JPH0845552A - 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, by selecting a charging time suitable for the positive electrode active material density of the battery. CONSTITUTION:A lead-acid battery using a lead alloy grid including no antimony actually is charged as follows: When the positive electrode active material density of a battery to be charged is made rho (g/cm<3>), and the time from the starting to the finishing of the charging (the charge time) is made T (h), the charging is completed within the charge 1 time shown in the formula T<=5rho-13.5. By such a charging method, the charging is completed before a corrosive layer having a high reactivity is formed, and as a result, the generation of a passive state layer can be prevented, and the service life property of the battery can be improved extensively.

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 particularly in a high-performance battery using a positive electrode plate having a low active material density. Therefore, in applications where a long life is required, there is no choice but to use an electrode plate having a considerably higher active material density than a battery using an antimony alloy, and there is a problem that the weight energy density becomes small.

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 gist is to select a charging time suitable for the density of the positive electrode active material of the battery. Specifically, charging is performed within the charging time represented by T ≦ 5ρ−13.5, where ρ is the positive electrode active material density of the battery to be charged and T is the charging time.

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 and current density at the lattice interface. The positive electrode active material density and the time during which the lattice interface is exposed to a high potential, that is, the charging time, have a large effect, and a battery using a positive electrode plate with a certain active material density is exposed to a high potential for a certain period or longer. It was found that a corrosive layer with high reactivity 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 density of the positive electrode active material, 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 lead-0.1% calcium alloy lattice with an active material density of 3.7 g / cm ³ (ρ = 3.7) in a fully charged state.
The positive electrode plate filled with the active material and the negative electrode plate are alternately laminated via the fine glass fiber separator to form an electrode plate group, which absorbs and holds sulfuric acid to prepare a 2V-6Ah sealed lead-acid battery. did.

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 ≦ 5ρ−13.5 = 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, 8 The results of the tests conducted for 10 hours are shown in FIG. As is clear from this result, the charging method according to the present invention, that is, the charging time is 5
It can be seen that when the charging time is within the time, the capacity changes favorably, but when the charging is performed for more than 5 hours, the capacity decrease becomes more severe as the charging time is lengthened.

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 Same active material density as in Examples 1 and 2.
Using a battery using a positive electrode plate of 7 g / cm ³ , the same cycle life test was performed under charging conditions with different current and time.
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 the capacity transition is excellent when the charging time is within 5 hours. (Example 5) Further, the active material density is 3.3 g / cm ³ ,
3.5 g / cm ³ , 3.9 g / cm ³ (t = 3.3, ³ .
A battery was manufactured using the positive electrode plate of No. 5, 3.9), 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 battery positive electrode active material density is ρg / cm ³ and the charging time is T hours, ρ
= 3.3 when T ≦ 3, when t = 3.5 T ≦ 4, t =
When the battery is charged under the conditions of T ≦ 5 when 3.7 and T ≦ 6 when t = 3.9, that is, when a battery using a positive electrode plate having an active material density ρg / cm ³ is charged (5ρ− It can be seen that the life performance is significantly improved if the battery is charged within 13.5) hours.

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 active material densities.

Claims (1)

[Claims] 1. A method for charging a lead storage battery using a lead alloy lattice substantially free of antimony, wherein the density of the positive electrode active material of the battery to be charged is ρ (g / cm ³ ), from the start of charging to the end of charging. Up to (charge time) T (hours),
A charging method for a lead storage battery, characterized in that charging is completed within a charging time represented by T ≦ 5ρ−13.5.