Homogenized Mechanical Modeling of Porous Anode Coating to Determine Swelling‐Induced Stresses Under Operational Conditions

Determining internal stresses in cylindrical lithium-ion batteries is crucial when silicon-based particles are added to the porous anode coating (PAC). A reliable homogenized constitutive model must be developed to capture both out-of-plane and in-plane mechanical properties of the PAC to perform efficient cell-level mechanical simulations where particle-resolved approaches are computationally impractical. We propose a complete, balanced, and cost-effective workflow designed for practical engineering applications. Out-of-plane properties are characterized by microindentation (MI) experiments, while a particle-resolved simulation-based design of experiments (DoE) serves as an efficient tool to determine the bulk in-plane behavior. Simulations indicate an effective Poisson’s ratio of the PAC bulk in a range from 0.2 to 0.39, which contradicts the zero Poisson’s ratio assumption in existing literature. Finally, these results are used to parameterize porous elastic and Drucker-Prager Cap (DPC) plastic models to estimate swelling stresses under fully constrained conditions. The model predicts out-of-plane stresses of 2.5–3.5 MPa and in-plane stresses of 1.5–2.5 MPa at 10% macroscopic swelling of the PAC, which align with empirical literature data. ... mehrThe proposed workflow demonstrates a highly balanced and readily deployable engineering methodology for a mechanical analysis on a cell level.