Thermal runaway propagation (TRP) has become an urgent problem in the field of lithium-ion battery (LIB) fire safety, bringing potential risks to their large-scale applications. In this work, a novel strategy to prevent TRP of large-format lithium iron phosphate battery (LFP) module using aerogel, polyimide foam (PIF) and mica tape composite insulation cotton (MTCC) is proposed and investigated experimentally under two modules. One module consists. Thermal runaway propagation (TRP) has become an urgent problem in the field of lithium-ion battery (LIB) fire safety, bringing potential risks to their large-scale applications. In this work, a novel strategy to prevent TRP of large-format lithium iron phosphate battery (LFP) module using aerogel, polyimide foam (PIF) and mica tape composite insulation cotton (MTCC) is proposed and investigated experimentally under two modules. One module consists of three batteries with insulation placed in every other battery (Individual Insulation Module, IIM), and the other module has four batteries with insulation placed in every third battery (Spacer Insulation Module, SIM). The prevention effect of the interstitial materials is analyzed by changing the thickness and configuration type in two modules. In addition, the heat transfer from the front batteries to the last battery under SIM is calculated. The results show that both the aerogel and 2 mm PIF can prevent TRP, and the latter can reduce the heat transfer power from the penultimate cell to the last cell from 785.28 W to 314.2 W. However, PIF and MTCC with 1 mm thickness can only prolong the TRP time by 1351 and 1462 s, respectively. Modules with SIM configuration are less dangerous than those with IIM. The heat from the penultimate battery dominates the temperature rise of the last battery, while the heat transferred from other parts to the last battery only accounts for 10–19 % of the total heat.••••Novel module configuration is designed to explore the effect of insulation materials.••The preheat from the front batteries to the last battery is calculated.••2 mm thickness polyimide foam exhibits the most excellent insulting capacity.••The penultimate battery dominates the temperature rise of the last battery.Lithium-ion battery safetyThermal runaway propagationPreventionHeat transferCurrently, the problems of energy shortages and environmental pollution are becoming increasingly serious. Countries all over the world are vigorously developing new energy sources. As an advanced renewable energy storage medium, lithium-ion batteries (LIBs) are widely used in electric vehicles due to their high energy density, and excellent cycle performance. However, thermal runaway (TR) is likely to occur when LIBs are exposed to abuse conditions, releasing a large amount of heat and combustible gas, which easily causes fire and explosion,and brings hidden dangers to people's lives and property safety. A battery module may consist of thousands or hundreds of batteries. If no countermeasures are taken when TR occurs amid batteries, thermal runaway propagation (TRP) may occur, which is more dangerous.In recent years, there have been many studies on the TR mechanism of LIBs,,,,,,,. Huang et al. experimentally studied the TR of large-scale cell under two abuse conditions of overheating and overcharging and obtained its TR characteristics under different heating powers and overcharge rates, and they found that the TR caused by overcharging was more serious than that caused by overheating. Mao et al. conducted a series of TR tests on lithium‑iron phosphate batteries (LFPs) and studied their flame characteristics experimentally. Their experiment indicates that the toxic. 2.1. Battery sample and insulation materialBattery sample: A commercial prismatic lithium-ion battery with a nominal capacity of 280 Ah was investigated in this paper. The battery has two jelly rolls inside, with a size of 173.7 × 207.5 × 72 mm3. The electrodes are LiFePO4-graphite and its nominal voltage is 3.2 V. Its cut-off voltages for charging and discharging are 3.65 V and 2.5 V, respectively. Prior to the heating test, the battery was first discharged to 2.5 V with a constant current of 20 A and then charged to a 100 % state of charge (SOC) through the constant-current and constant-voltage method, and subsequently placed still for 24 h before the experiment.Thermal insulation material: The insulation materials used in this work include aerogel, PIF and MTCC. The thicknesses of the aerogel and PIF are 2 mm and 1 mm, respectively. It should be noted that the MTCC is a double layer structure and can be made by sticking mica tape on one side of the insulation cotton. These materials are summarized and shown in Table 1.Table 1. Properties of insulation materials.2.2. Module designAs shown in Fig. 1, all tests were conducted under two modules in this work. T.
