Adaptability of Li-Ion Single Particle Model for Lifetime Simulation Using LFP and LMO Cells

摘要

For battery lifetime simulation and control, often a conflict between accuracy and the long simulation horizon arises. A single particle model (SPM) is therefore introduced, which combines the benefits of electrochemical models, which take internal states and concentrations into account, with time efficient empirical approaches in neglecting or averaging unimportant and CPU-intensive effects. Based on existing LiFePO4 (LFP) cell measurements and models by [1], an average SPM consisting of the basic cell kinematics and potentials, as well as a thermal and aging model is described. The aging model is based on solid electrolyte layer (SEI) growth, which is one of the main aging effects. Although such models already exist, they are often designed for one cell chemistry and with intensive measurements. The presented SPM is validated using LFP cell data and then adapted to fit other cell chemistry as well. It is shown that by merely adapting few parameters of the positive electrode using literature values as well as measured voltage, temperature and aging curves, the aging behavior of a LiMn2O4 (LMO) cell and possibly other Li-ion cell chemistry can also be predicted well. By adding a current and voltage dependent diffusion coefficient, also side effects like Mn-dissolution for LMO cells are implemented to improve the model.