Electrical contact conductor and method for producing the same

Abstract

The application provides an electrical contact conductor and a preparation method thereof, wherein the preparation method comprises: pressing metal particles into a metal skeleton with a through hole; filling graphene into the through hole to form a preform structure; and performing extrusion stretching on the preform structure to form the electrical contact conductor. The application aims to solve the technical problems of graphene agglomeration and disordered distribution in the preparation process of the existing electrical contact conductor.

Description

Technical Field

[0001] This application relates to the field of electrical conductor technology, specifically to an electrical contact conductor and its preparation method. Background Technology

[0002] Graphene is a material with excellent gas barrier properties, high electrical conductivity, high thermal conductivity, high strength, high flexibility, and strong inertness. Therefore, it is widely used in electrical contact conductors to improve the conductivity or wear resistance of electrical contact conductors, replace the use of existing precious metals, or comprehensively improve conductivity and wear resistance while reducing manufacturing costs.

[0003] In existing technologies, the application of graphene in electrical contact conductors mainly includes two methods: electroplating and deposition. Electroplating involves mixing metal ions and graphene in the same plating solution, allowing the graphene and metal to co-mix and form on the surface of the electrical contact conductor. Deposition involves depositing a graphene layer onto the surface of metal powder using vapor deposition, and then hot-extruding the metal powder into an electrical contact conductor, resulting in a conductor containing graphene.

[0004] The electroplating process mainly needs to solve the following technical problems: First, how to uniformly disperse graphene in the plating solution to prevent graphene agglomeration; second, how to ensure that the graphene is orderly distributed and agglomerated when electroplating a graphene-metal mixture onto the surface of the product to be plated. Therefore, in the electroplating process for making electrical contact conductors, dispersants are used to prevent graphene agglomeration in the plating solution and ensure graphene dispersion. In the plating layer, the distribution of graphene in the plating layer is mainly controlled by controlling the concentration of graphene in the plating solution, controlling the electroplating process conditions, and selecting the synergistic combination of different dispersants to prevent agglomeration. However, even so, graphene still exhibits agglomeration, and it is impossible to control the orderly distribution of graphene at a certain concentration.

[0005] In the deposition process for electrical contact conductors, the graphene on the surface of the metal powder deforms along with the metal powder, causing the originally ordered graphene to become disordered. When the metal powder is extruded into an electrical contact conductor, certain pressure and temperature conditions must be met. This also causes some graphene to revert back to graphite under the influence of temperature and pressure, reducing the conductivity of the original metal.

[0006] In summary, the existing methods for preparing electrical contact conductors result in electrical contact conductors containing aggregated and disordered graphene. Summary of the Invention

[0007] This application proposes an electrical contact conductor and its preparation method, aiming to solve the technical problem of aggregated and disordered graphene distribution in the electrical contact conductor formed by existing methods. Another objective of this invention is to address the problem of poor conductivity caused by the alternating transfer of electrons between metallic graphene in the electrical contact conductor.

[0008] In a first aspect, this application proposes a method for preparing an electrical contact conductor, comprising: pressing metal particles into a metal skeleton with through holes; filling graphene into the through holes to form a prefabricated structure; and extruding and stretching the prefabricated structure to form the electrical contact conductor.

[0009] Optionally, filling the through-hole with graphene includes: filling the through-hole with graphene by CVD; or filling the through-hole with spherical graphene or graphene sheets.

[0010] Optionally, the extrusion and stretching of the prefabricated structure includes: heating the prefabricated structure to a preset temperature range; the preset temperature range is 600 degrees Celsius to 900 degrees Celsius; intermittent annealing, and extruding and stretching the prefabricated structure during the intermittent annealing process.

[0011] Optionally, the prefabricated structure includes a first surface and a second surface disposed opposite to each other in its width direction; the extrusion and stretching of the prefabricated structure includes: applying tensile force to the first surface and the second surface respectively, and applying pressure to the remaining surfaces of the prefabricated structure, so that the prefabricated structure is stretched in the width direction.

[0012] Optionally, the metal skeleton has at least two conductive layers stacked in its thickness direction; the at least two conductive layers include a first conductive layer and a second conductive layer; applying tensile force to the first surface and the second surface respectively includes: applying a first tensile force to the first surface located on the first conductive layer, and applying a second tensile force to the second surface located on the second conductive layer.

[0013] Optionally, the first conductive layer and the second conductive layer are two surface layers of the metal skeleton in its thickness direction.

[0014] Optionally, after the prefabricated structure is extruded and stretched, the extrusion and stretching deformation rate of the prefabricated structure is 3% to 8%.

[0015] Optionally, the particle size of the metal particles is 20 to 70 μm.

[0016] Optionally, the metal particles are at least one of copper particles, aluminum particles, silver particles, copper-silver alloy particles, iron particles, copper-tin alloy particles, nickel-silver alloy particles, or copper-nickel alloy particles.

[0017] Secondly, this application also proposes an electrical contact conductor comprising at least two conductive layers, wherein at least two metal layers and a graphene layer are sequentially disposed along the width direction of the conductive layers, and the graphene layer is disposed between two adjacent metal layers; the graphene layer between two adjacent conductive layers is staggered in the width direction.

[0018] Optionally, at least two of the conductive layers include an adjacent third conductive layer and a fourth conductive layer; the third conductive layer includes a first metal layer, a first graphene layer, and a second metal layer arranged sequentially along its width direction; the fourth conductive layer includes a third metal layer, a second graphene layer, and a fourth metal layer arranged sequentially along its width direction; the third metal layer or the fourth metal layer is superimposed on the first graphene layer, and the third metal layer or the fourth metal layer is respectively in contact with portions of the first metal layer and the second metal layer, and the second graphene layer is superimposed on the first metal layer and the second metal layer.

[0019] Optionally, in a cross-section perpendicular to the thickness direction of the electrical contact conductor, the electrical contact conductor has graphene layers extending along its length and graphene layers extending along its width that are connected to each other.

[0020] Optionally, in a projection plane perpendicular to the thickness direction of the electrical contact conductor, the extension direction of the graphene layer intersects the length direction of the electrical contact conductor.

[0021] Optionally, the extension direction of the graphene layer forms an angle with the length direction, and the angle gradually decreases from the two surfaces located in the length direction toward the electrical contact conductor.

[0022] Optionally, the graphene layer has a shape that is one or more of quadrilateral, pentagonal, hexagonal, and heptagonal in a cross-section perpendicular to the length or width direction of the electrical contact conductor.

[0023] Optionally, the graphene layer has a width of 10-70 μm and a thickness of 1-10 μm.

[0024] Optionally, the ratio of the width of the graphene layer to the width of any adjacent metal layer is 1:6 to 1:1.5.

[0025] Unlike existing processes that use a mixture of graphene and metal to form a hybrid conductor, the preparation method proposed in this application fills the through-holes of a metal framework pre-pressed from metal particles with graphene. This allows the metal framework to provide support, fixation, and shaping for the graphene. During the extrusion and stretching process of the pre-fabricated structure, the metal framework clamps and fixes the graphene, achieving a densification effect. This ensures that the graphene layer density within the through-holes of the metal framework reaches a certain requirement. Simultaneously, it allows for mechanical exfoliation of the graphene layer, resulting in a highly ordered arrangement and a near-agglomerated state. Therefore, after the electrical contact conductor formed by the preparation method of this application becomes conductive, because the graphene and metal layers are separate conductive components, electrons can migrate independently within the graphene layer. This increases the rate of electron transfer between graphene layers and reduces the proportion of electron transfer through channels formed between or within the metal and graphene layers, thereby fully utilizing the conductivity of the graphene material. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic flowchart of the method for preparing an electrical contact conductor provided in an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of a prefabricated structure provided in an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of the stress state of the prefabricated structure under extrusion and tension provided in the embodiments of this application;

[0030] Figure 4 This is a schematic diagram of the structure of an electrical contact conductor provided in an embodiment of this application;

[0031] Figure 5 This is a schematic diagram of the cross-sectional structure of an electrical contact conductor provided in an embodiment of this application, perpendicular to its length.

[0032] Figure 6 This is a schematic diagram of the cross-sectional structure of another electrical contact conductor provided in the embodiments of this application, perpendicular to the length direction;

[0033] Figure 7 This is a schematic diagram of the projection of an electrical contact conductor provided in an embodiment of this application, perpendicular to the thickness direction;

[0034] Figure 8 This is a schematic diagram of another prefabricated structure provided in the embodiments of this application;

[0035] Figure 9 This is a planar schematic diagram of another electrical contact conductor provided in the embodiments of this application.

[0036] List of reference numerals

[0037]

[0038] Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0041] In this application, the term "exemplary" is used to mean "serving as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0042] In existing electrical contact conductor fabrication processes, graphene and metal are randomly mixed to form a hybrid conductor. When this hybrid conductor conducts electricity, electrons are transferred through the metal to the graphene and then back to the metal, resulting in frequent switching of electron channels between the metal and graphene. Although graphene replaces some of the metal as an electron migration channel, enabling rapid electron migration, under current processing and manufacturing conditions, graphene is prone to agglomeration and disordered arrangement. This leads to a disordered distribution of graphene in the hybrid conductor, and the proportion of electron migration between the metal and graphene in the overall electrical contact conductor is not high. Consequently, actual electron migration in the electrical contact conductor relies primarily on metal-to-metal interactions. Therefore, even with the addition of graphene, its superior conductivity and wear resistance are difficult to fully utilize.

[0043] To overcome the shortcomings of the prior art, this application proposes a method for preparing an electrical contact conductor. This method involves forming a continuous, dense, and orderly arranged graphene conductor layer within the electrical contact conductor. When the electrical contact conductor conducts electricity, the proportion of electrons transported solely through channels formed by the graphene is increased, while the proportion of electrons transported through channels formed between the metal and graphene or on the metal is reduced.

[0044] Please refer to Figures 1 to 9 As shown, Figure 1 This is a schematic flowchart of the method for preparing an electrical contact conductor provided in an embodiment of this application; Figure 2 This is a schematic diagram of a prefabricated structure provided in an embodiment of this application; Figure 3 This is a schematic diagram of the stress state of the prefabricated structure under extrusion and tension provided in the embodiments of this application; Figure 4 This is a schematic diagram of the structure of an electrical contact conductor provided in an embodiment of this application; Figure 5 This is a schematic diagram of the cross-sectional structure of an electrical contact conductor provided in an embodiment of this application, perpendicular to its length. Figure 6 This is a schematic diagram of the cross-sectional structure of another electrical contact conductor provided in the embodiments of this application, perpendicular to the length direction; Figure 7 This is a schematic diagram of the projection of an electrical contact conductor provided in an embodiment of this application, perpendicular to the thickness direction; Figure 8 This is a schematic diagram of another prefabricated structure provided in the embodiments of this application; Figure 9 This is a schematic diagram of the structure of another electrical contact conductor provided in the embodiments of this application.

[0045] Firstly, please refer to Figure 1 As shown in the embodiment of this application, a method for preparing an electrical contact conductor is proposed, comprising:

[0046] S01, pressing metal particles into a metal skeleton with through holes;

[0047] S02, graphene is filled into the through-holes to form a prefabricated structure;

[0048] S03, the prefabricated structure is extruded and stretched to form the electrical contact conductor.

[0049] Unlike existing processes that use a mixture of graphene and metal to form a hybrid conductor, the preparation method proposed in this application involves filling graphene into the through-holes of a metal framework pre-pressed from metal particles. This allows the metal framework to provide support, fixation, and shaping for the graphene. During the extrusion and stretching process of the prefabricated structure, the metal framework can clamp and fix the graphene, achieving a densification effect. This ensures that the density of the graphene layer 30 within the through-holes of the metal framework meets certain requirements. Simultaneously, it allows for mechanical exfoliation of the graphene layer 30, resulting in a highly ordered arrangement and a near-agglomerated state. Therefore, after the electrical contact conductor formed by the preparation method of this application becomes conductive, because the graphene layer 30 and the metal layer 20 are separate conductive components, electrons can migrate independently within the graphene layer 30. This increases the rate of electron transfer between graphene layers 30 and reduces the proportion of electron transfer through channels formed between the metal and graphene layers or on the metal, thereby fully utilizing the conductivity of the graphene material.

[0050] It should be noted that in step S01, the metal particles are first placed in an extrusion die, and a metal skeleton containing through holes is formed by hot extrusion. This metal skeleton contains several through holes. During implementation, the extrusion die can be designed according to the structural design requirements of the electrical contact conductor, so that the through holes in the formed metal skeleton have a preset size and are arranged in a preset order.

[0051] It should be noted that in step S02, graphene can be filled into the through-holes using a CVD method to form a prefabricated structure. The prefabricated structure is as follows: Figure 2As shown in Figure 8. CVD, or Chemical Deposition Method, involves filling through-holes with graphene using CVD. This ensures a relatively orderly distribution of graphene within the through-holes before extrusion and stretching. After extrusion and stretching, the CVD-deposited, orderly distributed graphene undergoes densification and further mechanical exfoliation. This process further mechanically exfoliates and orderly distributes the graphene that was randomly arranged during CVD and agglomerated during the extrusion process, improving the conductivity of the electrical contact conductor.

[0052] In some embodiments, spherical graphene or graphene sheets can also be filled into the through-holes. Compared to the CVD method, this method results in a more disordered distribution and greater agglomeration of graphene within the through-holes before extrusion and stretching, thus requiring stricter control of process parameters during extrusion and stretching. Generally, using the CVD method to fill graphene into the through-holes better ensures an orderly distribution and prevents agglomeration of graphene within the through-holes.

[0053] It should be noted that in step S03, the prefabricated structure is extruded and stretched in an extrusion stretching die. During extrusion, the metal skeleton exerts a certain compressive force on the graphene. Since the graphene fills the through-holes, the metal skeleton can stabilize the cross-sectional shape of the graphene layer 30. In the formed electrical contact conductor, the metal part can avoid the adverse effects of external forces on the graphene layer 30 during use. For example, during use, external forces are unlikely to cause deformation of the graphene layer 30.

[0054] Specifically, the prefabricated structure is placed in an extrusion and stretching mold; the prefabricated structure is heated to a preset temperature range, which is 600 degrees Celsius to 900 degrees Celsius. Intermittent annealing is then performed, during which the prefabricated structure is extruded and stretched. The extrusion and stretching deformation of the prefabricated structure is carried out under intermittent annealing conditions. Generally, when graphene fills the through-holes, some graphene layers do not establish connections. Simultaneously, because the prefabricated structure forms multiple conductive layers 10 stacked along the thickness direction, the thickness and number of layers of the resulting electrical contact conductor decrease due to extrusion and stretching deformation. Without annealing, graphene breaks, leading to reduced mechanical properties. Therefore, intermittent annealing helps to ensure the orderly arrangement of the graphene layers 30 and disperses agglomerated graphene. It also connects broken and unconnected graphene layers, forming a coherent and orderly arranged graphene, resulting in an orderly and non-agglomerated electrical contact conductor.

[0055] In some embodiments, for example, the prefabricated structure is heated to 900 degrees Celsius and then subjected to extrusion and stretching deformation with a deformation rate of 1%. After deformation, the temperature is lowered to 800 degrees Celsius, and the prefabricated structure is subjected to extrusion and stretching deformation again with a deformation rate of 2%. The temperature is gradually reduced until the deformation rate reaches the designed deformation rate to form an electrical contact conductor. Through extrusion and stretching deformation at different temperatures, graphene is mechanically exfoliated multiple times, resulting in its orderly arrangement and aggregation. Simultaneously, the connection stress between the metal and graphene is made uniform and without abrupt changes, which is beneficial for improving the mechanical properties, conductivity, and wear resistance of the electrical contact conductor.

[0056] It should be noted that the metal particles are at least one of copper particles, aluminum particles, silver particles, copper-silver alloy particles, iron particles, copper-tin alloy particles, nickel-silver alloy particles, or copper-nickel alloy particles. Of course, in some specific fields, the metal particles can also be selected from other conductive metals, which will not be listed here. Because copper has good electrical conductivity and ductility, the metal particles are generally selected from copper particles or copper-nickel alloy particles. In some embodiments, the particle size of the metal particles is 20-70 μm.

[0057] As an optional embodiment of the above embodiments, the prefabricated structure includes a first surface and a second surface disposed opposite to each other in its width direction. The first surface and the second surface are two end faces of the prefabricated structure located in the width direction. (Refer to...) Figure 2 As shown in Figure 8, the width direction and the axial direction of the through hole intersect each other. Typically, the through hole extends along a straight line, with the width direction and the axial direction of the through hole perpendicular to each other. In other embodiments, the through hole extends along a curve, such as an S-curve, in which case the width direction and the axial direction of the through hole intersect each other.

[0058] like Figure 3As shown, the extrusion stretching of the prefabricated structure includes: applying tensile forces F11 and F12 to the first and second surfaces respectively, and applying compressive forces F32, F31, F21, and F22 to the remaining surfaces of the prefabricated structure, thereby stretching the prefabricated structure in the width direction. For example, the first and second surfaces can be curved or planar. Typically, both the first and second surfaces are planar. The surfaces of the prefabricated structure other than the first and second surfaces are the remaining surfaces. By applying compressive forces to the remaining surfaces of the prefabricated structure, i.e., applying confining pressure to the prefabricated structure, the prefabricated structure is stretched only along the width direction when tensile forces are applied to the first and second surfaces, while being compressed in other directions, to form an electrical contact conductor. Applying tensile forces to stretch the prefabricated structure on two opposing surfaces in the width direction can effectively allow the graphene layer 30 to be mechanically exfoliated. By applying tensile forces only in the width direction and compressive forces in other directions, the formed graphene layer 30 is surrounded by compressive forces, which can prevent external forces from causing adverse deformation of the graphene layer 30.

[0059] like Figure 3 As shown, taking a cuboid prefabricated structure as an example, further explanation is provided: In some specific implementations, the prefabricated structure includes a third and a fourth surface arranged opposite each other in the length direction. The third and fourth surfaces are the two end faces of the prefabricated structure in the length direction. The prefabricated structure also includes a fifth and a sixth surface arranged opposite each other in the thickness direction. The fifth and sixth surfaces are the two end faces of the prefabricated structure in the thickness direction. The length direction, the width direction, and the thickness direction are mutually perpendicular. The axial direction of the through hole has a component in the length direction. Generally, the axial direction of the through hole is parallel to the length direction. The extrusion and stretching of the prefabricated structure is as follows: tensile forces F11 and F12 are applied to the first and second surfaces, first pressures F32 and F31 are applied to the third and fourth surfaces, and second pressures F21 and F22 are applied to the fifth and sixth surfaces, causing the prefabricated structure to be stretched in the width direction. Generally, in order to make the deformation of the prefabricated structure uniform in the non-stretching direction, the first pressures F32 and F31 are equal, and the second pressures F21 and F22 are equal.

[0060] Of course, in other embodiments, the prefabricated structure can be a non-cubic structure, such as a cylindrical structure, a prism structure, etc.

[0061] As an optional implementation of the above embodiments, combined with Figure 2As shown, the metal skeleton has at least two conductive layers 10 stacked in the thickness direction; the at least two conductive layers 10 include a first conductive layer 11 and a second conductive layer 12; the tensile force applied to the first surface and the second surface is as follows: a first tensile force F11 is applied to the first surface located on the first conductive layer 11, and a second tensile force F12 is applied to the second surface located on the second conductive layer 12. That is, the tensile forces applied in the width direction are not collinear, i.e., "misaligned" stretching, which allows the graphene layer 30 to deform and displace, which facilitates the mechanical exfoliation of graphene, reduces the degree of agglomeration, and facilitates the support of the metal layer 20 for the adjacent graphene layer 30, ensuring the stability of the graphene layer 30.

[0062] As an optional implementation of the above embodiments, the first conductive layer 11 and the second conductive layer 12 are two surface layers of the metal skeleton in the thickness direction. That is, during extrusion and stretching, the applied tensile force is located on the uppermost and lowermost conductive layers 10, respectively, which facilitates the "misaligned" stretching of the prefabricated structure, so that in the projection plane perpendicular to the thickness direction of the electrical contact conductor, the extension direction of the graphene layer 30 intersects the length direction of the electrical contact conductor, such as... Figure 4 As shown, the projection plane is the electron transport surface of the electrical contact conductor, and the orientation of the graphene layer 30 is the actual electron transport direction. The intersecting extension direction and length direction of the graphene layer 30 allows electrons to travel a longer distance within the graphene layer 30, which helps to increase the electron migration rate and the proportion of electrons migrating within the graphene layer 30. At the same time, this staggered stretching allows the graphene layer 30 to bend and extend within the projection plane, enabling mechanical peeling, improving its ordered arrangement, and reducing its agglomeration.

[0063] In some cases, the extension direction of the graphene layer forms an angle with the length direction, and the angle gradually decreases from the two surfaces located in the length direction towards the interior of the electrical contact conductor. Specifically, before the electrical contact conductor is stretched or compressed, the graphene layer 30 extends along the axis O2 of the through-hole; after the electrical contact conductor is stretched or compressed, the extension direction of the graphene layer 30 bends and extends along the bending center line O1. After stretching and compression, the extension direction of the graphene layer forms an angle with the length direction, i.e., the axis O2 and the bending center line O1 intersect each other. This angle gradually decreases from the two surfaces located in the length direction towards the interior of the electrical contact conductor. In some embodiments, this angle is smallest at the midpoint of the graphene layer 30. In some embodiments, the midpoint is formed by the intersection of the curved midline O1 of the graphene layer 30 and its length axis, which is the extension line of the graphene layer 30 (the axis O2 of the through hole) before the electrical contact conductor is stretched and compressed; that is, the included angle gradually increases from the intersection point towards the surfaces on both sides of the length direction. Figure 7 As shown, this graphene layer 30 exhibits a certain degree of bending compared to its unstretched state, which is beneficial for improving the mechanical properties of the graphene layer 30 and for its orderly arrangement, preventing agglomeration.

[0064] As an optional implementation of the above embodiments, after the prefabricated structure is extruded and stretched, the extrusion and stretching deformation rate of the prefabricated structure is 3% to 8%. The extrusion deformation rate can be calculated by the dimensional change rate in the width direction. For example, if the width dimension of the prefabricated structure is L0 and the width dimension of the formed electrical contact conductor is L1, then the extrusion and stretching deformation rate ε is:

[0065] ε=(L1-L0) / L1

[0066] Through research by the inventors of this invention, it was found that the extrusion deformation rate of the prefabricated structure is 3% to 8%, and the graphene layer 30 has a higher degree of ordered arrangement and is closer to a non-agglomerated state, which makes the mechanical properties, conductivity and wear resistance of the electrical contact conductor better.

[0067] As an optional implementation of the above embodiments, before pressing the metal particles into a metal framework with through holes, the preparation method further includes depositing a graphene layer on the surface of the metal particles. After pressing the metal particles into a metal framework, a graphene layer is formed inside the metal framework. Due to the agglomeration of graphene on the surface of the metal particles caused by pressing, subsequent stretching and extrusion will re-stretch the agglomerated graphene inside the metal framework to redistribute it in an orderly manner and reform the graphene layer, which helps to improve the conductivity and wear resistance of the electrical contact conductor. Generally, the graphene layer can be deposited on the surface of the metal particles by CVD.

[0068] Secondly, based on part or all of the methods for preparing electrical contact conductors proposed in the above embodiments, such as... Figure 4 As shown in the embodiments of this application, an electrical contact conductor is also proposed, comprising at least two conductive layers 10, wherein at least two metal layers 20 and graphene layers 30 are sequentially disposed along the width direction of each conductive layer 10; the graphene layers 30 between two adjacent conductive layers 10 are staggered in the width direction and are not in contact with each other. That is, the graphene layers 30 of two conductive layers 10 with adjacent thicknesses are not in contact with each other.

[0069] Compared to the graphene-metal hybrid structure in electrical contact conductors, the electrical contact conductor in this embodiment includes at least two conductive layers. Each conductive layer contains at least two metal layers 20 and graphene layers 30 sequentially disposed along its width direction. The graphene layers 30 between adjacent conductive layers 10 are staggered in the width direction and do not connect with each other. Adjacent metal layers 20 and graphene layers 30 are individual conductive portions, allowing electrons to migrate independently within the graphene layers 30. This increases the rate of electron transfer between graphene layers 30 and reduces the proportion of electron transfer through channels formed between metal-graphene layers or on the metal, thereby fully utilizing the conductivity of the graphene material.

[0070] Meanwhile, since the electrical contact conductor is formed through stretching and extrusion, the metal layer 20 and the graphene layer 30 are tightly connected, allowing the metal layer 20 to provide support, fixation, and shaping for the graphene. During the extrusion and stretching process of the prefabricated structure, the metal layer 20 can fix and clamp the graphene to achieve densification, ensuring that the density of the graphene layer 30 reaches a certain requirement within the through-holes of the metal framework. Simultaneously, it can mechanically peel off the graphene layer 30, resulting in a highly ordered arrangement of the graphene layer 30 and a near-agglomerated state, thus improving its electrical conductivity and mechanical properties.

[0071] Specifically, such as Figure 5 As shown in Figure 6, the electrical contact conductor comprises at least two conductive layers 10 stacked in its thickness direction; each conductive layer 10 has the graphene layer 30; and electron transfer is achieved through adjacent metal layers. Specifically, the graphene layer 30 is surrounded by adjacent metal layers 20 on the same layer and by metal layers 20 on adjacent conductive layers 10, such that the metal layers 20 provide strong support, protection, and shaping for the graphene layer 30. The graphene layer 30 is disposed between adjacent metal layers 20, and the graphene layer 30 and the two adjacent metal layers 20 are tightly connected after stretching and compression.

[0072] It should be noted that, in this embodiment, the metal layer 20 is a metal skeleton formed by metal particles in a mold. This metal skeleton contains through-holes. Graphene is filled into these through-holes to form a prefabricated structure. The prefabricated structure is then placed into an extrusion and stretching mold for extrusion and stretching, so that the graphene layer 30 is tightly connected to the two adjacent metal layers 20.

[0073] It should be noted that the metal layer 20 and the graphene layer 30 are arranged alternately along the width direction. For example, metal layer 20-graphene layer 30-metal layer 20-graphene layer 30-...-metal layer 20.

[0074] Typically, the width ratio of the graphene layer 30 to any adjacent metal layer 20 is between 1:6 and 1:1.5. This ratio is primarily designed to ensure that the metal layer 20 provides strong support for the graphene layer 30, guaranteeing an orderly and stable distribution of the graphene layer 30 within the formed electrical contact conductor and preventing deformation of the graphene layer 30 due to external forces. In some embodiments, the width of the graphene layer 30 is 10-70 μm, and the thickness of the graphene layer 30 is 1-10 μm.

[0075] Furthermore, as an optional implementation of the above embodiments, such as Figure 5 As shown, at least two of the conductive layers 10 include an adjacent third conductive layer 13 and a fourth conductive layer 14; the third conductive layer 13 includes a first metal layer 21, a first graphene layer 31 and a second metal layer 22 arranged sequentially along the width direction; the fourth conductive layer 14 includes a third metal layer 23, a second graphene layer 32 and a fourth metal layer 24 arranged sequentially along the width direction; the third metal layer 23 or the fourth metal layer 24 is superimposed on the first graphene layer 31, and the third metal layer 23 or the fourth metal layer 24 is respectively connected to a portion of the first metal layer 21 and a portion of the second metal layer 22, and the second graphene layer 32 is disposed on the first metal layer 21 and the second metal layer 22 superimposed on it. That is, the first graphene layer 31 and the second graphene layer 32 are not connected; the first graphene layer 31 is supported by the first metal layer 21, the second metal layer 22 and one of the third metal layer 23 or the fourth metal layer 24; the second graphene layer 32 is supported by the third metal layer 23, the fourth metal layer 24 and one of the first metal layer 21 or the second metal layer 22.

[0076] As an optional implementation of the above embodiments, such as Figure 9As shown, in a projection plane perpendicular to the thickness direction of the electrical contact conductor, and in a cross-section perpendicular to the thickness direction of the electrical contact conductor, the graphene layers extending along the length direction and the graphene layers extending along the width direction of the electrical contact conductor are connected to each other. It should be noted that the graphene layer extending along the length direction can be understood as having its two ends located on the third and fourth surfaces of the electrical contact conductor, respectively, along the length direction; or the graphene layer's extension direction has a component in the length direction. The graphene layer extending along the width direction can be understood as having its two ends located on the first and second surfaces of the electrical contact conductor, respectively, along the length direction; or the graphene layer's extension direction has a component in the width direction. For example, one graphene layer 30 extends approximately along the length direction, and another graphene layer 30 extends approximately along the width direction. During electron transport, electrons are transferred along the graphene layer 30, which extends approximately along its length, and eventually converge onto the graphene layer 30, which extends approximately along its width, completing the electron transfer and migration. The electrical contact conductor of this structure is for... Figure 8 The prefabricated structure is formed by extrusion and stretching.

[0077] In some embodiments, for the same conductive layer 10, there are multiple graphene layers 30 extending generally along the length direction, and they do not intersect each other. There are also multiple graphene layers 30 extending generally along the width direction, and they do not intersect each other. Each graphene layer 30 extending generally along the length direction intersects with a graphene layer 30 extending generally along the width direction. In this structure, the electrical contact conductor has crisscrossing graphene layers 30, improving electron mobility.

[0078] It should be noted that the graphene layer 30 extending approximately along the length direction is understood as follows: the electrical contact conductor has a third surface and a fourth surface arranged opposite to each other in the length direction, and the graphene layer 30 extends from the third surface to the fourth surface, its actual orientation being either a straight line or a curve. Similarly, the graphene layer 30 extending approximately along the width direction is understood as follows: the electrical contact conductor has a first surface and a second surface arranged opposite to each other in the width direction, and the graphene layer 30 extends from the first surface to the second surface, its actual orientation being either a straight line or a curve.

[0079] As an optional implementation of the above embodiments, such as Figure 4As shown in Figure 7, the extension direction of the graphene layer 30 intersects with its length direction. That is, the extension direction of the graphene layer 30 has a component in the length direction, or the graphene layer 30 extends in a curved manner rather than a straight line. In this structure, electrons can travel longer distances within the graphene layer 30, which helps to increase the electron migration rate and the ratio of electrons migrating within the graphene layer 30. Simultaneously, this misaligned stretching allows the graphene layer 30 to bend within the projection plane, enabling mechanical peeling, increasing its ordered arrangement, and reducing agglomeration.

[0080] As an optional implementation of the above embodiments, the extension direction of the graphene layer forms an angle with the length direction, and the angle gradually decreases from the two surfaces located in the length direction towards the interior of the electrical contact conductor. Specifically, before the electrical contact conductor is stretched or compressed, the graphene layer 30 extends along the axis O2 of the through-hole; after the electrical contact conductor is stretched or compressed, the extension direction of the graphene layer 30 bends and extends along the bending center line O1. After stretching and compression, the extension direction of the graphene layer forms an angle with the length direction, i.e., the axis O2 and the bending center line O1 intersect each other. This angle gradually decreases from the two surfaces located in the length direction towards the interior of the electrical contact conductor. In some embodiments, this angle is smallest at the midpoint of the graphene layer 30. In some embodiments, the midpoint is formed by the intersection of the curved midline O1 of the graphene layer 30 and its length axis, which is the extension line of the graphene layer 30 (the axis O2 of the through hole) before the electrical contact conductor is stretched and compressed; that is, the included angle gradually increases from the intersection point towards the surfaces on both sides of the length direction. Optionally, as... Figure 5 As shown in Figure 6, the graphene layer 30 has a shape that is one or more of quadrilateral, pentagonal, hexagonal, and heptagonal in a cross-section perpendicular to the length or width direction of the electrical contact conductor. The cross-sectional shape of the graphene layer 30 is determined by the shape of the through-holes in the metal framework. In some embodiments, the graphene layer 30 can have various shapes, such as a tetrahedron in the first conductive layer 11 and a pentagon in the second conductive layer 12. Of course, in some implementations, the graphene layer 30 can also have other shapes in the projection plane perpendicular to the length or width direction, which will be described in detail here.

[0081] In the above embodiments, the width, length, and thickness directions are relative orientations used to facilitate the full application of the technical concept of this application. In actual structures, implementers can redefine them.

[0082] The above provides a detailed description of an electrical contact conductor and its preparation method provided by the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing an electrical contact conductor, characterized in that, include: Metal particles are pressed into a metal skeleton with through holes; Graphene is filled into the through-holes to form a prefabricated structure; The prefabricated structure is extruded and stretched to form the electrical contact conductor; The extrusion and stretching of the prefabricated structure includes: The prefabricated structure is heated to a preset temperature range; Intermittent annealing is performed, and the prefabricated structure is extruded and stretched during the intermittent annealing process.

2. The preparation method according to claim 1, characterized in that, The step of filling the through-hole with graphene includes: filling the through-hole with graphene by CVD; or filling the through-hole with spherical graphene or graphene sheets.

3. The preparation method according to claim 1, characterized in that, The preset temperature range is 600 degrees Celsius to 900 degrees Celsius.

4. The preparation method according to claim 1, characterized in that, The prefabricated structure includes a first surface and a second surface disposed opposite to each other in its width direction; The extrusion and stretching of the prefabricated structure includes: Tensile forces are applied to the first and second surfaces respectively, and compressive forces are applied to the remaining surfaces of the prefabricated structure, causing the prefabricated structure to be stretched in the width direction.

5. The preparation method according to claim 4, characterized in that, The metal frame has at least two conductive layers stacked in its thickness direction; At least two of the conductive layers include a first conductive layer and a second conductive layer; The application of tensile force on the first surface and the second surface respectively includes: applying a first tensile force on the first surface located on the first conductive layer, and applying a second tensile force on the second surface located on the second conductive layer.

6. The preparation method according to claim 5, characterized in that, The first conductive layer and the second conductive layer are two surface layers of the metal skeleton in its thickness direction.

7. The preparation method according to claim 1, characterized in that, After the prefabricated structure is subjected to extrusion and stretching, the extrusion and stretching deformation rate of the prefabricated structure is 3%~8%.

8. The preparation method according to claim 1, characterized in that, The particle size of the metal particles is 20 to 70 μm.

9. The preparation method according to claim 1 or 8, characterized in that, The metal particles are at least one of copper particles, aluminum particles, silver particles, copper-silver alloy particles, iron particles, copper-tin alloy particles, or nickel-silver alloy particles.

10. The preparation method according to claim 1, characterized in that, Before pressing the metal particles into a metal framework with through holes, the preparation method further includes depositing a graphene layer on the surface of the metal particles.

11. An electrical contact conductor, characterized in that, It includes at least two conductive layers, each of which has at least two metal layers and a graphene layer disposed sequentially along its width direction, the graphene layer being disposed between two adjacent metal layers; the graphene layers between two adjacent conductive layers are staggered in the width direction and are not in contact with each other.

12. The electrical contact conductor as claimed in claim 11, characterized in that; At least two of the conductive layers include an adjacent third conductive layer and a fourth conductive layer; The third conductive layer includes a first metal layer, a first graphene layer, and a second metal layer arranged sequentially along its width direction. The fourth conductive layer includes a third metal layer, a second graphene layer, and a fourth metal layer arranged sequentially along its width direction; The third metal layer or the fourth metal layer is superimposed on the first graphene layer, and the third metal layer or the fourth metal layer is respectively connected to a portion of the first metal layer and a portion of the second metal layer. The second graphene layer is superimposed on the first metal layer and the second metal layer.

13. The electrical contact conductor as claimed in claim 11, characterized in that, In a cross-section perpendicular to the thickness direction of the electrical contact conductor, the electrical contact conductor has graphene layers extending along its length and graphene layers extending along its width that are connected to each other.

14. The electrical contact conductor as claimed in claim 11, characterized in that, In a projection plane perpendicular to the thickness direction of the electrical contact conductor, the extension direction of the graphene layer intersects the length direction of the electrical contact conductor.

15. The electrical contact conductor as claimed in claim 14, characterized in that, The graphene layer extends at an angle to the length direction, and the angle gradually decreases from the two surfaces located in the length direction toward the electrical contact conductor.

16. The electrical contact conductor according to any one of claims 11 to 15, characterized in that, The graphene layer has one or more shapes, including quadrilateral, pentagonal, hexagonal, and heptagonal, in a cross-section perpendicular to the length or width direction of the electrical contact conductor.

17. The electrical contact conductor as claimed in claim 11, characterized in that, The graphene layer has a width of 10-70 μm and a thickness of 1-10 μm.

18. The electrical contact conductor as claimed in claim 11 or 17, characterized in that, The ratio of the width of the graphene layer to the width of any adjacent metal layer is 1:6 to 1:1.5.

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