"Hybrids are classified by the division of power between sources; both sources may operate in parallel to simultaneously provide acceleration, or they may operate in series with one source exclusively providing the acceleration and the second being used to augment the first's power reserve. The sources can also be used in both series and parallel as needed, the vehicle being primarily driven by one source but the second capable of providing direct additional acceleration if required."
"A full hybrid, sometimes also called a strong hybrid, is a vehicle that can run on just the engine, just the batteries, or a combination of both. The Toyota Prius, Toyota Camry Hybrid, Ford Escape Hybrid/Mercury Mariner Hybrid, Ford Fusion Hybrid/Mercury Milan Hybrid, Kia Optima Hybrid, as well as the General Motors 2-mode hybrid trucks and SUVs, are examples of this type of hybridization as they are able to be propelled on battery power alone. A large, high-capacity battery pack is needed for battery-only operation. These vehicles have a split power path that allows more flexibility in the drivetrain by inter-converting mechanical and electrical power, at some cost in complexity. To balance the forces from each portion, the vehicles use a differential-style linkage between the engine and motor connected to the head end of the transmission."
Hybrid vehicle drivetrain - Wikipedia, the free encyclopedia