In this research, two cooling plates with six parallel channels are designed for a twelve-cell battery module. The heat generated by a Li-ion battery cell is numerically modeled, and the numerical model is validated with the experimental data. The temperature difference of the battery cells in the battery module is an important factor for the capacity usage and cycle life of a battery module. The aim of this study is to design an optimum cooling system that will increase the cycle life of the batteries by decreasing the temperature difference and reducing the parasitic power consumption of the pump by reducing the pressure drop. The channel height, channel width, and the ratio of the outlet height to the inlet height are selected as design variables. In recent years, several evolutionary multi-objective optimization techniques have been presented to improve the performance of thermal management systems. In this study, CMOPSO is used for the optimization of the liquid cooling system. The results of the NSGA-II, NSGA-III, MOPSO, and CMOPSO techniques are evaluated to compare the efficiency of different optimization techniques. The results of four different multi-objective optimization methods are close to each other and have good agreement with the CFD results to reduce the temperature difference and pressure drop. A 30.3% decrease in the temperature difference and a 5.3% decrease in the total pressure drop are achieved with CMOPSO as the optimization technique. The results show the effectiveness of CMOPSO as the optimization technique for the design of battery cooling systems.