CN108738284B - A graphene composite heat dissipation laminate structure and manufacturing method thereof - Google Patents

Abstract

The invention discloses a heat dissipation lamination structure which comprises at least two composite heat dissipation layers which are sequentially overlapped, wherein each composite heat dissipation layer comprises a back adhesive layer (11), a metal foil layer (12) and a nonmetal layer (13) which are sequentially overlapped. Preferably, the invention further comprises a liquid metal layer (14) formed between the metal foil layer (12) and the nonmetal layer (13), wherein a sunken groove or pit is formed on the surface of the metal foil layer (12) facing the nonmetal layer (13), and a capillary structure can be formed at the bottom and the side of the pit or the groove. The invention can obviously improve the heat radiation efficiency of the radiator and reduce the damage of heat to peripheral devices.

Description

A graphene composite heat dissipation laminate structure and manufacturing method thereof

Technical Field

The invention belongs to the field of heat dissipation technology, and in particular relates to a heat dissipation technology using graphene.

Background technique

Conventional heat dissipation materials include silicone, high thermal conductivity metals, etc. Among metals, copper and aluminum are particularly commonly used. The thermal conductivity of copper is 398W/mK, but it has disadvantages such as high density and easy oxidation. The thermal conductivity of aluminum is not high (237W/mK), and sometimes it is difficult to meet the needs of existing products for thermal conductivity and heat dissipation. The heat dissipation films made of natural graphite materials and synthetic graphite materials currently in use have improved the heat dissipation of electronic products to a certain extent, but graphite heat dissipation films are mainly made by directly calendering graphite after processing, as well as by polymer carbonization, graphitization and other methods. The heat dissipation materials with graphite on the surface have low tensile strength, are fragile, and have a lot of particle dust, which is inconvenient to install and use.

Graphene is a two-dimensional material with a thickness of only one carbon atom and a planar film composed of carbon atoms in a hexagonal honeycomb lattice with ^sp2 hybrid orbitals. Graphene is the thinnest but also the hardest nanomaterial in the world, with a thermal conductivity of up to 5300W/m·K, higher than carbon nanotubes and diamonds, which makes graphene a new star in the field of heat dissipation materials. However, the thermal conductivity of graphene is anisotropic, and its heat dissipation effect is better only in the two-dimensional plane, while its thermal conductivity in the longitudinal direction is sharply discounted, and the existing graphene heat dissipation films have not solved this problem. In addition, the graphene heat dissipation films prepared by the existing process are all one-layer heat dissipation structures, and the heat dissipation efficiency needs to be further improved.

Summary of the invention

1. Technical issues to be resolved

The present invention aims to solve the shortcomings of the existing heat dissipation structure, such as low heat dissipation efficiency and damage to peripheral devices caused by heat.

(II) Technical solution

To solve the above technical problems, the present invention proposes a heat dissipation laminate structure, comprising at least two composite heat dissipation layers stacked in sequence, each composite heat dissipation layer comprising a backing adhesive layer, a metal foil layer and a non-metallic layer stacked in sequence.

According to a preferred embodiment of the present invention, a protective layer is further included, and the protective layer is coated on the outside of each composite heat dissipation layer.

According to a preferred embodiment of the present invention, the non-metallic layer is a graphene-based material.

According to a preferred embodiment of the present invention, the invention further comprises a liquid metal layer formed between the metal foil layer and the non-metal layer.

According to a preferred embodiment of the present invention, the melting point of the liquid metal layer is between 40 degrees and 150 degrees, and the thickness is between 1 μm and 30 μm.

According to a preferred embodiment of the present invention, the liquid metal layer is embedded in the surface of the metal foil layer facing the non-metal layer and is flush with the surface.

According to a preferred embodiment of the present invention, the liquid metal layer is embedded in the surface of the metal foil layer facing the non-metal layer and is sunken into the surface.

According to a preferred embodiment of the present invention, sunken grooves or pits are provided on the surface of the metal foil layer facing the non-metallic layer, and the grooves or pits are regularly arranged in a plane direction perpendicular to the heat conduction direction.

According to a preferred embodiment of the present invention, a sunken groove or pit is provided on the surface of the metal foil layer facing the non-metallic layer, and a capillary structure is formed at the bottom and side of the pit or groove.

The invention also provides a method for manufacturing a heat dissipation laminate structure and a corresponding heat sink.

(III) Beneficial effects

The present invention can significantly improve the heat dissipation efficiency of the radiator and reduce the damage of heat to peripheral devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a first embodiment of a heat dissipation laminate structure of the present invention;

FIG2 is a schematic structural diagram of a second embodiment of a heat dissipation laminate structure of the present invention;

3 is a schematic structural diagram of a third embodiment of the heat dissipation laminate structure of the present invention;

FIG4 is a schematic structural diagram of a fourth embodiment of a heat dissipation laminate structure of the present invention;

5 is a schematic structural diagram of a fifth embodiment of the heat dissipation laminate structure of the present invention;

6 is a schematic structural diagram of a sixth embodiment of the heat dissipation laminate structure of the present invention;

7 is a schematic structural diagram of a seventh embodiment of the heat dissipation laminate structure of the present invention;

FIG. 8 is a schematic structural diagram of an eighth embodiment of the heat dissipation laminate structure of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

FIG1 is a schematic diagram of the structure of the first embodiment of the heat dissipation laminate structure of the present invention. As shown in FIG1 , the heat dissipation laminate structure of the present invention includes a backing adhesive layer 11, a metal foil layer 12 and a non-metallic layer 13 from bottom to top (the direction shown in the figure, there is no restriction on the direction of stacking in actual application). Among them, the backing adhesive layer 11 can adopt a thermal conductive adhesive with a high thermal conductivity, such as silica gel. The metal foil layer 12 can adopt various metals that are solid at room temperature, including copper, aluminum, tin, etc. In the present invention, the non-metallic layer 13 is preferably made of graphene materials, although carbon nanotube films, graphite fibers, etc. can also be used.

According to a preferred embodiment of the present invention, the heat dissipation laminate structure of this embodiment may also be coated with a protective layer (not shown in the figure) on the outermost layer, which may be a metal foil layer or a PET layer, or a composite protective layer composed of a metal foil layer and a PET layer, and the metal foil layer is, for example, an aluminum foil layer.

According to the present invention, the thickness of the adhesive layer 11 is preferably 5 μm to 80 μm, the thickness of the metal foil layer 12 is between 10 μm and 100 μm, and the thickness of the non-metallic layer 13 is between 5 μm and 80 μm.

When preparing the above heat dissipation laminated structure, a backing adhesive layer 11 can be applied on a substrate by coating, spraying, etc., and then a metal foil layer 12 is attached to the backing adhesive layer. Finally, a non-metallic layer 13 is coated on the metal foil layer.

FIG2 is a schematic diagram of the structure of the second embodiment of the heat dissipation laminate structure of the present invention. As shown in FIG2, the heat dissipation laminate structure of this embodiment is a composite structure, that is, the adhesive layer 11, the metal foil layer 12 and the non-metallic layer 13 of the first embodiment are used as a composite heat dissipation layer. Therefore, the composite heat dissipation laminate of the embodiment includes a first composite heat dissipation layer 1 and a second composite heat dissipation layer 2. The adhesive layer of the second composite heat dissipation layer 2 is stacked on the non-metallic layer of the first composite heat dissipation layer 1.

The steps of preparing the above heat dissipation laminate are similar to those of the first embodiment, except that the previous steps are repeated after the first composite heat dissipation layer is completed.

Compared with the first embodiment, the heat dissipation stack structure of the second embodiment has an increased number of layers, so that the distance between the bottom layer that receives heat (the bottom end of the heat dissipation stack structure) and the air interface for heat dissipation (the top end of the heat dissipation stack structure) is increased, which is beneficial for heat to be quickly transferred away from the heat-generating device. While improving the heat dissipation efficiency, it is also beneficial to protect the devices around the heat-generating device.

It should be noted that the metal foil layers of the first composite heat dissipation layer 1 and the second composite heat dissipation layer 2 can be the same or different. For example, the metal foil layer of the first composite heat dissipation layer 1 is copper foil, and the metal foil layer of the second composite heat dissipation layer 2 is aluminum foil.

FIG3 is a schematic diagram of the structure of the third embodiment of the heat dissipation laminate structure of the present invention. As shown in FIG3, this embodiment is a further extension of the second embodiment. The heat dissipation laminate structure includes more than two composite heat dissipation layers, namely, a first composite heat dissipation layer 1, a second composite heat dissipation layer 2, ..., an Nth composite heat dissipation layer n. N is a natural number and is not less than 2.

The method for preparing the heat dissipation stacked structure of this embodiment can also be repeated with reference to the second embodiment, so it will not be described again.

By applying multiple composite heat dissipation layers, the thickness of the heat dissipation laminate structure can be greatly increased, which can effectively and quickly transfer heat to places far away from the heat-generating devices, greatly improving the heat dissipation efficiency and minimizing the damage of heat to surrounding devices.

Fig. 4 is a schematic structural diagram of a fourth embodiment of the heat dissipation laminate structure of the present invention. This embodiment is different from the third embodiment in that the metal foil layers used in adjacent composite heat dissipation layers are made of different metals.

It can be seen from the third and fourth embodiments that the metal foil layers in each composite heat dissipation layer of the multi-composite heat dissipation layer of the present invention can be the same or different. Selecting different metal foil layers can make the change of the temperature gradient in the entire heat dissipation path special, so that targeted design can be carried out according to the needs of different devices to achieve a balance between heat dissipation efficiency and the degree to which heat does not damage surrounding devices.

FIG5 is a schematic diagram of the structure of the fifth embodiment of the heat dissipation laminate structure of the present invention. As shown in FIG5, in order to further reduce the problem of high thermal resistivity between the metal foil layer 12 and the non-metal layer 13 due to process or material compatibility, this embodiment adds a liquid metal layer 14 between the metal foil layer 12 and the non-metal layer 13. The so-called liquid metal here refers to a metal or alloy that is liquid at a temperature slightly higher than room temperature, including a gallium-based binary alloy, a gallium-based multi-element alloy, an indium-based alloy or a bismuth-based alloy. For example, gallium-indium alloy, gallium-lead alloy, gallium-indium-tin alloy, indium-bismuth-copper alloy, etc. Since the liquid metal layer 14 has good compatibility with both the metal foil layer 12 and the non-metal layer 13 after melting (melting point is between 40 degrees and 150 degrees), it can be in close contact with both, reducing thermal resistance and improving heat dissipation efficiency.

The liquid metal layer 14 of this embodiment can be formed by electroplating, powder spraying, deposition, etc. after forming the metal foil layer 12 structure, and then non-metallic materials such as graphene are sprayed on the liquid metal layer 14. The thickness of the liquid metal layer 14 can be 1 μm to 30 μm.

It should be noted that the fifth embodiment of the present invention can also be expanded to a structure of two composite heat dissipation layers or multiple composite heat dissipation layers, that is, it can be applied to the second to fourth embodiments as a new implementation method.

FIG6 is a schematic diagram of the structure of the sixth embodiment of the heat dissipation laminate structure of the present invention. Different from the fifth embodiment, the liquid metal layer 14 of this embodiment is embedded in the surface of the metal foil layer 12 facing the non-metallic layer 13 and is flush with the surface. As shown in FIG6 , it can be considered that a sunken groove or pit is provided on the surface of the metal foil layer 12 facing the non-metallic layer 13. The liquid metal layer 14 fills the groove or pit. The grooves or pits may be regularly arranged in a planar direction perpendicular to the direction of heat conduction, or may be irregularly arranged, and the present invention does not limit this. However, in order to uniformly conduct heat in all directions, the present invention preferably arranges them regularly.

The metal foil layer 12 embedded with the liquid metal layer 14 may be prepared in advance by pressing or the like, or the liquid metal layer 14 may be formed on the metal foil layer 12 by electroplating, spraying or the like.

The advantage of the sixth embodiment over the fifth embodiment is that the liquid metal layer 14 is confined inside the heat dissipation structure and is not likely to flow out and cause damage to the device.

Fig. 7 is a schematic diagram of the structure of the seventh embodiment of the heat dissipation laminate structure of the present invention. Different from the sixth embodiment, the liquid metal layer 14 embedded in the metal foil layer 12 is not flush with the surface of the metal foil layer 12 facing the non-metallic layer 13, but is recessed into the surface of the metal foil layer 12 facing the non-metallic layer 13. Compared with the sixth embodiment, this embodiment can use a smaller amount of liquid metal, reduce the cost of materials, and the liquid metal layer 14 is less likely to flow out or seep out, and is safer.

FIG8 is a schematic diagram of the structure of the eighth embodiment of the heat dissipation laminate structure of the present invention. This embodiment is similar to the sixth and seventh embodiments, but does not have a liquid metal layer 14. Specifically, this embodiment also provides a sunken groove or pit on the surface of the metal foil layer 12 facing the non-metallic layer 13, and a capillary structure is formed at the bottom and side of the pit or groove. The capillary structure may be formed by embossing. By forming the capillary structure, the non-metallic material, such as graphene, can have a larger contact surface after being sprayed onto the metal foil layer 12, and the contact between the two materials is also more dense, thereby effectively improving the thermal conductivity.

The heat dissipation laminated structure of the present invention can be applied to a variety of heat sinks, and all heat sinks adopting the heat dissipation laminated structure of the present invention are within the protection scope of the present invention.

The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims (9)

1. A heat dissipating laminate structure, comprising:

At least two composite heat dissipation layers stacked in sequence;

Each composite heat dissipation layer comprises: a back adhesive layer (11), a metal foil layer (12) and a nonmetal layer (13) which comprises graphene materials are sequentially overlapped; and a liquid metal layer (14) having a melting point of 40-150 ℃ and a thickness of 1-30 [ mu ] m and having good compatibility with both the metal foil layer (12) and the nonmetal layer (13), wherein the liquid metal layer (14) is formed by electroplating, powder spraying and deposition after the metal foil layer (12) structure is formed, and then a nonmetal material is sprayed on the liquid metal layer (14) to form the nonmetal layer (13); the liquid metal layer (14) is embedded on and flush with the surface of the metal foil layer (12) facing the non-metal layer (13), or the liquid metal layer (14) is embedded on and embedded in the surface of the metal foil layer (12) facing the non-metal layer (13);

Wherein, the back glue layer of one compound heat dissipation layer of two adjacent compound heat dissipation layers in at least two compound heat dissipation layers which are overlapped in turn is overlapped on the nonmetallic layer (13) of the other compound heat dissipation layer;

wherein the metal foil layers (12) of adjacent two of the at least two composite heat dissipation layers are of different metals.

2. The heat dissipating laminate structure of claim 1, further comprising a protective layer that is wrapped around the exterior of each of the composite heat dissipating layers.

3. The heat dissipating laminate structure of claim 1, wherein the graphene-based material employs: carbon nanotube film, graphite fiber.

4. A heat dissipating laminate structure as claimed in any one of claims 1 to 3, wherein the liquid metal is an alloy.

5. The heat dissipating laminate structure of claim 4, wherein the liquid metal is a gallium-based binary alloy, a gallium-based multiple alloy, an indium-based alloy, or a bismuth-based alloy.

6. A heat dissipating laminate structure according to any one of claims 1 to 3, characterized in that the surface of the metal foil layer (12) facing the non-metal layer (13) is provided with depressed grooves or pits, which grooves or pits are regularly arranged in a plane direction perpendicular to the heat transfer direction.

7. A heat dissipating laminate structure according to any of claims 1-3, characterized in that the surface of the metal foil layer (12) facing the non-metal layer (13) is provided with depressed grooves or pits and that capillary structures are formed by embossing at the bottom and sides of the pits or grooves.

8. A method of manufacturing a heat dissipating laminate structure, characterized in that the heat dissipating laminate structure is a heat dissipating laminate structure according to any one of claims 1 to 7, and that, in the preparation, at least two composite heat dissipating layers are laminated on a non-metallic layer of one composite heat dissipating layer by a backing layer of the other composite heat dissipating layer, and the previous process is continued.

9. A heat sink comprising the heat dissipating laminate structure of any one of claims 1 to 7.