An effective battery thermal management system (BTMS) is essential for controlling both the maximum temperature and the temperature uniformity of a battery module. In this study, a novel and lightweight BTMS for prismatic batteries based on a heat pipe is proposed. A numerical model is created to study the influence of heat transfer designs and other factors on the thermal performance of the BTMS, and the simulation results are checked experimentally. The results show that when the condensation section of the heat pipe is cooled by liquid, the maximum temperature of the battery (Tmax) is reduced by 18.1% compared with air cooling. Decreasing the coolant temperature can reduce T_max, but can also lead to an undesirable temperature nonuniformity. The T_max and the maximum temperature difference (ΔTmax) in a battery module both increase rapidly as the discharge rate rises. The Tmax and ΔTmax are lower than 40 °C and 5 °C respectively when the discharge rate of the battery is lower than 2C. Under preheating conditions in cold weather, increasing the temperature of the heating medium can improve the temperature of the batteries, but at the same time it can make the battery module's temperature more nonuniform, and also add to cost. The temperature of the heating medium should therefore be selected with care. It could be concluded that the above results can provide perspectives in designing and optimizing battery thermal management system.