| Proton Exchange Membrane Fuel Cell(PEMFC)is a power generation device that directly converts chemical energy into electrical energy.It is not restricted by the Carnot cycle and has high energy conversion efficiency.As long as there is enough hydrogen and oxygen,it can run continuously for a long time.Due to the advantages of high energy conversion efficiency,low noise,wide fuel sources,and no pollution(the reaction product is water),fuel cells have become an excellent power source,which can be used in backup power sources,automobiles,drones,submarines and military applications.,The application prospect is extremely wide.The water vapor transmission of hydrogen-oxygen proton exchange membrane fuel cells with dead-ended has an important impact on battery performance and durability.Through the visual experiment method to study the flow of water and gas in the fuel cell flow channel and the distribution of liquid water,the growth and movement process of the liquid water in the flow channel can be directly observed,which is helpful to understand its transmission characteristics,thereby optimizing the water and gas management inside the battery and improving Battery performance and durability.In this paper,a proton exchange membrane fuel cell with a transparent visualization window is designed.The visualization technology is used to study the water vapor transmission characteristics in the cathode flow channel of the fuel cell under different working conditions and the influence of different working conditions on the performance of the fuel cell.The specific conclusions are as follows:(1)Liquid water in the parallel direct current field first appears in the flow channel near the edge of the flow field and most of the liquid water is generated in the bank of the flow channel and gathers along the edge of the flow channel,while the liquid water in the serpentine flow field first appears in the flow channel.Road bends.Most of the liquid water generated in the hydrogen-oxygen fuel cell with dead-ended is concentrated at the entrance of the flow channel.The discharge of liquid water in the flow channel is an intermittent process.Only when the liquid droplets grow and merge to reach a critical volume,they will be discharged with the reaction gas.When the liquid water in the flow channel accumulates too much,it will fuse and form a plunger flow near the outlet of the flow channel.Runner.(2)At low current density,the rate of water production in the battery is slow,and the small amount of water produced can be discharged with the gas on its own,which has almost no effect on the performance of the battery;when operating under high density,it is not due to the presence of liquid water.It will affect the performance of the battery immediately,but when the liquid water accumulates to a certain extent,the performance of the battery may drop significantly.(3)Increasing the operating temperature can reduce the content of liquid water in the flow channel.Properly increasing the operating temperature can effectively improve the performance of the battery.However,when the operating temperature is too high,the membrane electrode will be dehydrated,which will actually reduce the battery performance.(4)With the increase of current density,the stable operation time of the battery is shorter,and the water accumulation in the flow channel is more serious;under the same working conditions,the battery can run smoothly for longer and better performance when using a wide straight field board.However,when using a serpentine flow field and a narrow straight field plate,the battery has a short stable running time and low performance.Therefore,under the same conditions,the more flow channels in the flow field plate and the wider the width,the better the battery performance. |
