PEMFC Channel Pattern Control And Guidance Based On New Fish-scale Bionic 3D Flow Channel

PEMFC(Proton exchange membrane fuel cell)have the advantages of low mass,high energy density,low noise,cleanliness.They can directly convert stored hydrogen into electricity through electrochemical reactions.It is of great significance to the improvement of the energy structure and governance environment,and has been applied to the civilian and military fields.After years of development of fuel cell technology in China,some achievements have been made,but research on the performance and life of PEMFC is still an international key technology to be broken.The water management of fuel cell is a complex issues involving physical and chemical processes.Too much or too little liquid water in the battery will affect the performance and life of the PEMFC.Especially when the battery is in the state of high potential,it is prone to "flooding" abnormal working conditions.Failure to expel the liquid water in the fuel cell in time will cause the active sites of the CL(Catalytic Layer)to be covered,and the mass transfer of the reaction gas will be uneven,which will reduce the performance of the battery and reduce its life.In order to solve the "flooding" of fuel cells and promote drainage,a PEMFC flow channel model with fish-scale bionic deflector was proposed in this paper.Aiming at the bionic flow channel first proposed in the paper,the VOF(Volume of Fluid)of ANSYS was used to simulate the water transport process in the flow channel.Through fluid dynamics simulation research,the following conclusions were reached:(1)The fish-scale bionic deflector changed the discharge mode of liquid water,so that the droplet jumped off the GDL(Gas Diffusion Layer)surface smoothly,which could improve the drainage efficiency of the flow channel and reduce "flooding " risk.(2)The shape and discharge mode of liquid water on the surfaces with different wetting characteristics are different.The liquid droplet can be completely discharged from the flow channel on the hydrophobic surface,but on the hydrophilic surface,the liquid water takes the form of a liquid film,and when it leaves the bionic deflector,it will be broken into small liquid droplets discharge channel.(3)When the inclined angleof the deflector selected is 15 °,the shape of the droplet is most conducive to the discharge of the droplet.In terms of time,the drainage time of the 3D bionic channel is shorter than that of the traditional channel.Liquid water can be smoothly detached from the GDL surface through the deflector,which can effectively let out the porous mass transfer channel of GDL,which can not only improve the drainage efficiency of PEMFC,but also improve the mass transfer efficiency of reaction gas.The results show that the fish-scale bionic deflector of the 3D channel provides a reference for the hydrothermal management technology of PEMFC.