Interesting. Toyota has partnered with other makers in the past including, for example, GM. But with the reported plans to manufacture electric vehicles as well as like plans of other makers one has to wonder how many charging stations will be needed and how to locate them as well as what the effect will be upon the electric grid.
More EVs will actually benefit the grid. See V2G. And this becomes viable once you have enough EV's around and the range of each vehicle is long enough to only need weekly charging (like 200-300 mile range we are starting to see).
Any large additional electrical load on the gird will be problematic. Replacing the vehicular energy now provided by gasoline with generated electricity will cause a huge increase in electrical demand, and the current U.S. electric grid is not up to that task, as has been widely reported. The possibility that electric vehicles will need less frequent charging will not diminish the amount of electricity needed for recharge - it only makes the demand less individually frequent. Studies already have been done - people returning home from work, for example, tend to do so at peak electrical use demand times and to add to the situation plug in their vehicles when they return home.
That is why cars need to be plugged in at all times and charging managed. Suck in the excess during renewable high output/low consumer demand. Feed back to the grid when situation is reversed. Yes, the grid would need some upgrade too - increase capacity and increase smarts.