Comment by ZeroGravitas

In the auto industry these are usually called a series hybrid and there have been a handful. The Chevy Volt (though it had the ability to directly connect the engine to the wheels at highway speeds), and the BMW i3 and i8, the Fisker Karma/Karma Revero. The new Ram Ramcharger truck and the second gen Ford Lightning will also be series hybrids.

It's a really good drivetrain that was unfortunately made untenable for a long time by a combination of regulation and market forces.