Composite heat conduction substrate based on pyrolytic graphite and manufacturing method thereof

Abstract

The invention belongs to the field of heat conduction substrates, and particularly discloses a pyrolytic graphite-based composite heat conduction substrate and a manufacturing method thereof.The pyrolytic graphite-based composite heat conduction substrate comprises a metal shell, a heat transfer cover plate and a pyrolytic graphite flake, one side of the metal shell is provided with a mounting groove for mounting components, and the bottom of the mounting groove is provided with a groove matched with the pyrolytic graphite flake in an embedded mode; the heat transfer cover plate is fixedly connected to the opening of the groove; and a heat exchange surface and radiating fins are arranged on the other side of the metal shell. According to the composite heat conduction substrate with the integral structure formed by the metal shell, the heat transfer cover plate and the pyrolytic graphite sheet, the heating component in the metal shell can realize heat transfer and heat expansion through the heat transfer cover plate and the pyrolytic graphite sheet, and further realizes heat dissipation through the heat exchange surface and the heat dissipation fins, so that the composite heat conduction substrate is simple in structure, easy to manufacture and low in cost. Meanwhile, due to the fact that the formed overall structure is high in strength, the beneficial effects that the structure is not prone to being affected by the application environment, suitable for being used under the high-overload working condition and capable of effectively conducting uniform-temperature heat dissipation can be achieved.

Description

Technical Field

[0001] The present application belongs to the field of thermally conductive substrates, and more specifically, relates to a composite thermally conductive substrate based on pyrolytic graphite and a method for manufacturing the same. Background Art

[0002] With the development of the electronics industry, the performance of components has been greatly improved, with high integration, reduced size and high power. This also leads to heat concentration and excessively high local temperatures when the components are working, which seriously affects the normal operation and performance of the components.

[0003] Missile-borne electronic products often bear a greater amount of data processing due to the complexity of the working environment, and require faster data processing speeds. Correspondingly, the heat consumption of electronic products will increase dramatically. However, missile-borne products are often subject to space limitations and environmental conditions, making it difficult to apply air cooling and liquid cooling, which leads to higher and higher requirements for the heat dissipation performance of electronic equipment. For such problems of concentrated and uneven heat distribution, the traditional radiator structure can no longer meet the needs of increasingly high-power equipment systems.

[0004] In the related technology, electronic products mainly transfer and dissipate concentrated heat through a vapor chamber. Phase change vapor chamber is a commonly used vapor chamber, including heat pipes and flat heat pipes (VC), but the refined process control of heat pipes and flat heat pipes makes product manufacturing more difficult and costly, and the heat sources of missile-borne electronic modules are mostly various types of heat-generating chips. The specific location of the chip is mainly determined by the circuit design. It is difficult to arrange the heat source in the high thermal conductivity area of ​​the vapor chamber. At the same time, under high overload acceleration conditions, the capillary suction force of the phase change vapor chamber is difficult to overcome the influence of acceleration, thereby interrupting the liquid-gas-liquid phase change circuit of the internal working fluid, resulting in the deterioration or even failure of the heat dissipation performance of the phase change vapor chamber. That is, the thermal conductivity of the phase change vapor chamber is easily affected by the nonlinear factors such as the heat source power, the heat sink temperature, and the overload acceleration, resulting in poor uniform heat dissipation effect, and it cannot be used for heat dissipation of missile-borne electronic equipment. Summary of the invention

[0005] In response to the defects of the prior art, the present application provides a composite thermally conductive substrate based on pyrolytic graphite and a method for manufacturing the same, aiming to solve the problems that the existing phase change heat sink is difficult to process, has high manufacturing cost, is easily affected by the application environment and is therefore not suitable for high overload conditions.

[0006] The present application provides a composite heat-conducting substrate based on pyrolytic graphite, which specifically includes a metal shell, a heat transfer cover plate and a pyrolytic graphite sheet. One side of the metal shell is provided with an installation groove for installing components, and the bottom of the installation groove is provided with a groove adapted to be embedded in the pyrolytic graphite sheet, and the heat transfer cover plate is fixedly connected to the opening of the groove; the other side of the metal shell is provided with a heat exchange surface and heat dissipation fins.

[0007] Through the above technical scheme conceived by the present application, compared with the prior art, since the present application is a composite heat-conducting substrate with an integral structure composed of a metal shell, a heat transfer cover plate and a pyrolytic graphite sheet, the heat-generating components inside the metal shell can achieve heat transfer and heat expansion through the heat transfer cover plate and the pyrolytic graphite sheet, and then achieve heat dissipation through the heat exchange surface and the heat dissipation fins. The structure is simple and easy to manufacture. At the same time, due to the high strength of the overall structure formed, it can be less susceptible to the influence of the application environment, is suitable for use under high overload conditions, can be used for the heat dissipation of missile-borne electronic equipment, and effectively achieve the beneficial effect of uniform temperature heat dissipation.

[0008] As a further preference, a plurality of enhanced thermal conductive pillars distributed in an array are arranged in the groove, the enhanced thermal conductive pillars are perpendicular to the bottom surface of the groove, and positioning holes for the enhanced thermal conductive pillars to pass through are opened on the pyrolytic graphite sheet.

[0009] By adopting the above technical solution, the pyrolytic graphite sheet is installed in the groove, and the heat-reinforced conductive pillar passes through the positioning hole on the pyrolytic graphite sheet, thereby improving the installation stability of the pyrolytic graphite sheet, and the pyrolytic graphite sheet is in uniform contact with the metal shell, thereby improving the thermal conductivity and heat expansion effect.

[0010] As a further preference, the top of the enhanced heat conduction support is in contact with the bottom of the heat transfer cover plate.

[0011] By adopting the above technical solution, the enhanced heat-conducting pillars can provide a certain supporting effect on the heat transfer cover plate, thereby ensuring the overall mechanical strength of the composite heat-conducting substrate and improving the pressure resistance of the composite heat-conducting substrate.

[0012] As a further preference, a step groove adapted to be embedded with the heat transfer cover plate is further provided at the bottom of the installation groove, and the groove is located in the middle of the step groove.

[0013] By adopting the above technical solution, the heat transfer cover plate is stably arranged in the step groove, the heat transfer cover plate matches the step groove of the metal shell, and satisfies the interference fit installation. Through vacuum pressure diffusion welding, it is ensured that the pyrolytic graphite sheet, the metal shell and the heat transfer cover plate are tightly fitted.

[0014] As a further preference, a heat transfer boss is provided on a side of the heat transfer cover plate away from the groove, and the heat transfer boss is in contact with the heat-generating component in the mounting groove.

[0015] By adopting the above technical solution, the heat-generating components in the mounting grooves are connected to the heat transfer bosses and corresponding thermally conductive pads, and the high thermal conductivity pyrolytic graphite built between the metal shell and the heat transfer cover plate is used to achieve rapid and uniform heat diffusion in the plane, and the heat transfer in the vertical direction of the thermally conductive substrate is enhanced by strengthening the thermally conductive pillars, thereby achieving the needs of efficient heat transfer and heat dissipation.

[0016] As a further preference, the surface of the pyrolytic graphite sheet is provided with a surface metallized protective layer.

[0017] By adopting the above technical solution, the protective layer can protect the pyrolytic graphite sheet and prevent it from chemically reacting with the metal shell and the heat transfer cover plate at high temperature.

[0018] As a further preference, the enhanced heat-conducting support pillar is made of heat-conducting material.

[0019] By adopting the above technical solution, the enhanced heat-conducting pillars can achieve heat conduction and enhance the thermal conductivity of the heat-conducting substrate of the present application in a direction perpendicular to the groove surface.

[0020] As a further preference, the metal shell and the heat transfer cover plate are both made of aluminum alloy material.

[0021] By adopting the above technical solution, the aluminum alloy metal shell and the aluminum alloy heat transfer cover plate are welded to ensure the thermal conductivity and mechanical properties of the formed heat-conducting substrate.

[0022] The present application also provides a method for manufacturing a composite thermally conductive substrate, which is used to manufacture the above-mentioned composite thermally conductive substrate based on pyrolytic graphite, comprising the following steps: S1, sequentially installing the pyrolytic graphite sheet and the heat transfer cover plate in the metal housing; S2, vacuuming the groove; S3, welding the heat transfer cover plate and the metal shell by using a vacuum pressure diffusion welding process; S4, vacuuming the groove again; S5. The groove is sealed to form a closed cavity inside, thereby completing the production of the composite thermal conductive substrate.

[0023] As further preferred, in the step S2, an exhaust port connected to the groove and used for vacuuming the groove is opened on the metal shell.

[0024] By adopting the above technical solution, the groove can be easily vacuumed through the exhaust port to avoid bulging problems when welding the heat transfer cover plate, so that the atoms of the pyrolytic graphite sheet, the metal shell and the heat transfer cover plate diffuse with each other and fit closely.

[0025] In general, the above technical solutions conceived by this application have the following technical advantages compared with the prior art: 1. The composite heat-conducting substrate of the present application is composed of a metal shell, a heat transfer cover plate and a pyrolytic graphite sheet as an integral structure. Compared with the existing solid shell, the heat-generating components inside the metal shell of the present application can achieve heat transfer and heat expansion through the heat transfer cover plate and the pyrolytic graphite sheet, and then achieve heat dissipation through the heat exchange surface and the heat dissipation fins, which solves the problem that the local temperature is too high due to heat concentration and the components cannot operate normally. The structure is simple and easy to manufacture. At the same time, due to the high strength of the overall structure formed by it, it can achieve the beneficial effect of not being easily affected by the application environment, suitable for use under high overload conditions, and effectively achieving uniform temperature heat dissipation.

[0026] 2. In the present application, the pyrolytic graphite sheet is installed in the groove, and the enhanced heat-conducting pillar passes through the positioning hole on the pyrolytic graphite sheet, thereby improving the installation stability of the pyrolytic graphite sheet, and the pyrolytic graphite sheet is in uniform contact with the metal shell, thereby improving the heat conduction and heat expansion effect, and the enhanced heat-conducting pillar can play a certain supporting effect on the heat transfer cover plate, thereby ensuring the overall mechanical strength of the composite heat-conducting substrate, improving the pressure resistance of the composite heat-conducting substrate, and at the same time, the enhanced heat-conducting pillar can realize the conduction of heat, and enhance the thermal conductivity of the heat-conducting substrate of the present application in the direction perpendicular to the groove surface.

[0027] 3. The present application adopts vacuum pressure diffusion welding process to weld the heat transfer cover plate and the metal shell, and to weld the aluminum alloy metal shell and the aluminum alloy heat transfer cover plate to ensure the structural strength, welding strength and thermal conductivity of the formed heat transfer substrate, and to ensure the bonding strength between the pyrolytic graphite sheet, the metal shell and the heat transfer shell, so that the heat transfer substrate can be suitable for high overload conditions.

[0028] 4. The composite thermally conductive substrate based on pyrolytic graphite of the present application relies on the heat transfer process of high thermal conductivity pyrolytic graphite. The composite thermally conductive substrate has the ability to transfer large heat flow under small temperature difference. At the same time, the heat transfer of the composite thermally conductive substrate does not require consumption of other forms of energy, and there are no mechanical moving parts. It is reliable in operation and compact in structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the composite thermally conductive substrate provided in an embodiment of the present application; Figure 2 This is a schematic diagram of the overall structure of the metal shell provided in the embodiment of the present application from a first perspective; Figure 3 is a schematic diagram of the overall structure of the metal shell provided by an embodiment of the present application from a second viewing angle; Figure 4 is a schematic diagram of the overall structure of the heat transfer cover plate provided in an embodiment of the present application; Figure 5 It is a schematic diagram of the overall structure of the pyrolytic graphite sheet provided in the embodiment of the present application.

[0030] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1. Metal shell; 101. Enhanced heat conduction support; 102. Groove; 103. Step groove; 104. Mounting groove; 105. Heat exchange surface; 106. Heat dissipation fin; 2. Heat transfer cover plate; 201. Heat transfer boss; 202. Interference fit surface; 3. Pyrolytic graphite sheet; 301. Positioning hole. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] The thermal conductivity of the existing phase change heat spreader is affected by the nonlinearity of the heat source power, heat sink temperature, and overload acceleration, and cannot optimally match the application environment and application boundary where the power of the electronic module and the heat sink temperature change dramatically during missile flight, and the overload acceleration is completely inconsistent with the ground gravity state. Therefore, this application proposes a composite thermal conductive substrate based on pyrolytic graphite, which has the characteristics of good heat transfer performance and is not affected by the external environment and heat load characteristics, and can meet the heat dissipation requirements of high-power electronic modules in missile-loaded high overload environments.

[0033] Reference Figure 1-5The present application discloses a composite heat-conducting substrate based on pyrolytic graphite, comprising a metal shell 1, a heat transfer cover plate 2 and a pyrolytic graphite sheet 3, wherein the metal shell 1 and the heat transfer cover plate 2 are both made of aluminum alloy material, providing structural support and environmental adaptability protection, process adaptability transition and partial heat conduction and heat transfer functions, wherein the interlayer is the pyrolytic graphite sheet 3, which is the main heat transfer functional layer and has the function of rapid heat transfer and heat expansion; an installation groove 104 for installing components is provided on the inner side of the metal shell 1, a groove 102 is provided at the bottom of the installation groove 104, the groove 102 is embedded and adapted with the pyrolytic graphite sheet 3, the pyrolytic graphite sheet 3 is installed in the groove 102 and the pyrolytic graphite sheet 3 is in contact with the inner wall of the groove 102, and the pyrolytic graphite sheet 3 is flush with the opening surface of the groove 102 The heat transfer cover plate 2 is fixedly connected to the opening of the groove 102. The side of the heat transfer cover plate 2 close to the pyrolytic graphite sheet 3 is required to be smooth and clean, with good flatness and low roughness, so as to reduce the contact thermal resistance and achieve a good heat conduction effect. The heat of the heat-generating components is conducted and diffused through the heat transfer cover plate 2 and the pyrolytic graphite sheet 3. The outer side of the metal shell 1 is provided with a heat exchange surface 105 and a heat dissipation fin 106 to achieve uniform temperature heat dissipation; the heat dissipation fin 106 is used for air cooling or natural convection heat dissipation, which achieves the effect of heat convection heat dissipation. The heat exchange surface 105 is provided with at least one point, which has good flatness and low roughness, so as to reduce the contact thermal resistance. Through the connection between the surface and the external interface, heat conduction occurs on the cold conduction surface, which achieves the effect of conduction heat dissipation. The inner sides of the metal shell 1 and the heat transfer cover plate 2 are fixedly connected and provided with threaded mounting holes so that the composite heat conductive substrate can be installed and used.

[0034] Among them, pyrolytic graphite sheets are pyrolytic carbon with a higher crystal orientation that is deposited by chemical vapor deposition under certain furnace pressure and high temperature conditions. It is an anisotropic ultra-high thermal conductivity material with a microstructure close to that of graphite crystals. It has the characteristics of high density, high purity, dense surface, no pores, easy machining, high thermal conductivity, small thermal expansion coefficient, and excellent thermal shock resistance.

[0035] In this embodiment, the surface of the pyrolytic graphite sheet 3 is provided with a surface metallized protective layer. Since the pyrolytic graphite sheet 3 will react chemically with the aluminum-based material at high temperature to generate Al 4 C 3 For this purpose, the surface of the pyrolytic graphite sheet 3 is coated with metal materials such as Cu, Ni, Ti, etc. to form a protective layer for protection.

[0036] Specifically, the groove 102 is provided with a plurality of enhanced heat-conducting pillars 101 distributed in an array. In this embodiment, a plurality of enhanced heat-conducting pillars 101 are provided, and the plurality of enhanced heat-conducting pillars 101 are perpendicular to the bottom surface of the groove 102. A positioning hole 301 for the enhanced heat-conducting pillars 101 is provided on the pyrolytic graphite sheet 3. After the pyrolytic graphite sheet 3 is installed, the pyrolytic graphite sheet 3 is more stable and the contact with the metal shell 1 is uniform, which is used to increase the thermal conductivity of the composite heat-conducting substrate in the vertical direction and improve the heat conduction and heat expansion effect of the heat-conducting substrate perpendicular to the groove 102 surface. The enhanced heat-conducting pillars 101 are processed as an integrated whole with the metal shell 1, and other metal materials that enhance heat conduction can also be combined with the metal shell 1 by welding or the like to realize heat conduction and enhance the thermal conductivity of the heat-conducting substrate in the vertical direction of the present application. In actual processing, the enhanced heat-conducting pillars 101 can be set in different shapes, sizes and spacing sizes of their arrangement, and can meet the heat dissipation requirements of various heat source powers and their different distributions in the plane by optimizing the combination of various sizes.

[0037] In this embodiment, the tops of the multiple enhanced heat-conducting pillars 101 are all in contact with the bottom of the heat transfer cover plate 2, and the enhanced heat-conducting pillars 101 can play a certain supporting effect on the heat transfer cover plate 2, thereby ensuring the overall mechanical strength of the composite heat-conducting substrate and improving the pressure resistance of the composite heat-conducting substrate; and the enhanced heat-conducting pillars 101 are made of heat-conducting materials, and the heat conduction can be achieved by enhancing the heat-conducting pillars 101, thereby enhancing the heat conductivity of the heat-conducting substrate of this application in the direction perpendicular to the groove 102 surface. In another feasible embodiment, the top of the enhanced heat-conducting pillar 101 is provided with an integrally formed positioning protrusion, and the heat transfer cover plate 2 is provided with a through hole that is plugged and adapted to the positioning protrusion. Multiple enhanced heat-conducting pillars 101 and the heat transfer cover plate 2 constitute a longitudinal heat-conducting structure, that is, a heat-conducting structure perpendicular to the groove 102 surface, which enhances the longitudinal thermal conductivity of the substrate, improves the overall heat dissipation capacity and temperature resistance, and the longitudinal heat-conducting structure array is dispersedly arranged, and a "honeycomb" structure is formed inside the metal shell 1, which can improve the bearing capacity of the substrate. The array-distributed longitudinal heat-conducting structure forms a constraint between the pyrolytic graphite and the aluminum alloy, which is beneficial to strengthening the mechanical bonding between the pyrolytic graphite sheet 3 and the aluminum alloy. The metal shell 1 and the heat transfer cover plate 2 form a micro-connection, similar to a honeycomb, which can greatly improve the mechanical properties of the composite heat-conducting substrate.

[0038] Furthermore, the bottom of the installation groove 104 is also provided with a step groove 103 which is adapted to be embedded in the heat transfer cover plate 2. The groove 102 is located in the middle of the step groove 103. The heat transfer cover plate 2 is stably arranged in the step groove 103. The heat transfer cover plate 2 matches the step groove 103 of the metal shell 1 and is installed by interference fit. The heat transfer cover plate 2 is fixedly connected to the metal shell 1 by welding. After welding, the gap is filled to ensure that the pyrolytic graphite sheet 3, the metal shell 1 and the heat transfer cover plate 2 are tightly fitted. If the positioning protrusion on the enhanced heat conduction support 101 is inserted into the through hole on the heat transfer cover plate 2, the gap between the positioning protrusion and the through hole needs to be welded during welding. A heat transfer boss 201 is provided on the side of the heat transfer cover plate 2 away from the groove 102. The heat transfer boss 201 is combined with the heat conductive adhesive pad to fit the heat generating components in the installation groove 104. The heat generated by the components is conducted through the heat transfer boss 201 to meet the heat transfer and heat dissipation requirements of the heat generating components.

[0039] The present application also discloses a method for manufacturing a composite thermally conductive substrate, which is used to manufacture the composite thermally conductive substrate based on pyrolytic graphite, comprising the following steps: S1. Install the pyrolytic graphite sheet 3 and the heat transfer cover plate 2 in the metal shell 1 in sequence; the pyrolytic graphite sheet 3 is located in the groove 102, the enhanced heat conduction pillar 101 passes through the pyrolytic graphite sheet 3, the pyrolytic graphite sheet 3 is in contact with the inner wall of the groove 102, the heat transfer cover plate 2 is located in the step groove 103, and the interference fit surface 202 of the heat transfer cover plate 2 is in contact with the inner wall of the step groove 103.

[0040] S2. Vacuum the groove 102. An exhaust port connected to the groove 102 is provided on the metal shell 1. The exhaust port can be used to facilitate vacuuming of the groove 102 to avoid bulging caused by the gas in the groove 102 during welding of the heat transfer cover plate 2, so that the atoms of the pyrolytic graphite sheet 3, the metal shell 1 and the heat transfer cover plate 2 diffuse with each other and fit closely.

[0041] S3, the heat transfer cover plate 2 and the metal shell 1 are welded by vacuum pressure diffusion welding process; due to the poor wettability of the pyrolytic graphite sheet 3, holes will be formed at the interface between the aluminum-based shell, the cover plate and the pyrolytic graphite sheet 3. At the same time, considering the large difference in thermal expansion coefficients between aluminum and graphite, there will be a problem of mismatching thermal expansion coefficients at the interface between the metal shell 1, the heat transfer cover plate 2 and the pyrolytic graphite sheet 3. In order to solve the above problems, the pyrolytic graphite sheet 3 is subjected to surface metallization treatment. At the same time, during welding, the outer shape characteristics of the heat transfer cover plate 2 match the step groove 103 of the metal shell 1, and the gap is filled by interference fit welding to ensure that the pyrolytic graphite sheet 3 is tightly fitted with the metal shell 1 and the heat transfer cover plate 2; the structural strength and welding strength are ensured by welding the aluminum alloy metal shell 1 and the aluminum alloy heat transfer cover plate 2, thereby ensuring the thermal conductivity and mechanical properties of the composite heat conductive substrate. After packaging, the substrate surface is flat, sealed and waterproof and dustproof, and the reliability of the heat spreader is further improved.

[0042] S4, vacuuming the groove 102 again; with high temperature and long-term heating, some gas remaining in the pyrolytic graphite layer will escape, and the residual gas needs to be discharged a second time to ensure the welding effect.

[0043] S5. The groove 102 is sealed. After the secondary exhaust, the exhaust port is sealed by a traceless sealing method to ensure the strength of the seal and the flatness of the processing. The sealing process of the groove 102 is completed to form a closed cavity inside, and the production of the composite thermal conductive substrate is completed.

[0044] The present application is a composite heat-conducting substrate with an integral structure consisting of a metal shell 1, a heat transfer cover plate 2 and a pyrolytic graphite sheet 3. The heat-generating components inside the metal shell 1 can achieve heat transfer and heat expansion through the heat transfer cover plate 2 and the pyrolytic graphite sheet 3, and then achieve heat dissipation through the heat exchange surface 105 and the heat dissipation fins 106. It has the characteristics of good heat transfer performance and is not affected by the external environment and heat load characteristics. At the same time, vacuum pressure diffusion welding is used to fill the gap through interference fit welding between the heat transfer cover plate 2 and the metal shell 1 to ensure the bonding strength of the pyrolytic graphite and the aluminum-based structure, thereby ensuring that the composite heat-conducting substrate will not be damaged under high overload or reverse gravity conditions. Since the overall structural strength formed by it is relatively high and it is not easily affected by the application environment, it is suitable for use under high overload conditions and effectively performs uniform temperature heat dissipation. Compared with the existing solid shell, by arranging the pyrolytic graphite sheet 3 in the metal shell 1, a temperature equalization effect is achieved, which solves the problem of excessive local temperature due to heat concentration and inability of components to operate normally; compared with heat pipes and phase change heat spreaders, the pyrolytic graphite sheet 3 used in this application will not be affected by factors such as gravity and high overload, so that the temperature equalization effect is more stable and reliable under the missile load environment; by arranging the enhanced thermal conductive support 101 in the groove 102, compared with the traditional phase change heat spreader, the thermal conductivity in the vertical direction is significantly enhanced, and the pressure resistance of the composite thermal conductive substrate is also enhanced.

[0045] This application adopts a semi-physical measurement method to define and measure the equivalent heat transfer coefficient and internal contact thermal resistance of the composite thermal conductive substrate. The specific method is: use heat transfer simulation software to establish a reference sample model, simulate its temperature field, and compare the simulated temperature at the measuring point with the measured value to verify the correctness of the simulation model; then adjust the thermal conductivity and contact thermal resistance of the simulation model material respectively, re-simulate the calculation, compare the calculated temperature value at the measuring point with the measured value of the composite thermal conductive substrate sample, and continuously modify the thermal conductivity and contact thermal resistance of the simulation model. After multiple rounds of simulation iterations, until the simulation results and the measured results of the heat spreader measuring point meet the error requirements, the thermal conductivity and contact thermal resistance of the reference model at this time are defined as the equivalent heat transfer coefficient and internal contact thermal resistance of the composite thermal conductive substrate.

[0046] In one embodiment, through simulation iteration and actual measurement comparison, it is determined that the equivalent thermal conductivity of the composite thermal conductive substrate is 450W / M·K, and the internal contact thermal resistance is 2×10-5K·m 2 / W, indicating that the effective thermal conductivity of the composite thermal conductive substrate is much higher than that of the aluminum alloy module, and the contact thermal resistance is small, and the internal pyrolytic graphite layer is tightly combined with the aluminum alloy layer. Table 1 is a comparison between the simulation value and the measured value of the temperature field under the equivalent heat transfer coefficient and internal contact thermal resistance of the composite thermal conductive substrate in this embodiment.

[0047] Table 1 Temperature field simulation values ​​of equivalent thermal conductivity and internal contact thermal resistance in one embodiment

[0048] It should be understood that expressions such as "include" and "may include" used in this application indicate the existence of the disclosed functions, operations or constituent elements, and do not limit one or more additional functions, operations and constituent elements. In this application, terms such as "include" and / or "have" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components or combinations thereof.

[0049] It should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0052] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A composite thermally conductive substrate based on pyrolytic graphite, characterized in that: The invention comprises a metal shell (1), a heat transfer cover plate (2) and a pyrolytic graphite sheet (3); a mounting groove (104) for mounting components is provided on one side of the metal shell (1); a groove (102) adapted to be embedded in the pyrolytic graphite sheet (3) is provided at the bottom of the mounting groove (104); the heat transfer cover plate (2) is fixedly connected to the opening of the groove (102); and a heat exchange surface (105) and heat dissipation fins (106) are provided on the other side of the metal shell (1).

2. A composite thermally conductive substrate based on pyrolytic graphite according to claim 1, characterized in that: A plurality of enhanced heat-conducting pillars (101) are arranged in an array in the groove (102), the enhanced heat-conducting pillars (101) are perpendicular to the bottom surface of the groove (102), and positioning holes (301) for the enhanced heat-conducting pillars (101) to pass through are provided on the pyrolytic graphite sheet (3).

3. A composite thermally conductive substrate based on pyrolytic graphite as claimed in claim 2, characterized in that: The top of the enhanced heat-conducting support (101) abuts against the bottom of the heat-conducting cover plate (2).

4. A composite thermally conductive substrate based on pyrolytic graphite according to claim 1, characterized in that: The bottom of the installation groove (104) is also provided with a step groove (103) adapted to be embedded in the heat transfer cover plate (2), and the groove (102) is located in the middle of the step groove (103).

5. The composite thermally conductive substrate based on pyrolytic graphite according to claim 1, characterized in that: A heat transfer boss (201) is provided on the side of the heat transfer cover plate (2) facing away from the groove (102), and the heat transfer boss (201) is fitted with the heat-generating component in the installation groove (104).

6. A composite thermally conductive substrate based on pyrolytic graphite according to claim 1, characterized in that: The surface of the pyrolytic graphite sheet (3) is provided with a surface metallized protective layer.

7. A composite thermally conductive substrate based on pyrolytic graphite as claimed in claim 2, characterized in that: The enhanced heat-conducting support pillar (101) is made of heat-conducting material.

8. A composite thermally conductive substrate based on pyrolytic graphite according to any one of claims 1 to 7, characterized in that: The metal shell (1) and the heat transfer cover plate (2) are both made of aluminum alloy material.

9. A method for manufacturing a composite thermally conductive substrate, used for manufacturing a composite thermally conductive substrate based on pyrolytic graphite as claimed in any one of claims 1 to 8, characterized in that: The steps include: S1, sequentially installing a pyrolytic graphite sheet (3) and a heat transfer cover plate (2) in a metal housing (1); S2, performing a vacuum treatment on the groove (102); S3, welding the heat transfer cover plate (2) and the metal shell (1) using a vacuum pressure diffusion welding process; S4, performing vacuum treatment on the groove (102) again; S5. The groove (102) is sealed to form a closed cavity inside, thereby completing the production of the composite heat-conducting substrate.

10. The method for manufacturing a composite thermally conductive substrate according to claim 9, characterized in that: In the step S2, the metal shell (1) is provided with an exhaust port which is in communication with the groove (102) and is used to perform a vacuum treatment on the groove (102).

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