Battery thermal management method and battery thermal management system

Abstract

The invention relates to the technical field of battery thermal management, in particular to a battery thermal management method and system, and the method comprises the steps: S1, collecting a battery temperature parameter, a cooling liquid temperature parameter and a vehicle working condition parameter; s2, based on the battery temperature parameter and the vehicle working condition parameter, determining that the vehicle is in a battery heating mode, a battery warm keeping mode or a battery heat dissipation mode currently; and S3, according to the determined mode, outputting a multi-loop switching instruction to establish a corresponding cooling liquid flowing path, and outputting an actuator control instruction to drive a valve body and a liquid pump to act. Mode judgment is achieved through a state machine strategy library based on the battery temperature, the cooling liquid temperature and the vehicle working condition, a hysteresis interval or retention time is set in mode switching, and an actuator response compensation control and transition loop buffering strategy is introduced, so that the cooling liquid flow in the loop switching process is continuous, and the pressure difference is controlled; and temperature lag and overshoot caused by action delay of the valve body, speed regulation inertia of the liquid pump and thermal inertia are avoided.

Description

Battery thermal management methods and battery thermal management systems Technical Field

[0001] This invention relates to the field of battery thermal management technology, specifically to battery thermal management methods and battery thermal management systems. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the safety, reliability, and full life-cycle performance of power batteries, as the core component of vehicle energy storage and output, have gradually become important indicators of vehicle technology competition. During charging and discharging, power batteries inevitably undergo electrochemical reactions and internal resistance losses, generating a certain amount of heat. The battery's temperature significantly affects its usable capacity, internal resistance characteristics, power output, and degradation rate. Especially under scenarios such as high-rate charging, prolonged high-power discharging, and extreme environmental temperatures (such as low winter temperatures or high summer temperatures), the battery temperature is prone to deviating from the optimal range, leading to performance degradation or safety risks. Therefore, achieving efficient, precise, and low-energy-consumption control of power battery temperature has become an important research direction in the field of electric and hybrid vehicles.

[0003] In existing technologies, power battery thermal management systems typically employ liquid cooling, using coolant as the heat transfer medium. Coolant circulation components (such as water pumps) drive the coolant through cold plates or battery temperature control components within the battery pack, achieving heat exchange between the battery and the coolant. The heat is then dissipated to the environment via an external heat exchanger. Typical solutions include: in high-temperature conditions with high heat dissipation demands, the coolant can exchange heat with the air conditioning cooling circuit via a front-end radiator or refrigerant heat exchanger (chiller) to improve heat dissipation capacity; in low-temperature conditions, the coolant can be heated using a PTC electric heater, heat pump system, or engine waste heat (in hybrid / plug-in hybrid vehicles) to preheat and maintain battery temperature. While these systems can meet basic battery temperature control functions, with increasing demands for range, fast charging capability, low-temperature performance, and safety in vehicles, existing technologies are increasingly revealing shortcomings in control strategies and system structure.

[0004] Firstly, existing battery thermal management control strategies often employ relatively simple threshold control or single-loop control logic, which activates or deactivates the cooling / heating function based on whether the battery temperature is above or below a certain threshold. While this control method is simple to implement, it typically lacks refined consideration of different vehicle operating conditions. For example, during charging, battery temperature control prioritizes safety over energy consumption; during driving, passenger cabin comfort and power output needs must be considered comprehensively; and during parking, system energy consumption must be minimized while maintaining safety monitoring. Existing single-threshold control strategies often struggle to switch priorities between different operating conditions, easily leading to either "over-" or "under-" control. For instance, forced cooling during parking and standby may result in wasted energy, or delayed cooling intervention during fast charging may cause the battery temperature to exceed limits.

[0005] Secondly, existing multi-loop thermal management systems generally suffer from control lag and significant temperature fluctuations in their loop switching strategies. In practical systems, valve switching exhibits a delay, pump speed regulation has inertia, and battery temperature response demonstrates significant thermal inertia. If the controller only switches loops after the battery temperature reaches a threshold, control lag often occurs, causing the battery temperature to continue rising or falling, resulting in overshoot and even overheating risks during high-temperature fast charging or high-power discharging. Furthermore, some existing control methods do not adequately consider the continuity of flow and pressure difference changes during loop switching. Valve switching may cause instantaneous interruption of coolant flow or rapid changes in local flow, leading to localized overheating or overcooling of the battery, or even vapor lock or water hammer, thus affecting heat exchange efficiency and reducing system reliability.

[0006] Secondly, existing battery thermal management systems are prone to frequent switching near the mode switching threshold. Due to measurement noise from temperature sensors and fluctuations in coolant temperature, when the battery temperature approaches the threshold, the controller may repeatedly switch between heating and heat preservation, and between heat dissipation and heat preservation, causing frequent operation of the valve body and liquid pump. This not only increases mechanical wear and reduces actuator life, but also leads to increased energy consumption, increased noise, and causes the temperature control curve to fluctuate or even exhibit a "sawtooth" shape. Although some existing technologies have introduced hysteresis control, most only target a single threshold or a fixed hysteresis range, making it difficult to dynamically adjust based on battery temperature trends, different operating conditions, and system thermal inertia, thus failing to fundamentally solve the problems of frequent switching and temperature shocks.

[0007] Furthermore, insufficient waste heat recovery and utilization in existing technologies leads to high energy consumption for low-temperature heating. Especially in pure electric vehicles, battery preheating in low-temperature environments typically relies on PTC electric heating or heat pump systems. PTC heating is inefficient and consumes a lot of power, directly reducing driving range. While heat pump systems are more efficient, their complex structure and reduced heating capacity at extremely low temperatures are significant issues. In hybrid or plug-in hybrid vehicles, waste heat generated by the electric drive, electronic control, or engine has some recovery value, but existing control strategies often fail to prioritize waste heat for battery heating or lack compensation mechanisms for insufficient waste heat, resulting in wasted waste heat resources or insufficient battery warm-up, affecting low-temperature charging capacity and power output performance. Existing technologies lack adaptability to differences in heat exchanger efficiency and hardware aging. Components in the battery thermal management system, such as heat exchangers, liquid pumps, and valves, exhibit performance differences across different batches, suppliers, or assembly conditions. Simultaneously, during long-term operation, heat exchangers may experience scaling and blockage, liquid pump impeller wear leading to flow rate reduction, and decreased valve sealing performance causing bypass leakage, all of which gradually reduce the system's heat exchange capacity. Traditional control strategies are mostly based on fixed model parameters or empirical thresholds during the calibration phase, lacking online identification and adaptive update capabilities. When hardware performance deviates, the system is prone to insufficient or excessive temperature control, which in turn affects battery safety and energy consumption. Especially in high-temperature fast charging scenarios, reduced heat exchange capacity may lead to ineffective temperature control, thereby limiting charging power or even causing safety hazards.

[0008] Furthermore, existing temperature control strategies have safety blind spots when the vehicle is charging and in a powered-off or standby state. Some models reduce the controller's operating frequency or stop the thermal management actuator from working after the vehicle is powered off, resulting in the battery temperature relying solely on natural heat dissipation during charging, which is insufficient to cope with the large amount of heat generated by fast charging. If the ambient temperature is high, heat dissipation conditions are poor, or heat exchanger efficiency decreases, the battery temperature may continue to rise and exceed the safety threshold. Simultaneously, when sensors or actuators malfunction, existing technologies often lack robust safety degradation strategies, such as the inability to switch to a conservative heat dissipation circuit in a timely manner, or the inability to limit the rate of temperature rise or the upper temperature limit, leading to battery temperature control failure in fault conditions and posing certain safety risks.

[0009] In summary, while existing battery thermal management systems can achieve basic heating and cooling functions, they still generally suffer from the following key technical problems: The control strategy lacks refined adaptation to various operating conditions such as charging, driving, and parking, making it difficult to achieve optimal control that balances energy consumption and safety; the multi-loop switching process suffers from actuator response lag, discontinuous flow, and thermal inertia, easily leading to temperature overshoot or localized temperature anomalies; frequent switching near the mode critical point easily results in increased energy consumption, reduced actuator lifespan, and increased temperature fluctuations; insufficient waste heat recovery and utilization, high energy consumption for low-temperature heating, and potentially insufficient heating rate; lack of online heat exchange efficiency estimation and adaptive calibration capabilities, making it difficult to cope with individual differences in heat exchangers and performance degradation caused by hardware aging; and insufficient temperature control and fault degradation strategies during the charging standby phase, posing a risk of temperature runaway.

[0010] Therefore, there is an urgent need to propose battery thermal management methods and systems to solve the aforementioned problems in existing technologies and improve the temperature control performance and safety reliability of power batteries. Summary of the Invention

[0011] To address the problems in the prior art, this invention provides a battery thermal management method and a battery thermal management system.

[0012] The technical solution adopted by this invention to solve its technical problem is: a battery thermal management method applied to a battery thermal management system, the system including at least a battery temperature control component, a coolant circulation component, a refrigerant heat exchange component, a waste heat recovery heat exchange component, and a switchable multi-loop pipeline, including:

[0013] S1. Collect battery temperature parameters, coolant temperature parameters, and vehicle operating parameters;

[0014] S2. Based on the battery temperature parameters and vehicle operating parameters, determine whether the current mode is battery heating mode, battery temperature preservation mode, or battery heat dissipation mode.

[0015] S3. Based on the determined mode, output multi-loop switching command to establish the corresponding coolant flow path, and output actuator control command to drive the valve body and liquid pump to operate.

[0016] S4. In battery heating mode, control the waste heat recovery heat exchange component to supply heat to the coolant to increase the battery temperature.

[0017] S5. In battery heat dissipation mode, control the refrigerant heat exchange component to conduct heat outward to reduce battery temperature;

[0018] S6. Dynamically adjust the multi-loop switching command according to the battery temperature change trend to maintain the battery temperature within the target operating range.

[0019] The beneficial effects of this invention are:

[0020] (1) The battery thermal management method and battery thermal management system described in this invention determine the mode based on the state machine / strategy library of battery temperature, coolant temperature and vehicle operating conditions, and set a hysteresis interval or holding time during mode switching. At the same time, it introduces actuator response compensation control and transition loop buffer strategy to make the coolant flow continuous and the pressure difference controlled during the loop switching process, avoiding temperature lag and overshoot caused by valve body action delay, pump speed regulation inertia and thermal inertia; and dynamically adjusts the loop command based on the battery temperature change trend to keep the battery temperature within the target operating range. Therefore, compared with the problems of large temperature fluctuation, frequent critical point switching and temperature shock during switching caused by simple threshold control or fixed loop control in the prior art, this invention can achieve a smoother, more stable and faster temperature control effect, thereby improving battery safety, comfort and actuator life.

[0021] (2) The battery thermal management method and battery thermal management system described in this invention prioritize the use of waste heat recovery heat exchange components to heat the battery in heating mode, and only activate auxiliary heating components when waste heat is insufficient, thereby reducing the use of high-power electric heating; in heat dissipation mode, the refrigerant heat exchange components and at least two heat exchange units operate in coordination, and the proportion of each heat exchange unit is dynamically adjusted according to the temperature drop rate to improve the utilization rate of cooling capacity and reduce energy redundancy; at the same time, the heat exchange efficiency parameters are estimated online and the loop control parameters are calibrated, and the threshold and control parameters are adaptively updated based on the control error trend or the liquid pump flow decay trend to compensate for the decrease in heat exchange capacity caused by individual differences of heat exchangers and hardware aging. In addition, the temperature control closed loop is maintained during charging and when the vehicle is off or in standby mode, and a safety degradation strategy is provided when the sensor / actuator is abnormal, so that the system can still operate reliably in high-risk scenarios such as fast charging, high temperature, and standby. Therefore, compared with the problems of insufficient waste heat utilization, high energy consumption, inconsistent control effect due to heat exchange capacity deviation and lack of standby charging temperature control that are common in existing technologies, this invention can reduce energy consumption, improve battery life, and enhance consistency throughout the entire life cycle and safety and reliability under extreme working conditions. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 is a general flowchart of the battery thermal management method and battery thermal management system provided by the present invention.

[0024] Figure 2 is a flowchart of the pattern determination and strategy library / state machine provided by the present invention;

[0025] Figure 3 is a detailed flowchart of the heating mode provided by the present invention;

[0026] Figure 4 is a detailed flowchart of the heat dissipation mode provided by the present invention;

[0027] Figure 5 is a flowchart of the actuator response compensation and switching sequence provided by the present invention;

[0028] Figure 6 is a flowchart of the online heat exchange efficiency estimation and parameter calibration provided by the present invention;

[0029] Figure 7 is a flowchart of the adaptive update and aging compensation process provided by the present invention. Detailed Implementation

[0030] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0031] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] As shown in Figures 1-7, a battery thermal management control method of the present invention is applied to a battery thermal management system. The system includes at least a battery temperature control component, a coolant circulation component, a refrigerant heat exchange component, a waste heat recovery heat exchange component, and a switchable multi-loop pipeline, including:

[0034] S1. Collect battery temperature parameters, coolant temperature parameters, and vehicle operating parameters;

[0035] S2. Based on battery temperature parameters and vehicle operating parameters, determine whether the current mode is battery heating mode, battery temperature preservation mode, or battery heat dissipation mode.

[0036] S3. Based on the determined mode, output multi-loop switching command to establish the corresponding coolant flow path, and output actuator control command to drive the valve body and liquid pump to operate.

[0037] S4. In battery heating mode, control the waste heat recovery heat exchange component to supply heat to the coolant to increase the battery temperature.

[0038] S5. In battery heat dissipation mode, control the refrigerant heat exchange component to conduct heat outward to reduce battery temperature;

[0039] S6. Dynamically adjust the multi-circuit switching command according to the battery temperature change trend to keep the battery temperature within the target operating range.

[0040] The controller first acquires battery temperature parameters, coolant temperature parameters, and vehicle operating condition parameters. Based on the battery temperature parameters and considering different vehicle operating conditions such as charging, driving, or parking, the controller determines the current thermal management requirements and then decides whether the system should be in battery heating mode, battery temperature maintenance mode, or battery cooling mode. Subsequently, the controller outputs multi-loop switching commands according to the determined mode, enabling the switchable multi-loop pipelines to establish corresponding coolant flow paths. Simultaneously, it outputs actuator control commands to drive valve body movements and adjust the operation of the liquid pump, ensuring the coolant circulates according to the target loop. When entering battery heating mode, the waste heat recovery heat exchange component transfers usable waste heat to the coolant, which then exchanges heat with the battery temperature control component to raise the battery temperature. When entering battery cooling mode, the refrigerant heat exchange component dissipates the heat carried by the coolant to the external environment, thereby lowering the battery temperature. At the same time, the controller adjusts the loop switching commands and liquid pump control in real time according to the battery temperature change trend, ensuring the battery temperature is continuously maintained within the target operating range.

[0041] By employing the aforementioned control method, battery thermal management can automatically match the most suitable thermal management mode based on the battery temperature under different operating conditions. It also flexibly alters the coolant flow path through multi-loop switching, thereby achieving unified control over battery heating, heat preservation, and cooling. Since the heating process prioritizes waste heat recovery heat exchange components rather than directly using high-power electric heating, energy consumption is significantly reduced and the vehicle's range is improved. During the heat dissipation process, efficient heat removal through refrigerant heat exchange components allows the battery temperature to quickly drop back to a safe range, further enhancing battery safety and lifespan. Simultaneously, the dynamic adjustment strategy based on temperature trends effectively suppresses temperature overshoot and hysteresis, improving temperature control accuracy and reducing frequent actuator operations.

[0042] The battery thermal management system includes a battery temperature control component, a liquid pump, a three-way valve, a refrigerant heat exchange component, and a waste heat recovery heat exchange component, and features switchable multi-loop piping. Taking the target battery operating range of 20℃~35℃ as an example: when the battery temperature is below 15℃ and the vehicle is in driving or charging mode, the controller determines to enter the battery heating mode, controls the valve body to switch to the waste heat recovery heat exchange loop, and the liquid pump operates at 60% of its rated speed, allowing the coolant to absorb waste heat through the waste heat recovery heat exchange component and flow through the battery temperature control component to heat the battery; when the battery temperature is above 38℃, the controller determines to enter the battery cooling mode, controls the valve body to switch to the refrigerant heat exchange loop and increases the liquid pump speed to 80%, allowing the heat carried by the coolant to be released to the environment at the refrigerant heat exchange component; when the battery temperature is between 18℃ and 37℃, the controller enters the temperature maintenance mode, maintaining a stable temperature through a bypass loop and low pump speed circulation to avoid energy waste.

[0043] When the vehicle is not ready, press and hold the energy recovery level button for 10 seconds to enter the full-speed commissioning mode. Once the vehicle is ready or the power is completely off, the water pump will exit the full-speed commissioning mode.

[0044] Its purpose is to facilitate the addition of air to the thermal management water system during market maintenance. This function helps to perform multiple filling and venting operations of the thermal management medium when not mechanically filled (vacuum filling). Additionally, it is suitable for customers in Northeast China to perform forced starts on vehicles that are not yet ready for maintenance.

[0045] During a cold start in winter, the vehicle is started after being left idle overnight. S1 detects a battery temperature of -5℃ and a coolant temperature of 0℃, indicating the vehicle is in driving mode. S2 determines this to be "battery heating mode." S3 instructs the cooling circuit to close, opens the valve connecting the motor / electronic control waste heat recovery unit, and starts the liquid pump. S4 guides the low-temperature coolant through the high-temperature motor / electronic control radiator to absorb waste heat; the warmed coolant then flows into the battery pack to heat it.

[0046] During summer fast charging, the vehicle is connected to a DC fast charging station. S1 detects a battery temperature of 35°C with a continuously rising trend, indicating the vehicle is in "charging mode." S2 determines the mode to be "battery cooling mode." S3 instructs a pipeline switch to connect the battery pack to the refrigerant heat exchange components and starts the air conditioning compressor. S5 guides the high-temperature coolant to exchange heat with the low-temperature refrigerant in the chiller, cooling it before returning it to the battery pack to further cool it. S6 dynamically adjusts the air conditioning compressor power and coolant pump speed based on the temperature drop rate.

[0047] As a preferred technical solution, the current mode includes:

[0048] Input the battery temperature parameters, coolant temperature parameters, and vehicle operating condition parameters into the thermal management state machine or strategy library to obtain the target thermal management mode and its corresponding loop combination scheme. The vehicle operating condition parameters include at least one of the following: charging condition, driving condition, and parking condition.

[0049] The controller inputs battery temperature parameters, coolant temperature parameters, and vehicle operating condition parameters into a state machine or strategy library. The state machine outputs a target thermal management mode based on a preset rule set, threshold range, and operating condition priority logic, and generates a loop combination scheme corresponding to that mode. Since vehicle operating conditions include at least one of charging, driving, and parking conditions, the state machine can differentiate the mode selection according to the control priority under different conditions. For example, under charging conditions, where temperature safety requirements are higher, a stronger heat dissipation strategy is prioritized; while under parking conditions, energy saving can be prioritized to avoid long-term high-load operation of actuators.

[0050] By delegating mode determination to a state machine or strategy library, the thermal management control logic becomes configurable, iterative, and interpretable, facilitating adjustments to thresholds and loop combinations based on vehicle platform characteristics during mass production calibration. Simultaneously, the strategy library can employ differentiated control for different operating conditions, avoiding energy waste caused by excessive heat dissipation or heating in certain low-priority scenarios and improving overall vehicle efficiency. When the vehicle is charging, if the battery temperature exceeds 40°C, it is forced into cooling mode and refrigerant heat exchange is activated; if the battery temperature is below 10°C, it enters heating mode and prioritizes waste heat recovery. When the vehicle is driving, if the battery temperature is only slightly above the target upper limit, a low-intensity cooling loop is prioritized to reduce noise and energy consumption. When the vehicle is parked, unless the temperature exceeds the safety upper limit threshold, it maintains a temperature-maintaining mode and reduces pump speed to ensure low-power operation.

[0051] As a preferred technical solution, the loop control is dynamically adjusted based on the thermal management objective function, which includes at least two of the following objectives:

[0052] Reduce energy consumption, minimize temperature fluctuations, shorten heating or cooling time, reduce actuator switching frequency, and improve waste heat utilization.

[0053] The objective function should include at least two of the following: reducing energy consumption, minimizing temperature fluctuations, shortening heating or cooling time, reducing actuator switching frequency, and improving waste heat utilization. The controller evaluates different loop combinations and actuator control variables, selects the control strategy that optimizes the objective function value, and controls valve switching, pump speed, and heat exchange component operation accordingly. Using a thermal management objective function for loop control avoids performance deviations caused by single-indicator control. For example, solely pursuing rapid cooling may lead to prolonged high-load compressor operation, resulting in increased energy consumption; conversely, solely pursuing low energy consumption may lead to excessive battery temperature fluctuations. Multi-objective optimization can balance factors such as temperature stability, energy consumption, and actuator lifespan, resulting in better overall thermal management performance.

[0054] The controller employs a weighted objective function for strategy selection, with energy consumption weighted at 0.4, temperature deviation weighted at 0.3, switching frequency weighted at 0.2, and waste heat utilization rate weighted at 0.1. When the battery temperature approaches the target upper limit, the strategy library prioritizes partial refrigerant heat exchange and pump speed fine-tuning schemes, rather than directly switching to the forced cooling loop. This approach reduces energy consumption and valve actuation frequency while ensuring temperature compliance.

[0055] As a preferred technical solution, the state machine or strategy library sets a hysteresis interval or hold time for mode switching so that frequent switching is not triggered when the battery temperature fluctuates near the mode critical point.

[0056] When the battery temperature fluctuates near the mode critical point, the controller will not immediately trigger mode switching. Instead, it will require the temperature to exceed the critical threshold and remain there for a period of time before switching, or it will use different hysteresis intervals for the upper and lower thresholds to maintain the mode, thereby avoiding frequent switching caused by temperature noise or short-term fluctuations.

[0057] By introducing a hysteresis interval or hold time, mechanical wear and energy loss caused by frequent switching between the valve body and the pump can be significantly reduced, and temperature control stability can be improved. System stability is particularly enhanced when the battery temperature is near the threshold, preventing discontinuous temperature changes caused by mode jitter. The threshold for exiting heating mode is set at 22°C, while the threshold for re-entering heating mode is set at 18°C, forming a 4°C hysteresis interval. Simultaneously, a minimum 30-second hold time is allowed after mode switching before allowing another switch. When the battery temperature fluctuates around 20°C, the controller maintains the current mode, preventing frequent valve body movements.

[0058] As a preferred technical solution, the output multi-loop switching command includes actuator response compensation control:

[0059] Based on the valve body action delay, the pump speed regulation inertia, and the battery temperature change trend, the valve body switching command is issued in advance and / or the pump speed is adjusted in advance before the circuit switching, so as to reduce the temperature control lag.

[0060] Based on valve action delay, pump speed inertia, and battery temperature change trends, the controller issues valve switching commands and / or adjusts pump speed in advance before loop switching, allowing the target loop to gradually build up heat exchange capacity before the temperature reaches the threshold, thereby reducing control lag. Since both the valve and pump have a certain response delay, traditional strategies often only execute switching after the temperature has already exceeded the threshold, easily leading to overshoot. This solution uses predictive compensation to intervene in heat exchange earlier, thereby reducing temperature overshoot and shortening settling time, improving the real-time performance and safety margin of battery temperature control.

[0061] The average valve body action time is 0.8 seconds, and the pump speed response time is 2 seconds. If the controller detects that the battery temperature rise rate exceeds 0.2℃ / s and predicts that it will exceed the upper limit threshold within 30 seconds, it will switch the valve body 1 second in advance and increase the pump speed to 70% of the target value 2 seconds in advance to establish the heat dissipation circuit in advance and avoid temperature exceeding the limit.

[0062] As a preferred technical solution, actuator response compensation control includes:

[0063] The valve body and liquid pump are controlled sequentially according to the preset switching sequence, so that the coolant flow rate is continuous or the pressure difference change is controlled during the circuit switching process, so as to avoid local overheating, local overcooling or vapor lock of the battery.

[0064] The actuator response compensation control includes preset switching sequence control, which controls the valve body and liquid pump to operate sequentially, ensuring continuous coolant flow or controlled differential pressure changes during loop switching. By first adjusting the liquid pump to create a transition flow, then executing the valve body switching, and finally adjusting the pump speed to the target value, flow interruption or sudden changes in local flow can be avoided during heat exchange, thereby suppressing local overheating, local undercooling, or vapor lock phenomena.

[0065] This solution ensures a smoother circuit switching process, avoiding sudden increases in local battery temperature due to flow interruptions or localized overcooling due to instantaneous high flow rates. It also reduces the risk of vapor lock, improves system reliability and repeatability, and is particularly suitable for complex multi-loop cooling systems.

[0066] When switching from the heat preservation mode to the heat dissipation mode, the controller first increases the pump speed from 30% to 50% to establish a transition flow, then opens the bypass valve to form a parallel transition loop, then closes the original loop valve and opens the refrigerant heat exchange loop valve, and finally increases the pump speed to 80% and starts the refrigerant heat exchange components to achieve continuous and stable switching.

[0067] As a preferred technical solution, the multi-loop switching command includes: when switching from the first mode to the second mode, first establishing a transition loop for short-term heat exchange buffering, and then switching to the target loop combination to suppress overshoot caused by temperature shock or thermal inertia.

[0068] When the system switches from the first mode to the second mode, the controller first establishes a transition loop to provide short-term heat exchange buffering for the coolant before switching to the target loop combination. The transition loop can be implemented through bypass mixing, partial heat exchange, or parallel heat exchange, allowing thermal inertia to be released gradually and avoiding temperature shocks caused by forced heat exchange. By setting a transition loop, temperature shocks and overshoot can be significantly suppressed, making the battery temperature change curve smoother, improving control stability, and reducing large load changes in actuators caused by sudden switching, thereby improving component lifespan. When switching from the temperature holding mode to the heat dissipation mode, the controller first enters the transition loop for 10 seconds: part of the coolant enters the refrigerant heat exchanger, and the other part flows back through the bypass loop, reducing the heat exchange intensity through mixing; after the temperature drop rate tends to stabilize, it switches to the full refrigerant heat exchange loop, thereby avoiding overcooling or overshoot caused by rapid temperature drop.

[0069] As a preferred technical solution, the heat exchange efficiency parameters are estimated online based on the battery temperature response curve and coolant temperature change, and the loop control parameters are calibrated according to the heat exchange efficiency parameters to adapt to the efficiency deviations of different batches or individual heat exchangers.

[0070] The controller estimates heat transfer efficiency parameters, such as the heat transfer coefficient or equivalent UA value, online based on the battery temperature response curve and coolant temperature changes. Through dynamic identification of the actual heat transfer effect of the heat exchanger, the controller can identify performance differences between different batches or individual heat exchangers and calibrate loop control parameters based on the heat transfer efficiency parameters, including pump speed mapping, valve opening control, or mode switching threshold adjustment. Online heat transfer efficiency estimation and calibration make the system more robust to hardware differences, ensuring consistent temperature control even when the same control strategy is applied to different vehicles or individual heat exchangers. Simultaneously, the controller automatically compensates for heat transfer performance degradation over time, avoiding safety risks caused by decreased temperature control capabilities and reducing maintenance requirements. The controller uses a recursive least squares algorithm to identify the heat transfer efficiency UA value online. If the identification result shows that UA has decreased by 10% compared to the initial value, the target pump speed is automatically increased by 5%, and the cooling mode entry threshold is lowered by 1°C, ensuring the system still achieves the expected cooling effect under the same operating conditions.

[0071] As a preferred technical solution, calibration includes:

[0072] The effective heat dissipation capacity of the refrigerant heat exchange components is modified according to the ambient temperature or the working status of the condenser, and the pump speed, valve opening or circuit combination is adjusted accordingly to maintain the target cooling effect.

[0073] When the ambient temperature is high or the condenser's heat dissipation capacity is insufficient, the actual cooling capacity of the refrigerant heat exchange components decreases. The controller then increases the coolant flow and heat exchange by increasing the liquid pump speed, widening the valve opening, or adjusting the circuit combination, thereby maintaining the target cooling effect. This correction mechanism allows the thermal management system to adapt to fluctuations in heat dissipation capacity caused by high-temperature environments, low wind speeds, or condenser contamination, avoiding situations where the controller's commands are effective but the actual cooling is ineffective. This improves the reliability of battery heat dissipation in extreme high-temperature scenarios and prevents excessive compressor operation from wasting energy. When the ambient temperature exceeds 35°C and the condenser fan is detected running at low speed, the controller sets the refrigerant heat exchange capacity correction factor to 0.8, increases the liquid pump speed by 15%, increases the valve opening to 90%, and coordinates the front-end fan speed increase to ensure that the battery temperature can still drop from 45°C to 35°C.

[0074] As a preferred technical solution, based on the trend of temperature control error change and

[0075] Based on the changing trend of the liquid pump flow rate decay characteristics

[0076] Adaptive updates are made to the liquid pump control parameters, loop switching rules, or state machine thresholds to compensate for the decrease in heat exchange capacity caused by hardware aging.

[0077] The controller adaptively updates the pump control parameters, loop switching rules, or state machine thresholds based on the changing trends of temperature control error and / or pump flow rate attenuation characteristics. When it detects a decrease in the actual flow rate of the pump at the same commanded speed, or a continuous increase in temperature control error, the controller determines that the heat exchange capacity has decreased and compensates for the impact of hardware aging by increasing the pump speed, switching to a stronger heat exchange loop earlier, or adjusting the threshold. This adaptive update can maintain thermal management performance under hardware aging conditions, avoiding uncontrollable battery temperature due to pump wear, pipeline blockage, or decreased heat exchanger efficiency, thereby improving the safety and reliability of the entire vehicle's life cycle and reducing after-sales risks caused by heat exchange capacity attenuation. After long-term system operation, if a 15% decrease in pump flow rate is detected, the controller increases the overall pump speed mapping table by 10% to ensure the same target flow rate; at the same time, it lowers the cooling mode entry threshold from 38°C to 37°C, allowing the system to intervene in cooling earlier and compensate for the impact of decreased heat exchange capacity.

[0078] As a preferred technical solution, in battery heating mode:

[0079] The waste heat recovery heat exchange component is activated first to heat the battery, and the auxiliary heating component is activated when the waste heat is insufficient to meet the temperature rise requirements.

[0080] Whether to activate the auxiliary heating component is determined based on the judgment result of insufficient heating rate or the expected time to reach the target temperature exceeding the limit value.

[0081] In battery heating mode, the controller prioritizes activating the waste heat recovery heat exchange component to transfer waste heat generated by the electric drive or engine systems to the coolant to heat the battery. When the waste heat is insufficient to meet the heating requirements, the controller further activates the auxiliary heating component. Whether to activate auxiliary heating is determined by the result of insufficient heating rate or the expected time to reach the target temperature exceeding the limit value. In other words, the controller predicts the battery temperature rise trend and supplements auxiliary heating power when the target temperature cannot be reached on time. By prioritizing waste heat heating and activating auxiliary heating as needed, the energy consumption of electric heating can be significantly reduced, improving low-temperature range performance. Furthermore, it can ensure rapid battery heating in extremely cold or insufficient waste heat scenarios, reducing power limitation caused by increased internal resistance at low temperatures, and improving overall vehicle power performance and charging performance. The battery needs to provide approximately 3.5 kWh of heat to heat from -10°C to 15°C, and the waste heat recovery heat exchange component can provide approximately 2 kW of thermal power. If the controller calculates that the heating time relying solely on waste heat would exceed 30 minutes, it will activate 1.5 kW of PTC auxiliary heating, shortening the heating time to approximately 20 minutes to achieve the predetermined heating target.

[0082] After a scheduled charging session in winter, the vehicle begins intelligent preheating two hours before departure. Initially, the system attempts to heat the onboard PTC and battery using only grid power, which consumes significant energy. After optimization, the system first attempts to preheat using waste heat generated by the battery management unit during charging, 30 minutes before departure. If calculations show that waste heat alone is insufficient to reach the target temperature before departure, the PTC is automatically activated 15 minutes before departure for auxiliary heating, ensuring the battery is at its optimal temperature when the user departs, while minimizing total energy consumption.

[0083] As a preferred technical solution, in the battery heat dissipation mode: at least two heat exchange units are controlled to operate in coordination according to the current heat dissipation requirements, and the operating ratio of each heat exchange unit is dynamically adjusted according to the temperature drop rate, so as to improve the utilization rate of cooling capacity and reduce energy redundancy.

[0084] In battery cooling mode, the controller coordinates the operation of at least two heat exchange units according to the current cooling demand, and dynamically adjusts the operating ratio of each heat exchange unit according to the rate of temperature drop. Specifically, when the cooling demand is high, the controller simultaneously increases the workload of the refrigerant heat exchange components and other cooling units; when the temperature approaches the target range, the controller reduces the proportion of high-energy-consuming heat exchange units and uses low-energy-consuming cooling units to maintain temperature stability, thereby maximizing the utilization rate of cooling capacity.

[0085] This collaborative control strategy avoids excessive heat dissipation capacity leading to energy redundancy, reduces the operating time of high-power devices such as compressors, and makes the temperature curve smoother by dynamically adjusting the proportion, reducing thermal shock caused by sudden cooling, improving battery temperature control quality and saving energy.

[0086] When the battery temperature is above 45℃, the controller sets the refrigerant heat exchange component ratio to 70% and the radiator ratio to 30% to cool down quickly. When the battery temperature drops to 38℃, the refrigerant heat exchange component ratio is reduced to 30% and the radiator ratio is increased to 70%. When the temperature drops to around 35℃, the refrigerant heat exchange component is turned off, and only the radiator + low pump speed circulation is maintained to achieve energy saving and noise reduction.

[0087] As a preferred technical solution, when the vehicle is charging and the vehicle is powered off or in standby mode:

[0088] The battery temperature acquisition and mode determination are still maintained, and the liquid pump, valve body and heat exchange components are controlled.

[0089] When a sensor or actuator malfunction is detected, switch to a preset safety degradation strategy to limit the rate of battery temperature rise or limit the upper limit of battery temperature.

[0090] While the vehicle is charging and powered off or in standby mode, the controller continues to collect battery temperature data and determine the charging mode, and continues to control the liquid pump, valve body, and heat exchange components to prevent abnormal battery temperature rise during charging. Simultaneously, when a sensor or actuator malfunction is detected, the controller switches to a preset safety degradation strategy to ensure safety by limiting the rate of temperature rise or limiting the upper temperature limit. For example, safety protection can be achieved by using conservative thresholds for early heat dissipation, limiting charging power, or forcibly opening the cooling circuit. By maintaining closed-loop temperature control even during the charging standby phase, this solution significantly improves charging safety, avoiding the risk of overheating or thermal runaway due to heat accumulation when the vehicle is stationary during charging. Furthermore, the safety degradation strategy ensures that temperature rise can still be controlled in the event of sensor or actuator failure, meeting vehicle safety regulations and battery management system safety requirements, and reducing the risk of accidents.

[0091] When the vehicle is fast charging and powered off, the controller still collects the battery temperature and determines the mode every 1 second. If the temperature exceeds 40°C, it forces heat dissipation and turns on the refrigerant heat exchange component. If the temperature sensor fails, it uses a backup estimated temperature and enters a conservative heat dissipation strategy, with the liquid pump running at 80% speed and the radiator turned on. If the liquid pump fails, the controller reduces the charging current and alarms to prevent the temperature from continuing to rise.

[0092] When the vehicle is charging at a DC fast charging station, the driver locks the car and leaves, putting the vehicle into a low-power standby mode. However, an independent monitoring unit of the battery thermal management system continues to operate, constantly monitoring the battery temperature. Once the temperature exceeds a safety threshold, this unit will automatically wake up the relevant controllers and start the coolant circulation pump and cooling fan to cool the battery. If the coolant temperature sensor suddenly reports a fault value at this time, the system immediately triggers a safety degradation strategy: sending a request to the charging station to limit the charging power to reduce heat generation; forcing the cooling fan and coolant pump to continue operating in a safe mode (medium speed); and sending an alarm to the user's mobile app.

[0093] A battery thermal management system includes a data acquisition module for acquiring battery temperature parameters, coolant temperature parameters, and vehicle operating parameters.

[0094] The decision module is used to determine the battery heating mode, battery temperature preservation mode, or battery heat dissipation mode based on parameters, and to generate a circuit switching strategy.

[0095] The execution control module is used to output control commands to the valve body and liquid pump to switch the coolant flow loop and drive the heat exchange components to work.

[0096] The system comprises a data acquisition module, a decision-making module, and an execution control module. The data acquisition module acquires battery temperature parameters, coolant temperature parameters, and vehicle operating condition parameters. The decision-making module determines the battery heating mode, battery temperature maintenance mode, or battery heat dissipation mode based on these parameters and generates a loop switching strategy. The execution control module outputs control commands to the valve body and liquid pump to switch the coolant flow loop and drive the heat exchange components. The system employs a modular structure for thermal management control, ensuring a clear hardware and software implementation path and facilitating vehicle platform integration and functional expansion. The separation of data acquisition, decision-making, and execution improves system reliability and diagnostic capabilities, better supporting the control requirements of complex multi-loop piping structures. Simultaneously, the multi-mode control strategy implemented through the decision-making module reduces energy consumption and improves temperature control performance, enhancing the system's engineering applicability. The data acquisition module includes multiple temperature sensors and operating condition acquisition interfaces. The decision-making module is deployed within the BMS or VCU controller, and the execution control module sends commands to the liquid pump controller and valve body controller via the CAN bus. The decision-making module runs on a 100ms cycle and outputs the loop combination scheme in real time; the execution control module executes valve opening and closing control and liquid pump speed control on a 50ms cycle, enabling the system to automatically switch between heating, heat preservation and heat dissipation modes.

[0097] An electronic device includes a processor, a memory, and a computer program stored in the memory.

[0098] By embedding the control logic into a software program and running it on the vehicle controller, automatic battery temperature acquisition, mode determination, loop switching, and actuator control can be achieved. This invention utilizes electronic devices or storage media to implement the method, enabling thermal management control to be deployed and upgraded via software. It is easily reused across different vehicle platforms and supports OTA updates, thereby reducing development and mass production costs. Furthermore, integrating this system into a vehicle allows for safe battery temperature control under various operating conditions, improving overall vehicle safety, reliability, and range. The processor is an automotive-grade MCU or SoC, and the memory is automotive-grade Flash or eMMC. The program executes the thermal management strategy in a periodic task manner. Whether the vehicle is driving, charging, or parked, the control program continuously runs and communicates with the liquid pump, valve body, and heat exchange component controllers via CAN to complete loop switching and heat exchange regulation, thereby achieving the battery temperature control target.

[0099] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. 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.

[0100] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A battery thermal management control method, applied to a battery thermal management system, said system comprising at least a battery temperature control component, a coolant circulation component, a refrigerant heat exchange component, a waste heat recovery heat exchange component, and a switchable multi-loop pipeline, characterized in that, include: S1. Collect battery temperature parameters, coolant temperature parameters, and vehicle operating parameters; S2. Based on the battery temperature parameters and vehicle operating parameters, determine whether the current mode is battery heating, battery temperature maintenance, or battery cooling. S3. According to the determined mode, output a multi-loop switching command to establish the corresponding coolant flow path, and output actuator control commands to drive the valve body and pump. S4. In battery heating mode, control the waste heat recovery heat exchange component to supply heat to the coolant to increase the battery temperature. S5. In battery cooling mode, control the refrigerant heat exchange component to conduct heat outwards to reduce the battery temperature. S6. Dynamically adjust the multi-loop switching command according to the battery temperature change trend to maintain the battery temperature within the target operating range.

2. The battery thermal management control method according to claim 1, characterized in that: The process of determining the current mode includes: inputting battery temperature parameters, coolant temperature parameters, and vehicle operating condition parameters into the thermal management state machine or strategy library to obtain the target thermal management mode and its corresponding loop combination scheme, wherein the vehicle operating condition parameters include at least one of charging condition, driving condition, and parking condition.

3. The battery thermal management system according to claim 2, characterized in that: The dynamic adjustment is based on the thermal management objective function for loop control. The thermal management objective function includes at least two of the following objectives: reducing energy consumption, reducing temperature fluctuations, shortening heating or cooling time, reducing actuator switching frequency, and improving waste heat utilization.

4. The battery thermal management control method according to any one of claims 1-3, characterized in that: The state machine or strategy library sets a hysteresis interval or hold time for mode switching so that frequent switching is not triggered when the battery temperature fluctuates near the mode critical point.

5. The battery thermal management control method according to any one of claims 1-4, characterized in that: The output multi-loop switching command includes actuator response compensation control: based on valve body action delay, pump speed regulation inertia and battery temperature change trend, the valve body switching command is issued in advance and / or the pump speed is adjusted in advance before the loop switching to reduce temperature control lag.

6. The battery thermal management control method according to claim 5, characterized in that: The actuator response compensation control includes: controlling the valve body and liquid pump to operate sequentially according to a preset switching sequence, so that the coolant flow rate is continuous or the pressure difference change is controlled during the circuit switching process, so as to avoid local overheating, local overcooling or vapor lock of the battery.

7. The battery thermal management control method according to claim 6, characterized in that: The multi-loop switching command includes: when switching from the first mode to the second mode, first establishing a transition loop for short-term heat exchange buffering, and then switching to the target loop combination to suppress overshoot caused by temperature shock or thermal inertia.

8. The battery thermal management control method according to any one of claims 1-7, characterized in that: Based on the battery temperature response curve and coolant temperature change, the heat exchange efficiency parameters are estimated online, and the loop control parameters are calibrated according to the heat exchange efficiency parameters to adapt to the efficiency deviations of different batches or individual heat exchangers.

9. The battery thermal management control method according to claim 8, characterized in that: The calibration includes: correcting the effective heat dissipation capacity of the refrigerant heat exchange components based on the ambient temperature or the condenser's operating status, and adjusting the pump speed, valve opening, or circuit combination accordingly to maintain the target cooling effect.

10. The battery thermal management control method according to claim 6, characterized in that: Based on the changing trend of temperature control error and / or the changing trend of liquid pump flow rate decay characteristics, the liquid pump control parameters, loop switching rules or state machine thresholds are adaptively updated to compensate for the decrease in heat exchange capacity caused by hardware aging.

11. The battery thermal management control method according to claim 6, characterized in that: In battery heating mode: the waste heat recovery heat exchange component is activated first to heat the battery, and the auxiliary heating component is activated when the waste heat is insufficient to meet the temperature rise requirement; the decision on whether to activate the auxiliary heating component is based on the judgment result that the temperature rise rate is insufficient or the expected time to reach the target temperature exceeds the limit value.

12. The battery thermal management control method according to claim 6, characterized in that: In battery cooling mode: At least two heat exchange units are controlled to operate in coordination according to the current heat dissipation requirements, and the operating ratio of each heat exchange unit is dynamically adjusted according to the rate of temperature drop, so as to improve the utilization rate of cooling capacity and reduce energy redundancy.

13. The battery thermal management control method according to any one of claims 1-12, characterized in that: When the vehicle is charging and the vehicle is off or in standby mode: it continues to collect battery temperature and determine mode, and controls the liquid pump, valve body and heat exchange components; when a sensor abnormality or actuator abnormality is detected, it switches to a preset safety degradation strategy to limit the rate of battery temperature rise or limit the upper limit of battery temperature.

14. A battery thermal management system, characterized in that: A data acquisition module is used to acquire battery temperature parameters, coolant temperature parameters, and vehicle operating condition parameters; a decision module is used to determine the battery heating mode, battery temperature maintenance mode, or battery heat dissipation mode based on the parameters, and generate a circuit switching strategy; an execution control module is used to output control commands to the valve body and the liquid pump to switch the coolant flow circuit and drive the heat exchange components to work; wherein, the decision module is configured to execute the method described in any one of claims 1-13.

15. An electronic device, characterized in that: The invention includes a processor, a memory, and a computer program stored in the memory, which, when executed by the processor, implements the method of any one of claims 1-13; or, a readable storage medium having a computer program stored thereon, which, when executed by the processor, implements the method of any one of claims 1-13; or, a vehicle including the battery thermal management control system of claim 14.

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