About the Dynamic Response of an Automotive Lithium‐Ion Battery Module Through Preliminary Finite Element Method (FEM) and Experimental Modal Analysis (EMA)

This study presents a combined experimental and numerical investigation of the dynamic behaviour of a commercial prismatic lithium-ion battery module. The primary objective was to characterise the module’s modal properties and to quantify how experimental choices and modelling assumptions influence modal identification and numerical validation. A preliminary finite element (FE) model–guided sensor placement and excitation strategy and an extensive experimental modal analysis (EMA) campaign, using instrumented hammer impacts and a limited number of accelerometers, provided time-domain and power spectral density (PSD) measurements. To improve robustness, modal frequencies from multiple tests were combined using coherence-weighted averaging. Results show a high modal density between roughly 400 and 550 Hz: the first three experimentally identified modes occur at ≈399 Hz (torsion), ≈478 Hz and ≈550 Hz (bending). The FE model reproduced the main modal patterns but exhibited a swap between the second and third modes, likely due to geometric simplifications and mass/stiffness approximations. The work also reports practical best practices for modal analysis at the module level (suspension strategy, impact location, hammer tip selection and sparse-sensor layouts) and discusses PSD/time-domain analysis for the chosen mode shapes. Finally, the module model provides a suitable foundation for future scale-up studies. In particular, the use of reduced-order models and superelements is identified as a promising approach to extend the methodology to full battery packs while preserving accuracy and limiting computational cost. The combined EMA–FEM approach provides actionable guidance for EV designers to avoid dangerous resonance bands in battery systems.