Ultrasonic Welded Aluminum Flat Conductor with Relief Structure
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Solution Overview
Problem
Existing electrical connection technologies in automotive applications, particularly for flat conductors and connecting parts, face challenges in achieving long-term stability and low contact resistance, especially when using aluminum as a material, which complicates connections with other metal materials and requires large conductor cross-sections.
Innovation Solution
A relief-shaped contact surface is created on the flat part, allowing for friction welding with a connecting part, such as a stranded conductor made of aluminum or copper, where the relief structure reduces the initial contact area, increasing contact pressure and facilitating a material and positive connection through ultrasonic welding, resulting in a stable and low-resistance electrical link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If aluminum is used for electrical conductors to meet high current-carrying capacity demands, then the electrical conductivity is improved, but the connection stability and contact resistance with other metallic materials deteriorate
Solution Approach 1:
The patent applies composite material principles by creating a multi-layer connection structure consisting of an aluminum flat conductor, a transition piece made of copper or copper alloy, and a connecting part. This composite structure combines the high conductivity of aluminum with the excellent connection properties of copper, resolving the contradiction between current-carrying capacity and connection stability. The transition piece acts as an intermediary that facilitates reliable metallurgical bonding between aluminum and other metallic materials while maintaining low contact resistance.
Solution Approach 2:
The transition piece serves as an intermediary element between the aluminum flat conductor and the connecting part. This mediator component enables reliable connections by providing a suitable bonding surface for metallurgical joining while being compatible with both aluminum and other metallic materials. The transition piece resolves the incompatibility issues between aluminum and certain connecting materials, ensuring stable electrical connections.
2Quantity of substance
If large conductor cross-sections are used to achieve high current-carrying capacity, then the electrical conductivity is improved, but the ease of connection with other base materials deteriorates
Solution Approach 1:
The patent segments the connection system into distinct functional components: the aluminum flat conductor for current carrying, the transition piece for material compatibility and bonding, and the connecting part for mechanical attachment. This segmentation allows each component to be optimized for its specific function, making the overall connection process easier despite the large cross-section requirements for high current capacity.
Solution Approach 2:
By using a composite structure with a transition piece, the patent enables connection of large aluminum conductors to other base materials through a standardized interface. The transition piece provides a consistent bonding surface that simplifies the connection process regardless of the aluminum conductor's cross-sectional size.
3Ease of manufacture
If conventional metallurgical connection technology is used to connect flat conductors, then the connection process is simple, but the long-term stability and low contact resistance are insufficient
Solution Approach 1:
The patent employs a composite connection structure that combines metallurgical bonding (for long-term stability) with a structured contact surface (for low contact resistance). The transition piece is metallurgically bonded to both the aluminum flat conductor and the connecting part, ensuring stable electrical and mechanical connection over time.
Solution Approach 2:
The contact surface of the flat conductor is prepared in advance with a specific structure (such as embossing or patterning) before the connection process. This preliminary action creates an optimized bonding interface that enhances both the stability and electrical properties of the connection, going beyond conventional smooth-surface metallurgical joining.
4Quantity of substance
If the contact surface area is increased to reduce contact resistance, then the electrical conductivity is improved, but the mechanical strength of the connection deteriorates
Solution Approach 1:
The patent resolves this contradiction by using a composite structure where the transition piece provides a small-area metallurgical bond for mechanical strength, while the structured contact surface on the aluminum flat conductor increases the effective electrical contact area. The combination achieves both low contact resistance and high mechanical strength.
Solution Approach 2:
The contact surface of the flat conductor is given special local quality through structuring (embossing, patterning, or other surface modifications) only in the connection zone. This localized modification increases the electrical contact area and reduces contact resistance without affecting the overall mechanical properties of the conductor or compromising the strength of the metallurgical bond.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a long-term stable and low-contact-resistance electrical connection by increasing the contact surface area and mechanical strength, optimizing the connection process to accommodate varying material densities and conductivities, thus addressing the challenges of aluminum usage in automotive applications.
Implementation Method 1
The connecting part is then placed onto this textured surface and friction-welded, particularly using ultrasonic welding
Implementation Method 2
The connecting part is then placed onto this textured surface and friction-welded, particularly using ultrasonic welding
Implementation Method 3
The surface layers of the joining partners plasticize, starting from the initial joining area. The joining area increases due to the nature of the structure and the plasticization of the joining partners within the joining zone. Plasticizing reduces the coefficient of friction
Implementation Method 4
This results in the welding energy, particularly the vibrational energy, acting only on the small contact area at the beginning of the welding process, leading to a particularly high contact pressure in this area
Data Source
Figure 1a~1c
Figure 2a~2b
Figure 3~5
AI summary
The invention relates to an electric connection between a flat part (2) and a connection part (10). The flat part (2) and the connection part (10) are arranged one over the other in an overlap region. The flat part (2) contact surface (12) facing the connection part (10) in the overlap region has a relief structure, and the flat part (2) is friction welded, in particular ultrasonic welded, to the connection part (10) via the structured contact surface (12).