Structural Designs for Electric Vehicle Battery Pack against Ground Impact 2018-01-1438
Ground impact caused by road debris can result in very severe fire accident of Electric Vehicles (EV). In order to study the ground impact accidents, a Finite Element model of the battery pack structure is carefully set up according to the practical designs of EVs. Based on this model, the sequence of the deformation process is studied, and the contribution of each component is clarified. Subsequently, four designs, including three enhanced shield plates and one enhanced housing box, are investigated. Results show that the BRAS (Blast Resistant Adaptive Sandwich) shield plate is the most effective structure to decrease the deformation of the battery cells. Compared with the baseline case, which adopts a 6.35-mm-thick aluminum sheet as the shield plate, the BRAS can reduce the shortening of cells by more than 50%. Another type of sandwich structure, the NavTruss, can also improve the safety of battery pack, but not as effectively as the BRAS. As for the other two designs, the double-layered plate using two different aluminums is almost the same as the monolithic baseline case, and the enhanced housing box is even worse than the baseline. According to the comparison, it is concluded that the global deformation pattern of the whole structure can provide more safety than the local pattern. To further investigate the underlying mechanisms, scaled BRAS and NavTruss samples are manufactured using 3D-printing and tested under axial compression loading. Results show that the BRAS structure can avoid buckling and therefore provide a stable resistance force, leading to a high crashworthiness.