Composite conductor, preparation method therefor and conductive element

Abstract

The present application provides a composite conductor, a preparation method therefor, and a conductive element. The preparation method comprises: providing conductive paste, the conductive paste comprising metal powder and a reagent, and the reagent comprising resin and a polar compound; applying an electric field to the conductive paste to obtain a composite conductor precursor; coating the composite conductor precursor with a graphene layer to obtain a composite conductor preform; and hot-pressing the composite conductor preform to obtain a composite conductor. The composite conductor prepared in the present application exhibits high conductivity.

Description

Composite conductor and preparation method thereof, and conductive element

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 11, 2023, with application number 202311687648.6 and application name “Composite conductor, preparation method thereof, and conductive element”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of conductor technology, and in particular to a composite conductor, a preparation method thereof, and a conductive element. Background Art

[0003] Graphene has excellent properties such as high electrical conductivity, high thermal conductivity, high strength, high flexibility, strong chemical inertness, and excellent gas barrier properties. It is widely used in various fields, especially in the field of conductor technology. Graphene can significantly improve the electrical conductivity of metals (such as copper and copper alloys).

[0004] Existing metal powders, such as copper powder, usually have various irregular shapes, including tree-like, rod-like, or spherical shapes with various protrusions or grooves. Currently, these powders of different shapes are usually mixed and forced to deform through methods such as hot pressing to finally form the desired finished product. However, the conductive elements inside the finished conductor are still these irregular powder units. Moreover, due to the different shapes of each powder unit, its internal electron arrangement is different, resulting in different conductive arrangements between powders. Not only can the arrangement of some powders not play a good conductive role, but the magnetic field generated by its arrangement will also hinder the transmission of electrons, resulting in a decrease in the conductive performance of the surrounding powders.

[0005] Existing processing methods cannot achieve optimal alignment of individual powders for conductivity. Despite the addition of highly conductive graphene, the overall improvement in the conductor's conductivity is limited due to the amount of graphene added and the arrangement of the copper conductors. Therefore, further research is needed to determine how to arrange metal powders in the optimal conductive direction to produce highly conductive finished conductors. SUMMARY OF THE INVENTION

[0006] The present application provides a composite conductor, a preparation method thereof, and a conductive element.

[0007] The present application provides a method for preparing a composite conductor, comprising:

[0008] Providing a conductive paste, the conductive paste comprising metal powder and a reagent, the reagent comprising a resin and a polar compound;

[0009] applying an electric field to the conductive paste to obtain a composite conductor precursor;

[0010] coating the composite conductor precursor with a graphene layer to obtain a composite conductor preform;

[0011] The composite conductor preform is subjected to hot pressing treatment to obtain a composite conductor.

[0012] Optionally, in some embodiments of the present application, the method of applying an electric field includes: allowing the conductive paste to flow through the electric field.

[0013] Optionally, in some embodiments of the present application, the method of causing the conductive paste to flow through the electric field includes: placing the conductive paste in a 3D printing device, and setting an electric field at the outlet of the 3D printing device; the distance between the electric field and the outlet of the 3D printing device is 2 cm to 8 cm.

[0014] Optionally, in some embodiments of the present application, the method of applying an electric field includes: providing a mold, placing the conductive paste in the mold, and applying an electric field to the mold.

[0015] Optionally, in some embodiments of the present application, the electric field strength is 100 V / cm~260 V / cm; and the power source of the electric field is direct current or alternating current.

[0016] Optionally, in some embodiments of the present application, the material of the metal powder includes one or more of copper, silver, copper alloy, and silver alloy; the shape of the metal powder includes one or more of dendritic, rod-shaped, flake-shaped, cubic, spherical, or nearly spherical; and the average particle size is 10 μm to 100 μm.

[0017] Optionally, in some embodiments of the present application, the resin includes one or more of epoxy resin, acrylic resin, amino resin, alkyd resin, polyurethane resin, cyclic silicone resin, and fluorocarbon resin; and / or

[0018] The polar compound includes one or more of methanol, ethanol, formamide, trifluoroacetic acid, DMSO, acetonitrile, DMF, hexamethylphosphoramide, acetic acid, propanol, pyridine, tetramethylethylenediamine, acetone, and triethylamine.

[0019] Optionally, in some embodiments of the present application, the mass fraction of the metal powder in the conductive paste is 40% to 60%; and / or

[0020] The mass ratio of the resin to the polar compound is (10-30):(5-10).

[0021] Optionally, in some embodiments of the present application, the reagent further includes a solvent; the solvent includes one or more of tetrahydrofuran, benzene, toluene, xylene, and n-butanol; and the mass ratio of the resin to the solvent is (10~30): (15~35).

[0022] Optionally, in some embodiments of the present application, the reagent further includes an auxiliary carbon source; the auxiliary carbon source includes one or more of phenanthrene, anthracene, naphthalene, and polymethyl methacrylate; and the mass ratio of the resin to the auxiliary carbon source is (10~30): (1~3).

[0023] Optionally, in some embodiments of the present application, the reagent further includes a metal oxide; the metal oxide includes one or more of copper oxide and silver oxide; and the mass ratio of the resin to the metal oxide is (10~30):(0.1~10).

[0024] Optionally, in some embodiments of the present application, the reagent further includes a curing agent; the curing agent includes one or more of an amine curing agent and an acid anhydride curing agent; the amine curing agent includes one or more of a polyamide curing agent, an aliphatic amine curing agent, an aromatic amine curing agent, an alicyclic amine curing agent, a polyether amine curing agent, and an imidazole curing agent; the acid anhydride curing agent includes one or more of an aromatic anhydride curing agent, an aliphatic anhydride curing agent, and an alicyclic anhydride curing agent; the mass ratio of the resin to the curing agent is (10~30):(0.1~15).

[0025] Optionally, in some embodiments of the present application, coating the composite conductor precursor with a graphene layer includes: introducing a protective gas and performing a first heat treatment to obtain a carbide.

[0026] Optionally, in some embodiments of the present application, the temperature of the first heat treatment is 500° C. to 700° C.; the time of the first heat treatment is 20 min to 38 min; and / or

[0027] The first heat treatment is performed in a vacuum environment, the vacuum degree of the vacuum environment is 10 -3 kPa; and / or

[0028] The protective gas includes one or more of nitrogen, helium, argon, xenon, krypton, neon, and radon.

[0029] Optionally, in some embodiments of the present application, after obtaining the carbide, the process further includes: introducing an auxiliary gas and performing a second heat treatment to obtain a graphene layer.

[0030] Optionally, in some embodiments of the present application, the temperature of the second heat treatment is 800° C. to 1050° C.; the time of the second heat treatment is 20 min to 50 min; and / or

[0031] The auxiliary gas includes hydrogen; the gas flow rate of the auxiliary gas is 10 sccm~500 sccm; and / or

[0032] The number of graphene layers is 3 to 8.

[0033] Optionally, in some embodiments of the present application, the temperature of the hot pressing treatment of the composite conductor preform is 800°C~950°C; the time of the hot pressing treatment of the composite conductor preform is 20min~50min; and the pressure of the hot pressing treatment of the composite conductor preform is 200kN~1200kN.

[0034] In addition, a composite conductor is prepared by the above-mentioned method for preparing a composite conductor, wherein the composite conductor comprises:

[0035] Metal powder, wherein the metal powder is metal powder arranged in an orderly manner in a conductive direction under the driving force of an electric field; and

[0036] Graphene is filled between the orderly arranged metal powders, and the graphene covers the metal powders to form a graphene layer.

[0037] Optionally, in some embodiments of the present application, the material of the metal powder includes one or more of copper, silver, copper alloy, and silver alloy; the shape of the metal powder includes one or more of dendritic, rod-shaped, flaky, cubic, spherical, or nearly spherical; the average particle size of the metal powder is 10 μm to 100 μm; and the number of graphene layers is 3 to 8 layers.

[0038] In addition, a conductive element includes a composite conductor prepared by the above-mentioned method for preparing a composite conductor, or includes the above-mentioned composite conductor; the conductive element includes a wire or an electrical contact conductor.

[0039] Compared with the existing technology, the preparation method of the composite conductor provided in the present application is that the conductive slurry is subjected to the action of the electric field, and the metal powder acts as the conductive unit. The metal powders of different shapes have different position arrangements, resulting in different magnetic fields formed when they are conductive. The interaction between different magnetic fields causes the metal powders to move in position, forming an optimal conductive position distribution under the action of the magnetic field; after heat treatment, the resin can be carbonized and cracked to generate graphene on the surface of the metal powder, and a composite conductor with a continuous mixture of graphene and metal powder is obtained. Since the metal powders are arranged and distributed according to the optimal conductive position, the conductive performance of the composite conductor is significantly improved, and the continuously distributed graphene can further improve the hardness and anti-welding performance of the conductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0041] FIG1 is a flow chart of a method for preparing a composite conductor provided in an embodiment of the present application. Implementation Methods of the Application

[0042] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0043] The present application provides composite materials, optoelectronic devices, and methods for preparing the same. These are described in detail below. It should be noted that the order in which the following embodiments are described does not limit the preferred order of the embodiments. Furthermore, in the description of this application, the term "including" means "including but not limited to." Terms such as "first," "second," and "third" are used solely as designations and do not impose numerical requirements or establish a sequence.

[0044] In this application, "and / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0045] In this application, expressions such as "one or more" refer to one or more of the listed items, and "multiple" refers to any combination of two or more of these items, including any combination of single items or plural items. For example, "at least one of a, b or c" or "at least one of a, b and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc or abc, where a, b and c can be single or plural, respectively.

[0046] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in a range format is merely for convenience and brevity and should not be construed as a hard limit on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible subranges and single numbers within the range. For example, the description of the range from 0.04 to 0.1 should be considered to have specifically disclosed subranges such as from 0.04 to 0.05, from 0.05 to 0.06, from 0.06 to 0.07, from 0.07 to 0.09, etc., as well as single numbers within the range, such as 0.04, 0.05, and 0.06, regardless of the range. In addition, whenever a numerical range is indicated herein, it is intended to include any cited number (fractional or integer) within the indicated range.

[0047] In a first aspect, embodiments of the present application provide a composite conductor, comprising:

[0048] Metal powder, wherein the metal powder is metal powder arranged in an orderly manner in a conductive direction under the driving force of an electric field; and

[0049] Graphene is filled between the orderly arranged metal powders, and the graphene covers the metal powders to form a graphene layer.

[0050] It should be noted that orderly arrangement in the conductive direction means that when different metals have different grain orientations and different conductive properties, under the action of an electric field or a magnetic field, the metal powder will be arranged in the optimal conductive orientation. If this conductive orientation arrangement is well maintained, the conductivity of the composite conductor can be improved.

[0051] In the composite conductor provided in the present application, the metal powder is distributed in a position according to a preferred conductive direction, and the graphene is in close contact with the metal powder, so that the conductive performance of the composite conductor is significantly improved. The graphene can further enhance the hardness and anti-welding performance of the conductor.

[0052] In some embodiments, the material of the metal powder includes one or more of copper, silver, copper alloy, and silver alloy.

[0053] In some embodiments, the shape of the metal powder includes one or more of dendritic, rod-like, flake-like, cubic, spherical, or nearly spherical shapes.

[0054] In some embodiments, the average particle size of the metal powder is 10 μm to 100 μm, for example, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, etc.

[0055] In some embodiments, the number of graphene layers is 3 to 8 layers, for example, 4 layers, 5 layers, 6 layers, 7 layers, etc.

[0056] In some embodiments, the composite conductor further comprises a metal oxide, which can further enhance the anti-welding performance of the composite conductor.

[0057] In some embodiments, the metal oxide includes one or more of copper oxide and silver oxide.

[0058] In a second aspect, as shown in FIG1 , an embodiment of the present application provides a method for preparing a composite conductor, comprising:

[0059] S11. Providing a conductive paste, wherein the conductive paste includes metal powder and a reagent, wherein the reagent includes a resin and a polar compound;

[0060] S12, applying an electric field to the conductive slurry to obtain a composite conductor precursor;

[0061] S13, coating the composite conductor precursor with a graphene layer to obtain a composite conductor preform;

[0062] S14. Hot pressing the composite conductor preform to obtain a composite conductor.

[0063] The present application provides a method for preparing a composite conductor. Under the action of an electric field, a conductive paste uses metal powder as a conductive unit. Metal powders of different shapes have different position arrangements, resulting in different magnetic fields formed when conducting electricity. The interaction of different magnetic fields causes the metal powders to move in position, forming an optimal conductive position distribution under the action of the magnetic field. After heat treatment, the resin can be carbonized and cracked to generate graphene on the surface of the metal powder, thereby obtaining a composite conductor of a continuous mixture of graphene and metal powder. Since the metal powders are arranged and distributed according to the optimal conductive position, the conductive performance of the composite conductor is significantly improved, and the continuously distributed graphene can further enhance the hardness and anti-welding performance of the conductor.

[0064] In the S11:

[0065] In some embodiments, the mass fraction of the metal powder in the conductive paste is 40% to 60%, for example, 42%, 45%, 48%, 50%, 52%, 55%, 58%, etc. Within the mass fraction range, the dissolution of the metal powder is facilitated.

[0066] In some embodiments, the resin includes one or more of epoxy resin, acrylic resin, amino resin, alkyd resin, polyurethane resin, cyclic silicone resin, and fluorocarbon resin. As a binder, the resin has good compatibility with both organic and inorganic materials, promoting the dissolution and dispersion of metal powder in polar compounds. Furthermore, the resin is a high-molecular-weight organic polymer that can provide a carbon source for graphene growth.

[0067] In some embodiments, the polar compound includes one or more of methanol, ethanol, formamide, trifluoroacetic acid, DMSO, acetonitrile, DMF, hexamethylphosphoramide, acetic acid, propanol, pyridine, tetramethylethylenediamine, acetone, and triethylamine. Polar compounds have good electrical conductivity due to the misalignment of the centers of gravity of positive and negative charges within the molecule, which results in polarity. This allows for continuous conduction during electrical processing, promoting the movement of metal powder.

[0068] In some embodiments, the mass ratio of the resin to the polar compound is (10-30):(5-10), for example, it can be 15:8, 20:8, 25:8, etc.

[0069] In some embodiments, the reagent further includes a solvent, which is beneficial for improving the surface tension between the polar compound and the resin, and further promoting uniform dispersion of the metal powder in the slurry.

[0070] Furthermore, the solvent includes one or more of tetrahydrofuran, benzene, toluene, xylene, and n-butanol.

[0071] In some embodiments, the mass ratio of the resin to the solvent is (10-30): (15-35), for example, it can be 15:20, 15:25, 15:30, 20:20, 20:25, 20:30, 25:20, 25:30, etc.

[0072] In some embodiments, the reagent further includes an auxiliary carbon source, which can provide a carbon source for the growth of graphene and promote the growth of synthetic graphene on the surface of the metal powder.

[0073] Furthermore, the auxiliary carbon source includes one or more of phenanthrene, anthracene, naphthalene, and polymethyl methacrylate (PMMA).

[0074] In some embodiments, the mass ratio of the resin to the auxiliary carbon source is (10-30): (1-3), for example, it can be 12:2, 15:2, 18:2, 20:2, 22:2, 25:2, 28:2, etc.

[0075] In some embodiments, the reagent further includes a metal oxide. During the heat treatment, the metal oxide reacts with the long-chain carbon formed after the resin is carbonized, converting the long-chain carbon into short-chain carbon, which is then decomposed into carbon, thereby promoting the formation of graphene. A small amount of unreacted metal oxide may remain in the composite conductor, thereby improving the composite conductor's resistance to fusion welding.

[0076] Furthermore, the metal oxide includes one or more of copper oxide and silver oxide.

[0077] In some embodiments, the mass ratio of the resin to the metal oxide is (10-30):(0.1-10), for example, it can be 12:5, 15:5, 18:5, 20:5, 22:5, 25:5, 28:5, etc.

[0078] In some embodiments, the reagent further comprises a curing agent, which can chemically react with the epoxy resin to form a three-dimensional network polymer.

[0079] Furthermore, the curing agent includes one or more of an amine curing agent and an acid anhydride curing agent. The amine curing agent includes one or more of a polyamide curing agent, an aliphatic amine curing agent, an aromatic amine curing agent, an alicyclic amine curing agent, a polyetheramine curing agent, and an imidazole curing agent. The acid anhydride curing agent includes one or more of an aromatic anhydride curing agent, an aliphatic anhydride curing agent, and an alicyclic anhydride curing agent.

[0080] In some embodiments, the mass ratio of the resin to the curing agent is (10-30): (0.1-15), for example, it can be 12:5, 15:5, 18:5, 20:5, 22:5, 25:5, 28:5, etc.

[0081] It can be understood that, in the reagents, organic substances containing carbon can all be used as carbon sources for graphene growth, such as resins, solvents, and the like.

[0082] In said S12:

[0083] In some embodiments, the electric field has an electric field strength of 100 V / cm to 260 V / cm, for example, 120 V / cm, 150 V / cm, 180 V / cm, 200 V / cm, 220 V / cm, 250 V / cm, etc. Within this electric field strength range, the metal powders are advantageously induced to arrange sequentially along the conductive direction.

[0084] It can be understood that the power source of the electric field can be direct current or alternating current.

[0085] In some embodiments, the method of applying the electric field includes: allowing the conductive paste to flow through the electric field. It is understood that the fluidity of the conductive paste passing through the electric field can ensure that each metal powder is affected by the electric field force, further promoting the movement and sorting of the metal powder.

[0086] Specifically, a 3D printing method may be used to place the conductive paste in a 3D printing device, and an electric field is set at the outlet of the 3D printing device.

[0087] In some embodiments, the distance between the electric field and the outlet of the 3D printing device is 2 cm to 8 cm, for example, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, etc. Within this distance range, the outflow of the conductive paste is not affected and the metal powder in the conductive paste can be effectively arranged in an orderly manner along the conductive direction.

[0088] It can be understood that by using 3D printing, the orderly arranged metal powder can be solidified into a model, which is convenient for subsequent sintering processing.

[0089] In other embodiments, the method of applying the electric field includes providing a mold, placing the conductive paste in the mold, and applying the electric field to the mold. It is understood that applying the electric field directly to the mold can prevent leakage of the conductive paste during flow, and the mold is the desired shape, which greatly facilitates subsequent operations.

[0090] In some embodiments, the composite conductor precursor includes metal powders arranged in an orderly manner along a conductive direction, and a reagent doped in gaps between adjacent metal powders.

[0091] In said S13:

[0092] In some embodiments, coating the composite conductor precursor with a graphene layer includes: introducing a protective gas and performing a first heat treatment to obtain a carbide.

[0093] Furthermore, the temperature of the first heat treatment is 500°C~700°C, for example, it can be 520°C, 550°C, 580°C, 600°C, 620°C, 650°C, 680°C, etc.; the time of the first heat treatment is 20min~38min, for example, it can be 22min, 25min, 28min, 30min, 32min, 35min, etc.

[0094] In some embodiments, the first heat treatment is performed in a vacuum environment with a vacuum degree of 10 -3 kPa.

[0095] In some embodiments, the protective gas includes one or more of nitrogen, helium, argon, xenon, krypton, neon, and radon.

[0096] In this way, under the conditions of the first heat treatment, it is beneficial to promote the carbonization of the carbon source, generate short-chain carbides and crack into carbon.

[0097] In some embodiments, after obtaining the carbide, the method further includes: introducing an auxiliary gas and performing a second heat treatment to obtain a graphene layer.

[0098] Furthermore, the temperature of the second heat treatment is 800°C~1050°C, for example, it can be 850°C, 900°C, 950°C, 1000°C, etc.; the time of the second heat treatment is 20min~50min, for example, it can be 25min, 30min, 35min, 40min, 45min, etc.

[0099] In some embodiments, the auxiliary gas includes hydrogen. The hydrogen can promote the cracking of the carbon source, improving the uniformity and quality of graphene growth; hydrogen can etch the boundaries of the already grown graphene and its internal defects, thereby affecting the crystal domain size and morphology of the graphene.

[0100] In some embodiments, the gas flow rate of the auxiliary gas is 10 sccm~500 sccm, for example, it can be 50 sccm, 100 sccm, 150 sccm, 200 sccm, 250 sccm, 300 sccm, 350 sccm, 400 sccm, 450 sccm, etc.

[0101] It is understood that the second heat treatment can also be performed in a vacuum environment and in an atmosphere of protective gas.

[0102] Thus, under the conditions of the second heat treatment, it is favorable for short-chain carbides and carbon to be transformed into graphene.

[0103] It should be noted that the grown graphene directly fills the space occupied by the original reagent, which is beneficial to the continuity of the graphene and fully contacts the metal powder, thereby improving the conductivity, hardness and anti-welding performance of the composite conductor.

[0104] In said S14:

[0105] In some embodiments, the temperature of the extrusion treatment is 800°C~950°C, for example, it can be 820°C, 850°C, 880°C, 900°C, 920°C, etc.; the time of the extrusion treatment is 20min~50min, for example, it can be 25min, 30min, 35min, 40min, 45min, etc.; the pressure of the extrusion treatment is 200kN~1200kN, for example, it can be 200kN, 300kN, 400kN, 500kN, 600kN, 700kN, 800kN, 900kN, 1000kN, 1100kN, etc.

[0106] Under the above-mentioned extrusion treatment conditions, it is beneficial to remove the gaps in the composite conductor, make the connection between graphene and metal powder closer, and improve the conductivity of the composite conductor.

[0107] In a third aspect, an embodiment of the present application further provides a conductive element, comprising a composite conductor produced by the above-mentioned production method.

[0108] In some embodiments, the conductive element comprises a wire or an electrical contact conductor.

[0109] The present application will be described in detail below through specific examples. The following examples are only some examples of the present application and are not limitations of the present application.

[0110] Example 1

[0111] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0112] 55 g of copper powder with an average particle size of 50 μm, 30 g of epoxy resin, and 25 g of methanol were provided and mixed to obtain a conductive paste;

[0113] The conductive paste is placed in a printing device, and a direct current with an electric field strength of 200 V / cm is applied 5 cm from the printing outlet of the 3D printing device to induce the copper powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0114] The composite conductor precursor is placed in a vacuum of 10 -3 kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep it warm for 30 minutes to fully carbonize the resin to obtain short-chain carbides; raise the temperature to 1000 ° C again, introduce 200 sccm of hydrogen, and keep it warm for 30 minutes to convert the short-chain carbides into graphene with 5 layers; sintering and hot pressing are carried out at a temperature of 900 ° C, keep it warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0115] Example 2

[0116] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0117] 50 g of copper powder with an average particle size of 50 μm, 10 g of acrylic resin, 18 g of ethanol, 15 g of benzene, 2 g of phenanthrene, and 5 g of an amine curing agent were provided and mixed to obtain a conductive paste;

[0118] The conductive paste is placed in a printing device, and a direct current with an electric field strength of 200 V / cm is applied 5 cm from the printing outlet of the 3D printing device to induce the copper powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0119] The composite conductor precursor is placed in a vacuum of 10 -3kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep it warm for 30 minutes to fully carbonize the resin to obtain short-chain carbides; raise the temperature to 1000 ° C again, introduce 200 sccm of hydrogen, and keep it warm for 30 minutes to convert the short-chain carbides into graphene with 5 layers; sintering and hot pressing are carried out at a temperature of 900 ° C, keep it warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0120] Example 3

[0121] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0122] 40 g of copper powder with an average particle size of 50 μm, 20 g of acrylic resin, 15 g of ethanol, 15 g of tetrahydrofuran, 1 g of PMMA, 5 g of an amine curing agent, and 4 g of copper oxide were mixed to obtain a conductive paste;

[0123] The conductive paste is placed in a printing device, and a direct current with an electric field strength of 200 V / cm is applied 5 cm from the printing outlet of the 3D printing device to induce the copper powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0124] The composite conductor precursor is placed in a vacuum of 10 -3 kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep it warm for 30 minutes to fully carbonize the resin to obtain short-chain carbides; raise the temperature to 1000 ° C again, introduce 200 sccm of hydrogen, and keep it warm for 30 minutes to convert the short-chain carbides into graphene with 5 layers; sintering and hot pressing are carried out at a temperature of 900 ° C, keep it warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0125] Example 4

[0126] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0127] 40 g of copper powder with an average particle size of 50 μm, 30 g of epoxy resin, and 30 g of methanol were provided and mixed to obtain a conductive paste;

[0128] The conductive paste is placed in a printing device, and a direct current with an electric field strength of 100 V / cm is applied 5 cm from the printing outlet of the 3D printing device to induce the copper powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0129] The composite conductor precursor is placed in a vacuum of 10 -3kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep it warm for 30 minutes to fully carbonize the resin to obtain short-chain carbides; raise the temperature to 1000 ° C again, introduce 200 sccm of hydrogen, and keep it warm for 30 minutes to convert the short-chain carbides into graphene with 5 layers; sintering and hot pressing are carried out at a temperature of 900 ° C, keep it warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0130] Example 5

[0131] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0132] 40 g of copper powder with an average particle size of 50 μm, 30 g of epoxy resin, and 30 g of methanol were provided and mixed to obtain a conductive paste;

[0133] The conductive paste is placed in a printing device, and a direct current with an electric field strength of 260 V / cm is applied 5 cm from the printing outlet of the 3D printing device to induce the copper powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0134] The composite conductor precursor is placed in a vacuum of 10 -3 kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep it warm for 30 minutes to fully carbonize the resin to obtain short-chain carbides; raise the temperature to 1000 ° C again, introduce 200 sccm of hydrogen, and keep it warm for 30 minutes to convert the short-chain carbides into graphene with 5 layers; sintering and hot pressing are carried out at a temperature of 900 ° C, keep it warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0135] Example 6

[0136] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0137] 40 g of copper powder with an average particle size of 50 μm, 30 g of epoxy resin, and 30 g of methanol were provided and mixed to obtain a conductive paste;

[0138] The conductive paste is placed in a mold, and the mold is electrified with an electric field strength of 200 V / cm to induce the copper powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0139] The composite conductor precursor is placed in a vacuum of 10 -3kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep it warm for 30 minutes to fully carbonize the resin to obtain short-chain carbides; raise the temperature to 1000 ° C again, introduce 200 sccm of hydrogen, and keep it warm for 30 minutes to convert the short-chain carbides into graphene with 5 layers; sintering and hot pressing are carried out at a temperature of 900 ° C, keep it warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0140] Example 7

[0141] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0142] 40 g of copper powder with an average particle size of 50 μm, 30 g of epoxy resin, and 30 g of methanol were provided and mixed to obtain a conductive paste;

[0143] The conductive paste is placed in a printing device, and a direct current with an electric field strength of 200 V / cm is applied 5 cm from the printing outlet of the 3D printing device to induce the copper powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0144] The composite conductor precursor is placed in a vacuum of 10 -3 kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep warm for 30 minutes to fully carbonize the resin to obtain short-chain carbides; raise the temperature to 800 ° C again, introduce 200 sccm of hydrogen, and keep warm for 30 minutes to convert the short-chain carbides into graphene with 5 layers of graphene; sintering and hot pressing are carried out at a temperature of 900 ° C, keep warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0145] Example 8

[0146] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0147] 40 g of copper powder with an average particle size of 50 μm, 30 g of epoxy resin, and 30 g of methanol were provided and mixed to obtain a conductive paste;

[0148] The conductive paste is placed in a printing device, and a direct current with an electric field strength of 200 V / cm is applied 5 cm from the printing outlet of the 3D printing device to induce the copper powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0149] The composite conductor precursor is placed in a vacuum of 10 -3kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep warm for 30 minutes to fully carbonize the resin to obtain short-chain carbide; raise the temperature to 1050 ° C again, introduce 200 sccm of hydrogen, and keep warm for 30 minutes to convert the short-chain carbide into graphene with 5 layers of graphene; sintering and hot pressing are carried out at a temperature of 900 ° C, keep warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0150] Example 9

[0151] This embodiment provides a composite conductor, and the preparation method thereof is as follows:

[0152] 40 g of silver powder with an average particle size of 50 μm, 30 g of epoxy resin, and 30 g of methanol were provided and mixed to obtain a conductive paste;

[0153] The conductive paste is placed in a printing device, and a direct current with an electric field strength of 200 V / cm is applied 5 cm from the printing outlet of the 3D printing device to induce the silver powder in the conductive paste to move and arrange in a conductive direction to obtain a composite conductor precursor;

[0154] The composite conductor precursor is placed in a vacuum of 10 -3 kPa vacuum chamber, introduce helium and nitrogen as protective gases, raise the temperature to 600 ° C, and keep it warm for 30 minutes to fully carbonize the resin to obtain short-chain carbides; raise the temperature to 1000 ° C again, introduce 200 sccm of hydrogen, and keep it warm for 30 minutes to convert the short-chain carbides into graphene with 5 layers; sintering and hot pressing are carried out at a temperature of 900 ° C, keep it warm for 10 minutes, and a pressure of 500 kN to obtain a composite conductor.

[0155] Comparative Example 1

[0156] This comparative example provides a composite conductor, the preparation method of which is as follows:

[0157] 40 g of copper powder with an average particle size of 50 μm, 30 g of epoxy resin, and 30 g of methanol were provided and mixed to obtain a conductive paste;

[0158] The conductive slurry was heated to 1000° C., 200 sccm of hydrogen was introduced, and the temperature was kept constant for 30 minutes to convert the short-chain carbide into graphene with 5 layers, thereby obtaining a composite conductor.

[0159] Comparative Example 2

[0160] This comparative example provides a composite conductor, the preparation method of which is as follows:

[0161] Graphene is prepared on the surface of copper powder by vapor deposition method to obtain a composite conductor.

[0162] Comparative Example 3

[0163] This comparative example provides a composite conductor, the preparation method of which is as follows:

[0164] 40 g of silver powder with an average particle size of 50 μm, 30 g of epoxy resin, and 30 g of methanol were provided and mixed to obtain a conductive paste;

[0165] The conductive slurry was heated to 1000° C., 200 sccm of hydrogen was introduced, and the temperature was kept constant for 30 minutes to convert the short-chain carbide into graphene with 5 layers, thereby obtaining a composite conductor.

[0166] The thermal and electrical conductivities of the composite conductors of Examples 1-9 and Comparative Examples 1-3 were measured. The electrical conductivity test method was based on T / CSTM00591-2022, and the thermal conductivity test method was based on GB / T22588-2008. The results are shown in Table 1.

[0167] Table 1

[0168] Electrical conductivity %IACS Thermal conductivity W / (m•K) Example 1 105 415 Example 2 106 417 Example 3 104 419 Example 4 107 407 Example 5 109 408 Example 6 108 411 Example 7 110 413 Example 8 106 410 Example 9 111 480 Comparative Example 1 103 395 Comparative Example 2 104 392 Comparative Example 3 109 435

[0169] As can be seen from Table 1, the electrical conductivity and thermal conductivity of the composite conductors in Examples 1 to 9 are significantly improved compared with Comparative Examples 1 to 3, regardless of whether it is copper powder or silver powder. This is because after the electric field treatment, the metal powders are arranged in the conductive direction. When the composite conductor is used for conduction, the magnetic field inside the metal powders does not repel each other, which is beneficial to improving the conductivity of the composite conductor. In addition, in the metal powders arranged in an orderly manner in the conductive direction, the in-situ growth of graphene is beneficial to the close contact between the graphene and the metal powder, promoting the improvement of the conductivity and anti-welding properties of the metal powder by graphene, and effectively improving the performance of the composite conductor.

[0170] The composite conductor, preparation method, and conductive element provided in the embodiments of the present application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present application.

Claims

1. A method for preparing a composite conductor, wherein: include: Providing a conductive paste, wherein the conductive paste comprises metal powder and a reagent, wherein the reagent comprises a resin and a polar compound; Applying an electric field to the conductive paste to obtain a composite conductor precursor; Coating the composite conductor precursor with a graphene layer to obtain a composite conductor preform; The composite conductor preform is subjected to hot pressing treatment to obtain a composite conductor.

2. The method for preparing a composite conductor according to claim 1, wherein: The method of applying an electric field includes flowing the conductive paste through the electric field.

3. The method for preparing a composite conductor according to claim 2, wherein: The method for making the conductive paste flow through the electric field includes: placing the conductive paste in a 3D printing device, setting an electric field at the outlet of the 3D printing device; the distance between the electric field and the outlet of the 3D printing device is 2 cm to 8 cm.

4. The method for preparing a composite conductor according to claim 1, wherein: The method for applying an electric field comprises: providing a mold, placing the conductive paste in the mold, and applying an electric field to the mold.

5. The method for preparing a composite conductor according to claim 1, wherein: The electric field strength of the electric field is 100V / cm~260V / cm; and the power source of the electric field is direct current or alternating current.

6. The method for preparing a composite conductor according to claim 1, wherein: The material of the metal powder includes one or more of copper, silver, copper alloy, and silver alloy; the shape of the metal powder includes one or more of dendritic, rod-shaped, flaky, cubic, spherical or nearly spherical; and the average particle size is 10μm~100μm.

7. The method for preparing a composite conductor according to claim 1, wherein: The resin includes one or more of epoxy resin, acrylic resin, amino resin, alkyd resin, polyurethane resin, cyclic silicone resin, and fluorocarbon resin; and / or The polar compound includes one or more of methanol, ethanol, formamide, trifluoroacetic acid, DMSO, acetonitrile, DMF, hexamethylphosphoramide, acetic acid, propanol, pyridine, tetramethylethylenediamine, acetone, and triethylamine.

8. The method for preparing a composite conductor according to claim 1, wherein: In the conductive paste, the mass fraction of the metal powder is 40% to 60%; and / or The mass ratio of the resin to the polar compound is (10-30):(5-10).

9. The method for preparing a composite conductor according to claim 1, wherein: The reagent also includes a solvent; the solvent includes one or more of tetrahydrofuran, benzene, toluene, xylene, and n-butanol; the mass ratio of the resin to the solvent is (10-30): (15-35).

10. The method for preparing a composite conductor according to claim 1, wherein: The reagent also includes an auxiliary carbon source; the auxiliary carbon source includes one or more of phenanthrene, anthracene, naphthalene, and polymethyl methacrylate; the mass ratio of the resin to the auxiliary carbon source is (10-30): (1-3).

11. The method for preparing a composite conductor according to claim 1, wherein: The reagent also includes a metal oxide; the metal oxide includes one or more of copper oxide and silver oxide; the mass ratio of the resin to the metal oxide is (10-30): (0.1-10).

12. The method for preparing a composite conductor according to claim 1, wherein: The reagent also includes a curing agent; the curing agent includes one or more of an amine curing agent and an acid anhydride curing agent; the amine curing agent includes one or more of a polyamide curing agent, an aliphatic amine curing agent, an aromatic amine curing agent, an alicyclic amine curing agent, a polyether amine curing agent, and an imidazole curing agent; the acid anhydride curing agent includes one or more of an aromatic anhydride curing agent, an aliphatic anhydride curing agent, and an alicyclic anhydride curing agent; the mass ratio of the resin to the curing agent is (10~30):(0.1~15).

13. The method for preparing a composite conductor according to claim 1, wherein: The step of coating the composite conductor precursor with a graphene layer includes: introducing a protective gas and performing a first heat treatment to obtain a carbide.

14. The method for preparing a composite conductor according to claim 13, wherein: The temperature of the first heat treatment is 500° C. to 700° C.; the time of the first heat treatment is 20 min to 38 min; and / or The first heat treatment is performed in a vacuum environment, and the vacuum degree of the vacuum environment is 10 -3 kPa; and / or The protective gas includes one or more of nitrogen, helium, argon, xenon, krypton, neon and radon.

15. The method for preparing a composite conductor according to claim 13, wherein: After the carbide is obtained, the method further comprises: introducing an auxiliary gas and performing a second heat treatment to obtain a graphene layer.

16. The method for preparing a composite conductor according to claim 15, wherein: The temperature of the second heat treatment is 800°C to 1050°C; the time of the second heat treatment is 20min to 50min; and / or The auxiliary gas includes hydrogen; the gas flow rate of the auxiliary gas is 10 sccm to 500 sccm; and / or The number of graphene layers is 3 to 8.

17. The method for preparing a composite conductor according to claim 1, wherein: The temperature of the hot pressing treatment of the composite conductor preform is 800° C. to 950° C.; the time of the hot pressing treatment of the composite conductor preform is 20 min to 50 min; and the pressure of the hot pressing treatment of the composite conductor preform is 200 kN to 1200 kN.

18. A composite conductor, wherein: Prepared by the preparation method of the composite conductor according to any one of claims 1 to 17, the composite conductor comprises: Metal powder, wherein the metal powder is metal powder arranged in an orderly manner in a conductive direction under the driving force of an electric field; and Graphene, wherein the graphene is filled between the orderly arranged metal powders, and the graphene covers the metal powders to form a graphene layer.

19. The composite conductor of claim 18, wherein: The material of the metal powder includes one or more of copper, silver, copper alloy, and silver alloy; the shape of the metal powder includes one or more of dendritic, rod-shaped, flaky, cubic, spherical or nearly spherical; the average particle size of the metal powder is 10μm~100μm; the number of graphene layers is 3~8 layers.

20. A conductive element, wherein: It comprises a composite conductor prepared by the method for preparing a composite conductor according to any one of claims 1 to 17, or comprises a composite conductor according to any one of claims 18 to 19; the conductive element comprises a wire or an electrical contact conductor.

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