Battery module cooling method and battery pack with variable flow channel air cooling based on PID control strategy

Abstract

The present invention provides a battery module cooling method based on a PID control strategy and variable flow channel air cooling. The method collects temperature signals of various parts of the battery module through multiple temperature sensors and transmits them to the battery management system. When the battery management system calculates ΔT max >ΔT L ‑δ, where ΔT max is the maximum temperature difference of the battery module, ΔT L is the temperature difference threshold, and the error is δ, then it is determined that the temperature difference of each part of the battery module exceeds the preset temperature difference threshold, and the maximum temperature T of the battery module is obtained. max The location and control of the maximum temperature T max The control valve corresponding to the location is opened, and the control valves at the other outlets are closed, thus switching to the convection mode. This can cool the battery module in a multi-directional and more comprehensive manner, and can allow more air to flow through the locally overheated parts of the battery module, which is more conducive to heat dissipation in the locally overheated parts and avoid the risk of battery overheating.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management of automotive power batteries, and in particular to a battery module cooling method and a battery pack with variable flow channel air cooling based on a PID control strategy. Background Art

[0002] The new energy vehicle industry is developing rapidly. As a core component of new energy vehicles, ensuring the safe and efficient operation of power battery systems is crucial. Battery modules are composed of numerous individual cells. Internal and external factors such as inconsistencies and operating conditions can cause overheating, leading to a series of problems. This can accelerate chemical reactions within the battery, affect material properties, and even cause overheating and explosion. This shortens battery life, reduces energy density, and decreases safety, making it difficult to ensure the efficient and safe operation of electric vehicles. Therefore, a thermal management system must be designed to ensure that the battery module operating temperature remains within the appropriate range. Current mainstream thermal management technologies, such as air cooling and liquid cooling, are inefficient, space-consuming, and energy-intensive, making them no longer suitable for future battery thermal management trends.

[0003] In the prior art, a Chinese invention patent application with publication number CN117039246A discloses a method for controlling air-cooling zones for electric energy storage. The method includes: constructing an air-cooling duct, which includes an air-cooling system positioned above the battery pack, a fan corresponding to each battery pack located in the air inlet direction of the air-cooling system, and a fan corresponding to each battery pack located in the air outlet direction. The fan speed is set in 1 to n levels, ranging from low to high speed; activating air conditioning heating or cooling based on temperature differences, and adjusting the fan position based on the extreme difference to control the overall temperature of the battery pack. However, this method requires a fan for each battery pack, resulting in a larger installation space and higher costs. In addition, the system needs to control multiple fans, which increases system costs and maintenance difficulties.

[0004] Chinese invention patent publication number CN105552474B discloses a circulating air cooling device for power batteries. Its control device collects temperature readings from temperature sensors at both ends of the battery, determines whether the temperature difference between the two points reaches a fixed value, and then controls the opening and closing of the air inlet and outlet valves, cyclically switching the air flow path and achieving air circulation within the battery compartment. However, by only collecting temperature readings at the battery terminals, it cannot fully reflect the temperature distribution within the battery module, and therefore cannot accurately control the internal temperature of the battery compartment. Furthermore, by controlling the opening and closing of each valve, the air flow path within the battery compartment flows in two opposite directions, achieving a cyclic switching of the cooling air direction for the battery module, ensuring that the maximum temperature and temperature difference of the battery module remain within a normal range. This method can only regulate the heat dissipation rate of batteries near the air inlet, but it is difficult to control the temperature of batteries farther away from the air inlet. Furthermore, when switching the air flow direction, the battery management system controls the fan to stop for a fixed period of time to avoid impact with air flowing in the opposite direction. This can cause the temperature of already overheated batteries to rise further rapidly, leading to the risk of battery overheating. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems raised in the above-mentioned background technology, and provides a battery module cooling method with variable flow channel air cooling based on PID control strategy, which can cool the battery module in multiple directions and more comprehensively, and can allow more air to flow through the locally overheated parts of the battery module, which is more conducive to the heat dissipation of the locally overheated parts and avoids the risk of battery overheating.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A battery module cooling method with variable flow channel air cooling based on a PID control strategy comprises the following steps:

[0008] A battery pack is provided, comprising a housing, a battery module, a plurality of temperature sensors, and a battery management system. The housing comprises an outer housing and an inner housing fixed therein, an air duct being provided between the inner housing and the outer housing, the air duct having an air inlet and a plurality of air outlets, the air inlet being provided at the bottom of the housing, and a plurality of air outlets being provided at intervals at the top of the housing, each of the air outlets being provided with a control valve. The battery module is provided within the inner housing, the plurality of temperature sensors being connected to the inner housing at intervals, and the battery management system being electrically connected to the plurality of temperature sensors and the control valves at the respective air outlets.

[0009] The temperature sensors are used to collect temperature signals from various parts of the battery module and transmit the temperature signals to the battery management system;

[0010] When the battery management system calculates ΔT max >ΔT L -δ, where ΔT max is the maximum temperature difference of the battery module, ΔT L If the temperature difference threshold is δ and the error is δ, it is determined that the maximum temperature difference of each part of the battery module exceeds the preset temperature difference threshold, and the maximum temperature T of the battery module is obtained. max The location is controlled and the maximum temperature T max The control valve corresponding to the position is opened, and the control valves at the other air outlets are closed, thereby switching to the flow channel mode.

[0011] Furthermore, the air outlet includes a first air outlet, a second air outlet and a third air outlet, the first air outlet is arranged on the left side of the top of the box body, the second air outlet is arranged on the right side of the top of the box body, and the third air outlet is arranged in the middle position of the top of the box body.

[0012] Furthermore, when the maximum temperature of the battery module T max Located on the left side of the battery module, open the control valve corresponding to the first air outlet, and close the control valves corresponding to the second air outlet and the third air outlet, so that air enters from the bottom of the box and leaves from the left side of the top of the box, thereby allowing more air to flow through the left side of the battery module.

[0013] Furthermore, when the maximum temperature of the battery module T max When it is located in the middle position of the battery module, the control valve corresponding to the third air outlet is opened, and the control valves corresponding to the first air outlet and the second air outlet are closed, so that air enters from the bottom of the box and leaves from the third air outlet, thereby allowing more air to flow through the middle position of the battery module.

[0014] Furthermore, when the maximum temperature of the battery module T max Located on the right side of the battery module, open the control valve corresponding to the second air outlet, and close the control valves corresponding to the first air outlet and the third air outlet, so that air enters from the bottom of the box and leaves from the right side of the top of the box, thereby allowing more air to flow through the right side of the battery module.

[0015] Furthermore, when the temperatures at the left and right positions of the battery module are higher than the temperature at the middle position, the control valves corresponding to the first air outlet and the second air outlet are opened, and the control valve corresponding to the third air outlet is closed, so that air can flow from the left and right positions of the battery module.

[0016] Furthermore, after the flow channel mode is switched, the temperature sensor continues to collect temperature signals. If ΔT max ≤ΔT L -δ, then maintain the current flow channel mode. If ΔT max >ΔT L -δ, then continue mode switching.

[0017] Furthermore, the battery management system sends a signal to the corresponding control valve according to the PID control algorithm, thereby controlling the operation of the corresponding control valve, thereby switching the flow channel mode.

[0018] The present invention also provides a battery pack, comprising a case, a battery module, multiple temperature sensors and a battery management system, wherein the case comprises an outer shell and an inner shell fixed inside the outer shell, an air flow channel is provided between the inner shell and the outer shell, the air flow channel has an air inlet and multiple air outlets, the air inlet is provided at the bottom of the case, and multiple air outlets are provided at intervals at the top of the case, and a control valve is provided at each air outlet; the battery module is provided in the inner shell, and multiple temperature sensors are connected to the inner shell at intervals, and the battery management system is electrically connected to the multiple temperature sensors and the control valves at each air outlet.

[0019] Furthermore, the battery pack also includes a heat dissipation component arranged between the inner shell and the outer shell, and the heat dissipation component includes a heat conduction plate, a semiconductor refrigeration plate and a heat sink. The heat conduction plate covers the outer surface of the inner shell, the cold end of the semiconductor refrigeration plate is attached to the heat conduction plate, and the heat sink is attached to the hot end of the semiconductor refrigeration plate.

[0020] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0021] 1. The battery module cooling method with variable flow channel air cooling based on PID control strategy is provided with multiple temperature sensors on the inner shell of the battery pack, and the temperature of each part of the battery module can be collected by the multiple temperature sensors; when ΔT max >ΔT L -δ, the maximum value of the temperature difference of each part of the battery module is determined to exceed the threshold, and the highest temperature position T of the battery module is obtained. max, control the control valve corresponding to this position to open, and close the valves at other positions, so that more air flows through the position with the highest temperature, which is beneficial to the heat dissipation of the battery at this position. Therefore, the above-mentioned variable flow channel air cooling battery module cooling method based on the PID control strategy can cool the battery module in multiple directions and more comprehensively, and can concentrate the air on the local overheating part of the battery module, which is more conducive to the heat dissipation of the local overheating part and avoids the risk of overheating of the battery. At the same time, the above-mentioned variable flow channel air cooling battery module cooling method based on the PID control strategy only needs to install a fan at the air inlet. Compared with the Chinese invention patent application with publication number CN117039246A, which discloses an air-cooling zoning control method for electric energy storage, it can reduce the installation area required for the battery pack, requires fewer components, can reduce the weight of the entire vehicle, improve the energy efficiency of the vehicle, and has low system cost and maintenance difficulty.

[0022] 2. The cooling method of the existing technology is usually passive cooling, that is, the temperature of the battery module needs to be higher than the ambient temperature before its heat dissipation component can have a heat dissipation function; the battery pack used in the variable flow channel air cooling battery module cooling method based on the PID control strategy mentioned above has a heat dissipation component including a heat conducting plate, a semiconductor cooling plate and a heat sink. The cold end is tightly fitted with the heat conducting plate to absorb the heat of the battery module, and the hot end is fitted with the heat sink to release heat, so that the semiconductor cooling plate continuously removes the heat generated by the battery module during operation, actively cooling the battery module. The temperature of the cold end can be controlled within a set range, and the heat dissipation effect is better for battery modules with high heating power. At the same time, the semiconductor cooling plate and heat sink of the heat dissipation component can adapt to different environments, and have a simple structure, few parts, and a light overall weight. It does not require the use of any refrigerant, can work continuously, is pollution-free, has no moving parts, is silent, has a long life, is easy to install, and is small in size and light in weight, making it easy to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of a battery pack according to a preferred embodiment of the present invention when all control valves are in a closed state;

[0024] Figure 2 for Figure 1 A schematic diagram of the structure of the battery pack shown when the control valve at the first gas outlet is in an open state;

[0025] Figure 3 for Figure 1 A schematic diagram of the structure of the battery pack shown when the control valve at the third gas outlet is in the open state;

[0026] Figure 4 for Figure 1 A schematic diagram of the structure of the battery pack shown when the control valve at the second gas outlet is in the open state;

[0027] Figure 5 for Figure 1 A schematic diagram of the structure of the battery pack shown when the control valves at the first air outlet and the second air outlet are in the open state;

[0028] Figure 6 This is a flow chart of a battery module cooling method using variable flow channel air cooling based on a PID control strategy according to a preferred embodiment of the present invention;

[0029] Description of main component symbols

[0030] 10. Battery pack; 11. Box; 112. Outer shell; 113. Inner shell; 1130. Installation space; 114. Air flow channel; 115. Air inlet; 116. Air outlet; 117. First air outlet; 118. Second air outlet; 119. Third air outlet; 12. Control valve; 13. Battery module; 15. Temperature sensor; 17. Heat dissipation assembly; 171. Heat conduction plate; 172. Semiconductor cooling plate; 173. Heat sink. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] Please also see Figures 1 to 6 A preferred embodiment of the present invention provides a battery module cooling method using variable flow channel air cooling based on a PID control strategy, comprising the following steps:

[0035] S1 , providing a battery pack 10 , which includes a housing 11 , battery modules 13 , a plurality of temperature sensors 15 and a battery management system (BMS system, not shown).

[0036] The housing 11 includes an outer shell 112 and an inner shell 113 fixed within the outer shell 112. An air duct 114 is provided between the inner shell 113 and the outer shell 112. In this embodiment, the outer shell 112 and the inner shell 113 are both roughly rectangular, and the air duct 114 is arranged around the outer periphery of the inner shell 113. The air duct 114 has an air inlet 115 and a plurality of air outlets 116. The air inlet 115 and the plurality of air outlets 116 extend through the outer shell 112 of the housing 11 to communicate with the air duct 114. The air inlet 115 is provided at the bottom of the housing 11. A fan (not shown) may be provided at the air inlet 115 to draw air into the air duct 114 through the air inlet 115. A plurality of air outlets 116 are spaced apart at the top of the housing 11. Each air outlet 116 is provided with a control valve 12 for controlling the opening and closing of the corresponding air outlet 116. In this embodiment, the air outlet 116 includes a first air outlet 117, a second air outlet 118 and a third air outlet 119. The first air outlet 117 is arranged on the left side of the top of the box body 11, the second air outlet 118 is arranged on the right side of the top of the box body 11, and the third air outlet 119 is arranged in the middle position of the top of the box body 11. The first air outlet 117, the second air outlet 118 and the third air outlet 119 are all provided with a control valve 12.

[0037] The inner shell 113 defines an installation space 1130 for mounting the battery module 13. The battery module 13 is disposed within the installation space 1130 of the inner shell 113. In this embodiment, the battery module 13 includes nine power battery cells. The mass of the battery module 13 accounts for approximately 20% of the vehicle system weight, and the mass of the housing 11 accounts for approximately 10% of the total battery pack weight. It will be appreciated that in other embodiments, the number of cells, the weight of the battery module 13, and the weight of the housing 11 may be set to other values ​​as desired, and this invention does not impose any limitation thereto.

[0038] The battery pack 10 also includes a heat dissipation component 17 disposed between the inner shell 113 and the outer shell 112. In this embodiment, the heat dissipation component 17 includes a heat conducting plate 171, a semiconductor refrigeration plate 172, and a heat sink 173. The heat conducting plate 171 covers the outer surface of the inner shell 113; the cold end of the semiconductor refrigeration plate 172 is attached to the side of the heat conducting plate 171 away from the inner shell 113; and the heat sink 173 is attached to the hot end of the semiconductor refrigeration plate 172. The material of the heat conducting plate 171 in this embodiment is an aluminum-silicon alloy, which has a low density and good thermal conductivity. The function of the heat conducting plate 171 is to receive the heat emitted by the battery module 13 during operation, avoiding direct contact between the semiconductor refrigeration plate 172 and the inner shell 113 while ensuring timely heat transfer.

[0039] The current passing through the semiconductor refrigeration chip 172 should be between 10mA and 100mA, and the voltage across the two ends should not exceed 15V, which should be adjusted according to different application scenarios. Thermal conductivity is an important parameter for measuring the cooling effect of the semiconductor refrigeration chip 172. In this embodiment, the thermal conductivity should be between 10W and 50W. The maximum temperature difference is an indicator of the cooling capacity of the semiconductor refrigeration chip 172. In this embodiment, the temperature difference range should be between -50°C and 70°C. The heat sink 173 is made of aluminum-silicon alloy, which has high thermal conductivity.

[0040] Multiple temperature sensors 15 are spaced apart on the outer surface of the inner shell 113 to monitor the temperature around, at the top, and at the bottom of the battery pack in real time. In this embodiment, the temperature sensors 15 are mounted on the outside of the heat sink 173 and connected to the outer surface of the inner shell 113 via the heat sink 173. The temperature sensors 15 are positioned around, at the top, and at the bottom of the battery module 13. In this embodiment, the temperature sensors 15 are thermistors, which offer high sensitivity and a wide operating temperature range.

[0041] The battery management system is electrically connected to multiple temperature sensors 15 and the control valves 12 at each gas outlet 116. This embodiment utilizes a conventional battery management system, which will not be described here for the sake of brevity. In this embodiment, the battery management system sends signals to the corresponding control valves 12 based on a PID control algorithm, thereby controlling the opening and closing of the control valves 12.

[0042] S2, collecting temperature signals of various parts of the battery module 13 through multiple temperature sensors 15 and transmitting them to the battery management system.

[0043] S3, within the preset time period, when the battery management system calculates ΔT max >ΔT L -δ, where ΔT max is the maximum temperature difference of the battery module 13, ΔT LThe maximum temperature difference of each part of the battery module 13 exceeds the set temperature difference threshold, and the error is δ. The maximum temperature T of the battery module 13 is obtained. max The location and control of the maximum temperature T max The control valve 12 corresponding to the position is opened, and the control valves 12 at the other gas outlets 116 are closed to switch the flow channel mode.

[0044] Specifically, in this embodiment, ΔT max The temperature sensor 15 collects the temperature signals of various parts of the battery pack 10, and then calculates the temperature difference between the various parts based on the collected temperature signals. Finally, the maximum value of each temperature difference is taken, which is ΔT max . T max The temperature sensor 15 is used to collect the temperature signals of various parts of the battery pack 10, and the maximum temperature is ΔT max When T max Located on the left side of the battery module 13, the control valve 12 corresponding to the first air outlet 117 is opened, and the control valves 12 corresponding to the second air outlet 118 and the third air outlet 119 are closed, so that air enters from the bottom of the box body 11 and leaves from the left side of the top of the box body 11, thereby allowing more air to flow through the left side of the battery module 13, which is more conducive to heat dissipation. max When the battery module 13 is in the middle, the control valve 12 corresponding to the third air outlet 119 is opened, and the control valves 12 corresponding to the first air outlet 117 and the second air outlet 118 are closed, so that air enters from the bottom of the box 11 and leaves from the third air outlet 119, thereby allowing more air to flow through the middle position of the top of the box 11, which is more conducive to cooling the battery module 13 in the middle. max Located on the right side of the battery module 13, the control valve 12 corresponding to the second air outlet 118 is opened, and the control valves 12 corresponding to the first air outlet 117 and the third air outlet 119 are closed, allowing air to enter from the bottom of the box body 11 and exit from the right side of the top of the box body 11, thereby allowing more air to flow through the right side of the battery module 13, which is more conducive to heat dissipation. In addition, when the temperature at the left and right sides of the battery module 13 is higher than the temperature at the middle position, the control valves 12 corresponding to the first air outlet 117 and the second air outlet 118 are opened, and the control valve 12 corresponding to the third air outlet 119 is closed, allowing more air to circulate from the left and right sides of the battery module 13 to remove heat.

[0045] After the flow channel mode is switched, the temperature sensor 15 continues to collect temperature signals. If ΔT max ≤ΔT L -δ, then maintain the current flow channel mode. If ΔT max >ΔTL -δ, then continue mode switching.

[0046] In the above-mentioned variable flow channel air cooling method for the battery module 13 based on the PID control strategy, a plurality of temperature sensors 15 are provided on the inner shell 113 of the battery pack 10, and the temperature of each part of the battery module 13 can be collected by the plurality of temperature sensors 15; when ΔT max >ΔT L -δ, it is determined that the maximum temperature difference of each part of the battery pack exceeds the set temperature difference threshold, and the highest temperature position T of the battery pack 10 is obtained. max , control the control valve 12 corresponding to this position to open, and close the valves at other positions, so that air flows through the position with the highest temperature, thereby facilitating the heat dissipation of the battery at this position. Therefore, the above-mentioned variable flow channel air cooling battery module 13 cooling method based on the PID control strategy can cool the battery module 13 in multiple directions and more comprehensively, and can concentrate the air on the local overheating part of the battery module 13, which is more conducive to the heat dissipation of the local overheating part and avoids the risk of overheating of the battery. At the same time, the above-mentioned variable flow channel air cooling battery module 13 cooling method based on the PID control strategy only requires the installation of a fan at the air inlet. Compared with the Chinese invention patent application with publication number CN117039246A, which discloses an air cooling zoning control method for electric energy storage, it can reduce the installation area required for the battery pack 10, requires fewer components, can reduce the weight of the entire vehicle, improve the energy efficiency of the vehicle, and has low system cost and maintenance difficulty.

[0047] The cooling method of the prior art is usually passive cooling, that is, the temperature of the battery module 13 needs to be higher than the ambient temperature before its heat dissipation component 17 can have a heat dissipation function. The battery pack 10 used in the variable flow channel air cooling battery module 13 cooling method based on the PID control strategy is characterized by a heat dissipation component 17 including a heat conducting plate 171, a semiconductor cooling plate 172, and a heat sink 173. The cold end is tightly attached to the heat conducting plate 171 to absorb the heat of the battery module 13, and the hot end is attached to the heat sink 173 to release the heat. The semiconductor cooling plate 172 continuously removes the heat generated by the battery module 13 during operation, actively cooling the battery module 13. The temperature of the cold end can be controlled within a set range, and the heat dissipation effect is better for battery modules 13 with high heating power. At the same time, the semiconductor cooling plate 172 and the heat sink 173 of the heat dissipation component 17 can adapt to different environments, and have a simple structure, few parts, and a light overall weight. It does not require the use of any refrigerant, can operate continuously, is pollution-free, has no moving parts, is silent, has a long life, is easy to install, and is small and light, and easy to maintain.

[0048] The above description is a detailed description of the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A battery module cooling method with variable flow channel air cooling based on PID control strategy, characterized in that: The following steps are involved: A battery pack is provided, comprising a housing, a battery module, a plurality of temperature sensors, and a battery management system. The housing comprises an outer housing and an inner housing fixed therein, an air duct being provided between the inner housing and the outer housing, the air duct having an air inlet and a plurality of air outlets, the air inlet being provided at the bottom of the housing, and a plurality of air outlets being provided at intervals at the top of the housing, each of the air outlets being provided with a control valve. The battery module is provided within the inner housing, the plurality of temperature sensors being connected to the inner housing at intervals, and the battery management system being electrically connected to the plurality of temperature sensors and the control valves at the respective air outlets. The temperature sensors are used to collect temperature signals from various parts of the battery module and transmit the temperature signals to the battery management system; When the battery management system calculates ΔT max >ΔT L -δ, where ΔT max is the maximum temperature difference of the battery module, ΔT L If the temperature difference threshold is δ and the error is δ, it is determined that the maximum temperature difference of each part of the battery module exceeds the preset temperature difference threshold, and the maximum temperature T of the battery module is obtained. max The location is controlled and the maximum temperature T max The control valve corresponding to the position is opened, and the control valves at the other air outlets are closed, thereby switching the flow channel mode.

2. The battery module cooling method with variable flow channel air cooling based on PID control strategy according to claim 1, characterized in that: The air outlet includes a first air outlet, a second air outlet and a third air outlet. The first air outlet is arranged on the left side of the top of the box body, the second air outlet is arranged on the right side of the top of the box body, and the third air outlet is arranged in the middle position of the top of the box body.

3. The battery module cooling method with variable flow channel air cooling based on PID control strategy according to claim 2, characterized in that: When the maximum temperature of the battery module T max Located on the left side of the battery module, open the control valve corresponding to the first air outlet, and close the control valves corresponding to the second air outlet and the third air outlet, so that air enters from the bottom of the box and leaves from the left side of the top of the box, thereby allowing more air to flow through the left side of the battery module.

4. The battery module cooling method with variable flow channel air cooling based on PID control strategy according to claim 2, characterized in that: When the maximum temperature of the battery module T max When it is located in the middle position of the battery module, the control valve corresponding to the third air outlet is opened, and the control valves corresponding to the first air outlet and the second air outlet are closed, so that air enters from the bottom of the box and leaves from the third air outlet, thereby allowing more air to flow through the middle position of the battery module.

5. The battery module cooling method with variable flow channel air cooling based on PID control strategy according to claim 2, characterized in that: When the maximum temperature of the battery module T max Located on the right side of the battery module, open the control valve corresponding to the second air outlet, and close the control valves corresponding to the first air outlet and the third air outlet, so that air enters from the bottom of the box and leaves from the right side of the top of the box, thereby allowing more air to flow through the right side of the battery module.

6. The battery module cooling method with variable flow channel air cooling based on PID control strategy according to claim 2, characterized in that: When the temperatures at the left and right positions of the battery module are both higher than the temperature at the middle position, the control valves corresponding to the first air outlet and the second air outlet are opened, and the control valve corresponding to the third air outlet is closed, so that air can flow from the left and right positions of the battery module.

7. The battery module cooling method with variable flow channel air cooling based on PID control strategy according to claim 2, characterized in that: After the flow channel mode is switched, the temperature sensor continues to collect temperature signals. If ΔT max ≤ΔT L -δ, then maintain the current flow channel mode. If ΔT max >ΔT L -δ, then continue mode switching.

8. The battery module cooling method with variable flow channel air cooling based on PID control strategy according to claim 2, characterized in that: The battery management system sends a signal to the corresponding control valve according to the PID control algorithm, thereby controlling the operation of the corresponding control valve, thereby switching the flow channel mode.

9. A battery pack, characterized in that: The invention comprises a box, a battery module, a plurality of temperature sensors and a battery management system, wherein the box comprises an outer shell and an inner shell fixed inside the outer shell, an air flow channel is provided between the inner shell and the outer shell, the air flow channel has an air inlet and a plurality of air outlets, the air inlet is provided at the bottom of the box, a plurality of the air outlets are provided at intervals at the top of the box, and a control valve is provided at each of the air outlets; the battery module is provided in the inner shell, a plurality of the temperature sensors are connected to the inner shell at intervals, the battery management system is electrically connected to the plurality of the temperature sensors and the control valves at each of the air outlets; the temperature signals of various parts of the battery module are collected by the plurality of the temperature sensors and transmitted to the battery management system; when the battery management system calculates ΔT max >ΔT L -δ, where ΔT max is the maximum temperature difference of the battery module, ΔT L If the temperature difference threshold is δ and the error is δ, it is determined that the maximum temperature difference of each part of the battery module exceeds the preset temperature difference threshold, and the maximum temperature T of the battery module is obtained. max The location is controlled and the maximum temperature T max The control valve corresponding to the position is opened, and the control valves at the other air outlets are closed, thereby switching the flow channel mode.

10. The battery pack according to claim 9, wherein: The battery pack also includes a heat dissipation component arranged between the inner shell and the outer shell, and the heat dissipation component includes a heat conduction plate, a semiconductor refrigeration plate and a heat sink. The heat conduction plate covers the outer surface of the inner shell, the cold end of the semiconductor refrigeration plate is attached to the heat conduction plate, and the heat sink is attached to the hot end of the semiconductor refrigeration plate.

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