CA2467311A1 - Fuel cell - Google Patents
Fuel cell Download PDFInfo
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- CA2467311A1 CA2467311A1 CA002467311A CA2467311A CA2467311A1 CA 2467311 A1 CA2467311 A1 CA 2467311A1 CA 002467311 A CA002467311 A CA 002467311A CA 2467311 A CA2467311 A CA 2467311A CA 2467311 A1 CA2467311 A1 CA 2467311A1
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- Canada
- Prior art keywords
- fuel
- fuel cell
- anode
- carbon
- cell according
- Prior art date
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Classifications
-
- 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
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0234—Carbonaceous material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L23/00—Flanged joints
- F16L23/02—Flanged joints the flanges being connected by members tensioned axially
- F16L23/032—Flanged joints the flanges being connected by members tensioned axially characterised by the shape or composition of the flanges
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L23/00—Flanged joints
- F16L23/02—Flanged joints the flanges being connected by members tensioned axially
- F16L23/024—Flanged joints the flanges being connected by members tensioned axially characterised by how the flanges are joined to, or form an extension of, the pipes
-
- 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
- H01M4/8605—Porous electrodes
-
- 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
- H01M4/8807—Gas diffusion layers
-
- 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
- H01M4/8817—Treatment of supports before application of the catalytic active composition
-
- 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
- H01M8/1009—Fuel cells with solid electrolytes with one of the reactants being liquid, solid or liquid-charged
-
- 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
- H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
- H01M8/2455—Grouping of fuel cells, e.g. stacking of fuel cells with liquid, solid or electrolyte-charged reactants
-
- 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
- H01M4/90—Selection of catalytic material
- H01M4/92—Metals of platinum group
- H01M4/921—Alloys or mixtures with metallic elements
-
- 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 & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Electrochemistry (AREA)
- Manufacturing & Machinery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Composite Materials (AREA)
- Inert Electrodes (AREA)
- Fuel Cell (AREA)
Abstract
An object of the present invention is to provide a fuel cell capable of improving an output by reducing concentration polarization of a liquid fuel in an anode.
The fuel cell comprises an anode and a cathode on both surfaces of an electrolyte membrane, supplies the liquid fuel to the anode, supplies an oxidant gas to the cathode, to react the liquid fuel with the oxidant gas and to generate power, wherein the anode comprises a gas diffusion layer constituted by filling a conductive porous support which is coated with a hydrophilic material with a conductive powder, and a catalyst layer.
The fuel cell comprises an anode and a cathode on both surfaces of an electrolyte membrane, supplies the liquid fuel to the anode, supplies an oxidant gas to the cathode, to react the liquid fuel with the oxidant gas and to generate power, wherein the anode comprises a gas diffusion layer constituted by filling a conductive porous support which is coated with a hydrophilic material with a conductive powder, and a catalyst layer.
Description
SPECIFTCATSt~N
f7CTLE OF THE INVBNTTR~N
FUEL CELT.
BprCICC's1t01'J~?F~ OF THE TNV~:NTIt7N
The present invention acetates to a fuel cell which directly r$ae3.~r~ss a liquia9. fuel to generate poster.
The foal cell takes out chemical enea~gx which a fuel (hydrogen or the li3Ge) has directly as electric energy by electrode reactircen. and is a power gemeratioa system which has almost no adv~srse ir~fluence az:~ an envircrnrnent because a reaction product is only v~ater in principle.
CQnventiunally, a hydrogen-rich g~xs which is a reformation ~sf s source gas has been used as the fu~sl. In such a case.
~.5 heawever, a refaxmsr m~s~t be clisposecl in the pow$r generation system, c~ceating a $roblam of an enlarged device. 2'hus, 3n order to solve the prrrblem of ~~ievice enlargement , s. fuel cell Iaas be~e~n de~trelmpc~d which d~.rectly receives a liquid fuel to generates power .
In the conventional direst liquid fuel type fuel cell wh3.ch uses a liquid as the fuel, ~c~r examgle~. a call xs constituted by making ~, solid polyme~r~.c c~ta.c~n exchanger an electrolyte metnbxsne, and holding bot;km. s~~.c3.es of the elststxaly'G~a membrano between n anode rind a cathode . The anode has a lam~.nated structure of a gay; diffusion layer Constituted of woven car unwav~sn cloth nna~de of carbon fibers and, a platinum and ruthenium c~antaining ca,tal~st layer -d3.spased thereon. A liquid fuel such as methanol or dunethyl ether ( D) ~.s supplied to the axaade , while s.~.z~ s~s supplied as an oxidant to the cathode.
°~hus, electrochemical axidetion reaction of the liquid fuel c~ocurs in the cata~.yst 1ay$r of the anode to gen$rate ,a pratan ~ I~+ ) . The pratan movers through the . slecfirolyte rn$mbrane to reach the cathode. At th3.s ~t~.me, an electron ~.s taken out to $n externaX cirGUi'G to. be used as electric energy. Cn the other hand., in the cathode, the iQ proton moved through the eleetralyte memEbrane reacts w3.th oxygen in air to generate Water. Further. ~.n the anode:
carbora d~.oxide is r,~er~erated as a main pr~r~dumt . and discharged to the outside s~f the cell system.
Here, according tc~ the fuel ce~.l, 3.n ardar to ~srncsottsly supply the liquid fuel a.n the anode, a pox~r~u~s rnc~t~ar~.al of the gas diffusion layer sss . made of carbon paper treated;.by palyfluoroethylene ~~,bers to .improve wtttesr .
re~pe~.~.ency (see PCT National PubliG,~t~.on No. 11-51~D3~.~1~.
la:LG . 5 is an es~panded view of a carbon fiber on a ZO liquid fuel supply side of a gas diffusion l~.ayer. ~n the drawing, a reference numeral. 101 denotes a c~bon fiber of a porous material which aonstitutes the 13.c~u~.d fuel su~xply side, and a refez~ence numeral 102 denotes an aperture ~ormec~, bstweeri the caxban fibers 101. A. reference numeral 103 dez~vtes methanol which is the liquid. fuel. suQplied to the gas d,3.ffusiexa layer o~ an anode side .
However, in the aforementioned C~c~nventiona~. ~ue1 _.
cell , because of th~a water repell~ency o~i: the. porous material used far' the nod~, as shown in FYI. 5. it 3.s d~.~f~.~cu3.t for the methanol 103 which is the liquid fuel to persne~tte the carbon fiber ~.~7~. of the porr~t~s mat~rial.
Consequently', a r~duction occuxs ~,n permeab3.3.3.ty of the methanol inta the anodes. Therefore, suifia~.ent supplying of the methanol which is the ~.lf~Lll.d ~lyrB~_ to the cats,~.yst layer' of the anode is impossible, causing a problem of an increase in coz~.cerrtxation polarization of the methanol in ~ the anode.
' SUMMA3LtY Cl=' T~I~ TNVBHTION
' . Aa ab jest of the ~rresent iavent~.on is to provide a fuel sell capab7.e of imprav~.ng an output: . by reducing .
concentration polarisation of a li~u~.d ~'xel a.n an anode.
A ' fa.~cs~'C aspect of the present irrveation is .. . dir~ecte~d to a fuesl ce~.l which comp~Cise~s an ~ anode and a c$thode an both surfaces o~ an.ele~strolyte membrane, suppliers a liquid fuel to the anode, supplies au o~idaaxt g8i.5s to the cathode, to react tht~ ~ liquid fuel with the oxidant gas and to gr~nerate power, whare,in the x~rrade comprises a~. ga.s d3.f~u$ion Zayer constituted by fi.lllt~g a conductive porous ~auppor't 9ohich is coated w~.th a hydrophilic material w3.th a conductive powder, and a 2S catalyst layer.
A second a$pe~cst of the pr~saer~t ~.nvention 3,.s directed to the above ~txel ce~.~., wherein the porous support .. 4 -3s made of caxbon f3.bers .
A third aspect of the present in~,r~snt~.on is dixectad to the above ttxel ~$1,~., wherein, the gas diffusion layer Qontains 5 t~at% to 64 vvt% of th~x hydxt~~rhilic material with respect td a sum total of the conductive porous support arid th~a hydrophilic matexial.
A fnurth aspect of the present j.nverit~.on ~.s di.reoted.to the above fuel tsell, where~.n. the, gas diffuse~.on ~.ayer contains ~t~ ~vt% to 4Q wt% o~ the hyc9xophilic material Zo with resspeCt to a earn total. of the conductive pox~c~txs support a.nr~. the hydrophilic material.
A fifth aspect of the present irment~.on; is directed to the above fuel cell, wherein tlxe .Conductive powder is . carbon b.~.aCk.
1~ . A s3~.xth aspect of the p5ce~seat invention is directed to the above fuel ce7.l, wherein a water-repellent tnxtter~.al. is added to the carbon blank.
A seventh aspect ref the present invent5.on is dires3ted to the above fuel cell, wherein. S ~rt% to 80 wt% of 20 the wat~xr-repellent material with respect to the sum ~COtal of the conductive porous support axxd they grater-repellent mtaterisl is added tc~ the caxbon blscsk.
An eighth aspect o~ thp pr~s~teat invention is directed to the t~bove fuel ae~,~., wherein 20 wt% to 4~1 wt%
a5 of the vrate~r-repel~.ent ms,terial with respect tc~ the suns tt5t~ea. of the oonductivr~s poxous stapport acrd tY~e v~atesr_ repellent matex~.a~, is added to the carbon blacx.
_ r,~ _ A niz~th aspect of the present inventa.on ass directed to the abovr~ fuel cell, wherein a, dibutylphthalate absorption of the carbon blaol~c is 160 ml./~,Ot~ g or more.
A tenth aspect o~ the pre~g$nt in trention is d~.xected tc~ the above fuel dell, wherein a. dibutylphthalate absorption of the dar'boa black is 36e m~./ ~.01~ g wr more .
An eleventh aspect of the pr~sser~t invention ~.s directed to the above fuel. sell, wherein the carbon bladk is present from the ~s~xtalyst layer side of the g 11~ diffus~.on layer to an ~sppc~site side theweof A twelfth aspect of the present invent3.on ys d~.redtc~d to the above fuel cell, wherein era amount ~of the darbon black with whidh. the gas diffusiam~ layer is f~.llesd is ~. mvglcm~ to ~~ mg/cmz.
~~zEk' DE$~RIPTION t~F ~'HE' DRAWxI~CxS
FIG. 1 is a main sedtidn assembly view showing a constitution of at,fcmi dell adaarding to~ the present invention:
2o FIG. 2 is a s~shematic sectional viewr of the cell of FIG. ~.;
k~'rG. 3 as a partially e~cpande~d ~~eotional view of a g8s diffusion layer of an anode df F=(.F. 3.;
FIG. 4 is a v~.ew sht~wing a relata.on between a ZS current and ~a~. voltage in each of a c~el~. of are embodiment ar~cx a donventional cell; and.
FIG. 5 is a partially expanded sectional v3.sw of a gas diffusion layer of a Gonventioaal an<>de.
DE~.'AIhEI? DESGRIFTxt~'t~1 tiF 'sHE P'1~,EFERRED EMLiODIt~NT
Newt , a prefea~aced embodiment of vChe present invent~.an will be des~ori.t~ed in detail wiiCh ref~sz~ence to the accompany3.ng drawings . ,A fuel cell 1 of the embv~dament is a direst methanol types fuel cell (DMFC) which generates power by directly supplying a liquid organic fuel such as methanol or darnesi~hyl ether ( DMg ) from a fuel supgly source ( sot shown ) to am anode 2 . axxd oxygen ( o:Kidant g~.s ) Gdn'~3lned j.w air to a cathode 3. A constitr.~tion o~ the fuel sell 1' of the embod3.ment will be der~cribed by referring to FIG. 1. FIG, 1 ~.s a main s~sot~.on assembly view showing the eonstitutian of the fue:1 sell 1.
~.5 The fuel cell 1 aamprises a dell iCt in tahiah the anode (fuel. electrode) 2 and the oathode (air e~.eatrode).~
are arranged on both surfaces of an ~elecitro7.gte. membra.~ae~ 7, and a pair of separ,~tors 8, 9 equipped w:~th ribs to hold the oell therebetw~e~rn .
2U The s$psratc~rs 8. ~ are can~t~.tu~t~sd of conductive substrates prepared by eiabarately prose»sing carbon plates. 13,n anode channel (fuel pa$sage) 21 is constituted of a plur8~l~.ty of grt~o'tre~ in the sep.~ratwr 8 of the anode side . A aatlaad~a channel ( six paes~age ) ~.;~ is e3.m~.~.ariy 25 constituted of a piural~.ty of grooves in the separato~c ~ of the cathode side.
Gaskets 1~. 1~ axe disposed as se$ling materials -betwreen an outer peripheral part oaf the .electra7lyte membrane 7 and outer peripheral parts of th$ separators 8, 9, and then the cell ~.a is held between both, sides of the separators 8, 9 to constitute a cell un~.t 5. Further, a p~.urala.ty of such cell units 5 are stacked on coach other, and bot-h ends o~ the laminated cell unit 5 are he~.~d b~'~~esen end plates ( not shown ) tar oc~~atitute the: fuel. Gel.. Z _ Additionally, ,r~,t corners o~ the separators 8, ~,..
through-~ho~.esc 1 f . 3.7 , 18 , and ~. ~ era fox~ned . to const~Ltute manifolds ~or s~upplying/disoharging the liquid fuel or a.
reaction .gas . ~hc~ through-hales 17 , 19 ther$amoxxg are com~nun3.cated with the ~anvdea char~r~el ll..c~f tlae .s$paratrar 8, and the through-hole~~ 1~, 18 are communicated. with the:
cathode channel ~.2 of the separata.r Aaoording to the embor~3ment , fo=: e~am~le . 'the eleotaro~.yte malrtbraa~c~ ? ~.s cc~rrs~t3.tuted of a pea~f ~.uoro~sulfonia acid g~o3.ymesric film (. es . g . , NB:f ~.on 11.'7 ( produ~et name ) ) which is a ration eacchanger, and a thicskness of the e.l~ctrc~lyte membrane 'J i$ about , a . g . . 175 dun. Additionally. the electrolyte membrane ~ is forrn$d larger than the anode 2 and the cathode 3 by a~
predetermined sine, i.e., a syze which c:a,uses no lnconvex~.xe~nce in miniatura.zation of th~a cell 1 itself _ According to the embodiment, the: ele~stxo~.y'tes ~5 membrane 7 uses the Nafion (product seams,) as the nation c3xchangee.r _ zn addition to this , a fluaw3.xret-oot~ta-fining polymer ode' a hxdrocarbon polymer to which a su7lfon~.c acid -group, a hydx~raxyl groug or the tyke is added, a po~,ymer which cont~t,9.x'a.s a txa.s~ic functional group such as polybenzimida~Qie or the ll~ce, oae a complex thereof may too used.
on the .other hand, as shown 3n FIG. 2, the anode 2 has a laminated structure wf a gas diffus~.on layer 20 and a catalyst layer 2~.. iiere~.nafter, descriptxc~n gill be made of ( 1 ) a coristi'G~ut3.on of the gas dxff'4xs~.on layer .20. ( 2 ) a constitut~.rin c~f the catalyst layer 21, and ( ~ ) ~ a, metht~d for 1t~ preparing the anode 2.
(1) Gonst~.tut3on of the gas diffusion layer 20 The gas da.ff~x$ion layer 20 will be ~ d~ssscribed by referxing'to FIG. 3. FIG. 3 is a partially expanded view of a surface of a side vpprc~$ite the catalyst ~ layer 21 of .
the gas diffusion laye~x~ 2U pahich constitutes the anode 2.
~h~s gas diffusion layc~x 2O is aonstitute~d by coating carbon pap~ar as a conductive porous suggac~rt mx~d~s of carbon f~.bers 22 formed ~.nto woven cvr uawoven olc~th with prolyvinyl hlcohol (not shown) as a hydrophilic material., and f~.~.l~.ag an aperture 23 formed between tree carbon fibers 22 ~ntith carbon biac7c 2 4 as a conduat.ive povJder .
f7CTLE OF THE INVBNTTR~N
FUEL CELT.
BprCICC's1t01'J~?F~ OF THE TNV~:NTIt7N
The present invention acetates to a fuel cell which directly r$ae3.~r~ss a liquia9. fuel to generate poster.
The foal cell takes out chemical enea~gx which a fuel (hydrogen or the li3Ge) has directly as electric energy by electrode reactircen. and is a power gemeratioa system which has almost no adv~srse ir~fluence az:~ an envircrnrnent because a reaction product is only v~ater in principle.
CQnventiunally, a hydrogen-rich g~xs which is a reformation ~sf s source gas has been used as the fu~sl. In such a case.
~.5 heawever, a refaxmsr m~s~t be clisposecl in the pow$r generation system, c~ceating a $roblam of an enlarged device. 2'hus, 3n order to solve the prrrblem of ~~ievice enlargement , s. fuel cell Iaas be~e~n de~trelmpc~d which d~.rectly receives a liquid fuel to generates power .
In the conventional direst liquid fuel type fuel cell wh3.ch uses a liquid as the fuel, ~c~r examgle~. a call xs constituted by making ~, solid polyme~r~.c c~ta.c~n exchanger an electrolyte metnbxsne, and holding bot;km. s~~.c3.es of the elststxaly'G~a membrano between n anode rind a cathode . The anode has a lam~.nated structure of a gay; diffusion layer Constituted of woven car unwav~sn cloth nna~de of carbon fibers and, a platinum and ruthenium c~antaining ca,tal~st layer -d3.spased thereon. A liquid fuel such as methanol or dunethyl ether ( D) ~.s supplied to the axaade , while s.~.z~ s~s supplied as an oxidant to the cathode.
°~hus, electrochemical axidetion reaction of the liquid fuel c~ocurs in the cata~.yst 1ay$r of the anode to gen$rate ,a pratan ~ I~+ ) . The pratan movers through the . slecfirolyte rn$mbrane to reach the cathode. At th3.s ~t~.me, an electron ~.s taken out to $n externaX cirGUi'G to. be used as electric energy. Cn the other hand., in the cathode, the iQ proton moved through the eleetralyte memEbrane reacts w3.th oxygen in air to generate Water. Further. ~.n the anode:
carbora d~.oxide is r,~er~erated as a main pr~r~dumt . and discharged to the outside s~f the cell system.
Here, according tc~ the fuel ce~.l, 3.n ardar to ~srncsottsly supply the liquid fuel a.n the anode, a pox~r~u~s rnc~t~ar~.al of the gas diffusion layer sss . made of carbon paper treated;.by palyfluoroethylene ~~,bers to .improve wtttesr .
re~pe~.~.ency (see PCT National PubliG,~t~.on No. 11-51~D3~.~1~.
la:LG . 5 is an es~panded view of a carbon fiber on a ZO liquid fuel supply side of a gas diffusion l~.ayer. ~n the drawing, a reference numeral. 101 denotes a c~bon fiber of a porous material which aonstitutes the 13.c~u~.d fuel su~xply side, and a refez~ence numeral 102 denotes an aperture ~ormec~, bstweeri the caxban fibers 101. A. reference numeral 103 dez~vtes methanol which is the liquid. fuel. suQplied to the gas d,3.ffusiexa layer o~ an anode side .
However, in the aforementioned C~c~nventiona~. ~ue1 _.
cell , because of th~a water repell~ency o~i: the. porous material used far' the nod~, as shown in FYI. 5. it 3.s d~.~f~.~cu3.t for the methanol 103 which is the liquid fuel to persne~tte the carbon fiber ~.~7~. of the porr~t~s mat~rial.
Consequently', a r~duction occuxs ~,n permeab3.3.3.ty of the methanol inta the anodes. Therefore, suifia~.ent supplying of the methanol which is the ~.lf~Lll.d ~lyrB~_ to the cats,~.yst layer' of the anode is impossible, causing a problem of an increase in coz~.cerrtxation polarization of the methanol in ~ the anode.
' SUMMA3LtY Cl=' T~I~ TNVBHTION
' . Aa ab jest of the ~rresent iavent~.on is to provide a fuel sell capab7.e of imprav~.ng an output: . by reducing .
concentration polarisation of a li~u~.d ~'xel a.n an anode.
A ' fa.~cs~'C aspect of the present irrveation is .. . dir~ecte~d to a fuesl ce~.l which comp~Cise~s an ~ anode and a c$thode an both surfaces o~ an.ele~strolyte membrane, suppliers a liquid fuel to the anode, supplies au o~idaaxt g8i.5s to the cathode, to react tht~ ~ liquid fuel with the oxidant gas and to gr~nerate power, whare,in the x~rrade comprises a~. ga.s d3.f~u$ion Zayer constituted by fi.lllt~g a conductive porous ~auppor't 9ohich is coated w~.th a hydrophilic material w3.th a conductive powder, and a 2S catalyst layer.
A second a$pe~cst of the pr~saer~t ~.nvention 3,.s directed to the above ~txel ce~.~., wherein the porous support .. 4 -3s made of caxbon f3.bers .
A third aspect of the present in~,r~snt~.on is dixectad to the above ttxel ~$1,~., wherein, the gas diffusion layer Qontains 5 t~at% to 64 vvt% of th~x hydxt~~rhilic material with respect td a sum total of the conductive porous support arid th~a hydrophilic matexial.
A fnurth aspect of the present j.nverit~.on ~.s di.reoted.to the above fuel tsell, where~.n. the, gas diffuse~.on ~.ayer contains ~t~ ~vt% to 4Q wt% o~ the hyc9xophilic material Zo with resspeCt to a earn total. of the conductive pox~c~txs support a.nr~. the hydrophilic material.
A fifth aspect of the present irment~.on; is directed to the above fuel cell, wherein tlxe .Conductive powder is . carbon b.~.aCk.
1~ . A s3~.xth aspect of the p5ce~seat invention is directed to the above fuel ce7.l, wherein a water-repellent tnxtter~.al. is added to the carbon blank.
A seventh aspect ref the present invent5.on is dires3ted to the above fuel cell, wherein. S ~rt% to 80 wt% of 20 the wat~xr-repellent material with respect to the sum ~COtal of the conductive porous support axxd they grater-repellent mtaterisl is added tc~ the caxbon blscsk.
An eighth aspect o~ thp pr~s~teat invention is directed to the t~bove fuel ae~,~., wherein 20 wt% to 4~1 wt%
a5 of the vrate~r-repel~.ent ms,terial with respect tc~ the suns tt5t~ea. of the oonductivr~s poxous stapport acrd tY~e v~atesr_ repellent matex~.a~, is added to the carbon blacx.
_ r,~ _ A niz~th aspect of the present inventa.on ass directed to the abovr~ fuel cell, wherein a, dibutylphthalate absorption of the carbon blaol~c is 160 ml./~,Ot~ g or more.
A tenth aspect o~ the pre~g$nt in trention is d~.xected tc~ the above fuel dell, wherein a. dibutylphthalate absorption of the dar'boa black is 36e m~./ ~.01~ g wr more .
An eleventh aspect of the pr~sser~t invention ~.s directed to the above fuel. sell, wherein the carbon bladk is present from the ~s~xtalyst layer side of the g 11~ diffus~.on layer to an ~sppc~site side theweof A twelfth aspect of the present invent3.on ys d~.redtc~d to the above fuel cell, wherein era amount ~of the darbon black with whidh. the gas diffusiam~ layer is f~.llesd is ~. mvglcm~ to ~~ mg/cmz.
~~zEk' DE$~RIPTION t~F ~'HE' DRAWxI~CxS
FIG. 1 is a main sedtidn assembly view showing a constitution of at,fcmi dell adaarding to~ the present invention:
2o FIG. 2 is a s~shematic sectional viewr of the cell of FIG. ~.;
k~'rG. 3 as a partially e~cpande~d ~~eotional view of a g8s diffusion layer of an anode df F=(.F. 3.;
FIG. 4 is a v~.ew sht~wing a relata.on between a ZS current and ~a~. voltage in each of a c~el~. of are embodiment ar~cx a donventional cell; and.
FIG. 5 is a partially expanded sectional v3.sw of a gas diffusion layer of a Gonventioaal an<>de.
DE~.'AIhEI? DESGRIFTxt~'t~1 tiF 'sHE P'1~,EFERRED EMLiODIt~NT
Newt , a prefea~aced embodiment of vChe present invent~.an will be des~ori.t~ed in detail wiiCh ref~sz~ence to the accompany3.ng drawings . ,A fuel cell 1 of the embv~dament is a direst methanol types fuel cell (DMFC) which generates power by directly supplying a liquid organic fuel such as methanol or darnesi~hyl ether ( DMg ) from a fuel supgly source ( sot shown ) to am anode 2 . axxd oxygen ( o:Kidant g~.s ) Gdn'~3lned j.w air to a cathode 3. A constitr.~tion o~ the fuel sell 1' of the embod3.ment will be der~cribed by referring to FIG. 1. FIG, 1 ~.s a main s~sot~.on assembly view showing the eonstitutian of the fue:1 sell 1.
~.5 The fuel cell 1 aamprises a dell iCt in tahiah the anode (fuel. electrode) 2 and the oathode (air e~.eatrode).~
are arranged on both surfaces of an ~elecitro7.gte. membra.~ae~ 7, and a pair of separ,~tors 8, 9 equipped w:~th ribs to hold the oell therebetw~e~rn .
2U The s$psratc~rs 8. ~ are can~t~.tu~t~sd of conductive substrates prepared by eiabarately prose»sing carbon plates. 13,n anode channel (fuel pa$sage) 21 is constituted of a plur8~l~.ty of grt~o'tre~ in the sep.~ratwr 8 of the anode side . A aatlaad~a channel ( six paes~age ) ~.;~ is e3.m~.~.ariy 25 constituted of a piural~.ty of grooves in the separato~c ~ of the cathode side.
Gaskets 1~. 1~ axe disposed as se$ling materials -betwreen an outer peripheral part oaf the .electra7lyte membrane 7 and outer peripheral parts of th$ separators 8, 9, and then the cell ~.a is held between both, sides of the separators 8, 9 to constitute a cell un~.t 5. Further, a p~.urala.ty of such cell units 5 are stacked on coach other, and bot-h ends o~ the laminated cell unit 5 are he~.~d b~'~~esen end plates ( not shown ) tar oc~~atitute the: fuel. Gel.. Z _ Additionally, ,r~,t corners o~ the separators 8, ~,..
through-~ho~.esc 1 f . 3.7 , 18 , and ~. ~ era fox~ned . to const~Ltute manifolds ~or s~upplying/disoharging the liquid fuel or a.
reaction .gas . ~hc~ through-hales 17 , 19 ther$amoxxg are com~nun3.cated with the ~anvdea char~r~el ll..c~f tlae .s$paratrar 8, and the through-hole~~ 1~, 18 are communicated. with the:
cathode channel ~.2 of the separata.r Aaoording to the embor~3ment , fo=: e~am~le . 'the eleotaro~.yte malrtbraa~c~ ? ~.s cc~rrs~t3.tuted of a pea~f ~.uoro~sulfonia acid g~o3.ymesric film (. es . g . , NB:f ~.on 11.'7 ( produ~et name ) ) which is a ration eacchanger, and a thicskness of the e.l~ctrc~lyte membrane 'J i$ about , a . g . . 175 dun. Additionally. the electrolyte membrane ~ is forrn$d larger than the anode 2 and the cathode 3 by a~
predetermined sine, i.e., a syze which c:a,uses no lnconvex~.xe~nce in miniatura.zation of th~a cell 1 itself _ According to the embodiment, the: ele~stxo~.y'tes ~5 membrane 7 uses the Nafion (product seams,) as the nation c3xchangee.r _ zn addition to this , a fluaw3.xret-oot~ta-fining polymer ode' a hxdrocarbon polymer to which a su7lfon~.c acid -group, a hydx~raxyl groug or the tyke is added, a po~,ymer which cont~t,9.x'a.s a txa.s~ic functional group such as polybenzimida~Qie or the ll~ce, oae a complex thereof may too used.
on the .other hand, as shown 3n FIG. 2, the anode 2 has a laminated structure wf a gas diffus~.on layer 20 and a catalyst layer 2~.. iiere~.nafter, descriptxc~n gill be made of ( 1 ) a coristi'G~ut3.on of the gas dxff'4xs~.on layer .20. ( 2 ) a constitut~.rin c~f the catalyst layer 21, and ( ~ ) ~ a, metht~d for 1t~ preparing the anode 2.
(1) Gonst~.tut3on of the gas diffusion layer 20 The gas da.ff~x$ion layer 20 will be ~ d~ssscribed by referxing'to FIG. 3. FIG. 3 is a partially expanded view of a surface of a side vpprc~$ite the catalyst ~ layer 21 of .
the gas diffusion laye~x~ 2U pahich constitutes the anode 2.
~h~s gas diffusion layc~x 2O is aonstitute~d by coating carbon pap~ar as a conductive porous suggac~rt mx~d~s of carbon f~.bers 22 formed ~.nto woven cvr uawoven olc~th with prolyvinyl hlcohol (not shown) as a hydrophilic material., and f~.~.l~.ag an aperture 23 formed between tree carbon fibers 22 ~ntith carbon biac7c 2 4 as a conduat.ive povJder .
(2) Constitution of the catazyst layer 2~, Further, the cata3.yst layer 21 ~.s ste.cked on a surfatse opposite $ lic;uid fuel. supply $s~de rxf the gas diffus.~.on 1$yar 20 constituted 3.n the s,f~orementior~ed manner, The catalyst 7.syer 21 is formed by mixing plat~.num-ruthenium bleak w~.th .~: cati.on e~tchanc~er such as _ L3 ..
Nation (product named arnd, e.~., a screen pr3riting method.
Nation (product named arnd, e.~., a screen pr3riting method.
(3) Method for pr~p~r~g the anode 2 of the embodiment Regarding the a~xode 2 ~f the embodiment, to begin ov~.th, pos~dered polyvinyl aicoheyl as a hydrophilic material is d3.s~per~sed in an ethanol a.c~ue~c~us sdlut~.orr, grad csarborx paper as a ~spntluctives porous support is dipped in the solution. Here, for e~cample. ~sa~rbon black of QUO ~m xn thickness i: used, and ~uffir~iently dipped ~.n the ~olv~tlon.
Acaordixag to the embadimant , by us~.r~g G~urbt~n pap~r made of 1t1 carbon f~.bers as a conduct3.ve porous support, the po~eous support hav3.ng an apertures ~3 can be easily prepared, whereby _prradtxGtivity cant be imp~'ov~sc9,.
Subsequently, the carbon paper dipped ~.n the.
solution is heated .to about ~r~0°C, Fund tha ethanol ac,~ueous.
15 solution ae a solvent is xemoved- Further, the ca~rbo~x .
pspex i.s tieStead to about t~.50°C tc5 bs burred. RCCOx'd~.ngly, .
a conductive porous, support coated with the hydrophilic material is prepared. Incidentally" in this case, the hydrophilic material. is added so that 3.ts weight ratio can Zt? be 5 wt% to 6t1 wt%. pr$ferably ~0 v~tt% to~ 4Q ro~rt%, vrith respect to the adnduetive porous suppox't coated therewith.
tan the other hand. a po3.ytetraf~.uoroethylene dispers~.on liquid as a wa.tex~-xe~pelZent material is mixed w~.th carbon black 24 as a. aonduat~.ve ponder to prepare 25 slurry. Aac~ord3.ng to the embodiment. as the carbon black 24, especially lceok~en blet~sh SC (product name) whoS~e d~.butyZphth~rlate absox~pt3.on is 160 ml/lO~g or more, prefbrab~.y 36A ml/100 ~ or more, S.s usec~l. Addit~.anally, the embodiment ~.tse~s the carbon black to which polgtetrafluorot~th3r:Lene as a water-repal.lent mater3:a~, is added by 5 wt% to 8f3 wt~, preferably 24 v~t~ to 40 wt~, with xesp~ct to a soma fatal of thg condu~stiww porous supgort and the water-repellent ms.texial.
Then; tl~e ~shxrry is coated in trte conductive gorous~supgbxt coated with the hydrophi~,ic material, i.a., the.carbbn paper formed in the aforementioned snann$r, by a ~.0 blade knife or the lilts to ~il.l the same. At this time, a fia,.ling amr~unt of the s7..urry in the Carbon pap~sr ~.s set so that a filling dens9.ty thereof can be aba~ut 5 mg/cms.
Accordinr~ly, the carbon black ~4 tc~ which the water-..
repellent material kras been added c~dn~ta.n;u.aus~.y ~313.s th~x aarban paper as the pora~s sugport fz~om its liquid fuel supply side to the catalyst laxer 2~. side. ~ubsequent~ly.
the c~txbon paper is heated, to at~out +x.50°C to be burn$d:
Thus, the ga.s diffusion lstye~c 20~ of the anode 2 is frirrn~sd.
Then, platiwuci-ruthenium black ass a ~at~a~.yrt parti~la is mixed with 5 wt$ Nafion (product nam$) as a catian exchanger to pz~epare a catalyst la~Yar inl~. The ~ataly~t layer ink is aerated on the gas ~i~.ff~zsion layer 2f~
by a screen printing method to cQmp~.,et~s the anode 2. rn this aa.se, the agtalyst layer inlc 3.s prepared so that a we~3.ght rati.cy between ache vatalyst particxe r~.nd the Nafion (product name) a.s the ration exchang~sr can be catalyst:
Naf ibn ( product ty ame } m 9 : 1.
~n the other hand, as shown ~.n F~G~ 2, the cathode 3 is structured by sequent~.aa.ly stackir~~ a gas diffusioxx layer 26 ancT a ct~talyst layer 29 from the outside to the e7.ectrolyte membrs.ne 'T side. The gas di-.~fusian i~tyer ~~r is foamed by mi~cii'rc~ a polytstrafluoxoe~trryl$ne dispers~.an l~.qua.d as a water.~a~epellent matex°ia1 and carbon bleak 24 (xe~ahen black EC (product name) 3.s used an the embodiment) ' as a~conduati.ve pcwdsr in carbon paper a~~s a conductive porous ~~xpport dipQed ~.n pc~lytetrailuoro~e~thylene as ~
water-repellent material to fill the sam~a as 3.n the ease of ' the anode 2.
w The eata~.yst layer ~T :Ls Formed by m~5.ng platinum black a.s .~ catalyst ps.rtiole with ~ wt% iNa~~.on (product aamr~) as a ration exchanger tc~ g~repare 'a cataly$t lager ink, r.~nd coating the catalyst l~eyesr inx on the gays diffusion layer ~6 by a screen pr~.ntinc~ nnethr~d..
=ncsideataily, ~t~ in the grewious cs,se~. t.'he catalyst lay$r ink is pz~ep8~re~d ss~ that a ~rrt~ight ratio b~atween the cas,ta,a,yst particle and the NafioxE. ( product n~un~s ) as the ration ao exck~anger can be catalyst : Nafion ( product name ) ~9 :1. .
Th$ cell. 10 a.s con~ttituted by holslin~ the electrolyte membrane 'T between the electrodes 2,~, arxd executing adhesa..vmnolding by hot pressing at abou'~ +150°C
while the electrc~c'i,as ~, ~ are held between the separatoxs 2S 8, 9.
Next, description will be made o~ a difference its, output between the cell 1i7 r~~ the embodiment and the -~sonventional call in which the mater-repellent material ~.s added to the gas diffusion layer o~ the ~~nt~de by referring t0 FIG. 4. F=t3. 4 is ti view sh.t~w3.ng a relat5.on 'between a curresnt ~.ne~ a voltage in each of the oall 10 of the e~eebod3.mer~t and the convex~,tiorsa~.~. cell. Fear the sell 1~D o~
the embO~diment, the call prepared in th~x aforementioned manner 3s us~d. For the convem.ty~nal .cell, . a. cr~l1 in wh~.csh an anode is constituted eimilar~.y to the cathode 3 of the c~mbodimen~t is need . That . zs~ , the conventional ce~.~, u$es the anC~da and the cathode in both Of which roister-rep~alleitt materials axe added t0 gas diffusion layers.
Inc3.dentally, . FIG. 4 shows measurement of pd~arer gen~sration charatsteristics at +6o°C by using a -meth~ol aqueous sohxt~.oa of a. ooncer~tration ~, mol/L as a ~.iquid final for $ach cell, ~tnd. supplying sti~c as an oxidant gas.
black Square indicates a measux~tng result of the sell 10 of the ~ embodiment , and s white sc~uarE~ indicates a. measuring remxlt of the conventional c~u~.~..
From the drawW rrg, it aan bs und~:rstood that poorer generation oharacterist~.cs ors high~a~ in .the cell. ~.U of the embodiment than that ixx the aonvent~.ona1 cell at a high current density. ~hi$ rnay be attributed. to improve~m~snts of supply eafficie~ncy of the liguid fuel in the anode 2 and disahaxge e~ff3oie5ncy of carbon da.oxide ges,erated ~.n the or9.talyst layer 21 over those Of' th$ convent~.on~al call.
Thus , iii the fbe3. call 1. the liq~y.ici fuel is supplirtsd to tk~e l~.quid fuel st~p~rly manifold. ~cef the cell l~ -unit 5, and ai.r is supplied to the oxidant gas supply manifold. Then, the liquid fuel sugpiiec~ to the liquid fuel. supply manifold is d~.~ltribute~i thr~augh eauka anode channel 11 to he supplied to the anode :~. Oa the other hand, the a1r supplied to the oxidant gas supply man~.fc~ld i$ supplied through each cathode channel 12 to the oa.~thOde 3. A superfluous gas is discharged from: the v~ci.dant .gas discharge man~.fp~d.~
i3er~ , for tine liqu~.dl fuel srup~al:yed to the anode 2 , ~.O ~~.nce - the carbon fibers 22 8f the gasp d:Lffus3.o~n i~.yer 20 axe coated with the hydxoghi~.~.c materials as described abtrv~s , a hollornt p,'xx't hs~v3.ng hydrophiliaity can be f orcned in the oarbox~ ~ f~.bax 22 near the surface of. the ;porous .suppoxt.
and a l~.qix~.d fuel passage C~a.xl be formed to supply the li.quira fuBl to the catalyst layer. 12 formed on the electrs~lyt~ membrane '~ side of the anode ~ 2 . ..~speci~tlly. by ~contaiaing 5 ~vt% to stt wt%, preferably e':W-~vt% ts~. 4Q arty, of the hydrophili~s material in the coaduotive porau~ Support c~oate~d, therewith as described above, it is possible to more 2o improve d~.ffu~ibility of the liquj.d fuel.
Aor.~~Gx'd3.ngiy, as irsdicate~d by a solid-line ai'~roar C~f FxG. ~, the liquid fuel permegte~s the porous support thz~r~txgh the liquid final passage. Then, aftex the Z3qu3d fuel is roughly un~.foxmly 8lffused through the ga$
diffusion layer 20, it permeates the cataly$t lrayer 2~, arsd srrode reaatioia ~.~ caused 'by a catalyst c~f the aata.lyst layer 21 to oxidise t.he~ l~.quid fuel ( ohenni~aaJl formula ( ~. ) ~ s CH30H-~HaU--YCtJZ+fiEI'"+6e- . . . ( 1 As indicated, b~,s a dotted-line arrow of FzG. 3, carbon dxaxide generated by the anode reaction in the catalyst layer 21 is di~charge~d tts the csutside through stn aperture ( smell ho1$ ~ in the structure df the carbon biacsk 24 as a conductive poarder fully s~uppl~.ed t~et~esrn the carbon fibers v2 of the gas c~i~~usir~n .layer 20. The apertuxe fozmad ire the carbaxx b~.aals 24 is not closed °by the permeation of th,e l3.quid fuel becsause ~.1: is small. A gas such as carbon d3.oxide gen~arate~d in the catalyst lever 21 cyan be easily d~.sch$rged tharethxaugh tt~ the outside .
Espea3.ally, accoacd~.ng tv the embsadimexxt. $ync$ the carbon blacx ~.2~i r~onta.n~xousyy fills the caxbon paper as the porous support frown its liquid fuel ~3upply side to the catalyst layex 21 side, a liquid film of the lic,~u.id fuel formed on the ~ liquid i~uel supply sides of the gas d~.ffusion layer 20 becson~s discn:r.txnuou~s. and a discharge passage of the aerbon dioxic~ generated in the catatys~t layer 21 can be sv~xwly obtainesd. Thus , ixtconven~.ence~ c~f staying of the 2o caxban dioxide generated in the gas di~~u$ion layer ~(~ wan be prevented. diff~ut~ribi~.ity of the l~.c~uid i'u~al in the anode 2 can be 3 mprvved, ~xono$ntratiQn p~rlarization of the liquid fuel in power generation canx be reduced, and perfQx-cnan~ce of the fu~sl ce3.1 1 scan therefore De improved. ~nc~.dent8~~.ly, the performance imprQVeament df thaw fuel cell 1 0~ the inveiat,~.on 3.$ also apparent Exam ~eua experiment x~sua.t ttf FIG. 4.
~laac~rd~.ng to the embod~.ment , far the carbon b~.ack Z4, by using r~x~rbon bleak whQ~3e ~iibnstylphthalate absorption is z60 ml/10~ g ax more, or 360 ml/~.d0 g ax nmrre, it is possible to secure s large aperture valurne i.n the structure c~f the aarban black. and to imprava dischas~ge efficiency of th~ carbon dioxide.ms~re.
Further:. acac~~rding to the embod3.ment, s.3.nae the o~atex-repellent material i.s added to this carbon black 24 as' desaribod - abo~re , it is poss3.ble to prevent iaaanvenienae of its closing of the 8yr~srture in the struc~tu5~e . the~rr~of by the liquid foal, and to smooth~.y discharge the carbon dioxide .
g~xrrerated .~.n the vataly~st layer ~~L through the apertures ~.n the struaturw of the carbon bleak 24 to the ou.ts~.de~.~ . . .
Maxecwe~r, it is possible to suppress a. ~:educt~.on in an .
x5 output of the fuel cell itself taaused by, c~onduGt~.vity di~r3.sion~. . .
Sspec~.ally, regarding the amc~uni, of the arater-repellent mat~rial added, to the Caz~ban black ~4, S v~t% to 8t1 a~tt%, pr~3ferably 2Ct wt% ts~ 40 wt%, of the water-repellent 20 material is added with x~aspeGt to the sum total of the ao~tduGtive porous support and the water-repellent material.
~rocordingly, it is pc~ssib~.e to 3:mprove discharge effic3~ex~cy trf the aarboa dioxide generated ire. the cata3.yst layer 21.
A ,proton generated by the a..forc~mentioned anode 2S rear~tion causes o~cidation reduction reaction with oxygen ( oxidant gas ) conta3.n~sd a.n the air supplied to fihe c~dthode in the elevtrolyts me~ebr~,xse 7 to generates gowex ( chemical - Z~ -formula: (2)). =nci8entally, this power generated here is contrt~llad b~,r a control device (not shoe) as contxol means for poorer generation .
3/20Z.rtSFi~+6e--~~I~a~ . . . ( 2 Hy flee . aforementioned constitut~.on, acc~c~rding to the embodiment. the liquid fuel supplied to the anodd 2 can bs uniformly d;3.f~ussd in the gas diffu~~.c~n layer 2(? through the hyc'ixoQhilio liquid fuel pa$sage~ nee=: the surface of the porou$ support which constitutes the gays diffus~.ra~n layer 20 1o to permeate the catalyst layer 21. Thug, concentration po~.~isat3.on of the ~ liquid f~ac~i is reduced to enahle improvement of the performance of tk~.e f~;~el csl~.. ' . ..
Additionally, since the apartura~ formed xn the poro~.as~ support is fx~-~-ed w5.th th~ conductive poa~t~,er to which the water-'reQellent material is added, it is possible to discharge the oeu~bon dioxide generate6 in the Catalyst layer 21 to ~ the outside through the s~mal.l ~ hole :formesd xn .
the coaduotive po~rder. .~cco~cdingl3r, it is goss3,ble to reduo~e the concentration ~olar3.xation of the liqu3.d fuel in 'the anode 2.
Acaarding to the embodiment. slues they carbon black 24 to which then water-repel~.e~nt material is added fillss the' conducta.~re~ porous support by 5 mg/cmx, the eonduat3.ve powder can be present Exam the catalyst layex 21 .25 side o~ the gas dif~usi.on lager 20 to the opposite side.
fih$ liquid film of the liquid fuel formed nn the liquid fuel supply s3.de of the gas di.ffu~ion a~.'yar 2p t~ecomes disaontinuoos . Thus . ~.t is possible to ob!tx~~.ri. th$
discharge passage of the Garbtsn dioxide generated in the oatalyst layer ~~. more surely.
Incidentally, according to t~xe ~~c~tbodiment , the carbon blaoJc 24 to whioh the waterre~pe~7llent material is W added fills the couduot~.ve porous suppt~~.~~t by about 5 rng/cm2. w However, by setting the ams~unt. eaf cs,rbon black 24 to x mg/om2 tc~ 20 m~.~''~can2, the Carbon bZs.~c7e ~4 os.n beg gropexly present in the gas d~.ffusiow layex 20 from the ~ oatalyst layer 21 s3.de thereof to~the opposite side.
Additsonally, it is possi'61e to prevent closing elf the .
aperture of the porous support caused by filling with .
excessive carbon black 24. lens a r$s~tlt, it ~~.$ possible to prevent 3.nterference ar~.th diffusion of tk~e liquid fuel.
. ~. According ao the em'bod,iment . the carbon paper is use~d.~s the conductive porous support. =n addition to this. a carbon f~.ber of unwoven cloth, aroven carbon cloth, or a metal mesh such as a platirwun mesh or a gold-coated coppex mesh map be used.
AGCOrding to tl~e embodiment , they polyv3.ny1 alcohol.
is used as the hydrophil~.c material coated an the carbon paper. =n addition tee this, palyv~.ny1 pyr~ra~.idone.
pa~.ybE~naimidazole, colloidal ~oili~aa, tit~an3,unn oxide or ~eosite may be used.
2s =n t~rder to prr~v~.de~ more urr~.fc~rrtt hydrophiliaaty 'to the, conductit~e porous supgort , a ~aalymer~isa mater3.sv1 .among hydrophilic mater3.e~.1$ is preferably used,. Further.
regarding the a$dit~.on amount of the hydroph.il3.c~ material.
by setting a weight ratio to ~ wt% to 61~ wt%. preferably 20 wt% to 40 wt%, with respect to they aonc3uative porous support coated vo~ith the hydro$hil~.G material as described above, it is pcr~ss3ble t4 improve d~.ffu~s,3b~.13,ty at the liguid fuel mofie .
Wurther, according to the bmbodime~nt, the 7~eohen bXaols EG ( product name j .is used as the rsonduvtive paroo~der.
Xn addition to this, other carbon blaclG such as harness 1~D black ore acetylene black may be used- :tn such a case; in order to improve dischar$e efficiency of the aarban dioxide generated 3.n the c~atal~rst layer ~~, s3.mi:L~arly~ to the . embo~d~.ment, s, larger aperture volume is prefearabz~a in a struCture~ of the conduCStive carba~n bla~.~
~'urtlaex~re , aacarding ~O they embodiment , the . .
polytetrafluoroethylene is used as th$ w~rater-repell$nt ~nateria~. added to the carbon b~.ack 24. Tn ae~ditian tc~
this. a fiuororssin such as a tetrc~fluox:aethylen~r-perf3.u~rroallcylvinyl ether aeapolymer, a 20 tetrafluoroethyyler~e-b.~dx.~fluoropropylenes ot~polymer, a polyvinylidene flucxride, polyfluorc~v3.nyl, p~e~fluoroalkoxy, tetrafluraethylene-ethylene copolymer.
polychlorotrifluoroethylene, or poye~htersulfrrne may b$
urea.
25 AGCOrding to the embt~c~.iment, they two~eloment a3.loy ~of the p~.atin~.un-swtheni~sm blacslC is ~.ase~el as the Catalyst particle ref the os7~talyst layer ~7. of the anode 2 , Tn -addition to thi$, a twro-element alloy ojE platimua~-molybdenun~. g~.at~-nr~m-iridium, platinum.-tin, platipum-tungsten, glatinuu~-'~it,an~.tvm~ or glatiriura-xhodium, or a multielsment alloy of three elements or more wh~.ah oambine such elements may be used. Additionally, a ~satalyst metal which caxri~es carbon bleak may be used.
Furtheza~nore, ~ a.oooxding to the ernbod~ant , the platir~um black 3s used as the cata~.,yst psrtial~ of the catalxst l~xy~sr 27 of the cathode 3. In addition to this, a 1t1 oannb3.natior~ of alloys which constitute the catalyst .. $,~iclt~a e3~ the catalyst layem 21 of the ,anode 2, or a catalyst metal which aaxriss caxbcn b~.ac:lc m$y be us~ad.
Iat~~.denta3.ly, according to they tumbodiment , the methana~. and the DMB are cx.ted ~s the liguid fuel.
~iawewex, similar effects oan be , axhibitt~d evc~ri by other ~.iqu~.d fuel such as pxopar~oi, butanal. trimethvxymethane, , .
e~thylene~ glycol, dr ad. f~rrmic acid. lsrCCOrding to the e~nnbodicnent , the s:3.r is cited as the oxidant gas . I3owever.
similar effects oars be exh~,.bited. by oxygen, a. hydrogen 2o peroxide solution or the l~.lce , discussed above irr detail, acaord~..ng to the present in~rention, the furt~s cell comp~cises the anode and -the cathode on both suxfaaes of the electrolyte membrane, supglies the lisZu~.cY. fo.e1 to the made. wu.pp3.i~~ss the oxidant gas to the cathod~ , atxd reacts thEe i~.c~ui~d fuel nrith the oxidant gas to s,~enesrate power . The anode oo~pris~s tht~ r~a,s diffusion layer coristitutod by filling the conductive porous support ~rh~.ch is coated with they hydrophilic material with the conductive powder, and -Che aata~.xst lager. Thus. the hydrophil3.c hollow part is formed near the surface of they porous sup~rcrrt of the gs.s diffusion layer, and the liquid fu~sl ~rassage can be formed to supply the l~.~uic~ fuel to the cat~xlyst 7.aye~r formed as the electrolyte mem'~srane sides of the anode .
The,ape~rture formed in the porous sugport is fihe~d w3.th the t~onduative gawdar. ln. thxs Casks, however, 3.d the smalx ho~.e is for~necl in the conductive powder. Thus, szno~ the small holm ~is not closed by, 1~'.he liquid fuel, a gas such as carbon dioxide generated in the catalyst layer 'aan be disch8~xged to the outside.
Therefore, concentration polarisation of the I5 l3.qu3d fuel in the anode ~.s reduCeB to enable .output .
improvement of the fuel ce~.l. .
Mere . the ptrxatts suppt~rt is made of carbon f ibexs .
Thus, they $orou~a support haviac~ an apar~:u~ee can be easily ooris~t~.tuted to improve productivitg.
fit! Add~.tiaaally, the gas d3ffvxs~.an Layer c3ontains 5 wt~ to 6o vot% of the hpdroph~.l~.o material with resgeat to the sum total of the ~:onduot~.v$ porous supgort and th~a hydrophilic material. ~cooxdingZy, diffusibility of the liqui.$ fu~ai oaa b$ improved more. Further, the gas diffu$ion 3.ayBr cbz~tains ZO wt% to ~O wt% of the hydrophilic material with resgoct to the sum total. of the aonduct~.ve porQUS ~sugpart and the hydrophilic material.
Accordingly, the tiif~u9sb3.13.'ty of the liquid ~uel Can be itnpraved mush mare .
In the foresgQing , the tsonduative powder is the carbon black. Thin, discharge efficiency ~o~ the carbon dioxide generated 3.n the catalyst layer can be improved.
Bspecia.l.ly, by wsiri~g they carbon blac% whose dibutylphthalate absorption is 7.60 mll100 g or more, or 360 mlJl~DO g or more,, a large aperture volmme can be seaurad is the . struatu~e of the ca:c'bcan ~ria~slc. Thus, it is ~ possible to 14 improve the discharge eatficiency o~ the aarboa dioxide mox~ . , . .
In each of .the aforemax~t3.orred ixaventio~as , the water-rege~.3ent material is added to the carbon biac7s.
Ac~aoardingly, it . is pass~.bie to pr$ven~t :~ria~rlavenisnoe Of Z5 a~.osir~g of the ape~acture i.n the strucstur~s of the carbon bl.acsiE Gausee~ by the i.iquid fuel. x'hus, it is posss~.b~,e ~C~a smra~othly discharge the carbon dic~xi.de generated in th~a...
aata.lyst layer to the outside through the aperture in the structure of trie carbon bxaCl~.
24 especially, 5 wt% to 80 wt% of i~h~r water-repellent materis.7. is add~ad to the Carbon black r~rith respwct to the sum total of the canduative porous support and the water-repeller~t material.. Further. ZO avt% to 40 wt% of tJla.~e crater-repellent material is adc'L~sd to the carbon black with 25 respect tQ the snm total of the Goriduative porous support oat! the wste~r-~repe~.leri.t mater3,al . ~.'hus , ~.'~ ~.s possiblev tcs ~.cnprove the dis~aharge efficiency of the carbon d~oxida -generated in the G~.talyst laxer.
Hy adding the water-repel7~ar~t ~riaa,terial to the carbon. black as descr~.bed above, it ~.s possible to supp~eess a reducstion in as out~sut oaf the fuel cell . itself' caused by conduativa.ty division.
Fuxther, the carbr~n black is present from the catalyst ~.a~rer side of the gas diffusion ~.ayer . to the oggo$ite side. Accordingly, the liqu3.d film of the 13.q~s~.d fu$3, formed on the ~l~.quid fuel ssupply s~.de of the gas 1o diffus~.on layer becoms~s dis~aontinuous, and it is possible to surely o'bt~ain the discharge pasrsage of . the t~arbQn 'dioxide generated in the aataiyst layer. w ~h~refare. it i:~ passibl~: to suppress ..
.in~onvenieace of alosiag of the os.rboa dioxide generated in 25 trie catalysst layer ix~ the anode, to impxove diffusibility of the liqix~.d fuel in the anode . aad to redua~e .
concer~tz~atiQr~ polariaatxc~n of the liquid. fuel in power generation, thereby i:mpro~r~.ng the pe~efo=:manc~a of the fuel coli.
2D Furthermore, aCCOrding to the isventian, 3.n th$
foregoing, by setting the amount of cs.rbon black f~.~.ling the gas d~iffusxc~n laye~c to Z mg,lema to 20 mg/csna, the carbon bleak ~san ba properly present in the gas diffusion lager from the catalyst layer' side there~rf tt~ the opposite 25 side . Additiona,Xiy, ~.t is possibhs to prevent closing c~f the aperttxxw ref the pc~roo.s scupport caas~ed by fi~.~.~.ng with ~xC~assive cnrtloxi black. As a result; it ~,s po$sible to Q~~vesnt interfersr~~e wii~h d3.~~usia~a of the lic~id fuel.
Acaordixag to the embadimant , by us~.r~g G~urbt~n pap~r made of 1t1 carbon f~.bers as a conduct3.ve porous support, the po~eous support hav3.ng an apertures ~3 can be easily prepared, whereby _prradtxGtivity cant be imp~'ov~sc9,.
Subsequently, the carbon paper dipped ~.n the.
solution is heated .to about ~r~0°C, Fund tha ethanol ac,~ueous.
15 solution ae a solvent is xemoved- Further, the ca~rbo~x .
pspex i.s tieStead to about t~.50°C tc5 bs burred. RCCOx'd~.ngly, .
a conductive porous, support coated with the hydrophilic material is prepared. Incidentally" in this case, the hydrophilic material. is added so that 3.ts weight ratio can Zt? be 5 wt% to 6t1 wt%. pr$ferably ~0 v~tt% to~ 4Q ro~rt%, vrith respect to the adnduetive porous suppox't coated therewith.
tan the other hand. a po3.ytetraf~.uoroethylene dispers~.on liquid as a wa.tex~-xe~pelZent material is mixed w~.th carbon black 24 as a. aonduat~.ve ponder to prepare 25 slurry. Aac~ord3.ng to the embodiment. as the carbon black 24, especially lceok~en blet~sh SC (product name) whoS~e d~.butyZphth~rlate absox~pt3.on is 160 ml/lO~g or more, prefbrab~.y 36A ml/100 ~ or more, S.s usec~l. Addit~.anally, the embodiment ~.tse~s the carbon black to which polgtetrafluorot~th3r:Lene as a water-repal.lent mater3:a~, is added by 5 wt% to 8f3 wt~, preferably 24 v~t~ to 40 wt~, with xesp~ct to a soma fatal of thg condu~stiww porous supgort and the water-repellent ms.texial.
Then; tl~e ~shxrry is coated in trte conductive gorous~supgbxt coated with the hydrophi~,ic material, i.a., the.carbbn paper formed in the aforementioned snann$r, by a ~.0 blade knife or the lilts to ~il.l the same. At this time, a fia,.ling amr~unt of the s7..urry in the Carbon pap~sr ~.s set so that a filling dens9.ty thereof can be aba~ut 5 mg/cms.
Accordinr~ly, the carbon black ~4 tc~ which the water-..
repellent material kras been added c~dn~ta.n;u.aus~.y ~313.s th~x aarban paper as the pora~s sugport fz~om its liquid fuel supply side to the catalyst laxer 2~. side. ~ubsequent~ly.
the c~txbon paper is heated, to at~out +x.50°C to be burn$d:
Thus, the ga.s diffusion lstye~c 20~ of the anode 2 is frirrn~sd.
Then, platiwuci-ruthenium black ass a ~at~a~.yrt parti~la is mixed with 5 wt$ Nafion (product nam$) as a catian exchanger to pz~epare a catalyst la~Yar inl~. The ~ataly~t layer ink is aerated on the gas ~i~.ff~zsion layer 2f~
by a screen printing method to cQmp~.,et~s the anode 2. rn this aa.se, the agtalyst layer inlc 3.s prepared so that a we~3.ght rati.cy between ache vatalyst particxe r~.nd the Nafion (product name) a.s the ration exchang~sr can be catalyst:
Naf ibn ( product ty ame } m 9 : 1.
~n the other hand, as shown ~.n F~G~ 2, the cathode 3 is structured by sequent~.aa.ly stackir~~ a gas diffusioxx layer 26 ancT a ct~talyst layer 29 from the outside to the e7.ectrolyte membrs.ne 'T side. The gas di-.~fusian i~tyer ~~r is foamed by mi~cii'rc~ a polytstrafluoxoe~trryl$ne dispers~.an l~.qua.d as a water.~a~epellent matex°ia1 and carbon bleak 24 (xe~ahen black EC (product name) 3.s used an the embodiment) ' as a~conduati.ve pcwdsr in carbon paper a~~s a conductive porous ~~xpport dipQed ~.n pc~lytetrailuoro~e~thylene as ~
water-repellent material to fill the sam~a as 3.n the ease of ' the anode 2.
w The eata~.yst layer ~T :Ls Formed by m~5.ng platinum black a.s .~ catalyst ps.rtiole with ~ wt% iNa~~.on (product aamr~) as a ration exchanger tc~ g~repare 'a cataly$t lager ink, r.~nd coating the catalyst l~eyesr inx on the gays diffusion layer ~6 by a screen pr~.ntinc~ nnethr~d..
=ncsideataily, ~t~ in the grewious cs,se~. t.'he catalyst lay$r ink is pz~ep8~re~d ss~ that a ~rrt~ight ratio b~atween the cas,ta,a,yst particle and the NafioxE. ( product n~un~s ) as the ration ao exck~anger can be catalyst : Nafion ( product name ) ~9 :1. .
Th$ cell. 10 a.s con~ttituted by holslin~ the electrolyte membrane 'T between the electrodes 2,~, arxd executing adhesa..vmnolding by hot pressing at abou'~ +150°C
while the electrc~c'i,as ~, ~ are held between the separatoxs 2S 8, 9.
Next, description will be made o~ a difference its, output between the cell 1i7 r~~ the embodiment and the -~sonventional call in which the mater-repellent material ~.s added to the gas diffusion layer o~ the ~~nt~de by referring t0 FIG. 4. F=t3. 4 is ti view sh.t~w3.ng a relat5.on 'between a curresnt ~.ne~ a voltage in each of the oall 10 of the e~eebod3.mer~t and the convex~,tiorsa~.~. cell. Fear the sell 1~D o~
the embO~diment, the call prepared in th~x aforementioned manner 3s us~d. For the convem.ty~nal .cell, . a. cr~l1 in wh~.csh an anode is constituted eimilar~.y to the cathode 3 of the c~mbodimen~t is need . That . zs~ , the conventional ce~.~, u$es the anC~da and the cathode in both Of which roister-rep~alleitt materials axe added t0 gas diffusion layers.
Inc3.dentally, . FIG. 4 shows measurement of pd~arer gen~sration charatsteristics at +6o°C by using a -meth~ol aqueous sohxt~.oa of a. ooncer~tration ~, mol/L as a ~.iquid final for $ach cell, ~tnd. supplying sti~c as an oxidant gas.
black Square indicates a measux~tng result of the sell 10 of the ~ embodiment , and s white sc~uarE~ indicates a. measuring remxlt of the conventional c~u~.~..
From the drawW rrg, it aan bs und~:rstood that poorer generation oharacterist~.cs ors high~a~ in .the cell. ~.U of the embodiment than that ixx the aonvent~.ona1 cell at a high current density. ~hi$ rnay be attributed. to improve~m~snts of supply eafficie~ncy of the liguid fuel in the anode 2 and disahaxge e~ff3oie5ncy of carbon da.oxide ges,erated ~.n the or9.talyst layer 21 over those Of' th$ convent~.on~al call.
Thus , iii the fbe3. call 1. the liq~y.ici fuel is supplirtsd to tk~e l~.quid fuel st~p~rly manifold. ~cef the cell l~ -unit 5, and ai.r is supplied to the oxidant gas supply manifold. Then, the liquid fuel sugpiiec~ to the liquid fuel. supply manifold is d~.~ltribute~i thr~augh eauka anode channel 11 to he supplied to the anode :~. Oa the other hand, the a1r supplied to the oxidant gas supply man~.fc~ld i$ supplied through each cathode channel 12 to the oa.~thOde 3. A superfluous gas is discharged from: the v~ci.dant .gas discharge man~.fp~d.~
i3er~ , for tine liqu~.dl fuel srup~al:yed to the anode 2 , ~.O ~~.nce - the carbon fibers 22 8f the gasp d:Lffus3.o~n i~.yer 20 axe coated with the hydxoghi~.~.c materials as described abtrv~s , a hollornt p,'xx't hs~v3.ng hydrophiliaity can be f orcned in the oarbox~ ~ f~.bax 22 near the surface of. the ;porous .suppoxt.
and a l~.qix~.d fuel passage C~a.xl be formed to supply the li.quira fuBl to the catalyst layer. 12 formed on the electrs~lyt~ membrane '~ side of the anode ~ 2 . ..~speci~tlly. by ~contaiaing 5 ~vt% to stt wt%, preferably e':W-~vt% ts~. 4Q arty, of the hydrophili~s material in the coaduotive porau~ Support c~oate~d, therewith as described above, it is possible to more 2o improve d~.ffu~ibility of the liquj.d fuel.
Aor.~~Gx'd3.ngiy, as irsdicate~d by a solid-line ai'~roar C~f FxG. ~, the liquid fuel permegte~s the porous support thz~r~txgh the liquid final passage. Then, aftex the Z3qu3d fuel is roughly un~.foxmly 8lffused through the ga$
diffusion layer 20, it permeates the cataly$t lrayer 2~, arsd srrode reaatioia ~.~ caused 'by a catalyst c~f the aata.lyst layer 21 to oxidise t.he~ l~.quid fuel ( ohenni~aaJl formula ( ~. ) ~ s CH30H-~HaU--YCtJZ+fiEI'"+6e- . . . ( 1 As indicated, b~,s a dotted-line arrow of FzG. 3, carbon dxaxide generated by the anode reaction in the catalyst layer 21 is di~charge~d tts the csutside through stn aperture ( smell ho1$ ~ in the structure df the carbon biacsk 24 as a conductive poarder fully s~uppl~.ed t~et~esrn the carbon fibers v2 of the gas c~i~~usir~n .layer 20. The apertuxe fozmad ire the carbaxx b~.aals 24 is not closed °by the permeation of th,e l3.quid fuel becsause ~.1: is small. A gas such as carbon d3.oxide gen~arate~d in the catalyst lever 21 cyan be easily d~.sch$rged tharethxaugh tt~ the outside .
Espea3.ally, accoacd~.ng tv the embsadimexxt. $ync$ the carbon blacx ~.2~i r~onta.n~xousyy fills the caxbon paper as the porous support frown its liquid fuel ~3upply side to the catalyst layex 21 side, a liquid film of the lic,~u.id fuel formed on the ~ liquid i~uel supply sides of the gas d~.ffusion layer 20 becson~s discn:r.txnuou~s. and a discharge passage of the aerbon dioxic~ generated in the catatys~t layer 21 can be sv~xwly obtainesd. Thus , ixtconven~.ence~ c~f staying of the 2o caxban dioxide generated in the gas di~~u$ion layer ~(~ wan be prevented. diff~ut~ribi~.ity of the l~.c~uid i'u~al in the anode 2 can be 3 mprvved, ~xono$ntratiQn p~rlarization of the liquid fuel in power generation canx be reduced, and perfQx-cnan~ce of the fu~sl ce3.1 1 scan therefore De improved. ~nc~.dent8~~.ly, the performance imprQVeament df thaw fuel cell 1 0~ the inveiat,~.on 3.$ also apparent Exam ~eua experiment x~sua.t ttf FIG. 4.
~laac~rd~.ng to the embod~.ment , far the carbon b~.ack Z4, by using r~x~rbon bleak whQ~3e ~iibnstylphthalate absorption is z60 ml/10~ g ax more, or 360 ml/~.d0 g ax nmrre, it is possible to secure s large aperture valurne i.n the structure c~f the aarban black. and to imprava dischas~ge efficiency of th~ carbon dioxide.ms~re.
Further:. acac~~rding to the embod3.ment, s.3.nae the o~atex-repellent material i.s added to this carbon black 24 as' desaribod - abo~re , it is poss3.ble to prevent iaaanvenienae of its closing of the 8yr~srture in the struc~tu5~e . the~rr~of by the liquid foal, and to smooth~.y discharge the carbon dioxide .
g~xrrerated .~.n the vataly~st layer ~~L through the apertures ~.n the struaturw of the carbon bleak 24 to the ou.ts~.de~.~ . . .
Maxecwe~r, it is possible to suppress a. ~:educt~.on in an .
x5 output of the fuel cell itself taaused by, c~onduGt~.vity di~r3.sion~. . .
Sspec~.ally, regarding the amc~uni, of the arater-repellent mat~rial added, to the Caz~ban black ~4, S v~t% to 8t1 a~tt%, pr~3ferably 2Ct wt% ts~ 40 wt%, of the water-repellent 20 material is added with x~aspeGt to the sum total of the ao~tduGtive porous support and the water-repellent material.
~rocordingly, it is pc~ssib~.e to 3:mprove discharge effic3~ex~cy trf the aarboa dioxide generated ire. the cata3.yst layer 21.
A ,proton generated by the a..forc~mentioned anode 2S rear~tion causes o~cidation reduction reaction with oxygen ( oxidant gas ) conta3.n~sd a.n the air supplied to fihe c~dthode in the elevtrolyts me~ebr~,xse 7 to generates gowex ( chemical - Z~ -formula: (2)). =nci8entally, this power generated here is contrt~llad b~,r a control device (not shoe) as contxol means for poorer generation .
3/20Z.rtSFi~+6e--~~I~a~ . . . ( 2 Hy flee . aforementioned constitut~.on, acc~c~rding to the embodiment. the liquid fuel supplied to the anodd 2 can bs uniformly d;3.f~ussd in the gas diffu~~.c~n layer 2(? through the hyc'ixoQhilio liquid fuel pa$sage~ nee=: the surface of the porou$ support which constitutes the gays diffus~.ra~n layer 20 1o to permeate the catalyst layer 21. Thug, concentration po~.~isat3.on of the ~ liquid f~ac~i is reduced to enahle improvement of the performance of tk~.e f~;~el csl~.. ' . ..
Additionally, since the apartura~ formed xn the poro~.as~ support is fx~-~-ed w5.th th~ conductive poa~t~,er to which the water-'reQellent material is added, it is possible to discharge the oeu~bon dioxide generate6 in the Catalyst layer 21 to ~ the outside through the s~mal.l ~ hole :formesd xn .
the coaduotive po~rder. .~cco~cdingl3r, it is goss3,ble to reduo~e the concentration ~olar3.xation of the liqu3.d fuel in 'the anode 2.
Acaarding to the embodiment. slues they carbon black 24 to which then water-repel~.e~nt material is added fillss the' conducta.~re~ porous support by 5 mg/cmx, the eonduat3.ve powder can be present Exam the catalyst layex 21 .25 side o~ the gas dif~usi.on lager 20 to the opposite side.
fih$ liquid film of the liquid fuel formed nn the liquid fuel supply s3.de of the gas di.ffu~ion a~.'yar 2p t~ecomes disaontinuoos . Thus . ~.t is possible to ob!tx~~.ri. th$
discharge passage of the Garbtsn dioxide generated in the oatalyst layer ~~. more surely.
Incidentally, according to t~xe ~~c~tbodiment , the carbon blaoJc 24 to whioh the waterre~pe~7llent material is W added fills the couduot~.ve porous suppt~~.~~t by about 5 rng/cm2. w However, by setting the ams~unt. eaf cs,rbon black 24 to x mg/om2 tc~ 20 m~.~''~can2, the Carbon bZs.~c7e ~4 os.n beg gropexly present in the gas d~.ffusiow layex 20 from the ~ oatalyst layer 21 s3.de thereof to~the opposite side.
Additsonally, it is possi'61e to prevent closing elf the .
aperture of the porous support caused by filling with .
excessive carbon black 24. lens a r$s~tlt, it ~~.$ possible to prevent 3.nterference ar~.th diffusion of tk~e liquid fuel.
. ~. According ao the em'bod,iment . the carbon paper is use~d.~s the conductive porous support. =n addition to this. a carbon f~.ber of unwoven cloth, aroven carbon cloth, or a metal mesh such as a platirwun mesh or a gold-coated coppex mesh map be used.
AGCOrding to tl~e embodiment , they polyv3.ny1 alcohol.
is used as the hydrophil~.c material coated an the carbon paper. =n addition tee this, palyv~.ny1 pyr~ra~.idone.
pa~.ybE~naimidazole, colloidal ~oili~aa, tit~an3,unn oxide or ~eosite may be used.
2s =n t~rder to prr~v~.de~ more urr~.fc~rrtt hydrophiliaaty 'to the, conductit~e porous supgort , a ~aalymer~isa mater3.sv1 .among hydrophilic mater3.e~.1$ is preferably used,. Further.
regarding the a$dit~.on amount of the hydroph.il3.c~ material.
by setting a weight ratio to ~ wt% to 61~ wt%. preferably 20 wt% to 40 wt%, with respect to they aonc3uative porous support coated vo~ith the hydro$hil~.G material as described above, it is pcr~ss3ble t4 improve d~.ffu~s,3b~.13,ty at the liguid fuel mofie .
Wurther, according to the bmbodime~nt, the 7~eohen bXaols EG ( product name j .is used as the rsonduvtive paroo~der.
Xn addition to this, other carbon blaclG such as harness 1~D black ore acetylene black may be used- :tn such a case; in order to improve dischar$e efficiency of the aarban dioxide generated 3.n the c~atal~rst layer ~~, s3.mi:L~arly~ to the . embo~d~.ment, s, larger aperture volume is prefearabz~a in a struCture~ of the conduCStive carba~n bla~.~
~'urtlaex~re , aacarding ~O they embodiment , the . .
polytetrafluoroethylene is used as th$ w~rater-repell$nt ~nateria~. added to the carbon b~.ack 24. Tn ae~ditian tc~
this. a fiuororssin such as a tetrc~fluox:aethylen~r-perf3.u~rroallcylvinyl ether aeapolymer, a 20 tetrafluoroethyyler~e-b.~dx.~fluoropropylenes ot~polymer, a polyvinylidene flucxride, polyfluorc~v3.nyl, p~e~fluoroalkoxy, tetrafluraethylene-ethylene copolymer.
polychlorotrifluoroethylene, or poye~htersulfrrne may b$
urea.
25 AGCOrding to the embt~c~.iment, they two~eloment a3.loy ~of the p~.atin~.un-swtheni~sm blacslC is ~.ase~el as the Catalyst particle ref the os7~talyst layer ~7. of the anode 2 , Tn -addition to thi$, a twro-element alloy ojE platimua~-molybdenun~. g~.at~-nr~m-iridium, platinum.-tin, platipum-tungsten, glatinuu~-'~it,an~.tvm~ or glatiriura-xhodium, or a multielsment alloy of three elements or more wh~.ah oambine such elements may be used. Additionally, a ~satalyst metal which caxri~es carbon bleak may be used.
Furtheza~nore, ~ a.oooxding to the ernbod~ant , the platir~um black 3s used as the cata~.,yst psrtial~ of the catalxst l~xy~sr 27 of the cathode 3. In addition to this, a 1t1 oannb3.natior~ of alloys which constitute the catalyst .. $,~iclt~a e3~ the catalyst layem 21 of the ,anode 2, or a catalyst metal which aaxriss caxbcn b~.ac:lc m$y be us~ad.
Iat~~.denta3.ly, according to they tumbodiment , the methana~. and the DMB are cx.ted ~s the liguid fuel.
~iawewex, similar effects oan be , axhibitt~d evc~ri by other ~.iqu~.d fuel such as pxopar~oi, butanal. trimethvxymethane, , .
e~thylene~ glycol, dr ad. f~rrmic acid. lsrCCOrding to the e~nnbodicnent , the s:3.r is cited as the oxidant gas . I3owever.
similar effects oars be exh~,.bited. by oxygen, a. hydrogen 2o peroxide solution or the l~.lce , discussed above irr detail, acaord~..ng to the present in~rention, the furt~s cell comp~cises the anode and -the cathode on both suxfaaes of the electrolyte membrane, supglies the lisZu~.cY. fo.e1 to the made. wu.pp3.i~~ss the oxidant gas to the cathod~ , atxd reacts thEe i~.c~ui~d fuel nrith the oxidant gas to s,~enesrate power . The anode oo~pris~s tht~ r~a,s diffusion layer coristitutod by filling the conductive porous support ~rh~.ch is coated with they hydrophilic material with the conductive powder, and -Che aata~.xst lager. Thus. the hydrophil3.c hollow part is formed near the surface of they porous sup~rcrrt of the gs.s diffusion layer, and the liquid fu~sl ~rassage can be formed to supply the l~.~uic~ fuel to the cat~xlyst 7.aye~r formed as the electrolyte mem'~srane sides of the anode .
The,ape~rture formed in the porous sugport is fihe~d w3.th the t~onduative gawdar. ln. thxs Casks, however, 3.d the smalx ho~.e is for~necl in the conductive powder. Thus, szno~ the small holm ~is not closed by, 1~'.he liquid fuel, a gas such as carbon dioxide generated in the catalyst layer 'aan be disch8~xged to the outside.
Therefore, concentration polarisation of the I5 l3.qu3d fuel in the anode ~.s reduCeB to enable .output .
improvement of the fuel ce~.l. .
Mere . the ptrxatts suppt~rt is made of carbon f ibexs .
Thus, they $orou~a support haviac~ an apar~:u~ee can be easily ooris~t~.tuted to improve productivitg.
fit! Add~.tiaaally, the gas d3ffvxs~.an Layer c3ontains 5 wt~ to 6o vot% of the hpdroph~.l~.o material with resgeat to the sum total of the ~:onduot~.v$ porous supgort and th~a hydrophilic material. ~cooxdingZy, diffusibility of the liqui.$ fu~ai oaa b$ improved more. Further, the gas diffu$ion 3.ayBr cbz~tains ZO wt% to ~O wt% of the hydrophilic material with resgoct to the sum total. of the aonduct~.ve porQUS ~sugpart and the hydrophilic material.
Accordingly, the tiif~u9sb3.13.'ty of the liquid ~uel Can be itnpraved mush mare .
In the foresgQing , the tsonduative powder is the carbon black. Thin, discharge efficiency ~o~ the carbon dioxide generated 3.n the catalyst layer can be improved.
Bspecia.l.ly, by wsiri~g they carbon blac% whose dibutylphthalate absorption is 7.60 mll100 g or more, or 360 mlJl~DO g or more,, a large aperture volmme can be seaurad is the . struatu~e of the ca:c'bcan ~ria~slc. Thus, it is ~ possible to 14 improve the discharge eatficiency o~ the aarboa dioxide mox~ . , . .
In each of .the aforemax~t3.orred ixaventio~as , the water-rege~.3ent material is added to the carbon biac7s.
Ac~aoardingly, it . is pass~.bie to pr$ven~t :~ria~rlavenisnoe Of Z5 a~.osir~g of the ape~acture i.n the strucstur~s of the carbon bl.acsiE Gausee~ by the i.iquid fuel. x'hus, it is posss~.b~,e ~C~a smra~othly discharge the carbon dic~xi.de generated in th~a...
aata.lyst layer to the outside through the aperture in the structure of trie carbon bxaCl~.
24 especially, 5 wt% to 80 wt% of i~h~r water-repellent materis.7. is add~ad to the Carbon black r~rith respwct to the sum total of the canduative porous support and the water-repeller~t material.. Further. ZO avt% to 40 wt% of tJla.~e crater-repellent material is adc'L~sd to the carbon black with 25 respect tQ the snm total of the Goriduative porous support oat! the wste~r-~repe~.leri.t mater3,al . ~.'hus , ~.'~ ~.s possiblev tcs ~.cnprove the dis~aharge efficiency of the carbon d~oxida -generated in the G~.talyst laxer.
Hy adding the water-repel7~ar~t ~riaa,terial to the carbon. black as descr~.bed above, it ~.s possible to supp~eess a reducstion in as out~sut oaf the fuel cell . itself' caused by conduativa.ty division.
Fuxther, the carbr~n black is present from the catalyst ~.a~rer side of the gas diffusion ~.ayer . to the oggo$ite side. Accordingly, the liqu3.d film of the 13.q~s~.d fu$3, formed on the ~l~.quid fuel ssupply s~.de of the gas 1o diffus~.on layer becoms~s dis~aontinuous, and it is possible to surely o'bt~ain the discharge pasrsage of . the t~arbQn 'dioxide generated in the aataiyst layer. w ~h~refare. it i:~ passibl~: to suppress ..
.in~onvenieace of alosiag of the os.rboa dioxide generated in 25 trie catalysst layer ix~ the anode, to impxove diffusibility of the liqix~.d fuel in the anode . aad to redua~e .
concer~tz~atiQr~ polariaatxc~n of the liquid. fuel in power generation, thereby i:mpro~r~.ng the pe~efo=:manc~a of the fuel coli.
2D Furthermore, aCCOrding to the isventian, 3.n th$
foregoing, by setting the amount of cs.rbon black f~.~.ling the gas d~iffusxc~n laye~c to Z mg,lema to 20 mg/csna, the carbon bleak ~san ba properly present in the gas diffusion lager from the catalyst layer' side there~rf tt~ the opposite 25 side . Additiona,Xiy, ~.t is possibhs to prevent closing c~f the aperttxxw ref the pc~roo.s scupport caas~ed by fi~.~.~.ng with ~xC~assive cnrtloxi black. As a result; it ~,s po$sible to Q~~vesnt interfersr~~e wii~h d3.~~usia~a of the lic~id fuel.
Claims (12)
1. A fuel cell which comprises an anode and a cathode on both surfaces of an electrolyte membrane, supplies a liquid fuel to the anode, supplies an oxidant gas to the cathode, to react the liquid fuel with the oxidant gas and to generate power, wherein the anode comprises a gas diffusion layer constituted by filling a conductive porous support which is coated with a hydrophilic material with a conductive powder, and a catalyst layer.
2. The fuel cell according to claim 1, wherein the porous support is made of carbon fibers.
3. The fuel cell according to claim 1 or 2, wherein the gas diffusion layer contains 5 wt% to 60 wt% of the hydrophilic material with respect to a sum total of the conductive porous support and the hydrophilic material.
4 . The fuel cell according to claim 1 or 2, wherein the gas diffusion layer contains 20 wt% to 40 wt%
of the hydrophilic material with respect to a sum total of the conductive porous support and the hydrophilic material.
of the hydrophilic material with respect to a sum total of the conductive porous support and the hydrophilic material.
5. The fuel cell according to one of claims 1 to 4, wherein the conductive powder is carbon black.
6. The fuel cell according to claim 5 wherein a water-repellent material is added to the carbon black.
7. The fuel cell according to claim 6, wherein 5 wt% to 80 wt% of the water-repellent material with respect to the sum total of the conductive porous support and the water-repellent material is added to the carbon black.
8. The fuel cell according to claim 6, wherein 20 wt% to 40 wt% of the water-repellent material with respect to the sum total of the conductive porous support and the water-repellent material is added to the carbon black.
9. The fuel cell according to one of claims 5 to 8, wherein a dibutylphthalate absorption of the carbon black is 160 m1/100 g or more.
10. The fuel cell according to one of claims 5 to 8, wherein a dibutylphthalate absorption of the carbon black is 360 ml/100 g or more.
11. The fuel cell according to one of claims 5 to 10, wherein the carbon black is present from the catalyst layer side of the gas diffusion layer to an opposite side thereof.
12. The fuel cell according to ones of claims 5 to 11, wherein an amount of the carbon black with which the gas diffusion layer is filled is 1 mg/cm2 to 20 mg/cm2.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2003138559A JP4293831B2 (en) | 2003-05-16 | 2003-05-16 | Fuel cell |
| JP138559/2003 | 2003-05-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2467311A1 true CA2467311A1 (en) | 2004-11-16 |
Family
ID=33028412
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002467311A Abandoned CA2467311A1 (en) | 2003-05-16 | 2004-05-14 | Fuel cell |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US20040247992A1 (en) |
| EP (1) | EP1478041A3 (en) |
| JP (1) | JP4293831B2 (en) |
| KR (1) | KR100594540B1 (en) |
| CN (1) | CN100421293C (en) |
| CA (1) | CA2467311A1 (en) |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101181852B1 (en) * | 2005-01-26 | 2012-09-11 | 삼성에스디아이 주식회사 | Membrane-electrode assembly and fuel cell system comprising the same |
| JP2006252908A (en) * | 2005-03-10 | 2006-09-21 | Konica Minolta Holdings Inc | Fuel cell |
| JP4949655B2 (en) | 2005-08-09 | 2012-06-13 | 株式会社日立製作所 | FUEL CELL, FUEL CELL POWER SUPPLY SYSTEM, AND ELECTRONIC DEVICE USING THE SAME |
| JP4643393B2 (en) * | 2005-08-24 | 2011-03-02 | 株式会社日立製作所 | Fuel cell |
| JP4643394B2 (en) * | 2005-08-24 | 2011-03-02 | 株式会社日立製作所 | Fuel cell |
| EP1780822B1 (en) | 2005-11-01 | 2012-01-18 | Tomoegawa Co., Ltd. | Gas diffusion electrode, membrane-electrode assembly, polymer electrolyte fuel cell, and methods for producing |
| WO2007078771A2 (en) * | 2005-12-15 | 2007-07-12 | Hollingsworth & Vose Company | Fuel cell gas diffusion articles |
| KR100691453B1 (en) | 2005-12-21 | 2007-03-12 | 삼성전기주식회사 | Flexible Fuel Cell |
| KR100781482B1 (en) * | 2005-12-22 | 2007-12-03 | 산요덴키가부시키가이샤 | Fuel cell |
| KR100837395B1 (en) * | 2005-12-28 | 2008-06-12 | 삼성에스디아이 주식회사 | Fuel composition for fuel cell and fuel cell using the same |
| CN100472872C (en) * | 2006-02-01 | 2009-03-25 | 松下电器产业株式会社 | Direct oxidation fuel cell and method of operating a direct oxidation fuel cell |
| JP5151217B2 (en) * | 2007-04-03 | 2013-02-27 | 株式会社日立製作所 | Fuel cell |
| KR100881366B1 (en) * | 2007-09-18 | 2009-02-05 | 주식회사 진우엔지니어링 | Gas diffusion layer for fuel cell and fuel cell electrode using same |
| US20090104476A1 (en) * | 2007-10-17 | 2009-04-23 | Gm Global Technology Operations, Inc. | Fuel cell stack with asymmetric diffusion media on anode and cathode |
| JP2010153145A (en) * | 2008-12-24 | 2010-07-08 | Toshiba Corp | Anode electrode for direct-methanol fuel cells, and membrane-electrode complex and fuel cell using the same |
| KR101639783B1 (en) * | 2009-02-03 | 2016-07-15 | 주식회사 동진쎄미켐 | Method for preparing gas diffusion layer for fuel cell, gas diffustion layer prepared by the method, Electrode and Fuel cell comprising the same |
| EP2483959B1 (en) * | 2009-09-25 | 2015-02-11 | Danmarks Tekniske Universitet - DTU | Method of operating a direct dme fuel cell system |
| EP2875541B1 (en) * | 2012-07-19 | 2017-04-19 | Audi AG | Microporous layer with hydrophilic additives |
| WO2014119927A1 (en) * | 2013-01-29 | 2014-08-07 | 지브이퓨얼셀 주식회사 | Fuel-cell cell production method |
| WO2014119929A1 (en) * | 2013-01-29 | 2014-08-07 | 지브이퓨얼셀 주식회사 | Method for fabricating cell for fuel battery |
| CN111244476B (en) * | 2018-11-28 | 2021-11-02 | 中国科学院大连化学物理研究所 | Hydrophilic treatment method of carbon paper for fuel cell and application thereof |
| EP4113670A4 (en) * | 2020-02-25 | 2024-01-10 | University of Yamanashi | GAS DIFFUSION ELEMENT, GAS DIFFUSION UNIT AND FUEL CELL |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5358640A (en) * | 1976-11-05 | 1978-05-26 | Fuji Electric Co Ltd | Fuel cell |
| FR2383215A1 (en) * | 1977-03-09 | 1978-10-06 | Ugine Kuhlmann | HIGH ELECTRIC CONDUCTIVITY AND HIGH ABSORBENT ACETYLENE BLACK |
| US4283378A (en) * | 1979-08-01 | 1981-08-11 | Cabot Corporation | Production of high surface area carbon blacks |
| JPS5768142A (en) * | 1980-10-14 | 1982-04-26 | Hitachi Ltd | Electrode catalyst for fuel cell and its production |
| JPS5782971A (en) * | 1980-11-12 | 1982-05-24 | Hitachi Ltd | Production of electrode for fuel cell |
| JP3444541B2 (en) * | 1992-08-24 | 2003-09-08 | 株式会社東芝 | Polymer electrolyte fuel cell |
| US5773162A (en) * | 1993-10-12 | 1998-06-30 | California Institute Of Technology | Direct methanol feed fuel cell and system |
| JP3331706B2 (en) * | 1993-11-08 | 2002-10-07 | 株式会社豊田中央研究所 | Fuel cell |
| JP3583897B2 (en) * | 1997-04-11 | 2004-11-04 | 三洋電機株式会社 | Fuel cell |
| US6103077A (en) * | 1998-01-02 | 2000-08-15 | De Nora S.P.A. | Structures and methods of manufacture for gas diffusion electrodes and electrode components |
| CN1516311A (en) * | 1998-06-16 | 2004-07-28 | ���µ�����ҵ��ʽ���� | polymer electrolyte fuel cell |
| GB9905950D0 (en) * | 1999-03-16 | 1999-05-05 | Johnson Matthey Plc | Substrates |
| EP1265303B1 (en) * | 2000-03-07 | 2009-07-01 | Panasonic Corporation | Polymer electrolyte fuel cell and method of manufacturing the same |
| US20020155341A1 (en) * | 2001-04-19 | 2002-10-24 | More Energy Ltd. | Self-managing electrochemical fuel cell and fuel cell anode |
| US6821661B2 (en) * | 2001-08-31 | 2004-11-23 | Plug Power, Inc. | Hydrophilic anode gas diffusion layer |
| JP3941444B2 (en) * | 2001-09-28 | 2007-07-04 | 日産自動車株式会社 | Fuel cell separator |
-
2003
- 2003-05-16 JP JP2003138559A patent/JP4293831B2/en not_active Expired - Fee Related
-
2004
- 2004-05-14 US US10/845,593 patent/US20040247992A1/en not_active Abandoned
- 2004-05-14 CN CNB2004100433254A patent/CN100421293C/en not_active Expired - Fee Related
- 2004-05-14 EP EP04011523A patent/EP1478041A3/en not_active Withdrawn
- 2004-05-14 KR KR1020040034155A patent/KR100594540B1/en not_active Expired - Fee Related
- 2004-05-14 CA CA002467311A patent/CA2467311A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| US20040247992A1 (en) | 2004-12-09 |
| CN1551392A (en) | 2004-12-01 |
| JP4293831B2 (en) | 2009-07-08 |
| JP2004342489A (en) | 2004-12-02 |
| KR100594540B1 (en) | 2006-06-30 |
| EP1478041A3 (en) | 2007-07-11 |
| EP1478041A2 (en) | 2004-11-17 |
| KR20040099149A (en) | 2004-11-26 |
| CN100421293C (en) | 2008-09-24 |
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