Ambient and Initial Temperature Effects on Battery Electric Vehicle (BEV) Range and Energy Consumption Rate Modeled in FASTSim

Ambient and initial temperatures have a significant impact on the energy consumption rate of battery electric vehicles (BEVs) due to auxiliary loads and the dependence of battery efficiency on temperature. Quantifying these impacts can help BEV owners, communities, and researchers understand and prepare for the impact of temperature on BEV vehicles, especially as adoption increases. We used NREL's FASTSim 3 to investigate the impacts of a two-dimensional design-of-experiment that swept ambient and initial temperature in simulating a compact BEV hatchback over UDDS (city) and HWFET (highway) US EPA drive cycles. Compared to a 22 ° C ("cozy") initial / ambient temperature baseline in UDDS, a cold initial / cold ambient temperature (-7 ° C) resulted in a 221% increase in the energy consumption rate, a cozy initial / cold ambient temperature resulted in a 94% increase, a hot initial (45 ° C) / hot ambient (40 ° C) temperature resulted in a 40% increase, and a cozy initial / hot ambient temperature resulted in a 20% increase. These results show that initial temperature has a somewhat stronger impact on energy consumption rate and that both hot and cold initial and ambient temperatures significantly increase the energy consumption rate, with the greatest impact seen for cold temperatures. This is at least partially attributable to the fact that BEVs have much more efficient powertrains that generate very little waste heat. Batteries also store much less overall energy than a traditional gas tank because this efficiency enables a reasonable nominal range under average ambient conditions. These results can be used to better anticipate BEV energy consumption during weather events and in extreme climates.