Dissimilar-Metal Busbar Joint Using Butt Pressure Welding
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Solution Overview
Problem
Connecting components made of different metal materials, such as aluminum and copper, is challenging due to oxidation and deformation issues, leading to inadequate connection strength and increased resistance, especially in high-current applications, and existing methods like welding and screwing are not efficient for complex wiring structures.
Innovation Solution
A busbar unit and manufacturing method involving pressure welding of pre-welded members made of different metal materials to the end portions of a busbar, using a process where end surfaces are buttressed and welded to form a stable connection, minimizing resistance and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding or brazing is used to connect aluminum and copper components, then connection strength may be improved, but oxidation and creep deformation occur leading to insufficient connection strength in high current ranges
Solution Approach 1:
The patent introduces an intermediary substance (flux or coating) applied to the end surfaces of the aluminum busbar before pressure welding. This intermediary prevents oxidation during the connection process and facilitates reliable bonding between dissimilar metals (aluminum and copper), resolving the contradiction by enabling both strong connection and long-term reliability in high current applications.
Solution Approach 2:
The patent modifies the surface properties of the busbar end surfaces through chemical treatment or coating application, changing the physical and chemical parameters of the connection interface. This parameter change prevents oxidation and improves weldability, allowing achieving both connection strength and reliability when connecting aluminum to copper components.
2Ease of manufacture
If screwing is used as a substitution for welding, then connection is easier to implement, but resistance increases at the connection portion and screws become loose due to deformation
Solution Approach 1:
The patent replaces the mechanical screw connection system with a pressure welding system that uses controlled mechanical pressure and heat (or cold pressure welding) to create a metallurgical bond. This substitution eliminates the problems of increased resistance and loosening associated with screw connections, while maintaining ease of implementation through automated pressure welding processes.
3Strength
If traditional welding methods are used for complex three-dimensional wiring structures, then connection strength is achieved, but flexibility to meet complex wiring demands is reduced
Solution Approach 1:
The patent segments the welding process into a standardized pressure welding operation that can be applied uniformly to various busbar configurations. By standardizing the connection method while allowing busbar geometry to vary, the system maintains connection strength across different applications while gaining flexibility to accommodate complex three-dimensional wiring structures.
Solution Approach 2:
The pressure welding method serves as a universal connection technique that can be applied to various busbar shapes, sizes, and material combinations (aluminum-aluminum, aluminum-copper, copper-copper). This universality provides both consistent connection strength and the adaptability needed for complex wiring structures with diverse geometric requirements.
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
This approach provides a strong, stable connection with minimal resistance and allows for the creation of complex wiring structures, effectively addressing the limitations of traditional welding and screwing methods by ensuring sufficient connection strength and flexibility in connecting dissimilar metal components.
Implementation Method 1
A welded portion between the end portion and the second metal material is configured by pressure welding with end surfaces butted against each other
Data Source
AI summary
Provided are a busbar unit and a method of manufacturing thereof configured to prevent an increase in resistance at a connection portion therebetween, to provide a good connection condition, and to easily achieve even a complicated wiring structure, in the case of connecting between a busbar and a pre-welded member (a terminal, another busbar, or the like) made of a metal material different from that of the busbar. A busbar unit includes a busbar made of a first metal material, and a welded member made of a second metal material to be connected to an end portion of the busbar. A welded portion between the end portion of the busbar and the welded member is configured by pressure welding between end surfaces butted against each other.