Unit cell of solid oxide fuel cell, stack using the unit cell, and methods of manufacturing the unit cell and the stack

Patent metadata

Field	Value
Publication number	US-9831517-B2
Application number	US-201514838138-A
Country	US
Kind code	B2
Filing date	Aug 27, 2015
Priority date	Aug 27, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A unit cell includes an air inlet/outlet that is formed on a frame unit rather than being installed in a fuel electrode (anode) to simplify a sealing process, and accordingly, a continuous process using a tape casting technique may be performed. In addition, an electrolyte material that is in contact with an air electrode (cathode) in the frame unit is optimized to improve ion conductivity and a porosity of an upper layer material of the fuel electrode unit is optimized to increase fuel diffusion from a gas channel to an electrolyte layer. In addition, a sealing process performed inside the unit cell or between the unit cells of the stack is stabilized and strongly maintained, and thus a fuel cell using the unit cell and the stack disclosed herein may have excellent economic feasibility and high energy efficiency.

First claim

What is claimed is:

1. A fuel cell comprising:
a fuel electrode body comprising a first major surface and a second major surface facing away from the first major surface, the fuel electrode body further comprising a plurality of side surfaces connecting the first and second major surfaces, the plurality side surfaces comprising a first side surface and a second side surface facing away from the first side surface;
a frame formed of at least one electrolyte material and comprising a plurality of rim portions which surround the plurality of side surfaces of the fuel electrode body when viewed in a viewing direction perpendicular to the first major surface, the plurality of rim portions comprising a first rim portion extending from the first side surface and a second rim portion extending from the second side surface, the frame further comprising an upper wall disposed on and contacting the first major surface of the furl electrode body;
an interconnector positioned under the fuel electrode body, the interconnector contacting the second major surface of the fuel electrode body;
an air electrode disposed on and contacting the upper wall of the frame, wherein the upper wall is disposed between the air electrode and the fuel electrode body;
a first vertical gas channel formed through the first rim portion;
a second vertical gas channel formed through the second rim portion; and
at least one horizontal gas channel formed through the fuel electrode body and disposed between the first major surface and the second major surface, the at least one horizontal gas channel extending between the first and second vertical gas channels.

2. The fuel of claim 1 , wherein the frame is made of 3 mol % to 8 mol % of Y 2 P 3 -doped zirconia.

3. The fuel cell of claim 2 , wherein the upper wall of the frame is made of an electrolyte material that is different from the rest of the frame and selected from the group consisting of zirconia doped with scandium (Sc) or ytterbium (Yb), ceria doped with yttrium (Y), gadolinium (Gd), or samarium (Sm), and LaGaO 3 dope with strontium (Sr) and magnesium (Mg).

4. The fuel cell of claim 1 , wherein the fuel electrode body comprises a composite comprising an ion conductive electrolyte material and at least one selected from the group consisting of a nickel, a nickel alloy, and an iron-based alloy,
wherein the ion conductive electrolyte material comprises at least one selected from the group consisting of a yttria-stabilized zirconia (YSZ), a scandia-a stabilized zirconia (ScSZ), a Gd doped-ceria (GDC), a Sm doped-ceria, and a lanthanum gallates.

5. The fuel cell of claim 1 , wherein the interconnector is formed of a ceramic or a composite of a ceramic and an ion conductive electrolyte material,
wherein the ceramic comprises at least one selected from the group consisting of a strontium titanium ferrite (STF), a lanthanum strontium ferrite (LSF), a LSF comprising Sc (LSFSc), a lanthanum calcium ferrite (LCF), a lanthanum strontium manganite (LSM), a lanthanum strontium cobatite (LSC), a lanthanum strontium chromite (LSCr), a lanthanum strontium cobalt ferrite (LSCF), a manganese ferrite (MnFe 2 O 4 ) and nickel ferrite (NiFe 2 O 4 ), and wherein the ion conductive electrolyte material comprises a Gd doped-ceria (GDC) or a La doped-ceria.

6. The fuel cell of claim 1 , wherein the fuel electrode body comprises a fuel diffusion layer and a fuel electrode support that is disposed between the fuel diffusion layer and the interconnector, wherein the fuel diffusion layer has a porosity greater than that of the fuel electrode support,
wherein the fuel diffusion layer has a porosity of at least about 30%, and
wherein the fuel diffusion layer contacts the upper wall of the frame,
wherein the at least one horizontal gas channel is formed between the fuel diffusion layer and the fuel electrode support.

7. The fuel cell of claim 1 , wherein the fuel electrode body is formed of a composite comprising nickel (Ni) and YSZ, and
wherein the fuel cell further comprises an Ni-GDC composite layer disposed between the fuel electrode body and the interconnector.

8. The fuel cell of claim 1 , wherein the plurality of side surfaces of the fuel electrode body further comprise a third side surface and a fourth side surface facing away from the third side surface,
wherein the plurality of rim portions of the frame further comprise a third rim portion extending from the third side surface and a fourth rim portion extending from the fourth side surface,
wherein the fuel cell further comprises:
a first vertical air channel formed through the third rim portion, and
a second vertical air channel formed through the fourth rim portion.

9. A fuel cell assembly comprising a plurality of fuel cells, each of which is the fuel cell of claim 1 , wherein the plurality of fuel cells comprises a first fuel cell and the second fuel cell, wherein the second fuel cell is placed over the first fuel cell such that the first vertical gas channel of the first fuel cell overlaps the first vertical gas channel of the second fuel cell when viewed in the viewing direction and further such that the second vertical gas channel of the first fuel cell overlaps the second vertical gas channel of the second fuel cell when viewed in the viewing direction.

10. The fuel cell assembly of claim 9 , wherein the plurality of side surfaces of the fuel electrode body of each fuel cell further comprise a third side surface and a fourth side surface facing away from the third side surface,
wherein the plurality of rim portions of the frame of each fuel cell further comprise a third rim portion extending from the third side surface and a fourth rim portion extending from the fourth side surface,
wherein each fuel cell further comprises:
a first vertical air channel formed through the third rim portion, and
a second vertical air channel formed through the fourth rim portion.

11. The fuel cell assembly of claim 10 , wherein the second fuel cell is placed over the first fuel cell such that the first vertical air channel of the first fuel cell overlaps the first vertical air channel of the second fuel cell when viewed in the viewing direction and further such that the second vertical air channel of the first fuel cell overlaps the second vertical air channel of the second fuel cell when viewed in the viewing direction.

12. The fuel cell assembly of claim 11 , further comprising a plate disposed between the interconnector of the second fuel cell and the air electrode of the first fuel cell, wherein the plate comprises at least one groove for providing at least one horizontal air channel formed between the plate and the interconnector of the second fuel cell, the at least one horizontal air channel extending between the first and second vertical air channels.

Assignees

• Korea Inst Energy Res
• Koea Institute Of Energy Res

Inventors

• Yu Ji Haeng
• Joo Jong Hoon
• Yoo Chung-Yul

Classifications

• H01M2300/0077

  based on zirconium oxide · CPC title

• H01M8/1231 Primary

  with both reactants being gaseous or vaporised · CPC title

• Y02P70/56

  Cross-Sectional Technologies · mapped topic

• H01M8/0273

  with sealing or supporting means in the form of a frame · CPC title

• H01M4/8857

  Casting, e.g. tape casting, vacuum slip casting · CPC title