Control detection method of BMS relay

Abstract

The invention relates to a control detection method for a BMS relay, and the method comprises the steps: carrying out the opening and closing control of a relay in a power battery management system according to a charging mode time sequence if the relay is in a charging mode, and carrying out the detection of the state of the relay according to an electric power parameter in the opening and closing control process, whether a relay in the power battery management system breaks down or not is judged; if the power battery management system is in the running mode, opening and closing control is conducted on a relay according to the running mode time sequence, and in the opening and closing control process, relay state detection is conducted according to electric power parameters in the power battery management system so as to judge whether the relay in the power battery management system breaks down or not. According to the invention, the relay can be disconnected in time when a vehicle or a power battery has a serious fault, the service life of the power battery is ensured, and the relay can be identified and reported under different working conditions when the relay has a fault.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicles, and in particular to a control and detection method for a BMS relay. Background Art

[0002] New energy vehicles are gradually transitioning from research and development to mass production, which puts forward higher requirements for the rational use of various components and timely detection of faults. New energy vehicles mainly include pure electric vehicles and hybrid vehicles. Regardless of the type of vehicle, power batteries are required as energy storage devices for kinetic energy recovery and energy optimization. The relay of the power battery is different from the relay used in traditional vehicles. It has the characteristics of high carrying voltage, large current load, and complex control logic. Therefore, it is particularly important to reasonably control the opening and closing of the relay and detect the fault state of the relay.

[0003] The switching state and fault diagnosis of relays involve the high-voltage electrical safety of automobiles, but relays with feedback have poor reliability and often misreport faults. Therefore, most domestic companies now use high-voltage relays without feedback. In terms of high-voltage battery control, companies have conducted a lot of research on power battery management systems, but there has been no in-depth research on the control and fault detection of relays without state feedback. Summary of the invention

[0004] The present invention provides a control and detection method for a BMS relay to solve at least one of the above technical problems.

[0005] The technical solution of the present invention to solve the above technical problem is as follows: A control detection method for a BMS relay, comprising:

[0006] Determine the vehicle mode of the new energy vehicle, wherein the vehicle mode includes a charging mode and a driving mode;

[0007] If the new energy vehicle is in the charging mode, the relay in the power battery management system of the new energy vehicle is opened and closed according to the charging mode timing sequence, and during the opening and closing control process, the relay state detection is performed according to the power parameters in the power battery management system to determine whether the relay in the power battery management system is faulty;

[0008] If the new energy vehicle is in the driving mode, the relay in the power battery management system of the new energy vehicle is opened and closed according to the driving mode timing, and during the opening and closing control process, the relay state is detected according to the power parameters in the power battery management system to determine whether the relay in the power battery management system is faulty.

[0009] Based on the above technical solution, the present invention can also be improved as follows.

[0010] Furthermore, the power battery management system includes:

[0011] Power battery;

[0012] A total positive relay, one contact of which is connected to the positive electrode of the power battery;

[0013] A total negative relay, one contact of which is connected to the negative electrode of the power battery;

[0014] A load, one end of which is connected to the other contact of the total positive relay, and the other end of which is connected to the other contact of the total negative relay;

[0015] A pre-charging relay, one contact of which is connected to one contact of the total positive relay, and the other contact of which is connected to the other contact of the total positive relay via a pre-charging resistor;

[0016] A first voltage detection device, two ends of which are respectively connected to the positive electrode and the negative electrode of the power battery;

[0017] A second voltage detection device, one end of which is connected to another contact of the total positive relay, and the other end of which is connected to another contact of the total negative relay;

[0018] Among them, the total positive relay, the total negative relay and the pre-charging relay are relays in the power battery management system.

[0019] Further, the relay in the power battery management system of the new energy vehicle is opened and closed and the status is detected according to the charging mode timing sequence:

[0020] S101, controlling the pre-charging relay to close, and executing S102;

[0021] S102, read the voltage detection value of the second voltage detection device, and determine whether the voltage detection value of the second voltage detection device decreases or remains unchanged; if not, it is determined that the total negative relay has a adhesion fault and reports it; if so, the total negative relay is controlled to close, and S103 is executed;

[0022] S103, reading the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device, and determining whether the absolute value of the difference between the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device is less than a first preset voltage threshold; if not, executing S104; if yes, executing S105;

[0023] S104, control the pre-charging relay to open, add 1 to the pre-charging times, and determine whether the pre-charging times are less than the first preset times; if so, control the pre-charging relay to close, and return to loop to execute S103; if not, determine that the total negative relay or the pre-charging relay fails to close or the power battery management system has a load failure;

[0024] S105, first control the total positive relay to close, then control the pre-charge relay to open, and execute S106;

[0025] S106, read the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device, and determine whether the difference between the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device is greater than a second preset voltage threshold; if not, determine that the power battery management system has no fault and maintain normal charging mode; if so, determine that the total positive relay has a failure to close and report it.

[0026] Further, in the S102, the S103 is executed after the total negative relay is controlled to be closed for a first preset time interval;

[0027] In S105, the pre-charging relay is controlled to open after a second preset time interval after the total positive relay is controlled to close.

[0028] Further, in S104, determining whether the total negative relay or the pre-charging relay fails to close or whether the power battery management system has a load failure is specifically as follows:

[0029] If the voltage detection value of the second voltage detection device does not rise when both the total negative relay and the pre-filling relay are closed, it is determined that the total negative relay or the pre-filling relay has a failure to close and is reported;

[0030] If the voltage detection value of the second voltage detection device rises when the total negative relay and the pre-charging relay are both closed, but cannot rise to meet the first preset condition within the third preset time, it is determined that a load fault occurs in the power battery management system and is reported.

[0031] Further, the relay in the power battery management system of the new energy vehicle is opened and closed and the status is detected according to the driving mode sequence:

[0032] S201, controlling the total negative relay to close, and executing S202;

[0033] S202, read the voltage detection value of the second voltage detection device, and determine whether the voltage detection value of the second voltage detection device decreases or remains unchanged; if not, it is determined that the pre-charge relay has a adhesion fault and reports it; if so, execute S203;

[0034] S203, controlling the pre-charging relay to close, reading the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device, and determining whether the absolute value of the difference between the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device is less than a third preset voltage threshold; if not, executing S204; if yes, executing S205;

[0035] S204, control the pre-charging relay to open, add 1 to the pre-charging times, and determine whether the pre-charging times are less than the second preset times; if so, return to loop and execute S203; if not, determine that the total negative relay or the pre-charging relay has a failure to close or the power battery management system has a load failure;

[0036] S205, first control the total positive relay to close, then control the pre-charge relay to open, and execute S206;

[0037] S206, read the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device, and determine whether the difference between the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device is greater than a fourth preset voltage threshold; if not, determine that the power battery management system has no fault and maintain normal driving mode; if so, determine that the total positive relay has a failure to close and report it.

[0038] Further, in the S203, the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device are read at a fourth preset time interval after the pre-charging relay is closed;

[0039] In S205, the pre-charging relay is controlled to open after a fifth preset time interval after the total positive relay is controlled to close.

[0040] Further, in S204, determining whether the total negative relay or the pre-charging relay fails to close or whether the power battery management system has a load failure is specifically as follows:

[0041] If the voltage detection value of the second voltage detection device does not rise when both the total negative relay and the pre-filling relay are closed, it is determined that the total negative relay or the pre-filling relay has a failure to close and is reported;

[0042] If the voltage detection value of the second voltage detection device rises when the total negative relay and the pre-charging relay are both closed, but cannot rise to meet the second preset condition within the sixth preset time, it is determined that a load fault occurs in the power battery management system and is reported.

[0043] Furthermore, in the process of opening and closing control and status detection of the relays in the power battery management system according to the charging mode sequence or the driving mode sequence, if a power-off command is received, the relays in the power battery management system are opened and closed and the status detection is performed according to the power-off mode sequence.

[0044] Furthermore, the opening and closing control and status detection of the relays in the power battery management system are specifically as follows according to the power-off mode timing sequence:

[0045] Determine a power-off mode in the power-off instruction; the power-off mode includes an emergency power-off mode and a normal power-off mode;

[0046] If the power-off mode is the emergency power-off mode, controlling the total positive relay and the total negative relay to open;

[0047] If the power-off mode is the normal power-off mode, the total negative relay is controlled to open, and the voltage detection value of the second voltage detection device is read, and it is determined whether the voltage detection value of the second voltage detection device decreases; if so, the total positive relay is controlled to open; if not, it is determined that the total positive relay has a adhesion fault and reported, and the total positive relay is controlled to open at an interval of the seventh preset time.

[0048] The beneficial effects of the present invention are as follows: a control and detection method for a BMS relay of the present invention selects a corresponding timing according to the whole vehicle mode of a new energy vehicle to control the opening and closing of a relay in a power battery management system, and detects the state of the relay according to the power parameters in the battery management system to determine whether the relay fails; the application of the present invention can disconnect the relay in time when a serious fault occurs in the vehicle or the power battery, thereby ensuring the service life of the power battery, and when the relay itself fails, it can identify and report it under different working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A flowchart of a control and detection method for a BMS relay of the present invention;

[0050] Figure 2 A flow chart of a control and detection method for a BMS relay according to the present invention;

[0051] Figure 3 It is a schematic diagram of the circuit structure of a typical existing power battery management system;

[0052] Figure 4 A flow chart for controlling the opening and closing of the relay and detecting the status according to the charging mode timing;

[0053] Figure 5 Flow chart for controlling the opening and closing of relays and detecting their status according to the driving mode sequence

[0054] Figure 6 The flowchart is for controlling the opening and closing of the relay and detecting the status according to the power-off mode timing. DETAILED DESCRIPTION

[0055] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0056] like Figure 1 As shown, a control detection method for a BMS relay includes:

[0057] Determine the vehicle mode of the new energy vehicle, wherein the vehicle mode includes a charging mode and a driving mode;

[0058] If the new energy vehicle is in the charging mode, the relay in the power battery management system of the new energy vehicle is opened and closed according to the charging mode timing sequence, and during the opening and closing control process, the relay state detection is performed according to the power parameters in the power battery management system to determine whether the relay in the power battery management system is faulty;

[0059] If the new energy vehicle is in the driving mode, the relay in the power battery management system of the new energy vehicle is opened and closed according to the driving mode timing, and during the opening and closing control process, the relay state is detected according to the power parameters in the power battery management system to determine whether the relay in the power battery management system is faulty.

[0060] Specifically, Figure 2 As shown, when judging the vehicle mode of a new energy vehicle, it is determined whether the new energy vehicle is in a charging mode or a driving mode. First, it can be determined whether it is in a charging mode. If it is not in a charging mode, the driving mode timing control is performed on the relay in the power battery management system, and when the driving mode timing control is performed, the relay is judged to be faulty and the fault type is reported according to the power parameters in the power battery management system; if it is in a charging mode, the charging mode timing control is performed on the relay in the power battery management system, and when the charging mode timing control is performed, the relay is judged to be faulty and the fault type is reported according to the power parameters in the power battery management system; wherein, the fault type includes relay adhesion or failure to be attracted.

[0061] In some embodiments, Figure 3 As shown, the power battery management system includes:

[0062] Power battery E;

[0063] A total positive relay J1, one contact of which is connected to the positive electrode of the power battery E;

[0064] A total negative relay J2, one contact of which is connected to the negative electrode of the power battery E;

[0065] A load M, one end of which is connected to another contact of the total positive relay J1, and the other end of which is connected to another contact of the total negative relay J2;

[0066] A pre-charging relay J3, one contact of which is connected to one contact of the total positive relay J1, and another contact of which is connected to another contact of the total positive relay J1 through a pre-charging resistor R;

[0067] A first voltage detection device V1, two ends of which are respectively connected to the positive electrode and the negative electrode of the power battery E;

[0068] A second voltage detection device V2, one end of which is connected to another contact of the total positive relay J1, and the other end of which is connected to another contact of the total negative relay J2;

[0069] Among them, the total positive relay J1, the total negative relay J2 and the pre-charging relay J3 are relays in the power battery management system.

[0070] Specifically, Figure 3 The table shows a main circuit architecture of a power battery for a new energy vehicle, which is representative in the industry. The present invention is designed based on this circuit architecture. Figure 3 As shown, the pre-charge relay J3 is connected in series with the pre-charge resistor, and then in parallel with the total positive relay J1, and connected to the positive electrode of the power battery E; the total negative relay J2 is connected to the negative electrode of the power battery E; the first voltage measuring device measures the voltage across the power battery E; the second voltage measuring device measures the voltage between the total positive relay J1 and the total negative relay J2; the power battery E outputs an external voltage of Vout, and the value range depends on the battery design value and the current battery state. The load M is connected between Vout, wherein the load M related to the present invention is a motor controller M, and the internal circuit of the motor controller M contains a capacitor of about 1 microfarad.

[0071] like Figure 4 As shown, the opening and closing control and status detection of the relay in the power battery management system of the new energy vehicle according to the charging mode timing are specifically as follows:

[0072] S101, controlling the pre-charging relay J3 to close, and executing S102;

[0073] S102, read the voltage detection value of the second voltage detection device V2, and determine whether the voltage detection value of the second voltage detection device V2 decreases or remains unchanged; if not, it is determined that the total negative relay J2 has a adhesion fault and reports it; if so, the total negative relay J2 is controlled to close, and S103 is executed;

[0074] S103, reading the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2, and determining whether the absolute value of the difference between the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2 (|V1-V2|) is less than a first preset voltage threshold (e.g., 40V); if not, executing S104; if yes, executing S105;

[0075] S104, control the pre-charging relay J3 to open, add 1 to the pre-charging times, and determine whether the pre-charging times are less than a first preset number (e.g., 3 times); if so, control the pre-charging relay J3 to close, and return to loop to execute S103; if not, determine that the total negative relay J2 or the pre-charging relay J3 fails to close or the power battery management system has a load failure;

[0076] S105, first control the total positive relay J1 to close, then control the pre-charge relay J3 to open, and execute S106;

[0077] S106, read the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2, and determine whether the difference (V1-V2) between the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2 is greater than a second preset voltage threshold (for example, 20V); if not, determine that the power battery management system has no fault and maintain normal charging mode; if so, determine that the total positive relay J1 has a failure to close and report it.

[0078] in,

[0079] In S102, the total negative relay J2 is controlled to be closed and then S103 is executed after a first preset time (for example, 0.1 second) has passed; in S105, the pre-charging relay J3 is controlled to be opened after a second preset time (for example, 0.5 second) has passed after the total positive relay J1 is controlled to be closed.

[0080] In S104, determining whether the total negative relay J2 or the pre-charge relay J3 fails to close or whether the power battery management system has a load failure is specifically as follows:

[0081] If the voltage detection value of the second voltage detection device V2 does not rise when both the total negative relay J2 and the pre-filling relay J3 are closed, it is determined that the total negative relay J2 or the pre-filling relay J3 has a failure to close and is reported;

[0082] If the voltage detection value of the second voltage detection device V2 rises when the total negative relay J2 and the pre-charge relay J3 are both closed, but cannot rise to meet the first preset condition within a third preset time (for example, 0.1 seconds), it is determined that a load fault occurs in the power battery management system and is reported.

[0083] like Figure 5 As shown, the opening and closing control and status detection of the relay in the power battery management system of the new energy vehicle according to the driving mode timing are specifically as follows:

[0084] S201, controlling the total negative relay J2 to close, and executing S202;

[0085] S202, read the voltage detection value of the second voltage detection device V2, and determine whether the voltage detection value of the second voltage detection device V2 decreases or remains unchanged; if not, it is determined that the pre-charge relay J3 has a adhesion fault and reports it; if so, execute S203;

[0086] S203, controlling the pre-charging relay J3 to close, reading the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2, and determining whether the absolute value of the difference between the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2 (|V1-V2|) is less than a third preset voltage threshold (e.g., 40V); if not, executing S204; if yes, executing S205;

[0087] S204, control the pre-charging relay J3 to open, add 1 to the pre-charging times, and determine whether the pre-charging times are less than a second preset number (e.g., 3 times); if so, return to loop and execute S203; if not, determine that the total negative relay J2 or the pre-charging relay J3 has a failure to close or the power battery management system has a load failure;

[0088] S205, first control the total positive relay J1 to close, then control the pre-charge relay J3 to open, and execute S206;

[0089] S206, read the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2, and determine whether the difference (V1-V2) between the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2 is greater than a fourth preset voltage threshold (for example, 20V); if not, determine that the power battery management system has no fault and maintain the normal driving mode; if so, determine that the total positive relay J1 has a failure to close and report it.

[0090] Among them, in S203, the voltage detection value of the first voltage detection device V1 and the voltage detection value of the second voltage detection device V2 are read at an interval of a fourth preset time (for example, 0.1 second) after the pre-charging relay J3 is controlled to be closed; in S205, the pre-charging relay J3 is controlled to be opened at an interval of a fifth preset time (for example, 0.5 second) after the total positive relay J1 is controlled to be closed.

[0091] In S204, determining whether the total negative relay J2 or the pre-charge relay J3 fails to close or whether the power battery management system has a load failure is specifically as follows:

[0092] If the voltage detection value of the second voltage detection device V2 does not rise when both the total negative relay J2 and the pre-filling relay J3 are closed, it is determined that the total negative relay J2 or the pre-filling relay J3 has a failure to close and is reported;

[0093] If the voltage detection value of the second voltage detection device V2 rises when the total negative relay J2 and the pre-charge relay J3 are both closed, but cannot rise to meet the second preset condition within the sixth preset time (for example, 0.1 seconds), it is determined that a load fault occurs in the power battery management system and is reported.

[0094] like Figure 2 As shown, in the process of opening and closing control and status detection of the relays in the power battery management system according to the charging mode timing or the driving mode timing, if a power-off command is received, the relays in the power battery management system are opened and closed and the status detection is performed according to the power-off mode timing.

[0095] Specifically, the power-off mode includes an emergency power-off mode and a normal power-off mode; it can be determined whether the power-off mode is an emergency power-off mode, and if so, all relays are controlled to open; otherwise, the relays are subjected to normal power-off mode timing control, and during the normal power-off mode timing control process, the relay status is detected according to the power parameters in the power battery management system to determine whether the relay in the power battery management system is faulty and the fault type, and a report is made when a relay fails; the fault type includes relay sticking or not being attracted.

[0096] like Figure 6 As shown, the opening and closing control and status detection of the relay in the power battery management system according to the power-off mode timing are as follows:

[0097] Determining a power-off mode in the power-off instruction;

[0098] If the power-off mode is the emergency power-off mode, the total positive relay J1 and the total negative relay J2 are controlled to open;

[0099] If the power-off mode is the normal power-off mode, the total negative relay J2 is controlled to open, and the voltage detection value of the second voltage detection device V2 is read, and it is determined whether the voltage detection value of the second voltage detection device V2 decreases; if so, the total positive relay J1 is controlled to open; if not, it is determined that the total positive relay J1 has a adhesion fault and reports it, and the total positive relay J1 is controlled to open at an interval of the seventh preset time.

[0100] The present invention provides a control detection method for a BMS relay, which controls each relay to open and close according to the requirements of the vehicle control strategy. When a serious fault occurs in the vehicle or the power battery, the relay is disconnected in time to ensure the service life of the power battery. When the relay itself fails, it can be identified under different working conditions, and the adhesion fault or the failure to attract fault of each relay is reported.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control detection method for a BMS relay, characterized in that: include: Determine the vehicle mode of the new energy vehicle, wherein the vehicle mode includes a charging mode and a driving mode; If the new energy vehicle is in the charging mode, the relay in the power battery management system of the new energy vehicle is opened and closed according to the charging mode timing sequence, and during the opening and closing control process, the relay state detection is performed according to the power parameters in the power battery management system to determine whether the relay in the power battery management system is faulty; If the new energy vehicle is in the driving mode, the relay in the power battery management system of the new energy vehicle is opened and closed according to the driving mode timing, and during the opening and closing control process, the relay state is detected according to the power parameters in the power battery management system to determine whether the relay in the power battery management system is faulty.

2. The control detection method of the BMS relay according to claim 1, characterized in that: The power battery management system comprises: Power battery; A total positive relay, one contact of which is connected to the positive electrode of the power battery; A total negative relay, one contact of which is connected to the negative electrode of the power battery; A load, one end of which is connected to the other contact of the total positive relay, and the other end of which is connected to the other contact of the total negative relay; A pre-charging relay, one contact of which is connected to one contact of the total positive relay, and the other contact of which is connected to the other contact of the total positive relay via a pre-charging resistor; A first voltage detection device, two ends of which are respectively connected to the positive electrode and the negative electrode of the power battery; A second voltage detection device, one end of which is connected to another contact of the total positive relay, and the other end of which is connected to another contact of the total negative relay; Among them, the total positive relay, the total negative relay and the pre-charging relay are relays in the power battery management system.

3. The control detection method of the BMS relay according to claim 2, characterized in that: The opening and closing control and status detection of the relay in the power battery management system of the new energy vehicle according to the charging mode timing are specifically as follows: S101, controlling the pre-charging relay to close, and executing S102; S102, reading a voltage detection value of the second voltage detection device, and determining whether the voltage detection value of the second voltage detection device decreases or remains unchanged; If not, it is determined that the total negative relay has a sticking fault and reported; If so, the total negative relay is controlled to be closed, and S103 is executed; S103, reading the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device, and determining whether the absolute value of the difference between the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device is less than a first preset voltage threshold; if not, executing S104; if yes, executing S105; S104, control the pre-charging relay to open, add 1 to the pre-charging times, and determine whether the pre-charging times are less than the first preset times; if so, control the pre-charging relay to close, and return to loop to execute S103; if not, determine that the total negative relay or the pre-charging relay fails to close or the power battery management system has a load failure; S105, first control the total positive relay to close, then control the pre-charge relay to open, and execute S106; S106, read the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device, and determine whether the difference between the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device is greater than a second preset voltage threshold; if not, determine that the power battery management system has no fault and maintain normal charging mode; if so, determine that the total positive relay has a failure to close and report it.

4. The control detection method of the BMS relay according to claim 3, characterized in that: In the S102, the total negative relay is controlled to be closed and then the S103 is executed after a first preset time interval; In S105, the pre-charging relay is controlled to open after a second preset time interval after the total positive relay is controlled to close.

5. The control detection method of the BMS relay according to claim 3, characterized in that: In S104, determining whether the total negative relay or the pre-charging relay fails to close or whether the power battery management system has a load failure is specifically as follows: If the voltage detection value of the second voltage detection device does not rise when both the total negative relay and the pre-filling relay are closed, it is determined that the total negative relay or the pre-filling relay has a failure to close and is reported; If the voltage detection value of the second voltage detection device rises when the total negative relay and the pre-charging relay are both closed, but cannot rise to meet the first preset condition within the third preset time, it is determined that a load fault occurs in the power battery management system and is reported.

6. The control detection method of the BMS relay according to claim 2, characterized in that: The opening and closing control and status detection of the relay in the power battery management system of the new energy vehicle according to the driving mode timing are specifically as follows: S201, controlling the total negative relay to close, and executing S202; S202, reading the voltage detection value of the second voltage detection device, and determining whether the voltage detection value of the second voltage detection device decreases or remains unchanged; if not, determining that the pre-charging relay has a sticking fault and reporting it; If so, execute S203; S203, controlling the pre-charging relay to close, reading the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device, and determining whether the absolute value of the difference between the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device is less than a third preset voltage threshold; if not, executing S204; if yes, executing S205; S204, control the pre-charging relay to open, add 1 to the pre-charging times, and determine whether the pre-charging times are less than the second preset times; if so, return to loop and execute S203; if not, determine that the total negative relay or the pre-charging relay has a failure to close or the power battery management system has a load failure; S205, first control the total positive relay to close, then control the pre-charge relay to open, and execute S206; S206, reading the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device, and determining whether the difference between the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device is greater than a fourth preset voltage threshold; if not, determining that the power battery management system has no fault and maintaining a normal driving mode; If so, it is determined that the total positive relay fails to close and reports the failure.

7. The control detection method of the BMS relay according to claim 6, characterized in that: In the S203, after the pre-charging relay is closed, the voltage detection value of the first voltage detection device and the voltage detection value of the second voltage detection device are read at a fourth preset time interval; In S205, the pre-charging relay is controlled to open after a fifth preset time interval after the total positive relay is controlled to close.

8. The control detection method of the BMS relay according to claim 6, characterized in that: In S204, determining whether the total negative relay or the pre-charging relay fails to close or whether the power battery management system has a load failure is specifically as follows: If the voltage detection value of the second voltage detection device does not rise when both the total negative relay and the pre-filling relay are closed, it is determined that the total negative relay or the pre-filling relay has a failure to close and is reported; If the voltage detection value of the second voltage detection device rises when the total negative relay and the pre-charging relay are both closed, but cannot rise to meet the second preset condition within the sixth preset time, it is determined that a load fault occurs in the power battery management system and is reported.

9. The control detection method of the BMS relay according to claim 2, characterized in that: In the process of opening and closing control and status detection of the relays in the power battery management system according to the charging mode timing or the driving mode timing, if a power-off command is received, the opening and closing control and status detection of the relays in the power battery management system are performed according to the power-off mode timing.

10. The control and detection method of the BMS relay according to claim 9, characterized in that: According to the power-off mode timing, the relays in the power battery management system are opened and closed and the status is detected as follows: Determine a power-off mode in the power-off instruction; the power-off mode includes an emergency power-off mode and a normal power-off mode; If the power-off mode is the emergency power-off mode, controlling the total positive relay and the total negative relay to open; If the power-off mode is the normal power-off mode, the total negative relay is controlled to open, and the voltage detection value of the second voltage detection device is read, and it is determined whether the voltage detection value of the second voltage detection device decreases; if so, the total positive relay is controlled to open; If not, it is determined that the main positive relay has a sticking fault and reported, and the main positive relay is controlled to open at an interval of the seventh preset time.

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