Date of Award
Open Access Dissertation
John W. Weidner
As the automotive industry moves towards large format electric vehicles, such as trucks and SUVs, the need for highly efficient, energy-dense electrodes rapidly increases. Several promising active materials have been studied and proposed, however, many of these materials undergo significant volume change upon lithiation and de-lithiation. Cell and pack designers struggle to understand and predict how active material volume change at the particle scale will affect mechano-electrochemical behavior on the electrode, cell, and pack scales. Additionally, many of these active materials suffer in their cycle life due to a mechanically-driven degradation of the electrode matrix. Therefore, the focus of this work is to develop a multi-scale model that accounts for relationships between mechanical and electrochemical phenomena at each scale in the battery system.
The resulting model establishes three novel improvements to the field of mechano-electrochemical battery modeling: (1) A representative volume element model was incorporated into standard battery models to generate realistic predictions of mechanical behavior in the battery cell and pack. (2) Thermodynamically non-ideal, lithiation-based volume change behavior of the active materials was accounted for in the model, leading to higher accuracy in simulations of pressure and cell strain and a stronger understanding of how anode/cathode capacity balance impacts volume change. And (3) a mechano-electrochemical model of a blended electrode was developed, bringing a better understanding of how active materials preferentially lithiate and the resulting effects on mechano-electrochemical behavior of the cell.
Pereira, D. J.(2021). Development of a Multi-Scale Mechano-Electrochemical Battery Model. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/6799