Simultaneous application of active and passive methods in cooling of a cylindrical lithium-ion battery by changing the size of the elliptical cavity filled with nano phase change materials

This article performs the numerical study of thermal management of a battery pack using active and passive thermal management methods. For the active method, a forced and laminar airflow is used in the battery pack. For the passive one, phase change material (PCM) is employed around all battery cells placed in the enclosure. The enclosure filled with PCM is elliptical. Four different enclosure models are examined by changing their small diameter. This study is performed when the passive method does not work by melting all PCMs and the active method works. The numerical study method is finite element method and the study is transient. The results demonstrate that the maximum temperature of the battery first enhances and then decreases by employing the active method. The time of the change in the battery temperature trend depends on the enclosure model. The quantity of liquid PCM and the ambient air temperature are also lowered when the active technique is utilized. The temperature of the battery and the quantity of molten PCM are reduced by using enclosures with smaller minor axes. Using cavities with bigger minor axes, on the other hand, increases the quantity of molten PCM and the battery temperature. Also, the air outlet temperature from the enclosure with larger dimensions is higher than other enclosure models.