JP4280974B2

JP4280974B2 - Fuel cell system

Info

Publication number: JP4280974B2
Application number: JP2003081112A
Authority: JP
Inventors: 俊哉阿部; 正宏黒石; 弘明竹内; 進相川; 賢太郎鈴木; 幸作藤永; 健斎藤
Original assignee: Toto Ltd
Current assignee: Toto Ltd
Priority date: 2003-03-24
Filing date: 2003-03-24
Publication date: 2009-06-17
Anticipated expiration: 2023-03-24
Also published as: JP2004288542A

Description

【０００１】
【発明の属する技術分野】
本発明は円筒形固体電解質型燃料電池に関し、特にセル集合体と外部取り出し用電極の電気的接続に関する。
【０００２】
【従来の技術】
従来の筒状固体酸化物形燃料電池セル（以下燃料電池セルともいう）から構成される燃料電池発電システムの一般的な構成図を図５に示す。
燃料電池セル１は、有底筒状のセラミックチューブである。燃料電池セル１の断面は多層円筒状をしており、空気極、固体酸化物、燃料極等の各層が積層されている。燃料電池セル１の各層の肉厚は数μｍ〜２．５ｍｍであり、それぞれ必要な機能（導電性、通気性、固体酸化物、電気化学触媒性等）を有する酸化物を主成分とするセラミックス材で形成されている。この燃料電池セル１の内側に酸化剤ガス（空気や酸素リッチガス等、以下空気という）を流し、外側にＨ₂、ＣＯ、ＣＨ₄などの燃料ガスを流すと、この燃料電池セル１内でＯ₂-イオンが移動して電気化学的発電反応（以下発電反応という）が起こり、空気極と燃料極との間に電位差が生じて発電が行われる。１本の燃料電池セルの出力は限られているため、実際の燃料電池発電システムでは、燃料電池セル１を複数本集合させたセル集合体を構成して使用する。
それぞれの燃料電池セル１の内側には、空気を供給するための細長い空気導入管２が内挿されており、その下端は燃料電池セル１の底近くにまで達している。この空気導入管２の下端から、空気が燃料電池セル１の底に供給される。燃料電池セル１の底に供給された空気は、上述の発電反応に寄与しつつ燃料電池セル１の内側を上方に向かい排出される（排出ラインは図示しない）。燃料電池セル１の外側には、下方から燃料ガス（Ｈ₂、ＣＯ、ＣＨ₄等）が供給される。燃料ガスは、上述の発電反応に寄与しつつ燃料電池セル１の外側を上方に向かい、未反応の燃料ガスと、燃料電池セル１での発電反応生成物ガス（ＣＯ₂、Ｈ₂Ｏ等）は、排燃料ガスとして排出される（排出ラインは図示しない）。固体酸化物形燃料電池の発電反応部の温度は、約８００〜１０００℃であるため、排空気や排燃料ガスの保有する顕熱を熱交換器によって回収し、空気や燃料ガスの予熱に用いることもある。また、排空気と排燃料ガスを混合燃焼させ、その燃焼熱を熱交換器により回収して予熱を行うこともある。
【０００３】
次に、筒状固体酸化物型燃料電池における燃料電池セル１の接続構造について説明する。図６は、筒状固体酸化物型燃料電池の従来の接続状況を示す図である。この例では、燃料電池セル１をセル接続用導電部材３により３直列２並列に接続されたセル集合体６、セル集合体６と外部への電気取出しのための電極部材４を電気的に接続する電極接続用導電部材５で構成されており、燃料電池セル１は筒状面のほぼ全面で発電されるよう設計されているので、導電抵抗を低減させるためおよび発電電流の偏りを防ぐためセル接続用導電部材３、電極部材４および電極接続用導電部材５は燃料電池セル１の軸方向の多くの部分において接続される。一般に燃料電池セル１とセル接続用導電部材３の接続およびセル接続用導電部材３と電極接続用導電部材５の接続は、製造過程の焼成処理または運転中の昇温で拡散接合される。また、電極部材４と電極接続用導電部材５は溶接、ボルト固定などの機械的接合がなされている。
【０００４】
このような従来の燃料電池の構成では、電極接続用導電部材５を構成する金属材料の線膨張係数はニッケルの場合約１６μ／Ｋであり、セラミック系材料で作られたセル集合体６の線膨張係数１１μ／Ｋよりかなり大きいため、例えば運転温度１０００℃時でセル集合体６と電極接続用導電部材５との接続部分長さが５００ｍｍの場合、２．５ｍｍの歪が発生し、セル集合体６と電極接続用導電部材５との接続が損なわれる危険性があった。これに関しては、過去に電極接続用導電部材５を燃料電池セル１の軸方向に複数分割することで対策している。
（例えば、特許文献１参照）
【０００５】
【特許文献１】
特開２００１−２９７７８３号公報（第３〜４頁、第１図、第２図）
【０００６】
【発明が解決しようとする課題】
前述の電極接続用導電部材５を燃料電池セル１の軸方向に複数分割する対策では、電極接続用導電部材５が燃料電池セル１の熱膨張に追随するが、その結果電極接続用導電部材５と電極部材４の接続において上記と同様の歪が発生し、セル接続用導電部材３と電極接続用導電部材５の接続または電極部材４と電極接続用導電部材５の接続が損なわれる危険性がある。
【０００７】
本発明は、上記課題を解決し、セル接続用導電部材３と電極接続用導電部材５の接続または電極接続用導電部材５と電極部材４の接続において線膨張係数の違いに起因する歪から生じる応力を緩和することを目的とする。
【０００８】
【課題を解決するための手段】
第一の発明においては、電極接続用導電部材が、電極部材の長手方向に変形機能を有していることを特徴とする燃料電池システムを提供する。
これにより運転温度８００℃〜１０００℃時に、セル接続用導電部材３と電極接続用導電部材５の接続または電極接続用導電部材５と電極部材４の接続において線膨張係数の違いに起因する歪から生じる応力を緩和し、安定した発電性能で信頼性の高い燃料電池を提供できる。
【０００９】
電極接続用導電部材は電極部材に接続後、電極部材の周囲を半周以上巻きつけて設置することを特徴とする燃料電池システムを提供する。
これにより電極部材４の周囲に巻きついた部分の電極接続用導電部材５が螺旋状に変形することができ、比較的小さい力で電極部材４の軸方向に電極接続用導電部材５が変位することができる。よって、運転温度８００℃〜１０００℃時に、セル接続用導電部材３と電極接続用導電部材５の接続または電極接続用導電部材５と電極部材４の接続において線膨張係数の違いに起因する歪から生じる応力を緩和し、安定した発電性能で信頼性の高い燃料電池を提供できる。
【００１０】
電極接続用導電部材は少なくとも１箇所は略Ｓ字状に滑らかに折り曲げられて電極部材に接続することを特徴とする燃料電池システムを提供する。
これにより、電極接続用導電部材５を２箇所滑らかに折り曲げて略Ｓ字状したその２箇所の折り曲げ部分の間が斜めになるよう２箇所の折り曲げ部分が少量捩れ方向に変形することで、比較的小さい力で電極部材４の軸方向に電極接続用導電部材５が変位することができる。よって、運転温度８００℃〜１０００℃時に、セル接続用導電部材３と電極接続用導電部材５の接続または電極接続用導電部材５と電極部材４の接続において線膨張係数の違いに起因する歪から生じる応力を緩和し、安定した発電性能で信頼性の高い燃料電池を提供できる。
【００１１】
電極接続用導電部材は少なくとも１箇所はねじれ方向に変形後、電極部材に接続することを特徴とする燃料電池システムを提供する。
これにより、電極接続用導電部材５の面が水平となった部分で比較的小さい力で電極部材４の軸方向に電極接続用導電部材５が変位することができる。よって、運転温度８００℃〜１０００℃時に、セル接続用導電部材３と電極接続用導電部材５の接続または電極接続用導電部材５と電極部材４の接続において線膨張係数の違いに起因する歪から生じる応力を緩和し、安定した発電性能で信頼性の高い燃料電池を提供できる。
【００１２】
本発明においては、電極接続用導電部材は板状であって、電極部材とセル集合体との間に複数のスリット穴を設けていることを特徴とする燃料電池システムを提供する。これにより、電極接続用導電部材５は簡単な加工で製造可能であり、また分割される必要がなく一体品として取り扱えるので電極接続用導電部材と電極部材の接続が容易となる。
【００１３】
電極接続用導電部材は厚みが０．０５ｍｍ〜１．５ｍｍの範囲である部分を有することを特徴とする燃料電池システムを提供する。
これにより、第一から第四の発明において、電極接続用導電部材５の変形に必要な力が、セル接続用導電部材３と電極接続用導電部材５の接続または電極接続用導電部材５と電極部材４の接続部分を破損しない十分に小さい力になるよう抑えることができる。
【００１４】
電極接続用導電部材は材質がニッケルまたはニッケル含有合金であることを特徴とする燃料電池システムを提供する。
これにより、導電部材にニッケルまたはニッケル含有合金であることによって、高温雰囲気でも耐酸化性および導電性に優れ、また特にニッケルは高温で非常に柔らかい材料であるため、電極接続用導電部材５の変形に必要な力が比較的小さくできる。
【００１５】
電極接続用導電部材は燃料電池セルの軸方向に対して複数分割されていることを特徴とする燃料電池システムを提供する。
これにより、従来構造で考慮されたセル接続用導電部材３と電極接続用導電部材５間の応力緩和だけでなく、分割部分のそれぞれの位置に応じた変形量を担わせることでトータルとして変形に必要な力を最小限にすることができる。
【００１６】
以下に図面を参照して本発明をより具体的に説明する。
図１は本発明の参考例を示す略示する図である。燃料電池セル１がセル接続用導電部材３により３直列２並列に接続されセル集合体６を構成し、セル集合体６が電極接続用導電部材５と拡散接合で接続され、電極接続用導電部材５が電極部材４に接続されることで電極部材４を介して外部に電力を取り出すことができる。図示していないがセル集合体６に電極接続用導電部材５が接続されている面の反対面またはセル集合体６が複数直列に接続された最終端面にも、同様に電極接続用導電部材５と拡散接合で接続され、電極接続用導電部材５が電極部材４に接続されて電気が取り出せる。このようにして発生電力の正極、負極が設けられている。
ここでは、電極接続用導電部材５の端面を電極部材４に溶接などの固定手段により接続後、電極部材４の周りを２周と３／４周巻きつけてセル集合体６に接続されている。例えば、３枚の電極接続用導電部材５の上端下端の位置寸法差が５００ｍｍで電極部材４の下端が熱膨張の変位基点である場合、電極部材４に接続された電極接続用導電部材５の上端は、運転温度１０００℃において８ｍｍ上方に変位する。一方セル集合体６に接続された電極接続用導電部材５の上端は、分割によりほぼセル集合体６の熱膨張に従うと仮定すると５．５ｍｍ上方に変位する。よって電極接続用導電部材５の電極部材４側とセル集合体６側では２．５ｍｍの変位差が生じる。この時発生する歪は、電極部材４の周りに巻きつけられた部分の電極接続用導電部材５が螺旋状に変形することで前記変位差を吸収することができる。この螺旋状変形では螺旋面の全面において軽微な捩れ変形を連続させるため小さな応力で大きな変位を実現できる。よって、半周程度の巻き数でも前記機能は発揮するが導電抵抗が許される範囲内で巻き数を増加させた方が、電極接続用導電部材５内および電極部材４またはセル接続用導電部材３との接続部に発生する応力を小さくすることができる。また、電極部材４の周りを巻きつける際には、各周間に若干のクリアランスを設けることが望ましい。
【００１７】
図２は本発明の参考例を示す略示する図である。ここでは電極接続用導電部材５を２箇所反対向きに１８０°ずつ折り滑らかに曲げてＳ字状にし、片端を電極部材４、もう片端をセル接続用導電部材３に接続している。これにより、２箇所の折り曲げ部分の間が斜めになるよう２箇所の折り曲げ部分が少量捩れ方向に変形することで、比較的小さい力で電極部材４の軸方向に電極接続用導電部材５が変位することができる。図中では折り曲げ部分は１８０°折り返されているが、３０°などの浅い角度であってもよい。
【００１８】
図３は本発明の参考例を示す略示する図である。ここでは、電極接続用導電部材５をねじれ方向に９０°変形後、電極部材４に接続している。これにより、電極接続用導電部材５の面が水平となった部分で比較的小さい力で電極部材４の軸方向に電極接続用導電部材５が変位することができる。図中は捩れ角度９０°の例を表しているが、電極接続用導電部材５内および電極部材４またはセル接続用導電部材３との接続部に発生する応力が許容できる範囲内で捩れ角度は任意に選定できる。
【００１９】
これら図１〜３の例では、電極接続用導電部材５の変形抵抗を小さくするため、部材の厚みを薄くすることが有利である。ただし電極接続用導電部材５のトータル断面積が小さくなると導電抵抗が増大するため、厚み０．０５ｍｍ〜１．５ｍｍの範囲で選定することが望ましい。
また、これら図１〜３の例では、電極接続用導電部材５を電極部材４の軸方向に複数分割することが望ましい。こうすることにより電極接続用導電部材５のセル接続用導電部材３との接続部分における熱膨張による歪量が分割されることにより１枚当りの歪量が小さくなるため、接続部分に発生する応力を緩和することができる。また、電極接続用導電部材５と電極部材４との高さ方向の変位量差を各箇所ごとに必要な変位量に分割させることで全体として電極接続用導電部材５内および電極部材４またはセル接続用導電部材３との接続部に発生する応力を最小限にすることができる。
また、前述の例のように電極部材４の下端が熱膨張の変位基点であるような場合が想定される。このように電極接続用導電部材５の電極部材４側変位とセル接続用導電部材３側変位が高さ方向で変わらない箇所付近においては、当然ながら本発明を適用する必要はなく従来通りの接続でよい。
【００２０】
図４は本発明の一実施例を示す略示する図である。高さ方向に電極接続用導電部材５を変形する場合、同じ断面積であれば高さを低くし幅を大きくすることで断面係数を小さくすることが有利である。ここでは、電極接続用導電部材５に複数のスリット穴を設けることで断面係数を小さくしている。さらに前述の例と同様、電極部材の巻き付けおよびまたはＳ字状の変更と併用することで変形抵抗を低減することは可能である。実際には電極接続用導電部材５の厚みは１ｍｍ〜４ｍｍ程度、スリット高さを数ｍｍ程度の中から導電抵抗と変形抵抗がそれぞれ許容範囲に収まるよう設計される。スリット穴は一般にパンチングなどの機械加工による量産化が容易で安価に加工が可能である。また電極接続用導電部材５を電極部材４に接続する際、電極接続用導電部材５が一体型であるので組立工数を削減することができる。
【００２１】
本発明の特定の実施例を例示の目的で説明したが、頭書の特許請求の範囲に定義された本発明から逸脱することなく、種々の変形例及び設計変更が可能である。
【図面の簡単な説明】
【図１】筒状固体酸化物形燃料電池の参考例を略示する図である。
【図２】筒状固体酸化物形燃料電池の参考例を略示する図である。
【図３】筒状固体酸化物形燃料電池の参考例を略示する図である。
【図４】本発明の筒状固体酸化物形燃料電池の実施例を略示する図である。
【図５】従来の筒状固体酸化物形燃料電池の断面構造例を模式的に示す図である。
【図６】従来の筒状固体酸化物形燃料電池を略示する図である。
【符号の説明】
１燃料電池セル
２空気導入管
３セル接続用導電部材
４電極部材
５電極接続用導電部材
６セル集合体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cylindrical solid oxide fuel cell, and more particularly to electrical connection between a cell assembly and an external extraction electrode.
[0002]
[Prior art]
FIG. 5 shows a general configuration diagram of a fuel cell power generation system including conventional cylindrical solid oxide fuel cells (hereinafter also referred to as fuel cells).
The fuel cell 1 is a bottomed cylindrical ceramic tube. The cross section of the fuel cell 1 has a multilayer cylindrical shape, and layers such as an air electrode, a solid oxide, and a fuel electrode are laminated. The thickness of each layer of the fuel battery cell 1 is several μm to 2.5 mm, and ceramics whose main component is an oxide having necessary functions (conductivity, air permeability, solid oxide, electrochemical catalytic property, etc.). It is made of material. When an oxidant gas (air, oxygen-rich gas, etc., hereinafter referred to as air) is allowed to flow inside the fuel battery cell 1 and a fuel gas such as H ₂ , CO, CH _4, etc. is allowed to flow outside, ₂ -The ions move to cause an electrochemical power generation reaction (hereinafter referred to as a power generation reaction), and a potential difference is generated between the air electrode and the fuel electrode to generate power. Since the output of one fuel cell is limited, an actual fuel cell power generation system configures and uses a cell assembly in which a plurality of fuel cells 1 are assembled.
Inside each fuel cell 1, an elongated air introduction pipe 2 for supplying air is inserted, and the lower end thereof reaches the vicinity of the bottom of the fuel cell 1. Air is supplied to the bottom of the fuel cell 1 from the lower end of the air introduction pipe 2. The air supplied to the bottom of the fuel cell 1 is exhausted upward inside the fuel cell 1 while contributing to the above-described power generation reaction (a discharge line is not shown). Fuel gas (H ₂ , CO, CH _4, etc.) is supplied to the outside of the fuel cell 1 from below. The fuel gas contributes to the above-described power generation reaction, and moves upward outside the fuel cell 1 to generate an unreacted fuel gas and a power generation reaction product gas (CO ₂ , H ₂ O, etc.) in the fuel cell 1. Is discharged as exhaust fuel gas (discharge line not shown). Since the temperature of the power generation reaction part of the solid oxide fuel cell is about 800 to 1000 ° C., the sensible heat possessed by the exhaust air and the exhaust fuel gas is recovered by a heat exchanger and used for preheating the air and the fuel gas. Sometimes. In addition, exhaust air and exhaust fuel gas may be mixed and burned, and the combustion heat may be recovered by a heat exchanger to be preheated.
[0003]
Next, the connection structure of the fuel cell 1 in the cylindrical solid oxide fuel cell will be described. FIG. 6 is a diagram showing a conventional connection state of a cylindrical solid oxide fuel cell. In this example, the cell assembly 6 in which the fuel cells 1 are connected in series 3 in parallel by the cell connection conductive member 3, and the electrode assembly 4 for electrical extraction to the outside are electrically connected. The fuel cell 1 is designed to generate power over almost the entire surface of the cylindrical surface, so that the cell can be used to reduce the conductive resistance and prevent the bias of the generated current. The connecting conductive member 3, the electrode member 4, and the electrode connecting conductive member 5 are connected at many portions in the axial direction of the fuel cell 1. In general, the connection between the fuel cell 1 and the cell connecting conductive member 3 and the connection between the cell connecting conductive member 3 and the electrode connecting conductive member 5 are diffusion-bonded by a firing process in the manufacturing process or a temperature rise during operation. Further, the electrode member 4 and the electrode connecting conductive member 5 are mechanically joined such as welding and bolt fixing.
[0004]
In such a conventional fuel cell configuration, the linear expansion coefficient of the metal material composing the electrode connecting conductive member 5 is about 16 μ / K in the case of nickel, and the wire of the cell assembly 6 made of a ceramic material. Since the expansion coefficient is considerably larger than 11 μ / K, for example, when the connection portion length between the cell assembly 6 and the electrode connecting conductive member 5 is 500 mm at an operating temperature of 1000 ° C., a strain of 2.5 mm occurs, and the cell assembly There was a risk that the connection between the body 6 and the conductive member 5 for electrode connection may be impaired. Regarding this, measures are taken in the past by dividing the electrode connecting conductive member 5 into a plurality of parts in the axial direction of the fuel cell 1.
(For example, see Patent Document 1)
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-297883 (pages 3 to 4, FIGS. 1 and 2)
[0006]
[Problems to be solved by the invention]
In the measure for dividing the electrode connecting conductive member 5 in the axial direction of the fuel cell 1, the electrode connecting conductive member 5 follows the thermal expansion of the fuel cell 1, and as a result, the electrode connecting conductive member 5. In the connection between the electrode member 4 and the electrode member 4, there is a risk that the same distortion as described above occurs, and the connection between the cell connecting conductive member 3 and the electrode connecting conductive member 5 or the connection between the electrode member 4 and the electrode connecting conductive member 5 is impaired. is there.
[0007]
The present invention solves the above-mentioned problems and arises from distortion caused by the difference in linear expansion coefficient in connection between the cell connection conductive member 3 and the electrode connection conductive member 5 or connection between the electrode connection conductive member 5 and the electrode member 4. The purpose is to relieve stress.
[0008]
[Means for Solving the Problems]
In 1st invention, the electrically-conductive member for electrode connection has a deformation function in the longitudinal direction of an electrode member, The fuel cell system characterized by the above-mentioned is provided.
Thus, when the operating temperature is 800 ° C. to 1000 ° C., distortion caused by the difference in linear expansion coefficient in connection between the cell connecting conductive member 3 and the electrode connecting conductive member 5 or in the connection between the electrode connecting conductive member 5 and the electrode member 4. It is possible to provide a highly reliable fuel cell with reduced power generation and stable power generation performance.
[0009]
After the electrode connecting conductive member is connected to the electrode member, a fuel cell system is provided in which the periphery of the electrode member is wound around a half or more.
Accordingly, the electrode connecting conductive member 5 wound around the electrode member 4 can be helically deformed, and the electrode connecting conductive member 5 is displaced in the axial direction of the electrode member 4 with a relatively small force. be able to. Therefore, when the operating temperature is 800 ° C. to 1000 ° C., the distortion caused by the difference in the linear expansion coefficient in the connection between the cell connecting conductive member 3 and the electrode connecting conductive member 5 or in the connection between the electrode connecting conductive member 5 and the electrode member 4. It is possible to provide a highly reliable fuel cell with reduced power generation and stable power generation performance.
[0010]
A fuel cell system is provided in which at least one conductive member for electrode connection is smoothly bent into a substantially S shape and connected to the electrode member.
By this, the two bent portions are bent in a small amount in a twisting direction so that the portion between the two bent portions that are smoothly S-shaped by smoothly bending the two electrode connecting conductive members 5 is deformed in the twist direction. The electrode connecting conductive member 5 can be displaced in the axial direction of the electrode member 4 with a relatively small force. Therefore, when the operating temperature is 800 ° C. to 1000 ° C., the distortion caused by the difference in the linear expansion coefficient in the connection between the cell connecting conductive member 3 and the electrode connecting conductive member 5 or in the connection between the electrode connecting conductive member 5 and the electrode member 4. It is possible to provide a highly reliable fuel cell with reduced power generation and stable power generation performance.
[0011]
Provided is a fuel cell system in which at least one conductive member for electrode connection is deformed in a twisting direction and then connected to the electrode member.
Accordingly, the electrode connecting conductive member 5 can be displaced in the axial direction of the electrode member 4 with a relatively small force at a portion where the surface of the electrode connecting conductive member 5 is horizontal. Therefore, when the operating temperature is 800 ° C. to 1000 ° C., the distortion caused by the difference in the linear expansion coefficient in the connection between the cell connecting conductive member 3 and the electrode connecting conductive member 5 or in the connection between the electrode connecting conductive member 5 and the electrode member 4. It is possible to provide a highly reliable fuel cell with reduced power generation and stable power generation performance.
[0012]
According to the present invention , there is provided a fuel cell system characterized in that the electrode connecting conductive member is plate-shaped, and a plurality of slit holes are provided between the electrode member and the cell assembly. As a result, the electrode connecting conductive member 5 can be manufactured by a simple process, and can be handled as an integral part without being divided, so that the electrode connecting conductive member and the electrode member can be easily connected.
[0013]
The conductive member for electrode connection has a portion having a thickness in the range of 0.05 mm to 1.5 mm, and provides a fuel cell system.
Accordingly, in the first to fourth aspects of the invention, the force necessary for the deformation of the electrode connecting conductive member 5 is the connection between the cell connecting conductive member 3 and the electrode connecting conductive member 5 or the electrode connecting conductive member 5 and the electrode. It can be suppressed to a sufficiently small force that does not damage the connecting portion of the member 4.
[0014]
The electrode connecting conductive member is made of nickel or a nickel-containing alloy, and a fuel cell system is provided.
Accordingly, since the conductive member is nickel or a nickel-containing alloy, it is excellent in oxidation resistance and conductivity even in a high temperature atmosphere. In particular, since nickel is a very soft material at a high temperature, the deformation of the electrode connecting conductive member 5 The required force can be relatively small.
[0015]
The electrode connecting conductive member is divided into a plurality of parts in the axial direction of the fuel cell, and a fuel cell system is provided.
As a result, not only the stress relaxation between the cell connection conductive member 3 and the electrode connection conductive member 5 considered in the conventional structure but also the deformation amount according to the respective positions of the divided portions can be deformed as a total. The required force can be minimized.
[0016]
Hereinafter, the present invention will be described more specifically with reference to the drawings.
FIG. 1 is a schematic diagram showing a reference example of the present invention. The fuel cell 1 is connected in series 3 in parallel by a cell connecting conductive member 3 to form a cell assembly 6, and the cell assembly 6 is connected to the electrode connecting conductive member 5 by diffusion bonding, and the electrode connecting conductive member By connecting 5 to the electrode member 4, electric power can be taken out through the electrode member 4. Although not shown, the electrode connecting conductive member 5 is similarly applied to the surface opposite to the surface where the electrode connecting conductive member 5 is connected to the cell assembly 6 or the final end surface where a plurality of cell assemblies 6 are connected in series. And the electrode connecting conductive member 5 is connected to the electrode member 4 so that electricity can be taken out. In this way, a positive electrode and a negative electrode for the generated power are provided.
Here, after the end surface of the electrode connecting conductive member 5 is connected to the electrode member 4 by fixing means such as welding, the electrode member 4 is wound around the electrode member 4 by 2 turns and 3/4 turn and connected to the cell assembly 6. . For example, when the positional dimensional difference between the upper and lower ends of the three electrode connecting conductive members 5 is 500 mm and the lower end of the electrode member 4 is a displacement base point of thermal expansion, the electrode connecting conductive member 5 connected to the electrode member 4 The upper end is displaced 8 mm upward at an operating temperature of 1000 ° C. On the other hand, it is assumed that the upper end of the electrode connecting conductive member 5 connected to the cell assembly 6 substantially follows the thermal expansion of the cell assembly 6 due to the division. Displace 5mm upward. Therefore, a displacement difference of 2.5 mm occurs between the electrode member 4 side and the cell assembly 6 side of the electrode connecting conductive member 5. The distortion generated at this time can absorb the displacement difference as the electrode connecting conductive member 5 wound around the electrode member 4 is deformed in a spiral shape. In this helical deformation, since a slight torsional deformation is continued over the entire surface of the spiral surface, a large displacement can be realized with a small stress. Therefore, the above-mentioned function is exhibited even when the number of turns is about half a circle, but increasing the number of turns within the range in which the conductive resistance is allowed increases the number of turns in the electrode connecting conductive member 5 and the electrode member 4 or the cell connecting conductive member 3. The stress generated in the connecting portion can be reduced. Moreover, when winding around the electrode member 4, it is desirable to provide a slight clearance between each circumference.
[0017]
FIG. 2 is a schematic diagram showing a reference example of the present invention. Here, the electrode connection conductive member 5 is bent 180 degrees in two opposite directions and bent smoothly into an S shape, and one end is connected to the electrode member 4 and the other end is connected to the cell connection conductive member 3. As a result, the two bent portions are deformed in a small amount in the twist direction so that the two bent portions are inclined, so that the electrode connecting conductive member 5 is displaced in the axial direction of the electrode member 4 with a relatively small force. can do. In the drawing, the bent portion is folded 180 °, but may be a shallow angle such as 30 °.
[0018]
FIG. 3 is a schematic diagram showing a reference example of the present invention. Here, the electrode connecting conductive member 5 is deformed by 90 ° in the twisting direction and then connected to the electrode member 4. Accordingly, the electrode connecting conductive member 5 can be displaced in the axial direction of the electrode member 4 with a relatively small force at a portion where the surface of the electrode connecting conductive member 5 is horizontal. In the drawing, an example of a twist angle of 90 ° is shown. However, the twist angle is within a range in which the stress generated in the electrode connecting conductive member 5 and the connecting portion with the electrode member 4 or the cell connecting conductive member 3 is allowable. Can be selected arbitrarily.
[0019]
In these examples of FIGS. 1 to 3, it is advantageous to reduce the thickness of the member in order to reduce the deformation resistance of the electrode connecting conductive member 5. However, when the total cross-sectional area of the electrode connecting conductive member 5 is reduced, the conductive resistance is increased. Therefore, it is desirable to select the thickness within a range of 0.05 mm to 1.5 mm.
1 to 3, it is desirable to divide the electrode connecting conductive member 5 into a plurality of parts in the axial direction of the electrode member 4. By doing so, the strain amount due to thermal expansion at the connection portion between the electrode connecting conductive member 5 and the cell connecting conductive member 3 is divided, so that the strain amount per one sheet is reduced, so that the stress generated at the connecting portion is reduced. Can be relaxed. In addition, by dividing the displacement amount difference in the height direction between the electrode connecting conductive member 5 and the electrode member 4 into necessary displacement amounts for each portion, the electrode connecting conductive member 5 and the electrode member 4 or the cell as a whole are divided. The stress generated at the connection portion with the connecting conductive member 3 can be minimized.
Moreover, the case where the lower end of the electrode member 4 is a displacement base point of thermal expansion like the above-mentioned example is assumed. Thus, in the vicinity of the portion where the displacement of the electrode connecting conductive member 5 on the electrode member 4 side and the displacement of the cell connecting conductive member 3 side do not change in the height direction, it is of course unnecessary to apply the present invention. It's okay.
[0020]
FIG. 4 is a schematic diagram showing an embodiment of the present invention . When the electrode connecting conductive member 5 is deformed in the height direction, it is advantageous to reduce the section modulus by decreasing the height and increasing the width if the cross-sectional area is the same. Here, the section modulus is reduced by providing a plurality of slit holes in the electrode connecting conductive member 5. Further, similarly to the above-described example, it is possible to reduce the deformation resistance by using it together with the winding of the electrode member and / or the change of the S shape. Actually, the conductive member for electrode connection 5 is designed to have a thickness of about 1 mm to 4 mm and a slit height of about several mm so that the conductive resistance and the deformation resistance are within the allowable ranges. Slit holes are generally easy to mass-produce by machining such as punching and can be processed at low cost. Further, when the electrode connecting conductive member 5 is connected to the electrode member 4, the electrode connecting conductive member 5 is integrated, so that the number of assembling steps can be reduced.
[0021]
While particular embodiments of the present invention have been described for purposes of illustration, various modifications and changes in design may be made without departing from the invention as defined in the appended claims.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a reference example of a cylindrical solid oxide fuel cell.
FIG. 2 is a diagram schematically showing a reference example of a cylindrical solid oxide fuel cell.
FIG. 3 is a diagram schematically showing a reference example of a cylindrical solid oxide fuel cell.
FIG. 4 is a diagram schematically showing an example of a cylindrical solid oxide fuel cell according to the present invention.
FIG. 5 is a diagram schematically showing an example of a cross-sectional structure of a conventional cylindrical solid oxide fuel cell.
FIG. 6 is a diagram schematically showing a conventional cylindrical solid oxide fuel cell.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Air introduction pipe 3 Conductive member 4 for cell connection Electrode member 5 Conductive member 6 for electrode connection Cell assembly

Claims

A cell assembly in which a plurality of cylindrical fuel cells each having an anode and a cathode on both sides of an electrolyte are connected by a cell connecting conductive member;
An electrode member disposed parallel to the axial direction of the cylindrical fuel cell;
An electrode connecting conductive member for electrically connecting the cylindrical fuel cell and the electrode member;
A fuel cell system comprising:
The conductive member for electrode connection has a plate shape and has a function of deforming in the longitudinal direction of the cylindrical fuel cell by providing a plurality of slit holes between the electrode member and the cell assembly. A fuel cell system characterized by comprising: