A copper-nickel composite terminal and a welding preparation process thereof

Abstract

The application discloses a copper-nickel composite terminal and a welding preparation process thereof, and comprises a copper terminal and a nickel sheet. The copper terminal is sequentially provided with a wire pressing skin part, a slot, a wire pressing core part and a curling claw from the free end to the composite part. The nickel sheet is provided with a claw joint surface, a anti-off head and a anti-off tail at both ends of the claw joint surface. The other end of the anti-off tail is sequentially provided with a nickel sheet bending step, a nickel sheet flat plate part and a concave compensation part for assembling and positioning with an aluminum bar. The copper terminal end presses the wire, solves the problem of pure nickel terminal sticking to the tool and short tool die life, and the nickel sheet end is laser welded with the aluminum bar to avoid the generation of brittle intermetallic compounds in the direct copper-aluminum welding. The curling claw covers the claw joint surface and cooperates with the anti-off head and the anti-off tail on both sides to limit the stop position, so that reliable pre-positioning can be realized before welding. The concave compensation part is matched with the aluminum bar slot, so that the X-axis and Y-axis positions can be directly determined during assembly without complex tooling. The fish scale-shaped weld formed by laser welding enables the copper-nickel to realize metallurgical bonding, and the bonding strength can reach more than 100 N.

Description

Technical Field

[0001] This invention relates to copper-nickel composite terminals, and more particularly to a copper-nickel composite terminal and its welding process. Background Technology

[0002] The wire harness CCS module is an important component of the battery module. In the industry, the connection between the wire harness and the aluminum battery in the traditional wire harness CCS module is usually achieved by ultrasonic welding or pure nickel sheet laser welding.

[0003] Ultrasonic welding solutions suffer from difficulties in rework and repair, low economic efficiency, and high requirements for process control. Currently, there is a lack of portable handheld ultrasonic welding equipment on the market that can meet the requirements for tensile and peel forces after welding, so most rework can only be completed by using nickel sheet laser welding.

[0004] In pure nickel sheet bonding solutions, the nickel sheet crimping end has high hardness, which can easily lead to problems such as blade sticking and die suction during wire crimping, resulting in a short die life. To ensure production, volatile oil and ultra-high alloy powder metallurgy high-speed steel blades (such as ASP60) are required, but the die life is only 60,000 to 80,000 cycles, resulting in high processing costs.

[0005] Furthermore, both ultrasonic welding and pure nickel sheet solutions have certain limitations in actual production, making it difficult to balance the processing economy of wire harness crimping with the reworkability of aluminum bar welding, which brings difficulties to the mass production and after-sales maintenance of wire harness CCS products. Summary of the Invention

[0006] To address the shortcomings of the aforementioned technologies, this invention provides a copper-nickel composite terminal and its welding preparation process.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: a copper-nickel composite terminal, comprising a copper terminal and a nickel sheet that are initially positioned relative to each other and subsequently welded to form a composite part; the copper terminal is provided with a wire pressing part, a notch, a wire pressing core part and a coiling claw in sequence from its free end to the composite part, the wire pressing part, the wire pressing core part and the coiling claw are all claw-shaped structures with wings on both sides; the nickel sheet is provided with a claw mating surface that cooperates with the coiling claw and anti-detachment head and anti-detachment tail located at both ends of the claw mating surface, the other end of the anti-detachment tail is in sequence a leveling nickel sheet bending step, a nickel sheet flat part and a concave filling part for assembly and positioning with the aluminum bar.

[0008] Furthermore, the curled claw bends from both sides of its wing portion to fit the claw mating surface. The width of both the anti-detachment head and the anti-detachment tail is greater than the width of the claw mating surface. After the curled claw clamps, the anti-detachment head and the anti-detachment tail form stop limits on both sides respectively.

[0009] Furthermore, a reinforcing rib is provided on the inner side wall of the wing of the wire core, and the length extension direction of the reinforcing rib is consistent with the extension direction of the wing of the wire core.

[0010] Furthermore, the notch is a recessed transition between the wire sheath and the wire core.

[0011] Furthermore, the nickel sheet bending step on the nickel sheet is a transition structure that is inclined towards the surface of the aluminum bar between the anti-tailing and the nickel sheet plate portion. The nickel sheet plate portion is formed in a way that is parallel to the aluminum bar. The nickel sheet plate portion is connected to a concave structure that bends inward and is matched with the slot opened on the aluminum bar.

[0012] Furthermore, the copper terminal is made of pure copper N6 material, and the nickel sheet is made of pure nickel N6-1 / 2H material with a thickness of 0.2±0.03mm; the composite part connecting the copper terminal and the nickel sheet is connected by laser welding after being limited by the curled claw and the claw mating surface, and the laser connection area at the composite part has a fish scale pattern weld.

[0013] A welding process for preparing a copper-nickel composite terminal includes the following steps: S1. Stamping process: Take copper terminals and nickel sheets and stamp them separately. The copper terminals are formed in sequence with wire pressing part, notch, wire pressing part and curling claw. The nickel sheets are formed in sequence with claw contact surface, anti-detachment head, anti-detachment tail, nickel sheet bending step, nickel sheet flat part and concave filling part. S2, punching process: punching the copper terminals and nickel sheets after stamping to the predetermined dimensions; S3. Forming process: The wire sheathing part, the wire core part, and the coiling claw are bent in sequence. The non-stripped end of the wire is pressed into the bent wire sheathing part. The stripped wire core is pressed into the bent wire core part. The claw surface of the nickel sheet is placed in the coiling claw. The coiling claw is bent inward from both sides of the wing and covers the claw surface. The anti-detachment head and anti-detachment tail are initially limited on both sides. At the same time, the concave filling part of the nickel sheet is assembled into the slot of the aluminum bar to complete the pre-positioning of the copper terminal and the nickel sheet. S4. Laser welding process: Laser welding is performed on the pre-positioned copper terminals and nickel sheets to form a composite part.

[0014] Furthermore, in the laser welding process, the peak laser welding power is 4.4~5.0KW, the pulse time is 2~5ms, the pulse frequency is 1HZ, and the composite part after welding has a fish scale pattern.

[0015] Furthermore, the S3 forming process also includes a wire crimping process, which automatically cuts the wire and then uses the upper and lower blades of the pneumatic mold to crimp the wire sheath and the wire core respectively, thus completing the crimping and fixing of the wire.

[0016] A copper-nickel composite terminal and its welding process are disclosed. The copper terminal is crimped with wire to solve the problems of pure nickel terminals sticking to the die and short die life. The nickel end is laser-welded to the aluminum bar to avoid the formation of brittle intermetallic compounds from direct copper-aluminum welding. Reliable pre-positioning can be achieved before welding by using curled claws to cover the claw mating surface and anti-detachment head and tail stops on both sides. The concave filling part matches the slotted aluminum bar, and the X and Y axis positions can be directly determined during assembly without complex tooling. The fish-scale weld formed by laser welding achieves a metallurgical bond between copper and nickel, with a bonding strength of over 100N. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the copper-nickel composite terminal of the present invention. Figure 1 .

[0018] Figure 2 This is a schematic diagram of the structure of the copper-nickel composite terminal of the present invention. Figure 2 .

[0019] Figure 3 This is a schematic diagram showing the production and use status of the present invention.

[0020] Figure 4 This is a partial schematic diagram showing the state of the invention in production and use.

[0021] Figure 5 This is a photograph of the copper-nickel composite terminal of the present invention.

[0022] Figure 6 This is a schematic diagram of the microstructure of the weld zone between the copper terminal and the nickel sheet.

[0023] In the diagram: 1. Copper terminal; 2. Nickel sheet; 3. Composite part; 4. Wire sheathing part; 5. Groove; 6. Wire core part; 7. Nickel sheet flat part; 8. Concave filling part; 9. Reinforcing rib; 10. Nickel sheet bending step; 11. Coiling claw; 12. Anti-detachment head; 13. Claw contact surface; 14. Anti-detachment tail. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1-6 As shown in the figure, this embodiment relates to a copper-nickel composite terminal and its welding preparation process. The copper-nickel composite terminal includes a copper terminal 1 and a nickel sheet 2 that are initially positioned relative to each other and then welded together to form a composite part 3.

[0026] Based on this, the copper terminal 1 is provided with a wire sheathing part 4, a notch 5, a wire core part 6, and a coiling claw 11 sequentially from its free end to the composite part 3. The wire sheathing part 4, the wire core part 6, and the coiling claw 11 are all claw-shaped structures with wings on both sides. In actual use, the wire sheathing part 4 is used to crimp the wire sheath of the wire, the wire core part 6 is used to crimp the wire core of the wire, and the coiling claw 11 is used to connect with the claw mating surface 13 on the nickel sheet 2 after bending. The number of coiling claws 11 is 2 to 6, which are symmetrically arranged or evenly spaced along both sides of the connection part, with an axial length of 1.0 mm to 2.0 mm and a width of 3 mm to 5.0 mm. In terms of material, the copper terminal 1 is preferably made of pure copper N6 material, and T2 pure copper or C19010 copper-nickel-silicon-phosphorus alloy can also be used. It has excellent conductivity, good compatibility with copper wire crimping, and is not prone to sticking to the die or suction during crimping. The service life of the die can be greatly improved compared with pure nickel terminals.

[0027] The nickel sheet 2 is provided with a claw surface 13 that mates with the curling claw 11, and anti-detachment heads 12 and anti-detachment tails 14 located at both ends of the claw surface 13. The other end of the anti-detachment tail 14 consists of a leveling nickel sheet bending step 10, a nickel sheet flat plate portion 7, and a concave filling portion 8 for assembly and positioning with the aluminum bar. The nickel sheet 2 is made of pure nickel N6-1 / 2H material with a thickness of 0.2±0.03mm. Pure nickel N2, N4, or N6 can also be used. It has excellent resistance to aluminum welding and corrosion. The side facing the aluminum bar can be directly used as the laser welding surface. The upper surface of the nickel sheet 2 needs to be cleaned, degreased, and activated before laser welding. The surface roughness Ra is 0.4μm~3.2μm. Depending on the requirements for corrosion resistance and conductivity, the upper surface can also be plated with tin, silver, gold, or nickel layers with a plating thickness of 0.5μm~5.0μm.

[0028] The curled claw 11 bends from both sides of its wing to fit the claw mating surface 13. The widths of the anti-detachment head 12 and anti-detachment tail 14 are both greater than the width of the claw mating surface 13. After the curled claw 11 clamps, the anti-detachment head 12 and anti-detachment tail 14 form stop limits on both sides respectively. With this structure, the copper terminal 1 and the nickel sheet 2 can be reliably initially limited before laser welding, preventing them from separating under force during subsequent assembly or handling. The composite part 3, which connects the copper terminal 1 and the nickel sheet 2, is connected by laser welding after being limited by the curled claw 11 and the claw mating surface 13. The laser enters from the upper surface of the nickel sheet 2, penetrates the nickel sheet 2 from top to bottom, and heats the surface of the lower copper terminal 1 to reach a molten state. The copper and nickel are infinitely dissolved in the liquid state, forming a metallurgical bond. The laser connection area at the composite part 3 has a fish-scale patterned weld, and the bonding strength can reach more than 100N. The laser used is an infrared fiber laser with a wavelength of 800nm ​​to 1080nm. The absorption rate of the nickel sheet 2 for this wavelength laser is 30% to 40%. The laser spot diameter is 0.05mm to 0.5mm, and the welding speed is 1mm / s to 50mm / s. The weld width is 0.2mm to 1.5mm, and the weld penetration depth is 0.05mm to 0.1mm, with a penetration depth of 0.05mm to 0.1mm in the nickel sheet 2 and a penetration depth of 0.05mm to 0.2mm in the copper terminal 1. The weld microstructure is Cu-Ni. It is an α-phase infinite solid solution, without any brittle intermetallic compound phases, and the interface has a continuous wavy interlocking structure. The Vickers hardness of the weld zone is 80HV to 150HV. During the welding process, the peak temperature of the weld zone is controlled between 100℃ and 300℃, and the welding cycle time of a single piece is 0.3s to 2.0s. The weld morphology can be one or a combination of continuous weld, circumferential weld, or multiple spot welds distributed at intervals.

[0029] A reinforcing rib 9 is provided on the inner wall of the wing of the wire core part 6. The length extension direction of the reinforcing rib 9 is consistent with the extension direction of the wing of the wire core part 6. It is used to enhance the holding force of the wire core part 6 on the wire core and improve the contact reliability and tensile strength after crimping. The notch 5 is a recessed transition between the wire skin part 4 and the wire core part 6, providing clearance space for bending and forming between the two, while reducing stress concentration.

[0030] The nickel sheet bending step 10 on the nickel sheet 2 is a transition structure that slopes towards the surface of the aluminum bar between the anti-tailing 14 and the nickel sheet plate 7. The nickel sheet plate 7 is formed in a way that is parallel to the aluminum bar. The nickel sheet plate 7 is connected to a concave structure that bends inward and is matched with the slot on the aluminum bar. During assembly, the concave filling part 8 is embedded in the slot of the aluminum bar to achieve positioning in the X and Y axis directions. The assembly position can be quickly determined without designing complex tooling, ensuring the consistency of batch assembly. The inclined transition of the nickel sheet bending step 10 can avoid interference between the terminal and the aluminum bar after the copper-nickel composite terminal crimps the wire.

[0031] The welding process for this copper-nickel composite terminal includes the following steps: S1. Stamping process: Take copper terminal 1 and nickel sheet 2, which are stamped and formed respectively. The copper terminal 1 is formed with wire pressing part 4, notch 5, wire pressing core part 6 and curling claw 11 in sequence. The nickel sheet 2 is formed with claw contact surface 13, anti-detachment head 12, anti-detachment tail 14, nickel sheet bending step 10, nickel sheet flat part 7 and concave filling part 8 in sequence. S2, punching process: punching the copper terminal 1 and nickel sheet 2 to the predetermined dimensions after stamping; S3, Forming process: The wire sheathing part 4, the wire core part 6, and the coiling claw 11 are bent in sequence. The non-stripped end of the wire is pressed into the bent wire sheathing part 4. The stripped wire core is pressed into the bent wire core part 6. The claw surface 13 of the nickel sheet 2 is placed in the coiling claw 11. The coiling claw 11 is bent from both sides of the wing to the inward side and covers the claw surface 13. The anti-detachment head 12 and anti-detachment tail 14 are initially positioned on both sides. At the same time, the concave filling part 8 of the nickel sheet 2 is assembled into the slot of the aluminum bar to complete the pre-positioning of the copper terminal 1 and the nickel sheet 2. S4. Laser welding process: Laser welding is performed on the pre-positioned copper terminal 1 and nickel sheet 2 to form composite part 3.

[0032] In the laser welding process, the peak laser welding power is 4.4–5.0 kW, the pulse time is 2–5 ms, and the pulse frequency is 1 Hz. After welding, the composite part 3 has a fish-scale pattern. The wider applicable power range is 50 W to 1000 W, which can be adjusted within this range according to the geometric dimensions of the overlapping area and the welding cycle requirements. The welding trajectory can be arranged in a straight line along the longitudinal direction of the joint area or in a ring along the outer periphery. During the welding process, coaxial or lateral blowing of protective gas can be used, and the overlap length of the weld area is 1–5 mm.

[0033] In the wire crimping process, the wire is automatically cut, and the clamps place the wire into the copper-nickel composite terminal crimping area. A special mold and blades are used; the blades are divided into upper and lower blades, which are fixed inside the mold. The mold moves the blades up and down under air pressure. The upper and lower blades of the pneumatically driven mold respectively crimp the wire sheath 4 and the wire core 6, completing the crimping and fixing of the wire. Different wire specifications correspond to different crimping parameters, with 0.22mm... 2 For example, the wire has the following specifications: core height 0.8±0.03mm, core width 1.35±0.10mm, skin height 1.55±0.05mm, skin width 1.65±0.10mm, tensile strength ≥30N, contact resistance ≤1mΩ, horizontal tensile force ≥90N, and operating temperature range -40℃~125℃.

[0034] In the stamping process, the choice of die material directly affects production efficiency and cost. When using pure nickel blades (such as ASP60), the die life is approximately 60,000 to 80,000 cycles. With the copper-nickel composite terminal solution of this embodiment, the blades can be made of die steel such as DC53, and the die life can be increased to 300,000 to 400,000 cycles.

[0035] This application discloses a copper-nickel composite terminal and its welding preparation process. The copper terminal is crimped with wire to solve the problems of pure nickel terminals sticking to the die and short die life. The nickel end is laser-welded to the aluminum bar to avoid the formation of brittle intermetallic compounds from direct copper-aluminum welding. By using curled claws to cover the claw mating surface and with anti-detachment head and anti-detachment tail stops on both sides for limiting positioning, reliable pre-positioning can be achieved before welding. The concave filling part matches the slotted aluminum bar, and the X-axis and Y-axis positions can be directly determined during assembly without complex tooling. The fish-scale pattern weld formed by laser welding achieves metallurgical bonding between copper and nickel, with a bonding strength of over 100N.

[0036] The above embodiments are not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solutions of the present invention are also within the protection scope of the present invention.

Claims

1. A copper-nickel composite terminal, characterized in that: The copper terminal (1) and nickel sheet (2) are initially positioned relative to each other and then welded together to form a composite part (3). The copper terminal (1) is provided with a wire pressing part (4), a notch (5), a wire pressing core part (6) and a coiling claw (11) in sequence from its free end to the composite part (3). The wire pressing part (4), the wire pressing core part (6) and the coiling claw (11) are all claw-shaped structures with wings on both sides. The nickel sheet (2) is provided with a claw mating surface (13) that is connected to the coiling claw (11) and anti-detachment head (12) and anti-detachment tail (14) located at both ends of the claw mating surface (13). The other end of the anti-detachment tail (14) is successively a leveling nickel sheet bending step (10), a nickel sheet flat plate part (7), and a concave filling part (8) that is assembled and positioned with the aluminum bar.

2. The copper-nickel composite terminal according to claim 1, characterized in that: The curling claw (11) bends from both sides of its wing to fit the claw mating surface (13). The width of the anti-detachment head (12) and the anti-detachment tail (14) is greater than the width of the claw mating surface (13). After the curling claw (11) clamps, the anti-detachment head (12) and the anti-detachment tail (14) respectively form the stop limit on both sides.

3. The copper-nickel composite terminal according to claim 2, characterized in that: The inner wall of the wing of the wire core part (6) is provided with a reinforcing rib (9), and the length extension direction of the reinforcing rib (9) is consistent with the extension direction of the wing of the wire core part (6).

4. The copper-nickel composite terminal according to claim 1, characterized in that: The notch (5) is a recessed transition between the wire sheathing part (4) and the wire core part (6).

5. The copper-nickel composite terminal according to claim 1, characterized in that: The nickel sheet bending step (10) on the nickel sheet (2) is a transition structure that is inclined towards the surface of the aluminum bar between the anti-tail (14) and the nickel sheet plate part (7). The nickel sheet plate part (7) is formed in a way that is parallel to the aluminum bar. The nickel sheet plate part (7) is connected to a concave structure that bends inward and is matched with the slot on the aluminum bar.

6. The copper-nickel composite terminal according to claim 1, characterized in that: The copper terminal (1) is made of pure copper N6 material, and the nickel sheet (2) is made of pure nickel N6-1 / 2H material with a thickness of 0.2±0.03mm. The composite part (3) connecting the copper terminal (1) and the nickel sheet (2) is connected by laser welding after being limited by the curling claw (11) and the claw mating surface (13). The laser connection area at the composite part (3) has a fish scale pattern weld.

7. The welding process for preparing the copper-nickel composite terminal according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Stamping process: Take copper terminal (1) and nickel sheet (2) respectively and stamp them. The copper terminal (1) is formed with wire pressing part (4), notch (5), wire pressing core part (6) and curling claw (11) in sequence. The nickel sheet (2) is formed with claw mating surface (13), anti-detachment head (12), anti-detachment tail (14), nickel sheet bending step (10), nickel sheet flat part (7) and concave filling part (8) in sequence. S2, punching process: punching the copper terminal (1) and nickel sheet (2) after stamping to the predetermined outer dimensions; S3, forming process: bend the wire pressing part (4), the wire pressing core part (6) and the coiling claw (11) in sequence, press the non-stripped end of the wire into the bent wire pressing part (4), press the stripped wire core into the bent wire pressing core part (6), place the claw surface (13) of the nickel sheet (2) into the coiling claw (11), the coiling claw (11) bends from both sides of the wing to the inside and covers the claw surface (13), the anti-detachment head (12) and the anti-detachment tail (14) are initially limited on both sides, and at the same time, the concave filling part (8) of the nickel sheet (2) is assembled into the slot of the aluminum bar to complete the pre-positioning of the copper terminal (1) and the nickel sheet (2); S4. Laser welding process: Laser welding is performed on the pre-positioned copper terminal (1) and nickel sheet (2) to form a composite part (3).

8. The welding process for the copper-nickel composite terminal according to claim 7, characterized in that: In the laser welding process, the peak laser welding power is 4.4~5.0KW, the pulse time is 2~5ms, the pulse frequency is 1HZ, and the composite part (3) after welding has a fish scale pattern.

9. The welding process for the copper-nickel composite terminal according to claim 7, characterized in that: The S3 forming process also includes a wire crimping process, which automatically cuts the wire and then uses the upper and lower blades of the pneumatic mold to crimp the wire sheath (4) and the wire core (6) respectively, thus completing the crimping and fixing of the wire.

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