JPS59111250A - Small size alkali-manganese battery - Google Patents

Abstract

PURPOSE:To prevent battery breakdown by gastric juice if a chile gulps a battery and prevent leak of melted harmful materials by providing a nickel layer at the external surface of positive can consisting of a high chromium stainless steel containing the specific amount of chromium. CONSTITUTION:Content of chromium of a high chromium stainless steel to be used for positive can 1 is set to 23% or more and a nickel layer 8 is formed at the external surface thereof for actual use. For example, a single side of high chromium stainless steel SUS447J1 in the thickness of 0.25mm. is plated by nickel and the nickel layer 8 is placed in the external surface of can. An LR43 type battery having the stucture as shown in the figure is assembled using the positive can 1 as described above. When the nickel layer 8 exists at the external surface of positive can 1, the nickel melting reaction precedes at a less noble voltage than the melting voltage of hexavalent chromium ion. Therefore, meltiing of hexavalent chromium ion which is harmful for human body is supressed and amount of leak can be reduced drastically.

Description

[Detailed Description of the Invention] Highly safe product with improved corrosion resistance of the positive electrode can, which prevents the battery from being destroyed by gastric juices even if accidentally swallowed by an infant, etc., and prevents the elution of harmful substances from the battery. The purpose is to provide small-sized alkaline manganese batteries.

Recently, with the spread of battery-powered devices such as Game Iso and Game Quo Sochi for children, there have been many accidents in which young children accidentally swallow batteries.

Therefore, the inventors used high chromium stainless steel with a chromium content of 28% or more (by weight, the same applies hereinafter) for the positive electrode can, thereby increasing the corrosion resistance of the positive electrode can and preventing it from being accidentally swallowed. However, the company has provided a small alkaline battery that is not susceptible to destruction by gastric juices before being excreted, and has filed a separate patent application for it.

However, when high chromium stainless steel as described above is used for the positive electrode can, there is a problem in that hexavalent chromium ions (CR6+) harmful to the human body are eluted from the positive electrode can in gastric juice.

The present invention was made in view of such circumstances,
High chromium stainless steel with a chromium content of 23 or higher #By further providing a nickel layer on the outer surface of the positive electrode can,
This prevents the elution of hexavalent chromium ions from the positive electrode can, thereby preventing the adverse effects on the human body due to the use of high chromium stainless steel.

In the present invention, as a high chromium stainless steel with a chromium content of 23% or more used for the positive electrode can, for example,
447J1, SUS 829 J 1, SUS 829
Examples include J2, S U s810s, etc.

In the present invention, small alkaline manganese batteries and +-
i. A button-shaped battery, a coin-shaped or flat battery, and a cylindrical battery smaller than AAA or AAA, using an aqueous alkaline solution as an electrolyte and manganese dioxide or a mixture of manganese dioxide and mercury oxide as a positive electrode active material; refers to a small battery pack made by stacking button-shaped batteries, coin-shaped batteries, or flat-shaped batteries.

The nickel layer may be formed on the outer surface of the positive electrode can by plating, or it may be formed as a cladding material.The thickness of the nickel layer is 3μ? It is preferably n or more.

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

Example thickness 0.25 tttmO high chromium stainless steel SUS
447J1 was plated with nickel on one side, and a can was manufactured so that the nickel layer was on the outside of the can. Using this positive electrode can with a nickel layer provided on the outer surface of the can, an LR48 battery having the configuration shown in FIG. 1 was assembled. The thickness of the nickel layer was approximately 3 μm. In Figure 1, (1) is the positive electrode can, (2) is the king mixture, (3) is the annular pedestal, and (4) is the positive electrode can.
is a separator, (5) is a negative electrode material, and (6) is a copper-stainless steel made of austenitic stainless steel SUS 804 as a base material, nickel on the outer surface, and copper on the inner surface.
The negative electrode terminal plate is made of a nickel clad plate, and (7) is a nylon annular gas grip, and a nickel layer (8) is formed on the outer surface of the positive electrode can (1) as shown in Figure 2. . In this battery, zinc oxide was dissolved in 3
An alkaline electrolyte consisting of a 5-group potassium hydroxide aqueous solution is injected, and the positive electrode mixture (2) is a mixture of manganese dioxide, phosphorous graphite, and sodium polyacrylate.
Diameter 10.Tq is pressure molded at a pressure of It/ff2.
It consists of a molded body of 9 m long and 1.81 ff thick, and contains a negative electrode material (5
) is made of 110-day zinc chloride with a freezing rate of 9, and the separator (4) is a stack of cellophane and pinyon-yong mixed paper.

Control Example An LR4a type battery was constructed in the same manner as in the example except that high chromium stainless steel SUS 447J 1 was used as it was without nickel plating.

The battery obtained as described above was mixed with NaC in artificial gastric fluid (Il).
1 was immersed in 2P, 1041 (an aqueous solution containing 247 nl of C1) at 37°C for 24 hours, and the eluted hexavalent chromium ions (Cr) were measured by spectroscopic analysis. The results are shown in Table 1.

Table 1 High chromium stainless steel causes large polarization in artificial gastric fluid, so when it is used in a positive electrode can, the positive electrode can exhibits an extremely negative potential, as shown in the comparative example in Table 1. Hexavalent chromium ions, which are higher-order oxide ions of chromium, come to be eluted. However, when a nickel layer exists on the outer surface of the positive electrode can, the dissolution reaction of nickel precedes the elution potential of hexavalent chromium ions at a potential lower than the elution potential of hexavalent chromium ions. Elution of ions is suppressed, and the amount of elution is significantly reduced.

However, even if all of the nickel layer reacts and disappears, if the positive electrode active material is a homogeneously reactive material such as manganese dioxide, the battery voltage will decrease and the positive electrode potential will be lower than the potential at which hexavalent chromium ions are eluted. Therefore, the elution of hexavalent chromium ions is extremely reduced.

Note that the effect of preventing the elution of hexavalent chromium and ions by providing the nickel layer as described above is similarly exhibited in a battery using a mixture of manganese dioxide and mercury oxide as the positive electrode active material.

Next, the first cell of the above embodiment 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 placed in an artificial gastric fluid having the same composition as above at 37°C.
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.

The results are shown in Table 2. The reason why the presence or absence of battery destruction was confirmed by detecting potassium ions was because if a pinhole or the like were formed in the positive electrode can due to corrosion, the electrolyte would leak from the battery into the artificial gastric fluid.

% 2 As shown in Table 2, conventional batteries were destroyed after being immersed in the solution for 24 hours before artificial operation, but with the four ponds of the present invention, it was not only 24 hours but also after 200 hours. Even after that, no damage occurred.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an embodiment of a small alkali manganese pond according to the present invention, and FIG. 2 is an enlarged view of section A in FIG. (1)... Masao Tatsukan, (8)...Nickel) patent author Hitachi Maxell Co., Ltd. 71 Fig. 2 Fig.

Claims (1)

[Claims] 1. A small alkaline manganese 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 outer surface of the positive electrode can.