This work presents the liquid cooling system for powered battery applied on electric vehicle (EV). The objective is to design a liquid cooling system for the battery pack. The work contains a brief introduction of the current development of the electric vehicles, highlighting the importance of the thermal management system of the battery system, which motivates the project. Followed by a deep marketing research, which contains the classification of batteries, cooling methods and heating methods. The bibliographical review points out the liquid cooling system is the best way for the current market considering the cost, performance and the reliability. Then design the CAD models, one is tab cooling, the other one is the side surface cooling.