batP2dFoam: An Efficient Segregated Solver for the Pseudo-2-Dimensional (P2D) Model of Li-Ion Batteries

An efficient solver for the pseudo-2-dimensional (P2D) model of Li-ion batteries is developed based on the open-source computational fluid dynamics platform OpenFOAM. Species and charge conservation equations are solved in a segregated manner: potential and concentration of electrolyte and solid electrode are solved sequentially. The non-linearity and interlinkage are handled by an iterative procedure. In the P2D model, solving Li-ion (de)intercalation in solid particles implicitly is time-consuming. The Picard method is employed for calculating solid concentration explicitly without the need to solve the discretized equations system. In one time step, Li-ion concentration of future time is recursively approximated until convergence. The explicit solving of solid concentration in combination with the overall iterative procedure makes solving of the P2D model efficient. Nonlinear source terms are linearized whenever possible to retain stability. Adaptive time-stepping is devised, grounded on the derivative of open circuit voltage (OCV) with regard to Li-ion concentration at the particle surface. The developed solver is validated in detail with respect to COMSOL. Performance under various operation conditions, such as discharge of rate 10 C, hybrid charge-discharge cycle, and urban dynamometer driving schedule (UDDS), demonstrates its robustness.