Title: A Phase-Field Model for Lithium-Ion Batteries

Speaker: Damian Burch, California Institute of Technology

Date/Time: Monday, March 9, 2009, 10:00 – 11:00 am

Location: CSRI/90 (NM)

Brief Abstract: Many of the static characteristics of a lithium-ion battery (open circuit voltage, Charge density, etc.) can be accurately calculated using thermodynamic and ab-initio techniques.  However, predicting how rapidly the energy can be delivered or how performance degrades over time requires a thorough understanding of the kinetics of Lithium ions inside the battery during use.  In this talk, I will present a phase-field model which can help us approach these problems for LiFePO4 and similar electrode materials.  Lithium diffusion in each particle is described using the Cahn-Hilliard equation (a 4th-order PDE), and ion exchange between the particle and the surrounding electrolyte are described by boundary conditions based on chemical reaction rate laws.  I will contrast this to existing models based on Fickian diffusion, and explain why the added complexity of our model is necessary.  I will then discuss how I solve these equations numerically, and present new results on multiple-particle interactions that cannot be predicted with any other existing model.

CSRI POC: Scott Collis, (505) 284-1123