Precision sampling circuit, control method and storage medium for large energy storage batteries with small current

Abstract

This application discloses a precise sampling circuit, control method, and storage medium for large energy storage batteries that take into account both small currents. The sampling circuit is applicable to large energy storage batteries. The sampling circuit is connected between the battery and the battery output terminal and includes: a circuit breaker, a positive relay, a fuse, a battery output terminal, a negative relay, a Hall sensor, a DC-DC module, and a battery management system (BMS). The input end of the DC-DC module is connected in parallel with the battery via a circuit breaker, and its output end is connected to the battery management system (BMS). When the circuit breaker is closed, the battery management system (BMS) starts to operate and controls the positive and negative relays to close. When a small current passes through the circuit, the battery management system (BMS) samples the voltage signal of the small current output channel (CH1) and converts it to obtain a small current. When a large current passes through the circuit, the battery management system (BMS) samples the voltage signal of the large current output channel (CH2) and converts it to obtain a large current. This application can improve the small current sampling accuracy of large energy storage batteries.

Description

Technical Field

[0001] The present application relates to the field of current sampling technology, and in particular to a precise sampling circuit, control method and storage medium for large energy storage batteries and small currents. Background Art

[0002] Large-scale energy storage batteries are battery systems with large capacities (typically exceeding megawatt-hours) that utilize electrochemical energy storage technology. These systems can store and release large amounts of electrical energy to meet power system or industrial needs. With the development of the new energy industry, the application of large-scale energy storage battery systems is becoming increasingly widespread.

[0003] The battery's SOC (battery state of charge, also known as remaining capacity) is a key parameter for battery energy management. User-side operating scenarios have increasingly higher requirements for parameters such as current and SOC. Large-scale energy storage battery systems also have different user-side operating scenarios. Some battery systems are connected to a smaller load, or the set charge and discharge power and current are small, so the charge and discharge current during battery operation is also smaller; the connected load is large, or the set charge and discharge power and current are large, then the charge and discharge current during battery operation is also greater; when large energy storage batteries are charged and discharged with a small current for a long time, we find that the cumulative error of the battery SOC will become larger and larger, and the SOC displayed by the battery does not match the actual voltage. For example, the SOC is low at high voltage and high at low voltage.

[0004] The fundamental reason for this phenomenon is that the larger the battery capacity, the higher the battery charging and discharging current. Current system designs for large energy storage batteries often require the use of large-scale shunts, sampling resistors or single-channel Hall sensors. Due to problems such as range measurement errors, it is impossible to take into account the sampling of small currents, resulting in large small current detection errors, which in turn affects the estimation of battery SOC.

[0005] Therefore, how to improve the small current sampling accuracy of large energy storage batteries is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0006] In response to the above problems, the purpose of this application is to provide a large energy storage battery with a precise sampling circuit, control method and storage medium that take into account small currents, which can improve the small current sampling accuracy of large energy storage batteries.

[0007] According to one aspect of the present application, a precision sampling circuit for a large energy storage battery is provided, which can take into account both small currents and large energy storage batteries. The sampling circuit is suitable for large energy storage batteries and is connected between the battery and the battery output terminal, including:

[0008] The positive pole of the battery is connected in series with the circuit breaker, positive relay, fuse, and finally connected to the positive pole of the battery output terminal;

[0009] The negative pole of the battery is connected in series with the negative relay and the Hall sensor, and finally connected to the negative pole of the battery output terminal;

[0010] The sampling circuit also includes a DC-DC module and a battery management system BMS; the input end of the DC-DC module is connected in parallel with the battery via a circuit breaker, and its output end is connected to the battery management system BMS for powering the battery management system BMS; the battery management system BMS is connected to the positive relay and the negative relay;

[0011] The Hall sensor settings are:

[0012] The Hall sensor is provided with terminals A, B, C, and D, which are respectively connected to the CH2 terminal, +Vc terminal, 0V terminal, and CH1 terminal of the battery management system BMS; the Hall sensor is provided with a first Hall chip corresponding to the small current output channel CH1, which outputs the voltage signal between the CH1 terminal and the 0V terminal; the Hall sensor is also provided with a second Hall chip corresponding to the large current output channel CH2, which outputs the voltage signal between the CH2 terminal and the 0V terminal; the Hall sensor uses the following output formula:

[0013] Vout=1 / 2VCC±(2*IP / IPN), where Vout represents the output voltage of the Hall sensor, IP represents the actual input current, and IPN represents the rated current of the Hall sensor.

[0014] The battery management system BMS is set to:

[0015] When the circuit breaker is closed, the battery management system BMS starts to control the positive relay and negative relay to close. When a small current passes through the circuit, the battery management system BMS samples the voltage signal of the small current output channel CH1 and obtains the small current after conversion. When a large current passes through the circuit, the battery management system BMS samples the voltage signal of the large current output channel CH2 and obtains the large current after conversion.

[0016] Preferably, in some embodiments of the present application, the initial state of the circuit breaker, the positive relay, and the negative relay is an off state.

[0017] Preferably, in some embodiments of the present application, the measurement range of the first Hall chip is ±1A~±5A, the measurement range of the second Hall chip is ±5A~±3000A, the output of the small current output channel CH1 and the large current output channel CH2 are both 2.5±2V, and 1 / 2VCC corresponds to 2V in the output formula of the Hall sensor.

[0018] Preferably, in some embodiments of the present application, the BMS outputs a 24V drive signal to control the positive relay and the negative relay to close.

[0019] Preferably, in some embodiments of the present application, the Hall sensor is configured as:

[0020] A current is applied to the sampling circuit through a high-precision external device, and the Hall sensor feeds back two voltage output signals to the battery management system BMS through the first Hall chip and the second Hall chip respectively. After conversion and processing, the battery management system BMS obtains two current values respectively, and compares the two current values with the current value applied by the external device to determine which of the two current values is more accurate; different currents are applied to the sampling circuit multiple times through high-precision external devices for verification, and the value ranges of the small current output channel CH1 and the large current output channel CH2 are respectively obtained.

[0021] Preferably, in some embodiments of the present application, the battery management system BMS is configured as follows:

[0022] When the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the small current output channel CH1, the control selects the value of the small current output channel CH1. When the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the large current output channel CH2, the control selects the value of the small current output channel CH1.

[0023] According to another aspect of the present application, the present application also provides a method for controlling a precise sampling circuit for a large energy storage battery with low current, comprising the sampling circuit of any one of the above embodiments:

[0024] When a small current passes through the sampling circuit, the battery management system BMS samples the voltage signal of the small current output channel CH1 and obtains the small current after conversion. When a large current passes through the circuit, the battery management system BMS samples the voltage signal of the large current output channel CH2 and obtains the large current after conversion.

[0025] Preferably, in some embodiments of the present application, the value ranges of the low current output channel CH1 and the high current output channel CH2 are obtained by the following steps:

[0026] A current is applied to the sampling circuit through a high-precision external device, and the Hall sensor feeds back two voltage output signals to the battery management system BMS through the first Hall chip and the second Hall chip respectively. After conversion and processing, the battery management system BMS obtains two current values respectively, and compares the two current values with the current value applied by the external device to determine which of the two current values is more accurate; different currents are applied to the sampling circuit multiple times through high-precision external devices for verification, and the value ranges of the small current output channel CH1 and the large current output channel CH2 are respectively obtained.

[0027] Preferably, in some embodiments of the present application, when the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the small current output channel CH1, the control selects the value of the small current output channel CH1; when the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the large current output channel CH2, the control selects the value of the small current output channel CH1.

[0028] According to another aspect of the present application, the present application further provides a computer-readable storage medium having computer instructions stored thereon. When the computer instructions are executed by a processor, the sampling circuit control method of any one of the above embodiments can be implemented.

[0029] It should be understood that within the scope of this application, the above-mentioned technical features of this application and the technical features described in detail below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be listed here one by one.

[0030] Compared with the existing technology, this application has the following technical effects:

[0031] This application achieves accurate sampling of the full range of current in large energy storage batteries through a collaborative sampling mechanism of small current output channels and large current output channels, especially solving the industry problem of excessive errors in small current sampling with traditional single-sensor solutions; this application adopts a magnetic circuit isolation design with independent layout of the first Hall chip and the second Hall chip to avoid crosstalk, so that the sampling device is electrically isolated from the main circuit, avoiding leakage current loss and ensuring system safety. The non-contact sampling solution completely eliminates the power loss caused by traditional sampling resistors, and has been tested to improve the system energy efficiency by more than 2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other features and advantages of the present application will become more apparent by describing in detail example embodiments thereof with reference to the accompanying drawings.

[0033] Figure 1 A schematic diagram of a precise sampling circuit for a large energy storage battery and a small current according to an embodiment of the present application is shown.

[0034] Figure 2 The graph shows the relationship between the voltage output by the Hall sensor of a precise sampling circuit for a large energy storage battery with low current and the rated current calibrated by the Hall sensor in accordance with an embodiment of the present application.

[0035] Reference numerals: 1 battery; 2 circuit breaker; 3 positive relay; 4 fuse; 5 battery output terminal; 6 negative relay; 7 Hall sensor; 8 DC-DC module; 9 battery management system BMS; 71 first Hall chip; 72 second Hall chip DETAILED DESCRIPTION

[0036] To make the purpose, technical solutions, beneficial effects, and significant improvements of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, all the embodiments described are only some of the embodiments of this application, not all of them; based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0037] The present application will be further described below in conjunction with specific implementations. It should be understood that these embodiments are only used to illustrate the present application and are not intended to limit the scope of the present application.

[0038] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment herein. The appearance of such phrases in various places in the specification does not necessarily refer to the same embodiment, nor does it limit mutually exclusive independent or alternative embodiments. Those skilled in the art will appreciate that an embodiment herein may be combined with other embodiments as long as no structural conflicts arise.

[0039] In the description herein, unless otherwise specified or limited, the technical terms "installed," "connected," and "connected" should be understood broadly, and may refer to a movable connection, a fixed connection or integration, or connection via a connector. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this application based on the specific circumstances.

[0040] In the description of this document, terms indicating orientation or positional relationships, such as "up", "down", "left", "right", "horizontal", "vertical", "height", "length", and "width", are intended to accurately describe the embodiments and simplify the description, but are not intended to limit the parts or structures involved to having a specific orientation, being installed or operated in a specific orientation, and should not be understood as limiting the embodiments in this document.

[0041] In the description herein, terms such as "first" and "second" are used only to distinguish different objects and should not be understood to indicate relative importance or to limit the quantity, specific order, or primary and secondary relationship of the described technical features. In the description herein, "plurality" means at least two.

[0042] Embodiments of the present application will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present application, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts.

[0043] Figure 1The figure shows a schematic diagram of a large energy storage battery and a small current precision sampling circuit according to an embodiment of the present application. Figure 1 As shown, the present application provides a large energy storage battery with a small current precision sampling circuit, which is suitable for large energy storage batteries and is connected between the battery 1 and the battery output terminal 5, including:

[0044] The positive terminal of battery 1 is connected in series with circuit breaker 2, positive relay 3, fuse 4, and finally connected to the positive terminal of battery output terminal 5;

[0045] The negative pole of battery 1 is connected in series with negative relay 6 and Hall sensor 7, and finally connected to the negative pole of battery output terminal 5;

[0046] The sampling circuit also includes a DC-DC module 8 and a battery management system BMS9; the input end of the DC-DC module 8 is connected in parallel with the battery 1 via the circuit breaker 2, and the output end thereof is connected to the battery management system BMS9 for powering the battery management system BMS9; the battery management system BMS9 is connected to the positive relay 3 and the negative relay 6;

[0047] Hall sensor 7 is set to:

[0048] The Hall sensor 7 is provided with an A terminal, a B terminal, a C terminal, and a D terminal, which are respectively connected to the CH2 terminal, the +Vc terminal, the 0V terminal, and the CH1 terminal of the battery management system BMS9; the Hall sensor 7 is provided with a first Hall chip 71, which corresponds to the small current output channel CH1 and outputs a voltage signal between the CH1 terminal and the 0V terminal; the Hall sensor is also provided with a second Hall chip 72, which corresponds to the large current output channel CH2 and outputs a voltage signal between the CH2 terminal and the 0V terminal;

[0049] Specifically, in one embodiment of the present application, combined with Figure 1 , close circuit breaker 2, and the voltage of battery 1 is transmitted to the Vin terminal of DC-DC module 8. The Vout terminal of DC-DC module 8 is connected to the P+ and P- terminals of battery management system BMS9 to power the battery management system BMS9. After the battery management system BMS9 starts running, it outputs a 24V drive signal through the RL4+ and RL4 terminals to control the closing of negative relay 6, which passes through the Hall sensor 7 and then to the battery output terminal 5; and outputs a 24V drive signal through the RL2+ and RL2- terminals to control the closing of positive relay 3, which passes through fuse 4 and then to the battery output terminal 5.

[0050] The Hall sensor 7 uses the following output formula:

[0051] Vout=1 / 2VCC±(2*IP / IPN), where Vout represents the output voltage of the Hall sensor 7, IP represents the actual input current, and IPN represents the rated current of the Hall sensor 7;

[0052] Specifically, in one embodiment of the present application, when current passes through the Hall sensor 7, a magnetic field is generated. Under the action of the magnetic field, the carriers in the current will be deflected and a potential difference signal will be generated on both sides of the Hall sensor 7. The processing circuit will convert the potential difference into a voltage signal, and output the voltage signal after linear amplification and filtering. Two Hall chips are used inside the Hall sensor 7, large current corresponds to the second Hall chip 72, and small current corresponds to the first Hall chip 71. The corresponding output signals are two-channel, small current corresponds to output channel CH1, and large current corresponds to output channel CH2. The outputs are both 2.5±2V, and 1 / 2VCC corresponds to 2V. When measuring large current, the battery management system BMS9 samples the output value of the CH2 channel, and when measuring small current, the battery management system BMS9 samples the output value of the CH1 channel.

[0053] The battery management system BMS9 is set to:

[0054] When the circuit breaker 2 is closed, the battery management system BMS9 starts to operate and controls the positive relay 3 and the negative relay 6 to be closed. When a small current passes through the circuit, the battery management system BMS9 samples the voltage signal of the small current output channel CH1 and obtains the small current after conversion. When a large current passes through the circuit, the battery management system BMS9 samples the voltage signal of the large current output channel CH2 and obtains the large current after conversion.

[0055] Preferably, in some embodiments of the present application, the battery output terminal 5 is connected to an inverter (not shown in the figure) to build an energy storage system, the inverter charges and discharges the battery 1 through the battery output terminal 5, and the battery management system BMS9 supplies power to the Hall sensor 7 through the +Vc and 0V terminals. When the current passing through the circuit is large, the battery management system BMS9 samples the voltage signal between CH2 and 0V, and then obtains the current through conversion processing; when the current passing through the circuit is small, the battery management system BMS9 samples the voltage signal between CH1 and 0V, and then obtains the current through conversion processing.

[0056] Preferably, in some embodiments of the present application, the initial state of the circuit breaker 2 , the positive relay 3 , and the negative relay 6 is an off state.

[0057] Preferably, in some embodiments of the present application, the measurement range of the first Hall chip is ±1A~±5A, the measurement range of the second Hall chip is ±5A~±3000A, the output of the small current output channel CH1 and the large current output channel CH2 are both 2.5±2V, and 1 / 2VCC corresponds to 2V in the output formula of the Hall sensor 7.

[0058] Specifically, in one embodiment of the present application, the outputs of the small current output channel CH1 and the large current output channel CH2 are both 2.5±2V. In the output formula of the Hall sensor 7, 1 / 2VCC corresponds to 2V. The relationship curve between the voltage output by the Hall sensor 7 and the rated current calibrated by the Hall sensor 7 is as follows: Figure 2 shown.

[0059] Preferably, in some embodiments of the present application, the battery management system BMS9 outputs a 24V drive signal to control the positive relay 3 and the negative relay 6 to close.

[0060] Preferably, in some embodiments of the present application, the Hall sensor 7 is further configured as:

[0061] A current is applied to the sampling circuit through a high-precision external device (not shown in the figure), and the Hall sensor 7 feeds back two voltage output signals to the battery management system BMS9 through the first Hall chip 71 and the second Hall chip 72 respectively. After conversion and processing, the battery management system BMS9 obtains two current values, which are compared with the current value applied by the external device to determine which of the two current values is more accurate. Different currents are applied to the sampling circuit multiple times through the high-precision external device for verification, and the value ranges of the small current output channel CH1 and the large current output channel CH2 are obtained respectively.

[0062] Preferably, in some embodiments of the present application, the battery management system BMS9 is further configured to:

[0063] When the battery management system BMS9 detects that the current passing through the sampling circuit is within the value range of the small current output channel CH1, the control selects the value of the small current output channel CH1. When the battery management system BMS9 detects that the current passing through the sampling circuit is within the value range of the large current output channel CH2, the control selects the value of the small current output channel CH1.

[0064] According to another aspect of the present application, the present application also provides a method for controlling a precise sampling circuit for a large energy storage battery with low current, comprising the sampling circuit of any one of the above embodiments:

[0065] When a small current passes through the sampling circuit, the battery management system BMS9 samples the voltage signal of the small current output channel CH1 and obtains the small current after conversion. When a large current passes through the circuit, the battery management system BMS9 samples the voltage signal of the large current output channel CH2 and obtains the large current after conversion.

[0066] Preferably, in some embodiments of the present application, the value ranges of the low current output channel CH1 and the high current output channel CH2 are obtained by the following steps:

[0067] A current is applied to the sampling circuit through a high-precision external device, and the Hall sensor 7 feeds back two voltage output signals to the battery management system BMS9 through the first Hall chip 71 and the second Hall chip 72 respectively. After conversion and processing, the battery management system BMS9 obtains two current values respectively, and compares the two current values with the current value applied by the external device to determine which of the two current values is more accurate; different currents are applied to the sampling circuit multiple times through a high-precision external device for verification, and the value ranges of the small current output channel CH1 and the large current output channel CH2 are obtained respectively.

[0068] Preferably, in some embodiments of the present application, when the battery management system BMS9 detects that the current passing through the sampling circuit is within the value range of the small current output channel CH1, the control selects the value of the small current output channel CH1; when the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the large current output channel CH2, the control selects the value of the small current output channel CH1.

[0069] According to another aspect of the present application, the present application further provides a computer-readable storage medium having computer instructions stored thereon. When the computer instructions are executed by a processor, the sampling circuit control method provided by any one of the above embodiments can be implemented.

[0070] This application describes a circuit, control method, and storage medium for precise sampling of small currents in large energy storage batteries. Two Hall effect sensor chips with different ranges are provided for small and large currents, respectively. Dynamic switching and intelligent control via the BMS system enable high-precision sampling of the entire current range, from mA to kA, for large energy storage batteries. This significantly improves the accuracy of battery circuit sampling and is particularly suitable for megawatt-hour energy storage scenarios, which have stringent current detection requirements. Furthermore, the circuit design includes three levels of protection: circuit breakers, relays, and fuses, as well as an independently powered DC-DC module, significantly enhancing the safety and reliability of the system.

[0071] The above describes the preferred embodiments of the present application. It should be understood that the present application is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-mentioned disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present application without departing from the scope of the technical solutions of the present application, or modify them into equivalent embodiments with equivalent changes, which does not affect the substantive content of the present application. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application that do not depart from the content of the technical solutions of the present application are still within the scope of protection of the technical solutions of the present application.

Claims

1. A precise sampling circuit for large energy storage batteries and small currents, characterized by: The sampling circuit is suitable for a large energy storage battery. The sampling circuit is connected between the battery and the battery output terminal and includes: The positive electrode of the battery is connected in series with a circuit breaker, a positive relay, and a fuse, and finally connected to the positive electrode of the battery output terminal; The negative electrode of the battery is connected in series with a negative relay and a Hall sensor in sequence, and finally connected to the negative electrode of the battery output terminal; The sampling circuit further includes a DC-DC module and a battery management system BMS; the input end of the DC-DC module is connected in parallel with the battery via a circuit breaker, and the output end thereof is connected to the battery management system BMS for powering the battery management system BMS; the battery management system BMS is connected to the positive relay and the negative relay; The Hall sensor is configured as follows: The Hall sensor is provided with A, B, C, and D terminals, which are respectively connected to the CH2 terminal, +Vc terminal, 0V terminal, and CH1 terminal of the battery management system BMS; the Hall sensor is provided with a first Hall chip corresponding to the small current output channel CH1, which outputs a voltage signal between the CH1 terminal and the 0V terminal; the Hall sensor is also provided with a second Hall chip corresponding to the large current output channel CH2, which outputs a voltage signal between the CH2 terminal and the 0V terminal; the Hall sensor adopts the following output formula: Vout=1 / 2VCC±(2*IP / IPN), where Vout represents the output voltage of the Hall sensor, IP represents the actual input current, and IPN represents the rated current of the Hall sensor. The battery management system BMS is configured as follows: When the circuit breaker is closed, the battery management system BMS starts to control the positive relay and the negative relay to close. When a small current passes through the circuit, the battery management system BMS samples the voltage signal of the small current output channel CH1 and obtains the small current after conversion. When a large current passes through the circuit, the battery management system BMS samples the voltage signal of the large current output channel CH2 and obtains the large current after conversion.

2. The sampling circuit according to claim 1, wherein: The initial states of the circuit breaker, the positive relay and the negative relay are off.

3. The sampling circuit according to claim 1, wherein: The measurement range of the first Hall chip is ±1A~±5A, the measurement range of the second Hall chip is ±5A~±3000A, the output of the small current output channel CH1 and the large current output channel CH2 are both 2.5±2V, and 1 / 2VCC corresponds to 2V in the output formula of the Hall sensor.

4. The sampling circuit according to claim 1, wherein: The BMS outputs a 24V drive signal to control the positive relay and the negative relay to close.

5. The sampling circuit according to claim 1, wherein: The Hall sensor is configured as follows: A current is applied to the sampling circuit through a high-precision external device, and the Hall sensor feeds back two voltage output signals to the battery management system BMS through the first Hall chip and the second Hall chip respectively. The battery management system BMS obtains two current values after conversion processing, and compares the two current values with the current value applied by the external device to determine which of the two current values is more accurate; different currents are applied to the sampling circuit by the high-precision external device multiple times for verification, and the value ranges of the small current output channel CH1 and the large current output channel CH2 are respectively obtained.

6. The sampling circuit according to claim 5, characterized in that: The battery management system BMS is configured as follows: When the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the small current output channel CH1, it controls the selection of the value of the small current output channel CH1. When the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the large current output channel CH2, it controls the selection of the value of the large current output channel CH2.

7. A method for controlling a precise sampling circuit for a large energy storage battery with low current, characterized in that: The sampling circuit according to any one of claims 1 to 6: When a small current passes through the sampling circuit, the battery management system BMS samples the voltage signal of the small current output channel CH1 and obtains the small current after conversion. When a large current passes through the circuit, the battery management system BMS samples the voltage signal of the large current output channel CH2 and obtains the large current after conversion.

8. The sampling circuit control method according to claim 7, wherein: The value ranges of the low current output channel CH1 and the high current output channel CH2 are obtained by the following steps: A current is applied to the sampling circuit through a high-precision external device, and the Hall sensor feeds back two voltage output signals to the battery management system BMS through the first Hall chip and the second Hall chip respectively. The battery management system BMS obtains two current values after conversion processing, and compares the two current values with the current value applied by the external device to determine which of the two current values is more accurate; different currents are applied to the sampling circuit by the high-precision external device multiple times for verification, and the value ranges of the small current output channel CH1 and the large current output channel CH2 are respectively obtained.

9. The sampling circuit control method according to claim 8, wherein: When the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the small current output channel CH1, it controls the selection of the value of the small current output channel CH1. When the battery management system BMS detects that the current passing through the sampling circuit is within the value range of the large current output channel CH2, it controls the selection of the value of the large current output channel CH2.

10. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by a processor, the sampling circuit control method according to any one of claims 7 to 9 is implemented.

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