Advantages of 3d and 1d Modeling a Li-Po Battery for the Prediction of Overheating under Real Driving Conditions

1d multi-domain modeling is a powerful tool for the fast prototyping of battery packs for electric vehicles. It can help identify the optimal layout for structural and thermal aspects and then support the battery sizing process. On the other hand, its simplicity may fail whereas precise simulations are needed. For example, a catastrophic event such as the thermal runaway can be triggered by a local peak of temperature on a single cell of the battery pack and then spread to the others. For this reason, the surface temperature distribution of a battery is crucial, and 1d models provide only an average value. Conversely, 3d models can provide this information even if at higher costs, in terms of time and computational efforts. 3d models of a Li-Po battery are not common in the literature because of the high complexity of the internal structure of a cell and the availability of experimental data for validation. This paper follows a previous work where a 3d model of a Li-Po cell was presented and validated. Here, a preliminary design of a battery pack for an electric vehicle is first run with a 1d model to identify critical temperature conditions. Current profiles, characteristic of real driving conditions, are experimentally tested and used to validate the 1d model. Then, the 3d model is applied to the most critical conditions to evaluate the bidimensional temperature distribution on the surface battery. The temperature predictions of the two models are compared also using experimental data. The strengths and weaknesses of the models are evaluated to show how they can contribute to the battery pack design process.