Except no cars do that. That's called a serial hybrid, which never shipped, unless you count oddballs like the BMW i3, with the optional "range extender".
I read a review of a prototype BMW mini. The turbine (fixed RPM) + batteries seemed like a great combination. Plenty of HP for highway cruising, plenty of battery+AWD for great acceleration. Turbines are efficient, crazy small for the HP, and have few moving parts. The downsize is having a fixed RPM, which would normally make them unacceptable for a car.
