Simulation model to predict thermal runaway propagation of Li-Ion batteries in power tool applications

Cell thermal runaway (TR) refers to an exothermic reaction which causes the cell temperature to rise, thereby activating further exothermic reactions in an uncontrollable manner, resulting in the destruction of the cell. A consequence of this occurrence is the propagation in an uncontrolled manner of TR to the remaining cells in a battery pack. Safe battery pack against TR propagation is a key designing topic for all equipment manufactures incorporating battery packs in their systems. In this article a model capable of predicting the evolution and propagation of cell thermal runaway (TR) in a compact battery pack for handheld power tool applications is presented. Experiments were done at the single-cell and pack levels to confirm and evaluate the model’s accuracy. This model enables to compare and quantity the robustness of a particular pack design against TR propagation.