Research On The Effects Of Inlet Relative Humidity On The Performance Of Vehicle Fuel Cells

Proton exchange membrane fuel cell is a power generation device that uses hydrogen energy as an energy source.It has attracted the attention of scientific researchers because of its high power generation efficiency,high reliability,and environmentally friendly power generation.PEMFC’s water management has a great impact on fuel cell performance.Good water management can greatly improve fuel cell performance.Inlet relative humidity,as an important intake parameter in water management,has an important impact on fuel cell performance.This thesis conducts research from two aspects of experiment and simulation.First,based on the internal water transfer mechanism of the fuel cell,a relative humidity-current(RHC)model is proposed.The influence of related parameters such as the molar flow rate of anode water and the net migration coefficient on the current is deduced.Formulate the relative humidity-current calculation formula;secondly,give the calculation flow chart and calculation method of PEMFC,based on this simulation,including: establishing the geometric model of the fuel cell,and meshing it,and importing the mesh Perform calculations in the computational fluid dynamics software Fluent to obtain the internal component cloud diagram of the battery and the simulation data of various parameters;then,build a fuel cell test platform and give the working principle and test methods,experimental parameters and experiments of the fuel cell experimental system Step,carry out the test,and obtain the polarization curve of the test.Finally,the experimental results and simulation results were analyzed in detail,and the polarization curves of the Fluent model and the RHC model were analyzed.Discuss the water mass fraction and hydrogen mass in the PEMFC flow channel under different relative humidity based on the cloud diagram of the internal components of the battery.The change rule of the score and the water content of the membrane.The results show that when the operating temperature of PEMFC is 60℃ and the CRH is 100%,the ARH increases from 0 to 100%,and the performance of PEMFC gradually improves.When the ARH is 100%,the battery performance reaches the best.When the working temperature of the fuel cell is 60℃,the RHC model is closer to the experimental value compared with the Fluent model;the fuel cell working temperature is 60℃,and the increase in the CRH has a greater impact on the performance improvement of the PEMFC;Under relative humidity conditions,from the standpoint of the voltage consistency of the fuel cell stack,the overall performance of the single cell C1 is the best,while the single cell C10 performs the worst with the fastest voltage attenuation;when the fuel cell operating temperature is 60°C,the CRH is 100 %,as the ARH continues to increase,the water content in the proton exchange membrane also continues to rise.