Polymer heat sink and preparation method thereof

Abstract

The present application provides a polymer heat spreader and a preparation method thereof, wherein the polymer heat spreader comprises: a heat spreader body, comprising a bottom plate, side walls and support columns, the support columns being arranged on the bottom plate, the side walls being arranged around the periphery of the bottom plate, the bottom plate and the side walls enclosing each other to form a receiving groove, the receiving groove being used as a steam channel; a liquid wick for receiving a liquid working medium, the liquid wick being arranged on the bottom plate and located in the receiving groove, the liquid wick being provided with grooves arranged in an array, the groove walls of the grooves being embedded with high thermal rate metal wires, the end face of one end of the high thermal rate metal wires being flush with or protruding from the groove walls of the grooves, the liquid wick being injection molded from a thermoplastic polymer. The polymer heat spreader and the preparation method thereof provided by the present application form a liquid wick with a composite material wall groove structure composed of broken and curled metal wire ends and thermoplastic polymers, which greatly improves the capillary performance, and the heat can be directly introduced into the grooves through the end faces of the metal wires, thereby improving the problem of low thermal conductivity of the polymer material.

Description

Technical Field

[0001] The present application belongs to the technical field of vapor chambers, and more specifically, relates to a polymer vapor chamber and a preparation method thereof. Background Art

[0002] As a two-phase gas-liquid heat dissipation element, the vapor chamber utilizes the two-phase gas-liquid circulation of a working fluid within a closed cavity to rapidly dissipate localized heat, thereby achieving efficient thermal management and significantly improving the safety, reliability, and service life of electronic products. In recent years, electronic products have been developing towards becoming thinner, foldable, and flexible, such as foldable phones and flexible displays. The flexible and ultra-thin heat dissipation issues of these new electronic products urgently need to be addressed.

[0003] Polymer vapor chambers, due to their light weight and flexibility, are considered the most promising heat transfer components for semiconductor electronic devices and microelectronic systems. However, due to drawbacks such as poor thermal conductivity, slow thermal response, and low mechanical strength, existing polymer vapor chambers offer poor heat dissipation and are prone to breakage when deformed, leading to failure. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a polymer heat sink and a preparation method thereof to solve the technical problems of poor heat dissipation effect and low mechanical strength in the prior art.

[0005] To achieve the above objectives, one of the technical solutions adopted in this application is to provide a polymer vapor chamber, comprising:

[0006] The heat sink body includes a bottom plate, side walls, and support columns. The support columns are arranged on the bottom plate. The side walls are arranged around the outer periphery of the bottom plate. The bottom plate and the side walls enclose a receiving groove, which serves as a steam channel.

[0007] A liquid wick for accommodating liquid working medium, the liquid wick being disposed on the bottom plate and located within the accommodating groove, the liquid wick being provided with grooves arranged in an array, the groove walls of which are embedded with high thermal rate metal wires, the end surface of one end of the high thermal rate metal wires being flush with or protruding from the groove walls of the grooves, and the liquid wick being injection molded from a thermoplastic polymer;

[0008] and a cover plate, which is arranged on the heat spreader body and connected to the support column to seal the receiving groove.

[0009] To achieve the above-mentioned purpose, the second technical solution adopted in this application is to provide a method for preparing a polymer vapor chamber, comprising the following steps:

[0010] providing a wire mesh and a thermoplastic polymer fluid;

[0011] Make a mold: Make a mold according to the structure of the heat sink body described above;

[0012] Embedding wire mesh: embedding the metal wire mesh into the cavity of the mold;

[0013] Injection molding: injecting a thermoplastic polymer fluid into the mold cavity, and forming the above-mentioned vapor chamber body after the thermoplastic polymer fluid is solidified; and

[0014] Processing grooves: An array of grooves is processed on the top surface of the bottom plate of the heat spreader body to form the liquid absorbent core described above.

[0015] In one embodiment, the groove processing step further includes:

[0016] Laser processing is adopted to cut the metal wire mesh so as to form a composite material wall groove structure composed of broken and curled metal wire ends and thermoplastic polymer.

[0017] In one embodiment, the grooves are distributed in a longitudinal array;

[0018] And / or, the grooves are distributed in a transverse array.

[0019] In one embodiment, the length of the wire mesh is greater than or equal to the length of the base plate;

[0020] And / or, the width of the metal mesh is greater than or equal to the width of the base plate.

[0021] In one embodiment, the step of embedding the wire mesh specifically includes:

[0022] The metal mesh is embedded in the mold cavity and is located on the top surface of the base plate. The edge of the metal mesh is protruded outside the base plate and presses the periphery of the base plate to prevent the metal mesh from being deflected when the thermoplastic polymer fluid is injected into the mold cavity.

[0023] In one embodiment, the injection molding step further includes: cutting off the portion of the metal mesh exposed outside the periphery of the bottom plate.

[0024] In one embodiment, the pore size of the metal mesh is greater than 50×50 microns, so that the thermoplastic polymer fluid can enter and fill the metal mesh.

[0025] In one embodiment, the wire mesh is provided with multiple layers.

[0026] In one embodiment, the thermoplastic polymer is a combination of one or more of polyurethane, nylon, polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyethylene terephthalate, and polyoxymethylene;

[0027] And / or, the metal wire mesh is a high thermal rate metal wire mesh, and the metal wire mesh is one of a copper wire mesh and an aluminum wire mesh.

[0028] In one embodiment, a sealing step is further included, wherein the sealing step includes:

[0029] The cover plate is placed on the side wall, so that the support column is connected to the cover plate, and a heat spreader cavity is formed between the heat spreader body and the cover plate;

[0030] Vacuuming to remove the air from the cavity of the vapor chamber;

[0031] Liquid injection: injecting liquid working medium into the cavity of the heat sink, and the liquid working medium will be automatically absorbed by the liquid wick; and

[0032] Seal to form a polymer vapor chamber.

[0033] The addition of high-heat-rate metal wire forms a tight whole with the thermoplastic polymer, which can enhance the strength of the liquid-absorbing core structure and make it less prone to damage; more importantly, the grooved liquid-absorbing core structure on the wall of the thermoplastic polymer and metal wire composite material allows heat to be directly introduced into the groove through the end face of the metal wire, improving the problem of very low thermal conductivity of the polymer material. The rapidly introduced heat enhances the heat absorption and boiling phase change performance of the liquid working medium in the groove of the evaporation section. The steam after the phase change usually flows to the condensation section above the groove and releases heat to condense the phase change. The condensed liquid working medium is refluxed to the evaporation section inside the groove due to the high capillary force of the grooved liquid-absorbing core structure on the wall of the polymer and metal wire composite material (the groove makes the originally smooth polymer end face become rough, thereby greatly improving the capillary force), and the cycle is repeated; greatly improving the heat dissipation performance of the polymer heat spreader. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] Figure 1 An exploded schematic diagram of a polymer vapor chamber provided in an embodiment of the present application;

[0036] Figure 2The microstructure of the absorbent core provided in the embodiment of the present application Figure 1 ;

[0037] Figure 3 The microstructure of the absorbent core provided in the embodiment of the present application Figure 2 ;

[0038] Figure 4 A schematic diagram of the preparation process of a polymer vapor chamber provided in an embodiment of the present application;

[0039] Figure 5 A flow chart of a method for preparing a polymer vapor chamber provided in an embodiment of the present application;

[0040] Figure 6 for Figure 5 A complete flow chart of the method is shown.

[0041] Wherein, description of the accompanying drawings:

[0042] 10. Vapor chamber body; 11. Bottom plate; 12. Side wall; 13. Support column; 100. Receiving groove;

[0043] 20. wick; 21. wire mesh; 200. groove;

[0044] 30. Cover plate;

[0045] 40. Mold. DETAILED DESCRIPTION

[0046] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0047] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0048] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0049] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0050] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0051] References to "one embodiment" or "some embodiments" in the present specification mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized. "Multiple" means two or more.

[0052] It should be understood that the size of the serial numbers of the steps in the embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0053] The present application provides a polymer heat sink, such as Figure 1 As shown, the heat spreader body 10 includes a liquid wick 20 and a cover plate 30; the heat spreader body 10 includes a bottom plate 11, a side wall 12 and a support column 13, one end of the support column 13 is connected to the bottom plate 11, and the other end of the support column 13 is connected to the cover plate 30. The side wall 12 is arranged around the outer periphery of the bottom plate 11, and the bottom plate 11 and the side wall 12 enclose a receiving groove 100, which serves as a steam channel;

[0054] The wick 20 is disposed on the bottom plate 11 and is located within the receiving tank 100. The wick 20 has grooves 200 arranged in an array. High-heat-rate metal wires are embedded in the groove walls of the grooves 200. The end surface of one end of the high-heat-rate metal wire is flush with the groove wall of the groove 200, or the end surface of one end of the high-heat-rate metal wire protrudes from the groove wall of the groove 200. The wick 20 is injection-molded using a thermoplastic polymer and is used to hold a liquid working medium.

[0055] The cover plate 30 is disposed on the vapor chamber body 10 , ie, is disposed on the side wall 12 and connected to the support column 13 to seal the receiving tank 100 .

[0056] In applications, such as Figure 2 and Figure 3 As shown, the addition of high thermal rate metal wire forms a tight whole with the thermoplastic polymer, which can enhance the strength of the absorbent core 20 structure and make it less likely to be damaged.

[0057] More importantly, the high thermal rate metal wire embedded in the groove wall of the groove 200 and the liquid absorption core 20 formed by injection molding of the thermoplastic polymer form a groove 200 structure of the composite material wall, so that heat can be directly introduced into the groove 200 through the end face of the high thermal rate metal wire, improving the problem of low thermal conductivity of the polymer material. The rapidly introduced heat enhances the heat absorption and boiling phase change performance of the liquid working medium in the evaporation section groove 200. The steam after the phase change usually flows to the condensation section above the groove 200 and releases heat and condenses to change phase. The condensed liquid working medium is refluxed to the evaporation section inside the groove 200 due to the high capillary force of the liquid absorption core 20 structure of the polymer and metal wire composite material wall groove 200 (the groove 200 makes the originally smooth polymer end face become rough, thereby greatly improving the capillary force), and the cycle is repeated; the heat dissipation performance of the polymer heat spreader is greatly improved.

[0058] In practice, both the vapor chamber body 10 and the wick 20 are injection molded from thermoplastic polymers, further leveraging their lightweight and flexible properties. Thermoplastic polymers are linear or slightly branched polymers that can be repeatedly heated and melted, molded in a softened or fluidized state, and retain the shape of the mold 40 after cooling. These polymers include polyethylene, polyvinyl chloride, nylon, and polyurethane. High-heat-rate metal wires include copper and aluminum wires.

[0059] In application, the support columns 13 are arranged in an array, so as to prop up the cover plate 30, preventing the polymer heat spreader bottom plate 11 or the cover plate 30 from collapsing, or excessive expansion and bulging caused by internal high pressure, thereby preventing internal collapse and external bulging.

[0060] The present application also provides a method for preparing a polymer vapor chamber. Figures 4 to 6 , including the following steps:

[0061] S01 provides a metal wire mesh 21 and a thermoplastic polymer fluid;

[0062] S02: Making a mold 40: Making a mold 40 according to the structure of the vapor chamber body 10. The mold 40 has a cavity for forming the bottom plate 11, the side wall 12, and the support column 13;

[0063] S03 Embedding the wire mesh: embedding the metal wire mesh 21 into the cavity of the mold 40;

[0064] S04 Injection molding: injecting a thermoplastic polymer fluid into the cavity of the mold 40, and forming the above-mentioned heat spreader body 10 after the thermoplastic polymer fluid is solidified;

[0065] S05 Processing the grooves 200 : Take out the vapor chamber body 10 , and process the grooves 200 arranged in an array on the top surface of the bottom plate 11 to form the liquid wick 20 .

[0066] In practice, the metal mesh 21 is woven from high-heat-rate metal wires; specifically, the metal mesh 21 is copper mesh, aluminum mesh, or the like. This effectively utilizes the capillary force of the copper mesh or aluminum mesh, thereby enhancing the capillary force of the wick 20 and allowing the liquid working medium condensed in the polymer vapor chamber to flow back to the evaporation section.

[0067] In one embodiment, the step S05 of processing the groove 200 further includes:

[0068] Laser processing and cutting of the wire mesh 21 creates a composite groove 200 structure composed of broken and curled wire ends and thermoplastic polymer. Laser cutting roughens the originally smooth thermoplastic polymer surface, enhancing capillary force. This capillary force is further enhanced by the cut wire mesh 21. Furthermore, cutting the wire mesh 21 causes the wires to curl, creating an even rougher groove 200 wall.

[0069] In application, other cutting methods may be used; or the wall surface of the groove 200 may be made rougher by friction.

[0070] In use, when cutting the metal mesh 21, ensure that the bottom plate 11 is not cut through to prevent air or liquid leakage.

[0071] In one embodiment, the grooves 200 are arranged in a longitudinal array and in a transverse array. In another embodiment, the grooves 200 are arranged only in a longitudinal array, or only in a transverse array. The crisscrossing grooves 200 greatly increase the roughness of the groove 200 wall surface, causing more metal wire ends to curl, thereby increasing the thermal conductivity of the wick 20 and further improving the heat dissipation efficiency of the polymer vapor chamber.

[0072] In one embodiment, Figure 4As shown, the length of the wire mesh 21 is greater than or equal to the length of the base plate 11, and the width of the wire mesh 21 is greater than or equal to the width of the base plate 11. That is, the horizontal dimension of the wire mesh 21 is greater than or equal to the horizontal dimension of the base plate 11. This arrangement facilitates positioning of the wire mesh 21. The portion of the wire mesh 21 protruding from the base plate 11 serves as a positioning mechanism to prevent the thermoplastic polymer fluid from being displaced from the wire mesh 21 when injected into the mold cavity 40, causing the wire mesh 21 to collapse. In other embodiments, only the length of the wire mesh 21 is greater than or equal to the length of the base plate 11, or only the width of the wire mesh 21 is greater than or equal to the width of the base plate 11. As long as the positioning mechanism can be used to prevent the thermoplastic polymer fluid from being displaced from the wire mesh 21 when injected into the mold cavity 40, it is sufficient.

[0073] In one embodiment, Figure 4 As shown, the S03 screen embedding step specifically includes:

[0074] The wire mesh 21 is embedded in the cavity of the mold 40 and is located on the top surface of the base plate 11. The edge of the wire mesh 21 is protruding from the outer periphery of the base plate 11, and the wire mesh 21 is pressed against the outer periphery of the base plate 11 to prevent the wire mesh 21 from being deflected when the thermoplastic polymer fluid is injected into the cavity of the mold 40.

[0075] During use, the wire mesh 21 is embedded in the mold cavity of the mold 40 so that the wire mesh 21 is located on the top surface of the thickness region of the base plate 11. The edge of the wire mesh 21 protrudes from the base plate 11, thereby ensuring that the portion of the wire mesh 21 located on the base plate 11 does not collapse downward. This serves to position the wire mesh 21 and prevent it from being displaced when the thermoplastic polymer fluid is injected into the mold cavity 40. In other embodiments, the wire mesh 21 may be provided in two layers to enhance its structural strength and prevent the central portion of the wire mesh 21 from collapsing downward.

[0076] In one embodiment, the injection molding step S04 further includes: cutting off the portion of the metal mesh 21 exposed outside the periphery of the bottom plate 11. The molding is more beautiful.

[0077] In one embodiment, the pore size of the wire mesh 21 is greater than 50 x 50 microns, allowing the thermoplastic polymer fluid to enter and fill the wire mesh 21. Specifically, the pore size refers to the horizontal length and width. In other embodiments, the pores may be circular or elliptical, as long as the pore size is sufficient to allow the thermoplastic polymer fluid to pass through.

[0078] In application, the hole size of the metal mesh 21 is 0.1×0.1 mm and the thickness is 0.25 mm; this ensures that the thermoplastic polymer fluid can enter and fill the holes of the metal mesh 21 .

[0079] In one embodiment, the thermoplastic polymer is one or more of polyurethane, nylon, polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyethylene terephthalate, and polyoxymethylene. These polymers can be repeatedly heated and melted, molded in a softened or fluid state, and maintain the shape of the mold 40 after cooling.

[0080] In one embodiment, the metal wire mesh 21 is a high thermal rate metal wire mesh 21 , and the metal wire mesh 21 is a copper wire mesh or an aluminum wire mesh.

[0081] In one embodiment, the above-mentioned preparation method further includes a sealing step S06, which includes:

[0082] S601: Install the cover plate 30 on the side wall 12, connect the support column 13 to the cover plate 30, and form a vapor chamber cavity between the vapor chamber body 10 and the cover plate 30;

[0083] S602: vacuuming to remove the air from the heat sink cavity;

[0084] S603: Liquid injection, injecting liquid working medium into the cavity of the heat sink, and the liquid working medium is automatically absorbed by the liquid wick 20;

[0085] S604 is sealed to form a polymer heat sink.

[0086] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0087] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A polymer vapor chamber, characterized in that: include: The heat sink body includes a bottom plate, side walls, and support columns. The support columns are arranged on the bottom plate. The side walls are arranged around the outer periphery of the bottom plate. The bottom plate and the side walls enclose a receiving groove, which serves as a steam channel. A liquid wick for accommodating liquid working medium, the liquid wick being disposed on the bottom plate and located within the accommodating groove, the liquid wick being provided with grooves arranged in an array, the groove walls of which are embedded with high thermal rate metal wires, the end surface of one end of the high thermal rate metal wires being flush with or protruding from the groove walls of the grooves, and the liquid wick being injection molded from a thermoplastic polymer; and a cover plate, which is arranged on the heat spreader body and connected to the support column to seal the receiving groove.

2. A method for preparing a polymer vapor chamber, characterized in that: The steps include: providing a wire mesh and a thermoplastic polymer fluid; Making a mold: Making a mold according to the structure of the vapor chamber body according to claim 1; Embedding wire mesh: embedding the metal wire mesh into the cavity of the mold; Injection molding: injecting a thermoplastic polymer fluid into the mold cavity of the mold, and forming the vapor chamber body according to claim 1 after the thermoplastic polymer fluid is solidified; Processing grooves: grooves arranged in an array are processed on the top surface of the bottom plate of the heat spreader body to form the liquid absorbent core as described in claim 1.

3. The preparation method according to claim 2, wherein The groove processing step also includes: Laser processing is adopted to cut the metal wire mesh so as to form a composite material wall groove structure composed of broken and curled metal wire ends and thermoplastic polymer.

4. The preparation method according to claim 2, wherein The grooves are distributed in a longitudinal array; And / or, the grooves are distributed in a transverse array.

5. The preparation method according to claim 2, wherein The length of the metal mesh is greater than or equal to the length of the base plate; And / or, the width of the metal mesh is greater than or equal to the width of the base plate.

6. The preparation method according to claim 2, wherein The step of embedding the screen specifically includes: The metal mesh is embedded in the mold cavity and is located on the top surface of the base plate. The edge of the metal mesh is protruded outside the base plate and presses the periphery of the base plate to prevent the metal mesh from being deflected when the thermoplastic polymer fluid is injected into the mold cavity.

7. The preparation method according to claim 6, wherein The injection molding step further includes: cutting off the portion of the metal mesh exposed outside the periphery of the bottom plate.

8. The preparation method according to claim 2, wherein The pore size of the metal mesh is greater than 50×50 microns, so that the thermoplastic polymer fluid can enter and fill the metal mesh.

9. The preparation method according to any one of claims 2 to 8, characterized in that The thermoplastic polymer is one or more of polyurethane, nylon, polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polystyrene, polymethyl methacrylate, polytetrafluoroethylene, polyethylene terephthalate and polyoxymethylene; And / or, the metal wire mesh is a high thermal rate metal wire mesh, and the metal wire mesh is one of a copper wire mesh and an aluminum wire mesh.

10. The preparation method according to any one of claims 2 to 8, characterized in that: It also includes a closed production step, which includes: The cover plate is placed on the side wall, so that the support column is connected to the cover plate, and a heat spreader cavity is formed between the heat spreader body and the cover plate; Vacuuming to remove the air from the cavity of the vapor chamber; Liquid injection: injecting liquid working medium into the cavity of the heat sink, and the liquid working medium will be automatically absorbed by the liquid wick; and Seal to form a polymer vapor chamber.

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