Metal graphene conductor structure and preparation method thereof

Abstract

The invention relates to the technical field of metal graphene conductor structures, in particular to a metal graphene conductor structure and a preparation method thereof, and the metal graphene conductor structure comprises a first conductor layer which comprises a first metal element; a second conductor layer including a second metal element; the first connecting layer comprises a first metal element, graphene and an intermediate metal element, and the first metal element, the graphene and the intermediate metal element are mixed to form a composite structure; wherein the first connecting layer is arranged between the first conductor layer and the second conductor layer, and the metal compatibility between the middle metal element and the first metal element and the metal compatibility between the middle metal element and the second metal element are both larger than the compatibility between the first metal element and the second metal element. The problem that in the prior art, a copper-aluminum graphene composite material is inconvenient to manufacture and unstable is solved, and the interface bonding strength, the interface internal resistance and the mechanical property of the metal graphene conductor structure are all high.

Description

Technical Field

[0001] This application relates to the technical field of metal graphene conductor structures, and more specifically, to a metal graphene conductor structure and a preparation method thereof. Background Art

[0002] Copper-aluminum composite materials have been widely used as battery electrode connectors in the field of electric vehicles due to their advantages of high electrical conductivity, high thermal conductivity of copper and light weight and low cost of aluminum. Graphene is an excellent conductor material with not only high electrical conductivity and high thermal conductivity, but also excellent properties such as high strength, high flexibility, and strong chemical inertness. Adding graphene material to copper-aluminum materials will further improve electrical and thermal conductivity and bring other property improvements.

[0003] However, it is difficult to prepare a composite material of copper, aluminum, and graphene. The first is the copper-aluminum bonding problem. In the manufacturing process of copper-aluminum, taking automotive battery electrode connectors as an example, methods such as friction welding, brazing, and casting molding are mainly used for manufacturing. However, each preparation process has certain defects and it is impossible to obtain industrial products with high reliability, good consistency, excellent connection performance, and excellent performance such as data / signal transmission. The prior art discloses cold rolling and composite forming into one body to avoid the existing welding technology, but cold rolling has weak copper-aluminum bonding force and is prone to voids in the holes, and it is impossible to obtain a copper-aluminum composite material with high reliability and good consistency in actual applications. The second is the aluminum-graphene bonding problem. The poor wettability between graphene and aluminum makes it difficult for graphene to be evenly dispersed in aluminum, and at high temperatures, aluminum and graphene are prone to carbonization reaction to form aluminum carbide that is easy to hydrolyze.

[0004] Therefore, how to manufacture copper-aluminum-graphene composite materials and improve their stability remains the focus of current research and development. Summary of the Invention

[0005] This application aims to provide a metal graphene conductor structure and a preparation method to solve the problems of inconvenient manufacture and instability of copper-aluminum-graphene composite materials in the prior art.

[0006] The embodiments of this application are implemented as follows:

[0007] In a first aspect, an embodiment of this application provides a metal graphene conductor structure, which includes:

[0008] A first conductor layer, including a first metal element;

[0009] A second conductor layer, including a second metal element;

[0010] A first connection layer, including a first metal element, graphene, and an intermediate metal element, and the first metal element, the graphene, and the intermediate metal element are mixed to form a composite structure;

[0011] Among them, the first connection layer is disposed between the first conductor layer and the second conductor layer, and the metal compatibility between the intermediate metal element and the first metal element and the metal compatibility between the intermediate metal element and the second metal element are both greater than the compatibility between the first metal element and the second metal element.

[0012] In an embodiment of the present application, the first metal element includes copper, the second metal element includes aluminum, and the intermediate metal element includes tin.

[0013] In an embodiment of the present application, in the first connection layer, the copper content is 60-70%, the graphene content is 1-3%, and the tin content is 27%-39%.

[0014] In an embodiment of the present application, the thickness of the first connection layer is less than the thickness of the first conductor layer and less than the thickness of the second conductor layer.

[0015] In an embodiment of the present application, the thickness of the first connection layer is 3-55 μm.

[0016] In an embodiment of the present application, the metal graphene conductor structure further includes:

[0017] A second connection layer, disposed between the first connection layer and the second conductor layer, the second connection layer includes an alloy of the second metal element and graphene, and the metal compatibility of the alloy of the second metal element is greater than the metal compatibility of the second metal element.

[0018] In an embodiment of the present application, the alloy of the second metal element includes 96%-98% aluminum, 0.5-1.5% nickel, 0.01-0.5% titanium, 0.5-1.2% molybdenum, 0.18-0.29% zirconium; the graphene content in the second connection layer is 1.5-3.2%.

[0019] In an embodiment of the present application, the thickness of the second connection layer is less than the thickness of the first conductor layer and less than the thickness of the second conductor layer.

[0020] In an embodiment of the present application, the thickness of the second connection layer is 5-60 μm.

[0021] In an embodiment of the present application, the metal graphene conductor structure further includes:

[0022] A graphene layer, disposed between the first conductor layer and the first connection layer.

[0023] In an embodiment of the present application, the thickness of the graphene layer is 3-8 layers.

[0024] In a second aspect, an embodiment of the present application provides a method for preparing a metal-graphene conductor structure, which includes:

[0025] S1.1, providing a copper substrate;

[0026] S2.1, providing an aluminum substrate;

[0027] S3.1, arranging a first connection layer between the copper substrate and the aluminum substrate, where the first connection layer is a composite structure formed by mixing copper, graphene, and an intermediate metal element, and the metal compatibility between the intermediate metal element and copper, as well as the metal compatibility between the intermediate metal element and aluminum, are both greater than the compatibility between the copper and the aluminum;

[0028] S4.1, hot-pressing and sintering the copper substrate, the first connection layer, and the aluminum substrate to form a metal-graphene conductor structure.

[0029] In an embodiment of the present application, in S1.1, a graphene layer is arranged on the surface of the copper substrate; in S3.1, the first connection layer is arranged on the graphene layer on the surface of the copper substrate.

[0030] In an embodiment of the present application, the intermediate metal is tin, and the first connection layer is prepared with 60 - 70% copper, 1 - 3% graphene, and 27% - 39% tin.

[0031] In an embodiment of the present application, the preparation method further includes:

[0032] S3.2, preparing a second connection layer, where the second connection layer is a composite structure composed of aluminum alloy and graphene;

[0033] In S4.1, the copper substrate, the first connection layer, the second connection layer, and the aluminum substrate are hot-pressed and sintered.

[0034] In an embodiment of the present application, in S3.2, first, an aluminum alloy with nickel, titanium, molybdenum, and cadmium is prepared according to a set mass ratio, the alloy is made into aluminum alloy powder with a particle size of 1 - 3 μm, the aluminum alloy powder is fully mixed with resin, dispersant, solvent, alumina, and graphene, and then dried under inert gas protection to form a mixed powder with graphene-coated aluminum alloy; then, under the condition of 400 - 450 °C, the mixed powder is pressed into a green body and sintered.

[0035] In an embodiment of the present application, in S3.2, the resin concentration is 25 - 40%, the dispersant is 1 - 2% polyvinyl alcohol, the solvent is n-hexane or cyclohexane, the alumina content is 0.5 - 1%, and the graphene content is 1.5 - 3.2%.

[0036] In one embodiment of the present application, in S4.1, the conditions for hot pressing and sintering to form the metal graphene conductor structure include: the hot pressing control pressure is 200 - 800 KN, the temperature is 400 - 450 °C, and the heat preservation time is 5 - 20 min.

[0037] Beneficial effects of the present invention: First, a first connection layer of a composite structure is formed by the first metal element (copper), the intermediate metal element, and graphene, enabling better mixing of the graphene material and copper. Then, taking advantage of the good compatibility of the intermediate metal element with copper and aluminum, the first conductor layer (copper matrix) and the second conductor layer (aluminum matrix) can be hot pressed and connected through the first connection layer without requiring too high hot pressing or casting temperature, alleviating the problem of forming intermediate compounds between copper and aluminum at high temperatures, and effectively solving the problem of the carbonization reaction between graphene and aluminum, thereby forming a stable metal graphene composite structure and solving the problems of inconvenient manufacturing and instability of copper-aluminum-graphene composite materials in the prior art.

[0038] By providing a second connection layer (aluminum alloy graphene) between the first connection layer and the second conductor layer (aluminum matrix), the second connection layer plays a transitional role, making it easier to connect the first connection layer and the second conductor layer, further solving the problem of carbonization reaction caused by the need for a high temperature during the hot pressing process. Moreover, the tin in the first connection layer is prone to form a eutectic melt with aluminum, playing a good connection role, and the tin will also partially penetrate into the aluminum alloy layer, further preventing the formation of intermediate compounds between aluminum and copper. In addition, graphene can be more evenly dispersed in the aluminum alloy, effectively improving the electrical conductivity and flexibility.

[0039] Furthermore, by providing a graphene layer between the first conductor layer and the first connection layer, the graphene content in the metal graphene conductor structure is increased, making the conductor structure lighter in mass, better in strength and flexibility, and enhancing the electrical conductivity.

[0040] The technical solution of the present application solves the problems of inconvenient manufacturing and instability of copper-aluminum-graphene composite materials in the prior art, and provides a metal graphene conductor structure with high interfacial bonding strength, low interfacial internal resistance, and good mechanical properties. Description of the Drawings

[0041] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a cross-sectional view of the metal graphene conductor structure provided by an embodiment of the present application.

[0043] Icons: 1 - First conductor layer; 2 - Second conductor layer; 3 - First connection layer; 4 - Second connection layer; 5 - Graphene layer. Detailed implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application that is claimed, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0046] In the description of this application, terms such as "first" and "second" are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0047] In this application, "and / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: the existence of A, the simultaneous existence of A and B, and the existence of B. Where A and B can be singular or plural.

[0048] In this application, "at least one" means one or more, and "multiple" means two or more. "At least one kind", "at least one item (piece) below" or similar expressions refer to any combination of these items, including any combination of single item (piece) or plural items (pieces). For example, "at least one item (piece) among a, b, or c", or, "at least one item (piece) among a, b, and c" can both represent: a, b, c, a - b (that is, a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0049] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0050] It should be noted that: Similar reference numerals and letters denote similar items in the following figures; thus, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] The present application provides a metal graphene conductor structure and a preparation method thereof, which are used to solve the problems that the copper-aluminum graphene composite material in the prior art is inconvenient to manufacture and unstable.

[0052] As Figure 1 shown, the metal graphene conductor structure includes a first conductor layer 1, a second conductor layer 2, and a first connection layer 3, and the first connection layer 3 is disposed between the first conductor layer 1 and the second conductor layer 2.

[0053] Wherein, the first connection layer 3 is a composite structure formed by mixing a first metal element, graphene, and an intermediate metal element, and the metal compatibility between the intermediate metal element and the first metal element and the metal compatibility between the intermediate metal element and the second metal element are both greater than the compatibility between the first metal element and the second metal element.

[0054] The first conductor layer 1 includes a first metal element. The second conductor layer 2 includes a second metal element. The first metal element and the second metal element are two different metal elements.

[0055] The following takes the first metal element as copper and the second metal element as aluminum for detailed description. The technical solution of the present application is also applicable to other first metal elements and other second metal elements that are not easily combined in similar situations, and the situation where the second metal element and graphene are not easily stably combined. In the prior art, for example, in battery electrode connectors, copper-aluminum materials are mainly connected by technologies such as friction welding, brazing, and casting molding. The manufacturing methods of friction welding and brazing have certain defects in terms of preparation process, connection performance, and manufacturing cost. In the casting molding method, a relatively high temperature (>650 °C) is required to facilitate the formation of good interfacial bonding strength between the copper and aluminum phases. However, on the one hand, the process conditions of this manufacturing method are demanding and it is easy to form copper-aluminum intermediate compounds (such as hard and brittle phases like Cu / Al, Cu4Al3, and Au3Al2), resulting in defects such as reduced bonding strength and high interfacial internal resistance; on the other hand, graphene materials cannot be added to it, and graphene and aluminum will undergo a carbonization reaction at high temperatures to generate aluminum carbide that is prone to hydrolysis. There is also a cold pressing molding method in the prior art. However, the bonding interface of cold pressing molding is relatively unstable. If the bonding strength is to be improved, additional surface processing is required, and the process is complex.

[0056] The technical solution provided by the embodiments of the present application first forms a first connection layer 3 with a composite structure of the first metal element (copper), the intermediate metal element, and graphene, so that the graphene material is better mixed with copper. Then, taking advantage of the good compatibility of the intermediate metal element with copper and aluminum, without the need for too high a hot pressing or casting temperature, the first conductor layer 1 (copper substrate) and the second conductor layer 2 (aluminum substrate) can be hot pressed and connected through the first connection layer 3, alleviating the problem of the formation of intermediate compounds between copper and aluminum at high temperatures, and effectively solving the problem of the carbonization reaction between graphene and aluminum, thereby forming a stable metal-graphene composite structure and solving the problems that the copper-aluminum-graphene composite material in the prior art is inconvenient to manufacture and unstable.

[0057] In some embodiments, the intermediate metal element includes tin. In other embodiments, the intermediate metal element may also include titanium, gallium, etc.

[0058] The first connection layer 3 composed of tin, copper, and graphene not only has excellent electrical and thermal conductivity, but also has good structural strength and stiffness. At the same time, graphene is easy to disperse in the copper-tin alloy, and the structure is stable.

[0059] Among them, in the first connection layer 3, the copper content is 60-70%, the graphene content is 1-3%, and the tin content is 27%-39%. Within this ratio range, the metal compatibility is good, and the overall melting point of the metal in the first connection layer 3 is within a suitable range, neither too high to cause difficulty in forming a good hot pressing bonding interface, nor too low to cause excessive fluidity, which plays a role in improving the overall connection stability of the conductor structure.

[0060] In some embodiments, the thickness of the first connection layer 3 is less than the thickness of the first conductor layer 1 and less than the thickness of the second conductor layer 2, so that the overall content of tin in the metal graphene conductor structure is relatively low, ensuring good electrical conductivity, thermal conductivity and low cost.

[0061] Exemplarily, the thickness of the first connection layer 3 is 3 - 55 μm. Within this thickness range, the first connection layer 3 plays a good connection role, forming a composite material with good thermal conductivity and electrical conductivity, and with low manufacturing cost.

[0062] In some embodiments, the metal graphene conductor structure further includes a second connection layer 4. The second connection layer 4 is disposed between the first connection layer 3 and the second conductor layer 2. The second connection layer 4 includes an alloy of a second metal element (hereinafter referred to as the second metal alloy) and graphene, and the metal compatibility of the second metal alloy is greater than the metal compatibility of the second metal element.

[0063] Taking the second metal element as aluminum as an example, the second connection layer 4 is a composite structure formed by aluminum alloy and graphene. By disposing the second connection layer 4 (aluminum alloy graphene) between the first connection layer 3 and the second conductor layer 2 (aluminum substrate), the second connection layer 4 plays a transitional role. By adding other elements to aluminum to increase its metal compatibility, the first connection layer 3 and the second conductor layer 2 can be more easily connected, further solving the problem of carbonization reaction caused by the need for a higher temperature during the hot pressing process. Moreover, the tin in the first connection layer 3 is easily melted with aluminum to form a eutectic, playing a good connection role, and tin will also partially penetrate into the aluminum alloy layer, further preventing aluminum from forming intermediate compounds with copper. In addition, graphene can be more evenly dispersed in the aluminum alloy, effectively improving electrical conductivity and flexibility.

[0064] In some embodiments, the content of graphene in the second connection layer 4 is 1.5 - 3.2%, improving electrical conductivity while ensuring connectivity.

[0065] In some embodiments, the second metal alloy includes 96% - 98% aluminum, 0.5 - 1.5% nickel, 0.01 - 0.5% titanium, 0.5 - 1.2% molybdenum, 0.18 - 0.29% zirconium. By adding nickel, titanium, molybdenum and zirconium in the above proportions, not only the transitional connection effect of the second connection layer 4 is improved, but also the strength, hardness, crack resistance, ductility and corrosion resistance of the second connection layer 4 can be improved, thereby improving the overall mechanical properties of the metal graphene conductor structure.

[0066] In some embodiments, the thickness of the second connection layer 4 is less than the thickness of the first conductor layer 1 and less than the thickness of the second conductor layer 2, so that the content of precious metals in the metal graphene conductor structure is low, ensuring good electrical conductivity, thermal conductivity and low cost.

[0067] Exemplarily, the thickness of the second connection layer 4 is 5 - 60 μm. Within this thickness range, the first connection layer 3 plays a good connection role, forming a composite material with good thermal conductivity and electrical conductivity, and with a relatively low manufacturing cost.

[0068] Furthermore, in some embodiments, the metal graphene conductor structure further includes a graphene layer 5, which is disposed between the first conductor layer 1 and the first connection layer 3. Without affecting the connection strength, it increases the graphene content in the metal graphene conductor structure, making the conductor structure lighter in mass, better in strength and flexibility, and enhancing the electrical conductivity. Among them, the thickness of the graphene layer 5 is 3 - 8 layers, and the thickness of a single-layer graphene is approximately 0.0344 nm.

[0069] A preparation method of a metal graphene conductor structure provided by an embodiment of the present application includes:

[0070] S1.1, providing a first conductor layer 1, such as a copper substrate, and the first metal element is copper;

[0071] S2.1, providing a second conductor layer 2, such as an aluminum substrate, and the second metal element is aluminum;

[0072] S3.1, disposing a first connection layer 3 between the copper substrate and the aluminum substrate, and the first connection layer 3 is a composite structure formed by mixing copper, graphene, and an intermediate metal element, and the metal compatibility between the intermediate metal element and copper, and the metal compatibility between the intermediate metal element and aluminum are both greater than the compatibility between copper and aluminum;

[0073] S4.1, hot-pressing and sintering the copper substrate, the first connection layer 3, and the aluminum substrate to form a metal graphene conductor structure.

[0074] Optionally, in S1.1, a graphene layer 5 is disposed on the surface of the copper substrate; in S3.1, the first connection layer 3 is disposed on the graphene layer 5 on the surface of the copper substrate.

[0075] In some embodiments, the graphene layer 5 is formed on the surface of the copper substrate by chemical vapor deposition. For example, under the condition of a protective gas, the copper surface is heated to 1000 - 1060 °C, and a carbon-containing gas at a temperature of 1000 - 1060 °C is introduced to form a graphene layer 5 on the copper surface. Among them, the protective gas is at least one of nitrogen and argon, and the flow rate is 0 - 1000 sccm; in addition, the protective gas contains hydrogen with a flow rate of 10 - 500 sccm; the carbon-containing gas can be methane gas, and the flow rate is 5 - 50 sccm.

[0076] In some embodiments, the intermediate metal is tin, and the first connection layer 3 is prepared with 60 - 70% copper, 1 - 3% graphene, and 27% - 39% tin. Exemplarily, an electrolyte containing copper ions, tin ions, and graphene is configured, and a current is applied to electroplatingly deposit the copper ions, tin ions, and graphene on the surface of the first conductor layer 1 or the surface of the graphene layer 5, thereby forming the first connection layer 3 mixed with copper, tin, and graphene.

[0077] In some embodiments, the method for preparing the metal graphene conductor structure further includes:

[0078] S3.2. Prepare the second connection layer 4, which is a composite structure composed of aluminum alloy and graphene; in S4.1, stack the copper substrate, the first connection layer 3, the second connection layer 4, and the aluminum substrate in sequence and perform hot pressing and sintering.

[0079] Specifically, in S3.2, first prepare an alloy of aluminum with nickel, titanium, molybdenum, and zirconium according to a set mass ratio, prepare the alloy into aluminum alloy powder with a particle size of 1 - 3 μm, fully mix the aluminum alloy powder with resin, dispersant, solvent, alumina, and graphene, and then dry it under the protection of inert gas to form a mixed powder with graphene-coated aluminum alloy; then, at 400 - 450 °C, press the mixed powder into a green body and sinter it.

[0080] During the sintering process of preparing the second connection layer 4 in S3.2, organic substances such as resin will be carbonized to produce part of carbon, and the generated carbon will react with alumina to generate aluminum and consume carbon. In this way, the graphene in the second connection layer 4 is evenly dispersed, and it is not easy for graphene and aluminum to undergo a carbonization reaction.

[0081] Among them, the set mass ratio is 96% - 98% aluminum, 0.5 - 1.5% nickel, 0.01 - 0.5% titanium, 0.5 - 1.2% molybdenum, and 0.18 - 0.29% zirconium.

[0082] Among them, the resin concentration is 25 - 40%, the dispersant is 1 - 2% polyvinyl alcohol, the solvent is n-hexane or cyclohexane, the alumina content is 0.5 - 1%, and the graphene content is 1.5 - 3.2%.

[0083] In some embodiments, in S4.1, the conditions for hot pressing and sintering to form the metal graphene conductor structure include: the hot pressing control pressure is 200 - 800 KN, the temperature is 400 - 450 °C, and the heat preservation time is 5 - 20 min. Under these conditions, the copper substrate and the aluminum substrate with the graphene layer 5 on the surface can be well connected through the first connection layer 3 (copper-tin-graphene) and the second connection layer 4 (aluminum alloy-graphene), forming a good bonding interface, and can also alleviate the problem of the formation of intermediate compounds between copper and aluminum, as well as solve the problem of the carbonization reaction between graphene and aluminum.

[0084] The following are specific embodiments of the present application.

[0085] Embodiment 1

[0086] S1.1, Provide a copper substrate;

[0087] S2.1, Provide an aluminum substrate;

[0088] S3.1, Configure an electrolyte containing copper ions, tin ions and graphene, apply a current to electroplate and deposit the copper ions, tin ions and graphene on the surface of the first conductor layer or the surface of the graphene layer, thereby forming a first connection layer. The first connection layer includes 62% copper, 1% graphene, 37% tin, and the thickness of the prepared first connection layer is 20 μm;

[0089] S4.1, Under the conditions of 200 - 800 KN and 450 °C, hot-press and sinter the copper substrate, the first connection layer and the aluminum substrate to form a metal-graphene conductor structure, and keep it warm for 5 - 20 min.

[0090] Embodiment 2

[0091] S1.1, Provide a copper substrate;

[0092] S2.1, Provide an aluminum substrate;

[0093] S3.1, Configure an electrolyte containing copper ions, tin ions and graphene, apply a current to electroplate and deposit the copper ions, tin ions and graphene on the surface of the first conductor layer or the surface of the graphene layer, thereby forming a first connection layer. The first connection layer includes 69% copper, 3% graphene, 28% tin, and the thickness of the prepared first connection layer is 45 μm;

[0094] S4.1, Under the conditions of 200 - 800 KN and 450 °C, hot-press and sinter the copper substrate, the first connection layer and the aluminum substrate to form a metal-graphene conductor structure, and keep it warm for 5 - 20 min.

[0095] Embodiment 3

[0096] S1.1, Provide a copper substrate;

[0097] S2.1, Provide an aluminum substrate;

[0098] S3.1, Configure an electrolyte containing copper ions, tin ions and graphene, apply a current to electroplate and deposit the copper ions, tin ions and graphene on the surface of the first conductor layer or the surface of the graphene layer, thereby forming a first connection layer. The first connection layer includes 62% copper, 1% graphene, 37% tin, and the thickness of the prepared first connection layer is 20 μm;

[0099] S3.2. First, prepare an alloy of aluminum with nickel, titanium, molybdenum, and zirconium according to the set mass ratio. The set mass ratio is 96% aluminum, 0.5% nickel, 0.02% titanium, 0.5% molybdenum, and 0.2% zirconium. Then, prepare the alloy into aluminum alloy powder with a particle size of 1 - 3 μm. After fully mixing the aluminum alloy powder with 30% resin, 1% polyvinyl alcohol dispersant by concentration, a solvent (at least one of n - hexane and cyclohexane), 1% alumina, and 1.78% graphene, dry it under the protection of inert gas to form a mixed powder with graphene - coated aluminum alloy. Then, at 400 - 450 °C, press the mixed powder into a green body and sinter it to form a second bonding layer with a thickness of 20 μm.

[0100] S4.1. At 200 - 800 KN and 450 °C, hot - press and sinter the copper substrate, the first bonding layer, the second bonding layer, and the aluminum substrate to form a metal - graphene conductor structure, and keep it warm for 5 - 20 min.

[0101] Example 4

[0102] S1.1. Provide a copper substrate;

[0103] S2.1. Provide an aluminum substrate;

[0104] S3.1. Configure an electrolyte containing copper ions, tin ions, and graphene. Apply current to electro - deposit copper ions, tin ions, and graphene on the surface of the first conductor layer or the surface of the graphene layer, thereby forming a first bonding layer. The first bonding layer includes 62% copper, 1% graphene, and 37% tin. The thickness of the prepared first bonding layer is 20 μm.

[0105] S3.2. First, prepare an alloy of aluminum with nickel, titanium, molybdenum, and zirconium according to the set mass ratio. The set mass ratio is 97% aluminum, 0.6% nickel, 0.01% titanium, 0.6% molybdenum, and 0.25% zirconium. Then, prepare the alloy into aluminum alloy powder with a particle size of 1 - 3 μm. After fully mixing the aluminum alloy powder with 35% resin, 2% polyvinyl alcohol dispersant by concentration, a solvent (at least one of n - hexane and cyclohexane), 1% alumina, and 1.54% graphene, dry it under the protection of inert gas to form a mixed powder with graphene - coated aluminum alloy. Then, at 400 - 450 °C, press the mixed powder into a green body and sinter it to form a second bonding layer with a thickness of 50 μm.

[0106] S4.1. At 200 - 800 KN and 450 °C, hot - press and sinter the copper substrate, the first bonding layer, and the aluminum substrate to form a metal - graphene conductor structure, and keep it warm for 5 - 20 min.

[0107] Example 5

[0108] S1.1, Provide a copper substrate, and under the condition of protective gas, heat the copper surface to 1000 - 1060 °C, and introduce a carbon-containing gas at a temperature of 1000 - 1060 °C to form 3 - 8 layers of graphene layers on the copper surface; wherein, the protective gas is at least one of nitrogen and argon, with a flow rate of 0 - 1000 sccm; in addition, the protective gas contains hydrogen with a flow rate of 10 - 500 sccm; the carbon-containing gas can be methane gas, with a flow rate of 5 - 50 sccm;

[0109] S2.1, Provide an aluminum substrate;

[0110] S3.1, Configure an electrolyte containing copper ions, tin ions and graphene, apply a current to electroplate and deposit the copper ions, tin ions and graphene on the surface of the first conductor layer or the surface of the graphene layer, thereby forming a first connection layer. The first connection layer includes 62% copper, 1% graphene, and 37% tin, and the prepared first connection layer has a thickness of 20 μm;

[0111] S4.1, Under the conditions of 200 - 800 KN and 450 °C, hot-press and sinter the copper substrate with graphene layers, the first connection layer and the aluminum substrate to form a metal graphene conductor structure, and keep it warm for 5 - 20 min.

[0112] Example 6

[0113] S1.1, Provide a copper substrate, and under the condition of protective gas, heat the copper surface to 1000 - 1060 °C, and introduce a carbon-containing gas at a temperature of 1000 - 1060 °C to form 3 - 8 layers of graphene layers on the copper surface; wherein, the protective gas is at least one of nitrogen and argon, with a flow rate of 0 - 1000 sccm; in addition, the protective gas contains hydrogen with a flow rate of 10 - 500 sccm; the carbon-containing gas can be methane gas, with a flow rate of 5 - 50 sccm;

[0114] S2.1, Provide an aluminum substrate;

[0115] S3.1, Configure an electrolyte containing copper ions, tin ions and graphene, apply a current to electroplate and deposit the copper ions, tin ions and graphene on the surface of the first conductor layer or the surface of the graphene layer, thereby forming a first connection layer. The first connection layer includes 62% copper, 1% graphene, and 37% tin, and the prepared first connection layer has a thickness of 20 μm;

[0116] S3.2. First, prepare an aluminum alloy with nickel, titanium, molybdenum, and zirconium according to the set mass ratio. The set mass ratio is 96% aluminum, 0.5% nickel, 0.02% titanium, 0.5% molybdenum, and 0.2% zirconium. Then, prepare the alloy into aluminum alloy powder with a particle size of 1 - 3 μm. After fully mixing the aluminum alloy powder with 30% resin, 1% polyvinyl alcohol dispersant by concentration, a solvent (at least one of n - hexane and cyclohexane), 1% alumina, and 1.78% graphene, dry it under the protection of inert gas to form a mixed powder with graphene - coated aluminum alloy. Then, at 400 - 450 °C, press the mixed powder into a green body and sinter it to form a second bonding layer with a thickness of 20 μm.

[0117] S4.1. Under the conditions of 200 - 800 KN and 450 °C, hot - press and sinter the copper substrate with a graphene layer, the first bonding layer, and the aluminum substrate to form a metal - graphene conductor structure, and keep it warm for 5 - 20 min.

[0118] Comparative Example 1

[0119] 1). Synthesize Cu nano - sol particles with uniform size and controllable morphology through the sol - gel method.

[0120] Weigh a certain amount of copper acetate and prepare a 0.01 mol / L, 250 mL aqueous solution of copper ions (Cu2+). Add 0.01% mol surfactant stearic acid based on the total molar amount of raw materials to the aqueous solution of copper ions. After the stearic acid is evenly dissolved in the aqueous solution of copper ions, add 125 mL of glycerol to the aqueous solution of copper ions for sol reaction. Control the sol reaction temperature at 150 °C and the continuous reaction time at 5 h. After the reaction ends, centrifuge and wash the obtained product to finally obtain Cu nano - sol particles with uniform particle size. In the specific implementation process, the sol reaction temperature can be adjusted in the range of 70 - 150 °C, and the continuous reaction time can be adjusted in the range of 1 - 5 h.

[0121] 2). Uniformly spray the Cu nano - sol particles onto the surface of a Cu metal sheet by cold - spraying technology, and form rich active sites through in - situ etching to construct a three - dimensional rough structure on the Cu metal surface to obtain a Cu metal sheet with in - situ activated etching on the surface. Adjust the spraying process parameters used in the cold - spraying technology: spraying air pressure 5.5 MPa, spraying gas temperature 80 °C, spraying distance 30 mm, and relative moving speed of the substrate 10 cm / s. In the specific implementation process, the spraying process parameters can be adjusted within the following ranges: spraying air pressure 1.5 - 5.5 MPa, spraying gas temperature 25 - 80 °C, spraying distance 10 - 30 mm, and relative moving speed of the substrate 2 - 10 cm / s.

[0122] 3) Then, the surface-in-situ-activated and etched Cu metal sheet and the Al metal sheet are subjected to cold rolling composite solid-state connection to obtain a copper-aluminum composite material. The cold rolling process parameters are as follows: rolling force 30 cN, rolling rate 0.3 m / s, and annealing temperature 450 °C. Using the above parameters in the cold rolling process can improve the mechanical properties of the copper-aluminum composite material. In the specific implementation process, the process parameters such as the rolling force magnitude, rolling rate, and annealing temperature of the cold rolling process can be adjusted within the following parameter ranges: rolling force 10 - 30 cN, rolling rate 0.01 - 0.3 m / s, and annealing temperature 200 - 450 °C.

[0123] The composite conductor structures prepared in Examples 1, 2, 3, 4, 5, 6 and Comparative Example 1 are tested under the test conditions, and their interfacial bonding strength, interfacial internal resistance, and mechanical properties are shown in Table 1.

[0124]

[0125] As can be seen from Table 1, compared with the cold-pressed copper-aluminum composite structure in Comparative Example 1, Examples 1 - 6 show better bonding strength, resistivity, and tensile strength. Although the method used in Comparative Example 1 improves the interfacial bonding strength of cold-pressed copper-aluminum to a certain extent and avoids the defects of high interfacial internal resistance and poor mechanical properties caused by hot pressing, its mechanical properties are still inferior to the hot pressing effect of the examples in this application. Moreover, it is not convenient to add graphene, and it is impossible to achieve uniform dispersion and stable combination of graphene, and its conductivity is also inferior to that of the examples in this application. The comparison shows that the technical solution provided by the examples in this application realizes the preparation of a metal-graphene conductor structure through a hot pressing process, alleviates the problems of copper-aluminum mutual melting and graphene-aluminum carbide reaction, and improves conductivity, structural stability, and mechanical properties. Comparing Example 1 with Example 2 shows that the component ratio and thickness of the first connection layer can be flexibly adjusted within a certain range. Comparing Example 1 with Examples 3 and 4 shows that adding a second connection layer between the first connection layer and the aluminum matrix can improve the structural strength and mechanical properties of the composite structure to a certain extent, and at the same time, the conductivity can also be maintained within a relatively high range, and the component ratio and thickness of the second connection layer can be flexibly adjusted within a certain range. Comparing Example 1 with Example 5 shows that adding a graphene layer between the copper matrix and the first connection layer can improve the electrical conductivity, and at the same time, the structural strength and mechanical properties of the composite structure can also be maintained within a relatively high range. Comparing Example 1 with Example 6 shows that adding a graphene layer on the side of the first connection layer close to the copper matrix and adding a second connection layer on the side of the first connection layer close to the aluminum matrix can further improve the structural strength and mechanical properties on the basis of maintaining high conductivity.

[0126] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A metal-graphene conductor structure, characterized in that, it includes: A first conductor layer, including a first metal element; A second conductor layer, including a second metal element; A first connection layer, including the first metal element, graphene, and an intermediate metal element, where the first metal element, the graphene, and the intermediate metal element are mixed to form a composite structure; wherein, the first connection layer is disposed between the first conductor layer and the second conductor layer, and the metal compatibility between the intermediate metal element and the first metal element, and the metal compatibility between the intermediate metal element and the second metal element are both greater than the metal compatibility between the first metal element and the second metal element.

2. The metal-graphene conductor structure according to claim 1, characterized in that, the first metal element includes copper, the second metal element includes aluminum, and the intermediate metal element includes tin.

3. The metal-graphene conductor structure according to claim 2, characterized in that, in the first connection layer, the copper content is 60 - 70%, the graphene content is 1 - 3%, and the tin content is 27% - 39%.

4. The metal-graphene conductor structure according to claim 1, characterized in that, the thickness of the first connection layer is less than the thickness of the first conductor layer and less than the thickness of the second conductor layer; the thickness of the first connection layer is 3 - 55 μm.

5. The metal-graphene conductor structure according to any one of claims 1 - 4, characterized in that, it further includes: A second connection layer, disposed between the first connection layer and the second conductor layer, the second connection layer includes an alloy of the second metal element and graphene, and the metal compatibility of the alloy of the second metal element is greater than the metal compatibility of the second metal element.

6. The metal-graphene conductor structure according to claim 5, characterized in that, the alloy of the second metal element includes 96% - 98% aluminum, 0.5 - 1.5% nickel, 0.01 - 0.5% titanium, 0.5 - 1.2% molybdenum, 0.18 - 0.29% zirconium; the graphene content in the second connection layer is 1.5 - 3.2%.

7. The metal-graphene conductor structure according to claim 5, characterized in that, the thickness of the second connection layer is less than the thickness of the first conductor layer and less than the thickness of the second conductor layer; the thickness of the second connection layer is 5 - 60 μm.

8. The metal-graphene conductor structure according to claim 1, characterized in that, it further includes: A graphene layer, disposed between the first conductor layer and the first connection layer.

9. The metal-graphene conductor structure according to claim 8, characterized in that, the thickness of the graphene layer is 3 - 8 layers.

10. A preparation method of a metal-graphene conductor structure, characterized in that, it includes: S1.1, providing a copper substrate; S2.1, providing an aluminum substrate; S3.

1. Set a first connection layer between the copper substrate and the aluminum substrate. The first connection layer is a composite structure formed by mixing copper, graphene, and an intermediate metal element. The metal compatibility between the intermediate metal element and copper, and the metal compatibility between the intermediate metal element and aluminum are both greater than the compatibility between copper and aluminum. S4.

1. Hot press and sinter the copper substrate, the first connection layer, and the aluminum substrate to form a metal-graphene conductor structure.

11. The method for preparing the metal-graphene conductor structure according to claim 10, characterized in that, in S1.1, a graphene layer is set on the surface of the copper substrate; in S3.1, the first connection layer is set on the graphene layer on the surface of the copper substrate.

12. The method for preparing the metal-graphene conductor structure according to claim 10 or 11, characterized in that, the intermediate metal element is tin, and the first connection layer is prepared with 60-70% copper, 1-3% graphene, and 27%-39% tin.

13. The method for preparing the metal-graphene conductor structure according to claim 10, characterized in that, further comprising: S3.

2. Prepare a second connection layer, which is a composite structure composed of aluminum alloy and graphene; in S4.1, hot press and sinter the copper substrate, the first connection layer, the second connection layer, and the aluminum substrate.

14. The method for preparing the metal-graphene conductor structure according to claim 13, characterized in that, in S3.2, first prepare an aluminum alloy with nickel, titanium, molybdenum, and cadmium according to a set mass ratio, prepare the alloy into aluminum alloy powder with a particle size of 1-3 μm, fully mix the aluminum alloy powder with resin, dispersant, solvent, alumina, and graphene, and dry it under the protection of inert gas to form a mixed powder with graphene-coated aluminum alloy; then, at 400-450 °C, press the mixed powder into a green body and sinter it.

15. The method for preparing the metal-graphene conductor structure according to claim 14, characterized in that, in S3.2, the resin concentration is 25-40%, the dispersant is 1-2% polyvinyl alcohol, the solvent is n-hexane or cyclohexane, the alumina content is 0.5-1%, and the graphene content is 1.5-3.2%.

16. The method for preparing the metal-graphene conductor structure according to claim 10, characterized in that, in S4.1, the conditions for hot press sintering to form the metal-graphene conductor structure include: the hot press control pressure is 200-800 KN, the temperature is 400-450 °C, and the heat preservation time is 5-20 min.

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