JPS58155655A - Manufacture of alkaline battery - Google Patents

Abstract

PURPOSE:To increase a battery life and manufacturing efficiency by cleaning the surface of copper or copper alloy, which is to be in contact with a negative mass, of a negative current collector with a chemical polishing solution of hydtogen peroxide and sulfuric acid family containing a rust preventive, and applying rust preventing treatment on the surface at the same time. CONSTITUTION:A reverse curl portion 5 of the circumference of a negative case 1 is covered with a synthetic resin jig 6. This case is treated with a chemical polishing solution that the molar ratio of sulfuric acid to hydrogen peroxide is 0.045 and about 0.2% of benzotriazole is contained as a rust preventive for about 2min at room temperature. Then the case is washed with water, washed with a solution containing sulfuric acid, washed with water, neutralized, and washed with water again. By this treatment, the exposed surface of copper is polished chemically and harmful foreign matter is removed and at the same time a rust preventing film is formed on the cleaned surface.

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.

In general, alkaline batteries are made by filling a positive electrode active material in a metal positive electrode container that also serves as a positive electrode terminal, a negative electrode active material and an alkaline electrolyte in a metal negative electrode container that also serves as a negative electrode terminal, and then inserting a separator between the two. The two containers are fitted together via an insulating gasket, 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 copper or copper alloy, or a three-layer clad plate of nickel, stainless steel, copper, or copper alloy so that the copper or copper alloy side becomes the inner surface of the container. It is.

The copper 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 steel or steel 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 steel alloy surface of the negative electrode container comes into contact with the frozen zinc of the negative electrode active material, thereby performing 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 pond can be sealed tightly.

If foreign substances such as stainless steel, nickel, etc. remain on the steel or copper alloy surface, it is difficult for these foreign substances to be hydrated and galvanized.

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 that tends to generate hydrogen gas by filling the inside of the battery with hydrogen gas after assembly, increasing the internal pressure of the battery, causing leakage, or causing the battery to explode, is a serious defect in the battery. .

This invention was made based on the above circumstances.

Hydrogen peroxide containing these rust inhibitors is applied to the surface of copper or copper alloy that comes into contact with the negative electrode active material of the negative electrode at-body.

By cleaning with a sulfuric acid-based chemical polishing liquid and applying rust prevention at the same time, less hydrogen gas is generated, so there is no leakage, increased impedance, bursting, etc., extending the service life and improving work efficiency. The purpose of this invention is to provide a method for manufacturing an alkaline battery that can be used to produce alkaline batteries.

In other words, it may be difficult to remove foreign substances such as fine metal particles attached to the steel or steel alloy of the negative electrode container using normal cleaning methods, or it may be difficult to remove these harmful foreign substances by scraping the surface of the steel or steel alloy to a certain thickness. This was solved by taking it.

The thickness to be removed by this polishing is determined by the degree of dirt and foreign matter adhering to the surface and the thickness of the copper or steel alloy. The thickness of the steel or steel alloy surface is 10 times the thickness of the entire clad plate.
If the degree of attack is standard and therefore the clad plate is thin, the steel or steel alloy layer will also be thin and the thickness that can be scraped will be limited.

When the thickness of the clad plate is 9.3 mm, the thickness of the copper or steel alloy is generally about 30 μm, and there is no risk of exposing the inner stainless steel layer even if it is scraped for about 10 seconds, but It is expensive and impractical to do so. It was confirmed that the depth of foreign matter such as stainless steel, nickel, etc. attached to or embedded in the copper or copper alloy surface of the negative electrode container is approximately 3 to 5 μm at the deepest, and that it was possible to scrape off approximately 6 μm. .

In this case, chemical polishing is suitable as a means for scraping the copper or steel alloy surface because the thickness to be scraped can be controlled relatively easily. More specifically, the use of hydrogen peroxide and sulfuric acid-based chemical abrasives has the advantage that the thickness to be scraped can be precisely controlled by selecting the composition of hydrogen peroxide and sulfuric acid, processing temperature, and time. .

If the steel or copper alloy surface is brought into contact with the steel or copper alloy surface after the foreign matter has been removed, it will take time for the steel or copper alloy surface to undergo oxidation and zinc plating, and until then, 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 frozen zinc 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, the surface is polished and cleaned using hydrogen peroxide and sulfuric acid-based chemical abrasives containing rust preventive agents for steel or copper alloy, and at the same time a rust preventive film is formed on the surface. The generation of hydrogen gas is prevented by filling with electrolyte. In this case, as a rust preventive agent,
Triazole derivatives commonly used as rust inhibitors for steel 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 steel or steel alloy in the vicinity of the folded part is stretched to a high degree of processing and other parts It is thinner than the other parts. Therefore, if this part is scraped off with a chemical polishing solution, the stainless steel scale will be 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, a three-layer Crassito board made of nickel, stainless steel 2, and copper 3 with a total thickness of 9.3 mm and a steel thickness of 30 is used, and this is drawn. A negative electrode container 4 is manufactured.

A jig 6 made of synthetic resin is attached to the peripheral folded part 5 of this negative electrode container 4.
After contacting and covering the surface, it contains about 0.21 moles of benzotriazole as a rust preventive agent, about 10 moles of hydrogen peroxide, and 0.45 moles of sulfuric acid, and the molar ratio of sulfuric acid to hydrogen peroxide is 0.045. After being treated with a chemical polishing solution for about 2 minutes at room temperature, the exposed surface of the steel 3 is chemically scraped by repeating water washing, sulfuric acid washing, water washing, neutralization, and water washing to remove foreign substances and clean it. At the same time as rubbing, a rust-preventing coating is formed on the clean surface. The average thickness of the steel surface is approximately 6μ
shall be.

is a short cylindrical cathode container with a bottom made of nickel-plated steel plate, 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, 1G
1 is an electrolyte holding material made of a porous fiber material impregnated with an alkaline electrolyte, and 11 is zinc chloride as a negative electrode active material. An insulating backing 12 insulates and seals the gap between the positive electrode container 7 and the negative electrode container 4, and the opening of the positive electrode container 1 is curved inward to fasten the backing.

In the figure, 13 is a ring.

For comparison, the interior of batteries with various treatment solution compositions, including the battery 0, made in this way, and a conventional battery assembled using the same negative electrode container that had been washed with trichlene, alkaline, washed with water, and dried. (G) was compared with respect to leakage. In other words, Table 1 is.

These batteries were placed in a test tank at a temperature of 60°C and a humidity of 90°C.
The figure shows the number of leaked samples for each 1000 samples stored using a 10x microscope.

Table 1 and Table 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°C.
This shows the number of batteries whose height has increased by mm or more.

Table 2 According to Table 1, in the case of the conventional product η, leakage starts after 20 days of storage and rapidly increases as the number of days increases, whereas in the case of the battery of the present invention (g) A small number of leaks started after 30 days of storage, and even if the number of days increased, the number of leaks was significantly smaller than in the case of the conventional product (G).

Further, according to Table 2, the number of defects in the battery according to the present invention can be suppressed to about V7 or less compared to the number of defects in the case of the conventional product η.

In addition, through @Table 1 and Table 2, hydrogen peroxide is 8 to 10 moles, sulfur # is 0.25 to 0.6 mole, and the molar ratio of sulfuric acid to hydrogen peroxide is included in the @circle of Q, 03 to 0.06. It can be seen that particularly good test results can be obtained in the case of -○.

As described above, according to the present invention, the surface of the copper or steel alloy that comes into contact with the negative electrode active material of the AII current collector is cleaned with a chemical polishing solution based on hydrogen peroxide or sulfuric acid containing these rust preventive agents. At the same time, by applying rust prevention, the generation of hydrogen gas is reduced, so there is no leakage, impedance increase, explosion, etc., and the lifespan of alkaline batteries can be extended, and work efficiency can be improved. A manufacturing method can be provided.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist. 6. Does the above example show the case where a maazole derivative is used as a rust preventive agent? Rust inhibitors are not limited to these.

[Brief explanation of drawings]

FIG. 1 is a #i, BA diagram of the manufacturing process of an embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view showing a mercury oxide battery obtained by the same embodiment. 1... Nickel 2... Stainless steel 3... Copper 4... Negative electrode container 5... Peripheral folded part 6... Jig 7... Positive electrode container
8... Anode mixture 9... Separator 1o... Electrolyte holding material 11... Zinc oxide 12... Insulating backing 13... Nectar body

Claims (4)

[Claims] (1) The surface of the steel or copper alloy that is in contact with the negative electrode active material of the negative electrode current collector is cleaned and rust-prevented by polishing it with hydrogen peroxide or sulfuric acid-based chemical polishing liquid that contains a steel or steel alloy rust inhibitor. A method for producing an alkaline battery, characterized by carrying out the following at the same time. (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 method for manufacturing an alkaline battery according to any one of claims 1 to 3, characterized in that a triazole derivative is used as the rust preventive agent.