Thermal management system, battery system, and electric aircraft

Abstract

A thermal management system, a battery system and an electric aircraft are provided. The thermal management system includes a water pump, a cooling unit, a first expansion valve, a compressor, a second expansion valve and a condenser. The water pump, the cooling unit and a battery pack are connected in sequence via pipelines to form a first loop, and a first heat exchange medium is capable of circulating in the first loop to transfer heat generated by the battery pack to the cooling unit via the first heat exchange medium. The first heat exchange medium and a second heat exchange medium are capable of exchanging heat in the cooling unit for transferring the heat absorbed by the first heat exchange medium to the second heat exchange medium. The cooling unit, the compressor, the condenser and the first expansion valve are connected in sequence via pipelines to form a second loop, and the second heat exchange medium is capable of circulating in the second loop to transfer the heat absorbed by the second heat exchange medium to the condenser. The second expansion valve is arranged in a first branch, and two ends of the first branch are connected to an upstream side and a downstream side of the compressor, respectively.

Description

Technical Field

[0001] This application relates to the field of electric aircraft technology, and in particular to a thermal management system, a battery system, and an electric aircraft. Background Technology

[0002] With the development of the low-altitude economy, electric vertical takeoff and landing (eVTOL) aircraft are gradually being put into commercial operation, and their application scenarios include, but are not limited to, low-altitude sightseeing, urban passenger transport, cargo transport, emergency medical services, and rescue services.

[0003] Electric vertical takeoff and landing (EVTOL) aircraft generate a significant amount of heat during operation, particularly from their battery systems during takeoff, cruise, and landing. Failure to effectively manage and dissipate this heat can lead to a continuous rise in battery cell temperature and a reduction in discharge power, ultimately affecting the normal function and performance of the electric aircraft. In extreme cases, the continued accumulation of heat can even trigger thermal runaway in the battery system.

[0004] Because the battery pack itself has good thermal insulation capabilities, the heat generated inside it usually cannot be directly exchanged with the external environment, but needs to be transferred through a thermal management system. However, in low-temperature environments (e.g., ambient temperatures below zero degrees Celsius), the cooling function of ordinary thermal management systems cannot operate normally, causing their thermal management capabilities to drop significantly or even fail in low-temperature environments. Therefore, there is an urgent need to improve the thermal management system of electric aircraft to adapt to low-temperature environments. Utility Model Content

[0005] This application is made in view of the aforementioned state of the prior art. The purpose of this application is to provide a thermal management system, thermal management method, battery system, and electric aircraft suitable for cryogenic environments.

[0006] This application provides a thermal management system for the thermal management of a battery pack in an electric aircraft. The system includes a water pump, a cooling section, a first expansion valve, a compressor, a second expansion valve, and a condenser. The water pump, the cooling section, and the battery pack are sequentially connected via pipelines to form a first loop. A first heat exchange medium circulates within the first loop to transfer heat generated by the battery pack to the cooling section for discharge. The first and second heat exchange media exchange heat within the cooling section, transferring heat absorbed by the first heat exchange medium to the second heat exchange medium. The cooling section, the compressor, the condenser, and the first expansion valve are sequentially connected via pipelines to form a second loop. The second heat exchange medium circulates within the second loop to discharge heat absorbed by the second heat exchange medium via the condenser. The second expansion valve is located on a first branch, with both ends of the first branch connected to the upstream and downstream sides of the compressor, respectively.

[0007] In one possible implementation, the thermal management system further includes a liquid storage section disposed in a second branch connected to the first circuit, enabling the liquid storage section to store the first heat exchange medium in the first circuit; and / or further includes a first heating section disposed in the first circuit and upstream of the battery pack, for heating the first heat exchange medium that will enter the battery pack.

[0008] In one possible implementation, the thermal management system further includes a second heating unit disposed on the first branch and downstream of the second expansion valve, located between the second expansion valve and the compressor.

[0009] In one possible implementation, the thermal management system further includes one or more first temperature sensors, one or more second temperature sensors, one or more pressure sensors, and one or more temperature-pressure sensors, wherein the first temperature sensor is disposed in the first loop, and the second temperature sensor, the pressure sensor, and the temperature-pressure sensor are disposed in the second loop.

[0010] In one possible implementation, the first heat exchange medium is an ethylene glycol solution, and / or the second heat exchange medium is tetrafluoroethane.

[0011] In one possible implementation, the inlet of the second expansion valve is connected between the compressor and the condenser, and the outlet of the second expansion valve is connected between the cooling section and the compressor.

[0012] In one possible implementation, the thermal management system further includes a gas-liquid separator disposed in the second circuit and between the cooling section and the compressor to prevent or reduce the entry of the liquid second heat exchange medium into the compressor.

[0013] This application also provides a thermal management method for the thermal management of a battery pack in an electric aircraft. This method is applicable to the aforementioned thermal management system. The thermal management method includes: S1: opening the second expansion valve to allow a portion of the second heat exchange medium to circulate between the first branch and the compressor, thereby increasing the pressure and temperature of the second heat exchange medium in the second circuit; S2: after the pressure and temperature of the second heat exchange medium in the second circuit reach normal operating requirements, opening the first expansion valve again, closing the second expansion valve, or adjusting the opening of the second expansion valve to regulate the flow rate of the second heat exchange medium, causing the compressor to drive the second heat exchange medium to circulate in the second circuit, so that the first heat exchange medium and the second heat exchange medium exchange heat in the cooling section.

[0014] This application also provides a battery system including a battery pack and the aforementioned thermal management system for electric aircraft.

[0015] In one possible implementation, the battery pack is a distributed battery pack, which includes multiple cell groups, each of which is independently connected to the first circuit.

[0016] This application also provides an electric aircraft that includes the aforementioned thermal management system.

[0017] The thermal management system, thermal management method, battery system, and electric aircraft provided in this application are applicable to low-temperature environments, such as below zero degrees Celsius. Based on the dual-loop design of the first loop and the second loop, and the first branch connecting the upstream and downstream sides of the compressor, thermal management of the battery pack can be achieved at lower ambient temperatures, ensuring that the battery pack of the electric aircraft can operate safely and stably in low-temperature environments, thereby improving the environmental adaptability of the electric aircraft. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the battery system of an electric aircraft according to one embodiment of this application.

[0019] Figure 2 This is a schematic diagram of a first variation of the battery system of an electric aircraft according to one embodiment of this application.

[0020] Figure 3 This is a schematic diagram of a second variation of the battery system of an electric aircraft according to one embodiment of this application.

[0021] Explanation of reference numerals in the attached figures

[0022] 10 Water Pumps

[0023] 20 Cooling section

[0024] 30 First heating section

[0025] 40 Liquid storage part

[0026] 50 First expansion valve

[0027] 60 compressor

[0028] 71 Second expansion valve

[0029] 72 Second heating section

[0030] 73 Gas-liquid separator

[0031] 80 Condenser

[0032] 81 Fan

[0033] 91 First Temperature Sensor

[0034] 92 Second Temperature Sensor

[0035] 93 Pressure Sensor

[0036] 94 Temperature and pressure sensors

[0037] 100 battery pack

[0038] 110 First Cell Pack

[0039] 120 Second Cell Pack

[0040] 130 Third Cell Pack Detailed Implementation

[0041] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.

[0042] Embodiments of this application provide a thermal management system (hereinafter, sometimes simply referred to as a thermal management system) that can be used to perform thermal management (especially cooling) of the battery pack of an electric aircraft at low ambient temperatures (e.g., below zero degrees Celsius).

[0043] The term "lower ambient temperature" as used in this application refers to a temperature close to or below the minimum normal operating temperature of a conventional thermal management system / refrigeration system. For example, a low temperature can be below -7 degrees Celsius. The term "normal temperature environment" as used in this application refers to the normal operating temperature range of a conventional thermal management system / refrigeration system. For example, a normal temperature can be above -7 degrees Celsius.

[0044] It is understandable that even at the aforementioned low temperatures, the battery pack will still generate a large amount of heat that cannot be dissipated or discharged when it is working. As a result, the conventional thermal management system (air conditioning system) will experience excessive condensation of the refrigerant due to the low temperature environment, resulting in a drop in system pressure and the refrigerant saturation temperature approaching or even falling below the ambient temperature. This will severely affect the cooling capacity of the conventional thermal management system and may even prevent it from starting up and operating normally.

[0045] Specifically, such as Figure 1 and Figure 2 As shown, the thermal management system may include a water pump 10, a cooling unit 20, a first expansion valve 50, a compressor 60, and a condenser 80. The water pump 10, cooling unit 20, and battery pack 100 can be sequentially connected via pipelines to form a first loop (a circulating flow path formed by connecting the beginning and end). A first heat exchange medium can be filled into the pipelines of the first loop, and the first heat exchange medium can circulate within the first loop to transfer the heat energy generated by the battery pack 100 to the cooling unit 20 and then discharged from the first loop. The flow direction of the first heat exchange medium within the first loop can be sequentially flowing through the battery pack 100, water pump 10, cooling unit 20, and battery pack 100, thereby forming a flow circulation.

[0046] Preferably, the first heat exchange medium can be an ethylene glycol solution. Ethylene glycol solution has a low freezing point (down to -60 degrees Celsius), allowing the first loop to operate at lower ambient temperatures and preventing damage to the pipeline due to liquid freezing. Simultaneously, ethylene glycol solution also has a high specific heat capacity and good thermal conductivity.

[0047] Preferably, the water pump 10 can be an electronic water pump. The electronic water pump is electrically driven to transport liquids. Compared with traditional water pumps, it can more accurately control the flow of heat exchange medium and improve temperature management efficiency.

[0048] When the first heat exchange medium passes through the battery pack 100, it can absorb the heat released by the battery pack 100 during operation. The cooling section 20 can cool the first heat exchange medium passing through it, that is, dissipate the heat absorbed by the first heat exchange medium. Furthermore, the first heat exchange medium can transfer the heat absorbed by it to the second heat exchange medium within the cooling section 20. That is, the first heat exchange medium and the second heat exchange medium can exchange heat within the cooling section 20, so that the heat generated by the battery pack 100 is discharged from the first circuit.

[0049] The cooling section 20, compressor 60, condenser 80, and first expansion valve 50 can be sequentially connected via pipelines to form a second circuit. A second heat exchange medium can be filled into the pipelines of the second circuit, and this second heat exchange medium can circulate within the second circuit to discharge the heat absorbed by the second heat exchange medium through the condenser 80. The flow direction of the second heat exchange medium within the second circuit can be a sequential flow through the cooling section 20, compressor 60, condenser 80, first expansion valve 50, and cooling section 20 to form a circulation loop.

[0050] Specifically, the cooling section 20 may include a first heat exchange medium channel and a second heat exchange medium channel. The first heat exchange medium channel may be connected to a first circuit, and the second heat exchange medium channel may be connected to a second circuit. The first heat exchange medium channel and the second heat exchange medium channel are not directly connected, that is, no mass exchange occurs between them. The first heat exchange medium channel and the second heat exchange medium channel may be adjacent to each other to facilitate heat exchange between them.

[0051] The compressor 60 draws in the second heat exchange medium, compresses it, and then discharges it. The pressure and temperature of the second heat exchange medium after processing by the compressor 60 will increase, meaning the compressor 60 can increase the system pressure in the second circuit. The second heat exchange medium (usually a high-pressure gas) processed by the compressor 60 can release heat and condense into a liquid state in the condenser 80. The heat generated by the battery pack 100 is released to the external environment through the condenser 80. The second heat exchange medium (usually a high-pressure liquid) condensed in the condenser 80 can be depressurized and cooled by the first expansion valve 50 before entering the cooling section 20 to absorb heat from the first heat exchange medium. The second heat exchange medium (usually a low-pressure gas) that has absorbed heat can then enter the compressor 60, forming a recycling cycle for the second heat exchange medium.

[0052] Optionally, the thermal management system may also include a fan 81, which may be adjacent to the condenser 80, for blowing out the heat released by the second heat exchange medium at the condenser 80, thereby improving the heat dissipation efficiency of the condenser 80.

[0053] To adapt to lower ambient temperatures, the thermal management system may also include a second expansion valve 71. The second expansion valve 71 can be located in the first branch, with its two ends connected to the upstream and downstream sides of the compressor 60, respectively. At low ambient temperatures, the second circuit may fail to open and operate normally due to excessively low pressure. In this case, the second expansion valve 71 can be opened first, allowing the compressor 60 to compress (heat and pressurize) the second heat exchange medium in the first branch, thereby rapidly increasing the pressure and temperature within the second circuit, enabling the second circuit to overcome the low temperature and begin operation.

[0054] Preferably, the inlet of the second expansion valve 71 (or the inlet of the first branch) can be connected between the compressor 60 and the condenser 80, and the outlet of the second expansion valve 71 (or the outlet of the first branch) can be connected between the cooling section 20 and the compressor 60.

[0055] Preferably, the first expansion valve 50 and the second expansion valve 71 can be electronic expansion valves. Electronic expansion valves may include controllers, actuators, sensors, etc., and can have functions such as controlling flow path on / off, throttling, and pressure reduction. The specific structures of the first expansion valve 50 and the second expansion valve 71 can differ. It is understood that the specific structures of the first expansion valve 50 and the second expansion valve 71 can be determined according to the different on / off, throttling, and pressure reduction requirements corresponding to the second circuit and the first branch. For example, the first expansion valve 50 can have better throttling, pressure reduction, and temperature reduction capabilities; the second expansion valve 71 can have better on / off control capabilities, and compared to the first expansion valve 50, the second expansion valve 71 can have a higher flow capacity to meet the needs of rapidly increasing the pressure and temperature of the second circuit system.

[0056] Preferably, the thermal management system may further include a liquid storage unit 40, which may be located in the second branch and connected to the first loop, enabling the liquid storage unit 40 to store the first heat exchange medium in the first loop. As the temperature of the first loop changes, the volume of the first heat exchange medium within the first loop may change due to thermal expansion and contraction, thereby causing changes in the internal pressure of the first loop. The liquid storage unit 40 can balance the volume changes of the first heat exchange medium; that is, it stores a portion of the first heat exchange medium when its volume increases and releases a portion when its volume decreases, thereby maintaining a relatively stable internal pressure in the first loop.

[0057] Preferably, the thermal management system may further include a first heating unit 30, which may be disposed in the first circuit and upstream of the battery pack 100 (in the flow direction of the first heat exchange medium in the first circuit), for heating the first heat exchange medium that will enter the battery pack 100. In some cases, such as when starting the battery pack 100 in a low-temperature environment, it may be necessary to heat the battery pack 100 first. Providing the first heating unit 30 can heat the first heat exchange medium that will enter the battery pack 100, thereby achieving heating of the battery pack.

[0058] Preferred, such as Figure 2As shown, the thermal management system may further include a second heating unit 72, which may be located in the first branch and downstream of the second expansion valve 71 (in the flow direction of the second heat exchange medium in the first branch). When the aforementioned first branch is started at a lower temperature, the compressor 60 may have a larger operating load and speed due to the lower temperature of the second heat exchange medium. Providing the second heating unit 72 to heat the second heat exchange medium entering the compressor 60 can reduce the operating load and speed of the compressor 60, thereby reducing the operating noise of the compressor 60 in low-temperature environments.

[0059] The thermal management system may also include one or more of the following: a first temperature sensor 91, a second temperature sensor 92, a pressure sensor 93, and a temperature and pressure sensor 94.

[0060] The first temperature sensor 91 can be disposed in the first circuit. For example, the first temperature sensor 91 can be disposed upstream and / or downstream of the battery pack 100 to monitor the temperature of the battery pack 100 and the first heat exchange medium.

[0061] The second temperature sensor 92 can be disposed in the second circuit. For example, the second temperature sensor 92 can be disposed upstream and / or downstream of the compressor 60 to monitor the temperature of the second heat exchange medium.

[0062] Pressure sensor 93 can be located in the second circuit. For example, pressure sensor 93 can be located upstream of compressor 60 to monitor the pressure of the second heat exchange medium.

[0063] Temperature and pressure sensor 94 can be installed in the second loop. For example, temperature and pressure sensor 94 can be installed downstream of condenser 80 to monitor the pressure and temperature of the second heat exchange medium.

[0064] Preferably, the second heat exchange medium can be tetrafluoroethane R134a.

[0065] The operation of the above-mentioned thermal management system will be described below as an example.

[0066] In a normal temperature environment (above -7 degrees Celsius), when the battery pack 100 requires cooling, the water pump 10 can be turned on, driving the flow of the first heat exchange medium. The compressor 60 is also turned on, driving the flow of the second heat exchange medium. The first and second heat exchange media exchange heat in the cooling section 20. During this process, the second expansion valve 71 remains closed, and the first branch is not connected to the compressor 60.

[0067] In low-temperature environments (e.g., -7 degrees Celsius), when the battery pack 100 requires cooling, the second expansion valve 71 is first opened to circulate a portion of the second heat exchange medium between the first branch and the compressor 60. This process gradually increases the pressure and temperature of the second heat exchange medium in the second circuit. Once the second circuit meets the pressure and temperature requirements for normal operation, the first expansion valve 50 is then opened, allowing the compressor 60 to drive the second heat exchange medium to flow throughout the entire second circuit, thereby enabling heat exchange between the first and second heat exchange media in the cooling section 20.

[0068] Furthermore, such as Figure 3 As shown, the thermal management system may further include a gas-liquid separator 73, which can be installed in the second loop. The gas-liquid separator 73 separates the gas and liquid in the second heat exchange medium entering it, allowing the gaseous second heat exchange medium to enter the compressor 60, while the liquid second heat exchange medium can remain in the gas-liquid separator 73. This prevents or reduces the amount of liquid second heat exchange medium entering the compressor 60, extending the service life of the compressor 60. It is understood that the compressor 60 cannot compress liquids, and liquid entering the compressor may damage compression components such as valves and pistons (this phenomenon is also known as "liquid slugging").

[0069] Specifically, the gas-liquid separator 73 can be located upstream of the compressor 60, that is, between the cooling section 20 and the compressor 60, to prevent or reduce the entry of the liquid second heat exchange medium into the compressor 60. The gas-liquid separator 73 is mainly used to process the liquid or gas-liquid mixed state of the second heat exchange medium in the second circuit (from the cooling section 20 to the compressor 60) under low-temperature conditions. Under normal temperature conditions, the second heat exchange medium in the second circuit (from the cooling section 20 to the compressor 60) mainly exists in the form of low-pressure gas, requiring (or essentially requiring) gas-liquid separation by the gas-liquid separator 73.

[0070] It is understandable that during the initial period after the thermal management system starts up under low-temperature conditions, liquid second heat exchange medium can be collected in the gas-liquid separator 73. This liquid second heat exchange medium will gradually transform into gaseous second heat exchange medium as the temperature and pressure in the second loop rise. Therefore, the gas-liquid separator 73 does not need to be equipped with a drain structure.

[0071] Preferably, the gas-liquid separator 73 can be a gravity settling type gas-liquid separator. This type of gas-liquid separator uses a gravity field to separate liquids and gases, and can remain operational throughout the entire operation period of the thermal management system without requiring separate control of its on / off timing. That is, the gas-liquid separator 73 can primarily function during the initial period of startup in a low-temperature environment; under other operating conditions, the gas-liquid separator 73 can act as a safety device to prevent liquid slugging.

[0072] It is understood that the thermal management system provided in this embodiment can not only perform thermal management for the battery pack of the electric aircraft, but also exchange heat with other equipment of the electric aircraft that requires thermal management. For example, the passenger cabin and / or cockpit of the electric aircraft may be equipped with an air conditioning system, and this thermal management system can also be connected to the air conditioning system and exchange heat with the air conditioning system to help regulate the temperature of the passenger cabin and / or cockpit.

[0073] Based on the aforementioned thermal management system, embodiments of this application also provide a thermal management method suitable for thermal management of battery packs at low temperatures. It is applicable to the aforementioned thermal management system, and the thermal management method includes:

[0074] S1: Open the second expansion valve 71 to allow part of the second heat exchange medium to circulate between the first branch and the compressor 60, so as to increase the pressure and temperature of the second heat exchange medium in the second circuit;

[0075] S2: After the pressure and temperature of the second heat exchange medium in the second circuit reach the normal operating requirements, the first expansion valve 50 is opened and the second expansion valve 71 is closed or the opening of the second expansion valve 71 is adjusted to regulate the flow rate of the second heat exchange medium through the first branch, so that the compressor 60 drives the second heat exchange medium to circulate in the second circuit, so that the first heat exchange medium and the second heat exchange medium form a heat exchange in the cooling section 20.

[0076] It is understandable that, since the operation of the first circuit is not easily affected by low temperatures, the start-up time of the first circuit in low-temperature environments can be more flexible.

[0077] Embodiments of this application also provide a battery system suitable for electric aircraft, which may include the aforementioned thermal management system for electric aircraft and a battery pack 100.

[0078] Preferably, the battery pack 100 can be a distributed battery pack, which may include multiple cell groups. For example, Figure 1 and Figure 2 As shown, the battery pack 100 may include a first cell group 110, a second cell group 120, and a third cell group 130. Each cell group may include one or more cells.

[0079] Inside the battery pack 100, multiple cell groups can form a parallel structure, allowing each cell group to be independently connected to the first circuit. This enables the first heat exchange medium to flow through each cell group in parallel rather than sequentially through multiple cell groups, which is beneficial for each cell group to have the same or similar thermal management effect.

[0080] The aforementioned thermal management system and battery system for electric aircraft are particularly suitable for electric vertical takeoff and landing (EVTOL) aircraft; however, their application to electric aircraft is not limited to this.

[0081] This application also provides an electric aircraft, which may include the aforementioned thermal management system and / or battery system of the electric aircraft.

[0082] The thermal management system, battery system, and electric aircraft provided in the foregoing embodiments of this application are particularly suitable for use in low-temperature environments, but this does not mean that the technical solution is limited to use in low-temperature environments.

[0083] The following is a brief description of some of the beneficial effects of the above-described embodiments of this application.

[0084] The thermal management system, thermal management method, battery system, and electric aircraft provided by the embodiments of this application are based on a dual-loop design of a first loop and a second loop, as well as a first branch connecting the upstream and downstream sides of the compressor. This enables thermal management of the battery pack at lower ambient temperatures, ensuring that the battery pack of the electric aircraft can operate safely and stably in low-temperature environments, thereby improving the environmental adaptability of the electric aircraft.

[0085] It is understood that, in this application, when the number of parts or components is not specifically limited, the number can be one or more, where multiple refers to two or more. For cases where the number of parts or components shown in the drawings and / or described in the specification is, for example, two, three, four, etc., this specific number is generally exemplary and not restrictive, and can be understood as multiple, i.e., two or more; however, this does not mean that this application excludes the case of one.

[0086] It should be understood that the above embodiments are merely exemplary and are not intended to limit this application. Those skilled in the art can make various modifications and changes to the above embodiments under the teachings of this application without departing from the scope of this application.

Claims

1. A thermal management system for thermal management of a battery pack of an electric aircraft, characterized in that, Includes a water pump, cooling unit, first expansion valve, compressor, second expansion valve, and condenser. The water pump, the cooling unit, and the battery pack are connected sequentially via pipelines to form a first loop. A first heat exchange medium can circulate within the first loop to transfer the heat energy generated by the battery pack to the cooling unit for discharge. The first heat exchange medium and the second heat exchange medium can exchange heat within the cooling section, transferring the heat absorbed by the first heat exchange medium to the second heat exchange medium. The cooling unit, the compressor, the condenser, and the first expansion valve are connected in sequence via pipelines to form a second circuit. The second heat exchange medium can circulate within the second circuit to discharge the heat absorbed by the second heat exchange medium through the condenser. The second expansion valve is located in the first branch, and the two ends of the first branch are respectively connected to the upstream side and the downstream side of the compressor.

2. The thermal management system of claim 1, wherein, It also includes a liquid storage section, which is disposed in a second branch connected to the first circuit, so that the liquid storage section can store the first heat exchange medium in the first circuit; and / or It also includes a first heating element, which is disposed in the first circuit and upstream of the battery pack, for heating the first heat exchange medium that will enter the battery pack.

3. The thermal management system of claim 1, wherein, It also includes a second heating unit, which is disposed in the first branch and downstream of the second expansion valve, located between the second expansion valve and the compressor.

4. The thermal management system of claim 1, wherein, It also includes one or more first temperature sensors, one or more second temperature sensors, one or more pressure sensors, and one or more temperature and pressure sensors. The first temperature sensor is installed in the first circuit. The second temperature sensor, the pressure sensor, and the temperature-pressure sensor are disposed in the second circuit.

5. The thermal management system of claim 1, wherein, The first heat exchange medium is an ethylene glycol solution, and / or the second heat exchange medium is tetrafluoroethane.

6. The thermal management system of claim 1, wherein, The inlet of the second expansion valve is connected between the compressor and the condenser, and the outlet of the second expansion valve is connected between the cooling section and the compressor.

7. The thermal management system of claim 1, wherein, It also includes a gas-liquid separator, which is disposed in the second circuit and between the cooling section and the compressor, to prevent or reduce the entry of the liquid second heat exchange medium into the compressor.

8. A battery system characterized by, Includes a battery pack and a thermal management system for the electric aircraft according to any one of claims 1 to 6.

9. The battery system of claim 8, wherein, The battery pack is a distributed battery pack, which includes multiple cell groups, each of which is independently connected to the first circuit.

10. An electrically powered aircraft, characterized in that, The thermal management system includes any one of claims 1 to 7.

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