2212 Multifilament Superconducting Wire with High Resistance Sleeves
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Solution Overview
Problem
Current high-temperature superconducting (HTS) wires fail to operate with low inductive loss at higher temperatures and current densities in time-varying magnetic fields, limiting their application in advanced accelerators and transformers due to insufficiently small transverse filament dimensions and elevated inter-filament resistances.
Innovation Solution
The development of a 2212 multifilament superconducting wire with high resistance sleeves around individual filaments or filament bundles, featuring axial twist and round or rectangular shape, to reduce losses by increasing inter-filament resistance and optimizing wire architecture through melt texturing and wire drawing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If HTS wires use larger transverse filament dimensions to maintain mechanical strength and ease of manufacture, then manufacturing is easier, but inductive loss increases in time-varying magnetic fields
Solution Approach 1:
The wire is divided into multiple small-diameter filaments (each less than 0.5mm, preferably 0.1-0.3mm) bundled together to form the composite conductor. This segmentation reduces the loop area for eddy currents and minimizes hysteretic losses while maintaining the overall mechanical strength through the silver matrix and strand construction
Solution Approach 2:
The invention uses a composite structure combining superconducting 2212 filaments with a silver matrix and copper-clad steel strands. The silver provides electrical stability and mechanical support, while the copper-clad steel outer layer provides tensile strength, allowing the use of small-diameter superconducting filaments without compromising overall wire strength
2Reliability
If HTS wires use lower inter-filament resistance to improve current sharing, then current distribution improves, but coupling loss increases in time-varying magnetic fields
Solution Approach 1:
The silver matrix surrounding each filament provides locally optimized electrical contact for current sharing, while the overall high inter-filament resistance is achieved through the combined effect of multiple isolated filament paths. The silver sheath thickness and purity are controlled to provide sufficient local conductivity without creating low-resistance paths between adjacent filaments that would increase coupling losses
3Temperature
If HTS wires operate at higher temperatures to reduce cooling costs, then operating temperature increases, but inductive loss increases in time-varying magnetic fields
Solution Approach 1:
The use of many small-diameter filaments segmented by high-resistance sleeves reduces the effective loop area for eddy currents. This segmentation maintains low inductive losses even at higher operating temperatures (4.2K and above) where the superconductor's critical current density decreases, allowing the system to operate at elevated temperatures without proportionally increased losses
4Loss of energy
If HTS wires use smaller transverse filament dimensions to reduce inductive loss, then inductive loss decreases, but manufacturing precision requirements increase
Solution Approach 1:
The small-diameter filaments are pre-formed and bundled into sub-elements before final strand assembly. The silver matrix is prepared in advance to accommodate the precise filament arrangement, and the drawing process is designed to maintain filament integrity and spacing throughout reduction to final dimensions, making the high-precision small filament structure manufacturable
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 enables superior current density at higher operating temperatures while achieving low loss features, making the 2212 wire suitable for high-field applications by reducing hysteretic, eddy, and coupling losses, thus enhancing the performance of HTS conductors in magnetic fields.
Implementation Method 1
applying a second heat to the round-shaped wire or the hexagonal-shaped wire to oxidize the metal precursor film, forming the 2212 multifilament superconducting wire comprising the resistance sleeves
Implementation Method 2
High temperature superconducting (HTS) oxide based wires provide the opportunity for ground breaking advances
Implementation Method 3
high resistance sleeves around individual filaments or filament bundles... to reduce losses by increasing inter-filament resistance
Implementation Method 4
reducing hysteretic, eddy, and coupling losses... in the time varying magnetic fields of advanced accelerators
Implementation Method 5
drawing down the second billet to a final diameter; twisting the round-shaped wire or the hexagonal-shaped wire about a longitudinal axis
Data Source
AI summary
Methods and devices involving 2212 multifilament superconducting wire with resistance sleeves. More specifically, methods and devices including high resistance sleeves around individual, unmerged filaments or filament bundles, with axial twist, and with round or rectangular wire shape for lower losses in and ramped fields.