To address the thermal management challenges in lithium-ion batteries-which are associated with safety, real-world driving, and operating cycles, particularly at high discharge rates and in extreme ambient conditions-it is essential to maintain the battery temperature within its optimal range. This work introduces a novel hybrid Battery Thermal Management System (BTMS) that integrating a Phase Change Material (PCM) and air cooling with fins attached to air-channel in PCM side. Unlike conventional approaches that use standard rectangular fins, this study employs angular fins with varying dimensions to enhance heat dissipation. The hybrid system is designed to leverage the high latent heat storage capability of the PCM while ensuring efficient convective heat removal through air cooling. The airflow through the cooling channel accelerates heat dissipation from the PCM, thereby increasing its effectiveness. The angular fins are strategically positioned within the PCM section to enhance thermal diffusion by increasing the effective heat transfer surface area. This study compares conventional fins with the proposed angular fin design to analyse the peak battery temperature and temperature variation across the battery. The optimized fin orientation with specific angles may enhance heat diffusion within the PCM. As the number of fin segments increases, the volume fraction occupied by the PCM is restricted, so the optimal number of fin segments must be evaluated for the best performance of the combined PCM and fin system. Our analysis of Fin - 3 (design 4) reveals its exceptional ability to maintain thermal uniformity across varying flow regimes. At a low velocity of 2 m/s, the PCM effectively homogenizes the temperature field, achieving the lowest temperature difference of 4.38 K. As airflow increases to 4 m/s, the system transitions to a convection-dominated state. In this regime, Fin - 3’s performance is sustained by a synergistic conduction-convection mechanism, achieving a minimum temperature gradient of 4.95 K. Furthermore, the proposed hybrid BTMS, under different conditions, may limit thermal stresses that develop within the battery. This research aims to improve battery thermal management with novel fin designs for next-generation systems.