Abstract: Too low or too high operating temperature and excessive temperature fluctuations will adversely affect the output performance and durability of proton exchange membrane fuel cells． Therefore，effective thermal management is the essential to the stable and efficient output of proton exchange membrane fuel cells． In this study，a 1. 5mmthick vapor chamber was used as a heat dissipation structure in the thermal management of a proton exchange membrane fuel cell stack，and 80 thermocouples were installed on a cathode graphite plate with 5 single cells to obtain the internal surface temperature of cells，so as to explore the temperature distribution characteristics of the stack under different load currents． It’s found that，during the loading process of 0 ～ 8A，the maximum temperature difference of the cathodic side within each single cell is less than 1. 0 ℃，and local temperature fluctuation only occurs at inlet ports． In addition，the temperature distribution uniformity of the stack with vapor chamber is better than that of the ordinary water-cooled stack under the same operating condition．

Key words: proton exchange membrane fuel cell stack, thermal management, vapor chamber, temperature distribution