Polymer electrolyte membrane fuel cells (PEMFC) are able to efficiently generate high power densities, thereby making the technology potentially attractive for certain mobile and portable applications. Especially the possible application of PEMFC as a prime mover for automobiles has captured the imagination of many. Polymer electrolyte membrane fuel cells technology differentiates itself from other fuel cell technologies in that a solid phase polymer membrane is used as the cell separator/electrolyte. Because the cell separator is a polymer film and the cell operates at relatively low temperatures, issues such as sealing, assembly, and handling are less complex than most other fuel cells. The need to handle corrosive acids or bases is eliminated in this system. PEMFCs typically operate at low temperatures (60o to 80 oC), allowing for potentially faster start-up than higher temperature fuel cells. The Polymer electrolyte membrane fuel cells is seen as the main fuel cell candidate technology for light-duty transportation applications. While PEMFC are particularly suitable for operation on pure hydrogen, fuel processors have been developed that will allow the use of conventional fuels such as natural gas or gasoline. A unique implementation of the PEMFC allows the direct use of methanol without a fuel processor; it is the direct methanol fuel cell (DMFC). The DMFC is seen as the leading candidate technology for the application of fuel cells to cameras, notebook computers, and other portable electronic applications.
Typical cell components within a PEMFC stack include:
• the ion exchange membrane
• an electrically conductive porous backing layer
• an electro-catalyst (the electrodes) at the interface between the backing layer and the membrane
• cell interconnects and flowplates that deliver the fuel and oxidant to reactive sites via flow channels and electrically connect the cells.
PEMFC stacks are almost universally of the planar bipolar type. Typically, the electrodes are cast as thin films that are either transferred to the membrane or applied directly to the membrane. Alternatively, the catalyst-electrode layer may be deposited onto the backing layer, then bonded to the membrane.
Typical cell components within a PEMFC stack include:
• the ion exchange membrane
• an electrically conductive porous backing layer
• an electro-catalyst (the electrodes) at the interface between the backing layer and the membrane
• cell interconnects and flowplates that deliver the fuel and oxidant to reactive sites via flow channels and electrically connect the cells.
PEMFC stacks are almost universally of the planar bipolar type. Typically, the electrodes are cast as thin films that are either transferred to the membrane or applied directly to the membrane. Alternatively, the catalyst-electrode layer may be deposited onto the backing layer, then bonded to the membrane.
