Three-dimensional modeling of local dynamic characteristics in hydrogen fuel cells
During the operation of automotive fuel cells,dynamic loads may drastic changes in local physical quantities of the fuel cell,which in turn leads to a sharp decline in fuel cell performance and service life.To prevent the occurrence of the issues above,a thorough analysis of the local dynamic characteristics of the fuel cell under dynamic operating conditions is necessary.This study considers the 7-layer structural features of the membrane electrode assembly,and the energy transport facilitated by gas component diffusion and gas-liquid two-phase macroscopic convection,while also taking into account the localized energy changes resulting from phase transitions between gas-liquid-membrane phases.Building upon these considerations,a two-phase,non-isothermal,three-dimensional dynamic physical model of the fuel cell has been established.This model reveals the internal features of the fuel cell under dynamic loads,particularly focusing on the heat and mass transport,as well as the dynamic response characteristics of electrochemical reactions,in the catalytic layer region beneath the channel and rib of the bipolar plate along the flow channel.Furthermore,it elucidates the mechanisms underlying the formation of dynamic behaviors.The research findings indicate the presence of significant spatial-temporal thermal-mass response non-uniformities within the membrane electrode during the step change in current load,resulting in a decrease of approximately 20 mV in fuel cell output voltage,triggering additional power losses and heat generation,thereby causing further increasing in local temperature.
proton exchange membrane fuel celldynamic modelingtransient responseheat transferthree-dimensional model
万方数据
维普
