Evaluation of the Effects of Microporous Layer Characteristics and Assembly Parameters on the Performance and Durability of a Planar PEM Fuel Cell

In recent years a significant portion of proton exchange membrane fuel cell (PEMFC) work has been focused on understanding and optimizing the functions of the microporous layer (MPL). Researchers have found that including this layer, composed of carbon black and TeflonTM (PTFE), between the gas diffusion layer (GDL) and catalyst layer (CL) of PEMFCs improves performance. The major benefit of the MPL in conventional fuel cells is that it improves water management and reduces contact resistances between cell layers. Although the functions of the MPL in conventional PEMFCs are well understood, the essential functions and optimal formulation of the layer in planar PEMFCs which operate without stack compression, are for the most part unknown. This work determines the essential functions and optimal composition, loading and sintering pressure of the MPL in a planar fuel cell design called a Ribbon Fuel Cell. Adhesion as well as performance data were gathered to determine the essential functions and formulation of the MPL which leads to high performance and durability in Ribbon Fuel Cells. Statistical models were created based on performance data of cells constructed with various MPLs; and a MPL composed of 45 wt% PTFE, loaded at 3.5 mg/cm° and sintered between 20 and 40 psi was found to exhibit optimal performance and durability. The reason why such a high PTFE content yields optimal results is because it strengthens the MPL, allowing it to successfully join various cell layers together, a function that is essential in Ribbon Cells which operate without external stack compression.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2009

Author dc:creator

• Burand, Patrick Hiroshi

Chair dc:contributor.committeechair

• Ellis, Michael W.

Committee members dc:contributor.committeemember

• Dillard, David A.
• Nelson, Douglas J.

• Planar Fuel Cell
• Ribbon Fuel Cell
• Microporous Layer
• PEMFC

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Dc Identifier Other

etd-11102009-171444

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/76885