Research On Thermal Distribution And Performance Of Proton Exchange Membrane Fuel Cells

In recent years,with the emission of automobile and the burning of large quantities of fossil fuels,the problem of environmental pollution has become more and more serious.So,it is urgent for finding a new type of low-pollution or non-pollution alternative energy to solve the current environmental pollution problem.Among them,proton exchange membrane fuel cell(PEMFC)has become the research focus for researchers because of its high energy density,low working temperature,non-pollution and other advantages.Therefore,based on the theoretical research of PEMFC,the following work has been done in this paper:(1)Based on the mass conservation equation,energy conservation equation,momentum conservation equation,component conservation equation and mass transfer equation of PEMFC,a numerical model of PEMFC with rectangular cross-section in straight channel is established and simulated.The results show that the simulation results agree with publicly published experimental results under the same operating parameters.It verified that the established numerical model is correct and it can be used for subsequent research.(2)The PEMFC model of trapezoidal and circular cross-section channel is established by using the method as mentioned above,and the same operating parameters are set up.The effects of different cross-section of channel on temperature distribution of PEMFC stack,temperature distribution in transverse electrode direction,temperature distribution with in the membrane and the output performance of cell are studied,so that the channel with minimum temperature difference in the membrane and relatively optimal output performance can be obtained.(3)On the basis of rectangular cross-section channel,three PEMFC models with different thickness of gas diffusion layer(GDL)and six PEMFC models with asymmetric thickness of GDL were established,respectively.The effects of nine models on the temperature distribution and output performance of the cell were studied,and the optimum thickness of symmetrical gas diffusion layer was obtained.Asymmetrical thickness of cathode and anode gas diffusion layer.(4)Based on the thickness of cathode and anode GDL of 0.19 mm and 0.29 mm respectively,the mathematical simulation model of PEMFC was established and thenumerical simulation was carried out.The effects of different air intake modes,air intake cycles and air flow velocity of cathode flow channel on the temperature distribution and output performance of PEMFC were studied.The results show that the alternating air intake mode can improve the maximum temperature position of the battery and properly mention electricity.The output performance of the battery can be significantly improved by alternating intake cycles.Increasing the air flow rate in the cathode passage can significantly reduce the temperature distribution in the battery and improve the output performance of the battery.However,when the air flow rate continues to increase,the output performance of the battery will decrease.