US5620807A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flow field assembly for electrochemical fuel cells
Assignee: Dow Chemical Co
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Filing: 1995-08-31
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Granted: 1997-04-15
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Expires: 2015-08-31
Abstract
Abstract An electrochemical fuel cell having a membrane electrode assembly and a layer of an electrically conductive porous material adjacent thereto which has at least two portions with different mean pore sizes, wherein a first portion of the layer adjacent to the membrane electrode assembly has a porosity no greater than a second portion of the layer adjacent to the opposite side of the layer; the second portion has a porosity of at least about 82 percent; and the second portion has an mean pore size which is at least about 10 microns and at least ten times greater than the mean pore size of the first portion.
Inventors
- 👤 Robert D. Mussell
- 👤 Steven P. Webb
- 👤 Carey L. Scortichini
- 👤 Keith R. Plowman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 00:19
CPC Classifications
H; H01; H01M; H01M4/00; H01M4/86; H01M4/90; H01M4/92; H01M4/925; H01M4/926; H01M8/00; H01M8/10; H01M8/1004; H01M2300/00; H01M2300/0017; H01M2300/0065; H01M2300/0082; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
108 words
An electrochemical fuel cell having a membrane hydrated electrode assembly and a layer of an electrically conductive porous material adjacent thereto which has at least two portions with different mean pore sizes, wherein a first portion of the layer adjacent to the membrane electrode assembly has a porosity no greater than a second portion of the layer adjacent to the opposite side of the layer; the second portion has a porosity of at least about 82 percent; and the second portion has a mean pore size which is at least about 10 microns and at least ten times greater than the mean pore size of the first portion.
Claim 2
Dependent Claim
108 words
An electrochemical fuel cell having a membrane hydrated electrode assembly and a layer of an electrically conductive porous material adjacent thereto which has at least two portions with different mean pore sizes, wherein a first portion of the layer adjacent to the membrane electrode assembly has a porosity no greater than a second portion of the layer adjacent to the opposite side of the layer; the second portion has a porosity of at least about 82 percent; and the second portion has a mean pore size which is at least about 10 microns and at least ten times greater than the mean pore size of the first portion.
Claim 3
Dependent Claim
16 words
The fuel cell of claim 1 wherein the first portion of the porous layer is hydrophobic.
Claim 4
Dependent Claim
18 words
The fuel cell of claim 1 wherein the first portion of the porous layer comprises a polytetrafluoroethylene polymer.
Claim 5
Dependent Claim
18 words
The fuel cell of claim 1 wherein the first portion of the porous layer comprises a perfluoroalkyl/acrylic copolymer.
Claim 6
Dependent Claim
18 words
The fuel cell of claim 1 wherein the first portion of the porous layer comprises a perfluorocyclobutane polymer.
Claim 7
Dependent Claim
25 words
The fuel cell of claim 1 wherein the mean pore size of the first portion of the porous layer is at least about 0.1 micron.
Claim 8
Dependent Claim
25 words
The fuel cell of claim 1 wherein the mean pore size of the first portion of the porous layer is at least about 1 micron.
Claim 9
Dependent Claim
23 words
The fuel cell of claim 1 wherein the porosity of the second portion of the porous layer is at least about 82.5 percent.
Claim 10
Dependent Claim
27 words
The fuel cell of claim 1 wherein the porosity of the second portion of the porous layer on its second side is at least about 85 percent.
Claim 11
Dependent Claim
23 words
The fuel cell of claim 1 wherein the porosity of the second portion of the porous layer is at least about 87.5 percent.
Claim 12
Dependent Claim
21 words
The fuel cell of claim 1 wherein the second portion of the porous layer is more hydrophilic than the first portion.
Claim 13
Dependent Claim
25 words
The fuel cell of claim 1 wherein the first portion of the porous layer has a mean pore size of at least about 30 microns.
Claim 14
Dependent Claim
109 words
An electrochemical fuel cell having a membrane electrode assembly with a nonwoven porous layer of an electrically conductive porous material adjacent thereto which has at least two portions with different mean pore sizes, wherein a first portion of the layer adjacent to the membrane electrode assembly has a porosity no greater than a second portion of the layer adjacent to the opposite side of the layer; the second portion has a porosity of at least about 50 percent; and the second portion has an mean pore size which is at least about 35 microns and at least ten times greater than the mean pore size of the first portion.
Claim 15
Dependent Claim
109 words
An electrochemical fuel cell having a membrane electrode assembly with a nonwoven porous layer of an electrically conductive porous material adjacent thereto which has at least two portions with different mean pore sizes, wherein a first portion of the layer adjacent to the membrane electrode assembly has a porosity no greater than a second portion of the layer adjacent to the opposite side of the layer; the second portion has a porosity of at least about 50 percent; and the second portion has an mean pore size which is at least about 35 microns and at least ten times greater than the mean pore size of the first portion.
Claim 16
Dependent Claim
16 words
The fuel cell of claim 13 wherein the first portion of the porous layer is hydrophobic.
Claim 17
Dependent Claim
18 words
The fuel cell of claim 13 wherein the first portion of the porous layer comprises a polytetrafluoroethylene polymer.
Claim 18
Dependent Claim
18 words
The fuel cell of claim 13 wherein the first portion of the porous layer comprises a perfluoroalkyl/acrylic copolymer.
Claim 19
Dependent Claim
18 words
The fuel cell of claim 13 wherein the first portion of the porous layer comprises a perfluorocyclobutane polymer.
Claim 20
Dependent Claim
98 words
A process for preparing an electrochemical fuel cell having a membrane electrode assembly comprising the steps of: (a) applying a layer of a conductive composition to a sheet of a porous conductive material having a porosity of at least about 82 percent under conditions sufficient to form a porous, solid layer of the conductive composition on one side of the sheet of porous conductive material, forming a composite thereby, and (b) placing the composite adjacent to the membrane electrode assembly so that the side of the composite to which the conductive composition was applied is facing said assembly.
Claim 21
Dependent Claim
98 words
A process for preparing an electrochemical fuel cell having a membrane electrode assembly comprising the steps of: (a) applying a layer of a conductive composition to a sheet of a porous conductive material having a porosity of at least about 82 percent under conditions sufficient to form a porous, solid layer of the conductive composition on one side of the sheet of porous conductive material, forming a composite thereby, and (b) placing the composite adjacent to the membrane electrode assembly so that the side of the composite to which the conductive composition was applied is facing said assembly.
Claim 22
Dependent Claim
18 words
The process of claim 18 wherein the conductive composition comprises a polytetrafluoroethylene polymer, perfluoroalkyl/acrylic copolymer, or perfluorocyclobutane polymer.
Claim 23
Dependent Claim
32 words
The process of claim 19 wherein the conductive composition additionally comprises carbon fibers and/or powders and the weight ratio of the fibers and/or powders to the polymers is at least about 1:1.
Claim 24
Dependent Claim
32 words
The process of claim 19 wherein the conductive composition additionally comprises carbon fibers and/or powders and the weight ratio of the fibers and/or powders to the polymers is at least about 3:1.
Claim 25
Dependent Claim
33 words
The process of claim 19 wherein the conductive composition additionally comprises carbon fibers and/or powders and the weight ratio of the fibers and/or powders to the polymers is no greater than about 0:1.
Claim 26
Dependent Claim
33 words
The process of claim 20 wherein the conductive composition additionally comprises carbon fibers and/or powders and the weight ratio of the fibers and/or powders to the polymers is no greater than about 5:1.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-04-14 | 2000-10-14 | 2001-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-14 | 2004-10-14 | 2005-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-14 | 2008-10-14 | 2009-04-15 | $7700.00 | Window Closed / Lapsed |