Investigation of propagation of thermal runaway during large-scale storage and transportation of Li-ion batteries

Thermal runaway in Li-ion cells and battery packs impacts the safety and performance of electrochemical energy storage systems. In particular, preventing the propagation of thermal runaway in large-scale battery storage and transportation of batteries is of much importance. While most of the past work in this direction addresses single cells or a small battery pack, only limited literature is available on systems of larger size. This work presents multiphysics simulations of propagation of thermal runaway during large-scale storage and transportation of Liion cells. Through simulations that account for multimode heat transfer, Arrhenius heat generation, turbulent fluid flow and combustion, the propagation of thermal runaway from one pallet of cells to an adjacent pallet is studied. The model quantitatively predicts the temperature field in/around the pallets, and, in particular, predicts whether the adjacent pallet will also catch fire or not. The impact of state of charge of the cells on thermal runaway propagation is examined. Results indicate that the gap between pallets plays a key role in determining propagation. A sharp threshold value of the gap is found, beyond which, propagation does not occur. Results from this work may be helpful in ensuring thermal safety during large-scale storage and transportation of Li-ion cells, ultimately contributing towards improved electrochemical energy storage and conversion.