JPH08317574A - Quick charger circuit - Google Patents

Abstract

PURPOSE: To provide a quick charger circuit which performs charge until full charge without causing gas generation during charging, in the quick charging of a secondary battery. CONSTITUTION: Charging is performed (S7-S11) until full charge by measuring the voltage immediately after current pulses having been put off by a voltage detection circuit, and lowering the charge current right before gas generation (S5 and S6), and elongating the off time of current pulse by a pulse waveform setting circuit at the last stage of charging, and cutting currents, and taking voltage after waiting it for a while, thereby measuring the battery voltage corresponding to the quantity of charge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quick charging circuit for rapidly charging a secondary battery.

[0002]

2. Description of the Related Art As a conventional quick charging circuit, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Laid-Open No. -1216868, a large current is supplied to the secondary battery in the initial stage of charging, and the CPU is charged during charging.
When the open circuit voltage of the rechargeable battery is measured by periodically setting the charging current to zero (off) and compared with a preset reference voltage, and it is detected that the open circuit voltage exceeds the reference voltage, It is known that charging current is switched to a low value to proceed with charging. According to this technique, it is possible to suppress the gas generation to a high charge amount and charge the battery by reducing the current before the gas generation due to the large current occurs.

Here, gas is generated when the voltage of the secondary battery exceeds a certain value. The voltage of a rechargeable battery being charged is increased by two effects: an increase in the voltage (overvoltage) corresponding to the current when an electric current is applied and an increase in the voltage due to the progress of charging and a change in the charged amount of the battery. It rises and eventually reaches a voltage at which gas evolution occurs. Therefore, at the time of rapid charging, a large current is supplied to the secondary battery and the increase in overvoltage due to the large current also increases. Therefore, as the charging progresses, the current is reduced to reduce the overvoltage before gas is generated.

Alternatively, in another charging circuit, the open circuit voltage of the secondary battery is periodically measured during charging, compared with a reference voltage, and charging is terminated when the reference voltage is exceeded.

The open circuit voltage is measured in a state where no current is passed through the secondary battery. This is because it is necessary to detect the charge state of the battery without being affected by ohmic loss due to resistance components such as battery lead wire resistance, terminal contact resistance, and battery internal resistance.

[0006]

However, in the conventional quick charging circuit, since the timing from when the charging current is zero to the measurement is not taken into consideration in the measurement of the open circuit voltage, an appropriate current switching operation is performed. There is a case where gas is generated without being performed, or a secondary battery is overcharged or insufficiently charged because an appropriate charge end operation is not performed.

To measure the open circuit voltage of the secondary battery during charging, the charging current is made to flow in pulses. The voltage of the secondary battery after the current is applied in a pulsed manner changes exponentially as shown in FIG. 6, and the overvoltage component due to the application of the current gradually decreases, and the charge amount at that time is reduced. Since the voltage approaches the corresponding voltage, the voltage measured in a short time after the pulse is cut includes the effect of voltage rise due to the overvoltage in response to the current pulse, and the voltage at the time after the pulse is cut Indicates the voltage corresponding to the increase in the charge amount.

Therefore, in order to accurately know the response of the overvoltage of the battery and appropriately change the current in order to prevent gas generation, it is necessary to set so that the voltage is detected immediately after the current is cut off. In order to prevent charging and terminate charging so that the secondary battery can be fully charged, measure the voltage after turning off the current and allowing sufficient time to obtain information on the voltage increase corresponding to the charge amount. However, in the conventional quick charge circuit, when measuring the open-circuit voltage, the timing from when the current was cut to when the voltage was measured was not taken into consideration. In some cases, the secondary battery may be overcharged or insufficiently charged without proper charging termination operation being performed.

Further, in the conventional quick charging circuit, since the above-mentioned consideration of the open circuit voltage is not taken into consideration, the measurement of the open circuit voltage can be used only for one of the current switching operation and the charge termination operation. However, it was not possible to obtain a sufficient charge amount by sequentially switching the large current without generating gas and without causing overcharge.

The present invention has been made to solve the above-mentioned problems, and provides a rapid charging circuit capable of preventing gas generation and preventing overcharge or insufficient charge of a secondary battery. It is an object.

[0011]

In order to achieve this object, a rapid charging circuit of the present invention uses a power source for generating a current for charging a secondary battery and a current pulse for switching the current from the power source to a current pulse. Current switching means for supplying to the secondary battery, voltage detecting means for detecting the voltage of the secondary battery in response to turning off of the current pulse, and current value control for changing the current value of the current pulse by the output of the voltage detecting means. Means for controlling the current switching means to change the waveform of the current pulse according to the progress of charging, and the voltage of the voltage detecting means when the waveform of the current pulse is changed by the waveform control means. And timing control means for changing the detection timing.

A judgment means for judging the end of charging based on the output of the voltage detection means may be further provided.

Further, the waveform control means is configured to change the off time of the current pulse at the end of charging longer than that at the beginning of charging, and the timing control means causes the detection timing of the voltage detecting means to be changed from that at the beginning of charging. May be configured to change slowly.

Further, the waveform control means may be configured to lower the frequency of the current pulse at the end of charging.

Further, the waveform control means may be configured to reduce the duty ratio of the current pulse at the end of charging.

[0016]

In the present invention having the above-mentioned structure, the current switching means switches the current from the power source into a current pulse and supplies the current pulse to the secondary battery, and the voltage detection means responds to the turning off of the current pulse. Detect the voltage. The current value control means is
The current value of the current pulse is changed by the output of the voltage detecting means. The waveform control means controls the current switching means to change the waveform of the current pulse according to the progress of charging, and the timing control means detects the voltage of the voltage detection means when the waveform of the current pulse is changed by the waveform control means. Change the timing.

In the case where the judging means is provided, it is possible to judge the end of charging by the output of the voltage detecting means, and to automatically or end the charging. .

Further, at the end of charging, the waveform control means changes the off time of the current pulse longer than that at the beginning of charging, and the timing control means changes the detection timing of the voltage detecting means later than at the beginning of charging. is there. For this reason, the current pulse off time is short at the beginning of charging, so charging is performed rapidly, and the detection timing of voltage detection (open circuit voltage) at this time is set relatively early after turning off and the overvoltage response is monitored. Therefore, the generation of gas is prevented. On the other hand, at the end of charging, the off time of the current pulse becomes long and the detection timing of the voltage detection (open circuit voltage) is changed to be delayed, so that the voltage when the influence of the overvoltage is eliminated can be accurately detected. It will be.

In order to prolong the off time of the current pulse, the waveform control means lowers the frequency of the current pulse at the end of charging. Therefore, the waveform of the current pulse can be easily changed, and the controllability is simplified. The same applies when the waveform control means lowers the duty ratio of the current pulse at the end of charging in order to lengthen the off time of the current pulse.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the electrical configuration of the quick charging circuit of this embodiment will be described with reference to FIG.

As shown in FIG. 1, AC power 2 is input to a constant current power supply 1 as a power supply of the present invention. The output of the constant current power supply 1 is input to the current switch circuit 3 (current switching means), and this current switch circuit 3 turns on and off the constant current of the constant current power supply 1 and applies it to the secondary battery 4 as a current pulse. is there. The current switch circuit 3 is a general one composed of a transistor switch, and its on / off is controlled by a pulse waveform setting circuit 7 described later. A current pulse is formed by this on / off control. That is, the current switch circuit 3 is configured to apply the charging current having a predetermined current value to the secondary battery 4 in the ON state and not apply the charging current in the OFF state.

Further, the constant current power source 1 has a well-known general structure, and receives an output signal from a current value setting circuit 6 which will be described later, and supplies the secondary battery 4 to the secondary battery 4 from the state of zero current at the beginning of charging. Constant current output is possible between large current values that can be applied.

The secondary battery 4 is the positive electrode of the current switch circuit 3,
It is detachably attached to the negative electrode terminal. The positive electrode of the current switch circuit 3 (the positive electrode terminal of the secondary battery 4) is
The voltage detection circuit 5 as the voltage detection means of the present invention is connected, and the voltage detection signal output terminal of the voltage detection circuit 5 is connected to the voltage detection signal input terminal of the current value setting circuit 6. Further, the voltage detection circuit 5 receives the delay time signal from the current value setting circuit 6 and sets the detection timing.

That is, the voltage detection circuit 5 measures the voltage at the positive terminal of the secondary battery 4 in response to the fall of the current pulse from the positive electrode of the current switch circuit 3 (in response to the turning off of the current pulse). Is configured to. The voltage detecting circuit 5 is a timer circuit (time measuring means) 5 for measuring the delay time indicated by the delay time signal from the turning off of the current pulse.
The voltage of the positive electrode terminal of the secondary battery 4 is measured when the delay time elapses. That is, the delay time is measured by receiving the OFF signal from the pulse waveform setting circuit 7 to be described later, and the voltage is measured when the delay time elapses.

Further, there is provided a comparison circuit (comparison means) 5b for comparing the measured voltage value with a predetermined reference voltage value. The comparison circuit 5b has a measured voltage value which is higher than the reference voltage value set by the reference voltage switching circuit 5c. Is also configured to output a voltage detection signal when it becomes high. Further, in the present embodiment, the reference voltage switching circuit 5c can set three types of the first reference voltage value, the second reference voltage value, and the third reference voltage value,
At the start of charging, the first reference voltage value is initialized, and when a voltage detection signal is output from the comparison circuit 5b in accordance with the progress of charging, it is changed to the second reference voltage value. When the detection signal is output, the reference voltage value is switched so as to be changed to the third reference voltage value. This switching is automatically performed in response to the measured voltage value becoming larger than the reference voltage value set at that time.

The current value setting circuit 6 includes a CPU and an RO.
A constant current value is commanded to the constant current power source 1 and the constant current value to be commanded is changed in response to a voltage detection signal from the comparison circuit 5b of the voltage detection circuit 5. Let That is, when the reference voltage switching circuit 5c of the voltage detection circuit 5 sets the reference voltage to the first reference voltage value, the first constant current value for instructing the maximum constant current is output to the constant current power source 1, A second constant current value smaller than the first constant current value is output when the second reference voltage value is set, and a value smaller than the second constant current value when the third reference voltage value is set. That is, the third constant current value is output.

Further, the current value setting circuit 6 outputs a delay time signal showing 4 msec as the first delay time to the timer circuit 5a of the voltage detection circuit 5 at the start of charging, and the charging progresses to cause the third circuit. When outputting the constant current value, a delay time signal indicating 49 msec as the second delay time is output to the timer circuit 5a of the voltage detection circuit 5. The output timing of the third constant current value indicates the end of charging. The current value setting circuit 6 constitutes the timing control means of the present invention.

The current value setting circuit 6 outputs a duty command signal for instructing the duty of the current pulse to the pulse waveform setting circuit 7, which is 50 m at the start of charging.
A duty command signal having an on time of sec and an off time of 5 msec is output to the pulse waveform setting circuit 7 to command the constant current power supply 1 to the first constant current value. At the end of charging, the on-time of 50 msec and 50 mse
The duty command signal for the off time of c is output to the pulse waveform setting circuit 7 to command the constant current power supply 1 to the third constant current value.

The pulse waveform setting circuit 7 receives the duty command signal and sets the count value of the built-in programmable timer for each of the ON time and the OFF time, and outputs the ON signal and the OFF signal to the current switch circuit 3 according to the time count. It outputs it. Therefore, the constant current is supplied to the secondary battery while the ON signal is output, and the constant current is not supplied to the secondary battery while the OFF signal is output. The waveform of the current pulse is changed. The current value setting circuit 6 and the pulse waveform setting circuit 7 constitute the waveform control means of the present invention.

Next, the operation of the quick charging circuit of this embodiment will be described with reference to FIGS. 1, 2, 3, 4, and 5.

When the secondary battery 4 is connected to the quick charging circuit, when the battery connection is detected by the voltage detection circuit 5 (S1; YES), charging is started. Since the charging is started, the current value setting circuit 6 outputs a command for the first constant current value (10C) to the constant current power source 1 (S2). Here, the symbol C corresponds to a current that can charge the rated capacity of the secondary battery 4 in one hour, so that the rated capacity of the secondary battery 4 is 500 m.
If Ah, the first constant current value (10C) corresponds to a current of 5A.

Next, the CPU of the current value setting circuit 6 outputs a duty command signal with an on time of 50 msec and an off time of 5 msec to the waveform setting circuit 7 (S3), and the timer circuit 5a of the voltage detection circuit 5 receives the duty command signal of 4 msec. A delay time signal indicating the first delay time is output (S4). At this time, the first reference voltage value (10C reference voltage) is set in the comparison circuit 5b of the voltage detection circuit 5 as a reference voltage value for comparison with the measured voltage value. Then, the CPU waits for the input of the voltage detection signal from the voltage detection circuit 5 (S5; NO).

Therefore, the constant current power source 1 outputs a constant current having a first constant current value (10 C), which is converted into a current pulse having an on time of 50 msec and an off time of 5 msec by the pulse waveform setting circuit 7. It is supplied to the secondary battery 4. The timer circuit 5a of the voltage detection circuit 5 receives the OFF signal from the pulse waveform setting circuit 7 and receives the delay time (4 m in this case).
The first delay time of sec) is measured, and when the time has elapsed, a trigger signal is sent to the comparison circuit 5b. Upon receiving the trigger signal, the comparison circuit 5b measures the open circuit voltage of the secondary battery 4, and outputs a voltage detection signal when the measured voltage value becomes larger than the first reference voltage value. Therefore, when the measured voltage is equal to or lower than the first reference voltage value, the voltage detection signal is not output and the reference voltage value remains the first reference voltage value.

The current pulse and the change in the positive terminal voltage of the secondary battery 4 when receiving the current pulse will be described with reference to FIG. When the current pulse is turned on, the positive terminal voltage shows a gradual increase in overvoltage after the voltage rise due to the resistance component. When the current is turned off, the voltage of the resistance component drops momentarily, then
Although the amount of overvoltage gradually decreases, the voltage at the positive electrode terminal is slightly higher than the value at the time of applying the current pulse immediately before because charging is progressing as current flows. The rechargeable battery 4 is charged by repeatedly receiving the current pulse, and accordingly, the entire voltage rises. When the voltage of the secondary battery 4 exceeds a certain value, the secondary battery 4
Since gas is generated inside, it is necessary to lower the overvoltage at the time of turning on the current pulse in order to avoid gas generation, and for that purpose, it is necessary to switch the current value to reduce the overvoltage.

The positive terminal voltage of the secondary battery 4 is measured by the voltage detection circuit 5 at the timing shown in FIG. 2 every time the current pulse is turned off, and when the current pulse of the first constant current value (10C) is applied. It is compared with the first reference voltage value (10C reference voltage), and if it is less than that, the current pulse of the first constant current value 10C is applied to the secondary battery 4 again. In the voltage detection circuit 5 of this embodiment, the voltage is measured 4 msec after the current pulse is turned off. However, the voltage may be measured in a shorter time, which is sufficient to measure the response of the overvoltage to the current pulse. If it is short, it can be set arbitrarily. The first reference voltage value (10C reference voltage) is preset to a voltage immediately before gas generation occurs in the secondary battery 4 due to an increase in overvoltage at the charging current having the first constant current value. Therefore, once the response of the overvoltage is measured, the next current pulse can be immediately supplied to the secondary battery, and the charging can be performed rapidly.

As the charging progresses, the voltage of the secondary battery 4 measured by the voltage detection circuit 5 rises, and when the voltage exceeds the first reference voltage value (10C reference voltage), the voltage is increased. The comparison circuit 5b of the detection circuit 5 outputs a voltage detection signal to the current value setting circuit 6 and this is detected (S5;
Yes). This means that the charging is completed by the current pulse having the first constant current value (10 C), and that the gas is generated inside the secondary battery when the charging is further continued.
Further, this voltage detection signal is output to the reference voltage switching circuit 5c, and in response to this signal, the reference voltage switching circuit 5c switches the reference voltage from the first reference voltage value (10C reference voltage) to the second reference voltage.

The CPU of the current value setting circuit 6 receives the voltage detection signal of the voltage detection circuit 5 and instructs the constant current power supply 1 to the second constant current value (8C) (S6), and again the voltage detection signal. Waits for input (S7; NO). Therefore, the constant current power supply 1 outputs the charging current of the second constant current value (8C),
Due to the functions of the pulse waveform setting circuit 7 and the current switch circuit 3, the ON time is 50 msec and the OFF time is 5 mse.
The rechargeable battery 4 is switched to the current pulse of c.
Is applied to

The voltage detection circuit 5 measures the voltage when the first delay time (4 msec) elapses after the current pulse is turned off, and when the measured value exceeds the second reference voltage value (8C reference voltage), the voltage detection signal is output. Is output.

Therefore, the voltage of the secondary battery 4 continues to rise as the charging further proceeds, and when the voltage exceeds the second reference voltage value, the voltage detection signal is output and the CPU of the current value setting circuit 6
When this is detected (S7; YES), the third constant current value (2C) is instructed to the constant current power supply 1 (S8). This time,
The reference voltage switching circuit 5c of the voltage detection circuit 5 is a comparison circuit 5b.
The reference voltage value is switched from the second reference voltage value (8C reference voltage) to the third reference voltage value (charging end voltage) in response to the voltage detection signal from.

Further, the CPU of the current value setting circuit 6 causes the pulse waveform setting circuit 7 to turn on for 50 msec and for 50 ms.
The duty command signal for the off time of ec is output (S
9), the voltage detection circuit 5 has a second delay time of 49 ms.
A delay time signal indicating ec is output (S10), and the voltage detection signal from the voltage detection circuit is awaited (S11; NO).

The reason for changing the waveform of the current pulse is as follows. That is, in the current of the third constant current value (2C), the overvoltage of the secondary battery 4 is higher than that of the charging with the large current such as the first constant current value (10C) or the second constant current value (8C). Does not increase, no gas is generated in the secondary battery 4 unless it is overcharged beyond the full charge. Therefore, after that, instead of monitoring overvoltage, the timing of voltage detection is delayed from the beginning of charging to accurately monitor the charge amount, and the off time is extended to measure the open-circuit voltage of the secondary battery. Of.

As described with reference to FIG. 2, the secondary battery 4 receives a current pulse, and thus exhibits an increase in overvoltage in response to the current pulse. The overvoltage at this time increases as the current pulse increases. Also, as shown in FIG. 3, the relaxation of the overvoltage exponentially decreases and, after a sufficient time, decreases to the voltage corresponding to the charge amount of the secondary battery. As described above, in the charging current pulse having the first constant current value (10C) or the second constant current value (8C), the voltage detection circuit 5 causes 4 msec (first delay time) after the current pulse is turned off.
I measured the voltage at the timing of the passage and mainly watched the change of the overvoltage due to the current pulse, but in order to monitor the voltage corresponding to the charge amount, wait a longer time after turning off the current and take the voltage. There is a need. In other words, the waveform of the current pulse before the change and the current value and the voltage detection timing were for rapid charging while preventing the generation of gas inside the secondary battery, whereas the current after the change was changed. The pulse waveform and the current value and voltage detection timing are for accurate charging.

As a result, the current having the third constant current value (2C) is converted into a current pulse having an on time of 50 msec and an off time of 50 msec, and 49 mse from the off of this current pulse.
The voltage is measured when c has elapsed, and charging is continued until the voltage exceeds the third reference voltage value (charging end voltage value). As described above, the quick charging circuit of the present embodiment lengthens the off time of the current pulse at the end of charging and further changes the timing of measuring the voltage to measure the voltage that more reflects the charge amount. The detection can be performed accurately. In the present embodiment, the voltage detection circuit 5 measures the voltage of the secondary battery 4 49 msec after the current pulse is turned off at the end of charging, but it may be measured after a longer time by extending the off time. It may be arbitrarily set within a range in which the overvoltage due to the current pulse is attenuated and the influence is reduced. On the contrary, it is possible to detect the voltage at a timing earlier than 49 msec in the range in which the overvoltage is attenuated and the influence is reduced.

When the measured voltage is lower than the third reference voltage value (charging end voltage value), the charging is continued, but as the charging progresses, the voltage rises and when it exceeds the charging end voltage value, the voltage is detected. The circuit 5 outputs to the current value setting circuit 6 a voltage detection signal indicating the end of charging. When this is detected (S11; YES), the power supply of the device is shut off and the charging is completed. This detection corresponds to the determination means of the present invention. still,
An informing device for informing that charging is completed by a display, a buzzer or the like may be provided.

The present invention is not limited to the above-mentioned embodiments, but the following modifications are possible. That is,
As the waveform control means, the current value setting circuit 6 has a pulse waveform setting circuit 7 with an ON time of 50 msec and 50 m at the end of charging.
Although the duty command signal for the off time of sec is output, a duty command signal for lowering the frequency of the current pulse can be output instead. For example, 50
It is possible to output a duty command signal indicating an ON time of 0 msec and an OFF time of 50 msec. Further, the current value setting circuit 6 can output a duty command signal for reducing the duty ratio of the current pulse to the pulse waveform setting circuit 7 at the end of charging. In this case, 5m
A duty command signal indicating the on time of sec and the off time of 50 msec may be output. In this case, the voltage measurement timing is the second delay time (49 mse).
It remains c). However, although it is already clear, when the off time is set to 50 msec or more, the delay time can be set within the range of the off time.

In this embodiment, the current value of the current pulse is changed by changing the first constant current value (10C) to the second constant current value (8
C) → 3rd constant current value (2C)
If the current value of the last supplied current pulse is the smallest and the current value is set small enough not to generate gas until fully charged, other current values and the number of change stages can be set arbitrarily. is there.

[0048]

As is apparent from the above detailed description, the rapid charging circuit of the present invention can prevent not only gas generation but also overcharge and insufficient charge of the secondary battery.
This has the effect that the time required for charging can be shortened.
Further, in the case where the determination means for determining the end of charging by the output of the voltage detection means is provided, it is possible to notify the operator of the end of charging and terminate the charging or automatically terminate the charging.

Further, when the waveform control means is at the end of charging,
When the off time of the current pulse is changed to be longer than that at the beginning of charging, and the timing control means is configured to change the detection timing of the voltage detecting means later than that at the beginning of charging, the current at the beginning of charging is changed. Since the off-time of the pulse is short, charging is performed rapidly, and the detection timing of voltage detection (open-circuit voltage) at this time is set relatively early after turning off, and the current is generated before gas is generated in the secondary battery. The current value of the pulse can be switched, and the off time of the current pulse becomes longer at the end of charging,
Since the detection timing of the voltage detection (open circuit voltage) is changed so as to be delayed, it is possible to accurately measure the charge amount and prevent overcharging or insufficient charging.

Further, when the off-time of the current pulse is reduced at the end of charging to lower the frequency of the current pulse or lower the duty ratio, the waveform of the current pulse can be easily changed and the controllability is simplified. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a quick charging circuit according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a current output and a battery voltage in an initial stage of the rapid charging circuit.

FIG. 3 is a schematic diagram illustrating a charging current pulse in a secondary battery and a voltage response of the battery.

FIG. 4 is a schematic diagram showing a current output and a battery voltage in the final stage of the quick charging circuit.

FIG. 5 is a flowchart showing an operation of a current value setting circuit.

FIG. 6 is a schematic diagram illustrating a charging current pulse in a secondary battery and a voltage response of the battery.

[Explanation of symbols]

 1 Constant current power supply 3 Current switch circuit 4 Secondary battery 5 Voltage detection circuit 6 Current value setting circuit 7 Pulse waveform setting circuit

Claims (5)

[Claims] 1. A power source for generating a current for charging a secondary battery, a current switching means for switching a current from the power source into a current pulse and supplying the current pulse to the secondary battery, and in response to turning off the current pulse. In a rapid charging circuit comprising a voltage detection means for detecting the voltage of a secondary battery and a current value control means for changing the current value of the current pulse according to the output of the voltage detection means, the current pulse according to the progress of charging. Waveform control means for controlling the current switching means so as to change the waveform of, and timing control means for changing the voltage detection timing of the voltage detection means when the waveform of the current pulse is changed by the waveform control means. Quick charging circuit characterized by. 2. The quick charging circuit according to claim 1, further comprising a determination unit that determines the end of charging based on the output of the voltage detection unit. 3. The waveform control means at the end of charging,
The off-time of the current pulse is changed to be longer than that at the beginning of charging, and the timing control unit is changed to change the detection timing of the voltage detecting unit later than that at the beginning of charging. The rapid charging circuit according to claim 1 or 2. 4. The waveform control means at the end of charging,
The quick charging circuit according to claim 3, wherein the quick charging circuit is configured to reduce the frequency of the current pulse. 5. The waveform control means at the end of charging,
The quick charging circuit according to claim 3, wherein the rapid charging circuit is configured to reduce the duty ratio of the current pulse.