Nonaqueous asymmetric hybrid electrochemical supercapacitors using a nanostructured Li4Ti5O12 anode and an activated carbon cathode were built. Thin prismatic prototypes were made in the same technology as plastic Li-ion batteries. The 500F devices had a usable packaged specific energy of 11Wh/kg, with a specific power of 800W/kg at 95% efficiency, and a matched impedance power of 4000W/kg. The cycle-life ranged between 10,000 and 100,000 cycles depending on cycling conditions. The appropriateness for automotive applications was evidenced by the study of several typical examples.