JPS5945186B2 - Manufacturing method for cathode plates for lead-acid batteries - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a cathode plate for a lead-acid battery that improves high-rate discharge performance.

Conventionally, the paste for the cathode plate for lead-acid batteries is a powder of a lead compound containing 65 to 80% lead oxide as a main component.
It is manufactured by adding additives such as about 1% lignin and about 0.2 to 2% barium sulfate and kneading with dilute sulfuric acid.

The above additive, lignin, is effective in improving high-rate discharge performance and life performance, especially at low temperatures, but if too much is added, the charging overvoltage will increase, making it difficult to charge, and the active material will expand, making short circuits more likely. This tendency of the active material to expand and short-circuit is remarkable when the active material is used in a deep charging/discharging state where the inside of the active material is utilized.

In addition, when used in a shallow charging/discharging state where only the surface layer of the active material is used, such as in the case of high rate discharge, the cathode active material particles aggregate and the reaction area decreases, resulting in a decrease in performance. is remarkable. The present invention solves the above-mentioned problems by improving high-rate discharge performance, preventing the active material from expanding even when used in a deep charging/discharging state, and preventing the active material from expanding even when used in a shallow charging/discharging state. In order to produce cathode plates for lead-acid batteries that do not significantly agglomerate, a regular paste is filled into the plate grid, and then a fine powder mixture of additives such as lignin, barium sulfate, and carbon is sprayed onto the surface of the paste. (or coating method) to make the additive concentration in the surface layer of the paste higher than in the inside.

An embodiment of the present invention will be described.

Powder of a lead compound whose main component is 65 to 80 t of lead oxide, 0.2 to 1 t of lignin, 0.3 to 2 t of barium sulfate,
An ordinary paste obtained by kneading additives with L-added dilute sulfuric acid at a ratio of 0.1 to 0.5 q6 carbon is filled into an electrode grid, and the paste is heated and dried until the water content in the paste is reduced to about 5 to 10 g. After removing it, a solution of twice the amount of lignin, barium sulfate, and carbon additive mixed powder evenly dispersed in 100 ml of water was sprayed onto the surface of the electrode plate, and then dried. It is then aged to produce cathode plates for lead-acid batteries.

The additive mixing ratio of lignin, barium sulfate, and carbon is preferably in the range of (5 to 10): (5 to 10): (1 to 2), and the amount of additive to be deposited is 10 to 10 per electrode plate.
100m9 is an appropriate amount. Additives can be applied by spraying using compressed air or by spraying or coating after dispersing them in water, but in order to make them adhere uniformly, spraying or coating after dispersing them in water is recommended. A good method is to apply it. In this case, if the water in the paste is temporarily removed, the amount of adhesion can be increased by stacking additive solutions with the same concentration. Therefore, in the cathode plate obtained as described above, the additive concentration on the surface part is higher than in the inside, so that ligning gives appropriate expansion to the surface part of the active material in the lead-acid battery.
The contact area for electrochemical reactions is increased to improve high-rate discharge performance, but since the inside of the active material remains the same as before, the active material does not peel off from the electrode grid, thereby extending the life of the lead-acid battery. It will not be shortened.

An N5OZ type lead-acid battery using the cathode plate obtained according to the present invention (invention product A) and a conventional lead-acid battery of the same type (conventional product B)
), the relationship between high rate discharge performance and charge/discharge cycle at low temperature (-15 C) is shown in the drawing.

During a life test based on the SAE standard, where one charge/discharge cycle is charging at 14.8 for 10 minutes and discharging for 2 minutes at 25A, this test was performed at the initial stage, at the 2,000th cycle, and at the 2,000th cycle.
These are the results of measuring the duration of high rate discharge of 300 A at the 4,000th cycle and the 6,000th cycle. From the above results, it can be seen that the present invention product A is the conventional product B
It was found that it has a high rate of discharge performance compared to that of the previous one, and that it maintains a high level with little change over time. As mentioned above, the present invention is of great value in that it allows the production of cathode plates that improve high rate discharge performance without shortening the life of lead-acid batteries.

[Brief explanation of drawings]

The drawing is a curve diagram showing the relationship between high rate discharge performance at low temperature (-15° C.) and charge/discharge cycle of a lead acid battery using the cathode plate obtained according to the present invention and a conventional lead acid battery. A is a product of the present invention, B is a conventional product.

Claims (1)

[Claims] 1 After filling an electrode grid with a normal paste containing additives such as lignin, barium sulfate, and carbon, fine powder of additives such as lignin, barium sulfate, and carbon is sprayed or coated onto the surface of the paste. 1. A method for producing a cathode plate for a lead-acid battery, characterized in that the additive concentration in the paste surface layer is higher than that inside the paste.