JPS59111249A - Small size alkaline battery - Google Patents

Abstract

PURPOSE:To prevent breakdown of battery by gastric juice even if a child gulps it careleassly and also enhance electric characteristic by providing a nickel layer at the internal surface of positive can consisting of a high chromium stainless steel containing a specific amount of chromium. CONSTITUTION:Content of chromium of a high chromium stainless steel used as the positive can 1 is set to 23% or more and moreover a nickel film 8 is formed at the internal surface thereof for actual use. For example, a single side of a high chromium stainless steel SUS447J1 in the thickness of 0.25mm. is plated by nickel and a can is formed with the nickel layer 8 placed in the side of internal surface of can and the nickel layer 8 is provided in the side of internal surface of this can. An LR43 type battery is assembled in such a structure as shown in the figure using the positive can 1 as described above. A battery providing the nickel layer 8 at the internal surface of can 1 assures stable open circuit voltage or closed circuit voltage, but a battery not providing nickel layer shows drop of open circuit voltage and closed circuit voltage due to the storing.

Description

[Detailed Description of the Invention] The corrosion resistance of the can has been improved so that even if an infant or other child swallows it prematurely, it will not cause stomach g! The purpose is to prevent battery damage caused by battery damage and to improve electrical performance.

Recently, as battery-powered devices such as game consoles and game watches for children have become popular, there have been many accidents in which young children accidentally swallow batteries.

Therefore, the present inventors increased the corrosion resistance of the positive electrode can by using high chromium stainless steel with a chromium content of 23 or higher (weight range, the same applies hereinafter) for the positive electrode can, and even if it is accidentally swallowed, it will be excreted. In the meantime, we have provided a small Alka IJz pond that is not susceptible to destruction by gastric juices, and have filed a separate patent application for it.

However, when high chromium stainless steel like the one mentioned above is used for the positive electrode can, the high chromium stainless steel
! It is easily electrolytically oxidized by the positive electrode active material in the solution, and hexavalent chromium ions (Cr6+) are eluted.The eluted hexavalent chromium ions migrate to the negative electrode side and form a film on the surface of the negative electrode active material. There is a problem in that it makes the five negative active substances passivated and reduces electrical performance such as a drop in closed circuit voltage.

The present invention was made in view of such circumstances,
By providing a nickel layer on the inner surface of the positive electrode can made of high chromium stainless steel with a chromium content of 23 or more,
This prevents the elution of hexavalent chromium ions from the positive electrode can and prevents the electrical characteristics from deteriorating due to hexavalent chromium ions.

In the present invention, the chromium content used in the positive electrode can is 23%.
Examples of the above high chromium stainless steel include SUS.
447 J 1, SUS 329 J 1, SUS 3
29 J 2.5US310S etc.

Furthermore, in the present invention, small alkaline batteries include button-shaped batteries, coin-shaped or flat batteries, and cylindrical batteries smaller than AAA or AAA, as well as button-shaped batteries and coin-shaped or flat batteries. A small battery that is made up of stacked batteries.

The nickel layer may be formed on the inner surface by plating, or may be formed as a mating material for the gland plate, and the thickness of the nickel layer is preferably 3 μm or more.

Next, the present invention will be explained with reference to Examples.

Example High chromium stainless steel 5us447 with thickness 0.25ff
One side of J1 was plated with nickel, and the can was made so that the nickel layer was on the inner surface of the can. Using this positive electrode can with a nickel layer provided on the inner surface of the can, an LR43 battery having the configuration shown in FIG. 1 was assembled. The thickness of the nickel book is approximately 3
It was μm. In Fig. 1, (1) is a positive electrode can,
(2) is a positive electrode mixture, (3) is an annular pedestal, (4) is a separator, (5) is a negative electrode material, and (6) is austenitic stainless steel 5US804 as a base material, with nickel on the outside and copper on the inside. (7) is a nylon annular gasket, and a second
As shown in the figure, a nickel layer (8) is formed. An alkaline electrolyte consisting of a 35% potassium hydroxide aqueous solution in which zinc oxide is dissolved is injected into this battery, and the positive electrode mixture (2) is a mixture of manganese dioxide, phosphorous graphite, and sodium polyacrylate. Hit it/
Pressure molded with □□□2 pressure! The negative electrode agent (5) is made of zinc chloride 1109J with a fd freezing rate of 9: lj, and the separator (4) is made of cellophane and vinylon-rayon mixed paper. It's an accumulation of things.

Control Example: An LR43 type battery was assembled in the same manner as in the example except that the can was manufactured using high chromium stainless steel SUS 447 J 1' and without nickel plating.

Table 1 shows the storage test results of the batteries obtained as described above.

Table 1 (Note) The closed circuit voltage was measured after discharging for 5 seconds at 100Ω.

As shown in Table 1, the battery of the example with a nickel layer on the inner surface of the positive electrode can has stable open-circuit voltage and closed-circuit voltage, while the battery of the control example without a nickel layer has a stable As a result, the open circuit voltage and closed circuit voltage are decreasing. In particular, the decrease in closed circuit voltage is significant.

This is considered to be because the positive electrode active material and the chromium in 5US447J1 reacted and hexavalent chromium ions were eluted into the electrolyte.

Next, the battery of the above example and a conventional battery (an LR43 type battery using a positive electrode can made from an iron plate with a thickness of 0.25 mm and plated with nickel) were mixed with artificial gastric fluid (2j of NaCl in 16 mm).
37° in aqueous solution Q) containing 24 ml of 1110% HCl.
The battery was immersed in C for 24 hours, and the presence or absence of battery destruction was examined by detecting potassium ions in the artificial gastric fluid. (7) The results are shown in Table 2. The reason why we adopted a method of detecting potassium ions to confirm whether the battery was damaged or not is because if a pinhole or the like occurs in the positive electrode can due to corrosion, the electrolyte will leak from the battery into the artificial gastric fluid. .

Table 2 As shown in Table 2, conventional batteries contain 2
Although the battery was destroyed after being immersed for 4 hours, the battery of the present invention was not destroyed at all not only after 24 hours but also after 200 hours.

[Brief Description of the Drawings] Fig. 1 is a partial sectional view showing one embodiment of a small alkaline battery of the present invention, and Fig. 2 is an enlarged view of section A in Fig. 1. (1)...・Positive electrode can, (8)...Nickel layer patent applicant: Hitachi Maxell Co., Ltd. Representative Patent Attorney: Tetsuo Miwa Details: Niyama, Fumi'
: Yuip pot 1 soil 11 figure 72 figure

Claims (1)

[Claims] 1. A small alkaline battery characterized in that a high chromium stainless steel with a chromium content of 23% by weight or more is used for the positive electrode can, and a nickel layer is provided on the inner surface of the LIE electrode can.