In-plane high-thermal-conductivity graphite metal plate for blackbody temperature equalization

Abstract

The invention provides an in-plane high-thermal-conductivity graphite metal plate for blackbody temperature equalization, and belongs to the field of large dynamic temperature zone, efficient in-plane thermal conductivity and super-uniform temperature field control, the in-plane high-thermal-conductivity graphite metal plate comprises a metal cover plate, a metal frame, graphite flakes and a heat insulation filler, and the multiple layers of graphite flakes are stacked between the metal cover plate and the metal frame; gaps between the graphite flakes and the metal cover plate as well as between the graphite flakes and the metal frame are filled with heat-insulating fillers; the metal cover plate and the metal frame are welded and fixed. The black body has the characteristics of high in-plane thermal conductivity and low longitudinal thermal conductivity, can improve in-plane temperature uniformity of the black body and intercept longitudinal transmission of in-plane temperature difference, and has the advantages of excellent temperature uniformity, light weight, good mechanical property and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of large dynamic temperature range, high in-plane thermal conductivity, and ultra-uniform temperature field control, and particularly relates to a high in-plane thermal conductivity graphite metal plate for blackbody temperature uniformity. BACKGROUND

[0002] Infrared remote sensing technology is widely used in space remote sensing detection fields, and especially in the fields of climate change observation and numerical weather prediction, the quantitative level of infrared remote sensing data is required to be higher and higher, and a blackbody with a large aperture, a large dynamic temperature range, high temperature stability, and high temperature uniformity is needed. In order to meet the on-orbit high temperature uniformity requirement of the current remote sensing load satellite blackbody (the general uniformity requirement of the blackbody surface is ≤0.1K, or even higher), it is urgent to design a temperature uniformity structure with high in-plane thermal conductivity, low longitudinal thermal conductivity, high stability, and large dynamic temperature range.

[0003] The currently widely used blackbody temperature uniformity measures mainly include heat pipes and pure metal plates. The heat pipe has extremely high thermal conductivity and does not require additional energy, and the equivalent thermal conductivity is as high as 5000-20000W / m·K, but its working temperature range is relatively narrow, and the ground use needs to ensure the gravity attitude. Once it exceeds the specific working range, the heat pipe is prone to failure or unstable performance, which is a serious constraint factor for blackbodies with extremely high temperature uniformity and temperature stability. The traditional pure metal plate is also difficult to meet the increasingly stringent temperature uniformity requirements due to its low thermal conductivity and heavy weight. The current conventional graphite temperature uniformity plate has been widely used in the field of electronic heat dissipation. In order to improve its heat dissipation effect, the graphite and metal plate are generally plated with nickel and then soldered or welded with high thermal conductivity filler. The produced graphite temperature uniformity plate has high longitudinal thermal conductivity. In order to further improve the longitudinal thermal conductivity, the temperature uniformity plate is generally uniformly arranged with several heat conducting columns. However, the temperature uniformity plate produced by the above process has high longitudinal thermal conductivity, and cannot effectively intercept the temperature difference in the longitudinal transmission of heat during the face-to-face transmission process, so it is not suitable for direct use in the field of blackbody temperature uniformity. SUMMARY

[0004] To solve the problems of limited working environment of heat pipe, poor uniformity of pure metal plate, and inapplicability of conventional graphite uniformity plate, the application provides an in-plane high-thermal-conductivity graphite metal plate for blackbody temperature uniformity. The in-plane high-thermal-conductivity graphite metal plate refers to that the graphite metal plate has high thermal conductivity in the two-dimensional plane direction, which is significantly higher than the thermal conductivity in the thickness direction. The application encapsulates the graphite sheet layer stack formed by the combination of graphite sheet and heat insulation filler with metal, so that the metal plate has good in-plane thermal conductivity and longitudinal heat insulation capacity, which can improve the blackbody temperature uniformity and enhance the structural strength. The graphite metal plate has high in-plane thermal conductivity, which can effectively conduct heat in the plane and reduce the temperature gradient in the plane. The graphite metal plate has low thermal conductivity in the thickness direction, which can effectively intercept the transmission of the temperature difference in the plane in the longitudinal direction. According to the in-plane and longitudinal thermal conductivity characteristics of the graphite sheet and the heat insulation characteristics of the heat insulation filler, the graphite uniformity plate with different in-plane thermal conductivity and different longitudinal thermal conductivity requirements can be designed to meet the blackbody temperature uniformity requirements.

[0005] To achieve the above-mentioned purposes, the application adopts the following technical solutions:

[0006] The in-plane high-thermal-conductivity graphite metal plate for blackbody temperature uniformity comprises a metal cover plate, a metal frame, a plurality of graphite sheets, and heat insulation filler. The metal frame is a surrounding groove structure composed of a metal frame edge frame and a metal frame bottom plate. The metal frame edge frame is provided with glue discharge holes around the periphery, and the surface of the metal frame bottom plate is provided with hole columns. The heat insulation filler is filled between adjacent graphite sheets, and the heat insulation filler is filled in the gaps between the graphite sheets and the metal cover plate and the metal frame. The plurality of graphite sheets and the heat insulation material are stacked in the space surrounded by the metal frame edge frame, the metal frame bottom plate, and the hole columns. The metal cover plate and the metal frame are welded and fixed. The in-plane high-thermal-conductivity graphite metal plate has higher thermal conductivity in the two-dimensional plane direction than in the thickness direction.

[0007] Further, the total number of layers of the plurality of graphite sheets and the heat insulation material is 3-10 layers, the single-layer thickness of the graphite sheet is 0.8 mm, and the thermal conductivity is greater than or equal to 1500 W / (m·K).

[0008] Further, the thickness of the heat insulation filler filled between adjacent graphite sheets is 0.2 mm-1.0 mm, the thermal conductivity of the heat insulation filler is less than or equal to 0.5 W / (m·K), the working temperature range is-200-+200℃, the thermal conductivity is poor, and the temperature resistance range is wide.

[0009] Further, the graphite sheet is processed and formed by die cutting process.

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

[0011] Further, the hole columns on the surface of the metal frame bottom plate are uniformly distributed and used for the installation and fixation of the graphite metal plate and the temperature uniformity target.

[0012] Further, the upper surface of the metal frame is provided with a step.

[0013] Further, the upper surface of the metal frame is provided with a step.

[0014] Further, the metal frame is provided with a step.

[0015] Further, the metal frame is provided with a step.

[0016] Further, the metal frame is provided with a step.

[0017] Beneficial effects:

[0018] 1. The graphite metal plate of the present application adopts a graphite sheet, a heat insulation filler, and a graphite sheet laminated body formed by layer-by-layer splicing, has high in-plane thermal conductivity and longitudinal heat insulation capacity, can effectively intercept the transmission of in-plane temperature difference in the longitudinal direction, and has better temperature uniformity than conventional graphite heat uniform plates.

[0019] 2. The graphite metal plate has a wide working temperature range, is easy to process, has stable and reliable performance, and the like, and can meet the application requirements of high temperature uniformity, high stability, and covering a large dynamic working temperature range.

[0020] In summary, compared with the heat pipe temperature uniform method, the blackbody working temperature range is wider, which can avoid the influence of heat pipe failure, ground reverse gravity non-starting, and unstable performance on the temperature uniformity of the blackbody, and is still stable and reliable under temperature impact and overload acceleration, and greatly reduces the development cost and shortens the development cycle; compared with the pure metal plate and the conventional graphite heat uniform plate, the present application has higher in-plane thermal conductivity and lower longitudinal thermal conductivity, which can improve the in-plane temperature uniformity of the blackbody and intercept the transmission of in-plane temperature difference in the longitudinal direction, has excellent temperature uniformity, light weight, and the like. At the same time, the graphite metal plate is not affected by the working environment temperature, gravity, and the like, and is still stable and reliable under temperature impact and overload acceleration, compared with the heat pipe, the development cost is reduced, the development cycle is significantly shortened, and the temperature uniformity is obviously better than the pure metal plate and the conventional graphite heat uniform plate. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a sectional view of the in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity of the present application;

[0022] Figure 2 is a structural schematic diagram of the metal frame of the present application;

[0023] Figure 3 Structure diagram of the metal cover plate of the present application;

[0024] Figure 4 Structure diagram of the multi-layer graphite sheet stack of the present application;

[0025] Wherein, the reference signs are: metal cover plate 1, metal frame 2, graphite sheet 3, thermal insulation filler 4, first through hole 12, side edge 13, metal frame edge frame 21, metal frame bottom plate 22, glue discharge hole 23, hole column 24, second through hole 31. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0027] As shown in Figures 1-4 , a high in-plane thermal conductivity graphite metal plate for blackbody uniform temperature of an embodiment of the present application includes a metal cover plate 1, a metal frame 2, a graphite sheet 3, and a thermal insulation filler 4. The multi-layer graphite sheet 3 is stacked between the metal cover plate 1 and the metal frame 2. The graphite sheet 3 and the graphite sheet 3 are filled with the thermal insulation filler 4, and the gap between the graphite sheet 3 and the metal cover plate 1 and the metal frame 2 is filled with the thermal insulation filler 4; the metal cover plate 1 and the metal frame 2 are welded and fixed.

[0028] Preferably, as shown in Figure 2 , the metal frame 2 is a surrounding groove structure composed of a metal frame edge frame 21 and a metal frame bottom plate 22, and the metal frame edge frame 21 is provided with glue discharge holes 23 around the periphery; the surface of the metal frame bottom plate 22 and the inside of the groove structure are provided with hole columns 24; the multi-layer graphite sheet 3 is placed in the space surrounded by the metal frame edge frame 21, the metal frame bottom plate 22 and the hole columns 24.

[0029] Preferably, it is generally composed of 3-10 layers of graphite sheets 3 and thermal insulation fillers 4 spliced layer by layer, the single-layer thickness of the graphite sheet 3 is 0.8mm, and the thermal conductivity coefficient is ≥1500 W / (m·K).

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

[0031] Preferably, the graphite sheet 3 is processed by die cutting process, and the dimensional accuracy is better than 0.1mm.

[0032] Preferably, the holes 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 frame 21 has steps for limiting the position during packaging and bearing the force during welding.

[0034] Preferably, the upper surface of the hole column 24 on the metal frame 2 has steps.

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

[0036] Preferably, the glue discharge holes 23 are arranged at intervals of 40 mm and have a diameter of 1.5 mm.

[0037] Preferably, Figure 3 As shown, the metal cover plate 1 is provided with a first through hole 12 corresponding to the step size of the hole column 24 for limiting the position during packaging; the side 13 of the metal cover plate 1 contacts the step of the metal frame border 21.

[0038] Preferably, the size of the surrounding groove structure is 220 mm×220 mm×9 mm.

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

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

[0041] like Figure 4 As shown, the stack of multi-layer graphite sheets 3 is formed by splicing 5 layers of graphite sheets 3 and thermal insulation fillers 4 layer by layer. The thickness of a single layer of the graphite sheet 3 is 0.8 mm, the thickness of a single layer of the thermal 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 having a size corresponding to the hole column 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 0.1 mm.

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

[0044] In order to demonstrate the beneficial effects of this invention, the following specific examples are compared:

[0045] Embodiment:

[0046] A graphite metal plate with a size of 220 mm x 220 mm x 9 mm is made. The graphite sheet has 5 layers, and the graphite sheet and the heat insulation filler are stacked in the surrounding groove structure of the metal cover plate and the metal frame. The thickness of the metal cover plate and the metal frame is 1.6 mm. Then, the metal cover plate 1 and the metal frame 2 are welded by friction stir welding. Finally, the metal surface is processed in a plane. The total weight of the processed graphite metal is 1085 g, the in-plane thermal conductivity is 950 W / m·K, and the longitudinal thermal conductivity is 1.6 W / m·K.

[0047] Comparative Example 1:

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

[0049] Comparative Example 2:

[0050] A red copper (grade T3) metal plate with a size of 220 mm x 220 mm x 9 mm is made. The weight is 4079 g, the in-plane thermal conductivity is 380 W / m·K, and the longitudinal thermal conductivity is 380 W / m·K.

[0051] Comparative Example 3:

[0052] A conventional graphite heat sink plate with a size of 220 mm x 220 mm x 9 mm is made. The weight is 1115 g, the in-plane thermal conductivity is 950 W / m·K, and the longitudinal thermal conductivity is 300 W / m·K.

[0053] The following tests the uniformity and temperature level of the blackbody in a vacuum and 100 K cold background environment. The tested uniform structure products are as follows: 9 mm thick aluminum alloy plate, 9 mm thick red copper plate, 9 mm thick conventional graphite heat sink plate, and 9 mm thick graphite metal plate. A multi-channel temperature meter is used for testing with a temperature resolution of 0.01 K. The test state is that one side of the above uniform structure is uniformly pasted with a heating sheet and two heat pipes; the heating sheet applies a power of 60 W, and the heat pipes are used for blackbody cooling; the other side of the uniform structure (i.e., the aluminum alloy metal plate, the red copper metal plate, the conventional graphite heat sink plate, and the graphite metal plate of the present application) is in thermal contact with the blackbody; and the bottom of the blackbody is uniformly arranged with seven platinum resistors.

[0054] The test results of the above examples are shown in Table 1. The test results show that the 9 mm thick graphite metal plate has the best temperature uniformity for the blackbody, with a temperature difference reduction of 0.42°C compared to the aluminum alloy metal plate, 0.18°C compared to the red copper metal plate, and 0.07°C compared to the conventional graphite heat sink plate.

[0055] Table 1 Blackbody temperature uniformity and temperature levels

[0056]

[0057] The above detailed description of the preferred embodiments of the present application is only for the purpose of illustrating the principles of the present application, and not for limiting the scope of the present application. It is obvious to those skilled in the art that, based on the disclosure of the present application, various equivalent modifications and substitutions can be made without departing from the principles of the present application, and these equivalent modifications and substitutions should also be considered as falling within the scope of the present application.

Claims

1. A high thermal conductivity graphite metal plate for blackbody temperature uniformity, characterized in that: The device is used for temperature equalization of a satellite-borne blackbody for remote sensing payloads and includes a metal cover, a metal frame, multi-layer graphite sheets, and thermal insulation fillers. The metal frame is an enclosed groove structure consisting of a metal frame frame and a metal frame base plate. The metal frame frame is provided with glue drainage holes around its perimeter, and the metal frame base plate is provided with perforated columns. The thermal insulation fillers are filled between adjacent graphite sheets, and the gaps between the graphite sheets, the metal cover, and the metal frame are filled with the thermal insulation fillers. The multi-layer graphite sheets and thermal insulation material are stacked and placed in the space enclosed by the metal frame frame, the metal frame base plate, and the perforated columns. The metal cover and the metal frame are welded and secured. 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 fillers between adjacent graphite sheets is 0.2 mm to 1.0 mm. The thermal conductivity is ≥1500 W / (m·K), and the operating temperature range is -200°C to +200°C.

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 the multi-layer graphite sheet and the thermal insulation material is 3-10 layers.

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

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

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

6. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity according to claim 1, characterized in that: The holes on the surface of the metal frame bottom plate are evenly distributed and are used for mounting and fixing the graphite metal plate and the temperature-averaging target.

7. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity according to claim 1, characterized in that: The upper surface of the metal frame edge is provided with steps.

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

9. The in-plane high thermal conductivity graphite metal plate for blackbody temperature uniformity according to claim 1, characterized in that: Glue drainage holes with a diameter of 1.0-2.0 mm are arranged at intervals of 30-50 mm around the periphery of the metal frame.

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

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

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