Automobile production line writing loss prevention high voltage maintenance method and system

Abstract

The present application belongs to the technical field of new energy automobile production testing, and particularly relates to a method and system for preventing loss of electricity during high-voltage maintenance in automobile production line writing. The method comprises the following steps: BMS detects preset production line environment signals to determine whether the vehicle is in the production line writing station; BMS detects three trigger conditions, including receiving an entering communication mute mode instruction, not receiving a periodic high-voltage maintenance message within a preset time threshold, and determining that the high-voltage main contactor is in the attracted state; when all three trigger conditions are met, BMS continues to output excitation current to the drive circuit of the high-voltage main contactor to keep the high-voltage main contactor attracted; and the DC-DC converter converts the output voltage of the high-voltage main contactor to supply power to the vehicle ECU. The present application adopts a three-condition trigger mode based on UDS communication mute, designs a production line special mode entering / leaving mechanism and a control right transfer mechanism, and uses the vehicle's own high-voltage system to supply power to the whole vehicle during UDS writing mute.

Description

Technical Field

[0001] This invention belongs to the field of new energy vehicle production and testing technology, and in particular relates to a method and system for maintaining high voltage to prevent power loss in automobile production lines. Background Technology

[0002] In the production line of new energy vehicles, multiple electronic control units (ECUs) need to be flashed using the UDS protocol. During the UDS flashing process, to ensure network communication quality, a $28 service is used to put unrelated ECUs into a "communication silence" state to reduce bus load.

[0003] Upon receiving the $28 instruction, the BMS will also enter a silent state, disconnecting the main contactor of the high-voltage system and causing the high-voltage system to lose power. The ensuing problem is that the DC-DC converter, which converts high-voltage electricity to 12V low-voltage electricity to charge the battery, stops working after the high-voltage power is cut off because its power source is high-voltage electricity.

[0004] With the popularization of automotive intelligence, the number of vehicle controllers has surged, and the number of controllers for production line flashing has also surged, resulting in a continuous increase in flashing time. During the flashing process, the entire vehicle ECU is powered only by a 12V battery, which can easily lead to battery depletion, causing flashing interruption, affecting production efficiency, and in severe cases, damaging the ECU. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a method and system for maintaining high voltage during UDS writing to prevent power loss in automotive production lines. It adopts a triple-condition triggering mode based on UDS communication silence, and designs a production line-specific mode entry / exit mechanism and control transfer mechanism. In the triple-condition triggering mode, the BMS maintains the previous working state after silence, continues to provide excitation current to the high-voltage main contactor, and keeps it engaged. No external power protection equipment is required. The vehicle's own high-voltage system supplies power to the whole vehicle during the UDS writing silence period.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: The first aspect of this invention provides a method for maintaining high voltage to prevent power loss during brushing in an automotive production line.

[0007] The method for maintaining high voltage to prevent battery drain on automotive production lines includes the following steps: BMS detects preset production line environment signals to determine if the vehicle is at the production line writing station; The BMS detects three trigger conditions, including receiving a command to enter the communication silent mode, not receiving a periodic high voltage maintenance message within a preset time threshold, and determining that the high voltage main contactor is in the energized state. Once all three triggering conditions are met, the BMS continues to output excitation current to the drive circuit of the high-voltage main contactor to keep the high-voltage main contactor engaged. The DC-DC converter converts the output voltage of the high-voltage main contactor to power the entire vehicle's ECU, thus maintaining high voltage during the production line's flashing process.

[0008] As a preferred technical solution, the production line environment signals include diagnostic equipment connection signals, vehicle stationary status signals, and gear position in P (Park) signals, wherein: The diagnostic device connection signal is obtained by detecting the physical connection status of the diagnostic interface; The vehicle stationary state signal is obtained by detecting a vehicle speed of zero using a vehicle speed sensor. The gear position signal (P gear) is obtained by detecting the gear position status through a gear position sensor.

[0009] As a preferred technical solution, the preset time threshold is a set multiple of the transmission period of the periodic high-voltage maintenance message.

[0010] As a preferred technical solution, the BMS continues to output excitation current to the drive circuit of the high-voltage main contactor by maintaining the conduction state of the drive circuit and continuously outputting current to the drive coil of the high-voltage main contactor.

[0011] As a preferred technical solution, the DC-DC converter converts the output voltage of the high-voltage main contactor to power the entire vehicle's ECU. The specific process is as follows: When the high voltage detection circuit of the DC-DC converter detects that the high voltage at the input terminal is greater than the preset start-up voltage threshold and the duration exceeds the preset time threshold, the voltage conversion circuit is activated. The voltage conversion circuit converts high-voltage electricity into low-voltage electricity and outputs it to the 12V mains. High-voltage electricity is transmitted via the high-voltage main contactor to the DC-DC converter and the 12V power grid, reaching the entire vehicle ECU and forming a power supply closed loop. Also includes: The BMS monitors the 12V mains voltage in real time. When it detects that the 12V mains voltage is lower than a preset protection threshold, it sends an alarm signal to the diagnostic device. While maintaining the high-voltage main contactor engaged, the BMS continuously monitors the insulation resistance of the high-voltage system. When the insulation resistance is detected to be lower than a preset safety threshold, the BMS immediately stops outputting excitation current to the drive circuit of the high-voltage main contactor and disconnects the high-voltage main contactor.

[0012] As a preferred technical solution, the following are also included: After the flashing is completed, the diagnostic device sends an exit quiz command and a controller reset command. The VCU or FLZCU is woken up and resends the network management message and high voltage control command. When the BMS detects that the VCU or FLZCU has resumed normal communication, it stops the autonomous control logic that outputs excitation current to the drive circuit of the high-voltage main contactor and resumes the working mode of controlling the high-voltage main contactor according to the high-voltage control command sent by the VCU or FLZCU.

[0013] As a preferred technical solution, the BMS detects that the VCU or FLZCU has resumed normal communication under the following condition: continuously receiving the periodic high-voltage maintenance message sent by the VCU or FLZCU within a preset time window.

[0014] The second aspect of the present invention provides a high-voltage maintenance system for preventing power loss during brushing in automotive production lines.

[0015] Automotive production line flashing of anti-power loss high voltage maintenance system includes: The production line environment recognition module is configured to: detect preset production line environment signals in the BMS and determine that the vehicle is in the production line writing station; The trigger condition detection module is configured to: detect three trigger conditions in the BMS, including receiving a command to enter the communication silent mode, not receiving a periodic high voltage maintenance message within a preset time threshold, and determining that the high voltage main contactor is in the energized state. The engagement control module is configured such that when all three trigger conditions are met, the BMS continues to output excitation current to the drive circuit of the high-voltage main contactor to keep the high-voltage main contactor engaged. The high-voltage maintenance module is configured as follows: the DC-DC converter converts the output voltage of the high-voltage main contactor to power the entire vehicle ECU, thereby maintaining high voltage during the production line flashing process.

[0016] A third aspect of the present invention provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the steps of the method for maintaining high voltage to prevent power loss on an automotive production line as described in the first aspect of the present invention.

[0017] The fourth aspect of the present invention provides an electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the method for maintaining high voltage to prevent power loss on an automotive production line as described in the first aspect of the present invention.

[0018] The above one or more technical solutions have the following beneficial effects: This invention provides a method and system for maintaining high voltage during automotive production line flashing to prevent battery drain. By adding production line-specific logic to the BMS after the UDS $28 service network is silenced, it maintains the previous operating state after silence, bypassing VCU / FLZCU instructions and autonomously maintaining the high voltage system. This method solves the problem of 12V battery drain caused by communication silence during production line flashing, eliminates the need for an external high-power power supply, simplifies production line steps, improves production cycle time, avoids flashing failures due to poor external power supply contact, and increases production line first-pass yield.

[0019] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 This is a schematic diagram of an example environment that can be implemented according to Embodiment 1 of the present invention.

[0022] Figure 2 This is a flowchart illustrating the power-saving method provided in Embodiment 1 of the present invention.

[0023] Figure 3 This is a flowchart of the triple condition detection process of the BMS logic judgment unit in Embodiment 1 of the present invention.

[0024] Figure 4 This is a schematic diagram of the power supply closed loop in Embodiment 1 of the present invention. Detailed Implementation

[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, 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 invention pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0027] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0028] Terminology Explanation To facilitate understanding of the technical solution of this invention, the core technical terms involved in this invention will first be defined and explained: UDS, short for Unified Diagnostic Services, is a vehicle diagnostic communication protocol defined by the ISO 14229 standard, used for data exchange between diagnostic equipment and vehicle ECUs.

[0029] Service $28, or CommunicationControl in the UDS protocol, is used to control the communication behavior of the ECU. In this invention, when the diagnostic device sends the 0x28 01 command, the target ECU enters a communication silence mode, stops sending regular messages, and only retains the diagnostic communication channel.

[0030] BMS, short for Battery Management System, is responsible for monitoring and managing the status of the power battery, including parameters such as battery voltage, current, temperature, and SOC (State of Charge), and controlling the on / off state of the high-voltage main contactor.

[0031] VCU, short for Vehicle Control Unit, is the core control unit of new energy vehicles, responsible for functions such as vehicle energy management, driving mode control, and high-voltage system power-on / off management. In normal operating mode, the VCU periodically sends high-voltage maintenance messages to the BMS via the CAN bus, instructing the BMS to keep the high-voltage main contactor engaged.

[0032] FLZCU, short for Front Left Zone Control Unit, replaces the VCU in some vehicle architectures to perform vehicle control functions. It has the same functional positioning as the VCU in terms of high-voltage control logic. In this invention, the expression "VCU or FLZCU" refers to the main body that performs vehicle control functions, and is not limited to a specific controller form.

[0033] The high-voltage main contactor is a key switching device connecting the high-voltage battery to the vehicle's high-voltage power grid. It typically consists of a positive contactor and a negative contactor. Internally, the contactor contains a drive coil and contacts. When the drive coil is energized and generates a magnetic field, the contacts close, and the high-voltage circuit is connected. When the drive coil is de-energized, the contacts open under the force of a spring, and the high-voltage circuit is disconnected.

[0034] A DC-DC converter, also known as a direct current to direct current voltage converter, is a power conversion device used in new energy vehicles to convert the high-voltage direct current (e.g., 300V-800V) from the high-voltage battery into low-voltage direct current (e.g., 12V or 24V), supplying power to the vehicle's low-voltage electrical equipment and charging the 12V battery.

[0035] Magnetizing current refers to the current flowing through the drive coil of the high-voltage main contactor. This current generates a magnetic field in the coil, driving the contacts to close. In this invention, the BMS continuously outputs magnetizing current to the drive coil by controlling the conduction state of the drive circuit, thereby maintaining the closed state of the high-voltage main contactor.

[0036] Production line environmental signals refer to a set of characteristic signals used to determine whether a vehicle is at a production line writing station. These signals include diagnostic equipment connection signals, vehicle stationary status signals, and gear position in Park (P) signals. The combination of these signals characterizes the typical operating conditions of the production line writing process, which are significantly different from normal driving or other operating conditions.

[0037] Technical Background and Problem Definition In the production of new energy vehicles, the software reprogramming station on the production line is a crucial step before the vehicle rolls off the assembly line. At this station, multiple electronic control units (ECUs) inside the vehicle need to be reprogrammed using the UDS diagnostic protocol to ensure that each ECU runs the latest version of its control program.

[0038] According to the UDS protocol specification, in order to ensure the communication quality of the CAN bus during the flashing process, the diagnostic equipment will send a 0x28 service command to the vehicle after entering the flashing session. This will cause ECUs unrelated to flashing to enter a communication silent mode and stop sending regular messages, thereby reducing the bus load and avoiding message conflicts that could interfere with the flashing data transmission.

[0039] However, a key technical flaw exists in the existing technology: as the manager of the vehicle's high-voltage system, the BMS will also enter a communication silence state upon receiving the $28 service command. At this time, according to conventional logic, the BMS will disconnect the high-voltage main contactor, causing the high-voltage system to lose power. The direct consequence of the high-voltage system losing power is that the DC-DC converter loses its input power and stops working, unable to continue supplying power to the 12V mains.

[0040] As automotive intelligence increases, the number of ECUs (Electronic Control Units) in vehicles is growing exponentially, leading to a surge in the number of controllers and the duration of flashing processes. During these lengthy flashing processes, all ECUs rely solely on a 12V battery for power, and this battery has limited capacity, making it prone to depletion. If the 12V mains voltage drops below the ECU's operating voltage limit, the flashing process will fail, causing rework and impacting production efficiency. In more severe cases, excessively low voltage can damage the data in the ECU's internal memory, rendering the hardware unusable.

[0041] To address the aforementioned issues, the existing technology typically employs a high-power DC programmable power supply at each writing station on the production line. The output of this power supply is connected to the positive and negative terminals of the vehicle's 12V battery via a power clamp, simulating a continuously existing generator to provide continuous power to the entire vehicle.

[0042] However, this external power supply solution has significant technical and economic drawbacks: First, capital expenditure is high. High-power programming power supplies are expensive per unit, and a complete production line usually includes dozens of writing stations, requiring the purchase of dozens to hundreds of power supply devices, resulting in extremely high total investment costs.

[0043] Secondly, operation and maintenance are complex. The power supply equipment itself requires regular maintenance and calibration, and the connecting cables and power clamps are vulnerable parts. Frequent plugging and unplugging can lead to poor contact, increasing operating costs and potential points of failure.

[0044] Third, the workstations occupy a large amount of space. The large power supply equipment makes the production line layout crowded, affecting the working space and the aesthetics of the production line.

[0045] Fourth, the operation process is cumbersome. Production line workers need to connect and disconnect the power clamps for each vehicle, which increases operating time and poses a risk of human error, such as reversing the power polarity, which may damage the vehicle's electrical system.

[0046] Therefore, there is an urgent need for a technical solution that can power the entire vehicle using the vehicle's own energy system during the UDS flashing silent period without the need for external power supply equipment, so as to fundamentally solve the above-mentioned technical problems.

[0047] Overview of Technical Implementation Approach The core concept of this invention is "special handling for special cases," that is, for the special working condition of production line writing, a special power protection logic for the production line is pre-embedded in the BMS. When it detects that the UDS communication is in a silent state and the production line environmental signal is met, it will not execute the conventional high-voltage power-off procedure triggered by the loss of VCU or FLZCU commands. Instead, it will autonomously maintain the high-voltage main contactor in the energized state, bypass the control commands of VCU or FLZCU, and continue to supply power to the high-voltage system.

[0048] Specifically, this invention adds a triple condition detection mechanism to the BMS: First, the 0x28 service command sent by the diagnostic device is received via the CAN bus, confirming that the vehicle network has entered communication silent mode; Second, if no periodic high-voltage maintenance message is received from VCU or FLZCU within the preset time threshold, it is confirmed that VCU or FLZCU has entered a silent state. Third, by detecting the engagement feedback signal of the high-voltage main contactor, it can be confirmed that the high-voltage system was in working condition before the shutdown.

[0049] When the above three conditions are met simultaneously, and the BMS detects that the vehicle is in the production line environment, including when the diagnostic equipment is connected, the vehicle is stationary, and the gear is in P, the BMS logic judgment unit triggers the production line power protection logic, continues to output excitation current to the drive circuit of the high-voltage main contactor, keeps the contactor engaged, and enables the high-voltage system to continue to work.

[0050] At the same time, when the high voltage detection circuit of the DC-DC converter detects that the high voltage at the input terminal is greater than the preset start-up voltage threshold and the duration exceeds the preset time threshold, it automatically starts the voltage conversion circuit to convert the high voltage to low voltage and output it to the 12V power grid to power the entire vehicle ECU.

[0051] Thus, the vehicle has formed a self-sufficient power supply closed loop, such as... Figure 4 As shown: High-voltage battery → High-voltage main contactor → DC-DC converter → 12V power grid → Vehicle ECU. The entire flashing process is completed stably with the support of the vehicle's own power.

[0052] After the flashing process is complete, the diagnostic equipment sends a 0x28 00 exit quiescent command and a 0x11 01 controller reset command. The VCU or FLZCU is awakened and resends network management messages and high-voltage control commands. The BMS detects that the VCU or FLZCU has resumed normal communication, stops the production line power supply logic, and returns high-voltage control to the VCU or FLZCU. The vehicle then returns to normal operating mode.

[0053] The essential difference between this invention and existing technologies is that existing technologies rely on external power supply equipment to power vehicles, while this invention utilizes the vehicle's own high-voltage system and energy management logic to achieve autonomous power supply during the production line writing process through intelligent control at the software level. This eliminates the need for any additional external hardware equipment and fundamentally solves the problems of cost, maintenance, space, and operational complexity associated with existing technologies.

[0054] Example Environment Description Figure 1 Schematic diagrams are shown illustrating example environments in which various embodiments of this disclosure can be implemented. For example... Figure 1 As shown, this example environment consists of two main parts: the production line flashing station and the vehicle's internal systems.

[0055] The software flashing station on the production line includes diagnostic equipment and the vehicle to be flashed. The diagnostic equipment is typically a specialized automotive diagnostic tool or a flashing system integrated into the production line. It physically connects to the vehicle's OBD interface via a diagnostic interface, establishing a UDS diagnostic communication channel. The functions of the diagnostic equipment include: sending UDS diagnostic commands, reading ECU information, performing software flashing, monitoring flashing progress, and handling flashing anomalies.

[0056] The vehicle's internal systems include BMS101, VCU or FLZCU102, high-voltage main contactor 103, DC-DC converter 104, 12V power grid 105, and all vehicle ECUs 106. These devices are interconnected via CAN bus 107 and power lines 108, forming the vehicle's energy management and control network.

[0057] BMS101 is the core execution unit of this invention, responsible for monitoring and managing the status of the high-voltage battery 109, controlling the on / off state of the high-voltage main contactor 103, and executing the production line power supply logic. BMS101 communicates with VCU or FLZCU102 and diagnostic equipment via CAN bus 107, receives high-voltage control commands and diagnostic commands, and sends battery status information to other controllers.

[0058] In normal operating mode, the VCU or FLZCU102 is responsible for vehicle energy management and high-voltage system control. It periodically sends high-voltage maintenance messages to the BMS101 via the CAN bus 107, instructing the BMS101 to keep the high-voltage main contactor 103 engaged. During the production line flashing process, when the VCU or FLZCU102 receives the 0x28 service command, it enters a communication silence state and stops sending high-voltage maintenance messages.

[0059] The high-voltage main contactor 103 is a key switching device connecting the high-voltage battery 109 to the vehicle's high-voltage power grid, and is controlled by the BMS101 through a drive circuit. The high-voltage main contactor 103 typically includes a positive contactor, a negative contactor, a pre-charge resistor, and a pre-charge contactor. During the normal power-on process, the BMS101 first closes the pre-charge contactor, slowly charging the high-voltage power grid through the pre-charge resistor. Once the grid voltage reaches a certain proportion of the battery voltage, the main contactor closes, completing the high-voltage power-on process.

[0060] The input terminal of the DC-DC converter 104 is connected to the high-voltage battery 109 via a high-voltage main contactor 103, and the output terminal is connected to the 12V power grid 105. The function of the DC-DC converter 104 is to convert the high-voltage DC power (e.g., 400V) from the high-voltage battery 109 to a low-voltage DC power (e.g., 13.5V) to power the 12V power grid 105 and charge the 12V battery. The DC-DC converter 104 internally includes a high-voltage detection circuit, a start-up control circuit, a voltage conversion circuit, and an output circuit. It can automatically detect the high-voltage input and automatically start operation when the start-up conditions are met.

[0061] The 12V mains 105 supplies power to all low-voltage electrical equipment in the vehicle, including the ECUs 106, lighting system, air conditioning system, multimedia system, etc. The 12V mains 105 is typically powered by both the 12V battery and the DC-DC converter 104. When the vehicle is in normal operation, the DC-DC converter 104 is the primary power source, and the battery is the auxiliary power source; when the vehicle is stationary or the high-voltage system is powered down, the battery is the sole power source.

[0062] The entire vehicle's ECU106 includes multiple electronic control units such as the powertrain domain controller, chassis domain controller, body domain controller, and smart cockpit controller, numbering from dozens to hundreds. During the production line flashing process, these ECUs require continuous power to maintain flashing communication and program writing.

[0063] The interaction logic between the devices is as follows: In normal operating mode, VCU or FLZCU102 periodically sends high-voltage maintenance messages to BMS101 via CAN bus 107. BMS101 controls the high-voltage main contactor 103 to remain engaged according to the message. The high-voltage battery 109 supplies power to the DC-DC converter 104 through the high-voltage main contactor 103. The DC-DC converter 104 converts the high-voltage electricity into low-voltage electricity and outputs it to the 12V power grid 105 to supply power to the entire vehicle ECU 106.

[0064] During the production line flashing process, when the diagnostic equipment sends the 0x28 service command, the VCU or FLZCU102 enters a silent state and stops sending high-voltage maintenance messages. When the BMS101 detects that the message is lost and the production line environmental conditions are met, it triggers the production line power supply logic, autonomously maintaining the high-voltage main contactor 103 to engage. The DC-DC converter 104 detects that the high voltage is continuously present and automatically starts working to continue supplying power to the 12V power grid 105, ensuring the power supply needs of the entire vehicle ECU 106 during the flashing process.

[0065] In terms of communication, the BMS101, VCU or FLZCU102, and all vehicle ECUs106 communicate via the CAN bus107. The CAN bus107 typically uses two-wire differential signal transmission, which has strong anti-interference capabilities and real-time performance. The diagnostic equipment connects to the vehicle's CAN bus107 through the diagnostic interface, sends UDS diagnostic commands, and receives response messages from the ECUs.

[0066] Regarding the expandability of the device, the technical solution of this invention is not limited to... Figure 1The specific device configurations shown are as follows. For example, BMS101 can be a standalone battery management controller or integrated with the battery pack; VCU or FLZCU102 can be a standalone vehicle controller or integrated with the power domain controller or chassis domain controller; DC-DC converter 104 can be a standalone converter module or integrated with the on-board charger OBC as a two-in-one or three-in-one power module.

[0067] In terms of scenario scalability, the technical solution of this invention is not only applicable to production line writing stations, but can also be extended to after-sales maintenance scenarios. During after-sales maintenance, when technicians use diagnostic equipment to upgrade vehicle software or diagnose faults, they may encounter the problem of UDS communication silence causing the high-voltage system to shut down. By pre-embedding after-sales power-saving logic in the BMS101, a similar power-saving mechanism can be triggered when after-sales environmental signals such as maintenance mode activation or diagnostic equipment connection are detected, preventing the 12V battery from running out of power during maintenance.

[0068] Regarding compliance, the technical solution of this invention must comply with relevant automotive electrical safety standards during implementation, including ISO 26262 functional safety standard and GB / T 18384 safety requirements for new energy vehicles. When executing the production line power protection logic, BMS101 must continuously monitor safety parameters such as the insulation resistance of the high-voltage system, contactor status, and battery temperature. If any abnormality is detected, it should immediately exit the power protection mode and disconnect the high-voltage main contactor 103 to ensure the safety of personnel and equipment.

[0069] It should be understood that Figure 1 The example environments shown are for illustrative purposes only and do not constitute a limitation on the scope of protection of this invention. Those skilled in the art can adjust and optimize the device configuration, communication methods, control logic, etc., according to actual application needs. Any adjustments and optimizations made that conform to the core technical concept of this invention should fall within the scope of protection of this invention.

[0070] Example 1 In the background technology, when a vehicle enters an extended session or a flashing session, it follows the UDS standard to enter a $28 communication silent mode, causing the high-voltage system to shut down and the DC-DC converter to stop working. Furthermore, since the entire vehicle's ECU is powered only by a 12V battery, this easily leads to battery depletion, causing flashing interruptions, impacting production efficiency, and in severe cases, damaging the ECU. This forces the production line to provide an additional high-power low-voltage power supply for the vehicle to prevent 12V battery depletion during flashing, increasing production line costs and complexity.

[0071] In existing technologies, to address the aforementioned issues, a high-power DC programmable power supply is typically configured at each writing station on the production line, with its output directly connected to the vehicle's 12V battery to simulate a continuously operating generator. However, this solution has the following drawbacks: high capital expenditure, requiring the purchase of dozens to hundreds of programmable power supplies, resulting in extremely high total costs; complex operation and maintenance, as the power supply equipment itself requires maintenance and calibration, and the connecting cables and connectors are easily damaged, increasing operating costs and potential points of failure; large workstation space occupation, with the bulky power supply equipment making the production line layout crowded and affecting workspace; and cumbersome operation procedures, requiring workers to connect and disconnect the power supply clamps for each vehicle, increasing operating time and the risk of human error.

[0072] This embodiment discloses a high-voltage maintenance method for preventing battery drain during automotive production line brushing. A production line-specific mode is pre-embedded in the BMS or a specific collaborative controller. When a 28V silent state is detected and the production line environmental signals are met, the BMS autonomously maintains the high-voltage contactor engaged and instructs the DC-DC converter to continue operating, supplying power to the 12V grid. This solves the technical problems in existing technologies where the BMS entering communication silence during production line brushing causes the high-voltage system to shut down, the DC-DC converter to stop working, and the 12V battery to drain, leading to brushing interruptions and reduced production efficiency. It also addresses the high capital expenditure, complex operation and maintenance, large workstation space occupation, and cumbersome operation procedures of existing external power protection solutions.

[0073] The method for maintaining high voltage to prevent battery drain on automotive production lines includes the following steps: BMS detects preset production line environment signals to determine if the vehicle is at the production line writing station; The BMS detects three trigger conditions, including receiving a command to enter the communication silent mode, not receiving a periodic high voltage maintenance message within a preset time threshold, and determining that the high voltage main contactor is in the energized state. Once all three triggering conditions are met, the BMS continues to output excitation current to the drive circuit of the high-voltage main contactor to keep the high-voltage main contactor engaged. The DC-DC converter converts the output voltage of the high-voltage main contactor to power the entire vehicle's ECU, thus maintaining high voltage during the production line's flashing process.

[0074] Specifically: In this embodiment of the invention, at the production line's writing station, the diagnostic equipment sends a 0x28 service command to the vehicle via the UDS protocol, causing the vehicle's network to enter a communication silent mode. BMS detects preset production line environment signals to determine that the vehicle is in the production line writing station. The production line environment signals include diagnostic equipment connection signals, vehicle stationary status signals, and gear position in P gear signals. The BMS simultaneously detects that the following three conditions are met: receiving the 0x28 service command via the CAN bus, not receiving a periodic high-voltage maintenance message from the VCU or FLZCU within a preset time threshold, and determining that the high-voltage main contactor is in the engaged state by detecting the engagement feedback signal of the high-voltage main contactor. Based on the three conditions, the logic judgment unit of the BMS does not execute the high-voltage power-down procedure triggered by the loss of VCU or FLZCU instructions, but continues to output excitation current to the drive circuit of the high-voltage main contactor to keep the high-voltage main contactor engaged. When the high voltage detection circuit of the DC-DC converter detects that the high voltage at the input terminal is greater than the preset start-up voltage threshold and the duration exceeds the preset time threshold, it starts the voltage conversion circuit to convert the high voltage to low voltage and output it to the 12V grid, forming a power supply closed loop from the high voltage battery through the high voltage main contactor to the DC-DC converter to the 12V grid to the entire vehicle ECU. After the flashing is completed, the diagnostic device sends a 0x28 00 exit quiz command and a 0x11 01 controller reset command. The VCU or FLZCU is woken up and resends the network management message and high voltage control command. When the BMS detects that the VCU or FLZCU has resumed normal communication, it stops the autonomous control logic that outputs excitation current to the drive circuit of the high-voltage main contactor and resumes the working mode of controlling the high-voltage main contactor according to the high-voltage control command sent by the VCU or FLZCU.

[0075] Through the above technical solution, this invention, in the special environment of the production line writing station, embeds dedicated power-saving logic for the production line in the BMS. When it detects entering the UDS communication silent state and simultaneously meets the triple conditions of the production line environmental signal and the high-voltage contactor engagement, the BMS no longer executes the conventional high-voltage power-down procedure triggered by the loss of VCU or FLZCU commands. Instead, it autonomously maintains the high-voltage main contactor engaged, allowing the DC-DC converter to continuously operate and supply power to the 12V grid, forming a self-sufficient power supply closed loop for the vehicle. Thus, the writing process can be completed without an external high-power power supply. After the writing process is completed, the BMS detects that the VCU or FLZCU has resumed normal communication and returns high-voltage control to the VCU or FLZCU, and the vehicle returns to normal operating mode.

[0076] Furthermore, the diagnostic equipment connection signal in the production line environment signal is obtained by detecting the physical connection status of the diagnostic interface, the vehicle stationary status signal is obtained by detecting that the vehicle speed is zero by the vehicle speed sensor, and the gear in P gear signal is obtained by detecting the gear status by the gear position sensor.

[0077] By detecting these three production line environmental signals, it is possible to accurately determine whether the vehicle is at the production line writing station, avoiding accidental triggering of the production line power protection logic under normal driving or other operating conditions, and ensuring the accuracy and safety of the function.

[0078] Furthermore, the preset time threshold is 2 to 5 times the transmission period of the periodic high-voltage maintenance message.

[0079] This time threshold setting can detect message loss in a timely manner and avoid misjudgment due to occasional communication delays, thus improving the reliability of the judgment.

[0080] Furthermore, the BMS continues to output excitation current to the drive circuit of the high-voltage main contactor by maintaining the conduction state of the drive circuit and continuously outputting current to the drive coil of the high-voltage main contactor. In this way, the BMS can bypass the control commands of the VCU or FLZCU and autonomously maintain the energized state of the high-voltage main contactor, ensuring that the high-voltage system continues to operate during communication silence periods.

[0081] Furthermore, the preset start-up voltage threshold is 80% to 95% of the rated voltage of the high-voltage battery, and the preset time threshold is 100ms to 500ms.

[0082] This threshold setting ensures that the DC-DC converter only starts working when the high voltage is stable and continuous, avoiding frequent start-stop due to voltage fluctuations and ensuring the stability of the power supply.

[0083] Furthermore, the BMS monitors the 12V mains voltage in real time, and when it detects that the 12V mains voltage is lower than a preset protection threshold, it sends an alarm signal to the diagnostic device.

[0084] By monitoring the 12V mains voltage in real time, abnormal power supply conditions can be detected in a timely manner, and alarms can be sent to diagnostic equipment, enabling production line personnel to take timely measures to avoid flashing failures or ECU damage due to low voltage.

[0085] Furthermore, while maintaining the high-voltage main contactor engaged, the BMS continuously monitors the insulation resistance of the high-voltage system. When the insulation resistance is detected to be lower than a preset safety threshold, the BMS immediately stops outputting excitation current to the drive circuit of the high-voltage main contactor and disconnects the high-voltage main contactor.

[0086] This safety protection mechanism ensures that the high voltage can be immediately disconnected when an insulation fault occurs in the high voltage system, thus preventing safety accidents and protecting the safety of personnel and equipment.

[0087] Furthermore, the BMS detects that the VCU or FLZCU has resumed normal communication as follows: continuously receiving the periodic high-voltage maintenance message sent by the VCU or FLZCU within a preset time window.

[0088] This judgment condition ensures that the VCU or FLZCU has stably restored communication, avoiding premature relinquishment of control due to misjudgment caused by occasional messages, and improving the reliability of control transfer.

[0089] Figure 2 This is a schematic flowchart illustrating the power-saving method provided in an embodiment of the present invention. Figure 2 As shown, the method includes the following steps: (a) At the production line writing station, the diagnostic equipment sends the 0x28 service command to the vehicle via the UDS protocol, so that the vehicle network enters the communication silent mode.

[0090] In this step, after the vehicle enters the production line's flashing station, production line workers or automated equipment connect the diagnostic interface of the diagnostic equipment to the vehicle's OBD interface. The diagnostic equipment establishes a communication connection with the vehicle's CAN bus through the diagnostic interface. First, it sends the 0x10 03 command to put the target ECU into an extended diagnostic session, then sends the 0x27 command for secure access authentication. After successful authentication, it sends the 0x28 01 command to put the entire vehicle network into a communication silent mode.

[0091] The complete format of the 0x28 service instruction is: 0x28<subfunction><communication type>. The subfunction byte specifies the control type: 0x00 indicates communication enabled, 0x01 indicates communication disabled, 0x02 indicates sending disabled, and 0x03 indicates receiving disabled. The communication type byte specifies the controlled communication type: 0x01 indicates regular communication messages, 0x02 indicates network management messages, and 0x03 indicates both regular communication and network management messages.

[0092] In this embodiment, the diagnostic device sends a command of 0x28 01 01, indicating that the sending and receiving of regular communication messages are disabled. This command is sent to the function address with CAN ID 0x7DF via function addressing. After receiving this command, all ECUs in the vehicle enter a communication silence mode, stop sending regular periodic messages, and only retain the diagnostic communication channel to receive and respond to diagnostic commands from the diagnostic device.

[0093] The technical advantages of silent communication mode are: By disabling the regular message transmission of unrelated ECUs, the load rate of the CAN bus is significantly reduced, message conflicts and transmission delays are avoided, and the flashing data can be transmitted to the target ECU at high speed and stably, thereby improving the flashing success rate and flashing speed.

[0094] However, the silent communication mode also brings the aforementioned technical problems: after the VCU or FLZCU enters silent mode, it stops sending high-voltage maintenance messages to the BMS. According to normal logic, the BMS will disconnect the high-voltage main contactor, causing the high-voltage system to lose power. The DC-DC converter stops working, and the 12V grid relies solely on battery power, which can easily lead to battery depletion. This invention is proposed to solve this technical problem.

[0095] (ii) The BMS detects preset production line environment signals and determines that the vehicle is in the production line writing station. The production line environment signals include diagnostic equipment connection signals, vehicle stationary status signals, and gear position in P gear signals.

[0096] In this step, the BMS determines whether the vehicle is at the production line's write-up station by detecting three production line environmental signals. The combination of these three signals is a typical characteristic of the production line write-up process, which is significantly different from normal driving or other operating conditions.

[0097] The first signal is the diagnostic device connection signal. This signal is obtained by detecting the physical connection status of the diagnostic interface. Specifically, the vehicle's OBD interface typically contains a detection pin. When the diagnostic device's interface is plugged into the OBD interface, this detection pin conducts with the corresponding pin of the diagnostic interface, forming a closed loop. The BMS determines whether the diagnostic device is connected by reading the level of this detection pin. A high level indicates that the diagnostic device is connected; a low level indicates that the diagnostic device is not connected.

[0098] The second signal is the vehicle stationary status signal. This signal is obtained by detecting a zero vehicle speed using a vehicle speed sensor. Vehicle speed sensors are typically installed on the transmission output shaft or at the wheel speed sensor location to monitor the vehicle's speed in real time. The BMS reads the data from the vehicle speed sensor via the CAN bus, and determines that the vehicle is stationary when the vehicle speed remains zero for a continuous period, such as 5 seconds.

[0099] The third signal is the gear position (P) signal. This signal is obtained by detecting the gear position using a gear position sensor. The gear position sensor is usually installed in the transmission or shift mechanism to detect the current gear in real time. The BMS reads the data from the gear position sensor via the CAN bus, and when the gear is in P (parking) position, it determines that the vehicle is in a parked state.

[0100] The BMS determines that the vehicle is at the production line writing station only when all three signals are simultaneously satisfied. This triple-judgment mechanism ensures that the production line power-saving logic is triggered only during production line writing operations, avoiding accidental triggering during normal driving or other operating conditions, thus improving the accuracy and safety of the function.

[0101] For example, during normal driving, although diagnostic equipment may be connected for real-time monitoring, the vehicle speed is not zero and the gear is not in Park (P), so the production line power preservation logic will not be triggered. Similarly, in after-sales maintenance scenarios, although diagnostic equipment is connected and the vehicle is stationary, if the gear is not in Park (P) or the vehicle is in other special states, the BMS can differentiate between production line flashing and after-sales maintenance scenarios by adding other judgment conditions, such as a maintenance mode flag, and execute different power preservation strategies.

[0102] This step uses triple environmental signal judgment to ensure that the production line power protection logic is triggered only at the production line writing station, thus improving the reliability and safety of the function.

[0103] (iii) The BMS simultaneously detects that the following three conditions are met: the 0x28 service command is received via the CAN bus, no periodic high voltage maintenance message is received from the VCU or FLZCU within a preset time threshold, and the high voltage main contactor is determined to be in the engaged state by detecting the engagement feedback signal of the high voltage main contactor.

[0104] In this step, the BMS uses a triple-condition detection mechanism to determine whether the production line power protection logic has been triggered. Figure 3 This is a flowchart of the triple condition detection process of the BMS logic judgment unit in this embodiment of the invention, combined with... Figure 3 This step will be explained in detail.

[0105] The first condition is receiving the 0x28 service command via the CAN bus. The BMS's communication silence detection module continuously monitors messages on the CAN bus. When it receives a message with CAN ID 0x7DF and data field 0x28 01 01, it identifies it as a communication silence command sent by the diagnostic device. After parsing the command, the BMS sets its internal communication silence flag to true, indicating that the vehicle network has entered communication silence mode.

[0106] The second condition is that no periodic high-voltage maintenance messages are received from the VCU or FLZCU within a preset time threshold. In normal operating mode, the VCU or FLZCU periodically sends high-voltage maintenance messages to the BMS via the CAN bus. These messages typically contain information such as the high-voltage enable flag and the target high-voltage status, with a transmission period generally between 10ms and 100ms. The BMS's message monitoring module continuously monitors the reception of these messages and records the timestamp of the most recent received message.

[0107] When the BMS receives the 0x28 service command, the VCU or FLZCU enters a communication silence state and stops sending high-voltage maintenance messages. The BMS's message monitoring module determines that a message is lost if it detects that the message has not been received within a preset time threshold. This preset time threshold is set according to the message transmission period, typically 2 to 5 times the transmission period. For example, if the message transmission period is 50ms, the preset time threshold is set to 100ms to 250ms.

[0108] The optimal time threshold setting ensures timely detection of message loss while preventing misjudgments due to occasional communication delays. If the threshold is set too low, occasional CAN bus congestion or transmission delays may lead to false alarms of message loss, triggering unnecessary power-saving logic. Conversely, if the threshold is set too high, the message loss detection time will be excessively long, potentially causing the high-voltage system to continue powering down according to normal logic for a period after message loss, failing to trigger timely power-saving logic. Therefore, setting the threshold to 2 to 5 times the message cycle is a preferred solution that balances timeliness and reliability.

[0109] The third condition is determining whether the high-voltage main contactor is in the engaged state by detecting its engagement feedback signal. The high-voltage main contactor typically contains auxiliary contacts. When the main contacts engage, the auxiliary contacts close simultaneously, forming an engagement feedback signal. The BMS's contactor status detection module determines whether the main contactor is engaged by reading the level of the auxiliary contacts. When the auxiliary contacts are high, it indicates that the main contactor is engaged; when the auxiliary contacts are low, it indicates that the main contactor is not engaged.

[0110] This condition ensures that the production line power-saving logic is triggered only when the high-voltage system is already powered on. If the high-voltage system is not powered on before entering communication silence, the main contactor is in the open state. In this case, even if message loss is detected, the power-saving logic should not be triggered because the high-voltage system itself is in a powered-off state and does not need to be maintained.

[0111] When all three conditions are met simultaneously, the BMS's logic judgment module determines that the production line's power-saving logic should be triggered. This triple-condition detection mechanism ensures that the power-saving logic is only triggered when all three conditions—communication silence, message loss, and contactor engagement—are met simultaneously, avoiding false triggering that might occur with a single-condition judgment and improving the reliability of the judgment.

[0112] Furthermore, in the above steps, the BMS records the start and end times of maintaining the high-voltage main contactor's engagement, and stores the start and end times in non-volatile memory after control is returned. By recording and storing the timing information of the power-maintenance process, a basis can be provided for subsequent fault diagnosis, data analysis, and production line optimization.

[0113] The core inventive point of this application: (1) Based on the triple triggering mechanism of UDS $28 communication silence service ($28 01 communication silence request + VCU / FLZCU periodic high voltage maintenance message loss + high voltage contactor is still in the energized state). (2) After detecting communication silence and VCU message loss, the BMS autonomously judges and bypasses VCU commands to actively maintain the production line-specific control logic for high voltage contactor engagement. (3) Production line-specific mode entry / exit mechanism deeply integrated with UDS diagnostic protocol ($28 01 entry / $28 00 exit + after controller reset, BMS returns high voltage control to VCU). (4) High-voltage control transfer mechanism between BMS and VCU.

[0114] Compared with the prior art, the present invention has the following beneficial effects: First, this invention pre-embeds dedicated power supply logic for the production line in the BMS, utilizing the vehicle's own high-voltage system to supply power to the entire vehicle during the UDS writing silent period. This eliminates the need to configure a high-power external power supply at each writing station on the production line, fundamentally eliminating the problems of high capital expenditure, complex operation and maintenance, and large workstation space occupation caused by external power supply solutions, and significantly reducing the construction and operating costs of the production line.

[0115] Secondly, this invention employs a triple-condition judgment mechanism—including production line environmental signal detection, communication silence detection, message loss detection, and contactor status detection—to ensure that the power-saving logic is triggered only at the production line writing station when specific conditions are met. This avoids accidental triggering during normal driving or other operating conditions, improving the accuracy and safety of the function. Simultaneously, by autonomously maintaining the high-voltage main contactor's engagement through the BMS and automatically detecting and starting the high-voltage converter, a self-sufficient power supply loop is formed, ensuring a stable 12V grid voltage supply during the writing process.

[0116] Third, by eliminating the need for external power connection, this invention simplifies the work process for production line workers, reduces the operation time for connecting and disconnecting power clamps, minimizes the risk of human error, and improves production cycle time. Simultaneously, it avoids writing failures caused by poor external power contact, improving production line first-pass yield and efficiency. Furthermore, by adding voltage monitoring, insulation monitoring, and time recording functions to the BMS, the safety and traceability of the power supply process are further enhanced.

[0117] Example 2 This embodiment discloses a high-voltage maintenance system for preventing power loss during the writing process in an automotive production line.

[0118] Automotive production line flashing of anti-power loss high voltage maintenance system includes: The production line environment recognition module is configured to: detect preset production line environment signals in the BMS and determine that the vehicle is in the production line writing station; The trigger condition detection module is configured to: detect three trigger conditions in the BMS, including receiving a command to enter the communication silent mode, not receiving a periodic high voltage maintenance message within a preset time threshold, and determining that the high voltage main contactor is in the energized state. The engagement control module is configured such that when all three trigger conditions are met, the BMS continues to output excitation current to the drive circuit of the high-voltage main contactor to keep the high-voltage main contactor engaged. The high-voltage maintenance module is configured as follows: the DC-DC converter converts the output voltage of the high-voltage main contactor to power the entire vehicle ECU, thereby maintaining high voltage during the production line flashing process.

[0119] It should be noted that each module in this embodiment corresponds one-to-one with each step in Embodiment 1, and their specific implementation processes are the same.

[0120] Example 3 The purpose of this embodiment is to provide a computer-readable storage medium.

[0121] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the method for maintaining high voltage to prevent power loss on an automotive production line as described in Embodiment 1 of this disclosure.

[0122] Example 4 The purpose of this embodiment is to provide an electronic device.

[0123] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the method for maintaining high voltage to prevent power loss on an automotive production line as described in Embodiment 1 of this disclosure.

[0124] The steps and methods involved in the apparatuses of Embodiments 2, 3, and 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0125] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0126] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for maintaining high voltage to prevent power loss on an automotive production line, characterized in that: Includes the following steps: BMS detects preset production line environment signals to determine if the vehicle is at the production line writing station; The BMS detects three trigger conditions, including receiving a command to enter the communication silent mode, not receiving a periodic high voltage maintenance message within a preset time threshold, and determining that the high voltage main contactor is in the energized state. Once all three triggering conditions are met, the BMS continues to output excitation current to the drive circuit of the high-voltage main contactor to keep the high-voltage main contactor engaged. The DC-DC converter converts the output voltage of the high-voltage main contactor to power the entire vehicle's ECU, thus maintaining high voltage during the production line's flashing process.

2. The method for maintaining high voltage to prevent power loss on an automotive production line as described in claim 1, characterized in that, The production line environmental signals include diagnostic equipment connection signals, vehicle stationary status signals, and gear position in P (Park) signals, wherein: The diagnostic device connection signal is obtained by detecting the physical connection status of the diagnostic interface; The vehicle stationary state signal is obtained by detecting a vehicle speed of zero using a vehicle speed sensor. The gear position signal (P gear) is obtained by detecting the gear position status through a gear position sensor.

3. The method for maintaining high voltage to prevent power loss on an automotive production line as described in claim 1, characterized in that, The preset time threshold is a set multiple of the transmission period of the periodic high-voltage maintenance message.

4. The method for maintaining high voltage to prevent power loss on an automotive production line as described in claim 1, characterized in that, The BMS continues to output excitation current to the drive circuit of the high-voltage main contactor by maintaining the conduction state of the drive circuit and continuously outputting current to the drive coil of the high-voltage main contactor.

5. The method for maintaining high voltage to prevent power loss on an automotive production line as described in claim 2, characterized in that, The DC-DC converter converts the output voltage of the high-voltage main contactor to power the entire vehicle's ECU. The specific process is as follows: When the high voltage detection circuit of the DC-DC converter detects that the high voltage at the input terminal is greater than the preset start-up voltage threshold and the duration exceeds the preset time threshold, the voltage conversion circuit is activated. The voltage conversion circuit converts high-voltage electricity into low-voltage electricity and outputs it to the 12V mains. High-voltage electricity is transmitted via the high-voltage main contactor to the DC-DC converter and the 12V power grid, reaching the entire vehicle ECU and forming a power supply closed loop. Also includes: The BMS monitors the 12V mains voltage in real time. When it detects that the 12V mains voltage is lower than a preset protection threshold, it sends an alarm signal to the diagnostic device. While maintaining the high-voltage main contactor engaged, the BMS continuously monitors the insulation resistance of the high-voltage system. When the insulation resistance is detected to be lower than a preset safety threshold, the BMS immediately stops outputting excitation current to the drive circuit of the high-voltage main contactor and disconnects the high-voltage main contactor.

6. The method for maintaining high voltage to prevent power loss on an automotive production line as described in claim 2, characterized in that, Also includes: After the flashing is completed, the diagnostic device sends an exit quiz command and a controller reset command. The VCU or FLZCU is woken up and resends the network management message and high voltage control command. When the BMS detects that the VCU or FLZCU has resumed normal communication, it stops the autonomous control logic that outputs excitation current to the drive circuit of the high-voltage main contactor and resumes the working mode of controlling the high-voltage main contactor according to the high-voltage control command sent by the VCU or FLZCU.

7. The method for maintaining high voltage to prevent power loss on an automotive production line as described in claim 6, characterized in that, The BMS detects that the VCU or FLZCU has resumed normal communication under the following condition: continuously receiving the periodic high-voltage maintenance message sent by the VCU or FLZCU within a preset time window.

8. A high-voltage maintenance system for preventing power loss during automotive production line writing, characterized in that: include: The production line environment identification module is configured to: detect preset production line environment signals in the BMS and determine that the vehicle is in the production line writing station; The trigger condition detection module is configured to: detect three trigger conditions in the BMS, including receiving a command to enter the communication silent mode, not receiving a periodic high voltage maintenance message within a preset time threshold, and determining that the high voltage main contactor is in the energized state. The engagement control module is configured such that when all three trigger conditions are met, the BMS continues to output excitation current to the drive circuit of the high-voltage main contactor to keep the high-voltage main contactor engaged. The high-voltage maintenance module is configured as follows: the DC-DC converter converts the output voltage of the high-voltage main contactor to power the entire vehicle ECU, thereby maintaining high voltage during the production line flashing process.

9. A computer-readable storage medium having a program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the method for maintaining high voltage to prevent power loss on an automotive production line as described in any one of claims 1-7.

10. An electronic device comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the method for maintaining high voltage and preventing power loss on an automotive production line as described in any one of claims 1-7.

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