Set-based state of charge estimation for lithium-ion batteries

Batteries, in particular lithium-ion batteries, are one of the dominant energy storage devices, especially in the field of electric mobility. However, the long-term, safe and robust operation of batteries requires accurate estimates of battery parameters and states, and most importantly of the state of charge (SOC). The estimation of these quantities is difficult due to measurement uncertainties, model mismatch and parameter variations, as well as nonlinearities and large operating regimes. We present a method for set-based estimation of the SOC of lithium-ion batteries. The set-based estimator takes measurement and parameter uncertainties explicitly into account and provides a set of consistent states. The performance is compared to an electrochemistry-based observer employing a detailed distributed model for a realistic drive cycle.