Do electric cars need a breakthrough battery technology?

The Atlantic has been running a series this week about the future of electric car batteries. Here Alexis Mardrigal has a post that summarizes the arguments for and against the need for a breakthrough technology. The punch line is we don't know if incremental changes are good enough, or on which path we might become dependent. Mardgral's post has links to all of the relevant posts form the week, most of which are well worth reading.