Study on the Blocking Effect of Aerogel Felt Thickness on Thermal Runaway Propagation of Lithium-Ion Batteries

There is a poor blocking effect of the paper diaphragm used in the transportation package of lithium-ion batteries. Hence, researches on barrier materials are necessary. In this study, the thermal runaway (TR) was triggered by a heating rod and propagated horizontally between battery packs, and the tests were conducted in a self-designed chamber to investigate the blocking effect of aerogel felt thickness on the TR propagation of 18,650 lithium-ion batteries with 30% SOC and 100% SOC. And a simplified model of TR propagation was established to illustrate the heat propagation between batteries. The results showed that when the barrier thickness of aerogel felt increased from 1 to 10 mm, the number of batteries with TR decreased, the total heat release rate (THR) triggering time was longer, and the blocking effect of TR propagation was better. Besides, the aerogel felt the thickness of 1 mm had a poor effect on the prevention and control of TR, and there was a threshold between the barrier thickness of 6 mm and 10 mm to prevent TR. Simultaneously, there was a slight fluctuation in the parameters of heat release rate (HRR), battery surface temperature, and peak concentrations of CO and CO₂. And the concentrations of O₂, CO_2, and CO are related to the SOC and the number of TR of lithium-ion batteries. When the thickness of aerogel felt increased to a certain value, the difference between mass loss and the force effect produced by TR will be smaller, and the THR will be more. These results provide valuable proposals and inspiration for packaging in civil aviation transportation.