JPH0586624B2 - - Google Patents

Description

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

Conventional technology Conventionally, as a manufacturing method for 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, followed by 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 at each washing time, which requires a lot of man-hours, which 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 active material on the surface of a porous body influences the final amount of deposit, and At the first time of operation, it is immersed in a high concentration raw material salt solution and then immediately immersed in a low concentration raw material salt solution, followed by intermediate drying, alkali treatment, water washing, and drying, and from the second time onwards, it is immersed in a high concentration raw material salt solution. After that, the active material is filled by first performing intermediate drying, then immersing in a low concentration raw material salt solution, and repeating the steps of alkali treatment, water washing, and drying.

Function The effect of intermediate drying is to remove and fix water contained in the raw salt solution and to remove excess raw salt solution adhering to the surface of the porous body by draining. In the present invention, by performing intermediate drying after immersion in a low-concentration raw material salt solution in the first impregnation operation, the latter effect of intermediate drying can be utilized to minimize deposits on the surface of the porous body. In addition, from the second time onwards, the active material raw salt solution is concentrated and fixed by utilizing the former effect of intermediate drying, and then it is immobilized on the surface of the porous body by immersing it in a low concentration raw material salt solution. It becomes possible to selectively remove raw material salt.

Note that if you take the method of immersing in low concentration raw material salt after intermediate drying in the same way as from the first to second impregnation operations, the intermediate drying will be done in the first time when the porous body is not covered with hydroxide, which is the active material. During drying, the porosity is eroded by the oxidizing power of the oxidizing substances (e.g. NO _x ) contained in the raw salt at high temperatures, and surface deposits are likely to increase, making it difficult to adopt from the standpoint of reducing deposits. be.

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 was 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 the specific gravity
1.30, immersed in nickel nitrate solution (B) at 50°C for 30 seconds, then dried at 140°C for 10 minutes, followed by alkali treatment, washing with water, and drying. After the second impregnation operation, after immersing in nickel nitrate solution (A) under the above conditions, immediately intermediate drying, then immersion in nickel nitrate solution (B), alkaline treatment, water washing,
The active material was filled by repeating each drying process five times.

FIG. 1 shows the filling amount of the active material at each impregnation number of the electrode plate prepared by the above method and the filling amount when Conventional Method 2 was used. It can be seen that the method of the present invention can secure the active material more efficiently than the conventional method 2.
Also, the deposition on the surface was the same.

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, in the first repetition, a low concentration A method for producing an electrode plate for an alkaline storage battery, characterized in that intermediate drying is performed after immersion in a raw material salt solution and, from the second time onward, before immersion in a low concentration raw material salt solution.