Power and Thermal Management with Battery Degradation for Hybrid Electric Vehicles

Abstract

This paper develops a framework for integrated power and thermal management of hybrid electric vehicles (HEVs) that explicitly manages tradeoffs between fuel economy and battery degradation. The total ownership costs and cradle to grave sustainability of electrified vehicles is strongly impacted by the health and lifespan of their batteries. However, most strategies for power management of HEVs focus on maximizing fuel economy, without explicitly considering the impacts of control decisions on battery health. Studies that have addressed tradeoffs in power management and battery health have not also taken thermal management systems and temperature-dependent battery degradation into consideration. This paper couples models of the powertrain, thermal management system, and battery degradation to optimize tradeoffs between efficiency and battery health. Dynamic programming is performed to provide an idealized benchmark for performance. Simulation results illustrate that a more informed balance between fuel efficiency and battery degradation can be achieved by including thermal management in the purview of the powertrain controller. A model predictive controller is then studied as a closed-loop strategy, based on the same formulation as the open-loop dynamic program.