Preventing thermal runaway propagation in lithium-ion batteries: Model-based optimization of interstitial heat-absorbing thermal barriers

Advances in cathode and anode materials enable the energy density of lithium-ion batteries to increase further. However, safety concerns, particularly regarding thermal runaway propagation (TP), are intensifying. TP is a cascading reaction that occurs when a cell undergoing thermal runaway in a module triggers adjacent cells, leading to module destruction. Preventing TP is crucial, especially in applications like electric vehicles. This research introduces a method for designing safe battery systems using an interstitial barrier with a heat-absorbing effect to avert TP. For this purpose, a lumped element model parameterized by different methods is implemented to simulate the cell-to-cell TP inside a battery module. Comparison with TP tests on 3-cell modules of varying barrier thicknesses validates the model. The results exhibit effective TP prevention by the barrier, with TP occurring in just 41 s without it. Moreover, our model is able to predict the TP times from the experiments. Further, this work demonstrates a design strategy involving a barrier with optimal thickness for maintaining volumetric energy density while ensuring safety. Therefore, this work highlights the significance of a heat-absorbing barrier and demonstrates its optimal module integration using a validated simulation model to promote the development of safe batteries.