Composite structural batteries (CSBs) integrate energy storage units into composite laminates, endowing the system with both mechanical and electrochemical functionalities. This multifunctional architecture holds great promise for lightweight design and reliability in automotive and aerospace applications. In this study, we investigate the impact resistance of CSBs and elucidate their degradation mechanisms under low-velocity impact (LVI), which remain inadequately understood to date. Compared to conventional carbon fibre (CF) laminates, CSBs retain appreciable load-bearing capacity under impact loading, with insignificant loss in global mechanical performance. The embedded cell components partially absorb compressive stress waves, reducing initial crack formation, but also introduce severe interlaminar delamination and tensile failure. Impact-induced microstructural damage significantly impairs charge transfer, intensifying polarization. Electrochemical tests demonstrate that CSBs in working condition are more vulnerable to impact, exhibiting prolonged polarization, voltage dip and internal resistance increase. The residual strength of CSBs after impact is markedly lower than that of CF laminates with more complex failure modes. A detailed 3D finite element simulation visualizes the impact-induced local micro short circuit leads to a transient surge in current, then the lithium concentration increases and potential drops. This study provides a foundation for the design, fabrication, and damage assessment of CSBs by elucidating their coupled electro-mechanical degradation behaviour, thereby supporting their broader application across diverse engineering fields. • Reveals electro-mechanical degradation of carbon fibre–LFP structural batteries. • Links impact-induced damage to electrochemical loss via tests and FE modelling. • Provides a framework for safer, impact-tolerant batteries in electric vehicles.
Mao et al. (Sun,) studied this question.