A battery pack safety start-stop and automatic hibernate circuit

Abstract

The application discloses a battery pack safety start-stop and automatic hibernation circuit. The MOS tube is connected between an output end of the battery pack and an input end of a switching power supply; a start control module is used for controlling the MOS tube to be turned on according to the action of a first start switch; a normal state control module is connected with the gate of the MOS tube and a voltage stabilizing module; the input end of an isolation control module is used for inputting a control signal of a battery management system; the output end of the isolation control module and the voltage stabilizing module are connected in series between two output ends of the switching power supply; the isolation control module is used for controlling the MOS tube to be continuously turned on together with the normal state control module when a normal working signal is inputted to the input end; and the isolation control module is also used for controlling the MOS tube to be turned off together with the normal state control module when a hibernation signal is inputted to the input end. The technical scheme provided by the embodiment of the application can provide a general, low-consumption, economical, miniaturizable and safe start / stop / automatic hibernation circuit and device for any high-voltage lithium battery pack.

Description

Technical Field

[0001] This invention relates to the field of power battery technology, and in particular to a battery pack safety start-stop and automatic sleep circuit. Background Technology

[0002] High-voltage lithium battery packs with automatic sleep function generally have three functions: power-on, power-off, and automatic sleep, forming a complex control logic relationship. Typically, they consist of a pair of normally open and normally closed switches with self-resetting function, and a relay controlled by the lithium battery management system (BMS) program. These are combined in series and parallel to form a composite switch, which is connected in series to the input circuit of a DC switching power supply directly connected to the high-voltage lithium battery. This allows control of the switching power supply's on / off state, thereby realizing the start / stop / programmed sleep function of the high-voltage lithium battery pack itself.

[0003] However, this method of directly connecting the composite switch in series with the high-voltage input circuit of the switching power supply forces both manual switches to withstand the full high voltage of the lithium battery pack. This not only complicates and makes the selection of components more difficult and less universal, but also reduces the safety performance of the lithium battery pack operation. Summary of the Invention

[0004] This invention provides a battery pack safety start-stop and automatic sleep circuit to solve the problem that the start-stop circuit of a high-voltage lithium battery pack with automatic sleep function must withstand high voltage, which makes the selection of components complicated, difficult, and difficult to be universal, and also reduces the safety performance of lithium battery pack operation.

[0005] According to one aspect of the present invention, a battery pack safety start-stop and automatic sleep circuit is provided, comprising: a MOSFET, a start-up control module, a normal control module, an isolation control module, and a voltage regulator module;

[0006] The MOSFET is connected between an output terminal of the battery pack and an input terminal of the switching power supply, which is used to supply power to the battery management system.

[0007] The startup control module includes a first startup switch, and the startup control module is used to control the MOSFET to turn on according to the action of the first startup switch;

[0008] The normal control module connects the gate of the MOSFET and the voltage regulator module. The input terminal of the isolation control module is used to input the control signal of the battery management system. The output terminal of the isolation control module and the voltage regulator module are connected in series between the two output terminals of the switching power supply. When a normal operation signal is input to the input terminal, the isolation control module, together with the normal control module, controls the MOSFET to remain on. The isolation control module is also used to control the MOSFET to turn off when a sleep signal is input to the input terminal.

[0009] Optionally, the startup control module includes a first diode, a first switch, and a first power supply;

[0010] The cathode of the first diode is connected to the gate of the MOSFET, the anode of the first diode is connected to the first terminal of the first switch, and the second terminal of the first switch is connected to the first power supply.

[0011] Optionally, the first switch includes a self-resetting normally open manual switch.

[0012] Optionally, the voltage regulation of the voltage regulator module is greater than the output voltage of the first power supply.

[0013] Optionally, the output voltage of the switching power supply is greater than the output voltage of the first power supply.

[0014] Optionally, the normal control module includes a second diode and a second switch. The negative terminal of the second diode is connected to the gate of the MOSFET, the positive terminal of the second diode is connected to the first terminal of the second switch, and the second terminal of the second switch is connected to the voltage regulator module.

[0015] Optionally, the second switch may include a self-resetting normally closed manual switch.

[0016] Optionally, the voltage regulator module includes a Zener diode, with the negative terminal of the Zener diode connected to the second terminal of the second switch and the positive terminal of the Zener diode connected to the negative output terminal of the switching power supply.

[0017] Optionally, the isolation control module includes an optocoupler, the input of which is connected to the battery management system; one end of the optocoupler's output is connected to the positive output of the switching power supply, and the other end of the optocoupler's output is connected to the voltage regulator module.

[0018] Optionally, the gate of the MOSFET is connected to a gate resistor.

[0019] The technical solution of this invention includes a MOSFET, a startup control module, a normal control module, an isolation control module, and a voltage regulator module. The MOSFET is connected between an output of the battery pack and an input of a switching power supply, which powers the battery management system. The startup control module includes a first startup switch, which controls the MOSFET to turn on based on the action of the first startup switch. The normal control module connects the gate of the MOSFET to the voltage regulator module. The input of the isolation control module receives control signals from the battery management system, and its output and the voltage regulator module are connected in series between the two outputs of the switching power supply. When a normal operation signal is input, the isolation control module, along with the normal control module, controls the MOSFET to remain on. The isolation control module also controls the MOSFET to turn off when a sleep signal is input. This solution solves the problem that the switches in the start / stop circuits of high-voltage lithium battery packs with automatic sleep functions must withstand high voltage, making device selection complex, difficult, and uncommon, and reducing the safety performance of the lithium battery pack operation. The technical solution provided by this invention provides a universal, low-power, economical, miniaturizable, and safe start / stop / automatic sleep circuit and device for any high-voltage lithium battery pack.

[0020] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a battery pack safety start-stop and automatic sleep circuit provided by an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of another battery pack safety start-stop and automatic sleep circuit provided according to an embodiment of the present invention; Detailed Implementation

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] Figure 1 This is a schematic diagram of a battery pack safety start-stop and automatic sleep circuit according to an embodiment of the present invention. This embodiment can be applied to the control of start-up, stop, and automatic sleep of high-voltage lithium battery packs.

[0027] refer to Figure 1 The battery pack safety start-stop and automatic sleep circuit provided in this embodiment of the invention includes: MOSFET 110, start-up control module 120, normal control module 130, isolation control module 140, and voltage regulator module 150.

[0028] Among them, MOSFET 110 is connected between an output terminal of the battery pack and an input terminal of the switching power supply, which is used to supply power to the battery management system.

[0029] The full English name of MOSFET is Metal Oxide Semiconductor Field Effect Transistor (MOS), which is a type of field-effect transistor belonging to the insulated-gate type. Therefore, MOSFETs are sometimes called insulated-gate field-effect transistors. In general electronic circuits, MOSFETs are usually used as electronic switches in amplifier circuits or switching circuits to control the on / off state of the circuit. In this embodiment of the invention, the MOSFET is a high-voltage MOSFET; one output terminal of the battery pack in this embodiment of the invention is the negative terminal of the high-voltage lithium battery pack; one input terminal of the switching power supply in this embodiment of the invention is the negative input terminal of the DC switching power supply.

[0030] The start control module 120 includes a first start switch, and the start control module 120 is used to control the MOSFET 110 to turn on according to the action of the first start switch;

[0031] The normal control module 130 is connected to the gate of the MOSFET 110 and the voltage regulator module 150. The input terminal of the isolation control module 140 is used to input the control signal of the battery management system. The output terminal of the isolation control module 140 and the voltage regulator module 150 are connected in series between the two output terminals of the switching power supply. When a normal operation signal is input at the input terminal, the isolation control module 140 and the normal control module 130 control the MOSFET 110 to remain on. The isolation control module 140 and the normal control module 130 also control the MOSFET 110 to turn off when a sleep signal is input at the input terminal.

[0032] In this embodiment, the normal control module 130 is connected in series between the gate of the MOSFET 110 and the voltage regulator module 150, and the normal control module 130 is connected in parallel with the startup control module 120. The control signal of the battery management system is a sleep signal in this embodiment, which is active low. The two output terminals of the switching power supply are the positive and negative output terminals of the switching power supply, respectively. The isolation control module 140 and the voltage regulator module 150 are connected in series between the two output terminals of the switching power supply. That is, one end of the isolation control module 140 is connected to the voltage regulator module 150, the other end of the isolation control module 140 is connected to the positive output terminal of the switching power supply, and the other end of the voltage regulator module 150 is connected to the negative output terminal of the switching power supply. The voltage regulator module 150 can effectively prevent the voltage fluctuation caused by the change in the current of the gate of the control terminal of the MOSFET 110 from affecting the circuit, so that the gate voltage of the control terminal of the MOSFET 110 can be kept constant.

[0033] The working principle of the battery pack safety start-stop and automatic sleep circuit provided in this embodiment of the invention is as follows: The initial start-up of the system is completed by the first start switch of the start control module 120. When the first start switch is pressed, the start control module 120 outputs a certain DC voltage, for example, 6V. This DC voltage is applied to the gate of the MOSFET 110 through the gate resistor R1, causing the MOSFET 110 to conduct. This, in turn, turns on the input circuit of the DC switching power supply connected in series with the MOSFET 110, starting the switching power supply. After a delay and stabilization, the switching power supply outputs a low-voltage DC power, starting the battery management system (BMS). After the battery management system (BMS) successfully completes its self-test, it sets the BMS sleep signal (active low). The high-level signal is converted into input current, turning on the isolation control module 140 and generating current. This current flows through the voltage regulator module 150, producing a stable 8.2V control voltage (which can be set as needed). The normal control module 130 then turns on and applies the control voltage to the gate of the MOSFET 110. Because the stable 8.2V control voltage generated by the voltage regulator module 150 is higher than the output voltage of the startup control module 120, the startup control module 120 does not turn on, thus preventing it from consuming power. At this time, even if the first startup switch is released, the MOSFET 110 will continue to conduct.

[0034] During normal system operation, when the Battery Management System (BMS) program detects a system sleep condition, it resets the BMS sleep signal (outputs a low level), thus reducing the output current of the isolation control module 140 to zero. At this time, the gate voltage of the MOSFET 110 drops to zero, and the MOSFET 110 is turned off, thereby disconnecting the input of the switching power supply. The BMS loses power, and the system achieves program shutdown.

[0035] The technical solution of this invention includes a MOSFET, a startup control module, a normal control module, an isolation control module, and a voltage regulator module. The MOSFET is connected between an output of the battery pack and an input of a switching power supply, which powers the battery management system. The startup control module includes a first startup switch and controls the MOSFET to turn on based on the action of the first startup switch. The normal control module connects the gate of the MOSFET to the voltage regulator module. The input of the isolation control module is used to input control signals from the battery management system, and the output of the isolation control module and the voltage regulator module are connected in series between the two outputs of the switching power supply. When a normal operation signal is input, the isolation control module, together with the normal control module, controls the MOSFET to remain on. The isolation control module also controls the MOSFET to turn off when a sleep signal is input. Because the first power supply output voltage of the start control module in this scheme is less than the output voltage of the switching power supply, and the regulated voltage of the voltage regulator module is greater than the first power supply output voltage of the start control module but less than the output DC voltage of the switching power supply, the switch of the start / stop circuit with automatic sleep function of the high-voltage lithium battery pack does not need to bear the full high voltage of the lithium battery pack, but only needs to bear the safe low voltage below 36V. Therefore, this solves the problem that the switch of the start / stop circuit with automatic sleep function of the high-voltage lithium battery pack must bear high voltage, which makes the selection of components complicated, difficult, and uncommon, and reduces the safety performance of the lithium battery pack operation. The technical solution provided by the embodiments of the present invention can provide a universal, low-power, economical, miniaturizable and safe start / stop / automatic sleep circuit and device for any high-voltage lithium battery pack.

[0036] Figure 2 This is a schematic diagram of another battery pack safety start-stop and automatic sleep circuit provided according to an embodiment of the present invention. This embodiment further optimizes the aforementioned embodiments and can be combined with various optional solutions in one or more of the above embodiments. (Reference) Figure 2 Optionally, the start control module 120 includes a first diode D2, a first switch S1, and first power supplies BT1 and BT2.

[0037] The cathode of the first diode D2 is connected to the gate of the MOSFET Q1, the anode of the first diode D2 is connected to the first terminal of the first switch S1, and the second terminal of the first switch S1 is connected to the first power supplies BT1 and BT2.

[0038] In this embodiment, the first power source can be a button cell battery. A button cell battery, also known as a coin cell battery, is a battery that is shaped like a small button. Generally, it has a larger diameter and a thinner thickness. Common button cell batteries are divided into rechargeable and non-rechargeable types. Rechargeable ones include 3.6V rechargeable lithium-ion button cells (LIR series) and 3V rechargeable lithium-ion button cells (ML or VL series). Non-rechargeable ones include 3V lithium manganese button cells (CR series) and 1.5V alkaline zinc manganese button cells (LR and SR series). The button cell battery used in this embodiment is model CR2032 with a nominal voltage of 3V.

[0039] Specifically, when the first switch S1 is pressed, a 6V DC voltage is output from two CR2032 button batteries connected in series. This voltage is applied to the gate of the high-voltage MOSFET Q1 through the gate resistor R1, causing Q1 to conduct. This, in turn, opens the input circuit of the DC switching power supply connected in series with Q1, starting the power supply. After a delay and stabilization, the power supply outputs a low-voltage DC voltage, activating the Battery Management System (BMS).

[0040] Optionally, the first switch includes a self-resetting normally open manual switch.

[0041] Among them, the self-resetting normally open manual switch is a switch with an automatic reset function, used to control the conduction of the high-voltage MOSFET Q1; the first control circuit (called the initial start-up circuit) is composed of a button battery, the self-resetting normally open manual switch and the first diode D2 connected in series, which is used to complete the initial start-up of the battery management system (BMS).

[0042] Optionally, the voltage regulation of the voltage regulator module 150 is greater than the output voltage of the first power supply.

[0043] The function of the voltage regulator module, whose regulated voltage is greater than the output voltage of the first power supply, is to prevent the first diode D2 from conducting, thereby preventing the first power supplies BT1 and BT2 from continuing to consume electrical energy. At this time, even if the self-resetting normally open manual switch is released, the high-voltage MOSFET Q1 will still continue to conduct.

[0044] Optionally, the output voltage of the switching power supply is greater than the output voltage of the first power supply.

[0045] Among them, the switching power supply is a DC switching power supply with a DC output voltage of 10V-36V. The DC switching power supply converts the high-voltage DC power from the high-voltage lithium battery into low-voltage DC power to provide power to the battery management system (BMS) and start the operation of the battery management system (BMS).

[0046] Optionally, the normal control module 130 includes a second diode D1 and a second switch S2. The negative terminal of the second diode D1 is connected to the gate of the high-voltage MOSFET Q1, and the positive terminal of the second diode D1 is connected to the first terminal of the second switch S2. The second terminal of the second switch S2 is connected to the voltage regulator module 150.

[0047] The function of the second diode D1 is to prevent the current from the button battery from flowing back into the normal control circuit.

[0048] Optionally, the second switch S2 includes a self-resetting normally closed manual switch.

[0049] Among them, the self-resetting normally closed manual switch is a switch with an automatic reset function, used to control the conduction of the high-voltage MOSFET Q1; the self-resetting normally closed manual switch and the second diode D1 are connected in series to form a second control circuit (called the normal control circuit), which is used to continue the work of the initial start-up circuit, prevent the power consumption of the button battery, ensure that the button battery has an almost infinite life cycle, and at the same time provide the manual stop function of the battery management system (BMS).

[0050] Optionally, the voltage regulator module 150 includes a Zener diode D3, the negative terminal of which is connected to the second terminal of the second switch S2, and the positive terminal of which is connected to the negative output terminal of the switching power supply.

[0051] The Zener diode can effectively prevent voltage fluctuations caused by changes in the current at the gate of the high-voltage MOSFET Q1 from affecting the circuit, thus maintaining a constant gate voltage at the control terminal of the high-voltage MOSFET Q1. In this embodiment of the invention, the Zener diode output voltage is 8.2V.

[0052] Optionally, the isolation control module 140 includes an optocoupler U1, the input of which is connected to the battery management system; one end of the output of the optocoupler U1 is connected to the positive output of the switching power supply, and the other end of the output of the optocoupler is connected to the voltage regulator module 150.

[0053] The optocoupler, also known as an optocoupler, effectively isolates the control circuit from the switch in a switching circuit. A third control loop (optocoupler isolation loop) is formed by optocoupler U1, optocoupler input resistor R3, optocoupler output resistor R2, and Zener diode D3. This loop converts the program sleep signal from the battery management system (BMS) into an automatic circuit-breaking function. The input of this loop receives the BMS program sleep signal through the optocoupler input resistor R3, while its output is connected in series with the second control loop (normal control loop) through the optocoupler output resistor R2. The Zener diode D3 is connected in parallel with the optocoupler output resistor R2. The optocoupler isolation loop is nested in series with the normal control loop, which in turn is connected in parallel with the initial startup loop. The gate resistor R1 acts on the high-voltage MOSFET Q1, controlling the switching on and off of Q1.

[0054] Specifically, when the Battery Management System (BMS) is set to sleep mode, an output current is generated by the input resistor R3 of the optocoupler. After optocoupler U1 provides optocoupler isolation, the output terminal of the optocoupler, through the output resistor R2 and the Zener diode D3, generates a stable 8.2V control voltage. This voltage is then applied to the gate of the high-voltage MOSFET Q1 via a resettable normally closed manual switch and the second diode D1. After the optocoupler U1 generates a stable 8.2V control voltage through the Zener diode D3, the first diode D2 does not conduct because its cathode potential (8.2V) is higher than its anode potential (6V), thus preventing the button cell battery from continuing to consume power. At this time, even if the resettable switch S1 is released, the high-voltage MOSFET Q1 will continue to conduct.

[0055] Optionally, the gate of the high-voltage MOSFET Q1 is connected to a gate resistor R1.

[0056] The working principle of another battery pack safety start / stop and automatic sleep circuit provided in this embodiment of the invention is as follows: When the self-resetting normally open manual switch S1 is pressed, a certain DC voltage output from two CR2032 button batteries connected in series, for example, the output DC voltage is 6V, is applied to the gate of the high-voltage MOSFET Q1 through the gate resistor R1, causing the high-voltage MOSFET Q1 to conduct, thereby turning on the input circuit of the DC switching power supply connected in series with the high-voltage MOSFET Q1, and starting the switching power supply. After a delay and stabilization, the switching power supply outputs low-voltage DC power, starting the battery management system (BMS); after the battery management system (BMS) successfully self-tests, it sets the BMS sleep signal (active low). The high-level signal is converted into input current by resistor R3. After optocoupler U1 provides optocoupler isolation, the output circuit generates current, which, through optocoupler output resistor R2 and Zener diode D3, produces a stable 8.2V control voltage (which can be set as needed). This voltage is applied to the gate of high-voltage MOSFET Q1 via resettable normally closed manual switch S2 and second diode D1. After U1 generates a stable 8.2V control voltage through Zener diode D3, the first diode D2 does not conduct because its cathode potential (8.2V) is higher than its anode potential (6V), thus preventing the button battery from continuing to consume power. At this time, even if the resettable normally open manual switch S1 is released, high-voltage MOSFET Q1 will continue to conduct.

[0057] During normal system operation (when the self-resetting normally open manual switch S1 has self-reset to the open state), when the Battery Management System (BMS) program detects a system sleep condition, it will reset the BMS sleep signal (outputting a low level), thereby reducing the output current of optocoupler U1 to 0. At this time, after the gate of the high-voltage MOSFET discharges through the gate resistor R1, the gate voltage drops to 0, the high-voltage MOSFET Q1 is turned off, thus disconnecting the input of the switching power supply. The Battery Management System (BMS) loses power, and the system achieves program shutdown.

[0058] At any time during normal system operation (when the self-resetting normally open manual switch S1 has self-reset to the open state, and the self-resetting normally closed manual switch S2 is also in the normally closed state), manually pressing the self-resetting normally closed manual switch S2 disconnects the normal control module 130, the gate signal of the high-voltage MOSFET Q1 disappears, and the high-voltage MOSFET Q1 is also turned off, the input circuit of the switching power supply is disconnected, its output voltage is 0, the battery management system (BMS) is powered off, and the system achieves manual shutdown.

[0059] The technical solution of this invention includes a startup control module comprising a first diode whose negative terminal is connected to the gate of a MOSFET, the positive terminal of the first diode connected to the first terminal of a first switch, and the second terminal of the first switch connected to a first power supply; the first switch being a self-resetting normally open manual switch; a normal operation control module comprising a second diode and a second switch, the negative terminal of the second diode connected to the gate of the MOSFET, the positive terminal of the second diode connected to the first terminal of the second switch, and the second terminal of the second switch connected to a voltage regulator module; the second switch being a self-resetting normally closed manual switch; a voltage regulator module comprising a Zener diode, the negative terminal of which is connected to the second terminal of the second switch, and the positive terminal of which is connected to the negative output terminal of the switching power supply; an isolation control module comprising an optocoupler, the input of which is connected to a battery management system; one end of the output of the optocoupler connected to the positive output terminal of the switching power supply, and the other end of the output of the optocoupler connected to the voltage regulator module; and a gate resistor connected to the gate of the MOSFET. The present invention addresses the problem that the start / stop circuit for high-voltage lithium battery packs with automatic sleep function requires switches to withstand high voltage, making component selection complex, difficult, and uncommon, and reducing the safety performance of lithium battery pack operation. The technical solution provided by the embodiments of the present invention can provide a universal, low-power, economical, miniaturizable, and safe start / stop / automatic sleep circuit and device for any high-voltage lithium battery pack.

[0060] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0061] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A battery pack safety start-stop and automatic sleep circuit, characterized in that, MOSFET, startup control module, normal control module, isolation control module, voltage regulator module; The MOSFET is connected between an output terminal of the battery pack and an input terminal of the switching power supply, which is used to supply power to the battery management system. The startup control module includes a first startup switch, and the startup control module is used to control the MOSFET to turn on according to the action of the first startup switch. The normal control module is connected to the gate of the MOSFET and the voltage regulator module. The input terminal of the isolation control module is used to input the control signal of the battery management system. The output terminal of the isolation control module and the voltage regulator module are connected in series between the two output terminals of the switching power supply. When a normal operation signal is input to the input terminal, the isolation control module, together with the normal control module, controls the MOSFET to remain on. The isolation control module is also used to control the MOSFET to turn off when a sleep signal is input to the input terminal, together with the normal control module. The startup control module includes a first diode, a first switch, and a first power supply; The cathode of the first diode is connected to the gate of the MOS transistor, the anode of the first diode is connected to the first terminal of the first switch, and the second terminal of the first switch is connected to the first power supply. The first power source is a button cell battery, and the switching power supply is a DC switching power supply. The DC switching power supply converts the high-voltage DC power from the high-voltage lithium battery into low-voltage DC power to provide power to the battery management system and start the battery management system.

2. The circuit according to claim 1, characterized in that, The first switch includes a self-resetting normally open manual switch.

3. The circuit according to claim 1, characterized in that, The voltage regulated by the voltage regulator module is greater than the output voltage of the first power supply.

4. The circuit according to any one of claims 1-3, characterized in that, The output voltage of the switching power supply is greater than the output voltage of the first power supply.

5. The circuit according to claim 1, characterized in that, The normal control module includes a second diode and a second switch. The negative terminal of the second diode is connected to the gate of the MOSFET, the positive terminal of the second diode is connected to the first terminal of the second switch, and the second terminal of the second switch is connected to the voltage regulator module.

6. The circuit according to claim 5, characterized in that, The second switch includes a self-resetting normally closed manual switch.

7. The circuit according to claim 5, characterized in that, The voltage regulator module includes a Zener diode, the negative terminal of which is connected to the second terminal of the second switch, and the positive terminal of which is connected to the negative output terminal of the switching power supply.

8. The circuit according to claim 1, characterized in that, The isolation control module includes an optocoupler, the input of which is connected to the battery management system; one end of the output of the optocoupler is connected to the positive output of the switching power supply, and the other end of the output of the optocoupler is connected to the voltage regulator module.

9. The circuit according to claim 1, characterized in that, The gate of the MOS transistor is connected to a gate resistor.

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