Battery Thermal Management Simulation - 1D+1D Electrochemical Battery and 3D Module Modeling on Vehicle System Level 2021-01-0757

Approaching engineering limits for the thermal design of battery modules requires virtual prototyping and appropriate models with respect to physical depth and computational effort. A multi-scale and multi-domain model describes the electrochemical behavior of a single battery unit cell in 1D+1D at the level of intra-cell phenomena, and it applies a 3D thermal model at module level. Both models are connected within a common vehicle simulation platform. The models are discussed with special emphasis on battery degradation such as solid electrolyte interphase layer formation, decomposition and lithium plating. The performance of the electrochemical model is assessed by discharge cycles and repeated charge/discharge simulations. The thermal module model is compared to CFD reference data and studied with respect to its grid sensitivity. The temperature evolution of a module is simulated for enabled and disabled degradation equations revealing a very high impact of the degradation equations when approaching engineering limits, which is demonstrated for the outbreak of a thermal runaway. A dedicated cold-start simulation additionally highlights the importance of multi-scale and multi-domain models when predicting the rate of lithium plating.