Mechanical response of laterally-constrained prismatic battery cells under local loading 2020-01-0200
The crash safety of prismatic lithium-ion batteries has received great attention in recent years because of their growing popularity in electric vehicles. However, the safety issues of prismatic batteries have not been thoroughly studied, in particular, the mechanical responses of prismatic battery cells with lateral constraints under varied loading conditions remain unclear.
In this study, a fixture for lateral constraint based on the real packing situation in module is conducted to investigate the mechanical responses of prismatic battery cell in intrusion tests. Firstly, the effects of loading conditions, namely, the type and loading position of the indenters, and the impact speed, on coupled mechanical, electrical and thermal responses of prismatic battery cells are analyzed and discussed. Secondly, the influence of the side deformation of the impacted battery cell on the electrochemical performance of adjacent battery cells is studied. Therefore, the response of the packed batteries under local loading is revealed, which aims at helping the post-accident treatment of the battery module of electric vehicles. Thirdly, a simplified finite element model of packed prismatic battery cells model is used to describe the mechanical behaviors of laterally-constrained prismatic battery cells.
The results of intrusion tests indicate that the intrusion depth for the battery internal failure is affected by the side constraint conditions and the responses of battery cells vary under different loading speeds. Also the results of the simplified model have a good agreement with the experiment data. This study provides detailed mechanical responses of prismatic battery cell in vehicle crashes, which can be used in the determination of affected cells in the battery module under local loading and the judgement on replacement of the battery cells.