Composite rotor for flywheel energy storage system

A composite rotor comprising:

• a rotor body extending along a longitudinal axis, the rotor body including:
• a first component extending longitudinally along at least a portion of the rotor body, and
• a second component extending longitudinally along at least a portion of the rotor body, at least a portion of the second component disposed concentrically around the first component;
• wherein the first component and the second component together define an internal region,
• wherein a radial thickness of the first component and a radial thickness of the second component vary along the longitudinal axis;
• and
• at least one magnet disposed on an inner surface of the second component within the internal region;
• wherein the second component further comprises an internal recess and the first component is disposed in the internal recess;
• and wherein the at least one magnet on the inner surface of the second component is longitudinally spaced from the first component in the internal recess of the second component.