This study introduced a hybrid thermal management system for a 4×4 cylindrical lithium-ion battery module, simulating New European Driving Cycle (NEDC) conditions. The system integrated water, phase change material (PCM), and fins for enhanced heat dissipation. The batteries, attached to an aluminium shell, incorporated PCM and a central coolant path. Fins were introduced between the coolant channel and Al shell to enhance heat transfer between batteries, PCM, and water. Comparative analysis against passive (PCM only) and active (liquid) cooling systems revealed the hybrid system’s superior performance. With a water flow rate of 2×10−8 m3/s, the system consistently kept temperatures below 50°C during charge-discharge cycles. Compared to active cooling, it achieved a significant temperature reduction of 18.47% and 5.01% after the charge and discharge processes. An intermittent cooling strategy further demonstrated its effectiveness in preventing thermal runaway (> 60°C) compared to the active cooling system. The proposed hybrid system demonstrated efficient thermal performance with low pumping power, suggesting its potential for multiple charge/discharge cycles.