Validation of a Lumped Electro-Thermal Model of a 14S1P Battery Module with 3D CFD Results

A lumped electro-thermal model for a battery module with 14 cells in series (14S1P), and with a cooling channel, is created by two-way coupling of an equivalent circuit model (ECM) and a linear time-invariant (LTI) method based thermal reduced order model (ROM). To create the ROM, a step response data in the form of temperature versus time curve is required. This data is obtained by running a transient full three-dimensional (3D) computational fluid dynamics (CFD) analysis for the full module. The thermal ROM accounts for the effect of the heat generated by the active cells, the joule heat generated in tabs and connectors, and the coolant inlet temperature. To create an ECM, data from hybrid pulse power characterization (HPPC) test is used. Such a lumped electro-thermal model for a battery module can run faster than a 3D CFD analysis and can be easily integrated in a system level model. A 3D electro-thermal conjugate heat transfer (CHT) CFD analysis of a battery has high accuracy and fidelity, but it can be difficult to implement in a system level simulation. Hence, it is important to establish the accuracy of the lumped model by comparing with the 3D CFD results. Results from the lumped model are compared with the results from a 3D CFD simulation for a drive cycle. The lumped model results are within 1.6% of the CFD results. Also, the lumped model runs in a few seconds for a complete drive cycle making it a suitable model for a system level simulation.