JPS61290653A - Zinc alkaline battery - Google Patents

Abstract

PURPOSE:To retard hydrogen gas evolution in addition to the reduction of mercury content by using zinc alloy obtained by adding a specified amount of indium, thallium, cobalt, and nickel to zinc as a negative active material of zinc alkaline battery. CONSTITUTION:A zinc alloy containing 0.01-0.5wt% indium and/or thallium, 0.01-0.5wt% cobalt, and 0.01-0.5wt% nickel is used as it is or after amalgamation as a negative active material to form a negative electrode 4. The negative electrode 4 is combined with a positive electrode 2 mainly comprising manganese dioxide, and a separator 3 to form a zinc alkaline battery. By the synergistic effect of the elements added, hydrogen overvoltage is increase and local corrosion is retarded to reduce hydrogen gas evolution. Therefore, battery performance is increased in addition to the remarkable reduction of mercury content.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a zinc alkaline battery, and more specifically, a zinc alloy containing one or more selected from indium and thallium, cobalt and nickel within a specific range, either as is or in the form of a The present invention relates to negative electrode active materials for batteries and the zinc-alkaline battery used in No. 1.

(Background of the Invention) In alkaline batteries using zinc as a negative electrode active material, a strong alkaline electrolyte such as an aqueous potassium hydroxide solution is used, so the battery must be sealed. Sealing the battery is especially important when trying to downsize the battery.
At the same time, hydrogen gas generated by corrosion of zinc during battery storage is trapped. Therefore, during long-term storage, the gas pressure inside the battery increases, and the more densely packed the battery is, the greater the risk of explosion.

As a countermeasure, research has been conducted to prevent corrosion of zinc, which is an active material for the negative electrode, and to reduce the generation of hydrogen gas inside the battery. It is being done. For this reason, the negative electrode active material of commercially available alkaline batteries is 5 to 10
They contain a large amount of mercury, on the order of % by weight, and as a social need, there are strong expectations for the development of lower mercury or mercury-free batteries.

Therefore, various proposals have been made regarding zinc alloy powders in which various metals are added to zinc in order to reduce the mercury content in batteries. For example, a zinc alloy powder made by adding lead to zinc, or a zinc alloy powder made by the present inventors by adding lead and indium to zinc (Japanese Unexamined Patent Publication No. 181266/1983) is used. However, although these zinc alloy powders have a certain degree of gas generation suppressing effect, it is still not sufficient.

As described above, a battery that reduces hydrogen gas generation m while maintaining a high level of discharge performance, which is the battery performance, while making the zinc alloy powder, which is the negative electrode active material, low in temperature has not yet been obtained.

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

(Background of the invention) As a result of intensive research in line with this purpose, the present inventors have found that one or more selected from indium and thallium, cobalt, and nickel are added in a specific range to a negative electrode active material made of zinc. The inventors discovered that the synergistic effect of these additive elements makes it possible to obtain a zinc-alkaline battery that further reduces the amount of hydrogen gas generated than conventional zinc alloy powders with low water content and has excellent discharge performance. Reached.

(Structure of the Invention) That is, the present invention contains 0.01 to 0.5% by weight of one or more selected from indium and thallium, and 0.0% by weight of cobalt.
A zinc-alkaline battery characterized in that a zinc alloy containing 1 to 0.5% of nickel and 0.01 to 0.5% of nickel is used as a negative electrode active material. 'In the present invention, the zinc alloy to which one or more selected from indium and thallium, cobalt, and nickel are added in specific amounts can be used as a negative electrode active material as it is, or used as a negative electrode active material after the zinc alloy has been converted into a liquid. . The mercury content in the case of oxidation is smaller than the mercury content in conventional negative electrode active materials.
In other words, it is less than 5.0% by weight, but when considering lower hydration rate and low pollution, it is 3.0% by weight or less. Further, gas generation can be suppressed even with a small amount of around 1.01ff1% or less. In particular, in air batteries equipped with an exhaust mechanism, zinc-alkaline batteries equipped with a hydrogen absorption mechanism, etc., the permissible amount of hydrogen gas generated is relatively large, so when applying the present invention to such batteries, 1. A zinc alloy with a bushing rate of 0% by weight or less or a zinc alloy with no growth rate 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 in this negative electrode active material is 0.01 to 0.
5% by weight, cobalt content is o, oi ~ 0.5% by weight
The effect of adding nickel is exhibited even when the content of nickel is as small as 0.01 to 0.5% by weight. If the content of one or more selected from indium and thallium, cobalt, and nickel is below the respective lower limits, the effects of the present invention cannot be obtained, and if the upper limits are exceeded, self-discharge progresses as in the case of zinc containing impurities, and gas Good results cannot be obtained in terms of generation suppression and discharge performance.

Although the effects of each of these additive elements have not been fully elucidated, it is estimated that indium and thallium contained in zinc alloys have the effect of increasing hydrogen overvoltage, and cobalt and nickel themselves have the effect of increasing corrosion resistance. Although it is known that zinc is a certain metal, it is thought that it also helps to suppress local corrosion reactions when it is dissolved in zinc. In addition, when a zinc alloy is hydrated 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, improving corrosion resistance. It is thought that it will be useful.

In the present invention, due to the synergistic effect of these respective actions, a zinc alloy with good corrosion resistance is obtained without deteriorating the discharge characteristics.

As described above, the zinc-alkaline battery of the present invention uses an alkaline aqueous solution containing caustic potash, caustic soda, etc. as the main component as an electrolyte, the above-mentioned zinc alloy or aqueous zinc alloy as a negative electrode active material, and manganese dioxide, as a positive electrode active material, Obtained by using silver oxide, oxygen, etc.

(Description of Examples) The present invention will be specifically described below based on Examples and Comparative Examples.

-1 to 8 and Comparative Examples 1 to 10 A zinc ingot with a purity of 99.997% or more was melted at about 500°C, and indium, cobalt,
A zinc alloy was prepared by adding nickel so that the content thereof was 0.05% by weight, and this was pulverized using high-pressure argon gas (ejection pressure: 5 Ny/cd). Next, in an alkaline solution of 10% potassium hydroxide, add 1
．． Mercury was added to the mixture to give a concentration of 0% by weight, and a hydrogenation treatment was performed to obtain a zinc alloy powder (Example 1).

In addition, as shown in Table 1, the following compositions were used: 1): 0.05% by weight of thallium, 0.05% by weight of cobalt, 0.05% by weight of nickel (Example 2), 2): 0% indium .01% by weight, cobalt 0.01% by weight, nickel 0.01% by weight (Example 3) 3): Thallium 0.0
1% by weight, cobalt 0.01% by weight, nickel 0.01%
Weight% (Example 4), 4): Indium 0.5% by weight,
0.5% by weight of cobalt, 0.5% by weight of nickel (Example 5), 5): 0.5% by weight of thallium, 0.5% by weight of cobalt, 0.5% by weight of nickel (Example 6), 6) 212
2960.05% by weight, 0.05% by weight of thallium, 0.05% by weight of cobalt, 0.05% by weight of nickel (Example 7), 7): 0.2% by weight of indium, 0.3% by weight of thallium.
, 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% by weight (Comparative Example 2), 10) 2122
960.05% by weight, cobalt 10, α5% by weight (
Comparative example 3), 11): Indium o, os am%, nickel 0.0
5% by weight (Comparative Example 4), 12): Indium 1.0% by weight, Cobalt 0.05% by weight, Nickel 0.05% by weight (Comparative Example 5), 13):
Indium 0.005% by weight, cobalt 0.05% by weight
, nickel 0.05% by weight (Comparative Example 6) 14) 2122
960.05% by weight, cobalt 1.0%, nickel 0.05% (Comparative Example 7), 15): Indium 0
．． 0511%, cobalt o, oos wt%, nickel 0
．． 05% by weight (Comparative Example 8) 16): Indium 0.05
11%, cobalt 0.05% by weight, nickel 1.0% by weight (comparative example 9), 11): indium 0.05% by weight, cobalt 0.05% by weight, nickel 0.005% by weight (comparison) Example 10) A zinc alloy consisting of
This was powdered in the same manner as described above, and subjected to a filtration treatment to form a zinc alloy powder with a mercury content of 1.0% by weight (Example 2).
~8 J3 and Comparative Examples 1 to 10) were obtained.

A hydrogen gas generation test was conducted using the zinc alloy powder thus obtained, and the results are shown in Table 1. The gas generation test was conducted using 5Id of potassium hydroxide aqueous solution saturated with zinc oxide with a concentration of 40% as the electrolyte and 10 g of zinc alloy powder at 45°C for 50 days. (td/Q) was measured.

Further, battery performance was evaluated using an alkaline manganese battery shown in FIG. 1 using these zinc alloy powders as a negative electrode active material. The alkaline manganese battery shown in FIG. 1 is composed of a positive electrode can 1, a positive electrode 2, a separator 3, a negative electrode 4 made of zinc alloy powder gelled with carboxymethyl cellulose, a negative electrode current collector 5, a rubber packing 6, and a pressing plate 7. Using this alkaline manganese battery, we measured the discharge duration to a final voltage of 0.9V under discharge conditions of 4Ω discharge load and 20°C.
The values are expressed as an index with the measured value of Comparative Example 11, which will be described later, using a conventional negative electrode active material set as 100. The results are shown in Table 1.

A conventionally used zinc oxide alloy powder (Comparative Example 11) in which 5.0% by weight of mercury was added to zinc was obtained in the same manner as in Example 1. 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.

Table 1 As shown in Table 1, an example in which a zinc oxide alloy powder made by adding one or more selected from indium and thallium to zinc and specific amounts of cobalt and nickel to form a oxide was used as a negative electrode active material. 1>8 has a greater hydrogen gas generation suppressing effect than Comparative Examples 1 to 10 and Comparative Example 11, which used a conventionally used zinc chloride alloy powder, in which only mercury was added to zinc, as the negative electrode active material. It can be seen that the discharge performance is also excellent.

. (Effects of the Invention) As explained above, the zinc alkaline heavy oil of the present invention uses a zinc alloy containing one or more selected from indium and thallium, cobalt, and nickel in a specific range as a negative electrode active material, either as it is or after being made into a starch. It is possible to improve battery performance while suppressing hydrogen gas generation rate,
It also meets social needs as it contains low or no mercury. Therefore, the zinc-alkaline battery of the present invention can be used in a wide range of applications.

[Brief explanation of the drawing]

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: Pressing plate. Patent applicant Mitsui Kinzoku Mining Co., Ltd. Patent applicant Matsushita Electric Industrial Co., Ltd. Agent Patent attorney Tatsuo Ito Agent Patent attorney Tetsuya Ito Figure 1

Claims (1)

[Claims] 1. A total of 0.01 to 0.5% by weight of one or more selected from indium and thallium, and 0.01 to 0.5% of cobalt.
1. A zinc-alkaline battery characterized in that a zinc alloy containing 0.01 to 0.5% by weight of nickel is used as a negative electrode active material. 2. The zinc-alkaline battery according to claim 1, wherein the zinc alloy is made of aluminum.