Font Size: a A A

The Mechanism Study Of Operating Parameters On Local Performance Of PEMFC With Deadended Anode

Posted on:2024-05-11Degree:MasterType:Thesis
Country:ChinaCandidate:X Y LiFull Text:PDF
GTID:2531307097971189Subject:(degree of mechanical engineering)
Abstract/Summary:PDF Full Text Request
Proton Exchange Membrane Fuel Cell(PEMFC)is a highly efficient,low-emission electrochemical device that can be used in a variety of applications including automotive,distributed power generation and military.In recent years,PEMFC technology has made great progress in improving performance,reducing cost and increasing durability.Dead-Ended Anode(DEA)is an operating mode of PEMFC.In DEA mode,PEMFC has the advantages of high fuel utilization,simple structure,easy operation and wide application scenarios.Therefore,DEA mode is used as the preferred operation mode of PEMFC.This paper conducts an in-depth study of the PEMFC with DEA operating performance and investigates the mechanism of PEMFC performance degradation due to DEA mode and the influence of operating parameters on PEMFC local performance in order to improve the operating performance,fuel utilization efficiency and service life of the PEMFC with DEA.Firstly,the summary of the existing research on the working performance of PEMFC with DEA reveals that: the PEMFC with DEA,the accumulation of water and nitrogen on its anode side is the main reason for the degradation of PEMFC performance,and the change of operation parameters has an impact on the working performance of PEMFC with DEA.The analysis of the permeation mechanism of water and nitrogen in PEMFC with DEA reveals that:when PEMFC works in DEA mode,there is always a nitrogen concentration gradient on the cathode side.The nitrogen on the cathode side will permeate through the proton exchange membrane to the anode side and the permeation process cannot be avoided,but the water content of the proton exchange membrane has an effect on the permeation rate of nitrogen;the permeation of water on the cathode side to the anode side has three ways: electroosmotic drag,concentration counter-diffusion and pressure diffusion,and the change of operation parameters will have an effect on the permeation of water and nitrogen to the anode side.Secondly,the effects of different operating parameters on the performance and stable working time of PEMFC with DEA(with a single serpentine flow field structure)were investigated by fuel cell test bench experiments.The operating parameters were: operating temperature,cathode gas humidification,cathode gas stoichiometry ratio and anode operating pressure.It is found that the changes of operating temperature,cathode gas humidification,cathode gas stoichiometry ratio and anode working pressure all affect the operating performance and stable working time of PEMFC with DEA.Among them,the changes of operating temperature and cathode gas humidification have a large impact on the stable working time of PEMFC with DEA.Further,a three-dimensional and non-stationary simulation model of the PEMFC was established in this paper to study the effects of different operating parameters on the operating characteristics of the PEMFC with DEA and to reveal the mechanism of the changes in the operating performance of the PEMFC due to different operating parameters.The results show that the increase of operating temperature,decrease of cathode gas humidification and increase of anode pressure can improve the accumulation of water and nitrogen in the anode runner of PEMFC,and the increase of cathode gas stoichiometry ratio can alleviate the accumulation of water in the anode runner,but not the accumulation of nitrogen;the change of operating parameters has an effect on the water content of the proton exchange membrane.Finally,the effect of operating parameters on the local performance of PEMFC with DEA was investigated by the printed circuit board(PCB)partition measurement technique,and the mechanism of the change in the local performance of PEMFC due to the change in water and nitrogen distribution and accumulation on the anode side was revealed.The results show that the accumulation of water and nitrogen at the anode exit leads to a serious decrease in the local current density of the PEMFC and a significant change in the local voltage at the end of the anode.The change of the operating parameters alleviates the accumulation of water and nitrogen on the anode side,which in turn improves the local performance of the PEMFC with DEA,resulting in an improved operating performance of the PEMFC in DEA mode.
Keywords/Search Tags:PEMFC with dead-ended anode mode, Operating parameters, Working performance, Performance degradation
PDF Full Text Request
Related items