JPS6113346B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to improvements in cathode cans for small batteries.

Summary of the Invention The present invention provides a cathode can for a small battery having a bent end, by forming the end of the bent cathode can to be thinner than the other parts, and by making the bottom of this thin part flat. , the battery is made thinner and its leakage resistance is improved.

Conventional technology In recent years, as a power source for cameras, electronic watches, etc.
So-called mercury batteries, silver oxide batteries, silver peroxide batteries,
Small button batteries such as lithium batteries are becoming widely used. However, as the demand for these batteries increases, there are demands for further miniaturization, thinning, increased battery capacity, and improved leakage resistance. As batteries become smaller and thinner, the proportion of battery cans, separators, packing, etc. that do not directly contribute to the reaction increases, resulting in a decrease in the volumetric efficiency of the battery. It is natural that even small and thin batteries are required to have high capacity, and in order to achieve high capacity, the challenge is how to reduce these so-called dead spaces.

Problems to be solved by the invention However, for example, even if the battery capacity increases, it is meaningless if the leakage resistance decreases, and making the separator or packing thinner will impair battery functions such as self-discharge and leakage. Therefore, reducing these volumes is problematic.

FIGS. 1A and 1B are cross-sectional views of conventional alkaline batteries. In Figures 1A and B, 3 is an anode can, 7 is an anode mixture placed on the inner bottom of the anode can, 6 is a separator placed on the anode mixture 7, and is an oxidation-resistant porous synthetic resin film. It becomes more. 5 is a cathode mix disposed on the upper surface of the separator, and 1 is an end of the cathode mix. As shown in FIGS. 1A and 1B, conventionally, the cathode can end 1 is bent into a U-shape or an L-shape, and a packing 4 is placed outside this bent part to open the anode can 3. When the end edge is caulked inward, leakage resistance is ensured by engaging with the U-shaped or L-shaped bent portion via the packing 4. Therefore, if the overall thickness of the cathode can is made thinner, it will not be strong enough to deform the packing when caulking and sealing the opening edge of the anode can, and this will prevent liquid leakage. It will lead to problems.

In addition, it is necessary to use a strong material such as stainless steel for the cathode can, but because the shape of the cathode can with the bent part is complicated, the bottom of the bent part is often not finished horizontally. ,
As a result, the adhesion between the bottom of the cathode can and the packing,
There was a problem with airtightness, which was also a cause of leakage.

Therefore, in order to solve these conventional drawbacks, the present invention aims to reduce the thickness of the battery without reducing the leakage resistance.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention involves forming the end plate of a cathode can having a bend at the end thinner than the other parts, and making the bottom surface of this thin part flat. The structure was designed to make the battery thinner and improve leakage resistance.

Embodiments Examples of the present invention will be described below based on the drawings.

FIG. 2A is a longitudinal cross-sectional view showing an embodiment of the cathode can for a small battery according to the present invention, and shows an example in which the end portion 11 is folded back to have a U-shaped cross section. The bottom surface 13 of this end portion 11 is finished by folding the end portion into a U-shape and then being pressed using a mold or the like to make it flat, or by polishing to make it flat, so that parallelism is achieved. The end plate thickness t ₁ is the plate thickness t of the other part 12
It is designed to be thinner.

FIG. 2B shows another embodiment, and the second feature is that the end portion 21 is bent into an L-shaped cross section.
This is different from the case in Figure A. In this case too, Figure 2A
The bottom surface 23 of the end portion 21 is finished flat, and the end plate thickness t ₂ is the same as that of the other portion 2.
It is formed to be thinner than the plate thickness t of No. 2.

In the present invention, as shown in FIG. 2A or B, the thickness of the U-shaped or L-shaped end of the cathode can is made thinner than the other parts, so the packing and separator stacked there do not have to be made thinner. However, the thickness of the battery can be reduced. Reducing the thickness of the plates other than the ends also reduces the strength of the cathode can, but
Since the cathode can according to the present invention has a structure in which only the end portion thereof is formed thin and can withstand strong sealing pressure, the leakage resistance does not deteriorate.

Furthermore, since the bottom surface of the bent part at the bottom of the cathode can is formed flat by pressing, polishing, etc., it is possible to improve the adhesion and airtightness between the bottom of this bent part and the packing, dramatically improving leakage resistance. can be done.

Effects of the Invention As described above, since the cathode can for a small battery of the present invention is made thin only at its ends, the battery can be made smaller and thinner, the battery capacity can be increased, and the strength of the cathode can can be increased. It doesn't lower it either.
Therefore, when sealing the battery by caulking the opening periphery of the anode can, sufficient sealing pressure can be applied without causing a drop in leakage resistance.

Furthermore, since the bottom surface of the cathode can end is formed flat, the adhesion and airtightness between the bottom surface of the cathode can end and the gasket can be extremely strong, and leakage resistance can be improved.

[Brief explanation of drawings]

Figures 1A and 1B are cross-sectional views of conventional alkaline batteries.
FIGS. 2A and 2B are longitudinal sectional views showing different embodiments of the cathode can of the present invention, respectively. 11, 21... end, 12, 22... other parts, 13, 23... bottom surface.

Claims (1)

[Claims] 1. A cathode can for a small battery, characterized in that the end plate of the cathode can having a bend at the end is formed thinner than the other parts, and the bottom surface of this thin part is made flat.