It's not a secret that the problem with electric cars is the battery. Solve that and anyone can make an electric car. But a battery breakthrough will bring new problems.
From MIT Technology Review:
Back in 2011, President Obama set the ambitious goal of having 1 million electric vehicles on US roads by 2015. Whether automakers will hit this target is the subject of much debate. But the possibility of the widespread adoption of electric vehicles raises an interesting problem.It's good they're working on this now because when some 15 year old savant develops a lightweight battery, constructed from common household materials, electric demand will explode.
It’s easy to imagine the number of electric cars increasing but it’s much harder to see the electricity generating capacity increasing the same rate at the same time. Generating capacity will eventually catch up with this extra demand. But in the meantime, how can all these cars be charged?