A table-driven Li-ion battery model for a BMS development platform - modeling, measurements, implementation and validation

In this paper a simulation environment for the development of battery management systems (BMS) with respect to Lithium-ion cells is presented. This platform should allow for the verification of the suitability and of the interaction between selected hardware components (Li-Ion batteries and semiconductor circuits for battery monitoring), and of the software of a battery management system (BMS) by simulation. The necessary mathematical models for an equivalent circuit model (ECM) based on the theory of passive electric elements are developed. It contains a general system of nonlinear ordinary differential equations to describe the dynamical behavior of Lithium-ion with respect to internal voltages U i , i = 1,...,n, temperature and the state of charge SOC and the cell temperature T. The parametrization of the cells was carried out on the base of CIT (Current Interruption Technique) measurements in an Accelerating Rate Calorimeter (ARC) at different temperatures T and SOC in the time domain with a Least-Squares approach and subsequent optimization. From the parametrization look-up tables are created which are needed for the model implementation in the software. The models have been implemented in the modeling language SystemC AMS using the lookup-tables. The validation was performed with a current profile for an electric vehicle based on a NEDC (New European Driving Cycle) velocity profile.