There is general agreement that the 18650 battery used in the Roadster and Model S is old technology, but it continues to be used because improvements in capacity have kept it viable. It appears that the Roadster used a 2200mAh version of the 18650 cell and the Model S uses a battery with 3100mAh capacity. Given that 5300mAh versions of the 18650 battery are reportedly on the market, we could have an EPA range of 450 miles in a Model S without any change in the overall size of the battery pack. I fully recognize that the 5300mAh capacity is apt to be marketing hype and am aware that the Chinese have often overrated the capacity of their batteries, but I gotta think that Tesla is going to pour a lot of research into this old technology as they begin to build the gigafactory. Teslas with greater range are coming.