| Proton exchange membrane fuel cell (PEMFC) has become one of the most important and popular research items in energy resource field due to its great advantages, such as high efficiency, no pollution, high power density and so on. The performance of subfreezing store, cold start and subfreezing durability is one of key issues in the commercialization of proton exchange membrane fuel cell, and so do they as a challenging frontier of fuel cell research. In this thesis, purge water and cold start through experiment and model.This thesis use dry air to purge water to investigate the effort of purge parameters. At present, subfreezing store and cold start and subfreezing durability have become a hotspot in PEMFC research. The prepurge used to control the initial water environment of single cell, and then carries on the cell cold start experiment. The main conclusions are as follows:(1) The water can be removed by twice dry air purge in the short time, and the performance of single cell is not damage by purge. In three purge methods( cathode/anode: 1.5/0.5,1.2/0.4,0.9/0.3NLPM), the water removal from anode is not changed with purge flow rate, but the water removal from cathode increase with the flow rate. So, the flow rate of anode could be low, and the flow rate of cathode must keep high. It must prolong the second purge time in low purge flow rate.(2) The ohmic polarization of PEMFC is influenced by the change of water content, and the performance of start is influenced by the change of ohmic polarization. The higher of twice purge flow rate is, while the lower of water content is, the higher of the resistance is, leading to the case that the longer period from single cell being started to its normal performance, the lower of the voltage. The single cell cold start could success by the flow rate set to anode 0.5NLPM and cathode 1.5NLPM. The temperature of single cell is constant during the progress of cold start. The performance of cold start can be optimized by purge parameters optimization.In addition, the purge parameters and cell parameters impact the effect of water removal base on CFD software. It found that the cell temperature is definitive, the purge speed is subordinate, and the impact of purge air temperature is considered negligible.The structure of fuel cells are different in cold start test, so the temperature rise rate are different in such test, and the dates doesn't have universal meaning. It is worth noting that the fuel cells have same performance in same temperature. The performance of isothermal start is connected with temperature rise, and it is universal meaning date. So the isothermal cold start performance below 0℃is analysed, and the isothermal cold start performance above 0℃is investigated by single cell. It found that the isothermal performance of single cell grows higher as cell temperature grows higher. The performance of activation polarization region upgrade little, ohmic polarization region upgrades more, and the concentration polarization region is unstable. In the range of 0℃-65℃, the overloading current density must be avoided in starting process in case it might reach the concentration polarization region at the specific temperature.
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