Rectangular HTS Cable Subassembly for High-Field Magnets
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Solution Overview
Problem
High-temperature superconducting power transmission cables, particularly REBCO and Bi-2223, are limited by their anisotropy and geometry, restricting their current-carrying capacity and uniformity when used in solenoidal magnet configurations, preventing effective use in high-field magnets.
Innovation Solution
A high-temperature superconducting cable subassembly with a rectangular cross-section is formed by stacking HTS tapes in parallel and wrapping them with a non-superconducting material, allowing for higher current density and flexibility in magnet applications by avoiding twisting and using no-insulation configurations to enhance current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If HTS tapes are twisted along the cable length to form power transmission cables, then the cable can be formed with available HTS tapes, but the current-carrying capacity is limited due to exposure of the tape wide surface to high magnetic fields perpendicular to the surface
Solution Approach 1:
Instead of twisting the tapes along the cable length (conventional approach), the patent inverts the approach by stacking multiple HTS tapes in parallel with their wide surfaces oriented perpendicular to the magnetic field direction. This allows the magnetic field to pass through the thin tape thickness rather than across the wide surface, thereby maintaining high current-carrying capacity while achieving the desired cable flexibility and geometry.
Solution Approach 2:
The patent transitions from a single twisted tape configuration to a multi-dimensional stacked arrangement of multiple thin tapes. By stacking tapes in parallel layers with their wide surfaces oriented perpendicular to the magnetic field, the solution exploits the third dimension (tape thickness) to minimize the exposed surface area to magnetic flux, thereby resolving the contradiction between manufacturability and current-carrying capacity.
2Adaptability or versatility
If standard cable formations are used with HTS power transmission cables, then the cables are readily available, but they cannot be used to wind magnets generating above 1 T due to anisotropy
Solution Approach 1:
The patent applies local quality by orienting each HTS tape within the stack such that its wide surface is perpendicular to the magnetic field direction. This local orientation optimization ensures that each tape experiences minimal impact from magnetic field anisotropy, allowing the overall cable structure to achieve high critical current density in high-field magnet applications where conventional cables fail.
3Ease of operation
If HTS power transmission cables are used in solenoidal magnet configurations, then magnets can be formed, but the current density is not uniform and the current-carrying capacity is inherently limited
Solution Approach 1:
The patent segments the cable structure into multiple independent HTS tape stacks arranged in parallel. Each stack can be independently optimized and positioned to ensure uniform current density distribution throughout the solenoidal magnet winding. This segmentation allows for precise control of current paths and eliminates the inherent limitations of single-twisted-tape configurations.
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 enables higher critical currents and improved current density, enabling the use of these cables in high-field magnets with reduced resistance to bending and increased efficiency compared to traditional twisted tape configurations.
Implementation Method 1
a stack of high-temperature superconducting (HTS) tapes formed of a superconducting material
Data Source
AI summary
High-temperature superconducting (HTS) devices and methods are disclosed. An HTS cable subassembly has a rectangular shaped cross section. The subassembly includes a stack of tapes formed of a superconducting material, and a cable subassembly wrapper wrapped around the stack of tapes. The tapes in the stack are slidably arranged in a parallel fashion. A cable assembly is formed of a cable assembly wrapper formed of a second non-superconducting material disposed around an n×m array of cable subassemblies. A compound cable assembly is formed by joining two or more cable assemblies. A high temperature superconducting magnet is formed of a solenoidal magnet formed of a cable subassembly, a cable assembly, and/or a compound cable assembly.