Design, Construction, and Testing of A Large-Aperture High-Field Hts Smes Coil

This paper presents the design, construction, and test results of a high-energy-density coil for a superconducting magnetic energy storage system (SMES). The coil was designed to reach 25 T at 4 K in a 100-mm bore under a program funded by ARPA-E. The coil used over 6 km of 12-mm-wide second-generation high-temperature superconductors (HTS) provided by SuperPower. Such high fields and large aperture in a coil built with a new and still-developing conductor and magnet technology created several challenges, which included large stresses and quench protection. This paper summarizes an ambitious research program that resulted in an SMES coil reaching 12.5 T at 27 K. This is the first time that such high fields and such high energy densities have been generated at a temperature over 10 K, and it opens the door for the possible use of HTS magnets in energy storage and other applications.