Ultrasonic Wire Busbar Connection via Copper Bonding Member

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Solution Overview

Problem

Existing connection structures for electric wires to busbars, particularly when the busbar is made of aluminum or copper, face challenges in stably holding the wire due to low spring properties and stress relaxation, leading to unreliable bonding and unstable holding forces.

Innovation Solution

A connection structure that includes a conductive metal bonding member with a crimping portion, which is ultrasonically bonded to both the electric wire and the busbar, ensuring stable fixation and high connection reliability by interposing the conductor between the busbar and the bonding member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the busbar is made of aluminum, then the conductor can be bonded to the busbar, but the holding position of the electric wire deviates due to low spring property

Engineering Contradiction:
Improvebonding strengthVSAvoidholding position accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A bonding member made of copper or copper alloy is introduced as an intermediary between the aluminum busbar and the copper conductor. This bonding member includes a bonding plate portion that contacts the busbar and a crimping portion that holds the electric wire, serving as a mediator that enables reliable bonding while maintaining precise holding position despite the low spring property of aluminum busbar

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the busbar is made of copper, then the conductor can be bonded to the busbar, but the holding force decreases due to stress relaxation

Engineering Contradiction:
Improvebonding strengthVSAvoidholding stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The bonding member serves as an intermediary that separates the bonding function from the holding function. The bonding plate portion provides stable bonding to the copper busbar, while the crimping portion maintains reliable holding force on the electric wire, preventing stress relaxation from affecting holding stability

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the holding position of the electric wire deviates, then the conductor cannot be smoothly bonded, but connection reliability is lowered

Engineering Contradiction:
Improvebonding processabilityVSAvoidconnection reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The bonding member with its crimping portion acts as an intermediary that secures the electric wire at the correct position before bonding. This ensures the conductor is properly positioned and can be smoothly bonded to the busbar, maintaining both manufacturing ease and connection reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The crimping portion performs preliminary action by holding and positioning the electric wire before the ultrasonic bonding process. This preliminary positioning ensures that when bonding occurs, the conductor is correctly aligned with the busbar, enabling smooth bonding and reliable connection

Inventive Principle:
Principle #10Preliminary action

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 solution provides a stable and reliable connection between the electric wire and the busbar, preventing conductor damage and ensuring uniform bonding, while also protecting the ultrasonic bonding device's contact surfaces from metal transfer or wear.

Implementation Method 1

a busbar made of a conductive metal material on which the bonding member is overlapped and ultrasonically bonded with the conductor interposed between the busbar and the bonding member

Methodology Applied
Scientific EffectUltrasonic bonding: Ultrasonic Vibration

Data Source

PatentEP3863120B1Electric wire connection structure and connection method
Publication Date: 2022.04.13 YAZAKI CORP
  • EP3863120B1 patent drawingFigure 1
  • EP3863120B1 patent drawingFigure 2
  • EP3863120B1 patent drawingFigure 3

AI summary

A connection structure for an electric wire includes an electric wire that has a conductor and an outer sheath covering the conductor; a bonding member that is made of a conductive metal material and is attached to the electric wire and; and a busbar that is made of a conductive metal material and on which the bonding member is overlapped and ultrasonically bonded with the conductor interposed between the busbar and the bonding member. The bonding member includes a crimping portion for crimping and fixing the electric wire.