Electrochemical modeling is a key approach for detecting and diagnosing incipient faults in lithium-ion batteries. Despite its computational cost, the pseudo-two-dimensional (P2D) model enables high-fidelity multi-physics simulations and explicitly captures early degradation mechanisms such as solid electrolyte interphase (SEI) growth and metal dendrite formation, thereby providing a physics-based foundation for accurate state-of-health (SOH) estimation and incipient fault analysis.
In this work, a coupled SEI growth and metal dendrite growth model is developed based on the P2D framework and implemented in COMSOL Multiphysics. By incorporating both side reactions into the total volumetric current density, the model captures their coupled effects on overpotential, terminal voltage, and capacity degradation under incipient fault conditions. The SEI submodel is validated using public NMC battery SOH data, showing high accuracy across different aging stages. Parameters of the extended coupled model are further calibrated using a particle swarm optimization (PSO) algorithm and validated under dynamic load conditions, confirming the capability to reproduce battery degradation behavior.
