JP2012129035A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress distortion of a separator due to heat as much as possible and to achieve improvement in power generation performance, thermal efficiency, and durability, with a simple configuration.SOLUTION: A separator 30 constituting a fuel cell 10 comprises: a holding part 32 which holds an electrolyte-electrode assembly 26 between itself and another separator 30 and is provided with a fuel gas passage 38 and an oxidant gas passage 28; a bridge part 34 in which a fuel gas supply passage 68, a fuel gas return passage 70, and an oxidant gas supply passage 74 are formed; and a reaction gas supply part 36 in which a fuel gas supply communication hole 48, a fuel gas lead-out communication hole 50, and an oxidant gas supply communication hole 52 are formed. The bridge part 34 goes around the entire circumference of the holding part 32 integrally with the reaction gas supply part 36.

Description

  The present invention relates to a fuel cell in which an electrolyte / electrode assembly configured by sandwiching an electrolyte between an anode electrode and a cathode electrode is laminated between separators.

  In general, a solid electrolyte 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 ( MEA) is sandwiched between separators (bipolar plates). This fuel cell is normally used as a fuel cell stack in which a predetermined number of electrolyte / electrode assemblies and separators are laminated.

  In the above fuel cell, in order to supply fuel gas (for example, hydrogen gas) and oxidant gas (for example, air) to the anode electrode and the cathode electrode constituting the electrolyte-electrode assembly, respectively, A fuel gas passage and an oxidant gas passage are formed along the same.

  For example, a flat plate type fuel cell disclosed in Patent Document 1 includes a separator 1 stacked on a power generation cell as shown in FIG. The separator 1 extends in the circumferential direction of the interconnect portion 2 where the power generation cells and the respective current collectors are stacked, and supports the opposing edges of the interconnect portion 2 at two locations. A pair of arm portions 3a and 3b is provided. Each of the arm portions 3a and 3b is formed in an elongated strip shape with a slight gap between the arm portions 3a and 3b, and thereby has flexibility so that it can be displaced in the stacking direction.

  The interconnect unit 2 has a function of supplying an oxidant gas and a fuel gas to the power generation cell, and an oxidant gas passage 4 through which an oxidant gas (air) flows, and a fuel gas passage through which the fuel gas flows. 5 are formed.

  An oxidant gas hole 6 and a fuel gas hole 7 penetrating in the plate thickness direction are provided at end portions of the arm portions 3a and 3b. The oxidant gas hole 6 communicates with the oxidant gas passage 4 through one arm portion 3a, and the fuel gas hole 7 communicates with the fuel gas passage 5 through the other arm portion 3b.

  Through the oxidant gas hole 6 and the fuel gas hole 7 through the oxidant gas passage 4 and the fuel gas passage 5, each electrode surface of each power generation cell from the gas discharge ports 4a and 5a provided at the center of the interconnect portion 2 An oxidant gas and a fuel gas are discharged to the central portion of the gas.

JP 2008-251236 A

  By the way, in said patent document 1, each arm part 3a, 3b is provided only in the angle range of about 90 degree | times along the outer periphery of the interconnect part 2 which is a clamping part. Therefore, there is a problem that a desired load cannot be independently applied to the interconnect portion 2 and the oxidant gas hole 6 and the fuel gas hole 7 which are the manifold portions.

  Moreover, the oxidant gas hole 6 and the fuel gas hole 7 are separated from each other at the diagonal position (diameter direction) of the interconnect portion 2. Accordingly, when the arm portions 3a and 3b are stretched due to heat, the positions of the oxidant gas holes 6 and the fuel gas holes 7 are fixed. There is a problem that distortion and the like are induced.

  The present invention solves this type of problem, and can suppress distortion of the separator caused by heat as much as possible with a simple configuration, and further improve power generation performance, thermal efficiency, and durability. An object of the present invention is to provide a fuel cell capable of satisfying the requirements.

  The present invention relates to a fuel cell in which an electrolyte / electrode assembly configured by sandwiching an electrolyte between an anode electrode and a cathode electrode is laminated between separators.

  In this fuel cell, the separator sandwiches the electrolyte / electrode assembly, supplies a fuel gas along the electrode surface of the anode electrode, and supplies an oxidant gas along the electrode surface of the cathode electrode. A sandwiching portion in which an oxidant gas passage is individually provided; a fuel gas supply passage connected to the sandwiching portion for supplying the fuel gas to the fuel gas passage; and returning the fuel gas flowing through the fuel gas passage A fuel gas return passage for forming an oxidant gas, and a bridge portion for forming an oxidant gas supply passage for supplying the oxidant gas to the oxidant gas passage; and a bridge portion connected to the bridge portion, A fuel gas supply passage for supplying to the supply passage, a fuel gas outlet passage for leading out the fuel gas flowing through the fuel gas return passage, and the oxidant gas The oxidant gas supply communication holes for supplying the oxidant gas supply passages each have a reaction gas supply part formed in the stacking direction, and the bridge part is integrated with the reaction gas supply part. It goes around the entire circumference.

  Further, in this fuel cell, it is preferable that at least one or more fuel gas supply holes for communicating the fuel gas passage and the fuel gas supply passage are provided in the clamping portion. Since the number of fuel gas supply holes can be set according to the area of the electrolyte / electrode assembly, it is possible to equalize the fuel gas concentration in the electrode surface of the electrolyte / electrode assembly to suppress fuel depletion. become.

  Furthermore, in this fuel cell, it is preferable that at least one or more oxidant gas supply holes for communicating the oxidant gas passage and the oxidant gas supply passage are provided in the sandwiching portion. Since the number of oxidant gas supply holes is set according to the area of the electrolyte / electrode assembly, the oxidant gas concentration in the electrode surface of the electrolyte / electrode assembly is equalized to suppress air depletion. Can do.

  Furthermore, in this fuel cell, it is preferable that the sandwiching portion is provided with at least one or more fuel gas return holes for communicating the fuel gas passage and the fuel gas return passage. The fuel gas can be smoothly and reliably returned from the fuel gas passage to the fuel gas return passage, and the fuel gas concentration in the electrode surface of the electrolyte / electrode assembly can be equalized.

  Further, in this fuel cell, at least one fuel gas return hole for connecting the fuel gas passage and the fuel gas return passage is provided in the sandwiching portion, and the fuel gas return hole is more than the fuel gas supply hole. It is preferable that it is arranged on the peripheral side of the clamping part. This is because the fuel gas supplied from the fuel gas supply hole to the anode electrode is smoothly introduced into the fuel gas return hole after flowing from the center side to the outer periphery side of the anode electrode.

  Further, in this fuel cell, a space portion is formed between the outer periphery of the sandwiching portion and the inner periphery of the bridge portion and the reaction gas supply portion, and the space portion receives the oxidant gas flowing through the oxidant gas passage. It is preferable to constitute an oxidant gas discharge communication hole for discharging.

  For this reason, the heat transfer area of the fuel gas supply passage and the oxidant gas supply passage, which are manifolds in the bridge portion, can be secured, and the high-temperature gas after reaction (oxidant gas after reaction) is forced to the bridge portion. The heat exchange is done by spraying on. Accordingly, the fuel gas and the oxidant gas flowing through the fuel gas supply passage and the oxidant gas supply passage are well heated by the high-temperature gas, and are self-sustaining (only the heat generated by themselves without applying heat from the outside). Maintaining the operating temperature) is promoted, and thermal efficiency is improved.

  Furthermore, in this fuel cell, the separator includes a first connection part that connects the sandwiching part and the bridge part, and a second connection part that connects the bridge part and the reactive gas supply part, and the first connection part. It is preferable that the portion and the second connecting portion are set at positions facing each other across the sandwiching portion. Thereby, a bridge part can be lengthened effectively and the load cutting (state which is not influenced by a mutual load) with a clamping part and a reactive gas supply part is performed reliably.

  In this fuel cell, it is preferable that a reforming catalyst for reforming the fuel gas is disposed in at least a part of the fuel gas supply passage. Therefore, the reforming reaction of the fuel gas is performed in the fuel gas supply passage, and the entire fuel cell stack in which the fuel cell and the plurality of fuel cells are stacked can be easily made compact. In addition, heat loss is reduced, and heat independence can be promoted.

  Furthermore, in this fuel cell, it is preferable that the reactive gas supply unit is provided with an oxidant gas supply communication hole between the fuel gas supply communication hole and the fuel gas outlet communication hole. Therefore, the configuration of the reactive gas supply unit is simplified and made compact.

  Furthermore, in this fuel cell, it is preferable that the fuel gas supply communication hole, the oxidant gas supply communication hole, and the fuel gas outlet communication hole are arranged along the outer shape of the clamping portion. As a result, the entire fuel cell can be easily reduced in size.

  In this fuel cell, it is preferable that the reaction gas supply unit is provided with a fuel gas outlet communication hole between the fuel gas supply communication hole and the oxidant gas supply communication hole. For this reason, the fuel gas and the oxidant gas that are the supply gases are heated by the high-temperature fuel gas that flows through the fuel gas passage and moves through the fuel gas lead-out communication hole. Therefore, thermal independence is promoted and thermal efficiency is improved.

  Furthermore, in this fuel cell, it is preferable that the fuel gas supply communication hole, the fuel gas outlet communication hole, and the oxidant gas supply communication hole are arranged along a direction intersecting the outer shape of the sandwiching portion. Thereby, the structure of the reactive gas supply unit is simplified and made compact.

  Furthermore, in this fuel cell, it is preferable that the sandwiching portion has a circular shape or an oval shape, and the bridge portion has a circular ring shape or an oval ring shape integrally with the reaction gas supply portion. For this reason, the bridge portion can be easily lengthened and the load can be cut off, and the influence of heat (for example, concentration of thermal stress) can be suppressed.

  In addition, this fuel cell is preferably a solid oxide fuel cell. By applying it to a high-temperature fuel cell, it becomes possible to satisfactorily suppress the sandwiched portion and the thermal strain of the electrolyte / electrode assembly due to thermal stresses of particular concern.

  Further, the fuel cell is preferably a flat plate stacked solid oxide fuel cell. For this reason, it can be suitably applied to a high temperature fuel cell such as a flat plate SOFC (solid oxide fuel cell).

  According to the present invention, the fuel gas supply communication holes, the fuel gas outlet communication holes, and the oxidant gas supply communication holes, which are the manifolds, are provided in a concentrated manner in a single reaction gas supply unit. Accordingly, the manifolds that require a high load for gas sealing are not dispersed from each other, and the occurrence of distortion in the separator due to expansion and contraction caused by heat can be suppressed as much as possible.

  In addition, poor adhesion between the separator and the electrolyte / electrode assembly due to strain is suppressed, and power generation performance is improved. Furthermore, since the damage of the electrolyte / electrode assembly due to strain is suppressed, the durability of the electrolyte / electrode assembly is improved satisfactorily.

  Further, the reaction gas supply section, which is a reaction gas manifold, is provided with a fuel gas supply communication hole, a fuel gas outlet communication hole, and an oxidant gas supply communication hole, and the bridge section has a fuel gas supply passage, a fuel gas return passage. A passage and an oxidant gas supply passage are formed. Thereby, the fuel gas and oxidant gas which are supply gas are easy to be heated with high temperature fuel gas, thermal self-sustainment is promoted, and thermal efficiency is improved.

  Furthermore, the bridge part goes around the entire outer periphery of the clamping part integrally with the reaction gas supply part. Thereby, the fuel gas and oxidant gas which are supply gas are heated by the high temperature exhaust gas (oxidant gas) after reaction discharged | emitted by the outer periphery of a clamping part. For this reason, thermal independence is promoted and thermal efficiency is improved.

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. It is a partially exploded perspective view of the fuel cell stack. 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 a schematic cross-sectional explanatory drawing of the said fuel cell. It is a plane explanatory view of the 1st plate which constitutes the separator of the fuel cell. It is one plane explanatory drawing of the 2nd plate which comprises the said separator. It is the other plane explanatory view of the 2nd plate. It is a plane explanatory view of the 3rd plate which constitutes the separator. It is a plane explanatory view of the separator which constitutes the fuel cell concerning a 2nd embodiment of the present invention. It is a disassembled perspective view of the fuel cell which concerns on the 3rd Embodiment of this invention. It is one plane explanatory drawing of the separator which comprises the said fuel cell. It is the other plane explanatory view of the separator. It is a plane explanatory view showing another composition of the separator. It is a side view of the fuel cell stack which concerns on the 4th Embodiment of this invention. 2 is an explanatory diagram of a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, the fuel cell 10 according to the first embodiment of the present invention is a solid oxide fuel cell, and a plurality of layers are stacked in the direction of arrow A to constitute a fuel cell stack 12. As will be described later, the fuel cell 10 is a flat plate stacked solid oxide fuel cell. The fuel cell stack 12 is used for various purposes such as in-vehicle use as well as stationary use.

  As shown in FIGS. 3 to 5, 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 (MEA) 26 is provided. The electrolyte / electrode assembly 26 is formed in an oval shape (or an oval shape), and the outer dimensions of the cathode electrode 22 are set to be smaller than the outer dimensions of the electrolyte 20 and the anode electrode 24.

  The electrolyte / electrode assembly 26 is provided with an oval (or elliptical) cathode current collector 22 a in contact with the cathode electrode 22. The cathode current collector 22a is made of, for example, foam metal, and an oxidant gas passage 28 is formed by the internal space.

  The fuel cell 10 is configured by sandwiching a single electrolyte / electrode assembly 26 between a pair of separators 30. In practice, the separators 30 and the electrolyte / electrode assemblies 26 are alternately stacked.

  The separator 30 includes a sandwiching portion 32 that sandwiches the electrolyte / electrode assembly 26, a narrow bridge portion 34 that is coupled to the sandwiching portion 32 via a first connection portion 33, and a second connection to the bridge portion 34. And a reaction gas supply unit 36 that is integrally connected via the unit 35. The 1st connection part 33 and the 2nd connection part 35 are set in the position which mutually opposes on both sides of the clamping part 32. FIG.

  The bridge portion 34 circulates around the entire outer periphery of the sandwiching portion 32 integrally with the reaction gas supply portion 36. The bridge part 34 and the reactive gas supply part 36 are formed in an oval shape (or an elliptical shape) as in the sandwiching part 32 as a whole.

  An oxidant gas passage 28 is formed between the sandwiching portion 32 and the cathode electrode 22 of the electrolyte / electrode assembly 26 with a cathode current collector 22a interposed therebetween, and the anode of the electrolyte / electrode assembly 26 is formed. A fuel gas passage 38 is formed between the electrode 24 and the separator 30. The bridge portion 34 is provided with a positioning portion 39 that protrudes in a direction orthogonal to the reaction gas supply portion 36.

  The separator 30 includes, for example, a first plate 40, a second plate 42, and a third plate 44 that are three plates, and the first plate 40, the second plate 42, and the third plate 44 are, for example, It is made of a sheet metal such as a stainless alloy, and is joined to each other by brazing, diffusion bonding, laser welding, or the like. The separator 30 may be configured by joining four or more plates.

  As shown in FIGS. 3 and 6, the first plate 40 includes a rectangular or oval first reaction gas supply member 46 that constitutes the reaction gas supply unit 36. The first reaction gas supply member 46 is used to lead out the fuel gas flowing through the fuel gas supply communication hole 48 and the fuel gas passage 38 for supplying the fuel gas along the stacking direction (arrow A direction). A fuel gas outlet communication hole 50 and an oxidant gas supply communication hole 52 for supplying an oxidant gas are formed.

  The reactive gas supply unit 36 is provided with an oxidant gas supply communication hole 52 between the fuel gas supply communication hole 48 and the fuel gas outlet communication hole 50, and the fuel gas supply communication hole 48 and the oxidant gas supply. The communication hole 52 and the fuel gas outlet communication hole 50 are arranged along the outer shape of the clamping part 32.

  The first reactive gas supply member 46 is connected to a narrow first bridge member 54 constituting the bridge portion 34 via the second connection portion 35a, and the first bridge member 54 has a first connection. A relatively large-diameter first clamping member 56 is integrally provided via the portion 33a.

  The first clamping member 56 constitutes the clamping part 32 and is set in a disk shape having a larger diameter than the diameter of the electrolyte / electrode assembly 26. A plurality of protrusions 57 are formed in the first clamping member 56 to form the fuel gas passage 38, and a fuel gas supply hole 58 for supplying fuel gas is provided, for example, in the first clamping member 56. At least two are formed corresponding to each center of the ellipse. A plurality of fuel gas return holes 60 for returning the fuel gas flowing through the fuel gas passage 38 are formed on the outer peripheral edge of the first clamping member 56 so as to go around the outer periphery of the outer shape of the electrolyte / electrode assembly 26. It is formed on a virtual line having a shape (or an elliptical shape).

  As shown in FIG. 7, the second plate 42 includes a rectangular or oval second reaction gas supply member 62 that constitutes the reaction gas supply unit 36. The second reaction gas supply member 62 is provided with a fuel gas supply communication hole 48, an oxidant gas supply communication hole 52, and a fuel gas outlet communication hole 50. A narrow second bridge member 64 is connected to the second reactive gas supply member 62 via a second connecting portion 35b, and a comparison is made to the second bridge member 64 via a first connecting portion 33b. A second holding member 66 having a large diameter is integrally provided.

  On the surface side of the second bridge member 64 (on the side of the joint surface with the first plate 40), a fuel gas supply passage 68 and a fuel gas return passage are provided in each arcuate portion partitioned by the first and second connecting portions 33b and 35b. 70 is provided. Specifically, a fuel gas supply passage 68 is formed on one side 34 a side of the bridge portion 34, and a fuel gas return passage 70 is formed on the other side portion 34 b side of the bridge portion 34.

  The fuel gas supply passage 68 has one end communicating with the fuel gas supply communication hole 48, and the other end extending through the first connecting portion 33 b into the second holding member 66, and the center of the second holding member 66 An oval fuel gas chamber 68a is formed at the portion. In the fuel gas chamber 68a, a reforming catalyst (for example, nickel foam and catalyst) 72 for reforming the fuel gas as necessary is disposed.

  The fuel gas return passage 70 has one end communicating with the fuel gas outlet communication hole 50 and the other end extending into the second clamping member 66 through the first connecting portion 33b. The other end corresponds to the position of the fuel gas return hole 60 of the first holding member 56 and is formed in an oval shape (or an oval shape) along the outer peripheral edge of the second holding member 66.

  As shown in FIG. 8, an oxidant gas supply passage 74 that communicates with the oxidant gas supply communication hole 52 is provided on the back surface side of the second bridge member 64 (on the joint surface side with the third plate 44). The oxidant gas supply passage 74 extends into the second holding member 66 through the first connecting portion 33b, and an oval terminal portion 74a is formed at the center of the second holding member 66.

  As shown in FIG. 9, the third plate 44 includes a rectangular or oval third reaction gas supply member 76 that constitutes the reaction gas supply unit 36. The third reaction gas supply member 76 is provided with a fuel gas supply communication hole 48, an oxidant gas supply communication hole 52, and a fuel gas outlet communication hole 50. A narrow second bridge member 78 is connected to the third reactive gas supply member 76 via a second connecting portion 35c, and a comparison is made to the second bridge member 78 via a first connecting portion 33c. A third pinching member 80 having a large diameter is integrally provided.

  In the third clamping member 80, at least two oxidant gas supply holes 82 for supplying an oxidant gas are formed corresponding to the centers of the ellipses of the third clamping member 80, for example. The oxidant gas supply hole 82 is provided at a position corresponding to the end portion 74 a of the second clamping member 66.

  As shown in FIGS. 3 and 5, the sandwiching portion 32 has a sealing member 86 that seals a space 84 formed between the sandwiching portion 32 and the anode electrode 24 side of the electrolyte / electrode assembly 26. Provided. The sealing member 86 has a substantially ring shape, and includes a flange portion 86 a that is fixed around the plurality of fuel gas return holes 60 in the first clamping member 56, and the outer side of the electrolyte 20 of each electrolyte / electrode assembly 26. The peripheral portion is integrally provided with a pressing portion 86b that rotates around the outside of the cathode electrode 22 and presses the peripheral portion.

  In the sealing member 86, first, after the pressing portion 86 b is joined to the outer peripheral edge portion of the electrolyte 20 via a glass seal (not shown), the flange portion 86 a is laser welded to the first clamping member 56. .

  As shown in FIG. 3, in the fuel cell 10, a substantially ring-shaped space portion is formed between the outer periphery of the sandwiching portion 32 and the inner periphery of the bridge portion 34 and the reactive gas supply portion 36. This space portion constitutes an oxidant gas discharge communication hole 88 for discharging the oxidant gas flowing through the oxidant gas passage 28.

  As shown in FIGS. 1 and 2, the fuel cell stack 12 has an end plate 90 disposed at one end (lower end) in the stacking direction of the plurality of fuel cells 10. The end plate 90 has a shape similar to the outer shape of the fuel cell 10 and a large size. The end plate 90 includes a fuel gas supply pipe 92, a fuel gas outlet pipe 94, and an oxidant gas supply pipe 96 that communicate with the fuel gas supply communication hole 48, the fuel gas outlet communication hole 50, and the oxidant gas supply communication hole 52, respectively. Provided.

  The end plate 90 is provided with a first load applying mechanism 98 that applies a tightening load to the sandwiching portion 32 in the stacking direction. The first load applying mechanism 98 includes a pressing member 100 disposed on the reaction gas supply unit 36 that constitutes the fuel cell 10 disposed at the top. On the end plate 90, a plurality of bolts 104 are inserted into the pressing member 100 and screwed into the end plate 90, whereby a desired tightening load is applied to the sandwiching portion 32. Between each clamping part 32, the sealing member (ceramic) 102 is interposed, for example. Positioning pins 106 are erected on the end plate 90, and the positioning pins 106 engage with the positioning portions 39 of the separators 30.

  For example, a weight member 108 is placed as a second load applying mechanism on the sandwiching portion 32 constituting the fuel cell 10 disposed at the uppermost position. A larger tightening load is applied to the reaction gas supply unit 36 stacked in the direction of arrow A than the clamping unit 32 in the stacking direction.

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

  As shown in FIGS. 1 and 2, fuel gas (for example, hydrogen-containing gas) is supplied from a fuel gas supply pipe 92 provided in the end plate 90 to the fuel gas supply communication hole 48, and an oxidant gas supply pipe. An oxygen-containing gas (hereinafter also referred to as air) that is an oxidant gas is supplied from 96 to the oxidant gas supply communication hole 52.

  As shown in FIGS. 4 and 5, the fuel gas is supplied to each fuel cell 10 while moving in the stacking direction (arrow A direction) along the fuel gas supply communication hole 48 of the fuel cell stack 12. It moves along the passage 68 in the surface direction of the separator 30.

  The fuel gas is introduced into a fuel gas chamber 68a formed in the holding portion 32, and is reformed by a reforming catalyst 72 provided in the fuel gas chamber 68a. The reformed fuel gas is introduced into the fuel gas passage 38 through a pair of fuel gas supply holes 58 formed in the first clamping member 56 as a hydrogen rich gas.

  The pair of fuel gas supply holes 58 is set at a substantially central position of the anode electrode 24 of the electrolyte / electrode assembly 26. Therefore, the fuel gas is supplied from the pair of fuel gas supply holes 58 to substantially the center of the anode electrode 24, and then moves along the fuel gas passage 38 toward the outer periphery of the anode electrode 24.

  The fuel gas flowing through the fuel gas passage 38 moves to a plurality of fuel gas return holes 60 formed outside the outer periphery of the electrolyte / electrode assembly 26. Accordingly, the fuel gas is supplied to the fuel gas return passage 70 through the fuel gas return hole 60, and is led out to the fuel gas outlet communication hole 50 through the fuel gas return passage 70.

  On the other hand, while the air moves in the stacking direction (arrow A direction) along the oxidant gas supply passage 52 of the fuel cell stack 12, the separator 30 extends along the oxidant gas supply passage 74 provided in each fuel cell 10. Move in the direction of the surface.

  The air flows through the terminal portion 74 a of the oxidant gas supply passage 74, and then is introduced into the oxidant gas passage 28 through a pair of oxidant gas supply holes 82 formed in the third clamping member 80. The pair of oxidant gas supply holes 82 is set at a substantially central position of the cathode electrode 22 of the electrolyte / electrode assembly 26. For this reason, air is supplied from the oxidant gas supply hole 82 to substantially the center of the cathode electrode 22 and then moves along the oxidant gas passage 28 toward the outer periphery of the cathode electrode 22.

  Accordingly, 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 peripheral end side, and from the center side of the electrode surface of the cathode electrode 22 to the peripheral end side. Air is supplied in the direction. At that time, oxide ions move to the anode electrode 24 through the electrolyte 20, and power is generated by a chemical reaction.

  In this case, in the first embodiment, the fuel gas supply communication hole 48, the fuel gas outlet communication hole 50, and the oxidant gas supply communication hole 52, which are each manifold, are provided concentrated on the single reaction gas supply unit 36. It has been. Therefore, the manifolds (fuel gas supply communication holes 48, fuel gas outlet communication holes 50, and oxidant gas supply communication holes 52) that require a high load for gas sealing are not dispersed from each other. Thereby, the effect that it can suppress as much as possible that distortion generate | occur | produces in the separator 30 by the expansion | swelling and shrinkage | contraction resulting from a heat | fever is acquired.

  In addition, poor adhesion between the separator 30 and the electrolyte / electrode assembly 26 due to strain is suppressed, and power generation performance is improved. Furthermore, since damage to the electrolyte / electrode assembly 26 due to strain is suppressed, the durability of the electrolyte / electrode assembly 26 is improved satisfactorily.

  Furthermore, the reaction gas supply section 36 that is a reaction gas manifold is provided with a fuel gas supply communication hole 48, a fuel gas outlet communication hole 50, and an oxidant gas supply communication hole 52, and the bridge section 34 includes a fuel gas supply communication hole 48. A supply passage 68, a fuel gas return passage 70, and an oxidant gas supply passage 74 are formed. As a result, the fuel gas and the oxidant gas as the supply gas are easily heated by the high-temperature fuel gas, and the heat is self-supporting (maintaining the operating temperature of the fuel cell only by the heat generated by itself without applying heat from the outside). Is promoted to improve thermal efficiency.

  In the first embodiment, the bridge portion 34 circulates around the entire outer periphery of the sandwiching portion 32 integrally with the reaction gas supply portion 36. As a result, the fuel gas and the oxidant gas that are the supply gas are heated by the high-temperature exhaust gas (oxidant gas) after the reaction that is discharged to the outer periphery of the sandwiching portion 32. For this reason, the effect that heat self-sustainment is promoted and thermal efficiency is improved is obtained.

  Further, the clamping portion 32 is provided with a plurality of, for example, two fuel gas supply holes 58 that allow the fuel gas passage 38 and the fuel gas supply passage 68 to communicate with each other. Since the number of fuel gas supply holes 58 can be set according to the area of the electrolyte / electrode assembly 26, the fuel gas concentration in the electrode surface of the electrolyte / electrode assembly 26 is equalized to suppress fuel depletion. It becomes possible.

  Furthermore, the sandwiching portion 32 is provided with a plurality of, for example, two oxidant gas supply holes 82 for communicating the oxidant gas passage 28 and the oxidant gas supply passage 74. Since the number of the oxidant gas supply holes 82 is set according to the area of the electrolyte / electrode assembly 26, the concentration of the oxidant gas in the electrode surface of the electrolyte / electrode assembly 26 is equalized and air exhaustion is eliminated. Can be suppressed.

  The sandwiching portion 32 is provided with a plurality of fuel gas return holes 60 that allow the fuel gas passage 38 and the fuel gas return passage 70 to communicate with each other. The fuel gas can be smoothly and surely returned from the fuel gas passage 38 to the fuel gas return passage 70, and the fuel gas concentration in the electrode surface of the electrolyte / electrode assembly 26 can be equalized.

  Further, the sandwiching portion 32 is provided with a plurality of fuel gas return holes 60 that allow the fuel gas passage 38 and the fuel gas return passage 70 to communicate with each other, and the fuel gas return hole 60 is more than the fuel gas supply hole 58. It is arranged on the peripheral side of the clamping part 32. This is because the fuel gas supplied from the fuel gas supply hole 58 to the anode electrode 24 circulates from the substantially central side to the outer peripheral side of the anode electrode 24 and then smoothly introduced into the fuel gas return hole 60.

  Furthermore, in the fuel cell 10, a substantially ring-shaped space portion is formed between the outer periphery of the sandwiching portion 32 and the inner periphery of the bridge portion 34 and the reactive gas supply portion 36. This space portion constitutes an oxidant gas discharge communication hole 88 for discharging the oxidant gas flowing through the oxidant gas passage 28.

  For this reason, the heat transfer area of the fuel gas supply passage 68 and the oxidant gas supply passage 74 which are manifolds in the bridge portion 34 can be secured, and the high-temperature gas after the reaction (oxidant gas after the reaction) is supplied to the bridge. The heat is exchanged by forcibly spraying the part 34. Therefore, the fuel gas and the oxidant gas flowing through the fuel gas supply passage 68 and the oxidant gas supply passage 74 are favorably heated by the high-temperature gas, heat self-sustainment is promoted, and thermal efficiency is improved.

  The separator 30 includes a first connecting portion 33 that connects the sandwiching portion 32 and the bridge portion 34, and a second connecting portion 35 that connects the bridge portion 34 and the reactive gas supply portion 36. And the 1st connection part 33 and the 2nd connection part 35 are set in the position which mutually opposes on both sides of the clamping part 32. As shown in FIG. Thereby, the bridge part 34 can be lengthened effectively, and the load cutting (state which is not influenced by a mutual load) with the clamping part 32 and the reactive gas supply part 36 is performed reliably.

  Further, as shown in FIG. 7, an end portion of the fuel gas supply passage 68 forms an oval fuel gas chamber 68a at the center of the second clamping member 66, and the fuel gas chamber 68a includes a fuel gas chamber 68a. A reforming catalyst 72 for reforming the gas is provided. Therefore, the reforming reaction of the fuel gas is performed in the fuel gas chamber 68a, and the entire fuel cell stack 12 in which the fuel cell 10 and the plurality of fuel cells 10 are stacked can be easily made compact. In addition, the heat loss is reduced and the heat self-sustainment can be promoted.

  Furthermore, the reactive gas supply unit 36 is provided with an oxidant gas supply communication hole 52 between the fuel gas supply communication hole 48 and the fuel gas outlet communication hole 50. Therefore, the configuration of the reaction gas supply unit 36 is simplified and made compact. At that time, the fuel gas supply communication hole 48, the oxidant gas supply communication hole 52, and the fuel gas outlet communication hole 50 are arranged along the outer shape of the sandwiching portion 32. Thereby, size reduction of the fuel cell 10 whole can be achieved easily.

  The sandwiching portion 32 has a circular shape or an oval shape, and the bridge portion 34 has a circular ring shape or an oval ring shape integrally with the reaction gas supply portion 36. For this reason, the bridge part 34 can be easily lengthened to cut the load, and the influence of heat (for example, concentration of thermal stress) can be suppressed.

  Furthermore, the fuel cell 10 is a flat plate stacked solid oxide fuel cell. Therefore, it can be suitably applied to a high temperature fuel cell such as a flat plate SOFC (solid oxide fuel cell).

  FIG. 10 is an explanatory plan view of the separator 110 constituting the fuel cell according to the second embodiment of the present invention. 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. Similarly, in the third and subsequent embodiments described below, detailed description thereof is omitted.

  The separator 110 includes a clamping unit 112, a bridge unit 114, and a reaction gas supply unit 36. The sandwiching portion 112 has a circular shape, while the electrolyte / electrode assembly (not shown) is similarly formed in a circular shape.

  The bridge portion 114 circulates around the entire outer periphery of the sandwiching portion 112 integrally with the reaction gas supply portion 36. The bridge portion 114 and the reaction gas supply portion 36 are formed in a circular shape as in the sandwiching portion 112 as a whole. The fuel gas supply hole 58 and the oxidant gas supply hole 82 are provided one by one corresponding to the center of the sandwiching portion 112.

  In the second embodiment configured as described above, the same effect as in the first embodiment can be obtained. In the third and subsequent embodiments described below, an ellipse (or an ellipse) is formed as in the first embodiment, but a circle is formed as in the second embodiment. May be.

  FIG. 11 is an exploded perspective view of a fuel cell 120 according to the third embodiment of the present invention.

  The fuel cell 120 is configured by sandwiching one electrolyte / electrode assembly 26 between a pair of separators 122. As shown in FIGS. 11 to 13, the separator 122 includes a sandwiching portion 32 that sandwiches one electrolyte / electrode assembly 26, a narrow bridge portion 34 having one end connected to the sandwiching portion 32, And a reactive gas supply unit 124 to which the other end of the bridge unit 34 is integrally connected.

  In the reaction gas supply unit 124, a fuel gas supply communication hole 48, a fuel gas outlet communication hole 50, and an oxidant gas supply communication hole 52 are sequentially formed toward the outside of the separator 122. The reactive gas supply unit 124 is provided with a fuel gas outlet communication hole 50 between the fuel gas supply communication hole 48 and the oxidant gas supply communication hole 52, and the fuel gas supply communication hole 48 and the fuel gas outlet communication hole. The holes 50 and the oxidant gas supply communication holes 52 are arranged along a direction intersecting the outer shape of the sandwiching portion 32.

  As shown in FIG. 12, the fuel gas supply passage 68 having one end communicating with the fuel gas supply communication hole 48 extends in one side portion 34 a of the bridge portion 34 and extends from the first connection portion 33 to the holding portion 32. And communicates with the two fuel gas supply holes 58. A fuel gas return passage 70 having one end communicating with the fuel gas lead-out communication hole 50 extends in the other side portion 34b of the bridge portion 34 and terminates in the sandwiching portion 32 from the first connecting portion 33. It communicates with the gas return hole 60.

  As shown in FIG. 13, the oxidant gas supply passage 74 whose one end communicates with the oxidant gas supply communication hole 52 extends in both sides 34 a and 34 b of the bridge part 34 and is sandwiched from the first connection part 33. It terminates in the section 32 and communicates with the two oxidant gas supply holes 82.

  In the third embodiment configured as described above, the reaction gas supply unit 124 is provided with the fuel gas outlet communication hole 50 between the fuel gas supply communication hole 48 and the oxidant gas supply communication hole 52. . Therefore, the fuel gas and the oxidant gas, which are supply gases, are heated by the high-temperature fuel gas that flows through the fuel gas passage 38 and moves through the fuel gas outlet communication hole 50. Therefore, the effect that heat self-sustainment is promoted and thermal efficiency is improved can be obtained.

  Further, the fuel gas supply communication hole 48, the fuel gas outlet communication hole 50, and the oxidant gas supply communication hole 52 are arranged along the direction intersecting the outer shape of the sandwiching portion 32. Thereby, the structure of the reactive gas supply part 124 is simplified and made compact. In addition, the same effects as those of the first embodiment can be obtained.

  In the third embodiment, a separator 122a shown in FIG. 14 can be provided instead of the separator 122 or in combination with the separator 122.

  In the separator 122a, the fuel gas supply passage 68 having one end communicating with the fuel gas supply communication hole 48 extends in the other side portion 34b of the bridge portion 34 and terminates in the sandwiching portion 32 from the first connecting portion 33. The two fuel gas supply holes 58 communicate with each other. A fuel gas return passage 70 having one end communicating with the fuel gas lead-out communication hole 50 extends in one side 34a of the bridge portion 34 and terminates in the first connecting portion 33 or the sandwiching portion 32. It communicates with the gas return hole 60. The separator 122a has the same effect as the separator 122 described above.

  FIG. 15 is a side view of a fuel cell stack 130 according to the fourth embodiment of the present invention.

  The fuel cell stack 130 includes a second load applying mechanism 132 that stacks the plurality of fuel cells 10 in the direction of arrow A and applies a load to the sandwiching portion 32 in the stacking direction. The second load applying mechanism 132 is employed instead of the weight member 108 of the first embodiment.

  A fixed plate member 138 is fixed to the end plate 90 via a plurality of bolts 134 and nuts 136. On the uppermost fuel cell 10, a pressing plate 140 having the same shape as the sandwiching portion 32 is disposed, and for example, two first receiving members 142 are mounted on the pressing plate 140. The first receiving member 142 is positioned and supported by the pressing plate 140 via pins 144.

  One end of the spring 146 contacts the first receiving member 142, while the other end of the spring 146 contacts the second receiving member 148. The second receiving member 148 is in contact with the tip of the pressing bolt 150, and the pressing bolt 150 is fixed to the fixing plate member 138 so that the position thereof can be adjusted.

  In the fourth embodiment configured as described above, a plurality of bolts 104 constituting the first load applying mechanism 98 are inserted into the pressing member 100 and screwed into the end plate 90, so that a desired portion 32 is provided in the clamping portion 32. A tightening load is applied. On the other hand, when the pressing bolt 150 constituting the second load applying mechanism 132 is screwed into the fixing plate member 138, a desired tightening load is applied to the sandwiching portion 32 and the electrolyte / electrode assembly 26 through the elastic force of the spring 146. Is granted.

  In addition, instead of the weight member 108 and the second load applying mechanism 132, for example, a member that expands by heat (a mixture of alumina fiber and vermiculite, etc.) is used as the second load applying mechanism. Can be used.

DESCRIPTION OF SYMBOLS 10, 120 ... Fuel cell 12, 130 ... Fuel cell sock 20 ... Electrolyte 22 ... Cathode electrode 24 ... Anode electrode 26 ... Electrolyte electrode assembly 28 ... Oxidant gas passage 30, 110, 122, 122a ... Separator 32, 112 ... Clamping part 33, 35 ... Connecting part 34, 114 ... Bridge part 36, 124 ... Reaction gas supply part 38 ... Fuel gas passage 40, 42, 44 ... Plate 46, 62, 76 ... Reaction gas supply member 48 ... Fuel gas supply communication Hole 50 ... Fuel gas outlet communication hole 52 ... Oxidant gas supply communication holes 54, 64, 78 ... Bridge members 56, 66, 80 ... Holding member 58 ... Fuel gas supply hole 60 ... Fuel gas return hole 68 ... Fuel gas supply passage 70 ... Fuel gas return passage 72 ... Reforming catalyst 74 ... Oxidant gas supply passage 82 ... Oxidant gas supply hole 84 ... Space 86 ... Sealing member 88 ... Oxidant gas Discharge passage 90 ... end plate 98,132 ... load applying mechanism 108 ... weight member

Claims (15)

An electrolyte / electrode assembly configured by sandwiching an electrolyte between an anode electrode and a cathode electrode is a fuel cell in which separators are stacked,
The separator sandwiches the electrolyte / electrode assembly and supplies a fuel gas along the electrode surface of the anode electrode, and an oxidant gas supplies an oxidant gas along the electrode surface of the cathode electrode. A sandwiching portion in which the agent gas passage is individually provided;
A fuel gas supply passage connected to the clamping portion for supplying the fuel gas to the fuel gas passage, a fuel gas return passage for returning the fuel gas flowing through the fuel gas passage, and an oxidant gas; A bridge portion in which an oxidant gas supply passage for supplying the oxidant gas passage is formed;
A fuel gas supply communication hole connected to the bridge portion for supplying the fuel gas to the fuel gas supply passage, a fuel gas discharge communication hole for deriving the fuel gas flowing through the fuel gas return passage, and Reactive gas supply portions in which oxidant gas supply communication holes for supplying the oxidant gas to the oxidant gas supply passage are respectively formed in the stacking direction;
With
The fuel cell according to claim 1, wherein the bridge portion circulates the entire outer periphery of the clamping portion integrally with the reaction gas supply portion.   2. The fuel cell according to claim 1, wherein at least one fuel gas supply hole for communicating the fuel gas passage and the fuel gas supply passage is provided in the clamping portion.   3. The fuel cell according to claim 1, wherein at least one oxidant gas supply hole for communicating the oxidant gas passage and the oxidant gas supply passage is provided in the sandwiching portion. Fuel cell.   4. The fuel cell according to claim 1, wherein at least one fuel gas return hole that connects the fuel gas passage and the fuel gas return passage is provided in the clamping portion. 5. A fuel cell. 3. The fuel cell according to claim 2, wherein at least one or more fuel gas return holes are provided in the sandwiching portion to connect the fuel gas passage and the fuel gas return passage.
The fuel cell, wherein the fuel gas return hole is disposed closer to the periphery of the clamping portion than the fuel gas supply hole. The fuel cell according to any one of claims 1 to 5, wherein a space portion is formed between an outer periphery of the sandwiching portion and an inner periphery of the bridge portion and the reactive gas supply portion,
The fuel cell according to claim 1, wherein the space portion constitutes an oxidant gas discharge communication hole for discharging the oxidant gas flowing through the oxidant gas passage. The fuel cell according to any one of claims 1 to 6, wherein the separator includes a first connecting portion that connects the sandwiching portion and the bridge portion;
A second connecting part for connecting the bridge part and the reactive gas supply part;
With
The fuel cell according to claim 1, wherein the first connecting portion and the second connecting portion are set at positions facing each other with the sandwiching portion interposed therebetween.   8. The fuel cell according to claim 1, wherein a reforming catalyst for reforming the fuel gas is disposed in at least a part of the fuel gas supply passage. Fuel cell.   9. The fuel cell according to claim 1, wherein the reactive gas supply unit includes the oxidant gas supply communication hole between the fuel gas supply communication hole and the fuel gas outlet communication hole. A fuel cell provided.   10. The fuel cell according to claim 9, wherein the fuel gas supply communication hole, the oxidant gas supply communication hole, and the fuel gas outlet communication hole are arranged along the outer shape of the clamping portion. battery.   9. The fuel cell according to claim 1, wherein the reaction gas supply unit includes the fuel gas outlet communication hole between the fuel gas supply communication hole and the oxidant gas supply communication hole. A fuel cell provided.   12. The fuel cell according to claim 11, wherein the fuel gas supply communication hole, the fuel gas outlet communication hole, and the oxidant gas supply communication hole are arranged along a direction intersecting an outer shape of the sandwiching portion. A fuel cell. The fuel cell according to any one of claims 1 to 12, wherein the clamping portion has a circular shape or an oval shape,
The fuel cell according to claim 1, wherein the bridge portion has a circular ring shape or an oval ring shape integrally with the reaction gas supply portion.   The fuel cell according to any one of claims 1 to 13, wherein the fuel cell is a solid oxide fuel cell.   15. The fuel cell according to claim 14, wherein the solid oxide fuel cell is a flat plate stacked solid oxide fuel cell.

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