The existing electric ATV in the Automotive Laboratory, P21 of UniversitiTeknologi Malaysia had left abandoned without any purpose due to the lack of a battery. Therefore, developing a battery pack for the electric ATV using the 40 Ah lithium-ion pouch cells can make the electric ATV functional again. To do this, the battery needs to be designed in a way that it can fit inside the cargo load of the ATV which is the space of the previous battery. Next, the capacity of the battery pack needed to be designed based on the requirement of the electric ATV existing in the automotive laboratory. The complete system of the battery must include cooling system, battery management system (BMS), charging system and the battery packaging. Finally, the objectives of this project are achieved whereby a good performance battery with 74 V 80 Ah of capacity equipped with cooling system, battery management system, charging system and battery packaging is successfully developed.