JPH0794205A - 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 to limit the utilization efficiency of the positive pole plate and suppress the cycle life deterioration due to softening the positive pole active material and at the same time the amount of an electrolytic liquid to be contained in a separator is set to be 3.5-4.5cc per 1g of the separator. A sealed type lead-acid battery with excellent properties to accept charging at rated voltage and useful for cyclic use is obtained by efficiently utilizing the gas absorbing reaction occuring in the battery system and forcedly charging the positive pole plate.

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 limiting the absolute amount of sulfuric acid in the battery system to within a certain range to suppress the softening of the positive electrode active material, and by setting the amount of electrolyte contained in the separator within a certain range, the gas absorption reaction that occurs in the battery system can be prevented. It is used efficiently to improve the acceptability of constant voltage charging and, in turn, the cycle life characteristics.

[0004]

In order to achieve this object, the sealed lead-acid battery of the present invention has an absolute amount of sulfuric acid in the battery system of 0.30 to 0.
The amount of the electrolytic solution contained in the separator is set to 3.5 to 4.5 per 1 g of the separator while being set within the range of 45 g.
It is set within the range of cc.

[0005]

[Operation] The softening of the positive electrode active material is suppressed by limiting the absolute sulfuric acid amount and the utilization rate of the positive electrode plate at the time of complete discharge, and the separator is interposed by limiting the amount of the electrolytic solution contained in the separator. By utilizing the above gas absorption reaction, the positive electrode plate is forcibly charged to improve the charge acceptability, and the acceptability at the time of constant voltage charging and eventually the cycle life characteristics are improved.

[0006]

EXAMPLES Examples of the present invention will be described below.

Under the conditions shown in Table 1, voltage 12V and capacity 3
Ten types of 8 Ah (20 HR) type batteries A to J were prototyped, and an initial capacity test and a cycle life test were performed on these prototype batteries. Each prototype battery had a structure of 3 positive plates and 4 negative plates, and a glass mat separator was used.
All other conditions such as the positive electrode active material ratio were the same.

[0008]

[Table 1]

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

From FIG. 1, initial capacity test (23 HR discharge)
Trial batteries having a capacity of 20 hours or more in B to J
And the absolute amount of sulfuric acid is 0.30 g per 1 g of the positive electrode active material.
It can be seen that the battery is set as above. In addition, in order to improve the cycle characteristics like the prototype battery A, 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, it is understood that the prototype batteries having excellent cycle life characteristics are A to E, G and H, and the absolute sulfuric acid amount is set to 0.45 g or less per 1 g of the positive electrode active material. 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 initial capacity test (23 HR discharge) has a capacity of 20 hours or more,
It is also understood that the range of absolute sulfuric acid amount, which is excellent in cycle life characteristics, is 0.30 to 0.45 g per 1 g of the positive electrode active material.

FIG. 3 shows the relationship between the initial capacity test result of the prototype battery and the internal resistance value of the battery when the discharge condition at 25 ° C. is the final voltage of 9.6 V and 1 CA discharge.

From FIG. 3, even if the absolute sulfuric acid amount is set within the range of 0.30 to 0.45 g per 1 g of the positive electrode active material as in the prototype batteries C and G, the amount of the electrolytic solution in the separator is 3. It can be seen that if it is less than 5 cc, the internal resistance value increases and the initial capacity decreases.

FIG. 4 is included in the separator of the prototype battery at 25 ° C. when the charging conditions are maximum 0.4 CA charge and 14.7 V × 12 H, and discharge conditions are final voltage 9.6 V and 1 CA discharge. It shows the relationship between the amount of electrolyte and cycle life characteristics. The life was judged by 70% of the initial capacity.

As shown in FIG. 4, even when the absolute sulfuric acid amount is set within the range of 0.30 to 0.45 g per 1 g of the positive electrode active material as in the prototype batteries F and I, the amount of the electrolytic solution in the separator is 4. It can be seen that the cycle life is shortened when the amount exceeds 5 g. This is considered to be due to a decrease in current value due to the gas absorption reaction on the negative electrode plate with the separator interposed therebetween being alienated to the liquid layer when the amount of the electrolytic solution in the separator is large at the end of charging.

From the results shown in FIGS. 3 and 4, the range of the amount of electrolytic solution in the separator of the prototype battery having a sufficient initial capacity and excellent cycle life characteristics is 3.5 to 4.5 cc. I understand.

From the above results, the absolute amount of sulfuric acid in the battery system is 0.30 to 0.4 per 1 g of the positive electrode active material in a fully charged state.
By setting the amount of the electrolytic solution contained in the separator within the range of 3.5 to 4.5 cc per 1 g of the separator, the cycle characteristics can be improved while maintaining the initial capacity. Recognize.

[0020]

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 battery cycle life test results and the absolute amount of sulfuric acid in the battery system.

FIG. 3 is a characteristic diagram showing the relationship between the initial capacity test result of the battery and the internal resistance value of the battery.

FIG. 4 is a characteristic diagram showing the relationship between the amount of electrolyte contained in a separator and cycle life characteristics.

Claims (1)

[Claims] 1. The absolute amount of sulfuric acid in the battery system is set within the range of 0.30 to 0.45 g per 1 g of the positively charged active material in a fully charged state, and the amount of electrolytic solution contained in the separator is 3 per 1 g of the separator. Sealed lead acid battery set within the range of 0.5 to 4.5 cc.