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 41s 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.