Analysis of failure behavior and safety performance on sodium-Ion batteries under dynamic loads

Sodium-ion batteries(SIBS) have emerged as a promising candidate for energy storage applications owing to their material abundance and cost-effectiveness. However, safety concerns under mechanical abuse conditions remain inadequately addressed. This study systematically examines the failure mechanisms of commercial 18650 sodium-ion batteries under radial compression through integrated experimental and numerical approaches. A homogenized finite element model is developed to simulate dynamic crushing responses at impact velocities ranging from 1 to 35 m/s, with failure mechanisms elucidated through stress wave theory. Results demonstrate coincident peak load and failure points under quasi-static loading. Increasing compression velocity elevates peak load and failure displacement, while exhibiting negligible influence on temperature rise for batteries at 0% State of Charge (SOC). Under dynamic impact conditions, failure displacement decreases with impact velocity, showing a sharp decline beyond 20 m/s. Crack localization displays distinct velocity dependence: initiating at the central region for low velocities (<15 m/s), shifting to the bottom at 20 m/s, and transitioning to the impact end above 30 m/s. This behavioral transition is primarily governed by stress wave propagation and superposition effects. The study concludes that sodium-ion battery failure originates from structural instability-induced internal short circuits, with SOC dictating thermal behavior at low velocities while stress wave effects dominate high-speed failure characteristics. The established model demonstrates strong predictive capability for macroscopic mechanical responses, providing valuable insights for enhanced battery safety design.