An eVTOL battery pack thermal management system based on a triple medium heat exchanger

Abstract

The application discloses an eVTOL battery pack thermal management system based on a three-medium heat exchanger, which comprises an airborne battery pack cooling module, a three-medium heat exchanger module and a ground cooling system; the airborne battery pack cooling module is connected with a battery pack cold plate, the three-medium heat exchanger module and a liquid accumulator through gas pipes and liquid pipes, and constitutes a complete natural circulation loop, and in the level flight stage, two-phase thermosyphon circulation is utilized to realize zero-power-consumption and high-reliability heat dissipation; the core three-medium heat exchanger module integrates flow channels of three mediums, namely, airborne cooling liquid, ground cooling liquid and air, and serves as a key heat exchange hub; the application solves the battery heat dissipation problem of eVTOL in the whole task cycle, has high reliability, high energy efficiency and strong heat dissipation capacity, and reduces the weight and volume of the battery pack thermal management system.

Description

Technical Field

[0001] This invention relates to the field of eVTOL battery packs, specifically to an eVTOL battery pack thermal management system based on a three-medium heat exchanger. This system combines airborne thermosiphon cooling and ground-based active cooling, and is efficiently coupled through a three-medium heat exchanger module, aiming to meet different heat dissipation requirements at different stages. Background Technology

[0002] The dynamic performance and safety of electric vertical takeoff and landing (eVTOL) aircraft are closely related to the operating temperature of their battery packs. The thermal management requirements of the battery packs vary significantly under different operating conditions, posing a serious challenge to the thermal management system.

[0003] During the takeoff phase of an eVTOL, the battery discharges at a high rate, generating a large amount of heat instantaneously and requiring significant heat dissipation. Although this phase is relatively short, the system still needs to have excellent peak heat dissipation capabilities to prevent battery temperature runaway within limited weight and space constraints.

[0004] During the level flight phase, eVTOL batteries generate heat steadily, requiring relatively little heat dissipation over a long period. Combined with the low-temperature environment at high altitudes, effective heat dissipation is easily achieved. However, the extended flight time places stringent demands on system reliability, weight, and energy consumption. Therefore, during this phase, an ideal thermal management system should fully utilize ambient cooling sources, operate with high reliability and low energy consumption, and minimize system weight.

[0005] The most severe challenge lies in heat dissipation during fast charging on the ground. The Joule heat generated by high-current charging far exceeds that during level flight, resulting in immense and continuous heat dissipation. Simultaneously, the high ambient temperature significantly reduces air cooling efficiency, leading to a rapid accumulation of heat that is difficult to cool effectively. Relying solely on onboard cooling fins and fans is not only insufficient for heat dissipation but also consumes battery energy, severely limiting charging speed and battery safety.

[0006] Therefore, there is an urgent need in this field for a new solution that must be able to: 1) have peak heat dissipation capacity and achieve lightweighting during takeoff; 2) fully utilize the advantages of high-altitude low temperature during level flight to achieve high reliability and low energy consumption heat dissipation, and contribute to system lightweighting; and 3) be able to quickly and seamlessly connect to a more powerful external cold source during ground fast charging to achieve rapid cooling of the battery pack. Summary of the Invention

[0007] To address the aforementioned issues, this invention proposes an eVTOL battery pack thermal management system based on a three-medium heat exchanger. During takeoff and level flight, it utilizes the low-temperature environment at high altitudes to achieve efficient and reliable low-energy heat dissipation through a two-phase thermosiphon cycle, while simultaneously ensuring system safety. During rapid charging on the ground, the three-medium heat exchanger module seamlessly connects to the ground cooling system, introducing a powerful external cold source to achieve rapid battery pack cooling, ensuring charging safety and efficiency.

[0008] This invention adopts the following technical solution: an eVTOL battery pack thermal management system based on a three-medium heat exchanger, comprising an onboard battery pack cooling module, a three-medium heat exchanger module, and a ground cooling system; the onboard battery pack cooling module includes a built-in battery pack cold plate, a gas pipe, a liquid pipe, and a reservoir on the liquid pipe; the built-in battery pack cold plate includes the battery pack and a liquid cooling plate, the liquid cooling plate absorbing the heat of the battery pack; the built-in battery pack cold plate, the gas pipe, the onboard coolant inlet of the three-medium heat exchanger module, the onboard coolant outlet of the three-medium heat exchanger module, the liquid pipe, and the reservoir are connected in sequence, the interior is evacuated and filled with phase change working fluid, forming a pump-free thermosiphon circulation loop, the onboard battery pack cooling module is installed on the eVTOL; the installation position of the three-medium heat exchanger module is higher than that of the built-in battery pack cold plate; The three-medium heat exchanger module includes an airborne coolant inlet, an airborne coolant outlet, a ground coolant inlet, a ground coolant outlet, an airborne coolant parallel flow flat tube, a ground coolant parallel flow flat tube, heat dissipation fins, and a cooling fan. The airborne coolant parallel flow flat tube, the ground coolant parallel flow flat tube, and the heat dissipation fins are sequentially and tightly welded to achieve indirect heat exchange. The airborne coolant inlet, the airborne coolant parallel flow flat tube, and the airborne coolant outlet are sequentially connected to form an airborne coolant channel. The ground coolant inlet, the ground coolant parallel flow flat tube, and the ground coolant outlet are sequentially connected to form a ground coolant channel. The system includes a three-medium heat exchanger module, which enables efficient heat exchange between the airborne coolant channel, the ground coolant channel, and the air. The three-medium heat exchanger module is installed on the eVTOL. The ground cooling system includes a quick-connect inlet connector, a quick-connect outlet connector, a ground water-cooled unit, a ground water pump, and ground piping. The ground piping connects the ground water-cooled unit and the ground water pump sequentially, and is detachably connected via the quick-connect inlet connector, the quick-connect outlet connector, and the ground coolant outlet, forming a ground water pump-driven circulation loop. The ground cooling system is installed on the ground.

[0009] Optionally, the gas pipe and liquid pipe are made of lightweight and flexible metal hoses or high-performance polymer pipes, used to connect the built-in battery pack cold plate, the airborne coolant inlet and outlet of the three-medium heat exchanger module, and the liquid reservoir, forming a pump-free thermosiphon circulation loop.

[0010] Optionally, the built-in battery pack cooling plate is installed inside the support structure of the eVTOL, or below the wing, fuselage, or passenger cabin or cargo hold.

[0011] Optionally, the built-in battery pack cold plate is arranged according to the contact method between the battery pack and the liquid cooling plate, which includes the liquid cooling plate contacting the upper and lower surfaces of the battery pack or the liquid cooling plate being inserted between adjacent battery cells.

[0012] Optionally, the heat exchange medium of the three-medium heat exchanger module includes airborne coolant, ground coolant, and air flowing through the heat dissipation fins.

[0013] Optionally, both the airborne coolant parallel flow flat tube and the ground coolant parallel flow flat tube of the three-medium heat exchanger module are parallel flow porous flat tube structures.

[0014] Optionally, a water pump is also provided in the thermosiphon circulation loop to form a pump-driven two-phase circulation loop.

[0015] Optionally, the heat dissipation fins are corrugated or louvered aluminum fins, placed between several parallel flat tubes.

[0016] Optionally, the cooling fan is installed upstream or downstream of the airflow direction of the heat dissipation fins to actively introduce cooling air.

[0017] Optionally, the eVTOL battery pack thermal management system is configured to operate in the following modes:

[0018] (a) During the takeoff phase of eVTOL, in the pump-free thermosiphon circulation loop, the battery heat passes sequentially through the built-in battery pack cold plate, the airborne coolant, and the airborne coolant parallel flow flat tube of the three-medium heat exchanger module, and is finally dissipated by the air passing through the heat dissipation fins and the cold energy stored in the reservoir.

[0019] (b) During the level flight phase, in the pump-free thermosiphon circulation loop, the battery heat passes sequentially through the built-in battery pack cold plate, the airborne coolant, the airborne coolant parallel flow flat tube of the three-medium heat exchanger module, and is finally dissipated by the air flowing through the heat dissipation fins.

[0020] (c) During rapid charging on the ground, the battery heat is exchanged sequentially through the built-in battery pack cold plate, the airborne coolant, the airborne coolant parallel flow flat tube of the three-medium heat exchanger module and the ground coolant parallel flow flat tube, and finally carried away by the ground cooling system.

[0021] The beneficial effects of this invention are as follows:

[0022] (1) During takeoff, the system achieves high-power heat dissipation and lightweight design by using a two-phase thermosiphon cycle consisting of an onboard battery pack cooling module and a three-medium heat exchanger module, combined with the cold energy stored in the liquid working fluid.

[0023] (2) During the level flight phase, the system adopts a two-phase thermosiphon circulation cooling method consisting of an onboard battery pack cooling module and a three-medium heat exchanger module. This method requires no additional energy consumption, improves system reliability, saves energy, and effectively reduces system weight;

[0024] (3) The three-medium heat exchanger module is the core heat exchange part of this system. It integrates two liquid-liquid heat exchange and gas-liquid heat exchange functions into a compact unit, which reduces the weight and volume of the system and is very suitable for the stringent space and weight requirements of eVTOL. During takeoff and level flight, the airborne coolant and air exchange heat. After charging on the ground or landing, it is connected to the ground cooling system through a quick connector. At this time, the system uses the synergistic heat exchange of airborne coolant, ground coolant and air to transfer the heat generated by the battery pack to the ground water-cooled unit through the ground coolant.

[0025] (4) When charging on the ground, it can continuously and efficiently dissipate the huge Joule heat generated by the battery, ensuring that the battery is charged quickly within the optimal temperature range, thereby significantly improving charging efficiency and effectively extending the battery cycle life. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of an eVTOL battery pack thermal management system based on a three-medium heat exchanger according to the present invention.

[0027] Figure 2 This is a schematic diagram of the battery pack thermal management system for the eVTOL flight phase.

[0028] Figure 3 This is a schematic diagram of the structure of a three-medium heat exchanger module;

[0029] Figure 4 This is a schematic diagram of a three-medium heat exchanger.

[0030] Figure 5 This is a schematic diagram of the parallel flow flat tubes for airborne and ground-based coolants in a three-medium heat exchanger module.

[0031] Figure 6 Schematic diagram of the installation locations of the battery pack and the three-medium heat exchanger module. Figure 1 ;

[0032] Figure 7 Schematic diagram of the installation locations of the battery pack and the three-medium heat exchanger module. Figure 2 ;

[0033] Figure 8 The contact method between the battery pack and the liquid cooling plate is intended. Figure 1 ;

[0034] Figure 9 The contact method between the battery pack and the liquid cooling plate is intended. Figure 2 ;

[0035] Figure 10 A schematic diagram of the eVTOL flight phase battery pack pump-driven two-phase cycle thermal management system.

[0036] Explanation of annotations in the image:

[0037] 1. Airborne battery pack cooling module; 1-1. Built-in battery pack cooling plate; 1-1-1. Battery pack; 1-1-2. Liquid cooling plate; 1-2. Gas pipe; 1-3. Liquid pipe; 1-4. Liquid reservoir; 1-5. Airborne water pump; 2. Three-medium heat exchanger module; 2-1. Airborne coolant inlet; 2-2. Airborne coolant outlet; 2-3. Ground coolant inlet; 2-4. Ground coolant outlet; 2-5. Airborne coolant parallel flow flat pipe; 2-6. Ground coolant parallel flow flat pipe; 2-7. Heat dissipation fins; 2-8. Cooling fan; 3. Ground cooling system; 3-1. Quick inlet connector; 3-2. Quick outlet connector; 3-3. Ground water-cooled unit equipment; 3-4. Ground water pump; 3-5. Ground piping; 4. eVTOL strut; 5. Fuselage interior. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] This invention provides an eVTOL battery pack thermal management system based on a three-medium heat exchanger, such as... Figure 1As shown, the system comprises an airborne battery pack cooling module 1, a three-medium heat exchanger module 2, and a ground cooling system 3. The airborne battery pack cooling module 1 includes a built-in battery pack cooling plate 1-1, a gas pipe 1-2, a liquid pipe 1-3, and a liquid reservoir 1-4 on the liquid pipe 1-3. The built-in battery pack cooling plate 1-1 consists of the battery pack 1-1-1 and a liquid cooling plate 1-1-2, with the liquid cooling plate 1-1-2 absorbing the heat from the battery pack 1-1-1. The airborne coolant inlet 2- of the built-in battery pack cooling plate 1-1, the gas pipe 1-2, and the three-medium heat exchanger module... 1. The airborne coolant outlet 2-2, liquid pipe 1-3, and reservoir 1-4 of the three-medium heat exchanger module are connected in sequence. The interior is evacuated and filled with phase change working fluid to form a pump-free thermosiphon circulation loop. The reservoir 1-4 on the liquid pipe 1-3 accommodates the volume expansion and contraction of the coolant due to temperature changes and can remove gas from the pipeline during system initialization, thus playing a role in cold storage and buffering. The airborne battery pack cooling module 1 is installed on the eVTOL. The installation position of the three-medium heat exchanger module 2 is higher than that of the built-in battery pack cold plate 1-1.

[0040] In this embodiment, the ground cooling system 3 includes a liquid inlet quick connector 3-1, a liquid outlet quick connector 3-2, a ground water-cooled unit 3-3, a ground water pump 3-4, and a ground pipeline 3-5. Both the liquid inlet quick connector 3-1 and the liquid outlet quick connector 3-2 have self-sealing functions. The ground pipeline 3-5 is connected in sequence to the ground water-cooled unit 3-3 and the ground water pump 3-4, and is detachably connected to the ground coolant inlet 2-3 and the ground coolant outlet 2-4 through the liquid inlet quick connector 3-1 and the liquid outlet quick connector 3-2, respectively, forming a ground water pump driven circulation loop. The ground cooling system 3 is installed on the ground.

[0041] In this embodiment, the thermosiphon circulation loop and the ground water pump drive circulation loop achieve heat exchange on the ground through the three-medium heat exchanger module 2. The three-medium heat exchanger module 2 is the core heat exchange component of this system. Based on the three-medium heat exchanger module 2, the airborne coolant channel, the ground coolant channel and the air can exchange heat with each other efficiently. The three-medium heat exchanger module 2 is installed on the eVTOL.

[0042] like Figure 2As shown, the gas pipe 1-2 and liquid pipe 1-3 are made of lightweight and flexible metal hoses or high-performance polymer pipes, used to connect the built-in battery pack cold plate 1-1, the airborne coolant inlet 2-1 and airborne coolant outlet 2-2 of the three-medium heat exchanger module 2, and the reservoir 1-4, forming a pump-free thermosiphon circulation loop, which is installed on the eVTOL; the reservoir 1-4 on the liquid pipe 1-3 is used to accommodate the volume expansion and contraction of the coolant due to temperature changes, and can remove gas in the pipeline during system initialization, playing a role in cold storage and buffering; the installation position of the three-medium heat exchanger module 2 is higher than the built-in battery pack cold plate 1-1.

[0043] like Figure 3 and Figure 4 As shown, the three-medium heat exchanger module 2 consists of an airborne coolant inlet 2-1, an airborne coolant outlet 2-2, a ground coolant inlet 2-3, a ground coolant outlet 2-4, an airborne coolant parallel flow flat tube 2-5, a ground coolant parallel flow flat tube 2-6, heat dissipation fins 2-7, and a cooling fan 2-8. The airborne coolant parallel flow flat tube 2-5, the ground coolant parallel flow flat tube 2-6, and the heat dissipation fins 2-7 are sequentially and tightly welded to achieve indirect heat exchange. The airborne coolant inlet 2-1, the airborne coolant parallel flow flat tube 2-5, and the airborne coolant outlet 2-2 are sequentially connected to form an airborne coolant channel. The ground coolant inlet 2-3, the ground coolant parallel flow flat tube 2-6, and the ground coolant outlet 2-4 are sequentially connected to form a ground coolant channel. The heat dissipation fins 2-7 are corrugated or louvered aluminum fins, placed between several parallel flow flat tubes. The cooling fan 2-8 is installed upstream or downstream of the airflow direction of the cooling fins 2-7 to actively introduce cooling air.

[0044] like Figure 5 As shown, the airborne coolant parallel flow flat tube 2-5 and the ground coolant parallel flow flat tube 2-6 of the three-medium heat exchanger module 2 are arranged together and brazed, which has high mechanical strength and heat transfer efficiency. Both types of parallel flow flat tubes adopt a parallel flow porous flat tube structure. The multiple microchannels inside the horizontal flat tube can significantly increase the heat exchange area and effectively reduce the flow resistance.

[0045] like Figure 6 and Figure 7 As shown, the three-medium heat exchanger module 2 is installed according to the position of the built-in battery pack cold plate 1-1. The built-in battery pack cold plate 1-1 can be installed inside the support structure of the eVTOL or on the wing. The installation position of the three-medium heat exchanger module 2 is higher than the built-in battery pack cold plate 1-1 to facilitate air circulation.

[0046] In this embodiment, the built-in battery pack cold plate 1-1 is directly in contact with the battery pack 1-1-1 by the liquid cooling plate 1-1-2 for efficient heat conduction. The liquid cooling plate 1-1-2 is made of aluminum alloy or copper alloy with high thermal conductivity and has microchannels inside to increase the heat exchange area. The contact method between the liquid cooling plate 1-1-2 and the battery pack 1-1-1 can be selected according to the structure of the battery pack 1-1-1.

[0047] It should be noted that the built-in battery pack cold plate 1-1 is arranged according to the contact method between the battery pack 1-1-1 and the liquid cooling plate 1-1-2. The contact method includes the liquid cooling plate 1-1-2 contacting the upper and lower surfaces of the battery pack 1-1-1 or the liquid cooling plate 1-1-2 being inserted between adjacent battery cells.

[0048] In one implementation, such as Figure 8 As shown, the liquid cooling plate 1-1-2 is attached as a whole to one or more outer surfaces of the battery pack 1-1-1, as shown above and below, and thermal grease is applied between the two to reduce contact thermal resistance.

[0049] In another functional implementation, such as Figure 9 As shown, the liquid cooling plate 1-1-2 is designed as a multi-sheet structure, which is directly inserted between adjacent cells inside the battery pack 1-1-1 to achieve more direct and efficient cooling.

[0050] The workflow and typical embodiments of the present invention are as follows:

[0051] When the eVTOL takes off, the ground cooling system 3 is not connected. The high-power heat generated by the battery pack 1-1-1 is absorbed by the onboard coolant within the built-in battery pack cold plate 1-1. The heated onboard coolant decreases in density and, driven by thermosiphon, rises naturally along the gas pipe 1-2, flowing into the higher-positioned three-medium heat exchanger module 2. Here, heat is transferred to the surrounding airflow through the onboard coolant parallel flow flat pipe 2-5 and the heat dissipation fins 2-7. The cooled onboard coolant increases in density and, under gravity, flows back along the liquid pipe 1-3 to the reservoir 1-4 and the built-in battery pack cold plate 1-1, completing the thermosiphon cycle. During this process, the system fully utilizes the cold energy stored in the liquid working fluid and the efficient heat transfer characteristics of two-phase flow to achieve high-power heat dissipation. In this mode, the cooling fan 2-8 can be activated as needed.

[0052] When the eVTOL is in level flight, the ground cooling system 3 is not connected. The heat generated by the battery pack 1-1-1 is absorbed by the onboard coolant within the built-in battery pack cold plate 1-1. The heated onboard coolant decreases in density and, driven by thermosiphon, rises naturally along the gas pipe 1-2, flowing into the higher-positioned three-medium heat exchanger module 2. Here, heat is transferred to the outside airflow through the onboard coolant parallel flow flat pipe 2-5 and the heat dissipation fins 2-7. The cooled onboard coolant increases in density and, under gravity, flows back along the liquid pipe 1-3 to the reservoir 1-4 and the built-in battery pack cold plate 1-1, completing the thermosiphon cycle. In this mode, the cooling fan 2-8 can be activated as needed.

[0053] When the eVTOL performs ground-based fast charging, the ground cooling system 3 is connected via quick-connect fittings 3-1 and 3-2. The heat generated by the battery pack 1-1-1 is primarily transferred to the ground coolant circulated by the ground water pump 3-4 and the air flowing through the heat dissipation fins 2-7 as it flows through the three-medium heat exchanger module 2. This ground coolant, carrying a large amount of heat, is ultimately cooled to the set temperature in the ground water-cooled unit 3-3. This mode greatly utilizes the ground power and its powerful cooling capacity, solving the heat dissipation bottleneck under high-temperature ground environments and high-rate charging, thus achieving rapid cooling of the battery pack 1-1-1.

[0054] like Figure 10 As shown, in another embodiment of the eVTOL battery pack thermal management system based on a three-medium heat exchanger, to ensure stable and reliable circulation power under all operating conditions, especially when the thermosiphon circulation driving force is insufficient or the heat dissipation requirements are stringent, the onboard battery pack cooling module 1 has been optimized. In the thermosiphon circulation, an onboard water pump 1-5 is added. The built-in battery pack cold plate 1-1, gas pipe 1-2, the onboard coolant inlet 2-1 and outlet 2-2 of the three-medium heat exchanger module, liquid pipe 1-3, reservoir 1-4, and onboard water pump 1-5 are connected sequentially to form an onboard pump-driven two-phase circulation loop. The onboard water pump 1-5 is preferably a low-power, long-life DC brushless motor pump, which is connected in series between the outlet of the reservoir 1-4 and the inlet of the built-in battery pack cold plate 1-1 via the liquid pipe 1-3. This provides a stable and controllable forced driving force for the entire circulation loop. This driving force, combined with the natural driving force generated by the thermosiphon effect, overcomes the system's flow resistance, ensuring that the airborne coolant circulates according to design requirements under various conditions.

[0055] The above description is merely a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For those skilled in the art, any obvious modifications, equivalent substitutions, or improvements made based on the technical teachings of the present invention without departing from the principles and concept of the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be defined by the appended claims.

Claims

1. An eVTOL battery pack thermal management system based on a triple medium heat exchanger, characterized by: It comprises an airborne battery pack cooling module (1), a three-medium heat exchanger module (2) and a ground cooling system (3); The airborne battery pack cooling module (1) comprises an internal battery pack cooling plate (1-1), a gas pipe (1-2), a liquid pipe (1-3) and a liquid reservoir (1-4) on the liquid pipe (1-3); the internal battery pack cooling plate (1-1) comprises a battery pack (1-1-1) and a liquid cooling plate (1-1-2), and the liquid cooling plate (1-1-2) is used for absorbing heat of the battery pack (1-1-1); the internal battery pack cooling plate (1-1), the gas pipe (1-2), the airborne cooling liquid inlet (2-1) of the three-medium heat exchanger module (2), the airborne cooling liquid outlet (2-2) of the three-medium heat exchanger module (2), the liquid pipe (1-3) and the liquid reservoir (1-4) are sequentially connected, vacuumized inside and filled with phase change working medium, thereby forming a pump-free thermosyphon circulation loop, and the airborne battery pack cooling module (1) is installed on an eVTOL; the installation position of the three-medium heat exchanger module (2) is higher than that of the internal battery pack cooling plate (1-1); The three-medium heat exchanger module (2) comprises an airborne cooling liquid inlet (2-1), an airborne cooling liquid outlet (2-2), a ground cooling liquid inlet (2-3), a ground cooling liquid outlet (2-4), an airborne cooling liquid parallel flow flat tube (2-5), a ground cooling liquid parallel flow flat tube (2-6), a heat dissipation fin (2-7) and a heat dissipation fan (2-8); the airborne cooling liquid parallel flow flat tube (2-5), the ground cooling liquid parallel flow flat tube (2-6) and the heat dissipation fin (2-7) are sequentially tightly welded to realize wall-type heat exchange; the airborne cooling liquid inlet (2-1), the airborne cooling liquid parallel flow flat tube (2-5) and the airborne cooling liquid outlet (2-2) are sequentially communicated to form an airborne cooling liquid channel; the ground cooling liquid inlet (2-3), the ground cooling liquid parallel flow flat tube (2-6) and the ground cooling liquid outlet (2-4) are sequentially communicated to form a ground cooling liquid channel; the three-medium heat exchanger module (2) can realize efficient heat exchange among the airborne cooling liquid channel, the ground cooling liquid channel and air; the three-medium heat exchanger module (2) is installed on an eVTOL; The ground cooling system (3) comprises a liquid inlet quick connector (3-1), a liquid outlet quick connector (3-2), a ground water cooling unit (3-3), a ground water pump (3-4) and a ground pipeline (3-5); the ground pipeline (3-5) sequentially connects the ground water cooling unit (3-3) and the ground water pump (3-4), and is detachably connected with the ground cooling liquid inlet (2-3) and the ground cooling liquid outlet (2-4) through the liquid inlet quick connector (3-1) and the liquid outlet quick connector (3-2), thereby forming a ground water pump driven circulation loop; the ground cooling system (3) is installed on the ground.

2. The three-medium heat exchanger based thermal management system for eVTOL battery pack according to claim 1, wherein: The gas pipe (1-2) and the liquid pipe (1-3) are light and flexible metal hoses or high-performance polymer pipes, which are used to connect the built-in battery pack cold plate (1-1), the on-board cooling liquid inlet (2-1) and the on-board cooling liquid outlet (2-2) of the three-medium heat exchanger module, and the liquid reservoir (1-4), and form a pump-free thermosyphon circulation loop.

3. The three-medium heat exchanger based thermal management system for eVTOL battery pack according to claim 1, wherein: The built-in battery pack cold plate (1-1) is installed inside the support structure of the eVTOL, or below the wings, the middle of the fuselage, or the passenger cabin or cargo cabin.

4. The three-medium heat exchanger based thermal management system for eVTOL battery pack according to claim 1, wherein: The built-in battery pack cold plate (1-1) is arranged according to the contact mode of the battery pack (1-1-1) and the liquid cooling plate (1-1-2), which includes the upper and lower surfaces of the liquid cooling plate (1-1-2) contacting the battery pack (1-1-1) or the liquid cooling plate (1-1-2) being inserted between adjacent battery cells.

5. The three-medium heat exchanger based eVTOL battery pack thermal management system of claim 1, wherein: The heat exchange medium of the three-medium heat exchanger module (2) includes on-board cooling liquid, ground cooling liquid, and air flowing through the heat dissipation fins (2-7).

6. The three-medium heat exchanger based eVTOL battery pack thermal management system of claim 1, wherein: The on-board cooling liquid parallel flow flat tube (2-5) and the ground cooling liquid parallel flow flat tube (2-6) of the three-medium heat exchanger module (2) are both parallel flow porous flat tube structures.

7. The three-medium heat exchanger based thermal management system for eVTOL battery pack according to claim 1, wherein: A water pump is also provided in the thermosyphon circulation loop to form a pump-driven two-phase circulation loop.

8. The three-medium heat exchanger based thermal management system for eVTOL battery pack according to claim 1, wherein: The heat dissipation fins (2-7) are corrugated or louvered aluminum fins, which are placed between several parallel flow flat tubes.

9. The three-medium heat exchanger based eVTOL battery pack thermal management system of claim 1, wherein: The cooling fan (2-8) is installed upstream or downstream of the air flow direction of the heat dissipation fins (2-7) to actively introduce cooling air.

10. The three-medium heat exchanger based thermal management system for eVTOL battery pack according to claim 1, wherein: The eVTOL battery pack thermal management system is configured in the following modes: (a) In the take-off stage of the eVTOL, the battery heat in the pump-free thermosyphon circulation loop is sequentially exchanged through the built-in battery pack cold plate (1-1), the on-board cooling liquid, the on-board cooling liquid parallel flow flat tube of the three-medium heat exchanger module (2), and finally the air through the heat dissipation fins (2-7) and the cold energy stored in the liquid reservoir (1-4); (b) In the cruising stage, the battery heat in the pump-free thermosyphon circulation loop is sequentially exchanged through the built-in battery pack cold plate (1-1), the on-board cooling liquid, the on-board cooling liquid parallel flow flat tube of the three-medium heat exchanger module (2), and finally the air flowing through the heat dissipation fins (2-7); (c) In the ground rapid charging, the battery heat is sequentially exchanged through the built-in battery pack cold plate (1-1), the on-board cooling liquid, the on-board cooling liquid parallel flow flat tube and the ground cooling liquid parallel flow flat tube of the three-medium heat exchanger module (2), and finally taken away by the ground cooling system (3).

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