Failure Analyses of Cylindrical Lithium-Ion Batteries Under Dynamic Loading Based on Detailed Computational Model

Abstract

Electric vehicles, powered by electricity stored in a battery pack, are developing rapidly due to the rapid development of energy storage and the related motor systems being environmentally friendly. However, thermal runaway is the key scientific problem in battery safety research, which can cause fire and even lead to battery explosion under impact loading. In this work, a detailed computational model simulating the mechanical deformation and predicting the short-circuit onset of the 18,650 cylindrical battery is established. The detailed computational model, including the anode, cathode, separator, winding, and battery casing, is then developed under the indentation condition. The failure criteria are subsequently established based on the force–displacement curve and the separator failure. Two methods for improving the anti-short circuit ability are proposed. Results show the three causes of the short circuit and the failure sequence of components and reveal the reason why the fire is more serious under dynamic loading than under quasi-static loading.