Geometry-Dependent Dynamic Impact Behavior of Lithium–Iron Phosphate Batteries at Different Velocities: An Experimental and Numerical Approach

The present work reports the drop weight impact tests with 18650 lithium–iron phosphate batteries (LFPB) at different impact velocities (1.04, 1.26, 1.36, and 1.69 m s⁻¹) at 0% and 50% state of charge (SOC). The investigation is extended for other battery geometry namely, 22650, 26650, and 32650. The thermal runaway triggering point is characterized by the event of internal short-circuit (ISC) resulting in voltage drop. The voltage drop phenomenon is ruled out to be present in the case of the tests at SOC 0%, while it is noticed for velocities 1.26 m s⁻¹ and above at SOC 50%. For SOC 50%, the voltage-time curve exhibits 87.5% and 21.2% drop corresponding to the highest and lowest impact velocity respectively. Further, the dynamic impact behavior is numerically simulated. The findings shows that the ultimate stress observed is maximum (0.53 MPa) for 32650 while it is minimum (0.47 MPa) for 22650 corresponding to SOC 0%. On the other hand, the ultimate stress is found to be maximum (0.68 MPa) for 22650 and minimum (0.47 MPa) for 26650. The outperformance of LFPB 26650 is observed in terms of its dynamic impact behavior.