PEMFC(Proton Exchange Membrane Fuel Cell)theoretically only emits water and is a clean energy without pollutants,which is also a trend for future energy development.In the standard state,the theoretical potential of the fuel cell is 1.23v,but the actual open-circuit voltage is only 0.95v~1.05v,mainly because the over-potential generated by hydrogen penetration reduces the open-circuit voltage.In previous studies,it was believed that hydrogen permeation also conforms to Faraday’s law.This paper avoids this hypothesis,introduces the concept of internal current,deduces the relationship between internal current and over-potential again,and draws the conclusion that the generation of internal current will affect the open circuit voltage of the battery.In this paper,the characteristics of the proton exchange membrane and the effect of defects in the proton exchange membrane on the battery were studied,and the battery performance was analyzed from the following aspects:thickness of the proton exchange membrane,pores in the proton exchange membrane,water film in the catalytic layer and the size of catalyst Pt load.The influence of proton exchange membrane thickness on the battery:when the membrane thickness decreases,the permeation flux of hydrogen increases.Under the same internal current,the over-potential needs to increase to balance the decrease of oxygen concentration.In terms of catalysis,the presence of water film and catalyst Pt load load in the catalytic layer will affect the number of hydrogen ions converted to hydrogen,thus affecting the permeation flux of hydrogen.It is concluded that the larger the Pt load load is,the better the battery is,and the presence of water film in the catalytic layer is better than the absence of water film.At the same time,the effects of different hole depths and hole densities on the battery were also studied under the condition that there were holes in the membrane.The hole density is less than 10,which has relatively little influence on the battery.For the l-type crack,the vertical influence is greater than the horizontal one.Moreover,the current density is within the range of 0~97 mA/cm~2,and the over-potential generated by hydrogen penetration has a great influence on the open circuit voltage of the battery.With the increase of current density,ohmic loss is the main factor that affects the open-circuit voltage.At the same time,when the proton exchange membrane has holes,the resistance of the battery increases and the conductivity decreases.The performance of the battery will also decline. |