HYDROGEN STORAGE VESSEL WITH METAL-BASED HYDROGEN STORAGE FIBERS
FIELD OF THE INVENTION
[0001] The present invention relates to metal-based hydrogen storage fibers that are capable of selectively absorbing and desorbing or releasing hydrogen gas, as well as hydrogen storage vessels including the fibers, which preferably are arranged in the form of a fabric. The fabric is a porous structure having a large surface area well suited for hydrogen storage and transportation. The invention advantageously provides hydrogen storage system possessing attractive attributes. Hydrogen storage in metal hydride fibers provides a compact and safe method for hydrogen storage, wherein the hydrogen molecules in the gas phase can be absorbed physically on the surface of the fibers forming a metal hydride and also dissociate into individual hydrogen atoms which can further defuse into the bulk fiber and occupy sites of the metal hydride fiber matrix.
BACKGROUND OF THE INVENTION
[0002] Alternative fuel sources are sought throughout the world to replace fossil fuels as primary energy sources, especially for the transportation field.
[0003] While electric batteries provide one means to replace fossil fuels, drawbacks exist. For example, most electric batteries alone are not powerful enough to move heavy trucks, trains and airplanes. In addition, long charging times inhibit adoption of electric battery technology. For commercial vehicles, long charging times mean reduced productivity since the vehicles are idle during charging.
[0004] Hydrogen is another alternative fuel that can be produced using solar power and wind power which can be stored and transported. Hydrogen generated through the use of green energy such as solar power, wind power, wave energy or hydroelectricity is considered green hydrogen.
[0005] Green hydrogen is the ultimate renewable and clean energy for the hydrogen economy. For storage of hydrogen, there are multiple solutions for stationary storage that can be installed and used by power plants, utility microgrids, manufacturing facilities, and even households. However, for cars, trucks, trailers, airplanes, etc., storing and transporting hydrogen is still the most challenging task. Hydrogen is light and it is extremely difficult to store a sufficient amount of hydrogen in a tank that fits into movable vehicles. With liquid hydrogen, the energy density is somewhat improved, but it has to be maintained at extremely low temperatures below -252.8°C. This requires an advanced thermal management system and is very costly. Compressed hydrogen gas can be also used to power moving objects through hydrogen combustion engines or hydrogen fuel cells. However, the amount of hydrogen that can be stored in a tank or vessel is very limited even at extremely high pressure of 300-700 bars. Currently, there are commercial vehicles that run on hydrogen using compressed hydrogen gas. Due to its low energy density and high cost, it is not widely accepted for use in passenger vehicles, trucks, trains, and airplanes.
[0006] Metal hydrides have been studied in the past decades as hydrogen storage media extensively. Some transition metals are known to absorb/adsorb hydrogen under proper conditions such as high pressure to form metal hydrides. Metal hydrides can release hydrogen at higher temperatures or under reduced pressure. This process is reversible and metal hydrides can store more hydrogen than the other forms of hydrogen such as liquid hydrogen and compressed hydrogen gas. Recently GKN Hydrogen developed a solid state hydrogen storage system that uses blocks of metal hydrides as a storage media. This technology is fine for stationary storage, where space and weight are not limited, but not for hydrogen transportation since the metal hydride blocks are extremely heavy.
[0007] Past attempts of the use of metal hydrides have involved grinding metal hydrides into powders, for example through ball milling in order to increase the surface area of the metal hydrides which improves absorption and desorption kinetics. However, ball milling is a very time consuming and costly process. There are also safety concerns with metal hydride powders. In addition, the powder may agglomerate reducing its efficiency over time. The powders may also clog filters utilized in hydrogen storage tanks.
[0008] U.S. 4,310,601 relates to a metal hydride storage device with a hydrogenatable storage metal powder and with an encapsulation of non-hydrogenatable material receiving the storage metal powder; wherein the storage metal powder includes a substantially uniformly distributed addition of about 2 to 10% by weight of powder-shaped non-hydrogenatable material forming a matrix powder, contained in the encapsulation as form-rigid compressed or sintered body.
[0009] CN 104676239 relates to a metal hydride hydrogen storage device, which belongs to the technical field of hydrogen storage. The device is composed of a valve, a front cover, a gas path tube, a bottleneck connector, a clamping sleeve, a sealing gasket, a filter disc, a shell, two fans, a longitudinal heat transfer finned tube, a hydrogen storage container, a hydrogen storage material bed body, and a porous gas guide tube, wherein the bottleneck connector is connected with a hydrogen storage bottle body and the gas path tube by the sealing gasket and the clamping sleeve; the gas path tube is connected with the porous gas guide tube and the valve by the filter disc; the front cover and the two fans are arranged on the shell, and the longitudinal heat transfer finned tube and a hydrogen storage bottle are arranged in the shell; and the hydrogen storage material bed body and the porous gas guide tube are arranged in the hydrogen storage bottle body.
[0010] JP 2000191301 relates to a metal hydride reactor 10 that comprises an outer container 11 , an inner container 12 which is inserted into the outer container 11 , fins 13 which project in a direction intersecting with a central axis from the inner wall of the inner container 12 and extends in an axial direction, and a porous pipe 14 which is supported by the front ends of the fins 13, disposed along the container axis, wherein the container wall is permeable to the hydrogen but impermeable to metal hydrides and is end-sealed at one end. The metal hydride 15 is packed into the space enclosed by the inner container 12, the fins 13 and the porous pipe 14. Fiber material 16 is packed around the other end of the porous pipe 14 and the outer container 11 is drawn, by which the fiber material 16 is compressed. The connecting pipe 17 which is the flow passage for the hydrogen is connected to the end of the drawn outer container 11 .
[0011] U.S. 2021/0291267 relates to vehicle structural components and additive manufacturing methods for forming the components. The structural components incorporate hydrogen storage materials for use in conjunction with hydrogen fuel cells in electric-powered vehicles such as unmanned aerial vehicles. The hydrogen storage materials can be in the form of a 3D printed metal foam that includes a metal hydride and an inert structural metal. The material can exhibit a very low weight density able to store hydrogen in a low pressure solid-state form at a high energy density. The structural components that carry the hydrogen storage materials can be exchangeable components of a vehicle, and the vehicle can be refueled by merely exchanging an exhausted component for a replacement component that is fully charged with hydrogen.
[0012] Hydro Quebec has also developed metal hydride technology through the use of manganese hydride molecular sieve as a storage media for hydrogen. The manganese hydride is formed as nanoparticles with porous structures so hydrogen can be charged or discharged reportedly within a reasonable time period. However, the process for making such molecular sieves is quite time and energy intensive, and thus less practical in the real world.
[0013] Hydrogen fuel cells have been examined for use in powering the electric motors of vehicles. Hydrogen fuel cells can extend travel time between recharging as compared to electric motors powered with batteries, but still present significant issues. A major drawback to the wider utilization of hydrogen as a vehicle fuel remains the lack of acceptable hydrogen storage mediums. Conventionally, hydrogen has been stored in the gas phase under high pressure or in the liquid phase at extremely low temperatures. Unfortunately, high-pressure hydrogen storage vessels are bulky, heavy, and pose a safety concern, particularly if considered for use in vehicles, and low temperature liquid phase storage is even less feasible for use in hydrogen fuel cell powered vehicles or hydrogen combustion engine powered vehicles.
[0014] What is needed in the art are systems and methods that can be used to safely and efficiently store and release hydrogen to a hydrogen fuel cell or hydrogen combustion engine as may be used to power an electric vehicle. A low pressure vessel that can store and release hydrogen without the weight and bulk necessitated by a high pressure gas storage tank would be highly beneficial. The ability to quickly refuel the vehicle by quick and simple replacement of the hydrogen in the storage vessel would also be of great benefit in the art. SUMMARY OF THE INVENTION
[0015] In view of the above, the art still needs hydrogen storage vessels that overcome the disadvantages and drawbacks of the prior art. The problems of the prior art and others are solved by the present invention which provides metal-based hydrogen storage fibers capable of selectively absorbing and desorbing or releasing hydrogen gas, and hydrogen storage vessels including the same within the interior volume of the vessel.
[0016] In one embodiment of the present invention, a hydrogen storage vessel is provided having a plurality of metal-based hydrogen storage fibers disposed therein capable of absorbing hydrogen thereby forming metal hydrides. In a preferred embodiment, the fibers are provided in the form of a fabric, stacked or rolled nonwoven or woven fabric. The fabric is nonwoven in preferred embodiments. The metal-based hydrogen storage fibers provide excellent surface area and have a pore structure which is low-density in nature and thus light in weight. Due to the increased surface area and the nature of solid- state hydrogen storage, storage temperatures are close to ambient temperature and pressures are advantageously low.
[0017] In a further embodiment, a hydrogen storage vessel is provided, which is comparable in weight and volume with conventional fuel storage systems.
[0018] Still another embodiment of the present invention relates to providing a hydrogen storage vessel that efficiently absorbs and desorbs hydrogen gas.
[0019] In a first aspect, a hydrogen storage vessel is disclosed, comprising: a housing having an interior volume and at least one aperture, and a plurality of metal-based hydrogen storage fibers disposed within the interior volume of the vessel, wherein the metal-based hydrogen storage fibers are capable of selectively absorbing and releasing hydrogen gas.
[0020] In the second aspect, the metal-based hydrogen storage fibers are provided as a fabric.
[0021] In a third aspect, the vessel according to the second aspect, the fabric is nonwoven. [0022] In a fourth aspect, the vessel according to any of aspects 1 to 3 includes at least two different fibers connected via a binding agent or sintered together.
[0023] In a fifth aspect, the metal-based hydrogen storage fibers of the vessel according to any of aspects 1 to 4 include one or more metal-based compounds that form binary metal hydrides, ternary metal hydrides, quaternary metal hydrides, or quinary metal hydrides.
[0024] In a sixth aspect, the metal-based hydrogen storage fibers of the vessel according to any of aspects 1 to 5 include one or more of the following transition metals: titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper and zinc; optionally doped with another metal that can be one or more of the following: zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, and mercury; and wherein the transition metal is optionally alloyed with one or more of aluminum, boron and magnesium.
[0025] In a seventh aspect, the storage vessel according to any of aspects 1 to 6 has an operating pressure between 1 bar and 1500 bars, below 1 ,000 bars, below 500 bars, below 100 bars or below 40 bars.
[0026] In an eight aspect, the vessel according to any of aspects 1 to 7 can be charged and discharged at a temperature range between -60°C and 500°C, below 350°C, below 200°C or below 100°C.
[0027] In a ninth aspect, the surface area per gram of the metal-based hydrogen storage fibers of the vessel according to any of aspects 1 to 8 ranges from about 10 cm2/g to about 50,000 cm2/g.
[0028] In a tenth aspect, the hydride fibers of the vessel according to any of aspects 1 to 9 have a hydrogen absorption between 1 % and 15 wt%. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The invention will be better understood and other features and advantages will become apparent by reading the detailed description of the invention, taken together with the drawings, wherein:
[0030] FIG. 1 illustrates a hydrogen storage vessel according to one embodiment of the invention.
[0031] FIG. 2 is a cross-sectional view of the hydrogen storage vessel of FIG. 1 having hydrogen storage fibers arranged as a non-woven fabric therein.
[0032] FIG. 3 is a close-up view of the hydrogen storage fibers of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
[0033]With reference to FIG. 1 , a hydrogen storage vessel 10 is illustrated. Vessel 10 includes a body 20 having an interior volume 22. A plurality of metal-based hydrogen storage fibers are disposed within the interior volume of the vessel 10. Vessel 10 includes a hydrogen inlet 40 and a hydrogen outlet 42, each preferably including a valve 44.
[0034] FIG. 2 is a schematic illustration of a cross-sectional view of the hydrogen storage vessel of FIG. 1 through line A-A which includes the hydrogen storage fibers 30, which filled up inside the tank. The figure illustrates the fibers in the form of a fabric 50 including metal-based hydrogen storage fibers 30. The fabric 50 has a non-woven form. In other embodiments, the fabric can be woven.
[0035] FIG. 3 illustrates a close-up view of the non-woven hydrogen storage metal fabric 50, which optionally can be assembled in the form of a stack or a roll. Rolls can be formed by folding a sheet of non-woven fibers into a cylinder-like form.
[0036] The hydrogen storage fibers are adapted for storage of hydrogen, preferably in a solid phase, through the inclusion of metals or metal alloys that can absorb/hydrogen and form a metal hydride or metal hydride compounds and also desorb or otherwise release hydrogen gas. The reversible hydrogen storage of the fibers provides excellent volumetric storage density, which is greater than hydrogen storage as a compressed gas or liquid. The hydrogen storage fibers present fewer safety problems as compared to hydrogen stored as a gas or in a liquid phase. Desorption of the hydrogen can be well controlled.
[0037] The hydrogen storage fibers of the invention provide desirable hydrogen absorption typically from 1 to 15 wt% of the fibers, and preferably 5 wt% or higher, even more preferably 10 wt% or higher.
[0038] The hydrogen storage fibers can be packed into hydrogen storage tanks densely or loosely with a wide range of bulk densities, generally about 0.5 g/cc or less, desirably 0.1 g/cc or less.
[0039] The hydrogen storage fibers of the present invention can absorb and release or desorb hydrogen through a reversible formation of a metal hydride bond based on interstitial hydride formation. Interstitial hydrides are traditionally described as metal hydrides or metal hydride compounds. In the hydrogen storage fibers of the present invention, hydrogen can exist as either an atomic or diatomic entity and the hydride is formed by the absorption and insertion of hydrogen into the lattice of the fibers. Absorption capacity varies greatly, depending on the materials utilized and ambient conditions, among other factors.
[0040] The hydrogen storage fibers can be selected to have a desired lattice structure and thermodynamic properties to control the pressure and/or temperature at which hydrogen is absorbed and desorbed. Such working thermodynamic parameters can be modified and fine-tuned by an appropriate alloying method according to known methodologies.
[0041] The hydrogen storage fibers can include as an active hydrogen absorbing releasing material any metal-based material that forms a metal hydride or metal alloy hydride capable of reversibly storing hydrogen. By way of example, the hydrogen storage fibers can include, without limitation, an element chosen from Group IA alkali metals, Group HA alkaline earth metals, Group 11 IB lanthanides, or Group IVB transition metals. In one embodiment, the hydrogen storage fibers can include a transition metal capable of forming a reversible binary metal hydride including, without limitation, palladium, titanium, zirconium, hafnium, zinc, and/or vanadium.
[0042] Multi-component metal alloys are also encompassed as active hydrogen absorbing/releasing materials and can include, without limitation, combinations of Group IV elements with Group V through Group XI elements (based on the 1990 IIIPAC system in which the columns are assigned the numbers 1 to 18), as well as alloys including combinations of lanthanides (atomic numbers 57 to 71 ) with Group VII through Group XI elements. For example, the active hydrogen absorbing/releasing material can have the structure AxTy in which A can be one or more Group IV elements and T can be one or more Group V through Group XI elements. In some embodiments, a Group VI metal can be selected from Mo and W, and a Group VIII metal can be selected from Fe, Co, Ni, Pd, and Pt. In some embodiments, a Group VI metal can be Mo and a Group VIII metal can be selected from Co and Ni.
[0043] Still other materials that are useful to form the hydrogen storage fibers of the invention include metals or metal alloys that form hydride compounds such as AIH3 and LiAIF which offer exceptionally high performance in hydrogen release according to DOE studies. Such materials are useful for vehicle systems including exchangeable hydrogen storage vessels.
[0044] Additional materials suitable for hydrogen storage fibers include lithium-based metal alloys that form hydride compounds such as LiBF /MgFh, LiBH4/Mg2NiH4, Mg(BH4)2, 2LiNH4/MgH2, and 1 :1 LiNH2/MgH2.
[0045] In another embodiment, an active hydrogen absorbing/releasing material can have a compositional formula of
A1 -xMxT5-y-zByCz, wherein:
A=is an alloy of rare earth elements, typically including cerium and lanthanum;
M=La, Pr, Nd or Ce;
T=Ni;
B=Co;
C=Mn, Al or Cr; x=0.0 to 1.0; y=0.0 to 2.5; and z=0.0 to 1.0.
[0046] In additional embodiments, still other intermetallic compounds can be used in forming hydrogen storage fibers. Non limiting examples include metals or metal alloys that form hydride compounds such as MgH2, La(Ni,AI)sH7, and variants thereof. Still other intermetallic compounds include TiVo6,Cro.3Zro.3NbMo alloy and TiVzrNbHf alloys with specific examples including, but not limited to, quaternary TiVZrNb alloy, and quinary TiVZrNbTa and TiZrNbHfTa alloys.
[0047] Additional suitable materials include manganese-based and/or copper-based hydrogen storage fibers, e.g., Mn and Cu substituted TiFe intermetallic compounds.
[0048] Hydrogen storage fibers can also be formed from metal-organic frameworks (MOFs) which are crystalline materials having high and regular porosity.
[0049] In one embodiment, the hydrogen storage fibers can include a magnesium-based active material, i.e., magnesium hydride or a magnesium alloy hydride. Magnesium can exhibit a high theoretical gravimetric hydrogen density of about 7.6 wt. %, can reversibly bind hydrogen, and is abundant and available at relatively low cost. Mg(BH4)2 can exhibit a theoretical gravimetric hydrogen density of 14.7 wt.% and is shown experimentally to exhibit 12 wt. % reversible hydrogen density.
[0050] The hydrogen storage fibers can include one or more additives that can improve desirable characteristics of the material, e.g., thermodynamic characteristics, kinetic characteristics, hydrogen absorption density, power density, activation energy, heat transfer, strength characteristics, etc. For example, additives that can be incorporated in hydrogen storage fibers can include, without limitation, palladium, titanium, titanium oxide, titanium fluoride, scandium, zirconium, nickel, cobalt, manganese, iron, vanadium, silicon, iron oxide, platinum, ruthenium, or combinations of additives. When included, additives can generally be present in the hydrogen storage fibers in a total additive amount of up to about 10 wt. % of the material. [0051] In addition to an active hydrogen absorbing/releasing material, the hydrogen storage fibers can include an inert metal that aids in forming the fiber structure. The inert metal can exhibit a high strength to weight ratio (e.g., about 100 kN-m/kg or greater) and can be inert in that it can exhibit little or no absorption of hydrogen. By way of example, the inert metal can include aluminum, iron, titanium, etc. The hydrogen storage fibers can generally include the inert metal in an amount of about 1 wt. % to about 20 wt. %, for instance about 10 wt. % in some embodiments. The inert metal can provide strength to the hydrogen storage fibers and can also be utilized in design and control of other characteristics of the material. For instance, a magnesium composition including about 15 wt. % of aluminum can exhibit a binding energy to hydrogen of about 0.25 eV, which is lower than that of magnesium alone and corresponds to release of 1 bar hydrogen gas at 100° C.
[0052] The various components of the hydrogen storage fibers, including the base hydrogen absorbing/releasing metal or metal alloy, any additives, and the inert metal, can be present in the bulk hydrogen storage fibers at nano- and/or micro-scales, e.g., as grains in the solid, which can improve the thermodynamic and kinetic response of the material as well as mechanical characteristics of the material. Incorporating components as micro- or nanostructures within the hydrogen storage fibers, particularly when the hydrogen storage fibers is in the form of a high surface area porous structure, can also provide the materials with good reversibility, thereby enabling repeated absorptiondesorption cycles without significant loss of hydrogen storage capabilities. Good absorption/desorption kinetics are also beneficial to enable hydrogen to be absorbed/desorbed in a relatively short period of time.
[0053] For instance, when considering a magnesium-based hydrogen storage fibers active magnesium or magnesium alloy hydrides and dopants present at a micro- or nanoscale can improve the structural stability of the solid material during cycling as well as the hydrogen storage kinetics of the solid material, as magnesium nanoparticles can segregate at grain boundaries of the bulk material. By way of example, coupling nanoparticles of magnesium with palladium, platinum, and/or ruthenium nanocatalysts in formation of a high surface area porous metal fibers can improve the hydriding/dehydriding kinetics of the magnesium-based material as compared to larger bulk materials.
[0054] In one embodiment, the hydrogen storage fibers can include a titanium oxide additive. The addition of titanium dioxide nanoparticles to a magnesium based metal foam can improve hydrogenation performance of the hydrogen storage fibers through increased kinetics, lower working temperature, and excellent oxidation-resistance as compared to similar materials but for the addition of the titanium dioxide nanoparticles.
[0055] Similarly, inclusion of iron oxide in hydrogen storage fibers can increase the H2 absorption rate as compared to a similar material but for the addition of the iron oxide by facilitating nucleation and defects on the surface of the metal-based material and thereby reducing the diffusion distances of hydrogen atoms in the materials.
[0056] The hydrogen storage fibers of the present invention can be formed according to any suitable manufacturing process, for example any metal fiber forming process. The manufacturing process is selected so that the fibers retain the desired porosity and structure that promote hydrogen storage and metal hydride formation in the fiber.
[0057] Suitable manufacturing processes include, but are not limited to, machining processes similar to those which produce steel wool, drawing processes, such as bundle drawing, and coil shaving processes.
[0058] In one embodiment, the fibers are produced utilizing at least a drawing process. The raw material used for forming the fibers, such as rods or wires which are moved against a metal cutting tool, sometimes including toothed blades. The one or more blades move against the rods or wires shaving the same to generate thinner fiber-like wires, of material. The cutting tools press against the material producing a very fine fiber that is cut into desired lengths or rolled up continuously into rolls, similar to how steel wool is made.
[0059] The fiber can be cylindrical in shape or non-cylindrical. The cross section of the fiber can be circular or non-circular such as ellipsoidal, triangular, square, rectangular pentagonal, hexagonal, trapezoidal, parallelogram and other irregular and non- symmetrical shapes.
[0060] The fibers produced by the processes of the invention have a length as well as an equivalent diameter. As utilized herein, the term “equivalent diameter” is the diameter of an imaginary circle, which has the same surface area as the surface area of the fiber, cut perpendicular to the longitudinal or major axis of the fiber. The maximum equivalent diameter of the fiber can be super fine (about 25 microns), extra fine (about 35 microns), very fine (about 40) microns, or fine (about 50) microns, or larger. The fiber equivalent diameter can be from 0.1 to 500 microns. It is preferred to have fiber equivalent diameter less than 20 microns, more preferred less than 10 microns, even more preferred less than 5 microns, and the most preferred less than 1 micron.
[0061] The surface area of the fiber can be from 10 to 50,000 cm2/g. It is preferred to have surface area larger than 100 cm2/g, more preferred larger than 500 cm2/g, even more preferred larger than 1000 cm2/g, the most preferred larger than 5000 cm2/g.
[0062] The hydrogen storage fibers can be a mixture of different equivalent diameters or thicknesses. The length of the fibers is preferred to be greater than 5 mm, more preferred greater than 1000 mm, even more preferred greater than 100 meters, the most preferred greater than 1000 meters. It is also possible to have a mixture of fibers with different lengths.
[0063] Once the fibers are formed, they are arranged in a desired form, such the nonwoven fabric described hereinabove. The fabric or bulk fibers are then inserted into the vessel, such as the cylindrical tank shown in FIG. 1 . The vessel is sealed as desired and includes a hydrogen gas inlet and outlet, which may be the same tube or pipe or separate constructs.
[0064] The hydrogen storage vessel has an operating pressure between 1 bar and 1500 bars, preferably below 1000 bars, more preferably below 500 bars, even more preferably below 100 bars, most preferably below 40 bars. [0065] The hydrogen storage vessel has an operating temperature between -60°C to 500°C, more preferably below 350°C, even more preferably below 200°C, most preferably below 100°C.
[0066] For the avoidance of doubt, the compositions and methods of the present invention encompass all possible combinations of the components, including various ranges of said components, disclosed herein. It is further noted that the term ‘comprising’ does not exclude the presence of other elements. However, it is also to be understood that a description of a product comprising certain components also discloses a product consisting of these components. Similarly, it is also to be understood that a description on a process comprising certain steps also discloses a process consisting of these steps.
[0067] In accordance with the patent statutes, the best mode and preferred embodiment have been set forth; the scope of the invention is not limited thereto, but rather by the scope of the attached claims.