Investigation of HTS CrossConductor Joints, Connectors, and Terminations

The high-temperature superconductor (HTS) CrossConductor (HTS CroCo) is a modified stacked-tape arrangement, aiming for high current density and easy long-length fabrication. It is intended to be used as a strand for a high current cable in industrial dc applications or large high-field magnets. In order to allow for an economical operation, terminations, joints, and connector parts need to be sufficiently low-resistive to minimize the heat generation and thus the cooling cost. On the other hand, industrial applicability requires reliable and easy-to-use concepts. In this paper, three approaches to fabricate soldered joints and terminations for HTS CroCos are presented and assessed based on resistance measurements at 77 K, self-field. Termination resistances of some tens of nano-Ohms were achieved for the best termination concepts. Additionally, four types of low-resistive HTS CroCo connectors with bending radii of less than 5 cm are introduced and assessed. For the best connector types, some tens of nano-Ohms were achieved giving rise to a heat generation of less than 1 W at operating conditions.