Compressible and resilient porous composite thermal interface material, heat dissipation device and heat source device thermal interface structure

Abstract

The invention discloses a porous composite thermal interface material capable of compressing and rebounding. The porous composite thermal interface material comprises a porous heat-conducting framework body, a compressing and rebounding enhancing mechanism and a compressing and limiting device. A porous heat-conducting framework body serves as a base body, elasticity of the porous heat-conducting framework body is enhanced through a compression springback enhancing mechanism, and a compression limiting device is arranged in the base body. And the filler with high heat conductivity coefficient is used for supplementary heat conduction. The invention further discloses a heat dissipation device and a heat source device thermal interface structure, the porous heat conduction framework body and the heat source device or the heat dissipation device are integrated, and the surface of the connecting end face of the heat source device or the heat dissipation device is subjected to porous treatment, so that a layer of porous heat conduction framework body is formed; a corresponding compression springback enhancing mechanism and a compression limiting device are arranged, and a heat conduction filling agent is filled and supplemented. The thermal interface material constructs a stable and short heat conduction channel, and the heat conductivity coefficient is easy to reach a 100w / mK level.

Description

Technical Field

[0001] This invention belongs to the field of thermal interface material technology, and discloses a compressible and resilient porous composite thermal interface material and a heat dissipation device and a thermal interface structure for a heat source device. Background Technology

[0002] Currently, the design and application of high power density devices are heavily constrained by heat dissipation capabilities. Their power, performance, operating mode, reliability, and lifespan all depend on heat dissipation capabilities.

[0003] The bottleneck in heat dissipation typically lies in the thermal interface layer connecting the heat source and the heat dissipation equipment. This is because the materials commonly used in this layer have extremely low thermal conductivity, creating a significant gap compared to the thermal conductivity of the heat source and heat dissipation equipment, which is generally >200 W / mK. Under the influence of a heat source of 100 W / cm², if the thermal interface layer's thermal conductivity is less than 50 W / mK, a temperature gradient difference >30 degrees Celsius will form between the heat source and the heat sink. A thermal interface material with a thermal conductivity of 50 W / mK is already difficult to achieve with current technology. Furthermore, if the equipment's power density is greater than 200 W / cm², a thermal interface material with an even higher thermal conductivity is required.

[0004] 1. Traditional thermal interface materials use liquids or elastomers with low thermal conductivity as the matrix to fill the gaps between the interfaces, and use high thermal conductivity materials as fillers as the main heat conduction mechanism. Because the proportion of the matrix material is relatively large, its extremely low thermal conductivity severely restricts the improvement of the overall thermal conductivity. Furthermore, the scattered heat conduction channels constructed by the fillers account for a relatively small proportion, and the probability of contact between them is limited, resulting in a generally low overall thermal conductivity.

[0005] 1.1 Fluid polymer-high thermal conductivity particulate filler type, a typical silicone grease thermal conductive material, namely dimethylsilane is a viscous solution formed by adding fillers such as aluminum, alumina, zinc oxide, silver, boron nitride, silicon carbide, aluminum nitride, and diamond.

[0006] Fluid-type matrices are prone to complete evaporation, resulting in a short service life. For example, dimethylsilane will evaporate completely within 1-2 years under high-temperature conditions. After the matrix evaporates, high-hardness fillers remain. Under the combined effects of external mechanical compression and heat source heating, which soften the interface, the originally extremely low-level roughness surfaces of the heat source and radiator will be pitted and uneven. The uneven surface forms several columnar connections between the heat source and radiator, which are connected by ceramic particles, becoming a new thermal interface layer that needs to be filled.

[0007] Its overall thermal conductivity is generally between 1 and 5 W / mK. To pursue the ultimate thermal conductivity, it can be achieved by significantly increasing the filler concentration. For example, the extreme dimethylsilane-aluminum nitride can reach 12 W / mK. However, because the aluminum nitride concentration is too high, it becomes too viscous and has poor fluidity, making it difficult to spread, unable to effectively fill gaps, and resulting in insufficient contact area. Furthermore, the dimethylsilane content is too low, leading to a faster evaporation rate.

[0008] 1.2 Solid Polymer-High Thermal Conductivity Particle Filler Type: Typical thermally conductive silicone uses a silicone matrix as the base, with embedded high thermal conductivity microparticles. Solid silicone avoids evaporation and has a long service life. However, the thermal conductivity of the silicone matrix is ​​<0.5w / mK, which is too low, and the overall limiting thermal conductivity is around 20w / mK.

[0009] 1.3 Solid polymer-high thermal conductivity wire mesh type: Typical graphite heat spreader film. Due to the need to add organic polymers with low thermal conductivity to maintain its elasticity, the surface organic polymer residue or backing adhesive is used to adhere to the heat source. The filament bundles are filled and isolated by organic polymers. Its linear heat conduction path is relatively long compared to other methods, resulting in a low thermal conductivity in the vertical direction. Its overall vertical thermal conductivity is about 10w / mK. However, composite materials that introduce high thermal conductivity fibers and improve the vertical heat conduction path can achieve 15w / mK (Invention application publication number CN119953034A A high compression resilience thermal interface material and its preparation method).

[0010] 1.4. Phase Change from Solid to Fluid - High Thermal Conductivity Particle Filler Type: Among materials with a thermal conductivity exceeding 20 W / mK, liquid alloys are a typical example, but a thermal conductivity of around 35 W / mK still cannot meet the requirements. According to the national standard GB / T43611-2023, the thermal conductivity of gallium-based liquid alloy type I can reach 24–35 W / mK.

[0011] The bismuth-based phase change thermal conductive sheet is a mixture of bismuth, indium, and copper, with a thermal conductivity of approximately 35 W / mK.

[0012] However, liquid alloys cannot be used when the entire machine is immersed in a cooling liquid environment, and they generally contain rare metals, which limits their price and usage.

[0013] 2. Among methods with a thermal conductivity exceeding 50 W / mK, welding is currently the most common approach, typically using tin as the solder. High-quality welding in factory workshops achieves an overall thermal conductivity between 50 and 70 W / mK. However, this level of quality is difficult to achieve in typical outdoor or residential applications. Using copper or silver, which have even higher thermal conductivity, requires expensive equipment, high energy consumption, and advanced technology. The fixed welding method also makes component replacement inconvenient in non-production environments.

[0014] 3.1 Porous dielectric metals possess a certain degree of ductility. Under pressure, the porous microstructures on the upper and lower surfaces collapse, fully filling the surfaces of the heat source and radiator with different roughnesses, thus tightly connecting the two interfaces. Moreover, the metal itself has a high thermal conductivity; porous metals with 99% porosity can retain 50% to 80% of their thermal conductivity when compressed to 20-50%.

[0015] However, most metals with high thermal conductivity lack elasticity and have poor microstructure shape recovery. Under external high pressure and high temperature, they expand to fully fill the gaps between the two interfaces. After cooling, the porous metal microstructure collapses, with varying shrinkage rates, forming surfaces with inconsistent roughness. Between the heat source and the radiator, these become a few supporting pillars, with only a few support points formed by the collapsed structure serving as heat conduction channels. The thermal conductivity drops sharply, forming a new thermal interface layer that needs to be filled. This characteristic makes their usable lifespan extremely short, almost like a disposable product.

[0016] 3.2. Spring steel and spring copper, which have better springback and recovery capabilities, also have the problem of structural collapse due to overcompression. Summary of the Invention

[0017] In order to overcome the shortcomings of existing technologies, such as the low thermal conductivity of the substrate in conventional thermal interface technology, the short lifespan caused by the evaporation of liquid substrate, and the low proportion and instability of heat dissipation point type heat conduction channels; The matrix contains rare metals; Welding technology is difficult, energy-intensive, costly, and has poor substitutability; High thermal conductivity metals, when porous, lack elasticity, have weak shape recovery ability, and short effective lifespan. Problems such as high compressibility and resilience, and poor thermal conductivity in porous metals. This invention provides a compressible and resilient porous composite thermal interface material and a thermal interface structure for heat dissipation devices and heat source devices. A dense, high-thermal-conductivity porous material is used as the matrix and as the primary heat conduction mechanism. A compression-rebound enhancement mechanism is employed to increase its elasticity, allowing it to repeatedly fill the gaps between interfaces. A compression limiting structure is provided to prevent over-compression and structural collapse. High-thermal-conductivity fillers are used as supplementary heat conduction.

[0018] The technical solution adopted in this invention is: a compressible and resilient porous composite thermal interface material, comprising a porous thermally conductive skeleton, a compression and resilience enhancement mechanism, and a compression limiting device.

[0019] Using a porous thermally conductive skeleton as the matrix, a compression-rebound enhancement mechanism is used to elastically enhance the porous thermally conductive skeleton, and a compression limiting device is arranged in the matrix.

[0020] The aforementioned porous thermally conductive framework is a porous material with a thermal conductivity of not less than 30 W / mK in its dense form and possesses a certain degree of ductility. It includes, but is not limited to, at least one of foamed iron, foamed aluminum, foamed copper, foamed silver, and their alloys.

[0021] The compression and springback enhancement mechanism is to enhance the compression and springback of the porous thermally conductive skeleton, including but not limited to at least one of alloying, microskeleton coating, microparticle filling, and sandwich.

[0022] The compression rebound enhancement mechanism uses materials that can maintain rebound performance at temperatures below 60 degrees Celsius, including but not limited to any one of silicone, polyurethane, spring steel, copper for springs and their plating.

[0023] The compression limiting device described herein is one or more of the following: According to its distribution pattern, it can be uniformly arranged at a certain distance, randomly scattered at multiple points, with rolled edges, with side strips, or embedded in a sandwich shape; wherein, the side strip shape can be a single side, double sides, four sides, or a grid; according to its microscopic shape, it can be spherical, columnar, solid line, or porous foam; wherein, the spherical or columnar shape is a high thermal conductivity material, and can be a bead or columnar structure of copper, silver, etc., with the diameter of the bead particles and the height of the column not less than 1 / 8 of the overall thickness; the strip shape is the same material as the porous thermally conductive skeleton; if it is with rolled edges or embedded in a sandwich shape, it can have the same porosity and pore size; if they are connected together on the same plane, it represents a higher density form of the material, and is one of the following: a non-porous solid material with lower porosity, smaller pore size, and lower thickness.

[0024] The aforementioned compressible and resilient porous composite thermal interface material, wherein the porous thermally conductive framework has its upper and lower surfaces uniformly filled with a supplementary thermally conductive filler, which consists of a thickener and a high thermal conductivity particulate filler. The thickener is generally either dimethylsilane or purified water. The high thermal conductivity particulate filler is in the form of particles or droplets, with a thermal conductivity of not less than 30 W / mK and not less than the thermal conductivity of the porous thermally conductive framework after 30% compression, including at least one of the following materials: metal powders such as aluminum, copper, and silver; nitrides such as aluminum nitride and boron nitride; oxides such as alumina, zinc oxide, and beryllium oxide; carbide materials such as silicon carbide and boron carbide; and highly oriented carbon materials such as graphite, diamond, and carbon nanotubes.

[0025] The aforementioned compressible and resilient porous composite thermal interface material is sheet-like and composed of multiple layers. The top and bottom layers form a porous thermally conductive framework, while the middle layers consist of a compression-limiting interlayer and an elastic reinforcing interlayer. The interlayers are connected by a high-temperature resistant adhesive. The elastic reinforcing interlayer also serves as an adhesive between the upper and lower layers. Thermally conductive fillers are applied to the surfaces of the top and bottom layers. The compression-limiting interlayer and the porous thermally conductive framework are made of the same material and are distributed in any of the following ways: the compression-limiting interlayer surrounds the elastic reinforcing interlayer on all four sides, or is located on both sides of the elastic reinforcing interlayer; the elastic reinforcing interlayer is either polyurethane or silicone, and is distributed in any of the following ways: applied to the corresponding inner layers of the top and bottom layers, or placed as an independent sheet between the top and bottom layers.

[0026] The aforementioned compressible and resilient porous composite thermal interface material consists of two layers bonded together by a high-temperature resistant adhesive. The top and bottom layers form a porous thermally conductive framework, with compression limiting devices distributed around or on both sides of the top and bottom layers. These frameworks are homogeneous materials with varying porosities or pore sizes. The compression-resilient enhancement mechanism is distributed between the top and bottom layers and coated on their corresponding inner surfaces.

[0027] The aforementioned compressible and resilient porous composite thermal interface material is a single-layer sheet. Its compression and resilience enhancement mechanism is a micro-scaffold encapsulation type. The compression and resilience material encapsulates the pores in the porous thermal conductive skeleton and connects the skeleton. The upper and lower surfaces of the porous thermal conductive skeleton do not contain compression and resilience enhancement mechanism material with low thermal conductivity.

[0028] The aforementioned compressible and resilient porous composite thermal interface material is a single-layer sheet, and the porous thermally conductive skeleton, the compression and resilience enhancement mechanism, and the compression limiting device are all made of either iron or copper, which are highly elastic alloys.

[0029] Embodiment 7 of the present invention provides a heat dissipation device and a heat source device thermal interface structure. The porous thermally conductive skeleton and the heat source device or heat dissipation device are integrated. The surface of the connecting end face of the heat source device or heat dissipation device is porousized to form a porous thermally conductive skeleton. According to Embodiment 1 or 2, a corresponding compression rebound enhancement mechanism and compression limiting device are provided, and supplementary thermally conductive filler is added. The heat source device or heat dissipation device includes, but is not limited to, any of the following: heat pipe end, connecting end face of heat dissipation fins and the hot end, the connection part between the inner side of the back shell of a heat dissipation device such as a mobile phone, tablet computer, or LCD monitor and a component inside the casing that is prone to heat generation, the connecting end face of a water-cooled thermally conductive block, the connecting end face of a chip encapsulation layer and a heat sink, the socket insertion clamping surface, the connecting end face of a laser and a heat sink, and the hot-cold interface heat transfer end face of a hot melt extruder.

[0030] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0031] 1. For example Figure 4 As shown, this invention utilizes a high thermal conductivity matrix and filler to construct a stable and short thermal conduction channel, in which the volume percentage of the high thermal conductivity material is >60%, and the thermal conductivity easily reaches the level of 100 W / mK. Even the worst porous spring steel filled with aluminum nitride, because the thermal conductivity of the porous spring steel matrix is ​​more than twice that of silicone, and can reach 10 times after extrusion, with a higher aluminum nitride particle filling rate and a larger proportion of high thermal conductivity material, can achieve a thermal conductivity that surpasses that of thermally conductive silicone-aluminum nitride filler (<20 W / mK). Commonly used porous copper, depending on the compression ratio, can achieve a thermal conductivity of 70–200 W / mK, while porous silver can reach 300 W / mK.

[0032] 2. Long service life; it can still maintain 90% of its effectiveness after 10,000 cycles.

[0033] 3. The surface roughness requirement is not high, which reduces the requirements for production equipment and costs of related products.

[0034] 4. The support strength of the designed bracket can be adjusted by replacing the limiting compression rebound enhancement mechanism and compression limiting device as needed. Attached Figure Description

[0035] Figure 1 This is a side view of the overall structure; Figure 2 This is a schematic diagram of the compression and rebound enhancement mechanism; Figure 3 This is a schematic diagram of a compression limiting device; Figure 4 This is a schematic diagram of the heat conduction channel; Figure 5 This is a schematic diagram of the sandwich structure; Figure 6 This is a schematic diagram of a component that is integrally fixed to the connection end face of a heat source or radiator.

[0036] In the figure, 1. Porous thermally conductive framework, 2. Compression and rebound enhancement mechanism, 3. Compression limiting device, 4. Add thermally conductive filler. 200 compression-free springback reset, 201 Side view diagram of 50% compression recovery without compression. 210. Top view of alloying 220. Top view of microskeleton encapsulation. 230. Filled top view diagram, 240. Top view of the sandwich structure; 301. Limiting bead; 302. Limiting post, 303. Limiting grille, 304. Homogeneous interlayer confinement zone, 305. Homogeneous confinement region 310. Side view diagram of ball-type limit switch. 311. Top view of the ball-type fixed point limiter. 312. Top view diagram of spherical scattering limit. 320. Side view diagram of column-type limit switch. 321. Top view of column-type fixed point limiting diagram. 330. Side view diagram of a grid-type limiting device. 331. Top view of the grid-type limit switch. 340. Homogeneous sandwich-type limiting side view diagram. 341. Top view of the sandwich-type four-dimensional limiting mechanism. 342. Top view of the sandwich-type side-limiting structure. 350. Schematic diagram of the side view showing the limitation of homogeneous heterogeneous porosity. 351. Schematic diagram of homogeneous heterogeneous pore size limiting side view. 352. Top view of the confinement of homogeneous heterogeneous structures. 401. Polymer-high thermal conductivity filler scattered heat conduction channels, 402. Linear heat conduction channel for heat dissipation film. 403. The heat dissipation film improves the heat conduction channels between the upper and lower layers. 404. Fully conductive heat conduction channel. 405. Sandwiched heat conduction channel, 501. Bottom layer, 502. Compression limiting interlayer, 503. Elastic reinforced sandwich layer, 504. Top floor, 601. Heat dissipation devices, 602. Heat source devices, 603. Chip packaging layer and heat sink connection face. Detailed Implementation

Example 1

[0037] like Figure 1 As shown, a compressible and resilient porous composite thermal interface material includes a porous thermally conductive skeleton 1, a compression and resilience enhancement mechanism 2, and a compression limiting device 3.

[0038] 1.1 Using a porous thermally conductive skeleton 1 as the base, a compression and rebound enhancement mechanism 2 is used to elastically enhance the porous thermally conductive skeleton 1, and a compression limiting device 3 is arranged in the base.

[0039] 1.2 The porous thermally conductive framework 1 is a porous material with a thermal conductivity of not less than 30 W / mK in its dense form and a certain degree of ductility. It includes, but is not limited to, at least one of foamed iron, foamed aluminum, foamed copper, foamed silver, and their alloys.

[0040] 1.3, such as Figure 2 As shown, the compression rebound enhancement mechanism 2 is to enhance the compression rebound of the porous thermally conductive skeleton 1, including but not limited to at least one of alloying, micro-skeleton coating, micro-particle filling, and sandwich; the material used in the compression rebound enhancement mechanism 2 is capable of maintaining rebound performance at temperatures below 60 degrees Celsius, including but not limited to any one of silicone, polyurethane, spring steel, copper for springs and its plating.

[0041] Its function is to enhance the elasticity of the porous thermally conductive skeleton 1, so that it can repeatedly fill the gaps between interfaces.

[0042] 1.4, such as Figure 3 As shown, the compression limiting device 3 is one or more of the following: Based on their distribution pattern, they can be evenly distributed at a certain distance, scattered randomly at multiple points, curled at the edges and corners, strip-shaped, or embedded sandwich-shaped. Among them, the edge strip can be a single side edge, double side edge, four-sided edge, or grid; Based on their microscopic shape, they can be spherical, columnar, solid lines, or porous foam states, among which... Spherical or columnar, it is a high thermal conductivity material, and can be made of copper, silver, etc., in bead or columnar structure. The diameter of the bead particles and the height of the column are not less than 1 / 8 of the overall thickness. The strip shape is made of the same material as the porous thermally conductive framework 1. If the edges are rolled up or the core is embedded, the porosity and pore size can be the same; If they are connected to each other on the same plane, it is a higher density form of the material, which is one of the following: a non-porous solid material with lower porosity, smaller pore size, and lower thickness.

[0043] The purpose is to prevent excessive compression that could cause the microstructure to be unable to recover.

Example 2

[0044] The porous thermally conductive skeleton 1 has its upper and lower surfaces uniformly filled with supplementary thermally conductive filler 4, which is composed of a thickener and high thermal conductivity particulate filler.

[0045] The thickener is generally either dimethylsilane or purified water.

[0046] The high thermal conductivity microparticle filler is a particle or droplet with a thermal conductivity of not less than 30 W / mK and not less than the thermal conductivity of the porous thermally conductive skeleton 1 after compression by 30%. It includes at least one of the following materials: metal powders such as aluminum, copper, and silver; nitrides such as aluminum nitride and boron nitride; oxides such as alumina, zinc oxide, and beryllium oxide; carbide materials such as silicon carbide and boron carbide; and highly oriented carbon materials such as graphite, diamond, and carbon nanotubes.

[0047] The purpose of adding thermally conductive filler is to improve the surface filling rate of high thermal conductivity materials, while thickener is mainly used to hold thermally conductive microparticle filler particles together during product production to prevent them from scattering and causing dust pollution. After the first few thermal cycles, the thickener evaporates completely to prevent its extremely low thermal conductivity from affecting the overall thermal conductivity.

Example 3

[0048] like Figure 5 As shown, the aforementioned compressible and resilient porous composite thermal interface material is sheet-like and composed of multiple layers. The top layer 504 and the bottom layer 501 form a porous thermally conductive framework 1. The intermediate layers consist of a compression-limiting interlayer 503 and an elastically reinforcing interlayer 504, which are bonded together with a high-temperature resistant adhesive. The elastically reinforcing interlayer 502 also serves as an adhesive between the upper and lower layers. Supplementary thermally conductive filler 4 is coated onto the surfaces of the top layer 504 and the bottom layer 501.

[0049] The compression limiting interlayer 503 and the porous heat-conducting skeleton 1 are made of the same material and are distributed in any of the following ways: the compression limiting interlayer (502) surrounds the elastic reinforcing interlayer (504) on all four sides, or is located on both sides of the elastic reinforcing interlayer (504).

[0050] The elastic reinforcing interlayer 504 is any of polyurethane or silicone, and its distribution form is any of the following: applied to the corresponding inner layers of the top layer 504 and the bottom layer 501, or placed as an independent sheet between the top layer 504 and the bottom layer 501.

[0051] Because the middle layer is separated by a low thermal conductivity elastically reinforced 504 interlayer, the upper limit of thermal conductivity depends entirely on the proportion and thermal conductivity of the material used as the compression-limiting interlayer. Since the limiting layer accounts for 30% to 50%, its upper limit of thermal conductivity is also 30% to 50%.

[0052] Its advantages are that it is simple and easy to produce.

Example 4

[0053] As described in Example 3, the above-mentioned compressible and resilient porous composite thermal interface material consists of two layers connected together by a high-temperature resistant adhesive. The top layer 504 and the bottom layer 501 form a porous thermally conductive framework 1. Compression limiting devices 3 are distributed around or on both sides of the top layer 504 and the bottom layer 501, and are homogeneous materials with varying porosities or pore sizes within the porous thermally conductive framework 1. The compression and resilience enhancement mechanism 2 is distributed between the top layer 504 and the bottom layer 501, and is applied to the corresponding inner layers of the top layer 504 and the bottom layer 501.

[0054] The advantage of this method is that it is easier to produce and can make the thickness thinner.

Example 5

[0055] like Figure 2 As shown, the above-mentioned compressible and resilient porous composite thermal interface material is a single-layer sheet. Its compression and resilience enhancement mechanism 2 is a micro-scaffold type 220. The compression and resilience material wraps the pores connecting the skeleton in the porous thermal conductive skeleton body 1. The upper and lower surfaces of the porous thermal conductive skeleton body 1 do not contain the compression and resilience enhancement mechanism 2 material with low thermal conductivity.

[0056] Its advantages are that the flat shape can be cut arbitrarily and the thickness can be made very thin. Its disadvantages are that it is difficult to produce and causes a lot of pollution.

Example 6

[0057] The compressible and resilient porous composite thermal interface material according to claim 1 or 2 is characterized in that it is a single-layer sheet, and the porous thermally conductive skeleton 1, the compression and resilience enhancement mechanism 2, and the compression limiting device 3 are all made of any one of high elastic alloys of iron or copper.

[0058] The advantage is that the resulting porous composite thermal interface material is resistant to high temperatures. Among them, iron alloys, such as spring steel, are relatively inexpensive, and their thermal conductivity can be easily achieved to >20w / mK, which is far superior to the current mainstream thermal interface materials.

[0059] Due to its high hardness, steel is not suitable for applications using heat sources and heat dissipation materials such as copper and aluminum.

Example 7

[0060] like Figure 6 As shown, a heat dissipation device and a heat source device thermal interface structure are characterized in that the porous thermally conductive skeleton 1 and the heat source device 602 or the heat dissipation device 601 are integrated. The surface of the connection end face of the heat source device 602 or the heat dissipation device 601 is porousened to form a porous thermally conductive skeleton 1. According to embodiment 1 or 2, a corresponding compression rebound enhancement mechanism 2 and a compression limiting device 3 are set, and a supplementary thermally conductive filler 4 is filled in.

[0061] The heat source device 602 or heat sink device 601 includes, but is not limited to, any one of the following: heat pipe end, heat sink fin and hot end connection face, connection part between the inner side of the back shell of a heat dissipation device such as a mobile phone, tablet computer, or LCD display and the heat-generating component inside the casing, water-cooled heat conduction block connection face, chip encapsulation layer and heat sink connection face 603, socket insertion clamping face, laser and heat sink connection face, and hot and cold interface heat transfer face of a hot melt extruder.

[0062] Beneficial effects: It can minimize the amount of thermal interface layer while improving the thermal conductivity of the thermal interface layer.

Claims

1. A compressible and resilient porous composite thermal interface material, comprising a porous thermally conductive framework (1), a compression and resilience enhancement mechanism (2), and a compression limiting device (3), characterized in that: Using a porous thermally conductive skeleton (1) as the matrix, a compression and rebound enhancement mechanism (2) is used to elastically enhance the porous thermally conductive skeleton (1), and a compression limiting device (3) is arranged in the matrix. The porous thermally conductive skeleton (1) is a porous material with a thermal conductivity of not less than 30w / mK in its dense form and a certain degree of ductility, including but not limited to foamed iron, foamed aluminum, foamed copper, foamed silver and at least one of their alloys; The compression and springback enhancement mechanism (2) is to enhance the compression and springback of the porous thermally conductive skeleton (1), including but not limited to at least one of alloying, micro-skeleton coating, micro-particle filling, and sandwich; The compression rebound enhancement mechanism (2) uses materials that can maintain rebound performance at temperatures below 60 degrees Celsius, including but not limited to any one of silicone, polyurethane, spring steel, copper for springs and their plating.

2. The compressible and resilient porous composite thermal interface material according to claim 1, characterized in that, The porous thermally conductive skeleton (1) is uniformly filled with supplementary thermally conductive filler (4) on its upper and lower surfaces. The supplementary thermally conductive filler (4) is composed of thickener and high thermal conductivity particulate filler. The thickener is generally either dimethylsilane or purified water; The high thermal conductivity microparticle filler is a particle or droplet with a thermal conductivity of not less than 30 W / mK and not less than the thermal conductivity of the porous thermally conductive skeleton (1) after compression by 30%, including at least one of the following materials: Metal powders such as aluminum, copper, and silver; nitrides such as aluminum nitride and boron nitride; oxides such as aluminum oxide, zinc oxide, and beryllium oxide; carbide materials such as silicon carbide and boron carbide; and highly oriented carbon materials such as graphite, diamond, and carbon nanotubes.

3. The compressible and resilient porous composite thermal interface material according to claim 1 or 2, characterized in that, It is sheet-like and composed of multiple layers. The top layer (504) and the bottom layer (501) are porous thermally conductive skeletons (1). The middle interlayer consists of a compression limiting interlayer (503) and an elastic reinforcing interlayer (504). The interlayers are connected together with high-temperature resistant adhesive. The elastic reinforcing interlayer (502) can also serve as an adhesive between the upper and lower layers. A supplementary thermally conductive filler (4) is applied to the surface of the top layer (504) and the bottom layer (501). The compression limiting interlayer (503) and the porous heat-conducting skeleton (1) are made of the same material and are distributed in any of the following ways: the compression limiting interlayer (502) surrounds the elastic reinforcing interlayer (504) on all four sides, or is located on both sides of the elastic reinforcing interlayer (504). The elastic reinforcing interlayer (504) is either polyurethane or silicone, and is distributed in any of the following ways: applied to the corresponding inner layers of the top layer (504) and the bottom layer (501), or placed as an independent sheet between the top layer (504) and the bottom layer (501).

4. The compressible and resilient porous composite thermal interface material according to claim 3, characterized in that, It consists of two layers connected together by a high-temperature resistant adhesive. The top layer (504) and the bottom layer (501) are porous thermally conductive skeletons (1). The compression limiting devices (3) are distributed around or on both sides of the top layer (504) and the bottom layer (501), and are homogeneous materials with different porosities or different pore sizes of the porous thermally conductive skeletons (1). The compression and rebound enhancement mechanism (2) is distributed between the top layer (504) and the bottom layer (501), respectively, and applied to the corresponding inner layers of the top layer (504) and the bottom layer (501).

5. The compressible and resilient porous composite thermal interface material according to claim 1 or 2, characterized in that, It is a single-layer sheet, and its compression rebound enhancement mechanism (2) is a micro-scaffold type (220). The compression rebound material wraps the pores in the porous thermally conductive skeleton (1) and the upper and lower surfaces of the porous thermally conductive skeleton (1) do not contain the compression rebound enhancement mechanism (2) material with low thermal conductivity.

6. The compressible and resilient porous composite thermal interface material according to claim 1 or 2, characterized in that, It is a single-layer sheet, and the porous thermally conductive skeleton (1), the compression rebound enhancement mechanism (2), and the compression limiting device (3) are all of any one of the high elasticity alloys of iron or copper.

7. A thermal interface structure for a heat dissipation device and a heat source device, characterized in that, The porous thermally conductive skeleton (1) and the heat source device (602) or heat dissipation device (601) are integrated. The surface of the connection end face of the heat source device (602) or heat dissipation device (601) is porous to form a porous thermally conductive skeleton (1). According to claim 1 or 2, a corresponding compression rebound enhancement mechanism (2) and compression limiting device (3) are provided, and a supplementary thermally conductive filler (4) is filled in. The heat source device (602) or heat sink device (601) includes, but is not limited to, any one of the following: heat pipe end, heat sink fin and hot end connection face, the connection part between the inner side of the back shell of a heat dissipation device such as a mobile phone, tablet computer, or LCD display and the heat-generating component inside the casing, the connection face of a water-cooled heat conduction block, the connection face between the chip encapsulation layer and the heat sink (603), the socket insertion clamping face, the connection face between the laser and the heat sink, and the hot and cold junction heat transfer face of a hot melt extruder.

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