JPH05316663A - Charging method for storage battery - Google Patents

Abstract

PURPOSE:To prevent a storage battery from being overcharged even when the storage battery does not discharge electricity much. CONSTITUTION:Strong charging control is switched to weak charging control when the terminal voltage V of storage battery reaches a gas generating voltage Ve. The weak charging time Tk is counted until the variation V of the terminal voltage V per unit time becomes lower than a prescribed fully-charged state discriminating value Vs from the start of weak charging and the charging time is changed in accordance with the duration of the weak charging time Tk. Since the weak charging time is changed by utilizing such a characteristic that the weak charging time Tk varies depending on the discharging state of the battery, no overcharging nor insufficient charging occurs and the service life of the battery is not shortened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to charging a storage battery,
This is a technology that estimates the degree of discharge from the state of charge progress and changes the charge time to perform sufficient charge.

[0002]

2. Description of the Related Art Conventionally, as a method of charging a storage battery, there is a two-stage constant current charging method in which a voltage detection relay and a timer are combined. The change in terminal voltage due to this charging method is schematically shown in FIG. At the beginning of charging, the terminal voltage is gradually increased by performing strong charging with a relatively large current,
When the charging is near the end of the period, electric energy is consumed for electrolysis of water in the electrolytic solution to generate oxygen and hydrogen gas. The maximum gas generation occurs when the terminal voltage of the storage battery becomes equal to or higher than the gas generation voltage, and the current is reduced from here to perform weak charging for a predetermined timer time. Then, the terminal voltage once drops, then gradually rises again and finally stops rising, and the battery is charged as it is until a predetermined time.

[0003]

Since charging is a chemical change, charging characteristics differ depending on whether the temperature of the electrolytic solution is high or low, and the terminal voltage of the storage battery is high when the temperature of the electrolytic solution is low and low when the temperature of the electrolytic solution is high. In addition, when a storage battery having a different discharge degree is charged for a certain timer time, it becomes overcharged or insufficiently charged, and the life of the storage battery is shortened. Therefore, the applicant is
In the Japanese Patent Application No. 2-109325 application with two joint applicants, the terminal voltage is corrected by the electrolyte temperature of the storage battery, the weak charge timer time is calculated, and the terminal voltage is stabilized or lowered during charging. It has been proposed to detect the end of charging by detecting and to charge for a shorter predetermined additional charging time when the remaining time of the weak charging timer calculated above is long. However, in the proposal of the above-mentioned application, the predetermined additional charging time after the end of charging is sensed is for charging a fully discharged storage battery, and the degree of discharge is not taken into consideration. Therefore, if a storage battery that has not been discharged so much is charged for this predetermined additional charging time, it becomes too long and becomes overcharged. Therefore, it is an object of the present invention to prevent insufficient charging even when charging a fully discharged storage battery, and to prevent overcharging even when charging a storage battery that has not been discharged so much.

[0004]

A method of charging a storage battery according to the present invention is a method of charging a storage battery, in which strong charging is performed until a terminal voltage V of the storage battery 5 reaches a gas generation voltage Ve and then weak charging is performed for a timer time T. At the time of weak charging, the fluctuation value ΔV of the terminal voltage V of the storage battery 5 per unit time is detected, and when the fluctuation value ΔV is smaller than the full charge judgment value Vs, the timer time T is set according to the weak charging elapsed time Tk. When the fluctuation value ΔV is larger than the full-charge determination value Vs, on the contrary, the count-up is controlled to continue until the timer time T.

[0005]

The operation and effect of the invention: When the terminal voltage of the storage battery 5 reaches the gas generation voltage Ve and switches from the strong charge to the weak charge, a predetermined timer time T or calculated by the electrolyte temperature When the weak charging time Tk is counted up and it is determined that the fluctuation value ΔV of the terminal voltage V per unit time is smaller than the full charge determination value Vs, that is, the state where the full charge is substantially completed is determined, the state is changed to this state. Since the weak charge elapsed time Tk until reaching the short charge is changed depending on the discharge state of the storage battery, the timer time T is shortened and changed according to the weak charge elapsed time Tk. Even when charging, overcharging does not occur and the life of the storage battery 5 is not shortened.

In other cases, if the fluctuation value ΔV is forever larger than the full-charge judgment value Vs, it indicates that the storage battery has been over-discharged or has reached the end of its life, and the first timer time T is counted up to the end. To do. By displaying the fact that the count-up is completed up to the end, it can be determined that the replacement time of the storage battery 5 is near.

[0007]

EXAMPLE A charging device used in the charging method of the present invention is shown in FIG.
As shown in, a transformer 3 connected to an AC power source via a switch 2, a rectifier circuit 4 connected to the secondary side of the transformer 3, and a switching device connected in series to an output terminal of the rectifier circuit 4 via a storage battery 5. Element 6 and switching element 6
A chopping pulse circuit 7 for controlling ON / OFF of
A charging control circuit 8 that receives the terminal voltage measurement value u of the storage battery 5 and the electrolytic solution temperature measurement value t of the storage battery 5 and processes them as shown in the flowchart of FIG. 1 to control the chopping pulse circuit 7 is provided. The terminal voltage measurement value u is the voltage of the storage battery 5 when the switching element 6 is OFF, and is detected, for example, every 25 ms.

The charge control circuit 8 performs a strong charge control A and a weak charge control B. When the charge control circuit 8 receives the charge start command, the charge control circuit 8 enters the state of the strong charge control A, starts the strong charge control (for example, 5 ampere charge in a lead storage battery having a battery capacity of 35 Ah / 5HR), and switches the switching element 6
The chopping pulse circuit 7 is controlled so that the ON time of is longer (that is, the charging output duty ratio is larger).

The charge control circuit 8 receives the terminal voltage measurement value u and the electrolytic solution temperature measurement value t, and calculates the corrected terminal voltage V based on the following equation. V = u + C × (t−20) ... However, when t <0 ° C., t = 0, and when t> 40 ° C., t = 40. C is a constant determined by the characteristics of the storage battery 5, and for example, C = 0.06 when two 12-volt lead storages are connected in series.
The temperature of the electrolyte solution is measured by bringing the temperature detection sensor 9 into contact with the outer surface of the case of the storage battery 5, or indirectly by detecting the ambient temperature outside the case without making contact with the case.

The charge control circuit 8 calculates the corrected terminal voltage V
Is compared with the gas generation voltage Ve, and when it is determined that V <Ve, the routine of the strong charge control A is repeated at regular intervals, and when it is determined that V ≧ Ve, the process proceeds to the next weak charge control B. The gas generation voltage Ve is determined by the characteristics of the storage battery 5, and is a voltage when a large amount of gas starts to be generated at the end of charging. For example, when two 12-volt lead storage batteries are connected in series, Ve = It will be 28.8 volts. If the corrected terminal voltage V does not reach the gas generation voltage Ve 14 hours after the start of charging, it is determined that the storage battery 5 cannot be charged and the charging is stopped.

When the mode shifts to the weak charge control B, the weak charge control (for example, 2 for a lead storage battery having a battery capacity of 35 Ah / 5HR) is performed.
The chopping pulse circuit 7 is controlled so that the ON time of the switching element 6 is shortened (that is, the charging output duty ratio is reduced) by starting the ampere charging).
Also, the electrolyte temperature measurement value t is input, and the timer time T required for the weak charge control B is calculated based on the following equation. T = D + E × (20−t) ÷ 20 ... However, when t ≦ 0 ° C., t = 0, and when t> 20 ° C., t = 20. D and E are storage batteries 5
Is a constant determined by the characteristics of, for example, battery capacity 3
For a lead acid battery of 5Ah / 5HR, D = 5 and E = 3. Subsequently, the weak charging elapsed time Tk is counted up. Further, the shortened timer time Ts is calculated based on the following equation using the charging elapsed time Tk. Ts = F × Tk−G ... F and G are constants determined by the characteristics of the storage battery. For example, in a lead storage battery having a battery capacity of 35 Ah / 5HR,
F = 1.5 and G = 0.25. Weak charge elapsed time Tk
And the remaining time Tr are represented by the following equation. Tr = T-Tk ...

The weak charging elapsed time Tk is the timer time T
When they are counted up to become equal, the remaining time Tr becomes 0 and the weak charge control is stopped to complete the charging. When it is determined that they are not equal, the timer time T and the shortened timer time Ts are compared and judged, and the timer time T If it is determined that is small, the weak charge control B routine is repeated. On the contrary, when it is determined that the timer time T is longer than the shortened timer time Ts, the correction terminal voltage V obtained above is calculated.
Is compared with a preset limit voltage Vt (for example, Vt = 30 V when two 12 V lead storage batteries are connected in series). As a result, when it is determined that the correction terminal voltage V is lower than the limit voltage Vt, the routine of the weak charge control B is repeated.

On the contrary, the correction terminal voltage V is the limit voltage Vt.
When it is determined that it is larger, the variation value ΔV of the correction terminal voltage V per unit time Δh (eg, Δh = 30 minutes) is detected, and this variation value ΔV is compared with the full charge determination value Vs. to decide. This full-charge judgment value Vs is adopted based on the phenomenon that the terminal voltage rises extremely low or decreases when the storage battery 5 approaches the full-charge, and for example, two 12-volt lead storage batteries are connected in series. In some cases, Vs = 0.1 volt. When it is determined that the fluctuation value ΔV is larger than the full charge determination value Vs, it is estimated that the storage battery 5 has not reached full charge, and the weak charge control B routine is repeated. On the contrary, when it is determined that the fluctuation value ΔV is smaller than the full charge determination value Vs, it is estimated that the storage battery 5 is near full charge, and the timer time T is changed to the shortened timer time Ts obtained above. The routine of the weak charge control B is repeated.

Reduction of this timer time T Timer time T
The change to s uses the characteristic that the charging elapsed time Tk until the fluctuation value ΔV reaches the full charge determination value Vs is short because the storage battery 5 is less discharged. It is possible to prevent overcharging when charging. The correction terminal voltage V is compared and judged with the limit voltage Vt, and when the correction terminal voltage V is large, the fluctuation value ΔV is compared and judged with the fluctuation reference value Vs. , The correction terminal voltage V is the limit voltage Vt
This is to prevent the full charge judgment in such a state because the fluctuation value ΔV is in a stable state without reaching the value. In this case, even if the charge is performed until the timer time T, the charge is insufficient, and thus the charge is insufficient. The status will be displayed.

The present inventor conducted a comparison experiment of the charging method according to this embodiment and the conventional charging method with a battery capacity of 35 Ah / 5H.
R lead-acid battery was used. In Test Example 1, a 25% discharged lead-acid battery was charged by the method of this example and the conventional method, and the results of the graph shown in FIG. 3 were obtained. Test example 2
The result of the graph shown in FIG. 4 was obtained by charging a lead acid battery that had been discharged by 10%. As is clear from the above results,
When the amount of discharge is small, the charging time is shortened and overcharge is prevented.

[Brief description of drawings]

FIG. 1 is a flow chart diagram.

FIG. 2 is a circuit diagram of a charging device.

FIG. 3 is a graph showing a charge state of Test Example 1.

FIG. 4 is a graph showing a charge state of Test Example 2.

FIG. 5 is a graph showing changes in terminal voltage according to a conventional two-stage constant current charging method.

[Explanation of symbols]

 Ve Gas generation voltage T Timer time Ts Shortening timer time 5 Storage battery V Terminal voltage ΔV Fluctuation value Vs Full charge judgment value Tk Weak charge elapsed time

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[Procedure amendment]

[Submission date] May 27, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (1)

[Claims] 1. A method of charging a storage battery, comprising performing strong charging until the terminal voltage (V) of the storage battery (5) reaches a gas generation voltage (Ve) and then performing weak charging for a timer time (T).
During weak charging, the fluctuation value (ΔV) of the terminal voltage (V) of the storage battery (5) per unit time is detected, and when this fluctuation value (ΔV) is smaller than the full charge judgment value (Vs), the weak charging elapsed time The timer time (T) is shortened and changed according to (Tk) to continue counting up. On the contrary, when the fluctuation value (ΔV) is larger than the full charge determination value (Vs), the timer time (T) is increased.
The method of charging the storage battery is controlled to continue counting up until the end.