JPS6028168A - Manufacture of negative plate for nickel cadmium storage battery - Google Patents

Abstract

PURPOSE:To reduce clogging of pores through adhesion at the surface and increase amount of active substance for impregnation by utilizing immersing solution mixing the specified amount of cadmium acetate into cadmium nitric acid bath at the time of chemical impregnation of sintered type negative plate. CONSTITUTION:An immersing solution mixing cadmium acetate of 20% or more in the cadmium nitric acid bath is used at the time of chemical impregnation of sintered type negative plate. Thereby, clogging of pores at the surface of sintered body by adhesion at the surface can be reduced and amount of impregnation of active substance on the sintered type negative plate can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in cathode plates for nickel-cadmium storage batteries, and in particular to increasing the amount of impregnation of sintered cathode plates in chemical impregnation.

Chemical impregnation methods, electrolytic impregnation methods, and melt impregnation methods are generally known as methods for manufacturing sintered cathode plates. The chemical impregnation method uses Cd(OH) as the active material.

Although the chemical impregnation method has many advantages such as active material utilization rate and productivity,
The amount of active material impregnated is inferior to the other two methods. The reason why the amount of active material impregnated is small is largely due to the principle of the impregnation method itself, but is it also due to clogging of pores on the surface of the sintered body due to surface adhesion? There's no way we'll overlook this one contributing factor.

The purpose of the present invention is to mix 1 ml of chemical impregnation liquid into a cadmium nitrate bath with 20% or more cadmium acetate.
This aims to significantly reduce clogging of pores due to surface adhesion tζ and increase the amount of active material impregnated.

Next, one embodiment of the present invention will be described.

FIG. 1 shows the cycle change in the weight of active material impregnated. A is a case of a cadmium nitrate solution, and B is a case of a mixed solution of 40 cadmium thiacetate and cadmium nitrate. Up to the 3rd cycle, both A and B are almost the same, but after the 4th cycle in A, there is a tendency for the amount of impregnation to reach a plateau, which is thought to be due to clogging. On the other hand, B does not show a tendency to reach a plateau even in the 6th cycle. The reason for this is thought to be influenced by the shape and size of the active material cd(OH)t, as shown in FIGS. 3 and 4. In Figure 3, several μm
It can be seen that large Cd(OH) crystals of about lQ71m were formed, and the surface of the sintered body (code 3) was almost covered. In contrast, in Figure 4, the c
d(OH)t (code 4) is observed, and even in the 6th cycle, the partial force 9 of the sintered body is exposed. The influence is shown in Figure 2. By mixing 20 or more cadmium acetate in this way, the amount of impregnation increases and becomes almost constant at about 50 tem.

As described above, the present invention has great industrial value, such as being able to increase the amount of impregnation of a sintered cathode plate in chemical impregnation.

[Brief explanation of drawings]

Figure 1 is a curve diagram showing the impregnation cycle dependence of the amount of active material impregnated, Figure 2 is a curve diagram showing the influence of acetic acid concentration on the amount of active material impregnated, and Figure 3 is a curve diagram showing the influence of acetic acid concentration on the amount of active material impregnated. FIG. 4 is an explanatory view of the surface of the electrode plate obtained by impregnation with a cadmium nitrate solution. patent applicant

Claims (1)

[Claims] A method for manufacturing a logic electrode plate for a nickel-cadmium storage battery, characterized in that an immersion solution containing 20% or more of cadmium acetate in cadmium nitrate is used during chemical impregnation of a sintered cathode plate.