Fuel Cell Development
Development of Metal
Bipolar Plates for Proton Exchange Membrane (PEM) Power System
The Center for Fuel Cell Development
at the Institute for Research and Technology Transfer (IRTT) of the
Farmingdale State University of New York has successfully developed new
metal treated bipolar plates for PEM fuel cell power stacks. These power
stacks are much safer, very robust and more economical than the graphite
bipolar plates that are currently being developed nationwide. The metal
bipolar plates provide at least a 12% saving in hydrogen consumption in
comparison to graphite because of the lower ohmic resistance of metal.
Two patents have been filed to
protect IRTT’s exciting PEM fuel cell technology that includes a new
reactants flow field, robust power stack designs, and innovative
manufacturing techniques for efficient metal bipolar plates. A cost
effective Membrane Electrode Assembly (MEA) and utilizing dry reactants is
currently under development at the IRTT.
Various prototypes with power ranging
from 2 W to 8 kW have been fabricated, assembled and tested at the IRTT as
shown in Figure (1). The results of the lifetime testing conducted under
variable loading showed no indication of power degradation due to metal
corrosion for nearly 700 hours as depicted in Figure (2). This comparison
of graphite and metal bipolar plates clearly demonstrates the viability and
superiority of this novel technology.
Most bipolar plates are made of
graphite composites that are known to be relatively expensive, highly
brittle, and have low electric conductivity. Metal bipolar plates such as
aluminum and zinc are less expensive, more robust, highly conductive and
very easy to machine or die-cast. The lack of brittleness in metal bipolar
plates permits the exertion of the necessary tightening torque on the
stack’s tie rods to completely prevent reactant gas leakage to the outside
or around the Membrane Electrode Assembly (MEA) without any possibility of
cracking, unlike graphite.