Full Parameterization Study of a High-Energy and High-Power Li-Ion Cell for Physicochemical Models
Christina Schmitt, Martina Gerle, Dennis Kopljar, K. Andreas Friedrich
Abstract
For physicochemical modelling of lithium ion batteries, an extensive parametrization is necessary. These parameters need to be derived cell specifically as they vary with cell design. In this study, two cells from the same manufacturer are investigated which are optimized for high power and high energy applications. After opening the cells under argon atmosphere, the battery materials are extracted to conduct various chemical and physical measurements to define the active material type, microstructure, conductivity and mass loading of the electrodes. Furthermore, laboratory cells were built from the extracted materials to evaluate tortuosity and exchange current density by electrochemical impedance spectroscopy, open circuit voltages and solid diffusion coefficient by galvanostatic intermittent titration technique (GITT). The differences and similarities of these parameters for both cell types are discussed and compared to literature. Main differences are the electrode area, thickness, porosity, and thus, mass loading and areal capacity of the electrodes. Both cells have a NCA cathode, but only the high energy cell has a blend anode consisting of graphite and Si/SiO x whereas the anode active material of the high power cell is only made of graphite. The derived parameters are finally used for the parameterization of a P2D model.