Multi-layer graphene heat-conducting sheet with strong bonding force and resilience and preparation method thereof

Abstract

This invention discloses a multi-layered graphene thermal conductive sheet with strong bonding and resilience, comprising: a plurality of graphene films, perforated by a laser and irradiated with an ultraviolet lamp for 1-2 minutes; a first silicone layer coated on the surface of the first graphene film; a second graphene film placed on the first silicone layer; allowing a portion of the first silicone layer to penetrate into the pores of the first and second graphene films; repeating the above stacking to form a transverse graphene film and silicone composite material block; cutting along the stack thickness direction to form a plurality of stacked slices; then removing the adhesive from the upper and lower end faces to form a hollow portion, followed by graphene fiber filling to allow the graphene films to connect with each other, resulting in a multi-layered graphene thermal conductive sheet with strong bonding and resilience. Therefore, the graphene has good bonding properties and can withstand high compression rates without cracking, fundamentally solving the cracking problem of conventional graphene thermal conductive sheets.

Description

Technical Field

[0001] This invention relates to a graphene thermal conductive sheet, and more particularly to a vertical multi-layered graphene thermal conductive sheet with strong bonding and resilience, characterized by high thermal conductivity, low contact thermal resistance, high compression, resistance to high and low temperatures, etc. Background Technology

[0002] In recent years, the rapid development of high-power semiconductor components such as central processing units (CPUs) and graphics processing units (GPUs), coupled with the increasing thinness and multi-functionality of electronic devices, has led to localized overheating after prolonged use due to the increased density and frequency of electronic components (e.g., chips, integrated circuits, transistors). Chips are typically the primary heat source during operation, and heat dissipation is crucial not only for lowering their own temperature to ensure normal operation within the required temperature range but also for preventing localized overheating of the casing, which could negatively impact the user experience. Previously, heat dissipation in electronic devices primarily relied on simple methods such as openings, heat conduction, and heat convection. However, these methods are no longer sufficient to handle the heat generated by today's high-performance chips, resulting in overheating problems. Uneven heat distribution reduces the internal heat dissipation efficiency of electronic devices, leading to frequent instances of system throttling, slowdowns, or crashes.

[0003] like Figures 1A-1C As shown, a typical electronic device 10 mainly includes: an electronic component 12 mounted on a circuit board 11, a heat sink 13, and a "heat transfer sheet" or "heat conduction sheet" 20 disposed between the electronic component 12 and the heat sink 13, which is used to transfer the heat generated by the electronic component 12. Currently, the commonly used "heat conduction sheet" 20 in the industry is a thermally conductive silicone (silicone) film. Traditional thermally conductive silicone films on the market are generally formulated from silicone oil, thermally conductive powder, and other additives. Its thermal conductivity relies on the thermally conductive powder in the formula, which is generally alumina, aluminum nitride, etc. Because it is a powder, the particles cannot be in complete contact, resulting in high thermal resistance. Furthermore, the thermal conductivity is generally limited to 6W~10W / mK, making it very difficult and costly to obtain silicone films with higher thermal conductivity. Moreover, as shown in Figure 2, when the thickness (t1) of the thermally conductive silicone film 20A is thicker, the thermal resistance increases, limiting the thermal conductivity.

[0004] For example Figure 1CAs shown, when the thickness (t2) of the thermally conductive silicone (silicone) film 20B is thin, the heat dissipation effect is limited. Furthermore, when the thickness of the thermally conductive silicone (silicone) film 20B is too thin, it cannot effectively fill the gaps between electronic components or heat sinks, resulting in limited reduction of interface thermal resistance. With the development of technology, the requirements for the thermal conductivity system of thermally conductive silicone sheets are becoming increasingly stringent, and current thermally conductive silicone (silicone) films can no longer meet existing needs. Therefore, it is essential to develop thermally conductive sheets that can significantly improve thermal conductivity.

[0005] Another commonly used "thermal conductive sheet" in the industry includes those made of materials with high thermal conductivity such as copper, aluminum, and graphite, namely thermally conductive copper foil, thermally conductive aluminum foil, or thermally conductive graphite sheets. The advantage of this type of thermal conductive sheet is its excellent thermal conductivity, but the disadvantage is that materials with high thermal conductivity such as copper, aluminum, and graphite, unlike thermally conductive silicone pads, are not flexible and elastic. Therefore, in practical applications, it is difficult for them to adaptably deform along the surfaces of the electronic component 12 and the heat sink 13, thus failing to effectively adhere to the gap between the electronic component 12 or the heat sink 13, resulting in limited performance in reducing interface thermal resistance. More importantly, the "thermal conductive sheet" is a rigid material, lacking flexibility and elasticity, making it easy to damage semiconductor chips during the snap-fit ​​process of the electronic device 10. Therefore, traditional thermally conductive silicone (silicon) sheets, or thermal conductive sheets made of materials with high thermal conductivity such as copper, aluminum, and graphite, all have their shortcomings.

[0006] like Figure 2A and Figure 2B As shown, "graphite" is composed of many layers of "graphene"30 stacked together. This man-made nanomaterial possesses high thermal conductivity due to the hexagonal structure31 of carbon atoms. This structure allows carbon atoms to be firmly bonded together, enabling electrons to move freely between them. In one published paper, a graphene thermally conductive film was impregnated in epoxy resin, then laminated, cured, and cut into a graphene thermally conductive film / epoxy resin composite material with longitudinally aligned graphene thermally conductive films. The longitudinal thermal conductivity reached over 384.9 W / (m·K) to 1000 W / (m·K). However, the graphene thermally conductive film / epoxy resin composite material obtained by this method is a rigid material, which cannot fully contact the interface, resulting in high thermal resistance and making it unsuitable as a thermal interface material.

[0007] Furthermore, in existing technologies, graphene is generally made into thermally conductive powder and then arranged vertically to create a high-thermal-conductivity sheet, as shown in Chinese patents CN113337253A, CN113560146A, CN113789590A, etc. This type of patent, where graphene is made into powder, lacks a continuous structure, resulting in high thermal resistance between the powder particles within the sheet and relatively low thermal conductivity. The thermal conductivity of graphene powder is generally above 900 W / (mK). To simultaneously meet the requirements for thermal conductivity, thermal resistance, compressibility, and compression resilience of the sheet, its filler content is unlikely to exceed 50 wt.%, resulting in a thermally conductive sheet with a thermal conductivity generally not exceeding 25 W / (mK). Increasing the filler content to improve thermal conductivity can lead to excessive hardening and cracking.

[0008] Furthermore, in the prior art, there are methods that directly use graphene thermal conductive films to stack layer by layer and arrange them along the longitudinal direction to obtain a graphene fiber-reinforced thermal conductive sheet with high longitudinal thermal conductivity. Examples of this type can be found in Chinese patent publications CN113290958A, CN113183544A, etc.

[0009] Although this type of patent creates a continuous graphene structure, the graphene thermal conductive film hinders the formation of connections between the polymer layers. Furthermore, the graphene thermal conductive film itself is prone to delamination, leading to a tendency for the resulting thermal conductive sheet to crack. While through-holes can be added to the graphene thermal conductive film, this only increases the number of connection points and cannot create a completely continuous structure between the polymers, thus failing to fundamentally solve the cracking problem of the resulting thermal conductive sheet.

[0010] Chinese Patent Publication CN113556925A discloses a thermally conductive pad comprising reinforcing fibers, a thermally conductive film, and an adhesive. The reinforcing fibers are interwoven side-by-side within the thermally conductive film, giving it a stable wavy structure. The adhesive fills the gaps in the wavy structure, forming a tightly bonded thermally conductive pad. This thermally conductive pad exhibits good thermal conductivity and compression resilience in the longitudinal direction. Furthermore, Chinese Patent Publication CN110491845A also describes a method of transforming a graphene thermally conductive film from a planar direction to a longitudinal arrangement through pleating, followed by coating with an adhesive to form a monolithic structure. In this type of patent, the graphene thermally conductive film has a graphite-like internal structure, which is prone to delamination, affecting not only the overall mechanical stability but also posing a serious risk of cracking.

[0011] Shenzhen Hongfucheng New Materials Co., Ltd. has disclosed several methods for preparing graphene thermal conductive pads, one of which is: Chinese Patent Publication No. CN 114181639A, a method for preparing a self-adhesive graphene thermal conductive pad, such as... Figure 3Aand 3B As shown, the method is characterized by the following steps: S1. Coating an adhesive (82) onto the first graphene film (81), then placing the second graphene film (81) onto the first graphene film (81), and coating the second graphene film (81) with another layer of adhesive (82) and stacking the third graphene film (11), repeating this process until the target height is reached. After the adhesive is cured, a graphene film block (83) is obtained; S2. Opening a through-hole on both sides of the graphene film block (83) on the graphene film block (83). S3. Fill the through hole (84) along the stacking direction of the graphene film; S4. Fill the through hole (84) with thermally conductive filler, and after the thermally conductive filler is fixed in the through hole (84), a three-dimensional structure of graphene-thermally conductive filler is formed; S5. Slice the three-dimensional structure of graphene-thermally conductive filler along the stacking direction of the graphene film to obtain a thermally conductive layer (80) of a specified thickness; S6. Apply adhesive to both sides of the graphene thermally conductive pad along the thickness direction, and after the adhesive is cured, an adhesive layer (90) is formed, and a self-adhesive graphene thermally conductive pad with self-adhesion is obtained.

[0012] The second example is Chinese Patent Publication No. CN 114213986 A, which specifically discloses a thermally conductive and insulating graphene gasket and its preparation method. The thermally conductive and insulating graphene gasket comprises a graphene block consisting of multiple layers of graphene film. Carbon fiber filaments are fixedly inserted within the graphene block, arranged along the thickness direction of the graphene block to form a three-dimensional thermally conductive graphene-carbon fiber structure. An insulating layer is fixedly connected along the horizontal direction of the graphene block, and the insulating layer contains anisotropic boron nitride.

[0013] The third one: Chinese utility model patent announcement CN 215527717U, provides a graphene thermal conductive pad, such as Figure 4 As shown, it includes: multiple layers of graphene film (91) stacked sequentially, an adhesive layer (92) is provided between two adjacent graphene film (91) layers, and the two adjacent graphene film (91) layers are connected by the adhesive layer (92); through holes are opened on the graphene film (91) along the stacking direction, and carbon fiber filaments (93) are fixed in the through holes.

[0014] The aforementioned public applications from Shenzhen Hongfucheng New Materials Co., Ltd. all involve coating a layer of adhesive onto a multilayer graphene film, then repeatedly stacking the layers until a target height is reached. After the adhesive cures, a graphene film block is obtained. However, because the structure of the graphene film itself is loose, the bonding force is insufficient, and it is easy to separate. Therefore, in the application CN 114181639A, through-holes penetrating both sides of the graphene film block are then opened on the graphene film block, and thermally conductive filler is then filled into the through-holes to form a three-dimensional graphene-thermally conductive filler structure. In the application CN 215527717U, carbon fiber filaments are inserted and fixed within the graphene block. In the application CN 215527717U, through-holes are opened along the stacking direction on the graphene film, and carbon fiber filaments are fixed within the through-holes.

[0015] Although the aforementioned design utilizes through-holes in the graphene film block and then uses thermally conductive fillers or carbon fiber filaments to increase its bonding strength, this design presents two problems: First, after the graphene film block (83) has solidified, it is difficult to fabricate through-holes (84) and then fill them with thermally conductive fillers or carbon fiber filaments. This is because the pore size of the through-holes (84) is very small, only 0.1~0.5mm. Second, when the graphene film block (83) is sliced ​​along the stacking direction of the graphene film (81) to obtain a thermally conductive layer (1) of a specified thickness, it has already solidified and lost the original elasticity of graphene, becoming incompressible.

[0016] Based on the aforementioned prior art analysis, and considering the application requirements of heat-conducting sheets, achieving high thermal conductivity in the longitudinal direction while ensuring structural stability under pressure and rebound is a crucial issue. Therefore, in view of these problems, the inventors have proposed a solution to address the shortcomings of commonly used heat-conducting sheets in the industry. Summary of the Invention

[0017] The purpose of this invention is to provide a multi-layered graphene thermal conductive sheet with strong bonding and resilience, and its preparation method. The invention provides a vertical multi-layered graphene thermal conductive sheet with strong bonding and resilience. The product has the characteristics of high thermal conductivity, low contact thermal resistance, high compression, and resistance to high and low temperatures. It 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 at the same time plays a role in shock absorption and impact protection.

[0018] To achieve the above objectives, the specific technical solution of the present invention, a multi-layered graphene thermal conductive sheet with strong bonding and resilience, and its preparation method, is as follows: A method for preparing a multi-layered graphene thermal conductive sheet with strong bonding and resilience, comprising: Step S01: Provide a plurality of graphene films, and first use a laser to drill holes in each graphene film to form a plurality of holes with a diameter of 0.1mm to 1mm. The diameter of the holes and the surface area they occupy are set according to the required bonding strength and resilience of the graphene film. Step S02: Irradiate the perforated graphene film with an ultraviolet lamp for 1-2 minutes to generate hydrophilic functional groups on the surface of the graphene film; Step S03: Coat a first silicone layer onto the surface of a first graphene film; Step S04: Place a second graphene film on the first silicone layer; Step S05: Allow a portion of the first silicone layer to penetrate into the pores of the first and second graphene films; Step S06: Coat the surface of the second graphene film with a second silicone layer; repeat steps S04 and S05 above to obtain a transverse graphene film and silicone layer stack. Step S07: The lateral graphene film and silicone layer stack is cured to form a lateral graphene film and silicone composite material block; Step S08: Along the direction of stack thickness, vertically cut the transverse graphene film and silicone composite material block at intervals of 0.15mm to 5mm to form numerous stacked slices; Step S09: Flip the stacked slices 90 degrees and lay them flat; Step S10: Remove the adhesive from the top and bottom surfaces of the stacked slices to form a hollow section; Step S11: Graphene fiber filling is performed at the hollowed-out area so that the graphene films can be interconnected to form a vertical multi-layered graphene heat-conducting sheet with a thickness of 0.15mm to 5mm, strong bonding force and resilience.

[0019] Furthermore, in step S01, the graphene film has a thickness of 10μm to 100μm, a length of 5cm to 30cm or in roll form, and a width of 5cm to 30cm; the silicone coating has a thickness of 0.01mm to 0.1mm, a length of 5cm to 30cm, and a width of 5cm to 30cm.

[0020] Furthermore, in step S06, the thickness of the graphene film and the silicone layer stack is 5cm to 30cm.

[0021] Furthermore, in step S10, the stacked slices undergo a desmearing process, which includes removing the silicone from the upper and lower end faces using a laser or a solvent.

[0022] Furthermore, in step S11, the graphene fiber filling operation performed at the hollow portion includes grinding or ultrasonic processing of the surface of the stacked slices to form numerous graphene fibers in the hollow portion.

[0023] The fabricated multi-layered graphene thermal conductive sheet with strong bonding and resilience comprises: a plurality of graphene films and silicone, wherein a plurality of pores with a diameter of 0.1 mm to 1 μm are formed on each graphene film, and hydrophilic functional groups are generated on the surface of the graphene film; a first silicone layer is coated on the surface of a first graphene film, and a second graphene film is placed on the first silicone layer; a portion of the first silicone layer penetrates into the pores of the first and second graphene films; then, a second silicone layer is coated on the surface of the second graphene film, and the stacking of the graphene films and silicone layers is repeated to obtain a transverse graphene film and silicone layer stack. The transverse graphene film and silicone layer stack are cured to form a transverse graphene film and silicone composite material block; the transverse graphene film and silicone composite material block is vertically cut at intervals of 0.15mm to 5mm along the stack thickness direction to form a plurality of stacked slices; the stacked slices are flipped 90 degrees and laid flat; the adhesive is removed from the upper and lower end faces of the stacked slices to form a hollow part; and graphene fibers are filled in the hollow part so that the graphene films between the stacked slices can be interconnected to form a vertical multi-layered graphene thermal conductive sheet with a thickness of 0.15mm to 5mm and strong bonding and resilience.

[0024] Using the aforementioned technical means, the vertical multi-layered graphene thermal conductive sheet prepared by this invention, possessing strong bonding and resilience, exhibits the following breakthroughs that need to be explained: First, in the vertical multi-layered graphene thermal conductive sheet prepared by this invention, holes are first drilled in each graphene film using a laser at the beginning of the manufacturing process. This allows the silicone used in the process to penetrate into each hole, forming numerous pores that interconnect the graphene films, creating a completely continuous structure between the polymers. This not only results in excellent bonding and high orientation, but also ensures that the graphene fibers in the multi-layered graphene thermal conductive sheet maintain synchronization with the polymer under pressure and rebound, allowing it to withstand high compression rates without cracking, fundamentally solving the cracking problem of conventional graphene thermal conductive sheets. II. The vertical multi-layered graphene thermal conductive sheet prepared by this invention has the silicone removed from the upper and lower ends of each graphene film, leaving only the connecting surface in the middle. The interior of the upper and lower hollowed-out portions contains graphene fibers. Therefore, the vertical multi-layered graphene thermal conductive sheet possesses flexibility and elasticity, preventing damage to electronic components (semiconductor chips) during the fastening process of electronic devices. III. The vertical multi-layered graphene thermal conductive sheet prepared by this invention has uniformly distributed graphene fibers between each graphene film, resulting in consistent thermal conductivity. It allows for longitudinal heat conduction, thus preventing heat accumulation caused by transverse heat conduction. Therefore, the product features high thermal conductivity, low contact thermal resistance, high compressibility, and resistance to high and low temperatures. It effectively fills the gap between the heating and cooling ends, achieving efficient heat transfer between the heating and cooling components, while also providing shock absorption and impact protection. Attached Figure Description

[0025] Figure 1A An exploded view of a conventional electronic device thermal management system; Figure 1B A side view of a conventional electronic device thermal conductivity system (I); Figure 1C Side view of a conventional electronic device thermal conductivity system (II); Figure 2A This is a schematic diagram of an existing graphene film; Figure 2B for Figure 2A The enlarged view of the structure referred to in 2B; Figure 3A An exploded perspective view of prior art disclosed in Chinese Patent No. CN 114181639A; Figure 3B The completed drawing is for Chinese Patent Publication No. CN 114181639A (Prior Art). Figure 4 A perspective view of patent publication CN 215527717U; Figure 5AThis is a perspective view of the graphene film of the present invention; Figure 5B For the present invention Figure 5A Enlarged view of the structure referred to in 5B; Figure 6A This is a schematic diagram of the pore arrangement of the graphene film of the present invention; Figure 6B This is a schematic diagram of another pore arrangement in the graphene film of the present invention; Figure 7 This is an exploded perspective view of most of the transverse graphene films and silicone stacks of the present invention. Figure 8 This is a perspective view of the transverse graphene film and silicone composite material block of the present invention; Figure 9 This is a schematic diagram showing the cutting of the transverse graphene film and silicone composite material block according to the present invention; Figure 10 This is a perspective view of the stacked slices of the present invention; Figure 11A This is a front view of the stacked slices of the present invention; Figure 11B For the present invention Figure 11A Enlarged schematic diagram of the part of the structure referred to in section 11B; Figure 12A A front view of the stacked slices of the present invention, showing the process of removing adhesive to form a hollow portion; Figure 12B For the present invention Figure 12A Enlarged schematic diagram of the part of the structure referred to in 12B; Figure 13A A front view showing the graphene fiber filling of the hollow portion of the present invention; Figure 13B For the present invention Figure 13A Enlarged schematic diagram of the part of the structure referred to in section 13B; Figure 14A This is a schematic diagram of the vertical multilayer graphene heat-conducting sheet of the present invention under pressure. Figure 14B This is a reference diagram showing a usage state of the present invention; Figure 15A This diagram illustrates the thermal conductivity of a typical graphene film in the transverse (XY) and longitudinal (Z) directions. Figure 15B This is a schematic diagram of the thermal conductivity of the vertical multi-layered graphene thermal conductive sheet of the present invention. Explanation of markings in the diagram: 10. Electronic devices; 11. Circuit board; 12. Electronic components; 13. Radiator; 40 Graphene film; 41. Holes; 40a First Graphene Film; 40b second graphene film; 40n The nth layer of graphene film; 50 silicone; 50a First silicone layer; 50b Second silicone layer; 51. Openwork section; 60A Lateral graphene film and silicone layer stack; 60B transverse graphene film and silicone composite block; 70A stacked sections; 70B Vertical Multilayer Graphene Thermal Conductor; 71. Graphene fiber. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] 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 the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0028] 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, and its preparation method, the steps of which include: 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.

[0029] 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 cells, or other arrangements. Importantly, the aperture (d1), spacing (D), and surface area occupied by the holes 41 are determined based on the desired bonding strength and resilience of the graphene film 40. That is, 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.

[0030] 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.

[0031] 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.

[0032] Step S03: As Figure 7 As shown, a first silicone layer 50a is coated on the surface of a first graphene film 40a.

[0033] Step S04: Place a second graphene film 40b on the first silicone layer 50a.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 11B As shown, there are silicone layers between the vertical graphene films, and silicone is also infiltrated into the transverse pores 41, forming a crisscrossing combination pattern.

[0039] Step S10: As Figure 12A , Figure 12B As shown, the top and bottom surfaces of the stacked slice 70A are de-adhesive-removed to form a hollow portion 51. The de-adhesive-removal process on the stacked slice 70A removes most of the surface of the silicone 50 between the graphene films 40, causing the silicone 50 to be recessed below the graphene films 40, retaining only a portion of the connecting surfaces, thus forming a hollow portion 51 between the graphene films 40. In this embodiment, the de-adhesive-removal process on the stacked slice 70A includes, but is not limited to, removing the silicone from the top and bottom surfaces using a laser or a solvent.

[0040] Step S11: As Figures 13A-13B As shown, graphene fibers 71 are filled into the hollow portion 51, allowing the graphene films to connect with each other, forming a vertical multi-layered graphene thermal conductive sheet 70B with a thickness of 0.15mm to 5mm and strong bonding and resilience. In this embodiment, the method of filling the graphene includes grinding the surface of the stacked slice 70A to form numerous graphene fibers 71 in the hollow portion 51, but is not limited to this method.

[0041] The vertical multi-layered graphene thermal conductive sheet 70B with strong bonding and resilience, prepared according to the aforementioned technical means of the present invention, comprises the following structure: Most of the graphene films 40 and silicone 50 have a plurality of pores 41 with a diameter of 0.1 mm to 1 mm formed on each graphene film 40, and hydrophilic functional groups are generated on the surface of the graphene film 40; A first silicone layer 50a is coated on the surface of a first graphene film 40a, and a second graphene film 40b is placed on the first silicone layer 50a; a portion of the first silicone layer 50a penetrates into the pores 41 of the first graphene film 40a and the second graphene film 40b. Next, a second silicone layer 50b is coated on the surface of the second graphene film 40b, and the stacking of the graphene film and silicone layer is repeated to obtain a transverse graphene film and silicone layer stack 60A; The transverse graphene film and silicone layer stack 60A are cured to form a transverse graphene film and silicone composite material block 60B; 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; The stacked slice 70A was flipped 90 degrees and laid flat. The top and bottom surfaces of the stacked slice 70A are de-adhesive-removed to form a hollow section 51; and 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.

[0042] 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.

[0043] More importantly, its effects are as follows Figure 14AThe 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. The vertical multi-layered graphene heat-conducting sheet 70B of this invention has resilience, meaning it is compressible. When pressure (P) is applied, it has resistance to compression. When the height (H1) is compressed to (H2), it has an elastic buffering force that resists compression and can release a reverse elasticity. This characteristic is indeed necessary and has substantial benefits in practical applications of heat dissipation products, as explained below.

[0044] Figure 14B The diagram shows a usage state of the present invention, illustrating the application of a vertical multilayer graphene thermal conductive sheet 70B with a thickness of 0.15mm to 5mm in an electronic device 10. By placing this vertical multilayer graphene thermal conductive sheet 70B between the electronic component (e.g., a semiconductor chip) 12 and the heat sink 13, the flexibility and resilience of the sheet allow it to fill the gap between the electronic component 12 and the heat sink 13, thereby reducing the thermal resistance between them and ensuring that the electronic device 10 operates at its normal operating temperature. This improves the stability and lifespan of the electronic device. Furthermore, the vertical multilayer graphene thermal conductive sheet 70B provides elastic cushioning, preventing damage to the electronic component 12 from the pressure of the heat sink 13. Therefore, the advantages of the vertical multilayer graphene thermal conductive sheet (LGS) 70B prepared by the present invention include: 1. No liquid metal leakage protection is required for the module. 2. Easy to install; the product can be directly attached to the CPU. 3. High reliability and weather resistance; not easily oxidized. 4. Soft material; does not easily expand and press against the module. 5. Possesses a certain structural strength; not prone to localized material shortages at the interface after long-term use.

[0045] Figure 15A The diagram shows the thermal conductivity of a typical graphene film in the transverse (XY) and longitudinal (Z) directions. Conventional graphene 30 has a transverse (XY) thermal conductivity of up to 1500 W / mK, but its longitudinal (Z) thermal conductivity is only 15 W / mK. Therefore, this invention utilizes the transverse thermal conductivity of graphene and employs a pre-coating method to transform the transverse (XY) direction into the longitudinal direction, resulting in a vertical multilayer graphene thermal conductive sheet (LGS) 70B, whose thermal conductivity characteristics are as follows... Figure 15B As indicated by the arrow, high thermal conductivity can be achieved in the longitudinal direction, and the structure of the heat-conducting sheet remains stable under pressure and rebound.

[0046] Based on the above technical features, the vertical multi-layer graphene thermal conductive sheet (LGS) 70B prepared by this invention is a composite material of artificial graphene and silicon (silicone) adhesive. The product has the characteristics of high thermal conductivity, low contact thermal resistance, high compression, and resistance to high and low temperatures. It 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 at the same time plays a role in shock absorption and impact protection.

[0047] 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: I. The vertical multi-layered graphene thermal conductive sheet 70B prepared by this invention involves first drilling holes in each graphene film 40 using a laser at the beginning of the manufacturing process. This allows the silicone in the process to penetrate into each hole 41, forming a plurality of holes 41. This enables the graphene films 40 to connect with each other, creating a completely continuous structure between the polymers. Not only does it exhibit 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 invention 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 locking process of operating electronic devices; Third, the vertical multi-layer graphene thermal conductive sheet 70B prepared by the present invention has graphene fibers 71 evenly distributed between each graphene film 40, with consistent thermal conductivity, and can conduct heat along the longitudinal direction, thereby avoiding heat accumulation caused by heat conduction along the transverse direction.

[0048] The above-disclosed figures and descriptions are merely preferred embodiments of the present invention. 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 method for preparing a multi-layered graphene thermal conductive sheet with strong bonding and resilience, characterized in that, include: Step S01: Provide a plurality of graphene films, and first use a laser to drill holes in each graphene film to form a plurality of holes with a diameter of 0.1mm to 1mm. The diameter of the holes and the surface area they occupy are set according to the required bonding strength and resilience of the graphene film. Step S02: Irradiate the perforated graphene film with an ultraviolet lamp for 1-2 minutes to generate hydrophilic functional groups on the surface of the graphene film; Step S03: Coat a first silicone layer onto the surface of a first graphene film; Step S04: Place a second graphene film on the first silicone layer; Step S05: Allow a portion of the first silicone layer to penetrate into the pores of the first and second graphene films; Step S06: Coat the surface of the second graphene film with a second silicone layer; repeat steps S04 and S05 above to obtain a transverse graphene film and silicone layer stack. Step S07: The lateral graphene film and silicone layer stack is cured to form a lateral graphene film and silicone composite material block; Step S08: Along the direction of stack thickness, vertically cut the transverse graphene film and silicone composite material block at intervals of 0.15mm to 5mm to form numerous stacked slices; Step S09: Flip the stacked slices 90 degrees and lay them flat; Step S10: Remove the adhesive from the top and bottom surfaces of the stacked slices to form a hollow section; Step S11: Graphene fiber filling is performed at the hollowed-out area so that the graphene films can be interconnected to form a vertical multi-layered graphene heat-conducting sheet with a thickness of 0.15mm to 5mm, strong bonding force and resilience.

2. The method for preparing a multi-layered graphene thermal conductive sheet with strong bonding and resilience according to claim 1, wherein, In step S01, the graphene film has a thickness of 10μm to 100μm, a length of 5cm to 30cm or in roll form, and a width of 5cm to 30cm; the silicone coating has a thickness of 0.01mm to 0.1mm, a length of 5cm to 30cm, and a width of 5cm to 30cm.

3. The method for preparing a multi-layered graphene thermal conductive sheet with strong bonding and resilience according to claim 1, wherein, In step S06, the thickness of the graphene film and the silicone layer stack is 5cm to 30cm.

4. The method for preparing a multi-layered graphene thermal conductive sheet with strong bonding and resilience according to claim 1, wherein, In step S10, the stacked slices undergo a desmearing process, which includes removing the silicone from the upper and lower end faces using a laser or a solvent.

5. The method for preparing a multi-layered graphene thermal conductive sheet with strong bonding and resilience according to claim 1, wherein, In step S11, the graphene fiber filling operation performed at the hollow portion includes grinding or ultrasonic processing of the surface of the stacked slices to form numerous graphene fibers in the hollow portion.

6. A multi-layered graphene thermal conductive sheet with strong bonding and resilience, prepared by the preparation method of claims 1 to 5, comprising: Most graphene films and silicone films have numerous pores with diameters ranging from 0.1 mm to 1 μm formed on the graphene film, and hydrophilic functional groups are generated on the surface of the graphene film; A first silicone layer is coated on the surface of a first graphene film, and a second graphene film is placed on the first silicone layer; a portion of the first silicone layer permeates into the pores of both the first and second graphene films. Next, a second silicone layer is coated on the surface of the second graphene film, and the stacking of the graphene film and silicone layer is repeated to obtain a transverse graphene film and silicone layer stack. The transverse graphene film and silicone layer stack were cured to form a transverse graphene film and silicone composite material block; Along the direction of the stacked thickness, the transverse graphene film and silicone composite block are vertically cut at intervals of 0.15mm to 5mm to form numerous stacked slices; these stacked slices are then flipped 90 degrees and laid flat. The top and bottom surfaces of the stacked slices are de-adhesive-removed to form a hollow portion; and graphene fibers are filled in the hollow portion so that the graphene films between the stacked slices can be interconnected to form a vertical multi-layered graphene thermal conductive sheet with a thickness of 0.15mm to 5mm and strong bonding and resilience.

7. The flexible multi-layered graphene thermal conductive sheet according to claim 6, wherein, The graphene film has a thickness of 10μm to 100μm, a length of 5cm to 30cm or in roll form, and a width of 5cm to 30cm. The silicone coating has a thickness of 0.01mm to 0.1mm, a length of 5cm to 30cm, and a width of 5cm to 30cm.

8. The multi-layered graphene thermal conductive sheet with strong bonding and resilience according to claim 7, wherein, The thickness of the horizontal graphene film and silicone layer stack is 5cm to 30cm.

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