JPS6042586B2 - Method for manufacturing sintered substrate for storage battery electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a porous sintered substrate used for electrodes such as nickel-cadmium alkaline storage batteries.

Conventionally, sintered substrates used for electrodes in nickel-cadmium alkaline storage batteries, etc., are made by applying a slurry consisting of nickel powder for sintering and an aqueous solution of a water-soluble organic adhesive such as carboxymethyl cellulose (CMC) to a strip-shaped porous metal plate. It is manufactured by coating and filling both sides, drying it with infrared rays, and then sintering it.

However, during drying, the slurry is dried from its surface, so the drying conditions are different between the surface and the inside of the slurry, and this has caused cracks to easily form on the surface of the dried slurry in conventional methods. . This tendency is particularly noticeable when the slurry is dried at high temperatures in a short period of time or when the slurry is applied thickly. For this reason, cracks will not occur in the slurry layer if the drying treatment is carried out at as low a temperature as possible for a long time, but this method reduces productivity and is not suitable for continuous industrial production. The present invention has been made in view of the above-mentioned circumstances, and its purpose is to mix carbon fibers or metal fibers into a slurry, and to dry and sinter a porous metal plate coated with this slurry. The present invention provides a method for manufacturing a sintered substrate for a storage battery electrode in which the strength of the slurry is increased with fibers and cracks do not occur on the surface of the dried slurry layer.

That is, the present invention is a method characterized by coating and filling a slurry of a mixture of nickel powder for sintering a porous metal plate, an organic adhesive aqueous solution, and carbon fiber or metal fiber, and then drying and sintering the slurry. be.

The method of the present invention will be explained in detail below.

First, carbonyl nickel powder with a density of 0.5 to 0.7 da/
cc of nickel powder for sintering 30~marked weight part and 2~4%
A mixture having the same composition as a nickel slurry prepared by a conventional method is prepared by kneading an aqueous solution of an organic adhesive such as an aqueous solution of carboxymethyl cellulose with 50 to 7 parts of the mass.

Then, metal fibers such as carbon fibers or nickel fibers are added alone or in combination to the above mixture, and the mixture is uniformly mixed to prepare a nickel slurry according to the method of the present invention.
The length of each fiber of this Yang combination is 5 to 2077!77! considering the workability when uniformly mixing these fibers. degree is preferred.
The mixing ratio is preferably within a range that has a large reinforcing effect on the dried slurry layer and does not relatively reduce the nickel content contained in the sintered layer. For example, a mixture of nickel powder and an organic adhesive aqueous solution is preferable. Approximately 10 parts by weight or less is suitable for 1 part by weight of the recess. Next, the slurry is applied to a porous metal plate and dried using infrared rays or heat rays.

In this case, the porous metal plate is a commonly used band plate such as a punched nickel-plated band iron plate or a band-shaped nickel lath sheet. When a porous metal plate coated with slurry is dried in this way, the drying progresses from the surface, and stress is applied to the surface of the slurry layer in the direction of tearing it, but the slurry layer contains fibers in a tangled state. Therefore, each fiber receives this stress and no cracks occur on the surface. Particularly when drying at a high temperature of about 160 to 180°C in a short time of about 5 to 1 powder, or 1.
Even in cases where cracks are likely to occur, such as when drying a slurry layer as thick as 0 to 1.4 mm, the slurry layer can be dried satisfactorily. Then, the porous metal plate with the slurry layer dried is sintered at 850 to 950°C in a reducing atmosphere such as hydrogen gas or ammonia decomposition gas to produce a sintered substrate.

In this case, the fibers, the metal powder for sintering, and the porous metal plate are bound together to prevent cracks in the sintered layer and to increase the mechanical strength of the sintered substrate. Moreover, its conductivity is maintained well.
Next, examples of the method of the present invention will be described.

Carbonyl nickel powder with a density of 0.5 to 0.7 q/Cc was used as the nickel powder for sintering, and a 3% carboxymethyl cellulose aqueous solution was used as the organic adhesive aqueous solution. part was added and kneaded.

Next, nickel fibers having a length of about 10 WL were uniformly mixed into this kneaded material at a ratio of 0.05 parts by weight per 10 parts of the kneaded material to prepare a nickel slurry. 177!77 on both sides of a 0.1w0n thick strip nickel plate punched with this slurry! After coating and filling it to a thickness of 1,000 yen, it was irradiated with infrared rays and dried at 160 to 180° C. for 5 minutes. As a result of observing the dried slurry, no cracks were observed on its surface. The porous metal plate on which the dried slurry layer was formed was sintered in an ammonia decomposition gas atmosphere at 850 to 950°C to form a layer with a thickness of 1.3wn1.
A sintered substrate with a porosity of 80% was obtained. On the other hand, when a conventional nickel slurry containing no fibers was applied to a porous metal plate in the same manner as in the above example, and then dried and sintered, many cracks were generated.

In addition, the sintered substrates obtained in this way were impregnated with nickel active material and cadmium active material to produce negative and anode plates, and the battery characteristics of the alkaline storage battery obtained by assembling the plates with these plates were investigated. However, there was no difference between the method of the present invention and the conventional method.

As is clear from the above results, according to the method of the present invention, the mechanical strength of the sintered substrate can be increased because carbon fibers or metal fibers are mixed in the slurry and applied to the porous metal plate. Even when drying a slurry layer at high temperature in a short time, or when drying a thick slurry layer, cracks do not occur on the surface, and the drying conditions are different between the surface and the inside. Since cracks do not occur even when sintered, good sintered substrates can be mass-produced in a short period of time, and other remarkable effects are achieved.

Claims (1)

[Claims] 1. A sintered substrate for a storage battery electrode, which is characterized in that a porous metal plate is coated with a slurry of a mixture of nickel powder for sintering, an aqueous organic adhesive solution, and carbon fibers or metal fibers, and then dried and sintered. Production method.