Fundamental Study of MgB₂ Superconducting Coil for Storage Devices

Abstract

The authors carried out a basic study on a power storage coil made of MgB₂ superconducting wires which was expected to require less cooling and lower manufacturing costs. First, for manufacturing the storage coil, the basic characteristics of MgB₂ superconducting wire were evaluated. The characteristics at 20 K under 1.5 T were a critical current of 170 A for the in-situ MgB₂ wire and 200 A for the ex-situ MgB₂ wire. Based on these results, MgB₂ conductors and prototype storage coils were produced and their performance was evaluated. The prototype was successfully energized to 600 A under 1.5 T at less than 25 K, which are the basic requirements for several 10 kJ class coils, and there was no significant deterioration through conductor and coil processing.