Online dual-circuit power supply diagnosis circuit, method and storage medium

Abstract

The present application relates to an online dual-power supply diagnosis circuit, method and storage medium, wherein the online dual-power supply diagnosis circuit comprises a battery pack module and a battery management system module; the battery pack module comprises a first lithium battery and a relay; the battery management system module comprises a BAT power supply circuit module electrically connected to a power supply point A, a KL power supply circuit module electrically connected to a power supply point B and connected in parallel with the BAT power supply circuit module, a diagnostic circuit module electrically connected to both the BAT power supply circuit module and the KL power supply circuit module, a second lithium battery electrically connected to the diagnostic circuit module and to the first lithium battery, and an MCU control module electrically connected to the BAT power supply circuit module, the KL power supply circuit module and the diagnostic circuit module; the BMS battery management system can realize autonomous diagnosis, and can realize online diagnosis without disconnecting the relay during vehicle driving, and has strong diagnostic flexibility.

Description

Technical Field

[0001] The present application relates to the technical field of low-voltage battery management systems for new energy vehicles, and in particular to an online dual-power supply diagnosis circuit, method and storage medium. Background Art

[0002] In recent years, the new energy industry has developed rapidly. With the lightweight and improved performance of the whole vehicle, the whole vehicle gradually adopts lithium batteries to replace traditional lead-acid batteries as low-voltage power supply. With the safety issues, BMS (BATTERY MANAGEMENT SYSTEM) is generally equipped on the lithium battery to monitor the status of the lithium battery in real time; it alarms in advance or actively disconnects the discharge circuit before a fault occurs to ensure the safety of the whole vehicle; usually a relay is added between the positive electrode of the lithium battery and the positive electrode of the battery pack so that the BMS can cut off the external power supply circuit of the battery pack by cutting off the relay to ensure that the battery enters a safe state; the voltage required for the BMS to work is mainly provided by low-voltage lithium batteries. In order to prevent the battery from feeding and causing the BMS to fail to work, the BMS power supply usually adopts dual-way power supply to ensure that the BMS can be started by external power supply when the battery pack feed relay is disconnected and the BMS cannot work; since the BMS is powered by dual power supplies, in order to meet the functional safety requirements, each power supply needs to be diagnosed separately to ensure that protective measures are taken or the driver is notified to take safety actions in the abnormal power supply state to avoid some unnecessary safety accidents.

[0003] In order to meet the requirements of the reverse connection function of electrical testing, the current dual-power supply system adds a diode to each power supply input end to prevent reverse connection and short circuit of the dual power supply under certain circumstances. There are problems with the existing dual-path diagnosis scheme: 1. It requires the participation of an external DCDC (Direct Current-DC power converter), the diagnostic logic is complex, and it cannot be diagnosed when the DCDC is abnormal, and the reliability is poor; 2. The diagnostic logic is carried out when the relay needs to be disconnected, and the diagnosis can only be performed during the parking process. It cannot be diagnosed during the use of the vehicle. The diagnostic flexibility is poor, and a fault cannot be diagnosed in real time during driving. Summary of the invention

[0004] The embodiments of the present application provide an online dual-power supply diagnosis circuit, method and storage medium, which can realize autonomous diagnosis of the BMS battery management system. The diagnostic logic is simple and there is no need to disconnect the relay during the driving process of the vehicle. Online diagnosis can be realized, and dual-power supply faults can be diagnosed in real time, with strong diagnostic flexibility.

[0005] In a first aspect, an online dual-power supply diagnostic circuit is provided, comprising a battery pack module and a battery management system module; the battery pack module comprises a first lithium battery, and a relay arranged between the positive electrode of the first lithium battery and the negative electrode of the first lithium battery; wherein the connection node between one end of the relay and the positive electrode of the first lithium battery is set as a power supply point A, and the connection node between the other end of the relay and the positive electrode of the first lithium battery is set as a power supply point B; the battery management system module comprises a BAT power supply circuit module electrically connected to the power supply point A, a KL power supply circuit module electrically connected to the power supply point B and connected in parallel with the BAT power supply circuit module, a diagnostic circuit module electrically connected to the BAT power supply circuit module and the KL power supply circuit module respectively, a second lithium battery electrically connected to the diagnostic circuit module and electrically connected to the first lithium battery, and an MCU control module electrically connected to the BAT power supply circuit module, the KL power supply circuit module and the diagnostic circuit module; wherein the connection node between the diagnostic circuit module and the positive electrode of the second lithium battery is set as a convergence power point C, and the KL power supply circuit module is electrically connected to the convergence power point C.

[0006] In some embodiments, the BAT power supply circuit module includes a first resistor, a second resistor, a first sampling voltage output terminal and a first diode; one end of the first resistor is electrically connected to the power supply point A, the other end of the first resistor is electrically connected to one end of the second resistor, the other end of the second resistor is grounded, the positive electrode of the first diode is electrically connected to one end of the first resistor and the power supply point A respectively, and the negative electrode of the first diode is electrically connected to the diagnostic circuit module; wherein, the connection node between the first resistor and the second resistor is electrically connected to the first sampling voltage output terminal, and the MCU control module is electrically connected to the first sampling voltage output terminal.

[0007] In some embodiments, the KL power supply loop module includes a third resistor, a fourth resistor, a second sampling voltage output terminal, a second diode and a third diode; one end of the third resistor is electrically connected to the power supply point B, the other end of the third resistor is electrically connected to one end of the fourth resistor, the other end of the fourth resistor is grounded, the positive electrode of the second diode is electrically connected to one end of the third resistor and the power supply point B respectively, the negative electrode of the second diode is electrically connected to the positive electrode of the third diode, and the negative electrode of the third diode is electrically connected to the diagnostic loop module; wherein, the connection node between the third resistor and the fourth resistor is electrically connected to the second sampling voltage output terminal, and the MCU control module is electrically connected to the second sampling voltage output terminal.

[0008] In some embodiments, the diagnostic loop module includes a fourth diode, a fifth diode, a MOS tube, a fifth resistor, a sixth resistor and a third sampling voltage output terminal; the anode of the fourth diode is electrically connected to the cathode of the first diode, the cathode of the fourth diode is electrically connected to the anode of the fifth diode, the cathode of the fifth diode is electrically connected to the convergence power point C, one end of the MOS tube is electrically connected to the cathode of the first diode, the other end of the MOS tube is electrically connected to the convergence power point C, one end of the fifth resistor is electrically connected to the convergence power point C, the other end of the fifth resistor is electrically connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded; wherein the connection node between the fifth resistor and the sixth resistor is electrically connected to the third sampling voltage output terminal, and the MCU control module is electrically connected to the third sampling voltage output terminal.

[0009] In some embodiments, the negative electrode of the second lithium battery is electrically connected to the negative electrode of the first lithium battery.

[0010] In some embodiments, the KL power supply loop module is a KL30 power supply loop module.

[0011] In a second aspect, an online dual-power supply diagnosis method is provided, which is applied to the online dual-power supply diagnosis circuit as described above, and includes the following steps:

[0012] Control the relay closure and MOS tube closure, and determine the power supply status of the BAT power supply circuit module;

[0013] When it is detected that the power supply status of the BAT power supply circuit module is normal, the MOS tube is controlled to be disconnected, and the power supply status of the KL power supply circuit module is determined.

[0014] In some embodiments, the step of “controlling the relay to close and the MOS tube to close, and determining the power supply status of the BAT power supply circuit module” includes the following steps:

[0015] Control the relay to close and the MOS tube to close;

[0016] The MCU control module detects the voltage V at the power supply point A respectively A1 , the voltage V at the power supply point B B1 , the voltage V at the power collection point C C1 ;

[0017] When V C1 —V A1 =V d +V q , it is judged that the power supply status of the BAT power supply circuit module is normal;

[0018] When V C1—V A1 =2V d , it is judged that the power supply status of the BAT power supply circuit module is abnormal;

[0019] Among them, V q is the voltage drop of the MOS tube; V d is the diode positive electrode voltage drop.

[0020] In some embodiments, the step of “when detecting that the power supply status of the BAT power supply circuit module is normal, controlling the MOS tube to disconnect, and determining the power supply status of the KL power supply circuit module” includes the following steps:

[0021] When it is detected that the power supply status of the BAT power supply circuit module is normal, the control MOS tube is disconnected;

[0022] The MCU control module detects the voltage V at the power supply point A respectively A2 , the voltage V at the power supply point B B2 , the voltage V at the power collection point C C2 ;

[0023] When V C2 —V B2 =2V d , it is judged that the power supply status of the KL power supply circuit module is normal;

[0024] When V C2 —V B2 =3V d , it is judged that the power supply status of the KL power supply circuit module is abnormal.

[0025] In a third aspect, a storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the online dual-power supply diagnosis method as described above is implemented.

[0026] The beneficial effects brought about by the technical solution provided in the present application include: when the online dual-power supply diagnostic circuit performs dual-path diagnosis on the KL power supply loop module and the KL power supply loop module, there is no need for the participation of external DCDC or other components of the whole vehicle, and the BMS battery management system can realize autonomous diagnosis, the diagnostic logic is simple, and real-time and accurate diagnosis of whether the dual-path power supply is abnormal; at the same time, there is no need to disconnect the relay during the driving process of the whole vehicle, and online diagnosis can be realized, real-time diagnosis of dual-path power supply faults is achieved, and the diagnostic flexibility is strong, ensuring that the fault is diagnosed in time and timely measures are taken when it is discovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A circuit diagram of an online dual-power supply diagnostic circuit provided in an embodiment of the present application;

[0029] Figure 2 It is a flowchart diagram of an embodiment of an online dual power supply diagnosis method of the present application.

[0030] 100, battery pack module; 110, first lithium battery; 200, battery management system module; 210, BAT power supply circuit module; 220, KL power supply circuit module; 230, diagnostic circuit module; 240, second lithium battery; 250, MCU control module. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0032] See also Figure 1As shown, the embodiment of the present application provides an online dual-power supply diagnostic circuit, including a battery pack module 100 and a battery management system module 200; the battery pack module 100 includes a first lithium battery 110 and a relay K arranged between the positive electrode of the first lithium battery 110 and the negative electrode of the first lithium battery 110; wherein, the connection node between one end of the relay K and the positive electrode of the first lithium battery 110 is set as a power supply point A, and the connection node between the other end of the relay K and the positive electrode of the first lithium battery 110 is set as a power supply point B; the battery management system module 200 includes a BAT power supply circuit module 210 electrically connected to the power supply point A, and a BAT power supply circuit module 210 electrically connected to the power supply point B and connected to the BAT power supply circuit module 210. A KL power supply circuit module 220 connected in parallel with the circuit module 210, a diagnostic circuit module 230 electrically connected to the BAT power supply circuit module 210 and the KL power supply circuit module 220 respectively, a second lithium battery 240 electrically connected to the diagnostic circuit module 230 and electrically connected to the first lithium battery 110, and an MCU control module 250 electrically connected to the BAT power supply circuit module 210, the KL power supply circuit module 220 and the diagnostic circuit module 230; wherein the connection node between the diagnostic circuit module 230 and the positive electrode of the second lithium battery 240 is set to a convergence power point C, and the KL power supply circuit module 220 is electrically connected to the convergence power point C.

[0033] MCU-Microcontroller Unit, microprocessor unit or single chip microcomputer; in the online dual-power supply diagnosis circuit, first control the relay K to close and the diagnosis circuit module 230 to close, and then control the MCU control module 250 to detect the voltage V of the power supply point A respectively A1 , the voltage V at the power supply point B B1 , the voltage V at the power collection point C C1 ; When V C1 —V A1 =V d +V q , it is determined that the power supply state of the BAT power supply circuit module 210 is normal; when V C1 —V A1 =2V d , it is determined that the power supply state of the BAT power supply circuit module 210 is abnormal. When the power supply state of the BAT power supply circuit module 210 is normal, the control diagnosis circuit module 230 is disconnected; the control MCU control module 250 detects the voltage V of the power supply point A respectively. A2 , the voltage V at the power supply point B B2 , the voltage V at the power collection point C C2 ; When V C2 —V B2 =2V d, it is determined that the power supply status of the KL power supply circuit module 220 is normal; when V C2 —V B2 =3V d , it is determined that the power supply status of the KL power supply circuit module 220 is abnormal.

[0034] Therefore, when the online dual-power supply diagnostic circuit performs dual-path diagnosis on the KL power supply circuit module 220 and the KL power supply circuit module 220, no external DCDC or other components of the vehicle are required to participate, and the BMS battery management system can be autonomously diagnosed. The diagnostic logic is simple, and it can accurately diagnose whether the dual-path power supply is abnormal in real time. At the same time, there is no need to disconnect the relay during the driving process of the vehicle, and online diagnosis can be realized. The dual-path power supply fault is diagnosed in real time, and the diagnostic flexibility is strong, ensuring that the fault is diagnosed in time and measures are taken in time.

[0035] Optionally, the BAT power supply circuit module 210 includes a first resistor R1, a second resistor R2, a first sampling voltage output terminal ADC1 (ADC, Analog-to-Digital Converter) and a first diode D1; one end of the first resistor R1 is electrically connected to the power supply point A, the other end of the first resistor R1 is electrically connected to one end of the second resistor R2, the other end of the second resistor R2 is grounded, the positive electrode of the first diode D1 is electrically connected to one end of the first resistor R1 and the power supply point A respectively, and the negative electrode of the first diode D1 is electrically connected to the diagnostic circuit module 230; wherein, the connection node between the first resistor R1 and the second resistor R2 is electrically connected to the first sampling voltage output terminal ADC1, and the MCU control module 250 is electrically connected to the first sampling voltage output terminal ADC1. By electrically connecting the MCU control module 250 to the first sampling voltage output terminal ADC1, the voltage of the power supply point A can be detected, and voltage data can be provided for the online dual-channel power supply diagnostic circuit.

[0036] Optionally, KL indicates the state where the car power is connected. The KL power supply circuit module 220 includes a third resistor R3, a fourth resistor R4, a second sampling voltage output terminal ADC2, a second diode D2 and a third diode D3; one end of the third resistor R3 is electrically connected to the power supply point B, the other end of the third resistor R3 is electrically connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is grounded, the positive electrode of the second diode D2 is electrically connected to one end of the third resistor R3 and the power supply point B respectively, the negative electrode of the second diode D2 is electrically connected to the positive electrode of the third diode D3, and the negative electrode of the third diode D3 is electrically connected to the diagnostic circuit module 230; wherein the connection node between the third resistor R3 and the fourth resistor R4 is electrically connected to the second sampling voltage output terminal ADC2, and the MCU control module 250 is electrically connected to the second sampling voltage output terminal ADC2. By electrically connecting the MCU control module 250 to the second sampling voltage output terminal ADC2, the voltage of the power supply point B can be detected, and voltage data can be provided for the online dual-channel power supply diagnostic circuit.

[0037] Optionally, the diagnostic loop module 230 includes a fourth diode D4, a fifth diode D5, a MOS tube Q, a fifth resistor R5, a sixth resistor R6 and a third sampling voltage output terminal ADC3; the anode of the fourth diode D4 is electrically connected to the cathode of the first diode D1, the cathode of the fourth diode D4 is electrically connected to the anode of the fifth diode D5, the cathode of the fifth diode D5 is electrically connected to the convergence power point C, one end of the MOS tube Q is electrically connected to the cathode of the first diode D1, and the MOS tube Q (MOS tube: metal-oxide) is electrically connected to the cathode of the first diode D1. -semiconductor field effect transistor, or metal-insulator-semiconductor) is electrically connected to the convergence power point C, one end of the fifth resistor R5 is electrically connected to the convergence power point C, the other end of the fifth resistor R5 is electrically connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is grounded; wherein, the connection node between the fifth resistor R5 and the sixth resistor R6 is electrically connected to the third sampling voltage output terminal ADC, and the MCU control module 250 is electrically connected to the third sampling voltage output terminal ADC. By electrically connecting the MCU control module 250 to the third sampling voltage output terminal ADC3, the voltage of the power supply point C can be detected, and voltage data can be provided for the online dual-channel power supply diagnosis circuit.

[0038] Optionally, the negative electrode of the second lithium battery 240 is electrically connected to the negative electrode of the first lithium battery 110. Optionally, the KL power supply circuit module 220 is a KL30 power supply circuit module. KL30 is the ECU (Electronic Control Unit) power supply (i.e. connected to the vehicle battery), providing the ECU with an operating voltage of generally 11V to 15V. Some ECUs can operate when the car is turned off (corresponding to the OFF state of the car key).

[0039] See also Figure 2 As shown, the embodiment of the present application also provides an online dual-power supply diagnosis method, which is applied to the online dual-power supply diagnosis circuit described above, and includes the following steps:

[0040] S100, controlling the relay to close and the MOS tube to close, and determining the power supply status of the BAT power supply circuit module;

[0041] S200, when it is detected that the power supply status of the BAT power supply circuit module is normal, the MOS tube is controlled to be disconnected, and the power supply status of the KL power supply circuit module is determined.

[0042] Therefore, when the online dual-power supply diagnosis circuit performs dual-path diagnosis on the KL power supply loop module and the KL power supply loop module, there is no need for the participation of external DCDC or other components of the vehicle, and the BMS battery management system can be independently diagnosed. The diagnostic logic is simple, and it can accurately diagnose whether the dual-path power supply is abnormal in real time. At the same time, there is no need to disconnect the relay during the driving process of the vehicle, and online diagnosis can be realized. The dual-path power supply fault is diagnosed in real time, and the diagnostic flexibility is strong, ensuring that the fault is diagnosed in time and measures are taken in time.

[0043] In another embodiment of the present invention, the step of “S100, controlling the relay to close and the MOS tube to close, and determining the power supply state of the BAT power supply circuit module” includes the following steps:

[0044] S110, control relay closure and MOS tube closure;

[0045] S120, control the MCU control module to detect the voltage V of the power supply point A respectively A1 , the voltage V at the power supply point B B1 , the voltage V at the power collection point C C1 ;

[0046] S130, when V C1 —V A1 =V d +V q , it is judged that the power supply status of the BAT power supply circuit module is normal;

[0047] S140, when VC1 —V A1 =2V d , it is judged that the power supply status of the BAT power supply circuit module is abnormal.

[0048] Among them, V q is the voltage drop of the MOS tube, V q ≈0.2V; V d is the diode positive electrode voltage drop, V d ≈0.7V.

[0049] In another embodiment of the present invention, the step of “S200, when it is detected that the power supply status of the BAT power supply circuit module is normal, the MOS tube is controlled to be disconnected, and the power supply status of the KL power supply circuit module is determined” includes the following steps:

[0050] S210, when it is detected that the power supply status of the BAT power supply circuit module is normal, the MOS tube is controlled to be disconnected;

[0051] S220, control the MCU control module to detect the voltage V of the power supply point A respectively A2 , the voltage V at the power supply point B B2 , the voltage V at the power collection point C C2 ;

[0052] S220, when V C2 —V B2 =2V d , it is judged that the power supply status of the KL power supply circuit module is normal;

[0053] S230, when V C2 —V B2 =3V d , it is judged that the power supply status of the KL power supply circuit module is abnormal.

[0054] In another embodiment of the present invention, the embodiment of the present application further provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the online dual power supply diagnosis method as described above is implemented.

[0055] Based on the same inventive concept, an embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, all or part of the method steps of the above method are implemented.

[0056] The present invention implements all or part of the process in the above method, and can also be completed by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of each method embodiment can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying computer program code, recording medium, USB flash drive, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electric carrier signals and telecommunication signals.

[0057] Based on the same inventive concept, an embodiment of the present application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program running on the processor, and when the processor executes the computer program, all or part of the method steps in the above method are implemented.

[0058] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of a computer device, and uses various interfaces and lines to connect various parts of the entire computer device.

[0059] The memory can be used to store computer programs and / or modules. The processor realizes various functions of the computer device by running or executing the computer programs and / or modules stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system and at least one application required for a function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the mobile phone (such as audio data, video data, etc.). In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (SmartMedia Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0060] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, servers or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer-usable program codes.

[0061] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), servers, and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as a combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0062] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0063] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0064] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. An online dual-circuit power supply diagnostic circuit, characterized in that: include: A battery pack module, comprising a first lithium battery, and a relay disposed between the positive electrode of the first lithium battery and the negative electrode of the first lithium battery; wherein a connection node between one end of the relay and the positive electrode of the first lithium battery is set as a power supply point A, and a connection node between the other end of the relay and the positive electrode of the first lithium battery is set as a power supply point B; and, A battery management system module, comprising a BAT power supply circuit module electrically connected to the power supply point A, a KL power supply circuit module electrically connected to the power supply point B and connected in parallel with the BAT power supply circuit module, a diagnostic circuit module electrically connected to the BAT power supply circuit module and the KL power supply circuit module respectively, a second lithium battery electrically connected to the diagnostic circuit module and electrically connected to the first lithium battery, and an MCU control module electrically connected to the BAT power supply circuit module, the KL power supply circuit module and the diagnostic circuit module; wherein the connection node between the diagnostic circuit module and the positive electrode of the second lithium battery is set to a convergence power point C, and the KL power supply circuit module is electrically connected to the convergence power point C; The BAT power supply circuit module includes a first resistor, a second resistor, a first sampling voltage output terminal and a first diode, one end of the first resistor is electrically connected to the power supply point A, the other end of the first resistor is electrically connected to one end of the second resistor, the other end of the second resistor is grounded, the positive electrode of the first diode is electrically connected to one end of the first resistor and the power supply point A respectively, and the negative electrode of the first diode is electrically connected to the diagnostic circuit module; wherein, the connection node between the first resistor and the second resistor is electrically connected to the first sampling voltage output terminal, and the MCU control module is electrically connected to the first sampling voltage output terminal; The KL power supply loop module includes a third resistor, a fourth resistor, a second sampling voltage output terminal, a second diode and a third diode, one end of the third resistor is electrically connected to the power supply point B, the other end of the third resistor is electrically connected to one end of the fourth resistor, the other end of the fourth resistor is grounded, the positive electrode of the second diode is electrically connected to one end of the third resistor and the power supply point B respectively, the negative electrode of the second diode is electrically connected to the positive electrode of the third diode, and the negative electrode of the third diode is electrically connected to the diagnostic loop module; wherein, the connection node between the third resistor and the fourth resistor is electrically connected to the second sampling voltage output terminal, and the MCU control module is electrically connected to the second sampling voltage output terminal; The diagnostic loop module includes a fourth diode, a fifth diode, a MOS tube, a fifth resistor, a sixth resistor and a third sampling voltage output end, the anode of the fourth diode is electrically connected to the cathode of the first diode, the cathode of the fourth diode is electrically connected to the anode of the fifth diode, the cathode of the fifth diode is electrically connected to the convergence power point C, one end of the MOS tube is electrically connected to the cathode of the first diode, the other end of the MOS tube is electrically connected to the convergence power point C, one end of the fifth resistor is electrically connected to the convergence power point C, the other end of the fifth resistor is electrically connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded; wherein, the connection node between the fifth resistor and the sixth resistor is electrically connected to the third sampling voltage output end, and the MCU control module is electrically connected to the third sampling voltage output end.

2. The online dual power supply diagnostic circuit according to claim 1, characterized in that: The negative electrode of the second lithium battery is electrically connected to the negative electrode of the first lithium battery.

3. The online dual-power supply diagnostic circuit according to claim 1, characterized in that: The KL power supply circuit module is a KL30 power supply circuit module.

4. An online dual-power supply diagnosis method, applied to the online dual-power supply diagnosis circuit as described in any one of claims 1 to 3, characterized in that: The following steps are involved: Control the relay closure and MOS tube closure, and determine the power supply status of the BAT power supply circuit module; When it is detected that the power supply status of the BAT power supply circuit module is normal, the MOS tube is controlled to be disconnected, and the power supply status of the KL power supply circuit module is determined.

5. The online dual-power supply diagnosis method according to claim 4, characterized in that: The step of "controlling the relay to close and the MOS tube to close, and determining the power supply status of the BAT power supply circuit module" includes the following steps: Control the relay to close and the MOS tube to close; The control MCU control module detects the voltage VA1 of the power supply point A and the voltage V of the power supply point B respectively. B1 , the voltage V at the power collection point C C1 ; When V C1— VA1=V d +V q , it is judged that the power supply status of the BAT power supply circuit module is normal; When V C1— VA1=2V d , it is judged that the power supply status of the BAT power supply circuit module is abnormal; Among them, V q is the voltage drop of the MOS tube; V d is the diode positive electrode voltage drop.

6. The online dual-power supply diagnosis method according to claim 5, characterized in that: The step of "when detecting that the power supply status of the BAT power supply circuit module is normal, controlling the MOS tube to disconnect, and determining the power supply status of the KL power supply circuit module" includes the following steps: When it is detected that the power supply status of the BAT power supply circuit module is normal, the control MOS tube is disconnected; The control MCU control module detects the voltage VA2 of the power supply point A and the voltage V of the power supply point B respectively. B2 , the voltage V at the power collection point C C2； When V C2— VB2=2V d ， It is judged that the power supply status of the KL power supply circuit module is normal; When V C2— VB2=3V d ， It is determined that the power supply status of the KL power supply circuit module is abnormal.

7. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the online dual power supply diagnosis method according to any one of claims 4 to 6 is implemented.

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