Modeling of internal mechanical failure of all-solid-state batteries during electrochemical cycling, and implications for battery design

Abstract

This is the first quantitative analysis of mechanical reliability of all-solid state batteries. Mechanical degradation of the solid electrolyte (SE) is caused by intercalation-induced expansion of the electrode particles, within the constrains of a dense microstructure. A coupled electro-chemo-mechanical model was implemented to quantify the material properties that cause a SE to fracture. The treatment of microstructural details is essential to the understanding of stresslocalization phenomena and fracture. A cohesive zone model is employed to simulate the evolution of damage. In the numerical tests, fracture is prevented when electrode-particle's expansion is lower than 7.5% (typical for most Li-intercalating compounds) and the solid-electrolyte's fracture energy higher than G c = 4 J m −2 . Perhaps counterintuitively, the analyses show that compliant solid electrolytes (with Young's modulus in the order of E SE = 15 GPa) are more prone to micro-cracking. This result, captured by our non-linear kinematics model, contradicts the speculation that sulfide SEs are more suitable for the design of bulk-type batteries than oxide SEs. Mechanical degradation is linked to the battery power-density. Fracture in solid Li-ion conductors represents a barrier for Li transport, and accelerates the decay of rate performance.

Fracture behavior in battery materials

“…Computational methods based on these crack initiation and crack propagation criteria can be used to predict the fracture behavior of materials. The phase field model [16][17][18]54] and cohesive zone model [55][56][57][58][59][60][61][62][63] are the most common computational models. The phase field model employs a continuous field variable to represent cracks.…”

Review: Characterization and Modeling of the Mechanical Properties of Lithium-Ion Batteries

“…The anisotropic model was more successful in predicting the short circuit, i.e., drop of force. It should be noted that materials used for the separator in this research (MAT-Piecewise-Plasticity and Mat-3-parameter-Barlat) are models for incompressible materials such as metal sheets, while as reported in the literature (e.g., [26]), the separator is a porous compressible layer.…”

An Online State of Charge Estimation Algorithm for Lithium-Ion Batteries Using an Improved Adaptive Cubature Kalman Filter

“…The lithium-ion battery's features include high energy density, a long lifetime, and a low self-discharge rate, and it accordingly has been widely utilized to be the energy storage system of plug-in hybrid electric vehicles (PHEVs) and pure electric vehicles (PEVs). However, its lifetime feature is well-known to be affected by many factors, such as charge/discharge current, temperature, unbalance in battery cells, depth of charge/discharge, damage evolution caused by the interaction of electrochemical and mechanical phenomena, and the cyclic charge/discharge process [1][2][3][4][5][6][7]. Therefore, in order to prolong the battery's lifetime as well as to ensure the battery operates reliability and safety, battery management systems (BMS) have to be developed to monitor and control the whole operating process of lithium-ion batteries [8].…”