储能用磷酸铁锂电池热失控分析及液氮抑制效果研究

Thermal runaway analysis and liquid nitrogen suppression effects in lithium iron phosphate batteries for energy storage applications

锂离子电池在使用过程中易受外界环境因素影响而触发热失控,此类现象不仅具有不可预测性,而且一旦发生,后果严重且难以控制,特别是电池的荷电状态(SOC)对于热失控的影响尤为显著。鉴于此,通过对比不同SOC条件下锂离子电池热失控特性并对其实施液氮喷射冷却处理,旨在探究其在封闭环境中的热失控行为特征。本研究还对电池箱进行了保温处理,以探究保温处理对液氮冷却效果及抑制电池热失控能力的影响。研究发现,SOC的提高与电池热失控引发的火灾规模、质量损失幅度以及产生的CO含量之间存在正相关关系。触发热失控的临界温度随SOC的增加而降低,而热失控峰值温度随之升高。电池热失控特征时间差值Δt与SOC成正比。对电池箱施加保温处理后,液氮的冷却效果得以显著延长,为延缓甚至抑制热失控提供了有效手段。

Lithium-ion batteries are susceptible to thermal runaway when exposed to external environmental influences during operation.This phenomenon,inherently unpredictable,can lead to severe and challenging-to-mitigate consequences,particularly as the State of Charge(SOC)markedly influences the onset and severity of thermal runaway.In this context,our investigation delves into the thermal runaway behaviors of lithium-ion batteries across a spectrum of SOC conditions,employing liquid nitrogen injection for cooling within a controlled environment.Moreover,this research extends to evaluating the impact of thermal insulation on battery enclosures,aiming to assess its contribution to enhancing the efficacy of liquid nitrogen cooling and the overall suppression capabilities against thermal runaway.The study elucidates a direct correlation between increased SOC and the magnitude of fire incidents,mass loss,and carbon monoxide generation during thermal runaway incidents.It was observed that the critical temperature threshold for initiating thermal runaway decreases with an elevation in SOC,whereas the peak temperature experienced during thermal runaway escalates.The duration to reach thermal runaway,time to peak temperature,and the differential in characteristic timescales exhibit a proportional relationship with SOC.Implementing thermal insulation treatments on battery enclosures demonstrated a notable extension in the cooling effects of liquid nitrogen,maintaining a prolonged cooling action on batteries undergoing thermal runaway.This significantly enhanced cooling duration effectively contributes to strategies aimed at delaying or even preventing thermal runaway,offering a viable approach to mitigating the risks associated with lithium-ion battery operations.