Relay fault detection test method and related assembly

Abstract

The invention discloses a relay fault detection test method and a related component, and the method comprises the steps: adjusting the output voltage of a second power supply, enabling the voltage of a second detection end of a BMS to change, namely, enabling the output voltage of the second power supply to be adjusted with a first preset voltage as a reference, after the BMS outputs the preset instruction, whether the state of the relay is changed or not can be determined according to the voltage difference between the first detection end and the second detection end, namely whether the BMS detects the fault of the relay or not is determined. When the second power supply outputs the first preset voltage, the BMS determines that the relay is in the first preset state after outputting the preset instruction, and when the BMS outputs the preset instruction after adjusting the output voltage of the second power supply according to the preset step length, the state of the relay can be determined to change. The fault triggering critical voltage for triggering the BMS to recognize the fault of the relay can be determined as the first preset voltage, and the BMS is determined to trigger and detect the fault of the relay according to the preset proportion.

Description

Technical Field

[0001] The present invention relates to the field of battery management, and in particular to a test method for relay fault detection and related components. Background Art

[0002] A BMS (battery management system) typically needs to detect the proper functioning of relays connected to the battery packs in the energy storage system. For example, after sending a relay close command, the BMS detects whether the relay closes normally. Furthermore, after sending a relay close command, the BMS detects whether the relay closes normally. A BMS determines a relay failure if the relay fails to execute the relevant command. If the BMS is unable to detect a relay failure, such as if the relay fails to close normally after the BMS sends a relay close command, or fails to shut down normally after the BMS sends a relay close command, and the BMS fails to detect that the relay has not executed the relay close command, the entire energy storage system may not function properly, or even damage components within the energy storage system, resulting in irreversible damage.

[0003] In the prior art, it is only possible to determine whether the BMS can detect that the relay cannot be closed or turned off normally in the extreme case that the relay cannot be closed or turned off normally. However, it is impossible to determine the exact conditions that trigger the BMS to identify the corresponding fault. Therefore, it is impossible to determine whether the BMS detects the fault of the relay according to the set trigger conditions. Summary of the Invention

[0004] The object of the present invention is to provide a test method for relay fault detection and related components. If, when the second power supply outputs a first preset voltage, the BMS determines that the relay is in the first preset state after outputting a preset instruction, and after adjusting the output voltage of the second power supply with a preset step size, the BMS can determine that the state of the relay has changed when outputting the preset instruction again, then it can be determined that the fault triggering critical voltage that triggers the BMS to recognize that the relay has failed is the first preset voltage, and then it can be determined that the BMS has triggered the detection of the relay failure according to the set preset ratio.

[0005] To solve the above technical problems, the present invention provides a test method for relay fault detection, which is applied to a test circuit for relay fault detection. The test circuit includes a first power supply and a second power supply; the first power supply is connected to a first detection terminal of a BMS, the second power supply is directly connected to a second detection terminal of the BMS or is connected to the second detection terminal of the BMS through a relay, and the control terminal of the BMS is connected to the control terminal of the relay;

[0006] The test method includes:

[0007] controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in a first preset state based on a voltage difference between the first detection terminal and the second detection terminal of the BMS after sending a preset instruction to the relay; the first preset voltage is in a preset ratio to the output voltage of the first power supply;

[0008] If it is the first preset state, adjusting the output voltage of the second power supply with a preset step size, and after the adjustment, determining whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay;

[0009] If it is the second preset state, it is determined that the fault trigger critical voltage of the BMS is the first preset voltage; the first preset state and the second preset state are the off state or the closed state, and the first preset state and the second preset state are different.

[0010] Preferably, the second power supply is connected to the second detection terminal of the BMS through the relay;

[0011] Controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in the first preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending a preset instruction to the relay, including:

[0012] controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in a closed state based on a voltage difference between the first detection terminal and the second detection terminal of the BMS after sending a closing instruction to the relay;

[0013] If the relay is in the first preset state, adjusting the output voltage of the second power supply with a preset step size, and determining after the adjustment whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay, including:

[0014] If it is the closed state, the output voltage of the second power supply is reduced by a preset step size, and after adjustment, it is determined whether the BMS determines that the relay is in the off state based on the voltage difference between its own first detection terminal and the second detection terminal after sending the closing instruction to the relay.

[0015] Preferably, the second power supply is directly connected to the second detection terminal of the BMS;

[0016] Controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in the first preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending a preset instruction to the relay, including:

[0017] controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in an off state based on a voltage difference between the first detection terminal and the second detection terminal of the BMS after sending a shut-down command to the relay;

[0018] If the relay is in the first preset state, adjusting the output voltage of the second power supply with a preset step size, and determining after the adjustment whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay, including:

[0019] If it is the shutdown state, the output voltage of the second power supply is increased by a preset step size, and after adjustment, it is determined whether the BMS determines that the relay is in the closed state based on the voltage difference between its own first detection terminal and the second detection terminal after sending the shutdown instruction to the relay.

[0020] Preferably, before controlling the second power supply to output the first preset voltage, the method further includes:

[0021] determining an output voltage of the first power supply;

[0022] The first preset voltage is calculated based on a product of the output voltage and the preset ratio.

[0023] Preferably, if the state is the first preset state, the output voltage of the second power supply is adjusted with a preset step size, and after the adjustment, it is determined whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay, and further includes:

[0024] If it is not the second preset state, it is determined that the fault triggering critical voltage setting of the BMS is abnormal.

[0025] Preferably, after determining that the fault triggering critical voltage setting of the BMS is abnormal, the method further includes:

[0026] The preset ratio setting parameter of the BMS is adjusted until the fault triggering critical voltage of the BMS reaches the first preset voltage.

[0027] To solve the above technical problems, the present invention provides a test system for relay fault detection, which is applied to a test circuit for relay fault detection. The test circuit includes a first power supply and a second power supply, wherein the first power supply is connected to a first detection terminal of a BMS, the second power supply is directly connected to a second detection terminal of the BMS or is connected to the second detection terminal of the BMS through a relay, and the control terminal of the BMS is connected to the control terminal of the relay;

[0028] The test system comprises:

[0029] a control unit, configured to control the second power supply to output a first preset voltage, and determine whether the BMS determines that the relay is in a first preset state based on a voltage difference between the first detection terminal and the second detection terminal of the BMS after sending a preset instruction to the relay; the first preset voltage is in a preset ratio to the output voltage of the first power supply;

[0030] a determining unit, configured to adjust the output voltage of the second power supply by a preset step size if the state is the first preset state, and after the adjustment, determine whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal of the BMS after sending the preset instruction to the relay;

[0031] A determining unit is configured to determine that, if the second preset state is in effect, the fault triggering critical voltage of the BMS is the first preset voltage; the first preset state and the second preset state are an off state or a closed state, and the first preset state and the second preset state are different.

[0032] To solve the above technical problems, the present invention provides a test device for relay fault detection, comprising:

[0033] Memory for storing computer programs;

[0034] The processor is configured to implement the steps of the relay fault detection test method as described above when executing a computer program.

[0035] To solve the above technical problems, the present invention provides a test circuit for relay fault detection, including the test device for relay fault detection as described above, and also including a first power supply and a second power supply, the first power supply is connected to the first detection end of the BMS, the second power supply is directly connected to the second detection end of the BMS or connected to the second detection end of the BMS through a relay, and the control end of the BMS is connected to the control end of the relay.

[0036] To solve the above technical problems, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the test method for relay fault detection as described above are implemented.

[0037] The present application provides a test method and related components for relay fault detection, which adjusts the output voltage of a second power supply to change the voltage at the second detection terminal of a BMS, that is, by adjusting the output voltage of the second power supply with a first preset voltage as a reference, it is determined whether the BMS can determine whether the state of the relay has changed based on the voltage difference between the first detection terminal and the second detection terminal after outputting a preset instruction, that is, whether the BMS has detected a relay fault. If the BMS determines that the relay is in the first preset state after outputting the preset instruction when the second power supply outputs the first preset voltage, and can determine that the state of the relay has changed when the BMS outputs the preset instruction again after adjusting the output voltage of the second power supply with a preset step size, it can be determined that the fault trigger critical voltage that triggers the BMS to recognize that the relay has failed is the first preset voltage, and it is determined that the BMS has triggered the detection of the relay fault according to the set preset ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0039] Figure 1 A flow chart of a test method for relay fault detection provided by this application;

[0040] Figure 2 A schematic diagram of the structure of a test circuit for relay fault detection in the prior art;

[0041] Figure 3 A schematic diagram of a test circuit structure for relay fault detection when testing relay closure fault detection of a BMS in the prior art;

[0042] Figure 4 A schematic diagram of a test circuit structure for relay fault detection when testing relay shutdown fault detection of a BMS in the prior art;

[0043] Figure 5 A schematic diagram of the test circuit structure for relay fault detection when testing relay closure fault detection of a BMS provided in this application;

[0044] Figure 6A schematic diagram of the test circuit structure for relay fault detection when testing the relay shutdown fault detection of the BMS provided in this application;

[0045] Figure 7 A schematic diagram of the structure of a test system for relay fault detection provided by this application;

[0046] Figure 8 A schematic diagram of the structure of a test device for relay fault detection provided by this application;

[0047] Figure 9 A schematic diagram of the structure of a computer-readable storage medium provided in this application. DETAILED DESCRIPTION

[0048] The core of the present invention is to provide a test method and related components for relay fault detection. If the BMS determines that the relay is in the first preset state after outputting a preset instruction when the second power supply outputs the first preset voltage, and can determine that the state of the relay has changed when the BMS outputs the preset instruction again after adjusting the output voltage of the second power supply with a preset step size, then it can be determined that the fault triggering critical voltage that triggers the BMS to recognize that the relay has failed is the first preset voltage, and then it can be determined that the BMS detects that the relay has failed according to the set preset ratio.

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0050] Please refer to Figure 1 , Figure 1 A flow chart of a test method for relay fault detection provided in the present application is provided, which is applied to a test circuit for relay fault detection. The test circuit includes a first power supply DC1 and a second power supply DC2; the first power supply DC1 is connected to a first detection terminal of a BMS, the second power supply DC2 is connected to a second detection terminal of the BMS directly or through a relay, and the control terminal of the BMS is connected to the control terminal of the relay;

[0051] Test methods include:

[0052] S11: Controlling the second power source DC2 to output a first preset voltage, and determining whether the BMS determines that the relay is in a first preset state based on the voltage difference between its first detection terminal and the second detection terminal after sending a preset instruction to the relay; the first preset voltage is in a preset ratio to the output voltage of the first power source DC1;

[0053] BMS usually controls the relay connected to the battery pack, such as controlling the relay to turn on or off. If the relay does not normally execute the BMS's shutdown command or on command, it may cause the battery pack to burn out or other faults. Therefore, after controlling the relay, BMS also detects whether the relay has normally executed the corresponding on command or off command, that is, detects whether the relay has a fault. In order to ensure that the BMS can identify the corresponding fault when a relay fails, the existing technology usually tests whether the BMS can normally detect the fault of the relay. If a DC power supply is used to simulate the battery pack output with the same output voltage as the battery pack, please refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of a test circuit for relay fault detection in the prior art. Figure 2 DC is the DC power supply, BAT+ is the positive output terminal of the DC power supply, which is connected to the first detection terminal of the BMS and the first terminal of the relay, and RLY+ is the second detection terminal of the BMS, which is connected to the second terminal of the relay. When testing whether the BMS can detect that the relay is not closed normally, please refer to Figure 3 , Figure 3 This is a schematic diagram of the test circuit structure of a relay fault detection when testing the relay closing fault detection of the BMS in the prior art. The second end of the relay is disconnected from the second detection end of the BMS to simulate the situation where the relay does not execute the closing instruction and is turned off. After the BMS outputs the relay closing instruction, if the BMS cannot detect the voltage at the second end of the relay and determines that the relay is not closed normally, it can be determined that the BMS can detect the fault of the relay not being able to close normally. When testing whether the BMS can detect that the relay is not turned off normally, please refer to Figure 4 , Figure 4 This is a schematic diagram of the test circuit structure for relay fault detection when testing the relay shutdown fault detection of the BMS in the prior art. The output positive terminal of the DC power supply is connected to the first terminal and the second terminal of the relay and the second detection terminal of the BMS. After the BMS outputs the relay shutdown command, if the BMS determines that the relay is not normally shut down because it detects that the voltage at the second terminal of the relay is consistent with the voltage at the first terminal, it can be determined that the BMS is able to detect the fault that the relay cannot be shut down normally.

[0054] However, it is not difficult to see that the above method can only determine whether the BMS can detect whether the relay is faulty, that is, it can only detect whether the relay has normally executed the corresponding closing instruction or closing instruction, but it cannot determine the triggering conditions for triggering the BMS to identify the relevant faults. For example, it cannot be determined how the BMS determines that the relay is faulty when it detects changes in the voltage across the relay. Therefore, it cannot be determined whether the BMS detects that the relay is faulty according to the set triggering conditions, that is, it cannot be determined the fault detection performance of the BMS.

[0055] In the present application, two power supplies are set in the test circuit, wherein the output voltage of the first power supply DC1 simulates the output voltage of the battery pack. For example, if the output voltage of the battery pack is 700V, then the output voltage of the first power supply DC1 is also 700V. If the output voltage of the battery pack is 600V, then the output voltage of the first power supply DC1 is 500V. The output voltage of the second power supply DC2 is not fixed, but first outputs a first preset voltage and then adjusts it. The first preset voltage is a voltage that is in a preset proportion to the output voltage of the first power supply DC1, that is, the first preset voltage changes with the change of the output voltage of the first power supply DC1. By adjusting the output voltage of the second power supply DC2, the voltage difference between the first detection end and the second detection end of the BMS is adjusted, and the change in the voltage between the first detection end and the second detection end of the BMS is used to simulate the change in the voltage at both ends of the relay.

[0056] The preset ratio is a pre-set trigger condition for the BMS to detect a relay fault. For example, if the preset ratio is 90%, then ideally, the BMS determines that the relay is in a closed state when it determines that the voltage of its second detection terminal is not less than 90% of the voltage of the first detection terminal, and determines that the relay is in an off state when it determines that the voltage of its second detection terminal is less than 90% of the voltage of the first detection terminal. However, due to the high complexity of the internal logic of the BMS, although the preset ratio is set to 90%, the actual preset ratio that triggers the BMS to detect an abnormality in the relay is not 90%. In this case, the BMS cannot detect whether the relay is faulty according to the set trigger condition.

[0057] The relay in this application is a normally functioning relay. Upon receiving a preset instruction, the relay operates normally according to the preset instruction. For example, if the preset instruction sent by the BMS is a relay-off instruction, the relay is off. If the preset instruction sent by the BMS is a relay-close instruction, the relay is closed. In actual applications, the first detection terminal of the BMS is connected to the first detection terminal of the relay, and the second detection terminal of the BMS is connected to the second detection terminal of the relay. After the BMS sends a corresponding instruction to the relay, it determines whether the relay has properly executed the preset instruction based on the voltage across the relay. The voltage across the relay is the voltage between the first and second detection terminals of the BMS. Since the second power supply DC2 is directly connected to the second detection terminal of the BMS or connected to the second detection terminal of the BMS through a relay, the voltage between the first and second detection terminals of the BMS simulates the voltage across the relay. When the second power supply DC2 outputs the first preset voltage, the BMS sends the preset instruction to the relay and determines that the relay is in a first preset state based on the voltage between its own first and second detection terminals. The first preset state can be the state corresponding to the preset instruction. For example, if the preset instruction is a relay-close instruction, the first preset state of the relay can be the closed state.

[0058] It should be noted that in this application, the change in the output voltage of the second power supply DC2 is used to simulate the change in the voltage at both ends of the relay due to the change in the state of the relay. For example, when the output voltage of the second power supply DC2 is 90% of the output voltage of the first power supply DC1, the output voltage of the first power supply DC1 and the output voltage of the second power supply DC2 simulate the voltage at both ends of the relay when it is in a closed state; when the output voltage of the second power supply DC2 is 89% of the output voltage of the first power supply DC1, the output voltage of the first power supply DC1 and the output voltage of the second power supply DC2 simulate the voltage at both ends of the relay when it is in an off state. Based on this, the voltage between the first detection end and the second detection end of the BMS is simulated and adjusted to trigger the BMS to recognize the corresponding fault of the simulated relay.

[0059] S12: If it is the first preset state, adjust the output voltage of the second power supply DC2 with a preset step size, and after the adjustment, determine whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay;

[0060] If the second power supply DC2 outputs the first preset voltage, and the BMS can determine that the relay is in the first preset state after sending the preset instruction to the relay, then the output voltage of the second power supply DC2 is adjusted with a preset step size, such as increasing or decreasing the output voltage of the second power supply DC2. After the output voltage of the second power supply DC2 is adjusted, it is necessary to determine whether the BMS determines that the relay is in the second preset state based on the voltage difference between its own first detection end and the second detection end after sending the preset instruction to the relay, that is, to determine whether the BMS can recognize the change in the state of the simulated relay, so as to determine whether the BMS can recognize that the relay has a fault.

[0061] S13: If it is the second preset state, determine that the fault triggering critical voltage of the BMS is the first preset voltage; the first preset state and the second preset state are the off state or the closed state, and the first preset state and the second preset state are different.

[0062] If the BMS can identify that the state of the relay has changed based on the voltage between its own first detection terminal and the second detection terminal before and after the output voltage of the second power supply DC2 is adjusted, then it can be determined that the fault trigger critical voltage that triggers the BMS to identify that the relay has failed is the first preset voltage corresponding to the set preset ratio. That is, the BMS can accurately identify that the relay has failed based on the set trigger condition based on the voltage between its own first detection terminal and the second detection terminal according to the set preset ratio, and the working performance of the BMS meets the expected requirements.

[0063] It should be noted that the preset ratio in the present application may be a percentage, and the preset step size may be, but is not limited to, 1% of the output voltage of the first power supply DC1.

[0064] It should also be noted that the first detection end of the BMS is connected to the positive output end of the first power supply DC1, and the ground end is connected to the negative output end of the first power supply DC1 and the negative output end HV_GND of the second power supply DC2; when the positive output end of the second power supply DC2 is connected to the first end of the relay, the second end of the relay is connected to the second detection end of the BMS; when the positive output end of the second power supply DC2 is connected to the second detection end of the BMS, the first end of the relay is connected to the positive output end of the first power supply DC1, and the second end of the relay is connected to the second detection end of the BMS.

[0065] In addition, the first power source and the second power source can be implemented by a battery pack, which is not limited in this application.

[0066] In summary, if the BMS determines that the relay is in the first preset state after outputting the preset instruction when the second power supply DC2 outputs the first preset voltage, and can determine that the state of the relay has changed when the BMS outputs the preset instruction again after adjusting the output voltage of the second power supply DC2 with a preset step size, then it can be determined that the fault trigger critical voltage that triggers the BMS to recognize that the relay has a fault is the first preset voltage, and then it is determined that the BMS detects that the relay has a fault according to the set preset ratio.

[0067] Based on the above embodiment:

[0068] As a preferred embodiment, the second power supply DC2 is connected to the second detection terminal of the BMS via a relay;

[0069] Controlling the second power supply DC2 to output a first preset voltage, and determining whether the BMS determines that the relay is in the first preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending a preset instruction to the relay, including:

[0070] Controlling the second power supply DC2 to output a first preset voltage, and determining whether the BMS determines that the relay is in a closed state based on the voltage difference between the first detection terminal and the second detection terminal after sending a closing instruction to the relay;

[0071] If it is the first preset state, adjusting the output voltage of the second power supply DC2 with a preset step size, and after the adjustment, determining whether the BMS determines that the relay is in the second preset state based on the voltage difference between its own first detection terminal and the second detection terminal after sending the preset instruction to the relay, including:

[0072] If it is in the closed state, the output voltage of the second power supply DC2 is reduced by a preset step size, and after adjustment, it is determined whether the BMS determines that the relay is in the closed state based on the voltage difference between its own first detection terminal and the second detection terminal after sending a closing instruction to the relay.

[0073] In this embodiment, the BMS is tested to see whether it can detect that the relay cannot normally execute the relay closing instruction. Taking a preset ratio of 90% as an example, the BMS is pre-set as follows: the first end of the relay and the first detection end of the BMS are both connected to the positive output end of the battery pack, and the second end of the relay is connected to the second detection end of the BMS. After the BMS sends a closing instruction to the relay, if the BMS detects that the voltage at the second end of the relay is greater than 90% of the voltage at the first end of the relay, then it is determined that the relay has normally executed the closing instruction and is in a closed state; and after the BMS sends a closing instruction to the relay, if the BMS detects that the voltage at the second end of the relay is not greater than 90% of the voltage at the first end of the relay, then it is determined that the relay has not normally executed the closing instruction and is in an off state, that is, there is a fault in the relay that cannot be closed normally.

[0074] Based on this, in this embodiment, the first end of the relay is connected to the output positive terminal of the second power supply DC2, and the second end of the relay is connected to the second detection terminal of the BMS. Figure 5 , Figure 5 The present application provides a schematic diagram of the test circuit structure for relay fault detection when testing the relay closing fault detection of the BMS. The second power supply DC2 first outputs a first preset voltage. After the BMS outputs a closing instruction, the relay can be closed normally. The second power supply DC2 is connected to the second detection end of the BMS through the relay. The first preset voltage output by the second power supply DC2 simulates the voltage of the second end of the relay, that is, the voltage of the second detection end of the BMS is the first preset voltage. The voltage of the second detection end of the BMS is in a preset ratio to the voltage of the first detection end. If the BMS can determine based on this that the relay has normally executed the closing instruction and is in a closed state, the output voltage of the second power supply DC2 can be reduced by a preset step size. After the BMS outputs the ... C2 is connected to the second detection end of the BMS through a relay. The output voltage of the second power supply DC2 after being reduced simulates the voltage of the second end of the relay, that is, the voltage of the second detection end of the BMS is the output voltage of the second power supply DC2 after being reduced. The ratio of the voltage of the second detection end of the BMS to the voltage of the first detection end is less than the preset ratio. If the BMS can determine based on this that the relay has not executed the closing instruction normally and is in the off state, that is, there is a fault in the relay that cannot be closed normally, then it can be determined that the BMS is indeed detecting whether there is a fault in the relay based on the preset ratio, that is, there is no deviation in the internal logic of the BMS, or the deviation is small, which is sufficient for the BMS to detect whether the relay is faulty based on the set trigger condition, and then it can be determined that the fault detection performance of the BMS is qualified.

[0075] Specifically, taking the preset ratio of 90% as an example, the BMS determines that the relay is in a closed state when the ratio between the voltage at its own second detection terminal and the voltage at the first detection terminal is not less than 90%. The BMS determines that the relay is in an off state when the ratio between the voltage at its own second detection terminal and the voltage at the first detection terminal is less than 90%. When the output voltage of the first power supply DC1 is 100V, the second power supply DC2 first outputs a voltage of 90V. After the BMS outputs a closing instruction, the relay can be closed normally. The second power supply DC2 is connected to the second detection terminal of the BMS through the relay. The 90V voltage output by the second power supply DC2 simulates the voltage at the second end of the relay, that is, the voltage at the second detection terminal of the BMS is 90V, and the ratio between the voltage at the second detection terminal of the BMS and the voltage at the first detection terminal is 90%. If the BMS can determine based on this that the relay has normally executed the closing instruction and is in a closed state state, the output voltage of the second power supply DC2 can be reduced to 89V. After the BMS outputs the closing command, the relay can be closed normally. The second power supply DC2 is connected to the second detection terminal of the BMS through the relay, and the voltage of the second terminal of the relay is simulated with a voltage of 89V, that is, the voltage of the second detection terminal of the BMS is 89V. The ratio of the voltage of the second detection terminal of the BMS to the voltage of the first detection terminal is 89%, which is less than 90%. If the BMS can determine based on this that the relay has not executed the closing command normally and is in the off state, that is, there is a fault in the relay that cannot be closed normally, then it can be determined that when the output voltage of the first power supply DC1 is 100V, the fault trigger critical voltage of the BMS is 90V, that is, the BMS does detect whether the relay has a fault based on the voltage of its own second detection terminal being 90% of the voltage of the first detection terminal as a trigger condition, which is consistent with the preset ratio.

[0076] Of course, the following examples are also possible:

[0077] Taking the preset ratio of 89% as an example, the BMS determines that the relay is in a closed state when the ratio between the voltage at its second detection terminal and the voltage at its first detection terminal is greater than 89%. The BMS determines that the relay is in an off state when the ratio between the voltage at its second detection terminal and the voltage at its first detection terminal is not greater than 89%. Taking the output voltage of the first power supply DC1 as 100V as an example, the second power supply DC2 first outputs a voltage of 89V. After the BMS outputs a closing instruction, the relay can be closed normally. The second power supply DC2 is connected to the second detection terminal of the BMS through the relay. The 89V voltage output by the second power supply DC2 simulates the voltage at the second end of the relay, that is, the voltage at the second detection terminal of the BMS is 89V, and the ratio between the voltage at the second detection terminal of the BMS and the voltage at the first detection terminal is 89%. If the BMS can determine based on this that the relay has not executed the closing instruction normally and is in an off state, that is, there is a fault in the relay that cannot be closed normally, then the output voltage of the second power supply DC2 can be increased to 90V, and the BMS outputs a closing instruction. After the command, the relay can be closed normally. The second power supply DC2 is connected to the second detection terminal of the BMS through the relay, and the voltage of the second terminal of the relay is simulated with a voltage of 90V. That is, the voltage of the second detection terminal of the BMS is 90V. The ratio of the voltage of the second detection terminal of the BMS to the voltage of the first detection terminal is 90%, which is greater than 89%. If the BMS can determine based on this that the relay has normally executed the closing command and is in the closed state, then it can be determined that when the output voltage of the first power supply DC1 is 100V, the fault triggering critical voltage of the BMS is 90V. That is, the BMS does detect whether there is a fault in the relay based on the trigger condition that the voltage of its second detection terminal is 90% of the voltage of the first detection terminal, which is consistent with the preset ratio. That is, in this application, whether the BMS can trigger and identify the change in the state of the relay before and after the first preset voltage adjustment is mainly used to determine whether the fault triggering critical voltage of the BMS is the first preset voltage, and then determine whether the actual triggering condition of the BMS is consistent with the set triggering condition.

[0078] As a preferred embodiment, the second power supply DC2 is directly connected to the second detection terminal of the BMS;

[0079] Controlling the second power supply DC2 to output a first preset voltage, and determining whether the BMS determines that the relay is in the first preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending a preset instruction to the relay, including:

[0080] Controlling the second power supply DC2 to output a first preset voltage, and determining whether the BMS determines that the relay is in the off state based on the voltage difference between the first detection terminal and the second detection terminal after sending a shutdown command to the relay;

[0081] If it is the first preset state, adjusting the output voltage of the second power supply DC2 with a preset step size, and after the adjustment, determining whether the BMS determines that the relay is in the second preset state based on the voltage difference between its own first detection terminal and the second detection terminal after sending the preset instruction to the relay, including:

[0082] If it is in the off state, the output voltage of the second power supply DC2 is increased by a preset step size, and after adjustment, it is determined whether the BMS determines that the relay is in the closed state based on the voltage difference between its own first detection terminal and the second detection terminal after sending a shutdown command to the relay.

[0083] In this embodiment, a test is performed to determine whether the BMS can detect that the relay cannot normally execute the relay shutdown instruction. Taking a preset ratio of 90% as an example, the BMS is pre-set as follows: the first end of the relay and the first detection end of the BMS are both connected to the positive output end of the battery pack, and the second end of the relay is connected to the second detection end of the BMS. After the BMS sends a shutdown instruction to the relay, if the BMS detects that the voltage of the second end of the relay is less than 90% of the voltage of the first end of the relay, then it is determined that the relay has normally executed the shutdown instruction and is in a closed state; and after the BMS sends a shutdown instruction to the relay, if the BMS detects that the voltage of the second end of the relay is not less than 90% of the voltage of the first end of the relay, then it is determined that the relay has not normally executed the shutdown instruction and is in a closed state or in a stuck state, that is, there is a fault in the relay that cannot be shut down normally.

[0084] Based on this, in this embodiment, the first end of the relay is connected to the output positive terminal of the first power supply DC1 and the first detection terminal of the BMS, and the second end of the relay is connected to the output positive terminal of the second power supply DC2 and the second detection terminal of the BMS. Please refer to Figure 6 , Figure 6This is a schematic diagram of the test circuit structure for relay fault detection when testing the relay shutdown fault detection of the BMS provided in the present application. The second power supply DC2 first outputs a first preset voltage. After the BMS outputs a shutdown command, the relay can be shut down normally. The second power supply DC2 is connected to the second detection end of the BMS through the relay. The first preset voltage output by the second power supply DC2 simulates the voltage of the second end of the relay, that is, the voltage of the second detection end of the BMS is the first preset voltage. The voltage of the second detection end of the BMS is in a preset ratio to the voltage of the first detection end. If the BMS can determine based on this that the relay has not executed the shutdown command normally and is in a closed state, that is, there is a fault in the relay that cannot be shut down normally, then the output voltage of the second power supply DC2 can be increased or decreased by a preset step size. After the BMS outputs the shutdown command, the relay can be shut down normally. The second power supply DC2 is connected to the second detection end of the BMS through a relay. The output voltage of the second power supply DC2 after being reduced simulates the voltage of the second end of the relay, that is, the voltage of the second detection end of the BMS is the output voltage of the second power supply DC2 after being reduced. The ratio of the voltage of the second detection end of the BMS to the voltage of the first detection end is less than the preset ratio. If the BMS can determine based on this that the relay has normally executed the shutdown instruction and is in the shutdown state, that is, there is no fault in the relay that cannot be shut down normally, then it can be determined that the BMS is indeed detecting whether there is a fault in the relay that cannot be shut down normally based on the preset ratio, that is, there is no deviation in the internal logic of the BMS, or the deviation is small, which is sufficient for the BMS to detect whether the relay is faulty based on the set trigger condition, and then it can be determined that the fault detection performance of the BMS is qualified.

[0085] Specifically, taking the preset ratio of 90% as an example, the BMS determines that the relay is in a closed state when the ratio between the voltage at its second detection terminal and the voltage at the first detection terminal is not less than 90%. The BMS determines that the relay is in an off state when the ratio between the voltage at its second detection terminal and the voltage at the first detection terminal is less than 90%. When the output voltage of the first power supply DC1 is 100V, the second power supply DC2 first outputs a voltage of 90V. After the BMS outputs the shutdown command, the relay can be shut down normally. The second power supply DC2 is connected to the second detection terminal of the BMS through the relay. The 90V voltage output by the second power supply DC2 simulates the voltage at the second end of the relay, that is, the voltage at the second detection terminal of the BMS is 90V, and the ratio between the voltage at the second detection terminal of the BMS and the voltage at the first detection terminal is 90%. If the BMS can determine based on this that the relay has not executed the shutdown command normally and is in a closed state, that is, the relay is unable to For a normal shutdown fault, the output voltage of the second power supply DC2 can be reduced to 89V. After the BMS outputs the shutdown command, the relay can be shut down normally. The second power supply DC2 is connected to the second detection terminal of the BMS through the relay. The 89V voltage output by the second power supply DC2 simulates the voltage of the second end of the relay, that is, the voltage of the second detection terminal of the BMS is 89V. The ratio of the voltage of the second detection terminal of the BMS to the voltage of the first detection terminal is 89%, which is less than 90%. If the BMS can determine based on this that the relay has normally executed the shutdown command and is in the shutdown state, that is, there is no fault that the relay cannot be shut down normally, then it can be determined that when the output voltage of the first power supply DC1 is 100V, the fault trigger critical voltage of the BMS is 90V, that is, the BMS does detect whether the relay has a fault based on the voltage of its own second detection terminal being 90% of the voltage of the first detection terminal as a trigger condition, which is consistent with the preset ratio.

[0086] Of course, the following examples are also possible:

[0087] Taking the preset ratio of 89% as an example, the BMS determines that the relay is in a closed state when the ratio between the voltage at its second detection terminal and the voltage at its first detection terminal is greater than 89%. The BMS determines that the relay is in an off state when the ratio between the voltage at its second detection terminal and the voltage at its first detection terminal is not greater than 89%. Taking the output voltage of the first power supply DC1 as 100V as an example, the second power supply DC2 first outputs a voltage of 89V. After the BMS outputs a shutdown command, the relay can be shut down normally. The second power supply DC2 is connected to the second detection terminal of the BMS through the relay. The 89V voltage output by the second power supply DC2 simulates the voltage at the second end of the relay, that is, the voltage at the second detection terminal of the BMS is 89V, and the ratio between the voltage at the second detection terminal of the BMS and the voltage at the first detection terminal is 89%. If the BMS can determine based on this that the relay has normally executed the shutdown command and is in the off state, then it can Increase the output voltage of the second power supply DC2 to 90V. After the BMS outputs the shutdown command, the relay can be shut down normally. The second power supply DC2 is connected to the second detection end of the BMS through the relay. The 90V voltage output by the second power supply DC2 simulates the voltage of the second end of the relay, that is, the voltage of the second detection end of the BMS is 90V. The ratio of the voltage of the second detection end of the BMS to the voltage of the first detection end is 90%, which is greater than 89%. If the BMS can determine based on this that the relay has not executed the shutdown command normally and is in a closed state, that is, there is a fault in the relay that cannot be shut down normally, then it can be determined that when the output voltage of the first power supply DC1 is 100V, the fault trigger critical voltage of the BMS is 90V, that is, the BMS does detect whether the relay has a fault based on the voltage of its own second detection end being 90% of the voltage of the first detection end as a trigger condition, which is consistent with the preset ratio.

[0088] It should be noted that a first switching switch can be set between the first end of the relay and the positive output terminal of the first power supply DC1, that is, the first detection terminal of the BMS, a second switching switch can be set between the first end of the relay and the positive output terminal of the second power supply DC2, and a third switching switch can be set between the second end of the relay and the positive output terminal of the second power supply DC2; when the relay closing fault detection of the BMS is tested, the first switching switch is turned off, the second switching switch is closed, and the third switching switch is turned off; when the relay closing fault detection of the BMS is tested, the first switching switch is closed, the second switching switch is turned off, and the third switching switch is closed.

[0089] As a preferred embodiment, before controlling the second power supply DC2 to output the first preset voltage, the method further includes:

[0090] Determining the output voltage of the first power supply DC1;

[0091] The first preset voltage is calculated based on a product of the output voltage and a preset ratio.

[0092] In this embodiment, when determining the first preset voltage output by the second power supply DC2, the output voltage of the first power supply DC1 can be directly multiplied by the preset ratio to calculate the first preset voltage, or the output voltage of the first power supply DC1 can be multiplied by a value less than the preset ratio or greater than the preset ratio to calculate the first preset voltage, which shall be based on actual needs.

[0093] For example, the preset ratio is 90%. When the ratio between the voltage at the second detection terminal and the voltage at the first detection terminal of the BMS is not less than 90%, the BMS determines that the relay is in a closed state. When the ratio between the voltage at the second detection terminal and the voltage at the first detection terminal of the BMS is less than 90%, the BMS determines that the relay is in a closed state. When the output voltage of the first power supply DC1 is 100V, the first preset voltage can be calculated to be 90V. When the voltage at the second detection terminal of the BMS is not less than 90V, the BMS determines that the relay is in a closed state. When the voltage at the second detection terminal of the BMS is less than 90V, the BMS determines that the relay is in a closed state. The preset ratio is 89%. When the ratio between the voltage at the second detection terminal of the BMS and the voltage at the first detection terminal is greater than 89%, the BMS determines that the relay is in a closed state. When the ratio between the voltage at the second detection terminal of the BMS and the voltage at the first detection terminal is not greater than 89%, the BMS determines that the relay is in an off state. When the output voltage of the first power supply DC1 is 100V, the first preset voltage can be calculated to be 89V. The BMS determines that the relay is in a closed state when the voltage at the second detection terminal of the BMS is greater than 89V. When the voltage at the second detection terminal of the BMS is not greater than 89V, the BMS determines that the relay is in an off state.

[0094] As a preferred embodiment, if the state is the first preset state, the output voltage of the second power supply DC2 is adjusted with a preset step size, and after the adjustment, it is determined whether the BMS determines that the relay is in the second preset state based on the voltage difference between its own first detection terminal and the second detection terminal after sending the preset instruction to the relay, and further includes:

[0095] If it is not the second preset state, it is determined that the fault of the BMS triggers an abnormal threshold voltage setting.

[0096] In this embodiment, if after the output voltage of the second power supply DC2 is adjusted, the BMS does not detect a change in the state of the relay after sending a preset instruction to the relay compared to the state of the relay before the output voltage of the second power supply DC2 is adjusted, then it can be determined that the fault trigger critical voltage setting of the BMS is abnormal, that is, the BMS cannot perform fault detection according to the preset ratio, and there may be a deviation in the internal logic of the BMS, and the BMS needs to be troubleshooted or the preset ratio needs to be re-set.

[0097] It should be noted that when a preset ratio is set for the BMS, it is expected that the BMS can determine that the relay is in a closed state when the ratio between the voltage at its own second detection terminal and the voltage at the first detection terminal is not less than the preset ratio, and determine that the relay is in an off state when the ratio between the voltage at its own second detection terminal and the voltage at the first detection terminal is less than the preset ratio. However, if the BMS cannot judge the state of the relay according to the set preset ratio, it may cause deviation in the judgment of the state of the relay, and thus cause irreparable damage to the circuit.

[0098] If the preset ratio set for the BMS is 90%, it is expected that the BMS can determine that the relay is in a closed state when the ratio between the voltage at its own second detection terminal and the voltage at the first detection terminal is not less than 90%, and determine that the relay is in an off state when the ratio between the voltage at its own second detection terminal and the voltage at the first detection terminal is less than 90%. However, if in actual circumstances the ratio between the voltage at its second detection terminal and the voltage at the first detection terminal is less than 90% after the BMS outputs the relay closing command, that is, the actual situation is that the relay does not execute the closing command normally and is in an off state, but the internal logic of the BMS believes that the ratio between the voltage at the second detection terminal and the voltage at the first detection terminal of the BMS is still not less than 90% and determines that the relay is in a closed state. If the relay is in the closed state, the BMS fails to detect the fault that the relay cannot be closed normally in time, or if the ratio between the voltage at the second detection terminal and the voltage at the first detection terminal is not less than 90% after the BMS outputs the relay shutdown command in actual situation, that is, the actual situation is that the relay does not execute the shutdown command normally and is in the closed state, but the internal logic of the BMS believes that the ratio between the voltage at the second detection terminal and the voltage at the first detection terminal of the BMS is still less than 90% and determines that the relay is in the closed state, then the BMS fails to detect the fault that the relay cannot be closed normally in time, resulting in the inability to perform subsequent work normally, that is, the BMS cannot judge the state of the relay according to the set preset ratio, which leads to irreparable damage in the circuit.

[0099] Based on this, the present application can verify whether the BMS is able to detect whether a relay failure occurs according to a set preset ratio, so as to determine the accuracy and validity of the BMS's relay fault detection results.

[0100] As a preferred embodiment, after determining that the BMS fault triggers an abnormal critical voltage setting, the method further includes:

[0101] The preset ratio setting parameter of the BMS is adjusted until the fault triggering critical voltage of the BMS reaches a first preset voltage.

[0102] In this embodiment, when it is determined that the fault triggering critical voltage setting of the BMS is abnormal, that is, the BMS cannot accurately perform relay fault detection according to the set preset ratio, the BMS preset ratio setting parameters can be adjusted.

[0103] For example, if the preset ratio set for the BMS is 90%, it is expected that the BMS will be able to determine that the relay is in a closed state when the ratio between the voltage at its own second detection terminal and the voltage at its own first detection terminal is not less than 90%, and determine that the relay is in a closed state when the ratio between the voltage at its own second detection terminal and the voltage at its own first detection terminal is less than 90%. However, through the above test, it is determined that the internal logic of the BMS is to determine that the relay is in a closed state when the ratio between the voltage at its own second detection terminal and the voltage at its own first detection terminal is not less than 89%, and determine that the relay is in a closed state when the ratio between the voltage at its own second detection terminal and the voltage at its own first detection terminal is less than 89%. state, then after adjusting the preset ratio setting parameters of the BMS, it is expected that the BMS can determine that the relay is in a closed state when the ratio between the voltage of its own second detection terminal and the voltage of the first detection terminal is not less than 91%, and determine that the relay is in an off state when the ratio between the voltage of its own second detection terminal and the voltage of the first detection terminal is less than 91%, so as to actually cause the internal logic of the BMS to determine that the relay is in a closed state when the ratio between the voltage of its own second detection terminal and the voltage of the first detection terminal is not less than 90%, and determine that the relay is in an off state when the ratio between the voltage of its own second detection terminal and the voltage of the first detection terminal is less than 90%.

[0104] Of course, the specific method of adjusting the preset ratio setting parameters of the BMS is not limited in this application, as long as the fault triggering critical voltage of the BMS is set to the first preset voltage, that is, the actual response of the BMS is to perform relay fault detection based on the preset ratio.

[0105] Please refer to Figure 7 , Figure 7 This is a schematic diagram of the structure of a test system for relay fault detection provided by the present application, which includes a test circuit for relay fault detection. The test circuit includes a first power supply DC1 and a second power supply DC2. The first power supply DC1 is connected to a first detection terminal of a BMS, the second power supply DC2 is connected to a second detection terminal of the BMS directly or through a relay, and the control terminal of the BMS is connected to the control terminal of the relay.

[0106] The test system includes:

[0107] a control unit 71 for controlling the second power source DC2 to output a first preset voltage and determining whether, after the BMS sends a preset instruction to the relay, the relay is in the first preset state based on the voltage difference between the first detection terminal and the second detection terminal of the BMS; the first preset voltage is in a preset ratio to the output voltage of the first power source DC1;

[0108] a determination unit 72 for adjusting the output voltage of the second power source DC2 by a preset step size if the state is the first preset state, and after the adjustment, determining whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay;

[0109] The determination unit 73 is configured to determine that the fault triggering critical voltage of the BMS is the first preset voltage if the second preset state is in the second preset state; the first preset state and the second preset state are the off state or the closed state, and the first preset state and the second preset state are different.

[0110] For an introduction to the test system for relay fault detection provided by the present invention, please refer to the above method embodiment, and the present invention will not be described in detail here.

[0111] Please refer to Figure 8 , Figure 8 This is a schematic diagram of the structure of a test device for relay fault detection provided by the present application, the device comprising:

[0112] Memory 81, for storing computer programs;

[0113] The processor 82 is configured to implement the steps of the above-mentioned relay fault detection test method when executing the computer program.

[0114] For an introduction to the test device for relay fault detection provided by the present invention, please refer to the above method embodiment, and the present invention will not be described in detail here.

[0115] To solve the above technical problems, the present invention provides a test circuit for relay fault detection, including the test device for relay fault detection as described above, and also including a first power supply DC1 and a second power supply DC2, the first power supply DC1 is connected to the first detection end of the BMS, the second power supply DC2 is directly connected to the second detection end of the BMS or connected to the second detection end of the BMS through a relay, and the control end of the BMS is connected to the control end of the relay.

[0116] For an introduction to the test circuit for relay fault detection provided by the present invention, please refer to the above method embodiment, and the present invention will not elaborate on it here.

[0117] Please refer to Figure 9 , Figure 9This is a structural diagram of a computer-readable storage medium provided in the present application. A computer program 92 is stored on the computer-readable storage medium 91. When the computer program 92 is executed by the processor 82, the steps of the test method for relay fault detection as described above are implemented.

[0118] For an introduction to the computer-readable storage medium 91 provided by the present invention, please refer to the above method embodiment, and the present invention will not elaborate on it here.

[0119] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover 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 additional identical elements in the process, method, article, or apparatus comprising the element.

[0120] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A test method for relay fault detection, characterized in that: A test circuit for relay fault detection, the test circuit comprising a first power supply and a second power supply; the first power supply is connected to a first detection terminal of a BMS, the second power supply is connected to a second detection terminal of the BMS directly or through a relay, and a control terminal of the BMS is connected to a control terminal of the relay; The test method includes: controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in a first preset state based on a voltage difference between the first detection terminal and the second detection terminal of the BMS after sending a preset instruction to the relay; the first preset voltage is in a preset ratio to the output voltage of the first power supply; If it is the first preset state, adjusting the output voltage of the second power supply with a preset step size, and after the adjustment, determining whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay; If it is the second preset state, it is determined that the fault trigger critical voltage of the BMS is the first preset voltage; the first preset state and the second preset state are the off state or the closed state, and the first preset state and the second preset state are different.

2. The test method for relay fault detection according to claim 1, wherein: The second power supply is connected to the second detection terminal of the BMS through the relay; Controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in the first preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending a preset instruction to the relay, including: controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in a closed state based on a voltage difference between the first detection terminal and the second detection terminal of the BMS after sending a closing instruction to the relay; If the relay is in the first preset state, adjusting the output voltage of the second power supply with a preset step size, and determining after the adjustment whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay, including: If it is the closed state, the output voltage of the second power supply is reduced by a preset step size, and after adjustment, it is determined whether the BMS determines that the relay is in the off state based on the voltage difference between its own first detection terminal and the second detection terminal after sending the closing instruction to the relay.

3. The test method for relay fault detection according to claim 1, wherein: The second power supply is directly connected to the second detection terminal of the BMS; Controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in the first preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending a preset instruction to the relay, including: controlling the second power supply to output a first preset voltage, and determining whether the BMS determines that the relay is in an off state based on a voltage difference between the first detection terminal and the second detection terminal of the BMS after sending a shut-down command to the relay; If the relay is in the first preset state, adjusting the output voltage of the second power supply with a preset step size, and determining after the adjustment whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay, including: If it is the shutdown state, the output voltage of the second power supply is increased by a preset step size, and after adjustment, it is determined whether the BMS determines that the relay is in the closed state based on the voltage difference between its own first detection terminal and the second detection terminal after sending the shutdown instruction to the relay.

4. The test method for relay fault detection according to claim 1, wherein: Before controlling the second power supply to output the first preset voltage, the method further includes: determining an output voltage of the first power supply; The first preset voltage is calculated based on a product of the output voltage and the preset ratio.

5. The test method for relay fault detection according to any one of claims 1 to 4, characterized in that: If the relay is in the first preset state, the output voltage of the second power supply is adjusted with a preset step size, and after the adjustment, it is determined whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal after sending the preset instruction to the relay, further comprising: If it is not the second preset state, it is determined that the fault triggering critical voltage setting of the BMS is abnormal.

6. The test method for relay fault detection according to claim 5, wherein: After determining that the fault triggering critical voltage setting of the BMS is abnormal, the method further includes: The preset ratio setting parameter of the BMS is adjusted until the fault triggering critical voltage of the BMS reaches the first preset voltage.

7. A test system for relay fault detection, characterized in that: A test circuit for relay fault detection, the test circuit comprising a first power supply and a second power supply, the first power supply being connected to a first detection terminal of a BMS, the second power supply being connected to a second detection terminal of the BMS directly or through a relay, and the control terminal of the BMS being connected to the control terminal of the relay; The test system comprises: a control unit, configured to control the second power supply to output a first preset voltage, and determine whether the BMS determines that the relay is in a first preset state based on a voltage difference between the first detection terminal and the second detection terminal of the BMS after sending a preset instruction to the relay; the first preset voltage is in a preset ratio to the output voltage of the first power supply; a determining unit, configured to adjust the output voltage of the second power supply by a preset step size if the state is the first preset state, and after the adjustment, determine whether the BMS determines that the relay is in the second preset state based on the voltage difference between the first detection terminal and the second detection terminal of the BMS after sending the preset instruction to the relay; A determining unit is configured to determine that, if the second preset state is in effect, the fault triggering critical voltage of the BMS is the first preset voltage; the first preset state and the second preset state are an off state or a closed state, and the first preset state and the second preset state are different.

8. A test device for relay fault detection, characterized in that: include: memory for storing computer programs; A processor is configured to implement the steps of the relay fault detection test method according to any one of claims 1 to 6 when executing a computer program.

9. A test circuit for relay fault detection, characterized in that: The test device for relay fault detection as claimed in claim 8 further includes a first power supply and a second power supply, the first power supply is connected to the first detection terminal of the BMS, the second power supply is directly connected to the second detection terminal of the BMS or is connected to the second detection terminal of the BMS through a relay, and the control terminal of the BMS is connected to the control terminal of the relay.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the test method for relay fault detection according to any one of claims 1 to 6 are implemented.

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