Numerical Simulation Of The Contact Resistance In Proton Exchange Membrane Fuel Cell

The contact resistances lead to much power loss in proton exchange membrane fuelcell(PEMFC), which confine the application in automotive and aviation fields. Theprocess mechanism of contact resistances in PEMFC, as the basis of solving theseproblems, is investigated through numerical simulation in this dissertation. Themechanical, thermal and electrical contact behaviors during the running process ofPEMFC are analyzed, the rules of press volt and temperature distribution in everydomain during the running process of PEMFC by means of numerical simulation arediscovered, and the technics measures are put forward according to the results ofanalysis and the reasons for the problems of contact resistances in PEMFC. The initialized conditions are determined in the pre-assembly stage of PEMFC,which have great effect on the producing contact resistances. So, the finite elementmodel of pre-assembly contact analysis for PEMFC is built. Using this model, thecontact behaviors in pre-assembly stage of PEMFC are simulated, and the factors andrules affecting the contact behaviors are also discussed. In addition, the equation isbuilt on the basis of the relationship between contact press and contact resistances,which establish the foundation for numerical simulation of contact resistances inPEMFC. On the basis of pre-assembly contact analysis and electric contact analysis, an finiteelement model of mechanical, thermal and electrical coupled analysis for the runningprocess of PEMFC is developed in this dissertation. Through the secondarydevelopment to the universal finite element analysis software-ANSYS, it accomplishedthe process simulation of contact resistances in PEMFC in different conditions.Compared with former models, thermal-electrical analyses involve the effect ofdeformation and the variation of contact faces;and also involves the effect oftemperature, contact pressure. The calculated results show that this model may reflectthe actual condition of contact resistances in PEMFC. By the numerical simulation of contact resistances in PEMFC, the variation rules ofcontact faces, contact pressure, current density, contact resistance, body resistance andtemperature field, heat density, displacement during the running process of PEMFC arediscovered quantitatively. In the meanwhile, the simulation results explain theproducing mechanisms contact resistances in PEMFC. Contact resistances arecompared with the different bipolar plate.According to the analytical results in the heat-generation and volt distribution duringthe running process of contact resistances in PEMFC, some technics measures solvingcontact resistances in PEMFC are brought forward from the producing reasons forcontact resistances in PEMFC and the factors affecting them.