Fuel cells employing integrated fluid management platelet technology
First Claim
1. An integrated fluid management microchannel architecture monolithic polar fuel cell separator for a PEM fuel cell, comprising in operative combination:
- (a) a plurality of platelets of thin metallic sheet material;
(b) each platelet having features formed therein prior to assembly into a separator, said features being selected from at least one of through-formed or depth-formed tabs, metering orifices, mixing chambers, lands, micro-channels, vias to convey fluids from one platelet to another, close outs, and manifolds;
(c) said features are interrelated and coordinate from platelet to platelet to provide in combination in an assembled separator;
i) at least one active area continuous micro-channel field in communication with at least one inlet via and one outlet via;
ii) at least one microchannel aqueous humidification field; and
iii) at least one micro-channel liquid coolant field;
(d) said platelets containing said lands, micro-channels and tabs upon bonding together forming micro-channel field structures of closely spaced, narrow micro-channels and substantially equal width lands, adjacent lands being held in configurational position by depth-formed tabs in at least one platelet, which tabs bridge across said channels to adjacent lands but do not obstruct flow of gaseous or liquid reactant through said micro-channels;
(e) said humidification and said coolant fields being integrated within said separator in substantially the same plane as an active field, or in a plane substantially parallel thereto, to provide integrated fluid and thermal management flow circuits; and
(f) upon assembly to form said separator said platelets are bonded together without glue along mating surfaces in the area of said fields to form a monolithic separator, said monolithic separator having internal micro-channel architecture features therein defining integrated fluid and thermal management flow circuits, said separator, upon use in contact with at least one electrode membrane assembly in a fuel cell stack, providing substantially higher power density than said solid graphite fuel cells.
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Accused Products
Abstract
Fuel cell stacks comprising stacked separator/membrane electrode assembly cells in which the separators comprise a series of stacked thin sheet platelets having individually configured serpentine micro-channel reactant gas humidification, active area and cooling fields therein. The individual platelets are stacked with coordinate features precisely aligned in contact with adjacent platelets and bonded to form a monolithic separator. Post bonding processing includes passivation, such as nitriding. Preferred platelet material is 4-25 mil Ti in which the features, serpentine channels, tabs, lands, vias, manifolds and holes, are formed by chemical or laser etching, cutting, pressing or embossing, with combinations of depth and through-etching being preferred. The platelet manufacturing process is continuous and fast. By employing CAD based platelet design and photolithography, rapid change in feature design to accommodate a wide range of thermal management and humidification techniques. 100 cell H2 --O2 /Air PEM fuel cell stacks of this IFMT platelet design will exhibit outputs on the order of 0.75 kW/kg, some 3-6 times greater than current graphite plate PEM stacks.
177 Citations
20 Claims
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1. An integrated fluid management microchannel architecture monolithic polar fuel cell separator for a PEM fuel cell, comprising in operative combination:
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(a) a plurality of platelets of thin metallic sheet material; (b) each platelet having features formed therein prior to assembly into a separator, said features being selected from at least one of through-formed or depth-formed tabs, metering orifices, mixing chambers, lands, micro-channels, vias to convey fluids from one platelet to another, close outs, and manifolds; (c) said features are interrelated and coordinate from platelet to platelet to provide in combination in an assembled separator; i) at least one active area continuous micro-channel field in communication with at least one inlet via and one outlet via; ii) at least one microchannel aqueous humidification field; and iii) at least one micro-channel liquid coolant field; (d) said platelets containing said lands, micro-channels and tabs upon bonding together forming micro-channel field structures of closely spaced, narrow micro-channels and substantially equal width lands, adjacent lands being held in configurational position by depth-formed tabs in at least one platelet, which tabs bridge across said channels to adjacent lands but do not obstruct flow of gaseous or liquid reactant through said micro-channels; (e) said humidification and said coolant fields being integrated within said separator in substantially the same plane as an active field, or in a plane substantially parallel thereto, to provide integrated fluid and thermal management flow circuits; and (f) upon assembly to form said separator said platelets are bonded together without glue along mating surfaces in the area of said fields to form a monolithic separator, said monolithic separator having internal micro-channel architecture features therein defining integrated fluid and thermal management flow circuits, said separator, upon use in contact with at least one electrode membrane assembly in a fuel cell stack, providing substantially higher power density than said solid graphite fuel cells. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification