Research On Hybrid Energy Management Method Of Proton Exchange Membrane Fuel Cell Based On Life Degradation

Proton Exchange Membrane Fuel Cell(PEMFC)is an energy conversion device that works at lower temperatures and can directly convert the chemical energy of hydrogen into electrical energy.PEMFC has the advantages of high conversion efficiency,low operating temperature,low operating noise,and pollution-free emissions.It is a high-quality solution for future stationary power generation and vehicle energy.However,life decay is one of the main reasons limiting its application.The changing load and improper operation in the application scenario have a great impact on the life of the PEMFC.Therefore,it is very important to theoretically analyze the causes of degradation and delay aging through control methods.This thesis analyzes the platinum degradation mechanism and establishes an degradation model and life index.Using the energy management method of the hybrid energy system,the multi-objective problem of low fuel consumption and reducing life decay is studied.This thesis first analyzed the mechanism of the dissolution and deposition process of platinum in the PEMFC catalytic layer,and established a mechanism model based on the electrochemically active surface area(ECSA).The model used Euler’s method to calculate the occurrence of platinum in the catalytic layer.The chemical reaction rate on the surface of the particle was used to obtain the change of the platinum particle size to deduce the change process of ECSA.Then the square wave test voltage was analyzed based on the model,and then a PEMFC degradation empirical model suitable for engineering and an degradation-oriented strategy were proposed.Then based on the principle of each component and conservation equations,a dynamic model of each part of the system was established,including the fuel cell stack and its air supply system,lithium battery,etc..In addition,the relationship between the performance of each component of the system and the control quantity was analyzed.At last,this thesis proposed a rule-based energy management method and an energy management optimal control method aiming at the lowest fuel and life decay,and compared the results of different energy management methods under the same working conditions.The influence of life index weight was analyzed in detail,and the results showed that the proposed algorithm had the advantages of extending the service life of PEMFC and taking into account low fuel consumption.