Copper-Alloy Weld Interface for Base-Metal Cable Terminals
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Solution Overview
Problem
Connecting conductors made of base metals to copper terminal elements is challenging due to mechanical and electrochemical issues, such as corrosion and poor electrical conductivity, which are exacerbated by the high physical stresses in automotive applications.
Innovation Solution
Applying a copper alloy or a mixture comprising copper and a base metal as an adhesive layer at the weld joint between the conductor and the terminal element, improving both mechanical and electrical connections by preventing corrosion and enhancing weld quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductor comprising a base metal is directly connected to a copper terminal element, then weight and cost are reduced, but mechanical reliability and electrical conductivity deteriorate due to corrosion
Solution Approach 1:
The patent applies a coating layer comprising copper and at least one base metal to either the conductor or terminal element before welding. This coating acts as an intermediary that prevents direct contact between dissimilar metals, thereby preventing galvanic corrosion while maintaining electrical conductivity and mechanical strength. The coating layer is specifically applied at the weld joint area to address the corrosion problem at the connection point.
Solution Approach 2:
The patent uses a composite coating material consisting of copper and base metal (such as aluminum, zinc, or tin) in specific proportions. This composite coating combines the beneficial properties of both metals: copper provides electrical conductivity and corrosion resistance, while the base metal provides weight reduction and cost benefits. The composite structure prevents galvanic corrosion by creating a barrier layer that eliminates direct electrochemical contact between dissimilar metals.
2Strength
If copper is used for terminal elements and conductors, then electrical conductivity and mechanical strength are maintained, but weight and cost increase
Solution Approach 1:
The patent applies the copper-containing coating only at the weld joint area rather than coating the entire conductor or terminal element. This local application provides corrosion protection and maintains electrical conductivity where it is most critical (at the connection point) while leaving the bulk materials as lightweight base metals, thereby reducing overall weight.
Solution Approach 2:
The patent employs a composite coating material that combines copper with base metals in a controlled manner. The coating contains copper particles or powder dispersed in a base metal matrix, creating a material that has both the electrical conductivity benefits of copper and the weight advantages of base metals. This composite structure allows the connection to maintain mechanical strength and electrical performance while the overall assembly remains lightweight.
3Reliability
If a coating layer of copper alloy is applied at the weld joint, then corrosion resistance and weld quality improve, but manufacturing complexity increases
Solution Approach 1:
The patent specifies particular ranges for the coating thickness (0.1-10 micrometers) and copper content (10-90 wt%) to optimize both corrosion resistance and weldability. By defining specific parameter ranges, the patent ensures that the coating provides adequate protection without being so thick or complex that it complicates the manufacturing process. These parameter specifications make the coating process controllable and repeatable.
Solution Approach 2:
The coating layer serves as an intermediary that simplifies the welding process by providing a consistent, controlled interface between dissimilar metals. Rather than dealing with the complexities of direct welding between aluminum and copper (which have vastly different physical and chemical properties), the coating creates a transitional layer that facilitates welding, improves joint quality, and reduces manufacturing complexity overall.
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 reliable mechanical and electrical connection that withstands high forces and reduces corrosion, ensuring the terminal assembly meets the stringent requirements of the automotive industry.
Implementation Method 1
the connection of a terminal element comprising copper to a conductor comprising a base metal is electrochemically problematic because the point of contact of copper to the base metal is at risk of corrosion
Implementation Method 2
coating, at least at the weld joint, with an adhesive layer of a copper alloy or a mixture comprising copper and at least one base metal
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
The present invention relates to a method for connecting a conductor (1) comprising a base metal to a terminal element (2)comprising copper, and to a terminal assembly(18) with a conductor (1) comprising a base metal and with a terminal element (2)which comprises copper and which is connected to the conductor (1). In order to reliably connect a conductor (1) comprising a base metal and a terminal element (2)comprising copper to one another both mechanically and in an electrically conductive manner, it is envisaged according to the invention that the conductor (1) and/or the terminal element (2)is coated, at least at the weld joint (5, 10), with a copper alloy or a mixture comprising copper and at least one base metal, before the conductor (1) and the terminal element (2)are welded onto one another. In this manner, a terminal assembly(18) can be produced which satisfies the strict requirements for use in the automotive industry and in which the conductor (1) is welded to the terminal element (2), wherein the weld seam (19) has a layer of a copper alloy or of a mixture comprising copper and at least one base metal.