Forming die and forming process for copper-aluminum composite bus

Abstract

The application provides a forming die and forming process of copper-aluminum composite row, the forming die comprises a material ejecting rod (1), a lower die (2), a pressure ring (5) and an oil injection port (6); the lower die (2) is a support structure with a square groove in the center of the upper surface and a through hole in the center of the square groove; the material ejecting rod (1) is arranged in the through hole in the center of the square groove of the lower die (2) and can move up and down in the through hole; the pressure ring (5) is arranged on the upper part of the square groove of the lower die (2) and is fixedly connected with the edge of the square groove of the lower die (2) and the plate type copper-aluminum composite row (4) to keep the pressure tight during the forming process of the plate type copper-aluminum composite row (4); the oil injection port (6) is arranged in the center of the pressure ring (5) and is used for injecting flexible medium onto the upper surface of the plate type copper-aluminum composite row (4) to form a shaping pressure on the upper surface of the plate type copper-aluminum composite row (4). The forming die of the application realizes one-time pressure forming of the copper-aluminum composite row through the flexible medium, and the pressure is uniform, and the conductivity and the interface strength do not change obviously.

Description

Technical Field

[0001] This invention relates generally to the field of metal wire composite technology, and specifically to a molding die and molding process for a copper-aluminum composite busbar. Background Technology

[0002] With the rapid development of my country's power and electrical technology, especially the increasing use of new energy vehicles and high-voltage, high-current equipment, the demand for connection materials (busbars) between application equipment and power input is growing, and the requirements for their cost and energy efficiency are also becoming increasingly stringent.

[0003] Currently, the most commonly used busbars are still copper and aluminum. Copper busbars have good conductivity but are too expensive. Although aluminum busbars are cheaper than copper busbars, their conductivity is poor, especially at the connection points. Because aluminum is very easy to oxidize, it increases contact resistance and degrades electrical performance.

[0004] Copper-aluminum composite busbars are a new type of conductor material that combines the high-quality, stable conductivity of copper with the low cost of aluminum, resulting in a low contact resistance. This is of great significance for reducing equipment costs and weight.

[0005] Currently, the main manufacturing processes for copper-aluminum composite panels include rolling composite, explosive composite, and diffusion welding, which can achieve high-quality, low-cost, and high-efficiency production. Among these, the rolling composite method is the most commonly used. The resulting copper-aluminum rolled composite material not only possesses the advantages of copper, such as high conductivity and low contact resistance, but also the characteristics of aluminum, such as light weight, corrosion resistance, and good economic efficiency. It has wide applications in the fields of power, electronics, electrical engineering, and information technology.

[0006] The current trend towards integration and lightweighting in power equipment and new energy vehicles means that simple plate-shaped copper-aluminum composite bars can no longer meet practical application requirements. However, complex-shaped copper-aluminum composite bars place higher demands on subsequent forming technologies, such as the coordinated deformation control of the two materials (copper and aluminum) and the control of interface evolution during deformation. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a forming mold for copper-aluminum composite bars in response to the requirements of lightweight and integrated electrical equipment and new energy vehicles. It is based on flexible medium forming and performs subsequent plastic deformation processes such as bending and extrusion on existing simple plate-shaped copper-aluminum composite bars that are rolled and composite, so as to facilitate their practical application in a convenient and economical way. It can also provide a complete process to process more suitable plate-shaped copper-aluminum composite bars as needed.

[0008] Therefore, this invention provides a forming mold and forming process for copper-aluminum composite bars. The core of the process lies in using a flexible medium to transmit pressure, transforming the plate-shaped copper-aluminum composite bar into the desired irregular structure. The forming mold uses a steel mold as the lower mold and a liquid or inert gas as the force transmission medium to complete the bending and extrusion forming of the copper-aluminum composite bar. The method of this invention also includes a process of forming a plate-shaped copper-aluminum composite bar from aluminum and copper materials through processes such as melting, rolling, and composite rolling, and then obtaining the copper-aluminum composite bar through the forming mold. The mold and method of this invention are significantly simplified, reducing production costs. The flexible medium eliminates stress concentration, resulting in uniform material deformation and excellent performance.

[0009] To achieve the above objectives, this invention designs a rigid mold and a blank holder required for flexible forming technology, selects a flexible pressure transmission medium, and studies and optimizes various process parameters, such as blank holder force and hydraulic strength, based on the provided forming mold. Ultimately, it realizes a method for high-precision one-time preparation of copper-aluminum composite bars of various shapes while ensuring the quality of the copper-aluminum interface.

[0010] The technical solution of this invention is: a forming mold for a copper-aluminum composite busbar, comprising an ejector rod, a lower mold, a pressure ring, and an oil injection port; the lower mold is a support structure with a square groove in the center of its upper surface and a through hole in the center of the square groove; the ejector rod is disposed in the through hole in the center of the square groove of the lower mold and can move up and down controllably within the through hole; the pressure ring is disposed on the upper part of the square groove of the lower mold and is fixedly connected and pressed with the edge of the square groove of the lower mold and the plate copper-aluminum composite busbar during the plate copper-aluminum composite busbar forming process; the oil injection port is disposed in the center of the pressure ring and is used to inject a flexible medium into the upper surface of the plate copper-aluminum composite busbar to form a plastic forming pressure on the upper surface of the plate copper-aluminum composite busbar.

[0011] Furthermore, the edges of the square groove opening and the center through hole opening of the lower mold are rounded; the flexible medium is a liquid medium.

[0012] Furthermore, the rounded corner radius of the square groove edge of the lower mold is 20%-50% of the thickness of the plate copper-aluminum composite strip; the material of the lower mold is Cr12 alloy tool steel; the material of the pressure ring is 40Cr special steel; the pressure ring is locked to the edge of the square groove of the lower mold and the plate copper-aluminum composite strip between them by bolts, and is pressed by the pressure head of the hydraulic press according to the preset pressure force; the liquid medium is hydraulic oil, which is injected into the injection port by the hydraulic press.

[0013] This invention also provides a forming process for a copper-aluminum composite busbar, which uses the forming mold for the copper-aluminum composite busbar provided above, and includes the following steps:

[0014] S1. Raw materials and preparation of copper-aluminum composite busbar: Industrial pure copper and electrical aluminum are selected as precursors for copper-aluminum composite busbar. The aluminum is obtained by melting electrical aluminum to obtain molten aluminum, and then composite casting and rolling with rolled copper coil to obtain plate copper-aluminum composite busbar.

[0015] S2. After ultrasonic cleaning of the surface of the plate copper-aluminum composite busbar obtained in step S1, place it on the lower mold of the forming mold of the copper-aluminum composite busbar, then cover it with the pressure ring and lock it, and press it according to the preset pressure force. Then reset the ejector rod to the plane of the square groove of the lower mold or even below the bottom plane of the square groove, and inject flexible medium into the upper surface of the plate copper-aluminum composite busbar through the oil injection hole.

[0016] S3. The plate-type copper-aluminum composite busbar is pressure-shaped by a flexible medium injected through the oil injection hole.

[0017] S4. After the plate copper-aluminum composite busbar is formed by the pressure generated by the flexible medium, the pressure in the oil injection hole is first released, then the pressure of the hydraulic press head acting on the pressure ring is released, and finally the formed copper-aluminum composite busbar is ejected by moving the ejector rod.

[0018] S5. After the formed copper-aluminum composite busbar is ultrasonically cleaned by immersion in acetone, it undergoes stress annealing treatment.

[0019] Furthermore, in step S1 above, the industrial pure copper is industrial pure copper TU1; the electrical aluminum is electrical aluminum 1050.

[0020] The rolling system includes the following structure: a degassing box, a filter box, a liquid level control system 10), a casting nozzle, and a casting roll, which are connected in sequence. The degassing box is used to remove gas; the filter box is used to filter impurities; the liquid level control system is used to control the flow rate and liquid level of the aluminum liquid; the casting nozzle is used to spray out the aluminum liquid; and the casting roll is used to wind the copper coils rolled from industrial pure copper TU1 and the aluminum liquid.

[0021] The specific process is as follows: molten electrical aluminum is obtained, and the aluminum is kept at 800-1200℃ and degassed in a degassing box. After passing through a filter box, it continues to pass through a liquid level control system and a casting nozzle in sequence, and is composite cast and rolled with industrial pure copper coils pre-wound on casting rolls. Then, after heat treatment and annealing processes, a plate-shaped copper-aluminum composite busbar is obtained. It is then thinned by alternating hot rolling and cold rolling to obtain a plate-shaped copper-aluminum composite busbar.

[0022] Furthermore, in the above-mentioned step S1 process: the parameters for rolling molten aluminum and industrial pure copper coils are as follows: the rolling speed is 800-1200 mm / min, the rolling is driven by a hydraulic press, the hydraulic press cylinder pressure is 20 tons, and the height difference between the molten aluminum surface and the injection nozzle is adjusted to 20 mm through the liquid level control system; the resulting plate-shaped copper-aluminum composite bar initial product has a thickness of 20 mm and a width of 710 mm; the resulting plate-shaped copper-aluminum composite bar initial product then undergoes multiple stages of hot rolling and cold rolling to achieve a thinning amount of 50%.

[0023] Furthermore, the heat treatment and annealing process in step S1 above includes: heat treatment method is quenching, temperature is 550℃, holding time is 4 hours; annealing temperature is 350℃, time is 3 hours.

[0024] Furthermore, in step S2 above, the pre-set blank holder force is 1.1 tons; in step S4, the pressure generated by the flexible medium is achieved through a hydraulic press; the hydraulic press is a YQ32-315 type 100-ton four-column vertical hydraulic press from Zhongyou Heavy Industry; after the oil pump of the hydraulic press starts working, it goes through three stages of pressure increase, pressure holding, and pressure reduction, and the flexible medium performs pressure plasticization on the copper-aluminum composite strip to be formed.

[0025] Furthermore, in step S4 above, the pressure mechanism applied by the hydraulic press to the flexible medium is as follows: the pressure is increased to 30MPa at a constant speed within 0-30 seconds, the pressure is maintained at this pressure for 1 minute, and then the pressure is released within 30 seconds.

[0026] Furthermore, in step S5 above, the annealing process is carried out in a vacuum tube furnace, and high-purity argon gas is continuously introduced as a protective gas during the annealing process. The annealing temperature is 350°C and the time is 3 hours.

[0027] The advantage of this invention over the prior art lies in:

[0028] (1) The forming mold of the copper-aluminum composite bar of the present invention: A square groove is designed in the middle of the upper surface of the lower mold. The height difference between the top and bottom of the square groove serves as the first plastic deformation space of the plate-shaped copper-aluminum composite bar. When the pressure ring, the plate-shaped copper-aluminum composite bar and the edge of the square groove of the lower mold are fixed and pressed together, the pressure of the flexible medium injected by the oil injection port causes the plate-shaped copper-aluminum composite bar to be deformed downward along the square groove until the plate-shaped copper-aluminum composite bar is in contact with the wall of the square groove. The ejector rod plays the role of ejecting the copper-aluminum composite bar from the square groove of the lower mold after the plastic molding and demolding are completed. On the other hand, according to the position of the ejector rod in the square groove, it can provide a second plastic deformation space for the plate-shaped copper-aluminum composite bar at the same time. For example, when the ejector rod is at a certain height below or above the through hole at the bottom of the square groove, the height difference between the top of the ejector rod and the bottom of the square groove will cause the plate-shaped copper-aluminum composite bar to undergo a second plastic deformation due to the change of the internal structure of the lower mold (of course, when the top of the ejector rod is flush with the top of the square groove, the plate-shaped copper-aluminum composite bar will not undergo a second deformation).

[0029] (2) The molding die of the copper-aluminum composite bar of the present invention innovatively uses liquid as a flexible force transmission medium to shape the plate copper-aluminum composite bar under pressure; the sealing, fastening and pressure resistance of the pressure ring, the plate copper-aluminum composite bar and the lower die are achieved by the pressure ring and bolt locking made of 40Cr special steel material, and the hydraulic press head pre-pressing.

[0030] (3) The forming mold of the copper-aluminum composite busbar of the present invention is designed with a suitable arc deformation transition angle, so that the rounded transition of the plate copper-aluminum composite busbar is more easily subjected to the action of flexible medium and naturally deformed during the forming process, without sharp corners and the resulting changes in conductivity and interface strength, resulting in products with high precision and good surface finish.

[0031] (4) The forming mold of the copper-aluminum composite strip of the present invention can ensure the mold life by selecting a suitable mold material and effectively improve the surface quality of the copper-aluminum composite strip. By only changing the structural design of the forming mold, copper-aluminum composite plates of different shapes can be formed, and the production cost is low. The forming mold and the pressure application method have no stress concentration, the plate-shaped copper-aluminum composite strip is subjected to consistent force and uniform deformation, which can effectively protect the copper-aluminum composite interface and the interface strength is less affected.

[0032] (5) The forming process of the copper-aluminum composite busbar of the present invention, by setting appropriate composite rolling process parameters, makes the interface structure of the copper-aluminum composite busbar plate stable and the bonding firm; appropriate flexible medium pressure rise rate, holding time and pressure reduction process make the copper-aluminum composite busbar uniformly pressurized, and the conductivity and interface strength of the copper-aluminum composite busbar formed by flexible medium do not change significantly.

[0033] This invention uses a liquid flexible medium to transmit pressure and complete the plastic deformation of copper-aluminum composite bars such as extrusion and bending. Under the premise of ensuring the quality of the copper-aluminum interface, copper-aluminum composite bars of various shapes can be produced in one go with high precision. Attached Figure Description

[0034] These and / or other aspects and advantages of the present invention will become clearer and more readily understood from the following detailed description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0035] Figure 1 This is a schematic front view of the molding die for the copper-aluminum composite busbar in Embodiment 1 of the present invention;

[0036] Figure 2 This is a cross-sectional view of the forming mold for the copper-aluminum composite busbar in Embodiment 1 of the present invention. Figure 1 The image shows the result obtained by cutting along the dashed lines shown.

[0037] Figure 3 A schematic diagram of the casting and rolling process for forming the copper-aluminum composite busbar in Embodiment 2 of the present invention;

[0038] Figure 4 The vertical axis represents the hydraulic pressure used in the flexible media forming process in Embodiment 2 of the present invention, and the horizontal axis represents the time.

[0039] Among them: 1-top material rod, 2-lower mold, 3-edge of square groove, 4-plate-shaped copper-aluminum composite strip, 5-pressure ring, 6-injection port, 7-degassing box, 8-argon gas, 9-filter box, 10-liquid level control system, 11-spraying port, 12-casting roll, 13-copper coil winding system, 14-shearing machine, 15-copper-aluminum composite plate coil. Detailed Implementation

[0040] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Example 1:

[0042] A molding die for a copper-aluminum composite bar, the structure of which is as follows: Figure 1-2 As shown, it includes an ejector rod 1, a lower mold 2, a pressure ring 5, and an oil injection port 6. The lower mold 2 is a support structure with a square groove in the center of its upper surface and a through hole in the center of the square groove. The ejector rod 1 is set in the through hole in the center of the square groove of the lower mold 2 and can move up and down controllably within the through hole. The pressure ring 5 is set on the upper part of the square groove of the lower mold 2 and is fixedly connected and pressed with the edge of the square groove of the lower mold 2 and the plate copper-aluminum composite strip 4 in the forming process of the plate copper-aluminum composite strip 4. The oil injection port 6 is set in the center of the pressure ring 5 and is used to inject a flexible medium into the upper surface of the plate copper-aluminum composite strip 4 to form a plastic forming pressure on the upper surface of the plate copper-aluminum composite strip 4.

[0043] To better achieve the purpose of the invention, the preferred configuration of this embodiment is as follows:

[0044] The edges of the square groove opening 3 and the center through hole opening of the square groove of the lower mold 2 are rounded; the radius of the rounded corner of the square groove opening is more preferably 20%-50% of the thickness of the plate copper-aluminum composite strip 4.

[0045] The flexible medium is a liquid medium, more preferably hydraulic oil, which is injected into the injection port 6 through a hydraulic press;

[0046] The material of the lower mold 2 is Cr12 alloy tool steel;

[0047] The material of the pressure ring 5 is 40Cr special steel;

[0048] The pressure ring 5 is locked to the edge of the square groove of the lower mold 2 and the plate copper-aluminum composite strip 4 between them by bolts, and is pressed by the pressure head of the hydraulic press according to the preset pressure force.

[0049] Example 2

[0050] A forming process for a copper-aluminum composite busbar, using the forming mold for the copper-aluminum composite busbar described in Example 1, includes the following steps:

[0051] Step 1: Preparation of raw materials for copper-aluminum composite busbars and plate-shaped copper-aluminum composite busbars;

[0052] Mature grades of industrial pure copper TU1 and electrical aluminum 1050 were selected as precursors for copper-aluminum composites.

[0053] Use such as Figure 3 The structure, equipment, and process flow are shown below:

[0054] The structural equipment includes: a degassing box 7, a filter box 9, a liquid level control system 10, a casting nozzle 11, and a casting roll 12, which are connected in sequence. The degassing box 7 is used to remove gas; the filter box is used to filter impurities; the liquid level control system 10 is used to control the aluminum liquid flow rate and liquid level; the casting nozzle is used to spray out the aluminum liquid; and the casting roll 12 is used to wind copper coils rolled from industrial pure copper TU1 and aluminum liquid. The specific method process is as follows:

[0055] The process flow is as follows: molten electrical aluminum is obtained, and the solution is kept at 800-1200℃. Degassing is then performed in a degassing box 7 (by introducing argon gas 8 into the degassing box 7 to remove gaseous impurities). The solution then passes through a filter box 9 (containing filter plates to remove inclusions), and continues to pass through a liquid level control system 10 and a casting nozzle 11. It is then compositely cast and rolled with an industrial pure copper coil pre-wound on a casting roll 12. After heat treatment (quenching at 550℃ for 4 hours) and annealing (at 350℃ for 3 hours), a plate-shaped copper-aluminum composite busbar is obtained. The busbar is then thinned by alternating hot rolling and cold rolling (achieving a thinning amount of 50%) to obtain the plate-shaped copper-aluminum composite busbar. The process parameters for composite casting and rolling are as follows: the casting and rolling speed is 800-1200 mm / min; the rolling is driven by a hydraulic press with a cylinder pressure of 20 tons; the height difference between the molten aluminum surface and the injection nozzle 11 is adjusted to 20 mm via the liquid level control system 10; the resulting plate-shaped copper-aluminum composite busbar has a thickness of 20 mm and a width of 710 mm. Figure 3 In the diagram, number 13 is the copper coil winding system used to control the release speed of the copper coil to match the casting and rolling; number 14 is the shearing machine used to shear plate-shaped copper-aluminum composite bars; and number 15 is the plate-shaped copper-aluminum composite coil.

[0056] Step 2: Installation of the plate-shaped copper-aluminum composite busbar on the copper-aluminum composite busbar mold;

[0057] After ultrasonic cleaning of the surface of the plate copper-aluminum composite busbar obtained in step S1, it is placed on the lower mold 2 of the forming mold of the copper-aluminum composite busbar in Example 1, and then the pressure ring 5 is covered and locked, and pressed according to the preset pressure force (the preset pressure force is 1.1 tons, which is achieved by a hydraulic press). Then, the ejector rod 1 is reset to the plane of the square groove opening of the lower mold 2 or even below the bottom plane of the square groove. Flexible medium is injected into the upper surface of the plate copper-aluminum composite busbar 4 through the oil injection hole 6. The flexible medium is preferably hydraulic oil with the grade L-HM46.

[0058] Step 3: Hydraulic oil pressure molding;

[0059] The plate-type copper-aluminum composite panel is pressure-formed by injecting flexible medium through oil injection hole 6. The hydraulic force is generated using a forced press method, relying on a hydraulic press (a YQ32-315 100-ton four-column vertical hydraulic press from Zhongyou Heavy Industry) to force oil supply and pressurize, ensuring early forming of the copper-aluminum composite panel. The hydraulic pressure is controlled by a proportional valve, and the pressure control process is as follows: Figure 4 As shown, the specific process is as follows: the pressure is increased to 30MPa at a constant speed within 0-30 seconds, the pressure is maintained at this level for 1 minute, and then the pressure is released within 30 seconds.

[0060] Step 4: Depressurize and demold;

[0061] After the plate copper-aluminum composite busbar is formed by the pressure generated by the flexible medium, the pressure in the oil injection hole 6 is first released, then the pressure of the hydraulic press head acting on the pressure ring 5 is released, and finally the formed copper-aluminum composite busbar is ejected by moving the ejector rod 1.

[0062] Step 5: Follow-up processing;

[0063] After molding, the copper-aluminum composite busbars are ultrasonically cleaned by immersion in acetone, and then subjected to stress annealing. Annealing is carried out in a vacuum tube furnace (Yagelong, GS1200) at 350℃ for 3 hours, with high-purity argon continuously introduced as a protective gas. The annealed copper-aluminum composite busbars can be wire-cut to the actual size required for use and then surface polished for convenient subsequent performance testing.

[0064] Performance testing;

[0065] Performance tests were conducted on the copper-aluminum composite busbars after all treatments were completed. Hardness was tested using a Vickers hardness tester (Yino, FALCON 511). The interfacial peel strength before and after plastic deformation was greater than 30 N / mm, with no significant change, and the hardness increased from 55-65 HB to over 70 HB. Resistivity was tested using the four-probe method, with equipment including a constant current source (HY, 3003-2) and a digital multimeter (Agilent, 34401A). Test results showed that the conductivity before deformation was 98.79% IACS, and the conductivity after deformation was 99.10% IACS, with no significant change.

[0066] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A forming mold for a copper-aluminum composite bar, characterized in that, Includes ejector pin (1), lower die (2), pressure ring (5), and oil injection port (6); The lower mold (2) is a support structure with a square groove in the center of the upper surface and a through hole in the center of the square groove; The ejector rod (1) is set in the central through hole of the square groove of the lower mold (2) and can move up and down controllably within the through hole; The pressure ring (5) is set on the upper part of the square groove of the lower mold (2), and is fixedly connected and pressed with the edge of the square groove of the lower mold (2) and the plate copper-aluminum composite strip (4) in the forming process of the plate copper-aluminum composite strip (4); The oil injection port (6) is located at the center of the pressure ring (5) and is used to inject flexible medium into the upper surface of the plate copper-aluminum composite busbar (4) to form plastic pressure on the upper surface of the plate copper-aluminum composite busbar (4). The edges (3) of the square groove opening and the edges of the central through hole opening of the square groove of the lower mold (2) are rounded. The flexible medium is a liquid medium; The radius of the rounded corner at the edge of the square groove of the lower mold (2) is 20%-50% of the thickness of the plate copper-aluminum composite strip (4); The material of the lower mold (2) is Cr12 alloy tool steel; The material of the pressure ring (5) is 40Cr special steel; The pressing ring (5) and the square groove edge of the lower mold (2) and the plate copper-aluminum composite strip (4) between them are locked by bolts and pressed by the press head of the hydraulic press according to the preset pressing force; The liquid medium is hydraulic oil, which is injected into the oil inlet (6) by a hydraulic press.

2. A forming process for a copper-aluminum composite busbar, characterized in that, It uses the forming mold of the copper-aluminum composite busbar as described in claim 1, and includes the following steps: S1. Raw materials and preparation of copper-aluminum composite busbar: Industrial pure copper and electrical aluminum are selected as precursors for copper-aluminum composite busbar. Aluminum is obtained by melting electrical aluminum and then casting it with rolled copper coil to obtain plate copper-aluminum composite busbar (4). S2. After ultrasonic cleaning of the surface of the plate copper-aluminum composite busbar obtained in step S1, place it on the lower mold (2) of the forming mold of the copper-aluminum composite busbar in claim 1, then cover it with the pressure ring (5) and lock it, and press it according to the preset pressure force. Then reset the ejector rod (1) to the plane of the square groove opening of the lower mold (2) or even below the plane of the bottom of the square groove, and inject flexible medium into the upper surface of the plate copper-aluminum composite busbar (4) through the oil injection port (6). S3. The plate copper-aluminum composite busbar is pressure-shaped by the flexible medium injected through the oil injection port (6); S4. After the plate copper-aluminum composite busbar is formed by the pressure generated by the flexible medium, the pressure in the oil injection port (6) is first removed, then the pressure of the hydraulic press head acting on the pressure ring (5) is removed, and finally the formed copper-aluminum composite busbar is ejected by moving the top rod (1). S5. After the formed copper-aluminum composite busbar is ultrasonically cleaned by immersion in acetone, it undergoes stress annealing treatment.

3. The forming process of the copper-aluminum composite busbar as described in claim 2, characterized in that, In step S1 The industrial pure copper is industrial pure copper TU1; The electrical aluminum is electrical aluminum 1050; A rolling system comprising the following structure is used: a degassing box (7), a filter box (9), a liquid level control system (10), a casting nozzle (11), and a casting roll (12), which are connected in sequence. The degassing box (7) is used to remove gas; the filter box is used to filter impurities; the liquid level control system (10) is used to control the flow rate and liquid level of the molten aluminum; the casting nozzle is used to spray out the molten aluminum; and the casting roll (12) is used to wind the copper coils rolled from industrial pure copper TU1 and the molten aluminum. The specific process is as follows: The molten aluminum is obtained by melting electrical aluminum, which is kept at 800~1200℃ and degassed in a degassing box (7). After passing through a filter box (9), it continues to pass through a liquid level control system (10) and a casting nozzle (11) in sequence, and is composite cast with an industrial pure copper coil pre-wound on a casting roll (12). Then, after heat treatment and annealing, a plate-shaped copper-aluminum composite busbar is obtained. It is then thinned by alternating hot rolling and cold rolling to obtain a plate-shaped copper-aluminum composite busbar.

4. The forming process of the copper-aluminum composite busbar as described in claim 3, characterized in that, In the process of step S1: The parameters for rolling molten aluminum with industrial pure copper coils are as follows: the casting and rolling speed is 800-1200 mm / min, the rolling is driven by a hydraulic press, the hydraulic press cylinder pressure is 20 tons, and the height difference between the molten aluminum liquid level and the injection nozzle (11) is adjusted to 20 mm through the liquid level control system (10); the thickness of the resulting plate-shaped copper-aluminum composite strip is 20 mm and the width is 710 mm. The resulting plate-shaped copper-aluminum composite bar is then subjected to multiple stages of hot rolling and cold rolling to achieve a thickness reduction of 50%.

5. The forming process of the copper-aluminum composite busbar as described in claim 3, characterized in that, The heat treatment and annealing process in step S1 includes: heat treatment by quenching at 550°C for 4 hours; and annealing at 350°C for 3 hours.

6. The forming process of the copper-aluminum composite busbar as described in claim 3, characterized in that, In step S2, the preset blank holder force is 1.1 tons; In step S4, the pressure generated by the flexible medium is achieved by a hydraulic press; the hydraulic press is a YQ32-315 type 100-ton four-column vertical hydraulic press of Zhongyou Heavy Industry; after the oil pump of the hydraulic press starts to work, it goes through three stages of pressure increase, pressure holding and pressure reduction, and the copper-aluminum composite bar (4) to be formed is pressure plasticized by the flexible medium.

7. The forming process of the copper-aluminum composite busbar as described in claim 6, characterized in that, In step S4, the pressure mechanism applied by the hydraulic press to the flexible medium is as follows: the pressure is increased to 30MPa at a constant speed within 0-30 seconds, the pressure is maintained at this pressure for 1 minute, and then the pressure is released within 30 seconds.

8. The forming process of the copper-aluminum composite busbar as described in claim 3, characterized in that, In step S5, the annealing process is carried out in a vacuum tube furnace. High-purity argon gas is continuously introduced as a protective gas during the annealing process. The annealing temperature is 350°C and the time is 3 hours.

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