Motor copper foil outgoing line structure and welding method thereof

Abstract

The invention relates to the technical field of copper foil welding, in particular to a motor copper foil outgoing line structure and a welding method thereof. The motor copper foil leading-out wire structure is formed by welding the copper foil winding leading-out wire, the contact area of the copper foil and the leading-out wire is large, gaps of the leading-out wire and a copper foil lap joint area are evenly filled with welding flux, firm and closed welding spots are formed, the strength of the welding spots is high, no welding seam exists on the outer side of the copper foil, the structural appearance flatness is good, and the slot fullness rate after winding of a winding is high. The invention further provides a welding method of the motor copper foil lead-out wire structure, welding of the motor copper foil lead-out wire structure is achieved through the steps of winding and wrapping the lead-out wire with the copper foil, pre-pressing forming, high-temperature welding and the like, the contact area of the copper foil and the lead-out wire is increased, the welding sectional area is larger than the sectional area of the copper foil, current conduction short plates are reduced, and the service life of the motor copper foil lead-out wire structure is prolonged. And the pressurizing level during welding is reduced by utilizing a pre-pressing forming means, the structure flatness is ensured, the welding parameters are accurately controlled, the welding process can be quickly and stably completed, and the structure quality is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of copper foil welding, and particularly to a structure of a copper foil lead-out wire for a motor and a welding method thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry, higher requirements are put forward for the power density and performance of drive motors.

[0003] A motor with high power density can provide a greater power output with a smaller volume and weight, thereby improving the performance, endurance and energy efficiency of the vehicle. Using copper foil as the armature coil material is one of the important means to improve the performance of the motor. Copper foil has excellent electrical conductivity and relatively high mechanical strength, which can significantly increase the slot fill factor of the motor, thereby further improving the power density and torque density.

[0004] However, copper foil also faces some technical challenges in practical applications. Since the copper foil is relatively wide and thin, its flexibility is poor and it is not convenient for twisting operations, which makes it occupy a relatively large space during the motor assembly process. In order to achieve flexibility in bending and installation, it is usually necessary to additionally weld the lead-out wire part. However, the current copper foil welding lead-out wire technology has the following problems: (1) Insufficient contact area: The contact area between the copper foil and the lead-out wire is small, resulting in insufficient current-carrying capacity. When the motor bears a high load, the current density increases, which easily causes serious heating phenomena and affects the efficiency and life of the motor; (2) Poor stability of the solder joint structure: The stability of the solder joint structure formed during the welding process is insufficient. Under working conditions of vibration or temperature fluctuations, the solder joints are prone to falling off, reducing the reliability and durability of the motor; (3) Uneven weld appearance: The weld appearance after welding is uneven in height and the transition with the copper foil is not smooth, which will affect the winding forming of the armature coil and increase the manufacturing difficulty and cost of the winding; (4) Copper foil deformation: The copper foil may be deformed or burned through during the welding process, which will not only affect the dimensional accuracy of the armature coil winding forming, but also lead to insufficient solder joint strength and reduce the overall performance of the motor.

[0005] In summary, although copper foil has significant advantages in improving the performance of the motor, its welding lead-out wire technology is still a problem that needs to be optimized and solved by those skilled in the art in order to better meet the requirements of new energy vehicles for high power density motors. Summary of the Invention

[0006] To solve the problem of how to optimize the technology of welding and leading out the copper foil of an electric motor, the present invention provides a structure of the copper foil leading-out wire of an electric motor, which is formed by winding and welding the copper foil leading-out wire; solder evenly fills the area around the leading-out wire and the overlapping area of the copper foil, and the cross-sectional area of the welding part is more than 150% of the cross-sectional area of the copper foil; wherein, one end of the leading-out wire is connected to the copper foil winding, and the other end is connected to the outgoing terminal.

[0007] In one embodiment, the thickness of the copper foil is 0.02 mm to 1 mm.

[0008] In one embodiment, the leading-out wire is a copper wire, and the specification of the copper wire is φ0.03 to φ1.1, and the number of strands ≥ 1.

[0009] It should be noted that when the number of strands of the copper wire ≥ 5, the multi-strand copper wires are arranged in a rectangular array on the surface of the copper foil. The long side of the rectangular array is parallel to the side of the copper foil, and the short side is perpendicular to the side of the copper foil; there are 2 to 4 layers of copper wires arranged on the short side of the rectangular array; the welding length in the axial direction of the leading-out wire is 70% to 100% of the width of the copper foil; the length of the overlapping area of the copper foil is 30% to 70% of the total width in the radial direction of the leading-out wire; the number of winding turns of the copper foil completely winding the leading-out wire is 1 to 3 turns.

[0010] In one embodiment, the solder is HL204 or HL205.

[0011] It should also be noted that when the structure of the copper foil leading-out wire of the electric motor is used as the incoming end and the outgoing end respectively, the leading-out wires are located on the inner and outer sides of the copper foil respectively.

[0012] The present invention also provides a welding method for the structure of the copper foil leading-out wire of the electric motor as described above, including the following steps: Clean the surface of the copper foil welding end face and the welding part of the leading-out wire; Fix the solder in the copper foil welding area; Tightly wind the leading-out wire into a bundle with the copper foil, and ensure that the overlapping part of the copper foil and the welding part of the leading-out wire are in full contact with the solder; Adopt high-temperature welding technology for welding, and ensure that the solder melts and evenly fills the gaps of the leading-out wire and the overlapping area of the copper foil.

[0013] In one embodiment, it further includes the following step: before performing high-temperature welding, pre-press and form the wound copper foil leading-out wire assembly.

[0014] In one embodiment, when cleaning the surface of the copper foil welding end face and the welding part of the leading-out wire, first use sandpaper to remove the oxide layer of the copper foil and the leading-out wire, and then rinse with acetone solution.

[0015] In one embodiment, when fixing the solder, the solder is spot-welded and fixed to the surface of the copper foil welding part by laser welding.

[0016] In one embodiment, the high-temperature welding technology is any one of resistance welding, electron beam welding, and laser welding.

[0017] Furthermore, when using resistance welding for welding, the current is 1 KA to 20 KA, the time is 50 ms to 800 ms, the welding pressure is 50 N to 1000 N, and the number of welding pulses is 1 to 10 times.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The motor copper foil lead-out wire structure provided by the present invention is formed by welding the copper foil wound lead-out wire. The contact area between the copper foil and the lead-out wire is large, the solder evenly fills the gaps of the lead-out wire and the copper foil overlapping area, and a closed solder joint is formed at the winding lap, with high welding strength. In addition, there is no weld seam on the outside of the copper foil of the motor copper foil lead-out wire structure, which does not affect the subsequent copper foil winding.

[0019] The welding method of the motor copper foil lead-out wire structure provided by the present invention obtains the motor copper foil lead-out wire structure through steps such as copper foil winding to cover the lead-out wire, pre-pressing forming, and high-temperature welding. Among them, the method of copper foil winding to cover the lead-out wire can effectively increase the contact area between the copper foil and the lead-out wire, thereby ensuring that the cross-sectional area of the welding part is larger than that of the copper foil, and avoiding the welding part becoming a short board for current conduction; further, pre-pressing and forming the wound copper foil lead-out wire assembly can reduce the applied pressure during the welding process, prevent the copper foil from deforming and burning through, ensure the overall flatness of the motor copper foil lead-out wire structure, and is beneficial to improving the slot fill factor of the motor winding; during the high-temperature welding process, accurately controlling the welding parameters ensures the rapidity and stability of the welding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is a schematic diagram of the motor copper foil lead-out wire structure provided in Embodiment 1 of the present invention; Figure 2 It is a schematic diagram of the copper foil wound lead-out wire assembly provided in Embodiment 1 of the present invention.

[0022] Reference Numerals: 10 - copper foil; 20 - lead-out wire; 30 - solder. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0025] Embodiment 1 This embodiment provides a motor copper foil lead-out wire structure, as Figure 1 shown, which is formed by welding the copper foil 10 wound around the lead-out wire 20; the solder 30 evenly fills the gaps between the copper wires and the overlapping area of the copper foil 10.

[0026] Specifically, the motor copper foil lead-out wire structure is obtained by welding according to the following steps: S100. First, use sandpaper to remove the oxide layers on the copper foil and the lead-out wire, and then rinse and clean the welding surface of the copper foil and the welding part surface of the lead-out wire with acetone solution until it is ensured that there are no stains, oxide layers, and burrs. S101. Use laser welding to spot-weld and fix the solder on the surface of the copper foil welding part. S102. As Figure 2 shown, tightly wind the lead-out wire into a bundle with the copper foil. The copper foil completely winds around the lead-out wire for one turn, and it is ensured that both the overlapping part of the copper foil and the welding part of the lead-out wire are in full contact with the solder. S103. Pre-press the wound copper foil lead-out wire assembly to ensure its stable form during the welding process. S104. Use resistance welding technology for welding, and ensure that the solder melts and evenly fills the gaps between the lead-out wires and the overlapping area of the copper foil.

[0027] In this embodiment, preferably, the thickness of the copper foil 10 is 0.1 mm.

[0028] In this embodiment, preferably, the lead wire 20 is a φ0.8 copper wire with 16 strands; after being welded and formed, it is arranged in a rectangular array on the surface of the copper foil 10. The long side is parallel to the side of the copper foil 10, the short side is perpendicular to the side of the copper foil 10, and there are 2 layers of copper wires arranged on the short side; the welding length in the axial direction of the copper wire is 100% of the width of the copper foil 10, and the length of the copper foil overlapping area is 50% of the total width in the radial direction of the copper wire.

[0029] In this embodiment, preferably, the solder 30 is HL204.

[0030] In this embodiment, preferably, the resistance welding parameters are: current 1 KA, time 800 ms, welding pressure 1000 N, and number of welding pulses 10 times.

[0031] Embodiment 2 This embodiment provides a motor copper foil lead wire structure formed by welding a copper foil wound lead wire; among them, when using resistance welding for welding, the welding parameters are: current 10 KA, time 600 ms, welding pressure 150 N, and number of welding pulses 5 times. The remaining materials and operation steps are the same as those in Embodiment 1.

[0032] Embodiment 3 This embodiment provides a motor copper foil lead wire structure formed by welding a copper foil wound lead wire; among them, when using resistance welding for welding, the welding parameters are: current 14 KA, time 500 ms, welding pressure 150 N, and number of welding pulses 4 times. The remaining materials and operation steps are the same as those in Embodiment 1.

[0033] Embodiment 4 This embodiment provides a motor copper foil lead wire structure formed by welding a copper foil wound lead wire; among them, when using resistance welding for welding, the welding parameters are: current 20 KA, time 50 ms, welding pressure 50 N, and number of welding pulses 1 time. The remaining materials and welding steps are the same as those in Embodiment 1.

[0034] Comparative Example 1 This comparative example provides a motor copper foil lead wire structure, which is only different from Embodiment 1 of the present invention in that: the current in the welding parameters is 22 KA and the time is 40 ms. The remaining materials, operation steps, and welding parameters are the same as those in Embodiment 1.

[0035] Comparative Example 2 This comparative example provides a motor copper foil lead wire structure, which is only different from Embodiment 1 of the present invention in that: the welding pressure in the welding parameters is 1200 N. The remaining materials, operation steps, and welding parameters are the same as those in Embodiment 1.

[0036] The drawing force test and appearance evaluation were carried out on the motor copper foil lead wire structures provided in the above Examples 1 to 4 and Comparative Examples 1 and 2, and the results were summarized in Table 1 as shown below.

[0037] Among them, the steps of the drawing force test are as follows: Clamp the copper foil and the two ends of the lead wire of the motor copper foil lead wire structure on the tensile testing machine respectively, start the tensile testing machine until the copper foil or the lead wire breaks.

[0038] Table 1 Performance test results of the motor copper foil lead wire structures provided in Examples 1 to 4 and Comparative Examples 1 and 2

[0039] According to the performance test results in Table 1, it can be seen that the motor copper foil lead wire structures provided in Examples 1 to 4 of the present invention have no problems of burn-through and deformation, high flatness of the structure appearance, high drawing force test values, which can reach up to 700 N - 800 N at most, high solder joint strength, and good structural stability; while Comparative Examples 1 and 2 are not only inferior in terms of drawing force performance, both below 100 N, but also the structural appearance is not good. In Comparative Example 1, the copper foil was burned through, and in Comparative Example 2, the overall structure was deformed with poor flatness, which is not conducive to the subsequent winding of the winding.

[0040] Although terms such as copper foil, lead wire, winding, welding forming, lapping, pre-pressing forming, high-temperature welding, laser welding, spot welding, deformation, and burn-through are used more in this article, the possibility of using other terms is not excluded. These terms are only used to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

[0041] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A copper foil lead-out wire structure for a motor, characterized in that: It is formed by winding and welding the lead-out wire (20) with the copper foil (10). The solder (30) uniformly fills the area around the lead-out wire (20) and the overlapping area of the copper foil (10).

2. The motor copper foil lead-out wire structure according to claim 1, characterized in that: The thickness of the copper foil (10) is 0.02 mm to 1 mm.

3. The motor copper foil lead-out wire structure according to claim 1, characterized in that: The lead-out wire (20) is a copper wire, and the specification of the copper wire is φ0.03 to φ1.1, and the number of strands ≥ 1.

4. The motor copper foil lead-out wire structure according to claim 1, wherein: The solder (30) is HL204 or HL205.

5. A welding method for the motor copper foil lead-out wire structure according to any one of claims 1 to 4, characterized in that, It includes the following steps: Clean the surface of the welding end face of the copper foil and the welding part of the lead-out wire. Fix the solder in the copper foil welding area. Tightly wind the lead-out wire into a bundle with the copper foil, and ensure that both the overlapping part of the copper foil and the welding part of the lead-out wire are in full contact with the solder. Adopt high-temperature welding technology for welding, and ensure that the solder melts and uniformly fills the gaps of the lead-out wire and the overlapping area of the copper foil.

6. The welding method of the motor copper foil lead-out wire structure according to claim 5, characterized in that, It also includes the following steps: Before high-temperature welding, pre-press and form the wound copper foil lead-out wire assembly.

7. The welding method of the motor copper foil lead-out wire structure according to claim 5, characterized in that: When cleaning the surface of the welding end face of the copper foil and the welding part of the lead-out wire, first use sandpaper to remove the oxide layer of the copper foil and the lead-out wire, and then rinse with acetone solution.

8. The welding method of the motor copper foil lead-out wire structure according to claim 5, characterized in that: When fixing the solder, spot-weld the solder to the surface of the copper foil welding part by laser welding.

9. The welding method of the motor copper foil lead-out wire structure according to claim 5, characterized in that: The high-temperature welding technology is any one of resistance welding, electron beam welding and laser welding.

10. The welding method of the motor copper foil lead-out wire structure according to claim 9, characterized in that: When using resistance welding for welding, the current is 1 KA to 20 KA, the time is 50 ms to 800 ms, the welding pressure is 50 N to 1000 N, and the number of welding pulses is 1 to 10 times.

Images