Fuel cell

1. A fuel cell formed by stacking an electrolyte electrode assembly between separators, the electrolyte electrode assembly including an anode, a cathode and an electrolyte interposed between the anode and the cathode,

the fuel cell comprising an anode current collector provided between the anode and the separator, for collecting electrical energy generated in the electrolyte electrode assembly, and supplying a fuel gas to an electrode surface of the anode, the anode current collector being separate and distinct from the separator,

wherein the separator has a fuel gas inlet hole for supplying the fuel gas to the anode current collector;

the anode current collector has a fuel gas inlet channel having an opening that faces an opening of the fuel gas inlet hole at an end of the fuel gas inlet hole, for allowing the fuel gas supplied through the fuel gas inlet hole to flow into the anode current collector; and

the anode current collector has a first surface adjacent to the anode and a second surface opposite to the first surface and adjacent to the separator, and the fuel gas inlet channel is defined by an inner wall surrounding an empty space formed in the anode current collector that continuously extends from the first surface to the second surface and passes entirely through the anode current collector.

2. The fuel cell according to claim 1 , wherein the cross sectional area of the opening of the fuel gas inlet channel is larger than the cross sectional area of the opening of the fuel gas inlet hole, such that a portion of a surface of the separator surrounding the opening of the fuel gas inlet hole is exposed from the anode current collector through the opening of the fuel gas inlet channel.

3. The fuel cell according to claim 1 , wherein the anode current collector is made of foamed metal.

4. A fuel cell formed by stacking an electrolyte electrode assembly between separators, the electrolyte electrode assembly including an anode, a cathode and an electrolyte interposed between the anode and the cathode,

the fuel cell comprising an anode current collector provided between the anode and the separator, for collecting electrical energy generated in the electrolyte electrode assembly, and supplying a fuel gas to an electrode surface of the anode, the anode current collector being separate and distinct from the separator,

wherein the separator has at least one fuel gas inlet hole for supplying the fuel gas to the anode current collector;

the anode current collector has at least one fuel gas inlet channel having an opening that faces an opening of the fuel gas inlet hole at an end of the fuel gas inlet hole, for allowing the fuel gas supplied through the fuel gas inlet hole to flow into the anode current collector; and

in the anode current collector, an inner wall forming the fuel gas inlet channel is denser than portions other than the inner wall.

5. The fuel cell according to claim 1 , wherein the electrolyte electrode assembly is an anode supported electrolyte electrode assembly having the anode as a supporting substrate.

6. The fuel cell according to claim 1 , wherein the thickness of the anode current collector is smaller than the thickness of the anode.

7. The fuel cell according to claim 1 , wherein a densification treatment is performed on an outer peripheral portion of the anode current collector.

8. The fuel cell according to claim 1 , wherein the fuel cell is a solid oxide fuel cell.

9. The fuel cell according to claim 1 , wherein the fuel cell is a flat-plate type solid oxide fuel cell.

10. The fuel cell according to claim 1 , wherein

each of the separators comprise: a first plate; and a second plate joined to the first plate, and

the anode current collector is provided between the anode and one of the first plate and the second plate of the separator.

11. The fuel cell according to claim 1 , wherein, in the anode current collector, at least a portion of the inner wall forming the fuel gas inlet channel and surrounding the empty space is spaced from the separator.

12. The fuel cell according to claim 1 , wherein a cross sectional area of the opening of the fuel gas inlet channel at the second surface is smaller than a cross sectional area of an opening of the fuel gas inlet channel at the first surface.

13. The fuel cell according to claim 1 , wherein, in the anode current collector, an outer peripheral portion is denser than portions other than the outer peripheral portion.