Thermal management method based on cell temperature difference and air-cooled battery system

Abstract

According to the thermal management method based on the battery cell temperature difference and the air-cooled battery system, an air conditioner connected with a battery cabin is controlled to enter a refrigeration or heating operation strategy according to the highest battery cell temperature, the lowest battery cell temperature, a preset refrigeration starting threshold value and a preset heating starting threshold value; the maximum temperature difference of the battery cell is calculated in real time, a refrigeration stop threshold value and a heating stop threshold value are adjusted according to the current operation strategy of the air conditioner, the minimum battery cell temperature and the maximum battery cell temperature, and the air conditioning system stops refrigeration and heating when the maximum temperature difference of the battery cell exceeds a preset temperature difference threshold value; battery thermal management can be carried out based on cell temperature difference, and the cell temperature difference problem is solved.

Description

[0001] This is a divisional application of the invention patent with the application date of December 8, 2023, the application number of 202311686669.6, and the title of "An air-cooled battery system and its thermal management method". Technical Field

[0002] The present invention relates to the technical field of battery temperature control, and particularly relates to a thermal management method and an air-cooled battery system based on the temperature difference of battery cells. Background Art

[0003] In the energy storage field, lithium batteries in groups often use electric boxes as basic units, and multiple electric boxes are stacked to form a battery cluster. A single battery cluster is mostly used for industrial and commercial energy storage, and multiple battery clusters can match the power demand for grid-side energy storage. At the same time, with the increasing popularity of the requirements for high-capacity and high-rate charge and discharge of the system, the heat generated by battery charge and discharge increases, and water cooling gradually replaces air cooling as the selection trend of the thermal management system. A set of water cooling systems are selected for a single battery cluster, and a common set of water cooling systems are selected for multiple battery clusters. In addition to the cold plates of the electric boxes, the water-cooled thermal management system also includes water-cooling units and liquid-cooling pipelines.

[0004] Disadvantages of traditional air-cooled systems in the energy storage field: 1. The energy density is relatively low, which does not match the current market demand for high capacity and high energy density; 2. The IP protection level is relatively low, and moisture and dust are likely to penetrate into the battery system and other electrical systems, having an adverse impact on reliability and even safety performance; 3. Except for air conditioners, most traditional air-cooled systems additionally select fans to increase the air volume of convective heat transfer, resulting in multiple failures and high after-sales maintenance costs.

[0005] Disadvantages of existing liquid-cooled systems in the energy storage field: 1. The entire energy storage system has a high dependence on the water-cooling unit. When the water-cooling unit fails and shuts down, the charge and discharge of the battery system are greatly affected; 2. When a leakage occurs in the water circulation of the thermal management system, the severity is relatively high, and the reliability maintenance cost of the water system in the whole life cycle is relatively high; 3. When the coolant temperature is relatively low, condensate problems are likely to occur in the electric box and pipelines, affecting the insulation withstand voltage of the system. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a thermal management method and an air-cooled battery system based on the temperature difference of battery cells, which are more reliable than existing refrigeration systems.

[0007] A thermal management method based on the temperature difference of battery cells includes the steps of: S1. Control the air conditioner connected to the battery compartment to enter the refrigeration or heating operation strategy according to the highest cell temperature, the lowest cell temperature, a preset refrigeration start threshold, and a preset heating start threshold; S2. Calculate the maximum temperature difference of the battery cells in real time, and adjust the refrigeration stop threshold and the heating stop threshold according to the current operating strategy of the air conditioner, the lowest battery cell temperature, and the highest battery cell temperature, so that the air conditioner system stops refrigeration and heating when the maximum temperature difference of the battery cells exceeds the preset temperature difference threshold.

[0008] To solve the above technical problems, another technical solution adopted by the present invention is: An air-cooled battery system includes a controller, an air conditioner, a battery compartment, and a battery cluster arranged in the battery compartment by stacking air-cooled electric boxes. The battery compartment encloses and wraps the air-cooled electric box, and is provided with a wind guide cover, an air conditioner air outlet connected to the air conditioner, and an air conditioner air return opening. The air output from the air conditioner is evenly distributed to the heat dissipation fin cold plate below the air-cooled electric box through the air conditioner air outlet and the wind guide cover. The battery compartment forms an air-cooled circuit through the air conditioner air outlet, the air conditioner air return opening, and the wind guide cover. The controller is connected to the air conditioner for control, and detects the battery cell temperature of each electric box level in real time, and the implementation includes the steps: S1. Control the air conditioner connected to the battery compartment to enter the refrigeration or heating operation strategy according to the highest battery cell temperature, the lowest battery cell temperature, the preset refrigeration start threshold, and the heating start threshold. S2. Calculate the maximum temperature difference of the battery cells in real time, and adjust the refrigeration stop threshold and the heating stop threshold according to the current operating strategy of the air conditioner, the lowest battery cell temperature, and the highest battery cell temperature, so that the air conditioner system stops refrigeration and heating when the maximum temperature difference of the battery cells exceeds the preset temperature difference threshold.

[0009] The beneficial effects of the present invention are as follows: In a thermal management method and an air-cooled battery system based on the temperature difference of battery cells of the present invention, the battery cells of multiple air-cooled electric box levels are stacked and arranged to form a battery cluster, which is enclosed in a battery compartment to improve the energy density and the IP protection level. An air conditioner air outlet and an air conditioner air return opening are provided for the battery compartment, which are connected to the air conditioner. The air output from the air conditioner is guided to the heat dissipation fin cold plate below the air-cooled electric box through the wind guide cover to dissipate heat from the air-cooled electric box, forming an air-cooled circuit to ensure system heat dissipation. At the same time, considering that due to the low density and heat capacity of air, compared with the inlet and outlet water temperatures of a water-cooled unit, the temperature difference between the inlet and outlet air of the air conditioner is larger under the same heat exchange amount. Therefore, the temperature difference of the battery cells at the electric box level is larger, resulting in a larger temperature difference of the battery cells at the battery cluster level. A corresponding thermal management strategy is matched to control the temperature of the battery cells. Description of the Drawings

[0010] Figure 1 It is a structural diagram of an air-cooled battery system according to an embodiment of the present invention. Figure 2Schematic diagram of air outlet and return air of air conditioner for an air-cooled battery system according to an embodiment of the present invention; Figure 3 Schematic diagram of air guide cover and electrical box of air conditioner for an air-cooled battery system according to an embodiment of the present invention; Figure 4 Flow chart of thermal management method for an air-cooled battery system according to an embodiment of the present invention; Figure 5 Specific process example diagram of thermal management method for an air-cooled battery system according to an embodiment of the present invention; Label description: 1. Air-cooled electrical box; 2. Battery compartment; 3. Air conditioner air outlet; 4. Air conditioner return air inlet; 5. Air guide cover. Specific implementation manner

[0011] To describe in detail the technical content, achieved objectives and effects of the present invention, the following is described in conjunction with the implementation manners and accompanied by the drawings.

[0012] Please refer to Figures 1 to 3 , an air-cooled battery system, including a controller, an air conditioner, a battery compartment, and a battery cluster arranged by stacking air-cooled electrical boxes in the battery compartment; The battery compartment encloses and wraps the air-cooled electrical box, and is provided with an air guide cover, an air conditioner air outlet connected to the air conditioner, and an air conditioner return air inlet; The air outlet air of the air conditioner is evenly distributed to the heat dissipation fin cold plate below the air-cooled electrical box through the air conditioner air outlet and the air guide cover; The battery compartment forms an air-cooled loop through the air conditioner air outlet, the air conditioner return air inlet, and the air guide cover; The controller is connected to the air conditioner for control, and detects the temperature of the battery cells at each electrical box level in real time for thermal management.

[0013] It can be seen from the above description that the beneficial effect of the present invention is that: an air-cooled battery system of the present invention stacks the battery cells at multiple air-cooled electrical box levels to form a battery cluster, which is enclosed in a battery compartment to improve the energy density and IP protection level. An air conditioner air outlet and an air conditioner return air inlet are provided for the battery compartment, which are connected to the air conditioner. The air outlet air of the air conditioner is guided to the heat dissipation fin cold plate below the air-cooled electrical box through the air guide cover to dissipate heat from the air-cooled electrical box, forming an air-cooled loop to ensure system heat dissipation.

[0014] Please refer to Figure 4 and Figure 5 , a thermal management method for an air-cooled battery system, applicable to the thermal management of the above-mentioned air-cooled battery system, including the steps of: S1. Control the air conditioner to enter the cooling or heating operation mode according to the highest battery cell temperature, the lowest battery cell temperature, a preset cooling start threshold, and a preset heating start threshold; S2. Calculate the maximum temperature difference of the battery cells in real time, and adjust the refrigeration stop threshold and the heating stop threshold according to the current operating strategy of the air conditioner, the lowest battery cell temperature, and the highest battery cell temperature, so that the air conditioner system stops refrigerating and heating when the maximum temperature difference of the battery cells exceeds a preset temperature difference threshold.

[0015] As can be seen from the above description, the beneficial effects of the present invention are as follows: A thermal management method for an air-cooled battery system is provided, which is applied to an air-cooled battery system of the present invention. Considering that due to the low density and heat capacity of air, compared with the inlet and outlet water temperatures of a water-cooled unit, the temperature difference between the inlet and outlet air of the air conditioner is larger under the same heat exchange amount, so the temperature difference of the battery cells at the electric box level is larger, resulting in a larger temperature difference of the battery cells at the battery cluster level. The thermal management method for an air-cooled battery system of the present invention adjusts the operating strategy according to the battery cell temperature and adjusts the refrigeration stop threshold based on the temperature difference of the battery cells, so that the air conditioner stops refrigerating when the temperature difference of the battery cells is large, raising the outlet air temperature of the air conditioner, thereby delaying the trend of the temperature difference of the battery cells from amplifying or even reducing the temperature difference of the battery cells. That is, because the set refrigeration stop point is relatively high, it is not easy to trigger refrigeration, while the set point of the internal fan stop is relatively low, so the internal fan circulation mode will be triggered. In this mode, the air conditioner neither refrigerates nor heats, and the air in the battery compartment circulates automatically under the drive of the internal fan of the air conditioner, thereby reducing the battery temperature difference.

[0016] Further, step S1 includes the steps of: S11. Determine whether the highest battery cell temperature is greater than a preset refrigeration start threshold. If so, enter the refrigeration strategy; S12. Determine whether the lowest battery cell temperature is less than a preset heating start threshold. If so, enter the heating strategy.

[0017] As can be seen from the above description, according to the highest and lowest battery cell temperatures, select to enter the refrigeration or heating strategy.

[0018] Further, step S2 includes the steps of: Control the air conditioner to power on; Obtain the preset first refrigeration stop threshold, refrigeration hysteresis, heating stop threshold, heating hysteresis, and internal fan stop threshold under the refrigeration strategy, and control the air conditioner; Judge by calculating the maximum temperature difference of the battery cells in real time. If the maximum temperature difference of the battery cells is greater than a preset temperature difference threshold, increase the first refrigeration stop threshold to a preset second refrigeration stop threshold, and control the air conditioner according to the second refrigeration stop threshold; When the highest battery cell temperature is less than the preset air conditioner power-off temperature under refrigeration, control the air conditioner to power off.

[0019] As described above, in the cooling mode, the air conditioner control parameters corresponding to the preset are obtained to control the air conditioner, and it is continuously determined whether the maximum temperature difference of the battery cells exceeds the preset threshold. If so, it is considered that the temperature difference of the battery cells is too large, and the cooling stop threshold is adjusted, thereby indirectly raising the air outlet temperature of the air conditioner, delaying the change trends of the high-temperature and low-temperature battery cells, and thus delaying the trend of the temperature difference of the battery cells from increasing or even reducing the temperature difference of the battery cells.

[0020] Further, when implementing the heating strategy, step S2 includes the steps of: Controlling the air conditioner to be powered on; Obtaining the preset heating stop threshold, heating dead band, indoor fan stop threshold, cooling stop threshold, and cooling dead band under the heating strategy, and controlling the air conditioner; When the lowest battery cell temperature is greater than the preset heating power-off temperature, controlling the air conditioner to be powered off.

[0021] As described above, the air conditioner control of the heating strategy is performed through the above steps.

[0022] Further, step S1 further includes the steps of: If the highest battery cell temperature is less than the cooling start threshold and the lowest battery cell temperature is greater than the heating start threshold, the maximum temperature difference of the battery cells is continuously calculated. When the maximum temperature difference of the battery cells is greater than the preset temperature difference threshold, enter the temperature difference reduction strategy.

[0023] As described above, when not entering the cooling or heating strategy and the temperature difference of the battery cells is relatively high, the temperature difference reduction strategy is implemented to control the air conditioner.

[0024] Further, when implementing the temperature difference reduction strategy, step S2 includes the steps of: Controlling the air conditioner to be powered on; Obtaining the preset cooling stop threshold, cooling dead band, heating stop threshold, heating dead band, and indoor fan stop threshold under the temperature difference reduction strategy, and controlling the air conditioner; Continuously calculating the maximum temperature difference of the battery cells. When the maximum temperature difference of the battery cells is less than the preset power-off temperature difference threshold, controlling the air conditioner to be powered off.

[0025] As described above, when not entering the cooling or heating strategy and the temperature difference of the battery cells is relatively high, the temperature difference reduction strategy powers on the air conditioner and drives the air to circulate automatically through the indoor fan circulation mode, thereby reducing the battery temperature difference.

[0026] Further, if the highest battery cell temperature is less than the cooling start threshold, the lowest battery cell temperature is greater than the heating start threshold, and the maximum temperature difference of the battery cells is less than the preset temperature difference threshold, the return air temperature of the air conditioner return air outlet is continuously obtained. When the return air temperature is greater than the preset return air temperature threshold, enter the anti-sun exposure strategy.

[0027] As described above, if the temperature of the battery cell does not reach the refrigeration condition, but the return air temperature in the battery compartment exceeds 45°C, it is considered that there is sun exposure, and at this time, the anti-sun exposure control strategy is triggered.

[0028] Furthermore, power on the air conditioner and perform refrigeration; Obtain the preset refrigeration stop threshold, refrigeration dead band, heating stop threshold, heating dead band, and internal fan stop threshold under the anti-sun exposure strategy, and control the air conditioner; Monitor the return air temperature in real time, and when the return air temperature is lower than the preset return air shutdown temperature threshold, control the air conditioner to power off.

[0029] As described above, under the anti-sun exposure strategy, obtain the corresponding control parameters and control the air conditioner to refrigerate to adjust the temperature in the battery compartment.

[0030] An air-cooled battery system and its thermal management method of the present invention are applicable to scenarios where there is a need for an air-cooled battery system.

[0031] Please refer to Figures 1 to 3 , Example 1 of the present invention is: An air-cooled battery system includes a controller, an air conditioner, an air-cooled electrical box 1, and a battery compartment 2; The battery clusters obtained by stacking the air-cooled electrical boxes 1 are arranged in the battery compartment 2; The battery compartment 2 encloses the air-cooled electrical box 1, and is provided with a wind guide cover 5, an air conditioner air outlet 3 connected to the air conditioner, and an air conditioner return air inlet 4; The air conditioner air outlet passes through the air conditioner air outlet 3 and the wind guide cover 5 and is evenly distributed to the heat dissipation fin cold plate below the air-cooled electrical box 1; The battery compartment 2 forms an air-cooled circuit through the air conditioner air outlet 3, the air conditioner return air inlet 4, and the wind guide cover 5.

[0032] As Figure 2 shown in the air conditioner air supply and return air schematic diagram, the air conditioner air supply first enters the battery compartment 2 through the air conditioner air outlet 3, and then is distributed to below each electrical box through the wind guide cover 5. After the air conditioner air supply fully exchanges heat with the heat dissipation fin cold plate of the air-cooled electrical box 1, the return air returns to the air conditioner return air inlet 4 from the upper and lower spaces of the battery compartment 2.

[0033] For the above-mentioned formed air-cooled circuit, heat is generated by the battery, and refrigeration is performed by the air conditioner. The cooling medium is the circulating air in the battery compartment 2, and the circulating air is driven by the internal fan of the air conditioner. As Figure 3Schematic diagram of the air-conditioning air deflector shown. The air output from the air conditioner blows into the air-conditioning air deflector 5 through the air outlet 3 of the air conditioner. Different area air outlets are provided at the outlet of the air-conditioning air deflector 5, and each air outlet faces the heat dissipation fin cold plate of an electric box. Different areas of the air outlets are set to affect the air resistance, so as to design that the air volume of each air outlet remains consistent, and further ensure that the air volume of the air conditioner distributed to each air-cooled electric box 1 in the battery cluster is consistent.

[0034] The controller is connected to the air conditioner in a controlled manner and detects the temperature of the battery cells at each electric box level in real time for thermal management.

[0035] Please refer to Figure 4 and Figure 5 , Embodiment 2 of the present invention is as follows: A thermal management method for an air-cooled battery system, applicable to the thermal management of the above-mentioned air-cooled battery system, includes the steps: S1. Control the air conditioner to enter the cooling or heating operation mode according to the highest battery cell temperature, the lowest battery cell temperature, a preset cooling start threshold, and a preset heating start threshold; Step S1 includes the steps: S11. Judge whether the highest battery cell temperature is greater than the preset cooling start threshold. If so, enter the cooling strategy; S12. Judge whether the lowest battery cell temperature is less than the preset heating start threshold. If so, enter the heating strategy.

[0036] In this embodiment, as Figure 4 shown, when the highest battery cell temperature T max is greater than 30 °C, enter the cooling strategy, and when the lowest battery cell temperature T min is less than 5 °C, enter the heating mode.

[0037] S2. Calculate the maximum temperature difference of the battery cells in real time, and adjust the cooling stop threshold and the heating stop threshold according to the current operation strategy of the air conditioner, the lowest battery cell temperature, and the highest battery cell temperature, so that the air conditioner system stops cooling and heating when the maximum temperature difference of the battery cells exceeds the preset temperature difference threshold.

[0038] When implementing the cooling strategy, step S2 includes the steps: S211. Control the air conditioner to be powered on; S212. Obtain the preset first cooling stop threshold, cooling hysteresis, heating stop threshold, heating hysteresis, and internal fan stop threshold under the cooling strategy, and control the air conditioner; In this embodiment, in the cooling mode, the cooling stop point (i.e., the cooling stop threshold) is 20 °C, the cooling hysteresis is 5 °C, the heating stop point (i.e., the heating stop threshold) is 10 °C, the heating hysteresis is 5 °C, and the internal fan stop point (i.e., the internal fan stop threshold) is 30 °C.

[0039] S213. Calculate the maximum temperature difference of the battery cells in real time for judgment. If the maximum temperature difference of the battery cells is greater than the preset temperature difference threshold, increase the first refrigeration stop threshold to the preset second refrigeration stop threshold, and control the air conditioner according to the second refrigeration stop threshold.

[0040] In this embodiment, if the maximum temperature difference of the battery cells is greater than the preset temperature difference threshold (7°C in this embodiment), increase the refrigeration stop point to 25°C.

[0041] S214. When the highest battery cell temperature is less than the preset refrigeration power-off temperature, control the air conditioner to power off.

[0042] In this embodiment, when the highest battery cell temperature is less than or equal to 25°C, control the air conditioner to power off.

[0043] When executing the heating strategy, step S2 includes the steps: S221. Control the air conditioner to power on; S222. Obtain the preset heating stop threshold, heating hysteresis, internal fan stop threshold, refrigeration stop threshold, and refrigeration hysteresis under the heating strategy, and control the air conditioner.

[0044] In this embodiment, under the heating strategy, the refrigeration stop point is 30°C, the refrigeration hysteresis is 5°C, the heating stop point is 20°C, the heating hysteresis is 5°C, and the internal fan stop point is 0°C.

[0045] S223. When the lowest battery cell temperature is greater than the preset heating power-off temperature, control the air conditioner to power off.

[0046] In this embodiment, when the lowest battery cell temperature is greater than 10°C, control the air conditioner to power off.

[0047] Please refer to Figure 4 , Embodiment 3 of the present invention is: A thermal management method for an air-cooled battery system, different from Embodiment 1 in that step S1 further includes the steps: If the highest battery cell temperature is less than the refrigeration start threshold and the lowest battery cell temperature is greater than the heating start threshold, calculate the maximum temperature difference of the battery cells in real time. When the maximum temperature difference of the battery cells is greater than the preset temperature difference threshold, enter the temperature difference reduction strategy.

[0048] In this embodiment, when the maximum temperature difference of the battery cells is greater than 7°C, enter the temperature difference reduction strategy (or temperature difference reduction mode).

[0049] When executing the temperature difference reduction strategy, step S2 includes the steps: Control the air conditioner to power on; Obtain the preset cooling stop threshold, cooling hysteresis, heating stop threshold, heating hysteresis, and internal fan stop threshold under the temperature difference reduction strategy, and control the air conditioner.

[0050] In this embodiment, under the temperature difference reduction strategy, the cooling stop point is 45°C, the cooling hysteresis is 5°C, the heating stop point is 20°C, the heating hysteresis is 5°C, and the internal fan stop point is 0°C.

[0051] Calculate the maximum temperature difference of the battery cells in real time. When the maximum temperature difference of the battery cells is less than the preset power-off temperature difference threshold, control the air conditioner to power off.

[0052] In this embodiment, calculate the maximum temperature difference of the battery cells in real time. When the maximum temperature difference of the battery cells is less than the power-off temperature difference threshold (4°C in this embodiment), control the air conditioner to power off.

[0053] Please refer to Figure 4 , Embodiment 4 of the present invention is: A thermal management method for an air-cooled battery system, which is different from Embodiment 1 in that step S1 further includes the steps of: If the highest battery cell temperature is less than the cooling start threshold, the lowest battery cell temperature is greater than the heating start threshold, and the maximum temperature difference of the battery cells is less than the preset temperature difference threshold, obtain the return air temperature at the air conditioner return air outlet in real time. When the return air temperature is greater than the preset return air temperature threshold, enter the anti-sun exposure strategy.

[0054] In this embodiment, when the return air temperature is greater than 45°C, enter the anti-sun exposure mode.

[0055] When executing the anti-sun exposure strategy, step S2 includes the steps of: Control the air conditioner to power on; Obtain the preset cooling stop threshold, cooling hysteresis, heating stop threshold, heating hysteresis, and internal fan stop threshold under the anti-sun exposure strategy, and control the air conditioner.

[0056] In this embodiment, in the anti-sun exposure mode, the cooling stop point is 25°C, the cooling hysteresis is 5°C, the heating stop point is 0°C, the heating hysteresis is 5°C, and the internal fan stop point is 30°C.

[0057] Monitor the return air temperature in real time. When the return air temperature is lower than the preset return air shutdown temperature threshold, control the air conditioner to power off.

[0058] In this embodiment, monitor the return air temperature in real time. When the return air temperature is less than or equal to 35°C, control the air conditioner to power off.

[0059] The temperature values involved in the thermal management strategy described in this patent include but are not limited to the specific values described above. The temperature settings related to the battery cells can be within the range of ±10°C, and the temperature settings related to the air conditioner can be within the range of ±20°C.

[0060] In summary, for an air-cooled battery system and its thermal management method provided by the present invention, multiple cells at the air-cooled electric box level are stacked and arranged to form a battery cluster, which is enclosed in a battery compartment to improve the energy density and IP protection level. An air-conditioning air outlet and an air-conditioning air return are provided for the battery compartment, which are connected to the air conditioner. The air-conditioning air outlet is guided to the heat dissipation fin cold plate below the air-cooled electric box through a wind guide cover to dissipate heat from the air-cooled electric box, forming an air-cooled loop to ensure system heat dissipation. At the same time, considering that due to the low density and heat capacity of air, compared with the inlet and outlet water temperatures of a water-cooled unit, the temperature difference between the inlet and outlet air of the air conditioner is larger under the same heat exchange capacity. Therefore, the temperature difference between the cells at the electric box level is larger, resulting in a larger temperature difference between the cells at the battery cluster level. For the thermal management method of the air-cooled battery system of the present invention, the operation strategy is adjusted according to the cell temperature, and the refrigeration stop threshold is adjusted based on the cell temperature difference, so that when the cell temperature difference is large, the air conditioner stops refrigerating, raising the air outlet temperature of the air conditioner, thereby delaying the amplification trend of the cell temperature difference or even reducing the cell temperature difference. That is, because the set refrigeration stop point is relatively high, it is not easy to trigger refrigeration, while the internal fan stop point is set relatively low, so the internal fan circulation mode will be triggered. In this mode, the air conditioner neither refrigerates nor heats, and the air in the battery compartment circulates automatically under the drive of the internal fan of the air conditioner, thereby reducing the battery temperature difference.

[0061] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in the related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A thermal management method based on the temperature difference of battery cells, characterized in that, Including the steps: S1. Control the air conditioner connected to the battery compartment to enter the cooling or heating operation strategy according to the highest cell temperature, the lowest cell temperature, a preset cooling start threshold, and a preset heating start threshold; S2. Calculate the maximum cell temperature difference in real time, and adjust the cooling stop threshold and the heating stop threshold according to the current operation strategy of the air conditioner, the lowest cell temperature, and the highest cell temperature, so that the air conditioner system stops cooling and heating when the maximum cell temperature difference exceeds a preset temperature difference threshold.

2. The thermal management method based on the temperature difference of battery cells according to claim 1, characterized in that Step S1 includes the steps: S11. Determine whether the highest cell temperature is greater than the preset cooling start threshold. If so, enter the cooling strategy; When implementing the cooling strategy, step S2 includes the steps: Control the air conditioner to power on; Obtain the preset first cooling stop threshold, cooling hysteresis, and internal fan stop threshold under the cooling strategy, and control the air conditioner; Calculate the maximum cell temperature difference in real time for judgment. If the maximum cell temperature difference is greater than the preset temperature difference threshold, increase the first cooling stop threshold to the preset second cooling stop threshold, and control the air conditioner according to the second cooling stop threshold; When the highest cell temperature is less than the preset cooling power-off temperature, control the air conditioner to power off.

3. The thermal management method based on the temperature difference of battery cells according to claim 1, wherein Step S1 includes the steps: S12. Determine whether the lowest cell temperature is less than the preset heating start threshold. If so, enter the heating strategy; When implementing the heating strategy, step S2 includes the steps: Control the air conditioner to power on; Obtain the preset heating stop threshold, heating hysteresis, and internal fan stop threshold under the heating strategy, and control the air conditioner; When the lowest cell temperature is greater than the preset heating power-off temperature, control the air conditioner to power off.

4. The thermal management method based on the temperature difference of battery cells according to claim 1, wherein Step S1 further includes the steps: If the highest cell temperature is less than the cooling start threshold and the lowest cell temperature is greater than the heating start threshold, calculate the maximum cell temperature difference in real time. When the maximum cell temperature difference is greater than the preset temperature difference threshold, enter the temperature difference reduction strategy; When implementing the temperature difference reduction strategy, step S2 includes the steps: Control the air conditioner to power on; Obtain the preset cooling stop threshold, cooling hysteresis, heating stop threshold, heating hysteresis, and internal fan stop threshold under the temperature difference reduction strategy, and control the air conditioner; Calculate the maximum cell temperature difference in real time. When the maximum cell temperature difference is less than the preset power-off temperature difference threshold, control the air conditioner to power off.

5. A thermal management method based on the temperature difference of battery cells according to claim 1, characterized in that Step S1 further includes the steps: If the highest cell temperature is less than the cooling start threshold, the lowest cell temperature is greater than the heating start threshold, and the maximum cell temperature difference is less than the preset temperature difference threshold, obtain the return air temperature of the air conditioner return air outlet in real time. When the return air temperature is greater than the preset return air temperature threshold, enter the anti-sun exposure strategy; When implementing the anti-sun exposure strategy, step S2 includes the steps: Control the air conditioner to power on; Obtain the preset cooling stop threshold, cooling hysteresis, heating stop threshold, heating hysteresis, and internal fan stop threshold under the anti-sun exposure strategy, and control the air conditioner; Monitor the return air temperature in real time. When the return air temperature is lower than the preset return air shutdown temperature threshold, control the air conditioner to power off.

6. An air-cooled battery system, characterized in that, It includes a controller, an air conditioner, a battery compartment, and a battery cluster disposed in the battery compartment and obtained by stacking air-cooled electrical boxes. The battery compartment encloses and wraps the air-cooled electrical box, and is provided with a wind guide cover, an air conditioner air outlet connected to the air conditioner, and an air conditioner air return port. The air output from the air conditioner is evenly distributed to the heat dissipation fin cold plate below the air-cooled electrical box through the air conditioner air outlet and the wind guide cover. The battery compartment forms an air-cooled circuit through the air conditioner air outlet, the air conditioner air return port, and the wind guide cover. The controller is connected to the air conditioner for control, and real-time detects the temperature of the battery cells at each electrical box level, and the implementation includes the steps of: S1. Control the air conditioner connected to the battery compartment to enter the cooling or heating operation strategy according to the highest battery cell temperature, the lowest battery cell temperature, a preset cooling start threshold, and a preset heating start threshold. S2. Real-time calculate the maximum temperature difference of the battery cells, and adjust the cooling stop threshold and the heating stop threshold according to the current operation strategy of the air conditioner, the lowest battery cell temperature, and the highest battery cell temperature, so that the air conditioner system stops cooling and heating when the maximum temperature difference of the battery cells exceeds a preset temperature difference threshold.

7. The air-cooled battery system according to claim 6, wherein The specific way that the air output from the air conditioner is evenly distributed to the heat dissipation fin cold plate below the air-cooled electrical box through the air conditioner air outlet and the wind guide cover is: The air output from the air conditioner is blown into the wind guide cover through the air conditioner air outlet, and each air outlet of the wind guide cover faces the heat dissipation fin cold plate of an electrical box, and the air output volume is the same.

8. The air-cooled battery system according to claim 6, characterized in that, Step S1 includes the steps of: [[ID=1*]]S11. Judge whether the highest battery cell temperature is greater than a preset cooling start threshold. If so, enter the cooling strategy. S12. Judge whether the lowest battery cell temperature is less than a preset heating start threshold. If so, enter the heating strategy. When implementing the cooling strategy, step S2 includes the steps of: Control the air conditioner to be powered on. Obtain a preset first cooling stop threshold, a cooling hysteresis, and an internal fan stop threshold under the cooling strategy, and control the air conditioner. Real-time calculate and judge the maximum temperature difference of the battery cells. If the maximum temperature difference of the battery cells is greater than a preset temperature difference threshold, increase the first cooling stop threshold to a preset second cooling stop threshold, and control the air conditioner according to the second cooling stop threshold. When the highest battery cell temperature is less than a preset cooling power-off temperature, control the air conditioner to be powered off. When implementing the heating strategy, step S2 includes the steps of: Control the air conditioner to be powered on. Obtain a preset heating stop threshold, a heating hysteresis, and an internal fan stop threshold under the heating strategy, and control the air conditioner. When the lowest battery cell temperature is greater than a preset heating power-off temperature, control the air conditioner to be powered off.

9. The air-cooled battery system according to claim 6, characterized in that, Step S1 further includes the steps of: If the highest battery cell temperature is less than the cooling start threshold, and the lowest battery cell temperature is greater than the heating start threshold, then real-time calculate the maximum temperature difference of the battery cells. When the maximum temperature difference of the battery cells is greater than a preset temperature difference threshold, enter the temperature difference reduction strategy. When implementing the temperature difference reduction strategy, step S2 includes the steps of: Control the air conditioner to be powered on. Obtain a preset cooling stop threshold, a cooling hysteresis, a heating stop threshold, a heating hysteresis, and an internal fan stop threshold under the temperature difference reduction strategy, and control the air conditioner. Calculate the maximum temperature difference of the battery cell in real time. When the maximum temperature difference of the battery cell is less than the preset power-off temperature difference threshold, control the air conditioner to power off.

10. The air-cooled battery system according to claim 6, characterized in that, Step S1 further includes the step of: If the highest battery cell temperature is less than the refrigeration start threshold, the lowest battery cell temperature is greater than the heating start threshold, and the maximum temperature difference of the battery cell is less than the preset temperature difference threshold, obtain the return air temperature of the air conditioner return air outlet in real time. When the return air temperature is greater than the preset return air temperature threshold, enter the anti-sun exposure strategy; When executing the anti-sun exposure strategy, step S2 includes the steps of: Control the air conditioner to power on; Obtain the preset refrigeration stop threshold, refrigeration hysteresis, heating stop threshold, heating hysteresis and internal fan stop threshold under the anti-sun exposure strategy, and control the air conditioner; Monitor the return air temperature in real time. When the return air temperature is lower than the preset return air shutdown temperature threshold, control the air conditioner to power off.

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