In-plane high thermal conductive graphite metal plate for blackbody uniform temperature

Abstract

The application provides an in-plane high-thermal-conductivity graphite metal plate for blackbody temperature equalization, and belongs to the field of large dynamic temperature range, high-efficiency in-plane thermal conduction and super-uniform temperature field control, and comprises a metal cover plate, a metal frame, graphite sheets and heat insulation fillers, a plurality of graphite sheet stacks are arranged between the metal cover plate and the metal frame, the graphite sheets are filled with the heat insulation fillers, the gaps between the graphite sheets and the metal cover plate and the metal frame are filled with the heat insulation fillers, and the metal cover plate and the metal frame are welded and fixed. The application has the characteristics of in-plane high thermal conductivity and longitudinal low thermal conductivity, can improve the in-plane temperature equalization of the blackbody and simultaneously intercept the transmission of the in-plane temperature difference in the longitudinal direction, and has the advantages of excellent temperature equalization, light weight, good mechanical properties and the like.

Description

Technical Field

[0001] This invention belongs to the field of large dynamic temperature range, in-plane high-efficiency thermal conductivity, and ultra-uniform temperature field control, and specifically relates to an in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity. Background Technology

[0002] Infrared remote sensing technology is widely used in space remote sensing, especially in climate change observation and numerical weather prediction, where the quantitative requirements for infrared remote sensing data are increasingly stringent. This necessitates blackbodies with large apertures, wide dynamic temperature ranges, high temperature stability, and high temperature uniformity. To meet the current requirements for high on-orbit temperature uniformity of spaceborne blackbodies in remote sensing payloads (the in-plane uniformity requirement for blackbodies is generally ≤0.1K, or even higher), the design of a temperature homogenizing structure with high in-plane thermal conductivity, low longitudinal thermal conductivity, high stability, and a wide dynamic temperature range is urgently needed.

[0003] Currently, widely used blackbody heat pipes and pure metal plates are the main heat pipe cooling methods. Heat pipes have extremely high thermal conductivity and require no additional energy, with an equivalent thermal conductivity of 5000-20000 W / m·K. However, their operating temperature range is relatively narrow, and ground-based applications require maintaining a gravity-fed orientation. Once the specific operating range is exceeded, heat pipes are prone to failure or performance instability, which is a serious constraint for blackbody heat pipes, which have extremely high requirements for temperature uniformity and stability. Traditional pure metal plates, due to their low thermal conductivity and heavy weight, also struggle to meet increasingly stringent heat pipe cooling requirements. Currently, conventional graphite heat pipes are widely used in electronic heat dissipation. To improve their heat dissipation effect, graphite and metal plates are generally nickel-plated and then soldered, or welded using high thermal conductivity fillers. The resulting graphite heat pipes have high longitudinal thermal conductivity. Furthermore, to further improve their longitudinal thermal conductivity, the heat pipes typically have several uniformly arranged heat-conducting columns. However, the heat exchange plate made using the above process has a high longitudinal thermal conductivity, which cannot effectively intercept the longitudinal transfer of temperature difference during the surface-to-surface heat transfer process. Therefore, it is not suitable for direct use in the field of blackbody heat exchange. Summary of the Invention

[0004] To address the limitations of heat pipe operating environments, the poor temperature uniformity of pure metal plates, and the unsuitability of conventional graphite vapor chambers, this invention provides a graphite metal plate with high in-plane thermal conductivity for blackbody temperature uniformity. A graphite metal plate with high in-plane thermal conductivity refers to a graphite metal plate with a high thermal conductivity along its two-dimensional plane, significantly higher than its thermal conductivity along its thickness. This invention uses metal encapsulation of a graphite sheet laminate formed by combining graphite sheets and insulating fillers, giving the metal plate excellent in-plane thermal conductivity and longitudinal insulation capabilities, improving blackbody temperature uniformity while enhancing structural strength. The graphite metal plate's high in-plane thermal conductivity effectively facilitates heat transfer within the plane and reduces in-plane temperature gradients; its low thermal conductivity along its thickness effectively intercepts the longitudinal transmission of in-plane temperature differences. Based on the in-plane and longitudinal thermal conductivity characteristics of the graphite sheets and the insulation properties of the insulating fillers, graphite vapor chambers with different in-plane and longitudinal thermal conductivity requirements can be designed to meet blackbody temperature uniformity requirements.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A high thermal conductivity in-plane graphite metal plate for blackbody temperature equalization includes a metal cover plate, a metal frame, multiple graphite sheets, and thermal insulation filler. The metal frame is a groove-enclosing structure composed of a metal frame border and a metal frame base plate. The periphery of the metal frame border has adhesive drainage holes, and the surface of the metal frame base plate has perforated columns. Thermal insulation filler is filled between adjacent graphite sheets, and the gaps between the graphite sheets and the metal cover plate and metal frame are also filled with thermal insulation filler. Multiple graphite sheets and thermal insulation material are stacked and placed within the space enclosed by the metal frame border, metal frame base plate, and perforated columns. The metal cover plate and metal frame are welded and fixed. The high thermal conductivity in-plane graphite metal plate has a higher thermal conductivity along its two-dimensional plane than along its thickness.

[0007] Furthermore, the total number of layers of multilayer graphite sheets and thermal insulation material is 3-10 layers, the thickness of a single layer of graphite sheet is 0.8mm, and the thermal conductivity is ≥1500 W / (m·K).

[0008] Furthermore, the thickness of the thermal insulation filler between adjacent graphite sheets is 0.2mm~1.0mm, the thermal conductivity of the thermal insulation filler is ≤0.5 W / (m·K), the working temperature range is -200~+200℃, the thermal conductivity is poor, and the temperature tolerance range is wide.

[0009] Furthermore, the graphite sheets are processed into shapes using a die-cutting process.

[0010] Furthermore, the graphite sheet is provided with a second through hole corresponding to the perforated column.

[0011] Furthermore, the perforated columns on the surface of the metal frame base plate are evenly distributed for the installation and fixation of the graphite metal plate and the temperature uniformity target.

[0012] Furthermore, the upper surface of the metal frame border is provided with steps.

[0013] Furthermore, the upper surface of the perforated column on the surface of the metal frame base plate is provided with a step.

[0014] Furthermore, the periphery of the metal frame edge is provided with glue discharge holes with a diameter of 1.0 to 2.0 mm at intervals of 30 to 50 mm.

[0015] Furthermore, the metal cover plate is provided with a first through hole corresponding to the step size of the post; the side of the metal cover plate contacts the step of the metal frame frame.

[0016] Furthermore, friction stir welding, nitrogen shielded welding, or vacuum diffusion welding are used to form and weld the first through hole and side of the metal cover plate to the metal frame frame and hole post.

[0017] Beneficial effects:

[0018] 1. The graphite metal plate of the present invention is a graphite sheet laminate formed by splicing graphite sheets and heat insulation fillers layer by layer. It has high in-plane thermal conductivity and longitudinal heat insulation capability, which can effectively intercept the transmission of in-plane temperature difference in the longitudinal direction. Compared with conventional graphite heat spreaders, it has a better temperature uniformity effect.

[0019] 2. Graphite metal plates have the characteristics of wide operating temperature range, easy processing, light weight, and stable and reliable performance, which can meet the application requirements of blackbody for high temperature uniformity, high stability, and coverage of a large dynamic operating temperature range.

[0020] In summary, compared to heat pipe temperature equalization, blackbody operates over a wider temperature range, avoiding the impact of heat pipe failure outside the operating temperature range, failure to start due to gravity, and performance instability on the temperature uniformity of the blackbody. It remains stable and reliable under temperature shocks and overload acceleration, and significantly reduces development costs and shortens the development cycle. Compared to pure metal plates and conventional graphite temperature equalization plates, this invention simultaneously possesses higher in-plane thermal conductivity and lower longitudinal thermal conductivity, improving the in-plane temperature uniformity of the blackbody and intercepting the longitudinal transmission of in-plane temperature differences. It offers advantages such as excellent temperature uniformity and light weight. Furthermore, graphite metal plates are unaffected by ambient temperature and gravity, remaining stable and reliable under temperature shocks and overload acceleration. Compared to heat pipes, it reduces development costs, significantly shortens the development cycle, and provides significantly better temperature equalization performance than pure metal plates and conventional graphite temperature equalization plates. Attached Figure Description

[0021] Figure 1 This is a cross-sectional perspective view of an in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity according to the present invention.

[0022] Figure 2 This is a schematic diagram of the metal frame structure of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of the metal cover plate of the present invention;

[0024] Figure 4 This is a schematic diagram of the structure of the multilayer graphite sheets stacked according to the present invention;

[0025] The attached figures are labeled as follows: metal cover plate 1, metal frame 2, graphite sheet 3, heat insulation filler 4, first through hole 12, side 13, metal frame frame 21, metal frame base plate 22, glue drain hole 23, hole column 24, and second through hole 31. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0027] like Figures 1-4 As shown, an embodiment of the present invention provides an in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity, comprising a metal cover plate 1, a metal frame 2, graphite sheets 3, and thermal insulation filler 4. Multiple layers of graphite sheets 3 are stacked between the metal cover plate 1 and the metal frame 2. Thermal insulation filler 4 is filled between the graphite sheets 3 and in the gaps between the graphite sheets 3 and the metal cover plate 1 and the metal frame 2. The metal cover plate 1 and the metal frame 2 are welded and fixed together.

[0028] Preferred, such as Figure 2 As shown, the metal frame 2 is a groove-enclosing structure composed of a metal frame side plate 21 and a metal frame base plate 22. A glue-draining hole 23 is provided around the metal frame side plate 21. The surface of the metal frame base plate 22 and the interior of the groove structure are provided with perforated columns 24. Multilayer graphite sheets 3 are placed in the space enclosed by the metal frame side plate 21, the metal frame base plate 22, and the perforated columns 24.

[0029] Preferably, it is generally composed of 3 to 10 layers of graphite sheets 3 and heat insulation filler 4 spliced ​​together layer by layer, wherein the thickness of a single layer of graphite sheet 3 is 0.8 mm and the thermal conductivity is ≥1500 W / (m·K).

[0030] Preferably, the thickness of the heat insulation filler 4 filling between the graphite sheets 3 is generally 0.2mm~1.0mm, the thermal conductivity of the heat insulation filler 4 is ≤0.5 W / (m·K), and the working temperature range is -200~+200℃.

[0031] Preferably, the graphite sheet 3 is formed using a die-cutting process, with a dimensional accuracy better than 0.1mm.

[0032] Preferably, the perforated posts 24 on the metal frame 2 should be evenly distributed for mounting and fixing the graphite metal plate and the blackbody.

[0033] Preferably, the upper surface of the metal frame edge 21 has steps for limiting positioning during encapsulation and bearing load during welding.

[0034] Preferably, the upper surface of the perforated post 24 on the metal frame 2 has a step.

[0035] Preferably, the metal frame edge 21 is provided with glue discharge holes 23 with a diameter of 1.0 to 2.0 mm at intervals of 30 to 50 mm, for discharging excess heat insulation filler.

[0036] Preferably, discharge holes 23 are provided at 40 mm intervals, and their diameter is 1.5 mm.

[0037] Preferred, such as Figure 3 As shown, the metal cover plate 1 is provided with a first through hole 12 corresponding to the step size of the post 24, which is used for limiting during sealing; the side 13 of the metal cover plate 1 contacts the step of the metal frame frame 21.

[0038] Preferably, the dimensions of the surrounding groove structure are 220mm × 220mm × 9mm.

[0039] Preferably, the step thickness on the upper surface of the metal frame edge 21 is 0.3 mm, and the total thickness of the sidewalls is 0.5 mm. The wall thickness is as thin as possible to reduce weight and decrease longitudinal heat transfer.

[0040] Preferably, the step thickness on the upper surface of the perforated column 24 on the surface of the metal frame base plate 22 is 0.3 mm, and the hole thickness is 0.5 mm. The wall thickness is as thin as possible to reduce weight and longitudinal heat transfer.

[0041] like Figure 4 As shown, the stack of multilayer graphite sheets 3 is composed of 5 layers of graphite sheets 3 and heat insulation filler 4 spliced ​​together layer by layer. The thickness of a single layer of graphite sheet 3 is 0.8 mm, the thickness of a single layer of heat insulation filler 4 is 0.3 mm, and the thermal conductivity is ≥1500 W / m·K.

[0042] The graphite sheet 3 is provided with a second through hole 31 corresponding to the size of the post 24. The outer contour of the second through hole 31 of the graphite sheet 3 is formed by die cutting, and the dimensional accuracy is better than 0.1mm.

[0043] The first through hole 12 and side 13 of the metal cover plate 1 are formed and welded to the metal frame frame 21 and hole column 24 of the metal frame 2 using processes such as friction stir welding, nitrogen shielded welding or vacuum diffusion welding.

[0044] To demonstrate the beneficial effects of this invention, the following specific embodiments were compared:

[0045] Example:

[0046] This invention involves fabricating a graphite metal plate with dimensions of 220mm × 220mm × 9mm. Five layers of graphite sheets are stacked together, and the graphite sheets and thermal insulation filler are placed within a surrounding groove structure of a metal cover plate and a metal frame. The thickness of the metal cover plate and metal frame at their planar positions is 1.6mm. The metal cover plate 1 and metal frame 2 are then welded together using friction stir welding. Finally, the metal surface undergoes surface treatment. The total weight of the processed graphite metal is 1085g, with an in-plane thermal conductivity of 950W / m·K and a longitudinal thermal conductivity of 1.6W / m·K.

[0047] Comparative Example 1:

[0048] Fabricate an aluminum alloy (grade 2A12) metal plate with dimensions of 220mm × 220mm × 9mm. The total weight is 1296g, the in-plane thermal conductivity is 121W / m·K, and the longitudinal thermal conductivity is 121W / m·K.

[0049] Comparative Example 2:

[0050] Make a copper (grade T3) metal plate with dimensions of 220mm × 220mm × 9mm. It should weigh 4079g, have an in-plane thermal conductivity of 380W / m·K, and a longitudinal thermal conductivity of 380W / m·K.

[0051] Comparative Example 3:

[0052] Fabricate a standard graphite heat spreader with dimensions of 220mm × 220mm × 9mm. It weighs 1115g, has an in-plane thermal conductivity of 950W / m·K, and a longitudinal thermal conductivity of 300W / m·K.

[0053] The uniformity and temperature level of the blackbody were tested under vacuum and a 100 K cold background environment. The tested uniform temperature distribution structures were: a 9 mm thick aluminum alloy plate, a 9 mm thick copper plate, a 9 mm thick conventional graphite uniform temperature distribution plate, and a 9 mm thick graphite metal plate. A multi-channel thermometer was used for testing, with a temperature resolution of 0.01 K. Test conditions: One side of each of the above uniform temperature distribution structures had a heating element and two heat pipes evenly attached; the heating element applied a power of 60 W, and the heat pipes were used for cooling the blackbody; the other side of the uniform temperature distribution structure (i.e., the aluminum alloy metal plate, the copper metal plate, the conventional uniform temperature distribution plate, and the graphite metal plate of this invention) was thermally connected to the blackbody; seven platinum resistance thermometers were evenly arranged at the bottom of the blackbody.

[0054] The test results of the above embodiments are shown in Table 1 below: The test results show that the 9mm thick graphite metal plate has the best temperature uniformity performance for the blackbody, with a temperature difference reduction of 0.42℃ compared with aluminum alloy metal plate, a temperature difference reduction of 0.18℃ compared with copper metal plate, and a temperature difference reduction of 0.07℃ compared with conventional graphite temperature uniform plate.

[0055] Table 1. Blackbody temperature uniformity and temperature level

[0056]

[0057] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention does not limit the above embodiments. For those skilled in the art, after learning the contents of the present invention, they can make several equivalent changes and substitutions without departing from the principle of the present invention. These equivalent changes and substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. A high thermal conductivity in-plane graphite metal plate for blackbody temperature uniformization, characterized in that, This component is used for heat equalization of a spaceborne blackbody in remote sensing payloads. It includes a metal cover plate, a metal frame, multiple layers of graphite sheets, and thermal insulation filler. The metal frame is a groove-enclosing structure composed of a metal frame border and a metal frame base plate. The perimeter of the metal frame border has adhesive drainage holes, and the surface of the metal frame base plate has perforated columns. Thermal insulation filler is used to fill the gaps between adjacent graphite sheets and between the graphite sheets and the metal cover plate and metal frame. Multiple layers of graphite sheets and thermal insulation material are stacked and placed within the space enclosed by the metal frame border, metal frame base plate, and perforated columns. The metal cover plate and metal frame are welded and fixed. The in-plane high thermal conductivity graphite metal sheet has a higher thermal conductivity along its two-dimensional plane than along its thickness. The thickness of a single layer of graphite sheet is 0.8 mm, and the thickness of the thermal insulation filler between adjacent graphite sheets is 0.2 mm to 1.0 mm, with a thermal conductivity ≥1500 W / (m·K) and an operating temperature range of -200 to +200℃.

2. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity according to claim 1, characterized in that, The total number of layers of multi-layer graphite sheets and thermal insulation materials is 3-10.

3. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity as described in claim 2, characterized in that, The thermal conductivity of the insulating filler is ≤0.5 W / (m·K).

4. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformization according to claim 2, characterized in that, Graphite sheets are shaped using a die-cutting process.

5. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformization according to claim 1, characterized in that, The graphite sheet is provided with a second through hole corresponding to the post.

6. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformization according to claim 1, characterized in that, The perforated columns on the surface of the metal frame base plate are evenly distributed for the installation and fixation of the graphite metal plate and the temperature uniformity target.

7. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformization according to claim 1, characterized in that, The upper surface of the metal frame border has steps.

8. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformization according to claim 1, characterized in that, The upper surface of the perforated column on the surface of the metal frame base plate is provided with a step.

9. A high thermal conductivity in-plane graphite metal plate for blackbody temperature uniformity as described in claim 1, characterized in that, The metal frame edge is provided with glue drainage holes of 1.0 to 2.0 mm in diameter at intervals of 30 to 50 mm.

10. A high thermal conductivity in-plane graphite metal plate for blackbody temperature uniformization according to claim 1, characterized in that, The metal cover plate is provided with a first through hole corresponding to the step size of the post; the side of the metal cover plate contacts the step of the metal frame frame.

11. A high thermal conductivity in-plane graphite metal plate for blackbody temperature uniformization according to claim 1, characterized in that, The first through hole and side of the metal cover plate are formed and welded to the metal frame frame and hole column by friction stir welding, nitrogen shielded welding or vacuum diffusion welding.

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