In order to increase the cycle time of power batteries and decrease the overall cost of electric vehicles, the thermal management system equipped with heat pipes was designed according to the heat generated character of power batteries. The experimental result showed that the maximum temperature could be controlled below 50 degrees C when the heat generation rate was lower than 50W. Coupled with the desired temperature difference, the heat generation rate should not exceed 30W. The maximum temperature and temperature difference are kept within desired rang under unsteady operating conditions and cycle testing conditions. Applying heat pipes based power batteries thermal management is an effective method for energy saving in electric vehicles. (C) 2012 Elsevier Ltd. All rights reserved.