(Digital Presentation) Experimental Techniques for Parameterization of a Commercial 21700 Lithium-Ion Cell for Multiscale Battery Models

Abstract

Lithium-ion batteries have gained huge attention in the past few decades. Since its commercialization, a steady improvement in cost, and performance over the last 25 years has surfaced many new applications such as EV, HEV, etc., and growing popularity for military and aerospace applications [1, 2]. However, developing a safer, longer life, high energy, power-dense, and cheaper Lithium-ion battery requires a concerted research effort from various disciplines. For a long time, research was focused on developing the chemistry, but in the recent past, the improvement in the battery performance has been realized by reengineering the manufacturing processes and model innovation that help to understand the battery performance during the charging-discharging process. Battery models employed to optimize and predict battery performance are useful tools to design and manage batteries to ensure safe and efficient utilization. To understand the underlying physical, chemical, and electrochemical properties and precisely capture the cell dynamics in EVs application, the model should be based on fundamental governing equations of diffusion and migration processes as well as the kinetics of species intercalation.The physicochemical model requires precisely evaluated model parameters for the materials under consideration. Accurately measured kinetics and transport parameters will hold the key to deriving reliable conclusions about the internal state of a Lithium-ion battery. Parameter’s quantification is a challenging and time-consuming process that requires a range of characterization and analytical methods as shown in Figure. The battery modelling community usually borrowed the parameters list from the literature, with their origins not essentially being traced [3]. In literature, parameterizations have been reported for both high-energy and high-power cells for a physicochemical model [4-7]. This work employed several characterization techniques to parametrize a commercial Lithium-ion cell model. Also, various analytical methods were employed to determine the geometrical, chemical, and electrode microstructure as suggested in Figure. To determine the thermodynamic, kinetics, and transport properties of the extracted electrode materials different electrochemical tests, e.g., galvanostatic intermittent titration technique (GITT), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), constant current constant voltage (CC-CV) charge and constant current (CC) discharge were employed. The parameter’s accuracy would be investigated by validating the mathematical modelling simulation results with the experimental charge-discharge curves at different currents of the commercial 21700 cell at room temperature.