A hybrid battery model and state of health estimation method for lithium-ion batteries

Lithium-ion polymer batteries are getting popular in both renewable energy systems and electric vehicles thanks to their high power and energy density. Therefore, accurate battery models are vital in design and simulation of hybrid/electric vehicle propulsion systems. In this work a novel equivalent circuit-mathematical battery model whose parameters were extracted from experimental data is proposed. Also a method was proposed in order to estimate battery cycle number using ECE 15 driving cycle and to obtain state of health (SoH) of a battery using the cycle number is introduced. The results of both evaluation of the model and the method were compared with actual results obtained from a series of experiments carried out using an automotive-grade 11Ah Kokam SLBP lithium-ion polymer battery.