Simulation Of The Electrode Stress Within Square Lithium-ion Battery

Square lithium-ion battery has been widely used in various mobile portable devices. However, electrode stress occurring within the charging and discharging process can cause electrode damage and leads to battery capacity fade. Therefore, analysis of the electrode stress and thereby to obtain an electrode design optimization method, not only has important theoretical value but also has real practical significance.Firstly, the square electrode structure has been established. The corresponding governing equations, boundary conditions and the corresponding solving methods are given. Secondly, the lithium concentration and stress distribution under galvanostatic control were simulated. The effects of electrode curl on the lithium concentration and von Mises stress and the related mechanism are also discussed. Thirdly, the lithium concentration and stress distribution and their evolution under potentiostatic control are calculated. By comparing the results with the galvanostatic control, the optimized battery operation method was obtained, namely: galvanostatic control first followed by potentiostatic control. In addition, the effect of electrode curl radius and the elastic modulus of the active layer to the current collector on the lithium concentration and von Mises stress are also analyzed. Optimized design methods were given, namely: the curl radius should be larger than the thickness of the active layer, the elastic modulus of current collector to active layer should be smaller.