U.S. patent application number 15/909417 was filed with the patent office on 2018-07-05 for separator for fuel cell, method of fabricating the same, and fuel cell electrode assembly.
The applicant listed for this patent is AMOGREENTECH CO., LTD.. Invention is credited to In Yong SEO.
Application Number | 20180191001 15/909417 |
Document ID | / |
Family ID | 58386420 |
Filed Date | 2018-07-05 |
United States Patent
Application |
20180191001 |
Kind Code |
A1 |
SEO; In Yong |
July 5, 2018 |
SEPARATOR FOR FUEL CELL, METHOD OF FABRICATING THE SAME, AND FUEL
CELL ELECTRODE ASSEMBLY
Abstract
Provided are a separator for a fuel cell, a method of
manufacturing the same, and a fuel cell electrode assembly, The
fuel cell separator includes: a first support formed by
accumulating a polymer fiber and having a plurality of first pores;
a first ion exchange resin filled in the plurality of first pores
of the first support by droplets of the first ion exchange resin
obtained by electrospraying the first ion exchange resin on the
first support; a second support formed by accumulating a polymer
fiber on the first support and having a plurality of second pores;
and a second ion exchange resin filled in the plurality of second
pores of the second support by droplets of the second ion exchange
resin obtained by electrospraying the second ion exchange resin on
the second support.
Inventors: |
SEO; In Yong; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AMOGREENTECH CO., LTD. |
Gimpo-si |
|
KR |
|
|
Family ID: |
58386420 |
Appl. No.: |
15/909417 |
Filed: |
March 1, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/KR2016/010512 |
Sep 21, 2016 |
|
|
|
15909417 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02E 60/50 20130101;
H01M 8/109 20130101; H01M 8/1062 20130101; Y02P 70/50 20151101;
H01M 8/0239 20130101; H01M 8/106 20130101; H01M 8/0245 20130101;
H01M 2008/1095 20130101 |
International
Class: |
H01M 8/0239 20060101
H01M008/0239; H01M 8/0245 20060101 H01M008/0245 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 24, 2015 |
KR |
10-2015-0135183 |
Claims
1. A fuel cell separator comprising: a first support having a
plurality of first pores; a first ion exchange resin filled in the
plurality of first pores of the first support; a second support
stacked on the first support and having a plurality of second
pores; and a second ion exchange resin filled in the plurality of
second pores of the second support.
2. The fuel cell separator of claim 1, wherein the first support
and the second support comprise nanofiber membranes having pores of
a three-dimensional network structure and formed by accumulating
electrospun polymer fibers, respectively.
3. The fuel cell separator of claim 1, wherein the sizes of the
first and second pores are in a range of 0.2 .mu.m to 1.5
.mu.m.
4. The fuel cell separator of claim 1, wherein the thicknesses of
the first and second supports are each be in a range of 1 .mu.m to
3 .mu.m.
5. The fuel cell separator of claim 2, wherein the polymer fibers
are elastic polymer fibers.
6. The fuel cell separator of claim 2, wherein the polymer fibers
comprise 20 wt % to 50 wt % of a fiber-forming polymer and 50 wt %
to 80 wt % of a heat-resistant polymer.
7. An electrode assembly for a fuel cell comprising: a cathode; an
anode; and a fuel cell separator according to claim 1, which is
interposed between the cathode and the anode.
8. A method of manufacturing a separator for a fuel cell comprising
the steps of: accumulating fibers obtained by electrospinning a
spinning solution in which a polymer and a solvent are mixed to
obtain a first support having a plurality of first pores in a
three-dimensional network structure; electrospraying a spraying
solution in which a first ion exchange resin and a solvent are
mixed to thereby spray droplets of the first ion exchange resin on
the first support body and fill the droplets of the first ion
exchange resin in the plurality of first pores of the first
support; accumulating fibers obtained by electrospinning a spinning
solution in which a polymer and a solvent are mixed on the first
support to thus form a second support having a plurality of second
pores in a three-dimensional network structure; and electrospraying
a spraying solution in which a second ion exchange resin and a
solvent are mixed to thereby spray droplets of the second ion
exchange resin on the second support body and fill the droplets of
the second ion exchange resin in the plurality of second pores of
the second support.
9. The method of claim 8, wherein after filling the plurality of
second pores of the second support with the droplets of the second
ion exchange resin, heat processing or thermal calendering of the
first and second supports is further performed.
10. The method of claim 8, wherein a spraying amount of the
spraying solution for forming droplets of the ion exchange resin is
twice to three times a spinning amount of the spinning solution for
forming the first and second supports.
11. The method of claim 8, wherein the sizes of the first and
second pores are in a range of 0.2 .mu.m to 1.5 .mu.m.
12. The method of claim 8, wherein the fibers constituting the
first and second supports comprise 20 wt % to 50 wt % of a
fiber-forming polymer and 50 wt % to 80 wt % of a heat-resistant
polymer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a separator for a fuel
cell, and more particularly, to a separator for a fuel cell, a
manufacturing method thereof, and a fuel cell electrode assembly
capable of realizing an ultra-thin structure, reducing a
manufacturing process, and preventing damage to a support due to
charging and discharging energy.
BACKGROUND ART
[0002] Recently, an energy problem has become a big concern as the
industry is highly developed.
[0003] Accordingly, there is a growing demand for new energy
sources that are environmentally friendly and have high power.
[0004] The fuel cell is an energy conversion device that converts
the chemical energy of fuel into electric energy. The fuel cell has
high energy density and high efficiency, and is expected to be used
as an environmentally friendly energy source.
[0005] The fuel cell generates electric energy from the chemical
reaction energy of hydrogen contained in a hydrocarbon-based
material such as methanol, ethanol, and natural gas and oxygen
supplied from the outside. Depending on the kind of the
electrolyte, the fuel cell is classified into a Phosphoric Acid
Fuel Cell (PAFC), a Molten Carbonate Fuel Cell (MCFC), a Solid
Oxide Fuel Cell (SOFC), a Polymer Electrolyte Membrane Fuel Cell
(PEMFC), and the like.
[0006] Among the fuel cells, the Polymer Electrolyte Fuel Cell
(PEMFC) has excellent output characteristics, can solve a corrosion
problem by using a solid polymer membrane, has the quick start and
response characteristics, and can obtain the high energy conversion
efficiency and high current density at low temperature.
Accordingly, the Polymer Electrolyte Fuel Cell (PEMFC) is applied
in various fields such as an automobile power supply, distributed
power supply, and small power supply.
[0007] Korean Patent Application Publication No. 10-2013-0001294
proposed a technique for preventing wrinkles from being formed in a
solid polymer electrolyte membrane of a fuel cell by thermally
transferring an electrode catalyst layer to either surface of the
solid polymer electrolyte membrane using a protective film.
Accordingly, it is possible to prevent the electrode catalyst layer
from being peeled off by the wrinkles of the solid polymer
electrolyte membrane. However, since the thermal expansion
coefficient of the solid polymer electrolyte membrane is different
from that of the electrode catalyst layer, the electrode catalyst
layer may be peeled off from the solid polymer electrolyte membrane
and the mechanical strength of the solid polyelectrolyte membrane
may be lowered during charging and discharging, due to the heat
generated when the fuel cell is driven. As a result, the fuel cell
may be deformed or damaged to lower the reliability of the fuel
cell. Therefore, it is required to develop a separator for a fuel
cell having a new structure capable of improving reliability.
DISCLOSURE
Technical Problem
[0008] The present invention has been conceived in view of the
above points, and an object of the present invention is to provide
a separator for a fuel cell, a manufacturing method thereof, and a
fuel cell electrode assembly, in which a support is formed by
accumulating fibers obtained by electrospinning, and droplets of an
ion exchange resin are sprayed on the support to thereby fill a
plurality of pores of the support with the ion exchange resin, to
thus realize an ultra-thin structure and reduce a manufacturing
process.
[0009] Another object of the present invention is to provide a
separator for a fuel cell, which is capable of preventing damage to
a support due to charging and discharging energy and thus improving
reliability, a method of manufacturing the separator, and a fuel
cell electrode assembly.
[0010] Still another object of the present invention is to provide
a separator for a fuel cell and a method of manufacturing the same,
in which a multi-layer structure is formed by repeating an
electrospinning process of forming a support of a pore structure
and an electrospraying process of spraying droplets of an ion
exchange resin into the support and filling the pores with the ion
exchange resin in turn to increase a filling rate of the ion
exchange resin.
Technical Solution
[0011] According to an aspect of the present invention, there is
provided a fuel cell separator comprising: a first support having a
plurality of first pores; a first ion exchange resin filled in the
plurality of first pores of the first support; a second support
stacked on the first support and having a plurality of second
pores; and a second ion exchange resin filled in the plurality of
second pores of the second support.
[0012] The first support and the second support may be composed of
nanofiber membranes having pores of a three-dimensional network
structure and formed by accumulating electrospun polymer fibers,
respectively.
[0013] In the fuel cell separator according to an embodiment of the
present invention, the sizes of the first and second pores may be
in a range of 0.2 .mu.m to 1.5 .mu.m, and the thicknesses of the
first and second supports may each be in a range of 1 .mu.m to 3
.mu.m.
[0014] In the fuel cell separator according to an embodiment of the
present invention, the polymer fibers may be elastic polymer
fibers.
[0015] In addition, the polymer fibers may contain 20 wt % to 50 wt
% of a fiber-forming polymer and 50 wt % to 80 wt % of a
heat-resistant polymer.
[0016] According to another aspect of the present invention, an
electrode assembly for a fuel cell includes a cathode, an anode,
and a separator for the fuel cell interposed between the cathode
and the anode.
[0017] According to still another aspect of the present invention,
a method of manufacturing a separator for a fuel cell comprises the
steps of: accumulating fibers obtained by electrospinning a
spinning solution in which a polymer and a solvent are mixed to
obtain a first support having a plurality of first pores in a
three-dimensional network structure; electrospraying a spraying
solution in which a first ion exchange resin and a solvent are
mixed to thereby spray droplets of the first ion exchange resin on
the first support body and fill the droplets of the first ion
exchange resin in the plurality of first pores of the first
support; accumulating fibers obtained by electrospinning a spinning
solution in which a polymer and a solvent are mixed on the first
support to thus form a second support having a plurality of second
pores in a three-dimensional network structure; and electrospraying
a spraying solution in which a second ion exchange resin and a
solvent are mixed to thereby spray droplets of the second ion
exchange resin on the second support body and fill the droplets of
the second ion exchange resin in the plurality of second pores of
the second support.
[0018] In the method of manufacturing a separator for a fuel cell
according to an embodiment of the present invention, after filling
the plurality of second pores of the second support with the
droplets of the second ion exchange resin, heat treating or thermal
calendering of the first and second supports may be further
performed.
[0019] In the method of manufacturing a separator for a fuel cell
according to an embodiment of the present invention, a spraying
amount of the spraying solution for forming droplets of the ion
exchange resin may be twice to three times the spinning amount of
the spinning solution for forming the first and second
supports.
Advantageous Effects
[0020] As described above, in some embodiments of the present
invention, an electrospinning process and an electrospraying
process are sequentially performed so that the droplets of the ion
exchange resin obtained by electrospraying are applied to the
support formed between the fibers obtained by electrospinning, and
the droplets of the applied ion exchange resin are spontaneously
filled into the pores of the support, to thus achieve the separator
for a fuel cell having an ultra-thin structure while reducing the
manufacturing process.
[0021] In some embodiments of the present invention, an
electrospinning process for forming a support of a pore structure
and an electrospraying process for spraying droplets of an ion
exchange resin into the pores to thus fill the former into the
latter, are alternately repeated to form a multi-layer structure,
thereby maximizing a filling rate of the ion exchange resin.
[0022] When the filling rate of the ion exchange resin is improved
in the separator as described above, the ion exchange capacity is
improved, and the performance of moving proton (P) generated in an
anode by a supply of a fuel gas toward a cathode is improved. As a
result, the performance of the fuel cell may be improved as the
proton transferred through the separator and the oxygen of an
oxidant gas supplied from the outside react with each other quickly
and effectively at the cathode.
[0023] In some embodiments of the present invention, since a
plurality of pores of a support having a three-dimensional network
structure are filled with an ion exchange resin, it is possible to
realize a fuel cell having excellent reliability by preventing
desorption of the ion exchange resin even in charging and
discharging.
[0024] In some embodiments of the present invention, a support
containing an ion exchange resin in pores is formed by accumulating
fibers containing an elastic polymer. Accordingly, the support
excellent in elasticity may be obtained, and the support may be
shrunk and expanded upon charging and discharging of the fuel cell,
to thereby prevent damage to the support.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a flowchart of a method of manufacturing a
separator for a fuel cell according to a first embodiment of the
present invention.
[0026] FIGS. 2A to 2D are views for explaining a method of
manufacturing a separator for a fuel cell according to the first
embodiment of the present invention.
[0027] FIG. 3 is a conceptual cross-sectional view of a separator
for a fuel cell according to the first embodiment of the present
invention.
[0028] FIG. 4 is a flowchart of a method of manufacturing a
separator for a fuel cell according to a second embodiment of the
present invention.
[0029] FIG. 5 is a flowchart of a method of manufacturing a
separator for a fuel cell according to a third embodiment of the
present invention.
[0030] FIG. 6 is a cross-sectional view of an electrode assembly
for a fuel cell according to an embodiment of the present
invention.
BEST MODE
[0031] Hereinafter, embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
[0032] Referring to FIG. 1, a method of manufacturing a separator
for a fuel cell according to a first embodiment of the present
invention includes: forming a first support having a plurality of
first pores in a three-dimensional structure by accumulating fibers
obtained by electrospinning a spinning solution mixed with a
polymer and a solvent (S100).
[0033] The spinning method that may be applied for the present
invention may employ any one of electrospinning,
air-electrospinning (AES), electrospraying, electrobrown spinning,
centrifugal electrospinning, and flash-electrospinning.
[0034] That is, the electrospinning can be performed by any
electrospinning method including bottom-up electrospinning,
top-down electrospinning, air spinning, or the like.
[0035] The polymer for the spinning solution may be any one of low
polymer polyurethane, high polymer polyurethane, polystyrene (PS),
polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), polylactic
acid (PLA), polyethylene oxide (PEO), polyvinyl acetate (PVAc),
polyacrylic acid (PAA), polycaprolactone (PCL), polyacrylonitrile
(PAN), polyvinylpyrrolidone (PVP), polyvinylchloride (PVC), nylon,
polycarbonate (PC), polyetherimide (PEI), polyvinylidene fluoride
(PVdF), polyesthersulphone (PES), or a mixture thereof.
[0036] The solvent may employ one or more selected from the group
consisting of dimethyl acetamide (DMA), N, N-dimethylformamide
(DMF), N-methyl-2-pyrrolidinone (NMP), dimethyl sulfoxide (DMSO),
tetrahydrofuran di-methylacetamide (DMAc), ethylene carbonate (EC),
diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl
carbonate (EMC), propylene carbonate (PC), water, acetic acid, and
acetone.
[0037] Then, droplets of a first ion exchange resin obtained by
electrospinning a spinning solution containing a mixture of the
first ion exchange resin and a solvent are applied to the first
support, and the droplets of the first ion exchange resin are
filled into a plurality of first pores of the first support (S110).
In this case, for example, a fluorine-based resin may be used as
the ion exchange resin.
[0038] Next, fibers obtained by electrospinning the spinning
solution mixed with the polymer and the solvent onto the first
support are accumulated to form a second support having a plurality
of second pores of a three-dimensional network structure
(S120).
[0039] Subsequently, droplets of a second ion exchange resin
obtained by electrospinning a spraying solution containing a
mixture of the second ion exchange resin and a solvent are applied
to the second support, and the droplets of the second ion exchange
resin are filled in the plurality of second pores of the second
support (S130).
[0040] When the steps S100 to S130 are performed, a fuel cell
separator is manufactured in which the fuel cell separator
includes: a first support formed by accumulating polymer fibers and
having a plurality of first pores; a first ion exchange resin
filled in the plurality of first pores of the first support by
droplets of the first ion exchange resin obtained by being
electrosprayed on the first support; a second support formed by
accumulating polymer fibers on the first support and having a
plurality of second pores; and a second ion exchange resin filled
in the plurality of second pores of the second support by droplets
of the second ion exchange resin obtained by being electrosprayed
on the second support.
[0041] In some embodiments of the present invention, the
above-described processes may be repeatedly performed to produce a
fuel cell separator that is formed by laminating a plurality of
first and second supports in which the first and second ion
exchange resins are filled in the pores of the first and second
supports, respectively. As a result, an electrospinning process for
forming a support of a pore structure and an electrospraying
process for spraying droplets of an ion exchange resin into the
pores to thus fill the former into the latter, are alternately
repeated to form a multi-layer structure, thereby maximizing a
filling rate of the ion exchange resin.
[0042] Referring to FIGS. 2A to 2D, a method of manufacturing a
separator for a fuel cell according to the first embodiment of the
present invention will be described in more detail.
[0043] A separator for a fuel cell is formed by alternately
performing electrospinning and electrospraying to fill pores of
supports with droplets of an ion exchange resin.
[0044] The supporters 110 and 130 are formed by accumulating fibers
obtained by electrospinning a spinning solution and are electrospun
to a collector 20 from first and second spinning nozzles 51 and 53
to which the spinning solution is supplied and are realized in a
web structure having a plurality of pores formed by accumulating
the fibers on the collector 20.
[0045] Here, a grounded collector 20 in the form of a conveyor that
moves at a constant speed is deployed at a lower portion spaced
apart from the first and second spinning nozzles 51 and 53. When a
high voltage electrostatic force is applied between the collector
20 and each of the spinning nozzles 51 and 53, the spinning
solution is discharged to the fibers 110 from the first and second
spinning nozzles 51 and 53 to then be spun onto the collector
20.
[0046] Then, when the spraying solution in which the ion exchange
resin and the solvent are mixed is electrosprayed to the supports
110 and 130 by first and second spray nozzles 52 and 54, droplets
of the ion exchange resin are discharged from the first and second
spray nozzles 52 and 54, and the droplets of the ion exchange resin
are applied onto the supports 110 and 130. The droplets of the ion
exchange resin applied onto the supports 110 and 130 permeate and
are filled into the plurality of pores of the supports by a
spraying energy or spontaneously.
[0047] That is, the first fiber 111 discharged from the first
spinning nozzle 51 is accumulated onto the collector 20 to form the
first support 110 (see FIG. 2A). Then, after the first support 110
is moved to the lower portion of the first spray nozzle 52, the
droplets 121 of the first ion exchange resin sprayed from the first
spray nozzle 52 are applied to the first support 110 (see FIG.
2B).
[0048] Here, the droplets 121 of the first ion exchange resin
rapidly penetrates into the plurality of pores of the first support
110 due to the spraying energy, and spontaneously permeate and are
filled into the plurality of pores of the first support 110, due to
the flowability of the first ion exchange resin.
[0049] Then, the first support 110 filled with the droplets 121 of
the first ion exchange resin is moved to the lower portion of the
second spinning nozzle 53 and the spinning is carried out by the
second spinning nozzle 53, and thus second fibers 131 are
accumulated onto the first support 110 to form the second support
130 (see FIG. 2C). The second support 130 is moved to the lower
portion of the second spray nozzle 54 and the spraying is carried
out by the second spray nozzle 54, and thus the droplets 141 of the
second ion exchange resin sprayed from the second spray nozzle 54
are applied to the second support 130 (see FIG. 2D).
[0050] Accordingly, the pores of the first and second supports 110
and 130 are filled with the droplets 121 and 141 of the first and
second ion-exchange resins, thereby realizing the fuel cell
separator.
[0051] The thicknesses t1 and t2 of the first and second supports
110 and 130 are preferably 1 .mu.m to 3 .mu.m. Since the
thicknesses t1 and t2 of the first and second supports 110 and 130
are of an ultra-thin structure, the droplets 121 and 141 of the
electrosprayed ion exchange resins may penetrate into the plurality
of pores of the first and second supports 110 and 130 to thus be
filled in the pores.
[0052] The thickness t1 of the first support 110 may be the same as
or different from the thickness t2 of the second support 130.
[0053] The fiber diameters of the first and second supports 110 and
130 are preferably in a range of 200 nm to 1.5 .mu.m, and more
preferably in a range of 500 nm to 1 .mu.m. The sizes of the first
and second pores of the first and second supports 110 and 130 are
preferably in a range of 0.2 .mu.m to 1.5 .mu.m.
[0054] Meanwhile, in some embodiments of the present invention, in
order to fill the droplets 121 and 141 of the ion exchange resins
in the plurality of pores of each of the first and second supports
110 and 130 without any gap, a spraying amount of the spraying
solution for forming the droplets 121 and 141 of the ion exchange
resins is set to be two to three times larger than a spinning
amount of the spinning solution for forming the first and second
supports 110 and 130.
[0055] The droplets 121 and 141 of the ion exchange resins sprayed
from the first and second spray nozzles 52 and 54 are evaporated to
vaporize the solvent from the moment the solvent is sprayed, and
when the vaporized solvent reaches the first and second supports
110 and 130, a larger amount of the solvent is vaporized in the
droplets 121 and 141 of the ion exchange resins.
[0056] FIGS. 4 and 5 are flowcharts of a method of manufacturing a
separator for a fuel cell according to second and third embodiments
of the present invention, respectively.
[0057] The methods of manufacturing a separator for a fuel cell
according to the second and third embodiments of the present
invention comprise forming a first support (S100), filling droplets
of an ion exchange resin into a plurality of first pores of a first
support (S110), forming a second support (S120), and filling the
plurality of second pores of the second support with droplets of
the ion exchange resin (S130), as in the first embodiment, and then
heat treating the first and second supports (S140) in the case of
the second embodiment as shown in FIG. 4, or thermal calendering
process (S150) in the case of the third embodiment as shown in FIG.
5.
[0058] Here, the heat applied to the first and second supports in
the heat treatment step (S140) or the thermal calendering step
(S150) causes the viscosity of the ion exchange resin filled in the
pores to be high, to thus remove the flowability of the ion
exchange resin to thereby fix the ion exchange resin inside the
plurality of pores of the first and second supports.
[0059] In the thermal calendering step (S150), the first and second
supports are fed into calender rolls to which heat is applied, but
the heat applied in the calender rolls has a temperature range that
does not melt the first and second supports and increases the
viscosity of the ion exchange resin, and the calender rolls have
roll intervals that do not block the pores by pressing the first
and second supports.
[0060] The fibers constituting the supports may be set to contain
20 wt % to 50 wt % of the fiber-forming polymer and 50 wt % to 80
wt % of the heat-resistant polymer. In this case, even if the heat
treatment is performed at a high temperature of 200.degree. C. to
230.degree. C., the deformation of the supports does not occur at
the heat treatment at the high temperature.
[0061] That is, even if the heat treatment process is performed at
a high temperature, by setting the polymer of the spinning solution
to contain 50 wt % to 80 wt % of the heat-resistant polymer and
thus raising the heat resistant temperatures of the first and
second supports prepared by electrospinning the spinning solution,
it is possible to prevent the deformation of the second supports
and increase the viscosity of the ion exchange resins filled in the
pores of the first and second supports by the high-temperature heat
treatment process to thus remove the flowability of the ion
exchange resins and fix the ion exchange resins in the pores,
thereby improving a filling rate of the ion exchange resins into
the pores of the first and second supports.
[0062] Here, when the polymer of the spinning solution contains
less than 50 wt % of the heat-resistant polymer, the content of the
heat-resistant polymer in the first and second supports is so small
that heat treatment at 200.degree. C. or higher is not nearly
possible. When the polymer of the spinning solution contains more
than 80 wt % of the heat-resistant polymer, it is difficult to spin
the spinning solution and is not easy to form fibers during
spinning.
[0063] Therefore, as in some embodiments of the present invention,
when the spinning solution containing 20 wt % to 50 wt % of the
fiber-forming polymer and 50 wt % to 80 wt % of the heat-resistant
polymer is electrospun, the spinning property may be improved, the
excellent fiber forming may be achieved, and the heat resistance
characteristic that the fiber can endure even when the heat
treatment is performed at 200.degree. C. or higher may be
increased.
[0064] The fiber-forming polymer may be any polymer capable of
obtaining fibers by electrospinning. Examples of the polymer
include polyvinylidene fluoride (PVdF), polymethyl methacrylate
(PMMA), and the like.
[0065] In some embodiments of the present invention, the
fiber-forming polymer may be replaced with an elastic polymer. In
this case, since the support is formed by accumulating fibers
containing the elastic polymer and the heat-resistant polymer, the
support that is not only deformed even at high-temperature heat
treatment, but is also elastic may be implemented. Here, the
elastic polymer is a polymer having properties that may be mixed
with the heat-resistant polymer.
[0066] The heat-resistant polymer resin may be any one selected
from the group consisting of aromatic polyesters including
polyamide, polyacrylonitrile (PAN), polyimide, polyamideimide, poly
(meta-phenylene isophthalamide), polysulfone, polyether ketone,
polyethylene terephthalate, polytrimethylene terephthalate, and
polyethylene naphthalate; polyphosphazenes including
polytetrafluoroethylene, polydiphenoxaphosphazenes, and poly {bis
[2-(2-methoxyethoxy) phosphazene]}; polyurethane copolymers
including polyurethane and polyether urethane; cellulose acetate;
cellulose acetate butyrate; cellulose acetate propionate; polyester
sulfone (PES); and polyether imide (PEI), and a combination
thereof.
[0067] In some embodiments of the present invention, it is possible
to prepare a spinning solution by mixing an elastic polymer and a
solvent, and then electrospin the spinning solution to obtain
fibers, to then accumulate the fibers to form first and second
supports having a plurality of pores. Polyurethane is a polymer
that is a heat-resistant polymer resin and has excellent
elasticity.
[0068] The first and second supports formed by accumulating the
fibers made of the elastic polymer in this way are excellent in
elasticity and may shrink and expand when the fuel cell is charged
and discharged. Therefore, there is an advantage that damage such
as tearing of the supports due to charging and discharging energy
may be prevented.
[0069] Referring to FIG. 6, an electrode assembly for a fuel cell
using a separator according to an embodiment of the present
invention includes: an anode 210 to which a fuel gas containing
hydrogen is supplied; a cathode 220 to which oxidant gas containing
oxygen is supplied; and a fuel cell separator 200 deployed between
the anode 210 and the cathode 220. Here, fibers containing a
fiber-forming polymer and a heat-resistant polymer are accumulated
to form a support having a plurality of pores, and an ion exchange
resin serves as an electrolyte for moving proton P toward the
cathode 220, in which the proton P is generated by the reaction of
the fuel gas supplied to the anode 210. The ion exchange resin is
filled into the pores of the support.
[0070] The anode 210 includes a catalyst layer 211 and a gas
diffusion layer 212. The catalyst layer 211 containing a catalyst
is in contact with and fixed to one side of the fuel cell separator
200, and the gas diffusion layer 212 is in contact with and fixed
to the catalyst layer 211. A fuel gas is supplied to the gas
diffusion layer 212 of the anode 210 and this fuel gas undergoes an
electrochemical reaction with the catalyst of the catalyst layer
211 to generate proton P. The generated proton P moves in the
cathode direction through the fuel cell separator 200.
[0071] The cathode 220 includes a catalyst layer 221 containing a
catalyst and a gas diffusion layer 222, which are sequentially
fixed to the other side of the fuel cell separator 200. An oxidant
gas is supplied to the gas diffusion layer 222 and the catalyst of
the catalyst layer 221 makes oxygen of the oxidant gas react with
proton moved through the fuel cell separator 200 to produce water
and electrons.
[0072] Therefore, an electric potential difference is generated
between the anode and the cathode due to a chemical reaction
between hydrogen and oxygen, so that current flows from the cathode
to the anode, thereby obtaining electric energy and generating
power.
[0073] In this case, an electrospinning process for forming a
support of a pore structure and an electrospraying process for
spraying droplets of an ion exchange resin into the pores to thus
fill the former into the latter, are alternately repeated to form a
multi-layer structure, thereby maximizing a filling rate of the ion
exchange resin.
[0074] When the filling rate of the ion exchange resin is improved
in the separator as described above, the ion exchange capacity is
improved, and the performance of moving proton (P) generated in the
anode 210 by a supply of a fuel gas toward the cathode 220 is
improved. As a result, the performance of the fuel cell may be
improved as the proton transferred through the separator 200 and
the oxygen of an oxidant gas supplied from the outside react with
each other quickly and effectively at the cathode 220.
[0075] The catalyst may react with the fuel gas and may apply any
material capable of making proton and oxygen react with each other
and may be made of one or more selected from the group consisting
of platinum (Pt), ruthenium (Ru), a platinum ruthenium alloy
(PtRu), palladium (Pd), rhodium (Rh), iridium (Ir), osmium (Os),
and gold (Au). In addition, the catalyst is supported on a carrier
and used. Carbon powder, activated carbon powder, graphite powder
and the like are used as the carrier. The carrier carrying the
catalyst may include a binder to maintain the adhesion between the
separator and the gas diffusion layer.
[0076] While the present invention has been particularly shown and
described with reference to exemplary embodiments thereof, by way
of illustration and example only, it is clearly understood that the
present invention is not to be construed as limiting the present
invention, and various changes and modifications may be made by
those skilled in the art within the protective scope of the
invention without departing off the spirit of the present
invention.
INDUSTRIAL APPLICABILITY
[0077] The present invention can be applied to a separator for a
fuel cell capable of realizing an ultra-thin structure, reducing a
manufacturing process, and preventing damage to a support by
charging and discharging energy. An electrospinning process for
forming a support of a pore structure and an electrospraying
process for spraying droplets of an ion exchange resin into the
pores to thus fill the former into the latter, are alternately
repeated to form a multi-layer structure, thereby maximizing a
filling rate of the ion exchange resin.
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