| With the implementation of the 14 th Five-Year Power plan,China has put forward the "Dual Carbon Strategy",striving to achieve "Carbon Peak" before 2030 and "Carbon Neutral" before 2060,and the use of Proton Exchange Membrane Fuel Cell(PEMFC)can help reduce carbon emissions.The homogeneity of PEMFC stack performance is an essential problem in the study of stack reliability and service life.It is a comprehensive problem involving electrochemistry,heat transfer,mechanics and other multidisciplinary fields.From the perspective of mechanics analysis,the distribution of clamping load leads to uneven distribution of stress of internal components,including Gas Diffusion Layer(GDL)as a key component of heat transfer and mass transfer,the surface of the contact pressure is too large will result in the decrease of porosity,thus affecting the reaction gas transmission efficiency,and the contact pressure is too small will lead to increas ohmic loss because of the overlarge local contact resistance.Therefore,how to design clamping parameters to improve the uniformity and consistency of GDL contact pressure distribution in each layer of the stack has very important research significance.In this paper,from the perspective of clamping mechanics,on the basis of retaining the complex structure of the internal components of the stack,the finite element simulation modeling of the PEMFC stack is carried out,and the contact pressure value of GDL is calculated,and the average value and coefficient of variation are used as the evaluation magnitude of the value and uniformity of the contact pressure,respectively.The influence of clamping load and endplate thickness on GDL contact pressure distribution in stack was analyzed.Then,the average value and coefficient of variation of GDL contact pressure on each layer in 80 cell-stack are quantitatively compared to analyze their variation.In addition,the variation characteristics of the contact pressure distribution of GDL with the increasing number of cells is discussed.Support Vector Regression was used to establish a data-driven surrogate model with clamping load and endplate thickness as inputs and GDL average contact pressure and variation coefficient as outputs to predict GDL contact pressure.The model was used as the fitness function of the optimization algorithm,and the clamping parameters were optimized by the gray Wolf optimization algorithm.The contact pressure value after optimization was close to 1.1 MPa,and the distribution uniformity was improved by 66.67 %.A new method to improve the efficiency of solving the mechanical response of large stack is explored.The modal frequencies and modes of single cell and stack were solved by finite element method,and the free modal tests of single cell were carried out by hammer method to calibrate the modal parameters of dynamic simulation model.Then,the power spectral density of the three-way acceleration signal collected by FCV was used as the boundary condition of random vibration simulation analysis,and the dynamic response characteristics of acceleration,displacement,Von Mises stress of components in the stack were calculated.It provides support for subsequent component fatigue failure analysis and transient dynamics research. |
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