JPS61135053A - Button type alkaline cell - Google Patents

Abstract

PURPOSE:To acquire a stable enclosed structure of cell even though the positive electrode composite is formed with a thickness less than 0.5mm, by regulating the relation of the height of the positive electrode ring and the thickness of the formed positive electrode composite. and the radius of curvature of the bottom angle of the positive electrode case, in a specific ratio. CONSTITUTION:A positive electrode composite 2 pressing-formed with a thickness less than 0.5mm, and a positive electrode ring 3 to stabilize the the composite 2, with an L shape section and a height h, less than half the thickness a of the composite 2, are housed in the positive electrode case 1 with a radius of curvature R of the inner bottom angle, as R<=(a-h). Then they are combined with the cathode composite 7 filled in the sealing plate 8, an absorbent 5 containing electrolyte, a separator 4, etc., to form a button type alkaline cell. Therefore, even though the formed positive electrode composite 2 is relatively thin, the sealing composition in sealing is stabilized, and anti-leakage property and heavy load performance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in button-type alkaline batteries.

Conventional technology Traditionally, button-type alkaline batteries have been mainly used as power sources for small electronic devices, but in recent years, with advances in electronics-related devices, batteries have become thinner.

High reliability has become important.

Conventionally, button-type alkaline batteries have had a configuration as shown in FIG. In FIG. 2, 1 is a positive electrode case, 2 is a pressure-molded positive electrode mixture, and 3 is a positive electrode ring. Here, the role of the positive electrode ring (3) is to serve as a base during sealing, not only to stabilize the sealing structure and improve leakage resistance, but also to reduce the contact resistance between the positive electrode active material and the case, which is the positive terminal, and to handle heavy loads. characteristics were improved.

However, in recent years, as batteries have become thinner, the thickness a of the positive electrode mixture has decreased to 0.
Many products with less than 5 shochu have been developed. At this time, the molding properties were unstable due to the occurrence of cracks in the molded positive electrode, so the following method was actually used.

(1) Using only a molded positive electrode as a base without using a positive electrode ring.

(2) Use a flat washer-shaped positive electrode plate.

In addition, in a battery where the thickness a of the mixture is larger than 0.5 mm, the above-mentioned problem does not occur because the positive electrode mixture itself absorbs the stress during pressure molding.

Problems to be Solved by the Invention In the conventional configurations as described in (1) and (2) above, the molded positive electrode, which is the sealing base, becomes unstable as it collapses when exposed to sunlight, making the sealing structure unstable and leak-proof. Characteristics become unstable. Further, there was a problem in that the contact with the positive electrode case, which also serves as a positive electrode terminal, became unstable, resulting in variations in heavy load characteristics, particularly in closed circuit voltage characteristics at low temperatures.

The present invention solves these problems and provides a button-type alkaline battery with excellent leakage resistance and heavy load characteristics.

Means for Solving the Problem In order to solve this problem, the present invention uses a positive electrode ring in which the relationship between the height h of the positive electrode ring and the thickness of the molded positive electrode mixture is h 謔a, and a positive electrode case. The radius of curvature R of the inner bottom corner portion is set to be an R portion (ah).

By maintaining this relationship, a stable molded positive electrode can be obtained using a cross-sectional positive electrode ring even in a battery using a molded positive electrode mixture with a thickness of 0.06 mm or less, and as a result, the leakage resistance property and A button-type alkaline battery with stable strong load characteristics can be obtained.

Embodiment One embodiment will be described with reference to FIG. Figure 1 shows a silver oxide battery 5R7 consisting of silver sulfide as a positive electrode, frozen zinc as a negative electrode, and an aqueous solution of sulfur-IJium hydroxide as an electrolyte.
It is a sectional view of 12S'W (diameter: 9wa, height: 1.2m+). In the case of this battery, in order to balance the positive and negative electrode mixtures, the thickness of the positive electrode should be 0.40 m. In a battery having such a positive electrode body, the radius of the inner bottom corner of the battery case 1 is 0.10+m, and the height h of the positive electrode ring 3 is 0.25m.

When the R of the above case was set to 0.30° C.m, it was impossible to pressurize the lotus. The reason for this is that the legs of the cathode ring with an angular cross-section hit the R part of the cathode case, and the force on the cathode mixture is not uniformly applied, causing the cathode to curve upward and
Cracks may occur.

These various experimental results are summarized as K as shown in Table 1.

Table 1: a=o, 40 square meters Table 1 shows the number of positive electrodes that were bent or cracked when pressure molded. The reason why molding is not possible in the cases ■, ■, ■, and ■ in the table is believed to be due to the above-mentioned reasons.

Next, a battery was assembled using the pressure-molded positive electrodes 1, 2, 2, and 3. Table 2 shows the test results of the low temperature closed circuit voltage characteristics.

Table 2 Table 2 shows the average value and variation of the closed circuit voltage after 6 seconds at 2Ω for each of the 20 batteries at -10°C. As is clear from this table, batteries using the positive electrodes of ■, ■, and ■ have lower average values and larger variations than those of ■, regardless of the depth of discharge. The reason for this is that the longer legs of the positive electrode ring allow for closer contact between the positive electrode body and the positive electrode case.
This is thought to be to increase the current collection effect.

In the above example, a=0.40m, h=o, 25m
+.

Although the description has been made with R=o and 10 m, according to the studies of the present inventors, good results were obtained within the range satisfying the relationship of h, R≦(ah).

Effects of the Invention As is clear from the above explanation, in a battery in which the thickness of the pressure-molded positive electrode mixture is 0.50 m or less, h≧(a,
In order to satisfy the relationship R<(a-h), the positive electrode case,
By using a positive electrode ring having a cross-sectional shape, a button-type alkaline battery with excellent leakage resistance and heavy load characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a button-type silver oxide battery according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional button-type alkaline battery. 1... Positive electrode case, 2... Positive electrode mixture,
3...Positive electrode ring, 4...Separator, 6...Impregnating material, e...Sealing ring,
7... Negative electrode, 8... Sealing plate. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure/-f stone 1T-also 2-ffi koban 3-Kazumasa

Claims (1)

[Claims] A battery that has a positive electrode mixture pressure-molded to a thickness of 0.5 mm or less in the positive electrode case and a positive electrode ring with an L-shaped cross section, and the height (h) of the positive electrode ring is the thickness of the positive electrode mixture. 1/2 or more, and the radius of curvature (R) of the bottom corner of the inner surface of the positive electrode case satisfies R≦(ah).