Structural Safety Analysis Of Fuel Cell Stacks For Key Components Of Fuel Cell Vehicles

A fuel cell is an electrochemical power generation device that directly converts the chemical energy of hydrogen and oxygen into electrical energy,and the reaction product generates only water.In today’s energy crisis and increasing environmental pollution,fuel cells have received widespread attention as efficient,clean,and environmentally friendly energy equipment.Proton exchange membrane fuel cell(Proton Exchange Membrane Fuel Cell,PEMFC)has become one of the most studied and widely used fuel cell types due to the characteristics of rapid startup at room temperature,no electrolyte loss,high energy conversion efficiency and long life.,Has good application prospects in aerospace,mobile power,new energy vehicles and power stations.The PEMFC in practical application is mostly a large stack structure,and the contact pressure distribution of each component in the fuel cell assembly process has an important influence on the contact resistance.Too small assembly pressure leads to excessive contact resistance,resulting in poor sealing effect and reaction gas leakage.Excessive assembly pressure causes the component’s porosity to decrease and fail.In addition,the service environment of the fuel cell is relatively harsh,and it must withstand the test of severe temperature and mechanical conditions.On the one hand,because the stack is a stacked series structure,the thermal expansion coefficients of the materials of each component are different.When the ambient temperature changes,the thermal mismatch of the material layer causes the components to withstand the impact of thermal stress,which ultimately reduces the reliability of the fuel cell.On the other hand,the fuel cell is subjected to various forms of mechanical vibration and shock during the driving of the car,which generates large dynamic bending deformations that cause alternating stress,which ultimately leads to structural damage to the fuel cell.This paper takes PEMFC reactors as the main research object and uses numerical simulation methods to analyze the mechanical problems of the reactor assembly process and the thermal vibration performance of the reactor in detail.The main research contents are as follows:(1)Study the mechanical problems of the structure during the assembly of the reactor.The finite element software ABAQUS was used to carry out numerical simulation of the stack,and a three-dimensional stack model including end plates,bipolar plates,membrane electrodes and bolts was established.By applying different preload forces of bolts,the location of different bolts on the end plates,and Different stack stages are used to analyze the impact on the structure of the fuel cell stack and determine the optimal assembly form.(2)The effect of stack random vibration on the structure of fuel cell stack is studied.Random vibration signals are applied to the stack at three different speed levels of city congestion,urban unblocking and highway,to obtain the resonance frequency of the stack model and road surface excitation under different speed conditions and the stress of each component of the stack And displacement results.(3)The influence of thermal vibration on the structure of fuel cell stacks is studied.Applying unobstructed urban random vibration conditions to the stack and the effects on the stack structure under different temperature conditions of-10 °C,20 °C,and 40 °C,the resonance frequencies of the stack model and road surface excitation at different temperatures and Stress and displacement results of various components of the stack.