Spectral Analysis of Electric Vehicle Dynamics for Battery Eccentricity Using a Full-Car Model under Random Road Excitation

Electrical-vehicle (EV) dynamics are significantly influenced by battery mass and the location. Therefore, the combined investigation of a 7-DoF model, random road excitation, and eccentric battery effects is necessary for more accurate characterization of vehicle dynamics. In this study, a 7-DoF EV full-vehicle model considering battery eccentricity is derived to examine the coupled heave–roll–pitch vibrations under random road excitation. A spectral method is employed for the solution. EV response spectra are obtained using the power-spectral-density (PSD) of road roughness and the EV frequency-response-functions (FRFs). RMS values of response are investigated for different battery eccentricities and vehicle speeds [1-160km/h]. The results show that the normalized RMS varies up to ~30% total with EV speed and battery eccentricity. The highest RMS occur at vehicle speeds where the natural frequency is excited, while the lowest vibration RMS is obtained at low battery eccentricity on the x-axis. The developed EV model and solution method have been presented as a successful tool for investigating random vibrations and vehicle dynamics.