Fraunhofer Institute for Transportation and Infrastructure Systems IVIState Estimation
Next to variables such as current, voltage and temperature, which are directly measured by a battery management system (BMS), non-measurable state variables such as state of function (SOF), state of charge (SOC) and state of health (SOH) are equally necessary for the operation of a battery system. They give the users information about a storage unit’s currently available performance and energy level. In addition, they can be used to predict the remaining life span, safety-relevant events and premature system failures.
The algorithms used for the prediction of the aforementioned state variables are based on electro-thermal models of the cells used and are adapted to their respective applications. The Fraunhofer IVI develops methods beyond the established state estimation approaches, allowing the robust determination of state variables under consideration of all known cell characteristics. A further goal is to always ensure that the implementation is resource-friendly in terms of computation and storage requirements.