JPH0837029A - Method for charging lead-acid battery - Google Patents

Abstract

PURPOSE:To prolong the lifetime of a lead acid storage battery by completing the charge within the charging time expressed by T<=10-0.5D, where D in mm is the effective diameter of a positive electrode lattice machine and T is the time from the start of charging till its end. CONSTITUTION:Positive electrode plates prepared by fitting a lead-0.1% calcium alloy grating having the effective diameter 10mm (D=10) with an active material and negative electrode plates are laid one over another while glass fiber separators are interposed so that stacks of electrode plates are formed, where sulfuric acid is retained absorptively, and thus a sealed type lead acid storage battery is accomplished. Using this battery, comparison is made for the charging times 3, 4, 5, 6, 8, 10hr the charging method T<=10-0.5D=5. If the charging time is within 5hr, a good capacity transition is showed, but excess of 5hr exhibits steep drop of the capacity with longer charging time. In the battery with the charging time within 5hr, a decomposition investigation at the time with 500 cycles did not find any formation of passive state layer.

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 a battery using a positive electrode plate having coarse lattice bars. Therefore, in applications requiring a long life, it is necessary to use an electrode plate having a finer grid spacing as compared with a battery using an antimony alloy. However, when trying to make the spacing between the grids fine without changing the thickness of the grids, there is a problem that the grid weight becomes heavy and the weight energy density of the battery decreases.
Further, if the spacing between the lattice bars is made fine without changing the weight of the lattice, the lattice bars have to be made thin, and there is a problem that the elongation of the lattice becomes large and the life is shortened.

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 thereof is to select the charging time suitable for the roughness of the positive electrode grid of the battery, that is, the effective diameter. Here, the effective diameter is a value obtained by dividing the area of the portion surrounded by the center line of the positive electrode grid cross by one-fourth of the circumference length. For example, in the case of the grid shown in FIG. 7, [2ab /
(A + b)]. T ≦ 10, where Dmm is the effective diameter of the positive electrode grid of the battery to be charged and T is the charging time.
-To charge within the charging time represented by 0.5D.

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 present inventor has 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 has a lattice property that is closely related to the current density at the lattice interface. Effective diameter and time the grid interface is exposed to high potential,
That is, it has been found that the charging time has a great influence, and that in a battery using a positive electrode grid having a certain effective diameter, a corrosive layer rich in reactivity is formed when exposed to a high potential for a certain time or longer.

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 effective diameter of the positive electrode lattice, and has found the optimum value. is there. 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) Lead having an effective diameter of 10 mm (D = 10) -0.
A positive electrode plate and a negative electrode plate in which a 1% calcium alloy lattice is filled with an active material are alternately laminated through a fine glass fiber separator to form an electrode plate group, which absorbs and holds sulfuric acid to make it 2V-6.
A sealed lead acid battery of Ah 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 according to the present invention (T ≦ 10−0.5D = 5), when the charging time (T) was set to 3, 4, 5 hours, and as a comparative example, the charging time (T) was 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. (Embodiment 3) Same effective diameter 10 m as in Embodiments 1 and 2
A similar cycle life test was performed using a battery using a positive electrode grid of m under charging conditions with different current and time. 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) Further, effective diameters are 8 mm, 12 mm, 1
A battery was manufactured using a 4 mm (D = 8, 12, 14) positive electrode plate, 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 Example 4.
The results are shown in FIG. As is clear from the test results, assuming that the effective diameter of the positive electrode grid of the battery is D mm and the charging time is T time, T ≦ 3 when D = 14, T ≦ 4 when D = 12, and T ≦ 4 when D = 10. ≦ 5, T ≦ 6 when D = 8
When the battery is charged under the condition of, that is, when a battery using a positive electrode grid with an effective diameter Dmm is charged (10-0.5D)
It can be seen that if the battery is charged within the time, the life performance is significantly improved.

Further, in a lattice where the effective diameter of the lattice is not uniform, the same effect can be obtained if the arithmetic method, that is, the average effective diameter is used as a representative value of the effective diameter and charging is performed by the charging method according to the present invention. I was able to.

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 effective grid diameters.

FIG. 7 is a diagram for explaining the effective diameter of the lattice.

Claims (1)

[Claims] 1. A method of charging a lead-acid battery using a lead alloy grid containing substantially no antimony and having an effective diameter of the positive electrode grid of 16 mm or less, wherein the effective diameter of the positive grid of the battery to be charged is D (mm), T ≦ 10−, where T (hour) is the time from the start of charging to the end of charging (charging time)
A method of charging a lead storage battery, characterized in that charging is completed within a charging time represented by 0.5D.