JPS5971259A - Alkaline storage battery and its manufacturing method - Google Patents

Abstract

PURPOSE:To manufacture an alkaline storage battery with the reduced content of Hg that suppresses the generation of H2 gas from a cathode material by using the Zn powder amalgamated with an alloy consisting of Pb, in, and Hg as a cathode active material for the battery. CONSTITUTION:Zn powder is thrown into a KOH aqueous solution and is pre- agitated. Then the Zn alloy amalgamated by pre-mixing Pb, In, and Hg is agitated while it is slowly being dropped into the said solution from a narrow hole. Subsequently, Zn-Pb-In-Hg powder is obtained by washing thus obtained alloy powder with water and drying it at low temperature and is used as a cathode active material. As a result, an alkaline storage battery with excellent performance that suppresses the generation of gas can be obtained.

Description

[Detailed Description of the Invention] The present invention relates to a method for making an alkaline battery,
Specifically, the present invention relates to an alkaline battery using an amalgamated zinc powder in which lead and indium coexist as a cathode active material for a battery, and a method for manufacturing the same.

In alkaline batteries and the like using zinc as the cathode active material, the battery must be hermetically sealed for 71 kj because a strong alkaline electrolyte with a potassium hydroxide aqueous solution aroma is used. This sealing of the battery is especially important when trying to downsize the battery, but it also traps hydrogen gas generated by corrosion of the zinc during battery storage. Therefore, during long-term storage, the gas pressure inside the battery increases, and the more completely the battery is sealed, the greater the risk of explosion. As a countermeasure against this problem, various efforts have been made to improve the structure of the battery and selectively guide the generated gas to the outside of the battery, but this is not yet perfect.

Therefore, research has been conducted into preventing corrosion of the lead cathode active material itself and reducing gas generation inside the battery, and amalgamated zinc, which utilizes the hydrogen overvoltage of mercury, has been exclusively used as the cathode active material. . However, the cathode active materials of alkaline batteries commercially available today are 5 to 1
It contains a large amount of mercury (5% culm), which poses a danger to humans and other living organisms, and is highly likely to cause environmental pollution.

Therefore, a method has been proposed in which gas generation is suppressed by using a zinc electrode to which lead or the like is added instead of using mercury.

However, although such elements have the effect of suppressing gas generation to some extent, they are still far from being able to replace mercury. A method has also been proposed in which zinc powder is immersed in a solution and amalgamation is performed by the substitution method, and at the same time lead or cadmium is added to the powder. ] However, it is not possible to reduce the mercury content.

The present invention improves the above-mentioned current situation by reducing the mercury content necessary for suppressing the generation of hydrogen scum from active materials to a minimum of 1:2. (
The purpose of the present invention is to provide an alkaline battery using alkaline batteries and a method for manufacturing the same.

The inventors designed C1() for this purpose. i1 [In addition to mercury, lead and indium coexist in the cathode active material made of bonded zinc! However, mercury, lead, and indium act synergistically to suppress gas generation, and the mercury part is more concentrated in the cathode active material made from conventionally used amalgamated zinc than in the case of adding 1'3. Even if you reduce it properly,
Amalgamated zinc 1; Z polar active material? ? ■How to use:
In some cases, the same or higher scum generation suppression effect and battery performance effect were achieved.

That is, the alkaline battery of the present invention is an alkaline 1 battery characterized by using amalgamated zinc powder in which lead and indium coexist as a cathode active material for the battery.

While the conventional cathode active material consisting of simply amalgamated zinc powder has a mercury content of 5 to 15 type parts, the cathode active material used in the alkaline battery of the present invention has a mercury content of 5 to 15%.
Even if it is less than 1 weight % by weight, or even less than 1 weight ω%, gas generation can be suppressed to the same degree or more than conventional products. Of course, it is also possible to increase the mercury content and increase the gas generation suppressing function accordingly. In practical terms, the preferable mercury content of the cathode active material in the present invention is 5% or less, which has a sufficiently greater suppressive effect than the conventional cathode active material made of amalgamated zinc powder.

In addition, the content of lead and indium is 0.00, respectively.
A small amount of about 5 to 1% by weight is enough to exhibit the effect of blending, and even if more is blended, the effect is small.

The alkaline battery of the present invention can be obtained by various methods, but the preferred manufacturing method is: (1) Amalgamation obtained by alloying lead, indium, and mercury, and amalgamating zinc powder using the alloy. A method for producing an alkaline battery characterized by using zinc powder as a cathode active material for a battery; This is a method for producing an alkaline battery characterized by using the method as a cathode active material.

The first manufacturing method is carried out, for example, as follows.

First, zinc powder is added to an alkaline solution such as an aqueous potassium hydroxide solution and preliminarily stirred for 1 to 30 minutes. Then,
An alloy of lead, indium, and mercury mixed in advance is gradually dropped into the above liquid through a small hole and stirred for 30 to 120 minutes, then washed with water and dried at a low temperature of 30 to 60°C. Zinc-lead-indium-mercury powder was mixed in a 1:1 ratio. Mercury has the property of forming an alloy not only with zinc but also with lead and indium at room temperature, and the alloy is contained in zinc powder while maintaining the lead, mercury or indium/mercury ratio in the alloy. . 2. Therefore, by changing the content of lead and indium in the alloy, the content of lead and indium-C*silver in the zinc powder can be freely changed.

-〇- -11 In the second manufacturing method, first, lead and indium are added to molten zinc, and the alloy powder is made into an alloy powder. By adding mercury to an alkaline solution containing indium alloy powder,
J: Obtain zinc-lead-indium-mercury powder.

By using the zinc-lead-indium-mercury powder obtained in this way as a cathode active material, gas generation ip
Provided is an alkaline battery in which the amount of energy is suppressed and which has excellent battery performance.

Hereinafter, the present invention will be broadly explained based on Examples J and Comparative Examples.

Example 1 (a) to (e) First, 0.0550 lead, 0.11 g of indium, and 4.84 CJ of mercury were mixed in a 1:3 salt bath so that the ratio of lead and indium 11 was 1.1, respectively. A lead-indium amalgam of 2.2% by weight by weight was prepared. Next, 0.5% of a 10% potassium hydroxide solution prepared in advance
35 to 100 mesh commercially available zinc powder for batteries 25
0 g and pre-stirred for 5 minutes at 20°C.

Next, amalgamation was performed by stirring at 20°C for 60 minutes while gradually dropping a predetermined amount of the 'f4i-indium\ amalgam through the coarse holes. After the amalgamation was completed, it was washed with water and dried at 45° C. for a day and a night. In this way, the content of lead, indium, and mercury was reduced to 0.01%, 0.02%, and 0.0%, respectively.
．． A 9% by weight zinc-lead-indium-mercury powder (Example 1(a)) was obtained 1'.

In addition, the ratio of lead and indium is (1) 0.65% lead, 1.3% indium, (
2) Lead 0.34% by weight, Indium 0.67% by weight, (
3) Lead 0.20%, indium 0.40φ repellent, (
4) After preparing a lead-indium amalgam containing 0.14% lead and 0.29% by weight indium, amalgamation was performed in the same manner as above to obtain a lead-containing 'P4'; 0.01% by weight.
, indium content of 0.02% by weight and mercury content of 1.5% by weight (Example 1C1))), 3% by weight (Example 11'c g>), 5% by weight (Example 1( d
)), 7% by weight (Example 1(e)) of zinc-1i)-indium-mercury powder was obtained.

A hydrogen gas generation test was conducted using the zinc-lead-indium-mercury powder thus obtained as a cathode active material. The results are shown in Table 1. In addition, the gas generation test was carried out using a potassium hydroxide aqueous solution with a concentration of 40 times as the electrolyte, saturated with zinc oxide, and 10 g of each cathode active material consisting of zinc-lead-indium-mercury powder. 45
The gas evolution rate (mg/a day) was measured at °C.

Further, the battery performance of this negative electrode active material made of zinc-lead-indium-mercury powder was evaluated using an alkaline mankan battery shown in FIG. 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 amalgamated zinc powder gelled with carboxymethyl cellulose, a negative electrode current collector 5, a rubber packing 6, and a holding plate 7. .

Using this alkaline manganese battery, the discharge load is 4Ω, 20Ω.
The intercostal discharge was measured under the discharge conditions of .degree. C. until the final voltage was 0.9 V9-, and the measured value of Comparative Example 1(d) using the conventional cathode active material described above was set as an index of 100. The results are shown in Table 2. Example 2 In the same manner as in Example 1, lead and indium 11' were prepared.

After preparing lead-indium amalgam with a content of 5.2% by weight and 2.1% by weight, amalgamation was performed to obtain a lead, indium, and mercury content of 0.05% by weight, respectively.
Zinc-lead-indium-mercury powders of 0.02% by weight and 0.9% by weight were obtained.

Using this zinc-lead-indium-mercury powder as a cathode active material, a gas generation test and a battery performance test were conducted in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

Example 3 In the same manner as in Example 1, lead and indium n-doubles were prepared at 1.1 weight % and 11. A lead-indium amalgam containing 0.0% by weight was prepared and amalgamated so that the lead, indium and mercury contents were 0.01% by weight and 0.01% by weight, respectively.
A lead-lead-indium-mercury powder of 1% by weight and 0.9% by weight was obtained.

Is this zinc-lead-indium-mercury powder a cathode active material? As Example 1, a gas generation test and a battery performance test were conducted in the same manner as in Example 1, and the results are shown in Tables 1, 13, and 2.

Example 4 A lead-indium amalgam with lead and indium ratios of 5.7% by weight and 11.0% by weight, respectively, was prepared in the same manner as in Example 1, and then amalgamated to reduce the lead, indium, and mercury contents. are respectively 0.05 weight% and 0.1
A zinc-lead-indium-mercury powder of 0.9% by weight was obtained.

Using this zinc-lead-indium-mercury powder as a cathode active material, a gas generation test and a battery performance test were conducted in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

Example 5 Lead and indium were added to molten zinc and stirred at a temperature of about 430°C until the content of lead and indium was 0.0, respectively.
A zinc-yariichi indium alloy of 5% by mass and 0.02% by weight was prepared, and this was powdered]! is.

Using mercury, this zinc-lead-indium alloy powder was subjected to a fumarame sheen using the same method as in Example 1, so that the lead, indium, and mercury content was 0.05% by weight each.
0.02? F amount %, 0, 9"': ?J'% (1
) 'If, @f)-Lead-indium-mercury powder was obtained.

Using this zinc-Iff-indium-mercury powder as a cathode active material, a scum generation test and a battery performance test were conducted in the same manner as in Example 1, and the results are shown in Tables 1 and 2.

Comparative Examples 1(a) to (e) Conventionally used mercury content: 0.9% by weight (Comparative Example 1(a)), 1.5% by weight (Comparative Example 1(1))), 3
Model car% (Comparative example 1 (c), 5% by weight (Comparative example 1 ((
1)), 7% by weight (comparative example 1 (C)) - mercury powder was used as the cathode active material, and a gas generation test and a battery performance test were conducted in the same manner as in Example 1, and the results were reported. 1st
It is shown in Table Jζ and Table 2.

1st Table 13- 2nd Table 14- As shown in Tables 1 and 2, Examples 1(a) to (e) using a cathode active material in which lead and indium coexisted.
), 2 to 4 have a higher gas generation suppressing effect than Comparative Examples 1(a) to (e) in which only mercury-zinc was used as the cathode active material, and the amount of mercury can be significantly reduced.

It is also understood that the battery performance is superior to Comparative Example 1(d) in which a mercury-zinc alloy containing 5Φ% of mercury was used as the cathode active material.

[Brief explanation of the drawing]

FIG. 1 shows a sectional view of an alkaline manganese battery according to the present invention. 1: Positive electrode can, 2: Positive electrode, 3: Separator, 4: Negative electrode made by gelling amalgamated zinc powder with carboxydimethyl cell []-su, 5: Negative electrode current collector, 6: Rubber packing, 7: Pressed λ plate 15- Figure 1 281-

Claims (1)

[Claims] 1. An alkaline battery characterized by using amalgamated zinc powder in which lead and indium coexist as a cathode active material for batteries: i! ! . 2. The alkaline battery according to claim 1, wherein the lead and indium contents of the amalgamated zinc powder are each 0.005-1% by weight. 3. The alkaline battery according to claim 1 or 2, wherein the mercury content of the Amalkamuihi pressed lead powder is 5% or less. 4. The mercury content of the amalgamated zinc powder is 1% by weight.
A soft alkaline battery according to claim 3, which is as follows. 5. A method for producing an alkaline battery, characterized in that an amalgamated zinc powder obtained by alloying lead, indium, and mercury and amalgamating zinc powder using the alloy is used as a cathode active material for a battery. 6. A method for producing an alkaline battery, characterized in that an amalgamated alloy powder obtained by amalgamating an alloy powder of zinc, lead, and indium in a water collection is used as a battery cathode active material in 17.