Lightweight research on front-end load-bearing structures for passenger vehicle range-extended powertrains: A review

The introduction of a range extender in extended-range electric vehicles (EREVs) significantly increases the overall vehicle mass. As the primary mounting carrier for the range-extender system, the front-end load-bearing structure plays a critical role, and its lightweight design directly influences the vehicle’s energy consumption, dynamic performance, and safety. Focusing on the key technical issues of lightweight design for this structure, this paper systematically reviews recent research progress. Firstly, based on the packaging characteristics of the range-extender system, the mechanical performance boundaries and design constraints of the front-end structure are defined. Subsequently, the technical pathways for lightweighting are summarized across three dimensions: materials, manufacturing processes, and optimization algorithms. The applicability of high-strength steel, aluminum alloys, and composites is compared, with a particular emphasis on the process advantages of integrated high-pressure die-casting (HPDC) aluminum alloys and the performance characteristics of heat-treatment-free materials. A progressive design framework spanning from conceptual topology optimization to detailed size optimization is summarized, along with the application of multi-objective intelligent optimization algorithms in scheme decision-making. To address the high-frequency vibration and elevated-temperature service environment induced by the range extender, the elastoplastic, creep, and fatigue constitutive models of die-cast aluminum alloys are further reviewed, providing theoretical support for numerical simulation and life prediction. Finally, based on the identified limitations of existing studies, future directions such as multi-physics coupled constitutive modeling and function-structure integrated design are envisioned. This paper aims to provide a systematic reference for the innovative design of front-end load-bearing structures in extended-range electric vehicles.