Coupled electrochemical-thermal-mechanical stress modelling in composite silicon/graphite lithium-ion battery electrodes

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Title: Coupled electrochemical-thermal-mechanical stress modelling in composite silicon/graphite lithium-ion battery electrodes
Authors: Bonkile, MP
Jiang, Y
Kirkaldy, N
Sulzer, V
Timms, R
Wang, H
Offer, G
Wu, B
Item Type: Journal Article
Abstract: Silicon is often added to graphite battery electrodes to enhance the electrode-specific capacity, but it undergoes significant volume changes during (de)lithiation, which results in mechanical stress, fracture, and performance degradation. To develop long-lasting and energy-dense batteries, it is critical to understand the non-linear stress behaviour in composite silicon-graphite electrodes. In this study, we developed a coupled electrochemical-thermal-mechanical model of a composite silicon/graphite electrode in PyBaMM (an open-source physics-based modelling platform). The model is experimentally validated against a commercially available LGM50T battery, and the effects of C-rates, depth-of-discharge (DoD), and temperature are investigated. The developed model can reproduce the voltage hysteresis from the silicon and provide insights into the stress response and crack growth/propagation in the two different phases. The stress in the silicon is relatively low at low DoD but rapidly increases at a DoD >~80%, whereas the stress in the graphite increases with decreasing temperature and DoD. At higher C-rates, peak stress in the graphite increases as expected, however, this decreases for silicon due to voltage cut-offs being hit earlier, leading to lower active material utilisation since silicon is mostly active at high DoD. Therefore, this work provides an improved understanding of stress evolution in composite silicon/graphite lithium-ion batteries.
Issue Date: 1-Dec-2023
Date of Acceptance: 2-Aug-2023
DOI: 10.1016/j.est.2023.108609
ISSN: 2352-152X
Publisher: Elsevier BV
Journal / Book Title: Journal of Energy Storage
Volume: 73
Copyright Statement: Copyright © Elsevier Ltd. All rights reserved. This manuscript version is made available under the CC-BY-NC-ND 4.0 license
Publication Status: Published
Embargo Date: 2024-09-03
Article Number: 108609
Online Publication Date: 2023-09-04
Appears in Collections:Mechanical Engineering
Dyson School of Design Engineering

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