Flexible Copper-Core Conductor With TIG-Welded Sheath Joints

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Solution Overview

Problem

Existing high-temperature solid oxide electrolyzers and fuel cells face significant electrical resistance and corrosion issues due to the use of conventional materials like stainless steel and copper, leading to high energy losses and rapid oxidation, especially at temperatures above 600°C.

Innovation Solution

A flexible electrical conductor is developed, comprising a copper core protected by a stainless steel sheath, with TIG welding and brazing connections, eliminating the need for hot isostatic compression and reducing oxidation risks, thereby maintaining low electrical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper conductors are used to ensure electrical conductivity, then electrical conductivity is improved, but flexibility deteriorates due to copper's inherent rigidity

Engineering Contradiction:
Improveelectrical conductivityVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The conductor is divided into multiple copper strands instead of using a single solid copper conductor. This segmentation allows the conductor to flex while maintaining electrical conductivity, as the individual strands can move independently relative to one another.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining copper strands with a polymer coating. The copper provides electrical conductivity while the polymer coating provides flexibility and protection, creating a material that exhibits properties of both components.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If soldering is used to connect conductors, then ease of manufacture is improved, but reliability deteriorates due to brittle solder joints and contamination risks

Engineering Contradiction:
Improveease of connectionVSAvoidjoint reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention replaces the chemical soldering process with a mechanical welding process (friction stir welding). This mechanical approach eliminates the need for solder materials and avoids the associated reliability issues while maintaining ease of manufacture through a straightforward welding procedure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Weight of moving object

If aluminum conductors are used to reduce weight, then weight is improved, but manufacturing precision deteriorates due to aluminum's softness and difficulty in handling

Engineering Contradiction:
Improveconductor weightVSAvoidhandling precision
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The aluminum conductors are pre-coated with a polymer layer before assembly. This preliminary coating provides a protective surface that facilitates handling and prevents deformation during manufacturing processes, thereby improving manufacturing precision while retaining the weight advantages of aluminum.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If friction stir welding is used to ensure reliable joints, then reliability is improved, but manufacturing precision deteriorates due to protrusions and embedments

Engineering Contradiction:
Improvejoint strengthVSAvoidsurface smoothness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention removes the problematic protrusions and embedments created by traditional friction stir welding through a secondary processing step. This extraction of defects restores surface smoothness and manufacturing precision while preserving the reliable joint strength achieved by the welding process.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution significantly reduces electrical losses by a factor of 10 compared to conventional materials, ensuring efficient electrical conduction and resistance to thermal cycling in oxidizing environments, while allowing for flexible connections and reduced manufacturing costs.

Implementation Method 1

The flexible electrical conductor comprises conductor elements (50) which are connected to one another by friction stir welding

Methodology Applied
Scientific EffectFriction stir welding: Friction Welding

Data Source

PatentEP4526072B1Flexible electrical conductor comprising elements joined together by tig welding, method for manufacturing such a flexible electrical conductor, use of at least one such electrical conductor, and electrochemical system comprising such a flexible electrical conductor
Publication Date: 2026.04.08 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4526072B1 patent drawingFigure 1~2
  • EP4526072B1 patent drawingFigure 3~4
  • EP4526072B1 patent drawingFigure 5~7

AI summary

The main subject matter of the invention is a flexible electrical conductor (70) comprising: an assembly (72) comprising a flexible conductive core (74) made of a first metal material and a sheath (79) covering the conductive core (74) and made of a second metal material having an electrical resistivity higher than the electrical resistivity of the first metal material; a first connection strip (78) formed at least in part by the second metal material and connected to a first end (72a) of the assembly (72), wherein, at the first end (72a) of the assembly (72), the sheath (79) and the first connection strip (78) are bonded by TIG welding, and the conductive core (74) and the first connection strip (78) are bonded by fillet-brazing or soldering.