JPS5835346B2 - sealed small battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealed small battery used as a power source for small portable electronic devices, and particularly to a case for a small button-type battery whose height is smaller than its diameter E.

Conventional battery cases of this type are made by drawing a metal plate of a certain thickness into a cylindrical shape with a bottom, but because the thickness of the bottom is constant, when pressure is applied inside the battery, However, if the wall thickness was increased to prevent bulging, the strength would be improved, but the total height of the battery would also increase, resulting in a decrease in discharge capacity per unit volume.

In the present invention, the outer periphery of the bottom of the case is made thicker to increase the strength of the battery case, and the center and sides of the bottom are made thinner to minimize the reduction in internal volume of the case, so that the discharge capacity per unit volume is hardly reduced. Therefore, the strength against the internal pressure E can be improved by a wide range E.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

After drawing a nickel plate with a thickness of 0.5 mm into a cylinder with a bottom of 0.5 mm in bottom thickness and 0.2 mrn in side thickness, the bottom surface of a shrinking end mill was made into a cylinder with an outer circumferential thickness of 0.5 mm. 5
It was molded into a spherical surface with a center thickness of 0.1 mm.

The outer circumferential diameter is 11.5 mm, and the total height is 3.6 mm.

Into the battery case 1a which also serves as an anode lead formed by straining I, an anode mixture 2 mainly composed of silver peroxide (Ago) is placed and pressurized at a pressure of 8t0rL/d. After disposing the agent 4 and the insulating backing 5, an electrolytic solution containing an aqueous solution of caustic soda as a main component is injected.

[Next] A cathode can 7 containing a cathode mixture 6 mainly composed of zinc hydrate is inserted, and finally the upper end of the battery case 1a is crimped and sealed.

Table 1 shows the changes in the total height of the battery when the battery having the battery case of the present invention manufactured in this manner was stored at room temperature.

(Average of 10 samples for each sample) Table 1 also shows conventional batteries having a battery case 1b with a constant bottom thickness.

As is clear from Table 1, in Example A using the battery case of the present invention, the battery bulges during storage is significantly one less than in Conventional Example B, which has the same total battery height.

In addition, in the conventional example in which the bottom thickness of the battery case is increased, the bulge during storage is reduced as in Example A of the present invention, but the battery height increases by 0.2 mm, and the discharge capacity per unit volume is reduced. becomes smaller.

In the above embodiment, a battery case with a spherical bottom surface was described, but other shapes may be used, such as a stepped case (with different thickness (Fig. 2 E)), a conical case (Fig. 2 F, G), etc. ) had similar effects.

Furthermore, the battery case of the present invention is not limited to silver peroxide batteries, but is also applicable to silver-zinc secondary batteries, Ni-Cd secondary batteries, etc. Needless to say, it is widely effective in cases where there is fear.

As explained above, according to the present invention, strength against internal pressure can be improved without substantially changing the total height of the battery, and bulging of the battery during long-term storage can be prevented.

Therefore, the present invention is extremely suitable as a case for batteries that require a small size and large discharge capacity, such as batteries for electronic wristwatches.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a silver peroxide battery using the battery case of the present invention, and FIG. 2 is a partially cutaway longitudinal sectional view of the bottom of the battery case. 1...Battery case that also serves as an anode lead, 2...
... Anode mixture, 3 ... Separator, 4.
... Electrolyte impregnated material, 5 ... Insulating puffing, 6 ... Cathode mixture, 7 ... Cathode can,
1a... An embodiment of the present invention, 1b...
Conventional example, 1e...Other embodiments of the present invention, 1f
...Other embodiments of the present invention, 1g...Other embodiments of the present invention.

Claims (1)

[Claims] 1. A sealed small battery consisting of a combination of an anode can and a cathode can, characterized in that the thickness of the bottom of the anode can is thicker at the outer periphery and thinner at the center.