JPS6178057A - Method for manufacturing alkaline battery - Google Patents

Abstract

PURPOSE:To prevent uneven charging amount of negative pole mixture by mixing zinc powder, anti-alkaline gelatinizing agent and soluble surface active agent and filling into a battery vessel and by injecting alkali electrolyte to form the negative pole mixture. CONSTITUTION:Zinc powder or zinc alloy powder, gelatinizing agent as polyacryal acid soda and soluble surface active agent of alkali metal salt such as di-n-octyl sulfosaxinate are mixed and filled into a sealing plate 7, and alkali electrolyte is injected to form gel type negative pole mixture 6. And it is com bined with positive pole mixture 2 containing manganese dioxide mainly, a separator 3 and a nonwoven fabric 4 to form an alkaline battery. Then, wetness of gelatinizing agent and alkali electrolyte is improved by surface active agent, and uniform negative pole mixture 6 can be obtained in a short time. And uneven filling amount is prevented to improve battery performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing an alkaline battery, and more particularly to a method for manufacturing an alkaline battery with excellent heavy load discharge characteristics.

[Technical background of the invention and its problems]

Alkaline batteries are generally manufactured as follows. This will be explained using a button-type alkaline battery having the structure shown in the figure as an example.

1 is an outer can that also serves as a positive terminal, and is usually made of iron plated with 2YK. At the bottom of the outer can 1, a molded mixture 2 formed by shaping a positive electrode active material such as silver oxide or manganese dioxide into a predetermined shape is housed in close contact with the inner wall of the outer can 1. Next, on the upper surface of the molded body 2, a separator 3 with a thickness of about 0.1 mm, which is made by laminating cellophane on both sides of a microporous polyethylene sheet, is placed. A nonwoven fabric 4 is provided.

A ring-shaped insulating backing 5 is placed on top of the nonwoven fabric 4,
A sealing plate 7 that also serves as a cathode terminal filled with a negative electrode mixture 6 to be described later.
is capped, and finally the opening edge of the outer can 1 is bent inward and the whole is tightened.

In the manufacturing process as described above, the negative electrode mixture 6 used and its filling into the battery have conventionally taken the following manner.

That is, a gelled negative electrode mixture t-1i1[L,
A predetermined amount necessary for filling was weighed out of this gelled negative electrode mixture and filled into the battery.

However, with this filling method, it is difficult to accurately weigh the required gelled negative electrode mixture, resulting in large variations in the filling amount.

This makes it inevitable that the electric capacities of the cathode and anode must be well balanced in view of the demands for stabilizing battery quality and unifying standards. However, for batteries with small internal volumes such as button-type alkaline batteries, setting a large capacitance balance is one of the factors that prevents high capacitance. In addition, variations in the filling amount of the negative electrode mixture lead to variations in the electric capacity of the battery itself.
This leads to non-uniform discharge characteristics.

For this reason, recently, zinc or zinc alloy powder and a gelling agent such as sodium polyacrylate are mixed in a dry state, a predetermined amount of this dry mixed powder is weighed, and the mixture is first poured into a battery. The method used is to fill the container, and then inject an alkaline electrolyte into the container to gel the whole.

However, in this method, the surface activity of the gelling agent is low, so when the alkaline electrolyte is injected, the two do not mix well, and the gelling agent forms minute droplets surrounding the electrolyte, resulting in a uniform electrolyte. Phenomena in which it takes a long time for the gelling agent to be dispersed or the gelling agent is scattered frequently occur, resulting in an unnecessary increase in the number of man-hours in the battery assembly process. In addition, since the gelling agent is not uniformly dispersed and a homogeneous gelled negative electrode mixture is not formed, the discharge characteristics of the resulting battery deteriorate, particularly due to heavy loads and storage characteristics. are doing.

[Purpose of the invention]

The present invention solves the above-mentioned problems in an alkaline battery using a gel negative electrode mixture, improves workability during assembly, and
The purpose of the present invention is to provide a method for manufacturing an alkaline battery that has improved heavy load discharge characteristics, a large initial electric capacity, and a long shelf life.

[Summary of the invention]

The method for manufacturing an alkaline battery of the present invention includes mixing zinc powder or zinc alloy powder, an alkali-resistant gelling agent, and a water-soluble surfactant, and filling the resulting mixed powder into a predetermined portion of a battery container. The method is characterized in that an alkaline electrolyte is then injected therein.

The technical concept of the method of the present invention is based on improving the wetting between the gelling agent and the alkaline electrolyte using a water-soluble surfactant, thereby solving the above-mentioned problems.

First, the zinc powder or zinc alloy powder may be one that has been conventionally used as a negative electrode for alkaline batteries, and is not particularly limited. As a zinc alloy, frozen zinc is treated with a specified amount of mercury.

Zinc alloys containing 0.01 to 1.0% by weight of lead, indium, gallium, etc. are preferred. These powders are typically used in 40 to 250 mesh (Tyler III).

As the alkali-resistant gelling agent, conventionally used ones such as sodium polyacrylate may be used.

The blending amount of the gelling agent is usually within 5% by weight, preferably 0.2 to 2% by weight, based on the total weight of the obtained negative mold mixture.

Next, 1. The water-soluble surfactant may be omitted as long as it improves the wetting between the gelling agent and the alkaline electrolyte, but its effect is exhibited even when used in small amounts. Preferably, one or more of an alkali metal salt of di-n-octyl sulfosuccinate and an alkali metal salt of dinonylnaphthalene sulfonate are used.

Alkali metals in these salts include sodium, potassium, lithium, cesium, etc.
Particularly suitable are sodium and potassium.

Each of these salts may be used alone, or 2s or more may be used in combination as appropriate. The blending amount may be 0.02 to 0.5% by weight based on the total weight of the obtained negative electrode mixture.

If too much is used, it will foam during mixing.

In the method of the present invention, first, the above three components are mixed.

The order of mixing is not particularly limited, but dry zinc powder or zinc alloy powder and gelling agent powder are mixed, a predetermined amount of water-soluble surfactant is added thereto, and the mixture is further mixed. This method is preferable.

After weighing a predetermined amount of the mixed powder thus obtained, it is filled into the negative electrode mixture storage location already shown in the figure.

Prior to this filling operation, the mixed powder was heated at a relative humidity of 56°C.
~95cm KU4 For example, 1~2 pieces in a humidified chamber.
Leave it for 4 hours to moisten the gelling agent, then add 1
It is preferable to dry the entire product while loosening it. When this kind of treatment is applied, the gelling agent and surfactant in the mixed powder become mutually homogeneous and stable, improving the fluidity of the mixed powder, which is useful because it reduces the measurement variation during the weighing operation during filling. It is.

After filling the battery with the mixed powder, a predetermined amount of alkaline electrolyte is poured into it. Due to the action of the water-soluble surfactant, which is already homogeneous, the gelling agent is dispersed without scattering, and the electrolyte is smoothly wetted with the mixed powder in a short time, forming a homogeneous gel-like negative electrode mixture as a whole. .

Finally, the positive electrode active material is fitted to the battery outer case 1 which is tightly attached to the inner wall via the separator 3, the non-woven fabric 4 and the insulating backing 5, and a sealing plate is attached on top of this and the whole is tightened. Batteries are manufactured.

[Implementation sequence of the invention]

Implementation fill ~ 4 (1) Production of battery Particle size: 10% by weight of 48-100 mesh (Tyler sieve)
2 f of sodium polyacrylate was added to 98 g of zinc chloride powder, and the two were mixed. Then, the surfactant shown here was added in the proportion shown in the table, and the whole was thoroughly mixed. The obtained mixed powder was left in a constant humidity tank adjusted to a relative humidity of 70 degrees for 15 hours, and then loosened and dried at 30 to 60°C.

A predetermined amount (for one battery) of the mixed powder was weighed and filled into the sealing plate of the button-type silver oxide alkaline battery shown in the figure, and a 26% by weight caustic soda electrolyte in which zinc oxide was dissolved was poured into the sealing plate. . No phenomena such as powder scattering or droplet formation were observed.

Finally, the entire battery together with the outer battery case 1 was tightened to produce a button-type silver oxide alkaline battery 5R626SW. For comparison, a battery of the same type was manufactured in the same manner as in the experimental series, except that no trap surfactant was used.

(2) Performance The following items were measured. In other words, the filling amount and its dispersion when filling the battery with the mixed powder, ■ 2 of each ta
Discharge duration until 1°2V in 30KQ constant resistance discharge at 0℃, 0Discharge duration after storing each battery at 60℃ for the indicated period, 0Depth of discharge O%, 40%, 80
%, each battery was left at -10℃ for 2 hours, and then discharged for 5 seconds under the same temperature with a load of 2KQ.
This is the closed circuit voltage after seconds.

The above results are summarized in the table. In addition, in the table, the value is the average value of 100 weighings and the variation, and (B) is the average value of 100 weighings.
(C5 is a relative value when the discharge duration of each battery before storage is set as 100, ■ represents the average value of 20 batteries.

〔Effect of the invention〕

As is clear from the above results, according to the method of the present invention,
The negative electrode mixture can be made into a homogeneous gel in a short time, and the variation in the amount filled into the battery can be reduced, resulting in excellent discharge characteristics under heavy loads, a stable and long discharge duration, and a long storage life. R4! Alkaline batteries with good properties can be efficiently produced. Additionally, when filling batteries with the negative electrode mixture, phenomena such as scattering and droplet formation of the gelling agent are eliminated, resulting in reduced man-hours and improved workability in the battery assembly process, resulting in improved productivity. It is a great contribution.

[Brief explanation of drawings]

The figure is a sectional view of a button-type alkaline battery shown for explaining the method of the present invention. 1...Battery outer can 2...Positive electrode mixture 3...Separator 4...Nonwoven fabric 5...Insulating backing 6...Gel-like negative electrode mixture 7...Sealing plate

Claims (1)

[Claims] 1. Mix zinc powder or zinc alloy powder, an alkali-resistant gelling agent, and a water-soluble surfactant, fill the resulting mixed powder into a predetermined location of a battery container, and then fill it there. A method for producing an alkaline battery, which comprises injecting an alkaline electrolyte into the battery. 2. The water-soluble surfactant according to claim 1, wherein the water-soluble surfactant is at least one selected from the group of alkali metal salts of di-n-octylsulfosuccinate and alkali metal salts of dinonylnaphthalenesulfonate. Method. 3. The zinc alloy powder contains mercury, gallium, indium,
The method according to claim 1, which is a powder of a zinc alloy containing at least one member selected from the group of lead. 4. The method according to claim 1, wherein the mixed powder is moistened in a humidity chamber, then loosened and dried, and then filled into a predetermined location of a battery container.