Aluminum Cable Terminal Welding Structure for Strength-Conductivity Balance

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Solution Overview

Problem

Existing connection structures of aluminum cables and terminals struggle to balance electric conduction performance, overcurrent capability, and mechanical strength, particularly due to the low strength and oxidizable nature of aluminum materials when ultrasonic welding is used.

Innovation Solution

A connection structure is developed with a specific welding area ratio (5*M≤S≤6*M) and length (5*M/W≤L≤6*M/W) for the cable welding portion, along with a wave surface design and controlled thickness, ensuring reliable bonding and mechanical integrity, and an insulating sleeve with crimping wings for enhanced stress distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ultrasonic welding is used to connect aluminum cable and terminal, then the connection strength is improved, but the balance among electric conduction performance, overcurrent capability, and mechanical strength deteriorates

Engineering Contradiction:
Improveconnection strengthVSAvoidbalance among electric conduction performance, overcurrent capability, and mechanical strength
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the welding area S to be within 4.0-6.0 times the nominal cross-sectional area M of the cable core, and controlling the cable welding portion length L to be within 5.0-6.0 times M/W (where W is the width). These specific parameter ranges optimize the balance between electric conduction performance, overcurrent capability, and mechanical strength, resolving the contradiction by finding the optimal parameter window that satisfies all three requirements simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the welding area is increased to improve mechanical strength, then the connection reliability is improved, but the electric conduction performance deteriorates

Engineering Contradiction:
Improvemechanical strengthVSAvoidelectric conduction performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent establishes an optimal parameter range where the welding area S is controlled to be 4.0-6.0 times the nominal cross-sectional area M. This specific range prevents excessive welding area that would harm electric conduction while ensuring sufficient area for mechanical strength. The lower bound (4.0M) ensures adequate mechanical bonding, while the upper bound (6.0M) prevents excessive heat input and material displacement that would reduce electric conduction performance.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the cable welding portion length is increased to improve overcurrent capability, then the current carrying capacity is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improveovercurrent capabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent controls the cable welding portion length L within a specific range of 5.0-6.0 times M/W (where M is the nominal cross-sectional area and W is the width). This parameter control ensures sufficient welding area for overcurrent capability while avoiding excessive length that would complicate manufacturing and assembly. The standardized ratio provides a simple manufacturing guideline that balances performance requirements with production efficiency.

Inventive Principle:
Principle #35Parameter changes

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 configuration achieves balanced electric conduction, strong overcurrent capability, and high mechanical strength while controlling welding process costs and complexity, ensuring reliable performance and cost-effectiveness.

Implementation Method 1

when a high-voltage wiring harness is connected with a copper terminal through an aluminum cable by ultrasonic welding

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP4068522B1Structure for connecting aluminum cable and terminal, and vehicle having same
Publication Date: 2024.05.22 BYD CO LTD
  • EP4068522B1 patent drawingFigure 1~2
  • EP4068522B1 patent drawingFigure 3~5

AI summary

A connection structure of an aluminum cable and a terminal is provided. The connection structure of an aluminum cable and a terminal includes: an aluminum cable (10), including a cable core (11), where the cable core (11) is constructed with a cable welding portion (12); and a terminal (20), welded to the cable welding portion (12), where a nominal cross-sectional area of the cable core (11) is M, and a welding area S between the cable welding portion (12) and the terminal (20) meets 5∗M≤S≤6∗M.