Study On The Impact Of Structural Parameters Of Single Component On The Reaction Characteristics Of Fuel Cell At High Temperature

In recent years,energy and environment become the two hot topics of today's society because of dire shortage of energy and increasingly serious environment deterioration,tackling with these two problems is fundamental for human survival and development,in order to address this problem,people relentlessly develop and research on the new energy,among them,Proton Exchange Membrane Fuel Cell?PEMFC?has become one of the most potential for development of new energy for its clean,effective and wide range of use.At the present stage,the research on PEMFC mainly is to develop property of new materials,power generation performance,such as current density distribution,voltage change,durability,etc.,while the research on its internal temperature distribution under high temperature conditions?80??100??is still in the stage of development,and research on high temperature conditions can improve the whole performance of fuel cells.Under high temperature condition,the structural parameters of single component influence a lot on the temperature distribution uniformity and power generation performance of single fuel cell.Therefore,the research core of this paper is the temperature distribution inside the fuel cell,especially the temperature distribution on the reaction surface.This paper adopts the method of experiment to study the influence of the temperature distribution reaction surface of fuel cell on its power generation performance and service life,use the thermal imager to measure the temperature on the back of the bipolar plate,and calculates temperature distribution of reaction surface through the one-dimensional heat transfer model,and evaluates and analyzes the comparison of the temperature distribution and power generation performance obtained from experiment.Among which,the characteristic of reaction surface were assessed by the difference T_react-T_ini between the temperature of reaction surface(T_react)and the initial temperature of gas supply(T_ini).The operating variables in this paper are initial conditions of gas supply?stoichiometric ratio of gas supply,gas supply,relative humidity of gas supply,initial temperature of gas supply?and structural parameters of single components?thickness of proton exchange membrane?PEM?and thickness of gas diffusion layer?GDL??.The main contents and conclusions of research are as follows:?1?Analysis on influence of gas stoichiometric ratio:as for the gas stoichiometric ratio,we select 1.5,2.0 and 3.0 under different parameter variables as the object of research,and the result shows that the stoichiometric ratio of gas supply has little influence on the temperature distribution and was not affected by the change of relative humidity and type of monomer component.?2?Analysis on the influence of gas supply of relative humidity:on the research of gas supply of relative humidity,A40%RH C80%RH,A80%RHC40%RH and A80%RH C80%RH under different parameter variables were selected as the objects of research The results shows that relative humidity of air supply has no influence on monomer component when it is Nafion211 and TGP-H-030,but has great influence on it when is Nafion115 and TGP-H-060,and the power generation performance is the best when the relative humidity is A80%RH C80%RH.?3?Analysis on the influence of initial temperature of gas supply:to experiment the initial temperature of gas supply,we select 80?,90?and 100?under different parameter variables.The results show that T_react-T_ini lowers with the rise of initial temperature.However,when the initial temperature of gas supply is 100?,due to the increase of water evaporation rate in PEM membra ne and the damage of its microstructure,proton conductivity is weakened,so the electrical performance at this temperature is greatly reduced.?4?Analysis on the influence of thickness of PEM:we select Nafion 115,Nafion211 and Nafion 212 under different parameter variables as the objects of research.Results shows that the when PEM type is 127?m Nafion 115,the water absorption rate of PEM is high and the water capacity is large,which leads to the enhancement of proton conductivity of PEM and the distribution uniformity of T_react-T_ini in the reaction process,and the increase of power generation performance of fuel cell.However,when the PEM types were 25?m Nafion 211 and 51?m Nafion 212,the water absorption rate of PEM was low and the water capacity was small,so the proton conductivity and T_react-T_inidistribution uniformity were weakened,and the power generation performance of fuel cell was reduced.?5?Analysis on the thickness of GDL thickness:we select TGP-H-060 and TGP-H-030 under different parameter variables as the objects of research.The results show that when the GDL type of TGP-H-030 is 110?m,the water drainage is good,which can prevent the retention of generated water,make the electrochemical reaction from the inlet to the outlet evenly during the reaction process,and lead to the increase of fuel cell power generation performance.Therefore,it can be concluded that reducing the GDL thickness can improve the power generation performance of fuel cells.