Under high-intensity usage, an effective thermal management system is essential to control battery pack temperature within the desired range to guarantee battery safety and ensure a proper life cycle. This study developed a pulsating heat pipe (PHP) based thermal management system to promote battery temperature control. The system was tested for a large battery pack (2 kWh) under mild and severe ambient conditions via ANSYS Fluent simulation. A sensitivity study identified optimal PHP dimensions regarding the battery pack. The performance of PHP for both small and large scales was also evaluated. The system's effectiveness was compared to classical battery thermal management (BTM) systems such as forced air cooling, sidewall water cooling, and traditional heat pipes. The results demonstrated that the developed PHP-based passive cooling system effectively controls temperature, saves space, and reduces power consumption.