End processing method of aluminum conductive part and aluminum conductive part

Abstract

The invention discloses an end processing method of an aluminum conductive part and the aluminum conductive part. The end processing method comprises the following steps: providing an aluminum conductive section; stamping the end part of the aluminum conductive section to obtain a flat end; providing a copper connecting section, and bending the copper connecting section by the copper connecting section; the copper connecting section and the flat end are welded, and a composite end is obtained; and an insulating layer is arranged outside the composite end in a sleeving mode, thermal shrinkage treatment is conducted on the insulating layer, and the aluminum conductive piece is obtained. The bending part of the copper connecting section is bent to obtain the required bending shape, the bending shape part is flattened after the composite end is welded, the insulation layer can be sleeved conveniently, and stress generated by thermal shrinkage of the insulation layer enables the bending part to recover the bending shape. The composite end sleeved with the insulating layer does not need to be bent for the second time, and the situation that the insulating layer is pulled and deformed to be swelled or broken due to the fact that the composite end is bent again after being sleeved with the insulating layer is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of processing conductive parts of new energy electric vehicles, and more specifically, to an end processing method of an aluminum conductive part and the aluminum conductive part. Background Art

[0002] Conductive parts are the components with the highest cost in the high-voltage connector harness of electric vehicles. The traditional conductor materials are mainly copper and copper alloys. Copper has good electrical and mechanical properties and is an ideal material for electrical conduction. In the context of the development of charging power towards high-power charging, the current charging technology standards have increased the maximum allowable charging current to 800A, and will develop towards 1000A and higher in the future. In the absence of additional cooling measures on the vehicle end, when the current increases, according to Joule's law (Q = I 2 Rt), the conductor resistance needs to be reduced to prevent the vehicle from thermal failure and other problems. An effective measure to reduce resistance is to increase the conductor cross-sectional area. Generally, 120mm 2 The maximum current carrying capacity of copper cable is 500A. To obtain a higher current carrying capacity, the cross-sectional area of ​​the cable should be larger than 120mm. 2 Such a large size will lead to problems such as overweight of the wire harness and excessive bending radius. Therefore, lightweight conductors such as aluminum bars or aluminum rods will have an opportunity to be used.

[0003] Aluminum busbars can reduce the weight of conductive parts, which is beneficial to the overall lightweight of electric vehicles. Copper busbars have high conductivity and low energy loss. Therefore, the composite conductive busbars of aluminum busbars and copper terminals are used in the conductive parts of electric vehicles, which can give full play to the lightweight and low-cost advantages of aluminum, while taking advantage of the high conductivity of copper.

[0004] In the prior art, after the aluminum busbar and the copper terminal are welded, a heat shrink tube is put on for sealing and protection, and then the terminal is bent into a desired shape to adapt to the installation in the vehicle. However, the process of putting the tube on first and then bending will cause the heat shrink tube at the bend to bulge or even be damaged, resulting in the risk of leakage or short circuit. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide an end processing method of an aluminum conductive part and an aluminum conductive part to solve the problem of bulging and damage of the insulation layer during bending of the welded copper connecting section, thereby avoiding leakage or short circuit.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] The present invention provides a method for processing the end of an aluminum conductive member, comprising the following steps:

[0008] Provide aluminum conductive segments;

[0009] Stamping treatment is carried out on the end of the aluminum conductive section to obtain a flat end;

[0010] A copper connection section is provided, and the copper connection section is bent;

[0011] The copper connection section is welded to the flat end to obtain a composite end;

[0012] An insulating layer is sleeved outside the composite end, and heat shrinkage treatment is carried out on the insulating layer to obtain the aluminum conductive part.

[0013] The present invention also provides an aluminum conductive part, including:

[0014] An aluminum conductive section, the end of the aluminum conductive section includes a flat end;

[0015] A copper connection section, the copper connection section is welded to the flat end;

[0016] A metal transition layer, the metal transition layer is located between the flat end and the copper connection section, and the metal transition layer connects the flat end and the copper connection section; the material of the metal transition layer is silver, titanium, tin or nickel.

[0017] Implementing the embodiments of the present invention will have the following beneficial effects:

[0018] On the one hand, the end treatment method of the aluminum conductive part provided by the embodiment of the present invention first bends the copper connection section to obtain the required bent shape, and then the bent copper connection section is flattened after the composite end is welded, which is convenient for sleeving the insulating layer. After that, the stress generated by the heat shrinkage of the insulating layer makes the copper connection section return to the bent shape. The composite end after sleeving the insulating layer does not need to be bent twice, avoiding the insulating layer from being stretched and deformed to bulge or break after bending.

[0019] On the other hand, a metal transition layer is provided between the aluminum conductive section and the copper connection section in the aluminum conductive part provided by the embodiment of the present invention, which blocks the direct contact between aluminum and copper, reduces the potential difference, prevents electrochemical corrosion, improves the reliability of the connection between copper and aluminum, and reduces the resistance to avoid local heating. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Among them:

[0022] Figure 1Schematic flow chart of the end treatment method for the aluminum conductive part provided by the embodiment of the present invention.

[0023] Figure 2 Top view of an aluminum conductive part provided by the embodiment of the present invention.

[0024] Figure 3 For Figure 2 A sectional view taken along the line A - A' in

[0025] Figure 4 Schematic diagram of a copper connection section in the aluminum conductive part provided by the embodiment of the present invention. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0027] Referring to Figure 1 , the embodiment of the present invention provides an end treatment method for an aluminum conductive part, including the following processes:

[0028] 1) Provide an aluminum conductive section; specifically, the aluminum conductive section can be an aluminum bar or an aluminum rod, etc.

[0029] 2) Perform stamping treatment on the end of the aluminum conductive section to obtain a flat end.

[0030] 3) Provide a copper connection section.

[0031] 4) Bend the copper connection section.

[0032] 5) Weld the copper connection section to the flat end to obtain a composite end; specifically, the welding method is polymer diffusion welding, ultrasonic welding, friction stir welding or brazing.

[0033] 6) Sheath an insulating layer on the composite end and perform heat shrinkage treatment on the insulating layer to obtain an aluminum conductive part.

[0034] Optionally, the above end treatment is performed on both ends of the aluminum conductive part, that is, copper connection sections are welded to both ends of the aluminum conductive section; or, the above end treatment is performed on one end of the aluminum conductive part, for example, other end treatment methods are used for the other end, such as welding a copper connection section to one end of the aluminum conductive section, stamping and punching holes at the other end of the aluminum conductive section, welding a copper ring or a copper column in the hole for connecting with an external copper connector, and then, for example, after stamping the other end of the aluminum conductive section and sheathing a copper cap, punching holes together, and then welding a copper ring or a copper column in the hole, and the copper cap increases the connection area with the external copper connector.

[0035] The aluminum conductive part provided in this embodiment is connected to an external copper conductive part through a copper connecting section. The copper connecting section can absorb the vibration and impact during the operation of the tram, avoiding connection failure caused by mechanical stress. The copper connecting section is bent to adapt to the installation of the vehicle. In this embodiment, the copper connecting section is first bent to obtain the required bent shape, and then the bent shape is partially flattened after the composite end is welded, which is convenient for sleeving the insulating layer. After that, the stress generated by the heat shrinkage of the insulating layer causes the bent part to recover the bent shape. The composite end after sleeving the insulating layer does not need to be bent again, avoiding the tensile deformation of the insulating layer and causing bulging or cracking after bending the insulating layer.

[0036] Further, in a specific embodiment, before welding and after bending, it further includes: laser cleaning the first end copper connecting section and the flat end.

[0037] In this embodiment, laser cleaning is performed before welding the copper connecting section and the flat end to remove the oxide layer, avoiding impurities from affecting the conductivity of the aluminum conductive part.

[0038] Further, in a specific embodiment, before welding, it further includes: forming a metal transition layer between the flat end and the copper connecting section, and the material of the metal transition layer is selected from silver, titanium, tin or nickel.

[0039] Preferably, a metal transition layer is formed on the surface of the copper connecting section. Compared with forming a metal transition layer on the flat end, the copper connecting section does not require a mask, is convenient to operate, and a metal transition layer can be formed on the whole copper connecting section. While the copper connecting section plays the role of copper-aluminum section transition, the metal transition layer also plays the role of preventing the surface of the copper connecting section from oxidizing, and there is no need to further weld nickel sheets or tin sheets to prevent the copper connecting section from oxidizing at the end of the copper connecting section.

[0040] In this embodiment, a metal transition layer is formed between the flat end and the copper connecting section. The metal transition layer is used to block the direct contact between aluminum and copper, reduce the potential difference, prevent electrochemical corrosion, improve the reliability of the connection between copper and aluminum, and reduce the resistance to avoid local heating. Further, the copper connecting section, the metal transition layer and the flat end are welded to obtain a composite end. Through welding, the contact surfaces of the metal transition layer with aluminum or copper are all welded, which not only improves the welding strength, but also improves the welding quality of the welding interface between the metal transition layer and copper or aluminum.

[0041] Further, the thickness of the metal transition layer is 0.8μm - 6μm. If the metal transition layer is too thin, it may not be able to effectively block, and if the metal transition layer is too thick, it may increase the resistance or affect the mechanical properties.

[0042] In some alternative embodiments, the end treatment method of the aluminum conductive part includes:

[0043] 1) Provide an aluminum conductive section.

[0044] 2) Stamp the end of the aluminum conductive section to obtain a flat end.

[0045] 3) Provide a copper connection section.

[0046] 4) Bend the copper connection section.

[0047] 5) Punch a hole at one end of the copper connection section to obtain a mounting hole for facilitating connection with an external copper conductive section. When punching the hole, the bent copper connection section will be flattened to a certain extent.

[0048] 6) Weld the other end of the copper connection section to the flat end to obtain a composite end. During the welding process, it is necessary to fix the workpiece or apply pressure. The bent copper connection section is prone to being flattened by external forces during welding, which is convenient for sleeving an insulating layer in the next step.

[0049] 7) Sleeve an insulating layer on the composite end and perform heat shrinkage treatment on the insulating layer to obtain an aluminum conductive component. Specifically, the insulating layer is a heat shrinkable tube, and the stress generated by the heat shrinkage of the heat shrinkable tube makes the copper connection section return to its bent shape.

[0050] Optionally, the copper connection section can be a rigid component or a flexible component.

[0051] Further, the preparation method of the copper connection section includes:

[0052] 1) Provide copper foil. 2) Stack multiple layers of copper foil to obtain a copper stack. 3) Perform polymer diffusion welding on the copper stack to obtain a copper connection section.

[0053] In this embodiment, the copper connection section is a flexible component. The aluminum conductive component provided in this embodiment is connected to an external copper conductive component through the copper connection section. The copper connection section can absorb vibrations and impacts during the operation of the tram and avoid connection failure caused by mechanical stress. The copper connection section is obtained by stacking and welding copper foils. The stacked structure disperses stress, improves the flexibility of the copper connection section, and also facilitates the bending and forming of the copper connection section.

[0054] Further, a metal transition layer is also stacked on one side of the copper stack, and the copper stack and the metal transition layer are subjected to polymer diffusion welding together.

[0055] In some alternative embodiments, the metal transition layer is a metal density gradient transition layer, and the density of the metal density gradient transition layer gradually increases in the direction from the aluminum conductive section to the copper connection section.

[0056] Exemplarily, when the metal transition layer is a nickel transition layer, the lattice structures and physical properties of copper and nickel (such as the coefficient of thermal expansion) are relatively close. A dense nickel layer can better bond with copper, reducing the interface resistance and ensuring good electrical conductivity; copper has high electrical conductivity and mechanical strength, and a dense nickel layer can ensure the stability of current transmission and the reliability of mechanical connection. The lattice structures and physical properties of aluminum and nickel are quite different, and a sparse nickel layer can better adapt to the thermal expansion and mechanical deformation of aluminum; the sparse nickel layer can also reduce the interface stress concentration and avoid cracks or peeling caused by the mismatch of the coefficient of thermal expansion.

[0057] In some alternative embodiments, the metal transition layer may be a metal foil or a metal coating.

[0058] Optionally, the metal transition layer is a metal foil. By laminating metal foils with different densities between the flat end and the copper connecting section, and then performing polymer diffusion welding to form a metal density gradient transition layer.

[0059] Optionally, the metal transition layer is a metal coating. A metal transition layer is formed on the flat end or the copper connecting section by vacuum evaporation.

[0060] It should be noted that vacuum evaporation is to heat the metal to evaporate it in a high-vacuum environment and then deposit it into a film on the substrate. The vacuum evaporation method can obtain a high-purity, well-bonded, and uniform coating. Compared with the magnetron sputtering method, the equipment cost of magnetron sputtering is high and the process is complex. Compared with the electroplating method, the electroplating method requires chemical solutions and is prone to environmental pollution problems. Preferably, a metal transition layer is formed on the surface of the copper connecting section by vacuum evaporation, which is convenient for production operation. Specifically, the process of forming the metal transition layer includes: placing the copper connecting section in a vacuum coating device, placing the metal particles to be evaporated, and the metal particles obtain energy and are converted into gas and deposited on the copper connecting section to form a metal transition layer. The background vacuum degree of the vacuum coating device is 1.0×10 -5 Torr~1.0×10 -6 Torr, and the deposition rate of the metal transition layer is 0.1nm / s~2nm / s.

[0061] Furthermore, the metal transition layer includes at least two density layers, which can be two layers, three layers, four layers or other multi-layer density layers to achieve density gradient. Specifically, the metal transition layer includes a first density layer and a second density layer. The first density layer is close to the copper connecting section, and the second density layer is close to the flat end. The density of the first density layer is greater than that of the second density layer.

[0062] It should be noted that the density of the metal transition layer affects the interface bonding strength, electrical conductivity and mechanical properties. The vacuum evaporation method can control the density of the metal transition layer by controlling the deposition rate.

[0063] When the deposition rate is low, atoms have enough time to migrate on the substrate surface to form a more ordered and compact structure, thereby improving the density. While during high-speed deposition, atoms accumulate rapidly and have insufficient migration time, easily forming a porous or columnar structure and resulting in a decrease in density.

[0064] Furthermore, the deposition rate of the second density layer is greater than that of the first density layer. Preferably, the deposition rate of the first density layer is 0.1 nm / s to 0.8 nm / s, and the deposition rate of the second density layer is 0.9 nm / s to 2 nm / s.

[0065] Furthermore, the thickness of the first density layer is 0.4 μm to 3 μm, and the thickness of the second density layer is 0.4 μm to 3 μm. Preferably, the thickness of the first density layer is 0.8 μm to 1.2 μm, and the thickness of the second density layer is 1.2 μm to 1.8 μm. The first density layer is thin and dense, avoiding brittle fracture caused by excessive thickness; the second density layer is thick and slightly porous, which can match the thermal expansion coefficient of aluminum, and the porous structure can absorb welding residual stress, thereby improving the connection stability of the copper transition section.

[0066] In some alternative embodiments, the aluminum conductive segment includes a conductor core and an insulating layer covering the conductor core. Before the punching process of the aluminum conductive segment, it further includes: circumferentially cutting the insulating layer to remove the end insulating layer to obtain an exposed end, stamping the exposed end to obtain a flat end, and punching the flat end.

[0067] Furthermore, the aluminum conductive segment further includes an armored layer covering the conductor core and the insulating layer. Before circumferentially cutting the insulating layer, it further includes: circumferentially cutting the armored layer to remove the end armored layer to obtain an exposed insulating end, and circumferentially cutting the insulating layer of the exposed insulating end.

[0068] Combined Figures 2 to 4 , an embodiment of the present invention further provides an aluminum conductive component including: an aluminum conductive segment 1, a copper connection segment 2, and a metal transition layer 3.

[0069] The aluminum conductive segment 1 is welded to the copper connection segment 2; the metal transition layer 3 is located between the flat end 11 and the copper connection segment 2, the metal transition layer 3 connects the flat end 11 and the copper connection segment 2, and the material of the metal transition layer 3 is silver, titanium, tin, or nickel.

[0070] Specifically, the aluminum conductive part is suitable for connecting the charging socket and the battery pack inside the electric vehicle. The aluminum conductive section includes a conductive main body 12 and a flat end 11 connected to each other. The conductive main body 12 can be preformed into an adapted bent shape according to the installation space where it is located, which helps the conductive main body 12 to be accommodated in the environment of the vehicle body with limited space through bent arrangement. Further, the aluminum conductive part includes a conductor core and an insulating layer covering the conductor core, or the aluminum conductive part further includes an armor layer covering the conductor core and the insulating layer, and the conductor core includes a conductive main body 12 and a flat end 11 connected to each other.

[0071] In the aluminum conductive part provided in this embodiment, a metal transition layer 3 is arranged between the flat end 11 and the copper connection section 2. The metal transition layer 3 blocks the direct contact between aluminum and copper, reduces the potential difference, prevents electrochemical corrosion, improves the reliability of the connection between copper and aluminum, and reduces the resistance to avoid local heating.

[0072] In an optional embodiment, the aluminum conductive section 1 includes a flat end 11; the copper connection section 2 includes a first end 21 and a bent part 22 connected in sequence. The metal transition layer 3 is located between the flat end 11 and the first end 21, and the metal transition layer 3 connects the flat end 11 and the first end 21. The copper connection section 2 is welded to the flat end 11 through the first end 21, and the copper connection section 2 is convenient for installation on the vehicle through the bent part.

[0073] Further, the copper connection section 2 further includes a second end 23, and the first end 21, the bent part 22, and the second end 23 are connected in sequence; an installation hole 231 penetrating through the second end 23 along the thickness direction of the second end 23 is provided on the second end 23. It is connected to an external copper conductive part through the installation hole 231.

[0074] The copper connection section 2 can be a rigid part or a flexible part. Preferably, the copper connection section 2 is a flexible part. The copper connection section 2 is connected to an external copper conductive part, and the flexibility of the copper connection section 2 can absorb the vibration and impact during the operation of the tram and avoid connection failure caused by mechanical stress.

[0075] Further, the aluminum conductive part further includes an insulating layer 4, and the insulating layer 4 covers the flat end 11 and the first end 21. Specifically, the insulating layer 4 is a heat shrinkable tube, and the insulating layer 4 covers the outer surfaces of the flat end 11 and the first end 21 to avoid electric leakage or short circuit.

[0076] In some optional embodiments, the thickness of the metal transition layer 3 is 0.8 μm to 6 μm. If the metal transition layer 3 is too thin, it may not be able to effectively block, and if the metal transition layer 3 is too thick, it may increase the resistance or affect the mechanical properties.

[0077] Further, the metal transition layer 3 can be a metal foil or a metal coating.

[0078] Further, the metal transition layer 3 is a metal density gradient transition layer, and the density of the metal density gradient transition layer gradually increases in the direction from the aluminum conductive section 1 to the copper connection section 2. Optionally, the metal transition layer 3 is a metal foil, and different density metal foils are laminated between the flat end 11 and the copper connection section 2, and then a metal density gradient transition layer is formed by polymer diffusion welding. Optionally, the metal transition layer 3 is a metal coating, and a metal transition layer is formed on the flat end 11 or the copper connection section 2 by vacuum evaporation.

[0079] Optionally, the metal transition layer 3 includes at least two density layers, which can be two, three, four or more density layers to achieve density gradient.

[0080] Specifically, the metal transition layer 3 includes a first density layer and a second density layer. The density of the first density layer is greater than that of the second density layer. The copper connection section 2, the first density layer, the second density layer, and the flat end 11 are connected in sequence. Exemplarily, the metal transition layer is a nickel transition layer. The lattice structures and physical properties (such as thermal expansion coefficient) of copper and nickel are relatively close. The first density layer is a dense nickel layer, and the dense nickel layer can better bond with copper, reduce the interface resistance, and ensure good electrical conductivity; copper has high electrical conductivity and mechanical strength, and the dense nickel layer can ensure the stability of current transmission and the reliability of mechanical connection. The lattice structures and physical properties of aluminum and nickel are quite different, and the sparse nickel layer can better adapt to the thermal expansion and mechanical deformation of aluminum; the first density layer is a sparse nickel layer, and the sparse nickel layer can also reduce the interface stress concentration and avoid cracks or peeling caused by the mismatch of thermal expansion coefficients.

[0081] The following are specific embodiments:

[0082] Embodiment 1

[0083] (1) Provide an aluminum busbar, and perform stamping treatment on the end of the aluminum busbar to obtain a flat end.

[0084] (2) Provide a copper connection section, perform vacuum evaporation on the surface of the copper connection section at a deposition rate of 0.1 nm / s to obtain a nickel transition layer, and the thickness of the nickel transition layer is 0.8 μm.

[0085] (3) Bend the nickel-plated copper connection section, and after bending, ultrasonically weld the copper connection section to the flat end to obtain a composite end.

[0086] (4) Sheath a heat shrinkable tube on the composite end and perform heat shrinkage treatment to obtain an aluminum conductive component.

[0087] Embodiment 2

[0088] (1) Provide an aluminum busbar, and perform stamping treatment on the end of the aluminum busbar to obtain a flat end.

[0089] (2) Provide a copper connection segment, perform vacuum evaporation on the surface of the copper connection segment at a deposition rate of 2 nm / s to obtain a nickel transition layer with a thickness of 6 μm.

[0090] (3) Bend the nickel-plated copper connection segment, and after bending, ultrasonically weld the copper connection segment to the flat end to obtain a composite end.

[0091] (4) Sheath the composite end with a heat shrinkable tube and perform heat shrinkage treatment to obtain an aluminum conductive part.

[0092] Example 3

[0093] (1) Provide an aluminum conductive busbar, perform stamping on the end of the aluminum conductive busbar to obtain a flat end.

[0094] (2) Provide a copper connection segment, perform the first vacuum evaporation on the surface of the copper connection segment at a deposition rate of 0.1 nm / s to obtain a first nickel transition layer with a thickness of 0.4 μm; then perform the second vacuum evaporation at a deposition rate of 0.9 nm / s to obtain a second nickel transition layer with a thickness of 0.4 μm.

[0095] (3) Bend the nickel-plated copper connection segment, and after bending, ultrasonically weld the copper connection segment to the flat end to obtain a composite end.

[0096] (4) Sheath the composite end with a heat shrinkable tube and perform heat shrinkage treatment to obtain an aluminum conductive part.

[0097] Example 4

[0098] (1) Provide an aluminum conductive busbar, perform stamping on the end of the aluminum conductive busbar to obtain a flat end.

[0099] (2) Provide a copper connection segment.

[0100] (3) Provide a nickel sheet with a thickness of 0.8 μm. Bend the copper connection segment, and after bending, stack the copper connection segment, nickel sheet, and flat end in sequence, and then perform ultrasonic welding to obtain a composite end.

[0101] (4) Sheath the composite end with a heat shrinkable tube and perform heat shrinkage treatment to obtain an aluminum conductive part.

[0102] Comparative Example 1

[0103] The difference between Comparative Example 1 and Example 1 is that nickel plating is not performed on the surface of the copper connection segment in Comparative Example 1.

[0104] Comparative Example 2

[0105] The difference between Comparative Example 2 and Example 4 is that the thickness of the nickel sheet in Comparative Example 2 is 0.1 mm.

[0106] Test Example

[0107] After the aluminum conductive parts in Examples 1 to 4 and Comparative Examples 1 to 2 were processed, the conductivity was measured by the four-probe method, and the test results are shown in the following table.

[0108] Table of conductivity of aluminum conductive parts in Examples 1 to 2 and Comparative Examples 1 to 2

[0109]

[0110]

[0111] Result description:

[0112] Examples 1 to 4 all have relatively high conductivity, while the conductivity in Comparative Example 1 is only 63% IACS. Since nickel was not plated on the surface of the copper connection section in Comparative Example 1, when copper and aluminum dissimilar materials were welded, the potential difference was large, the resistance at the interface increased, and the conductivity decreased.

[0113] Among them, the conductivity of Example 1 is 88% IACS, the conductivity of Example 2 is 82% IACS, and the conductivity of Example 3 is 92% IACS. In Example 3, nickel transition layers with decreasing density were sequentially formed on the surface of the copper connection section. The dense nickel layer can better bond with copper, reduce the interface resistance, and ensure good conductivity. The sparse nickel layer can better adapt to the thermal expansion and mechanical deformation of aluminum, reduce the interface stress concentration. Compared with Examples 1 to 2, the conductivity of Example 3 is improved.

[0114] The conductivity in Comparative Example 2 is 45% IACS. The main purpose of setting a nickel transition layer between copper and aluminum is to reduce galvanic corrosion, improve the bonding performance, and alleviate the problems caused by the difference in thermal expansion coefficients. However, in Comparative Example 2, the nickel layer is too thick, the interface stress increases, and the too thick nickel layer causes interlayer peeling or cracking due to the accumulation of thermal stress during temperature change, and the bonding strength decreases, resulting in a decrease in conductivity. Therefore, the conductivity of Example 4 is better than that of Comparative Example 2.

[0115] The above examples only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of this invention patent shall be subject to the appended claims.

Claims

1. A method for treating the end of an aluminum conductive part, characterized in that, It includes the following processes: Provide an aluminum conductive section; Perform stamping on the end of the aluminum conductive section to obtain a flat end; Provide a copper connection section and bend the copper connection section; Weld the copper connection section to the flat end to obtain a composite end; Sheath an insulating layer on the composite end and perform heat shrinkage treatment on the insulating layer to obtain the aluminum conductive part.

2. The end treatment method of the aluminum conductive part according to claim 1, characterized in that Before the welding, it further includes: Form a metal transition layer between the flat end and the copper connection section, and the material of the metal transition layer is selected from silver, titanium, tin or nickel.

3. The end treatment method of the aluminum conductive part according to claim 2, characterized in that, The thickness of the metal transition layer is 0.8 μm to 6 μm.

4. The end treatment method of the aluminum conductive part according to any one of claims 2 to 3, characterized in that, The metal transition layer is a metal density gradient transition layer, and the density of the metal density gradient transition layer gradually increases in the direction from the aluminum conductive section to the copper connection section.

5. The end treatment method of the aluminum conductive part according to any one of claims 2 to 3, characterized in that, The preparation method of the copper connection section includes the following processes: Stack multiple layers of copper foils to obtain a copper stack; Perform polymer diffusion welding on the copper stack to obtain the copper connection section.

6. The end treatment method of the aluminum conductive part according to claim 5, characterized in that, Stack the metal transition layer on one side of the copper stack and perform polymer diffusion welding on the copper stack and the metal transition layer together; Alternatively, form the metal transition layer on the flat end or the copper connection section by vacuum evaporation.

7. The end treatment method of the aluminum conductive part according to claim 1, characterized in that, Before the welding and after the bending, it further includes: Perform laser cleaning on the copper connection section and the flat end.

8. An aluminum conductive part, characterized in that, It includes: An aluminum conductive section, and the end of the aluminum conductive section includes a flat end; A copper connection section, and the copper connection section is welded to the flat end; A metal transition layer, the metal transition layer is located between the flat end and the copper connection section, and the metal transition layer connects the flat end and the copper connection section; the material of the metal transition layer is silver, titanium, tin or nickel.

9. The aluminum conductive part according to claim 8, characterized in that, The thickness of the metal transition layer is 0.8 μm to 6 μm.

10. The aluminum conductive part according to any one of claims 8 to 9, characterized in that, The metal transition layer is a metal density gradient transition layer, and the density of the metal density gradient transition layer gradually increases in the direction from the aluminum conductive section to the copper connection section.

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