Designing the side frame of an electric-vehicle battery enclosure for oblique pole impact

The side frame of an electric-vehicle battery enclosure must absorb pole-impact energy before the battery modules are damaged. Enclosure optimisation studies usually limit intrusion into the cell zone and so treat any contact between frame and modules as failure. This study examines how that choice changes the optimal frame. A subsystem model of an enclosure section under a 32 km/h, 75° oblique pole impact was built in the open-source explicit solver OpenCourant. The aluminium model was validated against axial-crush tests on AA6063-T5 extrusions (mean crushing force and absorbed energy within 9%), and the modules were represented by homogenised blocks calibrated against published module indentation tests. Frame wall thickness, number of frame cells and tray and cross-member thicknesses were varied in 61 simulations, combined with Kriging surrogates and NSGA-II. Under the no-contact criterion a single-cell frame was lightest, but by no more than 3%. Under a damage criterion of 5 mm module indentation the ranking reversed: the single-cell frames absorbed 16–23% less energy before module damage, and a two-cell frame with 3.2 mm walls raised this energy by 28% for 12% more mass. Frames whose peak force before module contact exceeded about 130 kN damaged the modules earlier, so their energy fell although their mass rose. This stiffness limit persisted when the module strength was varied by ±33%. Tray and cross-member thickness changed the result by less than 4%. All input decks and scripts are openly released