Cryogenic Fuel Cooled SMES for Hybrid Vehicle Application

A novel energy storage system based on a SMES cooled by cryogenic fuel has being developed at the Dept. of Electrical Engineering of the University of Bologna. The system (which was patented by the authors) represents an alternative solution with respect to nowadays battery packs for the storage of electrical energy with large specific power. The device may find suitable application on board of road vehicles fed by liquid hydrogen with hybrid power-train (internal combustion engine and electric motor-generation), where a cryogenic tank is already present and no additional cryogenic costs are needed. The housing of the SMES inside the tank used for fuel storage, allows the exploitation of the thermal power required for the continuous evaporation of the fuel for the engine feeding to remove the AC losses from the magnet, thus avoiding the need of external supplied cooling power. In this paper both the design of the magnet and its operation in combination with electronic converter and electric motor during charge/discharge cycles are discussed. Moreover the ongoing activity for the development of a laboratory-scale prototype based on MgB2 superconductor is briefly presented.