Experimental And Numerical Study On Cathode Parameters Of Air Breathing Fuel Cell

Hydrogen has received extensive attention as a clean energy source.Fuel cells can directly convert hydrogen energy into electrical energy,avoiding the limitation of the Carnot cycle,and the efficiency can reach more than 60%.Compared with traditional proton exchange membrane fuel cells,air breathing fuel cell is small in size and can directly extract oxygen from the air.The cathode structure affects the efficiency of the battery to extract oxygen.In order to improve the performance of the fuel cell,this study decided to verify the thickness of the cathode tip,the shape of the the cathode flow field,the open ratio and the opening direction of the high-temperature self-breathing fuel cell from both experimental and simulation aspects..In view of the influence of cathode opening shape and cathode tip thickness on the fuel cell,three different cathode layers were processed and designed in this study.After processing and assembling the fuel cell,build an experimental platform to test the I-V curve of the battery when the shape of the cathode flow field is different.Since the performance of the phosphoric acid-treated proton exchange membrane is prone to decline,the accuracy is verified after each test.Comparing the I-V curve of the fuel cell under different conditions,the cathode flow field and the cathode end with the best performance were selected as the structure of the battery.In addition to the I-V curve of the fuel cell,the gas motion vector diagram of the air domain and the distribution of cathode oxygen are also important performance characteristics of the air breathing fuel cell.In order to be able to analyze the internal parameters of the battery,it is necessary to establish an electrochemical model of the fuel cell and verify the accuracy of the model.The CFD module in ANSYS software is used to simulate the operation of the fuel cell.In order to improve the performance of the fuel cell,it is necessary to determine the open ratio of the cathode flow field.Five kinds of aperture ratios of 45%,55%,65%,75%,and 85% are used for simulation analysis to determine the aperture ratio when the fuel cell performance is best.For the above five cases,the electrochemical model was established.After the simulation calculation,the post-processing was carried out.The physical parameters such as I-V curve,oxygen concentration and current density on the film were compared and analyzed to determine the cell opening ratio.This study has obtained the rule that the battery performance varies with the aperture ratio,which can provide guidance for engineering applications.In the case where the shape of the flow path,the open ratio,and the thickness of the cathode end are determined,it is also necessary to determine the orientation of the battery opening.In this study,the simulation method is used to compare the opening level and the opening vertically upwards.By comparing the current density with the air domain gas vector,the fuel cell opening level can be determined to be better,but the difference between the two is small.The research results have engineering practical significance.