JPS5873951A - Thin alkaline battery - Google Patents

Abstract

PURPOSE:To obtain a thin alkaline battery with excellent quality, which can be used as a power source for an ultra-thin electronic apparatus such as an electronic watch or an electronic table computer, by suppressing the amalgamation of a gold plating by additing Co to the gold or gold alloy of a cathode can. CONSTITUTION:In the figure, a cathode can of this invention, the entire surface of which is plated with a gold alloy added with Co, is illustrated. A thin alkaline battery is manufactured by using such a plated cathode can, according to an assembly method which is similar to that of the conventional battery. In this example, silver (II) oxide is used as a positive active material, and 25% NaOH is used as an electrolyte. The added amount of Co is varied according to the following 5 levels; 0, 0.5, 1.0, 1.5 and 2.0 (wt%). As the result of analysis performed on liquid-leakage resistance test result and self-discharge test result, it was found that an excellent leakage-resistant performace and a high preservation performance are achieved when the added amount of Co is below 1.0%.

Description

[Detailed description of the invention] The present invention relates to improvements in thin-section alkaline batteries.

More specifically, the object is to provide a thin alkaline battery with better leakage resistance than K by adding Oot to the dead metal alloy by disposing it on the entire surface or a part of the cathode can. In recent years, with the development of various small electronic devices such as electronic watches, calculators, cameras, and hearing aids, sealed alkaline batteries have been attracting more and more attention, and the demand for them has increased by 1%. Botashi to %! 1! Improvements in the performance of silver oxide batteries have made a major contribution, and together with the reduction of 11KN, small and thin I! The use of batteries contributes to making these devices smaller and thinner. Fil D as a battery
sm thickness is the mainstream, and batteries with outer diameters from 1t6cm to 48mm are available in four types. Kasen (i), Kenka II (Wamerui #i anode can containing anode active material made of internationalized mercury, 5 #i separator, 4
6 is a cathode can filled with 5 tubes of a cathode active material whose main component is frozen zinc, and 6 is a gasket that doubles as insulation and sealing. K11m1 more than 2.0■! In the case of #i, the thickness of the anode active material becomes extremely thin, making it difficult to mold the anode active material, and the height of the folded part of the cathode can becomes extremely short, resulting in poor alil I resistance. There are few flaws that spoil it.

Furthermore, with this structure, it was impossible to produce a battery with a thickness of one strip. Therefore, a battery as shown in FIG. 2 has been proposed and is known, for example, in Japanese Patent Application Laid-Open No. 55-48048. 1 is a good anode can with N1 or iron KN1 plating, 2 oxide silver oxide (■),
It is an anode active material mainly composed of internationalized silver (seal) or fused water at, and is formed into a pellet shape and placed in the center of the anode can 1.

A 5 #i separator is shaped into a three-dimensional shape, is incorporated from the top surface of a pellet-shaped anode active material, and is filled with a cathode active material 5 whose main component is zinc hydride in a cathode can having a 4Fi72 inch part. The separator is integrated with a gasket 6, which has a more rigid structure, which is pressed against the periphery of the inner bottom of the anode can, and the separator is pushed into the anode can, and the tip of the anode can is crimped with a crimp mold to seal the anode can. In such a structure, the conventional battery structure as shown in FIG. 1 is the same as tK2.
The moldability of the positive electrode active material is less than 0■ compared to 9 batteries.

Alternatively, the leakage resistance of the battery has been slightly improved, but it is 2.0■
When compared with the thick battery of K11-1, the leakage resistance is insufficient and not satisfactory. This is because with such a structure, it is almost impossible to compress the bottom of the gasket 6, so the alkaline electrolyte quickly creeps up to the part 4m in Figure 113, making it difficult to compress the gasket from now on. Even if you strengthen the caulking with a cling to increase the strength, the thickness of the cathode can is also thin to make the battery thinner (thinner), so the strength is weaker, so if the 7 langes sag inward, the gasket may be pulled in easily. and the path to the outside is short, so it is ineffective (leakage resistance is poor and good, so leakage resistance t''
I tried using gold plating to improve it.

There are references in the literature that gold plating has excellent leakage resistance. However, since gold plating is expensive,
It is satisfactory even without #i gold plating with batteries of O- or above (because it provides leakage resistance, #1 is rarely used)
is the current situation. Actually, in the battery structure shown in No. 211, 1.
When the entire surface of the cathode can of a 2-inch thick battery was plated with gold or more than lalμ, the leakage resistance was significantly improved compared to a battery without gold plating. Analyzing the experimental results, the contribution rate is 7.
0chi''.

I was disappointed with the above. It is true that the effect of gold plating is tremendous, but another problem has arisen, and that is that the #L-plated surface is amalgamated.

As everyone knows, gold is a metal that is highly susceptible to amalgamation. If it is used in batteries.

It reacts with mercury in frozen zinc, which is the main component of the cathode mixture, and is amalgamated. The worst ones are amalgamated and can be clearly seen with the naked eye after a month of production. Also, since this amalgamation is progressive, the 0. This amalgamation phenomenon is a problem similar to electrolyte leakage, and if a part or the entire surface of the cathode can becomes amalgamated when replacing the battery, it will cause a feeling of anxiety (for 8) when handling the battery. I end up giving.

The present invention eliminates these drawbacks, and aims to provide a high-quality nine-book type alkaline battery that suppresses amalgamation of gold plating by adding K to gold or Fi-metal alloy KcO1-. . The details will be explained below based on examples.

4th rj! JIfi, Cof of the present invention: It is a cathode can completely polished with added gold alloy. Plating thickness is α
A thickness of 1μ or more was applied. Using a good cathode can plated in this way,
Manufactured using the same assembly method as the conventional battery shown in Figure 2.
In this example, the anode active material used was silver oxide 00, and the electrolyte used was 2s*MaOfi. The amount of co added was set to five levels shown in Table 1.

No. 11110o Addition amount Oot' gold alloy is already commercially available, and Co
1-2-added dangerous auto νnex 0. Co(L1~α2
There are products such as Autoronex CI with 96 addition, but in order to quantitatively evaluate the effect of If Oo addition amount in this example, ash was added at 5 levels from 0- to 200
The battery size used in this example was 9.6 mm outside and 1.2 mm in total thickness.The batteries thus manufactured were tested for AIIM resistance. The test conditions were that after being stored in a constant temperature and humidity chamber at 40° C. and a relative humidity of 90 to 95 degrees for 80 days, it was amalgamated and the critical mass was examined. Result 1
The number of tests shown in Table 112 is 100 each.

IIf Table The results of the test for clearing solution are as follows: Electron observation with a 15x magnification microscope, and if there is amalgamation in even a part of the can, it is judged as 6 or above as being defective. It is clear that as the amount of CO added increases, the amount of amalgamation decreases and the effect increases.

Next, we looked at the self-discharge rates of these batteries. The self-discharge rate was determined from the initial capacity t100 and the remaining capacity after the battery was stored at 140° C. and towed. The discharge resistance is FisOOKΩ,
Data represent the average of 24 items at each level, result t#! st
Shown in e.

As mentioned above, it is clear that as the amount of 00 added increases, the self-discharge rate increases and the capacity decreases.

Leak resistance test results and self-discharge test mat analysis results, C
It has been found that an amount of O added of #it, or less, is good for leakage resistance and storage stability.
゛Leakage resistance (here, regarding amalgamation) is improved because CO has a lower solubility in mercury than gold, so adding CO to gold suppresses amalgamation compared to pure gold. This seems to be for the purpose of 'l@□ Regarding self-emitting NK, the reason why the self-discharge rate worsens as the amount of CO increases in #1 is thought to be due to the local m1lk reaction with zinc in the cathode mixture. In this example, Although the entire surface of the cathode can was plated with gold alloy T containing KOO, it goes without saying that the same effect can be obtained by partial plating as shown in Figure 5 a and b. There is no problem at all with methods such as traps.

As mentioned above, the present invention has very good leakage resistance (including amalgamation) and excellent storage stability, making it a W1 source for ultra-thin electronic devices such as electronic watches and calculators. It can be provided as a highly reliable battery for commercial use, and its industrial value is great.

[Brief explanation of the drawing]

Figures 1, 2, and 5 are longitudinal sectional views of conventional batteries. Fig. 4 is a longitudinal cross-sectional view showing a cathode can fully plated with Kanakura brass tube according to the present invention, and Figures 'a (') and e (b) are longitudinal cross-sectional views showing cathode cans partially plated with gold alloy according to the present invention. It is. 1. Anode can, 4... Cathode can, 2...
Anode mixture, 5... Cathode mixture, 6... Separator, 6... Gasket. Applicant: Daini Seikosha Co., Ltd. Patent Attorney Mogami

Claims (2)

[Claims] (1) At least one pole can, one pole can, insulation and sealing t-
A thin alkaline battery composed of a wearable gasket and having a gold alloy added with s'jc& on the entire surface or a part of the cathode can. (2) The thin alkaline battery according to claim 1i @ 1, characterized in that the amount of Co added is less than 1 weight.