Tank system for storing hydrogen

Abstract

The presented invention relates to a tank system (100) for storing hydrogen, wherein the tank system comprises at least one tank (101), wherein the at least one tank (101) has a useful volume (105) surrounded by a shell (103), wherein a porous nanomaterial (107) is arranged in the useful volume (105), which is configured to reversibly adsorb hydrogen introduced into the useful volume (107).

Description

[0001] The presented invention relates to a tank system for storing hydrogen, a transport system and a filling station for filling the presented tank system. State of the art

[0002] Known tank systems are based on mechanically extremely strong shell structures, which are filled with correspondingly high pressures of, for example, 700 bar in order to maximize the density in the shell structure and, as a result, to store a particularly large amount of hydrogen.

[0003] Such tank systems are accordingly heavy and space-intensive.

[0004] Furthermore, the load-bearing capacity of such tank systems requires a characteristic cylindrical shape, which is suboptimal for a space-optimized arrangement of tanks in a transport system, such as a vehicle.

[0005] As a result, these systems offer limited volumetric density. Disclosure of the invention

[0006] Within the scope of the invention presented, a tank system, a transport system, and a filling station for refueling the tank system are presented. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the tank system according to the invention naturally also apply in connection with the transport system or the filling station according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0007] The invention presented serves in particular to provide a possibility for a space- and cost-efficient tank system.

[0008] Thus, according to a first aspect of the invention presented, a tank system for storing hydrogen is presented.

[0009] The presented tank system comprises at least one tank, wherein the at least one tank has a useful volume surrounded by a shell and wherein a porous nanomaterial is arranged in the useful volume, which is configured to reversibly adsorb hydrogen introduced into the useful volume.

[0010] The presented invention is based on a porous nanomaterial used to reversibly adsorb hydrogen by utilizing weak attractive forces between molecules, such as van der Waals forces. This means that hydrogen is stored in the nanomaterial under pressure and, when the pressure drops, is released from the nanomaterial, especially without the input of energy, to escape from the tank of the presented tank system.

[0011] Due to the nanomaterial provided according to the invention, there is a disproportionate increase in density in the tank with increasing pressure, so that more hydrogen can be stored at lower pressure compared to a conventional or known tank.

[0012] Accordingly, the maximum pressure required or sensible for filling the proposed tank system is considerably lower than for known tanks without porous nanostructures, since the adsorption capacity physically decreases above a certain pressure. This means that the respective tanks of the proposed tank system must be designed to be less mechanically stable than known tanks, so that the tanks of the proposed tank system can, for example, have a shape different from a cylinder and / or be lighter.

[0013] Furthermore, the tank system presented enables a larger amount of storable hydrogen compared to known tank systems while requiring the same amount of space.

[0014] It may be provided that the nanomaterial comprises graphene and / or a metal-organic framework (MOF).

[0015] Graphene, in particular, has proven to be a suitable nanomaterial for the reversible adsorption of hydrogen. For this purpose, the nanomaterial can be incorporated, for example, in the form of a foam or powder, into a shell forming at least one tank of the proposed tank system. This means that existing tanks, for example, can be converted to the proposed tank system.

[0016] It can further be provided that the at least one tank is configured to be filled with hydrogen up to a pressure of up to 200 bar, advantageously between 120 bar and 150 bar.

[0017] Tests have shown that the maximum density of hydrogen stored in the tank of the proposed tank system is achieved in a range between 120 bar and 150 bar. Accordingly, limiting the maximum pressure for hydrogen storage to a value between 120 bar and 150 bar provides greater design freedom compared to the previously required maximum pressure of 700 bar.

[0018] It can further be provided that the at least one tank is configured to be filled with hydrogen at a pressure between a lower limit of 1 bar, preferably 10 bar, and an upper limit of 200 bar, preferably 150 bar, particularly preferably 125 bar.

[0019] Furthermore, tests have shown that the tank provided according to the invention is capable of storing or providing a significant amount of hydrogen even at a pressure below 10 bar, and even between 1 bar and 10 bar. Accordingly, the use of the proposed tank system is technically feasible and possible starting at a pressure of 1 bar, although the tank's shell may require a somewhat higher minimum pressure.

[0020] It can further be provided that the shell consists of a fiber-reinforced material cured with a resin, wherein the resin comprises graphene. This allows the amount of fiber-reinforced material to be reduced.

[0021] The lower pressure in the tank allows the use of a resin that is leak-proof against hydrogen, eliminating the need for a liner, as typically used in fiber-reinforced Type IV tanks for hydrogen storage. Accordingly, the tank provided by the invention can be a Type V tank, manufactured without a liner or liner-free. This allows such a tank to hold a slightly higher amount of hydrogen and also be more cost-effective. Under certain circumstances, it can also contribute to making the tanks more recyclable.

[0022] However, the use of tanks of types I to IV is also possible.

[0023] It can further be provided that the tank system comprises a compressor which is fluidly coupled to the at least one tank and which is configured to compress hydrogen flowing from the at least one tank to a predetermined pressure.

[0024] In order to make hydrogen provided from the tank provided according to the invention accessible or processable in a high-pressure system, such as a direct hydrogen injection system, the proposed tank system can include a compressor. The compressor can, for example, be a mechanical compressor driven by an engine. A mechanical compressor can be particularly robust.

[0025] As an alternative to a mechanical compressor, the compressor can be an electrochemical compressor. In this case, the hydrogen from the tank is oxidized on the anode side by applying a direct current in an electrochemical cell similar to a PEM electrolysis cell. This is then transported to the cathode side, thereby increasing the pressure on the cathode side. With an electrochemical compressor, pressures of over 700 bar can be achieved with an efficiency of around 80%.

[0026] It may further be provided that the tank system comprises a control unit configured to activate the compressor in the event that a pressure in the at least one tank falls below a predetermined threshold value.

[0027] A control unit for activating the compressor may, for example, comprise a control valve and / or a computing unit, such as a processor or a control unit that is in communicative contact with a pressure sensor.

[0028] It can further be provided that the at least one tank is configured to store cryogenic hydrogen.

[0029] For storing cryogenic hydrogen, the tank can, for example, be thermally insulated. By storing cryogenic hydrogen, a particularly large amount of hydrogen can be stored in the tank, which could be further increased using the nanomaterial provided by the invention.

[0030] According to a second aspect, the presented invention relates to a transport system.

[0031] The presented transport system comprises a drive and a possible design of the presented tank system, wherein the tank system is configured to supply the drive with hydrogen.

[0032] The transport system presented can be, for example, a vehicle, an aircraft or a ship.

[0033] The drive of the proposed transport system can, for example, comprise a fuel cell system and / or a hydrogen engine. For example, the hydrogen engine can be a direct-injection hydrogen engine and / or a port-injection hydrogen engine with a low injection pressure of, for example, up to 15 bar.

[0034] According to a third aspect, the presented invention relates to a filling station for filling a possible embodiment of the presented tank system with hydrogen, wherein the filling station is configured to fill the at least one tank up to a predetermined maximum pressure, wherein the maximum pressure is less than 200 bar, preferably between 125 bar and 150 bar.

[0035] Advantages that are described in detail for the tank system for storing hydrogen according to the first aspect of the invention apply equally to the transport system according to the second aspect of the invention and the filling station for filling a possible embodiment of the presented tank system with hydrogen according to the third aspect of the invention. Drawings

[0036] Further advantages, features, and details of the invention will become apparent from the following description, which describes exemplary embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination.

[0037] They show schematically: Fig. 1 a representation of a possible design of the presented tank system, Fig. 2 a comparison of hydrogen storage capacity between different tank systems, Fig. 3 a representation of a possible design of the proposed transport system, and Fig. 4 a representation of a possible design of the presented petrol station. Description of the embodiments

[0038] In Fig. 1 shows a tank system 100. The tank system 100 comprises a tank 101 having a usable volume 105 surrounded by a shell 103.

[0039] A porous nanomaterial 107 is arranged in the useful volume 105 and is configured to reversibly adsorb hydrogen introduced into the useful volume 105.

[0040] Due to the nanomaterial 107, a particularly large amount of hydrogen or hydrogen with a density that is greater than in a tank that does not contain any nanomaterial and is filled with hydrogen at a pressure between 1 bar and 200 bar, as described in Fig. 2 is evident.

[0041] In Fig. 2 shows a diagram 110 which spans on its ordinate a filling quantity of hydrogen in [kg] and on its abscissa a pressure in [bar].

[0042] A first curve 112 corresponds to a filling quantity of a possible design of the presented tank system.

[0043] A second curve 114 corresponds to a filling quantity of a tank system without nanomaterial.

[0044] While the tank system underlying the first curve 112 stores 5.5 kg of hydrogen at a pressure of approximately 125 bar (usable hydrogen quantity 2.8 kg from 10 to 125 bar), the tank system underlying the second curve 114 can only store 2.1 kg of hydrogen at a pressure of 700 bar (usable hydrogen quantity 1.8 kg from 50 to 700 bar).

[0045] In Fig. 3 shows a transport system 200 in the form of a vehicle.

[0046] The transport system 200 comprises a drive 201 in the form of a hydrogen engine, which is supplied with hydrogen by a hydrogen direct injection system 203.

[0047] The tank system 100 according to Fig. 1 supplies the hydrogen direct injection system 203 with hydrogen.

[0048] The hydrogen direct injection system 203 must be supplied with a supply pressure of approximately up to 150 bar. To maintain this supply pressure, the tank system 100 of the transport system 200 includes, for example, an electrochemical compressor 205, which is activated when the pressure in the tank 101 drops below 60 bar.

[0049] To ensure a continuous supply to the hydrogen direct injection system 203, the tank system 100 of the transport system 200 includes an optional intermediate storage unit 207 in which hydrogen is temporarily stored at 60 bar. For this purpose, the intermediate storage unit 207 is fluidly coupled to both the tank 101 and the compressor 205.

[0050] To activate the compressor 205, for example, a computing unit 209 and / or a switching valve 211 can be used.

[0051] In Fig. 4 shows a gas station 300. The gas station 300 comprises a supply station 301, which is configured to supply, for example, the tank system 100 according to Fig. 1 to be filled up to a specified maximum pressure.

[0052] For this purpose, the gas station 300 can include a sensor or an interface by means of which data that specifies the maximum pressure is determined. For example, a code arranged on the tank system 100 and encoding the maximum pressure can be read or transmitted from the tank system 100 to a computing unit of the gas station 300.

Claims

[1] Tank system (100) for storing hydrogen, The tank system includes: - at least one tank (101), wherein the at least one tank (101) has a useful volume (105) surrounded by a shell (103), wherein a porous nanomaterial (107) is arranged in the useful volume (105), which is configured to reversibly adsorb hydrogen introduced into the useful volume (107). [2] Tank system (100) according to claim 1, characterized by that the nanomaterial (107) comprises graphene and / or a metal-organic framework (MOF). [3] Tank system (100) according to claim 1 or 2, characterized by that the at least one tank (101) is configured to be filled with hydrogen up to a pressure of up to 200 bar, advantageously between 125 bar and 150 bar. [4] Tank system (100) according to one of the preceding claims, characterized bythat the at least one tank (101) is configured to be filled with hydrogen at a pressure between a lower limit of 1 bar, preferably 10 bar, and an upper limit of 200 bar, preferably 150 bar, particularly preferably 125 bar. [5] Tank system (100) according to one of the preceding claims, characterized by that the shell (103) consists of a fiber-reinforced material cured with a resin, the resin comprising graphene. [6] Tank system (100) according to one of the preceding claims, characterized by in that the tank system (100) comprises a compressor (205) fluidly coupled to the at least one tank (101) and configured to compress hydrogen flowing from the at least one tank (101) to a predetermined pressure level. [7] Tank system (100) according to claim 6, characterized by that the compressor (205) is a mechanical compressor or an electrochemical compressor. [8] Tank system (100) according to claim 6 or 7, characterized by in that the tank system (100) comprises a control unit (209) configured to activate the compressor (205) in the event that a pressure in the at least one tank (101) falls below a predetermined threshold value. [9] Tank system (100) according to one of the preceding claims, characterized by that the at least one tank (100) is configured to store gaseous hydrogen, in particular cryogenic hydrogen. [10] Transport system (200), wherein the transport system (200) comprises: - a drive (201), - a tank system (100) according to one of the preceding claims, wherein the tank system (100) is configured to supply the drive (201) with hydrogen. [11] Filling station (300) for filling a tank system (100) according to one of claims 1 to 9 with hydrogen, wherein the filling station (300) is configured to fill the at least one tank (101) up to a predetermined maximum pressure, wherein the maximum pressure is less than 200 bar, preferably between 125 bar and 150 bar.

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