Modeling Climate Control Loads and the Impact on Vehicle Range for Last-Mile Electric Delivery Trucks in Cold Climates
2022-01-0225
03/29/2022
- Event
- Content
- In cold climates, the cells in the battery of an electric vehicle are subject to environment-related performance degradation leading to a decrease in effective range. Cold ambient temperatures contribute to two primary sources of increased auxiliary power requirements – battery and cabin thermal management systems. Active battery temperature regulation is often implemented in battery electric vehicles (BEVs) to mitigate the detrimental effects of extreme temperatures on battery state of health and effective nominal capacity. At the same time, demands on heating, ventilation, and air conditioning (HVAC) systems increase in extreme environments to maintain driver comfort by regulating the cabin temperature. This paper presents a study to analyze and model increased auxiliary power demand from HVAC systems in cold climates. The developed model can be used to aid localized BEV range prediction. Practical driving data was periodically collected from an instrumented medium-duty internal combustion engine (ICE) delivery vehicle over several cold winter months in Minnesota, USA. A simplified empirical model to estimate HVAC power requirements was developed from relevant temperature and airspeed measurements within the vehicle. Time series drive cycle data was also collected to help evaluate vehicle performance, using road load equations to estimate powertrain demands from acceleration, ascent, aerodynamic drag, and rolling resistance. Using a physically similar BEV model for simulations, the effects of driving in a range of cold ambient temperatures on battery energy usage and effective vehicle range were assessed. The results show that reasonably accurate auxiliary power estimates (below 5% mean absolute percentage error) may be achieved through the proposed data-driven modeling approach. The proposed method for modeling HVAC power requirements serves to aid future researchers in isolating the correlated effects of ambient temperatures on battery performance degradation, and in evaluating the effectiveness of battery thermal management systems.
- Citation
- Eagon, M., Trujillo, J., and Northrop, W., "Modeling Climate Control Loads and the Impact on Vehicle Range for Last-Mile Electric Delivery Trucks in Cold Climates," SAE Technical Paper 2022-01-0225, 2022, .