B201 Towards a drastic enhancement of operating current density of superconducting coil systems : Effect of ultra-thin polyimide coating insulation

Abstract

REBCO superconductors are promising for coil applications such as MRI, NMR and Superconducting Energy Storage System One apparent shortcoming of REBCO conductor coils is an extremely low fraction of conductor in the coil winding, as the REBCO conductor is as thin as 100-150 μm, comparable to the insulation thickness. If we wish to achieve high overall current densities for REBCO coils, the insulation thickness on REBCO conductor must be substantially reduced. Therefore, we have developed a 4 μm ultra-thin polyimide insulation coating by electro-deposition, which is 10 fold-thinner than conventional insulations on REBCO conductors. The fraction of REBCO conductor in the coil winding manufactured by this novel conductor becomes as high as 90%. A coil design demonstrates that if we use the REBCO conductors with 4 μm-thick polyimide coating instead of the conventional insulated conductors, we can decrease the amount of conductors by -80%.