Thermodynamic Performance Analysis And Multi-objective Optimization Of Fuel Cell System

As an efficient and clean energy conversion device,fuel cells are favored by humans in today's society where energy is scarce and environmental pollution is serious.And with the development of information technology,the proton exchange membrane fuel cell(PEMFC)power system can be used as the preferred power equipment in the future due to its long life time,small size,and good maneuverability.However,due to its high cost and low power density,the PEMFC has been greatly restrained from its large-scale application.For further explore the influence of different operating parameters and environment on the output performance of the PEMFC,and analyzing the distribution of optimal operating parameters of the fuel cell.The specific research contents and conclusions of this article are as follows:1.A simulation model of the hydrogen-air,hydrogen-oxygen proton exchange membrane fuel cell system was established,and the influence of different working conditions on the output performance of fuel cell system was analyzed and compared.The results show that increasing the anode inlet pressure and the relative humidity of the inlet gas will improve the overall output performance of the fuel cell.Increasing the current density can also increase the output power of the system.When the current density is about 900 mA/cm~2,the output power of the system reaches a maximum value.Through analysis,we can see that in order to ensure the output characteristics of the system,the selection of fuel cell current density should not be too small,but it should not exceed 950 mA/cm~2.Under the same working conditions,the hydrogen-oxygen fuel cell has significantly improved of the system output power and the system output power efficiency compared to the hydrogen-air fuel cell.2.Based on the model of the proton exchange membrane fuel cell that has been built,the effect of altitude on the fuel cell performance was analyzed.The results show that with the increase of the flying height,the output voltage,electric power and system efficiency of the system are gradually reduced.Larger operating current results in greater attenuation of the electrical power and efficiency,and as the height increases,the optimal operating current of the system gradually decreases.At a current density of 1000 mA/cm~2,when the height rises to 5 km,the system output power decreases by 14.9%.At the same altitude,the PEMFC system maintains relatively suitable current density and high hydrogen inlet pressure can effectively improve the output performance of the entire power system.3.Multi-objective optimization of the system using multi-objective optimization algorithm to obtain the optimal operating parameter set of the fuel cell,and provides a theoretical basis for the optimization of fuel cell performance.According to the different weights of the objective function,the optimization results are as follows:the current density is uniformly distributed between 100-1000m A/cm~2,the working temperature is close to 348K,the hydrogen inlet pressure is between 2.8atm-3atm,and the air inlet pressure is between 1.2atm-1.6 atm,the relative intake humidity is mostly distributed at 100%.This paper provides technical and theoretical support for the industrial application of fuel cells through the simulation and optimization analysis of fuel cell systems.