The most commercialized and successful LIB is based on the intercalation mechanism, which requires shuttling of Li-ion between anode and cathode with redox reaction occurring on the surface of the electrodes and ultimately leading to the Li-ions to diffuse into the host structure of the electrode. Such electrodes are naturally made to be porous, to maximize the surface area for redox and electrochemical reaction, also giving rise to multiple pathways for Li-ion diffusion and migration. These electrode structures are also integrated with additives to increase electronic conductivity and mechanical strength. This gives rise to the microstructure as a matrix of different phases with multi-length scale structures and characteristics at different scales. The performance and operation of the battery are closely intertwined with the electrode microstructure, and thus microstructural characteristics significantly influence the transport process or kinetics of the reaction. On the other hand, the wide-ranging application of the LIB requires them to have diverse energy and power-dense configurations. For these reasons, a battery module consists of LIB cells connected in parallel and series for various requirements.&nbsp;Traditionally LIB models have focused on studying the charge and discharge characteristics of a single cell as a function of the electrode structure. In this work, the focus is to develop high fidelity first principle models which are capable of accurately simulating spatial and temporal electrochemical physics and temperature of the module for different configurations of the cells. This model will be cognizant of the microstructure property of the electrode as well as the battery configurations. The development of such a physics-based model requires combining governing partial differential equations for different regions of the battery. This model will be capable of understanding the relation between performance and electrode microstructure, which considers the widely different structural arrangement of the phases altering the short- and long-range interactions within the electrode.&nbsp;We aim to utilize our model for studying the electrochemical performance and degradation mechanisms under scenarios wherein the module consists of either heterogeneously lithiated cells with the combination of the presence of thermal gradients. The inclusion of degradation mechanisms such as Li-plating will be beneficial in studying the most adversely impacted regions of a module. The model will also be trained and adjusted based on the experiments of cells cycled under different conditions. This combined experimental and computational modeling approach will allow us to precisely track down the physical mechanisms stemming from the Li-ion battery system.

Li-Ion Battery Pack Model

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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