Deformation Analysis on In-Plane Loading of Prismatic Cell

The collision accidents of electric vehicles are gradually increasing, and the response of battery cell under mechanical abuse conditions has attracted more and more attention. In the real collision, the mechanical load on battery generally has the following characteristics, including multiple loading directions, dynamic impact and blunt intrusion. Therefore, it is necessary to study the mechanical response and deformation of battery under complex loading, especially in-plane dynamic loading condition. According to the actual accident, we designed the constrained blunt compression test of the battery in different speeds and directions. For out-of-plane loading, the structural stiffness of battery increases obviously and the fracture is advanced compared with the corresponding quasi-static tests. For in-plane constrained loading, the force response can be approximately divided into two linear segments, in which the structural stiffness increases abruptly after the inflection point. Besides, the response inflection point is advanced under the in-plane dynamic loading condition. A detailed finite element (FE) model was established for further analysis, including separator, current collector, anode coating and cathode coating. The jellyroll of in-plane loading will undergo two stages: bending deformation and compaction. The analysis of the simulation shows that the elements below the indenter will enter the compaction state in advance under high-speed loading, which leads to the inflection point in advance. The intrusion speed could affect the bending deformation, only forming shear kinks at the ends of jellyroll. This makes the deformation under dynamic loading different from quasi-static loading. Consequently, our findings can provide a reference for the safety design of the actual collision of the battery package and module.