Quality control, general standardization and ease of access would need to be solved, but if done right this could be automated by pulling up to a vending machine and maybe eventually (super futuristic) on the fly like the way they can do in-flight fueling for aircraft.
The initial overhead could be worth it to not sit around charging, but I could also see other interests winning out here (bored people spend money, standardization isn't necessarily win-win, enabling third party service is less profitable for the car makers, &c).