Present and Future Applications of Supercapacitors in Electric and Hybrid Vehicles

This paper is concerned with supercapacitors (electrochemical capacitors) and their applications in electric drive vehicles in place of or in combination with batteries. The electric drive vehicles considered are hybrid vehicles. Data are presented for the new carbon/carbon device from Skeleton Technologies showing an energy density of 9 Wh/kg and 95% efficient power capability of 1730 W/kg. Both of these characteristics are significantly better than those of commercially available devices. Test data are also shown for a hybrid supercapacitor from Yunasko that has an energy density greater than 30 Wh/kg and a 95% efficient power capability of 3120 W/kg. This device has the best performance of any supercapacitor device tested at UC Davis to date. Various vehicle applications of supercapacitors have been reviewed in detail. Simulation results are presented for light duty vehicles using supercapacitors in place of lithium batteries in hybrid vehicles. It was found in all cases that the vehicles using the supercapacitors had the same as or better performance than those using batteries and in general were more efficient.