JPS59138059A - Sealed lead battery - Google Patents

Abstract

PURPOSE:To obtain a low-cost lead battery while keeping its excellent performance by placing a flexible separator containing acid-proof minute hollow bodies which can be expanded by heating between a positive and a negative plate. CONSTITUTION:A flexible separator containing acid-proof hollow bodies which can be expanded by heating, is placed between a positive and a negative plate. A larger proportion of hollow bodies in the separator is desirable since it decreases the apparent density of the separator. However an extremely large proportion of hollow bodies in the separator makes the apparent density excessively low. It is appropriate that the proportion of hollow bodies in the separator be 2-20wt% (preferably 2-60wt%). The separator may contain, in addition to the hollow bodies, glass fiber, diatomaceous earth, acid-proof fiber or pulverized powder such as pulverized silica, pulverized perlite powder or organic fiber and a binder for connecting these matters.

Description

[Detailed description of the invention] The present invention relates to a sealed lead-acid battery.

The aim is to provide high performance and low cost batteries.

Sealed lead-acid batteries use the so-called 02 cycle, in which oxygen gas generated from the positive electrode plate reacts with the negative electrode plate at the end of charging, and are sealed to prevent electrolyte from disappearing from the battery system. There are two methods, one is to maintain this reaction by gelling the electrolyte, and the other is to maintain this reaction by absorbing the electrolyte into a highly absorbent separator.
There are two methods. The present invention particularly relates to the latter method.

In other words, the separator of this method is #ll diameter 1μ
A separator formed into a sheet shape consisting mainly of glass fibers smaller than m without using any organic substances is most suitable.

However, such glass fibers are extremely expensive, and sealed lead batteries using them must also be expensive.

As a separator that overcomes these drawbacks, the fiber diameter is 1μ.
Mainly made of glass fiber with a diameter of 1 μm or less
A separator (hereinafter referred to as a separator) that does not contain any organic substances and is made by randomly mixing thicker glass fibers, preferably 10 μrn to 60 μm.

There is a separator (called separator X). That is, such a separator has an apparent density of 0.1 under a load of 20 kQldA.
6 to 0.149/cc, which is a high-density separator that contains some organic matter compared to the previous ones. It is smaller than c and about 60% cheaper. Furthermore, although it contains no organic substances and has good battery properties, it is still more expensive than ordinary, inexpensive separators.

The present invention relates to a sealed lead-acid battery equipped with a separator that overcomes these drawbacks.

Next, the present invention will be explained by examples.

Example 1 70% acid-resistant glass fiber with a fiber diameter of 0.7 μm and EXP
60% of ANCEL (manufactured by Nippon Ferrite Co., Ltd.) was dispersed in water, made into paper using a conventional paper machine, dehydrated, and dried to obtain a separator according to the present invention (hereinafter referred to as separator a).

The drying temperature at this time was 95°C. The obtained separator a had the characteristics shown in Table 1.

AH Using this, a sealed lead-acid battery A with a capacity of 15HH was obtained by a normal assembly method.

1st bale Example 2 100 parts of diatomaceous earth with an average particle diameter of 600 mμ, 15 parts of SBR latex, 25 parts of EXPANCEL, 10 parts of water
A paste obtained by kneading a mixture consisting of 0.00 parts was extruded into a sheet shape, and heated and cured at 160°C to obtain separator b of the present invention.

This separator b had the characteristics shown in Table 2. Also, using this, a sealed lead battery B having a capacity of 4 AH/s HR was obtained.

Example 5 The dispersion medium used in Example 1 was dilute sulfuric acid with a specific gravity of 1.05 ci, and the undried upper parator with a moisture content of 15% was placed in a metal outer box according to the same handling method as for ordinary separators.
It was heated to 20°C to foam the separator, pressure was applied to the electrode group, and then it was cooled, taken out from the iron outer box, and electrolyte was poured into it to obtain a sealed lead-acid battery C with a capacity of 4AH15HR.

Sealed lead battery A obtained in each example.

An alternate charge-discharge life test was conducted on B and C, with one cycle consisting of discharging at 1 A for 6 hours and charging at 0.72 A for 5 hours. At the same time, sealed lead batteries X and Y of the same capacity using conventional seven pallets X and Y were also used in this test. The results of the life test were as shown in FIGS. 1 and 2. In FIG. 1, the vertical axis shows the capacity at 0.25°C discharge, and in FIG. 2, the vertical axis shows the amount of liquid loss during the life test.

Looking at the results in FIG. 1, the sealed lead battery A according to the present invention,
It can be seen that B is inferior in performance to sealed lead battery X using separator X, but superior to sealed lead battery Y using separator y. Furthermore, as is clear from FIG. 2, there is no difference in the amount of liquid loss, which indicates gas absorption efficiency, from that of the conventional type.

Since the price of the separator accounts for about 10% of the battery price, the sealed lead-acid battery according to the present invention is 4 to 7% cheaper than the conventional one.

The sealed lead-acid battery C according to the present invention has a longer life performance than the conventional sealed lead-acid battery, but I imagine that this is because the pressure between the electrode plate and the separator is increased compared to the conventional product.

Hollow bodies must be acid and oxidation resistant. The larger the proportion of hollow bodies in the separator used in the sealed lead-acid battery of the present invention, the lower the apparent density of the separator, which is desirable.

If the amount is too large, it becomes too coarse, the pore size becomes large, and the cost of the hollow body is high, which cancels out the effect of the apparent density range, which is not desirable.

Therefore, the ratio before foaming is 100% of the other constituent materials of the separator.
2 to 200, more preferably 2 to 60, is appropriate. The constituent materials of the separator other than the hollow body include glass fiber and diatomaceous earth shown in the examples, as well as finely ground silica,
It is possible to use acid-resistant fibers such as fine perlite powder, organic fibers, fine powders, and binders to bind amounts of these substances.

As described above, the sealed lead-acid battery according to the present invention maintains excellent performance and is inexpensive, so it has great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the alternate charging and discharging life characteristics of the present invention and the conventional sealed lead-acid battery, and FIG. 2 is a graph showing the amount of liquid loss at that time. Applicant Yuasa Battery Co., Ltd.

Claims (1)

[Scope of Claims] 1) A sealed lead-acid battery characterized in that a flexible separator containing acid-resistant microscopic hollow bodies that expands when heated is disposed between a positive electrode plate and a negative electrode plate. 2) The proportion of the hollow body in the entire flexible separator is 2 to 2.
Claim 1 characterized in that the amount is 60% by weight.
Sealed lead-acid batteries as described in section.