JP4015913B2 - Single cell for solid oxide fuel cell and fuel cell using the same - Google Patents
Single cell for solid oxide fuel cell and fuel cell using the same Download PDFInfo
- Publication number
- JP4015913B2 JP4015913B2 JP2002279950A JP2002279950A JP4015913B2 JP 4015913 B2 JP4015913 B2 JP 4015913B2 JP 2002279950 A JP2002279950 A JP 2002279950A JP 2002279950 A JP2002279950 A JP 2002279950A JP 4015913 B2 JP4015913 B2 JP 4015913B2
- Authority
- JP
- Japan
- Prior art keywords
- solid electrolyte
- layer
- electrolyte layer
- fuel cell
- unit cell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000446 fuel Substances 0.000 title claims description 108
- 239000007787 solid Substances 0.000 title claims description 28
- 239000007784 solid electrolyte Substances 0.000 claims description 136
- 238000006243 chemical reaction Methods 0.000 claims description 113
- 239000000758 substrate Substances 0.000 claims description 68
- 230000002265 prevention Effects 0.000 claims description 29
- 238000010304 firing Methods 0.000 claims description 24
- 229910052727 yttrium Inorganic materials 0.000 claims description 24
- 239000003566 sealing material Substances 0.000 claims description 18
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical group O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 16
- 229910052706 scandium Inorganic materials 0.000 claims description 15
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 14
- 239000012528 membrane Substances 0.000 claims description 10
- 238000007789 sealing Methods 0.000 claims description 3
- 238000005304 joining Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 description 19
- 238000010248 power generation Methods 0.000 description 19
- 230000000052 comparative effect Effects 0.000 description 16
- 239000000463 material Substances 0.000 description 15
- 238000011156 evaluation Methods 0.000 description 13
- 239000002002 slurry Substances 0.000 description 13
- 239000007789 gas Substances 0.000 description 11
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 10
- 239000000843 powder Substances 0.000 description 10
- 238000000034 method Methods 0.000 description 9
- 230000002093 peripheral effect Effects 0.000 description 9
- 239000011521 glass Substances 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 8
- 239000002184 metal Substances 0.000 description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 8
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- 229910052760 oxygen Inorganic materials 0.000 description 7
- 239000001301 oxygen Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 6
- 239000000956 alloy Substances 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 239000002737 fuel gas Substances 0.000 description 6
- 239000007800 oxidant agent Substances 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 6
- 229910002076 stabilized zirconia Inorganic materials 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 5
- -1 cermets) Chemical compound 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 229910052759 nickel Inorganic materials 0.000 description 5
- 229910052697 platinum Inorganic materials 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 239000004372 Polyvinyl alcohol Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 150000002430 hydrocarbons Chemical class 0.000 description 4
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 229920002451 polyvinyl alcohol Polymers 0.000 description 4
- OAYXUHPQHDHDDZ-UHFFFAOYSA-N 2-(2-butoxyethoxy)ethanol Chemical compound CCCCOCCOCCO OAYXUHPQHDHDDZ-UHFFFAOYSA-N 0.000 description 3
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 229910052684 Cerium Inorganic materials 0.000 description 3
- 206010021143 Hypoxia Diseases 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 229910052772 Samarium Inorganic materials 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007772 electrode material Substances 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 229910052746 lanthanum Inorganic materials 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 229910052712 strontium Inorganic materials 0.000 description 3
- 229910052688 Gadolinium Inorganic materials 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 2
- 229910000420 cerium oxide Inorganic materials 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 239000011812 mixed powder Substances 0.000 description 2
- 229910000480 nickel oxide Inorganic materials 0.000 description 2
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 2
- UPWOEMHINGJHOB-UHFFFAOYSA-N oxo(oxocobaltiooxy)cobalt Chemical compound O=[Co]O[Co]=O UPWOEMHINGJHOB-UHFFFAOYSA-N 0.000 description 2
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 229910002077 partially stabilized zirconia Inorganic materials 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- 229930195734 saturated hydrocarbon Natural products 0.000 description 2
- 239000010944 silver (metal) Substances 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910001233 yttria-stabilized zirconia Inorganic materials 0.000 description 2
- 229910002761 BaCeO3 Inorganic materials 0.000 description 1
- 229910002976 CaZrO3 Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910002439 Ce0.8Sm0.2O1.9 Inorganic materials 0.000 description 1
- 229910002438 Ce0.8Sm0.2O2 Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229910002138 La0.6Sr0.4CoO3 Inorganic materials 0.000 description 1
- 229910002331 LaGaO3 Inorganic materials 0.000 description 1
- 229910002328 LaMnO3 Inorganic materials 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 241000968352 Scandia <hydrozoan> Species 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 229910003408 SrCeO3 Inorganic materials 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 229910000421 cerium(III) oxide Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007606 doctor blade method Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 239000002241 glass-ceramic Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 229910001026 inconel Inorganic materials 0.000 description 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 1
- 229910002075 lanthanum strontium manganite Inorganic materials 0.000 description 1
- 239000011344 liquid material Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Inorganic materials O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 150000002902 organometallic compounds Chemical class 0.000 description 1
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 description 1
- HJGMWXTVGKLUAQ-UHFFFAOYSA-N oxygen(2-);scandium(3+) Chemical compound [O-2].[O-2].[O-2].[Sc+3].[Sc+3] HJGMWXTVGKLUAQ-UHFFFAOYSA-N 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 239000011214 refractory ceramic Substances 0.000 description 1
- 239000003870 refractory metal Substances 0.000 description 1
- 229910001954 samarium oxide Inorganic materials 0.000 description 1
- 229940075630 samarium oxide Drugs 0.000 description 1
- FKTOIHSPIPYAPE-UHFFFAOYSA-N samarium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[Sm+3].[Sm+3] FKTOIHSPIPYAPE-UHFFFAOYSA-N 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Inorganic materials [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 description 1
- 229910014031 strontium zirconium oxide Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229930195735 unsaturated hydrocarbon Natural products 0.000 description 1
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Fuel Cell (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は固体電解質型燃料電池用単電池及びこれを用いた燃料電池に関する。更に詳しくは、燃料極を基板として用いる支持膜式構造であり、固体電解質層と空気極と間に反応防止層を備える固体電解質型燃料電池用単電池及びこれを用いた燃料電池に関する。
【０００２】
【従来の技術】
平板型の固体電解質型燃料電池用単電池（以下、単に「単電池」ともいう）は発電性能のうち特に体積効率に優れており、この単電池を積層した実際の固体電解質型燃料電池（以下、単に「ＳＯＦＣ」ともいう）の実用化が期待されている。単電池は一般に少なくとも燃料極、固体電解質層及び空気極の３つ部分がこの順に積層された構造を有し、各層の厚みによって自立膜式と称されるタイプと支持膜式と称されるタイプに分けられる。このうち自立膜式の単電池は、固体電解質層が自立可能に厚膜化され、その厚膜表面に他の部分が薄膜積層された構造を有する。一方、支持膜式の単電池は、空気極又は燃料極が自立可能に厚膜化され、その厚膜表面に固体電解質層及び他方の電極が薄膜積層された構造を有する（例えば、特許文献１参照。）。上記の単電池が要する３つの部分では固体電解質層の電気抵抗は他の部分に比べて遥かに大きい。更に、この固体電解質層の電気抵抗を下げるためには高温に加熱保持する必要がある。このため、固体電解質層を薄膜化できる支持膜式の単電池は、自立膜式の単電池に比べて効率面で大きなメリットを有する。
【０００３】
この支持膜式の単電池では、空気極にはＡサイトの一部をＳｒで置換したＬａＭｎＯ３系酸化物、固体電解質層にはイットリア安定化ジルコニアが多用されている。しかし、ＬａＭｎＯ３系酸化物とイットリア安定化ジルコニアとは反応性が高く、製造時に空気極と固体電解質層との界面に高抵抗の反応相が生成し、電池の出力が低下するという問題がある。これに対して、酸化セリウムを主成分とした反応防止層を空気極と固体電解質層との間に形成することで問題を解決しようとする技術が知られている（例えば、特許文献２参照。）。
【０００４】
【特許文献１】
特開２０００−２６０４３６号公報
【特許文献２】
特開２００１−２８３８７７号公報
【０００５】
【発明が解決しようとする課題】
上記特許文献２では、反応防止層の大きさや、セパレータとの関係については検討されていない。更に、より優れた発電性能を発揮できる単電池等が求められている。
本発明は上記に鑑みて成されたものであり、反応防止層の割れや剥がれを生じ難く、固体電解質型燃料電池とした場合にセパレータと単電池とのシール部における信頼性が高く、優れた発電性能を発揮できる固体電解質型燃料電池用単電池を提供する。また、この単電池を用い、信頼性が高く、より優れた電池性能を発揮できる固体電解質型燃料電池を提供する。
【０００６】
【課題を解決するための手段】
本発明者らは、反応防止層が形成された単電池等について検討した。その結果、固体電解質層（図３の１２）と面積が同じであるか又はそれより大きい反応防止層（図３の１３）を備える単電池（図３参照）や、燃料極層（図４の１１）と固体電解質層（図４の１２）との積層体の全面に反応防止層（図４の１３）がコーティングされた単電池（図４参照）は、端面に反応防止層が露出しているため、取り扱いを慎重にしないと反応防止層の角部からクラックを生じたり、割れを生じたりすることがあった。
また、これらの単電池を使用したＳＯＦＣでは、発電性能が理論値を大きく下回り、性能が十分に発揮されない場合があることが分かった。
更に、これらの単電池を製造する場合、反応防止層が他部に比べて焼成収縮率が小さいため、燃料極基板及び固体電解質層と同時焼成すると、反りを生じ易く、また、反応防止層の角部からクラックや割れを生じる。このため、従来は燃料極基板及び固体電解質層を焼成した後に、別工程で反応防止層を形成しており、製造に手間を要した。
そして、これらの多くの課題の全ては、反応防止層を固体電解質層よりも小さく形成することにより極めて効果的に解決されることを見出し、本発明を完成した。
【０００７】
本発明は以下に示す通りである。
本発明の単電池は、燃料極基板と、該燃料極基板の一面側に形成された固体電解質層と、該固体電解質層の該燃料極基板の対面側に形成された空気極層とを備え、且つ該固体電解質層と該空気極層との間に、ＣｅＯ２の一部のＣｅが希土類元素（Ｃｅ、Ｓｃ及びＹを除く）、Ｓｃ及びＹのうちの少なくとも１種により置換されたＣｅＯ２系酸化物からなる反応防止層を備える支持膜式固体電解質型燃料電池用単電池であって、上記反応防止層は、上記固体電解質層より面積が小さいことを特徴とする。
また、上記反応防止層の面積は、該固体電解質層の面積の２５〜９０％であり、且つ、上記空気極層の面積は、該反応防止層と同じあるか又は該反応防止層よりも小さいものとすることができる。更に、上記固体電解質層は、Ｙ、Ｓｃ及び希土類元素（Ｙ及びＳｃを除く）のうちの少なくとも１種により安定化されたジルコニアとすることができる。また、上記燃料極基板となる未焼成シート又は上記燃料極基板となる仮焼体と、上記固体電解質層となる未焼成固体電解質層と、上記反応防止層となる未焼成反応防止層とをこの順に備える未焼成積層体を形成し、その後、該未焼成積層体を一体に焼成する工程を経て得ることができる。
【０００８】
本発明の固体電解質型燃料電池は、本発明の単電池と、該固体電解質型燃料電池用単電池の上記空気極層側に設けられたセパレータと、該固体電解質型燃料電池用単電池と該セパレータとを気密に接合するシール部とを備える単電池ユニットが複数積層されて備えられた固体電解質型燃料電池であって、上記セパレータは、上記シール部を介して上記固体電解質型燃料電池用単電池が備える上記固体電解質層に接合されていることを特徴とする。
また、上記シール部は、ガラス質シール材及び金属質シール材のうちの少なくとも一方からなるものとすることができる。更に、上記固体電解質層の上記セパレータと接合される部位は、該固体電解質層の他部に比べて厚くすることができる。
【００１０】
【発明の効果】
本発明によると、ＳＯＦＣにおけるシール部付近の気密の信頼性が高く、優れた発電性能を得ることができる。
また、反応防止層の面積が固体電解質層の面積の２５〜９０％であり、且つ、空気極層の面積が反応防止層と同じであるか又は反応防止層よりも小さい場合は、特に優れたシール部付近の気密の信頼性と、優れた発電性能とを得ることができる。
更に、固体電解質層がＹ、Ｓｃ及び希土類元素（Ｙ及びＳｃを除く）のうちの少なくとも１種により安定化されたジルコニアである場合は、特に優れた発電性能を得ることができる。
また、所定の製造方法により得られた単電池である場合は、反応防止層の緻密度がより高く固体電解質層と空気極層との反応を確実に防止することができる。
本発明の固体電解質型燃料電池によると、シール部付近の気密の信頼性が高く、優れた発電性能を得ることができる。
また、シール部がガラス質シール材及び金属質シール材のうちの少なくとも一方からなる場合は、シール部における信頼性を特に優れたものとすることができる。
固体電解質層の上記セパレータと接合される部位が固体電解質層の他部に比べて厚い場合は、固体電解質層とシール部との反応により形成される反応層が固体電解質層を貫通して形成されることを防止でき、シール部における気密の信頼性が特に高く、優れた発電性能を得ることができる。
【００１１】
【発明の実施の形態】
本発明について以下詳細に説明する。
［１］単電池
上記「燃料極基板」は、水素源となる燃料ガスに晒され、ＳＯＦＣにおける負電極として機能するものである。また、少なくとも固体電解質層（通常、空気極層及び反応防止層も支持する。）を支持するものである。この燃料極基板を構成する燃料極材料は特に限定されず、各種の燃料極材料を用いることができる。例えば、Ｐｔ、Ａｕ、Ａｇ、Ｐｄ、Ｉｒ、Ｒｕ、Ｒｈ、Ｎｉ及びＦｅ等の１種の金属又は２種以上を含む合金、これらの金属又は合金とＺｒＯ２系酸化物（安定化ジルコニア、部分安定化ジルコニア等を含む）、セリア及び酸化マンガン等のセラミックとの混合物（サーメットを含む）、及びこれらの金属のうちのＮｉ及びＦｅ等の金属の酸化物（ＮｉＯやＦｅ２Ｏ３等）とＺｒＯ２系酸化物（安定化ジルコニア、部分安定化ジルコニア等を含む）、セリア及び酸化マンガン等セラミックとの混合物等を挙げることができる。これらの燃料極材料の中でも、酸化ニッケル（作動時には還元されてニッケルとなる。）とＺｒＯ２系酸化物との混合物が好ましく、更には、ＺｒＯ２系酸化物がイットリア及び／又はスカンジアにより全部又は一部が安定化されたジルコニアであることが好ましい。これらは燃料極基板としての電気的性能や機械的強度をバランスよく合わせ持つからである。
【００１２】
この燃料極基板は板形状であり、その平面形状及び大きさ（面積等）等は特に限定されない。また、その厚さは、固体電解質層及び空気極層より厚く、固体電解質層の厚さの２０倍以上であることが好ましい。２０倍未満であると固体電解質層を支持するための機械的強度が十分でなくなる場合がある。更に、この厚さは２００〜３０００μｍ（より好ましくは５００〜２０００μｍ）であることが好ましい。２００μｍ未満であると基板としての機械的強度が充分でない場合があり、また、３０００μｍを超えて厚いと特にＳＯＦＣとなった時の発電効率（体積効率）が低下する場合がある。
【００１３】
上記「固体電解質層」は、電池の稼働時に燃料極側に供給される酸化剤ガス又は空気極側に供給される燃料ガスのうちの一方の一部をイオンとして移動できるイオン導電性を有する。どのようなイオンを導電できるかは特に限定されないが、例えば、酸素イオンや水素イオン等を挙げることができる。
また、固体電解質層を構成する固体電解質材料は特に限定されず、各種の固体電解質材料を用いることができ、使用条件等により適宜選択することが好ましい。このような固体電解質材料としてはＺｒＯ２系酸化物、ＬａＧａＯ３系酸化物、ＢａＣｅＯ３系酸化物、ＳｒＣｅＯ３系酸化物、ＳｒＺｒＯ３系酸化物及びＣａＺｒＯ３系酸化物等を挙げることができる。これらの固体電解質材料の中でも、ＺｒＯ２系酸化物が好ましく、更には、Ｙ、Ｓｃ及び希土類元素（Ｙ及びＳｃを除く）のうちの少なくとも１種により全部又は一部が安定化されたＺｒＯ２系酸化物（以下、単に「安定化ジルコニア」という）が好ましい。これらの安定化ジルコニアは高いイオン導電性と優れた機械的強度とをバランスよく合わせ有するためである。
【００１４】
固体電解質層は、燃料極基板よりも薄い膜状である。その平面形状及び大きさ（面積等）は特に限定されないが、発電性能に優れるため平面形状は燃料極基板に対応するものであり、大きさも燃料極基板と略同じとすることができる。更に、固体電解質層の厚さは５〜１００μｍ（より好ましくは５〜５０μｍ、特に好ましくは５〜３０μｍ）であることが好ましい。固体電解質層の電気抵抗は厚さに比例し、電気抵抗は燃料電池の発電性能に影響する。一般に固体電解質層は薄いほど電気抵抗が小さく、発電性能は大きい。しかし、燃料極基板に支持されるとしても、過度に薄いと自身の機械的強度が十分に得られず好ましくない。従って、機械的強度を十分に保ちつつ、より優れた発電性能を発揮するために上記範囲であることが好ましい。
【００１５】
また、固体電解質層（図２の１２）は、図２に示すように、外周部（図２の１２１）が他の部分よりも厚く形成された形状とすることができる。後述するＳＯＦＣ（例えば、図９参照）ではセパレータ（図９の２１）と固体電解質層（図９の１２）とをシール部（図９の２２）を介して接合する必要がある。このシール部（図９の２２）は、通常、未加熱のシール材をセパレータと固体電解質層との間に挟んだ後、加熱されることで気密性が発揮される。しかし、加熱の際に未加熱のシール材と固体電解質層とが反応し、反応層が形成され易い。特に、加熱温度等の条件によっては固体電解質層を貫通するように反応層が形成される場合があるが、このような貫通した反応層はクラックの起点となり易い。このため、固体電解質層を貫通する反応層が形成されないように、未加熱のシール材と接する部分を厚く形成することにより、反応層が固体電解質層を貫通するように形成されることを効果的に防止できる。
尚、図２における固体電解質層１２と図９における固体電解質層１２とは形状が異なるが、便宜上同じ符号を用いる。同様に、本明細書中の他の図でも形状等が異なる場合であっても便宜上同じ符号を用いる。
【００１６】
この固体電解質層の厚く形成された部分のうちの最も厚い部分は、燃料極基板と反応防止層とに挟まれた部分の固体電解質層の厚さの１．２〜１０倍（より好ましくは１．５〜５倍、更に好ましくは１．５〜３倍）の厚さであることが好ましい。１．２倍未満であると厚く形成する効果が十分に得られ難い。一方、１０倍以上に形成する必要は通常生じない。
【００１７】
上記「空気極層」は、酸素源となる酸化剤ガスに晒され、ＳＯＦＣにおける正電極として機能するものである。空気極層を構成する空気極層材料は特に限定されず、各種の空気極層材料を用いることができる。空気極層用材料としては、Ｐｔ、Ａｕ、Ａｇ、Ｐｄ、Ｉｒ、Ｒｕ及びＲｈ等の１種の金属又は２種以上を含む合金、Ｌａ、Ｓｒ、Ｃｅ、Ｃｏ及びＭｎ等の酸化物（Ｌａ２Ｏ３、ＳｒＯ、Ｃｅ２Ｏ３、Ｃｏ２Ｏ３、ＭｎＯ２及びＦｅＯ等）、Ｌａ、Ｓｒ、Ｃｅ、Ｃｏ及びＭｎ等を少なくとも含む複合酸化物（Ｌａ１−ｘＳｒｘＣｏＯ３系酸化物、Ｌａ１−ｘＳｒｘＦｅＯ３系酸化物、Ｌａ１−ｘＳｒｘＣｏ１−ｙＦｅｙＯ３系酸化物、Ｌａ１−ｘＳｒｘＭｎＯ３系酸化物、Ｐｒ１−ｘＢａｘＣｏＯ３系酸化物及びＳｍ１−ｘＳｒｘＣｏＯ３系酸化物等）等を挙げることができる。
【００１８】
これらの空気極材料のなかでも複合酸化物が好ましく、更にはＲｍ１−ｘＭａｘＣｏＯ３系酸化物（但し、Ｒｍは希土類元素であり、ＭａはＳｒ又はＢａである。）が好ましい。このＲｍ１−ｘＭａｘＣｏＯ３系酸化物は、Ｒｍ元素及びＭａ元素に加えて、更にその他の元素により置換されていてもよい。これらのＲｍ１−ｘＭａｘＣｏＯ３系酸化物の中でもＲｍ１−ｘＭａｘＣｏＯ3 ±δとして表され、０．２≦ｘ≦０．８、且つ、０≦δ＜１（δは酸素過剰量又は酸素欠損量を表す。）であることがより好ましく、ＲｍはＬａ、Ｐｒ及びＳｍの少なくともいずれかであることが特に好ましい。これら条件を満たすＲｍ１−ｘＭａｘＣｏＯ３系酸化物としては、例えば、Ｌａ０．６Ｓｒ０．４ＣｏＯ3 ±δ、Ｐｒ０．５Ｂａ０．５ＣｏＯ3 ±δ及びＳｍ０．５Ｓｒ０．５ＣｏＯ3 ±δ等が挙げられる。
【００１９】
また、この空気極層は燃料極基板よりも薄い膜状である。その平面形状は特に限定されない。また、その大きさも特に限定されず、例えば、反応防止層と同じ大きさであってもよく、反応防止層よりも小さくてもよく、反応防止層よりも大きくてもよい。しかし、反応防止層による固体電解質層と空気極層との反応を防止する効果を十分に得るため、空気極層の大きさは、反応防止層と同じか又はそれよりも小さいものであることが好ましい。また、空気極層の厚さは、燃料極基板より薄ければ特に限定されないが、１０〜１００μｍ（より好ましくは２０〜５０μｍ）であることが好ましい。１０μｍ未満であると電極としての機能を十分果たすことができない場合があり、また、１００μｍを超えて厚いと剥離し易くなる場合がある。
【００２０】
上記「反応防止層」は、固体電解質層と空気極層との間に形成された層であり、固体電解質層と空気極層との反応を防止する層である。この反応防止層は、ＣｅＯ２の一部のＣｅが希土類元素（Ｃｅ、Ｓｃ及びＹを除く）、Ｓｃ及びＹのうちの少なくとも１種により置換されたＣｅＯ２系酸化物からなる。このＣｅＯ２系酸化物は、希土類元素（Ｃｅ、Ｓｃ及びＹを除く）、Ｓｃ及びＹに加えて、更にこれら以外の他の元素により置換されていてもよい。これらのＣｅＯ２系酸化物のうち、希土類元素（Ｃｅ、Ｓｃ及びＹを除く）、Ｓｃ及びＹのうちの少なくとも１種のみにより置換された（希土類元素（Ｃｅ、Ｓｃ及びＹを除く）、Ｓｃ及びＹを除く他の元素による置換がない）材料は、化学式Ｃｅ１−ｘＬｎｘＯ２±δ（Ｌｎは希土類元素（Ｃｅ、Ｓｃ及びＹを除く）、Ｓｃ及びＹのうちの少なくとも１種の元素であり、δは酸素過剰量又は酸素欠損量である。）で表される。上記化学式におけるｘは、通常、０．０５≦ｘ≦０．３である。更に、上記化学式におけるＬｎ元素の中でもＳｍ及びＧｄが好ましい。これらの条件を満たすＣｅＯ２系酸化物としては、例えば、Ｃｅ０．８Ｓｍ０．２Ｏ２±δ、Ｃｅ０．８Ｇｄ０．２Ｏ２±δ等を挙げることができる。
【００２１】
また、上記の希土類元素（Ｃｅ、Ｓｃ及びＹを除く）、Ｓｃ及びＹを除く他の元素としては、Ｇａ、Ａｌ等を挙げることができる。これらの元素を含むＣｅＯ２系酸化物は、化学式Ｃｅ１−ｘ（Ｌｎ１−ｙＭｂｙ）ｘＯ２±δ（Ｌｎは希土類元素（Ｃｅ、Ｓｃ及びＹを除く）、Ｓｃ及びＹのうちの少なくとも１種の元素であり、Ｍｂは上記の各元素であり、δは酸素過剰量又は酸素欠損量である。）で表される。上記化学式におけるｘ及びｙは、通常、０．０５≦ｘ≦０．３、０．００５≦ｙ≦０．０５である。更に、上記化学式におけるＬｎ元素の中でもＳｍ及びＧｄが好ましい。これらの条件を満たすＣｅＯ２系酸化物としては、例えば、Ｃｅ０．８Ｓｍ０．１９Ｇａ０．０１０２±δ、Ｃｅ０．８Ｇｄ０．１９Ｇａ０．０１Ｏ２±δ等を挙げることができる。
【００２２】
この反応防止層は、燃料極基板よりも薄く、通常、固体電解質層及び空気極層よりも薄い膜状である。また、この反応防止層の平面形状は特に限定されないが、通常、四角形であり、特に長方形又は正方形等である。
また、この反応防止層の大きさは、固体電解質層の面積よりも小さいものである。この「面積が小さい」とは、固体電解質層の反応防止層側平面の面積（反応防止層と接する面の面積だけでなく反応防止層が形成される側の全面積）が、反応防止層の固体電解質層側平面の面積よりも大きいことをいう。即ち、固体電解質層の一部が反応防止層下に露出する状態である。反応防止層の面積は、固体電解質層の面積よりも小さければよく、その割合等は特に限定されないが、固体電解質層の面積の２５〜９０％（より好ましくは３０〜９０％、特に好ましくは４０〜９０％、とりわけ好ましくは５０〜９０％）であることが好ましい。この面積の割合が２５％未満であると、通常、この反応防止層上に、反応防止層と略同じ大きさは又は反応防止層よりも小さく形成される空気極層の面積が過度に小さくなるため発電効率（体積効率）が低下する傾向にあり好ましくない。一方、９０％を超えると反応防止層を介さずにセパレータに接合できる領域が小さくなり、接合強度が十分に得られ難くなる傾向にある。
【００２３】
更に、反応防止層の面積が固体電解質層の面積よりも小さいことで露出される固体電解質層の部位は特に限定されないが、通常、固体電解質層の外周部である。この外周部はその全周が露出されていてもよく、一部のみが露出されていてもよいが、全周が露出されていることが好ましい。全周が露出された単電池であることにより、ＳＯＦＣにおいては、全周に渡って固体電解質層とセパレータとを接合できるため確実な気密を達成できる。尚、一部のみが露出された形状とは、例えば、固体電解質層の平面形状が長方形又は正方形である場合には、その１辺側のみが露出された形状や、２辺側が露出された形状や、３辺側が露出された形状を挙げることができる。これらの中でもより露出辺が多いものが好ましい。露出辺が多い方がより確実に気密を達成できるからである。
【００２４】
また、反応防止層の厚さは、通常、固体電解質層及び空気極層よりも薄く、且つ、１〜２０μｍ（好ましくは１〜１５μｍ、より好ましくは２〜１０μｍ、特に好ましくは２〜８μｍ）である。１μｍ未満であると固体電解質層と空気極層との反応を十分に防止できない場合や、反応防止層の形成時に固体電解質層と反応防止層との反応による高抵抗層の形成を十分に防止できない場合がある。一方、２０μｍを超えると反応防止層をイオンが通過する時の抵抗が大きくなる傾向にある。
【００２５】
上記の反応防止層の平面形状、面積及び厚さは各々の好ましい態様の組合せとすることができる。例えば、固体電解質層の全周が露出され、固体電解質層の面積の２５〜９０％に形成され、且つ、厚さが１〜２０μｍであるものとすることができる。また、固体電解質層の外周部の一部が露出され、固体電解質層の面積の２５〜９０％に形成され、且つ、厚さが１〜２０μｍであるものとすることもできる。これらのうちでは前者が好ましい。
【００２６】
本発明の単電池には、前述の燃料極基板、固体電解質層、空気極層及び反応防止層以外にも他の層を備えることができる。他の層としては、燃料極基板と固体電解質層との反応を防止する他の反応防止層を設けることができる。その他、燃料極基板と固体電解質層との間に、燃料極基板を構成する材料とは粒子径、組成及び組織等のうちの少なくともいずれかが異なる補助燃料極層等を設けることができる。
【００２７】
［２］単電池の製造
本発明の単電池を得る方法は特に限定されず、どのような方法であってもよい。この製造方法としては、例えば、下記（１）及び（２）を挙げることができる。
即ち、製造方法（１）は、燃料極基板となる未焼成シート又は燃料極基板となる仮焼体と、固体電解質層となる未焼成固体電解質層とを備える未焼成積層体を形成し、次いで、この未焼成積層体を焼成した後、得られた積層体の固体電解質層上に反応防止層となる未焼成反応防止層を形成し、その後、この未焼成反応防止層が形成された積層体を焼成する工程を備える。但し、この製造方法では、通常、上記工程の後、得られた積層体に形成された反応防止層上に空気極層となる未焼成空気極層を積層し、その後、この未焼成空気極層が形成された積層体を焼成する工程を備える。
【００２８】
また、製造方法（２）は、燃料極基板となる未焼成シート又は燃料極基板となる仮焼体と、固体電解質層となる未焼成固体電解質層と、反応防止層となる未焼成反応防止層とをこの順に備える未焼成積層体を形成し、その後、この未焼成積層体を一体に焼成する工程を備える製造方法。但し、この製造方法では、通常、上記工程の後、得られた積層体の反応防止層上に空気極層となる未焼成空気極層を積層し、次いで、この未焼成空気極層が形成された積層体を焼成する工程を備える。
【００２９】
上記製造方法（１）は、燃料極基板と固体電解質層との積層体を先に製造し、次いで、反応防止層を形成する方法である。
未焼成反応防止層は、未焼成固体電解質層及び未焼成空気極層に比べて焼成収縮は小さい。特に燃料極基板と比べるとその差は大きい。これは、燃料極基板は、焼成後に多孔質であることを要するため未焼成燃料極基板には焼失粒子等が配合されることが多く、また、その体積も他部に比べて大きいため、焼成収縮が大きいからである。このため反応防止層と燃料極基板との焼成収縮率を合わせるのは困難である。従って、製造方法（１）によると最も大きく収縮する燃料極基板が焼結された後に反応防止層を形成するため、反応防止層にクラックや割れを生じることを効果的に防止できる。
【００３０】
上記製造方法（２）は、燃料極基板、固体電解質層及び反応防止層を一体に焼成する方法である。
従来のように反応防止層（図３の１３）が、固体電解質層（図３の１２）と同じ大きさ又はそれより大きく（図３参照）、又は、燃料極基板（図４の１１）と固体電解質層（図４の１２）との両方を包むように（図４参照）、形成されていては、製造方法（２）では、前記理由から焼成時に反応防止層が他部に巻き込まれるように収縮し、反りを生じたり、反応防止層の端部からクラックや割れを生じることがある。しかし、本発明の単電池では、固体電解質層よりも反応防止層が小さく形成されているため焼成収縮の影響をより受け難く、製造方法（２）を用いて製造することができる。特に反応防止層の端部にクラックや割れを生じる確率は極めて効果的に抑えられる。
【００３１】
更に、製造方法（２）では上記の焼成収縮差を有することで、緻密であることを要する反応防止層の緻密化を促進できる。即ち、反応防止層と燃料極基板とを同時に焼成することで、反応防止層は燃料極基板の焼成収縮に伴い、単独で収縮するよりも大きく収縮される。上記焼成収縮差は特に限定はされないが、反応防止層にクラック及び割れ等の不具合を生じず、且つ、効果的に緻密化できるために、未焼成燃料極基板の焼成収縮率を、未焼成反応防止層の焼成収縮率の１．０２〜１．２５倍（より好ましく１．０５〜１．１８倍）の範囲に調整することが好ましい。
尚、焼成収縮率（％）とは、焼成前の所定部位の長さをＸ０ｍｍとし、単独で焼成した後の所定部位の長さをＸ１ｍｍとした場合に、（Ｘ０−Ｘ１）／Ｘ０×１００により算出される値である。
【００３２】
上記製造方法（１）及び（２）における、上記「燃料極基板となる未焼成シート」、上記「未焼成固体電解質層」、上記「未焼成反応防止層」及び上記「未焼成空気極層」の各々は、前述の組成となるように、各々の原料粉末や原料有機金属化合物（液状物）、バインダ、可塑剤、分散剤及び溶剤等の必要な原材料を混合して得られるスラリー又はペーストを成形して得ることができる。
また、上記「燃料極基板となる仮焼体」とは、燃料極基板となる未焼成シートを仮焼して得ることができる。但し、仮焼とは後述する焼成における温度よりも１００℃以上低い温度で加熱することを意味する。
更に、上記「焼成」は、各々１２００〜１４５０℃（より好ましくは、１２５０〜１４００℃）で行うことが好ましい。１２００℃未満であると、燃料極基板、固体電解質層及び反応防止層は十分に緻密化されない場合がある。一方、１５５０℃を超えると、固体電解質層及び反応防止層の界面において反応が起こり、高抵抗の層を生じる場合があり好ましくない。
【００３３】
［３］固体電解質型燃料電池
前記本発明の単電池は、この単電池と、セパレータと、単電池とセパレータとを気密に接合するシール部とを備える単電池ユニットし、この単電池ユニットの１つのみでもＳＯＦＣとして使用することができる。しかし、通常、単電池ユニット１つのみでは発電力が小さいため、これらを複数積層して使用する。
即ち、本発明のＳＯＦＣは、本発明の単電池（図９の１−１）と、セパレータ（図９の２１）と、単電池とセパレータとを気密に接合するシール部（図９の２２）とを備える単電池ユニット（図９の１−１、２１及び２２からなる）が複数積層されて備えられ、且つ、セパレータ（図９の２１）がシール部（図９の２２）を介して固体電解質層（図９の１２）に接合されているものである（図９参照）。
【００３４】
上記「セパレータ」は、ＳＯＦＣ中において各単電池の燃料極基板側と空気極層側との雰囲気を遮断し、積層された各単電池同士が分離されるように配置する為の治具である。このセパレータを構成する材料は特に限定されず、種々のセパレータ用材料を用いることができる。このセパレータ用材料としては、耐熱金属及びセラミック等を挙げることができる。このうち、耐熱金属としては、耐熱性ステンレス、耐熱ニッケル基合金（インコネル系等）、耐熱クロム基合金（プランゼ合金等）などを挙げることができる。また、セラミックとしてはアルミナ、マグネシア及びスピネル並びにこれらのうちの２種以上を含む混合焼結体等を挙げることができる。その他、セパレータの形状、大きさ及び厚さ等は特に限定されず、従来より公知の種々の態様とすることができる。
【００３５】
上記「シール部」は、セパレータと固体電解質層とを接合し、この接合によりセパレータと固体電解質層との気密を保持するものである。このシール部を構成する材料は特に限定されず、種々のシール用材料を用いることができる。このシール用材料としては、ガラス質シール材及び金属質シール材を挙げることができる。ガラス質シール材としては、結晶化ガラス、ガラスセラミックス及びガラス等を挙げることができる。また、金属質シール材としては、ニッケル、金及び銀等を主成分とする各種のロウ材を挙げることができる。
【００３６】
本発明の単電池及びＳＯＦＣを用いて発電する場合、燃料極基板側には燃料ガスを供給し、空気極層側には酸化剤ガスを供給する。このうち、燃料ガスとしては、水素や、水素源となる炭化水素や、水素と炭化水素との混合ガスや、更には、必要に応じて所定温度の水中を通過させた加湿燃料ガスや、水蒸気を混合した水蒸気混合燃料ガス等を挙げることができる。また、この炭化水素は特に限定されず、例えば、メタノール等のアルコール化合物、天然ガス、ナフサ、石炭ガス化ガス等を用いることができる。更に、炭素数が１〜１０（好ましくは１〜７、特に好ましくは１〜４）の飽和炭化水素（例えば、メタン、エタン、プロパン、ブタン及びペンタン等）及び不飽和炭化水素（例えば、エチレン及びプロピレン等）を主成分とするものが好ましく、更には、このうち飽和炭化水素を主成分とするものが特に好ましい。これらの炭化水素は１種のみを用いてもよく、２種以上を併用してもよい。また、窒素及びアルゴン等の不活性ガスを５０体積％以下含有するものであってもよい。
一方、酸化剤ガスとしては、酸素や、一酸化炭素や、これらと他の気体との混合ガス等を挙げることができる。また、窒素及びアルゴン等の不活性ガスを５０体積％以下含有するものであってもよい。これらの酸化剤ガスの中でも安全であり、且つ安価であるため空気が好ましい。
【００３７】
【実施例】
以下に実施例を用いて本発明を詳細に説明する。
［１］単電池の製造
（１）実施例１の単電池
〔１〕 未焼成燃料極基板の製造
酸化ニッケル粉末６０質量部と、ＺｒＯ２にＹを８モル％固溶させた安定化ジルコニア粉末４０質量部とを混合し、更に、気孔形成用粉末として人造黒鉛粉３０質量部を加えて混合して混合粉末を得た。次いで、この混合粉末に、分散剤１質量部と有機溶媒（トルエン：メチルエチルケトンを２：３で混合）３５質量部とを加え、アルミナ製ポットミルを用いて２４時間混合した。その後、得られた混合物に、可塑剤（ジブチルフタレート）７質量部とバインダ（ポリビニルアルコール）１６質量部とを加えて、更に３時間混合して燃料極基板用スラリーを得た。このスラリーをドクターブレード法により成形後、乾燥させて厚さ２００μｍのグリーンシートを得た。次いで、このグリーンシート７枚を積層圧着した後切断し、縦３０ｍｍ、横３０ｍｍ、厚さ１３００μｍの未焼成燃料極基板を得た。
【００３８】
〔２〕 未焼成固体電解質層の形成
ＺｒＯ２にＹを８モル％固溶させた安定化ジルコニア粉末１００質量部と、バインダとしてポリビニルアルコール１３質量部及びブチルカルビトール３５質量部とを混合して固体電解質層用スラリーを得た。その後、上記〔１〕で得られた未焼成燃料極基板の一面全面に得られた固体電解質層用スラリーをスクリーン印刷して、縦３０ｍｍ、横３０ｍｍ、厚さ２５μｍの未焼成固体電解質層を形成した。
【００３９】
〔３〕 未焼成反応防止層の形成
酸化セリウム粉末と酸化サマリウム粉末とをＣｅとＳｍとのモル比が１：４となるように秤量し、溶媒（エタノール）を加えて混合して得られたスラリーを１４００℃で６時間保持した。その後、溶媒（エタノール）を加えて湿式粉砕し、平均粒径０．６μｍのＣｅＯ２系酸化物粉末（Ｃｅ０．８Ｓｍ０．２Ｏ１．９）を得た。このＣｅＯ２系酸化物粉末１００質量部と、バインダとしてポリビニルアルコール１３質量部及びブチルカルビトール３５質量部とを混合して、反応防止層用スラリーを得た。その後、上記〔２〕で形成した未焼成固体電解質層の中心部上に得られた反応防止層用スラリーをスクリーン印刷して、縦１５ｍｍ、横１５ｍｍ、厚さ６μｍの未焼成反応防止層を形成した。
〔４〕 １次焼成
上記〔１〕〜〔３〕までに得られた未焼成積層体を１３５０℃で１時間保持して１次焼成し、燃料極基板（図１の１１）、固体電解質層（図１の１２）及び反応防止層（図１の１３）が一体に形成された１次積層体を得た。
【００４０】
〔５〕 空気極層の形成
化学式Ｌａ０．６Ｓｒ０．４ＣｏＯ３で表される市販の粉末（平均粒径２μｍ）１００質量部と、バインダとしてポリビニルアルコール１３質量部及びブチルカルビトール３５質量部とを混合して、空気極層用スラリーを得た。その後、上記〔１〕〜〔４〕を経て得られた１次積層体の反応防止層の中心部上に得られた空気極層用スラリーをスクリーン印刷して、縦５ｍｍ、横５ｍｍ、厚さ３０μｍの未焼成空気極層を形成した。次いで、この未焼成空気極層が形成された１次積層体を１１００℃で１時間保持し、空気極層（図１の１４）が形成された実施例１の単電池（図１の１−１）を得た（図１参照）。
【００４１】
（２）実施例２の単電池
上記（１）〔１〕〜〔３〕を行い、未焼成燃料極基板、未焼成固体電解質層及び未焼成反応防止層を同じように形成した後、未焼成反応防止層が形成されていない未焼成固体電解質層の外周部上に上記（１）〔２〕で用いた固体電解質層用スラリーをスクリーン印刷して、未焼成固体電解質層の外周部のみを実施例１の固体電解質層（２５μｍ）よりも２５μｍ厚くした。その他は、上記実施例１の単電池と同様にして実施例２の単電池（図２の１−２）を得た（図２参照）。
【００４２】
（３）比較例１の単電池
上記（１）〔１〕と同様にして未焼成燃料極基板を得た。その後、この燃料極基板の一面の中心部に上記（１）〔２〕と同じ固体電解質層用スラリーをスクリーン印刷して、縦１５ｍｍ、横１５ｍｍ、厚さ２５μｍの未焼成固体電解質層を形成した。その後、未焼成燃料極基板上に未焼成固体電解質層が形成された積層体を１３５０℃で１時間保持して焼成した。その後、得られた１次積層体の固体電解質層が形成されている側の全面（固体電解質層の全面と固体電解質層が形成されていない燃料極基板の表面）に上記（１）〔３〕と同じ反応防止層用スラリーをスクリーン印刷し、縦３０ｍｍ、横３０ｍｍ、厚さ６μｍの未焼成反応防止層を形成した。その後、未焼成反応防止層が形成された１次積層体を１３００℃で１時間保持して反応防止層が形成された２次積層体を得た。次いで、上記（１）〔５〕と同じ工程を行い空気極層を形成し、比較例１の単電池（図３の１−３）を得た（図３参照）。
【００４３】
［２］評価用電池の製造
（１）実施例１の単電池を用いた評価用電池
耐熱ステンレス（ＳＵＳ４３０）からなり、直径が４５ｍｍであり、厚さが０．１ｍｍであり、且つ中心部に□１５ｍｍの正方形の貫通孔が形成された金属板をセパレータ（図５の２１）として用いた。このセパレータの貫通孔に空気極層（図５の１４）が対応するように、上記［１］（１）で得られた実験例１の単電池の反応防止層（図５の１３）が形成されていない固体電解質層（図５の１２）の外周部とセパレータとの間にシール部（図５の２２）となるシール材（結晶化ガラス；組成：４３％ＢａＯ−３３％ＳｉＯ２−１５％ＺｎＯ−６％Ａｌ２Ｏ３−２％ＺｒＯ２−１％ＣａＯ）を挟み、温度９００℃で２０分間加熱保持して、接合し気密化し、単電池ユニット（図５の２ー１）を得た（図５参照）。
【００４４】
その後、この単電池ユニット（図５の２ー１）の空気極層側及び燃料極基板側の各々側のセパレータの外周部と、二重アルミナ管外管（図８の３１１）の端部とをシール用ガラス（市販耐熱ガラス管の切断片リング）を用いて接合し気密化した。その後、空気極層側及び燃料極基板側の各々の側の二重アルミナ管内管（図８の３１２）の先端に予め巻き付けてある白金網（図８の３２）を、空気極層（図５の１４）及び燃料極基板（図５の１１）の各々に接触させて白金網に接続されたリード線（図８の３３）から電力を取り出せるようにして実施例１の単電池（図８の１−１）を備える評価用電池３（図８参照）を得た。
【００４５】
（２）実験例２の単電池を用いた評価用電池
上記［２］（１）と同様に、実施例２の単電池（図２の１−２）の反応防止層（図２の１３）が形成されていない固体電解質層（図２の１２）の固体電解質層の他部より厚く形成された外周部（図２の１２１）とセパレータ（図６の２１）とを結晶化ガラスを用いて接合し気密化して単電池ユニット（図６の２−２）を得た（図６参照）。その後、上記［２］（１）と同様にして二重アルミナ管を取り付けて実施例２の単電池を備える評価用電池を得た。
【００４６】
（３）比較例１の単電池を用いた評価用電池
上記［２］（１）と同様に、比較例１の単電池（図３の１−３）の外周部の反応防止層（図３の１３）の表面と、セパレータ（図７の２１）とを結晶化ガラスを用いて接合し気密化して単電池ユニット（図７の２−３）を得た（図７参照）。その後、上記［２］（１）と同様にして二重アルミナ管を取り付けて比較例１の単電池を備える評価用電池を得た。
【００４７】
［３］評価試験及び結果
（１）
上記［２］（１）〜（３）で得られた各評価用電池の単電池ユニット部分が電気炉内に配置されるように設置した。また、燃料極基板側に接合された二重アルミナ管の内管には室温（約２５℃）の水中を通過させた加湿水素ガスを供給し、空気極層側に接合された二重アルミナ管の内管には大気と同じ比率となるように酸素と窒素とを混合した酸化剤ガスを供給した。このように各ガスを供給し、電気炉内を８００℃に保ち発電を開始し、開回路電圧と最大出力密度とを測定し、その結果を表１に示した。
開回路電圧は、燃料極基板及び空気極層の各々に接触する白金網から接続されたリード線間の電流値が０（Ａ）である時に測定した電圧（Ｖ）である。
また、最大出力密度は、単電池から取り出した電流密度値（Ａ／ｃｍ２）と、この電流密度値にける単電池の電圧（Ｖ）とを乗じて算出される出力密度（Ｗ／ｃｍ２）の最大値である。
【００４８】
【表１】
（２）結果
表１の結果より、セパレータを反応防止層にシール材で接合した比較例１では、開回路電圧は０．８２Ｖであり、理論値（１．１０２Ｖ）の７４．４％に留まっている。また、最大出力密度は０．２２Ｗ／ｃｍ２であった。
これに対して、固体電解質層の外周部とセパレータとをシール材で接合した実施例１では、開回路電圧は１．１０Ｖであり、理論値に達しており、比較例１に対して３４％向上している。また、最大出力密度は０．６８Ｗ／ｃｍ２であり、比較例１に対して３．１倍となっている。更に、固体電解質層の厚みを増した外周部とセパレータとをシール材で接合した実施例２では、開回路電圧は１．１０Ｖであり、理論値に達しており、また、比較例１に対して３４％向上している。また、最大出力密度は０．６６Ｗ／ｃｍ２であり、比較例１に対して３．０倍となっている。
【００５０】
また、評価試験を終えた後に、評価用電池を電気炉から取り出し、単電池を観察したところ、実施例１及び実施例２の単電池では、シール部及びその周辺に異常は認められなかった。これに対して、比較例１では、燃料極基板側のシール部にクラックを生じていることが観察された。このため、比較例１ではシール部付近の気密が十分でなかったために上記の発電性能の低下を生じていると考えられる。
【図面の簡単な説明】
【図１】本発明の単電池の一例（実施例１）の模式的な断面図である。
【図２】本発明の単電池の他例（実施例２）の模式的な断面図である。
【図３】比較品の単電池の一例（比較例１）の模式的な断面図である。
【図４】比較品の単電池の他例の模式的な断面図である。
【図５】本発明の単電池ユニットの一例（実施例１）の模式的な断面図である。
【図６】本発明の単電池ユニットの他例（実施例２）の模式的な断面図である。
【図７】比較品の単電池ユニットの一例（比較例１）の模式的な断面図である。
【図８】実施例（実施例１）で用いた評価用電池の説明図である。
【図９】本発明の固体電解質型燃料電池の一例の模式的な断面図である。
【符号の説明】
１ー１、１−２、１−３、１−４；単電池、１１；燃料極基板、１２；固体電解質層、１２１；外周部、１３；反応防止層、１４；空気極層、２ー１、２−２、２−３；単電池ユニット、２１；セパレータ、２２；シール部、３；評価用電池、３１１；二重アルミナ管外管、３１２；二重アルミナ管内管、３２；白金網、３３；リード線、３４；シール用ガラス、４；固体電解質型燃料電池。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a unit cell for a solid oxide fuel cell and a fuel cell using the same. More specifically, the present invention relates to a solid oxide fuel cell unit cell having a support membrane structure using a fuel electrode as a substrate and having a reaction preventing layer between the solid electrolyte layer and the air electrode, and a fuel cell using the same.
[0002]
[Prior art]
The flat-plate type solid oxide fuel cell unit cell (hereinafter, also simply referred to as “unit cell”) is particularly excellent in volumetric efficiency among the power generation performance. , Simply referred to as “SOFC”). A unit cell generally has a structure in which at least three parts of a fuel electrode, a solid electrolyte layer, and an air electrode are laminated in this order, and a type called a self-supporting membrane type and a type called a support membrane type depending on the thickness of each layer. It is divided into. Among these, the self-supporting membrane type cell has a structure in which the solid electrolyte layer is thickened so as to be self-supporting, and other portions are laminated on the thick film surface. On the other hand, a supporting membrane type cell has a structure in which an air electrode or a fuel electrode is thickened so that it can stand on its own, and a solid electrolyte layer and the other electrode are laminated on the thick film surface (for example, Patent Document 1). reference.). In the three parts required by the above unit cell, the electric resistance of the solid electrolyte layer is much higher than in the other parts. Furthermore, in order to lower the electric resistance of the solid electrolyte layer, it is necessary to heat and hold at a high temperature. For this reason, the supporting membrane type single cell capable of reducing the thickness of the solid electrolyte layer has a great merit in terms of efficiency compared to the self-supporting membrane type single cell.
[0003]
In this supporting membrane type unit cell, LaMnO in which a part of the A site is substituted with Sr is formed in the air electrode.3Yttria-stabilized zirconia is frequently used for the system oxide and the solid electrolyte layer. However, LaMnO3The system oxide and yttria-stabilized zirconia are highly reactive, and there is a problem that a high-resistance reaction phase is generated at the interface between the air electrode and the solid electrolyte layer during production, and the output of the battery is lowered. On the other hand, a technique for solving the problem by forming a reaction prevention layer mainly composed of cerium oxide between the air electrode and the solid electrolyte layer is known (see, for example, Patent Document 2). ).
[0004]
[Patent Document 1]
JP 2000-260436 A
[Patent Document 2]
JP 2001-283877 A
[0005]
[Problems to be solved by the invention]
In the said
The present invention has been made in view of the above, and it is difficult to cause cracking or peeling of the reaction preventing layer, and in the case of a solid oxide fuel cell, the reliability at the seal portion between the separator and the single cell is high and excellent. A solid oxide fuel cell unit cell capable of exhibiting power generation performance is provided. Further, the present invention provides a solid oxide fuel cell that uses this unit cell and has high reliability and can exhibit superior battery performance.
[0006]
[Means for Solving the Problems]
The present inventors examined a unit cell or the like on which a reaction preventing layer was formed. As a result, a unit cell (see FIG. 3) having a reaction prevention layer (13 in FIG. 3) having the same or larger area as the solid electrolyte layer (12 in FIG. 3) or a fuel electrode layer (see FIG. 4). 11) and a single cell (see FIG. 4) in which the reaction prevention layer (13 in FIG. 4) is coated on the entire surface of the laminate of the solid electrolyte layer (12 in FIG. 4), the reaction prevention layer is exposed on the end face. Therefore, if the handling is not careful, cracks may occur from the corners of the reaction preventing layer, or cracks may occur.
In addition, it has been found that in SOFCs using these single cells, the power generation performance is significantly lower than the theoretical value, and the performance may not be fully exhibited.
Furthermore, when these unit cells are manufactured, the reaction prevention layer has a smaller shrinkage in firing than the other parts, and therefore, when the fuel electrode substrate and the solid electrolyte layer are simultaneously fired, warpage is likely to occur, and Cracks and cracks occur from the corners. For this reason, conventionally, after firing the fuel electrode substrate and the solid electrolyte layer, the reaction preventing layer is formed in a separate process, which requires labor.
Then, it has been found that all of these many problems can be solved extremely effectively by forming the reaction prevention layer smaller than the solid electrolyte layer, and the present invention has been completed.
[0007]
The present invention is as follows.
The unit cell of the present invention includes a fuel electrode substrate, a solid electrolyte layer formed on one surface side of the fuel electrode substrate, and an air electrode layer formed on the opposite side of the fuel electrode substrate of the solid electrolyte layer. And between the solid electrolyte layer and the air electrode layer,2Part of Ce is rare earth element(Excluding Ce, Sc and Y), CeO substituted with at least one of Sc and Y2A support membrane type solid oxide fuel cell unit cell comprising a reaction-preventing layer made of a system oxide, wherein the reaction-preventing layer has a smaller area than the solid electrolyte layer.
The area of the reaction preventing layer is 25 to 90% of the area of the solid electrolyte layer, and the area of the air electrode layer is the same as or smaller than the reaction preventing layer. Can be. Further, the solid electrolyte layer includes Y, Sc and rare earth elements.(Excluding Y and Sc)Zirconia stabilized by at least one of them. Further, an unsintered sheet serving as the fuel electrode substrate or a calcined body serving as the fuel electrode substrate, an unsintered solid electrolyte layer serving as the solid electrolyte layer, and an unsintered reaction preventing layer serving as the reaction preventing layer are provided. It can obtain through the process of forming the unfired laminated body provided in order, and baking this unfired laminated body integrally after that.
[0008]
The solid oxide fuel cell of the present invention includes a unit cell of the present invention, a separator provided on the air electrode layer side of the unit cell for solid oxide fuel cell, the unit cell for solid oxide fuel cell, A solid oxide fuel cell comprising a plurality of unit cell units each having a seal part that hermetically joins a separator, wherein the separator is a single unit for the solid oxide fuel cell via the seal part. It is joined to the solid electrolyte layer provided in the battery.
Moreover, the said seal part shall consist of at least one of a glassy sealing material and a metallic sealing material. Furthermore, the site | part joined with the said separator of the said solid electrolyte layer can be thickened compared with the other part of this solid electrolyte layer.
[0010]
【The invention's effect】
According to the present invention, airtight reliability in the vicinity of the seal portion in the SOFC is high, and excellent power generation performance can be obtained.
In addition, when the area of the reaction preventing layer is 25 to 90% of the area of the solid electrolyte layer and the area of the air electrode layer is the same as or smaller than the reaction preventing layer, it is particularly excellent. Airtight reliability in the vicinity of the seal portion and excellent power generation performance can be obtained.
Further, the solid electrolyte layer is composed of Y, Sc and rare earth elements.(Excluding Y and Sc)In the case of zirconia stabilized by at least one of them, particularly excellent power generation performance can be obtained.
In addition, in the case of a unit cell obtained by a predetermined manufacturing method, the reaction prevention layer has a higher density and can reliably prevent the reaction between the solid electrolyte layer and the air electrode layer.
According to the solid oxide fuel cell of the present invention, the airtight reliability in the vicinity of the seal portion is high, and excellent power generation performance can be obtained.
Further, when the seal portion is made of at least one of a glassy sealing material and a metal sealing material, the reliability in the seal portion can be made particularly excellent.
When the part of the solid electrolyte layer joined to the separator is thicker than the other part of the solid electrolyte layer, a reaction layer formed by the reaction between the solid electrolyte layer and the seal part is formed through the solid electrolyte layer. The airtight reliability at the seal portion is particularly high, and excellent power generation performance can be obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
[1] Single cell
The “fuel electrode substrate” is exposed to a fuel gas serving as a hydrogen source and functions as a negative electrode in the SOFC. Further, it supports at least a solid electrolyte layer (usually also supports an air electrode layer and a reaction preventing layer). The fuel electrode material constituting the fuel electrode substrate is not particularly limited, and various fuel electrode materials can be used. For example, one kind of metal such as Pt, Au, Ag, Pd, Ir, Ru, Rh, Ni and Fe or an alloy containing two or more kinds, these metals or alloys and ZrO2Oxides (including stabilized zirconia, partially stabilized zirconia, etc.), mixtures with ceramics such as ceria and manganese oxide (including cermets), and oxides of metals such as Ni and Fe among these metals ( NiO and Fe2O3Etc.) and ZrO2And oxides (including stabilized zirconia, partially stabilized zirconia, etc.), mixtures with ceramics such as ceria and manganese oxide, and the like. Among these anode materials, nickel oxide (reduced to nickel during operation) and ZrO2Mixtures with system oxides are preferred, and moreover, ZrO2It is preferable that the system oxide is zirconia that is stabilized in whole or in part by yttria and / or scandia. This is because they have a good balance of electrical performance and mechanical strength as a fuel electrode substrate.
[0012]
This fuel electrode substrate has a plate shape, and its planar shape and size (area, etc.) are not particularly limited. Moreover, it is preferable that the thickness is thicker than a solid electrolyte layer and an air electrode layer, and is 20 times or more of the thickness of the solid electrolyte layer. If it is less than 20 times, the mechanical strength for supporting the solid electrolyte layer may be insufficient. Further, this thickness is preferably 200 to 3000 μm (more preferably 500 to 2000 μm). If the thickness is less than 200 μm, the mechanical strength as a substrate may not be sufficient, and if it exceeds 3000 μm, the power generation efficiency (volume efficiency) may be lowered particularly when SOFC is formed.
[0013]
The “solid electrolyte layer” has ionic conductivity capable of moving as a part of one of the oxidant gas supplied to the fuel electrode side or the fuel gas supplied to the air electrode side during battery operation. Although what kind of ion can be conducted is not particularly limited, examples thereof include oxygen ions and hydrogen ions.
Moreover, the solid electrolyte material which comprises a solid electrolyte layer is not specifically limited, Various solid electrolyte materials can be used, It is preferable to select suitably according to use conditions etc. As such a solid electrolyte material, ZrO2Oxide, LaGaO3Oxide, BaCeO3Oxide, SrCeO3Oxide, SrZrO3Oxide and CaZrO3Examples thereof include system oxides. Among these solid electrolyte materials, ZrO2Based oxides, and further Y, Sc and rare earth elements(Excluding Y and Sc)ZrO stabilized in whole or in part by at least one of2A system oxide (hereinafter simply referred to as “stabilized zirconia”) is preferable. This is because these stabilized zirconia has a good balance between high ionic conductivity and excellent mechanical strength.
[0014]
The solid electrolyte layer is in the form of a film that is thinner than the fuel electrode substrate. The planar shape and size (area, etc.) are not particularly limited, but since the power generation performance is excellent, the planar shape corresponds to the fuel electrode substrate, and the size can be substantially the same as that of the fuel electrode substrate. Furthermore, the thickness of the solid electrolyte layer is preferably 5 to 100 μm (more preferably 5 to 50 μm, particularly preferably 5 to 30 μm). The electric resistance of the solid electrolyte layer is proportional to the thickness, and the electric resistance affects the power generation performance of the fuel cell. In general, the thinner the solid electrolyte layer, the lower the electric resistance and the higher the power generation performance. However, even if it is supported by the fuel electrode substrate, if it is too thin, the mechanical strength of itself cannot be sufficiently obtained, which is not preferable. Therefore, the above range is preferable in order to exhibit better power generation performance while maintaining sufficient mechanical strength.
[0015]
Further, as shown in FIG. 2, the solid electrolyte layer (12 in FIG. 2) can have a shape in which the outer peripheral portion (121 in FIG. 2) is formed thicker than the other portions. In an SOFC (see, for example, FIG. 9) described later, it is necessary to join a separator (21 in FIG. 9) and a solid electrolyte layer (12 in FIG. 9) via a seal portion (22 in FIG. 9). This seal portion (22 in FIG. 9) usually exhibits hermeticity by being heated after sandwiching an unheated seal material between the separator and the solid electrolyte layer. However, the unheated sealing material reacts with the solid electrolyte layer during heating, and a reaction layer is easily formed. In particular, depending on conditions such as heating temperature, a reaction layer may be formed so as to penetrate the solid electrolyte layer, but such a penetration reaction layer is likely to be a starting point of a crack. For this reason, it is effective to form the reaction layer so as to penetrate the solid electrolyte layer by forming a thick part in contact with the unheated sealing material so that the reaction layer penetrating the solid electrolyte layer is not formed. Can be prevented.
The
[0016]
The thickest portion of the thick portion of the solid electrolyte layer is 1.2 to 10 times the thickness of the solid electrolyte layer sandwiched between the fuel electrode substrate and the reaction prevention layer (more preferably 1). The thickness is preferably 5 to 5 times, more preferably 1.5 to 3 times. If it is less than 1.2 times, it is difficult to sufficiently obtain the effect of forming a thick film. On the other hand, it is not usually necessary to form it 10 times or more.
[0017]
The “air electrode layer” is exposed to an oxidant gas serving as an oxygen source, and functions as a positive electrode in the SOFC. The air electrode layer material constituting the air electrode layer is not particularly limited, and various air electrode layer materials can be used. Examples of the air electrode layer material include one kind of metal such as Pt, Au, Ag, Pd, Ir, Ru, and Rh, or an alloy containing two or more kinds, oxides such as La, Sr, Ce, Co, and Mn (La2O3, SrO, Ce2O3, Co2O3, MnO2And FeO, etc.), La, Sr, Ce, Co, Mn, etc.1-xSrxCoO3Oxide, La1-xSrxFeO3Oxide, La1-xSrxCo1-yFeyO3Oxide, La1-xSrxMnO3Series oxide, Pr1-xBaxCoO3Oxides and Sm1-xSrxCoO3And the like).
[0018]
Of these air electrode materials, composite oxides are preferred, and further Rm.1-xMaxCoO3System oxides (where Rm is a rare earth element and Ma is Sr or Ba) are preferred. This Rm1-xMaxCoO3The system oxide may be further substituted with other elements in addition to the Rm element and the Ma element. These Rm1-xMaxCoO3Rm among oxides1-xMaxCoOThree ± δIt is more preferable that 0.2 ≦ x ≦ 0.8 and 0 ≦ δ <1 (δ represents an oxygen excess amount or an oxygen deficiency amount), and Rm represents La, Pr, and Sm. Particularly preferred is at least one of them. Rm that satisfies these conditions1-xMaxCoO3Examples of the system oxide include La0.6Sr0.4CoOThree ± δ, Pr0.5Ba0.5CoOThree ± δAnd Sm0.5Sr0.5CoOThree ± δEtc.
[0019]
Further, the air electrode layer has a film shape thinner than that of the fuel electrode substrate. The planar shape is not particularly limited. Moreover, the magnitude | size is not specifically limited, For example, the same magnitude | size as a reaction prevention layer may be sufficient, may be smaller than a reaction prevention layer, and may be larger than a reaction prevention layer. However, in order to sufficiently obtain the effect of preventing the reaction between the solid electrolyte layer and the air electrode layer by the reaction preventing layer, the size of the air electrode layer may be the same as or smaller than that of the reaction preventing layer. preferable. The thickness of the air electrode layer is not particularly limited as long as it is thinner than the fuel electrode substrate, but is preferably 10 to 100 μm (more preferably 20 to 50 μm). If the thickness is less than 10 μm, the function as an electrode may not be sufficiently achieved, and if it exceeds 100 μm, it may be easily peeled off.
[0020]
The “reaction prevention layer” is a layer formed between the solid electrolyte layer and the air electrode layer, and is a layer that prevents a reaction between the solid electrolyte layer and the air electrode layer. This reaction preventing layer is made of CeO.2Part of Ce is rare earth element(Excluding Ce, Sc and Y), CeO substituted with at least one of Sc and Y2It consists of a system oxide. This CeO2Oxides are rare earth elements(Excluding Ce, Sc and Y)In addition to Sc and Y, they may be further substituted with other elements other than these. These CeO2Rare earth elements(Excluding Ce, Sc and Y), Sc and Y substituted by at least one kind (rare earth elements(Excluding Ce, Sc and Y), Without substitution by other elements except Sc and Y), the material has the chemical formula Ce1-xLnxO2 ± δ(Ln is a rare earth element.(Excluding Ce, Sc and Y), Sc and Y, and δ is oxygen excess or oxygen deficiency. ). In the above chemical formula, x is usually 0.05 ≦ x ≦ 0.3. Furthermore, Sm and Gd are preferable among the Ln elements in the above chemical formula. CeO that satisfies these conditions2As the system oxide, for example, Ce0.8Sm0.2O2 ± δ, Ce0.8Gd0.2O2 ± δEtc.
[0021]
In addition, the above rare earth elements(Excluding Ce, Sc and Y)Examples of other elements other than, Sc and Y include Ga and Al. CeO containing these elements2The system oxide has the chemical formula Ce1-x(Ln1-yMby)xO2 ± δ(Ln is a rare earth element.(Excluding Ce, Sc and Y), Sc and Y, Mb is each of the above elements, and δ is an oxygen excess or oxygen deficiency. ). In the above chemical formula, x and y are usually 0.05 ≦ x ≦ 0.3 and 0.005 ≦ y ≦ 0.05. Furthermore, Sm and Gd are preferable among the Ln elements in the above chemical formula. CeO that satisfies these conditions2As the system oxide, for example, Ce0.8Sm0.19Ga0.0102 ± δ, Ce0.8Gd0.19Ga0.01O2 ± δEtc.
[0022]
This reaction preventing layer is thinner than the fuel electrode substrate, and is usually in the form of a film thinner than the solid electrolyte layer and the air electrode layer. The planar shape of the reaction preventing layer is not particularly limited, but is usually a quadrangle, and particularly a rectangle or a square.
Further, the size of the reaction preventing layer is smaller than the area of the solid electrolyte layer. This “small area” means that the area of the solid electrolyte layer on the side of the reaction preventing layer (the total area on the side where the reaction preventing layer is formed as well as the area of the surface in contact with the reaction preventing layer) It means that it is larger than the area of the solid electrolyte layer side plane. That is, a part of the solid electrolyte layer is exposed under the reaction preventing layer. The area of the reaction preventing layer may be smaller than the area of the solid electrolyte layer, and the ratio thereof is not particularly limited, but is 25 to 90% (more preferably 30 to 90%, particularly preferably 40) of the area of the solid electrolyte layer. -90%, particularly preferably 50-90%). When the proportion of this area is less than 25%, the area of the air electrode layer formed on the reaction prevention layer is usually approximately the same size as the reaction prevention layer or smaller than the reaction prevention layer is excessively small. Therefore, the power generation efficiency (volumetric efficiency) tends to decrease, which is not preferable. On the other hand, if it exceeds 90%, the region that can be bonded to the separator without using the reaction preventing layer becomes small, and it tends to be difficult to obtain sufficient bonding strength.
[0023]
Further, the portion of the solid electrolyte layer exposed when the area of the reaction preventing layer is smaller than the area of the solid electrolyte layer is not particularly limited, but is usually the outer peripheral portion of the solid electrolyte layer. The entire circumference of this outer peripheral portion may be exposed or only a part thereof may be exposed, but it is preferable that the entire periphery is exposed. Since the entire cell is exposed in the unit cell, in the SOFC, since the solid electrolyte layer and the separator can be bonded over the entire periphery, reliable airtightness can be achieved. For example, when the planar shape of the solid electrolyte layer is a rectangle or a square, the shape in which only one side is exposed, or the shape in which two sides are exposed is used. Or, the shape in which the three sides are exposed can be mentioned. Among these, those having more exposed sides are preferable. This is because airtightness can be achieved more reliably with more exposed sides.
[0024]
The thickness of the reaction preventing layer is usually thinner than the solid electrolyte layer and the air electrode layer, and is 1 to 20 μm (preferably 1 to 15 μm, more preferably 2 to 10 μm, particularly preferably 2 to 8 μm). is there. If the thickness is less than 1 μm, the reaction between the solid electrolyte layer and the air electrode layer cannot be sufficiently prevented, or the formation of the high resistance layer due to the reaction between the solid electrolyte layer and the reaction prevention layer cannot be sufficiently prevented when forming the reaction prevention layer. There is a case. On the other hand, when the thickness exceeds 20 μm, the resistance when ions pass through the reaction preventing layer tends to increase.
[0025]
The planar shape, area, and thickness of the reaction preventing layer may be a combination of the preferable modes. For example, the entire circumference of the solid electrolyte layer is exposed, formed in 25 to 90% of the area of the solid electrolyte layer, and has a thickness of 1 to 20 μm. Moreover, a part of outer peripheral part of a solid electrolyte layer is exposed, it is formed in 25 to 90% of the area of a solid electrolyte layer, and thickness shall be 1-20 micrometers. Of these, the former is preferred.
[0026]
The unit cell of the present invention can include other layers in addition to the above-described fuel electrode substrate, solid electrolyte layer, air electrode layer, and reaction preventing layer. As the other layer, another reaction preventing layer for preventing the reaction between the fuel electrode substrate and the solid electrolyte layer can be provided. In addition, an auxiliary fuel electrode layer or the like having a particle diameter, a composition, a structure, or the like different from the material constituting the fuel electrode substrate can be provided between the fuel electrode substrate and the solid electrolyte layer.
[0027]
[2] Manufacture of single cells
The method for obtaining the unit cell of the present invention is not particularly limited, and any method may be used. As this manufacturing method, the following (1) and (2) can be mentioned, for example.
That is, the manufacturing method (1) forms an unfired laminate comprising an unfired sheet to be a fuel electrode substrate or a calcined body to be a fuel electrode substrate and an unfired solid electrolyte layer to be a solid electrolyte layer, After firing this unsintered laminate, an unsintered reaction prevention layer to be a reaction preventing layer is formed on the solid electrolyte layer of the obtained laminate, and then the unsintered reaction preventing layer is formed. The process of baking is provided. However, in this production method, usually, after the above-mentioned steps, a non-fired air electrode layer to be an air electrode layer is laminated on the reaction preventing layer formed in the obtained laminate, and then this non-fired air electrode layer A step of firing the laminated body on which is formed.
[0028]
In addition, the production method (2) includes an unsintered sheet serving as a fuel electrode substrate or a calcined body serving as a fuel electrode substrate, an unsintered solid electrolyte layer serving as a solid electrolyte layer, and an unsintered reaction preventing layer serving as a reaction preventing layer. And a manufacturing method including a step of firing the unfired laminated body integrally. However, in this production method, usually, after the above-mentioned steps, a non-fired air electrode layer to be an air electrode layer is laminated on the reaction preventing layer of the obtained laminate, and then this non-fired air electrode layer is formed. A step of firing the laminated body.
[0029]
The production method (1) is a method in which a laminate of a fuel electrode substrate and a solid electrolyte layer is produced first, and then a reaction preventing layer is formed.
The unsintered reaction preventing layer has smaller firing shrinkage than the unsintered solid electrolyte layer and unsintered air electrode layer. In particular, the difference is large compared to the fuel electrode substrate. This is because the fuel electrode substrate needs to be porous after firing, and the unfired fuel electrode substrate is often mixed with burned particles and the volume thereof is larger than other parts, This is because the shrinkage is large. For this reason, it is difficult to match the firing shrinkage rates of the reaction preventing layer and the fuel electrode substrate. Therefore, according to the manufacturing method (1), since the reaction preventing layer is formed after the fuel electrode substrate that contracts the most is sintered, it is possible to effectively prevent the reaction preventing layer from being cracked or cracked.
[0030]
The manufacturing method (2) is a method in which the fuel electrode substrate, the solid electrolyte layer, and the reaction preventing layer are integrally fired.
As in the prior art, the reaction preventing layer (13 in FIG. 3) is the same size as or larger than the solid electrolyte layer (12 in FIG. 3) (see FIG. 3), or the fuel electrode substrate (11 in FIG. 4) and In order to wrap both the solid electrolyte layer (12 in FIG. 4) (see FIG. 4), in the manufacturing method (2), the reaction preventing layer is entangled in other parts during firing for the above reasons. It may shrink and cause warping, or may crack or break from the end of the reaction preventing layer. However, in the unit cell of the present invention, since the reaction preventing layer is formed smaller than the solid electrolyte layer, it is less susceptible to firing shrinkage and can be manufactured using the manufacturing method (2). In particular, the probability of causing cracks or cracks at the end of the reaction preventing layer is extremely effectively suppressed.
[0031]
Furthermore, in the manufacturing method (2), by having the difference in firing shrinkage, it is possible to promote densification of the reaction preventing layer that needs to be dense. That is, by firing the reaction preventing layer and the fuel electrode substrate at the same time, the reaction preventing layer is contracted to a greater extent than the single contraction due to the firing contraction of the fuel electrode substrate. Although the firing shrinkage difference is not particularly limited, the firing shrinkage rate of the unfired fuel electrode substrate is set to the unfired reaction in order to prevent defects such as cracks and cracks in the reaction preventing layer and to effectively densify the layer. It is preferable to adjust to a range of 1.02 to 1.25 times (more preferably 1.05 to 1.18 times) the firing shrinkage rate of the prevention layer.
The firing shrinkage (%) is the length of a predetermined part before firing X0mm, and the length of the predetermined part after firing alone is X1mm, (X0-X1) / X0It is a value calculated by x100.
[0032]
In the production methods (1) and (2), the “unfired sheet to be a fuel electrode substrate”, the “unfired solid electrolyte layer”, the “unfired reaction prevention layer”, and the “unfired air electrode layer” Each of the above is a slurry or paste obtained by mixing necessary raw materials such as raw material powder, raw material organometallic compound (liquid material), binder, plasticizer, dispersant and solvent so as to have the above-mentioned composition. It can be obtained by molding.
The “calcined body to be a fuel electrode substrate” can be obtained by calcining an unfired sheet to be a fuel electrode substrate. However, calcination means heating at a temperature 100 ° C. or more lower than the temperature in firing described later.
Furthermore, it is preferable to perform the above “baking” at 1200 to 1450 ° C. (more preferably, 1250 to 1400 ° C.). When the temperature is lower than 1200 ° C., the fuel electrode substrate, the solid electrolyte layer, and the reaction preventing layer may not be sufficiently densified. On the other hand, when the temperature exceeds 1550 ° C., a reaction occurs at the interface between the solid electrolyte layer and the reaction preventing layer, which may cause a high resistance layer, which is not preferable.
[0033]
[3] Solid oxide fuel cell
The unit cell of the present invention is a unit cell unit including the unit cell, a separator, and a seal portion for airtightly bonding the unit cell and the separator, and only one of the unit cell units is used as an SOFC. Can do. However, since the power generation is usually small with only one single cell unit, a plurality of these are used by being stacked.
That is, the SOFC of the present invention includes the unit cell (1-1 in FIG. 9), the separator (21 in FIG. 9), and the seal portion (22 in FIG. 9) that airtightly joins the unit cell and the separator. A plurality of unit cell units (consisting of 1-1, 21 and 22 in FIG. 9) are stacked, and a separator (21 in FIG. 9) is solid through a seal portion (22 in FIG. 9). It is joined to the electrolyte layer (12 in FIG. 9) (see FIG. 9).
[0034]
The “separator” is a jig for arranging the unit cells to be separated from each other by blocking the atmosphere between the fuel electrode substrate side and the air electrode layer side of each unit cell in the SOFC. . The material constituting this separator is not particularly limited, and various separator materials can be used. Examples of the separator material include refractory metals and ceramics. Among these, examples of the heat-resistant metal include heat-resistant stainless steel, heat-resistant nickel-based alloys (such as Inconel), and heat-resistant chromium-based alloys (such as Planze alloys). Examples of the ceramic include alumina, magnesia, spinel, and a mixed sintered body containing two or more of these. In addition, the shape, size, thickness and the like of the separator are not particularly limited, and various conventionally known modes can be used.
[0035]
The “seal part” joins the separator and the solid electrolyte layer, and maintains airtightness between the separator and the solid electrolyte layer by this joining. The material which comprises this seal | sticker part is not specifically limited, A various sealing material can be used. Examples of the sealing material include a vitreous sealing material and a metallic sealing material. Examples of the glassy sealing material include crystallized glass, glass ceramics, and glass. Examples of the metallic sealing material include various brazing materials mainly composed of nickel, gold, silver, and the like.
[0036]
When power generation is performed using the unit cell and the SOFC of the present invention, fuel gas is supplied to the fuel electrode substrate side, and oxidant gas is supplied to the air electrode layer side. Among these, as the fuel gas, hydrogen, a hydrocarbon serving as a hydrogen source, a mixed gas of hydrogen and hydrocarbon, a humidified fuel gas that has been passed through water at a predetermined temperature as necessary, steam, A steam-mixed fuel gas in which is mixed. Moreover, this hydrocarbon is not specifically limited, For example, alcohol compounds, such as methanol, natural gas, naphtha, coal gasification gas, etc. can be used. Furthermore, saturated hydrocarbons (for example, methane, ethane, propane, butane, pentane, etc.) having 1 to 10 carbon atoms (preferably 1 to 7, particularly preferably 1 to 4) and unsaturated hydrocarbons (for example, ethylene and Those having propylene as the main component are preferred, and those having saturated hydrocarbons as the main component are particularly preferred. These hydrocarbons may use only 1 type and may use 2 or more types together. Moreover, you may contain 50 volume% or less of inert gas, such as nitrogen and argon.
On the other hand, examples of the oxidant gas include oxygen, carbon monoxide, and a mixed gas of these and other gases. Moreover, you may contain 50 volume% or less of inert gas, such as nitrogen and argon. Among these oxidant gases, air is preferable because it is safe and inexpensive.
[0037]
【Example】
Hereinafter, the present invention will be described in detail using examples.
[1] Manufacture of single cells
(1) Single cell of Example 1
[1] Production of unfired fuel electrode substrate
60 parts by mass of nickel oxide powder and ZrO240 parts by mass of stabilized zirconia powder in which 8 mol% of Y was solid-dissolved was mixed, and 30 parts by mass of artificial graphite powder was further added and mixed as a pore forming powder to obtain a mixed powder. Next, 1 part by mass of a dispersant and 35 parts by mass of an organic solvent (mixed with toluene: methyl ethyl ketone at 2: 3) were added to the mixed powder, and mixed for 24 hours using an alumina pot mill. Thereafter, 7 parts by mass of a plasticizer (dibutyl phthalate) and 16 parts by mass of a binder (polyvinyl alcohol) were added to the obtained mixture and further mixed for 3 hours to obtain a slurry for a fuel electrode substrate. The slurry was molded by the doctor blade method and then dried to obtain a green sheet having a thickness of 200 μm. Next, the seven green sheets were laminated and pressure-bonded and then cut to obtain an unfired fuel electrode substrate having a length of 30 mm, a width of 30 mm, and a thickness of 1300 μm.
[0038]
[2] Formation of unsintered solid electrolyte layer
ZrO2A solid electrolyte layer slurry was obtained by mixing 100 parts by mass of stabilized zirconia powder in which 8 mol% of Y was solid-solved with 13 parts by mass of polyvinyl alcohol and 35 parts by mass of butyl carbitol as a binder. Then above[1]The solid electrolyte layer slurry obtained on the whole surface of the unfired fuel electrode substrate obtained in the above was screen-printed to form an unfired solid electrolyte layer having a length of 30 mm, a width of 30 mm, and a thickness of 25 μm.
[0039]
[3] Formation of an unfired reaction prevention layer
The cerium oxide powder and the samarium oxide powder were weighed so that the molar ratio of Ce and Sm was 1: 4, and a slurry obtained by adding and mixing a solvent (ethanol) was held at 1400 ° C. for 6 hours. Then, a solvent (ethanol) was added and wet-pulverized, and CeO having an average particle size of 0.6 μm.2Oxide powder (Ce0.8Sm0.2O1.9) This CeO2100 parts by mass of the system oxide powder, 13 parts by mass of polyvinyl alcohol and 35 parts by mass of butyl carbitol as a binder were mixed to obtain a slurry for a reaction preventing layer. Then above[2]The slurry for the reaction preventing layer obtained on the central part of the unfired solid electrolyte layer formed in the above was screen-printed to form an unfired reaction preventing layer having a length of 15 mm, a width of 15 mm, and a thickness of 6 μm.
[4] Primary firing
the above[1]~[3]The unfired laminated body obtained up to this time is subjected to primary firing by holding at 1350 ° C. for 1 hour, and a fuel electrode substrate (11 in FIG. 1), a solid electrolyte layer (12 in FIG. 1), and a reaction preventing layer (in FIG. A primary laminate in which 13) was integrally formed was obtained.
[0040]
[5] Formation of the air electrode layer
Chemical formula La0.6Sr0.4CoO3And 100 parts by mass of a commercially available powder (
[0041]
(2) Single cell of Example 2
Above (1)[1]~[3]And forming the unfired fuel electrode substrate, the unfired solid electrolyte layer, and the unfired reaction preventing layer in the same manner, and then on the outer periphery of the unfired solid electrolyte layer where the unfired reaction preventing layer is not formed ( 1)[2]The slurry for the solid electrolyte layer used in the above was screen-printed, and only the outer periphery of the unfired solid electrolyte layer was made 25 μm thicker than the solid electrolyte layer (25 μm) of Example 1. Otherwise, the single cell of Example 2 (1-2 in FIG. 2) was obtained in the same manner as the single cell of Example 1 (see FIG. 2).
[0042]
(3) Cell of Comparative Example 1
Above (1)[1]In the same manner as above, an unfired fuel electrode substrate was obtained. Thereafter, (1) above in the center of one surface of the fuel electrode substrate.[2]The same solid electrolyte layer slurry was screen-printed to form an unfired solid electrolyte layer having a length of 15 mm, a width of 15 mm, and a thickness of 25 μm. Thereafter, the laminate in which the unfired solid electrolyte layer was formed on the unfired fuel electrode substrate was held at 1350 ° C. for 1 hour and fired. Then, the above (1) is applied to the entire surface of the obtained primary laminate on which the solid electrolyte layer is formed (the entire surface of the solid electrolyte layer and the surface of the fuel electrode substrate on which the solid electrolyte layer is not formed).[3]The same slurry for reaction prevention layer was screen-printed to form an unfired reaction prevention layer having a length of 30 mm, a width of 30 mm, and a thickness of 6 μm. Then, the primary laminated body in which the unbaking reaction prevention layer was formed was hold | maintained at 1300 degreeC for 1 hour, and the secondary laminated body in which the reaction prevention layer was formed was obtained. Next, the above (1)[5]The same process was performed to form an air electrode layer, and a unit cell (1-3 in FIG. 3) of Comparative Example 1 was obtained (see FIG. 3).
[0043]
[2] Manufacture of evaluation batteries
(1) Evaluation battery using unit cell of Example 1
A metal plate made of heat-resistant stainless steel (SUS430), having a diameter of 45 mm, a thickness of 0.1 mm, and a square through hole of 15 mm in the center is used as a separator (21 in FIG. 5). It was. The reaction prevention layer (13 in FIG. 5) of the unit cell of Experimental Example 1 obtained in the above [1] (1) is formed so that the air electrode layer (14 in FIG. 5) corresponds to the through hole of this separator. A sealing material (crystallized glass; composition: 43% BaO-33% SiO) which becomes a seal portion (22 in FIG. 5) between the outer peripheral portion of the solid electrolyte layer (12 in FIG. 5) and the separator2-15% ZnO-6% Al2O3-2% ZrO2−1% CaO), and heated and held at a temperature of 900 ° C. for 20 minutes to join and hermetically seal to obtain a single cell unit (2-1 in FIG. 5) (see FIG. 5).
[0044]
Thereafter, the outer peripheral portion of the separator on each of the air electrode layer side and the fuel electrode substrate side of the unit cell unit (2-1 in FIG. 5), and the end of the double alumina outer tube (311 in FIG. 8) Were joined and hermetically sealed using a glass for sealing (a cut piece ring of a commercially available heat-resistant glass tube). Thereafter, a platinum mesh (32 in FIG. 8) wound around the tip of the double alumina tube (312 in FIG. 8) on each of the air electrode layer side and the fuel electrode substrate side is placed on the air electrode layer (FIG. 5). 14) and the fuel electrode substrate (11 in FIG. 5) so that power can be taken out from the lead wire (33 in FIG. 8) connected to the platinum net (see FIG. 8). An evaluation battery 3 (see FIG. 8) having 1-1) was obtained.
[0045]
(2) Evaluation battery using unit cell of Experimental Example 2
Similarly to the above [2] (1), the solid electrolyte layer (12 in FIG. 2) in which the reaction preventing layer (13 in FIG. 2) of the single cell of Example 2 (1-2 in FIG. 2) is not formed. The outer peripheral part (121 in FIG. 2) formed thicker than the other part of the solid electrolyte layer and the separator (21 in FIG. 6) are joined and crystallized using crystallized glass, and the unit cell unit (2-2 in FIG. 6) is formed. (See FIG. 6). Thereafter, a double alumina tube was attached in the same manner as in the above [2] (1) to obtain a battery for evaluation comprising the single battery of Example 2.
[0046]
(3) Evaluation battery using the single battery of Comparative Example 1
Similarly to the above [2] (1), the surface of the reaction preventing layer (13 in FIG. 3) on the outer periphery of the unit cell (1-3 in FIG. 3) of Comparative Example 1, and the separator (21 in FIG. 7) Were joined and crystallized using crystallized glass to obtain a unit cell unit (2-3 in FIG. 7) (see FIG. 7). Thereafter, a double alumina tube was attached in the same manner as in the above [2] (1) to obtain a battery for evaluation including the single battery of Comparative Example 1.
[0047]
[3] Evaluation test and results
(1)
It installed so that the single cell unit part of each battery for evaluation obtained by said [2] (1)-(3) might be arrange | positioned in an electric furnace. Further, the double alumina tube joined to the air electrode layer side is supplied with humidified hydrogen gas that has been passed through water at room temperature (about 25 ° C.) to the inner tube of the double alumina tube joined to the fuel electrode substrate side. The inner tube was supplied with an oxidant gas in which oxygen and nitrogen were mixed so as to have the same ratio as the atmosphere. Each gas was supplied in this way, the electric furnace was kept at 800 ° C., and power generation was started. The open circuit voltage and the maximum power density were measured, and the results are shown in Table 1.
The open circuit voltage is a voltage (V) measured when a current value between lead wires connected from the platinum mesh contacting each of the fuel electrode substrate and the air electrode layer is 0 (A).
The maximum output density is the current density value (A / cm2) And the cell voltage (V) at this current density value to calculate the output density (W / cm2).
[0048]
[Table 1]
(2) Results
From the results shown in Table 1, in Comparative Example 1 in which the separator was joined to the reaction preventing layer with a sealing material, the open circuit voltage was 0.82 V, which remained at 74.4% of the theoretical value (1.102 V). The maximum power density is 0.22 W / cm2Met.
On the other hand, in Example 1 in which the outer peripheral portion of the solid electrolyte layer and the separator were joined with a sealing material, the open circuit voltage was 1.10 V, reaching the theoretical value, and 34% compared to Comparative Example 1. It has improved. The maximum power density is 0.68 W / cm2It is 3.1 times that of Comparative Example 1. Furthermore, in Example 2 in which the outer peripheral portion with the increased thickness of the solid electrolyte layer and the separator were joined with a sealing material, the open circuit voltage was 1.10 V, which reached a theoretical value. 34%. The maximum power density is 0.66 W / cm2It is 3.0 times that of Comparative Example 1.
[0050]
In addition, after the evaluation test was completed, the evaluation battery was taken out from the electric furnace and the single cells were observed. As a result, in the single cells of Example 1 and Example 2, no abnormality was found in the seal portion and the vicinity thereof. On the other hand, in Comparative Example 1, it was observed that cracks were generated in the seal portion on the fuel electrode substrate side. For this reason, in the comparative example 1, since the airtight vicinity of a seal part was not enough, it is thought that the said electric power generation performance falls.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an example (Example 1) of a unit cell of the present invention.
FIG. 2 is a schematic cross-sectional view of another example (Example 2) of the unit cell of the present invention.
FIG. 3 is a schematic cross-sectional view of an example of a comparative cell (Comparative Example 1).
FIG. 4 is a schematic cross-sectional view of another example of a comparative cell.
FIG. 5 is a schematic cross-sectional view of an example (Example 1) of the unit cell unit of the present invention.
FIG. 6 is a schematic cross-sectional view of another example (Example 2) of the unit cell unit of the present invention.
FIG. 7 is a schematic cross-sectional view of an example (Comparative Example 1) of a single cell unit as a comparative product.
FIG. 8 is an explanatory diagram of an evaluation battery used in an example (Example 1).
FIG. 9 is a schematic cross-sectional view of an example of a solid oxide fuel cell of the present invention.
[Explanation of symbols]
1-1, 1-2, 1-3, 1-4; unit cell, 11; fuel electrode substrate, 12; solid electrolyte layer, 121; outer periphery, 13; reaction prevention layer, 14; 1, 2, 2-3; single cell unit, 21; separator, 22; seal part, 3; battery for evaluation, 311; double alumina outer tube, 312; double alumina inner tube, 32; 33;
Claims (7)
上記反応防止層は、上記固体電解質層より面積が小さいことを特徴とする固体電解質型燃料電池用単電池。A fuel electrode substrate; a solid electrolyte layer formed on one side of the fuel electrode substrate; and an air electrode layer formed on the opposite side of the fuel electrode substrate of the solid electrolyte layer; and the solid electrolyte layer; between the air Kikyokuso, part of Ce of CeO 2 (except for Ce, Sc and Y) a rare earth element, consisting of CeO 2 type oxide which is substituted by at least one of Sc and Y reaction A support membrane type solid oxide fuel cell unit cell comprising a prevention layer,
The unit cell for a solid oxide fuel cell, wherein the reaction preventing layer has a smaller area than the solid electrolyte layer.
上記セパレータは、上記シール部を介して上記固体電解質型燃料電池用単電池が備える上記固体電解質層に接合されていることを特徴とする固体電解質型燃料電池。The solid oxide fuel cell unit cell according to any one of claims 1 to 4, a separator provided on the air electrode layer side of the solid electrolyte fuel cell unit cell, and the solid electrolyte A solid oxide fuel cell comprising a plurality of unit cell units each including a unit cell for a fuel cell and a seal portion for airtightly joining the separator,
The solid electrolyte fuel cell, wherein the separator is bonded to the solid electrolyte layer of the solid oxide fuel cell unit cell through the seal portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002279950A JP4015913B2 (en) | 2002-09-25 | 2002-09-25 | Single cell for solid oxide fuel cell and fuel cell using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002279950A JP4015913B2 (en) | 2002-09-25 | 2002-09-25 | Single cell for solid oxide fuel cell and fuel cell using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2004119161A JP2004119161A (en) | 2004-04-15 |
| JP4015913B2 true JP4015913B2 (en) | 2007-11-28 |
Family
ID=32274810
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2002279950A Expired - Lifetime JP4015913B2 (en) | 2002-09-25 | 2002-09-25 | Single cell for solid oxide fuel cell and fuel cell using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4015913B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101937918B1 (en) * | 2010-10-14 | 2019-01-14 | 재단법인 포항산업과학연구원 | A method of producing a air electrode for a solid oxide fuel cell, Fuel cell stack, and Fuel cell power generation system manufactured by the method |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4934949B2 (en) * | 2004-07-20 | 2012-05-23 | トヨタ自動車株式会社 | Fuel cell, hydrogen separation membrane module, and manufacturing method thereof |
| JP2006139960A (en) * | 2004-11-10 | 2006-06-01 | Dainippon Printing Co Ltd | Single compartment type solid oxide fuel cell |
| JP4855686B2 (en) * | 2005-01-13 | 2012-01-18 | 本田技研工業株式会社 | Fuel cell |
| JP4931361B2 (en) * | 2005-03-29 | 2012-05-16 | 京セラ株式会社 | Fuel cell and fuel cell |
| US20080032178A1 (en) * | 2006-08-02 | 2008-02-07 | Phong Diep | Solid oxide fuel cell device with an elongated seal geometry |
| CN101682069B (en) * | 2007-04-12 | 2013-11-20 | 康宁股份有限公司 | Sealing materials, devices utilizing such materials and a method of making such devices |
| JP2008287969A (en) * | 2007-05-16 | 2008-11-27 | Nippon Telegr & Teleph Corp <Ntt> | Flat plate solid oxide fuel cell |
| JP4990076B2 (en) * | 2007-09-13 | 2012-08-01 | 日立造船株式会社 | Zeolite separation membrane, method for producing the same, and bonding agent |
| WO2010040182A1 (en) * | 2008-10-09 | 2010-04-15 | Ceramic Fuel Cells Limited | A solid oxide fuel cell or solid oxide fuel cell sub-component and methods of preparing same |
| KR101177621B1 (en) * | 2010-06-25 | 2012-08-27 | 한국생산기술연구원 | Manufacturing method of SOFC unit cell |
| JP4988072B1 (en) * | 2011-03-03 | 2012-08-01 | 日本碍子株式会社 | Solid oxide fuel cell |
| JP4913260B1 (en) * | 2011-03-03 | 2012-04-11 | 日本碍子株式会社 | Solid oxide fuel cell |
| JP5055463B1 (en) * | 2011-07-21 | 2012-10-24 | 日本碍子株式会社 | Fuel cell |
| JP6199697B2 (en) * | 2013-10-29 | 2017-09-20 | 日本特殊陶業株式会社 | Fuel cell single cell with separator, fuel cell stack, and manufacturing method thereof |
| EP3979378B1 (en) | 2019-06-03 | 2023-10-18 | Kyocera Corporation | Cell, cell stack device, module, and module housing device |
| EP4135080A1 (en) * | 2020-04-09 | 2023-02-15 | Kyocera Corporation | Cell, module, and module accommodation device |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0541227A (en) * | 1991-08-05 | 1993-02-19 | Fuji Electric Co Ltd | Solid electrolyte type fuel cell |
| JPH0567473A (en) * | 1991-09-09 | 1993-03-19 | Mitsui Eng & Shipbuild Co Ltd | Solid electrolyte fuel cell |
| JP2780885B2 (en) * | 1991-12-12 | 1998-07-30 | ワイケイケイ株式会社 | Solid electrolyte fuel cell |
| JPH10177862A (en) * | 1996-12-18 | 1998-06-30 | Mitsubishi Heavy Ind Ltd | Manufacture of high temperature solid electrolyte fuel cell |
| DE59706104D1 (en) * | 1997-10-02 | 2002-02-28 | Siemens Ag | Sealing a high temperature fuel cell or a high temperature fuel cell stack |
| JP2000048831A (en) * | 1998-07-27 | 2000-02-18 | Tokyo Gas Co Ltd | Solid oxide fuel cell |
| JP2001283877A (en) * | 2000-04-03 | 2001-10-12 | Tokyo Gas Co Ltd | Single cell of solid oxide fuel cell and method of manufacturing the same |
| JP2001351647A (en) * | 2000-06-09 | 2001-12-21 | Tokyo Gas Co Ltd | Solid oxide fuel cell |
| JP2004039574A (en) * | 2002-07-05 | 2004-02-05 | Tokyo Gas Co Ltd | Sealing material for low-temperature operating solid oxide fuel cells |
-
2002
- 2002-09-25 JP JP2002279950A patent/JP4015913B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101937918B1 (en) * | 2010-10-14 | 2019-01-14 | 재단법인 포항산업과학연구원 | A method of producing a air electrode for a solid oxide fuel cell, Fuel cell stack, and Fuel cell power generation system manufactured by the method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2004119161A (en) | 2004-04-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4737946B2 (en) | Solid electrolyte fuel cell | |
| JP4015913B2 (en) | Single cell for solid oxide fuel cell and fuel cell using the same | |
| JP3996861B2 (en) | Fuel cell and fuel cell | |
| JP5171159B2 (en) | Fuel cell and fuel cell stack, and fuel cell | |
| JP2008519404A (en) | Electrochemical cell structure and its manufacturing method by controlled powder method | |
| JP4018378B2 (en) | Solid oxide fuel cell and manufacturing method thereof | |
| JPH06140048A (en) | Solid electrolyte type fuel cell | |
| JP2005327507A (en) | Solid electrolyte fuel cell and its manufacturing method | |
| JP2002175814A (en) | Manufacturing method of fuel electrode for solid electrolyte type fuel cell, the solid electrolyte type fuel cell and its manufacturing method | |
| JP4332639B2 (en) | Fuel cell and method for producing the same | |
| JP4559068B2 (en) | Method for producing solid oxide fuel cell | |
| JP2006202727A (en) | Solid electrolyte fuel cell | |
| JPWO2014122807A1 (en) | Solid oxide fuel cell and method for producing the same | |
| JPH05151981A (en) | Solid electrolyte fuel cell | |
| JP2006172989A (en) | Solid electrolyte fuel battery cell and solid electrolyte fuel battery using it and its manufacturing method | |
| JP4994287B2 (en) | Method for producing solid oxide fuel cell and firing jig used for the production | |
| JP2009009738A (en) | Solid electrolyte fuel cell and its manufacturing method | |
| JP6060224B1 (en) | Current collecting member and fuel cell | |
| JP4579527B2 (en) | Fuel cell, fuel cell and method for producing fuel cell | |
| JP2007134133A (en) | Solid electrolyte fuel cell | |
| KR102109730B1 (en) | Method for fabricating solid oxide fuel cell | |
| JP5030747B2 (en) | Method for producing solid oxide fuel cell and firing jig used in the method | |
| KR101276690B1 (en) | Solid oxide fuel cell having the improved electrodes and its preparation | |
| JP5597177B2 (en) | Air electrode material for solid oxide fuel cell and solid oxide fuel cell | |
| JP4557578B2 (en) | Fuel cell, cell stack and fuel cell |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20041110 |
|
| RD04 | Notification of resignation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7424 Effective date: 20050606 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20070223 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20070508 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070706 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20070821 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20070914 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100921 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4015913 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100921 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100921 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110921 Year of fee payment: 4 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110921 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120921 Year of fee payment: 5 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120921 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130921 Year of fee payment: 6 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313111 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| EXPY | Cancellation because of completion of term |