Circuit modeling is an efficient method for analyzing early-stage faults in lithium-ion batteries. It simulates key aging mechanisms while balancing detail and computational speed. For early degradation, the model explicitly captures two critical faults: SEI growth using a 1RC equivalent circuit and metal dendrite growth using a transmission line model.
Our research develops a coupled model of SEI growth and metal dendrite growth within this circuit framework. By formulating model components as functions of key electrochemical parameters, it captures the distinct electrical effects of both degradation modes on terminal voltage. The metal dendrite growth model, represented by the transmission line circuit, is validated with long-term aging data, effectively capturing gradual resistance increase. Parameters for the extended coupled model are calibrated using a genetic algorithm and validated against experimental voltage data. The close match between simulation and measurement confirms the model’s ability to reproduce degradation behavior, providing a computationally efficient foundation for incipient fault prediction and future online diagnostics.
