Research on Two-Phase Flow Characteristics of Single/Dual-Cell 18650 Lithium-ion Batteries under Thermal Runaway

This study employs a three-dimensional computational framework to analyze particle effects on jet flames during thermal runaway of single/dual-cell 18650 lithium-ion batteries. Integrating Computational Fluid Dynamics with Discrete Particle Models , it examines particle-jet flame mixing characteristics, focusing on combustion behavior during particle eruption. Detailed performance maps and three-dimensional flame profiles were generated, including reactant mass fractions analysis. Findings show in initial thermal runaway, single-cell flames are lifted with half the height of dual-cell flames, which appear brighter and broader, while single-cells exhibit stronger eddy currents. During particle ejection, dual-cell configurations show less favorable particle velocities. The reaction zone for single-cell reactants is three times larger than dual-cells. In stable combustion, single-cell flames elongate uniformly whereas dual-cell flames concentrate near ventilation openings. These findings demonstrate significant differences in thermal runaway processes between battery configurations, providing crucial safety insights for battery assembly and integration.