High-voltage sampling circuit and battery management system

Abstract

A high-voltage sampling circuit and a battery management system. The high-voltage sampling circuit (20) comprises a resistor voltage division unit (202), a switch unit (203) and a voltage sampling unit (204). The resistor voltage division unit (202) is configured to perform voltage division on bus voltages at two ends of a high-voltage bus (201) to generate a first voltage signal; and the voltage sampling unit (204) comprises an energy storage component (2041) and an isolation component (2042), and is configured to store energy in the energy storage component (2041) by means of the first voltage signal when the switch unit (203) in a first state, and convert the energy stored in the energy storage component (2041) into a second voltage signal when the switch unit (203) is in a second state, and output a third voltage signal by means of the isolation component (2042) from the second voltage signal.

Description

High-voltage sampling circuit and battery management system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure is based on the Chinese patent application with application number 202323089415.4, application date November 15, 2023, and invention name “High-voltage sampling circuit and battery management system”, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this disclosure as a reference. Technical Field

[0003] The present disclosure relates to the technical field of high-voltage sampling, and in particular to a high-voltage sampling circuit and a battery management system. Background Art

[0004] New energy batteries are being used more and more widely in life and industry. For example, new energy vehicles equipped with batteries have been widely used. In addition, batteries are also being increasingly used in energy storage fields.

[0005] To ensure the safe operation of electric vehicles, the battery management system (BMS) in electric vehicles needs to monitor various parameters of the electric vehicle's power battery, such as temperature, voltage, and current. Among them, the power battery voltage is a very important parameter. The BMS needs to sample and detect the high voltage between the positive and negative busbars of the power battery through a high-voltage sampling circuit and take various actions or adjust parameters in a timely manner based on the current busbar voltage changes.

[0006] In related technologies, high-voltage sampling circuits primarily convert the voltage into a low-voltage signal through a voltage-dividing resistor connected in series between the positive and negative busbars. This signal is then isolated and calculated using a sampling chip and an isolation communication chip before being transmitted to a microcontroller unit (MCU). However, this high-voltage sampling circuit is expensive and complex, reducing circuit reliability.

[0007] Summary of the Invention

[0008] The present disclosure mainly provides a high-voltage sampling circuit and a battery management system, which performs high-voltage sampling by controlling the energy storage and conversion in the energy storage component through a switch unit, thereby reducing circuit cost and circuit complexity, thereby improving the reliability of the high-voltage sampling circuit.

[0009] The technical solution of the present disclosure is achieved as follows:

[0010] In a first aspect, an embodiment of the present disclosure provides a high-voltage sampling circuit, which includes a resistor divider unit, a switch unit, and a voltage sampling unit, wherein two ends of the resistor divider unit are respectively connected to two ends of a high-voltage bus, and an output end of the resistor divider unit is connected to the voltage sampling unit through the switch unit, wherein:

[0011] a resistor voltage dividing unit configured to divide the bus voltage at both ends of the high-voltage bus to generate a first voltage signal;

[0012] The voltage sampling unit includes an energy storage component and an isolation component, and is configured to store energy in the energy storage component through a first voltage signal when the switch unit is in a first state; and when the switch unit is in a second state, convert the energy stored in the energy storage component into a second voltage signal, and output the second voltage signal as a third voltage signal through the isolation component.

[0013] Through the above technical means, when the switch unit is in different states, the voltage at both ends of the high-voltage bus is sampled by controlling the energy storage and conversion of the energy storage component in the voltage sampling unit, which not only reduces the circuit cost, but also reduces the circuit complexity, thereby improving the reliability of the high-voltage sampling circuit.

[0014] In some embodiments, the resistor voltage divider unit includes a plurality of voltage divider resistors, wherein:

[0015] One of the multiple voltage-dividing resistors is used as a sampling resistor, and output terminals are drawn from both ends of the sampling resistor and connected to the switch unit.

[0016] By using the above technical means, the two ends of the sampling resistor in the multiple voltage-dividing resistors are connected to the switch unit to divide the high voltage at both ends of the high-voltage bus, thereby simplifying the circuit of the high-voltage sampling circuit and reducing the cost.

[0017] In some embodiments, the plurality of voltage-dividing resistors include a first resistor, a second resistor, and a third resistor, and the second resistor serves as a sampling resistor; wherein:

[0018] A first end of the first resistor is connected to the positive terminal of the high-voltage bus, and a second end of the first resistor is connected to the first end of the second resistor and the first input terminal of the switch unit respectively;

[0019] The first end of the third resistor is connected to the second end of the second resistor and the second input end of the switch unit respectively, and the second end of the third resistor is connected to the negative terminal of the high-voltage bus.

[0020] Through the above technical means, the high voltage at both ends of the high-voltage bus is divided by multiple voltage-dividing resistors, and the first voltage signal is output from both ends of the second resistor, which simplifies the circuit of the high-voltage sampling circuit and reduces the cost.

[0021] In some embodiments, the switch unit includes a first set of switches and a second set of switches, wherein:

[0022] The switch unit is in a first state, comprising: a first set of switches being in an on state and a second set of switches being in an off state;

[0023] The switch unit is in a second state, including: the first group of switches is in an off state and the second group of switches is in an on state.

[0024] Through the above technical means, the switch unit can be in different states, thereby controlling the energy storage and conversion of the energy storage components in the voltage sampling unit, and sampling the voltage at both ends of the high-voltage bus. This not only reduces the circuit cost, but also simplifies the circuit and improves the reliability of the high-voltage sampling circuit.

[0025] In some embodiments, the first set of switches includes a first switch and a second switch, and the second set of switches includes a third switch and a fourth switch; wherein:

[0026] The first end of the first switch is connected to the second end of the first resistor and the first end of the second resistor as the first input end of the switch unit, the second end of the first switch is connected to the first end of the energy storage component and the first end of the third switch, and the second end of the third switch is connected to the input end of the isolation component as the first output end of the switch unit;

[0027] The first end of the second switch is connected to the second end of the second resistor and the first end of the third resistor as the second input end of the switch unit, the second end of the second switch is connected to the second end of the energy storage component and the first end of the fourth switch, and the second end of the fourth switch is grounded as the second output end of the switch unit.

[0028] Through the above-mentioned technical means, the switch unit includes a first switch, a second switch, a third switch and a fourth switch. By controlling the opening or closing of each switch in the switch unit, the energy storage and conversion of the energy storage component in the voltage sampling unit are controlled, and the voltage at both ends of the high-voltage bus is sampled. This not only reduces the circuit cost, but also simplifies the circuit and improves the reliability of the high-voltage sampling circuit.

[0029] In some embodiments, the energy storage component includes a first capacitor, wherein:

[0030] The first end of the first capacitor is connected to the connection line between the first switch and the third switch as the first end of the energy storage component, and the second end of the first capacitor is connected to the connection line between the second switch and the fourth switch as the second end of the energy storage component.

[0031] Through the above technical means, the energy storage component can include a first capacitor for storing, converting and releasing energy, thereby reducing the cost and complexity of the circuit and improving the reliability of the circuit.

[0032] In some embodiments, the first capacitor is used to store energy in the first capacitor according to the sampled voltage across the second resistor when the first switch and the second switch are in the on state and the third switch and the fourth switch are in the off state; and to convert the energy stored in the first capacitor into a second voltage signal and transmit the second voltage signal to the isolation component when the first switch and the second switch are in the off state and the third switch and the fourth switch are in the on state.

[0033] Through the above technical means, the energy is stored, converted and released by the first capacitor, and the voltage across the second resistor is transmitted to the isolation component and the devices subsequently connected to the isolation component, thereby reducing the cost and complexity of the circuit and improving the reliability of the circuit.

[0034] In some embodiments, the isolation component comprises a voltage follower, wherein:

[0035] The positive input terminal of the voltage follower is connected to the first output terminal of the switch unit, and the negative input terminal of the voltage follower is connected to the output terminal of the voltage follower, for outputting a third voltage signal.

[0036] Through the above technical means, the high-voltage side and the low-voltage side of the circuit are isolated by the voltage follower, preventing high voltage or dangerous signals from being transmitted to the low-voltage side, thereby improving the safety of the circuit.

[0037] In some embodiments, the isolation component includes a voltage follower and a fourth resistor, wherein:

[0038] The positive input terminal of the voltage follower is connected to the first output terminal of the switch unit, the negative input terminal of the voltage follower is connected to the first terminal of the fourth resistor, and the second terminal of the fourth resistor is connected to the output terminal of the voltage follower for outputting a third voltage signal.

[0039] Through the above technical means, the high-voltage side and the low-voltage side of the circuit are isolated through the voltage follower and the fourth resistor, preventing high voltage or dangerous signals from being transmitted to the low-voltage side, thereby improving the safety of the circuit.

[0040] In some embodiments, the resistor voltage dividing unit further includes a fifth switch connected between the plurality of voltage dividing resistors, wherein:

[0041] The fifth switch is used to control the on / off of the resistor voltage divider unit to control the working state of the high-voltage sampling circuit.

[0042] Through the above-mentioned technical means, the embodiment of the present disclosure provides a high-voltage sampling circuit, which controls the working state of the high-voltage sampling circuit by opening and closing the fifth switch. The power consumption and cost of the fifth switch are low, and the circuit is simple, which not only reduces the circuit cost, but also simplifies the circuit and improves the reliability of the high-voltage sampling circuit.

[0043] In a second aspect, an embodiment of the present disclosure provides a battery management system, the battery management system comprising a high-voltage sampling circuit and a controller as described in any one of the first aspects, wherein:

[0044] The output end of the high-voltage sampling circuit is connected to the controller and is used to provide the third voltage signal output by the high-voltage sampling circuit to the controller.

[0045] Through the above technical means, the sampling circuit is simple and the controller directly collects the sampling voltage, which can effectively reduce the cost of the sampling circuit while simplifying the sampling signal transmission and improving reliability.

[0046] In some embodiments, the controller is further configured to send a control command to a switch in the switch unit, where the control command is configured to control the switch in the switch unit to be in an on state or an off state.

[0047] Through the above technical means, the controller controls the opening and closing of the switch unit, thereby ensuring the normal operation of the high-voltage sampling circuit.

[0048] The present disclosure provides a high-voltage sampling circuit and a battery management system. When the switch unit is in a first state, the energy storage component stores energy by dividing the bus voltage at both ends of the high-voltage bus to generate a first voltage signal. When the switch unit is in a second state, the energy stored in the energy storage component is converted into a second voltage signal, and then a third voltage signal is output through the isolation component as the result of high-voltage sampling. In this way, compared with the related art, there is no need to use a dedicated sampling chip. Isolated high-voltage sampling can be achieved only through the energy storage component and the switch unit, thereby simplifying the circuit and reducing the circuit complexity. It can also simplify the transmission of the sampling signal while effectively reducing the circuit cost, thereby improving the reliability of the high-voltage sampling circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] FIG1 is a schematic diagram of the structure of a high-voltage sampling circuit;

[0050] FIG2 is a first schematic diagram of the structure of a high-voltage sampling circuit provided by an embodiment of the present disclosure;

[0051] FIG3 is a second structural diagram of a high-voltage sampling circuit provided by an embodiment of the present disclosure;

[0052] FIG4 is a third structural diagram of a high-voltage sampling circuit provided by an embodiment of the present disclosure;

[0053] FIG5 is a fourth structural diagram of a high-voltage sampling circuit provided by an embodiment of the present disclosure;

[0054] FIG6 is a fifth structural diagram of a high-voltage sampling circuit provided by an embodiment of the present disclosure;

[0055] FIG7 is a sixth structural diagram of a high-voltage sampling circuit provided by an embodiment of the present disclosure;

[0056] FIG8 is a seventh structural diagram of a high-voltage sampling circuit provided by an embodiment of the present disclosure;

[0057] FIG9 is a first schematic diagram of the structure of a battery management system provided by an embodiment of the present disclosure;

[0058] FIG10 is a second schematic diagram of the structure of a battery management system provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0059] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure is described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference only and are not intended to limit the embodiments of the present disclosure.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art in the art of the present disclosure. The terms used herein are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0061] In the following description, reference is made to “some embodiments”, which describes a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0062] It should also be pointed out that the terms "first\second\third" involved in the embodiments of the present disclosure are only used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present disclosure described herein can be implemented in an order other than that illustrated or described herein.

[0063] Currently, new energy batteries are increasingly being used in everyday life and industry. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in a variety of fields such as aerospace. As the application of power batteries continues to expand, market demand is also growing.

[0064] In the embodiments of the present disclosure, the battery may be a battery cell (sometimes also referred to as a battery cell), or a battery module or battery pack comprising a plurality of battery cells. A battery cell refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, and can be used to make a battery module or battery pack, thereby being used to supply power to electrical devices. A battery cell may be a secondary battery, which refers to a battery cell that can be activated by charging the active material after the battery cell is discharged and can continue to be used. The battery cell may be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present disclosure are not limited thereto.

[0065] Electric vehicles rely on power batteries to provide energy and drive, with an operating voltage platform typically ranging from 200Vdc to 750Vdc. The power battery pack and the DC portion of its associated electrical assembly together form the electric vehicle's high-voltage DC bus. During operation, the high-voltage DC bus requires real-time monitoring, with the vehicle's controller performing calculations and performing logical protection decisions based on the monitored voltage values.

[0066] Figure 1 is a schematic diagram of the structure of a high-voltage sampling circuit. As shown in Figure 1, the high-voltage sampling circuit 10 is used to sample a power battery 101, which can be composed of multiple connected battery modules. Multiple voltage-dividing resistors are connected in series between the positive terminal 1021 and the negative terminal 1022 of the power battery 101. For example, the multiple voltage-dividing resistors may include a first voltage-dividing resistor 103 and a second voltage-dividing resistor 104. One of the voltage-dividing resistors, illustratively, the second voltage-dividing resistor 104, is set as the sampling point. In this way, the high-voltage analog signal between the positive terminal 1021 and the negative terminal 1022 of the power battery 101 is converted into a low-voltage analog signal by the second voltage-dividing resistor 104. This low-voltage analog signal is then input into the sampling chip 106 for further processing. For example, the sampling chip 106 converts the low-voltage analog signal into a digital analog signal and sends it to the isolation communication chip 107 for isolation. Finally, the isolated communication signal is transmitted to the microcontroller unit 108. Among them, the isolation communication chip 107 is a safety device used to ensure the isolation between the high-voltage circuit and the low-voltage circuit, that is, the safety of the voltage signal transmission between the power battery 101 side and the micro control unit 108 side, to prevent the high-voltage signal from damaging the circuit on the micro control unit 108 side.

[0067] It should be noted that the optical MOS switch 105 can be an electronic switch used to control the conduction or disconnection of the path between multiple voltage-dividing resistors and the power battery 101. When the high-voltage sampling circuit 10 needs to sleep or an abnormality occurs, the microcontroller unit 108 can control the optical MOS switch 105 to be disconnected to prevent leakage current from entering the sampling chip 106, the isolation communication chip 107, etc., thereby avoiding damage to the high-voltage sampling circuit 10.

[0068] In addition, an isolated power supply 109 may be further provided in the high-voltage sampling circuit 10 to supply power to the sampling chip 106 .

[0069] Although the high-voltage sampling circuit 10 described above can be used in related technologies to sample the high voltage of the power battery 101 and obtain a low-voltage digital signal, in this high-voltage sampling circuit 10, the low-voltage analog signal needs to be converted and transmitted through the sampling chip 106 and the isolated communication chip 107, resulting in a complex transmission process and low circuit reliability. Moreover, in this high-voltage sampling circuit 10, not only a dedicated sampling chip 106 is required, but also an isolated power supply 109 to power the sampling chip 106, as well as an isolated communication chip 107, which makes the circuit structure of the high-voltage sampling circuit 10 complex and the cost high.

[0070] Based on the above technical problems, the embodiments of the present disclosure provide a high-voltage sampling circuit and a battery management system. When the switch unit is in different states, the voltage at both ends of the high-voltage bus is sampled by controlling the energy storage and conversion of the energy storage component in the voltage sampling unit. This not only reduces the circuit cost, but also simplifies the circuit and improves the reliability of the high-voltage sampling circuit.

[0071] The present disclosure is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0072] In one embodiment of the present disclosure, FIG2 is a schematic diagram illustrating the first structure of a high-voltage sampling circuit provided in an embodiment of the present disclosure. As shown in FIG2 , the high-voltage sampling circuit 20 may include a resistor divider unit 202, a switch unit 203, and a voltage sampling unit 204. The two ends of the resistor divider unit 202 are respectively connected to the two ends of a high-voltage bus 201, and the output end of the resistor divider unit 202 is connected to the voltage sampling unit 204 via the switch unit 203.

[0073] The high-voltage bus 201 may include a positive terminal 2011 and a negative terminal 2012, and is composed of the DC portion of the power battery pack and related electrical assemblies within the BMS. The electrical assemblies may include an on-board charger (OBC) and a vehicle control unit (VCU). It should be noted that the positive terminal 2011 of the high-voltage bus may also be referred to as HV+, and the negative terminal 2012 of the high-voltage bus may also be referred to as HV-.

[0074] It should also be noted that the switch unit 203 may include multiple switches, and each switch may be in an open or closed state.

[0075] The resistor voltage dividing unit 202 is configured to divide the bus voltage at both ends of the high-voltage bus 201 to generate a first voltage signal.

[0076] The resistor divider unit 202 may include multiple resistors connected in series. In the embodiment of the present disclosure, the voltage at both ends of the high-voltage bus 201 may be divided by the resistor divider unit 202, and a resistor in the resistor divider unit 202 may be selected as a sampling resistor. The two ends of the sampling resistor may serve as the output ends of the resistor divider unit 202 and be connected to the voltage sampling unit 204 through the switch unit 203.

[0077] It can be understood that the first voltage signal is a low voltage signal outputted through a sampling resistor, that is, the output end of the resistor divider unit 202 , after the resistor divider unit 202 divides the high voltage at both ends of the high-voltage bus 201 .

[0078] The voltage sampling unit 204 includes an energy storage component 2041 and an isolation component 2042, and is configured to store energy in the energy storage component 2041 through a first voltage signal when the switch unit 203 is in a first state; and when the switch unit 203 is in a second state, convert the energy stored in the energy storage component 2041 into a second voltage signal, and output the second voltage signal as a third voltage signal through the isolation component 2042.

[0079] The energy storage component 2041 may be a capacitor, which is used to quickly convert the first voltage signal into stored energy and enable the voltages at both ends of the energy storage component 2041 and the output end of the resistive voltage divider unit 202 to be equal.

[0080] The isolation component 2042 can be a magnetic coupling isolator, an optical coupling isolator, a voltage follower or other device, which is used to isolate high voltage and low voltage.

[0081] In the embodiment of the present disclosure, the state of all switches of the switch unit 203 at a certain moment being open or closed can be referred to as the state of the switch unit 203. It can be understood that in order to separate the high-voltage side from the low-voltage side of the high-voltage sampling circuit 20, that is, to separate the high-voltage bus 201 from the devices subsequently connected to the voltage sampling unit 204, not only the isolation component 2042 is required, but also the switch unit 203 needs to be adjusted to different states to disconnect or connect the circuit between the voltage sampling unit 204 and the high-voltage bus 201. Exemplarily, it can be preset that when the switch unit 203 is in the first state, the circuit between the voltage sampling unit 204 and the high-voltage bus 201 is connected, and the energy storage component is disconnected from the subsequently connected circuit, so that the high voltage between the high-voltage bus 201 is divided by the resistance divider unit 202, and a first voltage signal is output to the energy storage component 2041 of the voltage sampling unit 204 for storage; or, when the switch unit 203 is in the second state, the voltage sampling unit 204 and the high-voltage bus 201 are disconnected, and the circuit between the energy storage component and the subsequently connected circuit is connected, so that the energy stored in the energy storage component 2041 is released to the isolation component 2042 in the form of a second voltage signal through the switch unit 203, and then converted by the isolation component 2042, and a third voltage signal is output to the subsequently connected device for analysis and processing.

[0082] It can be understood that in order to ensure the accuracy of the high-voltage sampling result, the voltage value of the first voltage signal, the voltage value of the second voltage signal, and the voltage value of the third voltage signal should be equal.

[0083] An embodiment of the present disclosure provides a high-voltage sampling circuit that samples the voltage at both ends of a high-voltage bus by controlling the energy storage and conversion of an energy storage component in a voltage sampling unit when the switching unit is in different states. This not only reduces circuit cost, but also simplifies the circuit and improves the reliability of the high-voltage sampling circuit.

[0084] In another embodiment of the present disclosure, based on the high-voltage sampling circuit 20 described in the above embodiment, Figure 3 is a second schematic diagram of the structure of a high-voltage sampling circuit provided by the present disclosure. As shown in Figure 3, the resistor divider unit 202 may include multiple voltage divider resistors.

[0085] Wherein, one of the multiple voltage-dividing resistors is used as a sampling resistor, and output terminals are drawn out from both ends of the sampling resistor and connected to the switch unit.

[0086] As in the aforementioned embodiment, the resistor divider unit 202 may include multiple resistors connected in series. Based on Ohm's law and the relationship between series resistances, by selecting an appropriate resistance ratio, the input high voltage can be divided into the required low voltage, i.e., the first voltage signal, and output through both ends of the sampling resistor in the resistor divider unit 202.

[0087] It can be understood that the multiple voltage-dividing resistors in the resistor voltage-dividing unit 202 can be appropriately selected according to the voltage range across the high-voltage bus 201 , wherein the sampling resistor can be determined according to the voltage value of the first voltage signal to be output.

[0088] In some embodiments, referring to FIG. 3 , the plurality of voltage-dividing resistors may include a first resistor 2021 , a second resistor 2022 , and a third resistor 2023 , with the second resistor 2022 serving as a sampling resistor.

[0089] It should be noted that FIG3 of the embodiment of the present disclosure takes the resistor divider unit 202 including three divider resistors as an example for illustration. In actual use, the number of divider resistors in the resistor divider unit 202 can be adjusted according to specific circumstances or needs.

[0090] Among them, the first end of the first resistor 2021 is connected to the positive terminal 2011 of the high-voltage bus, and the second end of the first resistor 2021 is respectively connected to the first end of the second resistor 2022 and the first input terminal of the switch unit 203; the first end of the third resistor 2023 is respectively connected to the second end of the second resistor 2022 and the second input terminal of the switch unit 203, and the second end of the third resistor 2023 is connected to the negative terminal 2012 of the high-voltage bus.

[0091] In the embodiment of the present disclosure, the second resistor 2022 can be used as a sampling resistor, and the output terminals at both ends of the second resistor 2022 are respectively connected to the first input end of the switch unit 203 and the second input end of the switch unit 203. In this way, the voltage across the second resistor 2022 is used as the first voltage signal, and when the switch unit is in the first state, it is input to the energy storage component 2041 through the switch unit 203 for storage.

[0092] It should be noted that in the disclosed embodiment, the resistance of the first resistor 2021 can be 4M, the resistance of the second resistor 2022 can be 80K, and the resistance of the third resistor 2023 can be 4M. Depending on the specific usage scenario, the resistance of the first resistor 2021, the resistance of the second resistor 2022, and the resistance of the third resistor 2023 can be appropriately changed. In addition, when the resistance values ​​of multiple voltage divider resistors change, other resistors can also be used as sampling resistors.

[0093] The embodiment of the present disclosure provides a high-voltage sampling circuit, which divides the high voltage at both ends of a high-voltage bus through multiple voltage-dividing resistors and outputs a first voltage signal from both ends of the sampling resistors, thereby simplifying the circuit of the high-voltage sampling circuit and reducing costs.

[0094] In another embodiment of the present disclosure, based on the high-voltage sampling circuit 20 described in the above embodiment, FIG4 is a third structural diagram of a high-voltage sampling circuit provided by the present disclosure. As shown in FIG4 , the switch unit 203 may include a first set of switches 2031 and a second set of switches 2032 .

[0095] The switch unit 203 is in a first state, including: the first group of switches 2031 is in an on state and the second group of switches 2032 is in an off state.

[0096] In the embodiment of the present disclosure, taking the second resistor 2022 as a sampling resistor as an example, when the switch unit 203 is in the first state, the first set of switches 2031 is closed, and the second set of switches 2032 is opened, so that the sampling circuit 2032 is connected to the energy storage component 2041, and the first voltage signal outputted from both ends of the second resistor 2022 is inputted into the energy storage component 2041 for storage.

[0097] The switch unit 203 is in the second state, including: the first group of switches 2031 is in the off state and the second group of switches 2032 is in the on state.

[0098] In the embodiment of the present disclosure, when the switch unit 203 is in the second state, the first group of switches 2031 is opened, and the second group of switches 2032 is closed, so that the energy storage component 2041 is connected to the isolation component 2042, and the energy stored in the energy storage component 2041 is converted into a second voltage signal and transmitted to the isolation component 2042.

[0099] In some embodiments, the first switch group 2031 includes a first switch S1 and a second switch S2 , and the second switch group 2032 includes a third switch S3 and a fourth switch S4 .

[0100] The first end of the first switch S1 is connected to the second end of the first resistor 2021 and the first end of the second resistor 2022 as the first input end of the switch unit 203, the second end of the first switch S1 is connected to the first end of the energy storage component 2041 and the first end of the third switch S3, and the second end of the third switch S3 is connected to the input end of the isolation component 2042 as the first output end of the switch unit 203.

[0101] The first end of the second switch S2 is connected to the second end of the second resistor 2022 and the first end of the third resistor 2023 as the second input end of the switch unit 203, respectively. The second end of the second switch S2 is connected to the second end of the energy storage component 2041 and the first end of the fourth switch S4, respectively. The second end of the fourth switch S4 is grounded as the second output end of the switch unit 203.

[0102] It should be noted that the opening and closing of the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 can all be controlled by the MCU in the BMS. The MCU can control the on and off timings of the first and second switches 2031, 2032 according to the capacity of the energy storage component 2041, thereby controlling the energy storage and release times of the energy storage component 2041.

[0103] In the disclosed embodiment, when the switch unit 203 is in the first state, the first switch S1 and the second switch S2 are closed, and the third switch S3 and the fourth switch S4 are open, connecting the sampling resistor, i.e., the second resistor 2022, in parallel with the energy storage component 2041. This ensures that the voltage across the sampling resistor is equal to the voltage across the energy storage component 2041. In this way, the first voltage signal output from the sampling resistor is transmitted to the energy storage component 2041 for storage via the first switch S1 and the second switch S2, respectively. Under the control of the MCU, the switch unit 203 remains in the first state until the energy storage component 2041 is fully charged.

[0104] In the disclosed embodiment, when the switch unit 203 is in the first state, the first switch S1 and the second switch S2 are open, and the third switch S3 and the fourth switch S4 are closed, so that one end of the energy storage component 2041 is grounded and the other end is connected to the isolation component 2042. In this way, the energy stored in the energy storage component 2041 is converted into a second voltage signal, released toward the isolation component 2042, and output after passing through the isolation component 2042. Under the control of the MCU, the switch unit 203 remains in the second state until the energy of the energy storage component 2041 is completely released.

[0105] It can be understood that in the embodiment of the present disclosure, since the voltage value of the first voltage signal is equal to the voltage value across the energy storage component 2041, the voltage value of the second voltage signal output when the energy storage component 2041 releases energy is equal to the voltage value of the first voltage signal.

[0106] It should be noted that the first switch S1 , the second switch S2 , the third switch S3 , and the fourth switch S4 may be knife switches, MOS transistors, or other devices having the function of controlling the circuit to be turned on or off.

[0107] An embodiment of the present disclosure provides a high-voltage sampling circuit, wherein a switch unit includes a first switch, a second switch, a third switch, and a fourth switch. By controlling the opening or closing of each switch in the switch unit, the switch unit is controlled to be in different states, thereby controlling the energy storage and conversion of the energy storage component in the voltage sampling unit, and sampling the voltage at both ends of the high-voltage bus. This not only reduces circuit cost, but also simplifies the circuit and improves the reliability of the high-voltage sampling circuit.

[0108] In another embodiment of the present disclosure, based on the high-voltage sampling circuit 20 described in the above embodiment, Figure 5 is a fourth structural diagram of a high-voltage sampling circuit provided by the present disclosure. As shown in Figure 5 , the energy storage component 2041 can be a first capacitor C1.

[0109] The first end of the first capacitor C1 is connected to the connection line between the first switch S1 and the third switch S3 as the first end of the energy storage component, and the second end of the first capacitor C1 is connected to the connection line between the second switch S2 and the fourth switch S4 as the second end of the energy storage component.

[0110] As shown in FIG5 , when the energy storage component 2041 is the first capacitor C1 , in the embodiment of the present disclosure, the first capacitor C1 is connected in parallel with the second resistor 2022 , and energy is stored in the first capacitor C1 through the first voltage signal output by the second resistor 2022 until the first capacitor C1 is fully charged.

[0111] It should be noted that the energy storage component 2041 may also be composed of multiple capacitors connected in parallel, or multiple capacitors connected in series, or other devices that can achieve the purpose of energy storage, which can be adjusted according to specific usage conditions.

[0112] In the disclosed embodiment, the capacitance value of the first capacitor C1 can be 100nF. The capacitance value of the first capacitor C1 can be adaptively adjusted according to the voltage value of the first voltage signal. However, to ensure the accuracy of the high-voltage sampling circuit, the capacitance value of the first capacitor C1 should be greater than the voltage value of the first voltage signal to avoid overflow of the first voltage signal when the first capacitor C1 stores energy according to the first voltage signal.

[0113] In some embodiments, referring again to FIG. 5 , the first capacitor C1 is configured to store energy in the first capacitor C1 according to the sampled voltage across the second resistor 2022 when the first switch S1 and the second switch S2 are in the on state and the third switch S3 and the fourth switch S4 are in the off state; and to convert the energy stored in the first capacitor C1 into a second voltage signal and transmit the second voltage signal to the isolation component 2042 when the first switch S1 and the second switch S2 are in the off state and the third switch S3 and the fourth switch S4 are in the on state.

[0114] As in the aforementioned embodiment, the second resistor 2022 is a sampling resistor in the resistor divider unit 202. The sampled voltage across the second resistor 2022 is equal to the voltage of the first voltage signal. Thus, when the switch unit is in the first state, that is, when the first switch S1 and the second switch S2 are in the on state and the third switch S3 and the fourth switch S4 are in the off state, the first capacitor C1 is connected in parallel with the second resistor 2022, and the first capacitor C1 is disconnected from the isolation component 2042 and any subsequent devices connected to the isolation component 2042. The second resistor 2022 outputs the first voltage signal to the first capacitor C1, causing the first capacitor C1 to store energy. When the first capacitor C1 is fully charged, the control switch unit is in the second state, that is, the first switch S1 and the second switch S2 are in the disconnected state and the third switch S3 and the fourth switch S4 are in the on state, the first capacitor C1 is disconnected from the second resistor 2022, and one end of the first capacitor C1 is grounded, and the other end of the first capacitor C1 is connected to the isolation component 2042, so that the energy stored in the first capacitor C1 is converted into a second voltage signal and transmitted to the isolation component 2042.

[0115] An embodiment of the present disclosure provides a high-voltage sampling circuit, in which the energy storage component can be a first capacitor. The first capacitor stores, converts and releases energy, and transmits the voltage across the second resistor to the isolation component and devices subsequently connected to the isolation component, thereby reducing the cost and complexity of the circuit and improving the reliability of the circuit.

[0116] In another embodiment of the present disclosure, based on the high-voltage sampling circuit 20 described in the aforementioned embodiment, the isolation component 2042 is mainly used to isolate the high-voltage side of the circuit from the low-voltage side. For example, it can be an isolation communication chip, a magnetic coupling isolator, an optical coupling isolator, a voltage follower, etc.

[0117] Taking the isolation component 2042 as a voltage follower as an example, in a possible implementation, FIG6 is a fifth structural diagram of a high-voltage sampling circuit provided by an embodiment of the present disclosure. As shown in FIG6 , the isolation component 2042 may include a voltage follower 20421 .

[0118] The positive input terminal of the voltage follower 20421 is connected to the first output terminal of the switch unit, and the negative input terminal of the voltage follower 20421 is connected to the output terminal of the voltage follower 20421, for outputting a third voltage signal.

[0119] The voltage follower 20421 can be a device whose output voltage changes with changes in the input voltage. By utilizing the characteristics of high input impedance and low output impedance of the voltage follower 20421, and the fact that the voltage follower 20421 presents a high-resistance state to the upper circuit and a low-resistance state to the lower circuit, the output voltage can be made close to the input voltage amplitude, and the voltage of the previous stage can be output without loss. By setting the voltage follower 20421 between the high-voltage side and the low-voltage side of the high-voltage sampling circuit, the influence caused by the direct connection between the high-voltage side and the low-voltage side of the circuit can be effectively isolated, thereby playing an isolation and buffering role.

[0120] In the embodiment of the present disclosure, when the switch unit is in the second state, the first group of switches 2031 is disconnected and the second group of switches 2032 is turned on. The energy storage component 2041 converts the stored energy into a second voltage signal and transmits the second voltage signal to the voltage follower 20421 through the second group of switches 2032. After the positive input terminal of the voltage follower 20421 receives the second voltage signal, the third voltage signal is output through the output terminal to the subsequent circuit connected to the voltage follower 20421.

[0121] Taking the isolation component 2042 as a voltage follower as an example, in another possible implementation, FIG7 is a sixth schematic diagram of the structure of a high-voltage sampling circuit provided by an embodiment of the present disclosure. As shown in FIG7 , the isolation component 2042 may further include a voltage follower 20421 and a fourth resistor 20422 .

[0122] Among them, the positive input end of the voltage follower 20421 is connected to the first output end of the switching unit, the negative input end of the voltage follower 20421 is connected to the first end of the fourth resistor 20422, and the second end of the fourth resistor 20422 is connected to the output end of the voltage follower 20421 for outputting a third voltage signal.

[0123] It can be understood that in order to improve the output current capability of the voltage follower 20421 or limit the current, a fourth resistor 20422 can be added to the feedback loop of the voltage follower 20421, which can change the output impedance of the voltage follower 20421 to a certain extent and change the current amplification factor.

[0124] It should be noted that the isolation component 2042 may also be composed of other components, such as a magnetic coupling isolator, an optical coupling isolator or a transformer, etc., which are not listed one by one in the embodiment of the present disclosure.

[0125] The embodiments of the present disclosure provide a high-voltage sampling circuit, which isolates the high-voltage side of the circuit from the low-voltage side through an isolation component, preventing high voltage or dangerous signals from being transmitted to the low-voltage side, thereby improving the safety of the circuit.

[0126] In another embodiment of the present disclosure, based on the high-voltage sampling circuit 20 described in the previous embodiment, FIG8 is a seventh schematic diagram of the structure of a high-voltage sampling circuit provided in an embodiment of the present disclosure. As shown in FIG8 , the resistor divider unit 202 may further include a fifth switch 205 connected between the multiple voltage divider resistors.

[0127] The fifth switch 205 is used to control the on / off of the resistor voltage divider unit 202 to control the working state of the high-voltage sampling circuit 20 .

[0128] It should be noted that the operating state of the high-voltage sampling circuit 20 can refer to whether the high-voltage sampling circuit 20 is in a sampling state or a power-off state. When the fifth switch 205 is turned on, the resistor voltage divider unit 202 is turned on, and the high-voltage sampling circuit 20 is in the sampling state. When the fifth switch 205 is turned off, the resistor voltage divider unit 202 is turned off, and the high-voltage sampling circuit 20 is in the power-off state.

[0129] The fifth switch 205 can be a photo MOS switch, a high voltage isolating switch, a field effect transistor or the like, and controls the working state of the high voltage sampling circuit 20 by controlling the on-off between the high voltage bus and the resistor divider unit 202 .

[0130] In the embodiment of the present disclosure, the fifth switch 205 is arranged between the first resistor 2021 and the second resistor 2022. It can be understood that the fifth switch 205 can also be arranged between the first resistor 2021 and the positive terminal 2011 of the high-voltage bus, or at other locations that can control the working state of the high-voltage sampling circuit 20.

[0131] The embodiment of the present disclosure provides a high-voltage sampling circuit, which controls the working state of the high-voltage sampling circuit by opening and closing a fifth switch. The fifth switch has low power consumption and cost, and the circuit is simple, which not only reduces the circuit cost but also simplifies the circuit and improves the reliability of the high-voltage sampling circuit.

[0132] In yet another embodiment of the present disclosure, FIG9 is a structural diagram of a battery management system according to an embodiment of the present disclosure. As shown in FIG9 , the battery management system 30 includes the high-voltage sampling circuit 20 and the controller 301 as described in the above embodiment.

[0133] The output end of the high-voltage sampling circuit 20 is connected to the controller 301 , and is used to provide the third voltage signal output by the high-voltage sampling circuit 20 to the controller 301 .

[0134] The controller 301 may be an MCU or other devices with computing and processing functions, which are not listed here in this disclosure.

[0135] The high-voltage sampling circuit 20 converts the bus voltage at both ends of the high-voltage bus into a third voltage signal through the resistor divider unit and the voltage sampling unit, and outputs it to the controller 301. The controller 301 can determine the bus voltage value at both ends of the high-voltage bus based on the third voltage signal to further determine the operating status of the power battery or the capacity of the power battery.

[0136] The embodiments of the present disclosure provide a battery management system. The high-voltage sampling circuit is simple, and the controller directly collects the sampling voltage, which can effectively reduce the cost of the sampling circuit while simplifying the sampling signal transmission and improving reliability.

[0137] In another embodiment of the present disclosure, based on the aforementioned battery management system 30, the workflow of the battery management system 30 is described below using a specific application scenario in which the resistor divider unit 202 includes a 4M resistor, an 80K resistor, and a 4M resistor, and the first capacitor C1 is 100nF.

[0138] Based on this application scenario, Figure 10 is a second schematic diagram of the structure of a battery management system provided in an embodiment of the present disclosure. As shown in Figure 10, the battery management system 30 may include a high-voltage sampling circuit 20 and a controller 301. The controller 301 is also configured to send control commands to the switches in the switch unit 203, which are used to control the switches in the switch unit 203 to be in the on or off state.

[0139] As shown in FIG. 10 , the high-voltage sampling circuit 20 may include a resistor divider unit 202 , a first set of switches 2031 , a second set of switches 2032 , a first capacitor C1 , a voltage follower 20421 , and a fourth resistor 20422 . Among them, the resistance divider unit 202 includes a first resistor 2021 (for example, a 4M resistor), a second resistor 2022 (for example, an 80K resistor) and a third resistor 2023 (for example, a 4M resistor), where the resistance value can be modified according to the specific scheme, and the second resistor 2022 can be selected as the sampling resistor; and the first resistor 2021, the second resistor 2022 and the third resistor 2023 are connected in series between the positive terminal 2011 and the negative terminal 2012 of the high-voltage bus 201; in addition, the first group of switches 2031 and the second group of switches 2032 constitute a switching unit, which can specifically include a first switch S1, a second switch S2, a third switch S3 and a fourth switch S4; the first capacitor C1 serves as an energy storage component, and its capacitance value can be 100nF; the output end of the voltage follower 20421 can be connected to the controller 301.

[0140] In the embodiment of the present application, the resistor divider unit 202 includes two 4M voltage-dividing resistors and an 80K sampling resistor 2032. The 80K sampling resistor divides the voltage with the two 4M voltage-dividing resistors, and a first capacitor C1 is connected in parallel with the 80K sampling resistor. When the first switch S1 and the second switch S2 are closed, and the third switch S3 and the fourth switch S4 are open, the first capacitor C1 is fully charged, and when fully charged, the voltage is equal to the voltage across the 80K sampling resistor. When the first switch S1 and the second switch S2 are open, and the third switch S3 and the fourth switch S4 are closed, the first capacitor C1 is connected to the voltage follower 20421, and the voltage across the 80K sampling resistor is transmitted to the controller through the voltage follower 20421. When the first switch S1 and the second switch S2 are open, the voltage sampling unit is disconnected from the high-voltage circuit, and the high input impedance and low output impedance characteristics of the voltage follower 20421 are utilized to isolate the high and low voltages.

[0141] It should be noted that the controller 301 can also be used to control the switch unit, that is, to control the on / off of the first switch group 2031, including the first switch S1 and the second switch S2, and the on / off of the second switch group 2032, including the third switch S3 and the fourth switch S4, in the switch unit in the aforementioned embodiment. The controller 301 can preset the time periods for energy storage and release of the energy storage component 2041, that is, the time periods for the on / off of the first and second switches 2031 and 2032, based on the different capacities of the energy storage component 2041 in the voltage sampling unit. For example, at the beginning of the energy storage time period, the controller 301 sends a control command to the switches in the switch unit, causing the first switch group 2031 to turn on, the second switch group 2032 to turn off, and the energy storage component 2041 to store energy. At the end of the energy storage time period, that is, at the beginning of the energy release time period, the controller 301 sends a control command to the switches in the switch unit 203, causing the first switch group 2031 to turn off, the second switch group 2032 to turn on, and the energy storage component 2041 to release energy.

[0142] In addition, the controller 301 can also be used to control the on and off of the fifth switch in the above embodiment, thereby controlling the working state of the high-voltage sampling circuit 20, powering off the high-voltage sampling circuit 20 when high-voltage sampling is not required, and entering the sampling state when high-voltage sampling is required, thereby saving energy consumption.

[0143] An embodiment of the present disclosure provides a battery management system, in which a controller controls the opening and closing of a switch unit to ensure the normal operation of a high-voltage sampling circuit.

[0144] The above description is merely a preferred embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

[0145] The embodiment of the present disclosure further provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the steps of the thermal control method provided in the above method embodiment.

[0146] It should be understood that the description of the above storage medium and device embodiments is similar to the description of the above method embodiments and has similar beneficial effects as the method embodiments. For technical details not disclosed in the storage medium, storage medium, and device embodiments of the present disclosure, please refer to the description of the method embodiments of the present disclosure for understanding.

[0147] It should be understood that "one embodiment" or "an embodiment" or "some embodiments" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present disclosure. Therefore, "in one embodiment" or "in an embodiment" or "in some embodiments" appearing throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present disclosure, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present disclosure. The serial numbers of the embodiments of the present disclosure are for description only and do not represent the advantages and disadvantages of the embodiments. The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other. For the sake of brevity, they will not be repeated here.

[0148] It should also be noted that, in this disclosure, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0149] The serial numbers of the above-mentioned embodiments of the present disclosure are for description only and do not represent the advantages or disadvantages of the embodiments.

[0150] The methods disclosed in the several method embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method embodiments.

[0151] The features disclosed in the several product embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new product embodiments.

[0152] The features disclosed in several method or device embodiments provided in this disclosure may be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0153] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

[0154] The above description is merely a preferred embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A high-voltage sampling circuit, comprising a resistor voltage divider unit, a switch unit and a voltage sampling unit, wherein two ends of the resistor voltage divider unit are respectively connected to two ends of a high-voltage bus, and an output end of the resistor voltage divider unit is connected to the voltage sampling unit through the switch unit, wherein: The resistor voltage dividing unit is configured to divide the bus voltage at both ends of the high-voltage bus to generate a first voltage signal; The voltage sampling unit includes an energy storage component and an isolation component, and is configured to store energy in the energy storage component through the first voltage signal when the switch unit is in a first state; and when the switch unit is in a second state, convert the energy stored in the energy storage component into a second voltage signal, and output the second voltage signal as a third voltage signal through the isolation component.

2. The high voltage sampling circuit according to claim 1, wherein: The resistor voltage-dividing unit includes a plurality of voltage-dividing resistors, wherein: One of the plurality of voltage-dividing resistors is used as a sampling resistor, and output terminals are drawn out from both ends of the sampling resistor and connected to the switch unit.

3. The high voltage sampling circuit according to claim 2, wherein: The plurality of voltage-dividing resistors include a first resistor, a second resistor and a third resistor, and the second resistor serves as the sampling resistor; wherein: The first end of the first resistor is connected to the positive terminal of the high-voltage bus, and the second end of the first resistor is connected to the first end of the second resistor and the first input terminal of the switch unit respectively; The first end of the third resistor is connected to the second end of the second resistor and the second input end of the switch unit respectively, and the second end of the third resistor is connected to the negative terminal of the high-voltage bus.

4. The high voltage sampling circuit according to claim 3, wherein: The switch unit comprises a first group of switches and a second group of switches, wherein: The switch unit is in a first state, comprising: the first group of switches is in an on state and the second group of switches is in an off state; The switch unit is in a second state, including: the first group of switches is in an off state and the second group of switches is in an on state.

5. The high voltage sampling circuit according to claim 4, wherein: The first switch group includes a first switch and a second switch, and the second switch group includes a third switch and a fourth switch; wherein: The first end of the first switch is connected to the second end of the first resistor and the first end of the second resistor as the first input end of the switch unit, the second end of the first switch is connected to the first end of the energy storage component and the first end of the third switch, and the second end of the third switch is connected to the input end of the isolation component as the first output end of the switch unit; The first end of the second switch is used as the second input end of the switch unit and is connected to the first The second end of the second resistor is connected to the first end of the third resistor, the second end of the second switch is respectively connected to the second end of the energy storage component and the first end of the fourth switch, and the second end of the fourth switch is grounded as the second output end of the switch unit.

6. The high voltage sampling circuit according to claim 5, wherein: The energy storage component comprises a first capacitor, wherein: The first end of the first capacitor is connected to the connection line between the first switch and the third switch as the first end of the energy storage component, and the second end of the first capacitor is connected to the connection line between the second switch and the fourth switch as the second end of the energy storage component.

7. The high voltage sampling circuit according to claim 6, wherein: The first capacitor is used to store energy in the first capacitor according to the sampled voltage across the second resistor when the first switch and the second switch are in the on state and the third switch and the fourth switch are in the off state.

8. The high voltage sampling circuit according to claim 6, wherein: The first capacitor is further used to convert the energy stored in the first capacitor into the second voltage signal and transmit the second voltage signal to the isolation component when the first switch and the second switch are in the disconnected state and the third switch and the fourth switch are in the on state.

9. The high voltage sampling circuit according to any one of claims 1 to 8, wherein: The isolation component comprises a voltage follower, wherein: The positive input terminal of the voltage follower is connected to the first output terminal of the switch unit, and the negative input terminal of the voltage follower is connected to the output terminal of the voltage follower, for outputting the third voltage signal.

10. The high voltage sampling circuit according to any one of claims 1 to 8, wherein: The isolation component comprises a voltage follower and a fourth resistor, wherein: The positive input terminal of the voltage follower is connected to the first output terminal of the switch unit, the negative input terminal of the voltage follower is connected to the first end of the fourth resistor, and the second end of the fourth resistor is connected to the output terminal of the voltage follower for outputting the third voltage signal.

11. The high voltage sampling circuit according to any one of claims 1 to 10, wherein: The resistor voltage-dividing unit further includes a fifth switch, and the fifth switch is connected between a plurality of voltage-dividing resistors in the resistor voltage-dividing unit, wherein: The fifth switch is used to control the on-off of the resistor voltage dividing unit to control the working state of the high-voltage sampling circuit.

12. The high voltage sampling circuit according to any one of claims 1 to 10, wherein: The resistor voltage-dividing unit further includes a fifth switch, and the fifth switch is connected between the voltage-dividing resistor in the resistor voltage-dividing unit and the positive terminal of the high-voltage bus, wherein: The fifth switch is used to control the on-off of the resistor voltage dividing unit to control the working state of the high-voltage sampling circuit.

13. A battery management system, comprising a high voltage sampling circuit and a controller according to any one of claims 1 to 12, wherein: The output end of the high-voltage sampling circuit is connected to the controller, and is used to provide the third voltage signal output by the high-voltage sampling circuit to the controller.

14. The battery management system according to claim 13, wherein: The controller is further used to send a control command to the switch in the switch unit, and the control command is used to control the switch in the switch unit to be in an on state or an off state.

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