Coupling of Mechanical Behavior of Lithium Ion Cells to Electrochemical-Thermal Models for Battery Crush: NREL (National Renewable Energy Laboratory)

Propagation of failure in lithium-ion batteries during field events or under abuse is a strong function of the mechanical response of the different components in the battery. Whereas thermal and electrochemical models that capture the abuse response of batteries have been developed and matured over the years, the interaction between the mechanical behavior and the thermal response of these batteries is not very well understood. With support from the Department of Energy, NREL has made progress in coupling mechanical, thermal, and electrochemical lithium-ion models to predict the initiation and propagation of short circuits under external crush in a cell. The challenge with a cell crush simulation is to estimate the magnitude and location of the short. To address this, the model includes an explicit representation of each individual component such as the active material, current collector, separator, etc., and predicts their mechanical deformation under different crush scenarios. Initial results show reasonable agreement with experiments. In this presentation, the versatility of the approach for use with different design factors, cell formats and chemistries is explored using examples.