JPS5933168Y2 - silver oxide battery - Google Patents

Description

[Detailed description of the invention] The present invention relates to a silver oxide battery that uses divalent silver oxide as the main positive electrode active material, and in particular a silver oxide battery that suppresses self-discharge in a thin battery structure and has excellent discharge performance. The purpose is to provide

In recent years, with the development and spread of small electronic devices such as electronic wristwatches and calculators, there has been a demand for small and large-capacity batteries.

Furthermore, as the amount of electricity consumed by electronic devices has become extremely low, the total height of batteries has come to around 2rrfIL.

When manufacturing a battery with a total height of about 2 rran, a battery configuration as shown in FIG. 1 has been proposed depending on the moldability of the positive electrode active material and the sealing state.

In Figure 1, 1 is a positive electrode can, 2 is a sealing plate, 3 is a negative electrode active material, 4 and 5 are separators, 6 is a positive electrode active material, γ is an insulating sheet, 8 is an insulating backing, 9' is a current collector shows.

A metal net is used as a current collector for this battery.

In the battery having the above-mentioned conventional structure, since divalent silver oxide has strong oxidizing power, self-discharge is large due to oxidation of the separator facing the top and side surfaces of the positive electrode active material molded body and permeation of silver acid ions.

In addition, the separator portion facing the peripheral edge of the positive electrode active material molded body is mechanically strong and comes into contact with the metal net and the positive electrode active material, so the separator is easily oxidized and easily cut, causing short circuits.

The present invention solves the above problems and suppresses self-discharge by improving the current collector structure.

That is, in the present invention, as described above, the current collector of the positive electrode is arranged at the center of the positive electrode can through a gap with the can side wall and with the bottom of the can through an insulating layer, and the current collector is placed in the center of the positive electrode can with a gap between the can side wall and the insulating layer. A continuous metal plate is placed on the inner bottom surface or side wall of the positive electrode can through the gap between the positive electrode and the insulating backing.

The present invention will be explained below with reference to examples thereof.

FIG. 2 shows an embodiment of the present invention, where 9 is a current collector, which is made of a donut-shaped nickel plate with an inner diameter of 8.5 M, an outer diameter of 10.9 mm, and a thickness of 0.1 rIvIL.

This current collector 9 is continuous from the upper surface periphery of the positive electrode 6 to the inner bottom surface of the positive electrode can 1 via the gap between the positive electrode and the insulating backing 8.

In this example, the periphery of the inner bottom surface of the can 1 is not covered with the insulating layer 7 and the current collector 9 is in contact with the can bottom, but if the entire inner bottom surface of the can is covered with the insulating layer 7, the current collector 9 will be in contact with the can bottom. The electric body 9 is brought into contact with the side wall of the can.

According to the above configuration, the metal plate 9 is disposed in a portion where the upper peripheral surface of the positive electrode 6 and the separator 5 are in strong contact with each other in the sealed state, and at the same time the separator 5 is strained and silvery acid ions easily permeate. Therefore, since the separator 5 and the upper peripheral surface of the positive electrode 6 do not come into direct contact with each other, self-discharge is small and no short-circuit phenomenon occurs.

Table 1 compares the self-discharge rates of conventional battery A with the configuration shown in Figure 1 and battery B of the present invention with the configuration shown in Figure 2 when stored at a temperature of 60°C for 20 days. It is.

The battery size is 11.6m in diameter and 2ran in total height, heavy zinc powder is used as the negative electrode active material, and 8m is used as the electrolyte.
A caustic potassium aqueous solution of N was used.

As is clear from this result, the battery of the present invention has a lower self-discharge rate than the conventional battery.

Furthermore, if the storage is continued for 40 days at 60°C, battery A
A short phenomenon occurred in 2 out of 10 cells, but battery B
There was no short circuit phenomenon.

FIG. 3 shows another embodiment of the present invention, in which a foam-like structure having a three-dimensionally continuous skeleton on the upper surface of the positive electrode 6 has a thickness of 0.5 mm.
15myn, diameter 9. It has a structure in which an OB disk-shaped silver sheet 10 is closely attached, and a current collector metal plate 9 is placed thereon.

According to this structure, the current collecting area of the positive electrode is increased by the silver layer, so that the high rate discharge characteristics are improved.

For such a silver layer, in addition to using a three-dimensional porous silver sheet as shown above, a part of the positive electrode is reduced near the current collector by performing preliminary discharge after manufacturing the battery with the structure shown in Figure 2. A silver layer may be formed.

Table 2 shows the battery B, the battery C1 obtained by pre-discharging battery B equivalent to 5 mAh, and the battery having the configuration shown in FIG.
This is a comparison of the voltage after 20 seconds when discharging with a current of 10 mA.

The above results show that batteries C and D are superior to battery B in high rate discharge.

This is due to the fact that the current collecting area is increased by providing a silver layer on the surface of the positive electrode or a part of the positive electrode.

In addition, the self-discharge rate of batteries C and D during high-temperature storage is 6
0'C, after storage for 20 days, battery C is 3-5, D is 2-4
There were many.

As described above, according to the present invention, a silver oxide battery with low self-discharge can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a conventional silver oxide battery, and FIGS. 2 and 3 are longitudinal sectional views showing an example of the structure of the silver oxide battery of the present invention. 1...Positive electrode can, 2...Sealing plate, 3...
...Negative electrode, 4...Liquid-containing material, 5...
Separator, 6... Positive electrode, T... Insulating layer, 8... Insulating backing, 9, 9'...
... Current collector, 10... Three-dimensional porous silver.

Claims (4)

[Scope of utility model registration request] (1) A positive electrode can, and a positive electrode mainly composed of divalent silver oxide, which is arranged approximately in the center of the positive electrode can with a gap between the positive electrode can side wall and the positive electrode can.
an insulating layer that isolates the inner bottom surface of the positive electrode can and the positive electrode; a negative electrode;
A separator that separates the positive electrode and the negative electrode, a sealing plate, and an insulating backing that insulates the sealing plate and the positive electrode can are provided, from the peripheral surface of the positive electrode facing the negative electrode through the gap between the positive electrode and the insulating backing. A silver oxide battery characterized in that a continuous metal plate is disposed on the inner bottom surface or side wall of the positive electrode can, and the positive electrode and the positive electrode can are electrically connected by the metal plate. (2) The silver oxide battery according to claim 1, wherein a silver layer is provided between the metal plate and the positive electrode. (3) The silver oxide battery according to claim 2, wherein the silver layer is a silver layer obtained by reducing a part of the positive electrode active material. (4) The silver oxide battery according to claim 2, wherein the silver layer is a three-dimensional porous silver sheet.