BMS-oriented model for Li-ion batteries with mixed SiOx/graphite anodes

As new active materials are implemented in commercial cells, so must the mathematical models used in battery management systems (BMS) be updated. This is the case with the use of SiOx (0<; x<; 2) as anode material in Li-ion cells. In contrast with conventional graphite, Si-based materials present greater potential hysteresis between lithiation and delithiation. In the present paper, a compact model for batteries with a mixed Gr/SiOx anode is proposed. The model is composed of a fractional order transfer function and a two-storage OCP-submodel, in order to capture the SiOx/graphite interactions. The two-storage model lowered voltage rms error from 14.7 mV to 5.8 mV compared with a regular fractional model with hysteresis.