The objective of this research is to aid in the development of advanced Lithium-Ion batteries for electric and hybrid electric vehicles. In the end we want to have a chemistry dependent dynamic Li-Ion battery electric model on cell level for the modeling of real time behavior: i.e. evolution of voltage and current as a function of operating regime. The modeled behavior will be a function of material and design parameters making it possible to direct battery design based on the requirements, and afterwards, to extend the model to other compounds on the positive and negative electrode. This testing-simulation approach will not be limited to the prediction of transient battery characteristics, but will also monitor the ageing effects.
More specific, the objective of this research is to develop a rigorous physics-based model for NMC based Li-Ion cells which can estimate energy and power capacity, real-time response, cycle-life, capacity fade and ESR increase and this in relation with the materials used and cell design. From this model, which is a non-linear system of coupled differential equations, an Equivalent electric Circuit model (EC) can be derived in a certain operating point. The incentive for the latter is twofold: the parameters in the equivalent circuit are relatively easy determined via electrochemical impedance spectroscopy. Given that in this case they are a function of material and design parameters, they will provide a benchmark for used values of these parameters. Secondly, starting from the rigorous model we will determine the EC model parameters, applicable for a certain working point: SoC, SoH. Until now this can only be done by testing the battery over the full range of these conditions.