A battery management system for a vehicle

Abstract

The utility model provides a kind of battery management system for vehicle, vehicle includes whole vehicle controller, comprising: high voltage unit, including high voltage acquisition chip circuit and analog front end module, high voltage acquisition chip circuit is used to collect the first detection information of battery pack when vehicle is in non low power mode, analog front end module is used to collect the second detection information of battery pack when vehicle is in non low power mode and low power mode;Low voltage unit, including communication conversion chip circuit and communication circuit, communication conversion chip circuit is used to receive the first detection information and second detection information transmitted to it by daisy chain, and the first detection information and second detection information are transmitted to whole vehicle controller by communication circuit.The battery management system of the utility model is simple in structure, low in cost, strong in adaptability, and does not need additional MCU.

Description

Technical Field

[0001] This utility model belongs to the field of battery management systems, and specifically relates to a battery management system for vehicles. Background Technology

[0002] With the rapid development of new energy vehicles, the Battery Management System (BMS), as one of the core components of electric vehicles, is crucial to the safe operation of the entire vehicle due to its performance and reliability. The BMS is primarily responsible for monitoring parameters such as voltage, current, and temperature of the battery pack, assessing the battery status, and taking protective measures when necessary to ensure the safe operation of the battery pack.

[0003] Currently, battery management systems for electric vehicles mainly employ two design approaches: master-slave architecture and integrated architecture. The master-slave architecture typically includes one master controller and multiple slave controllers. The master controller is responsible for overall control and communication with the vehicle, while the slave controllers are responsible for collecting data from individual battery cells. The integrated architecture, on the other hand, integrates all functions into a single control unit.

[0004] Patent document CN119906075A discloses a battery management system. The battery management system adopts a master-slave architecture, in which a first master controller controls the energy storage system and / or a first slave controller. An additional microcontroller unit (MCU) is required to control the slave controller.

[0005] Regardless of whether it is a master-slave architecture or an integrated architecture, the existing BMS requires a separate MCU chip to support the design, resulting in high hardware costs and a serious waste of MCU resources. Secondly, due to the need for an additional MCU chip, the existing architecture also requires additional software development, which is time-consuming and costly.

[0006] Therefore, there is an urgent need for a battery management system that is simple in structure, low in cost, highly adaptable, and does not require an additional MCU to meet the requirements for safe and reliable operation of electric vehicles. Utility Model Content

[0007] The purpose of this invention is to solve the problem of how to provide a battery management system that is simple in structure, low in cost, highly adaptable, and does not require an additional MCU.

[0008] In a first aspect, this utility model provides a battery management system for a vehicle, the vehicle including a vehicle controller, comprising:

[0009] The high-voltage unit includes a high-voltage acquisition chip circuit and an analog front-end module. The high-voltage acquisition chip circuit is used to acquire first detection information of the battery pack when the vehicle is in a non-low-power mode. The analog front-end module is used to acquire second detection information of the battery pack when the vehicle is in a low-power mode. The first detection information includes one or more of voltage, current, relay status and insulation status. The second detection information includes voltage and / or temperature.

[0010] The low-voltage unit includes a communication conversion chip circuit and a communication circuit. The communication conversion chip circuit is used to receive first detection information and second detection information transmitted to it through a daisy chain, and to transmit the first detection information and second detection information to the vehicle controller through the communication circuit.

[0011] Using the above technical solution, the high-voltage acquisition chip circuit can acquire one or more of the following: voltage, current, relay status, and insulation status of the battery pack when the vehicle is in non-low power mode. The analog front-end module can acquire the voltage and / or temperature of the battery pack when the vehicle is in both non-low power and low power modes. The communication conversion chip circuit is used to receive the first and second detection information transmitted to it through a daisy chain, and transmit the first and second detection information to the vehicle controller through the communication circuit. The battery management system transfers the mode decision-making function traditionally undertaken by the MCU to the vehicle's existing vehicle controller, thereby achieving a simple, low-cost, and highly adaptable battery management system that does not require an additional MCU.

[0012] According to another specific embodiment of the present invention, the vehicle controller is used to respond to the first detection information to determine the SOC of the battery pack and / or to determine whether a thermal runaway fault has occurred.

[0013] According to another specific embodiment of this utility model, the low-voltage unit further includes: a reverse wake-up circuit.

[0014] The output of the communication conversion chip circuit is connected to the input of the reverse wake-up circuit, and the output of the reverse wake-up circuit is connected to the input of the vehicle controller.

[0015] When the simulation front-end module detects that the second detection information exceeds the preset thermal runaway threshold, the simulation front-end module outputs the first output signal to the communication conversion chip circuit, the communication conversion chip circuit outputs the first control signal to the reverse wake-up circuit, and the reverse wake-up circuit outputs the second control signal to wake up the vehicle controller, so that the vehicle switches from low power mode to non-low power mode.

[0016] According to another specific embodiment of the present invention, the battery management system includes a storage battery, and the low-voltage unit further includes a filter protection and anti-reverse circuit, which includes:

[0017] The voltage output terminal is used to output a second voltage, which is the filtered voltage.

[0018] The filtering module includes a first capacitor bank, a first inductor, and a second capacitor bank. One end of the first inductor is connected to the anode of the first capacitor bank, and the other end of the first inductor is connected to the anode of the second capacitor bank. The anode of the second capacitor bank is connected to the voltage output terminal, and the cathode of the second capacitor bank is connected to the ground terminal.

[0019] The anti-reverse module has its anode connected to the positive terminal of the battery and its cathode connected to the anode of the first capacitor bank of the filter module. This is used to prevent the battery from being connected in reverse and damaging the components in the circuit.

[0020] A surge absorption module is configured to absorb surge signals. The anode of the surge absorption module is connected to the cathode of the anti-reverse module, and the cathode of the surge absorption module is connected to the negative terminal of the battery.

[0021] According to another specific embodiment of the present invention, the low-voltage unit includes a reverse wake-up circuit, which includes:

[0022] The base of the first transistor is connected to the output terminal of the communication conversion chip circuit, and the collector of the first transistor is connected to the ground terminal.

[0023] The base of the second transistor is connected to the emitter of the first transistor, and the emitter of the second transistor is connected to the voltage output terminal, which is used to provide a second voltage for the reverse wake-up circuit. The collector of the second transistor is connected to the vehicle controller.

[0024] When the communication conversion chip circuit receives the first output signal from the analog front-end module, the first control signal output by the communication conversion chip circuit is high level, the first transistor is turned on, the emitter of the first transistor is high level, the second transistor is turned on, and the collector of the second transistor outputs the second control signal to wake up the vehicle controller.

[0025] According to another specific embodiment of this utility model, the high-voltage unit further includes a relay diagnostic circuit, which is connected to the high-voltage acquisition chip circuit and is used to acquire the relay status of the battery pack. The relay diagnostic circuit includes:

[0026] Voltage input terminal;

[0027] The third voltage divider resistor has its first end connected to the voltage input terminal and its second end connected to the high voltage acquisition chip circuit.

[0028] The fourth voltage divider resistor has its first terminal connected to the second terminal of the third voltage divider resistor.

[0029] The relay has its first terminal connected to the second terminal of the fourth voltage divider resistor, and its second terminal connected to the negative terminal of the battery pack.

[0030] The fifth voltage divider resistor has its first end connected to the second end of the third voltage divider resistor, and its second end connected to the negative terminal of the battery pack.

[0031] By inputting voltage to the voltage input terminal, the system determines whether the relay is on or off based on the voltage value collected by the high-voltage acquisition chip circuit.

[0032] According to another specific embodiment of this utility model, the high-voltage unit further includes a current detection circuit, which is connected to the high-voltage acquisition chip circuit and is used to acquire the current of the battery pack. The current detection circuit includes:

[0033] The shunt sensor includes a first filter circuit, a second filter circuit, a third filter circuit, a fourth filter circuit, a first voltage divider resistor, a second voltage divider resistor, a first anti-reverse circuit, a second anti-reverse circuit, and a fifth filter circuit.

[0034] The fifth filter circuit includes a first capacitor and a second capacitor. The anode of the first capacitor is connected to the first terminal of the shunt meter type sensor, the anode of the second capacitor is connected to the second terminal of the shunt meter type sensor, and the cathodes of the first capacitor and the cathodes of the second capacitor are connected to the negative terminal of the battery pack.

[0035] In this circuit, the first end of the shunt meter sensor is connected to the high-voltage acquisition chip circuit via a first voltage divider resistor, the second end of the shunt meter sensor is connected to the high-voltage acquisition chip circuit via a second voltage divider resistor, the anode of the first filter circuit is connected to the first end of the shunt meter sensor, the cathode of the first filter circuit is connected to the negative terminal of the battery pack, the anode of the second filter circuit is connected to the second end of the shunt meter sensor, the cathode of the second filter circuit is connected to the negative terminal of the battery pack, the anode of the third filter circuit is connected to the first end of the first voltage divider resistor, the cathode of the third filter circuit is connected to the negative terminal of the battery pack, the anode of the fourth filter circuit is connected to the first end of the second voltage divider resistor, the cathode of the fourth filter circuit is connected to the negative terminal of the battery pack, the anode of the first anti-reverse circuit is connected to the first end of the shunt meter sensor, the cathode of the first anti-reverse circuit is connected to the negative terminal of the battery pack, the anode of the second anti-reverse circuit is connected to the second end of the shunt meter sensor, and the cathode of the second anti-reverse circuit is connected to the negative terminal of the battery pack.

[0036] The high-voltage acquisition chip circuit calculates the battery pack current based on the voltage across the shunt sensor.

[0037] According to another specific embodiment of the present invention, the communication conversion chip circuit includes an MC33665 chip, and / or the communication circuit includes CAN communication or CAN FD communication.

[0038] According to another specific embodiment of this utility model, the low-voltage unit further includes: a wake-up circuit, a power supply circuit, and an isolation power supply circuit.

[0039] When the reverse wake-up circuit outputs the second control signal to wake up the vehicle controller, the vehicle controller outputs the third control signal to activate the wake-up circuit, and the wake-up circuit outputs the fourth control signal to activate the power supply circuit and the isolation power supply circuit. The power supply circuit supplies power to the high-voltage acquisition chip circuit through the isolation power supply circuit.

[0040] The isolated power supply circuit includes:

[0041] The driver chip includes a first output port, a second output port, a power supply terminal, and a control port. The power supply terminal is used to provide the third voltage output by the power supply circuit.

[0042] The transformer is connected to the first output port and the second output port respectively. The transformer includes a first primary winding and a first secondary winding, as well as a second primary winding and a second secondary winding.

[0043] The third anti-reverse circuit and the fourth anti-reverse circuit are respectively configured to provide the induced voltage to the load terminal. The third anti-reverse circuit is connected to the first secondary winding, and the fourth anti-reverse circuit is connected to the second secondary winding.

[0044] The sixth filter circuit has its anode connected to the first output port and its cathode connected to the ground terminal.

[0045] The seventh filter circuit has its anode connected to the second output port and its cathode connected to the ground terminal.

[0046] The eighth filter circuit has its anode connected to the power supply terminal and its cathode connected to the ground terminal.

[0047] When the wake-up circuit outputs the fourth control signal, the control port of the driver chip is at a high level. The first output port and the second output port alternately output voltage signals to excite the corresponding primary winding, so that the corresponding secondary winding can generate an induced voltage.

[0048] According to another specific embodiment of the present invention, the battery management system further includes a relay drive circuit for controlling the on and off of the relay.

[0049] The communication conversion chip circuit includes a GPIO output port, which is connected to the relay driver circuit. When the GPIO output port is high, the relay driver circuit controls the relay to turn on; when the GPIO output port is low, the relay driver circuit controls the relay to turn off.

[0050] And / or,

[0051] The high-voltage unit also includes a voltage acquisition circuit for acquiring voltage information from the battery pack. The voltage acquisition circuit includes:

[0052] The sixth voltage divider resistor has its first terminal connected to the positive terminal of the battery pack.

[0053] The seventh voltage divider resistor has its first end connected to the second end of the sixth voltage divider resistor. The first end of the seventh voltage divider resistor is connected to the high voltage acquisition chip circuit, and the second end of the seventh voltage divider resistor is connected to the negative terminal of the battery pack.

[0054] The resistance of the sixth voltage divider resistor is greater than that of the seventh voltage divider resistor. Attached Figure Description

[0055] Figure 1 This diagram illustrates the architecture of a battery management system. Figure 1 ;

[0056] Figure 2 This illustrates an alternative battery management system architecture. Figure 2 ;

[0057] Figure 3 A schematic diagram of the architecture of the battery management system in an embodiment of this utility model is shown;

[0058] Figure 4 A circuit diagram of the filter protection and anti-reverse circuit in an embodiment of this utility model is shown;

[0059] Figure 5 The circuit diagram of the reverse wake-up circuit in an embodiment of this utility model is shown;

[0060] Figure 6 A circuit diagram of the relay diagnostic circuit in an embodiment of this utility model is shown;

[0061] Figure 7 A circuit diagram of the current detection circuit in an embodiment of this utility model is shown;

[0062] Figure 8 A circuit diagram of the isolated power supply circuit in an embodiment of this utility model is shown;

[0063] Figure 9 A circuit diagram of the voltage acquisition circuit in an embodiment of this utility model is shown;

[0064] Figure 10 A circuit diagram of the insulation detection circuit in an embodiment of this utility model is shown;

[0065] Figure 11 The diagram shows a schematic of the power supply circuit in an embodiment of this utility model. Detailed Implementation

[0066] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Although the description of this utility model will be presented in conjunction with preferred embodiments, this does not mean that the features of this utility model are limited to this embodiment. On the contrary, the purpose of describing the utility model in conjunction with the embodiments is to cover other options or modifications that may be derived based on the claims of this utility model. To provide a deep understanding of this utility model, many specific details will be included in the following description. This utility model may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this utility model, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0067] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0068] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0069] like Figure 1 As shown, Figure 1 A schematic diagram of the architecture of a battery management system for vehicles. Figure 1The battery management system (BMS) adopts a master-slave architecture. The vehicle includes a vehicle controller, which is connected to the master unit. The master unit includes: an MCU, power supply circuit, wake-up circuit, communication circuit (e.g., CAN communication circuit), relay drive circuit, general-purpose input / output (GPIO), electrically erasable programmable read-only memory (EEPROM), real-time clock (RTC), charging management circuit, collision management circuit, and high-voltage acquisition circuit. The high-voltage acquisition circuit includes an insulation detection circuit. The slave units include multiple analog front-end modules (AFE). The analog front-end modules detect the voltage and / or temperature information of the battery pack and transmit it to the master unit's MCU, which performs SOC calculations. This architecture often requires a dedicated MCU, resulting in high hardware costs and significant waste of MCU resources. Furthermore, due to the need for an additional MCU chip, the master-slave architecture also requires additional software development compatible with the MCU, leading to long development cycles and high costs.

[0070] like Figure 2 As shown, Figure 2 A schematic diagram of another battery management system architecture for vehicles. Figure 2 The battery management system (BMS) adopts an integrated architecture. The vehicle includes a vehicle controller, which is connected to the integrated BMS. The integrated BMS includes: an MCU, power supply circuit, wake-up circuit, communication circuit (e.g., CAN communication circuit), relay drive circuit, general purpose input / output interface, non-volatile memory, real-time clock circuit, charging management circuit, collision management circuit, and high-voltage acquisition circuit. The high-voltage acquisition circuit includes an insulation detection circuit. The MCU of the integrated BMS is connected to multiple analog front-end modules. These modules acquire voltage and / or temperature information from the battery pack and transmit this information to the MCU, which then performs SOC calculations. This architecture also requires an MCU, resulting in relatively high hardware costs. Furthermore, it necessitates the design of software compatible with the MCU, leading to high software development costs and long development cycles.

[0071] like Figure 3As shown, in a first aspect, the present invention provides a battery management system for a vehicle, the vehicle including a vehicle controller 3, the battery management system including a high-voltage unit 1, including a high-voltage acquisition chip circuit 11 and an analog front-end module 12, the high-voltage acquisition chip circuit 11 being used to acquire first detection information of the battery pack when the vehicle is in a non-low power mode, the analog front-end module 12 being used to acquire second detection information of the battery pack when the vehicle is in a low power mode, wherein the first detection information includes one or more of voltage, current, relay status and insulation status, and the second detection information includes voltage and / or temperature.

[0072] The battery management system also includes a low-voltage unit 2, which includes a communication conversion chip circuit 21 and a communication circuit 22. The communication conversion chip circuit 21 is used to receive first detection information and second detection information transmitted to it through a daisy chain, and transmit the first detection information and second detection information to the vehicle controller 3 through the communication circuit 22.

[0073] Low-power mode is a working state that reduces the energy consumption of the battery management system by minimizing unnecessary hardware operations and optimizing power management. Non-low-power mode, also known as normal operating mode, is the operating state of the vehicle when the vehicle controller is activated, during normal use. In this mode, the battery management system fully activates its hardware and software functions to ensure that the vehicle can monitor battery pack information in real time. The high-voltage acquisition chip circuit 11 collects the first detection information of the battery pack, and the analog front-end module 12 collects the second detection information of the battery pack.

[0074] The high-voltage acquisition chip circuit 11 provided in this application can acquire first detection information of the battery pack (e.g., including one or more of voltage, current, relay status, and insulation status) when the vehicle is in a non-low-power mode. The analog front-end module 12 can acquire the voltage and / or temperature of the battery pack when the vehicle is in both non-low-power and low-power modes. The communication conversion chip circuit 21 can receive the first and second detection information transmitted to it via a daisy chain and transmit the first and second detection information to the vehicle controller 3 via a communication circuit 22 (e.g., CAN communication or CAN FD communication). On the one hand, from a hardware perspective, the mode decision-making function of the traditional MCU is transferred to the vehicle's existing vehicle controller 3. Compared with the prior art, the MCU in the traditional battery management system is eliminated, reducing costs and thus simplifying the hardware structure and achieving effective cost control. On the other hand, from a software perspective, the vehicle controller 3 makes the decisions, and the battery management system (BMS) is only responsible for acquiring and transmitting detection information. There is no need to develop MCU-related software, reducing software development costs and time. Specifically, data acquisition is achieved by the high-voltage acquisition chip circuit 11 and the analog front-end module 12, requiring only hardware parameter configuration without software programming. Communication transmission is handled by the hardware protocol of the communication conversion chip circuit 21. The communication conversion chip circuit 21 receives the first and second detection information through a daisy link, and performs format conversion internally without the need for software drivers. The vehicle controller itself has data processing capabilities, and can determine whether the vehicle is in non-low power mode or low power mode without the need for additional software development. This results in a simple, low-cost, and highly adaptable battery management system that does not require an additional MCU.

[0075] In some embodiments, the analog front-end module 12 collects voltage, current, and temperature information of the battery pack. The analog front-end module 12 can collect the battery pack voltage, charging / discharging current, and temperature. The analog front-end module 12 can also collect the voltage, charging / discharging current, and temperature of individual battery cells.

[0076] In some embodiments, the analog front-end module 12 collects voltage, current, and temperature information of the battery pack in both low-power and non-low-power modes.

[0077] According to another specific embodiment of the present invention, the vehicle controller 3 is used to respond to the first detection information to determine the SOC of the battery pack and / or to determine whether a thermal runaway fault has occurred, and / or, the vehicle controller 3 is used to respond to the second detection information to determine whether the vehicle has switched from a low-power mode to a non-low-power mode.

[0078] In the above embodiments, the vehicle controller 3 responds to determine the SOC of the battery pack and / or whether a thermal runaway fault has occurred based on one or more of the battery pack's voltage, current, relay status, and insulation status. The vehicle controller 3 can accurately calculate the SOC of the battery pack based on one or more of the battery pack's voltage, current, relay status, and insulation status, gaining a more comprehensive understanding of the battery pack's health and operating status, and monitoring and judging the battery pack's status; and / or, in response to determining whether a thermal runaway fault has occurred based on one or more of the battery pack's voltage, current, relay status, and insulation status, the vehicle controller 3 determines whether thermal runaway has occurred based on first detection information. Once it is determined that thermal runaway may occur, the vehicle controller can immediately take corresponding measures, such as cutting off relevant circuits, to react more quickly.

[0079] Continue to refer to Figure 3 According to another specific embodiment of the present invention, the low-voltage unit 2 further includes: a reverse wake-up circuit 23, wherein the output terminal of the communication conversion chip circuit 21 is connected to the input terminal of the reverse wake-up circuit 23, and the output terminal of the reverse wake-up circuit 23 is connected to the input terminal of the vehicle controller 3; when the analog front-end module 12 detects that the second detection information exceeds the preset thermal runaway threshold, the analog front-end module 12 outputs a first output signal to the communication conversion chip circuit 21, the communication conversion chip circuit 21 outputs a first control signal to the reverse wake-up circuit 23, and the reverse wake-up circuit 23 outputs a second control signal to wake up the vehicle controller 3, so that the vehicle switches from low-power mode to non-low-power mode.

[0080] In the above embodiments, when the simulation front-end module 12 detects that the voltage or temperature of the battery pack exceeds the preset thermal runaway threshold, the simulation front-end module 12 outputs a first output signal to the communication conversion chip circuit 21. The communication conversion chip circuit 21 outputs a first control signal to the reverse wake-up circuit 23. The reverse wake-up circuit 23 outputs a second control signal to wake up the vehicle controller 3. The vehicle controller performs thermal runaway judgment, and the vehicle switches from low-power mode to non-low-power mode. In low-power mode, only the simulation front-end module 12 of the battery management system works. When the vehicle experiences thermal runaway, the reverse wake-up circuit 23 wakes up the vehicle controller 3, and the vehicle controller 3 wakes up the remaining units of the battery management system. The remaining units of the battery management system only work in non-low-power mode, saving vehicle energy consumption. When a thermal runaway fault is detected, the battery management system will promptly wake up the vehicle controller 3 and trigger a thermal runaway alarm. When the vehicle controller 3 determines that a thermal runaway-related fault has occurred, the wake-up circuit 24 will actively wake up the battery management system to achieve real-time monitoring of the battery.

[0081] Specifically, in low-power mode, only the analog front-end module 12 operates, responsible for collecting the voltage and / or temperature of the battery pack, which significantly reduces the overall energy consumption of the system. The analog front-end module 12 continuously monitors the voltage and / or temperature of the battery pack in low-power mode. The reverse wake-up circuit 23 receives the first control signal from the communication conversion chip circuit 21, waking up the vehicle controller 3. The vehicle controller 3 determines that if a thermal runaway fault occurs, it switches the vehicle from low-power mode to a non-low-power mode. Only then will other units of the battery management system activate, and the high-voltage acquisition chip circuit 11 collects the first detection information, namely one or more of voltage, current, relay status, and insulation status, to obtain more comprehensive battery pack data. This reverse wake-up method minimizes unnecessary energy consumption.

[0082] According to another specific embodiment of the present invention, refer to Figure 3 and Figure 4 The battery management system includes a battery 4, which provides a first voltage V1. The low-voltage unit 2 also includes a filter protection anti-reverse circuit 25, which includes: a voltage output terminal PFIL11 for outputting a second voltage V2, which is the filtered voltage; a filter module including a first capacitor bank, a first inductor L1, and a second capacitor bank. One end of the first inductor L1 is connected to the anode of the first capacitor bank, and the other end of the first inductor L2 is connected to the anode of the second capacitor bank. The anode of the second capacitor bank is connected to the voltage output terminal PFIL11, and the cathode of the second capacitor bank is connected to the ground terminal GND. The first capacitor bank includes capacitors C1, C2, C3, and C4 connected in parallel. The second capacitor bank includes capacitors C5, C6, C7, and C8 connected in parallel. An anti-reverse module D1 is included, with its anode connected to the positive terminal KL30 of the battery and its cathode connected to the anode of the first capacitor bank of the filter module, to prevent the battery 4 from being connected in reverse and damaging components in the circuit. The anti-reverse module D1 is, for example, a diode. Surge absorption module D2 is configured to absorb surge signals. The anode of surge absorption module D2 is connected to the cathode of anti-reverse module D1, and the cathode of surge absorption module D2 is connected to the negative terminal KL31 of the battery 4. Surge absorption module D2 is, for example, a TVS diode. Under normal operating voltage, the TVS diode exhibits high impedance and is almost non-conductive, having little impact on the normal operation of the circuit. When a transient high-voltage spike occurs in the circuit, the voltage across the TVS diode exceeds its breakdown voltage, and the TVS diode quickly changes from a high-impedance state to a low-impedance state. During this process, the TVS diode rapidly absorbs the energy of the transient high voltage and conducts the overcurrent to ground through a low-impedance path, thereby protecting the subsequent circuitry.

[0083] Using the above technical solution, the filter protection and anti-reverse circuit 25 can filter the first voltage V1 output by the battery 4, prevent the battery 4 from being connected in reverse and damaging the components in the circuit, absorb surge signals, and protect the downstream circuit.

[0084] According to another specific embodiment of the present invention, refer to Figure 3 and Figure 5 The low-voltage unit 2 includes a reverse wake-up circuit 23, which comprises: a first transistor Q2, the base of which is connected to the output of the communication conversion chip circuit 21, and the collector of which is connected to ground; and a second transistor Q1, the base of which is connected to the emitter of the first transistor Q2, and the emitter of the second transistor Q1 is connected to the voltage output terminal PFIL11, which provides a second voltage V2 to the reverse wake-up circuit 23. The collector of the second transistor Q1 is connected to the vehicle controller 3. When the communication conversion chip circuit 21 receives a first output signal from the analog front-end module 12, the first control signal output by the communication conversion chip circuit 21 is high, the first transistor Q2 is turned on, the emitter of the first transistor Q2 is high, the second transistor Q1 is turned on, and the collector of the second transistor Q1 outputs a second control signal to wake up the vehicle controller 3.

[0085] Using the above technical solution, the communication conversion chip circuit 21 outputs a high-level first control signal, which turns on the first transistor Q2. The emitter of the first transistor Q2 is connected to the base of the second transistor Q1, turning on the second transistor Q1. The emitter of the second transistor Q1 is pulled high, and the collector of the second transistor Q1 outputs a second control signal to wake up the vehicle controller 3. The first transistor Q2 and the second transistor Q1 have fast response speeds, making them suitable for transient signal processing and enabling rapid wake-up of the vehicle controller. Resistors R1, R2, and R3 prevent short circuits. Capacitor C9 stabilizes the voltage. Diode D3 ensures unidirectional current flow and prevents reverse current.

[0086] According to another specific embodiment of the present invention, refer to Figure 3 and Figure 6The high-voltage unit 1 also includes a relay diagnostic circuit 14, which is connected to the high-voltage acquisition chip circuit 11 and is used to acquire the relay status of the battery pack. The relay diagnostic circuit 14 includes: a voltage input terminal VHX; a third voltage divider resistor R4, the first end of which is connected to the voltage input terminal VHX, and the second end of which is connected to the high-voltage acquisition chip circuit 11. Specifically, it is connected to the GPIO port of the high-voltage acquisition chip in the high-voltage acquisition chip circuit 11, and the high-voltage acquisition chip model is MC33772; a fourth voltage divider resistor R5, the first end of which is connected to the second end of the third voltage divider resistor R4; a relay M1, the first end of which is connected to the second end of the fourth voltage divider resistor R5, and the second end of the relay M1 is connected to the negative terminal BAT- of the battery pack; and a fifth voltage divider resistor R6, the first end of which is connected to the second end of the third voltage divider resistor R4, and the second end of the fifth voltage divider resistor R6 is connected to the negative terminal BAT- of the battery pack. By inputting voltage to the voltage input terminal VHX, the relay is determined to be either on or off based on the voltage value acquired by the high voltage acquisition chip circuit 11.

[0087] Specifically, when a voltage is input to the voltage input terminal VHX, if the relay is in the on state, the voltage at the GPIO port of the high-voltage acquisition chip in the high-voltage acquisition chip circuit 11 is the first voltage division result of the parallel connection of the fourth voltage divider resistor R5 and the fifth voltage divider resistor R6. If the relay is in the off state, the voltage at the GPIO port of the high-voltage acquisition chip in the high-voltage acquisition chip circuit 11 is the second voltage division result of the fifth voltage divider resistor R6. Since the total resistance of the parallel connection of the fourth voltage divider resistor R5 and the fifth voltage divider resistor R6 is less than the resistance of the fifth voltage divider resistor R6, the second voltage division result is greater than the first voltage division result. Based on the magnitude of the voltage acquired at the GPIO port of the high-voltage acquisition chip, it is determined whether the relay is in the on or off state. Diodes D4 and D5 prevent reverse current from damaging the relay. Capacitors C10 and C11 serve as voltage regulators.

[0088] According to another specific embodiment of the present invention, refer to Figure 3 The high-voltage unit 1 also includes a current detection circuit (current acquisition circuit) 16, which is connected to the high-voltage acquisition chip circuit 11 and is used to acquire the current of the battery pack. (Reference) Figure 7The current detection circuit includes: a shunt sensor (Shunt), a first filter circuit C12, a second filter circuit C13, a third filter circuit C14, a fourth filter circuit C15, a first voltage divider resistor R7, a second voltage divider resistor R8, a first reverse protection circuit, a second reverse protection circuit, and a fifth filter circuit. The first reverse protection circuit includes diodes D6 and D7, and the second reverse protection circuit includes diodes D8 and D9. These two circuits prevent excessive voltage from damaging circuit components. The fifth filter circuit includes a first capacitor C16 and a second capacitor C17. The anode of the first capacitor C16 is connected to the first terminal of the shunt sensor (Shunt), and the anode of the second capacitor C17 is connected to the second terminal of the shunt sensor (Shunt). The cathodes of the first capacitor C16 and the second capacitor C17 are both connected to the negative terminal (Bat-) of the battery pack. In this circuit, the first terminal of the shunt sensor (Shunt) is connected to the high-voltage acquisition chip circuit 11 via the first voltage-dividing resistor R7, and the second terminal of the shunt sensor (Shunt) is connected to the high-voltage acquisition chip circuit 11 via the second voltage-dividing resistor R8. The anode of the first filter circuit C12 is connected to the first terminal of the shunt sensor (Shunt), and the cathode of the first filter circuit C12 is connected to the negative terminal (Bat-) of the battery pack. The anode of the second filter circuit C13 is connected to the second terminal of the shunt sensor (Shunt), and the cathode of the second filter circuit C13 is connected to the negative terminal (Bat-) of the battery pack. The third filter circuit... The anode of C14 is connected to the first terminal of the first voltage divider resistor R7. The cathode of the third filter circuit C14 is connected to the negative terminal Bat- of the battery pack. The anode of the fourth filter circuit C15 is connected to the first terminal of the second voltage divider resistor R8, and the cathode of the fourth filter circuit C15 is connected to the negative terminal Bat- of the battery pack. The anode of the first anti-reverse circuit is connected to the first terminal of the shunt sensor, and the cathode of the first anti-reverse circuit is connected to the negative terminal Bat- of the battery pack. The anode of the second anti-reverse circuit is connected to the second terminal of the shunt sensor, and the cathode of the second anti-reverse circuit is connected to the negative terminal Bat- of the battery pack. The high-voltage acquisition chip circuit 11 calculates the current of the battery pack based on the voltage across the shunt sensor. The second terminal of the first voltage divider resistor R7 is connected to the first terminal of the shunt sensor, and the second voltage divider resistor R8 is connected to the second terminal of the shunt sensor.

[0089] Using the above technical solution, the first filter circuit C12, the second filter circuit C13, the third filter circuit C14, the fourth filter circuit C15, and the fifth filter circuit perform filtering functions. The first voltage divider resistor R7 and the second voltage divider resistor R8 prevent excessive current from damaging the high-voltage acquisition chip in the high-voltage acquisition chip circuit 11. The first reverse protection circuit includes diodes D6 and D7, and the second reverse protection circuit includes diodes D8 and D9. The first and second reverse protection circuits are used to prevent excessive voltage from damaging circuit components and to protect the circuit. The fifth filter circuit filters and stabilizes the voltage across the shunt sensor. The anode of the ninth filter circuit C18 is connected to the first terminal of the first voltage divider resistor R7, and the cathode of the ninth filter circuit C18 is connected to the first terminal of the second voltage divider resistor R8, thus stabilizing the voltage of the high-voltage acquisition chip circuit 11. The second terminal of the first voltage divider resistor R7 is connected to the first terminal of the shunt sensor, and the second voltage divider resistor R8 is connected to the second terminal of the shunt sensor. Since the shunt sensor is connected to the negative terminal Bat- of the battery pack, the high-voltage acquisition chip in the high-voltage acquisition chip circuit 11 acquires the differential voltage across the shunt sensor. By calculating the differential voltage, the current of the shunt sensor is calculated, and thus the current of the battery pack is obtained.

[0090] According to another specific embodiment of this utility model, please continue to refer to... Figure 3 The communication conversion chip circuit includes the MC33665 chip. Using the MC33665 chip, the first and / or second detection information of daisy-chain communication can be converted into CAN communication or CAN FD communication without the need for an MCU, and then transmitted to the vehicle controller 3 via communication circuit 22.

[0091] The above technical solution eliminates the need for an MCU structure, resulting in a simple, low-cost battery management system that requires no additional software programming.

[0092] According to another specific embodiment of this utility model, the communication circuit 22 includes CAN communication or CAN FD communication. Using the above technical solution, the communication circuit 22 has high reliability and real-time performance, fast data transmission, and significantly improved communication efficiency through higher transmission rates and longer data frame lengths.

[0093] According to another specific embodiment of the present invention, refer to Figure 3The low-voltage unit also includes: a wake-up circuit 24, a power supply circuit 26, and an isolation power supply circuit 27. When the reverse wake-up circuit 23 outputs a second control signal to wake up the vehicle controller 3, the vehicle controller 3 outputs a third control signal to activate the wake-up circuit 24. The wake-up circuit 24 outputs a fourth control signal to activate the power supply circuit 26 and the isolation power supply circuit 27. The power supply circuit 26 supplies power to the high-voltage acquisition chip circuit 11 through the isolation power supply circuit 27.

[0094] According to another specific embodiment of the present invention, refer to Figure 3 and Figure 8 The isolated power supply circuit 27 includes: a driver chip IC1, including a first output port D10, a second output port D11, a power supply terminal VCC, and a control port CLK. The power supply terminal VCC is used to provide the third voltage V3 output by the power supply circuit. A transformer T1 is connected to the first output port D10 and the second output port D11 respectively. The transformer T1 includes a first primary winding P1 and a first secondary winding S1, as well as a second primary winding P2 and a second secondary winding S2. A first anti-reverse circuit D12 and a second anti-reverse circuit D13 are provided. The first anti-reverse circuit D12 is connected to the first secondary winding S1, and the second anti-reverse circuit D13 is connected to the second secondary winding S2. The first anti-reverse circuit D12 and the second anti-reverse circuit D13 are respectively configured to provide the fourth voltage V4 to the load terminal VISO. A sixth filter circuit C19 is provided. The anode of the sixth filter circuit C19 is connected to the first output port D10, and the cathode of the sixth filter circuit C19 is connected to the ground terminal GND. The seventh filter circuit C20 has its anode connected to the second output port D11 and its cathode connected to ground GND. The eighth filter circuit includes capacitors C21 and C22. The anode of the eighth filter circuit is connected to the power supply terminal VCC, and its cathode is connected to ground GND. When the wake-up circuit 24 outputs the fourth control signal, causing the driver chip's control port CLK to go high, the first output port D10 and the second output port D11 alternately output voltage signals, exciting the corresponding primary winding so that the corresponding secondary winding can generate an induced voltage.

[0095] Using the above technical solution, the isolation power supply circuit can convert the third voltage V3 output by the power supply circuit 26 in the low-voltage unit 2 into a high-voltage fourth voltage V4, which powers the high-voltage acquisition chip circuit 11 of the high-voltage unit 1 and provides a stable high-voltage voltage.

[0096] In some embodiments, the driver chip of the isolation power supply circuit 27 is of model SN6505 or SN6505BDBVT.

[0097] According to another specific embodiment of this utility model, the low-voltage unit 2 of the battery management system further includes a relay drive circuit 28 for controlling the on and off states of the relay. The communication conversion chip circuit 21 includes a GPIO output port, which is connected to the relay drive circuit. When the battery pack is charging or discharging, the GPIO output port is at a high level, and the relay drive circuit 28 controls the relay to turn on. When the battery pack is not charging or discharging, the GPIO output port is at a low level, and the relay drive circuit 28 controls the relay to turn off.

[0098] By adopting the above technical solution, the relay is directly controlled by the GPIO signal to realize the rapid and reliable connection or disconnection between the battery pack and the external circuit. This avoids the delay and wear of manual operation or mechanical switches. The relay is automatically disconnected when not charging or discharging to prevent accidental discharge or overcharging of the battery pack and reduce the risk of thermal runaway.

[0099] According to another specific embodiment of this utility model, such as Figure 3 As shown, the high-voltage unit 1 also includes a voltage acquisition circuit 13 for acquiring voltage information from the battery pack. Figure 9 As shown, the voltage acquisition circuit 13 includes: a sixth voltage divider resistor R9, the first end of which is connected to the positive terminal of the battery pack; a seventh voltage divider resistor R10, the first end of which is connected to the second end of the sixth voltage divider resistor R9, the first end of which is connected to the high voltage acquisition chip circuit 11, and the second end of which is connected to the negative terminal Bat- of the battery pack; wherein, the resistance value of the sixth voltage divider resistor R9 is greater than the resistance value of the seventh voltage divider resistor R10.

[0100] By adopting the above technical solution, the resistance value of the sixth voltage divider resistor R9 is greater than that of the seventh voltage divider resistor R10. The sixth voltage divider resistor R9 is used to divide the voltage, thereby reducing the voltage of the high voltage acquisition chip circuit 11 and preventing the high voltage acquisition chip circuit 11 from being damaged by excessively high voltage.

[0101] refer to Figure 3 and Figure 10The high-voltage unit 1 also includes an insulation detection circuit 15. The insulation detection circuit 15 uses the unbalanced bridge principle to perform insulation detection on the battery pack. The positive (Bat+) and negative (Bat-) terminals of the battery are connected to the circuit, and KL31 is the vehicle's reference ground. The positive resistor Rp and the negative resistor Rn represent the insulation resistance of the positive and negative terminals, respectively. The insulation detection circuit also includes a first switch S3, a second switch S4, and a third switch S5 to change the circuit connection method. Resistors R11, R12, R13, R14, and R0 are fixed resistors with known resistance values. When the battery pack is working normally, the resistance values ​​of the positive resistor Rp and the negative resistor Rn are high, indicating good insulation performance, the bridge is in a balanced state, and the voltage at the GPIO input is close to zero. If the insulation performance of the battery pack deteriorates (e.g., due to leakage), the resistance values ​​of the positive resistor Rp and the negative resistor Rn will decrease, which will cause the bridge to become unbalanced, and the voltage at the GPIO input will change. The MC33772 chip in the high-voltage acquisition chip circuit monitors the voltage at the GPIO input terminal. When the detected voltage exceeds a preset threshold, the vehicle controller can trigger an alarm or other protection measures to indicate that there is an insulation fault in the battery pack.

[0102] refer to Figure 3 and Figure 11 When the vehicle controller switches the vehicle from low-power mode to non-low-power mode, the vehicle controller 3 outputs a third control signal, Wake in, to the wake-up circuit 24. The wake-up circuit 24 outputs a fourth control signal, S_wake, which is input to the control port EN of the power supply circuit 26. The power supply circuit outputs a third voltage, V3, at its Vcc5V ​​output terminal. Capacitors C23, C24, and C25 are used for filtering and voltage regulation.

[0103] Using the above technical solution, the power supply circuit 26 can be woken up after receiving the fourth control signal and continuously output the third voltage V3.

[0104] Although the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the present invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the present invention to these descriptions. Those skilled in the art can make various changes in form and detail, including some simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A battery management system for a vehicle, the vehicle including a vehicle controller, characterized in that, include: The high-voltage unit includes a high-voltage acquisition chip circuit and an analog front-end module. The high-voltage acquisition chip circuit is used to acquire first detection information of the battery pack when the vehicle is in a non-low-power mode. The analog front-end module is used to acquire second detection information of the battery pack when the vehicle is in both the non-low-power mode and the low-power mode. The first detection information includes one or more of voltage, current, relay status and insulation status. The second detection information includes voltage and / or temperature. The low-voltage unit includes a communication conversion chip circuit and a communication circuit. The communication conversion chip circuit is used to receive the first detection information and the second detection information transmitted to it via a daisy chain, and to transmit the first detection information and the second detection information to the vehicle controller via the communication circuit.

2. The battery management system for a vehicle as described in claim 1, characterized in that, The vehicle controller is configured to respond to the first detection information to determine the SOC of the battery pack and / or to determine whether a thermal runaway fault has occurred, and / or the vehicle controller is configured to respond to the second detection information to determine whether to switch the vehicle from the low-power mode to the non-low-power mode.

3. The battery management system for a vehicle as described in claim 2, characterized in that, The low-voltage unit further includes: a reverse wake-up circuit. The output terminal of the communication conversion chip circuit is connected to the input terminal of the reverse wake-up circuit, and the output terminal of the reverse wake-up circuit is connected to the input terminal of the vehicle controller. When the simulated front-end module detects that the second detection information exceeds the preset thermal runaway threshold, the simulated front-end module outputs a first output signal to the communication conversion chip circuit, the communication conversion chip circuit outputs a first control signal to the reverse wake-up circuit, and the reverse wake-up circuit outputs a second control signal to wake up the vehicle controller, so that the vehicle switches from the low-power mode to the non-low-power mode.

4. The battery management system for a vehicle as described in claim 3, characterized in that, The battery management system includes a storage battery, and the low-voltage unit further includes a filter protection and reverse polarity protection circuit, which includes: A voltage output terminal is used to output a second voltage, which is a filtered voltage. The filtering module includes a first capacitor bank, a first inductor, and a second capacitor bank. One end of the first inductor is connected to the anode of the first capacitor bank, and the other end of the first inductor is connected to the anode of the second capacitor bank. The anode of the second capacitor bank is connected to the voltage output terminal, and the cathode of the second capacitor bank is connected to the ground terminal. An anti-reverse module is provided, wherein the anode of the anti-reverse module is connected to the positive terminal of the battery, and the cathode of the anti-reverse module is connected to the anode of the first capacitor bank of the filter module, for preventing the battery from being connected in reverse and damaging the components in the circuit. A surge absorption module is configured to absorb surge signals. The anode of the surge absorption module is connected to the cathode of the anti-reverse module, and the cathode of the surge absorption module is connected to the negative terminal of the battery.

5. The battery management system for a vehicle as described in claim 4, characterized in that, The low-voltage unit includes a reverse wake-up circuit, which includes: The base of the first transistor is connected to the output terminal of the communication conversion chip circuit, and the collector of the first transistor is connected to the ground terminal. The base of the second transistor is connected to the emitter of the first transistor, and the emitter of the second transistor is connected to the voltage output terminal, which is used to provide a second voltage for the reverse wake-up circuit. The collector of the second transistor is connected to the vehicle controller. When the communication conversion chip circuit receives the first output signal from the analog front-end module, the first control signal output by the communication conversion chip circuit is high level, the first transistor is turned on, the emitter of the first transistor is high level, the second transistor is turned on, and the collector of the second transistor outputs a second control signal to wake up the vehicle controller.

6. The battery management system for a vehicle as described in claim 1, characterized in that, The high-voltage unit further includes a relay diagnostic circuit, which is connected to the high-voltage acquisition chip circuit and is used to acquire the relay status of the battery pack. The relay diagnostic circuit includes: Voltage input terminal; The third voltage divider resistor has its first end connected to the voltage input terminal and its second end connected to the high voltage acquisition chip circuit. The fourth voltage divider resistor, the first end of which is connected to the second end of the third voltage divider resistor; A relay, wherein the first terminal of the relay is connected to the second terminal of the fourth voltage divider resistor, and the second terminal of the relay is connected to the negative terminal of the battery pack; The fifth voltage divider resistor has its first end connected to the second end of the third voltage divider resistor, and its second end connected to the negative terminal of the battery pack. By inputting voltage to the voltage input terminal, the system determines whether the relay is on or off based on the voltage value acquired by the high-voltage acquisition chip circuit.

7. The battery management system for a vehicle as described in claim 1, characterized in that, The high-voltage unit further includes a current detection circuit, which is connected to the high-voltage acquisition chip circuit and is used to acquire the current of the battery pack. The current detection circuit includes: The shunt sensor includes a first filter circuit, a second filter circuit, a third filter circuit, a fourth filter circuit, a first voltage divider resistor, a second voltage divider resistor, a first anti-reverse circuit, a second anti-reverse circuit, and a fifth filter circuit. The fifth filter circuit includes a first capacitor and a second capacitor. The anode of the first capacitor is connected to the first terminal of the shunt sensor, and the anode of the second capacitor is connected to the second terminal of the shunt sensor. The cathodes of the first capacitor and the second capacitor are connected to the negative terminal of the battery pack. In this circuit, the first terminal of the shunt meter sensor is connected to the high-voltage acquisition chip circuit via a first voltage-dividing resistor; the second terminal of the shunt meter sensor is connected to the high-voltage acquisition chip circuit via a second voltage-dividing resistor; the anode of the first filter circuit is connected to the first terminal of the shunt meter sensor; the cathode of the first filter circuit is connected to the negative terminal of the battery pack; the anode of the second filter circuit is connected to the second terminal of the shunt meter sensor; the cathode of the second filter circuit is connected to the negative terminal of the battery pack; the anode of the third filter circuit is connected to the first terminal of the first voltage-dividing resistor; the cathode of the third filter circuit is connected to the negative terminal of the battery pack; the anode of the fourth filter circuit is connected to the first terminal of the second voltage-dividing resistor; the cathode of the fourth filter circuit is connected to the negative terminal of the battery pack; the anode of the first anti-reverse circuit is connected to the first terminal of the shunt meter sensor; the cathode of the first anti-reverse circuit is connected to the negative terminal of the battery pack; the anode of the second anti-reverse circuit is connected to the second terminal of the shunt meter sensor; and the cathode of the second anti-reverse circuit is connected to the negative terminal of the battery pack. The high-voltage acquisition chip circuit calculates the current of the battery pack based on the voltage across the shunt sensor.

8. The battery management system for a vehicle as described in claim 1, characterized in that, The communication conversion chip circuit includes an MC33665 chip, and / or the communication circuit includes CAN communication or CAN FD communication.

9. The battery management system for a vehicle as described in claim 5, characterized in that, The low-voltage unit further includes: a wake-up circuit, a power supply circuit, and an isolation power supply circuit. Specifically, when the reverse wake-up circuit outputs a second control signal to wake up the vehicle controller, the vehicle controller outputs a third control signal to activate the wake-up circuit, and the wake-up circuit outputs a fourth control signal to activate the power supply circuit and the isolation power supply circuit. The power supply circuit supplies power to the high-voltage acquisition chip circuit through the isolation power supply circuit. The isolation power supply circuit includes: The driver chip includes a first output port, a second output port, a power supply terminal, and a control port, wherein the power supply terminal is used to provide a third voltage output by the power supply circuit; A transformer is connected to the first output port and the second output port respectively. The transformer includes a first primary winding and a first secondary winding, as well as a second primary winding and a second secondary winding. The third anti-reverse circuit and the fourth anti-reverse circuit are respectively configured to provide induced voltage to the load terminal. The third anti-reverse circuit is connected to the first secondary winding, and the fourth anti-reverse circuit is connected to the second secondary winding. A sixth filter circuit, wherein the anode of the sixth filter circuit is connected to the first output port, and the cathode of the sixth filter circuit is connected to the ground terminal; A seventh filter circuit, wherein the anode of the seventh filter circuit is connected to the second output port, and the cathode of the seventh filter circuit is connected to the ground terminal; The eighth filter circuit has its anode connected to the power supply terminal and its cathode connected to the ground terminal. When the wake-up circuit outputs a fourth control signal, causing the control port of the driver chip to be at a high level, the first output port and the second output port alternately output voltage signals to excite the corresponding primary winding, so that the corresponding secondary winding can generate the induced voltage.

10. The battery management system for a vehicle as claimed in claim 1, characterized in that, The battery management system also includes a relay drive circuit for controlling the on and off of the relays; The communication conversion chip circuit includes a GPIO output port, which is connected to the relay driving circuit. When the GPIO output port is high, the relay driving circuit controls the relay to turn on; when the GPIO output port is low, the relay driving circuit controls the relay to turn off. And / or, The high-voltage unit further includes a voltage acquisition circuit for acquiring voltage information of the battery pack. The voltage acquisition circuit includes: The sixth voltage divider resistor, the first end of which is connected to the positive terminal of the battery pack; The seventh voltage divider resistor has its first end connected to the second end of the sixth voltage divider resistor, its first end connected to the high voltage acquisition chip circuit, and its second end connected to the negative terminal of the battery pack. The resistance of the sixth voltage divider resistor is greater than that of the seventh voltage divider resistor.

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