Aluminum bond strap connecting structure and connecting method thereof

Abstract

The invention discloses an aluminum bond strap connecting structure and a connecting method thereof. The connecting method comprises the steps that the connecting end of a bond strap is subjected to surface activating treatment, a surface oxide layer is removed through laser, an activating layer is formed, and the surface of the activating layer is coated with a conducting medium to form a composite interface layer; an anti-loose structure assembly is assembled at the connecting end, and the anti-loose structure assembly comprises a self-locking gasket and a temperature compensation ring; dynamic compression joint is applied between the anti-loosening structure assembly and the connecting end, axial pressure is applied, radial micro-vibration is overlaid, and the composite interface layer generates plastic flow to form metallurgical bonding; hybrid welding is carried out on the connection structure after dynamic crimping, resistance welding is carried out in sequence to form a metal bonding layer, and bond strap connection is completed through ultrasonic welding; contact resistance is effectively eliminated through laser activation and conducting medium coating, the interface bonding strength is improved through the dynamic crimping technology, the porosity is reduced through composite welding, ultra-stable electric connection of the aluminum bond strap in a high-vibration environment is achieved through combination, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of connecting devices, and in particular to an aluminum grounding wire connecting structure and a connecting method thereof. Background Art

[0002] In the field of electrical connectors, aluminum conductors, due to their lightweight and cost-effectiveness, are widely used in conductive terminal connections across various electrical devices. They play a crucial role in connectors, terminal blocks, and current collectors that transmit current or provide electrical continuity. These connectors are commonly exposed to plug-in and unplug cycles, mechanical vibration, and ambient temperature fluctuations in practical applications (such as vehicle wiring harnesses, industrial control cabinet connections, and power supply interfaces for removable devices). These challenges severely impact the dynamic contact stability and long-term conductivity reliability of the terminal connections.

[0003] The oxide layer that easily forms on aluminum surfaces significantly increases contact resistance, while the inherent micromotion phenomenon (small relative movements at the contact interface caused by vibration or thermal cycling) inherent in connector use accelerates contact surface degradation. Existing techniques often connect aluminum conductors to connector terminals using a combination of mechanical crimping and soldering. For example, a crimping tool applies static pressure to plastically deform the conductor and terminal metal, achieving physical engagement, and then tin-based solder is applied to fill the interfacial gap. However, this method has significant drawbacks under dynamic conditions: the metal interface formed by static crimping is susceptible to microscopic slip and wear under continuous micromotion, leading to unstable or even gradual contact resistance increases. Furthermore, the mismatch in the coefficient of thermal expansion (CTE) between the solder layer and the aluminum substrate generates interfacial stresses under temperature fluctuations, inducing crack initiation and propagation in the solder layer, ultimately leading to electrical connection failure, excessive contact impedance, and even the risk of overheating. This technical bottleneck limits the use of aluminum conductors in applications requiring high-reliability connections, such as automotive electronics and aerospace connectors, and increases the maintenance requirements of the connector system.

[0004] In view of this, it is necessary to improve the connection technology between aluminum wires and connector terminals in the existing technology to solve the technical problem that the reliability of electrical connection is easily reduced under vibration conditions. Summary of the Invention

[0005] The object of the present invention is to provide an aluminum grounding wire connection structure and a connection method thereof to solve the above technical problems.

[0006] To achieve this object, the present invention adopts the following technical solutions: A method for connecting an aluminum grounding wire connection structure, comprising: Step S1, performing surface activation treatment on the connecting end of the ground wire, specifically using laser to remove the surface oxide layer and form an activation layer with a preset roughness, and coating the surface of the activation layer with a conductive medium to form a composite interface layer; Step S2, assembling an anti-loosening structure component on the surface-activated connection end, wherein the anti-loosening structure component includes a self-locking washer and a temperature compensation ring, and the conical surface of the self-locking washer is matched with the conical structure of the connection end; Step S3, applying dynamic compression between the anti-loosening structural component and the connecting end, applying axial pressure and superimposing radial micro-vibration by a servo press, so as to cause the composite interface layer to generate plastic flow and form a metallurgical bond; Step S4, performing composite welding on the connection structure after dynamic pressing, performing resistance welding in sequence to form a metal bonding layer, and then performing ultrasonic welding to fill the microscopic pores to complete the densification process and complete the grounding wire connection.

[0007] Optionally, the conductive medium is any one of the following: Nano-metal particle composite material, including 60%-75% by mass of nano-silver particles and epoxy resin matrix; Conductive polymer material, composed of polypyrrole and carbon nanotubes in a mass ratio of 1:0.2-0.5.

[0008] Optionally, the specific process of coating the conductive medium on the surface of the activation layer to form the composite interface layer includes: S101, performing surface pretreatment on the activation layer using an acid solution; S102, mixing the conductive medium and the diluent in a ratio of 1:0.3-0.8 to prepare a coating slurry of a preset viscosity; S103, applying the slurry to the surface of the activation layer by spraying or dipping, and controlling the thickness of a single coating to be within a preset range; S104, thermally curing at 80-120°C for 30-90 minutes to chemically bond the conductive medium to the activation layer to form a composite interface layer; S105 , applying pre-pressure to the solidified composite interface layer to perform densification treatment, and finally forming a composite interface layer with a qualified porosity.

[0009] Optionally, the temperature compensation ring is a multi-layer corrugated structure formed by stamping a copper-aluminum composite sheet; The contact surface between the self-locking washer and the temperature compensation ring is provided with radial micro-groove structures that mesh with each other, and the groove spacing and the self-locking washer locking tooth spacing are distributed in a ratio of 1:2.

[0010] Optionally, step S3 specifically includes the following steps: S31, based on the thickness of the composite interface layer and the roughness of the activation layer, set the axial reference pressure value P0 and the radial vibration frequency f0 of the servo press, where P0 = 180~220N, f0 = 1~5Hz; S32, applying axial pre-compression to the anti-loosening structure assembly, using an initial pressure of 0.5P0 to initially engage the conical surface of the self-locking washer with the conical structure of the connection end, thereby forming an initial mechanically interlocked bonding layer; S33 , while maintaining the axial pressure P0 , start the radial micro-vibration module to apply a swing with a preset amplitude along the circumference of the connection end, forcing the composite interface layer to generate shear plastic deformation.

[0011] Optionally, after step S33, the following steps may be further performed: S34, real-time monitoring of the interface contact resistance value R, when R ≤ 0.5 mΩ, dynamically adjusting the axial pressure according to the adjustment value ΔP = K (R - R0), where K is the pressure compensation coefficient and R0 is the target resistance threshold; S35, after the plastic deformation reaches the stable stage, the gradient pressure strategy is implemented: the axial pressure is increased to 1.2P0 at a rate of 10N / s and maintained for 30-60 seconds to promote dynamic recrystallization of the interface metal grains; S36: Turn off radial vibration and gradually remove axial pressure. Use an infrared thermal imager to detect the uniformity of interface temperature distribution and confirm that there are no local overheating areas in the metallurgical bonding layer.

[0012] Optionally, step S4 specifically includes the following steps: S41, based on the grain size distribution of the metallurgical bonding layer, set the initial resistance welding current I1 = 8-12 kA and the power-on time t1 = 10-20 ms, and simultaneously preheat the vibration frequency of the ultrasonic welding head to 18-22 kHz; S42, arranging three groups of resistance welding electrodes equidistantly along the circumference of the connection end, applying a current I1 to locally heat the interface to 380-420°C, and forming a CuAl2 metal bonding layer of a first thickness; S43, use an eddy current detector to scan the bonding layer, mark the area with porosity greater than 5% as the repair area, and generate a pore distribution thermal map; S44, adjusting the amplitude of the ultrasonic welding head according to the pore distribution thermodynamic map, applying a preset axial pressure to the repair welding area, and filling the pores to a target porosity through high-frequency vibration; S45, covering the surface of the ultrasonic welding area with a coolant, performing gradient cooling at a cooling rate of 20-30°C / s, and obtaining a densified connection structure.

[0013] Optionally, after step S4, the following steps may be further performed: Step S5 , performing a sealing test on the ground wire connection structure, encapsulating the connection part with a heat shrink tubing and injecting an insulating sealing material, and verifying the integrity of the conductive path through a constant current test.

[0014] Optionally, step S5 specifically includes the following steps: S51, heat shrink tubing is evenly spaced along the circumference of the connection structure, and shrinkage is triggered in sequence by heating in stages: first, heating to 80-100°C at a rate of 5-10°C / s to complete pre-shrinkage, and then gradually increasing the temperature to 130-150°C to achieve full-diameter tight wrapping; S52, injecting insulating sealing material into the gap of the heat shrink tubing through a multi-point syringe; S53, curing the sealing material under ultraviolet light irradiation, and simultaneously applying a radial pressure of 0.3-0.8 MPa to eliminate interface bubbles; S54, perform constant current detection verification: apply a constant current of 100mA and collect 10 sets of voltage samples, calculate the resistance dispersion coefficient and determine whether the conductive path is qualified according to the preset standard.

[0015] The present invention further provides an aluminum grounding wire connection structure, which is manufactured using the connection method of the aluminum grounding wire connection structure described above. The aluminum grounding wire structure specifically includes a grounding wire body, the grounding wire body having a connection end, and the connection end is formed with a composite interface layer; The connection end is provided with an anti-loosening structural component, and the anti-loosening structural component includes a self-locking washer and a temperature compensation ring; A composite welding layer is provided between the connection end and the anti-loosening structural component. The composite welding layer includes a metal bonding layer formed by resistance welding and a densification layer formed by ultrasonic welding.

[0016] Compared with the existing technology, the present invention has the following beneficial effects: first, the oxide layer at the connection end of the grounding wire is removed by laser surface activation treatment and a composite interface layer is constructed; then, an anti-loosening structural component with a self-locking washer and a temperature compensation ring is assembled; and then a servo press is used to apply axial pressure and radial micro-vibration to achieve metallurgical bonding of the composite interface layer; and the densification treatment of the connection structure is completed through a composite process of resistance welding and ultrasonic welding to form a grounding wire connection system with high stability; this process effectively eliminates contact resistance through laser activation and conductive medium coating, the dynamic crimping process improves the interface bonding strength, and the composite welding reduces the porosity. The combination realizes ultra-stable electrical connection of the aluminum grounding wire in a high vibration environment, thereby improving the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] The structures, proportions, sizes, etc. depicted in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not intended to limit the conditions under which the present invention can be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportional relationships, or adjustments in size should still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and objectives that can be achieved by the present invention.

[0019] Figure 1 This is a flow chart of a connection method for the aluminum grounding wire connection structure according to the first embodiment of the present invention; Figure 2 This is a second flow chart of the connection method of the aluminum grounding wire connection structure of the first embodiment; Figure 3 This is the third flow chart of the connection method of the aluminum grounding wire connection structure of the first embodiment.

[0020] Figure 4 This is a schematic diagram of the main structure of the aluminum grounding wire connection structure of the first embodiment. DETAILED DESCRIPTION

[0021] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They are not intended to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. It should be noted that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally located component.

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0024] Example 1: Combine Figures 1 to 3 As shown, an embodiment of the present invention provides a connection method for an aluminum grounding wire connection structure, comprising: Step S1, performing surface activation treatment on the connecting end of the ground wire, specifically using laser to remove the surface oxide layer and form an activation layer with a preset roughness, and coating the surface of the activation layer with a conductive medium to form a composite interface layer; Laser surface activation removes the oxide layer from the aluminum ground wire connection, creating an activated surface with a specific roughness and enhancing the substrate's surface activity. A conductive dielectric is then applied to form a composite interface layer, enhancing electrical contact performance and inhibiting oxidation regeneration. This synergistic physical and chemical modification creates a low-resistance, highly stable contact interface for subsequent mechanical connection.

[0025] Step S2: Assembling a locking mechanism assembly onto the surface-activated connection end. This assembly includes a self-locking washer and a temperature compensation ring. The self-locking washer's tapered surface matches the tapered structure of the connection end. In the assembled locking mechanism, the self-locking washer's tapered surface provides mechanical self-locking, preventing loosening under vibration conditions. The temperature compensation ring utilizes a copper-aluminum composite corrugated structure to match the thermal expansion characteristics of the aluminum substrate, reducing the impact of thermal stress on the connection interface. The meshing structure of the two elements synergizes to achieve a balance between mechanical locking and thermal stability, enhancing connection reliability under complex operating conditions.

[0026] In step S3, dynamic compression is applied between the anti-loosening structural component and the connection end. A servo press applies axial pressure and superimposed radial micro-vibration, causing plastic flow in the composite interface layer to form a metallurgical bond. The dynamic compression process, through a combined loading method of axial pressure and radial micro-vibration, promotes plastic flow and lattice reconstruction in the composite interface layer, forming a metallurgical bond. This process overcomes the stress concentration drawback of traditional static compression, achieving diffusion bonding of metal atoms at the interface through dynamic energy input, significantly improving joint strength and fatigue resistance.

[0027] Step S4, performing composite welding on the connection structure after dynamic pressing, performing resistance welding in sequence to form a metal bonding layer, and then performing ultrasonic welding to fill the microscopic pores to complete the densification process and complete the grounding wire connection.

[0028] Resistance welding forms a metal bonding layer (such as CuAl2) at the interface, establishing a high-strength conductive path. Ultrasonic welding then uses high-frequency vibrations to fill microscopic pores and eliminate interface defects. The sequential synergy of these two welding processes balances macroscopic bond strength with microscopic density, achieving simultaneous optimization of electrical and mechanical performance.

[0029] In step S5, a seal test is performed on the ground wire connection structure. The connection is encapsulated with heat shrink tubing and filled with insulating sealing material. Constant current testing is used to verify the integrity of the conductive path. The heat shrink tubing and insulating sealing material provide physical protection from the environment, preventing the intrusion of moisture and corrosive media. Constant current testing verifies the integrity of the conductive path and ensures that the connection resistance meets design requirements.

[0030] The working principle of the present invention is: first, the oxide layer at the connection end of the grounding wire is removed through laser surface activation treatment and a composite interface layer is constructed; then, an anti-loosening structural component with a self-locking washer and a temperature compensation ring is assembled; and then a servo press is used to apply axial pressure and radial micro-vibration to achieve metallurgical bonding of the composite interface layer; and the densification treatment of the connection structure is completed through a composite process of resistance welding and ultrasonic welding to form a grounding wire connection system with high stability; this process effectively eliminates contact resistance through laser activation and conductive medium coating, the dynamic crimping process improves the interface bonding strength, and the composite welding reduces the porosity. The combination realizes ultra-stable electrical connection of the aluminum grounding wire in a high vibration environment, thereby improving the service life.

[0031] In this embodiment, the conductive medium is any of the following: Nano-metal particle composite materials include 60%-75% nano-silver particles and an epoxy resin matrix; the high conductivity of the silver particles and the adhesion of the resin synergistically improve the interfacial conductive stability.

[0032] The conductive polymer material is composed of polypyrrole and carbon nanotubes in a mass ratio of 1:0.2-0.5; the conductive enhancement effect of carbon nanotubes and the flexibility of polypyrrole are used to achieve interface adaptive contact.

[0033] In this embodiment, it is specifically described that the specific process of coating the conductive medium on the surface of the activation layer to form the composite interface layer includes: S101, using an acid solution to pre-treat the surface of the activation layer; the acid solution pre-treatment removes residual oxides (such as Al2O3) on the surface of the activation layer through chemical corrosion, while increasing the surface hydroxyl (-OH) density, enhancing the chemical bonding ability between the conductive medium and the aluminum substrate, and providing a highly active base surface for subsequent coating.

[0034] S102, mixing the conductive medium and the diluent in a ratio of 1:0.3-0.8 to prepare a coating slurry with a preset viscosity; regulating the rheological properties of the slurry (such as viscosity and thixotropy) by the diluent ratio so that the conductive medium forms a uniformly dispersed coating slurry, ensuring that a uniform covering layer without bubbles and stratification is formed during the coating process, and avoiding fluctuations in interface performance caused by local accumulation or loss.

[0035] S103, the slurry is applied to the surface of the activation layer by spraying or dipping, and the thickness of a single coating is controlled within a preset range; the spraying process is suitable for uniform coating on complex geometric surfaces, while the dipping process achieves deep penetration and filling; the thickness of a single coating is controlled (e.g., 10-30μm) to match the roughness of the activation layer to ensure that the conductive medium and the aluminum substrate form an effective mechanical interlocking structure.

[0036] S104, thermally cure at 80-120°C for 30-90 minutes to chemically bond the conductive medium to the activation layer, forming a composite interface layer; the thermal curing process promotes the cross-linking reaction of the epoxy resin or the reconstruction of the polymer chain, so that the conductive medium and the aluminum matrix are stably bonded through chemical bonds (such as Si-O-Al). The curing temperature and duration are precisely matched according to the thermal stability of the material (such as the glass transition temperature of the epoxy resin) to avoid thermal decomposition or interface embrittlement.

[0037] S105 applies pre-compression to the cured composite interface layer for densification, ultimately forming a composite interface layer with acceptable porosity. Mechanical pressure densification eliminates micropores formed during the curing process (such as resin shrinkage pores) through plastic deformation, increasing the density of the interface layer and ensuring that the conductive particles form a continuous network, thereby reducing contact resistance and improving resistance to environmental corrosion.

[0038] In this embodiment, the temperature compensation ring is a multi-layer corrugated structure, which is formed by stamping a copper-aluminum composite sheet; the contact surface between the self-locking washer and the temperature compensation ring is provided with a radial micro-groove structure that meshes with each other, and the groove spacing and the self-locking washer locking tooth spacing are distributed in a ratio of 1:2.

[0039] It should be noted that the temperature compensation ring adopts a multi-layer corrugated structure stamped from copper-aluminum composite sheets. The conductive path is optimized through the copper layer (15%-20%), the aluminum matrix matches the thermal expansion characteristics of the grounding wire, and the corrugated design provides axial expansion compensation capabilities; the radial micro-groove structure of the contact surface between the self-locking washer and the temperature compensation ring (the ratio of the groove spacing to the locking tooth spacing is 1:2) forms a mechanical-thermal dual-mode interlocking, which not only enhances the vibration resistance, but also optimizes the contact stress distribution through groove spacing matching, solving the problem of connection failure under the coupling of thermal cycling and vibration.

[0040] In this embodiment, it is specifically explained that step S3 specifically includes the following steps: S31, based on the thickness of the composite interface layer and the roughness of the activation layer, set the axial reference pressure value P0 and the radial vibration frequency f0 of the servo press, where P0 = 180~220N, f0 = 1~5Hz; The axial pressure (180-220N) and vibration frequency (1-5Hz) are set based on the thickness and surface roughness of the composite interface layer to ensure that the dynamic pressing parameters are adapted to the interface characteristics, avoiding insufficient bonding due to insufficient pressure or substrate damage caused by pressure overload.

[0041] S32, applying axial pre-compression to the anti-loosening structural component, using an initial pressure of 0.5P0 to initially engage the conical surface of the self-locking washer with the conical structure of the connection end, thereby forming an initial mechanically interlocked bonding layer; Through pre-compression welding with 0.5 times the reference pressure, the conical surface of the self-locking washer and the conical structure of the connection end are initially engaged to form an initial bonding layer of mechanical interlocking, which provides a stable mechanical basis for subsequent dynamic loading and prevents interface slip during vibration.

[0042] S33 , while maintaining the axial pressure P0 , start the radial micro-vibration module to apply a swing with a preset amplitude along the circumference of the connection end, forcing the composite interface layer to generate shear plastic deformation.

[0043] By superimposing circumferential micro-vibration (amplitude 0.3-0.8mm) while maintaining axial pressure, shear stress is used to force the composite interface layer to undergo plastic flow, destroying the surface oxide film and promoting the diffusion of metal atoms, thus realizing the transformation of the interface from mechanical biting to metallurgical bonding.

[0044] S34, real-time monitoring of the interface contact resistance value R. When R ≤ 0.5 mΩ, dynamically adjust the axial pressure according to the adjustment value ΔP = K·(R-R0), where K is the pressure compensation coefficient (0.5-1.2 N / mΩ) and R0 is the target resistance threshold; By real-time monitoring of contact resistance and dynamic adjustment of pressure (ΔP=K·(R-R0)), a feedback closed loop between process parameters and electrical performance is established, and the interface bonding state is adaptively optimized to ensure that the contact resistance stably approaches the target threshold (R0=0.35mΩ).

[0045] S35, after the plastic deformation reaches the stable stage, the gradient pressure strategy is implemented: the axial pressure is increased to 1.2P0 at a rate of 10N / s and maintained for 30-60 seconds to promote dynamic recrystallization of the interface metal grains; The gradient pressurization strategy (10N / s to 1.2P0) induces dynamic recrystallization of the interface metal, refines the grains and eliminates work hardening, improves the toughness and fatigue resistance of the metallurgical bonding layer, and maintains it for 30-60 seconds to fully complete the recrystallization process.

[0046] S36: Turn off radial vibration and gradually remove axial pressure. Use an infrared thermal imager to detect the uniformity of interface temperature distribution and confirm that there are no local overheating areas in the metallurgical bonding layer.

[0047] By analyzing the uniformity of interface temperature distribution (temperature difference ≤ 15°C) through infrared thermal imaging, it is verified that there is no local overheating or unbonded defects in the metallurgical bonding layer, ensuring the homogeneity and reliability of the interface microstructure and providing a qualified matrix for subsequent welding processes.

[0048] In this embodiment, it is specifically explained that step S4 specifically includes the following steps: S41, based on the grain size distribution of the metallurgical bonding layer, set the initial resistance welding current I1 = 8-12 kA and the power-on time t1 = 10-20 ms, and simultaneously preheat the vibration frequency of the ultrasonic welding head to 18-22 kHz; The resistance welding parameters (8-12kA / 10-20ms) are set based on the grain size distribution of the metallurgical bonding layer to ensure that the welding heat input is compatible with the interface microstructure; the ultrasonic welding head is simultaneously preheated to a vibration frequency of 18-22kHz to reduce the time difference in process switching and provide a synergistic basis for composite welding.

[0049] S42, arranging three groups of resistance welding electrodes equidistantly along the circumference of the connection end, applying a current I1 to locally heat the interface to 380-420°C, and forming a CuAl2 metal bonding layer of a first thickness; The resistance welding electrodes (3 groups) are arranged equidistantly around the periphery to achieve uniform heat field distribution. The Joule heating effect causes the interface to be locally heated to below the Al-Cu eutectic temperature (380-420°C), forming a CuAl2 metal bonding layer with controllable thickness, which takes into account both electrical conductivity and interface bonding strength.

[0050] S43, use an eddy current detector to scan the bonding layer, mark the area with porosity greater than 5% as the repair area, and generate a pore distribution thermal map; Eddy current testing uses the principle of electromagnetic induction to identify porosity defects in the bonding layer, generate a pore distribution heat map, locate high-risk areas with porosity greater than 5%, and provide precise spatial coordinates for directional repair welding.

[0051] S44, adjusting the amplitude of the ultrasonic welding head according to the pore distribution thermodynamic map, applying a preset axial pressure to the repair welding area, and filling the pores to the target porosity through high-frequency vibration; The ultrasonic amplitude and axial pressure (50-80N) are dynamically adjusted according to the pore distribution thermodynamic map, and the "hammer effect" of high-frequency vibration is used to fill the pores to a porosity of ≤0.8%, eliminating the discontinuity of the interface conductive path.

[0052] S45, covering the surface of the ultrasonic welding area with a coolant, performing gradient cooling at a cooling rate of 20-30°C / s, and obtaining a densified connection structure.

[0053] Gradient cooling (20-30°C / s) refines the grains and reduces residual stress by controlling the phase transformation process, avoiding interfacial brittle cracks caused by rapid cooling, and making the densified connection structure have both high toughness and stability.

[0054] In this embodiment, it is specifically explained that step S5 specifically includes the following steps: S51, heat shrink tubing is evenly spaced along the circumference of the connection structure, and shrinkage is triggered in sequence by heating in stages: first, heating to 80-100°C at a rate of 5-10°C / s to complete pre-shrinkage, and then gradually increasing the temperature to 130-150°C to achieve full-diameter tight wrapping; The segmented heating process achieves gradient shrinkage of the heat shrink tubing by controlling the heating rate (5-10℃ / s). The pre-shrinkage stage (80-100℃) eliminates internal stress in the material and avoids local wrinkles. The full-diameter shrinkage stage (130-150℃) ensures a close fit between the tubing and the connection structure, forming a uniform wrapping layer, thereby improving the sealing, waterproofing and mechanical protection effects.

[0055] S52, inject insulating sealing material into the gap of the heat shrink tubing through a multi-point syringe; the injection pressure is controlled at 0.2-0.5MPa, and the filling is carried out in three steps and the filling volume is monitored in real time to achieve a rate of ≥95%.

[0056] Use a multi-point syringe to inject insulating sealing materials (such as silicone) in three steps. Through pressure control (0.2-0.5MPa) and volume achievement rate monitoring (≥95%), ensure that the sealing material fully fills the sleeve gap, avoid local insulation failure caused by residual bubbles or insufficient filling, and enhance environmental isolation performance.

[0057] S53, cures the sealing material under ultraviolet light, and simultaneously applies 0.3-0.8MPa radial pressure to eliminate interface bubbles; UV curing triggers a rapid cross-linking reaction of the sealing material, and simultaneously applies radial pressure (0.3-0.8MPa) to force the interface bubbles to escape and compact the sealing layer, forming a dense protective structure without pores, thereby improving resistance to moisture penetration and aging.

[0058] S54, perform constant current testing and verification: Apply a constant current of 100mA and collect 10 sets of voltage samples. The resistance dispersion coefficient is calculated and used to determine whether the conductive path is qualified according to preset standards. Constant current testing verifies the integrity of the conductive path by applying a 100mA current and analyzing the dispersion coefficient of the voltage samples (reflecting resistance uniformity). This ensures that the connection structure is free of localized contact problems or short circuit risks, meeting the electrical safety requirements of industrial equipment.

[0059] Example 2: Combine Figure 4 As shown, the present invention further provides an aluminum grounding wire connection structure, which is manufactured using the connection method of the aluminum grounding wire connection structure as in Example 1. The aluminum grounding wire structure specifically includes a grounding wire body 10, the grounding wire body having a connection end 11, and the connection end is formed with a composite interface layer 12; The connection end 11 is provided with an anti-loosening structural component 20, which includes a self-locking washer 21 and a temperature compensation ring 22; A composite welding layer is provided between the connection end 11 and the anti-loosening structural component 20 , and the composite welding layer includes a metal bonding layer formed by resistance welding and a densification layer formed by ultrasonic welding.

[0060] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for connecting an aluminum grounding wire connection structure, characterized in that: include: Step S1, performing surface activation treatment on the connecting end of the ground wire, specifically using laser to remove the surface oxide layer and form an activation layer with a preset roughness, and coating the surface of the activation layer with a conductive medium to form a composite interface layer; Step S2, assembling an anti-loosening structure component on the surface-activated connection end, wherein the anti-loosening structure component includes a self-locking washer and a temperature compensation ring, and the conical surface of the self-locking washer is matched with the conical structure of the connection end; Step S3, applying dynamic compression between the anti-loosening structural component and the connecting end, applying axial pressure and superimposing radial micro-vibration by a servo press, so as to cause the composite interface layer to generate plastic flow and form a metallurgical bond; Step S4, performing composite welding on the connection structure after dynamic pressing, performing resistance welding in sequence to form a metal bonding layer, and then performing ultrasonic welding to fill the microscopic pores to complete the densification process and complete the grounding wire connection.

2. The connection method of the aluminum grounding wire connection structure according to claim 1, characterized in that: The conductive medium is any one of the following: Nano-metal particle composite material, including 60%-75% by mass of nano-silver particles and epoxy resin matrix; Conductive polymer material, composed of polypyrrole and carbon nanotubes in a mass ratio of 1:0.2-0.

5.

3. The connection method of the aluminum grounding wire connection structure according to claim 1, characterized in that: The specific process of coating the conductive medium on the surface of the activation layer to form a composite interface layer includes: S101, performing surface pretreatment on the activation layer using an acid solution; S102, mixing the conductive medium and the diluent in a ratio of 1:0.3-0.8 to prepare a coating slurry of a preset viscosity; S103, applying the slurry to the surface of the activation layer by spraying or dipping, and controlling the thickness of a single coating to be within a preset range; S104, thermally curing at 80-120°C for 30-90 minutes to chemically bond the conductive medium to the activation layer to form a composite interface layer; S105 , applying pre-pressure to the solidified composite interface layer to perform densification treatment, and finally forming a composite interface layer with a qualified porosity.

4. The connection method of the aluminum grounding wire connection structure according to claim 1, characterized in that: The temperature compensation ring is a multi-layer corrugated structure, formed by stamping copper-aluminum composite sheets; The contact surface between the self-locking washer and the temperature compensation ring is provided with radial micro-groove structures that mesh with each other, and the groove spacing and the self-locking washer locking tooth spacing are distributed in a ratio of 1:

2.

5. The connection method of the aluminum grounding wire connection structure according to claim 1, characterized in that: The step S3 specifically includes the following steps: S31, based on the thickness of the composite interface layer and the roughness of the activation layer, set the axial reference pressure value P0 and the radial vibration frequency f0 of the servo press, where P0 = 180~220N, f0 = 1~5Hz; S32, applying axial pre-compression to the anti-loosening structure assembly, using an initial pressure of 0.5P0 to initially engage the conical surface of the self-locking washer with the conical structure of the connection end, thereby forming an initial mechanically interlocked bonding layer; S33 , while maintaining the axial pressure P0 , start the radial micro-vibration module to apply a swing with a preset amplitude along the circumference of the connection end, forcing the composite interface layer to generate shear plastic deformation.

6. The connection method of the aluminum grounding wire connection structure according to claim 1, characterized in that: After step S33, the following steps are further included: S34, real-time monitoring of the interface contact resistance value R, when R ≤ 0.5 mΩ, dynamically adjusting the axial pressure according to the adjustment value ΔP = K (R - R0), where K is the pressure compensation coefficient and R0 is the target resistance threshold; S35, after the plastic deformation reaches the stable stage, the gradient pressure strategy is implemented: the axial pressure is increased to 1.2P0 at a rate of 10N / s and maintained for 30-60 seconds to promote dynamic recrystallization of the interface metal grains; S36: Turn off radial vibration and gradually remove axial pressure. Use an infrared thermal imager to detect the uniformity of interface temperature distribution and confirm that there are no local overheating areas in the metallurgical bonding layer.

7. The connection method of the aluminum grounding wire connection structure according to claim 1, characterized in that: The step S4 specifically includes the following steps: S41, based on the grain size distribution of the metallurgical bonding layer, set the initial resistance welding current I1 = 8-12 kA and the power-on time t1 = 10-20 ms, and simultaneously preheat the vibration frequency of the ultrasonic welding head to 18-22 kHz; S42, arranging three groups of resistance welding electrodes equidistantly along the circumference of the connection end, applying a current I1 to locally heat the interface to 380-420°C, and forming a CuAl2 metal bonding layer of a first thickness; S43, use an eddy current detector to scan the bonding layer, mark the area with porosity greater than 5% as the repair area, and generate a pore distribution thermal map; S44, adjusting the amplitude of the ultrasonic welding head according to the pore distribution thermodynamic map, applying a preset axial pressure to the repair welding area, and filling the pores to a target porosity through high-frequency vibration; S45, covering the surface of the ultrasonic welding area with a coolant, performing gradient cooling at a cooling rate of 20-30°C / s, and obtaining a densified connection structure.

8. The connection method of the aluminum grounding wire connection structure according to claim 1, characterized in that: After step S4, the following steps are also included: Step S5 , performing a sealing test on the ground wire connection structure, encapsulating the connection part with a heat shrink tubing and injecting an insulating sealing material, and verifying the integrity of the conductive path through a constant current test.

9. The connection method of the aluminum grounding wire connection structure according to claim 8, characterized in that: The step S5 specifically includes the following steps: S51, heat shrink tubing is evenly spaced along the circumference of the connection structure, and shrinkage is triggered in sequence by heating in stages: first, heating to 80-100°C at a rate of 5-10°C / s to complete pre-shrinkage, and then gradually increasing the temperature to 130-150°C to achieve full-diameter tight wrapping; S52, injecting insulating sealing material into the gap of the heat shrink tubing through a multi-point syringe; S53, curing the sealing material under ultraviolet light irradiation, and simultaneously applying a radial pressure of 0.3-0.8 MPa to eliminate interface bubbles; S54, perform constant current detection verification: apply a constant current of 100mA and collect 10 sets of voltage samples, calculate the resistance dispersion coefficient and determine whether the conductive path is qualified according to the preset standard.

10. An aluminum grounding wire connection structure, characterized in that: The aluminum grounding wire connection structure is manufactured by the connection method according to any one of claims 1 to 9, wherein the aluminum grounding wire structure specifically comprises a grounding wire body, the grounding wire body has a connection end, and the connection end is formed with a composite interface layer; The connection end is provided with an anti-loosening structural component, and the anti-loosening structural component includes a self-locking washer and a temperature compensation ring; A composite welding layer is provided between the connection end and the anti-loosening structural component. The composite welding layer includes a metal bonding layer formed by resistance welding and a densification layer formed by ultrasonic welding.

Images