Batteries as storage to normalize alternative (volatile) energy sources is one thing (and a big thing at that), but batteries for EVs is already last decade's thinking. They're too heavy, too expensive, take up too much room, and are too environmentally unfriendly in the production stage to have any part in EV's long term future. Even with increased efficiency and decreased costs, that will be the case for a very long time to come. Yes, they'll be the mainstay for the next few years, but EVs are already coming out that bypass the need for batteries and have considerably more range than a charged up battery.
A commercial fuel cell car, running on hydrogen, is available right now, though it has issues of easy access to hydrogen for refueling (
http://www.hyundai.com.au/why-hyundai/design-and-innovation/fuel-cell). The alternative solutions that are "close" to commercializing include direct electricity production from electrolytes (see last w-e's Weekend Australian magazine), Queensland University of Technology in Australia and Rice University's supercapacitor driven car (
http://www.takepart.com/article/2014/11/11/your-next-electric-car-may-not-even-need-battery), and Toyohashi University of Technology and Taisei Corp's car that runs off an electrified road(!) (
https://www.rt.com/news/336116-japanese-electric-car-vehicle/).
The point is that there are huge R&D efforts around the world to rid the EV's need for batteries. Some of what is being developed for EVs will spill over into stationary power requirements.
