A pre-charging control method and device of a vehicle battery management system, a terminal device, and a storage medium

Abstract

The application discloses a kind of pre-charging control method, device, terminal equipment and storage medium of vehicle battery management system, by when obtaining high voltage power-on instruction, obtaining starting power supply voltage and the first output voltage of direct current converter, and when determining that the first output voltage or starting power supply voltage is greater than first preset voltage, pre-charging relay is closed, to make pre-charging to direct current bus capacitor, therefore, the safety of the vehicle in the process of high voltage power-on is effectively guaranteed, second, by monitoring the voltage difference inside and outside battery and direct current bus voltage simultaneously during pre-charging to determine whether the direct current bus capacitor is pre-charged, to avoid direct current bus voltage being affected when vehicle system is under voltage, leading to the situation that BMS misjudges pre-charging completion occurs, effectively reduce the risk of BMS misjudgment, avoid current acquisition circuit being impacted by large surge, enhance the reliability and stability of battery management system, improve the safety performance of electric vehicle.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to a pre-charge control method, device, terminal equipment, and storage medium for a vehicle battery management system. Background Technology

[0002] In the electric vehicle (EV) field, the Battery Management System (BMS) plays a crucial role in ensuring the safety and reliability of the battery pack. When an EV is powered on via its high-voltage circuit, the BMS controls the pre-charge relay to close, charging the DC bus capacitor. This gradually increases the DC bus capacitor voltage until it reaches a level equal to or close to the battery voltage. Then, the battery is directly connected to the high-voltage bus via the main relay. This process aims to prevent high-voltage surges from damaging high-voltage components, thereby improving the safety and reliability of the high-voltage system. During this process, the BMS's current acquisition function is used to monitor changes in the pre-charge current. By acquiring the DC bus current, it's possible to determine whether the pre-charge process is proceeding normally and whether pre-charge is complete. Once pre-charge is deemed complete, the BMS controls the main positive relay to close, officially outputting high-voltage electricity to the external load.

[0003] Existing BMS (Battery Management System) generally employs a current acquisition scheme based on a series shunt. However, this scheme has certain drawbacks when the vehicle system is undervoltage. When the vehicle is undervoltage, the DC bus voltage is affected, leading to inaccurate or invalid voltage values. This can cause the BMS to misjudge whether pre-charging is complete based on the DC bus voltage. In particular, when the bus voltage sends the maximum invalid value, the BMS may mistakenly believe that pre-charging is complete, causing the pre-charging relay and main relay to close simultaneously, resulting in a large surge voltage. This surge voltage can damage the components in the current acquisition circuit. Summary of the Invention

[0004] This invention provides a pre-charge control method, device, terminal equipment, and storage medium for a vehicle battery management system, which effectively reduces the risk of BMS pre-charge misjudgment, enhances the reliability and stability of the battery management system, and improves the safety performance of electric vehicles.

[0005] An embodiment of the present invention provides a pre-charge control method for a vehicle battery management system, comprising:

[0006] Receive high-voltage power-on command;

[0007] According to the high-voltage power-on command, the startup power supply voltage and the first output voltage of the DC-DC converter are obtained;

[0008] When it is determined that the first output voltage or the starting power supply voltage is greater than the first preset voltage, the pre-charge relay is closed to pre-charge the DC bus capacitor.

[0009] Monitor the voltage difference between the inside and outside of the battery and the DC bus voltage, and determine whether the DC bus capacitor has been pre-charged based on the voltage difference between the inside and outside of the battery and the DC bus voltage.

[0010] When the pre-charging of the DC bus capacitor is confirmed to be complete, the pre-charging relay is controlled to open, and the main positive relay is controlled to close.

[0011] Furthermore, determining whether the DC bus capacitor has completed pre-charging based on the voltage difference between the inside and outside of the battery and the DC bus voltage includes:

[0012] When the voltage difference between the inside and outside of the battery is less than the second preset voltage for a first maintenance time that is not less than the first preset time, and the DC bus voltage is within the range of the first preset voltage, the DC bus capacitor is confirmed to be pre-charged.

[0013] Furthermore, the step of determining whether the DC bus capacitor has completed pre-charging based on the voltage difference between the inside and outside of the battery and the DC bus voltage also includes:

[0014] When the second maintenance duration is determined to be no less than the second preset duration and the voltage difference between the inside and outside of the battery is no less than the second preset voltage, the pre-charging of the DC bus capacitor is confirmed to have failed.

[0015] Furthermore, the step of determining whether the DC bus capacitor has completed pre-charging based on the voltage difference between the inside and outside of the battery and the DC bus voltage also includes:

[0016] When the first maintenance time for which the voltage difference between the inside and outside of the battery is less than the second preset voltage is not less than the first preset time, and the DC bus voltage is not within the range of the first preset voltage, the second output voltage of the charger is obtained.

[0017] Determine whether the second output voltage is within the second preset voltage range;

[0018] If so, then confirm that the DC bus capacitor pre-charging is complete;

[0019] If not, then the DC bus capacitor pre-charge has failed.

[0020] Furthermore, after confirming that the DC bus capacitor pre-charging has failed, the process also includes:

[0021] Disconnect the precharge relay and obtain the precharge failure count;

[0022] When the precharge failure count is determined to be less than a preset number of times, the precharge failure count is incremented by one, and after a preset waiting time, the precharge relay is closed again.

[0023] When the precharge failure count is determined to be not less than a preset threshold number, a precharge failure alarm is issued.

[0024] Another embodiment of the present invention provides a pre-charge control device for a vehicle battery management system, comprising:

[0025] The instruction acquisition module is used to acquire high-voltage power-on instructions;

[0026] The voltage acquisition module is used to acquire the startup power supply voltage and the first output voltage of the DC-DC converter according to the high voltage power-on command.

[0027] The precharge execution module is used to close the precharge relay when it is determined that the first output voltage or the starting power supply voltage is greater than the first preset voltage, so as to precharge the DC bus capacitor.

[0028] The pre-charge monitoring module is used to monitor the voltage difference between the inside and outside of the battery and the DC bus voltage, and to determine whether the DC bus capacitor has been pre-charged based on the voltage difference between the inside and outside of the battery and the DC bus voltage.

[0029] The pre-charge completion module is used to control the pre-charge relay to open and the main positive relay to close when it is confirmed that the DC bus capacitor has been pre-charged.

[0030] Furthermore, the pre-charge monitoring module determines whether the DC bus capacitor has completed pre-charging based on the voltage difference between the inside and outside of the battery and the DC bus voltage, including:

[0031] When the voltage difference between the inside and outside of the battery is less than the second preset voltage for a first maintenance time that is not less than the first preset time, and the DC bus voltage is within the range of the first preset voltage, the DC bus capacitor is confirmed to be pre-charged.

[0032] Furthermore, the pre-charge monitoring module, based on the voltage difference between the inside and outside of the battery and the DC bus voltage, determines whether the DC bus capacitor has been pre-charged, and further includes:

[0033] When the second maintenance duration is determined to be no less than the second preset duration and the voltage difference between the inside and outside of the battery is no less than the second preset voltage, the pre-charging of the DC bus capacitor is confirmed to have failed.

[0034] Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements a pre-charge control method for a vehicle battery management system as described in any of the embodiments.

[0035] Another embodiment of the present invention provides a storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the storage medium is located to perform a pre-charge control method for a vehicle battery management system as described in any of the above embodiments.

[0036] The following benefits can be obtained by implementing the present invention:

[0037] This invention discloses a pre-charge control method, device, terminal equipment, and storage medium for a vehicle battery management system. The method is applied to the battery management system. When a high-voltage power-on command is received, the system acquires the starting power supply voltage and the first output voltage of the DC-DC converter. When the first output voltage or the starting power supply voltage is determined to be greater than a first preset voltage, a pre-charge relay is closed to pre-charge the DC bus capacitor. Before pre-charging, this invention uses the first output voltage and the starting power supply voltage to determine whether the vehicle meets the conditions for initiating pre-charging, ensuring vehicle safety during high-voltage power-on. Furthermore, during pre-charging, the system monitors the voltage difference between the inside and outside of the battery and the DC bus voltage to determine whether the DC bus capacitor is pre-charged. This avoids the DC bus voltage being affected when the vehicle system is undervoltage, which could lead to the BMS misjudging pre-charging completion. This effectively reduces the risk of BMS misjudgment, prevents the current acquisition circuit from being impacted by large surges, enhances the reliability and stability of the battery management system, and improves the safety performance of electric vehicles. Attached Figure Description

[0038] Figure 1 This is a flowchart illustrating a pre-charge control method for a vehicle battery management system according to an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of the structure of a pre-charge control device for a vehicle battery management system according to an embodiment of the present invention.

[0040] Figure 3 This is a schematic diagram of the current acquisition circuit provided in an embodiment of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0043] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0046] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0047] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0048] See Figure 1 This is a flowchart illustrating a pre-charge control method for a vehicle battery management system according to an embodiment of the present invention, comprising:

[0049] S1. Obtain the high-voltage power-on command;

[0050] In a preferred embodiment of the present invention, when the vehicle is ready to start or accelerate and a series of safety and preparation conditions have been met, the vehicle controller sends a high-voltage power-on command to the BMS through an internal communication protocol (such as CAN bus).

[0051] S2. According to the high voltage power-on command, obtain the startup power supply voltage and the first output voltage of the DC-DC converter;

[0052] S3. When it is determined that the first output voltage or the starting power supply voltage is greater than the first preset voltage, the pre-charge relay is closed to pre-charge the DC bus capacitor.

[0053] In a preferred embodiment of the present invention, the first preset voltage is set to 8V. It is understood that the DC-DC converter plays a crucial role in voltage conversion in electric vehicles. This conversion process is essential for battery charging and power supply to in-vehicle electronic devices. If the output voltage of the DC-DC converter is stable and greater than the first preset voltage, the vehicle's power system can be considered to be in normal working order, providing the basic conditions for the pre-charging process. Alternatively, the vehicle's pre-charging can be determined by the BMS self-checking the lead-acid voltage. The starting power supply voltage (BMS self-checking lead-acid voltage) is the voltage provided by the battery pack when the vehicle is started. This voltage value is directly significant in determining whether the vehicle can start pre-charging. Therefore, this embodiment sets a threshold value for the starting power supply voltage (the first preset voltage). Only when the starting power supply voltage is greater than this threshold will the BMS consider the condition met and thus initiate the pre-charging process.

[0054] S4. Monitor the voltage difference between the inside and outside of the battery and the DC bus voltage, and determine whether the DC bus capacitor has been pre-charged based on the voltage difference between the inside and outside of the battery and the DC bus voltage.

[0055] In a preferred embodiment of the present invention, the voltage difference between the inside and outside of the battery refers to the absolute value of the difference between the internal battery voltage and the external battery voltage. Alternatively, the DC bus capacitor voltage can be monitored instead of the DC bus voltage to determine whether the DC bus capacitor has completed pre-charging. It is understood that the DC bus capacitor voltage refers to the voltage across the capacitor, which is usually similar to the bus voltage, but may differ slightly due to the energy storage and filtering effects of the capacitor.

[0056] Secondly, in this embodiment, since the current acquisition function of the battery management system (BMS) is required when monitoring the voltage difference between the inside and outside of the battery and the DC bus voltage, this embodiment also optimizes the protection circuit of the current acquisition to prevent damage to the components of the current acquisition circuit caused by the surge voltage due to the BMS's misjudgment of pre-charge. For example... Figure 3 As shown, based on the original current acquisition circuit, the current acquisition port protection circuit is enhanced by using high-voltage, high-power protection devices, such as transient voltage suppressors (TVS) and gas plasma protectors, to achieve rapid protection of the current acquisition circuit and improve the circuit's electrostatic discharge and surge protection capabilities. A filtering stage is added to the current acquisition circuit to optimize the circuit layout, reduce circuit impedance, and reduce the impact of large surge voltages on the circuit. This ensures that the devices in the current acquisition circuit are not damaged during large surge voltage impacts, thus preventing current acquisition failure.

[0057] Preferably, determining whether the DC bus capacitor has completed pre-charging based on the voltage difference between the inside and outside of the battery and the DC bus voltage includes:

[0058] S41. When it is determined that the first maintenance time for the voltage difference between the inside and outside of the battery is less than the second preset voltage is not less than the first preset time, and the DC bus voltage is within the range of the first preset voltage, the DC bus capacitor is confirmed to be pre-charged.

[0059] In a preferred embodiment of the present invention, the second preset voltage is set to 7V and the first preset duration is set to 120ms. The pre-charging of the DC bus capacitor is confirmed to be complete only when the voltage difference between the inside and outside of the battery is monitored and the voltage difference between the inside and outside of the battery is maintained at 7V for a duration greater than 120ms, and the DC bus voltage is within the range of the first preset voltage. Compared with the prior art, which only uses the DC bus voltage as a single judgment condition to determine whether the pre-charging is complete, this embodiment adds the judgment of the voltage difference between the inside and outside of the battery to reduce the false judgment rate of the BMS.

[0060] Preferably, the step of determining whether the DC bus capacitor has been pre-charged based on the voltage difference between the inside and outside of the battery and the DC bus voltage further includes:

[0061] S42. When it is determined that the second maintenance time is not less than the second preset time and the voltage difference between the inside and outside of the battery is not less than the second preset voltage, the DC bus capacitor pre-charge is confirmed to have failed.

[0062] In a preferred embodiment of the present invention, the second preset duration is set according to the normal pre-charge duration of the DC bus capacitor. It can be understood that when it is detected that the voltage difference between the inside and outside of the battery cannot be lower than the second preset voltage for a long time after the pre-charge should have been completed, it can be determined that the pre-charge has failed and the steps S461-S463 are used for processing.

[0063] Preferably, the step of determining whether the DC bus capacitor has been pre-charged based on the voltage difference between the inside and outside of the battery and the DC bus voltage further includes:

[0064] S43. When it is determined that the first maintenance time for which the voltage difference between the inside and outside of the battery is less than the second preset voltage is not less than the first preset time, and the DC bus voltage is not within the range of the first preset voltage, the second output voltage of the charger is obtained.

[0065] S44. Determine whether the second output voltage is within the second preset voltage range;

[0066] S45. If yes, then confirm that the DC bus capacitor pre-charge is complete;

[0067] S46. If not, then confirm that the DC bus capacitor pre-charge has failed.

[0068] In a preferred embodiment of the present invention, since the charger is a power supply device, its main function is to provide electrical energy to batteries or other energy storage devices. During the charging process, the charger adjusts its output voltage and current according to the needs of the charging equipment. This output voltage is an important indicator of the electrical energy characteristics output by the charger. Therefore, when the charger supplies power to the bus and its connected equipment, if the load is stable and there are no other external interferences, the voltage of the bus capacitor may be close to or equal to the output voltage of the charger. Therefore, this embodiment further confirms the DC bus voltage by detecting the second output voltage of the charger, and then determines whether the DC bus capacitor has completed pre-charging. This further improves the accuracy of the BMS pre-charging completion determination.

[0069] Preferably, after confirming that the DC bus capacitor pre-charging has failed, the method further includes:

[0070] S461. Disconnect the pre-charge relay and obtain the pre-charge failure count;

[0071] S462. When it is determined that the precharge failure count is less than a preset number threshold, the precharge failure count is incremented by one, and after a preset waiting time, the precharge relay is closed again.

[0072] S463. When it is determined that the precharge failure count is not less than a preset number threshold, a precharge failure alarm is issued.

[0073] In a preferred embodiment of the present invention, when pre-charging fails, the pre-charging relay needs to be disconnected and a pre-charging failure count needs to be performed. The pre-charging process should be retried after at least 400ms, and the count should be cleared if successful. If more than 4 failures occur, the BMS sends a pre-charging failure alarm to the vehicle. At this time, the BMS needs to shut down all drive circuits and continuously monitor the cell voltage and cell temperature, etc.

[0074] S5. When it is confirmed that the DC bus capacitor pre-charge is complete, control the pre-charge relay to open and control the main positive relay to close.

[0075] This embodiment provides a pre-charge control method for a vehicle battery management system. Upon receiving a high-voltage power-on command, the method acquires the starting power supply voltage and the first output voltage of the DC-DC converter. When the first output voltage or the starting power supply voltage is determined to be greater than a first preset voltage, the pre-charge relay is closed to pre-charge the DC bus capacitor. Therefore, this invention effectively ensures the safety of the vehicle during high-voltage power-on. Furthermore, by simultaneously monitoring the voltage difference between the battery's internal and external components and the DC bus voltage during pre-charge, the method determines whether the DC bus capacitor has been pre-charged. This avoids the DC bus voltage being affected when the vehicle system is undervoltage, which could lead to the BMS misjudging pre-charge completion. This effectively reduces the risk of BMS misjudgment, prevents the current acquisition circuit from being impacted by large surges, enhances the reliability and stability of the battery management system, and improves the safety performance of electric vehicles.

[0076] See Figure 2 This is a schematic diagram of the structure of a pre-charge control device for a vehicle battery management system according to an embodiment of the present invention, comprising:

[0077] The instruction acquisition module is used to acquire high-voltage power-on instructions;

[0078] The voltage acquisition module is used to acquire the startup power supply voltage and the first output voltage of the DC-DC converter according to the high voltage power-on command.

[0079] The precharge execution module is used to close the precharge relay when it is determined that the first output voltage or the starting power supply voltage is greater than the first preset voltage, so as to precharge the DC bus capacitor.

[0080] The pre-charge monitoring module is used to monitor the voltage difference between the inside and outside of the battery and the DC bus voltage, and to determine whether the DC bus capacitor has been pre-charged based on the voltage difference between the inside and outside of the battery and the DC bus voltage.

[0081] The pre-charge completion module is used to control the pre-charge relay to open and the main positive relay to close when it is confirmed that the DC bus capacitor has been pre-charged.

[0082] Preferably, the pre-charge monitoring module determines whether the DC bus capacitor has completed pre-charging based on the voltage difference between the inside and outside of the battery and the DC bus voltage, including:

[0083] When the voltage difference between the inside and outside of the battery is less than the second preset voltage for a first maintenance time that is not less than the first preset time, and the DC bus voltage is within the range of the first preset voltage, the DC bus capacitor is confirmed to be pre-charged.

[0084] Preferably, the pre-charge monitoring module, which determines whether the DC bus capacitor has completed pre-charging based on the voltage difference between the inside and outside of the battery and the DC bus voltage, further includes:

[0085] When the second maintenance duration is determined to be no less than the second preset duration and the voltage difference between the inside and outside of the battery is no less than the second preset voltage, the pre-charging of the DC bus capacitor is confirmed to have failed.

[0086] It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0087] Those skilled in the art will clearly understand that, for convenience and brevity, the specific working process of the device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0088] Another preferred embodiment of the present invention provides a terminal device including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements a pre-charge control method for a vehicle battery management system as described in any of the above embodiments.

[0089] The terminal device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0090] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the terminal device, connecting all parts of the terminal device via various interfaces and lines.

[0091] The memory can be used to store the computer program. The processor implements various functions of the terminal device by running or executing the computer program stored in the memory and calling data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function, etc.; the data storage area may store data created based on the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0092] Another preferred embodiment of the present invention provides a storage medium, which is a computer-readable storage medium. A computer program is stored in the computer-readable storage medium, and when executed by a processor, the computer program can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0093] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A pre-charge control method for a vehicle battery management system, applied to a high-voltage system of an electric vehicle comprising a high-voltage power battery, a low-voltage start-up battery, a pre-charge relay, a main positive relay, a DC bus capacitor, and a DC-DC converter, characterized in that, include: Receive high-voltage power-on command; According to the high-voltage power-on command, the startup power supply voltage and the first output voltage of the DC-DC converter are obtained; wherein, the startup power supply voltage is the voltage of the low-voltage startup battery; When it is determined that the first output voltage or the starting power supply voltage is greater than the first preset voltage, the pre-charge relay is closed so that the high-voltage power battery pre-charges the DC bus capacitor. Monitor the voltage difference between the inside and outside of the battery and the DC bus voltage, and determine whether the DC bus capacitor has been pre-charged based on the voltage difference between the inside and outside of the battery and the DC bus voltage; wherein, the voltage difference between the inside and outside of the battery is the absolute value of the difference between the internal voltage and the external voltage of the high-voltage power battery; When the pre-charging of the DC bus capacitor is confirmed to be complete, the pre-charging relay is controlled to open, and the main positive relay is controlled to close. The determination of whether the DC bus capacitor has completed pre-charging, based on the voltage difference between the inside and outside of the battery and the DC bus voltage, includes: When the first maintenance time for which the voltage difference between the inside and outside of the battery is less than the second preset voltage is not less than the first preset time, and the DC bus voltage is within the range of the first preset voltage, the pre-charging of the DC bus capacitor is confirmed to be complete. When the second maintenance duration is determined to be no less than the second preset duration and the voltage difference between the inside and outside of the battery is no less than the second preset voltage, the pre-charging of the DC bus capacitor is confirmed to have failed.

2. The pre-charge control method for a vehicle battery management system as described in claim 1, characterized in that, The step of determining whether the DC bus capacitor has completed pre-charging based on the voltage difference between the inside and outside of the battery and the DC bus voltage further includes: When the first maintenance time for which the voltage difference between the inside and outside of the battery is less than the second preset voltage is not less than the first preset time, and the DC bus voltage is not within the range of the first preset voltage, the second output voltage of the on-board charger is obtained. Determine whether the second output voltage is within the second preset voltage range; If so, then confirm that the DC bus capacitor pre-charging is complete; If not, then the DC bus capacitor pre-charge has failed.

3. The pre-charge control method for a vehicle battery management system as described in claim 2, characterized in that, After confirming that the DC bus capacitor pre-charging has failed, the process also includes: Disconnect the precharge relay and obtain the precharge failure count; When the precharge failure count is determined to be less than a preset number of times, the precharge failure count is incremented by one, and after a preset waiting time, the precharge relay is closed again. When the precharge failure count is determined to be not less than a preset threshold number, a precharge failure alarm is issued.

4. A pre-charge control device for a vehicle battery management system, applied to a high-voltage system of an electric vehicle including a high-voltage power battery, a low-voltage start-up battery, a pre-charge relay, a main positive relay, a DC bus capacitor, and a DC-DC converter, characterized in that, include: The instruction acquisition module is used to acquire high-voltage power-on instructions; The voltage acquisition module is used to acquire the startup power supply voltage and the first output voltage of the DC-DC converter according to the high-voltage power-on command; wherein, the startup power supply voltage is the voltage of the low-voltage startup battery; The precharge execution module is used to close the precharge relay when it is determined that the first output voltage or the starting power supply voltage is greater than the first preset voltage, so that the high-voltage power battery precharges the DC bus capacitor. The pre-charge monitoring module is used to monitor the voltage difference between the inside and outside of the battery and the DC bus voltage, and to determine whether the DC bus capacitor has been pre-charged based on the voltage difference between the inside and outside of the battery and the DC bus voltage; wherein, the voltage difference between the inside and outside of the battery is the absolute value of the difference between the internal voltage and the external voltage of the high-voltage power battery; The pre-charge completion module is used to control the pre-charge relay to open and the main positive relay to close when it is confirmed that the DC bus capacitor has been pre-charged. The determination of whether the DC bus capacitor has completed pre-charging, based on the voltage difference between the inside and outside of the battery and the DC bus voltage, includes: When the first maintenance time for which the voltage difference between the inside and outside of the battery is less than the second preset voltage is not less than the first preset time, and the DC bus voltage is within the range of the first preset voltage, the pre-charging of the DC bus capacitor is confirmed to be complete. When the second maintenance duration is determined to be no less than the second preset duration and the voltage difference between the inside and outside of the battery is no less than the second preset voltage, the pre-charging of the DC bus capacitor is confirmed to have failed.

5. A terminal device, characterized in that, The system includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements a pre-charge control method for a vehicle battery management system as described in any one of claims 1 to 3.

6. A storage medium, characterized in that, The storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device where the storage medium is located to perform a pre-charge control method for a vehicle battery management system as described in any one of claims 1 to 3.

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