JPH0845551A - Charging method of lead-acid battery - Google Patents

Abstract

PURPOSE:To prevent the generation of a passive state layer at the interface of a positive electrode grid including no antimony, and to improve the service life property of a battery extensively, by selecting a charging time suitable for the electrolyte amount of the battery. CONSTITUTION:A lead-acid battery using a lead alloy grid including no antimony actually is charged as follows: When the ratio V/P of the electrolyte amount V (cc) of a battery to be charged, and the amount of a positive electrode active material P (g), is made beta, and the time from the starting to the finishing of the charge (the charge time) is made T (h), the charge is finished within the charge time shown in the formula T<=10.25 to 7.5beta. By such a charging method, the charging is finished before a corrosive layer having a high reactivity is formed, and as a result, the generation of a passive state layer is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for charging a lead storage battery using a lead alloy grid containing no antimony, and more particularly to a method for charging a battery used by alternately charging and discharging.

[0002]

2. Description of the Related Art Conventionally, lead-antimony alloys have been mainly used for the electrode plate grids of lead-acid batteries, but so-called maintenance-free type lead-acid batteries that do not require maintenance such as replenishing water are To prevent loss of liquid water, lead alloys that do not contain antimony, such as lead-calcium alloys, are commonly used.

However, in a battery using this type of alloy, when deep charge and discharge are repeated, a passivation layer of lead sulfate is formed at the interface between the lattice of the positive electrode plate and the active material during discharge, so that the capacity is early. The tendency is remarkable especially in a high-performance battery in which the amount of the electrolytic solution is large relative to the amount of the positive electrode active material. Therefore, in applications requiring a long life, the electrolyte performance-the positive electrode active material weight ratio has to be made considerably smaller than that of a battery using an antimony alloy, and the discharge performance has to be sacrificed.

As a means for preventing such an early capacity decrease, various alloy compositions other than antimony alloys have been conventionally studied, in which a passivation layer is not easily formed at the interface between the lattice and the active material. , Alloys comparable to antimony alloys have not yet been developed, and short-lived problems have not been overcome.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies as to a method for preventing the formation of a passive layer at the interface of a positive electrode lattice containing no antimony, and as a result, have improved the lattice alloy composition which has been studied conventionally. However, it has been found that by optimizing the conditions under which the grid is subjected to corrosion, that is, by optimizing the charging method, the formation of the passivation layer can be prevented and the life performance of the battery can be significantly improved. Reached The point is to select a charging time suitable for the amount of electrolyte in the battery. Specifically, the electrolytic solution amount of the battery to be charged-the positive electrode active material weight ratio is β,
The charging time is defined as T time, and charging is performed within the charging time represented by T ≦ 10.25-7.5β.

The reason why the lead sulfate passivation layer is formed at the interface between the active material and the grid of the positive electrode plate using the lead alloy grid containing no antimony is that the grid corrosion layer is more reactive than the active material. This is because the corrosion layer is discharged before the active material is sufficiently discharged during discharging. On the other hand, the corrosion layer of the antimony alloy lattice is more resistant to discharge and more stable than the active material. It is considered that such a difference in reactivity of the corrosion layer is caused by a difference in the composition and structure of the corrosion layer.

The composition and structure of the corrosion layer differ depending on the composition and crystal structure of the alloy. In addition to this, the conditions such as the potential at the lattice interface, the current density, the hydrogen ion concentration (pH), etc. under which the lattice is exposed to corrosion and However, it also greatly changes depending on the electrochemical conditions such as the time it is exposed to the corrosive conditions.

The inventors of the present invention have paid attention to the conditions under which such a corrosion layer is formed, and as a result of repeated research, the reactivity of the corrosion layer is closely related to the pH of the lattice interface. When,
The time during which the lattice interface is exposed to a high potential, that is, the charging time, has a large effect, and in a battery with a certain electrolytic solution amount-positive electrode active material weight ratio, when exposed to a high potential for a certain period of time or more, the reactivity becomes It was found that a rich corrosion layer was formed.

Based on the results of this research, the present invention has investigated the charging conditions for preventing the formation of a highly reactive corrosion layer in detail in relation to the amount of electrolytic solution and found the optimum value. By using the charging method according to the present invention to terminate charging before the formation of a highly reactive corrosion layer, it is possible to prevent the formation of the passivation layer and significantly improve the life performance of the battery. Become. The details will be described below using examples.

[0010]

【Example】

(Example 1) A positive electrode plate and a negative electrode plate in which a lead-0.1% calcium alloy lattice was filled with an active material were alternately laminated with a fine glass fiber separator interposed therebetween to form an electrode plate group. , The ratio of the amount of the electrolyte solution to the weight of the positive electrode active material is 0.7 (β =
Sulfuric acid is absorbed and held so that
A 6 Ah sealed lead acid battery was produced.

Using this battery, a charge / discharge cycle life test was conducted at room temperature (25 ° C.) under various charging conditions. The discharge was performed up to 1.65 V at 2 A, and the charge was performed by a constant current-constant voltage system (3 A-2.4 V). As an example of the charging method (T ≦ 10.25-7.5β = 5) according to the present invention, when the charging time (T) is set to 3, 4, 5 hours, and as a comparative example, the charging time (T) is 6 The results of the tests conducted for 8 hours and 10 hours are shown in FIG. As is clear from this result, when the charging method according to the present invention, that is, when the charging time is within 5 hours, a good capacity transition is shown, but when the charging is performed over 5 hours, the charging time is lengthened. It can be seen that the capacity decreases more severely.

In order to clarify the cause of the capacity decrease, when the battery charged for more than 5 hours reached a capacity of 50% of the initial capacity, the battery was disassembled and investigated, and the interface between the grid of the positive electrode plate and the active material was found. It was confirmed that a passivation layer was formed on the. Further, regarding the battery having the charging time of 5 hours or less, the battery was disassembled and examined at the time of 500 cycles, but formation of the passivation layer was not observed.

Regarding the charging time of 3 hours, the capacity has been relatively low from the beginning, which means that the battery is not fully charged. If necessary, supplementary charging is required. If this is done, the capacity will be restored, and there is no particular problem in terms of life performance. (Example 2) The same test as in Example 1 was conducted with a charging voltage of 2.5.
It was carried out also in the case of V and 2.3V. FIG. 2 shows the result when the charging voltage was 2.5 V, and FIG. 3 shows the result when the charging voltage was 2.3 V. As is clear from this result, at any charging voltage, a good capacity transition is shown when the charging time (T) is within 5 hours, but the charging time is exceeded when charging is performed for more than 5 hours. It can be seen that the longer the value is, the more the capacity decreases. (Example 3) The same cycle life test was performed under the charging conditions in which the current and the time were changed, using a battery having the same electrolyte solution amount-positive electrode active material weight ratio of 0.7 as in Examples 1 and 2. In addition,
The charging method was a constant current-constant voltage method, and the charging conditions were set so that both were almost fully charged. Figure 4 shows the test results
Shown in

In FIG. 4, a indicates a charging condition of 10 A.
-2.4V for 2 hours, b is 5A-2.4V for 3 hours, c
Is 3A-2.4V for 4 hours, d is 2A-2.4V for 5 hours, e is 1.5A-2.4V for 6 hours, and f is 1A-2.
4V is 8 hours, and g is 0.8A-2.4V and 10 hours.

As is clear from these results, the life performance is greatly improved as the charging current is increased and the charging time is shortened, and particularly when the charging time is within 5 hours, a good capacity transition is exhibited. Recognize. (Example 4) The temperature conditions of the tests shown in Examples 1 to 3 were set to 1
The test results in the case of changing the temperature from 0 to 40 ° C. are collectively shown in FIG. 5 as the relationship between the charging time and the life cycle number. The number of life cycles here is 50 times the initial capacity.
It was the time when the percentage was cut off. As is clear from this result,
It can be seen that the cycle life performance is improved as the charging time is shortened, and particularly the capacity transition is excellent when the charging time is within 5 hours. (Example 5) Furthermore, the ratio of the amount of the electrolytic solution to the weight of the positive electrode active material is 0.5, 0.9, 1.1 (β = 0.5, 0.9, 1.
A battery was manufactured using the positive electrode plate of 1), and a cycle life test similar to the tests shown in Examples 1 to 4 was performed under various charging conditions. The test results are shown in FIG. 6 together with the results of Example 4. As is clear from the test results, if the ratio of the amount of electrolyte in the battery to the weight of the positive electrode active material is β and the charging time is T time, β =
When 1.1, T ≦ 2, when β = 0.9, T ≦ 3.5, β
= 0.7 when T = 5 and β = 0.5 when T ≤ 6.5, that is, when charging a battery in which the electrolyte ratio to the positive electrode active material weight ratio is β ( 10.25-7.5
It can be seen that if the battery is charged within β) hours, the life performance is significantly improved.

In the embodiment, the charging method is constant current-
The constant voltage method was used, but the constant current-constant voltage-constant current method,
Even when another charging method such as a stepwise constant current method or a quasi-constant voltage method is used, the same effect can be obtained by performing charging by the charging method according to the present invention.

[0017]

By using the charging method according to the present invention, the life performance of a battery using a lead alloy grid containing no antimony can be significantly improved. Further, according to the present invention, it is possible to use a high-performance battery which has been short-lived and has not been practically used in the past, and its industrial value is very large.

[Brief description of drawings]

FIG. 1 is a diagram showing a life test result of Example 1.

FIG. 2 is a diagram showing a life test result when the charging voltage is 2.5 V in Example 2.

FIG. 3 is a diagram showing a life test result when the charging voltage is 2.3 V in Example 2.

FIG. 4 is a diagram showing a life test result of Example 3;

FIG. 5 is a diagram showing a relationship between charging time and life cycle number.

FIG. 6 is a diagram showing the relationship between the charging time and the number of life cycles in electrode plates having different electrolyte solution-active material weight ratios.

Claims (1)

[Claims] 1. A method of charging a lead-acid battery using a lead alloy grid substantially free of antimony, which comprises the amount of electrolyte solution V (cc) and the amount of positive electrode active material P (g) of the battery to be charged. Assuming that the ratio V / P is β and the time (charging time) from the start of charging to the end of charging is T (hours), T ≦ 10.25-7.5β
A method of charging a lead storage battery, characterized in that charging is completed within the charging time represented by.