A method for preparing copper-aluminum composite busbars

Abstract

This invention provides a method for preparing a copper-aluminum composite strip, comprising the following steps: copper plates are spaced apart to form gaps; molten aluminum is poured into the gaps between the copper plates; high-temperature resistant baffles are installed on the sides and bottom of the two sets of copper plates to prevent leakage of the molten aluminum; after the molten aluminum has partially solidified, the high-temperature resistant baffles are removed; and the strip is then hot-rolled using rollers to form a three-layer copper-aluminum-copper composite material; S1: the three-layer copper-aluminum-copper composite roll is leveled; S2: the three-layer copper-aluminum-copper composite roll is pulled through a drawing die with a rounded corner and straight groove structure in the forming cavity, so that the sides of the copper layer form rounded corners along the direction of the aluminum layer; S3: the uncovered corners are coated with molten copper. The aluminum layer in this technical solution is not covered by copper layers on both sides. During the drawing process, this provides space for the copper layer to extend. The rounded corners formed by the copper layer can cover the aluminum layer, maintaining excellent conductivity of the copper-aluminum composite busbar while reducing its thickness and increasing its width. The copper-aluminum interface has high bonding strength, which can effectively transfer load. When the material is subjected to external impact, it is not easy to deform or even break, resulting in stable and reliable quality. The aluminum layer portion not covered by the copper liquid is brush-plated, so that the aluminum layer is not exposed. This ensures the best conductivity of the copper-aluminum composite busbar while also reducing its manufacturing cost.

Description

Technical Field

[0001] This invention relates to the field of production technology of copper-clad aluminum busbars for electrical applications, and specifically to a method for preparing copper-aluminum composite busbars. Background Technology

[0002] With the development of power and electrical technology and the research and development of high-voltage, high-current equipment, the demand for busbars—the connection materials between application equipment and power input—is increasing. Currently, the commonly used materials for busbars are pure copper or electrical pure aluminum. Pure copper has good conductivity but is expensive, scarce, and dense. Electrical pure aluminum, while inexpensive, abundant, and has low density, has less than ideal conductivity, especially at connection points where contact resistance is high, making joints prone to melting. Therefore, the search for a conductive material that combines the advantages of both pure copper and electrical pure aluminum has led to the emergence of copper-aluminum composite busbars.

[0003] Among the existing copper-clad aluminum busbar production methods, the most common method is the tube stretching and rolling method; which involves placing an aluminum rod inside a copper tube, stretching it to form a solid bond, then annealing, rolling, deforming, and stretching it again to produce a copper-clad aluminum busbar.

[0004] Achieving copper-aluminum metallurgical bonding through a stretching process has the following problems;

[0005] On the one hand, since the aluminum layer is completely covered with a copper layer, the copper-aluminum composite busbar must maintain a certain thickness during the rolling and drawing process. If it is too thin, the copper layer on the outer periphery will be crushed. Therefore, the size of copper-clad aluminum busbar production is limited and it is only suitable for the production of small-sized copper-clad aluminum busbars.

[0006] Moreover, the bonding effect of copper and aluminum interface is poor, and it cannot effectively transfer load. When the material is subjected to external force impact, it is easy to cause deformation or even breakage, making the quality of copper-aluminum composite busbar unstable.

[0007] On the other hand, copper-clad aluminum busbars produced using this method still have a relatively high copper content, resulting in high costs. Summary of the Invention

[0008] In view of this, the problem to be solved by the present invention is to provide a method for preparing copper-aluminum composite busbars.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0010] A method for preparing a copper-aluminum composite busbar includes the following steps;

[0011] S1: Level the copper-aluminum-copper three-layer composite roll material;

[0012] S2: Pull the copper-aluminum-copper three-layer composite coil through the drawing die, so that the side of the copper layer forms an arc-shaped wrapping corner along the direction of the aluminum layer;

[0013] S3: The aluminum layer not covered by the corner is plated with copper liquid.

[0014] S1 is: using a horizontal rolling mechanism to roll the copper-aluminum-copper three-layer composite coil flat, and using a guide limiting mechanism to align the copper-aluminum-copper three-layer composite coil with the entrance of the drawing die.

[0015] The horizontal rolling mechanism is a horizontal roller group, and the guiding and limiting mechanism is a vertical roller group.

[0016] The forming cavity of the drawing die has a rounded corner straight groove structure.

[0017] It also includes a drawing drive mechanism, the output end of which is connected to a gripper for holding a copper-aluminum-copper three-layer composite coil, the gripper being positioned facing the exit of the drawing die.

[0018] The pulling drive mechanism is a hydraulic cylinder.

[0019] The copper-aluminum composite busbar is cut into L-shaped copper-aluminum composite busbar elbows, and the cut surfaces are plated with copper liquid.

[0020] The advantages and positive effects of this invention are:

[0021] (1) The copper-aluminum composite busbar produced by this technical solution has a better interface bonding between the copper and aluminum layers, which can effectively transfer the load. When the material is subjected to external force impact, it is not easy to cause deformation or even breakage, and the quality is stable and reliable.

[0022] (2) Compared with the traditional design of aluminum material with copper material on the outside, the aluminum layer in this technical solution is not covered by copper layer on both sides. During the drawing process, it can provide space for the extension of copper layer. The arc-shaped corner formed by copper layer can cover aluminum layer, so that copper-aluminum composite busbar maintains excellent conductivity while reducing the overall thickness of copper-aluminum composite busbar and increasing width.

[0023] (3) The aluminum layer not covered by copper liquid is brush-plated to ensure that the aluminum layer is not exposed. This not only ensures the better conductivity of the copper-aluminum composite busbar, but also reduces the manufacturing cost of the copper-aluminum composite busbar. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is a structural diagram of a copper-aluminum-copper three-layer composite roll material in a method for preparing a copper-aluminum composite strip according to the present invention;

[0026] Figure 2 This is a structural diagram of the manufactured copper-aluminum composite busbar;

[0027] Figure 3 This is a structural diagram of a copper-aluminum composite elbow.

[0028] Figure 4 This is a structural diagram of a copper-aluminum composite bar preparation method of the present invention, which includes a horizontal roller group, a vertical roller group, and a drawing die;

[0029] Figure 5 This is a structural diagram of a copper-aluminum composite bar preparation method of the present invention, which includes a clamp and a hydraulic cylinder;

[0030] Figure 6 This is a structural diagram of a hand clamp;

[0031] In the diagram: copper layer 11, aluminum layer 12, corner protector 21, molten copper 22, gripper 31, drawing die 32, hydraulic cylinder 33, horizontal roller group 41, vertical roller group 42. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] In existing technologies, copper-aluminum composite busbars manufactured using the sleeve stretching and rolling method exhibit poor bonding at the copper-aluminum interface. This technical solution, through research, reveals that this is because in the sleeve stretching and rolling method, aluminum and copper rely on external force for mutual penetration, resulting in gaps at the copper-aluminum interface. This prevents the material from effectively transferring load, making it prone to deformation or even fracture when subjected to external impact, leading to unstable quality of the copper-aluminum composite busbar. Furthermore, the sleeved copper method necessitates maintaining a certain thickness for the copper-aluminum composite busbar; excessive thinness causes extrusion cracks in the outer copper layer, limiting the manufacturing dimensions of the copper-aluminum composite busbar.

[0036] Therefore, in view of the shortcomings of the existing technology, the present invention provides a method for preparing copper-aluminum composite strips, the raw material of which is made of copper-aluminum-copper three-layer composite roll material, and the manufacturing process of copper-aluminum-copper three-layer composite roll material is as follows:

[0037] Copper plates are spaced apart to create gaps between them. Molten aluminum is poured into the gaps between the copper plates. High-temperature resistant baffles are installed on the sides and bottom of the two sets of copper plates to prevent the molten aluminum from leaking. After the molten aluminum has partially solidified, the high-temperature resistant baffles are removed and the mixture is hot-rolled to form a copper-aluminum-copper three-layer composite material.

[0038] like Figure 1 As shown, the aluminum liquid casting method is used to expel the air between the copper layer 11, the aluminum layer 12, and the copper layer 11, so that the three metal plates are seamless and the copper and aluminum layers permeate each other. Finally, the permeation effect is enhanced by hot rolling and shaping. This results in better bonding between the copper and aluminum layers, which can effectively transfer the load. When the material is subjected to external impact, it is not easy to deform or even break, and the quality is stable and reliable.

[0039] The preparation method of copper-aluminum composite busbar includes the following steps;

[0040] S1: The copper-aluminum-copper three-layer composite coil is leveled, and the copper-aluminum-copper three-layer composite coil is rolled flat using a horizontal rolling mechanism. The copper-aluminum-copper three-layer composite coil is aligned with the entrance of the drawing die using a guide and limiting mechanism. In this embodiment, the horizontal rolling mechanism is a horizontal roller group 41, and the guide and limiting mechanism is a vertical roller group 42.

[0041] Specifically, the two horizontal rollers of the horizontal roller group 41 are set at different heights, so that a gap is formed between the two horizontal rollers. The copper-aluminum-copper three-layer composite coil is pressed in the height direction to flatten the coil and prevent the coil from bending and curling.

[0042] The two vertical rollers of the vertical roller group are set horizontally, and a guide channel is formed between the two vertical rollers. This restricts the movement direction of the copper-aluminum-copper three-layer composite coil in the width direction, so that the copper-aluminum-copper three-layer composite coil is aligned with the entrance of the drawing die.

[0043] S2: As Figure 2 As shown, a copper-aluminum-copper three-layer composite coil is held by a clamp. The output end of the drawing drive mechanism is connected to the clamp 31. The drawing drive mechanism adopts a hydraulic cylinder 33. Under the pulling action of the drawing drive mechanism, the copper-aluminum-copper three-layer composite coil passes through the drawing die. The forming cavity of the drawing die 32 has a rounded corner straight groove structure, so that the side of the copper layer 11 forms an arc-shaped wrapping corner 21 along the direction of the aluminum layer 12. The drawing drive mechanism can be a hydraulic cylinder.

[0044] Compared to the traditional design of aluminum material surrounded by copper material, this technical solution does not have copper layers covering both sides of the aluminum layer. During the drawing process, space can be provided for the extension of the copper layer. The arc-shaped corners formed by the copper layer can cover the aluminum layer, which not only maintains the excellent conductivity of the copper-aluminum composite busbar, but also reduces the overall thickness of the copper-aluminum composite busbar and increases its width. According to experimental comparison, the copper-aluminum composite busbar manufactured by the traditional sleeve stretching and rolling method has a width of 120mm and a thickness of 5mm, while the copper-aluminum composite busbar prepared by this technical solution has a width of 200mm and a thickness of 3mm.

[0045] S3: As Figure 2 As shown, since the corner 21 formed by the copper layer 11 cannot completely cover the aluminum layer 12, the exposed aluminum layer 12 will increase the resistance and reduce the conductivity due to the "skin effect" principle of charge. Therefore, the part of the aluminum layer 12 not covered by the corner 21 is coated with copper liquid 22 so that the aluminum layer 12 is not exposed. In addition, the manufacturing cost of the copper-aluminum composite busbar is reduced by using copper liquid to replace part of the original copper coating.

[0046] Furthermore, due to the requirements of the operating conditions, L-shaped copper-aluminum composite elbows are needed. In the existing technical solutions, most are made by welding two copper-aluminum composite elbows together, which will result in high contact resistance at the connection point and make the joint prone to melting accidents.

[0047] like Figure 3 As shown, this technical solution involves cutting an L-shaped copper-aluminum composite busbar elbow from a rectangular copper-aluminum composite busbar. The exposed aluminum cut surface is then plated with copper liquid 22. The copper-aluminum composite busbar elbow manufactured in this way has no welding points, and the absence of welding points results in good electrical conductivity.

[0048] The working principle and process of this invention are as follows:

[0049] S1: Level the copper-aluminum-copper three-layer composite roll material;

[0050] The horizontal roller group presses the copper-aluminum-copper three-layer composite coil in the height direction, flattening the coil and preventing it from bending or warping. The two vertical rollers of the vertical roller group are set horizontally, and a guide channel is formed between the two vertical rollers. This restricts the movement direction of the copper-aluminum-copper three-layer composite coil in the width direction, so that the copper-aluminum-copper three-layer composite coil is aligned with the entrance of the drawing die.

[0051] S2: The copper-aluminum-copper three-layer composite coil is held by a clamp. The output end of the hydraulic cylinder is connected to the clamp. Under the pulling action of the hydraulic cylinder, the copper-aluminum-copper three-layer composite coil passes through the drawing die. The drawing die has a rounded corner straight groove structure, so that the side of the copper layer forms an arc-shaped wrapping corner along the direction of the aluminum layer. During the drawing process, the copper-aluminum-copper three-layer composite coil can provide space for the side extension of the copper layer. The arc-shaped wrapping corner formed by the copper layer can cover the aluminum layer, so that the copper-aluminum composite busbar maintains excellent conductivity while reducing the overall thickness of the copper-aluminum composite busbar. The copper-aluminum composite busbar prepared by this technical solution can reach a width of 200mm and a thickness of 3mm.

[0052] S3: Apply copper liquid to the aluminum layer that is not covered by the corner, so that the aluminum layer is not exposed; avoid the aluminum layer being exposed due to the "skin effect" of the charge, which would increase the resistance and reduce the conductivity.

[0053] S4: The multi-copper-aluminum composite busbar undergoes polishing, brush plating, and drying processes in sequence, followed by packaging.

[0054] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. A method for preparing a copper-aluminum composite busbar, characterized in that, Includes the following steps; Copper plates are spaced apart to create gaps between them. Molten aluminum is poured into the gaps between the copper plates. High-temperature resistant baffles are installed on the sides and bottom of the two sets of copper plates to prevent the molten aluminum from leaking. After the molten aluminum has partially solidified, the high-temperature resistant baffles are removed and the mixture is hot-rolled to form a copper-aluminum-copper three-layer composite material. S1 levels the copper-aluminum-copper three-layer composite roll material; S2: Pull the copper-aluminum-copper three-layer composite coil through the drawing die with a rounded corner and straight groove structure in the forming cavity, so that the side of the copper layer forms an arc-shaped wrapping corner along the direction of the aluminum layer; S3: The aluminum layer not covered by the corner is plated with copper liquid.

2. The method for preparing a copper-aluminum composite busbar according to claim 1, characterized in that, S1 is: using a horizontal rolling mechanism to roll the copper-aluminum-copper three-layer composite coil flat, and using a guide limiting mechanism to align the copper-aluminum-copper three-layer composite coil with the entrance of the drawing die.

3. The method for preparing a copper-aluminum composite busbar according to claim 2, characterized in that, The horizontal rolling mechanism is a horizontal roller group, and the guiding and limiting mechanism is a vertical roller group.

4. The method for preparing a copper-aluminum composite busbar according to claim 1, characterized in that, The forming cavity of the drawing die has a rounded corner straight groove structure.

5. The method for preparing a copper-aluminum composite busbar according to claim 1, characterized in that, It also includes a drawing drive mechanism, the output end of which is connected to a gripper for holding a copper-aluminum-copper three-layer composite coil, the gripper being positioned facing the exit of the drawing die.

6. The method for preparing a copper-aluminum composite busbar according to claim 5, characterized in that, The pulling drive mechanism is a hydraulic cylinder.

7. The method for preparing a copper-aluminum composite busbar according to claim 1, characterized in that, The copper-aluminum composite busbar is cut into L-shaped copper-aluminum composite busbar elbows, and the cut surfaces are plated with copper liquid.

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