Katie S. Howe

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Dynamic Performance of Micro-Tubular Fuel Cells

• Katie S. Howe
• Centre for Hydrogen and Fuel Cell Research
• SOFC Research group
• www.fuelcells.bham.ac.uk
• www.hydrogen-wm-scratch.info

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Overview

• Starting Point
• Fuel cells
• Status of dynamic performance research
• Experimental Work
• Results
• Conclusions
• Next Steps

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Starting Point Fuel Cells

• Change electrochemical energy into useful
  electricity
• Like a battery, but not limited by how much fuel
  they can hold

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Starting Point Fuel Cells

• mSOFCs
• Tubular
• Better thermal shock resistance
• Fewer issues with sealing

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Starting Point Research Status

• Load-following capability is vital for most
  real-world applications
• In the literature
• Many papers on steady-state performance
• Some modelling work on dynamic behaviour 1-3
• ...but hardly any experimental results

1 Nehter, P., 2006, Journal of Power Sources,
157(1), pp. 325-334. 2 Ota, T., Koyama, M.,
Wen, C. J., Yamada, Y., and Takahashi, H., 2003,
Journal of Power Sources, 118(1-2), pp.
430-439. 3 Serincan, M. F., Pasaogullari, U.,
and Sammes, N. M., 2009, Journal of Power
Sources, 194(2), pp. 864-872.
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Starting Point Research Status

• Thermal transport time dominates dynamics4
• Readjustment time independent of step size5
• Undershooting of voltage when current rises5
• Size of undershoot related to step size

4 Bhattacharyya, D., and Rengaswamy, R., 2009,
"A Review of Solid Oxide Fuel Cell (SOFC) Dynamic
Models," Ind. Eng. Chem. Res., 48(13), pp.
6068-6086 5 Achenbach, E., 1995, "Response of a
solid oxide fuel cell to load change," Journal of
Power Sources, 57(1-2), pp. 105-109.
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Experimental Work - Method

• Single cells made to in-house techniques6
• Operated at 750?C
• Fuel 20ml/minute of pure hydrogen
• SolartronTM analytical 1400 Cell Test System
• Apply sets of square pulses of current
• Paper submitted7 with precise details

6 Dhir, A., 2008, "Improved Microtubular Solid
Oxide Fuel Cells," PhD Thesis, University of
Birmingham, 7 Howe, K. S. Kendall, K.,
Transient Performance of Micro-tubular Solid
Oxide Fuel Cells. Journal of Fuel Cell Science
and Technology 2010, .Paper Accepted awaiting
editorial changes
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Results

• Transient behaviour

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Results
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Conclusions

• Short re-adjustment time of lt0.5s is independent
  of step size
• Agreement with models in the literature
• No under-shooting of voltage on the change
• Suggests thermal transport is better than
  expected in these tubes

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Next Steps

• Combination of cells into small stacks
• Higher powers
• Dynamic performance testing of stacks
• Effects of changing to a hydrocarbon fuel on
  transient performance

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Acknowledgements

• With thanks to...
• My supervisors Kevin Kendall and Stephen Decent
• My sponsors RCUK and EADS Innovation Works

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Thank you!
Any questions?
www.fuelcells.bham.ac.uk