Hydrogen store

Abstract

The invention relates to a hydrogen store having little weight and low hydrogen permeability. The invention also relates to a combination material comprising a barrier material and a reinforcing material. The combination material can especially be used for walls in stores for molecular hydrogen.

Description

[0001] Hydrogen storage

[0002] The invention relates to a hydrogen storage device with low weight and low hydrogen permeability. The invention also relates to a combination material comprising a barrier material and a reinforcement material. The combination material can be used in particular as a wall in storage devices for molecular hydrogen.

[0003] State of the art

[0004] There are essentially four technologies for hydrogen storage:

[0005] • High pressure technology

[0006] • Cryogenics (liquid hydrogen)

[0007] • Cryo-compression technology

[0008] • Chemisorption or adsorption technology

[0009] High pressure is typically understood to mean up to 700 bar, see Materials 2019, 12, 1973, although up to 1000 bar is intended, see Int. J. Hydrogen Energy Mar. 2017, 42(11): 7254-62. Depending on the pressure, the required compression of the hydrogen consumes on the order of 10%-15% of the energy to be stored, see Int. J. of Hydrogen Energy 2021, 46(29), 15671-15690.

[0010] In steel design, the associated tanks typically have dimensions and working pressures of 220 mm diameter, 9.1 mm wall thickness, 280 bar working pressure or 470 mm diameter, 26 mm wall thickness, 410 bar working pressure, see International Journal of Hydrogen Energy 2017, 42(19), 13777-13788. A typical material issue arising for pressure vessels with metal involvement concerns hydrogen embrittlement of the metals, see International Int. J. of Hydrogen Energy 2021, 46(29), 15671-15690.

[0011] In the current Type IV hydrogen storage systems, mechanical strength is ensured by carbon fiber structures instead of metals to save weight (see Materials 2019, 12, 1973). These, in turn, must be bonded to a barrier material, a so-called "liner," e.g., by coating or lamination, whose hydrogen permeability is of course crucial. Another typical material issue for these hydrogen storage systems arises from the fact that the currently used composite materials can dissolve, especially during sudden discharge (mechanical and thermal causes: temperature changes during compression and decompression), see Int. J. Hydrogen Energy 2018, 43(9), 4671-4680. High-pressure technology is one of the generally favored storage technologies for mobile applications (see Materials 2019, 12, 1973).

[0012] N. Schramm, M. Neubert, MD Naumann, L. Ulke-Winter, L. Kroll and S. Nendel, Development of a carbon fiber reinforced annular pressure vessel for hydrogen storage, Fuel Cell Conference FC 3, Chemnitz, November 26-27, 2019, describes a prototype whose wall contains a 4mm thick PE liner, onto which a CFRP shell with an average thickness of 13.5mm is attached. The term "CFRP" stands for "carbon fiber reinforced plastic." Typical values ​​for the performance of such systems can be found in Yu Sun, Hong Lv, Wei Zhou, Cunman Zhang, Research on hydrogen permeability of polyamide 6 as the liner material for type IV hydrogen storage tank, International Journal of Hydrogen Energy 45 (2020) 24980 - 24990. For example, the article investigates the barrier effect of a 4mm thick PA6 (polycaprolactam, well-known trademark "Perlon") liner. The pressure dependence of the barrier effect is also taken into account. At room temperature and one-sided application of 25 MPa, the permeability is 5.6-10' 16 mol / (ms Pa), with one-sided loading with 50 MPa 1 ,4- 10 -16mol / (ms Pa). Accordingly, the H2 flow through a 4mm thick liner in the first case is 3.5-10' 6 mol / (m 2 s), in the second case 1 ,8- 10' 6 mol / (m 2 s). For comparison, Sun et al. estimate the maximum permissible permeability of a material suitable for liners according to ISO19881-2018 cited by these authors as 1.24' 10' 15 mol / (ms Pa). Sun et al. also describe a PA6 liner with a filler.

[0013] An overview of various "liner" materials is provided by RR Barth, KL Simmons, C. San Marchi, "Polymers for Hydrogen Infrastructure and Vehicle Fuel Systems: Applications, Properties, and Gap Analysis," Sandia Report SAND2013-8904 (Sandia National Laboratories, USA). However, only high-density polyethylene (HDPA) and polyamide (PA) are essentially used; see Winoj Balasooriya, Clara Clute, Bernd Schrittsser, and Gerald Pinter, "A Review on Applicability, Limitations, and Improvements of Polymeric Materials in High-Pressure Hydrogen Gas Atmospheres," Polymer Reviews, Vol. 62, No. 1, 2022, 175-209.

[0014] The second technology mentioned above, cryogenics, has the disadvantage that at the beginning of hydrogen storage, considerably more energy is required to liquefy the hydrogen than with high-pressure technology, up to 40% of the stored energy, and the temperature must be kept below -253°C, see Int. J. Hydrogen Energy Mar. 2017, 42(11): 7254-62. Pressure vessels with an additional thermal insulation layer are used. This technology is interesting for stationary systems, where this insulation layer can be designed in such a way that the losses due to evaporation, which occur as a result of the unavoidable heat inflow, are very low thanks to a safety valve ("boil-off"), see Materials 2019, 12, 1973, or for applications where high energy density is crucial, e.g. space travel, see Int. J. Hydrogen Energy Mar. 2017, 42(11): 7254-62, or aviation, see Materials 2019, 12, 1973.

[0015] In cryogenic compression technology, the pressure vessel described above is built in such a way that it can withstand very high pressures of up to 300 bar, for example. This significantly reduces boil-off losses compared to cryogenic technology (at the same temperature), see Int. J. Hydrogen Energy Mar. 2017, 42(11): 7254-62. Cryogenic compression storage can also be operated at temperatures that are low but above the boiling point of hydrogen, see Int. J. Hydrogen Energy Mar. 2017, 42(11): 7254-62. Compared to storage at room temperature, this takes advantage of the fact that for gases at the same pressure the amount of substance is proportional to the inverse of the temperature, thus increasing the amount of stored hydrogen per volume. Such pressure vessels can be built using carbon fiber technology, with a corresponding "liner", see Int. J. Hydrogen Energy Mar. 2017, 42(11): 7254-62.

[0016] There are various approaches in the field of chemisorption or adsorption. One involves the binding of hydrogen to magnesium under specific pressure and temperature conditions and the corresponding storage as magnesium hydride, see Materials 2019, 12, 1973. In addition to the process-related energy losses, there is also the standard enthalpy of formation of the hydride, which, however, is only about 10% of the combustion enthalpy of hydrogen. Storage takes place in low-pressure containers, e.g., at 15 bar, see Int. J. Hydrogen Energy 2010, 35(12), 6311-6322, where the pressure is intended to counteract the dissociation of the hydride.

[0017] Brief description of the invention

[0018] One object of the invention is to improve hydrogen storage. This object is achieved by the subject matter of the patent claims.

[0019] The present invention relates to a hydrogen storage device, in particular a mobile hydrogen storage device, for example for motor vehicles (in particular for a passenger car, for a truck, for a bus or for a motorcycle), for rail vehicles (in particular for a passenger train or for a freight train), for aircraft (in particular for airplanes or helicopters), or for watercraft (in particular for passenger ships, container ships or tankers). A mobile hydrogen storage device can in particular be a hydrogen tank or a sorption storage device. In the course of efforts to achieve extensive independence from fossil fuels such as coal, oil or gas, the use of hydrogen is a future technology with great growth potential.However, especially for mobile hydrogen storage systems, which can be used in all types of vehicles, it is crucial to keep the weight of the hydrogen storage systems low to ensure the technology's high efficiency. Mobile hydrogen storage systems with a high weight are disadvantageous because the weight of the hydrogen storage system must always be transported, which results in increased energy consumption.

[0020] Against this background, the present invention provides lightweight hydrogen storage devices. The hydrogen storage devices of the invention comprise a combination material which includes a barrier material and a reinforcing material. The reinforcing material can in particular be a fibrous material. The reinforcing material can in particular comprise or consist of carbon fibers, silicon carbide fibers, aluminum oxide fibers, silicon oxide fibers or combinations of two or more thereof. Carbon fibers, silicon fibers, etc. means in particular that carbon, silicon carbide, etc. represents the respective main component, i.e. their proportion in the total weight of the fiber is more than 50 wt.%, more preferably more than 60 wt.%, more preferably more than 70 wt.%, more preferably more than 80 wt.%, more preferably more than 90 wt.%, more preferably more than 95 wt.%, more preferably more than 98 wt.%, more preferably more than 99 wt.-%, more preferably 100 wt% or substantially 100 wt%; in addition to carbon, silicon carbide, etc., the fibers may in particular contain one or more components selected from the group consisting of oxygen, boron, titanium, zirconium, nitrogen, and combinations of two or more thereof.

[0021] The reinforcing material may also include glass fibers, such as those used for glass fiber reinforced plastics; the corresponding glasses are generally referred to as E-glass, S-glass, R-glass, M-glass, C-glass, ECR-glass, D-glass, AR-glass, or Q-glass.

[0022] The reinforcing material can be a fiber-reinforced plastic, for example a carbon fiber-reinforced plastic (CFRP) or a glass fiber-reinforced plastic (GFRP). A fiber-reinforced plastic is a material made of reinforcing fibers and a plastic matrix. The fiber volume fraction (p) is preferably in a range from 50 to 70 vol.%, in particular from 55 to 65 vol.% or approximately 60 vol.%. The fiber volume fraction (p) is preferably at least 50 vol.%, at least 55 vol.%, or at least 60 vol.%. The fiber volume fraction (p) is preferably at most 70 vol.%, at most 65 vol.%, or preferably at most 60 vol.%. The plastic matrix preferably comprises an epoxy resin or consists of an epoxy resin.

[0023] Short description of the characters

[0024] Figure 1 shows schematically a predominantly superellipsoidal shaped hydrogen storage device 11 with a wall made of a combination material.

[0025] Figure 2 schematically shows a predominantly superellipsoidal shaped hydrogen storage device 21 with a wall that partially consists of a combination material.

[0026] Figure 3 schematically shows two bottle-shaped hydrogen storage devices 31a and 31b with a wall consisting entirely or partially of a combination material.

[0027] Detailed description of the invention

[0028] In one aspect, the invention relates to a hydrogen storage device, in particular a mobile hydrogen storage device, preferably a mobile hydrogen tank. The present invention provides a hydrogen storage device with a particularly low weight, which (more precisely: its wall) nevertheless has a particularly low hydrogen permeability.

[0029] The hydrogen storage device of the invention preferably has a cavity in which the hydrogen can be stored. The cavity is enclosed by a wall. The wall is intended to prevent the hydrogen from escaping. The thickness of the wall is in particular in a range from 15 mm to 50 mm, for example from 20 mm to 45 mm, from 25 mm to 40 mm, or from 30 to 35 mm. The thickness of the wall should not be too small. Otherwise, the unwanted losses of hydrogen could be too great. Preferably, the thickness of the wall is at least 15 mm, at least 20 mm, at least 25 mm, or at least 30 mm. However, the thickness of the wall should not be too great either. Otherwise, an unwanted increase in the weight of the hydrogen storage device occurs. This plays a particularly important role in mobile hydrogen storage devices, for example, in hydrogen tanks.Preferably, the thickness of the wall is at most 50 mm, at most 45 mm, at most 40 mm, or at most 35 mm.

[0030] The wall has in particular at least one opening, for example at least one inlet and / or at least one outlet. The inlet and / or the outlet can be provided in two separate openings or in a common opening. The inlet serves to fill the cavity with hydrogen. Hydrogen can leave the cavity through the outlet, for example to reach an energy converter, in particular a fuel cell. Hydrogen can serve as a fuel from which the energy converter can generate electrical energy, for example, in particular to power a vehicle. The openings in the wall are preferably provided with valves. This allows the entry of the hydrogen into the cavity and the exit of the hydrogen from the cavity to be controlled in a targeted manner.

[0031] A hydrogen storage device, for example a hydrogen tank, is in particular a container with a hollow space in which hydrogen can be stored. The invention relates to such a container with a wall comprising a barrier material. The container or its wall can in particular have an inlet and / or an outlet. The container is in particular a hydrogen storage device (preferably a mobile hydrogen storage device or hydrogen tank) or can be used as a hydrogen storage device (preferably as a mobile hydrogen storage device or hydrogen tank). The container or its wall can consist of the barrier material. However, the wall preferably comprises one or more further materials, in particular one or more reinforcing materials.The combination material comprising or consisting of barrier and reinforcement material can be present either as a material composite or as a composite material, in particular also as a laminar structure. A material composite is therefore in particular a layered composite. The combination material of the invention is preferably a material composite, in particular a layered composite, preferably comprising or consisting of one or more barrier material layers and one or more reinforcement material layers. In contrast to a material composite, a composite material is understood in particular to be a combination material that does not have such a layered structure or any other macroscopically recognizable combination structure, for example a dispersion-reinforced plastic or a glass ceramic. The use of the reinforcement materials can be adapted to the loading conditions in the container.

[0032] In some embodiments of the invention, the entire wall of the hydrogen storage device comprises a combination material comprising or consisting of a barrier material and a reinforcement material. It is also possible for the entire wall to be made of a combination material comprising or consisting of a barrier material and a reinforcement material. The advantage of such configurations is the particular mechanical stability of the wall. However, such a configuration can be disadvantageous, particularly when very high demands for particularly low weight are placed on it.

[0033] In some embodiments of the invention, only a portion of the wall comprises a combination material comprising or consisting of a barrier material and a reinforcement material. It is also possible for a portion of the wall to consist of a combination material comprising or consisting of a barrier material and a reinforcement material. The portion of the wall that does not comprise a combination material can, for example, consist of the barrier material. Such a configuration allows for additional weight savings. Reinforcement material can be omitted, in particular, at those points on the wall where the barrier material already has a comparatively high level of stability due to its geometric configuration.

[0034] The wall preferably comprises, at least in places or over the entire wall, a barrier material and a reinforcing material, for example a fibrous or fibrous reinforcing material, in particular comprising or consisting of carbon fibers, for example a carbon fiber braid, and / or silicon carbide fibers and / or aluminum oxide or silicon oxide fibers. In embodiments of the invention, the container or the wall comprises a barrier material (in particular with a cylindrical basic shape) as a winding core for a fiber braid, in particular comprising or consisting of carbon fibers and / or silicon carbide fibers. The container can be a stationary container or a mobile container.Mobile containers are, for example, tanks for vehicles, in particular for motor vehicles (in particular for a passenger car, for a lorry, for a bus or for a motorcycle), for rail vehicles (in particular for a passenger train or for a freight train), for aircraft (in particular for airplanes or helicopters), or for watercraft (in particular for passenger ships, container ships or tankers).

[0035] The term “hydrogen tank” refers in particular to a mobile hydrogen storage device, for example for vehicles.

[0036] The container of the invention, in particular, has a cavity enclosed by a wall. The thickness of the wall is in particular in a range from 15 mm to 50 mm, for example from 20 mm to 45 mm, from 25 mm to 40 mm, or from 30 to 35 mm. Preferably, the thickness of the wall is at least 15 mm, at least 20 mm, at least 25 mm, or at least 30 mm. Preferably, the thickness of the wall is at most 50 mm, at most 45 mm, at most 40 mm, or at most 35 mm.

[0037] The thickness of the wall can be uniform across the entire wall. It is also possible to make the wall thicker in those areas that require special reinforcement than in those areas that do not. Such deviations in the wall thickness can be achieved, for example, by adjusting the thickness of the barrier material accordingly. However, the thickness of the barrier material is preferably not a spatially variable size, since otherwise "diffusion holes" would be created, i.e. areas with greater permeability to hydrogen. The aforementioned variations in thickness are therefore preferably based on providing a thicker layer of reinforcement material or on providing a layer of reinforcement material at all.

[0038] The difference between the maximum and minimum thickness of the wall can also be referred to as the total thickness variation of the wall. The total thickness variation of the wall is preferably in a range from 0.1 to 10 mm, for example from 0.2 to 5.0 mm or from 0.5 to 2.0 mm. The total thickness variation of the wall can be, for example, at least 0.1 mm, at least 0.2 mm, or at least 0.5 mm. The total thickness variation of the wall can be, for example, at most 10 mm, at most 5.0 mm, or at most 2.0 mm.

[0039] The wall has an inner surface and an outer surface. The inner surface is in contact with the cavity and, if appropriately filled, also with the hydrogen contained therein. The outer surface of the wall is directed outward and is separated from the cavity and any hydrogen contained therein by the thickness of the wall.

[0040] According to this construction, the wall in any case has an inner layer. The inner layer is, in particular, the layer that provides the inner surface of the wall. The wall can consist entirely or in certain regions of the inner layer, so that the inner layer provides both the inner surface and the outer surface of the wall, for example, in regions where additional reinforcement is not required. In completely single-layer embodiments, a composite material is preferably used that comprises or consists of the barrier material and the reinforcement material. Such a composite material can assume the function of both the barrier material and the reinforcement material.

[0041] Preferably, however, the wall also has an outer layer in addition to the inner layer. In such embodiments, the inner surface of the wall is provided by the inner layer, and the outer surface of the wall is provided by the outer layer.

[0042] Preferably, the inner layer comprises or consists of a barrier material.

[0043] The inner layer of the invention is, in particular, a sheet-like material and thus not fibrous. A fibrous design of the inner layer would be associated with an increase in hydrogen permeability, which is to be avoided according to the invention. Rather, the hydrogen permeability should be low. Therefore, the inner layer is preferably not fibrous. Instead, a sheet-like design of the inner layer is preferred. The inner layer is preferably layered, for example in the form of a film or layer. The inner layer is therefore preferably in the form of a layer, in particular in the form of a film or layer. The inner layer is preferably substantially free of pores, gaps, and / or holes. The inner layer is preferably a closed layer.

[0044] The inner layer preferably has a thickness in a range from 0.02 mm to 5.0 mm, for example from 0.05 to 3.5 mm, from 0.1 to 2.5 mm, from 0.2 to 2.0 mm, or from 0.5 to 1.2 mm. The thickness of the inner layer is preferably at least 0.02 mm, at least 0.05 mm, at least 0.1 mm, at least 0.2 mm, or at least 0.5 mm. The thickness of the inner layer is preferably at most 5.0 mm, at most 3.5 mm, at most 2.5 mm, at most 2.0 mm, or at most 1.2 mm.

[0045] The difference between the largest thickness and the smallest thickness of the inner layer can also be referred to as the total thickness variation of the inner layer. The total thickness variation of the inner layer is preferably in a range from 0.005 mm to 1.0 mm, for example from 0.01 to 0.75 mm, from 0.02 to 0.5 mm or from 0.05 to 0.25 mm. The total thickness variation of the inner layer is preferably at least 0.005, at least 0.01 mm, at least 0.02 mm or at least 0.05 mm. The total thickness variation of the inner layer is preferably at most 1.0 mm, at most 0.75 mm, at most 0.5 mm or at most 0.25 mm.

[0046] The outer layer preferably comprises or consists of a reinforcing material. The outer layer preferably has a thickness in a range from 10 mm to 35 mm, for example from 15 to 30 mm or from 20 to 25 mm. The thickness of the outer layer is preferably at least 10 mm, at least 15 mm, or at least 20 mm. The thickness of the outer layer is preferably at most 35 mm, at most 30 mm, or at most 25 mm.

[0047] The difference between the largest and smallest thicknesses of the outer layer can also be referred to as the total thickness variation of the outer layer. The total thickness variation of the outer layer is preferably in a range from 0.1 mm to 10 mm, for example from 0.2 to 5.0 mm or from 0.5 to 2.5 mm. The total thickness variation of the outer layer is preferably at least 0.1 mm, at least 0.2 mm, or at least 0.5 mm. The total thickness variation of the outer layer is preferably at most 10 mm, at most 5.0 mm, or at most 2.5 mm.

[0048] The volume of the cavity is in particular in a range from 20 liters to 100,000 liters, preferably 50 liters to 50,000 liters, for example from 100 to 25,000 liters, from 200 to 10,000 liters, from 500 to 5,000 liters, or from 1,000 to 2,000 liters. The volume of the cavity is preferably at least 20 liters, more preferably at least 50 liters, for example at least 100 liters, at least 200 liters, at least 500 liters, or at least 1,000 liters. The volume of the cavity is preferably at most 100,000 liters, more preferably at most 50,000 liters, for example at most 25,000 liters, at most 10,000 liters, at most 5,000 liters, or at most 2,000 liters.

[0049] The container and in particular the boundary of the cavity, i.e. the wall, can have various shapes. A superellipsoidal or predominantly superellipsoidal shape is preferred, as shown by way of example in Figures 1 and 2. A superellipsoidal or predominantly superellipsoidal shape is particularly advantageous for withstanding high pressures. The same applies to a bottle-shaped design, which is also part of the present invention. A bottle-shaped design is shown, for example, in Figure 3. In principle, complex shapes are possible (and in practice also likely). The transitions from one shape to another are also often fluid. For example, a basic cylindrical shape that has a curvature on one side can be referred to as bottle-shaped.

[0050] The present invention particularly relates to a hydrogen storage device with a wall enclosing a cavity. In a preferred embodiment, the wall consists of a combination material, in particular a material composite comprising an inner barrier layer (i.e., facing the cavity) comprising or consisting of a barrier material and an outer reinforcement layer comprising or consisting of a reinforcement material. The reinforcement layer can, in particular, be provided continuously around the barrier layer.

[0051] The hydrogen storage device may comprise one or more valves, for example, two valves. The valves may be provided, in particular, on opposite sides of the hydrogen storage device, for example, on the short sides of the hydrogen storage device.

[0052] The hydrogen storage device or its wall can, in particular, be designed such that the shape of the wall is based on a cylinder or a basic cylinder. Based on a basic cylinder, various shapes can be realized, for example, a superellipsoidal or predominantly superellipsoidal shape or a bottle shape. In a superellipsoidal or predominantly superellipsoidal shape, two short sides are provided, which are entirely or partially convexly curved, whereby the center of one short side can be a flat surface. In a bottle shape, one of the short sides is always designed as a base on which the bottle-shaped hydrogen storage device can be placed. The other short side can be convexly curved in any desired manner.In a bottle-shaped embodiment, a valve is preferably provided on the short side, which can be convexly curved in any desired manner, which can be formed in particular at the end of the hydrogen storage device opposite the base. Bottle-shaped embodiments preferably contain only one valve.

[0053] In a single-valve solution, the valve can in particular be provided as both an inlet and an outlet. In a two-valve solution, for example in a superellipsoidal or predominantly superellipsoidal shape of the hydrogen storage device with two opposite convexly curved short sides, the two valves can in particular be provided on the two short sides, i.e. one valve on each of the two short sides. In a multi-valve solution such as a two-valve solution, it is possible, for example, to provide one of the valves as the inlet and another of the valves as the outlet. However, this is not necessarily the case. Even in a multi-valve solution such as a two-valve solution, it is possible to provide one of the valves as both an inlet and an outlet. The additional valve (in a two-valve solution) or the additional valves (in an embodiment with three or more valves) can also be designed as an inlet and / or an outlet.It is also possible to design one or more of the valves as a safety valve. A safety valve can, for example, be equipped with a pressure sensor and open when a pressure threshold is exceeded to prevent the buildup of undesirable overpressure. "Unwanted overpressure" is understood to mean, in particular, a pressure that can be accompanied by damage to the integrity of the wall of the hydrogen storage device, which can lead to a gradual or even spontaneous loss of significant quantities of hydrogen from the cavity. Spontaneous loss can also pose the risk of damage to nearby objects or parts of buildings or of injury to nearby persons. The buildup of undesirable overpressure should therefore be avoided if possible.

[0054] Not to be confused with such undesirable overpressure is the target overpressure, which is desired for hydrogen storage and can be specifically adjusted. To withstand such a target overpressure, high demands are placed on the material of the hydrogen storage tank's walls.

[0055] The container of the invention is particularly suitable for storing hydrogen. For this purpose, the container must be able to withstand high or very high pressures, as described above. Preferably, the container can withstand a pressure of up to 10 bar, up to 25 bar, up to 50 bar, up to 100 bar, up to 200 bar, up to 300 bar, up to 400 bar, up to 500 bar, up to 600 bar, up to 700 bar, up to 800 bar, up to 900 bar, up to 1000 bar, up to 1200 bar, or up to 1500 bar. Preferably, the wall of the hydrogen storage device comprises a combination material, in particular a composite material or a material composite, or the wall consists of a combination material, in particular a composite material or a material composite.

[0056] The present invention also relates to a combination material, in particular a composite material or a material composite, in particular a composite material or a material composite comprising or consisting of a barrier material and a reinforcing material.

[0057] The density of the reinforcing material is preferably in a range of 1.4 to 4.5 g / cm 3 , for example 1.5 g / cm 3 up to 3.5 g / cm 3 , from 1.6 to 3.0 g / cm 3 or from 1.7 to 2.5 g / cm 3 . The density of the reinforcing material is preferably at least 1.4 g / cm 3 , at least 1.5 g / cm 3 , at least 1.6 g / cm 3 or at least 1.7 g / cm 3 . The density of the reinforcing material is preferably at most 4.5 g / cm 3 , maximum 3.5 g / cm 3 , maximum 3.0 g / cm 3 , or a maximum of 2.5 g / cm 3 .

[0058] Also important is the ratio of the thermal expansion coefficients of the barrier material compared to the reinforcement material. The difference in the average coefficient of thermal expansion (GTE) of the reinforcement material and the barrier material in a range from 20°C to 300°C is preferably in a range from 0.0 to 10.0 ppm / K, from 0.1 to 7.5 ppm / K, from 0.2 to 5.0 ppm / K, from 0.5 to 2.5 ppm / K, or from 1.0 to 2.0 ppm / K. The difference between the GTE of the reinforcement material and the GTE of the barrier material is preferably at most 10.0 ppm / K, at most 7.5 ppm / K, at most 5.0 ppm / K, at most 2.5 ppm / K, or at most 2.0 ppm / K. The difference between the GTE of the reinforcement material and the GTE of the barrier material can be, for example, about 0.0 ppm / K, at least 0.1 ppm / K, at least 0.2 ppm / K, at least 0.5 ppm / K, or at least 1.0 ppm / K.The term “difference” means in particular the difference between the GTE of the reinforcement material and the GTE of the barrier material or the amount of this difference.

[0059] When reference is made to "GTE" in this disclosure, it means the average coefficient of linear thermal expansion in a range of 20°C to 300°C, unless otherwise stated. This applies to both measured and calculated values.

[0060] The reinforcing material serves in particular for mechanical reinforcement and therefore preferably has excellent mechanical properties. The reinforcing material can, for example, have a tensile strength in a range from 1.5 GPa to 8.0 GPa, for example from 2.0 to 6.0 GPa, from 2.5 to 5.0 GPa, or from 3.0 to 4.0 GPa. The tensile strength of the reinforcing material is preferably at least 1.5 GPa, at least 2.0 GPa, at least 2.5 GPa, or at least 3.0 GPa. The tensile strength of the reinforcing material can, for example, be at most 8.0 GPa, at most 6.0 GPa, at most 5.0 GPa, or at most 4.0 GPa.

[0061] The reinforcement material can, for example, have a modulus of elasticity of 120 GPa to 500 GPa, for example, from 150 to 450 GPa, from 170 to 420 GPa, from 200 to 400 GPa, from 220 to 380 GPa, or from 250 to 350 GPa. The modulus of elasticity of the reinforcement material can, for example, be at least 120 GPa, at least 150 GPa, at least 170 GPa, at least 200 GPa, at least 220 GPa, or at least 250 GPa. The modulus of elasticity of the reinforcement material can, for example, be at most 500 GPa, at most 450 GPa, at most 420 GPa, at most 400 GPa, at most 380 GPa, or at most 350 GPa.

[0062] Tensile strength, Young's modulus, and other material properties can be determined using a method known as a tensile test (also called a tensile test). The result of the tensile test is the stress-strain diagram. From this, the technical material parameters can be derived. Depending on the material being tested, the tensile test is described in various standards that are familiar to those skilled in the art. The determination of the tensile properties of ceramic fibers can be carried out, in particular, according to DIN EN 1007-4:2004-08.

[0063] The reinforcing material may, for example, have an average coefficient of thermal expansion (GTE) in a range from -1.0 to 20.0 ppm / K, from -0.5 to 15.0 ppm / K, or from -0.2 to 12.0 ppm / K. The GTE may, for example, be at least -1.0 ppm / K, at least -0.5 ppm / K, or at least -0.2 ppm / K. The GTE may, for example, be at most 20.0 ppm / K, at most 15.0 ppm / K, or at most 12.0 ppm / K.

[0064] For fibrous reinforcing materials, the GTE in the longitudinal direction can differ from the GTE in the transverse direction. In particular, the GTE in the longitudinal direction can be close to zero or even negative. In the transverse direction, however, the GTE can be significantly higher than in the longitudinal direction.

[0065] The GTE in the transverse direction is preferably in a range from 2.0 to 20.0 ppm / K, from 5.0 to 15.0 ppm / K or from 7.5 to 12.5 ppm / K. The GTE in the transverse direction can be, for example, at least 2.0 ppm / K, at least 5.0 ppm / K or at least 7.5 ppm / K. The GTE in the transverse direction can be, for example, at most 20.0 ppm / K, at most 15.0 ppm / K or at most 12.5 ppm / K. The GTE in the longitudinal direction is preferably in a range from -1.0 to 1.0 ppm / K, from -0.5 to 0.5 ppm / K or from -0.2 to 0.0 ppm / K. The GTE in the longitudinal direction can be, for example, at least -1.0 ppm / K, at least -0.5 ppm / K or at least -0.2 ppm / K. For example, the GTE in the longitudinal direction may be no more than 1.0 ppm / K, no more than 0.5 ppm / K or no more than 0.0 ppm / K.

[0066] The difference between the GTE of the reinforcement material in the transverse direction and the GTE of the barrier material is preferably in a range from 0.0 to 10.0 ppm / K, from 0.1 to 7.5 ppm / K, from 0.2 to 5.0 ppm / K, from 0.5 to 2.5 ppm / K, or from 1.0 to 2.0 ppm / K. The difference between the GTE of the reinforcement material in the transverse direction and the GTE of the barrier material is preferably at most 10.0 ppm / K, at most 7.5 ppm / K, at most 5.0 ppm / K, at most 2.5 ppm / K, or at most 2.0 ppm / K. The difference between the GTE of the reinforcement material in the transverse direction and the GTE of the barrier material can be, for example, approximately 0.0 ppm / K, at least 0.1 ppm / K, at least 0.2 ppm / K, at least 0.5 ppm / K, or at least 1.0 ppm / K. "Difference" is understood to mean, in particular, the difference between the GTE of the reinforcement material in the transverse direction and the GTE of the barrier material or the amount of this difference.

[0067] The difference between the GTE of the barrier material and the GTE of the reinforcement material in the longitudinal direction is preferably in a range from 1.0 to 12.5 ppm / K, from 2.5 to 10.0 ppm / K or from 5.0 to 7.5 ppm / K. The difference between the GTE of the barrier material and the GTE of the reinforcement material in the longitudinal direction can, for example, be at least 1.0 ppm / K, at least 2.5 ppm / K or at least 5.0 ppm / K. The difference between the GTE of the barrier material and the GTE of the reinforcement material in the longitudinal direction can, for example, be at most 12.5 ppm / K, at most 10.0 ppm / K or at most 7.5 ppm / K. “Difference” is to be understood in particular as the difference between the GTE of the barrier material and the GTE of the reinforcement material in the longitudinal direction or the amount of this difference.

[0068] The combination material of the invention, in particular the composite material or material composite, can, for example, comprise a barrier material and a reinforcement material or consist of a barrier material and a reinforcement material. The reinforcement material can, in particular, be selected from the group consisting of carbon fibers, silicon carbide fibers, aluminum oxide fibers, silicon oxide fibers, and combinations of two or more thereof.

[0069] The combination material can, for example, be present as a material composite, in particular in the form of a layered composite. In particular, a core (e.g., based on a basic cylindrical shape) and a fiber mesh surrounding the core can be provided, for example, a fiber mesh made of carbon fibers and / or silicon carbide fibers and / or oxide fibers. The core can also be referred to as an inner layer and, for example, comprise or consist of a barrier material.

[0070] The invention also provides barrier materials which (i) have a higher hydrogen impermeability than the plastics currently used, which (ii) are suitable for composite with fibrous reinforcing materials, in particular carbon fiber structures, with regard to thermal expansion, which (iii) contribute little to the weight of the overall system and / or which (iv) have a high fracture toughness.

[0071] The barrier material is particularly designed as a sheet material. A sheet material is flat and thus differs from a fiber. The sheet material described herein is particularly a film or a layer.

[0072] The barrier material of the invention is, in particular, not a fibrous material. Configuring it as a fibrous material would increase hydrogen permeability, which is to be avoided according to the invention. Rather, the hydrogen permeability should be low. Therefore, the barrier material is preferably not fibrous. Rather, a flat design of the barrier material is preferred. The barrier material is preferably layered. The barrier material is preferably a layered material or layered material, for example a film or layer. The barrier material is therefore preferably in the form of a layer, in particular as a film or layer. The barrier layer is preferably substantially free of pores, gaps, and / or holes. The barrier layer is preferably a closed layer.

[0073] The barrier material of the invention preferably has a particularly high hydrogen impermeability. In other words, the hydrogen permeability of the barrier material is preferably particularly low.

[0074] The 10-logarithm of the H2 permeability per mol / (m s-Pa) of the wall of the hydrogen storage device according to the invention, the combination material according to the invention and / or the barrier material according to the invention is, in particular at a temperature of 473 K, preferably less than -20,000, more preferably less than -20,100, more preferably less than -20,200, more preferably less than -20,300, more preferably less than -20,400, more preferably less than -20,500, more preferably less than -20,600, more preferably less than -20,700, more preferably less than -20,800, more preferably less than -20,900, more preferably less than -21,000, more preferably less than -21,250, more preferably less than -21,500, more preferably less than -21,750, more preferably less than -22,000, more preferably less than -22,250, more preferably less than -22,500, more preferably less than -22,750, more preferably less than -23,000,more preferably less than -23,250, more preferably less than -23,500, more preferably less than -23,750, more preferably less than -24,000. The base 10 logarithm of the H2 permeability per mol / (ms Pa) of the wall of the hydrogen storage device according to the invention, the combination material according to the invention, and / or the barrier material according to the invention can be, for example, more than -29,000, more than -28,500, more than -28,000, more than -27,500, more than -27,000, more than -26,500, more than -26,000, more than -25,500, more than -25,000, or more than -24,500, in particular at a temperature of 473 K.

[0075] The logarithm of the H2 permeability per molZ (ms Pa) of the wall of the hydrogen storage device according to the invention, the combination material according to the invention and / or the barrier material according to the invention can, in particular at a temperature of 473 K, for example, be in a range from more than -29,000 to less than -20,000, from more than -29,000 to less than -20,100, from more than -29,000 to less than -20,200, from more than -29,000 to less than -20,300, from more than -29,000 to less than -20,400, from more than -29,000 to less than -20,500, from more than -29,000 to less than -20,600, from more than -29,000 to less than -20,700, from more than -29,000 to less than -20,800, from more than -29,000 to less than -20,900, from more than -29,000 to less than -21,000, from more than -29,000 to less than -21,250, from more than -29,000 to less than -21,500, from more than -29,000 to less than -21,750, from more than -28,500 to less than -22,000, from more than -28,000 to less than -22,250, from more than -27,500 to less than -22,500, from more than -27,000 to less than -22,750, from more than -26,500 to less than -23,000, from more than -26,000 to less than -23,250, from more than -25,500 to less than -23,500, from more than -25,000 to less than -23,750, or from more than -24,500 to less than -24,000. The H2 permeability per mol / (ms Pa) can be measured as described in Journal of Non-Crystalline Solids 394-395 (2014) 43-49.

[0076] The average coefficient of thermal expansion (CTE) of the barrier material in a range from 20°C to 300°C is preferably in a range from 3.5 to 9.5 ppm / K, from 4.0 to 9.0 ppm / K, from 4.5 to 8.5 ppm / K, or from 5.0 to 8.0 ppm / K. The CTE of the barrier material is preferably at least 3.5 ppm / K, at least 4.0 ppm / K, at least 4.5 ppm / K, or at least 5.0 ppm / K. The CTE of the barrier material is preferably at most 9.5 ppm / K, at most 9.0 ppm / K, at most 8.5 ppm / K, or at most 8.0 ppm / K. The CTE of the barrier material can in particular be calculated or determined according to DIN ISO 7991: 1998-02. The CTE of the reinforcement material can be determined according to DIN EN 16245: 2013-08. The density of the barrier material is preferably 2.70 g / cm 3 , more preferably not more than 2.65 g / cm 3 , even more preferably not more than 2.60 g / cm 3 . The density of the barrier material can, for example, be at least 2.20 g / cm3 , at least 2.25 g / cm 3 , or at least 2.30 g / cm 3 The density of the barrier material can, for example, be in a range of 2.20 to 2.70 g / cm 3 , from 2.25 to 2.65 g / cm 3 or from 2.30 to 2.60 g / cm 3 lay.

[0077] The fracture toughness of the barrier material is described by the K1c, which is measured according to the S EP B method as described in Journal of the European Ceramic Society 37 (2017) 4243-4257.

[0078] Glass is excellently suited as part of the combination material of the invention, especially the composite material, especially as a barrier material. However, the glass should have low hydrogen permeability. Furthermore, the CTE of the glass should not deviate too much from the CTE of the reinforcement material of the combination material. The use of glass as part of the combination material can allow the formation of a particularly thin wall with sufficiently low hydrogen permeability, thus enabling the creation of particularly lightweight hydrogen storage devices and hydrogen tanks, which is advantageous for vehicle tanks of all types for energy efficiency reasons.

[0079] Glass is also advantageous for other reasons. In particular, hydrogen-induced material aging is minimal. Furthermore, combination materials, especially composites of glass on the one hand and carbon, silicon carbide, and / or oxide fibers on the other, can be produced in which delamination does not occur, or only to a limited extent.

[0080] Particularly when used in or as a barrier material, the glass of the invention is preferably in the form of a sheet material and thus not in fibrous form. A fibrous design of the glass of the invention would be associated with an increase in hydrogen permeability, which is to be avoided according to the invention. Rather, the hydrogen permeability should be low. Therefore, the glass of the invention is preferably not in fibrous form. Instead, a sheet-like design of the glass of the invention is preferred. The glass of the invention is preferably in the form of a layer, for example in the form of a glass layer or a glass film. The glass of the invention is therefore preferably in the form of a glass layer, in particular in the form of a glass film. The use of the term “film” does not imply any limitation on the layer thickness.

[0081] The invention relates to a glass article comprising or consisting of the glass of the invention. The glass article of the invention is preferably not fibrous. Rather, a flat design of the glass article is preferred. The glass article is preferably layered, for example in the form of a glass layer or a glass film. The glass article is therefore preferably in the form of a glass layer, in particular in the form of a glass film. The glass article is preferably a glass layer or a glass film.

[0082] The glass article preferably has a thickness in a range from 0.02 mm to 5.0 mm, for example from 0.05 to 3.5 mm, from 0.1 to 2.5 mm, from 0.2 to 2.0 mm, or from 0.5 to 1.2 mm. The thickness of the glass article is preferably at least 0.02 mm, at least 0.05 mm, at least 0.1 mm, at least 0.2 mm, or at least 0.5 mm. The thickness of the glass article is preferably at most 5.0 mm, at most 3.5 mm, at most 2.5 mm, at most 2.0 mm, or at most 1.2 mm.

[0083] The difference between the largest thickness and the smallest thickness of the glass article can also be referred to as the total thickness variation of the glass article. The total thickness variation of the glass article is preferably in a range from 0.005 mm to 1.0 mm, for example from 0.01 to 0.75 mm, from 0.02 to 0.5 mm or from 0.05 to 0.25 mm. The total thickness variation of the glass article is preferably at least 0.005, at least 0.01 mm, at least 0.02 mm or at least 0.05 mm. The total thickness variation of the glass article is preferably at most 1.0 mm, at most 0.75 mm, at most 0.5 mm or at most 0.25 mm.

[0084] The invention also relates to a glass comprising the following components in the specified proportions (in mol%):

[0085] Table 1 It has been found that glass is particularly suitable as a barrier material if it contains a minimum amount of U2O and / or MgO. Furthermore, a minimum amount of four-coordinate boron is advantageous, but not a three-coordinate boron content. Therefore, the glasses of the invention contain, based on the respective molar fractions, at least as much alkali metal oxides and alkaline earth metal oxides as Al2O3 and B2O3 ((Zr2O + ZrO) > (Al2O3 + B2O3)).

[0086] The problem is preferably further solved by a targeted combination of stoichiometric glasses, i.e., glasses that also exist as crystals in the same stoichiometry and whose properties can be assumed to be very similar due to the generally identical topology of the components—as verified in the literature using NMR measurements or similar methods—for both glass and crystal. For this purpose, stoichiometric glasses are selected whose mixture makes behavior achievable in the sense of solving the problem according to the invention. In this application, these stoichiometric glasses are also referred to as "constituent phases."

[0087] It is not a new concept to describe glasses based on their constituent phases (see, for example, EP 3473 604 B1 and DE 102017 102 482 B4). By specifying the basic glasses, conclusions can be drawn about the chemical structure of a glass (cf. Conradt R: "Chemical structure, medium range order, and crystalline reference state of multicomponent oxide liquids and glasses," in Journal of Non-Crystalline Solids, Volumes 345-346, 15 October 2004, Pages 16-23).

[0088] The present invention thus also relates to a glass having a composition characterized by the following glass-constituent phases; this basic system defined by the constituent phases is restricted according to the invention by the specified composition ranges:

[0089] Table 2

[0090] The basic systems refer explicitly to the respective constituent phases mentioned and not to the simple oxides.

[0091] Furthermore, the glass according to the invention should satisfy further conditions which are formulaically related to the composition of constituent phases or the composition of simple oxides, which are shown below.

[0092] Since both types of relationships - those for the composition given in constituent phases and those for the composition given in simple oxides - are used side by side, we first provide conversion matrices for the mutual conversion of both composition data.

[0093] Conversion from the composition of constituent phases to the composition of simple oxides and vice versa

[0094] The composition of constituent phases is given in a standardized form for the purpose of conversion, which is:

[0095] Table 3

[0096] The conversion of these compositions into a composition in mol% with respect to the following simple oxides ... Table 4

[0097] ...is carried out using the matrix given here. The composition in mol% of the base glasses is multiplied as a column vector from the right to the matrix:

[0098] Table 5: Matrix

[0099] The result of multiplying the column vector by the matrix is ​​the composition of the glass in mole percent.

[0100] Conversely, a composition in mole percent can be easily converted into a base glass composition using the respective inverse matrix. Of course, only those base glass compositions are considered to be in accordance with the invention that do not result in negative values ​​for the base glasses upon conversion.

[0101] Importance of the constitutive phases and their selection with regard to the task of the invention

[0102] The system of constituent phases described herein allows the calculation of a wide variety of glass properties. These properties cannot be derived from the oxide composition alone; the requirement for specific values ​​of these properties represents a second class of limitations on the composition range defined by Table 2. The combination of Table 2 with Table 1, in turn, is a limitation on Table 1, which specifies the composition in simple oxides.Within the composition space spanned by Table 1, those glass compositions are useful which can be converted into the basic system of the constituent phases without negative phase fractions and which obey both the limits defined in Table 1 for the fractions of the simple oxides and the limits defined in Table 2 or other tables for the fractions of the individual constituent phases (first class of restrictions).

[0103] The second class of restrictions includes that the values ​​calculated from the composition present in constituent phases for the thermal expansion coefficient and / or the fracture toughness and / or the hydrogen permeability satisfy the claimed requirements and / or that advantageous values ​​also result for one or more other calculated parameters.

[0104] The composition is selected with regard to the phases constituting the glass within the limits described herein. The phases constituting the glass are, of course, not crystalline in the glass product, but amorphous. However, this does not mean that the constituent phases in the amorphous state have completely different building blocks than in the crystalline state. As stated above, the topology of the building blocks is comparable, for example, the coordination of the cations involved with surrounding oxygen atoms or the interatomic distance resulting from the coordination and strength of the bond between these cations and surrounding oxygen atoms. Therefore, many properties of the glass of the invention can be well described on the basis of the constituent phases, in particular to illustrate the inventive achievement and the problems overcome by the invention (see Conradt R., loc. cit.).Of course, the glass can be produced not only using the corresponding crystals, but also using the usual glass raw materials, as long as the stoichiometric ratios allow the formation of the corresponding components of the base glasses.

[0105] Phases are selected based on their hydrogen permeability, density, thermal expansion coefficient, and fracture toughness. Hydrogen permeability is assumed to depend primarily on the packing density (the lower the packing density, the greater the hydrogen permeability) and the shear modulus G (according to the theory of Anderson and Stuart, the shear modulus is the decisive parameter for the activation energy during the movement of an uncharged particle in a glass matrix; see OL Anderson, DA Stuart, Calculation of Activation Energy of Ionic Conductivity, Journal of The American Ceramic Society, Vol. 37, No. 12, pages 573-580, 1954). The following provides calculation methods for calculating the density, thermal expansion coefficient, fracture toughness, packing density, and shear modulus of a given composition of constituent phases.These calculation methods are crucial both in the selection of the constituent phases and in the composition of a glass according to the invention from these constituent phases.

[0106] When searching for suitable calculation methods, one surprisingly finds that simple formulas can be found for the properties mentioned, from which key figures or approximate values ​​for these properties can be calculated, which in turn allow a rapid classification of glass compositions as favorable or unfavorable with regard to the object of the invention.

[0107] Density, molar volume and packing density

[0108] Remarkably, the density p can be easily calculated using the lever rule from the molar masses Mi and densities pi of the constituent phases:

[0109] The numerator of (1) is the molar mass, the denominator is the molar volume V moiof the glass. This allows the density of the glass systems addressed here to be predicted with an average accuracy of 1%. The density values ​​listed below in Table 6 can be found in A. Shyam, J. Muth, E. Lara-Curzio, Elastic properties of ß-eucryptite in the glassy and microcracked crystalline states, Acta Materialia Volume 60, Issue 16, September 2012, Pages 5867-5876: Eucryptite, test reports from the accredited testing laboratory of Schott AG, Mainz, Germany: Sodium layer silicate, Cordierite, NH Bansal, RH Doremus, Handbook of Glass Properties, Academic Press, Orlando, San Diego, New York, Austin, London, Montreal, Sydney, Tokyo, Toronto: Nepheline, OV Mazurin, MV Streltsina, TP Shvaiko-Shvaikovskaya, Handbook of Glass Data AC, Elsevier, Amsterdam, 1983-1987: Malinkoite, Kaisilite (density value for Kaisilite by extrapolation), Heraeus Quarzglas GmbH & Co. KG, Quarzstr. 8, 63450 Hanau, Germany, website, accessed on September 12, 2021, Quartz_lamp_materials_EN.pdf (heraeus.com): Quartz glass.

[0110] From the molar volume we calculate the packing density of the glass as an intermediate value for further calculations. To do this we first calculate the (molar) ion volume for each constituent phase. By this we mean the volume occupied by one mole of the constituent phase (more precisely: one mole of the constituent phase normalized to a simple oxide) when viewed as spherical ions with what Robert Shannon called the “effective radius”, see Robert D. Shannon, Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides, Acta Cryst. A32 (1976), pp. 751-767. These radii differ depending on the coordination number. For the cations the necessary coordination numbers have been taken from the mineralogical literature listed below in the discussion of the constituent phases; according to Conradt R., loc. cit., we assume that the coordination numbers of the cations in the glass are equal to those of the corresponding crystal phases. The oxygen atoms are assigned to the cations according to their valence, i.e., half an oxygen ion is allocated to each sodium ion, and so on. The individual oxygen ion is then assumed to be coordinated in a manner consistent with this assignment, i.e., an oxygen ion assigned to a silicon ion is doubly coordinated, and so on. If no explicit radius values ​​are available for individual coordination numbers in the table by Robert D. Shannon, loc. cit., interpolation or extrapolation is used.

[0111] The resulting molar ion volumes are together with the molar masses and density values ​​as well as the The resulting packing density is tabulated below.

[0112] Table 6 Molar masses, densities and molar ion volumes of the standardized constituent phases

[0113] With regard to weight, the density of the glass calculated according to formula (1) should preferably not exceed 2.70 g / cm 3 more preferably a maximum of 2.65 g / cm 3 , even more preferably a maximum of 2.60 g / cm 3 . In view of the packing density increasing with the density ia, the density of the glass calculated according to formula (1) should preferably be, for example, at least 2.20 g / cm 3 , at least 2.25 g / cm 3 , or at least 2.30 g / cm 3 The density of the glass calculated according to formula (1) can, for example, be in a range of 2.20 to 2.70 g / cm 3 , from 2.25 to 2.65 g / cm 3 or from 2.30 to 2.60 g / cm 3 lay.

[0114] The packing density x of the glass calculated according to formula (2) can be, for example, at least 0.49, at least 0.50, at least 0.51, or at least 0.52, in view of the hydrogen permeability which decreases with increasing packing density. In view of the tendency to crystallize which generally increases with increasing packing density, the packing density x of the glass calculated according to formula (2) should preferably be, for example, at most 0.62, at most 0.61, at most 0.60, at most 0.59, at most 0.58, or at most 0.57. The packing density x of the glass calculated according to formula (2) can, for example, be in a range from 0.49 to 0.62, from 0.49 to 0.61, from 0.49 to 0.60, from 0.50 to 0.59, from 0.51 to 0.58, or from 0.52 to 0.57.

[0115] Thermal expansion coefficient

[0116] Remarkably, the coefficient of thermal expansion (GTE) can also be calculated using a simple lever rule. To do this, the thermal expansion coefficients of the constituent phases GTE; are weighted with their volume fractions and bulk moduli and added together, see formula (3) below, which is identical to formula (12) in CP Wong, RS Bollampally, Thermal Conductivity, Elastic Modulus, and Coefficient of Thermal Expansion of Polymer Composites Filled with Ceramic Particles for Electronic Packaging, School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, downloaded from academia.edu on September 12, 2021, (PDF) Thermal Conductivity, Elastic Modulus, and Coefficient of Thermal Expansion of Polymer Composites Filled with Ceramic Particles for Electronic Packaging | ^3 / ® - Academia.edu.The volume fractions of the constituent phases are calculated directly from the molar volumes of the constituent phases and their molar fraction.

[0117] The CTEj can be found in the following table:

[0118] Table 7 Molar masses, densities and molar ion volumes of the standardized constituent phases

[0119] The values ​​are taken from: Test reports from the accredited testing laboratory of Schott AG, Mainz, Germany: Sodium phyllosilicate, cordierite, nepheline, NH Bansal, RH Doremus, Handbook of Glass Properties, Academic Press, Orlando, San Diego, New York, Austin, London, Montreal, Sydney, Tokyo, Toronto: Eucryptite, malinkoite (the latter by extrapolation), Heraeus Quarzglas GmbH & Co. KG, Quarzstr. 8, 63450 Hanau, Germany, website, accessed on September 12, 2021, Quartz_lamp_materials_EN.pdf (heraeus.com): Quartz glass. The value for kaisilite was determined by extrapolating the values ​​for eucryptite and nepheline. It is known from the literature that the thermal expansion coefficient, for example for metals, is inversely proportional to the binding energy (or to the “depth of the interatomic potential wells”), see for example H. Föll, script for the lecture “Introduction to Materials Science I”, Christian Albrechts-University Kiel, pp. 79 - 83.Therefore, the CTE of kaisilite is obtained by plotting the CTEs of eucryptite and nepheline against the average bond strength (or "average potential well depth", see the following discussion on elastic modulus) per cation against the average bond energy per cation and extending the line passing through these points to the average bond energy per cation.

[0120] The compression modulus K and the shear modulus G, which are required below and therefore also given here, are calculated from the elastic modulus E (see the further explanations below for the calculation of the elastic modulus E according to formula (8)), and the Poisson's ratio p (see the further explanations below for the calculation of the Poisson's ratio p according to formula (9)), according to:

[0121] K ~ 3(l E -2n)

[0122] See, for example, H. Föll, script for the lecture “Introduction to Materials Science I”, Christian Albrechts-University Kiel, pp. 79 - 83.

[0123] Since the CTE of carbon fibers is -0.1 ppm / K in the longitudinal direction and 10 ppm / K in the transverse direction, the CTE of the glass according to the invention is preferably 3.5-9.5 ppm / K, particularly preferably 5-8 ppm / K.

[0124] The CTE of the glass calculated according to formula (3) is, for example, at least 3.5 ppm / K, at least 4.0 ppm / K, at least 4.5 ppm / K, or at least 5.0 ppm / K. The CTE of the glass calculated according to formula (3) is, for example, at most 9.5 ppm / K, at most 9.0 ppm / K, at most 8.5 ppm / K, or at most 8.0 ppm / K. The CTE of the glass calculated according to formula (3) can, for example, be in a range from 3.5 to 9.5 ppm / K, from 4.0 to 9.0 ppm / K, from 4.5 to 8.5 ppm / K, or from 5.0 to 8.0 ppm / K.

[0125] Also important is the ratio of the thermal expansion coefficients of the glass compared to the reinforcing material. The difference between the CTE of the reinforcing material and the CTE of the glass calculated according to formula (3) is preferably in a range from 0.0 to 10.0 ppm / K, from 0.1 to 7.5 ppm / K, from 0.2 to 5.0 ppm / K, from 0.5 to 2.5 ppm / K, or from 1.0 to 2.0 ppm / K. The difference between the CTE of the reinforcing material and the CTE of the glass calculated according to formula (3) is preferably at most 10.0 ppm / K, at most 7.5 ppm / K, at most 5.0 ppm / K, at most 2.5 ppm / K, or at most 2.0 ppm / K. The difference between the CTE of the reinforcement material and the CTE of the glass calculated according to formula (3) can be, for example, about 0.0 ppm / K, at least 0.1 ppm / K, at least 0.2 ppm / K, at least 0.5 ppm / K, or at least 1.0 ppm / K.“Difference” is understood to mean, in particular, the difference between the CTE of the reinforcement material and the CTE of the glass calculated according to formula (3), or the amount of this difference. The difference between the GTE of the reinforcement material in the transverse direction and the GTE of the glass calculated according to formula (3) is preferably in a range from 0.0 to 10.0 ppm / K, from 0.1 to 7.5 ppm / K, from 0.2 to 5.0 ppm / K, from 0.5 to 2.5 ppm / K, or from 1.0 to 2.0 ppm / K. The difference between the GTE of the reinforcement material in the transverse direction and the GTE of the glass calculated according to formula (3) is preferably at most 10.0 ppm / K, at most 7.5 ppm / K, at most 5.0 ppm / K, at most 2.5 ppm / K, or at most 2.0 ppm / K. The difference between the GTE of the reinforcing material in the transverse direction and the GTE of the glass calculated according to formula (3) can be, for example, about 0.0 ppm / K, at least 0.1 ppm / K, at least 0.2 ppm / K, at least 0.5 ppm / K, or at least 1.0 ppm / K.The term ‘difference’ means, in particular, the difference between the GTE of the reinforcing material in the transverse direction and the GTE of the glass calculated according to formula (3) or the amount of this difference.

[0126] The difference between the GTE of the glass calculated according to formula (3) and the GTE of the reinforcement material in the longitudinal direction is preferably in a range from 1.0 to 12.5 ppm / K, from 2.5 to 10.0 ppm / K or from 5.0 to 7.5 ppm / K. The difference between the GTE of the glass calculated according to formula (3) and the GTE of the reinforcement material in the longitudinal direction can, for example, be at least 1.0 ppm / K, at least 2.5 ppm / K or at least 5.0 ppm / K. The difference between the GTE of the glass calculated according to formula (3) and the GTE of the reinforcement material in the longitudinal direction can, for example, be at most 12.5 ppm / K, at most 10.0 ppm / K or at most 7.5 ppm / K. The term “difference” is to be understood in particular as the difference between the GTE of the glass calculated according to formula (3) and the GTE of the reinforcement material in the longitudinal direction or the amount of this difference.

[0127] Elastic modulus

[0128] The starting point for calculating the elastic modulus is the theory of Makishima and Mackenzie, see “Direct calculation of Young's modulus of glass”, “Calculation of bulk modulus, shear modulus and Poisson's ratio of glass”, J. Non-Crystall. Sol., 1973 and 1975.

[0129] We first need an expression for the dissociation energy per volume, which we calculate from the average bond strength and the molar volume.

[0130] In a simple illustration of oxide glasses, the cations are placed in a potential well formed by the surrounding oxygen atoms, and the depth is taken to be the sum of the bond strengths of the various single bonds to the surrounding oxygen atoms, thus concentrating the entire interaction energy in potential wells with the cations in the center and the oxygen atoms in the periphery. This eliminates the need to consider the reverse case; it would also be more difficult to analyze, since an oxygen atom can be located between several different cations, which, conversely, cannot occur in purely oxide glasses. These values ​​are tabulated, e.g., in

[0131] DE 10 2014 119 594 A1 :

[0132] Table 8

[0133] From the composition of a glass from the constituent phases listed above, the number of different cations contained in the respective phases and the potential well depths per cation listed above, an average potential well depth or average bond strength per cation can be calculated:

[0134] The number z of cations per mole is:

[0135] Where m is the number of cation types occurring, E po t,j is the potential well depth tabulated above for the j-th cation type and Zj is the number of cations of the j-th type in the i-th constituent phase and Cj (as in all formulas used herein) is the mole fraction of the i-th constituent phase.

[0136] The sums over j are tabulated below: Table 9

[0137] The product of the average potential well depth per cation and the number of cations is then the desired dissociation energy per mole.

[0138] As in Makishima and Mackenzie, a linear relationship between elastic modulus and dissociation energy density is now assumed:

[0139] The evaluation of a series of different silicate glasses of different types, but not those with an excess of boron compared to the alkali and alkaline earth oxides less the aluminum oxide, leads to the following formula:

[0140] E pot in kJ / mol, z dimensionless (moles of cations per mole of glass) and V moi in cm 3 to use. E pot is to be determined according to equation (5) and Table 9, z is to be determined according to equation (6) and Table 9. V moi is the denominator in equation (1). This yields a mean error of 2 GPa in the calculation of E.

[0141] For a hydrogen barrier material, in view of the relationship with fracture toughness described below, it is advantageous to combine low hydrogen permeability with a high Young's modulus to achieve high fracture toughness. The Young's modulus E calculated according to formula (8) can, for example, be at least 60 GPa, at least 65 GPa, at least 70 GPa, at least 75 GPa, at least 80 GPa, at least 85 GPa, or at least 90 GPa. The Young's modulus E calculated according to formula (8) can, for example, be at most 95 GPa, at most 94 GPa, at most 93 GPa, at most 92 GPa, or at most 91 GPa. The elastic modulus E calculated according to formula (8) can, for example, be in a range from 60 to 95 GPa, from 65 to 94 GPa, from 70 to 94 GPa, from 75 to 93 GPa, from 80 to 92 GPa, from 85 to 92 GPa or from 90 to 91 GPa.

[0142] Poisson's ratio

[0143] The investigation of a series of glasses in the range of the invention has shown that the Poisson's ratio p depends on the packing density to the following, empirically found extent:

[0144] H = 0.5818 ■ - 0.0793 (9)

[0145] The calculation of the Poisson's ratio according to formula (9) maps the above-mentioned preferred ranges for the packing density directly into corresponding ranges for the Poisson's ratio.

[0146] Hydrogen permeability

[0147] The investigation of a series of glasses has shown that, as stated above, the hydrogen permeability p depends on the packing density % and the shear modulus G in the following empirically found measure: 14.203 (10)

[0148] The numerical value of the specified base 10 logarithm is preferably < -19,500, particularly preferably < -20,000, < -20,100, < -20,200, < -20,300, or < -20,400, very particularly preferably < -20,500, < -20,600, < -20,700, < -20,800, or < -20,900, even more preferably < -21,000, or < -21,250, even more preferably < -21,500, or < -21,750, even more preferably < -22,000, or < -22,250, even more preferably < -22,500, or < -22,750, even more preferably < -23,000, or < -23,250, even more preferably < -23,500, or < -23,750, most preferably < -24,000. The base 10 logarithm of the hydrogen permeability p calculated according to formula (10) can, for example, be more than -29,000, more than -28,500, more than -28,000, more than -27,500, more than -27,000, more than -26,500, more than -26,000, more than -25,500, more than -25,000, or more than -24,500. The base 10 logarithm of the hydrogen permeability p calculated according to formula (10) can, for example, be in a range from more than -29,000 to less than -20,000, from more than -29,000 to less than -20,100, from more than -29,000 to less than -20,200, from more than -29,000 to less than -20,300, from more than -29,000 to less than -20,400, from more than -29,000 to less than -20,500, from more than -29,000 to less than -20,600, from more than -29,000 to less than -20,700, from more than -29,000 to less than -20,800, from more than -29,000 to less than -20,900, from more than -29,000 to less than -21,000, from more than -29,000 to less than -21,250, from more than -29,000 to less than -21,500, from more than -29,000 to less than -21,750, from more than -28,500 to less than -22,000, from more than -28,000 to less than -22,250, from more than -27,500 to less than -22,500, from more than -27,000 to less than -22,750, from more than -26,500 to less than -23,000, from more than -26,000 to less than -23,250, from more than -25,500 to less than -23,500, from more than -25,000 to less than -23,750, or from more than -24,500 to less than -24,000.

[0149] In formula (10), G represents the shear modulus calculated according to formula (4a), and % represents the packing density calculated according to formula (2). In formula (10), the hydrogen permeability p specifically represents the hydrogen permeability at a temperature of 473 K.

[0150] Fracture toughness Ki c

[0151] Under the Ki c is understood as the value measured by the SEPB method, for which NIST has found a relationship with the Young's modulus, see George D. Quinn, Jeffrey J. Swab, Fracture toughness of glasses as measured by the SCF and SEPB methods, Journal of the European Ceramic Society 37 (2017) 4243-4257.

[0152] The comparison of Ki measured in the accredited test laboratory of Schott AG, Mainz, Germany according to the SEPB method on a range of aluminosilicates, borosilicates, quartz glass, and binary silicates c -values ​​with the values ​​for the elastic moduli calculated according to (4, 8, 9) (calculated) leads to the formula:

[0153] K lc = 0.0147 ■ E berechnet - 0.3503 (11)

[0154] The Ki calculated according to formula (11) c is preferably at least 0.80 MPa > / m, particularly preferably at least 0.85 MPa > / m, very particularly preferably at least 0.90 MPa > / m, even more preferably at least 0.95 MPa > / m, most preferably at least 1.00 MPa > / m. The Ki calculated according to formula (11) c can be, for example, not more than 1.05 MPa > / m, not more than 1.04 MPa > / m, not more than 1.03 MPa > / m, not more than 1.02 MPa > / m or not more than 1.01 MPa > / m. The Ki calculated according to formula (11) ccan, for example, be in a range from 0.80 to 1.05 MPa > / m, from 0.85 to 1.04 MPa > / m, from 0.90 to 1.03 MPa > / m, from 0.95 to 1.02 MPa > / m or from 1.00 to 1.01 MPa > / m. Selection of suitable constituent phases

[0155] Silicon dioxide

[0156] The crystal lattice of crystalline SiO2 consists of three-dimensionally interconnected SiO4 tetrahedra. Silica glass, i.e., pure SiO2, also has a three-dimensional network structure, with a mesh size whose radius is approximately 0.6 Å; see OL Anderson, DA Stuart, "Calculation of Activation Energy of Ionic Conductivity," Journal of the American Ceramic Society, Vol. 37, No.

[0157] 12, pages 573-580, 1954. (The mesh diameter is therefore approximately 1.2 Å.) The H2 molecule has a radius of approximately 1.2 Å, see OL Anderson, DA Stuart, loc. cit. Thus, silica glass is, in principle, suitable as a hydrogen barrier material.

[0158] The key values ​​defined above are for SiÜ2:

[0159] The hydrogen permeability is significantly higher than that of the following constituent phases, which, however, all have high thermal expansion coefficients. Therefore, SiO2 is added to the glass according to the invention primarily to adjust the thermal expansion coefficient to the desired value.

[0160] Calculated elastic modulus and fracture toughness are in the medium range.

[0161] The proportion of the constituent phase silicon dioxide can, for example, be in a range from 0.0 to 50 mol%, from 1.0 to 45 mol%, from 2.0 to 40 mol%, from 4.0 to 35 mol%, from 6.0 to 30 mol%, from 8.0 to 25 mol%, or from 10 to 20 mol%. The proportion of the constituent phase silicon dioxide can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 4.0 mol%, at least 6.0 mol%, at least 8.0 mol%, at least 10 mol%, at least 15 mol%, or at least 20 mol%. The proportion of the constituent phase silicon dioxide can, for example, be at most 50 mol%, at most 45 mol%, at most 40 mol%, at most 35 mol%, at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 10 mol%, at most 5.0 mol%, at most 2.0 mol%, or at most 1.0 mol%. The glass can also be free of the constituent phase silicon dioxide.

[0162] Sodium phyllosilicate

[0163] Due to its higher packing density, the sodium layered silicate (3Na2O-8SiC>2) / 11 has a lower hydrogen permeability than SiC>2.

[0164] The key values ​​defined above are for (3Na2O8Si02) / 11 :

[0165] The thermal expansion coefficient is high, so that this constituent phase is only suitable as an additive.

[0166] Calculated elastic modulus and fracture toughness are in the lower range.

[0167] The proportion of sodium layered silicate can, for example, be in a range from 0.0 to 50 mol%, from 1.0 to 45 mol%, from 2.0 to 40 mol%, from 5.0 to 35 mol%, from 10 to 30 mol%, from 20 to 25 mol%. The proportion of sodium layered silicate can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 10 mol%, at least 15 mol%, at least 20 mol%, at least 25 mol%, or at least 30 mol%. The proportion of sodium phyllosilicate can, for example, be at most 50 mol%, at most 45 mol%, at most 40 mol%, at most 35 mol%, at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 10 mol%, at most 8.0 mol%, at most 6.0 mol%, at most 5.0 mol%, at most 4.0 mol%, at most 2.0 mol%, or at most 1.0 mol%. The glass can also be free of sodium phyllosilicate.

[0168] Nepheline

[0169] To achieve an even higher hydrogen barrier function than with SiO2, one can switch to so-called "stuffed structures." These are crystals or glasses whose basic framework, like SiO2, is a three-dimensionally cross-linked tetrahedral network, but in which alkali or alkaline earth ions are partially embedded in the meshes. These ions, firstly, further hinder hydrogen transport and, secondly, represent a type of dispersion stiffener, thus increasing the elastic modulus. A suitable system is nepheline, which consists of three-dimensionally cross-linked SiCu and AlC>4 tetrahedra, with sodium ions incorporated into the meshes. According to the invention, one mole of nepheline is defined as one mole of (Na2OAl2O3SiO2) / 4.

[0170] The key values ​​defined above for nepheline are:

[0171] In view of the above-mentioned values, nepheline is suitable as a “base phase” for a hydrogen barrier glass, to which, however, SiC>2, for example, must be added in view of the thermal expansion.

[0172] Calculated elastic modulus and fracture toughness are in the medium range.

[0173] The proportion of nepheline can, for example, range from 0.0 to 100 mol%, from 1.0 to 90 mol%, from 2.0 to 80 mol%, from 5.0 to 70 mol%, from 10 to 60 mol%, from 20 to 50 mol%, or from 30 to 40 mol%. The proportion of nepheline can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 10 mol%, at least 15 mol%, at least 20 mol%, at least 25 mol%, or at least 30 mol%. The nepheline content can, for example, be at most 90 mol%, at most 80 mol%, at most 70 mol%, at most 60 mol%, at most 50 mol%, at most 40 mol%, at most 35 mol%, at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 10 mol%, at most 5.0 mol%, at most 2.0 mol%, or at most 1.0 mol%. The glass can also be free of nepheline. Eucryptite

[0174] Compared to nepheline, eucryptite exhibits a significantly increased Young's modulus, which in turn results in lower hydrogen permeability. For the purposes of the present invention, one mole of eucryptite is defined as one mole of (Li2OAl2O3'2SiO2) / 4.

[0175] The key values ​​defined above for eucryptite are:

[0176] Given these values, eucryptite is even more suitable as a base phase for a hydrogen barrier material than nepheline. Due to its lower coefficient of expansion, the addition of SiO2 can be lower to achieve an expansion coefficient comparable to the average coefficient of carbon fiber. This, in turn, is beneficial for the hydrogen barrier effect. Calculated elastic modulus and fracture toughness are in the upper range. The disadvantage is the price of the lithium oxide component.

[0177] The proportion of eucryptite can, for example, range from 0.0 to 100 mol%, from 1.0 to 90 mol%, from 2.0 to 80 mol%, from 5.0 to 70 mol%, from 10 to 60 mol%, from 20 to 50 mol%, or from 30 to 40 mol%. The proportion of eucryptite can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 10 mol%, at least 15 mol%, at least 20 mol%, at least 25 mol%, at least 30 mol%, at least 40 mol%, at least 50 mol%, or at least 60 mol%. The eucryptite content can, for example, be at most 90 mol%, at most 80 mol%, at most 70 mol%, at most 60 mol%, at most 50 mol%, at most 40 mol%, at most 35 mol%, at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 10 mol%, at most 5.0 mol%, at most 2.0 mol%, or at most 1.0 mol%. The glass can also be free of eucryptite.

[0178] Cordierite

[0179] According to the invention, one mole of cordierite is defined as one mole of (2MgO 2Al2O3-5SiO2) / 9. The key values ​​defined above for cordierite are:

[0180] Due to its low expansion coefficient and low hydrogen permeability, cordierite is an excellent base phase for a hydrogen barrier material. To achieve the desired expansion coefficient, constituent phases such as nepheline or eucryptite, which themselves are very good barrier materials, must be added.

[0181] Calculated elastic modulus and fracture toughness are in the upper range.

[0182] The proportion of cordierite can, for example, be in a range from 0.0 to 100 mol%, from 1.0 to 90 mol%, from 2.0 to 80 mol%, from 5.0 to 70 mol%, from 10 to 60 mol%, from 20 to 50 mol%, or from 30 to 40 mol%. The proportion of cordierite can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 10 mol%, at least 15 mol%, at least 20 mol%, at least 25 mol%, at least 30 mol%, at least 40 mol%, at least 50 mol%, or at least 60 mol%. The cordierite content can, for example, be at most 90 mol%, at most 80 mol%, at most 75 mol%, at most 70 mol%, at most 60 mol%, at most 50 mol%, at most 40 mol%, at most 35 mol%, at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 10 mol%, at most 5.0 mol%, at most 2.0 mol%, or at most 1.0 mol%. The glass can also be free of cordierite.

[0183] Malinkoite

[0184] According to the invention, one mole of malinkoite is understood to be one mole (Na2O B2O3'2SiO2) / 4.

[0185] The key values ​​defined above for Malinkoite are:

[0186]

[0187] Given its very low hydrogen permeability, malinkoite is a very good additive component for a hydrogen barrier material. However, to achieve the desired coefficient of thermal expansion, a base glass such as cordierite must be used.

[0188] Compared to malinkoite's aluminum analogue, nepheline, malinkoite exhibits very low hydrogen permeability. Analogous systems with tetrahedrally coordinated boron and aluminum, respectively, are characterized by stiffer bond angles, shorter bond distances, and lower compressibility in the boron-containing analogue than in the aluminum-containing analogue. All of these differences inhibit hydrogen diffusion. From this perspective, malinkoite is therefore a particularly preferred constituent phase.

[0189] Calculated elastic modulus and fracture toughness are in the upper range.

[0190] The proportion of malinkoite can, for example, range from 0.0 to 100 mol%, from 1.0 to 90 mol%, from 2.0 to 80 mol%, from 5.0 to 70 mol%, from 10 to 60 mol%, from 20 to 50 mol%, or from 30 to 40 mol%. The proportion of malinkoite can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 10 mol%, at least 15 mol%, at least 20 mol%, at least 25 mol%, at least 30 mol%, at least 40 mol%, at least 50 mol%, or at least 60 mol%. The malinkoite content can, for example, be at most 90 mol%, at most 80 mol%, at most 75 mol%, at most 70 mol%, at most 60 mol%, at most 50 mol%, at most 40 mol%, at most 35 mol%, at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 10 mol%, at most 5.0 mol%, at most 2.0 mol%, or at most 1.0 mol%. The glass can also be free of malinkoite.

[0191] Cordierite and Malinkoite

[0192] Also of particular importance are the sum of the molar fractions of cordierite and malinkoite, as well as the ratio of the molar fraction of cordierite to the molar fraction of malinkoite. Cordierite and malinkoite are the constituent phases that combine a high elastic modulus and thus high fracture toughness with very low hydrogen permeability. Therefore, their sum preferably accounts for a large proportion.

[0193] The sum of the molar proportions of cordierite and malinkoite is preferably in a range from 50 to 100 mol%, for example from 60 to 90 mol% or from 70 to 80 mol%. The sum of the molar proportions of cordierite and malinkoite is preferably at least 50 mol%, for example at least 60 mol% or at least 70 mol%. The sum of the molar proportions of cordierite and malinkoite can, for example, be at most 90 mol% or at most 80 mol%.

[0194] The molar fraction of cordierite is preferably at least as large as the molar fraction of malinkoite. Preferably, the molar fraction of cordierite is greater than the molar fraction of malinkoite. The difference between the molar fraction of cordierite and the molar fraction of malinkoite is preferably in a range from 0 to 40 mol%, for example from 10 to 30 mol%. The molar fraction of cordierite can exceed the molar fraction of malinkoite, for example, by at least 10 mol% or by at least 20 mol%. The ratio of the molar fraction of cordierite to the molar fraction of malinkoite is preferably in a range from 0.5 to 5.0, preferably from 1.0 to 4.0, from 1.3 to 3.0, from 1.5 to 2.5 or from 1.6 to 2.0. The ratio of the molar proportion of cordierite to the molar proportion of malinkoite is preferably at least 0.5, more preferably at least 1.0, for example at least 1.3, at least 1.5 or at least 1.6.The ratio of the molar fraction of cordierite to the molar fraction of malinkoite is preferably at most 5.0, more preferably at most 4.0, for example at most 3.0, at most 2.5, or at most 2.0. Since cordierite has a thermal expansion coefficient of 3.56 ppm / K and malinkoite has a thermal expansion coefficient of 10.7 ppm / K, the stated ratios of the molar fractions are particularly preferred for adapting the thermal expansion coefficient of the barrier material to the thermal expansion coefficient of the reinforcement material, in particular to the average thermal expansion coefficient of carbon fibers.

[0195] Kaisilite

[0196] According to the invention, one mole of kaisilite is understood to be one mole of (^O AhCh^SiChj.

[0197] The key values ​​defined above for Kaisilit are:

[0198]

[0199] Due to its low hydrogen permeability, Kaisilit is a good base glass admixture for a hydrogen barrier material. Its simultaneously low elastic modulus distinguishes Kaisilit from all other constituent phases with very low hydrogen permeability, which is advantageous for the resilience of a subsequent component. Regarding thermal expansion, SiO2, for example, can also be added. Like all aluminosilicates, it is also a low-brittleness glass. Calculated elastic modulus and fracture toughness are in the lower range.

[0200] The proportion of kaisilite can, for example, be in a range from 0.0 to 40 mol%, from 1.0 to 35 mol%, from 2.0 to 30 mol%, from 5.0 to 25 mol%, or from 10 to 20 mol%. The proportion of kaisilite can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 10 mol%, at least 15 mol%, or at least 20 mol%. The proportion of kaisilite can, for example, be at most 40 mol%, at most 35 mol%, at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 10 mol%, at most 5.0 mol%, at most 2.0 mol%, or at most 1.0 mol%. The glass can also be free of kaisilite.

[0201] Additional components

[0202] In addition to the components already mentioned, the glass may contain further constituents, which are referred to herein as "residue". The proportion of the residue in the glass according to the invention is preferably at most 3.0 mol% in order not to impair the glass properties adjusted by careful selection of suitable base glasses. In particular, the content of individual oxides is preferably limited to <0.5 mol%. In particularly preferred embodiments, the proportion of residue in the glass is at most 2.0 mol%, more preferably at most 1.0 mol% or at most 0.5 mol%. The residue contains, in particular, oxides that are not contained in the base glasses mentioned herein. Thus, the residue contains, in particular, no SiO2, Al2O3, B2O3, Na2O, U2O, K2O, or MgO. In some embodiments, the glass is free of a residue. This means that the glass contains essentially only those oxides that can be assigned to the constituent phases of the phase system described herein.

[0203] When this description states that the glasses are free of a component or constituent phase, or that they do not contain a certain component or constituent phase, this means that this component or constituent phase may only be present in the glasses as an impurity. This means that it is not added in significant quantities.According to the invention, non-essential amounts are amounts of less than 5000 ppm (molar, with respect to the oxides), preferably less than 4000 ppm (molar, with respect to the oxides, more preferably less than 3000 ppm (molar, with respect to the oxides), more preferably less than 2000 ppm (molar, with respect to the oxides), more preferably less than 1000 ppm (molar, with respect to the oxides), preferably less than 500 ppm (molar, with respect to the oxides), preferably less than 300 ppm (molar, with respect to the oxides), particularly preferably less than 100 ppm (molar, with respect to the oxides, very particularly preferably less than 50 ppm (molar, with respect to the oxides) and most preferably less than 10 ppm (molar, with respect to the oxides). The glasses of this invention are in particular free from uranium, lead, arsenic, antimony, bismuth and / or cadmium.

[0204] The remainder does not appear in the formulas. All calculations are performed as if the proportion consisting of the constituent phases were 100%.

[0205] Differences between trigonal boron and four-coordinate boron

[0206] All glasses according to the invention can be represented as a combination of the constituent phases listed in Table 2, taking into account the proportion limits specified in said table. Glasses that do not allow this are not according to the invention. This includes, in particular, all glasses that, like the glasses according to the invention, have corresponding proportions of the oxides SiO2, B2O3, Al2O3, U2O, Na2O, K2O, and / or MgO, but have an excess of boron.

[0207] The glasses according to the invention do not contain excess boron. In particular, the following applies to the glasses according to the invention:

[0208] (ZR2O + ZRO) > (AI2O3 + B2O3) (12a)

[0209] According to the invention, ZR2O + ZRO is understood to mean the sum of the proportions of the alkali metal oxides and the alkaline earth metal oxides, in particular the sum of the proportions of U2O, Na2O, K2O, MgO, CaO, SrO, and BaO. The glasses according to the invention preferably have only small proportions of CaO, SrO, and BaO or are even free of CaO, SrO, and / or BaO. These oxides are not attributable to any of the constituent phases according to the invention and are therefore to be assigned to the residue described above, the proportion of which is preferably small. In preferred embodiments, (12a) can therefore be simplified as follows:

[0210] (Li2O + Na2O + K2O + MgO) > (AI2O3+ B2O3) (12b)

[0211] In inequalities (12a, b), the chemical formulas of the individual simple oxides represent their molar fraction in the respective glass. Glasses in which inequality (12a) and / or inequality (12b) applies are characterized by the fact that the oxygen provided by the alkali and alkaline earth oxides is primarily transferred to the existing aluminum atoms to enable them to achieve the aforementioned fourfold coordination, see, for example, S. Bruns, T. Uesbeck, D. Weil, D. Möncke, L. van Wüllen, K. Durst, D. de Ligny, Influence of AI2O3 Addition on Structure and Mechanical Properties of Borosilicate Glasses, Front. Mater. 7:189 (2020). The remaining oxygen provided by the alkali and alkaline earth oxides is used to enable boron atoms to achieve fourfold coordination. Given the excess of alkali and alkaline earth oxides, no excess boron remains, which, due to the lack of additional oxygen, could only enter trigonal coordination.The glasses of the invention thus preferably contain four-coordinate boron, but are in particular free of trigonal boron.

[0212] Trigonal boron is disadvantageous for a barrier material. Trigonal boron tends to aggregate into larger planar structures, the boroxol rings. Diffusion paths arise parallel to these boroxol rings, increasing hydrogen permeability. This is also reflected in measurements. Welter et al. compared literature values ​​for borosilicates, aluminosilicates, and binary silicates in T. Welter, R. Müller, J. Deubener, U. Marzok, and S. Reinsch, "Hydrogen Permeation Through Glass," Front. Mater. 6:342 (2020). The borosilicates are the borosilicate described by Ried et al. in P. Ried, M. Gaber, R. Müller, J. Deubener, Hydrogen permeability of a barium-aluminoborosilicate glass - A methodical approach, Journal of Non-Crystalline Solids 394-395 (2014), 43-49, and the barium borosilicate glass designated "BABS" and the borosilicate glass designated "BS3" investigated by the same authors in the same publication as well as the method described by Shelby in James E.Shelby, Handbook of Diffusion in Solids and Melts, ASM International, Chicago, IL (1996) considered systems Corning Codes 3320, 7040, 7052, 7720, 7740, and 7900. For all of these glasses, the sum of the mole fractions of B2O3 and Al2O3 is greater than the sum of the mole fractions of the alkali metal oxides R2O and the alkaline earth metal oxides RO. Thus, none of the glasses satisfies inequality (12a).

[0213] They are therefore not in accordance with the invention and are also notable for their relatively high hydrogen permeabilities. The hydrogen permeabilities of the borosilicate glasses considered by Ried and Shelby, as reported in Welter et al., are higher than those of the aluminosilicates and binary silicates also considered by Welter et al. From the compositional analysis in light of the inequalities (12a, b), it can be concluded that the hydrogen permeability-reducing effect of the stuffed structures present in the examples by Ried and Shelby is more than compensated for by the hydrogen permeability-increasing effect of the highly present trigonally coordinated boron.

[0214] Preferred glass compositions

[0215] The preferred embodiments result within the framework of the above-mentioned basic system from the specification of a desired thermal expansion, density and packing density or a desired range for the mentioned sizes.

[0216] The glass is preferably characterized by the following oxide composition:

[0217] The SiO2 content can be, for example, at least 50 mol%, at least 51 mol%, at least 52 mol%, at least 55 mol%, or at least 57 mol%. The SiO2 content can be, for example, at most 75 mol%, at most 70 mol%, at most 68 mol%, at most 65 mol%, at most 64 mol%, or at most 63 mol%. The SiO2 content can, for example, range from 50 to 75 mol%, from 50 to 70 mol%, from 51 to 68 mol%, from 52 to 65 mol%, from 55 to 64 mol%, or from 57 to 63 mol%.

[0218] The proportion of B2O3 can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 3.0 mol%, at least 4.0 mol%, or at least 5.0 mol%. The proportion of B2O3 can, for example, be at most 25 mol%, at most 20 mol%, at most 18 mol%, at most 15 mol%, at most 13 mol%, or at most 11 mol%. The proportion of B2O3 can, for example, be in a range from 0.0 to 25 mol%, from 0.0 to 20 mol%, from 1.0 to 18 mol%, from 2.0 to 15 mol%, from 4.0 to 13 mol%, or from 5.0 to 11 mol%.

[0219] The proportion of AI2O3 can be, for example, at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 10 mol%, at least 11 mol%, at least 12 mol%, at least 13 mol%, or at least 14 mol%. The proportion of AI2O3 can be, for example, at most 25 mol%, at most 24 mol%, at most 23 mol%, at most 22 mol%, at most 21 mol%, at most 20 mol%, at most 19 mol%, at most 18 mol%, or at most 17 mol%. The proportion of AI2O3 can, for example, be in a range from 0.0 to 25 mol%, from 1.0 to 24 mol%, from 2.0 to 23 mol%, from 5.0 to 22 mol%, from 10 to 21 mol%, from 11 to 20 mol%, from 12 to 19 mol%, from 13 to 18 mol%, or from 14 to 17 mol%.

[0220] The sum of the proportions of B2O3 and Al2O3 can, for example, be at least 5.0 mol%, at least 8.0 mol%, at least 10 mol%, at least 15 mol%, or at least 17 mol%. The sum of the proportions of B2O3 and Al2O3 can, for example, be at most 30 mol%, at most 28 mol%, at most 26 mol%, at most 25 mol%, or at most 24 mol%. The sum of the proportions of B2O3 and Al2O3 can, for example, range from 5.0 to 30 mol%, from 8.0 to 28 mol%, from 10 to 26 mol%, from 15 to 25 mol%, or from 17 to 24 mol%.

[0221] The proportion of MgO can be, for example, at least 1.0 mol%, at least 2.0 mol%, at least 3.0 mol%, at least 4.0 mol%, at least 5.0 mol%, at least 6.0 mol%, at least 7.0 mol%, or at least 8.0 mol%. The proportion of MgO can be, for example, at most 30 mol%, at most 25 mol%, at most 23 mol%, at most 20 mol%, at most 18 mol%, at most 15 mol%, at most 14 mol%, at most 12 mol%, or at most 10 mol%. The MgO content can, for example, range from 0.0 to 30 mol%, from 1.0 to 25 mol%, from 2.0 to 23 mol%, from 3.0 to 20 mol%, from 4.0 to 18 mol%, from 5.0 to 15 mol%, from 6.0 to 14 mol%, from 7.0 to 12 mol%, or from 8.0 to 10 mol%. MgO has proven particularly advantageous for achieving low hydrogen permeability.

[0222] The proportion of U2O can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 10 mol%, at least 15 mol% or at least 20 mol%. The proportion of U2O can, for example, be at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 10 mol%, or at most 5.0 mol%. The proportion of U2O can, for example, be in a range from 0.0 to 25 mol%, from 0.0 to 20 mol%, from 0.0 to 15 mol%, from 1.0 to 10 mol%, or from 2.0 to 5.0 mol%.

[0223] The proportion of Na2O can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 4.0 mol%, at least 5.0 mol%, or at least 7.0 mol%. The proportion of Na2O can, for example, be at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 15 mol%, at most 14 mol%, at most 13 mol%, at most 12 mol%, or at most 11 mol%. The proportion of Na2O can, for example, be in a range from 0.0 to 30 mol%, from 0.0 to 25 mol%, from 0.0 to 20 mol%, from 0.0 to 15 mol%, from 1.0 to 14 mol%, from 2.0 to 13 mol%, from 4.0 to 12 mol%, or from 5.0 to 11 mol%.

[0224] The proportion of K2O can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 3.0 mol%, at least 4.0 mol%, or at least 5.0 mol%. The proportion of K2O can, for example, be at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 12 mol%, at most 10 mol%, at most 8.0 mol%, or at most 6.0 mol%. The proportion of K2O can, for example, be in a range from 0.0 to 25 mol%, from 0.0 to 20 mol%, from 0.0 to 15 mol%, from 0.0 to 12 mol%, from 0.0 to 10 mol%, from 0.0 to 8.0 mol%, or from 0.0 to 6.0 mol%.

[0225] According to the invention, ZR2O is understood to mean the sum of the proportions of the alkali metal oxides, in particular the sum of the proportions of U2O, Na2O and K2O. ZR2O can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 4.0 mol%, at least 5.0 mol%, or at least 6.0 mol%. ZR2O can, for example, be at most 30 mol%, at most 25 mol%, at most 22 mol%, at most 20 mol%, at most 18 mol%, or at most 17 mol%. ZR2O can, for example, be in a range from 0.0 to 30 mol%, from 0.0 to 25 mol%, from 1.0 to 22 mol%, from 2.0 to 20 mol%, from 4.0 to 18 mol%, or from 5.0 to 17 mol%.

[0226] According to the invention, ZRO is understood to mean the sum of the proportions of the alkaline earth metal oxides, in particular the sum of the proportions of MgO, CaO, SrO and BaO. ZRO can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, at least 6.0 mol%, or at least 8.0 mol%. ZRO can, for example, be at most 25 mol%, at most 20 mol%, at most 18 mol%, at most 15 mol%, or at most 14 mol%. ZRO can, for example, be in a range from 0.0 to 25 mol%, from 2.0 to 20 mol%, from 5.0 to 18 mol%, from 6.0 to 15 mol%, or from 8.0 to 14 mol%.

[0227] According to the invention, ZR2O+ZRO is understood to mean the sum of the proportions of alkali metal oxides and alkaline earth metal oxides, in particular the sum of the proportions of U2O, Na2O, K2O, MgO, CaO, SrO, and BaO. ZR2O+ZRO can, for example, be at least 5.0 mol%, at least 8.0 mol%, at least 10 mol%, at least 12 mol%, at least 15 mol%, or at least 17 mol%. ZR2O+ZRO can, for example, be at most 30 mol%, at most 28 mol%, at most 27 mol%, at most 26 mol%, at most 25 mol%, or at most 24 mol%. For example, ZR2O+ZRO can be in a range from 5.0 to 30 mol%, from 8.0 to 28 mol%, from 10 to 27 mol%, from 12 to 26 mol%, from 15 to 25 mol%, or from 17 to 24 mol%.

[0228] Of particular importance can be the ratio of the molar fractions of the sums ZR2O+ZRO and B2O3+AI2O3, i.e., the ratio (ZR2O+ZRO) / (B2O3+AI2O3). It is advantageous if the molar fractions of the sum ZR2O+ZRO and the molar fractions of the sum B2O3+AI2O3 are similar or even equal, so that the ratio (ZR2O+ZRO) / (B2O3+AhO3) is close to or equal to 1:1. If the ratio is too large, there are too many non-bridging oxygen atoms (NBO), which has a negative impact on chemical resistance. It is preferred that the ratio (ZR2O+ZRO) / (B2O3+AhO3) is at least 1.00:1.00. If the proportion is too small, there is too much trigonal boron (which negatively affects the desired barrier effect against hydrogen) or, in the absence of boron, the system tends to devitrify.The proportion ratio (ZR2O+ZRO) / (B2O3+AhO3) can, for example, be in a range from 1.00:1 to 1.25:1, from 1.00:1 to 1.20:1, from 1.00:1 to 1.15:1, from 1.00:1 to 1.10:1, from 1.00:1 to 1.05:1, from 1.00:1 to 1.02:1, or from 1.00:1 to 1.01:1, or be 1:1, for example about 1.00:1.00. The proportion ratio (ZR2O+ZRO) / (B2O3+AhO3) is at least about 1.00:1.00. The proportion ratio (ZR2O+ZRO) / (B2O3+AhO3) can, for example, be at most 1.25:1, at most 1.20:1, at most 1.15:1, at most 1.10:1, at most 1.05:1, at most 1.02:1, at most 1.01:1, or at most 1:1, for example at most about 1.00:1.00.

[0229] The difference in the molar fractions of the sums ZR2O+ZRO and B2O3+AI2O3, i.e. (ZR2O+ZRO)-(B2O3+AI2O3), can be of particular importance. It is advantageous if the molar fractions of the sum ZR2O+ZRO and the molar fractions of the sum B2O3+AI2O3 are similar or even equal, so that the difference (ZR2O+ZRO)-(B2O3+AI2O3) is close to or equal to 0. If the alkali metals and alkaline earth metals are present in large excess, there are too many non-bridging oxygen atoms (NBO). If B2O3 and AI2O3 are present in excess, there is too much trigonal boron. Trigonal boron has a negative effect on the desired barrier effect against hydrogen. An excess of B2O3+AI2O3, in particular, should therefore be avoided. Preferably, the difference (ZR2O+ZROHB2O3+AI2O3) is > 0 mol%. The sum of the U2O and MgO contents can also be of particular importance.The sum of the proportions of U2O and MgO can, for example, range from 1.0 to 30 mol%, from 2.0 to 25 mol%, from 5.0 to 20 mol%, or from 10 to 15 mol%. The sum of the proportions of U2O and MgO can, for example, be at least 1.0 mol%, at least 2.0 mol%, at least 5.0 mol%, or at least 10 mol%, in some embodiments even at least 15 mol% or at least 20 mol%. The sum of the proportions of Li2O and MgO can, for example, be at most 30 mol%, at most 25 mol%, or at most 20 mol%, in some embodiments even at most 15 mol% or at most 10 mol%.

[0230] The proportion of MgO is preferably greater than the proportion of Li2O. With MgO, a particularly low hydrogen permeability can be achieved. The proportion of MgO is preferably at least 1.0 mol%, more preferably at least 2.0 mol%, more preferably at least 3.0 mol%, more preferably at least 4.0 mol%, more preferably at least 5.0 mol%, more preferably at least 6.0 mol% greater than the proportion of U2O. The proportion of MgO can, for example, be at most 30 mol%, at most 25 mol%, at most 20 mol%, at most 15 mol%, at most 12 mol%, or at most 10 mol% greater than the proportion of U2O. The difference in the proportions of MgO and U2O can, for example, be in a range from 1.0 to 30 mol%, from 2.0 to 25 mol%, from 3.0 to 20 mol%, from 4.0 to 15 mol%, from 5.0 to 12 mol% or from 6.0 to 10 mol%.

[0231] A preferred composition is characterized by the following composition ranges: A further preferred composition is characterized by the following composition ranges:

[0232] A further preferred composition is characterized by the following phases constituting the glass: A further preferred composition is characterized by the following composition ranges: A further preferred composition is characterized by the following composition ranges:

[0233] A further preferred composition is characterized by the following composition ranges:

[0234] A further preferred composition is characterized by the following composition ranges:

[0235] The composition of the glasses of the invention is preferably characterized by the following glass-constituting phases:

[0236] More preferably, the composition of the glasses of the invention is characterized by the following glass-constituting phases:

[0237]

[0238] More preferably, the composition of the glasses of the invention is characterized by the following glass-constituting phases:

[0239] More preferably, the composition of the glasses of the invention is characterized by the following glass-constituting phases:

[0240] More preferably, the composition of the glasses of the invention is characterized by the following glass-constituting phases:

[0241]

[0242] More preferably, the composition of the glasses of the invention is characterized by the following glass-constituting phases:

[0243] More preferably, the composition of the glasses of the invention is characterized by the following glass-constituting phases:

[0244]

[0245] More preferably, the composition of the glasses of the invention is characterized by the following glass-constituting phases:

[0246] More preferably, the composition of the glasses of the invention is characterized by the following glass-constituting phases:

[0247] The invention preferably relates to a glass comprising the following components in the stated proportions (in mol%): where the sum of the molar fractions of the alkali metal oxides R2O and the alkaline earth metal oxides RO is equal to or greater than the sum of the molar fractions of B2O3 and AI2O3, where the composition of the glass is additionally characterized by the following phases constituting the glass: and where the base 10 logarithm of the hydrogen permeability p calculated according to formula (10) is less than -20,000.

[0248] The invention particularly preferably relates to a glass comprising the following components in the stated proportions (in mol%): where the sum of the molar fractions of the alkali metal oxides R2O and the alkaline earth metal oxides RO is equal to or greater than the sum of the molar fractions of B2O3 and AI2O3, where the composition of the glass is additionally characterized by the following phases constituting the glass: and where the base 10 logarithm of the hydrogen permeability p calculated according to formula (10) is less than -20,500.

[0249] The invention further preferably relates to a glass comprising the following components in the stated proportions (in mol%): where the sum of the molar fractions of the alkali metal oxides R2O and the alkaline earth metal oxides RO is equal to or greater than the sum of the molar fractions of B2O3 and AI2O3, where the composition of the glass is additionally characterized by the following phases constituting the glass: and wherein the base 10 logarithm of the hydrogen permeability p calculated according to formula (10) is less than -21,000.

[0250] Even more preferably, the invention relates to a glass comprising the following components in the stated proportions (in mol%): where the sum of the molar fractions of the alkali metal oxides R2O and the alkaline earth metal oxides RO is equal to or greater than the sum of the molar fractions of B2O3 and AI2O3, where the composition of the glass is additionally characterized by the following phases constituting the glass: and wherein the base 10 logarithm of the hydrogen permeability p calculated according to formula (10) is less than -21,500.

[0251] Production

[0252] The invention also relates to a method for producing a hydrogen storage device, in particular a hydrogen storage device of the present invention. The method preferably comprises the following steps: • Forming a combination material, in particular a material composite or a composite material, into a wall, wherein the wall has one or more openings,

[0253] • Insert a valve into each of the openings.

[0254] The invention also relates to a method for producing a combination material, for example a composite material or a composite material, in particular a combination material, for example a composite material or a composite material of the present invention. The method preferably comprises the following steps:

[0255] • Providing a barrier material,

[0256] • Providing a reinforcing material,

[0257] • Combining the barrier material and the reinforcement material to form a combination material, in particular a material composite or a composite material.

[0258] In the case of the composite material, the joining can be carried out, for example, by hot pressing, rolling or hot isostatic pressing (in particular three-dimensional on core), or combinations of two or more thereof.

[0259] In the case of composite materials, bonding solutions are also possible. In particular, the reinforcement material (e.g., carbon fiber reinforced plastic (CFRP)) can be bonded to the barrier material using a bonding agent (in particular), an adhesive, for example, one or more organic polymers, especially resins. For example, a pipe made of barrier material can be externally wrapped with reinforcement material in resin. Curing can also take place at elevated temperatures, preferably at temperatures below 250°C.

[0260] If materials of the same type (e.g. glass powder) are to be used as a bonding agent to the barrier material, this can be applied, for example, in the form of a particle suspension (glass powder in / with a binder solution, e.g. polyvinyl butyral (PVB) in ethanol (EtOH)) or as a sol-gel.

[0261] In addition to impregnating the reinforcement material with the sol-gel, spraying processes are also possible.

[0262] The outside of a tube can then be wound. Its inside, however, as with resins, is primarily amenable to lamination techniques. In the case of particles and / or a sol-gel, one or more annealing steps are preferably provided, for example, sol-gel conversion, binder burnout, and / or densification of the composite. Annealing preferably takes place at temperatures below the glass transition temperature Tg of the barrier material. It is also possible for the winding of a tube's outside and the annealing to take place in parallel.

[0263] In order to achieve a particularly intimate bond between barrier material and reinforcement material, it may be preferable to first subject the barrier material to a surface treatment, in particular a chemical and / or physical pretreatment (for example with plasma) or the application of adhesion promoters (in particular primers).

[0264] When using carbon fibers, their tendency to degrade at elevated temperatures under normal atmospheres must be taken into account. Processing or thermal processes under a protective gas may be preferable.

[0265] Also according to the invention is a method for producing a glass or glass article of this invention, comprising the steps:

[0266] - Melting of the glass raw materials,

[0267] - Shaping a glass article

[0268] - Cooling the glass.

[0269] The forming of the glass may involve a drawing process, in particular a tube drawing process or a drawing process for flat glass or fibers. Cooling may be active cooling using a coolant, e.g., a cooling fluid, or passive cooling.

[0270] Particularly preferably, the forming process involves a flat glass process, for example, a drawing process. Such a process can be used to obtain glass layers or glass films. Such a design of the glass article or glass is particularly advantageous for achieving the desired low hydrogen permeability.

[0271] The invention also relates to a method for producing a glass using a coating process.

[0272] The invention also relates to a method for producing a combination material, in particular a material composite or a composite material comprising or consisting of a carbon- or silicon carbide-fiber-reinforced glass, using the glass according to the invention for the glass matrix. Uses and glass articles

[0273] Glass articles formed from the glass, such as glass tubes, are also according to the invention.

[0274] The invention also relates to a glass article comprising or consisting of the glass of the invention. Particularly when used in or as a barrier material, the glass article is sheet-like and thus not fibrous. A fibrous design of the glass article would be associated with an increase in hydrogen permeability, which is to be avoided according to the invention. Rather, the hydrogen permeability should be low. Therefore, the glass article of the invention is preferably not fibrous. Instead, a sheet-like design of the glass article is preferred. The glass article is preferably layered, for example in the form of a glass layer or a glass film. The glass article is therefore preferably in the form of a glass layer, in particular in the form of a glass film. The glass article is preferably a glass layer or a glass film.

[0275] The invention also relates to a combination material, for example a material composite, in particular a layered composite, which comprises or consists of the glass according to the invention and at least one further layer. The further layer can in particular comprise carbon fibers and / or silicon carbide fibers.

[0276] The present invention also relates to the use of the glass according to the invention for glass layers.

[0277] The invention also relates to the use of a glass or glass article of the invention in or as a barrier material of the wall of a hydrogen storage device, in particular a hydrogen storage device of the invention.

[0278] The invention also relates to the use of a glass or glass article of the invention in or as a barrier material of a combination material, in particular a combination material of the invention, the combination material comprising the barrier material and a reinforcing material.

[0279] The present invention also relates to the use of the glass according to the invention for fiber-reinforced glass.

[0280] The invention also relates to the use of the glass or combination material according to the invention, in particular material composite or composite material or layer composite in or as a hydrogen storage device, in particular as a barrier material for molecular hydrogen.

[0281] The hydrogen storage device of the present invention (in particular its wall) preferably comprises the combination material, in particular the composite material or the composite material of the present invention. The hydrogen storage device of the present invention preferably comprises the glass of the present invention, in particular in or as a barrier material of the combination material, in particular the composite material or the composite material of the wall.

[0282] The combination material, in particular the composite material or the composite material of the present invention, preferably comprises the glass of the present invention. The barrier material of the combination material, in particular the composite material or the composite material of the present invention, preferably comprises the glass of the present invention or consists of the glass of the present invention.

[0283] Description of the characters

[0284] Figure 1 shows a hydrogen storage device 11 of the invention in a preferred embodiment with a wall made of a combination material comprising an inner barrier layer 13 (i.e., facing the cavity 12) made of a barrier material and an outer reinforcement layer 14 made of a reinforcement material. The reinforcement layer 14 is provided continuously around the barrier layer 13. The hydrogen storage device comprises two valves 15 and 16 provided on opposite sides.

[0285] Figure 2 shows a further preferred embodiment of the invention in the form of a hydrogen storage device 21 with a cavity 22 and a wall comprising an inner barrier layer 23 made of a barrier material and an outer reinforcement layer 24 made of a reinforcement material. In contrast to Figure 1, in Figure 2 the reinforcement layer 24 is provided only on the long sides of the wall. No reinforcement layer 24 is provided on the short sides, where the valves 25 and 26 are also located. There, the wall is formed solely by the barrier layer 23.

[0286] Figure 3 shows two further embodiments of the invention in the form of a hydrogen storage device 31a and a hydrogen storage device 31b. The two hydrogen storage devices 31a and 31b are bottle-shaped and comprise a cavity (32a, 32b) in which hydrogen can be stored. The valves 35a and 35b are provided at the top, i.e., on the opposite side of the bottom (37a, 37b) provided at the bottom. In the hydrogen storage device designated 31a (left in Figure 3), a reinforcement layer 34a is arranged continuously around the barrier layer 33a. In contrast, the hydrogen storage device 31b is designed such that no reinforcement layer 34b is provided in the upper region, particularly near the valve 35b, so that the wall there is formed solely by the barrier layer 33b. Examples

[0287] The invention is further described below using selected examples.

[0288] Hydrogen storage

[0289] In a preferred embodiment of the invention, a hydrogen storage device according to the invention has a wall made of a combination material that encloses a cavity in which hydrogen can be stored. The combination material comprises an inner barrier layer made of a barrier material and an outer reinforcement layer made of a reinforcement material. The barrier layer is in the form of a sheet material. The reinforcement layer is arranged continuously around the barrier layer. The hydrogen storage device comprises two valves provided on opposite sides.

[0290] According to a further preferred embodiment of the invention, a hydrogen storage device is provided with a cavity for storing hydrogen and a wall comprising an inner barrier layer made of a barrier material and an outer reinforcement layer made of a reinforcement material. In this embodiment, the reinforcement layer is provided only on the long sides of the wall. No reinforcement layer is provided on the short sides, where the valves are also located. There, the wall is formed solely by the barrier layer.

[0291] According to a further embodiment of the invention, the hydrogen storage device is bottle-shaped and also comprises a cavity in which hydrogen can be stored. The valves are provided at the top, i.e., on the opposite side of the bottom provided at the bottom. The reinforcement layer can be arranged continuously around the barrier layer. However, the hydrogen storage device can also be designed such that no reinforcement layer is provided in the upper region, particularly near the valve, so that the wall there is formed solely by the barrier layer.

[0292] Combination material

[0293] A particularly preferred combination material of the present invention consists of a barrier material and a reinforcement material. In particular, the combination material is a layered composite of a barrier material and a reinforcement material. An exemplary barrier material and an exemplary reinforcement material are described in more detail below. Barrier material

[0294] Glass is particularly suitable as a barrier material.

[0295] The following tables list the compositions of some glasses in constituent phases, as well as the values ​​calculated according to the invention for density, GTE, packing density and ^-permeability per mol / (ms Pa).

[0296] The materials shown are generally suitable as barrier materials. However, their hydrogen permeability is comparatively high. Particularly problematic is the discernible trend whereby materials with lower hydrogen permeability exhibit a higher GTE and vice versa.

[0297] Materials that are particularly well suited for combination materials with the desired reinforcement materials due to their medium CTE are suboptimal in terms of their hydrogen permeability.

[0298] The materials shown in the following table are preferable because they combine a suitable GTE with very low hydrogen permeability.

[0299] Reinforcing material

[0300] The reinforcing material is, in particular, a fibrous material, preferably carbon fibers and / or silicon carbide fibers. The combination material is therefore preferably fiber-reinforced glass.

[0301] List of reference symbols

[0302] 11, 21 , 31a, 31b Hydrogen storage

[0303] 12, 22, 32a, 32b cavity

[0304] 12, 23, 33a, 33b barrier layer

[0305] 14, 24, 34a, 34b Reinforcing layer

[0306] 15, 16, 25, 26, 35a, 35b valve

[0307] 37a, 37b floor

Claims

Claims 1. Hydrogen storage comprising a cavity and a wall surrounding the cavity, • wherein the wall comprises a combination material comprising a barrier material and a reinforcing material, wherein the barrier material is in particular a sheet material, • the wall has a thickness of not more than 50 mm, and • where the base 10 logarithm of the hydrogen permeability p of the wall is less than -20,000, especially at a temperature of 473 K.

2. Hydrogen storage device according to claim 1, wherein the hydrogen storage device is a mobile hydrogen storage device, in particular a hydrogen tank as part of a vehicle.

3. Hydrogen storage device according to at least one of the preceding claims, wherein the wall has at least one opening.

4. Hydrogen storage device according to at least one of the preceding claims, wherein the total thickness variation of the wall is in a range of 0.1 to 10 mm.

5. Hydrogen storage device according to at least one of the preceding claims, wherein the wall has an inner layer and an outer layer.

6. Hydrogen storage device according to at least one of the preceding claims, wherein the hydrogen storage device comprises one or more valves.

7. Combination material, in particular combination material according to at least one of the preceding claims, comprising a barrier material and a reinforcing material, wherein the difference in the average thermal expansion coefficient of the barrier material and the reinforcing material in a range from 20°C to 300°C is at most 10.0 ppm / K.

8. Combination material according to claim 7, wherein the barrier material comprises glass and / or wherein the reinforcement material comprises carbon fibers and / or silicon carbide fibers.

9. Combination material according to at least one of claims 7 and 8, wherein the barrier material is configured in layers.

10. Combination material according to claim 9, wherein the barrier material is in the form of a film.

1. Combination material according to at least one of claims 7 to 10, wherein the Barrier material comprises a glass with the following components in the specified proportions (in mol%): where the sum of the molar fractions of the alkali metal oxides R2O and the alkaline earth metal oxides RO is equal to or greater than the sum of the molar fractions of B2O3 and AI2O3, where the composition of the glass is characterized by the following phases constituting the glass: and where the base 10 logarithm of the hydrogen permeability p calculated according to formula (10) is less than -20,000. Barrier material according to claim 11, wherein the glass has a GTE calculated according to formula (3) in a range of 3.5 to 9.5 ppm / K and / or the density p calculated according to formula (1) in a range of 2.20 to 2.70 g / cm 3 and / or the packing density x calculated according to formula (2) is at least 0.49 and / or the elastic modulus E calculated according to formula (8) is at least 60 GPa. Barrier material according to at least one of claims 11 to 12, wherein the proportion of the residue in the glass is at most 3.0 mol% and / or wherein the proportion of MgO is greater than the proportion of Li2O and / or wherein the proportion of malinkoite is at least 1.0 mol% and / or wherein the proportion of cordierite is at least 1.0 mol% and / or wherein the sum of the proportions of cordierite and malinkoite is in a range from 50 to 100 mol%.

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