JP2000243457A - Method for charging lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proper charge to a lead-acid battery by allowing a charge current to have a specific relationship in a multistage constant-current charge finished in the nth process. SOLUTION: Shown in an expression is a charge current: in the expression, I1 is the charge current of a first process, n is an integral of 3 or more. Preferably, the charge in the last stage is an amount of charge electricity until the previous stage or three or more of multi-stage constant-current charge finished by the time calculated by charge time; where the number of charge stages is n, the charge current has a relationship shown in the expression. By setting the charge current low, the rise of the electric current density is low so that the reduction in the amount of charge electricity from the discharge condition to hydrogen generation due to repeated cycles can be suppressed. Accordingly, when the electric current is set low, accuracy of the amount of discharge electricity until the hydrogen generation assumed from the amount of the charge electricity becomes high. Since low charge current prolongs charge time, setting the charge current so low is not preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for charging a lead storage battery.

[0002]

2. Description of the Related Art As a method for charging a lead storage battery, there are various charging methods such as constant voltage charging, semi-constant voltage charging, constant current charging, and two-stage constant current charging. Then, in order to fully exhibit the cycle life capability of the lead storage battery, proper charging without insufficient charging or overcharging is required. Among them, the two-stage constant current charging is widely adopted because of its easy handling. Conventional two-stage constant current charging is a method in which the charging voltage of a battery is detected in the first-stage charging, the current is changed to a low current in the second-stage charging, and the charging is terminated by a timer.

[0003]

In the two-stage constant current charging, the time until the voltage of the rechargeable battery reaches the detection voltage determines the amount of electricity charged in the first stage. The amount of charge in the first stage has a substantially constant ratio with respect to the amount of discharge, so that if the amount of discharge is constant, it is possible to charge an appropriate amount of charge. But,
In normal cycle applications, the amount of discharge electricity is not constant. In the second-stage charging, a constant amount of electricity is supplied to the lead storage battery by a timer in which a charging time is set in advance, regardless of the amount of discharged electricity before charging. As a result, if the discharge before charging is shallow, overcharging may occur, while if discharging is deep, insufficient charging may occur.
It was difficult to set the timer time for proper charging. The present invention solves one of the drawbacks of the conventional two-stage constant current charging system, namely, the problem of supplying a constant amount of charged electricity to a lead storage battery regardless of the amount of discharged electricity before charging. It is an object of the present invention to provide a charging method for performing proper charging of a storage battery with little excess or deficiency.

[0004]

According to the present invention, there is provided a charging system having at least two or more steps for detecting a charging voltage of a lead storage battery and proceeding to a next charging step, followed by a constant current charging. In the multi-stage constant current charging in which charging is completed in the n-th step, when the charging current in the first step is I ₁ and the charging current in the n-th step is In, the charging current is I _{1 > I 2>...> I n} -1 ≦ I n ( where n is a integer of 3 or more) was charging method to.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a lead storage battery, the normal detection voltage of 2.40 to 2.45 V / cell is a voltage at which hydrogen starts to be generated at room temperature. The particles are aggregated, and the surface area of the aggregated lead particles is reduced. When the surface area of the lead particles decreases, the current density increases, the efficiency of the charge / discharge reaction decreases, hydrogen is easily generated, and the charging voltage is easily increased. Therefore, by repeating charge and discharge,
The amount of electricity charged from the discharged state to the generation of hydrogen is reduced.

[0006] Therefore, by setting the charging current low, it is possible to suppress the decrease in the amount of charge from the discharge state due to the repetition of the cycle to the generation of hydrogen by reducing the rise in the current density. Therefore, the accuracy of estimating the amount of discharged electricity from the amount of charged electricity increases until the generation of hydrogen when the current is set low. However, if the charging current is reduced, the charging time becomes longer, so it is not preferable to reduce the charging current too much. Therefore, by detecting the charging voltage with the lowest current for charging, the amount of discharged electricity can be estimated from the amount of charged electricity with the highest accuracy among the set charging conditions.

[0007]

EXAMPLE A charge amount measurement and a charge / discharge cycle test were performed on a sealed lead-acid battery having a voltage of 12 V and a rated capacity of 60 Ah.

The charging specifications are five-stage constant current charging with n = 5, the first stage is 0.2 CA, the second stage is 0.1 CA, the third stage is 0.05 CA, the fourth stage is 0.025 CA, As a method of detecting the voltage at the fifth stage at 0.025 CA and terminating the charging at the first to fourth stages, the detected voltage is 2.4 V / cell, that is, 14.4 V, and the charging at the fifth stage is performed by a timer. The system was terminated. Discharge is 12Ah and 44A by pattern discharge
h. The ambient temperature was 25 ± 2 ° C.
FIG. 1 shows the charging characteristics of this storage battery. FIG.
The transition of the amount of charged electricity in the first stage and the first to fourth stages in 200 cycles after the initial stage with the amount of discharged electricity is shown.

As is clear from the results of FIG.
It can be seen that the charge amount of A, 0.1 CA clearly decreases as the cycle progresses. On the other hand, 0.025C
It can be seen that the charge amount of A, 0.05 CA is stable with little change over the course of the cycle.

Next, FIG. 3 shows that after the discharge of 12 Ah and 44 Ah
The amounts of charge in the first to fourth stages during charging after discharging are shown.

As is apparent from the results shown in FIG. 3, the difference between the insufficient charge (difference between the amount of discharged electricity and the amount of charged electricity) after the discharge of 12 Ah and the discharge of 44 Ah is smaller as the current is lower.

That is, by detecting the voltage with a low charging current, the charging can be performed with little change in the amount of charged electricity due to the lapse of the cycle and in the amount of charged electricity due to the difference in the amount of discharged electricity.

However, as described above, when the charging current is reduced, the charging time becomes longer. Therefore, the charging is performed with the lowest current during the charging up to the detection voltage, and further, the charging is performed for a certain time with the same or higher current. By doing so, charging without excess and deficiency becomes possible.

[0014]

As described above, by using the charge pattern of the present invention for a lead storage battery for cycle use, it is possible to charge the lead storage battery without excess or deficiency, which is extremely useful in practice.

[Brief description of the drawings]

FIG. 1 is a diagram showing charging characteristics according to the present invention.

FIG. 2 is a diagram showing a change in the amount of charge after 44 Ah discharge with each charge current cycle.

FIG. 3 is a diagram showing the difference between the amount of discharged electricity and the amount of charged electricity at each charge current after 12Ah discharge and after 44Ah discharge.

Claims (2)

[Claims] After detecting the charge voltage of a lead storage battery, the process proceeds to the next stage charging, and the last stage charging is completed in an arbitrarily set time. when the stage, the charging current I is I _1> I _2> ...> a method of charging a lead-acid battery, characterized in that the I _n-1 ≦ I _n (where n is a integer of 3 or more). 2. After detecting the charging voltage of the lead storage battery, the process proceeds to the next stage charging, and the final stage charging is completed in three or more stages, which is completed in the time calculated from the amount of charge electricity or the charging time up to the previous stage. in the constant current charging method, when the charging stages is n stages, characterized in that the charging current I and _{I 1> I 2>...>} I n-1 ≦ I n ( where n is a integer of 3 or more) Method for charging lead storage batteries.