JP3496241B2 - How to charge lead storage batteries - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of charging a lead storage battery using a lead alloy grid not containing antimony, and more particularly, to a battery used by alternately charging and discharging. Charging method. 2. Description of the Related Art Although a lead-antimony alloy has been mainly used for an electrode plate grid of a lead-acid battery, a so-called maintenance-free type lead-acid battery which does not require maintenance such as water replenishment. In order to prevent water loss in the electrolyte, a lead alloy containing no antimony, such as a lead-calcium alloy, is usually used. However, in a battery using this kind of alloy, when deep charge and discharge are repeated, a passivation layer of lead sulfate is formed at the interface between the grid of the positive electrode plate and the active material during the discharge, and the capacity is quickly reduced. In particular, this tendency is remarkable in a high-performance battery using a thin electrode plate. Therefore, in an application requiring a long life, a considerably thicker electrode plate has to be used as compared with a battery using an antimony alloy, and the discharge performance has to be sacrificed. As means for preventing such an early capacity decrease, various studies have been made on alloy compositions other than the antimony alloy, which are difficult to form a passivation layer at the interface between the lattice and the active material. However, alloys comparable to antimony alloys have not yet been developed and have not been able to overcome the short-life problem. SUMMARY OF 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 alloy composition which has been conventionally studied has been studied. Not by improving the conditions under which the grid is exposed to corrosion, but by optimizing the charging method, can prevent the formation of a passive layer and significantly improve the life performance of the battery. Reached the present invention. 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 to be performed for a charging time represented by 2 ≦ T ≦ t + 2 . [0006] The reason why a 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 containing no antimony is that the grid corrosion layer has higher reactivity than the active material. This is because the corroded layer is discharged before the active material is sufficiently discharged at the time of discharge. 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 differ depending on the composition and crystal structure of the alloy. It also varies greatly depending on the electrochemical conditions such as the time under which the corrosion is performed. The present inventor has 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 electrode thickness 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.In a battery using a positive electrode plate with a certain plate thickness, the reactivity becomes higher when the cell is exposed to a higher potential for more than a certain time. It was found that a rich corrosion layer was formed. In the present invention, based on the results of this study, the charging conditions for preventing the formation of a highly reactive corrosive layer were studied in detail in relation to the thickness of the positive electrode plate, and the optimum value was found. 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. EXAMPLE 1 A positive electrode plate and a negative electrode plate each 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 arranged via a fine glass fiber separator. To form an electrode plate group, absorb and hold sulfuric acid having 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 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 ≦ t + 2 ) according to the present invention, the charging time (T)
FIG. 1 shows the results of tests conducted when the charging time (T) was set to 6, 8, and 10 hours as Comparative Examples. As is clear from the results, the charging method according to the present invention, that is, the charging time is 3 to 5
It can be seen that when the time is set as time , a good capacity change is shown, but when charging is performed for more than 5 hours, the capacity is more greatly reduced as the charging time is increased. In order to clarify the cause of the capacity decrease, when the battery charged for more than 5 hours was disassembled and inspected when the capacity reached 50% of the initial value, the interface between the grid of the positive electrode plate and the active material was determined. It was confirmed that a passivation layer was formed on the substrate. When the charging time was set to 5 hours or less, the battery was disassembled and inspected at the time of 500 cycles, but no passive layer was formed. In the case where the charging time is set to 3 hours, the capacity has changed to a low level from the beginning. This indicates that the battery is not fully charged. If done, the capacity will be restored, and there will be no particular problem in the life performance. (Example 2) The same test as in Example 1 was performed with a charging voltage of 2.5.
V and 2.3 V, respectively. 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) was set to 5 hours or less, a good capacity transition was shown. It can be seen that the longer the is, the more the capacity is reduced. (Embodiment 3) The same cycle life test was carried out using a battery using the same positive electrode plate having a thickness of 3 mm as in the case of Embodiments 1 and 2 under charging conditions of different currents and different 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. In FIG. 4, a represents a charging condition of 10A.
-2.4V for 2 hours, b is 5A-2.4V for 3 hours, c
Is 4 hours at 3A-2.4V, d is 5 hours at 2A-2.4V, e is 6 hours at 1.5A-2.4V, and f is 1A-2.
8 hours at 4V and g for 10 hours at 0.8A-2.4V. As is apparent from the results, as the charging current is increased and the charging time is shortened, the life performance is greatly improved. Particularly, when the charging time is set to 2 to 5 hours , a good capacity transition is exhibited. I understand. (Example 4) The temperature conditions of the tests shown in Examples 1 to 3 were set to 1
FIG. 5 shows the test results when the temperature was changed from 0 to 40 ° C. as a relationship between the charging time and the number of life cycles. Here, the life cycle number is 50 times the initial capacity.
It was the time when% was cut. As evident 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 set to 5 hours or less, a good capacity transition is exhibited. (Example 5) Further, the thickness is 1 mm, 2 mm, and 4 mm.
Batteries were manufactured using the positive electrode plates (t = 1, 2, 4), and cycle life tests similar to the tests shown in Examples 1 to 4 were performed under various charging conditions. FIG. 6 shows the test results together with the results of Example 4. As is clear 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 = 1
2 ≦ T ≦ 3 when t = 2, 2 ≦ T ≦ 4 when t = 2, 2 ≦ T ≦ 5 when t = 3, and 2 ≦ T ≦ 6 when t = 4. It can be seen that when charging a battery using a positive electrode plate having a thickness of tmm , if the battery is charged within 2 hours or more and within t + 2 hours, the life performance is significantly improved. In the embodiment, a constant current-
The constant voltage method was used, but the constant current-constant voltage-constant current method,
Similar effects can be obtained even when other charging methods such as a stepwise constant current method and a quasi-constant voltage method are used, if charging is performed by the charging method according to the present invention. By using the charging method according to the present invention, the life performance of a battery using a lead alloy lattice not containing antimony can be remarkably 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 is a diagram showing a life test result when a charging voltage is set to 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 a charging time and a 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)

(1) A method for charging a lead-acid battery using a lead alloy grid not containing antimony, wherein the thickness of the positive electrode plate of the battery to be charged is tmm, and charging is started and stopped. A method of charging a lead storage battery, wherein charging is terminated at a charging time represented by 2 ≦ T ≦ t + 2, where T is a time until the charging time (charging time).