A metal-graphite connection structure
By employing a sandwich-structured composite layer and ultrasonic brazing between the graphite film and the metal connection end, the problem of high thermal resistance in the connection between graphite material and metal end was solved, achieving efficient, flexible and stable heat transfer.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 东莞市格瑞飞导热材料有限公司
- Filing Date
- 2025-07-01
- Publication Date
- 2026-07-03
Smart Images
Figure CN224460330U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of metal-graphite joining technology, and in particular to a metal-graphite joining structure. Background Technology
[0002] With the continuous increase in the power density of electronic devices and the growing demand for lightweight thermal management systems in the aerospace field, flexible thermal conductive materials are being used more and more widely in the field of thermal control. Traditional flexible thermal conductive cables typically use metal braided tape or graphite materials as the thermal conductive medium.
[0003] A search revealed a brazing structure for a lightweight flexible graphite heat-conducting cable (authorization announcement number: CN211939411U), which "includes a graphite film laminate composed of multiple layers of graphite films, and heat-conducting metal connection ends located on both sides of the graphite film laminate; the graphite film laminate has a central flexible section and end connection sections on both sides of the graphite film, with a gold-based soft solder layer between adjacent graphite film layers on both sides of the end connection section; a sandwich-structured composite solder layer is respectively provided between the end connection sections on both sides of the graphite film and the heat-conducting metal connection ends, the sandwich-structured composite solder layer being composed of a gold-based soft solder foil, a lead-based soft solder sheet, and a gold-based soft solder foil arranged sequentially. The graphite heat-conducting cable prepared using this brazing structure has low thermal resistance at the connection interface, large heat flow, high bonding strength between the flexible graphite section and the end metal, resistance to mechanical vibration and temperature alternation shock, and high service safety and reliability."
[0004] Based on the aforementioned technologies, the applicant believes that the connection between graphite materials and metal ends is usually achieved by adhesive bonding or mechanical pressing, which results in high contact thermal resistance and seriously affects heat transfer efficiency. Although the aforementioned technologies use ultrasonic welding metal edge sealing structures, which improve the connection strength, they fail to effectively solve the thermal resistance problem at the interface between multilayer graphite films and metals. In response to the above problems, we have introduced a metal-graphite connection structure. Summary of the Invention
[0005] This utility model discloses a metal-graphite connection structure, which aims to solve the problem that the connection between graphite materials and metal ends is usually achieved by adhesive bonding or mechanical pressing, resulting in high contact thermal resistance and seriously affecting heat transfer efficiency. Although the above-mentioned technologies use ultrasonic welding metal edge sealing structures, which improve the connection strength, they have not effectively solved the technical problem of thermal resistance at the interface between multilayer graphite films and metals.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A metal-graphite connection structure includes multiple graphite films forming a graphite film laminate. The graphite film laminate includes a central flexible section and end connecting sections on both sides. Thermally conductive metal connecting ends are provided on both sides of the graphite film laminate for connecting a heat source or radiator. A sandwich structure composite layer is provided between the graphite film end connecting sections and the thermally conductive metal connecting ends. The sandwich structure composite layer is formed by alternatingly stacking at least two layers of graphite foil and at least one layer of thermally conductive metal sheet. The graphite film laminate and the thermally conductive metal connecting ends are formed into an integrated connection structure by ultrasonic brazing. The contact surface between the end connecting sections of the graphite film laminate and the thermally conductive metal connecting ends is provided with a metallized layer.
[0008] The graphite film laminate, through its special structural design of a flexible middle section and end connecting sections, ensures both the overall structural flexibility and reliable connection with the heat-conducting metal connection end, thus achieving an integrated design of flexible heat conduction.
[0009] In a preferred embodiment, the graphite film is selected from pyrolytic graphite sheets, and each layer of graphite film extends along the planar direction and is stacked parallel to each other, with a single layer thickness of 10μm to 300μm.
[0010] A graphite film laminate is constructed by stacking graphite films of a specific thickness in parallel, which ensures lightweight structure and process feasibility while maintaining excellent in-plane thermal conductivity.
[0011] In a preferred embodiment, the metallization layer is a copper, nickel, or silver layer formed on the surface of the graphite film by vacuum sputtering or electroplating. The metallization layer completely covers the connecting surface of the end connecting section of the graphite film and extends 3 to 10 mm towards the middle flexible section, with a thickness of 0.3 μm to 3 μm.
[0012] The metallization layer, applied by vacuum sputtering or electroplating, covers the end joint of the graphite film, significantly improving the interfacial bonding performance between the graphite material and the metal, and providing an ideal connection basis for subsequent ultrasonic brazing.
[0013] In a preferred embodiment, the planar dimensions of the thermally conductive metal sheet match those of the graphite foil, the edges of the metal sheet are spaced 0.1 to 1 mm apart from the edges of the graphite foil, and the thickness is 10 μm to 200 μm.
[0014] The edge spacing design between the thermally conductive metal sheet and the graphite foil ensures effective heat dissipation while avoiding interlayer stress concentration, thus maintaining the stability of the connection structure during long-term use.
[0015] In a preferred embodiment, the ratio of graphite foil to thermally conductive metal sheet in the sandwich structure composite layer is 2:1 to 5:1, and the layers are connected by solid-phase diffusion through frictional heat generated by ultrasonic vibration. The total thickness of the composite layer is 100μm to 1000μm.
[0016] The sandwich structure composite layer uses graphite foil and thermally conductive metal sheets stacked alternately in a specific ratio, which optimizes the heat conduction path and ensures the mechanical strength of the structure, achieving a balance between thermal performance and reliability.
[0017] In a preferred embodiment, the overlapping area of the graphite film and the heat-conducting metal connection end is provided with a regularly arranged array of heat transfer holes. The heat transfer holes penetrate the graphite film laminate and the metallization layer, with a hole diameter of 0.1 mm to 2 mm and a hole spacing of 1.5 to 3 times the hole diameter.
[0018] The arrangement of the heat transfer hole array significantly improves the heat conduction efficiency in the vertical direction. Its regular arrangement increases the heat dissipation area and avoids the reduction in structural strength caused by the openings.
[0019] The metal-graphite connection structure provided by this utility model has the following advantages:
[0020] Firstly, the graphite film laminate is connected to the thermally conductive metal interface through a sandwich-structured composite layer. The metallization layer enhances the interfacial bonding, and the heat transfer hole array optimizes vertical heat conduction. The flexible middle section ensures structural flexibility, and ultrasonic brazing achieves metallurgical bonding, significantly reducing contact thermal resistance. This structure combines high thermal conductivity, excellent flexibility, and wide temperature range stability.
[0021] Secondly, the edge spacing design between the thermally conductive metal sheet and the graphite foil ensures effective heat dissipation while avoiding stress concentration between layers, thus maintaining the stability of the connection structure during long-term use. The sandwich structure composite layer uses a specific ratio of alternating graphite foil and thermally conductive metal sheets, which optimizes the heat conduction path while ensuring the mechanical strength of the structure, achieving a balance between thermal performance and reliability. The arrangement of the heat transfer hole array significantly improves the vertical heat conduction efficiency, and its regular arrangement increases the heat dissipation area while avoiding a decrease in structural strength caused by the openings. Attached Figure Description
[0022] Figure 1 This is a schematic cross-sectional view of a metal-graphite connection structure proposed in this utility model.
[0023] Figure 2 This is a cross-sectional schematic diagram of a metal-graphite connection structure proposed in this utility model.
[0024] Figure 3 This is a cross-sectional schematic diagram of a metal-graphite connection structure proposed in this utility model.
[0025] In the attached figures: 1. Graphite film laminate; 2. Intermediate flexible section; 3. End connection section; 4. Thermally conductive metal connection end; 5. Sandwich structure composite layer; 6. Graphite foil; 7. Thermally conductive metal sheet; 8. Metallized layer; 9. Graphite film; 10. Heat transfer hole array. Detailed Implementation
[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and marked in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0027] The metal-graphite connection structure disclosed in this utility model is mainly used in scenarios involving metal-graphite connections.
[0028] Reference Figures 1-3 A metal-graphite connection structure includes multiple graphite films 9, which together form a graphite film laminate 1. The graphite film laminate 1 includes a central flexible segment 2 and end connecting segments 3 on both sides. Thermally conductive metal connecting ends 4 are provided on both sides of the graphite film laminate for connecting heat sources or heat sinks. A sandwich structure composite layer 5 is provided between the graphite film end connecting segments 3 and the thermally conductive metal connecting ends 4. The sandwich structure composite layer 5 is formed by alternatingly stacking at least two layers of graphite foil 6 and at least one layer of thermally conductive metal sheet 7. The graphite film laminate 1 and the thermally conductive metal connecting ends 4 are integrated into a single connection structure by ultrasonic brazing. A metallized layer 8 is provided at the contact surface between the end connecting segments 3 and the thermally conductive metal connecting ends 4. The graphite films 9 are selected from pyrolytic graphite sheets, and each layer of graphite film 9 extends along the planar direction and is stacked parallel to each other, with a single layer thickness of 10 μm to 300 μm. The metallization layer 8 is a copper, nickel, or silver layer formed on the surface of the graphite film by vacuum sputtering or electroplating. The metallization layer 8 completely covers the connecting surface of the graphite film end connecting segment 3 and extends 3 to 10 mm in the direction of the middle flexible segment 2, with a thickness of 0.3 μm to 3 μm.
[0029] In this embodiment: During operation, the heat source conducts heat to the sandwich-structured composite layer 5 through the thermally conductive metal connection end 4. The alternating stacked structure formed by the multi-layered graphite foil 6 and the thermally conductive metal sheet 7 establishes a three-dimensional heat flow network. The heat rapidly diffuses along the metallized layer 8 to the end connection section 3 of the graphite film laminate 1. Efficient in-plane heat transfer is achieved through the oriented graphite film 9 of the intermediate flexible section 2. The heat transfer hole array 10 forms a vertical heat conduction channel, allowing for bidirectional heat transfer. The metallurgical bonding interface formed by ultrasonic brazing ensures stable thermal resistance under vibration conditions. The gradient transition of the metallized layer 8 effectively alleviates thermal stress. Finally, the heat is conducted to the heat sink through the thermally conductive metal connection end 4 on the other side, achieving high heat transfer efficiency. The graphite film laminate 1 is connected to the thermally conductive metal connection end 4 through the sandwich-structured composite layer 5. The metallized layer 8 enhances the interface bonding, and the heat transfer hole array 10 optimizes vertical heat conduction. The intermediate flexible section 2 ensures structural flexibility, and ultrasonic brazing achieves metallurgical bonding, significantly reducing contact thermal resistance. This structure combines high thermal conductivity, excellent flexibility, and wide temperature range stability.
[0030] In the above technical solutions, considering that the connection between graphite materials and metal ends is usually achieved through adhesive bonding or mechanical pressing, resulting in high contact thermal resistance and severely affecting heat transfer efficiency, although the above technology uses an ultrasonic welding metal edge sealing structure, which improves the connection strength, it fails to effectively solve the problem of thermal resistance at the interface between the multilayer graphite film and the metal. To solve this problem, the specific operation is as follows:
[0031] Reference Figures 1-3 In a preferred embodiment, the planar dimensions of the thermally conductive metal sheet 7 match those of the graphite foil sheet 6, with its edge maintaining a distance of 0.1–1 mm from the edge of the graphite foil sheet 6, and its thickness ranging from 10 μm to 200 μm. In the sandwich-structured composite layer 5, the ratio of graphite foil sheet 6 to thermally conductive metal sheet 7 is 2:1 to 5:1. Solid-phase diffusion bonding is achieved between the layers through frictional heat generated by ultrasonic vibration, and the total thickness of the composite layer is 100 μm to 1000 μm. A regularly arranged array of heat transfer holes 10 is provided in the overlapping area between the graphite film 9 and the thermally conductive metal connection end 4. These heat transfer holes penetrate the graphite film laminate 1 and the metallized layer 8, with a hole diameter of 0.1 mm to 2 mm and a hole spacing of 1.5 to 3 times the hole diameter.
[0032] In this embodiment, the edge spacing design between the thermally conductive metal sheet 7 and the graphite foil sheet 6 ensures effective heat dissipation while avoiding interlayer stress concentration, thus maintaining the stability of the connection structure during long-term use. The sandwich structure composite layer 5 uses a specific ratio of alternating graphite foil sheets 6 and thermally conductive metal sheets 7, optimizing the heat conduction path while ensuring the mechanical strength of the structure, achieving a balance between thermal performance and reliability. The arrangement of the heat transfer hole array 10 significantly improves the vertical heat conduction efficiency; its regular arrangement increases the heat dissipation area while avoiding a decrease in structural strength due to openings.
[0033] Working principle: During operation, the heat source conducts heat to the sandwich structure composite layer 5 through the heat-conducting metal connection end 4. The alternating stacked structure formed by the multi-layer graphite foil 6 and the heat-conducting metal sheet 7 establishes a three-dimensional heat flow network. The heat diffuses rapidly along the metallized layer 8 to the end connection section 3 of the graphite film stack 1. Efficient in-plane heat transfer is achieved through the oriented graphite film 9 of the intermediate flexible section 2. The heat transfer hole array 10 forms a vertical heat conduction channel, allowing heat flow to be transferred in both directions. The metallurgical bonding interface formed by ultrasonic brazing ensures stable thermal resistance under vibration conditions. The gradient transition of the metallized layer 8 effectively alleviates thermal stress. Finally, the heat is conducted to the heat sink through the heat-conducting metal connection end 4 on the other side, achieving high heat transfer efficiency.
[0034] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. The substitutions may be replacements of some structures, devices, or method steps, or they may be complete technical solutions. Equivalent substitutions or modifications made based on the technical solution and inventive concept of this utility model should all be covered within the protection scope of this utility model.
Claims
1. A metal-graphite connection structure comprising a plurality of layers of a graphite film (9), characterized in that: The multilayer graphite film (9) constitutes a graphite film laminate (1). The graphite film laminate (1) includes a middle flexible section (2) and end connecting sections (3) located on both sides. Thermally conductive metal connecting ends (4) are provided on both sides of the graphite film laminate for connecting heat sources or radiators. A sandwich structure composite layer (5) is provided between the graphite film end connecting section (3) and the thermally conductive metal connecting end (4). The sandwich structure composite layer (5) is formed by alternating stacking of at least two layers of graphite foil (6) and at least one layer of thermally conductive metal sheet (7). The graphite film laminate (1) and the thermally conductive metal connecting end (4) are connected by ultrasonic brazing to form an integrated connection structure. A metallization treatment layer (8) is provided on the contact surface between the end connecting section (3) of the graphite film laminate and the thermally conductive metal connecting end (4).
2. The metal graphite connecting structure according to claim 1, wherein: The graphite film (9) is selected from pyrolytic graphite sheets. Each layer of graphite film (9) extends along the plane and is stacked parallel to each other. The thickness of a single layer is 10μm to 300μm.
3. The metal graphite connecting structure according to claim 1, wherein: The metallization layer (8) is a copper, nickel or silver layer formed on the surface of the graphite film by vacuum sputtering or electroplating. The metallization layer (8) completely covers the connecting surface of the graphite film end connecting section (3) and extends 3 to 10 mm in the direction of the middle flexible section (2), with a thickness of 0.3 μm to 3 μm.
4. The metal graphite connecting structure according to claim 1, wherein: The planar dimensions of the thermally conductive metal sheet (7) match those of the graphite foil (6), and its edge maintains a distance of 0.1 to 1 mm from the edge of the graphite foil (6), with a thickness of 10 μm to 200 μm.
5. The metal graphite connecting structure according to claim 1, wherein: The ratio of graphite foil (6) to thermally conductive metal sheet (7) in the sandwich structure composite layer (5) is 2:1 to 5:
1. Solid-phase diffusion connection is achieved between the layers through frictional heat generated by ultrasonic vibration. The total thickness of the composite layer is 100μm to 1000μm.
6. The metal graphite connecting structure according to claim 1, wherein: The overlapping area of the graphite film (9) and the heat-conducting metal connection end (4) is provided with a regularly arranged array of heat transfer holes (10). The heat transfer holes penetrate the graphite film laminate (1) and the metallization layer (8), with a hole diameter of 0.1 mm to 2 mm and a hole spacing of 1.5 to 3 times the hole diameter.