JPH0850924A - Charging method for lead-acid battery - Google Patents

Abstract

PURPOSE:To control the positive electrode potential to be within a specified range during charging, and enhance life performance with a positive plate suppressed in elongation by dividing the charging area into four areas, and thereby specifying a relation between each terminal voltage and charging time in each divided area. CONSTITUTION:The charging of a lead storage battery employing a lattice made of a lead-calcium alloy as a positive plate is carried out by dividing its charging area into four areas A through D. In the area A, charging is carried out at constant current or semi-constant current, and the terminal voltage is increased as time elapses. In the area B, charging is carried out at constant current or semi-constant current, and specified voltage V1 is kept constant for the specified period of time T1. In the area C, charging is carried out at constant current or semi-constant current, and specified voltage V2 is kept constant for the specified period of time T2. A relation between each terminal voltage and the period of time for charging in the areas A through C is set to be V1<V2, and T1<T2. By this consttution, positive electrode potential is controlled to be less than a definite limit, a positive plate is made small in elongation, and life performance is thereby enhanced.

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 acid battery, and more particularly to suppressing the elongation of the positive electrode plate of a lead acid battery using a lead-calcium alloy grid as the positive electrode plate and improving the life performance of the lead acid battery. It is a thing.

[0002]

2. Description of the Related Art Lead-acid batteries, in which lead-acid batteries use a lead-calcium alloy lattice as a positive electrode plate, are increasing in number due to the need for maintenance-free batteries. The problem with this positive electrode plate is that, unlike the conventional lead-antimony-based alloy, the lattice expands greatly during use of the battery, the bond between the lattice and the active material deteriorates, and the capacity decreases early.

Constant-current-constant-voltage charging is the most common method for charging lead-acid batteries using a lead-calcium alloy for the positive electrode plate, especially sealed batteries. Lead-acid batteries have good charge acceptance after deep discharge, and a large current initially flows during constant-voltage charging. Therefore, the battery is charged with a constant current until it reaches a predetermined voltage, and is charged with a constant voltage after reaching the predetermined voltage.

In addition to the constant current-constant voltage charging, there has been proposed a charging method in which the current is increased and the terminal voltage is increased for a certain period just after shifting to constant voltage charging. . This is to charge by increasing the terminal voltage for a certain period of time even if the voltage rises to a predetermined terminal voltage.
Also, a charging method has been proposed in which the battery voltage is increased by performing constant-current charging again only for a short period at the end of constant-voltage charging.

In these constant current-constant voltage charging and the method in which the constant current is partially modified, the cycle life of the battery is short due to the elongation of the positive electrode grid, and the life is short especially in applications where shallow discharge frequently occurs. .

The present invention shows the charging characteristics of a lead-acid battery after discharging,
Measure the details separately for the positive electrode plate and the negative electrode plate and clarify the relationship between the charging voltage and the expansion of the positive electrode grid during long-term constant voltage charging to reduce the expansion of the positive electrode grid that occurs during battery use. That is, the present invention has found a charging method for extending the life.

[0007]

The present invention relates to a method for charging a lead storage battery using a lead-calcium alloy lattice as a positive electrode plate, which has a constant current or quasi-constant current in which the terminal voltage of the battery rises with time. Charging area A, and a constant voltage charging area B for maintaining a predetermined terminal voltage V ₁ for a predetermined time T ₁ ;
A constant current or quasi-constant current charging area C where the terminal voltage rises again with time and a predetermined terminal voltage V ₂ for a predetermined time T
_The constant voltage charging region D is maintained for ₂ or more, and V ₁ <
V ₂ and T ₁ <T ₂ .

[0008]

According to the charging method of the present invention, the positive electrode potential during charging is effectively suppressed below a certain limit, so that the elongation of the positive electrode plate is suppressed and the life performance of the lead storage battery is improved.

[0009]

EXAMPLE First, a sealed lead-acid battery using a lead-calcium alloy lattice was charged at a constant voltage at 45 ° C. for 6 months, and the lattice expansion of the positive electrode plate was examined. The results are shown in FIG. The unipolar potentials of the positive and negative plates are the values for the cadmium electrode, and the broken line is an estimate. Since a constant voltage was applied for a long period of time in this experiment, the potential of the positive electrode plate was 10 in FIG.
It has a stable potential after time. The lattice stretch was closely related to the charging voltage. The higher the charging voltage, that is, the higher the potential of the positive electrode plate, the greater the elongation of the lattice.

From the results of this experiment, if the charging time is constant, the lower the charging voltage, the lower the potential of the + plate,
It can be seen that the + plate stretches less and has a longer life.

Next, FIG. 2 shows the characteristics of the lead storage battery during constant current-constant voltage charging. Here, the battery is a sealed lead-acid battery of 100 Ah (5 hR), the constant current charging current is 20 A (5 hR current), and the constant voltage charging potential is 2.5 V / cell. In the time region X, the terminal voltage rises with the lapse of time and is charged with a constant current. In the time region Y, the terminal voltage is constant, and the charging current sharply decreases with time. At this time, the potential of the positive electrode plate rises in the region X, decreases in the region Y, and then shows a constant value. The potential of the negative electrode plate decreases in the region X, but to a lesser extent than that of the positive electrode plate. In the region Y, the potential of the negative electrode plate decreases and then shows a constant value, which is the same as the change in the potential of the positive electrode plate. This is because the region Y has a constant voltage and the potential difference between the positive electrode plate and the negative electrode plate is constant. Thus, in constant current-constant voltage charging, which is a conventional standard charging method, the potential of the positive electrode plate is before and after moving from the constant current region to the constant voltage region, that is, at the portion indicated by the arrow in FIG. It has been found that the temporary increase in temperature is a characteristic of the lead storage battery.

It is obvious that the elongation of the positive electrode plate is determined not by the terminal voltage but by the potential of the positive electrode plate.
Therefore, in order to reduce the elongation of the positive electrode plate, it is important to keep the potential of the positive electrode plate as low as possible during charging, that is, not increase the potential of the positive electrode plate.

In the conventional constant current-constant voltage charging, it is noted that the potential of the positive electrode plate becomes high only for a short time before and after the constant current is changed to the constant voltage, and only at that time, the voltage applied to the battery is increased. To lower the potential of the positive electrode plate,
If the battery is charged with a voltage of a predetermined value during a long charging time thereafter, it becomes possible to charge the battery while avoiding a voltage at which the positive electrode plate stretches significantly.

Next, for a sealed lead-acid battery with a discharge capacity of 5 hours of 100 ampere hour (Ah), constant current charging with a maximum current of 20 A and constant voltage charging with V ₁ = 2.35 V were performed for about 2 h and V _2. FIG. 3 shows the charging characteristics according to the method of the present invention when a constant voltage of 2.5 V was charged for 14 hours. Compared with the conventional method, the potential of the + plate is about 0.1V
It can be kept low. The amount of charge is 10 of the previous discharge
When the ratio is 5 to 110%, the charging is almost completed, but the conventional method can perform the charging in about 10 hours, and the method of the present invention can perform the charging in almost the same time, and the charging time is hardly extended. In addition, 2.35V
It takes about 15 hours for constant voltage charging.

Further, FIG. 4 shows the result of the life test by the shallow charge / discharge cycle in which the discharge was carried out at 20 A for 1 hour and the charge was carried out by the above two kinds of methods. However, the charging time was set to 11 hours for the convenience of the test. That is, V ₁ = 2.
_{35V, V 2 = 2.5V, T} 1 = 2h, T 2 = 5~6h
Is. As a result of disassembling after 200 cycles and examining the elongation of the positive electrode plate, the battery charged by the method according to the present invention was 3.4% in the width direction and 2.1% in the height direction. Then, 4.7% in the width direction and 2.9 in the height direction.
%, Which was about 50% of the elongation of the lattice of the battery charged by the method according to the present invention.

[0016]

According to the charging method of the present invention, since the elongation of the positive electrode plate is suppressed, the life performance of the battery is improved, and its industrial value is enormous.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the potential of a positive electrode plate and elongation.

[Fig. 2] Constant current-constant voltage charging characteristic diagram

FIG. 3 is a charging characteristic diagram according to the charging method of the present invention.

FIG. 4 is a diagram comparing life test results.

Claims (1)

[Claims] 1. A constant current or quasi-constant current charging region A in which the terminal voltage of the battery rises with time, and a constant voltage charging region B in which a predetermined terminal voltage V ₁ is maintained for a predetermined time T ₁ .
A constant current or quasi-constant current charging area C where the terminal voltage rises again with time and a predetermined terminal voltage V ₂ for a predetermined time T
_The constant voltage charging region D is maintained for ₂ or more, and V ₁ <
A method of charging a lead storage battery using a lead-calcium alloy lattice as a positive electrode plate, wherein V ₂ and T ₁ <T ₂ .