An electric vehicle fast charging thermal management control method and system

Abstract

The application discloses a kind of electric vehicle fast charging thermal management control method and system, it is related to electric vehicle charging technical field, it solves the problem that prior art does not establish complete fast charging thermal management state machine control process, high voltage switch action timing is not standard, battery swap scene adaptability is poor.This application is based on state machine logic to realize control, contain eight continuous operating states, strictly define the action timing of each stage high voltage switch, according to battery temperature determination result in turn into pure temperature control, side temperature control side charging and pure charging state, while setting battery swap scene special processing step, hierarchical power heating control mode and dynamic current control logic.The application can realize the smooth connection of each stage of fast charging thermal management, avoid high voltage circuit misoperation, improve the safety and stability of fast charging process, optimize charging efficiency, prolong the service life of battery, applicable to the DC fast charging thermal management system of various electric vehicles.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle charging technology, specifically to a method and system for thermal management control of fast charging of electric vehicles. Background Technology

[0002] With the rapid development of the electric vehicle industry, DC fast charging technology has become a core technology for improving the user experience of electric vehicles. As the main power source for electric vehicles, the charging and discharging performance, cycle life, and operational safety of lithium-ion batteries are significantly correlated with operating temperature. In low or high temperature environments, batteries cannot reach their optimal fast charging state. Therefore, efficient and safe fast charging thermal management control technology is a crucial element in ensuring the fast charging performance of electric vehicles.

[0003] Currently, existing electric vehicle fast-charging thermal management controls generally employ a fixed temperature threshold triggering method. When the battery temperature exceeds the preset fast-charging temperature range, the heating or cooling system is activated to regulate the temperature. This type of control has relatively simple logic and lacks a complete state machine control flow. There is a lack of smooth connection mechanisms between the pre-charging, heating / cooling, and charging stages. The timing of the four high-voltage switches for positive, negative, pre-charging, and fast charging is not strictly standardized. In actual operation, faults such as pre-charging failure, high-voltage surges, and contactor sticking are prone to occur. Furthermore, existing technologies do not have a specific thermal management quick exit mechanism for battery swapping scenarios, and the collision fault diagnosis and high-voltage interlock detection logic cannot effectively coordinate with the battery swapping process. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and system for thermal management control of fast charging of electric vehicles. This addresses the problems of the prior art not establishing a standardized state machine control process that includes the entire process of pre-charging, temperature control and charging, and not strictly defining the timing of high-voltage switch actions for each stage. This results in inconsistent control logic, unclear state transitions, and easy malfunctions of the high-voltage circuit during fast charging, which in turn affects the efficiency of fast charging of electric vehicles and the safety of the system.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In one aspect, a method for controlling the thermal management of fast charging of electric vehicles, comprising the following steps: Step 1: Perform initialization. The battery management system completes the initialization of the entire battery system and performs self-tests on switches, sensors, and communication modules. All high-voltage switches remain open. Step 2: After the self-test passes, it enters the standby state, waits for the vehicle controller to give instructions and determine the battery temperature. If the self-test fails, it will directly enter the power-down state. Step 3: When the preset conditions are met, start the pre-charge operation and control the corresponding high-voltage switch to close to complete the high-voltage circuit pre-charge; Step 4: After pre-charging is completed, the system enters a transition state, adjusting the high-voltage switch status to prepare for the temperature control and charging phase. Step 5: Based on the battery temperature determination result, enter pure temperature control state, simultaneous temperature control and charging state, or pure charging state respectively; when entering pure temperature control state, control the battery heating or cooling system to regulate the battery temperature. Step 6: Once the battery temperature reaches the first preset threshold under pure temperature control, it enters a state of simultaneous temperature control and charging, where temperature adjustment and charging operations are performed at the same time. Step 7: Once the battery temperature reaches the second preset threshold while the battery is under temperature control and charging conditions, it enters pure charging mode and performs full-power fast charging. Step 8: When charging is complete or a fault is detected, enter the power-off state, disconnect all high-voltage switches and record the operating data.

[0006] Furthermore, the pure temperature control state includes a pure heating state. In this state, a graded power heating control method is used. The pure temperature control state features three levels of full-power heating (suitable for low temperatures and large temperature differences) and two levels of power heating (suitable for medium-temperature conditions). The heating power level is primarily determined based on the current battery temperature, while simultaneously adjusting the charging current using dynamic current control logic. This dynamic current control logic is implemented using the following formula: ,in, This indicates a requested charging current, in amperes. This indicates the initial charging current, in amperes. This represents the current adjustment rate coefficient, with a value of 1 ampere per second; This indicates the maximum permissible charging current, measured in amperes. This indicates the current actual charging current of the busbar, in amperes. When the busbar charging current is greater than or equal to 5 amperes, the charging current is requested to decrease according to the current adjustment rate coefficient. When the busbar charging current is less than 1 ampere, the charging current is requested to increase according to the current adjustment rate coefficient until the charging current stabilizes within the preset range.

[0007] Furthermore, it also includes special handling steps for battery swapping scenarios. When the battery heating controller receives a message from the vehicle controller indicating that the mode switching status level is greater than or equal to the ready state, it performs the following operations within a preset time: unconditionally set the thermal management request to a no-demand state, maintain the thermal management no-demand state throughout the battery swapping process, suspend the collision fault diagnosis operation, and suspend the high-voltage interlock signal detection operation. The collision fault diagnosis operation includes hard-wired collision signal detection and controller area network collision signal detection.

[0008] Furthermore, the pure temperature control state includes a pure heating state and a pure cooling state. Both the pure heating state and the pure cooling state are equipped with an overtime protection mechanism. When the continuous running time of the pure heating state or the pure cooling state reaches the preset duration, the current pure temperature control state will be automatically exited and the state will be powered off or jump to other corresponding states according to the current battery status.

[0009] Furthermore, the preset conditions for initiating the pre-charging operation in step three include: the vehicle controller sends a charging permission command, the battery heating controller has no serious charging fault, the vehicle is only plugged into a DC charging gun, the battery heating controller completes fast charging interaction with the charging pile and sends a corresponding interaction signal, the battery temperature determination result indicates that temperature adjustment is required, and the high-voltage switch status during the pre-charging operation is: negative switch closed, pre-charging switch closed, positive switch open, and fast charging switch open.

[0010] Furthermore, in step four, the high-voltage switch states in the transition state are: positive switch closed, negative switch closed, pre-charge switch open, and fast-charge switch open. The transition state is used to complete the high-voltage circuit state switching from the pre-charge stage to the pure temperature control stage, avoiding the impact of sudden changes in the high-voltage circuit state on the battery and electrical components, and ensuring the stable operation of the high-voltage circuit in the subsequent temperature control stage.

[0011] Furthermore, in step five, the high-voltage switch state in the pure temperature control state is that the negative switch is closed, the fast charging switch is closed, the positive switch is open, and the pre-charge switch is open. In the pure temperature control state, only the battery temperature regulation system is running and no charging operation is performed. The battery temperature determination in step five is based on the initial lowest battery temperature. The determination result corresponds to entering the deep low temperature heating (pure heating), medium low temperature heating (heating while charging), or pure charging state. Different states correspond to different heating power levels and control logic.

[0012] Furthermore, in step six, the high-voltage switch states during the simultaneous temperature control and charging process are: positive switch closed, negative switch closed, pre-charge switch open, and fast-charge switch closed. During this process, the temperature regulation system and the charging system operate simultaneously, adjusting the temperature regulation power and charging current in real time according to changes in battery temperature, and gradually increasing the charging power while ensuring that the battery temperature remains within a safe range.

[0013] Furthermore, the pure temperature control state includes a pure cooling state, and the pure cooling process is logically consistent with the heating process: after the battery management system is woken up, it completes an initialization self-test. After the self-test passes, it enters a standby state. After the pre-charging conditions are met, the pre-charging operation is started. After the pre-charging is completed, it enters a transition state. Depending on the battery temperature determination result, it enters a pure cooling state, a cooling-while-charging state, or a pure charging state. When the battery temperature meets the pure cooling conditions, it enters a pure cooling state. After pure cooling is completed and the voltage conditions are met, it enters a cooling-while-charging state. After the battery temperature reaches the standard, it enters a pure charging state.

[0014] On the other hand, a fast-charging thermal management control system for electric vehicles, applicable to a fast-charging thermal management control method for electric vehicles, includes a battery heating controller, a vehicle controller, a high-voltage switch group, a temperature regulation system, and a charging interaction module. The battery heating controller is communicatively connected to the vehicle controller, the high-voltage switch group, the temperature regulation system, and the charging interaction module. The high-voltage switch group includes a positive switch, a negative switch, a pre-charge switch, and a fast-charge switch. The battery heating controller controls the timing of the high-voltage switch group and the operating status of the temperature regulation system according to the vehicle controller's instructions, the charging gun status, the battery temperature, the battery voltage, and the fault status.

[0015] Compared with existing technologies, this method and system for controlling the thermal management of fast charging of electric vehicles has the following advantages: I. This invention establishes a standardized state machine control process encompassing initialization, standby, pre-charging, transition, pure temperature control, simultaneous temperature control and charging, pure charging, and power-off stages. It strictly defines the action sequence of the four high-voltage switches (positive, negative, pre-charging, and fast charging) for each stage, enabling seamless connection and clear state transitions in the control logic of each stage of fast charging thermal management. This effectively avoids faults such as pre-charging failure, high-voltage surges, and contactor sticking caused by sudden changes in the high-voltage circuit state, thereby significantly improving the system safety and operational stability of the DC fast charging process for electric vehicles and ensuring the smooth execution of the fast charging process.

[0016] Second, this invention designs a graded power heating control method and dynamic current control logic for different battery temperature conditions, and sets up a rapid exit mechanism for thermal management in battery swapping scenarios and an overtime protection mechanism for pure temperature control. This enables precise adjustment of battery temperature, avoids battery damage caused by low-temperature high-current charging, adapts to the special usage requirements of electric vehicles in battery swapping mode, prevents abnormal overtime operation in the temperature control process, thereby effectively extending battery cycle life and improving the environmental adaptability and multi-scenario compatibility of the thermal management system.

[0017] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0019] Figure 1 This is a flowchart of the fast charging heating control process of the present invention; Figure 2 This is a flowchart of the fast charging and cooling control process of the present invention; Figure 3 This is a flowchart of an embodiment of the fast charging heating control of the present invention. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0021] As attached Figure 1-3 As shown, an electric vehicle fast-charging thermal management control system includes a battery heating controller, a vehicle controller, a high-voltage switch group, a temperature regulation system, and a charging interaction module. The battery heating controller is communicatively connected to the vehicle controller, the high-voltage switch group, the temperature regulation system, and the charging interaction module. The high-voltage switch group includes a positive switch, a negative switch, a pre-charge switch, and a fast-charge switch. The battery heating controller controls the timing of the high-voltage switch group and the operating status of the temperature regulation system based on vehicle controller commands, charging gun status, battery temperature, battery voltage, and fault status.

[0022] The temperature control system includes a heating unit and a cooling unit. The heating unit uses a positive temperature coefficient heater or a heat pump system. The cooling unit uses a cooling circuit consisting of an electric compressor and a heat exchanger. The charging interaction module is used to realize the communication interaction between the battery heating controller and the DC charging pile, and to complete the charging process as required by national standards, such as charging handshake and voltage and current negotiation.

[0023] This invention also discloses a fast-charging thermal management control method for electric vehicles, implemented based on state machine logic. State transitions are determined by a comprehensive assessment of vehicle controller instructions, charging gun status, temperature conditions, voltage conditions, and fault conditions. The timing of the actions of the four high-voltage switches (positive, negative, pre-charge, and fast-charge) is strictly defined. The state machine comprises eight states: initialization, standby, pre-charge, transition, pure temperature control, simultaneous temperature control and charging, pure charging, and power-off.

[0024] Step 1: Initialization. After the vehicle is plugged into the DC charging gun, the charging gun's wake-up signal triggers the battery management system (BMS) to power on and start. The BMS first completes the initialization of the entire battery system. This initialization includes self-tests of internal switching devices, temperature sensors, voltage sensors, current sensors, and the communication module. During the self-test, all high-voltage switches remain open: the positive switch, negative switch, pre-charge switch, and fast-charge switch are all open.

[0025] The self-test includes checking whether the output signals of each sensor are within the normal range, whether the communication module can send and receive data normally, and whether each high-voltage switch can perform opening and closing actions normally. If any serious fault is found during the self-test, the battery heating controller will immediately enter the power-off state. If all self-tests pass, the battery heating controller will enter the standby state.

[0026] Step two, standby mode. In standby mode, the battery heating controller continuously waits for commands from the vehicle controller. Simultaneously, it collects real-time temperature data from the battery pack and determines the temperature. The temperature determination is based on the minimum and maximum temperatures calculated from the temperature values ​​collected by multiple temperature sensors within the battery pack.

[0027] The battery heating controller continuously monitors the charging gun's connection and fault status in standby mode. If a charging gun disconnection or a new serious fault is detected, the battery heating controller immediately goes into power-down mode. If the pre-charge start conditions are met, the battery heating controller enters pre-charge mode.

[0028] Step 3, pre-charging operation. The pre-charging operation requires five conditions to be met simultaneously. First, the vehicle controller sends a charging permission command. Second, the battery heating controller has no serious charging faults. Third, only the DC charging gun is plugged into the vehicle; no AC slow charging gun is plugged in. Fourth, the battery heating controller completes fast charging interaction with the charging station and sends the corresponding interaction signal. Fifth, the battery temperature determination result indicates that temperature adjustment is needed.

[0029] During pre-charging, the battery heating controller controls the high-voltage switch group to operate according to a preset timing sequence. First, the negative switch closes, then the pre-charging switch closes. The positive switch and fast-charging switch remain open. During pre-charging, the battery heating controller continuously monitors the voltage changes in the pre-charging circuit. When the pre-charging voltage reaches a preset threshold, pre-charging is considered complete. After pre-charging is complete, the battery heating controller enters a transition state. If a fault occurs during pre-charging or pre-charging timeout, the battery heating controller directly enters a power-off state.

[0030] Step four, the transition state, is used to complete the high-voltage circuit state switch from the pre-charge stage to the pure temperature control stage. This avoids sudden changes in the high-voltage circuit state from impacting the battery and electrical components. It also ensures stable operation of the high-voltage circuit during the subsequent temperature control stage.

[0031] After pre-charging is complete, the battery heating controller controls the high-voltage switch group to adjust its state. First, the positive switch is closed, then the pre-charging switch is opened. The negative switch remains closed. The fast-charging switch remains open. After the transition state lasts for a preset time, the battery heating controller, based on the battery's initial temperature determination, directly switches to a pure temperature control state, a state of simultaneous temperature control and charging, or a pure charging state.

[0032] Step 5: Pure Temperature Control Mode. Pure temperature control mode includes pure heating mode and pure cooling mode. In pure temperature control mode, only the battery temperature regulation system operates and no charging operation is performed. The high-voltage switch status in pure temperature control mode is: negative switch closed, fast charge switch closed, positive switch open, and pre-charge switch open.

[0033] Both pure heating and pure cooling modes have a timeout protection mechanism. When the continuous operation time in pure heating or pure cooling mode reaches the preset duration, the system automatically exits the current pure temperature control mode and enters a power-off state or jumps to another corresponding state based on the current battery status.

[0034] The system determines whether to enter deep low-temperature heating (pure heating), medium-low temperature heating (heating while charging), or pure charging mode based on the battery's initial lowest temperature. Different modes correspond to different heating power levels and control logic.

[0035] When the battery's initial minimum temperature is less than or equal to the first temperature threshold and the battery's state of charge is less than or equal to the first state of charge threshold, the system enters deep low-temperature heating mode. In deep low-temperature heating mode, a low-current charging circuit is first established. Then, a first-level heating request command is sent to the vehicle controller. The vehicle controller then starts the heating unit. Simultaneously, dynamic current control logic is used to adjust the charging current.

[0036] When the battery's initial minimum temperature is greater than the first temperature threshold but less than or equal to the second temperature threshold, and the battery's state of charge (SOC) is less than or equal to the first SOC threshold, the system enters the medium-low temperature heating mode. In this mode, a first-level heating request command is sent to the vehicle controller. The vehicle controller then activates the heating unit. Simultaneously, the heating power level is adjusted in real-time based on changes in battery temperature. When the battery temperature rises to the third temperature threshold, the heating request is deactivated.

[0037] When the initial minimum battery temperature exceeds the second temperature threshold, it is determined that there is no need for heating. The battery then directly enters pure charging mode.

[0038] When the battery's initial maximum temperature is greater than or equal to the third temperature threshold, it enters a pure cooling state. In pure cooling mode, a cooling request command is sent to the vehicle controller. The vehicle controller then activates the cooling unit. The battery heating controller continuously monitors battery temperature changes. When the battery's maximum temperature drops to the fourth temperature threshold, pure cooling is considered complete. After pure cooling is complete, the battery heating controller enters a simultaneous cooling and charging state.

[0039] Step Six: Temperature Control and Charging Simultaneously. Once the battery temperature reaches the first preset threshold, it enters the temperature control and charging simultaneously. In this state, both the temperature regulation system and the charging system operate concurrently. The high-voltage switch status during this state is as follows: positive switch closed, negative switch closed, pre-charge switch open, and fast-charge switch closed.

[0040] In the simultaneous temperature control and charging mode, the battery heating controller adjusts the temperature regulation power and charging current in real time according to changes in battery temperature. While ensuring the battery temperature remains within a safe range, the charging power is gradually increased. When the battery temperature reaches the second preset threshold, the temperature regulation system is shut down, and the system enters pure charging mode.

[0041] Step 7: Pure charging state. Once the battery temperature reaches the second preset threshold, it enters pure charging state. In pure charging state, full-power fast charging is performed. The high-voltage switch status in pure charging state is the same as in the temperature-controlled charging state: positive switch closed, negative switch closed, pre-charge switch open, and fast charging switch closed.

[0042] In pure charging mode, the battery heating controller sends maximum charging voltage and current commands to the charging station based on the battery's state of charge and temperature. The charging station outputs the corresponding charging power according to the received commands. The battery heating controller continuously monitors the battery status and the charging process. When the battery's state of charge reaches a preset value or a fault occurs, the charging process ends, and the device enters the power-off state.

[0043] Step 8: Power-off state. The battery enters the power-off state upon completion of charging or detection of a fault. In the power-off state, the battery heating controller controls the high-voltage switch group to disconnect all high-voltage switches according to a preset sequence. First, the fast-charging switch is disconnected, then the positive switch is disconnected, and finally the negative switch is disconnected. The pre-charge switch remains open.

[0044] After all high-voltage switches are disconnected, the battery heating controller records the operational data for this charging process. This includes charging start time, charging end time, charging capacity, battery temperature change curve, and fault information. After data recording is complete, the battery heating controller enters sleep mode.

[0045] The present invention also includes special handling steps for battery swapping scenarios. When the battery heating controller receives a message from the vehicle controller indicating that the mode switching status level is greater than or equal to the ready state, it performs the following operations within a preset time.

[0046] First, unconditionally set thermal management requests to a no-demand state. Second, maintain a no-demand thermal management state throughout the battery swapping process. Third, suspend collision fault diagnosis operations. Fourth, suspend high-voltage interlock signal detection operations. Collision fault diagnosis operations include hard-wired collision signal detection and controller area network collision signal detection.

[0047] After the battery swapping process is complete, the vehicle controller sends a mode switching completion message. Upon receiving the message, the battery heating controller resumes its collision fault diagnosis and high-voltage interlock signal detection functions. Simultaneously, it determines whether to restart the thermal management system based on the current vehicle status.

[0048] In pure heating mode, the deep low-temperature heating mode employs dynamic current control logic to regulate the charging current. The dynamic current control logic is implemented using the following formula: ; in, This indicates a request for charging current, measured in amperes. This indicates the initial charging current, in amperes. This represents the current adjustment rate coefficient. This indicates the maximum permissible charging current, measured in amperes. This indicates the current actual charging current of the busbar, in amperes.

[0049] The initial charging current is determined based on the battery's minimum temperature and state of charge. The current adjustment rate factor is set to 1 ampere per second. The maximum allowable charging current is pre-calibrated based on the battery model and low-temperature charging characteristics.

[0050] When the bus charging current is greater than or equal to 5 amps, the requested charging current decreases according to the current adjustment rate coefficient. When the bus charging current is less than 1 amp, the requested charging current increases according to the current adjustment rate coefficient. This continues until the charging current stabilizes within a preset range. The preset range is greater than or equal to 1 amp and less than 5 amps.

[0051] Dynamic current control logic can avoid lithium dendrite precipitation caused by low-temperature high-current charging. It also ensures the stability and safety of the charging process.

[0052] In temperature-controlled conditions, a graded power heating control method is employed. This method adjusts the heating power level in real time based on the battery temperature and temperature difference. In pure temperature-controlled conditions, there is a level 3 full-power heating (suitable for low temperatures and large temperature differences) and a level 2 power heating (suitable for medium-temperature conditions). The heating power levels are divided into three levels: Level 1, Level 2, and Level 3. Different power levels correspond to different output power of the heating unit.

[0053] When the battery's lowest temperature is less than or equal to the fourth temperature threshold and the battery temperature difference is greater than or equal to the preset temperature difference threshold, level three heating is activated. Level three heating is the highest power heating. When the battery's lowest temperature is greater than the fourth temperature threshold but less than or equal to the fifth temperature threshold, or when the battery temperature difference is less than the preset temperature difference threshold, level two heating is activated. When the battery's lowest temperature is greater than the fifth temperature threshold but less than or equal to the sixth temperature threshold, level one heating is activated. When the battery's lowest temperature is greater than the sixth temperature threshold, the heating system is deactivated.

[0054] The graded power heating control method enables precise temperature control, while simultaneously reducing overall vehicle energy consumption and improving heating efficiency.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for controlling thermal management during fast charging of electric vehicles, characterized in that, Includes the following steps: Step 1: Perform initialization. The battery management system completes the initialization of the entire battery system and performs self-tests on switches, sensors, and communication modules. All high-voltage switches remain open. Step 2: After the self-test passes, it enters the standby state, waits for the vehicle controller to give instructions and determine the battery temperature. If the self-test fails, it will directly enter the power-down state. Step 3: When the preset conditions are met, start the pre-charge operation and control the corresponding high-voltage switch to close to complete the high-voltage circuit pre-charge; Step 4: After pre-charging is completed, the system enters a transition state, adjusting the high-voltage switch status to prepare for the temperature control and charging phase. Step 5: Based on the battery temperature determination result, enter pure temperature control state, simultaneous temperature control and charging state, or pure charging state respectively. When entering pure temperature control mode, the battery heating or cooling system is controlled to operate to regulate the battery temperature; Step 6: Once the battery temperature reaches the first preset threshold under pure temperature control, it enters a state of simultaneous temperature control and charging, where temperature adjustment and charging operations are performed at the same time. Step 7: Once the battery temperature reaches the second preset threshold while the battery is under temperature control and charging conditions, it enters pure charging mode and performs full-power fast charging. Step 8: When charging is complete or a fault is detected, enter the power-off state, disconnect all high-voltage switches and record the operating data.

2. The method for controlling the thermal management of fast charging of an electric vehicle according to claim 1, characterized in that, The pure temperature control state includes a pure heating state. In this state, a graded power heating control method is used: Level 3 full-power heating (suitable for low temperatures and large temperature differences) and Level 2 power heating (suitable for medium temperature conditions). The heating power level is primarily determined by the current battery temperature, while simultaneously adjusting the charging current using dynamic current control logic. This dynamic current control logic is implemented using the following formula: ,in, This indicates a requested charging current, in amperes. This indicates the initial charging current, in amperes. This represents the current adjustment rate coefficient, with a value of 1 ampere per second; This indicates the maximum permissible charging current, measured in amperes. This indicates the current actual charging current of the busbar, in amperes. When the busbar charging current is greater than or equal to 5 amperes, the charging current is requested to decrease according to the current adjustment rate coefficient. When the busbar charging current is less than 1 ampere, the charging current is requested to increase according to the current adjustment rate coefficient until the charging current stabilizes within the preset range.

3. The method for controlling the thermal management of fast charging of an electric vehicle according to claim 1, characterized in that, It also includes special handling steps for battery swapping scenarios. When the battery heating controller receives a message from the vehicle controller that the mode switching status level is greater than or equal to the ready state, it performs the following operations within a preset time: unconditionally set the thermal management request to the no-demand state, maintain the thermal management no-demand state throughout the battery swapping process, suspend the collision fault diagnosis operation, and suspend the high-voltage interlock signal detection operation. The collision fault diagnosis operation includes hard-wired collision signal detection and controller area network collision signal detection.

4. The method for controlling the thermal management of fast charging of an electric vehicle according to claim 1, characterized in that, The pure temperature control state includes pure heating state and pure cooling state. Both pure heating state and pure cooling state are equipped with an overtime protection mechanism. When the continuous running time of pure heating state or pure cooling state reaches the preset duration, the current pure temperature control state will be automatically exited and the state will be entered into power-off state or jump to other corresponding states according to the current battery status.

5. The method for controlling the thermal management of fast charging of an electric vehicle according to claim 1, characterized in that, The preset conditions for initiating the pre-charging operation in step three include: the vehicle controller sends a charging permission command, the battery heating controller has no serious charging fault, the vehicle is only plugged into a DC charging gun, the battery heating controller completes fast charging interaction with the charging pile and sends a corresponding interaction signal, the battery temperature determination result indicates that temperature adjustment is required, and the high-voltage switch status during the pre-charging operation is: negative switch closed, pre-charging switch closed, positive switch open, and fast charging switch open.

6. The method for controlling the thermal management of fast charging of an electric vehicle according to claim 1, characterized in that, In step four, the high-voltage switch states in the transition state are: positive switch closed, negative switch closed, pre-charge switch open, and fast-charge switch open. The transition state is used to complete the high-voltage circuit state switching from the pre-charge stage to the pure temperature control stage, avoiding the impact of sudden changes in the high-voltage circuit state on the battery and electrical components, and ensuring the stable operation of the high-voltage circuit in the subsequent temperature control stage.

7. The method for controlling the thermal management of fast charging of an electric vehicle according to claim 1, characterized in that, In step five, the high-voltage switch status in the pure temperature control state is: negative switch closed, fast charging switch closed, positive switch open, and pre-charge switch open. In the pure temperature control state, only the battery temperature regulation system is running and no charging operation is performed. The battery temperature determination in step five is based on the initial lowest battery temperature. The determination result corresponds to entering the deep low temperature heating (pure heating), medium low temperature heating (heating while charging), or pure charging state. Different states correspond to different heating power levels and control logic.

8. The method for controlling the thermal management of fast charging of an electric vehicle according to claim 1, characterized in that, In step six, the high-voltage switch states during the simultaneous temperature control and charging process are: positive switch closed, negative switch closed, pre-charge switch open, and fast-charge switch closed. During this process, the temperature regulation system and the charging system operate simultaneously, adjusting the temperature regulation power and charging current in real time according to changes in battery temperature, and gradually increasing the charging power while ensuring that the battery temperature remains within a safe range.

9. The method for controlling the thermal management of fast charging of an electric vehicle according to claim 1, characterized in that, The pure temperature control state includes a pure cooling state, and the pure cooling process is logically consistent with the heating process: after the battery management system is woken up, it completes an initialization self-test. After the self-test passes, it enters a standby state. After the pre-charging conditions are met, the pre-charging operation is started. After the pre-charging is completed, it enters a transition state. Depending on the battery temperature determination result, it enters a pure cooling state, a cooling-while-charging state, or a pure charging state. When the battery temperature meets the pure cooling conditions, it enters a pure cooling state. After pure cooling is completed and the voltage conditions are met, it enters a cooling-while-charging state. After the battery temperature reaches the standard, it enters a pure charging state.

10. A fast-charging thermal management control system for electric vehicles, characterized in that, The electric vehicle fast-charging thermal management control method applicable to any one of claims 1 to 9 includes a battery heating controller, a vehicle controller, a high-voltage switch group, a temperature regulation system, and a charging interaction module. The battery heating controller is communicatively connected to the vehicle controller, the high-voltage switch group, the temperature regulation system, and the charging interaction module. The high-voltage switch group includes a positive switch, a negative switch, a pre-charge switch, and a fast-charge switch. The battery heating controller controls the timing of the high-voltage switch group and the operating status of the temperature regulation system according to the vehicle controller's instructions, the charging gun status, the battery temperature, the battery voltage, and the fault status.

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