Li-ion battery performance and degradation in electric vehicles under different usage scenarios

Abstract

Summary Lithium-ion (Li-ion) batteries are well known as an efficient energy storage solution for plug-in hybrid electric vehicles (PHEVs). However, performance and state of health of these batteries strictly depends on the usage scenario including operating temperature, power demand profile, and control strategy imposed by the battery management system. Also, in PHEVs equipped with electric climate control systems, climate control loads are imposed as additional loads on the battery, which results in a reduced all-electric range (AER) and increased battery capacity degradation. In this paper, vehicle AER, and fuel economy and life degradation of an aftermarket LiFePO4 Li-ion battery cell are studied for a PHEV under several usage scenarios. Each scenario consists of a series and parallel PHEV powertrain layout developed in Autonomie software, climate condition, that is, hot and cold weather, and a daily driving and charging profile. For simulations, models of battery performance, heat generation, and degradation developed based on experimental results are integrated with a thermal vehicle cabin model. Impact of climate control loads and battery thermal preconditioning are incorporated in the simulations. It is observed that climate control loads significantly affect the AER (up to 20%), fuel economy (up to 65%), and battery degradation (up to 25%). On the other hand, thermal preconditioning could be used to reduce these impacts.