Thermal Modelling of Fire Propagation in Lithium-Ion Batteries Using FDS

Lithium-ion batteries (LIBs) are a promising energy source for various applications and especially for electric mobility due to their high efficiency, high energy density, and long cycle life. However, the rapid rise of electric vehicles on the road has not been followed by an equally rapid development in the scientific knowledge of LIB fire hazards and technological solutions to predict it and mitigate them. Experimental tests of real-scale electric vehicles are quite limited and hardly consider the burnout of the cars. CFD simulations are a promising tool to model large fires in car parks and ferries based on parameters measured in small-scale tests. However, although CFD models of cars can be found in the literature, the inclusion of the battery pack contribution to the car fire is not trivial. This study outlines a methodology to model the fire spread from one LIB cell to another, which could later be extended to a whole battery pack to obtain a heat release rate (HRR) curve that can be added to that one of the car interiors to predict the HRR of an EV. In particular, the choice of the HRR of the single battery cell and its ignition temperature and the necessary mesh refinement required to predict the ignition of adjacent cell surfaces are highlighted.