JPH0586625B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing electrode plates for alkaline storage batteries, and relates to filling an active material into a nickel porous body used therein.

Conventional technology Conventionally, as a method for manufacturing electrode plates for this type of alkaline storage battery, porous nickel obtained by sintering carbonyl nickel powder or its slurry at a temperature of 700 to 1000°C in a hydrogen or nitrogen atmosphere has been used. The active material was filled by repeating the process of immersing the body in an active material raw material salt solution and then converting it into an active material in caustic alkali.

In the above-mentioned filling step, a layer of active material is deposited on the surface of the porous body, and this deposit blocks the pores of the porous body, and since these deposits are insoluble, they remain without being removed even in the next water washing process. It gradually covers the pores on the surface and prevents the raw salt solution from entering the pores.

In order to eliminate these drawbacks, a conventional method (hereinafter referred to as "conventional method 1") in which deposits on the surface are removed by brushing during washing with water in the above-mentioned filling process has been proposed.
) was adopted.

In addition, as another method, as shown in Japanese Patent Publication No. 60-8585, the porous body taken out from the impregnating liquid is immersed in an impregnating liquid of a lower concentration for several tens of seconds, and then subjected to intermediate drying. A method has been proposed in which a porous body is filled with an active material while removing deposits on the surface of the porous body by repeating the process of converting the porous body into an active material using an alkali or the like (hereinafter referred to as "conventional method 2"). There is.

Problems to be Solved by the Invention However, in the above-mentioned conventional method 1, brushing is performed each time during each washing, which takes a lot of man-hours, complicates the filling process, and damages the electrode surface. Method 2 can remove deposits, but when immersed in each low concentration solution, the concentration of the impregnating solution in the pores of the previously impregnated porous body also decreases, resulting in a decrease in the amount of impregnation. It will happen. The present invention aims to obviate these drawbacks.

Means for Solving the Problems In order to achieve the above object, the present invention has discovered that the initial deposition of an active material on the surface of a porous body influences the final amount of deposit, At the first time of repeated impregnation, after treating the porous body impregnated with a high concentration active material raw salt solution using a low concentration active material raw salt solution having a lower concentration than in subsequent impregnation operations,
It is made into an active material.

Effect By immersing the active material raw material salt solution at a lower concentration for the first time, it is possible to extremely lower the raw material salt concentration on the surface of the porous body immediately before it is made into an active material. Also 2
After the first treatment, the porous body impregnated with the high concentration active material raw salt solution is treated with a low concentration active material raw salt solution with a higher concentration than the first time, so that the raw material salt solution in the pores of the porous body is treated. Since concentration reduction can be suppressed, deposits on the surface of the porous body can be reduced while ensuring a high active material filling rate.

In addition, if the material is immersed in the low-concentration raw salt solution required for the first time deposit removal, the raw material salt impregnated into the pores of the porous body will also be removed, making it difficult to efficiently secure the active material. Become.

Example An embodiment of the present invention will be described.

A nickel sintered porous body with a length of 200 mm, a width of 33 mm, and a thickness of 0.55 mm is immersed in a nickel nitrate solution (A) with a specific gravity of 1.75 and a temperature of 80°C for 30 minutes, then taken out, and then nickel nitrate with a specific gravity of 1.20 and a temperature of 50°C. 30 to solution (B)
Immersed for seconds. Then intermediate drying, alkali treatment,
Washed with water and dried. From the second time onward, a solution with a specific gravity of 1.55 was used as the nickel nitrate solution (B), and the same impregnation operation as the first time was repeated five times to fill the active material.

FIG. 1 shows the filling amount of active material for each number of impregnations of the electrode plate prepared by the above method and the filling amount when a specific gravity of 1.30 was used as the nickel nitrate solution (B) in Conventional Method 2. It can be seen that the method of the present invention can secure the active material more efficiently than the conventional method 2.

Effects of the Invention As described above, according to the present invention, there is no damage to the surface of the electrode plate, and the amount of active material filled per impregnation operation can be efficiently ensured, making it possible to shorten the process, which has great industrial value. It is something.

[Brief explanation of the drawing]

FIG. 1 is a curve diagram showing the availability of active materials according to an embodiment of the present invention and conventional method 2.

Claims (1)

[Claims] 1 After immersing the porous body in the active material raw material salt solution,
In the step of filling a porous body with an active material by repeatedly immersing it in a raw material salt solution having a lower concentration than the raw material salt solution and then converting it into an active material, the first low concentration raw material salt solution is A method for manufacturing an electrode plate for an alkaline storage battery, which is characterized by making the electrode plate thinner than that of the subsequent electrode plate.