JP4351617B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell in which a plurality of electrolyte / electrode assemblies configured by sandwiching an electrolyte between an anode electrode and a cathode electrode are disposed between a pair of separators each configured by a single plate.

  In general, a solid oxide fuel cell (SOFC) uses an oxide ion conductor, for example, stabilized zirconia, as an electrolyte, and an electrolyte / electrode assembly in which an anode electrode and a cathode electrode are disposed on both sides of the electrolyte ( A single cell) is sandwiched between separators (bipolar plates). This fuel cell is normally used as a fuel cell stack in which a predetermined number of single cells and separators are stacked.

In the fuel cell, when an oxidant gas, for example, a gas containing mainly oxygen or air (hereinafter also referred to as an oxygen-containing gas) is supplied to the cathode electrode, this oxidation is performed at the interface between the cathode electrode and the electrolyte. Oxygen in the agent gas is ionized, and oxide ions (O ²⁻ ) move to the anode electrode side through the electrolyte. Since the anode electrode is supplied with a fuel gas, for example, a gas mainly containing hydrogen (hereinafter also referred to as a hydrogen-containing gas) or CO, in this anode electrode, oxide ions and hydrogen (or CO) Reacts to produce water (or CO ₂ ). Electrons generated during that time are taken out to an external circuit and used as direct current electric energy.

  In this type of fuel cell, various proposals have been made for the purpose of reducing the thickness of the separator and reducing the number of components in order to reduce the dimension in the stacking direction. For example, as shown in FIG. 17, a fuel cell separator 1 disclosed in Patent Document 1 includes a thin sheet-like separator body 2 and a number of first fine bodies integrally formed on one side of the separator body 2. The projection 3 has a large number of second fine projections 4 integrally formed on the other surface of the separator body 2. A fuel gas passage 6 is formed between the separator 1 and the fuel electrode 5 via the first fine protrusion 3, while a second fine protrusion 4 is formed between the separator 1 and the air electrode 7. An oxidant gas passage 8 is formed through the.

  Further, in Patent Document 2, in a fuel cell composed of an anode electrode, a cathode electrode, an electrolyte plate, an anode gas channel, a cathode gas channel, and the like, the anode gas channel and the cathode gas channel are separated by a single plate. A fuel cell is disclosed.

  Furthermore, for example, a solid oxide fuel cell disclosed in Patent Document 3 is known. In Patent Document 3, as shown in FIG. 18, a plurality of rib-like members 3a and 3b are radially provided on both main surfaces 2a and 2b of the separator 1a. Grooves 4a and 4b reaching from the outer peripheral end to the center are formed at a predetermined depth on both main surfaces 2a and 2b of the separator 1a, and the fuel gas supply pipe 5a and the oxidation are formed in the grooves 4a and 4b. The agent gas supply pipe 6a is inserted. The fuel gas supply pipe 5a and the oxidant gas supply pipe 6a are flattened with their tips crushed, and are disposed in a state of being almost embedded in the separator 1a.

Japanese Patent Laying-Open No. 2002-75408 (FIG. 2) Japanese Patent Laid-Open No. 10-326624 (FIG. 1) Japanese Patent Laid-Open No. 11-16581 (FIG. 1)

  However, in the above-mentioned Patent Document 1, only the fuel gas passage 6 and the oxidant gas passage 8 are formed on both surfaces of one separator 1, and the supply form of the fuel gas and the oxidant gas is limited. End up. That is, the fuel gas and the oxidant gas are only supplied from one end portion of the fuel electrode 5 and the air electrode 7 toward the other end portion. For this reason, versatility is reduced, and depending on the shape of the fuel electrode 5 and the air electrode 7, the fuel gas and the oxidant gas may not be uniformly supplied to the entire surface of each electrode. Further, the above Patent Document 2 has the same problem as Patent Document 1.

  For this reason, in Patent Document 3, the flat fuel gas supply pipe 5a and the oxidant gas supply pipe 6a are embedded in the separator 1a. However, the fuel gas supply pipe 5a and the oxidant gas supply pipe are embedded in the separator 1a. There is a problem that the thickness in the stacking direction increases due to 6a.

  The present invention solves this type of problem, and provides a fuel cell capable of reliably applying a desired load to an electrolyte / electrode assembly while reducing the thickness in the stacking direction with a simple and compact configuration. The purpose is to provide.

In the fuel cell according to the present invention, a plurality of electrolyte / electrode assemblies constituted by sandwiching an electrolyte between an anode electrode and a cathode electrode are disposed between a pair of separators each constituted by one plate. . Each separator has a plurality of portions that sandwich one of the electrolyte / electrode assemblies together with another separator, that is, a plurality of sandwiching portions. Between the one side and the anode electrode of the sandwiching portions, together with the fuel gas passage for circulating fuel gas is formed by a plurality of first protrusions, and the other side surface and the cathode electrodes between the acid agent gas passage for circulating the oxidizing gas is formed by the second protrusion multiple.

The separator is provided with a passage member that forms a fuel gas supply passage that communicates with the fuel gas passage formed in each of the sandwiching portions from the fuel gas supply portion in the center portion. when a load is applied in the stacking direction of the separator and the electrode assembly, that having a elastically deformable configured bridges in the stacking direction.

  In addition, a plurality of first protrusions for forming a fuel gas passage between the separator electrode and the anode electrode are provided on one surface of the separator, and the cathode electrode is provided on the other surface of the separator. It is preferable that a plurality of second protrusions for forming the oxidant gas passage is provided.

  Here, one of the first or second projecting portions is an annular projecting portion projecting in an annular shape, and the remaining second or first projecting portion is associated with the projecting of the first or second projecting portion. It is preferable to dispose in the recessed portion that is depressed. Thereby, the tightening load can be efficiently transmitted to the electrolyte / electrode assembly. Moreover, since it is avoided that the volume of the gas passage becomes too small, it is avoided that the pressure loss rises excessively, and for this reason, the power generation reaction can be promoted.

  In this case, it is preferable to arrange the first protrusion and the second protrusion coaxially.

  Furthermore, it is preferable that the passage member has a curved cross-sectional shape and is set to be lower in rigidity than the first and second protrusions.

  Furthermore, the exhaust gas passage for discharging the reaction gas after being used for the reaction in the electrolyte / electrode assembly as exhaust gas in the stacking direction of the electrolyte / electrode assembly and the separator is provided, and the fuel gas supply unit includes the exhaust gas It is preferable that the air passage is provided in an airtight manner and extends in the stacking direction, and the passage member is disposed across the exhaust gas passage in a separator surface direction intersecting the stacking direction.

  In the present invention, a separator is provided that forms a fuel gas passage on one surface and an oxidant gas passage on the other surface, and the separator is provided with a passage member that forms a fuel gas supply passage. Therefore, the dimension (thickness) in the stacking direction of the separator is effectively shortened with a simple structure.

  Moreover, since the passage member is elastically deformable in the stacking direction when a load is applied in the stacking direction of the electrolyte / electrode assembly and the separator, the load in the stacking direction is surely applied to the electrolyte / electrode assembly. Can communicate. As a result, the adhesion between the electrolyte / electrode assembly and the current collector can be improved, and the current collection efficiency can be easily improved.

  FIG. 1 is a schematic perspective explanatory view of a fuel cell stack 12 in which a plurality of fuel cells 10 according to the first embodiment of the present invention are stacked in the direction of arrow A, and FIG. 14 is a partial cross-sectional explanatory view of the fuel cell system 16 accommodated in 14. FIG.

  The fuel cell 10 is a solid oxide fuel cell, and is used for various applications such as in-vehicle use in addition to installation. As shown in FIGS. 3 and 4, the fuel cell 10 is provided with a cathode electrode 22 and an anode electrode 24 on both surfaces of an electrolyte (electrolyte plate) 20 made of an oxide ion conductor such as stabilized zirconia, for example. The electrolyte / electrode assembly 26 is provided. The electrolyte / electrode assembly 26 is formed in a disk shape, and a barrier layer is provided at an outer peripheral end portion to prevent the oxidant gas from entering.

  The fuel cell 10 is configured by sandwiching a plurality of, for example, eight electrolyte / electrode assemblies 26 between a pair of separators 28. Between the separators 28, eight electrolyte / electrode assemblies 26 are arranged concentrically with the fuel gas supply communication hole (fuel gas supply part) 30 which is the central part of the separator 28.

  As shown in FIG. 3, the separator 28 is formed of, for example, a single metal plate or a carbon plate formed of a sheet metal such as a stainless alloy. The separator 28 has a first small-diameter end portion 32 that forms a fuel gas supply communication hole 30 at the center. A relatively large-diameter disk portion 36 is integrally provided via a plurality of first bridge portions 34 that are radially spaced apart from the first small-diameter end portion 32 at equal angular intervals. The disc portion 36 is set to have substantially the same dimensions as the electrolyte / electrode assembly 26.

  As shown in FIGS. 3, 5, and 6, adjacent disc portions 36 are separated from each other via slits 38 and projecting pieces 40 a and 40 b that protrude toward the disc portions 36 on both sides, respectively. Have A space portion 42 is formed between the projecting piece portions 40a and 40b adjacent to each other. In the space portion 42, an oxidant gas passage 50 (to be described later) and a direction other than the flow direction of the oxidant gas passage 50 (direction of arrow B) are formed. A baffle plate member 44 is provided to prevent the oxidant gas from entering in different directions. Each baffle plate member 44 is installed in the stacking direction so as to extend along the space portion 42. 3, 5, and 6, the baffle plate member 44 bent in the shape of a letter is shown, but any shape may be used as long as the oxidant gas can be prevented from entering.

  A first protrusion 48 that forms a fuel gas passage 46 for supplying fuel gas along the electrode surface of the anode electrode 24 is provided on the surface 36 a of each disk portion 36 that contacts the anode electrode 24 ( (See FIG. 5). A second protrusion 52 that forms an oxidant gas passage 50 for supplying an oxidant gas along the electrode surface of the cathode electrode 22 is provided on the surface 36 b of each disk portion 36 that contacts the cathode electrode 22. (See FIG. 6). As shown in FIG. 7, the first protrusion 48 and the second protrusion 52 protrude so as to extend in directions opposite to each other.

  In the present embodiment, the first protrusion 48 constitutes a ring-like protrusion, and the second protrusion 52 constitutes a mountain-like protrusion. The second protrusion 52, which is a mountain-shaped protrusion, is disposed so as to be surrounded by the first protrusion 48, which is a ring-shaped protrusion.

  Here, on the surface from which the second protrusion 52 protrudes, a recessed portion 53 that is depressed corresponding to the protrusion of the first protrusion 48 is formed. Therefore, the 2nd projection part 52 becomes a form arranged in this crevice 53.

  In the present embodiment, the center axis L1 of the first projecting portion 48, which is a perfect circular ring shape, and the projecting center axis L2 of the second projecting portion 52 are matched, in other words, the first The second protrusions 48 and 52 are arranged so that their centers coincide with each other and are coaxial with each other.

  As shown in FIGS. 8 and 9, a plurality of first and second protrusions 48 and 52 are formed, and the height H1 of the first protrusion 48 and the height H2 of the second protrusion 52 are shown. Is set to a relationship of H1 <H2. This is because the volume of the oxidant gas passage 50 is made larger than the volume of the fuel gas passage 46. The first and second protrusions 48 and 52 having such a shape can be provided by, for example, press molding, etching molding, or molding by cutting.

  In addition, while the 1st projection part 48 is comprised with a mountain-shaped protrusion, the 2nd projection part 52 may be comprised with a ring-shaped protrusion. In that case, it is preferable to set the height of the ring-shaped protrusion to be larger than the height of the mountain-shaped protrusion.

  As shown in FIGS. 3 to 6, the disk portion 36 is formed with a fuel gas inlet 54 for supplying fuel gas from the center side of the anode electrode 24 to the fuel gas passage 46. The position of the fuel gas inlet 54 is determined by the pressure of the fuel gas and the oxidant gas. For example, the center position of the disk part 36 or the flow direction of the oxidant gas with respect to the center of the disk part 36 ( It is set at a position eccentric to the upstream side (in the direction of arrow B).

  A passage member 56 is fixed to the surface of the separator 28 facing the cathode electrode 22 by, for example, brazing or laser welding. As shown in FIG. 3, the passage member 56 includes a second small diameter end portion 58 that forms the fuel gas supply communication hole 30 in the center portion. Eight second bridge portions 60 extend radially from the second small-diameter end portion 58, and each second bridge portion 60 extends from the first bridge portion 34 of the separator 28 to the fuel gas introduction port of the disc portion 36. It is fixed to 54.

  On the joint surface of the passage member 56, a plurality of slits 62 are formed radially at the second small diameter end portion 58 so as to communicate with the fuel gas supply communication hole 30. A concave portion 64 communicates with the slit 62 to prevent the brazing material from flowing around the second small-diameter end portion 58 and to make the flow of the fuel gas uniform. A fuel gas supply passage 66 communicating with the fuel gas passage 46 from the fuel gas supply communication hole 30 through the slit 62 and the recess 64 is formed between the first and second bridge portions 34 and 60.

  As shown in FIGS. 10 and 11, each passage member 56 is configured to have a curved cross section so that the second bridge portion 60 can be elastically deformed in the stacking direction with respect to a load in the stacking direction (arrow A direction). The Preferably, the second bridge portion 60 is configured in a cross-sectional arc shape or a cross-sectional slope shape, and the rigidity of the second bridge portion 60 is set lower than the rigidity of the first and second projecting portions 48 and 52. Has been.

  As shown in FIGS. 8 and 9, the oxidant gas passage 50 supplies the oxidant gas in the direction of arrow A from between the outer peripheral end of the electrolyte / electrode assembly 26 and the outer peripheral end of the disc portion 36. It communicates with the oxidant gas supply unit 68. The oxidant gas supply unit 68 is provided between the projecting piece portions 40 a and 40 b of each disk portion 36. Oxidant gas cannot enter from other than the oxidant gas supply unit 68 by the baffle plate member 44 installed in the space 42 in the projecting piece 40a, 40b.

  As shown in FIG. 8, an insulating seal 69 for sealing the fuel gas supply communication hole 30 is provided between the separators 28. The insulating seal 69 is made of, for example, mica material or ceramic material. The fuel cell 10 is formed with an exhaust gas passage 67 positioned inward of the disk portion 36 and extending in the stacking direction.

  As shown in FIGS. 1 and 2, the fuel cell stack 12 includes disk-shaped end plates 70 a and 70 b arranged at both ends in the stacking direction of the plurality of fuel cells 10, and the stacking direction via the tightening load applying mechanism 72. Tightened and held.

  The tightening load applying mechanism 72 has a first tightening portion 74a that applies a first tightening load T1 to the vicinity of the fuel gas supply communication hole 30, and the electrolyte / electrode assembly 26 more than the first tightening load T1. And a second tightening portion 74b that applies a small second tightening load T2 (T1> T2).

  The end plate 70 a is insulated from the housing 14, and a fuel gas supply port 76 is formed at the center, and the fuel gas supply port 76 communicates with the fuel gas supply communication hole 30 of each fuel cell 10. In the end plate 70a, two bolt insertion ports 78a are formed with the fuel gas supply port 76 interposed therebetween. The bolt insertion port 78 a corresponds to the exhaust gas passage 67 of the fuel cell stack 12.

  Eight circular openings 80 are formed in the end plate 70 a along a virtual circle centered on the fuel gas supply port 76, that is, corresponding to each electrolyte / electrode assembly 26. Each circular opening 80 communicates with a rectangular opening 82 projecting toward the fuel gas supply port 76, and a part of the rectangular opening 82 overlaps the exhaust gas passage 67. Exhaust gas is discharged.

  The end plate 70b is made of a conductive member. As shown in FIG. 2, a connection terminal portion 84 is bulged and formed at the center of the end plate 70b in the axial direction, and two bolt insertion openings 78b are formed with the connection terminal portion 84 interposed therebetween. Each bolt insertion port 78a, 78b is provided coaxially, and two fastening bolts (fastening tools) 86 are inserted therein, and the fastening bolts 86 are electrically insulated from the end plate 70b. A nut 88 is screwed onto the tip of the tightening bolt 86 to form a first tightening portion 74a, and a desired tightening load is applied between the end plates 70a and 70b.

  The connection terminal portion 84 is electrically connected to the output terminal 92 a through the conductive wire 90, and the output terminal 92 a is fixed to the housing 14.

  A second tightening portion 74b is disposed in each circular opening 80 of the end plate 70a. A pressing member 94 as a current collecting plate that is in electrical contact with the stacking direction end of the fuel cell stack 12 is disposed in the second tightening portion 74b. One end of the spring 96 abuts on the pressing member 94 and the other end of the spring 96 is supported by the inner wall portion of the housing 14. The spring 96 is set to a spring load lower than the first tightening load T1, and is made of, for example, ceramics in order to avoid the influence of heat during power generation and to provide insulation.

  A connecting conductor portion 98 is connected to the end portion of each pressing member 94, and the connecting conductor portion 98 and one end of one tightening bolt 86 are electrically connected via a conducting wire 100. The other end (head) of the tightening bolt 86 is close to the connection terminal portion 84, and the other end is electrically connected to the output terminal 92 b through the conductive wire 102. The output terminal 92b is electrically insulated in parallel with and close to the output terminal 92a and is fixed to the housing 14.

  In the housing 14, an air supply port 104 is formed adjacent to the output terminals 92a and 92b, and an exhaust port 106 is provided on the other end plate 70a side. A fuel gas supply port 108 is formed in the vicinity of the exhaust port 106 so that the exhaust gas and the fuel gas can exchange heat with each other. The fuel gas supply port 108 communicates with the fuel gas supply communication hole 30 through the reformer 110 as necessary. A heat exchanger 111 is disposed outside the reformer 110.

  The operation of the fuel cell stack 12 configured as described above will be described below.

  When assembling the fuel cell 10, first, as shown in FIG. 3, the passage member 56 is joined to the surface of the separator 28 facing the cathode electrode 22. For this reason, a fuel gas supply passage 66 communicating with the fuel gas supply communication hole 30 is formed between the separator 28 and the passage member 56, and the fuel gas supply passage 66 is connected to the fuel gas introduction port 54 from the fuel gas introduction port 54. It communicates with the passage 46 (see FIG. 8). The separator 28 is provided with a ring-shaped insulating seal 69 around the fuel gas supply communication hole 30.

  Thus, a separator 28 is formed, and eight electrolyte / electrode assemblies 26 are sandwiched between the separators 28 to obtain the fuel cell 10. As shown in FIGS. 3 and 4, each separator 28 has an electrolyte / electrode assembly 26 disposed between the surfaces 36 a and 36 b facing each other, and a fuel gas inlet 54 is disposed at the center of each anode electrode 24. Is done.

  A plurality of the fuel cells 10 are stacked in the direction of arrow A, and end plates 70a and 70b are disposed at both ends in the stacking direction. As shown in FIGS. 1 and 2, a tightening bolt 86 is inserted into each of the bolt insertion openings 78 a and 78 b of the end plates 70 a and 70 b, and a nut 88 is screwed onto the tip of the tightening bolt 86. Thus, the fuel cell stack 12 is configured, and the fuel cell stack 12 is mounted in the housing 14 in a state of being clamped and held in the stacking direction via the tightening load applying mechanism 72 (see FIG. 2).

  Therefore, a fuel gas (for example, hydrogen-containing gas) is supplied from a fuel gas supply port 108 provided in the housing 14, and an oxygen-containing gas (oxidant gas) is supplied from the air supply port 104 of the housing 14. (Hereinafter also referred to as air). The fuel gas is supplied to the fuel gas supply communication hole 30 of the fuel cell stack 12 through the reformer 110 and is moved in the stacking direction (arrow A direction), and the slit 62 in the separator 28 constituting each fuel cell 10. Is introduced into the fuel gas supply passage 66 (see FIG. 8).

  The fuel gas moves between the first and second bridge portions 34 and 60 along the fuel gas supply passage 66 and is introduced into the fuel gas passage 46 from the fuel gas inlet 54 formed in the disc portion 36. The fuel gas introduction port 54 is set at a substantially center position of the anode electrode 24 of each electrolyte / electrode assembly 26 or a position eccentric from the center position to the upstream side in the oxidant gas flow direction (arrow B direction). . Therefore, the fuel gas is supplied from the fuel gas inlet 54 to the center side of the anode electrode 24 and moves along the fuel gas passage 46 toward the outer periphery of the anode electrode 24 (see FIG. 9).

  On the other hand, the oxidant gas supplied to the oxidant gas supply unit 68 provided on the outer peripheral side of each fuel cell 10 is between the outer peripheral end of the electrolyte / electrode assembly 26 and the outer peripheral end of the disc part 36. It flows in the direction of arrow B from between and sent to the oxidant gas passage 50. As shown in FIGS. 8 and 9, in the oxidant gas passage 50, from the outer peripheral end portion (the outer peripheral end portion of the separator 28) side of the cathode electrode 22 of the electrolyte / electrode assembly 26 to the other outer peripheral end portion (the separator). The oxidant gas flows toward the central portion 28).

  Therefore, in the electrolyte / electrode assembly 26, the fuel gas is supplied from the center side of the electrode surface of the anode electrode 24 toward the outer peripheral side, and also toward one direction (arrow B direction) of the electrode surface of the cathode electrode 22. An oxidant gas is supplied (see FIGS. 9 and 11). At that time, oxide ions move to the anode electrode 24 through the electrolyte 20, and power is generated by a chemical reaction.

  Here, each fuel cell 10 is electrically connected in series in an arrow A direction (stacking direction), and as shown in FIG. 2, one pole is a connection provided on a conductive end plate 70b. The terminal portion 84 is connected to the output terminal 92a through the conducting wire 90. The other pole is connected to the output terminal 92b from the fastening bolt 86 via the conducting wire 102. For this reason, electrical energy can be taken out between the output terminals 92a and 92b.

  On the other hand, the exhaust gas mixed with the reacted fuel gas and oxidant gas moved to the outer periphery of each electrolyte / electrode assembly 26 moves in the stacking direction via the exhaust gas passage 67 formed in the separator 28, and the casing 14 exhaust ports 106 are exhausted to the outside.

  In this case, in the first embodiment, the separator 28 is composed of a single plate, and the both surfaces 36 a and 36 b of each disk portion 36 of the separator 28 are respectively in contact with the anode electrode 24 and the cathode electrode 22. First and second protrusions 48 and 52 are provided. A passage member 56 is fixed to the separator 28, and a fuel gas supply passage 66 communicating with the fuel gas passage 46 from the fuel gas supply communication hole 30 through the fuel gas introduction port 54 is formed by the passage member 56. .

  Therefore, the oxidant gas can be supplied in one direction (in the direction of arrow B) from the outer peripheral portion of the fuel cell 10 to the inside, while the fuel gas can flow from the central side of the anode electrode 24 toward the outer peripheral side. Therefore, the fuel gas can be supplied while being evenly distributed over the entire electrode surface of the anode electrode 24. Thereby, the power generation reaction of the electrolyte / electrode assembly 26 is performed uniformly over the entire power generation surface, and an effect is obtained that stable power generation is performed.

  Furthermore, in the first embodiment, as shown in FIGS. 10 and 11, each second bridge portion 60 provided in each passage member 56 is laminated with respect to the load in the lamination direction (arrow A direction). It is configured to have a curved cross section so as to be elastically deformable in the direction. That is, the rigidity of the second bridge part 60 is set lower than the rigidity of the first and second protrusions 48 and 52.

  Accordingly, when a tightening load is applied to the fuel cell 10 in the stacking direction, the second bridge portion 60 is easily elastically deformed by the first and second protrusions 48 and 52, so that the load in the stacking direction is the electrolyte / electrode. Transmission to the joined body 26 can be ensured. Therefore, the load is evenly distributed to the first and second protrusions 48 and 52, and the adhesion between the electrolyte / electrode assembly 26 and the first and second protrusions 48 and 52, which are the current collector, is improved. Therefore, it is possible to easily improve the current collection efficiency.

  And since the 2nd bridge part 60 is shape | molded by the cross-sectional curve shape, the contact area of this 2nd bridge part 60 and the cathode electrode 22 reduces. Thereby, the contact area between the cathode electrode 22 and the oxidant gas is increased, and the reaction efficiency is effectively improved.

  Furthermore, in the first embodiment, the first and second bridge portions 34 and 60 are provided in the exhaust gas passage 67, and the fuel gas supply passage formed between the first and second bridge portions 34 and 60. 66 is disposed across the exhaust gas passage 67 in the separator surface direction intersecting the stacking direction. Therefore, the fuel gas moving through the fuel gas supply passage 66 is effectively warmed by the exhaust heat from the exhaust gas passage 67, and the thermal efficiency is improved.

  12 is an exploded perspective view of a fuel cell 120 according to a second embodiment of the present invention, FIG. 13 is a cross-sectional view of a fuel cell stack 122 in which a plurality of the fuel cells 120 are stacked, and FIG. FIG. 3 is a schematic cross-sectional explanatory view for explaining the operation of the fuel cell 120. Note that the same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In each separator 28 constituting the fuel cell 120, a passage member 124 is fixed to the surface facing the anode electrode 24. The passage member 124 includes a second bridge portion 126 fixed to the first bridge portion 34 of the separator 28, and a fuel gas supply passage 66 is formed between the first and second bridge portions 34 and 126. The tip of each second bridge portion 126 terminates near the center position of the anode electrode 24 of the electrolyte / electrode assembly 26, and a plurality of fuel gas openings that open toward the anode electrode 24 are introduced into this tip portion. A mouth 128 is formed.

  Each passage member 124 is configured to have a curved cross section so that the second bridge 126 can be elastically deformed in the stacking direction with respect to a load in the stacking direction (arrow A direction). That is, the rigidity of the second bridge 126 is set lower than the rigidity of the first and second protrusions 48 and 52. The disk portion 36 of each separator 28 is not provided with the fuel gas inlet 54 of the first embodiment.

  In the second embodiment configured as described above, the fuel gas supplied to the fuel gas supply communication hole 30 moves along the fuel gas supply passage 66 formed between each separator 28 and the passage member 124. After that, the fuel gas is supplied from the plurality of fuel gas inlets 128 formed at the tip of the passage member 124 toward the anode electrode 24.

  In this case, when a tightening load is applied to the fuel cell 120 in the stacking direction, the second bridge 126 is easily elastically deformed by the first and second protrusions 48 and 52, so that the load in the stacking direction is applied to the electrolyte / electrode. Transmission to the joined body 26 can be ensured. Therefore, the load is evenly distributed to the first and second protrusions 48 and 52, and the adhesion between the electrolyte / electrode assembly 26 and the first and second protrusions 48 and 52, which are the current collector, is improved. Thus, the same effects as those of the first embodiment can be obtained, such as easily improving the current collection efficiency.

  In the above-described embodiment, as shown in FIG. 7, the first projecting portion 48 has a ring shape (a perfect circular shape). For example, as shown in FIG. May be. In this case, the intersection of the major axis “a” and the minor axis “b” of the ellipse is used as the center of the first protrusion 48, and the state where the axis passing through this center and the projecting central axis of the second protrusion 52 match each other is “first And the second protrusions 48 and 52 are coaxial ”.

  Moreover, as the second protrusion 52, a truncated cone shape having a perfectly circular cross section (top surface or the like) is illustrated in FIG. 7, but the “mountain protrusion” in the present invention is particularly limited to this. It is not intended to be included, but includes those whose cross section in the height direction has a trapezoidal shape. That is, for example, the horizontal cross section (top surface or the like) may be elliptical.

  Furthermore, in FIG. 7, the first and second protrusions 48 and 52 are coaxial, that is, the center axis L1 of the first protrusion 48 having a ring shape and the protrusion center axis L2 of the second protrusion 52. However, it is not necessary that the central axes L1 and L2 are matched with each other, in other words, the first and second protrusions 48 and 52 are not necessarily coaxial with each other. For example, as shown in FIG. 16, the protruding central axis L <b> 2 of the second protrusion 52 may be unevenly distributed from the central axis L <b> 1 of the first protrusion 48. Of course, in this case as well, the first protrusion 48 may be an elliptical ring shape, and the second protrusion 52 may be a mountain-shaped protrusion having an elliptical cross section in the horizontal direction.

1 is a schematic perspective view of a fuel cell stack in which a plurality of fuel cells according to a first embodiment of the present invention are stacked. 2 is a partial cross-sectional explanatory view of a fuel cell system in which the fuel cell stack is housed in a housing. FIG. FIG. 3 is an exploded perspective view of the fuel cell. It is a partially exploded perspective view showing the gas flow state of the fuel cell. It is explanatory drawing of one surface of the said separator. It is explanatory drawing of the other surface of the said separator. It is a perspective explanatory view of the 1st and 2nd projection parts formed in the separator. It is sectional drawing of the said fuel cell stack. It is a schematic cross-sectional explanatory drawing explaining operation | movement of the said fuel cell. It is a partially expanded perspective explanatory view of the passage member fixed to the separator. FIG. 9 is a cross-sectional view of the fuel cell stack taken along line XI-XI in FIG. 8. It is a disassembled perspective view of the fuel cell which concerns on the 2nd Embodiment of this invention. 2 is a cross-sectional view of a fuel cell stack in which a plurality of the fuel cells are stacked. FIG. It is a schematic cross-sectional explanatory drawing explaining operation | movement of the said fuel cell. FIG. 8 is an explanatory plan view of first and second protrusions of a different form from FIG. 7. FIG. 16 is a perspective explanatory view of first and second protrusions having a different form from that of FIGS. 7 and 15. 2 is a cross-sectional explanatory view of a fuel cell of Patent Document 1. FIG. FIG. 10 is a perspective explanatory view of a fuel cell of Patent Document 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 120 ... Fuel cell 12, 122 ... Fuel cell stack 20 ... Electrolyte 22 ... Cathode electrode 24 ... Anode electrode 26 ... Electrolyte electrode assembly 28 ... Separator 30 ... Fuel gas supply communication hole 34, 60, 126 ... Bridge part 36 ... disk portions 36a, 36b ... surface 42 ... space 44 ... baffle plate member 46 ... fuel gas passages 48, 52 ... projections 50 ... oxidant gas passage 53 ... recesses 54, 128 ... fuel gas inlets 56, 124 ... Passage member 66 ... Fuel gas supply passage 67 ... Exhaust gas passage 68 ... Oxidant gas supply portion 69 ... Insulating seal 70a, 70b ... End plate 72 ... Tightening load applying mechanism 74a, 74b ... Tightening portion

Claims (5)

A fuel cell configured by alternately laminating a plurality of electrolyte / electrode assemblies formed by sandwiching an electrolyte between an anode electrode and a cathode electrode and a separator formed by a single plate. ,
The separator has a plurality of sandwiching portions that sandwich one electrolyte / electrode assembly together with another separator,
Each of the sandwiching portions is formed on a surface facing the anode electrode, and faces the cathode electrode, and a plurality of first protrusions for constituting a fuel gas passage through which fuel gas flows through the anode electrode. A plurality of second protrusions for forming an oxidant gas passage formed on the side surface and allowing an oxidant gas to flow through the cathode electrode;
A fuel gas supply unit that supplies fuel gas along the stacking direction of the electrolyte / electrode assembly and the separator is provided at the center of the separator,
And a bridge portion provided on the separator and bridged from the fuel gas supply portion to a central portion of each of the clamping portions, and the bridge portion communicates from the fuel gas supply portion to each of the fuel gas passages. A passage member forming a fuel gas supply passage,
When the bridge member is set to be lower in rigidity than the first and second protrusions, the bridge member has a load applied in the stacking direction of the electrolyte / electrode assembly and the separator. A fuel cell configured to be elastically deformable in the stacking direction.   2. The fuel cell according to claim 1, wherein one of the first and second protrusions is an annular protrusion protruding in an annular shape, and the remaining second or first protrusion is the first or second protrusion. A fuel cell, characterized in that it is a mountain-shaped protrusion disposed on the opposite side of the annular protrusion in a recess formed by depression in the annular protrusion as the protrusion protrudes.   3. The fuel cell according to claim 2, wherein the first and second protrusions are coaxial with each other.   4. The fuel cell according to claim 1, wherein the bridge portion of the passage member has a curved cross-sectional shape. 5. 5. The fuel cell according to claim 1, wherein a reaction gas mixed with a fuel gas and an oxidant gas after being used for a reaction in the electrolyte / electrode assembly is used as an exhaust gas, to the electrolyte / electrode. An exhaust gas passage for discharging along the stacking direction of the joined body and the separator,
The exhaust gas passage is airtightly provided between the fuel gas supply unit and the clamping unit and extends in the stacking direction.
The fuel cell according to claim 1, wherein the bridge portion of the passage member is disposed along a separator surface direction that intersects the stacking direction in the exhaust gas passage.

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