JPH0546663B2 - - Google Patents

Description

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

Conventional technology Conventionally, as a method for producing electrode plates for this type of alkaline storage battery, a nickel porous body 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 active material in a raw material salt solution and then turning it into an active material in caustic alkali.

In the above filling process, an active material layer 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 unremoved even in the next water washing process, and gradually It covers the pores on the surface and prevents the raw salt solution from entering the pores.

In order to eliminate these drawbacks, a method (hereinafter referred to as "conventional method 1") has been adopted in which deposits on the surface are removed by brushing during washing with water in the above-mentioned filling process. Also, as another method,
As described in Japanese Patent Publication No. 39-14323, the porous body taken out from the impregnating solution is immediately immersed in water or running water for 1 to 2 seconds, and deposits on the substrate surface are removed by this instantaneous immersion in water. A method (hereinafter referred to as "conventional method 2") has been proposed.

Problems to be Solved by the Invention However, in the above-mentioned conventional method 1, since brushing is performed each time during each washing, the filling process is complicated, and the electrolytic surface is damaged. Although method 2 is effective in removing deposits, it is difficult to keep the immersion time instantaneously uniform (1 to 2 seconds) in actual production, and it also causes variations.

Means for Solving the Problems In view of the above-mentioned points, the present invention provides, in the second and subsequent impregnation operations, a porous body is immersed in an active material raw material salt solution for a long period of time, and then washed with water or under running water. The active material is filled by removing possible active material raw material salts and converting them into active materials.

Effect: The distribution of the active material in the thickness direction, which tends to be high near the surface, can be made uniform.

Example A nickel sintered porous body with a length of 250 mm, a width of 33 mm, and a thickness of 0.55 mm was immersed in a cadmium nitrate solution with a specific gravity of 2.0 and a temperature of 60°C for 15 minutes, and then taken out.
℃, immersed in 20% NaOH solution, further washed with water and dried. The electrode plate was then further heated to a specific gravity of 2.0 and a temperature of 60
After 60 minutes of immersion in a cadmium nitrate solution at 0.degree.

The filling amount of the active material for each number of impregnations of the electrode plate produced by the above method is shown in the drawing. As is clear from the drawings, it can be seen that the method of the present invention can ensure a higher amount of active material than Conventional Method 1.

After the second impregnation operation, when the porous body is immersed in the active material raw material salt for a long time, the active material consisting of the raw material salt and the hydroxide fixed in the previous impregnation operation undergoes the following reaction.
MX ₂ +M(OH) ₂ →M(OH)X transforms into an intermediate with low fluidity that does not flow out when washed with water. Since the active material can be immobilized by utilizing the above reaction, by washing away the active material raw material salt that did not participate in the reaction after immersion, it is possible to remove the active material in the thickness direction, which tends to be high near the surface in the conventional method. Distribution can be made uniform.

Note that if you wash with water for a long time after the first impregnation, all the impregnated active material raw material salt will flow out.
It becomes difficult to secure active materials. Furthermore, surface adhesion can be suppressed to 1/5 to 1/10 of that of conventional method 1.

Effects of the Invention As described above, the present invention has great industrial value, such as not damaging the electrode plate surface and ensuring a high active material filling amount.

[Brief explanation of the drawing]

The drawing is a curve diagram showing the securing of active material according to Conventional Method 1 according to an embodiment of the present invention.

Claims (1)

[Claims] 1 In the step of filling an active material by repeating immersing a porous body in an active material raw salt solution and then converting it into an active material in an alkali, from the second repetition onwards, by rinsing with water after immersing the porous body in the raw material salt solution. A method for producing an electrode plate for an alkaline storage battery, which comprises converting a raw material salt solution into an active material after removing it.