Experimental Investigation of Thermal Runaway Characteristics of Large-Format Li(Ni0.8Co0.1Mn0.1)O2 Battery under Different Heating Powers and Areas

This study experimentally investigates the effects of different heating powers and areas on the jet behavior and thermal runaway (TR) of 75 Ah LiNi0.8Co0.1Mn0.1O2 pouch lithium-ion batteries (LIBs) in an open environment. TR, a critical safety concern for LIBs, can occur under overheating conditions. The TR behavior of LIBs was characterized by flame behavior, temperature characteristics, mass variation, jet dynamics, and residue formations. The results reveal that the heating power density primarily influences the time to initiate TR. Lower power densities extend the heating time and require higher energy to induce TR, thereby exerting a more considerable impact on the battery. The heating area predominantly affects the input energy and the extent of damage. Larger areas lead to more stable jet flames, consistent peak temperatures ranging between 1000 °C and 1300 °C, and mass loss ratios ranging from 44% to 53% compared to 43% to 47% for small-area heaters. These findings provide references for the safety design of battery assemblies and the prevention of TR propagation, contributing to the safer monitoring of LIBs.