JP2021034192A - Fuel electrode for solid oxide fuel cell - Google Patents
Fuel electrode for solid oxide fuel cell Download PDFInfo
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
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- Inert Electrodes (AREA)
- Fuel Cell (AREA)
Abstract
Description
本発明は、起動停止時に生じる電解質の亀裂を防止することができる固体酸化物形燃料電池用燃料極に関する。 The present invention relates to a fuel electrode for a solid oxide fuel cell that can prevent cracks in the electrolyte that occur when starting and stopping.
燃料電池の一つに、固体電解質に固体酸化物を用いた固体酸化物形燃料電池（Solid Oxide Fuel Cell：ＳＯＦＣ）がある。固体酸化物形燃料電池セルは、起動停止時に、燃料極が酸化還元による寸法変化を起こし、電解質に亀裂を生じやすいという欠点があった。この現象は、停止時の燃料極側への空気流入が原因で、燃料極が酸化雰囲気に暴露されて金属ニッケルが酸化ニッケルになる過程に、体積膨張や生成した酸化ニッケルによる焼結収縮が生じることによる。 One of the fuel cells is a solid oxide fuel cell (SOFC) in which a solid oxide is used as a solid electrolyte. The solid oxide fuel cell has a drawback that the fuel electrode undergoes a dimensional change due to redox at the time of starting and stopping, and the electrolyte is liable to crack. This phenomenon is caused by the inflow of air to the fuel electrode side at the time of stop, and in the process where the fuel electrode is exposed to the oxidizing atmosphere and the metallic nickel becomes nickel oxide, volume expansion and sintering contraction due to the generated nickel oxide occur. It depends.
この問題に対して、支持体にＭｎ化合物やＣｏ化合物を添加する技術が提案されている（特開２００５−１９０７３７号公報及び特開２００６−３０２６４３号公報）。しかしＭｎ化合物やＣｏ化合物は焼成過程の揮発が多く、生産設備を汚染するため、安定した生産を維持することが困難である。またＹＳＺへの固溶により長期運転中にＹＳＺが分解し粉末化する可能性がある。
また、特開２００５−１６６４８４号公報は、体積膨張を気孔で吸収するだけでは導電率が著しく低下するため、造孔剤を添加して気孔率と細孔径を制御することを提案している。しかし特開２００５−１６６４８４号公報の図３にあるように導電率は４００Ｓ／ｃｍしかなく、気孔率と細孔径の制御で高い導電性と酸化還元による寸法変化を同時に満足させることはできない。
また、特開２００７−２５０３２５号公報は、導電性支持体の線膨張率を調整して最初の還元による寸法変化を収縮させることを提案している。この発明では、初期の亀裂を抑制することができるが、２回目以降の還元については問題を解決していない。
To solve this problem, techniques for adding Mn compounds and Co compounds to the support have been proposed (Japanese Patent Laid-Open Nos. 2005-190737 and 2006-302643). However, it is difficult to maintain stable production of Mn compounds and Co compounds because they volatilize in the firing process and contaminate the production equipment. Further, due to the solid solution in YSZ, YSZ may be decomposed and powdered during long-term operation.
Further, Japanese Patent Application Laid-Open No. 2005-166484 proposes to control the porosity and the pore diameter by adding a pore-forming agent because the conductivity is remarkably lowered only by absorbing the volume expansion through the pores. However, as shown in FIG. 3 of JP-A-2005-166484, the conductivity is only 400 S / cm, and high conductivity and dimensional change due to redox cannot be satisfied at the same time by controlling the porosity and the pore diameter.
Further, Japanese Patent Application Laid-Open No. 2007-250325 proposes to adjust the coefficient of linear expansion of the conductive support to contract the dimensional change due to the initial reduction. In the present invention, the initial crack can be suppressed, but the problem is not solved for the second and subsequent reductions.
本発明は、起動停止時に生じる電解質の亀裂等の問題を解決することを目的とする。 An object of the present invention is to solve problems such as cracks in an electrolyte that occur when starting and stopping.
起動停止時に生じる電解質の亀裂等の起動停止特性だけを追求するのであれば、燃料極側導電体（支持体）・導電層中のニッケルの比率を下げれば、金属ニッケルの酸化による寸法変化を抑制することができるが、この場合、固体酸化物形電気化学デバイスとしての他の特性が低下する。本発明者らは、性能の面から高いガス透過性と導電性を有し、さらには信頼性の面から電解質膜との熱膨張差が小さくなるようにニッケルの比率を下げずに起動停止特性を高めることを試みた。その結果、Ｎｉ網目構造に１０μｍ以上の酸化物（ＮｉＯを除く）が点在する燃料極において、酸化度が４％以下である固体酸化物形燃料電池用燃料極を見出し、金属ニッケルの酸化が抑制されて起動停止特性を飛躍的に高めることができた。すなわち、本発明は、Ｎｉ網目構造に１０μｍ以上の酸化物（ＮｉＯを除く）が点在し、酸化度が４％以下である固体酸化物形燃料電池用燃料極を提供する。 If only the start-stop characteristics such as electrolyte cracks that occur during start-stop are pursued, reducing the ratio of nickel in the fuel electrode side conductor (support) / conductive layer suppresses dimensional changes due to oxidation of metallic nickel. However, in this case, other properties as a solid oxide electrochemical device are reduced. The present inventors have high gas permeability and conductivity from the viewpoint of performance, and further, from the viewpoint of reliability, start-stop characteristics without lowering the ratio of nickel so as to reduce the difference in thermal expansion from the electrolyte membrane. Attempted to increase. As a result, in the fuel electrode in which oxides (excluding NiO) of 10 μm or more are scattered in the Ni network structure, a fuel electrode for a solid oxide fuel cell having an oxidation degree of 4% or less was found, and the metal nickel was oxidized. It was suppressed and the start / stop characteristics could be dramatically improved. That is, the present invention provides a fuel electrode for a solid oxide fuel cell in which oxides (excluding NiO) of 10 μm or more are scattered in a Ni network structure and the degree of oxidation is 4% or less.
本発明により、金属ニッケルの酸化を抑制して寸法変化を抑えた燃料極側導電体（支持体）・導電層を具備する、起動停止特性に優れた固体酸化物形電気化学デバイスを提供することができる。なお、固体酸化物形燃料電池セル（ＳＯＦＣ）及び固体酸化物形電解セル（ＳＯＥＣ）を総称して「固体酸化物形電気化学デバイス」という。 INDUSTRIAL APPLICABILITY According to the present invention, a solid oxide-type electrochemical device having excellent start-stop characteristics, provided with a fuel electrode side conductor (support) and a conductive layer that suppresses oxidation of metallic nickel and suppresses dimensional changes, is provided. Can be done. The solid oxide fuel cell (SOFC) and the solid oxide electrolytic cell (SOEC) are collectively referred to as a "solid oxide electrochemical device".
以下では、本明細書に開示する発明の実施の形態について図面を用いて詳細に説明する。以下の説明から、当業者にとって、本発明の多くの改良や他の実施の形態が明らかである。したがって、以下の説明は、例示としてのみ解釈されるべきであり、本発明を実行する最良の態様を当業者に教示する目的で提供されたものである。本発明の精神を逸脱することなく、その構造及び／又は機能の詳細を実質的に変更することができる。 Hereinafter, embodiments of the invention disclosed in the present specification will be described in detail with reference to the drawings. From the following description, many improvements and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the following description should be construed as an example only and is provided for the purpose of teaching those skilled in the art the best aspects of carrying out the present invention. The details of its structure and / or function can be substantially modified without departing from the spirit of the present invention.
［燃料極］
本発明の固体酸化物形燃料電池用燃料極は、Ｎｉ網目構造に１０μｍ以上の酸化物（ＮｉＯを除く）が点在するものである。Ｎｉ網目構造に１０μｍ以上の酸化物（ＮｉＯを除く）を点在させることで、ガス透過流束は１０ｍ3／ｍ2／Ｈｒ以上になり、発電性能を高めることができる。本発明の固体酸化物形燃料電池用燃料極は、好ましくはＮｉ網目構造に３０μｍ以上の酸化物（ＮｉＯを除く）が点在するものである。Ｎｉ網目構造に点在する酸化物（ＮｉＯを除く）は、例えば固体酸化物形燃料電池セルを切断し、樹脂埋めし、研磨した後、ＳＥＭ−ＥＤＸを用いて観察することができる。
また、本発明の固体酸化物形燃料電池用燃料極は、その酸化度が４％以下である。酸化度を４％以下とすることで、起動停止時のＮｉの酸化を抑制することができ、したがって燃料極の膨張を抑制することができる。ここで、酸化度とは、燃料極を強制的に酸化させる処理（例えば、大気中４００℃に３０分間暴露）の前後の重量を計測し、以下の計算式から求めることができる。
δ＝（ａ＋ｂ−ｂ・Ｘ）・（Ｇ２／Ｇ１−１）／ｂ／Ｘ
Ｘ：ＮｉＯ比率
Ｇ１：燃料極の初期重量（単位：ｇ）
Ｇ２：４００℃に３０分間暴露させたあとの重量（単位：ｇ）
ａ：Ｎｉのモル質量（ｇ／ｍｏｌ）
ｂ：Ｏのモル質量（ｇ／ｍｏｌ）
酸化度は、好ましくは３％以下である。
本発明の固体酸化物形燃料電池用燃料極は、好ましくは７００℃における導電率が１５００Ｓ／ｃｍ以上である。７００℃における導電率を１５００Ｓ／ｃｍ以上とすることで、発電性能を良好なものとすることができる。導電率は、より好ましくは２６００Ｓ／ｃｍ以上であり、さらに好ましくは３４００Ｓ／ｃｍ以上である。
本発明の固体酸化物形燃料電池用燃料極は、好ましくはガス透過流束が１０ｍ3／ｍ2／ｈｒ以上である。ガス透過流束を１０ｍ3／ｍ2／ｈｒ以上とすることで、発電性能を良好なものとすることができる。ガス透過流束は、より好ましくは２０ｍ3／ｍ2／ｈｒ以上であり、さらに好ましくは３０ｍ3／ｍ2／ｈｒ以上である。
[Fuel pole]
The fuel electrode for a solid oxide fuel cell of the present invention has an oxide of 10 μm or more (excluding NiO) scattered in a Ni network structure. By interspersing oxides (excluding NiO) of 10 μm or more in the Ni network structure, the gas permeation flux becomes 10 m 3 / m 2 / Hr or more, and the power generation performance can be improved. The fuel electrode for a solid oxide fuel cell of the present invention preferably has an oxide of 30 μm or more (excluding NiO) scattered in a Ni network structure. Oxides (excluding NiO) scattered in the Ni network structure can be observed using, for example, SEM-EDX after cutting a solid oxide fuel cell, embedding it in a resin, and polishing it.
Further, the fuel electrode for a solid oxide fuel cell of the present invention has an oxidation degree of 4% or less. By setting the degree of oxidation to 4% or less, the oxidation of Ni at the time of starting and stopping can be suppressed, and therefore the expansion of the fuel electrode can be suppressed. Here, the degree of oxidation can be calculated from the following formula by measuring the weight before and after the process of forcibly oxidizing the fuel electrode (for example, exposing it to 400 ° C. in the atmosphere for 30 minutes).
δ = (a + bb ・ X) ・ (G2 / G1-1) / b / X
X: NiO ratio
G1: Initial weight of fuel electrode (unit: g)
G2: Weight after exposure to 400 ° C for 30 minutes (unit: g)
a: Molar mass of Ni (g / mol)
b: Molar mass of O (g / mol)
The degree of oxidation is preferably 3% or less.
The fuel electrode for a solid oxide fuel cell of the present invention preferably has a conductivity of 1500 S / cm or more at 700 ° C. By setting the conductivity at 700 ° C. to 1500 S / cm or more, the power generation performance can be improved. The conductivity is more preferably 2600 S / cm or more, still more preferably 3400 S / cm or more.
The fuel electrode for a solid oxide fuel cell of the present invention preferably has a gas permeation flux of 10 m 3 / m 2 / hr or more. By setting the gas permeation flux to 10 m 3 / m 2 / hr or more, the power generation performance can be improved. The gas permeation flux is more preferably 20 m 3 / m 2 / hr or more, and even more preferably 30 m 3 / m 2 / hr or more.
本発明の固体酸化物形燃料電池用燃料極は、例えばＮｉＯと、酸化物（ＮｉＯを除く）とを含む原料であって、ＮｉＯ比率（ＮｉＯと酸化物（ＮｉＯを除く）との重量比率（ＮｉＯ／酸化物（ＮｉＯを除く）））が５０以上９８以下である原料を用いて作製される。前記ＮｉＯ比率は、好ましくは５０以上７５以下である。前記酸化物（ＮｉＯを除く）は、ＮｉＯと反応しにくく、かつ燃料電池システムを起動停止する際に懸念される酸化による化学変化と、それと同時に生じる体積変化が生じにくいことが望まれ、ジルコニウム含有酸化物、Ｙ2Ｏ3などが挙げられる。前記ジルコニウム含有酸化物は例えばＣａＯ、Ｙ2Ｏ3、Ｓｃ2Ｏ3のうちの１種以上をドープしたジルコニウム含有酸化物などが挙げられる。酸化物（ＮｉＯを除く）は、好ましくはＹＳＺ（イットリア安定化ジルコニア）である。この場合、固体酸化物形燃料電池用燃料極におけるＹＳＺ格子定数のひずみ率及びＮｉ格子定数のひずみ率は、それぞれ好ましくは０．０７％以内である。前記ひずみ率が０．０７％を超えると、燃料極中にマイクロクラックが発生しやすく、このマイクロクラックは再還元しても残存する。そして起動停止による酸化還元を繰り返すとマイクロクラック数は多くなる。マイクロクラックの生成は燃料極寸法の増大（＝膨張）を意味し、表面の電解質に引っ張り応力が働き、電解質亀裂を生じることになる。前記ひずみ率は、より好ましくは０．０４％以内である。
前記ジルコニウム含有酸化物の製造方法は、共沈法、アルコキシド加水分解法、ゾル−ゲル法、水熱沈殿法、水熱結晶化法、水熱分解法、水熱酸化法などが挙げられるが、得られるジルコニウム含有酸化物が、ＺｒＯ2結晶中にドープするＣａＯ、Ｙ2Ｏ3、Ｓｃ2Ｏ3が均一固溶した立方晶であればよい。
酸化物（ＮｉＯを除く）は、ＢＥＴ値が好ましくは３以上、より好ましくは５以上である。ＢＥＴ値が３未満の場合、燃料極の焼結開始温度が電解質焼結開始温度より高くなり、その結果、電解質膜に亀裂を生じやすくなる。また、酸化物（ＮｉＯを除く）は、粒度Ｄ１０が好ましくは１μｍ以上、より好ましくは４μｍ以上である。Ｄ１０が１μｍ未満の場合、ＮｉＯ原料同士の焼結を阻害しやすく、その結果、酸化度が高くなる。
The fuel electrode for a solid oxide fuel cell of the present invention is, for example, a raw material containing NiO and an oxide (excluding NiO), and has a NiO ratio (a weight ratio of NiO and an oxide (excluding NiO) (excluding NiO). NiO / oxide (excluding NiO))) is produced using a raw material having a content of 50 or more and 98 or less. The NiO ratio is preferably 50 or more and 75 or less. It is desired that the oxides (excluding NiO) do not easily react with NiO, and that chemical changes due to oxidation, which are a concern when starting and stopping the fuel cell system, and volume changes that occur at the same time are unlikely to occur, and contain zirconium. Oxides, Y 2 O 3 and the like can be mentioned. Examples of the zirconium-containing oxide include zirconium-containing oxides doped with one or more of CaO, Y 2 O 3 , and Sc 2 O 3. The oxide (excluding NiO) is preferably YSZ (yttria-stabilized zirconia). In this case, the strain rate of the YSZ lattice constant and the strain rate of the Ni lattice constant in the fuel electrode for the solid oxide fuel cell are preferably within 0.07%, respectively. If the strain rate exceeds 0.07%, microcracks are likely to occur in the fuel electrode, and these microcracks remain even after re-reduction. The number of microcracks increases when redox is repeated by starting and stopping. The formation of microcracks means an increase (= expansion) in the fuel electrode size, and tensile stress acts on the electrolyte on the surface, resulting in electrolyte cracks. The strain rate is more preferably within 0.04%.
Examples of the method for producing the zirconium-containing oxide include a coprecipitation method, an alkoxide hydrolysis method, a sol-gel method, a hydrothermal precipitation method, a hydrothermal crystallization method, a hydrothermal decomposition method, and a hydrothermal oxidation method. zirconium-containing oxide obtained is, CaO doped into ZrO 2 crystal, Y 2 O 3, Sc 2 O 3 is as long cubic were uniformly dissolved.
The oxide (excluding NiO) has a BET value of preferably 3 or more, more preferably 5 or more. When the BET value is less than 3, the sintering start temperature of the fuel electrode becomes higher than the electrolyte sintering start temperature, and as a result, cracks are likely to occur in the electrolyte membrane. The oxide (excluding NiO) has a particle size D10 of preferably 1 μm or more, more preferably 4 μm or more. When D10 is less than 1 μm, it is easy to inhibit the sintering of NiO raw materials, and as a result, the degree of oxidation becomes high.
［固体酸化物形燃料電池セル］
本発明の燃料極を用いた固体酸化物形電気化学デバイスの例として、固体酸化物形燃料電池セルについて以下で説明する。本発明の燃料極を用いた固体酸化物形燃料電池セルは、その形状は限定されず、例えば円筒状、板状、内部にガス流路を複数形成した中空板状などであってもよい。また複数の発電素子を直列に形成した横縞形セル（円筒横縞形セル、板状横縞形など）であってもよい。
また、発電素子は内側導電部（燃料極）、内側電極（燃料極触媒層）、固体電解質、外側電極（空気極触媒層）、外側導電部（空気極）が順次積層された積層体であるが、内側導電部に空気極、内側電極に空気極触媒層、外側電極に燃料極触媒層、外側導電部に燃料極であってもよい。
なお、起動停止や負荷追従など非安定運転中、スタックに温度分布由来の応力が発生しやすい。円筒型セルは非安定運転中にも破壊に至る応力が発生しにくく、起動停止を頻繁に行う場合や、負荷追従する場合は円筒型セルが望ましい。本発明の燃料極は起動停止時に生じるレドックス特性を改善するものである。円筒型セルの起動停止特性をさらに向上させることから、特に内側導電部が燃料極の円筒セルがより望ましい。
図１は本発明の燃料極を用いた固体酸化物形燃料電池セルの断面の一態様を示す模式図であり、内側電極を燃料極としたタイプについて示した。本発明における固体酸化物形燃料電池セル２１０は、例えば内側導電部（燃料極）２０１と、内側電極（燃料極触媒層）２０２、固体電解質２０３と、外側電極（空気極触媒層）２０４と、外側導電部（空気極）２０５から構成される。固体酸化物形燃料電池セルにおいて、各層の好ましい厚さは、内側導電部（燃料極）が０．５〜２ｍｍ、内側電極（燃料極触媒層）が１０〜２００μｍ、固体電解質が５〜６０μｍ、外側電極（空気極触媒層）が５〜５０μｍ、外側導電部（空気極）が１０〜２００μｍである。
[Solid oxide fuel cell]
As an example of the solid oxide fuel cell using the fuel electrode of the present invention, the solid oxide fuel cell will be described below. The shape of the solid oxide fuel cell using the fuel electrode of the present invention is not limited, and may be, for example, a cylindrical shape, a plate shape, or a hollow plate shape having a plurality of gas flow paths formed inside. Further, it may be a horizontal striped cell (cylindrical horizontal striped cell, plate-shaped horizontal striped cell, etc.) in which a plurality of power generation elements are formed in series.
The power generation element is a laminated body in which an inner conductive portion (fuel electrode), an inner electrode (fuel electrode catalyst layer), a solid electrolyte, an outer electrode (air electrode catalyst layer), and an outer conductive portion (air electrode) are sequentially laminated. However, the inner conductive portion may be an air electrode, the inner electrode may be an air electrode catalyst layer, the outer electrode may be a fuel electrode catalyst layer, and the outer conductive portion may be a fuel electrode.
During unstable operation such as start / stop and load tracking, stress due to temperature distribution is likely to occur in the stack. Cylindrical cells are less likely to generate stress that leads to failure even during unstable operation, and cylindrical cells are desirable when starting and stopping frequently or when following a load. The fuel electrode of the present invention improves the redox characteristics that occur when starting and stopping. A cylindrical cell having a fuel electrode on the inner conductive portion is particularly desirable because it further improves the start / stop characteristics of the cylindrical cell.
FIG. 1 is a schematic view showing an aspect of a cross section of a solid oxide fuel cell using the fuel electrode of the present invention, and shows a type in which the inner electrode is used as the fuel electrode. The solid oxide fuel cell 210 in the present invention includes, for example, an inner conductive portion (fuel electrode) 201, an inner electrode (fuel electrode catalyst layer) 202, a solid electrolyte 203, and an outer electrode (air electrode catalyst layer) 204. It is composed of an outer conductive portion (air electrode) 205. In the solid oxide fuel cell, the preferable thickness of each layer is 0.5 to 2 mm for the inner conductive portion (fuel electrode), 10 to 200 μm for the inner electrode (fuel electrode catalyst layer), and 5 to 60 μm for the solid electrolyte. The outer electrode (air electrode catalyst layer) is 5 to 50 μm, and the outer conductive portion (air electrode) is 10 to 200 μm.
図２は、本発明による燃料電池セルユニットを示す部分断面図である。図に示すように、燃料電池セルユニット１６は、燃料電池セル８４と、この燃料電池セル８４の上下方向端部にそれぞれ接続された内側電極端子８６とを備えてなる。燃料電池セル８４は、上下方向に延びる管状構造体であり、内部に燃料ガス流路８８を形成する円筒形の多孔質支持体９１上に内側電極層９０と、外側電極層９２と、内側電極層９０と外側電極層９２との間にある固体電解質９４とを備えてなる。
燃料電池セル８４の上端側と下端側に取り付けられた内側電極端子８６は、同一構造であるため、ここでは、上端側に取り付けられた内側電極端子８６について具体的に説明する。内側電極層９０の上部９０ａは、固体電解質９４と外側電極層９２に対して露出された外周面９０ｂと上端面９０ｃとを備える。内側電極端子８６は、導電性のシール材９６を介して内側電極層９０の外周面９０ｂと接続され、さらに、内側電極層９０の上端面９０ｃとは直接接触することにより、内側電極層９０と電気的に接続されている。内側電極端子８６の中心部には、内側電極層９０の燃料ガス流路８８と連通する燃料ガス流路９８が形成されている。
FIG. 2 is a partial cross-sectional view showing a fuel cell unit according to the present invention. As shown in the figure, the fuel cell unit 16 includes a fuel cell 84 and inner electrode terminals 86 connected to the vertical ends of the fuel cell 84, respectively. The fuel cell 84 is a tubular structure extending in the vertical direction, and has an inner electrode layer 90, an outer electrode layer 92, and an inner electrode on a cylindrical porous support 91 forming a fuel gas flow path 88 inside. It comprises a solid electrolyte 94 between the layer 90 and the outer electrode layer 92.
Since the inner electrode terminals 86 attached to the upper end side and the lower end side of the fuel cell 84 have the same structure, the inner electrode terminals 86 attached to the upper end side will be specifically described here. The upper 90a of the inner electrode layer 90 includes a solid electrolyte 94, an outer peripheral surface 90b exposed to the outer electrode layer 92, and an upper end surface 90c. The inner electrode terminal 86 is connected to the outer peripheral surface 90b of the inner electrode layer 90 via a conductive sealing material 96, and further comes into direct contact with the upper end surface 90c of the inner electrode layer 90 to contact the inner electrode layer 90. It is electrically connected. At the center of the inner electrode terminal 86, a fuel gas flow path 98 communicating with the fuel gas flow path 88 of the inner electrode layer 90 is formed.
［燃料極触媒層］
燃料極触媒層は、Ｎｉ／ＹＳＺ（イットリア安定化ジルコニア）などのＮｉＯ／ジルコニウム含有酸化物、Ｎｉ／ＧＤＣ（Ｇｄ2Ｏ3−ＣｅＯ2）などのＮｉＯ／セリウム含有酸化物などが挙げられる。ここで、ＮｉＯ／ジルコニウム含有酸化物とは、ＮｉＯとジルコニウム含有酸化物とが、所定の比率で均一に混合されたものを意味する。また、ＮｉＯ／セリウム含有酸化物とは、ＮｉＯとセリウム含有酸化物とが、所定の比率で均一に混合されたものを意味する。ＮｉＯ／ジルコニウム含有酸化物のジルコニウム含有酸化物としては、例えばＣａＯ、Ｙ2Ｏ3、Ｓｃ2Ｏ3のうちの１種以上をドープしたジルコニウム含有酸化物などが挙げられる。ＮｉＯ／セリウム含有酸化物のセリウム含有酸化物としては、一般式Ｃｅ1-yＬｎyＯ2（但し、ＬｎはＬａ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ、Ｓｃ、Ｙのいずれか１種又は２種以上の組み合わせであり、０．０５≦ｙ≦０．５０）などが挙げられる。なお、ＮｉＯは燃料雰囲気下で還元されてＮｉとなるため、前記混合物はそれぞれＮｉ／ジルコニウム含有酸化物又はＮｉ／セリウム含有酸化物となる。
[Fuel electrode catalyst layer]
Examples of the fuel electrode catalyst layer include NiO / zirconium-containing oxides such as Ni / YSZ (yttria-stabilized zirconia) and NiO / cerium-containing oxides such as Ni / GDC (Gd 2 O 3- CeO 2). Here, the NiO / zirconium-containing oxide means a mixture of NiO and a zirconium-containing oxide uniformly in a predetermined ratio. Further, the NiO / cerium-containing oxide means a mixture of NiO and cerium-containing oxide uniformly in a predetermined ratio. Examples of the zirconium-containing oxide of the NiO / zirconium-containing oxide include a zirconium-containing oxide doped with one or more of CaO, Y 2 O 3 , and Sc 2 O 3. The cerium-containing oxide of NiO / cerium-containing oxide represented by the general formula Ce 1-y Ln y O 2 ( where, Ln is La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm , Yb, Lu, Sc, Y, any one or a combination of two or more, and 0.05 ≦ y ≦ 0.50) and the like. Since NiO is reduced to Ni in a fuel atmosphere, the mixture becomes a Ni / zirconium-containing oxide or a Ni / cerium-containing oxide, respectively.
［空気極］
空気極としては、Ｌａ1-xＳｒxＣｏＯ3（但し、ｘ＝０．１〜０．３）及びＬａＣｏ1-xＮｉxＯ3（但し、ｘ＝０．１〜０．６）などのランタンコバルト系酸化物、（Ｌａ、Ｓｒ）ＦｅＯ3系と（Ｌａ、Ｓｒ）ＣｏＯ3系の固溶体であるランタンフェライト酸化物（ＬＳＣＦ：Ｌａ1-mＳｒmＣｏ1-nＦｅnＯ3（但し、０．０５＜ｍ＜０．５０、０＜ｎ＜１））などが挙げられる。
空気極は、例えば固体電解質側に配置する電極にＬａ0.6Ｓｒ0.4Ｃｏ0.2Ｆｅ0.8Ｏ3（＝空気極触媒層）を用い、導電部にＬａ0.6Ｓｒ0.4Ｃｏ0.8Ｆｅ0.2Ｏ3（＝空気極）を用いる。
[Air pole]
Examples of the air electrode include La 1-x Sr x CoO 3 (where x = 0.1 to 0.3) and La Co 1-x Ni x O 3 (where x = 0.1 to 0.6). lanthanum cobalt oxide, (La, Sr) FeO 3 system and (La, Sr) lanthanum ferrite oxide is CoO 3 based solid solution of (LSCF: La 1-m Sr m Co 1-n Fe n O 3 ( where , 0.05 <m <0.50, 0 <n <1)) and the like.
For the air electrode, for example, La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (= air electrode catalyst layer) is used for the electrode arranged on the solid electrolyte side, and La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3 (= air electrode) is used for the conductive part. ) Is used.
［固体電解質］
固体電解質としては、ランタンガレート系酸化物、固溶種としてＹ、Ｃａ、Ｓｃのいずれか１種又は２種以上を固溶した安定化ジルコニアなどが挙げられる。固体電解質は、好適にはＳｒ及びＭｇがドープされたランタンガレート系酸化物であり、より好適には一般式Ｌａ1-aＳｒaＧａ1-b-cＭｇbＣｏcＯ3（但し、０．０５≦ａ≦０．３、０＜ｂ＜０．３、０≦ｃ≦０．１５）で表されるランタンガレート系酸化物（ＬＳＧＭ）である。ここで、燃料極側には、反応抑制層として、Ｌａを固溶させたセリア（Ｃｅ1-xＬａxＯ2（但し、０．３＜ｘ＜０．５））を設けてもよい。反応抑制層は、好適にはＣｅ0.6Ｌａ0.4Ｏ2である。固体電解質は、単層であっても、又は複層であっても良い。固体電解質が複層である場合の例としては、例えば燃料極とＬＳＧＭからなる電解質層の間にＣｅ0.6Ｌａ0.4Ｏ2などの反応抑制層を用いる。
[Solid electrolyte]
Examples of the solid electrolyte include lanthanum gallate-based oxides, and stabilized zirconia in which any one or more of Y, Ca, and Sc are solid-solved as solid-dissolved species. The solid electrolyte is preferably a lanthanum gallate-based oxide Sr and Mg-doped, more preferably the general formula La 1-a Sr a Ga 1 -bc Mg b Co c O 3 ( where 0.05 It is a lanthanum gallate-based oxide (LSGM) represented by ≦ a ≦ 0.3, 0 <b <0.3, 0 ≦ c ≦ 0.15). Here, ceria (Ce 1-x La x O 2 (however, 0.3 <x <0.5)) in which La is solid-solved may be provided on the fuel electrode side as a reaction suppressing layer. The reaction suppression layer is preferably Ce 0.6 La 0.4 O 2 . The solid electrolyte may be a single layer or a multi-layer. As an example of the case where the solid electrolyte is a multi-layer, for example, a reaction suppression layer such as Ce 0.6 La 0.4 O 2 is used between the fuel electrode and the electrolyte layer composed of LSGM.
［燃料極導電部（支持体）の製造方法］
固体酸化物形燃料電池セルの製造方法は、特定のものに限定されるものではないが、燃料極導電部が支持体である場合について説明する。
ＮｉＯ及び酸化物（ＮｉＯを除く）を含有する原料粉体に、溶媒（水、アルコールなど）を添加して坏土を作製する。このとき、任意成分として、分散剤、バインダー、消泡剤、造孔剤等を添加してもよい。作製した坏土を成形し、乾燥して多孔質支持体を得る。坏土の成形には、シート成形法、プレス成形法、押出成形法などが用いられる
[Manufacturing method of fuel electrode conductive part (support)]
The method for manufacturing the solid oxide fuel cell is not limited to a specific one, but a case where the fuel electrode conductive portion is a support will be described.
A solvent (water, alcohol, etc.) is added to a raw material powder containing NiO and an oxide (excluding NiO) to prepare a clay. At this time, a dispersant, a binder, an antifoaming agent, a pore-forming agent, or the like may be added as optional components. The prepared clay is molded and dried to obtain a porous support. A sheet molding method, a press molding method, an extrusion molding method, etc. are used for molding the clay.
［成膜の製造方法］
内側電極、固体電解質、及び外側電極は、各原料粉末に、溶媒（水、アルコールなど）、分散剤、バインダー等の成形助剤を添加してスラリーを作製し、それをコーティングし、乾燥した後、焼成（１１００℃以上１４００℃未満）することによって得ることができる。コーティングは、複層の多孔質支持体の上層をコーティングする際に使用できる方法と同様に行うことができる。焼成は、各電極及び固体電解質の層を形成する都度行ってもよいが、複数の層を一度に焼成する「共焼成」を行うことが好ましい。また、電解質がドーパントの拡散等により変性しないように、焼成は酸化雰囲気下で行なうことが好ましい。より好適には、空気＋酸素の混合ガスを用い、酸素濃度は２０質量％以上３０質量％以下の雰囲気で焼成を行う。内側電極に燃料極を、外側電極に空気極を用いる場合、燃料極と電解質とを共焼成した後、空気極を成形し、共焼成よりも低い温度で焼成することが好ましい。
[Manufacturing method of film formation]
For the inner electrode, solid electrolyte, and outer electrode, a slurry is prepared by adding a molding aid such as a solvent (water, alcohol, etc.), a dispersant, a binder, etc. to each raw material powder, coated with the slurry, and dried. , Can be obtained by firing (1100 ° C. or higher and lower than 1400 ° C.). The coating can be performed in the same manner as the method that can be used to coat the upper layer of the multi-layer porous support. The firing may be performed each time each electrode and the layer of the solid electrolyte are formed, but it is preferable to perform "co-firing" in which a plurality of layers are fired at once. Further, the firing is preferably performed in an oxidizing atmosphere so that the electrolyte is not denatured due to diffusion of the dopant or the like. More preferably, a mixed gas of air + oxygen is used, and firing is performed in an atmosphere having an oxygen concentration of 20% by mass or more and 30% by mass or less. When a fuel electrode is used for the inner electrode and an air electrode is used for the outer electrode, it is preferable that the fuel electrode and the electrolyte are co-fired, then the air electrode is formed and fired at a temperature lower than that of co-firing.
［固体酸化物形燃料電池セルを用いた燃料電池システム］
固体酸化物形燃料電池セルを使用した固体酸化物形燃料電池システム１は、特定のものに限定されず、その製造や他の材料等は、公知のものが使用できる。図３は、本発明の一実施形態による固体酸化物形燃料電池システムを示す全体構成図である。この図３に示すように、固体酸化物形燃料電池システム１は、固体酸化物形燃料電池モジュール２と、補機ユニット４を備えている。
[Fuel cell system using solid oxide fuel cell]
The solid oxide fuel cell system 1 using the solid oxide fuel cell is not limited to a specific one, and known materials can be used for its production and other materials. FIG. 3 is an overall configuration diagram showing a solid oxide fuel cell system according to an embodiment of the present invention. As shown in FIG. 3, the solid oxide fuel cell system 1 includes a solid oxide fuel cell module 2 and an auxiliary machine unit 4.
固体酸化物形燃料電池モジュール２は、ハウジング６を備え、このハウジング６内部には、断熱材７を介して密封空間８が形成されている。なお、断熱材は設けないようにしても良い。この密封空間８の下方部分である発電室１０には、燃料ガスと酸化剤（空気）とにより発電反応を行う固体酸化物形燃料電池セル集合体１２が配置されている。この固体酸化物形燃料電池セル集合体１２は、１０個の固体酸化物形燃料電池セルスタック１４（図５参照）を備え、この固体酸化物形燃料電池セルスタック１４は、１６本の固体酸化物形燃料電池セルユニット１６（図２参照）から構成されている。このように、固体酸化物形燃料電池セル集合体１２は、１６０本の固体酸化物形燃料電池セルユニット１６を有し、これらの固体酸化物形燃料電池セルユニット１６の全てが直列接続されている。 The solid oxide fuel cell module 2 includes a housing 6, and a sealing space 8 is formed inside the housing 6 via a heat insulating material 7. The heat insulating material may not be provided. A solid oxide fuel cell assembly 12 that performs a power generation reaction with a fuel gas and an oxidant (air) is arranged in a power generation chamber 10 which is a lower portion of the sealed space 8. The solid oxide fuel cell assembly 12 includes 10 solid oxide fuel cell stacks 14 (see FIG. 5), and the solid oxide fuel cell stack 14 has 16 solid oxide fuel cell stacks. It is composed of a physical fuel cell unit 16 (see FIG. 2). As described above, the solid oxide fuel cell assembly 12 has 160 solid oxide fuel cell cell units 16, and all of these solid oxide fuel cell cell units 16 are connected in series. There is.
固体酸化物形燃料電池モジュール２の密封空間８の上述した発電室１０の上方には、燃焼室１８が形成され、この燃焼室１８で、発電反応に使用されなかった残余の燃料ガスと残余の酸化剤（空気）とが燃焼し、排気ガスを生成するようになっている。また、この燃焼室１８の上方には、燃料ガスを改質する改質器２０が配置され、前記残余ガスの燃焼熱によって改質器２０を改質反応が可能な温度となるように加熱している。さらに、この改質器２０の上方には、改質器２０の熱を受けて空気を加熱し、改質器２０の温度低下を抑制するための空気用熱交換器２２が配置されている。 A combustion chamber 18 is formed above the above-mentioned power generation chamber 10 in the sealed space 8 of the solid oxide fuel cell module 2. In this combustion chamber 18, residual fuel gas and residual fuel gas not used in the power generation reaction and residuals. The oxidizer (air) burns to generate exhaust gas. Further, a reformer 20 for reforming the fuel gas is arranged above the combustion chamber 18, and the reformer 20 is heated to a temperature at which the reforming reaction is possible by the combustion heat of the residual gas. ing. Further, above the reformer 20, an air heat exchanger 22 for receiving the heat of the reformer 20 to heat the air and suppressing the temperature drop of the reformer 20 is arranged.
次に、補機ユニット４は、水道等の水供給源２４からの水を貯水してフィルターにより純水とする純水タンク２６と、この純水タンクから供給される水の流量を調整する水流量調整ユニット２８を備えている。また、補機ユニット４は、都市ガス等の燃料供給源３０から供給された燃料ガスを遮断するガス遮断弁３２と、燃料ガスから硫黄を除去するための脱硫器３６と、燃料ガスの流量を調整する燃料流量調整ユニット３８を備えている。さらに、補機ユニット４は、空気供給源４０から供給される酸化剤である空気を遮断する電磁弁４２と、空気の流量を調整する改質用空気流量調整ユニット４４及び発電用空気流量調整ユニット４５と、改質器２０に供給される改質用空気を加熱する第１ヒータ４６と、発電室に供給される発電用空気を加熱する第２ヒータ４８とを備えている。これらの第１ヒータ４６と第２ヒータ４８は、起動時の昇温を効率よく行うために設けられているが、省略しても良い。 Next, the auxiliary machine unit 4 has a pure water tank 26 that stores water from a water supply source 24 such as tap water and turns it into pure water by a filter, and water that adjusts the flow rate of water supplied from the pure water tank. A flow rate adjusting unit 28 is provided. Further, the auxiliary machine unit 4 has a gas shutoff valve 32 that shuts off the fuel gas supplied from the fuel supply source 30 such as city gas, a desulfurizer 36 for removing sulfur from the fuel gas, and a flow rate of the fuel gas. A fuel flow rate adjusting unit 38 for adjusting is provided. Further, the auxiliary machine unit 4 includes an electromagnetic valve 42 that shuts off air, which is an oxidant supplied from the air supply source 40, a reforming air flow rate adjusting unit 44 that adjusts the air flow rate, and a power generation air flow rate adjusting unit. 45, a first heater 46 for heating the reforming air supplied to the reformer 20, and a second heater 48 for heating the power generation air supplied to the power generation chamber are provided. These first heater 46 and second heater 48 are provided in order to efficiently raise the temperature at the time of start-up, but may be omitted.
次に、固体酸化物形燃料電池モジュール２には、排気ガスが供給される温水製造装置５０が接続されている。この温水製造装置５０には、水供給源２４から水道水が供給され、この水道水が排気ガスの熱により温水となり、図示しない外部の給湯器の貯湯タンクへ供給されるようになっている。また、固体酸化物形燃料電池モジュール２には、燃料ガスの供給量等を制御するための制御ボックス５２が取り付けられている。さらに、固体酸化物形燃料電池モジュール２には、固体酸化物形燃料電池モジュールにより発電された電力を外部に供給するための電力取出部（電力変換部）であるインバータ５４が接続されている。 Next, the hot water production apparatus 50 to which the exhaust gas is supplied is connected to the solid oxide fuel cell module 2. Tap water is supplied to the hot water production apparatus 50 from the water supply source 24, and the tap water becomes hot water by the heat of the exhaust gas and is supplied to a hot water storage tank of an external water heater (not shown). Further, the solid oxide fuel cell module 2 is provided with a control box 52 for controlling the supply amount of fuel gas and the like. Further, the solid oxide fuel cell module 2 is connected to an inverter 54 which is a power extraction unit (power conversion unit) for supplying the electric power generated by the solid oxide fuel cell module to the outside.
次に、図４及び図６により、固体酸化物形燃料電池システムの固体酸化物形燃料電池モジュールの内部構造を説明する。図４は、固体酸化物形燃料電池システムの固体酸化物形燃料電池モジュールを示す側面断面図であり、図６は、図４のＩＩＩ−ＩＩＩ線に沿った断面図である。図４及び図６に示すように、固体酸化物形燃料電池モジュール２のハウジング６内の密封空間８には、上述したように、下方から順に、固体酸化物形燃料電池セル集合体１２、改質器２０、空気用熱交換器２２が配置されている。 Next, the internal structure of the solid oxide fuel cell module of the solid oxide fuel cell system will be described with reference to FIGS. 4 and 6. FIG. 4 is a side sectional view showing the solid oxide fuel cell module of the solid oxide fuel cell system, and FIG. 6 is a sectional view taken along the line III-III of FIG. As shown in FIGS. 4 and 6, in the sealed space 8 in the housing 6 of the solid oxide fuel cell module 2, as described above, the solid oxide fuel cell assembly 12 is modified in this order from the bottom. A pawn 20 and an air heat exchanger 22 are arranged.
改質器２０は、その上流端側に純水を導入するための純水導入管６０と改質される固体酸化物形燃料ガスと改質用空気を導入するための被改質ガス導入管６２が取り付けられ、また、改質器２０の内部には、上流側から順に、蒸発部２０ａと改質部２０ｂが形成され、改質部２０ｂには改質触媒が充填されている。この改質器２０に導入された水蒸気が混合された燃料ガス及び空気は、改質器２０内に充填された改質触媒により改質される。 The reformer 20 has a pure water introduction pipe 60 for introducing pure water and a solid oxide fuel gas reformed and a gas reformed gas introduction pipe for introducing reforming air on the upstream end side thereof. 62 is attached, and inside the reformer 20, an evaporation unit 20a and a reforming unit 20b are formed in this order from the upstream side, and the reforming unit 20b is filled with a reforming catalyst. The fuel gas and air mixed with water vapor introduced into the reformer 20 are reformed by the reforming catalyst filled in the reformer 20.
この改質器２０の下流端側には、燃料ガス供給管６４が接続され、この燃料ガス供給管６４は、下方に延び、さらに、固体酸化物形燃料電池セル集合体１２の下方に形成されたマニホールド６６内で水平に延びている。燃料ガス供給管６４の水平部６４ａの下方面には、複数の燃料供給孔６４ｂが形成されており、この燃料供給孔６４ｂから、改質された燃料ガスがマニホールド６６内に供給される。 A fuel gas supply pipe 64 is connected to the downstream end side of the reformer 20, and the fuel gas supply pipe 64 extends downward and is further formed below the solid oxide fuel cell assembly 12. It extends horizontally in the manifold 66. A plurality of fuel supply holes 64b are formed on the lower surface of the horizontal portion 64a of the fuel gas supply pipe 64, and the reformed fuel gas is supplied into the manifold 66 from the fuel supply holes 64b.
このマニホールド６６の上方には、上述した固体酸化物形燃料電池セルスタック１４を支持するための貫通孔を備えた下支持板６８が取り付けられており、マニホールド６６内の燃料ガスが、固体酸化物形燃料電池セルユニット１６内に供給される。 A lower support plate 68 having a through hole for supporting the solid oxide fuel cell stack 14 described above is attached above the manifold 66, and the fuel gas in the manifold 66 is a solid oxide fuel cell. It is supplied into the fuel cell unit 16.
次に、改質器２０の上方には、空気用熱交換器２２が設けられている。この空気用熱交換器２２は、上流側に空気集約室７０、下流側に２つの空気分配室７２を備え、これらの空気集約室７０と空気分配室７２は、６個の空気流路管７４により接続されている。ここで、図６に示すように、３個の空気流路管７４が一組（７４ａ，７４ｂ，７４ｃ，７４ｄ，７４ｅ，７４ｆ）となっており、空気集約室７０内の空気が各組の空気流路管７４からそれぞれの空気分配室７２へ流入する。 Next, an air heat exchanger 22 is provided above the reformer 20. The air heat exchanger 22 is provided with an air consolidating chamber 70 on the upstream side and two air distribution chambers 72 on the downstream side, and the air consolidating chamber 70 and the air distribution chamber 72 are composed of six air flow path pipes 74. Is connected by. Here, as shown in FIG. 6, the three air flow path pipes 74 form a set (74a, 74b, 74c, 74d, 74e, 74f), and the air in the air consolidating chamber 70 is a set of each set. It flows from the air flow path pipe 74 into each air distribution chamber 72.
空気用熱交換器２２の６個の空気流路管７４内を流れる空気は、燃焼室１８で燃焼して上昇する排気ガスにより予熱される。空気分配室７２のそれぞれには、空気導入管７６が接続され、この空気導入管７６は、下方に延び、その下端側が、発電室１０の下方空間に連通し、発電室１０に予熱された空気を導入する。 The air flowing through the six air flow path pipes 74 of the air heat exchanger 22 is preheated by the exhaust gas that burns in the combustion chamber 18 and rises. An air introduction pipe 76 is connected to each of the air distribution chambers 72, and the air introduction pipe 76 extends downward, and the lower end side thereof communicates with the space below the power generation chamber 10 to preheat the air to the power generation chamber 10. Introduce.
次に、マニホールド６６の下方には、排気ガス室７８が形成されている。また、図６に示すように、ハウジング６の長手方向に沿った面である前面６ａと後面６ｂの内側には、上下方向に延びる排気ガス通路８０が形成され、この排気ガス通路８０の上端側は、空気用熱交換器２２が配置された空間と連通し、下端側は、排気ガス室７８と連通している。また、排気ガス室７８の下面のほぼ中央には、排気ガス排出管８２が接続され、この排気ガス排出管８２の下流端は、図２に示す上述した温水製造装置５０に接続されている。図３に示すように、燃料ガスと空気との燃焼を開始するための点火装置８３が、燃焼室１８に設けられている。 Next, an exhaust gas chamber 78 is formed below the manifold 66. Further, as shown in FIG. 6, an exhaust gas passage 80 extending in the vertical direction is formed inside the front surface 6a and the rear surface 6b, which are surfaces along the longitudinal direction of the housing 6, and the upper end side of the exhaust gas passage 80 is formed. Communicates with the space where the air heat exchanger 22 is arranged, and the lower end side communicates with the exhaust gas chamber 78. An exhaust gas discharge pipe 82 is connected to substantially the center of the lower surface of the exhaust gas chamber 78, and the downstream end of the exhaust gas discharge pipe 82 is connected to the above-mentioned hot water production apparatus 50 shown in FIG. As shown in FIG. 3, an ignition device 83 for starting combustion of fuel gas and air is provided in the combustion chamber 18.
次に図５により固体酸化物形燃料電池セルスタック１４について説明する。図４は、固体酸化物形燃料電池システムの固体酸化物形燃料電池セルスタックを示す斜視図である。図４に示すように、固体酸化物形燃料電池セルスタック１４は、１６本の固体酸化物形燃料電池セルユニット１６を備え、これらの固体酸化物形燃料電池セルユニット１６の下端側及び上端側が、それぞれ、固体酸化物形セラミック製の下支持板６８及び上支持板１００により支持されている。これらの下支持板６８及び上支持板１００には、内側電極端子８６が貫通可能な貫通穴６８ａ及び１００ａがそれぞれ形成されている。 Next, the solid oxide fuel cell stack 14 will be described with reference to FIG. FIG. 4 is a perspective view showing a solid oxide fuel cell stack of a solid oxide fuel cell system. As shown in FIG. 4, the solid oxide fuel cell stack 14 includes 16 solid oxide fuel cell units 16, and the lower end side and the upper end side of these solid oxide fuel cell units 16 are provided. , Each of which is supported by a lower support plate 68 and an upper support plate 100 made of solid oxide ceramic. Through holes 68a and 100a through which the inner electrode terminal 86 can penetrate are formed in the lower support plate 68 and the upper support plate 100, respectively.
さらに、固体酸化物形燃料電池セルユニット１６には、集電体１０２及び外部端子１０４が取り付けられている。この集電体１０２は、燃料極である内側電極９０に取り付けられた内側電極端子８６と電気的に接続される燃料極用接続部１０２ａと、空気極である外側電極９２の外周面全体と電気的に接続される空気極用接続部１０２ｂとにより一体的に形成されている。空気極用接続部１０２ｂは、外側電極９２の表面を上下方向に延びる鉛直部１０２ｃと、この鉛直部１０２ｃから外側電極９２の表面に沿って水平方向に延びる多数の水平部１０２ｄとから形成されている。また、燃料極用接続部１０２ａは、空気極用接続部１０２ｂの鉛直部１０２ｃから固体酸化物形燃料電池セルユニット１６の上下方向に位置する内側電極端子８６に向って斜め上方又は斜め下方に向って直線的に延びている。 Further, a current collector 102 and an external terminal 104 are attached to the solid oxide fuel cell unit 16. The current collector 102 is electrically connected to the fuel electrode connection portion 102a that is electrically connected to the inner electrode terminal 86 attached to the inner electrode 90 that is the fuel electrode, and the entire outer peripheral surface of the outer electrode 92 that is the air electrode. It is integrally formed with the air electrode connecting portion 102b which is connected to the air electrode. The air electrode connecting portion 102b is formed of a vertical portion 102c extending in the vertical direction on the surface of the outer electrode 92 and a large number of horizontal portions 102d extending in the horizontal direction from the vertical portion 102c along the surface of the outer electrode 92. There is. Further, the fuel electrode connecting portion 102a faces diagonally upward or diagonally downward from the vertical portion 102c of the air electrode connecting portion 102b toward the inner electrode terminal 86 located in the vertical direction of the solid oxide fuel cell unit 16. It extends linearly.
さらに、固体酸化物形燃料電池セルスタック１４の端（図５では左端の奥側及び手前側）に位置する２個の固体酸化物形燃料電池セルユニット１６の上側端及び下側端の内側電極端子８６には、それぞれ外部端子１０４が接続されている。これらの外部端子１０４は、隣接する固体酸化物形燃料電池セルスタック１４の端にある固体酸化物形燃料電池セルユニット１６の外部端子１０４（図示せず）に接続され、上述したように、１６０本の固体酸化物形燃料電池セルユニット１６の全てが直列接続されるようになっている。 Further, the inner electrodes of the upper end and the lower end of the two solid oxide fuel cell units 16 located at the ends of the solid oxide fuel cell stack 14 (the back side and the front side of the left end in FIG. 5). External terminals 104 are connected to the terminals 86, respectively. These external terminals 104 are connected to the external terminals 104 (not shown) of the solid oxide fuel cell unit 16 at the end of the adjacent solid oxide fuel cell stack 14, and as described above, 160. All of the solid oxide fuel cell unit 16 of the book are connected in series.
次に図６により固体酸化物形燃料電池セルユニット１６について説明する。図６は、固体酸化物形燃料電池システムの固体酸化物形燃料電池セルユニットを示す部分断面図である。図６に示すように、固体酸化物形燃料電池セルユニット１６は、固体酸化物形燃料電池セル８４と、この固体酸化物形燃料電池セル８４の上下方向端部にそれぞれ接続された内側電極端子８６とを備えている。固体酸化物形燃料電池セル８４は、上下方向に延びる管状構造体であり、内部に燃料ガス流路８８を形成する円筒形の多孔質支持体９１上に内側電極９０と、外側電極９２と、内側電極９０と外側電極９２との間にある電解質層９４とを備えている。 Next, the solid oxide fuel cell unit 16 will be described with reference to FIG. FIG. 6 is a partial cross-sectional view showing a solid oxide fuel cell cell unit of a solid oxide fuel cell system. As shown in FIG. 6, the solid oxide fuel cell unit 16 has an inner electrode terminal connected to the solid oxide fuel cell 84 and the vertical end portions of the solid oxide fuel cell 84, respectively. It is equipped with 86. The solid oxide fuel cell 84 is a tubular structure extending in the vertical direction, and has an inner electrode 90, an outer electrode 92, and an inner electrode 90 on a cylindrical porous support 91 forming a fuel gas flow path 88 inside. An electrolyte layer 94 is provided between the inner electrode 90 and the outer electrode 92.
固体酸化物形燃料電池セル８４の上端側と下端側に取り付けられた内側電極端子８６は、同一構造であるため、ここでは、上端側に取り付けられた内側電極端子８６について具体的に説明する。内側電極９０の上部９０ａは、電解質層９４と外側電極９２に対して露出された外周面９０ｂと上端面９０ｃとを備えている。内側電極端子８６は、導電性のシール材９６を介して内側電極９０の外周面９０ｂと接続され、さらに、内側電極９０の上端面９０ｃとは直接接触することにより、内側電極９０と電気的に接続されている。内側電極端子８６の中心部には、内側電極９０の燃料ガス流路８８と連通する燃料ガス流路９８が形成されている。固体酸化物形燃料電池セル８４として本発明の固体酸化物形燃料電池セルを用いる。 Since the inner electrode terminals 86 attached to the upper end side and the lower end side of the solid oxide fuel cell 84 have the same structure, the inner electrode terminals 86 attached to the upper end side will be specifically described here. The upper portion 90a of the inner electrode 90 includes an outer peripheral surface 90b and an upper end surface 90c exposed to the electrolyte layer 94 and the outer electrode 92. The inner electrode terminal 86 is connected to the outer peripheral surface 90b of the inner electrode 90 via a conductive sealing material 96, and further, by directly contacting the upper end surface 90c of the inner electrode 90, the inner electrode terminal 86 is electrically contacted with the inner electrode 90. It is connected. At the center of the inner electrode terminal 86, a fuel gas flow path 98 communicating with the fuel gas flow path 88 of the inner electrode 90 is formed. The solid oxide fuel cell of the present invention is used as the solid oxide fuel cell 84.
次に、図に示された燃料電池システムの起動モードについて説明する。先ず、改質用空気を増やすように改質用空気流量調整ユニット４４、電磁弁４２及び混合部４７を制御し、改質器２０に空気を供給する。また、発電室１０には、発電用空気流量調整ユニット４５、電磁弁４２を制御し、空気導入管７６から発電用の空気が供給される。そしてまた、燃料ガスの供給を増やすように燃料流量調整ユニット３８、及び混合部４７を制御し、改質器２０に被改質ガスを供給し、改質器２０へ送り込まれた被改質ガス及び改質用空気は、改質器２０、燃料ガス供給管６４、ガスマニホールド６６を介して、各々の貫通孔６９から各燃料電池セルユニット１６内に送り込まれる。各燃料電池セルユニット１６内に送り込まれた被改質ガス及び改質用空気は、各燃料電池セルユニット１６の下端に形成されている燃料ガス流路９８から燃料ガス流路８８を通過し、上端に形成されている燃料ガス流路９８から夫々流出する。その後、点火装置８３によって、燃料ガス流路９８上端から流出した被改質ガスに着火して燃焼運転を実行する。これにより、燃焼室１８内で被改質ガスが燃焼され、部分酸化改質反応が発生する。 Next, the start mode of the fuel cell system shown in the figure will be described. First, the reforming air flow rate adjusting unit 44, the solenoid valve 42, and the mixing unit 47 are controlled so as to increase the reforming air, and the air is supplied to the reformer 20. Further, the power generation chamber 10 is controlled by the power generation air flow rate adjusting unit 45 and the solenoid valve 42, and air for power generation is supplied from the air introduction pipe 76. Further, the fuel flow adjustment unit 38 and the mixing unit 47 are controlled so as to increase the supply of the fuel gas, the reformed gas is supplied to the reformer 20, and the reformed gas sent to the reformer 20. And the reforming air is sent into each fuel cell unit 16 from each through hole 69 through the reformer 20, the fuel gas supply pipe 64, and the gas manifold 66. The reformed gas and the reforming air sent into each fuel cell unit 16 pass through the fuel gas flow path 88 from the fuel gas flow path 98 formed at the lower end of each fuel cell cell unit 16. Each flows out from the fuel gas flow path 98 formed at the upper end. After that, the ignition device 83 ignites the reformed gas flowing out from the upper end of the fuel gas flow path 98 to execute the combustion operation. As a result, the reformed gas is burned in the combustion chamber 18, and a partial oxidation reforming reaction occurs.
その後、改質器２０の温度が約６００℃以上になり、且つ燃料電池セル集合体１２の温度が約２５０℃を超えたことを条件として、オートサーマル改質反応へと移行させる。この時、水流量調整ユニット２８、燃料流量調整ユニット３８及び改質用空気流量調整ユニット４４により、被改質ガスと改質用空気と水蒸気とを予め混合したガスを改質器２０に供給する。次いで、改質器２０の温度が６５０℃以上となり、且つ燃料電池セル集合体１２の温度が約６００℃を超えたことを条件として、水蒸気改質反応へと移行させる。 After that, the process proceeds to the autothermal reforming reaction on condition that the temperature of the reformer 20 exceeds about 600 ° C. and the temperature of the fuel cell assembly 12 exceeds about 250 ° C. At this time, the water flow rate adjusting unit 28, the fuel flow rate adjusting unit 38, and the reforming air flow rate adjusting unit 44 supply the reformer 20 with a gas in which the reformed gas, the reforming air, and steam are mixed in advance. .. Next, the process proceeds to the steam reforming reaction on condition that the temperature of the reformer 20 exceeds 650 ° C. and the temperature of the fuel cell assembly 12 exceeds about 600 ° C.
上述したように着火から燃焼工程の進行に合わせて改質工程を切り替えていくことで、発電室１０内の温度が徐々に上昇する。発電室１０の温度が、燃料電池モジュール２を安定的に作動させる定格温度（約７００℃）よりも低い所定の発電温度に達したら、燃料電池モジュール２を含む電気回路を閉じる。それにより、燃料電池モジュール２は発電を開始し、回路に電流が流れて外部に電力を供給することができる。 As described above, by switching the reforming process from ignition to the progress of the combustion process, the temperature in the power generation chamber 10 gradually rises. When the temperature of the power generation chamber 10 reaches a predetermined power generation temperature lower than the rated temperature (about 700 ° C.) for stably operating the fuel cell module 2, the electric circuit including the fuel cell module 2 is closed. As a result, the fuel cell module 2 starts power generation, and a current flows through the circuit to supply electric power to the outside.
次に、本実施形態による固体酸化物形燃料電池システムの運転停止について説明する。燃料電池システムの運転停止は、燃料電池モジュールからの電力の取り出しを停止させた後も燃料の供給を継続しながら、冷却用の空気を大量に送ることにより燃料電池セルスタックを冷却する。次に、セルスタックの温度が燃料電池セルの燃料極の酸化温度未満に低下したときの燃料の供給を停止させ、以降、温度が十分に低下するまでの冷却用の空気のみを供給を続け、燃料電池に完全に停止させることができる。 Next, the shutdown of the solid oxide fuel cell system according to the present embodiment will be described. The shutdown of the fuel cell system cools the fuel cell stack by sending a large amount of cooling air while continuing to supply fuel even after stopping the extraction of electric power from the fuel cell module. Next, when the temperature of the cell stack drops below the oxidation temperature of the fuel electrode of the fuel cell, the supply of fuel is stopped, and thereafter, only the cooling air is supplied until the temperature drops sufficiently. It can be completely stopped by the fuel cell.
また、緊急時には、電力の取り出し、燃料ガス、空気及び燃料改質用の水の供給をほぼ同時に遮断する、シャットダウン停止により燃料電池システムを停止させることができる。また、電力の取り出しを停止させた後も燃料を少しずつ絞りながら停止したり、Ｎ2ガスなどのパージガスを流すことなく停止することが可能である。 Also, in an emergency, the fuel cell system can be shut down by shutting off power, fuel gas, air and water for reforming at about the same time. In addition, even after stopping the extraction of electric power, it is possible to stop while squeezing the fuel little by little, or to stop without flowing a purge gas such as N 2 gas.
シャットダウン停止のほぼ同時に遮断するとは、電流、空気、ガス、水が数１０秒以内という非常に短い時間にて全て停止することを示す。例えば、電流、空気、ガス、水がほぼ同時に全て停止する場合や、電流を止めたのち１０数秒後に空気と燃料ガスの供給を止め、さらにその１０数秒後に水の供給を止める場合が挙げられる。 Shutdown Shutdown almost at the same time means that the current, air, gas, and water all stop within a very short time of several tens of seconds. For example, there are cases where the electric current, air, gas, and water all stop at almost the same time, and cases where the supply of air and fuel gas is stopped 10 seconds after the current is stopped, and then the water supply is stopped 10 seconds later.
本発明を以下の実施例によってさらに詳細に説明するが、本発明はこれら実施例に限定されるものではない。 The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
［実施例１］
［ＹＳＺ原料］
共沈法で作製した。具体的には、イットリアの溶解液を８ｍｏｌ％になるように塩化ジルコニウム溶液に混合し、ゾル化後、脱水、遠心分離し、１００℃乾燥により非晶質水和ジルコニアを得た。得られた非晶質水和ジルコニアを乾式粉砕後、８００℃、２時間で焼成し、Ｄ１０：４．５μｍ、Ｄ５０：１５μｍ、Ｄ９０：６２μｍの粉末（ＢＥＴ：６ｍ2／ｇ）を得た。
[Example 1]
[YSZ raw material]
It was prepared by the coprecipitation method. Specifically, the yttria solution was mixed with a zirconium chloride solution to a concentration of 8 mol%, solified, dehydrated and centrifuged, and dried at 100 ° C. to obtain amorphous hydrated zirconia. The obtained amorphous hydrated zirconia was dry-pulverized and calcined at 800 ° C. for 2 hours to obtain powders (BET: 6 m 2 / g) having D10: 4.5 μm, D50: 15 μm, and D90: 62 μm.
［多孔質支持体用坏土：燃料極導電部］
ＮｉＯ粉末（ＢＥＴ：３．２ｍ2／ｇ、Ｄ１０：０．３２μｍ、Ｄ５０：０．４７μｍ、Ｄ９０：０．７７μｍ）７２．５重量部とＹＳＺ粉末（８モルＹ2Ｏ3含有安定化ＺｒＯ2、ＢＥＴ：６ｍ2／ｇ、Ｄ１０：４．５μｍ、Ｄ５０：１５μｍ、Ｄ９０：６２μｍ）２７．５重量部の合計１００重量部を溶媒（水）１０重量部、バインダー（メチルセルロース系水溶性高分子）７重量部、潤滑剤０．１重量部、乾燥防止剤３．５重量部を計量し、偏りがないようにミキサー混合後、混練器（ニーダー）で混練し、真空土練装置で脱気し、押し出し成形用の坏土を調製した。
[Soil for porous support: Fuel electrode conductive part]
NiO powder (BET: 3.2 m 2 / g, D10: 0.32 μm, D50: 0.47 μm, D90: 0.77 μm) 72.5 parts by weight and YSZ powder (8 mol Y 2 O 3 content stabilized ZrO 2) , BET: 6 m 2 / g, D10: 4.5 μm, D50: 15 μm, D90: 62 μm) 27.5 parts by weight, totaling 100 parts by weight, 10 parts by weight of powder (water), binder (methyl cellulose-based water-soluble polymer) Weigh 7 parts by weight, 0.1 part by weight of lubricant, and 3.5 parts by weight of anti-drying agent, mix with a mixer so that there is no bias, knead with a kneader, and degas with a vacuum clay kneader. , The clay for extrusion molding was prepared.
［燃料極触媒層用スラリーの作製］
ＮｉＯとＧＤＣ１０（１０ｍｏｌ％Ｇｄ2Ｏ3−９０ｍｏｌ％ＣｅＯ2）の混合物を共沈法で作製後、熱処理を行い燃料極触媒層粉末を得た。ＮｉＯとＧＤＣ１０の混合比は重量比で５０／５０とした。平均粒子径は０．５μｍとなるように調節した。該粉末２０重量部を溶媒（エタノール）１００重量部、バインダー（エチルセルロース）２重量部、分散剤（ノニオン性界面活性剤）１重量部と混合した後、十分攪拌してスラリーを調製した。なお、「１０ｍｏｌ％Ｇｄ2Ｏ3−９０ｍｏｌ％ＣｅＯ2」は、Ｇｄ原子及びＣｅ原子の総量に対する、Ｇｄ原子の濃度が１０ｍｏｌ％、Ｃｅ原子の濃度が９０ｍｏｌ％であることを意味する。
[Preparation of slurry for fuel electrode catalyst layer]
After making a mixture of NiO and GDC10 (10mol% Gd 2 O 3 -90mol% CeO 2) with a coprecipitation method, to obtain a fuel electrode catalyst layer powder subjected to heat treatment. The mixing ratio of NiO and GDC10 was 50/50 by weight. The average particle size was adjusted to 0.5 μm. A slurry was prepared by mixing 20 parts by weight of the powder with 100 parts by weight of a solvent (ethanol), 2 parts by weight of a binder (ethyl cellulose), and 1 part by weight of a dispersant (nonionic surfactant), and then sufficiently stirring the mixture. Incidentally, "10mol% Gd 2 O 3 -90mol% CeO 2 " is the total amount of Gd atoms and Ce atoms, the concentration of Gd atoms 10 mol%, the concentration of Ce atoms is meant to be 90 mol%.
［反応抑制層用スラリーの作製］
反応抑制層の材料として、セリウム系複合酸化物（ＬＤＣ４０。すなわち、４０ｍｏｌ％のＬａ2Ｏ3−６０ｍｏｌ％のＣｅＯ2）の粉末１０重量部を用いた。焼結助剤としてＧａ2Ｏ3粉末を０．０４重量部混合し、さらに溶媒（エタノール）１００重量部、バインダー（エチルセルロース）２重量部、分散剤（ノニオン性界面活性剤）１重量部と混合した後、十分攪拌してスラリーを調製した。なお、「４０ｍｏｌ％のＬａ2Ｏ3−６０ｍｏｌ％のＣｅＯ2」は、Ｌａ原子及びＣｅ原子の総量に対する、Ｌａ原子の濃度が４０ｍｏｌ％、Ｃｅ原子の濃度が６０ｍｏｌ％であることを意味する。
[Preparation of slurry for reaction suppression layer]
As the material of the inhibition layer, cerium complex oxide (LDC40. I.e., CeO 2 of 40 mol% of La 2 O 3 -60mol%) powders were used 10 parts by weight of. 0.04 parts by weight of Ga 2 O 3 powder is mixed as a sintering aid, and further mixed with 100 parts by weight of a solvent (ethanol), 2 parts by weight of a binder (ethyl cellulose), and 1 part by weight of a dispersant (nonionic surfactant). After that, the mixture was sufficiently stirred to prepare a slurry. Note that "40 mol% of La 2 O 3 -60mol% of CeO 2" is the total amount of La atoms and Ce atoms, the concentration of La atoms 40 mol%, the concentration of Ce atoms is meant to be 60 mol%.
［固体電解質層用スラリーの作製］
固体電解質層の材料として、Ｌａ0.9Ｓｒ0.1Ｇａ0.8Ｍｇ0.2Ｏ3の組成のＬＳＧＭ粉末を用いた。ＬＳＧＭ粉末４０重量部を溶媒（エタノール）１００重量部、バインダー（エチルセルロース）２重量部、分散剤（ノニオン性界面活性剤）１重量部と混合した後、十分攪拌してスラリーを調製した。
[Preparation of slurry for solid electrolyte layer]
As the material of the solid electrolyte layer, LSGM powder having a composition of La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 was used. A slurry was prepared by mixing 40 parts by weight of the LSGM powder with 100 parts by weight of the solvent (ethanol), 2 parts by weight of the binder (ethyl cellulose), and 1 part by weight of the dispersant (nonionic surfactant), and then sufficiently stirring the mixture.
［空気極触媒層用スラリーの作製］
空気極の材料として、Ｌａ0.6Ｓｒ0.4Ｃｏ0.2Ｆｅ0.8Ｏ3の組成の粉末を用いた。該粉末４０重量部を溶媒（エタノール）１００重量部、バインダー（エチルセルロース）２重量部、分散剤（ノニオン性界面活性剤）１重量部と混合した後、十分攪拌してスラリーを調製した。
[Preparation of slurry for air electrode catalyst layer]
As the material of the air electrode, a powder having a composition of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 was used. A slurry was prepared by mixing 40 parts by weight of the powder with 100 parts by weight of a solvent (ethanol), 2 parts by weight of a binder (ethyl cellulose), and 1 part by weight of a dispersant (nonionic surfactant), and then sufficiently stirring the mixture.
［固体酸化物形燃料電池セルの作製］
上記のようにして得られた坏土並びに各スラリーを用いて、以下の方法で固体酸化物形燃料電池セルを作製した。
前記多孔質支持体用坏土から押出し成形法によって円筒状成形体を作製した。室温で乾燥した後、１０５０℃で２時間熱処理して多孔質支持体を作製した。この多孔質支持体上に、スラリーコート法により、燃料極触媒層、反応抑制層、固体電解質層の順番で成膜した。これら積層成形体を１３００℃で２時間共焼成した。次に、約１７ｃｍ2になるように固体電解質層の表面に空気極触媒層を成形し、１１００℃で２時間焼成した。なお、多孔質支持体は、共焼成後の寸法で、外径１０ｍｍ、肉厚１ｍｍとした。作製した固体酸化物形燃料電池セルは、燃料極触媒層の厚さが１０μｍであり、反応抑制層層の厚みが５μｍであり、固体電解質層の厚みが５０μｍであり、空気極触媒層の厚みが２０μｍである。
[Manufacturing of solid oxide fuel cell]
A solid oxide fuel cell was produced by the following method using the clay obtained as described above and each slurry.
A cylindrical molded body was produced from the porous support clay by an extrusion molding method. After drying at room temperature, heat treatment was performed at 1050 ° C. for 2 hours to prepare a porous support. A fuel electrode catalyst layer, a reaction suppression layer, and a solid electrolyte layer were formed on the porous support in this order by a slurry coating method. These laminated molded products were co-baked at 1300 ° C. for 2 hours. Next, an air electrode catalyst layer was formed on the surface of the solid electrolyte layer so as to be about 17 cm 2, and calcined at 1100 ° C. for 2 hours. The porous support had an outer diameter of 10 mm and a wall thickness of 1 mm in terms of dimensions after co-firing. The produced solid oxide fuel cell has a fuel electrode catalyst layer thickness of 10 μm, a reaction suppression layer layer thickness of 5 μm, a solid electrolyte layer thickness of 50 μm, and an air electrode catalyst layer thickness. Is 20 μm.
［空気極導電部の作製］
次に、空気極触媒層の上に空気極導電部用ペーストを塗布して空気極導電部を形成した。空気極導電部用ペーストの組成は、銀粉末と、パラジウム粉末と、ＬＳＣＦ粉末と、溶媒と、バインダーとを混合させたものとした。この空気極導電部用ペーストを、固体酸化物形燃料電池セルに塗布した後、乾燥機にて乾燥させ、室温にて冷却後、７００℃１時間焼成した。
[Manufacturing of air electrode conductive part]
Next, the paste for the air electrode conductive part was applied on the air electrode catalyst layer to form the air electrode conductive part. The composition of the paste for the air electrode conductive part was a mixture of silver powder, palladium powder, LSCF powder, a solvent, and a binder. This paste for the air electrode conductive part was applied to a solid oxide fuel cell, dried in a dryer, cooled at room temperature, and fired at 700 ° C. for 1 hour.
［燃料電池セルユニットの作製］
支持体（燃料極導電部）の両端部に集電体とガスシールを兼ね備えた導電性シール材を取付け、さらに前記支持体（燃料極導電部）の両端部に導電性シール材を覆うように内側電極端子を設け、燃料電池セルユニットを作製した。内側電極端子は燃料ガス流路となる燃料極支持体の内径より縮径し、前記セルのそれぞれの端部からセルの外方向に伸びる縮径部を有するものとした。
[Manufacturing of fuel cell unit]
A conductive sealing material that has both a current collector and a gas seal is attached to both ends of the support (fuel electrode conductive portion), and the conductive sealing material is covered on both ends of the support (fuel electrode conductive portion). A fuel cell cell unit was manufactured by providing an inner electrode terminal. The inner electrode terminal has a diameter reduced from the inner diameter of the fuel electrode support serving as a fuel gas flow path, and has a diameter reduced portion extending outward from each end of the cell.
［モジュールの作製］
前記燃料電池セルユニットを１６本一組とし、燃料極と空気極を接続するコネクタで１６本を直列につなぎスタック化した。前記スタックを１０組搭載し１６０本を直列に接続し、さらに改質器、空気配管、及び燃料配管を取付けた後にハウジングで囲み、固体酸化物形燃料電池モジュールを作製した。
[Making a module]
The fuel cell unit was made into a set of 16 units, and 16 units were connected in series by a connector connecting the fuel electrode and the air electrode to form a stack. Ten sets of the stacks were mounted, 160 of them were connected in series, and after the reformer, the air pipe, and the fuel pipe were attached, they were surrounded by a housing to prepare a solid oxide fuel cell module.
［固体酸化物形燃料電池システムの作製］
上記燃料電池モジュールを、固体酸化物形燃料電池システムに組み込んだ。
[Manufacturing of solid oxide fuel cell system]
The fuel cell module was incorporated into a solid oxide fuel cell system.
［モジュールから電気の取り出し］
燃料極側の集電は、燃料極の露出部に集電金属を銀ペーストで張り合わせて焼き付けた。空気極側の集電は、空気極表面に銀ペーストを塗布した後、空気極の端部に集電金属を銀ペーストで張り合わせて焼き付けた。
[Extracting electricity from the module]
For current collection on the fuel electrode side, a current collector metal was attached to the exposed part of the fuel electrode with silver paste and baked. For current collection on the air electrode side, a silver paste was applied to the surface of the air electrode, and then a current collector metal was attached to the end of the air electrode with the silver paste and baked.
［還元］
大気中、８００℃まで加熱し、温度保持されたことを確認してから窒素によるガス置換後、水素ガスに水蒸気濃度１０％になるように調整された還元ガスを燃料極に導入した。還元ガスの流量は燃料極支持体の流路を毎分５ｃｍから１０ｃｍのスピードで流れるように流量を調整した。還元処理は燃料極に含まれるＮｉＯの９８％以上がＮｉに還元されるまで継続した。
［ひずみ］
ＹＳＺ、Ｎｉそれぞれのひずみ率は０．０１％以下であった。
[reduction]
After heating to 800 ° C. in the atmosphere and confirming that the temperature was maintained, gas replacement with nitrogen was performed, and then a reducing gas adjusted to have a water vapor concentration of 10% was introduced into the fuel electrode. The flow rate of the reducing gas was adjusted so that it would flow through the flow path of the fuel electrode support at a speed of 5 cm to 10 cm per minute. The reduction treatment was continued until 98% or more of NiO contained in the fuel electrode was reduced to Ni.
[Strain]
The strain rates of YSZ and Ni were 0.01% or less.
［実施例２］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を７５重量部、ＹＳＺ粉末２５重量部の合計１００重量部にした以外は、実施例１と同じである。
［ひずみ］
ＹＳＺ、Ｎｉそれぞれのひずみ率は０．０１％以下であった。
[Example 2]
This is the same as in Example 1 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 75 parts by weight and 25 parts by weight of the YSZ powder, for a total of 100 parts by weight.
[Strain]
The strain rates of YSZ and Ni were 0.01% or less.
［実施例３］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を７０重量部、ＹＳＺ粉末３０重量部の合計１００重量部にした以外は、実施例１と同じである。
［ひずみ］
ＹＳＺ、Ｎｉそれぞれのひずみ率は０．０１％以下であった。
[Example 3]
This is the same as in Example 1 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 70 parts by weight and 30 parts by weight of the YSZ powder, for a total of 100 parts by weight.
[Strain]
The strain rates of YSZ and Ni were 0.01% or less.
［実施例４］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を６０重量部、ＹＳＺ粉末４０重量部の合計１００重量部にした以外は、実施例１と同じである。
［ひずみ］
ＹＳＺ、Ｎｉそれぞれのひずみ率は０．０１％以下であった。
[Example 4]
This is the same as in Example 1 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 60 parts by weight and 40 parts by weight of the YSZ powder, for a total of 100 parts by weight.
[Strain]
The strain rates of YSZ and Ni were 0.01% or less.
［実施例５］
還元条件の温度を７００℃にした以外は実施例２と同じである。
[Example 5]
It is the same as in Example 2 except that the temperature of the reduction condition is set to 700 ° C.
［実施例６］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を６７．５重量部、ＹＳＺ粉末３２．５重量部の合計１００重量部にした以外は、実施例１と同じである。
[Example 6]
This is the same as in Example 1 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 67.5 parts by weight and 32.5 parts by weight of the YSZ powder, for a total of 100 parts by weight.
［実施例７］
還元条件の温度を７００℃にした以外は実施例１と同じである。
[Example 7]
It is the same as that of Example 1 except that the temperature of the reduction condition is set to 700 ° C.
［実施例８］
ＹＳＺ原料及び多孔質支持体用坏土を以下のようにして調製した以外は実施例１と同じである。
［ＹＳＺ原料］
共沈法で作製した。具体的には、イットリアの溶解液を８ｍｏｌ％になるように塩化ジルコニウム溶液に混合し、ゾル化後、脱水、遠心分離し、１００℃乾燥により非晶質水和ジルコニアを得た。得られた非晶質水和ジルコニアを乾式粉砕後、８００℃、２時間で焼成して得られた粉体を湿式粉砕して乾燥後、１０００℃、１０時間追加焼成しＤ１０：１．２５μｍ、Ｄ５０：４４μｍ、Ｄ９０：６５μｍの粉末（ＢＥＴ：７．５ｍ2／ｇ）を得た。
[Example 8]
It is the same as that of Example 1 except that the YSZ raw material and the clay for the porous support were prepared as follows.
[YSZ raw material]
It was prepared by the coprecipitation method. Specifically, the yttria solution was mixed with a zirconium chloride solution to a concentration of 8 mol%, solified, dehydrated and centrifuged, and dried at 100 ° C. to obtain amorphous hydrated zirconia. The obtained amorphous hydrated zirconia was dry-pulverized and then calcined at 800 ° C. for 2 hours. The obtained powder was wet-pulverized and dried, and then additionally calcined at 1000 ° C. for 10 hours at D10: 1.25 μm. Powders of D50: 44 μm and D90: 65 μm (BET: 7.5 m 2 / g) were obtained.
［多孔質支持体用坏土：燃料極導電部］
ＮｉＯ粉末（ＢＥＴ：３．２ｍ2／ｇ、Ｄ１０：０．３２μｍ、Ｄ５０：０．４７μｍ、Ｄ９０：０．７７μｍ）５５重量部とＹＳＺ粉末（８モルＹ2Ｏ3含有安定化ＺｒＯ2、ＢＥＴ：７．５ｍ2／ｇ、Ｄ１０：１．２５μｍ、Ｄ５０：４４μｍ、Ｄ９０：６５μｍ）４５重量部の合計１００重量部を溶媒（水）１０重量部、バインダー（メチルセルロース系水溶性高分子）７重量部、潤滑剤０．１重量部、乾燥防止剤３．５重量部を計量し、偏りがないようにミキサー混合後、混練器（ニーダー）で混練し、真空土練装置で脱気し、押し出し成形用の坏土を調製した。
[Soil for porous support: Fuel electrode conductive part]
55 parts by weight of NiO powder (BET: 3.2 m 2 / g, D10: 0.32 μm, D50: 0.47 μm, D90: 0.77 μm) and YSZ powder (8 mol Y 2 O 3 containing stabilized ZrO 2 , BET) : 7.5 m 2 / g, D10: 1.25 μm, D50: 44 μm, D90: 65 μm) 45 parts by weight, totaling 100 parts by weight, 10 parts by weight of solvent (water), 7 parts by weight of binder (methylcellulose-based water-soluble polymer) Weigh parts, 0.1 part by weight of lubricant, and 3.5 parts by weight of anti-drying agent, mix with a mixer so that there is no bias, knead with a kneader (kneader), degas with a vacuum clay kneader, and extrude. A clay for molding was prepared.
［実施例９］
還元条件の温度を７００℃にした以外は実施例６と同じである。
[Example 9]
It is the same as in Example 6 except that the temperature of the reduction condition is set to 700 ° C.
［実施例１０］
還元条件の温度を７００℃にした以外は実施例３と同じである。
[Example 10]
It is the same as in Example 3 except that the temperature of the reduction condition is set to 700 ° C.
［実施例１１］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を５０重量部、ＹＳＺ粉末５０重量部の合計１００重量部にした以外は、実施例１と同じである。
[Example 11]
This is the same as in Example 1 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 50 parts by weight and 50 parts by weight of the YSZ powder, for a total of 100 parts by weight.
［実施例１２］
ＹＳＺ原料及び多孔質支持体用坏土を以下のようにして調製した以外は実施例１と同じである。
［ＹＳＺ原料］
共沈法で作製した。具体的には、イットリアの溶解液を８ｍｏｌ％になるように塩化ジルコニウム溶液に混合し、ゾル化後、脱水、遠心分離し、１００℃乾燥により非晶質水和ジルコニアを得た。得られた非晶質水和ジルコニアを実施例１と比較しより細かくなるまで乾式粉砕後、８００℃、２時間で焼成しＤ１０：２．５μｍ、Ｄ５０：６μｍ、Ｄ９０：１８μｍの粉末（ＢＥＴ：６．３ｍ2／ｇ）を得た。
［多孔質支持体用坏土：燃料極導電部］
ＮｉＯ粉末（ＢＥＴ：３．２ｍ2／ｇ、Ｄ１０：０．３２μｍ、Ｄ５０：０．４７μｍ、Ｄ９０：０．７７μｍ）５５重量部とＹＳＺ粉末（８モルＹ2Ｏ3含有安定化ＺｒＯ2、ＢＥＴ：７．５ｍ2／ｇ、Ｄ１０：１．２５μｍ、Ｄ５０：６μｍ、Ｄ９０：１８μｍ）４５重量部の合計１００重量部を溶媒（水）１０重量部、バインダー（メチルセルロース系水溶性高分子）７重量部、潤滑剤０．１重量部、乾燥防止剤３．５重量部を計量し、偏りがないようにミキサー混合後、混練器（ニーダー）で混練し、真空土練装置で脱気し、押し出し成形用の坏土を調製した。
[Example 12]
It is the same as that of Example 1 except that the YSZ raw material and the clay for the porous support were prepared as follows.
[YSZ raw material]
It was prepared by the coprecipitation method. Specifically, the yttria solution was mixed with a zirconium chloride solution to a concentration of 8 mol%, solified, dehydrated and centrifuged, and dried at 100 ° C. to obtain amorphous hydrated zirconia. The obtained amorphous hydrated zirconia was dry-pulverized until it became finer than that of Example 1, and then calcined at 800 ° C. for 2 hours to obtain powders of D10: 2.5 μm, D50: 6 μm, and D90: 18 μm (BET: 6.3 m 2 / g) was obtained.
[Soil for porous support: Fuel electrode conductive part]
55 parts by weight of NiO powder (BET: 3.2 m 2 / g, D10: 0.32 μm, D50: 0.47 μm, D90: 0.77 μm) and YSZ powder (8 mol Y 2 O 3 containing stabilized ZrO 2 , BET) : 7.5m 2 / g, D10: 1.25μm, D50: 6μm, D90: 18μm) 45 parts by weight, totaling 100 parts by weight, 10 parts by weight of solvent (water), 7 parts by weight of binder (methylcellulose-based water-soluble polymer) Weigh parts, 0.1 part by weight of lubricant, and 3.5 parts by weight of anti-drying agent, mix with a mixer so that there is no bias, knead with a kneader (kneader), degas with a vacuum clay kneader, and extrude. A clay for molding was prepared.
［実施例１３］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を５５重量部、ＹＳＺ粉末４５重量部の合計１００重量部にした以外は、実施例１と同じである。
[Example 13]
This is the same as in Example 1 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 55 parts by weight and 45 parts by weight of the YSZ powder, for a total of 100 parts by weight.
［実施例１４］
還元条件の温度を７００℃にした以外は実施例４と同じである。
[Example 14]
It is the same as in Example 4 except that the temperature of the reduction condition is set to 700 ° C.
［実施例１５］
還元条件の温度を７００℃にした以外は実施例１３と同じである。
［ひずみ］
ＹＳＺ、Ｎｉそれぞれのひずみ率は０．０２％であった。
[Example 15]
It is the same as in Example 13 except that the temperature of the reduction condition is set to 700 ° C.
[Strain]
The strain rates of YSZ and Ni were 0.02%.
［実施例１６］
還元条件の温度を７００℃にした以外は実施例１１と同じである。
［ひずみ］
ＹＳＺ、Ｎｉそれぞれのひずみ率は０．０２％であった。
[Example 16]
It is the same as in Example 11 except that the temperature of the reduction condition is set to 700 ° C.
[Strain]
The strain rates of YSZ and Ni were 0.02%.
［実施例１７］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を６０重量部、ＹＳＺ粉末４０重量部の合計１００重量部にした以外は、実施例１２と同じである。
[Example 17]
This is the same as in Example 12 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 60 parts by weight and 40 parts by weight of the YSZ powder, for a total of 100 parts by weight.
［実施例１８］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を６０重量部、ＹＳＺ粉末４０重量部の合計１００重量部にした以外は、実施例８と同じである。
[Example 18]
This is the same as in Example 8 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 60 parts by weight and 40 parts by weight of the YSZ powder, for a total of 100 parts by weight.
［実施例１９］
多孔質支持体用坏土を以下のようにして調製した以外は実施例１０と同じである。
［多孔質支持体用坏土：燃料極導電部］
ＮｉＯ粉末（ＢＥＴ：３．２ｍ2／ｇ、Ｄ１０：０．３２μｍ、Ｄ５０：０．４７μｍ、Ｄ９０：０．７７μｍ）７０重量部とＹＳＺ粉末（８モルＹ2Ｏ3含有安定化ＺｒＯ2、ＢＥＴ：７．５ｍ2／ｇ、Ｄ１０：１．２５μｍ、Ｄ５０：６μｍ、Ｄ９０：１８μｍ）３０重量部の合計１００重量部を溶媒（水）１０重量部、造孔剤（アクリル系樹脂、平均粒子径８μｍ）４重量部、バインダー（メチルセルロース系水溶性高分子）７重量部、潤滑剤０．１重量部、乾燥防止剤３．５重量部を計量し、偏りがないようにミキサー混合後、混練器（ニーダー）で混練し、真空土練装置で脱気し、押し出し成形用の坏土を調製した。
[Example 19]
It is the same as in Example 10 except that the clay for the porous support was prepared as follows.
[Soil for porous support: Fuel electrode conductive part]
70 parts by weight of NiO powder (BET: 3.2 m 2 / g, D10: 0.32 μm, D50: 0.47 μm, D90: 0.77 μm) and YSZ powder (8 mol Y 2 O 3 content stabilized ZrO 2 , BET) : 7.5 m 2 / g, D10: 1.25 μm, D50: 6 μm, D90: 18 μm) 30 parts by weight, total 100 parts by weight, 10 parts by weight of solvent (water), pore-forming agent (acrylic resin, average particle size) 8 μm) 4 parts by weight, 7 parts by weight of binder (methyl cellulose-based water-soluble polymer), 0.1 parts by weight of lubricant, 3.5 parts by weight of anti-drying agent are weighed, mixed with a mixer so as not to be biased, and then kneaded. It was kneaded with (kneader) and degassed with a vacuum clay kneader to prepare a clay for extrusion molding.
［実施例２０］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を６０重量部、ＹＳＺ粉末４０重量部の合計１００重量部にし、還元条件の温度を８００℃にした以外は、実施例８と同じである。
[Example 20]
Same as Example 8 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part was 60 parts by weight and 40 parts by weight of the YSZ powder, totaling 100 parts by weight, and the temperature of the reduction condition was 800 ° C. Is.
［実施例２１］
多孔質支持体用坏土を以下のようにして調製した以外は実施例１と同じである。
［多孔質支持体用坏土：燃料極導電部］
ＮｉＯ粉末（ＢＥＴ：３．２ｍ2／ｇ、Ｄ１０：０．３２μｍ、Ｄ５０：０．４７μｍ、Ｄ９０：０．７７μｍ）６０重量部とＹ２Ｏ３粉末（ＢＥＴ：７．５ｍ2／ｇ、Ｄ１０：２．２５μｍ、Ｄ５０：４．４μｍ、Ｄ９０：７．７μｍ）４０重量部の合計１００重量部を溶媒（水）１０重量部、バインダー（メチルセルロース系水溶性高分子）７重量部、潤滑剤０．１重量部、乾燥防止剤３．５重量部を計量し、偏りがないようにミキサー混合後、混練器（ニーダー）で混練し、真空土練装置で脱気し、押し出し成形用の坏土を調製した。
[Example 21]
It is the same as in Example 1 except that the clay for the porous support was prepared as follows.
[Soil for porous support: Fuel electrode conductive part]
NiO powder (BET: 3.2m 2 /g,D10:0.32μm,D50:0.47μm,D90:0.77μm)60 parts by weight Y2O3 powder (BET: 7.5m 2 / g, D10: 2. 25 μm, D50: 4.4 μm, D90: 7.7 μm) 40 parts by weight, totaling 100 parts by weight, 10 parts by weight of solvent (water), 7 parts by weight of binder (methyl cellulose water-soluble polymer), 0.1 weight of lubricant Weighed 3.5 parts by weight of the anti-drying agent, mixed with a mixer so that there was no bias, kneaded with a kneader (kneader), degassed with a vacuum clay kneader, and prepared clay for extrusion molding. ..
［比較例１］
Ｙ２Ｏ３原料を以下のようにして調製し、還元条件の温度を７００℃にした以外は実施例２１と同じである。
［Ｙ２Ｏ３原料］
Ｙ２Ｏ３粉末（ＢＥＴ：８．２ｍ2／ｇ、Ｄ１０：０．４６μｍ、Ｄ５０：０．９μｍ、Ｄ９０：１．９μｍ）を用いた。
[Comparative Example 1]
The Y2O3 raw material was prepared as follows, and was the same as in Example 21 except that the temperature under the reduction conditions was set to 700 ° C.
[Y2O3 raw material]
Y2O3 powder (BET: 8.2 m 2 / g, D10: 0.46 μm, D50: 0.9 μm, D90: 1.9 μm) was used.
［比較例２］
ＹＳＺ原料及び多孔質支持体用坏土を以下のようにして調製した以外は実施例１０と同じである。
［ＹＳＺ原料］
共沈法で作製した。具体的には、イットリアの溶解液を８ｍｏｌ％になるように塩化ジルコニウム溶液に混合し、ゾル化後、脱水、遠心分離し、１００℃乾燥により非晶質水和ジルコニアを得た。得られた非晶質水和ジルコニアを乾式粉砕後、８００℃、２時間で焼成し、得られた粉体を湿式粉砕、乾燥後Ｄ１０：０．１１μｍ、Ｄ５０：０．２６μｍ、Ｄ９０：２．５μｍの粉末（ＢＥＴ：９．２ｍ2／ｇ）を得た。
［多孔質支持体用坏土：燃料極導電部］
ＮｉＯ粉末（ＢＥＴ：３．２ｍ2／ｇ、Ｄ１０：０．３２μｍ、Ｄ５０：０．４７μｍ、Ｄ９０：０．７７μｍ）７０重量部とＹＳＺ粉末（ＢＥＴ：９．２ｍ2／ｇ、Ｄ１０：０．１１μｍ、Ｄ５０：０．２６μｍ、Ｄ９０：２．５μｍ）３０重量部の合計１００重量部と分散剤と純水溶媒をボールミルに加え、解砕して１次粒子化、スプレードライで乾燥させ、ＮｉＯとＹＳＺの均一混合粉を得た。そして得られた混合粉１００重量部に対して溶媒（水）１０重量部、バインダー（メチルセルロース系水溶性高分子）７重量部、潤滑剤０．１重量部、乾燥防止剤３．５重量部を計量し、偏りがないようにミキサー混合後、混練器（ニーダー）で混練し、真空土練装置で脱気し、押し出し成形用の坏土を調製した。
［ひずみ］
ＹＳＺ、Ｎｉのひずみ率はそれぞれ０．０９％、０．０８％であった。
[Comparative Example 2]
It is the same as in Example 10 except that the YSZ raw material and the clay for the porous support were prepared as follows.
[YSZ raw material]
It was prepared by the coprecipitation method. Specifically, the yttria solution was mixed with a zirconium chloride solution to a concentration of 8 mol%, solified, dehydrated and centrifuged, and dried at 100 ° C. to obtain amorphous hydrated zirconia. The obtained amorphous hydrated zirconia was dry-ground and then calcined at 800 ° C. for 2 hours. The obtained powder was wet-ground and dried, and then D10: 0.11 μm, D50: 0.26 μm, D90: 2. A 5 μm powder (BET: 9.2 m 2 / g) was obtained.
[Soil for porous support: Fuel electrode conductive part]
NiO powder (BET: 3.2m 2 /g,D10:0.32μm,D50:0.47μm,D90:0.77μm)70 parts and YSZ powder (BET: 9.2m 2 / g, D10: 0. 11 μm, D50: 0.26 μm, D90: 2.5 μm) 30 parts by weight in total, 100 parts by weight, dispersant and pure water solvent were added to the ball mill, crushed into primary particles, dried by spray drying, and NiO. And YSZ uniform mixed powder was obtained. Then, 10 parts by weight of the solvent (water), 7 parts by weight of the binder (methyl cellulose-based water-soluble polymer), 0.1 part by weight of the lubricant, and 3.5 parts by weight of the antidrying agent were added to 100 parts by weight of the obtained mixed powder. After weighing and mixing with a mixer so as not to be biased, the mixture was kneaded with a kneader (kneader) and degassed with a vacuum clay kneader to prepare a clay for extrusion molding.
[Strain]
The strain rates of YSZ and Ni were 0.09% and 0.08%, respectively.
［比較例３］
還元条件の温度を６００℃にした以外は実施例４と同じである。
[Comparative Example 3]
It is the same as in Example 4 except that the temperature of the reduction condition is set to 600 ° C.
［比較例４］
還元条件の温度を６００℃にした以外は実施例２と同じである。
[Comparative Example 4]
It is the same as in Example 2 except that the temperature of the reduction condition is set to 600 ° C.
［比較例５］
燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を６５重量部、ＹＳＺ粉末３５重量部の合計１００重量部にした以外は、比較例２と同じである。
［ひずみ］
ＹＳＺ、Ｎｉそれぞれのひずみ率は０．１％であった。
[Comparative Example 5]
It is the same as Comparative Example 2 except that the NiO powder of the clay for the porous support used for the fuel electrode conductive part is 65 parts by weight and 35 parts by weight of the YSZ powder, for a total of 100 parts by weight.
[Strain]
The strain rates of YSZ and Ni were 0.1%.
［比較例６］
ＹＳＺ原料を以下のようにして調製した以外は実施例１０と同じである。
［ＹＳＺ原料］
共沈法で作製した。具体的には、イットリアの溶解液を８ｍｏｌ％になるように塩化ジルコニウム溶液に混合し、ゾル化後、脱水、遠心分離し、１００℃乾燥により非晶質水和ジルコニアを得た。得られた非晶質水和ジルコニアを乾式粉砕後、８００℃、２時間で焼成し、得られた粉体を湿式粉砕、乾燥後Ｄ１０：０．２３μｍ、Ｄ５０：１．６μｍ、Ｄ９０：４．１９μｍの粉末（ＢＥＴ：５．２ｍ2／ｇ）を得た。
[Comparative Example 6]
It is the same as in Example 10 except that the YSZ raw material was prepared as follows.
[YSZ raw material]
It was prepared by the coprecipitation method. Specifically, the yttria solution was mixed with a zirconium chloride solution to a concentration of 8 mol%, solified, dehydrated and centrifuged, and dried at 100 ° C. to obtain amorphous hydrated zirconia. The obtained amorphous hydrated zirconia was dry-ground and then calcined at 800 ° C. for 2 hours. The obtained powder was wet-ground and dried, and then D10: 0.23 μm, D50: 1.6 μm, D90: 4. A 19 μm powder (BET: 5.2 m 2 / g) was obtained.
［比較例７］
還元条件の温度を７００℃にした以外は実施例８と同じである。
[Comparative Example 7]
It is the same as in Example 8 except that the temperature of the reduction condition is set to 700 ° C.
［比較例８］
ＮｉＯ原料を以下のようにして調製し、燃料極導電部に用いる多孔質支持体用坏土のＮｉＯ粉末を６０重量部、ＹＳＺ粉末４０重量部の合計１００重量部にした以外は比較例２と同じである。
［ＮｉＯ原料］
市販原料の、Ｄ１０：１．１５μｍ、Ｄ５０：３．１μｍ、Ｄ９０：４．４３μｍの粉末（ＢＥＴ：３．１ｍ2／ｇ）を利用した。
[Comparative Example 8]
The NiO raw material was prepared as follows, and the NiO powder of the porous support soil used for the fuel electrode conductive part was 60 parts by weight and 40 parts by weight of the YSZ powder, which was 100 parts by weight in total. It is the same.
[NiO raw material]
Commercially available raw material powders of D10: 1.15 μm, D50: 3.1 μm, and D90: 4.43 μm (BET: 3.1 m 2 / g) were used.
［比較例９］
ＹＳＺ原料を以下のようにして調製した以外は実施例１４と同じである。
［ＹＳＺ原料］
共沈法で作製した。具体的には、イットリアの溶解液を８ｍｏｌ％になるように塩化ジルコニウム溶液に混合し、ゾル化後、脱水、遠心分離し、１００℃乾燥により非晶質水和ジルコニアを得た。得られた非晶質水和ジルコニアを乾式粉砕後、８００℃、２時間で焼成し、得られた粉体にＡｌ２Ｏ３ゾルを０．２５％になるように加え、湿式粉砕、乾燥してＤ１０：０．１１μｍ、Ｄ５０：０．２６μｍ、Ｄ９０：２．４μｍの粉末（ＢＥＴ：９．０ｍ2／ｇ）を得た。
[Comparative Example 9]
It is the same as in Example 14 except that the YSZ raw material was prepared as follows.
[YSZ raw material]
It was prepared by the coprecipitation method. Specifically, the yttria solution was mixed with a zirconium chloride solution to a concentration of 8 mol%, solified, dehydrated and centrifuged, and dried at 100 ° C. to obtain amorphous hydrated zirconia. The obtained amorphous hydrated zirconia is pulverized by dry method and then calcined at 800 ° C. for 2 hours. Al2O3 sol is added to the obtained powder so as to be 0.25%, wet pulverized and dried to D10: Powders of 0.11 μm, D50: 0.26 μm, and D90: 2.4 μm (BET: 9.0 m 2 / g) were obtained.
［比較例１０］
ＮｉＯ原料を以下のようにして調製した以外は比較例８と同じである。
［ＮｉＯ原料］
市販原料の、Ｄ１０：０．３２μｍ、Ｄ５０：０．７μｍ、Ｄ９０：２．２μｍの粉末（ＢＥＴ：２．８６ｍ2／ｇ）を利用した。
[Comparative Example 10]
It is the same as Comparative Example 8 except that the NiO raw material was prepared as follows.
[NiO raw material]
Commercially available raw material powders of D10: 0.32 μm, D50: 0.7 μm, and D90: 2.2 μm (BET: 2.86 m 2 / g) were used.
［性能評価］
［単セルあたりの発電性能］
作製した固体酸化物形燃料電池システムの発電は脱硫触媒で通した都市ガスを用い、燃料利用率８０％、空気を酸化ガスに用い、空気利用率３０％、運転温度７００℃、電流密度０．３Ａ／ｃｍ2の条件での発電電位を測定し、１６０で割って１本あたりの発電電位を求めた。なお発電電位の測定は、定常温度（７００℃）で２４時間経過後に測定した。
［１０００時間性能劣化率］
単セルあたりの発電性能を求める条件と同じ条件で、発電開始から２４時間後の発電電位を初期電位（Ｖ0）、１０００時間の連続運転後の発電電位を耐久後電位（Ｖ）とし、以下の式で１０００時間性能劣化率（％）を算出した。
１０００時間性能劣化率＝（Ｖ0−Ｖ）／Ｖ0×１００
［緊急停止回数］
作製した固体酸化物形燃料電池システムを以下のように運転した後、緊急停止（シャットダウン）した。
初期電位の測定
単セルあたりの発電性能を求める条件と同じ条件で、発電開始から２４時間後の発電電位：初期電位（Ｖ0）を求めた。
固体酸化物形燃料電池システムの停止
固体酸化物形燃料電池システムの電流、燃料ガス、空気、水の供給をほぼ同時に遮断する、シャットダウン停止により固体酸化物形燃料電池システムを停止させた。
２回目以降の固体酸化物形燃料電池システムの発電
単セルあたりの発電性能を求める条件と同じ条件で運転し、運転中に発電電位を測定した。
２回目以降の固体酸化物形燃料電池システムの停止
定常温度（７００℃）で２時間運転したのち、固体酸化物形燃料電池システムの電流、燃料ガス、空気、水の供給をほぼ同時に遮断する、シャットダウン停止により固体酸化物形燃料電池システムを停止させた。
緊急停止回数の評価
初期電位（Ｖ0）から２％発電電位が低下するまでの回数を緊急停止回数とした。
［判定］
◎：単セルあたりの発電性能：０．８Ｖ以上
且つ、１０００時間性能劣化率０．０３％以内
且つ、緊急停止回数：４００回以上
×：単セルあたりの発電性能：０．７８０Ｖ以下
もしくは、１０００時間性能劣化率０．１％以上
且つ、緊急停止回数：２００回未満
○：上記以外
[Performance evaluation]
[Power generation performance per cell]
For the power generation of the produced solid oxide fuel cell system, city gas passed through a desulfurization catalyst is used, the fuel utilization rate is 80%, air is used as the oxidation gas, the air utilization rate is 30%, the operating temperature is 700 ° C., and the current density is 0. The power generation potential under the condition of 3 A / cm 2 was measured, and the power generation potential per one was obtained by dividing by 160. The power generation potential was measured at a steady temperature (700 ° C.) after 24 hours had elapsed.
[1000 hours performance deterioration rate]
Under the same conditions as the conditions for determining the power generation performance per single cell, the power generation potential 24 hours after the start of power generation is defined as the initial potential (V 0 ), and the power generation potential after 1000 hours of continuous operation is defined as the endurance post-durability potential (V). The 1000-hour performance deterioration rate (%) was calculated by the formula of.
1000 hours performance deterioration rate = (V 0 −V) / V 0 × 100
[Number of emergency stops]
After operating the produced solid oxide fuel cell system as follows, it was urgently stopped (shut down).
Measurement of initial potential Under the same conditions as for determining the power generation performance per single cell, the power generation potential 24 hours after the start of power generation: the initial potential (V 0 ) was determined.
Stopping the solid oxide fuel cell system The solid oxide fuel cell system was stopped by shutting off the current, fuel gas, air, and water supply of the solid oxide fuel cell system almost at the same time.
The operation was performed under the same conditions as for obtaining the power generation performance per power generation unit of the solid oxide fuel cell system from the second time onward, and the power generation potential was measured during the operation.
Stopping the solid oxide fuel cell system from the second time onward After operating at a steady temperature (700 ° C.) for 2 hours, the current, fuel gas, air, and water supply of the solid oxide fuel cell system are cut off almost at the same time. The solid oxide fuel cell system was shut down by stopping the shutdown.
Evaluation of the number of emergency stops The number of times from the initial potential (V 0 ) until the 2% power generation potential drops was defined as the number of emergency stops.
[Judgment]
⊚: Power generation performance per cell: 0.8V or more
Moreover, the performance deterioration rate for 1000 hours is within 0.03%.
And the number of emergency stops: 400 times or more ×: Power generation performance per single cell: 0.780V or less
Alternatively, the performance deterioration rate for 1000 hours is 0.1% or more.
And the number of emergency stops: less than 200 times ○: other than the above
［酸化度測定］
酸化度を測定するために、燃料極のみを大気中４００℃に３０分間暴露し、その前後の重量を計測し、以下の計算式により求めた。
δ＝（ａ＋ｂ−ｂ・Ｘ）・（Ｇ２／Ｇ１−１）／ｂ／Ｘ
Ｘ：ＮｉＯ比率
Ｇ１：燃料極の初期重量（単位：ｇ）
Ｇ２：４００℃に３０分間暴露させたあとの重量（単位：ｇ）
ａ：Ｎｉのモル質量（ｇ／ｍｏｌ）
ｂ：Ｏのモル質量（ｇ／ｍｏｌ）
[Oxidation degree measurement]
In order to measure the degree of oxidation, only the fuel electrode was exposed to the atmosphere at 400 ° C. for 30 minutes, and the weight before and after that was measured and calculated by the following formula.
δ = (a + bb ・ X) ・ (G2 / G1-1) / b / X
X: NiO ratio
G1: Initial weight of fuel electrode (unit: g)
G2: Weight after exposure to 400 ° C for 30 minutes (unit: g)
a: Molar mass of Ni (g / mol)
b: Molar mass of O (g / mol)
［粒径測定］
酸化物原料の体積１０％粒径（以下、Ｄ１０）、及びＮｉＯ原料の体積５０％粒径はＪＩＳ Ｒ １６２９にもとづき、日機装製マイクロトラックＭＴ３３００を用いて測定した。測定するにあたり、予め、各原料は分散剤を加えた純水に適量加え、超音波処理により予め分散させた。測定条件は以下の通りである。
測定時間：３０秒
計算モード：ＭＴ３０００II
体積頻度の累積が１０％になる粒子径をＤ１０、累積が５０％になる粒子径をＤ５０、累積が９０％になる粒子径をＤ９０とした。
図７のグラフは代表的な３つのＹＳＺ原料の粒度分布を示した。それぞれの値は以下の通りである。
実施例１ Ｄ１０＝４．５μｍ（ＢＥＴ＝６ｍ2／ｇ、Ｄ５０＝１５μｍ、Ｄ９０＝６２μｍ）
実施例８ Ｄ１０＝１．２５μｍ（ＢＥＴ＝７．５ｍ2／ｇ、Ｄ５０＝４４μｍ、Ｄ９０＝６５μｍ）
比較例２ Ｄ１０＝０．１１μｍ（ＢＥＴ＝９．２ｍ2／ｇ、Ｄ５０＝０．２６μｍ、Ｄ９０＝２．５μｍ）
[Measurement of particle size]
The volume 10% particle size of the oxide raw material (hereinafter referred to as D10) and the volume 50% particle size of the NiO raw material were measured using a Microtrack MT3300 manufactured by Nikkiso Co., Ltd. based on JIS R 1629. In the measurement, each raw material was added in an appropriate amount to pure water to which a dispersant was added, and dispersed in advance by ultrasonic treatment. The measurement conditions are as follows.
Measurement time: 30 seconds
Calculation mode: MT3000II
The particle size at which the cumulative volume frequency is 10% is D10, the particle size at which the cumulative volume is 50% is D50, and the particle size at which the cumulative volume is 90% is D90.
The graph of FIG. 7 shows the particle size distribution of three typical YSZ raw materials. Each value is as follows.
Example 1 D10 = 4.5 μm (BET = 6 m 2 / g, D50 = 15 μm, D90 = 62 μm)
Example 8 D10 = 1.25 μm (BET = 7.5 m 2 / g, D50 = 44 μm, D90 = 65 μm)
Comparative Example 2 D10 = 0.11 μm (BET = 9.2 m 2 / g, D50 = 0.26 μm, D90 = 2.5 μm)
［最大酸化物粒子径の測定］
還元したセルを切断、樹脂埋め、研磨後、ＳＥＭ−ＥＤＸ（Ｓ４１００：日立製作所製）で観察した。加速倍率は１５ＫＶ、２次電子画像である。燃料極のほぼ中央を観察した。
まず１００倍で大きな粒子を探し、５００倍に拡大する。２次電子画像ではＮｉとＹＳＺを区別することはできない。ＥＤＸでＺｒ元素であることを確認し、最大粒子径を計測した。以上の作業を３回繰り返し、ＹＳＺの最大粒子径とした。なお、比較例１から１０については粒子径が小さく５００倍の観察では粒子径を測定できない。そのため、５００倍で大きな粒子を探し、１００００倍に拡大し、最大粒子径を計測した。図８は実施例１の燃料極を１００倍で観察した１例である。図９は１００倍での観察の結果、もっとも大きな粒子を５００倍で拡大し、最大粒子径に赤線を引き、計測により３５μｍを得た。
[Measurement of maximum oxide particle size]
The reduced cells were cut, filled with resin, polished, and then observed with SEM-EDX (S4100: manufactured by Hitachi, Ltd.). The acceleration magnification is 15 KV, which is a secondary electron image. The center of the fuel electrode was observed.
First, look for large particles at 100 times and magnify them at 500 times. Ni and YSZ cannot be distinguished in the secondary electron image. It was confirmed by EDX that it was a Zr element, and the maximum particle size was measured. The above operation was repeated 3 times to obtain the maximum particle size of YSZ. In Comparative Examples 1 to 10, the particle size is small and the particle size cannot be measured by observing at 500 times. Therefore, a large particle was searched for at 500 times, enlarged at 10,000 times, and the maximum particle size was measured. FIG. 8 is an example in which the fuel electrode of Example 1 was observed at a magnification of 100 times. As a result of observation at 100 times in FIG. 9, the largest particle was magnified at 500 times, a red line was drawn at the maximum particle size, and 35 μm was obtained by measurement.
［ガス透過流束］
ガス透過流束を計測するために、燃料極のみを還元して計測した。ガス透過流束は単位時間に膜を透過する気体の量で、一般には以下の式で求める。
Ｊ＝Ｑ／（Ａｔ）
Ｊ：ガス透過流束
Ａ：膜面積
ｔ：時間
Ｑ：透過した気体の量
実施例では、円筒状の燃料極で、片端をゴム栓し、反対側から空気圧を印加して、以下の式で求めた。
Ｊ＝Ｖ×６０／１０００／Ａ
Ａ＝Ｒ×Ｌ×π
透過面積：Ａ（ｍ2）
外径：Ｒ（ｍｍ） φ１０ｍｍ
長さ：Ｌ（ｍｍ） １００ｍｍ
空気流量：Ｖ（Ｌ／分）
ガス透過流束：Ｊ（ｍ3／ｍ2／ｈｒ）
[Gas permeation flux]
In order to measure the gas permeation flux, only the fuel electrode was reduced and measured. The gas permeation flux is the amount of gas that permeates the membrane in a unit time, and is generally calculated by the following formula.
J = Q / (At)
J: Gas permeation flux
A: Membrane area
t: time
Q: Amount of permeated gas
In the example, a cylindrical fuel electrode was used, one end was rubber-plugged, and air pressure was applied from the other side to obtain the result by the following formula.
J = V × 60/1000 / A
A = R × L × π
Permeation area: A (m 2 )
Outer diameter: R (mm) φ10 mm
Length: L (mm) 100 mm
Air flow rate: V (L / min)
Gas permeation flux: J (m 3 / m 2 / hr)
［導電率測定］
多孔質支持体用坏土から押出し成形法によって得られる円筒状成形体を通常条件で焼成し、還元処理後、４端子法で計測した。評価条件は以下の通りである。
雰囲気 ：（Ｈ2＋３％Ｈ2Ｏ）とＮ2の混合ガス（混合比はＨ2：Ｎ2＝７：４（ｖｏｌ：ｖｏｌ））
測定温度 ：７００℃
電流 ：１Ａ
[Measurement of conductivity]
The cylindrical molded body obtained by the extrusion molding method from the clay for the porous support was fired under normal conditions, reduced, and then measured by the 4-terminal method. The evaluation conditions are as follows.
Atmosphere: (H 2 + 3% H 2 O) and N 2 mixed gas (mixing ratio is H 2 : N 2 = 7: 4 (vol: vol))
Measurement temperature: 700 ° C
Current: 1A
［ＹＳＺ格子定数のひずみ率及びＮｉ格子定数のひずみ率］
ＹＳＺ格子定数のひずみ率及びＮｉ格子定数のひずみ率は、支持体のＹＳＺ格子定数、Ｎｉ格子定数及び支持体を粉末化して計測したＹＳＺ格子定数、Ｎｉ格子定数から、次の式で求めた絶対値である。
ＹＳＺ格子定数のひずみ率：（支持体のＹＳＺ格子定数―粉末のＹＳＺ格子定数）/粉末のＹＳＺ格子定数×１００
Ｎｉ格子定数のひずみ率：（支持体のＮｉ格子定数―粉末のＮｉ格子定数）/粉末のＮｉ格子定数×１００
なお多孔質支持体のＹＳＺ格子定数、Ｎｉ格子定数は次に示す絵X線回折法を用いた。
装置 ：パナリティカル社製「機種名：Ｘ‘Ｐｅｒｔ ＰＲＯ」Ｘ線回折装置
検出器：検出素子が１００チャネルある半導体アレイ検出器
Ｘ線出力：（Ｃｕ封入管）管電圧４０ｋＶ−管電流４０ｍＡ
特性Ｘ線：Ｃｕ−Ｋα線
フィルタ：Ｎｉ
走査方法：ステップ・スキャンニング法（Ｓｃａｎｎｉｎｇ Ｓｔｅｐ Ｓｉｚｅ：０．０５度）
ビーム径：１ｍｍ
ひずみのない場合の格子定数は支持体を粉末にして得た。なお、ＹＳＺ、Ｎｉそれぞれの格子定数は次の指数（ｈｋｌ）の測定結果を用い最小二乗法で求めた。
ＹＳＺ：（１１１）（２００）（２２０）（３１１）（２２２）（４００）（３３１）
Ｎｉ：（１１１）（２００）（２２０）（３１１）（２２２）
[Strain rate of YSZ lattice constant and strain rate of Ni lattice constant]
The strain rate of the YSZ lattice constant and the strain rate of the Ni lattice constant are the absolute values obtained from the YSZ lattice constant of the support, the Ni lattice constant and the YSZ lattice constant measured by powdering the support, and the Ni lattice constant by the following equations. The value.
Strain rate of YSZ lattice constant: (YSZ lattice constant of support-YSZ lattice constant of powder) / YSZ lattice constant of powder x 100
Strain rate of Ni lattice constant: (Ni lattice constant of support-Ni lattice constant of powder) / Ni lattice constant of powder x 100
For the YSZ lattice constant and Ni lattice constant of the porous support, the following picture X-ray diffraction method was used.
Equipment: PANalytical "Model name: X'Pert PRO" X-ray diffractometer Detector: Semiconductor array detector with 100 channels of detection elements X-ray output: (Cu-encapsulated tube) Tube voltage 40 kV-tube current 40 mA
Characteristic X-ray: Cu-Kα ray Filter: Ni
Scanning method: Scanning Step Size: 0.05 degrees
Beam diameter: 1 mm
The lattice constant in the absence of strain was obtained by powdering the support. The lattice constants of YSZ and Ni were obtained by the least squares method using the measurement results of the following exponents (hkl).
YSZ: (111) (200) (220) (311) (222) (400) (331)
Ni: (111) (200) (220) (311) (222)
１ 固体酸化物形燃料電池システム
２ 固体酸化物形燃料電池モジュール
４ 補機ユニット
６ ハウジング
７ 断熱材
８ 密封空間
１０ 発電室
１２ 固体酸化物形燃料電池セル集合体
１４ 固体酸化物形燃料電池セルスタック
１６ 固体酸化物形燃料電池セルユニット
１８ 燃焼室
２０ 改質器
２２ 空気用熱交換器
２４ 水供給源
２８ 水流量調整ユニット
３０ 燃料供給源
３２ ガス遮断弁
３６ 脱硫器
３８ 燃料流量調整ユニット
４０ 空気供給源
４２ 電磁弁
４４ 改質用空気流量調整ユニット
４５ 発電用空気流量調整ユニット
４６ 第１ヒータ
４８ 第２ヒータ
５０ 温水製造装置
５２ 制御ボックス
５４ インバータ
６０ 純水導入管
６２ 被改質ガス導入管
６４ 燃料ガス供給管
６６ マニホールド
６８ 下支持板
７０ 空気集約室
７２ 空気分配室
７４ 空気流路管
７６ 空気導入管
８０ 排気ガス通路
８２ 排気ガス排出管
８３ 点火装置
８４ 燃料電池セル
８６ 内側電極端子
８８ 燃料ガス流路
９０ 内側電極
９１ 多孔質支持体
９２ 外側電極
９４ 電解質
１００ 上支持板
１０２ 集電体
1 Solid Oxide Fuel Cell System 2 Solid Oxide Fuel Cell Module 4 Auxiliary Unit 6 Housing 7 Insulation 8 Sealed Space 10 Power Generation Room 12 Solid Oxide Fuel Cell Cell Assembly 14 Solid Oxide Fuel Cell Cell Stack 16 Solid Oxide Fuel Cell Cell Unit 18 Combustion Chamber 20 Reformer 22 Air Heat Exchanger 24 Water Supply Source 28 Water Flow Control Unit 30 Fuel Supply Source 32 Gas Shutoff Valve 36 Desmelter 38 Fuel Flow Control Unit 40 Air Supply Source 42 Electromagnetic valve 44 Reform air flow adjustment unit 45 Power generation air flow adjustment unit 46 1st heater 48 2nd heater 50 Hot water production equipment 52 Control box 54 Inverter 60 Pure water introduction pipe 62 Reform gas introduction pipe 64 Fuel Gas supply pipe 66 Manifold 68 Lower support plate 70 Air consolidating chamber 72 Air distribution chamber 74 Air flow path pipe 76 Air introduction pipe 80 Exhaust gas passage 82 Exhaust gas discharge pipe 83 Ignition device 84 Fuel cell 86 Inner electrode terminal 88 Fuel gas flow Road 90 Inner electrode 91 Porous support 92 Outer electrode 94 Electrolyte 100 Upper support plate 102 Current collector
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003263991A (en) * | 2002-03-04 | 2003-09-19 | Sulzer Hexis Ag | Structure body for anode used in fuel cell |
| JP2012513096A (en) * | 2008-12-19 | 2012-06-07 | サン−ゴバン セラミックス アンド プラスティクス，インコーポレイティド | Reduction-oxidation resistant electrodes for solid oxide fuel cells |
| JP2013030359A (en) * | 2011-07-28 | 2013-02-07 | Kyocera Corp | Fuel cell device |
| JP2013101885A (en) * | 2011-11-09 | 2013-05-23 | Jx Nippon Oil & Energy Corp | Solid oxide fuel cell system and startup control method therefor |
| JP2014096199A (en) * | 2011-10-14 | 2014-05-22 | Ngk Insulators Ltd | Fuel battery cell |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003263991A (en) * | 2002-03-04 | 2003-09-19 | Sulzer Hexis Ag | Structure body for anode used in fuel cell |
| JP2012513096A (en) * | 2008-12-19 | 2012-06-07 | サン−ゴバン セラミックス アンド プラスティクス，インコーポレイティド | Reduction-oxidation resistant electrodes for solid oxide fuel cells |
| JP2013030359A (en) * | 2011-07-28 | 2013-02-07 | Kyocera Corp | Fuel cell device |
| JP2014096199A (en) * | 2011-10-14 | 2014-05-22 | Ngk Insulators Ltd | Fuel battery cell |
| JP2013101885A (en) * | 2011-11-09 | 2013-05-23 | Jx Nippon Oil & Energy Corp | Solid oxide fuel cell system and startup control method therefor |
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