JP5346402B1 - Fuel cell and fuel cell stack - Google Patents

Abstract

Provided are a fuel cell and a fuel cell stack capable of maintaining good electrical connectivity even during long-term use.
A cell body 20 having electrodes 14 and 15 formed on both surfaces of an electrolyte 2 is disposed between a pair of interconnectors (hereinafter referred to as ICs) 12 and 13, and is disposed between the electrode 15 and the IC 13. A fuel battery cell 3 including a current collecting member 190 that electrically connects both of them, and the current collecting member 190 is a cell that contacts a connector abutting portion 190a that abuts on the IC 13 and an electrode 15 of the cell body 20. A main body abutting portion 190b and a connecting portion 190c that connects the connector abutting portion 190a and the cell main body abutting portion 190b are formed in series, and the spacer is disposed between the connector abutting portion 190a and the cell main body abutting portion 190b. The current collecting member 190 and the spacer 580 are elastic in the direction in which the distance between the cell body 20 and the IC 13 is increased, and the elastic amount of the spacer 580 is larger than the elastic amount of the current collecting member 19.
[Selection] Figure 5

Description

  In the present invention, two electrodes are provided on both surfaces of an electrolyte layer, and fuel gas is supplied to one electrode (hereinafter referred to as a fuel electrode) and an oxidant gas is supplied to the other electrode (hereinafter referred to as an air electrode). The present invention relates to a fuel cell that generates power and a fuel cell stack in which a plurality of the fuel cells are stacked and fixed.

  Conventionally, as described in, for example, Patent Document 1, a cell body having a pair of interconnectors and an air electrode formed on one surface of an electrolyte and a fuel electrode formed on the other surface between the interconnectors And a current collecting member that is disposed between the air electrode and the interconnector or between the fuel electrode and the interconnector and electrically connects the air electrode and the interconnector or the fuel electrode and the interconnector. is there.

  The current collecting member of this fuel cell has a structure in which an elastic member having a claw-like conductivity is cut and raised from a flat plate-like current collecting plate. The flat surface of the current collecting plate is joined to the interconnector and is electrically conductive. The tip of the elastic member having the property is brought into contact with the cell main body to make electrical connection.

JP 2009-266533 A

  As in the prior art, the current collecting member brought into contact with the cell body by the elasticity of the elastic member having conductivity is plastically deformed over a long period of use, and the strength of the elastic member having conductivity due to high heat during power generation is reduced. Furthermore, the contact force for obtaining the planned electrical connection may not be obtained because the elastic member having conductivity is affected by creep deformation. In such a case, the conductive elastic member cannot follow the deformation of the cell body due to temperature cycle, fuel pressure / air pressure fluctuation, etc., and contact becomes uncertain, and the air electrode and the interconnector or fuel electrode The electrical connection of the interconnector may be uncertain.

  In addition, when the above-described factors for decreasing the contact force for obtaining the electrical connection of the elastic member are combined, the portion of the elastic member that should contact the cell body may contact the interconnector side in reverse. . On the other hand, the current collecting member is often formed of a material excellent in bondability with the interconnector because the flat surface is bonded to the interconnector. For this reason, when an elastic member contacts the interconnector side in the high temperature environment at the time of electric power generation, it may join by sintering. Then, since the elastic member is integrated with the interconnector, it is difficult to make contact with the cell body, and there is a fear that the electrical connection between the air electrode and the interconnector or the fuel electrode and the interconnector becomes uncertain.

  The present invention has been made in view of the above, and an object thereof is to provide a fuel cell and a fuel cell stack capable of maintaining good electrical connectivity even during long-term use.

To achieve the above object, the present invention provides a pair of interconnectors as set forth in claim 1,
A cell body having electrodes formed on the upper and lower surfaces of the plate-like electrolyte, spaced apart from each of the interconnectors,
A fuel cell comprising: a current collecting member disposed between at least one of the electrodes and the interconnector, and electrically connecting the electrode and the interconnector,
The current collecting member includes a connector abutting portion that abuts on the interconnector, a cell body abutting portion that abuts on the electrode of the cell body, and a connecting portion that connects the connector abutting portion and the cell body abutting portion. And are formed in a series,
Having a spacer disposed between the connector contact portion and the cell body contact portion;
The current collecting member and the spacer have elasticity in a direction in which the distance between the cell main body and the interconnector increases, and the elastic amount of the spacer provides a fuel cell that is larger than the elastic amount of the current collecting member.

  Here, “elasticity” is a property of an object that deforms when an external force is applied, and returns to its original state when the external force is removed. When a load in the thickness direction is applied to the sample under the same conditions, and the load is removed, the elastic amount increases as the displacement amount in the thickness direction increases, and conversely, the elasticity decreases as the displacement amount in the thickness direction decreases. Means small amount.

  Further, as described in claim 2, the connecting portion is bent at about 180 degrees, and the connector contact portion and the cell body contact portion are disposed on both sides of the spacer. A fuel cell is provided.

Further, as described in claim 3, a pair of interconnectors;
A cell body having electrodes formed on the upper and lower surfaces of the plate-like electrolyte, spaced apart from each of the interconnectors,
A fuel cell comprising: a current collecting member disposed between at least one of the electrodes and the interconnector, and electrically connecting the electrode and the interconnector,
The current collecting member includes a connector abutting portion that abuts on the interconnector, a cell body abutting portion that abuts on the electrode of the cell body, and a connecting portion that connects the connector abutting portion and the cell body abutting portion. And are formed in a series,
A spacer disposed between the connector contact portion and the cell body, and between the cell body contact portion and the interconnector;
The current collecting member and the spacer have elasticity in a direction in which the distance between the cell main body and the interconnector increases, and the elastic amount of the spacer provides a fuel cell that is larger than the elastic amount of the current collecting member.

Moreover, as described in claim 4, a pair of interconnectors;
A cell body having electrodes formed on the upper and lower surfaces of the plate-like electrolyte, spaced apart from each of the interconnectors,
A fuel cell comprising: a current collecting member disposed between at least one of the electrodes and the interconnector, and electrically connecting the electrode and the interconnector,
The current collecting member includes a connector abutting portion that abuts on the interconnector, a cell body abutting portion that abuts on the electrode of the cell body, and a connecting portion that connects the connector abutting portion and the cell body abutting portion. And are formed in a series,
Between the connector contact portion and the cell body, or between the cell body contact portion and the interconnector, has a spacer disposed,
The current collecting member and the spacer have elasticity in a direction in which the distance between the cell main body and the interconnector increases, and the elastic amount of the spacer provides a fuel cell that is larger than the elastic amount of the current collecting member.

  In addition, as described in claim 5, the spacer is at least one of mica, alumina felt, vermiculite, carbon fiber, silicon carbide fiber, and silica. A fuel cell is provided.

In addition, as described in claim 6, further comprising a fastening member that laminates the interconnector, the cell body, and the current collecting member and fastens them together.
The clamp member and the spacer are pressed so that the cell main body contact portion of the current collecting member contacts the cell main body and the connector contact portion contacts the interconnector. A fuel cell according to any one of the above items is provided.

  Moreover, as described in claim 7, the spacer provides the fuel cell according to claim 6, which has a higher coefficient of thermal expansion in the tightening direction than the tightening member.

  Moreover, as described in Claim 8, the said current collection member is a product made from a porous metal, a metal-mesh, a wire, or a punching metal, The fuel cell of any one of Claims 1-7 is provided.

  Moreover, as described in claim 9, the cell main body contact portion of the current collecting member is bonded to a surface of the at least one electrode of the cell main body. The fuel cell described in 1. is provided.

  Further, as described in claim 10, the fuel battery cell according to any one of claims 1 to 9, wherein the connector contact portion of the current collecting member is joined to the interconnector. .

  Further, as described in claim 11, the current collecting member is formed so as to be freely bendable and stretchable in a direction intersecting with the surface direction of the current collecting member and hardly generate a repulsive force against bending and stretching. The fuel battery cell according to any one of 10 to 10.

  Moreover, as described in Claim 12, the said current collection member is arrange | positioned between a fuel electrode and the said interconnector, and is a product made from Ni or Ni alloy. A fuel cell is provided.

  Moreover, as described in claim 13, a fuel cell stack is provided in which a plurality of the fuel cells according to any one of claims 1 to 12 are stacked and fixed by the fastening member.

  According to the fuel cell according to claim 1 or 2, since the spacer enters between the connector abutting portion and the cell main body abutting portion of the current collecting member to prevent the contact between the two, high heat during fuel generation (fuel cell) There is no fear that the connector contact portion and the cell body contact portion are joined by sintering. Therefore, it is possible to prevent the connector contact portion and the cell body contact portion from being integrated (joining by sintering), and eventually the instability of electrical contact associated therewith.

  According to the fuel cell of the third aspect, since the spacer enters between the connector abutting portion of the current collecting member and the cell main body and the cell main body abutting portion and the interconnector to prevent the contact between them, There is no fear that the connector contact portion and the cell body and the cell body contact portion and the interconnector are joined by sintering due to high heat. Therefore, it is possible to prevent the connector contact portion and the cell main body and the cell main body contact portion and the interconnector from being integrated (joining by sintering), and thereby causing unstable electrical connection.

  According to the fuel cell of claim 4, since the spacer enters between the connector abutting portion of the current collecting member and the cell main body or the cell main body abutting portion and the interconnector to prevent the contact therebetween, Therefore, there is no fear that the connector abutting portion and the cell body or the cell body abutting portion and the interconnector are joined by sintering. Therefore, the connector abutting portion, the cell body or the cell body abutting portion and the interconnector are integrated (sintered). This can prevent electrical connection from becoming unstable.

Furthermore, according to the fuel battery cell according to claims 1 to 4.
(I) When the cell body etc. is deformed by a thermal cycle and the interval between the interconnector and the electrode is expanded, that is, when the space where the current collecting member is installed is expanded, the elastic amount of the spacer is large. The electrical connection between the interconnector and the electrode is stabilized. Further, even when the space where the current collecting member is once reduced and then the space is enlarged, the elastic amount of the spacer is larger than that of the current collecting member, so that the electrical connection between the interconnector and the electrode Can be stabilized.
(Ii) Since the spacer is flexible in the compression direction, there is no possibility that the repulsive force from the spacer acts excessively to induce cracking of the cell body. That is, the spacer exhibits cushioning properties, and stress concentration (with respect to the cell main body) generated by the tightening force during assembly is suppressed, and cell cracking can be reduced.

  The spacer as described above can be formed by using at least the material described in claim 5.

  In addition, according to the fuel cell of the sixth aspect, the interconnector, the cell main body, and the current collecting member are stacked and tightened with the fastening member, so that the current collecting member contacts the cell main body due to the elasticity of the spacer. Since the portion abuts reliably with the cell body or the connector abutment portion abuts reliably with the interconnector, the electrical contact of the current collecting member is stabilized.

  Further, according to the fuel cell of claim 7, since the coefficient of thermal expansion in the tightening direction of the spacer is higher than that of the tightening member, the tightening member is thermally expanded by the heat generated during power generation. Even if the tightening force for tightening the main body and the current collecting member is reduced, the spacer is thermally expanded further, so that the pressing action on the current collecting member is maintained.

  In addition, as described in claim 8, if the current collecting member is formed of a porous metal, a metal mesh, a wire, or a punching metal, the diffusibility of the fuel gas and the oxidant gas is improved as compared with the case of forming a simple plate material. improves.

  In addition, as described in claim 9, when the cell main body contact portion is joined to the surface of at least one electrode of the cell main body, deformation of the cell main body due to temperature cycle, fuel pressure / air pressure fluctuation, etc. On the other hand, since the cell main body contact portion is integrated and follows, a stable electrical connection can be obtained.

  In addition, as described in claim 10, if the connector contact portion of the current collecting member is joined to the interconnector, the connector can be used even if the cell body is deformed due to temperature cycle, fuel pressure / air pressure fluctuation, etc. The electrical connection between the contact portion and the interconnector can be continued stably.

  In addition, as described in claim 11, if the current collecting member is bent and stretched in a direction intersecting with the surface direction of the current collecting member and hardly causes a repulsive force against bending and stretching, the temperature cycle and the fuel pressure are increased.・ As the division of roles becomes clear such that the spacer responds to deformation of the cell body due to fluctuations in air pressure, etc., and the current collecting member corresponds to electrical connection, it is optimal for each role Material and shape can be selected.

Further, as described in claim 12, if the current collecting member is disposed between the electrode corresponding to the fuel gas and the interconnector and is formed of Ni or Ni alloy, the fuel cell is heated after being assembled. Only the cell main body contact portion and the connector contact portion of the current collecting member can be joined to the electrode and the interconnector.
In other words, Ni or Ni alloy is superior in bonding property to the electrode corresponding to the fuel gas and the interconnector due to its material, and the cell main body contact portion and connector contact portion of the current collecting member are mainly elastic of the spacer. Since the cell body and the interconnector are reliably in contact with each other, the cell body contact part diffuses and joins with the Ni in the electrode of the cell body when heated after the assembly is completed, or the connector contact part becomes the interconnector. Diffusion bonding and unity. As described above, when the cell main body contact portion and the connector contact portion are joined and integrated with the cell main body and the interconnector, the electrical connection between the cell main body and the interconnector is stabilized.
In addition, since the temperature at the time of power generation of the fuel cell reaches about 700 ° C. to 1000 ° C., it is possible to join the cell main body contact portion and the connector contact portion to the electrode side cell main body and interconnector by heat during power generation. it can. Therefore, energy can be saved by omitting the step for heating.

  Moreover, since the fuel cell stack described in claim 13 is formed by stacking a plurality of the fuel cells according to any one of claims 1 to 12 and fixing them with a fastening member, even in long-term use. Good electrical connectivity can be maintained.

It is a perspective view of a fuel cell. It is a perspective view of a fuel cell. It is a disassembled perspective view of a fuel cell. It is a disassembled perspective view of the fuel battery cell which narrowed down decomposition parts. It is the longitudinal cross-sectional view which abbreviate | omitted the middle of the fuel cell. It is a longitudinal cross-sectional view which decomposes | disassembles and shows FIG. It is the sectional view on the AA line of FIG. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is a perspective view of a current collection member. (A) is a perspective view of a spacer, (b) is a perspective view before mounting the spacer of a current collection member. It is a perspective view of the current collection member which shows the modification of FIG.10 (b). It is a graph which shows the relationship between a load and a displacement amount about a current collection member and a spacer. It is the longitudinal cross-sectional view which abbreviate | omitted the middle of the fuel battery cell which concerns on another form. It is the longitudinal cross-sectional view which abbreviate | omitted the middle of the fuel battery cell which concerns on another form. It is the longitudinal cross-sectional view which abbreviate | omitted the middle of the fuel battery cell which concerns on another form. It is the longitudinal cross-sectional view which abbreviate | omitted the middle of the fuel battery cell which concerns on another form.

Currently, fuel cells are roughly classified according to the material of the electrolyte. The polymer electrolyte membrane is used as a polymer electrolyte fuel cell (PEFC), the phosphoric acid fuel cell (PAFC) using phosphoric acid as an electrolyte, and Li- There are four types: a molten carbonate fuel cell (MCFC) using Na / K carbonate as an electrolyte and a solid oxide fuel cell (SOFC) using ZrO ₂ ceramic as an electrolyte, for example. Each type has a different operating temperature (the temperature at which ions can move through the electrolyte). At present, PEFC is at room temperature to about 90 ° C, PAFC is about 150 ° C to 200 ° C, and MCFC is about 650 ° C to 700 ° C. , SOFC is about 700 ° C to 1000 ° C.

[Embodiment 1]
The fuel cell 1 of Embodiment 1 shown in FIGS. 1 to 11 is an SOFC using, for example, a ZrO ₂ -based ceramic as an electrolyte 2. The fuel cell 1 includes a fuel cell 3 that is a minimum unit of power generation, an air supply channel 4 that supplies air to the fuel cell 3, and an air exhaust channel 5 that discharges the air to the outside. A fuel supply channel 6 for supplying fuel gas to the fuel cell 3, a fuel exhaust channel 7 for discharging the fuel gas to the outside, and a plurality of sets of the fuel cells 3 are stacked to form a cell group. Is fixed to a fuel cell stack 8, a container 10 for storing the fuel cell stack 8, and an output member 11 for outputting electricity generated by the fuel cell stack 8.

[Fuel battery cell]
The fuel cell 3 has a square shape in plan view, and as shown in FIG. 3, it is formed of a ferritic stainless steel having conductivity in the form of a square plate (* "up" or "down" here is a drawing) However, this is merely for convenience of explanation and does not mean absolute top and bottom. The same shall apply hereinafter.), A ferritic stainless steel having conductivity in the form of a square plate, etc. An electrode (hereinafter referred to as an “air electrode”) is formed on the surface of the lower interconnector 13 formed in the above and the upper and lower interconnectors 12, 13 and substantially opposite the inner surface (lower surface) of the interconnector 12 on the electrolyte 2. ) 14 and the other electrode (hereinafter referred to as “fuel electrode”) 15 is formed on the surface facing the inner surface (upper surface) of the lower interconnector 13. A body 20, an air chamber 16 formed between the upper interconnector 12 and the air electrode 14, a fuel chamber 17 formed between the lower interconnector 13 and the fuel electrode 15, and the air chamber 16. A current collecting member 180 on the air electrode 14 side that is disposed inside and electrically connects the air electrode 14 and the upper interconnector 12, a fuel electrode 15 disposed inside the fuel chamber 17, and the lower interconnector 13 A current collecting member 190 on the fuel electrode 15 side that electrically connects to each other, and through-holes through corner through holes 47, 47... Passing through tightening members 46a to 46d (to be described later) of the fixing member 9 through a square corner portion. Is formed.

[Electrolytes]
The electrolyte 2 is made of LaGaO ₃ ceramic, BaCeO ₃ ceramic, SrCeO ₃ ceramic, SrZrO ₃ ceramic, CaZrO ₃ ceramic, etc. in addition to ZrO ₂ ceramic.

[Fuel electrode]
The material of the fuel electrode 15 is made of a metal such as Ni and Fe and a ceramic such as ZrO ₂ ceramic such as zirconia stabilized by at least one kind of rare earth elements such as Sc and Y, and CeO ₂ ceramic. A mixture with at least one of them is mentioned. The material of the fuel electrode 15 may be a metal such as Pt, Au, Ag, Pb, Ir, Ru, Rh, Ni and Fe. These metals may be only one kind, or two or more kinds of alloys. Also good. Furthermore, a mixture (including cermet) of these metals and / or alloys and at least one of each of the above ceramics may be mentioned. Moreover, the mixture etc. of metal oxides, such as Ni and Fe, and at least 1 type of each of the said ceramic are mentioned.

[Air electrode]
As the material of the air electrode 14, for example, various metals, metal oxides, metal double oxides, and the like can be used. Examples of the metal include metals such as Pt, Au, Ag, Pb, Ir, Ru, and Rh, or alloys containing two or more metals. Further, examples of the metal oxide include oxides such as La, Sr, Ce, Co, Mn and Fe (La ₂ O ₃ , SrO, Ce ₂ O ₃ , Co ₂ O ₃ , MnO ₂ and FeO). It is done. As the double oxide, a double oxide containing at least La, Pr, Sm, Sr, Ba, Co, Fe, Mn, etc. (La _1-X Sr _X CoO ₃ -based double oxide, La _1-X Sr _X FeO ₃ -based double oxide, La _1-X Sr _X Co _1-y FeO ₃ -based double oxide, La _1-X Sr _X MnO ₃ -based double oxide, Pr _1-X Ba _X CoO ₃ -based double oxide And Sm _1-X Sr _X CoO ₃ -based double oxide).

[Fuel chamber]
As shown in FIGS. 3 to 5, the fuel chamber 17 surrounds the current collecting member 190 and is installed on the upper surface of the lower interconnector 13 to form a fuel electrode gas flow path forming insulator in a frame shape. The frame (hereinafter also referred to as “fuel electrode insulating frame”) 21 and a fuel electrode frame 22 which is in the form of a frame and installed on the upper surface of the fuel electrode insulating frame 21 are formed in a square room shape.

[Current collector on the fuel chamber side]
The current collecting member 190 on the fuel chamber 17 side is formed of, for example, Ni that has been annealed (HV hardness is 200 or less) by heat treatment at 1000 ° C. for one hour in a vacuum, and contacts the lower interconnector 13. A series of a connector contact portion 190a, a cell body contact portion 190b that contacts the fuel electrode 15 of the cell body 20, and a U-shaped connecting portion 190c that connects the connector contact portion 190a and the cell body contact portion 190b. Is formed. The current collecting member 190 of the embodiment is formed of a foil material having a thickness of about 30 μm. Therefore, the connecting portion 190c can be bent and stretched in the direction intersecting the surface and hardly generates a repulsive force against bending and stretching.

  The current collecting member 190 on the fuel chamber 17 side may be formed of, for example, a porous metal made of Ni, a metal mesh, a wire, or a punching metal in addition to the case of forming the foil material as described above. Further, the current collecting member 190 on the fuel chamber 17 side may be formed of a metal resistant to oxidation such as Ni alloy or stainless steel in addition to Ni.

  The current collecting member 190 is provided in the fuel chamber 17 with several tens to hundreds (of course, depending on the size of the fuel chamber), and these are individually arranged on the interconnector 13 and welded (for example, laser welding or resistance). However, preferably, the foil material is processed into a square flat plate 190p aligned with the fuel chamber 17 as shown in FIG. 10B, and the cell main body abutting portion 190b is connected to the flat plate 190p. A cut line 190d corresponding to the connecting portion 190c is formed, and the connecting portion 190c is bent into a U shape as shown in the enlarged portion of FIG. An interval t (see the enlarged portion in FIG. 5) is provided above the cover. Therefore, the perforated flat plate 190p left by bending and raising the cell main body contact portion 190b is an assembly of the connector contact portions 190a. In the embodiment, the connector contact portion 190a of the flat plate 190p is attached to the lower interconnector 13. Joined by laser welding or resistance welding.

  The cut line 190d of the current collecting member 190 may have a shape in which the cell main body abutting portion 190b and the connecting portion 190c are grouped as shown in FIG. By doing so, the cell main body contact portion 190b and the connecting portion 190c can be processed efficiently.

[spacer]
The current collecting member 190 is provided with a spacer 580 as shown in FIG. The spacer 580 is disposed in the fuel chamber 17 between the cell body 20 and the lower interconnector 13 so as to separate the connector abutting portion 190a and the cell body abutting portion 190b, and in the thickness direction. The cell body contact portion 190b and the connector contact portion 190a are brought into contact with each other, that is, the cell body contact portion by thermal expansion in the thickness direction of the spacer 580 at least in the fuel cell operating temperature range. In order to be able to press 190b toward the cell main body 20 and the connector abutting portion 190a toward the interconnector 13, it expands by thermal expansion in the fuel cell operating temperature range of 700 ° C to 1000 ° C. It is formed of a thickness and material that exceeds the distance t by further thermal expansion.

  The spacer 580 may have a thickness that exceeds the distance t (see FIG. 5) between the cell main body contact portion 190b and the connector contact portion 190a in the fuel cell operating temperature range. It is preferable to set the distance between the cell main body contact portion 190b and the connector contact portion 190a to be approximately the same or slightly larger at room temperature when the battery is not operated. By doing so, the electrical contact between the connector contact portion 190a and the interconnector 13 and the cell body contact portion 190b and the cell body 20 is stabilized by the spacer 580 even during the period from the start of power generation to the operating temperature range. be able to.

  In addition, the spacer 580 is made of a material having an elastic amount larger than that of the current collecting member 190 in the thickness direction, and is relatively resistant to fluctuations in the interval between the fuel chambers 17 due to changes in temperature cycle, fuel pressure, and air pressure. The thickness is greatly increased or decreased as compared with the current collecting member 190 having a small elastic amount. Specifically, the fuel chamber 17 contracts in the thickness direction with respect to the reduction in the interval to exert a buffering action, thereby preventing the cell main body 20 from cracking, and conversely, with respect to the increase in the interval, the thickness increases. The electrical contact is stabilized by the restoring force in the vertical direction.

Here, a specific method for comparing the elastic amount of the spacer 580 and the current collecting member 190 can be performed by measuring the elastic amount by the following compression test.
First, a sample for a compression test is prepared for each of the spacer 580 and the current collecting member 190. The size was 6.5 mm × 4 mm in accordance with the contact area between the actual spacer 580 and the current collecting member, and the thickness was 0.4 mm and the current collecting member thickness was 30 μm. Here, the thickness of the spacer 580 and the current collecting member 190 is desirably matched to the shape at the time of use, and the size may be any size as long as both are the same.
Next, the sample is compressed with 10 kg with a compression tester, and the displacement (mm) of the thickness at that time is measured to obtain the maximum displacement.
Further, the compression of 10 kg is released, and the restoration displacement amount (see the graph of FIG. 12) from the maximum displacement amount is measured.
In addition, the current collecting member 190 having a thickness of 30 μm has a small amount of displacement and may not be measured depending on the accuracy of the compression tester. In that case, the compression test is performed by stacking several (for example, 10) thin current collecting members 190, and the obtained displacement is divided by the number of the stacked sheets to obtain the maximum displacement and the restored displacement. It can be measured.
In the case of a sample having a shape at the time of use, a larger restoration displacement means that the elasticity is larger, and conversely, a smaller restoration displacement means that the elasticity is smaller.
When the above test is performed on the spacer 580 and the current collecting member 190 of the present invention, the spacer 580 exhibits an overwhelmingly large displacement with respect to the current collecting member 190 as shown in the graph of FIG.

  The spacer 580 is formed of a material that does not sinter with the current collecting member 190 in the fuel cell operating temperature range. Therefore, the cell main body contact portion 190b and the connector contact portion 190a are in direct contact with each other. Of course, there is no risk of sintering, and there is no risk of the cell body contact portion 190b and the connector contact portion 190a being sintered via the spacer 580.

  As a material of the spacer 580 satisfying the above conditions, any one of mica, alumina felt, vermiculite, carbon fiber, silicon carbide fiber, and silica, or a combination of a plurality of types may be used. Moreover, if these are made into the laminated structure of a thin plate-like body like mica, moderate elasticity with respect to the load to a lamination direction is provided. The spacers 580 formed of these materials have a thermal expansion coefficient in the thickness direction (stacking direction) higher than the thermal expansion coefficient in the axial direction of fastening members 46a to 46d described later.

In addition, the current collecting member 190 of the embodiment has an integral structure connected by the flat plate 190p that is an assembly of the connector contact portions 190a as described above, and the spacer 580 is also shown in FIG. As shown in the figure, one piece of rectangular material that is substantially the same width as the flat plate 190p and slightly shorter than the flat plate 190p (specifically, a length corresponding to the length of one (cell main body contact portion 190b + connecting portion 190c)). The portions corresponding to the cell main body abutting portion 190b and the connecting portion 190c are cut out from the sheet by one horizontal row and formed in a horizontal lattice shape.
Then, this spacer 580 is overlaid on the flat plate 190p shown in FIG. 10B before processing the current collecting member 190, and in this state, the connecting portion 190c is bent into a U shape as shown in the enlarged portion of FIG. By doing so, the current collecting member 190 in which the spacer 580 is incorporated in advance is obtained.
By the way, in the enlarged portion of FIG. 9, the cell main body contact portion 190b is bent in a stepwise manner from the one located at the left corner portion, but this is drawn only to explain the processing procedure. Therefore, the bending of the cell main body contact portion 190b may be performed all at once, or may be sequentially performed from a portion convenient for processing.

[Air chamber]
As shown in FIGS. 3 to 5, the air chamber 16 has a rectangular frame shape and has a conductive thin metal separator 23 with the electrolyte 2 attached to the lower surface thereof, and the separator 23 and the upper side. A frame-shaped insulating frame for forming an air electrode gas flow channel (hereinafter also referred to as “air electrode insulating frame”) 24 that is installed between the interconnector 12 and surrounds the current collecting member 180. It is formed in a shape.

[Current collector on the air chamber side]
The current collecting member 180 on the air chamber 16 side has a long and narrow rectangular shape and is formed of a dense conductive member such as stainless steel, and contacts the air electrode 14 on the upper surface of the electrolyte 2 and the lower surface (inner surface) of the upper interconnector 12. Plural pieces are arranged in parallel and at a constant interval in contact with each other. The current collecting member 180 on the air chamber 16 side may have the same structure as that of the current collecting member 190 on the fuel chamber 17 side (including a second embodiment described later).

  As described above, the fuel cell 3 includes a combination of the lower interconnector 13, the fuel electrode insulating frame 21, the fuel electrode frame 22, the separator 23, the air electrode insulating frame 24, and the upper interconnector 12. To form the fuel chamber 17 and the air chamber 16, partition the fuel chamber 17 and the air chamber 16 with the electrolyte 2 to make them independent from each other, and further, connect the fuel electrode insulating frame 21 and the air electrode insulating frame 24 to the fuel electrode 15 side. The air electrode 14 side is electrically insulated.

  The fuel cell 3 also includes an air supply unit 25 including an air supply channel 4 that supplies air into the air chamber 16, and an air exhaust including an air exhaust channel 5 that discharges air from the air chamber 16 to the outside. A fuel supply unit 27 including a fuel supply channel 6 for supplying fuel gas to the inside of the fuel chamber 17 and a fuel exhaust unit 28 including a fuel exhaust channel 7 for discharging the fuel gas from the fuel chamber 17 to the outside. And.

[Air supply section]
The air supply unit 25 has an air supply through hole 29 opened in the vertical direction at the center of one side of the square fuel cell 3 and a long hole formed in the air electrode insulating frame 24 so as to communicate with the air supply through hole 29. The air supply communication chamber 30, the air supply communication portion 32 formed by recessing a plurality of upper surfaces of the partition wall 31 partitioning the air supply communication chamber 30 and the air chamber 16 at equal intervals, and the air supply through hole 29. And the air supply flow path 4 for supplying air to the air supply communication chamber 30 from the outside.

[Air exhaust part]
The air exhaust unit 26 includes an air exhaust passage 33 opened in the vertical direction at the center of one side opposite to the air supply unit 25 of the fuel cell 3, and an air electrode insulating frame so as to communicate with the air exhaust passage 33. 24, an air exhaust communication chamber 34 having a long hole shape, and an air exhaust communication portion 36 formed by recessing a plurality of upper surfaces of partition walls 35 partitioning the air exhaust communication chamber 34 and the air chamber 16 at equal intervals. And the tubular air exhaust passage 5 which is inserted into the air exhaust hole 33 and exhausts air from the air exhaust communication chamber 34 to the outside.

[Fuel supply section]
The fuel supply unit 27 includes a fuel supply through hole 37 opened in the vertical direction at the center of one side of the remaining two sides of the square fuel cell 3, and the fuel electrode insulating frame 21 so as to communicate with the fuel supply through hole 37. A fuel supply communication chamber 40 formed in the shape of a long hole, and a plurality of upper surfaces of partition walls 39 partitioning between the fuel supply communication chamber 38 and the fuel chamber 17 are formed at equal intervals. And a tubular fuel supply passage 6 which is inserted into the fuel supply passage 37 and supplies fuel gas to the fuel supply communication chamber 38 from the outside.

[Fuel exhaust part]
The fuel exhaust unit 28 includes a fuel exhaust passage 41 opened in the vertical direction at the center of one side opposite to the fuel supply unit 27 of the fuel cell 3, and a fuel electrode insulating frame so as to communicate with the fuel exhaust passage 41. And a fuel exhaust communication portion 44 formed by recessing a plurality of upper surfaces of partition walls 43 partitioning between the fuel exhaust communication chamber 42 and the fuel chamber 17 at equal intervals. A tubular fuel exhaust passage 7 that is inserted into the fuel exhaust passage 41 and discharges fuel gas from the fuel exhaust communication chamber 42 to the outside.

[Fuel cell stack]
The fuel cell stack 8 is configured by stacking a plurality of sets of the fuel cells 3 to form a cell group, and fixing the cell group with a fixing member 9. When a plurality of sets of fuel cells 3 are stacked, the interconnector 12 above the fuel cell 3 positioned below and the interconnector 13 below the fuel cell 3 placed thereon are integrated with each other. One sheet is shared between the upper and lower fuel cells 3 and 3.
The fixing member 9 includes a pair of end plates 45a and 45b sandwiching the upper and lower sides of the cell group, the end plates 45a and 45b and the cell group at a corner hole (not shown) of the end plate 45a and 45b, and the corner of the cell group. Four sets of fastening members 46a to 46d that are tightened with nuts through bolts through the through holes 47 are combined. The material of the fastening members 46a to 46d is, for example, Inconel 601.

  The air supply flow path 4 is attached to the fuel cell stack 8 so as to penetrate the through holes (not shown) of the end plates 45a and 45b and the air supply through holes 29 of the cell group vertically, Air is supplied to the air supply communication chamber 30 through the horizontal hole 48 by closing the end of the tubular flow path and providing the horizontal hole 48 as shown in FIG. It has come to be.

  Similarly, the air exhaust passage 5 takes in air from a lateral hole 49 corresponding to each air exhaust communication chamber 34 and discharges it to the outside, and the fuel supply passage 6 is provided for each fuel supply communication chamber 38 as shown in FIG. The fuel gas is supplied from the lateral hole 50 corresponding to the fuel exhaust, and the fuel exhaust passage 7 takes in the fuel gas from the lateral hole 51 corresponding to each fuel exhaust communication chamber 42 and discharges it outside.

[container]
The container 10 for storing the fuel cell stack 8 has a heat-resistant and sealed structure, and as shown in FIG. 1, two halves 53a and 53b having flanges 52a and 52b at the openings are joined to each other. It is a thing. The bolts of the fastening members 46 a to 46 d protrude from the top of the container 10, and a nut 54 is screwed into the protruding part of the fastening members 46 a to 46 d to fix the fuel cell stack 8 in the container 10. Further, the air supply flow path 4, the air exhaust flow path 5, the fuel supply flow path 6 and the fuel exhaust flow path 7 also protrude outside from the top of the container 10, and a supply source of air or fuel gas, etc. Is connected.

[Output member]
The output member 11 that outputs the electricity generated by the fuel cell stack 8 is the fastening members 46a to 46d and the end plates 45a and 45b located at the corners of the fuel cell stack 8, and a pair of fastening members facing each other diagonally. The members 46a and 46c are electrically connected to the upper end plate 45a which is a positive electrode, and the other pair of fastening members 46b and 46d are electrically connected to the lower end plate 45b which is a negative electrode. Of course, the fastening members 46a and 46d connected to the positive electrode and the fastening members 46b and 46c connected to the negative electrode interpose the insulating washer 55 (see FIG. 1) with respect to the end plate 45a (45b) of the other electrode, and the fuel. The battery stack 8 is insulated by providing a gap between the corner through hole 47 and the like. Therefore, the fastening members 46a and 46c of the fixing member 9 also function as positive output terminals connected to the upper end plate 45a, and the other fastening members 46b and 46d are negative electrodes connected to the lower end plate 45b. Also functions as an output terminal.

[Power generation]
When air is supplied to the air supply channel 4 of the fuel cell 1, the air flows from the right side to the left side in FIG. 7, and the right air supply channel 4, the air supply communication chamber 30, and the air supply communication unit 32. Is supplied to the air chamber 16 through the air supply unit 25, passes through the gas flow path 56 between the current collecting members 180 of the air chamber 16, and further, the air exhaust communication unit 36 and the air exhaust communication chamber 34. Then, the air is discharged to the outside through the air exhaust portion 26 including the air exhaust passage 5.

At the same time, when hydrogen, for example, is supplied as a fuel gas to the fuel supply channel 6 of the fuel cell 1, the fuel gas flows from the upper side to the lower side in FIG. 8, and the upper fuel supply channel 6, the fuel supply communication chamber 38, Are supplied to the fuel chamber 17 through the fuel supply unit 27 including the fuel supply communication unit 40, and strictly between the current collecting members 190, 190 ... of the fuel chamber 17, the cell main body contact portions 190b, 190b ... The gas passage 57 between them (see the non-hatched portion in the fuel chamber 17 in FIG. 8) passes through while diffusing, and further, the fuel exhaust communication section 44, the fuel exhaust communication chamber 42, and the fuel exhaust flow path 7 It is exhausted to the outside through the fuel exhaust part 28 comprising
At this time, if the current collecting member 190 is formed of a porous metal, a metal mesh, a wire, or a punching metal as described above, the surface of the gas flow channel 57 becomes uneven, so that the diffusibility of the fuel gas is improved.

  When the temperature in the container 10 is raised to 700 ° C. to 1000 ° C. while supplying and exhausting such air and fuel gas, the air and fuel gas are passed through the air electrode 14, the electrolyte 2, and the fuel electrode 15. In order to cause a reaction, DC electric energy is generated with the air electrode 14 as a positive electrode and the fuel electrode 15 as a negative electrode. In addition, since the principle which an electrical energy generate | occur | produces in the fuel cell 3 is known, description is abbreviate | omitted.

  As described above, the air electrode 14 is electrically connected to the upper interconnector 12 via the current collecting member 180, while the fuel electrode 15 is electrically connected to the lower interconnector 13 via the current collecting member 190. In addition, since the fuel cell stack 8 is in a state where a plurality of fuel cells 3 are stacked and connected in series, the upper end plate 45a is a positive electrode and the lower end plate 45b is a negative electrode. Thus, the electrical energy can be taken out through the fastening members 46a to 46d that also function as output terminals.

As described above, the fuel cell repeats a temperature cycle in which the temperature rises during power generation and the temperature drops due to power generation stop. Therefore, thermal expansion and contraction are repeated for all members constituting the fuel chamber 17 and the air chamber 16 and the fastening members 46a to 46d, and accordingly, the intervals between the fuel chamber 17 and the air chamber 16 are repeatedly expanded and contracted.
Further, the fuel pressure and air pressure may also fluctuate, and the space between the fuel chamber 17 and the air chamber 16 is expanded or reduced by the deformation of the cell body 20 due to the fluctuation of the pressure.
In response to such a change in the expansion direction of the fuel chamber 17 and the air chamber 16, in the embodiment, the current collecting member 190 on the fuel chamber 17 side is exclusively used in the stacking direction of the spacers 580 (= thickness direction or tightening members 46a to 46a). The electrical contact is stably maintained because the cell body 20 is pressed by the thermal expansion in the same direction as the elastic force in the tightening direction (46d). Since the pressing of the cell body 20 by the current collecting member 190 also affects the air chamber 16 side, the electrical contacts of the air chamber 16 are also stably maintained.
Further, the stress applied to the cell body 20 is alleviated by contraction of the spacer 580 exclusively on the fuel chamber 17 side with respect to changes in the shrinking direction of the fuel chamber 17 and the air chamber 16.

Further, when the current collecting member 190 on the fuel electrode 15 side is Ni or Ni alloy, the cell main body contact portion 190b is diffused and joined with Ni in the fuel electrode 15 in a high temperature environment during power generation. Therefore, the electrical connection by the current collecting member 190 is more stably maintained.
It is preferable to apply a NiO paste to the fuel electrode 15 to form a bonding layer. By doing so, NiO is changed to Ni by energization in H ₂ , so that the joining property of the current collecting member 190 and the fuel electrode 15 is further improved. The bonding layer may be formed by applying a Pt paste to the fuel electrode 15.

  In the first embodiment, the lower interconnector 13 is joined by welding the flat plate 190p, which is an assembly of the connector contact portions 190a, but the interconnector 13 and the flat plate 190p are made of a high temperature environment during power generation. If a combination that allows diffusion bonding underneath (for example, Crofer 22H and Ni) or a bonding layer as described above is formed on the inner surface side of the lower interconnector 13, it is possible to operate in a high temperature environment during power generation. The interconnector 13 and the current collecting member 190 can be joined together.

[Embodiment 2]
13 to 16 are longitudinally omitted sectional views of the fuel cell 3 showing the second embodiment. In the first embodiment, the connecting portion 190c of the current collecting member 190 is bent in a U shape so that the cell body contact portion 190b is disposed above the connector contact portion 190a, and the connector contact portion 190a and the cell body contact portion 190b are arranged. In the second embodiment, the connecting portion 190c is inclined and the vertical positions of the connector abutting portion 190a and the cell main body abutting portion 190b are completely different as shown in FIG. Alternatively, as shown in FIG. 14, the current collecting member 190 has a substantially Z-shaped cross section and is arranged so that the connector abutting portion 190a and a part of the cell main body abutting portion 190b overlap each other at different vertical positions. The spacer 580 is disposed so as to separate the contact portion 190a from the cell body 20 and the cell body contact portion 190b from the interconnector 13. Further, as shown in FIG. 15, a spacer 580 is interposed so as to separate the connector abutting portion 190a from the cell body 20, or as shown in FIG. 16, the spacer 580 is separated from the cell body abutting portion 190b and the interconnector 13. It can also be made to intervene.
The difference between the configurations of the first embodiment and the second embodiment is as described above, and the other points are the same as those of the first embodiment, and thus detailed description thereof is omitted.

DESCRIPTION OF SYMBOLS 1 ... Fuel cell 2 ... Electrolyte 3 ... Fuel cell 8 ... Fuel cell stack 12, 13 ... Interconnector 14 ... Air electrode 15 ... Fuel electrode 180, 190 ... Current collection member 190a ... Connector contact part 190b ... Cell main body contact Part 190c ... Connection part 20 ... Cell body 46a to 46d ... Tightening member 580 ... Spacer

Claims (12)

A pair of interconnectors;
A cell body having electrodes formed on the upper and lower surfaces of the plate-like electrolyte, spaced apart from each of the interconnectors,
A fuel cell comprising: a current collecting member disposed between at least one of the electrodes and the interconnector, and electrically connecting the electrode and the interconnector,
The current collecting member includes a connector abutting portion that abuts on the interconnector, a cell body abutting portion that abuts on the electrode of the cell body, and a connecting portion that connects the connector abutting portion and the cell body abutting portion. And are formed in a series,
Having a spacer disposed between the connector contact portion and the cell body contact portion;
The current collecting member and the spacer have elasticity in a direction in which the distance between the cell main body and the interconnector increases, and the elastic amount of the spacer is larger than the elastic amount of the current collecting member. cell. The connection portion is bent Ri folded, the connector fuel cell according to claim 1, wherein the cell body abutment portion and the contact portion are disposed on both sides of the spacer. A pair of interconnectors;
A cell body having electrodes formed on the upper and lower surfaces of the plate-like electrolyte, spaced apart from each of the interconnectors,
A fuel cell comprising: a current collecting member disposed between at least one of the electrodes and the interconnector, and electrically connecting the electrode and the interconnector,
The current collecting member includes a connector abutting portion that abuts on the interconnector, a cell body abutting portion that abuts on the electrode of the cell body, and a connecting portion that connects the connector abutting portion and the cell body abutting portion. And are formed in a series,
A spacer disposed between the connector contact portion and the cell body, and between the cell body contact portion and the interconnector;
The current collecting member and the spacer have elasticity in a direction in which the distance between the cell main body and the interconnector increases, and the elastic amount of the spacer is larger than the elastic amount of the current collecting member. cell. A pair of interconnectors;
A cell body having electrodes formed on the upper and lower surfaces of the plate-like electrolyte, spaced apart from each of the interconnectors,
A fuel cell comprising: a current collecting member disposed between at least one of the electrodes and the interconnector, and electrically connecting the electrode and the interconnector,
The current collecting member includes a connector abutting portion that abuts on the interconnector, a cell body abutting portion that abuts on the electrode of the cell body, and a connecting portion that connects the connector abutting portion and the cell body abutting portion. And are formed in a series,
Between the connector contact portion and the cell body, or between the cell body contact portion and the interconnector, has a spacer disposed,
The current collecting member and the spacer have elasticity in a direction in which the distance between the cell main body and the interconnector increases, and the elastic amount of the spacer is larger than the elastic amount of the current collecting member. cell.   The fuel cell according to any one of claims 1 to 4, wherein the spacer is at least one of mica, alumina felt, vermiculite, carbon fiber, silicon carbide fiber, and silica. The interconnector, the cell body, and the current collecting member are further stacked and tightened together to further tighten,
The clamping member and the spacer are pressed so that the cell main body contact portion of the current collecting member contacts the cell main body and / or the connector contact portion contacts the interconnector. The fuel battery cell according to any one of claims 1 to 5.   The fuel cell according to claim 6, wherein the spacer has a higher coefficient of thermal expansion in the tightening direction than the tightening member.   The fuel cell according to any one of claims 1 to 7, wherein the current collecting member is made of a porous metal, a metal mesh, a wire, or a punching metal.   The fuel cell according to any one of claims 1 to 8, wherein the cell main body contact portion of the current collecting member is bonded to a surface of the at least one electrode of the cell main body. .   The fuel cell according to any one of claims 1 to 9, wherein the connector contact portion of the current collecting member is joined to the interconnector. The fuel cell according to any one of claims 1 to 10 , wherein the current collecting member is disposed between a fuel electrode and the interconnector and is made of Ni or a Ni alloy. Fuel cell stack, characterized by comprising fixed by Tightening member by stacking a plurality of fuel cell according to any one of claims 1 to 1 1.

Images