Experimentally exploring thermal runaway propagation and prevention in the prismatic lithium-ion battery with different connections

Thermal runaway (TR) propagation is a critical challenge in the safety application of lithium-ion batteries (LIBs). In this study, the battery modules with different connection modes are designed to reveal TR propagation mechanisms, and a passive strategy based on thermal insulation is proposed to inhibit TR propagation. The temperature, voltage, heat transfer of battery module, as well as the equivalent flux power during TR propagation are captured and analyzed. The batteries in parallel experience fiercer combustion and propagation in comparison with the batteries without connection, which is because the parallel connection mode intensifies the exothermic reactions inside the battery. Particularly, the energy from the former battery contributes to the dominant heat source for triggering TR of its adjacent battery, accounting for 52 %− 67 %. Compared to the module without connection, the module in parallel releases much higher heat flux to adjacent batteries, leading to shorter TR propagation time and severer TR propagation. Furthermore, the aerogel can completely prevent TR propagations with different connection modes. The average flux power of the former battery to its neighboring battery can be reduced from 400 W to 35 W by inserting aerogel. The results provide new insights into TR propagation mechanism and its prevention, which are beneficial to the safety design of battery modules. • Thermal runaway propagation and its prevention of batteries in parallel are studied. • The causes of fierce thermal runaway propagation in parallel batteries are revealed. • Thermal runaway propagation can be successfully prevented by thermal insulation. • The heat transfer and the equivalent flux power between batteries are quantified.