Mechano-Electrochemical Model for Acoustic Emission Characterization in Intercalation Electrodes

Active particles inside the lithium-ion battery electrode experience diffusion induced stress and volume change during intercalation. High-rate or low-temperature operation can cause large concentration gradients resulting in higher probability of microcrack formation and propagation in the active particles and ultimately performance decay. Acoustic emission is a non-destructive technique for the detection of mechanical degradation. In this work, a computational methodology has been developed, based on a dynamic lattice spring model (DLSM), to study acoustic emission characteristics resulting from intercalation induced microcrack formation in electrodes. This method allows relating the acoustic response with the mechanical damage experienced during lithiation/delithiation in the active particles. Energy released due to brittle fracture is rendered as the major source of acoustic emission response. Predictions from this analysis suggest that during cycling maximum amount of acoustic activity is observed in the first couple of cycles. A phase map has been developed to demonstrate the influence of elastic modulus and damping coefficient on the damage evolution and identify a potential window of reduced mechanical degradation. (C) 2014 The Electrochemical Society. All rights reserved.