Volkswagen is testing a super-battery, but how should they use its powers?
It is no secret that electric vehicle batteries are at an inherent disadvantage compared to the energy storage capabilities of gasoline. While 1 kilogram of gasoline holds about 43 MJ of energy, 1 kilogram of the average lithium-ion battery today holds about 150 Wh of energy, or just 0.54 MJ (although it should be noted that the 2014 Kia Soul EV can store 200 Wh/kg, and the Model S battery to be produced at the future Gigafactory is likely around that value if not higher).
This means that every unit weight of gasoline carries about 80x the energy of a battery. Therefore, to store the energy equivalent of a 15-gallon tank of gas, a typical lithium-ion battery would have to weigh about 7,000 pounds. Though electric vehicles are far more efficient than conventional vehicles and can recover energy through braking, to achieve the same range as a vehicle with a 15-gallon tank of gasoline an electric vehicle would still need a battery weighing in the neighborhood of 1,500 to 2,000 pounds.