Study On Amphiphilic Pores And Wetting Characteristics Of Gas Diffusion Layer Of Proton Exchange Membrane Fuel Cell

Owing to low operating temperature,high current density,high energy conversion efficiency and clean,Proton exchange membrane fuel cells(PEMFC)has an extensive foreground in the new energy field of automotive,aerospace and backup power supplies.Water management is one of the difficulties that constrains the adhibition of PEMFC,the content of water should be moderate,and water transmission should be in dynamic balance.As a water transport medium,gas diffusion layer provides water transmission channels,which can guide water from the surface of the catalyst layer into the electrode plate flow channels,then out of PEMFC.This paper makes an improvement of the structure of gas diffusion layer,and puts forward a new gas diffusion layer structure where amphiphilic pores arrange regularly.The amphiphilic pores are not only hydrophilic,but also hydrophobic.The molecular dynamics method is used to research the wetting properties of droplet in the amphiphilic pores from a molecular perspective,including infiltration and transmission process.Following are the main research contents and results:1.After simulating infiltration process of droplet in hydrophilic,hydrophobic and amphiphilic pores,we analyze the effect of properties of amphiphilic pores on infiltration of droplet,and obtain the effect of the properties of amphiphilic pores on infiltration of droplet.Amphiphilic pores have the best infiltration process,which has the characteristics of low resistance,quick speed and small infiltration acreage.When the hydrophobicity of amphiphilic pores is constant,with the hydrophilicity increasing,droplet wetting is more easy,and quicker,but wetting acreage is larger.When the hydrophilicity of the amphiphilic pores is constant,with the hydrophobicity increasing,droplet wetting have more greater resistance,and infiltration speed is slower,but infiltration acreage is smaller.Therefore,relationship among the starting time of infiltration,the infiltration speed and the infiltration area should be taken into account when choosing the performance parameters of the amphiphilic pores.2.By simulating the transmission process of droplet in the pores with different covering properties,researching the effect of the covering properties on droplet transmission,we obtain the effect of the covering properties of the amphiphilic pores on droplet transmission.The droplet transmission cross section in amphiphilic pores is U-shaped.Compared with hydrophilic and hydrophobic pores,amphiphilic pores have higher transmission speed.When the hydrophobicity of amphiphilic pores is constant,with hydrophilicity increasing,droplet transmission speed goes up,which means transmission process is positive.The effect of hydrophobicity on droplet transmission speed is not obvious When the hydrophilicity of the amphiphilic pores is constant.3.By simulating the process of water from CL to GDL,the effect of properties of microporous layer and base layer on water transmission is researched,and we obtain the effect of properties of GDL on water transmission.With microporous layer become more hydrophilic transfer rate become lower.When base layer has amphiphilic pores,with amphiphilic pores become stronger,water transmission rate is higher,this means that it is more conducive to the water transmission.