Lightweighting of Battery Electric Cars: An Impact Analysis Using Indian Driving Cycle 2013-01-2831

Mass reduction of vehicle is crucial for increasing fuel efficiency and reducing emissions so as to address rising environmental concerns. In case of battery electric vehicles, this will further augment the benefits in reducing the energy storage capacity required at a given electric drive range. The range of an electric vehicle depends on the stored energy in the battery pack and energy use by the vehicle. The energy use by a vehicle depends on several factors including vehicle mass, power train efficiency as well as driving cycle. Given a range requirement, vehicle's energy efficiency determines the energy storage required. A lighter vehicle will typically require a smaller battery for a given electric range, which in turn will result in energy savings. Hence, vehicle mass and battery mass are critical factors in energy efficiency of the vehicle.

In case of ICE vehicles, any unplanned increase in the mass of a component during vehicle design has a ripple effect throughout the vehicle; other components need to be resized increasing vehicle mass even more (termed as ‘mass compounding’). A more encouraging view of this behavior is considering a reduction in the mass of a component enabled by new technology resulting in a greater mass saving for the overall vehicle (termed as ‘mass decompounding’). In this case, secondary mass changes are considerable.

The same logic applies to battery electric vehicles also: primary mass change results in secondary mass change and the reduced compounded vehicle mass would reduce the battery energy capacity required to meet the same range requirement of the vehicle, thus reducing the mass of the vehicle further.

The present paper investigates impacts and benefits of Lightweighting of Electric Car. In the present case, the conventional steel car body is replaced with aluminum. A comparative lifecycle impacts in terms of energy consumption and emissions will be estimated using Indian Driving Cycle (IDC). A typical mid size sedan is chosen for the analysis.