Mitigation strategy for Li-ion battery module thermal runaway propagation triggered by overcharging

The popularity and development of alternative energy vehicles have drawn critical attention to thermal safety concerns. The occurrence of fire and explosion due to thermal runaway propagation (TRP) has become a hurdle in developing new energy vehicles. Therefore, to study the TRP behavior of modules subjected to overcharged electrical abuse, we built a 1 × 5 pouch Li-ion battery module TRP model that combines a P2D electrochemical model and a 3D thermal runaway model. We present a complete analysis of TRP characteristics by examining TRP behavior under various design parameters such as thermal runaway trigger temperature (TTR), cell spacing (L), thermal conductivity (K), and heat dissipation coefficient (h). Increasing TTR can delay TR in each cell, effectively slowing the propagation speed, and TRP is prevented at TTR = 583 K. As L increases, the TRP is considerably extended, but TR in the overcharged cell is shortened. The higher K has a delaying impact on the TR of the overcharged cell but leads to a noticeably shorter TRP time. Higher h slows TRP and prolongs TR trigger time of the overcharged cell. We also investigated the intrinsic mechanism of TRP suppression by performing a heat flux analysis and screening several critical cases for TRP suppression. TRP's actual condition is delineated along a criticality line, distinguishing between propagation and non-propagation phases, and confirmed by experimental validation of typical TRP, critical TRP, and non-TRP cases. Furthermore, we studied the parameters requirement for battery module thermal management in the non-TRP region. These findings provide valuable insights for enhancing the safety design of battery systems and mitigating heat-related hazards.