Vehicle-to-vehicle charge-discharge control method, battery management system, and discharging device

Abstract

The application discloses a vehicle-to-vehicle charging and discharging control method, a battery management system and a discharging device, and relates to the field of automobile charging. The method comprises the following steps: receiving an identification signal sent by a conversion device, the identification signal being used to represent the number of high-voltage branches supported by a currently connected charging gun; determining the number of high-voltage branches participating in vehicle-to-vehicle charging and discharging according to the identification signal; and performing a charging and discharging task, which comprises the following steps: generating corresponding control instructions based on the number of high-voltage branches, and sending the control instructions to the conversion device, so as to control the conversion device to perform charging and discharging operations between a discharging vehicle and a charging vehicle; wherein the conversion device is used to convert first electric energy of the discharging vehicle into second electric energy of the charging vehicle. According to the application, the number of high-voltage branches participating in charging and discharging is automatically identified and matched at the vehicle end, single / multi-branch plug-and-play branch control is realized, different branch configurations are compatible, the discharging capacity and efficiency are improved, and the system complexity and cost are reduced.

Description

Technical Field

[0001] This application relates to the field of automotive charging technology, and in particular to a vehicle-to-vehicle charging and discharging control method, a battery management system, and a discharging device. Background Technology

[0002] Existing vehicle charging and discharging systems mostly employ a single-gun, single-branch topology, lacking the ability to automatically identify and adapt to the actual number of available high-voltage branches at the conversion device end. This makes it difficult to achieve plug-and-play parallel discharge of multiple branches under different branch configurations, and cannot meet the high current and high efficiency requirements of multi-circuit parallel systems. Furthermore, the division of labor between the vehicle-side BMS and the conversion device is unclear, with branch identification, control decision-making, and execution functions being cross-coupled, resulting in complex system implementation and high costs.

[0003] The information disclosed in this background section is included only to enhance the understanding of the context of this disclosure, and therefore may contain information that does not constitute relevant technology currently known to those skilled in the art. Summary of the Invention

[0004] This application provides a vehicle-to-vehicle charging and discharging control method to solve the problem in the prior art that it is difficult to adaptively configure according to the number of high-voltage branches supported by the charging gun, resulting in low charging and discharging efficiency.

[0005] The technical solution adopted in this application is as follows: In a first aspect, this application provides a vehicle-to-vehicle charging and discharging control method, which is applied to the battery management system of a discharging vehicle, and the method includes: Receive an identification signal sent by the conversion device to characterize the number of high-voltage branches supported by the currently connected charging gun; The number of high-voltage branches involved in vehicle charging and discharging is determined based on the identification signals. Performing charging and discharging tasks includes: generating corresponding control commands based on the number of high-voltage branches, and sending the control commands to the conversion device to control the conversion device to perform charging and discharging operations between the discharging vehicle and the charging vehicle; The conversion device is used to convert the first electrical energy of the discharging vehicle into the second electrical energy of the charging vehicle.

[0006] This application introduces an adaptive control mechanism for the number of high-voltage branches based on identification signals into the battery management system of a discharging vehicle. This mechanism enables the discharging vehicle to automatically identify and match charging guns with different high-voltage branch configurations. Based on the identification results, the number of high-voltage branches participating in charging and discharging is dynamically determined, and the control strategy is adjusted accordingly. This improves the energy transfer efficiency and system compatibility of the vehicle during the charging and discharging process, and reduces the safety risks and hardware costs caused by branch configuration mismatch.

[0007] In conjunction with the first aspect, in one optional implementation, the identification signal is a voltage value generated by the identification circuit inside the charging gun. The number of high-voltage branches participating in the vehicle-to-vehicle charging and discharging process is determined based on the identification signal, including: The number of high-voltage branches is determined based on the voltage value and the preset voltage range.

[0008] This application automatically determines the number of high-voltage branches involved in vehicle-to-vehicle charging and discharging by matching the voltage value generated by the internal identification circuit of the charging gun with a preset voltage range. This enables adaptive configuration of the charging gun's support capability for the discharging vehicle, improving charging and discharging efficiency without significantly increasing hardware complexity, and enhancing system compatibility and electrical safety.

[0009] In conjunction with the first aspect, in one optional implementation, the preset voltage range includes a first voltage range and a second voltage range; The number of high-voltage branches is determined based on the voltage value and the preset voltage range, including: When the voltage value is within the first voltage range, the number of high-voltage branches is determined to be a single branch; When the voltage value is within the second voltage range, the number of high-voltage branches is determined to be two branches; There is no overlap between the first voltage range and the second voltage range.

[0010] This application adopts a first voltage range and a second voltage range that do not overlap with each other, corresponding to single-branch and dual-branch working modes respectively. This enables the discharging vehicle to clearly distinguish and accurately determine the number of high-voltage branches participating in the vehicle's charging and discharging based on the identified voltage value, avoiding ambiguity in voltage determination and improving the reliability of branch configuration and the stability of the charging and discharging process.

[0011] In conjunction with the first aspect, in one optional implementation, the identification signal is a resistance value generated by the identification circuit inside the charging gun. The number of high-voltage branches participating in vehicle-to-vehicle charging and discharging is determined based on the identification signal, including: The number of high-voltage branches is determined based on the resistance value and the preset resistance range.

[0012] This application uses the resistance value generated by the internal identification circuit of the charging gun and matches it with a preset resistance range to automatically determine the number of high-voltage branches involved in vehicle charging and discharging. This enables adaptive configuration of the charging gun's support capability for the discharging vehicle, improving charging and discharging efficiency without significantly increasing hardware complexity, and enhancing system compatibility and electrical safety.

[0013] In conjunction with the first aspect, in one optional implementation, the preset resistance range includes a first resistance range and a second resistance range; The number of high-voltage branches is determined based on the resistance value and the preset resistance range, including: When the resistance value is within the first resistance range, the number of high-voltage branches is determined to be a single branch; When the resistance value is within the second resistance range, the number of high-voltage branches is determined to be two branches; There is no overlap between the first resistance range and the second resistance range.

[0014] This application divides the resistance values ​​generated by the internal identification circuit of the charging gun into a first resistance range and a second resistance range that do not overlap with each other, and corresponds to the number of single-branch and dual-branch high-voltage branches respectively. This achieves clear distinction and automatic determination of the number of high-voltage branches, avoids the risk of misjudgment caused by overlapping resistance ranges, improves the reliability and stability of branch identification, helps to achieve precise control of the vehicle charging and discharging process and improves system safety.

[0015] In conjunction with the first aspect, in one alternative implementation, the method further includes: Send request messages for vehicle identification and connection security detection to the conversion device via the charging communication bus; The receiving conversion device responds to the response message returned by the request message, and obtains the identity information of the currently connected vehicle and the detection results used to characterize the connection security based on the response message; Vehicle identification is performed based on the identity information of the currently connected vehicle, and connection security is confirmed based on the detection results; After completing vehicle identification and connection security verification, an auxiliary power supply command is sent to the conversion device to wake up and / or supply power to the battery management system of the charging vehicle through the auxiliary power in the conversion device.

[0016] This application utilizes a charging communication bus to interact with the conversion device during the vehicle-to-vehicle charging and discharging process. It requests and obtains response messages containing information on the number of high-voltage branches, vehicle identity information, and connection security detection results. Only after completing vehicle identification and connection security confirmation is a command issued to wake up and / or provide auxiliary power to the charging vehicle's battery management system. This pre-verification of vehicle identity and connection security before waking up the battery management system and providing auxiliary power effectively avoids risks associated with abnormal vehicle access and insecure connections. It ensures the safety and reliability of the battery management system wake-up and auxiliary power supply process, and improves the overall safety and reliability of the vehicle-to-vehicle charging and discharging system.

[0017] In conjunction with the first aspect, in one alternative implementation, the method further includes: After the auxiliary power supply wakes up and / or supplies power to the battery management system of the charging vehicle, the electronic lock status of the charging gun connected to the discharging vehicle and the discharge circuit switch status are obtained through the conversion device, and the corresponding charging and discharging tasks and / or fault handling tasks are executed according to the electronic lock status and the discharge circuit switch status.

[0018] This application, by waking up and / or supplying power to the battery management system of the charging vehicle via auxiliary power, further acquires the electronic lock status of the charging gun connected to the discharging vehicle and the switch status of the discharge circuit, and executes corresponding charging and discharging tasks and / or fault handling tasks accordingly. This achieves real-time monitoring and linkage control of charging and discharging execution conditions and fault status, and can promptly interrupt or adjust the charging and discharging process when an anomaly is detected, thereby improving the safety and reliability of the vehicle's charging and discharging process and avoiding safety hazards caused by abnormal unlocking of the electronic lock or mis-connection of the discharge circuit.

[0019] In conjunction with the first aspect, in one alternative implementation, the method further includes: performing a charge / discharge task after the fault handling task is completed.

[0020] This application imposes sequential constraints on fault handling and charging / discharging control by executing charging / discharging tasks only after the relevant faults have been eliminated or properly handled. This ensures that vehicle-to-vehicle charging / discharging operations are only permitted after the relevant faults have been eliminated or properly handled, thereby avoiding the accidental initiation of the charging / discharging process while the fault has not been resolved. This improves the safety and stability of the system operation and reduces the risk of equipment damage and personal safety.

[0021] In conjunction with the first aspect, in one alternative implementation, the method further includes: Before performing the charging and discharging task, the maximum output current is determined based on the first maximum current of the discharging vehicle and the second maximum current of the conversion device; The minimum output current is determined based on the first minimum current of the discharge vehicle and the second minimum current of the conversion device; The maximum and minimum output currents are used to limit the range of output current during charging and discharging operations.

[0022] This application achieves precise current constraint control over the vehicle-to-vehicle charging and discharging process by collaboratively determining the maximum and minimum output currents based on the maximum and minimum current values ​​of the discharging vehicle and the conversion device before performing the charging and discharging task. This effectively avoids device overload and safety hazards caused by excessive output current, or low charging and discharging efficiency and resource waste caused by insufficient output current, thereby improving the overall safety, reliability and charging and discharging efficiency of the system.

[0023] In conjunction with the first aspect, in one alternative implementation, the method further includes: The maximum output current is determined based on the first maximum current of the discharge vehicle and the second maximum current of the conversion device, including: taking the smaller of the first maximum current and the second maximum current as the maximum output current; And / or, determine the minimum output current based on the first minimum current of the discharge vehicle and the second minimum current of the conversion device, including: taking the larger of the first minimum current and the second minimum current as the minimum output current.

[0024] This application achieves adaptive matching of the output current range by taking the smaller of the maximum allowable current values ​​of the discharging vehicle and the conversion device when determining the maximum output current, and taking the larger of the minimum allowable current values ​​of the two when determining the minimum output current. This ensures that the upper and lower limits of the output current simultaneously meet the safety operating requirements of both the discharging vehicle and the conversion device. Under the premise of ensuring that the rated capacity of either side is not exceeded, it helps to avoid the risk of overcurrent or undercurrent abnormality caused by insufficient capacity of one side, and improves the electrical matching and operational safety of the vehicle to the vehicle charging and discharging process.

[0025] In conjunction with the first aspect, in one alternative implementation, the method further includes: During the charging and discharging process, the current and voltage measurements from each branch of the charging vehicle are received and forwarded by the conversion device. Based on the difference between the measured current value of each branch and the preset current value, a current adjustment command is sent to the conversion device to adjust the output current of each branch. Based on the difference between the measured voltage value of each branch and the preset voltage value, a voltage adjustment command is sent to the conversion device to adjust the output voltage of each branch.

[0026] This application achieves closed-loop regulation and control of the output current and voltage of each branch of the charging vehicle in real time during the execution of the charging and discharging task. It acquires the measured current and voltage values ​​of each branch of the charging vehicle forwarded by the conversion device in real time, and compares them with the preset current and voltage values ​​respectively. Based on the difference, it sends the corresponding current adjustment command and voltage adjustment command to the conversion device. This enables each branch to dynamically track the target set value, improves the consistency and stability of the output of multiple branches, and helps to maintain an efficient and stable charging and discharging process under different operating conditions, reducing the impact of single branch abnormalities on the overall system.

[0027] In conjunction with the first aspect, in one alternative implementation, the method further includes: During the charging and discharging process, the insulation resistance value of the high-voltage circuit to ground is detected by the insulation detection circuit in the receiving conversion device. When the insulation resistance of the high-voltage circuit to ground does not reach the preset safety threshold, a stop command is sent to the conversion device to control the conversion device to stop outputting electrical energy to the charging vehicle.

[0028] This application achieves online monitoring and linkage protection control of the high-voltage circuit insulation status by acquiring the insulation resistance value of the high-voltage circuit to ground detected by the insulation detection circuit in the conversion device in real time during the charging and discharging task, and promptly issuing a stop command to the conversion device to stop the output of electrical energy to the charging vehicle when the insulation resistance value does not reach the preset safety threshold. This enables the output to be quickly cut off in the early stage of insulation degradation or fault, avoiding safety hazards such as leakage, electric shock or equipment damage caused by poor insulation, thereby significantly improving the electrical safety of the charging and discharging process and the reliability of system operation.

[0029] Secondly, this application provides a battery management system for performing the methods in the first aspect or any optional implementation thereof.

[0030] Thirdly, this application provides a discharge device, which includes a power battery pack and the battery management system described in the second aspect above.

[0031] The beneficial effects of the second and third aspects described above can be referred to in the first aspect or any of the optional implementations of the first aspect, and will not be elaborated here. Based on the implementations provided in the above aspects, this application can also be further combined to provide more implementations.

[0032] Other advantages, objectives and features of this application will be partly apparent from the description below, and partly understood by those skilled in the art through study and practice of this application. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 This is one of the flowcharts of the vehicle-to-vehicle charging and discharging control method provided in the embodiments of this application; Figure 2 This is the second flowchart of the vehicle-to-vehicle charging and discharging control method provided in the embodiments of this application; Figure 3 This is the third flowchart of the vehicle-to-vehicle charging and discharging control method provided in the embodiments of this application; Figure 4This is the fourth flowchart of the vehicle-to-vehicle charging and discharging control method provided in the embodiments of this application; Figure 5 This is the fifth flowchart of the vehicle-to-vehicle charging and discharging control method provided in the embodiments of this application; Figure 6 This is the sixth flowchart of the vehicle-to-vehicle charging and discharging control method provided in the embodiments of this application; Figure 7 This is the seventh flowchart of the vehicle-to-vehicle charging and discharging control method provided in the embodiments of this application. Detailed Implementation

[0035] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0036] The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items. In this application, "at least one" means one or more, and "more than one" means two or more. The terms "first," "second," and other ordinal terms used in this application may be used to describe various constituent elements, but these constituent elements are not limited by these terms. The purpose of using these terms is solely to distinguish one constituent element from others and should not be construed as indicating or implying relative importance. For example, without departing from the scope of this application, a first constituent element may be named a second constituent element, and similarly, a second constituent element may be named a first constituent element.

[0037] Before introducing the embodiments of this application, the background technology involved in this application will be introduced first.

[0038] Existing vehicle-to-vehicle charging and discharging solutions mostly employ a single-interface, single-channel topology, lacking an automatic detection and matching mechanism for the actual number of available high-voltage channels (high-voltage branches) on the conversion device side. This makes it difficult to achieve plug-and-play parallel discharge of multiple channels under different channel configurations, thus failing to meet the requirements of multi-loop parallel systems for high current output and high-efficiency operation. Furthermore, the functional boundaries between the vehicle battery management system and the conversion device are not clearly defined, with overlapping functions such as channel identification, control decision-making, and execution, resulting in a complex system architecture, high implementation difficulty, and high overall cost.

[0039] In summary, the vehicle charging and discharging solutions in the relevant technologies suffer from insufficient adaptive capability of channel configuration, complex system architecture, and high cost.

[0040] To address the aforementioned problems, embodiments of this application provide a vehicle-to-vehicle charging and discharging control method. (Reference) Figure 1 , Figure 1 This is one of the flowcharts for a vehicle-to-vehicle charging and discharging control method provided in an embodiment of this application.

[0041] like Figure 1 As shown, the vehicle charging and discharging control method is applied to the battery management system of a discharging vehicle, and the method includes at least the following steps: S101: Receive an identification signal sent by the conversion device to characterize the number of high-voltage branches supported by the currently connected charging gun; S103: Determine the number of high-voltage branches involved in vehicle charging and discharging based on the identification signal; S105: Perform charging and discharging tasks, including: generating corresponding control commands based on the number of high-voltage branches, and sending the control commands to the conversion device to control the conversion device to perform charging and discharging operations between the discharging vehicle and the charging vehicle.

[0042] The conversion device proposed in this application sets two parallel input channels in the interface connected to the vehicle providing electrical energy (i.e., the discharging vehicle) and two parallel output channels in the interface connected to the vehicle receiving electrical energy (i.e., the charging vehicle). All four channels are connected to the same DC-DC conversion unit (such as a DC / DC converter) and a unified control system (such as a microcontroller unit, MCU) to achieve a dual-channel (i.e., dual-branch) parallel current boosting scheme. Specifically, on the side providing electrical energy, the DC power from the battery of the discharging vehicle is distributed to the two parallel input channels, allowing current to be input simultaneously through both channels. On the side receiving electrical energy, two parallel output channels are correspondingly set, one-to-one with the aforementioned two input channels, to simultaneously deliver the processed DC power to the battery of the charging vehicle. The electrical energy from all channels is first collected in the same power conversion unit (the DC / DC converter in the conversion device), which uniformly boosts or bucks the input DC power before sending it out in parallel through the two output channels.

[0043] This vehicle-to-vehicle (V2V) charging and discharging control method effectively manages energy exchange between electric vehicles through the battery management system (BMS) of the discharging vehicle. First, the BMS receives an identification signal from the conversion device (S101), which indicates the number of high-voltage branches supported by the currently connected charging gun. High-voltage branches are parallel channels for energy transmission, and their number determines the amount of energy that can be transmitted simultaneously. Receiving the identification signal is crucial because understanding the number of branches helps optimize energy transmission efficiency and ensure connection security. Next, the number of high-voltage branches participating in charging and discharging is determined based on the identification signal (S103). Once the number of branches is determined, the system generates corresponding control commands (S105) to guide the conversion device on how to perform energy conversion between the two vehicles. The conversion device converts the first electrical energy from the discharging vehicle into a second electrical energy suitable for the charging vehicle to meet the latter's battery charging needs. By sending control commands, the system ensures the safety and efficiency of the energy transmission process.

[0044] For example, in an emergency, an electric vehicle might need assistance due to low battery, and another electric vehicle can provide power support. For instance, a fully charged electric vehicle can charge a depleted vehicle using a multi-branch charging gun. Once the battery management system identifies the number of high-voltage branches supported by the charging gun, it instructs the conversion device to transfer power in the most efficient way. This not only prevents vehicles from breaking down due to depleted battery but also enables rapid rescue without relying on external power, improving the flexibility and emergency response capabilities of electric vehicles.

[0045] In some embodiments, reference Figure 2 , Figure 2 This is a second flowchart of a vehicle-to-vehicle charging and discharging control method provided in an embodiment of this application. Figure 2 As shown, the identification signal is generated by the identification circuit inside the charging gun, specifically manifested as a voltage value (a low-voltage signal). By detecting this voltage value and combining it with a preset voltage range, the number of high-voltage branches participating in vehicle-to-vehicle (V2V) charging and discharging can be determined (step S201). The principle of this process is that the identification circuit inside the charging gun generates a specific voltage value to characterize the number of branches it supports, based on standards set during its design or manufacturing. The BMS of the discharging vehicle can determine how many high-voltage branches the charging gun can support by analyzing this voltage value, and optimize the path and method of power transmission accordingly. This not only helps to improve the efficiency of energy transmission, but also ensures the safety and reliability of the charging process during energy exchange between different vehicles.

[0046] For example, one voltage value might indicate support for only a single high-voltage branch, in which case electrical energy is transmitted through a single channel, suitable for standard charging needs. Another voltage value might indicate support for dual-branch transmission, where electrical energy is transmitted in parallel through two high-voltage branches to meet higher charging power requirements. In this way, the system can automatically adjust the charging strategy between single-branch and dual-branch modes based on the actual capacity of the charging gun, ensuring optimal efficiency and safety during vehicle-to-vehicle charging.

[0047] In some embodiments, the system determines the number of high-voltage branches supported by the charging gun by using preset voltage ranges. These voltage ranges include a first voltage range and a second voltage range, and these two ranges do not overlap. Specifically, when the voltage value detected by the battery management system falls within the first voltage range, the BMS of the discharging vehicle determines that the charging gun only supports high-voltage transmission of a single branch (step S203). This means that electrical energy will be transmitted on a single high-voltage channel, thereby achieving basic energy exchange. When the voltage value falls within the second voltage range, the BMS of the discharging vehicle determines that the charging gun supports dual-branch transmission, meaning that electrical energy can be transmitted through two parallel high-voltage branches (step S205). This multi-branch transmission method can improve the efficiency and speed of energy transmission and is suitable for scenarios requiring fast charging or high-power transmission.

[0048] For example, suppose the first voltage range is set to 5 to 7 volts, and the second voltage range is set to 11 to 13 volts. When an electric vehicle is connected to the charging gun, if the system detects a voltage of 6 volts, which falls within the first voltage range, the system determines that the charging gun only supports single-path transmission. Conversely, if the detected voltage is 12 volts, it falls within the second voltage range, and the system determines that it supports dual-path transmission. This design ensures that the system adjusts the energy transmission strategy according to the actual capacity supported by the charging gun, thereby optimizing the charging process and improving safety.

[0049] In some embodiments, reference Figure 3 , Figure 3 This is the third flowchart of a vehicle-to-vehicle charging and discharging control method provided in an embodiment of this application. Figure 3 As shown, the charging gun contains an identification circuit that indicates the number of high-voltage branches it supports by generating a specific resistance value. By measuring this resistance value and comparing it with a preset resistance range, the number of high-voltage branches that can be used for vehicle-to-vehicle (V2V) charging and discharging can be determined (step S301). Different resistance values ​​correspond to different numbers of branches.

[0050] For example, one resistance value might indicate support for only a single high-voltage branch, in which case electrical energy is transmitted through a single channel, suitable for standard charging needs. Another resistance value might indicate support for multiple branches, such as dual or more, suitable for situations requiring faster charging speeds or higher power transmission. In this way, the system can automatically adjust its charging strategy based on the actual capabilities of the charging gun, ensuring optimal efficiency and safety during charging between vehicles.

[0051] In some embodiments, a specific resistance value can be generated by the identification circuit inside the charging gun to indicate the number of high-voltage branches it supports. To achieve this, two non-overlapping resistance ranges are preset: a first resistance range and a second resistance range. Based on the relationship between the resistance value and these preset ranges, the BMS of the discharging vehicle can determine the number of high-voltage branches involved in vehicle-to-vehicle (V2V) charging and discharging. When the identification resistance value of the charging gun falls within the first resistance range, it can be determined that the charging gun only supports single-branch transmission (step S303); this means that electrical energy is transmitted through a single high-voltage channel, suitable for standard charging requirements. When the resistance value is within the second resistance range, it is determined that dual-branch transmission is supported (step S305), suitable for scenarios requiring higher power and faster charging. This clear distinction ensures that the system can automatically adjust the charging strategy according to the actual resistance value, optimizing the efficiency and safety of the charging process.

[0052] For example, suppose the system defines a first resistance range of 900 ohms to 1100 ohms, and a second resistance range of 2000 ohms to 3000 ohms, with no overlap between them. When the resistance value generated by the charging gun's identification circuit is detected to be 930 ohms, it can be determined that the charging gun only supports single-branch transmission, with electrical energy transmitted through a single high-voltage channel, meeting general charging needs. On the other hand, if the detected resistance value is 2200 ohms, it is determined that dual-branch transmission is supported, a setting suitable for scenarios requiring higher charging speeds. This method allows for flexible and accurate adjustment of the charging mode according to actual needs, ensuring both efficiency and safety during the charging process.

[0053] In some embodiments, reference Figure 4 , Figure 4 This is the fourth flowchart of a vehicle-to-vehicle charging and discharging control method provided in an embodiment of this application. Figure 4As shown, the vehicle-to-vehicle charging and discharging control method further includes the discharging vehicle's BMS sending a request message to the conversion device via the charging communication bus (step S401) to perform vehicle identification and connection security detection. After receiving the response message returned by the conversion device in response to the request message, the discharging vehicle's BMS can obtain the identity information of the currently connected vehicle and the detection results used to characterize the connection security (step S403). Based on this information, the discharging vehicle's BMS can perform vehicle identification and confirm the connection security according to the detection results (step S405). After ensuring vehicle identity and connection security, the discharging vehicle's BMS sends an auxiliary power supply command to the conversion device to wake up and / or supply power to the charging vehicle's battery management system through the auxiliary power supply in the conversion device (step S407). In this way, it is ensured that during the charging process, not only can the correct vehicle be identified, but also the connection security and the reliability of the power supply are guaranteed.

[0054] For example, the BMS of the discharging vehicle sends a request message to the converter via the charging communication bus, requesting detailed information about the current charging environment. Upon receiving the request, the converter returns a response message containing the connected vehicle's identity information and the results of the connection security check. Assume the system learns from the response message that the connected vehicle's identity information matches expectations and the security check results indicate a stable connection. After confirming this information is correct, the system sends an auxiliary power supply command to wake up and / or power the vehicle's battery management system using the auxiliary power supply in the converter, ensuring the vehicle can operate normally and maintain communication during charging. This process not only improves the efficiency of the charging process but also enhances the safety of the charging operation.

[0055] In some embodiments, after the auxiliary power supply wakes up and / or supplies power to the battery management system of the charging vehicle, the BMS of the discharging vehicle obtains the electronic lock status and discharge circuit switch status of the charging gun connected to the discharging vehicle through a conversion device. This status information helps the BMS determine the current connection and operating status of the system. Based on the electronic lock status, the BMS can confirm whether the charging gun is correctly locked, thereby ensuring the security of the physical connection, while the discharge circuit switch status helps the BMS determine whether current can be safely transmitted between vehicles. Based on this status information, the BMS can perform corresponding charging and discharging tasks (step S409), such as starting or stopping the charging process, or performing fault handling tasks when an abnormal condition is detected, to ensure the safety and effectiveness of the entire process.

[0056] For example, after the auxiliary power is started, the BMS of the discharging vehicle checks the status of the electronic lock and the discharge circuit switch via a conversion device. Assuming the BMS detects that the electronic lock is correctly locked and the discharge circuit switch is closed, this indicates that the system is ready to safely begin the charging and discharging process. After confirming that these conditions are met, the BMS initiates the discharge task, transferring power to the battery system of another vehicle. If at any point in the process the BMS detects that the electronic lock is not locked or the discharge circuit switch is abnormal (e.g., the switch is not closed), it will immediately stop the charging process and perform fault handling tasks, such as issuing an alarm or locking the system to prevent potential safety hazards. This method ensures the safety and reliability of vehicle-to-vehicle charging and discharging.

[0057] In some embodiments, in the event of a fault, the BMS first identifies and handles the fault. This may involve re-checking the electronic lock status, discharge circuit switch status, or other system parameters to diagnose and correct the problem. Once the fault handling task is completed and the system returns to a safe and stable state, the BMS reassesses the current connectivity. If all conditions meet the charging and discharging requirements, the BMS will continue or restart the charging and discharging task (step S411). In this way, the BMS ensures that the charging and discharging process can proceed safely after any abnormal situation has been properly handled.

[0058] For example, during charging, the BMS of the discharging vehicle detects that the discharge circuit switch is not properly closed, causing charging to be interrupted. The BMS immediately initiates a fault handling task, identifying the problem by checking the connection status and performing system diagnostics. After fault handling, the BMS confirms that the fault has been resolved and the discharge circuit switch status has returned to normal. Next, the BMS reassesses the electronic lock status of the charging gun and other necessary conditions. When all conditions are met, the BMS restarts the discharge process, transferring electrical energy to another vehicle. This method not only ensures timely fault handling but also maximizes the efficiency of charging and discharging tasks while ensuring safety.

[0059] In some embodiments, reference Figure 5 , Figure 5 This is the fifth flowchart of a vehicle-to-vehicle charging and discharging control method provided in an embodiment of this application. Figure 5As shown, during the vehicle-to-vehicle charging and discharging control process, the BMS of the discharging vehicle determines the output current range before executing the charging and discharging task (steps S501-S503). Specifically, the BMS first determines the maximum output current of the system based on the first maximum current of the discharging vehicle and the second maximum current of the conversion device (step S501). This process ensures that the system will not exceed its current limit during charging and discharging, thereby avoiding damage to the battery or conversion device. Simultaneously, the BMS also determines the minimum output current based on the first minimum current of the discharging vehicle and the second minimum current of the conversion device (step S503). This minimum value ensures that the system operates at the lowest current within a safe range. Through these steps, the maximum and minimum output currents together define the output current range of the charging and discharging operation, ensuring that the entire process is carried out under safe and efficient conditions.

[0060] In some embodiments, during vehicle-to-vehicle charging and discharging control, the BMS of the discharging vehicle determines the output current range of the charging and discharging process by comparing current values. When determining the maximum output current, the BMS compares a first maximum current value of the discharging vehicle with a second maximum current value of the conversion device, and takes the smaller of the two as the maximum output current. This strategy ensures that the system does not damage the conversion device or the battery due to excessive current. Similarly, when determining the minimum output current, the BMS compares a first minimum current value of the discharging vehicle with a second minimum current value of the conversion device, and takes the larger of the two as the minimum output current. This ensures that the necessary current level is maintained at all times throughout the charging and discharging process for efficient and stable energy transfer.

[0061] It is worth noting that, for application scenarios using the GB / T 27930-2015 DC charging communication protocol, the discharge vehicle's BMS can map the determined maximum and minimum output currents to the values ​​of the SPN2826 and SPN2827 fields in the CML message, respectively. SPN2826 represents the maximum allowable output current, and SPN2827 represents the minimum allowable output current. This allows the output current range, determined by the collaborative constraints between the discharge vehicle and the conversion device, to be synchronously communicated to the charging-side control node without altering the message structure. Furthermore, this solution can also employ protocols such as GB / T27930-2023.

[0062] For dual-branch operating mode, when the conversion devices corresponding to each branch have different rated output capabilities, the discharge vehicle BMS can also summarize the maximum / minimum allowable output current of the two branches, and use the smaller of the maximum allowable current of the two branches as the reported value of SPN2826, and the larger of the minimum allowable current of the two branches as the reported value of SPN2827, so as to ensure that the overall output current range meets the safety operating requirements of both branches at the same time.

[0063] For example, in a specific charge / discharge operation, the BMS of the discharging vehicle detects that its maximum current handling capacity is 120 amps, while the connected converter's maximum current handling capacity is 100 amps. Therefore, the BMS sets its maximum output current to 100 amps to prevent exceeding the converter's capacity and protect it from overload. When determining the minimum output current, the BMS finds its minimum operating current is 15 amps, while the converter's minimum operating current requirement is 20 amps. Therefore, the BMS sets its minimum output current to 20 amps to ensure the converter can operate normally. This means that the current during the charge / discharge process will be limited between 20 and 100 amps to ensure that all system components operate within their safe operating range throughout the entire operation. This method not only ensures system safety but also optimizes the efficiency of the charge / discharge process.

[0064] In some embodiments, reference Figure 6 , Figure 6 This is the sixth flowchart of a vehicle-to-vehicle charging and discharging control method provided in an embodiment of this application. Figure 6 As shown, when the discharge vehicle's BMS performs charging and discharging tasks, it dynamically adjusts the current and voltage of each branch (steps S601-S605) to ensure the efficiency and stability of energy transfer. Specifically, the BMS receives the measured current and voltage values ​​of each branch from the charging vehicle, forwarded by the conversion device (step S601). By comparing these measured values ​​with preset current and voltage values, the BMS can identify the difference between the actual and target values. Based on this difference, the BMS issues a current adjustment command to the conversion device to correct the output current of each branch, ensuring that the current is at the optimal level (step S603). Similarly, the BMS also issues a voltage adjustment command based on voltage differences to optimize the output voltage of each branch (step S605). This method ensures the high efficiency and safety of the entire charging and discharging process through continuous monitoring and dynamic adjustment.

[0065] It is worth noting that for vehicle-to-vehicle charging and discharging scenarios supporting dual branches, the battery management system (BMS2) of the charging vehicle can extend the BCL message format of the GB / T 27930-2015 protocol when sending charging requests to the discharging side. In the PGN4096 BCL message, in addition to the current demand field for the first branch, a new SPN4073 field is added to characterize the charging current request for the second branch. The physical quantity of this field is the current demand (A), and its value represents the expected charging current magnitude for the second branch. After receiving and parsing the BCL message, the discharging vehicle's BMS1 allocates and coordinates the output current of the two branches based on the current demand of the first branch and the current demand of the second branch represented by SPN4073, combined with the aforementioned maximum / minimum output current constraints.

[0066] To enable the discharge vehicle's BMS to distinguish the real-time charging status of different branches, the charging vehicle's BMS2 can add a second branch measurement field to the existing first branch voltage and current measurement fields when sending the BCS message from PGN4352. For example, SPN4075 can be added to represent the charging voltage measurement value (V) of the second branch, and SPN4076 can be added to represent the charging current measurement value (A) of the second branch. During the charging and discharging process, the charging vehicle's BMS2 periodically fills the voltage and current values ​​sampled from the second branch into SPN4075 and SPN4076, and forwards them to the discharge vehicle's BMS1 through a conversion device. This facilitates closed-loop regulation and safety monitoring of different branches on the discharge side.

[0067] For example, in a specific charge / discharge operation, the BMS of the discharging vehicle receives a current measurement of 48 amps from a branch forwarded by the converter, while the preset target current is 50 amps. Upon detecting the discrepancy, the BMS sends a current adjustment command to the converter to increase the output current of that branch to reach the target value. Similarly, assuming the voltage measurement of that branch is 695 volts, while the preset voltage is 700 volts, the BMS will issue a voltage adjustment command, requesting the converter to increase the output voltage of that branch. These adjustments ensure that each branch operates under the expected current and voltage conditions, thereby maximizing charge / discharge efficiency and minimizing energy loss.

[0068] It is worth noting that, to facilitate the charging vehicle's acquisition of the output status of each branch of the discharging vehicle, the discharging vehicle's BMS1 can extend the status information by referring to the CCS message in the GB / T 27930-2015 protocol. In the CCS message of PGN4608, in addition to the voltage and current fields used to indicate the overall output status, dedicated measurement fields for the second branch are further added. For example, SPN4081 is added to indicate the output voltage measurement value (V) of the second branch, and SPN4082 is added to indicate the charging current measurement value (A) of the second branch.

[0069] It should be noted that the output voltage and current measurements of the second branch in the aforementioned CCS message are not directly collected by the discharge vehicle's BMS1. Instead, they are measured in real time by the DC / DC converter corresponding to the second branch or by the sampling module within the converter, and then reported to BMS1 via the vehicle communication network. BMS1 then fills these real-time sampled values ​​into the SPN4081 and SPN4082 fields and sends them to the charging vehicle's BMS2 along with the CCS message. This method ensures that the reported measurement points are consistent with the actual locations of the power devices, improving the accuracy and timeliness of multi-branch output status monitoring.

[0070] In some embodiments, the BMS of the discharging vehicle monitors the insulation resistance of the high-voltage circuit to ground (steps S607-S609) during charging and discharging operations to ensure system safety. Specifically, the BMS receives measurement results from the insulation detection circuit of the conversion device, which provides information on the insulation resistance of the high-voltage circuit relative to ground. If the detected insulation resistance is lower than a preset safety threshold, this indicates a potential leakage or other safety hazard. To prevent possible safety accidents, the BMS immediately issues a stop command to the conversion device, controlling it to stop outputting electrical energy to the charging vehicle. This mechanism ensures the safety of the charging and discharging process through real-time monitoring and rapid response.

[0071] For example, in a specific operational scenario, the BMS of the discharge vehicle receives a measurement from the insulation detection circuit showing that the high-voltage circuit's insulation resistance to ground is 300 ohms / volt, while the preset safety threshold is 600 ohms / volt. Because the measured resistance is below the safety threshold, the BMS determines there is a safety risk and immediately issues a stop command to the conversion device, requiring it to cease power output. This measure effectively prevents potential electric shock risks or equipment damage, ensuring the safe operation of the system.

[0072] refer to Figure 7 , Figure 7 This is flowchart seven of the vehicle-to-vehicle charging and discharging control methods provided in the embodiments of this application. Figure 7 As shown, in the scenario of dual-gun connection where there are both discharging and charging vehicles, the battery management system BMS1 of the discharging vehicle and the battery management system BMS2 of the charging vehicle establish physical connections with the DC / DC converter through their respective charging guns. They also complete a series of processes such as wake-up, identification, version negotiation and control message exchange through the CAN bus to achieve orderly start-up and safe control of the vehicle's charging and discharging process.

[0073] Specifically, when gun 1 is inserted into the interface on the discharge vehicle side, BMS1 detects specific resistance / voltage signals through its internal identification circuit, or is activated by the wake-up signal output from the DC / DC converter at the A1+ / A1− terminals, thereby completing the detection of gun 1's insertion status and power-on wake-up of the discharge vehicle side. A1+ / A1− are the positive / negative auxiliary power terminals corresponding to gun 1, used to provide wake-up and low-voltage power supply signals to the BMS side after the discharge vehicle inserts the gun, establishing initial power supply and communication between the discharge vehicle's BMS1 and the converter. Subsequently, BMS1 sends a specific frame message to the DC / DC converter via the CAN bus, requesting identification of the converter and confirmation of the discharge vehicle's gun insertion status. After completing internal identification, the DC / DC converter returns the identification result via CAN communication, confirming successful identification on the discharge vehicle side.

[0074] On the charging vehicle side, when charging gun 2 is inserted into the charging vehicle interface, BMS2 can also be woken up by detecting a preset special resistance / voltage characteristic value through its internal identification circuit, or by powering on and activating through a wake-up signal output by the DC / DC converter at the auxiliary power terminal (such as A2+ / A2−) corresponding to charging gun 2. At this time, the charging vehicle BMS2 receives the discharge vehicle identification status forwarded by the DC / DC converter via the CAN bus, and confirms that the charging vehicle has successfully plugged in the charging gun based on the detected charging gun resistance characteristic. After detecting that both the discharge vehicle and the charging vehicle have plugged in and completed the initial identification, the converter sends corresponding status messages to BMS1 and BMS2 via the CAN bus, indicating: the DC / DC converter has successfully identified the vehicle, the discharge vehicle has successfully plugged in the charging gun, and the charging vehicle has successfully plugged in the charging gun.

[0075] After completing the basic identification and wake-up process, the discharging vehicle BMS1 and the charging vehicle BMS2 negotiate versions via CAN communication: BMS1 first sends a version negotiation message, and BMS2, upon receiving the message via the CAN bus, returns its own version negotiation response message. After multiple rounds of interaction, both sides confirm that the protocol versions are consistent and record the negotiation results. Simultaneously, the DC / DC converter can send, receive, or monitor relevant CAN messages to ensure software version and communication protocol compatibility at each node of the system. When BMS1 and BMS2 receive the version negotiation message from the other end and confirm "version negotiation successful," the converter and BMS1 exchange specific identification frames to complete the final confirmation of the charging vehicle's identity, achieving "charging vehicle identification successful."

[0076] Based on this, the system enters the charging process: on the one hand, the conversion device sends a charging message to BMS2 via the CAN bus, informing it of the current available power, current, voltage, and status information; on the other hand, the discharging vehicle BMS1, based on the aforementioned identification results, version negotiation results, and high-voltage branch configuration, issues control commands to the DC / DC conversion device, controlling the conversion device to perform energy transfer between the discharging vehicle and the charging vehicle according to a predetermined strategy. Simultaneously, the conversion device periodically sends detection information to the discharging vehicle BMS1 via CAN communication, including insulation status, branch current, voltage, and gun insertion detection results for guns 1 and 2, enabling the discharging vehicle BMS to perform closed-loop monitoring and protection control throughout the charging and discharging process. Through the wake-up mechanism based on auxiliary power terminals such as A1+ / A1−, and the CAN communication and specific frame message interaction between multiple nodes, this embodiment of the application can achieve collaborative identification and safety control between the discharging vehicle, the charging vehicle, and the DC / DC conversion device in a dual-branch, multi-node environment, thereby ensuring reliable startup and stable operation of the vehicle's charging and discharging process.

[0077] It is worth noting that, in the aforementioned charging process, the BMS1 of the discharging vehicle and the BMS2 of the charging vehicle have adapted and extended the handshake, parameter negotiation, and control messages for vehicle-to-vehicle charging and discharging, referencing the GB / T27930-2015 DC charging communication protocol, to support different high-voltage branch configuration scenarios such as single-branch and dual-branch configurations. After completing version negotiation and entering the charging message interaction stage, the BMS1 of the discharging vehicle can also identify dual-branch capability by referring to the CRM / BRM messages in the GB / T 27930-2015 protocol. Specifically, BMS1, acting as the discharge-side control node, sends a CRM message to PGN256, filling the SPN2560 field with the value 0x11 to indicate that the discharging vehicle supports dual-branch operation mode. When the charging vehicle BMS2 receives the BRM message from PGN512 and parses it to find SPN2560=0x11, if it also supports dual-branch operation, it sets the SPN2574 field to 0x11 in its returned message to indicate that the charging vehicle also supports dual-branch operation. Once both parties declare support for dual-branch operation, BMS1 sends another CRM message, setting the SPN2560 field to 0xBB to indicate successful dual-branch recognition. Upon receiving SPN2560=0xBB, BMS2 confirms the dual-branch recognition is complete and subsequently performs vehicle-to-vehicle charging and discharging control according to the dual-branch configuration.

[0078] Based on the same technical concept, embodiments of this application also provide a battery management system for performing the methods in any of the above embodiments.

[0079] Based on the same technical concept, this application also provides a discharge device, which includes a power battery pack and the aforementioned battery management system.

[0080] The above description involves various modules and units. It should be noted that the division of these modules and units in the description is for clarity. However, in actual implementation, the boundaries between various modules and units may be blurred. For example, any or all functional modules and units in this application may share various hardware and / or software elements. As another example, any and / or all functional modules in this application may be wholly or partially implemented by a shared processor executing software instructions. Furthermore, various software sub-modules executed by one or more processors may be shared among various software modules. Accordingly, unless expressly required, the scope of this application is not limited by mandatory boundaries between various hardware and / or software elements.

[0081] It should be noted that the order of description of the embodiments in this application is not intended to limit the priority of the embodiments.

[0082] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application and in its specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0083] It should be noted that, unless otherwise specified, the term "connected" or "linked" in this application includes not only directly connecting two entities, but also indirectly connecting them through other entities that have beneficial improvement effects.

[0084] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many forms under the guidance of this application without departing from the spirit and scope of protection of the claims. All equivalent transformations made based on the technical concept of this application and the content of the description and drawings of this application, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of this application.

Claims

1. A vehicle-to-vehicle charging and discharging control method, characterized in that, The method is applied to the battery management system of a discharging vehicle, and the method includes: Receive an identification signal sent by the conversion device to characterize the number of high-voltage branches supported by the currently connected charging gun; The number of high-voltage branches involved in vehicle charging and discharging is determined based on the identification signal. Performing a charging and discharging task includes: generating a corresponding control command based on the number of high-voltage branches, and sending the control command to the conversion device to control the conversion device to perform charging and discharging operations between the discharging vehicle and the charging vehicle; The conversion device is used to convert the first electrical energy of the discharging vehicle into the second electrical energy of the charging vehicle. The method further includes: The charging communication bus sends a request message to the conversion device for vehicle identification and connection security detection. The system receives a response message returned by the conversion device in response to the request message, and obtains the identity information of the currently connected vehicle and the detection results used to characterize the connection security based on the response message. Vehicle identification is performed based on the identity information of the currently connected vehicle, and connection security is confirmed based on the detection results; After completing the vehicle identification and connection security confirmation, an auxiliary power supply command is sent to the conversion device to wake up and / or supply power to the battery management system of the charging vehicle through the auxiliary power in the conversion device. After the auxiliary power source wakes up and / or supplies power to the battery management system of the charging vehicle, the conversion device obtains the electronic lock status and discharge circuit switch status of the charging gun connected to the discharging vehicle, and executes the corresponding charging / discharging task and / or fault handling task according to the electronic lock status and the discharge circuit switch status.

2. The method according to claim 1, characterized in that, The identification signal is a voltage value generated by the internal identification circuit of the charging gun. Determining the number of high-voltage branches participating in vehicle charging and discharging based on the identification signal includes: The number of high-voltage branches is determined based on the voltage value and the preset voltage range.

3. The method according to claim 2, characterized in that, The preset voltage range includes a first voltage range and a second voltage range; The step of determining the number of high-voltage branches based on the voltage value and a preset voltage range includes: When the voltage value is within the first voltage range, the number of high-voltage branches is determined to be a single branch; When the voltage value is within the second voltage range, the number of high-voltage branches is determined to be two branches; There is no overlap between the first voltage range and the second voltage range.

4. The method according to claim 1, characterized in that, The identification signal is a resistance value generated by the internal identification circuit of the charging gun. Determining the number of high-voltage branches participating in vehicle charging and discharging based on the identification signal includes: The number of high-voltage branches is determined based on the resistance value and the preset resistance range.

5. The method according to claim 4, characterized in that, The preset resistance range includes a first resistance range and a second resistance range; The step of determining the number of high-voltage branches based on the resistance value and a preset resistance range includes: When the resistance value is within the first resistance value range, the number of high-voltage branches is determined to be a single branch; When the resistance value is within the second resistance value range, the number of high-voltage branches is determined to be two branches; There is no overlap between the first resistance range and the second resistance range.

6. The method according to claim 1, characterized in that, The method further includes: executing the charging and discharging task after the fault handling task is completed.

7. The method according to any one of claims 1-6, characterized in that, The method further includes: Before performing the charging and discharging task, the maximum output current is determined based on the first maximum current of the discharging vehicle and the second maximum current of the conversion device; The minimum output current is determined based on the first minimum current of the discharge vehicle and the second minimum current of the conversion device; The maximum output current and the minimum output current are used to limit the output current range of the charging and discharging operation.

8. The method according to claim 7, characterized in that, The method further includes: The step of determining the maximum output current based on the first maximum current of the discharge vehicle and the second maximum current of the conversion device includes: taking the smaller of the first maximum current and the second maximum current as the maximum output current; And / or, determining the minimum output current based on the first minimum current of the discharge vehicle and the second minimum current of the conversion device includes: taking the larger of the first minimum current and the second minimum current as the minimum output current.

9. The method according to claim 1, characterized in that, The method further includes: During the execution of the charging and discharging task, the current measurement value and voltage measurement value from each branch of the charging vehicle are received and forwarded by the conversion device. Based on the difference between the measured current value of each branch and the preset current value, a current adjustment command is sent to the conversion device to adjust the output current of each branch. Based on the difference between the measured voltage value of each branch and the preset voltage value, a voltage adjustment command is issued to the conversion device to adjust the output voltage of each branch.

10. The method according to claim 1, characterized in that, The method further includes: During the charging and discharging process, the insulation resistance value of the high-voltage circuit to ground detected by the insulation detection circuit in the conversion device is received; When the insulation resistance of the high-voltage circuit to ground does not reach the preset safety threshold, a stop command is sent to the conversion device to control the conversion device to stop outputting electrical energy to the charging vehicle.

11. A battery management system, characterized in that, The battery management system is used to perform the method as described in any one of claims 1-10.

12. A discharge device, characterized in that, Includes the battery management system and power battery pack as described in claim 11.

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