Fuel cell device and systems enabling cell-level repair
A unit cell for a fuel cell stack including an anode catalyst layer separated by a polymer electrolyte membrane from a cathode catalyst layer, a first cell end plate separated by a first gas diffusion layer from the anode catalyst layer, and a second cell end plate separated by a second gas diffusion layer from the cathode catalyst layer, wherein the first cell end plate, the second cell end plate, or both include a matrix of electrically-conducting protrusions thereof.
1. A proton exchange membrane fuel cell stack comprising:
a plurality of individual fuel cell units disposed between first and second stack end plates and including first, second, and third fuel cell units, the second fuel cell unit disposed between the first and third fuel cell units, each fuel cell including at least two gas diffusion layers and at least two catalyst layers separated by an electrolyte membrane, the first fuel cell unit including first and second flow field plates, the second fuel cell unit including first and second flow field plates, the third fuel cell unit including first and second flow field plates, the second flow field plate of the first fuel cell unit is adjacent the first flow field of the second fuel cell unit, the second flow field plate of the second fuel cell unit is adjacent the first flow field plate of the third fuel cell unit, one of the second flow field plate of the first fuel cell unit and the first flow field of the second fuel cell unit comprising a matrix of electrically-conducting protrusions extending from a surface of the one flow field plate facing the other flow field plate and the other flow field plate comprising a matrix of electrically-conducting receiving structures extending into the other flow field plate and engaging the matrix of electrically-conducting protrusions, the matrix of electrically-conducting protrusions having a protrusion length, the matrix of electrically-conducting receiving structures having a receiving structure length equal to the protrusion length, the matrix of electrically-conducting receiving structures positioned about an edge region of the other flow field plate and a middle region of the other flow field plate within the edge region of the other flow field plate.
2. The proton exchange membrane fuel cell stack of claim 1 , wherein the plurality of individual fuel cell units includes between 100 and 500 individual fuel cell units.
3. The proton exchange membrane fuel cell stack of claim 1 , wherein the matrix of electrically-conducting protrusions extend between 0.01 mm and 2 mm from the surface of the one flow field plate facing the other flow field plate.
4. The proton exchange membrane fuel cell stack of claim 1 , wherein the plurality of electrically-conducting receiving structures extend into the surface of the other flow field plate facing the one flow field plate a length of between 0.01 mm and 2 mm.
5. The proton exchange membrane fuel cell stack of claim 1 , wherein the matrix of electrically-conducting protrusions comprise copper, steel, nickel, or a combination thereof and include a protective coating on at least a portion thereof.
6. The proton exchange membrane fuel cell stack of claim 1 , wherein the plurality of electrically-conducting receiving structures include a protective coating on at least a portion thereof.
7. A proton exchange membrane fuel cell stack comprising:
a plurality of individual fuel cell units disposed between first and second stack end plates and including first, second, and third fuel cell units, the second fuel cell unit disposed between the first and third fuel cell units, each fuel cell including at least two gas diffusion layers and at least two catalyst layers separated by an electrolyte membrane, the first fuel cell unit including first and second flow field plates, the second fuel cell unit including first and second flow field plates, the third fuel cell unit including first and second flow field plates, the second flow field plate of the first fuel cell unit is adjacent the first flow field of the second fuel cell unit, the second flow field plate of the second fuel cell unit is adjacent the first flow field plate of the third fuel cell unit, one of the second flow field plate of the first fuel cell unit and the first flow field of the second fuel cell unit comprising a matrix of electrically-conducting tubes extending from a surface of the one flow field plate facing the other flow field plate and the other flow field plate comprising a matrix of electrically-conducting sockets extending into the other flow field plate and engaging the matrix of electrically-conducting tubes, the matrix of electrically-conducting tubes having a tube length, and the matrix of electrically-conducting sockets having a socket length equal to the tube length, the matrix of electrically-conducting sockets positioned about an edge region of the other flow field plate and a middle region of the other flow field plate within the edge region of the other flow field plate.
8. The unit cell of claim 7 , wherein the matrix of electrically-conducting tubes are wires formed from copper, steel, and/or nickel.
9. The unit cell of claim 7 , wherein the matrix of electrically-conducting tubes comprise the same material as the one flow field plate.
10. The unit cell of claim 7 , wherein the matrix of electrically-conducting tubes include one or more protective oxide coatings applied to at least a portion its surface.
11. The unit cell of claim 7 , wherein the matrix of electrically-conducting tubes extend between 0.01 mm and 2 mm from the surface of the one flow field plate facing the other flow field plate.
12. The unit cell of claim 7 , wherein the one flow field plate having the matrix of electrically-conducting tubes exhibits an electrical conductivity of between 0.1 and 100 S/cm.
13. A proton exchange membrane fuel cell stack comprising:
a first fuel cell unit including first and second flow field plates and a first membrane electrode assembly therebetween, the first or second flow field plate of the first fuel cell unit includes rectangular-shaped protrusions extending from an outer surface thereof and having a protrusion length; and
a second fuel cell unit including first and second flow field plate and a second membrane electrode assembly therebetween, the first or second flow field plate of the second fuel cell unit includes rectangular-shaped receptors having a receptor length, extending into the first or second flow field plate of the second fuel cell unit and engaging the protrusions, the protrusion length and the receptor length are equal; and
wherein the protrusions are a matrix of electrically-conducting protrusions and the receptors are a matrix of electrically-conducting receptors; and
the matrix of electrically-conducting sockets positioned about an edge region of the other flow field plate and a middle region of the other flow field plate within the edge region of the other flow field plate.
14. The proton exchange membrane fuel cell stack of claim 13 , wherein the protrusions include an unequal number of rows and columns.
15. The proton exchange membrane fuel cell stack of claim 14 , wherein the receptor and the protrusion lengths are in a range of 0.01 to 2 mm.
16. The proton exchange membrane fuel cell stack of claim 13 , wherein the receptors include an unequal number of rows and columns.
17. The proton exchange membrane fuel cell stack of claim 13 , wherein the protrusions are dimpled-shaped receptors.
18. The proton exchange membrane fuel cell stack of claim 13 , wherein the protrusions are tubes having distal tube surfaces and the receptors are sockets having bottom socket surfaces, the protrusion length and the receptor length are equal such that the distal tube surfaces flush with the bottom sockets surfaces to enhance electrical connection between the first and second fuel cell units.