JPH0883597A - Silver oxide battery - Google Patents

Abstract

PURPOSE: To provide a silver oxide battery by which capacity reduction by storage is hardly caused by restraining a utilization factor of zinc after storage caused by excessive absorption of electrolyte of an electrolyte absorbing body. CONSTITUTION: A silver oxide battery is provided with a positive electrode 1 using a silver oxide as a positive electrode active material and a negative electrode 2 using zinc as a negative electrode active material. An electrolyte absorbing body 4 having basic weight of 10 to 35g/m<2> is used, and the electrolyte absorbing body 4 is arranged between the negative electrode 2 and a separator 3.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a silver oxide battery,
More specifically, it relates to improvement of the electrolyte solution absorber.

[0002]

2. Description of the Related Art In a silver oxide battery, as shown in FIG. 1, an electrolytic solution absorber 4 is arranged between a positive electrode 1 and a negative electrode 2 together with a separator 3, and the electrolytic solution absorber 4 is filled with the electrolytic solution. Let it absorb,
By preventing water from drying during storage and smoothing the discharge reaction, the interelectrode distance is kept long to improve the ability to prevent migration of silver ions.

As the above-mentioned electrolytic solution absorber, vinylon-rayon mixed paper is usually used, and from the viewpoint of holding as much electrolytic solution as possible, the basis weight is 50.
The thing of about g / m ² is used.

However, as batteries become smaller and thinner,
Since the effective internal volume of the battery becomes small, the following problems (1) to (4) occur.

When an electrolyte solution absorber having a large grammage as described above is used, the electrolyte solution absorber absorbs too much electrolyte solution, and the free electrolyte solution is reduced. Therefore, zinc is used after storage. The rate decreases and capacity shortage occurs.

However, if the electrolyte solution absorber is not used,
Although the free electrolyte is increased, the separator 3 comes into direct contact with the annular gasket 7, and the separator 3 is annularly closed by tightening the opening end 5a of the positive electrode can 5 at the time of sealing. It is pressed against the positive electrode 1 by the gasket 7 and adheres to the peripheral portion of the positive electrode 1 to increase the migration of silver ions in that portion, and silver is intensively deposited in that portion, which accumulates during storage. , Cause an internal short circuit.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the occurrence of insufficient capacity after storage due to excessive absorption of the electrolyte solution by the electrolyte solution absorber in the small and thin silver oxide batteries as described above, It is an object of the present invention to provide a silver oxide battery that has a small capacity loss due to storage.

[0008]

According to the present invention, as a result of various studies on the basis weight of an electrolyte solution absorber used for small and thin silver oxide batteries, an electrolyte solution having a basis weight of 10 to 35 g / m ² is obtained. The present invention has been completed by finding that when an absorber is used, the utilization rate of zinc does not decrease even after storage, and thus a silver oxide battery with less capacity reduction due to storage can be obtained.

That is, if the electrolyte solution absorber has a basis weight as described above, the electrolyte solution absorber does not excessively absorb the electrolyte solution even in small and thin batteries, and as a result, after storage, In addition, a decrease in the zinc utilization rate is suppressed, and a silver oxide battery with less capacity loss due to storage can be obtained.

In the present invention, the basis weight of the electrolyte solution absorber to be used is specified to be 10 to 35 g / m ² as described above. This is because the basis weight of the electrolyte solution absorber is 10 g / m ² . This is because when the size is reduced, unevenness is generated, the ability to inhibit the transfer of silver ions is reduced, and fluff occurs when punching into a battery size, and the basis weight of the electrolyte solution absorber is 35 g / m 2.
^If it is larger than ² , the electrolytic solution absorber absorbs the electrolytic solution too much and the free electrolytic solution is reduced, so that the utilization rate of zinc decreases after storage and a capacity defect occurs. The basis weight of the electrolyte solution absorber is particularly 10
30 g / m ² is preferred.

The material of the electrolyte solution absorber is not particularly limited, but normally, a vinylon-rayon mixed paper-made paper, a polypropylene or nylon electrolyte solution absorber, etc. are used as in the prior art. To be

In the present invention, a small or thin type silver oxide battery is targeted, but when it is shown by a specific number, a button type silver oxide battery having a diameter of 9.5 mm or less and a thickness of 16. It is intended for thin silver oxide batteries of 8 mm or less.

[0013]

EXAMPLES Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to only those examples.

Example 1 Using a vinylon-rayon mixed paper having a basis weight of 15 g / m ² as an electrolyte solution absorber, a silver oxide battery having the structure shown in FIG. 1 was produced.

The battery shown in FIG. 1 will be described. In the figure, 1 is a positive electrode, 2 is a negative electrode, 3 is a separator, 4 is an electrolyte solution absorber, 5 is a positive electrode can, 6 is a negative electrode terminal plate, and 7 is a ring. It is a gasket.

The positive electrode 1 is a mixture powder composed of 95 parts by weight of silver oxide (Ag ₂ O) (parts by weight; the same applies hereinafter) and 5 parts of phosphorous graphite, and is molded by pressure. The negative electrode 2 is made of polyacrylic acid. It is composed of zinc amalgamate which is made into a paste with an electrolytic solution by adding soda.

The separator 3 is made by laminating a graft film obtained by graft-polymerizing methacrylic acid on crosslinked low-density polyethylene with cellophane in the center, and is placed on the positive electrode 1 to absorb the electrolyte solution. 4 is made of vinylon-rayon mixed paper having a basis weight of 15 g / m ² as described above, and is arranged between the separator 3 and the negative electrode 2.

The positive electrode can 5 is made of iron and its surface is nickel-plated, and the negative electrode terminal plate 6 is tin-plated (formed on the surface of the copper layer).
A steel-nickel three-layer clad plate with a peripheral edge 6
a is folded back. The annular gasket 7 is made of nylon 66, and is pressed inwardly to the peripheral edge portion 6a of the negative electrode terminal plate 6 by tightening the opening end portion 5a of the positive electrode can 5 inward, so that the positive electrode can 5
The opening is sealed. Then, into this battery was injected an electrolytic solution consisting of a 35 wt% potassium hydroxide aqueous solution in which 5.2 wt% of zinc oxide was dissolved, and the battery had a diameter of 9 m.
It is a button type battery having a height of m and a height of 20 mm.

Assembly of this battery is performed as follows. First, the positive electrode 1 is inserted into the positive electrode can 5, a part of the electrolytic solution is injected, and then the separator 3 and the electrolytic solution absorber 4 are sequentially placed thereon. Separately from this, the negative electrode 2 is put in the negative electrode terminal plate 6 having the annular gasket 7 fitted in the peripheral edge portion 6a, and the remaining electrolytic solution is injected, and the negative electrode terminal plate 6 and the positive electrode can 5 in the above state are fitted together. Then, the opening end 5a of the positive electrode can 5 is tightened inward to close the opening of the positive electrode can 5 and finish the state shown in FIG.

Example 2 As an electrolyte absorber, vinylon-ray having a basis weight of 23 g / m ²
A silver oxide battery was produced in the same manner as in Example 1 except that Yong mixed paper was used.

Example 3 As an electrolyte absorber, vinylon-ray having a basis weight of 30 g / m ²
A silver oxide battery was produced in the same manner as in Example 1 except that Yong mixed paper was used.

Comparative Example 1 Vinylon-ray having a basis weight of 50 g / m ² as an electrolyte absorber
A silver oxide battery was produced in the same manner as in Example 1 except that Yong mixed paper was used. The battery of Comparative Example 1 uses a vinylon-rayon mixed paper having a basis weight of 50 g / m ² which is used in a conventional battery as an electrolyte absorber, and corresponds to a conventional battery.

The batteries of Examples 1 to 3 and the battery of Comparative Example 1 were stored at 60 ° C. for a predetermined period, the discharge capacity was measured after each storage period, and the capacity retention ratio to the discharge capacity before storage was examined. The results are shown in Table 1. The discharge capacity was measured by performing constant resistance discharge of 15 KΩ at 20 ° C. and by maintaining the final voltage up to 1.4 V. In addition, Table 1
Shows the number of days before storage before storage.

[0024]

[Table 1]

As shown in Table 1, the batteries of Examples 1 to 3 had a large capacity retention after storage and excellent storage characteristics, as compared with the battery of Comparative Example 1 corresponding to the conventional battery.

The results show that in the batteries of Examples 1 to 3, the electrolytic solution was not absorbed too much by the electrolytic solution absorber, and the free electrolytic solution was appropriately present even after storage and the zinc utilization rate was high. It is thought that this is because the decrease in

Next, the results of examining the closed circuit voltage characteristics of the batteries of Examples 1 to 3 will be shown.

That is, the discharge depth of 0% (that is, the initial stage of discharge), the discharge depth of 40%, and the discharge depth of 80% for each of the batteries of Examples 1 to 3 and the battery of Comparative Example 1 at -10 ° C. At times, the closed-circuit voltage when discharged at 200Ω for 5 seconds was measured. The results are shown in Table 2 as the average value of each battery.

[0029]

[Table 2]

As shown in Table 2, the batteries of Examples 1 to 3 have almost the same closed circuit voltage as that of the battery of Comparative Example 1, and a large closed circuit voltage is obtained by reducing the basis weight of the electrolyte solution absorber. No decrease in voltage characteristics was observed.

[0031]

As described above, in the present invention, the use of the electrolyte solution absorber having a specific basis weight reduces the utilization rate of zinc after storage due to excessive absorption of the electrolyte solution in the electrolyte solution absorber. It has been possible to provide a silver oxide battery that is suppressed and has a small capacity decrease due to storage.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a silver oxide battery of the present invention.

[Description of sign]

 1 Positive electrode 2 Negative electrode 3 Separator 4 Electrolyte absorber

Claims (1)

[Claims] 1. A silver oxide battery provided with a positive electrode 1 using silver oxide as a positive electrode active material and a negative electrode 2 using zinc as a negative electrode active material, wherein a basis weight of 10 is provided between the negative electrode 2 and the separator 3. ~ 3
A silver oxide battery comprising an electrolyte solution absorber 4 of 5 g / m ² .