Superconducting Wire Rod Joint Structure for Oxygen-Annealed Connections

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Solution Overview

Problem

Existing methods for connecting superconducting wire rods often result in low critical current density and connection strength due to inadequate oxygen annealing, as the metal base materials hinder oxygen permeability, leading to insufficient oxygen reaching the connection areas.

Innovation Solution

A connection method involving a layered structure with an intermediate layer and stabilizing layer, where the base materials are joined by welding, and a connection wire rod with a superconducting conductor layer is used to bridge the superconducting conductor layers, allowing for efficient oxygen annealing and forming a connection superconducting film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the superconducting conductor layers are connected by heating in a sealed container with fine powder ejection, then the connection strength is improved, but the superconducting critical current density becomes small due to large thickness of heated portion and large contact area requirements

Engineering Contradiction:
Improveconnection strengthVSAvoidsuperconducting critical current density
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A connection wire rod is introduced as an intermediary component between the first and second superconducting wire rods. The connection wire rod includes a base material, intermediate layer, and superconducting conductor layer, serving as a mediator that bridges the two wire rods while maintaining superconducting properties and enabling effective oxygen annealing at the connection interface

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connection structure implements local quality by having different layers with specific functions: the base material provides structural support, the intermediate layer facilitates oxygen permeability for annealing, and the superconducting conductor layer maintains electrical conductivity. This localized functional differentiation resolves the contradiction between connection strength and critical current density

Inventive Principle:
Principle #3Local quality

2Strength

If the metal base materials are joined by welding, then the connection strength is improved, but the oxygen permeability is hindered, preventing sufficient oxygen from reaching the connection areas for effective annealing

Engineering Contradiction:
Improveconnection strengthVSAvoidoxygen annealing effectiveness
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The connection wire rod is segmented into multiple functional layers: base material layer for mechanical strength, intermediate layer for oxygen permeability, and superconducting conductor layer for electrical conductivity. This segmentation allows each layer to fulfill its specific function without compromising the others

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection wire rod employs a composite structure with multiple materials having different properties. The base material provides mechanical strength through welding, while the intermediate layer enables oxygen diffusion for annealing, and the superconducting layer maintains electrical properties. This composite approach resolves the contradiction between strength and oxygen permeability

Inventive Principle:
Principle #40Composite materials

3Strength

If the superconducting conductor layers are closely attached and heated to melting point, then the connection strength is improved, but the manufacturing complexity increases due to precise temperature control requirements

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention changes the processing parameters by performing oxygen annealing at lower temperatures (below melting point) compared to conventional methods that require heating to melting point. The intermediate layer enables effective oxygen diffusion at these lower temperatures, simplifying the manufacturing process while maintaining connection strength

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 approach enhances the superconducting critical current density and connection strength while enabling effective oxygen annealing, maintaining a high superconducting state even under large currents.

Implementation Method 1

the base materials are joined by welding

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

the intermediate layer has a function of enabling oxygen permeability so that oxygen reaches the connection areas

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

allowing for efficient oxygen annealing and forming a connection superconducting film

Methodology Applied
Scientific EffectAnnealing: Annealing

Data Source

PatentEP3550619B1Superconducting wire rod connection structure and connection method, and superconducting wire rod
Publication Date: 2024.08.07 FURUKAWA ELECTRIC CO LTD
  • EP3550619B1 patent drawingFigure 1~2
  • EP3550619B1 patent drawingFigure 3A~3F
  • EP3550619B1 patent drawingFigure 4A~5

AI summary

A superconducting wire rod connection structure (100) comprising: first and second superconducting wire rods (10A, 10B), wherein, the first and second superconducting wire rods are formed by layering a base material (1), an intermediate layer (2), and a superconducting conductor layer (3), the base materials of the first and second superconducting wire rods are joined to each other, and the superconducting conductor layers of the first and second superconducting wire rods are connected by a connection wire rod (10C), a separating portion (6) in which connection ends of the first and second superconducting wire rods with the base materials joined to each other are separated from the connection wire rod, and a connection superconducting film (5) which connects the superconducting conductor layers of the first and second superconducting wire rods to a portion of the connection wire rod of the separating portion.