Tin-Plated Crimp Terminal for Aluminum Wire Adhesion
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Solution Overview
Problem
Conventional methods for crimping terminals to aluminum electric wires fail to achieve sufficient connecting performance due to the inferior mechanical strength and conductivity of aluminum compared to copper, and the presence of an oxide coating that hinders effective electrical continuity.
Innovation Solution
A crimping method using a copper or copper alloy terminal with a tin plating thickness of 2.1 µm to 5.0 µm on the inner surface of the conductor crimping portion, which forms a U-shaped section with inward-bent crimping pieces to securely embrace the aluminum wire, promoting adhesion and reducing contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminal is plated with tin to improve connecting performance, then the adhesion between terminal and aluminum wire is improved, but the plating thickness must be precisely controlled to avoid excessive wear or insufficient connection
Solution Approach 1:
The invention specifies a precise plating thickness range of 2.1 µm to 5.0 µm for the tin coating on the terminal's conductor crimping portion. This parameter optimization ensures sufficient adhesion between the tin plating and aluminum wire conductor while preventing excessive plating that would cause crimping die wear, thereby resolving the contradiction between connection reliability and manufacturing precision
Solution Approach 2:
The invention applies tin plating selectively to specific regions of the terminal: the conductor crimping portion (inner surface) receives a thickness of 2.1 µm to 5.0 µm, while other portions may have different plating thicknesses or no plating. This localized quality approach optimizes connection performance at the critical interface without unnecessarily increasing manufacturing complexity across the entire terminal
2Weight of moving object
If aluminum electric wire is used to reduce vehicle weight, then fuel economy and recycling capability are improved, but the inferior mechanical strength and conductivity compared to copper reduce connecting performance
Solution Approach 1:
The invention introduces tin plating as an intermediary material between the copper terminal base and the aluminum wire conductor. This intermediate layer facilitates adhesion between the dissimilar metals, overcoming the poor natural bonding between copper and aluminum, thereby maintaining high connecting performance while enabling the use of lighter aluminum wiring
Solution Approach 2:
The invention creates a composite structure consisting of the terminal base material (copper or copper alloy) combined with a tin plating layer (2.1 µm to 5.0 µm thickness). This composite construction leverages the high conductivity of copper while adding the adhesion benefits of tin, enabling reliable connection to aluminum conductors
3Reliability
If the oxide coating on aluminum conductor is broken to achieve electrical continuity, then electrical conductivity is improved, but the mechanical strength and durability of the connection are reduced
Solution Approach 1:
The invention applies tin plating to the terminal's conductor crimping portion before the crimping operation. This preliminary plating creates a protective and adhesive layer that will contact the aluminum conductor during crimping, allowing the oxide coating to be broken for electrical continuity while the tin layer maintains connection strength and prevents direct exposure of the aluminum to degradation
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 method enhances the adhesion and reliability of the electrical connection by filling gaps between wire strands and creating a gastight construction, improving both mechanical strength and electrical conductivity.
Implementation Method 1
the adhesion between the tin with which the base material of a terminal is plated and a conductor of an aluminum electric wire is increased
Implementation Method 2
since a new surface of the tin with which the base material of a terminal is plated is caused to adhere to the conductor of an aluminum electric wire by virtue of plastic deformation at the time of crimping
Data Source
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AI summary
In order to promote the adhesion of a crimp terminal (10) to an aluminum electric wire (100) by virtue of crimping to thereby realize an improvement in electric connecting performance, the thickness of tin plating applied to an inner surface of a conductor crimping portion (13) of the crimp terminal (10) is set to be in the range from 2.1 µm to 5.0 µm, and then, the conductor crimping portion (13) is crimped to a conductor (100a) of the aluminum electric wire (100).