A battery charging circuit and system

Abstract

The utility model discloses a battery charging circuit and system, which are connected between a charging power source and a battery. The battery charging circuit includes a shunt, an amplifying and comparing circuit, a charging control device and a charging parameter setting device; the shunt is arranged on a charging circuit where the charging power source charges the battery to obtain a judgment voltage; the amplifying and comparing circuit is connected to the shunt and the charging parameter setting device, and is used to receive the judgment voltage from the shunt, and receive the upper limit voltage and the lower limit voltage from the charging parameter setting device; the charging control device is connected to the amplifying and comparing circuit, and the amplifying and comparing circuit is also used to determine whether the judgment voltage is between the upper limit voltage and the lower limit voltage, and when the judgment voltage is not between the upper limit voltage and the lower limit voltage, a stop signal is sent to the charging control device, so that the charging control device controls the charging power source to stop charging the battery when the stop signal is received. The technical solution disclosed by the utility model can significantly enhance the charging efficiency and safety of the battery.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to a battery charging circuit and system. Background Art

[0002] With the development of energy storage technology, in the current energy storage industry, it is often necessary to use batteries for charging and discharging experiments, so the battery power needs to be replenished frequently. Charging the battery with a charging power supply is a relatively routine operation. Traditionally, people will directly connect the positive and negative terminals of the charging power supply to the positive and negative terminals of the battery through the charging line, then turn on the charging power supply, adjust the voltage of the charging power supply to make it slightly higher than the battery voltage, and then charge it with a standard current of 0.5C until the battery is fully charged.

[0003] However, as the battery voltage continues to rise, the charging current for charging the battery will continue to decrease, so that the closer the battery is to full charge, the slower the charging speed, resulting in too long a time to fully charge the battery. Here, the purpose of some experiments is to fully charge the battery, which needs to be carried out according to the manufacturer's instructions, but some experiments are to drag the batteries together, and there is no need to fully charge the batteries. Fully charging the batteries not only wastes time and electricity, but also reduces the utilization rate of the equipment, resulting in low charging efficiency of the batteries. Utility Model Content

[0004] In view of this, the utility model provides a battery charging circuit and system, the main purpose of which is to solve the technical problem of low battery charging efficiency.

[0005] To achieve the above object, the utility model first provides a battery charging circuit connected between a charging power source and a battery, wherein the battery charging circuit includes a shunt, an amplifying and comparing circuit, a charging control device, and a charging parameter setting device;

[0006] The shunt is arranged on a charging circuit for charging the battery by the charging power source, and is used to collect a judgment voltage, wherein the judgment voltage is a voltage collected by the shunt when a charging current for charging the battery by the charging power source flows through the shunt;

[0007] The amplifying and comparing circuit is connected to the shunt and the charging parameter setting device respectively, and is used to receive the judgment voltage from the shunt, and receive the preset upper limit voltage and lower limit voltage from the charging parameter setting device;

[0008] The charging control device is connected to the amplifying and comparing circuit, and the amplifying and comparing circuit is further used to determine whether the voltage value of the judgment voltage is between the voltage value of the upper limit voltage and the voltage value of the lower limit voltage, and send a charging stop signal to the charging control device when the voltage value of the judgment voltage is not between the voltage value of the upper limit voltage and the voltage value of the lower limit voltage;

[0009] The charging control device is used to control the charging power supply to stop charging the battery when receiving the charging stop signal.

[0010] In one embodiment of the utility model, the charging parameter setting device includes a first voltage source and a second voltage source, the first voltage source is used to output the upper limit voltage, and the second voltage source is used to output the lower limit voltage; the amplification comparison circuit includes a first voltage comparator and a second voltage comparator; the inverting input terminal of the first voltage comparator and the non-inverting input terminal of the second voltage comparator are connected to the shunt to receive the judgment voltage, the non-inverting input terminal of the first voltage comparator is connected to the first voltage source for receiving the upper limit voltage, and the inverting input terminal of the second voltage comparator is connected to the second voltage source for receiving the lower limit voltage; the output terminal of the first voltage comparator and the output terminal of the second voltage comparator are connected to the signal access terminal of the charging control device; the charging control device is also used to control the charging power supply to stop charging the battery when a low level signal is received from the signal access terminal.

[0011] In one embodiment of the utility model, the amplification and comparison circuit also includes a voltage amplifier; the input end of the voltage amplifier is connected to the shunt to receive the judgment voltage, and the output end of the voltage amplifier is respectively connected to the inverting input end of the first voltage comparator and the non-inverting input end of the second voltage comparator, for amplifying the judgment voltage and sending the amplified judgment voltage to the first voltage comparator and the second voltage comparator.

[0012] In one embodiment of the utility model, the battery charging circuit further includes a fuse, which is arranged on the charging circuit. When the fuse blows, the charging circuit between the charging power source and the battery is disconnected, so that the charging power source stops charging the battery.

[0013] In one embodiment of the utility model, the battery charging circuit further comprises a controlled switch;

[0014] The controlled switch is arranged on the charging circuit. When the controlled switch is turned on, the charging circuit between the charging power source and the battery is turned on. When the controlled switch is turned off, the charging circuit between the charging power source and the battery is broken and disconnected. The control end of the charging control device is connected to the controlled end of the controlled switch for controlling the controlled switch to be turned on or off.

[0015] In one embodiment of the present invention, the controlled switch is a contactor or a circuit breaker.

[0016] In one embodiment of the utility model, the battery charging circuit further includes an alarm; the alarm output end of the charging control device is connected to the controlled end of the alarm, so as to control the alarm to issue an alarm prompt information.

[0017] In one embodiment of the present invention, the alarm is a buzzer or a flash light.

[0018] In one embodiment of the present utility model, the charging control device has a human-computer interaction interface for operating the charging control device.

[0019] In addition, to achieve the above object, the utility model also provides a battery charging system, including the battery charging circuit as described above;

[0020] The battery charging system also includes a charging power source and a battery, wherein a power output end of the charging power source is connected to a power receiving end of the battery through a charging line.

[0021] The utility model provides a battery charging circuit and system, which can obtain a judgment voltage for calibrating the charging current size based on the charging current of the charging power supply for charging the battery through a shunt; here, as the charging current of the charging power supply for charging the battery decreases, the voltage value of the judgment voltage for calibrating the charging current will also decrease, and the shunt can transmit the judgment voltage to the amplification comparison circuit for subsequent comparison. Further, the relevant operator can pre-set the upper limit voltage and the lower limit voltage at the charging parameter setting device; here, when the charging power supply or the battery is short-circuited, the current on the charging line will surge, causing the judgment voltage collected by the shunt to surge, and the upper limit voltage is used to calibrate when the judgment voltage is higher than what value, it can be determined that the circuit has a short circuit fault; further, when the charging current of the battery is too low, the judgment voltage collected by the shunt will also decrease, and the lower limit voltage is used to calibrate when the judgment voltage is lower than what value, it can be determined that the charging current of the battery is too low, the charging speed is too slow, and continuing to charge will seriously reduce the charging efficiency, and the charging can be terminated at this time. Furthermore, when the amplification comparison circuit determines that the judgment voltage exceeds the upper limit voltage or is lower than the lower limit voltage, it sends a charging stop signal to the charging control device, so that the charging control device controls the charging power supply to stop charging the battery. The embodiment provided by the present application can determine the size of the charging current according to the size of the judgment voltage, and use this as a judgment basis to control the charging power supply to stop charging the battery, which not only ensures that the battery will not be damaged due to a short circuit, but also stops charging when the charging speed of the battery is too low. On the premise of meeting the experimental standards, the charging is terminated as soon as possible, thereby improving the efficiency and safety of battery charging.

[0022] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0024] Figure 1 One of the structural schematic diagrams of a battery charging circuit provided by an embodiment of the utility model is shown;

[0025] Figure 2 A schematic diagram showing the charging current characteristics of a battery provided by an embodiment of the utility model is shown;

[0026] Figure 3A second structural schematic diagram of a battery charging circuit provided by an embodiment of the utility model is shown;

[0027] Figure 4 A third structural schematic diagram of a battery charging circuit provided by an embodiment of the utility model is shown;

[0028] Figure 5 A fourth structural schematic diagram of a battery charging circuit provided in an embodiment of the utility model is shown. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0030] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0031] Combine the following Figures 1 to 5 A battery charging circuit and system according to some embodiments of the present invention are described.

[0032] like Figure 1 As shown, an embodiment of the utility model provides a battery charging circuit, which is connected between a charging power source and a battery. The charging power source can be an external DC power source, which can be controlled to operate and stop, and the positive and negative terminals of the charging power source can be connected to the positive and negative terminals of the battery through a charging line to charge the battery.

[0033] Furthermore, the battery charging circuit includes a shunt, an amplifying and comparing circuit, a charging control device and a charging parameter setting device. The charging control device can be a computing device with computing capabilities, such as a digital signal processor (DSP), an ARM chip or a single-chip microcomputer, and the charging parameter setting device is used to control the output of a preset upper limit voltage and a lower limit voltage.

[0034] Specifically, the shunt is arranged on the charging circuit for charging the battery by the charging power supply, and is used to collect the judgment voltage, wherein the judgment voltage is the voltage collected by the shunt when the charging current for charging the battery by the charging power supply flows through the shunt. Here, the shunt is an instrument for measuring direct current, and the current on the charging circuit is determined according to the voltage generated at both ends of the current collection resistor when the direct current on the charging circuit passes through the current collection resistor inside the shunt. The greater the current flowing through the shunt on the charging circuit, the greater the voltage generated at both ends of the current collection resistor. Here, the voltage at both ends of the current collection resistor inside the shunt can be directly determined as the judgment voltage, which is used to calibrate the size of the charging current.

[0035] Furthermore, the amplification and comparison circuit is connected to the shunt and the charging parameter setting device respectively, and is used to obtain the judgment voltage from the shunt and obtain the preset upper limit voltage and lower limit voltage from the charging parameter setting device. Here, the charging parameter setting device can transmit the preset upper limit voltage and the preset lower limit voltage to the amplification and comparison circuit.

[0036] Furthermore, the charging control device is connected to the amplifying and comparing circuit and the charging power supply, and the amplifying and comparing circuit is also used to determine whether the voltage value of the judgment voltage is between the voltage value of the upper limit voltage and the voltage value of the lower limit voltage, and when the voltage value of the judgment voltage is not between the voltage value of the upper limit voltage and the voltage value of the lower limit voltage, a charging stop signal is sent to the charging control device; here, the amplifying and comparing circuit may include a computing device with computing capability, which can receive the upper limit voltage and the lower limit voltage, and determine whether the judgment voltage is greater than or equal to the lower limit voltage, and less than or equal to the upper limit voltage, and when the judgment voltage is less than the lower limit voltage, or greater than the upper limit voltage, a charging stop signal is sent to the charging control device, and here, the voltage value of the upper limit voltage is greater than the voltage value of the lower limit voltage.

[0037] Furthermore, the charging control device is also used to control the charging power supply to stop charging the battery when receiving the charging stop signal. Specifically, the control output end of the charging control device is connected to the controlled end of the charging power supply to control the operating state of the charging power supply.

[0038] Furthermore, relevant staff can control the charging time of the battery by changing the lower limit voltage. Figure 2As shown, in the constant voltage region of charging, the value of the charging current gradually decreases with the increase of charging time. The relevant staff can set the value when the charging current is less than what value to stop charging. The value of the charging current can be set according to the requirements for charging time and the demand for power. For example, when the charging time is 1 hour, the charging current is C / 12. If the relevant staff hopes that the charging time is 1 hour, the lower limit voltage can be set. Here, if it is found through testing, experiments or according to the charging current characteristic curve of the battery that the charging current flowing through the charging circuit is C / 12, the judgment voltage collected by the shunt on the charging circuit is 1V, then the lower limit voltage can be set to 1V; in the actual working process, when the judgment voltage collected by the shunt on the charging circuit drops to 1V, the charging power supply is controlled to stop supplying power to control the charging time to one hour. In the above manner, the current setting can be calibrated according to the charging current characteristics of the battery. When the current setting is appropriate, the current setting device is used to control the battery charging, and the charging current and charging time are uniformly calibrated.

[0039] It should be noted that the selection of the shunt, the amplification and comparison circuit, the charging control device, and the charging parameter setting device, as well as the internal circuit connection method, can be determined according to the actual situation, and this embodiment does not make specific restrictions. In addition, the connection method of each device can be determined according to the specific selection of the device, and this embodiment does not make specific restrictions. The circuit function of the battery charging circuit provided in this embodiment is mainly realized through the circuit connection relationship between each circuit module, and does not rely on the program module in a certain circuit module. In addition, each circuit module in the battery charging circuit can be realized by an analog circuit or a digital circuit, and for the module that can be implanted with a program module, the realization of its module function can be realized by the program module provided by the prior art.

[0040] The battery charging circuit proposed in the embodiment of the utility model can obtain a judgment voltage for calibrating the charging current size based on the charging current of the charging power supply for charging the battery through the shunt; here, as the charging current of the charging power supply for charging the battery decreases, the voltage value of the judgment voltage for calibrating the charging current will also decrease, and the shunt can transmit the judgment voltage to the amplification comparison circuit for subsequent comparison. Further, the relevant operator can pre-set the upper limit voltage and the lower limit voltage at the charging parameter setting device; here, when the charging power supply or the battery is short-circuited, the current on the charging line will surge, causing the judgment voltage collected by the shunt to surge, and the upper limit voltage is used to calibrate when the judgment voltage is higher than what value, it can be determined that the circuit has a short circuit fault; further, when the charging current of the battery is too low, the judgment voltage collected by the shunt will also decrease, and the lower limit voltage is used to calibrate when the judgment voltage is lower than what value, it can be determined that the charging current of the battery is too low, the charging speed is too slow, and continuing to charge will seriously reduce the charging efficiency, and the charging can be terminated at this time. Furthermore, when the amplification comparison circuit determines that the judgment voltage exceeds the upper limit voltage or is lower than the lower limit voltage, it sends a charging stop signal to the charging control device, so that the charging control device controls the charging power supply to stop charging the battery. The embodiment provided by the present application can determine the size of the charging current according to the size of the judgment voltage, and use this as a judgment basis to control the charging power supply to stop charging the battery, which not only ensures that the battery will not be damaged due to a short circuit, but also stops charging when the charging speed of the battery is too low. On the premise of meeting the experimental standards, the charging is terminated as soon as possible, thereby improving the efficiency and safety of battery charging.

[0041] In one embodiment, Figure 3 As shown, the charging parameter setting device includes a first voltage source and a second voltage source, the first voltage source is used to output the upper limit voltage, and the second voltage source is used to output the lower limit voltage; the amplification comparison circuit includes a first voltage comparator and a second voltage comparator; wherein the first voltage source and the second voltage source can be the first voltage interface and the second voltage interface of the charging parameter setting device, so as to receive the upper limit voltage and the lower limit voltage to the charging parameter setting device respectively. Further, the charging circuit includes a positive charging line and a negative charging line, the positive charging line is connected between the positive terminal of the charging power supply and the positive receiving terminal of the battery, and the negative charging line is connected between the negative terminal of the charging power supply and the negative receiving terminal of the battery. Here, the negative charging line, the positive charging line, the battery and the charging power supply constitute a charging circuit, and here, the shunt can be set on the positive charging line or the negative charging line, which is not limited here and is also applicable to this embodiment.

[0042] Specifically, the inverting input terminal of the first voltage comparator and the non-inverting input terminal of the second voltage comparator are connected to the shunt to receive the judgment voltage, the non-inverting input terminal of the first voltage comparator is connected to the first voltage source to receive the upper limit voltage, and the inverting input terminal of the second voltage comparator is connected to the second voltage source to receive the lower limit voltage; here, the first voltage source and the second voltage source can be controlled to output a voltage of a preset voltage value, and the relevant staff can pre-set the first voltage source and the second voltage source to respectively output the upper limit voltage and the lower limit voltage. Here, the inverting input terminal of the voltage comparator can be the "-" level terminal of the voltage comparator, and the non-inverting input terminal of the voltage comparator can be the "+" level terminal of the voltage comparator.

[0043] Furthermore, the output end of the first voltage comparator is connected to the signal access end of the charging control device, and the output end of the second voltage comparator is also connected to the signal access end of the charging control device.

[0044] Further, the charging control device is also used to control the charging power supply to charge the battery when a high level signal is received from the output end of the first voltage comparator and the output end of the second voltage comparator. Further, the charging stop signal can be a low level signal output from the output end of the first voltage comparator or the output end of the second voltage comparator. Here, when the first voltage comparator outputs a low level signal to the signal access end of the charging control device, it means that the judgment voltage is higher than the upper limit voltage, and there may be a short circuit fault in the circuit, resulting in a surge in the judgment voltage. At this time, the charging power supply can be controlled to stop working; at the same time, when the second voltage comparator outputs a low level signal to the signal access end of the charging control device, it means that the judgment voltage is lower than the lower limit voltage, indicating that the charging current is too low. At this time, the charging power supply can be controlled to stop working to stop charging the battery and save charging time. Conversely, when the charging control device receives a high level signal from the output end of the first voltage comparator and the output end of the second voltage comparator, it means that there is no abnormality in the charging work and charging can continue.

[0045] The embodiments provided in the present application can compare the judgment voltage with the upper limit voltage and the lower limit voltage based on a simple circuit to determine whether a short circuit occurs in the charging circuit or whether the charging current is too small. If a short circuit occurs in the charging circuit or the charging current is too small, the charging operation is stopped, thereby ensuring the safety and efficiency of battery charging.

[0046] In one embodiment, Figure 4 As shown, the amplification and comparison circuit also includes a voltage amplifier; here, the voltage amplifier is used to amplify the received voltage to obtain an amplified voltage.

[0047] Specifically, the input end of the voltage amplifier is connected to the shunt to obtain the judgment voltage, and the output end of the voltage amplifier is respectively connected to the inverting input end of the first voltage comparator and the non-inverting input end of the second voltage comparator, for amplifying the judgment voltage and sending the amplified judgment voltage to the inverting input end of the first voltage comparator and the inverting input end of the second voltage comparator. Here, by amplifying the judgment voltage, the quality of the judgment voltage can be improved.

[0048] Furthermore, when the judgment voltage received by the first voltage comparator and the second voltage comparator is the amplified judgment voltage, the upper limit voltage and the lower limit voltage output by the first voltage source and the second voltage source also need to be amplified, and their amplification factors can refer to the amplification factors of the judgment voltage to achieve subsequent comparison work. The embodiment provided by the present application can amplify the judgment voltage collected by the shunt to make the subsequent voltage comparison work more accurate.

[0049] In one embodiment, Figure 4 As shown, the battery charging circuit also includes a fuse, which is arranged on the charging circuit. When the fuse blows, the charging circuit between the charging power source and the battery is disconnected, so that the charging power source stops charging the battery.

[0050] Specifically, the first end of the fuse can be connected to the positive terminal of the charging power supply, and the second end of the fuse can be connected to the positive receiving terminal of the battery. Further, the fuse can also be connected in series between the positive terminal of the charging power supply and the positive receiving terminal of the battery, that is, on the positive charging line, and can also be connected in series between the negative terminal of the charging power supply and the negative receiving terminal of the battery, that is, on the negative charging line. This implementation is not limited and is also applicable to this embodiment. Further, the parameters of the fuse can be determined according to actual conditions.

[0051] Furthermore, the fuse can be used as a current detection device. The embodiment provided by the present application can provide overcurrent protection for the circuit based on the fuse, thereby further improving the protection capability of the battery charging circuit and the battery.

[0052] In one embodiment, Figure 5As shown, the battery charging circuit further includes a controlled switch, which may be a contactor or a circuit breaker. Specifically, the controlled switch is arranged on the charging circuit, and when the controlled switch is turned on, the charging circuit between the charging power source and the battery is turned on, and when the controlled switch is turned off, the charging circuit between the charging power source and the battery is turned off; specifically, the controlled switch may include a first sub-switch S1 and a second sub-switch S2, and the first sub-switch S1 and the second sub-switch S2 may be contactors or circuit breakers with separation functions, respectively.

[0053] Further, the first sub-switch S1 can be set on the positive charging line, connected in series between the positive terminal of the charging power supply and the positive receiving terminal of the battery. When the first sub-switch S1 is turned on, the positive charging line realizes the electric energy exchange between the charging power supply and the battery, and when the first sub-switch S1 is turned off, the positive terminal of the charging power supply and the positive receiving terminal of the battery are disconnected. Further, the second sub-switch S2 can be set on the negative charging line, connected in series between the negative terminal of the charging power supply and the negative receiving terminal of the battery. When the second sub-switch S2 is turned on, the negative charging line realizes the electric energy exchange between the charging power supply and the battery, and when the second sub-switch S2 is turned off, the negative terminal of the charging power supply and the negative receiving terminal of the battery are disconnected. Further, the first sub-switch S1 and the second sub-switch S2 can also be set on the negative charging line and the positive charging line respectively, which is not limited here.

[0054] Furthermore, the control end of the charging control device is connected to the controlled end of the controlled switch to control the controlled switch to be turned on or off. Specifically, the control end of the charging control device can be connected to the controlled ends of the first sub-switch S1 and the second sub-switch S2, respectively, to control the turning on and off of the first sub-switch S1 and the second sub-switch S2. The embodiment provided in the present application can control the turning on and off of the controlled switch based on the charging control device. When charging the battery, if a circuit fault occurs and the charging current is greater than the maximum current value, the charging control device will be triggered to shut down the power supply and disconnect the controlled switch. Furthermore, when charging the battery, if the charging current is less than the minimum current value, the charging control device will be triggered to shut down the power supply and disconnect the circuit breaker. At this time, charging is completed, which improves the operability of the battery charging circuit.

[0055] In one embodiment, the battery charging circuit also includes an alarm, which is a buzzer or a flashlight. Specifically, the alarm output end of the charging control device is connected to the controlled end of the alarm, so as to control the alarm to issue an alarm prompt message. Furthermore, the alarm can be set in a remote control room or alarm center. When the charging control device identifies an abnormality such as a short circuit in the charging circuit, the alarm can be controlled to issue an alarm so that relevant staff can respond and handle it in time. The embodiment provided by the present application can perform abnormal alarms based on the alarm, so that relevant staff can discover the abnormality of the circuit at the first time and deal with it in time, thereby improving the safety of the battery charging circuit.

[0056] In one embodiment, the charging control device has a human-machine interaction interface for operating the charging control device. The human-machine interaction interface can be a serial port touch screen, so that relevant staff can operate and adjust the charging control device based on the human-machine interaction interface. The embodiment provided by the present application enables relevant staff to operate the charging control device based on the human-machine interaction interface, facilitates the modification of the control program in the charging control device, and controls the charging process, thereby improving the operability of the battery charging circuit.

[0057] On the other hand, an embodiment of the utility model provides a battery charging system, including the battery charging circuit as described above; further, the battery charging system also includes a charging power supply and a battery, and the power output end of the charging power supply is connected to the power receiving end of the battery through a charging circuit.

[0058] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A battery charging circuit, connected between a charging power source and a battery, characterized in that: The battery charging circuit includes a shunt, an amplification and comparison circuit, a charging control device and a charging parameter setting device; The shunt is arranged on a charging circuit for charging the battery by the charging power source, and is used to collect a judgment voltage, wherein the judgment voltage is a voltage collected by the shunt when a charging current for charging the battery by the charging power source flows through the shunt; The amplifying and comparing circuit is connected to the shunt and the charging parameter setting device respectively, and is used to receive the judgment voltage from the shunt, and receive the preset upper limit voltage and lower limit voltage from the charging parameter setting device; The charging control device is connected to the amplifying and comparing circuit, and the amplifying and comparing circuit is further used to determine whether the voltage value of the judgment voltage is between the voltage value of the upper limit voltage and the voltage value of the lower limit voltage, and send a charging stop signal to the charging control device when the voltage value of the judgment voltage is not between the voltage value of the upper limit voltage and the voltage value of the lower limit voltage; The charging control device is used to control the charging power supply to stop charging the battery when receiving the charging stop signal.

2. The battery charging circuit according to claim 1, characterized in that: The charging parameter setting device includes a first voltage source and a second voltage source, the first voltage source is used to output the upper limit voltage, and the second voltage source is used to output the lower limit voltage; the amplification comparison circuit includes a first voltage comparator and a second voltage comparator; The inverting input terminal of the first voltage comparator and the non-inverting input terminal of the second voltage comparator are connected to the shunt to receive the judgment voltage, the non-inverting input terminal of the first voltage comparator is connected to the first voltage source to receive the upper limit voltage, and the inverting input terminal of the second voltage comparator is connected to the second voltage source to receive the lower limit voltage; The output end of the first voltage comparator and the output end of the second voltage comparator are connected to the signal access end of the charging control device; The charging control device is also used to control the charging power supply to stop charging the battery when a low level signal is received from the signal access terminal.

3. The battery charging circuit according to claim 2, characterized in that: The amplification and comparison circuit also includes a voltage amplifier; The input end of the voltage amplifier is connected to the shunt to receive the judgment voltage, and the output end of the voltage amplifier is respectively connected to the inverting input end of the first voltage comparator and the non-inverting input end of the second voltage comparator, so as to amplify the judgment voltage and send the amplified judgment voltage to the first voltage comparator and the second voltage comparator.

4. The battery charging circuit according to claim 1, characterized in that: The battery charging circuit also includes a fuse, which is arranged on the charging circuit. When the fuse is blown, the charging circuit between the charging power source and the battery is disconnected, so that the charging power source stops charging the battery.

5. The battery charging circuit according to claim 1, characterized in that: The battery charging circuit also includes a controlled switch; The controlled switch is arranged on the charging circuit. When the controlled switch is turned on, the charging circuit between the charging power source and the battery is turned on. When the controlled switch is turned off, the charging circuit between the charging power source and the battery is disconnected. The control end of the charging control device is connected to the controlled end of the controlled switch and is used to control the controlled switch to be turned on or off.

6. The battery charging circuit according to claim 5, characterized in that: The controlled switch is a contactor or a circuit breaker.

7. The battery charging circuit according to claim 1, characterized in that: The battery charging circuit also includes an alarm; The alarm output terminal of the charging control device is connected to the controlled terminal of the alarm device, and is used to control the alarm device to send out alarm prompt information.

8. The battery charging circuit according to claim 7, characterized in that: The alarm device is a buzzer or a flash light.

9. The battery charging circuit according to claim 1, characterized in that: The charging control device has a human-machine interaction interface for operating the charging control device.

10. A battery charging system, characterized in that: comprising a battery charging circuit as claimed in any one of claims 1 to 9; The battery charging system also includes a charging power source and a battery, wherein a power output end of the charging power source is connected to a power receiving end of the battery through a charging line.

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