Mechanical behaviors of battery electrodes under microparticle high-speed impacts

The mechanical behavior of battery components under high strain rates is crucial for understanding the electrochemical failure of lithium-ion batteries under extreme mechanical abuses. This study overcomes the limitations of conventional methods by utilizing the laser-induced micro-particle impact test for characterizing the ultra-high strain rate impact (up to 10⁶/s) of current collectors and active coatings for the first time. Here, a systematic investigation was conducted on the mechanical responses and failure mechanisms of LiFePO₄ cathode coatings, graphite anode coatings, copper foil, and aluminum foil under high strain-rate loading. Experimental results show that the failure mechanisms of current collectors were plastic deformation, brittle fracture, and petaling fracture. The active coatings underwent plastic deformation and brittle fracture accompanied by cracks, particle shedding and spattering. We further established corresponding FEM impact simulation models and modified parameters in the simplified Johnson-Cook model for collectors and the foam model for active coatings. The modified models have high accuracy and can effectively reproduce the experimental results, providing a precise description of dynamic mechanical behaviors for current collectors and active coatings under high strain rates. These studies provide a theoretical basis for numerical analysis of batteries' mechanical properties and failure prediction under high-speed impact.