Power battery module collaborative thermal management device with composite pin-fin structure and control method

Abstract

The invention discloses a collaborative thermal management device of a power battery module with a composite pin-fin structure and a control method. The device comprises a round-fin air cooling plate (1), a honeycomb buffer layer (2), a shell (3), a lower cover plate (4) and a cooling liquid pipeline (5). A cooling layer and a battery layer are stacked in the device in a stacking mode, and a natural cooling layer, the battery layer, a liquid cooling layer and a phase change cooling layer are adopted for multi-layer composite synergistic thermal management. The natural cooling layer and the phase change cooling layer are passively cooled at the early stage of battery heating, the liquid cooling layer is in contact with the two battery layers through the maximum surface, and inlet conditions are controlled through the temperature control module, so that the batteries are cooled and preheated. The temperature control module monitors the battery temperature Tbat through the temperature sensor and adjusts the cooling liquid temperature Tin and the flow velocity Vin in real time according to the Tbat, and the temperature sensor and the smoke sensor in the device give an alarm in advance when thermal runaway possibly occurs. The device solves the problems of dynamic thermal management, thermal runaway early warning and collision buffering of the battery module.

Description

Technical Field

[0001] The present invention relates to a power battery module collaborative thermal management device and a control method with a composite pin-fin structure, belonging to the technical field of power battery thermal management. Background Art

[0002] With the goal of carbon peak and carbon neutrality, lithium-ion batteries have become the mainstream power source for new energy vehicles due to their no memory effect and low self-discharge rate. However, new energy vehicle fires caused by thermal and mechanical abuse of high energy density power batteries have also attracted much attention from the industry and society.

[0003] As one of the core components of the three-electric system of new energy vehicles, the power battery is inseparable from the power and safety performance of the entire vehicle. Its power characteristics are easily affected by temperature. The power battery is exposed to a high temperature environment of 40°C in summer or a low temperature environment of -10°C in winter for a long time, which has an irreversible impact on its health status, and it is more obvious during high-rate fast charging.

[0004] The existing power battery thermal management technologies mainly include: air cooling and PTC air heating with gas as the medium, composite phase change cooling and heat pipe cooling with phase change materials as the medium, electric heating film heating, and liquid cooling and water PTC heating with liquid as the medium. Among them, gas medium is common in low-end models due to its low thermal conductivity and low cost, and is also seen in coupling with other technologies for collaborative thermal management; phase change materials have outstanding temperature averaging performance but are not easy to package, and are usually used in coupling; heat pipes have the highest thermal conductivity, but are currently less used due to their high cost; electric heating film heating is often used in oil-to-electric platforms, but is rarely used due to its poor temperature uniformity and low temperature rise rate; liquid media have high thermal conductivity, but poor temperature uniformity, and using them in extremely high and low temperature scenarios will increase battery inconsistency. When used in coupling with phase change materials, the thermal management system can have both high thermal conductivity and high temperature averaging performance.

[0005] During liquid cooling, the active transport of the medium essentially consumes the energy of the power battery. Considering that the actual use scenarios of automobiles are relatively complex, the operating temperature of the power battery and the ambient temperature are quite different in winter and summer. In order to save the power consumption of the water pump, PTC and Chiller, it is necessary to design a control strategy for the coolant inlet conditions so that the coolant inlet temperature and inlet flow rate need to be adjusted in real time according to the battery temperature to reduce the power consumption of accessories. The step control strategy, linear parameter control strategy and PID control strategy are commonly used in thermal management system control. The step control strategy control process is staged constant parameter control. The control process is too cumbersome and cannot cope with the dynamic temperature changes of the power battery. The PID control strategy has cumbersome early parameter adjustment. The linear parameter control strategy can use temperature as input to make the coolant inlet conditions change linearly with temperature. The control logic is simple and easy to implement.

[0006] The problem of mechanical abuse of power batteries cannot be avoided during use. By configuring the corresponding buffer layer to reduce the impact during collision, it can effectively ensure the mechanical damage of power batteries in most scenarios. Power battery collision protection is often achieved through a multi-layer combination of vehicle structure protection, battery pack shell protection, and battery cell structure accessory protection. Among them, the protection of the power battery pack itself is particularly important. Wrapping the battery with a stable anti-collision layer can effectively protect the battery. Summary of the invention

[0007] The purpose of the present invention is to solve the problems of traditional power batteries in air cooling and composite phase change thermal management using phase change materials as the medium, and to propose a power battery module collaborative thermal management device and control method with a composite pin-fin structure.

[0008] The technical solution implemented by the present invention is as follows: a composite pin-fin structure power battery module collaborative thermal management device, including an outer shell and a lower cover plate, and also including a round-fin air-cooled plate, a first lithium-ion battery layer, a second lithium-ion battery layer, a liquid-cooled upper cover plate, a liquid-cooled shell, a thermally conductive silicone pad, an outer fin-type phase change upper cover plate, a composite phase change material, an embedded fin-type phase change lower cover plate and an oblique-fin liquid cooling plate; the above-mentioned plates and layers are horizontally installed one by one in a container formed by the outer shell and the lower cover plate.

[0009] The first lithium-ion battery layer and the second lithium-ion battery layer each include 16 identical square lithium-ion battery cells connected in series; the first lithium-ion battery layer and the second lithium-ion battery layer are connected in parallel to form a battery module; the lithium-ion battery cells are separated by partitions, the partitions are epoxy boards, and 14 temperature sensors are arranged on the sides of the lithium-ion battery cells; the 16 lithium-ion batteries in each layer are divided into two groups side by side, and a smoke sensor and a T-shaped nylon water cooling channel are arranged between the two groups of lithium-ion battery cells; the lithium-ion batteries are connected by copper bars, and the copper bars are installed on both sides of the upper and lower ears of each battery cell, and the copper bars are attached to the T-shaped nylon water cooling channel, and a U-shaped coolant channel is left inside the T-shaped nylon water cooling channel, 8 smoke sensors are installed on the upper part of the T-shaped nylon water cooling channel, and a temperature control module for executing the cooling control strategy is installed at the tail of the T-shaped nylon water cooling channel.

[0010] Above the first layer of lithium-ion batteries is a round-fin air-cooling plate; below the first layer of lithium-ion batteries is a thermally conductive silicone pad, and below the thermally conductive silicone pad is a liquid-cooled upper cover plate; below the liquid-cooled upper cover plate is an oblique-fin liquid-cooling plate, and the oblique-fin liquid-cooling plate is a liquid-cooled shell; below the liquid-cooled shell is a second layer of lithium-ion batteries, and below the second layer of lithium-ion batteries is an external fin-type phase change upper cover plate and an embedded fin-type phase change lower cover plate, and a composite phase change material is between the external fin-type phase change upper cover plate and the embedded fin-type phase change lower cover plate; the embedded fin-type phase change lower cover plate is placed on the lower cover plate.

[0011] The liquid-cooled upper cover plate, the oblique-fin liquid-cooling plate and the liquid-cooling shell constitute the liquid cooling layer of the device; the outer-finned phase-change upper cover plate, the composite phase-change material and the inner-finned phase-change lower cover plate constitute the phase-change cooling layer of the device; the circular-fin air-cooling plate is the natural cooling layer of the device; the first lithium-ion layer is located between the air-cooling layer and the liquid cooling layer; the second lithium-ion layer is located between the liquid cooling layer and the phase-change cooling layer to achieve heat transfer.

[0012] The peripheries of the first lithium-ion battery layer and the second lithium-ion battery layer are both wrapped with a honeycomb buffer layer, the honeycomb buffer layer is made of rubber, and a thermally conductive silicone pad is sandwiched between the battery layer and the liquid cooling layer.

[0013] The round-fin air-cooling plate is a cast round pin-fin structure with a staggered distribution.

[0014] The liquid cooling housing is provided with a liquid cooling plate cooling liquid inlet and outlet at the front and rear.

[0015] The housing is provided with a cooling liquid inlet and outlet at the front and rear; the cooling liquid inlet of the housing is connected via a cooling liquid pipeline.

[0016] The liquid cooling layer is connected by a liquid cooling shell, an oblique-fin liquid cooling plate and a liquid cooling upper cover plate through M6 bolts.

[0017] The present invention provides a method for collaborative thermal management of a power battery module with a composite pin-fin structure, comprising the following steps: (1) At a certain ambient temperature, the power battery module in the device begins to charge or discharge, and the natural cooling layer and phase change cooling layer perform passive thermal management through heat convection and heat conduction; (2) The temperature sensor detects the battery temperature and records it as Tbat. The temperature control module determines whether the battery temperature is higher than the safety upper limit of 60°C. If so, it transmits a temperature alarm signal. Otherwise, it performs weighted average processing on the temperature data. At the same time, the smoke sensor monitors whether the battery layer generates smoke. If so, it transmits an alarm signal. Otherwise, it loops the monitoring process. (3) Determine again whether Tbat is in the preset temperature range of 25℃<Tbat<30℃. If so, Tin=Tbat, and the coolant is not cooled or heated, and the coolant pipeline is closed. Otherwise, the coolant is heated or cooled, and the water pump is turned on to drive the coolant Vin, where Vin is the flow rate of the coolant. (4) Determine Tbat again. If Tbat is lower than the preset 25°C, use PTC to heat the coolant to Tin. If Tbat is higher than the preset 30°C, use Chiller to cool the coolant to Tin, where Tin is the coolant temperature.

[0018] The beneficial effect of the present invention is that the present invention is a composite pin-fin structure power battery module collaborative thermal management device and control method. The battery module is firstly passively thermally managed by air cooling and phase change materials. When the battery temperature exceeds the preset temperature, the coolant inlet conditions are adjusted in real time through the coolant control strategy, so that the power battery temperature is stabilized in a suitable operating temperature range. When thermal runaway is about to occur, an alarm is given in time. When the power battery collides, the battery is protected by collapse and energy absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the main structure of the power battery module collaborative thermal management device of the present invention; Figure 2 This is a schematic diagram of the explosion structure of the power battery module collaborative thermal management device of the present invention; Figure 3 It is a schematic diagram of the explosion structure of the battery layer in the power battery module collaborative thermal management device of the present invention; Figure 4 This is a schematic diagram of the structure of the liquid cooling layer of the power battery module collaborative thermal management device of the present invention; Figure 5 This is a schematic diagram of the phase change cooling layer structure of the power battery module collaborative thermal management device of the present invention; Figure 6 It is a schematic diagram of the cross-sectional structure of the power battery module collaborative thermal management device of the present invention; Figure 7 This is a flow chart of the operation of the power battery module collaborative thermal management device and control strategy of the present invention; In the figure: 1 is a round-fin air-cooled plate; 2 is a honeycomb buffer layer; 3 is an outer shell; 4 is a lower cover plate; 5 is a coolant pipe; 6 is a partition; 7 is a temperature sensor; 8 is a copper bar; 9 is a smoke sensor; 10 is a T-type nylon water-cooled channel; 11 is a temperature control module; 12 is a liquid-cooled upper cover plate; 13 is an M6 bolt; 14 is a liquid-cooled shell; 15 is a thermal conductive silicone pad; 16 is an external fin-type phase change upper cover plate; 17 is a composite phase change material; 18 is an embedded fin-type phase change lower cover plate; 19 is an oblique-fin liquid-cooled plate; 20 is a first lithium-ion battery layer; 21 is a second lithium-ion battery layer. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is shown in the figure.

[0021] This embodiment uses 32 square batteries to form a power battery module with nominal parameters of 59.2V 20Ah. The battery cells are connected by copper bars and the pole ears are cooled by T-shaped water cooling channels.

[0022] like Figure 6As shown, the present embodiment is a composite pin-fin structure power battery module collaborative thermal management device, including a shell 3 and a lower cover plate 4; it also includes a round fin air cooling plate 1, a first lithium ion battery layer 20, a second lithium ion battery layer 21, a liquid cooling upper cover plate 12, a thermal conductive silicone pad 15, an outer fin type phase change upper cover plate 16, a composite phase change material 17, an inner fin type phase change lower cover plate 18 and an oblique fin type liquid cooling plate 19. The above plates, layers, and pads are horizontally installed one by one in a rectangular hollow container formed by the shell 3 and the lower cover plate 4.

[0023] like Figure 1 As shown, the outer packaging layer of this embodiment includes a round-fin air-cooling plate 1, a honeycomb buffer layer 2, an outer shell 3, a lower cover plate 4 and a coolant pipeline 5.

[0024] like Figure 2 As shown, the inner layer comprises a battery layer composed of a first lithium-ion battery layer 20 and a second lithium-ion battery layer 21, a liquid cooling layer composed of a liquid-cooled upper cover plate 12, an oblique-fin liquid cooling plate 19, a liquid cooling shell 14 and a coolant, and a phase change cooling layer composed of an outer fin-type phase change upper cover plate 16, a composite phase change material 17 and an embedded fin-type phase change lower cover plate 18.

[0025] In this embodiment, the device housing 3 and the lower cover plate 4 are made of aluminum in one piece. The aluminum housing has the advantages of light weight and high thermal conductivity, which helps to reduce the weight of the system.

[0026] like Figure 3 As shown, the battery layers in this embodiment: the first lithium-ion battery layer 20 and the second lithium-ion battery layer 21 are both laid flat on the thermally conductive silicone pad 15 with the maximum contact area and separated by a partition 6, a temperature sensor 7 is attached between every two lithium-ion batteries for monitoring the temperature, and the positive and negative pole ears of the lithium-ion batteries are connected by a copper bar 8. Considering the heat generated by the ears, a T-shaped nylon water cooling channel 10 for cooling the copper bar 8 is arranged under the copper bar 8, and a smoke sensor 9 is arranged outside the channel. A temperature control module 11 is installed at the edge of the battery layer for executing a coolant cooling or heating strategy, and the periphery of the lithium-ion battery layer is wrapped with a honeycomb buffer layer 2.

[0027] The copper bar 8 in this embodiment is made of copper foil, which has the advantages of light weight and high thermal conductivity. The T-shaped nylon water cooling channel is made of nylon, which has electrical insulation and is widely used in the thermal management industry of new energy vehicles. The smoke sensor 9 and the temperature sensor 7 are evenly distributed between the lithium-ion batteries, which ensures the detection effect while reducing the cost.

[0028] In this embodiment, the cooling medium in the T-type nylon water-cooling channel 10 and the oblique-fin liquid cooling plate 19 is a water-ethylene glycol mixed solution, with the volume fraction of each accounting for 50%. The water-ethylene glycol solution has a lower freezing point and smaller dynamic viscosity than pure water.

[0029] The partition 6 in this embodiment is made of epoxy board, which has the functions of sealing and keeping cold, can isolate the heat between the lithium-ion batteries 20, and can effectively prevent the spread of heat diffusion and thermal runaway.

[0030] The honeycomb buffer layer 2 in this embodiment is made of rubber material. The rubber is relatively soft and can reduce impact with the honeycomb structure. At the same time, its thermal conductivity is low and it has a heat-insulating effect. The compression and rebound properties of the rubber will also increase as the temperature rises.

[0031] like Figure 4 As shown, the liquid cooling layer in this embodiment is composed of a liquid cooling shell 14, an oblique-fin liquid cooling plate 19 and a liquid cooling upper cover plate 12 connected by M6 bolts 13. The oblique fin layout in the fin plate can guide the fluid and reduce flow resistance.

[0032] like Figure 5 As shown, the phase change cooling layer in this embodiment adopts upper and lower different fin-type cover plates, the upper plate is an outer fin-type phase change upper cover plate 16, the lower plate is an inner fin-type phase change lower cover plate 18, and the composite phase change material 17 is filled between the two cover plates.

[0033] In this embodiment, the outer fins and the inner fins are a nestable structure, and the nested fins have a collapse buffer effect.

[0034] In this embodiment, the cooling layer and the battery layer are stacked in a stacking manner inside the device, so that the cooling surface of the upper and lower surfaces of the liquid cooling plate can be maximized to cool / preheat the battery module to the maximum extent. The fin structure can increase the contact area between the liquid cooling plate and the cooling medium, providing greater heat transfer capacity.

[0035] The summer high temperature cooling process of this embodiment is as follows: In the summer high temperature environment, the heat generated by the first lithium-ion battery layer 20 is transferred to the upper and lower surfaces of the liquid-cooled upper cover plate 12 and the liquid-cooled shell 14 through the thermally conductive silicone pad 15. At the same time, the heat of the upper battery layer is also transferred to the top round-fin air-cooled plate 1 for natural convection cooling; the heat of the second lithium-ion battery layer 21 is transferred to the bottom outer fin-type phase change upper cover plate 16. When the battery temperature exceeds the melting point of the phase change material, the phase change material absorbs the heat generated by the battery through the latent heat of phase change. During the operation of the lithium-ion battery, the temperature sensor 7 monitors the battery temperature in real time. If the temperature exceeds the set upper limit of 30°C, the temperature control module 11 adjusts the water pump or Chiller to increase the coolant flow rate or reduce the coolant temperature.

[0036] Winter low-temperature heating process of this embodiment: In winter low-temperature environment, the phase change material layer at the bottom plays a certain role in heat preservation. When this device is adapted to pure electric vehicles that are in the northern winter for a long time, the upper round-wing air-cooling plate 1 can be selected as a phase change material layer to provide better constant temperature function in winter. During the operation of the first lithium-ion battery layer 20, the temperature sensor 7 monitors the battery temperature in real time. If the battery temperature is lower than the set lower limit of 25°C, the temperature control module 11 adjusts the water pump or PTC to increase the coolant flow rate or increase the coolant temperature.

[0037] In this embodiment, a phase change material layer is installed at the bottom, and the composite phase change material 17 has a high compression resilience, which can reduce the impact and protect the second lithium ion battery layer 21 when the bottom of the car collides, thereby improving the car's passability. A honeycomb buffer layer 2 is installed on the side of the lithium ion battery layer in this device, and the car can collapse and absorb energy to protect the battery when the car collides from the side.

[0038] The composite phase change material 17 of this embodiment is a paraffin / expanded graphite composite phase change material, the mass fraction of expanded graphite is 20%, and the expanded graphite has a porous structure, which can absorb liquid paraffin to prevent paraffin leakage. When filling the composite phase change material 17, 20% of the composite phase change material 17 is reserved for heat absorption and expansion space.

[0039] In this embodiment, the outer fin-type phase change upper cover plate 16, the inner fin-type phase change lower cover plate 18, the oblique fin liquid cooling plate 19 and the round fin air cooling plate 1 are all made of aluminum, which is convenient for modular replacement.

[0040] like Figure 7 As shown, the present embodiment provides a method for collaborative thermal management control of a power battery module with a composite pin-fin structure, comprising the following steps: Step 1: At a certain ambient temperature, the power battery module in the device starts to charge or discharge, and the natural cooling layer and the phase change cooling layer perform passive thermal management through heat convection and heat conduction.

[0041] Step 2, the temperature sensor 7 detects the battery temperature and records it as Tbat, and the temperature control module 11 determines whether the temperature of the lithium-ion battery layer 20 is higher than the safety upper limit of 60°C, if yes, a temperature alarm signal is transmitted, otherwise the temperature data is weighted averaged; at the same time, the smoke sensor 9 monitors whether the battery layer generates smoke, if yes, an alarm signal is transmitted, otherwise the monitoring process is cyclic.

[0042] Step 3, determine again whether Tbat is in the preset temperature range of 25℃<Tbat<30℃, if so, the coolant temperature Tin=Tbat, the coolant is not cooled or heated, and the coolant pipe 5 is closed, otherwise the coolant is heated or cooled, and the water pump is turned on to drive the coolant Vin.

[0043] Step 4: Determine Tbat again. If Tbat is lower than the preset 25°C, use PTC to heat the coolant to Tin. If Tbat is higher than the preset 30°C, use Chiller to cool the coolant to Tin.

[0044] Furthermore, the coolant Tin and the coolant flow rate Vin are calculated based on Tbat, and 0.075 and 0.008 in the control strategy are temperature control and speed control coefficients, which can be customized and adjusted.

Claims

1. A power battery module collaborative thermal management device with a composite pin-fin structure, comprising a housing and a lower cover plate, characterized in that: The device also includes a round-fin air-cooling plate, a first lithium-ion battery layer, a second lithium-ion battery layer, a liquid-cooling upper cover plate, a liquid-cooling shell, a thermally conductive silicone pad, an outer fin-type phase-change upper cover plate, a composite phase-change material, an inner fin-type phase-change lower cover plate, and an oblique-fin liquid-cooling plate; The first lithium-ion battery layer and the second lithium-ion battery layer each include 16 square lithium-ion battery cells connected in series; the first lithium-ion battery layer and the second lithium-ion battery layer are connected in parallel to form a battery module; the lithium-ion battery cells are separated by partitions, and 14 temperature sensors are arranged on the sides of the lithium-ion battery cells; the 16 lithium-ion batteries in each layer are divided into two groups side by side, and a smoke sensor and a T-shaped nylon water cooling channel are arranged between the two groups of lithium-ion battery cells; the lithium-ion batteries are connected by copper bars, and the copper bars are installed on both sides of the upper and lower ears of each battery cell, and the copper bars are attached to the T-shaped nylon water cooling channel, and a U-shaped coolant channel is left inside the T-shaped nylon water cooling channel, and 8 smoke sensors are installed on the upper part of the T-shaped nylon water cooling channel, and a temperature control module for executing a cooling control strategy is installed at the tail of the T-shaped nylon water cooling channel; The first layer of lithium-ion batteries is provided with a round-fin air-cooling plate above; the first layer of lithium-ion batteries is provided with a thermally conductive silicone pad below, and the liquid-cooling upper cover plate below the thermally conductive silicone pad; the liquid-cooling upper cover plate is provided with an oblique-fin liquid-cooling plate and a liquid-cooling housing below; the second layer of lithium-ion batteries is provided with a second layer of lithium-ion batteries, and the second layer of lithium-ion batteries is provided with an external fin-type phase-change upper cover plate and an internal fin-type phase-change lower cover plate below, and a composite phase-change material is provided between the external fin-type phase-change upper cover plate and the internal fin-type phase-change lower cover plate; the internal fin-type phase-change lower cover plate is provided on the lower cover plate; The liquid-cooled upper cover plate, the oblique-fin liquid-cooling plate and the liquid-cooling shell constitute the liquid cooling layer of the device; the outer-finned phase-change upper cover plate, the composite phase-change material and the inner-finned phase-change lower cover plate constitute the phase-change cooling layer of the device; the circular-fin air-cooling plate is the natural cooling layer of the device; the first lithium-ion layer is located between the air-cooling layer and the liquid cooling layer; the second lithium-ion layer is located between the liquid cooling layer and the phase-change cooling layer to achieve heat transfer.

2. The power battery module collaborative thermal management device of a composite pin-fin structure according to claim 1, characterized in that: The peripheries of the first lithium-ion battery layer and the second lithium-ion battery layer are both wrapped with a honeycomb buffer layer, the honeycomb buffer layer is made of rubber, and a thermally conductive silicone pad is sandwiched between the battery layer and the liquid cooling layer.

3. The power battery module collaborative thermal management device of a composite pin-fin structure according to claim 1, characterized in that: The round-fin air-cooling plate is a cast round pin-fin structure with a staggered distribution.

4. The power battery module collaborative thermal management device of a composite pin-fin structure according to claim 1, characterized in that: The liquid cooling housing is provided with a liquid cooling plate cooling liquid inlet and outlet at the front and rear.

5. The power battery module collaborative thermal management device of a composite pin-fin structure according to claim 1, characterized in that: The housing is provided with a cooling liquid inlet and outlet at the front and rear; the cooling liquid inlet of the housing is connected via a cooling liquid pipeline.

6. The power battery module collaborative thermal management device of a composite pin-fin structure according to claim 1, characterized in that: The liquid cooling layer is connected by a liquid cooling shell, an inclined fin type liquid cooling plate and a liquid cooling upper cover plate through M6 bolts.

7. A method for collaborative thermal management of a power battery module with a composite pin-fin structure using the power battery module collaborative thermal management device with a composite pin-fin structure according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: (1) At a certain ambient temperature, the power battery module in the device begins to charge or discharge, and the natural cooling layer and phase change cooling layer perform passive thermal management through heat convection and heat conduction; (2) The temperature sensor detects the battery temperature and records it as Tbat. The temperature control module determines whether the battery temperature is higher than the safety upper limit of 60°C. If so, it transmits a temperature alarm signal. Otherwise, it performs weighted average processing on the temperature data. At the same time, the smoke sensor monitors whether the battery layer generates smoke. If so, it transmits an alarm signal. Otherwise, it loops the monitoring process. (3) Determine again whether Tbat is in the preset temperature range of 25℃<Tbat<30℃. If so, Tin=Tbat, and the coolant is not cooled or heated, and the coolant pipeline is closed. Otherwise, the coolant is heated or cooled, and the water pump is turned on to drive the coolant Vin, where Vin is the flow rate of the coolant after the variable flow rate processing; (4) Determine Tbat again. If Tbat is lower than the preset 25°C, use PTC to heat the coolant to Tin. If Tbat is higher than the preset 30°C, use Chiller to cool the coolant to Tin, where Tin is the temperature of the coolant after temperature change treatment.

8. A method for collaborative thermal management of a power battery module with a composite pin-fin structure according to claim 7. Characterized in that: The coolant temperature Tin after the variable temperature treatment and the coolant flow rate Vin after the variable flow rate treatment are calculated according to Tbat, and 0.075 and 0.008 in the control strategy are temperature control and speed control coefficients, or user-defined adjustments.

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