A very low emission hybrid electric vehicle incorporating an integrated
propulsion system which includes a fuel cell, a metal hydride hydrogen
storage unit, an electric motor, high specific power, high energy density
nickel-metal hydride (NiMH) batteries, and preferably a regenerative
braking system. The nickel-metal hydride battery module preferably has a
peak power density in relation to energy density as defined by:
P>1,375-15E, where P is greater than 600 Watts/kilogram, where P is
the peak power density as measured in Watts/kilogram and E is the energy
density as measured in Watt-hours/kilogram.