Anode splitter plate and methods for making the same

Patent metadata

Field	Value
Publication number	US-2017222236-A1
Application number	US-201715422677-A
Country	US
Kind code	A1
Filing date	Feb 2, 2017
Priority date	Feb 3, 2016
Publication date	Aug 3, 2017
Grant date	—

Abstract

Various embodiments of a reactant feed and return assembly, such as an anode splitter plate (ASP), are provided for facilitating reactant feed and exhaust flow in a solid oxide fuel cell (SOFC) stack system. Embodiments include a reactant feed and return assembly including at least a first portion formed of a chromium-based alloy, such as a chromium-iron alloy, having a similar coefficient of thermal expansion as other SOFC components and may therefore reduce internal stress in an SOFC stack. Methods for making an a reactant feed and return assembly comprising a chromium-based alloy are also provided.

First claim

1 . A reactant feed and return assembly for a fuel cell stack system, comprising:
a reactant feed opening in the reactant feed and return assembly for fluid engagement with a reactant feed conduit; a reactant exhaust opening in the reactant feed and return assembly for fluid engagement with a reactant exhaust conduit; a reactant feed channel within the reactant feed and return assembly configured to provide fluid communication between the reactant feed conduit and an inlet riser opening of a fuel cell stack; and a reactant exhaust channel within the reactant feed and return assembly configured to provide fluid communication between the anode exhaust conduit and an outlet riser opening of a fuel cell stack, wherein the reactant feed and return assembly comprises at least a first portion made from a chromium-based alloy comprising at least about 80% chromium by weight.

2 . The reactant feed and return assembly of claim 1 , wherein the at least one first portion of the reactant feed and return assembly comprises at least one outer surface of the assembly that contacts an end plate of a fuel cell stack in an assembled fuel cell stack system.

3 . The reactant feed and return assembly of claim 2 , wherein:
the reactant feed and return assembly comprises an anode splitter plate (ASP); the at least one first portion of the reactant feed and return assembly comprises first and second outer surfaces of the reactant feed and return assembly, wherein the first outer surface contacts an end plate of a first fuel cell stack and the second outer surface contacts an end plate of a second fuel cell stack in the assembled fuel cell stack system; the reactant feed channel is configured to provide fluid communication between the reactant feed conduit and inlet riser openings of the respective first and second fuel cell stacks; and the reactant exhaust channel is configured to provide fluid communication between the reactant exhaust conduit and outlet riser openings of the respective first and second fuel cell stacks.

4 . The reactant feed and return assembly of claim 3 , wherein the chromium-iron alloy comprises approximately 94-96% chromium by weight and approximately 4-6% iron by weight.

5 . The reactant feed and return assembly of claim 4 , wherein the chromium-iron alloy further comprises approximately 0.02-0.2% yttrium or yttria, and a maximum of approximately 0.45% of residual or unavoidable impurities.

6 . The reactant feed and return assembly of claim 2 , wherein the at least one first portion of the reactant feed and return assembly comprises at least one cover plate formed of the chromium-based alloy.

7 . The reactant feed and return assembly of claim 6 , wherein the at least one cover plate is formed by a powder metallurgy powder pressing process.

8 . The reactant feed and return assembly of claim 6 , wherein the at least one cover plate is formed by a sheet metal forming process.

9 . The reactant feed and return assembly of claim 6 , wherein:
the at least one first portion of the reactant feed and return assembly comprises first and second cover plates bonded to first and second major surfaces of a central plate; and the central plate comprises open regions which define the reactant feed channel and the reactant exhaust channel when the first and second cover plates are bonded to the central plate.

10 . The reactant feed and return assembly of claim 9 , wherein the first and second cover plates are bonded to the central plate by a brazing material.

11 . The reactant feed and return assembly of claim 10 , wherein the central plate comprises a metal material having less than about 50% chromium by weight.

12 . The reactant feed and return assembly of claim 11 , wherein at least one of:
(a) the central plate comprises at least one of grade 446 stainless steel or an Inconel alloy; and (b) the brazing material comprises at least one of a BNi5 and a BNi9 paste.

13 . The reactant feed and return assembly of claim 10 , wherein the central plate comprises a chromium-based alloy comprising at least about 80% chromium by weight and is formed by a powder metallurgy powder pressing process.

14 . The reactant feed and return assembly of claim 6 , wherein the reactant feed and return assembly comprises first and second cover plates that are bonded together to form a main body of the reactant feed and return assembly.

15 . The reactant feed and return assembly of claim 14 , wherein at least one of the first and second cover plates comprises grooves formed in a surface of the cover plate which define the reactant feed channel and the reactant exhaust channel when the first and second cover plates are bonded together.

16 . The reactant feed and return assembly of claim 15 , wherein at least one of:
(a) the first cover plate comprises grooves formed in a surface and the second cover plate comprises a substantially flat surface that interfaces with the first cover plate; (b) both the first cover plate and the second cover plate comprise grooves formed in their respective interfacing surfaces; and (c) the first and second cover plates are bonded together by a brazing material.

17 . The reactant feed and return assembly of claim 1 , further comprising:
first and second projection portions extending from a side of the reactant feed and return assembly, the reactant feed channel extending between the first projection portion and the inlet riser opening and the reactant exhaust channel extending between the second projection and the outlet riser opening; at least one first tube member bonded to the first projection portion and in fluid communication with the reactant feed channel; and at least one second tube member bonded to the second projection portion and in fluid communication with the reactant exhaust channel.

18 - 25 . (canceled)

26 . A fuel cell stack system, comprising:
a column comprising at least a first fuel cell stack and a second fuel cell stack; and a reactant feed and return assembly located between the first fuel cell stack and the second fuel cell stack in the column, wherein at least the outer surfaces of the reactant feed and return assembly that contact the respective end plates of the first fuel cell stack and the second fuel cell stack are formed of a material that has a coefficient of thermal expansion (CTE) that differs from the CTE of the respective end plates of the first fuel cell stack and the second fuel cell stack by less than 1.3×10 −6 K −1 over an operating temperature of the fuel cell stack system.

27 - 28 . (canceled)

29 . A method of fabricating a reactant feed and return assembly for a fuel cell stack, comprising:
providing a metal powder in a preform shape corresponding to a first portion of the reactant feed and return assembly; sintering the metal powder in the preform shape; and bonding the first portion of the reactant feed and return assembly to at least one second portion of the reactant feed and return assembly using a brazing material.

30 - 45 . (canceled)

Assignees

• Bloom Energy Corp

Inventors

• Armstrong Tad
• Perry Martin
• Verma Avinash
• Petrucha Michael
• Shi Dongai
• Lin Cheng-Yu
• Baharani Shruti

Classifications

• C22C19/05

  with chromium · CPC title

• B23K35/304

  with Cr as the next major constituent · CPC title

• C22C19/058

  without Mo and W · CPC title

• H01M8/2457

  with both reactants being gaseous or vaporised · CPC title

• H01M8/021

  Alloys based on iron · CPC title