Liquid hydrogen tank with cylindrical superconducting bearing for automotive application

Using the concept of superconducting suspension of the inner tank in an outer vessel, the authors have designed and constructed a prototype of a liquid-hydrogen storage tank for automotive application. In contrast to the earlier model with planar design of the bearing, they used a rotationally symmetric arrangement with the inner tank suspended over a central frame bar. The bearing consists of superconducting rings fixed to the central tube of the inner tank and a system of permanent magnets mounted on the frame bar. No additional cooling of the superconductors (YBaCuO rings prepared by a modified multi-seeding process and Bi-2212 rings prepared by the melt cast process) is required. For suspension of the tank in the warm state above Tc, they used newly developed actuators with main springs made of shape-memory alloy. When the tank is filled with liquid hydrogen, the actuators release the tank, thereby providing absolutely passive activation of the bearing.