JP2005158529A - Fuel battery cell, cell stack, and fuel battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery cell, a cell stack and a fuel battery of high output and high efficiency capable of preventing gas leak. <P>SOLUTION: A solid electrolyte 33 and electrodes 32, 34 are provided on one main face of a support board 31 having gas flow channels 31a, and an interconnector 35 on the other main face. Both end parts of the solid electrolyte 33 are extended from one main face to the other through side faces, and superposed on both end parts of the interconnector 35. The superposed parts A, B protrudes outward. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell, a cell stack, and a fuel cell, and in particular, a fuel cell having a solid electrolyte on one main surface of a support substrate having a gas flow path, an electrode, and an interconnector on the other main surface, and The present invention relates to a cell stack and a fuel cell.

  In recent years, various fuel cells in which a stack of fuel cells is accommodated in a storage container have been proposed as next-generation energy.

  Conventionally, a fuel cell constituting a cell stack has an interconnector formed on one side surface of an air electrode support that also serves as a support, and a solid electrolyte that is overlapped at both ends of the interconnector is provided with an air electrode support. In addition to the position where the interconnector is formed, a fuel electrode is formed on the surface of the solid electrolyte, and an overlapping portion between the end of the interconnector and the end of the solid electrolyte is formed on one side surface. (See Patent Document 1).

  In such a fuel cell, since both ends of the solid electrolyte overlap with both ends of the interconnector, the air in the air electrode support and the fuel gas outside the cell can be reliably sealed, and the solid electrolyte and the interconnect can be sealed. Air and fuel gas leakage can be suppressed from the interface with the connector.

The cell stack is configured by arranging the plurality of fuel cells at a predetermined interval, fuel gas is supplied between the stacks, and air is supplied to a gas flow path of an air electrode support of the fuel cell. Generate electricity.
JP-A 63-261678

  However, in conventional fuel cells, although fuel gas is supplied between the fuel cells, the amount of fuel gas supplied to the solid electrolyte via the fuel electrode is still low, and the use of fuel gas used for power generation is still low. There was a problem that the rate was low. For this reason, there existed a problem that the power generation performance of a fuel cell was still low.

  An object of the present invention is to provide a fuel cell, a cell stack, and a fuel cell that can prevent gas leakage and have high output and high efficiency.

  As a result of earnestly examining the above problems, the present inventor overlaps both ends of the solid electrolyte and both ends of the interconnector, and when the cell stack is configured by projecting these overlapping portions outward, When gas is supplied between one fuel battery cell and the other fuel battery cell, the gas can be forcibly supplied to the electrodes of the fuel cells arranged opposite to each other by the overlapping portion of the one fuel battery cell. The present inventors have found that the amount of gas supplied to can be improved, and have reached the present invention.

  That is, the fuel cell of the present invention is provided with a solid electrolyte on one side main surface of the support substrate having a gas flow path, an electrode, and an interconnector on the other side main surface, and both ends of the solid electrolyte from the one side main surface. It extends to the other side main surface through the side surface, overlaps with both end portions of the interconnector, and the end portions protrude outward.

  A plurality of such fuel cells are aligned at a predetermined interval so that the main surfaces face each other to form a cell stack.

  In such a fuel cell, since both ends of the solid electrolyte overlap with both ends of the interconnector, the inside and outside of the fuel cell can be reliably sealed by this dense solid electrolyte and interconnector, and the support substrate The gas that passes through the gas passage leaks to the outside of the cell, and the gas passing through the outside of the cell can be prevented from entering the inside of the cell.

  Moreover, in the conventional fuel cell, since both ends of the solid electrolyte and both ends of the interconnector are overlapped, the air in the air electrode support and the fuel gas outside the cell can be sealed, but the fuel electrode has the overlapping portion. Since the surface of the fuel electrode is substantially the same as the surface of the overlapping portion and there is no function of forced gas supply by the overlapping portion, the gas utilization rate is low. In the battery cell, the overlapping portion of the interconnector and the solid electrolyte protrudes outward, so that when the cell stack is configured, the gas supplied between the fuel cells is transferred to one of the fuel cells. A gas used for power generation can be supplied to the electrodes of the fuel cells arranged opposite to each other forcibly and disturbing the gas flow, and the amount of gas supplied to the solid electrolyte via the electrodes can be improved by the superimposing unit. Usage rate Enhanced, thereby improving the power generation performance of the fuel cell.

  The fuel cell according to the present invention is characterized in that the end portion of the solid electrolyte is laminated on the end portion of the interconnector. Further, the end of the interconnector is laminated on the end of the solid electrolyte. Furthermore, a P-type semiconductor is formed on the interconnector.

  In such a fuel cell, since the interconnector between the overlapping portions is concave, a P-type semiconductor can be easily formed in this portion by a technique such as screen printing. The P-type semiconductor is made of an air electrode material.

  The fuel cell of the present invention is characterized in that a cell stack is accommodated in a plurality of storage containers, and gas is supplied between the cell stacks. In such a fuel cell, as described above, gas leakage from the overlapping portion can be prevented, and a high-output and high-efficiency fuel cell can be provided. Therefore, a highly reliable fuel cell with excellent performance can be provided. .

  The fuel cell of the present invention can reliably seal the inside and outside of the fuel cell by the dense solid electrolyte and the interconnector, and the gas passing through the gas passage of the support substrate leaks to the outside of the cell, and the gas passing through the outside of the cell. Can be prevented from entering the inside of the cell, and when the cell stack is configured, the gas supplied toward the fuel cell is made to flow between the fuel cells arranged opposite to each other by the overlapping portion of one fuel cell. The gas flow can be forcibly and turbulently supplied to the electrode, the amount of gas supplied to the solid electrolyte via the electrode can be improved, the utilization rate of the gas used for power generation is increased, and the power generation performance of the fuel cell Can be improved.

  The fuel cell of the present invention will be described with reference to FIG. In FIG. 1, the fuel battery cell 30 has a plate shape and a column shape, and a support substrate 31 having a flat cross section is provided therein. A plurality of fuel gas passages 31 a are formed through the support substrate 31 at appropriate intervals, and the fuel cell 30 has a structure in which various members are provided on the support substrate 31. ing.

  That is, the fuel battery cell 30 is configured by forming the fuel electrode 32, the solid electrolyte 33, and the oxygen electrode 34 on one main surface of the support substrate 31, and forming the interconnector 35 on the other main surface. Both end portions of the solid electrolyte 33 are extended from one main surface to the other main surface via the side surfaces, and overlap with both end portions of the interconnector 35, respectively, and these overlapping portions A and B protrude outward. ing.

  Since both ends of the solid electrolyte 33 and both ends of the interconnector 35 are overlapped, the inside and outside of the cell can be effectively sealed, the fuel gas inside the cell leaks to the outside, and the oxygen-containing gas outside the cell It can be prevented from leaking inside.

  The overlapping portions A and B are configured by stacking the end portion of the interconnector 35 on the end portion of the solid electrolyte 33, and are formed in the fuel cell 30 in the axial direction and in parallel. The outer surface between the overlapping portions A and B is concave, and a P-type semiconductor 36 is formed on the concave surface located at the central portion between the overlapping portions A and B. The ends of the overlapping portions A and B can be chamfered by polishing or the like. In this case, the gas flow can be changed more smoothly by directing the oxygen-containing gas toward the opposing cell.

  A bonding layer 37 is formed between the support substrate 31 and the interconnector 35, and a diffusion preventing layer 38 is formed between the solid electrolyte 33 and the oxygen electrode 34.

  As shown in FIG. 1, the support substrate 31 includes a flat main surface and arc-shaped portions on both side surfaces. Both surfaces of the main surface are formed substantially parallel to each other, and the fuel electrode layer 32 is formed so as to cover one surface of the main surface and the arc-shaped portions on both sides, and further, this fuel electrode layer 32 is covered. A dense solid electrolyte 33 is laminated, and an oxygen electrode 34 is laminated on one surface of the main surface on the solid electrolyte layer 33 so as to face the fuel electrode layer 32. An interconnector 35 is formed on the other main surface where the fuel electrode layer 32 and the solid electrode layer 33 are not laminated. As is clear from FIG. 1, the fuel electrode 32 and the solid electrolyte 33 extend to both sides of the interconnector 35 and are configured so that the surface of the support substrate 31 is not exposed to the outside.

  In the fuel cell having the above structure, the portion of the fuel electrode 32 facing the oxygen electrode 34 operates as a fuel electrode to generate electric power. That is, an oxygen-containing gas such as air is flowed outside the oxygen electrode 34, and a fuel gas (hydrogen) is flowed into the gas passage 31a in the support substrate 31 and heated to a predetermined operating temperature. Electricity is generated by generating an electrode reaction of the following formula (1) and generating an electrode reaction of the following formula (2) in the portion of the fuel electrode 32 that becomes the fuel electrode.

Oxygen electrode: 1 / 2O ₂ + 2e ⁻ → O ²⁻ (solid electrolyte) (1)
Fuel electrode: O ²⁻ (solid electrolyte) + H ₂ → H ₂ O + 2e ⁻ (2)
The current generated by the power generation is collected through the interconnector 35 attached to the support substrate 31.

(Support substrate 31)
In the fuel cell 30 of the present invention having the above-described structure, the support substrate 31 is gas permeable to allow the fuel gas to permeate to the fuel electrode, and collects current through the interconnector 35. In order to satisfy such a requirement and at the same time avoid inconvenience caused by simultaneous firing, a Ni metal component and rare earth oxidation such as Y ₂ O ₃ and Yb ₂ O ₃ are required. The support substrate 31 is composed of the object.

  The Ni metal component is for imparting electrical conductivity to the support substrate 31, and may be a Ni metal alone, a Ni metal oxide, an alloy of Ni metal, or an alloy oxide. In the present invention, Ni and / or NiO are used because they are inexpensive and stable in fuel gas, but iron group metal components, iron group metal oxides, iron group metal alloys or alloy oxides are used. Any of these can be used.

The rare earth oxide component is used to approximate the thermal expansion coefficient of the support substrate 31 to the stabilized zirconia forming the solid electrolyte layer 33, and maintains a high conductivity and is a solid electrolyte layer. In order to prevent diffusion to 33 etc., Y ₂ O ₃ and Yb ₂ O ₃ are used because they are particularly inexpensive. If diffusion to the solid electrolyte layer 33 or the like can be prevented, at least one rare earth element selected from the group consisting of Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, Sm, and Pr Any oxide containing can be used.

  In the present invention, the iron group component described above is contained in the support substrate 31 in an amount of 35 to 65% by volume, particularly in that the thermal expansion coefficient of the support substrate 31 is approximated to stabilized zirconia. Is preferably contained in the support substrate 31 in an amount of 35 to 65% by volume.

  Since the support substrate 31 composed of the iron group metal component and the rare earth oxide as described above needs to have fuel gas permeability, the open porosity is usually 30% or more, particularly 35. It is preferable to be in the range of up to 50%. Further, the conductivity of the support substrate 31 is preferably 300 S / cm or more, and particularly preferably 440 S / cm or more.

(Fuel electrode layer 32)
In the present invention, the fuel electrode layer 32 causes the electrode reaction of the above-described formula (2), and is formed of a known porous conductive ceramic. For example, it is formed from ZrO ₂ in which a rare earth element is dissolved, and Ni and / or NiO. As ZrO ₂ (stabilized zirconia) in which the rare earth element is dissolved, the same one used for forming the solid electrolyte layer 33 described below is preferably used.

  The stabilized zirconia content in the fuel electrode layer 32 is preferably in the range of 35 to 65% by volume, and the Ni or NiO content is preferably in the range of 65 to 35% by volume. Further, the open porosity of the fuel electrode layer 32 is preferably 15% or more, particularly in the range of 20 to 40%, and the thickness is preferably 1 to 30 μm. For example, if the thickness of the fuel electrode layer 32 is too thin, the performance may be deteriorated, and if it is too thick, there is a risk of peeling due to a difference in thermal expansion between the solid electrolyte layer 33 and the fuel electrode layer 32. .

  Further, in the example of FIG. 1, the fuel electrode layer 32 extends to both sides of the interconnector 35, but it is sufficient that the fuel electrode is formed at a position facing the oxygen electrode 34. The fuel electrode 32 may be formed only on the main surface on the side where the oxygen electrode 34 is provided. Furthermore, the fuel electrode 32 can be formed over the entire circumference of the support substrate 31.

(Solid electrolyte layer 33)
The solid electrolyte 33 provided on the fuel electrode 32 is generally formed of a dense ceramic called ZrO ₂ (usually stabilized zirconia) in which 3 to 15 mol% of a rare earth element is dissolved. Examples of rare earth elements include Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, but they are inexpensive. From the viewpoint, Y, Yb, and Sc are desirable.

  The stabilized zirconia ceramics forming the solid electrolyte layer 33 is desirably a dense material having a relative density (according to Archimedes method) of 93% or more, particularly 95% or more from the viewpoint of preventing gas permeation. It is desirable that the thickness is 10 to 100 μm.

(Oxygen electrode 34)
The oxygen electrode 34 is formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. As such a perovskite oxide, at least one of transition metal perovskite oxides, particularly LaMnO ₃ oxides, LaFeO ₃ oxides, and LaCoO ₃ oxides having La at the A site is preferable. LaFeO ₃ -based oxides are particularly suitable because they have high electrical conductivity at an operating temperature of about 1000 ° C. In the perovskite oxide, Sr and the like may exist together with La at the A site, and Co and Mn may exist together with Fe at the B site.

Further, the oxygen electrode 34 must have gas permeability. Therefore, the conductive ceramic (perovskite oxide) forming the oxygen electrode 34 has an open porosity of 20% or more, particularly 30 to 50. It is desirable to be in the range of%.

  The thickness of the oxygen electrode 34 is preferably 30 to 100 μm from the viewpoint of current collection.

  The oxygen electrode 34 is formed only on one main surface of the support substrate 31, but may be formed up to an arcuate portion. Further, as long as the overlapping portions A and B protrude from the oxygen electrode 34, the oxygen electrode 34 may be formed up to the other main surface, but the current path in the support substrate 31 and the manufacturing viewpoint Therefore, it is desirable to form the oxygen electrode 34 only on the one side main surface.

(Interconnector 35)
The interconnector 35 provided on the support substrate 31 via the bonding layer 37 at the position facing the oxygen electrode 34 is made of conductive ceramics, but is in contact with the fuel gas (hydrogen) and the oxygen-containing gas. Therefore, it is necessary to have reduction resistance and oxidation resistance. For this reason, lanthanum chromite perovskite oxides (LaCrO ₃ oxides) are generally used as the conductive ceramics. Further, in order to prevent leakage of the fuel gas passing through the inside of the support substrate 31 and the oxygen-containing gas passing through the outside of the support substrate 31, such conductive ceramics must be dense, for example, 93% or more, particularly 95%. It is preferable to have the above relative density.

  The interconnector 35 is desirably 10 to 200 μm from the viewpoint of preventing gas leakage and electrical resistance. That is, if the thickness is smaller than this range, gas leakage is likely to occur, and if the thickness is larger than this range, the electric resistance is large, and the current collecting function may be reduced due to a potential drop. .

(P-type semiconductor 36)
A P-type semiconductor 36 is preferably provided on the outer surface (upper surface) of the interconnector 35. That is, in the cell stack assembled from the fuel cells (FIG. 2), a conductive current collecting member (not shown) is connected to the interconnector 35, but the current collecting member is directly connected to the interconnector 35. Then, the potential drop becomes large due to non-ohmic contact, and the current collecting performance is lowered.

  However, by connecting the current collecting member to the interconnector 35 via the P-type semiconductor 36, the contact between the two becomes an ohmic contact, the potential drop can be reduced, and the deterioration of the current collecting performance can be effectively avoided. Thus, for example, the current from the oxygen electrode 34 of one fuel cell 30 can be efficiently transmitted to the support substrate 31 of the other fuel cell 30. As such a P-type semiconductor, a transition metal perovskite oxide can be exemplified.

Specifically, those having higher electronic conductivity than LaCrO ₃ oxides constituting the interconnector 35, for example, LaMnO ₃ oxides and LaFeO ₃ oxides in which Mn, Fe, Co, etc. exist at the B site P-type semiconductor ceramics made of at least one of LaCoO ₃ -based oxides can be used. In general, the thickness of the P-type semiconductor 36 is preferably in the range of 30 to 100 μm. The P-type semiconductor is preferably formed from an oxygen electrode material.

(Junction layer 37)
The bonding layer 37 is a layer for bonding the support substrate 31 and the interconnector 35, and is made of Ni metal and / or an oxide of Ni metal and zirconia stabilized with rare earth. The stabilized zirconia content in the bonding layer 37 is 35. The Ni or NiO content is preferably in the range of 65 to 55% by volume. Since the thermal expansion coefficient of the joining layer 37 is made larger than the thermal expansion coefficient of the fuel electrode layer 32, the difference in thermal expansion between the interconnector 35 and the joining layer 37 can be reduced. This is because peeling of the interconnector 35 from the support substrate 31 can be suppressed.

(Diffusion prevention layer 38)
A diffusion preventing layer 38 is provided between the solid electrolyte 33 and the oxygen electrode 34. The diffusion prevention layer 38 is a composite oxide made of CeO ₂ in which Sm represented by the general formula of (CeO ₂ ) _1-x (SmO _1.5 ) _x (0 <x ≦ 0.3) is dissolved. Is preferred. In particular, from the viewpoint of reducing electrical resistance, x in the general formula is preferably made of CeO ₂ in which Sm ₂ O ₃ having a composition represented by 0.1 ≦ x ≦ 0.2 is dissolved. Further, in order to increase the effect of blocking or suppressing the diffusion, another rare earth element oxide may be contained.

Moreover, it is preferable that the diffusion prevention layer 38 adjusts the aggregation degree of CeO ₂ in which Sm ₂ O ₃ is dissolved to 5 to 35. Thereby, baking shrinkage can be controlled and peeling and crack generation of the solid electrolyte 33 can be prevented. In particular, it is desirable to adjust the aggregation degree to 5 to 15 in that the power generation performance can be prevented from being lowered.

(Manufacture of fuel cells)
The fuel battery cell having the above structure is manufactured as follows. First, a rare earth element oxide powder excluding La, Ce, Pr, and Nd elements and Ni and / or NiO powder are mixed, and a support substrate material in which an organic binder and a solvent are mixed is extruded into the mixed powder. To produce a support substrate molded body.

Next, Ni and / or NiO powder, ZrO ₂ powder in which a rare earth element is dissolved, an organic binder, and a solvent are mixed to produce a slurry that becomes a fuel-side electrode molded body.

  Next, the slurry used as a fuel side electrode is apply | coated to the thickness of 2-10 micrometers using the mesh platemaking on the one side main surface of the said support substrate molded object, and it dries at the temperature of 80-150 degreeC.

Next, a sheet-like solid electrolyte molded body is prepared using a solid electrolyte material in which a rare earth element is solid-solved ZrO ₂ powder, an organic binder, and a solvent. Next, a slurry to be the fuel side electrode is applied to one side of the solid electrolyte molded body, and the solid electrolyte molded body is applied to the coating film to be the fuel side electrode formed on the one main surface of the support substrate molded body. Wrapped so that the coating film serving as the fuel-side electrode contacts and the both end surfaces of the solid electrolyte molded body are spaced apart from each other at a predetermined interval on the other main surface, and dried at a temperature of 80 to 150 ° C. To do.

  Next, a sheet-like interconnector molded body is prepared using an interconnector material in which a lanthanum-chromium oxide powder, an organic binder, and a solvent are mixed.

Next, a slurry to be an intermediate film molded body in which Ni and / or NiO powder, ZrO ₂ powder in which a rare earth element is dissolved, an organic binder, and a solvent is mixed is prepared and applied to one side of the interconnector molded body .

  Next, the surface on which the slurry is applied to the sheet-like interconnector molded body is in contact with the exposed support substrate molded body, and both ends of the interconnector molded body abut both ends of the solid electrolyte molded body. Laminate to touch.

  As a result, the fuel-side electrode molded body and the solid electrolyte molded body are sequentially laminated on one side main surface of the support substrate molded body, and the intermediate film molded body and the interconnector molded body are laminated on the other main surface. A laminated molded body is produced in which both ends of the molded body are laminated on both ends of the solid electrolyte molded body. In addition, each molded object can be produced by sheet | seat shaping | molding by a doctor blade, printing, slurry dip, spraying by spraying, etc., or may be produced by a combination thereof.

  Next, the multilayer molded body is degreased and cofired at 1300 to 1600 ° C. in an oxygen-containing atmosphere.

  Next, a transition metal perovskite oxide powder, which is a P-type semiconductor, and a solvent are mixed to prepare a paste. The laminate is immersed in the paste, and oxygen is deposited on the surfaces of the solid electrolyte 33 and the interconnector 35. The fuel cell 30 of the present invention can be produced by forming the side electrode molded body and the P-type semiconductor molded body by dipping, screen printing, direct spray coating, and baking at 1000 to 1300 ° C. Since the overlapping part of both ends of the interconnector and both ends of the solid electrolyte protrudes to the outside and a recess is formed between them, it can be easily formed by dipping and screen printing in the recess.

  In addition, since the Ni component in the support substrate 31, the fuel side electrode 32, and the bonding layer 37 is NiO in the fuel cell 30 by firing in an oxygen-containing atmosphere, after that, the reducing property is reduced from the support substrate 31 side. Then, NiO is reduced at 800 to 1000 ° C. Further, this reduction process may be performed during power generation.

  As shown in FIG. 2, the cell stack has a plurality of fuel cells 30 arranged at predetermined intervals so that their main surfaces face each other, and one fuel cell 30 and the other fuel cell 30. A current collecting member (not shown) made of a metal felt and / or a metal plate is interposed between the support substrate 31 of one fuel cell 30 and a bonding layer 37 provided on the support substrate 31. It is configured to be electrically connected in series to the oxygen side electrode 34 of the other fuel cell 30 through the interconnector 35, the P-type semiconductor 36, and the current collecting member.

  The current collecting member is preferably made of at least one of Pt, Ag, Ni-base alloy, and Fe—Cr steel alloy from the viewpoint of heat resistance, oxidation resistance, and electrical conductivity.

  The fuel cell of the present invention is configured by arranging and storing a plurality of the cell stacks of FIG. 2 in a storage container, and an oxygen-containing gas supply pipe 22 is provided between the plurality of cell stacks. The storage container is provided with an introduction pipe for introducing a fuel gas such as hydrogen and an oxygen-containing gas such as air into the fuel battery cell 30 from the outside. The fuel container 30 is heated to a predetermined temperature to generate power. The used fuel gas and oxygen-containing gas are mixed and burned, and discharged out of the storage container.

  FIG. 3 shows another embodiment of the present invention. In this embodiment, the end portion of the solid electrolyte 33 is laminated on the end portion of the interconnector 35, and the overlapping portions A and B protruding outside are formed. Yes. Even in such a fuel cell, the overlapping portions A and B protrude to the outside, and a recess is formed between them. Therefore, the same effect as the fuel battery cell shown in FIG. 1 can be obtained. Further, the case of FIG. 3 is more desirable because the oxygen-containing gas from between the cell stacks can be smoothly supplied to the oxygen electrodes of the cells facing each other by the overlapping portions A and B.

  In addition, this invention is not limited to the said form, A various change is possible in the range which does not change the summary of invention. For example, the inner electrode may be formed from an oxygen electrode.

Further, the support substrate and the inner electrode may be formed with the same composition. For example, ZrO _{2 in} which Ni and Y ₂ O ₃ are dissolved may be used. In this case, the support substrate and the inner electrode are replaced with an inner electrode that also serves as a support.

The fuel cell of this invention is shown, (a) is sectional drawing, (b) is a cross-sectional perspective view. Explanatory drawing which shows a cell stack. The other fuel cell of this invention is shown, (a) is sectional drawing, (b) is a cross-sectional perspective view.

Explanation of symbols

22 ... Oxygen-containing gas supply pipe 30 ... Fuel cell 31 ... Support substrate 31a ... Gas flow path 32 ... Fuel side electrode 33 ... Solid electrolyte 34 ... Oxygen electrode 35 ..Interconnector 36 ... P-type semiconductor A, B ... overlapping part

Claims (7)

A support substrate having a gas flow path is provided with a solid electrolyte and electrodes on one main surface of the support substrate, and an interconnector on the other main surface, and both ends of the solid electrolyte extend from the one main surface to the other main surface through the side surfaces. A fuel cell, wherein the fuel cell overlaps with both end portions of the interconnector, and the overlapping portion protrudes outward. 2. The fuel cell according to claim 1, wherein an end of the solid electrolyte is laminated on the end of the interconnector. 2. The fuel cell according to claim 1, wherein the end of the interconnector is laminated on the end of the solid electrolyte. The fuel cell according to any one of claims 1 to 3, wherein a P-type semiconductor is formed on the interconnector. The fuel cell according to claim 4, wherein the P-type semiconductor is made of an air electrode material. 6. A cell stack, wherein the fuel cells according to any one of claims 1 to 5 are aligned at a predetermined interval so that main surfaces thereof are opposed to each other. A fuel cell, wherein the cell stack according to claim 6 is accommodated in a plurality of storage containers, and gas is supplied between the cell stacks.

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