JPS58155657A - Manufacture of alkaline battery - Google Patents

Abstract

PURPOSE:To reduce evolution of hydrogen gas, prevent electrolyte leakage, increase of impedance, rupture, and increase a battery life by cleaning the surface of copper or copper alloy, which is to be in contact with a negative active mass, of a negative current collector with a chemical polishing solution of hydrogen peroxide and sulfuric acid family, and then applying rust preventing treatment with a solution containing a rust preventive. CONSTITUTION:A reverse curl portion 5 of the circumference of a negative case 4 is covered with a synthetic resin jig 6. This case is treated with a chemical polishing solution containing 10mol of hydrogen peroxide and about 0.45mol of sulfuric acid for about 2min at room temperature. Then this case is washed with water, washed with a solution containing sulfuric acid, washed with water, nutralized, and washed with water again. By this treatment, the exposed surface of copper is polished chemically, and harmful foreign matter is removed. This cleaned case is immersed immediately in a solution containing 0.1% of benzotriazole as a rust preventive for about 15sec at 80 deg.C to form a rust preventing film, then the jig 6 is removed and the case 4 is dried.

Description

Detailed Description of the Invention This invention uses silver oxide, manganese dioxide, etc. as a positive electrode active material.
The present invention relates to a method for manufacturing an alkaline battery using zinc or the like as a negative electrode active material and an alkaline electrolyte.

Generally, in an alkaline battery, a positive electrode active material is filled in a metal positive electrode container that also serves as a positive electrode terminal, a negative electrode active material ring and an alkaline electrolyte are filled in a metal negative electrode container that also serves as a negative electrode terminal, and then a separator is interposed between the two. The two containers are fitted together via an insulating gasket consisting of the following, and the opening of the positive electrode container is bent inward to form a hermetically sealed opening.

For example, in the case of button-type silver oxide batteries, the negative electrode container is generally
Manufactured by drawing a two-layer clad plate of stainless steel and steel or steel alloy, or a three-layer clad plate of nickel, stainless steel, steel, or copper alloy so that the copper or steel alloy side becomes the inner surface of the container. It is.

The steel or steel alloy surface of the negative electrode container manufactured in this way is subjected to the clad plate manufacturing process and slit processing.

In processes such as punching and drawing, it is impossible to avoid the formation of oxides, the adhesion of dirt and dust, and the adhesion of minute pieces of metal such as stainless steel and nickel. Before battery assembly, pretreatment such as degreasing and cleaning is performed, but if these foreign substances get into scratches on the copper or copper alloy surface, or if they are pressed after adhesion, they cannot be completely removed by normal cleaning or other means. It is difficult to do so.

Due to the presence of an alkaline electrolyte, the copper or copper alloy surface of the negative electrode container comes into contact with the frozen zinc of the negative electrode active material to undergo amalgamation and galvanization.

Therefore, even though steel or copper alloy is more dangerous than zinc, hydrogen gas generation is suppressed even if it comes into contact with zinc, so the battery can be sealed.

However, if foreign substances such as stainless steel or nickel remain on the copper or copper alloy surface, it is difficult for these foreign substances to freeze and galvanize.

It remains exposed. Since these metals have a small hydrogen overvoltage, they generate hydrogen gas when the negative electrode container is filled with an alkaline solution and zinc.

Therefore, a structure in which hydrogen gas easily fills inside the battery after one assembly is a serious defect as a battery.

This invention was made based on the above circumstances.

After cleaning the steel or copper alloy that comes into contact with the negative electrode active material of the negative electrode current collector with a hydrogen peroxide or sulfuric acid-based chemical polishing solution, it is rust-prevented with an aqueous solution containing a steel or steel alloy rust inhibitor. Depending on the level of processing.

It is an object of the present invention to provide a method for manufacturing an alkaline battery that generates less hydrogen gas and therefore has a longer life without leakage, increased impedance, bursting, etc.

In other words, since it is difficult to remove foreign substances such as minute pieces of metal attached to the steel or steel alloy of the negative electrode container using normal cleaning methods, these harmful foreign substances are scraped off to a certain thickness on the surface of the steel or copper alloy. The problem was solved by this.

The standard thickness to be removed by this polishing is about 10% of the total thickness of the dirt or foreign plate on one side. Therefore, if the clad plate is thin, the steel or steel alloy layer will also be thinner and should be removed. Thickness is also limited.

When the thickness of the cladding plate is Q, 3mm, the thickness of the steel or steel alloy is generally about 30μ, and there is no risk of exposing the inner stainless steel layer even if it is scraped off by about 10 sides, but It is expensive and impractical to take. It has been confirmed that the depth at which foreign matter such as stainless steel, nickel, etc. is attached to or embedded in the steel or steel alloy surface of the negative electrode container is about 3 to 5 degrees deep, and that it is possible to scrape off about 6 μm. Ta.

In this case, chemical polishing is suitable as a means for scraping the copper or steel alloy surface, since the thickness of the scraping can be controlled relatively easily. More specifically, the power of using hydrogen peroxide, sulfuric acid-based chemical abrasives? By selecting the composition of hydrogen peroxide and sulfuric acid, treatment temperature and time, the thickness of the process can be precisely controlled.

If the copper or steel alloy surface is brought into contact with the surface after foreign matter has been removed, it will take time for the oxidation and galvanization to take place, and hydrogen gas will be generated from the steel or steel alloy surface. . Since the battery is assembled immediately after filling the negative electrode container with zinc chloride and alkaline electrolyte, hydrogen gas generation continues until after the battery is assembled. When hydrogen gas is generated inside the battery, it increases its impedance or causes leakage due to an increase in internal pressure.

Therefore, in this invention, after polishing and cleaning with a chemical abrasive, this clean surface is subjected to rust prevention treatment with an aqueous solution containing a steel or copper alloy rust preventive agent to form a rust preventive film, and then zinc hydrate The generation of hydrogen gas is prevented by filling the tank with alkaline electrolyte. In this case, as a rust inhibitor.

Triazole derivatives commonly used as rust inhibitors for copper or steel alloys can be used.

In addition, the negative electrode container is generally shaped with a folded part around the periphery by drawing processing, and when forming this folded part, the copper or steel alloy around the folded part is stretched to a high degree of processing, and other parts are It is thinner than the other parts. Therefore, if this part is scraped with a chemical polishing solution, the stainless steel may become exposed, which may generate hydrogen gas.

However, in this invention, since chemical polishing is performed while avoiding the folded portion, consideration is given to prevention of hydrogen gas generation in this respect as well.

Next, an embodiment of the present invention will be described with reference to the drawings.

As shown in Figure 1, the steel I
l, 6 (30μ nickel 1. stainless steel 2)
, @3 is used and drawn to produce the negative electrode container 4.

A jig 6 made of synthetic resin is attached to the peripheral folded part 5 of this negative electrode container 4.
After contacting the steel 3 to cover the surface, the exposed surface of the steel 3 is chemically scraped off by repeating hydrogen peroxide neutralization and water washing.
Remove foreign objects and clean.

The cleaned surface was then immersed in an aqueous solution containing 0.1% benzotriazole as a rust preventive agent and treated at 80°C for about 15 seconds to form a rust preventive film, after which the jig 6 was removed and washed with water and dried. The thickness of the steel surface to be scraped is approximately 6 tones on average.

8 is an anode mixture formed by adding graphite as a conductive agent to a silver oxide active material, 9 is an ion-permeable separator, and 10 is an electrolyte holder made of a porous fiber material impregnated with an alkaline electrolyte. Material 11 is frozen zinc as a negative electrode active material. Reference numeral 12 denotes an insulating backing that insulates the space between the positive electrode container 7 and the negative electrode container 4 and seals the gap therebetween, and the opening of the positive electrode container 1 is curved inward to fasten the backing.

13 in the figure is the body.

The battery 0 produced in this way was compared with a conventional battery η assembled using only various treatments in terms of leakage. That is, Table 1 shows the number of cells that leaked out of each 1000 cells stored in a test tank at a temperature of 60.degree. C. and a humidity of 90 minutes using a 10x microscope.

Tables 1 and 2 show changes in height due to hydrogen gas generation, etc. of batteries stored for 3 months at a temperature of 45°C and humidity of 90%, and swelled to 0.0% among 1,000 test batteries. This figure shows the number of batteries whose height is 5 mm or more.

According to Table 1, in the case of the conventional product Moe, leakage begins after 20 days of storage and rapidly increases as the number of days increases, whereas in the case of the battery cell battery according to the present invention, The leakage of a small number of liquids started after 30 days of storage, and even if the number of days increased, the number of liquids leaking was significantly smaller than in the case of the conventional product η.

Also, according to Table 2, compared to the number of defects in the case of the conventional product (G), the number of defects in the case of batteries 4 to (6) according to the present invention is about 1.
/9 or less.

In addition, through Table 1 and @Table 2, hydrogen peroxide 8 to 10
mol, sulfuric acid 0.25 to 0.6 mol, the molar ratio of monosulfuric acid to hydrogen peroxide is in the range of 0.03 to 0.06 (
It can be seen that particularly good test results can be obtained in the case of c) ~0.

Chemical polishing may be carried out at around 50'C depending on the case, but in the case of the above range, the processing work is carried out at room temperature (20 to 30°C).
0° C.) is sufficient, and it not only has the advantage of energy saving, but also has the advantage that the processing speed is quick and a uniform surface can be obtained.

When the thus cleaned surface is treated at 60 to 90C in an aqueous solution containing 0.5 to 0.31 of a copper or steel alloy rust preventive agent, a strong and stable rust preventive film can be obtained.

As described above, according to the present invention, after polishing and cleaning the steel or steel alloy that comes into contact with the negative electrode active material of the negative electrode current collector with a hydrogen peroxide or sulfuric acid based chemical polishing liquid, the copper or steel alloy It is an object of the present invention to provide a method for producing an alkaline battery that can prolong its life without causing leakage, impedance increase, rupture, etc., by applying rust prevention treatment with an aqueous solution containing a rust preventive agent. can.

It should be noted that the present invention is not limited to the above embodiments, and various modifications may be made without changing the gist thereof, but the rust preventive agent is not limited to these.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the manufacturing process of one embodiment of the present invention;
The figure is a longitudinal cross-sectional view showing a mercury oxide battery obtained in the same example. 1...Nickel 2...Stainless steel 3...Steel 4...Negative electrode container 5...Peripheral folded part 6...Jig 9...Separator 1
0... Electrolyte holding agent 11... Zinc hydrate 12.
-・Insulating backing 13... Ring body vE1 Figure 2

Claims (5)

[Claims] (1) After polishing and cleaning the surface of the steel or copper alloy that is in contact with the negative electrode active material of the negative electrode current collector with a hydrogen peroxide or sulfuric acid-based chemical polishing liquid, a rust preventive agent for the steel or steel alloy is added. A method for producing an alkaline battery, comprising the step of applying rust prevention treatment using an aqueous solution. (2) The method for manufacturing an alkaline battery according to claim 1, wherein the chemical polishing liquid contains 8 to 10 moles of hydrogen peroxide and 0.25 to 0.6 moles of sulfuric acid. (3) The method for manufacturing an alkaline battery according to claim 2, wherein the chemical polishing liquid has a molar ratio of sulfuric acid to hydrogen peroxide in a range of 0.03 to 0.06. (4) The above rust preventive treatment is a rust preventive agent for steel or steel alloys with 0.05
The method for producing an alkaline battery according to any one of claims ta1 to 3, characterized in that the process is carried out in an aqueous solution containing 0.301 to 60 to 90°C. (5) The method for manufacturing an alkaline battery according to any one of claims 1 to 4, characterized in that a triazole derivative is used as the rust preventive agent.