JPH01186764A - Sealed type lead storage battery - Google Patents

Abstract

PURPOSE:To make it possible to obtain a sealed type lead storage battery generating no lamination of electrolyte and with an excellent service life property by adding 0.1 to 0.8wt.% of sodium silicate in the electrolyte. CONSTITUTION:In an electrode plate group composed by using separators mainly of a glass fiber and the like, and positive and negative electrode plates, a dilute sulfuric acid including 0.1 to 0.8wt.% of sodium silicate is absorbed and held. As a result, a lamination phenomenon of the electrolyte which makes the density distribution of the dilute sulfuric acid uneven can be prevented. Consequently, a retainer type sealed battery generating no lamination of the electrolyte and with a long service life can be obtained easily and at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a sealed lead-acid retainer battery in which a dilute sulfuric acid electrolyte is absorbed and retained within a group of electrode plates.

Conventional technology and its problems A liquid-retentive separator is placed between the positive electrode plate and the negative electrode plate,
The so-called cage-type dense Wi battery, which is characterized by impregnating the dilute sulfuric acid electrolyte in the separator to such an extent that it cannot be freely released, has been used for various purposes including portable devices due to the demand for maintenance-free construction, and has recently been used for various purposes, including portable equipment. For stationary use.

For automobiles, 1! Expectations are growing for large sealed lead-acid batteries, such as those used in air-powered cars. However, when the electrode plate group is composed of large electrode plates, repeated charging and discharging causes the concentration distribution of the dilute sulfuric acid electrolyte to become uneven, which is the so-called electrolyte stratification phenomenon, which becomes noticeable in W4, and the life performance deteriorates. There is a tendency to In order to prevent this stratification phenomenon, a method has been proposed in which silicon dioxide is added to the electrolyte in an amount of about 1 to 4% to gel it, but the electrolyte becomes fluid in a short period of time. Since the electrolyte is lost, it is necessary to prepare the electrolyte frequently, which poses a problem in that the injection process becomes complicated.

Means for Solving the Problems In view of the above-mentioned problems, it is an object of the present invention to easily and inexpensively provide a long-life sealed retainer battery that does not cause stratification of the electrolytic solution.

That is, in a sealed lead-acid battery, 0.1 to 0
．． 8! Dilute sulfur containing % sodium silicate l11
It is characterized by absorbing and retaining the M solution.

Example Examples according to the present invention will be described below.

Using a separator mainly made of glass fiber with an average diameter of 5 microns or less and large flat positive and negative electrode plates, the total height of the battery is approximately 7.
A 00mm unfilled battery was assembled.

To this unfilled battery, ■ a dilute sulfuric acid electrolyte with a specific gravity of 1.26 (20°C), ■ a 1-sulfur electrolyte with a specific gravity of 1.26 (20°C) containing 3% by weight of silicon dioxide, and ■ sodium silicate. (a) 0.05, (b) 0,1, (C
) O艷, (d) 0,4, (e) O9Ei, (f)
0.8, (a) 1.0 weight percent added, specific gravity 1
．． A dilute sulfuric acid electrolyte of 26° C. (20° C.) was injected into each cell to obtain a 2 V-500 Ah sealed retainer battery. These batteries were repeatedly charged and discharged under conditions of a discharge depth of 75%, a charging t2 amount of 120% of the discharge height, and a temperature of 30°C.

Incidentally, during this cycle test, a capacity test was conducted as appropriate to measure the capacity of the battery. In addition, specific gravity sensors were attached to the upper and lower parts of the electrode plate group, and the specific gravity of the electrolyte during charging was also measured.

Table 1 shows the relationship between the addition m of silicon dioxide and sodium silicate and gelation time, Figure 1 shows the relationship between the number of charge/discharge cycles and discharge capacity, and Figure 2 shows the number of charge/discharge cycles and the upper part of the electrode plate group. and the relationship with the electrolyte specific gravity at the bottom are shown, respectively. It can be seen from FIGS. 1 and 2 that stratification of the electrolytic solution can be prevented by adding 0.1 percent by weight or more of sodium silicate, and there is no decrease in discharge capacity due to this.

However, as shown in Table 1, when 1.0% by weight or more of sodium silicate is added, the gelation time is shortened and workability is deteriorated, similar to when 3% by weight of silicon dioxide is added.

Therefore, the amount of sodium silicate added is 0.1 to 0.8 m
1 percent is appropriate.

Further, sodium silicate is cheaper than silicon dioxide, and is effective in addition to a small amount of addition, so it is advantageous in terms of cost.

Effects of the invention As mentioned above, when sodium silicate is added to the electrolyte from 0.1 to
By adding o, awe percent, a sealed lead-acid battery with excellent life performance without electrolyte stratification can be obtained, and it is also excellent in terms of workability and cost, and its industrial value is extremely large. .

[Brief explanation of the drawing]

Figure 1 shows the relationship between the number of charge/discharge cycles and the discharge capacity of the sealed lead-acid battery of the present invention in comparison with a conventional example, and Figure 2 shows the number of charge/discharge cycles and the electrolyte at the top and bottom of the electrode group. It is a figure showing the relationship with specific gravity.奔 1 Own year 2 Figure hur, t ba? ? Ikuno release

Claims (1)

[Claims] 1. A closed type characterized in that a dilute sulfuric acid electrolyte containing 0.1 to 0.8 weight percent of sodium silicate is absorbed and retained in the electrode plate group consisting of a positive electrode plate, a negative electrode plate, and a liquid-absorbing separator. Lead acid battery.