JPH0729610A - Charging method for lead-acid battery - Google Patents

Abstract

PURPOSE:To provide a method for electric charging, capable of remarkably enhancing lifetime performance of a battery using a lead alloy grid not including antimony. CONSTITUTION:In a method for electrical charging a lead-acid battery using a lead alloy grid not including antimony, electric charging is completed within a charging time expressed by T<=t+2, wherein t(mm) represents a thickness of a positive electrode plate of the battery and T represents a time (charging time) from the beginning of the charging until the completion of the charging.

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, and the capacity is quickly reduced. The tendency is remarkable especially in high-performance batteries using thin plates. Therefore, in applications requiring a long life, the electrode plate having a considerably large thickness compared with the battery using the antimony alloy has to be used, 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, which are less likely to form a passive layer 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 gist is to select a charging time suitable for the thickness of the positive electrode plate of the battery. Specifically, the thickness of the positive electrode plate of the battery to be charged is tmm, and the charging time is T
The charging is performed within the charging time represented by T ≦ t + 2.

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. Sato
The time during which the lattice interface is exposed to a high potential, that is, the charging time, has the greatest effect, and in a battery using a positive electrode plate with a certain electrode plate thickness, it becomes reactive when exposed to a high potential for a certain time or longer. It was found that a rich corrosion layer was formed.

Based on the results of this research, the present invention has studied the charging conditions for preventing the formation of a highly reactive corrosion layer in detail in relation to the thickness of the positive electrode plate 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 having a thickness of 3 mm (t = 3) in which a lead-0.1% calcium alloy lattice is filled with an active material are alternately laminated with a fine glass fiber separator interposed therebetween, and an electrode plate group is formed. To absorb and retain sulfuric acid with a specific gravity of 1.32.
A sealed lead acid battery of V-6Ah 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 ≦ t + 2 = 5) according to the present invention, the charging time (T) was set to 3, 4, 5 hours, and as a comparative example, the charging time (T) was set to 6, 8, 10 hours. FIG. 1 shows the result of the test performed for the case. 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 for more than 5 hours, the capacity decrease becomes more severe as the charging time is lengthened. Recognize.

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 the battery using the same positive electrode plate having a thickness of 3 mm as in Examples 1 and 2. The charging method was a constant current-constant voltage method, and the charging conditions were set so that all were almost fully charged. The test results are shown in FIG.

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 when the charging time is within 5 hours, a good capacity transition is exhibited. (Example 5) Further, the thickness is 1 mm, 2 mm, and 4 mm.
A battery was manufactured using a positive electrode plate of (t = 1, 2, 4), 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 can be seen from the test results, when the thickness of the positive electrode plate of the battery is tmm and the charging time is T time, T ≦ 3 when t = 1, T ≦ 4 when t = 2, and t = 3. When T ≦ 5,
When charging is performed under the condition of T ≦ 6 when t = 4, that is, t + 2 when charging a battery using a positive electrode plate having a thickness of Tmm.
It can be seen that if the battery is charged within the time, 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.

[0018]

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 thicknesses.

Claims (1)

[Claims] 1. A method for charging a lead storage battery using a lead alloy grid containing no antimony, wherein the thickness of the positive electrode plate of the battery to be charged is tmm, and the time from the start of charging to the end of charging (charging time) is T. A charging method for a lead storage battery, characterized in that charging is completed within a charging time represented by T ≦ t + 2.