 The Voltec drivetrain was initially demonstrated as E-Flex in the 2007 Chevrolet Volt concept vehicle that appeared in the North American International Auto Show which introduced the E-Flex drive system as an attempt to standardize many components of possible future electrically propelled vehicles, and to allow multiple interchangeable electricity-generating systems.The initial design as envisioned in the Volt combines an electric motor and lithium-ion battery plug-in system with a small engine (1.4 liter) powered by gasoline linked to a generator.The initial production Volt was propelled by an electric motor with a peak output of .