This application relates, primarily, to guiding structure for an inlet manifold in a fuel cell.
Fuel cells are becoming widely utilized to provide generation of power. In a standard fuel cell, an inlet manifold directs a fuel, such as hydrogen, from a pipe into a generally planar manifold. A common configuration has the manifold positioned on one side of a cell stack, and an outlet manifold is positioned on an opposed side of a cell stack. Another configuration has the inlet and outlet manifold on the same side each covering a proportion of that side while the opposite side is a fuel turn manifold which covers the full side.
The fuel enters through the inlet pipe at a relatively high velocity, and then expands into the enlarged area of the inlet manifold. The high velocity fuel stream presents a challenge to evening spread the fuel across the face of the cell stack in the manifold. An even distribution of fuel is important to increase fuel cell operational life and to provide rapid start up. An uneven distribution, or maldistribution, of fuel will locally starve portions of the fuel cell. This starvation will create permanent areas of damage to the anode and cathode cells.
Previous attempts that have been utilized is the provision of a plurality of guiding passages such that the fuel is split into a number of separate channels, and then distributed across the face of the cell stack.
These approaches have been unduly complex, and have not always adequately addressed the problem.
An example fuel cell includes an inlet manifold that communicates with an inlet pipe. The inlet pipe enters the inlet manifold at a port. A baffle is positioned about the port. The baffle captures and directs fuel away from a side of the inlet manifold that will face a cell stack. A fuel cell incorporating such an inlet manifold is also claimed.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
A fuel cell 20 is illustrated in
As shown in
Also the space between the baffle side plates 36 and 38 and the curved outer wall 46 is large to allow water droplets to fall downward and not collect or create puddles. This feature provides a benefit in cold weather operation. The space is sufficient such that when ice forms it is less likely to bridge the baffle and side wall gap. As such, entrained fluid will provide little concern with this arrangement.
The nominal size of a water droplet is 2.3 mm in diameter. The gap of the flow passages could be 5.0 mm or larger to prevent water droplet bridging. If so, ice will likely not form a barrier and block the fluid flow channels.
If the fuel cell inlet piping 30 is positioned vertically along with the baffle 37 and contoured side walls 44 and 46 then the functioning will remain as described previously.
As can be appreciated, the baffle directs the fuel in a direction away from the cell stack and in opposed lateral directions relative to a flow direction leaving the inlet pipe.
As mentioned above, the inlet pipe 30 can be at any other position relative to the remainder of the fuel cell. Also, while a particular arrangement of inlet manifold, outlet manifold, and fuel cell stack is illustrated in
Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US08/83073 | 11/11/2008 | WO | 00 | 3/22/2011 |