U.S. patent application number 10/389452 was filed with the patent office on 2004-09-16 for gasket material for a fuel cell.
Invention is credited to England, Diane M..
Application Number | 20040180254 10/389452 |
Document ID | / |
Family ID | 32771650 |
Filed Date | 2004-09-16 |
United States Patent
Application |
20040180254 |
Kind Code |
A1 |
England, Diane M. |
September 16, 2004 |
Gasket material for a fuel cell
Abstract
A solid-oxide fuel cell system comprising a plurality of
components having mating ports therebetween, the port interfaces
being sealed by gaskets that include fluorophlogopite mica
(F-mica).
Inventors: |
England, Diane M.;
(Bloomfield, NY) |
Correspondence
Address: |
DELPHI TECHNOLOGIES, INC.
M/C 480-410-202
PO BOX 5052
TROY
MI
48007
US
|
Family ID: |
32771650 |
Appl. No.: |
10/389452 |
Filed: |
March 14, 2003 |
Current U.S.
Class: |
429/425 |
Current CPC
Class: |
Y02T 90/40 20130101;
H01M 8/0612 20130101; H01M 8/2425 20130101; H01M 8/2415 20130101;
H01M 8/2483 20160201; F16J 15/102 20130101; H01M 2008/1293
20130101; H01M 8/2485 20130101; H01M 8/0276 20130101; H01M 8/021
20130101; H01M 8/0282 20130101; Y02E 60/50 20130101; H01M 2250/20
20130101; H01M 8/0273 20130101; H01M 8/0208 20130101 |
Class at
Publication: |
429/035 ;
429/038; 429/030 |
International
Class: |
H01M 002/08; H01M
008/02; H01M 008/12 |
Claims
What is claimed is:
1. A fuel cell assembly comprising a plurality of components
wherein at least one joint between two adjacent components is
sealed by a material including fluorophlogopite mica.
2. A fuel cell assembly in accordance with claim 1 wherein said
material is formed as a gasket.
3. A fuel cell assembly in accordance with claim 1 wherein said
components include passages for flow of gas and wherein said joint
is formed for the purpose of joining adjacent passages.
4. A fuel cell assembly in accordance with claim 1 wherein said
components include a fuel cell sub-assembly, a manifold, and a
hydrocarbon reformer.
5. A fuel cell assembly in accordance with claim 1 wherein said
assembly is an auxiliary power unit for a vehicle.
6. A fuel cell assembly in accordance with claim 1 wherein said
fluorophlogopite mica is of the formula
KMg.sub.3(AlSi.sub.3O.sub.10)F.su- b.2.
7. A fuel cell assembly in accordance with claim 1 wherein said
fuel cell sub-assembly includes a solid-oxide fuel cell.
8. A gasket for a fuel cell assembly comprising fluorophlogopite
mica.
Description
TECHNICAL FIELD
[0001] The present invention relates to fuel cells; more
particularly, solid-oxide fuel cell assemblies which operate at
elevated temperatures; and most particularly, to gasket material
for sealing joints between components of such fuel cell
assemblies.
BACKGROUND OF THE INVENTION
[0002] Fuel cells for combining hydrogen and oxygen to produce
electricity are well known. A known class of fuel cells includes a
solid oxide electrolyte layer through which oxygen anions migrate;
such fuel cells are referred to in the art as "solid-oxide" fuel
cells (SOFCs).
[0003] In some applications, for example, as an auxiliary power
unit (APU) for an automotive vehicle, an SOFC is preferably fueled
by "reformate" gas, which is the effluent from a catalytic gasoline
oxidizing reformer. Reformate typically includes amounts of carbon
monoxide (CO) as fuel in addition to molecular hydrogen. The
reforming operation and the fuel cell operation may be considered
as first and second oxidative steps of the liquid hydrocarbon,
resulting ultimately in water and carbon dioxide. Both reactions
are exothermic, and both are preferably carried out at relatively
high temperatures, for example, in the range of 700.degree. C. to
1000.degree. C.
[0004] A complete fuel cell assembly comprises a plurality of
components and sub-assemblies joined together mechanically to
provide the desired flow paths and control pathways for the liquid
hydrocarbon, reactive gases, spent gases, and cooling gases. It is
essential that the joints or interfaces between the components and
sub-assemblies be durably leak-free at temperatures from below
0.degree. C. to as high as 1000.degree. C., at pressures from
subatmospheric to up to several atmospheres. Such conditions place
very high demands on materials selected for gaskets at these joints
and interfaces.
[0005] It is known to use various glass and ceramic compositions as
sealants. However, a drawback is that such sealants, though
effective, tend to be quite brittle and are easily fractured in
assembly or in use. Further, typically they require
high-temperature sintering during manufacture of a fuel cell
system, which adds difficulty and cost.
[0006] What is needed is a material for gasketing in an SOFC system
which is thermally stable over the range between shutdown and
operating temperatures for both the reformer and the fuel cell
assembly; which is chemically stable in oxidizing and reducing
environments; which is more robust during assembly and during
operation of the system; which is compatible with other materials
of the system; and which is relatively inexpensive.
[0007] It is a principle object of the present invention to provide
an improved material for gasketing joints and seals in a fuel cell
assembly.
SUMMARY OF THE INVENTION
[0008] Briefly described, in a solid-oxide fuel cell assembly
comprising a plurality of components having mating ports
therebetween, the port interfaces are sealed by gaskets that
include fluorophlogopite mica (F-mica).
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] These and other features and advantages of the invention
will be more fully understood and appreciated from the following
description of certain exemplary embodiments of the invention taken
together with the accompanying drawings, in which:
[0010] FIG. 1 is an isometric view from above of a fuel cell
assembly having gasketing in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] The advantage and benefit of gasketing in accordance with
the invention may be best illustrated by considering the exemplary
gasketing requirements of an integrated SOFC fuel cell
assembly.
[0012] Referring to FIG. 1, fuel cell assembly 10 includes a
plurality of sub-assemblies and components assembled together
generally by bolts. An integrated base manifold 12 comprises a
bottom plate 14, and lower section 16, an intermediate plate 18, an
upper section 20, and a top plate 22. The plates 14, 18, 22 have
patterns of apertures (not visible) formed therein which mate with
other patterns of chambers (also not visible) formed in sections
16, 20 such that manifold 12 is a three-dimensional structure of
interwoven flow paths for various gases. Patterned sheet gaskets
24, 26, 28, 30 in accordance with the invention are provided
between the sections and plates to seal the port interfaces against
leakage of gases flowing through the manifold.
[0013] Fuel cell sub-assembly 32 is mounted on manifold 12, ports
(not visible) in the sub-assembly being mateable with ports (not
visible) in the manifold to provide reformate from the manifold
into the sub-assembly, to exhaust spent reformate from the
sub-assembly, and to provide cooling air to and from the assembly.
A patterned sheet gasket 34 is disposed therebetween to seal the
port interfaces against gas leakage. Manifold 12 and sub-assembly
32 are bolted together by bolts 36.
[0014] Fuel cell sub-assembly 32 also contains passage joints (not
visible) which are gasketed (not shown) between adjacent plates and
fuel cell modules.
[0015] A hydrocarbon fuel reformer 38 is mounted to manifold 12 via
bolts 40, having a patterned sheet gasket (not visible)
therebetween. A fuel pre-heater and vaporization sub-assembly 42 is
attached to reformer 38 for supplying heated and vaporized
hydrocarbon fuel to the reformer. A patterned sheet gasket 44 is
provided therebetween, and sub-assembly 42 is secured to reformer
38 via throughbolts 46.
[0016] A cover plate 48 for sub-assembly 42 supports a fuel
injector 50 for the reformer. A patterned sheet gasket 52 is
provided under the cover plate.
[0017] Heat exchangers 54a, 54b are mounted to manifold 12 via
bolts 56, having a patterned sheet gasket 58 therebetween.
[0018] Air inlet fittings 60a, 60b, 62 are received, as for example
by a threaded connection, into bores in manifold 12, the threads 64
preferably being sealed with gasket material.
[0019] The various patterned sheet gaskets and the thread-sealing
material include, and preferably are formed from, fluorophlogopite
mica (F-mica). F-mica, a synthetic fluorine mica believed to have
the formula KMg.sub.3(AlSi.sub.3O.sub.10)F.sub.2 contains no
(OH).sup.- of natural phlogopite
KMg.sub.3(AlSi.sub.3O.sub.10)(OH).sub.2. The (OH).sup.- is fully
substituted with F.sup.-. The fluorine mica has the following
unique characteristics which are much superior to those of natural
mica: high chemical stability, excellent transmittance,
outgassing-free at high temperature in vacuum, excellent electrical
insulation, high heat endurance (up to 1100.degree. C.),
non-radioactive background, and highly flexible and cleavable.
F-mica sheets may be made by the processes of, as for example,
screening, paper making, inorganic binder impregnating and hot
pressing etc. F-mica sheets are known in the prior art for a
variety of uses, such as substrates of thin film, windows and
monochromater for x-ray, neutron diffraction, microwave and optics,
spacers of electrical vacuum devices, scanning electron
microscopes, and water gauges of high pressure boilers, which uses
are important in industry and science. F-mica has not heretofore
been used for gasketing in high-temperature fuel cells, as
disclosed herein. Both sheet and tape forms of F-mica are
commercially available from, for example, G.B. Group, Inc., New
York, N.Y., USA, in thicknesses from 0.05 mm to 5 mm.
[0020] While the invention has been described by reference to
various specific embodiments, it should be understood that numerous
changes may be made within the spirit and scope of the inventive
concepts described. Accordingly, it is intended that the invention
not be limited to the described embodiments, but will have full
scope defined by the language of the following claims.
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