JP2002208444A - Maintenance method of lead battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the life property of a lead battery which is made to charge and discharge during use, and left open circuited after discharged. SOLUTION: For the maintenance method of a lead battery which is left as it is after discharged, and made to charge or discharge afterwards, the battery is made to continue a weak discharge with a current weaker than the ordinary discharging current during the period of being left. It is recommended to carry out the weak current discharge within 5 minutes after discharging to the load, and it is recommended to carry out the weak current discharging with a current of 1/100-1/20,000 of a rated capacity of the battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for maintaining a lead battery which is charged and discharged during use.

[0002]

2. Description of the Related Art Conventionally, a maintenance method of a lead battery which involves charging and discharging during use is based on an open circuit state until the next charging or discharging after the discharging of a main target load is performed. Often left unattended.

[0003]

When the battery is left in an open circuit state after the end of the discharge as described above, as shown in FIG. During the standing period, self-dissolution / precipitation is repeated, and the crystals are coarsened, and the activity is reduced accordingly.

[0004] As a result, the reaction efficiency of the battery at the time of charging is reduced, and the active material is sulphated due to insufficient charging, or when overcharging is performed to compensate for the reduced charging efficiency, corrosion of the positive electrode grid is caused. Deterioration of electrodes such as acceleration has progressed, which has been a cause of deteriorating the life performance of lead batteries.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is applicable to a main target load during a period from the end of discharging to a main target load to the next charging or discharging. By continuously performing a discharge weaker than any of the above discharges (hereinafter, referred to as a weak discharge), self-dissolution and precipitation of lead sulfate crystals generated on the electrode by the discharge are suppressed, and the activity is maintained.

[0006] By this weak discharge, the precipitation form of the lead sulfate crystal immediately after the discharge can be maintained as shown in FIG. 2, so that subsequent charging can be accepted with high efficiency. A reduction in life performance can be suppressed.

It is preferable that the weak discharge after the end of the discharge to the main target load be started within 5 minutes immediately after the end of the discharge to the main target load.

Further, the magnitude of the weak discharge after the end of the discharge to the main target load is determined to be not more than (1/100) × C and not more than (1/20000) × C with respect to the battery capacity C. Is preferable in order to prevent overdischarge of the battery and obtain the above-mentioned effect.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention uses a lead-acid battery as an on-board power supply, and applies a weak discharge after the end of discharge to a main load to all small loads such as a computer, an electric memory, and an electric resistance. All the systems that can be performed, such as cars, uninterruptible power supplies, electric vehicles,
The present invention can be applied to a lead battery maintenance method performed in a hybrid vehicle, a load leveling system, and the like.

[0010]

Embodiments of the present invention will be described below.

FIGS. 3 and 4 show that a battery with a capacity of 85 Wh at a 3-hour rate is discharged at a discharge depth of 80% (3 hour rate) (hereinafter referred to as main discharge). 2 shows a change in capacity during a cycle life test in which the battery is charged.

In FIG. 3, 1 is an instantaneous charge without leaving the battery after the main discharge, and 2 is a battery that is left for 5 minutes after the main discharge and subsequently for 4 hours and 55 minutes (1/1000). × C
3 was left for 1 hour after the main discharge, followed by 4 hours (1/1000) × C
4 is the one charged after the weak discharge was performed, and 4 was charged after the open circuit was left for 5 hours after the main discharge.

As shown in FIG. 2 by setting the leaving period from the end of the main discharge to the start of the 1/1000 C discharge within 5 minutes, 10% of the ideal charge / discharge condition with no leaving is set. It is possible to keep the life performance within the range.

In FIG. 4, 5 is (1/100) ×
C and 6 are (1/1000) × C, 7 is (1/20000)
× C and 8 are currents of (1/30000) × C, respectively, in which weak discharge was performed for 5 hours from the end of main discharge to charging.

As shown in this figure, if the weak discharge from immediately after the end of the main discharge to the charge is performed with a current having a magnitude of (1/100) × C or less (1/20000) × C or more,
There is almost no difference in the life transition.

Theoretically, it is conceivable that the same effect can be obtained by discharging a current of (1/100) × C or more, but in this case, the battery is likely to be in an overdischarged state, which is not practical. .

On the other hand, when the battery is discharged at a current of (1/20000) × C or less, the effect of suppressing the self-dissolution and precipitation of the generated lead sulfate crystals is reduced, and as shown in FIG. The life performance decreases.

This embodiment shows a simulated experimental result on the life transition of a single battery. The same effect can be obtained by performing the same control in a system in which a battery is actually incorporated.

In this embodiment, the case where charging is performed after main discharge has been described. However, even when main discharge is intermittently repeated and an open circuit is conventionally left during the main discharge,
The effect of suppressing the deterioration of the life performance by applying the weak discharge of the present invention during the period of leaving the open circuit can be similarly obtained.

Further, even in an environment where the battery is not returned to a fully charged state and maintained in a state where lead sulfate crystals remain in the electrode during charging after the main discharge, By adapting the weak discharge of the present invention to its holding period, the effect of suppressing a decrease in the life performance can be obtained similarly.

[0021]

As described above, according to the first aspect of the present invention, in a lead battery used in any environment, a weak discharge occurs during a period from the main discharge to the next charge or discharge. Is performed on the battery, it is possible to bring out a life performance close to the capability originally possessed by the battery.

According to the second aspect, the effect of the first aspect can be remarkably obtained.

Further, according to the third aspect, the effect of the first aspect can be achieved by preventing overdischarge.

[Brief description of the drawings]

FIG. 1 is a photomicrograph showing the behavior of a lead sulfate crystal generated by a main discharge when left in an open circuit.

FIG. 2 is a micrograph showing the behavior of a lead sulfate crystal when a weak discharge is applied immediately after a main discharge.

FIG. 3 is a graph showing the effect of the period from the end of main discharge to the start of weak discharge on life performance.

FIG. 4 is a graph showing the effect of the magnitude of a weak discharge current on life performance.

Claims (3)

[Claims] 1. A method for maintaining a lead battery in which a load is discharged and then left to stand and then charged or discharged is characterized in that a weak discharge is performed with a current smaller than the discharge current during the standing period. How to maintain lead batteries. 2. The method according to claim 1, wherein the weak discharge is started within 5 minutes after the discharge to the load. 3. The lead battery maintenance method according to claim 1, wherein the weak discharge current is 1/100 to 1/20000 with respect to the rated capacity of the lead battery.