Empirical Modeling of Degradation in Lithium-ion Batteries and Validation in Complex Scenarios

Predicting capacity loss and resistance growth is essential to ensure battery cycle life is suitable for a given application. This paper presents an empirical aging model for NMC/graphite cells which is parameterized using data obtained from calendar aging and accelerated cycle aging experiments. The model was trained to predict degradation under stress factors including temperature (-5 degrees C, 25 degrees C & 45 degrees C), charging and discharging C-rates (0.2C, 1.5C & 2C), depth of discharge (50% & 100%) and storage at various states of charge (50% & 100%). The model was validated in complex scenarios such as cycling under varying temperatures and fast charging at 1.5C followed by a realistic daily drive cycle discharge.