A Predictive Model of Thermal Runaway Propagation Using Detailed Chemical Reactions for Cell Heat Release

Electrified vehicles require energy dense cells to meet customer requirements for range and performance. But increasing the energy stored in a cell also increases the energy released during a thermal runaway event. Thermal runaway in a single cell and the propagation to neighboring cells can cause the catastrophic failure of the battery pack and create a dangerous event for the vehicle occupants. Previous simulations of thermal runaway propagation have used imposed heat rates for the thermal runaway event. These heat rates are activated at a set average cell temperature. In this work the chemical reactions present in a thermal runaway event will be calculated to predict the thermal energy released during the event. These chemical calculations are linked to a thermal model to predict the temperature of both the runaway cell and the neighboring cells. The reaction rate in the neighboring cells will increase as the heat spreads from the runaway event so the model can predict the probability that the neighboring cells will also enter thermal runaway. The model will include cooling flows to predict the effect of various flow conditions on the cell reaction rates and runaway propagation.