Battery pack unbalance detection circuit

Abstract

The utility model relates to the technical field of detection circuits, and discloses a battery pack unbalance detection circuit which can detect whether the battery voltage is balanced or not and is high in reliability. Comprising a charging main loop circuit (200) used for receiving or turning off a charging current input by a preceding stage, a main control circuit (300), a battery terminal connector (400), a first voltage detection circuit (500) and a second voltage detection circuit (600), the main control circuit (300) is used for receiving a first voltage signal and a second voltage signal, and the battery terminal connector (400) is used for connecting the first voltage detection circuit (500) and the second voltage detection circuit (600). The main control circuit (300) analyzes the single-cell voltage of the battery pack according to the input first voltage signal; and comparing the second voltage signal with a preset value, and when the second voltage signal is greater than the preset value, judging that the voltage of the battery pack is unbalanced according to a comparison result.

Description

Technical Field

[0001] This utility model relates to the field of detection circuit technology, and more specifically, to a battery pack imbalance detection circuit. Background Technology

[0002] Currently, most lithium battery packs only detect the total voltage of the pack during charging to determine if the pack is functioning properly. If the voltage of any cell in the pack becomes unbalanced and the circuit fails to provide timely feedback on the abnormal voltage, i.e., no voltage imbalance is addressed, the battery pack will age prematurely and become unusable.

[0003] Therefore, accurately determining whether the voltage of each battery pack is balanced and promptly addressing any imbalances has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0004] The technical problem to be solved by this utility model is to address the shortcomings of the prior art, which is that when the voltage of any cell in the battery pack is unbalanced and the circuit cannot promptly report the abnormality of the current battery voltage, i.e., no voltage imbalance processing is performed, the battery pack will age prematurely and become unusable. This utility model provides a battery pack imbalance detection circuit that can detect whether the battery voltage is unbalanced and has high reliability.

[0005] The technical solution adopted by this utility model to solve its technical problem is: to construct a battery pack imbalance detection circuit, which has the following features:

[0006] The main charging circuit is configured within the imbalance detection circuit to receive or shut off the charging current input from the previous stage.

[0007] The main control circuit receives voltage signals at its power input terminal and outputs at least three control signals. The main control circuit is equipped with preset values.

[0008] A signal output terminal of the main control circuit is connected to a signal input terminal of the charging main circuit circuit, and is used to output a first control signal.

[0009] A battery terminal connector, one of its input terminals being connected to the output terminal of the main charging circuit, is used to receive the charging current to charge the battery pack.

[0010] The first voltage detection circuit has its first input terminal connected to the output terminal of the charging main circuit, and is used to acquire the charging current, convert and divide the charging current to output a first voltage signal.

[0011] The second input terminal of the first voltage detection circuit is coupled to another signal output terminal of the main control circuit, and is used to receive the second control signal.

[0012] The signal output terminal of the first voltage detection circuit is connected to a signal input terminal of the main control circuit, which is used to receive the first voltage signal after voltage division processing.

[0013] The main control circuit analyzes the individual cell voltage of the battery pack based on the input first voltage signal;

[0014] The second voltage detection circuit has one input terminal connected to a signal terminal of the battery terminal connector, used to acquire the charging current, and to convert and divide the charging current to output a second voltage signal.

[0015] The output terminal of the second voltage detection circuit is connected to another signal input terminal of the main control circuit to receive the second voltage signal after voltage division.

[0016] The main control circuit compares the second voltage signal with the preset value. When the second voltage signal is greater than the preset value, it determines that the voltage of the battery pack is unbalanced based on the comparison result.

[0017] In some embodiments, the second voltage detection circuit includes at least a sixth MOSFET, a seventeenth resistor, and an eighteenth resistor.

[0018] The gate of the sixth MOS transistor is connected to an output terminal of the main control circuit through the nineteenth resistor.

[0019] The drain of the sixth MOS transistor is connected to one end of the seventeenth resistor.

[0020] The other end of the seventeenth resistor is connected to a signal terminal of the battery terminal connector to obtain the charging current.

[0021] The source of the sixth MOS transistor is connected to one end of the eighteenth resistor.

[0022] The other end of the eighteenth resistor is connected to another signal input terminal of the main control circuit.

[0023] In some embodiments, the second voltage detection circuit further includes a third switching diode.

[0024] The anode of the third switching diode is connected to the other end of the eighteenth resistor.

[0025] One cathode of the third switching diode is connected to a 5V power supply terminal.

[0026] The other cathode of the third switching diode is connected to the common terminal.

[0027] In some embodiments, the main control circuit includes at least a main controller.

[0028] The power input terminal of the main controller is used to receive voltage signals, and it outputs at least three control signals.

[0029] One signal output terminal of the main controller is connected to one signal input terminal of the charging main circuit, and is used to output the first control signal.

[0030] The other signal output terminal of the main controller is connected to the second input terminal of the first voltage detection circuit, and is used to output the second control signal.

[0031] One signal input terminal of the main controller is connected to the signal output terminal of the first voltage detection circuit, and is used to receive the first voltage signal after voltage division processing.

[0032] The main controller analyzes the individual cell voltage of the battery pack based on the input first voltage signal;

[0033] Another signal input terminal of the main controller is connected to one end of the eighteenth resistor, and is used to receive the second voltage signal after voltage division.

[0034] The main controller compares the second voltage signal with the preset value. When the second voltage signal is greater than the preset value, it determines that the voltage of the battery pack is unbalanced based on the comparison result.

[0035] In some embodiments, the first voltage detection circuit includes at least a fifth MOSFET, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor.

[0036] One end of the twelfth resistor is connected to the output terminal of the main charging circuit to acquire the charging current and perform conversion and voltage division on the charging current to output the first voltage signal.

[0037] The other end of the twelfth resistor is coupled to the drain of the fifth MOS transistor.

[0038] The gate of the fifth MOS transistor is connected to one end of the thirteenth resistor.

[0039] The other end of the thirteenth resistor is coupled to another signal output terminal of the main controller, and the second control signal is input to the gate of the fifth MOS transistor via the thirteenth resistor.

[0040] The source of the fifth MOS transistor is connected to one end of the fourteenth resistor.

[0041] The other end of the fourteenth resistor is connected to a signal input terminal of the main controller, and the first voltage signal is input to the main controller through the fourteenth resistor.

[0042] In some embodiments, the first voltage detection circuit further includes a second switching diode.

[0043] The anode of the second switching diode is connected to the other end of the fourteenth resistor.

[0044] One cathode of the second switching diode is connected to the 3.3V power supply terminal.

[0045] The other cathode of the second switching diode is connected to the common terminal.

[0046] In some embodiments, the charging main circuit includes at least a first MOSFET and a second MOSFET connected in series.

[0047] The drain of the first MOSFET is used to receive or turn off the charging current input from the previous stage.

[0048] The drain of the second MOSFET is connected to one input terminal of the battery terminal connector to output the charging current for charging the battery pack.

[0049] The source of the first MOSFET and the source of the second MOSFET are connected.

[0050] The gates of the first MOSFET and the second MOSFET are connected.

[0051] In some embodiments, the charging main circuit 200 further includes a third MOSFET and a fourth MOSFET.

[0052] The gate of the third MOS transistor is connected to a signal output terminal of the main controller through a fourth resistor.

[0053] The drain of the third MOS transistor is connected to the gates of the first MOS transistor and the second MOS transistor respectively through a third resistor.

[0054] The source of the third MOS transistor is connected to the drain of the fourth MOS transistor.

[0055] The gate of the fourth MOS transistor is connected to a signal output terminal of the main controller through a seventh resistor.

[0056] The source of the fourth MOS transistor is connected to the common terminal.

[0057] The battery pack imbalance detection circuit of this invention includes a main charging circuit for receiving or shutting off the charging current input from the previous stage, a main control circuit, a battery terminal connector, a first voltage detection circuit, and a second voltage detection circuit. The main control circuit receives a first voltage signal and a second voltage signal. It analyzes the voltage of a single cell in the battery pack based on the input first voltage signal and compares the second voltage signal with a preset value. When the second voltage signal is greater than the preset value, the circuit determines that the battery pack voltage is unbalanced based on the comparison result. Compared with existing technologies, by connecting a circuit to the battery terminal to detect battery voltage and then determining whether the average voltage of the first and second voltage signals is balanced, the circuit can proactively prevent or address battery pack imbalances. This effectively solves the problem that when the voltage of any cell in the battery pack is unbalanced, and the circuit cannot promptly report the abnormal battery voltage, the battery pack may age prematurely and become unusable. Attached Figure Description

[0058] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0059] Figure 1 This is a circuit schematic diagram of an embodiment of the LDO circuit provided by this utility model;

[0060] Figure 2 This is a circuit diagram of an embodiment of the charging main circuit circuit, battery terminal connector and first voltage detection circuit provided by this utility model;

[0061] Figure 3 This is a circuit schematic diagram of an embodiment of the main control circuit provided by this utility model;

[0062] Figure 4 This is a circuit diagram of an embodiment of the second voltage detection circuit provided by this utility model. Detailed Implementation

[0063] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0064] like Figures 1-4 As shown, in the first embodiment of the battery pack imbalance detection circuit of this utility model, the battery pack imbalance detection circuit 10 includes an LDO circuit 100, a charging main circuit 200, a main control circuit 300, a battery terminal connector 400, a first voltage detection circuit 500, and a second voltage detection circuit 600.

[0065] The LDO circuit 100 is used to output a 3.3V voltage to provide a 3.3V operating power supply for the main control circuit 300.

[0066] The charging main circuit 200 is used to control the opening and closing of the charging current. When the charging is abnormal or fully charged, the charging main circuit 200 switches from being on to being off according to the control signal input from the main control circuit 300, thereby cutting off the charging current.

[0067] The main control circuit 300 has the functions of signal processing, calculation, signal comparison, detection and output of multiple control signals. It communicates with the battery pack and performs information exchange between the charger and the battery pack.

[0068] The battery terminal connector 400 is a terminal connector CN101 for a battery pack (not shown), which is connected to the battery pack and mainly consists of terminals such as B+, COM, B3, and B-.

[0069] The battery voltage detection terminal (corresponding to B+) of the first voltage detection circuit 500, i.e. the voltage detection of batteries 1-5, performs voltage division processing on the detected current signal and then outputs the first voltage signal accordingly.

[0070] The battery voltage detection terminal (corresponding to B3) of the second voltage detection circuit 600, which detects the voltage of batteries 1-3, performs voltage division processing on the detected current signal and then outputs the corresponding second voltage signal.

[0071] Specifically, the main charging circuit 200 is configured within the imbalance detection circuit to receive or shut off the charging current input from the preceding charging circuit.

[0072] When the charging main circuit 200 is turned on, the charging current is output through the charging main circuit 200 to one end of the battery terminal connector 400 (corresponding to "B+").

[0073] Furthermore, the power input terminal of the main control circuit 300 is connected to the output terminal of the LDO circuit 100 to receive the 3.3V voltage signal output by the LDO circuit 100 and provide it with operating power.

[0074] The main control circuit 300 outputs at least three control signals, namely...

[0075] First control signal, second control signal, and third control signal

[0076] The main control circuit has a preset value, which is the voltage error value for each section, and can be set to ±50mV;

[0077] A signal output terminal of the main control circuit 300 is connected to a signal input terminal of the charging main circuit 200. The main control circuit 300 inputs a first control signal to the charging main circuit 200, which is used to control the on / off state of the charging main circuit 200.

[0078] Furthermore, one input terminal of the battery terminal connector 400 is connected to the output terminal of the charging main circuit circuit 200 to receive the charging current output when the charging main circuit circuit 200 is controlled to be turned on, so as to charge the battery pack.

[0079] The first input terminal of the first voltage detection circuit 500 is connected to the output terminal (corresponding to the B+ terminal) of the charging main circuit 200. This circuit is used to acquire the charging current output when the charging main circuit 200 is controlled to be turned on, and to convert and divide the acquired charging current to output a first voltage signal.

[0080] Furthermore, the second input terminal of the first voltage detection circuit 500 is coupled to another signal output terminal of the main control circuit 300, and is used to receive a second control signal, which is used to control the on / off state of the first voltage detection circuit 500.

[0081] Furthermore, the signal output terminal of the first voltage detection circuit 500 is connected to a signal input terminal of the main control circuit 300, which is used to receive the first voltage signal after voltage division processing.

[0082] The main control circuit 300 analyzes the individual cell voltage of the battery pack based on the input first voltage signal;

[0083] Specifically, when the first voltage detection circuit 500 is controlled to be turned on, it is used to obtain the charging current output when the charging main circuit circuit 200 is controlled to be turned on, and to convert and divide the obtained charging current, and output the first voltage signal to the main control circuit 300. The main control circuit 300 performs calculations on the input first voltage signal to obtain the voltage of "B+", that is, the sum of the voltages of CELL1 to CELL5 batteries. Then, through internal calculations of the main control circuit 300, the single-cell voltage of "B+" voltage / 5 = V (1-5) is obtained.

[0084] Furthermore, an input terminal of the second voltage detection circuit 600 is connected to a signal terminal (corresponding to terminal B3) of the battery terminal connector 140, used to acquire the charging current output when the charging main circuit circuit 200 is controlled to be turned on, and to convert and divide the input charging current to output a second voltage signal to the main control circuit 300.

[0085] The output terminal of the second voltage detection circuit 600 is connected to another signal input terminal of the main control circuit 300 to receive the second voltage signal after voltage division.

[0086] The main control circuit 300 compares the input second voltage signal with a preset value. When the second voltage signal is greater than the preset value, the main control circuit 300 determines that the battery pack voltage is unbalanced based on the comparison result.

[0087] Using this technical solution, by connecting a circuit to the battery terminals to detect the battery voltage, and then the main control circuit 300 to determine whether the average value of the first voltage signal and the second voltage signal of the battery is balanced, when the voltage of the battery pack is unbalanced, the imbalance of the battery pack can be prevented or dealt with in advance. This effectively solves the problem that when the voltage of any cell in the battery pack is unbalanced, and the circuit cannot promptly report the abnormality of the current battery voltage, the battery pack will age prematurely and become unusable.

[0088] In some implementations, such as Figure 4 As shown, to obtain accurate charging current, a sixth MOSFET Q601, a seventeenth resistor R601, and an eighteenth resistor R602 can be set in the second voltage detection circuit 600. The sixth MOSFET Q601 is an N-channel enhancement-mode MOSFET, which functions as a switch.

[0089] The seventeenth resistor R601 is a sampling resistor used to obtain the current signal from one end (corresponding to the B+ end) of the battery terminal connector 400. It then works with the twenty-first resistor R605 to perform voltage division on the input charging current signal to output the second voltage signal.

[0090] The eighteenth resistor, R602, is the output resistor;

[0091] Specifically, the gate of the sixth MOSFET Q601 is connected to an output terminal (corresponding to the B3-ENABLE terminal) of the main control circuit 300 through the nineteenth resistor R603, and is used to receive the first control signal output by the main control circuit 300.

[0092] Furthermore, the drain of the sixth MOSFET Q601 is connected to one end of the seventeenth resistor R601, and the other end of the seventeenth resistor R601 is connected to a signal terminal (corresponding to the B+ terminal) of the battery terminal connector 400 to obtain the charging current.

[0093] The source of the sixth MOSFET Q601 is connected to one end of the eighteenth resistor R602.

[0094] The other end of the eighteenth resistor R602 is connected to another signal input terminal of the main control circuit 300.

[0095] Specifically, when the first control signal output by the main control circuit 300 is high, the sixth MOSFET Q601 is turned on, and the current signal at one end of the battery terminal connector 400 (corresponding to the B3 end) is output to the main control circuit 300 through the seventeenth resistor R601, the sixth MOSFET Q601 and the eighteenth resistor R602, and then compared with the preset value in the main control circuit 300.

[0096] In some implementations, such as Figure 4 As shown, the second voltage detection circuit 600 also includes a third switching diode D601.

[0097] In this configuration, the anode of the third switching diode D601 is connected to the other end of the eighteenth resistor R602.

[0098] One cathode of the third switching diode D601 is connected to the 5V power supply terminal.

[0099] The other cathode of the third switching diode D601 is connected to the common terminal.

[0100] In some implementations, such as Figure 3 As shown, in order to improve the performance of the detection circuit, a main controller U301, a voltage regulator module 320 and a display module 330 can be set in the main control circuit 300. These modules have the functions of calculation, signal processing, signal comparison and output of multiple control signals.

[0101] Specifically, the power input terminal (corresponding to pin 9) of the main controller U301 is connected to the output terminal of the LDO circuit 100 to receive the 3.3V voltage signal output by the LDO circuit 100, and it outputs at least three control signals.

[0102] Specifically, a signal output terminal (corresponding to pin 12) of the main controller U301 is connected to a signal input terminal of the charging main circuit 200, and is used to output a first control signal to the charging main circuit 200.

[0103] The other signal output terminal (corresponding to pin 2) of the main controller U301 is connected to the second input terminal of the first voltage detection circuit 500, and is used to output a second control signal to the first voltage detection circuit 500.

[0104] One signal input terminal (corresponding to pin 1) of the main controller U301 is connected to the signal output terminal of the first voltage detection circuit 500 to receive the first voltage signal after voltage division.

[0105] The main controller U301 analyzes the individual cell voltage of the battery pack based on the input first voltage signal;

[0106] Furthermore, another signal input terminal of the main controller U301 (corresponding to pin 19) is connected to one end of the eighteenth resistor R602 to receive the second voltage signal after voltage division.

[0107] The main controller U301 compares the second voltage signal with a preset value. When the second voltage signal is greater than the preset value, it determines that the battery pack voltage is unbalanced based on the comparison result.

[0108] The input terminal of the voltage regulator module 320 is connected to the output terminal of the LDO circuit 100, and the output terminal of the voltage regulator module 320 is connected to a signal input terminal (corresponding to pin 3) of the main controller U301.

[0109] The input terminals of the display module 330 are connected to the signal output terminals (corresponding to pins 14 and 16) of the main controller U301, and the current working status (charging / unbalanced) is displayed by the LED lights of the display module 330.

[0110] Specifically, the voltage “B3” is obtained by voltage division between the seventeenth resistor R601 and the twenty-first resistor R605, and is sent to the main controller U301 for calculation through the eighteenth resistor R602 and the network “B3_AD”. The result is that the voltage of “B3” is the sum of the voltages of CELL1~CELL3 batteries, that is, “B3” voltage / 3 = V(1-3) single cell voltage, (”B+” - “B3”) / 2 = V(4-5) single cell voltage;

[0111] The main controller U301 makes comparisons. When V(1-5) = V(1-3) = V(4-5), the voltage error of each section is ±50mV. If the error value is exceeded, it means that the voltage is unbalanced.

[0112] In some implementations, such as Figure 2 As shown, to obtain accurate charging current, a fifth MOSFET Q501, a twelfth resistor R501, a thirteenth resistor R502, and a fourteenth resistor R503 can be set in the first voltage detection circuit 500. Among them, the fifth MOSFET Q501 is selected as an N-channel enhancement-mode MOSFET, which has the function of a switch.

[0113] The twelfth resistor, R501, is a sampling resistor.

[0114] Specifically, one end of the twelfth resistor R501 is connected to the output terminal (corresponding to B+) of the charging main circuit circuit 200, and is used to obtain the charging current output when the charging main circuit circuit 200 is controlled to be turned on, and to convert and divide the input charging current to output a second voltage signal to the main controller U301.

[0115] The other end of the twelfth resistor R501 is coupled to the drain of the fifth MOSFET Q501.

[0116] The gate of the fifth MOSFET Q501 is connected to one end of the thirteenth resistor R502.

[0117] The other end of the thirteenth resistor R502 is coupled to another signal output terminal (corresponding to pin 2) of the main controller U301. The second control signal is input to the gate of the fifth MOSFET Q501 through the thirteenth resistor R502.

[0118] The source of the fifth MOSFET Q501 is connected to one end of the fourteenth resistor R503.

[0119] The other end of the fourteenth resistor R503 is connected to a signal input terminal (corresponding to pin 1) of the main controller U301, and the first voltage signal is input to the main controller U301 through the fourteenth resistor R503.

[0120] Specifically, when the second control signal output by the main controller U301 is high, the fifth MOSFET Q501 is turned on, and the current signal of one end of the battery terminal connector 400 (corresponding to the B+ end) is output to the main controller U301 through the twelfth resistor R501, the fifth MOSFET Q501 and the fourteenth resistor R503, and then processed by the main controller U301.

[0121] Specifically, the voltage at the "B+" terminal is obtained by voltage division by the twelfth resistor R501 and the fifteenth resistor R504, and then sent to the main controller U301 for processing via the fourteenth resistor R503 and the network "VSTACK_AD". The result is the voltage at the "B+" terminal, which is the sum of the voltages of CELL1 to CELL5. The main controller U301 calculates the voltage at the "B+" terminal / 5 = V(1-5) single cell voltage through internal calculation.

[0122] In some implementations, such as Figure 2 As shown, the first voltage detection circuit 500 also includes a second switching diode D501, wherein the anode of the second switching diode D501 is connected to the other end of the fourteenth resistor R503.

[0123] One cathode of the second switching diode D501 is connected to the 3.3V power supply terminal.

[0124] The other cathode of the second switching diode D501 is connected to the common terminal.

[0125] In some implementations, such as Figure 2 As shown, in order to improve the reliability of the charging current switching, a first MOSFET Q201 and a second MOSFET Q202 connected in series can be set in the charging main circuit 200. The above MOSFETs are selected as P-channel enhancement-mode MOSFETs, and both have the function of switching.

[0126] Specifically, the drain of the first MOSFET Q201 is connected to the output terminal of the preceding charging module, and is used to receive or turn off the charging current input from the preceding stage.

[0127] The drain of the second MOSFET Q202 is connected to one input terminal (corresponding to the B+ terminal) of the battery terminal connector 400 to receive the charging current output by the second MOSFET Q202 for charging the battery pack.

[0128] The source of the first MOSFET Q201 and the source of the second MOSFET Q202 are connected.

[0129] In this configuration, a second Zener diode ZD202 and a second resistor R201 are connected in parallel between the source of the first MOSFET Q201 and the source of the second MOSFET Q202.

[0130] The gate of the first MOSFET Q201 and the gate of the second MOSFET Q202 are connected.

[0131] In some implementations, such as Figure 2 As shown, in order to improve the reliability of the charging current switching, a third MOSFET Q203 and a fourth MOSFET Q204 can be set in the charging main circuit 200. The above MOSFETs are selected as N-channel enhancement-type MOSFETs, and they all have the function of switching.

[0132] Specifically, the gate of the third MOSFET Q203 is connected to a signal output terminal (corresponding to pin 12) of the main controller U301 through the fourth resistor R204, for receiving the first control signal.

[0133] The drain of the third MOSFET Q203 is connected to the gates of the first MOSFET Q201 and the second MOSFET Q202 through the third resistor R202.

[0134] The source of the third MOSFET Q203 is connected to the drain of the fourth MOSFET Q204.

[0135] The gate of the fourth MOSFET Q204 is connected to a signal output terminal (pin 15) of the main controller U301 via the seventh resistor R206, and is used to receive the third control signal.

[0136] The source of the fourth MOSFET Q204 is connected to the common terminal.

[0137] When both the first and third control signals are high, the third MOSFET Q203 and the fourth MOSFET Q204 are turned on, pulling down the gate levels of the first MOSFET Q201 and the second MOSFET Q202 to control the first MOSFET Q201 and the second MOSFET Q202 to turn on, thereby outputting charging current to the subsequent circuit.

[0138] In some implementations, such as Figure 1 As shown, the LDO circuit 100 includes a power supply chip U100.

[0139] The input terminal (corresponding to the I terminal) of the power chip U100 is connected to the power supply terminal (V+) through the first resistor R101, and the output terminal (corresponding to the O terminal) of the power chip U100 outputs a voltage of +3.3V through the filter capacitor.

[0140] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A battery pack imbalance detection circuit, characterized in that, have: The main charging circuit is configured within the imbalance detection circuit to receive or shut off the charging current input from the previous stage. The main control circuit receives voltage signals at its power input terminal and outputs at least three control signals. The main control circuit has at least two preset values. A signal output terminal of the main control circuit is connected to a signal input terminal of the charging main circuit circuit, and is used to output a first control signal. A battery terminal connector, one of its input terminals being connected to the output terminal of the main charging circuit, is used to receive the charging current to charge the battery pack. The first voltage detection circuit has its first input terminal connected to the output terminal of the charging main circuit, and is used to acquire the charging current, convert and divide the charging current to output a first voltage signal. The second input terminal of the first voltage detection circuit is coupled to another signal output terminal of the main control circuit, and is used to receive the second control signal. The signal output terminal of the first voltage detection circuit is connected to a signal input terminal of the main control circuit, which is used to receive the first voltage signal after voltage division processing. The main control circuit analyzes the individual cell voltage of the battery pack based on the input first voltage signal; The second voltage detection circuit has one input terminal connected to a signal terminal of the battery terminal connector, used to acquire the charging current, and to convert and divide the charging current to output a second voltage signal. The output terminal of the second voltage detection circuit is connected to another signal input terminal of the main control circuit to receive the second voltage signal after voltage division. The main control circuit compares the second voltage signal with the preset value. When the second voltage signal is greater than the preset value, it determines that the voltage of the battery pack is unbalanced based on the comparison result.

2. The battery pack imbalance detection circuit according to claim 1, characterized in that, The second voltage detection circuit includes at least a sixth MOSFET, a seventeenth resistor, and an eighteenth resistor. The gate of the sixth MOS transistor is connected to an output terminal of the main control circuit through the nineteenth resistor. The drain of the sixth MOS transistor is connected to one end of the seventeenth resistor. The other end of the seventeenth resistor is connected to a signal terminal of the battery terminal connector to obtain the charging current. The source of the sixth MOS transistor is connected to one end of the eighteenth resistor. The other end of the eighteenth resistor is connected to another signal input terminal of the main control circuit.

3. The battery pack imbalance detection circuit according to claim 2, characterized in that, The second voltage detection circuit also includes a third switching diode. The anode of the third switching diode is connected to the other end of the eighteenth resistor. One cathode of the third switching diode is connected to a 5V power supply terminal. The other cathode of the third switching diode is connected to the common terminal.

4. The battery pack imbalance detection circuit according to claim 2, characterized in that, The main control circuit includes at least a main controller. The main controller's power input terminal is used to receive voltage signals, and it outputs at least three control signals. One signal output terminal of the main controller is connected to one signal input terminal of the charging main circuit, and is used to output the first control signal. Another signal output terminal of the main controller is connected to the second input terminal of the first voltage detection circuit, and is used to output the second control signal. One signal input terminal of the main controller is connected to the signal output terminal of the first voltage detection circuit, and is used to receive the first voltage signal after voltage division processing. The main controller analyzes the individual cell voltage of the battery pack based on the input first voltage signal; Another signal input terminal of the main controller is connected to one end of the eighteenth resistor, and is used to receive the second voltage signal after voltage division. The main controller compares the second voltage signal with the preset value. When the second voltage signal is greater than the preset value, it determines that the voltage of the battery pack is unbalanced based on the comparison result.

5. The battery pack imbalance detection circuit according to claim 4, characterized in that, The first voltage detection circuit includes at least a fifth MOSFET, a twelfth resistor, a thirteenth resistor, and a fourteenth resistor. One end of the twelfth resistor is connected to the output terminal of the main charging circuit to acquire the charging current and perform conversion and voltage division on the charging current to output the first voltage signal. The other end of the twelfth resistor is coupled to the drain of the fifth MOS transistor. The gate of the fifth MOS transistor is connected to one end of the thirteenth resistor. The other end of the thirteenth resistor is coupled to another signal output terminal of the main controller, and the second control signal is input to the gate of the fifth MOS transistor via the thirteenth resistor. The source of the fifth MOS transistor is connected to one end of the fourteenth resistor. The other end of the fourteenth resistor is connected to a signal input terminal of the main controller, and the first voltage signal is input to the main controller through the fourteenth resistor.

6. The battery pack imbalance detection circuit according to claim 5, characterized in that, The first voltage detection circuit also includes a second switching diode. The anode of the second switching diode is connected to the other end of the fourteenth resistor. One cathode of the second switching diode is connected to the 3.3V power supply terminal. The other cathode of the second switching diode is connected to the common terminal.

7. The battery pack imbalance detection circuit according to claim 5, characterized in that, The charging main circuit includes at least a first MOSFET and a second MOSFET connected in series. The drain of the first MOSFET is used to receive or turn off the charging current input from the previous stage. The drain of the second MOSFET is connected to an input terminal of the battery terminal connector to output the charging current for charging the battery pack. The source of the first MOSFET and the source of the second MOSFET are connected. The gates of the first MOSFET and the second MOSFET are connected.

8. The battery pack imbalance detection circuit according to claim 7, characterized in that, The charging main circuit 200 also includes a third MOSFET and a fourth MOSFET. The gate of the third MOS transistor is connected to a signal output terminal of the main controller through a fourth resistor. The drain of the third MOS transistor is connected to the gates of the first MOS transistor and the second MOS transistor respectively through a third resistor. The source of the third MOS transistor is connected to the drain of the fourth MOS transistor. The gate of the fourth MOS transistor is connected to a signal output terminal of the main controller through a seventh resistor. The source of the fourth MOS transistor is connected to the common terminal.

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