Experimental and Modeling Study on Thermal Runaway Propagation Inhibition of Large-Capacity Lithium Iron Phosphate Batteries

在储能电池系统中，电池若遭遇热危险或机械危险，很容易诱发热失控现象。此时，电池会在短时间内迅速释放大量热量，进而引发系统内其他电池相继出现热失控。热失控过程中释放的高温气体在电池系统内部蕴蓄，可能引发爆燃，从而对电池系统的安全性构成严重威胁。本研究引入了一种砖砌式模组的隔热结构，使电池之间呈交错排列，降低了电池间的传热功率，达到隔断电池热蔓延的目的。针对大容量方形磷酸铁锂电池，开展模组密闭箱体实验以及建模研究。实验结果证实，在未使用隔热材料的前提下，砖砌式模组在抑制电池系统热失控蔓延方面具有显著的有效性。相邻电池的温度得到明显降低，热失控电池的热量被成功隔绝，有效阻止热失控热量向相邻电池传播。在密闭箱体内出现电池热失控后，为降低热灾害风险，喷发的高温气体需被排出，探讨高温环境对电池模组的影响。本研究建立了密闭箱体内的电池热失控高温气体喷发流动三维模型。该模型能模拟单节电池热失控后，高温气体在密闭箱体内的流动情况，为以后的储能系统安全结构设计提供重要的理论依据与设计思路，有助于进一步提升储能电池系统的整体安全性能。In energy storage battery systems, when batteries are subjected to thermal or mechanical hazards, they are highly susceptible to thermal runaway. During this process, batteries can rapidly release a large amount of heat within a short period, triggering subsequent thermal runaway in other batteries within the system. The high-temperature gases released during thermal runaway accumulate inside the battery system, which may lead to deflagration, posing a severe threat to the safety of the battery system. This study introduces a bricklaying-style module with an insulating structure, where batteries are arranged in a staggered manner. This arrangement reduces the heat transfer power between batteries, effectively interrupting the thermal propagation. Focusing on large-capacity prismatic lithium iron phosphate batteries, experiments and modeling studies were conducted using a closed-box module. The experimental results demonstrate that, even without the use of insulating materials, the bricklaying-style module is highly effective in suppressing thermal runaway propagation in the battery system. The temperature of adjacent batteries is significantly reduced, and the heat from the thermally runaway battery is successfully isolated, effectively preventing the spread of thermal runaway heat to neighboring batteries. After a thermal runaway event occurs in a closed box, to reduce the risk of thermal hazards, the high-temperature gases that are emitted need to be vented. The study investigates the impact of high-temperature environments on battery modules. A three-dimensional model of high-temperature gas ejection and flow inside a closed box during battery thermal runaway has been established. This model can simulate the flow of high-temperature gases inside the closed box following a single-cell thermal runaway event. It provides important theoretical basis and design ideas for future safety structure design of energy storage systems, and helps to further enhance the overall safety performance of energy storage battery systems.