JP6110324B2 - Fuel cell unit - Google Patents

Description

  The present invention relates to a fuel cell unit, and more particularly to a fuel cell unit that generates electric power based on gas taken in through a first air supply hole and a second air supply hole provided in a first member and a second member, respectively. .

  In this type of fuel cell unit, the fuel cell stack has a hydrogen gas manifold and an air manifold, and the holder for holding the fuel cell stack has a hydrogen gas supply hole and an air supply hole. The hydrogen gas manifold and the air manifold are opened on the lower surface of the fuel cell stack, and the hydrogen gas supply hole and the air supply hole are opened on the upper surface of the holder. The fuel cell stack is placed on the holder such that the hydrogen gas manifold and the air manifold communicate with the hydrogen gas supply hole and the air supply hole, respectively.

  The hydrogen gas is supplied to the fuel electrode of the fuel cell stack through the hydrogen gas supply hole and the hydrogen gas manifold. On the other hand, the air is supplied to the air electrode through the air supply hole and the air manifold. Electric power is generated by causing a chemical reaction between the hydrogen gas and air thus supplied.

  Here, since hydrogen gas or air may leak from between the holder and the fuel cell stack, a gas seal material is usually filled between the lower surface of the fuel cell stack and the upper surface of the holder.

  However, when the coefficient of thermal expansion differs between the holder and the fuel cell stack, if the lower surface of the fuel cell stack and the upper surface of the holder are formed flat, the gas seal material is easily peeled off due to the stress caused by the difference in the coefficient of thermal expansion. This causes a problem that gas leaks to the outside of the fuel cell unit.

JP-A-2005-339906

  In Patent Document 1 relating to a gas shutoff technique comprising a fuel cell, a cell support plate, a manifold, and a gas seal material, the end of the fuel cell is inserted into a slit provided in the cell support plate, and the inserted end A gas seal material is allowed to flow around the fuel cell to provide a gas seal between the fuel cell and the cell support plate. In addition, a cell support plate is fitted into a manifold having an opening on the entire top surface, and a gas seal is filled between the manifold and the cell support plate to provide a gas seal between the cell support plate and the manifold. ing.

  However, in Patent Document 1, since the seal area depends on the shape of the fuel cell, the seal area cannot be reduced. In addition, if the seal area is large, the thermal stress on the fuel cell increases and the fuel cell may be destroyed. Further, in Patent Document 1, since the fuel cell and the cell support plate are directly gas-sealed, the fuel cell is destroyed by the thermal stress from the cell support plate. Further, when the weight of the fuel cell is large, the cell support plate is destroyed.

  Therefore, a main object of the present invention is to provide a fuel cell unit that can prevent gas leakage from between two members having different coefficients of thermal expansion.

The fuel cell unit of this invention, the holder comprising a first member and having a first thermal expansion coefficient the first major surface is formed as a top surface, a second major surface that is in contact and the first main surface and the surface A fuel cell stack with an adapter made of a second member formed as a lower surface; a first air supply hole provided in the first member; a second air supply hole provided in the second member and communicating with the first air supply hole; a fuel cell unit for generating electric power based on the gas taken in through the adapter as a main component a ceramic, a second thermal expansion coefficient lower than the first thermal expansion coefficient and chromatic, the holder and the fuel cell stack The first member has a concave portion formed on the first main surface, the second member has a convex portion formed on the second main surface and fitted with the concave portion, and the first air supply hole And the second air supply holes open to the bottom surface of the concave portion and the top surface of the convex portion, respectively. Further example Bei the filled sealing material between the inner and outer circumferential surfaces of the convex portion of the parts, the fuel cell unit regardless of any on whether the operation state and stop state, from between the concave and convex portions Ru can be prevented leakage of air or hydrogen gas.

Preferably, the gas comprises aerobic gas and hydrogen gas, wherein the first air supply hole aerobic gas and the first hydrogen gas supply hole and a contact first aerobic gas supply holes respectively supply hydrogen gas, a second sheet pores includes a first aerobic gas supply holes and the first hydrogen gas supply hole and a second aerobic gas supply holes Contact and second hydrogen gas supply holes respectively communicating.

  Preferably, the sealing material includes a glass material.

  In one aspect, the glass material is one of crystallized glass and amorphous glass.

  In another aspect, the sealing material further includes a filler.

  The first member is provided with a recess having a bottom surface in which the opening of the first air supply hole is formed. Further, the second member is provided with a convex portion having a top surface in which the opening of the second air supply hole is formed and fitting with the concave portion. Furthermore, the thermal expansion coefficient of the second member is lower than that of the first member, and the sealing member is filled between the inner peripheral surface of the concave portion and the outer peripheral surface of the convex portion.

  Due to the difference in thermal expansion coefficient, the amount by which the inner peripheral surface of the recess moves inward when the temperature decreases is larger than the amount by which the outer peripheral surface of the protrusion moves inward when the temperature decreases. The pressure applied to the seal member sandwiched between the inner peripheral surface of the concave portion and the outer peripheral surface of the convex portion increases as the temperature decreases.

  Therefore, by determining the sizes of the recesses and the projections based on the gas seal formation (at the time of high temperature), regardless of whether the fuel cell unit is in the operating state or the stopped state, Leakage of air or hydrogen gas can be reliably prevented.

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

It is a perspective view which shows the external appearance of the fuel cell unit of this Example. It is an illustration figure which shows the state which decomposed | disassembled the fuel cell unit shown in FIG. (A) is a top view which shows the state which looked at the holder which comprises a fuel cell unit from the top, (B) is sectional drawing which shows a certain cross section of the holder which comprises a fuel cell unit, (C) It is sectional drawing which shows the other cross section of the holder which comprises a fuel cell unit. (A) is a perspective view showing a state in which a plate material constituting the fuel cell unit is viewed from obliquely above, and (B) is a perspective view showing a state in which the plate material constituting the fuel cell unit is viewed obliquely from below. It is an illustration figure which shows the positional relationship of the holder which comprises a fuel cell unit, a board | plate material, and a gas seal material. (A) is an illustrative view showing a positional relationship between a holder, a plate material, and a gas seal material when the fuel cell unit is operating, and (B) is a holder, a plate material, and a gas when the fuel cell unit is stopped. It is an illustration figure which shows the positional relationship of a sealing material, (C) is an enlarged view which shows the positional relationship of the convex part formed in the board | plate material, and the recessed part formed in the holder. It is an illustration figure which shows a part of state which decomposed | disassembled the fuel cell unit of the other Example. (A) is a perspective view showing a state in which a plate material constituting the fuel cell unit is viewed from obliquely above, and (B) is a perspective view showing a state in which the plate material constituting the fuel cell unit is viewed obliquely from below. It is a perspective view which shows the external appearance of the fuel cell unit of the other Example. FIG. 10 is an illustrative view showing a state in which the fuel cell unit shown in FIG. 9 is disassembled. (A) is a plan view showing a holder constituting the fuel cell unit, (B) is a cross-sectional view showing a certain section of the holder constituting the fuel cell unit, and (C) constitutes the fuel cell unit. It is sectional drawing which shows the other cross section of a holder. (A) is a perspective view showing a state in which a plate material constituting the fuel cell unit is viewed from obliquely above, and (B) is a perspective view showing a state in which the plate material constituting the fuel cell unit is viewed obliquely from below. It is an illustration figure which shows a part of state which decomposed | disassembled the fuel cell unit of other Example. (A) is a perspective view showing a state in which a plate material constituting the fuel cell unit is viewed from obliquely above, and (B) is a perspective view showing a state in which the plate material constituting the fuel cell unit is viewed obliquely from below. It is an illustration figure which shows a part of state which decomposed | disassembled the fuel cell unit of the other Example. (A) is a perspective view showing a state in which a plate material constituting the fuel cell unit is viewed from obliquely above, and (B) is a perspective view showing a state in which the plate material constituting the fuel cell unit is viewed obliquely from below. It is a perspective view which shows the external appearance of the fuel cell unit of the other Example. It is an illustration figure which shows the state which decomposed | disassembled the fuel cell unit shown in FIG. (A) is a top view which shows the holder which comprises a fuel cell unit, (B) is sectional drawing which shows a certain cross section of the holder which comprises a fuel cell unit. (A) is a front view which shows the state seen from the front which shows a fuel cell, (B) is a bottom view which shows the state which looked at the fuel cell from the bottom. Furthermore, it is an illustration figure which shows the state which decomposed | disassembled the fuel cell unit of the other Example. It is an illustration figure which shows the structure of the holder which comprises the fuel cell unit of another Example. It is an illustration figure which shows the structure of the fuel cell which comprises the fuel cell unit of another Example.

  1 and 2, a fuel cell unit 10 of this embodiment is a solid oxide type (SOFC type) fuel cell unit, and has a cubic fuel cell stack 12 and a plate-like shape for holding it. Holder 16a. Further, a plate member 14a that functions as an adapter is inserted between the fuel cell stack 12 and the holder 16a. 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 fuel cell unit 10. Although omitted in the drawing, the fuel cell stack 12 is provided with electrodes (the same applies to other embodiments).

  The size of the main surface of the plate material 14a (= surface orthogonal to the Z axis) matches the size of the main surface of the fuel cell stack 12 (= surface orthogonal to the Z axis), and the side surface (= X axis and Y axis) of the plate material 14a. Of the fuel cell stack 12 so that the side surfaces of the fuel cell stack 12 are flush with the side surface of the fuel cell stack 12 (= the surface perpendicular to each of the X and Y axes). It is attached to the side facing side. Further, the size of the main surface of the holder 16a (= the surface orthogonal to the Z axis) is larger than the sizes of the main surfaces of the fuel cell stack 12 and the plate material 14a, and the plate material 14a is provided at the center of the main surface of the holder 16a.

  With reference to FIGS. 2 and 3A to 3C, recesses CC1a and CC2a are formed on the upper surface of the holder 16a (= the surface facing the positive side in the Z-axis direction). The concave portion CC1a extends along the X axis at the positive side position in the Y axis direction from the center of the upper surface, and the concave portion CC2a extends along the Y axis at the negative side in the X axis direction from the center of the upper surface. The holder 16a is also provided with an air supply hole HL1a for supplying air taken from the outside to the fuel cell stack 12, and an air supply hole HL2a for supplying hydrogen gas taken from the outside to the fuel cell stack 12. . One end of air supply hole HL1a opens at the bottom surface of recess CC1a, and one end of air supply hole HL2a opens at the bottom surface of recess CC2a.

  With reference to FIGS. 2 and 4A to 4B, convex portions CV1a and CV2a are formed on the lower surface (= the surface facing the negative side in the Z-axis direction) of the plate member 14a. The convex portion CV1a extends along the X axis at the positive side position in the Y axis direction from the center of the lower surface, and the convex portion CV2a extends along the Y axis at the negative side position in the X axis direction from the center of the lower surface. The plate member 14a is also provided with through holes PH1a and PH2a that reach the lower surface from the upper surface (= the surface facing the positive side in the Z-axis direction).

  One end of each of the through holes PH1a and PH2a is opened at the upper surface of the plate member 14a, the other end of the through hole PH1a is opened at the top surface of the convex portion CV1a, and the other end of the through hole PH2a is at the top surface of the convex portion CV2a. Open.

  The width and length of the recess CC1a match the width and length of the recess CC2a, and the width and length of the protrusion CV1a also match the width and length of the protrusion CV2a. Further, the depth of the concave portion CC1a matches the height of the convex portion CV1a, and the depth of the concave portion CC2a matches the height of the convex portion CV2a. Furthermore, the size of the opening at one end of the air supply hole HL1a matches the size of the opening at the other end of the through hole PH1a, and the size of the opening at the one end of the air supply hole HL2a is the size of the opening at the other end of the through hole PH2a. Match.

  Further, an intersection of a straight line extending in the length direction of the center of the recess CC1a and a straight line extending in the length direction of the center of the recess CC2a is defined as a “first intersection”, and the width direction of the protrusion CV1a When the intersection of the straight line extending in the length direction at the center and the straight line extending in the length direction at the center in the width direction of the convex portion CV2a is defined as the “second intersection point”, the one end of the air supply hole HL1a from the first intersection point The distance to the opening coincides with the distance from the second intersection to the other end of the through hole PH1a, and the distance from the first intersection to the opening at one end of the air supply hole HL2a is the opening at the other end of the through hole PH2a from the second intersection. Matches the distance to.

  However, the width and length of the concave portion CC1a are slightly larger than the width and length of the convex portion CV1a, and the width and length of the concave portion CC2a are slightly larger than the width and length of the convex portion CV2a. Therefore, when the plate member 14a is placed on the holder 16a so that the convex portions CV1a and CV2a are fitted to the concave portions CC1a and CC2a, the air supply holes HL1a and HL2a communicate with the through holes PH1a and PH2a, respectively, and the outer periphery of the convex portion CV1a. A slight gap is formed between the surface and the inner peripheral surface of the recess CC1a.

  Referring to FIGS. 2 and 5, the gap between the outer peripheral surface of convex portion CV1a and the inner peripheral surface of concave portion CC1a is filled with gas seal material 181a. Further, a gas seal material 182a is filled in a gap between the outer peripheral surface of the convex portion CV2a and the inner peripheral surface of the concave portion CC2a. Air supplied through the air supply hole HL1a propagates upward through the through hole PH1a, and hydrogen gas supplied through the air supply hole HL2a propagates upward through the through hole PH2a. From between the holder 16a and the plate member 14a, The leakage of air or hydrogen gas is prevented by the gas sealing materials 181a and 182a thus filled.

  As shown in FIG. 2, the fuel cell stack 12 includes a plurality of fuel cells 12cl, 12cl,... Stacked in the Z-axis direction and an end plate 12ep stacked on the uppermost fuel cell 12cl. The

  Each of the plurality of fuel cells 12cl, 12cl,... Is formed with an air manifold MF1 and a hydrogen gas manifold MF2. The positions and sizes of the manifolds MF1 and MF2 are common among the plurality of fuel cells 12cl, 12cl,. Therefore, when viewed from the Z-axis direction, the plurality of manifolds MF1, MF1,... Communicate with each other, and the plurality of manifolds MF2, MF2,.

  When viewed from the Z-axis direction, the position where the manifold MF1 is formed coincides with the position where the through hole PH1a is formed, and the position where the manifold MF2 is formed coincides with the position where the through hole PH2a is formed. Therefore, the air supply hole HL1a communicates with the manifold MF1 through the through hole PH1a, and the air supply hole HL2a communicates with the manifold MF2 through the through hole PH2a.

Air is supplied to the air electrode through the air supply hole HL1a, the through hole PH1a, and the manifold MF1. Further, the hydrogen gas is supplied to the fuel electrode through the air supply hole HL2a, the through hole PH2a, and the manifold MF2. The supplied air and hydrogen gas undergo chemical reactions according to Chemical Formulas 1 and 2. As a result, a positive voltage and a negative voltage are generated from the fuel cell stack 12. The operating temperature of the fuel cell stack 12 is 600 ° C. to 850 ° C.
[Chemical 1]
1 / 2O ₂ + 2e ⁻ → O ²⁻
[Chemical formula 2]
H ₂ + O ²⁻ → H ₂ O + 2e ⁻

The fuel cell stack 12 and the plate material 14a have ceramic (for example, 3YSZ) as a main component, while the holder 16a has a metal (for example, a ferrite alloy) as a main component. Therefore, the thermal expansion coefficient of the holder 16a is larger than the thermal expansion coefficient of each of the fuel cell stack 12 and the plate material 14a. Specifically, the thermal expansion coefficient of the former exceeds the thermal expansion coefficient of the latter in the range of less than 1 × 10 ⁻⁶ / ° C.

  The gas sealants 181a and 182a are mainly composed of crystallized glass and soften at around 700 ° C. The softened gas seal material 181a is in close contact with the outer peripheral surface of the convex portion CV1a and the inner peripheral surface of the concave portion CC1a, and the softened gas seal material 182a is in close contact with the outer peripheral surface of the convex portion CV2a and the inner peripheral surface of the concave portion CC2a. Further, the softened gas sealing materials 181a and 182a are crystallized at 900 ° C.

  Referring to FIGS. 6A to 6C, the size of the gap between the outer peripheral surface of convex portion CV1a and the inner peripheral surface of concave portion CC1a is substantially the same at the crystallization temperature of gas seal material 181a. It will be adjusted. Similarly, the size of the gap between the outer peripheral surface of the convex portion CV2a and the inner peripheral surface of the concave portion CC2a is adjusted to a size that substantially matches the crystallization temperature of the gas seal material 182a.

  When the fuel cell stack 12 is lowered to room temperature after crystallization of the gas seal materials 181a and 182a, due to the difference between the thermal expansion coefficient of the plate material 14a and the thermal expansion coefficient of the holder 16a, the outer peripheral surface of the convex portion CV1a and the concave portion CC1a And the gap between the outer peripheral surface of the convex portion CV2a and the inner peripheral surface of the concave portion CC2a are narrowed. That is, the holder 16a shrinks more greatly than the plate material 14a, and the inner peripheral surface of the concave portion CC1a and the inner peripheral surface of the concave portion CC2a approach the outer peripheral surface of the convex portion CV1a and the outer peripheral surface of the convex portion CV2a, respectively. The gas sealing material 181a is subjected to compressive stress by the outer peripheral surface of the convex portion CV1a and the inner peripheral surface of the concave portion CC1a, and the gas sealing material 182a is subjected to compressive stress by the outer peripheral surface of the convex portion CV2a and the inner peripheral surface of the concave portion CC2a. It takes. Further, even under the operating temperature of the fuel cell stack 12, the gas sealing material 181a has an outer peripheral surface of the convex portion CV1a and an inner peripheral surface of the concave portion CC1a because it is lower than the crystallization temperature of the gas sealing materials 181a and 182a. Thus, the compressive stress is continuously applied to the gas seal material 182a by the outer peripheral surface of the convex portion CV2a and the inner peripheral surface of the concave portion CC2a, and the gas seal is sealed at both room temperature and operating temperature. Performance is maintained.

  As can be seen from the above description, the holder 16a has air supply holes HL1a and HL2a, and the plate member 14a has through holes PH1a and PH2a. Moreover, the thermal expansion coefficient of the holder 16a is higher than the thermal expansion coefficient of the plate material 14a. The air taken in from the outside is supplied to the fuel cell stack 12 through the air supply hole HL1a and the through hole PH1a. Further, the hydrogen gas taken in from the outside is supplied to the fuel cell stack 12 through the air supply hole HL2a and the through hole PH2a. The fuel cell stack 12 generates electric power based on the air and hydrogen gas thus supplied.

  Here, the holder 16a has recesses CC1a and CC2a in which the openings of the air supply holes HL1a and HL2a are formed on the bottom surface. Further, the plate member 14a has convex portions CV1a and CV2a in which the openings of the through holes PH1a and PH2a are formed on the top surface and are fitted to the concave portions CC1a and CC2a. The gas sealing material 181a is filled between the inner peripheral surface of the concave portion CC1a and the outer peripheral surface of the convex portion CV1a, and the gas sealing material 182a is filled between the inner peripheral surface of the concave portion CC2a and the outer peripheral surface of the convex portion CV2a. .

  Due to the difference in coefficient of thermal expansion between the holder 16a and the plate material 14a, the amount of movement of the inner peripheral surfaces of the recesses CC1a and CC2a when the temperature decreases is the same as the amount of movement of the outer surfaces of the protrusions CV1a and CV2a when the temperature decreases. Larger than the amount to be. The pressure applied to the gas seal material 181a sandwiched between the inner peripheral surface of the concave portion CC1a and the outer peripheral surface of the convex portion CV1a increases as the temperature decreases, and is sandwiched between the inner peripheral surface of the concave portion CC2a and the outer peripheral surface of the convex portion CV2a. The pressure applied to the gas seal material 182a also increases as the temperature decreases.

  Therefore, by determining the sizes of the recesses CC1a and CC2a and the projections CV1a and CV2a with reference to the time when the gas seal is formed (at a high temperature), the holder can be used regardless of whether the fuel cell unit 10 is in the operating state or the stopped state. Leakage of air or hydrogen gas from between 16a and the plate member 14a can be reliably prevented. Moreover, since the recessed part CC2a and the convex part CV2a are formed in the position away from the recessed part CC1a and the convex part CV1a, mixing of air and hydrogen gas can be prevented.

  Referring to FIGS. 7 and 8A to 8B, in the fuel cell unit 10 of another embodiment, a plate material 14b is adopted instead of the plate material 14a, and a holder 16b is adopted instead of the holder 16a. The fuel cell unit 10 is the same as the fuel cell unit 10 shown in FIG. 1 except that gas seal materials 181b and 182b are employed instead of the gas seal materials 181a and 182a. For this reason, the overlapping description regarding the same structure is omitted as much as possible.

  On the upper surface of the holder 16b, recesses CC1b and CC2b whose cross section perpendicular to the Z axis forms a perfect circle are formed. The holder 16b is also provided with an air supply hole HL1b for supplying air taken from the outside to the fuel cell stack 12, and an air supply hole HL2b for supplying hydrogen gas taken from the outside to the fuel cell stack 12. .

  Here, the position and size of the opening at one end of the air supply hole HL1b coincide with the position and size of the opening at one end of the air supply hole HL1a shown in FIG. Similarly, the position and size of the opening at one end of the air supply hole HL2b coincide with the position and size of the opening at one end of the air supply hole HL2a shown in FIG. The position of the recess CC1b coincides with the position of the opening at one end of the air supply hole HL1b, and the size of the bottom surface of the recess CC1b exceeds the size of the opening at one end of the air supply hole HL1b. Similarly, the position of the recess CC2b coincides with the position of the opening at one end of the air supply hole HL2b, and the size of the bottom surface of the recess CC2b exceeds the size of the opening at one end of the air supply hole HL2b. Therefore, one end of air supply hole HL1b opens at the bottom surface of recess CC1b, and one end of air supply hole HL2b opens at the bottom surface of recess CC2b.

  Referring to FIGS. 8A to 8B, on the lower surface of the plate member 14b (= the surface facing the negative side in the Z-axis direction), a convex portion CV1b whose cross section perpendicular to the Z-axis forms a perfect circle and CV2b is formed. The plate member 14b is also formed with through holes PH1b and PH2b that reach the lower surface from the upper surface (= the surface facing the positive side in the Z-axis direction).

  The position and size of the through hole PH1b coincide with the position and size of the through hole PH1a shown in FIG. 2, and the position and size of the through hole PH2b coincide with the position and size of the through hole PH2a shown in FIG. Further, the position of the convex portion CV1b coincides with the position of the through hole PH1b, and the size of the top surface of the convex portion CV1b exceeds the size of the opening of the through hole PH1b. Similarly, the position of the convex portion CV2b coincides with the position of the through hole PH2b, and the size of the top surface of the convex portion CV2b exceeds the size of the opening of the through hole PH2b.

  Therefore, one end of each of the through holes PH1b and PH2b opens at the upper surface of the plate member 14b, and the other end of the through hole PH1b and the other end of the through hole PH2b are the top surface of the convex portion CV1b and the top surface of the convex portion CV2b, respectively. Open. The height of the convex portion CV1b matches the depth of the concave portion CC1b, and the height of the convex portion CV2b matches the depth of the concave portion CC2b.

  However, the diameter of the perfect circle forming the concave portion CC1b is slightly larger than the diameter of the perfect circle forming the convex portion CV1b, and the diameter of the perfect circle forming the concave portion CC2b is slightly larger than the diameter of the perfect circle forming the convex portion CV2b. Therefore, when the plate member 14b is placed on the holder 16b so that the convex portions CV1b and CV2b fit into the concave portions CC1b and CC2b, the air supply holes HL1b and HL2b communicate with the through holes PH1b and PH2b, respectively. A slight gap is formed between the outer peripheral surface of the convex portion CV1b and the inner peripheral surface of the concave portion CC1b, and a slight gap is also formed between the outer peripheral surface of the convex portion CV2b and the inner peripheral surface of the concave portion CC2b. .

  Gas seal material 181b is filled in the gap between the outer peripheral surface of the convex portion CV1b and the inner peripheral surface of the concave portion CC1b, and the gas seal material 182b is filled in the gap between the outer peripheral surface of the convex portion CV2b and the inner peripheral surface of the concave portion CC2b. Is done.

  The air taken in from the air supply hole HL1b is propagated upward through the through hole PH1b, and the hydrogen gas taken in from the air supply hole HL2b is propagated upward through the through hole PH2b, from between the holder 16b and the plate member 14b. The air leakage is avoided by the gas sealing material 181b, and the hydrogen gas leakage between the holder 16b and the plate material 14b is avoided by the gas sealing material 182b. Also in this embodiment, since the concave portion CC2b and the convex portion CV2b are formed at positions away from the concave portion CC1b and the convex portion CV1b, mixing of air and hydrogen gas can be prevented.

  Referring to FIGS. 9 and 10, the fuel cell unit 20 of another embodiment is also a solid oxide fuel cell unit, and includes a cubic fuel cell stack 22 and a plate-like holder 26a for holding the same. including. Further, a plate member 24a that functions as an adapter is inserted between the fuel cell stack 22 and the holder 26a. Also 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 fuel cell unit 20.

  The size of the main surface (= surface orthogonal to the Z axis) of the plate material 24a matches the size of the main surface (= surface orthogonal to the Z axis) of the fuel cell stack 22, and the side surface (= X axis and Y axis) of the plate material 24a. Of the fuel cell stack 22 so that the side surface of the fuel cell stack 22 is flush with the side surface of the fuel cell stack 22 (= the surface perpendicular to each of the X axis and the Y axis). It is attached to the side facing side. The size of the main surface of the holder 26a (= the surface orthogonal to the Z axis) is larger than the size of the main surfaces of the fuel cell stack 22 and the plate material 24a, and the plate material 24a is provided at the center of the main surface of the holder 26a.

  Referring to FIGS. 10 and 11A to 11C, the center position in the Y-axis direction is along the X-axis on the upper surface of the holder 26a (= the surface facing the positive side in the Z-axis direction). A recess CC11a extending along the Y-axis at a central position in the X-axis direction and on the negative side of the recess CC11a in the Y-axis direction, and a recess CC11a at the central position in the X-axis direction and in the Y-axis direction. A concave portion CC14a extending along the Y-axis at a position on the more positive side than that is formed. The holder 26a also has air supply holes HL11a and HL13a for supplying air taken from the outside to the fuel cell stack 22, and air supply holes HL12a and HL12a for supplying hydrogen gas taken from the outside to the fuel cell stack 22. HL14a is provided.

  One end of each of the air supply holes HL11a and HL13a opens at the bottom surface of the recess CC11a, one end of the air supply hole HL12a opens at the bottom surface of the recess CC12a, and one end of the air supply hole HL14a opens at the bottom surface of the recess CC14a. The opening at one end of the air supply hole HL11a is located on the positive side in the X-axis direction, and the opening at one end of the air supply hole HL13a is located on the negative side in the X-axis direction.

  Referring to FIGS. 10 and 12A to 12B, the central position in the Y-axis direction is along the X-axis on the lower surface of the plate 24a (= the surface facing the negative side in the Z-axis direction). A projecting part CV11a extending along the Y axis in the Y axis direction and a projecting part CV12a extending along the Y axis at a center position in the X axis direction and on the negative side of the projecting part CV11a in the Y axis direction , A convex portion CV14a extending along the Y axis at a position on the positive side of the convex portion CV11a is formed. The plate member 24a is also provided with through holes PH11a to PH14a that reach the lower surface from the upper surface (= the surface facing the positive side in the Z-axis direction).

  One end of each of the through holes PH11a to PH14a is opened at the upper surface of the plate member 24a, the other end of each of the through holes PH11a and PH13a is opened at the top surface of the convex portion CV11a, and the other end of the through hole PH12a is the convex portion CV12a. The other end of the through hole PH14a opens at the top surface of the convex portion CV14a. The other end of the through hole PH11a opens at a positive position in the X-axis direction, and the other end of the through hole PH13a opens at a negative position in the X-axis direction.

  The depth of the concave portion CC11a matches the height of the convex portion CV11a. The size of the opening at one end of the air supply hole HL11a matches the size of the opening at the other end of the through hole PH11a, and the size of the opening at one end of the air supply hole HL12a is the size of the opening at the other end of the through hole PH12a. The size of the opening at one end of the air supply hole HL13a matches the size of the opening at the other end of the through hole PH13a, and the size of the opening at the one end of the air supply hole HL14a is the opening at the other end of the through hole PH14a. Matches the size of.

  Further, the intersection of the straight line extending in the length direction of the center in the width direction of the recess CC11a and the straight line extending in the length direction of the centers of the widths of the recesses CC12a and CC14a is defined as a “third intersection”. When the intersection of the straight line extending in the length direction at the center in the width direction and the straight line extending in the length direction at the centers in the width direction of the convex portions CV12a and CV14a is defined as a “fourth intersection point”, the air supply hole HL11a from the third intersection point The distance from the first intersection to the opening of the through hole PH11a is the same as the distance from the fourth intersection to the other end of the through hole PH11a, and the distance from the third intersection to the opening of the one end of the air supply hole HL12a is from the fourth intersection to the through hole PH12a. It corresponds to the distance to the opening at the other end.

  Similarly, the distance from the third intersection to the opening at one end of the air supply hole HL13a coincides with the distance from the fourth intersection to the other end of the through hole PH13a, and from the third intersection to the opening at one end of the air supply hole HL14a. The distance coincides with the distance from the fourth intersection point to the opening at the other end of the through hole PH14a.

  However, the width and length of the concave portion CC11a are slightly larger than the width and length of the convex portion CV11a, the width and length of the concave portion CC12a are slightly larger than the width and length of the convex portion CV12a, and the width and length of the concave portion CC14a. The length is slightly larger than the width and length of the convex portion CV14a.

  Therefore, when the plate member 24a is placed on the holder 26a so that the convex portions CV11a, CV12a, and CV14a are fitted to the concave portions CC11a, CC12a, and CC14a, the air supply holes HL11a to HL14a communicate with the through holes PH11a to PH14a, respectively. A slight gap is formed between the outer peripheral surfaces of the parts CV11a, CV12a and CV14a and the inner peripheral surfaces of the recesses CC11a, CC12a and CC14a.

  Referring to FIG. 10, the gap between the outer peripheral surface of convex CV11a and the inner peripheral surface of concave portion CC11a is filled with gas seal material 281a, and the gap between the outer peripheral surface of convex portion CV12a and the inner peripheral surface of concave portion CC12a is filled. Is filled with a gas sealing material 282a, and a gap between the outer peripheral surface of the convex portion CV14a and the inner peripheral surface of the concave portion CC14a is filled with the gas sealing material 284a. The air supplied through the air supply holes HL11a and HL13a propagates upward through the through holes PH11a and PH13a, and the hydrogen gas supplied through the air supply holes HL12a and HL14a propagates upward through the through holes PH12a and PH14a. Leakage of air or hydrogen gas from between the plate 26a and the plate material 24a is prevented by the gas sealing materials 281a, 282a and 284a thus filled.

  Referring to FIG. 10, the fuel cell stack 22 includes a plurality of fuel cells 22cl, 22cl,... Stacked in the Z-axis direction, and an end plate 22ep stacked on the uppermost fuel cell 22cl. Composed.

  In each of the plurality of fuel cells 22cl, 22cl,..., Manifolds MF11 and MF13 for air and manifolds MF12 and MF14 for hydrogen gas are formed. The positions and sizes of the manifolds MF11 to MF14 are common among the plurality of fuel cells 22cl, 22cl,. Therefore, when viewed from the Z-axis direction, the plurality of manifolds MF11, MF11,... Communicate with each other, and the plurality of manifolds MF12, MF12,. Similarly, the plurality of manifolds MF13, MF13,... Communicate with each other, and the plurality of manifolds MF14, MF14,.

  Further, when viewed from the Z-axis direction, the position where the manifold MF11 is formed coincides with the position where the through hole PH11a is formed, the position where the manifold MF12 is formed coincides with the position where the through hole PH12a is formed, The position where the manifold MF13 is formed coincides with the position where the through hole PH13a is formed, and the position where the manifold MF14 is formed coincides with the position where the through hole PH14a is formed.

  Accordingly, the air supply hole HL11a communicates with the manifold MF11 through the through hole PH11a, the air supply hole HL12a communicates with the manifold MF12 through the through hole PH12a, and the air supply hole HL13a communicates with the manifold MF13 through the through hole PH13a. The air supply hole HL14a communicates with the manifold MF14 through the through hole PH14a.

  Air is supplied to the air electrode through the air supply hole HL11a, the through hole PH11a, and the manifold MF11, and is supplied to another air electrode through the air supply hole HL13a, the through hole PH13a, and the manifold MF13. The hydrogen gas is supplied to the fuel electrode through the air supply hole HL12a, the through hole PH12a and the manifold MF12, and is supplied to another fuel electrode through the air supply hole HL14a, the through hole PH14a and the manifold MF14.

  The supplied air and hydrogen gas undergo chemical reactions according to the above-described chemical formulas 1 and 2. As a result, a positive voltage and a negative voltage are generated from the fuel cell stack 22.

Also in this embodiment, the fuel cell stack 22 and the plate material 24a are mainly composed of ceramic (for example, 3YSZ), while the holder 26a is composed mainly of metal (for example, a ferrite alloy). Therefore, the thermal expansion coefficient of the holder 26a is larger than the thermal expansion coefficient of each of the fuel cell stack 22 and the plate member 24a. Specifically, the thermal expansion coefficient of the former exceeds the thermal expansion coefficient of the latter in the range of less than 1 × 10 ⁻⁶ / ° C.

  Further, the gas sealants 281a, 282a and 284a are mainly composed of crystallized glass and soften at around 700 ° C. The softened gas seal material 281a is in close contact with the outer peripheral surface of the convex portion CV11a and the inner peripheral surface of the concave portion CC11a, and the softened gas seal material 282a is in close contact with the outer peripheral surface of the convex portion CV12a and the inner peripheral surface of the concave portion CC12a. The gas seal material 284a is in close contact with the outer peripheral surface of the convex portion CV14a and the inner peripheral surface of the concave portion CC14a. Further, the softened gas sealing materials 281a, 282a and 284a are crystallized at 900 ° C.

  Also in this embodiment, due to the difference in the coefficient of thermal expansion between the holder 26a and the plate material 24a, the amount of movement of the inner peripheral surface of the recesses CC11a, CC12a and CC14a inward when the temperature decreases is the convex CV11a, The pressure applied to the gas sealants 281a, 282a and 284a is larger than the amount by which the outer peripheral surfaces of the CV 12a and CV 14a move inward, and increases as the temperature decreases.

  Accordingly, by determining the sizes of the concave portions CC11a, CC12a, CC14a and the convex portions CV11a, CV12a, CV14a with reference to the time when the gas seal is formed (at the time of high temperature), whether the fuel cell unit 20 is in the operating state or the stopped state Regardless, leakage of air or hydrogen gas from between the holder 26a and the plate member 24a can be reliably prevented.

  Referring to FIGS. 13 and 14A to 14B, the fuel cell unit 20 of still another embodiment employs a plate material 24b instead of the plate material 24a, and a holder 26b instead of the holder 26a. The fuel cell unit 20 is the same as the fuel cell unit 20 shown in FIG. 9 except that gas seal materials 2813b, 282b and 284b are used instead of the gas seal materials 281a, 282a and 284a. For this reason, the overlapping description regarding the same structure is omitted as much as possible.

  On the upper surface of the holder 26b, there are formed a recess CC113b whose cross section perpendicular to the Z axis forms a rectangle and extends in the X axis direction, and recesses CC12b and CC14b whose cross section perpendicular to the Z axis forms a perfect circle. The holder 26b also has air supply holes HL11b and HL13b for supplying air taken from outside to the fuel cell stack 22, and air supply holes HL12b and HL12b for supplying hydrogen gas taken from outside to the fuel cell stack 22. HL14b is provided.

  Here, the position and size of the opening at one end of the air supply hole HL11b coincide with the position and size of the opening at one end of the air supply hole HL11a shown in FIG. 10, and the position and size of the opening at one end of the air supply hole HL12b. Corresponds to the position and size of the opening at one end of the air supply hole HL12a shown in FIG. Further, the position and size of the opening at one end of the air supply hole HL13b coincide with the position and size of the opening at one end of the air supply hole HL13a shown in FIG. 10, and the position and size of the opening at one end of the air supply hole HL14b are as follows. This coincides with the position and size of the opening at one end of the air supply hole HL14a shown in FIG.

  Further, the width and length of the recess CC113b coincide with the width and length of the recess CC11a shown in FIG. The position of the recess CC12b coincides with the position of the opening at one end of the air supply hole HL12b, and the size of the bottom surface of the recess CC12b exceeds the size of the opening at one end of the air supply hole HL12b. The position of the recess CC14b coincides with the position of the opening at one end of the air supply hole HL14b, and the size of the bottom surface of the recess CC14b exceeds the size of the opening at one end of the air supply hole HL14b.

  Therefore, one end of each of supply holes HL11b and HL13b opens at the bottom surface of recess CC113b, one end of supply hole HL12b opens at the bottom surface of recess CC12b, and one end of supply hole HL14b opens at the bottom surface of recess CC14b. .

  Referring to FIGS. 14A to 14B, on the lower surface of the plate 24b (= the surface facing the negative side in the Z-axis direction), the cross section perpendicular to the Z-axis forms a rectangle in the X-axis direction. The extending convex portion CV113b and the convex portions CV12b and CV14b whose cross section perpendicular to the Z axis forms a perfect circle are formed.

  The plate member 24b is also formed with through holes PH11b to PH14b that reach the lower surface from the upper surface (= the surface facing the positive side in the Z-axis direction). The position and size of the through hole PH11b coincide with the position and size of the through hole PH11a shown in FIG. 10, and the position and size of the through hole PH12b coincide with the position and size of the through hole PH12a shown in FIG. Similarly, the position and size of the through hole PH13b match the position and size of the through hole PH13a shown in FIG. 10, and the position and size of the through hole PH14b match the position and size of the through hole PH14a shown in FIG. .

  Further, the position of the convex portion CV12b coincides with the position of the through hole PH12b, and the size of the top surface of the convex portion CV12b exceeds the size of the opening of the through hole PH12b. Similarly, the position of the convex portion CV14b coincides with the position of the through hole PH14b, and the size of the top surface of the convex portion CV14b exceeds the size of the opening of the through hole PH14b. On the other hand, the width and length of the convex portion CV113b coincide with the width and length of the convex portion CV11a shown in FIG.

  Therefore, one end of each of the through holes PH11b to PH14b opens at the upper surface of the plate member 24b, and the other end of the through hole PH12b and the other end of the through hole PH14b are the top surface of the convex portion CV12b and the top surface of the convex portion CV14b, respectively. Open. Further, the other end of the through hole PH11b and the other end of the through hole PH13b open at the top surface of the convex portion CV113b.

  Further, the height of the convex portion CV12b matches the depth of the concave portion CC12b, the height of the convex portion CV14b matches the depth of the concave portion CC14b, and the height of the convex portion CV113b matches the depth of the concave portion CC113b.

  However, the diameter of the perfect circle forming the concave portion CC12b is slightly larger than the diameter of the perfect circle forming the convex portion CV12b, and the diameter of the perfect circle forming the concave portion CC14b is slightly larger than the diameter of the perfect circle forming the convex portion CV14b. In addition, the width and length of the concave portion CC113b are slightly larger than the width and length of the convex portion CV113b.

  Therefore, when the plate member 24b is placed on the holder 26b so that the convex portions CV12b, CV14b, and CV113b fit into the concave portions CC12b, CC14b, and CC113b, the air supply holes HL11b to HL14b communicate with the through holes PH11b to PH14b, respectively. A slight gap is formed between the outer peripheral surface of the convex portion CV12b and the inner peripheral surface of the concave portion CC12b, and a slight gap is also formed between the outer peripheral surface of the convex portion CV14b and the inner peripheral surface of the concave portion CC14b. . Furthermore, a slight gap is also formed between the outer peripheral surface of the convex portion CV113b and the inner peripheral surface of the concave portion CC113b.

  The gap between the outer peripheral surface of the convex portion CV12b and the inner peripheral surface of the concave portion CC12b is filled with a gas seal material 282b, and the gap between the outer peripheral surface of the convex portion CV14b and the inner peripheral surface of the concave portion CC14b is filled with a gas seal material 284b. The gap between the outer peripheral surface of the convex portion CV113b and the inner peripheral surface of the concave portion CC113b is filled with a gas seal material 2813b.

  The air taken in from the air supply holes HL11b and HL13b is propagated upward through the through holes PH11b and PH13b, and the hydrogen gas taken in from the air supply holes HL12b and HL14b is propagated upward through the through holes PH12b and PH14b. Leakage of air from between the plate 26b and the plate member 24b is avoided by the gas sealant 2813b, and leakage of hydrogen gas from between the holder 26b and the plate member 24b is avoided by the gas sealants 282b and 284b. In this embodiment, the concave portion CC113b and the convex portion CV113b are formed at positions away from the concave portions CC12b and CC14b and the convex portions CV12b and CV14b, so that mixing of air and hydrogen gas can be prevented.

  Referring to FIGS. 15 and 16A to 16B, the fuel cell unit 20 of another embodiment employs a plate material 24c instead of the plate material 24a, and employs a holder 26c instead of the holder 26a. The fuel cell unit 20 is the same as the fuel cell unit 20 shown in FIG. 9 except that gas seal materials 281c to 284c are employed instead of the gas seal materials 281a, 282a and 284a. For this reason, the overlapping description regarding the same structure is omitted as much as possible.

  On the upper surface of the holder 26c, concave portions CC11c to CC14c whose cross section perpendicular to the Z axis forms a perfect circle are formed. The holder 26c also has air supply holes HL11c and HL13c for supplying air taken from outside to the fuel cell stack 22, and air supply holes HL12c for supplying hydrogen gas taken from outside to the fuel cell stack 22. HL14c is provided.

  Here, the position and size of the opening at one end of the air supply hole HL11c coincide with the position and size of the opening at one end of the air supply hole HL11a shown in FIG. 10, and the position and size of the opening at one end of the air supply hole HL12c. Corresponds to the position and size of the opening at one end of the air supply hole HL12a shown in FIG. Similarly, the position and size of the opening at one end of the air supply hole HL13c coincide with the position and size of the opening at one end of the air supply hole HL13a shown in FIG. 10, and the position and size of the opening at one end of the air supply hole HL14c. Corresponds to the position and size of the opening at one end of the air supply hole HL14a shown in FIG.

  The position of the recess CC11c matches the position of the opening at one end of the air supply hole HL11c, and the size of the bottom surface of the recess CC11c exceeds the size of the opening at one end of the air supply hole HL11c. The position of the recess CC12c coincides with the position of the opening at one end of the air supply hole HL12c, and the size of the bottom surface of the recess CC12c exceeds the size of the opening at one end of the air supply hole HL12c.

  The position of the recess CC13c matches the position of the opening at one end of the air supply hole HL13c, and the size of the bottom surface of the recess CC13c exceeds the size of the opening at one end of the air supply hole HL13c. The position of the recess CC14c matches the position of the opening at one end of the air supply hole HL14c, and the size of the bottom surface of the recess CC14c exceeds the size of the opening at one end of the air supply hole HL14c.

  Accordingly, one end of the air supply hole HL11c opens at the bottom surface of the recess CC11c, and one end of the air supply hole HL12c opens at the bottom surface of the recess CC12c. Further, one end of the air supply hole HL13c opens at the bottom surface of the recess CC13c, and one end of the air supply hole HL14c opens at the bottom surface of the recess CC14c.

  Referring to FIGS. 16A to 16B, on the lower surface of the plate 24c (= the surface facing the negative side in the Z-axis direction), a convex portion CV11c whose cross section perpendicular to the Z-axis forms a perfect circle is provided. CV14c is formed. The plate member 24c is also formed with through holes PH11c to PH14c that reach the lower surface from the upper surface (= the surface facing the positive side in the Z-axis direction).

  The position and size of the through hole PH11c coincide with the position and size of the through hole PH11a shown in FIG. 10, and the position and size of the through hole PH12c coincide with the position and size of the through hole PH12a shown in FIG. Similarly, the position and size of the through hole PH13c match the position and size of the through hole PH13a shown in FIG. 10, and the position and size of the through hole PH14c match the position and size of the through hole PH14a shown in FIG. .

  The position of the convex portion CV11c coincides with the position of the through hole PH11c, and the size of the top surface of the convex portion CV11c exceeds the size of the opening of the through hole PH11c. The position of the convex portion CV12c coincides with the position of the through hole PH12c, and the size of the top surface of the convex portion CV12c exceeds the size of the opening of the through hole PH12c. The position of the convex portion CV13c coincides with the position of the through hole PH13c, and the size of the top surface of the convex portion CV13c exceeds the size of the opening of the through hole PH13c. The position of the convex portion CV14c coincides with the position of the through hole PH14c, and the size of the top surface of the convex portion CV14c exceeds the size of the opening of the through hole PH14c.

  Therefore, one end of each of the through holes PH11c to PH14c is opened at the upper surface of the plate member 24c, the other end of the through hole PH11c is opened at the top surface of the convex portion CV11c, and the other end of the through hole PH12c is the top of the convex portion CV12c. The other end of the through hole PH13c opens at the top surface of the convex portion CV13c, and the other end of the through hole PH14c opens at the top surface of the convex portion CV14c.

  The height of the convex portion CV11c matches the depth of the concave portion CC11c, the height of the convex portion CV12c matches the depth of the concave portion CC12c, the height of the convex portion CV13c matches the depth of the concave portion CC13c, and the convex portion CV14c. Is equal to the depth of the recess CC14c.

  However, the diameter of the perfect circle forming the concave portion CC11c is slightly larger than the diameter of the perfect circle forming the convex portion CV11c, and the diameter of the perfect circle forming the concave portion CC12c is slightly larger than the diameter of the perfect circle forming the convex portion CV12c. Similarly, the diameter of the perfect circle forming the recess CC13c is slightly larger than the diameter of the perfect circle forming the protrusion CV13c, and the diameter of the perfect circle forming the recess CC14c is slightly larger than the diameter of the perfect circle forming the protrusion CV14c. .

  Therefore, when the plate member 24c is placed on the holder 26c so that the convex portions CV11c to CV14c fit into the concave portions CC11c to CC14c, the air supply holes HL11c to HL14c communicate with the through holes PH11c to PH14c, respectively. A slight gap is formed between the outer peripheral surface of the convex portion CV11c and the inner peripheral surface of the concave portion CC11c, and a slight gap is also formed between the outer peripheral surface of the convex portion CV12c and the inner peripheral surface of the concave portion CC12c. . A slight gap is also formed between the outer peripheral surface of the convex portion CV13c and the inner peripheral surface of the concave portion CC13c, and a slight gap is also formed between the outer peripheral surface of the convex portion CV14c and the inner peripheral surface of the concave portion CC14c. It is formed.

  Gas seal material 281c is filled in the gap between the outer peripheral surface of the convex portion CV11c and the inner peripheral surface of the concave portion CC11c, and the gas seal material 282c is filled in the gap between the outer peripheral surface of the convex portion CV12c and the inner peripheral surface of the concave portion CC12c. Is done. A gas seal material 283c is filled in a gap between the outer peripheral surface of the convex portion CV13c and an inner peripheral surface of the concave portion CC13c, and a gas seal material 284c is filled in a gap between the outer peripheral surface of the convex portion CV14c and the inner peripheral surface of the concave portion CC14c. Is done.

  The air taken in from the air supply holes HL11c and HL13c propagates upward through the through holes PH11c and PH13c, and the hydrogen gas taken in from the air supply holes HL12c and HL14c propagates upward through the through holes PH12c and PH14c. Leakage of air from between 26c and the plate material 24c is avoided by the gas sealing materials 281c and 283c, and leakage of hydrogen gas from between the holder 26c and the plate material 24c is avoided by the gas sealing materials 282c and 284c. Moreover, in this embodiment, since the concave portions CC11c to CC14c and the convex portions CV11c to CV14c are formed at positions separated from each other, mixing of air and hydrogen gas can be prevented.

  In the above-described embodiment, the plate material 14a is provided with the convex portions CV1a and CV2a, the plate material 14b is provided with the convex portions CV1b and CV2b, the plate material 24a is provided with the convex portions CV11a, CV12a and CV14a, and the plate material 24b is provided with the convex portions CV113b, CV12b and CV14b are provided, and convex portions CV11c to CV14c are provided on the plate member 24c. However, the plate members 14a, 14b, 24a to 24c are omitted, and the convex portions CV1a, CV2a, CV1b, CV2b, CV11a, CV12a, CV14a, CV113b, CV12b, and CV14b are provided on the lower surface of the lowermost fuel cell 12cl. Also good.

  In this case, convex portions CV1a and CV2a are provided on the lower surface of the fuel cell 12cl corresponding to the embodiment shown in FIG. 2, and the convex portions CV1b and CV2a are provided on the lower surface of the fuel cell 12cl corresponding to the embodiment shown in FIG. CV2b is provided. Further, convex portions CV11a, CV12a and CV14a are provided on the lower surface of the fuel cell 12cl corresponding to the embodiment shown in FIG. 10, and the convex portion CV113b is provided on the lower surface of the fuel cell 12cl corresponding to the embodiment shown in FIG. , CV12b, CV14b, and convex portions CV11c to CV14c are provided on the lower surface of the fuel cell 12cl corresponding to the embodiment shown in FIG.

  Referring to FIG. 17, a fuel cell unit 30 of another embodiment is a solid oxide fuel cell unit, and holds cylindrical fuel cell 32 in which a single manifold MF21 is formed and this. Plate-shaped holder 34. Also 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 holder 34.

  A cylindrical convex portion CV21 is formed on the lower surface of the fuel cell 32. One end of the manifold MF21 opens at the upper surface of the fuel cell 32, while the other end of the manifold MF21 opens at the top surface of the convex portion CV21. . The holder 34 is formed with a cylindrical recess CC21 that fits with the projection CV21, and an air supply hole HL21 for supplying hydrogen gas to the fuel cell 32 is opened at the bottom surface of the recess CC21. The diameter of the concave portion CC21 is slightly larger than the diameter of the convex portion CV21, and a gas seal material 36 is filled between the inner peripheral surface of the concave portion CC21 and the outer peripheral surface of the convex portion CV21.

  Also in this embodiment, the size of the concave portion CC21 and the convex portion CV21 is determined with reference to the time when the gas seal is formed (at the time of high temperature), so that the holder can be used regardless of whether the fuel cell unit 30 is in the operating state or the stopped state. The leakage of hydrogen gas from between the fuel cell 34 and the fuel cell 32 can be reliably prevented.

  Referring to FIG. 18, a fuel cell unit 40 of still another embodiment is a solid oxide fuel cell unit, and includes a rectangular parallelepiped fuel cell 42 and a plate-like holder 44 that holds the fuel cell unit 42. . Also 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 fuel cell unit 40.

  The size of the upper surface (= the surface facing the positive side in the Z-axis direction) of the holder 44 is larger than the size of the lower surface (= the surface facing the negative side in the Z-axis direction) of the fuel cell 42. Is provided at the center of the upper surface.

  Referring to FIGS. 19, 20 (A) to 20 (B), the upper surface of the holder 44 is formed with a recess CC <b> 31 extending in the X-axis direction with a rectangular cross section orthogonal to the Z-axis. The holder 44 is also provided with air supply holes HL31 to HL35 for supplying hydrogen gas taken in from the outside to the fuel cell 42. One end of each of the air supply holes HL31 to HL35 opens at the bottom surface of the recess CC31.

  Referring to FIGS. 19 and 21A to 21B, the fuel cell 42 has a convex portion CV31 protruding from the lower surface of the fuel cell 42 with a cross section orthogonal to the Z-axis being a rectangle. . The fuel cells 42 are also formed with manifolds MF31 to MF35 for taking in hydrogen gas. One end of each of manifolds MF31 to MF35 opens at the upper surface of fuel cell 42 (the surface facing the positive side in the Z-axis direction), and the other end of each of manifolds MF31 to MF35 opens at the top surface of convex portion CV31. .

  The height of the convex portion CV31 coincides with the depth of the concave portion CC31 formed in the holder 44. However, the width and length of the convex portion CV31 are slightly smaller than the width and length of the concave portion CC31. In addition, the size of one end of each of the air supply holes HL31 to HL35 matches each other, and further matches the size of the other end of each of the manifolds MF31 to MF35. Further, when viewed from the Z-axis direction, the opening position of one end of the air supply holes HL31 to HL35 overlaps with the opening position of the other end of the manifolds MF31 to MF35.

  Therefore, when the fuel cell 42 is placed on the holder 44 so that the convex portion CV31 is fitted to the concave portion CC31, the air supply holes HL31 to HL35 communicate with the manifolds MF31 to MF35, and the outer peripheral surface of the convex portion CV31 and the concave portion CC31. A slight gap is formed between the inner peripheral surface.

  Returning to FIG. 19, the gas seal material 46 is filled in the gap between the outer peripheral surface of the convex portion CV31 and the inner peripheral surface of the concave portion CC31. Hydrogen gas supplied through the air supply holes HL31 to HL35 is propagated to the manifolds MF31 to MF35, and leakage of hydrogen gas from between the holder 44 and the fuel cell 42 is prevented by the gas seal material 46 thus filled. Is done.

  Air is supplied to the air electrode from the side surface of the fuel cell 42 (= the surface orthogonal to the Y axis). Further, the hydrogen gas is supplied to the fuel electrode through the manifolds MF31 to MF35. The supplied air and hydrogen gas undergo chemical reactions according to the above-described chemical formulas 1 and 2. As a result, a positive voltage and a negative voltage are generated from the fuel cell 42.

The fuel cell 42 has a ceramic (for example, 3YSZ) as a main component, while the holder 44 has a metal (for example, a ferrite alloy) as a main component. Therefore, the thermal expansion coefficient of the holder 44 is larger than the thermal expansion coefficient of the fuel cell 42. Specifically, the thermal expansion coefficient of the former exceeds the thermal expansion coefficient of the latter in the range of less than 1 × 10 ⁻⁶ / ° C.

  The gas sealing material 46 filled in the gap between the outer peripheral surface of the convex portion CV31 and the inner peripheral surface of the concave portion CC31 is mainly composed of crystallized glass, and is softened at around 700 ° C. to soften the outer peripheral surface of the convex portion CV31. It closely adheres to the inner peripheral surface of the recess CC31. The softened gas sealing material 46 is crystallized in the vicinity of the operating temperature (= 900 ° C.) of the fuel cell 42.

  Also in this embodiment, due to the difference in coefficient of thermal expansion between the holder 44 and the fuel cell 42, the amount by which the inner peripheral surface of the recess CC31 moves inward when the temperature decreases is the outer peripheral surface of the protrusion CV31 when the temperature decreases. Is larger than the amount that moves inward. The pressure applied to the gas seal material 46 sandwiched between the inner peripheral surface of the concave portion CC31 and the outer peripheral surface of the convex portion CV31 increases as the temperature decreases.

  Therefore, by determining the sizes of the concave portion CC31 and the convex portion CV31 based on the time of operation (high temperature) of the fuel cell unit 40, the holder 44 can be used regardless of whether the fuel cell unit 40 is in an operating state or a stopped state. In addition, leakage of hydrogen gas from between the fuel cells 42 can be reliably prevented.

  In this embodiment, the five air supply holes HL31 to HL35 are formed in the holder 44. Instead, a single air supply hole HL41 is formed in the holder 44 and communicates with the manifolds MF31 to MF35. A single manifold MF41 may be formed in the fuel cell 42 (see FIGS. 22 and 23). Accordingly, the convex portion CV31 and the concave portion CV41 can be reduced in size, and the area of the gas seal material 46 can be reduced.

  In any of the above-described embodiments, crystallized glass is assumed as the main component of the gas seal material. However, instead of this, amorphous glass may be assumed, and a filler may be mixed into the gas seal material in order to increase strength and heat resistance.

10 ... Fuel cell unit 16a-16b, 26a-26b, 34 ... Holder (first member)
HL1a to HL2a, HL1b to HL2b, HL11a to HL14a, HL11b to HL14b, HL11c to HL14c, HL21 to HL25 ... supply holes (first supply holes)
12cl, 22cl, 32 ... Fuel cell (second member)
14a-14b, 24a-24c ... Plate material (second member)
PH1a to PH2a, PH1b to PH2b, PH11a to PH14a, PH11b to PH14b, PH11c to PH14c ... through hole (second air supply hole)
MF1 to MF2, MF11 to MF14, MF31 to MF35 ... Manifold (second air supply hole)
CC1a, CC2a, CC1b to CC2b, CC11a, CC12a, CC14a, CC113b, CC12b, CC14b, CC11c to CC14c, CC21, CC31 ... Recessed CV1a, CV2a, CV1b to CV2b, CV11a, CV12a, CV14a, CV113VC14, CV113C ~ CV14c, CV21, CV31 ... convex parts 181a to 182a, 181b to 182b, 281a, 282a, 284a, 2813b, 282b, 284b, 281c to 284c, 36, 46 ... gas seal material (seal material)

Claims (5)

A holder made of a first member having a first coefficient of thermal expansion and having a first main surface formed as an upper surface; and
Including a fuel cell stack with an adapter consisting of the second member second main surface is formed as a bottom surface of pre-Symbol contacting first major surface and the surface,
A fuel cell unit that generates electric power based on gas taken in through a first air supply hole provided in the first member and a second air supply hole provided in the second member and communicating with the first air supply hole Because
The adapter is composed mainly of ceramic, have a second thermal expansion coefficient lower than the first thermal expansion coefficient, is inserted between the holder and the fuel cell stack,
The first member has a recess formed in the first main surface,
The second member has a convex portion formed on the second main surface and fitted with the concave portion,
The first air supply hole and the second air supply hole open on the bottom surface of the concave portion and the top surface of the convex portion, respectively.
Further example Bei the filled sealing material between the inner peripheral surface and the outer peripheral surface of the convex portion of the concave portion,
A fuel cell unit capable of preventing leakage of air or hydrogen gas from between a concave portion and a convex portion regardless of whether the fuel cell unit is in an operating state or a stopped state . The gas includes aerobic gas and hydrogen gas,
The first air supply hole includes a first oxygen gas supply hole and a first hydrogen gas supply hole for supplying the oxygen gas and the hydrogen gas, respectively.
2. The fuel cell according to claim 1, wherein the second air supply hole includes a second oxygen gas supply hole and a second hydrogen gas supply hole that communicate with the first oxygen gas supply hole and the first hydrogen gas supply hole, respectively. unit.   The fuel cell unit according to claim 1, wherein the sealing material includes a glass material.   The fuel cell unit according to claim 3, wherein the glass material is one of crystallized glass and amorphous glass.   The fuel cell unit according to claim 3 or 4, wherein the sealing material further includes a filler.

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