Superconducting Wire Electrode Joining Structure

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Superconducting coils experience normal conduction transitions and potential burning due to temperature increases near electrodes, caused by heat dissipation and external heat permeation, leading to instability and failure.

Innovation Solution

The electrode unit joining structure for superconducting wires includes a buffering member to fill the gap between the wire, cover tape, and electrode, with electrical connection through solder, and a superconducting cover tape that covers the electrode, reducing contact resistance and facilitating effective cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electrode is directly connected to the superconducting wire, then electrical connection is achieved, but temperature increases near the electrode cause normal conduction transitions

Engineering Contradiction:
Improvesuperconducting state stabilityVSAvoidtemperature near electrode
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The electrode connection structure is divided into multiple segments: the electrode itself, the electroconductive layer for electrical connection, the insulating layer for electrical isolation, and the buffering member for mechanical stress absorption. This segmentation allows each component to perform its specific function while preventing temperature-induced normal conduction transitions in the superconducting wire.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The buffering member acts as an intermediary between the electrode and the superconducting wire, filling the gap and absorbing mechanical stresses. The insulating layer serves as an intermediary to prevent direct electrical contact while allowing thermal management. These intermediary components protect the superconducting wire from temperature increases caused by direct electrode connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the electrode is made larger to reduce contact resistance, then electrical connection improves, but heat dissipation increases causing temperature rise

Engineering Contradiction:
Improveelectrical connection qualityVSAvoidtemperature near electrode
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The electroconductive layer is applied locally to the electrode surface in contact with the superconducting wire, providing low contact resistance only where needed. The insulating layer is applied to other surfaces to prevent unwanted electrical contact and manage heat dissipation. This local differentiation of properties allows optimized electrical connection without excessive heat generation.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If mechanical stress is applied to the superconducting wire during coil winding, then coil formation is achieved, but the wire may transition to normal conduction state

Engineering Contradiction:
Improvecoil winding processVSAvoidsuperconducting state maintenance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The buffering member is pre-installed between the electrode and the superconducting wire to provide mechanical cushioning before coil winding begins. This beforehand cushioning protects the superconducting wire from excessive mechanical stresses during the coil formation process, preventing normal conduction transitions while allowing necessary deformation for coil winding.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The connection structure uses composite materials with different properties: the electroconductive layer for electrical conductivity, the insulating layer for electrical isolation and thermal management, and the buffering member for mechanical compliance. This composite structure allows the coil to be wound with appropriate mechanical stress while maintaining superconducting state stability.

Inventive Principle:
Principle #40Composite materials

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 configuration suppresses temperature increases near the electrodes, prevents normal conduction transitions, and enhances mechanical stability, thereby preventing burning and maintaining the superconducting state.

Implementation Method 1

the electrode, the superconducting wire, and the superconducting cover tape are electrically connected to each other

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

heat dissipation at a connection portion

Methodology Applied
Scientific EffectHeat Dissipation: Convection

Implementation Method 3

heat permeating from the outside

Methodology Applied
Scientific EffectThermal Conduction: Conduction (thermal)

Data Source

PatentEP2544198B1Electrode unit joining structure for superconducting wire material, superconducting wire material, and superconducting coil
Publication Date: 2019.04.24 FUJIKURA LTD
  • EP2544198B1 patent drawingFigure 1A~1B
  • EP2544198B1 patent drawingFigure 2
  • EP2544198B1 patent drawingFigure 3

AI summary

An electrode unit joining structure for a superconducting wire includes: a superconducting wire comprising a first base member, a first superconducting layer provided on the first base member, and a first electroconductive layer provided on the first superconducting layer; an electrode provided on the first electroconductive layer at an end portion of the superconducting wire; and a superconducting cover tape comprising a second base member, a second superconducting layer provided on the second base member, and a second electroconductive layer provided on the second superconducting layer, the superconducting cover tape being provided so as to cover at least part of the electrode, wherein the second electroconductive layer of the superconducting cover tape is disposed on the electrode side, and the electrode, the superconducting wire, and the superconducting cover tape are electrically connected to each other.