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U.S. Department of Energy
Office of Scientific and Technical Information

Flywheel-battery hybrid power system: a concept to improve electric vehicle performance

Conference ·
OSTI ID:7278982

A concept for powering the automobile was re-examined: a hybrid propulsion system design based upon demonstrated technology that could substantially improve performance, range, and consumer acceptability of a battery-powered electric vehicle. In the proposed power system, a high-energy composite flywheel is coupled to a simple, efficient, electro-mechanical transmission. Today's ''state-of-the art'' lead-acid as well as near-term and advanced battery types are examined as prime power sources. Interactive control of battery and/or flywheel drive power is provided by a versatile microprocessor-based power control unit. In the power system proposed, the flywheel augments the battery during periods of high power demand: starting, acceleration, and hill climbing. The battery supplies cruise-and-control power plus the energy required to replenish flywheel losses. With battery power demand stabilized at a low value, specific energy is maintained near maximum resulting in increased vehicle range. Vehicle kinetic energy is restored to the flywheel when traveling downhill or during any period of deceleration. The flywheel-battery hybrid is thus able to make efficient use of a regenerative braking system to recover energy. A one and a half times greater range, when compared to all-battery power, is predicted for the hybrid-powered vehicle when operated in a stop-and-go commuter environment. Acceleration rates approaching those of internal combustion powered vehicles are attainable with the hybrid power system.

Research Organization:
California Univ., Livermore (USA). Lawrence Livermore Lab.
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
7278982
Report Number(s):
UCRL-79154; CONF-770430-20
Country of Publication:
United States
Language:
English