Optimizing hydrogen generating efficiency in fuel cell cartridges
View Patent ↗The present invention involves modifying certain characteristics of solid and aqueous chemical metal hydride fuels to increase the efficiency of hydrogen generation and/or to reduce the problems associated with such conventional hydride fuel sources. The present invention also relates to an apparatus ( 10 ) usable with the release of hydrogen from hydride-water fuel cells in which both the borohydride ( 110 ) and the water ( 210 ) components are in flowable or liquid form.
1. A method for increasing the efficiency of a metal hydride hydrogen-generating cartridge comprising the steps of:
forming a metal hydride slurry from a solid metal hydride and a liquid that is not reactive therewith in the absence of a stabilizing agent;
providing the metal hydride slurry in a separate compartment of the hydrogen-generating cartridge;
providing a predetermined amount of liquid reactant comprising predominantly water;
pressuring the metal hydride slurry, and
contacting the pressurized metal hydride slurry with the liquid reactant to create a reaction that generates hydrogen.
2. The method of claim 1 further comprising the step of grinding the solid metal borohydride, which has a first average particle size to a second average particle size that is smaller than the first average particle size before forming the metal hydride slurry.
3. The method of claim 2 , wherein the second average particle size is not more than about 25% of the first average particle size.
4. The method of claim 1 , wherein the metal hydride slurry is sufficiently flowable to enable liquid transport thereof.
5. The method of claim 1 , wherein the solid metal hydride is partially dissolved in the non-reactive liquid.
6. The method of claim 1 , wherein the metal hydride comprises sodium borohydride.
7. The method of claim 2 , wherein the step of increasing the surface area comprises grinding the second average particle size is about 0.5 mm or less.
8. The method of claim 7 , wherein the second average particle size is about 0.25 mm or less.
9. The method of claim 1 , wherein the liquid that is not reactive therewith in the absence of a stabilizing agent is an inorganic liquid.
10. The method of claim 1 , wherein the liquid reactant is pressurized before contacting the metal hydride slurry.
11. A method for producing hydrogen comprising the steps of:
dissolving a solid metal hydride fuel in a liquid comprising ammonia, hydrazine, tetraethyleneglycoldimethylether, or triethyleneglycoldimethylether, or a combination thereof, so as to form a liquid metal hydride fuel solution;
providing a predetermined amount of liquid reactant comprising predominantly water; and
combining the liquid reactant with the liquid metal hydride fuel solution to create a reaction that generates hydrogen.
12. The method of claim 11 , wherein the liquid metal hydride fuel solution is pressurized before combining with the liquid reactant.
13. The method of claim 11 , wherein the liquid reactant is pressurized before contacting the liquid metal hydride fuel solution.
14. The method of claim 11 , wherein the metal hydride fuel comprises a metal borohydride.
15. The method of claim 14 , wherein the metal borohydride comprises sodium borohydride.