JPS5945187B2 - 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, cathode plates for lead-acid batteries are made by adding additives such as 0.2 to 1% barium sulfate and 0.2 to 1q6 lignin to a lead compound powder whose main component is 65 to 80% lead oxide. It is filled with a paste (active material) manufactured by mixing with dilute sulfuric acid, and lignin is said to be effective in improving high rate discharge performance and life performance, but it However, the disadvantage is that the lignin is eluted or dispersed from the cathode plate into the electrolyte wax, and its effectiveness is gradually lost.

However, for this reason, even if a large amount of lignin is included in the cathode plate in advance, the charging overvoltage will increase, making charging difficult, or the active material will expand easily, causing short circuits, resulting in high rate discharge. Since C does not maintain performance and life performance, in order to maintain the performance of the cathode plate for as long as possible,
The problem was always keeping the amount of lignin within the optimum range. The present invention has been developed in view of the above problems, and involves holding a porous body containing lignin inside the active material layer of the cathode plate, and leaching lignin from the porous body into the active material layer little by little during use. The amount of lignin in the active material is kept within the optimum range at all times. The porous body that retains lignin is made by adding a filler and a plasticizer to a polyolefin resin, heating and kneading it, and then extruding it to form a lattice body with a lead alloy current collector. Alternatively, by extracting the filler, a current collector constituting the lattice body can be obtained in an integrated state, and the porous body also serves as an active material holder together with the current collector. Lignin is retained in the porous body by immersing the lattice body including the porous body in a solution dissolved or dispersed in water, and then drying to evaporate the water.

The amount of lignin contained in the porous body can be adjusted by the porosity of the porous body and the lignin concentration in the solution, and is suitably 0.5 to 5 times the amount added in advance to the paste.
The final decision will be made depending on how the lead-acid battery is used. An example of the manufacturing method of the present invention will be explained.

Pellets of low density polyethylene, fine silica powder and plasticizer dioctyl phthalate in a ratio of 20:20, respectively.
: Mixed in a mixer at a ratio of 60 (wt%), 180~
After further kneading at 220°C, a current collector made of lead alloy is integrated by extrusion molding to form a lattice body, and then the plasticizer in this lattice body is extracted with trichlorethylene to make a porous body. The body is immersed in an aqueous solution containing lignin dispersed at a ratio of 1:3 for about 1 minute, and then dried at 60°C to evaporate the water and retain the lignin in the lattice. (Contains 0.5% lignin) to produce a cathode plate.

N5OZ type lead-acid battery obtained according to the present invention (invention product A
) and a conventional lead-acid battery of the same shape (conventional product B), the relationship between high rate discharge performance at low temperature (-15°C) and charge/discharge cycle 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, initial, 2.
000th cycle, 4.000th cycle, 6.00
These are the results of measuring the duration of high rate discharge at 300 A in the 0th cycle. From the above results, it was found that the product A of the present invention has a higher high rate discharge performance than the conventional product B, and maintains a high level with little change over time.

Further, since the porous body according to the present invention functions as an active material holder by being integrated with the lead alloy current collector, the weight of the lead alloy occupying the lattice body can be reduced. As mentioned above, the cathode plate for a lead-acid battery of the present invention has a porous body impregnated with lignin that is integrated with a grid body and held inside the active material of the cathode plate, so that it can be easily mixed with a paste using a normal method. Even if the added lignin dissolves into the electrolytic solution or decomposes and its effectiveness decreases, the lignin contained in the porous material gradually leaches into the active material and is replenished. It is of great industrial value in that it is possible to sustain the effects of this method, improve high rate discharge performance and life performance, and also reduce the weight of the electrode plate.

[Brief explanation of the drawing]

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 obtained according to the present invention and a conventional lead acid battery.

Claims (1)

[Claims] 1 After heating and kneading a mixture consisting of a polyolefin resin, a filler, and a plasticizer, it is integrated with a current collector made of a lead alloy by extrusion molding to form a lattice body, and then the plasticizer or filler in the lattice body is 1. A method for producing a cathode plate for a lead-acid battery, characterized in that lignin is contained in the pores of a porous body obtained by extracting an agent.