Systems and methods for cooling electric aircraft
By introducing a combination of self-excited vibration heat pipe (PHP) and the heat diffusion shell into the cooling system of electric aircraft, the problem of insufficient heat diffusion capacity of traditional cooling systems within space limitations is solved, and more efficient heat dissipation and wider applicability are achieved.
Patent Information
- Application Number
- JP2024184092
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-10-20
- Filing Date
- 2024-10-18
- Publication Date
- 2025-05-02
AI Technical Summary
The cooling systems of existing electric aircraft are difficult to meet the needs of efficient cooling within space limitations, especially when electronic devices generate a large amount of heat. The thermal diffusion capability of traditional cooling systems is insufficient, resulting in the inability of electronic devices to effectively maintain the optimal operating temperature range.
A cooling system is adopted that combines self-excited vibration heat pipe (PHP) with a heat diffusion shell. PHP includes an evaporator and a condenser part, which absorbs and releases heat through the refrigerant changes between different phases to achieve effective diffusion of heat.
It improves heat transfer ability, can effectively dissipate high heat flow, adapts to the mechanical conditions encountered by the aircraft, does not require a specific direction, and is relatively simple in structure, which improves the overall cooling efficiency.
Smart Images
Figure 2025071062000001_ABST
Abstract
Description
[Technical field]
[0001] The present disclosure relates to systems and methods for cooling electric aircraft. [Background technology]
[0002] Electric aircraft rely on motors to generate lift and / or thrust. Electric aircraft also use various other electronic devices to control aircraft functions and complete various tasks. One type of electric aircraft may be an electric vertical take-off and landing (eVTOL). These electronic devices may be packaged together in a casing. These electronic devices may generate significant heat that requires cooling to keep the electronics within their optimal operating temperature range. Traditional cooling systems, among other types of cooling devices, may involve using the faces of the casing to spread the heat. Traditional cooling systems may result in poor heat spreading capability around the packaging faces of the electronics, which may result in less cooling effectiveness and less electronic functionality. Summary of the Invention
[0003] Electronic devices generate heat during operation. Operating electronic devices in more demanding conditions causes the electronic devices to generate even more heat. To operate effectively, electronic devices need to be maintained within an ideal operating temperature range. Thus, electronic devices need to be cooled. Electronic devices are often surrounded by a protective casing, which may help prevent damage to the electronic device, but may also trap heat generated by the electronic device. The casing may utilize a cooling system to attempt to cool the electronic device. A conventional cooling system may involve the use of the surface area of the casing itself to spread heat out. However, a conventional cooling system may result in poor heat spreading along the casing, where most of the heat remains in the portion of the casing closest to the heat source, and little heat spreads to the portion of the casing furthest from the heat source. This results in an inefficient use of the casing surface area, as the entire surface area is not used for cooling. This effect is particularly relevant to electronic aircraft, where the motors providing lift or thrust can generate significant amounts of heat due to the large power draw required to power the electric aircraft. Thus, there is a need for cooling systems that have increased cooling capacity in the same amount of space to accommodate the cooling demands of electronic aircraft.
[0004] The system may be a more efficient cooling system than conventional cooling systems by utilizing a self-excited oscillating heat pipe (PHP) in conjunction with a heat spreading casing. The PHP may also be referred to as an oscillating heat pipe (OHP). The PHP includes a channel having an evaporator section and a condenser section. A refrigerant is disposed within the channel. The refrigerant may change between gas and liquid phases and move between the evaporator section and the condenser section. Such changes may absorb and release heat, resulting in heat being absorbed from the electronic device and released to the airflow at the end of the fin away from the casing. This may provide advantages of higher heat transfer capacity, spreading of high heat flux, ability to withstand g-forces experienced by aircraft, orientation-independent performance, and simplicity of construction.
[0005] In one embodiment, an electric motor assembly includes a motor housing having an end face, a motor within the motor housing, and an electronics assembly disposed on the motor housing end face, the electronics assembly including a casing, the casing including an inner casing wall and an outer casing wall, a space between the inner casing wall and the outer casing wall defining a first casing width, and at least one PHP embedded within the first casing width.
[0006] In another embodiment, an electric motor assembly includes a motor housing having an end face, a motor within the motor housing, and an electronics assembly disposed on the motor housing end face, the electronics assembly including a casing, the casing including a casing inner base, a casing outer base, a space between the casing inner wall and the casing outer wall defining a first casing width, the space between the casing inner wall, the casing outer wall, the casing outer base, and the casing inner base defining a second casing width, the first casing width and the second casing width including a single channel having at least one connection point, and at least one PHP integrated within the single channel.
[0007] In yet another embodiment, an electric vertical take-off and landing (eVTOL) vehicle includes an electric motor assembly including a motor housing having an end face, a motor within the motor housing, and an electronics assembly disposed on the motor housing end face, the electronics assembly including a casing, the casing including an inner casing wall and an outer casing wall, a space between the inner casing wall and the outer casing wall defining a first casing width, and at least one PHP embedded within the first casing width.
[0008] Additional features and advantages of the techniques described in this disclosure will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description, or will be learned by practicing the techniques as described in this disclosure, including the following detailed description, the claims, and the accompanying drawings. [Brief description of the drawings]
[0009] The following detailed description of the disclosure can be better understood when read in conjunction with the following drawings.
[0010] [Figure 1] A figure that diagrammatically depicts a front cross-sectional view of a casing having a first casing width and a second casing width, and a connection point including a single fluid connecting channel with a PHP integrated within the single fluid connecting channel. [Diagram 2] FIG. 2 is a diagram illustrating a front cross-sectional view of a casing having a first casing width and a PHP integrated within the first casing width. [Diagram 3] FIG. 2 is a schematic depiction of a front cross-sectional view of a motor, a casing, a number of fins, and a propeller assembly according to one or more embodiments shown and described herein. [Figure 4] FIG. 1 illustrates a schematic depiction of a system configured for use in an eVTOL.
[0011] Reference will now be made in more detail to various embodiments of the present disclosure, some embodiments of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] An embodiment of the present disclosure utilizes a PHP in an electronics casing to provide cooling to components of an electric machine, such as an eVTOL. More specifically, the system includes one or more PHPs within the width of a casing housing an electronic device to increase the heat spreading efficiency of the casing. The portion of the PHP closest to the heat source acts as an evaporator. The portion of the PHP furthest from the heat source and located within the airflow of the electronic vehicle acts as a condenser. This arrangement allows for more uniform heat spreading throughout the casing and greater cooling capacity to remove heat from the electronic device.
[0013] The PHP is a complete loop such that the internal contents may pass from the evaporator section through the condenser section, back to the evaporator section, etc. In some embodiments, the PHP may be arranged in a serpentine fashion such that a single PHP may contain multiple condenser sections and multiple evaporator sections all within a single PHP, in some embodiments, all incorporated within a single internal channel.
[0014] In some embodiments, the casing condenser section may have one or more cooling fins disposed about the periphery of the casing.
[0015] The term "evaporator" refers to the part of the PHP where a liquid is changed from a liquid to a gas, absorbing heat. The term "condenser" refers to the part of the PHP where a gas is changed from a gas to a liquid, releasing heat.
[0016] Conventional cooling systems may limit heat spread and concentrate heat in the portions of the casing closest to the heat source. This does not efficiently use the full area of the casing as the heat does not dissipate throughout the casing, and also removes less heat from the heat source that the casing is designed to cool compared to conventional cooling systems. Embodiments of the present disclosure may transfer heat more effectively throughout the casing, more efficiently use the full area of the casing, and increase the spread of heat throughout the casing compared to conventional cooling systems. Embodiments may also dissipate more heat from the heat source compared to conventional cooling systems.
[0017] 1, a front cross-sectional view of an embodiment of a system 100 is shown. The system 100 includes a casing 110. The casing 110 includes a casing wall 123. The casing wall 123 includes a casing inner wall 115 and a casing outer wall 112. The casing inner wall 115 and the casing outer wall 112 define a first casing width W1. The casing 110 further includes a casing base 124. The casing base 124 includes a casing inner base 119 and a casing outer base 118. The casing inner base 119 and the casing outer base 118 define a second casing width W2. The first casing width W1 and the second casing width W2 include a single fluid connection channel 122. The single fluid connection channel 122 includes a connection point 121. The connection point 121 can be a corner of the casing 110. The PHP 130 may be incorporated within a single fluid connecting channel 122. The PHP condenser section 132 may be incorporated within a first casing width W1. The PHP evaporator section 131 may be incorporated within a second casing width W2.
[0018] This embodiment may allow the electronic device 113 to be positioned in the casing base 124 such that the electronic device 113 is proximate to the PHP evaporator section 131. The casing wall 123 may be positioned in the airflow of the propeller 102 such that the airflow may be proximate to the PHP condenser section 132. A number of fins 125 may be attached to the casing wall 123.
[0019] In some embodiments, the PHP 130 includes a single circuit for refrigerant inside the single fluid connection channel 122 such that the portion of the PHP 130 integrated within the second casing width W2 can function as a PHP evaporator section 131 and the portion of the PHP integrated within the first casing width W1 can function as a PHP condenser section 132. In other embodiments, the PHP 130 includes multiple circuits for refrigerant inside the casing width such that the PHP 130 includes a single closed loop, and there are multiple PHP evaporator sections 131 integrated within the second casing width W2 and there are multiple PHP condenser sections 132 integrated at the first casing width W1, the multiple circuits comprising a single PHP 130.
[0020] 2, a front view of an embodiment of the system 100 is shown. The system 100 includes a casing 110 having a casing inner wall 115 and a casing outer wall 112. The casing inner wall 115 and the casing outer wall 112 define a first casing width W1. The PHP 130 may be incorporated inside the first casing width W1. The PHP 130 includes channels, with alternating vapor plugs and liquid slugs of refrigerant disposed within the channels. As a non-limiting example, R404A may be used as the refrigerant. In some embodiments, the PHP 130 includes a single circuit for refrigerant inside the first casing width W1, such that a portion of the PHP 130 closest to the heat source may function as a PHP evaporator section 131, and a portion of the PHP furthest from the heat source may function as a PHP condenser section 132. In another embodiment, the PHP 130 includes multiple circuits for the refrigerant inside the casing width W1 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 furthest from the heat source in the single PHP 130. The electronic device 113 may be a heat source for the system 100.
[0021] 3, an exemplary system 100, such as a system for an eVTOL, is shown. The system 100 includes a casing 110, a motor 101, one or more electronic devices 113, a propeller 102, and a propeller shaft 103. The electronic device 113 is disposed within a casing interior cavity 111. A number of fins 125 extend from the exterior of the casing 110. The propeller shaft 103 is connected to the motor 101 and the propeller 102. The casing 110 may have a passage 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. Any number of fins 125 may be provided.
[0022] The electronic device 113 in the casing interior cavity 111 can be one or more different electronic devices 113. The electronic device 113 can be included in an inverter circuit including power electronic devices, gate drive electronic devices, and / or the like. The electronic device 113 can include a capacitor, an insulated gate bipolar transistor, a power MOSFET, or any other electronic device. The electronic device 113 can be a heat source for the system 100, where the electronic device generates heat during operation.
[0023] The casing 110 surrounding the electronic device 113 can be any number of shapes, including but not limited to a cylinder, a toroid, or a rectangular prism. The casing 110 can be made of any number of materials, including but not limited to aluminum. The casing 110 includes at least one wall and an interior cavity (i.e., an enclosure). The casing 110 has a casing wall 123 and a casing base 124. In some embodiments, there can be multiple casings 110 arranged together, with each casing 110 having at least one fin 125 attached thereto.
[0024] The fins 125 may be attached to the casing 110. For example, the fins 125 may be attached to the casing 110 by a variety of methods, including, but not limited to, soldering, brazing, and welding. In some embodiments, the fins 125 and the casing 110 may be made from a single piece of material (e.g., by casting or machining). The fins 125 may be any number of shapes, including, but not limited to, a cylinder or a rectangular prism.
[0025] 4, the system 100 is shown in an eVTOL 140. Multiple motors 101 connected to multiple propellers 102 by multiple propeller shafts 103 may be used. The eVTOL 140 may use lift from the multiple propellers 102 to take off and land vertically. The multiple propellers 102 may also provide thrust so that the eVTOL 140 may move forward. Airflow from the propellers 102 may also provide airflow to the fins 125 (not shown), the casing walls 123 (not shown), or both the fins 125 and the casing walls 123. The airflow may enable the PHP condenser section 132 to condense a refrigerant inside the PHP 130, which may cool the electronic device 113.
[0026] There is a need for a cooling system for an electronic aircraft with improved cooling capacity that can operate in the same amount of space as a conventional cooling system. The cooling system may incorporate a PHP within the width of the casing. The PHP may be incorporated inside both the casing floor and the casing walls to allow for a larger surface area of the casing to be used to increase the cooling capacity of the system. An electronic device may be placed in the casing where the electronic device generates heat. The electronic device may be attached to the casing floor such that the electronic device is in contact with the evaporator section of the PHP. Airflow from the propellers of the electric aircraft may pass over the condenser section of the PHP. This arrangement may use most of the surface area of the casing (both base and walls) to maximize the cooling effect of the system.
[0027] It may be noted that one or more of the following claims utilize the terms "where," "wherein," or "in which" as transitional phrases. For purposes of defining the present technology, it may be noted that these terms are introduced in the claims as open-ended transitional phrases used to introduce a description of a series of features of a structure, and are to be interpreted in a similar manner to the more commonly used open-ended preamble term "comprising."
[0028] It is understood that any two quantitative values assigned to a property may constitute a range for that property, and all combinations of ranges formed from all recited quantitative values for a given property are contemplated in this disclosure.
[0029] Although the subject matter of the present disclosure has been described in detail by referring to certain embodiments, it may be noted that various details described in the present disclosure should not be considered as implying that the details relate to elements that are essential devices of the various embodiments described in the present disclosure, even if a particular element may be shown in each of the drawings accompanying this specification. Rather, the claims attached hereto should be considered as the only expression of the breadth of the present disclosure and the corresponding scope of the various embodiments described in the present disclosure. Moreover, it will be apparent that modifications and variations are possible without departing from the scope of the appended claims.
[0030] Example 1. An electric motor assembly comprising: a motor housing having an end surface; a motor within the motor housing; an electronics assembly disposed on the end surface of the motor housing; the electronics assembly comprising: a casing having a casing interior cavity and a casing outer wall and a casing inner wall, a first casing width being between the casing inner wall and the casing outer wall; at least one electronic device within the casing interior cavity; one or more oscillating heat pipes embedded within the first casing width; An electric motor assembly comprising: Example 2. An electric motor assembly as described in Example 1, wherein the portion of the casing interior cavity in contact with the at least one electronic device is an evaporator and the portion of the casing interior cavity not in contact with the at least one electronic device is a condenser. Example 3. The electric motor assembly of example 1, wherein the at least one electronic device is in contact with the casing inner wall. Example 4. A propeller shaft connected to the motor and passing through an opening in the casing; a propeller connected to the propeller shaft, the rotation of the propeller causing air to pass by the casing outer wall; 2. The electric motor assembly of example 1, further comprising: Example 5. The electric motor assembly of example 1, wherein the self-oscillating heat pipe has a plurality of condenser sections and a plurality of evaporator sections. Example 6. An electric motor assembly comprising: a motor housing having an end surface; a motor within the motor housing; an electronics assembly disposed on the end surface of the motor housing; the electronics assembly comprising: a casing comprising: a casing interior cavity; a casing exterior wall and a casing interior wall, a first casing width being between the casing exterior wall and the casing interior wall; and a casing exterior base and a casing interior base, a second casing width being between the casing exterior base and the casing interior base, wherein the first casing width and the second casing width comprise a single fluid connection channel with at least one connection point; at least one electronic device within the single fluid connection channel; one or more oscillating heat pipes embedded within the single fluid connecting channel; An electric motor assembly comprising: Example 7. The electric motor assembly of example 6, wherein the first casing width is an evaporator section of the self-oscillating heat pipe and the second casing width is a condenser section of the self-oscillating heat pipe. Example 8. The electric motor assembly of example 6, wherein a plurality of electronic devices are in contact with the casing inner wall. Example 9. A propeller shaft connected to the motor and passing through an opening in the casing; a propeller connected to the propeller shaft, the rotation of the propeller causing air to pass by the casing outer wall; 7. The electric motor assembly of example 6, further comprising: Example 10. The electric motor assembly of example 6, wherein the self-oscillating heat pipe has a plurality of condenser sections and a plurality of evaporator sections. Example 11. An electric vertical take-off and landing aircraft (eVTOL) having an electric motor assembly, The electric motor assembly includes: a motor housing having an end surface; a motor within the motor housing; an electronics assembly disposed on the end surface of the motor housing; the electronics assembly comprising: a casing comprising a casing interior cavity, a casing exterior wall, and a casing inner wall, a first casing width being between the casing interior wall and the casing exterior wall, the casing defining an enclosure; at least one electronic device within the enclosure; one or more oscillating heat pipes embedded within the first casing width; Equipped with an eVTOL. Example 12. A housing further comprising a casing outer base and a casing inner base, a second casing width being between the casing outer base and the casing inner base, the first casing width and the second casing width comprising a single fluid connection channel comprising at least one connection point; The eVTOL of Example 11, wherein the one or more oscillating heat pipes are integrated within the single fluid connecting channel. Example 13. The eVTOL of Example 11, wherein the portion of the casing interior cavity in contact with the at least one electronic device is an evaporator and the portion of the casing interior cavity not in contact with the at least one electronic device is a condenser. Example 14. The eVTOL of example 11, wherein a plurality of electronic devices are in contact with the casing inner wall. Example 15. A propeller shaft connected to the motor and passing through an opening in the casing; a propeller connected to the propeller shaft, the rotation of the propeller causing air to pass by the casing outer wall; The eVTOL of Example 11, further comprising: Example 16. The eVTOL of example 11, wherein the self-oscillating heat pipe has a plurality of condenser sections and a plurality of evaporator sections.
Claims
1. 1. An electric motor assembly comprising: a motor housing having an end surface; a motor within the motor housing; an electronics assembly disposed on the end surface of the motor housing; the electronics assembly comprising: a casing having a casing interior cavity and an outer casing wall and an inner casing wall, a first casing width being between the inner casing wall and the outer casing wall; at least one electronic device within the casing interior cavity; one or more oscillating heat pipes embedded within the first casing width; An electric motor assembly comprising:
2. 2. The electric motor assembly of claim 1, wherein a portion of the casing interior cavity in contact with the at least one electronic device is an evaporator and a portion of the casing interior cavity not in contact with the at least one electronic device is a condenser.
3. The electric motor assembly of claim 1 , wherein the at least one electronic device is in contact with the casing inner wall.
4. a propeller shaft connected to the motor and passing through an opening in the casing; a propeller connected to the propeller shaft, the rotation of the propeller causing air to pass by the casing outer wall; The electric motor assembly of claim 1 further comprising:
5. The electric motor assembly of claim 1 , wherein the self-oscillating heat pipe has multiple condenser sections and multiple evaporator sections.
6. 1. An electric motor assembly comprising: a motor housing having an end surface; a motor within the motor housing; an electronics assembly disposed on the end surface of the motor housing; the electronics assembly comprising: a casing comprising: a casing interior cavity; a casing exterior wall and a casing interior wall, a first casing width being between the casing exterior wall and the casing interior wall; and a casing exterior base and a casing interior base, a second casing width being between the casing exterior base and the casing interior base, wherein the first casing width and the second casing width comprise a single fluid connection channel with at least one connection point; at least one electronic device in said single fluid connection channel; one or more oscillating heat pipes embedded within the single fluid connecting channel; An electric motor assembly comprising:
7. 7. The electric motor assembly of claim 6, wherein the first casing width is an evaporator section of the self-oscillating heat pipe and the second casing width is a condenser section of the self-oscillating heat pipe.
8. The electric motor assembly of claim 6 , wherein a plurality of electronic devices are in contact with the casing inner wall.
9. a propeller shaft connected to the motor and passing through an opening in the casing; a propeller connected to the propeller shaft, the rotation of the propeller causing air to pass by the casing outer wall; The electric motor assembly of claim 6 further comprising:
10. The electric motor assembly of claim 6 , wherein the self-oscillating heat pipe has multiple condenser sections and multiple evaporator sections.
11. 1. An electric vertical take-off and landing aircraft (eVTOL) comprising an electric motor assembly, The electric motor assembly includes: a motor housing having an end surface; a motor within the motor housing; an electronics assembly disposed on the end surface of the motor housing; the electronics assembly comprising: a casing comprising a casing interior cavity, a casing exterior wall, and a casing interior wall, a first casing width being between the casing interior wall and the casing exterior wall, the casing defining an enclosure; at least one electronic device within the enclosure; one or more oscillating heat pipes embedded within the first casing width; An eVTOL comprising:
12. a casing outer base and a casing inner base, a second casing width being between the casing outer base and the casing inner base, the first casing width and the second casing width comprising a single fluid connection channel comprising at least one connection point; The eVTOL of claim 11 , wherein the one or more self-oscillating heat pipes are integrated within the single fluid connecting channel.
13. 12. The eVTOL of claim 11, wherein a portion of the casing interior cavity in contact with the at least one electronic device is an evaporator and a portion of the casing interior cavity not in contact with the at least one electronic device is a condenser.
14. a propeller shaft connected to the motor and passing through an opening in the casing; a propeller connected to the propeller shaft, the rotation of the propeller causing air to pass by the casing outer wall; The eVTOL of claim 11 , further comprising:
15. The eVTOL of claim 11 , wherein the self-oscillating heat pipe has multiple condenser sections and multiple evaporator sections.