TIG-Welded Copper-Core Conductor for High-Temperature Oxidation Resistance

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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, leading to high energy losses and rapid oxidation of copper conductors in oxidizing environments, which are not optimized for thermal cycling.

Innovation Solution

A rigid electrical conductor is developed comprising a copper core protected by a stainless steel sheath, welded together using TIG welding, with connecting tabs made of stainless steel, eliminating the need for hot isostatic compression and reducing ohmic losses by a factor of 10.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If copper conductors are used in high-temperature oxidizing environments, then electrical conductivity is improved, but rapid oxidation and corrosion occur

Engineering Contradiction:
Improveelectrical conductivityVSAvoidoxidation resistance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies composite materials by creating a multi-layer structure consisting of a copper core surrounded by a nickel alloy sheath. The copper core provides high electrical conductivity, while the nickel alloy sheath provides oxidation resistance in high-temperature environments. This composite structure resolves the contradiction by combining materials with complementary properties, allowing the conductor to maintain both low electrical resistance and high corrosion resistance simultaneously.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements the nesting principle by placing the copper conductor core inside the nickel alloy protective sheath. The copper core is nested within the oxidiation-resistant sheath, creating a protective enclosure that allows the copper to function at high temperatures without direct exposure to the oxidizing environment. This nested structure enables the inner material to benefit from the protective properties of the outer material.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If stainless steel materials are used for electrical conductors, then oxidation resistance is improved, but electrical resistance increases significantly

Engineering Contradiction:
Improveoxidation resistanceVSAvoidelectrical conductivity
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent resolves this contradiction by using composite materials where the copper core provides excellent electrical conductivity while the nickel alloy sheath provides oxidation resistance. This eliminates the need to use stainless steel for the entire conductor structure, allowing optimal electrical properties in the core while maintaining environmental resistance through the sheath.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by assigning different functional properties to different parts of the conductor. The copper core is optimized for electrical conduction, while the nickel alloy sheath is optimized for oxidation protection. Each material is placed where it provides the most benefit, creating a functionally optimized composite structure.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If conventional welding methods are used for assembling conductor components, then manufacturing complexity is reduced, but thermal cycling degradation occurs

Engineering Contradiction:
Improveassembly simplicityVSAvoidthermal cycling resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by modifying the welding process parameters, specifically using pulsed current welding with controlled heat input. This welding method changes the thermal parameters during assembly, reducing peak temperatures and thermal gradients that would otherwise cause degradation during thermal cycling. The controlled welding parameters ensure strong joints while minimizing thermal damage to the conductor components.

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

The solution significantly reduces electrical resistance and corrosion, allowing efficient electrical conduction in high-temperature oxidizing environments, thus enhancing the energy efficiency of solid oxide cell stacks.

Implementation Method 1

welded together using TIG welding

Methodology Applied
Scientific EffectTIG welding: Welding

Implementation Method 2

rigid electrical conductor comprising a copper core protected by a stainless steel sheath

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4526071B1Rigid electrical conductor comprising elements connected by tig welding, method for manufacturing and using such an electrical conductor, and electrochemical system comprising such an electrical conductor
Publication Date: 2026.03.25 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4526071B1 patent drawingFigure 1~2
  • EP4526071B1 patent drawingFigure 3~4
  • EP4526071B1 patent drawingFigure 5~7

AI summary

The main subject matter of the invention is a rigid electrical conductor (70) comprising: an assembly (72) comprising a rigid conductive rod (74) made of a first metal material and a sheath (76) covering the conductive rod (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 conductive rod (74), the sheath (76) and the first connection strip (78) are bonded together by TIG welding with the addition of a material made of the second metal material.