US 7,070,874 B2Granted

Fuel cell end unit with integrated heat exchanger

AssigneeFuelCell Energy, Inc.

InventorsScott Blanchet, Pinakin Patel

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Abstract

An end unit for a fuel cell stack is described that contains an integrated heat exchanger for superheating the fuel gas before delivery to the stack. Heat is transferred from the hot cathode outlet stream to the cool fuel inlet stream in a space adjacent the stack's end plate. The end unit is designed as a hollow box forming the shell of the exchanger with the heat exchanger inside. The end unit has openings that allow fuel cell process gas to be taken directly from the stack without requiring piping or ductwork to be attached to thin manifolds. Separate chambers are provided for both the cathode outlet and anode outlet gas, thereby allowing all process connections to be made at one end of the stack. The end unit also features a current collection post that is separated from the end cell of the stack by a multitude of members which provide structural support for the end unit and act to more uniformly collect electrical current than would a single, large current post.

Claims35

Dependent claims

A fuel cell stack end unit for a fuel cell stack having a plurality of fuel cells stacked in a first direction, said end unit for stacking in said first direction adjacent an end fuel cell in said fuel cell stack, said end unit comprising:

an assembly having:
a first wall being adjacent said end cell when said end unit is stacked in said first direction in said fuel cell stack;
a second wall opposing said first wall;
a first side wall connecting said first and second walls;
a second side wall transverse to said first side wall and connecting said first and second walls;
a first inlet port receiving a first gas of said fuel cell stack when said end unit is stacked in said fuel cell stack;
and a second inlet port in said second side wall for receiving a second gas of said fuel cell stack when said end unit is stacked in said fuel cell stack;
said assembly conveying said first and second gases in heat exchange relationship and outputting said gases after heat is transferred from one gas to another when said end unit is stacked in said fuel stack;
a third side wall opposing said first side wall and connecting said first and second walls;
a fourth side wall opposing said second side wall and connecting said first and second walls;
a first outlet port in at least one of said first and third side walls for outputting said first gas after undergoing heat exchange in said assembly;
and a second outlet port in said fourth side wall for outputting said second gas after said second gas undergoes heat exchange in said assembly;
wherein said assembly further includes:
an interior wall extending between said first and second walls and said second and fourth side walls, said interior wall being spaced from said third side wall and forming with said first and second walls and said second and fourth side walls a chamber;
a third inlet port in said third side wall for receiving in said chamber a third gas of said fuel cell stack when said end unit is stacked in said fuel cell stack;
and a third outlet port in said second side wall for outputting said third gas after passage through said chamber.

13 more elements

an assembly:
having a first wall being adjacent said end cell when said end unit is stacked in said first direction in said fuel cell stack, a second wall opposing said first wall;
a first side wall connecting said first and second walls;
a second side wall transverse to said first side wall and connecting said first and second walls;
a first inlet port receiving a first gas of said fuel cell stack when said end unit is stacked in said fuel cell stack;
and a second inlet port in said second side wall for receiving a second gas of said fuel cell stack when said end unit is stacked in said fuel cell stack;
said assembly conveying said first and second gases in heat exchange relationship and outputting said gases after heat is transferred from one gas to another when said end unit is stacked in said fuel stack;
a third side wall opposing said first side wall and connecting said first and second walls;
a fourth side wall opposing said second side wall and connecting said first and second walls;
a first outlet port in at least one of said first and third side walls for outputting said first gas after undergoing heat exchange in said assembly;
and a second outlet port in said fourth side wall for outputting said second gas after said second gas undergoes heat exchange in said assembly;
wherein said assembly further comprises:
a first unit for defining an enclosed gas flow path for said first gas;
and said first and second walls and said first, second, third and fourth side walls forming an enclosure of a second unit enclosing said first unit and defining a gas flow path for said second gas intersecting said first unit, wherein said first and second units act as a heat exchanger transferring heat from said second gas to said first gas.

11 more elements

A fuel cell stack comprising:

a plurality of fuel cells stacked in a first direction and a fuel cell stack end unit stacked along said first direction adjacent an end fuel cell at each end of the stack, one of said fuel cell stack end units including an assembly having:
a first wall being adjacent said end cell;
a second wall opposing said first wall;
a first side wall connecting said first and second walls;
a second side wall transverse to said first side wall and connecting said first and second walls;
a first inlet port receiving a first gas of said fuel cell stack;
and a second inlet port in said second side wall for receiving a second gas of said fuel cell stack;
said assembly conveying said first and second gases in heat exchange relationship and outputting said gases after heat is transferred from one gas to another;
a third side wall opposing said first side wall and connecting said first and second walls;
a fourth side wall opposing said second side wall and connecting said first and second walls;
a first outlet port in at least one of said first and third side walls for outputting said first gas after said first gas undergoes heat exchange in said assembly;
and a second outlet port in said fourth side wall for outputting said second gas after said second gas undergoes heat exchange in said assembly;
and wherein said assembly further comprises:
a first unit for defining an enclosed gas flow path for said first gas;
and said first and second walls and said first, second, third and fourth side walls forming an enclosure of a second unit enclosing said first unit and defining a gas flow path for said second gas intersecting said first unit, wherein said first and second units act as a heat exchanger transferring heat from said second gas to said first gas.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/329,182Filed 24 Dec 2002
Published: US 2004/0121205 A124 Jun 2004
Granted: 4 Jul 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H01M 8/04014
Related to heat exchange: heat exchange using gaseous fluids; Heat exchange by combustion of reactants
H01M 8/0267
Collectors; Separators, e.g. bipolar separators; Interconnectors: having heating or cooling means, e.g. heaters or coolant flow channels
H01M 8/2457
Grouping of fuel cells, e.g. stacking of fuel cells: with both reactants being gaseous or vaporised
H01M 8/2484
Details of groupings of fuel cells: characterised by external manifolds