JPH08195217A - Sealed lead-acid battery - Google Patents

Abstract

PURPOSE: To provide a sealed lead-acid battery which simultaneously achieves the enhancement of its discharge capacity and of its constant-voltage charge cycle characteristic. CONSTITUTION: The amount of electrolyte in a battery system is 0.65ml or more per 1g of a fully charged positive active material, and a negative plate is made water-repellent for 2% or more and 10% or less of its surface area. Preferably the side of the negative plate which does not face the positive plate is selectively made water-repellent so as to provide a sealed lead-acid battery having a high capacity and an excellent cycle characteristic.

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 A sealed lead acid battery is constructed by inserting a positive electrode plate, a negative electrode plate, and a plurality of separators, each of which is stacked in a cell chamber. Conventionally, in a sealed lead-acid battery, the amount of electrolyte is regulated, and the electrode plate / separator is impregnated with a necessary amount of liquid within a range where liquid leakage does not occur. Therefore, in order to improve the battery capacity, it is necessary to sufficiently diffuse the electrolytic solution, and especially in the case of high rate discharge, it is improved by increasing the amount of the electrolytic solution contained in the positive and negative electrode plates to facilitate diffusion. It was clear.

[0003]

On the other hand, in constant voltage charging, the reaction of absorbing oxygen gas generated at the end of charging in the negative electrode was utilized to forcibly and completely charge the positive electrode plate. Therefore, it is necessary to make the electrolytic solution in the negative electrode plate relatively sparse so that gas absorption is actively performed.

As described above, a large amount of electrolytic solution is required to improve the battery discharge capacity, and conversely, it is necessary to reduce the amount of electrolytic solution to improve the constant voltage charging characteristics. In particular, since the constant voltage charging characteristics influence the cycle life characteristics of the battery, compatibility of these is extremely important in the battery characteristics.

As described above, improving the battery capacity and improving the constant voltage charging cycle characteristic are contradictory technologies, and the present invention solves these two problems at the same time.

[0006]

In order to solve these problems, the present invention sets the amount of electrolytic solution in a battery system to 0.65 ml or more per 1 g of a fully charged positive electrode active material, and Water repellent treatment is applied to 2% or more and 10% or less of the surface area. Furthermore, by applying water repellent treatment to the negative electrode plate selectively to the negative electrode plate surface that does not face the positive electrode plate,
It is intended to realize a sealed lead-acid battery with high capacity and excellent cycle life characteristics.

[0007]

The function of the sealed lead-acid battery is how to apply the electrolytic solution to the battery system, and the discharge capacity is determined by the amount of the electrolytic solution. In order to improve the cycle life characteristics, the potential of the negative electrode plate is shifted to a noble level by utilizing the reaction of absorbing oxygen gas generated at the end of charging in the negative electrode, and as a result, the positive electrode plate is charged by constant voltage charging. It is necessary to force a full charge.

Therefore, in the present invention, while ensuring a sufficient amount of the electrolytic solution in the cell chamber, a part of the negative electrode plate is subjected to a water repellent treatment to make the distribution of the electrolytic solution in a part of the negative electrode plate sparse, so that a gas absorption reaction is achieved. Is to promote. As a result, the constant voltage charge acceptance of the cell, that is, the charging efficiency is improved. However, the water-repellent treatment hinders the diffusion of the electrolytic solution into the negative electrode plate during discharge, and when the amount of the electrolytic solution in the negative electrode plate is reduced and the electrolytic solution is not sufficiently diffused, the utilization rate of the negative electrode and In order to reduce the discharge capacity, it is necessary to limit the area or place of the water repellent treatment.

That is, preferably, the surface of the negative electrode that does not face the positive electrode plate is selectively subjected to a water repellent treatment.

[0010]

EXAMPLES The present invention will be described in detail below with reference to examples.

Nominal voltage and capacity is 12V24Ah (20H
R) type sealed lead acid battery, the amount of electrolyte shown in Table 1,
Conventional Examples 1 to 3 and Batteries A to E of the present invention under water repellent treatment conditions
8 types in total were manufactured, and a discharge capacity test and a cycle life test were conducted respectively. The amount of the electrolytic solution is an amount per 1 g of the positive electrode active material in a fully charged state, and the water repellent treatment of the negative electrode plate is performed by dispersing fluorocarbon resin powder in a specified area to 270 to 270.
It heat-processed at 300 degreeC. The discharge capacities of the batteries were all controlled by the positive electrode.

[0012]

[Table 1]

From FIG. 1, the discharge capacity of the battery is dominated by the amount of the electrolytic solution, and in order to realize a high capacity, an amount of the electrolytic solution of 0.65 ml or more per 1 g of the positive electrode active material is required, and the area of the water repellent treatment is large. It is clear that when the surface area of the negative electrode plate exceeds 10%, the capacity is significantly reduced.

Further, it is clear from FIG. 2 that the cycle characteristics have no effect unless the water repellent treated area is 2% or more. Analysis of the causes of early deterioration of Conventional Examples 1 and 3 and Battery A after completion of the cycle life test revealed that the capacity was deteriorated due to insufficient charging.

Next, the nominal voltage / capacity is 12V24Ah (2
A total of five (0HR) type batteries were produced under the conditions shown in Table 2 from batteries F to J, and a discharge capacity test similar to the above was carried out. The water repellent treatment of the negative electrode plate was performed only on the surface not facing the positive electrode plate, and the same water repellent treatment was performed for comparison.

[0016]

[Table 2]

From FIG. 3, the rate at which the electrolytic solution diffusion to the negative electrode plate is hindered at the time of discharge by the water repellent treatment and the capacity is reduced is smaller when the water repellent treatment is applied only to the surface not facing the positive electrode plate. I understand.

Further, it can be seen from FIG. 2 that the effect of the water repellent treatment on the cycle characteristics is the same even if it is limited to the surface not facing the positive electrode plate.

[0019]

As described above, the present invention can improve the discharge capacity of a sealed lead-acid battery and at the same time improve the cycle life characteristics.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the amount of electrolyte solution per 1 g of a positive electrode active material and the discharge capacity.

FIG. 2 is a diagram showing a relationship between a water repellent treated area of a negative electrode plate and cycle life.

FIG. 3 is a diagram showing a relationship between a water repellent treated area of a negative electrode plate and a discharge capacity.

Claims (2)

[Claims] 1. A seal, wherein the amount of electrolyte in a battery system is 0.65 ml or more per 1 g of a positively charged positive electrode active material, and the negative electrode plate is water-repellent at 2% or more and 10% or less of its surface area. Type lead acid battery. 2. The sealed lead acid battery according to claim 1, wherein the negative electrode plate is selectively subjected to a water repellent treatment on a surface which does not face the positive electrode plate.