JPS59158070A - Lead storage battery - Google Patents

Abstract

PURPOSE:To give a high tightening pressure to an electrode group so as to improve its life performance by placing separating bodies each consisting of a separator and a retainer, which contains an acid-proof hollow bodies which can be expanded by heating, between plates to make an electrode group, then heating the electrode group after it is inserted in a container. CONSTITUTION:After a retainer consisting of a mat of 0.9mm. thickness is formed by mixing 10wt% of EXPANCEL used as hollow bodies into glass fiber with a mean diameter of 6mum, the retainer is superimposed on a microporous rubber separator of 0.5mm. thickness to make a separating body. The thus made separating bodies are placed between pasted positive and negative plates to make an electrode group. After that, the electrode group having a tightening pressure of 5kg/dm<2> is inserted in a container before being heated to 90 deg.C so as to cause the hollow bodies to foam prior to being cooled, thereby increasing tightening pressure given from the retainer to a positive active material. As a result, high tightening pressure can be easily given to the electrode group, thereby enabling the life performance of the electrode group to be improved by increasing its active-material-holding ability.

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide a lead-acid battery with a long life and less chance of cathode active material falling off.

It is well known that one of the causes of the longevity of lead-acid batteries used in applications that undergo repeated charging and discharging is the softening and falling off of the positive electrode active material. For this reason, Clasod type marine storage batteries are mainly used for such applications, and in paste type marine storage batteries used for such applications, the positive electrode plate is made of glass mat or organic fiber non-woven fabric. A retainer is brought into contact with the retainer, which has the property of preventing substances from falling off. The higher the contact pressure (hereinafter referred to as pressure) between the retainer and the positive electrode active material, the higher.

It is possible to suppress the active material from falling off. However, if this pressure is set too high, it becomes difficult to insert the battery into the battery case.

It is also known that the strain pressure drops significantly when electrolyte is injected, making it extremely difficult to practically manufacture lead-acid batteries with high strain pressure.

The present invention overcomes these conventional drawbacks, and has a long life with less shedding of the positive electrode active material.

Moreover, the present invention provides a lead-acid battery that is easy to manufacture. That is, according to the present invention, the retainer includes at least a separator formed of a retainer including an acid-resistant hollow body that expands when heated and a separator stacked thereon, and a positive electrode plate and a negative electrode plate. The electrodes are overlapped so as to touch the positive electrode plate to form an electrode group, and the electrode group is inserted into a battery case under low pressure, and then fully heated to expand the hollow body and apply high pressure to the electrode group. .

Hereinafter, the present invention will be explained in detail with reference to one embodiment thereof. That is, glass fibers having an average fiber diameter of 6 μη2 were used, and 10 layers of EXPANCEL (Nippon Phyllite Co., Ltd.) were placed therein as hollow bodies. An electrode group in which a separator consisting of a mat of thickness Q, 9 ml used as a retainer, and a microporous rubber separator of 0.5 mm thick, placed between a paste-type positive electrode plate and a negative electrode plate. It was created. At this time, the retainer was brought into contact with the positive electrode plate. The pressure on this extreme group is 5,
It was inserted into a battery case at 9/da. Next, the battery case is FRP
The hollow body was heated to 90° C. to foam, cooled, and removed from the outer box. Glue this lid and inject electrolyte to make 100AH1 according to the present invention.
A 5I (H) lead-acid battery A was obtained. This was subjected to an alternate charge-discharge life test in which one cycle consisted of discharging at 25 A for 6 hours and charging at 18 A for 5 hours, and the results shown in Figure 1 were obtained. In Figure 1, the @! group, which uses glass fiber with an average fiber diameter of 19 μm as a retainer and the same parts as lead-acid battery A in other respects, is inserted into the battery case under a pressure of 9/20. The results of the same test conducted on conventional lead-acid battery B are also shown.

As is clear from the results shown in FIG. 1, the lead-acid battery A according to the present invention has a lifespan approximately 1.5 times longer than that of the conventional lead-acid battery B. This is because the hollow body expands when the electrode group is heated after being inserted into the battery case, which increases the pressure on the positive electrode active material in the retainer, increasing the active material holding capacity of the retainer. .

In the step of expanding the hollow body, if the battery case is a thermoplastic synthetic resin such as polypropylene ABS, it should be made of a metal such as iron or a heat-resistant material such as FRP to prevent the battery case from swelling due to heating. It must be placed in an outer box made of synthetic resin and heated.

Furthermore, since the hollow body in the retainer is directly exposed to the electrolyte, substances harmful to the lead-acid battery must not be eluted in the electrolyte, and therefore, resistance to sulfuric acid and oxidation is required.

In the present invention, the tension achieved depends on the amount of hollow bodies present in the retainer. Therefore, the proportion of hollow bodies in the retainer can be adjusted in order to achieve increased pressure. At the same time, the tension changes depending on the overall volume of the retainer. Therefore, in the case of the same electrode plate gap, the larger the ratio of the retainer to the separator, the more the separator will try to maintain its thickness over a long period of time. .

Tension is maintained for a long time. Therefore, it is desirable that the separator be as thin as possible and the retainer as thick as possible. In the most desirable embodiment of the present invention, the proportion of the hollow body in the retainer is 2 to 50% by weight, and the proportion of the thickness occupied by the retainer between the poles is 40 to 95%.

Organic fiber nonwoven fabric can also be used as the material for the parts other than the hollow body of the retainer, but it is acid resistant.

Glass fibers with a fiber diameter of 0.1 to 14 μl are suitable from the viewpoint of active material retention. Among these, the optimum fiber diameter is 1.5 to 11 μm to achieve both the contradictory characteristics of ease of electrolyte diffusion and active material retention.

As described above, according to the present invention, it is possible to provide a lead-acid battery with a long life in which the positive electrode active material is less susceptible to softening and falling off, and therefore has great industrial value.

[Brief explanation of drawings]

FIG. 1 is a graph showing the life performance of a lead-acid battery A according to the present invention and a conventional lead-acid battery B. Applicant Yuasa Battery Co., Ltd.

Claims (1)

[Scope of Claims] 1) A lead-acid battery having an electrode group in which a separator including at least a retainer and a separator is arranged between a positive electrode plate and a negative electrode plate, in which the retainer has an acid-resistant hollow property that expands when heated. What is claimed is: 1. A lead-acid battery, characterized in that the retainer is in contact with a positive electrode plate. 2) By inserting the electrode group into the battery case and heating it,
The lead-acid battery according to claim 1, characterized in that a hollow body in the retainer is expanded to apply high tension to the pole group.