JPH0260074A - Charging method for sealed lead-acid battery and charger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a charging method and a charging device for a sealed lead-acid battery.

[Prior Art] Conventionally, as a method for charging a sealed lead-acid battery, a normal charging 'Ki current is passed until the charging voltage reaches the final charging voltage, and when the charging voltage reaches the final charging voltage, the charging current is reduced slightly. A charging method that switches to a charging current (trickle charging method) is known. When attempting to charge a sealed lead acid battery that has been left overdischarged (hereinafter referred to as an overdischarged storage battery) using this charging method, there is a problem that if the internal resistance of the overdischarged storage battery becomes high, sufficient charging cannot be achieved. This is because when an over-discharged storage battery with a high internal resistance is charged using a conventional charging device that uses the above charging method, the charging voltage becomes higher than the final charging voltage due to the high internal resistance immediately after charging starts.
This is because the charging end voltage detector operates and the charging current is switched to a minute charging current.

In order to solve this problem, the applicant first applied a current in the opposite direction to normal charging to an overdischarged storage battery for a predetermined period of time immediately after charging started, until the battery voltage became negative. This process is referred to as reverse charging. ) proposed a method of charging a storage battery that has been left overdischarged after lowering its internal resistance (Japanese Patent Application No. 6116196).

[Problems to be Solved by the Invention] When applying the above-described charging method to an actual charging device, the problem is how to set the conditions for terminating reverse charging. In the conventional method previously proposed by the applicant, the reverse charging time is kept constant (for example, 1 hour).

However, as a result of the inventor's research, it has been found that over-discharged storage batteries differ in the effect of reverse charging depending on the ambient temperature, and the recovery of battery performance differs. This is because even if the internal resistance of the battery is the same, when the ambient temperature of the battery is low, the internal resistance decreases at a lower rate when reverse charging is performed than when the ambient temperature is high. Therefore, if reverse charging is regularly performed for a certain period of time, the internal resistance cannot be reduced even if reverse charging is performed when the ambient temperature is low, and there is a problem that over-discharged storage batteries cannot be satisfactorily charged. Ta. Further, when the ambient temperature is high, reverse charging is performed more than necessary, which prevents shortening of the charging time.

A specific example of this will be shown next. The battery used was a 4V-4^h sealed lead-acid battery with an internal resistance of 300.
Ω, and the charging characteristics when the reverse charging time is 1 hour are shown in Figure 4 (A>, (B). Figure 4 (A>
is the charging characteristic when the battery ambient humidity is 25°C, Figure 4 (B
) is the charging characteristic when the ambient temperature is 0°C. Figure 4 (
In case A), normal charging was performed smoothly after reverse charging, and trickle charging started after 8 hours and 30 minutes of normal charging.

However, in the case of FIG. 4(B), when normal charging was started after reverse charging, trickle charging immediately entered, and satisfactory charging was not performed.

From the above, it is desirable to reverse charge an over-discharged storage battery when the ambient temperature of the battery decreases.

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

[Means for Solving the Problems] In order to solve the above problems, in the method of the present invention, when charging is performed by switching the charging current to a minute charging current when the charging voltage reaches the end-of-charging voltage, the over-discharged storage battery is In contrast, in a method of charging a sealed lead-acid battery, in which a reverse voltage is applied to the battery for a predetermined period of time until the battery voltage becomes reverse polarity, and then a normal charging operation is performed, the ambient temperature of the storage battery is detected and a reverse voltage is applied. The time was varied in inverse proportion to the change in ambient temperature.

Note that in the present specification, "inversely proportional" does not mean only a case of being inversely proportional linearly, that is, a linear function, but also includes a case of being inversely proportional to a quadratic function.

Further, the charging device of the present invention uses a DC power source 1 as a charging power source that rectifies the output of an AC power source AC and outputs a DC voltage containing an AC voltage component. In order to detect the end-of-charge voltage, a charge-end voltage detector 4 is provided which detects the charging voltage of the sealed lead-acid battery B and outputs a charge-end voltage detection signal s2 when the charging voltage exceeds the charging voltage. An AC voltage component is provided to detect an AC voltage component from the charging voltage in order to detect an over-discharge left state, and when the AC voltage component is larger than a reference value, it is determined that an over-discharge left state has occurred and an AC voltage component detection signal S3 is output. A component detector 5 is provided.

When the AC voltage component detection signal S3 is output, a voltage polarity switching signal $5 and a current value switching stop signal S6 are generated for a predetermined time.
The voltage polarity switching circuit 7 outputs the current value switching command signal S1 when the charging end voltage detection signal S2 is input, but outputs the current value switching command signal S1 when the current value switching stop signal S6 is input. A current value switching control circuit 3 configured not to output S1 is provided. Furthermore, when the current value switching command signal S1 is input, the current value switching circuit 2 switches the charging current to a minute charging current;
is provided between the battery B and the polarity switching circuit (L, SWl,
SW2) is provided.

In addition to the above configuration, the present invention includes a temperature detection means for detecting the ambient temperature of the storage battery B, has a timer period that changes in inverse proportion to changes in the ambient temperature, and has a timer period that changes after the start of charging. A temperature-compatible timer circuit 6 is provided that outputs a timer signal from start to end until the timer period is completed, and the voltage polarity switching circuit 7 is configured to output a voltage polarity switching signal for a period during which the temperature-compatible timer circuit outputs the timer signal S4. s5 and a current value switching stop signal S6.

The 15-temperature compatible timer circuit 6 uses a temperature-sensitive resistance element having a negative temperature coefficient as an ambient temperature detection means, and further includes a capacitor that is charged with a constant DC voltage via the temperature-sensing resistance element, and the capacitor. It is preferable to use a voltage comparator that outputs a timer signal S4 until the charging voltage reaches a predetermined reference value.

[Function] By detecting the ambient temperature of the storage battery and changing the time to apply the reverse voltage in inverse proportion to the change in ambient temperature, the rate of decrease in internal resistance due to reverse charging of a storage battery left over-discharged is small when the ambient temperature is low. Sometimes the reverse charging time is longer to ensure that the internal resistance is lower before starting normal charging. When the ambient temperature is high and the rate of decrease in internal resistance due to reverse charging of an overdischarged storage battery is large, reverse charging for a relatively short time can prevent an increase in charging time and an increase in heat generation during charging. Therefore, according to the method of the present invention, so-called trickle charging can be reliably performed within an optimal time.

In addition, the device of the present invention focuses on the fact that when a storage battery is charged by a DC power source whose output includes an AC voltage component, the internal resistance of the battery can be detected by detecting the AC voltage component in the charging voltage. To detect. A temperature-compatible timer circuit 6 is provided in which the ambient temperature of the storage battery is detected by a temperature detection means and the timer time limit changes in inverse proportion to the detected change in the ambient temperature, and voltage polarity switching is performed based on the timer limit of the timer circuit 6. Signals S5 and S6 output from the circuit 7 to the current value switching control circuit 3 and the polarity switching circuit
By varying the output time, the reverse charging time can be varied according to the ambient temperature. Therefore, according to the device of the present invention, it is possible to control the reverse charging time reliably with a simple configuration in accordance with changes in ambient temperature.

In addition, over-discharged batteries with low internal resistance that do not require reverse charging are
Charging is performed quickly using the normal charging method without reverse charging.

[Examples] Examples 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 one embodiment of the invention. In the figure, reference numeral 1 denotes a direct current power source which transforms the output of an alternating current power source AC to a predetermined voltage using a transformer T and full-wave rectifies it using diodes Da and Db. A current value switching circuit 2 is connected to the positive output end of the DC power supply 1, which switches the charging current to a minute charging current when the current value switching signal S1 is input.

This current value switching circuit 2 inserts an impedance capable of supplying a normal charging current into the current-carrying circuit until the signal S1 is input, and when the signal S1 is input, the charging current changes to a minute charging (trickle charging) current. The charging current value is changed by inserting the impedance to be changed into the current-carrying circuit.

Switches SW1 and SW2 are provided between the current value switching circuit 2 and the sealed lead-acid battery B, and are connected to a voltage polarity switching signal S5.
Battery B is charged with reverse polarity only during the period when is output.
A polarity changeover switch circuit is configured to apply the voltage to the polarity switch circuit. These switches SW1 and SW2 are electromagnetic switches, and the coil Lk of the electromagnetic relay of the voltage polarity switching circuit 7 described below:
When current flows, contact A switches to contact S so as to apply a reverse voltage to storage battery B.

The charging end voltage detector 4 detects the charging voltage of the storage battery B, and outputs the charging end voltage detection signal S2 when the voltage reaches the charging end voltage. The AC voltage component detector 5 detects the AC voltage component of the charging voltage, and outputs an AC voltage component detection signal S3 when the voltage component is equal to or higher than a reference value. This detector 5 detects an alternating voltage component, ie, pulse vJ voltage, from the charging voltage for the purpose of detecting the internal resistance of the storage battery B.

The above reference value to be compared with the detected AC voltage component is determined by examining the relationship between the internal battery resistance and the AC voltage component in advance, and then determining the voltage value corresponding to the AC voltage component corresponding to the internal resistance that requires reverse charging. is used as the standard value.

The temperature responsive timer circuit 6 detects the ambient temperature or environmental temperature of the storage battery B using a temperature detection means having a negative temperature coefficient such as a thermistor, and changes the timer time period in inverse proportion or inverse proportion to the change in the detected temperature. It is configured with a variable timer circuit that can be and the timer circuit 6
When charging of the storage battery B is started, the timer counts the timer period and outputs the timer signal S4 until the timer period is completed. Therefore, this timer circuit 6 functions to shorten the reverse charging time as the ambient temperature increases, and to lengthen the reverse charging time as the temperature decreases.

When both the AC voltage component detection signal S3 and the timer signal S4 are input, the voltage polarity switching circuit 7 switches the timer signal S
4 is being input, a voltage polarity switching signal S5 is output to the polarity switching circuit (coil L, switches SW1 and SW2), and a current value switching stop signal S6 is output to the current value switching control circuit 3.

In principle, the current value switching control circuit 3 outputs the current value switching command signal S1 when the detection signal S2 is output from the voltage detector 4 at the end of charging, but when the current value switching stop signal S6 is input, the current value switching control circuit 3 outputs the current value switching command signal S1 at the end of charging. Detection signal S from voltage detector 4
2 is output, the current value switching command signal S1 is not output. Therefore, while the reverse voltage is being applied to the storage battery B, the current value switching circuit 2 does not switch the charging current to the minute charging current.

Next, the operation when the present invention is implemented using the apparatus shown in FIG. 1 will be described. First, in Figure 2 (A), the rating is 4■-
Ambient temperature 2 when the internal resistance becomes 300Ω with a 4^h battery
This figure shows the charging characteristics when a storage battery left over-discharged at 5° C. is charged according to the present invention. When the switch SW is closed, a charging voltage is applied to the storage battery B, but if the internal resistance is high, almost no charging current I flows, and the charging voltage V is considerably larger than the charging end voltage VS. Therefore, the charging end voltage detector 4 immediately outputs the detection signal s2 to the current value switching control circuit 3. Charging voltage V at this time
The AC voltage component of is larger than the reference value. Therefore, the AC voltage component detection signal s3 is output from the AC voltage component detector 5, and this signal is input to the voltage polarity switching circuit 7.

On the other hand, the temperature responsive timer circuit 6 outputs a timer signal S4 for a time period corresponding to the ambient temperature of the storage battery B of 25° C. (1 hour in this example).

The voltage polarity switching circuit 7 outputs the current value switching stop signal S6 and the voltage polarity switching signal s5 while the timer signal s4 is input, that is, for only one hour in this example.

While the current value switching stop signal S6 is being input, the current value switching control circuit 3 does not output the current value switching command signal S1 even if the detection signal S2 is output from the end-of-charging voltage detector 4. Therefore, the current value switching circuit 2 is maintained at an impedance that allows a normal charging current to flow.

When the voltage polarity switching circuit S5 is applied from the voltage polarity switching circuit 7 to the coil L, the switches SW1 and SW2 are switched to the contact side, and a voltage of the opposite polarity is applied to the storage battery B. Even if the above switch is switched, the voltage polarity switching circuit 7 will not be able to output the signal MS5 while the timer signal S4 is being input.
．． It is configured to continue outputting 86.

The temperature-compatible timer circuit 6 operates 1 after closing the switch SW.
After the time elapses, the output of the timer signal S4 is stopped. As a result, the output of the signals 35 and 36 from the voltage polarity switching circuit 7 is stopped, the switch SW l5W2 is switched to the contact a side, and reverse charging is completed, and the storage of electricity ii! ! A charging voltage of normal polarity is applied to R, and normal charging is performed for about 7 hours and 20 minutes. Then, when the charging voltage ■ reaches the charging end voltage VS, the charging end voltage detector 4 outputs a detection signal S2, and upon receiving this signal, the current value switching control circuit 3 transfers the current value switching signal S1 to the current value switching circuit. Output to 2. This results in
The charging current I switches to a minute charging current and enters trickle charging.

Next, Figure 2 (B) has the same rating as that in Figure 2 (A),
This figure shows the charging characteristics when an over-discharge storage battery with the same internal resistance and an ambient temperature of 0° C. is charged according to the present invention. In this case as well, the device shown in FIG. 1 operates in the same manner as described above, but the only difference is that the temperature responsive timer circuit 6 responds to the ambient temperature 0° C. of the storage battery B, and the device shown in FIG. In this example, the time is longer than in the case of ℃ 1 hour 30
minutes) is outputted as a timer signal S4. As a result, ¥77
Reverse charging of FI battery B is performed for 1 hour and 30 minutes. That is, the second
Normal charging starts after reverse charging for a longer time than in the case of Figure (A), and after about 8 hours of smooth normal charging, the charging voltage V reaches the end-of-charging voltage VSC, and the charging current I is slightly charged. [The battery has switched to trickle charging.]

As shown in 2 above, when the ambient temperature of the battery is low, by making the reverse charging time longer than when the temperature is high, normal charging is performed smoothly after the internal resistance is sufficiently reduced.
Satisfactory recovery of battery performance can be obtained.

The above describes the case of an over-discharged storage battery with high internal resistance, but in the case of an over-discharged storage battery with low internal resistance, the charging voltage is below the final charging voltage, and the AC voltage component of the charging voltage is also small. Therefore, no detection signal is output from the charging end voltage detector 4 and the AC voltage component detector 5, and normal charging is performed without reverse charging.

(Specific Embodiment) FIG. 3 shows a specific circuit configuration of the embodiment of FIG. 1 except for the DC power supply portion. In this figure, parts that are the same as those in FIG. 1 are designated by the same reference numerals as shown in FIG. 1. The current value switching circuit 2 includes resistors R1 and R2 and transistors Tr1 and Tr2. Note that the resistance values have a relationship of R1>R2. Transistor Tr1
When the transistor Tr1 is conductive, the resistor R2 and the resistor R1 are inserted in parallel to the charging circuit, and a large charging current is caused to flow. When the transistor Tr1 is cut off, a small charging current is caused to flow through the resistor R1. When the transistor Trl becomes conductive, a light emitting diode LED, which will be described next, emits light to indicate the state of charge.

The current value switching control circuit 3 is composed of transistors Tr3, Tr4 and Tr5, resistors R3 to R6, light emitting diodes LED, etc., and when neither the end-of-charging voltage detection signal S2 nor the current value switching stop signal S6 is input, the resistor R1
A base current is passed through the transistor Tr3 through
When the transistor Tr3 becomes conductive, a conduction signal is given to the transistor Tr1 of the current value switching circuit 2.

The voltage detector 4 at the end of charging is a Zener diode zoi
, a thyristor 5CR1, resistors R7 to R9, a capacitor 02, etc., and a charging voltage of Km is applied to the Zener diode ZDI while the switches SW1 and SW2 are in contact with the contact a.

When the charging voltage is higher than the charging terminal II voltage and exceeds the Zener voltage of the Zener diode ZDI, the Zener diode ZD1 becomes conductive and the thyristor 5CR1
An ignition signal is supplied to the gate of. As a result, thyristor 5CR1 becomes conductive, cutting off transistor Tr3. At this time, if the internal resistance of battery B is low and the AC voltage component detector 5 does not output the AC voltage component detection signal S3,
When the voltage polarity switching circuit 7 is not outputting the current value switching stop signal S6, the transistor Tr4 is in a non-conducting state, so the transistor Trl of the switching circuit 2 is in a cutoff state due to the cutoff of the transistor Tr3. Switch to charging with minute charging current.

When the internal resistance of battery B is large, the AC voltage component detector 5 outputs the AC voltage component detection signal S3, and the voltage polarity switching circuit 7 outputs the 'tT1 current value switching stop signal S6, so that the transistor T' Even if r4 is in a conductive state and transistor Tr3 is cut off, the transistor Trl is prevented from being cut off.

The AC voltage component detector 5 includes an operational amplifier OP2°OR3,
It is composed of a diode D4, capacitors C5 to C7, resistors R23 to R30, and the like.

Then, the DC component is subtracted from the charging voltage by the capacitor C5 and the resistor R23, and only the AC voltage component is input.

The AC voltage component amplified to a predetermined value through the operational amplifier OP2 charges the capacitor C6, and the terminal voltage of the capacitor C6 is inputted to the ten input terminal of the operational amplifier OP3 that constitutes a comparator, and is applied to the input terminal of the operational amplifier OP3 by the resistor R11 and the variable resistor VRI. The reference voltage is compared with the reference voltage output from the first reference voltage setter. This reference voltage is a voltage value that is obtained by examining the relationship between the internal resistance of the storage battery and the AC voltage component in advance and corresponds to the AC voltage component that corresponds to the internal resistance that requires reverse charging. Therefore, when the internal resistance of the battery is high enough to require reverse charging, the operational amplifier ○P3 outputs the detection signal S3.

The voltage polarity switching circuit 7 includes transistors 7r6 to Tr8,
Thyristor 5CR2, diode D2, resistor R16~R
22, a capacitor C4, a relay coil L, etc. Then, when the AC voltage component detection signal S3 is output, the thyristor 5CR2 becomes conductive, and as a result, the transistor Tr7 and the transistor Tr6 become conductive, and the transistor Tr8 becomes conductive, so that an excitation current is passed through the coil, and the switch is turned on. SW1 and SW2 switch from a contact to b contact, and a reverse voltage is applied to battery B.

The temperature-compatible timer circuit 6 includes a temperature-sensitive resistance element R13, a capacitor C3, an operational amplifier OP1, and a Zener diode ZD.
2. Resistors R10, R12 to R15, and variable resistor VR
It is composed of 2nd grade. The temperature-sensitive resistance element R13 is a resistance element whose internal resistance changes with a negative characteristic in response to changes in the ambient temperature of the storage battery B.

The temperature-sensitive resistance element R13 and the capacitor C3 constitute a temperature-responsive time constant circuit, and the terminal voltage of the capacitor C3 is determined from the reference voltage set by the second reference voltage setting device consisting of the resistor R12 and the variable resistor VR2. When becomes large, the output (timer signal 84) is no longer output from the operational amplifier OP1. The time when the operational amplifier OP1 stops outputting is the time when reverse charging stops. Until then, operational amplifier OP1
There is an output (signal 84) from the transistor T'r
As soon as transistor TrG becomes conductive, transistor TrG also becomes conductive. When the AC voltage component detector 5 outputs the signal S3 and the thyristor 5CR2 becomes conductive, the transistor Tr7
becomes conductive, transistor Tr6 also becomes conductive, and as a result, transistor TR8 becomes conductive. When the output from the operational amplifier OP1 stops, the transistor TR8 is cut off and the switches SW1 and SW2 are switched to the contact a side.

When the thyristor 5CR2 becomes conductive and the transistors Tr7 and Tr6 become conductive, a conductive signal <'RnRn is transmitted to the transistors Tr4 and Tr5 through the resistor R4 and the resistor R6.
When the haggling stop signal 86 is applied, these transistors conduct. The transistor Tr5 functions to short-circuit the anode and cathode of the thyristor 5CR1 to cut off the thyristor 5CRI during the reverse charging period. This means that when returning from reverse charging to normal charging, thyristor 5C
This is to prevent trickle charging due to a minute charging current if R1 is conductive. When the temperature corresponding time constant circuit (R13, C3) completes the time limit counting and the output of the operational amplifier OP1 disappears, the transistors Tr4, Tr5 and Tr8 are cut off and normal charging returns.

Note that in the above embodiment, the switch SW1.

Although SW2 is configured with electromagnetic switches, semiconductor switch circuits may be used as these switches.

[Effects of the Invention] According to the present invention, the time for detecting the ambient temperature of the storage battery and applying the reverse voltage is changed in inverse proportion to the change in the ambient temperature, so that when the ambient temperature is low and the over-discharged storage battery is left unused due to reverse charging. When the rate of decrease in internal resistance is small, the reverse charging time can be increased to ensure that the internal resistance is reduced before starting normal charging. Furthermore, when the ambient temperature is high and the rate of decrease in internal resistance due to reverse charging of an overdischarged storage battery is large, reverse charging for a relatively short time can prevent an increase in charging time and an increase in heat generation during charging. Therefore, according to the method of the present invention, so-called trickle charging can be reliably performed within an optimal time.

Further, according to the device of the present invention, there is provided a temperature responsive timer circuit in which the ambient temperature of the storage battery is detected by the temperature detection means and the timer period changes in inverse proportion to the detected change in the ambient temperature, and the timer period of the timer circuit is Based on this, by making the output time of the signal output from the voltage polarity switching circuit to the current value switching control circuit and the polarity switching circuit variable, the reverse charging time can be varied according to the ambient temperature. The reverse charging time can be reliably controlled with a simple configuration according to changes in temperature.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. Figure (B) is a curve diagram showing the charging characteristics when an overdischarge storage battery with a low ambient temperature is charged using the embodiment shown in Figure 1. Figure 3 is a specific circuit diagram of the embodiment shown in Figure 1. 4 (A) and (B) are uniformly applied to over-discharged storage batteries with different ambient temperatures.
FIG. 7 is a curve diagram showing an example of different charging characteristics when reverse charging is performed. 1... DC power supply, 2... Current value switching circuit, 3...
Current value switching control circuit, 4... voltage detector at the end of charging, 5
... AC voltage component detector, 6... Temperature compatible timer circuit, 7... Voltage polarity switching circuit, SWI, SW2...
・Polarity changeover switch circuit, B...Sealed lead-acid battery. 2nd cabinet (,4) W 2 ”!! (s) Figure 4 (A) Figure 4 (B)

Claims (3)

[Claims] (1) When charging is performed by switching the charging current to a minute charging current when the charging voltage reaches the final charging voltage, for over-discharged storage batteries, a reverse voltage is applied to the battery for a predetermined period of time until the battery voltage becomes reverse polarity. A method for charging a sealed lead-acid battery in which a normal charging operation is performed after application of the reverse voltage, characterized in that the ambient temperature of the storage battery is detected, and the time for applying the reverse voltage is varied in inverse proportion to the change in the ambient temperature. How to charge a sealed lead-acid battery. (2) When the charging voltage of the DC power supply 1, which rectifies the output of the AC power supply AC and outputs a DC voltage containing an AC voltage component, and the sealed lead-acid battery B is detected, and the charging voltage exceeds the final charging voltage, a charging end voltage detector 4 that outputs a charging end voltage detection signal S2; and an AC voltage component that detects an AC voltage component from the charging voltage and outputs an AC voltage component detection signal S3 when the AC voltage component is larger than a reference value. A detector 5, a voltage polarity switching circuit 7 that outputs a voltage polarity switching signal S5 and a current value switching stop signal S6 for a predetermined time when the AC voltage component detection signal S3 is output, and the voltage detection signal S2 at the end of charging. The current value switching control circuit 3 is configured to output the current value switching command signal S1 when the current value switching command signal S1 is input, but not to output the current value switching command signal S1 when the current value switching stop signal S6 is input. 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; and a current value switching circuit 2 that is provided between the current value switching circuit 2 and the storage battery B and that switches the voltage polarity. Temperature detection means for detecting the ambient temperature of the storage battery B, comprising a polarity changeover switch circuit (L, SW1, SW2) that applies the charging voltage in reverse polarity to the storage battery B only during a period when the signal S5 is output. further comprising a temperature-sensitive timer circuit 6, which has a timer time period that changes in inverse proportion to changes in the ambient temperature, and which starts counting the time period after the start of charging and outputs a timer signal until the timer time period is completed. The sealed lead-acid battery is characterized in that the voltage polarity switching circuit 7 outputs the voltage polarity switching signal S5 and the current value switching stop signal S6 during a period when the temperature corresponding timer circuit outputs the timer signal S4. charging device. (3) The temperature-compatible timer circuit 6 uses a temperature-sensitive resistance element having a negative temperature coefficient as the ambient temperature detection means, and further includes a capacitor charged by a constant DC voltage via the temperature-sensing resistance element, and a capacitor charged with a constant DC voltage through the temperature-sensitive resistance element. 3. The charging device for a sealed lead-acid battery according to claim 2, further comprising a voltage comparator that outputs the timer signal S4 until the charging voltage reaches a predetermined reference value.