【摘要】 随着储能锂离子电池的大规模应用，电池热失控（thermal runaway,TR）过程中的气体扩散行为及其早期检测受到广泛关注。对280 Ah磷酸铁锂电池进行外部加热触发的热失控实验，系统分析了热失控过程中释放的气体成分，并探讨了不同荷电状态（state of charge,SOC）下的热失控特征。实验结果表明，高SOC条件下，电池热失控触发时间短，表面温升速率更高，100%SOC电池热失控释放气体中的H₂占比高达44.84%。相较之下，低SOC电池的热失控过程较缓和，主要释放CO₂（0%SOC电池热失控释放气体中CO₂占比78.41%）。此外，利用ANSYS Fluent软件对储能系统中磷酸铁锂电池热失控过程中气体的扩散行为进行了模拟。仿真结果表明，不同SOC条件下，气体扩散路径存在显著差异：在高SOC下，气体主要沿垂直方向迅速上升并在顶部区域扩散，而在低SOC下，气体首先在底部积聚，随后逐步扩散至整个空间。揭示了SOC对磷酸铁锂电池热失控特征及气体扩散行为的影响，为锂离子储能系统的安全优化设计提供了重要的理论参考。更多还原

【Abstract】 With the large-scale application of lithium-ion batteries for energy storage,the gas diffu‐sion behavior during thermal runaway（TR） and its early detection have received extensive attention.Thermal runaway experiments were conducted triggered by external heating on 280 Ah Li Fe PO₄bat‐teries,the gas compositions released during the thermal runaway process were analysed,and the characteristics of thermal runaway under different states of charge（SOC） were explored.The experi‐mental results show that under high SOC conditions,the thermal runaway triggering time of the bat‐tery is short,the surface temperature rise rate is higher,and the proportion of H₂ in the thermal run‐away gases released from 100% SOC batteries is as high as 44.84%.In contrast,the thermal runaway process of low SOC batteries is more moderate and mainly releases CO₂（78.41%of CO₂ in the ther‐mal runaway release gas of 0% SOC batteries）.In addition,the diffusion behavior of gases during the thermal runaway process of lithium iron phosphate batteries in energy storage systems was simulated using ANSYS Fluent software.The simulation results show that there are significant differences in the gas diffusion paths under different SOC conditions:under high SOC,the gas mainly rises rapidly along the vertical direction and diffuses in the top region,whereas under low SOC,the gas first accu‐mulates at the bottom and then gradually diffuses to the whole space.The influence of SOC on the thermal runaway characteristics and gas diffusion behavior of lithium iron phosphate batteries was revealed,which provided an important theoretical reference for the safe and optimal design of lithium-ion energy storage systems.更多还原