JP2000357538A - Maintenance method of control valve type lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent capacity drop in a battery, electrolyte leakage, and breakdown of a battery jar by filling inert gas in a battery after start of float charge and/or after recovery charge. SOLUTION: Filling of inert gas only after initial charge, or after initial charge and after start of float charge is insufficient, and by filling inert gas after recovery charge, pressure reduction within a battery can be prevented. In a word, since part of the inert gas is evacuated, by recovery charge inert gas is filled after recovery charge. As the inert gas, N2, He, Ar, and a mixture of them can be used. In a battery in which the time from initial charge to start of float charge is short, filling of inert gas after initial charge can be omitted. In the battery in which the time from after start of float charge to discharge is short, filling of inert gas after start of charge can be omitted. In the battery in which distance between discharge and the next discharge is short, filling of inert gas every recovery charge can be omitted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a maintenance method for a control valve type lead battery which prevents a battery case from being dented when a control valve type lead battery is used in a float charging system.

[0002]

2. Description of the Related Art A conventional control valve type lead-acid battery is provided with an exhaust valve in a battery case or a lid. When gas is generated from an electrode plate during charging, the gas pressure inside the cell chamber exceeds a specified value. When the gas pressure inside the cell chamber is reduced due to the oxygen gas absorption of the negative electrode, etc.
The structure prevents gas from entering the interior. Due to the fluctuations in the gas pressure inside these cell chambers, the battery case bulges outward (hereinafter, the gas pressure in this case is referred to as positive pressure) or is depressed inward (hereinafter, the gas pressure in this case is referred to as negative pressure). .

When a positive pressure is applied to the battery case and the battery case wall swells outward, a gap is formed between the positive electrode plate or the negative electrode plate and the separator, the contact area of each of them decreases, and the charge / discharge performance decreases.
As a measure to prevent this, the wall thickness of the battery case can be designed to be thick,
Alternatively, the strength of the battery case wall was increased by installing a reinforcing material or the like. Also, a safety valve is attached to the lid of the battery, and when the internal pressure in the cell chamber exceeds a specified value, the valve is opened to release gas to the outside so that the battery case does not expand.

On the other hand, when negative pressure is applied to the battery case and air enters the cell chamber, oxygen in the air is absorbed by the negative electrode plate, causing a reduction in capacity. It has a structure that does not allow it. Therefore, the battery case may be dented when the pressure becomes negative, and the battery case may be damaged in severe cases. However, there is no effective countermeasure against this.

When the battery is used in a cycle,
Since gas was generated from the electrode plate during charging, a positive pressure was generated in the cell chamber, so that there was not much problem.

[0006] However, in the case of a battery for a backup power supply (UPS) at the time of an emergency power failure, a so-called float charging method in which charging is continued at a constant voltage is generally used. In this charging method, since the current value is small, the amount of generated gas is small, and the internal pressure in the battery cell chamber may become negative.

[0007]

As described above, when a battery case dent occurs due to a negative pressure, the battery case may be destroyed as described above. The electrolyte is squeezed out and accumulates at the bottom of the battery case, causing a reduction in capacity. Further, if the dent continues for a long period of time, there is a problem that the battery case causes creep destruction and leaks.

There are three possible patterns for generating the negative pressure. One is that while the battery is left immediately after its production (first charge) until it is charged at the place of use, oxygen in the battery case is absorbed by the negative electrode, and hydrogen permeates outside the battery case, creating a negative pressure. Is the case. The second is that when the voltage in the early stage of float charging is polarized to the negative electrode side and the amount of hydrogen generated from the negative electrode is large, the pressure is positive, but liquid reduction due to water decomposition and deterioration of the electrode plate, especially deterioration of the negative electrode In this case, the polarization shifts to the positive electrode side with the progress of the sulfation, which is the cause, and the amount of generated hydrogen decreases and a negative pressure is generated. Third, during float charging from the recovery charge after discharge (use) to the next discharge, oxygen in the battery case is absorbed by the negative electrode, and hydrogen permeates outside the battery case, creating a negative pressure. This is the case.

Conventional technology, for example, Japanese Patent Application Laid-Open No. 63-1285
No. 68 proposes a method in which an inert gas is supplied after the battery is completed to replace the inside of the battery with the inert gas.

However, this method can solve the first pattern, but has little effect on the second and third patterns. This is because even if an inert gas is filled immediately after production, a large amount of hydrogen is generated at the beginning of float charging or at the time of recovery charging, the inside of the battery case becomes positive pressure, and the inert gas is discharged together with hydrogen from the safety valve. is there. The present invention has been made in view of the above problems, and an object of the present invention is to prevent a battery case of a control valve type lead battery used in a float charging system from being dented during standing or during float charging. Accordingly, it is an object of the present invention to prevent a decrease in the capacity of a lead battery, leakage of liquid, and damage to a battery case.

[0011]

In order to achieve the above object, the maintenance method of the present invention is provided after the start of float charging or /
And charging the battery with an inert gas after the recovery charge.

[0012] It is preferable that the control valve type lead battery is charged with an inert gas after the battery is assembled and charged for the first time.

The inert gas is preferably a single or composite gas of nitrogen, helium and argon. These gases have a lower permeability to the outside of the battery case than hydrogen and do not react with the electrode plates, so they remain in the space inside the battery cell room and eliminate the negative pressure in the battery cell room. can do.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

A battery is formed by using a non-chemically formed positive electrode and negative electrode prepared by a known method and a sulfuric acid aqueous solution having a specific gravity of 1.26 (25 ° C.) as an electrolytic solution, with a constant current up to 250% of the theoretical capacity of the positive electrode. It was charged for 50 hours. The rated capacity (C) of this battery was 300 Ah / 5 HR.

After the initial charge, the battery was replaced with a rubber valve as it was to obtain a completed battery. Immediately after the first charge, when replacing the rubber stopper, nitrogen gas is filled through a syringe needle built into the cap with a gas injector equipped with a cap that fits into the exhaust pipe and prevents air from flowing inside and outside of the cell Then, after the inside of the battery cell chamber reached atmospheric pressure (101 kPa) or more, a rubber stopper was quickly attached, and the completed battery was designated as battery B. After leaving battery B for another 16 hours, 2.2
Float charging was performed at 75 V / cell (25 ° C.), and after one day, nitrogen gas was injected into the battery in the same manner as Battery B. This battery was designated as battery C.

Each of the batteries A to C was float-charged for 6 years, during which time the internal pressure of the batteries was measured every year. The result is shown in FIG. From FIG. 1, it was found that the internal pressure of the battery A was reduced to about 40 kPa due to the large pressure reduction in the cell chamber due to the standing. This is presumably because oxygen in the cell chamber was absorbed by the negative electrode and hydrogen permeated outside the battery case. Battery B is
Although the pressure reduction was smaller than that of the battery A, the internal pressure decreased to substantially the same as that of the battery A. This is considered to be because oxygen and hydrogen gas in the cell chamber were replaced by nitrogen gas filling after the first charge, and the pressure reduction factor that occurred in the battery A was reduced. However, the reason why the internal pressure of the battery A was reduced to substantially the same as that of the battery A is considered that the internal pressure of the battery became positive due to the float charging, a part of the nitrogen gas was discharged to the outside from the exhaust valve, and the effect of the nitrogen gas was almost eliminated. . In the battery C, the internal pressure hardly decreased. this is,
This is because nitrogen gas was injected after the first charge and after the float charge to eliminate the respective pressure reduction factors.

Also, batteries B and C are charged every year for 3C.
(C is a numerical value indicating the value of the rated capacity) for 10 minutes, and thereafter, a test of performing a constant voltage recovery charge at a maximum current of 0.25C was performed for three years. Then, a part of the battery C was filled with nitrogen gas in the same manner as the battery B after the recovery charge after discharging. This battery was designated as Battery D. FIG. 2 shows the measurement results of the internal pressures of the batteries B, C, and D.
From FIG. 2, in the conventional battery B, the internal pressure was reduced to 70 kPa or less in one year after the recovery charge, and the battery case was dent. In battery C, the internal pressure decreased as the number of years passed, and after three years, the internal pressure decreased to approximately 80 kPa. On the other hand, in battery D, even after three years, the internal pressure hardly decreased, and no dent of the battery case was observed.

This is because when discharging during use, it is not sufficient to inject nitrogen gas only after initial charging or after initial charging and after the start of float charging. Is almost prevented. In other words, when the recovery charge is performed, part of the nitrogen gas is discharged from the exhaust valve during the charge, and the effect is considered to be reduced.
It is preferable to inject nitrogen gas after recovery charging.

In this embodiment, nitrogen is used as the inert gas. However, the same effect can be obtained by using a single gas or a composite gas of nitrogen, helium, and argon. Also, the method for filling the inert gas is not limited to the present embodiment.For example, after the cell chamber is depressurized and the existing gas is discharged, the inert gas is filled or the cell chamber is charged at a positive pressure. The same effect can be obtained even if an inert gas is filled until the state is reached.

In this embodiment, only the effects of the battery C filled with the inert gas after the initial charge and after the start of the float charge and the battery D filled with the inert gas after the recovery charge are shown. For a battery with a short period from the initial charge to the start of the float charge, the filling of the inert gas after the initial charge can be omitted, and for a battery with a short period from the start of the float charge to the discharge, the inert gas after the start of the float charge is used. If the filling of the inert gas after the recovery charge is omitted and the filling of the inert gas is performed, there is an effect compared with the conventional one. In addition, those having a short discharge interval do not have to be filled with an inert gas every recovery charge.

[0022]

As described above, according to the present invention, the dent of the battery case is prevented by filling the battery with an inert gas after the float charge of the battery is started and / or after the end of the recovery charge after the discharge. In addition, it is possible to provide a highly reliable lead storage battery which can solve the problem of battery capacity reduction, battery case creep destruction, and liquid leakage.

[Brief description of the drawings]

FIG. 1 shows the internal pressures of a battery A not filled with an inert gas, a battery B filled with an inert gas after initial charging, and a battery C filled with an inert gas after initial charging and after the start of float charging. It is a graph which shows a change.

FIG. 2 shows batteries B and C of FIG. 1 discharged and recovered and charged every year, and battery D discharged and discharged every year of battery C and then charged with an inert gas. 5 is a graph showing the internal pressure of the battery.

Claims (3)

[Claims] In a method for maintaining a control valve type lead battery used in a float charging system, the method comprises the steps of:
And a method of maintaining a control valve type lead battery, wherein the battery is filled with an inert gas after recovery charging. 2. The maintenance method for a control valve type lead battery according to claim 1, wherein the control valve type lead battery has an inert gas filled in the battery after initial charging. 3. The method according to claim 1, wherein the inert gas is a single gas or a composite gas of nitrogen, helium, and argon.