Proton Exchange Membrane Fuel Cell Flow Field Configuration: Modelling and Experimental Verification

Abstract

With climate change crisis the research community is forced to consider other alternatives for energy production. Therefore, renewable energy sources are today considered as the main replacement for fossil fuels in the future. Proton exchange membrane (PEM) fuel cells are gaining more attention as main power sources for powering various vehicles, such as cars, forklifts, golfcarts etc. [1, 2]. European Commission (EC) recognized the importance of the fuel cell and hydrogen technology and their inevitable role in reducing greenhouse gas emission by further encouraging hydrogen fuel cell integration in various vehicles in their hydrogen strategy for a climate-neutral Europe [3]. Beside water and heat management, one of the key elements of the PEM fuel cells are reactants flow field channels. Influence of flow direction, channel length and number of channels, cross-section shape, channel depth, channel to rib width ratio etc., on PEM fuel cell performances has been analysed in the literature. Improper design of flow field channels may lead to water stagnation and flooding and as a result poor fuel cell performance (polarization curve).The objective of this work is to find optimal flow field configuration – number of channels, channel width to rib ration and channel depth. To achieve this objective numerical modelling of PEMFC was done using Ansys 17.0, in which 3D geometry (via DesignModeler) was modelled and finite volumes mesh was generated. Developed model was simulated in Fluent, using computational fluid dynamic (CFD). Based on the simulation results, graphite bipolar plate with optimal channel design was machined, integrated into single PEM fuel cell unit with commercial MEA’s and tested. With the application of different geometrical parameters like the number of channels, channel width to rib ratio, channel depth, mass fraction of oxygen and heat transfer in the fuel cell can be optimized. Numerical modelling of PEMFC was done using Ansys 17.0, in which 3D geometry (via DesignModeler) was modelled and finite volumes mesh was generated. At last, PEMFC was simulated in Fluent, using computational fluid dynamic (CFD). After calibration of the based numerical model, simulations with improved flow field designs were created and compared to the based model. Flow field design which was configurated as 4 serpentines (counterflow mode) channels with the depth of 0.45 mm, resulted in the best improvement of performance comparing to the basic model. Obtained results were confirmed experimentally.References Tolj, I.; Lototskyy, M.V.; Davids, M.W.; Pasupathi, S.; Swart, G.; Pollet B.G. Fuel cell-battery hybrid powered light electric vehicle (golf cart): Influence of fuel cell on the driving performance. J. Hydrogen Energy 2013, 38, 10630-10639.Lototskyy, M.V.; Tolj, I. et al. Performance of electric forklift with low-temperature polymer exchange membrane fuel cell power module and metal hydride hydrogen storage extension tank. Power Sources 2016, 316, 239-250.Communication from the Commission to the European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions: A hydrogen strategy for a climate-neutral Europe, Brussels, 08.07.2020, https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:52020DC0301&from=EN