Thermal performance of an active battery thermal management system combining annular thermoelectric coolers and phase change materials

To achieve the optimal operating temperature for cylindrical lithium-ion batteries, a novel battery thermal management system has been designed, integrating annular thermoelectric coolers with phase change materials. Furthermore, a numerical model has been developed to provide an accurate analysis of the system's cooling performance, taking into account the coupling characteristics of fluid, thermal, and electric fields. The findings suggest that increasing the number of annular fins, enhancing the mass fraction of expanded graphite in the phase change material, and raising the annular thermoelectric cooler operating current can effectively improve the system's cooling performance. However, an overly high expanded graphite mass fraction can lead to premature melting of phase change materials, causing a rapid rise in battery temperature. Moreover, excessively high annular thermoelectric cooler operating currents can sharply reduce the contribution of phase change materials in battery thermal management, leading to higher system power consumption. Accordingly, to achieve optimal battery operating temperature and minimize power consumption, the best system configuration includes eight annular fins, the phase change material containing a 12 % expanded graphite mass fraction, and a thermoelectric cooler operating current of 0.8 A. Under these conditions, the maximum temperature is kept below 321.01 K, and the temperature difference is controlled within 3.41 K. These results offer valuable insights into the application of the thermoelectric-based battery thermal management system for cylindrical lithium-ion batteries.