JPH0794204A - Sealed type lead-acid battery - Google Patents

Abstract

PURPOSE:To solve problems of charging properties and provide a sealed type lead-acid battery for cyclic use with improved properties to accept charging at rated voltage. CONSTITUTION:The absolute amount of sulfuric acid in a sealed type lead-acid battery is set to be within 0.30-0.45g per 1g of a positive pole active material in completely charged state and at the same time the amount of an electrolytic liquid is set to be 0. 65cc or less per 1g of the positive pole active material in the completely charged state, so that the positive pole plate is forcedly charged and the property to accept charging is improved while utilizing the gas absorption reaction occuring in the battery system by limiting the utilization efficiency of the positive pole plate at the time of complete discharging. As a result, a sealed type lead-acid battery with excellent properties to accept charging at rated voltage and improved cycle properties is obtained.

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 Conventionally, sealed lead-acid batteries are maintenance-free and have a convenient design without the need to replenish water. However, when used in cycle applications, when the battery is charged at a constant current, the electrolyte solution decreases sharply. Shorten the life.
Also, in constant voltage charging, shortage of charge is likely to occur and cycle life is shortened.

[0003]

SUMMARY OF THE INVENTION The present invention aims to improve the cycle life of a sealed lead acid battery,
By setting the absolute amount of sulfuric acid and the amount of electrolytic solution in the battery system within a certain range, softening of the positive electrode active material is suppressed and the acceptability of constant voltage charging is improved.

[0004]

To achieve this object, in the sealed lead-acid battery of the present invention, the absolute amount of sulfuric acid is set within the range of 0.30 to 0.45 g per 1 g of the positive electrode active material in a fully charged state. In addition, the amount of the electrolytic solution is set to 0.65 cc or less per 1 g of the positive electrode active material in a fully charged state.

[0005]

[Function] By limiting the absolute amount of sulfuric acid in the battery system to a certain range, the utilization factor of the positive electrode plate at the time of complete discharge is limited, the cycle life deterioration due to the softening of the positive electrode active material is suppressed, and the amount of electrolyte solution The positive electrode plate is forcibly charged by utilizing the gas absorption reaction which is limited and occurs in the battery system to improve the charge acceptability. As a result, it is possible to improve the battery life under the conditions close to the actual cycle use condition in the market.

[0006]

EXAMPLES Examples of the present invention will be described below.

Under the conditions shown in Table 1, voltage 12V and capacity 3
Nine types of 8Ah (20HR) type batteries A to I were prototyped, and an initial capacity test and a cycle life test were performed on these prototype batteries. Each prototype battery was composed of three positive electrode plates / four negative electrode plates, and all other conditions such as the ratio of negative / positive electrode active material were the same.

[0008]

[Table 1]

FIG. 1 shows a discharge condition of 0.0 at 25 ° C.
5 shows the relationship between the initial capacity test result of the prototype battery and the absolute amount of sulfuric acid in the battery system in the case of 5 CA.

From FIG. 1, the prototype battery having a capacity of 20 hours or more in the initial capacity test (230 HR discharge) is C
I, the absolute amount of sulfuric acid is 0.3 per 1 g of the positive electrode active material.
It can be seen that the battery is set to 0 g or more. In addition, in order to improve the cycle characteristics like the prototype batteries A and B,
A battery in which the absolute amount of sulfuric acid is set to less than 0.30 g per 1 g of the positive electrode active material cannot obtain a sufficient initial capacity.

FIG. 2 shows that at 25 ° C., the maximum charging conditions are 0.4 CA charge and 14.7 V × 12 H, and the discharging conditions are final voltage 10.5 V and 0.25 CA discharge.
It shows the relationship between the cycle life test results of the prototype battery and the absolute amount of sulfuric acid in the battery system. The life was judged by 70% of the initial capacity.

From FIG. 2, the prototype batteries having excellent cycle life characteristics are A to G, and the absolute amount of sulfuric acid is 1 g of the positive electrode active material.
It can be seen that the battery is set to 0.45 g or less per unit. The difference in the cycle characteristics is due to the change in the utilization factor (depth of discharge) of the positive electrode plate due to the difference in the absolute sulfuric acid amount.

From the results of FIGS. 1 and 2, the range of absolute sulfuric acid amount having a capacity of 20 hours or more in the initial capacity test (230 HR discharge) and excellent cycle life characteristics is 0. It can be seen that the amount is 30 to 0.45 g.

Further, FIG. 3 shows the cycle life of the prototype battery at 25 ° C. when the charging conditions are 0.4 CA maximum charge, 14.7 V × 12 H maximum, and the discharge conditions are final voltage 10.5 V and 0.25 CA discharge. 9 shows changes in battery capacity in a test.

FIG. 4 shows that at 25 ° C., the maximum charging conditions are 0.4 CA charge and 14.7 V × 12 H, and the discharging conditions are final voltage 10.5 V and 0.25 CA discharge.
FIG. 3 shows the relationship between the ratio of the amount of charged electricity to the amount of discharged electricity and the amount of electrolyte in the initial cycle life test of the prototype battery.

As shown in FIGS. 3 and 4, the absolute amount of sulfuric acid was 0.30 to 0.45 g per 1 g of the positive electrode active material as in the case of the prototype battery H.
If the amount of electrolytic solution is more than 0.65 cc even if it is set within the range of 1, the current value extremely decreases at the end of charging, the constant voltage charge acceptability deteriorates, the charging becomes insufficient, and the cycle life becomes short. It is considered that this is because the gas absorption reaction at the negative electrode plate is alienated to the liquid layer and the reaction does not occur when the amount of the electrolytic solution is large at the end of charging, so that the current value decreases. Therefore, it is desirable to set the amount of the electrolytic solution to 0.65 cc or less per 1 g of the positive electrode active material.

From the above results, by setting the absolute amount of sulfuric acid and the amount of electrolytic solution within a certain range, it is possible to solve each of the problems as in the prior art at the same time.

[0018]

As described above, according to the present invention, the cycle life characteristics can be improved in a state closer to the actual operating conditions in the market while maintaining an appropriate initial capacity.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing the relationship between the initial capacity test result of a battery and the absolute amount of sulfuric acid in the battery system.

FIG. 2 is a characteristic diagram showing the relationship between the cycle life test result and the absolute amount of sulfuric acid in the battery system.

FIG. 3 is a characteristic diagram showing a change in battery capacity in a cycle life test.

FIG. 4 is a characteristic diagram showing the relationship between the ratio of the amount of charged electricity to the amount of discharged electricity and the amount of liquid at the beginning of the cycle life test.

Claims (1)

[Claims] 1. The absolute sulfuric acid amount is set within a range of 0.30 to 0.45 g per 1 g of the positive electrode active material in the fully charged state, and the amount of electrolytic solution is 0.65 cc or less per 1 g of the positive electrode active material in the fully charged state. Sealed lead acid battery set to.