RC Equivalent Circuit Model Parameters Characterization

In the last decade, the equivalent circuit model has been utilized to model lithium-ion batteries for electric vehicle applications. Different researchers have proposed a variety of equivalent circuit models from simple to complex ones. The parameters required to describe and build these equivalent circuit models are being extracted from the Hybrid Pulse Power Characterization (HPPC) Test data.

This paper describes the process of the extraction of the equivalent circuit model parameters to build the battery models using different test methodologies such as HPPC and its modified versions. It also presents a case study with validated test results for a commercial light weight EV. Firstly, showing how the cell is characterized and then how the pack level cooling is developed to reach the required range based on an aggressive drive cycle. This is then integrated in to a full system level simulation to capture various interactions such as control pack and thermal behavior in the vehicle environment.