BMS heating protection circuit and fault detection method

Abstract

The invention relates to the technical field of batteries, and discloses a BMS heating protection circuit and a fault detection method.The protection circuit comprises a switch control circuit, a heating connector, a heating power source, an anti-reverse-connection circuit and a secondary protection circuit, one end of the heating connector is connected with one end of the anti-reverse-connection circuit, and the other end of the heating connector is connected with the other end of the anti-reverse-connection circuit; the other end of the heating connector is connected with the negative electrode of the heating power supply through a heating switch of the switch control circuit; and the positive electrode of the heating power supply is also connected with the secondary protection circuit, and the secondary protection circuit is used for performing fusing protection when the heating switch is short-circuited or cannot be switched off. By adopting the heating protection circuit, the problems that the battery cell is continuously heated due to improper installation and reverse power polarity connection when the PACK is installed, and the battery cell is continuously heated to cause thermal runaway when the heating switch cannot be switched off due to short-circuit fault of the heating switch MOS driving loop or the MOS itself in the heating loop are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a BMS heating protection circuit and fault detection method. Background Technology

[0002] The replacement of lead-acid batteries with lithium batteries as backup power for communication base stations is becoming a major trend. Compared to lead-acid batteries, lithium batteries have significant advantages such as higher energy density, higher charge / discharge rates, and the ability to operate at relatively high temperatures. However, at low temperatures, the charge / discharge performance of lithium batteries drops sharply. To address this issue, a common approach is to design a heating function. This involves equipping the PACK (battery pack) module with a heating film, and the BMS (Battery Management System) designing a heating film control circuit. Based on the cell temperature detected by the BMS and the heating-on / off strategy, the PACK cell module is heated at low temperatures to ensure normal operation. However, existing heating film control circuits have limitations under certain extreme conditions that can cause the heating film control loop to fail. When the heating film is always on, the cell module will be continuously heated, potentially leading to thermal runaway. Alternatively, if the battery module is reverse-connected to the power supply, the drive circuit cannot be effectively disconnected, and the heating film continues to heat the cell module through the reversed power supply, also potentially causing thermal runaway. Summary of the Invention

[0003] To address the above problems, this invention provides a BMS heating protection circuit and fault detection method, which effectively solves the problem of thermal runaway caused by continuous heating due to faults.

[0004] The purpose of this invention is to provide a BMS heating protection circuit, including a switch control circuit, a heating connector, a heating power supply, a reverse connection protection circuit, and a secondary protection circuit, wherein... One end of the heating connector is connected to one end of the reverse connection protection circuit, the other end of the reverse connection protection circuit is connected to the positive terminal of the heating power supply, and the other end of the heating connector is connected to the negative terminal of the heating power supply through the heating switch of the switch control circuit. The positive terminal of the heating power supply is also connected to a secondary protection circuit, which is used to provide fuse protection when the heating switch is short-circuited or cannot be disconnected.

[0005] Furthermore, the reverse connection protection circuit includes diodes D2 and D3, which are connected in parallel. The negative terminals of diodes D2 and D3 are both connected to the second input terminal of the heating connector, and the positive terminals of diodes D2 and D3 are both connected to the positive terminal of the heating power supply.

[0006] Furthermore, the secondary protection circuit includes a three-terminal fuse F20, diode D5, MOSFET Q5, transistor Q6, transistor Q7, resistors R8, R9, R10, R11, R12, and R13, among which... One end of the three-terminal fuse F20 is connected to the positive terminal of the heating power supply. The other end of the three-terminal fuse F20 is connected to the positive terminal of diode D5. The negative terminal of diode D5 is connected to the drain of MOSFET Q5. The gate of MOSFET Q5 is connected to one end of resistor R10 and one end of resistor R11. The other end of R10 is connected to the collector of transistor Q6. The other end of resistor R11 is grounded to both the source and the source of MOSFET Q5. The base of transistor Q6 is connected to one end of resistor R8 and one end of resistor R9. The other end of resistor R8 and the emitter of transistor Q6 are both connected to the DC power supply input terminal. The other end of resistor R9 is connected to the collector of transistor Q7. The base of transistor Q7 is connected to one end of resistor R12 and one end of resistor R13. The emitter of transistor Q7 and the other end of resistor R12 are both grounded. The other end of resistor R13 is connected to the input terminal of the fuse blowout control signal.

[0007] Furthermore, when the fuse control signal input to the fuse blowing control signal input terminal is at a low level, the three-terminal fuse F20 conducts normally; When the fuse control signal input terminal is set to a high level, the three-terminal fuse F20 will be controlled to blow actively.

[0008] Furthermore, the secondary protection circuit includes a resistor R30, a photoelectric MOSFET U11, and a fuse F1. The first end of the photoelectric MOSFET U11 is connected to the power supply, and the first end of the photoelectric MOSFET U11 is connected to the input terminal of the fuse blowout control signal through the resistor R30. The third and fourth ends of the photoelectric MOSFET U11 are both connected to one end of the fuse F1, and the other end of the fuse F1 is connected to the positive terminal of the heating power supply.

[0009] Furthermore, the heating switch is a MOSFET Q2, and the switch control circuit also includes resistors R1, R2, Q3, R3, R4, Q1, R5, R6, R7, Zener diode ZD9, and TVS1. One end of resistor R1 is connected to the input terminal of the first control signal. The other end of resistor R1 is connected to one end of resistor R2 and the base of transistor Q3. The other end of R2 and the emitter of transistor Q3 are grounded. The collector of transistor Q3 is connected to one end of resistor R3. The other end of resistor R3 is connected to one end of resistor R4 and the base of transistor Q1. The other end of resistor R4 is connected to the positive terminal of the heating power supply and the emitter of transistor Q1. The collector of transistor Q1 is connected to one end of resistor R5. The other end is connected to one end of resistor R6. The other end of resistor R6 is connected to one end of resistor R7, the gate of MOSFET Q2, and one end of Zener diode ZD9. The other end of resistor R7, the source of MOSFET Q2, and the other end of Zener diode ZD9 are all connected to the negative terminal of the heating power supply. The drain of MOSFET Q2 is connected to one end of the heating connector. The other end of the heating connector is also connected to the output terminal of the HT_D signal. The two ends of diode TVS1 are connected to the drain and source of MOSFET Q2, respectively.

[0010] Furthermore, it also includes a fault detection circuit for detecting the output state of the first control signal and the input level of the fault detection circuit output signal HT_AD, wherein, The fault detection circuit includes resistors R282, R283, and R285, capacitor C85, and bidirectional diode D56. One end of resistor R282 is connected to the output terminal of the HT_D signal, and the other end of resistor R282 is connected to one end of resistor R283 and one end of resistor R285. The other end of resistor R283 is grounded. The other end of resistor R285 is connected to the output terminal of bidirectional diode D56 and the output terminal of the fault detection circuit. The first input terminal of bidirectional diode D56 is grounded, and the second input terminal is connected to the power supply. One end of capacitor C85 is connected to the output terminal of bidirectional diode D56, and the other end of capacitor C85 is grounded.

[0011] Furthermore, it also includes a BMS management module, which is connected to the fault detection circuit, the switch control circuit, the heating connector, and the secondary protection circuit.

[0012] Another object of the present invention is to provide a fault detection method for the BMS heating protection circuit described above, comprising: Real-time detection of the output status of the first control signal HT_DR and the input level of the fault detection circuit output signal HT_AD; The system determines whether the output state of the first control signal HT_DR and the input level of the fault detection circuit output signal HT_AD are both low. If the output state of HT_DR is low and the input level of HT_AD is low for more than a first preset time, it determines whether the temperature of the battery cell is higher than a preset temperature. If the temperature of any cell exceeds the preset temperature, the heating circuit is deemed to have failed, and the three-terminal fuse F20 is automatically blown.

[0013] Furthermore, the preset temperature is the discharge over-temperature protection value of -5℃.

[0014] The present invention employs the above-mentioned heating protection circuit to effectively solve the problems of continuous heating of the battery cell due to improper installation or reversed power polarity during PACK installation, and the problem of continuous heating of the battery cell leading to thermal runaway when the heating switch cannot be turned off due to a short circuit fault in the heating switch MOS drive circuit or the MOS itself.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of a BMS heating protection circuit structure is shown in an embodiment of the present invention; Figure 2 A schematic diagram of another BMS heating protection circuit structure is shown in an embodiment of the present invention; Figure 3 A schematic diagram of a fault detection circuit structure for a BMS heating protection circuit according to an embodiment of the present invention is shown. Figure 4 This invention illustrates a schematic diagram of the secondary protection circuit in a BMS heating protection circuit according to an embodiment of the present invention. Figure 5 A schematic flowchart of a fault detection method for a BMS heating protection circuit according to an embodiment of the present invention is shown. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1 As shown in the illustration, this invention introduces a BMS heating protection circuit. The heating protection circuit includes a switch control circuit, a heating connector, a heating power supply, a reverse connection protection circuit, and a secondary protection circuit. One end of the heating connector is connected to one end of the reverse connection protection circuit, and the other end of the reverse connection protection circuit is connected to the positive terminal of the heating power supply. The other end of the heating connector is connected to the negative terminal of the heating power supply through a heating switch in the switch control circuit. The positive terminal of the heating power supply is also connected to the secondary protection circuit, which provides fuse protection when the heating switch is short-circuited or cannot be disconnected. This heating protection circuit effectively solves the problems of continuous heating of the battery cells due to improper installation and reversed power polarity during PACK installation, and thermal runaway caused by continuous heating of the battery cells due to short circuit faults in the heating switch's drive circuit or the heating switch itself, preventing the heating switch from being disconnected.

[0020] like Figure 2 As shown, the reverse connection protection circuit includes diodes D2 and D3 connected in parallel. The negative terminals of both diodes D2 and D3 are connected to the second input terminal of the heating connector CON1, and the positive terminals are connected to the positive terminals B+ / P+ of the heating power supply. The heating connector CON1 is ultimately connected to the heating film. When the battery needs heating, the BMS (Battery Management System) module controls the heating switch Q2 (NMOS) to turn on via the first control signal HT_DR (hereinafter referred to as HT_DR). The power supply voltage at both ends B+ / P+ and P- can then be supplied to CON1 through Q2 to power the heating film. When heating stops, the BMS controls the heating switch or Q2 (NMOS) to turn off via HT_DR. In the event of a reverse connection, the heating circuit output by the power supply, through the body diode of the original heating switch MOS transistor Q2, is blocked by the diodes D2 and D3 in the added reverse connection protection circuit, thus solving the problem of continuous power supply to the heating film to heat the battery cell in reverse connection. Furthermore, the reverse connection protection circuit is not limited to this. The reverse connection protection circuit can also be a PMOS transistor, which is connected between the heating connector CON1 and the positive terminal of the heating power supply.

[0021] In embodiments of the present invention, such as Figure 2 As shown, the secondary protection circuit includes a three-terminal fuse F20, diode D5, MOSFET Q5, transistor Q6, transistor Q7, resistors R8, R9, R10, R11, R12, and R13. One end of the three-terminal fuse F20 is connected to the positive terminal B+ / P+ of the heating power supply, and the other end is connected to the anode of diode D5. The cathode of diode D5 is connected to the drain of MOSFET Q5. The gate of MOSFET Q5 is connected to one end of resistor R10 and one end of resistor R11, respectively. The other end of R10 is connected to transistor Q6. The collector of transistor Q5 is connected to the ground, and the other end of resistor R11 is grounded to the source of MOSFET Q5. The base of transistor Q6 is connected to one end of resistor R8 and one end of resistor R9, and the other end of resistor R8 and the emitter of transistor Q6 are both connected to the DC power supply input. The other end of resistor R9 is connected to the collector of transistor Q7, and the base of transistor Q7 is connected to one end of resistor R12 and one end of resistor R13, and the emitter of transistor Q7 and the other end of resistor R12 are both grounded. The other end of resistor R13 is connected to the input of the fuse blowing control signal HEAT_FUSE. Furthermore, the DC power supply is a 13V DC power supply used to power the secondary protection circuit. Under normal circumstances, the HEAT_FUSE control signal for the three-terminal fuse F20 is low, and the fuse F20 conducts normally. When the BMS management module detects a short circuit fault in the heating switch MOSFET Q2 or a failure in the MOSFET Q2 drive circuit that prevents MOSFET-Q2 from disconnecting, the BMS management module controls HEAT_FUSE to go high, thus controlling the three-terminal fuse F20 to automatically blow. This solves the problem of the power supply continuously supplying power to the heating film and heating the battery cell when the heating switch MOSFET is short-circuited or cannot be disconnected. More preferably, the three-terminal fuse can also be replaced by a relay, optocoupler power MOSFET, or other MOSFET switches.

[0022] In this embodiment of the invention, the secondary protection circuit is not limited to the circuit described above, such as... Figure 4 As shown, the secondary protection circuit can also include a resistor R30, a photoelectric MOSFET U11, and a fuse F1. The first terminal of the photoelectric MOSFET U11 is connected to the power supply, and the first terminal of the photoelectric MOSFET U11 is connected to the input terminal of the fuse blowing control signal through the resistor R30. The third and fourth terminals of the photoelectric MOSFET U11 are both connected to one end of the fuse F1, and the other end of the fuse F1 is connected to the positive terminal of the heating power supply. Similarly, when the BMS management module detects a short circuit fault in the heating switch MOSFET Q2 or when MOSFET Q2 cannot be disconnected due to a fault in the MOSFET Q2 drive circuit, the BMS management module controls HEAT_FUSE to go high, thus controlling the three-terminal fuse F1 to blow actively.

[0023] In embodiments of the present invention, such as Figure 2As shown, the heating switch is MOSFET Q2. The switch control circuit also includes resistors R1 and R2, transistors Q3, R4, R5, R6, and R7, a Zener diode ZD9, and a TVS1 diode. TVS1 is a protection device for MOSFET Q2. Furthermore, resistors R1 and R2, transistors Q3, R4, Q1, R5, R6, and R7, Zener diode ZD9, and TVS1 together form the switch drive circuit. One end of resistor R1 is connected to the input terminal of the first control signal HT_DR. The other end of resistor R1 is connected to one end of resistor R2 and the base of transistor Q3. The other end of R2 and the emitter of transistor Q3 are grounded. The collector of transistor Q3 is connected to one end of resistor R3. The other end of resistor R3 is connected to one end of resistor R4 and the base of transistor Q1. The other end of resistor R4 is connected to... The positive terminal of the heating power supply is connected to the emitter of transistor Q1; the collector of transistor Q1 is connected to one end of resistor R5, the other end of resistor R5 is connected to one end of resistor R6, the other end of resistor R6 is connected to one end of resistor R7, the gate of MOSFET Q2, and one end of Zener diode ZD9, the other end of resistor R7, the source of MOSFET Q2, and the other end of Zener diode ZD9 are all connected to the negative terminal P- of the heating power supply; the drain of MOSFET Q2 is connected to one end of the heating connector, the other end of the heating connector is also connected to the output terminal of the HT_D signal, and the two ends of diode TVS1 are connected to the drain and source of MOSFET Q2, respectively.

[0024] In embodiments of the present invention, such as Figure 3 As shown, the BMS heating protection circuit also includes a fault detection circuit for detecting the output status of the first control signal HT_DR and the input level of the fault detection circuit output signal HT_AD. The fault detection circuit includes resistors R282, R283, and R285, capacitor C85, and bidirectional diode D56. One end of resistor R282 is connected to the HT_D signal output terminal (i.e., the HT_D signal output terminal is the fault detection point, which is connected to the source of the MOS, and the HT_D signal detects the drain voltage of the MOS). The other end of resistor R282 is connected to one end of resistor R283 and one end of resistor R285, respectively. The other end of resistor R283 is grounded. The other end of resistor R285 is connected to the output terminal of bidirectional diode D56 and the output terminal of the fault detection circuit, respectively. The first input terminal of bidirectional diode D56 is grounded, and the second input terminal is connected to the power supply. One end of capacitor C85 is connected to the output terminal of bidirectional diode D56, and the other end of capacitor C85 is grounded. Furthermore, the bidirectional diode D56 prevents the input voltage from exceeding the withstand voltage of the signal receiving port, thus achieving voltage protection.

[0025] In this embodiment of the invention, Figure 2 and Figure 3 The circuit is connected via the HT_D signal output terminal, which is further connected to the BMS management module and processed by the microcontroller in the BMS management module. The HT_D signal detects the drain voltage of the MOS. When the MOS experiences a short circuit, the MOS driver cannot control the MOS to turn on or off. Therefore, the VDS (voltage difference between the drain (D) and source (S)) voltage of the MOS remains low. In this case, the detection is in failure mode. The fault detection circuit determines whether there is a short circuit fault in MOS transistor Q2. After identifying the fault signal, it activates the secondary protection circuit where the fuse is located, causing the fuse to blow and breaking the circuit. Thus, the fault detection circuit and the secondary protection circuit work together to ensure the safety and reliability of the BMS heating protection circuit.

[0026] In this embodiment of the invention, the BMS heating protection circuit further includes a BMS management module. The BMS management module is connected to the fault detection circuit, the switch control circuit, the heating connector, and the secondary protection circuit, respectively, and is used to output corresponding signals or detect corresponding input signals to control the BMS heating protection circuit. Furthermore, the BMS management module includes a microcontroller, which controls both the output and input signals in the above circuit.

[0027] like Figure 5 As shown in the figure, this embodiment of the invention also introduces a fault detection method for the BMS heating protection circuit described above, the method comprising, First, the BMS monitors the output status of the first control signal HT_DR and the input level of the fault detection circuit output signal HT_AD in real time; the fault detection circuit inputs the HT_AD signal to the microcontroller of the BMS management module for identification.

[0028] Then, the output state of the first control signal HT_DR and the input level of the fault detection circuit output signal HT_AD are determined. If the output state of HT_DR is low and the input level of HT_AD is low for more than a first preset time, it is determined whether the temperature of any cell is higher than the preset temperature. If the temperature of any cell is higher than the preset temperature, the heating circuit is determined to be faulty, and the three-terminal fuse F20 is actively blown. Further, the first preset time is 10 seconds, but it is not limited to this; 15 seconds, 20 seconds, etc., are also applicable to this invention. The preset temperature is the discharge over-temperature protection value -5℃. For example, the discharge over-temperature protection value can be 65℃, thus the preset temperature is 60℃, but it is not limited to this; the discharge over-temperature protection value can also be 63℃, etc.

[0029] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A BMS heating protection circuit, characterized in that, It includes a switch control circuit, a heating connector, a heating power supply, a reverse connection protection circuit, and a secondary protection circuit. One end of the heating connector is connected to one end of the reverse connection protection circuit, the other end of the reverse connection protection circuit is connected to the positive terminal of the heating power supply, and the other end of the heating connector is connected to the negative terminal of the heating power supply through the heating switch of the switch control circuit. The positive terminal of the heating power supply is also connected to a secondary protection circuit, which is used to provide fuse protection when the heating switch is short-circuited or cannot be disconnected.

2. The BMS heating protection circuit according to claim 1, characterized in that, The reverse connection protection circuit includes diodes D2 and D3, which are connected in parallel. The negative terminals of diodes D2 and D3 are both connected to the second input terminal of the heating connector, and the positive terminals of diodes D2 and D3 are both connected to the positive terminal of the heating power supply.

3. The BMS heating protection circuit according to claim 2, characterized in that, The secondary protection circuit includes a three-terminal fuse F20, diode D5, MOSFET Q5, transistor Q6, transistor Q7, resistors R8, R9, R10, R11, R12, and R13. One end of the three-terminal fuse F20 is connected to the positive terminal of the heating power supply. The other end of the three-terminal fuse F20 is connected to the positive terminal of diode D5. The negative terminal of diode D5 is connected to the drain of MOSFET Q5. The gate of MOSFET Q5 is connected to one end of resistor R10 and one end of resistor R11. The other end of R10 is connected to the collector of transistor Q6. The other end of resistor R11 is grounded to both the source and the source of MOSFET Q5. The base of transistor Q6 is connected to one end of resistor R8 and one end of resistor R9. The other end of resistor R8 and the emitter of transistor Q6 are both connected to the DC power supply input terminal. The other end of resistor R9 is connected to the collector of transistor Q7. The base of transistor Q7 is connected to one end of resistor R12 and one end of resistor R13. The emitter of transistor Q7 and the other end of resistor R12 are both grounded. The other end of resistor R13 is connected to the input terminal of the fuse blowout control signal.

4. The BMS heating protection circuit according to claim 3, characterized in that, When the fuse control signal input to the fuse blowing control signal input terminal is at a low level, the three-terminal fuse F20 will conduct normally; When the fuse control signal input terminal is set to a high level, the three-terminal fuse F20 will be controlled to blow actively.

5. The BMS heating protection circuit according to claim 2, characterized in that, The secondary protection circuit includes a resistor R30, a photoelectric MOSFET U11, and a fuse F1. The first end of the photoelectric MOSFET U11 is connected to the power supply, and the first end of the photoelectric MOSFET U11 is connected to the input terminal of the fuse blowout control signal through the resistor R30. The third and fourth ends of the photoelectric MOSFET U11 are both connected to one end of the fuse F1, and the other end of the fuse F1 is connected to the positive terminal of the heating power supply.

6. The BMS heating protection circuit according to claim 3 or 5, characterized in that, The heating switch is a MOSFET Q2. The switch control circuit also includes resistors R1 and R2, transistors Q3, R4, R5, R6, and R7, a Zener diode ZD9, and a TVS1 diode. One end of resistor R1 is connected to the input terminal of the first control signal. The other end of resistor R1 is connected to one end of resistor R2 and the base of transistor Q3. The other end of R2 and the emitter of transistor Q3 are grounded. The collector of transistor Q3 is connected to one end of resistor R3. The other end of resistor R3 is connected to one end of resistor R4 and the base of transistor Q1. The other end of resistor R4 is connected to the positive terminal of the heating power supply and the emitter of transistor Q1. The collector of transistor Q1 is connected to one end of resistor R5. The other end is connected to one end of resistor R6. The other end of resistor R6 is connected to one end of resistor R7, the gate of MOSFET Q2, and one end of Zener diode ZD9. The other end of resistor R7, the source of MOSFET Q2, and the other end of Zener diode ZD9 are all connected to the negative terminal of the heating power supply. The drain of MOSFET Q2 is connected to one end of the heating connector. The other end of the heating connector is also connected to the output terminal of the HT_D signal. The two ends of diode TVS1 are connected to the drain and source of MOSFET Q2, respectively.

7. The BMS heating protection circuit according to claim 6, characterized in that, It also includes a fault detection circuit for detecting the output state of the first control signal and the input level of the fault detection circuit output signal HT_AD, wherein, The fault detection circuit includes resistors R282, R283, and R285, capacitor C85, and bidirectional diode D56. One end of resistor R282 is connected to the output terminal of the HT_D signal, and the other end of resistor R282 is connected to one end of resistor R283 and one end of resistor R285. The other end of resistor R283 is grounded. The other end of resistor R285 is connected to the output terminal of bidirectional diode D56 and the output terminal of the fault detection circuit. The first input terminal of bidirectional diode D56 is grounded, and the second input terminal is connected to the power supply. One end of capacitor C85 is connected to the output terminal of bidirectional diode D56, and the other end of capacitor C85 is grounded.

8. The BMS heating protection circuit according to claim 7, characterized in that, It also includes a BMS management module, which is connected to the fault detection circuit, the switch control circuit, the heating connector, and the secondary protection circuit.

9. A fault detection method for a BMS heating protection circuit according to any one of claims 1-8, characterized in that, include, Real-time detection of the output status of the first control signal HT_DR and the input level of the fault detection circuit output signal HT_AD; The system determines whether the output state of the first control signal HT_DR and the input level of the fault detection circuit output signal HT_AD are both low. If the output state of HT_DR is low and the input level of HT_AD is low for more than a first preset time, it determines whether the temperature of the battery cell is higher than a preset temperature. If the temperature of any cell exceeds the preset temperature, the heating circuit is deemed to have failed, and the three-terminal fuse F20 is automatically blown.

10. The fault detection method for the BMS heating protection circuit according to claim 9, characterized in that, The preset temperature is the discharge over-temperature protection value of -5℃.

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