Solid oxide fuel cell interconnect

1 . A fuel cell interconnect, comprising:

a first surface comprising a first plurality of channels; and

a second surface comprising a second plurality of channels;

wherein:

a thickness of the interconnect measured between the first and second surfaces is substantially constant.

2 . The interconnect of claim 1 , wherein:

the first plurality of channels comprises a first series of channels disposed between a first series of ribs;

the second plurality of channels comprises a second series of channels disposed between a second series of ribs; and

the thickness of the interconnect measured between the first series of ribs and the second series of channels is substantially equal to the thickness of the interconnect measured between the first series of channels and the second series of ribs.

3 . The interconnect of claim 2 , wherein:

the first series of channels is aligned with the second series of ribs; and

the second series of channels is aligned with the first series of ribs.

4 . The interconnect of claim 2 , wherein:

the first series of ribs comprises a first pitch between adjacent ribs;

the second series of ribs comprises a second pitch between adjacent ribs;

the first pitch is substantially equal to the second pitch; and

the first and second series of ribs are offset from each other by a distance substantially equal to half the first or second pitch.

5 . The interconnect of claim 2 , wherein:

the first series of channels comprises cathode flow channels;

the second series of channels comprises anode flow channels;

the cathode flow channels comprise air flow channels; and

the anode flow channels comprise fuel flow channels.

6 . The interconnect of claim 5 , wherein:

the air flow channels are externally manifolded; and

the fuel flow channels are internally manifolded.

7 . The interconnect of claim 1 , wherein the interconnect is made by a process comprising powder metallurgy.

8 . The interconnect of claim 2 , wherein the first and the second series of channels comprise trapezoidal channels each having a base which is narrower than an opening, and the first and the second series of ribs comprise trapezoidal ribs each having a base which is wider than a tip.

9 . A fuel cell interconnect, comprising:

a first surface comprising a first plurality of channels; and

a second surface comprising a second plurality of channels;

wherein:

the first and second surfaces are disposed on opposite sides of the interconnect; and

the first plurality of channels is offset from the second plurality of channels.

10 . The interconnect of claim 9 , wherein:

the first plurality of channels is partially offset from the second plurality of channels.

11 . The interconnect of claim 10 , wherein:

the first plurality of channels comprises a first series of channels disposed between a first series of ribs;

the second plurality of channels comprises a second series of channels disposed between a second series of ribs; and

the first series of ribs is partially offset from the second series of ribs, such that the first series of ribs partially overlaps with both the second series of ribs and the second series of channels.

12 . The interconnect of claim 9 , wherein:

the first plurality of channels is completely offset from the second plurality of channels.

13 . The interconnect of claim 12 , wherein:

the first plurality of channels comprises a first series of channels disposed between a first series of ribs;

the second plurality of channels comprises a second series of channels disposed between a second series of ribs;

the first series of ribs is completely offset from the second series of ribs, such that the first series of ribs does not overlap with the second series of ribs;

the first and the second series of channels comprise trapezoidal channels each having a base which is narrower than an opening; and

the first and the second series of ribs comprise trapezoidal ribs each having a base which is wider than a tip.

14 . A fuel cell stack, comprising a fuel cell disposed between a first interconnect and a second interconnects; wherein:

the first and the second interconnects each comprise the interconnect of claim 9 ;

each major side of the cell is contacted by a contacting side of the first and the second interconnect; and

each contacting side of the first and the second interconnect comprises the first surface of the respective first and the second interconnect.

15 . The fuel cell stack of claim 14 , wherein the first plurality of channels of the first interconnect is aligned with the first plurality of channels of the second interconnect.

16 . The fuel cell stack of claim 15 , wherein:

the fuel cell comprises an electrolyte layer disposed between a cathode electrode and an anode electrode;

the cathode electrode is contacted by the contacting side of the first interconnect;

the anode electrode is contacted by the contacting side of the second interconnect;

the first series of channels of the first interconnect comprises cathode flow channels; and

the first series of channels of the second interconnect comprises anode flow channels.

17 . The fuel cell stack of claim 16 , wherein:

the cathode flow channels comprise air flow channels that are externally manifolded; and

the anode flow channels comprise fuel flow channels that are internally manifolded.

18 . The fuel cell stack of claim 14 , further comprising an end plate on each end of the stack.

19 . A fuel cell stack comprising a plurality of alternating plate-shaped fuel cells and interconnects, wherein:

each major side of each cell is contacted by ribs of two adjacent interconnects;

the ribs contacting a given cell are aligned with each other across the cell; and

the ribs on opposite sides of each interconnect are offset from each other.

20 . The fuel cell stack of claim 19 , wherein the ribs on opposite sides of each interconnect are offset from each other by a distance not equal to a pitch between adjacent ribs.

21 . The fuel cell stack of claim 20 , wherein the distance is substantially equal to half the pitch.

22 . The fuel cell stack of claim 19 , wherein:

each fuel cell comprises an electrolyte layer disposed between a cathode electrode and an anode electrode;

the stack is internally manifolded on the anode side of each fuel cell; and

the stack is externally manifolded on the cathode side of each fuel cell.

23 . The fuel cell stack of claim 19 , wherein:

ribs comprise trapezoidal ribs each having a base which is wider than a tip; and

the ribs are separated from each other by trapezoidal channels each having a base which is narrower than an opening.

24 . A method of making a fuel cell interconnect, comprising:

providing a metal powder into a die; and

sintering the metal powder in the die at an elevated temperature to form the interconnect;

wherein:

each major side of the interconnect comprises a series of ribs; and

the ribs on opposite sides of each interconnect are offset from each other.

25 . The method of claim 24 , further comprising pressing the powder before or during the step of sintering.

26 . The method of claim 25 , further comprising releasing the interconnect from the die and machining the interconnect after the step of releasing.

27 . The method of claim 24 , wherein:

the ribs comprise trapezoidal ribs each having a base which is wider than a tip; and

the ribs are separated by trapezoidal channels each having a base which is narrower than an opening.

28 . A fuel cell interconnect, comprising:

a first surface comprising a first plurality of alternating trapezoidal channels and ribs; and

a second surface comprising a second plurality of alternating trapezoidal channels and ribs.