Phase Change Material-based Battery Thermal Management System (PCM-based BTMS) has become a current research hotspot due to its high efficiency, thermal stability, and compactness. Regrettably, most existing research on PCM-based BTMS neglects the existence of mechanical vibrations, despite the inevitable involvement of such vibrations in the operating conditions of BTMS in electric vehicles. Therefore, in this study, a PCM-based BTMS is applied to a 6-cell lithium-ion battery (LIB) module, and then numerical simulation is employed to comprehensively evaluate the BTMS's performance in the existence of mechanical vibration. The findings indicate that, under mechanical vibration condition, mechanical vibration's influence on the performance of the BTMS is negligible at lower discharge rates, but becomes significant when the discharge rate surpasses a certain threshold, particularly at extremely fast discharge level, resulting in a decrease of 2.28 K in the LIB module’s maximum temperature and a more uniform temperature distribution upon completion of an 8 C discharge in contrast to its stationary equivalent. Furthermore, mechanical vibration only effectively enhances the BTMS’s thermal absorption capability when the PCM thickness surpasses a certain value, and this vibration also improves the capability of the BTMS to achieve uniform temperature distribution in the LIB module, especially for larger PCM thicknesses. Lastly, the BTMS's performance is able to strengthened by raising vibrational amplitude, but the impact is negligible when the amplitude is equal to or greater than 50 mm, and the thermal absorption capability of the BTMS can be augmented by raising the vibrational frequency, but there exists an enhancement limit. This work promotes the use of PCM-based BTMS in real-world applications and contributes to the advancement of LIB towards higher discharge rates.