JP2014017244A - Stack structure of fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability at the joint of a connection member and a cell, in the stack structure of a fuel cell where the connection member for electrically connecting the adjoining cells is interposed therebetween and joined thereto.SOLUTION: A connection member 300 interposed between adjoining cells and joined thereto is constituted of "a pair of stationary portions 310, 310 being joined, respectively, to adjoining cells", and "a coupling portion 320 for coupling a pair of side ends 311, 311 extending in the z-axis direction at the ends of the pair of stationary portions 310, 310 on the x-axis negative direction side". The coupling portion 320 includes a pair of parts 321, 321 extending, respectively, from the end on the z-axis positive direction side in the pair of side ends 311, 311 toward the x-axis negative direction side, a pair of parts 322, 322 extending, respectively, from the tip side of the pair of parts 321, 321 toward the z-axis negative direction side, and a part 323 for coupling the tip sides of the pair of parts 322, 322.

Description

  The present invention relates to a fuel cell stack structure.

  Conventionally, a plurality of cells each having “a power generation element portion including an inner electrode, a solid electrolyte, and an outer electrode”, and the plurality of cells are arranged in a stack at intervals. A solid oxide type comprising: a supporting member for supporting; and a connecting member that is provided between the adjacent cells and electrically connects between the power generating element portions of the adjacent cells. A stack structure of a fuel cell (hereinafter referred to as “SOFC”) is known (see, for example, Patent Document 1).

JP 2010-231920 A

  FIG. 22 schematically shows an example of a stack structure of SOFC cells described in the above-mentioned document, and FIG. 23 schematically shows a “connecting member for electrically connecting adjacent SOFC cells” shown in FIG. Shown in As can be understood from FIGS. 22 and 23, the connection member used in the stack structure described in the above document includes a pair of fixing portions and a coupling portion. The pair of fixing portions face each other in parallel in the y-axis direction with a space therebetween. Each of the pair of fixed portions is fixed to a corresponding cell among adjacent SOFC cells and is electrically connected to the power generation element portion of the corresponding cell. The connecting portion connects “a pair of side end portions” on the x-axis negative direction side of the pair of fixed portions. The “pair of side end portions” face each other in parallel in the y-axis direction with a space therebetween. Each of the “pair of side end portions” extends in the z-axis direction.

  By the way, in the stack structure as described above, relative displacement may inevitably occur between adjacent cells during SOFC operation or the like. This is because, in the connection member shown in FIG. 23, the relative rotational displacement seen from the x-axis direction (see FIG. 9 described later) and the relative rotational displacement seen from the y-axis direction (see FIG. 10 described later) between the pair of fixed portions. As well as relative rotational displacements (see FIG. 8) as seen in the z-axis direction.

  In the connection member shown in FIG. 23, the connecting portion connects the “pair of side end portions” over the entire region in the z-axis direction of the “pair of side end portions”. Due to this, while the rigidity against “elastic deformation with relative rotational displacement seen from the z-axis direction between the pair of fixed portions shown in FIG. 23” is low, The rigidity with respect to “elastic deformation accompanied by relative rotational displacement seen from the axial direction as well as the y-axis direction” is high. Therefore, in the case where a relative rotational displacement as seen from the x-axis direction or the y-axis direction occurs between adjacent cells, at the junction between the “pair of fixed portions of the connection member” and the “cell (power generation element portion)” A relatively large stress is likely to occur. As a result, there is a problem that the reliability of the joint portion is low.

  The present invention provides a stack structure of a fuel cell having the basic configuration as described above, which has high reliability at the joint between the “pair of fixing portions of the connecting member” and the “cell”. With the goal.

  The fuel cell stack structure according to the present invention has the above-described basic characteristics. The feature of this stack structure is that the connecting portion of the connection member is only at one end in the second direction (z-axis direction) in the “pair of side ends” or in the “pair of side ends”. The “pair of side end portions” is connected only at the center portion excluding both end portions in the second direction (z-axis direction).

  According to this, compared with the configuration shown in FIG. 23 (the configuration in which the coupling portion couples the “pair of side end portions” over the entire z-axis direction in the “pair of side end portions”), The rigidity with respect to “elastic deformation accompanied by relative rotational displacement seen from the x-axis direction and the y-axis direction” is low. In addition, similarly to the configuration shown in FIG. 23, the rigidity against “elastic deformation with relative rotational displacement seen from the z-axis direction between the pair of fixed portions” is also low. That is, the rigidity with respect to all of “elastic deformation accompanied by respective relative rotational displacements seen from the three axis directions of the x-axis, y-axis, and z-axis between the pair of fixed portions” is low. Therefore, this connecting member has a configuration with low rigidity against “elastic deformation that causes a three-dimensional relative displacement between the pair of fixed portions”. As a result, even if a three-dimensional relative displacement occurs between adjacent cells, as compared with the configuration shown in FIG. 23, “a pair of fixing portions of the connection member” and “a cell (power generation element portion)” The stress acting on the joint is reduced, and the reliability at the joint is increased.

  Specifically, the connecting portion of the connection member is connected to one side in the first direction (x-axis direction) from one end in the second direction (z-axis direction) in the pair of side ends. From the pair of first extending portions respectively extending toward the other side in the second direction (z-axis direction) and the pair of tip portions on the tip side of the pair of first extending portions, the first and second A second extending portion that extends in a third direction (y-axis direction) different from the direction and connects the tip portions of the pair of first extending portions.

  In this case, the first extending portion is directed from one end portion of the second direction (z-axis direction) in the pair of side end portions toward one side of the first direction (x-axis direction). A pair of first portions extending respectively, and a pair of second portions extending respectively from the pair of tip portions on the tip side of the pair of first portions toward the other side of the second direction (z-axis direction). The second extending portion may be configured to connect a pair of tip portions on the tip side of the pair of second portions. The pair of fixing portions preferably have a pair of flat plate-like shapes facing each other at an interval, and the first, second, and third directions are preferably perpendicular to each other. The connecting member is formed by bending a thin plate-like member, and the width of the thin plate-like member in a direction orthogonal to the extending direction of the portion on the main surface of the portion corresponding to the connecting portion. However, it is preferable that the thickness of the thin plate member is larger.

It is a perspective view which shows one cell used for the stack structure of the fuel cell which concerns on embodiment of this invention. 1 is an overall perspective view of a stack structure of a fuel cell according to an embodiment of the present invention. FIG. 3 is a perspective view of the entire fuel gas manifold shown in FIG. 2. FIG. 3 is an enlarged view of the stack structure when the stack structure shown in FIG. 2 is viewed from above. It is the figure which showed a mode that fuel gas and air were supplied and discharged | emitted with respect to the stack structure shown in FIG. It is a perspective view of the whole connection member shown in FIG. It is an expanded view of the connection member shown in FIG. It is the figure which showed the mode of the elastic deformation of the connection member in case the relative rotational displacement seen from the z-axis direction generate | occur | produced between adjacent cells. It is the figure which showed the mode of the elastic deformation of the connection member in case the relative rotational displacement seen from the x-axis direction generate | occur | produced between adjacent cells. It is the figure which showed the mode of the elastic deformation of the connection member in case the relative rotational displacement seen from the y-axis direction generate | occur | produced between adjacent cells. It is a perspective view corresponding to FIG. 6 about the connection member which concerns on the modification of embodiment of this invention. FIG. 12 is a development view corresponding to FIG. 7 for the connection member shown in FIG. 11. It is a perspective view corresponding to FIG. 6 about the connection member which concerns on the other modification of embodiment of this invention. It is an expanded view corresponding to FIG. 7 about the connection member shown in FIG. It is a perspective view corresponding to FIG. 6 about the connection member which concerns on the other modification of embodiment of this invention. It is an expanded view corresponding to FIG. 7 about the connection member shown in FIG. It is a perspective view corresponding to FIG. 6 about the connection member which concerns on the other modification of embodiment of this invention. It is an expanded view corresponding to FIG. 7 about the connection member shown in FIG. FIG. 9 is a view corresponding to FIG. 8 illustrating a joined body in which front and back surfaces of one cell are electrically connected by a connection member. FIG. 10 is a view corresponding to FIG. 9 showing a joined body in which the front and back sides of one cell are electrically connected by a connecting member. FIG. 11 is a view corresponding to FIG. 10 illustrating a joined body in which front and back surfaces of one cell are electrically connected by a connection member. It is a figure corresponding to FIG. 4 about the stack structure of the conventional fuel cell. It is a perspective view of the whole connection member shown in FIG.

(Example of cell configuration used for stack structure)
First, a cell 100 used in a stack structure of a solid oxide fuel cell (SOFC) according to an embodiment of the present invention will be described. As shown in FIG. 1, in a cell 100, one main surface of a flat porous conductive support 11 is composed of a porous fuel electrode 12, a dense solid electrolyte 13, and porous conductive ceramics. Air electrodes 14 are sequentially stacked. Further, an intermediate film 15, an interconnector 16 made of a lanthanum-chromium oxide material, and a current collecting film 17 made of a P-type semiconductor material are sequentially formed on the main surface of the conductive support 11 opposite to the air electrode 14. Has been.

  The cell 100 has a flat plate shape having a first longitudinal direction (z-axis direction), the length L1 (length in the first longitudinal direction) of the cell 100 is 50 to 500 mm, and the width L2 is 10 to 100 mm. The thickness L3 is 1 to 5 mm (L1> L2). The shape of the side surface of one end portion in the first longitudinal direction (z-axis direction) of the cell 100 (length L2, oval shape of width L3, L2> L3) has the second longitudinal direction (x-axis direction).

  In addition, a plurality of gas flow paths (through holes) 18 parallel to each other are formed in the conductive support 11 at intervals in the width direction (x direction) along the longitudinal direction (z axis direction). Yes. The cross-sectional shape of each gas channel 18 is a circle having a diameter of 0.5 to 3 mm. The space | interval (pitch) in the width direction of the adjacent gas flow paths 18 and 18 is 1-5 mm. In addition, the cross-sectional shape of each gas flow path 18 may be an ellipse, a long hole, a quadrangle having arcs at four corners, or the like.

  The cell 100 includes side end portions B and B provided on both sides in the width direction (direction perpendicular to the longitudinal direction) and a pair of flat portions A and A connecting the side end portions B and B, respectively. ing. The pair of flat portions A and A are flat and substantially parallel. On one of the flat portions A and A, the fuel electrode 12, the solid electrolyte 13, and the air electrode 14 are formed in this order on one main surface of the conductive support 11, and on the other of the flat portions A and A, On the other main surface of the conductive support 11, an intermediate film 15, an interconnector 16, and a current collecting film 17 are formed in this order.

  The width of the conductive support 11 is preferably 10 to 100 mm, and the thickness is preferably 1 to 5 mm. The aspect ratio (width / thickness) of the conductive support 11 is 5 to 100. The shape of the conductive support 11 is expressed as “thin plate shape”, but depending on the combination of the dimension in the width direction and the dimension in the thickness direction, it may be referred to as “ellipsoidal column shape” or “flat shape”. Can be expressed.

  The conductive support 11 is composed mainly of a rare earth element oxide composed of one or more selected from Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, Sm and Pr and Ni and / or NiO. It is desirable to be composed of the material In addition to Ni, Fe, Cu, or the like may be included.

The conductive support 11 can also be described as including “NiO (nickel oxide) or Ni (nickel)” and “insulating ceramics”. Insulating ceramics include CSZ (calcia stabilized zirconia), YSZ (8YSZ) (yttria stabilized zirconia), Y ₂ O ₃ (yttria), MgO (magnesium oxide), or “MgAl ₂ O ₄ (magnesia alumina spinel). ) And MgO (magnesium oxide) "or the like. The conductivity of the conductive support 11 is 10 to 2000 S / cm at 800 ° C. The porosity of the conductive support 11 is 20 to 60%.

The intermediate film 15 formed between the conductive support 11 and the interconnector 16 is made of a material mainly containing ZrO ₂ containing Ni and / or NiO and a rare earth element, or a rare earth oxide (for example, Y ₂ O ₃ ). The Ni conversion amount of the Ni compound in the intermediate film 15 is preferably 35 to 80% by volume, and more preferably 50 to 70% by volume in the total amount. When the Ni conversion amount is 35% by volume or more, the conductive path by Ni is increased, and the conductivity of the intermediate film 15 is improved. As a result, the voltage drop caused by the intermediate film 15 is reduced. Moreover, when the Ni conversion amount is 80% by volume or less, the difference in thermal expansion coefficient between the conductive support 11 and the interconnector 16 can be reduced, and the occurrence of cracks at the interface between the two can be suppressed.

  Further, from the viewpoint of reducing the voltage drop, the thickness of the intermediate film 15 is preferably 20 μm or less, and more preferably 10 μm or less.

The thermal expansion coefficient of the middle rare earth element or heavy rare earth element oxide is smaller than that of “ZrO ₂ containing Y ₂ O ₃ ” in the solid electrolyte 13. Therefore, the thermal expansion coefficient of the conductive support 11 as a cermet material with Ni can be made closer to the thermal expansion coefficient of the solid electrolyte 13. As a result, cracks in the solid electrolyte 13 and separation of the solid electrolyte 13 from the fuel electrode 12 can be suppressed. Furthermore, by using a heavy rare earth element oxide having a small thermal expansion coefficient, Ni in the conductive support 11 can be increased, and the electrical conductivity of the conductive support 11 can be increased. From this viewpoint, it is desirable to use heavy rare earth element oxides.

  If the sum of the thermal expansion coefficients of the rare earth element oxide is less than the thermal expansion coefficient of the solid electrolyte 13, the light rare earth elements La, Ce, Pr, and Nd oxides are added to the medium rare earth element and heavy rare earth element. There is no problem even if it is contained.

  Moreover, the raw material cost can be significantly reduced by using a complex rare earth element oxide containing a plurality of inexpensive rare earth elements in the course of purification. Also in this case, it is desirable that the thermal expansion coefficient of the complex rare earth element oxide is less than the thermal expansion coefficient of the solid electrolyte 13.

  Further, it is desirable to provide a current collector film 17 made of a P-type semiconductor, for example, a transition metal perovskite oxide, on the surface of the interconnector 16. When a current collecting member made of metal is disposed directly on the surface of the interconnector 16, the potential drop increases due to non-ohmic contact. In order to secure ohmic contact and reduce the potential drop, it is necessary to connect the current collector film 17 made of a P-type semiconductor to the interconnector 16. As the P-type semiconductor, it is desirable to use a transition metal perovskite oxide. As the transition metal perovskite oxide, it is desirable to use at least one of a lanthanum-manganese oxide, a lanthanum-iron oxide, a lanthanum-cobalt oxide, or a composite oxide thereof.

The fuel electrode 12 provided on the main surface of the conductive support 11 is composed of Ni and ZrO _{2 in} which a rare earth element is dissolved. The thickness of the fuel electrode 12 is desirably 1 to 30 μm. When the thickness of the fuel electrode 12 is 1 μm or more, a three-layer interface as the fuel electrode 12 is sufficiently formed. Further, when the thickness of the fuel electrode 12 is 30 μm or less, interfacial peeling due to a difference in thermal expansion from the solid electrolyte 13 can be prevented.

The solid electrolyte 13 provided on the main surface of the fuel electrode 12 is made of yttria-stabilized zirconia YSZ (dense ceramic) containing yttria (Y ₂ O ₃ ). The thickness of the solid electrolyte 13 is desirably 0.5 to 100 μm. Gas permeation can be prevented when the thickness of the solid electrolyte 13 is 0.5 μm or more. Moreover, the increase in a resistance component can be suppressed because the thickness of the solid electrolyte 13 is 100 micrometers or less.

The air electrode 14 is a lanthanum-manganese oxide, lanthanum-iron oxide, lanthanum-cobalt oxide of a transition metal perovskite oxide, or at least one porous conductive material of a composite oxide thereof. Made of ceramics. The air electrode 14 is preferably a (La, Sr) (Fe, Co) O ₃ system from the viewpoint of high electrical conductivity in the middle temperature range of about 800 ° C. The thickness of the air electrode 14 is preferably 10 to 100 μm from the viewpoint of current collection.

  The interconnector 16 is a dense body in order to prevent leakage of fuel gas and oxygen-containing gas between the inside and outside of the conductive support 11. Moreover, since the inner and outer surfaces of the interconnector 16 are in contact with the fuel gas and the oxygen-containing gas, respectively, they have reduction resistance and oxidation resistance.

  The thickness of the interconnector 16 is desirably 30 to 200 μm. When the thickness of the interconnector 16 is 30 μm or more, gas permeation can be completely prevented, and when it is 200 μm or less, an increase in resistance component can be suppressed.

For example, a bonding layer made of Ni and ZrO ₂ or Y ₂ O ₃ may be interposed between the end portion of the interconnector 16 and the end portion of the solid electrolyte 13 in order to improve the sealing performance.

  In the cell 100, the dense solid electrolyte 13 is not only on one main surface of the conductive support 11, but also on the side end surface of the interconnector 16 on the other main surface via the side end portion of the conductive support 11. Is formed. That is, the solid electrolyte 13 is extended to the other main surface of the conductive support 11 so as to form the side ends B, B on both sides, and is joined to the interconnector 16. Note that the side ends B and B (side ends of the conductive support 11) have curved shapes that protrude outward in the width direction in order to relieve the thermal stress that occurs due to heating and cooling associated with power generation. It is desirable.

  Next, a method for manufacturing the cell 100 as described above will be described. First, rare earth element oxide powder excluding La, Ce, Pr, and Nd elements and Ni and / or NiO powder are mixed. A conductive support material in which an organic binder and a solvent are mixed is extruded into this mixed powder to produce a plate-shaped conductive support molded body. This molded body is dried and degreased.

In addition, a sheet-like solid electrolyte molded body is produced using a solid electrolyte material in which a ZrO ₂ powder in which a rare earth element (Y) is dissolved, an organic binder, and a solvent are mixed.

Next, a slurry to be the fuel electrode 12 prepared by mixing Ni and / or NiO powder, ZrO ₂ powder in which a rare earth element is solid-solved, an organic binder, and a solvent is formed into the solid electrolyte molded body. Applied to one side. Thereby, a fuel electrode molded body is formed on one surface of the solid electrolyte molded body.

  Next, the conductive support body is formed such that a laminate of the sheet-like solid electrolyte formed body and the fuel electrode body is in contact with the conductive electrode body. It is wound around the compact.

  Next, several layers of the sheet-like solid electrolyte molded body are laminated on the solid electrolyte molded body at the position where the side end portions B and B of the laminated molded body are formed, and dried. Moreover, the slurry used as the solid electrolyte 13 may be screen-printed on the solid electrolyte molded body. In addition, degreasing may be performed at this time.

  Next, a sheet-like interconnector molded body is produced using an interconnector material in which a lanthanum-chromium oxide powder, an organic binder, and a solvent are mixed.

Moreover, a sheet-like intermediate film molded body is produced using a slurry in which Ni and / or NiO powder, a ZrO ₂ powder in which a rare earth element is dissolved, an organic binder, and a solvent are mixed.

  Next, the interconnector molded body and the intermediate film molded body are laminated. The laminate is laminated on the conductive support molded body so that the intermediate film molded body side of the laminate is in contact with the exposed conductive support molded body side.

  Thereby, the fuel electrode molded body and the solid electrolyte molded body are sequentially laminated on one main surface of the conductive support molded body, and the intermediate film molded body and the interconnector molded body are laminated on the other main surface. A body is made. Each molded body can be produced by sheet molding by a doctor blade, printing, slurry dip, spraying by spraying, and the like. Moreover, each molded object can be produced by these combinations.

  Next, the laminated molded body is degreased and cofired at 1300 to 1600 ° C. in an oxygen-containing atmosphere.

  Next, a transition metal perovskite oxide powder, which is a P-type semiconductor, and a solvent are mixed to produce a paste. The laminate is immersed in this paste. An air electrode molded body and a current collector film molded body are formed on the surfaces of the solid electrolyte 13 and the interconnector 16 by dipping or direct spray application, respectively. These molded bodies are baked at 1000 to 1300 ° C., whereby the cell 100 is manufactured.

  At this time, the Ni component in the conductive support 11, the fuel electrode 12, and the intermediate film 15 is NiO by firing in an oxygen-containing atmosphere. Therefore, in order to acquire these electroconductivity, after that, reducing fuel gas is flowed from the electroconductive support body 11 side, and NiO is reduced at 800-1000 degreeC over 1 to 10 hours. This reduction process may be performed during power generation.

(Example of overall structure of stack structure)
Next, a stack structure of a solid oxide fuel cell (SOFC) according to an embodiment of the present invention using the above-described cell 100 will be described. As shown in FIG. 2, the stack structure includes a large number of cells 100 and a fuel gas manifold 200 for supplying a fuel gas to each of the large number of cells 100. The entire manifold 200 is made of a material such as stainless steel.

  The top plate of the manifold 200 (in other words, the top plate (flat plate) of the gas tank) also serves as a support plate 210 for supporting a large number of cells 100. The manifold 200 is provided with an introduction passage 220 for introducing fuel gas from the outside into the internal space of the manifold 200. One end of each cell 100 in the first longitudinal direction so that each cell 100 protrudes in parallel along the first longitudinal direction (z-axis direction) from the surface of the support plate 210 and the plurality of cells 100 are aligned in a stack. The part is joined and supported by the support plate 210 (details of the joining structure will be described later). The other end portion of each cell 100 in the first longitudinal direction is a free end. Therefore, this stack structure can be expressed as a “cantilever stack structure”.

As shown in FIG. 3, a large number of insertion holes 211 communicating with the internal space of the manifold 200 are formed on the surface of the support plate 210 (the top plate of the manifold 200). One end of the corresponding cell 100 is inserted into each insertion hole 211 and fixed using a bonding material. As the bonding material, crystallized glass is preferably used, but amorphous glass, metal brazing material, or the like may be used. As the crystallized glass, for example, SiO ₂ —MgO-based glass is preferable. As a result, one end of the gas flow path 18 of each cell 100 communicates with the internal space of the manifold 200.

  As shown in FIG. 4, between adjacent cells 100, 100, between adjacent cells 100, 100 (more specifically, the fuel electrode 12 side of one cell 100 and the air electrode 14 of the other cell 100). A connecting member 300 for electrically connecting the side) in series. Specifically, each connection member 300 is bonded to the air electrode 14 of one cell of the adjacent cells 100, 100 and the current collector film 17 of the other cell using a bonding material. As this bonding material, a material having electron conductivity is used. For example, a “conductive paste” produced by mixing a transition metal perovskite oxide powder and a solvent can be used. The connection member 300 is made of a metal such as stainless steel, for example. Details of the shape of the connecting member 300 will be described later.

  As described above, when the cantilever stack structure of the fuel cell described above is operated, as shown in FIG. 5, the fuel gas (eg, hydrogen) at a high temperature (eg, 600 to 800 ° C.) and the “gas containing oxygen (eg, air) ) ". The fuel gas introduced from the introduction passage 220 moves to the internal space of the manifold 200 and is then introduced into the gas flow path 18 of the corresponding cell 100 via each insertion hole 211. The fuel gas that has passed through each gas flow path 18 is then discharged to the outside from the other end (free end) of each gas flow path 18. Air flows in the width direction (x-axis direction) of the cells 100 along the gaps between the adjacent cells 100 in the stack structure.

  The above-mentioned cantilever stack structure is assembled by the following procedure, for example. First, the required number of completed cells 100, the completed manifold 200, and the required number of completed connection members 300 are prepared. In addition, a glass bonding paste for bonding the cell 100 and the manifold 200 and a conductive bonding paste for bonding the cell 100 and the connecting member 300 are prepared.

  Next, using a predetermined jig, each connection member 300 is inserted between the adjacent cells 100, 100 while one end of each of the plurality of cells 100 is inserted into the corresponding insertion hole 211 of the support plate 210. Intervening / arranging, and corresponding bonding surfaces are bonded together with a conductive bonding paste. Next, the glass bonding paste is filled in the respective gaps at the bonding portion between the insertion hole 211 and one end of the cell 100.

  Subsequently, the bonding material is solidified by applying heat treatment to the paste to solidify the paste. As a result, one end of each cell is joined and fixed to the corresponding insertion hole 211. In other words, one end of each cell 100 is joined and supported by the support plate 210 using a glass joining material. In addition, each connection member 300 is bonded and fixed between the corresponding adjacent cells 100, 100 by using a conductive bonding material between the air electrode 14 of one cell and the current collecting film 17 of the other cell. . As a result, the adjacent cells 100 are connected electrically in series via the connection member 300. Thereafter, the predetermined jig is removed from the plurality of cells 100 to complete the above-described cantilever stack structure.

(Shape of connecting member)
Hereinafter, the three-dimensional shape of the connection member 300 will be described in detail with reference to FIGS. 6 and 7. As shown in FIG. 6, the connection member 300 includes a pair of fixing portions 310 and 310, and a connecting portion 320 that connects the pair of side end portions 311 and 311 that are part of the pair of fixing portions 310 and 310. Composed.

  The pair of fixing portions 310 and 310 are a pair of flat plate-like portions facing each other in parallel with a space in the y-axis direction. One of the pair of fixing portions 310 and 310 is joined to one air electrode 14 of the adjacent cells 100 and 100, and the other of the pair of fixing portions 310 and 310 is the other of the adjacent cells 100 and 100. The current collector film 17 is joined. The pair of side end portions 311 and 311 are regions extending in the z-axis direction at the end portion on the x-axis negative direction side of the pair of fixed portions 310 and 310, and are spaced apart from each other in the y-axis direction. It is a pair of strip-shaped parts facing each other in parallel.

  The connection part 320 has a first extension part and a second extension part 323. The first extending portion includes a pair of first portions 321 and 321 extending from the z-axis positive direction side end portion of the pair of side end portions 311 and 311 toward the x-axis negative direction side, and a pair of first portions. It is comprised from a pair of 2nd part 322,322 each extended toward a z-axis negative direction side from a pair of front-end | tip part in the front end side (x-axis negative direction side) of the part 321,321. The pair of first portions 321 and 321 and the pair of second portions 322 and 322 are both a pair of strip-shaped portions facing each other in parallel with a space in the y-axis direction.

  The second extending portion 323 has a strip shape extending in the y-axis direction, and connects the pair of tip portions on the tip side (z-axis negative direction side) of the pair of second portions 322 and 322.

  A connecting member 300 shown in FIG. 6 is a thin plate-like member produced in the shape shown in FIG. 7 by cutting, punching, or the like, and a boundary line between the second extending portion 323 and the pair of second portions 322 and 322. Are completed by bending each along a right angle.

  In the thin plate-like member shown in FIG. 7, “a direction (paper surface) perpendicular to the extending direction (left and right direction of the paper surface) of the main surface (plane parallel to the paper surface) corresponding to the first portion 321. (Vertical direction) width A21 "," direction (right and left direction on the paper surface) orthogonal to the extending direction (up and down direction on the paper surface) of the main surface (plane parallel to the paper surface) corresponding to the second portion 322 " ) And a direction orthogonal to the extending direction of the second extending portion 323 (left and right direction on the drawing) in the main surface (a plane parallel to the drawing surface) corresponding to the second extending portion 323. The width A23 "(up and down direction in the drawing) is all greater than the plate thickness of the thin plate member shown in FIG.

(Action / Effect)
Hereinafter, the operation and effect of the connection member 300 having the above three-dimensional shape will be described with reference to FIGS. In the stack structure described above, three-dimensional relative displacement (relative position shift, relative position shift, etc.) inevitably occurs between adjacent cells 100 and 100 during SOFC operation. Can do. In addition, between the adjacent cells 100, 100, a pair of fixing portions 310, 310 are joined and fixed to the corresponding cells 100, respectively. This means that in the connection member 300 shown in FIG. 6, a three-dimensional relative displacement (relative positional deviation, relative positional deviation, etc.) is unavoidable between the pair of fixing portions 310, 310. It also means that it can occur.

  Here, as shown in FIG. 8, the connection member 300 has low rigidity against “elastic deformation accompanied by relative rotational displacement as seen from the z-axis direction between the pair of fixing portions 310, 310”. This is because when the pair of fixing portions 310, 310 relatively receive a moment around the z-axis, the bending rigidity of the pair of first portions 321 and 321 and the torsional rigidity of the pair of second portions 322 and 322, And it is based on the bending rigidity of the 2nd extension part 323 being low.

  Further, as shown in FIG. 9, the connection member 300 has low rigidity against “elastic deformation accompanying relative rotational displacement as seen from the x-axis direction between the pair of fixing portions 310, 310”. This is because the torsional rigidity of the pair of first portions 321 and 321 and the bending of the pair of second portions 322 and 322 when the pair of fixing portions 310 and 310 receive a moment about the x axis relatively. Based on low stiffness.

  Furthermore, as shown in FIG. 10, the connection member 300 has low rigidity against “elastic deformation accompanying relative rotational displacement as seen from the y-axis direction between the pair of fixing portions 310, 310”. This is based on the fact that the torsional rigidity of the second extending portion 323 is low when the pair of fixing portions 310 and 310 receive a moment around the y-axis relatively.

  As described above, the connection member 300 has low rigidity with respect to all of “elastic deformation accompanying relative rotational displacements between the pair of fixing portions 310 and 310 viewed from the three axial directions of the x axis, the y axis, and the z axis”. Accordingly, it can be said that the connection member 300 has low rigidity against “elastic deformation that causes a three-dimensional relative displacement between the pair of fixing portions 310, 310”. As a result, even if a three-dimensional relative displacement occurs between the adjacent cells 100, 100, the “pair of fixing members 310, 310 of the connecting member” and the “cell 100 ( The stress acting on the joint portion with the power generating element portion) is reduced. As a result, the reliability at the joint is increased.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, in the above embodiment, the connection member 300 has the shape shown in FIGS. 6 and 7, but even if the connection member 300 having the shape shown in FIGS.・ Effects are produced.

  The connection member 300 shown in FIGS. 11 and 12 differs from the connection member 300 shown in FIGS. 6 and 7 only in the orientation of the plane of the second extending portion 323. A connection member 300 shown in FIG. 11 is a thin plate-like member produced in the shape shown in FIG. 12 by cutting, punching, or the like, and is a boundary line between the second extending portion 323 and the pair of second portions 322 and 322. Are completed by bending each along a right angle.

  In the thin plate-like member shown in FIG. 12, “a direction (paper surface) perpendicular to the extending direction (the vertical direction on the paper surface) of the first portion 321 on the main surface (plane parallel to the paper surface) corresponding to the first portion 321. (Width A21 in the left-right direction) "," direction (vertical direction on the paper surface) perpendicular to the extending direction (left-right direction on the paper surface) of the main surface (plane parallel to the paper surface) of the portion corresponding to the second portion 322 " ) And a direction orthogonal to the extending direction of the second extending portion 323 (left and right direction on the drawing) in the main surface (a plane parallel to the drawing surface) corresponding to the second extending portion 323. All the widths A <b> 23 (in the vertical direction on the paper surface) ”are larger than the plate thickness of the thin plate member shown in FIG.

  Further, even when the connection member 300 having the shape shown in FIGS. 13 and 14 is employed, the same operations and effects as described above are exhibited. The connection member 300 shown in FIGS. 13 and 14 is such that the first extending portion is an end portion on the z-axis positive direction side of the pair of side end portions 311 and 311 with respect to the connection member 300 shown in FIGS. The difference is that only a pair of first portions 321 and 321 extending obliquely toward the “x-axis negative direction and the z-axis negative direction side” are provided. A connecting member 300 shown in FIG. 13 is a thin plate-like member produced in the shape shown in FIG. 14 by cutting, punching, or the like, and a boundary line between the second extending portion 323 and the pair of first portions 321 and 321. Are completed by bending each along a right angle.

  In the thin plate-like member shown in FIG. 14, “a direction orthogonal to the extending direction of the first portion 321 (the oblique direction of the paper surface) on the main surface (a plane parallel to the paper surface) corresponding to the first portion 321 ( Width A21 "in the diagonal direction of the paper) and" in the main surface (a plane parallel to the paper surface) of the portion corresponding to the second extension 323 in the extending direction (left and right direction of the paper) of the second extending portion 323 ". All the widths A <b> 23 ”in the orthogonal direction (the vertical direction on the paper surface) are larger than the plate thickness of the thin plate member shown in FIG. 14.

  Moreover, the connection member 300 which has a shape shown in FIG. 15, FIG. 16 may be employ | adopted. The connection member 300 shown in FIGS. 15 and 16 is different from the connection member 300 shown in FIGS. 6 and 7 in that the first extension portion does not exist and the second extension portion is “a pair of side end portions. 311 and 311 are different in that they constitute the whole of the connecting portion 320 ”that connects the ends on the z-axis positive direction side. A connecting member 300 shown in FIG. 15 is a thin plate-like member produced in the shape shown in FIG. 16 by cutting, punching, or the like along the boundary line between the connecting portion 320 and the pair of side end portions 311 and 311. Each is completed by folding at right angles.

  In the thin plate-like member shown in FIG. 16, “a direction (vertical direction on the paper surface) perpendicular to the extending direction (left and right direction on the paper surface) of the main surface (a plane parallel to the paper surface) corresponding to the connection portion 320. ) ”Is larger than the plate thickness of the thin plate member shown in FIG.

  Moreover, the connection member 300 having the shape shown in FIGS. 17 and 18 may be employed. The connection member 300 shown in FIGS. 17 and 18 is different from the connection member 300 shown in FIGS. 6 and 7 in that the first extension portion does not exist and the second extension portion is “a pair of side end portions. 311 and 311 are different in that they constitute the whole of the connecting portion 320 ”that connects the central portions excluding both ends in the z-axis direction. A connecting member 300 shown in FIG. 17 is a thin plate-like member produced in the shape shown in FIG. 18 by cutting, punching, or the like along the boundary line between the connecting portion 320 and the pair of side end portions 311 and 311. Each is completed by folding at right angles.

  In the thin plate-like member shown in FIG. 18, “a direction (vertical direction on the paper surface) orthogonal to the extending direction (left and right direction on the paper surface) of the main surface (a plane parallel to the paper surface) corresponding to the connection portion 320. ) Width A20 "is larger than the plate thickness of the thin plate member shown in FIG.

  As described above, in the connection member 300 according to the above-described embodiment and the modifications of the various connection members 300 illustrated in FIG. 11 to FIG. The length of the portion connected to the portions 321 and 321) in the z-axis direction is the length that the entire pair of side end portions 311 and 311 extends in the z-axis direction (= the fixed portion 310 is in the z-axis direction). 5 to 50% of the extended height). Further, in the connecting portion 320, portions extending in the x-axis, y-axis, and z-axis directions may extend in directions slightly shifted from the x-axis, y-axis, and z-axis directions, respectively. Further, the pair of fixing portions 310 and 310 do not have to be parallel to each other as long as they face each other with a space therebetween.

  In the above-described embodiment, a so-called “vertical stripe” is formed by stacking a plurality of cells each provided with only one “power generation element portion in which a fuel electrode, a solid electrolyte, and an air electrode are stacked in this order” on the surface of the support substrate. Although the structure of the "type" is adopted, the so-called "horizontal stripe type" in which the power generation element portions are respectively provided at a plurality of positions separated from each other on the surface of the support substrate and the adjacent power generation element portions are electrically connected to each other. May be adopted. Moreover, in the cell of the said embodiment, you may replace a fuel electrode and an air electrode. In this case, a gas flow in which the fuel gas and air are interchanged in FIG. 5 is employed.

  In the above embodiment, the top plate of the manifold also serves as a support plate for supporting a large number of cells (that is, the support plate is integrally formed with the manifold). As long as the gas flow paths of the cells communicate with each other, the support plate may be configured separately from the manifold.

  Furthermore, in the said embodiment, although the connection member 300 is comprised so that between the electric power generation element parts of the adjacent cells 100 and 100 may be comprised, FIG. 19 each corresponding to FIGS. As shown in FIG. 21, the connection member 300 may be configured to electrically connect the power generation element portions respectively provided on the front and back of one cell 100. In this case, the power generating element portions of the adjacent cells 100 and 100 are electrically connected by another connection member (not shown).

  DESCRIPTION OF SYMBOLS 11 ... Electroconductive support body, 12 ... Fuel electrode, 13 ... Solid electrolyte, 14 ... Air electrode, 18 ... Gas flow path, 100 ... Cell, 200 ... Manifold, 210 ... Support plate, 211 ... Insertion hole, 300 ... Connection member , 310 ... fixing part, 311 ... side end part, 320 ... connecting part, 321 ... first part, 322 ... second part, 323 ... second extension part

Claims (7)

A plurality of cells each comprising a power generation element portion including an inner electrode, a solid electrolyte, and an outer electrode;
A support member for supporting the plurality of cells such that the plurality of cells are arranged in a stack at intervals;
A connection member made of a conductive member, which is provided between the adjacent cells and electrically connects between the power generation element portions of the adjacent cells;
In a fuel cell stack structure comprising:
The connecting member is
A pair of fixed portions facing each other with a space therebetween, each fixed to a corresponding cell of the adjacent cells and electrically connected to the power generating element portion of the corresponding cell;
A pair of side end portions on one side of the first direction in the pair of fixed portions, each extending in a second direction different from the first direction and facing each other with a space therebetween , A connecting part for connecting,
With
The connection portion is only the one end portion in the second direction in the pair of side end portions, or only the central portion excluding both end portions in the second direction in the pair of side end portions. A stack structure of a fuel cell connecting the side ends of the fuel cell. The fuel cell stack structure according to claim 1,
The connecting portion is
A pair of first extending portions respectively extending from one end portion of the second direction in the pair of side end portions toward one side in the first direction and the other side in the second direction;
Extending in a third direction different from the first and second directions from a pair of tip portions on the tip side of the pair of first extension portions, the tip portions of the pair of first extension portions are connected to each other. A second extension,
A fuel cell stack structure. The fuel cell stack structure according to claim 2,
The first extending portion is
A pair of first portions respectively extending from one end portion of the second direction in the pair of side end portions toward one side of the first direction;
A pair of second portions respectively extending from the pair of tip portions on the tip side of the pair of first portions toward the other side in the second direction;
With
The second extending portion is a fuel cell stack structure that connects a pair of tip portions on the tip side of the pair of second portions. In the fuel cell stack structure according to claim 2 or 3,
The pair of fixing portions has a pair of flat plate-like shapes facing each other at an interval,
A stack structure of a fuel cell, wherein the first, second and third directions are perpendicular to each other. The fuel cell stack structure according to any one of claims 1 to 4,
The connecting member is formed by bending a thin plate-like member,
A stack structure of a fuel cell, wherein a width of the thin plate-like member in a direction orthogonal to the extending direction of the portion on a main surface of a portion corresponding to the connecting portion is larger than a thickness of the thin plate-like member. The fuel cell stack structure according to any one of claims 1 to 5,
Each of the cells includes a support substrate that has a flat plate shape having a longitudinal direction and in which a gas flow path is formed along the longitudinal direction.
The power generation element portion is provided on the surface of each support substrate,
The support member is
One end of each cell in the longitudinal direction is arranged so that each cell protrudes from the surface of the support member along the longitudinal direction and the plurality of cells are arranged in a stack at intervals. It is a support plate to join and support,
A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
A fuel cell stack structure in which each connecting member is disposed and fixed between adjacent cells so that the longitudinal direction coincides with the second direction. The power generation element portion including the inner electrode, the solid electrolyte, and the outer electrode is provided in a flat plate shape provided on the first main surface side and the second main surface side opposite to the first main surface side. Cell,
A connection member made of a conductive member that electrically connects the power generation element portion provided on the first main surface side and the power generation element portion provided on the second main surface side. When,
A fuel cell assembly comprising:
The connecting member is
One is electrically connected to the power generating element provided on the first main surface, and the other is electrically connected to the power generating element provided on the second main surface. A pair of fixed portions facing each other at an interval;
A pair of side end portions on one side of the first direction in the pair of fixed portions, each extending in a second direction different from the first direction and facing each other with a space therebetween , A connecting part for connecting,
With
The connection portion is only the one end portion in the second direction in the pair of side end portions, or only the central portion excluding both end portions in the second direction in the pair of side end portions. A fuel cell assembly connecting the side ends of the fuel cell.