JP2855706B2 - Sealed lead-acid battery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sealed lead-acid battery used for repeated charging and discharging.

2. Description of the Related Art Most of the sealed lead-acid batteries currently on the market are so-called retainer types, in which a positive and negative electrode plate and a separator mainly composed of fine glass fibers are impregnated and held with an electrolytic solution. Things. This closed lead storage battery of the retainer type has a problem that the cost is high, though the performance is not inferior to that of the conventional open lead storage battery. The high cost is due to the use of an expensive separator having a high liquid holding capacity, such as a fine glass fiber separator (hereinafter referred to as a glass separator), for impregnating and holding the electrolyte between the electrode plates. is there. In order to solve this cost increase, it has recently been attempted to use a powder made of an inorganic oxide such as SiO ₂ instead of a glass separator or the like as an electrolyte holder. However, when powder is used, there is a drawback that the battery performance is significantly affected by the particle size of the powder, and the performance is inferior to the conventional retainer type. For example, when powder having a small particle size is used, the porosity is reduced, and not only the amount of retained electrolyte is reduced, but also the passage required for diffusion of the electrolyte is narrowed. It is significantly lower than the formula. On the other hand, if the particles of the powder used are sufficiently large, the above-mentioned drawbacks are eliminated, but the ability to retain the electrolytic solution is reduced, and the specific gravity difference in the vertical direction of the electrolytic solution when deep charge / discharge is repeated, so-called electrolytic solution A phenomenon called stratification occurs. If the battery is used in a state where the electrolyte is stratified, lead sulfate is concentrated and accumulated in the lower positive and negative plates exposed to high concentration sulfuric acid, and this lead sulfate is not activated even when charged. In addition, the capacity of the battery may be reduced. As described above, when the above-described powder is used as the electrolyte holder instead of the glass separator, performance comparable to that of the conventional retainer type battery cannot be obtained.

Means for Solving the Problems The present invention fills the peripheral portion of the electrode plate group and the gap between the positive and negative electrode plates with an acid-resistant and oxidation-resistant powder, and absorbs the electrolytic solution into the positive and negative electrode plates and the powder. In a lead-acid battery having a holding structure, the above problem is solved by making the particle size of the powder at the bottom of the battery smaller than that at the top of the battery.

Example A retainer type battery according to the present invention was manufactured and tested. This is described in detail below.

First, an electrode plate group including a paste-type positive electrode plate and a negative electrode plate having a height of 260 mm was prepared, and this was stored in a battery case. Next, 600 g of powder containing SiO ₂ as a main component and having different particle diameters was charged in two portions. That is, after filling the lower part of the battery with 300 g of powder having a particle diameter of 50 to 100 μ, the particle diameter is 200 to 400 μ.
300 g of powder was filled thereon. Thereafter, a predetermined amount of diluted sulfuric acid is injected, and a safety valve and the like are attached according to a conventional method.
A 2V-200Ah retainer type battery A according to the present invention was obtained. Further, for comparison, a battery B filled with only powder having a particle diameter of 200 to 400 μ, a battery C filled only with powder having a particle diameter of 50 to 100 μ, and a conventional battery using a glass separator as an electrolyte holder were used. A retainer type battery D was manufactured. Table 1 shows the discharge capacities of these batteries. The values in the table are shown as ratios to the discharge capacity of the conventional retainer type battery D.

Although the discharge capacity of the battery A according to the present invention is inferior to that of the battery B filled only with a powder having a large particle diameter, the discharge capacity is not inferior to that of the conventional retainer type battery D even at a high rate discharge or a low rate discharge. You can see that.

On the other hand, regarding the life performance, the terminal voltage is 1.
It was evaluated by a charge / discharge cycle test in which the battery was discharged to 70 V and then charged at 2.35 V for 24 hours. FIG. 1 shows the transition of the discharge capacity. From this figure, it can be seen that the capacity change of the battery B filled only with the powder having a large particle diameter is extremely poor. Table 2 shows the specific gravity difference between the electrolyte at the top and the bottom of the battery when the discharge capacity is less than 75% of the initial value. In the case of battery B, the electrolyte is significantly stratified and the life performance is low. It is considered to have decreased. In contrast,
In the battery A according to the present invention, stratification of the electrolytic solution hardly occurs, and the life performance is comparable to that of the conventional retainer type battery D. In the battery A according to the present invention, the electrolyte is not stratified because the particle size of the powder that can prevent the stratification of the electrolyte differs depending on the height of the electrode plate. It is necessary to make the diameter 50 to 100 μm, but if the height is half that, the powder having a coarser particle diameter can prevent stratification of the electrolytic solution. In other words, a powder having a large particle diameter has a weak force for holding the electrolytic solution, but as the height of the battery decreases, the force for flowing down the concentrated sulfuric acid generated during charging decreases. It is considered that the stratification can be prevented even with a coarse powder accordingly.

In this example, silicon oxide was used as the powder, but the powder was aluminum, titanium, an oxide such as magnesium, or a mixture thereof.
The effect of the present invention is the same. Further, in this example, the particle size of the powder to be filled in the lower part of the battery was 50 to 100 μ, and the particle size of the powder to be filled thereon was 200 to 400 μ. It is determined by the type of powder. Further, in the present embodiment, the powder is filled in two stages, but it goes without saying that a battery with higher capacity and longer life can be obtained by increasing the number of times of filling (the number of stages).

Effect of the Invention As described above, the structure in which the peripheral portion of the electrode plate group and the gap between the positive and negative electrode plates are filled with an acid-resistant and oxidation-resistant powder, and the positive and negative electrode plates and the powder absorb and hold the electrolytic solution. In the lead-acid battery having the above, the stratification of the electrolytic solution can be prevented without lowering the discharge capacity by increasing the particle size of the powder to be filled toward the upper part of the battery. As a result, a large-capacity sealed lead-acid battery having high capacity and long life can be obtained at low cost, and its industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 shows a battery A and other batteries B and D according to the present invention.
3 shows the transition of the discharge capacity at the time of the life test.

Claims (1)

(57) [Claims] An acid- and oxidation-resistant powder is filled in a peripheral portion of an electrode plate group composed of a positive and negative electrode plate and a porous separator and a gap between the positive and negative electrode plates. What is claimed is: 1. A lead-acid battery having a structure in which a body absorbs and retains an electrolyte, wherein the particle size of the powder at the bottom of the battery is smaller than that at the top of the battery.