The research objective of this Grant Opportunity for Academic Liaison with Industry (GOALI) project is to establish a model for the evaluation of stress in a separator in a lithium ion battery. A separator is a membrane that prevents physical contact between the positive and negative electrodes while enabling ionic transport. The integrity of the separator is vital to the performance and reliability of a battery. In a lithium ion battery, non-mechanical stresses arise due to Li intercalation and self heating of the battery. A multi-scale multi-physics model will relate the deformation and stress in battery components to the material properties, design parameters and the battery electrochemical kinetics. The mechanical behavior of a porous polymeric membrane separator saturated with an electrolyte will be investigated experimentally and represented with an extended biphasic poroviscoelastic model.
The multi-scale model will enable the investigation of interactions among different physical processes and advance the understanding on degradation and failure mechanisms in lithium ion batteries. Besides the separator, it will also allow the optimal design of electrodes and battery cells. A durable, light weight rechargeable battery is a key requirement in producing affordable, sustainable electric and hybrid electric vehicles. The modeling approach and the porous viscoelastic model developed here are applicable to other devices and complex material systems. This project will encourage mechanical engineering students to participate in multi-disciplinary research. The findings will be developed into a demonstration for the College of Engineering "K-12 programs," at Michigan State University, to inspire the future generation of engineers.
