Flywheel energy storage retrofit system for hybrid and electric vehicles

A flywheel battery, composed from commercially available low-cost materials, can be designed as an additional energy storage system for further increasing the energy efficiency of vehicles, driven mainly in cities with frequent speed changes. Increasing demands from European Union on additional reduction of CO₂ emissions in near future will offer better conditions for commercially successful serial production of hybrid and electric vehicles. Sufficient short-term power for the acceleration of a passenger vehicle in the city as well as efficient accumulation of vehicle kinetic energy during braking for several minutes can be reached even from a flywheel battery of energy capacity of about 200Wh. In combination with traction motor/generator of around 20kW and voltage 48V, the flywheel battery represents an interesting additional retrofit for conventional drives with combustion engines with positive influence on reduction of fuel consumption and therefore, also CO₂ emissions. Such solution contributes to energy smart management in frame of smart city systems.