Advancements in Composite Material Flywheels

Abstract

AiResearch began work on the composite flywheel in 1974 with a rotor that featured a multiring, E-glass rim and a star-shaped hub. This design overcame the two major development problems-attachment of the composite rim to the hub, and delamination of the composite material itself. Better materials and improved designs have since produced units that run at a peripheral speed of 856 m/s. An equally important consequence of these improvements is that, for the first time, composite flywheels have been tested under functional operating conditions. These tests also proved the safety advantage of composite flywheels when destructively tested in actual vehicle housings. Current programs include fabrication of a composite flywheel rotor with an energy density of 80 w-hr/kg and test of a flywheel power unit optimized for vehicle applications.