Air-cooled PEMFC Heat Dissipation Simulation Analysis And Improvement

Proton Exchange Membrane Fuel Cell(PEMFC)is a device that converts chemical energy directly into electrical energy,which has the advantages of high energy efficiency,environmental friendliness and high reliability.Therefore,accelerating the development of fuel cells is an important way to help China achieve carbon peak and carbon neutrality.At present,hydrothermal management is one of the key research objects of experts and scholars in the field of fuel cells,and it is also an important factor affecting the output performance of the cell.In view of the complexity of hydrothermal management inside fuel cells and the limitations of experimental research,this paper intends to investigate the thermal performance and output performance of PEMFC based on the PEMFC set total parameter model and distributed parameter model.Firstly,the parameter model of the PEMFC stack is established by the Nernst electrochemical equation and the law of energy conservation,and the correctness of the model is verified.Based on the simulation platform,the heat dissipation characteristics of the fuel cell reactor are studied by considering the heat dissipation factors such as forced convection,natural convection,thermal radiation and phase change heat absorption,and the effects of ambient temperature,air inlet flow and heat dissipation area on the output performance and temperature of the reactor are analyzed.Based on the results of the above analysis,a proposal to improve the heat dissipation performance of the stack by increasing the heat dissipation area(lengthening the length of the cathode runner)is proposed.Then,the three basic equations of fuel cell and the component conservation equation are used to model the distribution parameters of PEMFC single DC channel and verify the correctness of the model.The output performance of the fuel cell before and after the fuel cell model runner lengthening is compared using fluid simulation analysis software to show the transformation of the details related to the thermal characteristics such as current density,water content and temperature distribution inside the fuel cell,and to verify the feasibility of the above scheme at the microscopic level.The single-channel model with lengthened cathode runners is also used to analyze its effect on the thermal performance of the stack under different external loads,inlet temperatures and inlet flows.The results show that the average temperature inside the cell film of the doubled cathode runner decreases by more than 5°C compared with that before the lengthening,while maintaining the same output power;and there is a significant positive correlation between the lengthened cathode length and the improved thermal performance.This demonstrates that lengthening the cathode runner length can improve the heat dissipation performance and output performance of cathode open proton exchange membrane fuel cells.Finally,the experimental operation platform is built by a home-made 160 W stack,and the above simulation conclusions are extended from a single runner to a fuel cell stack for experimental verification.The experimental results show that the temperature(cathode outlet)of the cathode open proton exchange membrane fuel cell extended runner stack actually decreases by 3℃ compared to that of the unextended stack while maintaining the same output power of 160 W.It proves that lengthening the length of the cathode inlet runner can effectively increase the heat dissipation area of the cell,enhance the forced convection heat exchange effect,and improve the current density.In addition,the experiments show that increasing the spacing distance between cathode corrugated plates can also effectively improve the output performance of the stack.Finally,based on the experimental results,we propose to increase the auxiliary fan and enhance the forced convection heat dissipation of the cathode corrugated plates to enhance the output performance of the stack.By adjusting the parasitic power of the auxiliary fan,the net power of the stack is successfully increased by nearly 10 W at the same voltage,and this paper provides a theoretical basis and technical reserve for future research on thermal management and temperature distribution optimization.