0
research-article

Coupled Mechanical and Electrochemical Analyses of 3D Reconstructed LiFePO4 by FIB/SEM in Lithium-Ion Batteries

[+] Author and Article Information
Sangwook Kim

Mechanical and Aerospace Engineering Department, North Carolina State University, R3158 Engineering Building 3, Campus Box 7910 911 Oval Drive, Raleigh, NC 27695
skim49@ncsu.edu

Hongjiang Chen

Mechanical and Aerospace Engineering Department, North Carolina State University, R3158 Engineering Building 3, Campus Box 7910 911 Oval Drive, Raleigh, NC 27695
hchen30@ncsu.edu

Hsiao-Ying Shadow Huang

Associate Professor Mechanical and Aerospace Engineering Department, North Carolina State University R3158 Engineering Building 3, Campus Box 7910 911 Oval Drive, Raleigh, NC 27695
hshuang@ncsu.edu

1Corresponding author.

ASME doi:10.1115/1.4040760 History: Received April 09, 2018; Revised June 26, 2018

Abstract

Limited lifetime and performance degradation in lithium ion batteries in electrical vehicles (EVs) and power tools is still a challenging obstacle which results from various interrelated processes, especially under specific conditions such as higher discharging rates (C-rates) and longer cycles. To elucidate these problems, it is very important to analyze electrochemical degradation from a mechanical stress point of view. Specifically, the goal of this study is to investigate diffusion-induced stresses and electrochemical degradation in 3D reconstructed LiFePO4. We generate a reconstructed microstructure by using a stack of FIB/SEM images combined with an electrolyte domain. Our previous 2D finite element model (FEM) is further improved to a 3D multiphysics one, which incorporates both electrochemical and mechanical analyses. From our electrochemistry model, we observe 95.6% and 88.3% capacity fade at 1.2C and 2C, respectively. To investigate this electrochemical degradation, we present concentration distributions and von Mises stress distributions across the cathode with respect to the Depth of Discharge (DoD). Moreover, electrochemical degradation factors such as total polarization and over-potential are also investigated under different C-rates. Further, higher total polarization is observed at the end of discharging, as well as at the early stage of discharging. It is also confirmed that lithium intercalation at the electrode-electrolyte interface causes higher over-potential at specific DoDs. With these coupled mechanical and electrochemical analyses, the results of this study may be helpful for detecting particle crack initiation.

Copyright (c) 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In