JPS6054741B2 - Manufacturing method of electrode plates for lead-acid batteries - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synthetic fiber added to an active material of an electrode plate for a lead-acid battery.

Conventionally, the active material of electrode plates for lead-acid batteries has a thickness of 2 to 5 denier and a length of 0 to prevent the active material from falling off during the electrode plate manufacturing process, lead-acid battery assembly process, or lead-acid battery use. A synthetic fiber made of a copolymer of acrylic and vinyl chloride, for example, having an acid resistance of about .5 to 3 mm is mixed.

However, since the synthetic fibers described above have smooth surfaces, they have poor adhesion to the active material, and cannot be said to be sufficiently effective in preventing the active material from falling off.

Although the effect of adding synthetic fibers to prevent the active material from falling off can be expected to some extent by increasing the amount of synthetic fibers added or increasing the length,
On the other hand, there is a limit to increasing the amount added or increasing the length because there is a risk that it may cause problems in the equipolar plate manufacturing process due to poor filling of the paste into the grid substrate. be. Therefore, in recent years, attempts have been made to change the cross-sectional shape of synthetic fibers or to process the fibers into a wavy shape, but these efforts are often ineffective and impractical.

In view of the above points, the present invention aims to improve the adhesion with the active material by making the added synthetic fiber retain porosity, thereby forming unevenness uniformly on the fiber surface, thereby reducing the dropout of the active material. The purpose is to reduce the occurrence of defects in the electrode plate manufacturing process and lead-acid battery assembly process, and thereby extend the battery life.

The present invention will be described in detail as follows.

A raw material consisting of a polyolefin synthetic resin, a filler, and a plasticizer is heated and kneaded, and then processed and molded into fibers having a predetermined thickness.

Thereafter, the plasticizer or both the plasticizer and the filler are eluted or extracted with a suitable solvent to form small pores in the fibers.
The filler applicable to the present invention is one for adsorbing and retaining a large amount of plasticizer on the surface, and includes fine silica powder, carbon black, and the like. Furthermore, fillers such as calcium carbonate, magnesium carbonate, etc., which are easily eluted or extracted and form pores after their escape, may also be used. The synthetic fiber thus obtained has uniform irregularities formed on its surface. Since the paste enters into the small pores on the fiber surface during paste kneading, the adhesion between the active material and the fibers becomes extremely excellent. The size and amount of pores formed and the strength of the fibers can be changed by changing the particle size of the filler and the proportion of the plasticizer.

In practice, size ranges of about 10 microns or less are possible, but the lead powder particles currently in use range from 0.5 to 1.
Since most of the particles are on the order of microns, ideally, the adhesiveness with the active material is better when the thickness is 1 micron or more. Furthermore, if the amount of filler is increased to improve the adhesion with the active material, the strength of the fibers becomes brittle, and if the amount of resin is increased to increase the strength of the fibers, the adhesion with the active material decreases. Overall, the optimum blending ratio of the three components is resin/filler/plasticizer=15-3V8-17/58-75 (all weight %). Example 1 Pellet-shaped low-density polyethylene (25% by weight) and silica powder (average particle size 1.5 μm)
, 15% by weight) and the plasticizer dioctyl phthalate (D,O
, P) (60% by weight) were mixed in a mixer to prepare a raw material.

This raw material was heated and kneaded at 200±1 (generations) and then extruded to obtain long fibers having a thickness of about 3 deniers. Thereafter, the plasticizer in the fibers was extracted by ultrasonication in a trichlorethylene solution to make the fibers porous. The synthetic resin thus obtained was cut into lengths of approximately 1 mm. This was added at a ratio of 0.0% by mass to the lead powder, and the paste was kneaded in the same predetermined manner as in the prior art, and then filled into a grid substrate to obtain an electrode plate. Example 2 Pellet-shaped low-density polyethylene (
25% by weight), carbon black (5% by weight), silica powder (1% by weight) and petroleum oil (6% by weight).
) was mixed with a mixer to obtain a raw material.

Thereafter, porous fibers were obtained in the same manner as in Example 1, and the paste was added to lead powder, kneaded, and then filled into a grid base to obtain an electrode plate. Next, the amount of active material that fell off when the chemically formed anode plate obtained according to the present invention was dropped from a height of 5 hours onto an iron plate alternately on the front and back sides is as shown in the drawing.

As is clear from the drawings, it can be seen that in the electrode plate to which the porous fibers according to the present invention were added, the active material did not fall off much, and the strength of the active material was improved. Similar results were also obtained for electrode plates that were not chemically formed.

The length, thickness, and amount of the porous synthetic fibers added to the electrode plate according to the present invention shown in the drawings were the same as those of the conventional electrode plate.

In the drawings, A represents a conventional electrode plate, and B represents an electrode plate according to the present invention.

As described above, according to the present invention, defects caused by falling off of active material from electrode plates in the manufacturing process of storage batteries are significantly reduced, and
No short circuit occurs at the bottom of the electrode plate group due to fallen active material.
It has great industrial value, such as improving the life performance of storage batteries.

[Brief explanation of the drawing]

The drawing shows the electrode plate obtained by the present invention and the conventional electrode plate.
It is a comparative diagram showing the amount of active material falling off when dropped from a height of 0 (1). A is a conventional electrode plate, and B is an electrode plate according to the present invention.

Claims (1)

[Claims] 1 Raw materials consisting of a polyolefin synthetic resin, a filler, and a plasticizer are heated and kneaded, then formed into a fiber having a predetermined thickness, and then the plasticizer or the plasticizer and filler are eluted or extracted to maintain porosity. 1. A method for producing an electrode plate for a lead-acid battery, which comprises cutting porous fibers into a predetermined length and adding the cut fibers to a paste.