TY - JOUR
T1 - Electrochemical-mechanical modeling of solid polymer electrolytes
T2 - Impact of mechanical stresses on Li-ion battery performance
AU - Grazioli, Davide
AU - Verners, Osvalds
AU - Zadin, Vahur
AU - Brandell, Daniel
AU - Simone, Angelo
PY - 2019
Y1 - 2019
N2 - We analyze the effects of mechanical stresses arising in a solid polymer electrolyte (SPE) on the electrochemical performance of the electrolyte component of a lithium ion battery. The SPE is modeled with a coupled ionic conduction-deformation model that allows to investigate the effect of mechanical stresses induced by the redistribution of ions. The analytical solution is determined for a uniform planar cell operating under galvanostatic conditions with and without externally induced deformations. The roles of the polymer stiffness, internally-induced stresses, and thickness of the SPE layer are investigated. The results show that the predictions of the coupled model can strongly deviate from those obtained with an electrochemical model—up to +38% in terms of electrostatic potential difference across the electrolyte layer—depending on the combination of material properties and geometrical features. The predicted stress level in the SPE is considerable as it exceeds the threshold experimentally detected for irreversible deformation or fracture to occur in cells not subjected to external loading. We show that stresses induced by external solicitations can reduce the concentration gradient of ions across the electrolyte thickness and prevent salt depletion at the electrode-electrolyte interface.
AB - We analyze the effects of mechanical stresses arising in a solid polymer electrolyte (SPE) on the electrochemical performance of the electrolyte component of a lithium ion battery. The SPE is modeled with a coupled ionic conduction-deformation model that allows to investigate the effect of mechanical stresses induced by the redistribution of ions. The analytical solution is determined for a uniform planar cell operating under galvanostatic conditions with and without externally induced deformations. The roles of the polymer stiffness, internally-induced stresses, and thickness of the SPE layer are investigated. The results show that the predictions of the coupled model can strongly deviate from those obtained with an electrochemical model—up to +38% in terms of electrostatic potential difference across the electrolyte layer—depending on the combination of material properties and geometrical features. The predicted stress level in the SPE is considerable as it exceeds the threshold experimentally detected for irreversible deformation or fracture to occur in cells not subjected to external loading. We show that stresses induced by external solicitations can reduce the concentration gradient of ions across the electrolyte thickness and prevent salt depletion at the electrode-electrolyte interface.
KW - Battery performance
KW - Electrochemical-mechanical coupling
KW - Mechanical properties
KW - Partial molar volume
KW - Solid polymer electrolytes
UR - http://www.scopus.com/inward/record.url?scp=85056992139&partnerID=8YFLogxK
U2 - 10.1016/j.electacta.2018.07.234
DO - 10.1016/j.electacta.2018.07.234
M3 - Article
SN - 0013-4686
VL - 296
SP - 1122
EP - 1141
JO - Electrochimica Acta
JF - Electrochimica Acta
ER -