A high-conductivity aluminum alloy material for a new energy automobile bus conductor and a preparation method of the bus conductor

Abstract

The application belongs to the field of light high-conductive metal materials, and relates to a high-conductive aluminum alloy material for a new energy automobile bus conductor and a preparation method of the bus conductor. The aluminum alloy material is composed of: aluminum 97.22-99.35%, magnesium 0.35-0.8%, silicon 0.3-0.7%, iron ≤0.5%, lanthanum or cerium 0.05-0.3%, titanium ≤0.1%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.06%, and zinc ≤0.1%. The method takes 6101 aluminum alloy as a base material, and solves the profile cracking problem of the high-conductive aluminum alloy in the large-curvature deformation process through a process flow of trace element regulation, multi-stage strong cold crystallization, soaking rolling deformation, solid solution stress relief annealing, three-dimensional bending forming and artificial aging treatment. The application purifies the alloy melt, refines the alpha-Al grains and improves the strength and plasticity of the alloy through the composite addition of rare earth elements La or Ce and refining agents. The mechanical properties, conductive properties and good three-dimensional bending properties of the high-conductive aluminum alloy are simultaneously up to the standards.

Description

Technical Field

[0001] This invention belongs to the field of lightweight, highly conductive metallic materials, and relates to a highly conductive aluminum alloy material for busbar conductors in new energy vehicles and a method for preparing the busbar conductor. Background Technology

[0002] In high and low voltage conductor harnesses used in new energy vehicles, copper wires remain the mainstream choice due to their superior conductivity. However, due to copper's relatively high density and cost, aluminum wires are gradually becoming an important alternative in the high-voltage harness field, driven by the dual pursuit of "lightweighting" and "cost reduction and efficiency improvement" in new energy vehicles. Statistics show that, to ensure the same conductivity, aluminum wire weighs 50% of copper wire, its raw material cost is 27% of copper wire, and its component cost is 58% of copper wire. However, aluminum alloys have lower ductility than copper alloys at the same strength level. During the manufacturing process of components used in new energy vehicle busbar conductors, aluminum alloy parts are prone to cracking during bending deformation, affecting workpiece quality, causing conductor breakage, and potentially leading to uncontrollable risks such as loss of control in new energy vehicles. Therefore, controlling the entire process of aluminum alloy busbar conductors, from melting and heat treatment to deformation, is of great significance to the application of aluminum alloy workpieces and the development of new energy vehicles.

[0003] According to patent (CN105950893B), increasing the conductivity of aluminum electrical conductors in China by 0.1% IACS can reduce energy loss by 10 billion kilowatt-hours annually. Therefore, maximizing conductivity while meeting service strength requirements can significantly reduce energy consumption. Patents (CN118143074A, CN110093536B, CN115740057A) disclose high-conductivity 6101 aluminum alloy coils and their preparation methods. The obtained aluminum busbar coils for new energy applications have conductivity, tensile strength, and elongation of 57.8% IACS, 190MPa, and 13.5%, respectively; the obtained aluminum busbar coils for battery conductors have conductivity, tensile strength, yield strength, and elongation of 58.5% IACS, 185MPa, 150MPa, and 14%, respectively; and the obtained aluminum alloy coils and strips for power supply in new energy vehicles have conductivity, tensile strength, yield strength, and elongation of 59.5% IACS, 105MPa, 55MPa, and 18%, respectively.

[0004] Patent (CN116748326A) discloses a conductive profile of 6101 aluminum alloy, its preparation method, and its application. The wall thickness of the formed conductive profile is no more than 8mm, and its conductivity is ≥56% IACS, tensile strength ≥185MPa, yield strength ≥150MPa, straightness ≤0.5mm / m, and cross-sectional profile ≤0.2mm. Patent (CN117587306A) discloses a 6101 aluminum alloy sheet with improved alloy strength and conductivity, and its preparation method. The prepared alloy has a tensile strength of 177.3MPa~201.8MPa, but its conductivity is only 42.5%IACS~43.99%IACS. Patents (CN108546850A and CN116356184A) respectively disclose a production method for a high-conductivity 6101 aluminum alloy sheet and a 6101 aluminum alloy sheet for automotive applications, its preparation method, and its application. Among them, the sheet material prepared by patent (CN108546850A) has an electrical conductivity of 59.75% IACS, a tensile strength of 116 MPa, a yield strength of 85 MPa, and an elongation of 29%. The sheet material prepared by patent (CN116356184A) has an electrical conductivity ≥56%, a tensile strength ≥185 MPa, and a yield strength of 155~175 MPa. Patent (CN111850350A) discloses an aluminum alloy material for fuses in new energy vehicles and its preparation method. By adding mixed rare earth elements to 6101 aluminum alloy raw materials, the tensile strength of the material is approximately 195 MPa, and the electrical conductivity is approximately 56% IACS. Patent (CN117265348A) discloses a medium-strength, high-conductivity aluminum alloy sheet material and its preparation method. The prepared aluminum alloy sheet material has an electrical conductivity above 53% IACS, a tensile strength above 187 MPa, and a hardness greater than 71 HV.

[0005] In addition, the papers (Zhang Ruifeng, Dong Yaguang, Tan Rui, Zhao Hongliang. Influence of mixed rare earth elements on the as-cast microstructure of 6101 aluminum alloy for overhead conductors, Henan Science and Technology Innovation Driven, 2016.09) and (Peng Xiaolan, Wang Hongcheng. Study on performance optimization of Al-Mg-Si system 6101 aluminum alloy for radiators, Journal of Dongguan University of Technology, 2015, 22(3):7-11) reported that adding rare earth elements and B and Gd elements can improve the grain size, mechanical properties, electrical conductivity and thermal conductivity of 6101 aluminum alloy. The dissertations (Huang Jiajun, Study on composition improvement and performance balance optimization of 6101 alloy for subway conductor rails, South China University of Technology, 2022.4) and (Liu Zhenxing, Study on aging heat treatment of 6101 aluminum alloy, Central South University, 2013.5) studied the influence of different elements and aging regimes on the precipitation path of 6101 aluminum alloy.

[0006] In addition, patent (CN117620614A) discloses a bending forming method for aluminum alloy cylinders with a large diameter-to-thickness ratio. Through process optimization, it solves the problem of reduced manufacturing precision caused by wavy deformation in large diameter-to-thickness aluminum alloy cylinders. Patent (CN117696700A) discloses an aluminum alloy tube bending forming equipment and its bending forming process. Through optimization of the equipment structure, it achieves precise bending at multiple bends while effectively reducing scratches on the product and ensuring product quality. Patent (CN118635328A) mentions a method and apparatus for bending forming aluminum alloy profiles. Through a detachable fixing groove, it expands the range of materials that can be formed. Through process optimization of the bending process, it achieves low product springback and fewer forming defects.

[0007] Patent (CN116287877B) discloses an aluminum alloy rod for high-bending-performance aluminum alloy conductors, its preparation method, and its application. An 8030 aluminum alloy rod is formed through melting, casting, and rolling; this rod can be used to prepare aluminum alloy conductors. Patent (CN120138527A) discloses a high-toughness, bend-resistant aluminum alloy material and its preparation method. Through the synergistic effect of boron nitride nanofibers and alumina nanoparticles, lithium oxidation is inhibited, and the dispersion of boron nitride nanofibers and alumina nanoparticles is promoted, thus promoting the densification of the aluminum alloy and improving the material's strength and toughness. Patent (CN119114710B) discloses a bending forming method for wide-side aluminum alloy profile components. Through process optimization of the bending process, side-bending defects in the components are eliminated, significantly improving the contour accuracy of such components after forming, reducing production steps, and accelerating the production cycle of such components.

[0008] The paper (Xu Wugang, Hao Yuxi, Liu Peng, Wu Yanlin, Jia Zhongde. Influence of coarse grains on cracking during bending of aluminum alloy profiles, Aluminum Processing, 2025 (01): 38-41) reports the influence of 6061 aluminum alloy composition and extrusion process on the coarse grains of the profile cross section, as well as the influence of coarse grains on the subsequent bending forming process of the profile. The paper (Zhang Xin, Lin Chuang, Wang Shunhong, Li Chunjiang, Yuan Meng. Research on precise stretch bending forming process of double-bend aluminum alloy profile parts, Forging Equipment and Manufacturing Technology, 2026, 61(01): 144-148) addresses the problem of severe springback after stretch bending of trapezoidal double-bend aluminum alloy profile parts for aircraft. By optimizing the stretch bending die, precise one-time forming of the parts is achieved, which greatly reduces the amount of manual shaping work and improves the surface quality.

[0009] In summary, current research primarily focuses on aluminum alloy materials or the optimization of deformation processes, failing to integrate material preparation with component forming to create a complete, end-to-end manufacturing process. Due to the inherent trade-off between strength and conductivity, 6101 aluminum alloys struggle to simultaneously achieve high strength and conductivity, often resulting in either mechanical or electrical properties failing to meet service requirements. Adding trace amounts of rare earth elements and refining agents offers a relatively simple, clean, and efficient way to synergistically improve the mechanical and electrical properties of aluminum alloys. Especially for alloys requiring mass production, subsequent component fabrication through deformation processes is crucial. Simpler and more easily implemented process optimizations can significantly reduce production costs and time, thereby enabling the upgrading of the large-scale industrial chain and driving economic development. Summary of the Invention

[0010] The purpose of this invention is to provide a high-conductivity aluminum alloy material for busbar conductors in new energy vehicles and a method for preparing the busbar conductor. The method utilizes existing production lines and a newly designed "melting-casting-rolling-heat treatment-forming" process flow for the preparation of materials and parts. The preparation process and forming technology used in this invention can solve the cracking problem of high-conductivity aluminum alloy parts during the forming process, preventing parts from breaking and becoming unusable after forming, and greatly improving the part yield, thus meeting the service conditions of new energy vehicle components. The main processes of this invention are all mechanized, reducing the labor intensity of operators and allowing for mass production.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-conductivity aluminum alloy material for busbar conductors in new energy vehicles, comprising, by mass percentage: aluminum 97.22~99.35%, magnesium 0.35~0.8%, silicon 0.3~0.7%, iron ≤0.5%, lanthanum or cerium 0.05~0.3%, titanium ≤0.1%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.06%, and zinc ≤0.1%.

[0012] A method for preparing a busbar conductor for a new energy vehicle includes the following steps: (1) According to the composition of the aluminum alloy material described in claim 1, take the alloy raw materials for smelting, add Al, Si and Mg elements in sequence during the smelting process, purify the material, add rare earth elements and continue smelting to obtain the alloy melt. (2) The above alloy melt is subjected to directional solidification casting using a multi-stage strong cooling process, and the cooling rate during the solidification process is controlled to obtain an ingot. (3) The ingot is subjected to homogenization heat treatment, rolling deformation treatment, solution treatment and quenching in sequence to obtain supersaturated solid solution plate material; (4) After stress-relief annealing, the above sheet material is subjected to three-dimensional bending and forming; (5) The formed parts are subjected to aging treatment to obtain a three-dimensional bending busbar conductor for new energy vehicles.

[0013] Further, in step (1), the raw materials provided for Al, Si, Mg and rare earth elements are: pure aluminum ingot, Al-Si master alloy, Al-Mg master alloy and Al-rare earth master alloy; the rare earth element is La or Ce. The pure aluminum ingot is smelted at 700℃~740℃; after adding Si, it is smelted at 700℃~740℃ for 10-30 minutes; the temperature is adjusted to 690℃~710℃, Mg is added, and the temperature is maintained for 10-30 minutes; the temperature is adjusted to 700℃~720℃, rare earth elements are added, and the mixture is stirred and allowed to stand for 10-30 minutes.

[0014] The purification process involves introducing a refining agent, argon, and chlorine into the melt. The refining agent, by mass percentage, comprises 40% sodium cryolite, 46% salt slag from the preparation of Al-5Ti-1B intermediate alloy by fluoride reaction, 10% aluminum fluoride, 2% calcium fluoride, and 2% potassium feldspar.

[0015] The purification process involves introducing 0.2 to 1.0 m³ of argon gas into the melt at a melt temperature of 700℃~740℃ and a rotor speed of 300~500 rpm. 3 / h, chlorine gas 0.02~0.1 m 3 / h and refining agent 400~600 g / t, so that the hydrogen content in the melt is ≤0.10ml / 100gAl.

[0016] Further, in step (2), the temperature of the directional solidification is 720℃~740℃, and the cooling rate is adjusted by regulating the cooling water flow rate of the multi-stage strong refrigeration crystallizer to 20~100 m³ / h. 3 The process is achieved by using a casting speed of 20-100 mm / min, a temperature of 20-100℃, a casting speed of 20-100 mm / min, 15-25 cooling water sprays, and a liquid level height of 60-150 mm in the crystallizer.

[0017] Furthermore, in step (3), the temperature of the homogenization heat treatment is 460℃~490℃, and the holding time is 8~16h; The rolling deformation treatment includes hot rolling and cold rolling. The roughing temperature of the hot rolling treatment is 400~500℃, the finishing temperature is 200~300℃, the final rolling thickness of the rolled plate is 6~10 mm, and the thickness deformation per pass is 10~40 mm. The cold rolling treatment is carried out at room temperature, the final rolling thickness of the rolled plate is 1~6 mm, and the thickness deformation per pass is 1~2.5 mm. The solution treatment temperature is 490℃~550℃, and the holding time is 1~6 h; The quenching condition is water quenching.

[0018] Further, in step (4), the stress-relief annealing temperature is 100℃~200℃, the holding time is 30~90min, and after holding, it is air-cooled to room temperature; the three-dimensional bending forming temperature is 100~300°.

[0019] Further, in step (4), the tooling for three-dimensional bending is a bending forming mold, which includes a lower clamping mold (1) and a bending mold (2). The bending mold (2) can be rotated by a power source or manually. The lower part of the lower clamping mold (1) is detachably rotatably connected to the bending mold (2). The upper part of the lower clamping mold (1) consists of two symmetrical clamping blocks. Between the two clamping blocks is a placement groove for placing a plate-shaped straight strip (3). The middle part of the plate-shaped straight strip (3) is accommodated in the placement groove, and the two ends are... They pass through the placement groove respectively; the width of the placement groove can be adjusted by changing the lower clamping mold (1) to match the horizontally or vertically placed plate-shaped straight strip (3); a part is cut off on the same side of the two clamping blocks along the groove width direction, and the cut surface is rounded with the inner wall of the groove. The radius of the rounded corner is the radius to be bent of the plate-shaped straight strip (3); a protrusion is provided on the upper surface of the bending mold (2). The shape of the protrusion is not limited. As long as one end of the plate-shaped straight strip (3) is bent during the rotation of the bending mold (2); The specific process of the three-dimensional bending forming is as follows: After the sheet material is cut into a certain width of sheet-shaped straight strip (3), it enters the lower clamping mold (1). The bending mold (2) rotates 90° to perform a flat bending process on the sheet-shaped straight strip (3), with a springback of 2~10°. After the flat bending process is completed, the bending mold (2) returns to the center, and the sheet-shaped straight strip (3) is automatically fed forward 20-30cm to perform the next stage of vertical bending process. The lower clamping mold (1) of the vertical bending mold is controlled by the robotic arm to clamp the sheet material, and then the bending mold (2) rotates 90° to complete the vertical bending process. The springback of the vertical bending process is 2~8°.

[0020] Furthermore, in step (5), the aging treatment temperature is 180℃~220℃, and the heat preservation time is 8~25 h.

[0021] The principle of this invention is as follows: First, a high-conductivity aluminum alloy material is obtained through reasonable material composition design; then, through reasonable process flow and preparation process parameters, the α-Al grains are refined, the internal stress of the material is removed, and the plasticity and toughness of the alloy are improved, thereby greatly reducing the tendency to crack during the process of preparing the material into parts; finally, through the design of bending mold and the optimization of bending process, three-dimensional bending high-conductivity aluminum alloy parts for busbar conductors of new energy vehicles are prepared for mass production.

[0022] The beneficial effects of this invention are: Based on the manufacturing principle of high-conductivity 6101 aluminum alloy parts, a complete process flow from high-conductivity aluminum alloy material to part forming was designed. Through a full-chain manufacturing system of melting, casting, rolling, heat treatment, and forming, and with optimization of process parameters during the manufacturing process, this paper addresses the problems of easy cracking and low yield of new energy vehicle busbar conductors in the production process by optimizing continuous solidification and bending deformation process parameters, starting from material preparation, under existing tooling conditions, and targeting the large-scale manufacturing and application of new energy vehicle busbar conductors. This improves product quality and service reliability.

[0023] The three-dimensional bending processing method for high-conductivity aluminum alloy materials for new energy vehicles involved in this invention can be extended to the manufacturing field of aluminum alloy parts with complex shapes and large deformation, effectively solving the problem of cracking of parts caused by large deformation. Attached Figure Description

[0024] Figure 1 Schematic diagram of a multi-stage high-intensity cold crystallizer; Figure 2 This is a standard drawing for the three-dimensional bending of alloy samples, where the left figure represents a flat bend and the right figure represents a vertical bend; Figure 3 This is a schematic diagram of the mold for the flat bending process; where: 1. Lower clamping mold, 2. Bending mold, 3. Plate-shaped straight material, 4. Upper clamping mold; Figure 4 This is a schematic diagram of the mold for the vertical bending process; where: 1 is the lower clamping mold, and 2 is the bending mold; Figure 5 Damage diagram from finite element simulation of the bending point at 20℃; Figure 6 Damage diagram from finite element simulation of the bending point at 200℃; Figure 7 Damage diagram from a finite element simulation of a 300℃ flat bend; Figure 8 This is a physical image of the object after three-dimensional bending in Example 1; Figure 9 This is a physical image of the object after being 3D bent to resemble Scale 1; Figure 10 The microstructure of the sample produced in Comparative Example 2 is shown in the diagram. Figure 11 This is a photograph of the actual ingot produced for Comparative Example 3; Detailed Implementation

[0025] The preparation method of the busbar conductor for new energy vehicles is as follows: In its specific implementation, this invention uses high-conductivity aluminum alloy material for new energy vehicles. According to the mass percentage of each component, the smelted aluminum alloy composition is as follows: aluminum 97.22~99.35%, magnesium 0.35~0.8%, silicon 0.3~0.7%, iron ≤0.5%, lanthanum or cerium 0.05~0.3%, titanium ≤0.1%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.06%, and zinc ≤0.1%. First, a refining agent is prepared, with the following composition and content by mass percentage: 40% sodium cryolite, 46% fluoride salts (composition and preparation method are detailed in patent CN112301249A), 10% aluminum fluoride, 2% calcium fluoride, and 2% potassium feldspar. Then, alloy raw materials are prepared according to the above aluminum alloy composition requirements. Dry pure aluminum is added to a crucible, and the furnace is heated to 700℃~740℃ to melt the aluminum. Subsequently, silicon is added sequentially in the form of Al-Si and Al-Mg master alloys. Magnesium is added to the aluminum melt, the alloy melt is stirred and kept at a constant temperature; then, a refining agent and argon and chlorine are introduced into the melt for refining; subsequently, rare earth elements lanthanum or cerium are added to the alloy melt as Al-La master alloy or Al-Ce master alloy, respectively, and after stirring and settling, a homogeneous melt is obtained, which is then continuously cast into ingots; finally, the ingots are subjected to homogenization, rolling deformation, solution quenching, stress-relief annealing, three-dimensional bending deformation, and aging treatment in sequence to obtain three-dimensional bending high conductivity aluminum alloy parts for busbar conductors of new energy vehicles.

[0026] A method for preparing a busbar conductor for a new energy vehicle includes the following steps: (1) Prepare alloy raw materials according to the composition requirements of high conductivity aluminum alloy; (2) Place the pure aluminum ingots into the melting furnace and adjust the melt temperature to 700℃~740℃; (3) Add silicon to the melt in the form of an Al-Si master alloy and stir the alloy melt; (4) Reduce the temperature of the alloy melt to 690℃~710℃, add magnesium in the form of Al-Mg master alloy, and stir the alloy melt. (5) Heat the melt to 700℃~740℃, and introduce refining agent and argon and chlorine into the melt for purification treatment; (6) Adjust the temperature of the above aluminum alloy melt to 700℃~720℃, add rare earth elements La or Ce in the form of Al-La master alloy or Al-Ce master alloy, stir and keep the alloy melt at a constant temperature to obtain a uniform aluminum alloy melt. (7) Adjust the temperature of the aluminum alloy melt to 720℃~740℃ so that it enters the multi-stage strong cold crystallizer of the continuous casting equipment; (8) Construct a multi-stage strong cold crystallizer for continuous casting equipment, such as Figure 1 As shown, the crystallizer structure and cooling water system are based on patents (CN202725997U) and (CN203992288U), respectively. The crystallizer has a rectangular crystallizer cavity (580 mm thick, 1480 mm wide) at its center, containing liquid metal and solidified metal. A guide head is located at the bottom of the cavity to guide the solidified metal billet downwards. A multi-stage cooling system is symmetrically arranged on both sides of the crystallizer, with multiple cooling water channels on each side. Cooling water flows in from a storage tank and, through the multi-stage structure, provides high-intensity cooling to the crystallizer walls, thereby controlling the undercooling at each stage and promoting rapid ingot solidification. By controlling the casting speed, cooling water flow rate, number of cooling water jets, and cooling water temperature, an ingot with uniform microstructure (580 mm thick, 1480 mm wide) is obtained. (9) Heat the aluminum alloy ingot to 460℃~490℃ and hold for 8~16 h for homogenization heat treatment; (10) The ingot after homogenization heat treatment is subjected to rolling deformation treatment. The rough rolling temperature of the hot rolling process is 400~500℃, the final rolling temperature is 200~300℃, the final rolling thickness of the rolled plate is 6~10 mm, and the thickness deformation per pass is 10~40 mm; the cold rolling process is carried out at room temperature, the final rolling thickness of the rolled plate is 1~6 mm, and the thickness deformation per pass is 1~2.5 mm. (11) The rolled sheet is heated to 490℃~550℃ for solution treatment, held for 0.5~6 h and then quenched to obtain a supersaturated solid solution; (12) Heat the quenched plate to 100℃~200℃ for stress relief annealing, hold for 30~90 min and then let it cool slowly in air to room temperature; (13) After cutting the cooled sheet metal into long strips required for three-dimensional deformation, it is bent in a three-dimensional bending forming mold at a bending temperature of 20~300℃ to obtain parts with shapes that meet the usage requirements, such as Figure 2 As shown, the left figure indicates a workpiece with a width of 16mm, a horizontal bend radius of 15mm, and a bend angle of 90°; the right figure indicates a workpiece with a thickness of 3mm, a vertical bend radius of 3mm, and a bend angle of 90°; the center of the vertical bend and the center of the horizontal bend are 20mm apart.

[0027] (14) Heat the deformed parts to 180℃~220℃ and keep them at that temperature for 4~18 h for aging treatment to improve the conductivity and mechanical properties of the workpiece so that it meets the service conditions of the bus conductor of new energy vehicles and obtain three-dimensional bending high conductivity aluminum alloy parts for the bus conductor of new energy vehicles.

[0028] Furthermore, the flat bending and vertical bending forming mold includes a lower clamping mold 1 and a bending mold 2. The bending mold 2 can be rotated by a power source or manually. The lower part of the lower clamping mold 1 is detachably rotatably connected to the bending mold 2 (preferably rotatably connected to the middle position of the bending mold 2). The upper part of the lower clamping mold 1 consists of two symmetrical clamping blocks, and between the two clamping blocks is a placement groove for placing the plate-shaped straight material 3. The middle part of the plate-shaped straight material 3 is accommodated in the placement groove, and both ends protrude from the placement groove. The width of the placement groove can be adjusted by replacing the lower clamping mold 1 to match the horizontally or vertically placed plate-shaped straight material 3. (Preferably, both the lower clamping mold 1 and the bending mold 2 are disc-shaped and concentrically installed, and the projection of the center line of the placement groove along the length direction onto the upper surface of the bending mold 2 passes through the center of the circle.) A portion is cut off on the same side of the two clamping blocks along the groove width direction, and the cut surface is rounded with the inner wall of the groove. The radius of the rounded corner is the radius to be bent of the plate-shaped straight material 3. The upper surface of the bending die 2 has a protrusion. The shape of the protrusion is not limited, as long as it bends one end of the sheet-like straight material 3 during the rotation of the bending die 2. (In this embodiment, the protrusion is cylindrical.) The bending forming dies for flat and vertical bends in this embodiment are as follows: Figure 3 and Figure 4 As shown, in this embodiment, an upper clamping mold 4 is also installed on the lower clamping mold 1 of the flat bending forming mold. The upper clamping mold 4 is a hollow frustum-shaped structure with an open lower end. The upper clamping mold 4 covers the lower clamping mold 1 inside, and its edges press against the plate-shaped straight strip 3, further preventing the plate-shaped straight strip 3 from shaking during the bending process. The raised rotation trajectory is located on the periphery of the upper clamping mold 4.

[0029] After the robotic arm clamps the sheet-shaped straight material 3 and feeds it into the designated position, the lower clamping mold 1 and the upper clamping mold 4 close to fix the sheet-shaped straight material 3. Then, by rotating the bending mold 2, the sheet-shaped straight material 3 is subjected to a flat bending process with a springback of 2~10°. After the flat bending process is completed, the bending mold 2 returns to the center, and the robotic arm controls the sheet-shaped straight material 3 to be fed forward 20 mm to enter the next station. The robotic arm rotates 90° to make the sheet material fit with the vertical bending mold, and a vertical bending process is performed in the vertical direction of the sheet surface. When the clamping mold 1 of the vertical bending mold clamps the sheet-shaped straight material 3, the bending mold 2 rotates to complete the vertical bending process, with a springback of 2~8°.

[0030] Furthermore, the damage value at the bending point during a flat bending deformation at 20℃ was simulated using finite element method (FEM) simulation. Figure 5 Damage values ​​at the bending point during flat bending deformation at 200℃, such as... Figure 6 Damage values ​​at the bending point during flat bending deformation at 300℃, such as... Figure 7Simulation results show that appropriately increasing the deformation temperature can significantly reduce damage at the bending point during flat bending deformation. Theoretically, the higher the temperature, the smoother the deformation process and the less likely cracks will appear. However, prolonged exposure to high temperatures can lead to a shorter mold life and increased production energy consumption. Therefore, in this embodiment, the bending temperature is set at 200℃ while ensuring deformation quality.

[0031] In addition, in step (5), when the melt temperature is 700℃~740℃ and the rotor speed is 300~500 rpm, argon gas of 0.2~1.0 m is introduced into the melt. 3 / h, chlorine gas 0.02~0.1 m 3 After / h, ensure the hydrogen content in the melt is ≤0.10 ml / 100gAl. In step (8), adjust the cooling water flow rate of the multi-stage strong cold crystallizer in the continuous casting equipment to 20~100 m³ / h. 3 The casting speed is 20~100 mm / min, the casting temperature is 700~740℃, and the liquid level in the crystallizer is 60~150 mm to ensure that the ingot with uniform microstructure is obtained. In step (13), the forming temperature is adjusted to 20~300℃ to ensure that there is no cracking at the bending point of the workpiece after three-dimensional bending deformation.

[0032] The present invention will be described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection and application of the present invention is not limited to the following embodiments.

[0033] Example 1 In this embodiment, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, lanthanum 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0034] In this embodiment, the method for preparing the bus conductor of a new energy vehicle includes the following steps: (1) Prepare alloy raw materials according to the requirements of high conductivity aluminum alloy composition. The alloy raw materials include: pure aluminum (99.7%), Al-12Si master alloy, Al-10Mg master alloy, Al-10La master alloy, refining agent (by mass percentage, 40% sodium cryolite, 46% salt slag for preparing Al-5Ti-1B by fluoride reaction, 10% aluminum fluoride, 2% calcium fluoride, 2% potassium feldspar); (2) Place the pure aluminum ingots into the melting furnace and adjust the melt temperature to 720°C; (3) Add silicon to the melt in the form of Al-12Si master alloy, stir the alloy melt at a speed of 10 rpm, and then keep it at a temperature for 10 min. (4) Reduce the temperature of the alloy melt to 700℃, add magnesium in the form of Al-10Mg master alloy, stir the alloy melt at 10 rpm and keep it at the temperature for 10 min. (5) When the melt temperature is heated to 720℃ and the rotor speed is 300 rpm, a refining agent (500 g / t) and argon gas (0.5 m³ / t) are introduced into the melt. 3 / h), chlorine (0.05 m 3 Purification treatment is carried out at / h); (6) Adjust the above melt temperature to 710℃, add rare earth element La in the form of Al-10La intermediate alloy, stir the alloy melt at a speed of 10 rpm and keep it at the temperature for 10 min to obtain a uniform aluminum alloy melt. (7) Adjust the temperature of the aluminum alloy melt to 730°C so that it enters the crystallizer of the continuous casting device; (8) Construct a multi-stage strong cold crystallizer for continuous casting equipment, and control the casting speed (50 mm / min) and cooling water flow rate (30 m³ / min). 3 / min), number of cooling water injections (15 times), and secondary cooling water temperature (set to room temperature and 60℃ respectively, see Figure 1 The casting temperature is 720℃, the liquid level in the crystallizer is 120 mm, and a uniform ingot with a microstructure is obtained. (9) Heat the aluminum alloy ingot to 475°C and hold for 10 h for homogenization heat treatment; (10) The ingot after homogenization heat treatment is subjected to rolling deformation treatment. The rough rolling temperature is 450℃ and the final rolling temperature is 240℃. The final rolling thickness is 10 mm. There are a total of 17 hot rolling passes with single rolling reductions of 30 mm, 40 mm, 40 mm, 40 mm, 40 mm, 40 mm, 40 mm, 40 mm, 40 mm, 40 mm, 40 mm, 30 mm, 25 mm, 20 mm, 15 mm, and 10 mm. The cold rolling process is carried out at room temperature. The final rolling thickness is 3 mm. There are a total of 4 cold rolling passes with single rolling reductions of 2.5 mm, 2 mm, 1.5 mm, and 1 mm. (11) The rolled sheet was heated to 530°C for solution treatment, and after holding at that temperature for 0.5 h, it was water-quenched to obtain a supersaturated solid solution. (12) Heat the quenched plate to 150°C for stress relief annealing, hold for 60 min and then slowly cool it to room temperature in air. (13) After cutting the cooled sheet metal into strips (3 mm thick, 16 mm wide, and 1000 mm long) for three-dimensional deformation, bend the strips at 200°C in a three-dimensional bending forming mold. After the flat bending and vertical bending processes are completed, cut off the excess length at both ends according to the required allowance to obtain the forming result of the part as shown in the figure. Figure 8 Three parts were prepared according to the method of this embodiment. The surfaces of the three parts were smooth and flat, without obvious cracks. (14) Heat the formed parts to 200°C and keep them at that temperature for 12 hours for aging treatment to improve the conductivity and mechanical properties of the workpiece so that it meets the service conditions of the bus conductor of new energy vehicles and obtain three-dimensional bending high conductivity aluminum alloy parts for the bus conductor of new energy vehicles.

[0035] The three-dimensional bending high-conductivity aluminum alloy material in this embodiment has a tensile strength of 182 MPa, a yield strength of 152 MPa, an elongation of 14%, and an electrical conductivity of 58.85% IACS, as tested according to GB / T 228.1-2021. The prepared three-dimensional bending high-conductivity aluminum alloy parts for busbar conductors in new energy vehicles have uniform and smooth flat and vertical bends without obvious cracks.

[0036] Example 2 In this embodiment, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, lanthanum 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0037] In this embodiment, the method for preparing the bus conductor of a new energy vehicle includes the following steps: (1) Prepare alloy raw materials according to the requirements of high conductivity aluminum alloy composition. The alloy raw materials include: pure aluminum (99.7%), Al-12Si master alloy, Al-10Mg master alloy, Al-10La master alloy, refining agent (by mass percentage, 40% sodium cryolite, 46% salt slag for preparing Al-5Ti-1B by fluoride reaction, 10% aluminum fluoride, 2% calcium fluoride, 2% potassium feldspar); (2) Place the pure aluminum ingots into the melting furnace and adjust the melt temperature to 720°C; (3) Add silicon to the melt in the form of Al-12Si master alloy, stir the alloy melt at a speed of 10 rpm, and then keep it at a temperature for 10 min. (4) Reduce the temperature of the alloy melt to 700℃, add magnesium in the form of Al-10Mg master alloy, stir the alloy melt at 10 rpm and keep it at the temperature for 10 min. (5) When the melt temperature is heated to 720℃ and the rotor speed is 400 rpm, a refining agent and argon gas (0.5 m) are introduced into the melt. 3 / h), chlorine (0.05 m 3 Purification treatment is carried out at / h); (6) Adjust the above melt temperature to 710℃, add rare earth element La in the form of Al-10La intermediate alloy, stir the alloy melt at a speed of 10 rpm and keep it at the temperature for 10 min to obtain a uniform aluminum alloy melt. (7) Adjust the temperature of the aluminum alloy melt to 730°C so that it enters the crystallizer of the continuous casting device; (8) Construct a multi-stage strong cold crystallizer for continuous casting equipment, and control the casting speed (60 mm / min) and cooling water flow rate (40 m³ / min). 3 / min), cooling water spray frequency (15 times) and secondary cooling water temperature (room temperature and 60℃ respectively), casting temperature is 720℃, crystallizer liquid level height is 120 mm, to obtain ingots with uniform microstructure and composition. (9) Heat the aluminum alloy ingot to 475°C and hold for 10 h for homogenization heat treatment; (10) The ingot after homogenization heat treatment is subjected to rolling deformation treatment. The rough rolling temperature of the hot rolling process is 450℃, the final rolling temperature is 240℃, and the final rolling thickness of the plate is 10 mm; the cold rolling process is carried out at room temperature, and the final rolling thickness of the plate is 3 mm. (11) The rolled sheet was heated to 490°C for solution treatment, and after holding at the temperature for 0.5 h, it was water-quenched to obtain a supersaturated solid solution. (12) Heat the quenched plate to 200°C for stress relief annealing, hold for 60 min and then slowly cool it to room temperature in air; (13) After the cooled sheet is cut into strips of sheet shape required for three-dimensional deformation (thickness 3 mm, width 16 mm, length 1000 mm), it is bent in a three-dimensional bending forming mold at 200℃. After the flat bending and vertical bending processes are completed, the excess length at both ends is cut off according to the required allowance, so that the surface of the parts is smooth and flat, without obvious cracks. (14) Heat the formed parts to 210°C and keep them at that temperature for 10 h for aging treatment to improve the conductivity and mechanical properties of the workpiece so that it meets the service conditions of the bus conductor of new energy vehicles and obtain three-dimensional bending high conductivity aluminum alloy parts for the bus conductor of new energy vehicles.

[0038] The three-dimensional bending high-conductivity aluminum alloy material in this embodiment has a tensile strength of 186 MPa, a yield strength of 153 MPa, an elongation of 13%, and an electrical conductivity of 58.24% IACS, as tested according to GB / T 228.1-2021. The prepared three-dimensional bending high-conductivity aluminum alloy parts for new energy vehicle bus conductors have uniform and smooth flat bends without obvious cracks. Compared with Example 1, this embodiment increases the rotor speed in step (5), increases the casting speed and cooling water flow rate in step (8), decreases the solution temperature in step (11), increases the stress-relief annealing temperature in step (12), and increases the aging temperature and reduces the aging time in step (14). The changes in the above process steps increase the alloy strength, but decrease the alloy conductivity and elongation.

[0039] Example 3 In this embodiment, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, lanthanum 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0040] In this embodiment, the method for preparing the bus conductor of a new energy vehicle includes the following steps: (1) Prepare alloy raw materials according to the requirements of high conductivity aluminum alloy composition. The alloy raw materials include: pure aluminum (99.7%), Al-12Si master alloy, Al-10Mg master alloy, Al-10La master alloy, refining agent (by mass percentage, 40% sodium cryolite, 46% salt slag for preparing Al-5Ti-1B by fluoride reaction, 10% aluminum fluoride, 2% calcium fluoride, 2% potassium feldspar); (2) Place the pure aluminum ingots into the melting furnace and adjust the melt temperature to 720°C; (3) Add silicon to the melt in the form of Al-12Si master alloy, stir the alloy melt at a speed of 10 rpm, and then keep it at a temperature for 10 min. (4) Reduce the temperature of the alloy melt to 700℃, add magnesium in the form of Al-10Mg master alloy, stir the alloy melt at 10 rpm and keep it at the temperature for 10 min. (5) When the melt temperature is heated to 720℃ and the rotor speed is 500 rpm, a refining agent (composed of 40% sodium cryolite, 46% salt slag from the reaction of fluoride salts to prepare Al5Ti1B master alloy, 10% aluminum fluoride, 2% calcium fluoride, and 2% potassium feldspar by mass percentage) and argon gas (1.0 m) are introduced into the melt. 3 / h), chlorine (0.1 m 3 Purification treatment is carried out at / h); (6) Adjust the above melt temperature to 710℃, add rare earth element La in the form of Al-10La intermediate alloy, stir the alloy melt at a speed of 10 rpm and keep it at the temperature for 10 min to obtain a uniform aluminum alloy melt. (7) Adjust the temperature of the aluminum alloy melt to 730°C so that it enters the crystallizer of the continuous casting device; (8) Construct a multi-stage strong cold crystallizer for continuous casting equipment, and control the casting speed (100 mm / min) and the cooling water flow rate (50 m³ / min). 3 / min), cooling water spray frequency (15 times) and secondary cooling water temperature (room temperature and 60℃ respectively), casting temperature is 720℃, crystallizer liquid level height is 120 mm, to obtain ingots with uniform microstructure and composition. (9) Heat the aluminum alloy ingot to 475°C and hold for 10 h for homogenization heat treatment; (10) The ingot after homogenization heat treatment is subjected to rolling deformation treatment. The rough rolling temperature of the hot rolling process is 450℃, the final rolling temperature is 240℃, and the final rolling thickness of the plate is 10 mm; the cold rolling process is carried out at room temperature, and the final rolling thickness of the plate is 3 mm. (11) The rolled plate was heated to 510°C for solution treatment, and after holding at the temperature for 0.5 h, it was water-quenched to obtain a supersaturated solid solution. (12) Heat the quenched plate to 200°C for stress relief annealing, hold for 60 min and then slowly cool it to room temperature in air; (13) After the cooled sheet is cut into strips of sheet shape required for three-dimensional deformation (thickness 3 mm, width 16 mm, length 1000 mm), it is bent in a three-dimensional bending forming mold at 200℃. After the flat bending and vertical bending processes are completed, the excess length at both ends is cut off according to the required allowance, so that the surface of the parts is smooth and flat, without obvious cracks. (14) Heat the formed parts to 210°C and keep them at that temperature for 10 h for aging treatment to improve the conductivity and mechanical properties of the workpiece so that it meets the service conditions of the bus conductor of new energy vehicles and obtain three-dimensional bending high conductivity aluminum alloy parts for the bus conductor of new energy vehicles.

[0041] The three-dimensional bending high-conductivity aluminum alloy material in this embodiment has a tensile strength of 188 MPa, a yield strength of 157 MPa, an elongation of 12.5%, and an electrical conductivity of 58.78% IACS, as tested according to GB / T 228.1-2021. The prepared three-dimensional bending high-conductivity aluminum alloy parts for new energy vehicle bus conductors have uniform and smooth flat bends without obvious cracks. Compared with Example 2, this embodiment increases the rotor speed and the flow rate of argon and chlorine in step (5), increases the casting speed and cooling water flow rate in step (8), and increases the solution temperature in step (11). The changes in the above process steps slightly reduce the elongation, but improve the alloy strength and conductivity.

[0042] Example 4 In this embodiment, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, cerium 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0043] In this embodiment, the method for preparing the bus conductor of a new energy vehicle includes the following steps: (1) Prepare alloy raw materials according to the requirements of high conductivity aluminum alloy composition. The alloy raw materials include: pure aluminum (99.7%), Al-12Si master alloy, Al-10Mg master alloy, Al-10Ce master alloy, and refining agent (by mass percentage, 40% sodium cryolite, 46% salt slag for preparing Al-5Ti-1B by fluoride reaction, 10% aluminum fluoride, 2% calcium fluoride, and 2% potassium feldspar). (2) Place the pure aluminum ingots into the melting furnace and adjust the melt temperature to 720°C; (3) Add silicon to the melt in the form of Al-12Si master alloy, stir the alloy melt at a speed of 10 rpm, and then keep it at a temperature for 10 min. (4) Reduce the temperature of the alloy melt to 700℃, add magnesium in the form of Al-10Mg master alloy, stir the alloy melt at 10 rpm and keep it at the temperature for 10 min. (5) When the melt temperature is heated to 720℃ and the rotor speed is 300 rpm, a refining agent and argon gas (0.5 m) are introduced into the melt. 3 / h), chlorine (0.05 m 3 Purification treatment is carried out at / h); (6) Adjust the above melt temperature to 710℃, add rare earth element Ce in the form of Al-10Ce master alloy, stir the alloy melt at a speed of 10 rpm and keep it at the temperature for 10 min to obtain a uniform aluminum alloy melt. (7) Adjust the temperature of the aluminum alloy melt to 730°C so that it enters the crystallizer of the continuous casting device; (8) Construct a multi-stage strong cold crystallizer for continuous casting equipment, and control the casting speed (50 mm / min) and cooling water flow rate (30 m³ / min). 3 / min), number of cooling water injections (15 times), and secondary cooling water temperature (set to room temperature and 60℃ respectively, see Figure 1 The casting temperature is 720℃, the liquid level in the crystallizer is 120 mm, and a uniform ingot with a microstructure is obtained. (9) Heat the aluminum alloy ingot to 475°C and hold for 10 h for homogenization heat treatment; (10) The ingot after homogenization heat treatment is subjected to rolling deformation treatment. The rough rolling temperature of the hot rolling process is 450℃, the final rolling temperature is 240℃, and the final rolling thickness of the plate is 10 mm; the cold rolling process is carried out at room temperature, and the final rolling thickness of the plate is 3 mm. (11) The rolled sheet was heated to 530°C for solution treatment, and after holding at that temperature for 0.5 h, it was water-quenched to obtain a supersaturated solid solution. (12) Heat the quenched plate to 150°C for stress relief annealing, hold for 60 min and then slowly cool it to room temperature in air. (13) After the cooled sheet is cut into strips of sheet shape required for three-dimensional deformation (thickness 3 mm, width 16 mm, length 1000 mm), it is bent in a three-dimensional bending forming mold at 200℃. After the flat bending and vertical bending processes are completed, the excess length at both ends is cut off according to the required allowance, so that the surface of the parts is smooth and flat, without obvious cracks. (14) Heat the formed parts to 200°C and keep them at that temperature for 12 hours for aging treatment to improve the conductivity and mechanical properties of the workpiece so that it meets the service conditions of the bus conductor of new energy vehicles and obtain three-dimensional bending high conductivity aluminum alloy parts for the bus conductor of new energy vehicles.

[0044] The three-dimensional bending high-conductivity aluminum alloy material in this embodiment has a tensile strength of 178 MPa, a yield strength of 145 MPa, an elongation of 12.5%, and an electrical conductivity of 58.88% IACS, as tested according to GB / T 228.1-2021. The prepared three-dimensional bending high-conductivity aluminum alloy parts for new energy vehicle busbar conductors have uniform and smooth bends without obvious cracks. Compared with Example 1, this embodiment uses the rare earth element cerium to replace the addition of lanthanum, resulting in a smaller change in the alloy's conductivity, but a slight decrease in strength and elongation.

[0045] Example 5 In this embodiment, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, cerium 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0046] In this embodiment, the method for preparing the bus conductor of a new energy vehicle includes the following steps: (1) Prepare alloy raw materials according to the requirements of high conductivity aluminum alloy composition. The alloy raw materials include: pure aluminum (99.7%), Al-12Si master alloy, Al-10Mg master alloy, Al-10Ce master alloy, and refining agent (by mass percentage, 40% sodium cryolite, 46% salt slag for preparing Al-5Ti-1B by fluoride reaction, 10% aluminum fluoride, 2% calcium fluoride, and 2% potassium feldspar). (2) Place the pure aluminum ingots into the melting furnace and adjust the melt temperature to 720°C; (3) Add silicon to the melt in the form of Al-12Si master alloy, stir the alloy melt at a speed of 10 rpm, and then keep it at a temperature for 10 min. (4) Reduce the temperature of the alloy melt to 700℃, add magnesium in the form of Al-10Mg master alloy, stir the alloy melt at 10 rpm and keep it at the temperature for 10 min. (5) When the melt temperature is heated to 720℃ and the rotor speed is 400 rpm, a refining agent and argon gas (0.5 m) are introduced into the melt. 3 / h), chlorine (0.05 m 3 Purification treatment is carried out at / h); (6) Adjust the above melt temperature to 710℃, add rare earth element Ce in the form of Al-10Ce master alloy, stir the alloy melt at a speed of 10 rpm and keep it at the temperature for 10 min to obtain a uniform aluminum alloy melt. (7) Adjust the temperature of the aluminum alloy melt to 730°C so that it enters the crystallizer of the continuous casting device; (8) Construct a multi-stage strong cold crystallizer for continuous casting equipment, and control the casting speed (60 mm / min) and cooling water flow rate (40 m³ / min). 3 / min), cooling water spray frequency (15 times) and secondary cooling water temperature (room temperature and 60℃ respectively), casting temperature is 720℃, crystallizer liquid level height is 120 mm, to obtain ingots with uniform microstructure and composition. (9) Heat the aluminum alloy ingot to 475°C and hold for 10 h for homogenization heat treatment; (10) The ingot after homogenization heat treatment is subjected to rolling deformation treatment. The rough rolling temperature of the hot rolling process is 450℃, the final rolling temperature is 240℃, and the final rolling thickness of the plate is 10 mm; the cold rolling process is carried out at room temperature, and the final rolling thickness of the plate is 3 mm. (11) The rolled sheet was heated to 490°C for solution treatment, and after holding at the temperature for 0.5 h, it was water-quenched to obtain a supersaturated solid solution. (12) Heat the quenched plate to 200°C for stress relief annealing, hold for 60 min and then slowly cool it to room temperature in air; (13) After the cooled sheet is cut into strips of sheet shape required for three-dimensional deformation (thickness 3 mm, width 16 mm, length 1000 mm), it is bent in a three-dimensional bending forming mold at 200℃. After the flat bending and vertical bending processes are completed, the excess length at both ends is cut off according to the required allowance, so that the surface of the parts is smooth and flat, without obvious cracks. (14) Heat the formed parts to 210°C and keep them at that temperature for 13 hours for aging treatment to improve the conductivity and mechanical properties of the workpiece so that it meets the service conditions of the bus conductor of new energy vehicles and obtain three-dimensional bending high conductivity aluminum alloy parts for the bus conductor of new energy vehicles.

[0047] The three-dimensional bending high-conductivity aluminum alloy material in this embodiment has a tensile strength of 174 MPa, a yield strength of 143 MPa, an elongation of 13.5%, and an electrical conductivity of 58.42% IACS, as tested according to GB / T 228.1-2021. The prepared three-dimensional bending high-conductivity aluminum alloy parts for new energy vehicle bus conductors have uniform and smooth flat bends without obvious cracks. Compared with Example 4, this embodiment increases the rotor speed in step (5), increases the casting speed and cooling water flow rate in step (8), decreases the solution temperature in step (11), increases the stress-relief annealing temperature in step (12), and increases the aging temperature and aging time in step (14). The changes in the above process steps increase the alloy elongation, but decrease the alloy conductivity and strength.

[0048] Example 6 In this embodiment, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, cerium 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0049] In this embodiment, the method for preparing the bus conductor of a new energy vehicle includes the following steps: (1) Prepare alloy raw materials according to the requirements of high conductivity aluminum alloy composition. The alloy raw materials include: pure aluminum (99.7%), Al-12Si master alloy, Al-10Mg master alloy, Al-10Ce master alloy, and refining agent (by mass percentage, 40% sodium cryolite, 46% salt slag for preparing Al-5Ti-1B by fluoride reaction, 10% aluminum fluoride, 2% calcium fluoride, and 2% potassium feldspar). (2) Place the pure aluminum ingots into the melting furnace and adjust the melt temperature to 720°C; (3) Add silicon to the melt in the form of Al-Si master alloy, stir the alloy melt at a speed of 10 rpm, and then keep it at a temperature for 10 min. (4) Reduce the temperature of the alloy melt to 700℃, add magnesium in the form of Al-Mg master alloy, stir the alloy melt at 10 rpm and keep it at the temperature for 10 min. (5) When the melt temperature is heated to 720℃ and the rotor speed is 500 rpm, a refining agent (composed of 40% sodium cryolite, 46% salt slag from the reaction of fluoride salts to prepare Al5Ti1B master alloy, 10% aluminum fluoride, 2% calcium fluoride, and 2% potassium feldspar by mass percentage) and argon gas (1.0 m) are introduced into the melt. 3 / h), chlorine (0.1 m 3 Purification treatment is carried out at / h); (6) Adjust the above melt temperature to 710℃, add rare earth element Ce in the form of Al-10Ce master alloy, stir the alloy melt at a speed of 10 rpm and keep it at the temperature for 10 min to obtain a uniform aluminum alloy melt. (7) Adjust the temperature of the aluminum alloy melt to 730°C so that it enters the crystallizer of the continuous casting device; (8) Construct a multi-stage strong cold crystallizer for continuous casting equipment, and control the casting speed (100 mm / min) and the cooling water flow rate (50 m³ / min). 3 / min), cooling water spray frequency (15 times) and secondary cooling water temperature (room temperature and 60℃ respectively), casting temperature is 720℃, crystallizer liquid level height is 120 mm, to obtain ingots with uniform microstructure and composition. (9) Heat the aluminum alloy ingot to 475°C and hold for 10 h for homogenization heat treatment; (10) The ingot after homogenization heat treatment is subjected to rolling deformation treatment. The rough rolling temperature of the hot rolling process is 450℃, the final rolling temperature is 240℃, and the final rolling thickness of the plate is 10 mm; the cold rolling process is carried out at room temperature, and the final rolling thickness of the plate is 3 mm. (11) The rolled plate was heated to 510°C for solution treatment, and after holding at the temperature for 0.5 h, it was water-quenched to obtain a supersaturated solid solution. (12) Heat the quenched plate to 200°C for stress relief annealing, hold for 60 min and then slowly cool it to room temperature in air; (13) After the cooled sheet is cut into strips of sheet shape required for three-dimensional deformation (thickness 3 mm, width 16 mm, length 1000 mm), it is bent in a three-dimensional bending forming mold at 200℃ to obtain parts with smooth and flat surfaces and no obvious cracks. (14) Heat the formed parts to 210°C and keep them at that temperature for 16 hours for aging treatment to improve the conductivity and mechanical properties of the workpiece so that it meets the service conditions of the bus conductor of new energy vehicles and obtain three-dimensional bending high conductivity aluminum alloy parts for the bus conductor of new energy vehicles.

[0050] The three-dimensional bending high-conductivity aluminum alloy material in this embodiment has a tensile strength of 177 MPa, a yield strength of 145 MPa, an elongation of 12.5%, and an electrical conductivity of 58.52% IACS, as tested according to GB / T 228.1-2021. The prepared three-dimensional bending high-conductivity aluminum alloy parts for new energy vehicle bus conductors have uniform and smooth flat bends without obvious cracks. Compared with Example 5, this embodiment increases the rotor speed and the flow rate of argon and chlorine in step (5), increases the casting speed and cooling water flow rate in step (8), increases the solution temperature in step (11), and increases the aging time in step (14). The changes in the above process steps improve the alloy strength and conductivity, but reduce the elongation.

[0051] Comparative Example 1 In this comparative example, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, lanthanum 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0052] The processing method of this comparative example is the same as that of Example 1, except that: The temperature of the three-dimensional bending deformation in step (13) is room temperature.

[0053] This comparative example, a highly conductive aluminum alloy material subjected to three-dimensional bending, exhibits a tensile strength of 180 MPa, a yield strength of 150 MPa, an elongation of 14%, and an electrical conductivity of 58.78% IACS, as tested according to GB / T 228.1-2021. Compared to Example 1, this comparative example 1 underwent three-dimensional bending deformation at room temperature, as shown... Figure 9As shown, the three-dimensional bending high-conductivity aluminum alloy component for busbar conductors of new energy vehicles prepared in this comparative example is comparable to that of Example 1 in terms of material performance testing. However, due to the low bending temperature, it fails at the flat bend and cannot be used.

[0054] Comparative Example 2 In this comparative example, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, lanthanum 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0055] The processing method of this comparative example is the same as that of Example 1, except that: In step (5), when the melt temperature is heated to 720°C and the rotor speed is 100 rpm, only argon gas (0.1 m³ / min) is introduced. 3 / h), chlorine (0.01 m 3 Purification treatment is carried out ( / h).

[0056] The comparative example of a three-dimensional bending high-conductivity aluminum alloy material, tested according to GB / T 228.1-2021, has a tensile strength of 157 MPa, a yield strength of 122 MPa, an elongation of 10.5%, and an electrical conductivity of 56.26% IACS. Compared with Examples 1-6, Comparative Example 2 did not contain a refining agent, and the flow rates of argon and chlorine were relatively low, resulting in a weakened degassing and slag removal effect on the alloy, and obvious inclusions appeared inside the alloy, such as... Figure 10 This ultimately leads to a significant decrease in the alloy's properties.

[0057] Comparative Example 3 In this comparative example, the composition of the three-dimensional bending high conductivity aluminum alloy used for the bus conductor of new energy vehicles, by mass percentage, is: iron 0.1%, magnesium 0.6%, silicon 0.35%, lanthanum 0.1%, titanium ≤0.05%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.05%, zinc ≤0.1%, with the balance being aluminum.

[0058] The processing method of this comparative example is the same as that of Example 1, except that: In step (8), the cooling water flow rate is 100 m³ / s. 3 The cooling water spray rate was 30 times per minute, and the cooling water temperature in the crystallizer was room temperature.

[0059] Compared with Examples 1-6, Comparative Example 3 used a lower temperature and a higher flow rate of cooling water to cool the ingot more intensely. During the cooling process, the casting stress was too high, and small cracks appeared on the surface of the ingot produced under this process, such as... Figure 11This does not meet the requirements for material production and use.

[0060] The results show that this invention innovatively proposes a complete process and chain preparation method for three-dimensional bending high-conductivity aluminum alloy materials used in new energy vehicle busbar conductors. By adding refining agents and rare earth elements, and effectively using argon and chlorine gas to degas and remove slag from the alloy melt, a multi-stage high-intensity cold crystallizer continuous casting process was used to obtain ingots with uniform microstructure and composition. Furthermore, by controlling the process flow and optimizing parameters during production, a high-conductivity aluminum alloy material suitable for large-scale production was obtained. Through optimized control of the deformation process, three-dimensional bending high-conductivity aluminum alloy components for new energy vehicle busbar conductors were finally prepared, exhibiting a tensile strength of 182 MPa, a yield strength of 152 MPa, an elongation of 14%, and an electrical conductivity of 58.2% IACS, meeting the acceptance criteria.

[0061] The component manufacturing method involved in this invention can be extended to the field of manufacturing aluminum alloy parts with complex shapes and large deformation, effectively solving the problem of component cracking caused by large deformation, while reducing production costs.

Claims

1. A high-conductivity aluminum alloy material for busbar conductors in new energy vehicles, characterized in that, By mass percentage, the composition is: aluminum 97.22~99.35%, magnesium 0.35~0.8%, silicon 0.3~0.7%, iron ≤0.5%, lanthanum or cerium 0.05~0.3%, titanium ≤0.1%, manganese ≤0.03%, chromium ≤0.03%, copper ≤0.1%, boron ≤0.06%, and zinc ≤0.1%.

2. A method for preparing a busbar conductor for a new energy vehicle, characterized in that, Includes the following steps: (1) According to the composition of the aluminum alloy material described in claim 1, take the alloy raw materials for smelting, add Al, Si and Mg elements in sequence during the smelting process, purify the material, add rare earth elements and continue smelting to obtain the alloy melt. (2) The above alloy melt is subjected to directional solidification casting using a multi-stage strong cooling process, and the cooling rate during the solidification process is controlled to obtain an ingot. (3) The ingot is subjected to homogenization heat treatment, rolling deformation treatment, solution treatment and quenching in sequence to obtain supersaturated solid solution plate material; (4) After stress-relief annealing, the above sheet material is subjected to three-dimensional bending and forming; (5) The formed parts are subjected to aging treatment to obtain a three-dimensional bending busbar conductor for new energy vehicles.

3. The method for preparing the busbar conductor of a new energy vehicle according to claim 2, characterized in that, In step (1), the raw materials provided for Al, Si, Mg and rare earth elements are: pure aluminum ingot, Al-Si master alloy, Al-Mg master alloy and Al-rare earth master alloy; the rare earth elements are La or Ce. The pure aluminum ingot is smelted at 700℃~740℃; after adding Si, it is smelted at 700℃~740℃ for 10-30 minutes; the temperature is adjusted to 690℃~710℃, Mg is added, and the temperature is maintained for 10-30 minutes; the temperature is adjusted to 700℃~720℃, rare earth elements are added, and the mixture is stirred and allowed to stand for 10-30 minutes.

4. The method for preparing the bus conductor of a new energy vehicle according to claim 2, characterized in that, In step (1), the purification process involves introducing a refining agent, argon, and chlorine into the melt. The refining agent, by mass percentage, consists of 40% sodium cryolite, 46% salt slag from the reaction of fluoride salts to prepare the Al-5Ti-1B master alloy, 10% aluminum fluoride, 2% calcium fluoride, and 2% potassium feldspar.

5. The method for preparing the bus conductor of a new energy vehicle according to claim 4, characterized in that, In step (1), the purification process involves introducing 0.2 to 1.0 m³ of argon gas into the melt at a melt temperature of 700℃~740℃ and a rotor speed of 300~500 rpm. 3 / h, chlorine gas 0.02~0.1 m 3 / h and refining agent 400~600 g / t, so that the hydrogen content in the melt is ≤0.10 ml / 100gAl.

6. The method for preparing a new energy vehicle busbar conductor according to claim 2, characterized in that, In step (2), the temperature of directional solidification is 720℃~740℃, and the cooling rate is adjusted by regulating the cooling water flow rate of the multi-stage strong refrigeration crystallizer to 20~100 m³ / h. 3 The process is achieved by using a casting speed of 20-100 mm / min, a temperature of 20-100℃, a casting speed of 20-100 mm / min, 15-25 cooling water sprays, and a liquid level height of 60-150 mm in the crystallizer.

7. The method for preparing a busbar conductor for a new energy vehicle according to claim 2, characterized in that, In step (3), the homogenization heat treatment temperature is 460℃~490℃, and the holding time is 8~16 h; The rolling deformation treatment includes hot rolling and cold rolling. The roughing temperature of the hot rolling treatment is 400~500℃, the finishing temperature is 200~300℃, the final rolling thickness of the rolled plate is 6~10 mm, and the thickness deformation per pass is 10~40 mm. The cold rolling treatment is carried out at room temperature, the final rolling thickness of the rolled plate is 1~6 mm, and the thickness deformation per pass is 1~2.5 mm. The solution treatment temperature is 490℃~550℃, and the holding time is 1~6 h; The quenching condition is water quenching.

8. The method for preparing the bus conductor of a new energy vehicle according to claim 2, characterized in that, In step (4), the stress-relief annealing temperature is 100℃~200℃, the holding time is 30~90 min, and after holding, it is air-cooled to room temperature; the three-dimensional bending forming temperature is 100~300°.

9. The method for preparing a busbar conductor for a new energy vehicle according to claim 2, characterized in that, In step (4), the tooling for three-dimensional bending is a bending forming mold, which includes a lower clamping mold (1) and a bending mold (2). The bending mold (2) can be rotated by a power source or manually. The lower part of the lower clamping mold (1) is detachably rotatably connected to the bending mold (2). The upper part of the lower clamping mold (1) consists of two symmetrical clamping blocks. Between the two clamping blocks is a placement groove for placing a plate-shaped straight strip (3). The middle part of the plate-shaped straight strip (3) is accommodated in the placement groove, and the two ends are respectively It passes through the placement groove; the width of the placement groove can be adjusted by changing the lower clamping mold (1) to match the horizontally or vertically placed plate-shaped straight strip (3); a part is cut off on the same side of the two clamping blocks along the groove width direction, and the cut surface and the inner wall of the groove are rounded. The radius of the rounded corner is the radius to be bent of the plate-shaped straight strip (3); a protrusion is provided on the upper surface of the bending mold (2). The shape of the protrusion is not limited. As long as one end of the plate-shaped straight strip (3) is bent during the rotation of the bending mold (2); The specific process of the three-dimensional bending forming is as follows: After the sheet material is cut into a certain width of sheet-shaped straight strip (3), it enters the lower clamping mold (1). The bending mold (2) rotates 90° to perform a flat bending process on the sheet-shaped straight strip (3), with a springback of 2~10°. After the flat bending process is completed, the bending mold (2) returns to the center, and the sheet-shaped straight strip (3) is automatically fed forward 20-30cm to perform the next stage of vertical bending process. The lower clamping mold (1) of the vertical bending mold is controlled by the robotic arm to clamp the sheet material, and then the bending mold (2) rotates 90° to complete the vertical bending process. The springback of the vertical bending process is 2~8°.

10. The method for preparing a busbar conductor for a new energy vehicle according to claim 2, characterized in that, In step (5), the aging treatment temperature is 180℃~220℃ and the heat preservation time is 8~25 h.

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