Patent Application
20080070092
Although described herein as a single fuel cell assembly, it is appreciated that several assemblies can be combined to form a fuel cell stack without exceeding the scope of the invention.
The cathode plate 12 is formed of a metallic material suitable for use in a fuel cell environment. Illustratively, the cathode plate 12 may be formed of various metallic materials including, but not limited to, graphite, aluminum or other metals. The cathode plate 12 is configured to provide strength and durability to the fuel cell assembly 10 to reduce the risk of damage caused during handling and/or shipping. Other materials known to those skilled in the art, or may become known in the future, may be suitable for use in forming the cathode plate 12 which provide similar levels of strength and durability as metal.
The anode plate 14 is formed of a composite material that is configured to provide corrosion resistance to the harsh anode environment which can be highly acidic. Also, forming the anode plate 14 from a composite material helps to reduce the oxidative damage caused to the fuel call assembly 10 from the electrochemical environment. Preferably, the anode plate 14 is formed of a non-metallic material such as, for example, BMC940 sold by Bulk Molding Corporation. It is understood that other suitable non-metallic material may also be used without departing from the aims of the invention. Indeed, the anode plate 14 may be formed of various composite materials including, but not limited to, graphite particles imbedded in a thermosetting or thermoplastic polymer matrix.
The separator 16 is disposed between the cathode 12 and anode 14 plates prior to bonding of the fuel cell assembly 10. The separator 16 may be impregnated or coated with an adhesive prior to bonding. To increase the strength and durability of the fuel cell assembly 10, the separator 16 may be formed of a reinforcing material including, but not limited to, carbon fiber cloth, paper, cardboard, fiberglass or combinations thereof. It is appreciated that several techniques are known to those skilled in the art which are suitable for bonding the fuel assembly 10 and use of either of such techniques would not exceed the scope of the invention.
For metallic plates, the anode environment is the most damaging, since not only is the metal subject to an acidic environment, but the metal can be oxidized by the cell potential. By replacing the metallic anode with a composite anode plate 14 and bonding it to the metallic cathode plate 12, the worst features of the purely composite or metal fuel cell assemblies are avoided. The metal cathode plate 12 provides strength to the composite anode plate 14 while the composite anode plate 14 provides corrosion resistance to the harsh anode environment. The resulting fuel cell assembly 10 of the metal anode plate 12 and the composite cathode plate 14 may provide less weight than a purely metal fuel cell assembly while being thinner than a composite only assembly. Also, the feature tolerance that can be obtained on the anode plate 14 is not possible with the metal only fuel cell assembly. Further, the fuel cell assembly 10 also has an increased power density resulting from the bonded assembly being able to be made thinner.
It is to be understood that the above description is intended to be illustrative and not limiting. Many embodiments will be apparent to those of skill in the art upon reading the above description. Therefore, the scope of the invention should be determined, not with reference to the above description, but instead with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
