Demountable HTS Solder Joints for Low-Resistance Current Paths

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Solution Overview

Problem

Existing technologies face challenges in creating low-resistance, high current capacity, demountable solder joint connections between superconductors, particularly for high temperature superconductors (HTS) that require significant cooling and have critical temperatures above 30° K.

Innovation Solution

The development of systems and techniques for creating demountable solder joint connections using arrays of non-insulated HTS conductors, where HTS is disposed in channels of plates and solder connections are made between conductors, allowing for low-resistance and high current capacity connections that can be easily disassembled.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional soldering methods are used to join superconducting current paths, then electrical connection is achieved, but the joints cannot be disassembled and may disrupt superconducting current paths

Engineering Contradiction:

Improvemaintaining superconducting current pathsVSAvoiddemountability of joints

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The joint is divided into two distinct parts: a soldered portion that provides electrical connection and a mechanical portion (threaded holes and fasteners) that provides demountability. This segmentation allows the electrical and mechanical functions to be separated, enabling the joint to be both reliable for superconducting current and easily disassembled when needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the joint have different properties: the soldered areas provide low-resistance electrical connection for superconducting current, while the threaded holes and fastener regions provide mechanical attachment and demountability. This local differentiation of properties allows the joint to satisfy both superconducting requirements and ease of assembly/disassembly.

Inventive Principle:

Principle #3Local quality

2Reliability

If solder connections are made between HTS conductors, then low-resistance connections are achieved, but the connections must withstand significant cooling temperatures

Engineering Contradiction:

Improvelow-resistance connectionVSAvoidcritical temperature above 30° K

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The joint uses composite construction combining HTS conductors with conventional solder materials and structural materials. The HTS conductors maintain superconductivity at operating temperatures, while the solder and structural materials provide mechanical support and electrical connection. This composite approach allows the joint to function reliably across the temperature range from critical temperature down to liquid helium temperatures.

Inventive Principle:

Principle #40Composite materials

3Power

If multiple solder joints are created in arrays, then high current capacity is achieved, but manufacturing complexity increases

Engineering Contradiction:

Improvehigh current capacityVSAvoidmanufacturing of array joints

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The HTS conductors are pre-formed with channels and the plates are pre-drilled with threaded holes before assembly. This preliminary preparation allows the actual soldering and fastening operations to be simplified during final assembly, reducing manufacturing complexity despite the large number of joints required for high current capacity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Multiple functions are merged into single components: the plates serve both as structural support and as carriers for the HTS conductors; the fasteners provide both mechanical attachment and thermal conduction paths; the solder joints provide both electrical connection and mechanical bonding. This merging reduces the total number of separate manufacturing steps despite the complexity of creating multiple joints.

Inventive Principle:

Principle #5Merging (Combining)

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 solution enables the creation of low-resistance, high current capacity connections between superconductors that can be demountably joined, facilitating the assembly and disassembly of superconducting systems without disrupting the superconducting current paths, thus maintaining efficiency and reducing thermal losses.

Implementation Method 1

a layer of solder contacting a portion of the first electrically conductive layer of the first plate and a portion of the second electrically conductive layer of the second plate

Methodology Applied

Scientific EffectSoldering: Soldering

Implementation Method 2

Superconductors are materials that have no electrical resistance to current (are 'superconducting') below some critical temperature. For many superconductors, the critical temperature is below 30° K

Methodology Applied

Scientific EffectSuperconductivity: Superconductivity

Data Source

PatentUS12243682B2Demountable solder joints for coupling superconducting current paths

Publication Date: 2025.03.04 MASSACHUSETTS INST OF TECH

AI summary

Described are concepts directed toward systems, structures and techniques to create low-resistance, high current capacity, demountable solder joint connections. Such systems, structures and techniques may be used to simultaneously create low-resistance, high current capacity, demountable solder joint connections at multiple locations between no insulation (NI) superconductors and in particular between NI high temperature superconductors (HTS) such as may be used in NI-HTS magnets.