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. The proposed workflow demonstrates a highly balanced and readily deployable engineering methodology for a mechanical analysis on a cell level.