In order for solar+battery tech to become a viable solution, there needs to be ways to move the electricity generated by the solar panels to batteries you want to use. I.e. co-locate the two (e.g. panels & cars at home; panels & cars at work) or network them together (e.g. panels at home, cars at work.) The first scenario isn't very likely considering the sun generally shines when people are at work and the concentration of vehicles at work will overshadow the electricity generated by panels at an office building. The second scenario begs the question "who maintains the grid." In the US, this is the power companies, who could presumably adjust their business models and charge network access fees instead of production fees.