JP2016167373A - Fuel battery stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery stack that can reduce the voltage loss at the projection portion of a collector plate and enhance the performance of the fuel battery stack.SOLUTION: In a fuel battery stack 1, a midpoint M in the width W of a second projection portion 15 exists within a belt-like range (that is, connectable range SKH) between a first contact line L1 contacting the outer periphery of one through-hole 10c of a collector plate 9 and a second contact line L2 contacting the outer periphery of the other through-hole 10d. Thus, the flow of power (current) generated in the fuel battery stack 1 is difficult to be hindered by the through-hole 10, so that power can be easily supplied from the collector portion 65 of the collector plate 9 via the second projection portion 15 to the second output terminal 16. Therefore, the voltage loss is reduced, and the performance of the fuel battery stack 1 can be enhanced.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a fuel cell stack including a plurality of unit cells each having a solid electrolyte and an air electrode and a fuel electrode.

Conventionally, as a fuel cell, for example, a solid oxide fuel cell (SOFC) using a solid electrolyte (solid oxide) is known.
In this solid oxide fuel cell, for example, a flat plate-shaped fuel electrode is provided on one side of a flat solid electrolyte, and a flat plate-shaped oxidation electrode is in contact with an oxidant gas (for example, air) on the other side. A flat plate type fuel cell single cell provided with an agent electrode (air electrode) is used.

Furthermore, in recent years, in order to obtain a desired voltage, a fuel cell stack in which a plurality of fuel cell single cells are stacked via an interconnector and a current collector has been developed.
In this type of fuel cell stack, a structure is proposed in which electric end plates are arranged at both ends in the stacking direction of a single unit of the fuel cell, and the electric power is extracted by using the end plates as the positive and negative electrodes of the fuel cell stack. Has been.

  As such a power take-out structure of the fuel cell stack, the output member is brought into surface contact with a fastening bolt that fastens each member constituting the fuel cell stack, and the power is taken out, and the end plate is integrated at the position of the fastening bolt. It is disclosed that electric power is taken out by the output member (see Patent Document 1).

  Separately from this, in order to prevent short circuit between the fuel cell stack and various auxiliary devices (BOP), the laminated part (stack body) such as a single unit of the fuel cell and the end plate are electrically insulated. The technique to do is proposed (refer patent document 2).

  In this technique, an insulating plate made of mica or the like is disposed between the stack body and the end plate so as to be electrically insulated. Moreover, in order to take out electric power from a stack main body, the current collecting plate has been arrange | positioned inside the insulating plate (stack main body side). Further, the current collector plate is provided with a protruding portion that protrudes from the side surface of the fuel cell stack to the outer peripheral side in order to connect to the external output terminal.

JP 2011-76890 A International Publication No. 2006/009277

However, in the above-described conventional technology, the structure for extracting power is not sufficiently studied, and voltage loss may occur when power is extracted to the outside.
That is, depending on the structure for taking out the electric power, the voltage loss may increase, and in this case, there is a problem that the performance of the fuel cell stack deteriorates.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a fuel cell stack capable of reducing the voltage loss at the protruding portion of the current collector plate and enhancing the performance of the fuel cell stack. And

  (1) According to a first aspect of the present invention, a power generation unit including a fuel cell single cell having a fuel electrode, an air electrode, and a solid electrolyte, and electric power generated by the fuel cell single cell via a current collector A fuel cell stack, wherein a plurality of the power generation units are continuously arranged, and the current collector plates are arranged in a first direction in which the power generation units are continuous. When viewed from one direction, the current collector plate includes a current collector disposed in a region where the power generation units overlap, and a protrusion protruding from the current collector, wherein the current collector is A current collecting area in which the current collector is disposed, and a plurality of through holes disposed on an outer periphery of the current collecting area including first and second through holes adjacent to each other, and the first The first through hole intersects perpendicularly to a line segment connecting the centroid of the through hole and the centroid of the second through hole. A midpoint in the width of the protruding portion exists between a first tangent line that touches the outer periphery and a second tangent line that intersects the line segment perpendicularly and touches the outer periphery of the second through-hole, The width is a length of the projecting portion in a direction perpendicular to a projecting direction parallel to either the first tangent line or the second tangent line.

  In the first aspect, the current collecting portion of the current collecting plate includes a current collecting area where the current collector is disposed, and a plurality of through holes including the first through hole and the second through hole adjacent to each other around the current collecting area. Holes (that is, a plurality of through holes arranged on the outer periphery of the current collecting area).

  Further, the first tangent line that intersects the line segment connecting the centroid of the first through hole and the centroid of the second through hole perpendicularly and contacts the outer periphery of the first through hole intersects the line segment perpendicularly. A midpoint in the width of the projecting portion exists between the second tangent line and the second tangent line that contacts the outer periphery of the second through hole. The width of the protrusion is the length of the protrusion in a direction perpendicular to the protrusion direction parallel to either the first tangent line or the second tangent line.

  That is, in the first aspect, the midpoint in the width of the protruding portion is a band shape between the first tangent line that contacts the outer periphery of the first through hole and the second tangent line that contacts the outer periphery of the second through hole. (That is, a connectable range described later). That is, the current flow between the current collection area and the protrusion is set so as not to be hindered by the through hole.

  As described above, in the first aspect, the power (and thus the current) generated in the fuel cell stack is not easily blocked by the through holes, and thus is efficiently supplied from the current collecting area of the current collecting plate to the protruding portion. Is done. Therefore, there is a remarkable effect that the voltage loss is small and the performance of the fuel cell stack is improved.

  Moreover, since the protrusion part which has the midpoint set as mentioned above can be comprised compactly, there exists an advantage that the heat sink from the part (for example, stack main body) by which the electric power generation unit is arrange | positioned continuously can be suppressed.

  Note that the condition regarding the position of the midpoint is preferably satisfied in the entire range of the projecting portion. However, the condition of the first embodiment (that is, the midpoint is in the connectable range for at least one midpoint. It is sufficient that the above condition is satisfied.

  (2) In the second aspect of the present invention, when viewed from the first direction, the protruding portion has a width on the root side that is larger than the tip side in the protruding direction. Here, the root side means the current collecting area side compared to the tip side.

  In the second aspect, since the width of the protruding portion is larger on the base side than the distal end side in the protruding direction, current easily flows from the current collecting portion to the protruding portion. Further, there is an advantage that the strength on the base side of the protruding portion is large and is hardly damaged.

(3) In the third aspect of the present invention, when viewed from the first direction, the width of the projecting portion gradually increases toward the root side.
In the third aspect, since the width of the protruding portion gradually increases toward the root side, the current easily flows from the current collecting portion to the protruding portion. Moreover, there is an advantage that the strength on the base side of the protruding portion is larger and it is more difficult to break.

<Next, each configuration of the fuel cell stack of the present invention will be described>
The centroid means the center of gravity (area center) in a plane figure.
-As the material of the current collector plate, stainless steel, nickel, nickel alloy, etc. can be adopted.

The fuel cell unit cell and the power generation unit are not particularly limited as long as they can be stacked (that is, arranged so as to overlap each other) such as a flat plate shape or a flat shape.
The power generation unit is a basic unit that generates power using a single fuel cell. As the power generation unit, in addition to the single fuel cell, a configuration for extracting power from the single fuel cell (for example, an air electrode current collector, a fuel electrode current collector, an interconnector, etc.) The thing provided with the member etc. which prescribe | regulate a path | route is mentioned.

  -As a current collection area, when the current collector is a single body, the projection area of the current collector when viewed from the first direction can be mentioned. In addition, when there are a plurality of current collectors, a range that surrounds the outer periphery of the projection area of each current collector when viewed from the first direction can be given. For example, there is a range in which the projection areas of all the current collectors are bound from the outer periphery with strings.

-As a range where a through-hole is arrange | positioned, the range (namely, frame-shaped outer periphery part of a current collector plate) which surrounds the outer periphery of a current collection area, for example is mentioned.
-Fuel gas and oxidant gas are mentioned as a raw material in generating electric power with a fuel cell stack. The fuel gas indicates a gas containing a reducing agent (for example, hydrogen) serving as a fuel, and the oxidant gas indicates a gas (for example, air) containing an oxidant (for example, oxygen).

  ・ When power generation is performed using a fuel cell stack, a fuel gas is introduced to the fuel electrode side and an oxidant gas is introduced to the air electrode side.

1 is a perspective view of a fuel cell stack of Example 1. FIG. FIG. 2 is a cross-sectional view schematically showing a part of the fuel cell stack of Example 1 disassembled and broken in the stacking direction. 2 is an exploded perspective view showing a power generation unit of the fuel cell stack of Example 1. FIG. It is a top view which shows the surface in which the air electrode electrical power collector of the interconnector of Example 1 was formed. It is a perspective view which expands and shows the anode current collector of Example 1, and its principal part. 3 is a plan view showing a current collector plate of Example 1. FIG. FIG. 6 is an explanatory diagram illustrating, in plan view, the definition of the width and the like of a second protrusion in a part of the current collector plate of Example 1. (A) is a top view which shows the 1st end plate of Example 1, (b) is explanatory drawing which shows prescription | regulations, such as the width | variety of the 1st protrusion part provided in the 1st end plate. (A) is a top view which shows a part of collector plate of Example 2, (b) is a top view which shows a part of the modification. (A) is a top view which shows a part of collector plate of Example 3, (b) is a top view which shows a part of the modification. It is sectional drawing which decomposes | disassembles a part of fuel cell stack of Example 4, and fractures | ruptures in the lamination direction, and is shown typically. (A) is a front view which shows the protrusion part (2nd protrusion part) of one collector plate in a part of fuel cell stack of Example 5, (b) is the other collector plate in the modification. It is a front view which shows a protrusion part (1st protrusion part). 6 is a perspective view showing a fuel cell stack of Example 6. FIG. FIG. 20 is an explanatory diagram illustrating, in plan view, the definition of the width and the like of a second protrusion in a part of the current collector plate of Example 6. FIG. 10 is a perspective view showing a fuel cell stack of Example 7. FIG. 10 is an explanatory diagram illustrating, in plan view, the definition of the width and the like of a second protrusion in a part of the current collector plate of Example 8. It is a perspective view which decomposes | disassembles some other fuel cell stacks, and shows typically.

  Hereinafter, a solid oxide fuel cell stack will be described as an example of a fuel cell stack to which the present invention is applied.

a) First, the schematic configuration of the fuel cell stack according to the first embodiment will be described.
As shown in FIG. 1, a solid oxide fuel cell stack (hereinafter simply referred to as “fuel cell stack”) 1 of the first embodiment includes a fuel gas (for example, hydrogen) and an oxidant gas (for example, air. It is a device that generates electricity by being supplied with oxygen in the air.

  In the drawings, the oxidant gas is indicated by “O”, and the fuel gas is indicated by “F”. “IN” indicates that gas is introduced, and “OUT” indicates that gas is discharged. In the fuel cell stack 1, “up and down” indicates the vertical direction in FIGS. 1 and 2 for convenience, and does not determine the directionality of the fuel cell stack 1.

  The fuel cell stack 1 according to the first embodiment includes a first end plate 3 and a second end plate 5 disposed at both ends (that is, both upper and lower ends) in the vertical direction (stacking direction: first direction) in FIG. This is a fuel cell stack in which a plurality of flat plate-like (for example, 20 stages) power generation units 7 and current collector plates 9 described later are laminated.

  A plurality of (for example, eight) through-holes 10 are provided in the end plates 3 and 5 at both the upper and lower ends, the power generation units 7 and the current collecting plates 9 in order to penetrate them in the stacking direction. Both end plates 3, each bolt 11 a, 11 b, 11 c, 11 d, 11 e, 11 f, 11 g, 11 h (collectively referred to as 11) and each nut 12 screwed into each bolt 11, 5, each power generation unit 7, current collector plate 9, and the like are integrally fixed via an insulator 8 (see FIG. 12).

  In addition, the specific (four) bolts 11b, 11d, 11f, and 11h among the bolts 11 have an internal flow path 14 through which an oxidant gas or a fuel gas flows along the axial direction (vertical direction in FIG. 1). Is formed. The bolt 11b is used for discharging fuel gas, the bolt 11d is used for discharging oxidant gas, the bolt 11f is used for introducing fuel gas, and the bolt 11h is used for introducing oxidant gas.

  And in order to take out electric power from the fuel cell stack 1, the 1st protrusion part 13 is formed in the upper 1st end plate 3, and the 2nd current collector plate 9 has the 2nd as it explains in full detail later. A protruding portion 15 is formed.

Hereinafter, the portion where the power generation units 7 are stacked is referred to as a stack body 20.
b) Next, the configuration of the power generation unit 7 and the like will be described in detail.
2 to 5, the vertical and horizontal dimensions are set as appropriate so that the configuration of the fuel cell stack 1 can be easily understood, and the number of members and the like are also set as appropriate.

  As schematically shown in FIGS. 2 and 3, the power generation unit 7 is an interconnector 19a, 19b (generally referred to as 19) or the like on both sides of the fuel cell single cell 17 in the thickness direction (vertical direction in FIG. 2). It is equipped with. The configuration of the power generation unit 7 on the second end plate 5 side (the lower end side in FIG. 2) of the fuel cell stack 1 is slightly different from the other power generation units 7, and will be described in detail later.

  Specifically, each power generation unit 7 other than the lower end includes a metal interconnector 19a, an air electrode insulating frame 23, a metal separator 25, a metal fuel electrode frame 27, a metal interconnector 19b, and the like. Are laminated. In the fuel cell stack 1, the adjacent power generation units 7 share the interconnector 19 disposed therebetween. In addition, each of the stacked members 19, 23 to 27 is formed with each through hole 10 through which each bolt 11 is inserted.

  Among these, the fuel cell single cell 17 is joined to the separator 25 as described later. A convex air electrode current collector 33 (see FIG. 2) integral with the interconnector 19 is disposed in a flow path (air flow path through which oxidizing gas flows) 31 in the frame of the air electrode insulating frame 23. . A fuel electrode current collector 37 is disposed in a flow path (fuel flow path through which fuel gas flows) 35 in the frame of the fuel electrode frame 27.

Hereinafter, each configuration will be described in more detail.
<Interconnector 19>
The interconnector 19 is made of a conductive plate material (for example, a metal plate such as stainless steel such as SUS430). The interconnector 19 ensures conduction between the fuel cell single cells 17 and prevents gas mixing between the fuel cell single cells 17 (and thus between the power generation units 7). In addition, the interconnector 19 should just be arrange | positioned when arrange | positioning between the adjacent fuel cell single cells 17. FIG.

  As shown in FIG. 4, the interconnector 19 is formed on a plate-like portion 41, which is a square plate member, and one surface of the plate-like portion 41, specifically, a surface facing the air electrode 55 (see FIG. 2). And a large number of air electrode current collectors 33.

The air electrode current collectors 33 have a block shape (a rectangular parallelepiped shape), and are arranged in a plurality of rows vertically and horizontally in a lattice shape so as to protrude from the plate-like portion 41 toward the air electrode 55.
<Air electrode insulation frame 23>
Returning to FIG. 3, the air electrode insulating frame 23 is a square frame-like plate material having electrical insulation, and is a mica frame made of soft mica. The air electrode insulating frame 23 is formed with a rectangular opening 23 a constituting the air flow path 31 at the center thereof (in a plan view as viewed from the thickness direction).

  Further, in the air electrode insulating frame 23, the long side communication holes 43 d are respectively connected to the frame portions on each side where the pair of opposing through holes 10 (10 d, 10 h) are provided so as to communicate with the respective through holes 10. , 43h are provided. Further, the air electrode insulating frame 23 is provided with a plurality of grooves 47d and 47h as portions (communication portions) through which air passes so as to communicate the communication holes 45d and 45h with the opening 23a.

<Separator 25>
The separator 25 is a rectangular frame-like conductive plate material (for example, a metal plate such as stainless steel such as SUS430). The outer peripheral edge (upper surface) of the single fuel cell 17 is brazed and joined to the separator 25 at the inner peripheral edge (lower surface) along the square opening 25a at the center. That is, the fuel cell single cell 17 is joined so as to close the opening 25 a of the separator 25.

<Fuel electrode frame 27>
The fuel electrode frame 27 is a rectangular frame-shaped plate material made of, for example, stainless steel such as SUS430 having conductivity. The fuel electrode frame 27 is formed with a rectangular opening 27a constituting the fuel flow path 35 at the center (in plan view).

  Further, in the fuel electrode frame 27, the pair of opposing through holes 10 (10b, 10f) are elongated holes, and the respective communicating holes 57b, 57f are provided so as to communicate the elongated holes with the opening 27a. ing.

<Fuel electrode current collector 37>
As shown in FIG. 5, the anode current collector 37 is a combination of a spacer 61 that is a core material made of mica and a metal conductive plate (for example, a flat foil made of nickel) 63 that is a conductive member. It is a well-known lattice-like member (for example, refer to the current collecting member 19 described in JP2013-55042A).

  Specifically, the fuel electrode current collector 37 includes a spacer (ladder mica) 61 in which a number of long holes 61a are opened in parallel, and a conductive plate in which each joining piece 63a of the conductive plate 63 is bent and attached to the spacer 61. 63.

<Fuel cell single cell 17>
Returning to FIG. 2, the fuel cell single cell 17 has a so-called fuel electrode support membrane type structure, which is a thin-film solid electrolyte (solid electrolyte layer) 51 and one side thereof (downward in FIG. 2). A formed fuel electrode (anode) 53 and a thin film air electrode (cathode) 55 formed on the other side (upper side in FIG. 2) are integrally laminated.

  Further, since the separator 25 is joined to the upper surface of the outer peripheral edge portion of the solid electrolyte layer 51, the air flow is prevented by the separator 25 so that the oxidant gas and the fuel gas are not mixed inside the power generation unit 7. The passage 31 and the fuel passage 35 are separated.

  In addition, the air flow path 31 is provided in the air electrode 55 side of the fuel cell single cell 17, the fuel flow path 35 is provided in the fuel electrode 53 side, and the flow direction of the air in the air flow path 31 is shown in FIG. It is the left-right direction, and the direction in which the fuel gas flows in the fuel flow path 35 is a direction perpendicular to the paper surface.

Here, the structure of the single fuel cell 17 will be described in more detail.
The air electrode 55 is a porous layer through which an oxidant gas can pass.
Examples of the material constituting the air electrode 55 include metals, metal oxides, and metal composite oxides. Examples of the metal include metals such as Pt, Au, Ag, Pd, Ir, Ru, and alloys thereof. Examples of the metal oxide include oxides such as La, Sr, Ce, Co, Mn, and Fe, such as La ₂ O ₃ , SrO, Ce ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , and FeO.

As the composite oxide, composite oxides containing La, Pr, Sm, Sr, Ba, Co, Fe, Mn, etc. (La _1-x Sr _x CoO ₃ -based composite oxide, La _1-x Sr _x FeO ₃₎ system composite _{oxide, La 1-x Sr x Co} 1-y Fe y O 3 composite _{oxide, La 1-x Sr x MnO} 3 composite _{oxide, Pr 1-x Ba x CoO} 3 composite oxide, Sm _1-x Sr _x CoO ₃ composite oxide) or the like can be used.

  The solid electrolyte layer 51 is a dense layer made of a solid oxide, and can move the oxidant gas (oxygen) introduced into the air electrode 55 as ions during operation (power generation) of the fuel cell stack 1. It has ionic conductivity.

  Examples of the material constituting the solid electrolyte layer 51 include zirconia-based, ceria-based, and perovskite-based electrolyte materials. Examples of zirconia-based materials include yttria stabilized zirconia (YSZ), scandia stabilized zirconia (ScSZ), and calcia stabilized zirconia (CaSZ), and yttria stabilized zirconia (YSZ) is generally used. There are many examples. For ceria-based materials, so-called rare earth element-added ceria is used, and for perovskite-based materials, perovskite-type double oxides containing lanthanum elements are used.

The fuel electrode 53 is a porous layer through which fuel gas can pass.
Examples of the material constituting the fuel electrode 53 include ZrO ₂ ceramics such as zirconia and CeO ceramics stabilized by at least one of metals such as Ni and Fe and rare earth elements such as Sc and Y. And mixtures with ceramics. Further, a metal such as Ni, or a cermet or Ni-based alloy of Ni and the ceramic can be used.

c) Next, a configuration for taking out electric power from the fuel cell stack 1 at the end of the fuel cell stack 1 in the stacking direction will be described.
<Configuration on the second end plate 5 side>
As shown in FIG. 2, in the power generation unit 7 at the lowest stage of the fuel cell stack 1, instead of the above-described interconnector 19 b so as to contact the lower surfaces of the fuel electrode frame 27 and the fuel electrode current collector 37, a current collector is provided. A plate 9 is arranged.

Further, an end insulating plate 64 is stacked below the current collector plate 9, and a second end plate 5 is stacked below the end insulating plate 64.
Of these, the end insulating plate 64 is made of mica similar to the air electrode insulating frame 23, and is a flat plate material having the same outer peripheral shape as the interconnector 19 in plan view. The second end plate 5 is a member having the same shape made of the same material as that of the first end plate 3.

  Further, as shown in FIG. 6, the current collector plate 9 described above includes a current collector 65 having the same shape (square shape) as the planar shape of the stack body 20, and the outer periphery of the current collector 65 (hence, the stack body 20 in plan view). And a second protrusion 15 protruding outward. The current collector plate 9 is made of the same material as the interconnector 19.

  Of the current collector 65, the rectangular frame-shaped edge 69 constituting the outer periphery has eight through-holes 10 through which the bolts 11 are inserted at equal intervals, similarly to the other fuel electrode frame 27 and the like. Is formed.

  That is, the current collector 65 is arranged in a region where the power generation units 7 overlap in a plan view, and is a rectangular current collector in which the fuel electrode current collector 37 is arranged inside the edge 69 of the current collector 65. An electric area 70 (shaded area in FIG. 6) is formed.

  Further, the second projecting portion 15 extends from the outer periphery of the edge portion 69 where a pair of adjacent through holes 10 (for example, the through holes 10c and 10d) are arranged in a portion corresponding to one side (right side) of the edge portion 69. It is formed so as to protrude outward. That is, the second projecting portion 15 is formed so as to project outward from the right side of the outer periphery of the edge portion 69 between the through holes 10c and 10d perpendicularly to the right side.

  A protrusion through hole 71 may be formed on the distal end side of the second protrusion 15. Further, the second output terminal 16 may be connected to the second projecting portion 15 in order to extract electric power to the outside.

In particular, in the first embodiment, the configuration of the second projecting portion 15 is set as shown in FIG.
Specifically, among the adjacent through holes 10, the line SB is perpendicular to the line segment SB connecting the centroid of one through hole (first through hole) 10 c and the centroid of the other through hole (second through hole) 10 d. Between the first tangent line L1 that intersects the outer periphery of one through hole 10c and the second tangent line L2 that intersects the line segment SB perpendicularly and contacts the outer periphery of the other through hole 10d. 2 There is a midpoint M in the width W of the protrusion 15 (the vertical width in FIG. 7) W. The width W of the second protrusion 15 is such that the second protrusion 15 has a width W in a direction perpendicular to the protrusion direction (left-right direction in FIG. 7) parallel to either the first contact line L1 or the second contact line L2. Length.

  That is, the midpoint M in the width W of the second protrusion 15 is defined by the first contact line L1 that contacts the outer periphery of one through hole 10c and the second contact line L2 that contacts the outer periphery of the other through hole 10d. It is formed within a band-like range (that is, connectable range SKH).

  The first contact line L1 and the second contact line L2 are arranged between the through holes 10c and 10d. Further, the midpoint M is within the connectable range SKH at any position in the protruding direction of the second protruding portion 15. These configurations are the same in the other embodiments.

  Furthermore, the width | variety of the 2nd protrusion part 15 is gradually large from the front end side of the protrusion direction by planar view. That is, both sides in the width direction on the root side are gently curved and spread so as to draw an arc so that the width on the root side of the second protrusion 15 is larger than the width on the tip side.

<Configuration on the first end plate 3 side>
As shown in FIG. 2, in the uppermost power generation unit 7 of the fuel cell stack 1, the upper surface of the upper interconnector 19 a is a plate material having a planar shape similar to the current collector plate 9 in plan view. A first end plate 3 is disposed. The first end plate 3 is made of the same material as the interconnector 19.

  The first end plate 3 has a function of taking out electric power to the outside in the same manner as the current collector plate 9 described above, and is thicker than the current collector plate 9. Since it is the same structure, it demonstrates easily.

  As shown in FIG. 8A, the first end plate 3 includes a current collector 81 having the same shape (square shape) as the planar shape of the stack body 20, and a first protrusion that protrudes outward from the outer periphery of the current collector 81. Part 13.

  In the current collecting portion 81, a rectangular frame-shaped edge portion 83 constituting the outer periphery is formed with eight through holes 10 through which the bolts 11 are inserted at equal intervals. In the current collector 81, a current collection area 85 (the hatched portion in FIG. 8A) similar to the current collection area 70 is formed.

  On the other hand, as shown in FIG. 8 (b), the first protrusion 13 has a pair of adjacent through holes 10 (for example, through holes 10g, 10h) in a portion corresponding to one side (left side) of the edge 83. Is formed so as to protrude outward from the outer periphery of the edge 83 on which is disposed. That is, the first protrusion 13 is formed so as to protrude outward from the left side of the outer periphery of the edge 83 between the through holes 10g and 10h perpendicularly to the left side.

A protrusion through hole 89 is formed on the tip end side of the first protrusion 13. In addition, a first output terminal 87 is connected to the first projecting portion 13 in order to extract electric power to the outside.
Furthermore, in the 1st protrusion part 13, it intersects perpendicularly | vertically with the line segment SB which connects the centroid of one through-hole (1st through-hole) 10g, and the centroid of the other through-hole (2nd through-hole) 10h. Between the first contact line L1 that contacts the outer periphery of one through hole 10g and the second contact line L2 that intersects the line segment SB perpendicularly and contacts the outer periphery of the other through hole 10h. There is a midpoint M in the width 13 (width in the vertical direction in FIG. 8B) W. The width W of the first protrusion 13 is the first protrusion in a direction perpendicular to the protrusion direction (left-right direction in FIG. 8B) parallel to either the first contact line L1 or the second contact line L2. This is the length of the portion 13.

  The first contact line L1 and the second contact line L2 are arranged between the through holes 10g and 10h. Further, the midpoint M is within the connectable range SKH at any position in the protruding direction of the first protruding portion 13.

Further, the first protruding portion 13 has a width on the base side gradually larger than the distal end side in the protruding direction in plan view.
d) Next, a method for manufacturing the fuel cell stack 1 will be briefly described.

[Manufacturing process of each member]
First, for example, each plate material made of SUS430 (that is, each plate material having a required thickness) is punched, and both end plates 3, 5, current collector plate 9, interconnector 19, fuel electrode frame 27, separator 25, fuel electrode current collector. 37 conductive plates 63 were produced.

The air electrode current collector 33 was formed on one surface of the interconnector 19 by cutting.
Further, the air electrode insulating frame 23 and the end insulating plate 64 were manufactured by punching the mica sheet.

  Furthermore, the spacer 61 was produced by punching the mica sheet, the conductive plate 63 was cut, and the conductive plate 63 was attached to the spacer 61 to produce the fuel electrode current collector 37.

[Manufacturing Process of Fuel Cell Single Cell 17]
The fuel cell single cell 17 was manufactured according to a conventional method.
Specifically, first, in order to form the fuel electrode 53, for example, a fuel electrode paste was prepared using a material composed of yttria-stabilized zirconia (YSZ) powder, nickel oxide powder, and a binder solution. Then, using this fuel electrode paste, a fuel electrode green sheet was produced by a known doctor blade method.

  Further, in order to produce the solid electrolyte layer 51, for example, a solid electrolyte paste was produced using a material composed of YSZ powder and a binder solution. And using this solid electrolyte paste, the solid electrolyte green sheet was produced by the doctor blade method.

Next, a solid electrolyte green sheet was laminated on the fuel electrode green sheet. And the laminated body was heated and sintered at predetermined temperature, and the sintered laminated body was formed.
Further, in order to form the air electrode 55, for _example, using a material consisting of _{La 1-x Sr x Co 1} -y Fe y O 3 powder and a binder solution, to prepare a cathode paste.

  Next, an air electrode paste was printed on the surface of the solid electrolyte layer 51 in the sintered laminate. Then, the printed air electrode paste was baked at a predetermined temperature so as not to become dense by baking, and the air electrode 55 was formed.

Thereby, the fuel cell single cell 17 was completed. The fuel cell single cell 17 was fixed to the separator 25 by brazing.
[Manufacturing process of fuel cell stack 1]
Next, the above-described members are combined in the order shown in FIG. 2 to form a laminate, and bolts 11 are fitted into the through holes 10 of the laminate, and nuts 12 are screwed into the bolts 11. The laminate was pressed and integrated to fix it.

Thus, the fuel cell stack 1 of Example 1 was completed.
e) Next, the effect of the first embodiment will be described.
In the first embodiment, in the current collector plate 9, a band-shaped range between a first contact line L1 that contacts the outer periphery of one through hole 10c and a second contact line L2 that contacts the outer periphery of the other through hole 10d. (That is, the midpoint M in the width W of the second protrusion 15 exists within the connectable range SKH).

  Similarly, in the first end plate 3, a band-shaped range between the first contact line L1 that contacts the outer periphery of one through hole 10g and the second contact line L2 that contacts the outer periphery of the other through hole 10h (that is, A midpoint M in the width W of the first protrusion 13 exists within the connectable range SKH).

  Accordingly, since the electric power (current) generated in the fuel cell stack 1 is not easily blocked by the through hole 10 (that is, the electric resistance is low), the second protrusion from the current collecting portion 65 of the current collecting plate 9. Electric power can be easily taken out of the fuel cell stack 1 through the portion 15, and electric power can be taken out of the fuel cell stack 1 from the current collecting portion 81 of the first end plate 3 through the first protrusion 13. Therefore, there is a remarkable effect that the voltage loss is small and the performance of the fuel cell stack 1 is improved.

  Moreover, since the first and second protrusions 13 and 15 having the midpoint M set as described above can be made compact, it is possible to suppress heat extraction from the stack body 20 in which the power generation units 7 are stacked. There are advantages.

  Further, in the first embodiment, the first and second protrusions 13 and 15 have a width that is gradually larger than the tip side in the protrusion direction in plan view. A current easily flows through the second projecting portion 15, and a current easily flows from the current collecting portion 81 to the first projecting portion 13. Furthermore, there is also an advantage that the strength of the base side of the first and second projecting portions 13 and 15 is large and is not easily damaged.

  In the first embodiment, the first projecting portion 13 of the first end plate 3 has the same configuration as the second projecting portion 15 of the current collector plate 9, but simply from the outer periphery of the first end plate 3. You may form so that the 1 protrusion part 13 may protrude. In other words, the first end plate 3 is configured such that the midpoint M in the width W of the first protrusion 13 is not provided in the band-shaped range between the first contact line L1 and the second contact line L2. Also good.

Next, the second embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
In the second embodiment, since the configuration of the current collector plate is different from that of the first embodiment, the differences will be mainly described. In addition, the same number is used for the same member number as in the first embodiment (the same applies hereinafter).

  Specifically, in the second embodiment, as illustrated in FIG. 9A, the current collector plate 91 includes a current collector 93 and a protrusion 95, of which the planar shape of the protrusion 95 is It is a trapezoid. That is, the protrusion 95 has a width that is gradually wider on the root side than on the tip side.

Also in the second embodiment, the same effects as in the first embodiment are obtained.
As a modified example, as shown in FIG. 9B, the planar shape of the protrusion 97 may be a rectangle having a certain width from the tip side to the root side.

  The projecting portions 95 and 97 correspond to the first projecting portion of the first embodiment (hereinafter, the “first projecting portion” and the “second projecting portion” are simply referred to as “projecting portions”. Sometimes). Moreover, you may employ | adopt the structure of these protrusion parts 95 and 97 for the protrusion part (1st protrusion part) of a 1st end plate (hereinafter the same).

Next, the third embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
In the third embodiment, since the planar shape of the through hole is different from that of the first embodiment, the differences will be mainly described.

Specifically, in the third embodiment, as shown in FIG. 10A, the planar shape of the through hole 101 is a square.
Even in the case of this rectangular through-hole 101, the band-like connectable range SKH can be set from the first contact line L1 and the second contact line L1 as in the first embodiment.

Also in the third embodiment, the same effects as in the first embodiment are obtained.
As a modified example, as shown in FIG. 10B, the planar shape of the through hole 111 may be another polygon (illustration is a hexagon).

  Although not shown, the connectable range SKH can be set in the same manner even if the through hole has a curved inner periphery.

Next, the fourth embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
In the fourth embodiment, the configuration on the first end plate side of the first embodiment is the same as that on the second end plate side.

  Specifically, in the fourth embodiment, as shown in FIG. 11, in the uppermost power generation unit 7 of the fuel cell stack 121, a current collector plate similar to that of the first embodiment is formed on the upper surface of the upper interconnector 19a. 123 are stacked.

  Further, an end insulating plate 125 similar to that of the first embodiment is laminated on the upper surface of the current collecting plate 123, and a first end plate 127 (however, the first end plate 127 similar to that of the first embodiment is provided on the upper surface of the end insulating plate 125). 1 protrusion is not formed).

Among these, the current collector plate 123 is the same as in the first embodiment, and the protrusion 131 protrudes from the outer periphery of the rectangular current collector 129 (in plan view).
Although not shown, the first output terminal 87 is connected to the protruding portion 131 in the same manner as the second output terminal 16.

  Also in the fourth embodiment, the same effects as in the first embodiment are obtained.

Next, although Example 5 is demonstrated, description of the content similar to the said Example 1 is abbreviate | omitted.
In the fifth embodiment, since the configuration of the end portion in the stacking direction of the fuel cell stack is different from that in the first embodiment, the differences will be mainly described.

  Specifically, in the fifth embodiment, as shown in FIG. 12A, the second end plate and the end insulating plate of the first embodiment are omitted on the lower end side of the fuel cell stack 141, and the current collector plate 143 is used as the second end plate.

In that case, it is preferable that the thickness of the current collector plate 143 is set to a thickness having sufficient strength as the second end plate (for example, equal to or greater than the thickness of the second end plate).
Here, the current collector plate 143 is directly tightened by the bolt 11 and the nut 12 through the insulator 8.

The fifth embodiment also has the advantages that the same effects as those of the first embodiment can be achieved and the configuration can be simplified.
Further, as a modification of the fifth embodiment, as shown in FIG. 12B, the first end plate of the first embodiment is omitted, and the current collector plate 147 having the first projecting portion 145 is replaced with the first end plate. It may be used as

  In that case, it is preferable that the thickness of the current collector plate 147 is set to a thickness having sufficient strength as the first end plate (for example, equal to or greater than the thickness of the first end plate).

Next, the sixth embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
In the sixth embodiment, since the configuration of the first end plate and the like is different from that of the first embodiment, different points will be mainly described.

  In the sixth embodiment, as shown in FIG. 13, the outer peripheral shape of the first end plate 151 is a square shape similar to the interconnector of the first embodiment in a plan view, and the first end plate 151 includes The 1st protrusion part like Example 1 is not provided.

  Specifically, the first output terminal 153 is fixed to the upper surface of the first end plate 151 by bolts 155. That is, the first output terminal 153 is an L-shaped plate material in which the tip end portion 153a and the extension portion 153b are bent vertically, and the tip end portion 153a is fixed to the first end plate 151 by the bolt 155. .

The first output terminal 155 is made of a material having a lower resistance than the interconnector 157 and the first end plate 155, for example, nickel or a nickel alloy.
As a result, the interconnector 157 and the first end plate 155 at the upper end and the first output terminal 153 are electrically connected.

  Further, the current collector plate 159 of the sixth embodiment has the same shape as that of the first embodiment, and the second output terminal 163 is fixed to the second protrusion 161 by a bolt 165 and a nut (not shown). Yes.

  The second output terminal 163 is an L-shaped plate material in which a distal end portion 163a and an extending portion 163b are bent vertically. The second output terminal 163 is made of a material having a lower resistance than the current collector plate 159, for example, nickel or a nickel alloy.

  Furthermore, in the first embodiment, as shown in FIG. 14, since the second projecting portion 161 is symmetrical in the vertical direction of FIG. 14, the axis of symmetry is a middle line ML indicated by a broken line in FIG. A midpoint M exists on the line ML.

Further, a range in which the second projecting portion 161 and the tip end portion 163a of the second output terminal 163 are overlapped is set as follows.
Specifically, a portion where the second projecting portion 161 and the second output terminal 163 are in contact with each other for electrical connection is set as a connection region SR (shaded portion in FIG. 14). The connection region SR is set to exist between the first contact line L1 and the second contact line L2. That is, the connection region SR is formed within the connectable range SKH.

  Also in the sixth embodiment, the same effects as in the first embodiment are obtained.

Next, although Example 7 is demonstrated, description of the content similar to the said Example 6 is abbreviate | omitted.
In the seventh embodiment, the configuration of the current collector plate (particularly the projecting portion) is different from that of the sixth embodiment, and therefore, different points will be mainly described.

  In the seventh embodiment, as shown in FIG. 15, the protruding portion (second protruding portion) 173 of the current collector plate 171 also functions as the second output terminal of the sixth embodiment, and the second output terminal is disposed. It is extended to the specified position.

  That is, the protrusion 173 of the seventh embodiment is bent in an L shape like the second output terminal and extends long in the stacking direction of the fuel cell stack 175. The second output terminal as in the first embodiment is not connected.

The seventh embodiment also has the advantages that the same effects as those of the sixth embodiment can be achieved and the configuration can be simplified.
Needless to say, the first projecting portion in the first embodiment may extend so as to function as an output terminal.

Next, although Example 8 will be described, description of the same contents as in Example 6 will be omitted.
In the eighth embodiment, since the configuration of the through-holes and the like is different from that of the sixth embodiment, different points will be mainly described.
In the eighth embodiment, as shown in FIG. 16, the through holes 10 formed in the edge portion 185 of the rectangular current collecting portion 183 of the current collecting plate 181 are arranged on each side of the square shape in plan view. There is no part, and a part is displaced in the outer peripheral direction.

That is, the through holes 10c and 10e located at the corners of the current collector 183 are arranged on the same side, but the through hole 10d therebetween is shifted to the right side in FIG.
Also in the eighth embodiment, as in the sixth embodiment, the midpoint in the width W of the second projecting portion 187 is within the band-shaped range between the first contact line L1 and the second contact line L2. M is arranged.

Therefore, the present Example 8 also has the same effect as the Example 6.
As mentioned above, although the Example etc. of this invention were described, this invention is not limited to the said Example etc., A various aspect can be taken.

  (1) For example, in the present invention, a plurality of flat cylindrical power generation units 193 each having a gas flow path 191 provided therein as shown in FIG. The present invention can also be applied to an arrayed fuel cell stack 195 or the like.

  Specifically, a fuel cell stack 195 in which a plurality of flat cylindrical power generation units 193 are arranged side by side in the thickness direction, and end plates 197 that also serve as current collector plates are arranged at both ends of the arrangement direction. In this case, the end plate 197 may be provided with a protruding portion 203 that protrudes to the outer peripheral side (at a position between the through holes 201) from the current collecting portion 199, as in the above embodiments.

  (2) Moreover, although it is preferable that the whole protrusion exists in the connectable range, a part may exist outside a connectable range. For example, when the width on the base side of the protruding portion is wide, a part of the base side may extend outside the connectable range.

  (3) In each of the above-described embodiments, the interconnector and the air electrode current collector are integrated, but the interconnector and the air electrode current collector are formed as separate members and are joined by a brazing material or the like. May be. For example, a block-like or long current collector may be joined to one surface of the flat interconnector.

(4) As the fuel electrode current collector, a known current collector such as a material such as a porous metal that does not buckle may be used in addition to the configuration of each of the above embodiments.
(5) In addition, you may combine the structure of each Example by applying to another Example suitably.

1, 121, 141, 155, 175, 195 ... Fuel cell stack 3, 5, 127, 145, 151, 197 ... End plate 7, 193 ... Power generation unit 9, 91, 123, 143, 147, 159, 171, 181 ... Current collecting plate 10, 10c, 10d, 10e, 10g, 10h, 101, 111, 171 ... Through hole 17 ... Fuel cell single cell 13, 15, 153, 163 ... Output terminal 19, 19a, 19b, 125, 157 ... Interconnector 33 ... Air electrode current collector 37 ... Fuel electrode current collector 51 ... Solid electrolyte layer 53 ... Fuel electrode 55 ... Air electrode 65, 81, 93, 129, 183, 199 ... Current collector 13, 15, 95, 97, 131, 145, 161, 173, 187, 203 ... Projection 70, 85 ... Current collection area

Claims (3)

A power generation unit comprising a fuel cell single cell having a fuel electrode, an air electrode, and a solid electrolyte;
A current collector plate for collecting the electric power generated by the single fuel cell via a current collector;
With
In the fuel cell stack in which a plurality of the power generation units are continuously arranged and the current collecting plate is arranged in a first direction in which the power generation units are continuous.
When viewed from the first direction,
The current collector plate includes a current collector disposed in a region where the power generation units overlap, and a projecting portion projecting from the current collector,
The current collector includes a current collection area in which the current collector is disposed, and a plurality of through holes that are disposed on the outer periphery of the current collection area, including adjacent first through holes and second through holes. And
A first tangent line perpendicularly intersecting a line segment connecting the centroid of the first through hole and the centroid of the second through hole and perpendicularly intersecting the line segment. And a midpoint in the width of the protruding portion exists between the second tangent line and the second tangent line that contacts the outer periphery of the second through hole,
The fuel cell stack, wherein the width is a length of the protruding portion in a direction perpendicular to a protruding direction parallel to either the first tangent line or the second tangential line.   2. The fuel cell stack according to claim 1, wherein, when viewed from the first direction, the protruding portion has a width on a root side larger than a tip side in the protruding direction.   3. The fuel cell stack according to claim 2, wherein when viewed from the first direction, the width of the protruding portion gradually increases toward the base side. 4.