Litz Wire Terminal Compression and Soldering Method
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Solution Overview
Problem
Conventional terminal connecting methods for litz wires with a large number of strands, such as those used in non-contact power feeding for electric vehicles, face issues with connection reliability, vibration proofness, and external appearance degradation due to excessive solder infiltration and thermal challenges.
Innovation Solution
A method involving partial insulation film removal, compression with specific forces to deform the terminal metal fitting, and subsequent soldering to securely attach the litz wire, preventing solder infiltration and maintaining flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldering is used to connect litz wire to terminal metal fitting, then electrical connection reliability is improved, but solder infiltrates into litz wire causing loss of flexibility and degraded external appearance
Solution Approach 1:
The litz wire is preliminarily compressed and temporarily fixed to the terminal metal fitting before soldering. This preliminary mechanical fixation prevents solder from infiltrating into the litz wire during the soldering process, thereby maintaining flexibility while ensuring electrical connection reliability.
Solution Approach 2:
The connection process is divided into distinct stages: preliminary compression/fixation stage and soldering stage. The preliminary fixation creates a barrier that segments the litz wire from solder infiltration, allowing soldering to proceed without compromising wire flexibility.
2Manufacturing precision
If heating temperature is increased to remove insulation films in center part of litz wire, then insulation film removal is improved, but conducting body may be melted
Solution Approach 1:
Insulation films are preliminarily removed by mechanical or chemical methods before the soldering process. This preliminary removal eliminates the need for excessive heating during soldering, preventing conducting body melting while ensuring complete insulation film removal for reliable electrical connection.
3Ease of manufacture
If litz wire is temporarily fixed by compression before soldering, then insertion is facilitated, but connection reliability may be insufficient without additional fixation
Solution Approach 1:
The temporary compression fixation and final soldering fixation are merged into a sequential process. The preliminary compression facilitates insertion and positioning, while the subsequent soldering provides permanent, reliable electrical connection, combining the benefits of both mechanical and metallurgical fixation.
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 method enhances connection reliability, vibration proofness, and maintains a clean external appearance by preventing solder intrusion and ensuring strong, flexible connections.
Implementation Method 1
compressing a first portion of the pressure fixing part with a first compression force to cause plastic deformation of an entirety of the pressure fixing part, and to temporarily fix the terminal part of the litz wire to the pressure fixing part; compressing a second portion of the pressure fixing part with a second compression force greater than the first compression force to locally cause plastic deformation of the pressure fixing part and the litz wire
Implementation Method 2
pouring molten solder from a front end side of the pressure fixing part to firmly fix the litz wire to the terminal metal fitting
Data Source
AI summary
A terminal connecting method including: removing a insulation film by a predetermined length from one end of a litz wire; inserting to a pressure fixing part a terminal part of the litz wire; compressing a first portion of the pressure fixing part with a first compression force to cause plastic deformation of an entirety of the pressure fixing part, and to temporarily fix the terminal part of the litz wire to the pressure fixing part; compressing a second portion of the pressure fixing part with a second compression force greater than the first compression force to locally cause plastic deformation of the pressure fixing part and the litz wire, the second portion being a part of the first portion; and pouring molten solder from a front end side of the pressure fixing part to firmly fix the litz wire to the terminal metal fitting.