Time: 2:00 PM, April 26, 2023 (Wednesday)

Place:台達館401室 Delta Building 401

Thermodynamic Modeling of Cycling-Induced Damage in Lithium-Ion Battery

鋰電池循環損傷的熱力學模型

Fuqian Yang

Department of Chemical and Materials Engineering

University of Kentucky, USA

Understanding structural durability and safety of metal-ion batteries, such as lithium-ion battery and sodium-ion battery, is of practical importance for applications in electric vehicles and hybrid electric vehicles. In this talk, I first present some results on diffusion-induced stress in the framework of elasticity. Following the method used in damage mechanics, I then introduce an isotropic damage state variable in the deformation analysis of electrode during electrochemical cycling for the analysis of cycling-induced damage. The evolution of the damage state variable is dependent on chemical reaction, reaction-released heat, and stress state of the electrode, and the elastic constants and the nominal molar volume of the electrode material are dependent implicitly on the damage state variable. An approximated expression is proposed for the damage states corresponding to individual cycle for respective insertion and de-insertion process. Assuming negligible effect of stress on insertion/diffusion of diffusive constituent, the effect of structural damage/degradation on the bending of an electrode beam is analyzed during the first insertion. The numerical results reveal that the structural damage/degradation reduces the minimum radius of curvature that an electrode beam can reach. There exists the damage-induced relief of the diffusion-bending moment that is introduced by the insertion of the diffusive constituent.

Biography of Dr. Fuqian Yang

Dr. Fuqian Yang (楊福前) is a professor in the Department of Chemical and Materials Engineering at the University of Kentucky. Dr. Yang has established a vigorous research program at the University of Kentucky in green synthesis of semiconductor nanocrystals, synthesis of ultrafine metallic materials, diffusion-induced stress, multiscale micromechanical testing and characterization, including nanoindentation, atomic force microscopy, microindentation, and dynamic mechanical behavior. He has proposed the concept of grain boundary fluid in analyzing the creep behavior of crystalline metals, developed the techniques of electrical impression test, electric indentation, and evaporation-induced surface structures on polymer films, and developed green routes for the synthesis of semiconductor nanocrystals. He has published more than 420 archival refereed journal papers. Dr. Yang is an associated editor for Journal of Manufacture Processes and a member of editorial board for Materials Science and Engineering A. He and Professor J.C.M. Li of the University of Rochester recently co-edited a book “Micro and Nano Mechanical Testing of Materials and Devices”, which was published by Springer in 2008.