Copper-Aluminum Fusing Busbar Structure for Lower Weight and Cost

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Solution Overview

Problem

Conventional fusing busbars used in electric vehicles are heavy and expensive due to their copper composition, which increases manufacturing costs and hinders the development of lightweight vehicles.

Innovation Solution

A method involving press-welding a first conductor, typically aluminum, with second conductors, usually copper, to form a fusing busbar, where the aluminum is exposed in the middle as a melting portion and the copper is used at the ends to reduce weight and cost while maintaining electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper is used as the main material for the fusing busbar, then electrical conductivity is improved, but weight and manufacturing cost increase

Engineering Contradiction:
Improveelectrical conductivityVSAvoidweight of fusing busbar
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality by using different materials for different parts of the busbar: copper is used at the terminal ends where high electrical conductivity is critical for connection, while aluminum is used for the main body where weight reduction is prioritized. This localized material distribution optimizes both conductivity and weight characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining copper and aluminum in a single busbar structure. The copper-aluminum composite construction allows the busbar to leverage the high conductivity of copper at critical connection points while utilizing the lightweight properties of aluminum for the majority of the structure, thereby resolving the contradiction between conductivity and weight.

Inventive Principle:
Principle #40Composite materials

2Reliability

If copper is used as the main material for the fusing busbar, then electrical conductivity is improved, but manufacturing cost increases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by using different materials for different parts of the busbar: copper is used at the terminal ends where high electrical conductivity is critical for connection, while aluminum is used for the main body where weight reduction is prioritized. This localized material distribution optimizes both conductivity and weight characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining copper and aluminum in a single busbar structure. The copper-aluminum composite construction allows the busbar to leverage the high conductivity of copper at critical connection points while utilizing the lightweight properties of aluminum for the majority of the structure, thereby resolving the contradiction between conductivity and weight.

Inventive Principle:
Principle #40Composite materials

3Reliability

If a thin melting portion is created in the center of the busbar, then fusing function is provided, but structural strength is reduced

Engineering Contradiction:
Improvefusing functionVSAvoidstructural strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a thin melting portion in the center of the busbar made of aluminum, while the terminal ends are reinforced with copper. This localized variation in thickness and material composition enables the busbar to fulfill its fusing function (melting under overcurrent) in the center while maintaining sufficient structural strength at the connection points through the copper reinforcement.

Inventive Principle:
Principle #3Local quality

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 reduces manufacturing costs and weight of fusing busbars by using aluminum and copper in a structured configuration, enhancing electrical conductivity and providing a cost-effective solution for electric vehicles.

Implementation Method 1

a rolling mill to press-weld the second conductors onto the upper and lower surfaces of the first conductor

Methodology Applied
Scientific EffectPress-welding: Welding

Data Source

PatentEP4216253B1Method for manufacturing fusing busbar
Publication Date: 2026.03.11 A F W
  • EP4216253B1 patent drawingFigure 1
  • EP4216253B1 patent drawingFigure 2
  • EP4216253B1 patent drawingFigure 3

AI summary

A method for manufacturing a fusing busbar comprises a first disposing step of disposing wound second conductors 200 on upper and lower surfaces of two opposite ends of a wound first conductor 100 formed of a different material from the second conductors, a first rolling step of unwinding the first conductor and the second conductors and continuously feeding the first conductor 100 and the second conductors 200 to a rolling mill to continuously press-weld the second conductors onto the upper and lower surfaces of the two opposite ends of the first conductor 100, with a predetermined gap between the second conductors 200, and a first forming step of inserting a joined plate of the first conductor 100 and the second conductors 200 into a forming machine to press-form the joined plate into a busbar shape in which the second conductors 200 are disposed on two opposite sides of the joined plate, and the first conductor 100 is exposed in a middle of the joined plate.