In this paper, the issue of battery thermal management of cylindrical lithium-ion cells for electric and hybrid electric vehicles is studied. Hybrid concepts combining air and liquid cooling are examined in detail using numerical simulation. The first concept includes vortex generators and jet inlets to increase turbulence within the battery pack in order to improve mixing and air flow between adjacent battery cells as well as liquid jackets to each cell in order to improve temperature uniformity at the cell level. The second concept uses evaporative cooling by means of fiber channels soaked by a reservoir below the battery pack through capillary action. The results of the second concept indicated a significant improvement in the cooling at the pack level. The maximum temperature increase was reduced by ∼50% and the average temperature increase was reduced by ∼59%. The second concept removes the complexity of the multiple air-cooling passive techniques and eliminates the safety issue due to the leakage of liquid within the battery pack. It is beneficial in terms of thermal performance at both the cell level and pack level and the commercialization of the battery pack as it is much simpler and easier to implement.