JPH0628158B2 - Zinc alkaline battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a zinc alkaline battery, more specifically, one or two selected from indium, barium and beryllium.
The present invention relates to a zinc alkaline battery in which a zinc alloy containing a seed and one or two selected from cobalt and gallium in a specific range is used as it is or after being selectively used as a negative electrode active material.

[Prior Art] 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 materials for alkaline batteries on the market today contain a large amount of mercury of about 3 to 10% by weight, and as a social need, the development of batteries with lower mercury content or with no mercury is required. 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 (JP-A-58-181266).

[Problems to be Solved by the Invention] However, although the zinc alloy powder proposed above has some gas generation suppressing effect, it has still reached a satisfactory level for reducing the mercury content to less than 3%. Absent.

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.

In view of the present situation, it is an object of the present invention to provide 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. To do.

[Means for Solving the Problems] As a result of earnest research aimed at achieving this object, the present inventors have found that in the negative electrode active material containing zinc as a main component, one or two selected from indium, barium, and beryllium. The addition of one or two selected from cobalt and gallium within a specific range allows the synergistic effect of these additive elements to generate more hydrogen gas than conventional low-alloy zinc alloy powders. The present invention has been accomplished by finding that a zinc alkaline battery having a reduced amount and excellent discharge performance can be obtained.

That is, the present invention, 0.005-0.5 wt% indium,
The negative electrode active material is a zinc alloy containing 0.005 to 0.5% by weight of the total amount of one or two kinds selected from barium and beryllium, and 0.005 to 0.5% by weight of the total amount of one or two kinds selected from cobalt and gallium. It is a zinc alkaline battery characterized by being used as.

The zinc alloy used in this negative electrode active material has an indium content of 0.005 to 0.5% by weight, and one or two selected from barium and beryllium has a content of 0.005 to 0.5% by weight and is selected from cobalt and gallium. The content of two or more species is 0.005 to 0.5% by weight, and the addition effect can be achieved with a small amount. If the content of each additive element is less than the lower limit, the effect of the present invention cannot be obtained, and if it exceeds the upper limit, self-discharge proceeds due to the adverse effect of element addition, and good effects on gas generation suppression and discharge performance are obtained. I can't get it.

The zinc alloy is used as it is as the negative electrode active material,
It is used as a negative electrode active material after the zinc alloy has been screened. If the mercury content in the case of conversion is smaller than that of the conventional negative electrode active material, that is, less than 3.0% by weight, the corrosion resistance is high. In addition, the corrosion resistance can be sufficiently secured even if the conversion rate is lowered and the mercury content is reduced to 1.5% by weight or less in consideration of low pollution. Furthermore, 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 allowable generation amount of hydrogen gas is relatively large. Therefore, when the present invention is applied to such a battery, 1.0 wt. It is also possible to use a low alloying ratio of less than or equal to% or a zinc alloy having no hydrogenation as the negative electrode active material.

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.

[Operation] Although the effects of each of these elements have not been fully clarified,
It is presumed that the indium contained in the zinc alloy has the effect of increasing the hydrogen overvoltage, and barium and beryllium have the effect of smoothing the surface of the zinc alloy, which reduces the reaction surface area and reduces the corrosion resistance. It is thought to be useful for improvement. Further, it is considered that cobalt and gallium have an effect of suppressing corrosion of zinc in the alkaline electrolyte, such as suppressing local corrosion reaction.

The present invention provides a zinc alloy excellent in both corrosion resistance and discharge performance due to the synergistic effect of each of these actions.

[Description of Examples] Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples.

Examples 1 to 19 and Comparative Examples 1 to 11 Zinc metal having a purity of 99.997% or more is melted at about 500 ° C., and the indium, barium, and cobalt contents are 0.05% by weight, respectively, as shown in Table 1. To produce a zinc alloy, which is then added with high-pressure argon gas (jet pressure 5
It was pulverized using Kg / cm ² ). Then potassium hydroxide 10
% Mercury was added to the above powder in a 0.1% alkaline solution to perform a grading treatment to obtain a zinc halide alloy powder (Example 1).

In addition, zinc gold having the composition shown in Table 1 was prepared, powdered by the same method as described above, and subjected to a screening treatment to obtain a zinc alloy powder having a mercury content of 1.0% by weight (Examples). 2 to 19 and Comparative Examples 1 to 11) were obtained.

Using the zinc hydride alloy powder thus obtained, a hydrogen gas generation test was conducted, and the results are shown in Table 1.

For the gas generation test, 5 ml of 40% by weight potassium hydroxide aqueous solution saturated with zinc oxide was used as the electrolyte.
Using 10 g of the zinc alloy powder, the gas generation amount (ml / g) at 45 ° C. for 50 days 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 includes a positive electrode can 1, a positive electrode 2, a negative electrode 3, a separator 4, a sealing body 5, a negative electrode bottom plate 6,
Negative electrode current collector 7, cap 8, heat-shrinkable resin tube 9,
It is composed of insulating rings 10 and 11 and an outer can 12. Using this alkaline manganese battery, the discharge duration up to an end voltage of 0.9 V was measured under a discharge condition of 4 Ω and a discharge condition of 20 ° C., and the measured value of Comparative Example 12 described below using a conventional negative electrode active material was set to 100. It is shown by an index. The results are shown in Table 1.

Comparative Example 12 In the same manner as in Example 1, 5.0% by weight of mercury was added to zinc, which is a conventionally used zinc halide alloy powder (Comparative Example 1
2) 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, zinc hydride prepared by adding indium to indium, one or two kinds selected from barium and beryllium, and one or two kinds selected from cobalt and gallium in a specific amount and hydrated. Examples 1 to 19 in which the alloy powder was used as the negative electrode active material were used in Comparative Examples 1 to 11 and further the zinc halide alloy powder conventionally used in which only mercury was added to zinc was used as the negative electrode active material. As compared with Comparative Example 12, it can be seen that the hydrogen gas generation suppressing effect is large and the discharge performance is excellent.

[Effects of the Invention] As described above, a zinc alloy containing indium, one or two kinds selected from barium and beryllium, and one or two kinds selected from cobalt and gallium in a specific range as it is, or The zinc alkaline battery of the present invention which has been used as a negative electrode active material can improve the battery performance while suppressing the hydrogen gas generation rate. It also meets your 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 side sectional view of an alkaline manganese battery according to the present invention. 1: Positive electrode can, 2: Positive electrode, 3: Negative electrode, 4: Separator, 5: Sealing body, 6: Negative electrode bottom plate, 7: Negative electrode current collector, 8: Cap, 9: Heat-shrinkable resin tube, 10, 11: Insulation Ring, 12: Exterior can.

 ─────────────────────────────────────────────────── ─── Continuation of the 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 amount of 0.005 to 0.5% by weight of indium and one or two selected from barium and beryllium.
A zinc-alkaline battery characterized by using as a negative electrode active material a zinc alloy containing 0.005 to 0.5% by weight and 0.005 to 0.5% by weight of a total amount of one or two kinds selected from cobalt and gallium. 2. The zinc alkaline battery according to claim 1, wherein the zinc alloy is modified.