You cannot just plug and play, Toyota's vehicles dont have the requisite chassis and space for the battery pack. They'd have to redesign their cars from the ground up, and they're too busy with hybrids and fuel cells to undertake a bev revolution.
Toyota and Panasonic announced a battery tech partnership in January. They also partnered with Mazda and licensed all their EV patents. If you follow them closely in JDM, they have lots of EV concept vehicles in play.
