Development of 50kWh-class superconducting flywheel energy storage system

We report a development of 50 kWh-class flywheel energy storage system using a new type of axial bearing which is based on powerful magnetic force generated by a superconducting coil. This axial bearing can support a large mass. So, even at low rotational speeds, the flywheel system can have larger energy storage capacity by enlarging the mass of flywheel. Thus, this system does not require special materials that are mechanically strong enough against high circumferential velocity for the flywheel. A testing device was fabricated for evaluation of basic characteristics of the bearing. After the test with this device, a pilot system was fabricated for establishment of 50 kWh-class superconducting flywheel energy storage system technology