Study on thermal runaway characteristics and liquid nitrogen inhibition effect of large-format lithium-ion battery modules

Thermal runaway (TR) in lithium-ion battery (LIB) modules poses significant safety risks to energy storage systems, primarily due to the potential for thermal runaway propagation (TRP) between adjacent modules. This study investigates the influence of liquid nitrogen (LN) intervention on module-to-module heat transfer during TR events in a large-format prismatic LIB module. Experimental results demonstrate that, in the absence of LN, TR in the central module leads to significant heat transfer to adjacent modules, especially in the vertical direction, driven by buoyancy-induced flame ejection and hot gas flow. However, after LN injection, the heat transfer to neighboring modules is effectively suppressed, with the temperature of adjacent modules remaining near or below ambient levels, preventing further TRP. Comparative analysis of different LN injection masses (11 kg, 13 kg, and 18 kg) reveals that while larger LN quantities enhance cooling rates, excessive injection yields diminishing returns in heat absorption efficiency. A 13 kg injection is identified as the optimal balance, providing sufficient cooling to interrupt inter-module heat transfer and confine the thermal hazard within the initial failure module. These findings provide practical insights into the design of cryogenic suppression systems and structural safety measures aimed at limiting module-to-module thermal propagation in large-scale energy storage applications.