The development of electric vehicles is still hampered by excessive heat that occurs in electric vehicle batteries. Battery Thermal Management Systems (BTMS) are needed for thermal management that occurs in electric vehicle batteries. BTMS can reduce the negative impact of temperature on batteries. Various studies have been carried out to overcome overheating in electric vehicle batteries. One way that can be done is by using an electric vehicle battery cooling system. Utilizing Phase Change Material (PCM) as a cooling medium for electric vehicle batteries is one alternative that can be done. Many things can influence the effectiveness of battery cooling, including PCM material, PCM position relative to the battery, PCM shape, PCM dimensions, and so on. Of the several PCM materials being developed, paraffin material is a potential PCM material candidate for development, but this material has low thermal conductivity. The addition of other elements to paraffin can increase the thermal conductivity of PCM. In this research, an electric vehicle battery cooling system was designed using paraffin and TiO2 as PCM, with the hope of providing an effective battery cooling effect. From the research results, it is known that using PCM as a battery cooling medium can provide a better reduction in battery temperature compared to not using PCM cooling, and the addition of TiO2 as PCM to paraffin can provide better cooling compared to using pure PCM.