JP2002237318A - Hydrogen storage material and hydrogen storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-performance hydrogen storage material which is light-weight and superior in durability, which is easy to handle and enhanced in safety and further which has a simple structure and can form an inexpensive hydrogen storage device. SOLUTION: This is the hydrogen storage material having a capsule 1 to permeate only hydrogen, fullerene 2 such as C60 or the like enclosed in the capsule 1, or a nano-tube. The capsule is preferably to be equipped with the capsule main body 11 wherein a plurality of micropores 1a are formed on a shell wall and with a hydrogen permeating membrane 12 constituted so that the outer face of the capsule body is covered and that only hydrogen is to be permeated. This is the hydrogen storage device constituted by using the hydrogen storage material, and comprised to have an air-tight container installed with hydrogen supply/drain ports, the plurality of hydrogen storage materials housed in this container, and a heating device for heating this hydrogen storage material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for storing hydrogen used as fuel in a fuel cell, for example.

[0002]

At present, research and development of a clean power source for a vehicle, which replaces an internal combustion engine that obtains power by burning fossil fuel, is being conducted. In particular, expectations for an electric drive system using a fuel cell as a generator are extremely high.

Needless to say, there are various types of fuel cells, and at present, the type in which hydrogen and oxygen react with each other is mainly used. However,
There are still problems that need to be resolved. That is how to supply hydrogen as fuel to the fuel cell.

[0004] In general, the following three systems can be considered for the supply (storage) of hydrogen. The first is a method using a hydrogen storage alloy, the second is a liquefied or gaseous state and stored in a tank at high pressure, and the third is a method of producing directly from methanol using a reformer. It is. But
Both systems have drawbacks.

First, when a hydrogen storage alloy is used, the weight of the device becomes very large because it is incorporated into the device as a large metal lump. Further, the hydrogen storage alloy is pulverized at an early stage, and thus has low durability. On the other hand, the tank storage method is difficult to handle and inferior in safety. The method using a reformer requires a large-scale and complicated apparatus and is very expensive.

Accordingly, an object of the present invention is to provide an inexpensive hydrogen storage device that is lightweight, has excellent durability, is easy to handle, has high safety, and has a simple structure. It is to be. In particular, it is an object of the present invention to provide a high-performance hydrogen storage device capable of forming such a hydrogen storage device.

[0007]

This problem is solved by a hydrogen absorbing body comprising a capsule that allows only hydrogen to pass therethrough, and a fullerene sealed in the capsule. Here, C ₆₀ can be mentioned as a particularly preferred fullerene.

[0008] The above-mentioned object is attained by a hydrogen storage body comprising a capsule that allows only hydrogen to pass therethrough, and a nanotube enclosed in the capsule.

The capsule includes a capsule body having a plurality of pores formed in a shell wall, and a hydrogen permeable membrane provided to cover the outer surface of the capsule body and allowing only hydrogen to pass therethrough. Can be mentioned. Capsules of this construction are very easy to manufacture and, in addition, exhibit particularly good performance.

[0010] On the contrary, an object to be solved is a hydrogen storage device constituted by using the above-mentioned hydrogen storage body.
An airtight container provided with a discharge port, a plurality of the hydrogen storage units housed in the container, and a heating unit for heating the hydrogen storage units are provided. Solved by a hydrogen storage device.

[0011] Now, in the above hydrogen storage material according to the present invention,
Hydrogen (Hydrogen molecule) penetrating the shell wall and entering the capsule
Is physically held by the fullerene encapsulated inside the capsule. That is, the inside of the fullerene is in a complete vacuum, so the hydrogen that has entered the capsule is
Immediately, it enters the fullerene interior (vacuum space) and is trapped therein. That is, hydrogen is occluded in the fullerene in the capsule, and as a result, it is in a state of being stably stored by the hydrogen occlusion body (by the way, hydrogen is released by heating the hydrogen occlusion body to a certain temperature).

By the way, as described above, the hydrogen storage body of the present invention is made by encapsulating carbon fine powder in a capsule, so that it is much lighter than a metal lump, and compared to the case where a hydrogen storage alloy is used. , Significantly reducing the weight. Moreover, since the hydrogen storage body of the present invention does not become fine powder unlike a hydrogen storage alloy, it can be used repeatedly over a long period of time. That is, the hydrogen storage body of the present invention is extremely excellent in durability. In addition, the hydrogen storage body of the present invention is easy to handle because it does not contain hydrogen by liquefying or compressing it as a gas at high pressure, and is excellent in safety. Furthermore, the hydrogen storage body of the present invention can be provided at low cost because the structure is very simple.

Therefore, the hydrogen storage device of the present invention formed using this high-performance and high-performance hydrogen storage body is lightweight,
In addition, it has excellent durability, is easy to handle, has high safety, and has a simple structure and is inexpensive. The same applies to the case where nanotubes are used instead of fullerenes.

Although the shape of the capsule is not particularly limited, examples thereof include a perfect true sphere, a somewhat whisker-like sphere, a shape like a rugby ball obtained by stretching a sphere in one direction (spheroid), and a spheroid. May have a columnar shape. However, space efficiency and surface utilization efficiency when filling the hydrogen storage body densely in the container,
Further, considering the strength and the like, it is most desirable that the capsule be a true sphere.

Here, for reference, the fullerene, especially C
₆₀ will be briefly described. C _{6 0} is Generally speaking, a total of 60 carbon atoms, a truncated twenty faces form which can cut off the vertices of the regular icosahedron, and has a structure bonded to a soccer ball shape other words. Besides _{C 60} to fullerene, for example, _{C 70} and _{C 76, C 78, C 8}
There are things like ₂ . However, overall it is determined, as the fullerene, also C ₆₀ is most desirable. On the other hand, the nanotube has a structure in which carbon atoms are bonded in a long tubular shape, and thus has a much higher molecular weight than that of fullerene.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be specifically described below with reference to FIGS. FIG. 1 is a half cross-sectional view of the hydrogen storage body according to the present embodiment, and FIG. 2 is a schematic cross-sectional view of the hydrogen storage device according to the present embodiment.

The hydrogen storage unit according to the present embodiment (hereinafter referred to as the present hydrogen storage unit) also constitutes the hydrogen storage device according to the present embodiment (hereinafter referred to as the present hydrogen storage unit or the present device). is there. That is, the main part of the present device is formed from countless present hydrogen storage bodies. The present device described below is intended for storing (storing) hydrogen used as fuel in a vehicle fuel cell. In other words, the device serves as a hydrogen supply.

As can be seen from FIG. 1, the present hydrogen storage material comprises a spherical capsule 1 that allows only hydrogen to pass therethrough, and a fullerene encapsulated in the capsule 1 (more precisely, a certain amount of fine powder made of fullerene). 2) as main components. However, here, fullerene 2 is C
₆₀ was used. The occupancy rate (apparent occupancy rate) of the fullerene 2 in the capsule interior space is about 80%.

The capsule 1 has a two-layer structure. More specifically, the capsule 1 has an infinite number of pores (through holes) 1 in the shell wall.
The capsule body 11 is formed of a capsule body 11 having a diameter (outer diameter) of about several mm and a hydrogen permeable membrane 12 provided so as to cover the outer surface of the capsule body 11. The former is mainly composed of quartz glass, and the pores 1a are formed by using, for example, a known and commonly used photo-etching process.

On the other hand, the latter, that is, the hydrogen permeable membrane 12 plays a role of transmitting only hydrogen (hydrogen molecules).
Its thickness is about 1 to several μm. In this embodiment,
The hydrogen permeable film 12 was formed using a material such as palladium alone by a technique such as vacuum evaporation or plating. But,
Instead of palladium alone, a palladium / silver / gold based alloy or a lanthanum / nickel based alloy may be used as the material of the hydrogen permeable film 12.

By providing this hydrogen permeable membrane 12, gas other than hydrogen, for example, oxygen, does not enter the capsule body 11. Therefore, oxidation of the fullerene 2 and, hence, a decrease in its hydrogen storage capacity are effectively suppressed. Incidentally, in the production of the present hydrogen storage material, a method was used in which an appropriate amount of fullerene was injected into the capsule base material having an opening from the opening and then heated to close the opening. However, all the steps of the manufacturing operation of the present hydrogen storage body are performed in a hydrogen atmosphere. This is to prevent unnecessary gas such as oxygen from entering the capsule 1.

Next, a description will be given of a hydrogen storage device according to the present embodiment formed using the present hydrogen storage body having the above structure. As can be seen from FIG. 2, the present apparatus comprises a rigid metal container 31 having airtightness, the myriad (for example, tens of thousands to several millions) of the above-mentioned hydrogen storage bodies 32 housed therein, An electric heater (heating means) 33 for heating the occlusion body 32 is provided as a main component.

The container 31 among the above components is
A hydrogen supply port 31a and a hydrogen discharge port 31b are provided. Filters (not shown) are arranged in these openings, so that the hydrogen storage bodies 32 in the container 31 do not jump out. Note that the hydrogen supply port 31a and the hydrogen discharge port 31b may be integrated into one, and may be switched by a valve.

In order to occlude hydrogen using the present apparatus, the hydrogen occlusion body 32 is heated to a predetermined temperature using the heater 33, and in this state, the hydrogen occlusion body 31 is slightly inserted into the container 31 through the hydrogen supply port 31a. The hydrogen may be filled by applying pressure (at this time, the hydrogen discharge port 31b is closed). Then, the hydrogen that has flowed into the container 31 is immediately stored in the hydrogen storage body 32 by the fullerene constituting the hydrogen storage body 32, and as a result, is safely and reliably stored.

On the other hand, when releasing the stored hydrogen, the heater 33 is operated and the hydrogen storage body 32 is released.
Is raised by about 200 ° C. from the temperature at the time of occlusion (at this time, the hydrogen supply port 31a is closed). Then
The hydrogen trapped inside the fullerene quickly jumps out, further passes through the capsule shell wall and the hydrogen permeable membrane, and is finally discharged out of the container 31 from the hydrogen discharge port 31b.

As described above, in the present hydrogen storage body, the hydrogen that has penetrated the shell wall and entered the capsule is physically held by the fullerene sealed inside the capsule. That is, since the inside of the fullerene is in a complete vacuum, hydrogen that has entered the capsule immediately enters the inside of the fullerene, and is trapped therein. That is, hydrogen is stored in fullerene in the capsule, and as a result, hydrogen is stably stored by the hydrogen storage.

On the other hand, the present hydrogen storage material is much lighter than a metal lump because it contains a fine powder of fullerene in a capsule as described above. And significantly lighter. Moreover, unlike a hydrogen storage alloy, it does not become finely divided, has excellent durability, and can be used repeatedly over a long period of time.

Further, since hydrogen is not liquefied or compressed as it is at a high pressure as a gas, it is easy to handle and excellent in safety. Further, the present hydrogen storage body has a very simple structure, so that the manufacturing cost is low. Therefore, this hydrogen storage device using this high-performance and high-performance hydrogen storage body is also lightweight, has excellent durability, is easy to handle, has high safety, and has a simple structure. , Can be provided at low cost.

In this embodiment, the structure and function of the present apparatus have been described by taking as an example a case where the apparatus is used as a hydrogen supply source to a fuel cell. However, it goes without saying that the application of the hydrogen storage device according to the present invention is not limited to such a case. Further, as another embodiment of the hydrogen storage material according to the present invention, a structure having a capsule that allows only hydrogen to pass therethrough and a nanotube sealed in the capsule can be mentioned.

[0030]

According to the present invention, it is possible to provide an inexpensive hydrogen storage device which is lightweight, has excellent durability, is easy to handle, has high safety, and has a simple structure. In particular, a high-performance hydrogen storage body capable of forming such a hydrogen storage device is obtained.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a hydrogen storage body according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a hydrogen storage device according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 capsule 1a pore (through hole) 2 fullerene 11 capsule main body 12 hydrogen permeable membrane 31 container 31a hydrogen supply port 31b hydrogen discharge port 32 hydrogen storage body 33 heater (heating means)

Claims (5)

[Claims] 1. A hydrogen storage body comprising: a capsule that allows only hydrogen to pass therethrough; and a fullerene encapsulated in the capsule. 2. A hydrogen absorbing material according to claim 1, fullerene characterized in that it is a C _60. 3. A hydrogen storage body comprising: a capsule that allows only hydrogen to pass therethrough; and a nanotube sealed in the capsule. 4. A capsule comprising: a capsule body having a plurality of pores formed in a shell wall; and a hydrogen permeable membrane provided to cover an outer surface of the capsule body and permeable only to hydrogen. Claim 1 characterized by the above-mentioned.
The hydrogen storage material according to claim 3. 5. A hydrogen storage device comprising the hydrogen storage body according to any one of claims 1 to 4, wherein the hydrogen storage device has an airtight container provided with a hydrogen supply / discharge port. A hydrogen storage device comprising: a plurality of the hydrogen storage units housed in the container; and heating means for heating the hydrogen storage units.