BMS test system and method

Abstract

The invention discloses a BMS test system and method. The BMS test system comprises a power supply unit, an MCU control test unit, a cell voltage simulation unit, a cell temperature simulation unit, a switching value input and output unit and a communication unit. The power supply unit comprises an isolation power supply module, and the isolation power supply module comprises a power supply input port and two output ports which are respectively used for supplying power to the cell voltage simulation unit and the MCU control test unit; the MCU control test unit is respectively connected with the battery cell voltage simulation unit, the battery cell temperature simulation unit, the switching value input and output unit and the communication unit; the MCU control test unit comprises an MCU, a liquid crystal, a key, a code scanning gun, a USB flash disk interface and a local ROM (Read Only Memory); during testing, selecting a to-be-tested BMS model, and scanning a code to check the model; comparing an error between the set value and the collected value, generating a corresponding test report according to a comparison result, storing the report into a local ROM and transferring the report into a USB flash disk, and continuing or ending the test. The system is high in integration level, controllable in cost, comprehensive in test items and suitable for large-scale application.

Description

Technical Field

[0001] This application relates to the fields of energy storage and new energy technologies, and in particular to a BMS testing system and method. Background Technology

[0002] With the rapid development of energy storage systems and the new energy vehicle industry, lithium-ion batteries are widely used in various power storage and vehicle power systems. As a core component ensuring the safe, stable, and efficient operation of batteries, the reliability of the Battery Management System (BMS) is particularly crucial. During the production process, all functions of the BMS must be comprehensively tested to ensure that it can accurately collect electrical parameters (such as voltage and current) and non-electrical parameters (such as temperature) of the battery pack and achieve effective communication and control functions.

[0003] Currently, the industry commonly uses battery simulators to replace real battery cells for BMS testing, combining them with industrial control computers or PCs and channel switching circuits to build automated testing platforms to improve testing efficiency. For example, Chinese invention patent application CN118625032A discloses a BMS testing system and method that uses battery simulation devices instead of real batteries and a network multi-serial port unit as a hub. The host computer uses the network multi-serial port unit to set and collect simulation parameters such as time synchronization, addressing, voltage, and temperature of the battery simulation device, providing a safe and reliable testing environment for the BMS device. Chinese utility model patent CN221804218U discloses an automated testing system for multi-cell battery BMS, which also uses a battery simulator instead of real batteries to test the BMS. However, existing BMS testing systems still have many shortcomings in practical applications. Battery simulators themselves are expensive, and the number of cell channels that a single device can simulate is limited. In applications such as power storage, 1P52S or even more series-connected battery configurations are commonly used. This results in a large number of channels in the corresponding BMS (Battery Management System) acquisition system, requiring multiple cell simulators to work collaboratively. This leads to high overall system cost and a large footprint, hindering deployment and application in mass production environments. Furthermore, existing battery simulators typically focus only on voltage and temperature simulation, while BMS systems often integrate multiple functional interfaces such as digital input / output and daisy-chain (ISOSPI) cascaded communication. These interfaces cannot be uniformly tested in traditional testing platforms, requiring the construction of additional test benches, further increasing system complexity and testing costs, and reducing the integration and automation of the testing process. Summary of the Invention

[0004] To address the problems existing in the prior art, this application provides a BMS testing system and method. It adopts a highly integrated design, replaces the dedicated cell simulator with a multi-channel voltage reference, and integrates buttons, LCD and USB flash drive interface. It can comprehensively test the voltage / temperature acquisition and communication functions of BMS without a host computer, and automatically generate a complete process report. It has the advantages of low cost, small size, high accuracy and easy mass production.

[0005] Firstly, this application provides a BMS testing system, comprising: The power supply unit is used to supply power to the MCU control test unit and the cell voltage simulation unit. The MCU control test unit, connected to the power supply unit, includes an MCU, an LCD, buttons, a barcode scanner, a USB flash drive interface, and a local ROM memory. The MCU is connected to the LCD, buttons, barcode scanner, USB flash drive interface, and local ROM memory respectively. The cell voltage simulation unit is connected to the power supply unit and the MCU control test unit, and is used to output the set voltage value; The cell temperature simulation unit is connected to the MCU control and testing unit and is used to output the set resistance value; The digital input / output unit is connected to the MCU control and testing unit and is used to output the state value set by the relay. The communication unit is connected to the MCU control test unit and is used to transmit the voltage value, resistance value, and relay status value collected by the BMS system under test to the MCU control test unit.

[0006] In one possible implementation of the first aspect, the power supply unit includes an isolated power module, which includes a power input port, a first output port, and a second output port. The power input port is connected to an external power source; the first output port is connected to the MCU control and testing unit; and the second output port is connected to the cell voltage simulation unit.

[0007] In one possible implementation of the first aspect, the MCU includes an I2C1 interface, a UART1 interface, a USBHOST interface, an SPI3 interface, and several I / O ports; The LCD is connected to the I2C1 interface, the barcode scanner is connected to the UART1 interface, the USB flash drive interface is connected to the USBHOST interface, the local ROM memory is connected to the SPI3 interface, and the button is connected to the first I / O port of the MCU.

[0008] In one possible implementation of the first aspect, the cell voltage simulation unit includes a multi-channel simulated cell voltage output module, each of which includes an isolated power supply, multiple voltage reference chips, and a first multiple-to-one channel switch. The input terminal of the isolated power supply is connected to the second output port of the isolated power supply module in the power supply unit; the output terminal of the isolated power supply is connected to the input terminals of multiple voltage reference chips respectively; the output terminals of the multiple voltage reference chips are connected to the input terminal of the first multi-channel switch; the control terminal of the first multi-channel switch is connected to the second I / O port of the MCU in the MCU control test unit. The MCU controls the first multiplexer through the second I / O port to select one of the multiple voltage reference chips for voltage output. The output voltage of the voltage reference chip covers the output range of the analog battery cell, and the voltage fluctuation range is less than 1mV.

[0009] In one possible implementation of the first aspect, the cell temperature simulation unit includes a multi-channel analog resistor output module, each analog resistor output module including multiple resistors and a second multi-channel switch. The plurality of resistors are respectively connected to the input terminal of the second multi-channel selector; the control terminal of the second multi-channel selector is connected to the third I / O port of the MCU in the MCU control test unit; The MCU controls the second multiple-choice channel selector through the third IO port to select one of the resistance values ​​of multiple resistors for output. The resistance value is converted into temperature and covers the temperature range that the BMS system under test can collect.

[0010] In one possible implementation of the first aspect, the digital input / output unit includes a first relay, a second relay, a first optocoupler, and a second optocoupler; The input terminal of the first relay is connected to the fourth I / O port of the MCU in the MCU control test unit, and the first relay outputs a first switch output signal; the input terminal of the second relay is connected to the fifth I / O port of the MCU in the MCU control test unit, and the second relay outputs a second switch output signal. The input terminal of the first optocoupler is connected to a first digital input signal, and the output terminal of the first optocoupler is connected to the sixth I / O port of the MCU in the MCU control test unit; the input terminal of the second optocoupler is connected to a second digital input signal, and the output terminal of the second optocoupler is connected to the seventh I / O port of the MCU in the MCU control test unit. The MCU collects the first and second digital input signals and controls the opening and closing of the first and second relays.

[0011] In one possible implementation of the first aspect, the communication unit includes an isolated CAN transceiver circuit, a first isolated ISOSPI interface, and a second isolated ISOSPI interface; The input terminal of the isolated CAN transceiver circuit is connected to the CAN interface of the MCU in the MCU control test unit; the output terminal of the isolated CAN transceiver circuit is set as a CAN communication interface; the input terminal of the first isolated ISOSPI interface is connected to the first SPI interface of the MCU in the MCU control test unit, and the output port of the first isolated ISOSPI is set as a first ISOSPI daisy-chain cascade port; the input terminal of the second isolated ISOSPI interface is connected to the second SPI of the MCU in the MCU control test unit, and the output port of the second isolated ISOSPI interface is set as a second ISOSPI daisy-chain cascade port.

[0012] Secondly, this application provides a BMS testing method based on the aforementioned BMS testing system, comprising the following: Connect the power supply and use the button to select the model of the BMS system to be tested; Connect the BMS test system and the BMS system under test; Use the barcode scanner to scan the barcode of the BMS system under test; Determine whether the barcode of the scanned BMS system under test matches the model of the selected BMS system under test; If the barcode and model number match, the MCU outputs a set value 'a' and reads the acquired value 'b' from the BMS system; it calculates the error between the set value 'a' and the acquired value 'b', sets the error range, and determines whether the error between the set value 'a' and the acquired value 'b' is within the error range; if it is within the error range, the LCD displays a pass message and generates a test report T1 based on the test results; otherwise, the LCD displays a fail message and generates a test report T2 based on the test results; the test report is saved to the local ROM memory and imported into an external USB flash drive via the USB flash drive interface; the LCD prompts to connect to the next BMS for testing; it determines whether to end the test; if yes, it ends; otherwise, it reconnects the BMS test system and the BMS system under test. If the barcode and model number are inconsistent, the LCD displays an error message and reconnects the BMS test system and the BMS system under test.

[0013] In one possible implementation of the second aspect, the MCU outputs a setpoint a and reads the acquired value b from the BMS system, including: The MCU controls the first multiple-choice channel switch in the cell voltage simulation unit to output the set voltage value a1 in sequence, and receives the voltage value b1 collected by the BMS system under test through the CAN communication interface and the first isolated ISOSPI interface, and records the voltage value a1 and the voltage value b1. The MCU controls the second multiple-choice channel selector in the cell temperature simulation unit to output the set resistance value a2 in sequence, and receives the resistance value b2 collected by the BMS system under test through the CAN communication interface and the second isolated ISOSPI interface, and records the resistance value a2 and the resistance value b2. The MCU controls the first and second relays in the digital input / output unit to output the set state value a3, and receives the state values ​​b3 of the first and second relays collected by the BMS system under test through the CAN communication interface, and records the state values ​​a3 and b3.

[0014] In one possible implementation of the second aspect, there are multiple sets of set voltage values ​​a1 and / or resistance values, multiple sets of voltage values ​​a1 and / or resistance values ​​a2 are set, and multiple sets of voltage values ​​b1 and / or resistance values ​​a2 are acquired by the BMS system under test.

[0015] In one possible implementation of the second aspect, the step of calculating the error between the set value a and the acquired value b, setting an error range, and determining whether the error between the set value a and the acquired value b is within the error range includes: When the error range between the set voltage value a1 and the collected voltage value b1 is within ±5mV, the LCD displays the information. When the error between the set resistance value a2 and the collected resistance value b2 is converted to a temperature value within ±2℃, the LCD displays the information. When the status value a3 set by the first and second relays is consistent with the status value b3 collected by the BMS system under test, the switch action is correct and the LCD displays the pass information.

[0016] In one possible implementation of the second aspect, the state value a3 set by the first relay and the second relay and / or the state value b3 collected by the BMS system under test include two states: on and off.

[0017] Compared with the prior art, this application has the following beneficial effects: 1. By simulating cell voltage with a multi-channel voltage reference chip, the expensive dedicated battery simulator is replaced. The circuit structure is simple, compact, and highly integrated, achieving lower cost, smaller size, and higher testing accuracy.

[0018] 2. The system is equipped with buttons, an LCD screen and a USB flash drive interface. It can independently complete all human-computer interaction, test control and report generation without relying on a host computer. All functions are integrated into a standard 2U chassis, which is convenient for large-scale deployment and production.

[0019] 3. Comprehensive testing functions, supporting integrated testing of BMS voltage acquisition, temperature acquisition, digital input / output, and isolated ISO cascaded communication port and CAN communication port.

[0020] 4. Automatically generate and store reports containing complete test process data, with detailed information that facilitates traceability and analysis. Attached Figure Description

[0021] Figure 1 This is a hardware module block diagram of a BMS testing system provided in an embodiment of this application; Figure 2 This is a flowchart of the steps of a BMS testing method provided in the embodiments of this application; Figure 3 This is a flowchart illustrating the steps of outputting a set value and comparing it with the collected values ​​in a BMS testing method provided in this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0023] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0024] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a," "the," and "the" as used in the embodiments of this application are also intended to include the plural forms unless the context clearly indicates otherwise.

[0025] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0026] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0027] like Figure 1 As shown, a BMS test system includes a power supply unit, an MCU control test unit, a cell voltage simulation unit, a cell temperature simulation unit, a digital input / output unit, and a communication unit. The power supply unit is connected to the MCU control test unit and the cell voltage simulation unit respectively, and is used to supply power to the MCU control test unit and the cell voltage simulation unit. The MCU control and testing unit is connected to the cell voltage simulation unit, the cell temperature simulation unit, the digital input / output unit, and the communication unit, respectively.

[0028] Furthermore, the power supply unit includes an isolated power module, which includes a power input port, a first output port, and a second output port. The power input port is connected to an external 220V AC power supply or DC power supply; the first output port is connected to an MCU control and testing unit; and the second output port is connected to a cell voltage simulation unit. In one possible implementation, the first output port is a 5V DC output port, and the second output port is a 12V DC output port.

[0029] Furthermore, the MCU control test unit includes an MCU, an LCD, buttons, a barcode scanner, a USB flash drive interface, and a local ROM memory. The MCU is connected to the LCD, buttons, barcode scanner, USB flash drive interface, and local ROM memory respectively. Specifically, the MCU includes an I2C1 interface, a UART1 interface, a USBHOST interface, an SPI3 interface, and several I / O ports; the LCD is connected to the MCU's I2C1 interface; the barcode scanner is connected to the MCU's UART1 interface; the USB flash drive interface is connected to the MCU's USBHOST interface; the local ROM memory is connected to the MCU's SPI3 interface; and the button is connected to the MCU's first I / O port.

[0030] Furthermore, the cell voltage simulation unit includes a multi-channel simulated cell voltage output module; wherein each simulated cell voltage output module includes an isolated power supply, multiple voltage reference chips, and a first multi-to-one channel switch. Specifically, the input terminal of the isolated power supply is connected to the second output port of the isolated power supply module in the power supply unit; the output terminal of the isolated power supply is connected to the input terminals of multiple voltage reference chips respectively; the output terminals of the multiple voltage reference chips are connected to the input terminals of the first multi-channel selector respectively; the control terminal of the first multi-channel selector is connected to the second I / O port of the MCU in the MCU control test unit, and the MCU controls the first multi-channel selector through the second I / O port to select one of the multiple voltage reference chips for voltage output. The output voltage of the voltage reference chip covers the output range of the analog battery cell, and the voltage fluctuation range is less than 1mV.

[0031] Furthermore, the cell temperature simulation unit includes a multi-channel analog temperature resistor output module, and each analog temperature resistor output module includes multiple precision resistors and a second multi-channel switch. Specifically, the multiple precision resistors are connected to the input terminals of the second multi-channel selector; the control terminal of the second multi-channel selector is connected to the third I / O port of the MCU in the MCU control test unit. The MCU controls the second multi-channel selector through the third I / O port, thereby selecting one of the multiple precision resistors for output. The precision resistor has a resistance accuracy of 0.1%, and the resistance value of the precision resistor, after being converted into temperature, covers the temperature range that the BMS system under test can collect.

[0032] Furthermore, the digital input / output unit includes a first relay, a second relay, a first optocoupler, and a second optocoupler; Specifically, the input terminal of the first relay is connected to the fourth I / O port of the MCU in the MCU control test unit, and the first relay outputs a first switch output signal; the input terminal of the second relay is connected to the fifth I / O port of the MCU in the MCU control test unit, and the second relay outputs a second switch output signal; the input terminal of the first optocoupler is connected to the first switch input signal, and the output terminal of the first optocoupler is connected to the sixth I / O port of the MCU in the MCU control test unit; the input terminal of the second optocoupler is connected to the second switch input signal, and the output terminal of the second optocoupler is connected to the seventh I / O port of the MCU in the MCU control test unit; the MCU acquires the first switch input signal and the second switch input signal, and controls the opening and closing of the first relay and the second relay.

[0033] Furthermore, the communication unit includes an isolated CAN transceiver circuit, a first isolated ISOSPI interface, and a second isolated ISOSPI interface; Specifically, the input terminal of the isolated CAN transceiver circuit is connected to the CAN interface of the MCU in the MCU control test unit, and is connected to the internal CAN controller through the CAN interface; the output terminal of the isolated CAN transceiver circuit is set to a CAN communication interface. The input terminal of the first isolated ISOSPI interface is connected to the first SPI interface of the MCU in the MCU control test unit, and the output terminal of the first isolated ISOSPI interface is set as the first ISOSPI daisy chain cascade port; The input terminal of the second isolated ISOSPI interface is connected to the second SPI interface of the MCU in the MCU control test unit, and the output terminal of the second isolated ISOSPI interface is set as the second ISOSPI daisy chain cascade port.

[0034] It should be understood that the division of processing modules in the above system is only a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. For example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored. Furthermore, the processing modules in the system can be implemented by the processor calling software; for example, the system includes a processor connected to memory, which stores instructions. The processor calls the instructions stored in memory to implement any of the above methods or to implement the functions of each processing unit in the system. Here, the processor is a general-purpose processor, such as a central processing unit or a microprocessor, and the memory can be internal or external to the system.

[0035] like Figure 2 As shown, based on the same inventive concept, this application also provides a BMS testing method based on the BMS testing system, comprising the following steps: S1: Power on and connect to a 220kV AC / DC power supply. Use the buttons to select the model of the BMS to be tested. S2: Connect the BMS test system and the BMS system under test using a dedicated socket; S3: Use a barcode scanner to scan the barcode of the BMS system under test; S4: Determine whether the barcode of the scanned BMS system under test matches the model of the selected BMS system under test; if they match, proceed to S5; otherwise, the LCD displays an error message and returns to step S2. S5: The MCU outputs a set value a, reads the acquired value b from the BMS system under test, and records the set value a and the acquired value b. S6: Calculate the error between the set value a and the collected value b, set the error range, and determine whether the error between the set value a and the collected value b is within the error range; if it is within the error range, the LCD displays a pass message and generates a test report T1 based on the test result; otherwise, the LCD displays a fail message and generates a test report T2 based on the test result. S7: Save the test report to the local ROM memory and import it to the external USB flash drive via the USB flash drive interface. The LCD prompts to connect the next BMS to be tested. S8: Determine whether to end the test. If yes, end the test; otherwise, proceed to step S2.

[0036] Furthermore, in step S5, the set values ​​and collected values ​​include, but are not limited to, voltage values, resistance values, and status values; specifically, they include the following: S5.1: The MCU controls the first multiple-choice channel switch of the cell voltage simulation unit to output the set voltage value a1 in sequence, and receives the voltage value b1 collected by the BMS system under test through the CAN communication interface and the first isolated ISOSPI interface of the communication unit, and records each set voltage value a1 and the voltage value b1 collected by the BMS system under test. S5.2: The second multiple-choice channel selector of the MCU-controlled cell temperature simulation unit outputs the set resistance value a2 in sequence, and receives the resistance value b2 collected by the BMS system under test through the CAN communication interface and the second isolated ISOSPI interface of the communication unit, and records each set resistance value a2 and the resistance value b2 collected by the BMS system under test. S5.3: The MCU controls the first and second relays in the digital input / output unit to output the set state value a3, and receives the state values ​​b3 of the first and second relays collected by the BMS system under test through the CAN communication interface of the communication unit, and records the set state value a3 and the state value b3 collected by the BMS system under test.

[0037] In one implementation, the voltage value a1 set in step S5.1 can be multiple sets. Depending on the different battery cells, multiple sets of voltage values ​​a1 can be set and multiple sets of voltage values ​​b1 can be collected by the BMS system under test.

[0038] In one implementation, the resistance value a2 set in step S5.2 can be multiple sets, and multiple sets of a2 can be set according to different temperatures, and multiple sets of resistance values ​​b2 can be collected by the BMS system under test.

[0039] Furthermore, step S6 specifically includes the following: When the error range between the set voltage value a1 and the collected voltage value b1 is within ±5mV, the LCD displays the information. When the error between the set resistance value a2 and the collected resistance value b2 is converted to a temperature value within ±2℃, the LCD displays the information. The state value a3 set by the first and second relays and the state value b3 collected by the BMS system under test include two states: on and off. When the set state value a3 and the collected state value b3 are consistent, the switch action is correct and the LCD displays the pass information.

[0040] Those skilled in the art will recognize that the units of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components of each example have been generally described in terms of function in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A BMS testing system, characterized in that, include: The power supply unit is used to supply power to the MCU control test unit and the cell voltage simulation unit. The MCU control test unit, connected to the power supply unit, includes an MCU, an LCD, buttons, a barcode scanner, a USB flash drive interface, and a local ROM memory. The MCU is connected to the LCD, buttons, barcode scanner, USB flash drive interface, and local ROM memory respectively. The cell voltage simulation unit is connected to the power supply unit and the MCU control test unit, and is used to output the set voltage value; The cell temperature simulation unit is connected to the MCU control and testing unit and is used to output the set resistance value; The digital input / output unit is connected to the MCU control and testing unit and is used to output the state value set by the relay. The communication unit is connected to the MCU control test unit and is used to transmit the voltage value, resistance value, and relay status value collected by the BMS system under test to the MCU control test unit.

2. The BMS testing system according to claim 1, characterized in that, The power supply unit includes an isolated power module, which includes a power input port, a first output port, and a second output port. The power input port is connected to an external power source; the first output port is connected to the MCU control and testing unit; and the second output port is connected to the cell voltage simulation unit.

3. The BMS testing system according to claim 1, characterized in that, The MCU includes an I2C1 interface, a UART1 interface, a USBHOST interface, an SPI3 interface, and several I / O ports; The LCD is connected to the I2C1 interface, the barcode scanner is connected to the UART1 interface, the USB flash drive interface is connected to the USBHOST interface, the local ROM memory is connected to the SPI3 interface, and the button is connected to the first I / O port of the MCU.

4. The BMS testing system according to claim 1, characterized in that, The cell voltage simulation unit includes a multi-channel simulated cell voltage output module. Each simulated cell voltage output module includes an isolated power supply, multiple voltage reference chips, and a first multi-select channel switch. The input terminal of the isolated power supply is connected to the second output port of the isolated power supply module in the power supply unit; the output terminal of the isolated power supply is connected to the input terminals of multiple voltage reference chips respectively; the output terminals of the multiple voltage reference chips are connected to the input terminal of the first multi-channel switch; the control terminal of the first multi-channel switch is connected to the second I / O port of the MCU in the MCU control test unit. The MCU controls the first multiplexer through the second I / O port to select one of the multiple voltage reference chips for voltage output. The output voltage of the voltage reference chip covers the output range of the analog battery cell, and the voltage fluctuation range is less than 1mV.

5. The BMS testing system according to claim 1, characterized in that, The cell temperature simulation unit includes a multi-channel analog resistor output module, and each analog resistor output module includes multiple resistors and a second multi-channel switch. The plurality of resistors are respectively connected to the input terminal of the second multi-channel selector; the control terminal of the second multi-channel selector is connected to the third I / O port of the MCU in the MCU control test unit; The MCU controls the second multiple-choice channel selector through the third IO port to select one of the resistance values ​​of multiple resistors for output. The resistance value is converted into temperature and covers the temperature range that the BMS system under test can collect.

6. The BMS testing system according to claim 1, characterized in that, The digital input / output unit includes a first relay, a second relay, a first optocoupler, and a second optocoupler; The input terminal of the first relay is connected to the fourth I / O port of the MCU in the MCU control test unit, and the first relay outputs a first switch output signal; the input terminal of the second relay is connected to the fifth I / O port of the MCU in the MCU control test unit, and the second relay outputs a second switch output signal. The input terminal of the first optocoupler is connected to a first digital input signal, and the output terminal of the first optocoupler is connected to the sixth I / O port of the MCU in the MCU control test unit; the input terminal of the second optocoupler is connected to a second digital input signal, and the output terminal of the second optocoupler is connected to the seventh I / O port of the MCU in the MCU control test unit. The MCU collects the first and second digital input signals and controls the opening and closing of the first and second relays.

7. The BMS testing system according to claim 1, characterized in that, The communication unit includes an isolated CAN transceiver circuit, a first isolated ISOSPI interface, and a second isolated ISOSPI interface. The input terminal of the isolated CAN transceiver circuit is connected to the CAN interface of the MCU in the MCU control test unit; the output terminal of the isolated CAN transceiver circuit is set as a CAN communication interface; the input terminal of the first isolated ISOSPI interface is connected to the first SPI interface of the MCU in the MCU control test unit, and the output port of the first isolated ISOSPI is set as the first ISOSPI daisy-chain cascade port. The input terminal of the second isolated ISOSPI interface is connected to the second SPI of the MCU in the MCU control test unit, and the output port of the second isolated ISOSPI interface is set as the second ISOSPI daisy chain cascade port.

8. A BMS testing method based on the BMS testing system, characterized in that, Includes the following: Connect the power supply and use the button to select the model of the BMS system to be tested; Connect the BMS test system and the BMS system under test; Use the barcode scanner to scan the barcode of the BMS system under test; Determine whether the barcode of the scanned BMS system under test matches the model of the selected BMS system under test; If the barcode and model number match, the MCU outputs the set value a and reads the collected value b from the BMS system; it calculates the error between the set value a and the collected value b, sets the error range, and determines whether the error between the set value a and the collected value b is within the error range; if it is within the error range, the LCD displays the pass information and generates a test report T1 based on the test results. Otherwise, the LCD displays a failure message and generates a test report T2 based on the test results; the test report is saved to the local ROM memory and imported into an external USB flash drive through the USB flash drive interface; the LCD prompts to connect to the next BMS for testing; it determines whether to end the test; if yes, it ends; otherwise, it reconnects the BMS test system and the BMS system under test. If the barcode and model number are inconsistent, the LCD displays an error message and reconnects the BMS test system and the BMS system under test.

9. The BMS testing method according to claim 8, characterized in that, The MCU outputs a setpoint value a and reads the acquired value b from the BMS system, including: The MCU controls the first multiple-choice channel switch in the cell voltage simulation unit to output the set voltage value a1 in sequence, and receives the voltage value b1 collected by the BMS system under test through the CAN communication interface and the first isolated ISOSPI interface, and records the voltage value a1 and the voltage value b1. The MCU controls the second multiple-choice channel selector in the cell temperature simulation unit to output the set resistance value a2 in sequence, and receives the resistance value b2 collected by the BMS system under test through the CAN communication interface and the second isolated ISOSPI interface, and records the resistance value a2 and the resistance value b2. The MCU controls the first and second relays in the digital input / output unit to output the set state value a3, and receives the state values ​​b3 of the first and second relays collected by the BMS system under test through the CAN communication interface, and records the state values ​​a3 and b3.

10. The BMS testing method according to claim 9, characterized in that, The set voltage value a1 and / or resistance value are multiple sets. Multiple sets of voltage values ​​a1 and / or resistance values ​​a2 are set, and multiple sets of voltage values ​​b1 and / or resistance values ​​a2 are acquired by the BMS system under test.

11. The BMS testing method according to claim 9, characterized in that, The calculation of the error between the set value a and the acquired value b, setting an error range, and determining whether the error between the set value a and the acquired value b is within the error range includes: When the error range between the set voltage value a1 and the collected voltage value b1 is within ±5mV, the LCD displays the information. When the error between the set resistance value a2 and the collected resistance value b2 is converted to a temperature value within ±2℃, the LCD displays the information. When the status value a3 set by the first and second relays is consistent with the status value b3 collected by the BMS system under test, the switch action is correct and the LCD displays the pass information.

12. The BMS testing method according to claim 11, characterized in that, The state value a3 set by the first relay and the second relay and / or the state value b3 collected by the BMS system under test include two states: on and off.

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