Not exactly. What you are describing is correct for things like a Prius, with dual drivetrains. It is certainly not correct for cars like the Chevy Volt (or the

Not exactly. What you are describing is correct for things like a Prius, with dual drivetrains. It is certainly not correct for cars like the Chevy Volt (or the BMW i3), with the main engine being the electric one, and a gasoline generator. This combination is less complex than a normal car – for one, you can remove basically the entire transmission and hook up the eletric engine directly (with maybe a reduction gear like a Leaf). The gasoline engine can be much smaller and simpler as it is only driving a generator (and maybe not even running all the time, depending on battery and workload). Such a design is not as clean as a pure EV, but it is definitely better than what we currently have.