1. A fuel cell system comprising a fuel cell stack including end plates at opposing ends of the fuel cell stack, said fuel cell stack further including at least one positive temperature coefficient (PTC) ceramic heater for heating the fuel cell stack, said at least one PTC ceramic heater including a ceramic body being made of a ceramic material and electrodes, said electrodes being responsive to an electrical current to cause the ceramic body to provide heat, said ceramic material in the ceramic body being designed to provide heat up unto a predetermined temperature at which the resistance of the ceramic body goes up, significantly reducing the ceramic bodies heat generation capability.
2. The system according to claim 1 wherein the at least one PTC ceramic heater is a ring heater positioned in a housing of the fuel cell stack.
3. The system according to claim 2 wherein the at least one PTC ceramic heater is positioned in the end plates of the fuel cell stack.
4. The system according to claim 3 wherein the at least one PTC ceramic heater is positioned in a recess between two end plates at each end of the fuel cell stack.
5. The system according to claim 4 wherein the recess is formed in the end plates by a stamping process or a molding process.
6. The system according to claim 4 wherein the at least one PTC ceramic heater is a plurality of PTC ceramic heaters disposed in a predetermined configuration between the end plates of the fuel cell stack.
7. The system according to claim 1 further comprising a hydrogen source, a hydrogen supply line in fluid communication with the hydrogen source and the fuel cell stack, and a PTC ceramic heater assembly positioned in contact with the hydrogen supply line so as to heat the hydrogen from the hydrogen source.
8. The system according to claim 7 wherein the PTC ceramic heater assembly includes a plurality of spaced apart ceramic ring heaters disposed around the supply line.
9. The system according to claim 8 further comprising a heat conducting metal positioned between the ring heaters and the supply line.
10. The system according to claim 7 wherein the hydrogen source is a compressed hydrogen tank.
11. The system according to claim 1 wherein the fuel cell system is on a vehicle.
12. A fuel cell system comprising:
a hydrogen source;
fuel cell stack;
a hydrogen supply line coupled to the hydrogen source and the fuel cell stack;
a positive temperature coefficient (PTC) ceramic heater assembly positioned in contact with the hydrogen supply line so as to heat the hydrogen from the hydrogen source, wherein the PTC ceramic heater assembly includes a plurality of spaced apart ceramic ring heaters disposed concentrically around the supply line; and
a heat conducting metal positioned between the ring heaters and the supply line.
13. The system according to claim 12 wherein the hydrogen source is a compressed hydrogen tank.
14. The system according to claim 12 wherein the fuel cell system is on a vehicle.
15. A fuel cell system comprising:
a fuel cell stack including opposing end plates at both ends of the fuel cell stack, said fuel cell stack further including a plurality of positive temperature coefficient (PTC) ceramic heaters for heating the fuel cell stack, said PTC ceramic heaters being positioned with recesses in the opposing end plates, each of the PTC ceramic heater including a ceramic body being made of a ceramic material and electrodes, said electrodes being responsive to an electrical current to cause the ceramic body to provide heat, said ceramic material in the ceramic body being designed to provide heat up unto a predetermined temperature at which the resistance of the ceramic body goes up, significantly reducing the ceramic bodies heat generation capability;
a compressed hydrogen storage tank;
a hydrogen supply line coupled to the hydrogen source and the fuel cell stack; and
a PTC ceramic heater assembly positioned in contact with the hydrogen supply line so as to heat the hydrogen from the hydrogen source, said PTC heater assembly including a plurality of spaced apart ceramic ring heaters disposed around the supply line.
16. The system according to claim 15 wherein the plurality of PTC ceramic heaters are ring heaters positioned in the recess between the opposing end plates at each end of the fuel cell stack.
17. The system according to claim 15 further comprising a heat conducting metal positioned between the ring heaters in the PTC ceramic heater assembly.
18. The system according to claim 15 wherein the fuel cell system is on a vehicle.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for making superconducting material useful for forming electrolytic devices comprising the steps of:
a) establishing multiple niobium or tantalum components in a primary billet of a ductile material;
b) working the primary billet to a series of reduction steps to form said niobium or tantalum components into rounded elongated elements;
c) cutting the rounded elongated elements from step b) and forming the cut elements into a stack around a metal core;
d) surrounding the stack of cut and stacked elements from step c) with a porous confining layer to form a secondary billet;
e) working the secondary billet from step d) through a series of reduction steps including twisting and rolling, to flatten the stacked elements into thin ribbon so that each of the flatten elements having an Aspect Ratio of greater than 5:1;
f) cutting the worked billet from step e) into sections; and
g) leaching the core and sheath at least in part.
2. The process of claim 1, wherein said leaching is in an acid leach.
3. The process of claim 1, wherein said leaching step is in a liquid metal bath.
4. The process of claim 3, wherein said liquid metal bath comprises molten magnesium.
5. The process of claim 1, wherein said porous confining layer contains a gap that renders the confining layer circumferentially discontinuous, but overlapping.
6. The process of claim 1, wherein said porous confining layer contains a gap that renders the confining layer circumferentially discontinuous.
7. The process of claim 1, wherein several separate segments are used to construct a multi anode capacitor assembly.
8. The process of claim 1, wherein said metal core consists of a single metal rod.
9. The process of claim 8, wherein said single metal rod has a cross-sectional area not exceeding 20% of said secondary billet before working.
10. The process of claim 1, wherein the Aspect Ratio is 40:1.