What is the planned battery range, and How far do you think you want to "extend" the range ?...20%, 100%, or unlimited range ??Looks like it then, yes.
What about the range extender, anyone has done it? What would be the easiest way to make it work on an existing system?
In most cases, its simpler, cheaper, and more efficient to simply increase the battery capacity to "extend" the range, but if you are thinking of having a range extender that can maintain performance once the battery is flat , until the fuel is empty,....then you want to be thinking of a Plug in Hybrid drive instead.
Google the BMW i3 REX.