Calibration Method and Device for Direct Cooling and Direct Heating Control Strategy of Power Battery System

Abstract

This application relates to the field of vehicle technology, and in particular to a method and apparatus for calibrating a direct cooling and heating control strategy for a power battery system. The method includes: determining the current calibration condition; performing bench calibration tests based on the current calibration condition to obtain cold plate data corresponding to the current calibration condition; performing index analysis based on the cold plate data corresponding to the current calibration condition; and, based on the analysis results, determining the strategy with the lowest energy consumption as the optimal control strategy for the current calibration condition. This solves the problem that related technologies using liquid cooling and liquid heating technologies for vehicle thermal management are limited by the high thermal resistance of the heat transfer medium and the high system complexity, resulting in insufficient heat transfer efficiency to meet rapid cooling requirements. This leads to uneven battery temperature distribution, excessively high local hot spot temperatures, and affects battery cycle life and safety. The method improves cooling or heating efficiency, control accuracy, and battery safety, while simultaneously reducing system energy consumption and development costs.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a method and apparatus for calibrating a direct cooling and direct heating control strategy for a power battery system. Background Technology

[0002] Currently, the main solution for vehicle thermal management systems is liquid cooling and liquid heating technology. The circulating fluid (50% ethylene glycol + 50% deionized water) is cooled by a plate heat exchanger chiiller, and then the circulating fluid cools the battery cells by passing through a liquid cooling plate; or, the circulating fluid is heated by a water-heating calorifier (WTC), and then the circulating fluid heats the battery cells by passing through a liquid cooling plate.

[0003] However, when related technologies use liquid cooling and liquid heating for vehicle thermal management, their heat transfer efficiency cannot meet the requirements for rapid cooling due to the high thermal resistance of the heat transfer medium and the high complexity of the system. This results in uneven battery temperature distribution and excessively high temperatures in local hot spots, affecting battery cycle life and safety, which urgently needs to be addressed. Summary of the Invention

[0004] This application provides a calibration method and apparatus for a direct cooling and heating control strategy of a power battery system. This addresses the problem that when related technologies use liquid cooling and liquid heating technologies for vehicle thermal management, the heat transfer efficiency cannot meet the requirements for rapid cooling due to the high thermal resistance of the heat transfer medium and the high system complexity. This results in uneven battery temperature distribution, excessively high temperatures in local hot spots, and affects battery cycle life and safety. The application aims to improve cooling or heating efficiency, control accuracy, and battery safety, while reducing system energy consumption and development costs.

[0005] The first aspect of this application provides a method for calibrating a direct cooling and direct heating control strategy for a power battery system, including the following steps: Determine the current calibration conditions; Based on the current calibration conditions, bench calibration tests are conducted to obtain the cold plate data corresponding to the current calibration conditions; Based on the cold plate data corresponding to the current calibration conditions, index analysis is performed, and based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration conditions.

[0006] Optionally, in some embodiments, the current calibration condition is a direct cooling calibration condition. Bench calibration tests are performed based on the current calibration condition to obtain the cold plate data corresponding to the current calibration condition, including: Based on the direct cooling calibration conditions, the current test conditions are determined, including the first ambient temperature, the simulated battery heat load, the pressure before the electronic expansion valve and the subcooling at the valve inlet, the evaporation temperature at the outlet of the direct cooling plate and the superheat at the outlet of the direct cooling plate. Based on the first ambient temperature, simulated battery heat load, inlet pressure and inlet subcooling of the electronic expansion valve, outlet evaporation temperature and outlet superheat of the direct cooling plate, bench calibration test is performed. When the first test end condition is met, the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel are recorded.

[0007] Optionally, in some embodiments, index analysis is performed based on the cold plate data corresponding to the current calibration condition, and based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration condition, including: Based on the preset maximum surface temperature threshold of the direct cooling plate, the preset temperature difference threshold of the first direct cooling plate, the preset direct cooling energy consumption threshold, and the preset direct cooling power threshold, the optimal control strategy for the current calibration condition is determined according to the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel.

[0008] Optionally, in some embodiments, the current calibration condition is a direct-heat calibration condition. Bench calibration tests are performed based on the current calibration condition to obtain the cold plate data corresponding to the current calibration condition, including: Based on the direct heating calibration conditions, the current test conditions are determined, including the second ambient temperature, heating power, simulated battery load, inlet superheat of the direct cooling plate, outlet condensation temperature of the direct cooling plate, and outlet subcooling of the direct cooling plate. Based on the second ambient temperature, heating power, simulated battery load, inlet superheat of the direct cooling plate, outlet condensation temperature of the direct cooling plate, and outlet subcooling of the direct cooling plate, bench calibration tests were conducted. When the second test termination condition was met, the outlet pressure of the second direct cooling plate, the flow resistance of the second system, the flow rate of the second system, the heat exchange of the second system, the surface temperature of the second direct cooling plate and the temperature difference between the second flow channel, the temperature of the dummy battery cell, and the temperature rise rate of the dummy battery cell were recorded.

[0009] Optionally, in some embodiments, index analysis is performed based on the cold plate data corresponding to the current calibration condition, and based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration condition, including: Based on preset dummy cell temperature rise rate, preset dummy cell temperature difference threshold, preset second direct cooling plate surface temperature difference threshold, preset direct heating energy consumption threshold, and preset direct heating power threshold, the optimal control strategy for the current calibration condition is determined according to the second direct cooling plate outlet pressure, second system flow resistance, second system flow rate, second heat exchange, second direct cooling plate surface temperature and second flow channel temperature difference, dummy cell temperature, and dummy cell temperature rise rate.

[0010] A second aspect of this application provides a calibration device for a direct cooling / heating control strategy of a power battery system, comprising: The acquisition module is used to determine the current calibration conditions; The testing module is used to perform bench calibration tests based on the current calibration conditions to obtain the cold plate data corresponding to the current calibration conditions. The determination module is used to perform index analysis based on the cold plate data corresponding to the current calibration operating condition, and based on the analysis results, determine the strategy with the lowest energy consumption value as the optimal control strategy for the current calibration operating condition.

[0011] Optionally, in some embodiments, the test module is specifically used for: Based on the direct cooling calibration conditions, the current test conditions are determined, including the first ambient temperature, the simulated battery heat load, the pressure before the electronic expansion valve and the subcooling at the valve inlet, the evaporation temperature at the outlet of the direct cooling plate and the superheat at the outlet of the direct cooling plate. Based on the first ambient temperature, simulated battery heat load, inlet pressure and inlet subcooling of the electronic expansion valve, outlet evaporation temperature and outlet superheat of the direct cooling plate, bench calibration test is performed. When the first test end condition is met, the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel are recorded.

[0012] Optionally, in some embodiments, the determining module is specifically used for: Based on the preset maximum surface temperature threshold of the direct cooling plate, the preset temperature difference threshold of the first direct cooling plate, the preset direct cooling energy consumption threshold, and the preset direct cooling power threshold, the optimal control strategy for the current calibration condition is determined according to the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel.

[0013] Optionally, in some embodiments, the test module is specifically used for: Based on the direct heating calibration conditions, the current test conditions are determined, including the second ambient temperature, heating power, simulated battery load, inlet superheat of the direct cooling plate, outlet condensation temperature of the direct cooling plate, and outlet subcooling of the direct cooling plate. Based on the second ambient temperature, heating power, simulated battery load, inlet superheat of the direct cooling plate, outlet condensation temperature of the direct cooling plate, and outlet subcooling of the direct cooling plate, bench calibration tests were conducted. When the second test termination condition was met, the outlet pressure of the second direct cooling plate, the flow resistance of the second system, the flow rate of the second system, the heat exchange of the second system, the surface temperature of the second direct cooling plate and the temperature difference between the second flow channel, the temperature of the dummy battery cell, and the temperature rise rate of the dummy battery cell were recorded.

[0014] Optionally, in some embodiments, the determining module is specifically used for: Based on preset dummy cell temperature rise rate, preset dummy cell temperature difference threshold, preset second direct cooling plate surface temperature difference threshold, preset direct heating energy consumption threshold, and preset direct heating power threshold, the optimal control strategy for the current calibration condition is determined according to the second direct cooling plate outlet pressure, second system flow resistance, second system flow rate, second heat exchange, second direct cooling plate surface temperature and second flow channel temperature difference, dummy cell temperature, and dummy cell temperature rise rate.

[0015] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the calibration method for the direct cooling and direct heating control strategy of the power battery system described in the first aspect embodiment.

[0016] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the calibration method for the direct cooling and direct heating control strategy of a power battery system as described in the first aspect embodiment.

[0017] Therefore, this application embodiment can obtain cold plate data corresponding to the current calibration condition through bench calibration testing and perform index analysis based on the current calibration condition. Then, based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration condition. This solves the problem that related technologies using liquid cooling / liquid heating technology for vehicle thermal management are limited by the high thermal resistance of the heat transfer medium and the high system complexity, resulting in insufficient heat transfer efficiency to meet rapid cooling requirements. This leads to uneven battery temperature distribution, excessively high local hot spot temperatures, and affects battery cycle life and safety. The solution improves cooling or heating efficiency, control accuracy, and battery safety, while reducing system energy consumption and development costs.

[0018] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a calibration method for a direct cooling and direct heating control strategy of a power battery system according to an embodiment of this application; Figure 2 This is a schematic diagram of a direct cooling control strategy calibration architecture according to an embodiment of this application; Figure 3 This is a schematic diagram of a direct-heating control strategy calibration architecture according to an embodiment of this application; Figure 4This is a flowchart illustrating a direct cooling and direct heating calibration method for a battery system according to an embodiment of this application; Figure 5 This is a block diagram of a calibration device for a direct cooling and direct heating control strategy of a power battery system according to an embodiment of this application; Figure 6 This is a schematic diagram of the structure of an electronic device according to an embodiment of this application. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0021] The following describes a calibration method and apparatus for a direct cooling / heating control strategy of a power battery system according to embodiments of this application, with reference to the accompanying drawings. Addressing the issues mentioned in the background art, where liquid cooling / heating technologies for vehicle thermal management involve multiple stages of indirect heat exchange, thermal resistance accumulation, and additional energy consumption from pumps, resulting in low cooling or heating efficiency, this application provides a calibration method for a direct cooling / heating control strategy of a power battery system. This method allows for bench calibration testing under current calibration conditions to obtain cold plate data corresponding to those conditions and performs index analysis. Based on the analysis results, the optimal control strategy for the current calibration conditions is determined by minimizing energy consumption. This solves the problem that related technologies using liquid cooling / heating technologies for vehicle thermal management suffer from limitations due to high thermal resistance of the heat transfer medium and high system complexity, resulting in insufficient heat transfer efficiency to meet rapid cooling requirements. This leads to uneven battery temperature distribution, excessively high local hotspot temperatures, and impacts battery cycle life and safety. The method improves cooling or heating efficiency, control accuracy, and battery safety while reducing system energy consumption and development costs.

[0022] Specifically, Figure 1 A flowchart illustrating the calibration method for the direct cooling and direct heating control strategy of a power battery system provided in this application embodiment.

[0023] like Figure 1 As shown, the calibration method for the direct cooling and direct heating control strategy of the power battery system includes the following steps: In step S101, the current calibration condition is determined.

[0024] Specifically, in the embodiments of this application, the current calibration condition can be determined by direct cooling calibration condition and direct heating calibration condition.

[0025] In step S102, bench calibration tests are performed based on the current calibration conditions to obtain the cold plate data corresponding to the current calibration conditions.

[0026] Optionally, in some embodiments, the current calibration condition is the direct cooling calibration condition. Bench calibration tests are performed based on the current calibration condition to obtain the corresponding cold plate data. This includes: determining the current test conditions based on the direct cooling calibration condition, wherein the current test conditions include a first ambient temperature, simulated battery heat load, the inlet pressure and inlet subcooling of the electronic expansion valve, the outlet evaporation temperature and outlet superheat of the direct cooling plate; performing bench calibration tests based on the first ambient temperature, simulated battery heat load, the inlet pressure and inlet subcooling of the electronic expansion valve, the outlet evaporation temperature and outlet superheat of the direct cooling plate, and recording the first direct cooling plate outlet pressure, the first system flow resistance, the first system flow rate, the first heat exchange, the first direct cooling plate surface temperature, and the first flow channel temperature difference when the first test termination condition is met.

[0027] Wherein, the first ambient temperature is the reference temperature value of the bench test environment under the direct cooling calibration condition; the first test termination condition is the pre-set judgment criterion for the completion of the bench test under the direct cooling calibration condition; the first direct cooling plate outlet pressure is the saturation pressure value of the refrigerant at the outlet of the direct cooling plate under the direct cooling calibration condition; the first system flow resistance is the pressure loss value generated by the refrigerant flowing through the system under the direct cooling calibration condition; the first system flow rate is the volume or mass of coolant flowing through the test system per unit time under the direct cooling calibration condition; the first heat exchange is the actual heat exchange power of the direct cooling plate calculated based on the refrigerant enthalpy difference under the direct cooling calibration condition; the first direct cooling plate surface temperature is the temperature data of the surface of the direct cooling plate under the direct cooling calibration condition; and the first flow channel temperature difference is the refrigerant temperature difference between the inlet and outlet positions of the flow channel of the direct cooling plate under the direct cooling calibration condition.

[0028] Figure 2 This is a schematic diagram of a direct cooling control strategy calibration architecture provided in one embodiment of this application. Figure 2 As shown, the calibration architecture of this direct cooling control strategy mainly consists of a compressor, condenser, electronic expansion valve, direct cooling and heating plate, heating film, gas-liquid separator, pressure-temperature sensor (PT), and flow meter. A temperature sensor is installed on the outer surface of the flow channel at the bottom of the direct cooling plate to monitor the temperature distribution within the flow channel. Simultaneously, a heating film is laid on the plane of the direct cooling plate to simulate the heating state of the battery cell. The heating film uses constant power output and executes the direct cooling control strategy under calibration conditions. After the battery system temperature reaches thermal equilibrium, the surface temperature distribution data of the direct cooling plate and the corresponding thermal management control strategy are recorded.

[0029] Specifically, in this embodiment, bench calibration tests can be performed based on the direct cooling control strategy calibration architecture. First, the heating power of the heating film on the surface of the direct cooling plate is set to a constant value, which can be determined with reference to the heating power of the battery system. At the same time, a temperature sensor is arranged on the surface of the direct cooling plate to record the temperature distribution on the surface of the direct cooling plate. Second, the pressure before the valve and the subcooling before the valve are set to fixed values. The outlet evaporation temperature is adjusted by controlling the outlet pressure. When the outlet evaporation temperature is 10°C, the corresponding saturation pressure is determined according to the refrigerant saturation temperature and pressure curve, and it is used as the set value of the outlet pressure of the direct cooling plate. Then, the outlet superheat is calibrated sequentially to 1°C, 2°C, 3°C, 4°C, and 5°C. When the surface temperature of the direct cooling plate reaches thermal equilibrium, and the inlet and outlet temperatures and pressures of the direct cooling plate reach equilibrium, the surface temperature, temperature difference, and heat exchange power of the direct cooling plate are recorded. The above steps are repeated, and the outlet evaporation temperature is set sequentially to 15°C and 20°C and the corresponding tests are completed. In addition, the main flow control methods for bench testing are: (1) when the temperature of the direct cooling plate is too high, increase the system flow rate; (2) when the temperature of the direct cooling plate is too low, reduce the system flow rate.

[0030] Furthermore, the cold plate data for the direct cooling calibration condition is composed of test conditions, specifically including the first ambient temperature, simulated battery heat load, inlet pressure and inlet subcooling of the electronic expansion valve, outlet evaporation temperature and outlet superheat of the direct cooling plate. In addition, the test results mainly include the inlet temperature of the first direct cooling plate, the inlet pressure of the first direct cooling plate, the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange rate, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel. Table 1 is a direct cooling calibration condition table provided in one embodiment of this application.

[0031] Table 1

[0032] Optionally, in some embodiments, the current calibration condition is a direct-heat calibration condition. Bench calibration tests are performed based on the current calibration condition to obtain the corresponding cold plate data. This includes: determining the current test conditions based on the direct-heat calibration condition, wherein the current test conditions include the second ambient temperature, heating power, simulated battery load, direct-cooling plate inlet superheat, direct-cooling plate outlet condensation temperature, and direct-cooling plate outlet subcooling; performing bench calibration tests based on the second ambient temperature, heating power, simulated battery load, direct-cooling plate inlet superheat, direct-cooling plate outlet condensation temperature, and direct-cooling plate outlet subcooling; and recording the second direct-cooling plate outlet pressure, second system flow resistance, second system flow rate, second heat exchange, second direct-cooling plate surface temperature, second flow channel temperature difference, dummy cell temperature, and dummy cell temperature rise rate when the second test termination condition is met.

[0033] Wherein, the second ambient temperature is the reference temperature value of the bench test environment under direct heating calibration conditions; the second test termination condition is the pre-set judgment criterion for the completion of the bench test under direct heating calibration conditions; the second direct cooling plate outlet pressure is the saturation pressure value of the refrigerant at the outlet of the direct cooling plate under direct heating calibration conditions; the second system flow resistance is the pressure loss value generated by the refrigerant flowing through the system under direct heating calibration conditions; the second system flow rate is the volume or mass of coolant flowing through the test system per unit time under direct heating calibration conditions; the second heat exchange is the actual heat exchange power of the direct cooling plate calculated based on the refrigerant enthalpy difference under direct heating calibration conditions; the second direct cooling plate surface temperature is the temperature data of the surface of the direct cooling plate under direct heating calibration conditions; and the second flow channel temperature difference is the refrigerant temperature difference between the inlet and outlet positions of the flow channel of the direct cooling plate under direct heating calibration conditions.

[0034] Figure 3 This is a schematic diagram of a direct-heating control strategy calibration architecture provided in one embodiment of this application. Figure 3 As shown, the calibration architecture of this direct-heating control strategy mainly consists of a compressor, an electronic expansion valve, a direct-cooling and direct-heating plate, a dummy battery cell, a chiller, a gas-liquid separator, a PT sensor, and a flow meter. The direct-heating plate is equipped with a dummy battery cell, which acts as a heat capacity component to absorb heat from the direct-heating plate and absorbs external heat through the chiller. By setting the direct-heating operating conditions to simulate the battery cell heating process, and after executing the operation according to the calibration strategy, the pressure and temperature of the refrigerant at the inlet and outlet of the direct-cooling plate are monitored in real time. Once thermal equilibrium is reached and the battery cell temperature rise tends to stabilize, information such as the pressure and temperature at the inlet and outlet of the direct-cooling plate, the compression flow rate, the subcooling degree at the outlet of the direct-cooling plate, and the opening degree of the electronic expansion valve are collected.

[0035] Specifically, in this embodiment, bench calibration tests can be performed based on the direct-heat control strategy calibration architecture. First, dummy battery cells are placed on the surface of the direct-cooling plate to simulate a battery cell load, and temperature sensors are installed on the surface of the direct-cooling plate to record the temperature distribution. The outlet condensing temperature of the direct-cooling plate is controlled by adjusting the outlet pressure. Second, the inlet superheat of the direct-cooling plate is set to a fixed value. When the outlet condensing temperature is 50°C, the corresponding saturation pressure is determined based on the refrigerant saturation temperature and pressure curve, and this is used as the setpoint for the outlet pressure of the direct-cooling plate. Subsequently, the outlet supercooling is calibrated sequentially to 1°C, 2°C, 3°C, 4°C, and 5°C. When the surface temperature of the direct-cooling plate reaches thermal equilibrium, and the inlet and outlet temperatures and pressures of the direct-cooling plate reach equilibrium, the surface temperature, temperature difference, and heat exchange power of the direct-cooling plate are recorded. The above steps are repeated, with the outlet condensing temperature sequentially set to 55°C and 45°C, and the corresponding tests are completed. In addition, the main flow control methods for bench testing are: (1) when the direct heating rate is too low, increase the system flow rate; (2) when the direct cooling rate is too high, reduce the system flow rate.

[0036] Furthermore, the cold plate data for the direct-heat calibration condition is composed of test conditions, specifically including the second ambient temperature, heating power, simulated battery load, direct-cooling plate inlet superheat, direct-cooling plate outlet condensation temperature, and direct-cooling plate outlet subcooling. In addition, the test results mainly include the second direct-cooling plate inlet temperature, second direct-cooling plate inlet pressure, second direct-cooling plate outlet pressure, second system flow resistance, second system flow rate, second heat exchange, second flow channel temperature difference, dummy cell temperature rise rate, and dummy cell temperature. Table 2 is a direct-heat calibration condition table provided in one embodiment of this application.

[0037] Table 2

[0038] In step S103, index analysis is performed based on the cold plate data corresponding to the current calibration condition, and based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration condition.

[0039] Optionally, in some embodiments, index analysis is performed based on the cold plate data corresponding to the current calibration condition, and based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration condition. This includes: determining the optimal control strategy for the current calibration condition based on the preset maximum surface temperature threshold of the direct cooling plate, the preset first surface temperature difference threshold of the direct cooling plate, the preset direct cooling energy consumption threshold, and the preset direct cooling power threshold, and based on the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the first heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel.

[0040] Among them, the preset maximum temperature threshold of the direct cooling plate surface is the maximum allowable temperature limit of the direct cooling plate surface under the preset direct cooling calibration conditions; the preset first temperature difference threshold of the direct cooling plate surface is the maximum allowable temperature difference between different measuring points on the direct cooling plate surface; the preset direct cooling energy consumption threshold or direct cooling power threshold is the allowable energy consumption limit and the heat exchange power limit to be met under the preset direct cooling calibration conditions.

[0041] Specifically, under the direct cooling calibration conditions, this embodiment of the application can perform index analysis based on the cold plate data and determine the optimal control strategy. Specifically, when the calibration conditions reach thermal equilibrium, the highest surface temperature of the direct cooling plate needs to be controlled within the index Tmax-L, the surface temperature difference of the direct cooling plate needs to be controlled within the index Tdiff-L, the direct cooling energy consumption needs to be controlled within the index PL, and the direct cooling power needs to be greater than the index QL. When the highest temperature index Tmax-L, the surface temperature difference index Tdiff-L, the direct cooling power index QL, and the direct cooling energy consumption index PL are all satisfied, the strategy with the lowest energy consumption value is selected as the optimal control strategy, and this strategy is filled in Table 3. Meanwhile, during the calibration process, the superheat at the outlet of the direct cooling plate must be controlled within 5°C; to ensure that the temperature difference between the inlet and outlet of the direct cooling plate is within a small range, the pressure drop of the direct cooling plate must be controlled within 150 kPa; to ensure the enthalpy difference of the refrigerant, the subcooling before the expansion valve must be controlled above 5°C, and the pressure before the expansion valve must be controlled at 1600 kPa. Table 3 shows a battery direct cooling control strategy provided in one embodiment of this application.

[0042] Table 3

[0043] Optionally, in some embodiments, index analysis is performed based on the cold plate data corresponding to the current calibration condition, and based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration condition. This includes: determining the optimal control strategy for the current calibration condition based on the preset dummy cell temperature rise rate, preset dummy cell temperature difference threshold, preset second direct cold plate surface temperature difference threshold, preset direct heating energy consumption threshold, and preset direct heating power threshold, and based on the second direct cold plate outlet pressure, second system flow resistance, second system flow rate, second heat exchange, second direct cold plate surface temperature and second flow channel temperature difference, dummy cell temperature, and dummy cell temperature rise rate.

[0044] Among them, the preset dummy cell temperature rise rate or dummy cell temperature difference threshold is the preset allowable temperature rise rate and temperature difference limit of the dummy cell under the direct heating calibration condition; the preset second direct cooling plate surface temperature difference threshold is the preset maximum allowable temperature difference between different measuring points on the direct cooling plate surface; the preset direct heating energy consumption threshold or direct heating power threshold is the preset allowable energy consumption limit and the heat exchange power limit to be met under the direct heating calibration condition.

[0045] Specifically, under direct heating calibration conditions, this embodiment of the application can perform index analysis and determine the optimal control strategy based on the cold plate data. Specifically, when the calibration conditions reach thermal equilibrium, the temperature rise rate of the dummy battery cell must be higher than the temperature rise rate index Vt-R, the temperature difference of the dummy battery cell must be controlled within the index CTdiff-R, the surface temperature difference of the direct cooling plate must be controlled within the index Tdiff-R, the direct heating energy consumption must be controlled within the index PR, and the direct heating power must be greater than the index QR. When the temperature rise rate index Vt-R, the dummy battery cell temperature difference index CTdiff-R, the surface temperature difference of the direct cooling plate index Tdiff-R, the direct heating power index QR, and the direct heating energy consumption index PR are all satisfied, the strategy with the lowest energy consumption value is selected as the optimal control strategy, and this strategy is recorded in Table 4. Meanwhile, during the calibration process, the subcooling at the outlet of the direct cooling plate must be controlled within 5°C; to ensure that the temperature difference between the inlet and outlet of the direct cooling plate is within a small range, the pressure drop of the direct cooling plate must be controlled within 150 kPa; to ensure the enthalpy difference of the refrigerant, the superheat at the inlet of the direct cooling plate must be controlled within 5°C; and to avoid the safety risks to the battery cell caused by excessively high inlet temperature of the direct cooling plate, the maximum inlet temperature must be controlled within 65°C. Table 4 shows a battery direct heating control strategy provided in one embodiment of this application.

[0046] Table 4

[0047] Furthermore, during the calibration process, this embodiment requires inputting the corresponding heat generation power and heating power for different operating conditions. The resulting direct cooling and heating control strategy is shown in Table 5. After completing the calibration of the battery system's direct cooling and heating control strategy, the control strategy is output to the vehicle thermal management controller to conduct vehicle thermal management calibration tests, ultimately realizing the application of the direct cooling and heating control strategy. Table 5 is a direct cooling and heating control strategy table provided by one embodiment of this application.

[0048] Table 5

[0049] Therefore, this application adopts a direct cooling and heating technology solution. The refrigerant evaporates within the battery's direct cooling plate to achieve rapid cooling of the battery cell, and condenses within the plate to achieve rapid heating. The latent heat of phase change of the refrigerant directly acts on the battery cell to complete the cooling or heating operation, significantly improving cooling and heating efficiency. Simultaneously, this application specifies the temperature and pressure parameters for direct cooling / heating control of the battery, ensuring the battery system always operates within the optimal temperature range and effectively reducing system energy consumption. Furthermore, adopting a direct cooling and heating solution for the entire vehicle can reduce the overall cost of the thermal management architecture, especially suitable for mid-to-low-end models, thereby improving control precision and further reducing system energy consumption.

[0050] Furthermore, to enable those skilled in the art to better understand the calibration method for the direct cooling and direct heating control strategy of the power battery system of this application, the following description is provided in conjunction with specific embodiments.

[0051] Specifically, since there are many design control parameters for direct cooling and heating of battery systems, detailed calibration of the direct cooling and heating control strategy is required to ensure that the battery system can still achieve the preset performance under the worst operating conditions, while ensuring the safe operation of the battery system. Therefore, this application proposes a battery system calibration strategy to achieve the battery direct cooling and heating calibration target. The calibration target parameters of the battery direct cooling and heating control strategy are shown in Table 6, which is a calibration target parameter table for a battery direct cooling and heating control strategy provided in one embodiment of this application.

[0052] Table 6

[0053] Furthermore, after completing the calibration of the direct cooling and direct heating conditions, this embodiment of the application can monitor whether the various indicators listed in Table 7 are met, and simultaneously select the scheme with the lowest energy consumption, thereby determining the optimal control strategy. Table 7 is a calibration indicator table for a battery direct cooling and direct heating control strategy provided in one embodiment of this application.

[0054] Table 7

[0055] Furthermore, energy consumption indicators can be calculated by multiplying the compressor voltage and current: P=U*I; Where P is the compressor energy consumption; U is the compressor voltage; and I is the compressor current.

[0056] Furthermore, both the direct cooling power and the direct heating power can be obtained by calculating the enthalpy difference and flow rate of the refrigerant at the inlet and outlet of the direct cooling / heating plate: Q = ΔH * q; Where Q is the compressor energy consumption; ΔH is the enthalpy difference before and after the direct cooling and heating plates; and q is the refrigerant flow rate.

[0057] Furthermore, this application embodiment compares and tests two technical solutions—direct cooling / heating and liquid cooling / heating—under high-temperature fast charging conditions, and the results are shown in Table 8. Compared to the liquid cooling / heating solution, the direct cooling / heating solution of this application embodiment has higher heat exchange efficiency and achieves the target temperature in a shorter time. It should be understood that the same control objective can be achieved by adjusting the control parameters.

[0058] Table 8

[0059] Furthermore, to enable those skilled in the art to better understand the calibration method for the direct cooling and direct heating control strategy of the power battery system of this application, the following is combined with... Figure 4 Specific embodiments will be described below.

[0060] Figure 4 This is a flowchart of a direct cooling and direct heating calibration method for a battery system provided in one embodiment of this application.

[0061] like Figure 4 As shown, the direct cooling and direct heating calibration method for this battery system includes the following steps: S401, Determine calibration conditions.

[0062] S402, determine the heating power of the battery cell.

[0063] S403, Calibration Strategy Input.

[0064] S404, Determine if the objective has been achieved? If yes, proceed to step S405; otherwise, proceed to step S403.

[0065] S405, Determine if this is the optimal strategy? If yes, proceed to step S406; otherwise, proceed to step S403.

[0066] S406, Determine the optimal control strategy.

[0067] Specifically, in the direct cooling calibration process, this embodiment first determines the ambient temperature and calibration conditions, then sets the high-temperature fast charging operating conditions based on the battery system; subsequently, it determines the evaporation temperature and sets different outlet superheats for testing, while simultaneously monitoring the battery system's maximum temperature, system temperature difference, thermal equilibrium achievement time, and power consumption parameters. Finally, based on meeting the system's maximum temperature and temperature difference requirements, it selects the scheme with the shortest thermal equilibrium achievement time and the lowest power consumption to determine the optimal control strategy. The direct heating calibration process, on the other hand, first determines the ambient temperature and calibration conditions, then sets the low-temperature fast charging operating conditions based on the battery system; subsequently, it determines the condensation temperature and sets different outlet supercools for testing, while simultaneously monitoring the battery system's temperature rise rate, system temperature difference, charging time, and power consumption parameters. Finally, based on meeting the system's temperature rise rate and temperature difference requirements, it selects the scheme with the shortest charging time and the lowest power consumption to determine the optimal control strategy.

[0068] The calibration method for direct cooling and heating control strategies of power battery systems proposed in this application can obtain cold plate data corresponding to the current calibration conditions through bench calibration tests and perform index analysis. Based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration conditions. This solves the problem that related technologies using liquid cooling and liquid heating technologies for vehicle thermal management are limited by the high thermal resistance of the heat transfer medium and the high system complexity, resulting in insufficient heat transfer efficiency to meet rapid cooling requirements. This leads to uneven battery temperature distribution, excessively high local hot spot temperatures, and affects battery cycle life and safety. The method improves cooling or heating efficiency, control accuracy, and battery safety while reducing system energy consumption and development costs.

[0069] Next, referring to the accompanying drawings, the calibration device for the direct cooling and direct heating control strategy of the power battery system proposed in the embodiments of this application is described.

[0070] Figure 5 This is a block diagram of the calibration device for the direct cooling and direct heating control strategy of the power battery system proposed in the embodiments of this application.

[0071] like Figure 5 As shown, the calibration device 10 for the direct cooling and direct heating control strategy of the power battery system includes: an acquisition module 100, a test module 200, and a determination module 300.

[0072] The acquisition module 100 is used to determine the current calibration condition; the test module 200 is used to perform bench calibration tests based on the current calibration condition to obtain the cold plate data corresponding to the current calibration condition; and the determination module 300 is used to perform index analysis based on the cold plate data corresponding to the current calibration condition, and based on the analysis results, determine the strategy with the lowest energy consumption value as the optimal control strategy for the current calibration condition.

[0073] Optionally, in some embodiments, the test module 200 is specifically used to: determine the current test conditions based on the direct cooling calibration conditions, wherein the current test conditions include a first ambient temperature, simulated battery heat load, the pressure before the electronic expansion valve and the subcooling at the inlet of the electronic expansion valve, the evaporation temperature at the outlet of the direct cooling plate and the superheat at the outlet of the direct cooling plate; perform bench calibration tests based on the first ambient temperature, simulated battery heat load, the pressure before the electronic expansion valve and the subcooling at the inlet of the electronic expansion valve, the evaporation temperature at the outlet of the direct cooling plate and the superheat at the outlet of the direct cooling plate, and record the first direct cooling plate outlet pressure, the first system flow resistance, the first system flow rate, the first heat exchange, the first direct cooling plate surface temperature and the first flow channel temperature difference when the first test termination condition is met.

[0074] Optionally, in some embodiments, the determining module 300 is specifically used to: determine the optimal control strategy for the current calibration condition based on the preset maximum surface temperature threshold of the direct cooling plate, the preset first surface temperature difference threshold of the direct cooling plate, the preset direct cooling energy consumption threshold, and the preset direct cooling power threshold, according to the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the first heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel.

[0075] Optionally, in some embodiments, the test module 200 is specifically used to: determine the current test conditions based on the direct heating calibration conditions, wherein the current test conditions include the second ambient temperature, heating power, simulated battery load, direct cooling plate inlet superheat, direct cooling plate outlet condensation temperature, and direct cooling plate outlet subcooling; perform bench calibration tests based on the second ambient temperature, heating power, simulated battery load, direct cooling plate inlet superheat, direct cooling plate outlet condensation temperature, and direct cooling plate outlet subcooling, and record the second direct cooling plate outlet pressure, second system flow resistance, second system flow rate, second heat exchange, second direct cooling plate surface temperature and second flow channel temperature difference, dummy cell temperature, and dummy cell temperature rise rate when the second test termination condition is met.

[0076] Optionally, in some embodiments, the determining module 300 is specifically used to: determine the optimal control strategy for the current calibration condition based on the preset dummy cell temperature rise rate, preset dummy cell temperature difference threshold, preset second direct cooling plate surface temperature difference threshold, preset direct heating energy consumption threshold, and preset direct heating power threshold, according to the second direct cooling plate outlet pressure, second system flow resistance, second system flow rate, second heat exchange, second direct cooling plate surface temperature and second flow channel temperature difference, dummy cell temperature, and dummy cell temperature rise rate.

[0077] It should be noted that the foregoing explanation of the embodiment of the calibration method for the direct cooling and heating control strategy of the power battery system also applies to the calibration device for the direct cooling and heating control strategy of the power battery system in this embodiment, and will not be repeated here.

[0078] The calibration device for direct cooling and heating control strategies of power battery systems proposed in this application can obtain cold plate data corresponding to the current calibration conditions through bench calibration tests and perform index analysis based on the analysis results. The optimal control strategy for the current calibration conditions is then determined based on the strategy that minimizes energy consumption. This solves the problem that related technologies using liquid cooling and liquid heating for vehicle thermal management suffer from limitations due to the high thermal resistance of the heat transfer medium and the high system complexity, resulting in uneven battery temperature distribution, excessively high local hotspot temperatures, and impacts battery cycle life and safety. The device improves cooling or heating efficiency, control accuracy, and battery safety while reducing system energy consumption and development costs.

[0079] Figure 6A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include: The memory 601, the processor 602, and the computer program stored on the memory 601 and capable of running on the processor 602.

[0080] When the processor 602 executes the program, it implements the calibration method for the direct cooling and direct heating control strategy of the power battery system provided in the above embodiments.

[0081] Furthermore, the electronic device also includes: Communication interface 603 is used for communication between memory 601 and processor 602.

[0082] The memory 601 is used to store computer programs that can run on the processor 602.

[0083] The memory 601 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0084] If the memory 601, processor 602, and communication interface 603 are implemented independently, then the communication interface 603, memory 601, and processor 602 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0085] Optionally, in a specific implementation, if the memory 601, processor 602, and communication interface 603 are integrated on a single chip, then the memory 601, processor 602, and communication interface 603 can communicate with each other through an internal interface.

[0086] The processor 602 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0087] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the following... Figure 1 The calibration method for the direct cooling and direct heating control strategy of the power battery system is shown.

[0088] In the description of this specification, the 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 this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0089] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0090] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0091] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0092] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0093] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0094] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0095] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A calibration method for a direct cooling / heating control strategy of a power battery system, characterized in that, Includes the following steps: Determine the current calibration conditions; Based on the current calibration conditions, bench calibration tests are performed to obtain the cold plate data corresponding to the current calibration conditions; Based on the cold plate data corresponding to the current calibration condition, an index analysis is performed, and based on the analysis results, the strategy with the lowest energy consumption value is determined as the optimal control strategy for the current calibration condition.

2. The method according to claim 1, characterized in that, The current calibration condition is the direct cooling calibration condition. The step of performing bench calibration tests based on the current calibration condition to obtain the cold plate data corresponding to the current calibration condition includes: Based on the direct cooling calibration conditions, the current test conditions are determined, including the first ambient temperature, the simulated battery heat load, the pressure before the electronic expansion valve and the subcooling at the valve inlet, the evaporation temperature at the outlet of the direct cooling plate and the superheat at the outlet of the direct cooling plate. Based on the first ambient temperature, the simulated battery heat load, the inlet pressure and inlet subcooling of the electronic expansion valve, the outlet evaporation temperature and outlet superheat of the direct cooling plate, bench calibration tests are performed, and when the first test termination condition is met, the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel are recorded.

3. The method of claim 2, wherein, The step of performing index analysis based on the cold plate data corresponding to the current calibration condition, and determining the strategy with the lowest energy consumption value as the optimal control strategy for the current calibration condition based on the analysis results, includes: Based on the preset maximum surface temperature threshold of the direct cooling plate, the preset surface temperature difference threshold of the first direct cooling plate, the preset direct cooling energy consumption threshold, and the preset direct cooling power threshold, the optimal control strategy for the current calibration condition is determined according to the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange of the first system, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel.

4. The method of claim 1, wherein, The current calibration condition is a direct-heat calibration condition. The step of performing bench calibration tests based on the current calibration condition to obtain the corresponding cold plate data includes: Based on the direct heating calibration conditions, the current test conditions are determined, including the second ambient temperature, heating power, simulated battery load, direct cooling plate inlet superheat, direct cooling plate outlet condensation temperature, and direct cooling plate outlet subcooling. Based on the second ambient temperature, the heating power, the simulated battery load, the inlet superheat of the direct cooling plate, the outlet condensation temperature of the direct cooling plate, and the outlet subcooling of the direct cooling plate, bench calibration tests are performed. When the second test termination condition is met, the outlet pressure of the second direct cooling plate, the flow resistance of the second system, the flow rate of the second system, the heat exchange of the second system, the surface temperature of the second direct cooling plate and the temperature difference between the second flow channel, the temperature of the dummy battery cell, and the temperature rise rate of the dummy battery cell are recorded.

5. The method of claim 4, wherein, The step of performing index analysis based on the cold plate data corresponding to the current calibration condition, and determining the strategy with the lowest energy consumption value as the optimal control strategy for the current calibration condition based on the analysis results, includes: Based on preset dummy cell temperature rise rate, preset dummy cell temperature difference threshold, preset second direct cooling plate surface temperature difference threshold, preset direct heating energy consumption threshold, and preset direct heating power threshold, the optimal control strategy for the current calibration condition is determined according to the second direct cooling plate outlet pressure, the second system flow resistance, the second system flow rate, the second heat exchange, the second direct cooling plate surface temperature and the second flow channel temperature difference, the dummy cell temperature, and the dummy cell temperature rise rate.

6. A power battery system direct cooling and direct heating control strategy calibration device, characterized in that, include: The acquisition module is used to determine the current calibration conditions; The testing module is used to perform bench calibration tests based on the current calibration conditions to obtain the cold plate data corresponding to the current calibration conditions. The determination module is used to perform index analysis based on the cold plate data corresponding to the current calibration condition, and based on the analysis results, determine the strategy with the lowest energy consumption value as the optimal control strategy for the current calibration condition.

7. The apparatus of claim 6, wherein, The test module is specifically used for: Based on the direct cooling calibration conditions, the current test conditions are determined, including the first ambient temperature, the simulated battery heat load, the pressure before the electronic expansion valve and the subcooling at the valve inlet, the evaporation temperature at the outlet of the direct cooling plate and the superheat at the outlet of the direct cooling plate. Based on the first ambient temperature, the simulated battery heat load, the inlet pressure and inlet subcooling of the electronic expansion valve, the outlet evaporation temperature and outlet superheat of the direct cooling plate, bench calibration tests are performed, and when the first test termination condition is met, the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel are recorded.

8. The apparatus of claim 6, wherein, The determining module is specifically used for: Based on the preset maximum surface temperature threshold of the direct cooling plate, the preset surface temperature difference threshold of the first direct cooling plate, the preset direct cooling energy consumption threshold, and the preset direct cooling power threshold, the optimal control strategy for the current calibration condition is determined according to the outlet pressure of the first direct cooling plate, the flow resistance of the first system, the flow rate of the first system, the heat exchange, the surface temperature of the first direct cooling plate, and the temperature difference of the first flow channel.

9. An electronic device, comprising: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the calibration method for the direct cooling and direct heating control strategy of a power battery system as described in any one of claims 1-5.

10. A computer-readable storage medium storing a computer program, characterized in that, When executed by the processor, the program implements the calibration method for the direct cooling and direct heating control strategy of the power battery system as described in any one of claims 1-5.

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