JP6519352B2 - Fuel cell unit - Google Patents

Description

  The present invention relates to a fuel cell unit, and more particularly to a solid oxide fuel cell having a plurality of fuel cells each formed with a conductor for extracting an electric current generated based on a fuel electrode gas and an air electrode gas. It is about a unit.

  In this type of fuel cell unit, a metal plate for transmitting the current extracted from each fuel cell is provided between two adjacent fuel cells in the stacking direction. This metal plate doubles as a heat equalizing plate for making the temperature of each fuel cell uniform.

  However, since fine irregularities and warpage exist on the surface of the fuel cell or on the surface of the metal plate, in order to fill the minute gap between the fuel cell and the metal plate, conductivity of metal, alloy or conductive ceramic is required. Material is required separately.

  Incidentally, since the metal plate and the conductive material are exposed to a high temperature oxidizing atmosphere or reducing atmosphere, the metal plate and the conductive material are required to have resistance to the oxidizing atmosphere or reducing atmosphere in addition to heat resistance.

  In general, there is a difference in thermal expansion coefficient between the separator forming the fuel cell and the metal plate or the conductive material, and the breakage of the conductive path due to the thermal stress often becomes a problem. Therefore, in many cases, various loading mechanisms such as a spring mechanism, a screw tightening mechanism, and a binding mechanism are separately provided to apply a load so that the metal plate is in close contact with the fuel cell.

WO 2010-038869

  However, since it is necessary to provide a load mechanism in addition to the fuel cell stack, problems such as an increase in size of the fuel cell unit, complication of setting, and an increase in cost occur.

  Here, the size of the metal plate is reduced to the minimum size where the metal plate overlaps with the conductor as viewed from the stacking direction, the spacer is inserted into the vacant area secured thereby, and the inserted spacer is inserted into the upper and lower fuel cells By bonding with an adhesive, it is conceivable to prevent the destruction of the conductive path due to thermal stress.

  However, in this case, when the fuel battery cells are stacked in a fixed number of stages or more, cracks may be generated in the fuel battery cells due to the heat cycle. That is, since the thermal expansion coefficient is different between the separator forming the fuel cell and the metal plate or the conductive material, the stress caused by the heat cycle is concentrated in the vicinity of the spacer, and this stress concentration causes the fuel cell to crack. May cause it.

  Therefore, the main object of the present invention is to reduce the possibility of the fuel cell being cracked due to the difference in thermal expansion coefficient between the separator forming the fuel cell and the metal plate or the conductive material. It is to provide a unit.

  The fuel cell unit according to the present invention includes a solid electrolyte layer, a fuel electrode layer and an air electrode layer stacked via the solid electrolyte layer, and a plurality of separators stacked on the fuel electrode layer and the air electrode layer. A gas flow path extending in a direction perpendicular to the stacking direction to supply the fuel electrode gas and the air electrode gas to the fuel electrode layer and the air electrode layer, and the current generated based on the fuel electrode gas and the air electrode gas A solid oxide fuel cell unit having a plurality of fuel cells each formed with a conductor for each of the fuel cells, the fuel cell unit being positioned between two fuel cells adjacent in the stacking direction and viewed from the stacking direction A metal plate provided at a partial position overlapping the conductor and joined to each of two fuel cells by a conductive material, and a metal plate at a position between the two fuel cells and viewed from the stacking direction A spacer provided at a position to avoid and joined to each of two fuel cells, at least one of the two fuel cells has a first region overlapping with the metal plate when viewed from the stacking direction, and a stacking direction The rigidity of the second region is greater than the rigidity of the first region.

  The rigidity of the area of the fuel cell unit as viewed in the stacking direction and overlapping with the spacer exceeds the rigidity of the area as viewed from the stacking direction and overlapping with the metal plate. By this, it is possible to reduce the concern that the fuel cell will be cracked due to the difference in thermal expansion coefficient between the separator forming the fuel cell and the metal plate or the conductive material.

  Preferably, the edge of the spacer extends along the gas flow path at a position avoiding the gas flow path as viewed from the stacking direction. As a result, high rigidity is obtained in the area overlapping the spacer when viewed from the stacking direction, and the concern that a crack is generated in the gas flow path due to stress concentration on the edge portion of the spacer is reduced.

  More preferably, the gas flow path includes a first gas flow path through which the fuel electrode gas flows and a second gas flow path through which the cathode gas flows, and the edge portion extends along the first gas flow path. 2 includes a second edge portion extending along the gas flow path. As a result, for both of the fuel electrode gas and the air electrode gas, the concern about the occurrence of cracks in the gas flow path is reduced.

  Preferably, each of the plurality of fuel cells is further formed with a manifold extending in the stacking direction and injecting the anode gas and the cathode gas into the gas flow path, and the spacer is formed with a through hole communicating with the manifold. . The anode gas and the cathode gas are supplied to the manifold of the fuel cell via the through holes formed in the spacer, and the anode gas and the cathode gas are used as the anode and the cathode without changing the design of the fuel cell. Can be supplied.

  Preferably, the plurality of fuel cells are deposited so that the side surfaces orthogonal to the stacking direction are flush, and the spacer has a tip projecting outward from the side surface as viewed from the stacking direction. The load applied to the fuel cell is suppressed by causing the tip to project outward from the side surface of the fuel cell. This can further reduce the possibility of cracking in the gas flow path.

  Preferably, the spacer includes a plurality of small spacers separated from each other and formed in a stick shape. This simplifies the structure of the spacer and simplifies the handling of the spacer.

  More preferably, each of the plurality of small spacers has an end portion disposed at a position overlapping with the plurality of fuel cells as viewed from the stacking direction, and the contour of the end portion curves as viewed from the stacking direction. This reduces stress concentration at the end and further reduces the possibility of cracking in the gas flow path.

  Preferably, the spacer has an end disposed at a position overlapping the two fuel cells as viewed from the stacking direction, and the second region is an end region overlapping the end as viewed from the stacking direction; The rigidity of the end region is greater than the rigidity of the non-end region, including the non-end region that overlaps with the non-end portion in view. The stress caused by the difference in the thermal expansion coefficient also concentrates on the end of the spacer. By increasing the rigidity of the end region, it is possible to reduce the possibility of cracking in the fuel cell.

  More preferably, each of the fuel electrode layer and the air electrode layer is formed in a stick shape and has a plurality of poles arranged in parallel at equal intervals, and a stick shape and the outermost of the plurality of poles The gas flow path is disposed between the plurality of poles, and the width of the partial separator is larger than the width of the gas flow path. This reduces the risk of cracking in the fuel cell.

  According to the present invention, it is possible to reduce the concern that the fuel cell will be cracked due to the difference in thermal expansion coefficient between the separator forming the fuel cell and the metal plate or the conductive material.

  The above object, other objects, features and advantages of the present invention will become more apparent from the detailed description of the following embodiments given with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of a fuel cell unit of Example 1; It is a perspective view which shows a part of fuel cell unit disassembled. It is a perspective view which shows another part of the disassembled fuel cell unit. It is a perspective view which shows a part of fuel cell disassembled. It is a perspective view which shows another part of the disassembled fuel cell. It is a side view which expands and shows the side of the fuel cell unit shown in FIG. It is a perspective view which shows the lamination | stacking state of a fuel electrode layer, a spacer, a metal plate, and an air electrode layer. (A) is a perspective view which shows the lamination | stacking state of a fuel electrode layer, a spacer, and a metal plate, (B) is a top view which shows the lamination state of a fuel electrode layer, a spacer, and a metal plate. (A) is a perspective view which shows the lamination | stacking state of a spacer, a metal plate, and an air electrode layer, (B) is a top view which shows the lamination | stacking state of a spacer, a metal plate, and an air electrode layer. It is an enlarged plan view which shows the positional relationship of a spacer and a fuel electrode layer. It is an enlarged plan view which shows the positional relationship of a spacer and an air electrode layer. It is a top view which shows an example of the metal plate applied to the modification of Example 1, and a spacer. It is a top view which shows an example of the metal plate applied to the other modification of Example 1, and a spacer. FIG. 7 is a perspective view showing the appearance of a fuel cell unit of Example 2; It is a perspective view which shows a part of fuel cell unit disassembled. It is a perspective view which shows another part of the disassembled fuel cell unit. It is a perspective view which shows a part of fuel cell disassembled. It is a perspective view which shows another part of the disassembled fuel cell. It is a side view which expands and shows the side of the fuel cell unit shown in FIG. (A) is a perspective view which shows the lamination | stacking state of a fuel electrode layer, a spacer, and a metal plate, (B) is a top view which shows the lamination state of a fuel electrode layer, a spacer, and a metal plate. (A) is a perspective view which shows the lamination | stacking state of a spacer, a metal plate, and an air electrode layer, (B) is a top view which shows the lamination | stacking state of a spacer, a metal plate, and an air electrode layer.

Example 1
1 to 5, the fuel cell unit 10 of this embodiment is a solid oxide fuel cell unit, and includes two fuel cells 20a and 20b. The fuel cells 20a and 20b are deposited so that the side surfaces of the fuel cells 20a and 20b are flush with each other, whereby a flat fuel cell stack 12 is formed.

  Via conductors VHf, VHf,... Electrically connected to the anode AN are exposed on the upper surfaces (surfaces) of the fuel cells 20a and 20b. Further, via conductors VHa, VHa,... Electrically connected to the cathode CT are exposed on the lower surface (front surface) of each of the fuel cells 20a and 20b (see FIG. 5). The current generated based on the fuel electrode gas and the air electrode gas is extracted to the outside by via conductors VHf, VHf,... On the anode AN side and via conductors VHa, VHa,.

  In this embodiment, the X-axis, the Y-axis, and the Z-axis are assigned to the width direction, the depth direction, and the height direction of the rectangular parallelepiped that makes up the fuel cell stack 12, respectively.

  In each of the fuel cells 20a and 20b, two manifolds MFf1 and MFf2 for fuel electrode gas and two manifolds MFa1 and MFa2 for air electrode gas are also formed (see FIGS. 4 and 5). Each of manifolds MFf1, MFf2, MFa1 and MFa2 extends in the Z-axis direction inside of each of fuel cells 20a and 20b, and through holes HLf1, HLf2 formed on the upper and lower surfaces of each of fuel cells 20a and 20b. , HLa1 and HLa2 respectively.

  When viewed from the Z-axis direction, manifolds MFf1 and MFf2 are formed in a strip extending in a straight line extending in the Y-axis direction from the upper center of each of fuel cells 20a and 20b, and manifolds MFa1 and MFa2 are fuel cells 20a and 20b. Is formed in a band shape on a straight line extending in the X-axis direction from the center of the upper surface of each of.

  More specifically, the manifold MFf1 is located on the positive side in the Y-axis direction with respect to the center of the upper surface, and the manifold MFf2 is located on the negative side in the Y-axis direction with respect to the center of the upper surface. Further, the manifold MFa1 is located on the positive side in the X-axis direction with respect to the center of the upper surface, and the manifold MFa2 is located on the negative side in the X-axis direction with respect to the center of the upper surface.

  When viewed from the Z-axis direction, the through hole HLf1 is formed at a position overlapping the manifold MFf1, the through hole HLf2 is formed at a position overlapping the manifold MFf2, and the through hole HLa1 is formed at a position overlapping the manifold MFa1. The HLa 2 is formed at a position overlapping the manifold MFa 2.

  Therefore, the via conductors VHf, VHf,... On the anode AN side are divided into four on the basis of the manifolds MFf1, MFf2, MFa1 and MFa2. Similarly, the via conductors VHa, VHa,... On the cathode CT side are also divided into four based on the manifolds MFf1, MFf2, MFa1 and MFa2.

  As shown in FIGS. 4 to 5, the fuel cell 20a includes an air electrode conductor layer 121 using the separator SP1 as a base material, an air electrode layer 122 using the separator SP2 as a base material, and an electrolyte using an electrolyte EL as a base material. A layer 123, a fuel electrode layer 124 based on the separator SP4, and a fuel electrode side conductor layer 125 based on the separator SP5 are stacked in this order.

  The separator SP2 includes partial separators SP21 to SP23, and the separator SP4 includes partial separators SP41 to SP43 (details will be described later). Further, since the fuel cells 20a and 20b have the same structure, the description of the structure of the fuel cell 20b will be omitted by giving the same reference numerals to the common members.

  The via conductors VHa, VHa,... And the through holes HLf1, HLf2, HLa1, and HLa2 are provided in the separator SP1 forming the air electrode side conductor layer 121. The via conductors VHa, VHa,... Are provided at positions avoiding the through holes HLf1, HLf2, HLa1 and HLa2 and further avoiding the manifolds MFf1, MFf2, MFa1 and MFa2 as viewed from the Z-axis direction. Further, one end and the other end of the via conductors VHa, VHa,... Are exposed on the upper surface and the lower surface of the separator SP1, respectively.

  The via conductors VHf, VHf,... And the through holes HLf1, HLf2, HLa1 and HLa2 are provided in the separator SP5 forming the fuel electrode side conductor layer 125. Each of the via conductors VHf, VHf,... Is provided at a position avoiding the through holes HLf1, HLf2, HLa1 and HLa2 and further avoiding the manifolds MFf1, MFf2, MFa1 and MFa2 as viewed from the Z-axis direction. Further, one end and the other end of via conductor VHf are exposed on the upper surface and the lower surface of separator SP5, respectively.

  In the air electrode layer 122, the partial separators SP21 to SP23 are formed in a stick shape with a common thickness. Partial separator SP21 extends in the Y-axis direction at the negative end in the X-axis direction, partial separator SP22 extends in the Y-axis at the central position in the X-axis direction, and partial separator SP23 is the positive end in the X-axis direction The position of the part extends in the Y-axis direction.

  The width of the partial separator SP21 coincides with the width of the partial separator SP23, and the width of the partial separator SP22 is approximately twice the width of each of the partial separators SP21 and SP23. The manifolds MFf1 and MFf2 are provided in the partial separator SP22.

  In a region sandwiched by the partial separators SP21 to SP23, a plurality of cathodes (air electrodes) CT, CT, ... having the same thickness as the thickness of the partial separators SP21 to S23 and formed in a stick shape are provided. Each of the cathodes CT, CT,... Has a length smaller than half of the length of the air electrode layer 122 in the Y-axis direction, and extends in the Y-axis direction at a predetermined distance in the X-axis direction. .

  The negative end surface of the cathodes CT, CT,... Is provided so as to be flush with the negative end surface of the partial separators SP21 to SP23 in the Y-axis direction. The other end of cathodes CT, CT,... Is provided so that the end face on the positive side in the Y-axis direction is flush with the end face on the positive side in the Y-axis direction of partial separators SP21 to SP23.

  Via conductors VHa, VHa,... Are provided in parts of cathodes CT, CT,. The via conductors VHa, VHa,... Extend in the Z-axis direction and are exposed on the upper and lower surfaces of the cathodes CT, CT,. Further, when viewed from the Z-axis direction, the via conductors VHa, VHa,... Provided in the air electrode layer 122 overlap the via conductors VHa, VHa,.

  The manifolds MFa1 and MFa2 are formed by the cathodes CT, CT,... And the partial separators SP21 to SP23. Further, gas channels GRa, GRa,... For air electrodes extending in the Y-axis direction are formed between the cathodes CT, CT,. That is, when viewed along the X-axis, the cathodes CT and the gas channels GRa are alternately arranged.

  In fuel electrode layer 124, partial separators SP41 to SP43 have a common thickness and are formed in a stick shape. Partial separator SP41 extends in the X axis direction at the negative end in the Y axis direction, partial separator SP22 extends in the X axis direction at the center position in the Y axis, and partial separator SP23 is the positive end in the Y axis direction The position of the part extends in the X-axis direction.

  The width of the partial separator SP41 matches the width of the partial separator SP43, and the width of the partial separator SP42 is approximately twice the width of each of the partial separators SP41 and SP43. The manifolds MFa1 and MFa2 are provided to the partial separator SP42.

  In the region sandwiched by the partial separators SP41 to SP43, a plurality of anodes (fuel electrodes) AN, AN,... Having the same thickness as the thickness of the partial separators SP41 to S43 and formed in a stick shape are provided. Each of the anodes AN, AN,... Has a length smaller than half of the length of the fuel electrode layer 124 in the X-axis direction, and extends in the X-axis direction at a predetermined distance in the Y-axis direction. .

  The anodes AN, AN,... Are provided such that the end face on the negative side in the X-axis direction is flush with the end face on the negative side in the X-axis direction of the partial separators SP41 to SP43. In addition, the other end of anodes AN, AN,... Is provided so that the end face on the positive side in the X-axis direction is flush with the end face on the positive side in the X-axis direction of partial separators SP41 to SP43.

  Via conductors VHf, VHf,... Are provided in parts of anodes AN, AN,. The via conductors VHf, VHf,... Extend in the Z-axis direction and are exposed on the upper and lower surfaces of the anodes AN, AN,. Further, when viewed from the Z-axis direction, the via conductors VHf, VHf,... Provided in the fuel electrode layer 124 overlap the via conductors VHf, VHf,.

  Manifolds MFf1 and MFf2 are formed by anodes AN, AN,... And partial separators SP41 to SP43. Further, between anodes AN, AN,... Aligned in the X-axis direction, gas flow paths GRf, GRf,. That is, when viewed along the Y axis, the anodes AN and the gas channels GRf are alternately arranged.

  The electrolyte layer 123 is formed by forming manifolds MFf1, MFf2, MFa1, and MFa2 in the electrolyte EL. The upper surfaces of the cathodes CT, CT,... Provided on the air electrode layer 122 are disposed on the lower surface of the electrolyte layer 123, and the lower surfaces of the anodes AN, AN,... Provided on the fuel electrode layer 124 are disposed on the upper surface of the electrolyte layer 123 Be done.

  Returning to FIG. 2, the current collector 16 a is formed of four small current collectors 161 a to 164 a. The area of the upper surface or the lower surface of each of the small current collecting plates 161a to 164a is slightly smaller than 1/4 of the area of the upper surface or the lower surface of the fuel cell 20a. Moreover, the current collection board 16b shown in FIG. 3 is formed of four small current collection boards 161b-164b. The area of the upper or lower surface of each of the small current collectors 161b to 164b is also slightly smaller than 1⁄4 of the area of the upper or lower surface of the fuel cell 20b.

  The small current collecting plate 161a is disposed on the X axis direction positive side and the Y axis direction positive side of the upper surface of the fuel cell 20a so that the lower surface thereof faces a part of the via conductors VHf, VHf,. Ru. The small collector plate 162a is positioned on the X axis direction negative side and the Y axis direction positive side of the upper surface of the fuel cell 20a so that the lower surface thereof faces the other part of the via conductors VHf, VHf,. Will be distributed.

  The small current collecting plate 163a is located on the X axis direction negative side and the Y axis direction negative side of the upper surface of the fuel cell 20a so that the lower surface thereof faces the other part of the via conductors VHf, VHf,. Will be distributed. The small current collecting plate 164a is a position on the X axis direction positive side and the Y axis direction negative side of the upper surface of the fuel cell 20a such that the lower surface faces the other part of the via conductors VHf, VHf,. Will be distributed.

  The small current collecting plate 161b is disposed on the X axis direction positive side and the Y axis direction positive side of the lower surface of the fuel cell 20b such that the upper surface thereof faces a part of the via conductors VHa, VHa,. Ru. The small collector plate 162b is positioned on the X axis direction negative side and the Y axis direction positive side of the lower surface of the fuel cell 20b so that the upper surface faces the other part of the via conductors VHa, VHa,. Will be distributed.

  The small current collecting plate 163b is located on the negative side of the lower surface of the fuel cell 20b in the X-axis direction and on the negative side in the Y-axis direction so that the upper surface faces the other part of the via conductors VHa, VHa,. Will be distributed. The position of the small current collecting plate 164b on the X axis direction positive side and the Y axis direction negative side of the lower surface of the fuel cell 20b such that the upper surface faces the other part of the via conductors VHa, VHa,. Will be distributed.

  Thus, the small current collecting plates 161a to 164a, ie, the current collecting plate 16a, are electrically connected to the via conductors VHf, VHf,..., And the small current collecting plates 161b to 164b, ie, the current collecting plate 16b are: via conductors VHa, VHa,. And electrically connected.

  The upper surface or lower surface of the fixing plate 14 a has an area substantially matching the area of the upper surface of the fuel cell stack 12, and the upper surface or lower surface of the fixing plate 14 b has an area substantially matching the area of the lower surface of the fuel cell stack 12.

  The fixed plate 14a is disposed on the upper surface of the current collector plate 16a such that a portion of the lower surface thereof faces the upper surface of the current collector plate 16a. The fixed plate 14b is disposed on the lower surface of the current collector plate 16b such that a portion of the upper surface thereof faces the lower surface of the current collector plate 16b. Here, the side surface of each of the fixing plates 14 a and 14 b is flush with the side surface of the fuel cell stack 12 (although it is not essential to be flush). Further, manifolds MFf1, MFf2, MFa1 and MFa2 are formed for the fixing plate 14b. Current collectors 16a and 16b are fixed by fixing plates 14a and 14b arranged in this manner.

  The spacer 18a is positioned at a position where the current collector plate 16a is missing so as to adjust the distance from the upper surface of the fuel cell 20a to the lower surface of the fixed plate 14a to the same distance as the thickness of the current collector plate 16a. It is arranged between the fixing plate 14a. The spacer 18b is fixed to the fuel cell 20b at a position where the current collector plate 16b is missing so as to adjust the distance from the lower surface of the fuel cell 20b to the upper surface of the fixed plate 14b to the same distance as the thickness of the current collector 16b. It is disposed between the plate 14b.

  At this time, the lower surface of the spacer 18a faces the upper surface of the fuel cell 20a, and the upper surface of the spacer 18a faces the lower surface of the fixing plate 14a. Similarly, the upper surface of the spacer 18b faces the lower surface of the fuel cell 20b, and the lower surface of the spacer 18a faces the upper surface of the fixing plate 14b.

  Also, since each of the current collectors 16a and 16b is arranged as described above, the upper surface or the lower surface of each of the spacers 18a and 18b forms a cross. As for the spacer 18b, four through holes THf1, THf2, THa1 and THa2 communicating with the manifolds MFf1, MFf2, MFa1 and MFa2, respectively, are formed. The tip of each of the spacers 18a and 18b protrudes outward beyond the side surface of the fuel cell stack 12 (details will be described later).

  A metal plate 22 is disposed between the fuel cells 20a and 20b. The metal plate 22 transmits the current extracted from the fuel cells 20a and 20b to the current collectors 16a and 16b, and makes the temperatures of the fuel cells 20a and 20b uniform.

  The metal plate 22 is also formed by the four small metal plates 221 to 224. The area of the upper surface or the lower surface of each of the small metal plates 221 to 224 is slightly smaller than 1⁄4 of the area of the upper surface or the lower surface of each of the fuel cells 20a and 20b.

  Between the fuel cells 20a and 20b, the small metal plate 221 has its upper surface facing part of the via conductors VHa, VHa,... And its lower surface facing part of the via conductors VHf, VHf,. Are disposed on the X axis direction positive side and the Y axis direction positive side. The small metal plate 222 has the top surface facing the other part of the via conductors VHa, VHa,... And the bottom surface thereof facing the other part of the via conductors VHf, VHf,. And 20b between the X axis direction negative side and the Y axis direction positive side.

  The small metal plate 223 has the upper surface facing the other part of the via conductors VHa, VHa,... And the lower surface thereof the other part of the via conductors VHf, VHf,. And 20b between the X axis direction negative side and the Y axis direction negative side. The small metal plate 224 has a top surface facing the other part of the via conductors VHa, VHa,... And a bottom surface thereof facing the other part of the via conductors VHf, VHf,. The cells 20a and 20b are disposed on the X axis direction positive side and the Y axis direction negative side.

  Via conductors VHa, VHa,... Provided in fuel cell 20a are electrically connected to via conductors VHf, VHf,... Provided in fuel cell 20b via metal plate 22 arranged in this manner. .

  In order to adjust the distance from the lower surface of the fuel cell 20a to the upper surface of the fuel cell 20b to a distance equivalent to the thickness of the metal plate 22, the spacer 24 of the fuel cells 20a and 20b Placed between. At this time, the upper surface of the spacer 24 faces the lower surface of the fuel cell 20a, and the lower surface of the spacer 24 faces the upper surface of the fuel cell 20b.

  Further, since the metal plate 22 is disposed as described above, the upper surface or the lower surface of the spacer 24 makes a cross. Further, four through holes THf1, THf2, THa1 and THa2 communicating with the manifolds MFf1, MFf2, MFa1 and MFa2, respectively, are formed in the spacer 24. The tip of the spacer 24 protrudes outward beyond the side surface of the fuel cell stack 12 (details will be described later).

  As can be seen from FIG. 6, a conductive material 26 is disposed between the upper surface of the fuel cell 20a and the lower surface of the current collector 16a. The conductive material 26 is also disposed between the lower surface of the fuel cell 20b and the upper surface of the current collector 16b. A minute gap formed between the fuel cell 20 a and the current collector plate 16 a or between the fuel cell 20 b and the current collector plate 16 b is filled with the conductive material 26.

  Further, an adhesive 28 is disposed between the upper surface of the fuel cell 20a and the lower surface of the spacer 18a, and between the lower surface of the fixing plate 14a and the upper surface of the spacer 18a. The adhesive 28 is also disposed between the lower surface of the fuel cell 20b and the upper surface of the spacer 18b, and between the upper surface of the fixing plate 14b and the lower surface of the spacer 18b. As a result, the fixed plate 14a is fixed to the fuel cell 20a via the spacer 18a, and the fixed plate 14b is fixed to the fuel cell 20b via the spacer 18b.

  Furthermore, a conductive material 26 is disposed between the lower surface of the fuel cell 20 a and the upper surface of the metal plate 22. The conductive material 26 is also disposed between the upper surface of the fuel cell 20 b and the lower surface of the metal plate 22. The minute gaps generated between the metal plate 22 and each of the fuel cells 20 a and 20 b are filled with the conductive material 26.

  The adhesive 28 is disposed between the lower surface of the fuel cell 20a and the upper surface of the spacer 24, and the adhesive 28 is also disposed between the upper surface of the fuel cell 20b and the lower surface of the spacer 24. As a result, the fuel cells 20 a and 20 b are fixed to each other through the spacer 24.

  The fixed plates 14a to 14b and the spacers 18a to 18b, 24 are made of 3YSZ (yttria stabilized zirconia). The separators SP1 to SP5 forming each of the fuel cells 20a and 20b are also made of 3YSZ. Therefore, the thermal expansion coefficients are the same among the fixed plates 14a-14b, the spacers 18a-18b, 24 and the separators SP1-SP5. The current collectors 16a to 16b and the metal plate 22 are made of ferritic stainless steel, and the conductive material 26 is made of LSM (lanthanum strontium manganite) which is a conductive ceramic.

  The difference in thermal expansion coefficient among the fixed plates 14a-14b, the spacers 18a-18b, 24 and the separators SP1-SP5 is preferably within 5%. Further, the difference in thermal expansion coefficient between each of fixing plates 14a-14b, spacers 18a-18b, 24 and separators SP1-SP5 and each of current collector plates 16a-16b and metal plate 22 is within 2 ppm / ° C. It is assumed.

  Basically, the materials of the current collectors 16a to 16b, the metal plate 22 and the conductive material 26 can be arbitrarily selected from metals, alloys or conductive ceramics. However, thermal stress is generated in the fuel cell units 20a to 20b, the current collectors 16a to 16b and the metal plate 22 in an environment where the fuel cell unit 10 operates.

  Therefore, the material of the conductive material 26 has a thermal expansion coefficient close to the thermal expansion coefficient of the fixed plates 14a-14b, the spacers 18a-18b, 24 and the separators SP1-SP5 from the viewpoint of suppressing thermal stress and thus avoiding connection failure. It is preferable to use it as a material.

  From the viewpoint of suppressing the electrical resistance, the conductive material 26 is preferably a conductive ceramic based on LaSrMnO3, LaCrO3, LaCoO3, MnCoO3 or the like, and if it is a noble metal, Ag, Pd, Au, Pt, Rh , Ru or an alloy of two or more of them is preferable.

  In addition, the conductive material 26 has a minute gap formed between the fuel cell 20a and the current collector plate 16a, a minute gap formed between the fuel cell 20b and the current collector plate 16b, and the metal plate 22. It is arranged to fill a minute gap generated between each of the fuel cells 20a and 20b. Therefore, the conductive material 26 has a structure (a mesh structure, a felt structure, a sponge structure, a porous structure or the like that can be easily deformed) that relieves the thermal stress. In addition, the conductive material 26 may be configured of a conductive sheet having such a structure and a conductive paste applied on both sides thereof.

  The adhesive 28 is made of crystallized glass and softens at around 700 ° C. and crystallizes at 900 to 1000 ° C. The softened and crystallized adhesive 28 is in close contact with the fixing plates 14a-14b, the spacers 18a-18b, 24 and the fuel cells 20a-20b. As a result, the fixing plate 14a is fixed to the fuel cell 20a through the spacer 18a, the fixing plate 14b is fixed to the fuel cell 20b through the spacer 18b, and the fuel cells 20a and 20b are through the spacer 24. Stick together.

  The cathode gas flowing through the manifolds MFa1 and MFa2 is discharged to the outside of the fuel cell stack 12 through the gas flow paths GRa, GRa,. The fuel electrode gas having flowed through the manifolds MFf1 and MFf2 is discharged to the outside of the fuel cell stack 12 through the gas flow paths GRf, GRf,.

The cathode gas comes in contact with the cathodes CT1 to CT4 when flowing through the manifolds MFa12, MFa22 and the gas flow paths GRa, GRa,. Further, the fuel electrode gas comes in contact with the anodes AN1 to AN4 when flowing through the manifolds MFf14, MFf24 and the gas flow paths GRf, GRf,. The cathode gas and the anode gas undergo chemical reactions according to chemical formulas 1 and 2, and as a result, positive and negative voltages appear on both sides of the electrolyte EL.
[Chemical formula 1]
^{_{1 / 2O 2 + 2e - →}} O 2-
[Chemical formula 2]
H ₂ + O ^2- → H ₂ O + 2 e ⁻

  The cathode electrode gas and a part of the anode electrode gas are discharged outside the fuel cells 20a and 20b without causing a chemical reaction. The cathode gas is discharged through a plurality of gas flow paths GRa, GRa,... Alternately formed with a plurality of cathodes CT, CT,. Further, the fuel electrode gas is discharged through a plurality of gas flow paths GRf, GRf,... Alternately formed with a plurality of anodes AN, AN,. The discharged cathode electrode gas and fuel electrode gas react with each other to generate heat, thereby achieving thermal independence.

  The fuel electrode layer 124 constituting the fuel cell 20b, the metal plate 22 and the spacer 24 provided between the fuel cells 20a to 20b, and the air electrode layer 122 constituting the fuel cell 20a are shown in FIG. Stacked on.

  Among these, FIGS. 8A and 8B show the fuel electrode layer 124, the metal plate 22 and the spacer 24 in a perspective view and a plan view, and the metal plate 22, the spacer 24 and the air electrode layer 122 in a perspective view and FIG. The state which planarly viewed is shown to FIG. 9 (A) and FIG. 9 (B). Furthermore, FIG. 10 shows a state in which a part of the laminated structure depicted in FIG. 8B is enlarged, and FIG. 11 shows a state in which a part of the laminated structure depicted in FIG.

  As can be seen from FIGS. 8B and 9B, of the regions forming each of the fuel cells 20a and 20b, the region overlapping the metal plate 22 as viewed from the Z-axis direction is the “first region RG1”. A region overlapping with the spacer 24 as viewed in the Z-axis direction is taken as a "second region RG2". Further, the spacer 24 has four tips 24p, 24p,..., And any tip 24p protrudes outward beyond the side surfaces of the fuel cells 20a and 20b.

  Furthermore, as can be seen from FIGS. 10 and 11, the spacer 24 has edge portions EGf1 and EGf2 extending along the anodes AN, AN,... Or the gas flow paths GRf, GRf,. It has edge parts EGa1 and EGa2 extending along the gas flow paths GRa, GRa,.

  Among these, the edge portions EGf1 and EGf2 extend in the X-axis direction from a position overlapping with the partial separator SP42 (that is, a position avoiding the gas flow path GRf) as viewed from the Z-axis direction. Further, the edge portions EGa1 and EGa2 extend in the Y-axis direction from a position overlapping with the partial separator SP22 (that is, a position avoiding the gas flow path GRa) as viewed from the Z-axis direction.

  As described above, the metal plate 22 is bonded to each of the fuel cells 20a and 20b by the conductive material 26, and the spacer 24 is bonded to each of the fuel cells 20a and 20b by the adhesive 28, the thermal expansion coefficient is Edge portions EGf1, EGf2, EGa1 of the spacers 24 joined to the fuel cells 20a, 20b are different because the separators SP1 to SP5 respectively forming the fuel cells 20a, 20b are different from the metal plate 22 or the conductive material 26. Or tensile stress concentrates on EGa2. On the other hand, in the fuel cells 20a and 20b, the strength of the position where the gas flow paths GRf, GRf,... Or the gas flow paths GRa, GRa,.

  As a result, when the edge portions EGf1 and EGf2 overlap with the gas flow paths GRf, GRf, ... as viewed from the Z-axis direction, or the edge portions EGa1 and EGa2 overlap with the gas flow paths GRa, GRa, ... as viewed from the Z-axis direction In this case, concentration of tensile stress on the edge portions EGf1, EGf2, EGa1 or EGa2 may cause a crack in the gas flow path GRf or GRa.

  According to this embodiment, the edge portions EGf1, EGf2 extend along the gas flow paths GRf, GRf,... So as to avoid the gas flow paths GRf, GRf,. The position which avoids the gas flow paths GRa, GRa,... Also extends along the gas flow paths GRa, GRa,. As a result, in the fuel cells 20a and 20b, the rigidity of the second region RG2 exceeds that of the first region RG1.

  Thereby, the gas flow paths GRf, GRf,... Or the gas flow due to the difference in the thermal expansion coefficient between the separators SP1 to SP5 forming each of the fuel cells 20a, 20b and the metal plate 22 or the conductive material 26. It is possible to reduce the possibility of cracking in the roads GRa, GRa,.

  Further, in this embodiment, when viewed from the Z-axis direction, the tip 24p of the spacer 24 protrudes outward beyond the side surfaces of the fuel cells 20a and 20b. By designing to allow such protrusion in advance, it is possible to increase the margin of the variation of the dimension of the spacer 24 and the variation of the positional accuracy at the time of arrangement.

  Furthermore, the tensile stress due to the difference in thermal expansion coefficient is also concentrated on the tip 24p of the spacer 24. By making the tip 24p project outward from the side surfaces of the fuel cells 20a and 20b, the fuel cell 20a And 20b are suppressed. As a result, it is possible to further reduce the concern that the gas flow paths GRf, GRf,... Or the gas flow paths GRa, GRa,.

  In this embodiment, the edge portions EGf1 and EGf2 extend in the X-axis direction at a position overlapping the partial separator SP42 as viewed from the Z-axis direction. Further, the edge portions EGa1 and EGa2 extend in the Y-axis direction at a position overlapping the partial separator SP22 as viewed from the Z-axis direction.

  However, the position where the edge portions EGf1 and EGf2 extend along the X axis may be a position overlapping with the anodes AN, AN... When viewed from the Z axis direction. Similarly, the position where the edge portions EGa1 and EGa2 extend along the Y axis may be a position overlapping the cathodes CT, CT,... As viewed from the Z axis direction.

  Further, in this embodiment, the spacer 24 is integrally formed so as to draw a cross when viewed from the Z-axis direction. However, as shown in FIG. 12, the spacer 24 may be divided into four small spacers 24f1, 24f2, 24a1 and 24a2.

  According to FIG. 12, the small spacers 24f1, 24f2, 24a1 and 24a2 respectively correspond to the four cross-shaped pieces. Also, focusing on the insertion end of each of the small spacers 24f1, 24f2, 24a1 and 24a2 (the end on the side overlapping with each of the fuel cells 20a and 20b as viewed from the Z-axis direction), the insertion end is viewed from the Z-axis direction. It is arranged at a position avoiding the gas flow paths GRf and GRf (see also FIG. 8 (B) and FIG. 9 (B)), and the contour of the insertion end draws a curve as viewed from the Z-axis direction.

  By dividing the spacer 24 in this manner, the structure of the spacer 24 is simplified and the arrangement of the spacer 24 is simplified. Further, by arranging the insertion ends of the small spacers 24f1, 24f2, 24a1 and 24a2 at positions away from the gas flow paths GRf and GRf and forming a curved shape, stress concentration on the insertion ends is alleviated. In addition, the concern that the gas flow paths GRf and GRf are cracked can be reduced.

  Furthermore, in this embodiment, the tip 24p of the spacer 24 is made to project outward beyond the side surfaces of the fuel cells 20a and 20b. However, as shown in FIG. 13, if the tip 24p has a curved shape, stress concentration on the tip 24p is alleviated, so that the tip 24p can be accommodated inside the side surfaces of the fuel cells 20a and 20b.

Example 2
With reference to FIGS. 14 to 18, the fuel cell unit 10 'of this embodiment is a solid oxide fuel cell unit having substantially the same structure as the fuel cell unit 10 described above. In addition, the material of each member forming the fuel cell unit 10 'matches the material of each member forming the fuel cell unit 10. Therefore, in the following, different structures are mainly described, and redundant description of similar structures is omitted as much as possible. Further, among the members constituting the fuel cell unit 10 ', the members similar to the members constituting the fuel cell unit 10 are denoted by the same reference numerals, and redundant descriptions will be omitted as much as possible.

  In the fuel cell unit 10 'of this embodiment, as shown in FIGS. 17 to 18, the width of each of the partial separators SP21' and SP23 'substantially matches the width of the partial separator SP22', and the partial separators SP41 'and SP43 The width of each of 'substantially coincides with the width of the partial separator SP42'.

  As a result, the upper or lower surface of the air electrode layer 122 ′ is wider than the upper or lower surface of the air electrode layer 122, and the upper or lower surface of the fuel electrode layer 124 ′ is also wider than the upper or lower surface of the fuel electrode layer 124. Further, the width of each of the partial separators SP21 ′ and SP23 ′ is larger than the width of each of the gas flow paths GRa ′, GRa ′,. Similarly, the width of each of the partial separators SP41 ′ and SP43 ′ is larger than the width of each of the gas flow paths GRf ′, GRf ′,.

  Furthermore, the side surfaces of each of the fuel cells 20a 'and 20b' are flush. As a result, the upper or lower surface of the air electrode conductor layer 121 'is wider than the upper or lower surface of the air electrode conductor layer 121, and the upper or lower surface of the electrolyte layer 123' is wider than the upper or lower surface of the electrolyte layer 123. The upper surface or the lower surface of the pole-side conductor layer 125 ′ is wider than the upper surface or the lower surface of the fuel electrode-side conductor layer 125.

  A current collector 16a 'disposed between the fixed plate 14a' and the fuel cell 20a 'is formed by four small current collectors 161a' to 164a '. The area of the upper surface or the lower surface of each of the small current collecting plates 161a 'to 164a' is increased by the width of each of the partial separators SP21 ', SP23', SP41 ', and SP43' being increased.

  When viewed from the Z-axis direction, the rectangle circumscribing the small collector plates 161a 'to 164a' overlaps the contour of the fuel cell 20a '. On the other hand, the size of the cross-shaped air gap that appears between the small current collectors 161a 'to 164a' when viewed from the Z-axis direction is smaller than the current collectors 161a to 164a when viewed from the Z-axis. Match the size of the air gap that appears between

  Similarly, the current collector 16b 'disposed between the fuel cell 20b' and the fixed plate 14b 'is formed by four small current collectors 161b' to 164b '. The area of the upper or lower surface of each of the small current collecting plates 161b 'to 164b' is increased by the width of each of the partial separators SP21 ', SP23', SP41 ', and SP43' being increased.

  When viewed from the Z-axis direction, the rectangle circumscribing the small collector plates 161b 'to 164b' overlaps the contour of the fuel cell 20b '. On the other hand, the size of the cross-shaped air gap appearing between the small current collectors 161b 'to 164b' when viewed from the Z axis direction is smaller than the current collectors 161b to 164b when viewed from the Z axis. Match the size of the air gap that appears between

  The metal plate 22 'disposed between the fuel cells 20a' and 20b 'is also formed by four small metal plates 221'-224'. The area of the upper surface or the lower surface of each of the small metal plates 221 ′ to 224 ′ is also increased by an increase in the width of each of the partial separators SP21 ′, SP23 ′, SP41 ′, and SP43 ′.

  When viewed from the Z-axis direction, the rectangle circumscribing the small metal plates 221 ′ to 224 ′ overlaps the outline of the fuel cell 20a or 20b. On the other hand, the size of the cross-shaped air gap appearing between the small metal plates 221'-224 'when viewed from the Z-axis direction is between the small metal plates 221-224 when viewed from the Z-axis direction. This corresponds to the size of the air gap appearing in

  In addition, the thickness of the small collector plates 161a 'to 164a' is approximately twice that of the small collector plates 161a to 164a, and the thickness of the small collector plates 161b 'to 164b' is that of the small collector plates 161b to 164b. The thickness is approximately twice, and the thickness of the small metal plates 221 ′ to 224 ′ is approximately twice the thickness of the small metal plates 221 to 224.

  The spacers 18a 'disposed between the fixed plate 14a' and the fuel cells 20a 'at the position where the current collectors 16a' are missing are each approximately half the thickness of the current collectors 16a '. And the spacers 181a and 182a stacked in the Z-axis direction.

  Here, the upper surface of the spacer 181a faces the lower surface of the fixed plate 14a ', the lower surface of the spacer 181a faces the upper surface of the spacer 182a, and the lower surface of the spacer 182a faces the upper surface of the fuel cell 20a'. Further, the tip end face (= the face orthogonal to the X or Y axis) of the spacer 181a or 182a is flush with the side face of the fuel cell 20a ′. Further, the width of the cross formed by each of the spacers 181a and 182a is substantially equal to the width of the cross formed by the spacer 18a.

  The spacers 18b 'disposed between the fuel cell 20b' and the fixed plate 14b 'at the position where the current collector plate 16b' is missing have a thickness of approximately half the thickness of the current collector plate 16b ', each having a thickness of And the spacers 181b and 182b stacked in the Z-axis direction.

  Here, the top surface of the spacer 181b faces the bottom surface of the fuel cell 20b ', the bottom surface of the spacer 181b faces the top surface of the spacer 182b, and the bottom surface of the spacer 182b faces the top surface of the fixed plate 14b'. Further, the tip end face (= the face orthogonal to the X or Y axis) of the spacer 181b or 182b is flush with the side face of the fuel cell 20b '. Further, the width of the cross formed by each of the spacers 181 b and 182 b is substantially the same as the width of the cross formed by the spacer 18 b.

  The spacers 24 'disposed between the fuel cells 20a' and 20b 'at the position where the metal plate 22' is missing each have a thickness of about half the thickness of the metal plate 22 'and are in the Z-axis direction Are constituted by the spacers 241 and 242 laminated to each other.

  Here, the upper surface of the spacer 241 faces the lower surface of the fuel cell 20a ', the lower surface of the spacer 241 faces the upper surface of the spacer 242, and the lower surface of the spacer 242 faces the upper surface of the fuel cell 20b'. Further, the tip end surface (= surface perpendicular to the X or Y axis) of the spacer 241 or 242 is flush with the side surface of each of the fuel cells 20a ′ and 20b ′. Furthermore, the width of the cross formed by each of the spacers 241 and 242 is substantially the same as the width of the cross formed by the spacer 24.

  In addition, four through holes THf1 ', THf2', THa1 'and THa2' respectively communicating with the manifolds MFf1 ', MFf2', MFa1 'and MFa2' are formed in the current collecting plate 16b 'and the metal plate 22' respectively. Be done.

  As can be seen from FIG. 19, a conductive material 26 'is disposed between the upper surface of the fuel cell 20a' and the lower surface of the current collector 16a '. A conductive material 26 'is also disposed between the lower surface of the fuel cell 20b' and the upper surface of the current collector 16b '. A minute gap generated between the fuel cell 20a 'and the current collector 16a' or between the fuel cell 20b 'and the current collector 16b' is filled with the conductive material 26 '.

  Also, bonding is performed between the lower surface of the fixed plate 14a 'and the upper surface of the spacer 181a, between the lower surface of the spacer 181a and the upper surface of the spacer 182a, and between the lower surface of the spacer 182a and the upper surface of the fuel cell 20a'. Agent 28 'is dispensed. The adhesive 28 'is disposed between the lower surface of the fuel cell 20b' and the upper surface of the spacer 181b, between the lower surface of the spacer 181b and the upper surface of the spacer 182b, and between the lower surface of the spacer 182b and the upper surface of the fixing plate 14b '. Is also distributed.

  As a result, the fixed plate 14a 'is fixed to the fuel cell 20a' through the spacers 181a and 182a, and the fixed plate 14b 'is fixed to the fuel cell 20b' through the spacers 181b and 182b.

  Further, a conductive material 26 'is disposed between the lower surface of the fuel cell 20a' and the upper surface of the metal plate 22 '. A conductive material 26 'is also disposed between the upper surface of the fuel cell 20b' and the lower surface of the metal plate 22 '. The minute gaps formed between the metal plate 22 'and each of the fuel cells 20a' and 20b 'are filled with the conductive material 26'.

  Further, between the lower surface of the fuel cell 20a 'and the upper surface of the spacer 241, between the lower surface of the spacer 241 and the upper surface of the spacer 242, and between the lower surface of the spacer 242 and the upper surface of the fuel cell 20b' An adhesive 28 'is dispensed. As a result, the fuel cells 20a 'and 20b' are fixed to each other through the spacers 241 and 242.

  20A and 20B show the fuel electrode layer 124 ', the metal plate 22' and the spacer 24 'in a perspective view and a plan view, respectively, showing the metal plate 22', the spacer 24 'and the air electrode layer 122'. 21 (A) and 21 (B) show a perspective view and a plan view of FIG.

  As can be seen from FIGS. 20 (B) and 21 (B), of the regions forming each of the fuel cells 20a ′ and 20b ′, the region overlapping the metal plate 22 ′ as viewed from the Z-axis direction A region overlapping with the spacer 24 'as viewed from the Z-axis direction is referred to as a "second region RG2'".

  Further, the end 24p 'of the spacer 24' overlaps the fuel cell 20a 'or 20b' when viewed from the Z-axis direction, and in the second region RG2 ', the area overlaps with the end 24p' when viewed from the Z-axis Is an “end portion region RGp”, and a region overlapping the portion other than the end portion 24p ′ when viewed from the Z-axis direction is a “non-end portion region RGn”.

  Furthermore, the width of the partial separator SP21 'or SP23' is approximately twice the width of the partial separator SP21 or SP23, and the width of the partial separator SP41 'or SP43' is also approximately twice the width of the partial separator SP41 or SP43. Therefore, the stiffness of the end region RGp is greater than the stiffness of the non-end region RGn.

  As described above, the metal plate 22 'is joined to each of the fuel cells 20a' and 20b 'by the conductive material 26', and the spacer 24 'is joined to each of the fuel cells 20a' and 20b 'by the adhesive 28'. The thermal expansion coefficient is different between the separators SP1 'to SP5' forming the fuel cells 20a 'and 20b' and the metal plate 22 'or the conductive material 26'. Such a difference in thermal expansion coefficient causes stress due to the heat cycle to be concentrated in the vicinity of the spacer 24 ', and this stress concentration causes the fuel cell 20a' or 20b 'to crack.

  Based on this, in this embodiment, the rigidity of the end region RGp is made higher than the rigidity of the non-end region RGn. As a result, due to the difference in the thermal expansion coefficient between the separators SP1 'to SP5' forming the fuel cell units 20a 'and 20b' and the metal plate 22 'or the conductive material 26', the fuel cell unit 20a or It is possible to reduce the risk of cracking at 20b.

  Also in this embodiment, among the edge portions of the spacer 24 ′, the edge portions extending along the anodes AN ′, AN ′,... Or the gas flow paths GRf ′, GRf ′,. It extends in the X-axis direction at a position overlapping with the SP 42 '(that is, a position avoiding the gas flow path GRf'). Further, among the edge portions of the spacer 24 ′, the edge portions extending along the cathodes CT ′ and CT ′ or the gas flow paths GRa ′, GRa ′,... Overlap with the partial separator SP22 ′ as viewed from the Z-axis direction It extends in the Y-axis direction at a position avoiding the gas flow path GRa '.

  Therefore, as in the first embodiment, due to the difference in thermal expansion coefficient between the separators SP1 'to SP5' forming the fuel cells 20a 'and 20b' and the metal plate 22 'or the conductive material 26'. It is possible to reduce the concern that the gas flow paths GRf ′, GRf ′,... Or the gas flow paths GRa ′, GRa ′,.

  It is needless to say that the configurations of the plurality of embodiments described above can be combined appropriately as long as no contradiction arises.

10, 10 '... Fuel cell unit 12, 12' ... Fuel cell stack 122, 122 '... Air electrode layer 123, 123' ... Solid electrolyte layer 124, 124 '... Fuel electrode layer AN, AN' ... Fuel electrode CT, CT '... Air pole SP1 to SP5, SP1' to SP5 '... Separators GRf, GRf' ... Gas flow path (first gas flow path)
GRa, GRa '... gas flow path (second gas flow path)
VHf, VHa, VHf ', VHa' ... via conductors (conductors)
18a, 18b, 24, 18a ', 18b', 24 '... Spacers 20a, 20b, 20a', 20b '... Fuel cells 24f 1, 24f 2, 24a 1, 24a 2 ... Small spacers 22, 22' ... Metal plates 26, 26 ' ... Conductive material 28, 28 '... Adhesives EGf1, EGf2 ... Edge part (first edge part)
EGa1, EGa2 ... edge portion (second edge portion)
MFf1, MFf2, MFa1, MFa2, MFf1 ', MFf2', MFa1 ', MFa2' ... manifolds THf1, THf2, THa1, THa2, THf1 ', THf2', THa1 ', THa2' ... through holes

Claims (9)

A solid electrolyte layer, a fuel electrode layer and an air electrode layer stacked via the solid electrolyte layer, and a plurality of separators stacked on the fuel electrode layer and the air electrode layer, respectively, in the stacking direction In order to take out the current generated based on the fuel electrode gas and the air electrode gas, the gas flow path extending in the orthogonal direction and supplying the fuel electrode gas and the air electrode gas to the fuel electrode layer and the air electrode layer, respectively A solid oxide fuel cell unit having a plurality of fuel cells each formed with a conductor of
It is provided at a position between two fuel cells adjacent to each other in the stacking direction and at a partial position overlapping the conductor as viewed from the stacking direction, and is joined to each of the two fuel cells by a conductive material A metal plate, and a spacer provided at a position between the two fuel cells and at a position avoiding the metal plate as viewed from the stacking direction and joined to each of the two fuel cells;
At least one of the two fuel cells includes a first region overlapping with the metal plate when viewed from the stacking direction, and a second region overlapping with the spacer when viewed from the stacking direction, The fuel cell unit, wherein the rigidity of the two regions exceeds the rigidity of the first region.   The fuel cell unit according to claim 1, wherein an edge portion of the spacer extends along the gas flow path at a position avoiding the gas flow path as viewed from the stacking direction. The gas flow path includes a first gas flow path through which the fuel electrode gas flows and a second gas flow path through which the air electrode gas flows,
The fuel cell unit according to claim 2, wherein the edge portion includes a first edge portion extending along the first gas flow path and a second edge portion extending along the second gas flow path. Each of the plurality of fuel cells is further formed with a manifold that extends in the stacking direction and injects the fuel electrode gas and the air electrode gas into the gas flow path.
The fuel cell unit according to any one of claims 1 to 3, wherein a through hole communicating with the manifold is formed in the spacer. The plurality of fuel cells are deposited such that side surfaces orthogonal to the stacking direction are flush,
The fuel cell unit according to any one of claims 1 to 4, wherein the spacer has a tip projecting outward from the side surface as viewed from the stacking direction.   The fuel cell unit according to any one of claims 1 to 5, wherein the spacers include a plurality of small spacers separated from each other and formed in a stick shape.   Each of the plurality of small spacers has an end portion disposed at a position overlapping with the plurality of fuel cells as viewed from the stacking direction, and an outline of the end portion is curved as viewed from the stacking direction. The fuel cell unit according to Item 6. The spacer has an end disposed at a position overlapping the two fuel cells as viewed from the stacking direction.
The second region includes an end region overlapping with the end when viewed from the stacking direction, and a non-end region overlapping with a portion other than the end when viewing from the stacking direction,
The fuel cell unit according to any one of claims 1 to 4, wherein the rigidity of the end region is greater than the rigidity of the non-end region. Each of the fuel electrode layer and the air electrode layer is formed in the shape of a stick and formed of a plurality of poles arranged in parallel at equal intervals, and formed in the shape of a stick and the outermost of the plurality of poles. Including a partial separator located outside of the pole,
The fuel cell unit according to claim 8, wherein the gas flow channel is disposed between the plurality of poles, and the width of the partial separator is larger than the width of the gas flow channel.

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