An electric vehicle external discharging control system and a control method thereof

Abstract

This invention discloses a control system and method for external discharge of electric vehicles, relating to the field of electric vehicle control technology. It aims to solve the problems of poor multi-controller coordination, limited fault handling strategies, non-standardized state management, and insufficient battery protection capabilities in existing V2L control schemes. This invention constructs a hierarchical control architecture with the vehicle controller as the core control unit. It achieves closed-loop control of the entire discharge process through the vehicle controller, implements standardized timing control through a built-in V2L state machine, sets up a five-level fault classification and handling module to match differentiated fault handling strategies, dynamically adjusts discharge parameters based on the real-time battery status through the battery management system, and adds an onboard remote communication terminal for remote monitoring and data traceability. This invention significantly improves the operational stability and safety of the external discharge function, achieves an optimal balance between discharge safety and user experience, effectively protects the power battery, and possesses strong functional scalability.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle control technology, specifically to an electric vehicle external discharge control system and its control method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the application value of electric vehicle power batteries as distributed mobile energy storage units continues to stand out. Vehicle-to-Load (V2L) technology, as a core function for expanding the application scenarios of electric vehicles and enhancing their added value, has become a key research and development direction in the new energy vehicle industry. V2L technology can convert the high-voltage DC power output from the power battery into standard industrial frequency AC power through the inverter module of the on-board charger, providing stable power supply support for outdoor electrical equipment, emergency loads, etc. It is widely used in many scenarios such as outdoor camping, emergency power supply, and field operations, greatly expanding the application boundaries of electric vehicles and promoting the functional transformation of new energy vehicles from a single means of transportation to a mobile energy storage terminal.

[0003] Currently, existing V2L control solutions for electric vehicles in the industry mostly focus on the implementation of basic discharge functions, and still have many shortcomings in terms of functional safety control architecture, multi-controller collaborative control strategies, and full-process timing control mechanisms. In existing solutions, the division of control responsibilities among the vehicle controller, battery management system, and on-board charger is unclear, and there is a lack of standardized collaborative interaction mechanisms and timing control logic. Throughout the entire process of discharge function startup, operation, and termination, problems such as multi-controller command conflicts and response timing misalignments are prone to occur. This not only reduces the operational stability of the discharge function, but also easily leads to high-voltage circuit safety risks due to abnormal control timing.

[0004] Meanwhile, the safety protection mechanisms of existing V2L control schemes have significant shortcomings. On the one hand, existing schemes lack refined fault classification and handling strategies. For faults of varying severity that occur during discharge, they mostly adopt a single shutdown protection scheme, which cannot ensure the continuity of user operation while guaranteeing safety. This can easily lead to discharge interruptions due to minor faults, resulting in a poor user experience. On the other hand, existing schemes struggle to achieve dynamic closed-loop control of discharge parameters. They cannot dynamically adjust discharge voltage and current limits based on real-time state of charge, battery temperature, and individual cell voltage data of the power battery. This can easily cause irreversible damage to the power battery, such as over-discharge and over-temperature, shortening battery life.

[0005] Furthermore, existing V2L control solutions lack a standardized end-to-end state management mechanism. They fail to clearly define the state of the entire discharge process and manage the orderly state transitions, which can easily lead to problems such as abnormal state transitions and logic deadlocks, causing the discharge function to fail to start normally or terminate safely. At the same time, most solutions are not equipped with comprehensive remote monitoring and data traceability capabilities, making it impossible to achieve remote state monitoring, fault diagnosis, and full lifecycle data management of the discharge process. This is not only detrimental to remote vehicle maintenance but also fails to provide effective data support for subsequent functional optimization and upgrades.

[0006] Therefore, a control system and control method for external discharge of electric vehicles are proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a control system and method for the external discharge of an electric vehicle, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: an electric vehicle external discharge control system, comprising a central control screen, a vehicle controller, a battery management system, and an on-board charger, wherein the central control screen is communicatively connected to the vehicle controller, and the central control screen is used to receive user operation commands to enable or disable the external discharge function, and generate an external discharge switch signal based on the operation commands and send it to the vehicle controller.

[0009] The vehicle controller is communicatively connected to the battery management system and the on-board charger. The vehicle controller is used to receive external discharge switch signals, collect and comprehensively evaluate whether the vehicle status information meets the preset enabling conditions.

[0010] Specifically, an enable command is issued when the enable conditions are met; simultaneously, status monitoring, fault arbitration, and command issuance are performed throughout the entire external discharge process.

[0011] The battery management system is used to collect the battery status information of the power battery in real time after receiving the enable command from the vehicle controller, complete the handshake self-test with the on-board charger, and dynamically generate and send a discharge parameter request to the on-board charger based on the battery status information.

[0012] The on-board charger is used to detect the physical connection status of the discharge gun in real time, receive and execute the discharge parameter requests issued by the battery management system, control the internal inverter module to convert the DC power of the power battery into AC power for external output, and at the same time feed back the operating status data to the vehicle controller and the battery management system in real time.

[0013] As a further preferred embodiment of this technical solution: the vehicle controller is equipped with a V2L state machine, which includes at least a standby state, an enabled state, a discharging state, and a stopped state;

[0014] The standby state is the waiting state after the system initialization or discharge process is completed;

[0015] The enabled state is the state that the vehicle controller enters after receiving the external discharge start command and the vehicle state meets the enable conditions. It is used to wake up the battery management system and the on-board charger and wait for the two to give back the ready signal.

[0016] The state of discharge refers to the state after the on-board charger enters the normal discharge mode and outputs AC power to the outside, and is used to perform real-time monitoring of the entire discharge process.

[0017] The stopped state is the state entered after receiving a user stop command or detecting a fault triggering exit condition, and is used to execute the termination discharge process and system reset;

[0018] The vehicle controller controls the V2L state machine to perform orderly transitions between states based on the received switch signals, vehicle status information, and operating data fed back by each controller.

[0019] As a further preferred embodiment of this technical solution: the battery status information collected by the battery management system includes at least the state of charge (SOC) of the power battery, battery temperature, and individual cell voltage data. Based on the real-time changes in the battery status information, the battery management system dynamically adjusts the discharge voltage limit and discharge current limit in the discharge parameter request.

[0020] The on-board charger uses the charging connection confirmation CC signal and the charging control guidance CP signal to detect the physical connection status and reliability between the discharge gun and the vehicle in real time.

[0021] As a further preferred embodiment of this technical solution, it also includes an in-vehicle remote communication terminal, which is connected to the vehicle controller for collecting the real-time operating status, fault information and operation records of the V2L function, and reporting the above data to the cloud server to realize remote monitoring, remote diagnosis and data traceability of the external discharge function.

[0022] The vehicle controller, central control screen, battery management system, on-board charger, and on-board remote communication terminal communicate bidirectionally via on-board CAN bus or on-board Ethernet.

[0023] As a further preferred embodiment of this technical solution: the vehicle controller has a built-in fault classification and processing module, which is used to classify faults occurring during external discharge into multiple levels according to the severity of the fault and the level of impact on discharge safety, and match differentiated fault handling strategies.

[0024] Among them, Level 1 faults and Level 2 faults are minor faults and general faults, respectively. The matching handling strategy is: the system records the fault code, triggers the fault indicator light on the instrument panel, and maintains the current external discharge function without interruption.

[0025] Level 3 fault is a moderate fault, and the matching handling strategy is: the system executes a power reduction operation strategy, the battery management system regenerates and sends the reduced power limit parameters to the on-board charger, and maintains external discharge within the safety threshold.

[0026] Level 4 and Level 5 faults are respectively serious and fatal faults. The matching handling strategy is as follows: the system immediately executes the emergency shutdown procedure, the vehicle controller directly controls the high-voltage main relay to disconnect, and simultaneously sends a command to the on-board charger to stop the inverter output. At the same time, a fault alarm is issued to the user through the central control screen, and the fault information is reported to the cloud through the on-board remote communication terminal.

[0027] A control method for an electric vehicle's external discharge control system includes the following steps:

[0028] S1, User Request Stage: The central control screen receives the user's command to enable the external discharge function, generates an external discharge enable switch signal based on the command, and sends it to the vehicle controller.

[0029] S2, Enable Judgment Stage: After receiving the external discharge start switch signal, the vehicle controller collects the vehicle status information in real time and judges whether the current vehicle status meets the preset V2L function enable conditions.

[0030] If the conditions are not met, the activation request will be rejected, and the reason for not meeting the conditions will be communicated to the user through the central control screen.

[0031] If all conditions are met, proceed to the next stage;

[0032] S3, Wake-up and Enable Phase: The vehicle controller sends a wake-up command to the battery management system and on-board charger that are in a dormant state. After the wake-up is completed, it sends a V2L function enable command to the two and waits for the battery management system and on-board charger to give back a ready signal.

[0033] S4. Discharge parameter distribution stage: After the battery management system and the on-board charger complete two-way handshake communication and system self-test, the battery management system generates a discharge parameter request based on the real-time collected power battery status information and distributes it to the on-board charger.

[0034] S5. Discharge execution phase: After receiving the discharge parameter request, the on-board charger verifies that the discharge gun connection status is normal, starts the internal inverter module, closes the output relay, and converts the DC power of the power battery into standard AC power for external output according to the discharge parameter request. At the same time, it feeds back the operating status data to the vehicle controller and battery management system in real time.

[0035] S6. Discharge monitoring and exit phase: During the entire external discharge process, the vehicle controller continuously monitors the status of the vehicle's high-voltage system, the battery management system continuously monitors the status of the power battery, and the on-board charger continuously monitors the status of the output side.

[0036] When any controller detects an event that triggers the preset exit condition, it immediately reports the relevant information to the vehicle controller for arbitration. Based on the arbitration result, the vehicle controller sends a prohibition command to control each component to execute the termination discharge process. After completion, the system is reset to standby state.

[0037] As a further preferred embodiment of this technical solution: In S2, the preset V2L function enabling conditions include at least the following: the vehicle is in the parking position, the high-voltage interlock is in normal condition, the insulation resistance of the whole vehicle meets the safety threshold, the power battery has no level one or higher faults and no high-voltage system related fault codes.

[0038] In S6, the preset exit conditions include: active stop command sent by the user through the central control screen, serious power battery fault reported by the battery management system, output overload or output short circuit or abnormal discharge gun connection detected by the on-board charger, and vehicle high voltage system fault or insulation fault detected by the vehicle controller.

[0039] As a further preferred embodiment of this technical solution, it also includes a fault classification and handling step, which is executed in real time throughout the entire external discharge process, specifically as follows:

[0040] The fault information during the external discharge process is collected in real time. The fault classification and processing module of the vehicle controller classifies the fault into three levels: Level 1 minor fault, Level 2 general fault, Level 3 moderate fault, Level 4 severe fault, and Level 5 fatal fault, according to the severity of the fault and its impact on discharge safety.

[0041] For minor level 1 faults and general level 2 faults, the system records the fault code, triggers the fault indicator light on the instrument panel, and maintains the current external discharge function without interruption.

[0042] For a Level 3 moderate fault, the system executes a power reduction operation strategy. The battery management system regenerates and sends the reduced power limit parameters to the on-board charger to maintain external discharge within the safety threshold.

[0043] In response to Level 4 serious faults and Level 5 fatal faults, the system immediately executes an emergency shutdown procedure. The vehicle controller directly controls the high-voltage main relay to disconnect, and simultaneously sends a command to the on-board charger to stop the inverter output. At the same time, a fault alarm is issued to the user through the central control screen, and the fault information is reported to the cloud through the on-board remote communication terminal.

[0044] As a further preferred embodiment of this technical solution: In S6, the discharge termination process is specifically as follows:

[0045] The vehicle controller sends a discharge prohibition command to the on-board charger and the battery management system. The on-board charger stops inverter output and disconnects the output relay. The battery management system stops sending discharge parameters. After the high-voltage circuit is completely de-energized, the vehicle controller controls the V2L state machine to reset to standby state.

[0046] Compared with the prior art, the beneficial effects of the present invention are:

[0047] 1. This invention constructs a hierarchical collaborative management and control architecture to solve the problems of poor coordination among multiple controllers and lagging system response. By establishing a hierarchical management and control architecture with the vehicle controller as the core main control unit for V2L functions, and the central control screen, battery management system, and on-board charger working in coordination, the functional responsibilities, communication interfaces, and interaction sequences of each component in the entire external discharge process are clearly defined. This effectively solves the defects of existing technologies, such as the lack of coordination mechanisms between multiple controllers, control logic conflicts, and lagging system response. Furthermore, through the vehicle controller, the entire process of status monitoring, fault arbitration, and unified command issuance is realized, achieving closed-loop management of the entire discharge function from user request, startup enable, parameter issuance, discharge execution to termination and exit, significantly improving the system's response speed, coordination, and stability.

[0048] 2. This invention establishes a standardized state machine control mechanism to solve the problems of disordered state transition logic and insufficient operational reliability. By setting a standardized V2L state machine inside the vehicle controller, the entire external discharge process is divided into four core stages: standby state, enabled state, discharging state, and stopped state. The transition trigger conditions, execution actions, and exception handling logic between each state are clearly defined, achieving standardized timing control of the discharge process. The above settings ensure the orderly wake-up, handshake self-test, and readiness confirmation of each component when the function is started, and also ensure that when the user actively stops or abnormal operating conditions are triggered, the system can quickly and orderly execute the termination discharge process, avoiding functional failure or high-voltage safety risks caused by disordered state transitions, and significantly improving the reliability of system operation.

[0049] 3. This invention establishes a five-level fault classification and handling mechanism to address the problems of single fault handling strategies and insufficient safety protection capabilities. Through the fault classification and handling module built into the vehicle controller, faults during the discharge process are classified into five levels based on their severity and impact on discharge safety: Level 1: Minor Fault; Level 2: General Fault; Level 3: Moderate Fault; Level 4: Severe Fault; and Level 5: Fatal Fault. Differentiated and dedicated handling strategies are matched for each level of fault. For minor / general faults, the system maintains uninterrupted discharge function while recording fault codes and triggering user prompts, balancing functional continuity and fault traceability. For moderate faults, the system implements a power reduction operation strategy, maintaining external discharge within a safe threshold, balancing user needs and safety protection. For severe / fatal faults, the system immediately executes an emergency shutdown procedure; the vehicle controller directly controls the high-voltage main relay to disconnect, simultaneously stopping the inverter output and issuing a fault alarm, achieving the highest priority safety protection. The above mechanism greatly solves the pain points of the existing technology, such as the single fault handling strategy and the untimely response to abnormal working conditions. It achieves the optimal balance between discharge safety and user experience in all scenarios and fundamentally eliminates high voltage safety hazards.

[0050] 4. This invention achieves dynamic and refined management of power batteries, enhancing battery protection capabilities and system intelligence. Through the battery management system, it collects core state information of the power battery in real time, such as State of Charge (SOC), battery temperature, and individual cell voltage. Based on real-time changes in battery status, it dynamically adjusts the discharge voltage and discharge current limits in the discharge parameter request and simultaneously sends them to the on-board charger for execution, achieving refined and adaptive management of the power battery. This setting can fully utilize the battery's discharge capacity when the battery is in good condition to meet users' high-power electricity demands, and can also promptly limit discharge parameters when abnormal fluctuations occur in the battery status, avoiding irreversible damage to the battery caused by over-discharge, over-temperature, or abnormal individual cell voltage, effectively extending the service life of the power battery and significantly improving the system's intelligence level.

[0051] 5. This invention optimizes human-machine interaction and remote control capabilities, enhances user experience and functional scalability. Using a central control screen as the human-machine interface, it provides users with an intuitive entry point for function start / stop operations. Simultaneously, it achieves real-time visual feedback on reasons for unmet enabling conditions, operating status, and fault alarm information, improving the convenience and safety of user operation. Furthermore, by adding an in-vehicle remote communication terminal, it enables the cloud-based reporting of all data related to V2L function operating status, fault information, and user operation records. It supports remote status monitoring, remote fault diagnosis, and full lifecycle data traceability for external discharge functions. This not only provides data support for subsequent functional optimization and upgrades and fault data analysis but also provides a compatible hardware and software architecture foundation for the implementation of V2X extended functions such as V2G and V2H, exhibiting extremely strong functional scalability. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the architecture of an electric vehicle external discharge control system according to the present invention;

[0053] Figure 2 This is a flowchart illustrating the operation of a control method for an electric vehicle's external discharge control system according to the present invention.

[0054] Figure 3 This is a flowchart illustrating the V2L state machine transition process in the control method of an electric vehicle external discharge control system according to the present invention.

[0055] Figure 4 This is a flowchart illustrating the fault classification and handling process in the control method of an electric vehicle external discharge control system according to the present invention. Detailed Implementation

[0056] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0057] Example

[0058] Please see Figures 1-4 This invention provides a technical solution: an electric vehicle external discharge control system, including a central control screen (IVI), a vehicle controller (ZCU), a battery management system (BMS), and an on-board charger (OBC). The central control screen (IVI) is communicatively connected to the vehicle controller (ZCU). The central control screen (IVI) serves as a human-machine interface, receiving user operation commands to enable or disable the external discharge function, and generating an external discharge switch signal based on the operation commands to send to the vehicle controller (ZCU).

[0059] The vehicle controller (ZCU) is connected to the battery management system (BMS) and the on-board charger (OBC) respectively. As the main control unit for the vehicle's external discharge (V2L) function, the vehicle controller (ZCU) is used to receive external discharge switch signals, collect and comprehensively evaluate whether the vehicle status information (vehicle gear position, high voltage interlock, insulation resistance, etc.) meets the preset enabling conditions.

[0060] Specifically, an enable command is issued when the enable conditions are met; simultaneously, status monitoring, fault arbitration, and command issuance are performed throughout the entire external discharge process.

[0061] The battery management system (BMS) is used to collect the battery status information (state of charge, temperature, cell voltage, etc.) of the power battery in real time after receiving the enable command from the vehicle controller (ZCU). After completing the handshake self-test with the on-board charger (OBC), it dynamically generates and sends a discharge parameter request to the on-board charger (OBC) based on the battery status information.

[0062] The on-board charger (OBC) is used to detect the physical connection status of the discharge gun in real time (via CC / CP signal), receive and execute discharge parameter requests issued by the battery management system (BMS), control the internal inverter module to convert the DC power of the power battery into AC power for external output, and at the same time feed back the operating status data to the vehicle controller (ZCU) and the battery management system (BMS) in real time.

[0063] In this embodiment, specifically: the vehicle controller (ZCU) is equipped with a V2L state machine, which includes at least a standby state, an enabled state, a discharging state, and a stopped state;

[0064] Standby mode is the waiting state after the system initialization or discharge process is completed;

[0065] The enabled state is the state that the vehicle controller (ZCU) enters after receiving the external discharge start command and the vehicle state meets the enable conditions. It is used to wake up the battery management system (BMS) and the on-board charger (OBC) and wait for the two to give back the ready signal.

[0066] The discharging state is the state that the on-board charger (OBC) enters after entering normal discharging mode and outputting AC power to the outside. It is used to perform real-time monitoring of the entire external discharge process.

[0067] The stopped state is the state entered after receiving a user stop command or detecting a fault triggering exit condition. It is used to execute the termination discharge process and system reset.

[0068] The vehicle controller (ZCU) controls the V2L state machine to make orderly transitions between states based on the received switch signals, vehicle status information, and operating data fed back by each controller.

[0069] In this embodiment, specifically: the battery status information collected by the battery management system (BMS) includes at least the state of charge (SOC) of the power battery, battery temperature, and individual cell voltage data. Based on the real-time changes in the battery status information, the battery management system (BMS) dynamically adjusts the discharge voltage limit and discharge current limit in the discharge parameter request.

[0070] The on-board charger (OBC) confirms the CC signal and the charging control guidance CP signal through the charging connection, and monitors the physical connection status and reliability between the discharge gun and the vehicle in real time.

[0071] In this embodiment, specifically: it also includes an in-vehicle remote communication terminal (T-BOX), which is connected to the vehicle controller (ZCU) for collecting the real-time operating status, fault information and operation records of the V2L function, and reporting the above data to the cloud server to realize remote monitoring, remote diagnosis and data traceability of the external discharge function;

[0072] Among them, the vehicle controller (ZCU), central control screen (IVI), battery management system (BMS), on-board charger (OBC) and vehicle remote communication terminal (T-BOX) communicate bidirectionally through the vehicle CAN bus or vehicle Ethernet.

[0073] In this embodiment, specifically: the vehicle controller (ZCU) has a built-in fault classification and processing module. The fault classification and processing module is used to classify the faults that occur during the external discharge process into multiple levels according to the severity of the fault and the level of impact on discharge safety, and match differentiated fault handling strategies.

[0074] Among them, Level 1 faults and Level 2 faults are minor faults and general faults, respectively. The matching handling strategy is: the system records the fault code, triggers the fault indicator light on the instrument panel, and maintains the current external discharge function without interruption.

[0075] Level 3 fault is a moderate fault, and the matching handling strategy is: the system executes a power reduction operation strategy, the battery management system (BMS) regenerates and sends the reduced power limit parameters to the on-board charger (OBC), and maintains external discharge within the safety threshold;

[0076] Level 4 and Level 5 faults are respectively serious and fatal faults. The matching handling strategy is as follows: the system immediately executes the emergency shutdown procedure, the vehicle controller (ZCU) directly controls the high-voltage main relay to disconnect, and simultaneously sends a command to the on-board charger (OBC) to stop the inverter output. At the same time, a fault alarm is issued to the user through the central control screen (IVI), and the fault information is reported to the cloud through the vehicle remote communication terminal (T-BOX).

[0077] A control method for an electric vehicle's external discharge control system includes the following steps:

[0078] S1. User Request Stage: The central control screen (IVI) receives the user's command to enable the external discharge function, generates an external discharge enable switch signal based on the command, and sends it to the vehicle controller (ZCU).

[0079] S2, Enable Judgment Stage: After receiving the external discharge start switch signal, the vehicle controller (ZCU) collects the vehicle status information in real time and determines whether the current vehicle status meets the preset V2L function enable conditions.

[0080] If the conditions are not met, the request to enable the application will be rejected, and the reason for not meeting the conditions will be communicated to the user through the central control screen (IVI).

[0081] If all conditions are met, proceed to the next stage;

[0082] S3, Wake-up and Enable Phase: The vehicle controller (ZCU) sends a wake-up command to the battery management system (BMS) and on-board charger (OBC) which are in a dormant state. After the wake-up is completed, it sends a V2L function enable command to both of them and waits for the battery management system (BMS) and on-board charger (OBC) to give back a ready signal.

[0083] S4. Discharge parameter distribution stage: After the battery management system (BMS) and the on-board charger (OBC) complete two-way handshake communication and system self-test, the battery management system (BMS) generates discharge parameter (voltage and current limit) requests based on the real-time collected power battery status information and distributes them to the on-board charger (OBC).

[0084] S5. Discharge execution phase: After receiving the discharge parameter request, the on-board charger (OBC) verifies that the discharge gun connection status is normal, starts the internal inverter module, closes the output relay, and converts the DC power of the power battery into standard AC power for external output according to the discharge parameter request. At the same time, it feeds back the operating status data to the vehicle controller (ZCU) and battery management system (BMS) in real time.

[0085] S6. Discharge Monitoring and Exit Phase: Throughout the entire external discharge process, the vehicle controller (ZCU) continuously monitors the status of the vehicle's high-voltage system, the battery management system (BMS) continuously monitors the status of the power battery, and the on-board charger (OBC) continuously monitors the status of the output side.

[0086] When any controller detects an event that triggers the preset exit condition, it immediately reports the relevant information to the vehicle controller (ZCU) for arbitration. Based on the arbitration result, the vehicle controller (ZCU) sends a prohibition command to control each component to execute the termination discharge process. After completion, the system is reset to standby state.

[0087] In this embodiment, specifically: in S2, the preset V2L function enabling conditions include at least: the vehicle is in park, the high-voltage interlock is in normal condition, the insulation resistance of the whole vehicle meets the safety threshold, the power battery has no level one or higher faults and no high-voltage system related fault codes.

[0088] In S6, the preset exit conditions include: active stop command sent by the user through the central control screen (IVI), serious power battery fault reported by the battery management system (BMS), output overload or output short circuit or abnormal discharge gun connection detected by the on-board charger (OBC), and vehicle high voltage system fault or insulation fault detected by the vehicle controller (ZCU).

[0089] In this embodiment, specifically: it also includes a fault classification and processing step, which is executed in real time throughout the entire external discharge process, specifically as follows:

[0090] The fault information during the external discharge process is collected in real time. The fault classification and processing module of the vehicle controller (ZCU) classifies the fault into three levels: Level 1 minor fault, Level 2 general fault, Level 3 moderate fault, Level 4 severe fault, and Level 5 fatal fault, according to the severity of the fault and its impact on discharge safety.

[0091] For minor level 1 faults and general level 2 faults, the system records the fault code, triggers the fault indicator light on the instrument panel, and maintains the current external discharge function without interruption.

[0092] In response to a Level 3 moderate fault, the system implements a power reduction operation strategy. The Battery Management System (BMS) regenerates and sends the reduced power limit parameters to the On-Board Charger (OBC) to maintain external discharge within the safety threshold.

[0093] In response to Level 4 serious faults and Level 5 fatal faults, the system immediately executes an emergency shutdown procedure. The vehicle controller (ZCU) directly controls the high-voltage main relay to disconnect and simultaneously sends a command to the on-board charger (OBC) to stop the inverter output. At the same time, a fault alarm is issued to the user through the central control screen (IVI), and the fault information is reported to the cloud through the vehicle remote communication terminal (T-BOX).

[0094] In this embodiment, specifically: in S6, the discharge termination process is as follows:

[0095] The vehicle controller (ZCU) sends a discharge prohibition command to the on-board charger (OBC) and the battery management system (BMS). The on-board charger (OBC) stops the inverter output and disconnects the output relay. The battery management system (BMS) stops sending discharge parameters. After the high-voltage circuit is completely de-energized, the vehicle controller (ZCU) controls the V2L state machine to reset to standby state.

[0096] Working Principle: The electric vehicle external discharge control system of this invention uses the vehicle controller as the core main control unit for V2L (Vehicle-to-Lane) functionality. It constructs a hierarchical control architecture with multiple controllers working together. Through standardized state machine timing control, dynamic battery discharge parameter adjustment, and graded fault safety protection mechanisms, it achieves closed-loop control of the entire process of electric vehicle external discharge function from start-up, operation to termination, ensuring the safety, stability, and coordination of the discharge process. Its core working principle is as follows:

[0097] 1. Human-computer interaction and enabling access control

[0098] The central control screen serves as the system's human-machine interface, receiving user commands to enable or disable the external discharge function. Based on these commands, it generates corresponding external discharge switch signals, which are transmitted to the vehicle controller via the vehicle's CAN bus or Ethernet. Upon receiving the external discharge enable signal, the vehicle controller collects real-time vehicle status information, including gear position, high-voltage interlock status, insulation resistance, and fault codes, to verify whether the vehicle meets the preset V2L function enabling conditions. Only when all enabling conditions are met is the subsequent discharge process allowed. If not, the enable request is rejected, and the specific reasons for the failure are communicated to the user via the central control screen, thus mitigating the risk of discharge startup under unsafe conditions from the outset.

[0099] 2. Multi-component wake-up and collaborative handshake self-test

[0100] Once the vehicle status passes the enable verification, the vehicle controller sends a wake-up command to the battery management system and on-board charger, which are in a dormant state. After waking up the components, the controller sends a V2L function enable command to both. Upon receiving the enable command, the battery management system and on-board charger first complete their internal system self-tests, then perform a two-way handshake to confirm that their communication link is normal and their functions are ready. After confirming that their functions are matched and ready, they send a ready signal back to the vehicle controller, establishing a reliable foundation for component coordination for subsequent discharge execution and avoiding timing conflicts in the control of multiple components.

[0101] 3. Dynamic discharge parameter control and inverter output

[0102] After the handshake self-test is completed, the battery management system collects core status information of the power battery in real time, such as the state of charge (SOC), battery temperature, and individual cell voltage. Based on the real-time battery status, it dynamically calculates and generates discharge parameter requests such as discharge voltage limits and discharge current limits, and sends them to the on-board charger. The on-board charger first confirms the CC signal and the charging control guidance CP signal through the charging connection, and monitors the physical connection status and reliability between the discharge gun and the vehicle in real time. After confirming that the connection is normal, it receives and executes the discharge parameter requests sent by the battery management system, drives the internal inverter module to convert the high-voltage DC power output from the power battery into standard AC power, and closes the output relay to supply power externally. At the same time, the on-board charger feeds back data such as output voltage, current, and operating status to the vehicle controller and battery management system in real time, forming a dynamic closed-loop control of discharge parameters to achieve refined protection of the power battery.

[0103] 4. Full-process state control and state machine transition

[0104] The vehicle controller is equipped with a dedicated V2L state machine, which divides the entire external discharge process into four core stages: standby, enabled, discharging, and stopped. Based on received user switch signals, vehicle status information, and operational data from various controllers, the vehicle controller controls the state machine to perform orderly and unique timing transitions between these states. The standby state is the waiting state after system initialization or the end of the discharge process. Upon receiving a valid start command and meeting the vehicle's enable conditions, the state machine transitions to the enabled state, executing component wake-up and ready waiting. After receiving ready feedback from the battery management system and on-board charger, and completing the distribution of discharge parameters, it transitions to the discharging state, performing real-time monitoring of the entire discharge process. When a user-initiated stop command is received or a fault trigger exit condition is detected, it immediately transitions to the stopped state, terminating the discharge process. After the high-voltage circuit is completely de-energized and the system is reset, it returns to the standby state, achieving standardized and conflict-free control of the entire discharge process.

[0105] 5. Fault classification and handling and safety protection

[0106] Throughout the entire external discharge process, the system collects fault information from various components in real time. Through the fault classification and processing module built into the vehicle controller, faults are categorized into five levels based on their severity and impact on discharge safety, and differentiated fault handling strategies are applied accordingly. For Level 1 minor faults and Level 2 general faults, the system records fault codes and triggers the instrument panel fault indicator light, maintaining uninterrupted discharge while ensuring both continuity of use and fault traceability. For Level 3 moderate faults, the system implements a power reduction operation strategy, with the battery management system regenerating and sending reduced power limit parameters to the on-board charger, maintaining external discharge within safe thresholds to balance usage needs and safety protection. For Level 4 severe faults and Level 5 fatal faults, the system immediately executes an emergency shutdown procedure. The vehicle controller directly controls the high-voltage main relay to disconnect, simultaneously sending a command to the on-board charger to stop inverter output. At the same time, a fault alarm is issued to the user via the central control screen, achieving the highest priority safety protection and eliminating high-voltage safety risks.

[0107] 6. Remote monitoring and data traceability

[0108] The vehicle-mounted remote communication terminal communicates with the vehicle controller in real time, continuously collecting all data such as the real-time operating status of the V2L function, fault information, and user operation records, and synchronously reporting the above data to the cloud server. This enables remote status monitoring, remote fault diagnosis, and full lifecycle data traceability of the external discharge function, while also providing data support for subsequent function optimization and upgrades and fault data analysis.

[0109] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An electric vehicle external discharge control system, comprising a central control screen, a vehicle controller, a battery management system, and an on-board charger, characterized in that: The central control screen is communicatively connected to the vehicle controller. The central control screen is used to receive user operation commands to turn the external discharge function on or off, and to generate an external discharge switch signal based on the operation commands and send it to the vehicle controller. The vehicle controller is communicatively connected to the battery management system and the on-board charger. The vehicle controller is used to receive external discharge switch signals, collect and comprehensively evaluate whether the vehicle status information meets the preset enabling conditions. Specifically, an enable command is issued when the enable conditions are met; simultaneously, status monitoring, fault arbitration, and command issuance are performed throughout the entire external discharge process. The battery management system is used to collect the battery status information of the power battery in real time after receiving the enable command from the vehicle controller, complete the handshake self-test with the on-board charger, and dynamically generate and send a discharge parameter request to the on-board charger based on the battery status information. The on-board charger is used to detect the physical connection status of the discharge gun in real time, receive and execute the discharge parameter requests issued by the battery management system, control the internal inverter module to convert the DC power of the power battery into AC power for external output, and at the same time feed back the operating status data to the vehicle controller and the battery management system in real time.

2. The electric vehicle external discharge control system according to claim 1, characterized in that: The vehicle controller is equipped with a V2L state machine, which includes at least a standby state, an enabled state, a discharging state, and a stopped state. The standby state is the waiting state after the system initialization or discharge process is completed; The enabled state is the state that the vehicle controller enters after receiving the external discharge start command and the vehicle state meets the enable conditions. It is used to wake up the battery management system and the on-board charger and wait for the two to give back the ready signal. The state of discharge refers to the state after the on-board charger enters the normal discharge mode and outputs AC power to the outside, and is used to perform real-time monitoring of the entire discharge process. The stopped state is the state entered after receiving a user stop command or detecting a fault triggering exit condition, and is used to execute the termination discharge process and system reset; The vehicle controller controls the V2L state machine to perform orderly transitions between states based on the received switch signals, vehicle status information, and operating data fed back by each controller.

3. The electric vehicle external discharge control system according to claim 1, characterized in that: The battery status information collected by the battery management system includes at least the state of charge (SOC), battery temperature, and individual cell voltage data of the power battery. Based on the real-time changes in the battery status information, the battery management system dynamically adjusts the discharge voltage limit and discharge current limit in the discharge parameter request. The on-board charger uses the charging connection confirmation CC signal and the charging control guidance CP signal to detect the physical connection status and reliability between the discharge gun and the vehicle in real time.

4. The electric vehicle external discharge control system according to claim 1, characterized in that: It also includes an in-vehicle remote communication terminal, which is connected to the vehicle controller to collect the real-time operating status, fault information and operation records of the V2L function, and reports the above data to the cloud server to realize remote monitoring, remote diagnosis and data traceability of the external discharge function. The vehicle controller, central control screen, battery management system, on-board charger, and on-board remote communication terminal communicate bidirectionally via on-board CAN bus or on-board Ethernet.

5. An electric vehicle external discharge control system according to any one of claims 1-4, characterized in that: The vehicle controller has a built-in fault classification and processing module. The fault classification and processing module is used to classify faults that occur during external discharge into multiple levels according to the severity of the fault and the level of impact on discharge safety, and match them with differentiated fault handling strategies. Among them, Level 1 faults and Level 2 faults are minor faults and general faults, respectively. The matching handling strategy is: the system records the fault code, triggers the fault indicator light on the instrument panel, and maintains the current external discharge function without interruption. Level 3 fault is a moderate fault, and the matching handling strategy is: the system executes a power reduction operation strategy, the battery management system regenerates and sends the reduced power limit parameters to the on-board charger, and maintains external discharge within the safety threshold. Level 4 and Level 5 faults are respectively serious and fatal faults. The matching handling strategy is as follows: the system immediately executes the emergency shutdown procedure, the vehicle controller directly controls the high-voltage main relay to disconnect, and simultaneously sends a command to the on-board charger to stop the inverter output. At the same time, a fault alarm is issued to the user through the central control screen, and the fault information is reported to the cloud through the on-board remote communication terminal.

6. A control method for an electric vehicle's external discharge control system, characterized in that, Includes the following steps: S1, User Request Stage: The central control screen receives the user's command to enable the external discharge function, generates an external discharge enable switch signal based on the command, and sends it to the vehicle controller. S2, Enable Judgment Stage: After receiving the external discharge start switch signal, the vehicle controller collects the vehicle status information in real time and judges whether the current vehicle status meets the preset V2L function enable conditions. If the conditions are not met, the activation request will be rejected, and the reason for not meeting the conditions will be communicated to the user through the central control screen. If all conditions are met, proceed to the next stage; S3, Wake-up and Enable Phase: The vehicle controller sends a wake-up command to the battery management system and on-board charger that are in a dormant state. After the wake-up is completed, it sends a V2L function enable command to the two and waits for the battery management system and on-board charger to give back a ready signal. S4. Discharge parameter distribution stage: After the battery management system and the on-board charger complete two-way handshake communication and system self-test, the battery management system generates a discharge parameter request based on the real-time collected power battery status information and distributes it to the on-board charger. S5. Discharge execution phase: After receiving the discharge parameter request, the on-board charger verifies that the discharge gun connection status is normal, starts the internal inverter module, closes the output relay, and converts the DC power of the power battery into standard AC power for external output according to the discharge parameter request. At the same time, it feeds back the operating status data to the vehicle controller and battery management system in real time. S6. Discharge monitoring and exit phase: During the entire external discharge process, the vehicle controller continuously monitors the status of the vehicle's high-voltage system, the battery management system continuously monitors the status of the power battery, and the on-board charger continuously monitors the status of the output side. When any controller detects an event that triggers the preset exit condition, it immediately reports the relevant information to the vehicle controller for arbitration. Based on the arbitration result, the vehicle controller sends a prohibition command to control each component to execute the termination discharge process. After completion, the system is reset to standby state.

7. The control method for an electric vehicle's external discharge control system according to claim 6, characterized in that: In S2, the preset V2L function enable conditions include at least: the vehicle is in park, the high voltage interlock is in normal condition, the vehicle insulation resistance meets the safety threshold, the power battery has no level 1 or higher faults, and there are no high voltage system related fault codes. In S6, the preset exit conditions include: active stop command sent by the user through the central control screen, serious power battery fault reported by the battery management system, output overload or output short circuit or abnormal discharge gun connection detected by the on-board charger, and vehicle high voltage system fault or insulation fault detected by the vehicle controller.

8. The control method for an electric vehicle's external discharge control system according to claim 6, characterized in that: It also includes a fault classification and handling step, which is executed in real time throughout the entire external discharge process, specifically as follows: The fault information during the external discharge process is collected in real time. The fault classification and processing module of the vehicle controller classifies the fault into three levels: Level 1 minor fault, Level 2 general fault, Level 3 moderate fault, Level 4 severe fault, and Level 5 fatal fault, according to the severity of the fault and its impact on discharge safety. For minor level 1 faults and general level 2 faults, the system records the fault code, triggers the fault indicator light on the instrument panel, and maintains the current external discharge function without interruption. For a Level 3 moderate fault, the system executes a power reduction operation strategy. The battery management system regenerates and sends the reduced power limit parameters to the on-board charger to maintain external discharge within the safety threshold. In response to Level 4 serious faults and Level 5 fatal faults, the system immediately executes an emergency shutdown procedure. The vehicle controller directly controls the high-voltage main relay to disconnect, and simultaneously sends a command to the on-board charger to stop the inverter output. At the same time, a fault alarm is issued to the user through the central control screen, and the fault information is reported to the cloud through the on-board remote communication terminal.

9. The control method for an electric vehicle's external discharge control system according to claim 6, characterized in that: In S6, the discharge termination procedure is as follows: The vehicle controller sends a discharge prohibition command to the on-board charger and the battery management system. The on-board charger stops inverter output and disconnects the output relay. The battery management system stops sending discharge parameters. After the high-voltage circuit is completely de-energized, the vehicle controller controls the V2L state machine to reset to standby state.

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