Research On Matching Design Of Proton Exchange Membrane Fuel Cell Based On Joint Operation

The proton exchange membrane fuel cell is an energy conversion device with the advantages of high efficiency,cleanliness,low operating temperature and fast startstop response.In order to improve the mass transfer capacity and electrochemical reaction rate of the fuel cell,the performance optimization is realized.In this paper,based on numerical simulations,a non-uniform design is proposed,that is,a structural design that studies the gradient distribution of channel width and the porosity gradient distribution of porous electrode components(gas diffusion layer,microporous layer,and catalyst layer).The effects of non-uniform design on fuel cell performance were analyzed from the aspects of pressure distribution,distribution of reactants and products,electrochemical reaction rate and current density.In this paper,the non-uniform design of cathode and anode channel width and the non-uniform design of porosity of porous electrode components are separately analyzed.According to the flow channel area and the porous electrode component area,the entire flow channel and the porous electrode component are divided into three regions respectively,and the parameters of each region are set to realize the nonuniform design of the partitions.The results show that the gradual reduction of the cathode channel width(1.2mm,1.0mm,0.8mm)can improve the gas transmission performance of the channel and the ability to discharge liquid water in the gas diffusion layer.The gradual reduction of cathode porosity(The porosity of the gas diffusion layer is 0.7,0.6,0.5,the porosity of the microporous layer is 0.5,0.4,0.3,and the porosity of the catalyst layer is 0.4,0.3,0.2)is beneficial to promote the uniform distribution of membrane water.The structural design improves the electrochemical reaction rate and improves the utilization rate of the membrane electrode.Second,a synergistic design combining the non-uniform distribution of channel width and the non-uniform distribution of porosity in porous electrode components is proposed.Among them,the combined design in which the width of the cathode channel and the porosity of the porous electrode components are gradually reduced has the best performance improvement effect.On this basis,increasing the variation of the flow channel width can further improve the transport of reactant gases and the electrochemical reaction rate in the fuel cell.The structural design with a 0.3mm change in the channel width is the best design in this study,and the performance is improved by 2.77%.Finally,on the basis of the optimal non-uniform structure design,combined with the particle swarm optimization algorithm,a joint operation model of Matlab and Fluent is constructed.The effects of operating parameters such as working pressure,working temperature,relative humidity of cathode and anode,and stoichiometric ratio of cathode and anode on the performance of fuel cells were studied.Taking the average power density as the objective function value,the matching design of the operating parameters and the simulation model is realized.The optimal matching parameters obtained by joint operation are: working pressure 250000 Pa,working temperature333 K,anode relative humidity 85.60%,cathode relative humidity 50%,anode stoichiometric ratio 1.92,cathode stoichiometric ratio 3.The parameter matching design results are beneficial to explore the sensitivity of fuel cell performance to operating parameters,and also help guide the development of fuel cell control strategies in the research process.