Multi-layer graphene heat-conducting sheet with strong binding force and rebound resilience

Abstract

The utility model discloses a multi-layer graphene heat-conducting sheet with strong binding force and rebound resilience, which comprises a plurality of graphene films which are punched by a laser and irradiated by an ultraviolet lamp for 1-2 minutes; coating the surface of the first graphene film with a first silica gel layer; placing a second graphene film on the first silica gel layer; enabling a part of the first silica gel layer to permeate into the holes of the first graphene film and the second graphene film; repeating the stacking to form a transverse graphene film and silica gel composite material block; cutting along the direction of the stacking thickness to form a plurality of stacked slices; the upper end face and the lower end face are subjected to degumming operation, graphene fiber filling operation is carried out after a hollow part is formed, all the graphene films can be connected with one another, and the multi-layer graphene heat-conducting sheet is high in binding force and rebound resilience. Therefore, the graphene has good bonding performance, can bear high compression rate without cracking, and fundamentally solves the cracking problem of the conventional graphene heat-conducting sheet.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of graphene heat-conducting sheet, especially a vertical multi-layer graphene heat-conducting sheet with high thermal conductivity, low contact thermal resistance, high compression, high and low temperature resistance and other characteristics of strong bonding force and resilience. BACKGROUND

[0002] In recent years, due to the rapid development of high-power central processing units (CPUs), graphics processing units (GPUs), and other semiconductor components, electronic devices are becoming thinner and more powerful. As the density of electronic components (such as chips, integrated circuits, transistors, etc.) increases and the frequency increases, over-heating can occur in certain areas after prolonged use. Typically, the chip in an electronic device is the main heat source when it is working. Not only is heat dissipation necessary to reduce the temperature of the chip itself to ensure its normal operation within the required temperature range, but it must also take into account that heat dissipation should not cause local overheating of the shell, which can cause poor user experience. Previous heat dissipation methods for electronic devices mainly used simple methods such as opening holes, heat conduction, and heat convection. However, these methods cannot meet the heat dissipation needs of high-performance chips, resulting in overheating, uneven heat distribution, reduced heat dissipation efficiency inside the electronic device, and even system command frequency reduction or slow shutdown.

[0003] As Figures 1A-1C shown, a general electronic device 10 mainly includes an electronic component 12 disposed on a circuit board 11, a heat sink 13, and a "heat transfer sheet" or "heat-conducting sheet" 20 disposed between the electronic component 12 and the heat sink 13, which is used to transfer heat generated by the electronic component 12. The commonly used "heat-conducting sheet" 20 in the industry is a heat-conducting silicone sheet. Traditional heat-conducting silicone sheets on the market are generally made of silicone oil, heat-conducting powder, and other additives. The heat-conducting effect relies on the heat-conducting powder in the formula, which is usually aluminum oxide or aluminum nitride. Because it is a powder, the particles cannot completely contact each other, resulting in high thermal resistance. The thermal conductivity coefficient is generally limited to 6-10 W / mK, and it is very difficult to obtain a silicone sheet with higher thermal conductivity, which is also very expensive. Furthermore, as shown in FIG. 2, when the thickness (t1) of the heat-conducting silicone sheet 20A is thick, the thermal resistance increases, and the thermal conductivity coefficient is limited.

[0004] As Figure 1CAs shown, when the thickness (t2) of the set heat-conductive silicone sheet 20B is thin, the heat dissipation effect is limited, and when the thickness of the heat-conductive silicone sheet 20B is too thin, it cannot effectively fill the gap between the electronic component and the heat sink, and the interface thermal resistance performance is limited. With the development of science and technology, the requirements for the heat-conductive silicone sheet are getting higher and higher, and the current heat-conductive silicone sheet cannot meet the existing demand. Therefore, it is necessary to develop a heat-conductive sheet that can greatly improve the thermal conductivity.

[0005] Another "heat-conductive sheet" commonly used in the industry is composed of high-thermal-conductivity materials such as copper, aluminum, and graphite, i.e. heat-conductive copper foil, heat-conductive aluminum foil, or heat-conductive graphite sheet. The advantage of this heat-conductive sheet is that it has good thermal conductivity, but the disadvantage is that high-thermal-conductivity materials such as copper, aluminum, and graphite are not as soft and elastic as heat-conductive silicone sheets, so in actual application, it is difficult to deform along the surface of the electronic component 12 and the heat sink 13, and thus cannot effectively adhere to the gap between the electronic component 12 and the heat sink 13, reducing the interface thermal resistance performance. More importantly, the "heat-conductive sheet" is a rigid material and does not have softness and elasticity, so it is easy to damage the semiconductor chip during the clamping process of the electronic device 10. Therefore, both the traditional heat-conductive silicone sheet and the heat-conductive sheet composed of high-thermal-conductivity materials such as copper, aluminum, and graphite have their own shortcomings.

[0006] As shown in Figure 2A and Figure 2B Graphene is a man-made nanomaterial with high thermal conductivity, which is derived from the hexagonal structure of carbon atoms 31. This structure allows electrons to flow freely between carbon atoms. In one publication, graphene heat-conductive film is immersed in epoxy resin, and after taking out and laminating, it is cut into graphene heat-conductive film / epoxy resin composite material with longitudinal arrangement of graphene heat-conductive film, and its longitudinal thermal conductivity is as high as 384.9 W / (m·K)~1000 W / (m·K) or more. However, the graphene heat-conductive film / epoxy resin composite material obtained by this method is a hard material, which cannot fully contact the interface and has a large thermal resistance, and is not suitable for use as a heat-conductive interface material.

[0007] In addition, in the prior art, graphene is generally made into a heat-conducting sheet powder, which is highly arranged along the longitudinal direction to form a longitudinally high heat-conducting sheet, such as patents disclosed in CN113337253A, CN113560146A, CN113789590A, and the like. This type of patent is to make graphene into a powder, so it does not have a continuous structure, so that the heat conduction resistance between the powders inside the heat-conducting sheet is large, and the heat conduction performance is relatively low. The thermal conductivity of graphene powder is generally above 900 W / (mK), and if the heat conductivity, thermal resistance, compressibility, and compression resilience of the heat-conducting sheet are simultaneously satisfied, the filling amount is difficult to exceed 50 wt.% or more, and the heat-conducting sheet formed thereby is generally not more than 25 W / (mK). If the filling amount is continuously increased to improve the heat conduction performance, it will cause overhardness and cracking.

[0008] Furthermore, in the prior art, graphene heat-conducting films are directly stacked layer by layer to arrange them along the longitudinal direction to obtain a graphene fiber-reinforced heat-conducting sheet with high longitudinal heat conduction. This type of example is disclosed in patents CN113290958A, CN113183544A, and the like.

[0009] This type of patent forms a continuous structure of graphene, but due to the barrier of the graphene heat-conducting film, it is difficult for the high molecular polymer between the layers to form a connection, and the graphene heat-conducting film itself is prone to delamination, causing the formed heat-conducting sheet to be prone to cracking. Although through holes can be provided on the graphene heat-conducting film, they can only increase some connection points and cannot form a complete continuous structure between the high molecules, and cannot fundamentally solve the cracking problem of the obtained heat-conducting sheet.

[0010] CN113556925A discloses a heat-conducting gasket comprising reinforcing fibers, heat-conducting films, and a bonding agent, wherein the reinforcing fibers are inserted side by side into the heat-conducting films to form a stable wave-shaped structure, and the bonding agent is filled into the gaps in the wave-shaped structure to form a tightly combined heat-conducting gasket. The heat-conducting gasket has good heat conduction performance and compression resilience in the longitudinal direction. In addition, CN110491845A also discloses a graphene heat-conducting film that is changed from a planar direction to a longitudinal arrangement through crimping, and then coated with an adhesive to form an integral structure. This type of patent has a graphite-like structure inside the graphene heat-conducting film, which is prone to delamination, not only affecting the overall mechanical stability, but also having the risk of cracking.

[0011] Shenzhen Hongfucheng New Material Co., Ltd. has disclosed several methods for preparing graphene heat-conducting gaskets, one of which is CN114181639A, a method for preparing a self-adhesive graphene heat-conducting gasket, as shown in Figure 3A and 3BAs shown, characterized by comprising the following steps: S1. A layer of adhesive (82) is coated on the first layer of graphene film (81), then the second layer of graphene film (81) is placed on the first layer of graphene film (81), and a layer of adhesive (82) is continuously coated on the second layer of graphene film (81) and the third layer of graphene film (11) is stacked, which is repeated alternately until the target height, and the graphene film block (83) is obtained after the adhesive is cured; S2. A through hole (84) is formed on the graphene film block (83), which penetrates through both sides of the graphene film block (83) and is along the stacking direction of the graphene film; S3. The through hole (84) is filled with a thermally conductive filler, and the graphene-thermally conductive filler three-dimensional structure is formed after the thermally conductive filler is fixed in the through hole (84); S4. The graphene-thermally conductive filler three-dimensional structure is sliced along the stacking direction of the graphene film to obtain a specified thickness of the thermally conductive layer (80); S5. The adhesive is coated on both sides of the graphene thermally conductive gasket along the thickness direction, and the adhesive layer (90) is formed after the adhesive is cured, and the final self-adhesive self-adhesive graphene thermally conductive gasket is obtained.

[0012] Among them, the second is CN 114213986 A, which specifically discloses a kind of thermally conductive insulating graphene gasket and its preparation method.A kind of thermally conductive insulating graphene gasket includes the graphene block of multilayer graphene film, the carbon fiber silk fixed in the graphene block, the carbon fiber silk is arranged along the thickness direction of the graphene block, and forms the graphene-carbon fiber three-dimensional heat conduction structure; Along the horizontal direction of the graphene block, the insulating layer is fixedly connected, and the insulating layer contains anisotropic boron nitride.

[0013] Among them, the third is CN 215527717 U, which provides a kind of graphene thermally conductive gasket, as Figure 4 As shown, it includes: multilayer graphene film (91) stacked in turn, adjacent two graphene film (91) layer is provided with adhesive layer (92), and adjacent two layers of graphene film (91) are connected by the adhesive layer (92); The through hole is formed in the graphene film (91) along the stacking direction, and the carbon fiber silk (93) is fixed in the through hole.

[0014] The above-mentioned published application of Shenzhen Hongfucheng New Material Co., Ltd. coats an adhesive on a multilayer graphene film, then repeatedly stacks until the target height, and obtains a graphene film block after the adhesive is cured; but because the structure of the graphene film is in a loose state, the bonding force is not enough, and it is easy to separate. Therefore, in the prior art CN 114181639A, through holes are formed in the graphene film block, and then a heat-conducting filler is filled in the through holes to form a graphene-heat-conducting filler three-dimensional structure. In the prior art CN 215527717U, carbon fiber filaments are arranged in the graphene block. In the prior art CN 215527717U, through holes are formed in the graphene film along the stacking direction, and carbon fiber filaments are arranged in the through holes.

[0015] Although the above-mentioned prior art uses through holes formed in the graphene film block, and then uses a heat-conducting filler or carbon fiber filaments to increase the bonding force. However, such a design has two problems: first, after the graphene film block (83) is cured, through holes (84) are formed, and then a heat-conducting filler or carbon fiber filaments is filled in the through holes (84), because the aperture of the through holes (84) is very small, only 0.1-0.5 mm, which is difficult to manufacture. Second, the graphene film block (83) is cut along the stacking direction of the graphene film (81) to obtain a specified thickness of the heat-conducting layer (1), which has been cured and has lost the original elasticity of the graphene, becoming incompressible.

[0016] From the above prior art analysis, from the application requirements of the heat-conducting sheet, how to obtain high heat-conducting performance in the longitudinal direction and ensure the stability of the structure of the heat-conducting sheet when it is compressed and rebounds is an important issue. Therefore, the present inventors have identified the above-mentioned problems, and further proposed a solution to the shortcomings of the commonly used heat-conducting sheet in the industry. Practical new type content

[0017] The purpose of the present application is to provide a multi-layer graphene heat-conducting sheet with strong bonding force and elasticity, which is a vertical multi-layer graphene heat-conducting sheet with strong bonding force and elasticity. The product has high heat-conducting rate, low contact thermal resistance, high compression, high and low temperature resistance, and other characteristics, effectively fills the gap between the heating end and the cooling end, realizes efficient heat transfer between the heating component and the heat dissipation component, and simultaneously plays the role of shock absorption and anti-collision.

[0018] To achieve the above-mentioned purpose, the technical scheme of the multi-layer graphene heat-conducting sheet with strong bonding force and elasticity is as follows:

[0019] Step S01: providing a plurality of graphene films, and performing punching on each graphene film by a laser to form a plurality of holes with a diameter of 0.1 mm to 1 mm, wherein the diameter and the surface area of the holes are determined according to the required bonding force and resilience of the graphene film;

[0020] Step S02: irradiating the punched graphene film with a UV lamp for 1 to 2 minutes to generate hydrophilic functional groups on the surface of the graphene film;

[0021] Step S03: coating a first silica gel layer on the surface of a first graphene film;

[0022] Step S04: placing a second graphene film on the first silica gel layer;

[0023] Step S05: allowing a part of the first silica gel layer to penetrate into the holes of the first graphene film and the second graphene film;

[0024] Step S06: coating a second silica gel layer on the surface of the second graphene film; repeating the above steps S04 and S05 to obtain a graphene film and silica gel layer stack;

[0025] Step S07: curing the graphene film and silica gel layer stack to form a graphene film and silica gel composite block;

[0026] Step S08: vertically cutting the graphene film and silica gel composite block along the stacking direction at an interval of 0.15 mm to 5 mm to form a plurality of stacked slices;

[0027] Step S09: turning the stacked slices by 90 degrees to lie flat;

[0028] Step S10: removing the silica gel from the upper and lower end surfaces of the stacked slices to form a hollow part;

[0029] Step S11: performing graphene fiber filling operation at the hollow part to connect the graphene films to each other, thereby forming a vertical multi-layer graphene heat conduction sheet with a thickness of 0.15 mm to 5 mm, strong bonding force and resilience.

[0030] Further, in the step S01, the thickness of the graphene film is 10 μm to 100 μm, the length is 5 cm to 30 cm or in the form of a roll, and the width is 5 cm to 30 cm; the coating thickness of the silica gel is 0.01 mm to 0.1 mm, the length is 5 cm to 30 cm, and the width is 5 cm to 30 cm.

[0031] Further, in the step S06, the thickness of the graphene film and silica gel layer stack is 5 cm to 30 cm.

[0032] Further, in the step S10, the stack slice is subjected to a silica gel removal operation, and the method includes removing the silica gel from the upper and lower end surfaces by laser (laser) or by solvent.

[0033] Further, in the step S11, the graphene fiber filling operation at the hollow part is performed, and the method includes grinding or ultrasonic processing the surface of the stack slice to form a plurality of graphene fibers in the hollow part.

[0034] The multilayer graphene heat conduction sheet with strong bonding force and resilience is prepared by the following steps: a plurality of graphene films and silica gels are provided, a plurality of holes with a diameter of 0.1 mm to 1 m are formed in each graphene film, and a hydrophilic functional group is generated on the surface of the graphene film; a first silica gel layer is coated on the surface of a first graphene film, and a second graphene film is placed on the first silica gel layer; a part of the first silica gel layer penetrates into the holes of the first graphene film and the second graphene film; then, a second silica gel layer is coated on the surface of the second graphene film, and the above-mentioned graphene film and silica gel layer stacking is repeated to obtain a horizontal graphene film and silica gel layer stack; the horizontal graphene film and silica gel layer stack is solidified to form a horizontal graphene film and silica gel composite block; the horizontal graphene film and silica gel composite block is vertically cut along the stacking direction at an interval of 0.15 mm to 5 mm to form a plurality of stack slices; the stack slices are turned over by 90 degrees and laid flat; the upper and lower end surfaces of the stack slices are subjected to a silica gel removal operation to form a hollow part; and graphene fibers are filled in the hollow part to connect the graphene films between the stack slices, so as to form a vertical multilayer graphene heat conduction sheet with a thickness of 0.15 mm to 5 mm, strong bonding force and resilience.

[0035] With the help of the above technical means, the vertical multi-layer graphene heat conduction sheet with strong bonding force and resilience prepared by the utility model has the following breakthroughs: first, the vertical multi-layer graphene heat conduction sheet prepared by the utility model is first perforated on each graphene film by a laser at the beginning of the process, so that silica gel in the process can penetrate into each hole, so that a plurality of holes are formed, the graphene films can be connected to each other, and a complete continuous structure is formed between the high molecules. Not only good combination, high orientation, and the graphene fiber in the multi-layer graphene heat conduction sheet, when compressed and rebounded, can keep pace with the high molecular polymer, can withstand high compression rate without cracking, and fundamentally solves the cracking problem of the conventional graphene heat conduction sheet. Second, the vertical multi-layer graphene heat conduction sheet prepared by the utility model removes the silica gel at the upper and lower ends between the graphene films, only retains the connecting surface of the middle part, and the graphene fiber is inside the hollow part of the upper and lower ends. Therefore, the vertical multi-layer graphene heat conduction sheet has the characteristics of softness and elasticity, and can avoid damaging electronic elements (semiconductor chips) during the buckling process of operating electronic equipment. Third, the vertical multi-layer graphene heat conduction sheet prepared by the utility model has uniform distribution of graphene fibers between the graphene films, consistent heat conduction, and can conduct heat along the longitudinal direction, thereby avoiding heat accumulation caused by heat conduction along the transverse direction. Therefore, the product has the characteristics of high thermal conductivity, low contact thermal resistance, high compression, high and low temperature resistance, etc., effectively fills the gap between the heating end and the cooling end, realizes efficient heat transfer between the heating part and the heat dissipation part, and plays a shock absorbing and anti-collision role. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1A A conventional electronic equipment heat conduction system exploded view;

[0037] Figure 1B A conventional electronic equipment heat conduction system side view (I);

[0038] Figure 1C A conventional electronic equipment heat conduction system side view (II);

[0039] Figure 2A A schematic view of an existing graphene film;

[0040] Figure 2B A Figure 2A An enlarged view of the structure referred to in 2B;

[0041] Figure 3A An exploded perspective view of the disclosed prior art CN 114181639A;

[0042] Figure 3B A completed view of the disclosed prior art CN 114181639A;

[0043] Figure 4 For the patent announcement No. CN 215527717U is a perspective view;

[0044] Figure 5A For the appearance perspective view of the graphene film of the utility model;

[0045] Figure 5B For the Figure 5A The structure of the part indicated in 5B of the utility model is enlarged;

[0046] Figure 6A For the hole arrangement schematic view of the graphene film of the utility model;

[0047] Figure 6B For another hole arrangement schematic view of the graphene film of the utility model;

[0048] Figure 7 For the exploded perspective view of the graphene film and silica gel stack of the utility model;

[0049] Figure 8 For the graphene film and silica gel composite material block perspective view of the utility model;

[0050] Figure 9 For the graphene film and silica gel composite material block cutting schematic view of the utility model;

[0051] Figure 10 For the perspective view of the stack-shaped slice of the utility model;

[0052] Figure 11A For the front view of the stack-shaped slice of the utility model;

[0053] Figure 11B For the Figure 11A The partial structure of the part indicated in 11B of the utility model is enlarged schematic view;

[0054] Figure 12A For the front view of the stack-shaped slice of the utility model;

[0055] Figure 12B For the Figure 12A The partial structure of the part indicated in 12B of the utility model is enlarged schematic view;

[0056] Figure 13A For the front view of the graphene fiber filling of the utility model;

[0057] Figure 13B For the Figure 13A The partial structure of the part indicated in 13B of the utility model is enlarged schematic view;

[0058] Figure 14A A schematic view of the vertical multi-layer graphene heat conduction sheet of the utility model under pressure;

[0059] Figure 14B A use state reference drawing of the utility model;

[0060] Figure 15A A schematic view of the horizontal (X-Y) and vertical (Z) heat conduction of a general graphene film;

[0061] Figure 15B A schematic view of the vertical multi-layer graphene heat conduction sheet of the utility model under pressure;

[0062] Marking in the drawing:

[0063] 10 Electronic device;

[0064] 11 Circuit board;

[0065] 12 Electronic component;

[0066] 13 Heat sink;

[0067] 40 Graphene film;

[0068] 41 Hole;

[0069] 40a First graphene film;

[0070] 40b Second graphene film;

[0071] 40n Nth graphene film;

[0072] 50 Silicone;

[0073] 50a First silicone layer;

[0074] 50b Second silicone layer;

[0075] 51 Hollow part;

[0076] 60A Horizontal graphene film and silicone layer stack;

[0077] 60B Horizontal graphene film and silicone composite block;

[0078] 70A Stacked slice;

[0079] 70B Vertical multi-layer graphene heat conduction sheet;

[0080] 71 Graphene fiber. DETAILED DESCRIPTION

[0081] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0082] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0083] Please refer to Appendix 5 to Appendix 6 below. Figure 15B This invention describes a multi-layered graphene thermal conductive sheet with strong bonding and resilience, comprising the following steps:

[0084] Step S01: As Figure 5A , Figure 5B As shown, a plurality of graphene films 40 and silicone adhesive 50 are provided; each graphene film 40 is first perforated by a laser to form a plurality of holes 41 with a diameter of 0.1 mm to 1 mm; this 0.1 mm hole diameter (d1) is the smallest hole diameter that can be implemented by laser perforation, and a hole diameter of less than 1 mm can avoid excessive silicone adhesive 50 penetrating into a single hole 41, which would affect the flexibility and thermal conductivity of the graphene film 40.

[0085] Figure 6A The diagram shown illustrates the arrangement of the pores 41 in the graphene film 40, which exhibits an alternating arrangement, but is not limited to this; it can also be arranged as follows: Figure 6B The diagram shows an array of neatly arranged holes, or other arrangements. Importantly, the aperture (d1), spacing (D), and surface area occupied by each hole 41 are determined based on the desired bonding strength and resilience of the graphene film 40. In other words, to achieve stronger bonding strength in the graphene film 40, all holes 41 need to occupy a larger surface area, resulting in a larger aperture (d1). Conversely, to improve the resilience of the graphene film 40, the aperture (d1) will be smaller, preserving the inherent elasticity of the graphene film 40. This invention optimizes the balance between bonding strength and resilience by pre-adjusting the aperture (d1) and spacing (D) according to the size, area, and product requirements.

[0086] In this embodiment, the graphene film 40 has a thickness of 10μm to 100μm, a length of 5cm to 30cm or a roll shape, and a width of 5cm to 30cm. The silicone 50 has a coating thickness of 0.01mm to 0.1mm, a length of 5cm to 30cm, and a width of 5cm to 30cm.

[0087] Step S02: The perforated graphene film 40 is irradiated with an ultraviolet lamp for 1-2 minutes to generate hydrophilic functional groups on the surface of the graphene film 40. This step is beneficial for the wetting of the silicone 50, so that the graphene film 40 and the silicone 50 have better bonding in subsequent processes.

[0088] Step S03: As Figure 7 As shown, a first silicone layer 50a is coated on the surface of a first graphene film 40a.

[0089] Step S04: Place a second graphene film 40b on the first silicone layer 50a.

[0090] Step S05: Allow a portion of the first silicone layer 50a to penetrate into the pores 41 of the first graphene film 40a and the second graphene film 40b.

[0091] Step S06: As Figure 8 As shown, by repeating steps S04 and S05 above, a horizontal graphene film and silicone layer stack 60A is obtained; in this embodiment, the thickness of the graphene film and silicone layer stack 60A can be 5cm to 30cm. That is, preferably, the graphene film and silicone layer stack 60A can be a cube of 5cm to 30cm, but it is not limited to this.

[0092] Step S07: The transverse graphene film and silicone layer stack 60A are cured to form a transverse graphene film and silicone composite material block 60B, as shown. Figure 8 As shown; in this embodiment, the preferred curing method includes placing the transverse graphene film and the silicone stack 60B into an oven for heating and curing, but is not limited to this.

[0093] Step S08: As Figure 9 As shown, the transverse graphene film and silicone composite block 60B is vertically cut along the direction of stack thickness (Z-axis) at intervals of 0.15mm to 5mm to form a plurality of stacked slices 70A.

[0094] Step S09: As Figure 10 As shown, the stacked slice 70A is flipped 90 degrees and laid flat. Its structure at this point is as follows: Figure 11A , Figure 11BAs shown, the silica gel layers are between the longitudinal graphene films, and the silica gel also permeates into the transverse holes 41, forming a longitudinal and transverse interlaced combination mode.

[0095] Step S10: as shown in Figure 12A 、 Figure 12B The upper and lower end faces of the stacked slice 70A are subjected to silica removal to form the hollow portions 51. The silica gel 50 between the graphene films 40 is mostly removed by the silica removal of the stacked slice 70A, so that the silica gel 50 is lower than the graphene films 40 and presents a concave shape, only a part of the connecting surface is reserved, and the graphene films 40 are mostly hollow portions 51. In this embodiment, the silica removal of the stacked slice 70A includes laser or solvent cleaning of the silica gel on the upper and lower end faces, but is not limited thereto.

[0096] Step S11: as shown in Figures 13A-13B Graphene fibers 71 are filled in the hollow portions 51 to connect the graphene films to each other, so that a vertical multi-level graphene heat-conducting sheet 70B with a thickness of 0.15-5 mm, strong bonding force and resilience is formed. In this embodiment, the method for filling graphene includes grinding the surface of the stacked slice 70A to form a plurality of graphene fibers 71 in the hollow portions 51, but is not limited thereto.

[0097] The vertical multi-level graphene heat-conducting sheet 70B with strong bonding force and resilience prepared by the above technical means has the following structure:

[0098] A plurality of graphene films 40 and silica gel 50 form a plurality of holes 41 with a diameter of 0.1-1 mm on the graphene films 40, and hydrophilic functional groups are generated on the surface of the graphene films 40;

[0099] A first silica gel layer 50a is coated on the surface of a first graphene film 40a, and a second graphene film 40b is placed on the first silica gel layer 50a; a part of the first silica gel layer 50a permeates into the holes 41 of the first graphene film 40a and the second graphene film 40b;

[0100] Then, a second silica gel layer 50b is coated on the surface of the second graphene film 40b, and the above-mentioned stacking of graphene films and silica gel layers is repeated to obtain a transverse graphene film and silica gel layer stack 60A;

[0101] The transverse graphene film and silica gel layer stack 60A is cured to form a transverse graphene film and silica gel composite block 60B;

[0102] Along the direction of the stacked thickness, the transverse graphene film and silicone composite block 60B is vertically cut at intervals of 0.15mm to 5mm to form a plurality of stacked slices 70A;

[0103] The stacked slice 70A was flipped 90 degrees and laid flat.

[0104] The top and bottom surfaces of the stacked slice 70A are de-adhesive-removed to form a hollow section 51; and

[0105] Graphene fibers 71 are filled in the hollowed-out portion 51 so that the graphene films between the stacked slices 70A can be connected to each other to form a vertical multi-layered graphene heat-conducting sheet 70B with a thickness of 0.15mm to 5mm and strong bonding and resilience.

[0106] Therefore, as Figure 13B As shown, in the vertical multi-layered graphene thermal conductive sheet 70B prepared according to the preceding steps, most of the graphene films 40 are vertical (vertical along the X-axis), and the graphene films 40 are evenly distributed and have consistent thermal conductivity, allowing heat conduction along the longitudinal direction (X-axis), thus avoiding heat accumulation caused by transverse conduction. Furthermore, the hydrophilic functional groups generated on the surface of the graphene films 40 have a strong bonding force with the silicone 50, and the hollow portions 51 are filled with graphene fibers 71, enabling the graphene films between the stacked slices 70A to be interconnected. This effectively solves the problem of the graphite-like structure inside traditional graphene thermal conductive films, which easily causes delamination, affecting the overall mechanical stability and posing a serious risk of cracking.

[0107] More importantly, its effects are as follows Figure 14A The diagram shows the deformation of the vertical multi-layered graphene heat-conducting sheet 70B under pressure. Due to the filling of graphene fibers 71, the upper and lower surface layers of the vertical multi-layered graphene heat-conducting sheet 70B do not lose their original elasticity and become incompressible like traditional graphene, which is already solidified. Instead, the vertical multi-layered graphene heat-conducting sheet 70B of this invention possesses resilience, meaning it is compressible. When pressure (P) is applied, it exhibits resistance to compression. When the height (H1) is compressed to (H2), it possesses an elastic buffering force that resists compression, releasing a reverse elasticity. This characteristic is indeed necessary and has substantial benefits in practical applications of heat dissipation products, as explained below.

[0108] Figure 14BAs shown in a use state reference drawing of the utility model, a vertical multi-layer graphene heat conduction sheet 70B with a thickness of 0.15mm-5mm is implemented in an electronic device 10, the vertical multi-layer graphene heat conduction sheet 70B is arranged between the electronic element (for example, a semiconductor chip) 12 and the heat sink 13, since the vertical multi-layer graphene heat conduction sheet 70B is soft and elastic, the gap between the electronic element 12 and the heat sink 13 can be filled, thereby the thermal resistance between the electronic element 12 and the heat sink 13 can be reduced, the electronic device 10 can operate at a normal operating temperature, thereby the stability and service life of the electronic device can be improved. The vertical multi-layer graphene heat conduction sheet 70B has an elastic buffering force, in this way, the electronic element 12 is not easily damaged by the pressure of the heat sink 13. Therefore, the vertical multi-layer graphene heat conduction sheet (LGS) 70B prepared by the utility model has the following product advantages: 1. The module does not need to be protected from liquid gold leakage. 2. The construction is simple, and the product can be directly attached to the CPU. 3. High reliability and weather resistance, not easy to oxidize. 4. The material is soft and not easy to expand and press the module. 5. It has a certain structural strength and is not easy to have local material defects in the interface after long-term use.

[0109] Figure 15A The heat conduction diagram of the horizontal direction (X-Y direction) and the vertical direction (Z direction) of the general graphene film is shown, the heat conduction coefficient of the horizontal direction (X-Y direction) of the conventional graphene 30 can reach 1500 W / m.k. But the heat conduction coefficient of the vertical direction (Z direction) is only 15 W / m.k. Therefore, the utility model utilizes the horizontal heat conduction characteristics of graphene, changes the horizontal direction (X-Y direction) into the vertical direction by the preparation method, and the obtained vertical multi-layer graphene heat conduction sheet (LGS) 70B has the heat conduction characteristics as Figure 15B As shown by the arrow, high heat conduction performance can be obtained in the vertical direction, and the structure of the heat conduction sheet is stable when it is pressed and rebounded.

[0110] Based on the above technical features, the vertical multi-layer graphene heat conduction sheet (LGS) 70B prepared by the utility model is an artificial graphene and silicone composite material. The product has high thermal conductivity, low contact thermal resistance, high compression, high and low temperature resistance and other characteristics, effectively fills the gap between the heating end and the cooling end, realizes efficient heat transfer between the heating part and the heat dissipation part, and simultaneously plays a shock absorbing and anti-collision role.

[0111] Therefore, the vertical multi-layered graphene thermal conductive sheet with strong bonding and resilience prepared by this invention has the following breakthroughs that need to be explained: First, the vertical multi-layered graphene thermal conductive sheet 70B prepared by this invention first has holes drilled in each graphene film 40 using a laser at the beginning of the process, allowing the silicone in the process to penetrate into each hole 41, forming a plurality of holes 41, so that the graphene films 40 can be interconnected, and the polymers can form a completely continuous structure. Not only does it have good bonding and high orientation, but the graphene fibers in the multi-layered graphene thermal conductive sheet can maintain synchronization with the polymer under pressure and rebound, and can withstand high compression rates without cracking, fundamentally solving the cracking problem of conventional graphene thermal conductive sheets. II. The vertical multilayer graphene thermal conductive sheet 70B prepared by this utility model has the following characteristics: because the silicone at the upper and lower ends of each graphene film 40 is removed, only the connecting surface in the middle is retained, and the interior of the upper and lower hollowed-out portions 51 is graphene fiber 71, the vertical multilayer graphene thermal conductive sheet 70B has the characteristics of flexibility and resilience. Figure 14B As shown, damage to electronic components (semiconductor chips) 12 can be avoided during the fastening process of operating electronic devices. III. The vertical multi-layered graphene thermal conductive sheet 70B prepared by this invention has graphene fibers 71 evenly distributed between each graphene film 40, exhibiting consistent thermal conductivity. It can conduct heat along the longitudinal direction, thereby avoiding heat accumulation caused by heat conduction along the lateral direction.

[0112] In conclusion, the technical means disclosed in this utility model do possess the novelty, progressiveness, and industrial applicability required for a utility model patent. We respectfully request that Your Excellency grant us a patent to encourage invention. We are deeply grateful for your assistance.

[0113] The drawings and descriptions disclosed above are merely preferred embodiments of this utility model. Modifications or equivalent changes made by those skilled in the art within the spirit and scope of this application should still be included within the scope of the patent application.

Claims

1. A multi-layered graphene thermal conductive sheet having strong bonding force and resilience, characterized in that, The application relates to a vertical multi-layer graphene heat-conducting sheet. A plurality of graphene films and silica gels are provided, a plurality of holes with a diameter of 0.1mm-1m are formed on each graphene film, and a hydrophilic functional group is generated on the surface of the graphene film. A first silica gel layer is coated on the surface of a first graphene film, and a second graphene film is placed on the first silica gel layer; a part of the first silica gel layer penetrates into the holes of the first graphene film and the second graphene film. A second silica gel layer is coated on the surface of the second graphene film, and the graphene film and the silica gel layer are stacked repeatedly to obtain a horizontal graphene film and silica gel layer stack. The horizontal graphene film and silica gel layer stack is solidified to form a horizontal graphene film and silica gel composite material block. The horizontal graphene film and silica gel composite material block is vertically cut along the stacking direction at an interval of 0.15mm-5mm to form a plurality of stacked slices; the stacked slices are turned by 90 degrees to lie flat. The upper and lower end faces of the stacked slices are subjected to glue removal to form a hollow part; and graphene fibers are filled in the hollow part, so that the graphene films between the stacked slices are connected to each other to form a vertical multi-layer graphene heat-conducting sheet with a thickness of 0.15mm-5mm, strong bonding force and elasticity.

2. The multi-layered graphene thermal sheet having high bonding force and resilience according to claim 1, wherein, The graphene film has a thickness of 10um-100um, a length of 5cm-30cm or a roll form, and a width of 5cm-30cm; the silica gel has a coating thickness of 0.01mm-0.1mm, a length of 5cm-30cm and a width of 5cm-30cm.

3. The multi-layered graphene thermal sheet having high bonding force and resilience according to claim 2, wherein, The horizontal graphene film and silica gel layer stack has a thickness of 5cm-30cm.

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