Research and development of superconducting magnetic energy storage system

Bi-2212/Ag Rutherford cable is expected as a high temperature superconducting magnet for SMES use because its critical current is 3.5 kA at 0 T, 4.2 K and it has the structure of enduring large magnetic force. Tests on the relation of critical current and tensile strain of the strand were performed. It was confirmed that I c and n -value began to decrease when the tensile strain of the strand increased over 0.6%. The share of the load between the strand and the Ni-base metallic core was found by examining the strength of the strand and the cable, and evaluating them with the above data. It was considered that the critical stress of this Rutherford cable was nearly 240 MPa which was necessary to design 20 T-class magnet.