A Single Particle Model for Lithium-Ion Batteries with Electrolyte and Stress-Enhanced Diffusion Physics

Abstract

A low-order battery model has been developed that incorporates stress-enhanced diffusion and electrolyte concentration distribution into a modified single particle model. This model addresses two important challenges of battery modeling for Battery Management Systems: accuracy and computational efficiency. The developed model improves accuracy by including the potential drop in the electrolyte based on the predicted li-ion concentration profile along the entire electrode thickness, and by including the enhanced diffusivity due to diffusion-induced stress. Incorporating analytical solutions into a conventional single particle model eliminates the need to sacrifice calculation efficiency. The voltage prediction by the proposed model is more accurate than the conventional single particle model. Compared to complex physics-based battery models, the proposed model significantly improves the computational efficiency of various discharge scenarios, including constant current, the Dynamic Stress Test, and the Highway Fuel Economy Test. Integrating mechanical responses into the single particle model not only increases model accuracy, but also makes it applicable to models for next-generation high energy density materials where mechanical volume changes are important.