Study on bending-after-impact performance of composite sandwich structural batteries

• Impact and BAI tests of composite sandwich with embedded battery was performed. • Voltage evolution models for energy impact and bending-after-impact were established. • Impact damage and energy absorption characteristics were validated by numerical simulation. • The CSSBs exhibit excellent impact resistance and post-impact energy storage capabilities. Embedding lithium-ion batteries into composites creates a multifunctional structure that integrates the mechanical load-bearing capacity of composites with the energy storage and power supply of battery. Which effectively reduces the mass of currently available batteries and expands the usable space, presenting an ideal solution for next-generation energy transmission. Ensuring the mechanical load-bearing capacity and electrochemical stability of this structure after impact is crucial for its performance. This study investigates the impact response and residual performance of lithium-ion batteries embedded in composite sandwich structures. The force-electrical coupling behaviors during low-speed impact and bending-after-impact (BAI) were analyzed. Experimental results indicate that micro-short circuits may occur during the impact process of embedded lithium batteries, but they maintain good energy storage capacity during transient impact and BAI. Charge-discharge cycle tests show that with increasing impact energy, battery capacity damage increases, yet stable electrochemical performance is retained during bending. A developed numerical simulation framework validated the structural damage mechanisms under different impact energies, revealing the dynamic response and energy absorption characteristics of composite structures with embedded batteries. This study demonstrates that the composite sandwich structures with embedded batteries exhibit excellent impact resistance and post-impact energy storage capabilities, offering both theoretical and experimental support in new energy vehicles.