CN112367797A

CN112367797A - Heat conduction structure, manufacturing method thereof and mobile device

Info

Publication number: CN112367797A
Application number: CN202010585665.9A
Authority: CN
Inventors: 萧毅豪; 何铭祥
Original assignee: Henan Sili New Material Technology Co ltd
Current assignee: Henan Sili New Material Technology Co ltd
Priority date: 2019-06-28
Filing date: 2020-06-24
Publication date: 2021-02-12
Also published as: TWI692610B; TW202100931A

Abstract

The invention discloses a heat conduction structure, a manufacturing method thereof and a mobile device. The invention discloses a heat conduction structure which comprises a heat conduction unit, a first heat conduction layer, a metal microstructure, a second heat conduction layer and a working fluid. The closed cavity of the heat conducting unit is provided with a bottom surface and a top surface which are opposite, and the first heat conducting layer is arranged on the bottom surface and/or the top surface of the closed cavity. The metal microstructure is arranged on the first heat conduction layer, so that the first heat conduction layer is positioned between the metal microstructure and the bottom surface and/or the top surface. The second heat conduction layer is arranged on one side, far away from the first heat conduction layer, of the metal microstructure. The working fluid is arranged in the closed cavity of the heat conduction unit, wherein the working fluid comprises a carbon material. The invention also discloses a manufacturing method of the heat conduction structure and a mobile device.

Description

Heat conduction structure, manufacturing method thereof and mobile device

Technical Field

The invention discloses a heat conduction structure, a manufacturing method thereof and a mobile device with the heat conduction structure.

Background

With the development of technology, the design and development of mobile devices are not optimized for thin and high performance. In the case of high-speed operation and thin-type operation, the computing chip (e.g., cpu) inside the mobile device must provide high performance speed, and generate relatively high heat (temperature may even exceed 100 ℃), which may cause permanent damage to components or the mobile device if the heat is not conducted to the outside.

In order to avoid overheating of the device, the prior art generally provides a heat dissipation structure for dissipating heat generated by the mobile device by conduction, convection, radiation, and the like. In addition, as the mobile device is designed to be thinner and lighter, the space for disposing various electronic components therein is also narrow, and the embedded heat dissipation structure must conform to the design of the narrow space.

Therefore, how to develop a heat conduction structure more suitable for the requirement of high power components or devices, which can be suitable for the heat dissipation requirement of light and thin mobile devices, has been one of the targets continuously pursued by the related manufacturers.

Disclosure of Invention

The invention aims to provide a heat conduction structure, a manufacturing method thereof and a mobile device. The heat conduction structure has higher heat conduction efficiency, can quickly conduct out heat energy generated by a heat source, and can meet the heat dissipation requirement of a light and thin mobile device.

To achieve the above object, a heat conduction structure according to the present invention includes a heat conduction unit, a first heat conduction layer, a metal microstructure, a second heat conduction layer, and a working fluid. The heat conduction unit forms a closed cavity which is provided with a bottom surface and a top surface which are opposite. The metal microstructure is arranged on the first heat conduction layer, so that the first heat conduction layer is positioned between the metal microstructure and the bottom surface and/or the top surface. The second heat conduction layer is arranged on one side, far away from the first heat conduction layer, of the metal microstructure. The working fluid is arranged in the closed cavity of the heat conduction unit, wherein the working fluid comprises a carbon material.

In one embodiment, the first thermally conductive layer or the second thermally conductive layer covers at least a portion of a surface of the metal microstructure.

In one embodiment, the first heat conduction layer, the metal microstructure and the second heat conduction layer form a stacked structure, the stacked structure is divided into at least two sections along the long axis direction of the heat conduction unit, the at least two sections comprise a first section and a second section, and the first heat conduction layer and the second heat conduction layer in the first section are at least partially made of different materials from the first heat conduction layer and the second heat conduction layer in the second section.

In one embodiment, the metal microstructures are in the form of metal mesh, metal powder, or metal particles, or a combination thereof.

In one embodiment, the material of the first thermally conductive layer or the second thermally conductive layer comprises graphene, graphite, carbon nanotubes, aluminum oxide, zinc oxide, titanium oxide, or boron nitride, or a combination thereof.

In one embodiment, the heat conduction structure further comprises a third heat conduction layer disposed on a side of the second heat conduction layer away from the metal microstructure.

In one embodiment, the first heat conduction layer, the metal microstructure, the second heat conduction layer and the third heat conduction layer form a stacked structure, the stacked structure is divided into at least two sections along the long axis direction of the heat conduction unit, the at least two sections comprise a first section and a second section, and the first heat conduction layer, the second heat conduction layer and the third heat conduction layer in the first section are at least partially made of different materials from the first heat conduction layer, the second heat conduction layer and the third heat conduction layer in the second section.

In one embodiment, the third thermally conductive layer includes a plurality of nanotubes having an axial direction perpendicular to a surface of the second thermally conductive layer.

In one embodiment, the heat conduction structure further comprises a fourth heat conduction layer disposed at a position in the inner surface of the closed cavity body where the first heat conduction layer, the metal microstructure and the second heat conduction layer are not located.

In one embodiment, the carbon material is graphite, graphene, carbon nanotubes, carbon spheres, or carbon wires, or a combination thereof; the percentage of the carbon material in the working fluid is 0.0001% or more and 2% or less.

To achieve the above object, a mobile device according to the present invention includes a heat source and the above heat conduction structure, and one end of the heat conduction structure contacts the heat source.

To achieve the above object, a method for manufacturing a heat conduction structure according to the present invention includes: forming a first heat conductive layer on the first substrate and/or the second substrate; forming a metal microstructure on the first substrate and/or the second substrate, and enabling the first heat conduction layer to be located between the metal microstructure and the first substrate and/or the second substrate; forming a second heat conduction layer on one side of the metal microstructure far away from the first heat conduction layer; combining the first substrate and the second substrate to form a heat conducting unit, wherein the heat conducting unit forms a closed cavity; and injecting a working fluid into the closed cavity through the gap of the heat conducting unit, wherein the working fluid comprises a carbon material.

To achieve the above object, another method for manufacturing a heat conduction structure according to the present invention includes forming a first heat conduction layer on a metal microstructure; forming a second heat conduction layer on one side of the metal microstructure far away from the first heat conduction layer; arranging a metal microstructure provided with a first heat conduction layer and a second heat conduction layer on the first substrate and/or the second substrate, and enabling the first heat conduction layer to be located between the metal microstructure and the first substrate and/or the second substrate; combining the first substrate and the second substrate to form a heat conducting unit, wherein the heat conducting unit forms a closed cavity; and injecting a working fluid into the closed cavity through the gap of the heat conducting unit, wherein the working fluid comprises a carbon material.

In one embodiment, before the step of combining the first substrate and the second substrate, the method further comprises the steps of: and forming a third heat conduction layer on the side of the second heat conduction layer far away from the metal microstructure.

In one embodiment, before the step of combining the first substrate and the second substrate, the method further comprises the steps of: a fourth heat conduction layer is formed on the inner surface of the closed cavity body at a position without the first heat conduction layer, the metal microstructure, the second heat conduction layer and the third heat conduction layer.

In one embodiment, before the step of combining the first substrate and the second substrate, the method further comprises the steps of: and forming a fourth heat conduction layer at the position without the first heat conduction layer, the metal microstructure and the second heat conduction layer in the inner surface of the closed cavity.

In view of the above, in the heat conduction structure, the manufacturing method thereof, and the mobile device of the present invention, the first heat conduction layer and the second heat conduction layer are disposed on two sides of the metal microstructure inside the heat conduction structure, and the working fluid including the carbon material is disposed in the closed cavity of the heat conduction unit, so that the hydrophilicity of the metal microstructure can be increased, the reflux rate of the liquid working fluid in the metal microstructure can be increased, the circulation efficiency of the working fluid can be increased, and the temperature equalization effect and the heat conduction effect of the heat conduction structure are better. Therefore, the heat conduction structure of the invention has higher heat conduction efficiency, can quickly conduct out the heat energy generated by the heat source, and can also be suitable for the heat dissipation requirement of a light and thin mobile device.

In some embodiments, the heat conduction structure of the present invention may further include a third heat conduction layer disposed on a side of the second heat conduction layer away from the metal microstructure, where the third heat conduction layer may increase the heat conduction efficiency of the heat conduction structure, and may further increase the coverage and hydrophilicity, and may also increase the protection of the metal microstructure from corrosion or oxidation.

Drawings

Fig. 1A is a schematic view of a heat conduction structure according to an embodiment of the present invention.

FIG. 1B is a schematic cross-sectional view of the thermal conduction structure of FIG. 1A taken along a section line A-A.

FIG. 1C is a schematic cross-sectional view of the thermally conductive structure of FIG. 1A taken along an X-X cut line.

Fig. 1D and fig. 1E are schematic diagrams of different embodiments of the heat conduction structure of fig. 1B, wherein the first heat conduction layer and the second heat conduction layer are respectively disposed on two sides of the metal microstructure.

FIG. 1F is a schematic cross-sectional view of a heat conduction structure according to another embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of a heat conduction structure according to another embodiment of the present invention.

Fig. 3A, fig. 3B and fig. 3C are schematic cross-sectional views of a heat conduction structure according to another embodiment of the present invention.

Fig. 4 is a schematic diagram of a mobile device according to an embodiment of the invention.

Fig. 5A and 5B are schematic views illustrating different manufacturing processes of the heat conduction structure according to the present invention.

Fig. 6A to 6E are schematic views illustrating a manufacturing process of a heat conduction structure according to an embodiment of the invention.

Fig. 7A and 7B are partial schematic views illustrating another process of manufacturing a heat conduction structure according to an embodiment of the present invention.

Detailed Description

The heat conduction structure, the method of manufacturing the same, and the mobile device according to some embodiments of the present invention will be described below with reference to the accompanying drawings, in which like components are described with like reference numerals. The components appearing in the following examples are illustrative only and do not represent actual proportions or dimensions.

The heat conduction structure can have higher heat conduction efficiency, can quickly conduct out heat energy generated by a heat source, and can meet the heat dissipation requirement of a light and thin mobile device. The heat conduction structure can be arranged in the mobile device, and one end of the heat conduction structure can be contacted with the heat source so as to transfer the heat generated by the heat source to the other end of the heat conduction structure through the guidance of the heat conduction structure, thereby avoiding the mobile device from being halted or burnt down due to the high temperature of the heat source. In some embodiments, the heat source may include, for example but not limited to, a Central Processing Unit (CPU), a memory chip (card), a display chip (card), a panel, or a power component of a mobile device, or other elements, units, or components that generate high temperature heat energy. In addition, the mobile device may be, but not limited to, a mobile phone, a notebook computer, a tablet computer, a television, or a display-related mobile electronic device, or other fields of mobile devices.

In addition, the heat conduction structure of the present application can be a temperature equalization plate or a heat pipe (or heat pipe). The heat pipe is a circular pipe, and the heat conduction mode of the heat pipe is a one-dimensional and linear heat conduction mode; the temperature equalizing plate is a two-dimensional and surface heat conduction mode, and is a high-performance heat dissipation device capable of quickly conducting a local heat source to the other side of the flat plate, so that the problem of heat dissipation under more severe conditions can be solved, and higher heat dissipation efficiency is achieved. The heat conduction structure of the following embodiments is exemplified by a flat temperature-uniforming plate, but is still applicable to a heat pipe. In addition, in order to explain the internal structure of the heat conduction structure, the length and shape shown in the following drawings are only schematic, and in practical applications, the heat conduction structure may be bent in a horizontal direction and/or a vertical direction, and the bending manner may be determined according to a heat source of the mobile device to be radiated and an internal space thereof.

Referring to fig. 1A to 1C, fig. 1A is a schematic view of a heat conduction structure according to an embodiment of the present invention, fig. 1B is a schematic cross-sectional view of the heat conduction structure of fig. 1A taken along a-a section line, and fig. 1C is a schematic cross-sectional view of the heat conduction structure of fig. 1A taken along an X-X section line. Here, the direction along the X-X cut line is the long axis direction of the heat conduction structure (or the heat conduction unit).

As shown in fig. 1A to 1C, the heat conduction structure 1 may include a heat conduction unit 11, a first heat conduction layer 12, a metal microstructure 13, at least one second heat conduction layer 14, and a working fluid 15.

The heat conducting unit 11 is surrounded to form a closed cavity 111, and the closed cavity 111 has a bottom surface B and a top surface T opposite to each other. In some embodiments, the heat conduction structure 1 may be a relatively thin plate, and the thickness thereof may be less than 0.4mm, for example, 0.35mm, so as to meet the heat conduction and dissipation requirements of the thin mobile device. The opposite ends of the heat conducting unit 11 are respectively used as a heat source end H (heat source side) and a cooling end C (cooling side). As shown in fig. 1A and 1C, the heat source end (side) H may be one (side) of the two sides of the heat conducting unit 11 close to the heat source, and the cooling end (side) C may be one (side) of the two sides of the heat conducting unit 11 far from the heat source. In addition, the heated portion of the closed cavity 111 of the heat conducting unit 11 may be referred to as an evaporation region, and the other side opposite to the evaporation region may be referred to as a condensation region, and the working fluid 15 may absorb heat in the evaporation region to vaporize and rapidly expand to the whole closed cavity 111, and emit heat in the condensation region to condense into a liquid state, and then flow back to the evaporation region, and so on.

The heat conducting unit 11 has a structural function of withstanding internal and external pressure differences, and is made of a dielectric material capable of conducting heat into and out of the heat conducting unit. The heat conducting unit 11 may be formed by welding a plurality of metal plates or may be a single member integrally formed. In the present embodiment, two pieces of recessed metal plates (e.g., the first substrate 10a and the second substrate 10B shown in fig. 1B) are correspondingly connected (e.g., welded) as an example. The material of the heat conducting unit 11 is preferably metal, such as but not limited to high heat conducting metal materials including copper, aluminum, iron, silver, gold, etc. This embodiment is copper.

The first thermally conductive layer 12 is disposed on the bottom surface B and/or the top surface T of the closed cavity 111. The first heat conductive layer 12 of the present embodiment is disposed on the bottom surface B of the closed cavity 111 as an example. In some embodiments, the first thermal conductive layer 12 can also be disposed on the top surface T of the closed cavity 111; alternatively, the first heat conductive layer 12 is disposed on both the bottom surface B and the top surface T of the closed cavity 111.

The metal microstructure 13 is disposed on the first heat conductive layer 12, such that the first heat conductive layer 12 is located between the metal microstructure 13 and the bottom surface B and/or the top surface T. In the present embodiment, the metal microstructure 13 is disposed on the bottom surface B having the first heat conductive layer 12, so that the first heat conductive layer 12 can be located between the metal microstructure 13 and the bottom surface B. The metal microstructures 13 may be capillary structures (wicks) in the form of metal mesh, metal powder, metal particles (including nano-metal particles), metal pillars (such as cylinders, pyramids, or square pillars), or combinations thereof, or structures in which a metal material covers a non-metal material, or other forms that increase the contact surface area of the heat conducting layer, such as but not limited to metal materials with high thermal conductivity including copper, aluminum, iron, silver, gold, or combinations thereof, or other suitable materials. The capillary structure (metal microstructure 13) may have different designs, and there are four common designs, which are: grooved, mesh (woven), fiber, and sintered. Since the metal microstructure 13 is disposed on the inner side of the heat conducting unit 11, the liquid working fluid 15 condensed after the heat of the gaseous working fluid 15 is dissipated to the outside of the heat conducting unit 11 in the condensing region (cooling end C) can flow back along the metal microstructure 13 through the bottom B of the heat conducting unit 11 (flow direction D2 in fig. 1C) to the evaporation region (heat source end H), so that the working fluid 15 can continuously circulate back in the heat conducting unit 11. The metal microstructure 13 of the present embodiment is made of copper mesh as an example.

At least one second heat conductive layer 14 is disposed on a side of the metal microstructure 13 away from the first heat conductive layer 12. As shown in fig. 1B, the second heat conductive layer 14 is disposed on the metal microstructure 13 by one layer, such that the metal microstructure 13 is located between the second heat conductive layer 14 and the first heat conductive layer 12 (fig. 1C indicates a stacked structure of the second heat conductive layer 14, the metal microstructure 13 and the first heat conductive layer 12 by the reference symbol "S"). The first and second thermally

conductive layers

12 and 14 may include a material with a high thermal conductivity, which may be an organic material or an inorganic material, the organic material may include a carbon material, such as but not limited to graphite, graphene, carbon nanotubes, carbon spheres, carbon wires, and the like, and the inorganic material may include a metal with a high thermal conductivity, such as but not limited to a metal with a high thermal conductivity, or a combination thereof.

In some embodiments, the first thermal conductive layer 12 or the second thermal conductive layer 14 covers at least a portion of the surface of the metal microstructure 13; in some embodiments, the coverage of the first thermal conductive layer 12 or the second thermal conductive layer 14 on the surface of the metal microstructure 13 can be greater than or equal to 0.001% and less than or equal to 100% (0.001% ≦ 100%, 100% indicating coverage on all surfaces). In some embodiments, the coverage of the first thermal conductive layer 12 or the second thermal conductive layer 14 on the surface of the metal microstructure 13 can be greater than or equal to 5% and less than or equal to 100% (5% ≦ 100%), such as 7%, 10%, 12%, 15%, 20%, 25%, 30%, …, or 90%, etc.; in some embodiments, the coverage rate of the first thermal conductive layer 12 or the second thermal conductive layer 14 covering the surface of the metal microstructure 13 can be greater than or equal to 0.001%, and less than or equal to 5% (0.001% ≦ 5%), such as 0.005%, 0.01%, 0.02%, 0.5%, 1%, …, or 3%, and the like, without limitation. In addition, the above-mentioned feature that the first heat conduction layer 12 or the second heat conduction layer 14 covers at least a portion of the surface of the metal microstructure 13 and the coverage rate thereof can also be applied to other embodiments of the present invention.

In some embodiments, the materials of first thermal conductive layer 12 and second thermal conductive layer 14 include, for example and without limitation, graphene, graphite, multi-walled carbon nanotubes, aluminum oxide, zinc oxide, titanium oxide, or boron nitride, or combinations thereof, or other highly thermally conductive inorganic or organic materials. The organic material may include 0D (dimension), 1D, 2D, or 3D. Wherein the 0D material is, for example, but not limited to, graphene quantum dots; 1D materials such as, but not limited to, carbon nanotubes; the 2D material is, for example, but not limited to, graphene nanoplatelets or molybdenum disulfide (MoS)₂) (ii) a And the 3D material is, for example and without limitation, graphite. Preferred materials for the first and second thermally

conductive layers

12, 14 are graphene, or carbon nanotubes, or a combination thereof. In the present embodiment, the first thermal conductive layer 12 and the second thermal conductive layer 14 are made of the same material and are made of graphene. In some embodiments, the first thermal conductive layer 12 or the second thermal conductive layer 14 can cover a portion of the surface or the entire surface of the metal microstructure 13. In some embodiments, the first and second thermally

conductive layers

12 and 14 may each be a Graphene Thermal Film (GTF).

Since the graphene materials (the first thermal conductive layer 12 and the second thermal conductive layer 14) have good xy-plane thermal conductivity, the thermal conduction efficiency of the metal microstructure 13 can be increased. In addition, the graphene material (the first thermal conductive layer 12 and the second thermal conductive layer 14) can also increase the hydrophilicity of the metal microstructure 13 (e.g., copper mesh), and can protect the metal microstructure 13 from oxidation and corrosion. The better hydrophilicity indicates that the smaller the contact angle (contact angle), the more easily the working fluid 15 in the closed cavity 111, such as water and water vapor, can be continuously attached to the surface of graphene, so that water is easier to evaporate, water vapor is easier to condense, the circulating reflux speed can be faster, and heat energy can be more quickly conducted. It should be noted that in this embodiment, the second heat conductive layer 14 is disposed on a side of the metal microstructure 13 away from the first heat conductive layer 12, and in different embodiments, a plurality of layers of the second heat conductive layer 14 (for example, a plurality of graphene film layers) may also be disposed on the metal microstructure 13, which is not limited in this application. In addition, in different embodiments, the materials of the first thermal conductive layer 12 and the second thermal conductive layer 14 may also be different.

Referring to fig. 1D and fig. 1E, which are schematic diagrams of different embodiments of the heat conduction structure of fig. 1B having a first heat conduction layer and a second heat conduction layer on two sides of the metal microstructure respectively.

The metal microstructure 13 of fig. 1D is a copper mesh, and the materials of the first heat conduction layer 12 and the second heat conduction layer 14 are graphene as an example. In fig. 1D, a portion of the metal microstructure 13 (copper mesh) is disposed (connected) on a surface of the first substrate 10a, and a plurality of graphene materials (forming the first heat conductive layer 12) are disposed and cover a portion of a lower surface of the metal microstructure 13 and are located between the metal microstructure 13 and the first substrate 10 a. An additional graphene material (forming the second heat conductive layer 14) is disposed on and covers a portion of the upper surface of the metal microstructure 13, so that the metal microstructure 13 can be interposed between the first heat conductive layer 12 and the second heat conductive layer 14.

In addition, the metal microstructure 13 of fig. 1E is copper powder, and the materials of the first heat conduction layer 12 and the second heat conduction layer 14 are still graphene as an example. In fig. 1E, a part of the metal microstructure 13 (copper powder) is disposed (connected) on the surface of the first substrate 10a, and the graphene material (forming the first heat conductive layer 12) is disposed and covers a part of the lower surface of the metal microstructure 13 and is located between the metal microstructure 13 and the first substrate 10 a. An additional graphene material (forming the second heat conductive layer 14) is disposed on and covers a portion of the upper surface of the metal microstructure 13, so that the metal microstructure 13 can be interposed between the first heat conductive layer 12 and the second heat conductive layer 14.

Referring to fig. 1B and fig. 1C, the working fluid 15 is filled and disposed in the closed cavity 111 of the heat conducting unit 11. Since the heat source end H of the heat conducting structure 1 will be in contact with the heat source, heat will be conducted to the heat source end H of the heat conducting unit 11 (fig. 1C shows heat transfer into the heat source end H by arrows inside the heat source end H), so that the heat source end H has a higher temperature and the working fluid 15 in the heat source end H can be vaporized into a gaseous state. The working fluid 15 may be selected from a refrigerant or other heat-conducting fluid, such as but not limited to Freon (Freon), ammonia, acetone, methanol, ethylene glycol, propylene glycol, Dimethyl sulfoxide (DMSO), or water, and the like, and may be determined according to the type or type of the heat source of the mobile device, as long as the selected working fluid 15 can be vaporized into a gaseous state by the temperature of the heat source in the heat source end H and condensed back to the cooling end C. The working fluid 15 of the present embodiment is water, for example.

It should be noted that, when the refrigerant is selected as the working fluid 15, and before the refrigerant is injected into the heat conducting unit 11, the closed cavity 111 needs to be evacuated to prevent the existence of impurity gases (e.g. air) other than the working fluid 15 inside the heat conducting unit 11, since the impurity gases do not participate in the vaporization-condensation cycle and are called non-condensed gases, the non-condensed gases will not cause the vaporization temperature to rise, and when the heat conducting structure 1 operates, the non-condensed gases will occupy a certain volume of space inside the cavity of the heat conducting unit 11, which will affect the heat conducting performance of the heat conducting structure 1. In addition, the heat conducting structure 1 is connected to the heat source in a manner such as, but not limited to, by a heat conducting paste or a heat dissipating paste, through which the heat source of the mobile device can be connected to the heat source end H of the heat conducting structure 1 to conduct the heat energy of the heat source to the heat source end H of the heat conducting structure 1. In some embodiments, the thermal conductive paste or thermal grease may include a curing agent of a thermally conductive silicone composition, a thermally conductive filler, a silicone resin, an organic peroxide compound, and the like; in some embodiments, the material of the thermal paste or thermal paste may also include an acrylic-type glue material.

In the present embodiment, as shown in fig. 1B and fig. 1C, the working fluid 15 includes a carbon material 151, such as but not limited to graphite, graphene, carbon nanotubes, carbon spheres, or carbon wires, or a combination thereof, so as to increase the heat conduction efficiency. In some embodiments, the percentage of carbon material 151 in the working fluid 15 may be greater than or equal to 0.0001%, and less than or equal to 2% (0.0001% ≦ 2% percentage of carbon material 151). In some embodiments, the percentage of carbon material 151 in the working fluid 15 can be greater than or equal to 0.0001%, and less than or equal to 1.5% (0.0001% to less than or equal to 1.5% of carbon material 151), such as 0.00015%, 0.005%, 0.01%, 0.03%, 0.1%, 0.5%, 1%, or 1.25%, or the like, or other ratios, without limitation. The above percentages are merely exemplary and are not intended to limit the present invention, as long as the carbon material 151 accounts for between 0.0001% and 2% of the working fluid 15, the heat conduction efficiency of the working fluid can be improved, and thus the heat conduction efficiency of the heat conduction structure can be improved. It should be noted that the above-mentioned feature of including the carbon material 151 in the working fluid 15 can also be applied to other embodiments of the present invention.

Therefore, the heat conduction structure 1 can make the heat source end H of the heat conduction unit 11 have a higher temperature when contacting with the heat source, so that the working fluid 15 at the heat source end H can be vaporized into a gaseous state, and the gaseous working fluid 15 will move along the flow path of the closed cavity 111 toward the cooling end C (i.e. along the flow direction D1) to take away the heat generated by the heat source through the working fluid 15; the heat of the working fluid 15 reaching the cooling end C can be dissipated to the outside of the heat conducting unit 11 (the arrow far away from the cooling end C indicates that the heat is dissipated from the cooling end C to the outside). Because the metal microstructure 13 is disposed on the bottom surface B of the heat conducting unit 11, the condensed liquid working fluid 15 can flow back to the heat source end H (flowing to D2) along the metal microstructure 13, so that the working fluid 15 can continuously circulate back to the heat conducting unit 11 to continuously take away the heat from the heat source and dissipate the heat from the cooling end C.

In the embodiment, the first heat conduction layer 12 and the second heat conduction layer 14 are made of graphene, and are respectively disposed on two sides of the metal microstructure 13, so as to increase the hydrophilicity of the metal microstructure 13 (e.g., a copper mesh), thereby increasing the speed at which the gaseous working fluid 15 leaves the metal microstructure 13 and the speed at which the liquid working fluid 15 enters the metal microstructure 13, so that the liquid working fluid 15 can rapidly flow back to the heat source end H through the flow direction D2, thereby increasing the circulation efficiency of the working fluid 15, and making the temperature equalization and the heat conduction effects of the heat conduction structure 1 better. Compared with the conventional temperature equalization plate structure (without the first heat conduction layer 12 and the second heat conduction layer 14), the heat conduction structure 1 of the present embodiment can conduct heat energy from the heat source end H to the cooling end C more rapidly, so as to reduce the temperature difference between the heat source end H and the cooling end C, wherein a smaller temperature difference indicates less obstruction to heat conduction and better heat conduction efficiency.

In addition, in some embodiments, the sum of the thicknesses of the first and second heat

conductive layers

12 and 14 closer to the heat source end H may be greater than the sum of the thicknesses of the first and second heat

conductive layers

12 and 14 farther from the heat source end H. The first thermal conductive layer 12, the metal microstructure 13 and the second thermal conductive layer 14 can be referred to as a stacked structure S. In some embodiments, the thickness of the stacked structure S may be reduced in a stepwise manner. Specifically, please refer to fig. 1F, which is a schematic cross-sectional view of a heat conduction structure according to another embodiment of the present invention. In the case where the thickness of the metal microstructure 13 is not changed, the sum of the thicknesses of the first heat conduction layer 12 and the second heat conduction layer 14 in fig. 1F is decreased in a stepwise manner in the direction along the X-X section line (in the direction along the long axis of the heat conduction unit 11), so that the sum of the thicknesses of the first heat conduction layer 12 and the second heat conduction layer 14 closest to the heat source end H is the largest, and the sum of the thicknesses of the first heat conduction layer 12 and the second heat conduction layer 14 closest to the cooling end C is the smallest in the stacked structure S. The "thickness sum" in the present application may be "the thickness sum of one point", or "the average thickness sum of one small region", without limitation.

Here, the stacking structure S may be divided into at least two sections in the direction along the X-X cut line (i.e., the long axis direction of the heat conducting unit 11), and the at least two sections may include a first section and a second section. Taking fig. 1F as an example, the stacked structure S closest to the heat source end H may be the first section S1, the stacked structure S closest to the cooling end C may be the second section S2 (the sum of the thicknesses of the first section S1 is d1, the sum of the thicknesses of the second section S2 is d3, d1> d3), in some embodiments, the sum of the thicknesses of the first thermal conductive layer 12 and the second thermal conductive layer 14 in the first section S1 may be greater than or equal to 1 nanometer (nm), and less than or equal to 500 micrometers (μm) (1nm ≦ thickness ≦ and ≦ 500 μm), such as 10nm, 500nm, 1 μm, 20 μm, 350 μm, or 450 μm, and the like, or other values, the sum of the thicknesses of the first thermal conductive layer 12 and the second thermal conductive layer 14 in the second section S2 may be greater than 0, and less than or equal to 1nm (0< thickness ≦ 1nm), such as 0.05nm, 0.08nm, 0.1nm, 0.5nm, 0.75nm, or other values, and is not limited. In some embodiments, the sum of the thicknesses of the first and second thermally

conductive layers

12, 14 in the first section S1 can be greater than or equal to 1nm and less than or equal to 1 micrometer (μm) (1 nm. ltoreq. d 1. ltoreq.1 μm), such as 1.5nm, 50nm, 100nm, 400nm, 500nm, 850nm, or 900nm, or the like, or other values, while the sum of the thicknesses of the first and second thermally

conductive layers

12, 14 in the second section S2 can be greater than 0 and less than or equal to 0.1nm (0< d 3. ltoreq.0.1 nm), such as 0.01nm, 0.03nm, 0.05nm, 0.075nm, 0.08nm, 0.09nm, or 0.95nm, or the like, or other values, without limitation.

The reason for adopting the above thickness and its limitation is: during cycling of the working fluid 15 at high and low temperatures, prolonged use can damage and degrade the adhesion of the first and/or second thermally conductive layers 12 and 14 (graphene) materials. Therefore, by providing thicker heat conduction layers (the first heat conduction layer 12 and the second heat conduction layer 14) in the high temperature first section, the degradation of the (graphene) material and the damage of the adhesion thereof can be delayed, thereby increasing the lifetime and the product reliability of the heat conduction structure.

In some embodiments, the thickness of the first thermal conductive layer 12 can be fixed, but the thickness of the second thermal conductive layer 14 can be varied; alternatively, the thickness of the second heat conductive layer 14 is fixed, but the thickness of the first heat conductive layer 12 is varied; still alternatively, the thicknesses of the first and second heat

conductive layers

12 and 14 may be varied at the same time, as long as the sum of the thicknesses of the first and second heat

conductive layers

12 and 14 closer to the heat source side H can be larger than the sum of the thicknesses of the first and second heat

conductive layers

12 and 14 farther from the heat source side H. In addition, fig. 1F is a step-wise variation of the sum of the thicknesses of the first and second thermally

conductive layers

12 and 14 to maximize the sum of the thicknesses adjacent the hot side H and minimize the sum of the thicknesses adjacent the cold side C. However, the sum of the thicknesses of the first thermal conductive layer 12 and the second thermal conductive layer 14 can be gradually changed (from the thickest to the thinnest) in different embodiments, and the application is not limited thereto, as long as the sum of the thicknesses of the first thermal conductive layer 12 and the second thermal conductive layer 14 closer to the thermal source end H can be larger than the sum of the thicknesses of the first thermal conductive layer 12 and the second thermal conductive layer 14 farther from the thermal source end H. In addition, in some embodiments, even if two different heat conduction structures have the above-mentioned thickness sum limitation, if the thickness sum of the first heat conduction layer 12 and the second heat conduction layer 14 of one heat conduction structure is larger, the temperature equalization effect is better, and the protection property for the material is better. The better the temperature equalization effect, the smaller the temperature difference between the heat source end H and the cooling end C is, and the faster the heat energy can be guided from the heat source end H to the cooling end C. It should be noted that the above-mentioned features of thickness and limitations may also be applied in other embodiments of the present invention.

Further, taking fig. 1F as an example, the area where the sum of the thicknesses of the first heat conduction layer 12 and the second heat conduction layer 14 closest to the heat source end H is d1 is the first section S1, and the area where the sum of the thicknesses of the first heat conduction layer 12 and the second heat conduction layer 14 closest to the cooling end C is d3 is the second section S2(d1> d3), wherein the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the first section S1 are at least partially different from the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the second section S2. For example, in the stepped stacked structure S of fig. 1F, the materials of the first and second heat conduction layers 12 and 14 in the first section S1 are, for example, graphene and graphene, respectively, while the materials of the first and second heat conduction layers 12 and 14 in the second section S2 are, for example, graphene and carbon nanotubes, respectively, as long as the materials of any one of the first and second heat conduction layers 12 and 14 in any two sections of the stacked structure S are different, i.e., the condition that the materials of the first and second heat conduction layers 12 and 14 in at least two sections are at least partially different is satisfied. In addition, the first thermal conductive layer 12 and the second thermal conductive layer 14 in at least two sections of the stacked structure have different material characteristics, which can also be applied to other embodiments of the present invention.

The heat conduction structure 1a of fig. 2 is substantially the same as the heat conduction structure 1 of fig. 1B. The main difference from the thermal conduction structure 1 is that the thermal conduction structure 1a of the present embodiment further includes a third thermal conduction layer 16, and the third thermal conduction layer 16 is disposed on a side of the second thermal conduction layer 14 away from the metal microstructure 13. Here, the third heat conductive layer 16 is disposed on the second heat conductive layer 14 such that the third heat conductive layer 16, the second heat conductive layer 14, the metal microstructures 13 and the first heat conductive layer 12 are sequentially stacked on the bottom surface B of the heat conductive unit 11. The third heat conductive layer 16 may be an organic or inorganic material as described above. In some embodiments, the material of the third thermally conductive layer 16 may include, for example, multi-walled carbon nanotubes, aluminum oxide, zinc oxide, titanium oxide, graphene, graphite, or boron nitride, or combinations thereof, or other high thermal conductivity materials. The third heat conductive layer 16 of the present embodiment is exemplified by multi-walled carbon nanotubes. In some embodiments, the third thermal conductive layer 16 can include a plurality of nanotube bodies 161 (e.g., carbon nanotubes), and the axial direction of the nanotube bodies 161 is perpendicular to the surface of the second thermal conductive layer 14. Here, the growth direction of the carbon nanotubes can be controlled by using the process conditions such that the axial direction of the grown carbon nanotubes is perpendicular to the planar direction of the graphene micro-sheet (the second heat conduction layer 14), for example.

In some embodiments, the third thermally conductive layer 16 can cover the surface of the second thermally conductive layer 14 at a coverage rate of 0.001% or more and 100% or less (0.001% to 100% coverage, 100% indicating coverage over all surfaces). In some embodiments, the third thermal conductive layer 16 can cover the surface of the second thermal conductive layer 14 at a coverage rate of 5% or more and 100% or less (5% to 100% coverage), such as 7%, 10%, 12%, 15%, 20%, 25%, 30%, …, or 90%, etc.; in some embodiments, the coverage of the third thermal conductive layer 16 on the surface of the second thermal conductive layer 14 can be greater than or equal to 0.001%, and less than or equal to 5% (0.001% ≦ 5%), such as 0.005%, 0.01%, 0.02%, 0.5%, 1%, …, or 3%, and the like, without limitation. In addition, the above-mentioned feature that the third thermal conductive layer 16 covers at least a portion of the surface of the second thermal conductive layer 14 and the coverage rate thereof can also be applied to other embodiments of the present invention.

In the present embodiment, the third thermal conductive layer 16 (carbon nanotubes) is disposed on the second thermal conductive layer 14, so as to further enhance the speed of the working fluid 15 entering/exiting the second thermal conductive layer 14 and the first thermal conductive layer 12, thereby further increasing the thermal conductive efficiency. In addition to increasing the thermal conduction efficiency, the third thermal conductive layer 16 (carbon nanotubes) of the present embodiment can also increase the coverage of the second thermal conductive layer 14 and the first thermal conductive layer 12 (graphene layer). The increased coverage further increases the hydrophilicity of the second thermally conductive layer 14 and the first thermally conductive layer 12 (graphene material), and also increases the protection of the metal microstructure 13 from corrosion or oxidation. The higher the hydrophilicity, the smaller the contact angle (contact angle), the more easily the working fluid 15 in the closed cavity 111, such as water and water vapor, can be continuously attached to the surface of the graphene/carbon nanotube, so that the water is more easily evaporated and the water vapor is more easily condensed, the cycle efficiency can be increased, and the heat conduction efficiency can be increased.

In addition, the heat conduction structure includes the features of the third heat conduction layer 16, and can also be applied in combination with other embodiments of the present invention, such as stepped or gradually-increasing thickness and variation features, so that the sum of the thicknesses of the first, second and third heat conduction layers 12, 14, 16 adjacent to the heat source end H can be greater than the sum of the thicknesses of the first, second and third heat conduction layers 12, 14, 16 remote from the heat source end H; alternatively, the first, second, and third heat

conductive layers

12, 14, and 16 in the first section S1 of the at least two sections are at least partially different from the first, second, and third heat

conductive layers

12, 14, and 16 in the second section S2.

In addition, please refer to fig. 3A and fig. 3B, which are schematic cross-sectional views of a heat conduction structure according to another embodiment of the present invention.

The heat conduction structure 1B in fig. 3A and 3B is substantially the same as the heat conduction structure 1a in fig. 2. The main difference from the heat conduction structure 1a is that the first heat conduction layer 12 of the heat conduction structure 1B of the present embodiment is disposed on the bottom surface B and the top surface T of the closed cavity 111, respectively. Therefore, as shown in fig. 3A, the bottom surface B and the top surface T of the closed cavity 111 have a mirror structure. Wherein, the bottom surface B has a first heat conduction layer 12, a metal microstructure 13, a second heat conduction layer 14 and a third heat conduction layer 16 from bottom to top, and the top surface T has a third heat conduction layer 16, a second heat conduction layer 14, a metal microstructure 13 and a first heat conduction layer 12 from bottom to top (fig. 3B indicates a stacked structure of the third heat conduction layer 16, the second heat conduction layer 14, the metal microstructure 13 and the first heat conduction layer 12 with reference numbers "S", "S '", respectively, and two third heat conduction layers 16 of the stacked structure S, S' are opposite to each other). Since the bottom surface B and the top surface T of the heat conducting unit 11 are respectively provided with the stacked structures S, S', the condensed liquid working fluid 15 can respectively flow back to the heat source end H (flowing to D2) along the metal microstructures 13 of the bottom surface B and the top surface T, so as to increase the condensed backflow amount of the liquid working fluid 15, and further increase the heat conduction efficiency.

Fig. 3C is a schematic cross-sectional view of a heat conduction structure according to another embodiment of the present invention.

The heat conduction structure 1C of fig. 3C is substantially the same as the heat conduction structure 1B of fig. 3B. The main difference from the heat conduction structure 1b is that the inner side surface of the closed cavity 111 of the heat conduction structure 1c of the present embodiment may further include a fourth heat conduction layer 17 besides the stacked structure S, S ', and the fourth heat conduction layer 17 is disposed at a position without the stacked structure S, S' in the inner side surface of the closed cavity 111. In other words, the fourth thermal conductive layer 17 of the present embodiment is disposed on two opposite sidewalls of the closed cavity 111, and does not overlap with the stacked structure S, S'. Of course, the fourth heat conductive layer 17 may also have a partial overlap with the stacked structure S, S' due to manufacturing tolerances, and is not limited. The fourth thermal conductive layer 17 may be made of the same material as the first thermal conductive layer 12, the second thermal conductive layer 14, or the third thermal conductive layer 16, such as graphene or carbon nanotubes, so as to increase the coverage of the thermal conductive unit 11, make the material (such as copper) of the thermal conductive unit 11 have better hydrophilicity, and further increase the thermal conductive effect, and meanwhile, the fourth thermal conductive layer 17 can improve the protection of the thermal conductive unit 11 to prevent corrosion or oxidation of the thermal conductive unit 11.

In some embodiments, the fourth thermal conductive layer 17 covers at least a portion of the surface of the closed cavity 111 at the two opposite sidewalls not having the stacked structure S, S', and the coverage thereof may be greater than or equal to 0.01% and less than or equal to 100% (0.01% ≦ coverage ≦ 100%). In some embodiments, the coverage of the fourth thermally conductive layer 17 at the positions where there is no stacked structure S, S' in the two opposite sidewalls of the inner side surface of the closed cavity 111 may be equal to or greater than 0.02%, and equal to or less than 5% (0.02% ≦ coverage ≦ 5%), such as 0.05%, 0.5%, 1%, 1.5%, 2%, 3%, or 4.5%, or the like, or other percentages, without limitation.

In various embodiments, if only the bottom surface B has the form of the stacked structure S (for example, fig. 1C), the fourth heat conductive layer 17 can be disposed at a position without the stacked structure S in the inner surface of the closed cavity 111, i.e., disposed on two opposite sidewalls of the inner surface of the closed cavity 111 and the top surface T thereof. In addition, the heat conduction structure including the features of the fourth heat conduction layer 17 can also be applied to other embodiments of the present invention.

In addition, other technical features of the

heat conduction structures

1a, 1b, and 1c can refer to the same components of the heat conduction structure 1, and are not described herein again.

In addition, in the

heat conduction structures

1, 1a, 1b, 1c, in the direction along the X-X secant line (i.e. the long axis direction of the heat conduction unit 11), the stacked structure S (or S, S') can be divided into at least two sections, which can include a first section and a second section, wherein the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the first section are at least partially different from the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the second section; alternatively, the materials of the first, second and third thermally

conductive layers

12, 14, 16 in the first section are at least partially different from the materials of the first, second and third thermally

conductive layers

12, 14, 16 in the second section.

For example, taking fig. 1C as an example, the stacked structure S can be divided into a first section S1 closest to the heat source end H and a second section S2 closest to the cooling end C (which are adjacent to each other), wherein the materials of the first heat conduction layer S1 and the second heat conduction layer 14 in the first section S1 are, for example, graphene and graphene, respectively, while the materials of the first heat conduction layer 12 and the second heat conduction layer 14 in the second section S2 are, for example, graphene and carbon nanotube, respectively; as long as the materials of any one of the materials of the first and second thermally

conductive layers

12, 14 in the two sections are different, the above-mentioned condition that the materials of the first and second thermally

conductive layers

12, 14 in the at least two sections are at least partially different is satisfied.

Further, taking fig. 3B as an example, the stacked structure S, S ' can be divided into a first section S1, S1 ' closest to the heat source end H and a second section S2, S2 ' closest to the cooling end C (which are adjacent to each other), wherein the materials of the first, second, and third heat conduction layers S1, S14, and 16 in the first section S1, S1 ' are graphene, and carbon nanotube, respectively, but the materials of the first, second, and third heat conduction layers 12, S14, and 16 in the second section S2, S2 ' are graphene, and graphene, respectively; alternatively, the materials of the first, second, and third heat conduction layers 12, 14, and 16 in the second sections S2, S2' are, for example, graphene, carbon nanotube, and graphene, respectively, as long as the materials of any one of the materials of the first, second, and third heat conduction layers 12, 14, and 16 in the two sections are different, that is, the condition that the materials of the first, second, and third heat conduction layers 12, 14, and 16 in the at least two sections are at least partially different is satisfied. The above materials are only examples and are not intended to limit the present invention.

Of course, in different embodiments, the stacked structure S or the stacked structure S, S' may also be divided into three or more sections, and the materials of the first, second, and third heat

conductive layers

12, 14, 15 in at least two of the three or more sections are at least partially different. In addition, the first thermal conductive layer 12 and the second thermal conductive layer 14 in at least two sections of the stacked structure have different material characteristics, or the first thermal conductive layer 12, the second thermal conductive layer 14 and the third thermal conductive layer 16 in at least two sections have different material characteristics, which can also be applied to other embodiments of the present invention, including the step-type thermal conductive structure shown in fig. 1F or the asymptotically-varying thermal conductive structure.

Fig. 4 is a schematic diagram of a mobile device according to an embodiment of the invention. As shown in fig. 4, the mobile device 2 of the present embodiment is a mobile phone as an example. The mobile device 2 includes a heat source HS and a heat conduction structure 3, the heat conduction structure 3 is disposed inside the mobile device 2, and one end (i.e. the heat source end) of the heat conduction structure 3 can contact the heat source HS, so as to guide and transfer the heat generated by the heat source to the cooling end, and then dissipate the heat to the outside through, for example, a back cover (not shown) of the mobile device 2. The heat conduction structure 3 may be the

heat conduction structure

1, 1a, 1b, or 1c, or a variation thereof, for which reference is made to the above for specific technical content, which is not described herein again. The heat source in the present embodiment is exemplified by the CPU of the mobile device 2. In some embodiments, the CPU temperature of the mobile device 2 is relatively high, possibly exceeding 100 ℃, and is suitable for conducting and dissipating heat by using the heat conduction structure of the above embodiments of the present invention. In addition, in various embodiments, the heat source may also be a memory chip (card), a display chip (card), a panel, or a power element of the mobile device 2, or other elements, units, or components that generate high-temperature heat energy.

It should be noted that, in an experimental example of the heat conduction structure of the present invention, the working fluid 15 is, for example, water, the heat source temperature is, for example, 65 ℃, the materials of the first heat conduction layer 12 and the second heat conduction layer 14 are, for example, graphene, and the thickness thereof is, for example, between 0.6 nanometers (nm) and 1.5nm, respectively, the material of the third heat conduction layer 16 is, for example, carbon nanotubes, and the thickness thereof is, for example, between 2nm and 3nm, and the metal microstructure 13 is, for example, a copper mesh, and the thickness thereof is, for example, less than 80 micrometers (μm). The temperature difference comparison between the thermal conduction structure of the present embodiment and the well-known isothermal plate (without the first heat conduction layer, the second heat conduction layer, and the third heat conduction layer) can be found in the following table:

as can be seen from the above table, if the well-known temperature equalizing plate (only the copper mesh on the first substrate, without the first heat conductive layer, the second heat conductive layer and the third heat conductive layer) is used, the temperature difference between the heat source end and the cooling end can reach 2.7 ℃, however, in the heat conduction structure according to an embodiment of the present invention, when the lower substrate has a carbon nanotube/graphene/copper mesh/graphene structure, the temperature difference between the hot source end and the cooling end is only 1.5 ℃, and when the lower substrate and the upper substrate both have graphene/copper mesh/graphene/carbon nano tubes, the temperature difference between the heat source end and the cooling end is only 1.2 ℃, and the heat conduction structure provided by the embodiment of the application is proved to have higher heat conduction efficiency and better temperature equalization effect, and the heat conduction structure not only can quickly guide out the heat energy generated by the heat source, but also can meet the heat dissipation requirement of a light and thin mobile device.

In addition, in a long-day comparative experimental example of the present invention, two different heat conduction structures are shared, and are referred to herein as a "first heat conduction structure" and a "second heat conduction structure". Here, "different heat conduction structures" mean that the thicknesses of the first heat conduction layer, the second heat conduction layer, and the third heat conduction layer inside thereof are different, and other conditions (e.g., materials, dimensions) are the same. The first heat conduction layer and the second heat conduction layer are, for example, graphene layers, the third heat conduction layer is, for example, carbon nanotubes, and the metal microstructure is, for example, a copper mesh (with a constant thickness).

In the first heat conduction structure, the sum of the thicknesses of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer is 500 nanometers (nm), 300nm, 50nm and 5nm in sequence from the adjacent heat source end to the different sections far away from the heat source end; in the second heat conduction structure, the thickness of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer is constant, and is 5nm thick from the adjacent heat source end to the far away heat source end. The first heat conduction structure and the second heat conduction structure have the first heat conduction layer, the second heat conduction layer and the third heat conduction layer, so that the temperature difference between the heat source end and the cooling end of the first heat conduction structure and the second heat conduction structure is lower than that of a well-known temperature equalization plate (without the first heat conduction layer, the second heat conduction layer and the third heat conduction layer), and the heat conduction structure provided by the application has higher heat conduction efficiency to ensure better temperature equalization effect.

In addition, after the first heat conduction structure and the second heat conduction structure are simultaneously contacted with a heat source (for example, 150 ℃) and are in heat balance, the temperature of the cooling end of the first heat conduction structure is 149.1 ℃ (the temperature difference between the heat source end and the cooling end is 0.9 ℃), and the temperature of the cooling end of the second heat conduction structure is 147.6 ℃ (the temperature difference between the heat source end and the cooling end is 2.4 ℃); after 30 days, the temperature of the cooling end of the first heat transfer structure was 148.6 ℃ (with a 1.4 ℃ temperature difference) and the temperature of the cooling end of the second heat transfer structure was 146.7 ℃ (with a 3.3 ℃ temperature difference); after 90 days, the temperature of the cooling end of the first heat conduction structure is 147.9 ℃ (the temperature difference is 2.1 ℃), and the temperature of the cooling end of the second heat conduction structure is 145.2 ℃ (the temperature difference is 4.8 ℃).

Two characteristics can be seen from the above, the first one: under the same time, the temperature equalizing effect of the first heat conduction structure is better than that of the second heat conduction structure, and the sum of the thicknesses of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer which are close to the heat source end is proved to be larger than the sum of the thicknesses of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer which are far away from the heat source end, so that the heat conduction structure has better heat conduction efficiency; the second characteristic is that: however, if the sum of the thicknesses of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer adjacent to the heat source end is larger than the sum of the thicknesses of the first heat conduction layer, the second heat conduction layer and the third heat conduction layer away from the heat source end, the deterioration degree of the graphene is smaller, the damage of the material and the adhesiveness thereof can be delayed, the deterioration degree of the heat conduction efficiency is smaller, and the advantage of the graphene can be proved.

Hereinafter, the process of manufacturing the heat conduction structure of the present application will be described. Fig. 5A and 5B are schematic views illustrating different manufacturing processes of the heat conduction structure according to the present invention, fig. 6A to 6E are schematic views illustrating a manufacturing process of the heat conduction structure according to an embodiment of the present invention, and fig. 7A and 7B are partial schematic views illustrating another manufacturing process of the heat conduction structure according to an embodiment of the present invention.

As shown in fig. 5A, the method of manufacturing the heat conduction structure may include steps S01 to S05. Here, step S01 is performed first: a first thermally conductive layer 12 is formed on the first substrate 10a and/or the second substrate 10 b. As shown in fig. 6A, in the present embodiment, the first heat conductive layer 12 (e.g., a graphene layer) is formed on the bottom surface B of the recessed first substrate 10 a. In different embodiments, the first thermal conductive layer 12 can also be formed on the first substrate 10a, or on the first substrate 10a and the second substrate 10b, which are flat, but the invention is not limited thereto. In some embodiments, the first thermal conductive layer 12 may be formed on the first substrate 10a and/or the second substrate 10b by Chemical Vapor Deposition (CVD), spraying, coating, adhering, or other suitable methods. In some embodiments, the first substrate 10a and the second substrate 10b may be semi-cylindrical (both are combined into a heat pipe), and the first heat conductive layer 12 may be formed on the inner surface of the first substrate 10a and/or the second substrate 10b (i.e., the inner surface of the heat pipe has the first heat conductive layer 12).

Subsequently, step S02 is performed: a metal microstructure 13 is formed on the first substrate 10a and/or the second substrate 10b, such that the first heat conduction layer 12 is located between the metal microstructure 13 and the first substrate 10a and/or the second substrate 10 b. As shown in fig. 6B, in the embodiment, a metal microstructure 13 (e.g., a copper mesh) is formed on the first substrate 10a, such that the first heat conductive layer 12 can be located between the metal microstructure 13 and the first substrate 10 a. In some embodiments, the metal microstructure 13 may be disposed on the first substrate 10a and/or the second substrate 10b by, for example, a thermal process, a thermal sintering process, or other suitable methods, such that the first heat conduction layer 12 covers at least a portion of a lower surface of the metal microstructure 13, and the first heat conduction layer 12 is located between the metal microstructure 13 and the first substrate 10a and/or the second substrate 10 b.

Thereafter, step S03 is performed: as shown in fig. 6C, a second thermally conductive layer 14 is formed on the side of the metal microstructure 13 remote from the first thermally conductive layer 12. In some embodiments, the second heat conductive layer 14 (e.g., a graphene layer) can be formed on the metal microstructure 13 by, for example, Chemical Vapor Deposition (CVD), electrical bonding, or adhesive bonding, or other suitable methods, such that the second heat conductive layer 14 covers at least a portion of the upper surface of the metal microstructure 13, and the metal microstructure 13 is located between the second heat conductive layer 14 and the first heat conductive layer 12.

Subsequently, step S04 is performed: as shown in fig. 6D, the first substrate 10a and the second substrate 10b are combined to form the heat conducting unit 11, wherein the heat conducting unit 11 forms the closed cavity 111. Here, the sides of the first substrate 10a and the second substrate 10b may be connected together by, for example, a soldering or an adhesion process to form the heat conducting unit 11 having the closed cavity 111. However, in order to be filled with the working fluid 15, at least one gap O is required to be left on the side of the heat conducting unit 11 (e.g., on the second substrate 10b) so that the working fluid 15 can be injected through the gap O. In some embodiments, the gap O is, for example and without limitation, located at the connection of the sides of the heat conducting unit 11.

Then, step S05 is performed: the working fluid 15 is injected into the closed cavity 111 through the gap O of the heat conducting unit 11, wherein the working fluid 15 includes the carbon material 151 therein. In some embodiments, the working fluid 15 may be injected into the enclosed cavity 111 using, for example, but not limited to, an injection needle extending into the notch O. After that, the gap O is sealed to obtain the heat conduction structure 1 of fig. 6E (the structure is the same as that of fig. 1B).

In some embodiments, before the step S04 of combining the first substrate 10a and the second substrate 10b, the manufacturing method of the present invention may further include the steps of: forming a third heat conduction layer 16 on the side of the second heat conduction layer 14 away from the metal microstructure 13 (refer to the heat conduction structure 1a in fig. 2); then, the above steps S04 and S05 are performed. In some embodiments, the third heat conductive layer 16 can be formed by growing, for example, multi-walled carbon nanotubes on the second conductive layer 14 using, for example, an arc discharge process, a laser vaporization process, or a chemical vapor deposition process. Preferably, the axial direction of the grown carbon nanotubes is perpendicular to the surface of the second heat conductive layer 14.

In some embodiments, before the step S04 of combining the first substrate 10a and the second substrate 10b, the manufacturing method of the present invention may further include the steps of: the fourth heat conductive layer 17 is formed at a position having no stacked structure in the inner side surface of the closed cavity 111.

In addition, as shown in fig. 5B, another method of manufacturing a heat conduction structure according to an embodiment of the present invention may include steps T01 through T05. First, step T01 is performed: as shown in fig. 7A, a first thermally conductive layer 12 is first formed on the metal microstructure 13. Here, the first heat conductive layer 12 may be formed on the lower side of the metal microstructure 13 by, for example, Chemical Vapor Deposition (CVD), electrical bonding, or adhesive bonding, so as to cover at least a portion of the lower surface of the metal microstructure 13. Next, as shown in fig. 7B, step T02 is performed: a second heat conductive layer 14 is formed on a side of the metal microstructure 13 away from the first heat conductive layer 12 to cover at least a portion of an upper surface of the metal microstructure 13, such that the metal microstructure 13 is sandwiched between the second heat conductive layer 14 and the first heat conductive layer 12. In some embodiments, the steps T01 and T02 can be performed simultaneously, that is, the second heat conductive layer 14 and the first heat conductive layer 12 can be formed on the upper surface and the lower surface of the metal microstructure 13 in one process.

Thereafter, step T03 is performed: a metal microstructure 13 having a first heat conduction layer 12 and a second heat conduction layer 14 is disposed on the first substrate 10a and/or the second substrate 10b, such that the first heat conduction layer 12 is located between the metal microstructure 13 and the first substrate 10a and/or the second substrate 10 b. Referring to fig. 6C, the metal microstructure 13 having the first heat conductive layer 12 and the second heat conductive layer 14 is disposed on the bottom surface B of the recessed first substrate 10a, such that the first heat conductive layer 12 is located between the metal microstructure 13 and the first substrate 10 a.

Next, referring to fig. 6D, step T04 is performed: the first substrate 10a and the second substrate 10b are combined to form the heat conducting unit 11, wherein the heat conducting unit 11 forms a closed cavity 111. Then, referring to fig. 6E, step T05 is performed again: the working fluid 15 is injected into the closed cavity 111 through the gap O of the heat conducting unit 11, wherein the working fluid 15 includes the carbon material 151 therein. Then, the gap O is sealed to obtain the heat conduction structure 1.

Likewise, in some embodiments, before the step T04 of combining the first substrate 10a and the second substrate 10b, the manufacturing method of the present invention may further include the steps of: forming a third heat conduction layer 16 on the side of the second heat conduction layer 14 away from the metal microstructure 13 (refer to the heat conduction structure 1a in fig. 2); thereafter, the steps T04 and T05 are also performed. In some embodiments, before the step T04 of combining the first substrate 10a and the second substrate 10b, the manufacturing method of the present invention may further include the steps of: the fourth heat conductive layer 17 is formed at a position having no stacked structure in the inner side surface of the closed cavity 111.

In addition, other technical features of the method for manufacturing the heat conduction structure are described in detail above, and are not described herein again.

Further, in the structure and the process of the above embodiment of the invention, the first heat conduction layer 12 and the second heat conduction layer 14 are specifically formed on two sides of the metal microstructure 13 by two different processes, so that the two sides of the metal microstructure 13 are purposefully covered with the first heat conduction layer 12 and the second heat conduction layer 14 respectively (although the first heat conduction layer 12 and the second heat conduction layer 14 are films generated by different processes, the materials may be the same or different), which is different from the structure obtained by forming a graphene layer on the upper side of the copper microstructure by one process in the well-known process; moreover, when the first heat conductive layer 12 and the second heat conductive layer 14 are correspondingly covered on two sides of the metal microstructure 13, the hydrophilicity of the metal microstructure 13, the circulation efficiency of the working fluid 15, the temperature equalization effect of the heat conductive structure, and the heat conductive effect are better than those of the structure manufactured by the well-known manufacturing process.

In summary, in the heat conduction structure, the manufacturing method thereof and the mobile device of the invention, the first heat conduction layer and the second heat conduction layer are disposed on two sides of the metal microstructure inside the heat conduction structure, and the working fluid including the carbon material is disposed in the closed cavity of the heat conduction unit, so that the hydrophilicity of the metal microstructure can be increased, the reflux rate of the liquid working fluid in the metal microstructure can be increased, the circulation efficiency of the working fluid can be increased, and the temperature equalization effect and the heat conduction effect of the heat conduction structure are better. Therefore, the heat conduction structure of the invention has higher heat conduction efficiency, can quickly conduct out the heat energy generated by the heat source, and is also suitable for the heat dissipation requirement of a light and thin mobile device.

The foregoing is illustrative only and is not limiting. Any equivalent modifications or variations without departing from the spirit and scope of the present invention should be included in the claims of the present application.

Claims

1. A heat conducting structure, comprising:

a heat conducting unit forming a closed cavity having opposing bottom and top surfaces;

a first heat conductive layer disposed on the bottom surface and/or the top surface of the closed cavity;

a metal microstructure disposed on the first heat conductive layer such that the first heat conductive layer is located between the metal microstructure and the bottom surface and/or the top surface;

the second heat conduction layer is arranged on one side, far away from the first heat conduction layer, of the metal microstructure; and

a working fluid disposed within the closed cavity of the heat conducting unit, wherein the working fluid includes a carbon material therein.

2. The heat conducting structure according to claim 1, wherein the first heat conductive layer or the second heat conductive layer covers at least a part of a surface of the metal microstructure.

3. The thermal conduction structure of claim 1, wherein the coverage of the first thermal conductive layer or the second thermal conductive layer on the surface of the metal microstructure is greater than or equal to 5% and less than or equal to 100%.

4. The heat conduction structure of claim 1, wherein the first heat conduction layer, the metal microstructure and the second heat conduction layer form a stacked structure, the stacked structure is divided into at least two sections along a long axis direction of the heat conduction unit, the at least two sections include a first section and a second section, and the first heat conduction layer and the second heat conduction layer in the first section are at least partially different in material from the first heat conduction layer and the second heat conduction layer in the second section.

5. The heat conducting structure of claim 1, wherein a material of the first or second heat conducting layer comprises graphene, graphite, carbon nanotubes, aluminum oxide, zinc oxide, titanium oxide, or boron nitride, or a combination thereof.

6. The heat conducting structure according to claim 1, further comprising:

and the third heat conduction layer is arranged on one side, far away from the metal microstructure, of the second heat conduction layer.

7. The heat conduction structure of claim 6, wherein the first heat conduction layer, the metal microstructure, the second heat conduction layer, and the third heat conduction layer form a stacked structure, the stacked structure is divided into at least two sections along a long axis direction of the heat conduction unit, the at least two sections include a first section and a second section, and the first heat conduction layer, the second heat conduction layer, and the third heat conduction layer in the first section are at least partially different from the first heat conduction layer, the second heat conduction layer, and the third heat conduction layer in the second section.

8. The heat conducting structure according to claim 6, wherein the third heat conductive layer comprises a plurality of nanotubes, an axial direction of the plurality of nanotubes being perpendicular to a surface of the second heat conductive layer.

9. The heat conducting structure according to claim 1, further comprising:

a fourth heat conduction layer disposed in the inner surface of the closed cavity at a position without the first heat conduction layer, the metal microstructure and the second heat conduction layer.

10. The heat conducting structure according to claim 1, wherein the carbon material is graphite, graphene, carbon nanotubes, carbon spheres, or carbon wires, or a combination thereof; the percentage of the carbon material in the working fluid is 0.0001% or more and 2% or less.

11. A mobile device, comprising:

a heat source; and

the heat conducting structure according to any one of claims 1 to 10, wherein one end of the heat conducting structure contacts the heat source.

12. A method of manufacturing a heat conducting structure comprising the steps of:

forming a first heat conductive layer on the first substrate and/or the second substrate;

forming a metal microstructure on the first substrate and/or the second substrate such that the first heat conduction layer is located between the metal microstructure and the first substrate and/or the second substrate;

forming a second heat conduction layer on one side of the metal microstructure far away from the first heat conduction layer;

combining the first substrate and the second substrate to form a heat conducting unit, wherein the heat conducting unit forms a closed cavity; and

injecting a working fluid into the closed cavity through the gap of the heat conducting unit, wherein the working fluid comprises a carbon material.

13. A method of manufacturing a heat conducting structure comprising the steps of:

forming a first heat conduction layer on the metal microstructure;

arranging the metal microstructure with the first heat conduction layer and the second heat conduction layer on a first substrate and/or a second substrate, and enabling the first heat conduction layer to be located between the metal microstructure and the first substrate and/or the second substrate;

14. The manufacturing method according to claim 12 or 13, wherein, before the step of combining the first substrate and the second substrate, it further comprises the steps of:

and forming a third heat conduction layer on one side of the second heat conduction layer far away from the metal microstructure.

15. The manufacturing method according to claim 14, wherein, before the step of combining the first substrate and the second substrate, it further comprises the steps of:

and forming a fourth heat conduction layer at the position without the first heat conduction layer, the metal microstructure, the second heat conduction layer and the third heat conduction layer in the inner surface of the closed cavity.

16. The manufacturing method according to claim 12 or 13, wherein, before the step of combining the first substrate and the second substrate, it further comprises the steps of:

and forming a fourth heat conduction layer in the inner surface of the closed cavity at a position without the first heat conduction layer, the metal microstructure and the second heat conduction layer.

17. The production method according to claim 12 or 13, wherein the carbon material is graphite, graphene, a carbon nanotube, a carbon sphere, or a carbon wire, or a combination thereof; the percentage of the carbon material in the working fluid is 0.0001% or more and 2% or less.