EP0122150A2 — Integral gas seal for fuel cell gas distribution …

Claim 1

Independent Claim 122 words

An assembly for distributing reactant materials in a fuel cell comprising two adjacent electrically conductive plate members forming an interface therebetween where they contact each other, at least a first of said plate members being made of a porous material suitable for distributing reactant material from a surface thereof other than its surface forming said interface with the other plate member, the two plate members being integrally bonded to one another at their interface with a sealant material residing in the pores of said first plate member in the region of said interface whereby the two plate members maintain electrical contact with one another while preventing the reactant material from passing from said first plate to said other plate through said interface.

Claim 2

Dependent Claim 122 words

An assembly for distributing reactant materials in a fuel cell comprising two adjacent electrically conductive plate members forming an interface therebetween where they contact each other, at least a first of said plate members being made of a porous material suitable for distributing reactant material from a surface thereof other than its surface forming said interface with the other plate member, the two plate members being integrally bonded to one another at their interface with a sealant material residing in the pores of said first plate member in the region of said interface whereby the two plate members maintain electrical contact with one another while preventing the reactant material from passing from said first plate to said other plate through said interface.

Claim 3

Dependent Claim 66 words

An assembly as in Claim 1 wherein said other plate member is made of a porous material suitable for distributing another reactant material from a surface thereof other than its surface forming said interface with the first plate member thereby forming a bipolar distribution assembly and, further, wherein said sealant material also resides in the pores of said other plate member along said interface region thereof.

Claim 4

Dependent Claim 35 words

An assembly as in Claim 1 wherein each of said porous plates includes a plurality of substantially parallel grooves, the grooves of one plate being disposed substantially orthogonally to the grooves of the remaining plate.

Claim 5

Dependent Claim 28 words

An assembly as in Claim 1 wherein said porous plate member is made of a material selected from a reticulated vitreous carbon material, needled-felt carbon material, or graphite.

Claim 6

Dependent Claim 32 words

An assembly as in Claim 1 wherein the sealant material is a thermoplastic resin material selected from the group consisting of fluorinated ethylene-propylene, polysulphone, polyethersulfone, polyphenylsulphone, perfluorinated alkoxy tetrafluoroethylene, and mixtures thereof.

Claim 7

Dependent Claim 151 words

In a fuel cell stack assembly comprising a plurality of adjacent individual fuel cell units having contiguous porous gas distribution plates to form a bipolar assembly, the plates being separated from one another by a gas impermeable, electrically insulating barrier, whereby electrical contact is maintained between such plates, the improvement comprising: a composite bipolar assembly wherein contiguous electrically conductive porous plates are bonded in contact with one another along a common interface with a relatively insulating, thermoplastic sealant means; and said sealant means being principally distributed within the pores of each plate along said common interface to maintain substantial contact between said plates along said common interface whereby a secure physical union of each of said plates to the other with substantial electrical contact is maintained therebetween and a gas impermeable barrier is provided so as to prevent diffusion of reactants from one plate to the other across their common interface.

Claim 8

Dependent Claim 151 words

In a fuel cell stack assembly comprising a plurality of adjacent individual fuel cell units having contiguous porous gas distribution plates to form a bipolar assembly, the plates being separated from one another by a gas impermeable, electrically insulating barrier, whereby electrical contact is maintained between such plates, the improvement comprising: a composite bipolar assembly wherein contiguous electrically conductive porous plates are bonded in contact with one another along a common interface with a relatively insulating, thermoplastic sealant means; and said sealant means being principally distributed within the pores of each plate along said common interface to maintain substantial contact between said plates along said common interface whereby a secure physical union of each of said plates to the other with substantial electrical contact is maintained therebetween and a gas impermeable barrier is provided so as to prevent diffusion of reactants from one plate to the other across their common interface.

Claim 9

Dependent Claim 85 words

A process for producing a bipolar assembly for a fuel cell comprising: (a) providing at least two adjacent porous, conductive reactant distribution plates and a layer of sealant material positioned between said plates; and (b) applying pressure and elevated temperature to said plates and said layer to melt said layer and enable impregnation of the pores in the region of the plates along the adjacent surfaces of said plates whereby the plates are bonded together to form an integral bipolar assembly which is electrically conductive.

Claim 10

Dependent Claim 85 words

A process for producing a bipolar assembly for a fuel cell comprising: (a) providing at least two adjacent porous, conductive reactant distribution plates and a layer of sealant material positioned between said plates; and (b) applying pressure and elevated temperature to said plates and said layer to melt said layer and enable impregnation of the pores in the region of the plates along the adjacent surfaces of said plates whereby the plates are bonded together to form an integral bipolar assembly which is electrically conductive.

Claim 11

Dependent Claim 53 words

A process as in Claim 7 wherein said elevated temperature is between approximately 500° and 700°F., the pressure applied to said plates is at least approximately 200 lbs. per square inch, and said sealant material is selected from the group consisting of fluorinated. ethylene-propylene, polysulphone, polyethersulphone, polyphenylsulphone, perfluorinated alkoxy tetrafluoroethylene and mixtures thereof.

Claim 12

Dependent Claim 26 words

A process as in Claim 7 further comprising the step of placing grooves on opposite sides of said bipolar assembly to distribute fuel cell reactant materials.

Claim 13

Dependent Claim 99 words

A process for the preparation of a bipolar assembly of composite construction comprising: hot-pressing a sandwich consisting essentially of a film of thermoplastic sealant between two porous lamina at a temperature in the range of from about 500°-700°F and at a pressure of at least about 200 psi so as to effect essentially complete redistribution-of the sealant into the pores along the surface of each such lamina along their common interface; and maintaining the pressure exerted thereon while sufficiently cooling said sandwich so as to ensure that said lamina remain bonded to one another upon release of such pressure.

Claim 14

Dependent Claim 99 words

A process for the preparation of a bipolar assembly of composite construction comprising: hot-pressing a sandwich consisting essentially of a film of thermoplastic sealant between two porous lamina at a temperature in the range of from about 500°-700°F and at a pressure of at least about 200 psi so as to effect essentially complete redistribution-of the sealant into the pores along the surface of each such lamina along their common interface; and maintaining the pressure exerted thereon while sufficiently cooling said sandwich so as to ensure that said lamina remain bonded to one another upon release of such pressure.

Integral gas seal for fuel cell gas distribution assemblies and method of fabrication

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