JPWO2017208904A1 - Fuel cell stack - Google Patents

Abstract

  In a fuel cell stack in which spacers are arranged between fuel cells, a fuel cell stack capable of suppressing the occurrence of a leak at a spacer connecting portion is provided. A fuel cell stack according to one aspect of the present invention includes a plurality of solid oxide fuel cells, a spacer provided between one fuel cell and another fuel cell, and formed of ceramics. An adhesive layer that bonds the one fuel cell and the spacer, and a plurality of spacers are stacked, and the spacer disposed on the one fuel cell side of the one fuel cell at the time of power generation It is comprised so that it may deform | transform with a deformation | transformation.

Description

  The present invention relates to a fuel cell stack.

  Conventionally, various solid oxide fuel cells using a solid oxide electrolyte have been proposed. In a solid oxide fuel cell, a plurality of fuel cells are stacked in order to obtain a sufficient voltage. Thereby, a fuel cell stack is configured. When fuel cells are formed using ceramics, the thermal conductivity of ceramics is low. Therefore, if the number of stacked fuel cells using ceramics is increased, the heat generated by power generation near the center of the fuel cell stack. Tend to stay. Therefore, heat distribution occurs on the surface of the fuel cell, and cracks occur in the fuel cell due to thermal stress.

  In order to avoid such a problem, Patent Document 1 discloses a fuel cell stack in which a joint including a metal plate is provided between fuel cells. In Patent Document 1, the metal plate is divided into a plurality of parts in the plane direction, and a spacer made of ceramics is arranged in a region where the metal plate is not arranged.

International Publication No. 2015/045986

  During power generation, the fuel cell may be deformed due to factors such as the difference in thermal expansion coefficient of the cell constituent material, the temperature distribution in the stack, and vibration. At this time, gas leakage occurs in the region where the spacer is arranged in the fuel cell, and in the worst case, it leads to generation of a crack.

  There are various problems due to the occurrence of cracks, such as an increase in internal resistance due to the rupture of electrically conductive vias in the cell, a decrease in the effective electrode area due to the destruction of the electrode part, and a gas leak if a crack occurs in the flow path part. The fuel utilization rate and air utilization rate are reduced due to the occurrence. In particular, the characteristic deterioration due to fuel leakage is large, and the suppression of leakage is an important issue.

  The present invention has been made in view of such circumstances, and provides a fuel cell stack in which a spacer connection portion can be prevented from leaking in a fuel cell stack in which spacers are arranged between fuel cells. For the purpose.

  A fuel cell stack according to one aspect of the present invention includes a plurality of solid oxide fuel cells, a spacer provided between one fuel cell and another fuel cell, and formed of ceramics. An adhesive layer that bonds the one fuel cell and the spacer, and a plurality of spacers are stacked, and the spacer disposed on the one fuel cell side of the one fuel cell at the time of power generation It is comprised so that it may deform | transform with a deformation | transformation.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress that a leak arises in one fuel battery cell in the fuel battery stack which has arrange | positioned the spacer between fuel battery cells.

1 is a schematic front sectional view showing a main part of a fuel cell stack according to an embodiment. It is a disassembled perspective view of one fuel battery cell used for the fuel cell stack of this embodiment. It is a top view of one fuel cell used for the fuel cell stack concerning this embodiment. It is a perspective view showing typically a part of fuel cell stack of this embodiment. It is a top view which shows arrangement | positioning of the spacer used for the fuel cell stack which concerns on this embodiment. It is a schematic sectional drawing which shows the structure of the spacer in the fuel cell stack which concerns on 1st Embodiment. It is a schematic sectional drawing which shows the structure of the spacer in the fuel cell stack of a comparative example. It is a schematic sectional drawing which shows the structure of the spacer in the fuel cell stack which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows the structure of the spacer in the fuel cell stack which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows the structure of the spacer in the fuel cell stack which concerns on 4th Embodiment. It is a schematic sectional drawing which shows the structure of the spacer in the fuel cell stack which concerns on 5th Embodiment. It is a schematic sectional drawing which shows the structure of the spacer in the fuel cell stack which concerns on 6th Embodiment. It is a schematic sectional drawing which shows the structure of the spacer in the fuel cell stack concerning 7th Embodiment. It is a schematic sectional drawing which shows the modification of the structure of the spacer in the fuel cell stack concerning 7th Embodiment.

(First embodiment)
FIG. 1 is a schematic front sectional view of a fuel cell stack according to a first embodiment of the present invention. In the fuel cell stack 1, the upper fuel cell 2 and the lower fuel cell 2 are joined via a joint 4. In FIG. 1, two fuel battery cells 2 and 2 are shown, but in this embodiment, a structure in which the fuel battery cells 2 and 2 on both sides are stacked via the joint 4 is further connected.

  Moreover, in FIG. 1, only the position in which the fuel battery cells 2 and 2 are provided is schematically illustrated. Details of one fuel cell 2 will be described with reference to FIGS. 2 and 3.

  As shown in FIG. 2, the fuel battery cell 2 has a solid oxide electrolyte layer 7. The solid oxide electrolyte layer 7 is made of a ceramic having high ionic conductivity. Examples of such materials include stabilized zirconia and partially stabilized zirconia. More specifically, zirconia stabilized by yttrium or scandium can be mentioned. Examples of the stabilized zirconia include 10 mol% yttria stabilized zirconia (10YSZ) and 11 mol% scandia stabilized zirconia (11ScSZ). Examples of the partially stabilized zirconia include 3 mol% yttria partially stabilized zirconia (3YSZ).

Incidentally, the material constituting the solid oxide electrolyte layer 7 is not limited to the above, Sm and Gd-doped ceria-based oxide _{and, La 0.8 Sr 0.2 Ga 0.8 Mn} 0.2 O You may form by perovskite type oxides, such as _(3-delta) . Δ represents a positive number less than 3.

  The solid oxide electrolyte layer 7 is provided with a through hole 7a and a through hole 7b. The through hole 7a constitutes a fuel gas flow path. The through hole 7b constitutes an air flow path through which air as an oxidant gas passes.

  A fuel electrode layer 6 is laminated above the solid oxide electrolyte layer 7. The fuel electrode layer 6 can be composed of yttria-stabilized zirconia containing Ni, scandia-stabilized zirconia containing Ni, or the like. The fuel electrode layer 6 is provided with a slit 6a constituting a fuel gas flow path and a slit 6b constituting an air flow path.

  A separator 5 is laminated on the fuel electrode layer 6. The separator 5 can be formed of magnesia spinel, alumina, zircon, stabilized zirconia, partially stabilized zirconia, or the like. Through holes 5 a and 5 b are formed in the separator 5. The through hole 5a constitutes a fuel gas flow path. The through hole 5b constitutes an air flow path.

  In the separator 5, a plurality of interconnectors 5 c for taking out electricity are provided so as to penetrate the lower surface from the upper surface of the separator 5. That is, each interconnector 5c is formed by a via-hole conductor. The plurality of interconnectors 5 c are electrically connected to the fuel electrode layer 6.

An air electrode layer 8 and a separator 9 are stacked below the solid oxide electrolyte layer 7. The air electrode layer 8 is provided with a slit 8a that constitutes a fuel gas passage and a slit 8b that constitutes an air passage. The air electrode layer 8 is preferably made of a porous material having high electron conductivity. Such an air electrode layer 8 includes, for example, scandia-stabilized zirconia (ScSZ), ceria doped with Gd, indium oxide doped with Sn, PrCoO ₃ oxide, LaCoO ₃ oxide, or LaMnO ₃ oxide. It can be formed of an oxide or the like. Examples of the LaMnO ₃ oxide include La _0.8 Sr _0.2 MnO ₃ (hereinafter abbreviated as LSM) and La _0.6 Ca _0.4 MnO ₃ (hereinafter abbreviated as LCM). .

  The separator 9 is configured similarly to the separator 5. Therefore, it has the through-hole 9a which comprises a fuel gas flow path, the through-hole 9b which comprises an air flow path, and the several interconnector 9c.

  FIG. 3 shows a plan view of the single fuel cell 2. As shown in FIG. 3, the fuel battery cell 2 has a cross-shaped flow path component 2a and four power generation units 2b, 2c, 2d, and 2e partitioned by the flow path component 2a when viewed in plan. . And the said interconnector 5c is exposed to the upper surface of the electric power generation parts 2b-2e.

  Returning to FIG. 1, in the fuel cell stack 1 of the present embodiment, a plurality of such fuel cells 2 are stacked. FIG. 4 is a perspective view showing a part of the fuel cell stack 1. The part corresponds to a portion where one power generation section 2b, 2c, 2d or 2e divided by the cross-shaped flow path constituting section 2a shown in FIG. 3 is laminated. As shown in FIG. 4, the fuel cells 2 are stacked via the joints 4. Actually, as shown in FIG. 1, the power generation units 2b and 2c are located on both sides of the flow path component 2a.

  The fuel cell 2 described above has an advantage that the fuel cell 2 can be formed by co-sintering all at once by using ceramics as an element constituting the fuel cell. By not using metal in the fuel cell 2, there is an advantage that the source of chromium poisoning the cathode (air electrode layer 8) can be eliminated, and the metal / ceramic seal portion can be eliminated. On the other hand, since the thermal conductivity of the separator 5 is low, heat generated by power generation is not dissipated and thermal stress is easily applied. For this reason, as shown in FIG. 4, the junction part 4 containing a metal plate (soaking plate) is provided every several steps of the fuel battery cell 2, and the in-plane temperature distribution generated by heat generation is made uniform.

  Returning to FIG. 1, the feature of the fuel cell stack 1 of the present embodiment is the configuration of the joint 4 that joins the fuel cell 2 and the fuel cell 2.

  The joint 4 physically joins and integrates the upper fuel cell 2 and the lower fuel cell 2 and electrically connects the upper fuel cell 2 and the lower fuel cell 2 in series. Connected.

  In FIG. 1, in the fuel cell 2, the portion indicated by the broken lines A and B corresponds to the flow path component 2 a. The power generation units 2b and 2c are located on both sides of the flow path component 2a. A metal plate 11 is provided in order not to concentrate heat in the center and to electrically connect the upper fuel cell 2 and the lower fuel cell 2.

  Although it does not specifically limit as a material which comprises the metal plate 11, It is desirable to use the metal with a thermal expansion coefficient close | similar to the ceramic which comprises the fuel cell 2. FIG. Such a material is preferably ferritic stainless steel. The thermal expansion coefficient of ferritic stainless steel is close to that of zirconia. Ferritic stainless steel has excellent heat resistance. Therefore, ferritic stainless steel is particularly preferable. But the material which comprises the said metal plate 11 is not specifically limited, You may use another metal.

  As the metal plate 11, a metal mesh may be used, or a metal foam or a porous metal may be used. When a metal mesh, a metal foam, or a porous metal is used, it is possible to increase the followability to stress when heat is applied, thereby further improving the reliability of electrical connection.

  Conductive layers 12 made of LSM are provided on the upper and lower surfaces of the metal plate 11, respectively. The conductive layer 12 is made of a cured product obtained by heat treatment of a conductive paste mainly composed of LSM powder.

A conductive sheet 13 made of an LSM sheet is provided outside the conductive layer 12. As will be described later, the conductive sheet 13 is formed using an LSM-containing composition that cannot be completely sintered in the load heat treatment step for obtaining the fuel cell stack 1. More specifically, in the present embodiment, it is an LSM powder represented by (La _0.8 Sr _0.2 ) _0.95 MnO ₃ and has a specific surface area (BET method) of 7 m ² / g. Use powder. A slurry formed by mixing the calcined powder, a binder resin, and a solvent is formed into a sheet. The obtained sheets are laminated as shown in FIG. 1 and baked by load heat treatment for stacking described later. Thus, as will be described later, the conductive sheet 13 that has not been sintered is formed.

  A conductive layer 12 is disposed on the outer surface of the conductive sheet 13. Due to the laminated structure of the conductive layer 12 and the conductive sheet 13, the upper fuel cell 2, the metal layer 11, and the lower fuel cell 2 are joined and electrically connected.

The conductive layer 12 and the conductive sheet 13 are preferably made of conductive ceramics such as LSM. Such conductive ceramics include (LaSr) MnO ₃ , (LaSr) CoO ₃ , (LaSr) (CoFe) O ₃ , MnCo ₂ O ₄ , (SmSr) CoO ₃ , (LaCa) MnO ₃ , (LaCa) At least one selected from the group consisting of CoO ₃ , (LaCa) (CoFe) O ₃ , La (NiFe) O ₃ and (LaSr) ₂ NiO ₄ can be suitably used.

  The conductive layer 12 and the conductive sheet 13 preferably contain a metal element that constitutes the metal plate 11. Thereby, the difference in thermal expansion coefficient with respect to the metal plate 11 can be reduced. The conductive layer 12 and the conductive sheet 13 are preferably made of porous conductive ceramics.

  The conductive layer 12 and the conductive sheet 13 do not necessarily have a sheet shape, and may have a lattice shape or a mesh shape having a large number of voids, or a large number of stripe portions are provided in parallel. It may be a shape. That is, as long as electrical connection is ensured, the upper power generation unit 2b and the lower power generation unit 2b do not necessarily have to be connected to each other. In particular, the surface of the fuel cell 2 generally has irregularities. Rather, it may be desirable to configure the electrical connection portion surface to have irregularities. Therefore, as described above, a lattice shape or the like may be used.

  In the present embodiment, the joint portion 4 has a laminated structure of the adhesive layer 15 and the spacer 16 in a region different from the joint portion that electrically connects the power generation portions 2b and 2c. Here, the spacer 16 is used to facilitate adhesion when the distance between the fuel cells 2 and 2 is large. As a material constituting such a spacer 16, a material having a thermal expansion coefficient close to that of the ceramic constituting the fuel cell 2 is desirable.

  In the present embodiment, the fuel cells 2 and 2 are bonded to each other via the spacer 16 by the adhesive layer 15. In this embodiment, the adhesive layer 15 is made of crystallized glass, amorphous glass, ceramics, or a mixed glass-based adhesive.

  FIG. 5 is a plan view showing the arrangement of the spacers 16 used in the fuel cell stack according to this embodiment.

  As shown in FIG. 5, the conductive portion 4a is disposed at a position corresponding to the power generation portions 2b to 2e in FIG. 3, and the spacer 16 is disposed at a position corresponding to the cross-shaped flow path constituting portion 2a in FIG. ing. The spacer 16 includes a through hole 16a constituting a fuel gas passage or a through hole 16b constituting an air passage. Thereby, the fuel gas flow path and air flow path which penetrate the upper and lower cells are secured. The spacer 16 shown in FIG. 5 has an integral structure in which all cross shapes are connected, but may be divided into a plurality of pieces, and each divided spacer may be rectangular. It may be oval.

  In the above configuration, the power generating units 2a to 2e of the upper and lower fuel cells 2 are electrically connected by disposing the conductive unit 4a including the metal plate 11 at positions corresponding to the power generating units 2a to 2e of the fuel cell 2. It is connected to the. Moreover, the heat generated from the power generation units 2a to 2e made of ceramics having low thermal conductivity can be efficiently conducted to achieve uniform heat. Uniformization enables operation at a higher current density, and higher output can be achieved.

  The reason why the spacer 16 instead of the conductive portion 4a including the metal plate 11 is arranged at a position corresponding to the cross-shaped flow path component 2a is that the fuel cell 2 made of ceramics and the metal plate 11 are heated. Since the difference in expansion coefficient is large, there is a possibility that a gap is formed in the upper and lower joints due to thermal deformation during power generation. There is no problem even if a gap is generated in the power generation units 2a to 2e, but if a gap is generated in the flow path component 2, a gas leak of fuel gas or air occurs, resulting in a decrease in fuel utilization rate and air utilization rate. For this reason, in the flow path component 2, a spacer 16 made of ceramics having a thermal expansion coefficient close to that of the fuel cell 2 (more specifically, the solid oxide electrolyte layer 7) is arranged. Specifically, the difference in coefficient of thermal expansion between the spacer 16 and the fuel cell 2 is preferably within 5%, and preferably within 2 ppm / ° C.

  The spacer 16 is formed of the same material as that of the separator 5, and may be formed of, for example, magnesia spinel, alumina, zircon, stabilized zirconia, partially stabilized zirconia, or the like.

  During power generation, the fuel cell 2 may be deformed due to factors such as a difference in thermal expansion coefficient between cell constituent materials. In such a state, a gas leak occurs between the spacer 16 and the fuel cell 2 above and below the spacer 16. In the present embodiment, the bending rigidity of the spacer 16 is reduced in order to prevent such a gas leak.

  FIG. 6 is a schematic cross-sectional view for explaining the configuration of the spacer according to the present embodiment. FIG. 7 is a schematic cross-sectional view showing the configuration of the spacer according to the comparative example shown in Patent Document 1. 6 and 7, the conductive portion 4a shown in FIG. 1 is illustrated in a simplified manner.

  As shown in FIG. 6, in the fuel cell stack 1 according to this embodiment, a plurality of spacers 16 are stacked. In this way, the spacers 16 are multilayered and the spacers 16 per sheet are made thin, so that the bending rigidity of the spacers 16 is reduced and the spacers 16 can be deformed following the cells. On the other hand, in the comparative example shown in FIG. 7, two spacers 16x are arranged.

  According to the present embodiment, with the above configuration, when one fuel cell 2 is deformed, the spacer 16 bonded to the one fuel cell 2 follows and deforms, so that leakage from the seal is suppressed. .

The bending rigidity of at least the spacer 16 joined to the fuel cell, that is, the spacer 16 arranged on the fuel cell side is preferably 350 N · mm ² or less.

  Moreover, it is preferable that the thickness of the spacer 16 is 0.7 mm or less. However, if the material and shape of the spacer 16 are changed, the preferred thickness is different.

  In particular, in this embodiment, since all the spacers 16 are thinned, the bending rigidity of the entire seal portion can be reduced, and stress is concentrated on the fuel cells 2 arranged above and below the spacers 16. It is possible to suppress the occurrence of leakage.

(Second Embodiment)
In the second and subsequent embodiments, description of matters common to the first embodiment is omitted, and only different points will be described. In particular, the same operation effect by the same configuration will not be sequentially described for each embodiment.

  FIG. 8 is a schematic cross-sectional view showing the configuration of the spacer in the fuel cell stack according to the second embodiment.

  As shown in FIG. 8, in the second embodiment, at least the spacers 16-1 and 16-2 on the fuel cell 2 side among the spacers are thinned, and deformed along with the deformation of the fuel cell 2 during power generation. Is configured to do. The bending rigidity and thickness of the spacers 16-1 and 16-2 are as described in the first embodiment. In 2nd Embodiment, the spacer 16-2 which is not arrange | positioned at the upper and lower fuel cell 2 side is not thinned. The thickness of the spacer 16-2 is adjusted to a thickness that fills the space between the fuel cells.

  According to the second embodiment, at least only the spacers 16-1 and 16-2 on the side of the fuel cell 2 are thinned, and are configured to be deformed along with the deformation of the fuel cell 2 during power generation. Since the spacers 16-1 and 16-2 joined to the fuel cell 2 are deformed as the fuel cells 2 above and below the joint 4 are deformed, stress is concentrated on the fuel cell 2. And the occurrence of leaks can be suppressed.

(Third embodiment)
FIG. 9 is a schematic cross-sectional view showing the configuration of the spacer in the fuel cell stack according to the third embodiment.

  As shown in FIG. 9, in the third embodiment, of the upper and lower fuel cells 2, only the spacer 16-1 disposed on one fuel cell 2 side is thinned, and the fuel cell 2 of the fuel cell 2 during power generation is reduced. It is comprised so that it may deform | transform with a deformation | transformation. In 3rd Embodiment, the spacer arrange | positioned at the other fuel cell 2 side is not made thin, but is set as one spacer 16-2. The thickness of the spacer 16-2 is adjusted to a thickness that fills the space between the fuel cells.

  The deformation direction of the cells is constant, and when the cells are deformed, tensile stress is applied to the upper fuel cell 2 of the joint 4 and compressive stress is applied to the lower fuel cell 2. Since the fuel battery cell 2 is a ceramic product mainly made of zirconia, it is strong against compressive stress but weak against tensile stress, and the fuel battery cell 2 above the joint 4 is relatively likely to leak. For this reason, it is possible to suppress leakage by reducing only the spacer on the side connected to the upper fuel cell 2. In addition, when convexly deforming downward, only the spacer 16 on the lower fuel cell 2 side needs to be thinned.

  According to the third embodiment, only the spacer on the side of at least one of the fuel cells 2, in particular the fuel cell 2 on which the tensile stress is likely to be applied, is thinned and deformed along with the deformation of the fuel cell 2 during power generation. By being comprised, it can suppress that a tensile stress concentrates on the fuel battery cell 2, and can suppress generation | occurrence | production of a leak.

(Fourth embodiment)
FIG. 10 is a schematic cross-sectional view showing the configuration of the spacer in the fuel cell stack according to the fourth embodiment.

  As shown in FIG. 10, in the fourth embodiment, a separate spacer 16-3 is disposed on the other (lower) fuel cell 2 side as compared with the third embodiment. Is thicker than the spacer 16-2 at the center but thicker than the spacer 16-1. The bending rigidity and thickness of the spacer 16-1 are as described in the first embodiment.

  Since the spacer 16-3 is thinner than the spacer 16-2, the spacer 16-3 has bending rigidity that is reduced to some extent. For this reason, the concentration of the compressive stress in the lower fuel cell 2 can be suppressed to some extent by arranging the spacer 16-3 with respect to the lower fuel cell 2 in FIG. Therefore, it is possible to suppress the occurrence of leakage in the lower fuel battery cell 2.

(Fifth embodiment)
FIG. 11 is a schematic cross-sectional view showing the configuration of the spacer in the fuel cell stack according to the fifth embodiment.

  The structure of the spacer shown in FIG. 11 is the structure of the spacer in the site | part provided with the through-hole 16b which comprises the air flow path shown in FIG. About the structure of the spacer in the site | part provided with the through-hole 16a which comprises the fuel gas flow path shown in FIG. 5, it is the same as that of 1st Embodiment-4th Embodiment.

  In the fifth embodiment, only the spacer 16 that forms the air flow path is thinned and multilayered, and the adhesive layer 15 is not provided between the upper and lower fuel cells 2, and the fuel cells 2 and the spacers 16 are joined. Not. The upper and lower fuel cells 2 are joined only by the joining force between the spacers forming the fuel gas flow path and the fuel cells 2.

  In the fifth embodiment, an air leakage of about several percent is allowed in the air side spacer 16. Since the air-side spacer 16 is not joined to the fuel cell 2, even if the fuel cell 2 is deformed, the stress can be released by sliding, and cracking of the fuel cell 2 can be suppressed.

(Sixth embodiment)
FIG. 12 is a schematic cross-sectional view showing the configuration of the spacer in the fuel cell stack according to the sixth embodiment.

  The structure of the spacer shown in FIG. 12 is the structure of the spacer in the site | part provided with the through-hole 16b which comprises the air flow path shown in FIG. 5 similarly to 5th Embodiment. About the structure of the spacer in the site | part provided with the through-hole 16a which comprises the fuel gas flow path shown in FIG. 5, it is the same as that of 1st Embodiment-4th Embodiment.

  In the sixth embodiment, as in the fifth embodiment, only the spacers 16 that form the air flow paths are thinned and multilayered, and the adhesive layer 15 is not provided between the upper and lower fuel cells 2, and the fuel cells 2 and the spacer 16 are not joined. The upper and lower fuel cells 2 are joined only by the joining force between the spacers forming the fuel gas flow path and the fuel cells 2.

  Furthermore, in the sixth embodiment, the sealing performance is improved by sandwiching the vermiculite-based or silicate-based gasket material 17 instead of the adhesive layer 156 between the upper and lower fuel cells 2 and the spacer 16. As a result, since the air side spacer 16 is not joined to the fuel cell 2, even if the fuel cell 2 is deformed, the stress can be released by sliding, and the fuel cell 2 is prevented from leaking. it can. Further, the presence of the gasket material between the upper and lower fuel cells 2 and the spacer 16 can improve the sealing performance.

(Seventh embodiment)
FIG. 13 is a schematic cross-sectional view showing the configuration of the spacer in the fuel cell stack according to the seventh embodiment.

  In the example shown in FIG. 13, two spacers 16-1 and 16-2 having a through hole 16 a or a through hole 16 b are laminated without the adhesive layer 15. There is no limitation on the number of spacers stacked. In the present embodiment, the spacers 16-1 and 16-2 are not flat but have a concavo-convex structure, and the spacers 16-1 and 16-2 are fitted together to form a single flat plate. It is configured.

  According to the seventh embodiment, since the spacers are not fixed by the adhesive layer, it is possible to follow the deformation of the fuel cell. Further, the plurality of spacers are fitted with each other so as not to be displaced or to prevent gas leakage.

  Various modifications can be made in the seventh embodiment. As shown in FIG. 13, it may be a tapered shape instead of a right-angled uneven structure, or may be a smooth curved uneven structure. Furthermore, as shown in FIG. 14, the number of irregularities may be increased. By increasing the number of irregularities, the path between the spacers becomes longer, which is effective in suppressing gas leakage.

  The exemplary embodiments of the present invention have been described above.

  The fuel cell stack according to this embodiment includes a plurality of solid oxide fuel cells 2 and a spacer 16 provided between one fuel cell and another fuel cell 2 and formed of ceramics. The adhesive layer 15 that bonds the one fuel cell 2 and the spacer 16, a plurality of the spacers 16 are laminated, and the spacer 16-1 disposed on the one fuel cell 2 side is It is comprised so that it may deform | transform with the deformation | transformation of the one fuel cell 2 at the time of electric power generation (FIG. 9). As a result, when the one fuel cell 2 is deformed, the spacer bonded to the one fuel cell 2 follows and deforms, so that leakage from the seal is suppressed.

According to this embodiment, the bending rigidity of the spacer 16 disposed on the one fuel cell 2 side is 350 N · mm ² or less. Thus, by reducing the bending rigidity of the spacer 16 arranged on the one fuel cell 2 side, the spacer 16-1 bonded to the one fuel cell 2 is deformed when the one fuel cell 2 is deformed. It can follow and deform.

  According to this embodiment, the thickness of the spacer 16-1 arranged on the one fuel cell 2 side is 0.7 mm or less. As a result, the bending rigidity of the spacer 16-1 arranged on the one fuel cell 2 side can be reduced, and when the one fuel cell 2 is deformed, the spacer 16-bonded to the one fuel cell 2. 1 can follow and deform.

  The solid oxide fuel cell is made of ceramics, which are weaker in tensile stress than compressive stress. For this reason, the spacer joined to the one fuel cell in which tensile stress is concentrated is configured to be deformed along with the deformation of the one fuel cell at the time of power generation. Concentration of tensile stress can be suppressed, and the occurrence of leakage is suppressed.

  In the present embodiment, all of the plurality of spacers 16 are configured to be deformed along with deformation of the fuel cell 2 during power generation (FIG. 6). Thereby, the rigidity of the bundle | flux of the some spacer 16 can be reduced, and the concentration of the stress to a fuel cell can be suppressed.

  In the present embodiment, the plurality of spacers 16 include a spacer 16 having a fuel gas flow path (through hole 16a) and a spacer 16 having an air flow path (through hole 16b) (FIG. 5) and bonded. The agent layer is provided between one fuel battery cell 2 and a spacer 16 having a fuel gas flow path, and an adhesive layer between the one fuel battery cell 2 and a spacer having an air flow path. 15 is not provided (FIG. 11). Since the air-side spacer 16 is not joined to the fuel battery cell 2, even if the fuel battery cell 2 is deformed, the stress can be released by sliding, and leakage from the seal portion can be suppressed.

  In this embodiment, the gasket material 17 is arrange | positioned between the one fuel cell 2 and the spacer 16 provided with the flow path of air (FIG. 12). The presence of the gasket material between one fuel cell 2 and the spacer 16 having the air flow path can improve the sealing performance.

  Each embodiment described above is for facilitating the understanding of the present invention, and is not intended to limit the present invention. The present invention can be changed / improved without departing from the spirit thereof, and the present invention includes equivalents thereof. In other words, those obtained by appropriately modifying the design of each embodiment by those skilled in the art are also included in the scope of the present invention as long as they include the features of the present invention. For example, each element included in each embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. Each embodiment is an exemplification, and it is needless to say that a partial replacement or combination of configurations shown in different embodiments is possible, and these are also included in the scope of the present invention as long as they include the features of the present invention. .

DESCRIPTION OF SYMBOLS 1 ... Fuel cell stack 2 ... Fuel cell 2a ... Flow path structure part 2b-2e ... Electric power generation part 4 ... Joint part 4a ... Conductive part 4b ... Seal part 5 ... Separator 5a, 5b ... Through-hole 5c ... Interconnector 6 ... Fuel Electrode layers 6a, 6b ... slit 7 ... solid oxide electrolyte layers 7a, 7b ... through hole 8 ... air electrode layers 8a, 8b ... slit 9 ... separators 9a, 9b ... through hole 9c ... interconnector 11 ... metal plate 12 ... conductive Layer 13 ... Conductive sheet 15 ... Adhesive layers 16, 16x, 16-1 to 16-3 ... Spacers 16a and 16b ... Through holes 17 ... Gasket material

Claims (8)

A plurality of solid oxide fuel cells;
A spacer provided between one fuel cell and another fuel cell and formed of ceramics;
An adhesive layer that bonds the fuel cell and the spacer,
A plurality of the spacers are stacked, and the spacer disposed on the one fuel cell side is configured to be deformed along with the deformation of the one fuel cell at the time of power generation.
Fuel cell stack. The bending rigidity of the spacer disposed on the one fuel cell side is 350 N · mm ² or less.
The fuel cell stack according to claim 1. The spacer disposed on the one fuel cell side has a thickness of 0.7 mm or less.
The fuel cell stack according to claim 1 or 2. The one fuel battery cell is deformed so that the side opposite to the spacer becomes a convex surface during power generation,
The fuel cell stack according to any one of claims 1 to 3. In addition to the spacer disposed on the one fuel cell side, the spacer disposed on the other fuel cell side is configured to be deformed along with deformation of the other fuel cell during power generation. ,
The fuel cell stack according to any one of claims 1 to 4. All of the plurality of spacers are configured to be deformed along with deformation of the fuel cell during power generation.
The fuel cell stack according to any one of claims 1 to 5. The plurality of spacers include a spacer having a fuel gas flow path and a spacer having an air flow path,
The adhesive layer is provided between the one fuel battery cell and a spacer provided with the fuel gas flow path, and between the one fuel battery cell and the spacer provided with the air flow path. No adhesive layer is provided,
The fuel cell stack according to any one of claims 1 to 6. A gasket material is disposed between the one fuel battery cell and a spacer having the air flow path.
The fuel cell stack according to claim 7.

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