A power battery module dot matrix uniform heating cooling plate structure and a thermal management control method

Abstract

This invention relates to the field of thermal management technology for power batteries in new energy vehicles, specifically disclosing a dot-matrix type heat dissipation cooling plate structure for a power battery module and a thermal management control method. The structure includes 64 18650 cells arranged in an 8×8 rectangular dot matrix, 64 flower-shaped heat-conducting frames, two upper and lower aluminum liquid cooling plates, two upper and lower customized thermally conductive silicone layers, temperature sensors, and a main control unit. Each of the upper and lower liquid cooling plates has four maple leaf-shaped symmetrical flow channels inside, with coolant flowing in from the four corners and symmetrically out from the edges. The flower-shaped heat-conducting frames are fitted onto the positive electrode of the cells to achieve series-parallel connection and axial heat conduction. The thermally conductive silicone layers are attached to the top and bottom of the cells. Temperature sensors are located at the center and top of the cells and communicate with the main control unit. A thermal management control method adapted to this structure is also disclosed. By collecting temperature data, calculating the average temperature, maximum temperature difference, and internal temperature difference of a single cell, and comparing these with preset thresholds, the coolant flow rate is dynamically adjusted. This invention achieves bidirectional high-efficiency heat conduction in the battery module, reduces the temperature difference between the axial direction of the cell and the circumferential direction of the module, improves temperature uniformity and thermal management response speed, effectively prevents thermal runaway, and avoids energy waste due to excessive cooling.

Description

Technical Field

[0001] This invention relates to the field of thermal management technology for power batteries in new energy vehicles, and more specifically, to a dot matrix heat dissipation cooling plate structure for 18650 cylindrical battery modules and its thermal management control method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the market has placed higher demands on the range and charging speed of electric vehicles. Consequently, the energy density and charge / discharge rate of power batteries are constantly increasing, leading to the generation of a large amount of heat during charging, discharging, and operation. If this heat cannot be dissipated in a timely and even manner, it will cause uneven temperature distribution within the battery module. Localized overheating will accelerate the aging of the battery's positive and negative electrode materials, reduce the battery's cycle life, and in severe cases, even trigger thermal runaway, causing safety accidents such as fires and explosions, thus restricting the safe application of power batteries.

[0003] Current power battery thermal management solutions primarily employ bottom / side liquid cooling plates / pipe cooling or phase change material (PCM) coupling. However, these solutions have significant drawbacks: bottom / side liquid cooling plates / pipe cooling can only conduct heat radially or circumferentially from the cell, making it difficult to handle the large temperature difference along the cell's axial (height) direction during high-rate charging and discharging. This results in a significant temperature difference between the top and bottom of the cell, leading to poor thermal management. Furthermore, PCMs have low heat transfer efficiency, only temporarily storing heat and failing to dissipate it promptly, thus failing to meet the heat dissipation requirements of high-energy-density batteries. In addition, traditional liquid cooling plates often feature simple long rectangular or serpentine coolant channels, resulting in high flow resistance, uneven coolant flow distribution, and delayed cooling response, hindering rapid and uniform cooling of each cell within the module.

[0004] For the thermal management of 18650 cylindrical batteries, some solutions combine phase change materials (PCM) for temperature control. However, PCM has the problems of large volume and bulky module, as well as the risk of PCM leakage. At the same time, the thermal conductivity of PCM is limited, and the heat generated by the battery module is easy to accumulate and cannot be dissipated in time, making it difficult to adapt to high-rate charging and discharging scenarios.

[0005] Therefore, how to achieve uniform cooling of the cell axis and module circumference by optimizing the flow channel structure of the cooling plate and the intelligent control strategy of thermal management, and improve the response speed and temperature control accuracy of the battery module thermal management, has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the technical defects of existing power battery thermal management solutions, such as uneven temperature, slow cooling response, and low heat exchange efficiency, and to provide a dot matrix heat dissipation cooling plate structure and thermal management control method for power battery modules. This enables efficient and uniform cooling and intelligent and precise temperature control of the battery modules, reduces the axial temperature difference of the cells and the circumferential temperature difference of the modules, and improves thermal management safety and energy efficiency.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: On one hand, a dot-matrix heat dissipation cooling plate structure for a power battery module is provided, including a battery module, an upper liquid cooling plate, a lower liquid cooling plate, an upper thermally conductive silicone layer, a lower thermally conductive silicone layer, a flower-shaped heat conduction frame, a temperature sensor, and a main control unit; the battery module consists of 64 18650 power batteries, and the 64 18650 cells are arranged in an 8×8 pattern. The battery module is arranged in a rectangular matrix pattern. The upper thermally conductive silicone layer is attached to the top of the battery module, and the upper liquid cooling plate is attached to the side of the upper thermally conductive silicone layer near the top of the battery cell. The lower thermally conductive silicone layer is attached to the bottom of the battery module, and the lower liquid cooling plate is attached to the side of the lower thermally conductive silicone layer near the bottom of the battery cell, forming a double-sided liquid-cooled heat exchange structure. Both the upper and lower liquid cooling plates are made of aluminum with a thermal conductivity of 202.4 W / (m·K). Each plate has four maple leaf-shaped flow channels, which are symmetrically distributed to ensure that the flow channels traverse the projection area of ​​each battery cell in a two-dimensional plane. The coolant inlets of the maple leaf-shaped flow channels are respectively located at the four upper diagonal points of the liquid cooling plate. The coolant is injected synchronously from the four corners, flows along a preset planned path, covers the corresponding positions of all battery cells, and then flows out symmetrically from the outlet at the edge of the liquid cooling plate. The flower-shaped heat conduction frame is 64 Each cell is individually fitted onto the positive electrode of the battery cell to achieve series-parallel connection and axial heat conduction. Two temperature sensors are arranged on the surface of each battery cell, located at the center and top of the cell, respectively. The data acquisition frequency of the temperature sensors is 1Hz, and all temperature sensors are connected to the main control unit. The main control unit adjusts the flow rate of the coolant entering the upper and lower liquid cooling plates in real time according to the received temperature data to maintain the battery module operating within the optimal temperature range.

[0008] As a preferred embodiment of the present invention, both the upper and lower thermally conductive silicone layers are integrally molded into specific shapes. The upper thermally conductive silicone layer is 4mm thick and has a circular hole adapted to the battery cell, with a diameter of 7mm and a depth of 1.5mm. The lower thermally conductive silicone layer is 5mm thick, with a circular hole having a diameter of 18mm and a depth of 4mm. The thermal conductivity of both the upper and lower thermally conductive silicone layers is 3W / (m·K), achieving efficient heat conduction between the battery cell and the liquid cooling plate, while also serving as a buffer and insulation. The flower-shaped heat conduction frame has a four-petal flower structure, made of copper-nickel alloy, with a thermal conductivity of 65W / (m·K). The four petals of the flower-shaped heat conduction frame extend outwards, serving a dual purpose: firstly, to achieve series and parallel electrical connections between the battery cells within the battery module; and secondly, to promptly dissipate the heat generated axially by the battery cells, achieving efficient thermal management in conjunction with the liquid cooling plate. The temperature sensor is a thin-film platinum resistance temperature sensor, and the collected temperature signal is transmitted to the main control unit via a CAN bus, ensuring the real-time performance and stability of data transmission.

[0009] On the other hand, a thermal management control method using the above structure includes the following steps: S1. Temperature data acquisition: The temperature data of the battery cells is acquired in real time at a frequency of 1Hz by thin-film platinum resistance temperature sensors deployed at the center and top of each battery cell. The sensors transmit the acquired temperature signals to the main control unit via the CAN bus. S2. Temperature difference calculation: The main control unit receives temperature data transmitted by the temperature sensor and calculates the overall average temperature of the battery module, the maximum temperature difference between different cells, and the internal temperature difference between the center and the top of a single cell based on the temperature data. S3. Threshold comparison: The internal temperature difference of a single cell and the maximum temperature difference between different cells calculated in step S2 are compared with the preset safety thresholds built into the main control unit. The preset safety thresholds include a first threshold of 3°C and a second threshold of 5°C. S4. Dynamic flow regulation: If the internal temperature difference of any single cell exceeds the first threshold, or the maximum temperature difference between different cells exceeds the second threshold, the main control unit dynamically adjusts the coolant inlet flow rate according to the temperature difference position until all temperature difference values ​​fall back to within the preset safety threshold. Specifically, when the temperature difference between the center and the top of a single cell exceeds 3°C, the main control unit increases the coolant flow rate in the corresponding liquid cooling plate area of ​​that cell; when the maximum temperature difference between different cells exceeds 5°C, the main control unit adjusts the overall coolant flow distribution ratio of the liquid cooling plate.

[0010] As a preferred technical solution of the present invention, the optimal operating temperature range of the battery module built into the main control unit is 20℃-40℃. When the car starts and the battery begins to work, the main control unit starts the cooling circulation pump and supplies liquid to the coolant inlets at the four corners of the liquid cooling plate at an initial flow rate v0 for routine thermal management. When the average temperature of the battery module is detected to be close to 40℃, the initial flow rate is increased. If any temperature sensor detects that the cell temperature exceeds 50℃, the main control unit immediately triggers the highest flow rate of the coolant to enhance heat exchange and reports a temperature abnormality signal to the vehicle controller to prevent thermal runaway.

[0011] After adopting the above technical solution, the beneficial effects of the present invention are: The upper and lower double-sided dot matrix liquid cooling plate structure, combined with a customized thermally conductive silicone layer, enables bidirectional heat conduction between the upper and lower parts of the battery cell. The flower-shaped heat conduction frame further enhances the axial heat conduction of the battery cell, effectively reducing the axial temperature difference between the top and middle parts of the battery cell. The maple leaf-shaped symmetrical flow channel runs through all the projected areas of the battery cell, and the coolant flow is evenly distributed, solving the problem of uneven circumferential temperature of the module and making the temperature distribution inside the battery cell and the entire module more uniform.

[0012] Coolant is injected simultaneously from the four corners of the liquid cooling plate and flows along the maple leaf-shaped flow channel, which greatly shortens the path time for the coolant to reach the farthest cell of the module. It can quickly cover all cells and achieve rapid cooling of the battery module, effectively coping with the high heat generation scenario of high-rate charging and discharging. The flow channel design also reduces flow resistance and improves the overall heat exchange efficiency.

[0013] Dual temperature sensors are arranged at the center and top of each cell. Combined with 1Hz high-frequency data acquisition, the main control unit can monitor the temperature gradient inside the cell and the overall temperature distribution of the module in real time and accurately. By preset temperature difference thresholds and temperature ranges, the flow rate of the coolant can be dynamically adjusted in a differentiated manner. This can prevent thermal runaway in a timely manner and avoid energy waste caused by over-cooling, thus taking into account both the safety and energy saving of thermal management.

[0014] Each component adopts a modular, dot-matrix design. The flower-shaped heat-conducting frame integrates electrical connection and heat conduction functions. The heat-conducting silicone layer is a mold-customized structure that fits the battery cell and liquid cooling plate. The overall structure is compact, without bulky phase change materials, and has a low risk of leakage. It is compatible with the standardized design of 18650 cylindrical battery modules, which facilitates the integration and application of power batteries for new energy vehicles. Attached Figure Description

[0015] Figure 1 This is an overall assembly structure diagram of the dot matrix battery module with dual liquid cooling thermal management at the top and bottom, according to the present invention.

[0016] Figure 2 This is a schematic diagram of the coolant flow path within the liquid cooling plate channel of the present invention.

[0017] Figure 3 A customized thermally conductive silicone layer structure diagram is provided for this invention to adapt to the bonding requirements of the battery cell and the liquid cooling plate, thereby achieving efficient heat conduction.

[0018] Figure 4 A comparison of the temperature distribution cloud maps of the three-dimensional battery module under three cooling methods.

[0019] Figure 5 A comparison of cross-sectional temperature distribution cloud maps of the battery module under three cooling methods.

[0020] Figure 6 Comparison of temperature distribution cloud maps in the longitudinal section of the battery module under three cooling methods.

[0021] Figure 7 Abnormal temperature and speed regulation cloud map of battery cell. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0023] Example 1: Dot-matrix heat dissipation cooling plate structure for power battery module This embodiment provides a dot-matrix heat dissipation cooling plate structure for a power battery module, as shown in Figure 1. It includes a battery module composed of 64 18650 cells, upper and lower liquid cooling plates, an upper thermally conductive silicone layer, a lower thermally conductive silicone layer, 64 flower-shaped heat conduction brackets, 128 thin-film platinum resistance temperature sensors, and a main control unit. The 64 18650 cells are arranged in an 8×8 rectangular dot matrix. The flower-shaped heat conduction brackets are correspondingly fitted onto the positive electrode of the cells. The brackets are four-petaled copper-nickel alloy structures with a thermal conductivity of 65 W / (m·K), realizing the series-parallel connection and axial heat conduction of the cells.

[0024] The upper thermally conductive silicone layer is attached to the top of the battery module, with a thickness of 4mm and a circular hole diameter of 7mm and a depth of 1.5mm. The lower thermally conductive silicone layer is attached to the bottom of the battery module, with a thickness of 5mm and a circular hole diameter of 18mm and a depth of 4mm. The thermal conductivity of both the upper and lower thermally conductive silicone layers is 3W / (m·K), and they are integrally molded structures. The upper liquid cooling plate is attached to the outside of the upper thermally conductive silicone layer, and the lower liquid cooling plate is attached to the outside of the lower thermally conductive silicone layer. Both are made of aluminum and have a thermal conductivity of 202.4W / (m·K). As shown in Figure 2, the upper and lower liquid cooling plates each have four maple leaf-shaped symmetrical flow channels inside. Coolant inlets A, B, C, and D are located at the four upper diagonal points of the liquid cooling plate. The coolant flows from the four corners to the middle battery cell of the module, and then flows out symmetrically from the edge of the liquid cooling plate along the flow channels, which traverse the projection area of ​​all battery cells.

[0025] Two temperature sensors are deployed on the surface of each cell, located at the center and top of the cell respectively. The sensors collect data at a frequency of 1 Hz. All sensors communicate with the main control unit via a CAN bus. The main control unit can receive temperature data in real time and adjust the coolant flow rate.

[0026] Example 2 Thermal Management Control Method This embodiment provides a thermal management control method applied to the dot-matrix heat dissipation cooling plate structure of the power battery module described in Embodiment 1. This method achieves precise temperature control of the battery module through temperature acquisition, real-time temperature difference calculation, and dynamic flow regulation, ensuring its safe and efficient operation within the optimal temperature range. Specifically, it includes the following steps: S1: Temperature Data Acquisition A thin-film platinum resistance temperature sensor is mounted on the central area of ​​the cylindrical surface and the upper area near the positive electrode of each 18650 cell, totaling 128 sensors. All sensors synchronously collect temperature data at a fixed frequency of 1 Hz and transmit the temperature signals to the main control unit in real time via the CAN bus. This acquisition frequency enables timely capture of temperature changes under dynamic battery conditions, providing a data basis for rapid response.

[0027] S2: Calculation of Temperature Difference and State Parameters After receiving all temperature sensor data, the main control unit performs the following calculations: Average temperature of battery module , where n is the total number of sensors, and Ti is the temperature value of the i-th sensor.

[0028] Temperature difference inside a single cell Where j=1,2,⋯,64 is the cell number, subscript o indicates the upper part of the cell, and m indicates the middle part of the cell.

[0029] Maximum temperature difference between cells within the module ,in and These are the temperatures at two measuring points of the j-th cell.

[0030] Maximum single-cell temperature .

[0031] S3: Threshold Comparison and State Determination The main control unit has the following built-in preset thresholds and operating ranges: Optimal operating temperature range for the battery: 20℃ – 40℃; First threshold for internal temperature difference in a single battery cell: ; Second threshold for maximum temperature difference between cells within the module: ; Overheat protection threshold: .

[0032] The parameters calculated in step S2 are compared with the above thresholds one by one to determine the current thermal management requirement level: ① Normal state: the average temperature is below 40℃ and all temperature differences are within the threshold; ② Local overheating state: there is a temperature difference ≥ 3℃ inside a certain cell, or the temperature of a certain cell exceeds 40℃ but does not reach 50℃; ③ Overall excessive temperature difference state: the maximum temperature difference between cells in the module is ≥ 5℃; ④ Thermal runaway warning state: the temperature of any cell is ≥ 50℃.

[0033] S4: Dynamic Flow Regulation Strategy Based on the status determination results, the main control unit performs differentiated adjustment of the flow distribution to the cooling circulation pump and the four corner inlets of the liquid cooling plate. The four inlets (A, B, C, D) of the liquid cooling plate correspond to the starting areas of the four maple leaf-shaped flow channels. By adjusting the opening of the electric proportional valve of each inlet, the coolant flow in different areas can be controlled independently.

[0034] ① Normal state: When the car is started, if the average temperature is below 40℃ and the temperature difference does not exceed the standard, the main control unit starts the cooling circulation pump and supplies liquid evenly to the four corner inlets at an initial flow rate v0 to maintain the module temperature stability.

[0035] ② Local Overheating: If a temperature difference ≥ 3℃ is detected inside a battery cell, or if the temperature of a battery cell exceeds 40℃ but does not reach 50℃, the main control unit first locates the liquid cooling plate area to which the battery cell belongs (determining which inlet area it corresponds to based on the battery cell's position in the 8×8 dot matrix). The opening of the proportional flow valve at the corresponding inlet of that area is increased, raising the local flow velocity to 1.2-1.5v0 to enhance forced heat transfer in that area. Simultaneously, the inlet flow velocity of other areas is maintained at v0 to avoid overcooling. After adjustment, the temperature difference of the battery cell is continuously monitored. If the temperature difference does not decrease after 3 sampling cycles, the local flow velocity is increased in increments of 0.1v0 until the temperature difference drops below 3℃.

[0036] ③ Excessive overall temperature difference: If the maximum temperature difference between cells within the module is ≥ 5℃, it indicates uneven flow distribution. The main control unit recalculates the average temperature of each area, increases the inlet flow rate for areas with higher temperatures, appropriately reduces the flow rate for areas with lower temperatures, and reassesses the temperature difference. Through iterative adjustments, the maximum temperature difference is reduced to within 5℃.

[0037] ④ Thermal runaway warning status: Once the temperature of any sensor is ≥ 50℃, the main control unit will immediately adjust the cooling pump to the highest flow rate, fully open all inlet proportional valves, and urgently cool down the vehicle with maximum heat exchange capacity. At the same time, it will send a temperature abnormality alarm signal to the vehicle controller through the CAN bus, and may also link the vehicle to limit power or activate other safety measures.

[0038] To verify the effectiveness of the structure and control method of this invention, the temperature distribution of the battery module under three thermal management schemes was compared using ANSYS Fluent 2025 simulation software. Option A: Natural cooling; Option B: Cooling only with a single-sided liquid cooling plate at the bottom; Option C: Top and bottom double-sided dot matrix liquid cooling plate combined with intelligent control.

[0039] Simulation conditions are set as follows: the battery module is continuously discharged at a 3C rate, the ambient temperature is 35℃, and the initial temperature is 35℃. Scheme C uses the control method described in this embodiment, with an initial flow rate v0 = 1 m / s. Figure 4 , Figure 5 , Figure 6 The three-dimensional temperature distribution cloud maps, cross-sectional temperature distribution cloud maps, and longitudinal temperature distribution cloud maps of the battery module are shown for three different schemes.

[0040] Figure 4 (a) Under natural cooling, the battery module temperature reached 61.4℃, and the central area of ​​the module cell was red-hot, with a temperature significantly higher than that of the cell periphery. Figure 4 (b) With only a liquid cooling plate added to the bottom of the module, the temperature is relatively low at 26.4℃. The temperature gradually increases from bottom to top, with a maximum temperature difference of 5.41℃. The axial temperature difference is significant. Figure 4 In (c), the color of the entire module is relatively uniform, and the maximum temperature difference is 2.4℃.

[0041] Figure 5 In (a), the temperature at the center of the cross-section is significantly higher than that at the edge; Figure 5 (b) The temperature along the diagonal of the cross section of the battery module is lower than the temperature of the edge cells, mainly due to the maple leaf-shaped flow channel design in the liquid cooling plate. Figure 5 (c) has a uniform temperature distribution in the cross section, with the temperature at the center of each cell being significantly higher than that at the edge, and the maximum temperature difference being only 0.17℃.

[0042] Figure 6 In the longitudinal profile temperature distribution, (a) the maximum temperature of the battery cell under natural cooling is as high as 61.45℃, which is far higher than the safe temperature of the battery cell; (b) there is an obvious temperature gradient in the axial direction when liquid cooling plate is added at the bottom, with a maximum temperature of 6.76℃; (c) liquid cooling plates are arranged at both the top and bottom, and the maximum axial temperature is reduced to 3.13℃, which reduces the axial temperature difference of the battery cell.

[0043] Simulation results show that the structure and control method of this invention reduce the maximum temperature difference of the module to 5℃ and the axial temperature difference of the battery cell to about 3℃. Furthermore, due to the use of dynamic frequency adjustment, Figure 7Simulation results show that when a cell experiences an abnormality (such as cell aging or excessive power due to an internal short circuit), the corresponding flow channel automatically adjusts to increase the flow rate, which can rapidly reduce the cell temperature to a safe range, effectively preventing thermal runaway and avoiding energy loss caused by excessive cooling. Therefore, this invention achieves efficient and uniform cooling and intelligent temperature control of the battery module, possessing outstanding substantive features and significant progress.

Claims

1. A power battery module dot matrix uniform heating cooling plate structure, comprising 64 18650 battery cells arranged in a rectangular dot matrix, 64 flower-shaped heat-conducting frames, an upper and a lower liquid cooling plate, an upper and a lower heat-conducting silica gel layer, a temperature sensor and a main control unit, characterized in that: The upper heat-conducting silica gel layer is attached to the top of the battery module, and the upper liquid cooling plate is attached to one side of the upper heat-conducting silica gel layer near the top of the battery cell. The lower heat-conducting silica gel layer is attached to the bottom of the battery module, and the lower liquid cooling plate is attached to one side of the lower heat-conducting silica gel layer near the bottom of the battery cell, forming a heat exchange structure with double-sided liquid cooling. The upper liquid cooling plate and the lower liquid cooling plate are each provided with four maple leaf-shaped flow channels. The material of the liquid cooling plate is aluminum, and its thermal conductivity is 202.4 W / (m·K). The power battery module dot matrix type uniform heating cooling plate structure is characterized in that: the planning path of the dot matrix type flow channel is symmetrically distributed in a maple leaf shape. The cooling liquid flows into the innermost battery cell of the battery module from the four corners, and then flows out from the edge battery cells of the battery module in a preset flow channel symmetrically.

2. The power battery module dot-matrix uniform heating cooling plate structure according to claim 1, characterized in that: The top and bottom of the battery cell are attached with a heat-conducting silica gel layer. The heat-conducting silica gel is formed into a specific shape in a mold. The thickness of the upper heat-conducting silica gel layer is 4 mm, the diameter of the circular hole is 7 mm, and the depth is 1.5 mm. The thickness of the lower heat-conducting silica gel layer is 5 mm, the diameter of the circular hole is 18 mm, and the depth is 4 mm. The thermal conductivities of the heat-conducting silica gel layers are both 3 W / (m·K).

3. The flower-shaped heat-conducting frame according to claim 1 is a four-petal flower shape that is sleeved on the positive electrode of the battery cell. The four petals are respectively extended outward. The material is copper-nickel alloy, and the thermal conductivities are both 65 W / (m·K). The function of the flower-shaped heat-conducting frame is to connect the battery cells in series and parallel, and to timely conduct the axial temperature of the battery cell to achieve efficient thermal management.

4. The cooling liquid inlets of the dot matrix type flow channel are respectively arranged at the four upper parts of the liquid cooling plate. The surface of each battery cell monomer is provided with two temperature sensors, which are respectively located at the center and the upper part of the battery cell monomer. The data acquisition frequency of the temperature sensor is 1 Hz. All the temperature sensors are in communication connection with the main control unit. The main control unit adjusts the inlet flow rate of the cooling liquid in real time according to the received temperature data.

5. A thermal management control method applied to the structure of claims 1-4, characterized by, The steps include: S1, acquiring temperature data in real time at a frequency of 1 Hz through the temperature sensors distributed at the center and the upper part of each battery cell; S2, the main control unit receives the temperature data and calculates the average temperature, the maximum temperature difference and the internal temperature difference of the battery module; S3, comparing the calculated temperature difference value with the preset safety threshold; S4, if any maximum temperature or temperature difference value exceeds the preset threshold, the main control unit dynamically adjusts the inlet flow rate of the cooling liquid until the temperature difference falls within the threshold.

6. The thermal management control method of claim 5, wherein, In step S4, when the temperature difference between the center and the upper part of a single battery cell exceeds the first threshold value 3℃, the main control unit increases the flow rate of the cooling liquid in the corresponding liquid cooling plate area; when the maximum temperature difference between different battery cells exceeds the second threshold value 5℃, the main control unit adjusts the overall flow distribution ratio.

7. The thermal management control method of claims 5 and 6, wherein: The best working temperature range of the battery module built-in main control unit is 20℃-40℃. When the average temperature of the battery module is close to 40℃, the main control unit starts the cooling circulating pump and supplies the cooling liquid to the cooling liquid inlets of the four corners of the liquid cooling plate at the initial flow rate. If any temperature sensor monitors that the temperature of the battery cell exceeds 50℃, the main control unit immediately triggers the highest flow rate gear of the cooling liquid and reports the temperature abnormal signal to the vehicle controller.

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