Role of Stress Concentrations on the Electrochemical Response of a Li-Ion Battery Anode Particle

Abstract

Several numerical voltammetry simulations are used to evaluate the role of stress concentrations on the electrochemical response of an anode particle with geometric discontinuities. The effect of two-way stress-diffusion interaction, on the magnitudes of the mechanical stresses induced, is also estimated. Effects of stresses on electrochemical response increases (decreases) with the sweep rate when the particle was first discharged (charged). Stress concentrations are analyzed for several particle and hole sizes, and hole locations. It was found that the dependence of electrochemical response on stress is influenced more by the size of the hole rather than its position. When two-way interactions between stresses and diffusion were considered, the peak stresses induced were found to be 0.3 to 0.5 times the value induced when the influence of stress on diffusion was neglected. Overall, the study shows that stress-concentrations significantly affects the electrochemical behavior of a particle. Further, numerical modeling should include a two-way interaction between stress and diffusion so as to not overpredict stresses in an electrode particle.

Stress-Dependent Chemo-Mechanical Performance of Amorphous Si Anodes for Li-Ion Batteries upon Lithiation

“…Therefore, the concentration-dependent values of Ω Li should be considered in continuum models for an accurate prediction of chemo-mechanical behavior of a -Si anodes. Some recent theoretical studies also redefine the stress-dependent chemical potentials μ Li Si (σ ext ) that include the contribution of lithiation-dependent elastic softening in a -Li x Si. , Here, the contribution of elastic softening balances with the contribution of external stress, reducing the large underestimation of V ( x ). ,, The underlying connection between the concentration-dependent formation volume of Li and such elastic softening effect will be specifically investigated in our future work.…”

“…22,32 Here, the contribution of elastic softening balances with the contribution of external stress, reducing the large underestimation of V(x). 22,27,32 The underlying connection between the concentration-dependent formation volume of Li and such elastic softening effect will be specifically investigated in our future work.…”

“…Based on Larche and Cahn’s model, chemical potential simply relies on the hydrostatic stress, and tensile (compressive) stress contributes to the decrease (increase) in chemical potential of Li in a -Si anodes. , Such model reasonably explains the retardation of the lithiation process caused by compression. Other theoretical models of chemical potentials consider the contribution of large-strain deformation and stress-dependent mechanical properties. , In consideration of the electrochemical properties, it has been demonstrated that compressive stress combined with material stiffness remarkably reduces the battery capacity. , …”

“…Other theoretical models of chemical potentials consider the contribution of large-strain deformation and stress-dependent mechanical properties. 31,32 In consideration of the electrochemical properties, it has been demonstrated that compressive stress combined with material stiffness remarkably reduces the battery capacity. 33,34 In addition, atomistic simulations have been conducted to reveal the influence of external stress on the Li transport in a-Si anodes.…”

Mesoscale analysis of Li‐ion battery microstructure using sequential coupling of discrete element and finite element method

“…A few works highlight the effect of the mechanical stresses on the electrochemical response and underline the importance of including the stress terms in the chemical potential 33‐36 . There have been other works describing the detailed aspects of the numerical modelling of the active particles with the incorporation of stress‐diffusion effects 37‐41 …”