Moving Horizon Estimation based Unknown Input Observer for Lithium-Ion Batteries

Battery state estimation is the key function of the battery management system which relies heavily on accurate current measurements. However, for the newly designed intelligent batteries with a lot of sensors and controllers integrated, the current sensors are expensive and easily disturbed. To this end, this paper proposed a moving horizon estimation (MHE)-based unknown input state observer (UIO) for the lithium-ion batteries to estimate the states of the battery. First, a first order RC battery model is built in Simulink, based on which the state-space function is derived. Then, the parameters of the model are identified offline and the MHE-based UIO is designed. The proposed method is validated for the superiority in SOC estimation without knowledge of the load current.