JPH0883622A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE: To provide a sealed lead-acid battery facilitating the injection of an electrolyte into a battery jar, preventing the stratification of the electrolyte, and capable of prolonging the life. CONSTITUTION: An electrode plate group laminated with a paste positive electrode plate and a paste negative electrode plate via a retainer is arranged in a battery jar. Silica grains 1 of 10-50wt.% having the grain size of 4-6nm and silica grains 2 of the remainder having the grain size of 40-300nm are added to the dilute sulfuric acid having the specific gravity of 1.26-1.35 to form an electrolyte. The electrolyte is injected into the battery jar while being stirred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed lead acid battery.

[0002]

2. Description of the Related Art Retainer type and gel type are known as a method for disposing an electrolyte in a sealed lead-acid battery. The retainer method is a method in which an electrolytic solution holding body (retainer) made of glass fibers holds an electrolytic solution made of dilute sulfuric acid. In addition, the gel method is a method in which about 10 to 20% by weight of silica is added and a gelled electrolytic solution is directly used as an electrolyte without using an electrolytic solution holder. The retainer type has a problem that when the battery is repeatedly charged and discharged, the electrolyte is layered and the life of the battery is shortened. On the other hand, the gel method has a longer life than the retainer method because the electrolyte is not stratified. However, in the gel method, the injection of the electrolytic solution is not easy, and because the electrolytic solution does not move smoothly,
There is a problem that the discharge capacity of the battery becomes small. In particular, the higher the rate of discharge, the smaller the discharge capacity. Therefore, an electrolytic solution holder is arranged between the positive electrode plate and the negative electrode plate, and silica is
A combined system of a retainer type and a gel type in which an electrolytic solution holding body is impregnated with an electrolytic solution which is gelled by adding about 5 wt% is studied.

[0003]

However, even in such a combined system, since the gelled electrolytic solution is used as in the gel system, there is a problem that it is difficult to inject the electrolytic solution into the battery container. If the viscosity of the electrolytic solution is lowered (the gelation is reduced) in order to improve the pouring property of the electrolytic solution, the stratification of the electrolytic solution cannot be prevented, and compared with the battery using the retainer type, Although the life is extended, there is a problem that the life is shorter than that of the battery using the gel type.

An object of the present invention is to provide a sealed lead-acid battery in which the electrolytic solution can be easily poured into the battery case and which has a long life.

[0005]

The present invention relates to silica (Si
For sealed lead-acid batteries using a retainer impregnated with an electrolytic solution containing O ₂ ), 10 to 50% by weight of silica to be impregnated with the electrolytic solution has a particle diameter of 4 to 6 nm, and the rest is 40 to 300 nm. Those having a particle size of If the particle size of the remaining silica is less than 40 nm, the difference in particle size from silica having a small particle size becomes small, and the thixotropic property cannot be sufficiently enhanced. When only silica having a small particle size is used, the viscosity of the electrolytic solution becomes high and the liquid injection property of the electrolytic solution becomes poor. Further, if the particle size exceeds 300 nm, it becomes difficult for silica to gel. As silica,
Colloidal silica may be used or silica powder may be used. Colloidal silica is a colloidal dispersion of negatively charged amorphous silica particles dispersed in water.

[0006]

When the silica according to the present invention is used, silica particles 1 having a small particle size of 4 to 6 nm as shown in FIG.
... enter between the silica particles 2 having a large particle diameter of 40 to 300 nm. Therefore, small particle size silica 1
Plays a role of promoting the rolling of the silica 2 having a large particle size, and the thixotropic property of the gelled electrolytic solution (the viscosity of the electrolytic solution becomes low when the electrolytic solution is stirred, and the viscosity of the electrolytic solution when the electrolytic solution is stopped). Is higher). The inventor has found that 10 to 50% by weight has a particle size of 4 to 6 nm, and the balance contains silica having a particle size of 40 to 300 nm in an electrolytic solution to obtain optimum thixotropic properties. It was When such an electrolytic solution containing silica is used, the electrolytic solution can be easily injected by pouring the electrolytic solution into the battery case while stirring. After the liquid is poured into the battery case, the viscosity becomes high enough to prevent the electrolytic solution, so that the life of the sealed lead-acid battery can be extended.

[0007]

EXAMPLES The sealed lead-acid battery used in the tests including this example was made as follows. First, an electrolytic solution holder (retainer) having a porosity of 90% and a thickness of 1.8 mm was prepared using glass fibers having an average wire diameter of 1 μm. The preferable average diameter of the electrolytic solution holder is 0.5 to 2 μm, and the preferable porosity is 85 to
93%, preferable thickness is 1.0 to 2.5 mm. Next, three well-known paste type positive electrode plates and four well-known paste type negative electrode plates were laminated via an electrolytic solution holder to form an electrode plate group, and this electrode plate group was placed in a battery case. Next, silica having a particle size of 4 to 6 nm and a particle size of 40 to 300 n with different mixing ratios (% by weight) are used.
A plurality of electrolytic solutions were prepared by adding 1,3,5 and 5% by weight of silica of m to dilute sulfuric acid having a specific gravity of 1.30 (20 ° C.), respectively. Silica was added by putting a colloidal solution containing silica in the electrolytic solution. Figure 1 shows a particle size of 4
5 shows the relationship between the mixing ratio of silica having a size of ˜6 nm with respect to the whole silica and the thixotropy index of the electrolytic solution. In addition,
In each curve in the figure, the amount of silica added to the electrolytic solution is different. From this figure, it is understood that the thixotropy index of the electrolytic solution becomes maximum when the mixing ratio of silica having a particle size of 4 to 6 nm is 10 to 50% by weight, regardless of the amount of silica added to the electrolytic solution. The thixotropic index is
It was determined by the formula (viscosity value at 10 rpm) / (viscosity value at 100 rpm).

Next, the prepared electrolytic solution was poured into a battery container while stirring at 100 rpm by a mixer, and the electrolytic solution was impregnated with the electrolytic solution holding body to obtain 38Ah-12.
Each sealed lead acid battery of V was made. The preferred stirring speed is 1
It is from 00 to 500 rpm. After discharging each battery with a constant current of 9.5 A (cutoff voltage 10.2 V), 14.
The charge / discharge cycle of charging for 8 hours at a constant current and constant voltage of 7 V (limit current: 7.6 A) was repeated to measure the number of cycles until each battery reached the end of its life (capacity that is less than 50% of the rated capacity). Then, the relationship between the mixing ratio of silica having a particle diameter of 4 to 6 nm to the whole silica and the number of cycles leading to the life of the battery was investigated. FIG. 2 shows the measurement result. From this figure, it is understood that the cycle number to reach the maximum is maximized when the mixing ratio of silica having a particle size of 4 to 6 nm is 10 to 50% by weight, regardless of the amount of silica added to the electrolytic solution. From this, it can be seen that the cycle life shows the same tendency as the thixotropic index of the electrolytic solution shown in FIG.

Although colloidal silica is added to the electrolytic solution in this embodiment, powdered silica may be added to the electrolytic solution. When the silica powder is added to the electrolytic solution, the silica powder is placed in a mortar and ground with a pestle, so-called kneading, so that the silica powder has a predetermined particle size and is added to the electrolytic solution.

The structure of some of the inventions described in the specification will be shown below.

(1) An electrode plate group in which a paste type positive electrode plate and a paste negative type electrode plate are laminated via a retainer is arranged in a battery case, and an electrolytic solution made of dilute sulfuric acid containing silica is placed in the battery container. In the method for producing a sealed lead-acid battery by injecting into the interior, 10 to 50% by weight of the silica has a particle diameter of 4 to 6 nm, and the rest has a particle diameter of 40 to 300 nm. A method for manufacturing a sealed lead-acid battery, comprising pouring the electrolytic solution into the battery case while stirring the electrolytic solution at 100 to 500 rpm.

(2) The retainer has an average wire diameter of 0.
Porosity 85-93% using glass fiber of 5-2 μm,
A method for producing a sealed lead-acid battery, characterized in that a thickness of 1.0 to 2.5 mm is used.

[0013]

According to the present invention, the optimum thixotropic property of the electrolytic solution can be obtained. Therefore, it becomes easy to inject the electrolytic solution into the battery case, and the viscosity of the electrolytic solution becomes high enough to prevent stratification, so that the life of the sealed lead-acid battery can be extended.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a mixing ratio of silica having a particle diameter of 4 to 6 nm with respect to the whole silica and a thixotropic index of an electrolytic solution.

FIG. 2 is a diagram showing a relationship between a mixing ratio of silica having a particle diameter of 4 to 6 nm with respect to the entire silica and the number of cycles leading to the life of the battery.

FIG. 3 is a diagram showing silica used in the sealed lead-acid battery of the present invention.

[Explanation of symbols]

 1,2 silica particles

Claims (1)

[Claims] 1. In a sealed lead-acid battery using a retainer impregnated with an electrolyte solution containing silica, 10 to 50% by weight of silica contained in the electrolyte solution is 4 to 4.
It has a particle diameter of 6 nm, and the balance is 40 to 30.
A sealed lead-acid battery having a particle size of 0 nm.