Flux pinning superconducting LH2 tank

Abstract

A cryogenic storage tank, such as a hydrogen fuel cell for an aircraft, includes an inner wall 52, and an outer wall 54 defining a space, wherein the inner wall and outer wall are spaced from one anot

Description

21 07 23

[0001] The present disclosure relates to cryogenic storage tanks. The disclosure has particular utility in connection with cryogenic storage tanks for containing highly volatile materials such as liquid hydrogen for powering vehicles such as airplanes, and will be described in connection with such utility, although other utilities are contemplated.

[0002] This section provides background information related to the present disclosure which is not necessarily prior art. This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all its features.

[0003] There are many types of cryogenic tank designs and some are even semi-structural like Stanley’s ingenious design of a vacuum flask from the 1900’s, however this design could not be effective at soft or moderate vacuum pressures. Because of this the Stanley design required advanced manufacturing processes, such as furnace welding in a purged environment. Typical prior art cryogenic tank formats include: • Vacuum Jacketed Multi-layer insulation (VJ MLI) which has very high thermal performance, but is not thermo structural by design, and is difficult to produce. • Foamglas for LNG, which is thermo structurally not good, heavy, time consuming to produce and not suitable for flight, plus made for only ambient (vs, e.g., medium vacuum) pressures. • Spray on foam insulation (SOFI) is generally not thermo structural, is of much lower thermal performance and is better suited to ambient pressures. • Perlite or microspheres have been used in soft vacuum (SV) in heavy ground standing double walled tanks, but are poured into the annulus as a bulk fill material and do not provide structural strength. 21 07 23

[0004] The use of cryogenic fluids such as liquid hydrogen (LH2) for powering fuel cell powered aircraft offers an attractive alternative to conventional liquid fossil fuel burning engines. Liquid hydrogen is stored in a liquid state at very low temperature, i.e., below -252°C (2IK). In order to maintain LH2 fuel stores in the tank in liquid state, the tank must be strong to maintain pressure on the fluid, and must be insulated. Typically cryogenic tanks are multiwalled structures with supports or studs maintaining space between the walls. The space between the tank walls also typically may contain insulating material and / or is evacuated, i.e., to form a vacuum.

[0005] In the case of an airplane, weight and space are at a premium. Accordingly, the tank should be as light weight as possible, while still maintaining sufficient structural integrity to contain the liquefied fuel stores, have sufficiently thermal insulating value, and be able to withstand temperature cycling, shock and high G loading. That is to say, cryogenic tanks must be light weight, strong, and relatively low cost to produce and service.

[0006] A conventional cryogenic tank 10 is illustrated in Fig. 1, and includes an inner wall 12 and an outer wall 14. Inner wall 12 is separated from outer wall 14 by a plurality of structural supports or studs 16. The space between inner wall 12 and outer wall 14 is sealed fluid tight and is evacuated to form a vacuum. The void 18 between the inner and outer walls 12, 14 also may be filled with a thermal insulating material, or the outer surface 20 of the inner wall 12 and / or the inner surface 22 of outer wall 14 may be coated at least in part with insulation.

[0007] In accordance with the present disclosure, there is provided a cryogenic storage tank comprising an inner wall and an outer wall defining a space, wherein the inner wall and the outer wall are spaced from one another by magnetic repulsion. By spacing the inner wall and the outer wall from one another by magnetic repulsion, cryogenic storage tanks made in accordance 21 07 23 with the present disclosure avoid the need for structural supports or studs, significantly reducing the weight of the tank and reducing the thermal losses.

[0008] In accordance with the present disclosure, the inner wall of the cryogenic tank includes superconducting wire embedded in or on a surface of the inner wall, while the outer wall has magnetic wire or magnets embedded in or on the surface of the outer wall. The outer wall is formed of a material permeable to magnetic fields. The inner wall and outer wall of the cryogenic storage tank are maintained spaced from one another by magnetic repulsion (flux pinning) without the need for internal structural supports or studs.

[0009] A superconductor is a material which is characterized by zero electrical resistivity when a temperature of the material is below the material’s so-called “critical temperature”. A superconductor also exhibits the property of diamagnetism; that is, superconductors are perfect diamagnets with a magnetic susceptibility of -1. A diamagnet is characterized by the generation of a repulsive force in a material which is subjected to an applied magnetic field. The repulsive force is caused by the quantum mechanical effect by which an applied magnetic field creates an induced magnetic field in the material which is directly opposed to the direction of the applied magnetic field.

[00010] Flux pinning is a phenomenon that occurs when flux vortices in a superconductor are prevented from moving within the bulk of the superconductor materials so that the magnetic pins are “pinned” to those locations. This pinning is what holds a superconductor in place thereby allowing it to levitate. In accordance with the present disclosure we maintain spacing between the inner and outer walls of a cryogenic storage tank by affixing superconductor material to the tank inner wall, and conventional magnetic material to the tank outer wall, whereupon the magnetic field from the conventional magnetic material on the tank outer wall induces a magnetic field in 21 07 23 the superconductor material creating a strong magnetic repulsive force between the superconductor material on the tank inner wall and the conventional magnetic material on the tank outer wall whereby to maintain spacing between the tank inner and outer wall.

[00011] Superconducting materials achieve superconductivity at their so-called “critical temperature”. In the case of type-II superconducting materials, the critical temperature is the boiling point of liquid nitrogen (77.3°K). Since liquid hydrogen boils at 20°K, in accordance with the present disclosure we use the temperature of the stored hydrogen to achieve superconductivity. That is to say, when the superconducting wire on the tank inner wall is cooled to below their critical temperature, e.g., when liquid hydrogen is present in the tank, a repulsive force is generated between the superconducting material on the tank inner wall and the conventional magnetic material on the tank outer wall creating magnetic levitation or repulsion between the inner and outer walls of the tank, maintaining the spacing between the inner and outer tanks.

[00012] In accordance with the present disclosure, superconducting material is embedded into or fixed to a surface of a cryogenic tank inner wall. Exemplary superconducting useful include type-II high-temperature superconducting metal and metal alloys selected from the group consisting of NbTi, Nb^Sn, YBa?Cu Ox (YBCO), MgB2, and BiaSraCaO, which are given as exemplary. Some high-temperature superconducting alloys (e.g., YBCO) are not easy to manufacture, as they require nearly perfect crystallinity combined with a very dense array of artificial pinning centers. Thus, some embodiments may incorporate Y2O3 nanoparticles into the alloy. In other embodiments, columnar defects may be introduced (e.g., as described in A. Crisan, V.-S. Dang, and P. Mikheenko, "Nano-engineered pinning centres in YBCO superconducting films," Physica C: Superconductivity and its Applications, vol. 533, pp. 118-132, 2017, incorporated herein by reference). In other embodiments, nano-inclusions such as WO3, TiO2, 21 07 23 BiFeOs and BaTiOs may enhance critical current density. The conventional magnets affixed to the tank outer wall may comprise permanent magnets or electro-magnets. Preferably the conventional magnets comprise so-called “super magnets” such as neodymium magnets and samarium-cobalt magnets. The conventional magnets also may comprise permanent ferro-magnets. The conventional magnets are embedded within or attached to the outer surface of the tank outer wall. In other embodiments, the conventional magnets are embedded within or attached to the inner surface of the tank outer wall. As the tank is filled with hydrogen, the liquid hydrogen drops the temperature of the tank inner wall and accordingly the temperature of the superconducting wires to below the critical temperature of the superconducting wires. As this point the superconducting wires exhibit significant magnetic flux opposite to the magnetic flux of the conventional magnets on the tank outer wall essentially causing the inner wall and the outer wall of the tanks to be held apart by magnetic repulsion forces. The inner and outer wall will remain from one another as long as the temperature of the superconducting wire attached to the wall of the tank remains below its critical temperature.

[00013] In order to prevent the tank inner wall from contacting the outer tank when the tank does not contain liquid hydrogen, the inner wall of the outer tank and / or the outer wall of the inner tank may include bumpers formed of an elastomeric material. Alternatively, the inner tank wall may be suspended within the outer tank wall by ties or filaments which are strong enough to maintain the inner wall tank spaced from the outer tank wall, but optionally not strong enough to support the inner tank wall within the outer tank wall when the tank is filled with liquid hydrogen. This results in a substantial weight and thermal transfer reduction as compared to a conventional cryogenic tank such as illustrated in Fig. 1 discussed above. 21 07 23

[00014] In accordance with one aspect of the disclosure there is provided a cryogenic storage tank comprising an inner wall and an outer wall defining a space, wherein the inner wall and outer wall are spaced from one another by magnetic repulsion.

[00015] In one embodiment the inner wall has superconducting material embedded in or on a surface of the inner wall, and the outer wall has conventional magnetic material embedded in or on a surface of the outer wall.

[00016] In one embodiment, the magnetic material is embedded within or attached to an outer surface of the tank outer wall.

[00017] In another embodiment, the magnetic material is embedded within or attached to an inner surface of the tank outer wall.

[00018] In another embodiment the outer wall is formed of a material permeable to magnetic fields.

[00019] In a still further embodiment the superconducting material comprises a type-II superconducting material.

[00020] In another embodiment the type-II superconducting material comprises a superconducting wire.

[00021] In a further embodiment the type-II superconducting material comprises a metal or metal alloy selected from the group consisting of NbTi, NbaSn, YBa2Cu3Ox, (YBCO), MgBs, and Bi2Sr2CaO.

[00022] In another embodiment, the type-II superconducting material comprises an alloy including nano-inclusions of Y2O3, WO3, TiCh, BiFeOs and / or BaTiOs. 21 07 23

[00023] In yet another embodiment the conventional magnetic material is selected from the group consisting of a ferro-magnetic material, or a rare earth magnets material such as neodymium magnetic material and samarium-cobalt magnetic material.

[00024] In another embodiment the conventional magnetic material comprises an electromagnet.

[00025] In a further embodiment the superconducting wire is arranged spaced from adjacent strands of superconducting wire.

[00026] In yet a further embodiment a plurality of elastomeric bumpers are provided projecting into the space between the inner wall and the outer wall of the tank.

[00027] In another embodiment the inner tank wall is suspended within the outer tank wall by ties or filaments which are strong enough to maintain the inner tank wall spaced from the outer tank wall when the tank is empty, but not strong enough to support the inner tank within the outer tank when the tank is filled with liquid.

[00028] The present disclosure also provides a vehicle comprising a cryogenic storage tank as above described.

[00029] In one embodiment the vehicle comprises a fuel cell powered aircraft.

[00030] In another embodiment the fuel cell comprises a hydrogen powered fuel cell.

[00031] In yet another embodiment the tank is at least partially filled with liquid hydrogen.

[00032] In still yet another embodiment the vehicle comprises a lighter than air aircraft.

[00033] In a yet other embodiment the tank is at least partially filled with helium. 21 07 23

[00034] According to aspect A of the present invention there is provided a cryogenic storage tank comprising an inner wall and an outer wall defining a space, wherein the inner wall and outer wall are spaced from one another by magnetic repulsion.

[00035] Preferably the inner wall has superconducting material embedded in or on a surface of the inner wall, and the outer wall has conventional magnetic material embedded in or on a surface of the outer wall.

[00036] Preferably the magnetic material is embedded within or attached to an outer surface of the tank outer wall.

[00037] Preferably the magnetic material is embedded within or attached to an inner surface of the tank outer wall.

[00038] Preferably the outer wall is formed of a material permeable to magnetic fields.

[00039] Preferably the superconducting material comprises a type-II superconducting material.

[00040] Preferably the type -II superconducting material comprises a superconducting wire.

[00041] Preferably the type-II superconducting material comprises a metal or metal alloy selected form the group consisting of NbTi, NbsSn, YBa2Cu3Ox and Bi2Sr2CaO.

[00042] Preferably the type-II superconducting material comprises an alloy including nano-inclusions of Y2O3, WO3, HO2, BiFeOs and / or BaTiOs.

[00043] Preferably the conventional magnetic material is selected from the group consisting of a ferro-magnetic material, and a rare earth magnetic material.

[00044] Preferably the rare earth magnetic material comprises neodymium magnetic material and samarium-cobalt magnetic material. 21 07 23

[00045] Preferably the conventional magnetic material comprises an electro-magnet.

[00046] Preferably the superconducting wire is arranged spaced from adjacent strands of superconducting wire.

[00047] Preferably the cryogenic storage tank further comprises a plurality of elastomeric bumpers projecting into the space between the inner wall and the outer wall of the tank.

[00048] Preferably the inner tank wall is suspended within the outer tank wall by ties or filaments which are strong enough to maintain the inner tank wall spaced from the outer tank wall when the tank is empty, but not strong enough to support the inner tank within the outer tank when the tank is filled with liquid.

[00049] Preferably the filaments are elastic.

[00050] According to aspect B of the present invention there is provided a vehicle comprising a cryogenic storage tank according to aspect A of the present invention.

[00051] In one alternative the vehicle comprises a fuel cell powered aircraft.

[00052] Preferably the fuel cell comprises a hydrogen powered fuel cell.

[00053] Preferably the tank is at least partially filled with liquid hydrogen.

[00054] In another alternative the vehicle comprises a lighter than air aircraft.

[00055] Preferably the tank is at least partially filled with helium.

[00056] Further features and advantages of the disclosure will be seen in the following detailed description, taken in conjunction with the accompanying drawings. The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations and are not intended to limit the scope of the present disclosure. In the drawings: Fig. 1 is a cross-sectional view of a prior art cryogenic tank; 21 07 23 Fig. 2 is a cross-sectional view of a cryogenic tank made in accordance with the present disclosure; Fig. 3 is a top plan view, in partial cross-section, of a cryogenic tank made in accordance with the present disclosure; Figs. 4a and 4b are magnetic flux diagrams illustrating the effect on magnetic flux introducing artificial pinning centers in a superconductor employed in the present disclosure; and Fig. 5 is a schematic view of a hydrogen fuel cell powered airplane having a cryogenic storage tank in accordance with the present disclosure.

[00057] Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[00058] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, 21 07 23 steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[00059] When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[00060] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[00061] Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element 21 07 23 or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[00062] As used herein the terms “superconductivity” and “superconductor” are used interchangeably, superconductor materials are materials that can be drawn or formed into a wire, and have a critical temperature, i.e., a temperature at which the material loses superconductivity below that of the boiling point of the liquid being stored in the cryogenic tank. In the case of hydrogen which has a boiling point of about 20°K, useful superconductor materials are so-called type-II superconductor materials, i.e., materials which have a critical temperature at most of 77.3°K. The type-II superconductor materials also are materials which do not lose superconducting state in the presence of an external magnetic field. Exemplary type-II superconductor materials useful in the present disclosure include NbTi, Nb >Sn, YbaaCu^Ox. MgBa, and BiaSraCO. which are given as exemplary.

[00063] And, as used herein conventional magnets include conventional permanent including ferro-magnets, rare earth magnets such as neodymium magnets and samarium-cobalt magnets, and electro-magnets.

[00064] Referring to Figs. 2 and 3, cryogenic tank 50 in accordance with the present disclosure includes an inner wall 52 and an outer wall 54. Inner wall 52 and outer wall 54 spaced from one another by magnetic repulsion as will be described below. The space between inner wall 21 07 23 52 and outer wall 54, void 58 is evacuated to form a vacuum. Void 58 also may be filled at least in part with thermal insulating material.

[00065] In accordance with the present disclosure, inner wall 52 of the cryogenic tank 50 includes superconducting wires 60 embedded in or on a surface of the inner wall. Wires 60 are spaced from one another, and preferably run parallel to one another. A plurality of conventional magnets 56 are mounted on the surface of the tank outer wall 54 (e.g., on the outer surface as shown). In some embodiments, conventional magnets 56 are mounted on the inner surface of the tank outer wall 54. Tank outer wall 54 is formed of a material permeable to magnetic fields such as a polymeric material. Tank 50 includes inlets and outlets (not shown) which are conventional for loading and withdrawing cryogenic fluid in and out of storage. Tank 50 comprises a plurality of bumpers 62 formed, e.g., of an elastomeric material on the inner wall 52 and / or outer wall 54 projecting into void 58 for keeping the inside and outer walls of the tank from contacting one another when the tank is empty. Alternatively, or additionally, the inner tank wall may be suspended within the outer tank wall by ties or filaments 64 which are strong enough to maintain the inner tank spaced from the outer tank wall when the tank is empty, but not strong enough to support the inner tank wall within the outer tank wall when the tank is filled with liquid hydrogen. In some embodiments, filaments 64 are elastic.

[00066] Alternatively, the magnets on the surface of the tank outer wall 54 may comprise electro-magnets 68, in which case, an electrical power supply 70, which could be a hydrogen fuel cell, and wiring 72 will need to be included.

[00067] In one embodiment, the superconductor material comprises YBCO is covered with magnetic Fe nanoparticles to produce artificial pinning centers following the teachings of Masih Mojarrad et al., “Using Magnetic Nanoparticles to Improve Flux Pinning in YBa2Cu3Ox Films”, 21 07 23 IEEE Conference Publication, incorporated herein by reference. Figs 4a and 4b are flux diagrams showing differences in magnetic flux between a samarium-cobalt sintered permanent magnet and untreated YBCO superconducting wire (Fig. 4a), and samarium-cobalt sintered permanent magnet and YBCO treated with Fe nanoparticles to produce artificial pinning centers, at the boiling temperature of liquid hydrogen (20°K) (Fig. 4b).

[00068] Fig. 5 schematically illustrates an airplane 80 which includes two electric motors 82A, 82B which are supplied by two parallel fuel cell systems 86A, 86B including two cryogenic hydrogen fuel tanks 88A, 88B, made in accordance with the present disclosure.

[00069] Cryogenic tanks made in accordance with the present disclosure offer many advantages over prior art tanks including: tanks made in accordance with the present disclosure can be light weight, as the outer vessel can be made of light weight polymeric material.

[00070] Tanks made in accordance with the present disclosure are also lighter in weight as requiring no structural inner vessel supports.

[00071] The tanks can be made to custom geometries, which is specifically useful, for example, for integration within an airplane’s existing spaces.

[00072] Tanks may be made using REACH (Registration Evaluation Authorization and Restriction of Chemicals) compliant non-toxic chemicals.

[00073] Tanks are robust to cryogenic cycling and vibration.

[00074] Various changes may be made in the foregoing disclosure without departing from the spirits and scope thereof. For example, while the foregoing disclosure has been described in particular with forming cryogenic storage tanks for storing liquid hydrogen for use in a fuel cell powered aircraft, the cryogenic storage tanks in accordance with the present disclosure also advantageously may be used for storing liquid helium for lighter than air aircraft. In such case 21 07 23 since helium boils at 4.2°K, type-I superconductor materials such as tantalum, niobium, and titanium and their alloys may be used. Also, cryogenic tanks made in accordance with the foregoing disclosure advantageously may be used in other applications including other forms of transportation as well as fixed storage tank applications for consumers, industrial, education and military applications.

[00075] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. Various changes and advantages may be made in the above disclosure without departing from the spirit and scope thereof.

Claims

21 07 231. A cryogenic storage tank comprising an inner wall and an outer wall defining a space, wherein the inner wall and outer wall are spaced from one another by magnetic repulsion, said storage tank further comprising a plurality of elastomeric bumpers projecting into the space between the inner wall and the outer wall of the tank.

2. The cryogenic storage tank of claim 1, wherein the inner wall has superconducting material embedded in or on a surface of the inner wall, and the outer wall has conventional magnetic material embedded in or on a surface of the outer wall.

3. The cryogenic storage tank of claim 2, wherein the magnetic material is embedded within or attached to an outer surface of the tank outer wall.

4. The cryogenic storage tank of claim 2 or claim 3, wherein the magnetic material is embedded within or attached to an inner surface of the tank outer wall.

5. The cryogenic storage tank of any of claim 1 to 4, wherein the outer wall is formed of a material permeable to magnetic fields.

6. The cryogenic storage tank of any of claims 2 to 5 when dependent on claim 2, wherein the superconducting material comprises a type-11 superconducting material.

7. The cryogenic storage tank of claim 6, wherein the type -II superconducting material comprises a superconducting wire.

8. The cryogenic storage tank of claim 6 or claim 7, wherein the type-II superconducting material comprises a metal or metal alloy selected from the group consisting of NbTi, NbxSn, YBa2Cu30x and Bi2Sr2CaO.21 07 239. The cryogenic storage tank of any of claims 6 to 8, wherein the type-II superconducting material comprises an alloy including nano-inclusions of Y2O3, WO3, TiO?, BiFeOs and / or BaTiO3.

10. The cryogenic storage tank of any of claims 2 to 9, when dependent on claim 2 wherein the conventional magnetic material is selected from the group consisting of a ferro-magnetic material, and a rare earth magnetic material.II. The cryogenic storage tank of claim 10, wherein the rare earth magnetic material comprises neodymium magnetic material and samarium-cobalt magnetic material.

12. The cryogenic tank of any of claims 2 to 11, when dependent on claim 2 wherein the conventional magnetic material comprises an electro-magnet.

13. The cryogenic storage tank of any of claims 7 to 12 when dependent on claim 7, wherein the superconducting wire is arranged spaced from adjacent strands of superconducting wire.

14. The cryogenic storage tank of any preceding claim wherein the inner tank wall is suspended within the outer tank wall by ties or filaments which are strong enough to maintain the inner tank wall spaced from the outer tank wall when the tank is empty, but not strong enough to support the inner tank within the outer tank when the tank is filled with liquid.

15. The cryogenic storage tank of claim 14, wherein the filaments are elastic.

16. A vehicle comprising a cryogenic storage tank as claimed in any of claims 1-15.

17. The vehicle of claim 16, wherein the vehicle comprises a fuel cell powered aircraft.

18. The vehicle of claim 17, wherein the fuel cell comprises a hydrogen powered fuel cell.

19. The vehicle of claim 18, wherein the tank is at least partially filled with liquid hydrogen.

20. The vehicle of claim 16, wherein the vehicle comprises a lighter than air aircraft.

21. The vehicle of claim 20, wherein the tank is at least partially filled with helium.

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