Fuel cell stack

Abstract

A fuel cell stack is formed by stacking a plurality of fuel cells each of which is formed by stacking electrolyte electrode assemblies and a separator alternately. A channel member is joined to the separator to form a fuel gas supply channel between the separator and the channel member. The fuel gas supply channel is connected to a fuel gas channel through a fuel gas inlet, and connected to an internal chamber. The internal chamber is connected to a fuel gas storage chamber through a fuel gas intake port to form a fuel gas supply unit. When a plurality of the separators are stacked together, the fuel gas supply unit forms the chamber extending in the stacking direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically showing a fuel cell stack formed by stacking fuel cells according to a first embodiment of the present invention;

FIG. 2 is an exploded perspective view showing the fuel cell;

FIG. 3 is a partial exploded perspective view showing gas flows in the fuel cell;

FIG. 4 is a view showing a separator;

FIG. 5 is a cross sectional view schematically showing operation of the fuel cell;

FIG. 6 is a perspective view showing a main portion of the fuel cell;

FIG. 7 is an exploded perspective view showing a fuel cell used in a fuel cell stack according to a second embodiment of the present invention;

FIG. 8 is a front view showing a separator of the fuel cell;

FIG. 9 is a cross sectional view schematically showing operation of the fuel cell;

FIG. 10 is an exploded perspective view showing a fuel cell used in a fuel cell stack according to a third embodiment of the present invention;

FIG. 11 is a cross sectional view schematically showing operation of the fuel cell;

FIG. 12 is an exploded perspective view showing a fuel cell used in a fuel cell stack according to a fourth embodiment of the present invention;

FIG. 13 is a cross sectional view schematically showing operation of the fuel cell;

FIG. 14 is perspective view schematically showing a fuel cell stack formed by stacking fuel cells according to a fifth embodiment of the present invention;

FIG. 15 is an exploded perspective view showing the fuel cell;

FIG. 16 is a partial exploded perspective view showing gas flows in the fuel cell;

FIG. 17 is a cross sectional view schematically showing operation of the fuel cell;

FIG. 18 is a perspective view schematically showing a fuel cell stack formed by stacking fuel cells according to a sixth embodiment of the present invention;

FIG. 19 is an exploded perspective view showing the fuel cell;

FIG. 20 is a cross sectional view showing operation of the fuel cell; and

FIG. 21 is a view showing a conventional fuel cell.

Claims

1. A fuel cell stack formed by stacking a plurality of fuel cells, each of which is formed by stacking an electrolyte electrode assembly and a separator, said electrolyte electrode assembly including an anode, a cathode, and an electrolyte interposed between said anode and said cathode, said fuel cell comprising: a fuel gas channel provided on one surface of said separator for supplying a fuel gas along a surface of said anode;an oxygen-containing gas channel provided on the other surface of said separator for supplying an oxygen-containing gas along a surface of said cathode;a fuel gas supply passage extending in a stacking direction of said separator for allowing the fuel gas to flow in the stacking direction;a fuel gas supply unit provided in said separator for dividing the flow of the fuel gas, and supplying the fuel gas from said fuel gas supply passage to said fuel gas channel of said separator,wherein said fuel gas supply unit forms a chamber extending through said separators in the stacking direction when said fuel cells are stacked together.

2. A fuel cell stack according to claim 1, wherein said fuel gas supply unit comprises: a fuel gas storage chamber connected to said fuel gas supply passage;a fuel gas intake port connected to said fuel gas storage chamber for taking the fuel gas from said fuel gas storage chamber; anda fuel gas supply channel for supplying the fuel gas taken from said fuel gas intake port to said fuel gas channel,wherein said separator has a fuel gas inlet connecting said fuel gas supply channel and said fuel gas channel for supplying the fuel gas to said anode; andthe pressure loss at said fuel gas intake port is larger than the pressure loss at said fuel gas supply passage.

3. A fuel cell stack according to claim 2, wherein the total opening area of said fuel gas intake port is smaller than the total opening area of said fuel gas supply passage.

4. A fuel cell stack according to claim 2, the pressure loss at said fuel gas intake port is larger than the pressure loss at said fuel gas inlet.

5. A fuel cell stack according to claim 4, wherein the flow rate of the fuel gas at said fuel gas intake port is larger than the flow rate of the fuel gas at said fuel gas inlet.

6. A fuel cell stack according to claim 2, wherein said fuel gas supply unit is branched into a plurality of said fuel gas supply channels; and a plurality of said electrolyte electrode assemblies are provided along a surface of said separator for each of said fuel gas supply channels.

7. A fuel cell stack according to claim 6, wherein said fuel gas supply unit is provided at the center of said separator; and a plurality of said electrolyte electrode assemblies are arranged on one virtual circle around said fuel gas supply unit.

8. A fuel cell stack according to claim 7, wherein said fuel gas supply unit has an internal chamber connected to said fuel gas storage chamber through said fuel gas intake port; and said internal chamber is connected to a plurality of said fuel gas supply channels.

9. A fuel cell stack according to claim 2, wherein said separator comprises a single plate; said fuel gas channel is provided between one surface of said plate and said anode;said oxygen-containing gas channel is provided between the other surface of said plate and said cathode; anda fuel gas channel member forming said fuel gas supply channel is provided on the one surface or on the other surface of said plate.

10. A fuel cell stack formed by stacking a plurality of fuel cells, each of which is formed by stacking an electrolyte electrode assembly and a separator, said electrolyte electrode assembly including an anode, a cathode, and an electrolyte interposed between said anode and said cathode, said fuel cell comprising: a fuel gas channel provided on one surface of said separator for supplying a fuel gas along a surface of said anode;an oxygen-containing gas channel provided on the other surface of said separator for supplying an oxygen-containing gas along a surface of said cathode;an oxygen-containing gas supply passage extending through said separator in a stacking direction for allowing the oxygen-containing gas to flow in the stacking direction; andan oxygen-containing gas supply unit provided in said separator for dividing the flow of the oxygen-containing gas from said oxygen-containing gas supply passage, and supplying the oxygen-containing gas to said oxygen-containing gas channel,wherein said oxygen-containing gas supply unit forms a chamber extending in the stacking direction when said fuel cells are stacked together.

11. A fuel cell stack formed by stacking a plurality of fuel cells, each of which is formed by stacking an electrolyte electrode assembly and a separator, said electrolyte electrode assembly including an anode, a cathode, and an electrolyte interposed between said anode and said cathode, said fuel cell comprising: a fuel gas channel provided on one surface of said separator for supplying a fuel gas along a surface of said anode;an oxygen-containing gas channel provided on the other surface of said separator for supplying an oxygen-containing gas along a surface of said cathode;a fuel gas supply passage extending through said separator in a stacking direction for allowing the fuel gas to flow in the stacking direction;an oxygen-containing gas supply passage extending though said separator in the stacking direction for allowing the oxygen-containing gas to flow in the stacking direction;a fuel gas supply unit provided in said separator for dividing the flow of the fuel gas from said fuel gas supply passage and supplying the fuel gas to said fuel gas channel;an oxygen-containing gas supply unit provided in said separator for dividing the flow of the oxygen-containing gas from said oxygen-containing gas supply passage, and supplying the oxygen-containing gas to said oxygen-containing gas channel; andsaid fuel gas supply unit and said oxygen-containing gas supply unit form chambers, respectively extending in the stacking direction when said fuel cells are stacked together.

12. A fuel cell stack according to claim 11, wherein said fuel gas supply unit comprises a fuel gas storage chamber connected to said fuel gas supply passage; a fuel gas intake port connected to said fuel gas storage chamber for taking the fuel gas from said fuel gas storage chamber;a fuel gas supply channel for supplying the fuel gas taken from said fuel gas intake port to said fuel gas channel,wherein said oxygen-containing gas supply unit comprises an oxygen-containing gas storage chamber connected to said oxygen-containing gas supply passage;an oxygen-containing gas intake port connected to said oxygen-containing gas storage chamber for taking the oxygen-containing gas from said oxygen-containing gas storage chamber; andan oxygen-containing gas supply channel for supplying the oxygen-containing gas taken from said oxygen-containing gas intake port to said oxygen-containing gas channel.

13. A fuel cell stack according to claim 12, wherein said separator has a fuel gas inlet connecting said fuel gas supply channel and said fuel gas channel for supplying the fuel gas to said anode; and the pressure loss at said fuel gas intake port is larger than the pressure loss at said fuel gas supply passage.

14. A fuel cell stack according to claim 12, wherein said separator has an oxygen-containing gas inlet connecting said oxygen-containing gas supply channel and said oxygen-containing gas channel for supplying the oxygen-containing gas to said cathode; and the pressure loss at said oxygen-containing gas intake port is larger than the pressure loss at said oxygen-containing gas supply passage.

15. A fuel cell stack according to claim 12 wherein said separator comprises first to third plates which are stacked together; said fuel gas channel is formed between said first plate and said anode, and said oxygen-containing gas channel is formed between said third plate and said cathode; andsaid fuel gas supply channel is formed between said first plate and said second plate and said oxygen-containing gas supply channel is formed between said third plate and said second plate.