Structural design of roof-mounted battery packs for thermal and vibration safety

Roof-mounted battery packs have attracted increasing interest in the design of electric buses, specialty vehicles, and heavy-duty vehicles because roof placement can preserve passenger space, reduce underfloor design constraints and enable modular service access. Meanwhile, roof location poses serious structural and safety demands. The increased mass alters modal behaviour, increases inertial loading during road-induced vibration and increases design challenges of rollover resistance, enclosure retention, thermal control, venting, and thermal-runaway containment. This review is concerned with the structural design of roof-mounted battery packs with a particular focus on thermal safety and vibration safety. Major themes include enclosure design, roof-frame reinforcement, modal and fatigue design, cell-to-module packaging, passive and active thermal control, thermal-runaway propagation barriers, and regulatory or scenario-based validation mechanisms. The reviewed literature suggests that safe roof-mounted integration depends on combined optimization of stiffness, mass, damping, cooling strategy, spacing, insulation, and pack-to-body interfaces, indicating that optimizing a single parameter in isolation is insufficient. However, persistent weaknesses remain in coupled thermo-mechanical modelling, vibration-based thermal design and roof-specific testing under rollover, fatigue, and abuse conditions. This area is also highly important because electrified public transit and heavy-duty platforms to have structurally efficient, thermally resilient, and structurally robust battery systems that can be used over long service lives under harsh dynamic loading.