A multi-physics thermal propagation model of a battery module, consisting of 507 cylindrical 18650 cells, was built using a commercial software. The model incorporated an empirical method for self-heating in battery cells, a 3-Dimentional (3-D) Finite Element method (FEM) for simulating thermal propagation in solid materials, and sub-models for thermal convection and radiation. Simulations reveal the significance of thermal convection in thermal propagation. The model agreed well with the experimental data until around half of the cells entered thermal runaway (around 22 minutes), with an observed overprediction of heat release afterward. This overprediction might be attributed to inaccuracies in thermal convection and the omission of burning vented gases and solid particles.
The Swedish Transport Administration and Stiftelsen Sveriges Sjömanshus are acknowledged through projectCarbon diOxide Fire Fighting Experimental Evaluation (number TRV 2023/33910 and FOU23-0016).