The second generation Volt has an upgraded powertrain with a 1.5-liter engine that uses regular gasoline; the 18.4 kWh battery pack has new chemistry that stores 20% more electrical energy and uses fewer cells, 192 compared with 288 on the 2014 Volt; it uses a new power controller that is integrated with the motor housing; the electric motors weigh 100 pounds less and use smaller amounts of rare earth metals.