JP3582068B2 - How to charge lead storage batteries - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a method for charging a lead storage battery using a lead alloy grid not containing antimony, and more particularly, to a method for charging a battery used by alternately charging and discharging.
[0002]
[Prior art and its problems]
Conventionally, lead-antimony alloys have been mainly used for the plate grid of lead-acid batteries.However, maintenance-free lead-acid batteries, which do not require maintenance such as water replenishment, are used to prevent loss of electrolyte water. Usually, a lead alloy containing no antimony, such as a lead-calcium alloy, is used.
[0003]
However, in batteries using this kind of alloy, when deep charge and discharge are repeated, a passive phase layer of lead sulfate is formed at the interface between the grid of the positive electrode plate and the active material during discharge, and the capacity decreases early. This tendency is particularly remarkable in a high-performance battery using an electrolyte having a high specific gravity. Therefore, in applications that require a long life, an electrolyte having a low specific gravity has to be used, and the discharge performance has to be sacrificed.
[0004]
As means for preventing such early capacity reduction, various studies have conventionally been made on alloy compositions other than antimony alloys and in which a passive layer is difficult to be formed at the interface between the lattice and the active material. Alloys comparable to have not yet been developed and have not been able to overcome the short-life problem.
[0005]
Means for Solving the Invention
The present inventors have conducted intensive studies on a method for preventing the formation of a passive layer at the interface of a positive electrode lattice containing no antimony.As a result, the lattice was not corroded, not by the improvement of the lattice alloy composition, which has been conventionally studied. It has been found that by optimizing the conditions under which the charge is applied, that is, by optimizing the charging method, the formation of a passive layer can be prevented and the life performance of the battery can be remarkably improved. The gist is to select a charging time suitable for the specific gravity of the electrolyte of the battery. Specifically, the battery is to be charged within a charging time represented by 2 ≦ T ≦ 71-50 s, where s is the electrolyte specific gravity of the battery to be charged and T is the charging time.
[0006]
The reason why the passive layer of lead sulfate is formed at the interface between the active material and the grid of the positive electrode plate using a lead alloy grid that does not contain antimony is that the grid corrosion layer is more reactive than the active material and is active during discharge. This is because the corroded layer is discharged before the substance is sufficiently discharged. On the other hand, the corrosion layer of the antimony alloy lattice is less likely to be discharged than the active material and is stable. It is considered that such a difference in reactivity of the corroded layer is caused by a difference in composition or structure of the corroded layer.
[0007]
The composition and structure of the corroded layer differs depending on the composition and crystal structure of the alloy. In addition, other conditions such as the potential at the lattice interface, current density, and hydrogen ion concentration (pH) that cause the lattice to be corroded and its corrosion It changes greatly depending on the electrochemical conditions such as the time under which the conditions are maintained.
[0008]
The present inventors have focused on the conditions under which such a corroded layer is formed, and as a result of repeated studies, the reactivity of the corroded layer shows that the specific gravity of the electrolyte solution, which is closely related to the pH of the lattice interface, The time during which the interface is exposed to a high potential, that is, the charging time, has a significant effect.In a battery using an electrolyte with a certain specific gravity, a corrosive layer that is highly reactive when exposed to a high potential for more than a certain time Is formed.
[0009]
The present invention has been made based on the results of this study, and has studied in detail the charging conditions for preventing the formation of a highly reactive corrosive layer in relation to the specific gravity of the electrolytic solution, and has found the optimum value. By using the charging method according to the present invention and terminating charging before a highly reactive corrosive layer is formed, it is possible to prevent the formation of a passive layer and significantly improve the battery life performance. Become. The details will be described below using examples.
[0010]
【Example】
(Example 1)
A positive electrode plate and a negative electrode plate each of which is filled with an active material in a lead-0.1% calcium alloy lattice are alternately laminated via a fine glass fiber separator to form an electrode plate group, and have a specific gravity of 1.32 (s = 1.32). ) Was absorbed and held to produce a 2V-6Ah sealed lead-acid battery. The specific gravity of the electrolyte was calculated from the open circuit voltage and confirmed.
[0011]
Using this battery, a charge / discharge cycle life test was performed at room temperature (25 ° C.) under various charging conditions. Discharging was performed up to 1.65 V at 2 A, and charging was performed under a constant current-constant voltage system (3 A-2.4 V). As an example of the charging method ( 2 ≦ T ≦ 5 ) according to the present invention, the charging time (T) was set to 3, 4, and 5 hours. As a comparative example, the charging time (T) was set to 6, 8, and 10 hours. FIG. 1 shows the results of a test performed for the case where the test was performed. As is apparent from the results, the charging method according to the present invention, that is, when the charging time is set to 2 hours or more and 5 hours or less, a good capacity change is exhibited, but when the charging is performed for more than 5 hours, the charging is performed. It can be seen that the longer the time, the more the capacity is reduced.
[0012]
In order to clarify the cause of the capacity reduction, when the battery charged for more than 5 hours had its capacity reduced to 50% of the initial value, the battery was dismantled and inspected. It was confirmed that a layer was formed. When the charging time was set to 2 hours or more and 5 hours or less, the battery was disassembled and inspected at 500 cycles, but no passive layer was formed.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
In the case where the charging time was set to 3 hours, the capacity changed from the initial stage to a lower level, which indicates that the battery was not fully charged. Recovers and there is no particular problem in the life performance.
(Example 2) The same test as in Example 1 was also performed when the charging voltage was set to 2.5 V and 2.3 V. FIG. 2 shows the result when the charging voltage was set to 2.5 V, and FIG. 3 shows the result when the charging voltage was set to 2.3 V. As is clear from these results, at any charging voltage, when the charging time (T) is set to 2 hours or more and 5 hours or less, a favorable capacity change is shown. However, when charging is performed for more than 5 hours. It can be seen that the longer the charging time, the more severe the capacity drop.
(Example 3) The same cycle life test was carried out using batteries having the same specific gravity of the electrolytic solution of 1.32 as in the case of Examples 1 and 2 under different charging conditions with different currents and times. Note that the charging method was a constant current-constant voltage method, and charging conditions were set so that each battery was almost fully charged. FIG. 4 shows the results of the test.
[0014]
In FIG. 4, a is a charging condition of 2 hours at 10A-2.4V, b is 3 hours at 5A-2.4V, c is 4 hours at 3A-2.4V, and d is 5 hours at 2A-2.4V. Time, e is 6 hours at 1.5A-2.4V, f is 8 hours at 1A-2.4V, and g is 10 hours at 0.8A-2.4V.
[0015]
As is evident from these results, the longer the charging current and the shorter the charging time, the more the life performance is improved. In particular, when the charging time is set to 2 hours or more and 5 hours or less, a good capacity change is exhibited. I understand.
(Example 4) FIG. 5 shows the test results when the temperature conditions of the tests shown in Examples 1 to 3 were changed from 10 to 40 ° C. as a relationship between the charging time and the number of life cycles. Here, the number of life cycles was set at a point when 50% of the initial capacity was cut. As is apparent from the results, the cycle life performance is improved as the charging time is shortened. In particular, when the charging time is set to 2 hours or more and 5 hours or less, a good capacity transition is exhibited.
(Example 5) Further, batteries were manufactured using electrolytes having specific gravities of 1.28, 1.30, 1.34 (s = 1.28, 1.30, 1.34), and various charging conditions were used. A cycle life test similar to the test shown in Examples 1 to 4 was performed. FIG. 6 shows the test results together with the results of Example 4. As is clear from the test results, assuming that the specific gravity of the electrolyte of the battery is s and the charging time is T, 2 ≦ T ≦ 4 when s = 1.34, 2 ≦ T ≦ 5 when s = 1.32, When charging is performed under the condition of 2 ≦ T ≦ 6 when s = 1.30 and 2 ≦ T ≦ 7 when s = 1.28, that is, when charging a battery using an electrolyte having a specific gravity s , 2 It can be seen that if the battery is charged for more than an hour and within (71-50 s) hours, the life performance is remarkably improved.
[0016]
In the embodiment, the constant current-constant voltage method is used as the charging method. The same effect can be obtained if the charging is performed by the charging method according to the present invention.
[0017]
【The invention's effect】
By using the charging method according to the present invention, the life performance of a battery using a lead alloy lattice substantially containing no antimony can be significantly improved. Further, according to the present invention, it is possible to use a high-performance battery which has not been practically used because of its short life, and its industrial value is very large.
[Brief description of the 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 a charging voltage is set to 2.5 V in Example 2. FIG. FIG. 4 shows the results of a life test at 0.3 V. FIG. 4 shows the results of the life test of Example 3. FIG. 5 shows the relationship between the charging time and the number of life cycles. Diagram showing the relationship between charging time and number of life cycles in different batteries

Claims (1)

A method for charging a lead-acid battery having a specific gravity of 1.24 or more and 1.38 or less in a fully charged state using a lead alloy grid substantially free of antimony, wherein the charged battery has a specific gravity in a fully charged state. A lead-acid battery wherein charging is completed within a charging time represented by 2 ≦ T ≦ 71-50 s, where s is an electrolyte specific gravity, and T (time) is a time (charging time) from the start of charging to the end of charging. Charging method.

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