DE102015219985A1 - Cryogenic pressure vessel system for storing fuel gas - Google Patents

Abstract

It is a cryogenic pressure vessel system for storing gas for a fuel cell, in particular for a motor vehicle, comprising a cryogenic pressure vessel (10) having an inner container (30) and an outer container (20), wherein between the inner container (30) and the outer container (20) at least partially an evacuated space (25) is arranged, shown, wherein the inner container (30) encloses an inner space (32) for storing the gas, further comprising a heating device (60) for heating the gas in the pressure vessel (10) wherein the heating device (60) is disposed outside the interior (32) of the inner container (30).

Description

The invention relates to a cryogenic pressure vessel system, a motor vehicle having such a pressure vessel system and a method for increasing the temperature of a gas in a cryogenic pressure vessel.

Cryogenic pressure vessel systems are known in the art. They include cryogenic pressure vessels. Such a pressure vessel comprises an inner container as well as an outer container surrounding it to form a super-isolated (eg evacuated) (intermediate) space. Cryogenic pressure vessels or pressure tanks are used, for example, for motor vehicles in which a fuel or fuel which is gaseous under ambient conditions is cryogenically stored and thus substantially in the liquid or supercritical state of aggregation with a significantly higher density compared to the ambient conditions. Therefore, highly effective insulation sheaths (eg vacuum envelopes) are provided. For example, the EP 1 546 601 B1 such a pressure vessel.

Since the removal of gas from the pressure vessel, the pressure and the temperature of the (residual) gas in the pressure vessel decreases, the (residual) gas must be heated in the pressure vessel to reach a pressure necessary for removal from the pressure vessel. This is usually done by a tank heat exchanger. The tank heat exchanger is arranged in the interior of the Innbehälters and by a warm medium (eg, already heated gas) flows through to heat the gas in the pressure vessel and thus to increase the pressure.

A disadvantage of this type of heat supply is that the pressure vessel system is constructed technically complex. In addition, the supply and return of the medium in the tank heat exchanger in the interior of the pressure vessel must be gas-tight. Also, complex welding work is necessary for the arrangement of the tank heat exchanger in the interior of the inner container. As a result, the manufacturing costs and production costs of the pressure vessel system increase. In addition, the diameter of the heat exchange is limited by the size of the port of the pressure vessel, whereby the area for heat exchange between the tank heat exchanger and the gas in the inner container of the pressure vessel is limited upwards. Another disadvantage is that the tank heat exchanger has a high span and a low resistance moment, whereby the operational stability of the pressure vessel system is low. In the event of major vibrations, the tank heat exchanger may leak or be released from its intended position.

It is an object of the technology disclosed herein to reduce or eliminate the disadvantages of the prior art solutions. Other objects arise from the beneficial effects of the technology disclosed herein.

The object (s) is / are solved by the subject matter of claim 1, the subject of claim 9 and the subject of claim 10. The dependent claims are preferred embodiments.

Thus, the object is achieved by a cryogenic pressure vessel system for storing gas for a fuel cell, in particular for a motor vehicle comprising a cryogenic pressure vessel, which has an inner container and an outer container, wherein between the inner container and the outer container at least partially an evacuated space is arranged solved wherein the inner container encloses an inner space for storing the gas, further comprising a heater for heating the gas in the pressure container, the heater being disposed outside the inner space of the inner container.

An advantage of this is that the pressure vessel system is technically simple. In addition, no tank heat exchanger in the interior of the inner container is needed to increase the temperature and consequently the pressure of the gas in the pressure vessel. Thus, the pressure vessel system or the inner container can be completed easily technically gas-tight. There are no elaborate welding required for the production of the pressure vessel system. Moreover, the amount of heat input or the temperature increase rate is not limited by the size of the port or the inlet and outlet of the pressure vessel. Another advantage is that the temperature and consequently the pressure in the pressure vessel can be increased technically simply and quickly. In this way, a temperature and a pressure in the pressure vessel can be technically easily made, so that the gas can be easily removed from the pressure vessel. In addition, more gas in the pressure vessel system can be stored, since the usual tank heat exchanger within the pressure vessel, which is not required in the present pressure vessel system, reduces the storage volume of the pressure vessel for gas. In addition, the pressure vessel system has a low weight (inter alia, since no tank heat exchanger inside the inner container is needed).

The heating device may be an electric heater. The advantage of this is that the heat supply to the gas in the pressure vessel is independent of the withdrawal flow of the gas from the pressure vessel. Also no piping is necessary, which is needed for the flow and return of a medium to a heat exchanger. Consequently, this also reduces the manufacturing costs and the technical complexity.

The inner container may have an outer shell, in particular comprising a composite material, preferably carbon fiber reinforced plastic, and an inner shell, in particular comprising a metal or a metal alloy, preferably aluminum, wherein the heating device between the inner shell of the inner container and the outer shell of the inner container is arranged. An advantage of this is that the heating device is particularly well protected against (mechanical) damage. Another advantage of this is that the heater does not occupy any space within the inner container. Thus, more gas can be stored in the inner container.

The inner container may comprise an outer shell, in particular comprising a composite material, preferably carbon fiber reinforced plastic, and an inner shell, in particular comprising a metal or a metal alloy, preferably aluminum, wherein the inner shell comprises the heating device. An advantage of this is that the pressure vessel system is technically particularly simple. In addition, the heating device is particularly well protected against (mechanical) damage. Also, no space within the inner container is occupied by the heating device, so that more gas can be stored in the inner container.

In one embodiment, the inner container has an outer shell, in particular comprising a composite material, preferably carbon fiber reinforced plastic, and an inner shell, in particular comprising a metal or a metal alloy, preferably aluminum, wherein the heating device is arranged on the outer surface of the outer shell of the inner container. An advantage of this is that the heater does not occupy any space inside the inner container. Thus, more gas can be stored in the inner container. In addition, the heating device can be arranged technically simple.

The heating device may be configured such that the heating device can be flowed through by a fluid for heating the gas in the pressure vessel, which has a higher temperature in comparison to the temperature of the gas in the pressure vessel. An advantage of this is that waste heat z. B. the fuel cell can be used to heat the gas in the pressure vessel system. In addition, the fluid, which is for example taken from the pressure vessel and already heated gas and / or cooling liquid of the fuel cell, is cooled by the passage through the heating device.

The heating device may be detachably arranged at the inlet and outlet of the inner container. One advantage of this is that the heating device is technically easy to check for its functionality. In addition, the heating device can be easily replaced technically.

The heating device may substantially completely enclose the inner container. As a result, a particularly rapid and uniform heating of the inner container is possible. Consequently, mechanical stresses in the inner container are substantially prevented.

The object is also achieved by a motor vehicle with a pressure vessel system described above.

The object is also achieved by methods for increasing the temperature of a gas for a fuel cell in a cryogenic pressure vessel, in particular in a motor vehicle, wherein the pressure vessel has an inner container and an outer container, wherein the inner container encloses an inner space for storing the gas, wherein a Heating device outside the interior of the inner container is heated to increase the temperature of the gas in the interior of the inner container. An advantage of this is that no tank heat exchanger is needed in the interior of the inner container to increase the temperature and consequently the pressure of the gas in the pressure vessel. Thus, a pressure vessel system or an inner container can be used, which are technically easily sealed gas-tight. Moreover, the amount of heat input or the temperature increase rate is not limited by the size of the port or the inlet and outlet of the pressure vessel. Another advantage is that the temperature and consequently the pressure in the pressure vessel can be increased technically simply and quickly. In this way, a temperature and a pressure in the pressure vessel can be technically easily made, so that the gas can be easily removed from the pressure vessel. In addition, a pressure vessel can be used, in which more gas can be stored, since the conventional tank heat exchanger within the pressure vessel, which is not required in the present pressure vessel system, reduces the storage volume of the pressure vessel for gas.

The heating device may comprise one or more heating coils, one or more heating bands (eg band-shaped heating element) and / or one or more heating elements.

The technology disclosed herein relates to a cryogenic pressure vessel. The cryogenic pressure vessel or pressure tank can store fuel in the liquid or supercritical state of aggregation. A supercritical state of aggregation is a thermodynamic state of a substance which has a higher temperature and a higher pressure than the critical point. The critical point denotes the thermodynamic state in which the densities of gas and liquid of the substance coincide, that is, it is single-phase. While one end of the vapor pressure curve in a pT diagram is marked by the triple point, the critical point represents the other end. For hydrogen, the critical point is 33.18 K and 13.0 bar. A cryogenic pressure vessel is particularly suitable for storing the fuel at temperatures significantly below the operating temperature (meaning the temperature range of the vehicle environment in which the vehicle is to be operated) of the motor vehicle, for example at least 50 Kelvin, preferably at least 100 Kelvin or At least 150 Kelvin below the operating temperature of the motor vehicle (usually about -40 ° C to about + 85 ° C). The fuel may for example be hydrogen, which is stored at temperatures of about 30 K to 360 K in the cryogenic pressure vessel. The pressure vessel can be used in a motor vehicle which is operated, for example, with compressed natural gas (CNG) or liquefied natural gas (LNG). The cryogenic pressure vessel may in particular comprise an inner container which is designed for storage pressures of up to about 350 bar, preferably up to about 500 bar, and particularly preferably up to about 700 bar. The cryogenic pressure vessel preferably comprises a vacuum having an absolute pressure in the range from 10 ^-9 mbar to 10 ^-1 mbar, furthermore preferably from 10 ^-7 mbar to 10 ^-3 mbar and particularly preferably from approximately 10 ^-5 mbar. Storage at temperatures (just) above the critical point has the advantage over storage at temperatures below the critical point that the storage medium is present in a single phase. For example, there is no interface between liquid and gaseous.

The technology disclosed herein will now be explained with reference to the figures. Show it:

1 a cross-sectional view of a first embodiment of the pressure vessel system disclosed herein;

2 another cross-sectional view of the pressure vessel system 1 along the line II-II;

3 a cross-sectional view of a second embodiment of the pressure vessel system disclosed herein;

4 another cross-sectional view of the pressure vessel system 3 along the line IV-IV;

5 a cross-sectional view of a third embodiment of the pressure vessel system disclosed herein;

6 another cross-sectional view of the pressure vessel system 5 along the line VI-VI; and

7 a cross-sectional view of a fourth embodiment of the pressure vessel system disclosed herein.

1 a cross-sectional view of a first embodiment of the pressure vessel system disclosed herein. 2 shows a further cross-sectional view of the pressure vessel system 1 along the line II-II. 1 shows the view of the pressure vessel system of 2 along the line II.

1 shows only a section of the pressure vessel 10 , To the right, the pressure vessel extends 10 further. This part is in 1 Not shown. Also is in 1 only the upper half or an upper portion of the pressure vessel 10 shown. By two boundary lines is in 1 clarifies that only a section of the pressure vessel 10 is shown. The lower half or lower part of the pressure vessel 10 is in particular symmetrical to the upper part of the pressure vessel shown 10 educated.

The cryogenic pressure vessel system comprises a cryogenic pressure vessel 10 , In the pressure vessel 10 gas is stored for a fuel cell. The gas may in particular be hydrogen. The inner container 30 of the pressure vessel 10 has an outer shell 40 and an inner shell 45 on. The inner shell 45 (so-called liner) comprises or consists for example of a metal or a metal alloy, for. As aluminum. The inner shell 45 is (immediately adjacent) from the outer shell 40 surrounded, which is a composite material, eg. B. carbon fiber reinforced plastic (CFRP), comprises or consists of this. It is conceivable that more material between outer shell 40 and inner shell 45 is available. The inner container 30 encloses an interior 32 , In the interior 32 of the inner container 30 the gas is stored.

Between the outer container 20 and the inner container 30 is a partially evacuated or evacuated space 25 present, for thermal insulation between outer container 20 and inner container 30 serves.

The pressure vessel 10 saves (in the interior 32 the Innbehälters) gas, z. As hydrogen, for a fuel cell. In the interior 32 of the inner container 30 the gas is stored for the fuel cell. The fuel can be through a port 15 Port area or an inlet and outlet in the pressure vessel 10 or the inner container 30 be fed (refueling) and be led out of this again (to the fuel cell). The pressure vessel 10 in particular can be arranged or arranged in a motor vehicle. The fuel cell drives the motor vehicle.

A warming device 60 or heating device for heating the gas in the pressure vessel 10 is planned. The heating device 60 is z. B. an electric heater or electric heater. The electric heating device has two terminals (electrodes) (not shown) by means of which it is supplied with electrical energy. By ohmic losses in the material of the heating device 60 The heating device heats up 60 and thus heats the gas in the pressure vessel 10 , The electrical energy can z. B. originate from the high-voltage system of the fuel cell.

The electric heater 60 is in 1 on the outside of the inner container 30 , in particular on the outer side or outer surface of the outer shell 40 of the inner container 30 arranged. In 1 covers the heater 60 the outer shell 40 or the outer surface of the outer shell 40 of the inner container 30 completely in the circumferential direction. It is also conceivable that the heating device 60 in the circumferential direction only a portion of the outer surface of the outer shell 40 of the inner container 30 covered. In the longitudinal direction of the inner container 30 (in 1 standing vertically on the plane of the paper), the heating device 60 only a portion of the outer surface of the inner container 30 cover or completely cover the outside surface.

Instead of or in addition to an electric heating device or electric heating device, the heating device 60 comprising a heating device through which a fluid flows. The medium may be cooling water of the fuel cell or the pressure vessel 10 be removed and already heated gas. The heating device 60 can be like in 1 shown the inner container of the pressure vessel 10 enclose (in the circumferential direction) or on the outside of the inner container 30 be arranged. That by the warming device 60 flowing medium heats the gas in the pressure vessel 10 ,

It is also conceivable that the (electric or by a medium / fluid flowing through) heating device 60 helical around the inner container 30 or around the outer shell 40 of the inner container 30 is designed and arranged. Through the coil, the medium flows and heats in this way the outer shell 40 of the inner container 30 and thereby (indirectly) the gas in the pressure vessel 10 or in the interior 32 of the inner container 30 ,

It is also conceivable that around the inner container 30 an additional container is arranged, in particular the inner container 30 (almost) completely encloses. The additional container is on the outer surface of the inner container 30 or the outer surface of the outer shell 40 of the inner container 30 arranged. Through the additional container flows a medium / fluid for heating the gases in the pressure vessel.

3 shows a cross-sectional view of a second embodiment of the pressure vessel system disclosed herein. 4 shows a further cross-sectional view of the pressure vessel system 3 along the line IV-IV. 3 shows the view of the pressure vessel system of 4 along the line III-III.

3 shows only a section of the pressure vessel 10 , To the right, the pressure vessel extends 10 further. This part is in 3 Not shown. Also is in 3 only the upper half or an upper portion of the pressure vessel 10 shown. By two boundary lines is in 3 clarifies that only a section of the pressure vessel 10 is shown. The lower half or lower part of the pressure vessel 10 is in particular symmetrical to the upper part of the pressure vessel shown 10 educated.

In the 3 illustrated embodiment differs from the in 1 or in 2 illustrated embodiment in that the heating device 60 not on the outside or outer surface of the inner container 30 is arranged, but between the inner shell 45 and the outer shell 40 of the inner container 30 is arranged. The heating device 60 may be an electric heater or heating device or may be a heating device flowing through a medium.

5 shows a cross-sectional view of a third embodiment of the pressure vessel system according to the invention. 6 shows a further cross-sectional view of the pressure vessel system 5 along the line VI-VI. 5 shows the view of the pressure vessel system of 6 along the line VV.

5 shows only a section of the pressure vessel 10 , To the right, the pressure vessel extends 10 further. This part is in 5 Not shown. Also is in 5 only the upper half or an upper portion of the pressure vessel 10 shown. By two boundary lines is in 5 clarifies that only a section of the pressure vessel 10 is shown. The lower half or lower part of the pressure vessel 10 is in particular symmetrical to the upper part of the pressure vessel shown 10 educated.

In the 5 illustrated embodiment differs from the in 1 respectively. 2 illustrated embodiment in that the heating device 60 is formed by a medium / fluid permeable. The medium may be cooling water of the fuel cell or the pressure vessel 10 be removed and already heated gas.

7 shows a fourth embodiment of the pressure vessel system disclosed herein. The heating device 60 is in 7 around the liner port, ie around the part of the inner shell 45 of the inner container 30 arranged, which protrudes from the outer container. The port is the inlet and outlet for gas in and out of the inner container 30 , The heating device 60 is coupled to the pressure vessel, that is detachable from the pressure vessel, arranged.

The foregoing description of the present invention is for illustrative purposes only, and not for the purpose of limiting the invention. Various changes and modifications are possible within the scope of the invention without departing from the scope of the invention and its equivalents.

LIST OF REFERENCE NUMBERS

10

pressure vessel

20

outer container

25

evacuated room

30

inner container

32

Interior of the inner container

40

Outer shell of the inner container

45

Inner cover of the inner container

60

heater

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1546601 B1 [0002]

Claims (10)

A cryogenic pressure vessel system comprising a cryogenic pressure vessel ( 10 ), which has an inner container ( 30 ) and an outer container ( 20 ), wherein between the inner container ( 30 ) and the outer container ( 20 ) at least in regions an evacuated space ( 25 ), wherein the inner container ( 30 ) an interior ( 32 ) for storing a gas, further comprising a heating device ( 60 ) for heating the gas in the pressure vessel ( 10 ), wherein the heating device ( 60 ) outside the interior ( 32 ) of the inner container ( 30 ) is arranged. Pressure vessel system according to claim 1, wherein the heating device ( 60 ) is an electric heater. Pressure vessel system according to one of the preceding claims, wherein the inner container ( 30 ) an outer shell ( 40 ), in particular comprising a composite material, and an inner shell ( 45 wherein the heating device ( 60 ) between the inner shell ( 45 ) of the inner container ( 30 ) and the outer shell ( 40 ) of the inner container ( 30 ) is arranged. Pressure vessel system according to one of the preceding claims, wherein the inner container ( 30 ) an outer shell ( 40 ), in particular comprising a composite material, and an inner shell ( 45 ), wherein the inner shell ( 45 ) the heating device ( 60 ). Pressure vessel system according to one of the preceding claims, wherein the inner container ( 30 ) an outer shell ( 40 ), in particular comprising a composite material, and an inner shell ( 45 ), wherein the heating device ( 60 ) on the outer surface of the outer shell ( 40 ) of the inner container ( 30 ) is arranged. Pressure vessel system according to one of the preceding claims, wherein the heating device ( 60 ) is designed such that the heating device ( 60 ) of a fluid for heating the gas in the pressure vessel ( 10 ) compared to the temperature of the gas in the pressure vessel ( 10 ) has a higher temperature, can flow through. Pressure vessel system according to one of the preceding claims, wherein the heating device ( 60 ) at the inlet and outlet of the inner container ( 30 ) is detachably arranged. Pressure vessel system according to one of the preceding claims, wherein the heating device ( 60 ) the inner container ( 30 ) substantially completely encloses. Motor vehicle with a pressure vessel system according to one of claims 1-8. Method for increasing the temperature of a gas in a cryogenic pressure vessel ( 10 ), in particular in a motor vehicle, the pressure vessel having an inner container ( 30 ) and an outer container ( 20 ), wherein the inner container ( 30 ) an interior ( 32 ) for storing the gas, wherein a heating device ( 60 ) outside the interior ( 32 ) of the inner container ( 30 ) is heated to increase the temperature of the gas in the interior ( 32 ) of the inner container ( 30 ).

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