Connection structure for aluminum-based bus duct having copper-clad end portions

Abstract

A connection structure for an aluminum-based bus duct having copper-clad end portions. The connection structure comprises a copper-aluminum eutectic electrically conductive bar, which comprises an aluminum alloy base layer A, wherein end portions at the upper and lower side surfaces of the aluminum alloy base layer A are clad with copper connection layers A, and a copper-aluminum eutectic layer A is provided between the aluminum alloy base layer A and each copper connection layer A. The connection structure further comprises a connector, which comprises several copper-aluminum eutectic connection sheets, and the copper-aluminum eutectic electrically conductive bar is clamped by the connector and tightly abuts against the copper-aluminum eutectic connection sheets. Taking into account the advantages of the low density and low cost of aluminum and the characteristics of copper, i.e., high electrical conductivity and corrosion resistance, only end portions of an aluminum base are clad with copper, thereby not only reducing the overall cost, but also ensuring the excellent performance of key parts, and achieving a balance between performance and cost; moreover, a copper-aluminum eutectic technique is used, thereby effectively solving the problems of weak interface bonding, large electrical resistance and susceptibility to corrosion, which easily occur when aluminum and copper are directly connected.

Description

A connection structure for aluminum-based copper-plated busbar trunking Technical Field

[0001] This utility model relates to the field of busbar technology, and in particular to a connection structure for an aluminum-based copper-plated busbar trough. Background Technology

[0002] In power transmission and distribution systems, busbars are key components responsible for the efficient and safe transmission of electrical energy. Traditional busbar materials are mainly copper and aluminum. Copper busbars are widely favored for their excellent conductivity and good mechanical strength, but their high cost and high density limit their use in some weight-sensitive or cost-critical applications. Although aluminum busbars have lower cost and lower density, their conductivity and mechanical strength are relatively lower, especially in high-temperature or harsh environments, where their performance deteriorates more significantly.

[0003] To combine the advantages of copper and aluminum, the industry has begun to explore the use of composite material busbars. Among them, the aluminum-based copper-coated busbar is an innovative design. This busbar maintains the low cost and low density advantages of aluminum while taking advantage of the high conductivity and good corrosion resistance of copper by covering the ends of the aluminum alloy substrate with a layer of copper, thus achieving an optimized balance between performance and cost.

[0004] However, existing copper-aluminum composite materials are almost all direct solid-solid composites of copper and aluminum. The direct connection between aluminum and copper often has the problem of weak interfacial bonding. In practical applications, due to the significant differences in the physical and chemical properties between copper and aluminum, direct bonding will generate potential differences due to the different materials, which will easily lead to electrochemical corrosion and increased contact resistance. In addition, a major challenge facing aluminum-based copper-plated busbars is how to ensure a reliable connection between aluminum and copper. Due to the significant differences in the physical and chemical properties of aluminum and copper, traditional connection methods such as welding and crimping are often unable to guarantee the stability and durability of the connection. Especially under harsh conditions such as high current, high temperature or vibration, the connection is prone to loosening or even breakage, which seriously affects the performance and safety of the busbar.

[0005] Based on this, the applicant proposed a connection structure for an aluminum-based copper-clad busbar trunking to solve the above technical problems. Technical issues

[0006] This invention addresses the shortcomings of existing technologies by providing a connection structure for an aluminum-based copper-plated busbar trough, ensuring a low-cost and reliable connection between the conductive busbar materials aluminum and copper. Technical solutions

[0007] This utility model is solved by the following technical solution: a connection structure for an aluminum-based copper-coated busbar, comprising a copper-aluminum eutectic conductive busbar, wherein the copper-aluminum eutectic conductive busbar comprises an aluminum alloy substrate layer A, the ends of the upper and lower sides of the aluminum alloy substrate layer A are covered with a copper connecting layer A, and the space between the aluminum alloy substrate layer A and the copper connecting layer A is the copper-aluminum eutectic layer A, and further comprising a connector, wherein the connector comprises a plurality of copper-aluminum eutectic connecting pieces, and the copper-aluminum eutectic conductive busbar is clamped by the connector and tightly abuts against the copper-aluminum eutectic connecting pieces.

[0008] Preferably, after the copper-aluminum eutectic conductive busbar is connected to the connector, the outer boundary of the copper connection layer A is equal to or exceeds the boundary of the copper-aluminum eutectic connection piece.

[0009] Preferably, the length of the copper connecting layer A at the end of the aluminum alloy substrate layer A accounts for 2% to 15% of the total length.

[0010] Preferably, the thickness of the copper interconnect layer A is 5% to 35% of the thickness of the copper-aluminum eutectic conductive bus.

[0011] Preferably, the thickness of the copper-aluminum eutectic conductive busbar is 1mm to 5mm.

[0012] Preferably, the thickness of the copper interconnect layer A is 0.1mm to 0.5mm.

[0013] Preferably, the copper-aluminum eutectic conductive busbar further includes a P1 busbar, the thickness of which is 0.5mm to 2.5mm.

[0014] Preferably, the copper-aluminum eutectic connector includes an aluminum alloy substrate layer B, and a copper connector layer B is coated on the aluminum alloy substrate layer B corresponding to the connector surface of the copper-aluminum eutectic busbar. The copper-aluminum eutectic layer B is located between the aluminum alloy substrate layer B and the copper connector layer B.

[0015] Preferably, the thickness of the copper connecting layer B is 5% to 35% of the thickness of the copper-aluminum eutectic connecting sheet.

[0016] Preferably, the thickness of the copper-aluminum eutectic connecting sheet is 1mm to 5mm.

[0017] Preferably, the thickness of the copper interconnect layer B is 0.1mm to 0.5mm.

[0018] Preferably, a tin-plated connection layer A is deposited on the outer side of the copper connection layer A, and a tin-plated connection layer B is deposited on the outer side of the copper connection layer B.

[0019] The outer side of the copper connecting layer A is electroplated with a silver connecting layer A, and the outer side of the copper connecting layer B is electroplated with a silver connecting layer B. Beneficial effects

[0020] The beneficial effects of this utility model are as follows:

[0021] 1. Optimization of performance and cost: The connection structure of this utility model combines the advantages of low density and low cost of aluminum with the high conductivity and corrosion resistance of copper. By covering the aluminum substrate with copper only at the ends, the overall cost is reduced while ensuring the excellent performance of key parts, achieving a perfect balance between performance and cost.

[0022] 2. Significantly improved connection reliability: By adopting copper-aluminum eutectic technology, a metallurgical bond is achieved between copper and aluminum through solid-liquid composite, forming a stable eutectic layer between the aluminum alloy substrate and the copper connecting layer. This effectively solves the problems of weak interface bonding, high resistance, and easy corrosion that easily occur when directly connecting aluminum and copper. This eutectic connection not only improves the mechanical strength of the connection, but also significantly reduces the contact resistance, ensuring the stable performance of the busbar under harsh conditions such as high current, high temperature, or vibration.

[0023] 3. Simplification and optimization of connection structure: The connection structure of this utility model uses a copper-aluminum eutectic connector, which utilizes several copper-aluminum eutectic connecting pieces to tightly abut against the copper-aluminum eutectic conductive busbar, to achieve fast, simple and reliable connection. At the same time, the tight fit between the connector and the conductive busbar also reduces the connection resistance and improves the conductivity.

[0024] 4. Enhanced corrosion resistance: The tin-plated connection layer on the outside of the copper connection layer not only improves the corrosion resistance of the connection parts, but also enhances the overall durability of the busbar. This design effectively resists the erosion of the external environment and extends the service life of the busbar.

[0025] 5. Flexibility and adaptability: By adjusting the thickness ratio of the aluminum alloy substrate and the copper connecting layer, as well as the overall thickness design of the conductive busbar, the connection structure of this utility model can flexibly adapt to the needs of different application scenarios. Whether it is the aerospace field with high requirements for lightweighting or the power transmission system with extremely high requirements for conductivity, a suitable product solution can be found. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be discussed below. Obviously, the technical solutions described in conjunction with the accompanying drawings are only some embodiments of this utility model. For those skilled in the art, other embodiments and their accompanying drawings can be obtained from the embodiments shown in these drawings without creative effort.

[0027] Figure 1 is a three-dimensional structural diagram of the connection state of this utility model.

[0028] Figure 2 is a three-dimensional structural diagram of the connection state of this utility model.

[0029] Figure 3 is a three-dimensional structural cross-sectional view of the connection state of this utility model.

[0030] Figure 4 is a schematic diagram of the copper-aluminum eutectic conductive busbar layer structure of this utility model.

[0031] Figure 5 is a schematic diagram of the copper-aluminum eutectic conductive busbar layer structure of this utility model.

[0032] Figure 6 is a cross-sectional view of the copper-aluminum eutectic bonding sheet layer structure of this utility model.

[0033] Figure 7 is a cross-sectional view of the copper-aluminum eutectic connecting sheet layer structure of this utility model.

[0034] Figure 8 is a schematic diagram of the layered structure of the copper-aluminum eutectic connecting sheet of this utility model.

[0035] Figure 9 is a connection diagram of this utility model.

[0036] Figure 10 is a schematic diagram of the busbar trunking of this utility model.

[0037] In the diagram: 1. Copper-aluminum eutectic conductive busbar, 11. P1 busbar, 101. Aluminum alloy substrate layer A, 102. Copper connector layer A, 103. Copper-aluminum eutectic layer A, 104. Tin connector layer A, 2. Connector, 21. Copper-aluminum eutectic connector piece, 211. Aluminum alloy substrate layer B, 212. Copper connector layer B, 213. Copper-aluminum eutectic layer B, 214. Tin connector layer B. Embodiments of the present invention

[0038] The technical solutions of various embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments described in this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0039] Example 1:

[0040] As shown in Figures 1 to 4, 6 to 7, and 9 to 10, this utility model discloses a connection structure for an aluminum-based copper-coated busbar groove, comprising a copper-aluminum eutectic conductive busbar 1. The copper-aluminum eutectic conductive busbar 1 includes an aluminum alloy substrate layer A101, with copper connecting layers A102 covering the upper and lower ends of the aluminum alloy substrate layer A101. A copper-aluminum eutectic layer A103 lies between the aluminum alloy substrate layer A101 and the copper connecting layer A102. The thickness of the copper-aluminum eutectic conductive busbar 1 is 5 mm, and the thickness of the copper connecting layer A102 is 0.5 mm. The copper-aluminum eutectic conductive busbar 1 also includes a P1 bar 11, the thickness of which is 2 mm. The structure is 0.5mm thick and also includes a connector 2. The connector 2 includes several copper-aluminum eutectic connecting pieces 21. The copper-aluminum eutectic conductive bus 1 is clamped by the connector 2 and tightly abuts against the copper-aluminum eutectic connecting pieces 21. The copper connecting layer A102 at the end of the aluminum alloy substrate layer A101 accounts for 2% to 15% of the total length. After the copper-aluminum eutectic conductive bus 1 is connected to the connector 2, the outer boundary of the copper connecting layer A102 is equal to or exceeds the copper-aluminum eutectic connecting piece 21. The boundary of the copper-aluminum eutectic connector 21 includes an aluminum alloy substrate layer B211, a copper connector layer B212 on the aluminum alloy substrate layer B211 corresponding to the connector surface of the copper-aluminum eutectic busbar 1, and a copper-aluminum eutectic layer B213 between the aluminum alloy substrate layer B211 and the copper connector layer B212. The thickness of the copper-aluminum eutectic connector 21 is 3 mm, the thickness of the copper connector layer B212 is 0.3 mm, and the thickness of the copper-aluminum eutectic layer B213 is 5 micrometers to 50 micrometers.

[0041] The connection structure of this utility model combines the advantages of low density and low cost of aluminum with the high conductivity and corrosion resistance of copper. By covering the aluminum substrate with copper only at the ends, the overall cost is reduced while ensuring the excellent performance of key parts, achieving a perfect balance between performance and cost.

[0042] Compared to traditional connection methods such as electroplating and brazing, the design using copper-aluminum eutectic busbars and copper-aluminum eutectic connectors increases heat dissipation, reduces the connection temperature under the same current carrying capacity, avoids damage to materials from high temperatures, and also reduces high-cost processes such as electroplating, thereby improving production efficiency and economy.

[0043] As shown in Figures 5 and 8, in another embodiment, the copper connecting layer A102 is electroplated with a tin connecting layer A104, and the copper connecting layer B212 is electroplated with a tin connecting layer B214. Tin plating prevents surface oxidation, improves the corrosion resistance of the connection parts, and enhances the overall durability of the busbar. This design effectively resists the erosion of the external environment and extends the service life of the busbar.

[0044] The copper connecting layer A102 is electroplated with a silver connecting layer A on the outside, and the copper connecting layer B212 is electroplated with a silver connecting layer B on the outside. The silver plating can improve the conductivity.

[0045] In the above embodiment, the connector 2 includes a plurality of insulating mounting plates disposed between two end caps, and the copper-aluminum eutectic connecting piece 21 is disposed on the insulating mounting plate.

[0046] Copper-aluminum eutectic refers to a low-melting-point eutectic alloy formed between copper and aluminum under certain temperature and pressure. This eutectic alloy has good wettability and fluidity, which can fill the tiny gaps between copper and aluminum to form a strong bond. At the same time, the copper-aluminum eutectic layer also has good electrical conductivity and corrosion resistance, which can improve the overall performance of the connector.

[0047] The insulating mounting plate includes one single-sided slot insulating mounting plate and four double-sided slot insulating mounting plates. The number of single-sided slot insulating mounting plates and double-sided slot insulating mounting plates is set according to actual needs and adapted to the busbar trunking. The single-sided slot insulating mounting plate is arranged adjacent to the end cover. The double-sided slot insulating mounting plate is arranged between the single-sided slot insulating mounting plate and another end cover. One copper-aluminum eutectic connecting piece 21 is provided on the single-sided slot insulating mounting plate, and two copper-aluminum eutectic connecting pieces 21 are symmetrically arranged on the double-sided slot insulating mounting plates.

[0048] A connecting cavity for clamping the copper-aluminum eutectic conductive busbar 1 is formed between adjacent insulating mounting plates, and a connecting cavity for clamping the P1 busbar 11 is formed between the end cap and the adjacent double-side slot insulating mounting plate.

[0049] The end cap has a protrusion in the middle of the side facing the insulating mounting plate, forming a gap with the adjacent single-sided slot insulating mounting plate to fit the auxiliary side plate of the busbar. The end cap has a mounting cavity on the side facing away from the insulating mounting plate, and a gasket is provided in the mounting cavity. The protrusion and mounting cavity design on the end cap enhance the structural strength of the device and facilitate installation and fixation.

[0050] An insulating sleeve passes through the end cap, the insulating mounting plate, and the copper-aluminum eutectic connecting piece 21. After the busbar torque bolt passes through the insulating sleeve, the copper-aluminum eutectic busbar 1 is clamped by tightening the nut at the end, ensuring the stability and safety of the connection.

[0051] Each copper-aluminum eutectic conductive busbar 1 is stacked in the busbar trunking and has an insulating layer on it to prevent short circuits between them. The insulating layer can be a single-layer polyester film. The smooth surface of the polyester film can prevent the film from being damaged by mutual squeezing and friction when the copper-aluminum eutectic conductive busbars 1 are stacked. Although the single-layer polyester film is very thin, it still affects heat dissipation. Using copper-aluminum eutectic conductive busbars 1 can improve heat dissipation. The wider the busbar, the better the heat dissipation. The base layer of the copper-aluminum eutectic conductive busbar 1 is an aluminum alloy base layer A101. Under the same weight or cost, the copper-aluminum eutectic conductive busbar 1 has better heat dissipation than copper busbars.

[0052] The copper-aluminum eutectic conductive busbar 1 and the copper-aluminum eutectic connecting piece 21 of this utility model are both copper-aluminum eutectic composite materials. A production process for this copper-aluminum eutectic composite material is provided, involving copper plate surface pretreatment, copper plate preheating, solid-liquid composite casting and rolling, composite slab homogenization annealing, cold rolling, secondary annealing, and slitting. This process includes the following steps:

[0053] Step A: Copper plate surface pretreatment: The copper plate is first subjected to high-pressure rinsing to quickly remove solid impurities from the surface of the copper plate, and then degreased by low-pressure rinsing to remove grease from the surface of the copper plate. Then, the oxide layer on the surface of the copper plate is polished off by steel brush equipment, and finally the copper plate is dried for use.

[0054] Step B: Copper plate preheating: The pretreated copper plate is fixedly fed into the feeding equipment and heated to 150℃~220℃ in an oxygen-free environment;

[0055] Step C: Solid-liquid composite casting and rolling: The aluminum ingot is heated to 660℃~710℃ to obtain molten aluminum liquid. Then, inert gas is introduced near the rolls to fill the casting and rolling environment and form an oxygen-free environment. At the same time, the outer surface temperature of the rolls is heated to 85℃~95℃. Cooling liquid is introduced into the rolls, and the casting and rolling equipment is started. In the oxygen-free environment, the molten aluminum liquid and the processed copper plate are brought into contact to achieve solid-liquid composite oxygen-free continuous casting and rolling, and copper-aluminum composite slab is obtained.

[0056] Step D: Homogenization annealing of composite slab: The obtained copper-aluminum composite slab is placed in an annealing furnace for homogenization annealing;

[0057] Step E: Cold rolling: The annealed composite slab is rolled a second time. The rolling equipment is adjusted to obtain the required plate thickness and width. The final plate thickness after the second rolling is 0.2 mm to 16 mm, of which the copper plate thickness is 5% to 35% of the overall composite plate thickness, and the plate width is 600 mm to 1200 mm.

[0058] Step F: Secondary annealing: The cold-rolled copper-aluminum composite plate is subjected to secondary annealing;

[0059] Step G: Cut into strips.

[0060] In step A, the rinsing solution is an alkaline degreasing solution at 50℃~70℃.

[0061] In step A, the steel brush equipment not only removes the oxide layer on the surface of the copper plate, but also increases the surface roughness, increases the copper-aluminum composite area, and thus enhances the adhesion of the composite material.

[0062] In step B, preheating the copper plate can increase the thermal activation energy of atoms, allowing atoms to acquire enough energy to migrate in a short time at high temperatures, forming a thicker eutectic layer, thereby effectively improving the bonding strength of the copper-aluminum composite interface.

[0063] In step C, the inert gas is nitrogen. Introducing nitrogen to create an oxygen-free environment can prevent the copper plate and aluminum liquid from forming an oxide layer due to direct exposure to air during the composite process, which would make it difficult to form an ideal eutectic layer and adversely affect the peel strength of the material.

[0064] In step C, introducing coolant into the rolls can increase the cooling rate of the casting and rolling process, forming smaller grains, thereby increasing the material strength. The rolling speed of the rolls is 600~1300 mm / min, the temperature of the coolant is 20℃~30℃, and the cooling rate is 300~1000℃ / s.

[0065] In step C, the composite rate after solid-liquid composite casting and rolling is 100%.

[0066] In step D, the heating temperature of the homogenization annealing process is 430℃~510℃, and the annealing time is 4h~5h. The homogenization annealing process can reduce intragranular segregation on both sides of the copper-aluminum alloy, remove residual stress, and improve the alloy performance.

[0067] In step F, the heating temperature of the secondary annealing process is 300℃~350℃, and it is cooled to below 80℃ in the annealing furnace. The secondary annealing process can refine the grains, adjust the microstructure, and eliminate microstructural defects. Since there is a certain internal stress during the rolling process, it will lead to a decrease in the strength of the composite material. The annealing process can reduce residual stress, stabilize dimensions, reduce deformation and cracking tendency, and ensure that the product has good comprehensive mechanical properties and good metallurgical bonding.

[0068] The skin effect of copper-aluminum eutectic composite material is not affected in current transmission, and its current carrying capacity is about 85% of that of pure copper conductor. Compared with copper busbar, it reduces the consumption of copper material and saves production costs.

[0069] The copper-aluminum eutectic composite material produced by this process has high shear strength and peel strength, and can achieve metallurgical bonding between composite metals to form a eutectic layer, which can meet the bonding strength requirements of the material. At the same time, compared with existing composite material production methods, the preparation method of this process is simpler, more economical and more efficient.

[0070] In this embodiment, in order to obtain the copper-aluminum eutectic conductive busbar 1 and copper-aluminum eutectic connecting piece 21 that meet the requirements, the relevant parameters in the production process of the copper-aluminum eutectic composite material can be appropriately adjusted so that the processed composite material meets the requirements.

[0071] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and not restrictive in all respects. The scope of this invention is defined by the appended claims, not by the foregoing description, and is therefore intended to encompass all variations falling within the meaning and scope of equivalents of the claims. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0072] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. Industrial applicability

[0073] The connection structure of the aluminum-based copper-plated busbar trunking in this application can ensure a low-cost and reliable connection between the aluminum and copper busbar materials, and has industrial applicability.

Claims

1. A connection structure for an aluminum-based copper-plated busbar trunking, characterized in that: The device includes a copper-aluminum eutectic conductive bus (1), which includes an aluminum alloy substrate layer A (101), and copper connecting layers A (102) covering the ends of the upper and lower sides of the aluminum alloy substrate layer A (101). A copper-aluminum eutectic layer A (103) is located between the aluminum alloy substrate layer A (101) and the copper connecting layer A (102). The device also includes a connector (2), which includes a plurality of copper-aluminum eutectic connecting pieces (21). The copper-aluminum eutectic conductive bus (1) is clamped by the connector (2) and closely abuts against the copper-aluminum eutectic connecting pieces (21).

2. The connection structure of an aluminum-based copper-plated busbar trunking according to claim 1, characterized in that: After the copper-aluminum eutectic conductive bus (1) is connected to the connector (2), the outer boundary of the copper connection layer A (102) is equal to or exceeds the boundary of the copper-aluminum eutectic connecting piece (21).

3. The connection structure of an aluminum-based copper-plated busbar trunking according to claim 1, characterized in that: The copper connecting layer A (102) provided at the end of the aluminum alloy substrate layer A (101) accounts for 2% to 15% of the total length.

4. The connection structure of an aluminum-based copper-plated busbar trunking according to claim 1, characterized in that: The thickness of the copper interconnect layer A (102) is 5% to 35% of the thickness of the copper-aluminum eutectic conductive bus (1).

5. The connection structure of an aluminum-based copper-plated busbar trunking according to claim 4, characterized in that: The thickness of the copper-aluminum eutectic conductive bus (1) is 1mm to 5mm.

6. The connection structure of an aluminum-based copper-plated busbar trunking according to claim 5, characterized in that: The thickness of the copper interconnect layer A (102) is 0.1 mm to 0.5 mm.

7. The connection structure of an aluminum-based copper-plated busbar trunking according to claim 1, characterized in that: The copper-aluminum eutectic connector (21) includes an aluminum alloy substrate layer B (211), and a copper connector layer B (212) is covered on the aluminum alloy substrate layer B (211) corresponding to the connector surface of the copper-aluminum eutectic busbar (1). Between the aluminum alloy substrate layer B (211) and the copper connector layer B (212) is a copper-aluminum eutectic layer B (213).

8. The connection structure of an aluminum-based copper-plated busbar groove according to claim 7, characterized in that: The thickness of the copper bonding layer B (212) is 5% to 35% of the thickness of the copper-aluminum eutectic bonding sheet (21).

9. The connection structure of an aluminum-based copper-plated busbar trunking according to claim 7, characterized in that: The copper connection layer A (102) is electroplated with a tin connection layer A (104) on the outside, and the copper connection layer B (212) is electroplated with a tin connection layer B (214) on the outside.

10. The connection structure of an aluminum-based copper-plated busbar groove according to claim 7, characterized in that: The copper connecting layer A (102) is electroplated with a silver connecting layer A on the outside, and the copper connecting layer B (212) is electroplated with a silver connecting layer B on the outside.

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