Romanian designers want a detachable engine
One problem with today's all electric cars like the Nissan Leaf is that their range is limited. For the foreseeable future, this isn't likely to change drastically, with most experts expecting a 6 to 8 percent per year increase in battery efficiency.
On the other hand, range extended hybrids like the Chevy Volt are often not utilizing their gasoline engine for many daily trips, such as commuting to the office or grocery store. So the engine and fuel tank are dead weight in the car, lowering its overall efficiency.
The solution? Why not make the engine compartment modular?
That's the idea behind the SCI hyMod (hybrid, Modular) concept from Romanian designers Dan Scarlat, Marian Cilibeanu, and Cristian Ionescu of SCI.
The car is built with a modular engine compartment that can be easily removed and replaced, making for a lot of cool options. Imagine a rear-engine vehicle like the VW Bug that you've backed up to a swapping station, perhaps in the back of your own garage. The automated system detaches your engine and then replaces it with your choice of options (range-extending battery, a fuel cell unit and hydrogen tank, or an empty storage compartment for extra luggage carrying).
Your electric car could have enough batteries on board to take it roughly the distance most people require every day (let's say 40 miles as in the Volt). This would mean an EV with minimal weight that could be usable daily as-is. For a longer trip, you attach a range-extender. For example, to go to the concert this weekend, you'll need another 80 miles of range to get there and back easily, so you opt to put on another battery pack to more than double your current range. Going to grandma's Sunday? Add on the range-extending internal combustion engine and its small fuel tank for much longer range options.
As you can see, there are a lot of interesting and useful possibilities with this design. The hyMod may never be built, but the concept is great. It's a natural extension of the range-extending trailer idea that's also floated around as an option - trailers with combustion engines in them to act as generators for longer trips.
Here's a short video outlining how the SCI hyMod concept would work: