Thermally conductive pad and preparation method therefor, electronic component and electronic device

Abstract

Embodiments of the present application relate to the technical field of thermal interface materials. Provided are a thermally conductive pad and a preparation method therefor, an electronic component, and an electronic device. The thermally conductive pad comprises graphene film groups, graphene foam film groups, and adhesive members, and the graphene foam film groups and the graphene film groups are alternately arranged in a direction perpendicular to the thickness direction of the thermally conductive pad. Each adhesive member is at least located between the graphene film group and the graphene foam film group that are adjacent to each other, and the graphene film group and the graphene foam film group that are adjacent to each other are bonded and connected by means of the adhesive member. The adhesive member comprises an adhesive matrix and a wave-absorbing filler which are mixed with each other, the adhesive matrix being used for providing bonding performance, and the wave-absorbing filler being used for absorbing waves. The thermally conductive pad provided in the present application can effectively reduce the compressive stress of the thermally conductive pad, can effectively improve the thermal conductivity of the thermally conductive pad, reduce the thermal resistance of the thermally conductive pad, and can also effectively improve the wave absorption performance of the thermally conductive pad, thereby effectively reducing electromagnetic interference between various electronic components in an electronic device.

Description

Thermal pads and their preparation methods, electronic devices and electronic equipment

[0001] This application claims priority to Chinese Patent Application No. 202510068462.5, filed on January 15, 2025, entitled "Thermal Conductive Pad and Method for Preparation Thereof, Electronic Device and Electronic Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of thermal interface materials technology, and in particular to a thermally conductive pad and its preparation method, electronic devices, and electronic equipment. Background Technology

[0003] Thermal pads are thermal interface materials used to improve thermal management and are widely used in various electronic devices and components requiring effective heat dissipation. With the increasing power, miniaturization, and integration of electronic devices, the operating power of these devices is rising, leading to more severe heat dissipation and electromagnetic interference problems. Therefore, higher requirements are placed on the thermal conductivity, compressive stress, and electromagnetic interference resistance of thermal interface materials.

[0004] Typically, thermally conductive pads are prepared by mixing thermally conductive fillers, microwave-absorbing fillers, and a resin matrix. However, thermally conductive pads with good microwave absorption and thermal conductivity require the simultaneous addition of a significant amount of both thermally conductive and microwave-absorbing fillers. Due to compatibility issues between the resin matrix and the inorganic fillers (i.e., thermally conductive and microwave-absorbing fillers), these fillers are often not added in large quantities simultaneously. Furthermore, achieving good dispersion is difficult, and the thermally conductive pads often have high hardness and high compressive stress. Consequently, the thermal conductivity, microwave absorption, and compressive stress performance of the resulting thermally conductive pads do not meet the desired requirements. Summary of the Invention

[0005] This application provides a thermally conductive pad and its preparation method, as well as electronic devices and electronic equipment, which can effectively improve the thermal conductivity and wave absorption performance of the thermally conductive pad and reduce compressive stress.

[0006] The first aspect of this application provides a thermally conductive pad, comprising:

[0007] One or more graphene film modules;

[0008] One or more graphene foam film groups, wherein the one or more graphene foam film groups are stacked and alternately arranged with the one or more graphene film groups along a first direction, the first direction being perpendicular to the thickness direction of the thermal pad;

[0009] The density of each graphene foam film assembly is less than the density of each graphene film assembly;

[0010] An adhesive element is located at least between two adjacent graphene film groups and graphene foam film groups, and the two adjacent graphene film groups and graphene foam film groups are bonded together by the adhesive element.

[0011] Each of these adhesive components comprises an adhesive matrix and a microwave-absorbing filler mixed together, the adhesive matrix being used to provide adhesive properties and the microwave-absorbing filler being used to absorb microwaves.

[0012] This application describes a thermal pad comprising alternating layers of graphene film and graphene foam film, bonded together by an adhesive containing microwave-absorbing filler. The graphene foam film has a low density and porous structure, effectively reducing compressive stress and facilitating compression of the thermal pad. The high density of the graphene film provides high hardness and support, as well as low thermal resistance and high thermal conductivity, effectively improving the thermal conductivity and reducing the thermal resistance of the thermal pad, thus enhancing heat dissipation for electronic devices. Furthermore, the addition of microwave-absorbing filler to the adhesive provides microwave absorption while maintaining bonding performance, effectively improving the microwave absorption of the thermal pad and reducing electromagnetic interference between electronic components in the electrical appliance.

[0013] In one possible implementation, each graphene film assembly includes one or more graphene films stacked along the first direction; the adhesive is also located between two adjacent graphene films, which are bonded together by the adhesive.

[0014] This can effectively improve the strength and reliability of the connection between two adjacent graphene films, effectively reduce or avoid separation between the two graphene films, and help improve the structural stability of the thermal pad.

[0015] Furthermore, each graphene film assembly incorporates adhesive components, which effectively increases the amount of adhesive components in the thermal pad and consequently the amount of microwave-absorbing filler, thereby enhancing the microwave absorption performance of the thermal pad. In addition, the adhesive matrix within the adhesive components exhibits low compressive stress, effectively reducing the overall compressive stress of the thermal pad.

[0016] In one possible implementation, each graphene foam film assembly includes one or more graphene foam films stacked along the first direction; the adhesive is also located between two adjacent graphene foam films, which are bonded together by the adhesive.

[0017] This effectively improves the strength and reliability of the connection between two adjacent graphene foam films, and can effectively reduce or avoid separation between the two graphene foam films, thereby effectively improving the structural stability of the thermal pad.

[0018] Furthermore, adhesive components are incorporated into each graphene foam film assembly, effectively increasing the amount of adhesive components in the thermally conductive pad. This, in turn, increases the amount of microwave-absorbing filler in the thermally conductive pad, thereby enhancing its microwave absorption performance. In addition, the adhesive matrix within the adhesive components exhibits low compressive stress, effectively reducing the overall compressive stress of the thermally conductive pad.

[0019] In one possible implementation, the thermal pad is further provided with a through groove that extends through the thermal pad along the first direction; the adhesive is also filled in the through groove.

[0020] The adhesive components within the through-slot can also achieve a microwave absorption effect, effectively increasing the amount of adhesive components in the thermal pad and thus improving its microwave absorption performance. Furthermore, by extending the through-slot through the thermal pad in the first direction, the distribution of adhesive components within the thermal pad can be effectively increased, thereby further enhancing its microwave absorption performance.

[0021] In one possible implementation, there are multiple through-slots, which are spaced apart along a second direction perpendicular to the thickness direction of the thermal pad and the first direction. This effectively increases the amount of adhesive in the thermal pad, thereby improving its microwave absorption performance.

[0022] In one possible implementation, the number of graphene films in each graphene film group is 1 to 3. This improves the rationality of the graphene film content, avoiding an insufficient number of graphene films that would affect the thermal conductivity and thermal resistance of the thermal pad, thus impacting its heat dissipation performance. It effectively improves the thermal conductivity and reduces the thermal resistance of the thermal pad. Furthermore, it avoids an excessive number of graphene films that would increase the support of the thermal pad, thereby affecting its compressive stress and helping to reduce it. This allows the thermal conductivity, thermal resistance, and compressive stress of the thermal pad to be at a more reasonable level.

[0023] In one possible implementation, the graphene film thickness is 50 μm to 150 μm. This thickness effectively improves the rationality of the graphene film thickness. It avoids the problem of excessive graphene film thickness increasing the support and compressive stress of the thermal pad, thus effectively reducing the compressive stress of the thermal pad. Furthermore, it avoids the problem of insufficient graphene film thickness affecting the thermal conductivity and thermal resistance of the thermal pad, thereby impacting its heat dissipation performance. This effectively improves the thermal conductivity and reduces the thermal resistance of the thermal pad. Ultimately, it achieves high thermal conductivity and low thermal resistance while effectively reducing the support of the graphene film and increasing the compressive stress of the thermal pad.

[0024] In one possible implementation, the in-plane thermal conductivity of the graphene film is greater than 1000 W / (mK). This can effectively reduce the thermal resistance of the graphene film assembly and increase its thermal conductivity, thereby effectively improving the thermal conductivity and heat dissipation effect of the thermal pad.

[0025] In one possible implementation, the number of graphene foam films in each graphene foam film group is 1 to 15, and the ratio of the number of graphene films to the number of graphene foam films in two adjacent graphene film groups and in the graphene foam film group is 1:1 to 1:5.

[0026] This approach improves the appropriateness of the graphene foam film content and enhances the proportional coordination between the graphene foam film and the graphene film. It avoids insufficient graphene foam film, which could negatively impact the compressive stress of the thermal pad, thus helping to reduce it. Furthermore, it prevents excessive graphene foam film, which could negatively affect the thermal conductivity and thermal resistance of the thermal pad, thereby affecting its heat dissipation performance. This effectively improves the thermal conductivity and reduces the thermal resistance of the thermal pad, enhancing the proportional coordination between the graphene foam film and the graphene film. Ultimately, it ensures that the thermal conductivity, thermal resistance, and compressive stress of the thermal pad are at a more reasonable level.

[0027] In one possible implementation, the thickness of the graphene foam film is 300 μm to 800 μm. This thickness effectively improves the reasonableness of the graphene foam film thickness. It avoids the graphene foam film being too thick, which would affect the thermal conductivity and thermal resistance of the thermal pad, and thus affect the heat dissipation effect of the thermal pad. It can effectively improve the thermal conductivity of the thermal pad and reduce its thermal resistance. Moreover, it can also avoid the graphene foam film being too thin, which would affect the compressive stress of the thermal pad, and helps to reduce the compressive stress of the thermal pad. This allows the thermal pad to effectively improve its thermal conductivity and reduce its thermal resistance while achieving low compressive stress.

[0028] In one possible implementation, the graphene foam film has an in-plane thermal conductivity greater than 100 W / (mK). The low in-plane thermal conductivity of the graphene foam film, coupled with its numerous internal pores, effectively reduces the compressive stress of the graphene foam film, thereby effectively improving the compressive stress of the thermally conductive pad.

[0029] In one possible implementation, the molding material of the adhesive matrix includes at least one of liquid silicone, neoprene rubber, acrylic resin, epoxy resin, polyurethane, polyethylene, polypropylene, phenolic resin, polyvinyl butyral, or ethylene-acetic acid copolymer. These materials all possess good adhesive properties, providing a good bond between graphene foam film modules and graphene film modules, effectively reducing or preventing separation between them, and significantly improving the strength and reliability of the connection between the graphene foam film modules and graphene film modules, thereby enhancing the structural stability of the thermal pad.

[0030] In one possible implementation, the molding material for the adhesive substrate is liquid silicone. Liquid silicone has good resistance to high and low temperatures, maintaining its physical adhesive properties at high temperatures and effectively improving the stability of the bonded components, thus providing better adhesion in thermal pads. Furthermore, liquid silicone has good electrical insulation properties, enabling the thermal pads to have good insulating properties, thereby providing better insulating protection in the encapsulation of electronic devices.

[0031] In one possible implementation, the viscosity of the liquid silicone is 50 mPa·s to 3000 mPa·s. This viscosity allows the adhesive to have high bonding performance, enabling it to achieve a good bonding effect in the thermal pad. This effectively reduces or avoids separation between graphene foam film modules and graphene film modules, effectively improving the strength and reliability of the connection between them, thereby enhancing the structural stability of the thermal pad.

[0032] In one possible implementation, the microwave absorbing filler material includes at least one of ferrite, barium titanate, metal micropowder, graphite, or ceramic. These materials all possess good electrical conductivity and can effectively absorb electromagnetic waves, thus giving the thermal pad good microwave absorption performance.

[0033] In one possible implementation, the microwave-absorbing filler material is ferrite or metal micropowder. Ferrite is a magnetic material with good magnetic permeability and resistivity, which can effectively absorb electromagnetic waves and improve the microwave absorption performance of the thermal pad. Metal micropowder has high electrical conductivity and magnetic permeability, which can effectively absorb electromagnetic waves and improve the microwave absorption performance of the thermal pad. Furthermore, the metal micropowder can be uniformly mixed with the adhesive matrix, allowing the microwave-absorbing filler to be evenly distributed in the adhesive matrix, which helps to improve the microwave absorption performance of the bonded component.

[0034] In one possible implementation, the microwave absorbing filler is made of flake-shaped iron-silicon-aluminum powder from metal micropowder. The flake-shaped iron-silicon-aluminum powder has good magnetic permeability, giving the microwave absorbing filler a good microwave absorption effect. This allows the adhesive to effectively absorb energy in the magnetic field portion of electromagnetic waves, thus significantly improving the microwave absorption performance of the adhesive.

[0035] In one possible implementation, the particle size of the flake-shaped iron-silicon-aluminum powder is 200 nm to 500 μm. Particles of different sizes can exhibit different absorption characteristics in different frequency ranges. Smaller nanoparticles generally exhibit better absorption performance in high-frequency bands (such as microwave bands), while larger micron-sized particles may be more effective in lower-frequency bands (such as radio frequency bands). By setting the particle size of the flake-shaped iron-silicon-aluminum powder to the above values, the absorption frequency range of the microwave absorbing material can be effectively increased. Moreover, the above dimensions allow for better overlap of the flake-shaped iron-silicon-aluminum powder, which helps to improve the overall microwave absorption performance of the bonded component.

[0036] In one possible implementation, the microwave-absorbing filler comprises 5% to 50% by weight in the adhesive component. This ratio improves the reasonableness of the filler content in the adhesive component, preventing insufficient filler content from affecting the microwave absorption and energy absorption of the adhesive component, thus effectively improving its microwave absorption and energy absorption. It also prevents excessive filler content from affecting the adhesive performance, ensuring that the adhesive performance is effectively improved while meeting microwave absorption requirements. This results in better adhesion of the adhesive component in the thermal pad, thereby enhancing the structural stability of the thermal pad.

[0037] In one possible implementation, the thermal pad also has a through-hole that extends through the thermal pad along the first direction; the adhesive further fills the through-hole. The adhesive within the through-hole can also achieve a microwave absorption effect, thus effectively increasing the amount of adhesive in the thermal pad and improving its microwave absorption performance. Moreover, by making the through-hole extend through the thermal pad along the first direction, the distribution of adhesive in the thermal pad can be effectively increased, thereby effectively improving the microwave absorption performance of the thermal pad.

[0038] In one possible implementation, the number of through holes is multiple, and these through holes are spaced apart along a second direction, which is perpendicular to the thickness direction of the thermal pad and the first direction. This can effectively increase the amount of adhesive in the thermal pad, thereby effectively improving the microwave absorption performance of the thermal pad.

[0039] In one possible implementation, the cross-sectional shape of the through-hole includes rectangular or circular. These shapes facilitate the machining of the through-hole, reducing machining costs. Furthermore, the aforementioned cross-sectional shape allows for the inclusion of more adhesive within the through-hole, increasing the amount of adhesive within the thermal pad and enhancing its microwave absorption performance.

[0040] In one possible implementation, the maximum cross-sectional size of the through-hole is 0.1mm to 0.5mm. This effectively improves the rationality of the through-hole cross-sectional size, preventing excessively large through-holes from affecting the content of graphene film and graphene foam film, thereby impacting the thermal conductivity and compressive stress of the thermal pad. Furthermore, it avoids excessively small through-hole cross-sectional sizes, which could affect the content of adhesive components in the thermal pad and thus its microwave absorption effect, thereby effectively improving the microwave absorption performance of the thermal pad.

[0041] In one possible implementation, the distance between two adjacent through-slots is 0.2mm to 5mm. This value improves the rationality of the through-slot distribution in the thermal pad, preventing excessively large distances between slots from reducing the content of adhesive components and thus affecting the pad's microwave absorption effect, thereby contributing to improved microwave absorption performance. It also prevents excessively small distances between slots from affecting the content of graphene film and graphene foam film in the thermal pad, which in turn affects the thermal conductivity and compressive stress of the thermal pad, effectively improving both.

[0042] In one possible implementation, the width of the cross-section of the channel is 0.1mm to 0.5mm. This value avoids the channel width being too large, which would affect the content of graphene film and graphene foam film in the thermal pad, and also avoids the channel width being too small, which would affect the content of adhesive components in the thermal pad. This effectively improves the rationality of the channel distribution in the thermal pad and the rationality of the adhesive component content. While meeting the microwave absorption performance requirements of the thermal pad, it effectively improves the thermal conductivity and compressive stress of the thermal pad.

[0043] In one possible implementation, the thickness of the thermal pad is 0.2mm to 2mm. This thickness avoids excessive thickness, which could affect the thermal conductivity and increase the thermal resistance of the thermal pad. It also prevents excessive thickness from increasing the space occupied by the thermal pad in electronic components, thus improving the internal spatial layout of the components. Furthermore, it avoids the thermal pad being too small, which could lead to poor contact and affect its thermal conductivity and compressive stress. This allows the thermal pad to effectively reduce its space occupation while meeting the requirements for thermal conductivity, thermal resistance, and compressive stress, thereby improving the rationality of its placement within electronic components.

[0044] A second aspect of this application provides an electronic device including a power device and a thermal pad as described above, the thermal pad covering the power device.

[0045] A third aspect of this application provides an electronic device including the aforementioned electronic components.

[0046] A fourth aspect of this application provides a method for preparing a thermally conductive pad, used to prepare any of the above-mentioned thermally conductive pads, the method comprising:

[0047] The graphene film and graphene foam film are cut into the same shape and size;

[0048] The adhesive is prepared by mixing microwave absorbing filler and adhesive matrix;

[0049] An adhesive is coated on the first graphene foam film, and the adhesive is stacked with the graphene foam film in a first direction, which is the thickness direction of the graphene foam film.

[0050] A second graphene foam film is stacked on the adhesive along the first direction, and this process is repeated to form a graphene foam film assembly.

[0051] The adhesive is coated on the last graphene foam film in the graphene foam film assembly, so that the adhesive and the graphene foam film are stacked in a first direction, and the first graphene film is stacked on the adhesive along the first direction.

[0052] The first graphene film is coated with the adhesive, and the adhesive and the graphene film are stacked in a first direction. A second graphene film is then stacked on the adhesive along the first direction, and this process is repeated to form a graphene film assembly.

[0053] The graphene foam film assembly is then prepared again on the graphene film assembly, and the graphene film assembly is prepared again on the graphene foam film assembly. This process is repeated to obtain a thermal pad blank of a predetermined thickness.

[0054] The thermal pad blank is then heated and cured.

[0055] The thermal pad blank is cut along a plane perpendicular to a third direction to obtain a pad blank. The third direction is perpendicular to the first direction and is the thickness direction of the pad blank.

[0056] The gasket blank was treated in a silicone cleaning agent;

[0057] The gasket preform was ultrasonically treated in ethanol;

[0058] The gasket blank is dried to obtain a thermally conductive gasket.

[0059] In one possible implementation, the thermal pad is further provided with a through hole that extends through the thermal pad along the first direction, and the adhesive is further filled in the through hole;

[0060] Prior to coating the adhesive onto the first graphene foam film, the preparation method further includes:

[0061] Through holes of the same size and arrangement are formed on the graphene film and the graphene foam film;

[0062] When the adhesive is coated onto the graphene film and the graphene foam film, it also fills the through-holes in the graphene film and the graphene foam film. Attached Figure Description

[0063] Figure 1 is a schematic diagram of the structure of a thermally conductive pad provided in an embodiment of this application;

[0064] Figure 2 is a side view of a thermally conductive pad provided in an embodiment of this application;

[0065] Figure 3 is a left view of a thermally conductive pad provided in an embodiment of this application;

[0066] Figure 4 is a front view of a thermal pad provided in an embodiment of this application at a first magnification.

[0067] Figure 5 is a front view of a thermal pad provided in an embodiment of this application at a second magnification.

[0068] Figure 6 is a front view of a thermal pad provided in an embodiment of this application at the third magnification.

[0069] Figure 7 is a front view of a thermal pad provided in an embodiment of this application at the fourth magnification.

[0070] Figure 8 is a left view of another thermally conductive pad provided in an embodiment of this application;

[0071] Figure 9 is a schematic flowchart of a method for preparing a thermal pad according to an embodiment of this application;

[0072] Figure 10 is a schematic diagram of the structure of a thermal pad blank provided in an embodiment of this application;

[0073] Figure 11 is a schematic diagram of the structure of a thermally conductive pad provided in an embodiment of this application;

[0074] Figure 12 is a schematic diagram of a rectangular through hole provided in this application;

[0075] Figure 13 is a schematic diagram of a circular through hole provided in an embodiment of this application;

[0076] Figure 14 shows the compressive stress-strain curves of graphene film / foam laminates with different ratios provided in Embodiments 1, 2, and 3 of this application.

[0077] Figure 15 shows the microwave absorption isolation test results of a thermally conductive pad provided in Embodiment 2 of this application;

[0078] Figure 16 shows the microwave absorption isolation test results of a thermally conductive pad provided in Embodiment 3 of this application.

[0079] Explanation of reference numerals in the attached drawings: 100 - Thermal pad; 110 - Graphene film assembly; 111 - Graphene film; 120 - Graphene foam film assembly; 121 - Graphene foam film; 130 - Adhesive component; 140 - Through groove; 150 - Through hole. Detailed Implementation

[0080] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0081] Thermal pads are thermal interface materials used to improve thermal management and are widely used in various electronic devices and components requiring effective heat dissipation. With the increasing power, miniaturization, and integration of electronic devices, the operating power of these devices is rising, leading to more severe heat dissipation and electromagnetic interference problems. Therefore, higher requirements are placed on the thermal conductivity, compressive stress, and electromagnetic interference resistance of thermal interface materials.

[0082] Typically, in related technologies, thermally conductive pads are prepared by mixing thermally conductive fillers with a resin matrix. However, such thermally conductive pads have low thermal conductivity, high compressive stress, and poor resilience, failing to meet the low compressive stress requirement for thermally conductive pads.

[0083] In another related technology, thermally conductive fillers and microwave-absorbing fillers are used in combination. The mixture of these two fillers is then mixed with a resin matrix to prepare a thermally conductive pad with both thermal conductivity and microwave absorption properties. However, achieving good thermal conductivity and microwave absorption properties requires the simultaneous addition of large amounts of both thermally conductive and microwave-absorbing fillers. Due to compatibility issues between the resin matrix and the inorganic fillers (i.e., thermally conductive and microwave-absorbing fillers), these fillers are often not added in large quantities simultaneously. Furthermore, achieving good dispersion is difficult, resulting in thermally conductive pads whose thermal conductivity and microwave absorption properties do not meet ideal requirements. Additionally, these thermally conductive pads often have high hardness and poor mechanical properties.

[0084] To address the aforementioned issues, this application provides a thermally conductive pad, an electronic device including the thermally conductive pad, and an electronic device including the electronic device. The thermally conductive pad comprises alternating layers of graphene film and graphene foam film, and the graphene film and graphene foam film are bonded together using an adhesive containing microwave-absorbing filler. The graphene foam film has a low density and internal pores, effectively reducing the compressive stress of the thermally conductive pad and facilitating its compression. The graphene film has a high density, providing high hardness and support, as well as low thermal resistance and high thermal conductivity, effectively improving the thermal conductivity and reducing the thermal resistance of the thermally conductive pad, thereby significantly enhancing heat dissipation during electronic operation. Furthermore, by adding microwave-absorbing filler to the adhesive, the adhesive not only meets bonding performance requirements but also possesses microwave-absorbing properties. It can effectively improve the wave absorption performance of thermal pads, thereby effectively reducing electromagnetic interference between various electronic components in electrical appliances.

[0085] The thermally conductive pads provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0086] Figure 1 is a schematic diagram of a thermal pad provided in an embodiment of this application, and Figure 2 is a side view of a thermal pad provided in an embodiment of this application.

[0087] This application provides a thermally conductive pad 100, which can be applied to the thermal interface material of electronic device packaging. For example, the electronic device may include a power device, and the thermally conductive pad 100 can cover the power device. During operation, the power device may generate heat, and this heat can be transferred outward through the thermally conductive pad 100 to achieve heat dissipation and cooling of the power device.

[0088] Referring to Figures 1 and 2, the thermal pad 100 may include one or more graphene film assemblies 110 and one or more graphene foam film assemblies 120. The one or more graphene film assemblies 110 and the one or more graphene foam film assemblies 120 may be stacked and alternately arranged along a first direction (i.e., the x-direction in Figure 1). The first direction refers to the direction perpendicular to the thickness direction of the thermal pad 100; for example, the thickness direction of the thermal pad 100 may be the z-direction in Figure 1.

[0089] For example, in the first direction, a graphene film group 110 can be set first, then a graphene foam film group 120 can be set on the graphene film group 110, and then another graphene film group 110 can be set on the graphene foam film group 120, and so on, to form a structure in which the graphene film group 110 and the graphene foam film group 120 are alternately set.

[0090] The density of each graphene foam film assembly 120 can be lower than that of each graphene film assembly 110. For example, the graphene foam film assembly 120 may contain pores, which can reduce the weight of the graphene foam film assembly 120 per unit volume, thereby reducing the density of the graphene foam film assembly 120. Because of the pores within it, the graphene foam film assembly 120 has lower compressive stress. By arranging the graphene foam film assembly 120 along a direction perpendicular to the thickness of the thermal pad 100, the thermal pad 100 can have lower compressive stress, thus facilitating the compression of the thermal pad 100.

[0091] The graphene film 110 has a relatively high density and hardness, providing good support. Furthermore, its high density also contributes to its good thermal conductivity. By arranging the graphene film 110 along a direction perpendicular to the thickness of the thermal pad 100, the support and thermal conductivity of the thermal pad 100 can be improved, while reducing its thermal resistance.

[0092] The thermal pad 100 may also include an adhesive 130, which may be located at least between two adjacent graphene film groups 110 and graphene foam film groups 120, and the two adjacent graphene film groups 110 and graphene foam film groups 120 may be bonded together by the adhesive 130.

[0093] Each adhesive component 130 may include an adhesive matrix and a microwave absorbing filler that are mixed together. For example, the adhesive matrix and the microwave absorbing filler may be mixed and stirred to ensure thorough mixing and uniform distribution of the microwave absorbing filler within the adhesive matrix. Alternatively, the adhesive matrix and the microwave absorbing filler may be placed in a planetary mixer and stirred at a speed of 500-1000 rpm to ensure thorough mixing and effectively improve the uniformity and consistency of the microwave absorbing filler distribution within the adhesive matrix.

[0094] The adhesive matrix can be used to provide adhesion between the graphene film assembly 110 and the graphene foam film assembly 120, thereby reducing or preventing separation between them. The microwave absorbing filler can be used to absorb microwaves, effectively improving the microwave absorption performance of the thermal pad 100, thus effectively reducing electromagnetic interference between various electronic components in the electrical appliance.

[0095] This embodiment of the application includes a thermal pad 100 comprising alternating layers of graphene film 110 and graphene foam film 120, with the graphene film 110 and graphene foam film 120 bonded together by an adhesive 130 mixed with microwave-absorbing filler. The graphene foam film 120 has a low density and internal pores, effectively reducing the compressive stress of the thermal pad 100, thus facilitating its compression. The graphene film 110 has a high density, giving it high hardness and support, as well as low thermal resistance and high thermal conductivity, effectively improving the thermal conductivity and reducing the thermal resistance of the thermal pad 100, thereby significantly enhancing heat dissipation during electron transport. Furthermore, by adding microwave-absorbing filler to the adhesive 130, the adhesive 130 not only meets the bonding performance requirements but also possesses microwave-absorbing properties. It can effectively improve the wave absorption performance of the thermal pad 100, thereby effectively reducing electromagnetic interference between various electronic components in electrical appliances.

[0096] Referring again to Figures 1 and 2, each graphene film assembly 110 may include one or more graphene films 111 stacked along a first direction. An adhesive 130 may also be located between two adjacent graphene films 111, allowing them to be bonded together. This effectively improves the strength and reliability of the connection between adjacent graphene films 111, effectively reducing or preventing separation between the two graphene films 111, and contributing to improved structural stability of the thermal pad 100.

[0097] Furthermore, each graphene film assembly 110 includes an adhesive element 130, which effectively increases the content of the adhesive element 130 in the thermal pad 100, thereby increasing the content of the microwave-absorbing filler in the thermal pad 100 and thus effectively improving the microwave absorption performance of the thermal pad 100. In addition, the adhesive matrix in the adhesive element 130 has low compressive stress, which effectively reduces the overall compressive stress of the thermal pad 100.

[0098] Referring again to Figures 1 and 2, each graphene foam film assembly 120 may include one or more graphene foam films 121 stacked along a first direction. An adhesive 130 may also be located between two adjacent graphene foam films 121, allowing them to be bonded together. This effectively improves the strength and reliability of the connection between adjacent graphene foam films 121, effectively reducing or preventing separation between the two graphene foam films 121, thereby effectively improving the structural stability of the thermal pad 100.

[0099] Furthermore, each graphene foam film assembly 120 includes an adhesive component 130, which effectively increases the content of the adhesive component 130 in the thermally conductive pad 100, thereby increasing the content of the microwave-absorbing filler in the thermally conductive pad 100 and thus effectively improving the microwave absorption performance of the thermally conductive pad 100. In addition, the adhesive matrix in the adhesive component 130 has low compressive stress, which can effectively reduce the overall compressive stress of the thermally conductive pad 100.

[0100] Figure 3 is a left view of a thermally conductive pad provided in an embodiment of this application; Figure 4 is a front view of a thermally conductive pad provided in an embodiment of this application at a first magnification; Figure 5 is a front view of a thermally conductive pad provided in an embodiment of this application at a second magnification; Figure 6 is a front view of a thermally conductive pad provided in an embodiment of this application at a third magnification; and Figure 7 is a front view of a thermally conductive pad provided in an embodiment of this application at a fourth magnification. The coordinate system in Figures 4, 5, 6, and 7 is the same as that in Figure 1.

[0101] Referring to Figure 3, a through groove 140 can also be formed on the thermal pad 100. As shown in Figures 4 and 5, the through groove 140 extends through the thermal pad 100 along a first direction, meaning the extension direction of the through groove 140 is the same as the stacking direction of the graphene film assembly 110 and the graphene foam film assembly 120. In other words, the through groove 140 can be understood as being formed on the side of the thermal pad 100 and extending along the length or width of the thermal pad 100. The adhesive 130 can also be filled within the through groove 140. The adhesive 130 within the through groove 140 can also achieve a wave-absorbing effect, thus effectively increasing the content of the adhesive 130 in the thermal pad 100 and effectively improving the wave-absorbing performance of the thermal pad 100. Furthermore, by making the through groove 140 penetrate the thermal pad 100 along the first direction, the distribution of the adhesive 130 in the thermal pad 100 can be effectively increased, thereby effectively improving the wave absorption performance of the thermal pad 100.

[0102] The through groove 140 may not penetrate the thickness direction of the thermal pad 100 (i.e., the z-direction in Figure 1). Alternatively, the through groove 140 may penetrate the thickness direction of the thermal pad 100.

[0103] Preferably, the through groove 140 can extend through the thickness direction of the thermal pad 100, so that the adhesive 130 in the through groove 140 can provide a better wave absorption effect in the thickness direction of the thermal pad 100, which can effectively improve the wave absorption performance of the thermal pad 100.

[0104] As shown in Figures 4 to 7, the through groove 140 extends through the thickness direction of the thermal pad 100, and the through groove 140 can be presented on the surface of the thermal pad 100, and the adhesive 130 within the through groove 140 can be presented.

[0105] Referring again to Figure 3, there can be multiple through-slots 140, which can be spaced apart along a second direction (i.e., the y-direction in Figure 3). This second direction can be perpendicular to both the thickness direction and the first direction of the thermal pad 100. In other words, the through-slots 140 are formed on the side of the thermal pad 100 and spaced apart along its side. This effectively increases the amount of adhesive 130 in the thermal pad 100, thereby improving its wave absorption performance.

[0106] The cross-sectional width of the through groove 140 can be 0.1mm to 0.5mm. This value avoids the through groove 140 being too wide, which would affect the content of graphene film 111 and graphene foam film 121 in the thermally conductive pad 100. It also avoids the through groove 140 being too narrow, which would affect the content of adhesive component 130 in the thermally conductive pad 100. This effectively improves the rationality of the distribution of the through groove 140 in the thermally conductive pad 100 and the rationality of the content of adhesive component 130 in the thermally conductive pad 100. While meeting the microwave absorption performance requirements of the thermally conductive pad 100, it effectively improves the thermal conductivity and compressive stress of the thermally conductive pad 100.

[0107] The distance between two adjacent through slots 140 can be 0.2mm to 5mm. This value improves the rationality of the distribution of through slots 140 in the thermal pad 100, preventing excessively large distances between them from reducing the content of the adhesive component 130 in the thermal pad 100, thus affecting the microwave absorption effect of the thermal pad 100 and contributing to improved microwave absorption performance. It also prevents excessively small distances between through slots 140 from affecting the content of graphene film 111 and graphene foam film 121 in the thermal pad 100, thereby affecting the thermal conductivity and compressive stress of the thermal pad 100, effectively improving these properties.

[0108] Figure 8 is a left view of another thermally conductive pad 100 provided in an embodiment of this application.

[0109] In another possible implementation, as shown in Figure 8, the thermal pad 100 may also have a through hole 150. The through hole 150 can penetrate the thermal pad 100 along a first direction, and the adhesive 130 can fill the through hole 150. The adhesive 130 in the through hole 150 can also achieve a wave-absorbing effect, which can effectively increase the content of the adhesive 130 in the thermal pad 100 and effectively improve the wave-absorbing performance of the thermal pad 100. Moreover, by making the through hole 150 penetrate the thermal pad 100 along the first direction, the distribution of the adhesive 130 in the thermal pad 100 can be effectively increased, thereby effectively improving the wave-absorbing performance of the thermal pad 100.

[0110] Referring again to Figure 8, there can be multiple through holes 150, which can be spaced apart along a second direction (i.e., the y-direction in Figure 8). This second direction can be perpendicular to both the thickness direction and the first direction of the thermal pad 100. In other words, the through holes 150 are formed on the side of the thermal pad 100 and spaced apart along its side. This effectively increases the amount of adhesive 130 in the thermal pad 100, thereby improving its wave absorption performance.

[0111] The cross-sectional shape of the through hole 150 can be circular or rectangular. This shape facilitates the processing of the through hole 150, reducing processing costs. The cross-sectional shape of the through hole 150 allows for the inclusion of more adhesive components 130 within it, increasing the content of adhesive components 130 within the thermal pad 100 and enhancing its wave absorption performance.

[0112] Alternatively, in some examples, the shape of the through hole 150 can be other shapes. Specifically, the shape of the through hole 150 can be selected and set according to the specific application scenario of the thermal pad.

[0113] Referring to Figure 8, the maximum cross-sectional dimension of the through-hole 150 can be 0.1mm to 0.5mm. For example, when the cross-sectional shape of the through-hole 150 is circular as shown in Figure 8, the diameter R of the circular through-hole 150 can be 0.1mm to 0.5mm. When the cross-sectional shape of the through-hole 150 is rectangular, the length of the rectangle can be 0.1mm to 0.5mm. When the cross-sectional shape of the through-hole 150 is irregular, the maximum dimension of the irregular through-hole 150 can be 0.1mm to 0.5mm. This can effectively improve the rationality of the cross-sectional dimension of the through-hole 150, and avoid the cross-sectional dimension of the through-hole 150 being too large, which would affect the content of the graphene film assembly 110 and the graphene foam film assembly 120, and thus affect the thermal conductivity and compressive stress of the thermally conductive pad 100, effectively improving the thermal conductivity and compressive stress of the thermally conductive pad 100. Furthermore, it can also prevent the cross-sectional size of the through hole 150 from being too small, which would affect the content of the adhesive 130 in the thermal pad 100 and thus affect the wave absorption effect of the thermal pad 100, thereby effectively improving the wave absorption performance of the thermal pad 100.

[0114] The distance between two adjacent through holes 150 can be 0.2mm to 5mm. This improves the rationality of the distribution of through holes 150 in the thermal pad 100, preventing excessively large distances between through holes 150 from reducing the content of adhesive 130 in the thermal pad 100, thus affecting the microwave absorption effect of the thermal pad 100 and helping to improve the microwave absorption performance of the thermal pad. It also prevents excessively small distances between through holes 150 from affecting the content of graphene film 111 and graphene foam film 121 in the thermal pad 100, which in turn affects the thermal conductivity and compressive stress of the thermal pad 100, effectively improving the thermal conductivity and compressive stress of the thermal pad 100.

[0115] Referring to Figures 1 and 2, the number of graphene films 111 in each graphene film group 110 can be 1 to 3. For example, the number of graphene films 111 in each graphene film group 110 can be 1, 2 (as shown in Figure 2), or 3. This improves the rationality of the graphene film 111 content, avoiding an insufficient number of graphene films 111 that would affect the thermal conductivity and thermal resistance of the thermal pad 100, thus affecting its heat dissipation effect. It effectively improves the thermal conductivity and reduces the thermal resistance of the thermal pad 100. Furthermore, it avoids an excessive number of graphene films 111 that would increase the support of the thermal pad 100, thereby affecting its compressive stress and helping to reduce it. This ensures that the thermal conductivity, thermal resistance, and compressive stress of the thermal pad 100 are at a more reasonable level.

[0116] Referring again to Figures 1 and 2, the number of graphene foam films 121 in each graphene foam film group 120 can be 1 to 15, and the ratio of the number of graphene films 111 to the number of graphene foam films 121 in two adjacent graphene film groups 110 and graphene foam film groups 120 can be 1:1 to 1:5. For example, the number of graphene foam films 121 in each graphene foam film group 120 can be 1, 2, 3 (as shown in Figure 2), 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, etc.

[0117] Specifically, when a graphene film group 110 contains one graphene film 111, the number of graphene films 111 in adjacent graphene film groups 110 can be one, two, three, four, or five, so that the ratio of the number of graphene films 111 to the number of graphene foam films 121 in two adjacent graphene film groups 110 and in graphene foam film group 120 can be 1:1 to 1:5. For example, when a graphene film group 110 contains two graphene films 111, the number of graphene films 111 in adjacent graphene film groups 110 can be two, three, four, five, six, seven, eight, nine, or ten. For example, when the number of graphene films 111 in a graphene film group 110 is 3, the number of graphene films 111 in the adjacent graphene film group 110 can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15.

[0118] This improves the rationality of the graphene foam film 121 content and enhances the proportional coordination between graphene foam film 121 and graphene film 111. It avoids an insufficient amount of graphene foam film 121, which would affect the compressive stress of the thermal pad 100, thus helping to reduce the compressive stress of the thermal pad 100. Furthermore, it avoids an excessive amount of graphene foam film 121, which would affect the thermal conductivity and thermal resistance of the thermal pad 100, thereby impacting its heat dissipation effect. This effectively improves the thermal conductivity and reduces the thermal resistance of the thermal pad 100, enhancing the proportional coordination between graphene foam film 121 and graphene film 111. This ensures that the thermal conductivity, thermal resistance, and compressive stress of the thermal pad 100 are at a more reasonable level.

[0119] It should be noted that within the same thermal pad 100, the ratio of the number of graphene films 111 to the number of graphene foam films 121 in two adjacent graphene film groups 110 and graphene foam film groups 120 can be the same or different between different regions. For example, in one region, the ratio of the number of graphene films 111 to the number of graphene foam films 121 in two adjacent graphene film groups 110 and graphene foam film groups 120 can be 1:1. In another region, the ratio can be 1:2, and so on. In yet another region, the ratio can be 1:3, and so on. Specifically, the ratio of the number of graphene films 111 to the number of graphene foam films 121 in the corresponding part of the electronic device can be adjusted according to the location of the thermal pad 100, so as to improve the flexibility of the graphene films 111 and graphene foam films 121 in the thermal pad 100, thereby effectively improving the overall performance of the thermal pad 100.

[0120] Referring to Figure 2, the thickness d of the graphene film 111 can be 50μm-150μm, for example, 50μm, 80μm, 100μm, 120μm, or 150μm. This thickness effectively improves the rationality of the graphene film 111 thickness. It avoids the graphene film 111 being too thick, which would increase the support of the thermal pad 100 and increase the compressive stress of the thermal pad 100, thus effectively reducing the compressive stress of the thermal pad 100. Moreover, it also avoids the graphene film 111 being too thin, which would affect the thermal conductivity and thermal resistance of the thermal pad 100, thereby affecting the heat dissipation effect of the thermal pad 100. It can effectively improve the thermal conductivity of the thermal pad 100 and reduce the thermal resistance of the thermal pad 100. This allows the thermal pad 100 to achieve high thermal conductivity and low thermal resistance while effectively reducing the support of the graphene film 111 and increasing the compressive stress of the thermal pad 100.

[0121] The in-plane thermal conductivity of the graphene film 111 can be greater than 1000 W / (mK), which can effectively reduce the thermal resistance of the graphene film assembly 110 and improve the thermal conductivity of the graphene film assembly 110, thereby effectively improving the thermal conductivity of the thermal pad 100 and improving the heat dissipation effect of the thermal pad 100.

[0122] The thickness of the graphene foam film 121 can be 300μm-800μm, for example, 300μm, 400μm, 500μm, 600μm, 700μm, or 800μm. This thickness effectively improves the rationality of the graphene foam film 121's thickness. It avoids the graphene foam film 121 being too thick, which would affect the thermal conductivity and thermal resistance of the thermal pad 100, thus affecting the heat dissipation effect of the thermal pad 100. It can effectively improve the thermal conductivity of the thermal pad 100 and reduce its thermal resistance. Moreover, it can also avoid the graphene foam film 121 being too thin, which would affect the compressive stress of the thermal pad 100, thus helping to reduce the compressive stress of the thermal pad 100. This allows the thermal pad 100 to effectively improve its thermal conductivity and reduce its thermal resistance while achieving low compressive stress.

[0123] The graphene foam film 121 has an in-plane thermal conductivity greater than 100 W / (mK). The graphene foam film 121 has a low in-plane thermal conductivity and correspondingly has many pores inside, which can effectively reduce the compressive stress of the graphene foam film 121, thereby effectively improving the compressive stress of the thermal pad 100.

[0124] In this embodiment, the molding material of the adhesive matrix may include at least one of the following: liquid silicone, neoprene rubber, acrylic resin, epoxy resin, polyurethane, polyethylene, polypropylene, phenolic resin, polyvinyl butyral, or ethylene-acetate copolymer. All of these materials possess good adhesive properties, providing a good bond between the graphene foam film assembly 120 and the graphene film assembly 110. This effectively reduces or prevents separation between the graphene foam film assembly 120 and the graphene film assembly 110, effectively improving the strength and reliability of the connection between them, and enhancing the structural stability of the thermal pad 100.

[0125] Preferably, the molding material of the adhesive substrate can be liquid silicone. Liquid silicone has good resistance to high and low temperatures, and can maintain its physical adhesive properties at high temperatures, effectively improving the stability of the adhesive component 130, thereby providing better adhesive performance in the thermal pad 100. Moreover, liquid silicone has good electrical insulation properties, enabling the thermal pad 100 to have good insulation properties, thus providing better insulation protection in the encapsulation of electronic devices.

[0126] The viscosity of the liquid silicone can range from 50 mPa·s to 3000 mPa·s. This viscosity allows the adhesive component 130 to have high adhesive performance, enabling it to achieve a good bonding effect within the thermal pad 100. This effectively reduces or prevents separation between the graphene foam film assembly 120 and the graphene film assembly 110, thereby improving the strength and reliability of the connection between them and enhancing the structural stability of the thermal pad 100.

[0127] In the embodiments of this application, the material of the microwave absorbing filler may include at least one of ferrite, barium titanate, metal micro powder, graphite, or ceramic. All of the above materials have good electrical conductivity and can effectively absorb electromagnetic waves, thus giving the thermal pad 100 good microwave absorption performance.

[0128] Preferably, the material of the microwave absorbing filler can be ferrite or metal micropowder. Ferrite is a magnetic material with good magnetic permeability and resistivity, which can effectively absorb electromagnetic waves and improve the microwave absorption performance of the thermal pad 100. Metal micropowder has high electrical conductivity and magnetic permeability, which can effectively absorb electromagnetic waves and improve the microwave absorption performance of the thermal pad 100. Furthermore, the metal micropowder can be uniformly mixed with the adhesive matrix, allowing the microwave absorbing filler to be evenly distributed in the adhesive matrix, which helps to improve the microwave absorption performance of the adhesive 130.

[0129] Furthermore, the microwave absorbing filler can be flaky iron-silicon-aluminum powder from metal micropowder. Flaky iron-silicon-aluminum powder has good magnetic permeability, which gives the microwave absorbing filler a good microwave absorption effect, enabling the adhesive 130 to effectively absorb energy in the magnetic field part of the electromagnetic wave, thereby effectively improving the microwave absorption performance of the adhesive 130.

[0130] The particle size of the flake-shaped iron-silicon-aluminum powder can range from 200 nm to 500 μm, and particles of different sizes can exhibit different absorption characteristics in different frequency ranges. Smaller nanoparticles generally exhibit better absorption performance in high-frequency bands (such as microwave bands), while larger micron-sized particles may be more effective in lower-frequency bands (such as radio frequency bands). By setting the particle size of the flake-shaped iron-silicon-aluminum powder to the above values, the absorption frequency range of the microwave absorbing material can be effectively increased. Moreover, the above dimensions allow the flake-shaped iron-silicon-aluminum powder to overlap better, which helps to improve the overall microwave absorption performance of the adhesive 130.

[0131] In this embodiment, the weight percentage of the microwave absorbing filler in the adhesive component 130 can be 5% to 50%, meaning the weight of the microwave absorbing filler to the total weight of the adhesive component 130 is 5% to 50%. This ratio improves the reasonableness of the microwave absorbing filler content in the adhesive component 130, preventing insufficient filler content from affecting the microwave absorption and energy absorption of the adhesive component 130, thereby effectively improving its microwave absorption and energy absorption. It also prevents excessive filler content from affecting the adhesive performance of the adhesive component 130, ensuring that the adhesive performance of the adhesive component 130 is met while effectively improving its bonding performance. This allows the adhesive component 130 to achieve a better bonding effect in the thermal pad 100, thereby enhancing the structural stability of the thermal pad 100.

[0132] In this embodiment, the thickness of the thermal pad 100 can be from 0.2mm to 2mm. This thickness avoids excessive thickness, which could affect the thermal conductivity and increase the thermal resistance of the thermal pad 100. It also prevents excessive thickness from increasing the space occupied by the thermal pad 100 in the electronic device, thus improving the internal spatial layout of the electronic device. Furthermore, it avoids the thermal pad 100 being too small, which could lead to poor contact and affect its thermal conductivity and compressive stress. Therefore, while meeting the requirements for thermal conductivity, thermal resistance, and compressive stress, the thermal pad 100 effectively reduces its space occupation, improving the rationality of its placement in the electronic device.

[0133] The preparation method of the thermally conductive pad 100 provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0134] Figure 9 is a flowchart illustrating a method for preparing a thermal pad according to an embodiment of this application; Figure 10 is a structural schematic diagram illustrating a thermal pad blank according to an embodiment of this application; and Figure 11 is a structural schematic diagram illustrating a thermal pad according to an embodiment of this application.

[0135] This application embodiment also provides a method for preparing a thermally conductive pad. This method can be used to prepare a thermally conductive pad 100 for any of the above scenarios. Referring to Figure 9, the preparation method provided in this application embodiment includes:

[0136] S1001: Cut graphene film and graphene foam film into the same shape and size.

[0137] For example, the graphene film 111 and the graphene foam film 121 can be cut to the same size and shape using a laser engraving machine for subsequent use.

[0138] S1002: Adhesive components are prepared by mixing microwave absorbing filler and adhesive matrix.

[0139] For example, liquid silica gel and flake-shaped iron-silicon-aluminum powder can be mixed. The viscosity of the liquid silica gel can be 50 mPa·s to 3000 mPa·s. The particle size of the flake-shaped iron-silicon-aluminum powder can be 200 nm to 500 μm, and the weight content of the microwave absorbing filler in the adhesive matrix can be 5% to 50%.

[0140] S1003: An adhesive is coated on the first graphene foam film, and the adhesive and the graphene foam film are stacked in a first direction, which is the thickness direction of the graphene foam film.

[0141] For example, the adhesive 130 can be coated onto the graphene foam film 121 by spraying, scraping, dispensing or impregnation, so that the adhesive 130 and the graphene foam film 121 are stacked in the first direction (i.e. the x direction in FIG10).

[0142] S1004: A second graphene foam film is laminated on the adhesive along the first direction, and this process is repeated to form a graphene foam film assembly.

[0143] After the adhesive 130 is coated onto the first graphene foam film 121 in step S1003, the adhesive 130 is stacked on the first graphene foam film 121 along the first direction. At this time, a second graphene foam film 121 can be stacked on the adhesive 130 along the first direction. Finally, according to the preset number of graphene foam films 121 in each graphene foam film group 120, the adhesive 130 and the graphene foam film 121 are stacked sequentially to complete the stacking of the corresponding number of graphene foam films 121, thereby forming the first graphene foam film group 120.

[0144] S1005: An adhesive is coated on the last graphene foam film in the graphene foam film assembly so that the adhesive is stacked with the graphene foam film in a first direction, and a first graphene film is stacked on the adhesive along the first direction.

[0145] After the first graphene foam film assembly 120 is formed, an adhesive 130 can be coated on the last graphene foam film 121 (i.e. the topmost graphene foam film 121) of the first graphene foam film assembly 120. Then, a first graphene film 111 is stacked on the adhesive 130 along the first direction, so that the first graphene film 111, the adhesive 130, and the graphene foam film assembly 120 are stacked along the first direction.

[0146] S1006: An adhesive is coated on the first graphene film, and the adhesive and the graphene film are stacked in a first direction. A second graphene film is then stacked on the adhesive along the first direction. This process is repeated to form a graphene film assembly.

[0147] After the adhesive 130 is coated onto the first graphene film 111 in step S1005, the adhesive 130 is stacked on the first graphene film 111 along the first direction. At this time, a second graphene film 111 can be stacked on the adhesive 130 along the first direction. Finally, according to the number of graphene films 111 in each pre-set graphene film group 110, the stacking of graphene films 111 is completed to form the first graphene film group 110, and the graphene film group 110 and the graphene foam film group 120 are stacked together along the first direction.

[0148] S1007: Prepare a graphene foam film on the graphene film, and prepare a graphene film on the graphene foam film again. Repeat this process to obtain a thermal pad blank of a predetermined thickness.

[0149] For example, referring to Figure 10, according to the preset height requirement of the thermal pad blank, the graphene foam film 121 and the graphene film assembly 110 can be stacked sequentially and repeatedly so that the graphene foam film assembly 120 and the graphene film assembly 110 can be alternately stacked along the first direction. Once the preset height requirement of the thermal pad blank is reached, the stacking of the graphene foam film assembly 120 and the graphene film assembly 110 can be stopped. The height of the thermal pad blank can be set according to the width or length requirements of the thermal pad 100.

[0150] S1008: Heating and curing the thermal pad blank.

[0151] After the thermal pad blank is prepared, it can be heated to solidify it, so that it can be cut later. For example, the drying temperature can be 80℃ and the drying time can be 2 hours.

[0152] S1009: Cut the thermal pad blank along a plane perpendicular to the third direction to obtain the pad blank. The third direction is perpendicular to the first direction and is the thickness direction of the pad blank.

[0153] Referring to Figures 10 and 11, the third direction can be the z-direction in the figures. After the preparation of the thermal pad blank is completed, the thermal pad blank can be cut along a plane perpendicular to the stacking direction of the graphene foam film group 120 and the graphene film group 110 to obtain the pad blank. For example, it can be cut by processes such as room temperature or low temperature diamond wire cutting, ultrasonic cutting, and blade cutting.

[0154] In the obtained gasket blank, the graphene foam film group 120 and the graphene film group 110 are alternately stacked along the direction perpendicular to the thickness of the gasket blank. This is consistent with the placement of the graphene foam film group 120 and the graphene film group 110 in the thermally conductive gasket 100 described in the above scenario.

[0155] S1010: Treating the gasket blank in a silicone cleaning agent.

[0156] During the cutting process of the heatsink blank, the adhesive component 130 is also cut, leaving adhesive particles on the cut surface. These particles can affect the manufacturing accuracy of the thermal pad and its subsequent use. A silicone cleaner can effectively remove these residual adhesive particles from the heatsink blank, improving the manufacturing accuracy of the thermal pad 100. For example, the treatment time in the silicone cleaner can be 10 seconds.

[0157] S1011: Ultrasonic treatment of the gasket preform in ethanol.

[0158] After treating the gasket preform in the silicone cleaning agent in step S1010, most of the residual adhesive particles can be removed, but some stubborn residual adhesive particles may still remain and are difficult to remove effectively. At this point, ultrasonic treatment can more effectively remove the stubborn residual adhesive particles. This effectively removes residual adhesive particles from the gasket preform, improving the manufacturing precision and yield of the thermal pad 100. For example, the ultrasonic treatment in ethanol can last for 3 minutes.

[0159] S1012: The gasket blank is dried to obtain a thermally conductive gasket.

[0160] After removing the residual adhesive particles from the gasket blank through steps S1010 and S1011, the gasket blank can be dried to obtain the final thermally conductive gasket 100.

[0161] The above preparation method can effectively produce a thermally conductive pad 100 with high thermal conductivity, low thermal resistance, low compressive stress and high wave absorption performance, which can effectively solve the problems of low thermal conductivity, high compressive stress and poor wave absorption performance of the thermally conductive pad 100.

[0162] Figure 12 is a schematic diagram of a rectangular through hole provided in the example of this application, and Figure 13 is a schematic diagram of a circular through hole provided in the embodiment of this application.

[0163] Before coating the adhesive onto the first graphene foam film in step S1003, i.e. after cutting the graphene film 111 and the graphene foam film 121 to the same shape and size in step S1001, the preparation method may further include:

[0164] S10011: Through holes of the same size and arrangement are opened on graphene film and graphene foam film.

[0165] For example, through holes 150 can be formed on the graphene film 111 and the graphene foam film 121 by laser engraving. The through holes 150 can be distributed on the graphene film 111 and the graphene foam film 121 in an array, and the interval between two adjacent through holes 150 can be 0.2 mm to 5 mm.

[0166] When the adhesive 130 is coated on the graphene film 111 and the graphene foam film 121, it also fills the through holes 150 on the graphene film 111 and the graphene foam film 121.

[0167] For example, referring to Figures 12 and 13, the shape of the through-hole 150 can be rectangular as shown in Figure 12, or circular as shown in Figure 13. When the adhesive 130 is coated onto the graphene film 111 and the graphene foam film 121, the adhesive 130 can be inserted into the through-hole 150 on the graphene film 111 and the graphene foam film 121. During the stacking process of the graphene film 111 and the graphene foam film 121, the through-holes 150 on the graphene film 111 and the graphene foam film 121 can be aligned one by one. When the graphene film assembly 110 and the graphene foam film assembly 120 are alternately stacked to form a thermally conductive pad blank, the through-hole 150 can penetrate the thermally conductive pad blank along the stacking direction (i.e., the first direction) of the graphene film assembly 110 and the graphene foam film assembly 120.

[0168] After the gasket blank is cut, the through hole 150 will be located on the side of the gasket blank. After the gasket blank is cleaned of adhesive particles and dried to form the thermally conductive gasket 100, the through hole 150 will be located on the side of the thermally conductive gasket 100 and will penetrate the thermally conductive gasket 100 along the stacking direction of the graphene film assembly 110 and the graphene foam film assembly 120 (i.e., the first direction).

[0169] During the cutting process of the thermal pad blank, the cutting line may or may not pass through the through hole 150. For example, when the cross-section of the through hole 150 is circular as shown in Figure 13, the cutting line may not pass through the through hole 150, meaning the through hole 150 is not cut. In this case, the formed thermal pad 100 will not have grooves filled with the adhesive 130, that is, the upper surface of the thermal pad 100 will not have a resin stripe structure, such as the structure shown in Figure 8.

[0170] When the cross-section of the through hole 150 is rectangular as shown in Figure 12, the cutting line can pass through the through hole 150. At this time, the formed thermal pad 100 will have a groove 140 filled with the adhesive 130 (as shown in Figures 1, 4, etc.), that is, a resin stripe structure will appear on the thermal pad 100.

[0171] Preferably, the cross-sectional shape of the through hole 150 can be rectangular, and the cutting line can pass through the through hole 150. The rectangular length is relatively long, which makes it easier to have adhesive 130 in the thickness direction of the thermal pad 100 during the cutting process. This can effectively increase the proportion of adhesive 130 in the thermal pad 100, which is beneficial to improving the wave absorption performance of the thermal pad 100.

[0172] The following analysis examines the various performance characteristics of the thermally conductive pad 100 provided in the embodiments of this application through different examples.

[0173] Figure 14 shows the compressive stress-strain curves of graphene film / foam laminates with different ratios provided in Embodiments 1, 2, and 3 of this application.

[0174] Example 1

[0175] A thermally conductive pad 100 was prepared using the above method. The graphene film 111 in the thermally conductive pad 100 has a thickness of 100 μm and an in-plane thermal conductivity > 1000 W / (mK). The graphene foam film 121 has a thickness of 400 μm and a density of 0.13 g / cm³. 3 The in-plane thermal conductivity is >100 W / (mK). A through-groove 140 may be formed on the thermally conductive pad 100, extending through the thermally conductive pad 100 along a first direction and extending through the thickness direction of the thermally conductive pad 100. The adhesive 130 may be pure liquid silicone, meaning that the adhesive 130 does not contain microwave absorbing filler. The ratio of the number of graphene films 111 to the number of graphene foam films 121 in two adjacent graphene film groups 110 and graphene foam film groups 120 may be 1:4.

[0176] The fitted thermal conductivity of thermal pad 100 was measured to be 92.6 W / (mK), and the thermal resistance was 0.41 Kcm. 2 / W(2mm@40psi), this thermal resistance indicates that the thermal pad 100 has a thickness of 2mm and a thermal resistance of 0.41Kcm at 40psi. 2 / W. Referring to Figure 14, curve S1 in Figure 14 (i.e., the black RS-1 curve in Figure 14) is the compressive stress-strain curve of the thermal pad 100 in Example 1. As can be seen from curve S1 in Figure 14, the average residual compressive stress of the thermal pad tested by the mechanical testing machine is 36.7 psi, and the average compression rebound rate is 87.48%.

[0177] Figure 15 shows the microwave absorption isolation test results of a thermally conductive pad provided in Embodiment 2 of this application.

[0178] Example 2

[0179] A thermally conductive pad 100 is prepared using the above-described method. The graphene film 111 in the thermally conductive pad 100 has a thickness of 100 μm and an in-plane thermal conductivity > 1000 W / (mK). The graphene foam film 121 has a thickness of 600 μm and an in-plane thermal conductivity of 100 W / (mK). A through-groove 140 can be formed on the thermally conductive pad 100, penetrating along a first direction and extending through the thickness direction of the thermally conductive pad 100. The adhesive 130 can be pure liquid silicone, meaning it does not contain microwave-absorbing fillers. The ratio of the number of graphene films 111 to the number of graphene foam films 121 in two adjacent graphene film groups 110 and graphene foam film groups 120 can be 1:1.

[0180] The thermally conductive pad 100 provided in Example 2 differs from the thermally conductive pad 100 provided in Example 1 in that the graphene foam film 121 in Example 2 has a thickness of 600 μm and a thermal conductivity of 100 W / mK. The ratio of the number of graphene films 111 to the number of graphene foam films 121 in two adjacent graphene film groups 110 and graphene foam film groups 120 can be 1:1. All other parts are identical.

[0181] The fitted thermal conductivity of thermal pad 100 was measured to be 143.8 W / (mK), and the thermal resistance was 0.346 Kcm. 2 / W(2mm@40psi), this thermal resistance indicates that the thermal pad 100 has a thickness of 2mm and a thermal resistance of 0.346Kcm at 40psi. 2 / W. Referring to Figure 14, curve S2 (also the green RS-4 curve in Figure 14) is the compressive stress-strain curve of the thermal pad 100 in Example 2. As shown by curve S2 in Figure 14, the average residual compressive stress of the thermal pad, tested using a mechanical testing machine, is 29.3 psi, and the average compression rebound rate is 90.47%. Furthermore, referring to Figure 15, curve S4 is the background curve, and curve S5 is the microwave absorption isolation curve of the thermal pad 100 in Example 2. As shown in Figure 15, the microwave absorption isolation of the thermal pad 100 in the 0.1-4 GHz frequency band is less than -80 dB.

[0182] Comparing the test results of Example 2 and Example 1, it can be concluded that the thermal resistance, thermal conductivity, compressive residual stress, and resilience of the obtained thermal pad 100 can be controlled by adjusting the density and thermal conductivity of the graphene foam film 121. Simultaneously, the perforated surfaces of the graphene film 111 and the graphene foam film 121 create resin stripes on the surface of the thermal pad. This improves the interlayer adhesion between adjacent graphene films 111 and 121, and also allows the graphene films 111 and 121 themselves to dissipate electromagnetic waves through dielectric loss, giving the thermal pad excellent wave absorption capabilities.

[0183] Figure 16 shows the microwave absorption isolation test results of a thermally conductive pad provided in Embodiment 3 of this application.

[0184] Example 3

[0185] A thermally conductive pad 100 is prepared using the above-described method. The graphene film 111 in the thermally conductive pad 100 has a thickness of 100 μm and an in-plane thermal conductivity > 1000 W / (mK). The graphene foam film 121 has a thickness of 600 μm and an in-plane thermal conductivity of 100 W / (mK). A through-groove 140 can be formed on the thermally conductive pad 100, extending through the thermally conductive pad 100 along a first direction and extending through the thickness direction of the thermally conductive pad 100. The adhesive 130 is a mixture of liquid silicone and sheet-like iron-silicon-aluminum powder, meaning that the adhesive 130 contains microwave-absorbing filler. The mass ratio of the microwave-absorbing filler in the adhesive 130 can be 30%. The ratio of the number of graphene films 111 to the number of graphene foam films 121 in two adjacent graphene film groups 110 and graphene foam film groups 120 can be 1:1.

[0186] The thermally conductive pad 100 provided in Example 3 differs from the thermally conductive pad 100 provided in Example 2 in that the adhesive component 130 in the thermally conductive pad 100 of Example 3 contains microwave absorbing filler. All other parts are the same.

[0187] The fitted thermal conductivity of thermal pad 100 was measured to be 163.1 W / (mK), and the thermal resistance was 0.309 Kcm. 2 / W(2mm@40psi). Referring to Figure 14, curve S3 (also the red RS-2 curve in Figure 14) is the compressive stress-strain curve of the thermal pad 100 in Example 3. As shown by curve S3 in Figure 14, the average residual compressive stress of the thermal pad, tested using a mechanical testing machine, is 36.5psi, and the average compression rebound rate is 85.9%. Furthermore, referring to Figure 16, the curve in Figure 16 is the microwave absorption isolation curve of the thermal pad 100 in Example 3. As shown by Figure 16, the microwave absorption isolation of the thermal pad 100 in the 0.1-6GHz frequency band is less than -78dB.

[0188] Comparing the test results of Example 3 and Example 2, it can be concluded that by adding microwave absorbing filler inside the adhesive matrix, the microwave absorption capability of the thermal pad 100 can be effectively improved. Under the condition that the thermal resistance and compressive residual stress do not change much, the frequency band with microwave absorption isolation of less than -78dB can be further extended to the 0.1-6GHz frequency band.

[0189] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0190] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0191] It should be readily understood that the terms “on,” “above,” and “on top of” in this disclosure should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0192] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0193] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal connection of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances. The terms "first," "second," "third," "fourth," etc. (if present) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0194] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them. Although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A thermally conductive pad, characterized in that, include: One or more graphene film modules (110); One or more graphene foam film groups (120), wherein the one or more graphene foam film groups (120) and the one or more graphene film groups (110) are stacked and alternately arranged along a first direction, the first direction being perpendicular to the thickness direction of the thermal pad (100); The density of each of the graphene foam film groups (120) is less than the density of each of the graphene film groups (110); An adhesive component (130) is located between two adjacent graphene film groups (110) and graphene foam film groups (120), and the two adjacent graphene film groups (110) and graphene foam film groups (120) are bonded together by the adhesive component (130). Each of the adhesive components (130) includes an adhesive matrix and a microwave absorbing filler mixed together, the adhesive matrix being used to provide adhesive properties and the microwave absorbing filler being used to absorb microwaves.

2. The thermally conductive pad according to claim 1, characterized in that, Each of the graphene film groups (110) includes one or more graphene films (111) stacked along the first direction; The adhesive (130) is also located between two adjacent graphene films (111), and the two adjacent graphene films (111) are bonded together by the adhesive (130).

3. The thermally conductive pad according to claim 2, characterized in that, Each of the graphene foam film groups (120) includes one or more graphene foam films (121) stacked along the first direction; The adhesive (130) is also located between two adjacent graphene foam films (121), and the two adjacent graphene foam films (121) are bonded together by the adhesive (130).

4. The thermally conductive pad according to any one of claims 1 to 3, characterized in that, The thermal pad is also provided with a through groove (140), which penetrates the thermal pad along the first direction; The adhesive (130) also fills the through groove (140).

5. The thermally conductive pad according to claim 4, characterized in that, The number of through slots (140) is multiple, and the multiple through slots (140) are distributed at intervals along a second direction, which is perpendicular to the thickness direction of the thermal pad and the first direction.

6. The thermally conductive pad according to claim 2, characterized in that, The number of graphene films (111) in each graphene film group (110) is 1 to 3.

7. The thermally conductive pad according to claim 2 or 6, characterized in that, The thickness of the graphene film (111) is 50 μm to 150 μm.

8. The thermally conductive pad according to claim 6 or 7, characterized in that, The in-plane thermal conductivity of the graphene film (111) is greater than 1000 W / (mK).

9. The thermally conductive pad according to claim 3, characterized in that, The number of graphene foam films (121) in each graphene foam film group (120) is 1 to 15, and the ratio of the number of graphene films (111) in two adjacent graphene film groups (110) to the number of graphene foam films (121) in the graphene foam film group (120) is 1:1 to 1:

5.

10. The thermally conductive pad according to claim 3 or 9, characterized in that, The thickness of the graphene foam film (121) is 300 μm to 800 μm.

11. The thermally conductive pad according to claim 9 or 10, characterized in that, The in-plane thermal conductivity of the graphene foam film (121) is greater than 100 W / (mK).

12. The thermally conductive pad according to any one of claims 1 to 11, characterized in that, The molding material of the adhesive matrix includes at least one of liquid silicone, chloroprene rubber, acrylic resin, epoxy resin, polyurethane, polyethylene, polypropylene, phenolic resin, polyvinyl butyral, or ethylene-acetic acid copolymer.

13. The thermally conductive pad according to claim 12, characterized in that, The molding material for the adhesive substrate is liquid silicone.

14. The thermally conductive pad according to claim 13, characterized in that, The viscosity of the liquid silica gel is 50 mPa·s to 3000 mPa·s.

15. The thermally conductive pad according to any one of claims 1 to 14, characterized in that, The material of the microwave absorbing filler includes at least one of ferrite, barium titanate, metal micro powder, graphite or ceramic.

16. The thermally conductive pad according to claim 15, characterized in that, The microwave absorbing filler is made of ferrite or metal powder.

17. The thermally conductive pad according to claim 16, characterized in that, The material of the microwave absorbing filler is flaky iron-silicon-aluminum powder from metal micropowder.

18. The thermally conductive pad according to claim 17, characterized in that, The particle size of the flake-shaped iron-silicon-aluminum powder is 200 nm to 500 μm.

19. The thermally conductive pad according to any one of claims 1 to 18, characterized in that, The microwave absorbing filler has a weight content of 5% to 50% in the adhesive (130).

20. The thermally conductive pad according to any one of claims 1 to 3, characterized in that, The thermal pad is also provided with a through hole (150), which penetrates the thermal pad along the first direction; The adhesive (130) also fills the through hole (150).

21. The thermally conductive pad according to claim 20, characterized in that, The number of through holes (150) is multiple, and the multiple through holes (150) are distributed at intervals along a second direction, which is perpendicular to the thickness direction of the thermal pad and the first direction.

22. The thermally conductive pad according to claim 20 or 21, characterized in that, The cross-sectional shape of the through hole (150) includes rectangular or circular shapes.

23. The thermally conductive pad according to any one of claims 20 to 22, characterized in that, The maximum cross-sectional dimension of the through hole (150) is 0.1mm to 0.5mm.

24. The thermally conductive pad according to claim 5, characterized in that, The distance between two adjacent through slots (140) is 0.2mm to 5mm.

25. The thermally conductive pad according to claim 4, 5, or 24, characterized in that, The width of the cross-section of the through groove (140) is 0.1mm to 0.5mm.

26. The thermally conductive pad according to any one of claims 1 to 25, characterized in that, The thickness of the thermal pad is 0.2mm to 2mm.

27. An electronic device, characterized in that, It includes a power device and a thermal pad as described in any one of claims 1 to 26, wherein the thermal pad covers the power device.

28. An electronic device, characterized in that, Includes the electronic device described in claim 27 above.

29. A method for preparing a thermally conductive pad, used to prepare the thermally conductive pad according to any one of claims 1 to 26, characterized in that, The method includes: An adhesive (130) is coated on the first graphene foam film (121) so that the adhesive (130) and the graphene foam film (121) are stacked in a first direction, the first direction being the thickness direction of the graphene foam film (121). A second graphene foam film (121) is stacked on the adhesive (130) along the first direction, and this process is repeated to form a graphene foam film assembly (120); The adhesive (130) is coated on the last graphene foam film (121) in the graphene foam film assembly (120) so that the adhesive (130) and the graphene foam film (121) are stacked in the first direction, and the first graphene film (111) is stacked on the adhesive (130) along the first direction; The adhesive (130) is coated on the first graphene film (111), and the adhesive (130) and the graphene film (111) are stacked in the first direction. A second graphene film (111) is stacked on the adhesive (130) along the first direction. This process is repeated to form a graphene film assembly (110). The graphene foam film group (120) is prepared again on the graphene film group (110), and the graphene film group (110) is prepared again on the graphene foam film group (120), and this cycle is repeated to obtain a thermal pad blank of a preset thickness. The thermal pad blank is heated and cured; The thermal pad blank is cut along a plane perpendicular to a third direction to obtain a gasket blank. The third direction is perpendicular to the first direction and is the thickness direction of the gasket blank.

30. The preparation method according to claim 29, characterized in that, The thermal pad is also provided with a through hole (150), the through hole (150) penetrates the thermal pad along the first direction, and the adhesive (130) is also filled in the through hole (150); Before coating the adhesive (130) onto the first graphene foam film (121), the preparation method further includes: Through holes (150) of the same size and arrangement are formed on the graphene film (111) and the graphene foam film (121); When the adhesive (130) is coated on the graphene film (111) and the graphene foam film (121), it also fills the through holes (150) on the graphene film (111) and the graphene foam film (121).

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