JP2011204602A - Flat plate lamination type fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat lamination type fuel cell capable of enhancing follow-up performance for deformation of arm parts of upper and lower separators of a heat dissipation body, and exhibiting well-balanced power generation performance without occurrence of local smashed portions accompanying a lapse of operation against a power generation cell.SOLUTION: In the flat lamination type fuel cell, a plurality of power generation cells 1 and separators 7 are alternately laminated, gas manifolds 15, 16 are installed at a peripheral part of a laminate, the separator 7 has an interconnection part 7a in the center part and a flexible arm part 7b on the outside thereof, the tip of the arm part 7b is fixed to the gas manifold, and the heat dissipation body 30 is inserted between the interconnection of the upper and lower separators in the middle stage in the lamination direction of a stack. Between the upper face of the heat dissipation body 30 and the lower face of the interconnection part 7a of the separator 7 on the vertical upper side thereof and between the lower face of the heat dissipation body 30 and the upper face of the interconnection part 7b of the separator 7 on the vertical lower side thereof, contact resistance suppressing sheets 40 are arranged on the upper and lower faces, and foamed metal plates 42 are interposed between them, respectively.

Description

  The present invention relates to a flat plate type fuel cell in which a large number of power generation cells and separators are alternately stacked.

  Conventionally, a power generation cell having a structure in which a solid electrolyte layer made of an oxide ion conductor is sandwiched between an air electrode layer (cathode) and a fuel electrode layer (anode) from both sides is interposed with a separator having a reaction gas passage therebetween. In this state, a fuel cell stack is configured by stacking a large number of the fuel cell stacks, and a flat plate type fuel cell is known in which a load in the stacking direction is applied to the stack of fuel cell stacks.

  FIG. 2 shows a cross-sectional configuration of a main part of a conventional general flat plate type fuel cell, and a portion indicated by reference numeral 1 in the drawing is a power generation cell. In this power generation cell 1, a fuel electrode layer 3 is integrally formed on one surface of a solid electrolyte layer 2 serving as a support, and an air electrode layer 4 is integrally formed on the other surface.

  Here, the solid electrolyte layer 2 is made of a lanthanum gallate-based (LaGaO 3 -based) material having high oxygen ion conductivity, and has a thickness of about 200 μm. The fuel electrode layer 3 is made of a metal such as Ni or Co, or a cermet such as Ni—YSZ, Ni—SDC, Ni—GDC, Ni—SCSZ, or Co—YSZ, and the air electrode layer 4 is made of LaMnO 3, LaCoO 3. Etc. Incidentally, the fuel electrode layer 3 and the air electrode layer 4 are respectively formed on the surface of the solid electrolyte layer 2 with a thickness of 20 to 30 μm.

  Further, a fuel electrode current collector 5 made of a porous sintered metal plate such as a Ni-based alloy is disposed on the surface of the fuel electrode layer 3, and a porous material such as an Ag-based alloy is provided on the surface of the air electrode layer 4. An air electrode current collector 6 made of a sintered metal plate is provided.

  A single cell is formed by sandwiching the power generation cell 1 and the fuel electrode current collector 5 and the air electrode current collector 6 disposed on both sides of the power generation cell 1 with the separator 7, and a plurality of the single cells are stacked. Thus, a fuel cell stack (a flat plate type fuel cell) is configured.

  The separator 7 in this case is a plate having a function of electrically connecting the power generation cells 1 and supplying hydrogen-rich fuel gas (H 2, CO, etc.) and oxidant gas (air) to the power generation cells 1. It is in the form of a metal such as stainless steel. In this separator 7, as a two-system internal passage, the fuel gas introduced from the outer peripheral portion is discharged from the reaction gas discharge hole located at the substantially central portion of the surface facing the anode current collector 5. The oxidant gas flow path 9 for discharging the oxidant gas (air) introduced from the flow path 8 and another outer peripheral part from the reaction gas discharge hole located at the substantially central part of the surface facing the air electrode current collector 6. And are formed.

  In the flat plate type fuel cell having such a configuration, a large number of the power generation cells 1 configured by stacking the plurality of power generation elements described above are stacked via conductive members such as the separator 7 and the current collectors 5 and 6. Because of the structure, excellent adhesion between the components is required to ensure stable battery performance.For example, by tightening the fixing plates placed on the upper and lower ends of the stack together with bolts and nuts, In many cases, a structure is adopted in which a load is applied in the stacking direction to press-contact each component.

  However, especially when an internal manifold structure (a structure having a gas distribution manifold inside the fuel cell stack) is adopted, the power generation portion at the center in the planar direction of the stack and the manifold portion at the peripheral edge in the planar direction of the stack are stacked. Since the components are different from each other, if the manifold part and the power generation part are tightened together from the top and bottom using a clamping plate, both the edge and the center are tightened with the same amount of displacement by the rigid separator plate. As a result, the tightening force of each part may be excessive or insufficient due to the difference in height, etc., and as a result, the adhesion of each component may be impaired, or the power generation cell may be damaged due to excessive tightening force applied to the power generation part. Some problems occurred.

  Therefore, in view of such a problem, the applicant previously described in Japanese Patent Application Laid-Open No. 2004-228688 is a preferable flat plate stack type that can fasten both the manifold portion at the outer peripheral portion of the stack and the power generation portion at the central portion of the stack with a suitable load. A fuel cell is proposed. In addition, according to Patent Document 2, the applicant previously described a flat plate in which a radiator for dissipating heat generated in the stack to the outside is interposed between separators adjacent to the upper and lower sides of the intermediate stage in the stacking direction of the stack. A stacked fuel cell is also proposed.

  FIG. 3 shows an example of a previously developed product by the present applicant of a flat plate type fuel cell including the characteristic technical contents described in Patent Document 1 and Patent Document 2, respectively. The left figure shows the overall structure of the fuel cell stack, and the right figure shows an exploded and enlarged detail of the portion of the stack where the heat dissipator is interposed. FIG. 4 is a schematic partial side view as seen from the side of the stack, centering on the step with the radiator interposed. In the following description, FIG. 2 is also referred to for details.

  A fuel cell stack (flat plate type fuel cell) 100 shown in FIG. 3 is configured by arranging a fuel electrode layer 3 and an air electrode layer 4 on both surfaces of a solid electrolyte layer 2 as shown in detail in FIG. The power generation cell 1, the fuel electrode current collector 5 disposed outside the fuel electrode layer 3, the air electrode current collector 6 disposed outside the air electrode layer 4, and outside the current collectors 5, 6. A large number of unit cells (within the range shown in FIG. 2) composed of the separators 7 arranged are stacked.

  In addition, a fuel gas manifold 15 and an oxidant gas manifold 16 extending in the stack stacking direction (vertical direction) are formed in the vicinity of the outer periphery of the fuel cell stack 100, and the fuel gas manifold 15 includes the separators 7. The fuel gas passage 8 communicates, and the oxidant gas manifold 16 communicates with the oxidant gas passage 9 of each separator 7. During operation, fuel gas and oxidant gas (air) supplied from the outside are introduced into the manifolds 15 and 16, and each reaction gas is collected through the gas passages 8 and 9 of the separators 7. It is discharged to the electric current collector 5 side and the air electrode current collector 6 side, diffuses and moves inside the current collectors 5 and 6 and is guided to each electrode of each power generation cell 1 to generate a power generation reaction.

  As shown in FIG. 3, the separator 7 used here is composed of a substantially rectangular stainless steel plate having a thickness of several millimeters, and the power generation cell 1 and the current collectors 5 and 6 described above are laminated. A pair of interconnects 7a at the center of the plane extending from the outer peripheral edge of the central interconnect 7a so as to extend along the outer peripheral edge with a gap, and supporting the opposing edges of the interconnect 7a at two locations. And an elongated belt-like arm portion 7b. And in the state which laminated | stacked the separator 7 in the front-end | tip part (other end) 7c of each arm part 7b, the gas hole 7d penetrated in the plate | board thickness direction for each comprising the fuel gas manifold 15 and the oxidizing gas manifold 16 is formed. Has been.

  The gas hole 7d of one arm portion 7b communicates with the fuel gas passage 8 of the interconnect portion 7a through an internal passage (not shown) formed in the arm portion 7b, and the gas hole 7d of the other arm portion 7b Each of the power generation cells 1 is connected to the oxidant gas passage 9 of the interconnect portion 7a through an internal passage (not shown) formed in the arm portion 7b, and from each gas hole 7d through the gas passages 8 and 9. Fuel gas and oxidant gas can be supplied to the electrode surface.

  Single cells including the separator 7 having such a configuration are sequentially stacked with insulating manifold rings 11 and 12 interposed between the tip portions 7c of the arm portions 7b of the separator 7, and separators are formed on the upper and lower ends of the stacked body. A rectangular upper fastening plate 21 and a lower fastening plate 22 having a size larger than 7 are disposed, and the upper fastening plate 21 and the lower fastening plate 22 are arranged at two corners constituting the manifolds 15 and 16. In the vicinity, by tightening with bolts (tie rods), nuts 23, seat plates 24, etc., the gas holes 7d of the end portions 7c of the arm portions 7b and the manifold rings 11, 12 are mechanically caused by the tightening load. Adhering and joining. By this close contact / joining, the manifold rings 11 and 12 and each gas hole 7d of each separator 7 communicate with each other in the stacking direction, and the fuel gas manifold 15 excellent in gas sealing property extending in the stacking direction and the oxidation are formed inside the stack. An agent gas manifold 16 is formed. In addition, what is shown with the codes | symbols 25 and 26 in FIG. 3 is the inflow / outlet of the fuel gas manifold 15 and the oxidizing gas manifold 16 which were formed in the upper and lower clamping plates 21 and 22. FIG.

  In addition, a round hole 28 larger than the outer diameter of the power generation cell 1 is provided in the central portion of the upper fastening plate 21, and a weight 29 is placed in the round hole 28 via an insulating member. The center of the separator 7 (interconnect part 7a) is pressed in the stacking direction by the load of the weight 29, and a plurality of power generating elements constituting the single cell are brought into close contact with each other and fixed integrally. Since the fuel electrode current collector 5 and the air electrode current collector 6 interposed between the separators 7 are sponge-like porous sintered metal, these sponge-like members are elastically deformed by the load of the weight 29, The upper and lower separators 7 are pressed and clamped with a certain degree of elasticity. Thus, when the load by the weight 29 is used as a weighting means for the laminated body (power generation cell 1), thermal expansion and contraction of the stack constituent members (power generation cell 1, current collectors 5, 6 and separator 7) in the thermal cycle. Therefore, a constant surface pressure can always be applied to the power generation cell 1, and stable battery performance (output power) that does not cause variations in the cell voltages can be ensured.

  Further, since each separator 7 has a predetermined flexibility that allows each arm portion 7b to be displaced in the stacking direction, the load in the stacking direction applied to the separator 7 is applied to the manifolds 15 and 16 and the interconnect portion 7a. Accordingly, it is possible to absorb the difference in height between the manifolds 15 and 16 and the interconnect portion 7a, and to fasten them to each other with a suitable load.

  For example, the load due to the weight 29 in the stacking direction applied to the fuel cell stack 100 (the load on the interconnect portion 7a of the separator 7 at the center of the stack) determines the electrical contact of each power generating element in consideration of damage to the stack constituent members. It is preferable to set the minimum necessary amount, and the load is set to about several kgf. On the other hand, the load applied to each of the manifolds 15 and 16 is currently set to about several hundred kgf in order to ensure the sealing performance of the manifolds 15 and 16.

  By the way, in the flat plate type fuel cell stack 100 described above, it is found that the cell temperature (separator temperature) of the middle stage of the stack tends to become extremely higher than the cell temperature of the stack end as the number of stacks increases. ing. This is mainly due to the fact that the fuel cell stack 100 has a laminated structure, so that heat dissipation at the middle stage is poor compared to both ends and it is difficult for the Joule heat generated during power generation to be dissipated outside the cell. . When a temperature difference occurs in the stacking direction of the fuel cell stack 100, the concentration of the circulating gas decreases in the high-temperature part, and the uniform distribution of the reaction gas to each power generation cell collapses, resulting in nonuniform cell voltage. become. In a fuel cell stack configured by connecting a large number of power generation cells in series, if such voltage non-uniformity occurs in each power generation cell, the total output of the fuel cell is limited by some low voltage cells. As a result, there is a possibility that efficient power generation cannot be performed.

  Therefore, in the fuel cell stack 100 shown in FIGS. 3 and 4, the radiator 30 is provided between the separators 7 adjacent to each other in the middle of the stacking direction in the stacking direction in order to release heat generated in the stack to the outside. It is arranged.

  The heat dissipating body 30 is made of a metal having excellent thermal conductivity. For example, as shown in FIG. 4, a plurality of cylindrical support portions 35 and a plurality of protrusions radially projecting from the peripheral side surfaces of the support portions 35 are provided. A plurality of heat dissipating plate members (heat dissipating fins) 36, and upper and lower flange portions 31 and 32 provided at both upper and lower ends of the support portion 35, and the support portion 35 extends in the plane direction of the fuel cell stack 100. It is arrange | positioned so that it may be located in the approximate center.

  The upper flange portion 31 and the lower flange portion 32 are disposed in close contact with each other between the separators 7 adjacent to each other in the vertical direction, so that good electrical contact with the adjacent separators 7 is achieved. Can be obtained. At this time, as shown in FIG. 5 (a), in order to reduce the contact resistance between the radiator 30 and the separator 7, a silver sheet (contact resistance suppression sheet) 40 is provided between the contact surfaces of the radiator 30 and the separator 7. Intervene.

  The support portion 35 mainly serves as a cell current path and supports a load in the stacking direction applied to the upper flange portion 31. By disposing the support portion 35 substantially at the center in the stack surface direction, the stack current concentrated in the center of the power generation cell 1 and flowing in the stacking direction can be efficiently relayed to the next power generation cell 1. The support portion 35 may be solid or hollow, and in the case of being hollow, for example, it is preferable that a large number of holes for releasing a heat reservoir generated in the hollow portion to the outside are provided in the peripheral wall. . Further, since the heat radiation fins 36 are provided radially around the support portion 35, the fluidity of the exhaust gas can be improved around the heat radiation fins 36, so that the heat radiation effect by the heat radiation fins 36 can be expected to be improved.

  As described above, when the radiator 30 is disposed in an intimately integrated manner between the separators 7 and 7, the Joule heat from the power generation cell 1 at the middle stage of the stack where the temperature inside the stack tends to be relatively high. Can be thermally conducted from the entire surface of the adjacent separator 7 to efficiently radiate heat from the heat radiation fins 36. As a result, the temperature difference across the stacking direction can be reduced so that the temperature of the stack middle stage approaches the temperature of the stack upper and lower stages, thereby achieving a uniform temperature distribution in the stack stacking direction. Thus, the voltage distribution in each power generation cell 1 can be suppressed, and the temperature of the entire stack can be maintained within a predetermined temperature range suitable for the power generation reaction temperature. Therefore, efficient power generation that is not restricted by some low-voltage cells can be performed, and damage to the power generation cell 1 such as peeling of the electrode layers 3 and 4 due to thermal stress that easily occurs at high temperatures can be prevented. The durability (thermal cycle characteristics) of the battery can be improved.

  Note that the upper separator 7 in contact with the upper flange portion 31 of the heat radiating body 30 is of a type having no oxidant gas discharge hole because the power generation cell 1 is not provided on the lower surface side thereof. In addition, the lower separator 7 in contact with the lower flange portion 32 of the heat radiating body 30 has no power generation cell 1 on its upper surface side, so that a type without a fuel gas discharge hole is used.

JP 2008-218278 A JP 2006-222074 A

  By the way, as in the fuel cell stack 100 described above, the separator 7 is formed by being divided into an interconnect portion 7a that is a power generation portion and a flexible arm portion 7b, and the tips of the interconnect portion 7a and the arm portion 7b, respectively. When the supporting and fixing conditions of the portion 7c are different, the thickness of the current collectors 5 and 6 is reduced due to creep deformation under a high temperature load and the stack height is reduced under high temperature conditions during power generation accompanying operation. Even so, the arm portion 7b of the separator 7 is elastically deformed, so that the interconnect portion 7a is displaced to a position lower than a portion where the manifolds 15 and 16 are located. For example, even in the initial state as shown in FIG. 5A, as the operation progresses, the central interconnect portion 7a is displaced to a position lower than a portion of the manifolds 15 and 16, and the separator 7 The arm portion 7b bends accordingly.

  Thus, when the heat sink 30 is not interposed when the central portion of the laminated body (the portion where the interconnect portion 7a of the separator 7 is located) is displaced, the distal end portion 7c of the arm portion 7b of the separator 7 of each layer is fixed. Even if it is done, it can be considered that the condition of elasticity (rigidity in the laminating direction) of the arm portion 7b is uniform in all layers, so even if the lower layer portion is displaced to a lower position, the upper layer follows and displaces. By doing so, no problem arises. However, in the case of the fuel cell stack 100 as shown in FIG. 3, a member having a different rigidity condition such as the heat radiating body 30 (in this case, other than the heat radiating body 30 may be used as the “interposing body”). In the figure, that is, the range from the upper separator 7 to the radiator 30 to the lower separator 7 is an integral part (equivalent to a separator). It shows the rigidity as. That is, the elasticity of the arm portions 7b of the two upper and lower separators 7 is exhibited by addition (the arm portions 7b of the two separators 7 exhibit twice the rigidity of the other layers). 5B, the arm portion 7b of the separator 7 below the separator 7 on the lower surface of the radiator 30 (the separator sandwiching the power generating cell 1 between the separator 7 on the lower surface of the radiator 30) is shown in FIG. In the case of deformation as shown in D, the arm portion 7b of the upper separator 7 becomes difficult to displace following the lower layer as shown by B in the figure, and as a result, a large crushing portion C becomes a single layer in the lower layer. It has been found that it occurs locally in the cell plane and may cause problems in power generation performance due to lack of plane balance.

  In consideration of the above circumstances, the present invention is configured such that a heat dissipating body (intervening body) having higher rigidity in the stacking direction than that of the power generation cell is sandwiched between specific layers of the stack. Even if there is a place where there is a difference in the property), the followability of the deformation of the arm part of the separator can be improved, and a locally crushed place with respect to the power generation cell with the progress of operation can be generated An object of the present invention is to provide a flat plate type fuel cell that can exhibit a well-balanced power generation performance.

  In order to solve the above problems, the invention according to claim 1 is configured such that a fuel cell stack is configured by alternately stacking a plurality of power generation cells and separators each having a reaction gas passage therein, and the fuel cell. A fuel gas manifold and an oxidant gas manifold that communicate with the gas passages of the separators and communicate with each other in the stacking direction are provided on the outer peripheral portion of the stack constituting the stack, and the separator has the power generation cell at the center. A pair of arm portions having an interconnect portion disposed and extending from an edge portion of the interconnect portion on the outside of the interconnect portion and connected to the fuel gas manifold and the oxidant gas manifold. In addition, each arm portion is provided with flexibility to be displaceable in the stacking direction, A load in the stacking direction is applied to the stack portion of the interconnect portion and the power generation cell, and further, the interconnect portion of the upper separator and the lower separator adjacent to each other in the middle portion of the fuel cell stack in the stacking direction. In a flat plate type fuel cell in which an intermediate body having rigidity higher in the stacking direction than the power generation cell is inserted between the interconnect sections, the interconnect section of the upper surface of the intermediate body and the separator immediately above it Between the lower surface of the interposer and between the lower surface of the interposer and the upper surface of the interconnect portion of the separator immediately below the metal plate, a metal foam plate is interposed between the upper and lower surfaces of the contact resistance suppression sheet. It is characterized by this.

  The invention according to claim 2 is the flat plate type fuel cell according to claim 1, wherein the interposer is a radiator that releases heat generated by the fuel cell stack to the outside. It is a feature.

  According to a third aspect of the present invention, there is provided a flat plate type fuel cell according to the second aspect, wherein the heat dissipator mainly serves as a cell current path and supports a load in the stacking direction. The upper and lower flange portions that are provided at the upper and lower ends of the support portion to obtain contact with the adjacent separator, and the heat dissipating plate member 3, and the upper surface of the upper flange portion of the radiator and the upper side thereof The contact resistance suppression sheets are arranged on the upper and lower surfaces between the lower surface of the interconnect portion of the separator and between the lower surface of the lower flange portion of the heat radiator and the upper surface of the interconnect portion of the separator immediately below the separator. Above, the said metal foam board is each interposed, It is characterized by the above-mentioned.

  In the first aspect of the present invention, even when an intermediate body having greater rigidity in the stacking direction than the power generation cells is inserted in the intermediate stage of the fuel cell stack, Since the foam metal plates having the property of being crushed flexibly are inserted between the separator and the interposer, the upper and lower separator arm portions of the interposer are deformed by the flexible deformation of the foam metal plates. Can be easily displaced by following the arm portions of the separators of the other layers. Therefore, a well-balanced power generation performance can be exhibited over a long period of time without causing a local collapsed portion with respect to the power generation cell as the operation progresses. Further, merely inserting the foam metal plate between the upper and lower separators and the interposition body may increase the contact resistance between the contact surfaces of the separator, the foam metal plate, and the interposition body. Since a contact resistance suppression sheet (for example, a silver sheet) is arranged on the upper and lower surfaces, the contact resistance suppression sheet covers the surface of the separator and the interposer, thereby reducing surface oxidation. In addition, it is possible to effectively suppress an increase in contact resistance between the foam metal plate and the separator and between the foam metal plate and the interposition body.

  In the invention according to claim 2, when one or a plurality of heat dissipating members are inserted in the middle stage of the stack as an interposer, two layers of separators overlap each other in the layer in which the heat dissipating member is inserted. However, the rigidity of the separator arm part was better overall, and the followability of the separator arm part could be worse than other layers, but it had the property of being crushed flexibly between the radiator and the upper and lower separators. Since the foam metal plate is inserted, the possibility can be eliminated. Moreover, since the contact resistance suppression sheet | seat (for example, silver sheet) is distribute | arranged to the upper and lower surfaces of a metal foam board, the increase in contact resistance can also be suppressed.

  In the invention according to claim 3, the heat dissipator mainly serves as a path for the cell current and supports the columnar support portions for supporting the load in the stacking direction, and the contact between the upper and lower ends of the support portions and the adjacent separator. The upper and lower flange portions and the heat radiating plate member are provided between the upper surface of the upper flange portion of the heat radiating member and the lower surface of the interconnect portion of the separator immediately above, and the lower side of the heat radiating member. Between the lower surface of the flange part and the upper surface of the interconnect part of the separator immediately below it, a metal sheet is interposed between the contact resistance suppression sheets on the upper and lower surfaces, so the part that sandwiches the heat sink However, since a metal foam plate with contact resistance suppression sheets on the upper and lower surfaces is interposed between the radiator and the interconnect parts of the upper and lower separators. By flexibly deforming the metal foam plate, the upper and lower separator arm portions of the radiator can be easily displaced following the other layer separator arm portions. The power generation performance with good balance can be demonstrated for a long time without causing any local crushing points to the power generation cell, and between the metal foam plate and the separator and between the metal foam plate and the heat dissipation by arranging the metal foam plate. An increase in contact resistance between bodies can be effectively suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic partial side view seen from the side of a stack centering on the step | paragraph which interposed the heat radiator in the fuel cell of embodiment of this invention, (a) shows the first state before starting an operation | movement. FIG. 2B is a diagram illustrating a state after a predetermined test time has elapsed after starting operation. It is a figure which shows the principal part cross-section structure of the conventional general flat laminated fuel cell. It is a figure which shows the example of the flat laminated fuel cell which this applicant developed previously, the figure on the left side shows the whole structure of a fuel cell stack, and the figure on the right side interposes the radiator of the middle stage of the stack. The details of the parts are disassembled and enlarged. FIG. 4 is a schematic partial side view as seen from the side of the stack, centering on the step in which the heat radiating body is interposed in FIG. 3. It is the schematic partial side view seen from the side of a stack centering on the step which interposed the heat radiator, (a) is a figure showing the first state before starting operation, and (b) starts operation. It is a figure which shows the state after passing predetermined test time.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
The basic configuration of the flat plate type fuel cell of the present embodiment is almost the same as that described above with reference to FIGS. 2 to 4, and the different points, that is, the feature points are shown in FIG. As shown in FIG. 3, between the upper surface of the upper flange portion 31 (see FIG. 3) of the radiator 30 and the lower surface of the interconnect portion 7a of the separator 7 immediately above it, and the lower flange portion 32 (see FIG. 3) and a silver sheet 40 as a contact resistance suppressing sheet on the upper and lower surfaces between the upper surface of the interconnect portion 7a of the separator 7 immediately below the lower surface, and a silver foam metal plate 42 is interposed between the upper and lower surfaces. It was made to. The foam metal plate 42 is also called a porous sintered metal plate, has a three-dimensional network structure, and has a property of being crushed flexibly. The other configurations are the same and will not be described.

When such a metal foam plate 42 is interposed, the following effects can be obtained.
That is, when one or more radiators 30 are inserted in the intermediate stage of the fuel cell stack 100, two separators 7 overlap each other in the layer in which the radiator 30 is inserted. Although the rigidity of 7b was better as a whole and the followability of the arm portion 7b of the separator 7 was likely to be worse than the other layers, it has the property of being crushed flexibly between the radiator 30 and the upper and lower separators 7 By inserting the foamed metal plate 42, the foamed metal plate 42 is flexibly deformed, so that the arm portions 7b of the upper and lower separators 7 of the radiator 30 are replaced with the arm portions 7b of the separators 7 of the other layers. As a result, it can be easily displaced, and as a result, a well-balanced power generation performance can be exhibited for a long time without causing a local crushing portion with respect to the power generation cell 1 as the operation progresses. It is possible. Further, the contact surfaces of the upper separator 7 to the metal foam plate 42 to the heat radiator 30 to the metal foam plate 42 to the lower separator 7 are simply inserted between the upper and lower separators 7 and the heat radiator 30. The contact resistance suppression sheet 40 is disposed between the separator 7 and the radiator 30 because the contact resistance suppression sheet (silver sheet) 40 is disposed on the upper and lower surfaces of the metal foam plate 42. By covering the surface, it is possible to reduce the oxidation of the surface, thereby effectively suppressing an increase in contact resistance between the metal foam plate 42 and the separator 7 and between the metal foam plate 42 and the radiator 30. Can do.

  In the above embodiment, the case where the interposed body is a radiator is described. However, when a member incorporating a thermocouple is inserted in a specific layer, or a layer incorporating another interposed body is in the stack. In this case, the same problem may occur. Therefore, the present invention can be applied to such a case. Moreover, a shape and a type are not ask | required also when the heat radiator is incorporated.

DESCRIPTION OF SYMBOLS 1 Power generation cell 7 Separator 7a Interconnect part 7b Arm part 7c Tip part 100 Fuel cell stack 8 Fuel gas path 9 Oxidant gas path 15 Fuel gas manifold 16 Oxidant gas manifold 30 Heat dissipator
31 Upper flange 32 Lower flange 35 Support part 36 Heat radiating plate member (radiating fin)
40 Contact resistance suppression sheet (silver sheet)
42 Foam metal sheet

Claims (3)

A fuel cell stack is configured by alternately stacking a plurality of power generation cells and separators each having a reaction gas passage therein, and the gas passages of the separators are disposed on the outer peripheral portion of the stack constituting the fuel cell stack. A fuel gas manifold and an oxidant gas manifold that communicate with each other in the stacking direction are provided, and the separator has an interconnect portion in which the power generation cell is disposed in a central portion, and outside the interconnect portion. The interconnect portion has a pair of arm portions that extend from the edge portion and are connected to the fuel gas manifold and the oxidant gas manifold, and each arm portion has a pair of arm portions in the stacking direction. Flexibility to be displaceable is given, and it is laminated on the laminated part of the interconnect part and power generation cell Is applied between the interconnect portion of the upper separator and the interconnect portion of the lower separator adjacent to each other in the middle portion of the fuel cell stack in the stacking direction. In a flat plate type fuel cell in which an interposed body having a large rigidity in the stacking direction is inserted,
A contact resistance suppression sheet is provided between the upper surface of the interposer and the lower surface of the interconnect portion of the separator immediately above it, and between the lower surface of the interposer and the upper surface of the interconnect portion of the separator immediately below it. A flat plate type fuel cell characterized in that foam metal plates are interposed on upper and lower surfaces, respectively.   2. The flat plate type fuel cell according to claim 1, wherein the interposer is a heat radiating body that releases heat generated by the fuel cell stack to the outside. 3.   The heat radiator is mainly a path for cell current and supports column-shaped support portions that support the load in the stacking direction, upper and lower flange portions that are provided at both upper and lower ends of the support portions to obtain contact with adjacent separators, and heat dissipation Plate, and between the upper surface of the upper flange portion of the radiator and the lower surface of the interconnect portion of the separator immediately above it, and the lower surface of the lower flange portion of the radiator and immediately below it 3. The flat plate laminate according to claim 2, wherein the metal foam plate is interposed between the upper surface of the interconnect portion of the separator on the upper side and the contact resistance suppressing sheet on the upper and lower surfaces. 4. Type fuel cell.