System and method for cooling an electric aircraft

Abstract

The invention relates to a system and method for cooling an electric aircraft. The system includes an electronic device, a housing, at least one fin, and at least one pulsating heat pipe. The electronic device may generate heat. The electronic device may be housed within the housing. The fins may be attached to the outer wall of the housing. The pulsating heat pipe can be embedded into the fins, so that the evaporator part of the pulsating heat pipe is closest to a heat source, and the condenser part of the pulsating heat pipe is farthest from the heat source. The pulsating heat pipe can also be arranged in the shell. In some embodiments, the housing may have a plurality of slots. The fins may be shaped such that a single fin may slide into a pair of slots and rest against the housing, with pulsating heat pipes may be embedded within the fins.

Description

Technical Field

[0001] The present disclosure relates to systems and methods for cooling an electric aircraft. Background Art

[0002] Electric aircraft rely on electric motors to generate lift and / or thrust. Electric aircraft also use a variety of other electronic devices to control the electric motors as well as other aircraft functions. These electronic devices may be packaged within the housing. These electronic devices can generate a significant amount of heat, which requires cooling to keep the electronics within their optimal operating temperature range. Conventional cooling systems may involve the use of cooling fins or the housing itself, as well as other types of cooling devices. Conventional cooling systems may result in poor heat spreading capabilities around the surfaces of the electronic device packaging, resulting in reduced cooling effectiveness and decreased electronic functionality. Summary of the invention

[0003] Electronic devices generate heat during operation. As electronic devices operate under more demanding conditions, they generate more and more heat. To operate efficiently, electronic devices should be kept within an ideal operating temperature range. Therefore, electronic devices should be actively or passively cooled. Often, electronic devices are surrounded by protective casings that can help prevent damage to the electronic devices, but this can also further accumulate the heat generated by the electronic devices. The casing can utilize a cooling system to try to cool the electronic devices.

[0004] Conventional cooling systems may involve providing cooling fins on the outside of the housing or on the housing itself to diffuse the heat. These fins or housings are typically arranged in an airflow, and the large surface area of ​​the fins or housing allows the heat to dissipate. However, conventional cooling systems may result in poor heat diffusion along the fins or housing, where most of the heat stays in the portion of the fins or housing that is close to the heat source. This results in inefficient use of the fins and housing due to the failure to use the full surface area of ​​the fins and housing for cooling. This effect is particularly evident in electric aircraft, because the electric motors that provide lift or thrust generate a lot of heat due to the high power requirements of the electronics of the inverter circuits required to drive the electric aircraft. The electric aircraft may be, for example, an electric vertical take-off and landing vehicle (eVTOL). Therefore, a cooling system with higher cooling capacity in the same space is needed to meet the cooling needs of electric aircraft.

[0005] Embodiments of the present disclosure provide a more efficient cooling system than conventional fins by combining the use of a pulsating heat pipe (PHP) with cooling fins and / or housings. The PHP may also be referred to as an oscillating heat pipe (OHP). The PHP includes a channel having an evaporator portion and a condenser portion. A refrigerant is arranged in the channel. The refrigerant can move between the evaporator portion and the condenser portion, transitioning between a gas phase and a liquid phase. This transition can absorb and release heat, thereby absorbing heat from the electronic device and releasing the heat into the airflow at the end of the fin away from the housing. This can provide higher heat transfer capabilities, high heat flux density diffusion capabilities, the ability to withstand the gravitational acceleration experienced by aircraft, performance that is insensitive to orientation, and the advantages of simple structure.

[0006] Embodiments generally include a housing, wherein the housing includes a housing cavity, at least one electronic device, at least one cooling fin connected to the housing, and at least one PHP embedded in at least one of the housing cavity or the cooling fin. The portion of the PHP close to the electronic device generating heat can serve as an evaporator portion of the PHP. The portion of the PHP away from the electronic device generating heat can serve as a condenser portion of the PHP. In some embodiments, the system includes a housing having a plurality of slots and at least one cooling fin segment, wherein the at least one fin segment includes a U-shaped cross-section, and the fin segment can be inserted into the plurality of slots of the housing. In another embodiment, the system is used for eVTOL.

[0007] In one embodiment, a motor assembly includes a motor housing having an end surface, a motor in the motor housing, an electronic assembly arranged on the end surface of the motor housing, wherein the electronic assembly includes a housing having an inner cavity and an outer surface, at least one electronic device arranged in the inner cavity, wherein the housing has at least one fin protruding from the outer surface of the housing, and the fin has a fin inner cavity, and one or more pulsating heat pipes arranged in the inner cavity of the housing, in the inner cavity of the fin, or in both the inner cavity of the housing and the fin cavities of the one or more fins.

[0008] In another embodiment, a motor assembly includes a motor housing having an end surface, a motor in the motor housing, and an electronic assembly arranged on the end surface of the motor housing, wherein the electronic assembly includes a shell having an inner cavity, at least one electronic device arranged in the inner cavity, and the outer surface of the shell includes a plurality of grooves, one or more fin segments include a first fin, a second fin, and a connecting portion connecting the first fin and the second fin, wherein the first fin and the second fin are inserted into the plurality of grooves so that the first fin and the second fin protrude from the outer surface of the shell, wherein the first fin and the second fin each include a fin inner cavity, and one or more pulsating heat pipes arranged in the fin inner cavities of the first fin and the second fin.

[0009] In another embodiment, an electric vertical take-off and landing vehicle (eVTOL) includes a motor assembly, which includes a motor housing having an end surface, a motor in the motor housing, an electronic assembly arranged on the end surface of the motor housing, wherein the electronic assembly includes a housing having an inner cavity and an outer surface, at least one electronic device arranged in the inner cavity, wherein the housing has at least one fin protruding from the outer surface of the housing, and the fin has a fin cavity, and one or more pulsating heat pipes, which are arranged in the housing cavity, in the fin cavity, or in both the housing cavity and the fin cavity of the one or more fins.

[0010] Additional features and advantages of the techniques described in the present disclosure will be set forth in the detailed description that follows, and in part will be apparent to those skilled in the art or may be learned by practicing the techniques described in the present disclosure, including the detailed description that follows, the claims, and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The following detailed description of the present disclosure may be better understood when read in conjunction with the following drawings:

[0012] Figure 1 schematically illustrates a front cross-sectional view of an electric motor, housing, plurality of fins, and propeller assembly according to one or more embodiments shown and described herein;

[0013] Figure 2 schematically illustrates a top view of an electric motor, housing, and fin assembly according to one or more embodiments shown and described herein;

[0014] Figure 3 schematically illustrates a PHP disposed within a cooling fin according to one or more embodiments shown and described herein;

[0015] Figure 4 schematically illustrates a PHP disposed within a housing cavity according to one or more embodiments shown and described herein;

[0016] Figure 5 schematically illustrates a top view of an electric motor, housing, and fin segment assembly according to one or more embodiments shown and described herein;

[0017] Figure 6 schematically illustrates a housing including a plurality of slots according to one or more embodiments shown and described herein;

[0018] Fig. 7A schematically illustrates fin segments insertable into the plurality of slots of a housing according to one or more embodiments shown and described herein;

[0019] Figure 7Bschematically illustrates fin segments inserted into two of the plurality of slots of a housing according to one or more embodiments shown and described herein;

[0020] Figure 8 schematically illustrates an eVTOL having a cooling system according to one or more embodiments shown and described herein;

[0021] Reference will now be made in more detail to various embodiments of the present disclosure, some of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. DETAILED DESCRIPTION

[0022] Embodiments of the present disclosure relate to cooling systems using PHP for electric motors and vehicles such as eVTOL. In an embodiment, the PHP is embedded within the width of a housing cavity or a cooling fin attached to the housing to increase the heat spreading efficiency of the housing or cooling fin. The portion of the PHP closest to the heat source acts as an evaporator. The portion of the PHP farthest from the heat source and placed in the electric aircraft airflow acts as a condensing portion. This arrangement allows for a more even spreading of heat throughout the housing or fins, allowing for greater cooling capacity to remove heat from the electronic equipment.

[0023] The PHP has a complete loop so that the internal contents can pass from the evaporator section to the condenser section, back to the evaporator section, and so on. In some embodiments, the PHP can be arranged in a serpentine manner so that a single PHP can include multiple condenser sections and multiple evaporator sections, all within a single PHP. In some embodiments, the multiple condenser sections and the multiple evaporator sections can all be embedded within a single cooling fin.

[0024] In some embodiments, a single PHP can be disposed within the housing lumen. In some embodiments, a plurality of PHPs can be disposed within the housing lumen.

[0025] In some embodiments, the housing may have multiple cooling fins arranged around it. In some embodiments, a single PHP may be arranged such that the single PHP is embedded within multiple cooling fins. In some embodiments, there may be multiple PHPs such that each of the multiple cooling fins has a single PHP embedded within each cooling fin.

[0026] In some embodiments, multiple slots can be arranged around the housing. One or more fin segments can be shaped to have a U-shaped top view so that a single fin segment fits into two slots. In this arrangement, a single PHP can be embedded in each U-shaped fin segment.

[0027] The term "evaporator" refers to the portion of the PHP where the liquid is converted from a liquid state to a gaseous state and absorbs heat. The term "condenser" refers to the portion of the PHP where the gas is converted from a gaseous state to a liquid state and releases heat.

[0028] Conventional cooling systems may limit heat dissipation and concentrate heat in the portion of the housing or fins closest to the heat source. This does not efficiently utilize the full area of ​​the housing or fins because the heat is not spread across the entire housing or fins, and also reduces the amount of heat removed from the heat source that the housing or fins are designed to cool. Compared to conventional cooling systems, embodiments of the present disclosure may more efficiently transfer heat to the entire housing or fins to more efficiently utilize the total area of ​​the housing or fins and increase the diffusion of heat throughout the housing or fins. This embodiment may also dissipate more heat away from the heat source than conventional cooling systems.

[0029] Reference now Figure 1 , an example system 100 is shown. The system 100 includes a housing 110, a motor 101, one or more electronic devices 113, a propeller 102, and a propeller shaft 103. The electronic device 113 is arranged in a housing cavity 111 (i.e., an enclosed body defined by the housing 110). A plurality of fins 120 are attached to an outer surface 118 of the housing. The propeller shaft 103 is connected to the motor 101 and the propeller 102. The housing 110 may have a through hole 117 to allow the propeller shaft 103 to pass from the motor 101 to the propeller 102. The propeller 102 may provide lift, thrust, or a combination of lift and thrust. Note that although six fins 120 are shown in this embodiment, the system 100 may include any number of fins 120. It should be understood that Figure 1 The arrangement of system components is for illustration purposes, and other arrangements are possible.

[0030] The electronic device 113 in the housing cavity 111 may be one or more different electronic devices 113. The electronic device 113 may be included in an inverter circuit, a gate driver, and / or similar devices. The electronic device 113 may include a capacitor, an insulated gate bipolar transistor, a power MOSFET, or any other electronic device. The electronic device 113 may be a heat source for the system 100, wherein the electronic device 113 generates heat during operation.

[0031] The housing 110 surrounding the electronic device 113 can have a variety of shapes, including but not limited to a cylinder, a ring, or a rectangular prism. The housing 110 can be made of a variety of materials, including but not limited to aluminum. The housing 110 includes at least one wall and an inner cavity. In some embodiments, there may be multiple housings 110 arranged together, each housing 110 having at least one fin 120 attached thereto.

[0032] The system may include a fin 120. The system may include a plurality of fins 120. The fin 120 may be mounted on the housing 110. The fin 120 may be mounted on the housing 110 by various methods, including but not limited to soldering, brazing, and welding. In some embodiments, the fin 120 and the housing 110 may be made of a single piece of material. The fin 120 may have a variety of shapes, including but not limited to a cylinder or a rectangular prism.

[0033] Reference now Figure 2 , a top view of an embodiment of system 100 is shown. A plurality of fins 120 are shown protruding from housing outer surface 118. Through holes 117 are shown. Housing inner surface 115 is also shown. Electronic devices 113 are shown arranged around housing perimeter 114 proximate to housing inner surface 115. Cut line plane AA is shown.

[0034] Reference now Figure 3 , a cross-sectional top view of an embodiment of a system 100 including a PHP 130 embedded in a fin 120 is shown. An electronic device 113 is located in a housing cavity 111. The fin 120 includes a fin cavity 121. The PHP 130 is located in the fin cavity 121. The PHP 130 includes a channel in which alternating refrigerant vapor plugs and liquid plugs are provided. Any known or yet to be developed refrigerant can be used. As a non-limiting example, R404A can be used as a refrigerant. In some embodiments, the PHP 130 includes a single circuit for refrigerant within a single fin 120, so that the portion of the PHP 130 closest to the heat source can be used as a PHP evaporator portion 131, and the portion of the PHP 130 farthest from the heat source can be used as a PHP condenser portion 132. In another embodiment not shown, the PHP 130 includes multiple circuits for refrigerant within the fins 120 such that the PHP 130 includes a single closed loop with multiple PHP evaporator sections 131 closest to the heat source and multiple PHP condenser sections 132 farthest from the heat source within a single PHP 130 .

[0035] Reference now Figure 4 , showing along Figure 2 In some embodiments, the PHP 130 includes a single circuit for the refrigerant in the shell cavity 111, so that the portion of the PHP 130 closest to the heat source can be used as the PHP evaporator portion 131, and the portion of the PHP 130 farthest from the heat source can be used as the PHP condenser portion 132. In another embodiment, the PHP 130 includes multiple circuits for the refrigerant in the shell cavity 111, so that the PHP 130 includes a single closed loop, wherein there are multiple PHP evaporator portions 131 closest to the heat source and multiple PHP condenser portions 132 farthest from the heat source in a single PHP 130.

[0036] While in some embodiments, the fins 120 can be attached to the housing 110 by attaching to the housing outer surface 118, it should be understood that in other embodiments, the fins 120 can be attached to the housing 110 by other means. In other embodiments, the fin segments 225 can be attached to the housing 210 through a plurality of slots in the housing 210.

[0037] Reference now Figure 5 , a top view of another embodiment of the system 100 is shown. A plurality of fin segments 225 are shown inserted through a plurality of slots 216 in the housing 210. The plurality of slots 216 may be arranged axially about the housing 210. A through hole 217 is shown. The housing inner surface 215 is also shown. An electronic device 213 is shown arranged about the housing perimeter 214 proximate to the housing inner surface 215. Cut line plane BB is shown.

[0038] Reference now Figure 6 , shows a cross-sectional front view of an embodiment of a housing 210 having a plurality of slots 216 cut along cutting plane line BB. The slots 216 can be arranged around the housing 210 in any arrangement. The slots 216 can have a variety of shapes, including but not limited to rectangular or circular. The slots can be arranged in pairs.

[0039] Reference now Fig. 7A and 7B , another embodiment of the fins 220A, 220B and the housing 210 is shown. In this embodiment, two fins 220A, 220B are provided by a single fin segment 225. The fin segment 225 is U-shaped and has three parts, wherein the first part defines the first fin 220A and the second part defines the second fin 220B parallel to the first fin 220A. The fin segment 225 also includes a third part, which defines a connecting portion 224 connecting the first fin 220A and the second fin 220B.

[0040] Figure 7B The fins 220A, 220B are shown inserted into the slots 216 of the housing 210. Each fin 220A, 220B protrudes from the housing 210. The connecting portion 224 can be pressed against the inner surface of the housing 210 and further contact one or more electronic devices. The fin segments 225 can be mechanically engaged with the housing 210 by fasteners (not shown), soldering, brazing, adhesives, or any bonding technique.

[0041] As described above, each fin segment 225 includes a single housed PHP 230. In such an embodiment, the condenser portion of the PHP 130 resides in the fins 220A, 220B, and the evaporator portion of the PHP 230 resides in the connection portion 224. The electronic device heats the PHP 230 at the connection portion 224, while the air passing through the fins 220A, 220B cools the PHP 230.

[0042] The plurality of fin segments 225 may be arranged around the entire perimeter of the housing 210 or a portion thereof. The system may include a plurality of PHPs 230 equal to the number of fins 220. This may allow the user to select the exact number of fin segments 225 and PHPs 230 to suit any situation. For example, when the system 200 is operated in an environment with a high ambient temperature, additional fin segments 225 may be provided. In an environment with a lower ambient temperature, fewer fin segments 225 may be provided.

[0043] See now Figure 8 , the system 100 is shown on an eVTOL 140. A plurality of electric motors 101 may be used, which are coupled to a plurality of propellers 102 by a plurality of propeller shafts 103. The eVTOL 140 may take off and land vertically using the lift from the plurality of propellers 102. The plurality of propellers 102 may also provide thrust so that the eVTOL 140 may move forward. The airflow from the propellers 102 may also provide airflow for the fins 120 of the system 100. In another embodiment, the airflow from the propellers 102 may also provide airflow for the fin segments 225. The airflow may cause the PHP condenser portion 132 to condense the refrigerant within each PHP 130, thereby cooling the electronic equipment 113.

[0044] The system 100 can enhance cooling of the electronic devices 113 in electric aircraft, including the eVTOL 140. The system 100 can include a PHP embedded in one or more fins 120. The system 100 can also achieve the desired cooling capacity of the system 100 by the user selecting the desired number of fin segments 225. The fins 120 and fin segments 225 can be arranged in the airflow of the plurality of propellers 102, so that the airflow further cools the PHP condenser portion 132 embedded in the fins 120 or fin segments 225. The PHP 130 can allow for more efficient heat transfer across the fins 120 or across the fin segments 225. This more efficient heat transfer can remove more heat from the electronic devices 113, thereby allowing the electronic devices 113 to operate more efficiently.

[0045] It should be noted that one or more of the following claims use the terms "herein," "wherein," or "wherein" as transitional phrases. For the purpose of defining the present technology, it should be noted that these terms are introduced in the claims as open transitional phrases that are used to introduce a description of a series of structural features and should be interpreted like the more commonly used open introductory term "comprising."

[0046] It should be understood that any two quantitative values ​​assigned to a property may form a range for that property, and that all range combinations formed by all stated quantitative values ​​for a given property are contemplated in the present disclosure.

[0047] Having described the subject matter of the present disclosure in detail and with reference to specific embodiments, it should be noted that the various details described in the present disclosure should not be considered to be related to the essential components of the various embodiments described in the present disclosure, even though specific elements may be shown in each of the accompanying drawings. Instead, the appended claims should be considered as the only representation of the scope of the present disclosure and the corresponding scope of the various embodiments described in the present disclosure. It is further apparent that modifications and variations may be made without departing from the scope of the appended claims.

Claims

1. A motor assembly, comprising: a motor housing having an end surface; an electric motor located within a motor housing; An electronic component is arranged on an end face of a motor housing, and the electronic component comprises: a housing including a housing interior cavity and an exterior surface, wherein the housing defines an enclosure; at least one electronic device located within the enclosure; one or more fins protruding from an outer surface of the housing, wherein the one or more fins include a fin cavity; and One or more pulsating heat pipes are disposed within at least one of: (1) the housing cavity; (2) the fin cavity; and (3) the housing cavity and the fin cavity of the one or more fins. 2 . The electric motor assembly of claim 1 , wherein the housing cavity is coupled to fin cavities of the one or more fins, and the one or more pulsating heat pipes are arranged within the housing cavity and the fin cavities of the one or more fins. 3 . The electric motor assembly according to claim 1 , wherein the housing inner cavity is an evaporator for the one or more pulsating heat pipes, and the fin inner cavity is a condenser for the one or more pulsating heat pipes.

4. The motor assembly of claim 1, wherein the portion of the fin cavity closest to the housing is the evaporator, and the portion of the fin cavity farthest from the housing is the condenser.

5. The motor assembly of claim 1, wherein the at least one electronic device comprises a plurality of electronic devices positioned along a perimeter defined by an inner surface of the housing.

6. The motor assembly of claim 5, wherein the at least one electronic device contacts an inner surface of the housing.

7. The motor assembly of claim 1, further comprising: a propeller shaft coupled to the electric motor and extending through the opening in the housing; as well as A propeller is coupled to the propeller shaft, wherein rotation of the propeller causes air to pass over the one or more fins.

8. The electric motor assembly of claim 1, wherein the pulsating heat pipe has multiple condenser sections and multiple evaporator sections within a single fin.

9. A motor assembly comprising: a motor housing having an end surface; an electric motor located within a motor housing; An electronic component is arranged on an end face of a motor housing, and the electronic component comprises: a housing comprising a housing interior cavity and an exterior surface, wherein the exterior surface comprises a plurality of grooves and the housing defines an enclosure; at least one electronic device located within the enclosure; one or more fin segments including a first fin, a second fin, and a connecting portion connecting the first fin to the second fin, wherein the first fin and the second fin are inserted into the plurality of slots such that the first fin and the second fin protrude from an outer surface of the housing, wherein the first fin and the second fin mocochet include a fin cavity; and One or more pulsating heat pipes are arranged in the fin cavities of the first fin and the second fin. 10 . The motor assembly of claim 9 , wherein the connection portion of the one or more fin segments is an evaporator portion of a pulsating heat pipe, and the fin cavities of the first fin and the second fin are a condenser portion of the pulsating heat pipe.

11. The electric motor assembly of claim 9, wherein the at least one electronic device comprises a plurality of electronic devices arranged along a perimeter defined by an inner surface of the housing, and the one or more fin segments comprises a plurality of fin segments.

12. The electric motor assembly of claim 11, wherein the at least one electronic device contacts a connection portion of the plurality of fin segments.

13. The motor assembly of claim 9, further comprising: a propeller shaft coupled to the electric motor and extending through the opening in the housing; as well as A propeller is coupled to the propeller shaft, wherein rotation of the propeller causes air to pass over the first fin and the second fin of the one or more fin segments.

14. The electric motor assembly of claim 9, wherein the pulsating heat pipe has multiple condenser sections and multiple evaporator sections within a single fin.

15. An electric vertical take-off and landing vehicle (eVTOL), comprising: An electric motor assembly comprising: a motor housing having an end surface; an electric motor located within a motor housing; An electronic component is arranged on an end face of a motor housing, and the electronic component comprises: a housing including a housing interior cavity and an exterior surface, wherein the housing defines an enclosure; at least one electronic device located within the enclosure; one or more fins protruding from an outer surface of the housing, wherein the one or more fins include a fin cavity; and One or more pulsating heat pipes are disposed within at least one of: (1) the housing cavity; (2) the fin cavity; and (3) the housing cavity and the fin cavity of the one or more fins. 16 . The eVTOL of claim 15 , wherein the housing cavity is coupled to fin cavities of the one or more fins, and the one or more pulsating heat pipes are disposed within the housing cavity and the fin cavities of the one or more fins.

17. The eVTOL of claim 15, wherein the housing interior cavity is an evaporator for the one or more pulsating heat pipes, and the fin interior cavity is a condenser for the one or more pulsating heat pipes.

18. The eVTOL of claim 15, wherein the portion of the fin cavity closest to the housing is the evaporator, and the portion of the fin cavity farthest from the housing is the condenser.

19. The eVTOL of claim 15, wherein the at least one electronic device comprises a plurality of electronic devices arranged along a perimeter defined by an inner surface of the housing.

20. The eVTOL of claim 15, further comprising: a propeller shaft coupled to the electric motor and extending through the opening in the housing; as well as A propeller is coupled to the propeller shaft, wherein rotation of the propeller causes air to pass over the one or more fins.

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