Flywheel, flywheel design method and flywheel storage system

摘要

The present invention provides a flywheel which has a high energy density, a designing method which facilitates designing of the flywheel, and a power storage system which can simultaneously achieve the increase of power storage energy and lightness of weight by adopting the flywheel. A flywheel A is provided with: a low-density disk 10 which has a low average density; and a high-density outer edge 11 which is provided to the outer circumference of the low-density disk 10 and which has an average density higher than that of the low-density disk 10.