Storage system for storing a cryogenic medium, and fuel cell system

Abstract

The invention relates to a storage system (1) for storing a cryogenic medium for a fuel cell system comprising a pressure vessel (3) for holding the medium; a gas delivery line (4) for filling / removing the gaseous medium from the pressure vessel; and a liquid delivery line (5) for filling / removing the liquid medium from the pressure vessel, wherein the gas delivery line and the liquid delivery line are coupled to a controllable shut-off device (6); wherein the gas delivery line and / or the liquid delivery line have a heating element (7) inside the pressure vessel for heating the medium. The invention also relates to a fuel cell system.

Description

[0001] Description

[0002] title

[0003] Storage system for storing a cryogenic medium and fuel cell system

[0004] The present invention relates to a storage system for storing a cryogenic medium for a fuel cell system and a fuel cell system with such a storage system.

[0005] State of the art

[0006] Fuel cell systems (FCS) typically use oxygen from the ambient air as an oxidant to react with hydrogen in the fuel cell to produce water or water vapor, thereby generating electrical power through electrochemical conversion. The hydrogen required for this is stored in special tanks under high pressure and at low temperatures. The hydrogen is usually present partly in liquid form in the storage container and partly in gaseous form.

[0007] In order to remove the medium from the storage tank, it is known to heat the removed medium outside the storage tank and to return a partial flow of the heated medium back into the storage tank, so that the medium around the returned partial flow in the tank is also heated and therefore evaporated.

[0008] For example, the document DE 10 2020 206 689 A describes a storage system for storing hydrogen, comprising a first heat exchanger arranged outside the storage container, fluidically connected to the gas extraction line, for heating the medium, and an inner tank heat exchanger arranged downstream of the first heat exchanger and inside the storage container, for heating the liquid medium in the storage container. Disclosure of the Invention

[0009] The invention provides a storage system for storing a cryogenic medium for a fuel cell system and a fuel cell system having the features of the independent patent claims.

[0010] According to a first aspect, the invention relates to a storage system for storing a cryogenic medium for a fuel cell system, comprising a pressure vessel for receiving the medium; a gas delivery line for filling / removing the gaseous medium from the pressure vessel; and a liquid delivery line for filling / removing the liquid medium from the pressure vessel, wherein the gas delivery line and the liquid delivery line are coupled to a controllable shut-off device; wherein the gas delivery line and / or the liquid delivery line within the pressure vessel has a heating element for heating the medium.

[0011] According to a second aspect, the invention relates to a fuel cell system with a refueling device and a consumer, which are fluidly connected to the storage system.

[0012] One idea underlying the present invention is to provide a heat energy generating element or a heating element on at least one existing media conduit, i.e., a supply and / or discharge line or a gas and / or liquid conveying line, of the storage system. This means that the inner tank or pressure vessel has at least one heat energy generating element on at least one existing media conduit into and / or out of the tank interior. The supply and / or discharge line conveys the medium into and / or out of the tank interior or the pressure vessel.

[0013] Advantageously, an existing resource, i.e., the gas and / or liquid feed line present in known storage systems, can be used to evaporate the liquid medium or heat the gaseous medium in a storage and / or line element of the fuel cell system. This means that the heating of the tank contents or pressure vessel contents through the existing supply and / or discharge line represents a functional expansion of the storage system. This allows for the elimination of additional interfaces. Furthermore, the effectiveness of the necessary heat input can be improved.

[0014] A further advantage is the positioning of the heating element on the media line to the liquid phase or gas phase, i.e., on the gas feed line or the liquid feed line. By positioning the heating element on the liquid feed line, a large change in pressure in the pressure vessel can be achieved with a small amount of energy. By positioning the heating element on the gas feed line, a small change in pressure can be achieved with a small amount of energy, thus improving control quality.

[0015] Advantageous embodiments and further developments emerge from the further subclaims and from the description with reference to the figures of the drawing.

[0016] According to a further development of the storage system, the heating element is arranged at least in sections along a flow path of the medium on the gas delivery line. Preferably, the heating element is arranged in an end section or a middle section of the gas delivery line. Thus, the heating of the medium can be provided directly at the location where it is desired.

[0017] The cryogenic medium is, for example, hydrogen.

[0018] According to a further development of the storage system, the heating element is arranged at least in sections along a flow path of the medium on the liquid conveying line. Preferably, the heating element is arranged in an end section or a middle section of the liquid conveying line. Thus, the heating of the medium can be provided directly at the location where it is desired. According to a further development of the storage system, the heating element is designed as an electrical resistance heater.

[0019] According to a further development of the storage system, the gas conveying line and / or the liquid conveying line has at least two different chamber devices, wherein the heating element is provided in one of the at least two chamber devices through which the medium cannot flow. In this way, the heating element can be protected from contact with the cryogenic medium.

[0020] According to a further development of the storage system, the heating element contains an electrical cable device connected to a power source to supply power to the heating element. Thus, the power supply can be provided via a cable or the cable device, which can be protected from hydrogen inside a multi-chamber system of the media guide, for example, in one of at least two chamber devices.

[0021] According to a further development, the storage system comprises a double-walled container for accommodating the cryogenic medium, wherein the pressure vessel forms the inner container of the double-walled container, and the double-walled container additionally comprises an outer container surrounding the pressure vessel. Thus, the storage system can even better insulate the cryogenic medium from its surroundings.

[0022] According to a further development, the storage system further comprises a control device that is electronically connected to the heating element and configured to increase the pressure within the pressure vessel by heating the medium. Thus, the medium can be heated precisely, for example, by controlling the heating element of the liquid delivery line for a large change in pressure. Alternatively or additionally, the heating element of the gas delivery line can be controlled, for example, for a small change in pressure.

[0023] According to a further development, the storage system further comprises a first heat exchanger arranged outside the pressure vessel, fluidly connected to the gas delivery line, for heating the medium, and an inner-tank heat exchanger arranged downstream of the first heat exchanger and inside the pressure vessel, for heating the liquid medium in the pressure vessel. In this way, the liquid medium can be heated via the inner-tank heat exchanger in addition to the heating element.

[0024] In other words, the structure of the pressure vessel can be described as follows: The inner tank, or pressure vessel, consists of a pressure hull coated on the inside, also called a liner, a heat radiation shield or third wall layer, and a carbon fiber fabric surrounding the pressure hull.

[0025] Short description of the drawings

[0026] The invention is explained below with reference to the figures of the drawings. The figures show:

[0027] Figure 1 shows a storage system according to an embodiment of the invention.

[0028] In all figures, identical or functionally equivalent elements and devices are provided with the same reference numerals. The numbering of process steps serves the purpose of clarity and is generally not intended to imply a specific chronological order. In particular, several process steps can be performed simultaneously.

[0029] Description of the embodiments

[0030] Further advantages, features and details of the invention will become apparent from the following description, in which various embodiments are described in detail with reference to the drawing.

[0031] Figure 1 shows a storage system 1. The storage system 1 is particularly suitable for storing a cryogenic medium 2a; 2b, for example, hydrogen, for a fuel cell system. Typically, the hydrogen exists in a gas phase 2a and a liquid phase 2b.

[0032] The storage system 1 comprises a pressure vessel 3 for holding the hydrogen 2a; 2b. By way of example, the storage system 1 here comprises a double-walled vessel for holding the cryogenic hydrogen 2a; 2b, wherein the pressure vessel 3 forms the inner vessel of the double-walled vessel, and the double-walled vessel additionally comprises an outer vessel 9 surrounding the pressure vessel 3.

[0033] Between the outer container 9 and the inner container 3, spacer devices 14 are also arranged in sections in order to position and fix the two shells of the double-walled container relative to each other.

[0034] The storage system 1 further comprises a gas delivery line 4 for filling or removing the gaseous hydrogen 2a from the pressure vessel 3 and a liquid delivery line 5 for filling or removing the liquid hydrogen 2b from the pressure vessel 3. The gas delivery line 4 is designed, for example, to remove the gaseous hydrogen 2a from the pressure vessel 3, so that the free end of the gas delivery line 4 ends above the liquid surface, near the ceiling of the pressure vessel 3, in the pressure vessel 3. The liquid delivery line 5 is designed to remove the liquid hydrogen from the pressure vessel 3, so that the free end of the liquid delivery line 5 ends below the liquid surface, near the bottom of the pressure vessel 3, in the pressure vessel 3.

[0035] The terms “ceiling” and “floor” refer to the usual installation position of the pressure vessel, for example in a moving or flying transport device, whereby gravity acts towards the floor of the pressure vessel during normal operation of the transport device.

[0036] The gas delivery line 4 and the liquid delivery line 5 are coupled to a controllable shut-off device 6. In this embodiment, the controllable shut-off device 6 comprises a first controllable shut-off valve 6a arranged in the gas delivery line 4 and a second controllable shut-off valve 6b arranged in the liquid delivery line 5. Both shut-off valves are located outside the pressure vessel 3. In Fig. 1, the shut-off valves are located inside the outer container 9, i.e., between the pressure vessel 3 and the outer container 9 of the double-walled container, in particular in a vacuum space.

[0037] However, the shut-off device 6 is not limited to this embodiment, but can alternatively form a controllable switching valve with a first inlet on the gas delivery line 4 and a second inlet on the liquid delivery line 5.

[0038] The storage system 1 further comprises a control device 10, which is electronically connected to the heating element 7 and is configured to increase a pressure within the pressure vessel 3 by heating the hydrogen 2a; 2b.

[0039] The shut-off valves 6a, 6b can also be controlled by the control device 10, which is arranged, for example, in the vacuum chamber, as shown here, or outside the entire double-walled container. The flow through the shut-off valves can preferably not only be interrupted or opened, but also reduced.

[0040] The gas delivery line 4 or the liquid delivery line 5 has a heating element 7 within the pressure vessel 3 for heating the hydrogen 2a; 2b. For example, in Figure 1, the gas delivery line 4 and the liquid delivery line 5 have a heating element 7, which is designed as an electrical resistance heater.

[0041] The first heating element 7 is arranged here in an end section of the gas conveying line 4. Alternatively or additionally, the first heating element 7 can be arranged in a central section of the gas conveying line 4. Furthermore, the second heating element 7 is arranged here in an end section of the liquid conveying line 5.

[0042] Alternatively or additionally, the second heating element 7 can be arranged in a central section of the liquid conveying line 5. The gas conveying line 4 and the liquid conveying line 5 each have two different chamber devices. For example, the heating element 7 is provided in the lower of the two chamber devices, whereby the lower chamber device of the gas conveying line 4 or the liquid conveying line 5 cannot be passed through by the hydrogen. This means that the hydrogen flows, for example, through the upper chamber device without coming into contact with the heating element 7.

[0043] An electrical cable device 8, which is connected to a power source for supplying power to the heating element 7, is also arranged here in the lower chamber device of the gas conveying line 4 or the liquid conveying line 5.

[0044] The pressure vessel 3 can also be refueled from a refueling device 13 of a fuel cell system via the gas delivery line 4 and / or the liquid delivery line 5, preferably also via the first shut-off valve 6a and / or the second shut-off valve 6b.

[0045] The gas conveying line 4 and the liquid conveying line 5 are combined into a common line after the two shut-off valves 6a, 6b. A rectifying valve, in particular a check valve 15, can be arranged in the gas conveying line 4, so that only the flow direction from the first shut-off valve 6a to a first heat exchanger 11 is permitted, while the opposite direction is blocked.

[0046] The gas conveying line 4 and the liquid conveying line 5 are fluidly connected in the form of the common line to the first heat exchanger 11 arranged outside the pressure vessel 3, for example between the pressure vessel 3 and the outer vessel 9 of the double-walled vessel, for heating the withdrawn medium.

[0047] Downstream of the first heat exchanger 11, an internal tank heat exchanger 12 is arranged within the pressure vessel 3 for heating the liquid medium in the pressure vessel 3. The heated hydrogen drawn from the pressure vessel flows through this internal tank heat exchanger 12. The heating at the internal tank heat exchanger 12 partially heats and evaporates the liquid hydrogen in the pressure vessel 3.

[0048] For example, the pressure in the pressure vessel 3 can be regulated by means of the first and second shut-off valves 6a, 6b. The control device 10 can be configured to control the pressure in the pressure vessel 3 during the withdrawal of hydrogen by selectively opening the first shut-off valve 6a and / or the second shut-off valve 6b, so that the hydrogen is selectively withdrawn from the pressure vessel 3 via the gas delivery line 4 and / or the liquid delivery line 5.

[0049] Downstream of the inner tank heat exchanger 12 and outside the pressure vessel 3, a second heat exchanger 16 for heating the hydrogen can be arranged.

[0050] The medium withdrawn via the gas delivery line 4 and / or the liquid delivery line 5 is supplied to a consumer 14, in particular a fuel cell, downstream of the inner tank heat exchanger 12. A third shut-off valve 17 is arranged, for example, between the second heat exchanger 16 and the consumer 14.

[0051] Although the present invention has been explained above using exemplary embodiments, it is not limited thereto but can be modified in a variety of ways. In particular, combinations of the above embodiments are also conceivable.

Claims

Claims 1. A storage system (1) for storing a cryogenic medium (2a; 2b) for a fuel cell system, comprising: a pressure vessel (3) for receiving the medium (2a; 2b); a gas delivery line (4) for filling / removing the gaseous medium (2a) from the pressure vessel (3); and a liquid delivery line (5) for filling / removing the liquid medium (2b) from the pressure vessel (3), wherein the gas delivery line (4) and the liquid delivery line (5) are coupled to a controllable shut-off device (6); wherein the gas delivery line (4) and / or the liquid delivery line (5) has a heating element (7) within the pressure vessel (3) for heating the medium (2a; 2b).

2. Storage system (1) according to claim 1, wherein the heating element (7) is arranged at least in sections, in particular in an end section or a middle section of the gas delivery line (4), along a flow path of the medium on the gas delivery line (4).

3. Storage system (1) according to claim 1 or 2, wherein the heating element (7) is arranged at least in sections, in particular in an end section or a middle section of the liquid conveying line (5), along a flow path of the medium of the liquid conveying line (5).

4. Storage system (1) according to one of the preceding claims, wherein the heating element (7) is designed as an electrical resistance heater.

5. Storage system (1) according to one of the preceding claims, wherein the gas conveying line (4) and / or the liquid conveying line (5) has at least two different chamber devices, wherein the Heating element (7) is provided in one of the at least two chamber devices through which the medium cannot flow.

6. Storage system (1) according to one of the preceding claims, wherein the heating element (7) contains an electrical cable device (8) which is connected to a power source for supplying power to the heating element (7).

7. Storage system (1) according to one of the preceding claims, wherein the storage system (1) comprises a double-walled container for receiving the cryogenic medium (2a; 2b), wherein the pressure vessel (3) forms the inner container of the double-walled container and the double-walled container additionally comprises an outer container (9) surrounding the pressure vessel (3).

8. Storage system (1) according to one of the preceding claims, further comprising a control device (10) which is electronically connected to the heating element (7) and is configured to increase a pressure within the pressure vessel (3) by heating the medium (2a; 2b).

9. Storage system (1) according to one of the preceding claims, further comprising a first heat exchanger (11) arranged outside the pressure vessel (3) and fluidly connected to the gas delivery line (4) for heating the medium and an inner tank heat exchanger (12) arranged downstream of the first heat exchanger (11) and inside the pressure vessel (3) for heating the liquid medium (2b) in the pressure vessel (3).

10. Fuel cell system with a storage system (1) according to one of the preceding claims and with a refueling device (13) and a consumer (14) which are fluidically connected to the storage system (1).

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