JPH0618471B2 - Sealing lead-acid battery charging method and charging device - Google Patents

Description

The present invention relates to a method for charging a sealed lead acid battery and a charging device.

[Prior Art] Conventionally, as a method of charging a sealed lead-acid battery, a normal charging current is supplied until the charging voltage reaches the terminal charging voltage, and when the charging voltage reaches the terminal charging voltage, the charging current is changed to a minute charging current. There is known a charging method (for example, a trickle charging method) for switching to. A schematic structure of an example of a conventional charging device for carrying out this charging method is as shown in FIG. This conventional device includes a DC power supply DC that rectifies an AC power supply to obtain a DC output, a current value switching circuit 10 that switches the current value of a charging current, and a charging end period that detects that the charging voltage has reached a charging end voltage. A voltage detector 20, and a current value switching control circuit 30 which outputs a current value switching command signal S1 for switching the charging current to a minute charging current to the current value switching circuit 10 when the detection signal S2 is output from the voltage detector 20. Is equipped with.

When attempting to charge a sealed lead-acid battery (hereinafter referred to as an over-discharge abandoned battery) after being left over-discharged by this device, there is a problem that the battery cannot be sufficiently charged if the internal resistance of the over-discharged battery becomes high. This is because when a conventional device charges an over-discharged battery with a high internal resistance, the charging voltage becomes higher than the end-of-charge voltage due to the high internal resistance immediately after starting charging, and the end-of-charge voltage detector 20 operates. This is because the charging current is switched to the minute charging current.

Therefore, in order to solve such a problem, the applicant first applied a current in the opposite direction to the normal charging for a predetermined period immediately after the start of charging of the over-discharged battery until the battery voltage becomes a negative state. A method has been proposed in which the battery is allowed to flow (hereinafter referred to as reverse charging), and the internal resistance of the over-discharged battery is lowered (Japanese Patent Application No. 61-16196).

[Problems to be Solved by the Invention] When the above charging method is applied to an actual charging device, a problem is how to set a condition for ending reverse charging. The simplest method for canceling the reverse charge is to uniformly set the reverse charge time (for example, 1 hour). However, even if the battery is left over-discharged, the internal resistance varies depending on the degree of over-discharged. Therefore, there are some over-discharged batteries that have very high internal resistance, some that are not very high, and some that have relatively low internal resistance. Therefore,
With the method of uniformly setting the reverse charge time, the reverse charge is insufficient for batteries with extremely high internal resistance and the recovery of the battery performance is poor, and conversely, for batteries with relatively low internal resistance, reverse charge is intentionally performed. In some cases, it is not necessary to carry out the above-mentioned operation, and the reverse charging more than necessary causes adverse effects such as an increase in charging time, an increase in heat generation during charging, and deterioration of life characteristics of the battery.

Next, a specific example of this will be shown. The battery used was a sealed lead acid battery of 4V-4Ah, and the charging characteristics when the reverse charging time was 1 hour are shown in FIGS. 8 and 9. FIG. 8 shows the charging characteristics of an over-discharged battery having an internal resistance of about 300Ω, and FIG. 9 shows the charging characteristics of an over-discharged battery having an internal resistance of about 1600Ω. In the case of FIG. 8, the normal charging is smoothly performed after the reverse charging, but in the case of FIG. 9, the normal charging from the reverse charging is resumed, and then the toicle charging is started early and the satisfactory charging is completed. Was not done. Further, the following table shows the maximum value of the battery surface temperature when the reverse charge time is changed in the over-discharged battery having the internal resistance of about 300Ω, and the longer the reverse charge time is, the more heat is generated.

Furthermore, FIG. 10 shows the cycle life characteristics after recovery of an over-discharged battery in which the battery performance has been recovered by performing normal charging after 1 hour of reverse charging. As can be seen from the figure, a battery with an internal resistance of about 10Ω has an internal resistance of about 30Ω.
Compared to a 0Ω battery, the capacity drops faster, and the life is about 150 cycles.

From the above, it is desired that the reverse charging of the over-discharged battery be performed in accordance with the actual state of the internal resistance of each battery.

An object of the present invention is to provide a charging method that solves the above-mentioned problems of the conventional technology and a charging device suitable for implementing this method.

[Means for Solving the Problems] The method of the present invention is a method for charging a sealed lead-acid battery, which performs charging by switching the charging current to a minute charging current when the charging voltage reaches the end-of-charging voltage. When the AC voltage component of the charging voltage of the storage battery is equal to or higher than a reference value using a DC power supply, a charging operation is performed to force a charging current for a predetermined charging period, and the AC voltage component is the reference during the charging period. If it does not become smaller than the value, a reverse voltage application operation of applying a reverse polarity voltage to the storage battery for a predetermined period until the battery voltage becomes a reverse polarity is performed, and the charging operation is performed until the AC voltage component becomes smaller than the reference value. The reverse voltage application operation is repeated, and when the AC voltage component becomes smaller than the reference value, the normal charging operation is performed.

Further, in the device of the present invention, a DC power supply 1 for rectifying the output of the AC power supply AC and outputting a DC voltage containing an AC voltage component.
The end-of-charge voltage detector 4 which outputs the end-of-charge voltage detection signal S2 when the charge voltage of the sealed lead-acid battery B is detected and the end-of-charge voltage exceeds the end-of-charge voltage, and the end-of-charge voltage detection signal S2 is output. Then, a hermetically sealed structure comprising a current value switching control circuit 3 which outputs a current value switching command signal S1 and a current value switching circuit 2 which switches the charging current to a minute charging current when the current value switching command signal S1 is input. In a charging device for a lead-acid battery, the above problems are solved. Therefore, in the charging device of the present invention, a polarity changeover switch which is provided between the current value changeover circuit 2 and the storage battery B and applies the charging voltage to the storage battery B in reverse polarity only during the period when the voltage polarity changeover signal S5 is output. A circuit (SW1, SW2), an AC voltage component detector 5 for detecting an AC voltage component from the charging voltage and outputting an AC voltage component detection signal S3 when the AC voltage component is larger than a reference value, and the charging voltage When the AC voltage component does not become smaller than the reference value during the predetermined charging period of positive polarity applied to the storage battery B, the voltage polarity switching signal S5 is output to the polarity switching switch circuit for the predetermined period and the voltage The flow value switching control circuit 3 is provided with a voltage polarity switching circuit 6 for outputting a current value switching stop signal S4.
Further, the current value switching control circuit 3 is configured not to output the current value switching command signal S1 when the current value switching stop signal S4 or the AC voltage component detection signal S3 is input.

[Operation of the Invention] When the ac voltage component in the charging voltage is detected in the charging of the storage battery by the DC power supply including the ac voltage component in the output,
It was found that the internal resistance of the battery can be detected.

Therefore, when the battery is charged by the method of the present invention as described above, the over-charged battery is reverse-charged for an appropriate period of time according to the degree of the internal resistance, and the internal resistance of the battery is increased. Is effectively lowered, the charging voltage becomes equal to or lower than the terminal voltage at the end of charging even if normal charging is performed later, and sufficient charging can be performed. Thereafter, as in the conventional case, when the charging voltage exceeds the terminal voltage of the charging, the charging current is switched to the minute charging current.

As described above, in the battery of which the internal resistance is not so high in the method of the present invention, it is possible to cause an increase in charging time, an increase in heat generation during charging, or a decrease in battery life due to reverse charging for a longer time than necessary. Can be prevented. Further, an over-discharged battery that does not require reverse charging and has a low internal resistance can be quickly charged by a normal charging method without performing reverse charging.

The apparatus of the present invention can implement the above method with a simple structure and without malfunction.

Embodiments Embodiments of the method and apparatus of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a schematic circuit diagram of an embodiment of the present invention. In the figure, reference numeral 1 is a rectifier circuit that rectifies the output of the AC power supply AC that has been transformed into a predetermined voltage by a transformer T. In this embodiment, this rectifier circuit is a full-wave rectifier circuit with two diodes Da and Db. It is configured. A current value switching circuit 2 that switches the charging current to a minute charging current when the current value switching command signal S1 is input is connected to the positive output terminal of the rectifier circuit 1. The current value switching circuit 2 inserts an impedance capable of supplying a normal charging current into the energizing circuit until, for example, the signal S1 is input, and when the signal S1 is input, the charging current becomes a minute charging current or a trickle charging current. The charging current value is switched by inserting the impedance to be switched into the energizing circuit.

The switches SW1 and SW2 are provided between the current value switching circuit 2 and the storage battery B, and constitute a polarity switching switch circuit for applying the charging voltage to the storage battery B in reverse polarity only during the period when the voltage polarity switching signal S5 is output. To do. These switches SW1 and SW2 are electromagnetic switches, and when a current flows through the coil L of the electromagnetic relay of the voltage polarity switching circuit 6 which will be described later, these switches make contact from the contact a so as to apply a reverse voltage to the storage battery B. Switch to b.

The end-of-charge voltage detector 4 detects the charge voltage of the sealed lead-acid battery B and outputs a end-of-charge voltage detection signal S2 when the charge voltage exceeds the end-of-charge voltage. The AC voltage component detector 5 detects the AC voltage component of the charging voltage and outputs the AC voltage component detection signal S3 when the AC voltage component is equal to or higher than the reference value. This detector 5 detects an AC voltage component, that is, a pulsating voltage component, from the charging voltage in order to detect the internal resistance of the storage battery B. Then, when the AC voltage component is detected, the reference value to be compared with the detected AC voltage component corresponds to the internal resistance that requires reverse charging, by previously examining the relationship between the internal resistance of the storage battery and the AC voltage component. The voltage value corresponding to the AC voltage component is used as the reference value.

6 is a polarity changeover switch circuit (switches SW1 and S1) for a predetermined period when the AC voltage component detection signal S3 is input.
The voltage polarity switching circuit outputs a voltage polarity switching signal S5 to W2) and a current value switching stop signal S4 to the current value switching control circuit 3.

As a general rule, the current value switching control circuit 3 outputs the current value switching command signal S1 when the terminal charging voltage detector 4 outputs the terminal charging voltage detection signal S2, but detects the current value switching stop signal S4 or the AC voltage component detection. When the signal S3 is input, even if the end-of-charge voltage detector 4 outputs the end-of-charge voltage detection signal S2, the current value switching command signal S1 is not output. Therefore, the storage battery B
While the internal resistance is high and the reverse voltage is applied to the storage battery B, the charging current is not switched to the minute charging current by the current value switching circuit 2.

Next, the operation of the apparatus shown in FIG. 1 will be described. First, FIG. 2 shows charging characteristics when an over-discharged battery having a high internal resistance was charged according to the present invention. This battery is a sealed lead-acid battery of 4V-4Ah with an internal resistance of about 300Ω. When the switch SW is closed, the charging voltage is applied to the battery B, but when the internal resistance is high, the battery is almost charged. The current I does not flow, and the charging voltage V is considerably higher than the terminal charging voltage Vs. Therefore, the end-of-charge voltage detector 4 immediately detects the end-of-charge voltage detection signal S2.
Is output to the current value switching control circuit 3. The AC voltage component of the charging voltage V at this time is considerably larger than the reference value. Therefore, the AC voltage component detector 5 also outputs the AC voltage component detection signal S3, and the detection signal S3 is input to the current value switching control circuit 3 and the voltage polarity switching circuit 6. The voltage polarity switching circuit 6 uses the above detection signal S
3 is received for a predetermined period, a predetermined period (about 15 in the embodiment)
The current value switching stop signal S4 and the voltage polarity switching signal S5 are output only for (minutes).

While the current value switching stop signal S4 or the AC voltage component detection signal S3 is input, the current value switching control circuit 3 outputs the current value switching command signal even if the signal S2 is output from the end-of-charge voltage detector 4. Do not output S1. Therefore, the current value switching circuit 2 is maintained as an impedance that allows a normal charging current to flow. When the voltage polarity switching signal S5 is applied to the coil L from the voltage polarity switching circuit 6, the switches SW1 and SW2 are switched to the contact b side, and the voltage of the reverse polarity is applied to the battery B. Even when the switches SW1 and SW2 are switched, the voltage polarity switching circuit 6 keeps the signals S4 and S5 until the preset time length period elapses.
Is configured to continue to output. In this embodiment, this period is set to a time length of about 15 minutes.
This time is the time required for the battery voltage and the battery voltage, that is, the terminal voltage, to have opposite polarities when the reverse voltage is applied, and for the internal resistance of the over-discharged battery to appropriately decrease, depending on the type and temperature of the battery. It is set appropriately.

When the above period elapses, the output of the signals S4 and S5 from the voltage polarity switching circuit 6 is stopped, the switches SW1 and SW2 are switched to the contact a side, and the charging voltage of the regular polarity is applied to the battery B. Like

However, in the case of the charging example shown in FIG.
The internal resistance of the battery B has not yet been sufficiently reduced by the reverse charge of (between minutes), and when the charging voltage of the normal polarity is applied to the battery B, the detection signal S is detected again from the AC voltage component detector 5.
3 is output. As a result, the voltage polarity switching circuit 6 operates in the same manner as described above, the reverse charging is performed again for about 15 minutes, and then the charging voltage having the normal polarity is applied to the battery B. Since the internal resistance of the battery B has become sufficiently low by these two reverse charges, the detection signal S30 is not output from the AC voltage component detector 5, and the detection signal S2 is also output from the end-of-charge voltage detector 4. There is no such thing. Therefore, after that, charging is performed in the same manner as normal charging, and when the charging voltage V reaches the end-of-charge voltage Vs, the end-of-charge voltage detector 4 outputs a detection signal S2, and the current value is received in response to this signal S2. The switching control circuit 3 outputs the current value switching signal S1 to the current value switching circuit 2. As a result, the charging current I is switched to a minute charging current, and trickle charging is started.

Next, FIG. 3 shows charging characteristics when an over-discharged battery B having the same shape as that of FIG. 2 and having an extremely high internal resistance (about 1600Ω) was charged according to the present invention.
The state where the internal resistance of the battery B decreases as expected and the normal charge is performed and then the trickle charge is started after the reverse charge of about 15 minutes is repeated four times as described above. Is shown.

FIG. 4 shows charging characteristics when an over-discharged battery having a relatively low internal resistance was charged according to the present invention.
This battery is a battery of the same shape as described above having an internal resistance of about 10Ω, and when the internal resistance is as low as this, it is possible to perform sufficiently normal charging, and therefore it is not necessary to perform reverse charging. In a battery with a small internal resistance, the charging voltage is less than the end-of-charge voltage VS and the AC voltage component is also small, so naturally the detection signals are output from the AC voltage component detector 5 and the end-of-charge voltage detector 4. No charging is performed, and normal charging is performed.

(Specific Embodiment) FIG. 5 shows a specific circuit configuration of the embodiment of FIG. 1 excluding the DC power source portion. In the figure, the same parts as those in the configuration of FIG. 1 are designated by the same reference numerals as those shown in FIG. The current value switching circuit 2 is composed of resistors R1 to R3 and transistors Tr1 and Tr2. The resistance values have a relation of R1> R2. When the transistor Tr1 is conducting, the resistor R2 and the resistor R1 are inserted in parallel in the charging circuit to allow a large charging current to flow, and when the transistor Tr1 is cut off, a minute charging current flows through the resistor R1. When the transistor Tr1 becomes conductive, a light emitting diode LED, which will be described later, emits light to display the charging state.

The current value switching control circuit 3 includes transistors Tr3 to Tr5, a light emitting diode LED, diodes D6 and D10 and a resistor R.
4 to R8, etc., and has a terminal voltage detection signal S2,
AC voltage component detection signal S3 and current value switching stop signal S4
When neither of the above is input, the base current is made to flow to the transistor Tr4 through the resistor R7 and the transistor Tr4 is
When 4 becomes conductive, a conduction signal is given to the transistor Tr1 of the current value switching circuit 2.

The end-of-charge voltage detector 4 includes a Zener diode ZD1,
A thyristor SCR1, resistors R9 to R11, a capacitor C4, etc. are provided, and a charging voltage is applied to the Zener diode ZD1. When the charging voltage is equal to or higher than the end-of-charging voltage and the charging voltage exceeds the zener voltage of the zener diode ZD1, the zener diode ZD1 becomes conductive and the ignition signal is supplied to the gate of the thyristor SCR1. As a result, the thyristor SCR1 becomes conductive and the transistor Tr4 is cut off. At this time, if the internal resistance of the battery B is low and the AC voltage component detector 5 does not output the AC voltage component detection signal S3, the transistor T
Since r3 is non-conducting, the transistor Tr
Transistor Tr of current value switching circuit 2 by shutting off 4
1 turns off and switches to charging with a small charging current.

When the internal resistance of the battery B is large, the AC voltage component detector 5 outputs the AC voltage component detection signal S3, so that the transistor Tr3 is in the conducting state and the transistor Tr4
Even if is cut off, the cutoff of the transistor Tr1 is blocked.

The AC voltage component detector 5 includes operational amplifiers OP1, OP2,
Diode D9, variable resistor VR1, capacitor C6,
It is composed of C7 and resistors R21 to R26. Then, the DC component is subtracted from the charging voltage by the capacitor C6 and the resistor R21, and only the AC voltage component is input. The AC voltage component amplified to a predetermined value through the operational amplifier OP1 is
The capacitor C7 is charged, and the terminal voltage of the capacitor C7 is input to the + input terminal of the operational amplifier OP2 forming the comparator and compared with the reference voltage output from the first reference voltage setter formed by the variable resistor VR1. To be done. This reference voltage is a voltage value corresponding to an AC voltage component corresponding to the internal resistance that needs to be reverse-charged by previously examining the relationship between the internal resistance of the storage battery and the AC voltage component. Therefore, when the internal resistance of the battery is high enough to require reverse charging, the operational amplifier OP2 outputs the detection signal S3.

When the detection signal S3 is output, the transistor Tr3 of the current value switching control circuit 3 becomes conductive and the cutoff of the transistor Tr1 is blocked.

The voltage polarity switching circuit 6 includes a capacitor charging / discharging circuit including resistors R13 and R14 and a capacitor C5, an operational amplifier OP.
3, OP4, transistor Tr6, variable resistor VR2,
It is composed of resistors R15 to R20 and a coil L of a relay.

When the AC voltage component detection signal S3 is output, the signal voltage charges the capacitor C5 through the resistor R13 with a constant time constant, and when the signal voltage disappears, the accumulated charge is discharged through the resistor R14 with a constant time constant. To be done. That is,
The rise and fall of the terminal voltage of the capacitor C5 are carried out over a predetermined time determined by the resistance values of the resistors R13 and R14 and the capacitance of the capacitor C5. By setting these times, the start timing and application period of the reverse voltage application to the battery B are set to the required conditions. FIG. 6 shows changes in the terminal voltage of the capacitor C5 when the reverse voltage application is repeated. The variable resistor VR2 constitutes a second reference voltage setting device and gives a reference voltage of a magnitude having a fixed relation to a predetermined terminal voltage of the capacitor C5 as one input of the operational amplifier OP4. Produces an output signal based on this reference voltage only while the magnitude of the input voltage is within a predetermined range. That is, the input / output relationship acts as a so-called window comparator having a hysteresis characteristic. Referring to FIG. 6, when the terminal voltage of the capacitor C5 rises to the first voltage value E1, a signal is output from the operational amplifier OP4,
This output signal continues until the terminal voltage of the capacitor C5 drops to the second voltage value E2. While this output signal is present, the transistor Tr6 is turned on, so that an exciting current is passed through the coil L, the switches SW1 and SW2 are switched, and a reverse voltage is applied to the battery B. Then, when the output from the operational amplifier OP4 is stopped, the transistor TR
6 is cut off, switches SW1 and SW2 are switched to the contact a side, and reverse charging is stopped.

On the other hand, due to the output from the operational amplifier OP4, a conduction signal (current value switching stop signal S) is sent to the transistors Tr3 and Tr5 through the resistors R5 and R8 of the current value switching control circuit 3.
4) is applied, these transistors become conductive. The transistor Tr5 keeps the thyristor SCR during the reverse charging period.
Thyristor SCR1 by shorting the anode and cathode of 1
Plays the function of shutting off. This is because if the thyristor SCR1 is conducting when the reverse charging is returned to the normal charging, trickle charging due to a minute charging current is started, and this is prevented. Operational amplifier OP4
When the output of is lost, the transistors Tr3, Tr5 and Tr6 are cut off and the normal charging is resumed.

Although the switches SW1 and SW2 are electromagnetic switches in the above embodiment, it goes without saying that semiconductor switch circuits may be used as these switches.

EFFECTS OF THE INVENTION According to the present invention, it is possible to perform reverse charging of an overdischarge left-over battery having a high internal resistance that requires reverse charging for an appropriate length of time depending on the height of the internal resistance. . This allows
In a battery whose internal resistance is not so high, it is possible to prevent increase in charging time, increase in heat generation during charging, or decrease in battery life due to reverse charging for a longer time than necessary. In addition, an over-discharged battery that does not require reverse charging and has a low internal resistance can be quickly charged by a normal charging method without performing reverse charging.

Further, the apparatus of the present invention has an advantage that the method of the present invention can be reliably performed with a simple configuration.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram showing charging characteristics when an over-discharged battery having a high internal resistance is charged in the embodiment of FIG. 1, and FIG. FIG. 4 is a diagram showing the charging characteristics when an over-discharged battery having an extremely high resistance was charged in the embodiment of FIG. 1, and FIG. 4 is a graph showing an over-discharged battery having a low internal resistance when charged in the embodiment of FIG. FIG. 5 is a diagram showing charging characteristics, FIG. 5 is a concrete circuit diagram of the embodiment shown in FIG. 1, FIG. 6 is a diagram showing changes in the capacitor voltage of the voltage polarity switching circuit in FIG. 5, and FIG. FIG. 8 is a diagram showing a schematic configuration of a charging device, FIGS. 8 and 9 are diagrams showing different examples of charging characteristics when reverse charging is uniformly performed for over-discharged batteries having different internal resistances, Figure 10 shows the battery after recovery of the battery performance after normal charging after 1 hour of reverse charging. It is a diagram showing a cycle life characteristic. 1 ... Rectifier circuit, 2 ... Current value switching circuit, 3 ... Current value switching control circuit, 4 ... End-of-charge voltage detector, 5 ... AC voltage component detector, 6 ... Voltage polarity switching circuit, SW1 , S
W2: Polarity switch circuit, B: Sealed lead acid battery.

Front page continuation (72) Inventor Kensuke Hironaka 2-1-1 Nishishinjuku, Shinjuku-ku, Tokyo Inside Shin-Kamido Electric Co., Ltd. (72) Akio Komaki 2-1-1 Nishishinjuku, Shinjuku-ku, Tokyo New Inside Kando Electric Co., Ltd.

Claims (3)

[Claims] 1. A method for charging a sealed lead-acid battery, wherein charging is performed by switching a charging current to a minute charging current when the charging voltage reaches an end-of-charging voltage, and the battery is charged by using a DC power supply containing an AC voltage component in its output. When the AC voltage component of the voltage is equal to or higher than the reference value, a charging operation is performed in which a charging current is forced to flow for a predetermined charging period, and when the AC voltage component does not become smaller than the reference value during the charging period, the battery voltage is reversed. A reverse voltage application operation of applying a reverse polarity voltage to the storage battery for a predetermined period until it becomes a polarity is performed, and the charging operation and the reverse voltage application operation are repeated until the AC voltage component becomes smaller than the reference value, and the AC voltage A method for charging a sealed lead-acid battery, comprising performing a normal charging operation when the components become smaller than the reference value. 2. A DC power supply 1 for rectifying an output of an AC power supply AC to output a DC voltage containing an AC voltage component, and a charging voltage of a sealed lead-acid battery B is detected, and the charging voltage is determined as a terminal charging voltage. An end-of-charge voltage detector 4 that outputs an end-of-charge voltage detection signal S2 when it exceeds, a current-value switching control circuit 3 that outputs a current-value switching command signal S1 when the end-of-charge voltage detection signal S2 is output, and the current In a sealed lead acid battery charging device comprising a current value switching circuit 2 for switching a charging current to a minute charging current when a value switching command signal S1 is input, the current value switching circuit 2 and the storage battery B are connected to each other. A polarity changeover switch circuit (SW1, SW2) which is provided between them and applies the charging voltage to the storage battery B in reverse polarity only during the period when the voltage polarity switching signal S5 is output, and an AC voltage component from the charging voltage. When the detected and detected AC voltage component is larger than the reference value, the AC voltage component detection signal S3
And an AC voltage component detector 5 that outputs the polarity, and the polarity for a predetermined period when the AC voltage component does not become smaller than the reference value during a predetermined charging period in which the charging voltage is positive and is applied to the storage battery B. A voltage polarity switching circuit 6 that outputs the voltage polarity switching signal S5 to the switching switch circuit and outputs a current value switching stop signal S4 to the current value switching control circuit 3 is provided, and the current value switching control circuit 3 is switched to the current Value switching stop signal S
4 or a charging device for a sealed lead storage battery, characterized in that the current value switching command signal S1 is not output when the AC voltage component detection signal S3 is input. 3. The voltage polarity switching circuit outputs the AC voltage component detection signal S output from the AC voltage component detector 5.
3, a capacitor charged with a constant time constant by 3, a capacitor discharge circuit for discharging the charge of the capacitor with a constant time constant, and a discharge voltage of the second voltage after the charge voltage of the capacitor reaches a first voltage value. 3. The sealed lead acid battery charging device according to claim 2, further comprising a window comparator circuit that outputs the voltage polarity switching signal S5 and the current value switching stop signal S4 until the voltage value of 4 is reached.