Asymmetric Stabilizer Structure in Superconducting Wire for Thermal Stress

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Solution Overview

Problem

Superconducting wires experience deterioration in characteristics due to temperature changes, leading to potential damage from shear stress caused by thermal expansion differences between the substrate and stabilizing layers.

Innovation Solution

A superconducting wire design with a stabilizing portion having a thicker second portion than first portion, where the second portion faces the metal substrate, reduces shear stress on the oxide superconducting layer, thereby minimizing damage and maintaining superconducting characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stabilizing layer and metal tape are made of copper with higher thermal expansion coefficient, then the superconducting wire can be stabilized electrically, but shear stress damages the oxide superconducting layer during temperature changes

Engineering Contradiction:

Improveelectrical stabilityVSAvoidoxide superconducting layer integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The stabilizing portion is segmented into two portions with different thicknesses: a first portion (thinner) facing the oxide superconducting layer and a second portion (thicker) facing the metal substrate. This segmentation allows the stabilizing layer to provide electrical stability while the asymmetric thickness distribution reduces shear stress on the superconducting layer during thermal contraction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the stabilizing layer are given different local qualities through varying thickness. The first portion has smaller thickness to reduce stress transmission to the superconducting layer, while the second portion has larger thickness to maintain overall structural stability and electrical performance.

Inventive Principle:

Principle #3Local quality

2Reliability

If the superconducting wire is cooled to critical temperature for superconducting operation, then superconducting characteristics are achieved, but thermal contraction causes shear stress that deteriorates superconducting characteristics

Engineering Contradiction:

Improvesuperconducting characteristicsVSAvoidshear stress from thermal contraction

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The asymmetric thickness design of the stabilizing portion is implemented beforehand to cushion against the harmful shear stress that will occur during thermal contraction. The thinner first portion acts as a stress buffer that protects the oxide superconducting layer from damage when the wire is cooled to critical temperature.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If the stabilizing portion has uniform thickness, then manufacturing is simplified, but shear stress from thermal expansion difference damages the superconducting layer

Engineering Contradiction:

Improvestabilizing layer fabricationVSAvoidsuperconducting layer protection

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The stabilizing portion is designed with asymmetric thickness distribution rather than uniform thickness. The first portion has smaller thickness and the second portion has larger thickness, creating an asymmetric structure that reduces shear stress on the superconducting layer while remaining manufacturable through standard deposition techniques.

Inventive Principle:

Principle #4Asymmetry

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 design effectively suppresses deterioration in superconducting characteristics by reducing shear stress on the oxide superconducting layer during temperature changes, ensuring stable performance.

Implementation Method 1

a stabilizing portion formed to cover the superconductor laminate and having a thermal expansion coefficient larger than a thermal expansion coefficient of the metal substrate

Methodology Applied

Scientific EffectThermal expansion coefficient difference: Thermal Expansion

Implementation Method 2

when the superconducting wire is cooled to a critical temperature or less (approximately 90 K or less in the case of a Y-based superconducting wire), the superconducting wire contracts and deforms

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 3

a superconductor laminate including a metal substrate and an oxide superconducting layer

Methodology Applied

Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentUS20240379267A1Superconducting wire and superconducting coil

Publication Date: 2024.11.14 FUJIKURA LTD

AI summary

A superconducting wire includes: a superconductor laminate including a metal substrate and an oxide superconducting layer; and a stabilizing portion that covers the superconductor laminate and that has a thermal expansion coefficient larger than a thermal expansion coefficient of the metal substrate. The superconductor laminate has: a first main surface on which the oxide superconducting layer is disposed, and a second main surface on which the metal substrate is disposed. The stabilizing portion includes: a first portion facing the first main surface; and a second portion facing the second main surface. A thickness of the second portion is larger than a thickness of the first portion.