Abstract:
The invention is a hydrogen generator for supplying hydrogen to the anode of a fuel cell and electrons to the fuel cell electrical circuit. The hydrogen generator employs a consumable electrode comprising an alkali metal which is brought into contact with an aqueous solution of its hydroxide liberating hydrogen. The hydrogen generator operates as an alkaline cell electrode emersed in the electrolyte that is continuously being formed by the oxidation of the alkali metal within the electrode by its reaction in the electrolyte with the cycled water produced at the cathode of the fuel cell. The current flow within the hydrogen generator internal circuit of the reaction chamber is approximately equivalent to the feed rate of the consumable electrode into the electrolyte and the quantity of hydrogen formed is proportional to the equivalent weight of the water reacted.

Description:
BACKGROUND OF THE INVENTION 
     Basic hydroxides are formed with the liberation of hydrogen when the alkali metals lithium, sodium and potassium react with water. Two equivalent weights of each reactant are required to produce hydrogen in its diatomic form. 
     
       
         2Li+2H 2 O→2LiOH+H 2 ↑ 
       
     
     
       
         2Na+2H 2 O→2NaOH+H 2 ↑ 
       
     
     
       
         2K+2H 2 O→2KOH+H 2 ↑ 
       
     
     In the invention, the hydrogen produced in these reactions is used as a fuel source in a fuel cell and the liquid product of each reaction is employed as an electrolyte to produce electron flow between anode and cathode electrodes emersed in the alkaline solution—as in the instance of the Edison Cell which employs a potassium hydroxide solution. 
     Other elements such as the alkaline earths, magnesium and calcium, react with water to produce hydrogen but with greater difficulty, requiring the application of heat. In the detailed description in this application only the alkali metals are shown to be of practical interest and the discussion will be centered upon the use of sodium because of its greater abundance in nature. 
     The invention is a consumable electrode comprised of alkali metal particles in a dispersed phase within an inert heavy liquid medium that is applied by roller, or by other means, to the center surfaces of an inert flexible tape. A cover tape is then placed on top of the first tape containing the dispersion and both tapes are sealed together at their contacting edges forming a consumable electrode, hereinafter called the electrode. The finished electrode is then wound upon a spool in a dispensing cartridge or folded in layered form within a magazine dispenser. In operation, the tensile load on the electrode in the rolled package is nearly constant during its transit through the electrolyte in the reaction chamber, whereas the tensile load in the layered package is dynamically intermittent and higher, but it has the advantage of more efficient utilization of packaging space. 
     In some designs, particular in the larger electrode construction, a drying agent such as diatomaceous earth or calcium or silica powders may be applied upon the dispersion surface to facilitate manufacture and to promote, by capillary action or surface adsorption, migration of water into the electrode when emersed in the electrolyte. Because of the high heat of reaction when greater quantities of the dispersion are employed an inner glass cloth tape is employed for higher tensile strength of the electrode and to facilitate in holding larger quantities of the metallic dispersion in place during the manufacturing process. 
     Sealing the lower tape containing the metallic dispersion with the cover tape together at their edges in this manner forms a flattened tubular structure with the alkali metal reactant within. Therefore it is easily seen by those skilled in the art that the consumable electrode described in the application can also be manufactured as a plastic tubular structure by filling it with the dispersion through hydraulic means using a pump or vacuum to induct the dispersion into the tube. The method of manufacturing the tubular construction of the electrode does not effect the proprietary nature of this application. 
     Present methods used by others to supply hydrogen to a fuel cell employ methane gas reformers or methanol reformers, and in other instances by high pressure storage bottles or by cryogenic storage at −450° F. The reforming methods require high temperatures necessary to crack the fuel molecule and strip off the hydrogen component leaving a carbon residue which must be disposed of. Pressure bottle or cryogenic storage of hydrogen raise concerns of leakage in home garages, where most household water heaters are located, or in indoor communal parking areas of hotels and apartment complexes where building fires may occur. In the invention described in this application hydrogen is not present until there is a demand for its generation and immediate usage. Hydrogen is generated directly from the water and no carbon residue is formed except that which is in the tape and dispersion medium and this is continually processed into the spent electrolyte. The water of the electrolyte comes from the fuel cell which facilitates its service during refueling. 
     The bonding strength of an alkali metal with the hydroxyl ion is much lower than that of its corresponding halide bond. For this reason the reduction of the fused hydroxyl salt of an alkali metal to its base metal is more economic than that of its halide salt. As an example, sodium hydroxide melts at 318.4° C. and sodium chloride melts at 800.4° C. It is evident that the production of metallic sodium by high temperature electrolyses is more economical from its hydroxide than from its halide salt. To reduce the cost of fuel cell operation by use of a consumable electrode it is prudent that the expended electrolyte, in the reaction cell of the invention to be described, be recovered for recycling during replacement of the consumable electrode cartridge during refueling. 
     SUMMARY OF THE INVENTION 
     The invention is an electrochemical method of supplying hydrogen and electrons to a fuel cell. The design uses a reactive sodium electrode, hereinafter called a consumable electrode. The consumable electrode is formed as a sodium dispersion that is applied by continuous roller application, or by other means, upon a tape, or by hydraulic induction into a tubing, both tape and tubing being sufficiently flexible such that they may be wound upon a spool for insertion in a dispensing cartridge that feeds the consumable electrode into a caustic electrolyte solution. The quantity of hydrogen and electron flow generated by this means is approximately proportional to the feed rate of the consumable electrode into the electrolyte and to the quantity of the dispersed sodium metal reacted. 
     The primary objective of the invention is to provide a method of hydrogen generation for use in automotive fuel cells and other types of mobile equipment. 
     It is another object of the invention to show a means of servicing the fuel cell with a new consumable electrode dispensing cartridge by quick-disconnect mechanism, replacing the expended cartridge at a fuel station. 
     It is yet another object of the invention to provide an additional supply of electrons to a storage battery or directly to the fuel cell by hydrolysis of the sodium within the consumable electrode with the water content of the electrolyte that produces a migration of charged ions moving between the poles of the cathode and anode of the consumable electrode cartridge. 
     It is still another object of the invention to show a means of scavenging the expended electrolyte for reclaiming its sodium content. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Drawings are presented which show the manufacture and method of using a consumable electrode in the production of hydrogen and electron flow to a fuel cell. 
     FIGS. 1 a,    1   b,  and  1   c,  are cross-sections of the three variations of construction of the consumable electrode. 
     FIG. 2 illustrates a preferred method of puncturing the consumable electrode during continuous operation from a spool. 
     FIG. 3 illustrates the method of reacting the punctured consumable electrode in a vessel filled with electrolyte. 
     FIG. 4 illustrates an alternate method of packaging the consumable electrode. 
     FIG. 5 is an illustration of a consumable electrode cartridge placed in a reaction chamber and the interface connections necessary to service a fuel cell. 
     FIG. 6 is an illustration of consumable electrode package for insertion into a fuel cell hydrogen and electrical flow circuits. 
     FIG. 7 is a yoke for mounting the consumable electrode in a cartridge container. 
     FIG. 8 illustrates the method of sealing across the width of the consumable electrode at regularly spaced intervals. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention is a consumable electrode that is to be used for the production of hydrogen flow to the anode of a fuel cell with the simultaneous generation of electron flow to the fuel cell electrical circuit. In the description of the consumable electrode construction only the alkali metals are of practical interest and the discussion of their typical application in the invention will be centered upon the use of sodium for the purpose of clarity, and because of the greater abundance of sodium in nature making it more economically significant in this application. 
     A sodium dispersion in a heavy base mineral oil or other neutral medium is prepared by heating the metal above its melting point (207.5° F.) and rapidly mixing it in the medium. A suspending agent, such as oleic acid in trace amount, is added during the mixing to keep the metal particulate in the dispersed phase while it is being further processed. The sodium dispersion produced is hereinafter referred to as the dispersion. 
     The prepared dispersion is applied to the metalized surface of a plastic tape by continuous roller application which places the dispersion principally in the center area of the tape leaving the outer edges free of the dispersion material. A second tape, hereinafter called the cover tape, of equal width is placed over the tape containing the dispersion and both tapes are sealed together at their edges to prevent air contact with the dispersion during storage. 
     Three variations of the design of the consumable electrode are claimed and the cross-section of each variation are presented in FIGS. 1 a,    1   b,  and  1   c.  The cross-sectional thicknesses of the elements of their construction shown in FIGS. 1 a,    1   b,  and  1   c  are presented in exaggerated scale for clarity. 
     Referring to FIG. 1 a  of drawing sheet  1 . In FIG. 1 a  the consumable electrode is comprised of a dispersion  1  that is applied to the center area of tape  2 . A cover tape  3  is placed upon the said dispersion  1 . Tape  2  and cover tape  3  are sealed together at their contacting edges  4  on each side hermetically sealing the dispersion  1  within. Tape  2  and tape  3  form the outer casing of the consumable electrode and are hereinafter called the carrier insulation. 
     Referring to FIG. 1 b.  The consumable electrode of FIG. 1 b  comprises the same elements of FIG. 1 a,  dispersion  1 , tape  2 , and cover tape  3 . Tape  2  is metalized on the surface  5  that holds dispersion  1  for more effective electrical conduction. 
     Referring to FIG. 1 c.  The consumable electrode of FIG. 1 c  comprises the same elements as FIG. 1 b.  A glass-cloth tape  6  of lesser width than tape  2  and cover tape  3  is placed upon the metalized surface  5  of tape  2  before the application of dispersion  1 . Glass-cloth tape  6  helps to hold dispersion  1  upon metallic surface  5  when dispersion  1  is applied in greater quantities. Glass-cloth  6  also increases the tensile strength of the consumable electrode at higher operating temperatures when dispersion  1  is thicker. 
     Referring now to FIG. 2 of sheet  1  of the drawings which is a perspective view of consumable electrode  7  that is wound upon spool  8  which passes over guide roller  9  and is pulled under pin roller  10 . A plurality of needle sharp pins  11  are fixedly attached to the surface of pin roller  10  producing puncture holes  12  perforating both sides of the hermetically sealed carrier insulation exposing dispersion  1  within. 
     Referring now to FIG. 3 of sheet  1  of the drawings which shows a means of submerging consumable electrode  7  into an electrolyte  13  within reaction vessel  14  and the recovery of the expended carrier insulation of the consumable electrode  7  that passes under electrolyte spool  15  and over guide roller  16  to rewind spool  17  that is turned by gear motor  18 . The multiple puncture holes  12  perforate the carrier insulation of consumable electrode  7  impermeable tape membranes on each side exposing hermetically sealed dispersion  1  within to the gradual diffusion of the water content of electrolyte  13  into dispersion  1 . In the reaction of the alkali metal of dispersion  1  with the water content of the electrolyte  13  that also contains the cycled water of the fuel cell, hydrogen gas is liberated and the corresponding metal hydroxide is formed as previously shown above. An electrical potential is also produced within the electrolyte  13  between the rotating electrode  19  within spool  8  and electrolyte electrode  22 . Conduction of the current flow generated is carried in the external circuit through electrical brush  20  in rotative contact with rotating electrode  19  that is in electrical contact with conductor  21  and by conductor  23  in contact with electrolyte electrode  22 . Said conductors  21  and  23  are electrically connected to the corresponding terminals of the fuel cell. 
     Referring now to FIG. 4 of sheet  1  of the drawings which illustrates a different method of packaging the consumable electrode  7 . In FIG. 4 the consumable electrode  7  is shown packaged in folded layers. This method is preferred for consumable electrodes having a thicker cross-section that cannot be easily rolled upon a spool. In the folded packaging the rotating electrode  19  and brush  20  are replaced with stationary electrode  24 . All of the remaining numbered elements of FIG. 4 are the same as those shown in FIG.  3  and serve the same purpose and therefore the elements of each figure are the same. In operation the tensile load on the consumable electrode in the rolled package as shown in FIG. 3 is nearly constant, whereas the tensile load in the layered package is subject to higher dynamic force and is intermittent but it has the advantage of more effective utilization of packaging space. 
     Turning now to FIG. 5 of sheet  2  of the drawings. FIG. 5 illustrates the manner of mounting spool  8  holding the consumable electrode  7  of FIG. 3 into dispensing cartridge case  25 . The rotating electrode  19  of FIG. 3 is shown in FIG. 5 as being mounted on axle  26  of mounting yoke  27 . Brush  20  and conductor  21  of FIG. 3, not shown in FIG. 5, conducts current flow from electrode  19  to service pin  28  which interfaces with the fuel cell electrical circuit. 
     The consumable electrode  7  wound on spool  8  is mounted on axle  26  of mounting yoke  27  and is passed over guide roller  9 , and under pin roller  10  and electrolyte roller  15  and upward over guide roller  16  and fixedly attached to rewind spool  17  that is rotatively mounted on axle  29  of said mounting yoke  27 . The mounting yoke  27  is shown in perspective view in FIG. 7 of sheet  3  of the drawings. After mounting the consumable electrode  7  on mounting yoke  27  the said mounting yoke is fastened to dispensing cartridge case  25  by bolts  49  and the two halves of the cartridge case are hermetically sealed together at their flanging surfaces. Storage plug  50  inserted in hydrogen tube  35  and storage cap  51  is placed over the lower flanged end to cover the roller pin  10  and electrolyte roller  15  for storage is shown in FIG. 6 of sheet  3  of the drawings. 
     Returning now to FIG.  5 . The dispensing cartridge case  25  that is loaded with consumable electrode  7  as described above is inserted into electrically insulated reaction chamber  30  holding electrolyte  13 . Electrolyte  13  fills the said reaction chamber to its operating level of weir openings  31 . The electrolyte  13  is produced from water in holding tank  32  supplied to the said reaction chamber  30  through pipe  33 . The reaction of the water from pipe  33  in contact with dispersion  1  through the puncture holes  13  of the carrier insulation of consumable electrode  7  form the metal hydroxide and liberate hydrogen. The liberated hydrogen passes through holes  34  of hydrogen tube  35  that interfaces at connector fitting  36  with the fuel cell. Water formed in the fuel cell enters holding tank  32  through water tube  37  interface connector fitting  38 . Make up water is supplied to holding tank  32  through fill pipe  39 . Water is pumped to reaction chamber  30  by submerged pump  40 . Water is drained from holding tank  32  through valve  41 . Electrolyte electrode  22  of FIG. 3, but not shown in FIG. 5, is electrically connected by conductor  23  to service pin  47  which interfaces with the corresponding electrical circuit of the fuel cell. Utility connector  48  connects the various electrical equipment, valves, pumps, and sensors that operate the system, to the electrical supply interface. 
     Excess electrolyte in reaction chamber  30  passes from reaction chamber  30  through weir  31  spilling into baffle chamber  42 . The excess electrolyte held in baffle chamber  42  spills out over weir  43  into expended electrolyte reservoir  44  which is emptied through normally closed solenoid valve  45  for reclaiming its metal content. 
     Referring now to FIG. 8 of sheet  3  of the drawings. In FIG.  8 . the consumable electrode  7  is pinched together and sealed  46  at regular intervals across its width. Sealing at points  46  limits the amount of hydrogen blow-back into unreacted dispersion  1  within the consumable electrode  7 . During periods when the system is not in operation the seal  46  prevents migration and diffusion of water vapor into the unreacted portion of dispersion  1  within consumable electrode  7 .