Battery thermal management control method and battery thermal management system
By iteratively predicting cell temperature changes and adjusting the control strategy of the battery thermal management system, the problem of untimely temperature control under fixed parameter control is solved, thereby improving the energy efficiency of the battery thermal management system and the lifespan of the cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-25
- Publication Date
- 2026-04-07
AI Technical Summary
In existing battery thermal management systems, fixed parameter control is difficult to adapt to changes in cell temperature under different operating conditions, resulting in untimely temperature control, increased energy consumption, and impact on cell lifespan and energy efficiency.
By acquiring ambient temperature, initial cell temperature, and liquid outlet temperature, the system iteratively predicts cell temperature changes, adjusts preset start-up and stop temperatures, and optimizes the control strategy of the battery thermal management system to achieve more timely temperature regulation.
It has achieved a shift from post-event response to pre-event intervention, enabling it to proactively adapt to different operating conditions and accurately find the optimal balance between cell temperature control and system energy consumption, thereby improving the energy efficiency of the battery thermal management system.
Smart Images
Figure CN121812833A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery thermal management technology, and in particular to a battery thermal management control method and a battery thermal management system. Background Technology
[0002] Currently, battery thermal management typically employs a battery thermal management system with a water-cooled unit for temperature control. This system utilizes the phase change of refrigerant (such as water or coolant) in a closed loop to absorb or release heat, and then uses the refrigerant to carry the heat to the outside, thereby achieving efficient and stable active heat dissipation. Water-cooled units, due to their large heat dissipation capacity and uniform and stable temperature control, can meet the requirements for precise temperature control to a certain extent.
[0003] During battery charging and discharging, various temperature changes occur. In related technologies, the battery thermal management system has preset fixed control parameters, such as pre-set start-up and stop-down temperature thresholds. When a relevant temperature is detected, such as the battery cell temperature reaching or exceeding the start-up temperature, the battery thermal management system activates heating or cooling. When the temperature reaches or exceeds the stop-down temperature, the battery thermal management system deactivates heating or cooling, and so on.
[0004] However, this method of directly managing battery thermal based on preset fixed parameters is difficult to take into account the changes in cell temperature under different operating conditions. The adjustment is inflexible, and in the actual battery thermal management process, there will be situations where temperature control is performed too early or too late, resulting in increased energy consumption and untimely cell temperature control, which in turn cannot better guarantee the lifespan and energy efficiency of the cells. Summary of the Invention
[0005] The purpose of this application is to provide a battery thermal management control method and a battery thermal management system, so as to achieve battery temperature control more timely.
[0006] To address the aforementioned technical problems, embodiments of this application provide a battery thermal management control method applied to a battery thermal management system. The method includes: acquiring an ambient temperature, an initial cell temperature, and an initial liquid outlet temperature of the battery thermal management system; iteratively predicting the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature, wherein, in the iterative prediction, the operation of the battery thermal management system is simulated based on a preset start temperature and a preset stop temperature; adjusting the preset start temperature and / or the preset stop temperature based on the cell temperature during charging and discharging, so that the battery thermal management system activates a heat exchange function when the actual cell temperature reaches the adjusted preset start temperature, and / or stops the heat exchange function when the actual cell temperature reaches the adjusted preset stop temperature.
[0007] Embodiments of this application also provide a battery thermal management system, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the battery thermal management control method as described above.
[0008] The battery thermal management control method in this application acquires the ambient temperature, the initial cell temperature, and the outlet temperature of the battery thermal management system for thermal management of the battery. It then iteratively predicts the cell temperature during charging and discharging. Based on this iteratively predicted temperature, the effectiveness of existing control strategies is evaluated, and the start-up and shutdown temperatures of the battery thermal management system are adjusted. This allows for more precise control of the battery thermal management system and more timely temperature control of the battery. This method represents a shift from reactive to proactive intervention, actively adapting to different operating conditions and accurately finding the optimal balance between cell temperature control and system energy consumption. Ultimately, while ensuring battery safety and lifespan, it significantly improves the energy efficiency of the battery thermal management system. Attached Figure Description
[0009] Figure 1 A flowchart illustrating a battery thermal management control method provided in an embodiment of this application. Figure 1 ; Figure 2 A flowchart illustrating a battery thermal management control method provided in an embodiment of this application. Figure 2 ; Figure 3 A flowchart illustrating a battery thermal management control method provided in an embodiment of this application. Figure 3 ; Figure 4 A flowchart illustrating a battery thermal management control method provided in an embodiment of this application. Figure 4 ; Figure 5 A flowchart illustrating a battery thermal management control method provided in an embodiment of this application. Figure 5 ; Figure 6 A flowchart illustrating a battery thermal management control method provided in an embodiment of this application. Figure 6 ; Figure 7 A time-SoC curve provided for one embodiment of this application; Figure 8 A time-heating power curve provided for one embodiment of this application; Figure 9 This is a schematic diagram of the structure of a battery thermal management system provided in an embodiment of this application. Detailed Implementation
[0010] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.
[0011] In the description of this application, 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0012] In related technologies, the battery thermal management system is pre-set with fixed control parameters, such as a pre-set start-up temperature threshold and a stop temperature threshold. When a relevant temperature is detected, such as the battery cell temperature reaching or exceeding the start-up temperature, the battery thermal management system starts heating or cooling. When the temperature reaches or exceeds the stop temperature, the battery thermal management system shuts down heating or cooling, and so on.
[0013] In the battery thermal management system, when the battery needs to be cooled, a cell cooling start temperature and a cell cooling stop temperature are usually set. When the battery cell temperature rises to the cell cooling start temperature or exceeds the cell cooling start temperature, the cooling is turned on. When the cell temperature drops to the cell cooling stop temperature or exceeds the cell cooling stop temperature, the cooling is turned off.
[0014] Correspondingly, when the battery needs to heat up, a cell heating start temperature and a cell cooling heating temperature are usually set in the battery thermal management system. When the battery cell temperature is equal to or lower than (exceeds) the cell heating start temperature, heating is turned on. When the cell temperature rises to reach or exceed the cell cooling stop temperature, heating is turned off.
[0015] However, this method of directly managing battery thermal based on preset fixed parameters is difficult to take into account the changes in cell temperature under different operating conditions. The adjustment is inflexible, and in the actual battery thermal management process, there will be situations where temperature control is performed too early or too late, resulting in increased energy consumption and untimely cell temperature control, which in turn cannot better guarantee the lifespan and energy efficiency of the cells.
[0016] In view of this, this application proposes a battery thermal management control method, applied to a battery thermal management system. The method includes: acquiring an ambient temperature, an initial cell temperature, and an initial liquid outlet temperature of the battery thermal management system; iteratively predicting the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature, wherein, in the iterative prediction, the operation of the battery thermal management system is simulated based on a preset start temperature and a preset stop temperature; adjusting the preset start temperature and / or the preset stop temperature based on the cell temperature during charging and discharging, so that the battery thermal management system can activate the heat exchange function when the actual cell temperature reaches the adjusted preset start temperature, and / or deactivate the heat exchange function when the actual cell temperature reaches the adjusted preset stop temperature. The battery thermal management control method of this application acquires the ambient temperature, the initial cell temperature, and the liquid outlet temperature of the battery thermal management system for thermal management of the battery. Iteratively predicts the cell temperature during charging and discharging, evaluates the effectiveness of existing control strategies based on the predicted temperature, and adjusts the start-up and shutdown temperatures of the battery thermal management system. This allows for more precise control of the battery thermal management system and more timely temperature control of the battery. This method represents a shift from reactive to proactive intervention, actively adapting to different operating conditions and accurately finding the optimal balance between cell temperature control and system energy consumption. Ultimately, it significantly improves the energy efficiency of the battery thermal management system while ensuring battery safety and lifespan. The following details the implementation of the battery thermal management control method according to embodiments of this application. These details are provided for ease of understanding and are not essential for implementing this solution.
[0017] Reference Figure 1 As shown, Figure 1 This is a schematic flowchart illustrating a battery thermal management control method provided in one embodiment of this application. This application proposes a battery thermal management control method applied to a battery thermal management system.
[0018] The battery thermal management system described in this application uses a device based on a heat exchange fluid to manage battery temperature, such as the water-cooled unit mentioned above. It is understood that the heat exchange fluid can be water or other refrigerants, and battery temperature management can include heating or cooling. The water-cooled unit can include a compressor, evaporator, condenser, and throttling device, or other forms of devices, without limitation.
[0019] The method includes the following steps: Step 100: Obtain the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature of the battery thermal management system.
[0020] The battery thermal management system control method of this application can be applied to the process of starting battery charging and discharging or after charging and discharging has begun. At the moment this method is executed, the actual cell temperature collected is the initial cell temperature, and the actual liquid outlet temperature of the battery thermal management system is the initial liquid outlet temperature. In this embodiment, the liquid outlet temperature can be the temperature at which the battery thermal management system outputs heat exchange liquid to the heat exchange tube that exchanges heat with the battery. Correspondingly, the temperature of the liquid flowing out after heat exchange between the heat exchange tube and the battery is the liquid return temperature of the battery thermal management system. Ambient temperature refers to the temperature of the external environment in which the battery pack is located, such as the temperature of the space within the enclosure or chamber.
[0021] The actual cell temperature, liquid outlet temperature, and ambient temperature can be obtained by temperature sensors, such as thermocouples and thermistors, placed in appropriate locations.
[0022] Ambient temperature reflects the heat exchange conditions of the battery pack, directly affecting the efficiency of natural passive heat exchange and the active heat exchange of the battery thermal management system. The initial cell temperature characterizes the thermal state of the battery at the current moment and serves as a benchmark for predicting future temperature changes. The initial outlet temperature represents the cooling capacity or residual cooling capacity of the coolant in the battery thermal management system at the current moment. By obtaining these three key initial parameters, accurate initial state inputs are provided for subsequent predictions and decisions.
[0023] Step 200: Iteratively predict the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature, wherein the operation of the battery thermal management system is simulated based on a preset start temperature and a preset stop temperature during the iterative prediction.
[0024] This application employs an iterative prediction method, that is, based on the initial state obtained in step 100, it simulates the temperature change of the battery cell itself and gradually calculates the future battery cell temperature during the charging and discharging process. In each iteration, the heat dissipation of the battery cell is related to the ambient temperature and the temperature control of the battery thermal management system. Based on the preset start-up temperature and preset stop temperature, the operation of the battery thermal management system is simulated. It can be understood that the preset start-up temperature and preset stop temperature are artificially preset temperatures. Under this method, it is generally not involved in the actual control of the battery thermal management system based on the initially preset start-up temperature and preset stop temperature. Specifically, in the simulation, when the predicted battery cell temperature reaches the virtual preset start-up temperature (including the temperature exceeding the preset start-up temperature during cooling and the temperature falling below the preset start-up temperature during heating), the water-cooled unit is simulated to start, and its heat exchange effect is taken into account. When the predicted temperature reaches the virtual preset stop temperature (including the temperature falling below the preset stop temperature during cooling and the temperature exceeding the preset stop temperature during heating), the simulated unit is shut down. This simulation can more realistically reflect the dynamic changes in cell temperature and cooling system under the existing control strategy, and then iteratively obtain the cell temperature during charging and discharging by combining the ambient temperature and the heat generated by the cell itself.
[0025] Step 300: Adjust the preset start-up temperature and / or the preset stop temperature according to the cell temperature during charging and discharging, so that the battery thermal management system can start the heat exchange function when the actual cell temperature reaches the adjusted preset start-up temperature, and / or stop the heat exchange function when the actual cell temperature reaches the adjusted preset stop temperature.
[0026] Based on the cell temperature predicted during charging and discharging in step 200, the actual temperature change of the cell can be characterized to a certain extent. At this time, the temperature can be used to determine whether the current control parameters are suitable for implementing the subsequent battery thermal management system, and how to adjust it to obtain a more suitable cell temperature.
[0027] It can be understood that there are multiple predicted cell temperatures during charging and discharging. In this application, the temperature change relationship formed by one, multiple, or even multiple predicted cell temperatures during charging and discharging, such as the temperature change prediction curve, can be used to make a judgment, thereby realizing the adjustment of the preset start temperature and / or preset stop temperature.
[0028] In an optional embodiment, adjusting the preset start-up temperature and / or the preset stop temperature based on the cell temperature during charging and discharging includes: The preset start-up temperature and / or the preset stop temperature are adjusted according to the temperature of the battery cell at the end of charging and discharging.
[0029] In this embodiment, the adjustment decision can be made based on the final temperature of the cell during iteratively predicted charging and discharging, i.e., the temperature at the end of charging and discharging. Adjusting the preset start-up temperature and / or the preset stop temperature solely based on the cell temperature at the end of charging and discharging ensures timely battery temperature control and makes the control logic relatively simple and fast.
[0030] In an optional embodiment of this application, adjusting the preset start-up temperature and / or the preset stop temperature based on the temperature of the battery cell at the end of charging and discharging includes: When the temperature of the battery cell exceeds a preset temperature threshold at the end of charging and discharging, the preset start temperature is reduced to allow the battery thermal management system to start the heat exchange function in advance, and / or the preset stop temperature is reduced to allow the battery thermal management system to stop the heat exchange function in a delayed manner.
[0031] Specifically, taking the cooling of battery cells as an example, an ideal preset temperature threshold can be set. If the predicted cell temperature at the end of charging and discharging is too high, exceeding the preset temperature threshold, it indicates that the current preset start-up temperature is too high, cooling intervention is too late, or the preset stop temperature is too high, cooling stop time is too early. Therefore, the preset start-up temperature and / or preset stop temperature can be lowered, allowing the water-cooled unit to start cooling earlier and / or stop cooling later, thereby enhancing the cooling effect and preventing heat accumulation. Conversely, if the stop temperature is too low, it indicates the possibility of over-cooling. The system can raise the preset start-up temperature and / or preset stop temperature, allowing the unit to start cooling later and / or stop cooling earlier.
[0032] In other embodiments, adjustments can be made using multiple predicted temperatures or even the temperature change relationships formed by multiple temperatures. For example, multiple predicted temperatures can form a prediction curve. If the prediction curve exhibits one or more characteristics indicating insufficient timeliness in representing battery temperature, the preset start-up temperature and / or the preset stop temperature can be adjusted. For instance, if a prediction curve shows that the cell temperature will rise sharply and approach a set temperature comparison value, the current preset start-up temperature can be lowered accordingly, allowing the water-cooled unit to intervene in cooling earlier, thereby effectively preventing overheating. If the prediction shows that the temperature rises slowly for a period of time, and then the temperature rises significantly faster thereafter, the preset start-up temperature can be appropriately raised to avoid the unit starting too early and achieve energy saving.
[0033] Battery temperature control can involve more than just cooling. However, based on the physical characteristics of batteries during operation—that is, the battery will heat up whether it is charging or discharging—the cooling mode may account for a larger proportion of the heat exchange function in actual temperature control. However, heating the battery is not excluded. For example, in some battery discharge scenarios, it is necessary to heat the battery to reach a suitable temperature for discharge. Therefore, when iteratively predicting the battery cell temperature, the preset start temperature and preset stop temperature used for battery heating control can be judged based on the predicted temperature and then adjusted accordingly. The specific adjustment method can be set according to the actual situation, which will not be elaborated here.
[0034] Finally, the adjusted preset start temperature and / or the preset stop temperature are set as the heat exchange start / stop control parameters of the battery thermal management system, so that the battery thermal management system can perform heat exchange control based on this optimized, non-fixed threshold. That is, heat exchange is started when the actual cell temperature reaches the adjusted preset start temperature, and heat exchange is stopped when the adjusted preset stop temperature is reached.
[0035] It is understood that this application does not limit the adjustment of both the preset start temperature and the preset stop temperature. If the preset stop temperature is not adjusted, heat exchange will start based on the adjusted preset start temperature and stop based on the unadjusted preset stop temperature. Correspondingly, if the preset start temperature is not adjusted, heat exchange will start based on the unadjusted preset start temperature and stop based on the adjusted preset stop temperature.
[0036] Additionally, it should be noted that this application does not limit the battery thermal management system to start working only when the heat exchange function of the battery is activated, or to stop working when the heat exchange function of the battery is stopped. When heat exchange is not performed, it can also operate in other modes, such as circulation mode, in which the heat exchange fluid of the battery thermal management system circulates in the pipeline, but the battery thermal management system does not actively heat or cool the heat exchange fluid.
[0037] This application does not limit the adjustment of the preset start-up temperature and / or preset stop temperature to absolute precision, i.e., it does not require the battery thermal management system to achieve absolutely precise start-up and stop control based on the adjusted preset start-up temperature and / or preset stop temperature to ensure that the heat exchange function is not started or stopped too early or too late. Therefore, it is not absolutely necessary to numerically correlate the adjustment range of the preset start-up temperature and / or preset stop temperature with the cell temperature at the end of charging and discharging. In some cases, if it is determined that adjustment is necessary, the preset start-up temperature and / or preset stop temperature can be increased or decreased based on the preset adjustment range, thereby achieving relatively timely adjustment of the battery temperature. Of course, if there is a need for more precise battery temperature control, the specific values of the cell temperature during charging and discharging, such as one or more values, and the relationship between multiple values, can be combined with actual experience or simulation results to construct a relationship between temperature values and adjustment range and adjustment method (increase or decrease). This allows for more precise adjustment of the preset start-up temperature and / or the preset stop temperature based on the actual predicted temperature values to meet the temperature control requirements.
[0038] Furthermore, in specific implementations, this application can execute the steps of the scheme when the battery begins to charge or discharge, in order to adjust the preset start-up temperature and / or the preset stop temperature. During the charging and discharging process, the scheme can be executed again for further correction, thereby meeting more precise temperature control requirements.
[0039] In summary, the battery thermal management control method in this application obtains the ambient temperature, the initial cell temperature, and the liquid outlet temperature of the battery thermal management system for thermal management of the battery. It then iteratively predicts the cell temperature during charging and discharging, evaluates the effectiveness of existing control strategies based on the predicted temperature, and adjusts the start and stop temperatures of the battery thermal management system. This allows for more precise control of the battery thermal management system and more timely temperature control of the battery. This method represents a shift from reactive to proactive intervention, actively adapting to different operating conditions and accurately finding the optimal balance between cell temperature control and system energy consumption. Ultimately, while ensuring battery safety and lifespan, it significantly improves the energy efficiency of the battery thermal management system.
[0040] In an optional embodiment of this application, the step of iteratively predicting the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature includes: Based on the ambient temperature, the cell temperature at the current time point, and the liquid outlet temperature at the current time point, the liquid outlet temperature at the next time point is determined, wherein the cell temperature at the current time point includes the initial cell temperature, and the liquid outlet temperature at the current time point includes the initial liquid outlet temperature. The cell temperature at the next time point is determined based on the cell temperature at the current time point and the cell temperature change within a preset time period, wherein the preset time period is the time period from the current time point to the next time point. The heat exchange capacity of the battery thermal management system within the preset time period is determined based on the ambient temperature and the liquid outlet temperature at the start of the preset time period. The change in cell temperature within the preset time period is determined based on the ambient temperature, the heat generated by the cell within the preset time period, and the heat exchange within the preset time period.
[0041] In this embodiment, prediction is performed step-by-step based on dividing the entire charging and discharging process into different time nodes. Specifically, the node where prediction begins is taken as the initial time node. After the initial time node, the charging and discharging process can be divided into multiple time nodes. The time interval between adjacent time nodes is a preset time interval, which is the time interval from the current time node to the next time node. Thus, during the iteration process, the relevant parameters of each time node are calculated iteratively until the iteration is completed.
[0042] In one specific embodiment, the moment when the simulated cell charging and discharging ends is the final time node.
[0043] The above iterative steps, except that the prediction of one parameter depends on another parameter calculated in this iteration, do not require an absolute order and can be performed in parallel. Specifically, in the iterative calculation process, the final goal is to predict the cell temperature at the next time node. This temperature is calculated by combining the cell temperature at the current time node with the change in cell temperature from the current time node to the next time node (i.e., the preset time period). For example, the two can be summed. Therefore, the prediction of this part of the parameter has a specific order of calculation. However, the liquid outlet temperature at the next time node and the heat exchange within the preset time period can be calculated in parallel.
[0044] Specifically, determining the outlet temperature at the next time point can be based on the principle of heat exchange, where the outlet temperature is influenced by the ambient temperature, the current cell temperature, and the current outlet temperature. By establishing a thermodynamic relationship model between these three factors and the outlet temperature at the next time point (e.g., a simplified heat transfer formula considering coolant flow rate and heat exchanger efficiency), the dynamic change of the outlet temperature during the cycle can be calculated. The initial values are the ambient temperature, the initial cell temperature, and the initial outlet temperature obtained in step 100.
[0045] The heat exchange rate is determined within a preset time period. This heat exchange rate specifically refers to the cooling or heating capacity provided by the battery thermal management system (water-cooled unit). It is mainly related to the ambient temperature (which affects heat dissipation efficiency) and the outlet liquid temperature at the beginning of the preset time period (which reflects the current cooling / heating capacity of the system). It can be obtained by querying the heat exchange rate or heat exchange power mapping relationship pre-calibrated based on system characteristics or by applying empirical formulas.
[0046] To determine the temperature change of the battery cell within a preset time period, the temperature change is determined by the balance between heat generation and dissipation. Specifically, the heat generation of the battery cell can be calculated or estimated based on operating parameters such as current and internal resistance, or it can be determined based on the heat generation relationship of the cell during charging and discharging. For example, based on the time-SoC curve and the time-heat power curve, the heat generation of the current battery cell can be found within the preset time period by obtaining its SoC. Ambient temperature may affect the internal resistance heating and natural convection cooling of the cell. The heat exchange within the preset time period of the battery thermal management system represents the active cooling or heating of the cell. A temperature change model can be constructed, combining the relevant parameters of each time node or each time period, to solve for the temperature change of the cell within each time step, thereby driving the entire iterative prediction process.
[0047] For each iteration, the cell temperature at the next time point is determined. The cell temperature within a preset time period (e.g., 1 second) depends on the cell temperature at the current time point and the temperature change caused by the net heat absorbed or released during that time period. In an optional embodiment, the calculation formula is: Cell temperature at the next time point = Cell temperature at the current time point + Cell temperature change within the preset time period.
[0048] Reference Figure 2 As shown, in an optional embodiment of this application, determining the outlet temperature at the next time node based on the ambient temperature, the cell temperature at the current time node, and the outlet temperature at the current time node includes: Step 201: Determine the return temperature of the next time node based on the ambient temperature, the cell temperature at the current time node, and the liquid outlet temperature at the current time node. Step 202: Determine the outlet temperature of the next time node based on the return temperature of the next time node and the operating condition of the battery thermal management system. When the operating condition of the battery thermal management system is the heat exchange function condition, the outlet temperature of the next time node is determined based on the return temperature of the next time node and the heat exchange of the battery thermal management system within the preset time period.
[0049] In this embodiment, the return temperature refers to the temperature of the coolant that flows through the battery pack, completes heat exchange, and returns to the battery thermal management unit. Its value is primarily determined by the ambient temperature (affecting natural heat dissipation from the pipeline), the current cell temperature (heat source temperature), and the current outlet temperature (the initial temperature of the coolant flowing into the battery pack). By establishing a thermal balance relationship between these three factors and the return temperature, the temperature of the coolant after being heated or cooled by the cells can be calculated.
[0050] For the determined outlet temperature at the next time point, this step simulates the battery thermal management system's handling of the returning coolant. Throughout the iterative prediction process, the battery thermal management system is not always in a heating or cooling mode for the battery cells. As mentioned above, the battery thermal management system only enters the heating or cooling heat exchange state when the cell temperature reaches the preset start-up temperature, and exits the heating or cooling state when the cell temperature reaches the preset stop temperature. When not in heat exchange state, the battery thermal management system can be in standby or circulation state. Circulation state refers to the coolant flowing in the pipeline, but the battery thermal management system does not heat or cool the coolant. The calculation method for the outlet temperature at the next time point differs depending on the battery thermal management system's operating state. Specifically: When the system is in non-heat exchange mode, the outlet temperature is approximately equal to the return temperature.
[0051] When the system is in heat exchange mode (cooling or heating), the outlet temperature is determined by the return temperature at the next time point and the amount of heat exchange provided by the battery thermal management system within the preset time period. Specifically, in heating mode, the outlet temperature is the sum of the return temperature and the actual amount of heat applied to the coolant. This actual amount of heat applied to the coolant can be calculated based on the heat exchange within the preset time period, such as by combining flow rate and specific heat capacity to construct a formula. In cooling mode, the outlet temperature is the difference between the return temperature and the actual amount of cooling applied to the coolant. This actual amount of cooling applied to the coolant can also be calculated based on the heat exchange within the preset time period. The outlet temperature at the next time point is then obtained and used for calculating other parameters.
[0052] Reference Figure 3 As shown, in an optional embodiment of this application, determining the heat exchange capacity of the battery thermal management system within the preset time period based on the ambient temperature and the outlet liquid temperature at the start time point of the preset time period includes: Step 203: Determine the heat exchange power of the battery thermal management system based on the ambient temperature and the liquid outlet temperature at the start of the preset time period. Step 204: Determine the heat exchange within the preset time period based on the heat exchange power and the duration of the preset time period.
[0053] In this embodiment, heat exchange power refers to the amount of heat that the battery thermal management system can transfer per unit time. Its value is not fixed but dynamically depends on the ambient temperature and the outlet liquid temperature at the start of a preset time period (e.g., the outlet liquid temperature at the current time point). The system can dynamically determine this power value using a preset performance curve or heat exchange power mapping table. For example, in cooling mode, the higher the ambient temperature and the higher the outlet liquid temperature, the greater the unit's heat exchange power; conversely, it decreases. This mapping relationship accurately reflects the unit's instantaneous cooling capacity under different operating conditions.
[0054] In an optional embodiment, based on a heat exchange power mapping table, according to the ambient temperature and the outlet temperature at the start of the preset time period, in a specific heat exchange power mapping table, the first horizontal column of the table is the ambient temperature, the first vertical column is the outlet temperature, and the corresponding cells of the horizontal and vertical columns are the heat exchange power. If the values of the horizontal and vertical columns can be directly matched in the table, the power can be directly retrieved. If there are values that cannot be directly matched with the ambient temperature and outlet temperature in the table, calculations, such as difference calculations, can be performed to obtain the heat exchange power.
[0055] The heat exchange power mapping table can be preset according to the actual battery thermal management system. The heat exchange power mapping table is different for different battery thermal management systems, and no specific example is given here.
[0056] After obtaining the instantaneous heat exchange power for the current time period, the heat exchange can be calculated by multiplying the heat exchange power by the duration of the preset time period, i.e.: heat exchange = heat exchange power × duration, thus providing an accurate data basis for subsequent calculation of changes in cell temperature.
[0057] Reference Figure 4 As shown, in an optional embodiment of this application, the step of iteratively predicting the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature further includes: Step 200a: Divide the charging and discharging process of the battery cell into multiple time intervals according to the heat generation power of the battery cell during charging and discharging, wherein the heat generation power of the battery cell is consistent in each time interval; Step 200b: Divide each time interval into multiple preset time periods according to a preset unit duration.
[0058] Reference Figure 8As shown in a specific embodiment of this application, the charging and discharging process of the battery cell is divided into multiple time intervals based on the charge / discharge time-heating power curve of the battery cell. This curve is usually obtained from battery characteristic tests, with the horizontal axis representing time and the vertical axis representing heat generation power. It can be understood that the heat generation power of the battery cell is not constant throughout the entire charging and discharging process, but rather changes dynamically with factors such as its state of charge and current magnitude. The principle of division is to ensure that the heat generation power of the battery cell remains consistent or within a very small error range in each time interval.
[0059] After determining the time interval with constant heat generation power, to perform high-precision iterative prediction, each time interval is further subdivided into numerous, extremely short preset time periods (e.g., a preset unit duration of 2 seconds). Within each preset time period, since the heat generation power of the corresponding time interval is known and constant, the system can efficiently and accurately execute the aforementioned iterative calculation steps, thereby deducing the dynamic trajectory of cell temperature changes point by point throughout the entire charging and discharging process. This two-level division strategy ensures the accuracy of iterative prediction, thus facilitating more timely and accurate battery temperature control.
[0060] Reference Figure 5 As shown, in an optional embodiment of this application, the step of iteratively predicting the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature further includes: Step 200c: Determine the heat generation power of the battery cell during each preset time period based on the SoC of the battery cell; Step 200d: Determine the heat generation of the battery cell based on the heating power and the duration of the preset time period.
[0061] In an optional embodiment, based on the time-SoC curve of battery cell charging and discharging, and the temporal correlation in the time-heat power curve, the heat power of the battery in each preset time period is determined. When making a prediction at the current time node, the heat power in the preset time period after the current time node is determined, and then the heat generation of the cell is determined by combining the duration.
[0062] During the iterative prediction process, when it is necessary to determine the heat generation of the battery cell, the change of SOC during the charging and discharging of the battery cell can be determined, thereby determining the time period of the battery charging and discharging, and then determining the heat generation of the battery cell during that time period. For example, starting from the initial time node, the current actual SOC can be directly obtained, thereby determining the current battery cell heating power and subsequent heat generation. During the predicted charging and discharging process, the heat generation of the battery cell in each preset time period can be determined.
[0063] Reference Figure 7As shown, this is a time-SoC curve of a battery cell in a specific embodiment, where the horizontal axis represents time (in seconds) and the vertical axis represents SoC, with SoC of 1 indicating a full charge and 0 indicating an empty charge. (Refer to...) Figure 8 As shown, this is a time-heating power curve of a battery cell in a specific embodiment. The horizontal axis represents time (in seconds), and the vertical axis represents heat generation power (in watts). This curve can be obtained by analyzing the actual battery model and pre-setting it; however, the curve may differ for different batteries.
[0064] Reference Figure 6 As shown, in an optional embodiment of this application, determining the heat generation power of the battery cell during charging and discharging based on the SoC of the battery cell includes: Step 201c: Obtain the preset correlation between SoC and heat generation power, and obtain the charging and discharging influence parameters of the battery cell; Step 202c: Correct the preset correlation between SoC and heat generation power according to the charging and discharging influence parameters; Step 203c: Based on the correlation between the SoC of the battery cell and the corrected SoC and the heat generation power, determine the heat generation power of the battery cell during each preset time period during charging and discharging.
[0065] In one specific embodiment of this application, the preset correlation between the SoC and the heat dissipation power is as follows: Figure 7 and Figure 8 The time-SoC curve and time-heat power curve of the battery cell are shown. These curves are usually established through preliminary battery characteristic tests and reflect the baseline law of heat power change with SoC under standard test conditions.
[0066] It is understandable that in actual battery use, the SoC (System-on-Chips) and heat generation power are affected by battery usage and other external factors. Based on this, in this embodiment, the charging and discharging influencing factors of the battery cell are obtained, specifically including but not limited to the charge / discharge current rate, the state of health (SOH) of the battery cell, and ambient temperature. The obtained charging and discharging influencing parameters are used to dynamically correct the correlation of the above-mentioned benchmarks. For example, if the current charge / discharge current rate is higher than the standard rate used when establishing the baseline curve, the heat generation power value of the corresponding SoC point is increased according to a pre-stored correction algorithm or coefficient (such as a correction factor proportional to the square of the current), thereby obtaining a corrected correlation that better reflects the current actual operating conditions.
[0067] For each preset time period, the system only needs to determine the real-time SoC value of the battery cell in the current preset time period. Based on the correlation between the corrected SoC and the heat generation power, a more accurate heat generation power value can be output for subsequent heat generation calculation and temperature prediction.
[0068] Figure 9 This is a schematic diagram of a battery thermal management system provided in one embodiment of this application. Figure 9 As shown, another embodiment of this application proposes a battery thermal management system, which includes at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform the method described in the above method embodiment.
[0069] The memory and processor can be connected via a bus, which can include any number or type of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, which are well known in the art and therefore will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.
[0070] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. The memory can also be used to store data used by the processor during operation.
[0071] Another embodiment of this application relates to a computer-readable storage medium storing computer instructions that, when executed by a processor, implement the method described in the above-described method embodiments.
[0072] Another embodiment of this application relates to a computer program product, including a computer program that, when executed by a processor, implements the steps of the above-described method.
[0073] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.
[0074] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.
Claims
1. A battery thermal management control method, characterized in that, Applied to a battery thermal management system, the method includes: The ambient temperature, the initial cell temperature, and the initial outlet temperature of the battery thermal management system are obtained. The battery cell temperature during charging and discharging is iteratively predicted based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature. In the iterative prediction, the operation of the battery thermal management system is simulated based on a preset start temperature and a preset stop temperature. The preset start-up temperature and / or preset stop temperature are adjusted according to the cell temperature during charging and discharging, so that the battery thermal management system can start the heat exchange function when the actual cell temperature reaches the adjusted preset start-up temperature, and / or stop the heat exchange function when the actual cell temperature reaches the adjusted preset stop temperature.
2. The battery thermal management control method according to claim 1, characterized in that, The iterative prediction of the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature includes: Based on the ambient temperature, the cell temperature at the current time point, and the liquid outlet temperature at the current time point, the liquid outlet temperature at the next time point is determined, wherein the cell temperature at the current time point includes the initial cell temperature, and the liquid outlet temperature at the current time point includes the initial liquid outlet temperature. The cell temperature at the next time point is determined based on the cell temperature at the current time point and the cell temperature change within a preset time period, wherein the preset time period is the time period from the current time point to the next time point. The heat exchange capacity of the battery thermal management system within the preset time period is determined based on the ambient temperature and the liquid outlet temperature at the start of the preset time period. The change in cell temperature within the preset time period is determined based on the ambient temperature, the heat generated by the cell within the preset time period, and the heat exchange within the preset time period.
3. The battery thermal management control method according to claim 2, characterized in that, The step of determining the outlet temperature at the next time point based on the ambient temperature, the cell temperature at the current time point, and the outlet temperature at the current time point includes: The return temperature at the next time point is determined based on the ambient temperature, the cell temperature at the current time point, and the liquid outlet temperature at the current time point. The outlet temperature of the next time node is determined based on the return liquid temperature of the next time node and the operating condition of the battery thermal management system. When the operating condition of the battery thermal management system is the heat exchange function condition, the outlet temperature of the next time node is determined based on the return liquid temperature of the next time node and the heat exchange of the battery thermal management system within the preset time period.
4. The battery thermal management control method according to claim 2, characterized in that, The step of determining the heat exchange capacity of the battery thermal management system within the preset time period based on the ambient temperature and the outlet liquid temperature at the start time point of the preset time period includes: The heat exchange power of the battery thermal management system is determined based on the ambient temperature and the liquid outlet temperature at the start of the preset time period. The heat exchange capacity within the preset time period is determined based on the heat exchange power and the duration of the preset time period.
5. The battery thermal management control method according to claim 2, characterized in that, The method of iteratively predicting the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature further includes: The charging and discharging process of the battery cell is divided into multiple time intervals based on the heat generation power of the battery cell during charging and discharging, wherein the heat generation power of the battery cell is consistent in each time interval. Each time interval is divided into multiple preset time periods according to a preset unit duration.
6. The battery thermal management control method according to any one of claims 2-5, characterized in that, The method of iteratively predicting the cell temperature during charging and discharging based on the ambient temperature, the initial cell temperature, and the initial liquid outlet temperature further includes: The heat generation power of the battery cell during each preset time period is determined based on the SoC of the battery cell. The heat output of the battery cell is determined based on the heating power and the duration of the preset time period.
7. The battery thermal management control method according to claim 6, characterized in that, The step of determining the heat generation power of the battery cell during charging and discharging based on the SoC of the battery cell includes: Obtain the preset correlation between SoC and heat generation power, and obtain the charging and discharging influence parameters of the battery cell; The preset correlation between SoC and heat generation power is corrected based on the charging and discharging influence parameters; Based on the correlation between the SoC of the battery cell and the corrected SoC and the heat generation power, the heat generation power of the battery cell during each preset time period during charging and discharging is determined.
8. The battery thermal management control method according to any one of claims 1-5 and 7, characterized in that, The step of adjusting the preset start-up temperature and / or the preset stop temperature based on the cell temperature during charging and discharging includes: The preset start-up temperature and / or the preset stop temperature are adjusted according to the temperature of the battery cell at the end of charging and discharging.
9. The battery thermal management control method according to claim 8, characterized in that, The step of adjusting the preset start-up temperature and / or the preset stop temperature based on the temperature of the battery cell at the end of charging and discharging includes: When the temperature of the battery cell exceeds a preset temperature threshold at the end of charging and discharging, the preset start temperature is reduced to allow the battery thermal management system to start the heat exchange function in advance, and / or the preset stop temperature is reduced to allow the battery thermal management system to stop the heat exchange function in a delayed manner.
10. A battery thermal management system, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method as described in any one of claims 1 to 9.