The battery is a critical component of an electric vehicle, as its operating temperature significantly impacts performance, lifespan, and safety. The best working environment temperature for the lithium battery is between 25–40 ℃, and the maximum temperature difference between each battery cell should be within 5 ℃. Therefore, a stable and efficient cooling system for the lithium battery pack is essential. This paper presents a numerical investigation of the indirect liquid cooling system for the battery pack. The battery cells were placed in contact with the wall of a serpentine cooling channel, which had wall thicknesses ranging from 0.7 mm to 1 mm. Water was pumped through the serpentine cooling channel at inlet velocities ranging from 0.03 m/s to 0.3 m/s. The cooling model was simulated using ANSYS FLUENT software. This approach enables the evaluation and selection of the optimal configuration, including the appropriate channel wall thickness and water flow velocity, to achieve energy efficiency while maintaining effective cooling.