For battery electric vehicles to overcome the built-in advantages of vehicles rocking conventional internal combustion engines, many analysts point to battery costs as being the determining factor. But we also need to consider weight. in particular, Battery weight.
The main goal of the Tesla Gigafactory is to bring battery costs down by some 30%, allowing the Tesla Model III the ability to offer a 200-mile driving range for just $35,000. Elon Musk has again and again targeted the BMW 3-Series as the Model III’s main competitor, and with a curb weight of just over 3,400 pounds (1,542 kgs), the Bimmer represents an excellent “goal” weight for the average family sedan. The Tesla Model S, with its 4,600 pound (2,086 kgs) curb weight, is a much heavier car in comparison, with about 1,600 of those pounds dedicated to the battery alone. In order to bring the batteries weight down Tesla must bring the watt-hours per kilogram (Wh/kg) up, and it will do that with new battery cell technology.
Currently, Tesla uses thousands of individual Panasonic 18650 laptop battery cells in its battery packs, which cost an estimated $250/kwh and offer an estimated energy density of 233 Wh/kg. Once Gigafactory production begins though, Tesla will be upgrading to new 20700 battery cells, which will be physically larger, capable of holding more energy, and thus requiring fewer individual modules. As battery chemistries and energy densities improve, battery electric vehicles could actually end up weighing substantially less than traditional internal combustion engine vehicles.
For battery electric vehicles to overcome the built-in advantages of vehicles rocking conventional internal combustion engines, many analysts point to battery costs as being the determining factor. But an article written for Seeking Alpha emphasizes that there may be another tipping point in the battery electric vehicles vs. internal combustion engines battle, and that’s the weight of the batteries themselves.
found on http://cleantechnica.com/2015/03/17/lighter-batteries-may-prove-tipping-point-electric-vehicles/