A flexible, customized 3D heat pipe, its fabrication method, and its application.

Abstract

This application discloses a flexible, customized 3D heat pipe, its fabrication method, and its application. A portion of the customized 3D heat pipe contacts a control chip to absorb the heat generated by the chip. The remaining portion of the customized 3D heat pipe can be laid along any three-dimensional path of the electronic device as needed. The heat accumulated by the control chip is then transferred to any spatial region within the electronic device where the customized 3D heat pipe is laid. This maximizes the heat dissipation area of ​​the heat pipe without affecting the size of the electronic device or the installation space of other components. Compared to traditional 2D flat heat pipes, this enables more efficient thermal management of the electronic device.

Description

Technical Field

[0001] This application belongs to the field of two-phase cycle thermal management device technology, specifically relating to a flexible, customized 3D heat pipe, its fabrication method, and its application. Background Technology

[0002] Most emerging electronic devices are characterized by their small size, high integration, and irregular shape, making it difficult to directly apply most thermal management solutions due to space constraints. Heat pipe technology, with its advantages of small footprint, high heat transfer efficiency, and low application cost, has become the mainstream heat dissipation solution for addressing the high heat flux density of small electronic devices.

[0003] However, the high-sealing requirements of heat pipes, coupled with their complex and customized forms, pose significant challenges to their sealing processes. This limits the majority of micro heat pipes to simple one- or two-dimensional geometric shapes. While they have achieved significant applications in tablet devices such as smartphones and laptops, in more complex electronic devices like AR / VR glasses and cameras, heat management is limited to the plane containing the electronic components, leaving a vast untapped space for heat distribution.

[0004] Additive manufacturing technology is one of the effective solutions to the customization challenge. Most research focuses on using the characteristics of additive manufacturing to create wick structures with controllable capillary properties, while limited research has directly molded complete structures including the shell and wick. The characteristics of heat pipe devices require manufacturing processes that can meet the requirements of strong sealing, high thermal conductivity, low cost, and lightweight. However, under the current technological limitations of SLM (Surface Mount Technology), SLM technology can only manufacture a thermal management device whose cost and weight exceed those of the electronic device itself, which is unacceptable. Summary of the Invention

[0005] The purpose of this application is to provide a flexible, customized 3D heat pipe, its preparation method, and its application. The customized 3D heat pipe can be laid along any three-dimensional path of an electronic device as needed, making full use of the space of the electronic device for thermal management.

[0006] The technical solution of this application is as follows:

[0007] A flexible, customized 3D heat pipe, installed in an electronic device and partially in contact with the control chip of the electronic device, includes a flexible shell, a flexible wick, and a working fluid;

[0008] A working fluid flow channel is formed inside the flexible shell, and a flexible liquid suction core is set inside the working fluid flow channel. On any cross section of the working fluid flow channel perpendicular to its extension direction, the flexible liquid suction core contacts the top and bottom surfaces of the working fluid flow channel respectively.

[0009] The working fluid flows in the working fluid flow channel. The flexible liquid wick absorbs the liquid working fluid through capillary action. The liquid working fluid absorbs the heat emitted by the control chip and evaporates into a gaseous state. Then, it dissipates heat through the top and bottom surfaces of the working fluid flow channel, condenses into a liquid state, and flows back to the flexible liquid wick.

[0010] In some possible implementations, the cross-section of the flexible absorbent core perpendicular to its extension direction is a curve of a periodic function, which can be a trigonometric function, a polynomial function, or a Gaussian function.

[0011] In some possible implementations, the wavelength of the periodic function is 0.1–2.5 mm, and the amplitude of the periodic function is 0.05–0.75 mm.

[0012] The width of the working fluid flow channel is 5–40 mm, and the height is 0.1–1.5 mm.

[0013] In some possible implementations, the flexible absorbent core is made of hydrophilically treated copper wire mesh, stainless steel wire mesh, or iron-chromium-aluminum wire mesh.

[0014] The flexible shell is composed of two polymer layers and a metal layer disposed between the two polymer layers. The metal layer is made of copper, aluminum or stainless steel, and the polymer layer is made of low-density polyethylene terephthalate, polypropylene or polyethylene.

[0015] In some possible implementations, the flexible absorbent core is obtained by pressing together multiple layers of hydrophilically treated copper wire mesh, stainless steel wire mesh, or iron-chromium-aluminum wire mesh.

[0016] Hydrophilic treatment methods include coating, anodizing, or chemical deposition.

[0017] This application does not limit the working fluid used in the customized 3D heat pipe; any working fluid commonly used by those skilled in the art that does not react with the flexible wick and flexible shell can be selected. For example, the working fluid can be selected from at least one of deionized water, ethanol, and methanol.

[0018] A method for fabricating a customized 3D heat pipe, as described above, includes the following steps:

[0019] (1) Convert the target model into point cloud data, and then plan the shape trajectory of the customized 3D heat pipe along the two-phase circulation direction of the customized 3D heat pipe based on the point cloud data.

[0020] The flexible shell is formed by sealing an upper shell and a lower shell together. The upper shell and the lower shell together form two ports. The upper shell and the lower shell are respectively provided with sealing edges that can be heat-fused and sealed at corresponding positions on their outer edges except for the ports.

[0021] The morphological trajectory includes the sealing edge and the area of ​​abrupt curvature change in the customized 3D heat pipe;

[0022] (2) Extract the coordinates of three-dimensional points in the morphological trajectory, generate three-dimensional surfaces from three-dimensional sheets along the adjacent morphological trajectories in the three-dimensional modeling software, and transform the three-dimensional surfaces into two-dimensional unfolded planes through a two-dimensional mapping algorithm. Then, prepare the upper shell sheet, the lower shell sheet, the liquid-absorbing chip sheet, and the flexible heater with the same shape as the sealing edge along the two-dimensional unfolded plane.

[0023] (3) Combine three-dimensional curved surfaces and morphological trajectories to generate a three-dimensional model of the plastic mold of the flexible liquid-absorbing core and a three-dimensional model of the pre-encapsulated mold of the customized 3D heat pipe. Then, print the plastic mold and the pre-encapsulated mold using photopolymerization 3D printing technology.

[0024] The molding mold includes an upper molding mold and a lower molding mold, and the middle part of the mating surface of the upper molding mold and the lower molding mold has the same shape as the flexible liquid-absorbing core.

[0025] The pre-packaged mold includes an upper pre-packaged mold and a lower pre-packaged mold. The middle part of the mating surface of the upper pre-packaged mold and the lower pre-packaged mold has the same shape as the customized 3D heat pipe.

[0026] (4) Stack multiple absorbent chip materials and place them between the upper and lower molding molds. The upper and lower molding molds apply a normal force to the absorbent chip materials to obtain a three-dimensional absorbent core. The three-dimensional absorbent core is then hydrophilically treated to obtain a flexible absorbent core.

[0027] (5) Stack the pre-packaged upper mold, flexible heater, upper shell sheet, flexible liquid absorber, lower shell sheet and pre-packaged lower mold in sequence. The cooperation of the pre-packaged upper mold and the pre-packaged lower mold applies a normal force to the upper shell sheet and the lower shell sheet. Heat the flexible heater to seal the sealing edge to obtain a pre-packaged heat pipe. The outer edge of the pre-packaged heat pipe that is not sealed by the sealing edge forms two ports.

[0028] (6) Drain one of the ports and then seal the other port. Vacuum and fill the pre-encapsulated heat pipe with working fluid from the port that has been drained. Finally, seal the port that has been drained to obtain a customized 3D heat pipe.

[0029] In the above steps, step (1) is performed using 3D data processing software; in step (2), the generation of the 3D sheet body along the 3D point coordinates is achieved using 3D modeling software; and in step (3), the generation of the 3D model is achieved using computer-aided design software. This application does not limit the software and algorithms used in the preparation method, as long as they can achieve the corresponding functions. For example, the 3D data processing software can be MeshLab, CloudCompare, Autodesk Recap, or Blender; the 3D modeling software can be Matlab, Autodesk 3ds Max, or Rhinoceros; the 2D mapping algorithm can be the minimum energy expansion method, the conformal mapping method, or the isometric mapping method; and the computer-aided design software can be Solidworks, UG, or Catia.

[0030] Among the possible implementations, photopolymerization 3D printing technologies include stereolithography (SLA), digital light processing (DLP), continuous liquid interface production (CLIP), or mask stereolithography (MSLA).

[0031] In some possible implementations, the materials for the molding die and the pre-encapsulation die are independently selected from epoxy resin, phenolic resin, or ceramic resin.

[0032] In some possible implementations, the operation of applying a normal force to the liquid-absorbing chip material by the fit of the upper and lower molding molds is as follows: the upper and lower molding molds are locked together with bolts and nuts, and then left to stand for 30 seconds to 30 minutes.

[0033] The operation of applying normal force to the upper and lower shell sheets by fitting the pre-encapsulation upper mold and the pre-encapsulation lower mold together is as follows: use bolts and nuts to lock the pre-encapsulation upper mold and the pre-encapsulation lower mold together, and then let it stand for 30 seconds to 30 minutes.

[0034] In some possible implementations, the specific operation of the drain port treatment is to install a copper pipe at the port by hot pressing.

[0035] In some possible implementations, the shape trajectory is set along the contour of the electronic device.

[0036] In some possible implementations, the method of preparing the upper shell sheet, lower shell sheet, liquid-absorbing chip sheet, and flexible heater with the same shape as the sealing edge along the two-dimensional unfolded plane is to obtain them by a planar cutting process, which can be laser cutting, die cutting, or knife cutting.

[0037] In some possible implementations, the flexible heater is elongated and can be either a carbon cloth heater or a polyimide heater.

[0038] An electronic device includes the aforementioned customized 3D heat pipe and dissipates heat through the customized 3D heat pipe.

[0039] The customized 3D heat pipe provided in this application can be used to dissipate heat from any electronic device, and is especially suitable for some emerging electronic devices with complex configurations, such as VR headsets, AR glasses, cameras and drones.

[0040] This application has at least the following beneficial effects:

[0041] 1. The customized 3D heat pipe portion of this application contacts the control chip to absorb the heat generated by the control chip. The remaining portion of the customized 3D heat pipe can be laid along any three-dimensional path of the electronic device as needed, and then the heat accumulated by the control chip is transferred to any spatial area of ​​the electronic device where the customized 3D heat pipe is laid. Without affecting the size of the electronic device and the installation space of other components, the heat dissipation area of ​​the customized 3D heat pipe is maximized. Compared with the traditional 2D flat heat pipe, it can achieve more efficient spatial thermal management of electronic devices.

[0042] 2. In some possible implementations, the customized 3D heat pipe of this application includes a flexible metal wick and a flexible shell made of a composite of a metal layer and a polymer layer. The wall thickness of traditional metal heat pipes is mostly in the millimeter range to ensure the sealing performance of the heat pipe, resulting in a relatively large overall weight. However, the composite film of this application introduces a polymer layer (made of high-temperature resistant plastic), which significantly reduces the weight of the customized 3D heat pipe, improves the flexibility of the customized 3D heat pipe, and reduces the cost while ensuring the sealing performance. This makes it possible to manufacture customized 3D heat pipes with complex shapes using 3D printing technology.

[0043] 3. The preparation method of this application uses photopolymerization 3D printing technology to print a molding mold and a pre-encapsulation mold, and then uses the molding mold and the pre-encapsulation mold to realize the shaping of the flexible liquid wick and the pre-encapsulation of the customized 3D heat pipe. Compared with the mainstream technical solution of directly using SLM to print heat pipes, it reduces the cost of using 3D printing technology and the cost of materials, while reducing the weight of the customized 3D heat pipe, increasing the degree of design freedom and reducing the cost required for customization. Attached Figure Description

[0044] Figure 1 For VR headsets and customized 3D heat pipes for VR headsets;

[0045] Figure 2 A schematic diagram of the structure of a customized 3D heat pipe with its cross-section perpendicular to its extension direction;

[0046] Figure 3 This is a drawing showing the shaping and assembly of a flexible liquid-absorbing core.

[0047] Figure 4 This is an assembly diagram for fabricating a pre-packaged heat pipe.

[0048] Figure 5 A comparison of the heat dissipation effects of customized 3D heat pipes and traditional heat pipes in VR headsets.

[0049] Reference numerals: 1-Customized 3D heat pipe; 11-Flexible shell; 111-Working fluid flow channel; 12-Flexible liquid suction core; 21-Upper shaping mold; 22-Lower shaping mold; 23-Liquid suction chip material; 31-Pre-packaged upper mold; 32-Pre-packaged lower mold; 33-Flexible heater; 34-Upper shell sheet; 35-Lower shell sheet; 41-Screw hole; 42-Nut; 43-Bolt; 5-VR headset; 51-Body; 52-Fixing strap. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in more detail below with reference to the accompanying drawings and specific embodiments. However, the scope of protection of this invention is not limited to these embodiments. The same reference numerals throughout the text always represent the same elements, and similar reference numerals represent similar elements.

[0051] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", "vertical", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the perspective view in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0052] Figure 4 and Figure 5 The upper molding mold 21, lower molding mold 22, pre-encapsulated upper mold 31, pre-encapsulated lower mold 32, flexible heater 33, upper shell sheet 34, lower shell sheet 35 and flexible liquid-absorbing core 12 are in the shape of long strips and waves. This is only to show that the above components can be designed into any shape as needed rather than to limit the shape of the above components.

[0053] The technical solution of this application will be further illustrated and described below through embodiments.

[0054] Example 1

[0055] This embodiment fabricates a customized 3D heat pipe 1 for a VR headset 5. The VR headset 5 includes a body 51 and a fixing strap 52. A control chip is disposed in the body 51. Figure 1As can be seen, the shape of the customized 3D heat pipe 1 partially matches the body 51, and a large portion of it is identical in shape to the fixing band 52. In actual assembly, part of the customized 3D heat pipe 1 is placed in the body 51 and contacts the control chip, while the remaining part is placed in the fixing band 52 to maximize the space for thermal management.

[0056] like Figure 2 As shown, the flexible, customized 3D heat pipe 1 includes a flexible shell 11, a flexible wick 12, and a working fluid (not shown in the figure). A working fluid flow channel 111 is formed within the flexible shell 11. The flexible wick 12 is disposed within the working fluid flow channel 111. At any cross-section of the working fluid flow channel 111 perpendicular to its extension direction, the flexible wick 12 contacts the top and bottom surfaces of the working fluid flow channel 111, respectively. The working fluid flows within the working fluid flow channel 111. The flexible wick 12 absorbs the liquid working fluid through capillary action. The liquid working fluid absorbs heat emitted by the control chip and evaporates into a gaseous state. Then, it dissipates heat through the top and bottom surfaces of the working fluid flow channel 111, condenses back into a liquid state, and flows back to the flexible wick 12. This arrangement achieves a two-phase circulation of the working fluid in a gas-liquid coplanar manner, resulting in a relatively small thickness for the customized 3D heat pipe 1.

[0057] Specifically, in this embodiment, the cross-section of the flexible absorbent core 12 is a curve of a polynomial function with a period of 1.5 mm and an amplitude of 0.5 mm (the thickness of the flexible absorbent core 12 is twice the amplitude, i.e., 1 mm).

[0058] In this embodiment, the flexible shell 11 is a metal-plastic film material composed of two polymer layers and a metal layer sandwiched between the two polymer layers, wherein the polymer layer is made of polypropylene and the metal layer is made of aluminum; the flexible liquid-absorbing core 12 is a multi-layer self-supporting copper wire mesh that has been hydrophilically treated.

[0059] The method for fabricating the customized 3D heat pipe 1 in this embodiment includes the following steps:

[0060] (1) Import the target 3D model in STL format into the 3D data processing software, convert the target model into point cloud data through the 3D data processing software, and then plan the morphological trajectory of the customized 3D heat pipe 1 along the two-phase circulation direction of the customized 3D heat pipe 1 based on the point cloud data.

[0061] Among them, the flexible shell 11 of the customized 3D heat pipe 1 includes an upper shell and a lower shell (not shown in the figure) that are covered and sealed. After the upper shell and the lower shell are covered, two ports are formed (not shown in the figure). The upper shell and the lower shell are respectively provided with sealing edges that can be heat-fused and sealed at the corresponding positions of the ports on their outer edges.

[0062] The morphological trajectory includes the sealing edge and the region of curvature abrupt change in the custom 3D heat pipe 1.

[0063] In the above steps, the 3D data processing software is CloudCompare.

[0064] (2) Extract the coordinates of three-dimensional points in the morphological trajectory. In 3D modeling software, generate a 3D surface from the 3D sheet along the adjacent morphological trajectory. Use a 2D mapping algorithm to unfold the 3D surface into a 2D unfolded plane. Then, use laser cutting along the 2D unfolded plane to obtain the upper shell sheet 34, the lower shell sheet 35, the liquid-absorbing chip sheet 23, and the flexible heater 33 with the same shape as the sealing edge. In this embodiment, the flexible heater 33 is a carbon cloth heater, which is heated by applying voltage to it.

[0065] In the above steps, the 3D modeling software is Matlab, and the 2D mapping algorithm is the conformal mapping method.

[0066] (3) Combine three-dimensional curved surfaces and morphological trajectories to generate three-dimensional models of the plastic mold of the flexible liquid-absorbing core 12 and the three-dimensional models of the pre-encapsulated mold of the customized 3D heat pipe 1 in computer-aided design software, and then print the plastic mold and the pre-encapsulated mold by photopolymerization 3D printing technology.

[0067] The molding die includes an upper molding die 21 and a lower molding die 22. The middle part of the mating surface of the upper molding die 21 and the lower molding die 22 has the same shape as the flexible liquid-absorbing core 12.

[0068] The pre-packaged mold includes a pre-packaged upper mold 31 and a pre-packaged lower mold 32. The middle part of the mating surface of the pre-packaged upper mold 31 and the pre-packaged lower mold 32 has the same shape as the customized 3D heat pipe 1.

[0069] In the above steps, the computer-aided design software is Solidworks, the photopolymerization 3D printing technology is digital light processing, and the material of the molding mold and the pre-encapsulation mold is phenolic-based high-temperature resistant photosensitive resin.

[0070] (4) After stacking multiple absorbent chip materials 23, place them between the upper molding mold 21 and the lower molding mold 22. The cooperation of the upper molding mold 21 and the lower molding mold 22 applies a normal force to the absorbent chip material 23 to obtain a three-dimensional absorbent core. The three-dimensional absorbent core is then subjected to hydrophilic treatment to obtain a flexible absorbent core 12.

[0071] (5) The pre-packaged upper mold 31, flexible heater 33, upper shell sheet 34, flexible liquid absorber 12, lower shell sheet 35 and pre-packaged lower mold 32 are stacked in sequence. The pre-packaged upper mold 31 and pre-packaged lower mold 32 are engaged to apply a normal force to the upper shell sheet 34 and lower shell sheet 35, and the flexible heater 33 is heated to seal the sealing edge to obtain a pre-packaged heat pipe. The pre-packaged heat pipe forms two ports on the outer edge that is not sealed by the sealing edge.

[0072] (6) Drain one of the ports and then seal the other port. Vacuum and fill the pre-encapsulated heat pipe with working fluid from the port that has been drained. Finally, seal the port that has been drained to obtain the customized 3D heat pipe 1.

[0073] The following is for reference. Figure 3 and Figure 4 Further explanation of steps (4) and (5) is provided.

[0074] First refer to Figure 3 The mating surfaces of the upper molding die 21 and the lower molding die 22 are periodic contour surfaces obtained by scanning a curve of a periodic function along a planned trajectory. The period of this periodic function is 1.5 mm and the amplitude is 0.5 mm. The non-mating surfaces of the upper molding die 21 and the lower molding die 22 are free-form surfaces obtained by scanning a straight line along a planned trajectory. The upper molding die 21 and the lower molding die 22 are respectively provided with mutually mating screw holes 41 on both sides along their extension direction. The upper molding die 21 and the lower molding die 22 can be locked by bolts 43 and nuts 42.

[0075] The absorbent core material 23 is placed between the upper molding die 21 and the lower molding die 22. Then, nuts 42 are passed through the screw holes 41 on the upper molding die 21 and the lower molding die 22 in sequence, and locked by bolts 43 and nuts 42 to apply a normal force to the absorbent core material 23. After standing for 2 minutes, the bolts 43 and nuts 42 are loosened, and the absorbent core material 23 is shaped by the upper molding die 21 and the lower molding die 22 to obtain a three-dimensional absorbent core with a periodic contour surface. The three-dimensional absorbent core is then subjected to hydrophilic treatment to obtain a flexible absorbent core 12.

[0076] like Figure 4 As shown, the mating surfaces of the pre-encapsulation upper mold 31 and the pre-encapsulation lower mold form a curved rectangular groove extending along a planned trajectory in the middle, and the two sides of the pre-encapsulation upper mold 31 and the pre-encapsulation lower mold 32 form contact surfaces that contact each other along the extension direction. The width of the curved rectangular groove is 15mm and the height is 1mm. The non-mating surfaces of the pre-encapsulation upper mold 31 and the pre-encapsulation lower mold are free-form surfaces scanned by a straight line along the planned trajectory. The pre-encapsulation upper mold 31 and the pre-encapsulation lower mold 32 are respectively provided with mutually mating screw holes 41 on the contact surfaces, and the pre-encapsulation upper mold 31 and the pre-encapsulation lower mold 32 can be locked by bolts 43 and nuts 42.

[0077] The width of the upper shell sheet 34 and the lower shell sheet 35 is slightly larger than the width of the curved rectangular groove, so that the parts on both sides of the upper shell sheet 34 that serve as the sealing edges of the upper shell do not enter the curved rectangular groove and do not contact the screw hole 41, and the same applies to the lower shell.

[0078] The pre-encapsulated upper mold 31, flexible heater 33, upper shell sheet 34, flexible liquid-absorbing core 12, lower shell sheet 35, and pre-encapsulated lower mold are stacked sequentially, with the shape and position of the flexible heater 33 corresponding to the sealing edge. Nuts 42 are then passed through the pre-encapsulated upper mold 31 and lower shell sheet 35 sequentially, and tightened by bolts 43 and nuts 42 to apply normal force to the upper shell sheet 34 and lower shell sheet 35. After standing for 15 minutes, the bolts 43 and nuts 42 are loosened, and the upper shell sheet 34 and lower shell sheet 35 are shaped to form the upper and lower shells, respectively. A working fluid flow channel containing the flexible liquid-absorbing core 12 is formed between the upper and lower shells. The flexible heater 33 then heats the upper shell sheet 34 and lower shell sheet 35 to seal the sealing edge, resulting in a pre-encapsulated heat pipe. All sides of the pre-encapsulated heat pipe, except for the two ports, are sealed.

[0079] One port is treated as a drain port, and then the other port is sealed. The pre-encapsulated heat pipe is evacuated and filled with working fluid through the port that has been treated as a drain port. Finally, the port that has been treated as a drain port is sealed, thus obtaining the customized 3D heat pipe 1 of this embodiment.

[0080] Figure 5 The image shows a comparison of the heat dissipation performance of the customized 3D heat pipe 1 with several existing heat pipes in the VR headset 5 device. It can be seen that under the same heating power, the customized 3D heat pipe 1 can reduce the absolute temperature by about 40% to 50% and increase the maximum heating power by 3 to 5 times.

[0081] The above description is merely a preferred embodiment of this application, and therefore cannot be used to limit the scope of this application. All equivalent changes and modifications made in accordance with the patent scope and specification of this application should still fall within the scope of this application.

Claims

1. A method for fabricating a customized 3D heat pipe, characterized in that, A customized 3D heat pipe is installed in an electronic device and partially contacts the control chip of the electronic device. It includes a flexible shell, a flexible liquid-absorbing core, and a working fluid. A working fluid flow channel is formed inside the flexible shell, and the flexible liquid-absorbing core is disposed inside the working fluid flow channel. On any cross-section of the working fluid flow channel perpendicular to its extension direction, the flexible liquid-absorbing core contacts the top surface and bottom surface of the working fluid flow channel respectively. The working fluid flows in the working fluid flow channel. The flexible liquid-absorbing core absorbs the liquid working fluid through capillary action. The liquid working fluid absorbs the heat emitted by the control chip and evaporates into a gaseous state. Then, it dissipates heat through the top and bottom surfaces of the working fluid flow channel, condenses into a liquid state, and flows back to the flexible liquid-absorbing core. Its preparation method includes the following steps: (1) Convert the target model into point cloud data, and then plan the shape trajectory of the customized 3D heat pipe along the two-phase circulation direction of the customized 3D heat pipe based on the point cloud data. The flexible shell is formed by sealing an upper shell and a lower shell together. The upper shell and the lower shell together form two ports. The upper shell and the lower shell are respectively provided with heat-fused sealing edges at corresponding positions on their outer edges, excluding the ports. The morphological trajectory includes the area of ​​abrupt curvature change of the sealing edge and the customized 3D heat pipe; (2) Extract the coordinates of three-dimensional points in the morphological trajectory, generate a three-dimensional surface from the three-dimensional sheet along the adjacent morphological trajectory in the three-dimensional modeling software, and expand the three-dimensional surface into a two-dimensional unfolded plane through a two-dimensional mapping algorithm. Then, prepare the upper shell sheet, the lower shell sheet, the liquid-absorbing chip sheet and the flexible heater with the same shape as the sealing edge along the two-dimensional unfolded plane. (3) Combine the three-dimensional curved surface and the morphological trajectory to generate a three-dimensional model of the molding mold of the flexible liquid-absorbing core and a three-dimensional model of the pre-encapsulation mold of the customized 3D heat pipe, and then print the molding mold and the pre-encapsulation mold by photopolymerization 3D printing technology; The molding die includes an upper molding die and a lower molding die, and the middle part of the mating surface of the upper molding die and the lower molding die has the same shape as the flexible liquid-absorbing core. The pre-packaged mold includes an upper pre-packaged mold and a lower pre-packaged mold, and the middle part of the mating surface of the upper pre-packaged mold and the lower pre-packaged mold is formed with the same shape as the customized 3D heat pipe. (4) After stacking multiple pieces of the liquid-absorbing chip material, place them between the upper molding mold and the lower molding mold. The upper molding mold and the lower molding mold apply a normal force to the liquid-absorbing chip material to obtain a three-dimensional liquid-absorbing core. Perform hydrophilic treatment on the three-dimensional liquid-absorbing core to obtain the flexible liquid-absorbing core. (5) The pre-packaged upper mold, the flexible heater, the upper shell sheet, the flexible liquid-absorbing core, the lower shell sheet and the pre-packaged lower mold are stacked in sequence. The cooperation of the pre-packaged upper mold and the pre-packaged lower mold applies a normal force to the upper shell sheet and the lower shell sheet, and heats the flexible heater to seal the sealing edge to obtain a pre-packaged heat pipe. The pre-packaged heat pipe forms two ports on the outer edge that is not sealed by the sealing edge. (6) Drain one of the ports, then seal the other port, evacuate and fill the pre-encapsulated heat pipe with working fluid from the port that has been drained, and finally seal the port that has been drained to obtain the customized 3D heat pipe.

2. The preparation method according to claim 1, characterized in that, The cross-section of the flexible absorbent core perpendicular to its extension direction is a curve of a periodic function, which is a trigonometric function, a polynomial function, or a Gaussian function.

3. The preparation method according to claim 2, characterized in that, The wavelength of the periodic function is 0.1~2.5mm, and the amplitude of the periodic function is 0.05~0.75mm; The working fluid flow channel has a width of 5~40mm and a height of 0.1~1.5mm.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The flexible liquid-absorbing core is made of hydrophilic copper wire mesh, stainless steel wire mesh, or iron-chromium-aluminum wire mesh. The flexible shell is composed of two polymer layers and a metal layer disposed between the two polymer layers. The metal layer is made of copper, aluminum or stainless steel, and the polymer layer is made of low-density polyethylene terephthalate, polypropylene or polyethylene.

5. The preparation method according to claim 4, characterized in that, The flexible liquid-absorbing core is obtained by pressing together multiple layers of hydrophilic-treated copper wire mesh, stainless steel wire mesh or iron-chromium-aluminum wire mesh. The hydrophilic treatment method is a coating method, anodizing method, or chemical deposition method.

6. The preparation method according to claim 1, characterized in that, The photopolymerization 3D printing technology is stereolithography, digital light processing, continuous liquid interface production, or mask stereolithography. And / or, the materials of the molding die and the pre-encapsulated die are independently selected from epoxy resin, phenolic resin or ceramic resin.

7. The preparation method according to claim 1 or 6, characterized in that, The operation of applying a normal force to the liquid-absorbing chip material by the cooperation of the upper and lower shaping molds is as follows: the upper and lower shaping molds are locked together with bolts and nuts, and then left to stand for 30 seconds to 30 minutes. The operation of applying normal force to the upper and lower shell sheets by the cooperation of the pre-encapsulation upper mold and the pre-encapsulation lower mold is as follows: the pre-encapsulation upper mold and the pre-encapsulation lower mold are locked together with bolts and nuts, and then left to stand for 30 seconds to 30 minutes.

8. The preparation method according to claim 1 or 6, characterized in that, The specific operation for the drain outlet treatment is as follows: a copper pipe is installed at the port by hot pressing.

9. An electronic device, characterized in that, The invention includes a customized 3D heat pipe prepared by the preparation method described in any one of claims 1 to 8, and heat dissipation is performed through the customized 3D heat pipe.

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