Electrochemical and thermal behavior simulation of sodium-ion batteries under different charging conditions: experimental validation and model analysis

This study investigates the operational characteristics of sodium-ion batteries through a combination of experimental validation and simulation analysis. The charge-discharge curves obtained from experiments and simulations demonstrate a high degree of agreement, confirming the accuracy of the electrochemical-thermal coupled model. Using this model, the study analyzes key parameters such as electrolyte salt concentration, solid-phase sodium concentration, and temperature distribution under different charging rates (C-rates) and states of charge (SOC). Results indicate that higher C-rates exacerbate electrolyte salt concentration gradients, hinder ionic transport, and increase non-uniformity in solid-phase sodium distribution, reflecting diffusion limitations. Temperature simulations reveal significant thermal gradients and localized hotspots during high C-rate charging, emphasizing the need for effective thermal management. These findings provide a comprehensive understanding of the internal dynamics of sodium-ion batteries and highlight the importance of optimizing design and operational parameters.