JP2014143052A - Solid electrolyte fuel cell unit and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a power generation cell from being broken by welding distortion and residual stress.SOLUTION: A separator and a passage formation member are welded together to form a separator unit, then a seal material is provided on a cell support surface of the separator unit, a power generation cell is mounted on the seal material, and the seal material is heated together with the separator unit and the power generation cell to be fired. Thus the separator unit and the power generation cell are directly bonded.

Description

  The present invention relates to a solid oxide fuel cell unit and a method for manufacturing the same.

  Patent Document 1 discloses a fuel cell unit including a solid electrolyte type power generation cell. The fuel cell unit includes a cell plate in which an inner peripheral side and an outer peripheral side of a ring-shaped ceramic power generation cell are supported by two annular metal substrates, and a cell plate disposed opposite to the cell plate. And a metal separator plate that forms a gas flow path therebetween.

JP 2005-353421 A

  However, in the fuel cell unit, after the power generation cells are joined to the metal substrate to form the cell plate, the outer peripheral portion of the cell plate (specifically, the outer peripheral portion of the metal substrate that supports the outer peripheral side of the power generation cell) And the outer peripheral portion of the separator plate are directly joined by welding. For this reason, thermal deformation during welding and deformation due to shrinkage after welding (welding deformation such as warpage and strain) that acts on the separator plate and the metal substrate act on the power generation cell, causing the power generation cell to crack or residual stress on the power generation cell. There was a risk of occurrence.

  An object of the present invention is to provide a solid oxide fuel cell unit capable of preventing damage to a power generation cell due to welding deformation or residual stress, and a method for manufacturing the same.

  One aspect of the present invention is a method for manufacturing a solid oxide fuel cell unit including a separator, a flow path forming member, and a power generation cell. In this manufacturing method, first, a separator and a flow path forming member are welded together to form a separator unit. Thereafter, a separator is provided on the cell support surface of the separator unit, a power generation cell is placed thereon, the sealant is heated together with the separator unit and the power generation cell, and the sealant is baked, thereby separating the separator unit and the power generation cell. Join directly.

    According to the above manufacturing method, after the flow path forming member and the separator are welded to each other to form the separator unit, the power generation cell is directly joined to the separator unit by the sealing material. That is, the power generation cell is joined to the separator unit after the welding step of the manufacturing process of the solid oxide fuel cell unit is completed, and the solid oxide fuel cell unit is attached to the separator unit after the power generation cell joining step. There is no need to weld. For this reason, it can prevent that the deformation | transformation by the thermal deformation at the time of welding or the shrinkage | contraction after welding acts on a power generation cell, and can prevent the power generation cell from being damaged by these.

1A and 1B are diagrams showing a solid oxide fuel cell unit according to a first embodiment of the present invention, in which FIG. 1A is a plan view, FIG. 1B is a sectional view taken along line AA in FIG. FIG. 3 is a sectional view taken along line BB in FIG. FIG. 2 is an exploded perspective view of the solid oxide fuel cell unit of FIG. FIG. 3 is a diagram showing a structure of a fuel cell stack formed by stacking a plurality of solid oxide fuel cell units of FIG. FIG. 4 is a diagram for explaining a method of manufacturing the solid oxide fuel cell unit of FIG. FIG. 5 is a cross-sectional view showing a solid oxide fuel cell unit according to the second embodiment of the present invention. The left half shows a cross section corresponding to the cross section along line AA in FIG. These show the cross section corresponding to the BB line cross section of Fig.1 (a). FIG. 6 is a diagram for explaining a method of manufacturing the solid oxide fuel cell unit of FIG. FIG. 7 is a cross-sectional view showing a solid oxide fuel cell unit according to the third embodiment of the present invention, in which the left half shows a cross section corresponding to the cross section along line AA in FIG. These show the cross section corresponding to the BB line cross section of Fig.1 (a). FIG. 8 is a diagram for explaining a method of manufacturing the solid oxide fuel cell unit of FIG. FIG. 9 is an exploded perspective view of the solid oxide fuel cell unit according to the fourth embodiment of the present invention. FIG. 10 is a cross-sectional view showing the solid oxide fuel cell unit of FIG. 9, wherein the left half shows a cross section corresponding to the cross section along line AA of FIG. 1 (a), and the right half shows FIG. ) Shows a cross section corresponding to a cross section taken along line B-B. FIG. 11 is a diagram for explaining a method of manufacturing the solid oxide fuel cell unit of FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The technical scope of the present invention should be determined based on the description of the scope of claims, and is not limited only to the following embodiments. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio. In addition, the terms indicating directions such as “up” and “down” in the following description are defined for convenience in order to describe the positional relationship of each part, and the actual mounting posture of the device is not limited to this. Absent.

<First Embodiment>
A cell unit U1, which is a solid oxide fuel cell unit according to the first embodiment of the present invention, will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the cell unit U <b> 1 includes a power generation cell 1, a separator 2, and a flow path forming member 3 welded to the center of the separator 2.

  As shown in FIG. 1, the power generation cell 1 includes an electrolyte membrane 4 made of a solid electrolyte, an anode electrode layer (anode electrode) 5 provided on one surface of the electrolyte membrane 4, and the other side of the electrolyte membrane 4. It is comprised from the cathode electrode layer (cathode electrode) 6 provided in the surface. The electrolyte membrane 4 is a dense ceramic material having oxygen ion conductivity, and has electrical insulation. As a material of the electrolyte membrane 4, for example, yttria-stabilized zirconia can be used. Moreover, as a material of the anode electrode layer 5, for example, cermet of nickel and yttria stabilized zirconia can be used, and as a material of the cathode electrode layer 6, for example, lanthanum strontium cobalt iron can be used.

  The power generation cell 1 generates power by supplying a fuel gas such as hydrogen or natural gas to the anode electrode layer 5 and supplying an oxidant gas such as air to the cathode electrode layer 6. The anode electrode layer 5 and the cathode electrode layer 6 are formed to be porous in order to permeate these reaction gases (a general term for fuel gas and oxidant gas).

  As shown in FIGS. 1 and 2, the power generation cell 1 is formed in an annular plate shape having a circular hole 1 a at the center. In the present embodiment, the cathode electrode layer 6 is not provided on the entire other surface of the electrolyte membrane 4, and the outer diameter of the cathode electrode layer 6 (the diameter of the outer peripheral end) is smaller than the outer diameter of the electrolyte membrane 4. Further, the inner diameter (inner peripheral end diameter) of the cathode electrode layer 6 is larger than the inner diameter of the hole in the central portion of the electrolyte membrane 4. For this reason, the surface of the electrolyte membrane 4 on the cathode electrode layer 6 side is exposed at the outer peripheral portion and the inner peripheral portion of the power generation cell 1.

  The separator 2 is disposed facing the power generation cell 1 in the stacking direction and supports the power generation cell 1. Further, as shown in FIG. 3, the separator 2 is sandwiched between the power generation cells 1 of the cell units U1 adjacent to each other in the stacking direction, and comes into contact with the electrode layers 5 and 6 of the power generation cells 1 to This constitutes a current path between the units U1.

  The separator 2 is formed by pressing a thin plate material made of ferritic stainless steel (for example, SUS430) and is formed into an annular plate shape as a whole as shown in FIG. Is almost equal to the outer diameter of The material of the separator 2 is not particularly limited, but it is preferable to use a material that has excellent heat resistance and a thermal expansion coefficient close to that of the power generation cell 1.

  An area of the separator 2 that faces the power generation area of the power generation cell 1 is a gas flow path portion 7 for forming gas flow paths 7 a and 7 b that extend along the power generation cell 1. The gas flow path portion 7 is provided with a wave shape, and a plurality of ridges 8 a and ridges 8 b each extending in a substantially semicircular arc shape are alternately arranged in the radial direction of the power generation cell 1. The top of each ridge 8a is in contact with the cathode electrode layer 6 of the power generation cell 1 (direct line contact), thereby extending continuously in the circumferential direction of the power generation cell 1 between the ridges 8a. A gas flow path 7a for the existing oxidant gas is formed. Further, the bottom of each concave strip 8b (the top of each convex strip 8a when the separator 2 is viewed from below) abuts (directly) the anode electrode layer 5 of the power generation cell 1 of the cell unit U1 adjacent in the stacking direction. Line contact). Thereby, the gas flow path 7b for fuel gas which extends continuously in the circumferential direction between the plurality of recesses 8b is formed.

  Further, at two locations in the circumferential direction of the separator 2, there are provided the header flow path portions 9 that are not formed with the convex stripes 8 a and the concave stripes 8 b and have a flat shape. The bottom wall 9c of the header channel portion 9 is located at a substantially intermediate position of the height of the separator 2 (distance in the stacking direction from the top of the ridge 8a to the bottom of the ridge 8b) (FIG. 1B). )reference). Header flow paths 9 a and 9 b extending in the radial direction of the separator 2 are formed above and below the header flow path portion 9. The upper header channel 9a communicates with a plurality of gas channels 7a for the oxidant gas defined between the ridges 8a. On the other hand, the lower header flow path 9b communicates with a plurality of fuel gas flow paths 7b defined between the recesses 8b, and the radially outer end thereof has a diameter of the cell unit U1. It opens toward the outside in the direction.

  Further, a flange 10 formed by bending the outer peripheral portion outward is provided on the outer peripheral portion of the separator 2. The flange 10 extends so as to surround the entire periphery of the gas flow path portion 7 in a plan view, and supports the outer peripheral portion of the power generation cell 1 with its upper surface (cell support surface) 10a. Moreover, the sealing material 11 is apply | coated to the upper surface 10a of the flange 10, and the outer peripheral part whole periphery of the electric power generation cell 1 is directly joined there, and the radial direction outer side edge part of the gas flow path in a unit is sealed. .

  In addition, at the joint between the outer peripheral portion of the power generation cell 1 and the flange 10 of the separator 2, as shown in FIG. 1, the flange 10 is directly on the electrolyte membrane 4 of the power generation cell 1 (the cathode electrode layer 6 and other sealing materials). (Without any member other than 11). The upper surface of the sealing material 11 is in contact only with the electrolyte membrane 4 of the power generation cell 1.

  In the present embodiment, two upper header channels 9a, a plurality of gas channels 7a, and two through channels 33 formed in a channel forming member 3 described later are introduced into the cell unit U1. The in-unit gas flow path for circulating the reacted gas in the cell unit U1 is configured. The cell unit U1 includes two header channels 9b formed on the lower side of the header channel 9 and a plurality of gas channels 7b defined between the recesses 8b in the stacking direction. An inter-unit gas flow path for circulating the reaction gas introduced therebetween is configured. That is, in the present embodiment, the separator 2 has a function of defining the in-unit gas flow path and the inter-unit gas flow path and separating both flow paths from each other.

  Further, a bolt hole 12 through which a later-described through bolt 50 passes and a pair of C-shaped gas passage holes 13 disposed so as to sandwich the bolt hole 12 are provided in the central portion of the separator 2. A flow path forming member 3 is welded to the upper surface of the central portion of the separator 2. The welding used is, for example, laser welding using a YAG laser, and the flow path forming member 3 is joined by irradiating the laser from the lower surface of the central portion of the separator 2. In addition to the above laser welding, resistance heating welding, arc welding, or the like can be used for welding.

  The flow path forming member 3 is a member that defines the inlet and outlet of the reaction gas to the in-unit gas flow path while supporting the power generation cell 1, and is integrated with the separator 2 by welding to form the separator unit SU. Is configured. In the present embodiment, the flow path forming member 3 is a circular plate made of ferritic stainless steel (for example, SUS430) as shown in FIG. The outer diameter is smaller than the outer diameter of the separator 2 and the outer diameter of the power generation cell 1, and larger than the diameter of the circular hole 1 a provided in the central portion of the power generation cell 1.

  The thickness of the flow path forming member 3 is set such that when the flow path forming member 3 is welded to the separator 2, the upper surface 3 a of the outer peripheral portion thereof is substantially the same height as the flange 10 of the separator 2. A sealing material 11 is applied to the outer peripheral portion upper surface 3a, and the entire inner peripheral portion of the power generation cell 1 is directly joined thereto. That is, the outer peripheral part upper surface 3 a of the flow path forming member 3 constitutes a cell support surface that supports the inner peripheral part of the power generation cell 1.

  In addition, at the joint between the inner peripheral part of the power generation cell 1 and the outer peripheral part upper surface 3 a of the flow path forming member 3, the outer peripheral part upper surface 3 a directly contacts the electrolyte membrane 4 of the power generation cell 1 as shown in FIG. 1. They are joined (without interposing members other than the cathode electrode layer 6 and the sealing material 11). The upper surface of the sealing material 11 is in contact only with the electrolyte membrane 4 of the power generation cell 1.

  A bolt hole 31 and a gas passage hole 32 having the same shape as the bolt hole 12 and the gas passage hole 13 provided in the separator 2 are vertically arranged at the center of the flow path forming member 3. It is provided so as to penetrate in the direction (stacking direction).

  Further, at two locations in the circumferential direction of the flow path forming member 3, there are provided through passages 33 that penetrate the flow path forming member 3 in the radial direction. Each through passage 33 has a radially inner end opened on the inner peripheral surface of the gas passage hole 32 and a radially outer end opened on the radially outer side surface of the flow path forming member 3. Each opening at the radially outer end is disposed at a position facing the header flow path 9 a formed on the upper side of the separator 2 when the flow path forming member 3 is welded to the separator 2. The shape of the through passage 33 is not particularly limited as long as it communicates the in-unit gas flow path and gas passages SUP and DIS described later. In addition to the through hole, for example, the lower surface of the flow path forming member 3 It may be a channel groove provided on the (surface joined to the separator 2). The channel groove can be formed by etching, grinding, laser processing, or the like, or can be formed by stacking and joining etched parts.

  As shown in FIG. 1 and FIG. 3, the sealing material 11 is an electrically insulating or conductive paste-like bonding material provided on the cell support surface of the separator unit SU. The cell 1 and the separator unit SU are joined in an airtight manner. In addition, the material of the sealing material 11 can be appropriately selected in consideration of the difference in thermal expansion coefficient between the power generation cell 1 and the separator 2 constituting the separator unit SU. Examples of the bonding material having electrical insulation include a ceramic-based adhesive mainly composed of alumina and a glass-based bonding material mainly composed of silicon oxide. Examples of the conductive bonding material include a metal brazing material mainly composed of gold, silver, nickel, palladium, and the like.

  As shown in FIG. 3, the fuel cell stack S includes a stack SB formed by stacking a plurality of cell units U1 in the stacking direction, end plates 40 provided at both ends of the stack SB in the stacking direction, The plate 40 and the laminated body SB are configured to be pressed and clamped by the through bolts 50 penetrating the stacked body SB. An insulating spacer 60 is interposed between the cell units U1 of the stacked body SB.

  The insulating spacer 60 is made of an electrically insulating member, and is interposed between the cell units U1 adjacent in the stacking direction, and supports the central portions of the cell units U1 while being electrically insulated from each other. The insulating spacer 60 defines a radially inner boundary of the inter-unit gas flow path on the radially outer side surface, and supplies and discharges reaction gas to and from the unit gas flow path inside the insulating spacer 60. Gas passages SUP and DIS are defined.

  As shown in FIG. 2, the insulating spacer 60 has a circular plate shape, and the outer diameter thereof is smaller than the diameter of the circular hole 1 a provided in the central portion of the power generation cell 1. In the central portion of the insulating spacer 60, bolt holes 61 having the same shape as those at positions corresponding to the bolt holes 12, 31 and the gas passage holes 13, 32 provided in the separator 2 and the flow path forming member 3. The gas passage hole 62 is provided so as to penetrate in the vertical direction (stacking direction). The gas passage hole 62 provided in the insulating spacer 60, together with the gas passage holes 13 and 32 of each cell unit U1 constituting the stacked body SB, has two gas passages SUP, penetrating in the stacking direction of the fuel cell stack S. It constitutes DIS. In the present embodiment, one of the two gas passages is used as a gas supply gas passage SUP for supplying an oxidant gas to each cell unit U1, and the other is used for power generation from each cell unit U1. It is used as a gas discharge gas passage DIS for discharging the oxidant gas.

  As shown in FIG. 3, the end plate 40 is attached to both ends of the stacked body SB in the stacking direction, and pressurizes and holds the stacked body SB together with the through bolts 50. The upper end plate 40 is provided with a gas supply port 42 for supplying an oxidant gas to the gas supply gas passage SUP, in addition to a bolt hole 41 through which the through bolt 50 is inserted. Further, an oxidant gas supply path 44 for supplying an oxidant gas to the gas supply port 42 is connected to the upper end plate 40. On the other hand, the lower end plate 40 is provided with a gas discharge port 43 for discharging the oxidant gas from the gas discharge gas passage DIS. The lower end plate 40 is connected to an oxidant gas discharge path 45 for discharging the oxidant gas from the gas discharge port 43.

  As shown in FIG. 3, the oxidant gas is supplied from the oxidant gas supply path 44 into the gas supply gas passage SUP through the gas supply port 42. The oxidant gas in the gas passage SUP flows into the in-unit gas flow path through one of the through paths 33 provided in the flow path forming member 3 of each cell unit U1. The oxidant gas that has passed through the through passage 33 flows into one of the header channels 9 a provided in the separator 2, branches and flows into the plurality of gas channels 7 a, and then merges with the other header channel 9 a, The gas passes through the other through passage 33 provided in the flow passage forming member 3 and is discharged into the gas discharge gas passage DIS. The oxidant gas contacts the cathode electrode layer 6 of the power generation cell 1 and is used for power generation while it flows from one header flow path 9a to the other header flow path 9a through the plurality of gas flow paths 7a. .

  On the other hand, as shown in FIG. 3, the fuel gas is supplied to each inter-unit gas flow path from the radially outer side surface of the stacked body SB. Then, the fuel gas flows into one header flow path 9b that opens on the radially outer side surface of the stacked body SB, and then flows into a plurality of gas flow paths 7b, and then flows through the other header flow path 9b. It merges and is discharged from the opening outside in the radial direction. While the fuel gas flows from one header channel 9b to the other header channel 9b through the plurality of gas channels 7b, the fuel gas contacts the anode electrode layer 5 of the power generation cell 1 and is used for power generation.

  Moreover, each power generation cell 1 in the stacked body SB is electrically connected in series by a separator 2 sandwiched between the power generation cells 1 as shown in FIG. It can be taken out from the power generation cells 1 at both ends in the stacking direction through current collecting members (not shown).

  Hereinafter, the manufacturing method of the cell unit U1 according to the present embodiment will be described with reference to FIG.

  First, as shown in FIG. 4A, the flow path forming member 3 is welded to the upper surface of the central portion of the separator 2. Specifically, the separator 2 and the flow path forming member 3 are welded at a welding location indicated by an arrow in the drawing (a welding line continuous in the circumferential direction). Thereby, the separator unit SU in which the separator 2 and the flow path forming member 3 are integrated is formed.

  Next, as shown in FIG. 4B, the sealing material 11 is applied to the cell support surface of the separator unit SU, that is, the outer peripheral surface 3a of the flow path forming member 3 and the upper surface 10a of the flange 10 of the separator 2. .

  Next, as shown in FIG. 4C, the power generation cell 1 is placed on the applied sealing material 11. Thereby, the power generation cell 1 and the separator unit SU are directly joined (without interposing other members other than the sealing material 11) to form the cell unit U1. In the present embodiment, the electrolyte membrane 4 of the power generation cell 1 is placed on the upper surface of the flange 10 of the separator 2 while the cathode electrode layer 6 faces downward in the figure and the top of the protrusion 8 a of the separator 2 is in contact with the cathode electrode layer 6. 10a and the flow path forming member 3 are directly joined to the outer peripheral surface 3a.

  Next, as shown in FIG. 4D, the cell unit U1 is heated and the sealing material 11 is fired. The firing temperature and firing time are not particularly limited because they differ depending on the type of the sealing material 11 to be used. However, the firing temperature is set to about 800 to 900 ° C. for a glass-based bonding agent, for example, and the firing time is, for example, 20 It is set to about 60 minutes.

  When assembling the fuel cell stack S, first, a predetermined number of the cell units U1 formed as described above are stacked in the same direction with the insulating spacers 60 interposed therebetween to form a stacked body SB. End plates 40 are attached to both ends of the stacked body SB in the stacking direction. And the penetration bolt 50 is inserted in the bolt hole 12, 31, 61, 41 provided in the separator 2 and the flow path forming member 3, the insulating spacer 60, and the end plate 40 of each cell unit U1 constituting the stacked body SB. The plurality of cell units U1 are fastened and fastened by screwing the nuts 51 to their tips.

<Effect>
According to the cell unit U1 according to the present embodiment, the flow path forming member 3 and the separator 2 are welded to each other to form the separator unit SU, and then the power generation cell 1 is directly joined to the separator unit SU by the sealing material 11. ing. That is, the power generation cell 1 is joined to the separator unit SU after completion of the welding step in the manufacturing process of the cell unit U1, and after the joining step of the power generation cell 1, the metal part is attached to the cell unit U1. There is no need to perform welding. For this reason, it can prevent that the deformation | transformation by the thermal deformation at the time of welding and the shrinkage | contraction after welding acts on the power generation cell 1, and the power generation cell 1 is cracked by these factors, or residual stress arises in the power generation cell 1. Can be prevented. As described above, the firing temperature of the sealing material 11 is very low as compared with the welding temperature, and therefore the influence on the power generation cell 1 is sufficiently small.

  In this embodiment, after the separator unit SU is formed by welding, the power generation cell 1 is placed on the sealing material 11 provided in the separator unit SU, and the sealing material 11 is heated together with the separator unit SU and the power generation cell 1. The sealing material 11 is fired. For this reason, in this heating and firing step, the residual stress of the separator unit SU, which is a welded structure, can be removed simultaneously with firing of the sealing material 11.

  Furthermore, in this embodiment, since the power generation cell 1 is directly joined to the separator unit SU, the annular metal substrate that has been conventionally provided to support the inner peripheral side and the outer peripheral side of the power generation cell 1 can be omitted. Thereby, the number of parts of the cell unit U1 is reduced, the manufacturing process of the cell unit U1 is simplified, and the cell unit U1 can be reduced in weight and reduced in heat capacity.

  Further, in the present embodiment, when the power generation cell 1 and the separator unit SU are joined, the electrolyte membrane 4 which is a dense layer is attached to the cell support surface of the separator unit SU (the upper surface 10a of the flange 10 of the separator 2 and the flow path formation). The member 3 is directly joined to the outer peripheral surface 3a). For this reason, it can prevent reliably that the reaction gas (in this embodiment, oxidant gas) in the gas flow path in a unit leaks from the said junction part.

  Furthermore, in this embodiment, the sealing material 11 provided on the cell support surface of the separator unit SU is provided such that the surface on the power generation cell 1 side is in contact with only the electrolyte membrane 4 having electrical insulation. For this reason, even when a conductive bonding material is used as the sealing material 11, it is possible to ensure insulation between the anode electrode layer 5 and the cathode electrode layer 6. That is, by adopting the configuration of the present embodiment, the degree of freedom in selecting the sealing material 11 can be improved.

Second Embodiment
A cell unit U2 that is a solid oxide fuel cell unit according to a second embodiment of the present invention will be described with reference to FIG.

  Similar to the cell unit U1 according to the first embodiment, the cell unit U2 according to the present embodiment includes a power generation cell 1, a separator 2, and a flow path forming member 3 welded to the separator 2. As shown in FIG. 5, the cell unit U2 is a cell unit according to the first embodiment in that the sealing material 11 is also applied to the radially outer side surface 1b and the radially inner side surface 1c of the power generation cell 1. Different from U1. Since other configurations are the same as those in the first embodiment, the same members are denoted by the same reference numerals and detailed description thereof is omitted.

  Hereinafter, the manufacturing method of the cell unit U2 according to the present embodiment will be described with reference to FIG.

  The steps shown in FIGS. 6A to 6C are the same as the steps shown in FIGS. 4A to 4C in the first embodiment, and thus the description thereof is omitted here.

  In the present embodiment, the sealing material 11 is also applied to the radially outer side surface 1b and the radially inner side surface 1c of the power generation cell 1 in the step of FIG. 6D following FIG. 6C. Here, the sealing material 11 applied to the side surfaces 1b and 1c of the power generation cell 1 extends over the anode side and the cathode side (the flow path forming member 3 and the anode electrode layer 5 having the same potential as the cathode electrode layer 6). Therefore, the sealing material 11 has electrical insulation.

  Next, as shown in FIG.6 (e), the cell unit U2 is heated and the sealing material 11 is baked. Since the conditions such as the firing temperature are the same as those of the first embodiment, the description thereof is omitted here.

<Effect>
According to cell unit U2 concerning this embodiment, since it has the same composition as cell unit U1 concerning a 1st embodiment, the same effect as a 1st embodiment can be acquired.

  In the present embodiment, since the sealing material 11 is also applied to the radially outer side surface 1b and the radially inner side surface 1c of the power generation cell 1, the anode electrode layer 5, the cathode electrode layer 6, and the same Insulation with the flow path forming member 3 at an electric potential can be further ensured.

  Further, in the present embodiment, since the sealing material 11 having electrical insulating properties is interposed between the radially outer side surface of the insulating spacer 60 and the radially inner side surface 1c of the power generation cell 1, for example, conductive Even when the composite material of the insulating member and the insulating member is adopted as the insulating spacer 60, the insulation can be surely ensured.

  Of the sealing material 11, the sealing material 11 applied to the side surfaces 1 b and 1 c of the power generation cell 1 is applied to the outer peripheral surface 3 a of the flow path forming member 3 and the upper surface 10 a of the flange 10 of the separator 2. 11 may be different. For example, since the former spans the anode side and the cathode side, it is necessary to have electrical insulation. However, the latter does not span the anode side and the cathode side and therefore has conductivity. May be. Further, in consideration of the surface tension of the sealing material 11, the size of the application range, and the like, it is possible to employ the sealing material 11 having a different viscosity depending on the place to be applied.

<Third Embodiment>
A cell unit U3 that is a solid oxide fuel cell unit according to a third embodiment of the present invention will be described with reference to FIG.

  Similar to the cell unit U2 according to the second embodiment, the cell unit U3 according to the present embodiment includes a power generation cell 1, a separator 2, and a flow path forming member 3 welded to the separator 2. In addition, a sealing material 11 is provided on the side surfaces 1 b and 1 c of the power generation cell 1. As shown in FIG. 7, the cell unit U3 according to the present embodiment is different from the cell unit U2 according to the second embodiment in that the vertical direction of the power generation cell 1 is reversed. That is, in the cell unit U <b> 3, the anode electrode layer 5 of the power generation cell 1 is disposed so as to face the upper surface of the separator 2. The anode electrode layer 5 of the power generation cell 1 is directly joined to the upper surface 10 a of the flange 10 of the separator 2 and the outer peripheral surface 3 a of the flow path forming member 3. The sealing material 11 provided on the side surfaces 1 b and 1 c of the power generation cell 1 extends from the lower surface of the anode electrode layer 5 to the side surface of the electrolyte membrane 4 and covers the side surface of the anode electrode layer 5. Since other configurations are the same as those of the above-described embodiment, the same members are denoted by the same reference numerals and detailed description thereof is omitted. In this embodiment, when power generation is performed, it is a matter of course that the fuel gas is allowed to flow through the intra-unit gas flow path and the oxidant gas is allowed to flow through the inter-unit gas flow path.

  Hereinafter, the manufacturing method of the cell unit U3 concerning this embodiment is demonstrated with reference to FIG.

  The steps shown in FIGS. 8A to 8B are the same as the steps shown in FIGS. 4A to 4B in the first embodiment and FIGS. 6A to 6B in the second embodiment. Since there is, explanation is omitted here.

  In the present embodiment, in the step of FIG. 8C following FIG. 8B, the power generation cell 1 is placed on the sealing material 11, and the power generation cell 1 and the separator unit SU are directly connected (other than the sealing material 11). The cell unit U3 is formed by joining (without interposing any member). In the present embodiment, here, the anode electrode layer 5 is directed downward in the figure, and the anode electrode layer 5 is disposed so as to face the upper surface of the separator 2. Then, the anode electrode layer 5 of the power generation cell 1 is brought into contact with the top surface 10a of the flange 10 of the separator 2 and the top surface 3a of the outer peripheral portion of the flow path forming member 3 while the top of the protrusion 8a of the separator 2 is brought into contact with the anode electrode layer 5. Join directly to.

  Next, in the process of FIG. 8D, the sealing material 11 is also applied to the radially outer side surface 1 b and the radially inner side surface 1 c of the power generation cell 1. The sealing material 11 applied in this step only covers the side surface of the anode electrode layer 5 and the side surface of the electrolyte membrane 4 and does not extend over the anode side and the cathode side. Can be used.

  Next, as shown in FIG.8 (e), the cell unit U3 is heated and the sealing material 11 is baked. Since the conditions such as the firing temperature are the same as those of the first and second embodiments, the description thereof is omitted here.

<Effect>
According to cell unit U3 concerning this embodiment, since it has the same composition as cell units U1 and U2 concerning the 1st and 2nd embodiments, the same effect as these can be acquired.

  Further, according to the present embodiment, the sealing material 11 covers the side surface of the anode electrode layer 5 across the flow path forming member 3 made of metal or the separator 2 to the electrolyte membrane 4 that is a layer made of a dense ceramic material. ing. For this reason, it is possible to reliably prevent the reaction gas in the in-unit gas flow path from leaking into the inter-unit gas flow path through the porous anode electrode layer 5. That is, by adopting the configuration of the present embodiment, the joint surface of the power generation cell 1 with the separator unit SU (the upper surface 10a of the flange 10 of the separator 2 and the upper surface 3a of the outer peripheral portion of the flow path forming member 3 are opposed to these. Even when the surface to be directly joined) is porous, gas sealing properties can be ensured. Thereby, the freedom degree of selection of the power generation cell 1 improves.

<Fourth embodiment>
A cell unit U4 which is a solid oxide fuel cell unit according to a fourth embodiment of the present invention will be described with reference to FIGS.

  Similar to the cell unit U1 according to the first embodiment, the cell unit U4 according to the present embodiment includes the power generation cell 1, the separator 2, and the flow path forming member 3 welded to the separator 2. As shown in FIGS. 9 and 10, the cell unit U4 is further provided with a current collecting auxiliary member 70 interposed between the gas flow path portion 7 of the separator 2 and the power generation region of the power generation cell 1. Different from the cell unit U1 according to the embodiment. In the present embodiment, the current collection auxiliary member 70 is sandwiched between the gas flow path portion 7 of the separator 2 and the power generation cell 1, and the upper surface of the current collection auxiliary member 70 is directly on the lower surface of the cathode electrode layer 6. Surface contact. Since other configurations are the same as those of the above-described embodiment, the same members are denoted by the same reference numerals and detailed description thereof is omitted.

  The current collection auxiliary member 70 is made of a porous body having conductivity and gas permeability, and is formed in an annular plate shape with a circular hole 70a provided in the center. The outer diameter is smaller than the outer diameter of the electrolyte membrane 4 and is substantially equal to the outer diameter of the cathode electrode layer 6 of the power generation cell 1. On the other hand, the inner diameter is larger than the inner diameter of the hole at the center of the electrolyte membrane 4 and is substantially equal to the inner diameter of the cathode electrode layer 6 of the power generation cell 1. As a material for the current collecting auxiliary member 70, it is desirable to use ferritic stainless steel, Inconel (registered trademark), etc., which are excellent in heat resistance. Examples of the porous body that can be used include metal mesh, metal foam, textile fabric made of metal or electrode material, felt, and the like.

  Hereinafter, the manufacturing method of the cell unit U4 according to the present embodiment will be described with reference to FIG.

  Since the process shown in FIG. 11A is the same as the process shown in FIG. 4A in the first embodiment and the process shown in FIG. 6A in the second embodiment, description thereof is omitted here.

  In this embodiment, in the step of FIG. 11B following FIG. 11A, the cell support surface of the separator unit SU (the upper surface 3a of the outer peripheral portion of the flow path forming member 3 and the upper surface 10a of the flange 10 of the separator 2). Then, the sealing material 11 is applied, and the current collecting auxiliary member 70 is placed on the gas flow path portion 7 of the separator 2.

  Next, as shown in FIG. 11 (c), the power generation cell 1 is placed on the applied sealing material 11, and the power generation cell 1 and the separator unit SU are directly interposed (other members other than the sealing material 11 are interposed). Not) to form the cell unit U4. In the present embodiment, the cathode electrode layer 6 is directed downward in the figure, and the current collecting auxiliary member 70 placed on the gas flow path portion 7 of the separator 2 is brought into contact with the cathode electrode layer 6 (direct surface contact). The electrolyte membrane 4 of the power generation cell 1 is directly bonded to the upper surface 10 a of the flange 10 of the separator 2 and the outer peripheral surface 3 a of the flow path forming member 3.

  Next, as shown in FIG.11 (d), the cell unit U4 is heated and the sealing material 11 is baked. Since the conditions such as the firing temperature are the same as those in the above embodiment, the description thereof is omitted here.

<Effect>
According to cell unit U4 concerning this embodiment, since it has the same composition as cell unit U1 concerning a 1st embodiment, the same effect as a 1st embodiment can be acquired.

  Further, in this embodiment, since the current collection auxiliary member 70 is interposed between the gas flow path portion 7 of the separator 2 and the power generation region of the power generation cell 1, the surface direction at the interface between the power generation cell 1 and the separator 2 , And the current density distribution in the cathode electrode layer 6 is leveled. Thereby, the electrical resistance between the power generation cell 1 and the separator 2 can be reduced.

  Metal paste may be applied to both surfaces of the current collection auxiliary member 70. By doing in this way, the contact area of the separator 2 and the electric power generation cell 1 can further be increased, and electrical resistance can be reduced further.

  The current collecting auxiliary member 70 can also be applied to the cell unit U2 according to the second embodiment and the cell unit U3 according to the third embodiment. In this case as well, in the same manner as described above, The effect of reducing the electrical resistance in between can be exhibited.

  As mentioned above, although embodiment of this invention was described, these embodiment is only the illustration described in order to make an understanding of this invention easy, and this invention is not limited to the said embodiment. The technical scope of the present invention is not limited to the specific technical matters disclosed in the above embodiment, but includes various modifications, changes, alternative techniques, and the like that can be easily derived therefrom.

  For example, in the above embodiment, the power generation cell 1 has an annular plate shape, but the shape of the power generation cell 1 is not limited thereto, and may be, for example, an elliptical plate shape or a polygonal plate shape. Further, the power generation cell 1 may be a small-diameter disk or a fan shape, and a plurality of power generation cells 1 may be joined to one separator unit SU.

  Further, the pattern of the gas flow path in the unit and the gas flow path between the units is not limited to those in the above embodiment, and the number and arrangement of the gas passage holes 32 and the through passages 33 of the flow path forming member 3 and the separator 2 It can be set freely by changing the waveform pattern formed in the gas flow path section 7. For example, in the gas channel portion of the separator, two header channel portions extending in the circumferential direction at the inner peripheral portion and the outer peripheral portion, and a plurality of ridges and recesses extending radially in the radial direction are formed, and the circumferential direction A flow path may be configured from two header flow paths that extend in the direction and a plurality of gas flow paths that connect them in the radial direction.

  Furthermore, the flow path forming member 3 may be any member that is welded to the separator 2 to form the in-unit gas flow path or the inter-unit gas flow path, and its shape, arrangement, and number are not limited to those of the above embodiment. . For example, the flow path forming member 3 may be composed of a plurality of members (including those in which a plurality of members are integrally combined and those separated from each other on the separator).

  Moreover, in the said embodiment, although the paste-form sealing material 11 was used for joining between the electric power generation cell 1 and the cell support surface of separator unit SU, a sealing material is not limited to this, A fibrous form, a thin plate form, a ring A molded sealing material molded into a gasket shape or the like may be used.

U1, U2, U3, U4 Cell unit (solid oxide fuel cell unit)
1 Power generation cell 4 Electrolyte membrane 5 Anode electrode layer (anode electrode)
6 Cathode electrode layer (cathode electrode)
SU Separator unit 2 Separator 10 Flange 10a Flange upper surface (cell support surface)
3 Flow path forming member 3a Upper surface of outer peripheral portion (cell support surface)
11 Sealing material 70 Current collecting auxiliary member

Claims (2)

A method for producing a solid oxide fuel cell unit comprising a separator, a flow path forming member, and a power generation cell,
After forming the separator unit by welding the separator and the flow path forming member to each other,
A sealing material is provided on the cell support surface of the separator unit,
A power generation cell is placed on the sealing material,
The separator unit and the power generation cell are directly bonded by heating the sealing material together with the separator unit and the power generation cell and firing the sealing material, thereby producing a solid oxide fuel cell unit . A separator unit formed by welding the separator and the flow path forming member to each other;
A sealing material provided on a cell support surface of the separator unit;
A power generation cell supported by the separator unit via the sealing material,
The solid oxide fuel cell unit, wherein the separator unit and the power generation cell are directly joined by heating the sealing material together with the separator unit and the power generation cell and firing the sealing material.

Images