Localized impact-resistant battery enclosures for electric vehicles: crashworthy lightweight design, mechanical–thermal safety, and validation pathways

Electric-vehicle battery enclosures must reduce structural mass while preserving deformation clearance, sealing integrity, electrical isolation, and post-impact safety. These requirements are difficult under bottom strike and side-pole collision because both load cases create localized intrusion near cells and modules, where only limited deformation space is available. This Mini Review synthesizes recent lightweight enclosure research through a scenario- and mechanism-based protection framework, rather than a conventional material-by-material catalogue, with specific emphasis on localized bottom strike and side-pole collision. The review links external impact loads to enclosure response, cell-level safety indicators, and post-crash thermal or electrical functions. Aluminum alloys, composite and hybrid structures, foam-filled members, sandwich panels, honeycomb cores, auxetic lattices, and bio-inspired absorbers are compared in terms of intrusion control, energy absorption, manufacturability, and coupled mechanical-thermal performance. The synthesis indicates that no single material family solves the design problem alone. Future enclosure design should combine local puncture resistance, progressive crush, load spreading, cell deformation limits, thermal propagation mitigation, repairability, and standards-based validation. Therefore, battery-enclosure lightweighting should be assessed through a staged protection chain: external localized loading, enclosure deformation, cell-level abuse indicators, and post-impact thermal/electrical safety.