JPS5832460B2 - Sealed battery manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a sealed battery, and an object of the present invention is to provide a sealed battery with excellent leakage resistance.

Conventionally, sealed batteries using alkaline electrolytes, such as silver oxide batteries, nickel-zinc batteries, manganese-zinc batteries, etc.
Although the battery characteristics are excellent, the problem is that the alkaline electrolyte tends to leak out to the outer negative electrode terminal surface due to electrochemical capillary action on the negative electrode terminal side, which is the so-called creep property.

This is because the alkaline electrolyte enters the extremely small gap that exists between the metal sealing plate and the sealing backing, and eventually leaks out to the negative electrode terminal surface on the outside, and the alkali that leaks out is absorbed into the air. When contacted with carbon dioxide gas and other active gases, alkali metal salts such as alkali carbonates are produced.

Therefore, this product inhibits electrical continuity between the negative electrode terminal surface and the terminal contact surface of the device used.

In order to prevent these problems, conventional efforts have been made to completely eliminate the minute gap between the sealing backing and the metal sealing plate.

For example, a method in which a sealing backing material is crimped onto the periphery of a metal sealing plate using a so-called mold forming method to integrate it;
Alternatively, a method has been adopted in which a liquid backing such as polyisobutylene or an adhesive is interposed on the contact surface between the metal sealing plate and the sealing backing to fill the gap between the two.

However, when molding the backing, the metal sealing plate is firmly fixed with a mold, so many scratches may occur on the inner and outer surfaces of the metal sealing plate, and the mold material may be damaged due to the strong molding pressure. The metal sealing plate remains in a shape other than the initial design shape, the yield is extremely poor, and the sealing pressure when sealing the battery case causes misalignment between the metal sealing plate and the sealing backing, resulting in alkaline electrolysis. It was not possible to completely fill the minute gaps in the creep path of the liquid.

In addition, when using a liquid gasket, as long as it does not affect the strong alkali resistance of the liquid backing, a metal sealing plate
If it is interposed between the metal sealing plate and the sealing backing, the molecular film of the liquid backing will cover the fine gaps between both sides, and the gap can be sufficiently sealed. The liquid backing discharged by the sealing pressure sometimes adheres to the battery, requiring post-processing such as its removal, which is inconvenient when assembling the battery.

Furthermore, during storage, the liquid backing leaks to the outside due to an increase in the internal pressure within the battery, resulting in a poor contact before the battery is used, which tends to cause inconvenience during use.

Furthermore, if the gap filler is an adhesive, the application of the adhesive becomes meaningless because the pressure at the time of sealing causes displacement at the adhesive interface as described above.

The present invention provides a method for manufacturing a sealed battery that solves the above-mentioned problems with liquid backing. After applying the electrolyte-based liquid backing,
A metal sealing plate is fitted into this sealing backing, and then a sealing member is used in which the space between the peripheral edge of the sealing plate and the inner surface of the sealing backing is filled with a dry solidified filler capable of forming a film. Features.

Embodiments of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is a metal case made of stainless steel or iron with nickel plating, chromium plating, or alloy plating of these.The inner bottom of the case is coated with silver oxide, which is a positive electrode active material, and graphite, which is a conduction aid. The positive electrode mixture 2, which is a mixture of the following, is integrated under pressure.

Therefore, the metal case 1 also serves as a positive terminal.

3 is an isolation layer for preventing internal short circuit between the positive electrode mixture 2 and the negative electrode active material 4, and is a plastic film in which micropores of several sizes are formed by radiation, laser beam irradiation, corona discharge method, etc. be.

The metal sealing plate 5 contains therein the alkaline electrolyte and the zinc chloride powder which is the negative electrode active material 4, and thus also serves as a negative electrode terminal.

Reference numeral 6 denotes an insulating sealing backing attached to the periphery of the metal sealing plate 5, which is made of engineering plastics such as nylon, polyacetal, polypropylene, etc., or a combination of these, and serves as insulation between the negative electrode and the positive electrode, as well as internal electrolyte. This prevents leakage of water to the outside.

7 is a liquid backing injected into the inner bottom 6a of the sealing backing 6, which contains cis-1,4 polyisoprene, 1,2 polybutadiene, cis-1,4 polybutadiene, butadiene-styrene copolymer, It consists of liquid rubber such as ethylene-propylene copolymer, polysulfide synthetic rubber, and polyisobutylene, or liquid synthetic resin such as unopened epoxy resin and liquid nylon, all of which are viscoelastic substances that are permanently non-drying. , act as a flow resistance for leaking electrolyte, and are all pure organic substances.
It does not affect the electromotive reaction of the battery.

8 is a dry solidified liquid filled in the space 6b formed by the sealing backing 6 and the peripheral portion of the metal sealing plate 5 after the liquid backing 7 is injected and the subsequent sealing plate 5 is fitted. It is a filler.

Examples of this are asphalt pitch, asphalt pitch with microcrystalline wax, metal soap, polyflon grease, etc., two-component epoxy resin adhesive of ring-opened epoxy resin and fatty acid amine, and polyamide resin. and polycarbonate resins, synthetic resin adhesives such as Fehr resin and phenoxy resin, and synthetic rubbers such as high molecular weight, high degree of polymerization polyisobutylene and chlorosulfonated polyethylene.

Further, as a method of injecting and filling these substances, it is sufficient to dissolve and dilute each substance with a solvent having similar SP parameters and inject it.

Next, in order to investigate the effect of the battery manufactured by the method of the present invention,
500 JIS product number G13 silver-zinc oxide sealed alkaline batteries each were stored in an atmosphere with an ambient temperature of 45°C and a relative humidity of 80-90%, and batteries leaked during storage. The cumulative frequency is shown in the table below.

A in the table uses a sealing member obtained by the method of the present invention, and is used as a liquid backing with an average molecular weight of 700 to 15.
00 polyisobutylene with blown asphalt with a penetration of 100 or less interposed as a dry solidifying filler, B uses chlorosulfonated polyethylene as a filler using the same liquid gasket as A, C 1 uses non-drying aliphatic polysulfate as a liquid backing and a polyamide based on dimer acid, such as persamide, as a filler; D uses only a liquid backing made of polyisobutylene; Similar to the above, non-drying aliphatic polysulfide is used as the liquid backing, and F indicates that no coating is applied.

The amount of liquid backing applied in D and E is the same as in A-B-C above in order to prevent scattering onto the negative terminal plate due to the pressure force during sealing and oozing due to internal pressure increase during storage. 15 compared to the amount of liquid backing applied
~b As is clear from this table, in order to increase the flow resistance of the alkaline electrolyte, the product according to the present invention has the ability to form a strong molecular film of the liquid backing to improve the fine irregularities on the surface of the metal sealing plate and the sealing backing. By coating the parts, it is possible to completely eliminate the creep gap of the electrolyte, and it is also possible to prevent the liquid backing from scattering to the outside due to the increase in internal pressure of the battery and the stress at the time of sealing. This can be prevented with a filler coating.

Therefore, it becomes possible to apply a necessary and sufficient amount of liquid backing.

In addition, even if a part of the filler coating were to protrude into the negative electrode terminal due to sealing, it would not be possible to prevent
All you have to do is scrape it off with a brush or cloth, and it is extremely suitable for mass production and can improve the leakage resistance of batteries, making it an industrially valuable product.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a sealed silver oxide battery obtained by the manufacturing method of the present invention, and FIG. 2 is a side sectional view of the main part showing the structure of the same sealing plate member. 1...Metal case, 2...Positive electrode mixture,
4... Negative electrode active material, 5... Sealing plate that also serves as negative electrode terminal, 6... Sealing backing, 7...
...Liquid backing, 8...Dry solidification type filler.

Claims (1)

[Claims] 1. After applying a non-drying, electrolyte-resistant liquid backing to the inner surface of the insulating sealing backing, which has an abbreviated cross-sectional shape, fit the peripheral part of the sealing plate that also serves as a negative electrode terminal into this part, and then A sealed battery characterized in that a battery case is sealed using a sealing member formed by filling a dry solidified filler into a space formed between a peripheral edge of a sealing plate and an inner surface of a sealing backing. manufacturing method.