(207c) Modeling High Rate Lithium-Ion Batteries Using Fundamental and Empirical Methods

The power density of high rate lithium-ion batteries and lithium-ion polymer batteries is increasing yearly. To determine the viability of these batteries for powering various different types of electrically-powered devices, their performance under various conditions needs to be predicted/determined. We have measured the performance of commercially available high power cells from A123 under various temperatures and charge/discharge conditions. We have also used AC impedance spectroscopy to determine the equivalent circuits of these cells as a function of temperature and charge state. From the impedance measurements, we have developed empirically based models for these cells and the fidelity of these empirical models will be presented. Also, with the use of a commercial battery modeling software program, we have initiated the modeling of these batteries from a fundamental basis and the fidelity of these models will also be presented.