Performance quantification of latest generation Li-ion batteries in wide temperature range

Abstract

In addition to electric vehicles and stationary applications, Li-ion cells are now used in power systems of more electric aircrafts thanks to their high energy and high power density. Nevertheless, the available performance of Li-ion cells is limited at low temperature. This work is focused on the capacity and discharge resistance to evaluate the performance of last generation Li-ion technologies covering the range of aeronautic temperature (−20°C to 55°C). A dedicated method is proposed to determine the Open Circuit Voltage (OCV) and the discharge resistance at several States of Charge (SOC) and different temperatures. The self-heating is investigated during the continuous discharge which depends on internal resistance and heat transfer coefficient in climatic chamber. In addition, a quasi-static isothermal electrical model is carried out to rebuild the curve of continuous discharge for one technology by using the OCV and the discharge resistance at −20°C and 55°C. Finally, the difference between simulation and experiments is discussed and attributed to SOC quantification method with regard to discharge resistance measurement.