Vehicle low-temperature heat management control method and device, vehicle and storage medium

Abstract

The embodiment of the invention provides a vehicle low-temperature heat management control method and device, a vehicle and a storage medium. The method comprises the following steps that the temperature of the environment where the vehicle is located, the module temperature of a power battery and the maximum allowable charging power are obtained; based on the environment temperature, the module temperature and the maximum allowable charging power, the vehicle is controlled to enter a low-temperature heat management working condition, and the braking energy recovery torque of the vehicle is determined according to the motor rotating speed and the maximum allowable charging power; based on the braking energy recovery torque and the motor rotating speed, the driving motor is controlled to execute the braking energy recovery action, meanwhile, the working efficiency of the driving motor is adjusted to generate heat, and the cooling system heats the power battery through the heat. On the premise that the safety of the battery is guaranteed, optimization of braking torque limitation is achieved, and the problems that in the related technology, due to the fact that the motor braking torque in the low-temperature environment is strictly limited and excessively depends on a mechanical braking system, the energy utilization efficiency of the whole vehicle is reduced, and abrasion of the braking system is aggravated are solved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of vehicle power system control, and particularly relate to a vehicle low-temperature thermal management control method and device, a vehicle, and a storage medium. BACKGROUND

[0002] In related technologies, a vehicle uses a driving motor as a core power source to realize vehicle driving by converting power battery electric energy into mechanical energy. The driving motor has two working states: an electric driving state and a power generation state (energy recovery). In the electric driving state, the driving motor converts electric energy into mechanical energy to drive the vehicle. In the power generation state (energy recovery), the driving motor converts mechanical energy into electric energy to charge the battery. This process is mainly implemented in braking or coasting conditions, which can effectively improve energy utilization efficiency and extend the cruising range.

[0003] Currently, a lithium-ion power battery is generally used as an energy storage component in a vehicle. However, due to the current development status of battery technology, the lithium-ion power battery has a charging and discharging performance decay problem in a low-temperature working condition. The system must strictly limit the braking torque output by the motor in energy recovery to prevent excessive charging power from damaging the battery. When the driver implements braking, the vehicle has to rely more on the mechanical braking system to make up for the braking force due to the limited motor braking force, resulting in the dissipation of the recoverable kinetic energy in the form of heat energy, which not only reduces the energy utilization efficiency but also accelerates the wear of the braking system. This seriously hinders the performance improvement of the vehicle in a low-temperature working condition. SUMMARY

[0004] Embodiments of the present application provide a vehicle low-temperature thermal management control method and device, a vehicle, and a storage medium, which aim to improve the problems in related technologies that the motor braking torque is forced to be strictly limited in a low-temperature environment, the vehicle energy utilization efficiency is reduced, and the wear of the braking system is accelerated due to excessive dependence on the mechanical braking system.

[0005] The first aspect of the present application provides a vehicle low-temperature thermal management control method, including the following steps: a vehicle includes a power battery, a driving motor, and a cooling system, and the power battery and the driving battery share the cooling system. The method includes the following steps: obtaining an ambient temperature of the vehicle, a module temperature of the power battery, and a maximum allowed charging power; based on the ambient temperature, the module temperature, and the maximum allowed charging power, controlling the vehicle to enter a low-temperature thermal management working condition, determining a braking energy recovery torque of the vehicle according to a motor speed and the maximum allowed charging power; based on the braking energy recovery torque and the motor speed, controlling the driving motor to perform a braking energy recovery action while adjusting the working efficiency of the driving motor to generate heat, and the cooling system uses the heat to heat the power battery.

[0006] Based on the aforementioned technical means, this embodiment of the application can first control the vehicle to enter a low-temperature thermal management condition based on key parameters such as ambient temperature, battery module temperature, and charging capacity, and determine the vehicle's regenerative braking torque according to motor speed and maximum allowable charging power. Then, by controlling the working efficiency of the drive motor, controllable heat is generated while achieving regenerative braking. Finally, the generated heat is used by the cooling system to heat the power battery, achieving effective utilization of thermal energy. This method, by intelligently adjusting the working efficiency of the motor during braking, achieves efficient regeneration of braking energy while ensuring battery safety, improves the low-temperature performance of the battery by utilizing the generated waste heat, and reduces the load on the mechanical braking system, effectively solving problems such as low energy recovery efficiency and severe wear of the braking system in low-temperature environments.

[0007] Optionally, based on the regenerative braking torque and motor speed, while controlling the drive motor to perform regenerative braking action, the operating efficiency of the drive motor is adjusted to generate heat, including: obtaining a pre-calibrated current lookup table of the drive motor under low-temperature thermal management conditions, wherein the operating efficiency of the drive motor is lower than a preset efficiency when the current lookup table is calibrated; using the regenerative braking torque and motor speed as indexes, querying the current lookup table to obtain the current command of the drive motor; and controlling the drive motor using the current command.

[0008] Based on the aforementioned technical means, this application embodiment can control the drive motor to perform regenerative braking while simultaneously adjusting the drive motor's operating efficiency to generate heat, based on the regenerative braking torque and motor speed. Specifically, firstly, a current command is obtained using a pre-calibrated current lookup table under low-temperature conditions, indexed by the regenerative braking torque and motor speed; then, the drive motor is controlled according to this command, so that it generates the required heat by reducing its operating efficiency while performing regenerative braking. This solution can improve the battery's low-temperature performance by utilizing the waste heat generated by the motor, while reducing the use of mechanical braking, effectively solving problems such as low vehicle energy recovery efficiency and severe wear of the braking system in low-temperature environments, all while ensuring braking performance.

[0009] Optionally, the regenerative braking torque of the vehicle is determined based on the motor speed and the maximum allowable charging power, including: determining the initial value of the regenerative braking torque of the drive motor based on the motor speed; determining the maximum allowable regenerative braking torque of the power battery based on the motor speed and the maximum allowable charging power; if the initial value of the regenerative braking torque is less than the maximum allowable regenerative braking torque, then the initial value of the regenerative braking torque is used as the regenerative braking torque; if the initial value of the regenerative braking torque is greater than or equal to the maximum allowable regenerative braking torque, then the initial value of the regenerative braking torque is used as the regenerative braking torque.

[0010] Based on the aforementioned technical means, the embodiments of this application can determine the regenerative braking torque of a vehicle according to the motor speed and the maximum allowable charging power. Specifically, an initial value of the regenerative braking torque can be determined based on the motor speed, and the maximum allowable regenerative braking torque of the power battery can be determined based on the motor speed and the maximum allowable charging power. By comparing these two torque values, the final regenerative braking torque is intelligently selected to ensure optimal energy recovery within the battery's safe operating range.

[0011] Optionally, determining the initial value of the energy recovery torque of the drive motor based on the motor speed includes: obtaining a pre-calibrated energy recovery torque lookup table for the drive motor; and querying the energy recovery torque lookup table using the motor speed as an index to obtain the initial value of the energy recovery torque.

[0012] Based on the aforementioned technical means, this application embodiment can determine the initial value of the energy recovery torque of the drive motor according to the motor speed. Specifically, the initial value of the energy recovery torque is directly obtained by using a pre-calibrated torque lookup table with the motor speed as the index. This method determines the initial value of the energy recovery torque through a table lookup, so that it can be compared with the maximum allowable recovery torque value of the power battery. By comparing these two torque values, the final braking energy recovery torque is intelligently selected to ensure that the optimal energy recovery effect is achieved within the battery's safety range.

[0013] Optionally, the formula for calculating the maximum permissible regenerative torque is:

[0014] Among them, T Batt-Max P represents the maximum permissible regenerative torque. CHG Indicates the maximum allowable charging power, V E This indicates the motor speed.

[0015] Optionally, based on ambient temperature, module temperature, and maximum allowable charging power, the vehicle is controlled to enter a low-temperature thermal management condition, including: if the ambient temperature is lower than a first temperature threshold, the module temperature is lower than a second temperature threshold, and the maximum allowable charging power is lower than a power threshold, then the vehicle is controlled to enter a low-temperature thermal management condition.

[0016] Based on the aforementioned technical means, the embodiments of this application can achieve low-temperature operating condition determination through the following steps: when the ambient temperature is lower than a first temperature threshold, the module temperature is lower than a second temperature threshold, and the maximum allowable charging power is lower than a power threshold simultaneously, the vehicle is controlled to enter a low-temperature thermal management operating condition. This method ensures that the system starts under low-temperature operating conditions where the vehicle requires low-temperature thermal management through multiple parameter determinations, thus protecting battery safety and avoiding unnecessary energy consumption.

[0017] Optionally, before determining the vehicle's regenerative braking torque based on the motor speed and maximum allowable charging power, the method further includes: acquiring the vehicle's current gear, brake pedal status, accelerator pedal status, and vehicle fault status; and controlling the vehicle to enter the regenerative braking state based on the current gear, brake pedal status, accelerator pedal status, and vehicle fault status.

[0018] Based on the aforementioned technical means, the embodiments of this application can achieve energy recovery condition determination through the following steps: First, before determining the vehicle's braking energy recovery torque based on the motor speed and maximum allowable charging power, key parameters such as gear position, pedal status, and fault information are acquired. Then, based on these parameters, a comprehensive judgment is made as to whether the energy recovery conditions are met. This method, through multi-dimensional state monitoring, ensures that the vehicle enters the braking energy recovery condition when the conditions are met, thus guaranteeing driving safety and optimizing energy recovery efficiency.

[0019] A second aspect of this application provides a vehicle low-temperature thermal management control device, including: a power battery, a drive motor, and a cooling system. The power battery and the drive battery share the same cooling system. The device includes: an acquisition module for acquiring the ambient temperature of the vehicle, the module temperature of the power battery, and the maximum allowable charging power; a determination module for controlling the vehicle to enter a low-temperature thermal management condition based on the ambient temperature, module temperature, and maximum allowable charging power, and determining the vehicle's regenerative braking torque based on the motor speed and the maximum allowable charging power; and a control module for controlling the drive motor to perform regenerative braking actions based on the regenerative braking torque and motor speed, while adjusting the drive motor's operating efficiency to generate heat, and the cooling system using the heat to heat the power battery.

[0020] Optionally, the control module is further configured to: obtain a pre-calibrated current lookup table of the drive motor under low-temperature thermal management conditions, wherein the working efficiency of the drive motor is lower than the preset efficiency when the current lookup table is calibrated; obtain the current command of the drive motor by querying the current lookup table using the braking energy recovery torque and motor speed as indexes; and control the drive motor using the current command.

[0021] Optionally, the determining module is further configured to: determine the initial value of the energy recovery torque of the drive motor based on the motor speed; determine the maximum allowable recovery torque of the power battery based on the motor speed and the maximum allowable charging power; if the initial value of the energy recovery torque is less than the maximum allowable recovery torque, then the initial value of the energy recovery torque is used as the braking energy recovery torque; if the initial value of the energy recovery torque is greater than or equal to the maximum allowable recovery torque, then the initial value of the energy recovery torque is used as the braking energy recovery torque.

[0022] Optionally, the determining module is further configured to determine the initial value of the energy recovery torque of the drive motor based on the motor speed, including: obtaining a pre-calibrated energy recovery torque lookup table of the drive motor; and querying the energy recovery torque lookup table using the motor speed as an index to obtain the initial value of the energy recovery torque.

[0023] Optionally, the formula for calculating the maximum permissible regenerative torque is:

[0024] Among them, T Batt-Max P represents the maximum permissible regenerative torque. CHG Indicates the maximum allowable charging power, V E This indicates the motor speed.

[0025] Optionally, the determining module is further configured to control the vehicle to enter a low-temperature thermal management condition if the ambient temperature is lower than a first temperature threshold, the module temperature is lower than a second temperature threshold, and the maximum allowable charging power is lower than a power threshold.

[0026] Optionally, it also includes a determination module, used to obtain the vehicle's current gear, brake pedal state, accelerator pedal state, and vehicle fault state before determining the vehicle's regenerative braking torque based on the motor speed and maximum allowable charging power; and to control the vehicle to enter the regenerative braking state based on the current gear, brake pedal state, accelerator pedal state, and vehicle fault state.

[0027] A third aspect of this application provides a vehicle, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the vehicle low-temperature thermal management control method as described in the above embodiments.

[0028] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the vehicle low-temperature thermal management control method as described in the above embodiments.

[0029] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0030] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a diagram of the architecture of an electric vehicle thermal management system according to an embodiment of this application; Figure 2 This is a flowchart of a vehicle low-temperature thermal management control method according to an embodiment of this application; Figure 3 This is a diagram illustrating the implementation of thermal management control logic for electric vehicles operating at low temperatures, according to an embodiment of this application. Figure 4 This is a block diagram of a vehicle low-temperature thermal management control device according to an embodiment of this application; Figure 5 This is a structural schematic diagram of a vehicle provided according to an embodiment of this application. Detailed Implementation

[0031] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0032] Currently, vehicles use drive motors as the core of their power output to achieve driving functions, and during vehicle operation, energy is entirely derived from the onboard power battery. The vast majority of vehicles, both domestically and internationally, use lithium-ion power batteries as their energy storage components. However, due to the current state of battery technology development, the problem of performance degradation in the charge and discharge cycles of lithium-ion power batteries under low-temperature conditions has not yet been overcome, thus becoming a serious obstacle to improving the low-temperature performance of vehicles.

[0033] Compared to traditional gasoline-powered vehicles, electric vehicles' drive motors have two operating modes: electric and generator. When driving force is needed to propel the vehicle forward or backward, the drive motor operates in electric mode, converting the electrical energy from the battery into mechanical energy. When the drive system needs to generate braking force, the motor operates in generator mode, converting the mechanical energy generated during rotation into electrical energy to charge the battery. This process of converting mechanical energy into electrical energy is called energy recovery. For electric vehicles, energy recovery control is generally implemented during braking or coasting. This recovers the electrical energy generated while the drive motor produces braking torque, thereby improving energy efficiency and extending the vehicle's driving range.

[0034] In related technologies, the charging and discharging performance of vehicle lithium-ion power batteries degrades significantly in low-temperature environments. This necessitates strict limitations on the braking torque output of the motor during energy recovery control of the drive system to prevent damage to the vehicle's power battery due to excessive charging power generated by energy recovery. Under these conditions, when the driver requires braking, the braking torque generated by the motor is strictly limited, necessitating the vehicle's mechanical braking system to produce a greater braking torque. This braking torque is generated through internal friction within the brakes (such as friction between the hydraulic brake caliper and the brake disc) and is dissipated as heat.

[0035] The following description, with reference to the accompanying drawings, outlines a vehicle low-temperature thermal management control method, apparatus, vehicle, and storage medium according to embodiments of this application. Addressing the issues mentioned in the background art, such as the forced and strict limitation of motor braking torque in low-temperature environments, leading to excessive reliance on mechanical braking systems, resulting in decreased vehicle energy utilization efficiency and accelerated wear of the braking system, this application provides a thermal management control method for electric vehicles under low-temperature conditions. This method is implemented based on an electric vehicle controller, a battery management system, a motor controller, and the vehicle's cooling system.

[0036] In this method, the vehicle controller first determines whether the vehicle has entered a low-temperature thermal management condition based on the ambient temperature and the maximum allowable charging and discharging power output by the battery management system. Once the conditions are met and the vehicle enters this condition, the vehicle controller determines whether to enter an energy recovery state based on information such as the vehicle's gear position and brake pedal status, and calculates the braking torque allocated to the drive motor. The motor controller receives the torque command and the command to enter the low-temperature thermal management condition from the vehicle controller. Then, by reducing the efficiency of the drive system, it controls the drive motor to output the expected braking torque. During this process, the additional heat generated by the reduced efficiency enters the cooling system shared by the power battery and the drive system, utilizing waste heat to heat the power battery. This solves the problems in related technologies where the braking torque of the motor in a low-temperature environment is forcibly limited, leading to excessive reliance on the mechanical braking system, resulting in decreased vehicle energy utilization efficiency and accelerated wear of the braking system.

[0037] Figure 1 This is an architecture diagram of an electric vehicle thermal management system according to an embodiment of this application, such as... Figure 1 As shown, the cooling cycle system of an electric vehicle includes: a drive system, a battery system, and a cooling system.

[0038] The drive system consists of a drive motor and a motor controller, the battery system consists of a battery management system and a power battery, and the cooling system consists of a water pump, a coolant tank, a radiator, and a fan. Driven by the water pump, the coolant in the coolant tank flows through these systems, achieving heat exchange and meeting the cooling and heating needs of the vehicle components. Figure 1 The vehicle controller controls the battery management system, motor controller, and radiator and fan in the cooling system to ensure that the thermal management control method for electric vehicles under low-temperature conditions provided in this application is executed normally.

[0039] The following will be based on Figure 1 The structure shown illustrates the vehicle's low-temperature thermal management control method, such as... Figure 2 As shown, it includes the following steps: In step S201, the ambient temperature of the vehicle, the module temperature of the power battery, and the maximum allowable charging power are obtained.

[0040] It is understood that the embodiments of this application use these three factors as the triggering criteria for low-temperature thermal management control, and provide a data basis for subsequent control decisions by monitoring these three key parameters (ambient temperature, battery temperature, and charging capability) in real time.

[0041] Specifically, such as Figure 1 As shown, the vehicle controller, as the core component controlling the normal execution of various vehicle functions, has abundant interface resources and can obtain various status parameters of the vehicle. The vehicle controller obtains the ambient temperature of the vehicle through sensors; the specific type and implementation of the sensors are not limited. The vehicle controller obtains the module temperature and maximum allowable charging power of the power battery through the battery management system; the method of acquiring this data is not specifically limited.

[0042] In step S202, based on the ambient temperature, module temperature and maximum allowable charging power, the vehicle is controlled to enter the low-temperature thermal management condition, and the vehicle's regenerative braking torque is determined according to the motor speed and maximum allowable charging power.

[0043] It is understood that, according to the obtained ambient temperature, module temperature and maximum allowable charging power, the embodiment of this application can determine that the vehicle has entered a low temperature thermal management condition based on the judgment conditions. Then, when the vehicle enters the energy recovery state, the vehicle controller determines the vehicle's braking energy recovery torque based on the current state of the vehicle, the motor speed and the maximum allowable charging power, so as to subsequently control the drive motor according to the expected torque to realize efficiency adjustment and waste heat utilization.

[0044] In this embodiment of the application, the vehicle is controlled to enter a low-temperature thermal management condition based on the ambient temperature, module temperature and maximum allowable charging power, including: if the ambient temperature is lower than a first temperature threshold, the module temperature is lower than a second temperature threshold and the maximum allowable charging power is lower than a power threshold, then the vehicle is controlled to enter a low-temperature thermal management condition.

[0045] The first temperature threshold is the vehicle ambient temperature threshold T. Veh ℃, which is the critical value of the vehicle's ambient temperature; the second temperature threshold is the power battery module temperature threshold T. Batt ℃, which is the critical temperature value of the power battery module; the power threshold is the maximum allowable charging power threshold P of the power battery. CHG kW, which is the critical value of the maximum allowable charging power of the power battery. First temperature threshold T Veh ℃, second temperature threshold T Batt ℃ and power threshold P CHG The specific value of kW can be specifically specified, and this application does not impose any specific limitations.

[0046] It is understood that the embodiments of this application can achieve low-temperature operating condition determination through the following steps: when the ambient temperature is lower than a first temperature threshold, the module temperature is lower than a second temperature threshold, and the maximum allowable charging power is lower than a power threshold, the vehicle is controlled to enter a low-temperature thermal management operating condition. This method ensures that the system starts under low-temperature operating conditions where the vehicle requires low-temperature thermal management through multiple parameter determinations, thus ensuring battery safety and avoiding unnecessary energy consumption.

[0047] Specifically, a vehicle is considered to have entered low-temperature thermal management mode when all of the following conditions are met: ① The ambient temperature of the vehicle is lower than the first temperature threshold T Veh ℃; ② The temperature of the power battery module is lower than the second temperature threshold T Batt ℃ ③ The maximum allowable charging power of the power battery is less than the power threshold P. CHG kW.

[0048] Of the above conditions, the second temperature threshold is determined based on the technical parameters of the electric vehicle's power battery. When the temperature is below the second temperature threshold, it indicates that the low-temperature environment will severely affect the output performance of the power battery. For ternary lithium-ion power batteries, their low-temperature performance is better than that of lithium iron phosphate power batteries; therefore, the second temperature threshold for ternary lithium-ion power batteries is lower than that for lithium-ion power batteries. The power threshold is determined based on the vehicle's energy recovery performance. When the maximum allowable charging power of the power battery is lower than this threshold, it indicates that the vehicle's energy recovery function is strictly limited. At this time, the power battery cannot be charged at high power through energy recovery to avoid battery damage.

[0049] In this embodiment of the application, before determining the vehicle's regenerative braking torque based on the motor speed and the maximum allowable charging power, the method further includes: acquiring the vehicle's current gear, brake pedal state, accelerator pedal state, and vehicle fault state; and controlling the vehicle to enter the regenerative braking mode based on the current gear, brake pedal state, accelerator pedal state, and vehicle fault state.

[0050] It is understood that the energy recovery condition determination in this application embodiment can be achieved through the following steps: First, before determining the vehicle's braking energy recovery torque based on the motor speed and maximum allowable charging power, key parameters such as gear position, pedal status, and fault information are acquired. Then, based on these parameters, a comprehensive judgment is made as to whether the energy recovery conditions are met. This method, through multi-dimensional state monitoring, ensures that the vehicle enters the braking energy recovery condition when the conditions are met, thus guaranteeing driving safety and optimizing energy recovery efficiency.

[0051] Specifically, for electric vehicles, the energy recovery function is activated under the following two driving conditions: first, during vehicle coasting when the accelerator pedal is not depressed, and the driver has no need for power output or a need to decelerate the vehicle based on coasting; second, during vehicle braking, when the driver needs to decelerate and brake. Details are as follows: (1) Judgment of entering the sliding energy recovery state: When the following conditions are met, the vehicle is deemed to be allowed to enter the sliding energy recovery state: ① The vehicle's strategic gear is forward; ②The vehicle did not experience any immediate high-voltage disconnection fault, delayed high-voltage disconnection fault, irrecoverable zero torque fault, or limp fault; ③ The driver did not press the brake pedal; ④ The driver did not press the accelerator pedal.

[0052] (2) Determining whether to enter the regenerative braking state: The vehicle is allowed to enter the regenerative braking state when the following conditions are met: ① The vehicle's strategic gear is forward; ②The vehicle did not experience any immediate high-voltage disconnection fault, delayed high-voltage disconnection fault, irrecoverable zero torque fault, or limp fault; ③ The driver presses the brake pedal; ④ The driver did not press the accelerator pedal.

[0053] In this embodiment of the application, determining the vehicle's regenerative braking torque based on the motor speed and the maximum allowable charging power includes: determining the initial value of the regenerative braking torque of the drive motor based on the motor speed; determining the maximum allowable regenerative braking torque of the power battery based on the motor speed and the maximum allowable charging power; if the initial value of the regenerative braking torque is less than the maximum allowable regenerative braking torque, then the initial value of the regenerative braking torque is used as the regenerative braking torque; if the initial value of the regenerative braking torque is greater than or equal to the maximum allowable regenerative braking torque, then the initial value of the regenerative braking torque is used as the regenerative braking torque.

[0054] It is understood that the embodiments of this application can determine the vehicle's regenerative braking torque based on the motor speed and the maximum allowable charging power. An initial value of the regenerative braking torque can be determined based on the motor speed, and the maximum allowable regenerative braking torque of the power battery can be determined based on the motor speed and the maximum allowable charging power. By comparing these two torque values, the final regenerative braking torque is intelligently selected to ensure optimal energy recovery within the battery's safe range. In this step, the vehicle controller calculates the energy recovery torque requirement and the braking torque allocated to the drive motor based on the vehicle's current state.

[0055] The formula for calculating the maximum permissible recovery torque is as follows:

[0056] Among them, T Batt-Max P represents the maximum permissible regenerative torque. CHG Indicates the maximum allowable charging power, V E This indicates the motor speed.

[0057] Specifically, after obtaining the initial value of the energy recovery torque, here the initial value of the energy recovery torque is denoted as T. Reg-Int This indicates that the braking torque allocated to the drive system is determined based on the state of the power battery, and the formula for calculating the allocation is as follows:

[0058] in, This indicates the braking torque allocated to the drive system. The braking torque allocated to the drive system will not exceed the maximum allowable charging power of the power battery. Figure 3 The thermal management control logic for electric vehicles operating in low-temperature conditions, as shown, controls the drive motor.

[0059] In this embodiment of the application, determining the initial value of the energy recovery torque of the drive motor based on the motor speed includes: obtaining a pre-calibrated energy recovery torque lookup table for the drive motor; and querying the energy recovery torque lookup table using the motor speed as an index to obtain the initial value of the energy recovery torque.

[0060] It is understood that the embodiments of this application can determine the initial value of the energy recovery torque of the drive motor based on the motor speed. The initial value of the energy recovery torque is directly obtained by using a pre-calibrated torque lookup table, indexed by the motor speed. This method determines the initial value of the energy recovery torque through a table lookup, so that it can be compared with the maximum allowable recovery torque value of the power battery. By comparing these two torque values, the final braking energy recovery torque is intelligently selected to ensure optimal energy recovery within the battery's safety range.

[0061] Specifically, for electric vehicle controllers, the RAM (Random Access Memory) storage resources of their internal main control chip are extremely valuable, generally making it impossible to compute complex driver models while ensuring the normal execution of the vehicle control strategy. In contrast to the RAM resources of the vehicle controller, its internal ROM (Read-Only Memory) storage resources are more abundant, capable of storing large-scale tabular data. Taking advantage of this characteristic of the vehicle controller, this application calculates the braking torque of the drive motor under energy recovery conditions based on a table lookup method. The formula for calculating the energy recovery torque is:

[0062] Among them, T Reg-IntIndicates the initial value of the current energy recovery torque; K Level This indicates the energy recovery intensity, which is obtained based on the driver's actions regarding the vehicle's energy recovery intensity via physical or virtual buttons; T Reg This represents the base energy recovery torque, which is the motor speed V. E The function. In fact, T Reg-Int The specific values ​​are obtained by looking up a table, as shown in Table 1. Table 1 is a lookup table for energy recovery torque based on motor speed.

[0063] Table 1

[0064] Table 1 establishes the energy recovery torque T through actual vehicle calibration. Reg-Int The mapping relationship between V and the current motor speed is stored in a table, where V Max This indicates the maximum speed of the motor. In actual control, the initial value T of the energy recovery torque is obtained by looking up a table based on the current motor speed. Reg-Int XX represents the energy recovery torque value corresponding to the current motor speed. The specific value can be calibrated and is not specifically limited.

[0065] In step S203, based on the regenerative braking torque and motor speed, the drive motor is controlled to perform regenerative braking while the operating efficiency of the drive motor is adjusted to generate heat, and the cooling system uses the heat to heat the power battery.

[0066] It is understood that the embodiments of this application can control the working efficiency of the drive motor based on the braking energy recovery torque and the motor speed, thereby generating controllable heat while realizing braking energy recovery. Finally, the generated heat is used by the cooling system to heat the power battery, achieving efficient utilization of thermal energy. This method, by intelligently adjusting the working efficiency of the motor during braking, achieves efficient recovery of braking energy while ensuring battery safety. It also utilizes the generated waste heat to improve the low-temperature performance of the battery and reduces the load on the mechanical braking system, effectively solving problems such as low vehicle energy recovery efficiency and severe wear of the braking system in low-temperature environments.

[0067] In this embodiment, based on the regenerative braking torque and motor speed, the drive motor is controlled to perform regenerative braking while adjusting the drive motor's operating efficiency to generate heat. This includes: obtaining a pre-calibrated current lookup table of the drive motor under low-temperature thermal management conditions, wherein the drive motor's operating efficiency is lower than a preset efficiency when the current lookup table is calibrated; using the regenerative braking torque and motor speed as indexes, the current lookup table is queried to obtain the drive motor's current command; and the drive motor is controlled using the current command.

[0068] It is understood that, based on the regenerative braking torque and motor speed, the embodiments of this application can control the drive motor to perform regenerative braking while simultaneously adjusting the drive motor's operating efficiency to generate heat. First, based on a pre-calibrated current lookup table under low-temperature conditions, a current command is obtained using the regenerative braking torque and motor speed as indexes; then, the drive motor is controlled to operate according to this command, so that while performing regenerative braking, it generates the required heat by reducing its operating efficiency.

[0069] Therefore, the embodiments of this application can improve the low-temperature performance of the battery by utilizing the waste heat generated by the motor while ensuring braking performance, and at the same time reduce the use of mechanical braking, effectively solving the problems of low energy recovery efficiency and severe wear of the braking system in low-temperature environments.

[0070] Taking permanent magnet synchronous motors as an example, the control of permanent magnet synchronous motors in electric vehicles adopts a lookup table-based vector control method. This method queries the motor dq axis current command required for vector control based on the current state of the motor, and then uses vector control to make the actual dq axis current of the motor consistent with the dq axis current command, thereby ensuring that the drive motor outputs torque as expected.

[0071] Table 2 is a lookup table for the dq-axis current of the permanent magnet synchronous motor vector control provided in this application. When the motor controller receives the command from the vehicle controller to enter the low-temperature thermal management condition, it implements energy recovery control according to the allocated braking torque. This application obtains the dq-axis command of the permanent magnet synchronous motor under the current condition by querying a pre-calibrated dq-axis current table, and then implements vector control based on the current command and the actual dq-axis current of the motor to make the drive motor output the expected torque. Specifically, as shown in Table 2, Table 2 is a lookup table for the dq-axis current of the permanent magnet synchronous motor vector control.

[0072] Table 2

[0073] Table 2 shows the dq-axis current lookup table for permanent magnet synchronous motor vector control. The dq-axis current command is calibrated according to 50% of the highest efficiency, allowing the drive motor to generate more waste heat during energy recovery. This 50% can be specifically set or calibrated, such as 45% or 55%. This heat is transferred to the power battery through the electric vehicle thermal management system, heating the battery and achieving efficient thermal management under low-temperature conditions. XX represents the regenerative braking torque in the lookup table; the specific value can be calibrated and is not specifically limited.

[0074] The vehicle low-temperature thermal management control method proposed in this application first controls the vehicle to enter a low-temperature thermal management condition based on key parameters such as ambient temperature, battery module temperature, and charging capacity. Then, the vehicle's regenerative braking torque is determined based on motor speed and maximum allowable charging power. Next, by controlling the efficiency of the drive motor, controllable heat is generated while achieving regenerative braking. Finally, the generated heat is used by the cooling system to heat the power battery, achieving efficient utilization of thermal energy. This method, through intelligent adjustment of the motor's efficiency during braking, achieves efficient regeneration of braking energy while ensuring battery safety. It also utilizes the generated waste heat to improve the battery's low-temperature performance and reduces the load on the mechanical braking system, effectively solving problems such as low energy recovery efficiency and severe wear of the braking system in low-temperature environments.

[0075] The following will illustrate the implementation logic of thermal management control for electric vehicles under low-temperature conditions using a specific embodiment. Figure 3 As shown, the specific steps are as follows: In step one, the vehicle controller first determines whether the vehicle has entered the low-temperature thermal management condition based on the ambient temperature and the maximum allowable charging power output by the battery management system. If the condition is met, it proceeds to step two. If the condition is not met, it remains in step one to continue determining the condition.

[0076] In step two, the vehicle controller determines whether to enter the energy recovery state based on information such as the vehicle's gear position and brake pedal status. If the determination condition is not met, it returns directly to step one; if the determination condition is met, it proceeds to step three.

[0077] In step three, the vehicle controller calculates the energy recovery torque requirement and the braking torque allocated to the drive motor based on the current state of the vehicle.

[0078] In step four, the motor controller, based on the energy recovery torque command issued by the vehicle controller and the command to enter the low-temperature thermal management condition, controls the drive motor to output braking torque as expected by reducing the efficiency of the drive system. During this process, the extra heat generated by the reduced efficiency enters the cooling system shared by the power battery and the drive system. This application generates extra heat in the drive system by reducing efficiency, and fully utilizes the heat generated by the reduced efficiency to heat the power battery while ensuring that the drive motor outputs torque according to the command of the vehicle controller, thereby achieving efficient thermal management of the vehicle under low-temperature conditions.

[0079] In summary, the electric vehicle thermal management control method provided in this application adjusts the operating efficiency of the drive system when the charging and discharging performance of the power battery is severely degraded due to low temperatures. By reducing efficiency, the drive system generates additional heat. While ensuring that the drive motor outputs braking torque according to the vehicle controller's instructions, the heat generated by the reduced efficiency is fully utilized to heat the power battery, thereby achieving efficient thermal management of the vehicle under low-temperature conditions. The control method of this application also features clear logic, no change to the system hardware, ease of engineering implementation, and wide applicability.

[0080] Next, the vehicle low-temperature thermal management control device according to the embodiments of this application is described with reference to the accompanying drawings.

[0081] Figure 4 This is a block diagram of a vehicle low-temperature thermal management control device according to an embodiment of this application.

[0082] like Figure 4 As shown, the vehicle low-temperature thermal management control device 10 includes: an acquisition module 100, a determination module 200, and a control module 300.

[0083] The acquisition module 100 is used to acquire the ambient temperature of the vehicle, the module temperature of the power battery, and the maximum allowable charging power; the determination module 200 is used to control the vehicle to enter the low-temperature thermal management condition based on the ambient temperature, module temperature, and maximum allowable charging power, and to determine the vehicle's regenerative braking torque based on the motor speed and the maximum allowable charging power; the control module 300 is used to control the drive motor to perform regenerative braking actions based on the regenerative braking torque and motor speed, while adjusting the working efficiency of the drive motor to generate heat, and the cooling system uses the heat to heat the power battery.

[0084] In this embodiment of the application, the determining module 100 is further configured to: determine the initial value of the energy recovery torque of the drive motor based on the motor speed; determine the maximum allowable recovery torque of the power battery based on the motor speed and the maximum allowable charging power; if the initial value of the energy recovery torque is less than the maximum allowable recovery torque, then the initial value of the energy recovery torque is used as the braking energy recovery torque; if the initial value of the energy recovery torque is greater than or equal to the maximum allowable recovery torque, then the initial value of the energy recovery torque is used as the braking energy recovery torque.

[0085] In this embodiment of the application, the determining module 100 is further configured to: determine the initial value of the energy recovery torque of the drive motor based on the motor speed, including: obtaining a pre-calibrated energy recovery torque lookup table of the drive motor; using the motor speed as an index, querying the energy recovery torque lookup table to obtain the initial value of the energy recovery torque.

[0086] In this embodiment of the application, the formula for calculating the maximum permissible recovery torque is:

[0087] Among them, T Batt-Max P represents the maximum permissible regenerative torque. CHG Indicates the maximum allowable charging power, V E This indicates the motor speed.

[0088] In this embodiment of the application, the determining module 100 is further configured to: control the vehicle to enter the low temperature thermal management condition if the ambient temperature is lower than the first temperature threshold, the module temperature is lower than the second temperature threshold, and the maximum allowable charging power is lower than the power threshold.

[0089] In this embodiment of the application, a determination module is also included, which is used to obtain the current gear position, brake pedal state, accelerator pedal state and vehicle fault state of the vehicle before determining the regenerative braking torque of the vehicle based on the motor speed and the maximum allowable charging power; and to control the vehicle to enter the regenerative braking mode based on the current gear position, brake pedal state, accelerator pedal state and vehicle fault state.

[0090] In this embodiment, the control module 300 is further configured to: obtain a pre-calibrated current lookup table of the drive motor under low-temperature thermal management conditions, wherein the working efficiency of the drive motor is lower than a preset efficiency when the current lookup table is calibrated; obtain the current command of the drive motor by querying the current lookup table using the braking energy recovery torque and motor speed as indexes; and control the drive motor using the current command.

[0091] It should be noted that the foregoing explanation of the vehicle low-temperature thermal management control method embodiment also applies to the vehicle low-temperature thermal management control device of this embodiment, and will not be repeated here.

[0092] The vehicle low-temperature thermal management control device proposed in this application first controls the vehicle to enter a low-temperature thermal management state based on key parameters such as ambient temperature, battery module temperature, and charging capacity. Then, it determines the vehicle's regenerative braking torque based on motor speed and maximum allowable charging power. Next, by controlling the efficiency of the drive motor, controllable heat is generated while achieving regenerative braking. Finally, the generated heat is used by the cooling system to heat the power battery, achieving efficient utilization of thermal energy. This method, through intelligent adjustment of the motor's efficiency during braking, achieves efficient regeneration of braking energy while ensuring battery safety. It also utilizes the generated waste heat to improve the battery's low-temperature performance and reduces the load on the mechanical braking system, effectively solving problems such as low vehicle energy recovery efficiency and severe brake system wear in low-temperature environments.

[0093] Figure 5 A schematic diagram of the structure of a vehicle provided in an embodiment of this application. The vehicle may include: The memory 501, the processor 502, and the computer program stored on the memory 501 and capable of running on the processor 502.

[0094] When processor 502 executes the program, it implements the vehicle low-temperature thermal management control method provided in the above embodiments.

[0095] Furthermore, the vehicle also includes: Communication interface 503 is used for communication between memory 501 and processor 502.

[0096] The memory 501 is used to store computer programs that can run on the processor 502.

[0097] The memory 501 may include high-speed RAM (Random Access Memory) memory, and may also include non-volatile memory, such as at least one disk storage.

[0098] If the memory 501, processor 502, and communication interface 503 are implemented independently, then the communication interface 503, memory 501, and processor 502 can be interconnected via a bus to complete communication between them. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 5 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0099] Optionally, in a specific implementation, if the memory 501, processor 502, and communication interface 503 are integrated on a single chip, then the memory 501, processor 502, and communication interface 503 can communicate with each other through an internal interface.

[0100] The processor 502 may be a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of this application.

[0101] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described vehicle low-temperature thermal management control method.

[0102] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0103] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0104] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0105] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (FPGAs), field-programmable gate arrays (FPGAs), etc.

[0106] Those skilled in the art will understand that all or part of the steps of the methods implementing the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0107] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for controlling low-temperature thermal management of a vehicle, characterized in that, The vehicle includes a power battery, a drive motor, and a cooling system, wherein the power battery and the drive battery share the cooling system, and the method includes the following steps: The ambient temperature of the vehicle, the module temperature of the power battery, and the maximum allowable charging power are obtained. Based on the ambient temperature, the module temperature, and the maximum allowable charging power, the vehicle is controlled to enter a low-temperature thermal management condition, and the vehicle's regenerative braking torque is determined according to the motor speed and the maximum allowable charging power. Based on the regenerative braking torque and the motor speed, the drive motor is controlled to perform regenerative braking while the operating efficiency of the drive motor is adjusted to generate heat. The cooling system uses this heat to heat the power battery.

2. The vehicle low-temperature thermal management control method according to claim 1, characterized in that, The step of controlling the drive motor to perform brake energy recovery based on the brake energy recovery torque and the motor speed, while adjusting the drive motor's operating efficiency to generate heat, includes: Obtain a pre-calibrated current lookup table of the drive motor under the low-temperature thermal management condition, wherein the working efficiency of the drive motor is lower than the preset efficiency when the current lookup table is calibrated. Using the regenerative braking torque and the motor speed as indexes, the current command of the drive motor is obtained by querying the current lookup table; The drive motor is controlled using the current command.

3. The vehicle low-temperature thermal management control method according to claim 1, characterized in that, Determining the regenerative braking torque of the vehicle based on the motor speed and the maximum allowable charging power includes: The initial value of the energy recovery torque of the drive motor is determined based on the motor speed. The maximum allowable regenerative torque of the power battery is determined based on the motor speed and the maximum allowable charging power. If the initial value of the energy recovery torque is less than the maximum permissible recovery torque, then the initial value of the energy recovery torque is used as the braking energy recovery torque; if the initial value of the energy recovery torque is greater than or equal to the maximum permissible recovery torque, then the initial value of the energy recovery torque is used as the braking energy recovery torque.

4. The vehicle low-temperature thermal management control method according to claim 3, characterized in that, Determining the initial value of the energy recovery torque of the drive motor based on the motor speed includes: Obtain the pre-calibrated energy recovery torque lookup table of the drive motor; Using the motor speed as an index, the energy recovery torque lookup table is queried to obtain the initial value of the energy recovery torque.

5. The vehicle low-temperature thermal management control method according to claim 3, characterized in that, The formula for calculating the maximum permissible recovery torque is as follows: Among them, T Batt-Max P represents the maximum permissible regenerative torque. CHG V represents the maximum allowable charging power. E This indicates the motor speed.

6. The vehicle low-temperature thermal management control method according to claim 1, characterized in that, The step of controlling the vehicle to enter a low-temperature thermal management condition based on the ambient temperature, the module temperature, and the maximum allowable charging power includes: If the ambient temperature is lower than the first temperature threshold, the module temperature is lower than the second temperature threshold, and the maximum allowable charging power is lower than the power threshold, then the vehicle is controlled to enter the low-temperature thermal management mode.

7. The vehicle low-temperature thermal management control method according to claim 1, characterized in that, Before determining the regenerative braking torque of the vehicle based on the motor speed and the maximum permissible charging power, the method further includes: Obtain the vehicle's current gear position, brake pedal status, accelerator pedal status, and vehicle fault status; Based on the current gear position, the brake pedal status, the accelerator pedal status, and the vehicle malfunction status, the vehicle is controlled to enter the regenerative braking mode.

8. A vehicle low-temperature thermal management control device, characterized in that, The vehicle includes a power battery, a drive motor, and a cooling system, wherein the power battery and the drive battery share the cooling system, and the device includes: The acquisition module is used to acquire the ambient temperature of the vehicle, the module temperature of the power battery, and the maximum allowable charging power. The determination module is used to control the vehicle to enter a low-temperature thermal management condition based on the ambient temperature, the module temperature and the maximum allowable charging power, and to determine the vehicle's regenerative braking torque based on the motor speed and the maximum allowable charging power. The control module is used to control the drive motor to perform the braking energy recovery action based on the braking energy recovery torque and the motor speed, while adjusting the working efficiency of the drive motor to generate heat, and the cooling system uses the heat to heat the power battery.

9. A vehicle, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the vehicle low-temperature thermal management control method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed, they implement the vehicle low-temperature thermal management control method according to any one of claims 1-7.

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