CA2266868A1 - Method of producing membrane electrode units for pem fuel cells - Google Patents
Method of producing membrane electrode units for pem fuel cells Download PDFInfo
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- CA2266868A1 CA2266868A1 CA002266868A CA2266868A CA2266868A1 CA 2266868 A1 CA2266868 A1 CA 2266868A1 CA 002266868 A CA002266868 A CA 002266868A CA 2266868 A CA2266868 A CA 2266868A CA 2266868 A1 CA2266868 A1 CA 2266868A1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8803—Supports for the deposition of the catalytic active composition
- H01M4/881—Electrolytic membranes
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
- C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
- C25B9/23—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms comprising ion-exchange membranes in or on which electrode material is embedded
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8825—Methods for deposition of the catalytic active composition
- H01M4/8842—Coating using a catalyst salt precursor in solution followed by evaporation and reduction of the precursor
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
- H01M4/8878—Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body
- H01M4/8882—Heat treatment, e.g. drying, baking
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
- H01M8/1004—Fuel cells with solid electrolytes characterised by membrane-electrode assemblies [MEA]
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0065—Solid electrolytes
- H01M2300/0082—Organic polymers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
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- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Manufacturing & Machinery (AREA)
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- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Fuel Cell (AREA)
- Inert Electrodes (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
Abstract
The invention concerns a method wherein membrane electrode units for fuel cells are produced in a continuous and automatable process. A web of polymer membrane is initially drawn through a bath containing a salt solution of the electrode material so that the web has a salt crust or film on both sides, and the salt adhering is then reduced in a stream of gas or in another bath.
Description
DEC.-23'98~WED) 10:33 HILL STEADMAN P.Oll F~ I L E~ P
r METE101~) FOR M~ ACT~l~IN G MP.lV~T-1R ~NE ~LECT~O~)E
~ITS (ME) [~Ol~ POLYl!~ ELEC rROLYTE ~JI~.l~RRA~E (PEM) FUEL ~,T~.T.T.~
Theinve ~ o~isd~ected ~c) a co~ ItiO,l~OUS ;~d ~llto1n~t~hle mettlod for man11~2~t1~ne M E (m~hraneelectrodl) UrUts forPE M fuel ce~ tha~ ~ cos~-b~n~iri1l ~nds~lit~hlPfor m ~sproducti~
I~ previously kno~n~ m~thn~c f 3 r m~mlf~1n~ nn~ elect~rod~s for fuel cells ~C), the desi~ed electrode m~teri~l is produced in a first methnfl step, this elect~ode nl~r~ bein~ applied ~nto th, ! electrolyte ar onco a carrier such as, for ~mr~e~ ca~hon paper ~n a fLl~her n ethod step. The applie~rion ca~ ensue by m Prh~nif ~ tnti~ or by appl~rir ~ a s~lsF~neinn (ink or paste) onto the membr~e a~d c~ se~llent evaporatio~ I If the solvent.
In ~itilnll to this n~hr~rl, whe~ ~in the electrode rn~t.A-ri~l must be m~mlf~rhlred ~d insulated in a first sta ,e before it ca~ be applied o~to the elect~olyte (polyIner me~l~ne) i~ a sec ~nd mPthn~ stage, there aIe also mPth~ w~erein the elec~rode m~pri~l ~s p~oduced directly on the electroly~e.
Tn~ ~ t~erein i., a Inethod wb~ rein t~e electrode m~tPn~l, for e ~ A pl~tin~l~, is rl~I ncitecl o~ the e ectrolyce from the ~apor phase. What is di~adv~nt~f.us ab~ut this mP~h~rl is ~ar it is also poorly sui~ed for a 2~ c~ ti~ f-~frre - due to ~e ~e luired e~ tinn p~ocess -- he~ ~se a mem~ne ~veb cannot be drawn ~hrou~ b a vacuu~ without l~ving the VlCUUm c~ pc~ Moreover, porous cat llyst layers arelliffi-~llt~o realize gi~en this n.~th~)d.
Another metllod is l~own whe~ ein th~ electrode ma~erial is prof~1~cerl 2 5 Ul situ on t_e me~brane. H. T;~k~n~k~ ~nd E. Torikai et al. cli~lr.~e this in Irlt. J. Hydrogen Erle~gy 7, 397 (1982). The ~embrane i~ thereby ~tretched be~een tWI) half cells, sntha~itsepar~ ;es the two ele~trolyte spaces of the half-cells f~om otle another. A salt ~ tio~ c)f ~he desired electrode m~tpri~
DEC. -23' 98~WED) 10:34 HILL STEADMAN P. 012 (fo~ e~cample, thus, an ~I2PtCl~ snI~ nn) is placed at the one side of ~he ~er~l~rane; d sllit~hl~ rç~ rtinn agellt is 1 Ilaced at the other side. The redtlc~ion age~t diffuses to t~e side of tlle Pt-coPtai ling solu~ion. The encouIlter of ~erell Irt-on agen~ with the PtCI6' ions the~ eby l~ads tO d precipitation of a pl~tirllIm layer in the susface region of tl~ e ~n~h~ne. T~is metho~l is fixed in time by the g~ven flif~Icinn rates of ~e rl ~t~nt~ Over ~d above ~his, this mP~hnfl must be ~pplied twice in order t~ prod~ce a rnmrlPt~ ~IE) since only o~e side of the Inembrane carl be coated i n o~e met~ad step.
IP view of the fu~ure si~lifir~-lr~ O f all fuel cells and, in parucular, of che PEM fuel ce~ls as energy converters o the fu~ure, there is tllus a need to offer an improved method for the autom Ited and cost-ben~fici~ rtl~e of the core of every PEM fuel cell, nanlel r the ME. It is t~e~efo~e an object of the present invention cn make a method .vailable ~Vit}l which ME for PEM
$uel cells can be . .~ -.L~red in a contiP llaus and ~tom~t~hlr p~ncess.
The general ~erception of t~e inv~ nti~n i that a~ ~.~t~ly ~ick salt c~ust or a salt film (rI~penclçnt on the amo unt of rern~ ing solvent) adhere tOthe nlembra~e web as ~ result of simply ~ i~pi~ t~e electrolyte m~ml~ranP web into a salt solutioP of the electrade mateI ial, and that, after ~nrtis ~nC~I~d, the electrode m~tPn~I ~dheres to rbe polymer i~ The desired o penetratioll depth a~d rnass.
Tlle çubject matter of t~e l ~ese~,lt i~vemion is a ~ethod fo~ the c~ntinl~n~ nllfar1 ~nes [sic~ of meml ~rane electrDde units for polymer-electroly~e memb~e (E)E~I) fuel cells, ~ here~ a poly~e~-electrolyte me~brane passing t~ough web-sh~ped 2 5 -- is drawn such ~hroug~ a solueion Df a sal~ of ~he elec~rode ~aterial in afi~st me~od ste~ *lat the ~alt ad~ e~es to both sides of the m~mhra~e in an amo~n~ adeq~ate for forIning :lle electrodes, and, ~e~, - t~e 9~ the ~embran~ is redu ed tO the electrc~d~ material iIl soIIltinn or ~ the gas stream irl a second ~ethod ste~.
DEC. -23' 98(WED) 10:34 HILL STEADMAN P. 013 In a~ adva~ltageo~ls development )f the invetltion, a drying s~ep for rP~oYing the solvent tllat adlleres to the membr~ne web is also iIlterp~sed bet~veen the ~wo mPtho~l steps.
~n prefer~ed emhoclime~t the secnnd mPthhd step, i.e. the r~t l~ir n of t~e ~ PrinE salts, is im~l~mpnted ~ the gas stre~ and, pote~ially, under telnperature elev~tion.
However, l~e emhnrli~Pnt is adv Lnrageous w~sein the membrane .weh is simply ~ nr~t~ rer ~lpflerrinn rolle ~ t~rough two baths, first tb.rough - one chat cr)nt~inc the sal~ d sllbse~Pn1 ly thr~ugh one ~at cnn~inc tbe 1~ rerll~rf;on a~ePt.
W~at are lcLr~d to as "~Pmhr~ne webs" or "electrolyte webs" ~r ~'polymer mem~ane webs" are all proces ;able webs of polyl~lers rhat con~tllrt ~rotons (or fnnr~ t hydroxide io~s ~s w ~11) rhat can be employ~ as electrolytes nf PEM f~el cells. Let sulfor ated poly~ty~l webs o~ Nafio~
(registe~ed t~ade~ark), ~vhich is a perfluc lidated polymer, be cited here by ~ray of e~rnrl~.
Botll the s~oo~h, proton-conduc ~g electrolyte ~embra~e as well as a membrane partially provided with car~i~ r m ten~l or cl~rrent çnll~ctors such as, f~r P~mrlP, carbon paper or fabric c ~ be eInployed in r~e inve~rive 2n m~thocl. GiveP~ the latter, the imme~sio I time of ~he me~brane ~h~nf~ctr~ n~lol~cly because the carrier m--~te~il 1 is ve~ pidly s~ ate~l with the salt sol~lri~
What are refe~ed to aS "elec~rodl m~ten~1" or "electro-catalyst'~ a~e the elec~odes sta~d~rd for PEMFC, parti~ arly precious me~ls such as, for 2 5 ~Ya~nl~lP~ pl~rin~l~n o~ ruthenium. Allo~ ~lectrodes ca~ be n~m~f~ red from co~ .y~ iingly mixed s~lt solutio~
~7hat are rcfe~red to as 'lsnlltticln of a ~ of electrode m~te~alll are salt ~ollltlnn.c of thc a~oremPntinned sub~tances and compour~.ds, i.e., for ~Y
the ~nlll~on of a ~ t~ s;llt witll Pt~ io~s such as a 2-molar sol~-tinn of DEC. -23' 98~WED) 10:34 HILL STEADMAN P. 014 hP~hIoropl~tin~te in ~vater. Of caurse, Pr~ r or arbitrary mixtures of metal salrs such as, for e~rnrI~, a ~ ure of Pt !~ salts wi~ll Ru3~ salcs for prnAIlrir~e P~JRu catalysts for ~e direc~-me~anol f~ el cell c~n be present. Neit~er the salt cited hero l~y ~y of ~ rIP nor s~uc metal or solvent are ~nterlded ta limit ~e scope c~f the inventiorl.
T~e salt cnnff..l,d~ioP prevailin~ he solution is, of course, ~lPpen~nt OII the desired thickn~cc or per etr.ltinn depth of the salt crust a~
well as on the ilrea that the elec~ode shou Ld occupy on the electrolyte web.
- The of~rnrqrinn of t~e ~embrane ~vith sal t can be corltrolled by the con~ t~"ion of the salt 5nllltinn In general, the web is pulled throu ~ the salt solution with a speed ~ O;
ho~v~., it i~ also possible rhat r~le web d wells in the salt soI~Itinn, i.e. rhat the ~nnrinllQU~ d aurom~t~ process rcpeatl dly prn~rides ho~ ne times. The pene~ration depth ~f the electrode materii 1 in the membri~e (depth distribution of l:he electr~-caralyst in the pnlymer elec~rolyte caIl be controlled via the dwell time of rhe membr~e in rh~ salt bath The prope~ies of the m~nlIfnftllre ~ ME can ~e varied i~ a ~road r~ge by ehe s~table 5t~ nn of ~he reaction c~Inrlitinnc (salt, re~ nn agent, ~olvent, thixotropy, viscosiey, pH value, n~cpntr~ nc~ bath aIld a~bient 2 o temperature) and ~y ~ litinr~ of addi~ves (fl~r ~Yam~1P. bi~de~s). T~is variatio~ is also rnccihI~ by ~nIhsequrn~ d~ ter-t~P~tn~nt of the n~p:~1 elec~rolyte polymer~e~ such a~ addi~g c lrre~t ~ oIl~cthr.~ (for ~mrI~, carbo fabnc), pressillg, imp~PgJl~tinn, tempen~, ar t~e like.
All st~ qr-1 rech~ti nn agents thal leave the membr~e n~ ~teri~ d the n~ cll~red ME .~n~ n~g~-l (specifieal] y i~ view of p~ nnin~), t~at can ~e removed 11~e free ~d ~hereb~r quami~ ativel~ reduce the adheri~g salt under op~ima~ly Inild ~nr~ t~ c are s~litahIP fc r the re~ tiQn of the s~t ~ nn~ to cml~ra~l:. F~r~mrl~s :~o~ for insr:~n ~, hydrogen or clj~
DEC. -2~' 981WED) 10:35 HILL STEADMAN P. 015 The inventian is described i~ grea er detail below on the basis of the t~vo Figures. The aforerrlentinn~f~ defir~t ~ons are valid rlot only far rhe ~p~rif~r~ion and cla~ms but also for the tl ImS employed in the PYF~I~ni~ri¢lr~ o~
the Figures.
5 Fi~u~e 1 shows t~e pl e~el ~d embod iment of the method wherein t~e occlIp~tinn of the m~m~r~I e web with salt e~sues in a bath A
and t~e ref~--ction of the ad lerirlg salt e~sues ~n a further ~ath B.
Figure 2 shows ~nc-th~r preferred en Lbodiment of the ill~entiorl wherein the membrane ~reb I.s first ~ pi~cl with salt in a bat~ A and the adhe~ng salt is then reduce ~ in t~e ~gas stream.
First, the polymer-elPctr~.Iyte mesnb~e ~reb 1 passillg rhroug~ web-like can be see~ ~ Fi~ure l. Via a fi~st de ~lecticn ~ol~er 2, the ~embra~e web proce~eds i~o the bath A in whieh the sal~ ~r the salt ~ixture is fou~d in illert solve~t, prefer~bly water or some 01 ~er solvellt wi~h a hig~ pctrir co~stant. Upon passage throllgh the bat~. A, the m~mhr~P is oco~piP~ with the salt fraIn Ihe snhltif~n on both sides, ~ nd a salt film or a salt cmst is on both sides af the web 1 w~erl the web 1 e ~erges from the l~alh A. The web 1 covered with salt is rn~ ct~l over the n, xt ~lefl~ tif~n roller 2 i~to the bat~ B
i~ ~vhich the rPrIuctinn age~ is C~ t~ ke~vise in a~ i~ert solvent. The salt 2 o adher~ng to the web 1 is thereby reduced whe~ passing t~rau~h the bath B.
~ia the la~t deflectian rolle~ 2 at t~e extn ~e right end of ~ re l, the web 1 proceeds ~s finis~ed ME in~o furt~er pro :essi~g such as, far e~ p~, illtO a ~uttirlg m Irhin~ Later, ~he eleclrode s~r Icn~re ca~ be opti~ni7.~ with a press, potentially with follo~in~ thermal t~edtl ~ent.
2 5 E;igure ~ likewise shows a ~eb of poly~ner-electroly~e membra~e 1 passin~ ~hrough ~N~b-likc that is stec~cd ~ efl~ctlnn rnlle~ 2 inta, firs~. rhe bath A thal, as in Figure 1, contains the ,alt of the elec~rode material in DEC.-23'98~WED) 10:35 HILL STEADMAN P.016 soluuan. Upon passage t~rough the L~atll A, a s~lt crust forms on the membrane web, and, after leaving ~he bath A, the encn~sted me~ane web is pulled thr~ugh a vessel 3 with reclucing at nosphere th~t potentially has a h~t.~g device av_ilable to it. Gia~eous rec uction agent ca~ fla~r mw the vessel:~ with re~ ine ;~tTnr~sphf~rp via the ad~is lon npenin~ 4. When it emer~ es from the vessel ~, both sides of the memb a~le web are again coated ~vith electrode r~t~
In the em~ndimptlt ~vhere~n the re l~lction of the salt cmst on the memb~ane web ensues in the gas stre~ is advantageous th;at tlle mi~ing of 0 ~he contenes of both ba~hs i.5 avoided in bi th B. In che embnrlimpnt acco.. ~lg to Fi~ure l, ho~vever, this cdn also be achi ~ved in that a drying n~prhqnicln such as, forPY~mrl~, a ventilato~ or farl t~ ~r [. .] at the level ~f the ~ pctinn roller 2 that dries the ~eb from both side! ~nd rids rhe salt cmst of ~olvent ixi~terposed ~etween rhe eme~gerlce from t le bath A and the en~ry of the ITIPmbr7lnp web i~to the h~th B.
The in~entive methad is clistin~ hed in that both sides of the memb~e c~ be s;~nult~np~ usly coverec ~it~ an electroch~ y active eleet~ode layer in a ~ ntin~ c prc~cess an d, thus, ~n ME a~ses in a sin~le pro~sstep. ~li~ m~n~1f~nl~n~ speeds ~iven lo~v costs can thu~ be achiev~d by the elimin~ti~n of ~ic~onn~l~ous wor~:steps ~ we~ as t~ne~ ni~g~
diffusiDn-limited steps.
, . , .. . . , . , ~
r METE101~) FOR M~ ACT~l~IN G MP.lV~T-1R ~NE ~LECT~O~)E
~ITS (ME) [~Ol~ POLYl!~ ELEC rROLYTE ~JI~.l~RRA~E (PEM) FUEL ~,T~.T.T.~
Theinve ~ o~isd~ected ~c) a co~ ItiO,l~OUS ;~d ~llto1n~t~hle mettlod for man11~2~t1~ne M E (m~hraneelectrodl) UrUts forPE M fuel ce~ tha~ ~ cos~-b~n~iri1l ~nds~lit~hlPfor m ~sproducti~
I~ previously kno~n~ m~thn~c f 3 r m~mlf~1n~ nn~ elect~rod~s for fuel cells ~C), the desi~ed electrode m~teri~l is produced in a first methnfl step, this elect~ode nl~r~ bein~ applied ~nto th, ! electrolyte ar onco a carrier such as, for ~mr~e~ ca~hon paper ~n a fLl~her n ethod step. The applie~rion ca~ ensue by m Prh~nif ~ tnti~ or by appl~rir ~ a s~lsF~neinn (ink or paste) onto the membr~e a~d c~ se~llent evaporatio~ I If the solvent.
In ~itilnll to this n~hr~rl, whe~ ~in the electrode rn~t.A-ri~l must be m~mlf~rhlred ~d insulated in a first sta ,e before it ca~ be applied o~to the elect~olyte (polyIner me~l~ne) i~ a sec ~nd mPthn~ stage, there aIe also mPth~ w~erein the elec~rode m~pri~l ~s p~oduced directly on the electroly~e.
Tn~ ~ t~erein i., a Inethod wb~ rein t~e electrode m~tPn~l, for e ~ A pl~tin~l~, is rl~I ncitecl o~ the e ectrolyce from the ~apor phase. What is di~adv~nt~f.us ab~ut this mP~h~rl is ~ar it is also poorly sui~ed for a 2~ c~ ti~ f-~frre - due to ~e ~e luired e~ tinn p~ocess -- he~ ~se a mem~ne ~veb cannot be drawn ~hrou~ b a vacuu~ without l~ving the VlCUUm c~ pc~ Moreover, porous cat llyst layers arelliffi-~llt~o realize gi~en this n.~th~)d.
Another metllod is l~own whe~ ein th~ electrode ma~erial is prof~1~cerl 2 5 Ul situ on t_e me~brane. H. T;~k~n~k~ ~nd E. Torikai et al. cli~lr.~e this in Irlt. J. Hydrogen Erle~gy 7, 397 (1982). The ~embrane i~ thereby ~tretched be~een tWI) half cells, sntha~itsepar~ ;es the two ele~trolyte spaces of the half-cells f~om otle another. A salt ~ tio~ c)f ~he desired electrode m~tpri~
DEC. -23' 98~WED) 10:34 HILL STEADMAN P. 012 (fo~ e~cample, thus, an ~I2PtCl~ snI~ nn) is placed at the one side of ~he ~er~l~rane; d sllit~hl~ rç~ rtinn agellt is 1 Ilaced at the other side. The redtlc~ion age~t diffuses to t~e side of tlle Pt-coPtai ling solu~ion. The encouIlter of ~erell Irt-on agen~ with the PtCI6' ions the~ eby l~ads tO d precipitation of a pl~tirllIm layer in the susface region of tl~ e ~n~h~ne. T~is metho~l is fixed in time by the g~ven flif~Icinn rates of ~e rl ~t~nt~ Over ~d above ~his, this mP~hnfl must be ~pplied twice in order t~ prod~ce a rnmrlPt~ ~IE) since only o~e side of the Inembrane carl be coated i n o~e met~ad step.
IP view of the fu~ure si~lifir~-lr~ O f all fuel cells and, in parucular, of che PEM fuel ce~ls as energy converters o the fu~ure, there is tllus a need to offer an improved method for the autom Ited and cost-ben~fici~ rtl~e of the core of every PEM fuel cell, nanlel r the ME. It is t~e~efo~e an object of the present invention cn make a method .vailable ~Vit}l which ME for PEM
$uel cells can be . .~ -.L~red in a contiP llaus and ~tom~t~hlr p~ncess.
The general ~erception of t~e inv~ nti~n i that a~ ~.~t~ly ~ick salt c~ust or a salt film (rI~penclçnt on the amo unt of rern~ ing solvent) adhere tOthe nlembra~e web as ~ result of simply ~ i~pi~ t~e electrolyte m~ml~ranP web into a salt solutioP of the electrade mateI ial, and that, after ~nrtis ~nC~I~d, the electrode m~tPn~I ~dheres to rbe polymer i~ The desired o penetratioll depth a~d rnass.
Tlle çubject matter of t~e l ~ese~,lt i~vemion is a ~ethod fo~ the c~ntinl~n~ nllfar1 ~nes [sic~ of meml ~rane electrDde units for polymer-electroly~e memb~e (E)E~I) fuel cells, ~ here~ a poly~e~-electrolyte me~brane passing t~ough web-sh~ped 2 5 -- is drawn such ~hroug~ a solueion Df a sal~ of ~he elec~rode ~aterial in afi~st me~od ste~ *lat the ~alt ad~ e~es to both sides of the m~mhra~e in an amo~n~ adeq~ate for forIning :lle electrodes, and, ~e~, - t~e 9~ the ~embran~ is redu ed tO the electrc~d~ material iIl soIIltinn or ~ the gas stream irl a second ~ethod ste~.
DEC. -23' 98(WED) 10:34 HILL STEADMAN P. 013 In a~ adva~ltageo~ls development )f the invetltion, a drying s~ep for rP~oYing the solvent tllat adlleres to the membr~ne web is also iIlterp~sed bet~veen the ~wo mPtho~l steps.
~n prefer~ed emhoclime~t the secnnd mPthhd step, i.e. the r~t l~ir n of t~e ~ PrinE salts, is im~l~mpnted ~ the gas stre~ and, pote~ially, under telnperature elev~tion.
However, l~e emhnrli~Pnt is adv Lnrageous w~sein the membrane .weh is simply ~ nr~t~ rer ~lpflerrinn rolle ~ t~rough two baths, first tb.rough - one chat cr)nt~inc the sal~ d sllbse~Pn1 ly thr~ugh one ~at cnn~inc tbe 1~ rerll~rf;on a~ePt.
W~at are lcLr~d to as "~Pmhr~ne webs" or "electrolyte webs" ~r ~'polymer mem~ane webs" are all proces ;able webs of polyl~lers rhat con~tllrt ~rotons (or fnnr~ t hydroxide io~s ~s w ~11) rhat can be employ~ as electrolytes nf PEM f~el cells. Let sulfor ated poly~ty~l webs o~ Nafio~
(registe~ed t~ade~ark), ~vhich is a perfluc lidated polymer, be cited here by ~ray of e~rnrl~.
Botll the s~oo~h, proton-conduc ~g electrolyte ~embra~e as well as a membrane partially provided with car~i~ r m ten~l or cl~rrent çnll~ctors such as, f~r P~mrlP, carbon paper or fabric c ~ be eInployed in r~e inve~rive 2n m~thocl. GiveP~ the latter, the imme~sio I time of ~he me~brane ~h~nf~ctr~ n~lol~cly because the carrier m--~te~il 1 is ve~ pidly s~ ate~l with the salt sol~lri~
What are refe~ed to aS "elec~rodl m~ten~1" or "electro-catalyst'~ a~e the elec~odes sta~d~rd for PEMFC, parti~ arly precious me~ls such as, for 2 5 ~Ya~nl~lP~ pl~rin~l~n o~ ruthenium. Allo~ ~lectrodes ca~ be n~m~f~ red from co~ .y~ iingly mixed s~lt solutio~
~7hat are rcfe~red to as 'lsnlltticln of a ~ of electrode m~te~alll are salt ~ollltlnn.c of thc a~oremPntinned sub~tances and compour~.ds, i.e., for ~Y
the ~nlll~on of a ~ t~ s;llt witll Pt~ io~s such as a 2-molar sol~-tinn of DEC. -23' 98~WED) 10:34 HILL STEADMAN P. 014 hP~hIoropl~tin~te in ~vater. Of caurse, Pr~ r or arbitrary mixtures of metal salrs such as, for e~rnrI~, a ~ ure of Pt !~ salts wi~ll Ru3~ salcs for prnAIlrir~e P~JRu catalysts for ~e direc~-me~anol f~ el cell c~n be present. Neit~er the salt cited hero l~y ~y of ~ rIP nor s~uc metal or solvent are ~nterlded ta limit ~e scope c~f the inventiorl.
T~e salt cnnff..l,d~ioP prevailin~ he solution is, of course, ~lPpen~nt OII the desired thickn~cc or per etr.ltinn depth of the salt crust a~
well as on the ilrea that the elec~ode shou Ld occupy on the electrolyte web.
- The of~rnrqrinn of t~e ~embrane ~vith sal t can be corltrolled by the con~ t~"ion of the salt 5nllltinn In general, the web is pulled throu ~ the salt solution with a speed ~ O;
ho~v~., it i~ also possible rhat r~le web d wells in the salt soI~Itinn, i.e. rhat the ~nnrinllQU~ d aurom~t~ process rcpeatl dly prn~rides ho~ ne times. The pene~ration depth ~f the electrode materii 1 in the membri~e (depth distribution of l:he electr~-caralyst in the pnlymer elec~rolyte caIl be controlled via the dwell time of rhe membr~e in rh~ salt bath The prope~ies of the m~nlIfnftllre ~ ME can ~e varied i~ a ~road r~ge by ehe s~table 5t~ nn of ~he reaction c~Inrlitinnc (salt, re~ nn agent, ~olvent, thixotropy, viscosiey, pH value, n~cpntr~ nc~ bath aIld a~bient 2 o temperature) and ~y ~ litinr~ of addi~ves (fl~r ~Yam~1P. bi~de~s). T~is variatio~ is also rnccihI~ by ~nIhsequrn~ d~ ter-t~P~tn~nt of the n~p:~1 elec~rolyte polymer~e~ such a~ addi~g c lrre~t ~ oIl~cthr.~ (for ~mrI~, carbo fabnc), pressillg, imp~PgJl~tinn, tempen~, ar t~e like.
All st~ qr-1 rech~ti nn agents thal leave the membr~e n~ ~teri~ d the n~ cll~red ME .~n~ n~g~-l (specifieal] y i~ view of p~ nnin~), t~at can ~e removed 11~e free ~d ~hereb~r quami~ ativel~ reduce the adheri~g salt under op~ima~ly Inild ~nr~ t~ c are s~litahIP fc r the re~ tiQn of the s~t ~ nn~ to cml~ra~l:. F~r~mrl~s :~o~ for insr:~n ~, hydrogen or clj~
DEC. -2~' 981WED) 10:35 HILL STEADMAN P. 015 The inventian is described i~ grea er detail below on the basis of the t~vo Figures. The aforerrlentinn~f~ defir~t ~ons are valid rlot only far rhe ~p~rif~r~ion and cla~ms but also for the tl ImS employed in the PYF~I~ni~ri¢lr~ o~
the Figures.
5 Fi~u~e 1 shows t~e pl e~el ~d embod iment of the method wherein t~e occlIp~tinn of the m~m~r~I e web with salt e~sues in a bath A
and t~e ref~--ction of the ad lerirlg salt e~sues ~n a further ~ath B.
Figure 2 shows ~nc-th~r preferred en Lbodiment of the ill~entiorl wherein the membrane ~reb I.s first ~ pi~cl with salt in a bat~ A and the adhe~ng salt is then reduce ~ in t~e ~gas stream.
First, the polymer-elPctr~.Iyte mesnb~e ~reb 1 passillg rhroug~ web-like can be see~ ~ Fi~ure l. Via a fi~st de ~lecticn ~ol~er 2, the ~embra~e web proce~eds i~o the bath A in whieh the sal~ ~r the salt ~ixture is fou~d in illert solve~t, prefer~bly water or some 01 ~er solvellt wi~h a hig~ pctrir co~stant. Upon passage throllgh the bat~. A, the m~mhr~P is oco~piP~ with the salt fraIn Ihe snhltif~n on both sides, ~ nd a salt film or a salt cmst is on both sides af the web 1 w~erl the web 1 e ~erges from the l~alh A. The web 1 covered with salt is rn~ ct~l over the n, xt ~lefl~ tif~n roller 2 i~to the bat~ B
i~ ~vhich the rPrIuctinn age~ is C~ t~ ke~vise in a~ i~ert solvent. The salt 2 o adher~ng to the web 1 is thereby reduced whe~ passing t~rau~h the bath B.
~ia the la~t deflectian rolle~ 2 at t~e extn ~e right end of ~ re l, the web 1 proceeds ~s finis~ed ME in~o furt~er pro :essi~g such as, far e~ p~, illtO a ~uttirlg m Irhin~ Later, ~he eleclrode s~r Icn~re ca~ be opti~ni7.~ with a press, potentially with follo~in~ thermal t~edtl ~ent.
2 5 E;igure ~ likewise shows a ~eb of poly~ner-electroly~e membra~e 1 passin~ ~hrough ~N~b-likc that is stec~cd ~ efl~ctlnn rnlle~ 2 inta, firs~. rhe bath A thal, as in Figure 1, contains the ,alt of the elec~rode material in DEC.-23'98~WED) 10:35 HILL STEADMAN P.016 soluuan. Upon passage t~rough the L~atll A, a s~lt crust forms on the membrane web, and, after leaving ~he bath A, the encn~sted me~ane web is pulled thr~ugh a vessel 3 with reclucing at nosphere th~t potentially has a h~t.~g device av_ilable to it. Gia~eous rec uction agent ca~ fla~r mw the vessel:~ with re~ ine ;~tTnr~sphf~rp via the ad~is lon npenin~ 4. When it emer~ es from the vessel ~, both sides of the memb a~le web are again coated ~vith electrode r~t~
In the em~ndimptlt ~vhere~n the re l~lction of the salt cmst on the memb~ane web ensues in the gas stre~ is advantageous th;at tlle mi~ing of 0 ~he contenes of both ba~hs i.5 avoided in bi th B. In che embnrlimpnt acco.. ~lg to Fi~ure l, ho~vever, this cdn also be achi ~ved in that a drying n~prhqnicln such as, forPY~mrl~, a ventilato~ or farl t~ ~r [. .] at the level ~f the ~ pctinn roller 2 that dries the ~eb from both side! ~nd rids rhe salt cmst of ~olvent ixi~terposed ~etween rhe eme~gerlce from t le bath A and the en~ry of the ITIPmbr7lnp web i~to the h~th B.
The in~entive methad is clistin~ hed in that both sides of the memb~e c~ be s;~nult~np~ usly coverec ~it~ an electroch~ y active eleet~ode layer in a ~ ntin~ c prc~cess an d, thus, ~n ME a~ses in a sin~le pro~sstep. ~li~ m~n~1f~nl~n~ speeds ~iven lo~v costs can thu~ be achiev~d by the elimin~ti~n of ~ic~onn~l~ous wor~:steps ~ we~ as t~ne~ ni~g~
diffusiDn-limited steps.
, . , .. . . , . , ~
Claims (5)
1. Method for the continuous manufacture of membrane electrode units (ME) for polymer-electrolyte membrane (PEM) fuel cells, whereby a polymer-electrolyte membrane (membrane web) passing through web-shaped - is drawn such through a solution of a salt of the electrode material in a first method step that the salt adheres to both sides of the membrane in an amount adequate for forming the electrodes, and, then, - the salt on the membrane is reduce in a second method step.
2. Method according to claim 1, whereby the membrane web is pulled through a bath with a solution of the reduction agent or with the fluid reduction agent in the second method steps.
3. Method according to claim 1, whereby the membrane web is pulled through a vessel with reducing atmosphere in the second method step.
4. Method according to one of the preceding claims, whereby a drying step for the removal of the solvent on the membrane web is interposed between the two method steps.
5. Method according to one of the preceding claims 1, 3 or 4, whereby the reduction of the salt adhering to the web occurs in the gas stream and upon temperature elevation.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19625614.3 | 1996-06-26 | ||
| DE19625614 | 1996-06-26 | ||
| PCT/DE1997/001322 WO1997050142A1 (en) | 1996-06-26 | 1997-06-25 | Method of producing membrane electrode units for pem fuel cells |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2266868A1 true CA2266868A1 (en) | 1997-12-31 |
Family
ID=7798096
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002266868A Abandoned CA2266868A1 (en) | 1996-06-26 | 1997-06-25 | Method of producing membrane electrode units for pem fuel cells |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0907980B1 (en) |
| JP (1) | JP2000512798A (en) |
| AT (1) | ATE191101T1 (en) |
| CA (1) | CA2266868A1 (en) |
| DE (1) | DE59701326D1 (en) |
| DK (1) | DK0907980T3 (en) |
| ES (1) | ES2145618T3 (en) |
| NO (1) | NO986065L (en) |
| WO (1) | WO1997050142A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10050467A1 (en) | 2000-10-12 | 2002-05-16 | Omg Ag & Co Kg | Method for producing a membrane electrode assembly for fuel cells |
| DE10124272A1 (en) * | 2001-05-18 | 2002-11-21 | Daimler Chrysler Ag | Continuous production of polymer electrolyte membrane-electrode array for fuel cell involves coating or impregnating and drying substrate, producing and drying polymer electrolyte membrane in parallel stage and lamination |
| DE10159476A1 (en) | 2001-12-04 | 2003-07-17 | Omg Ag & Co Kg | Process for the manufacture of membrane electrode assemblies for fuel cells |
| DE102020109690A1 (en) | 2020-04-07 | 2021-10-07 | Deutsches Zentrum für Luft- und Raumfahrt e.V. | Selective modification of ion exchange membranes with iridium oxide by pH-controlled precipitation of IrOx species at the phase boundary |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3267017A (en) * | 1962-01-31 | 1966-08-16 | Ibm | Apparatus for producing magnetic recording materials |
| GB1013703A (en) * | 1962-09-20 | 1965-12-22 | Commw Scient Ind Res Org | Improvements relating to fuel cells |
| LU53772A1 (en) * | 1967-05-30 | 1969-03-20 | ||
| GB1360824A (en) * | 1971-06-30 | 1974-07-24 | Cottbus Textilkombinat | Metallisation process for inorganic and organic polymers |
| DE2647108A1 (en) * | 1976-10-19 | 1978-04-20 | Felten & Guilleaume Carlswerk | Continuous metallising of glass fibre - using four bath system for pretreatment, silvering and copper coating with intermediate washes |
| JPS5723080A (en) * | 1980-07-16 | 1982-02-06 | Tokuyama Soda Co Ltd | Preparation of ion exchange membrane-electrode catalyst layer bonded body |
| JPS5754288A (en) * | 1980-09-17 | 1982-03-31 | Tokuyama Soda Co Ltd | Preparation of ion exchange membrane-electrode catalyst layer conjugate |
| JPS6026497B2 (en) * | 1981-11-11 | 1985-06-24 | 東ソー株式会社 | Manufacturing method of cation exchange membrane |
| JPS58151466A (en) * | 1982-03-04 | 1983-09-08 | Canon Inc | Method for plating beltlike film |
| JPS58176222A (en) * | 1982-04-12 | 1983-10-15 | Toyo Soda Mfg Co Ltd | Fixation of metal on cation exchange membrane |
| JPS58181882A (en) * | 1982-04-14 | 1983-10-24 | Toyo Soda Mfg Co Ltd | Method for fixedly depositing metal on surface of cation exchange membrane |
| US4959132A (en) * | 1988-05-18 | 1990-09-25 | North Carolina State University | Preparing in situ electrocatalytic films in solid polymer electrolyte membranes, composite microelectrode structures produced thereby and chloralkali process utilizing the same |
| US4988582A (en) * | 1990-05-04 | 1991-01-29 | Bell Communications Research, Inc. | Compact fuel cell and continuous process for making the cell |
-
1997
- 1997-06-25 ES ES97932710T patent/ES2145618T3/en not_active Expired - Lifetime
- 1997-06-25 WO PCT/DE1997/001322 patent/WO1997050142A1/en active IP Right Grant
- 1997-06-25 EP EP97932710A patent/EP0907980B1/en not_active Expired - Lifetime
- 1997-06-25 DK DK97932710T patent/DK0907980T3/en active
- 1997-06-25 AT AT97932710T patent/ATE191101T1/en not_active IP Right Cessation
- 1997-06-25 DE DE59701326T patent/DE59701326D1/en not_active Expired - Fee Related
- 1997-06-25 JP JP10502111A patent/JP2000512798A/en active Pending
- 1997-06-25 CA CA002266868A patent/CA2266868A1/en not_active Abandoned
-
1998
- 1998-12-22 NO NO986065A patent/NO986065L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0907980B1 (en) | 2000-03-22 |
| WO1997050142A1 (en) | 1997-12-31 |
| DK0907980T3 (en) | 2000-08-21 |
| DE59701326D1 (en) | 2000-04-27 |
| NO986065D0 (en) | 1998-12-22 |
| JP2000512798A (en) | 2000-09-26 |
| ATE191101T1 (en) | 2000-04-15 |
| ES2145618T3 (en) | 2000-07-01 |
| EP0907980A1 (en) | 1999-04-14 |
| NO986065L (en) | 1999-02-17 |
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