Toshiba just announced that it will be producing a lithium-ion solid state millable sheet fabricated battery with high energy density starting in the 2015 timeframe.
The energy densities are about 3X the current energy density for the best li-ion batteries currently on the market with about the same cost and 1/3 the volume. So instead of a battery that costs $20,000 and delivers a range of 200KM in something like a leaf we're talking about the same size of battery by volume, the same price but a 600KM range. For those who can't do kilometers that's about a 400 mile range.
I know we've heard this before this decade with various different small companies but this is one of the big boys who are generally speaking able to deliver on promises and are nearly always late to the party. There are likely to be even better (in terms of price) technologies out there that are not ready.
My take on this is that we have now crossed the finish line technically and all that's left is the process engineering and the building of the plants.
If the ultimate costs are 2X what they currently are for vehicles then either some people are going to have to stop driving or else it will take longer to pay for a car. Either way we're now at a reasonable range since the likelihood anyone needs to drive more than 400 miles in a day is small compared to all the times you will need to drive far less than 400 miles in a day.
It's going to be an interesting decade.