JP2018133312A - Electrochemical reaction cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain occurrence of gas leak from the position of a seal member.SOLUTION: An electrochemical reaction cell stack includes a flow path connection member including a flange and a tubular part. Two first through holes into which a fastening member, for fastening the flow path connection member to a flat plate member, is inserted, and one second through hole facing the flow path through hole of the flat plate member, are formed in the flange. In the first direction view, center point of the second through hole is located at a position different from a specific median point, that is the median point of a specific segment connecting the center points of the two first through holes. The electrochemical reaction cell stack further includes a seal member placed between the flange and the flat plate member, and surrounding the second through hole, and an elastic member placed between the flange and the flat plate member, and in the first direction view, located in a region on the opposite side to the center point of the second through hole, for at least one of the specific segment and the perpendicular bisector thereof.SELECTED DRAWING: Figure 8

Description

  The technology disclosed herein relates to an electrochemical reaction cell stack.

  One type of fuel cell that generates electricity using an electrochemical reaction between hydrogen and oxygen is a solid oxide fuel cell (hereinafter referred to as “SOFC”) having an electrolyte layer containing a solid oxide. It has been. A fuel cell single cell (hereinafter simply referred to as “single cell”), which is a constituent unit of SOFC, has an electrolyte layer and air facing each other in a predetermined direction (hereinafter referred to as “first direction”) across the electrolyte layer. Electrode and fuel electrode.

  The SOFC generally includes a plurality of single cells arranged side by side in a first direction, and a flat plate member (hereinafter referred to as an “end plate”) disposed on one side of the first direction with respect to the plurality of single cells. In the form of a fuel cell stack. In the fuel cell stack, an air chamber facing the air electrode of each single cell or a plurality of gas flow paths (hereinafter referred to as “manifolds”) communicating with the fuel chamber facing the fuel electrode are formed. Each manifold is used for supplying reaction gas (oxidant gas or fuel gas) to each single cell and discharging off-gas from each single cell.

  In order to connect each manifold to each gas pipe for supplying a reactive gas and discharging off-gas, a through-hole for a flow path communicating with each manifold is formed in the end plate. In addition, a flow path connecting member is provided on the opposite side of the end plate from the plurality of single cells (the one side in the first direction). The flow path connecting member has a flat plate-like flange portion substantially parallel to the end plate, and a tubular tubular portion extending from the flange portion. In the flange portion, a flow path through hole is formed at a position facing the flow path through hole formed in the end plate. The tubular portion constitutes a gas flow path communicating with the flow path through hole of the flange portion. Each of the gas pipes is connected to the tubular portion of the flow path connecting member and formed in the gas flow path constituted by the tubular portion, the flow path through hole formed in the flange portion of the flow path connecting member, and the end plate The manifolds communicate with each manifold through the flow passage through holes. Between the flange portion of the flow path connecting member and the end plate, there is a seal member that surrounds the through hole for the flow path formed in the flange portion of the flow path connecting member in the first direction view in order to prevent gas leakage. Has been placed.

  In addition, a plurality of fastening member through holes are formed in the flange portion of the flow path connecting member, and the flow path connecting member ends by fastening members (for example, bolts) inserted into the through holes for each fastening member. Fastened to the plate (see, for example, Patent Document 1). Moreover, the sealing member mentioned above is pinched | interposed into the flange part and end plate of a flow-path connection member, and is compressed with the fastening force of a fastening member, and, thereby, a sealing member exhibits a gas seal function.

JP 2010-55995 A

  In order to sufficiently exert the gas sealing function of the seal member surrounding the flow path through hole in the flange portion of the flow path connection member, the compressive stress at each position of the seal member is substantially equal and the compressive stress is excessively small. It is desirable that the location does not exist. For example, when two through holes for fastening members are provided in the flange portion of the flow path connecting member, the center of the action point of the fastening force of the two fastening members is the center point of the two through holes for the fastening members It is located at the midpoint (hereinafter referred to as “specific midpoint”) connecting line segments (hereinafter referred to as “specific line segments”). Therefore, in such a case, a configuration in which the center point of the flow path through hole in the flange portion matches the specific midpoint is ideal.

  However, the above ideal configuration may not always be adopted due to restrictions such as the shape of each part of the fuel cell stack and the connection position of each gas pipe. In such a case, the difference in the compressive stress at each position of the seal member becomes large, and there is a possibility that gas leak performance is deteriorated at a portion where the compressive stress is excessive, and gas leak occurs.

 In addition, such a subject is an electrolysis provided with a plurality of electrolytic single cells which are constituent units of a solid oxide electrolytic cell (hereinafter also referred to as “SOEC”) that generates hydrogen using an electrolysis reaction of water. This is a common issue for cell stacks. In this specification, the fuel cell stack and the electrolytic cell stack are collectively referred to as an electrochemical reaction cell stack. Such a problem is not limited to SOFC and SOEC, but is common to other types of electrochemical reaction cell stacks.

  In this specification, the technique which can solve the subject mentioned above is disclosed.

  The technology disclosed in the present specification can be realized as, for example, the following forms.

(1) An electrochemical reaction cell stack disclosed in the present specification includes an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction with the electrolyte layer interposed therebetween, and the electrochemical reaction cell stack in the first direction. A plurality of electrochemical reaction single cells arranged, and a flat plate member disposed on one side in the first direction with respect to the plurality of electrochemical reaction single cells and having a through hole for a flow path formed therein. A gas flow path that communicates with an air chamber facing the air electrode of each electrochemical reaction unit cell or a fuel chamber facing the fuel electrode and that communicates with the through hole for the flow path of the flat plate member In the electrochemical reaction cell stack in which the flat plate member is further formed, the flow path connecting member is disposed on the one side in the first direction with respect to the flat plate member, and is a flat plate substantially parallel to the flat plate member. Two first through holes, and A second through-hole facing the flow-path through-hole of the plate-shaped member is formed, and the center point of the second through-hole is the two first through-holes when viewed in the first direction. What is a specific midpoint that is a region between the center points of the two first through holes in a direction parallel to a specific line segment that connects the center points of the through holes and that is the midpoint of the specific line segment? A flow path connecting member comprising: a flange portion located at a different position; and a tubular portion extending from the flange portion and forming a gas flow channel communicating with the second through hole of the flange portion; A fastening member that is inserted into each of the first through holes of the flange portion and fastens the flow path connecting member to the flat plate member; and is disposed between the flange portion and the flat plate member; A seal member surrounding the second through hole in a direction, the flange portion, and the flat plate The two first penetrations in a direction parallel to the specific line segment as viewed in the first direction, having an elastic modulus smaller than that of the flat plate member and the flow path connecting member. A region between the center points of the holes, and a region opposite to the center point of the second through hole with respect to at least one of the specific line segment and the perpendicular bisector of the specific line segment And an elastic member that is positioned. According to this electrochemical reaction cell stack, the presence of the elastic member can suppress the inclination of the flange portion of the flow path connecting member with respect to the flat plate-like member, and accordingly, the bias of the elastic deformation amount at each position of the seal member is reduced. It becomes small and the difference of the compressive stress in each position of a sealing member becomes small, and it can suppress that a gas leak generate | occur | produces from the position of a sealing member.

(2) In the electrochemical reaction cell stack, the center point of the second through hole is located at a position that does not overlap the specific line segment nor the perpendicular bisector of the specific line segment, and the elastic member Is configured to be located in a region opposite to the center point of the second through hole with respect to both the specific line segment and the vertical bisector of the specific line segment in the first direction view. It is good. According to this electrochemical reaction cell stack, the presence of the elastic member can effectively suppress the inclination of the flange portion of the flow path connecting member with respect to the flat plate member, and accordingly, the amount of elastic deformation at each position of the seal member It is possible to effectively suppress the occurrence of gas leak from the position of the seal member by reducing the difference in compressive stress at each position of the seal member.

(3) In the electrochemical reaction cell stack, the elastic member is a point farthest from the specific midpoint and the specific midpoint on the inner peripheral line of the seal member in the first direction view. It is good also as a shape which is larger than the magnitude | size in the direction parallel to a said 1st straight line, and the magnitude | size in the direction orthogonal to the said 1st straight line which overlaps with the 1st straight line which connects 1 end point. . According to the present electrochemical reaction cell stack, the elastic member can suppress the inclination of the flange portion of the flow path connecting member with respect to the flat plate member, while suppressing the area of the elastic member from being excessive, As a result, it can suppress that the compressive stress in a sealing member falls and the sealing function of a sealing member falls.

(4) In the electrochemical reaction cell stack, the point farthest from the specific middle point on the inner peripheral line of the seal member in the first direction view is a first end point, and the outer peripheral line of the elastic member is A point that is farthest from the specific midpoint is a second end point, a first straight line that connects the first end point and the specific midpoint, and a second line that connects the second end point and the specific midpoint. The angle formed by the straight line is a specific angle θ, the distance between the specific midpoint and the first end point is a first distance L1, and the distance between the specific midpoint and the second end point is When the distance is the second distance L2, it may be configured to satisfy the relationship of θ ≦ 10 ° and 0.9 × L1 ≦ L2 ≦ 1.1 × L1. According to the present electrochemical reaction cell stack, the elastic member can effectively suppress the inclination of the flange portion of the flow path connecting member with respect to the flat plate-like member, and as a result, a gas leak is generated from the position of the seal member. It can be effectively suppressed.

(5) In the electrochemical reaction cell stack, when the area of the sealing member is S1 and the area of the elastic member is S2 in the first direction, the relationship of 0.25 × S1 ≦ S2 ≦ S1 It is good also as composition which satisfies. According to the electrochemical reaction cell stack, the elastic member area is prevented from being excessively increased and the sealing function of the sealing member is prevented from being deteriorated, and the elastic member area is secured to a certain extent and the flow path is connected to the flat plate member. The inclination of the flange part of a member can be suppressed.

(6) In the electrochemical reaction cell stack, the electrolyte layer may include a solid oxide. According to this electrochemical reaction cell stack, it is possible to suppress the occurrence of gas leak from the position of the seal member in the electrochemical reaction cell stack that is operated at a relatively high temperature and is likely to cause a gas leak.

  The technology disclosed in the present specification can be realized in various forms. For example, an electrochemical reaction cell stack (a fuel cell stack or an electrolytic cell stack) including a plurality of electrochemical reaction single cells, It can be realized in the form of its manufacturing method.

1 is a perspective view showing an external configuration of a fuel cell stack 100 in the present embodiment. It is explanatory drawing which shows the XZ cross-section structure of the fuel cell stack 100 in the position of II-II of FIG. FIG. 3 is an explanatory diagram showing a YZ cross-sectional configuration of a fuel cell stack 100 at a position of III-III in FIG. 1. It is explanatory drawing which shows XZ cross-section structure of the two electric power generation units 102 adjacent to each other in the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-section structure of the two electric power generation units 102 adjacent to each other in the same position as the cross section shown in FIG. 3 is a perspective view showing an external configuration of a flow path connecting member 27. FIG. FIG. 7 is an explanatory diagram illustrating an XY cross-sectional configuration (a cross-sectional configuration at a position VII-VII in FIG. 2) of the flange portion 28 and the like of the flow path connecting member 27. It is explanatory drawing which shows XY cross-sectional structure (cross-sectional structure of the position of VIII-VIII of FIG. 2), such as the sealing member 220 and the elastic member 230. FIG. It is a XZ side view which shows the structure of the periphery of the flow-path connection member 27 in this embodiment. It is XZ side view which shows the structure of the periphery of the flow-path connection member 27 in a comparative example. It is explanatory drawing which shows XY cross-sectional structure of the sealing member 220 at the time of simulation which concerns on 1st Embodiment, and the elastic member 230 grade | etc.,. It is explanatory drawing which shows XY cross-sectional structure of the sealing member 220 in 2nd Embodiment, the elastic member 230, etc. FIG. It is explanatory drawing which shows XY cross-sectional structure of the sealing member 220 at the time of the simulation which concerns on 2nd Embodiment, and the elastic member 230 grade | etc.,. It is explanatory drawing which shows XY cross-sectional structure of the sealing member 220 in 3rd Embodiment, the elastic member 230, etc. FIG. It is explanatory drawing which shows XY cross-sectional structure of the sealing member 220 in 4th Embodiment, the elastic member 230, etc. FIG.

A. First embodiment:
A-1. Constitution:
(Configuration of fuel cell stack 100)
FIG. 1 is a perspective view showing an external configuration of a fuel cell stack 100 in the present embodiment, and FIG. 2 is an explanatory diagram showing an XZ cross-sectional configuration of the fuel cell stack 100 at a position II-II in FIG. FIG. 3 is an explanatory diagram showing a YZ cross-sectional configuration of the fuel cell stack 100 at the position of III-III in FIG. In each figure, XYZ axes orthogonal to each other for specifying the direction are shown. In this specification, for the sake of convenience, the positive direction of the Z axis is referred to as the upward direction, and the negative direction of the Z axis is referred to as the downward direction. However, the fuel cell stack 100 is actually different from such an orientation. It may be installed. The same applies to FIG.

  The fuel cell stack 100 includes a plurality of (seven in this embodiment) power generation units 102 and a pair of end plates 104 and 106. The seven power generation units 102 are arranged side by side in a predetermined arrangement direction (vertical direction in the present embodiment). The pair of end plates 104 and 106 are arranged so as to sandwich an assembly composed of seven power generation units 102 from above and below. The arrangement direction (vertical direction) corresponds to the first direction in the claims.

  As shown in FIG. 1, holes that penetrate each layer in the vertical direction are formed around the four corners of the outer periphery around the Z direction of each layer (each power generation unit 102, end plates 104, 106) constituting the fuel cell stack 100. The holes corresponding to each other formed in each layer communicate with each other in the vertical direction to form a bolt hole 109 extending in the vertical direction from one end plate 104 to the other end plate 106. Bolts 22 are inserted into the respective bolt holes 109, and the fuel cell stack 100 is fastened by the respective bolts 22 and nuts (not shown).

  Further, as shown in FIGS. 1 to 3, a hole penetrating each power generation unit 102 in the vertical direction is formed near the middle point of the outer periphery around each Z direction of each power generation unit 102. The holes corresponding to each other formed in 102 communicate with each other in the vertical direction to form a communication hole 108 extending in the vertical direction across the plurality of power generation units 102. In the following description, a hole formed in each power generation unit 102 to configure the communication hole 108 may also be referred to as the communication hole 108.

  As shown in FIGS. 1 and 2, the fuel cell stack 100 is located near the midpoint of one side (the X-axis positive direction side of two sides parallel to the Y-axis) on the outer periphery around the Z-direction. The communication hole 108 to which the oxidant gas OG is introduced from the outside of the fuel cell stack 100 and the oxidant gas introduction manifold is a gas flow path for supplying the oxidant gas OG to an air chamber 166 described later of each power generation unit 102. The communication hole 108, which functions as 161, is located near the midpoint of the opposite side (the side on the negative X-axis side of the two sides parallel to the Y-axis). It functions as an oxidant gas discharge manifold 162 that is a gas flow path for discharging the oxidant off-gas OOG that is a gas discharged from the chamber 166 to the outside of the fuel cell stack 100. In the present embodiment, for example, air is used as the oxidant gas OG.

  Further, as shown in FIGS. 1 and 3, the vicinity of the midpoint of one side (the side on the Y axis positive direction side of two sides parallel to the X axis) on the outer periphery of the fuel cell stack 100 around the Z direction A communication hole 108 located in the fuel cell stack 100 receives a fuel gas FG from the outside of the fuel cell stack 100 and supplies a fuel gas FG to a fuel chamber 176 (to be described later) of each power generation unit 102. The communication hole 108 located near the midpoint of the opposite side of the side (the side on the Y axis negative direction side of the two sides parallel to the X axis) is a fuel chamber of each power generation unit 102. It functions as a fuel gas discharge manifold 172 that is a gas flow path for discharging the fuel off-gas FOG that is the gas discharged from 176 to the outside of the fuel cell stack 100. In the present embodiment, as the fuel gas FG, for example, hydrogen-rich gas obtained by reforming city gas is used.

(Configuration of end plates 104 and 106)
The pair of end plates 104 and 106 are substantially rectangular flat plate-shaped conductive members, and are formed of, for example, stainless steel. One end plate 104 is disposed on the upper side of the power generation unit 102 located on the uppermost side, and the other end plate 106 is disposed on the lower side of the power generation unit 102 located on the lowermost side. A plurality of power generation units 102 are held in a pressed state by a pair of end plates 104 and 106. The upper end plate 104 functions as a positive output terminal of the fuel cell stack 100, and the lower end plate 106 functions as a negative output terminal of the fuel cell stack 100. As shown in FIGS. 2 and 3, four passage through holes 107 are formed in the lower end plate 106. The four flow passage through holes 107 communicate with the oxidant gas introduction manifold 161, the oxidant gas discharge manifold 162, the fuel gas introduction manifold 171, and the fuel gas discharge manifold 172, respectively. The lower end plate 106 corresponds to a flat plate member in the claims.

(Configuration of flow path connecting member 27 and the like)
As shown in FIGS. 2 and 3, the fuel cell stack 100 further includes four flow paths arranged on the side opposite to the plurality of power generation units 102 (that is, the lower side) with respect to the lower end plate 106. A connecting member 27 is provided. The four flow path connecting members 27 are respectively arranged at positions that overlap the oxidant gas introduction manifold 161, the oxidant gas discharge manifold 162, the fuel gas introduction manifold 171, and the fuel gas discharge manifold 172 in the vertical direction.

  Each flow path connecting member 27 has a flat plate-like flange portion 28 substantially parallel to the end plate 106 and a tubular tubular portion 29 extending from the flange portion 28. In the flange portion 28, a flow path through hole 202 is formed at a position facing the flow path through hole 107 formed in the end plate 106. In the present embodiment, the shape of the flow path through hole 202 when viewed in the vertical direction is substantially circular. In addition, the tubular portion 29 constitutes the gas flow path 26 that communicates with the flow path through hole 202 of the flange portion 28. Each gas pipe (not shown) for supplying reactive gas and discharging off-gas is connected to the tubular portion 29 of the flow passage connecting member 27, and is connected to the gas flow passage 26 and the flange portion 28 constituted by the tubular portion 29. The manifolds 161, 162, 171, and 172 are communicated with each other through the formed flow passage through holes 202 and the flow passage through holes 107 formed in the end plate 106. In addition, between the flange part 28 of each flow path connection member 27 and the end plate 106, in order to prevent a gas leak, the seal member which surrounds the flow-path through-hole 202 formed in the flange part 28 in the vertical direction view. 220 is arranged. The seal member 220 is made of mica, for example. In the present embodiment, the shape of the seal member 220 when viewed in the vertical direction is a substantially annular shape. The configuration around the flow path connection member 27 in the fuel cell stack 100 will be described in detail later. The flow path through hole 202 formed in the flange portion 28 of the flow path connection member 27 corresponds to the second through hole in the claims.

(Configuration of power generation unit 102)
4 is an explanatory diagram showing an XZ cross-sectional configuration of two power generation units 102 adjacent to each other at the same position as the cross section shown in FIG. 2, and FIG. 5 is adjacent to each other at the same position as the cross section shown in FIG. It is explanatory drawing which shows the YZ cross-section structure of the two electric power generation units. As shown in FIGS. 4 and 5, each power generation unit 102 includes a unit cell 110, a separator 120, an air electrode side frame 130, an air electrode side current collector 134, a fuel electrode side frame 140, and a fuel electrode. A side current collector 144 and a pair of interconnectors 150 constituting the uppermost layer and the lowermost layer of the power generation unit 102 are provided. In the separator 120, the air electrode side frame 130, the fuel electrode side frame 140, and the interconnector 150, there are holes corresponding to the communication holes 108 constituting the manifolds 161, 162, 171, and 172 described above in the Z direction. Is formed.

  The interconnector 150 is a substantially rectangular flat plate-shaped conductive member, and is formed of, for example, ferritic stainless steel. The interconnector 150 ensures electrical continuity between the power generation units 102 and prevents reaction gas from being mixed between the power generation units 102. In the present embodiment, when two power generation units 102 are arranged adjacent to each other, one interconnector 150 is shared by two adjacent power generation units 102. That is, the upper interconnector 150 in a power generation unit 102 is the same member as the lower interconnector 150 in another power generation unit 102 adjacent to the upper side of the power generation unit 102. Further, since the fuel cell stack 100 includes the pair of end plates 104 and 106, the power generation unit 102 located at the top in the fuel cell stack 100 does not include the upper interconnector 150 and is located at the bottom. The power generation unit 102 does not include the lower interconnector 150 (see FIGS. 2 and 3).

  The unit cell 110 includes an electrolyte layer 112, and an air electrode (cathode) 114 and a fuel electrode (anode) 116 that face each other in the vertical direction (the arrangement direction in which the power generation units 102 are arranged) with the electrolyte layer 112 interposed therebetween. The single cell 110 of the present embodiment is a fuel electrode-supported single cell that supports the electrolyte layer 112 and the air electrode 114 with the fuel electrode 116.

  The electrolyte layer 112 is a substantially rectangular flat plate-shaped member. For example, YSZ (yttria stabilized zirconia), ScSZ (scandia stabilized zirconia), SDC (samarium doped ceria), GDC (gadolinium doped ceria), perovskite oxide It is formed with solid oxides such as. The air electrode 114 is a substantially rectangular flat plate-shaped member, and is formed of, for example, a perovskite oxide (for example, LSCF (lanthanum strontium cobalt iron oxide), LSM (lanthanum strontium manganese oxide), LNF (lanthanum nickel iron)). Has been. The fuel electrode 116 is a substantially rectangular flat plate-like member, and is formed of, for example, Ni (nickel), cermet made of Ni and ceramic particles, Ni-based alloy, or the like. Thus, the single cell 110 (power generation unit 102) of the present embodiment is a solid oxide fuel cell (SOFC) that uses a solid oxide as an electrolyte.

  The separator 120 is a frame-like member in which a substantially rectangular hole 121 penetrating in the vertical direction is formed near the center, and is made of, for example, metal. The peripheral part of the hole 121 in the separator 120 is opposed to the peripheral part of the surface of the electrolyte layer 112 on the air electrode 114 side. The separator 120 is bonded to the single cell 110 by a bonding portion 124 formed of a brazing material (for example, Ag brazing) disposed in the facing portion. The separator 120 divides the air chamber 166 facing the air electrode 114 and the fuel chamber 176 facing the fuel electrode 116, and gas leaks from one electrode side to the other electrode side in the peripheral portion of the single cell 110. It is suppressed.

 The air electrode side frame 130 is a frame-like member in which a substantially rectangular hole 131 penetrating in the vertical direction is formed near the center, and is formed of an insulator such as mica, for example. The hole 131 of the air electrode side frame 130 forms an air chamber 166 that faces the air electrode 114. The air electrode side frame 130 is in contact with the peripheral edge portion of the surface of the separator 120 opposite to the side facing the electrolyte layer 112 and the peripheral edge portion of the surface of the interconnector 150 facing the air electrode 114. . The pair of interconnectors 150 included in the power generation unit 102 is electrically insulated by the air electrode side frame 130. The air electrode side frame 130 has an oxidant gas supply communication hole 132 communicating the oxidant gas introduction manifold 161 and the air chamber 166, and an oxidant gas communicating the air chamber 166 and the oxidant gas discharge manifold 162. A discharge communication hole 133 is formed.

  The fuel electrode side frame 140 is a frame-like member in which a substantially rectangular hole 141 penetrating in the vertical direction is formed near the center, and is made of, for example, metal. The hole 141 of the fuel electrode side frame 140 forms a fuel chamber 176 that faces the fuel electrode 116. The fuel electrode side frame 140 is in contact with the peripheral portion of the surface of the separator 120 facing the electrolyte layer 112 and the peripheral portion of the surface of the interconnector 150 facing the fuel electrode 116. Further, the fuel electrode side frame 140 has a fuel gas supply communication hole 142 that connects the fuel gas introduction manifold 171 and the fuel chamber 176, and a fuel gas discharge communication hole 143 that connects the fuel chamber 176 and the fuel gas discharge manifold 172. And are formed.

  The fuel electrode side current collector 144 is disposed in the fuel chamber 176. The fuel electrode side current collector 144 includes an interconnector facing portion 146, an electrode facing portion 145, and a connecting portion 147 that connects the electrode facing portion 145 and the interconnector facing portion 146. For example, nickel or a nickel alloy It is made of stainless steel or the like. The electrode facing portion 145 is in contact with the surface of the fuel electrode 116 on the side opposite to the side facing the electrolyte layer 112, and the interconnector facing portion 146 is on the surface of the interconnector 150 on the side facing the fuel electrode 116. In contact. However, as described above, since the lowermost power generation unit 102 in the fuel cell stack 100 does not include the lower interconnector 150, the interconnector facing portion 146 in the power generation unit 102 has a lower end plate. 106 is in contact. Since the fuel electrode side current collector 144 has such a configuration, the fuel electrode 116 and the interconnector 150 (or the end plate 106) are electrically connected. Note that a spacer 149 made of, for example, mica is disposed between the electrode facing portion 145 and the interconnector facing portion 146. Therefore, the fuel electrode side current collector 144 follows the deformation of the power generation unit 102 due to the temperature cycle and the reaction gas pressure fluctuation, and the fuel electrode 116 and the interconnector 150 (or the end plate 106) via the fuel electrode side current collector 144. The electrical connection with is maintained well.

  The air electrode side current collector 134 is disposed in the air chamber 166. The air electrode side current collector 134 is composed of a plurality of current collector elements 135 having a substantially quadrangular prism shape, and is formed of, for example, ferritic stainless steel. The air electrode side current collector 134 is in contact with the surface of the air electrode 114 opposite to the side facing the electrolyte layer 112 and the surface of the interconnector 150 facing the air electrode 114. However, as described above, since the power generation unit 102 located at the top in the fuel cell stack 100 does not include the upper interconnector 150, the air electrode side current collector 134 in the power generation unit 102 includes the upper end plate. 104 is in contact. Since the air electrode side current collector 134 has such a configuration, the air electrode 114 and the interconnector 150 (or the end plate 104) are electrically connected. In the present embodiment, the air electrode side current collector 134 and the interconnector 150 are formed as an integral member. That is, a flat plate portion perpendicular to the vertical direction (Z-axis direction) of the integrated member functions as the interconnector 150 and is formed so as to protrude from the flat plate portion toward the air electrode 114. The current collector element 135 that is a plurality of convex portions functions as the air electrode side current collector 134. Moreover, the integral member of the air electrode side current collector 134 and the interconnector 150 may be covered with a conductive coat, and between the air electrode 114 and the air electrode side current collector 134, A conductive bonding layer to be bonded may be interposed.

A-2. Operation of the fuel cell stack 100:
As shown in FIGS. 2 and 4, the oxidant gas OG is supplied via a gas pipe (not shown) connected to the tubular portion 29 of the flow path connection member 27 provided at the position of the oxidant gas introduction manifold 161. When supplied, the oxidant gas OG is oxidized through the gas flow path 26 constituted by the tubular portion 29, the flow path through hole 202 of the flange portion 28, and the flow path through hole 107 of the end plate 106. The oxidant gas introduction manifold 161 is supplied, and the oxidant gas introduction manifold 161 is supplied to the air chamber 166 through the oxidant gas supply communication hole 132 of each power generation unit 102. As shown in FIGS. 3 and 5, the fuel gas FG is supplied via a gas pipe (not shown) connected to the tubular portion 29 of the flow path connecting member 27 provided at the position of the fuel gas introduction manifold 171. When supplied, the fuel gas FG passes through the gas flow path 26 formed by the tubular portion 29, the flow path through hole 202 of the flange portion 28, and the flow path through hole 107 of the end plate 106. The fuel is supplied to the introduction manifold 171 and supplied from the fuel gas introduction manifold 171 to the fuel chamber 176 via the fuel gas supply communication hole 142 of each power generation unit 102.

  When the oxidant gas OG is supplied to the air chamber 166 of each power generation unit 102 and the fuel gas FG is supplied to the fuel chamber 176, power is generated by an electrochemical reaction between the oxidant gas OG and the fuel gas FG in the single cell 110. Is called. This power generation reaction is an exothermic reaction. In each power generation unit 102, the air electrode 114 of the single cell 110 is electrically connected to one interconnector 150 via the air electrode side current collector 134, and the fuel electrode 116 is connected via the fuel electrode side current collector 144. The other interconnector 150 is electrically connected. The plurality of power generation units 102 included in the fuel cell stack 100 are electrically connected in series. Therefore, electrical energy generated in each power generation unit 102 is taken out from the end plates 104 and 106 that function as output terminals of the fuel cell stack 100. Since SOFC generates power at a relatively high temperature (for example, 700 ° C. to 1000 ° C.), the fuel cell stack 100 is heated by a heater (after the start-up until the high temperature can be maintained by the heat generated by the power generation. (Not shown).

  The oxidant off-gas OOG discharged from the air chamber 166 of each power generation unit 102 is discharged to the oxidant gas discharge manifold 162 via the oxidant gas discharge communication hole 133 as shown in FIGS. The gas flow path 26 constituted by the flow path through hole 107 of the plate 106, the flow path through hole 202 of the flange portion 28 of the flow path connection member 27 provided at the position of the oxidant gas discharge manifold 162, and the tubular portion 29. Then, the gas is discharged to a gas pipe (not shown) connected to the tubular portion 29. Further, as shown in FIGS. 3 and 5, the fuel off-gas FOG discharged from the fuel chamber 176 of each power generation unit 102 is discharged to the fuel gas discharge manifold 172 via the fuel gas discharge communication hole 143, and further to the end plate. 106, through the flow passage through hole 107 of the flow passage connecting member 27 provided at the position of the fuel gas discharge manifold 172, the flow passage through hole 202 of the flange portion 28 of the flow passage connecting member 27, and the gas flow passage 26 constituted by the tubular portion 29. The gas pipe (not shown) connected to the tubular portion 29 is discharged.

A-3. Detailed configuration around the flow path connecting member 27:
Next, a detailed configuration around the flow path connecting member 27 in the fuel cell stack 100 of the present embodiment will be described. 6 is a perspective view showing an external configuration of the flow path connecting member 27, and FIG. 7 is an XY cross-sectional configuration of the flange portion 28 and the like of the flow path connecting member 27 (a cross-sectional configuration at the position VII-VII in FIG. 2). FIG. 8 is an explanatory diagram showing an XY cross-sectional configuration (cross-sectional configuration at a position of VIII-VIII in FIG. 2) of the seal member 220 and an elastic member 230 described later. In FIG. 7 and FIG. 8, in order to clarify the positional relationship of each part, the position of each part that does not appear in the cross section is indicated by a broken line.

  As described above, the flow path connecting member 27 includes the flange portion 28 and the tubular portion 29. In the present embodiment, the shape of the flange portion 28 when viewed in the vertical direction is a substantially rectangular shape. As shown in FIGS. 6 to 8, in addition to the flow path through hole 202, two fastening member through holes 201 are formed in the flange portion 28 of the flow path connection member 27. In the present embodiment, the two fastening member through holes 201 are arranged so as to be aligned with each other in the Y direction. Each fastening member through hole 201 formed in the flange portion 28 of the flow path connecting member 27 corresponds to the first through hole in the claims.

  A fastening member 210 (for example, a bolt) is inserted into each through hole 201 for fastening member. The channel connecting member 27 is fastened to the end plate 106 by the fastening member 210 inserted into each fastening member through hole 201. Further, due to the fastening force of the fastening member 210, the seal member 220 surrounding the flow path through hole 202 of the flange portion 28 is sandwiched between the flange portion 28 and the end plate 106 and compressed, whereby the seal member 220 is gas sealed. Demonstrate the function.

  As shown in FIGS. 7 and 8, in the present embodiment, the center point CP of the flow passage through hole 202 formed in the flange portion 28 of the flow passage connection member 27 is the center of the two fastening member through holes 201. It is located at a position different from the midpoint (hereinafter referred to as “specific midpoint MP”) connecting the line segments (hereinafter referred to as “specific line segment SS”). More specifically, the center point CP of the flow path through hole 202 is located at a position that does not overlap the specific line segment SS nor the vertical bisector SN of the specific line segment SS.

  Here, in order to fully exhibit the gas sealing function of the seal member 220 disposed so as to surround the flow path through hole 202 of the flange portion 28 of the flow path connection member 27, compression at each position of the seal member 220 is performed. It is desirable that there is no portion where the stress is substantially uniform and the compressive stress is excessively small. If the compressive stress at a specific location on the seal member 220 is too small, gas may leak from the location. In the case where the two fastening member through holes 201 are provided in the flange portion 28 as in the present embodiment, the center of the point of action of the fastening force by the two fastening members 210 is located at the specific midpoint MP described above. To do. Therefore, if the configuration is such that the center point CP of the flow path through hole 202 coincides with the specific midpoint MP, the compressive stress at each position of the seal member 220 formed so as to surround the flow path through hole 202 is increased. Since it becomes substantially equal, generation | occurrence | production of the gas leak from the position of the sealing member 220 is suppressed. However, for example, due to restrictions such as the shape of each part of the fuel cell stack 100 and the connection position of each gas pipe, the center point CP of the flow path through hole 202 is different from the specific midpoint MP as in the present embodiment. In some cases, it may be necessary to adopt a configuration located in the area.

  In the fuel cell stack 100 of the present embodiment, an elastic member 230 is disposed between the flange portion 28 of the flow path connection member 27 and the end plate 106 in order to suppress the occurrence of gas leak even in such a configuration. Yes. The elastic member 230 has a smaller elastic modulus than the end plate 106 and the flange portion 28 of the flow path connecting member 27. That is, the elastic member 230 is a member that is relatively easily deformed. The elastic member 230 is made of, for example, mica. Note that the shape of the elastic member 230 when viewed in the vertical direction is, for example, a substantially circular shape.

  As shown in FIGS. 7 and 8, the elastic member 230 is positioned in a region R1 between the center points of the two fastening member through holes 201 in the direction parallel to the specific line segment SS (Y direction) when viewed in the vertical direction. To do. Further, the elastic member 230 is located in a region opposite to the center point CP of the flow path through hole 202 with respect to both the specific line segment SS and the vertical bisector SN of the specific line segment SS. That is, in the present embodiment, the center point CP of the flow path through-hole 202 is located on the X axis positive direction side with respect to the specific line segment SS, and with respect to the vertical bisector SN of the specific line segment SS. Since the elastic member 230 is positioned on the Y axis negative direction side, the elastic member 230 is positioned on the X axis negative direction side with respect to the specific line segment SS, and with respect to the vertical bisector SN of the specific line segment SS. It is located on the Y axis positive direction side. In this specification, the phrase “the elastic member 230 is located in a specific area” means that at least a part of the elastic member 230 is located in the specific area.

  Since the fuel cell stack 100 of the present embodiment includes the elastic member 230 having such a configuration, the occurrence of gas leak from the position of the seal member 220 can be suppressed as described below. FIG. 9 is an XZ side view showing a configuration around the flow path connecting member 27 in this embodiment, and FIG. 10 is an XZ side view showing a configuration around the flow path connecting member 27 in the comparative example. The comparative example shown in FIG. 10 is different from the present embodiment shown in FIG. 9 in that the elastic member 230 is not disposed between the flange portion 28 of the flow path connecting member 27 and the end plate 106.

  In this embodiment (and comparative example), as shown in FIGS. 7 and 8, the center point CP of the flow path through hole 202 formed in the flange portion 28 of the flow path connection member 27 is the specific line segment SS. It is located at a position different from the specific midpoint MP. More specifically, the center point CP of the flow path through hole 202 is located at a position that does not overlap the specific line segment SS nor the vertical bisector SN of the specific line segment SS. In such a configuration, as in the comparative example shown in FIG. 10, if the elastic member 230 does not exist, the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106 is caused by the fastening force of the two fastening members 210. Along with this, the deviation of the amount of elastic deformation at each position of the seal member 220 is increased, the difference in compressive stress at each position of the seal member 220 is increased, and a portion where the compressive stress is excessively small (for example, in FIG. In the X1 portion shown), the gas sealability may be reduced and gas leakage may occur.

  In contrast, in the present embodiment, the elastic member 230 is disposed between the flange portion 28 of the flow path connecting member 27 and the end plate 106. In addition, the elastic member 230 is located in the region R1 between the center points of the two fastening member through holes 201 in the direction parallel to the specific line segment SS (Y direction) when viewed in the vertical direction, and the specific line segment SS It is located in a region on the opposite side of the center point CP of the flow-through hole 202 with respect to both the vertical bisector SN of the specific line segment SS. Therefore, as shown in FIG. 9, the presence of the elastic member 230 suppresses the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106, and accordingly, the elastic deformation amount at each position of the seal member 220 is biased. It becomes small, the difference of the compressive stress in each position of the sealing member 220 becomes small, and it can suppress that gas leak generate | occur | produces from the position of the sealing member 220. FIG.

As shown in FIGS. 7 and 8, the point farthest from the specific middle point MP on the inner peripheral line of the seal member 220 in the vertical direction is defined as the first end point P1, and the specific point on the outer peripheral line of the elastic member 230 is specified. A point farthest from the midpoint MP is taken as a second end point P2, a first straight line SL1 connecting the first end point P1 and the specific midpoint MP, and a second line connecting the second end point P2 and the specific midpoint MP. The angle between the straight line SL2 and the second straight line SL2 is a specific angle θ, the distance between the specific midpoint MP and the first end point P1 is a first distance L1, and the specific midpoint MP and the second end point P2 are When the distance between them is the second distance L2,
θ ≦ 10 ° (1)
And 0.9 × L1 ≦ L2 ≦ 1.1 × L1 (2)
It is preferable to satisfy the relationship. That is, it is preferable that the first straight line SL1 and the second straight line SL2 are substantially parallel, and the first distance L1 and the second distance L2 are substantially the same. If the elastic member 230 and the like are configured to satisfy the relational expressions (1) and (2), the elastic member 230 can effectively suppress the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106. As a result, the occurrence of gas leak from the position of the seal member 220 can be effectively suppressed. In the example shown in FIGS. 7 and 8, the specific angle θ = 0 ° (that is, the first straight line SL1 and the second straight line SL2 are parallel), and the first distance L1 is equal to the first distance L1. The distance L2 of 2 is equal to each other.

Further, when the area of the seal member 220 is S1 and the area of the elastic member 230 is S2 in the vertical direction view,
0.25 × S1 ≦ S2 ≦ S1 (3)
It is preferable to satisfy the relationship. That is, it is preferable that the area S2 of the elastic member 230 is ¼ or more of the area S1 of the seal member 220 and not more than the area S1 of the seal member 220. If the area S2 of the elastic member 230 is excessive, the compressive force acting on the seal member 220 is reduced by the increase in the compressive force acting on the elastic member 230, and the sealing function of the seal member 220 is lowered. If the area S2 of the elastic member 230 is too small, the elastic member 230 cannot effectively suppress the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106. If the elastic member 230 or the like is configured so as to satisfy the above relational expression (3), the area of the elastic member 230 is suppressed while suppressing the area S2 of the elastic member 230 from becoming excessive and the sealing function of the seal member 220 from being lowered. The inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106 can be suppressed by securing S2 to some extent.

A simulation was performed on the sealing performance of the seal member 220, and the compressive stress at each position of the seal member 220 was calculated. In the present embodiment (see FIGS. 7 to 9) in which the elastic member 230 is disposed (see Condition 1 below for the detailed configuration of the elastic member 230), the compressive stress at each position of the seal member 220 is 9 to 10 MPa. It was. On the other hand, in the comparative example (see FIG. 10) in which the elastic member 230 is not disposed, the compressive stress at each position of the seal member 220 is 7 to 11 MPa. That is, in the present embodiment in which the elastic member 230 is disposed, the minimum value of the compressive stress of the seal member 220 is increased by about 30% from 7 MPa to 9 MPa as compared with the comparative example in which the elastic member 230 is not disposed. In this simulation, in order to prevent deformation of the flange portion 28, as shown in FIG. 11, an elasticity surrounding each fastening member through hole 201 between the flange portion 28 of the flow path connecting member 27 and the end plate 106. A member 222 (for example, mica) was disposed. From this simulation result, when the elastic member 230 having the above-described configuration is arranged, the difference in the compressive stress at each position of the seal member 220 is reduced, the portion where the compressive stress is too small is eliminated, and gas leaks from the position of the seal member 220. It was confirmed that generation | occurrence | production can be suppressed.
<Condition 1>
・ Θ = 0 °
・ L1 = L2
・ S2 = 0.25 × S1

B. Second embodiment:
FIG. 12 is an explanatory diagram showing an XY cross-sectional configuration of the seal member 220, the elastic member 230, and the like according to the second embodiment. Hereinafter, among the configurations of the second embodiment, the same configurations as those of the first embodiment (see FIG. 8 and the like) described above are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  As shown in FIG. 12, in the second embodiment, the shape of the elastic member 230 in the vertical direction is different from that of the first embodiment described above. That is, the shape of the elastic member 230 in the vertical direction is substantially circular in the first embodiment, but is substantially rectangular in the second embodiment. More specifically, in the fourth embodiment, the shape of the elastic member 230 in the vertical direction view has a size W1 in a direction orthogonal to the first straight line SL1 connecting the first end point P1 and the specific middle point MP. The shape is larger than the size W2 in the direction parallel to the first straight line SL1. Note that the elastic member 230 has a shape and an arrangement so as to overlap with the first straight line SL1 when viewed in the vertical direction.

  In 2nd Embodiment, in addition to the effect | action and effect of 1st Embodiment mentioned above, there exist the following effects. That is, in the second embodiment, the elastic member 230 has a shape in which the size W1 in the direction orthogonal to the first straight line SL1 is larger than the size W2 in the direction parallel to the first straight line SL1, and thus the elastic member 230. The size W1 in the direction orthogonal to the first straight line SL1 can be increased while suppressing an increase in the area S2. If the area S2 of the elastic member 230 is large, the compressive force acting on the seal member 220 is lowered by the amount of the compressive force acting on the elastic member 230, and the sealing function of the seal member 220 is lowered. Moreover, when the size W1 of the elastic member 230 in the direction orthogonal to the first straight line SL1 is large, the elastic member 230 can effectively suppress the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106. it can. Therefore, according to the second embodiment, the elastic member 230 effectively suppresses the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106, and suppresses the area S2 of the elastic member 230 from becoming excessive. As a result, it is possible to suppress the compressive stress in the seal member 220 from being lowered and the sealing function of the seal member 220 from being lowered. In addition, since the elastic member 230 exists on the inside of the circular arc of radius L2 centering on the specific midpoint MP or inside this circular arc, it can suppress effectively that the sealing function of the sealing member 220 falls, preferable.

  Also in the second embodiment, it is preferable that the elastic member 230 and the like are configured to satisfy the relational expressions (1) to (3). In the example shown in FIG. 12, the specific angle θ = 10 °, and the first distance L1 and the second distance L2 are equal to each other.

A simulation was performed on the sealing performance of the seal member 220, and the compressive stress at each position of the seal member 220 was calculated. In the second embodiment (see FIG. 12) in which the elastic member 230 is disposed (see conditions 2 and 3 below for the detailed configuration of the elastic member 230), the compressive stress at each position of the seal member 220 is 8.8 to 10 MPa (condition 2) or 8.4 to 9.9 MPa (condition 3). On the other hand, as described above, in the comparative example in which the elastic member 230 is not disposed (see FIG. 10), the compressive stress at each position of the seal member 220 is 7 to 11 MPa. That is, in the second embodiment in which the elastic member 230 is disposed, the minimum value of the compressive stress of the seal member 220 is increased by about 20% from 7 MPa to 8.4 MPa as compared with the comparative example in which the elastic member 230 is not disposed. did. In this simulation, in order to prevent deformation of the flange portion 28, as shown in FIG. 13, the elasticity surrounding the through hole 201 for each fastening member is provided between the flange portion 28 of the flow path connecting member 27 and the end plate 106. A member 222 (for example, mica) was disposed. From this simulation result, when the elastic member 230 having the above-described configuration is arranged, the difference in the compressive stress at each position of the seal member 220 is reduced, the portion where the compressive stress is too small is eliminated, and gas leaks from the position of the seal member 220. It was confirmed that generation | occurrence | production can be suppressed. In particular, it has been confirmed that the elastic member 230 and the like are preferably configured to satisfy the relational expressions (1) to (3).
<Condition 2>
・ Θ = 10 °
・ L2 = 1.1 × L1
・ S2 = 0.5 × S1
<Condition 3>
・ Θ = 10 °
・ L2 = 0.9 × L1
・ S2 = 0.5 × S1

C. Third embodiment:
FIG. 14 is an explanatory diagram showing XY cross-sectional configurations of the seal member 220, the elastic member 230, and the like according to the third embodiment. Hereinafter, among the configurations of the third embodiment, the same configurations as those of the first embodiment (see FIG. 8 and the like) described above are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  As shown in FIG. 14, in the third embodiment, the position of the center point CP of the flow path through hole 202 formed in the flange portion 28 of the flow path connection member 27 is different from that of the first embodiment described above. Specifically, in the third embodiment, the center point CP of the flow path through hole 202 is the midpoint (specific line segment SS) connecting the center points of the two fastening member through holes 201 (specific line segment SS). Although it is a position different from the midpoint MP), it is located on the specific line segment SS.

  As in the configuration of the third embodiment, even when the center point CP of the flow path through hole 202 is on the specific line segment SS, the center point CP is different from the specific midpoint MP of the specific line segment SS. Similarly to the first embodiment described above, when the elastic member 230 is not present, the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106 is increased by the fastening force of the fastening member 210, and each of the seal members 220. The bias of the elastic deformation amount at the position becomes large, the difference in compressive stress at each position of the seal member 220 becomes large, and there is a possibility that the gas sealing performance is deteriorated at a place where the compressive stress is excessive and gas leak occurs.

  However, also in the configuration of the third embodiment, the elastic member 230 is disposed between the flange portion 28 of the flow path connecting member 27 and the end plate 106 as in the first embodiment described above. In addition, the elastic member 230 is located in the region R1 between the center points of the two fastening member through holes 201 in the direction parallel to the specific line segment SS (Y direction) when viewed in the vertical direction, and the elastic member 230 includes the specific line segment SS. It is located in a region opposite to the center point CP of the flow path through hole 202 with respect to the vertical bisector SN. That is, in the third embodiment, since the center point CP of the flow path through hole 202 is located on the Y-axis negative direction side with respect to the vertical bisector SN of the specific line segment SS, the elastic member 230 is , Located on the Y axis positive direction side with respect to the vertical bisector SN of the specific line segment SS. Therefore, the presence of the elastic member 230 suppresses the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106, and the bias of the elastic deformation amount at each position of the seal member 220 is reduced, so that the position at each position of the seal member 220 is reduced. The difference in compressive stress is reduced, and the occurrence of gas leak from the position of the seal member 220 can be suppressed.

  Also in the third embodiment, it is preferable that the elastic member 230 and the like are configured so as to satisfy the relational expressions (1) to (3). In the example shown in FIG. 14, the specific angle θ = 0 ° (that is, the first straight line SL1 and the second straight line SL2 are parallel), and the first distance L1 and the second distance L2 Are equal to each other.

D. Fourth embodiment:
FIG. 15 is an explanatory diagram showing an XY cross-sectional configuration of the seal member 220 and the elastic member 230 in the fourth embodiment. Hereinafter, among the configurations of the fourth embodiment, the same configurations as those of the first embodiment (see FIG. 8 and the like) described above are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  As shown in FIG. 15, in the fourth embodiment, the position of the center point CP of the flow path through hole 202 formed in the flange portion 28 of the flow path connection member 27 is different from that of the first embodiment described above. Specifically, in the fourth embodiment, the center point CP of the flow path through hole 202 is the midpoint (specific line segment) of the line segment (specific line segment SS) connecting the center points of the two fastening member through holes 201. Although it is different from the midpoint MP), it is located on the vertical bisector SN of the specific line segment SS.

  As in the configuration of the fourth embodiment, even if the center point CP of the flow path through hole 202 is on the vertical bisector SN of the specific line segment SS, what is the specific midpoint MP of the specific line segment SS? In the case of different positions, as in the first embodiment described above, if the elastic member 230 is not present, the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106 is large due to the fastening force by the fastening member 210. Therefore, the bias of the elastic deformation amount at each position of the seal member 220 is increased, and the difference in the compressive stress at each position of the seal member 220 is increased. May occur.

  However, also in the configuration of the fourth embodiment, the elastic member 230 is disposed between the flange portion 28 of the flow path connecting member 27 and the end plate 106 as in the first embodiment described above. In addition, the elastic member 230 is located in the region R1 between the center points of the two fastening member through holes 201 in the direction parallel to the specific line segment SS (Y direction) when viewed in the vertical direction, and the specific member SS On the other hand, it is located in a region opposite to the center point CP of the flow path through hole 202. That is, in the fourth embodiment, since the center point CP of the flow path through-hole 202 is located on the X axis positive direction side with respect to the specific line segment SS, the elastic member 230 is located with respect to the specific line segment SS. And is located on the X axis negative direction side. Therefore, the presence of the elastic member 230 suppresses the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106, and the bias of the elastic deformation amount at each position of the seal member 220 is reduced, so that the position at each position of the seal member 220 is reduced. The difference in compressive stress is reduced, and the occurrence of gas leak from the position of the seal member 220 can be suppressed.

  Also in the fourth embodiment, it is preferable that the elastic member 230 and the like are configured to satisfy the relational expressions (1) to (3). In the example shown in FIG. 15, the specific angle θ = 0 ° (that is, the first straight line SL1 and the second straight line SL2 are parallel), and the first distance L1 and the second distance L2 Are equal to each other.

E. Variations:
The technology disclosed in the present specification is not limited to the above-described embodiment, and can be modified into various forms without departing from the gist thereof. For example, the following modifications are possible.

  The configuration of the single cell 110 or the fuel cell stack 100 in the above embodiment is merely an example, and various modifications can be made. For example, the center point CP of the flow-through hole 202 is different from the specific midpoint MP of the specific line segment SS, and the specific line segment SS is also a vertical bisector SN of the specific line segment SS. In the first and second embodiments, which are located at positions that do not overlap, the elastic member 230 flows to both the specific line segment SS and the vertical bisector SN of the specific line segment SS in the vertical direction. It is assumed that the elastic member 230 is located between the specific line segment SS and the vertical bisector SN of the specific line segment SS when viewed in the vertical direction. It may be located in a region on the opposite side to the center point CP of the flow passage through hole 202 with respect to at least one. For example, in the first embodiment, the elastic member 230 is a region opposite to the center point CP of the flow passage through-hole 202 with respect to the vertical bisector SN of the specific line segment SS. The minute SS may be located in a region on the same side as the center point CP of the flow path through hole 202. Even in such a configuration, the presence of the elastic member 230 can suppress the inclination of the flange portion 28 of the flow path connecting member 27 with respect to the end plate 106, and the difference in compressive stress at each position of the seal member 220 can be reduced. Thus, the occurrence of gas leak from the position of the seal member 220 can be suppressed.

  In each of the above embodiments, a part or all of the relational expressions (1) to (3) may not be satisfied.

  Further, in each of the above embodiments, the shape of the elastic member 230 in the vertical direction is not limited to a circle or a rectangle, and can be deformed to an arbitrary shape. Similarly, the shape of the flow path through-hole 202, the fastening member through-hole 201, the seal member 220, the flange portion 28, and the like as viewed in the up-down direction can be changed to an arbitrary shape.

  Further, in each of the above embodiments, it is not necessary to employ the configuration including the elastic member 230 described above around all the flow path connecting members 27 provided in the fuel cell stack 100, and at least one flow path connecting member. About the periphery of 27, the structure provided with the elastic member 230 grade | etc., Mentioned above should just be employ | adopted.

  In each of the above embodiments, the number of unit cells 110 included in the fuel cell stack 100 is merely an example, and the number of unit cells 110 is appropriately determined according to the output voltage required for the fuel cell stack 100 or the like. . Moreover, the material which comprises each member in each said embodiment is an illustration to the last, and each member may be comprised with the other material.

  Further, in each of the above embodiments, the SOFC that generates power using the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidant gas is targeted. Similarly, the present invention can be applied to an electrolytic unit cell that is a constituent unit of a solid oxide electrolytic cell (SOEC) that generates hydrogen by using hydrogen, and an electrolytic cell stack including a plurality of electrolytic unit cells. The configuration of the electrolytic cell stack is well known as described in, for example, Japanese Patent Application Laid-Open No. 2006-81813, and thus will not be described in detail here. However, the configuration is generally the same as that of the fuel cell stack 100 in the above-described embodiment. It is a configuration. That is, the fuel cell stack 100 in the above-described embodiment may be read as an electrolytic cell stack, the power generation unit 102 may be read as an electrolytic cell unit, and the single cell 110 may be read as an electrolytic single cell. However, when the electrolysis cell stack is operated, a voltage is applied between the two electrodes so that the air electrode 114 is positive (anode) and the fuel electrode 116 is negative (cathode). Water vapor as a source gas is supplied. As a result, an electrolysis reaction of water occurs in each electrolysis cell unit, hydrogen gas is generated in the fuel chamber 176, and hydrogen is taken out of the electrolysis cell stack through the communication hole. Also in the electrolytic single cell and the electrolytic cell stack having such a configuration, the elastic member 230 having the above-described configuration is disposed between the flange portion 28 of the flow path connecting member 27 and the end plate 106 as in the above embodiments. Then, it is possible to suppress the occurrence of gas leak from the position of the seal member 220.

 In the above embodiment, the solid oxide fuel cell (SOFC) has been described as an example. However, the present invention is applicable to other types of fuel cells (or electrolytic cells) such as a molten carbonate fuel cell (MCFC). Applicable.

22: Bolt 26: Gas flow path 27: Flow path connection member 28: Flange part 29: Tubular part 100: Fuel cell stack 102: Power generation unit 104: End plate 106: End plate 107: Through hole for flow path 108: Communication hole 109: Bolt hole 110: Single cell 112: Electrolyte layer 114: Air electrode 116: Fuel electrode 120: Separator 121: Hole 124: Joint part 130: Air electrode side frame 131: Hole 132: Oxidant gas supply communication hole 133: Oxidation Agent gas discharge communication hole 134: Air electrode side current collector 135: Current collector element 140: Fuel electrode side frame 141: Hole 142: Fuel gas supply communication hole 143: Fuel gas discharge communication hole 144: Fuel electrode side current collector 145: Electrode facing portion 146: Interconnector facing portion 147: Connection portion 149: Spacer 150: interconnector 161: oxidant gas introduction manifold 162: oxidant gas discharge manifold 166: air chamber 171: fuel gas introduction manifold 172: fuel gas discharge manifold 176: fuel chamber 201: through hole for fastening member 202: for flow path Through-hole 210: Fastening member 220: Seal member 222: Elastic member 230: Elastic member

Claims (7)

A plurality of electrochemical reaction unit cells arranged in the first direction, each including an electrolyte layer and an air electrode and a fuel electrode facing each other in a first direction across the electrolyte layer;
A plate-like member that is disposed on one side of the first direction with respect to the plurality of electrochemical reaction single cells, and in which a through-hole for a flow path is formed;
With
A gas flow path is formed which communicates with the air chamber facing the air electrode of each electrochemical reaction unit cell or the fuel chamber facing the fuel electrode and with the flow path through hole of the flat plate member. In an electrochemical reaction cell stack,
A flow path connecting member disposed on the one side in the first direction with respect to the flat plate member,
A flat plate shape substantially parallel to the flat plate member, two first through holes and one second through hole facing the flow channel through hole of the flat plate member are formed; The center of the two first through holes in a direction parallel to a specific line segment connecting the center points of the two first through holes when viewed from the first direction. A flange portion that is an area between points and is located at a position different from the specific midpoint that is the midpoint of the specific line segment;
A tubular portion extending from the flange portion and constituting a gas flow path communicating with the second through hole of the flange portion;
A flow path connecting member comprising:
A fastening member that is inserted into each first through hole of the flange portion and fastens the flow path connecting member to the flat plate member;
A seal member disposed between the flange portion and the flat plate member and surrounding the second through hole in the first direction view;
The elastic member is disposed between the flange portion and the flat plate member and has a smaller elastic modulus than the flat plate member and the flow path connecting member, and in a direction parallel to the specific line segment in the first direction view. A region between the center points of the two first through holes, and the center point of the second through hole with respect to at least one of the specific line segment and the perpendicular bisector of the specific line segment An elastic member located in a region opposite to
An electrochemical reaction cell stack comprising: The electrochemical reaction cell stack according to claim 1,
The center point of the second through hole is located at a position not overlapping the specific line segment nor the perpendicular bisector of the specific line segment,
The elastic member is in a region opposite to the center point of the second through-hole with respect to both the specific line segment and a vertical bisector of the specific line segment in the first direction view. An electrochemical reaction cell stack, characterized by being located. The electrochemical reaction cell stack according to claim 2,
The elastic member has a first straight line that connects the specific midpoint and a first end point that is the farthest from the specific midpoint on the inner circumference of the seal member in the first direction view. The electrochemical reaction cell stack is characterized in that a size in a direction perpendicular to the first straight line is larger than a size in a direction parallel to the first straight line. In the electrochemical reaction cell stack according to any one of claims 1 to 3,
In the first direction view,
A point that is farthest from the specific middle point on the inner circumference of the seal member is a first end point,
A point farthest from the specific middle point on the outer peripheral line of the elastic member is a second end point,
An angle formed by a first straight line connecting the first end point and the specific midpoint and a second straight line connecting the second end point and the specific midpoint is defined as a specific angle θ.
When the distance between the specific midpoint and the first end point is a first distance L1, and the distance between the specific midpoint and the second end point is a second distance L2,
θ ≦ 10 °
And 0.9 × L1 ≦ L2 ≦ 1.1 × L1
An electrochemical reaction cell stack characterized by satisfying the relationship In the electrochemical reaction cell stack according to any one of claims 1 to 4,
In the first direction view,
The area of the sealing member is S1,
When the area of the elastic member is S2,
0.25 × S1 ≦ S2 ≦ S1
An electrochemical reaction cell stack characterized by satisfying the relationship In the electrochemical reaction cell stack according to any one of claims 1 to 5,
The electrochemical reaction cell stack, wherein the electrolyte layer includes a solid oxide. In the electrochemical reaction stack according to any one of claims 1 to 6,
The electrochemical reaction cell stack, wherein the electrochemical reaction single cell is a fuel cell single cell.

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