Hydrothermal Management State Diagnosis Of PEMFC And Optimal Power Point Based On Internal Resistance Characteristics

The development of new energy technologies and the large-scale use of clean energy to achieve a low-carbon economy has become the latest trend in the development of energy technology in the world today.Hydrogen energy,as a new energy source with high efficiency,cleanness and pollution-free,has received wide attention from researchers all over the world.Fuel cell power generation technology is one of the important application directions of hydrogen energy utilization and development.It has the characteristics of clean and pollution-free,high power density and environmental friendliness,and has good application prospects.However,internal hydrothermal state management is of great significance for improving the output performance of fuel cell stacks.In this paper,a theoretical study is carried out on the hydrothermal management inside the fuel cell stacks.Through the mechanism modeling,the internal resistance and operating conditions of the fuel cell stacks are completed,and the decoupling relationship between the temperature and humidity of the stack is derived from the water content of the stack,and the total internal resistance of the stack is the minimum.Excellent standard,complete the optimal temperature and humidity values of the stack at different current densities,and derive the relationship between AC impedance and DC impedance for verification.Secondly,based on the principle of electrochemical impedance spectroscopy,combined with the equivalent circuit model,a method for calculating the state of hydrothermal management of electric reactor based on frequency secant angle calculation is proposed.Through simulation and experimental research,the results show that the frequency secant angle calculation result can A good description of the state of the hydrothermal management in the reactor,and the impact of changes in operating conditions on the output performance of the stack;Finally,considering the actual use of the reactor,the concept of optimal power point is proposed.Through theoretical analysis and derivation,the corresponding current value of the minimum total internal resistance of the reactor under the fixed operating conditions can be obtained,which can be calculated.The optimal power point of the fuel cell stacks has a good application prospect.