A three-dimensional numerical analysis was conducted to examine the impact of Reynold’s number on a liquid-cooled battery thermal management system. The findings indicate that the battery’s temperature rises with increasing charging/discharging current rates. To address this issue, a numerical model was developed, utilizing a mini-channel to extract heat from the battery through water circulation. The model evaluated the temperature variation at Reynold’s numbers of 10, 50, and 100, assessing their impact on pumping power and contact thermal resistance. To ensure accuracy, the three-dimensional numerical model of conjugate heat transfer with the battery model was validated against previous works, enabling the determination of temperature variation, contact thermal resistance, and pumping power. The results indicated that a Reynold’s number of 50 proved to be the most efficient for high current discharges up to 6C. Additionally, the proposed cooling system demonstrated that cooling half of the surface on a single side of the cell efficiently maintained the battery’s maximum temperature within 325 K. Overall, the study showcased the potential of the mini-channel-based battery cooling system as a lightweight, robust, and cost-effective solution.