Hydrogen storage tank with a nanoporous venting layer

Abstract

Storage tank (10) for a gas, the storage tank (10) comprising: a liner (12) comprising a polymer and defining an inner chamber (24), an extension (26, 26') coupled to the lining (12), an intermediate layer (28) covering a portion of the boss (26, 26') and the liner (12), wherein the intermediate layer (28) comprises an interlocking fabric comprising carbon, silicon dioxide, a polymer, a metal-organic framework, or combinations thereof and pores having a diameter greater than the diameter of a hydrogen molecule and less than or equal to 2 nm, and wherein the intermediate layer (28) is not pyrolyzed, and an outer shell (36) comprising a carbon fiber reinforced composite material, the outer shell (36) covering the intermediate layer (28) except for an intermediate layer end (30, 34) in contact with the projection (26, 26'), such that the intermediate layer end (30, 34) of the intermediate layer (28) defines an intermediate layer ring (38, 38') exposed to an external environment, wherein the storage tank (10) is designed such that when gas diffuses through the liner (12) to the intermediate layer (28), the intermediate layer (28) directs the gas out of the exposed interlayer ring (38, 38').

Description

IntroductionThis section contains background information related to the present disclosure that is not necessarily prior art.Hydrogen-powered vehicles generate mechanical energy from hydrogen gas by either combusting hydrogen gas in an internal combustion engine or reacting hydrogen gas with oxygen in a hydrogen fuel cell that powers an electric motor. Regardless of whether the hydrogen-powered vehicle generates power by combustion or with a fuel cell, the hydrogen gas needs to be stored in a storage tank. Such a storage tank is disclosed, for example, in U.S. Pat. No. 2021 / 0 010 640 A1 or DE 10 2015 201 788 A1. Further prior art includes the publications US 2013 / 0 341 235 A1, DE 10 2008 039 573 A1 and US 2017 / 0 336 031 A1.Hydrogen gas type IV storage tanks include an inner polymeric liner defining an inner storage chamber and an outer shell. In a full storage tank, a high internal pressure generated by the hydrogen gas forces the liner outward toward the outer shell in such a manner that the pressure forces the liner against the outer shell. However, as the pressure decreases due to defueling and because hydrogen gas molecules (H2) are very small--having a diameter of about 2.5 Å (0.25 nm), hydrogen molecules may diffuse through the liner and become trapped between the liner and the outer shell. If larger amounts of hydrogen gas diffuse through the liner, a space filled with hydrogen gas is created between the liner and the outer shell, causing a portion of the liner adjacent the space to warp and flex inwardly. Therefore, modified type IV storage tanks that prevent or minimize deflection resulting from the formation of gas inclusions between a liner and an outer shell are desirable.SUMMARYIt is thus an object of the invention to provide a more stable storage tank.This object is achieved by a storage tank having the features of claim 1 and by a method according to claim 4.Hereinafter, this section contains a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.In various aspects, the present technology provides a storage tank for a gas, the storage tank comprising: a liner having a first end portion, a central body portion, and a second end portion opposite the first end portion, the liner defining an interior chamber; a boss coupled to the first end portion of the liner; an intermediate layer disposed around the liner and the boss in such a manner that the intermediate layer extends from a first intermediate layer end at an exposed outer surface of the boss, around the central body portion of the liner, and around at least a portion of the second end portion of the liner to a second intermediate layer end opposite the first intermediate layer end; and an outer shell covering substantially the entire interlayer except the first interlayer end and optionally the second interlayer end so that the first interlayer end and optionally the second interlayer end are exposed to an external environment, wherein the storage tank is configured such that when gas diffuses through the liner to the interlayer, the interlayer discharges the gas from the first interlayer end of the interlayer to the external environment.In one aspect, the liner comprises a polymer having a density of greater than or equal to about 900 kg / mm 3 to less than or equal to about 1200 kg / mm 3.In one aspect, the polymer comprises polyamide, polyethylene, ethylene polypropylene, polytetrafluoroethylene, or combinations thereof.In one aspect, the intermediate layer comprises an interdigitated web comprising pores having an average diameter of greater than or equal to about 500 μm to less than or equal to about 2 nm and a porosity of greater than or equal to about 15% to less than or equal to about 85%.In one aspect, the interlocking web comprises an interlayer material comprising carbon, silica, a polymer, an organometallic framework, or combinations thereof.In one aspect, the interlocking web further comprises a binder.In one aspect, the binder comprises styrene-butadiene rubber, cellulose, polyvinylpyrrolidone, polyvinylidene fluoride, perfluorobutylethylene, perfluorobutylvinylether, trifluoroethylene, hexafluoropropene, hexafluoroisobutylene, pentafluoropropene, polyvinyl alcohol with sulfosuccinic acid, polytetrafluoroethylene, polystyrene-polyethylene oxide, a polyamide, polypropylene carbonate, polyethylene carbonate, poly(cyclohexenepropylene)carbonate, butylene carbonate, or combinations thereof.In one aspect, the outer shell comprises a carbon fiber reinforced composite.In one aspect, the first interlayer end exposed to the external environment defines an interlayer ring disposed around the boss, the interlayer ring having a thickness greater than or equal to about 0.1 mm to less than or equal to about 2 mm.In one aspect, the storage tank further comprises a second boss coupled to the second end portion of the liner, wherein the intermediate layer extends to the second intermediate layer end at an exposed outer surface of the second boss, and the outer shell does not cover the second intermediate layer end such that the second intermediate layer end is exposed to the external environment, wherein the storage tank is configured such that when gas diffuses through the liner to the intermediate layer, the intermediate layer discharges the gas from the first intermediate layer end or the second intermediate layer end of the intermediate layer to the external environment.In various aspects, the present technology further provides a storage tank for a gas, the storage tank comprising: a liner having a polymer and defining an interior chamber; a boss coupled to the liner; an intermediate layer covering a portion of the boss and the liner, wherein the intermediate layer comprises an interlocking fabric comprising carbon, silica, a polymer, an organometallic framework, or combinations thereof, and pores having a diameter greater than the diameter of a hydrogen molecule and less than or equal to about 2 nm, and wherein the intermediate layer is not pyrolyzed; An outer shell comprising a carbon fiber reinforced composite, wherein the outer shell covers the intermediate layer except for an intermediate layer end in contact with the boss such that the intermediate layer end of the intermediate layer defines an intermediate layer ring exposed to an external environment, wherein the storage tank is configured such that when gas diffuses through the liner to the intermediate layer, the intermediate layer directs the gas out of the exposed intermediate layer ring.In one aspect, the interdigitating web of the intermediate layer has a porosity of greater than or equal to about 15% to less than or equal to about 85%.In one aspect, the intermediate layer further comprises a binder selected from the group consisting of styrene-butadiene rubber, cellulose, polyvinylpyrrolidone, polyvinylidene fluoride, polypropylene carbonate, polyethylene carbonate, poly(cyclohexenepropylene) carbonate, butylene carbonate, and combinations thereof.In various aspects, the present technology further provides a method of manufacturing a storage tank for a gas, the method comprising: coupling a liner to a liner defining an interior chamber; applying an intermediate layer over the liner and over a portion of the liner, the intermediate layer having an interlocking web comprising pores having a diameter greater than the size of a hydrogen molecule and less than or equal to about 2 nm and a binder; forming an outer shell on the intermediate layer except for an intermediate layer end in contact with the boss such that the intermediate layer end defines an intermediate layer ring exposed to an external environment, wherein the storage tank is configured such that when gas diffuses through the liner to the intermediate layer, the intermediate layer directs the gas out of the exposed intermediate layer ring.In one aspect, coupling the boss to the liner includes threading the boss into the liner through a thread on an inner surface of the boss and a complementary thread on an outer surface of the liner.In one aspect, the intermediate layer is formed by forming a mixture comprising a precursor powder and the binder, casting a layer of the mixture onto a substrate, drying the layer to form the intermediate layer, and optionally calendering the intermediate layer.In one aspect, the mixture comprises the precursor powder at a concentration of greater than or equal to about 70% by weight to less than or equal to about 95% by weight and the binder at a concentration of greater than or equal to about 5% by weight to less than or equal to about 30% by weight.In one aspect, the precursor powder comprises carbon, silica, a polymer, an organometallic backbone, or combinations thereof, and the binder comprises styrene-butadiene rubber, cellulose, polyvinylpyrrolidone, polyvinylidene fluoride, polypropylene carbonate, polyethylene carbonate, poly(cyclohexenepropylene) carbonate, butylene carbonate, or combinations thereof.In one aspect, the method further comprises, prior to applying the green interlayer, applying an adhesive to the interlayer and the portion of the formulation.In one aspect, the intermediate layer includes an additive binder and is in green form, and the method further comprises, after the forming, heating the storage tank at a temperature of greater than or equal to about 90° C. to less than or equal to about 160° C. to remove at least a portion of the additive binder from the intermediate layer in green form and convert the intermediate layer in green form into a porous intermediate layer having a relatively higher porosity than the intermediate layer in green form.Further areas of applicability will become apparent from the description herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.DRAWINGSThe 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. FIG. 1 shows a storage tank according to various aspects of the present technology in a schematic illustration. FIG. 2 shows a first part of the storage tank shown in FIG. 1 in an enlarged view. FIG. 3 shows a second part of the storage tank shown in FIG. 1 in an enlarged view. FIG. 4 shows the storage tank shown in FIG. 1 in a non-sectional view along plane 4. FIG. 5 illustrates a method of manufacturing a storage tank according to various aspects of the present technology. Fig. 6A shows a first decomposition reaction of a polymeric additive binder. Fig. 6B shows a second decomposition reaction of a polymeric additive binder.Corresponding reference numerals designate corresponding parts throughout the several views of the drawings.DETAILED DESCRIPTIONEmbodiments are provided so that this disclosure will be thorough and will be fully understood by those skilled in the art. Numerous specific details are set forth, such as examples of specific compositions, components, devices, and methods, in order to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be used, that embodiments may be embodied in many different forms, and that neither one nor the other should be construed to limit the scope of the disclosure. In some embodiments, known processes, device structures, and technologies are not described in detail.The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" may also include the plural forms unless the context clearly indicates otherwise. The terms "comprise," "comprising," "include," and "have" are inclusive and therefore specify the presence of stated features, elements, compositions, steps, integers, operations, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Although the open term "comprising" is intended to be a non-limiting term that serves to describe and claim various embodiments set forth herein, in certain aspects, the term may alternatively be understood as a limiting and restrictive term, such as "consisting of" or "consisting essentially of.". Therefore, for any given configuration specifying compositions, materials, components, elements, features, integers, operations, and / or method steps, the present disclosure expressly also encompasses configurations consisting of or consisting essentially of such specified compositions, materials, components, elements, features, integers, operations, and / or method steps. In the case of "consisting of", the alternative embodiment excludes any additional compositions, materials, components, elements, features, integers, operations, and / or process steps, while in the case of "consisting essentially of", any additional compositions, materials, components, elements, features, integers, operations, and / or process steps that significantly impact the basic and novel characteristics are excluded from such an embodiment, but any compositions, materials, components, elements, features, integers, operations, and / or process steps that do not significantly impact the basic and novel characteristics may be included in the embodiment.All method steps, processes, and operations described herein are not to be construed as necessarily requiring execution in the particular order discussed or illustrated, unless expressly characterized as the order of execution. It will be appreciated that additional or alternative steps may be employed unless otherwise indicated.When a component, element, or layer is referred to as being "on" or "engaged to" another element or layer, or as being "connected" or "coupled" to or the same, it may be directly on or engaged to or connected to or coupled to the other component, element, or layer, or intervening elements or layers may be present. On the other hand, when an element is referred to as being "directly on" or "directly engaged to" another element or layer, or as being "directly connected" or "directly coupled" to or the same, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent," or "adjacent" versus "directly adjacent," or "directly adjacent," etc.). As used herein, the term "and / or" includes any combination of one or more of the associated listed items.Although the terms "first," "second," "third," etc. may be used herein to describe various steps, elements, components, regions, layers, and / or sections, these steps, elements, components, regions, layers, and / or sections should not be limited by these terms unless otherwise specified. These terms may be used only to distinguish one step, element, component, region, layer, or portion from another step, element, component, region, layer, or portion. Terms such as "first," "second," and other numerical terms, when used herein, do not imply a sequence or order unless the context clearly indicates that. Thus, a first step, element, component, region, layer, or portion discussed below could be referred to as a second step, element, component, region, layer, or portion without departing from the teachings of the embodiments.Spatially or temporally relative terms such as "before," "after," "inner," "outer," "below," "under," "lower," "over," "upper," and the like may be used herein for convenience to describe the relationship of an element or feature to one or more other elements or features as illustrated in the figures. Spatially or temporally relative terms may be intended to include different orientations of the device or system in use or operation in addition to the orientation depicted in the figures.Throughout this disclosure, the numerical values represent approximate dimensions or limits for ranges to include minor deviations from the stated values and configurations that have approximately the stated value, as well as those values that have exactly the stated value. Unlike the working examples at the end of the detailed description, all numerical values of parameters (e.g., amounts or conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term "about", regardless of whether or not "about" actually appears before the numerical value. "About" means that the numerical value indicated permits slight imprecision (with some approximation to the accuracy of the value, about or rather close to the value, near). Where the imprecision given by "about" is not otherwise understood by this common meaning in the art, then "about" as used herein means at least modifications that may result from common methods of measuring and using such parameters. For example, "about" may comprise a deviation of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in certain aspects less than or equal to 0.1%.Moreover, the disclosure of ranges includes the disclosure of all values and further divided ranges within the entire range, including the endpoints and the sub-ranges indicated for the ranges.Embodiments will now be described in more detail with reference to the accompanying drawings.The present technology provides a modified type IV storage tank, referred to herein simply as a "storage tank" or "gas storage tank", that includes an intermediate layer, also referred to herein as a "venting layer", between a liner and an outer shell. The intermediate layer receives hydrogen (H 2-) molecules that diffuse through the liner and directs them to an environment outside the storage tank. Removal of H 2- molecules that diffuse through the liner from the tank prevents or minimizes distortion and flexing of the liner. Methods of manufacturing the storage tank are also provided by the current technology.Referring to FIG. 1, the present technology provides a storage tank 10 for a gas such as H 2( g). In particular, FIG. 1 shows a cross-sectional view of the storage tank 10. the storage tank 10 includes a liner 12 including a first end portion 14 defining a port 16, a central body portion 18, and a second end portion 20 opposite the first end portion 14. More specifically, the liner 12 defines and extends about a longitudinal axis 22 from the opening 16 at the first end portion 14 across the central body portion 18 to the second end portion 20. As shown in FIG. 1, the liner 12 defines a second port 16' at the second end portion 20. The liner 12 defines an interior chamber 24 in which the gas is stored. In certain aspects, the liner 12 has a thickness of greater than or equal to about 2 mm and less than or equal to about 10 mm.The liner 12 comprises a polymer having a density greater than or equal to about 900 kg / m 3 to less than or equal to about 1200 kg / m 3 and including density values of about 900 kg / m 3, about 950 kg / m 3, about 1000 kg / m 3, about 1050 kg / m 3, about 1100 kg / m 3, about 1150 kg / m 3 or about 1200 kg / m 3. The polymer includes, for example (but is not limited to), polyamide, polyethylene (e.g., high density polyethylene), polyethylene terephthalate, ethylene vinyl alcohol, polytetrafluoroethylene, or combinations thereof.The storage tank 10 further includes a boss 26 coupled to the first end portion 14 of the liner 12 at the port 16. In some modifications, the boss 26 is press fit to and secured to the terminal 16 via an optional adhesive to the first end portion 14 of the liner 12. In other variations, the terminal 16 on the first end portion 14 of the liner 12 has an external thread and the boss 26 has an internal thread complementary to the external thread, and the boss 26 is coupled to the first end portion 14 of the liner 12 via the external thread of the first end portion 14 of the liner 12 and the internal thread of the boss 26. As shown in FIG. 1, the storage tank 10 may also include a second boss 26' coupled to the second end portion 20 of the liner 12 at the second port 16'. However, as discussed above, in some modifications, the storage tank 10 includes only the boss 26 at the first end portion 14 of the liner 12.The storage tank 10 further includes an intermediate layer or venting layer 28. the intermediate layer 28 is disposed about the liner 12 and the boss 26 in such a manner that the intermediate layer 28 extends from a first intermediate layer end 30 at an exposed outer surface 32 of the boss 26 at the first end portion 14 of the liner 12, about the central body portion 18 of the liner 12, and about at least a portion of the second end portion 20 of the liner 12 to a second intermediate layer end 34 opposite the first intermediate layer end 30 at a second exposed outer surface 32' of the second boss 26'. As discussed above, it is apparent that in some variations, the storage tank 10 includes only the boss 26 at the first end portion 14 of the liner 12 and the second end portion 20 of the liner is closed so that there is no second boss 26' and no second interlayer end 34. In certain aspects, the intermediate layer 28 has a thickness of greater than or equal to about 20 μm and less than or equal to about 2 mm.In certain aspects, the intermediate layer 28 is bonded to the liner 12, the boss 26, and / or the second boss 26' by an adhesive. Thus, although not shown in the figure, the storage tank 10 may include an adhesive layer disposed between the liner 12, the boss 26 and / or the second boss 26' and the intermediate layer 28. For example, if present, the adhesive is (but is not limited to) a high viscosity adhesive such as a high speed adhesive, a water-based paste, silicone-based adhesives, a cyanoacrylate gel, and combinations thereof.The intermediate layer 28 comprises an interdigitated web or matrix comprising pores having an average diameter greater than the diameter of an H2 molecule (about 2.5 Å or 0.25 nm) to less than or equal to about 2 nm, such as a diameter greater than or equal to about 500 μm to less than or equal to about 2 nm. The interdigitated web or matrix of the intermediate layer 28 has a porosity (i.e., a proportion of the total volume of pores to the total volume of the intermediate layer 28) of greater than or equal to about 15% to less than or equal to about 85%, including porosities of about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, or about 85%.The interdigitated web or matrix of the interlayer 28 comprises an interlayer material. The interlayer material includes, for example (but is not limited to), carbon, silica, a polymer, an organometallic framework, or combinations thereof. The carbon may be, for example (but not limited to), high surface area activated carbon, porous carbon of pyrolyzed polymers, graphite carbon, carbon nanotubes, fullerenes (e.g., C60, C20, etc.), or combinations thereof. The silica may be, for example (but not limited to), silica (SiO 2), a zeolite, or a combination thereof. The polymer may be, for example (but not limited to), highly crosslinked polymers, polymer networks, or a combination thereof. The metal organic framework (MOF) includes metal ions or clusters coordinated with organic ligands to form three-dimensional structures, and may be, for example (but not limited to), Zr(IV) biphenyl dicarboxylate (UiO-67), copper benzene 1,3,5-tricarboxylate (HKUST-1), aluminum terephthalate (MIL-53), 2-methylimidazole zinc salt (ZIF-8), Zn4O(benzodicarboxylate) 3( MOF-5), or combinations thereof. The interlayer material is made of a porous powder having a large surface area capable of absorbing H 2( g).In some variations, the intermediate layer 28 further comprises a binder distributed throughout the entire intermeshing tissue or matrix. Non-limiting examples of suitable binders include styrene-butadiene rubber, cellulose, polyvinylpyrrolidone, polyvinylidene fluoride, perfluorobutylethylene, perfluorobutylvinylether, trifluoroethylene, hexafluoropropene, hexafluoroisobutylene, pentafluoropropene, polyvinyl alcohol with sulfosuccinic acid, polytetrafluoroethylene, polystyrene-polyethylene oxide, a polyamide, or combinations thereof. When comprising the binder, the intermediate layer 28 may be considered "green", "a green intermediate layer", or "an intermediate layer present in green form". the porosity of the intermediate layer 28 may be reduced by calendering the intermediate layer, wherein pressure, with or without heat, is applied to the intermediate layer 28 to increase its density. If higher porosity is desired, the binder may be combined with an additional binder, wherein the additional binder is a carbonate such as (but not limited to) polypropylene carbonate (e.g., NB-180 PPC from Novomer Inc.), polyethylene carbonate, poly(cyclohexenepropylene) carbonate, butylene carbonate, and combinations thereof. These additional binders are "sacrificial" and can be sublimed at elevated temperatures to impart additional porosity. In some aspects, when the additional binder is removed, the intermediate layer 28 has a higher porosity and thus a higher H 2( g) permeability than the intermediate layer 28 comprising the additional binder.In certain variations, while the intermediate layer 28 may comprise porous carbon made from pyrolyzed polymers, the intermediate layer 28 itself is not pyrolyzed.Referring again to FIG. 1, the storage tank 10 further includes an outer shell 36. the outer shell 36 covers substantially the entire intermediate layer 28 except for the first intermediate layer end 30 and the second intermediate layer end 34 (if present) such that the first intermediate layer end 30 and the second intermediate layer end 34 (if present) are exposed to an external environment, i.e., to an environment external to the storage tank 10. The first interlayer end 30 and the second interlayer end 34 (if present) exposed to the external environment define an interlayer ring 38 disposed around the boss 26 and, if the second boss 26' is present, a second interlayer ring 38'. The interlayer rings 38, 38' have a thickness TIRof greater than or equal to about 0.1 mm to less than or equal to about 2 mm, including a thickness of about 0.1 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm, about 1.6 mm, about 1.7 mm, about 1.8 mm, about 1.9 mm, or about 2 mm (see FIGS. 3 and 4 ).The outer shell 36 comprises a carbon fiber reinforced composite comprising carbon fibers having a tensile strength of greater than or equal to about 700 psi (1 psi≈6895 Pa). The carbon fibers are embedded in a polymer resin, which may be a thermosetting resin such as a phenol resin or a thermoplastic resin such as a polyamide. In certain aspects, the outer shell 36 has a thickness of greater than or equal to about 6 mm and less than or equal to about 40 mm.FIGS. 2 and 3 show parts 2, 3 of the storage tank 10 shown in FIG. 1 in an enlarged view. As seen in these views, the storage tank 10 is configured such that when gas diffuses through the liner 12 to the intermediate layer 28, the gas permeates through the intermediate layer 28 and the intermediate layer 28 discharges the gas from the first intermediate layer end 30 of the intermediate layer 28 defining the intermediate layer ring 38 to the external environment. If the storage tank 10 comprises the two lugs 26, 26', the storage tank 10 is designed such that when gas diffuses through the liner 12 to the intermediate layer 28, the gas penetrates through the intermediate layer 28, which conducts the gas out of the first intermediate layer end 30 and / or the second intermediate layer end 34 of the intermediate layer 28 into the external environment. FIG. 4 shows the storage tank 10 shown in FIG. 1 in a non-sectional view along plane 4.Referring to FIG. 5, the present technology also provides a method 50 for manufacturing the storage tank discussed above. The method includes providing the liner 12 as described above. The liner 12 may be manufactured as a single monolithic unit by blow molding or rotation or by welding together two injection molded halves of the liner 12. When the halves are welded together to form the liner 12, the flash should be removed.The method 50 also includes coupling the tab 26 and the second tab 26' (as discussed above) to the liner 12.Thereafter, the method 50 includes forming the intermediate layer 28 (as discussed above) on a portion of the tabs 26, 26' and over the liner 12. The interlayer material 52 may be in green form or in a form in which an additive binder has been removed. In either form, the interlayer material 52 is an elastic film or sheet that can be wound manually or mechanically around the tabs 26, 26' and the liner 12.In some variations, the method 50 includes applying an adhesive, such as a high viscosity adhesive, to the liner 12, to a portion of the boss 26, and / or to a portion of the second boss 26' before the interlayer material 52 is applied.The interlayer material 52 is prepared by forming a mixture comprising a precursor powder, a binder, an optional additional binder, and a solvent. The mixture comprises the precursor powder at a concentration of greater than or equal to about 70% by weight to less than or equal to about 95% by weight and the binder at a concentration of greater than or equal to about 5% by weight to less than or equal to about 30% by weight. The precursor powder comprises a carbon powder, a silica powder, a polymer powder, an organometallic framework powder, or combinations thereof, wherein the carbon, the silica, the polymer, and the organometallic framework are discussed above. The binder and the additive binder are also discussed above. Non-limiting examples of the solvent include methoxybenzene (anisole), dichloromethane, tetrahydrofuran, ethyl acetate, diethyl ether, methylene chloride, carbon tetrachloride, chloroform, toluene, benzene, cyclohexane, hexane, pentane, acetone, methyl ethyl ketone, N-methylpyrrolidone, and combinations thereof. The method of making the interlayer material 52 then includes casting a layer of the mixture onto a substrate. The substrate comprises any material whose cohesive forces are so low that the interlayer material 52 can ultimately be removed therefrom. Exemplary substrate materials include polytetrafluoroethylene and glass. Casting is performed by doctor blade, spin casting, casting, or any other method known in the art. In some variations, the layer is cast to a predetermined thickness. Thereafter, the method of making the interlayer material 52 includes drying the layer and removing at least a portion of the solvent to form the interlayer material 52 (in green form when the additional binder is included). Optionally, the method further comprises calendering the interlayer material 52 to reduce porosity or achieve a predetermined thickness. When comprising the additive binder, the interlayer material 52 may be used in green form and optionally heated to remove the additive binder after forming the storage tank, or the interlayer material 52 present in green form may be heated to remove the additive binder before forming the interlayer 28.After the interlayer material 52 is applied and the interlayer 28 is formed (as discussed above), the method 50 includes forming the outer shell 36 (as described above) on the interlayer 28, except for the interlayer ends 30, 34 of the interlayer 28 that are in contact with the tabs 26, 26' such that the interlayer ends 30, 34 of the interlayer 28 define the interlayer rings 38, 38' that are exposed to an external environment (as described above). The formation of the outer shell 36 is accomplished by winding in which polymer resin impregnated carbon fibers 54 (as described above) are drawn from a rotating mandrel 56, combined and wound around the intermediate layer 28 and the tabs 26, 26' in one of two methods - wet-winding or TowPreg-winding. In the wet-winding process, the carbon fibers 54 are passed through a bath of uncured polymer resin before being wound around the intermediate layer 28 and the tabs 26, 26'. In the TowPreg Windowing process, the carbon fibers are prepregged with the uncured polymer resin and wound directly around the intermediate layer 28 and the lugs 26, 26'. By rotating the intermediate layer 28 and the tabs 26, 26' and by moving the mandrel 56 laterally, the polymer resin impregnated carbon fibers 54 are wound around the intermediate layer 28 and the tabs 26, 26' until a desired or predetermined thickness is reached. The carbon fibers 54 impregnated with the polymer resin are then cured at a temperature of greater than or equal to about 150° C. to less than or equal to about 200° C., including temperatures of about 150° C., 155° C., 160° C., 165° C., 170° C., 175° C., 180° C., 185° C., 190° C., 195° C., and 200° C., for a period of greater than or equal to about 1 hour to less than or equal to about 24 hours, and then cooled to ambient temperature or room temperature to form the outer shell 36.Optionally, when the intermediate layer 28 comprises an additive binder (as discussed above) and is in green form, the method comprises removing the additive binder by heating the storage tank at a temperature of greater than or equal to about 90° C. to less than or equal to about 160° C., including temperatures of about 90° C., about 95° C., about 100° C., about 105° C., about 110° C., about 115° C., about 120° C., about 125° C., about 130° C., about 135° C., about 140° C., about 145° C., about 150° C., about 155° C., and about 160° C., to remove and convert at least a portion of the binder from the intermediate layer present in green form to a form, which has a relatively higher porosity (and a higher H 2( g) permeability). In some aspects, the above-described curing is conducted at a temperature sufficient to remove the additive binder, and an additional step is not required. The heating decomposes the additional binder. Using polypropylene carbonate as an exemplary additional binder, FIG. 6A shows a decomposition path in which an alkoxide backbone mechanism 60 and a carbonate backbone mechanism 62 cleave the polypropylene carbonate into two propylene carbonate molecules. As shown in FIG. 6B, a random chain splitting mechanism 64 removes carbon dioxide molecules from the polypropylene carbonate. The degradation products, e.g., propylene carbonate and carbon dioxide, sublimate and exit the storage tank through the interlayer rings 38, 38'.The foregoing description of the embodiments is illustrative and illustrative. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular configuration are generally not limited to that particular configuration, but are interchangeable where appropriate and may be used in a selected configuration, although not specifically shown or described. They can also be modified in many ways. Such modifications 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.

Claims

A storage tank (10) for a gas, the storage tank (10) comprising: a liner (12) comprising a polymer and defining an interior chamber (24); a boss (26, 26') coupled to the liner (12); an intermediate layer (28) covering a portion of the boss (26, 26') and the liner (12), wherein the intermediate layer (28) comprises an intermeshing tissue comprising carbon, silica, a polymer, an organometallic framework, or combinations thereof, and pores having a diameter greater than the diameter of a hydrogen molecule and less than or equal to 2 nm, and wherein the intermediate layer (28) is not pyrolyzed; and an outer shell (36) comprising a carbon fiber reinforced composite, wherein the outer shell (36) is except for an intermediate layer end (30, 34), which is in contact with the boss (26, 26'), covers the intermediate layer (28) such that the intermediate layer end (30, 34) of the intermediate layer (28) defines an intermediate layer ring (38, 38') exposed to an external environment, wherein the storage tank (10) is configured such that when gas diffuses through the liner (12) to the intermediate layer (28), the intermediate layer (28) directs the gas out of the exposed intermediate layer ring (38, 38').The storage tank (10) of claim 1, wherein the interdigitated web of the intermediate layer (28) has a porosity of greater than or equal to 15% to less than or equal to 85%.The storage tank (10) of claim 1, wherein the intermediate layer (28) further comprises a binder selected from the group consisting of styrene butadiene rubber, cellulose, polyvinylpyrrolidone, polyvinylidene fluoride, polypropylene carbonate, polyethylene carbonate, poly(cyclohexene propylene) carbonate, butylene carbonate, and combinations thereof.A method of making a storage tank (10) for a gas, the method comprising: coupling a boss (26, 26') to a liner (12) defining an interior chamber (24); applying an intermediate layer (28) over the liner (12) and over a portion of the boss (26, 26'), the intermediate layer (28) comprising an interlocking web comprising pores having a diameter greater than the size of a hydrogen molecule and less than or equal to 2 nm and a binder; and forming an outer shell (36) on the intermediate layer (28) except for an intermediate layer end (30, 34) in contact with the boss (26, 26') such that the intermediate layer end (30, 34) defines an intermediate layer ring (38, 38') exposed to an external environment, wherein the storage tank (10) is configured such that when gas diffuses through the liner (12) to the intermediate layer (28), the intermediate layer (28) directs the gas out of the exposed intermediate layer ring (38, 38').The method of claim 4, wherein coupling the boss (26, 26') to the liner (12) comprises threading the boss (26, 26') into the liner (12) through a thread on an inner surface of the boss (26, 26') and a complementary thread on an outer surface of the liner (12).The method of claim 4, wherein the intermediate layer (28) is formed by: forming a mixture of a precursor powder and the binder, casting a layer of the mixture onto a substrate, drying the layer to form the intermediate layer (28), and optionally calendering the intermediate layer (28).The method of claim 6, wherein the mixture comprises the precursor powder at a concentration of greater than or equal to 70 wt% to less than or equal to 95 wt% and the binder at a concentration of greater than or equal to 5 wt% to less than or equal to 30 wt%.The method of claim 6, wherein the precursor powder comprises carbon, silica, a polymer, an organometallic backbone, or combinations thereof, and the binder comprises styrene-butadiene rubber, cellulose, polyvinylpyrrolidone, polyvinylidene fluoride, polypropylene carbonate, polyethylene carbonate, poly(cyclohexenepropylene) carbonate, butylene carbonate, or combinations thereof.The method of claim 4, further comprising: applying an adhesive to the liner (12) and to the portion of the boss (26, 26') prior to applying the green interlayer (28).The method of claim 4, wherein the intermediate layer (28) comprises an additive binder and is in green form, and the method after forming further comprises: heating the storage tank (10) at a temperature of greater than or equal to 90°C to less than or equal to 160°C to remove at least a portion of the additive binder from the intermediate layer (28) present in green form and convert the intermediate layer (28) present in green form into a porous intermediate layer (28) having a relatively higher porosity than the intermediate layer (28) present in green form.

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