JP4729674B2 - Hydrogen storage tank and mobile body equipped with the same - Google Patents

Description

  The present invention relates to a hydrogen storage tank including a hydrogen storage body that absorbs and releases hydrogen, and a mobile body equipped with the hydrogen storage tank.

Conventionally, hydrogen storage tanks capable of storing a large amount of hydrogen in a small volume have been researched and developed in place of hydrogen cylinders. As a hydrogen storage material used for such a hydrogen storage tank, a hydrogen storage alloy has been developed, and hydrogen storage tanks using the hydrogen storage alloy have been proposed (Patent Documents 1 to 4). On the other hand, recently, as new hydrogen storage materials, alanate materials such as NaAlH ₄ and carbon materials such as carbon nanotubes have been researched and developed. In particular, lithium-based materials have recently been discovered and proposed by the inventors.
JP 2000-120996 A JP 2002-122294 A Japanese Patent Laid-Open No. 2002-221297 JP 2002-340430 A

  However, hydrogen storage alloys have a low hydrogen storage rate per unit weight, and hydrogen storage tanks using hydrogen storage alloys have not been put into practical use. In addition, new hydrogen storage materials such as lithium-based materials exhibit powder characteristics and hydrogen storage / release characteristics that are different from those of conventional storage alloys. Therefore, storage tanks using these materials must have a structure that matches those characteristics. Thus, it is not possible to secure a sufficient amount of hydrogen gas storage per unit volume. There has not been sufficient development of storage tanks using the new hydrogen storage materials as described above.

  An object of this invention is to provide the hydrogen storage tank which increases the hydrogen storage amount per unit weight or unit volume.

  In order to achieve the above object, a hydrogen storage tank according to the present invention has a hydrogen storage material whose function of storing or releasing hydrogen is activated at a temperature of 80 ° C. or higher, and storage and release of hydrogen in the hydrogen storage material. A solid hydrogen storage body including a catalyst to be promoted, a container enclosing the hydrogen storage body, a flow path forming member communicating with the outside and forming a flow path of hydrogen gas inside the container, and the hydrogen Heating means for heating the storage body to a temperature of 80 ° C. or higher.

  Thereby, when the hydrogen storage body is heated by the heating means, the function of occluding or releasing hydrogen of the hydrogen storage body is activated, so that hydrogen can be stored and released promptly. As a result, the hydrogen storage tank of the present invention can be used for a hydrogen supply device mounted on a fuel cell vehicle, a buffer tank for a stationary fuel cell, and a storage container system for a hydrogen station. It can be applied to all hydrogen storage devices in the energy society.

  Further, the hydrogen storage tank includes a lithium-based hydrogen storage material composed of lithium imide, a combination of lithium amide and lithium hydride, or a combination of lithium imide, lithium amide and lithium hydride, and hydrogen of the lithium-based hydrogen storage material. A solid hydrogen storage body including a catalyst that promotes occlusion and release, a container that encloses the hydrogen storage body, and a flow path forming member that communicates with the outside and forms a flow path for hydrogen gas inside the container. And a heating means for heating the hydrogen storage body to a temperature of 80 ° C. or higher.

  Thereby, when the hydrogen storage body is heated by the heating means, the function of occluding or releasing hydrogen of the hydrogen storage body is activated, so that hydrogen can be stored and released promptly. As a result, it is possible to provide an optimal hydrogen storage tank for a lithium-based material. Further, since the lithium-based material has a larger amount of hydrogen storage per unit weight than a hydrogen storage alloy or the like, the amount of hydrogen stored per mass of the tank can be increased. As a result, the hydrogen storage tank of the present invention can be used for a hydrogen supply device mounted on a fuel cell vehicle, a buffer tank for a stationary fuel cell, and a storage container system for a hydrogen station. It can be applied to all hydrogen storage devices in the energy society.

  In the hydrogen storage tank, the heating means includes a heat medium having a boiling point of 100 ° C. or higher, a circulation pipe that forms a circulation path between the outside and the inside of the container, and a heater that heats the heat medium. And a circulation pump that pumps the heat medium in the circulation pipe. Thereby, a hydrogen storage body can be heated efficiently and hydrogen can be occluded and released in a short time.

  In the hydrogen storage tank, it is preferable that the internal flow path forming member is a spiral gas flow pipe having a porous pipe wall that transmits hydrogen gas. Thereby, the surface area of a gas distribution pipe can be enlarged and the efficiency with which a hydrogen storage body occludes or discharges hydrogen can be increased.

  In addition, it is preferable that the mobile body is equipped with the hydrogen storage tank. Thereby, it is possible to realize a fuel cell vehicle or a hydrogen engine vehicle that is light and has a long traveling distance that can be driven by one replenishment.

  According to the hydrogen storage tank of the present invention, when the hydrogen storage body is heated by the heating means, the function of occluding or releasing hydrogen in the hydrogen storage body is activated. Can be done.

  As a result, it is possible to provide a hydrogen storage tank that is particularly suitable for lithium-based materials. Further, since the lithium-based material has a larger amount of hydrogen storage per unit weight than a hydrogen storage alloy or the like, the amount of hydrogen stored per mass of the tank can be increased. As a result, the hydrogen storage tank of the present invention can be used for a hydrogen supply device mounted in a storage fuel cell vehicle, a buffer tank for a stationary fuel cell, and a storage container system for a hydrogen station, which is expected in the future. It can be applied to all hydrogen storage devices in the hydrogen energy society.

  Further, according to the hydrogen storage tank of the present invention, the hydrogen storage body can be efficiently heated, and hydrogen can be occluded and released in a short time.

  Further, according to the hydrogen storage tank according to the present invention, the surface area of the gas flow pipe can be increased, and the efficiency with which the hydrogen storage body absorbs or releases hydrogen can be increased.

  Further, according to the moving body according to the present invention, it is possible to realize a fuel cell vehicle or a hydrogen engine vehicle that is light and has a long traveling distance that can be driven by one replenishment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in order to facilitate understanding of the description, the same reference numerals are given to the same components in the respective drawings, and duplicate descriptions are omitted.

[Embodiment 1]
FIG. 1 is a cross-sectional view of a hydrogen storage tank according to the present invention. As shown in FIG. 1, the hydrogen storage tank 1 includes a hydrogen storage body 2, a container 3, an internal circulation pipe 4, a safety valve 5, a heater 6, an external circulation pipe 7, and a filter 8. As main materials of the hydrogen storage body 2, lithium amide (LiNH ₂ ) and lithium hydride (LiH), or lithium imide (Li ₂ NH) are used. As materials, materials other than lithium-based storage materials may be used as long as the function of occluding or releasing hydrogen at 80 ° C. or higher is activated. For example, non-lithium metal amides and metal amide compounds, metal hydrides, alanate materials such as NaAlH ₄ , and carbon materials such as carbon nanotubes may be used.

  Furthermore, the hydrogen storage body 2 includes a catalyst component that promotes the storage and release of hydrogen. Catalyst components include B, C, Mn, Fe, Co, Ni, Pt, Pd, Rh, Li, B, Na, Mg, K, In, Nd, La, Ca, V, Ti, Cr, Cu, Zn One, or two or more compounds selected from Al, Si, Ru, Mo, W, Ta, Zr, Hf and Ag. The solid composed of the lithium-based storage material and the catalyst component is the hydrogen storage body 2. The hydrogen storage body 2 is formed as a powder, a granule, or a molded body, for example. As a method for producing the hydrogen storage body 2, a method in which an appropriate amount of lithium amide and lithium hydride are mixed, mechanochemically mixed and ground by milling in an atmosphere of hydrogen gas or an inert gas, and an appropriate amount of catalyst material is added is preferable. However, it is not necessarily limited to this method.

  The container 3 accommodates the hydrogen storage body 2 and has an airtight structure except for an opening through which hydrogen gas is circulated. For the container 3, for example, a material and a shape capable of withstanding a pressure of up to 10 MPa are selected. There is no particular limitation as long as the material and shape can withstand a pressure of about several MPa when hydrogen is stored in the hydrogen storage body 2. Thereby, even if it is a case where the pressure rise by rapid discharge | release is accompanied at the time of hydrogen discharge | release, it is sufficient as intensity | strength of a container and can maintain safety | security. As shown in FIG. 1, the container 3 has a cylindrical shape with rounded edges. For example, when it is mounted on an automobile, it may have a shape matched to the rear seat in order to eliminate useless space. Furthermore, a safety valve 5 set to open at a constant pressure of less than 10 MPa is installed in the container. Such a safety valve 5 may be provided if necessary, but may not be provided. The container 3 may be provided with an entrance / exit mechanism such as an openable / closable entrance / exit through which the hydrogen storage body 2 can be taken in / out. In that case, it is good also as a mechanism in which the hydrogen storage body 2 can be taken in / out by the cartridge type.

  The internal flow pipe 4 as a flow path forming member forms a flow path for sending hydrogen to the hydrogen storage body 2 and releasing the hydrogen released from the hydrogen storage body 2 to the outside of the container 3. The flow path forming member is a member that forms a flow path of hydrogen gas for occlusion or release. The internal flow pipe 4 is a flow pipe configured in a cylindrical shape by a porous pipe wall that allows hydrogen gas to pass through. One end of the pipe communicates with the outside of the container through the opening of the container 3 and the other end is closed. ing. Thus, the internal flow pipe 4 is inserted through the hydrogen storage body 2. Since hydrogen gas permeate | transmits uniformly from the whole pipe wall of the internal flow pipe 4 penetrated, hydrogen gas can be occluded or discharged | emitted efficiently.

  The heater 6 as a heating means is an electrothermal heater provided outside the container 3. The heating means refers to means for heating the hydrogen storage body 2 to a temperature of 80 ° C. or higher directly or indirectly via the container 3. The heater 6 has a function capable of being heated to a temperature of 80 ° C. or higher, and is preferably capable of being heated to 250 ° C.

  Since the heater 6 is provided in this way, when the hydrogen storage body 2 is heated by the heater 6, the function of occluding or releasing hydrogen of the hydrogen storage body 2 is activated, so that the hydrogen Occlusion and release can be performed. As a result, it is possible to provide the hydrogen storage tank 1 that is optimal for lithium-based materials. Further, since the lithium-based material has a larger amount of hydrogen storage per unit weight than a hydrogen storage alloy or the like, the amount of hydrogen stored per mass of the tank can be increased. As a result, the hydrogen storage tank 1 can be used for a hydrogen supply device mounted on a fuel cell vehicle, a buffer tank for a stationary fuel cell, and a storage container system for a hydrogen station. It can be applied to all hydrogen storage devices.

  Thus, when a material mainly composed of a lithium-based storage material is used as the hydrogen storage body 2, it is preferable to adjust the temperature to 100 to 250 ° C. in order to efficiently store and release hydrogen. is there. By heating the hydrogen storage body 2, the occlusion treatment can be performed in a very short time not only during the release but also during the occlusion. A power source (not shown) is connected to the heater 6. The power supply is also provided with a control system (not shown) that feeds back the hydrogen release amount. Thereby, the hydrogen release amount can be controlled.

  The external flow pipe 7 as a flow path forming member is configured by a pipe wall that does not allow hydrogen gas to pass therethrough. A filter 8 having a function in which reactive gases other than hydrogen such as oxygen and water vapor cannot enter is provided inside the external flow pipe 7. Thereby, it can prevent that a hydrogen storage body reacts with oxygen, water vapor | steam, etc., and deteriorates, and the occlusion performance can be maintained. Such a filter 8 may be provided if necessary, but may not be provided. The material of the filter 8 is preferably a hydrogen permeable material such as a palladium alloy (Au: 5%, Ag: 20%, Pd: 70%). The filter 8 may be provided inside the internal circulation pipe 4. Further, instead of the filter 8, a hydrogen permeable substance film may be provided on the inner or outer surface of the internal flow pipe 4, or a hydrogen permeable substance may be used as the material of the tube wall of the internal flow pipe 4.

Next, the operation of the hydrogen storage tank 1 will be described. When hydrogen gas is stored in the hydrogen storage tank 1, the hydrogen storage body 2 is first heated by the heater 6 and maintained at a temperature at which the hydrogen storage function is fully exhibited, for example, 120 ° C. Hydrogen gas is pumped at a pressure of about 10 MPa by a compressor (not shown) connected to the external flow pipe 7 and occluded in the hydrogen storage body 2 through the internal flow pipe 4. During the occlusion, a reaction of Li ₂ NH + H ₂ → LiNH ₂ + LiH occurs in the hydrogen storage body 2. On the other hand, when hydrogen gas is released from the hydrogen storage tank 1, the hydrogen storage body 2 is first heated by the heater 6 and maintained at a temperature at which the hydrogen releasing function is fully exhibited, for example, 200 ° C. Hydrogen gas is released from the hydrogen storage body 2 by heating, and the hydrogen gas is sent to the external flow pipe 7 through the internal flow pipe 4. At the time of discharge, a reaction of LiNH ₂ + LiH → Li ₂ NH + H ₂ occurs in the hydrogen storage body 2.

[Embodiment 2]
In the first embodiment, the heater 6 is provided outside the container 3 as a heating unit. However, as shown in FIG. 2, the heater 10 may be provided inside the container 3. The heater 10 is an electrothermal heater, and the function is the same as that of the heater 6 of the first embodiment. Thus, by providing the heater 10 inside, it becomes easy to control the temperature of the hydrogen storage body 2, and the efficiency of occlusion and discharge | release of hydrogen can be raised. The heater 10 may be provided with heat transfer fins around it in order to improve thermal conductivity.

  In this case as well, a power source (not shown) is connected to the heater 10. Due to the necessity of controlling the hydrogen release amount, the power supply is provided with a control system (not shown) in which the hydrogen release amount is fed back.

[Embodiment 3]
In the first embodiment, the heater 6 is provided outside the container 3 as a heating unit. However, as shown in FIG. 3, a heating medium (not shown) having a boiling point of at least 100 ° C. A circulation pipe 20 that forms a circulation path of the heat medium between the inside and the inside, a heater 21 that heats the heat medium, and a circulation pump 22 that pumps the heat medium into the circulation pipe 20 may be provided. The heater 21 is an electrothermal heater, and a power source (not shown) is connected to the heater 21 as an external system. Due to the necessity of controlling the hydrogen release amount, the power supply is provided with a control system (not shown) that feeds back the hydrogen release amount. Thereby, the hydrogen storage body 2 can be heated efficiently, and hydrogen can be occluded and released in a short time. When this heating means is used, the temperature of the heat medium is kept below the boiling point. The circulation pipe 20 may be provided with heat transfer fins around it in order to improve thermal conductivity.

[Embodiment 4]
In the first embodiment, the cylindrical internal flow pipe 4 is provided as the flow path forming member. However, as shown in FIG. 4, the internal flow pipe 30 may be provided as a spiral gas flow pipe. . Thereby, the surface area of the internal flow pipe 30 can be increased, and the efficiency with which the hydrogen storage body occludes or releases hydrogen can be increased.

[Embodiment 5]
Further, as shown in FIG. 5, the hydrogen storage tank 41 may be mounted on a fuel cell vehicle as a moving body. As a result, it is possible to realize a fuel cell vehicle that is light and has a long mileage that can be driven by one replenishment. In the hydrogen storage tank 41, the external flow pipe 47 is branched into an external flow pipe 47a for storing hydrogen gas and an external flow pipe 47b for releasing hydrogen gas. The external circulation pipe 47a for storing hydrogen gas and the external circulation pipe 47b for releasing hydrogen gas are provided with a lid or a valve that can close the pipe. The external circulation pipe 47 b for releasing hydrogen gas is formed so as to straddle over the rear shaft 51 connected to the rear tire 50, and is connected to the fuel cell 60. Since the temperature of the hydrogen storage tank 41 increases, it is preferable to cover the periphery with a heat insulating material. On the other hand, on the opposite side of the vehicle body from the hydrogen storage tank 41, an oxygen suction pipe 61 is connected to the compressor 62. A pressure feeding pipe 63 is connected to the fuel cell 60 on the opposite side of the compressor 62 from the oxygen suction pipe 61. Further, the fuel cell 60 is provided with a water discharge pipe 64.

  The fuel cell 60 is connected to a conducting wire 70 that conducts the generated power, and the other end of the conducting wire 70 is connected to a battery 71. A conductive wire 72 is connected to the battery 71, and the other end is connected to the motor 80. A front shaft 82 that transmits the power of the motor 80 to the front tire 81 is rotatably attached to the motor 80. In FIG. 5, for the sake of simplicity, the front shaft 82 is expressed as being directly attached to the motor 80, but actually the power of the motor 80 is applied to the front tire using a pulley or a clutch mechanism. Transmit power.

  In addition, when providing the entrance / exit mechanism which can take in / out the hydrogen storage body 2 in the container 43 of the hydrogen storage tank 41, it is good also as a mechanism which can be taken in / out with the hydrogen storage tank 41 mounted in the motor vehicle 40, or hydrogen storage. It is good also as a mechanism which removes the tank 41 and takes in / out at another place. In addition, the mobile body on which the hydrogen storage tank is mounted is not limited to a fuel cell vehicle, and may be a hydrogen engine vehicle. Examples of the mobile body include vehicles such as automobiles and motorcycles, ships, and airplanes.

  Next, the operation of the automobile 40 will be described. First, when hydrogen gas is replenished to the automobile 40, the hydrogen storage tank 41 is heated to an optimum temperature at a hydrogen station or the like where a hydrogen replenishment system is provided, and externally in the direction of arrow A shown in FIG. Hydrogen gas is pumped from the flow pipe 47a. At this time, the external circulation pipe 47b is closed. In this way, the hydrogen gas is stored in the hydrogen storage body in the hydrogen storage tank 41.

  When driving the automobile 40, first, with the external circulation pipe 47a closed, the internal hydrogen storage body is heated to an optimum temperature by the heating means of the hydrogen storage tank 41, and hydrogen gas is sent into the external circulation pipe 47b. . On the other hand, the compressor 62 is started, oxygen (air) is sent from the oxygen suction pipe 61 to the fuel cell 60 through the pressure feed pipe 63 in the direction of arrow B shown in FIG. . At this time, water generated by the reaction is discharged from the water discharge pipe 64 to the outside. The motor 80 is driven by the electric power stored in the battery 71 to rotate the front shaft 82 and the front tire 81. In this way, the automobile 40 is driven. In addition, these embodiment is an illustration, Comprising: This invention is not limited to these embodiment.

It is sectional drawing which shows 1st Embodiment of the hydrogen storage tank which concerns on this invention. It is sectional drawing which shows 2nd Embodiment of the hydrogen storage tank which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the hydrogen storage tank which concerns on this invention. It is sectional drawing which shows 4th Embodiment of the hydrogen storage tank which concerns on this invention. It is the schematic which shows an example of the moving body which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydrogen storage tank 2 Hydrogen storage body 3 Container 4 Internal distribution pipe (flow-path formation member)
5 Safety valve 6 Heater (heating means)
7 External distribution pipe (channel forming member)
8 Filter 10 Heater (heating means)
20 Circulating pipe 21 Heater 22 Circulating pump 30 Internal flow pipe (flow path forming member)
40 automobile (mobile)
41 Hydrogen storage tank 43 Container 47a External flow pipe (flow path forming member)
47b External flow pipe (flow path forming member)

Claims (4)

Lithium imide, a combination of lithium amide and lithium hydride, or a lithium-based hydrogen storage material comprising a combination of lithium imide, lithium amide and lithium hydride, and a catalyst for promoting the storage and release of hydrogen in the lithium-based hydrogen storage material A solid hydrogen storage body comprising:
A container for enclosing the hydrogen storage body;
A flow path forming member that communicates with the outside and forms a flow path of hydrogen gas inside the container;
A hydrogen storage tank, comprising: a heating unit that heats the hydrogen storage body to a temperature of 80 ° C. or higher. The heating means includes
A heating medium having a boiling point of 100 ° C. or higher;
A circulation pipe forming a circulation path between the outside and the inside of the container;
A heater for heating the heat medium;
The hydrogen storage tank according to claim 1, further comprising: a circulation pump that pumps the heat medium in the circulation pipe. The internal flow path forming member has a spiral gas flow having a porous tube wall that is permeable to hydrogen gas.
The hydrogen storage tank according to claim 1, wherein the hydrogen storage tank is a through pipe. The mobile body carrying the hydrogen storage tank as described in any one of Claims 1-3.

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