Claims
- 1. A fuel cell stack comprising: a plurality of fuel cells electrically connected in series and having equivalent active section areas and circumferences, each fuel cell comprising a laminate of layers, these comprising an electrolyte membrane and catalyst, electrode and gas diffusion layers the functions of which may be combined in any combination in multifunction layers; end and separator plates delimiting each cell; and cooling layers the cooling function of which also may be combined with other layers in respective multifunction layers, the cooling layers each projecting beyond the circumferential outer periphery of the laminate of the other layers thereby comprising an inner active section area and a peripheral cooling fin area, wherein the ratio (14:15) of circumference and active area of the stack, defined by the geometrical shape of the active area, being greater than the corresponding ratio of a square active area, wherein the material of the cooling layers is a foil made of expanded graphite, which foil has a larger specific heat conductivity parallel to the plane of each fuel cell than orthogonal to that plane.
- 2. The fuel cell stack or claim 1, wherein an essentially rectangular active section area has a length exceeding the width by a factor of at least 1.5.
- 3. The fuel cell stack of claim 2, wherein an essentially rectangular active section area has a length exceeding the width by a factor of between 2.5 and 3.5.
- 4. The fuel cell stack of claim 1, wherein the cooling layers, in combination, also are the anodic and/or the cathodic electrodes.
- 5. The fuel cell stack of claim 1, wherein the cooling layers, in combination, also are the anodic and/or the cathodic gas diffusion layers.
- 6. The fuel cell stack of claim 1, wherein the cooling layers, in combination, also are the separator plates.
- 7. The fuel cell stack of claim 1, wherein the cooling layers have a channel structure in being provided with gas channels within the active section area.
- 8. The fuel cell stack of claim 1, wherein it comprises means for generating an enforced airflow traversing over the cooling fin areas of the cooling layers.
- 9. The fuel cell stack of claim 8 wherein the forced airflow is divided in at least two partial flows each traversing over a part of the cooling fin area.
- 10. The fuel cell stack of claim 8 wherein the airflow is supported partly or completely by the dynamic and/or static pressure of the ambient air with respect to a moving vehicle.
- 11. The fuel cell stack of claim 1, wherein the expanded graphite contains some distributed soot.
Parent Case Info
This application claims the benefit of U.S. Provisional Application No. 60/176,819 filed Jan. 19, 2000 and PCT/EP01/00438 filed Jan. 16, 2001.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/EP01/00438 |
|
WO |
00 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO01/54218 |
7/26/2001 |
WO |
A |
Foreign Referenced Citations (4)
Number |
Date |
Country |
01186768 |
Jan 1988 |
JP |
10162842 |
Nov 1996 |
JP |
WO 0154218 |
Jul 2001 |
WO |
WO 0154218 |
Jul 2001 |
WO |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/176819 |
Jan 2000 |
US |