The Roles of Contact Resistivity and Tape Architecture on Transverse Resistance of an NI HTS Coil

This work proposes a computational approach to estimate the equivalent resistance through which current can flow transversely in a no-insulation (NI) coil wound with High-Temperature Superconducting (HTS) tape, i.e., the transverse electrical resistance. The role of the composite layers in REBCO coated conductors and of the contact surface characteristics are distinguished, as these are key factors of the general transverse resistance. These terms are computed using simplified analytical formulae from which one can assess the impact of each mechanism singularly, e.g., the tape architecture and the temperature-dependent resistivities of its layers. The approach is validated against experimental measurements carried out on a NI single-pancake coil wound with HTS tape and tested at temperatures between 10 K and 80 K and under self magnetic field. The qualitative results obtained allow us to draw preliminary conclusions about the physical mechanisms that drive the transverse resistance in the test coil, which can eventually help during the design phase of a NI winding.