Lightweight Titanium Metal Bipolar Plates for PEM Fuel Cells

Abstract:

Bipolar plates (BPPs) serve multiple roles in polymer electrolyte membrane fuel cells (PEMFCs). When assembled in a stack, they provide the structural backbone of the stack, plus serial electronic connections. They also provide gas (air and fuel) and coolant distribution pathways. Traditionally, bipolar plates have been made of carbon, but these are being replaced in favor of metal bipolar plates made of stamped foils. The Naval Research Laboratory has explored making titanium metal BPPs using 3D printing methods (direct metal laser sintering – DMLS) and superplastic forming, and then using a gold/TiO₂ surface layer for corrosion resistance. The 3D printed plates are made as one piece with the coolant flow internal to the resulting 2-mm thick structure. Their surface roughness requires smoothing prior to coating to increase their cell-to-cell conductivity. We found that 3D printed cells with 22 and 66 cm² active areas are slightly warped, preventing the robust sealing of the stacks. The formed plates are made in separate pieces and then joined. Despite the high temperatures required for superplastic forming, the resulting plates are thin and lightweight, making them highly attractive for lightweight compact PEMFC stacks.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 613-618
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.613
• Online since: November 2016
• Authors: Karen Swider Lyons*, Benjamin D. Gould
• Keywords: 3D Printing, Additive Manufacturing, Bipolar Plate, BPP, Direct Metal Laser Sintering, DMLS, Fuel Cell, PEMFC, Superplastic Forming, Titanium

References

[1] T. Yoshida, K. Kojima, Toyota MIRAI fuel cell vehicle and progress toward a future hydrogen society, Electrochem. Soc. Interface, Summer (2015) 45-49.

DOI: 10.1149/2.f03152if

[2] K. Kojima, K. Fukazawa, Current Status and Future Outlook of Fuel Cell Vehicle Development in Toyota, ECS Trans., 69.

DOI: 10.1149/06917.0213ecst

[17] (2015) 213-219.

[3] B.D. Gould, J.A. Rodgers, M. Schuette, K. Bethune, S. Louis, R. Rocheleau, K.E. SwiderLyons, Performance and limitations of 3D-printed bipolar plates in fuel cells, ECS J. Solid State Sci. Tech., 4 (2015) P3063-P3068.

DOI: 10.1149/2.0091504jss

[4] B.D. Gould, R. Ramamurti, C.R. Osland, K.E. Swider-Lyons, Assessing fuel-cell coolant flow fields with numerical models and infrared thermography, Int. J. Hydrogen Ener., 39 (2014) 14061- 14070.

DOI: 10.1016/j.ijhydene.2014.07.018

[5] C. Wang, Y. Tao, Coatings for Robust Metal Bipolar Plates, ECS Trans., 64.

[3] (2014) 909- 915.

[6] C.J. Netwall, B.D. Gould, J.A. Rodgers, N.J. Nasello, K.E. Swider-Lyons, Decreasing contact resistance in proton-exchange membrane fuel cells with metal bipolar plates, J. Power Sources, 227 (2013) 137-144.

DOI: 10.1016/j.jpowsour.2012.11.012

[7] T.L. Smith, A.D. Santamaria, J.W. Park, K. Yamazaki, Alloy selection and die design for stamped Proton Exchange Membrane Fuel Cell (PEMFC) bipolar plates, Procedia CIRP 14 (2014) 275-280.

DOI: 10.1016/j.procir.2014.03.078

[8] J.A. Rock, H. Schlag, K.R. Griffith, Stamped fuel cell bipolar plate, US 7459227 B2, Dec 2, (2008).

[9] G.C. Cornfield, R.H. Johnson, The forming of superplastic sheet metal, Int. J. Mechan. Sci., 12 (1970) 479-489.

[10] C.H. Hamilton, F.B. Koeller, R.S. Raymond, M. Goldberg, Controlled environment superplastic forming of metals, US Patent: US3934441 A, Jan 27, (1976).