High-Temperature Polymer Electrolyte Fuel Cells (HT-PEFC) Institute of Energy and Climate Research - Fuel Cells (IEK-3)

Co-operation

The HT-PEFC research, development and demonstration activities at the IEK-3 are partly being performed in co-operation with German industries and research centers for which funding is received from the industrial partners and the German Government.

Modeling and Simulation

R&D activities:

• Analyticalandnumericalmodelingofcellsandstacks

• Lattice-Boltzmannsimulationofgastransportinporousmedia

• ComputationalFluidDynamics(CFD)simulationsof HT-PEFCflowfields,cellsandstacks

Aims:

The overall goal of modeling is to map the characteristics of the fuel cell to appropriate equations and computer models. The following problems are addressed:

• Understandingofphysical-chemicalbasics(heat,mass and charge transport)

• Optimizedpowerandefficiency

• Optimizedstackdesign(currentdensityandtemperaturedistribution)

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Current density distribution inside a HT-PEFC short stack (200 cm² active cell area)

Contacts

Prof. Dr. rer. nat. W. LehnertHigh-temperature Polymer Electrolyte Fuel CellsInstitute of Energy and Climate Research – Fuel Cells (IEK-3)

Tel.: +49 (0)2461 61-3915 Fax: +49 (0)2461 61-6695 Email: w.lehnert@fz-juelich.de

Prof. Dr.-Ing. D. Stolten DirectoroftheIEK-3

Tel.: +49 (0)2461 61-3076 Fax: +49 (0)2461 61-3385 Email: d.stolten@fz-juelich.de

URL: www.fz-juelich.de www.fuelcells.de

ForschungszentrumJülichGmbH,52425Jülich,GermanyInstitute of Energy and Climate Research (IEK)

Simulation

Experiment

Testing capabilities

R&D activities:

• Characterizationofsinglecellsandstacks

– powerrange:somewatts(singlecells)upto5kW(stacks)

– temperature range: up to 200 °C– humidification: up to dew point 70 °C– gas composition, anode: H2, different reformates,

cathode:O2, air– specific testing methods: current density and tempera-

turedistribution,EIS,polarizationcurves,pressuredrop

• Long-termtestingatautomatedtestrigs

• Developmentoftestprotocols

Aims:

• PerformancemapofHT-PEFCstacks

• Understandingofdegradationmechanisms

• Validationoftheoreticalcellandstackmodels

• Optimizationofstackcomponents

MEA preparation

R&D activities:

AtIEK-3wedevelopMembraneElectrodeEssemblies(MEAs)basedonpolybenzimidazole-typemembranes(ABPBI). For appropriate proton conductivity they are doped with phosphoricacid.OperationtakesplaceinHT-PEFCsystemsoperated at temperatures of about 160 °C with hydrogen and reformate as fuels and air as oxidant.

Aims:

• Reductionoftheactivationpolarizationbytheuseof different catalyst materials

• Minimizationoftheconcentrationpolarizationbyreductionofcatalystlayerthicknessandvariationofthegasdiffusionlayer material

• Estimationofthephosphoricaciddistributionduringfuel cell performance and exert direct influence on this distribution

Stack development

R&D activities:

TheR&DactivitiesarefocusedonthedevelopmentandoptimizationofstacksforAPUsystemsbasedonmiddledistillateslikediesel,jetfuelorbiofuels.

Aims:

• Robustandefficientstackoperation

• Highvolumetricandgravimetricpowerdensity

• Easeofmanufacturingandstandardizationofcomponents(e.g. seals, bipolar plates)

• DurabilityandcyclingabilityunderAPUconditions

The picture shows one of our automated single cell test rigs, including supply lines, controllers and data acquisition

The picture shows a standard 16.65 cm² single cell with the endplate, the flow field with gasket, and the membrane elec-trode assembly.

The picture shows a modular designed 5 kW stack developed for the operation with kerosene based reformate. The stack consists of 6 modules with 12 cells (active cell area 320 cm²) each. Heating up and cooling is assisted by a thermal oil loop.