Study on mechanical characteristics of lithium-polymer pouch cell battery for electric vehicle

In order to characterize deformation and failure behaviors of Lithium-Polymer pouch cell battery and its components, various mechanical tests were performed. Uniaxial tensile properties of electrodes, separator, and pouch cover were obtained from coupon tests. Effects of temperature and strain rate on the mechanical behavior were also investigated. The three-point bending tests with and without pouch vacuum were performed to quantify the stiffening effect due to the pouching vacuum as well as quantifying the bending rigidity and failure load of the pouch cell. Static and dynamic pin drop tests were also carried out to investigate the failure mode and impact energy threshold for the perforation. The vibration responses, i.e., natural frequencies of pouch cell were obtained from impact hammer and shaker excitation tests. A finite element model of pouch cell using shell and membrane elements was also constructed. The same number of stacking layers in separator/electrode assembly was represented in the model. The solid state electrolyte that occupies very tiny volume between layers in the pouch was modeled by tied option of which the normal and shear moduli were calibrated from the three-point bending simulation.