EP1554768A2 - Fuel cell system and method for producing electrical energy - Google Patents
Fuel cell system and method for producing electrical energyInfo
- Publication number
- EP1554768A2 EP1554768A2 EP03809028A EP03809028A EP1554768A2 EP 1554768 A2 EP1554768 A2 EP 1554768A2 EP 03809028 A EP03809028 A EP 03809028A EP 03809028 A EP03809028 A EP 03809028A EP 1554768 A2 EP1554768 A2 EP 1554768A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- fuel cell
- hydrogen
- fuel
- water
- cell system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000000446 fuel Substances 0.000 title claims abstract description 246
- 238000004519 manufacturing process Methods 0.000 title abstract description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 103
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 98
- 239000001257 hydrogen Substances 0.000 claims abstract description 91
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 91
- 239000000126 substance Substances 0.000 claims abstract description 60
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000001301 oxygen Substances 0.000 claims abstract description 27
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 27
- 239000007795 chemical reaction product Substances 0.000 claims abstract description 6
- 150000004678 hydrides Chemical class 0.000 claims description 54
- 238000006243 chemical reaction Methods 0.000 claims description 29
- 238000000034 method Methods 0.000 claims description 14
- 239000007789 gas Substances 0.000 claims description 11
- 239000012279 sodium borohydride Substances 0.000 claims description 11
- 229910000033 sodium borohydride Inorganic materials 0.000 claims description 11
- 239000010409 thin film Substances 0.000 claims description 6
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 5
- 239000012448 Lithium borohydride Substances 0.000 claims description 5
- 229910001882 dioxygen Inorganic materials 0.000 claims description 5
- -1 CaH2 Substances 0.000 claims description 4
- 238000013022 venting Methods 0.000 claims description 4
- 229910010084 LiAlH4 Inorganic materials 0.000 claims description 3
- 239000000654 additive Substances 0.000 claims description 3
- 239000012280 lithium aluminium hydride Substances 0.000 claims description 3
- 229910010082 LiAlH Inorganic materials 0.000 claims 1
- 150000002431 hydrogen Chemical class 0.000 abstract description 9
- 239000006227 byproduct Substances 0.000 abstract description 5
- 238000010248 power generation Methods 0.000 abstract description 3
- 230000010354 integration Effects 0.000 abstract description 2
- 239000007788 liquid Substances 0.000 abstract description 2
- 238000011038 discontinuous diafiltration by volume reduction Methods 0.000 abstract 1
- 230000008901 benefit Effects 0.000 description 12
- 239000000376 reactant Substances 0.000 description 11
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000007787 solid Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 239000012528 membrane Substances 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 229910015444 B(OH)3 Inorganic materials 0.000 description 4
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 4
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000003466 anti-cipated effect Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000035515 penetration Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- 229910021502 aluminium hydroxide Inorganic materials 0.000 description 1
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 239000008246 gaseous mixture Substances 0.000 description 1
- 229910001679 gibbsite Inorganic materials 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 150000004681 metal hydrides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 239000012265 solid product Substances 0.000 description 1
- 239000002915 spent fuel radioactive waste Substances 0.000 description 1
- 230000000153 supplemental effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
- H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
- H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
- H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
- H01M8/04156—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying with product water removal
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
- H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
- H01M8/065—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants by dissolution of metals or alloys; by dehydriding metallic substances
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Definitions
- the present invention relates generally to fuel cells, and more particularly, to fuel cells that consume gaseous hydrogen-containing fuels and produce electrical energy and water.
- a fuel cell typically generates water in the normal course of power generation using oxygen in the air to electrochemically combine with hydrogen gas to produce electrical energy by well-known electrochemical principles.
- Advantageous fuel cells for energy conversion are described in my U.S. Patent Nos. 4,863,813; Re34,248; 4,988,582 and 5,094,928.
- a hydrogen-containing material at room temperature such as a gaseous mixture of hydrogen and oxygen, is directly converted to direct-current electrical energy and the only reaction product is water.
- a submicrometer-thick gas permeable ionically conducting electrolytic membrane made of pseudoboehmite is deposited on an electrode that comprises a platinized impermeable substrate.
- a layer of platinum, for example, is deposited on the top surface of the membrane to form the other electrode of the fuel cell, which electrode is porous enough to allow the gas mixture to pass into the membrane.
- a fuel cell provides useful current at an output voltage as large as about one volt. While the voltage and current provided by the basic fuel cell are adequate for many applications of practical interest, I recognized that it would be desirable to devise a compact source of hydrogen for this and other fuel cells especially for portable electronic device applications, such as laptop computers and mobile phones.
- a suitable combination of a fuel cell with a lightweight, low volume source of hydrogen could provide an improved source of power for portable electronic applications compared with batteries.
- a chemical hydride material with a high hydrogen content, react with water to yield hydrogen.
- Watt-hours per kilogram or Watt-hours per liter are examples of the specific energy of a fuel for a fuel cell.
- a fuel cell with its fuel termed a fuel cell system, would benefit from the use of a high specific energy fuel which would thereby reduce the carrying weight and volume of the fuel cell system.
- the present invention implements operation of a fuel cell with hydrogen fuel derived from the reaction of a chemical fuel, such as a chemical hydride, with the by-product water from the fuel cell.
- Integration of this fueling means with a suitable fuel cell constitutes a device, termed a fuel cell system, which is characterized in that it only requires an external supply of oxygen or air and has a higher specific energy density than a fuel cell system that requires a separate or additional source of water.
- the present invention improves the performance, control and safety of a fuel cell system in which a fuel cell is coupled to the fuel supply consistent with the principles of the invention.
- the improved performance of the device is characterized by a higher specific energy content, as measured by weight and volume. This improvement is achieved by elimination of the need to include additional water for reaction with a chemical hydride to produce hydrogen.
- An additional advantage of the present invention is that it controls the rate of hydrogen generation by controlling the water supply to the chemical hydride.
- the water supply available for reaction with the chemical fuel containing hydrogen is controlled by the electrical energy demanded.
- a fuel cell that produces water vapor during the course of its operation is coupled to a suitable chemical hydride, which is defined as a hydrogen-containing fuel that reacts with water vapor to produce hydrogen gas under the same ambient conditions as the fuel cell and does not need a separate source of water other than supplied by the fuel cell.
- the water vapor from the fuel cell exhaust is directed towards a container containing the suitable chemical hydride material where it reacts to form hydrogen, which is then delivered to the anode of a fuel cell to sustain the electrical energy production.
- Typical fuel cells produce water at the cathode or positive electrode which is mixed with air and so the product after reaction of this typical fuel cell exhaust with a chemical hydride would contain both hydrogen and air.
- the fuel is required to be mostly uncontaminated with air. Therefore if the fuel cell requires hydrogen mostly unmixed with air at its anode or negative electrode, an additional means to separate the water vapor from the air or the hydrogen from the air would be advantageous, so that only hydrogen mostly unmixed with air is supplied to the fuel cell anode.
- a fuel cell which not only produces water vapor but also requires a mixture of air and hydrogen to generate electrical energy, would especially benefit from the present invention since no separation of water from air or hydrogen from air would be required to operate such a fuel cell.
- Examples of such a fuel cell are described in my U.S. Patent Nos. 4,863,813; Re34,248; 4,988,582 and 5,094,928.
- This fuel cell combined with the present invention would constitute a preferred embodiment.
- Another fuel cell that would advantageously benefit from the present invention would be a fuel cell that produces water unmixed with air, for instance a fuel cell which produces water at the anode, or negative electrode side of the cell, where it is accompanied by mostly hydrogen, an example being the solid oxide fuel cell.
- the supply of water in the present invention is regulated by the electrical energy demand.
- the chemical fuel such as a chemical hydride is preferably chosen to require the same amount of reactant water as the fuel cell produces to sustain the fuel cell operation. This then prevents excessive and wasteful production of hydrogen and thereby acts as a control, which is advantageous to both conservation of the remaining chemical hydride material and to safety.
- the chemical hydride is also preferably selected on the basis that the supply of water by the fuel cell is sufficient to react all of the chemical hydride.
- the rate of production of hydrogen needed for use in a fuel cell is exactly balanced by the amount of water it produces when using a preferable chemical hydride.
- the electrical energy demand is increased, more current is produced accompanied by more water production, which on reaction with the chemical hydride leads to more hydrogen production to sustain the higher electrical energy demand.
- the demand for electrical energy is reduced to zero, the amount of water produced is correspondingly reduced to zero and as a consequence, the amount of hydrogen is also reduced to zero, which provides a safe method of storing and transporting hydrogen.
- the present invention advantageously provides a means of efficient and safe control of the amount of hydrogen produced.
- Another advantage of the present invention would be the use of a solid hydrogen-containing fuel that effectively absorbs product water from the fuel cell, thereby avoiding wetness and flooding in the vicinity of the outlet from an operating fuel cell.
- Several inorganic chemical hydrides react with water vapor to give hydrogen and also produce a solid product, which is a beneficial method of "water management" in the present invention.
- Further attendant benefits characterize the present invention since it provides a means of measuring the remaining energy content of the fuel.
- the production of hydrogen may be accompanied by a weight and volume gain within the chemical hydride container. Such physical changes could be monitored by simple gravimetric or volumetric means to provide a measure of the extent of reaction undergone by the chemical hydride and therefore the remaining energy content of the system.
- Fig. 1 is a simplified diagrammatic representation of a fuel cell system according to the principles of the present invention.
- Fig. 2 is an explanatory diagram showing the reactions that take place using air as the source of oxygen during operation of the fuel cell system shown in Fig. 1.
- the fuel cell system comprises a hydrogen-containing fuel 1 such as, for example, a NaBH 4 chemical hydride fuel, housed within a fuel container 2.
- the fuel container 2 has an inlet 3 for admitting water principally in the form of water vapor into the container 2 for reaction with the hydrogen-containing fuel 1 to produce hydrogen gas which exits the container 1 through an outlet 4.
- a fuel cell enclosure 5 has disposed therein a fuel cell 6 which may, for example, be of the type described in my U.S. Patent Nos. 4,863,813; Re43,248; 4,988,582 and 5,094,928, the entire disclosures of which constitute part of the disclosure of the present application and are hereby incorporated by reference herein.
- An example of one such fuel cell 6 is shown diagrammatically in Fig. 1 and comprises a mixed-gas fuel cell having an impermeable substrate 18, an impermeable or permeable catalytic electrode 17, a permeable ion- conducting electron-insulating electrolytic membrane 16 (referred to as a solid electrolyte body in my earlier patents) and a permeable catalytic electrode 15.
- the catalytic electrodes 15 and 17 and the membrane 16 are typically thin in accordance with the prior said disclosures from which the term thin film fuel cell used in conjunction with these disclosures derives.
- the substrate 18 is typically relatively thick when compared with the thin film fuel cell since it acts as a mechanical support for the thin film fuel cell.
- Substrate 18 may usefully also be electronically conductive.
- the fuel cell 6 is provided with a pair of lead wires 6a, 6b for extracting the electrical energy produced by the fuel cell, and the lead wires 6a, 6b are connected to fuel cell electrodes in a manner known in the art.
- the fuel cell enclosure 5 is provided with an oxygen inlet 7 for introducing oxygen into the enclosure, a hydrogen inlet 8 for introducing hydrogen gas into the enclosure, and a water outlet 9 for discharging water from the enclosure.
- An inlet valve 10 is preferably provided at the oxygen inlet 7 for controlling the inflow of oxygen gas.
- the outlet 4 of the fuel container 2 is directly connected to the hydrogen inlet 8 of the enclosure 5 by a conduit 11.
- the interior of the fuel container 2 communicates with the interior of the fuel cell enclosure 5 so that hydrogen gas produced by the fuel 1 discharges through the outlet 4 and is directed through the conduit 11 and the hydrogen inlet 8 into the fuel cell enclosure 5.
- another conduit 12 communicates the water outlet 9 of the fuel cell enclosure 5 with the inlet 3 of the fuel container 2. This enables water produced during operation of the fuel cell 6 to be admitted into the fuel container 2 for reaction with the hydrogen-containing fuel 1.
- a venting valve 14 may be provided along the conduit 12.
- oxygen or air is admitted through the inlet valve 10 (which is in the open position) and the oxygen inlet 7 into the fuel cell enclosure 5 and mixes with hydrogen admitted through the hydrogen inlet 8 to form the gas mixture needed for the fuel cell 6 to generate electrical energy which passes along the lead wires 6a, 6b attached to the fuel cell electrodes.
- a corresponding amount of water vapor is generated by the fuel cell 6 and is discharged from the fuel cell enclosure 5 through the water outlet 9 and passes through the conduit 12 to the hydrogen-containing fuel 1 via the inlet 3.
- the water vapor reacts with the hydrogen-containing fuel 1 in the fuel container 2, and results in more hydrogen being passed to the fuel cell 6 to sustain the electrical energy generation.
- gases not reacted by the fuel cell 6 including unreacted oxygen and hydrogen may pass through the outlet 9 and then pass unreacted through the fuel 1, container 2, outlet 4 conduit 11 and inlet 8 to the enclosure 5.
- gases not reacted by the fuel cell 6 including unreacted oxygen and hydrogen may pass through the outlet 9 and then pass unreacted through the fuel 1, container 2, outlet 4 conduit 11 and inlet 8 to the enclosure 5.
- nitrogen will also pass unreacted through the elements of the fuel cell system shown in Fig.l and further illustrated in Fig. 2. Such air will subsequently become oxygen depleted as a result of normal fuel cell operation.
- oxygen or air may be forced into the fuel cell enclosure 5 through the oxygen inlet 7 with the inlet valve 10 open. This may be achieved by using some of the electrical energy produced by the fuel cell 6.
- the venting valve 14 may need to be incorporated to allow oxygen-depleted air from the fuel cell container 2 to be removed and replaced by oxygen-rich air through the oxygen inlet 7.
- Variations of the arrangement in Fig. 1 might include removal of the valves 10 and 14 and removal of the outlet 4, the inlet 8 and the conduits 11 and 12, so that the fuel cell enclosure 5 is directly connected to the fuel container 2.
- One or more openings (such as the outlet 9) provided in the fuel cell enclosure 5 would be aligned with similar openings (such as the inlet 3) provided in the fuel container 2 so that air diffusing through the oxygen inlet 7 would mix with hydrogen diffusing from the fuel container 2 to provide the mixed gas environment required for power generation by the fuel cell 6 and water vapor diffusing from the fuel cell enclosure 5 would enter the fuel container 2 for reaction with the hydrogen-containing fuel 1.
- This variation of arrangement would allow a simpler design and would generate lower levels of power and be suitable for low powered portable equipment such as a cellphone. Higher levels of power required during cellphone transmission would be powered by a small battery, kept constantly charged by the low power fuel cell system.
- the fuel container 2 is removably connected in the fuel cell system so that it can be removed and replaced by a new fuel container.
- any suitable removable connection may be employed, such as threaded connections or bolted flange connections, to removably connect the inlet 3 and the outlet 4 of the fuel container 2 to the conduits 11 and 12.
- the fuel container 2 would be removably connected directly to the fuel cell enclosure 5 so that the outlet 9 of the fuel cell enclosure 5 communicates directly with the inlet 3 of the fuel container 2.
- a plurality of aligned outlets 9 and inlets 3 could be provided in the enclosure 5 and container 2, respectively.
- the conduit 12 could be retained, in which case only the inlet 3 of the fuel container 2 need be removably connected to the conduit 12. In this manner, a spent fuel container 2 may be removed and replaced with a fresh fuel container.
- the overall reaction shows that the fuel cell system shown in Fig. 1 produces electrical energy from only one external reactant (oxygen) , which is readily available in air, and that no excess hydrogen is produced other than is needed internally for electrical energy production.
- the reaction also shows that the amount of water produced by the fuel cell is sufficient to react all of the chemical hydride material.
- An internal cycle of water and hydrogen production is directly controlled and regulated by the external demand for electrical energy which makes the system inherently safe. This cycle may be characterized as follows: For a given amount of electrical energy produced, the rate of production of hydrogen needed for use in a fuel cell is exactly balanced by the amount of water it produces when using suitable chemical hydrides.
- a fuel cell capable of producing electrical power on exposure to a mixture of air and 2-4% hydrogen would particularly benefit from the present invention since the carrying capacity of air for water vapor is in the same range, namely 2-4% for the temperature range 20-30 °C.
- This particular benefit arises because in the exemplary reactions shown above, reaction of a given number of water molecules with the chemical hydride produces the same number of molecules of hydrogen thus providing a natural control of the amount of hydrogen generated to the range 2-4% which is generally considered to be a safe level of hydrogen in air, which would be especially beneficial for use in the portable electronic device applications envisaged such as mobile phones and laptop computers.
- the supply of water as vapor is an advantageous means to utilize most efficiently the chemical hydride fuel.
- the inlet valve 10 prevents uncontrolled access of air or oxygen to the fuel cell system when not in use as shown in Fig. 1.
- the inlet valve 10 would typically comprise a shut-off valve, mechanically or electrically activated when the fuel cell 6 was no longer delivering power.
- the venting valve 14 would also be closed when the fuel cell 6 was not operating to produce electrical power.
- the present invention couples the fuel cell to the chemical fuel by a system of inlets and outlets which obviate the need for supplying external water to react with the chemical hydride.
- the fuel cell system of the present invention thereby is lighter in weight and smaller in volume by the amount of water that is not needed, which for sodium borohydride, amounts to a weight and volume savings of approximately two thirds. This is clearly advantageous for portable applications.
- the specific energy density based on the hydrogen content of sodium borohydride alone (without including the volume or weight of reactant water) is approximately 6300 Watt-hours per liter and 5900 Watt-hours per kilogram. Other chemical hydrides would provide even higher energy densities if used in accordance with the present invention.
- LiBH 4 + 4H 2 0 > 4H 2 + LiOH.B(OH) 3
- LiAlH 4 + 4H 2 0 > 4H 2 + LiOH.Al(OH) 3
- suitable fuels for beneficial use in the present invention. Their selection will also depend upon factors including their specific energy density, rate of reaction with water vapor, completeness of reaction with water vapor, temperature, etc. Substantially higher specific energy densities are available by using a Li-based hydride such as LiBH 4 , which has an energy density of approximately 10,000 Watt-hours per liter and per kilogram. If used in the present invention, this specific energy is much higher than popular fuels for fuel cells such as methanol and relatively heavy metal hydrides which adsorb and desorb hydrogen gas as opposed to chemical hydride fuels used in the present invention which react with water to produce hydrogen gas.
- Li-based hydride such as LiBH 4
- Advantageous embodiments of the present invention would include means to utilize as much of the chemical hydride fuel as possible by the fuel cell supplied water vapor.
- the water supplied from the fuel cell to the chemical hydride if in a vaporized state, would assist penetration into a solid chemical hydride mass to achieve a more uniform extent of reaction of the available solid chemical hydride (high utilization) than if the water were in a liquid state.
- water as vapor reduces the onset of vapor-pathway blockage of the solid chemical hydride particulate mass, which would otherwise reduce system energy density by precluding further water access to the inner particles of chemical hydride.
- a fusible polymer to the chemical hydride particles may be beneficial for safety by selecting a polymer which would melt and spread over the remaining chemical hydride fuel if the temperature rose to an unacceptable level, which would present a barrier to further reaction with incoming water vapor thereby reducing the rate of reaction of the water vapor with the chemical hydride fuel .
- All fuel cells producing electrical energy from hydrogen and oxygen generate water which at ambient temperature can condense and accumulate at their electrodes and so reduce electrode performance by obstructing the flow of reactant gas to the catalytic surfaces of the electrode. This is commonly prevented by increasing airflow to displace the water.
- the present invention removes water vapor without having to increase airflow and internally reduces water condensate formation by acting as a 'drying' agent in close proximity to the fuel cell. This is especially advantageous in fuel cell applications near to people and equipment, which are susceptible to build up of moisture.
- the present invention anticipates the removal of both the spent chemical hydride fuel with chemically reacted water by mechanical means. Removal of the fuel container 2 in Fig. 1 and replacement by a container with unreacted chemical hydride can be designed to be simple and efficient. Disposal of the spent sodium borohydride which is solid borax is not anticipated to be problematic for this invention.
- the invention is not so limited and can be carried out using generally any type of fuel cell that consumes hydrogen and produces water as a reaction product.
- the present invention can be practiced using fuel cells that require different electrochemical reactants or different electrochemical reactant concentrations at the cathode and anode electrodes provided that the fuel cells consume hydrogen and produce water as a reaction product.
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Fuel Cell (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US273280 | 2002-10-17 | ||
US10/273,280 US6864002B1 (en) | 2001-10-19 | 2002-10-17 | Fuel cell system and method for producing electrical energy |
PCT/US2003/032614 WO2004036667A2 (en) | 2002-10-17 | 2003-10-15 | Fuel cell system and method for producing electrical energy |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1554768A2 true EP1554768A2 (en) | 2005-07-20 |
Family
ID=32106452
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03809028A Withdrawn EP1554768A2 (en) | 2002-10-17 | 2003-10-15 | Fuel cell system and method for producing electrical energy |
Country Status (10)
Country | Link |
---|---|
EP (1) | EP1554768A2 (en) |
JP (1) | JP2006503414A (en) |
KR (1) | KR20050052533A (en) |
CN (1) | CN1706064A (en) |
AU (1) | AU2003301472A1 (en) |
BR (1) | BR0315399A (en) |
CA (1) | CA2501735A1 (en) |
ES (1) | ES2299324B1 (en) |
FI (1) | FI20050389A (en) |
WO (1) | WO2004036667A2 (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8048576B2 (en) | 2005-07-12 | 2011-11-01 | Honeywell International Inc. | Power generator shut-off valve |
US7901816B2 (en) * | 2005-11-09 | 2011-03-08 | Honeywell International Inc. | Water reclamation in a micropower generator |
US7727655B2 (en) * | 2005-10-25 | 2010-06-01 | Honeywell International Inc. | Fuel cell stack having catalyst coated proton exchange member |
US7811690B2 (en) * | 2005-10-25 | 2010-10-12 | Honeywell International Inc. | Proton exchange membrane fuel cell |
US7976971B2 (en) * | 2006-05-11 | 2011-07-12 | Honeywell International Inc. | Power generator with a pneumatic slide valve |
JP2009099491A (en) * | 2007-10-19 | 2009-05-07 | Sharp Corp | Fuel cell system and electronic equipment |
JP4816816B2 (en) | 2009-09-09 | 2011-11-16 | コニカミノルタホールディングス株式会社 | Fuel cell |
WO2011089811A1 (en) * | 2010-01-22 | 2011-07-28 | コニカミノルタホールディングス株式会社 | Fuel cell system |
JP5509895B2 (en) * | 2010-02-05 | 2014-06-04 | コニカミノルタ株式会社 | Fuel cell |
US20150064584A1 (en) * | 2012-03-28 | 2015-03-05 | Konica Minolta, Inc. | Secondary Battery Fuel Cell System |
CN110001674A (en) * | 2019-04-08 | 2019-07-12 | 小飞象汽车技术(苏州)有限公司 | A kind of high-speed rail dynamical system based on solid hydrogen |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH692879A5 (en) * | 1997-12-18 | 2002-11-29 | Dch Technology Inc | Apparatus for converting energy using fuel cells with integrated hydrogen gas generation. |
US6368735B1 (en) * | 1999-10-19 | 2002-04-09 | Ford Global Technologies, Inc. | Fuel cell power generation system and method for powering an electric vehicle |
-
2003
- 2003-10-15 ES ES200550024A patent/ES2299324B1/en not_active Withdrawn - After Issue
- 2003-10-15 WO PCT/US2003/032614 patent/WO2004036667A2/en not_active Application Discontinuation
- 2003-10-15 AU AU2003301472A patent/AU2003301472A1/en not_active Abandoned
- 2003-10-15 CN CNA2003801016577A patent/CN1706064A/en active Pending
- 2003-10-15 BR BR0315399-1A patent/BR0315399A/en not_active IP Right Cessation
- 2003-10-15 CA CA002501735A patent/CA2501735A1/en not_active Abandoned
- 2003-10-15 KR KR1020057006327A patent/KR20050052533A/en not_active Application Discontinuation
- 2003-10-15 JP JP2004545297A patent/JP2006503414A/en active Pending
- 2003-10-15 EP EP03809028A patent/EP1554768A2/en not_active Withdrawn
-
2005
- 2005-04-15 FI FI20050389A patent/FI20050389A/en not_active IP Right Cessation
Non-Patent Citations (1)
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See references of WO2004036667A2 * |
Also Published As
Publication number | Publication date |
---|---|
ES2299324A1 (en) | 2008-05-16 |
CN1706064A (en) | 2005-12-07 |
JP2006503414A (en) | 2006-01-26 |
AU2003301472A1 (en) | 2004-05-04 |
WO2004036667A3 (en) | 2004-06-24 |
KR20050052533A (en) | 2005-06-02 |
CA2501735A1 (en) | 2004-04-29 |
FI20050389A (en) | 2005-04-15 |
WO2004036667A2 (en) | 2004-04-29 |
ES2299324B1 (en) | 2009-05-08 |
BR0315399A (en) | 2005-08-23 |
AU2003301472A8 (en) | 2004-05-04 |
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