JPH0619993B2 - Zinc alkaline battery - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a zinc alkaline battery, and more specifically, to a zinc alloy containing at least one selected from indium and thallium and cobalt and nickel in a specific range, or selectively converted into a zinc alloy. The present invention relates to a zinc alkaline battery used as a negative electrode active material for a battery.

(Background of the Invention) In an alkaline battery or the like using zinc as a negative electrode active material, a strong alkaline electrolyte such as an aqueous potassium hydroxide solution is used, and therefore the battery must be sealed. This sealing of the battery is particularly important for miniaturization of the battery, but at the same time, it confine hydrogen gas generated by corrosion of zinc during battery storage. Therefore, the gas pressure inside the battery increases during long-term storage, and there is a danger of explosion and the like if the sealing is perfect.

As a countermeasure against this, research has been conducted to prevent corrosion of zinc, which is the negative electrode active material, to reduce the generation of hydrogen gas inside the battery, and to use zinc hydride, which utilizes the hydrogen overvoltage of mercury, as the negative electrode active material. Has been done. For this reason, the negative electrode active material for alkaline batteries currently on the market contains a large amount of mercury of about 5 to 10% by weight. It has become strongly expected.

Therefore, various proposals have been made regarding a zinc alloy powder in which various metals are added to zinc in order to reduce the mercury content in the battery. For example, there is a zinc alloy powder in which lead is added to zinc, or a zinc alloy powder in which lead and indium are added to zinc by the present inventors (JP-A-58-181266). However, although these zinc alloy powders have some gas generation suppressing effect, they are not yet sufficient.

As described above, a battery that reduces the amount of hydrogen gas generated while keeping the zinc alloy powder, which is the negative electrode active material, at a low level and maintains the discharge performance, which is the battery performance, at a high level has not yet been obtained.

(Object of the Invention) In view of the present circumstances, the present invention provides a zinc-alkaline battery using a negative electrode active material that significantly reduces the content of mercury, suppresses hydrogen gas generation, and maintains discharge performance at a high level. The purpose is to do.

(History of the invention) As a result of intensive research aimed at achieving this object, the present inventors have found that by adding at least one selected from indium and thallium, and cobalt and nickel in a specific range to a negative electrode active material made of zinc. The present inventors have found that the synergistic effect of these additive elements further reduces the hydrogen gas generation amount as compared with the conventional low-alloyed zinc alloy powder, and that a zinc alkaline battery having excellent discharge performance can be obtained and has reached the present invention. did.

(Structure of Invention) That is, the present invention is selected from indium and thallium.
0.01-0.5% by weight, 0.01-0.5% by weight cobalt, 0.01-0.5% nickel
A zinc alkaline battery is characterized by using a zinc alloy containing wt% as a negative electrode active material.

In the present invention, selected from indium and thallium 1
The zinc alloy containing at least one species and a specific amount of cobalt and nickel may be used as the negative electrode active material as it is, or may be used as the negative electrode active material after grading the zinc alloy. The mercury content in the case of conversion is less than the mercury content of the conventional negative electrode active material, that is, less than 5.0% by weight, but if the conversion rate is lowered and low pollution is considered, it is 3 It is not more than 0.0% by weight. Further, it is possible to suppress gas generation even with a small amount of around 1.0% by weight or less. In particular, in an air battery provided with an exhaust mechanism, a zinc alkaline battery provided with a hydrogen absorption mechanism, and the like, the permissible hydrogen gas generation amount is relatively large. Therefore, when the present invention is applied to such a battery, 1. A zinc alloy having a low weight reduction rate of 0% by weight or less or a weight loss-free zinc alloy is preferably used as the negative electrode active material.

The content of one or more selected from indium and thallium in the zinc alloy used for this negative electrode active material is 0.01 to 0.
5% by weight, the content of cobalt is 0.01 to 0.5% by weight, and the content of nickel is 0.01 to 0.5% by weight. If the content of one or more selected from indium and thallium and the content of cobalt and nickel are less than the respective lower limits, the effect of the present invention cannot be obtained, and if it exceeds the upper limit, self-discharge proceeds like zinc containing impurities.
Good results cannot be obtained for suppressing gas generation and discharging performance.

Although the action and effect of each of these additional elements have not been sufficiently clarified, it is presumed that indium and thallium contained in the zinc alloy have an action of increasing hydrogen overvoltage, and cobalt and nickel have corrosion resistance themselves. Although it is known to be a metal, it is thought to be useful for suppressing the local corrosion reaction even when it is solutionized with zinc. In addition, when the zinc alloy is modified from the surface, cobalt and nickel, which have a low affinity for mercury, suppress the diffusion of mercury into the zinc alloy and maintain a high mercury concentration on the surface of the zinc alloy to improve corrosion resistance. Thought to be useful.

The present invention provides a zinc alloy having good corrosion resistance without deteriorating discharge characteristics due to the synergistic effect of each of these actions.

Thus, the zinc-alkaline battery of the present invention uses caustic potash as an electrolytic solution, an aqueous alkaline solution containing caustic soda as a main component, the above-mentioned zinc alloy or delayed zinc alloy as the negative electrode active material, and manganese dioxide as the positive electrode active material. It can be obtained by using silver oxide, oxygen or the like.

(Explanation of Examples) Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples.

Examples 1 to 8 and Comparative Examples 1 to 10 Zinc ingots having a purity of 99.997% or more are melted at about 500 ° C., and the indium, cobalt, and nickel contents are each 0.05 wt% as shown in Table 1. To make a zinc alloy, and add this to high pressure argon gas (jet pressure
It was pulverized using 5 kg / cm ² ). Potassium hydroxide on Tsu 1
Mercury was added to the above powder in a 0% alkaline solution so as to be 1.0% by weight, and a grading treatment was performed to obtain a zinc alloy powder (Example 1).

In addition, as shown in Table 1, 1): 0.05% by weight thallium, 0.05% by weight cobalt, 0.05% by weight nickel (Example 2), 2): indium 0. 01 wt%, cobalt 0.01 wt%, nickel 0.01 wt% (Example 3) 3): thallium 0.01 wt%, cobalt 0.01 wt%, nickel 0.01 wt% (Example 4) 4): indium 0.5% by weight, cobalt 0.5% by weight, nickel 0.5% by weight (Example 5), 5): thallium 0.5% by weight, cobalt 0.5% by weight,
Nickel 0.5 wt% (Example 6), 6): Indium 0.05 wt%, thallium 0.05 wt%, cobalt 0.05 wt%, nickel 0.05 wt% (Example 7), 7) : Indium 0.2% by weight, thallium 0.3% by weight, cobalt 0.5% by weight, nickel 0.5% by weight (Example 8), 8): indium 0.05% by weight (Comparative Example 1), 9 ): Thallium 0.05 wt% (Comparative Example 2), 10): Indium 0.05 wt%, Cobalt 0.05 wt% (Comparative Example 3), 11): Indium 0.05 wt%, Nickel 0.05 Wt% (Comparative Example 4), 12): 1.0 wt% indium, 0.05 wt% cobalt, 0.05 wt% nickel (Comparative Example 5), 13): 0.005 wt% indium, cobalt 0.1. 05
Wt%, nickel 0.05 wt% (Comparative Example 6) 14): indium 0.05 wt%, cobalt 1.0 wt%, nickel 0.05 wt% (Comparative Example 7), 15): indium 0.05 Wt%, cobalt 0.005
%, Nickel 0.05% by weight (Comparative Example 8) 16): indium 0.05% by weight, cobalt 0.05% by weight, nickel 1.0% by weight (Comparative Example 9), 17): indium 0.05 % Zinc, 0.05 wt.% Cobalt, and 0.005 wt.% Nickel (Comparative Example 10). Zinc alloys were prepared, respectively, which were pulverized by the same method as described above and subjected to a grading treatment to contain mercury. A zinc alloy powder (Examples 2-8 and Comparative Examples 1-10) having a rate of 1.0% by weight was obtained.

A hydrogen gas generation test was performed using the zinc alloy powder thus obtained, and the results are shown in Table 1. In the gas generation test, 5 ml of 40 wt% potassium hydroxide aqueous solution saturated with zinc oxide was used as electrolyte, and 10 g of zinc alloy powder was used at 45 ° C for 50 days to generate gas (ml / G) was measured.

In addition, the battery performance was evaluated using the alkaline manganese battery shown in FIG. 1 with these zinc alloy powders as the negative electrode active material. The alkaline manganese battery of FIG. 1 is composed of a positive electrode can 1, a positive electrode 2, a separator 3, a negative electrode 4 obtained by gelling zinc alloy powder with carboxymethyl cellulose, a negative electrode current collector 5, a rubber packing 6, and a pressing plate 7. . Using this alkaline manganese battery, the discharge duration was measured up to an end voltage of 0.9 V under a discharge negative electrode of 4Ω and a discharge condition of 20 ° C., and the measured value of Comparative Example 11 described below using a conventional negative electrode active material was 100.
It was shown by the index. The results are shown in Table 1.

Comparative Example 11 In the same manner as in Example 1, 5.0% by weight of mercury was added to zinc, which was conventionally used.
11) got. This was subjected to a hydrogen gas generation test and a battery performance test in the same manner as in Example 1, and the results are shown in Table 1.

As shown in Table 1, Examples 1 to 8 using zinc halide alloy powder prepared by adding one or more kinds selected from indium and thallium to zinc and a specific amount of cobalt and nickel to make them negative electrode active materials. Compared to Comparative Examples 1 to 10 and Comparative Example 11 in which a zinc halide alloy powder that is conventionally used in which only mercury is added to zinc is used as the negative electrode active material, the hydrogen gas generation suppressing effect is large, and the discharge performance is high. Also proves to be excellent.

(Effect of the invention) As described above, it is selected from indium and thallium.
The zinc-alkaline battery of the present invention, which is a zinc alloy containing one or more kinds and cobalt and nickel in a specific range as it is, or is used as a negative electrode active material, improves battery performance while suppressing the hydrogen gas generation rate. Is possible
In addition, the low or no content of mercury is in line with social needs. Therefore, the zinc alkaline battery of the present invention can be used in a wide range of applications.

[Brief description of drawings]

FIG. 1 shows a principle diagram of an alkaline manganese battery according to the present invention. 1: positive electrode can, 2: positive electrode, 3: separator, 4: negative electrode,
5: Negative electrode current collector, 6: Rubber packing, 7: Press plate.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Ryoji Okazaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor, Kanji Takada 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Akira Miura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A total of 0.01 to 0.5% by weight of at least one selected from indium and thallium and 0.01 of cobalt.
A zinc-alkaline battery characterized by using a zinc alloy containing 0.5 to 0.5% by weight and 0.01 to 0.5% by weight of nickel as a negative electrode active material. 2. The zinc alkaline battery according to claim 1, wherein the zinc alloy is modified.