Separator-fitted single fuel cell inducing joint portion with protruding portion and sealing portion, and fuel cell stack
A separator-fitted single fuel cell having a single fuel cell, a plate-shaped metallic separator that includes a through hole, and a joint portion that joins the single fuel cell to the metallic separator and is made of a brazing material containing Ag. The joint portion includes a protruding portion that protrudes from a gap between the single fuel cell and the first main surface of the metallic separator toward the through hole. The protruding portion is lower than the second main surface as viewed from the single fuel cell. The single fuel cell includes a sealing portion that is disposed along the entire circumference of the through hole of the metallic separator, covers the protruding portion and a part of the second main surface, and is made of a sealing material containing glass.
1. A separator-fitted single fuel cell comprising:
a single fuel cell that includes a cathode, an anode, and a solid electrolyte layer disposed between the cathode and the anode;
a plate-shaped metallic separator that has a first main surface, a second main surface facing an opposite direction from the first main surface, and a through hole passing through the metallic separator between the first and second main surfaces;
a sealing portion disposed along an entire circumference of the through hole, the sealing portion being made of a sealing material containing glass; and
a joint portion that joins the solid electrolyte layer of the single fuel cell to the first main surface of the metallic separator,
the joint portion being made of a brazing material containing Ag,
the joint portion including a protruding portion that protrudes from a gap between the solid electrolyte layer of the single fuel cell and the first main surface of the metallic separator toward the through hole,
the protruding portion having a height from a surface of the solid electrolyte layer facing the first main surface that is less than a distance from the surface of the solid electrolyte layer facing the first main surface to the second main surface as viewed from the single fuel cell,
wherein the sealing portion covers the protruding portion and a part of the second main surface.
2. A separator-fitted single fuel cell according to claim 1 , wherein the height of the protruding portion from the surface of the solid electrolyte layer facing the first main surface is greater than a distance from the surface of the solid electrolyte layer facing the first main surface to the first main surface as viewed from the single fuel cell.
3. A separator-fitted single fuel cell according to claim 1 , wherein the metallic separator contains Al in an amount of 1.5 mass % or more to 10 mass % or less,
wherein the joint portion contains an oxide of Al or a complex oxide of Al in an amount of 1 volume % or more to 25 volume % or less, and
wherein the sealing portion contains Al in an amount of 1 mass % or more to 30 mass % or less as reduced to Al 2 O 3 .
4. A separator-fitted single fuel cell according to claim 3 , wherein the oxide of Al or the complex oxide of Al includes Al 2 O 3 , an Al-containing spinel oxide, or mullite.
5. A fuel cell stack comprising:
a plurality of separator-fitted single fuel cells, each of said separator-fitted single fuel cells comprising:
a single fuel cell that includes a cathode, an anode, and a solid electrolyte layer disposed between the cathode and the anode;
a plate-shaped metallic separator that has a first main surface, a second main surface facing in an opposite direction from the first main surface, and a through hole passing through the metallic separator between the first and second main surfaces;
a sealing portion disposed along an entire circumference of the through hole, the sealing portion being made of a sealing material containing glass; and
a joint portion that joins the solid electrolyte layer of the single fuel cell to the first main surface of the metallic separator, the joint portion being made of a brazing material containing Ag, the joint portion including a protruding portion that protrudes from a gap between the solid electrolyte layer of the single fuel cell and the first main surface of the metallic separator toward the through hole, the protruding portion having a height from a surface of the solid electrolyte layer facing the first main surface that is less than a distance from the surface of the solid electrolyte layer facing the first main surface to the second main surface as viewed from the single fuel cell,
wherein the sealing portion covers the protruding portion and a part of the second main surface.