It's an interesting problem, though honestly I say that battery power would not be as important if we would stop fearmongering and continue development and research in nuclear reactor research - with breeders and more efficient reactors, I'm sure we could get another 100 years of research while knowing we're not fucking our planet over, minimum.
In my opinion, battery power is one of the roughest, slowest way to achieve what they want to achieve. For long-term solutions, what we should research is materials (to be able to construct more resilient wind farms that use the more readily available higher-atmosphere winds, or even some day a space elevator that will allow more direct usage of sunlight), transmission (so that losses are minimal - also, if possible, long-range wireless transmission, with electric fields or laser, so that we may have solar power plants in space beaming down the energy if that's even possible) and space technologies (to get more resources from adjoining solar bodies, like the asteroid belt and the moon).
Of course, everything that's strictly energy-related is moot if we somehow manage to get the key to reliable, energy-positive fusion. God knows hydrogen is abundant here, and by the time it will be a problem we'll either have a BIG problem or one/two solutions: viable space travel to obtain materials/energy from space, or the technology to fuse further the byproducts, possibly down to iron, while staying energy-positive.
Still, this whole energy shebang is not something I'm looking forward too, it could easily be the end of our civilizations if we don't figure it out.