Temperature-Dependent Battery Models for High-Power Lithium-Ion Batteries

In this study, two battery models for a high-power lithium ion (Li-Ion) cell were compared for their use in hybrid electric vehicle simulations in support of the U.S. Department of Energy’s Hybrid Electric Vehicle Program. Saft America developed the high-power Li-Ion cells as part of the U.S. Advanced Battery Consortium/U.S. Partnership for a New Generation of Vehicles programs. Based on test data, the National Renewable Energy Laboratory (NREL) developed a resistive equivalent circuit battery model for comparison with a 2-capacitance battery model from Saft. The ADvanced VehIcle SimulatOR (ADVISOR) was used to compare the predictions of the two models over two different power cycles. The two models were also compared to and validated with experimental data for a US06 driving cycle. The experimental voltages on the US06 power cycle fell between the NREL resistive model and Saft capacitance model predictions. Generally, the predictions of the two models were reasonably close to the experimental results; the capacitance model showed slightly better performance. Both battery models of high-power Li-Ion cells could be used in ADVISOR with confidence as accurate battery behavior is maintained during vehicle simulations. Introduction Solid battery pack performance in hybrid electric vehicles (HEVs) is critical to the vehicle’s performance and energy management strategies. Accurate battery models are needed for control strategy development and general HEV simulations. At the National Renewable Energy Laboratory (NREL), as part of the U.S. Department of Energy’s (DOE) HEV Program, we have developed and validated battery models for our ADvanced VehIcle SimulatOR (ADVISOR) (1-3). Models for various battery chemistries used in ADVISOR are based on a resistive equivalent circuit model.