Simplified layered model of pouch cell for varied load cases: An indentation and three-point bending study

Abstract

A bottom-up highly efficient and accurate layered model for lithium-ion battery (LIB) pouch cells subjected to indentation and bending is developed in this study. Compared to homogenized and detailed models previously reported, this simplified layered model meets demands among accuracy, calculation efficiency and physical interpretability under external loading with a mixed compression-tension stress state, such as three-point bending in length and width direction and indentation with numerous indenter sizes. A calibration flowchart from battery components, jellyroll structure to whole battery cell revealed the contribution of each individual component and structural mechanical behaviors to the overall mechanical behavior. For the first time, our current results reported that apart from characterization of mechanical properties of battery components, the stiffening effect from sub-atmospheric pressure within the packaging materials and adhesive tapes on jellyroll mitigate delamination among layers. Thus, much improved structural integrity was allowed. In addition, the effect of state-of-charge (SOC) was integrated into the simplified model, by adding SOC hardening effect to negative current collectors. This model can capture mechanical responses of LIB cells under compression and compression-tension stress state under real-world crash scenarios, without excessive computation efforts.