JPS6043630B2 - Manufacturing method for electrode plates for nickel-cadmium storage batteries - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an anode plate and a cathode plate for a nickel-cadmium storage battery, and in particular, it impregnates a large amount of active material into the pores of an electrode substrate by reducing the number of operations in a series of steps. Therefore, the purpose is to simplify the manufacturing process and shorten the time.

Conventionally, electrode plates for nickel-cadmium storage batteries have been made by sintering fine powder of nickel or other material to form a porous substrate, and these porous parts are impregnated with nickel hydroxide salt for the anode and cadmium salt for the cathode in the form of an aqueous solution. Alternatively, these salts are impregnated in the form of a molten salt and retained, and then the substrate impregnated with the above salts is electrolyzed or thermally decomposed in an alkaline electrolyte to form an active material, which is then washed with water and dried. This series of operations was repeated several times to obtain a predetermined amount of impregnation. However, the former method requires a series of repetitions of 6 or more times as the amount of impregnation at one time is small, which is extremely disadvantageous in terms of mass production. It requires soaking for a long time, and the first impregnation operation results in more impregnation than the former, but after that, the impregnation efficiency becomes extremely low, and it takes a very long time to obtain the required amount of impregnation. .

That is, as shown in FIG. 1, in the conventional method, a series of steps consisting of the impregnation step A) electrolysis step B) washing step C) drying step D is repeated six times, so that the electrolysis step other than the impregnation step is In addition, the next step of washing the electrolytic solution adhering to the substrate with water takes up a large proportion of the operating man-hours and operating time, resulting in inefficiency. The present invention has been made to eliminate the above-mentioned drawbacks, and the salt solution of the active material impregnated into the substrate in the impregnation process can be dried even before it is deposited and fixed in the electrolytic process, thereby making it easier to repeat the impregnation operation. This is based on the discovery that it can be held to a substrate to a durable extent.

That is, as shown in FIG. 2, in the present invention, for example, 1
A series of steps in which the combined operation of drying step D' of drying in a dry atmosphere at a temperature of 00±2 lC is repeated a necessary number of times, for example, 2 or 3 times, followed by electrolysis step B, water washing step C, and drying step D. An electrode plate can be manufactured by repeating this process about 3 or 4 times.

However, the repetition of the combination of impregnation step A and drying step D' includes the possibility of omitting the final drying step D'' of the repetition.

An embodiment of the present invention will be described with respect to an anode plate.

Nickel nitrate N1(NO3)2.6H20 is melted at a temperature of about 70°C, and a small amount of water is added to adjust the specific gravity to about 1.7. First, a porous substrate made by sintering carbonyl nickel powder in this aqueous solution is immersed for about 1 minute to impregnate it with the nickel nitrate aqueous solution. Next, this board was coated with about 10
Dry for about 3 to 4 minutes in a drying oven at a temperature of 0 ± 20'C,
The substrate is immersed in the aqueous solution again. After dipping, the substrate was placed in a drying oven to dry as described above, and then this substrate was used as a cathode for 8 hours.
Two batches of electrolysis are performed in a caustic soda aqueous solution having a concentration of 25% at 0° C. to deposit a nickel hydroxide active material in the porous portions of the substrate, which is washed with water and dried. The above series of steps is repeated three times to obtain an anode plate. In the case of the cathode plate, it may be similarly impregnated with cadmium nitrate. FIG. 3 shows changes in the amount of active material impregnated with respect to the number of repetitions of a series of substrate steps for the method according to the present invention and the conventional method.

It can be seen that in the product X according to the present invention, the number of repetitions of the series of steps is halved compared to the product Y according to the conventional method, and a predetermined amount of impregnation can be obtained. Furthermore, when the active material utilization rate of the obtained electrode plate was measured, it was found that the electrode plate obtained according to the present invention was 8.
4% to 992%, resulting in an approximately 10% improvement in characteristics compared to 78 to 90% for conventional electrode plates. In this example, the temperature of the drying process was set to about 100±20°C and the time was set to about 3 to 4 minutes, because if the temperature exceeds 120°C and for a long time, the impregnated material becomes inactive and the active material deteriorates. This is because not only the utilization rate decreases but also a part of the sintered body of the board may corrode and the strength of the electrode plate may deteriorate.
This is because the effect of increasing the amount of impregnation cannot be obtained much below the temperature.

As mentioned above, electrolysis can improve manufacturing efficiency by simplifying and shortening the number of manufacturing steps and time, and has great industrial value in that it can obtain electrode plates with improved characteristics. be.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing the steps in the conventional manufacturing method of electrode plates for nickel-cadmium storage batteries, FIG. 2 is a process diagram showing the steps in the present invention, and FIG. 3 is a series of steps in FIGS. 1 and 2. 3 is a comparison curve showing the change in the amount of active material impregnated with respect to the number of repetitions. A is the impregnation process, B is the electrolysis process, C is the water washing process, D, D″
is the drying process, X is by the method of the present invention, and Y is by the conventional method.

Claims (1)

[Claims] 1. In a method for manufacturing electrode plates for nickel cadmium storage batteries, which consists of repeating a series of steps of impregnation, electrolysis, washing, and drying, the impregnation step and electrolysis step are conducted at a temperature that does not cause thermal decomposition of the impregnated material. 1. A method for producing electrode plates for nickel-cadmium storage batteries, characterized by providing a drying step for a certain amount of time, repeating a combination of an impregnating step and a drying step, and then proceeding to an electrolytic step.