if a passivation is formed, the film is not formed. Since it is thin, it can be used without any problem.

Therefore, it is desirable to combine a strong case material such as stainless steel with the above-mentioned metal.

Example The present invention will be explained below using specific examples.

[Example 1] As shown in Figure 1, a cloth made of phenolic activated carbon fiber (
Thickness 0.51111. A polarizable electrode 1 having a specific surface area of 2 ooom/g) with a conductive electrode formed thereon is cut out into a disk shape with a diameter of 2 using a punching die to obtain an electrode body. After this electrode body was impregnated with an electrolytic solution prepared by adding 10 Wt-% of tetraethylammonium (tetrafluoropole) to propylene carbonate.

These are stacked with a separator 2 interposed between them, and then sandwiched between a stainless steel case 3 whose outer surface is coated on one or both sides with a metal shown in Table 1.
A gasket 4 is placed at the open end of the opening, and the opening is sealed by caulking. 5 is a metal film.

Table 1 shows the characteristics of the electric double layer capacitor according to the present invention. Similarly, Table 1 shows, for comparison, the characteristics of a prototype case having a structure in which the outer surface of the stainless steel case was not coated with the above-mentioned metal.

(Left below) [Example 2] As shown in Figure 2, a cloth made of acrylic activated carbon fiber (thickness 0
．． A polarizable electrode 1 having a conductive electrode formed on one side and having a diameter of 2α is punched out with a punching die to obtain an anode electrode body.

A non-polarizable electrode 6 having a diameter of 2 m, for example lithium, is stacked on this electrode body as a cathode electrode body, with a separator 2 interposed between each electrode body to form a set of electrode bodies. This-
After the electrode body of the set is impregnated with an electrolytic solution containing propylene carbonate and 10 wt% lithium fluoroborate, this is sandwiched between a stainless steel case 3 whose outer surface is coated on one or both sides with the metal. A gasket 4 is placed at the open end of the opening, and the opening is sealed by caulking.

Table 2 shows the characteristics of the electric double layer capacitor according to the present invention. Similarly, Table 2 shows, for comparison, the characteristics of a prototype of a structure in which the outer surface of the stainless steel case was not coated with the metal.

(Left below) As described above, this invention makes it easy to manufacture electric double layer capacitors that always have stable electrical contact resistance by taking advantage of the property that the metal coating is difficult to passivate due to oxygen, moisture, etc. in the air. This is what you can get.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the electric double layer capacitor of the present invention, and FIG. 2 is a sectional view showing another embodiment of the electric double layer capacitor of the present invention. DESCRIPTION OF SYMBOLS 1... Polarizable electrode, 2... Separator, 3... Case, 6... Metal film, 6
...Non-polarizable electrode.

Claims (3)

[Claims] (1) A conductive electrode is formed on one side of a polarizable electrode made of activated carbon fiber or activated carbon powder, and a counter electrode is arranged on the other side of the polarizable electrode via an electrolyte to form an element,
This element is housed in a pair of metal cases, and the conductive electrode on the polarizable electrode and the counter electrode are brought into electrical contact with each of the metal cases. An electric double layer capacitor characterized in that its outer surface is coated with nickel-lead, zinc, chromium, tin, silver, copper, gold, and an alloy containing the above metals as main components. (2) The electric double layer capacitor according to claim 1, wherein a polarizable electrode made of activated carbon fiber or activated carbon powder with a conductive electrode formed on one side is used as the counter electrode. (3) The electric double layer capacitor according to claim 1, wherein a non-polarizable electrode is used as the counter electrode.