While the nickel metal hydride (Ni-MH) battery will remain the choice for Prius, Camry and Highlander hybrids, Toyota is doing some research and development with lithium ion batteries.
The Lexus' whirligig is familiar from the Toyota Camry and Avalon hybrids: a lean-burning Atkinson-cycle, 2.5-liter in-line four-cylinder (156 hp) coupled with two electric motors, one a 141-hp traction motor, the other a starter-generator.