JPH11136876A - Charging of lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent insufficient charging and overcharging by obtaining required charging quantity of electricity based on discharging quantity of electricity before charging using a multi-staged current charging method which decreases a charging current value when terminal voltage during constant- current charging reaches current switching voltage. SOLUTION: The data on the electrolyte temperature or battery atmospheric temperature T of a lead-acid battery 4 is inputted from a temperature detection circuit 8. When ambient temperature T of the battery is detected, calculation of a coefficient α and a current switching voltage can be determined by detected temperature T from one temperature detection circuit 8. The coefficient αis determined from an expression: α=PT<2> +QT+R (where P, Q, and R are characteristic values of various lead-acid batteries for the range -5 deg.C to 40 deg.C). In this case, P=5.56×10<4> , Q=-3.89×10<2> , and R=1.67 are satisfied. Calculated discharging electricity quantity: Cx=α×C1 is obtained using initial charging quantity C1 of electricity, from the start of the first stage charge until switching to the second stage charging, and a required charging electricity quantity Cy=β×α×C1 is obtained. In this case, β is within the range of 1.1 of 1.3 from the characteristic values of the various lead-acid batteries for -5 deg.C to 40 deg.C.

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 storage battery used for cycling.

[0002]

2. Description of the Related Art The terminal voltage of a lead storage battery during constant current charging is detected, and when the terminal voltage reaches a predetermined current switching voltage Vo, the charging current value is reduced in a multistage constant current charging method. There is proposed a method of charging a lead storage battery that performs the following. When this charging method is used, Japanese Patent Application Laid-Open No. 7-78
As shown in JP-A-637, when the amount of discharged electricity before discharge of a lead storage battery is not constant, such as a lead storage battery used for cycle applications, the required amount of charged electricity is obtained by calculation from the amount of discharged electricity before charging, Techniques for preventing overcharging and insufficient charging have been proposed.

[0003]

However, in the technique disclosed in Japanese Patent Application Laid-Open No. 7-78637, the required amount of charged electricity is calculated from the actually measured amount of discharged electricity. There was a problem that it was not possible.

An object of the present invention is to provide a method of charging a lead storage battery which can perform proper charging without overcharging or insufficient charging even in a lead storage battery whose discharge amount is unknown.

[0005]

The present invention uses a multi-stage current charging method which detects a terminal voltage of a lead storage battery during constant current charging and reduces the charging current value when the terminal voltage reaches a current switching voltage Vo. A method of charging a lead-acid battery, which determines a required amount of charged electricity based on the amount of discharged electricity before charging, and performs charging by the required amount of charged electricity to prevent insufficient charging and overcharging, is an object of improvement.

In the present invention, the amount of discharged electricity Cx is calculated by multiplying the amount of charged electricity C1 from the start of the first stage charging to the switching to the second stage charging by a coefficient α determined by the electrolyte temperature or the battery ambient temperature T. Ask. The inventor states that the amount of charge C1 and the electrolyte temperature or the battery ambient temperature T from the start of the first-stage charge to switching to the second-stage charge have a predetermined relationship with the amount of discharged electricity Cx before charging. Was found.
Therefore, in the present invention, based on this predetermined relationship, the amount of discharged electricity Cx is calculated from the charged amount of electricity C1 and the electrolyte temperature or the battery ambient temperature T by calculation. If the amount of discharged electricity before charging can be obtained by calculation without measuring,
There is an advantage that proper charging can be performed without overcharging or insufficient charging even in a lead storage battery whose discharge amount is unknown.

Here, the coefficient α is determined according to the following equation according to the electrolyte temperature [when the electrolyte temperature cannot be measured directly, substitute the ambient temperature of the lead storage battery or the charger (referred to as the battery ambient temperature in this specification)]. I do.

Α = PT ² + QT + RT is the electrolyte temperature or the battery ambient temperature, and the coefficients P,
The values of Q and R were obtained by performing characteristic confirmation tests in the range of -5 to 40 ° C using various lead-acid batteries. In particular,
Coefficients P, Q and R are P = 5.56 × 10 ⁻⁴ , Q = −3.89 × 10 ⁻²
T, R = 1.67. The test results are as shown in FIG. 3, and it was found from the test results that the coefficient α was in the range between the curves A and B. Thus, the coefficient α is determined by approximating the coefficient α as an intermediate value between the curves A and B by the following equation.

Α = 5.56 × 10 ⁻⁴ T ² −3.89 × 10 ⁻² T + 1.67 The coefficient α obtained by using this equation has a value in the range of 1.0 to 1.8. As the coefficient α becomes smaller than 1.0, the battery becomes insufficiently charged. As the coefficient α becomes larger than 1.8, the battery tends to be overcharged.

After calculating the amount of discharge electricity by calculation, a method of obtaining the required amount of charge by using the amount of discharge electricity, and how to calculate the charge current based on the required amount of charge after obtaining the required amount of charge electricity The stepwise reduction is optional. As an example, the required amount of charged electricity is calculated by multiplying the amount of discharged electricity Cx by a constant coefficient β. Each time the terminal voltage reaches the current switching voltage Vo, the charging current value is reduced,
The total charge amount is obtained by integrating the charge amounts of the respective stages from the first stage to the n-th stage. Note that the minimum charging current value may be set as the charging current value. Then, the charging is stopped when the total amount of charged electricity reaches the required amount of charged electricity. Where the coefficient β
Is obtained by conducting a characteristic confirmation test using various lead-acid batteries to determine the relationship between the amount of discharged electricity and the amount of required charged electricity. From the characteristic confirmation test, it was found that the coefficient β was in the range of 1.1 to 1.3. Therefore, the coefficient β may be appropriately selected from the range of values of 1.1 to 1.3. For example, the coefficient β is set to 1.2 which is the average value of this range.
It may be. When the coefficient β approaches 1.1 and becomes smaller than this value, a tendency of insufficient charging appears, and the coefficient β becomes 1.
When the value approaches 3 and becomes larger than this value, a tendency of overcharging appears. Therefore, the value of the coefficient β may be selected in consideration of this tendency. If the required amount of charged electricity is obtained by multiplying the calculated amount of discharged electricity by a coefficient, the required amount of charged electricity can be easily obtained. Further, when charging is stopped by detecting that the total amount of charged electricity has reached the required amount of charged electricity, overcharging and insufficient charging can be reliably prevented.

The setting of the current switching voltage Vo per cell may be arbitrarily determined in consideration of conditions such as overcharging, insufficient charging, charging time, and ambient temperature of the battery. For example, when To is the ambient temperature of the lead storage battery, Vo = 2.44 + 5.58 × 10
^When determined by the formula of ⁻³ × To, the number of switching stages does not become extremely large, and good charging can be performed without causing either overcharging or insufficient charging.

A more specific method for implementing the method of the present invention is as follows. First, the terminal voltage of the lead storage battery during constant current charging is detected, and the terminal voltage is changed to the current switching voltage Vo.
The charging is performed in multiple stages using a multi-stage constant current charging method in which the charging current value is reduced each time the charging current value is reached, and after the charging current value decreases to the minimum charging current value, the charging current value stops decreasing.
The amount of charged electricity per unit time is determined at predetermined unit time intervals. Then, the first-stage charge electricity amount C1 from the start of the first-stage charge to the switching to the second-stage charge is obtained by integrating the unit-time charge electricity amounts. When the electrolyte temperature or the battery ambient temperature is T, α = 5.56 × 10 ⁻⁴ T ² −3.89 × 10 ⁻² T
The electric charge Cx at the first time is obtained by multiplying the coefficient α obtained by the equation of +1.67 by the electric charge C1 at the first time. Next, the required amount of charged electricity is calculated by multiplying the amount of discharged electricity Cx by a constant coefficient β selected from a value in the range of 1.1 to 1.3. In addition, the total charge amount is calculated by integrating the charge amounts of the first to nth stages based on the charge amount per unit time. And finally,
When the total amount of charged electricity reaches the required amount of charged electricity, charging is stopped.

[0013] When the calculation is executed based on the charge amount per unit time determined at a predetermined unit time interval, the calculation can be easily performed using a digital device such as a computer. It will be easier.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a configuration of a charging apparatus that implements the method of the present invention. In FIG. 1, reference numeral 1 denotes an AC power supply such as a commercial power supply. AC power from the AC power supply 1 is converted into DC power by a DC conversion circuit 2 including a rectifier circuit and the like. DC circuit 2
Is supplied to the power supply circuit 3. The power supply circuit 3 controls the value of the charging current supplied to the lead-acid battery 4 to a constant value, and can vary the value in multiple steps according to a variable signal. Power supply circuit. Generally, the charging current value is kept constant by adjusting the conduction angle of the current control semiconductor switch disposed between the DC conversion circuit 2 and the lead storage battery 4, and the charging current value is changed in accordance with the variable command. Is configured to change step by step.

Reference numeral 5 denotes a terminal voltage detection circuit for detecting a charge voltage of the lead storage battery, that is, a terminal voltage. This terminal voltage detection circuit 5 is constituted by, for example, a resistance voltage dividing circuit. The output of the terminal voltage detection circuit 5 is supplied to a control circuit 6 which is constituted by a microcomputer as a main calculation means and outputs a control command to the power supply circuit 3 such as changing a charging current value or stopping charging. . Reference numeral 7 denotes a current detection circuit which is constituted by, for example, a current transformer and detects a charging current value supplied to the lead-acid battery 4. The output of the current detection circuit 7 is also input to the control circuit 6. Reference numeral 8 denotes a temperature detection circuit for detecting the temperature of the lead storage battery 4 (preferably, the temperature of the electrolyte of the lead storage battery 4 or the ambient temperature of the lead storage battery). The output of the temperature detection circuit 8 is also input to the control circuit 6. I have.

The microcomputer in the control circuit 6 includes:
It operates according to a charge control program for performing the method of the present invention. In the control circuit 6, a timer for counting unit time intervals by a microcomputer is configured. The control circuit 6 normally outputs a constant current control command for performing constant current control so as to keep the charging current detected by the current detection circuit 7 constant. Then, the terminal voltage of the lead storage battery 4 during the constant current charging input from the terminal voltage detection circuit 5 is:
Each time a predetermined current switching voltage Vo is reached, a current variable command for reducing the charging current value is output. Then, after the charging current value has decreased to the predetermined minimum charging current value, the charging current value is stopped, and a charging stop command is output to stop charging when charging for the required amount of charged electricity is completed. This operation follows the charge control pattern shown in FIG.

An example of the algorithm of the charge control program for operating the microcomputer of the control circuit 6 is shown in FIG.
As shown in FIG. Hereinafter, the operation of the control circuit 6 will be described with reference to this algorithm and FIG. In this example, when detecting that the lead storage battery 4 is connected to the charger in step ST1, the charging operation is started. First, step ST
At 2, the electrolyte temperature of the lead-acid battery 4 or the battery ambient temperature (in this example, the charger ambient temperature, that is, the temperature on the circuit board on which the control circuit 6 is formed, in other words, the environmental temperature where the lead-acid battery is placed) T Is input from the temperature detection circuit 8. When the battery ambient temperature T is detected, the calculation of the coefficient α and the calculation of the current switching voltage Vo are performed by one temperature detection circuit 8.
From the detected temperature T. When the electrolytic solution temperature is used for calculating the coefficient α, the temperature detecting circuit 8 is further provided with a temperature sensor for detecting the battery ambient temperature, and inputs both the electrolytic solution temperature and the battery ambient temperature to the control circuit 6. To do.

The process of deriving the equation for calculating the coefficient α will now be described. First, in the present invention, using the initial charge electricity amount C1 from the start of the first-stage charge to the switch to the second-stage charge, the previous discharge electricity amount Cx is obtained by calculation based on the following equation (1) ( The amount of discharged electricity before calculation is called the calculated amount of discharged electricity Cx), and the required amount of charged electricity required for charging is also calculated by the following equation (2).

Calculated electric discharge amount: Cx = α × C1 (1) Required electric charge amount: Cy = β × Cx = β × α × C1 (2) Formula (1) is the calculated electric discharge amount Cx of the lead storage battery. Means that it can be calculated by multiplying the first stage charge amount C1 by the coefficient α, and the equation (2) indicates that the required charge amount Cy is multiplied by the calculated discharge amount Cx by the coefficient β, ie, the first stage Is multiplied by the coefficient α and the coefficient β. In addition, the charge amount C1 of the first stage is 1
It can be calculated by multiplying the charging time t1 of the first stage by the charging current I1 of the first stage (see FIG. 2). The second and subsequent stages can be calculated in the same manner. Therefore, equation (2) is as follows.

Required charge amount of electricity: Cy = β × α × I1 × t1 (3) The coefficient α is determined according to the following equation according to the electrolyte temperature (or the battery ambient temperature) T.

Α = PT ² + QT + R (4) where coefficients P, Q and R are −5 ° C. using various lead-acid batteries.
A characteristic confirmation test was performed in the range of ４０40 ° C. to determine a value. The test results are as shown in FIG. From this test result, it was found that the coefficient α was in the range between the curves A and B. Therefore, the coefficient α was obtained by approximation using the following equation.

Α = 5.56 × 10 ⁻⁴ T ² −3.89 × 10 ⁻² T + 1.67 (5) Therefore, the coefficients P, Q and R are P = 5.56 × 10 ⁻⁴ and Q = −3.89
× 10 ^-2 T, R = 1.67. General temperature T during charging
Is in the range of −5 ° C. to 40 ° C., and when α is obtained as a coefficient by substituting these temperatures into the above equation (5), the coefficient α is in the range of 1.0 to 1.8. Become. As the temperature T drops extremely and the coefficient α becomes smaller than 1.0, the insufficient charge occurs. As the temperature T rises extremely and becomes higher than 1.8, the battery tends to overcharge.

In this example, the coefficient β was also determined by conducting a characteristic confirmation test using various lead-acid batteries. From this test, it was found that when the above-mentioned temperature T is in the range of -5 ° C to 40 ° C, the coefficient β is preferably in the range of 1.1 to 1.3. In this example, 1.2, which is the average value of this range, is used as the coefficient β. The coefficient β is stored in the memory of the microcomputer of the control circuit 6 in advance. As the coefficient β becomes smaller than 1.2 and becomes smaller than 1.1, the tendency of insufficient charging appears, and as the coefficient β becomes larger than 1.3, the tendency of overcharging appears. From the above, the amount of electricity required for charging C
y is obtained by the following equation.

Cy = 1.2 × (5.56 × 10 ⁻⁴ T ² −3.89 × 10 ⁻² T + 1.67) × I 1 × t 1 (6)

Various methods and modes for determining the current switching voltage Vo have been proposed. In this example, when To is the ambient temperature, the current is calculated by the equation Vo = 2.44 + 5.58 × 10 ⁻³ × To. The switching voltage Vo is determined. This equation is also an equation derived based on the above-described characteristic test. Current switching voltage value V0
Is 2.55 V / cell when the ambient temperature is 20 ° C. In this example, since the battery ambient temperature T is input in step ST2, the coefficient α is set in step ST3.
And the current switching voltage Vo using the same temperature T.

Next, in step ST4, the charging current I1 for the first time, that is, the first stage, is set. In the charging method of the present invention,
The current value of the first stage is set to 0.1 to 0.2 CA, and the current values of the second and subsequent stages are gradually reduced (by 0.02 to 0.03 CA), and the minimum charging current value is set to 0.05 CA. . The first-stage current value is determined according to the charging time and the performance of the charger. If the current value of the first stage is increased, the charging time can be shortened, but the circuit must be configured to allow a large current to flow. On the other hand, if the current value of the first stage is reduced, the charging time becomes longer, but the circuit does not need to be configured to allow a large current to flow, and the circuit can be configured at low cost. In consideration of such circumstances, the current value of the first stage is set to 0.1 to
0.2 CA. Within this range, the charging time will not be too long and the price of the circuit will not be too high.

Next, in order to determine the amount of charged electricity per unit time at a predetermined unit time interval Δt, a timer is started in step ST5 to start supplying a charging current. Step S
In the constant current control routine of T6, a control command for performing constant current charging with the charging current I1 set in step ST4 is output to the power supply circuit 3. The stop current charging control in step ST6 is feedback control based on a detection value from the charging current detection circuit 7. In step ST7, the timer is counted. When it is detected in step ST8 that the count value t of the timer has reached t = Δt, in step ST9, the charge amount per unit time, that is, the unit time charge electricity amount C _Δt is calculated as C _Δt = In It is calculated by the formula of × Δt. Here, in this example,
Δt is set to one second. In is the charging current of the n-th stage.

Then, in step ST10, the total amount of charged electricity ΔC _Δt is obtained by integrating the amount of charged electricity per unit time. That is, in step ST10, ΣC _Δt = ΣC _Δt + C
The calculation of _Δt is performed. In step ST11, it is determined whether or not the charging current value is the second or subsequent stage, that is, whether or not n of In is 2 or more. If n = 1, that is, the first stage, the process proceeds to step ST12, and it is determined whether or not the terminal voltage V _{Δt of the} lead storage battery input from the terminal voltage detection circuit 5 is equal to or higher than the above-described current switching voltage Vo. Is done.
If the terminal voltage V _Δt of the lead storage battery has not become equal to or higher than the above-described current switching voltage Vo, the process proceeds to step ST13, the timer is cleared, and the process returns to step ST6.
6 to ST13 are repeated.

The result of step ST6~ST13 is repeated, if in step ST12 the terminal voltage V _{Delta] t} of the lead storage battery detects that equal to or higher than the current switching voltage Vo described above, the charging current value proceeds to step ST14 1 A determination is made as to whether or not it is a stage. If the charging current value is the first stage, the above-mentioned calculated electric discharge amount Cx = α × C1 is calculated in step ST15, and further, the necessary electric charge amount Cy is calculated.
= Β × Cx is calculated. The calculation result of step ST10, that is, the total charge amount ΣC _Δt, is used as the initial charge amount C1 from the start of the first-stage charge to the switch to the second-stage charge.

After completion of the calculation in step ST15, a step of setting n of the charging current value In to n + 1 is performed in step ST16. That is, switching of the charging current value is executed. In this example, the terminal voltage V _Δt is the current switching voltage V
o, the charging current value is reduced to 0.02-0.03C
In step ST16, the control circuit 6 issues a command to decrease A
To the power supply circuit 3. Thereafter, the process returns to step ST13, and steps ST6 to ST13 are repeated with the switched charging current value thereafter. However, when the charging current value becomes the second stage or later (n ≧ 2), step ST
The process proceeds from step 11 to step ST17 and proceeds to step ST17.
Then, it is determined whether or not the total amount of charged electricity 充電 C _Δt determined in step ST10 has reached the required amount of charged electricity Cy determined in step ST15. And the total charge amount 電 気 C _Δt
<If the required amount of electricity is Cy, the process proceeds to step ST12.

Even if the charging current becomes the second or subsequent stage, as a result of repeating steps ST6 to ST13, step ST6 is repeated.
If it is detected in step 12 that the terminal voltage _VΔt of the lead storage battery has become equal to or higher than the above-described current switching voltage Vo, step ST14
Then, it is determined whether or not the charging current value is at the first stage. In this case, since the charging current is in the second and subsequent stages, step ST15 is skipped to step ST16.
Then, further switching of the charging current is executed. Thereafter, this operation is repeated. In this example, the charging current In
Is set to 0.05 CA (minimum charging current value), the charging current value does not become 0.05 CA or less even if the current is switched in step ST16.

If it is determined in step ST17 that the total amount of charged electricity ΣC _Δt ≧ the required amount of charged electricity Cy has been detected, it is determined that the charging has been completed, the process proceeds to step ST18, and the charging operation is stopped. That is, in step ST18, a charge stop command is output from the control circuit 6 to the power supply circuit 3.

When the charging is controlled by such an algorithm, the optimum amount of charge required by the lead storage battery can be calculated by calculating the amount of discharge electricity of the lead storage battery whose discharge amount is unknown. Appropriate charging without charging and shortage is possible.

[0034]

EXAMPLE Based on the above embodiment, a charge test of a lead storage battery for an electric cart used in a golf course was conducted and examined. The method of charging a lead storage battery disclosed in Japanese Patent Application Laid-Open No. 7-78637 cannot be used because the amount of discharged electricity of a lead storage battery for an electric cart usually used at a golf course is unknown.

According to the test method, golf course A in a plain area and golf course B in a mountainous area were measured at three places in January, April and July.
The amount of discharged electricity and the amount of charged electricity of the lead storage battery of the electric cart that ran one round each time were measured. Although the amount of discharge electricity is usually unknown when used in a golf course, this time a special measurement was made to confirm the effect of the method of the present invention. Two 12V, 65Ah lead storage batteries are mounted on the electric cart.

The charging current was 0.125 CA in the first stage, and was decreased by 0.025 CA in the second and subsequent stages. However, the charging current was not smaller than 0.05 CA.
Table 1 shows the test results.

[0037]

[Table 1] Approximately 1.2 to 1.3 times the amount of normal discharged electricity is the appropriate amount of charged electricity, less than 1.2 times is insufficiently charged, and more than 1.3 times is overcharged. From this, it was found that when the method of the present invention was carried out, proper charging was possible under all conditions. Then, it was confirmed that when the method of the present invention was used, even if the amount of discharged electricity was unknown, appropriate charging could be performed according to the difference in the use environment.

[0038]

As described above, in the method for charging a lead-acid battery according to the present invention, the terminal voltage of the lead-acid battery being charged is detected, and the charging current is switched between two or several stages. In the case of using the method, even in a lead-acid battery having an unknown amount of discharged electricity, the amount of discharged electricity is calculated by multiplying the amount of charged electricity from the start of the first stage to the switching to the second stage by a coefficient determined by the electrolyte temperature. Do. Then, by calculating the required amount of charge by multiplying the calculated amount of discharged electricity by a constant coefficient, the optimal amount of charge is supplied to the lead-acid battery. There is an advantage that proper charging without charging and insufficient charging can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of a configuration of a charging apparatus that implements a method of the present invention.

FIG. 2 is a diagram showing a charging pattern when the method of the present invention is performed.

FIG. 3 is a flowchart illustrating an example of an algorithm of a charge control program for operating a microcomputer of a control circuit.

FIG. 4 is a diagram showing the results of a lead storage battery characteristic confirmation test.

[Explanation of symbols]

 Reference Signs List 1 AC power supply 2 DC conversion circuit 3 Power supply circuit 4 Lead storage battery 5 Terminal voltage detection circuit 6 Control circuit 7 Current detection circuit 8 Temperature detection circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02J 7/04 H02J 7/04 A

Claims (8)

[Claims] 1. A multi-stage current charging method for detecting a terminal voltage of a lead storage battery during constant-current charging and reducing a charging current value when the terminal voltage reaches a current switching voltage Vo, and discharging electric power before charging. Is a charging method for a lead-acid battery, in which a required amount of charged electricity is obtained based on the above, and charging is performed for the required amount of charged electricity to prevent insufficient charging and overcharging. Charge electricity C before switching to charging
1. A method for charging a lead storage battery, wherein 1 is multiplied by a coefficient α determined by an electrolyte solution temperature or a battery ambient temperature T to obtain the amount of discharged electricity Cx. 2. A method of detecting a terminal voltage of a lead storage battery during constant current charging, and using a multi-stage current charging method in which a charging current value is reduced every time the terminal voltage reaches a current switching voltage Vo. A method for charging a lead storage battery in which a required amount of charged electricity is obtained based on the amount of charge, and charging is performed by the required amount of charged electricity to prevent insufficient charging and overcharging. Is calculated by multiplying the amount of charge C1 until the switching to the charging by a coefficient α determined by the electrolyte temperature or the battery ambient temperature T, to obtain the amount of discharged electricity Cx, and multiplying the amount of discharged electricity Cx by a constant coefficient β to obtain the required amount of charged electricity. Calculating the amount of charge, integrating the amount of charge in each stage from the first stage to the n-th stage to obtain a total amount of charge, and stopping charging when the total amount of charge reaches the required amount of charge. Method of charging lead storage battery characterized by the following 3. The coefficient α is α = 5.56 × 10 ⁻⁴ T ² −3.89
The method for charging a lead storage battery according to claim 1, wherein the method is determined by an equation of × 10 ⁻² T + 1.67. 4. The method according to claim 2, wherein the coefficient β is selected from a value in a range of 1.1 to 1.3. 5. A method for detecting a terminal voltage of a lead storage battery during constant current charging, reducing a charging current value each time the terminal voltage reaches a current switching voltage Vo, and reducing the charging current value to a minimum charging current value. Is a method of charging a lead-acid battery that performs multi-stage charging using a multi-stage constant current charging method for stopping a decrease in a charging current value, wherein a unit time charging amount of electricity is obtained at a predetermined unit time interval, and The amount of charge electricity is integrated to obtain the first charge amount C1 from the start of the first-stage charge to the switch to the second-stage charge, and when the electrolyte temperature or the battery ambient temperature is T, α = 5.
56 × 10 ^-4 T ² -3.89 × 10 ^-2 T + 1.67
Is multiplied by the initial charge amount C1 to obtain a discharge amount Cx. The discharge amount Cx is multiplied by a constant coefficient β selected from a value in a range of 1.1 to 1.3 to obtain a required charge amount. Calculating the total amount of charge in each stage from the first stage to the n-th stage based on the amount of charge per unit time to obtain a total amount of charge, and the total amount of charge becomes the required amount of charge. A charging method for a lead-acid battery, wherein charging is stopped when the battery reaches the temperature. 6. The current switching voltage Vo per cell.
Is, when To is the ambient temperature, Vo = 2.44 + 5.58 ×
The method for charging a lead storage battery according to claim 2, wherein the method is determined by an equation of 10 ⁻³ × To. 7. The charging current value used for the first-stage charging is 0.1 CA to 0.2 CA, and the minimum charging current value is 0.05 CA. How to charge a lead storage battery. 8. The method according to claim 7, wherein the charging current value is reduced by 0.02 to 0.03 CA each time the terminal voltage reaches the current switching voltage.