JP5061529B2 - High pressure hydrogen storage container - Google Patents

Description

  The present invention relates to an improvement of a high-pressure hydrogen storage container, particularly a high-pressure hydrogen storage container equipped with a hydrogen storage material or a hydrogen adsorption material.

  As an example of a fuel cell system to which a high-pressure hydrogen storage container equipped with a conventional hydrogen storage material or the like is applied, there is a technique described in Patent Document 1.

  This technology is a system including a starting high-pressure hydrogen storage container containing a low-temperature hydrogen storage alloy and an operating high-pressure hydrogen storage container containing a high-temperature hydrogen storage alloy. In this system, the high-pressure hydrogen storage container for supplying hydrogen is switched according to the operating conditions, and the start-up high-pressure hydrogen storage container can be filled with hydrogen using hydrogen from the high-pressure hydrogen storage container for operation. This prevents the supply of hydrogen from being stopped when the container is emptied.

Usually, a fuel cell system equipped with a high-pressure hydrogen storage container is equipped with a heat exchange device for dissipating heat generated by the storage of hydrogen in the high-pressure hydrogen storage container. The heat dissipation performance is set according to the heat generation amount of the container. That is, a heat release amount corresponding to the maximum heat generation amount per unit time of the high-pressure hydrogen storage container is set.
JP 2001-302201 A

  However, the heat dissipation performance of the heat exchange device provided for heat dissipation of the high-pressure hydrogen storage container is set according to the maximum heat dissipation amount per unit time of the high-pressure hydrogen storage container. There is a problem that it increases, resulting in a decrease in the amount of hydrogen that can be stored or a decrease in living space.

  Accordingly, an object of the present invention is to provide a high-pressure hydrogen storage container capable of reducing the maximum heat radiation amount per unit time and reducing the size of the heat exchange device.

The present invention relates to a high-pressure hydrogen storage container comprising a hydrogen container filled with a material that absorbs or adsorbs hydrogen and a liner that houses the hydrogen container, and a refrigerant that cools the material flows in the hydrogen container. refrigerant pipe is provided to, said material is different with the plateau pressure, hydrogen consists absorbing or adsorbing properties are different materials, wherein the plurality of materials are mixed is filled in the hydrogen container, said plurality The difference in plateau pressure between the materials is equal .

  In the present invention, the hydrogen container is filled with a plurality of materials having the characteristics of occluding or adsorbing different hydrogen, so the timing of the maximum calorific value of each material associated with the occlusion or adsorption of hydrogen is shifted and the maximum release per unit time. The amount of heat can be reduced. For this reason, the required performance of the pipe | tube diameter and plate | board thickness of the refrigerant | coolant piping for the thermal radiation of the said material, the pump for circulating a refrigerant | coolant, etc. can be reduced, and weight reduction and cost reduction can be achieved.

  FIG. 1 is a configuration diagram of a fuel cell system to which a high-pressure hydrogen storage container of the present invention is applied. In the drawing, a portion surrounded by a one-dot chain line indicates a heat exchange system unit for releasing heat of the hydrogen storage alloy X.

  Reference numeral 1 denotes a high-pressure hydrogen storage container containing a hydrogen storage alloy X that stores and releases hydrogen, and reference numeral 10 denotes a hydrogen supply source that fills the high-pressure hydrogen storage container 1 with hydrogen via a hydrogen pipe 11.

  The solid line arrows shown in the heat exchange system section indicate the flow of the refrigerant, the hydrogen storage alloy X is cooled, and the heated refrigerant is sent from the high-pressure hydrogen storage container 1 to the radiator 13 through the first refrigerant pipe 12. Cooled down. The cooled refrigerant is sent to the fuel cell stack 14 through the second refrigerant pipe 15 for heat dissipation of the fuel cell stack 14. When the temperature of the refrigerant sent from the high-pressure hydrogen storage container 1 is lower than a predetermined temperature, a first bypass pipe 16 that bypasses the radiator 13 connects the first refrigerant pipe 12 and the second refrigerant pipe 15. The first three-way valve 17 that controls the flow of the refrigerant is installed at the junction between the first bypass pipe 16 and the second refrigerant pipe 15. A pump 21 driven by a motor 22 is installed in the second refrigerant pipe 15.

  The refrigerant that has cooled the fuel cell stack 14 is sent to the high-pressure hydrogen storage container 1 through the third refrigerant pipe 18 and is used for heat dissipation of the high-pressure hydrogen storage container 1. Here, the second bypass pipe 19 that bypasses the fuel cell stack 14 is provided between the second refrigerant pipe 15 and the third refrigerant pipe 18, and the temperature of the refrigerant supplied to the fuel cell stack 14 does not reach a predetermined temperature. In this case, the refrigerant is sent to the high-pressure hydrogen storage container 1 without being sent to the fuel cell stack 14. A second three-way valve 20 that controls the flow of the refrigerant to the second bypass pipe 19 is provided at the junction of the second refrigerant pipe 15 and the second bypass pipe 19.

  A controller 23 for integrated control of the fuel cell system is installed. The controller 23 outputs an output signal of a temperature sensor 24 that detects the temperature of the refrigerant discharged from the radiator 13 and the refrigerant flowing into and out of the fuel cell stack 14. The output signals of the temperature sensors 25 and 26 for detecting the temperature and the output signal of the temperature sensor 27 for detecting the temperature of the high-pressure hydrogen storage container 1 are read, and based on the detected temperatures, the first and second three-way valves 17, 20, The motor 22, the valve units 4a and 4b of the high-pressure hydrogen storage container 1 described later, and the hydrogen supply source 10 are controlled.

  FIG. 2 is a configuration diagram of the high-pressure hydrogen storage container 1.

  The high-pressure hydrogen storage container 1 which is a pressure-resistant container that can withstand high pressure (for example, 35 MPa) includes a liner 2, a reinforcing member 3 that reinforces the liner 2, hydrogen in the high-pressure hydrogen storage container 1, and cooling of the hydrogen storage alloy X. For this reason, it is composed of a pair of valve units 4a and 4b for controlling the flow of refrigerant in and out, and a hydrogen storage alloy container 5 in which the hydrogen storage alloy X is housed.

  The liner 2 is formed in a cylindrical main body 2a, a substantially hemispherical dome 2b, 2c that closes the open end of the main body 2a, and the dome 2b, 2c. It consists of a boss 2e having a through hole 2d communicating with the outside.

  The reinforcing member 3 is wound around the outer peripheral surface of the liner 2 and is formed of, for example, fiber reinforced plastic (FRP). Since the liner 2 is reinforced by the reinforcing member 3, the weight can be reduced while securing the strength.

  The valve units 4a and 4b are attached to the through holes 2d formed in the boss portions 2e of the dome portions 2a and 2b, and are controlled by the controller 23 to adjust the inflow and outflow amounts of hydrogen and refrigerant into the high-pressure hydrogen storage container 1. To do.

  As shown in FIG. 2, the hydrogen storage alloy container 5 is a covered cylindrical container filled with the hydrogen storage alloy X, and includes a cylindrical main body portion 5a, a flat lid portion 5b that closes both ends of the opening, It consists of a support bar 5c that connects the lids 5b at the center of the container. In the hydrogen storage alloy container 5, a refrigerant pipe 6 through which a refrigerant for cooling the hydrogen storage alloy X flows is provided. The refrigerant pipe 6 includes a collecting portion 6a formed in each lid portion 5b and a lid portion 5b. It consists of a plurality of refrigerant pipes 6b that connect the collecting portion 6a in the central axis direction, and an inlet pipe 6c that connects the collecting portion 6a of one lid portion 5b and one valve unit 4b. Further, a through hole 6d that penetrates the inside of the support bar 5c and communicates with the other collecting portion 6a is provided, and the refrigerant pipe 6 has an outlet that communicates the through hole 6d, the through hole 6d, and the one valve unit 4b. It is formed from the pipe 6e.

  The refrigerant pipe 6 configured as described above is configured such that the refrigerant is supplied from the valve unit 4b, absorbs the heat of the hydrogen storage alloy X, and then is discharged from the valve unit 4b. In addition, thin fins with excellent thermal conductivity are arranged in the direction perpendicular to the axis, and the fins are fixed to the support rods 5c and the refrigerant pipes 6b, and the hydrogen storage alloy contacts the fins to promote heat exchange, thereby improving efficiency. You may comprise so that the heat | fever of the hydrogen storage alloy X may be discharge | released well.

  Next, the hydrogen storage alloy X filled in the hydrogen storage alloy container 5 will be described.

  The hydrogen storage alloy X of the present embodiment is a hydrogen storage alloy having different characteristics between the hydrogen pressure and composition (hydrogen storage amount) of the hydrogen storage alloy at a predetermined temperature, so-called PCT (Pressure Composition Temperature) characteristics. A mixture of a plurality of types.

  FIG. 3 shows typical PCT characteristics of a hydrogen storage alloy and the amount of heat generated during hydrogen storage, in other words, the amount of heat absorbed by the refrigerant that cools the hydrogen storage alloy. The hydrogen storage alloy generally increases the hydrogen storage amount when the hydrogen pressure, that is, the pressure in the hydrogen storage alloy container 5 increases, and passes through a region (plateau region) where the hydrogen storage amount increases at a certain pressure (plateau pressure). Thereafter, the occlusion amount with respect to the pressure increase is blunted. The calorific value of the hydrogen storage alloy having such a PCT characteristic has a tendency that the calorific value becomes the maximum at the plateau pressure, and the calorific value also decreases when the hydrogen storage amount per unit pressure (or per unit time) decreases. Show.

  This PCT characteristic is different depending on the hydrogen storage alloy as described above. For example, as shown in FIG. 4, it is possible to select a hydrogen storage alloy with a difference in plateau pressure.

  Here, when hydrogen is stored with a single hydrogen storage alloy as shown in FIG. 3, the performance of the refrigerant piping, the pump 21, the motor 22 and the like constituting the heat exchange system that controls the heat dissipation of the hydrogen storage alloy. As the performance and specification corresponding to the maximum heat dissipation amount of the hydrogen storage alloy at the plateau pressure, it is necessary to increase the diameter and thickness of the refrigerant pipe, increase the capacity of the pump 21 and increase the output of the motor 22. For this reason, a heat exchange system part will lead to an increase in size and cost.

  Therefore, the present embodiment is characterized in that the hydrogen storage alloy X filled in the hydrogen storage alloy container 5 is composed of a plurality of types of hydrogen storage alloys A to E having different PCT characteristics. The effect of using a plurality of types of hydrogen storage alloys X having different hydrogen storage characteristics will be described with reference to FIG.

  FIG. 4 shows the hydrogen storage characteristics of five types of hydrogen storage alloys A to E filled in the hydrogen storage alloy container. This hydrogen storage characteristic is a so-called PCT characteristic, and the hydrogen storage alloys A to E are hydrogen storage alloys that are between the upper limit pressure and the lower limit pressure at the use environment temperature of the vehicle on which the plateau pressure of each PCT characteristic is mounted. Then, the hydrogen storage alloys A to E are selected so that the plateau pressure difference is generated at substantially equal intervals. Further, each hydrogen storage alloy is selected such that the total hydrogen storage amount of the hydrogen storage alloys A to E is substantially equal to the single hydrogen storage alloy shown in FIG. Here, the upper limit pressure is an allowable pressure of the high-pressure hydrogen storage container 1, and the lower limit pressure is set from a required hydrogen supply pressure, and corresponds to, for example, the lowest hydrogen supply pressure capable of generating power in the fuel cell stack 14. Pressure.

  As described above, each of the hydrogen storage alloys A to E has a different plateau pressure, and the amount of each hydrogen storage alloy A to E filled in the hydrogen storage alloy container 5 is one type of hydrogen storage alloy. Therefore, the heat dissipation amount of each of the hydrogen storage alloys A to E is reduced, and the pressure generated by the maximum heat dissipation amount does not match. For this reason, as shown in the figure, the total heat dissipation amount of the hydrogen storage alloys A to E is a trapezoidal characteristic in which the maximum heat dissipation amount is maintained, and the heat dissipation characteristics can be set so that the time (pressure) in which the maximum heat dissipation occurs is increased. . Therefore, if the total heat dissipation amount A of the single hydrogen storage alloy shown in FIG. 3 and the total heat dissipation amount B of the plurality of types of hydrogen storage alloys shown in FIG. 4 are the same, the maximum heat dissipation amount per unit time is a plurality of types of hydrogen. It is clear that the storage alloy is smaller.

  In addition, you may select so that the ratio of the hydrogen storage alloy with many hydrogen storage amounts may increase so that the amount of hydrogen storage may increase, reducing the maximum heat dissipation per unit time.

  In this way, by configuring the hydrogen storage alloy filled in the hydrogen storage alloy container 5 from the plurality of hydrogen storage alloys A to E having different plateau pressures, the maximum heat dissipation amount per unit time is maintained while maintaining the hydrogen storage amount. Can be reduced. By reducing the maximum heat radiation amount per unit time, the refrigerant flow rate is lowered, and as a result, the diameter and thickness of the refrigerant pipe can be reduced, the pump 21 and the motor 22 can be downsized, and the heat exchange system unit. Can be reduced in size, weight, and cost. Further, since a plurality of hydrogen storage alloys are mixed and filled into the hydrogen storage alloy container 5, the conventional hydrogen storage alloy container can be used without change.

(Reference example)
Next, a method of filling the hydrogen storage alloy in the hydrogen storage alloy container will be described with reference to the drawings.

  In FIG. 2 described above, the hydrogen storage alloy container 5 is filled with a plurality of hydrogen storage alloys mixed. On the other hand, in the method shown in FIG. 5, the interior of the hydrogen storage alloy container 5 is partitioned using the partition plate 7, and each of the hydrogen storage alloys A to E is filled in each partition. The partition plate 7 that partitions the hydrogen storage alloys A to E is formed in a cylindrical shape having a different diameter so as to be installed concentrically, and the partition plate 7 is not mixed with the hydrogen storage alloys A to E. In addition, for example, a mesh shape is formed so that hydrogen can pass through. In the hydrogen storage alloy container 5, refrigerant tubes 6b are arranged at equal intervals to cool the generated hydrogen storage alloys A to E.

  FIG. 6 shows a partial cross-sectional view in the vicinity of the refrigerant pipe 6b. A disk-shaped fin 6f fixed to the refrigerant pipe 6b and extending in the direction perpendicular to the axis is provided, and a partition plate 7 for partitioning each hydrogen storage alloy on the fin 6f. To fix.

  Further, the hydrogen storage alloys A to E are filled with the hydrogen storage alloy A having a lower plateau pressure on the outer peripheral side, and filled with the hydrogen storage alloy E having a higher plateau pressure toward the inner side, and the refrigerant is first radiated with heat from the outer hydrogen storage alloy A. By supplying it so that it can be used, the heat exchange of the hydrogen storage alloy can be performed efficiently.

  In addition, if the partition plate 7 is used, the inside of the hydrogen storage alloy container 5 can be arbitrarily divided, and heat exchange between the hydrogen storage alloy and the refrigerant can be efficiently performed by appropriately arranging hydrogen storage alloys having different PCT characteristics. It can be carried out.

  Further, in the present embodiment, for example, hydrogen storage alloys represented by TiZrCrFeNiMnCu (AB2), TiCrV (BCC), and MmNiMnCo (AB5) alloys have been described as examples. MOF (porous metal organic structural material) that is a hydrogen storage material that stores hydrogen may be used. Needless to say, not only occlusion but also a hydrogen adsorbing material that adsorbs hydrogen, such as a complex carbon material, a carbon nanotube, a carbon nanocube, or activated carbon, may be used. Furthermore, the present invention is applicable to any material that has PCT characteristics and generates heat in and out during hydrogen storage (adsorption) and release.

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made within the scope of the technical idea, and it is obvious that these are equivalent to the present invention.

It is a block diagram of the fuel cell system of 1st Embodiment. It is a block diagram of a high pressure hydrogen storage container. It is a figure which shows the PCT characteristic of one type of hydrogen storage alloy. It is a figure which shows the PCT characteristic of multiple types of hydrogen storage alloy. It is a block diagram of another high pressure hydrogen storage container. It is a fragmentary sectional view near a refrigerant pipe.

Explanation of symbols

1: High pressure hydrogen storage container 2: Liner 3: Reinforcing member 4a, 4b: Valve unit 5: Hydrogen storage alloy container 6: Refrigerant pipe 6a: Collecting part 6b: Refrigerant pipe 7: Partition plates A to E, X: Hydrogen storage alloy

Claims (4)

A hydrogen container filled with a material that absorbs or adsorbs hydrogen; and
In a high-pressure hydrogen storage container provided with a liner that houses this hydrogen container,
In the hydrogen container, a refrigerant pipe through which a refrigerant for cooling the material flows is provided,
The material comprises a plurality of materials having different plateau pressures and different properties for occluding or adsorbing hydrogen,
The plurality of materials are mixed and filled into the hydrogen container ,
A high-pressure hydrogen storage container, wherein the difference in plateau pressure among the plurality of materials is equal .   2. The high-pressure hydrogen storage container according to claim 1, wherein the plateau pressure of each of the materials is maintained in a predetermined pressure range at a use environment temperature of a vehicle on which the high-pressure hydrogen storage container is mounted.   The high pressure hydrogen storage container according to claim 2, wherein the upper limit pressure of the pressure range is an allowable pressure of the high pressure hydrogen storage container, and the lower limit pressure is a required minimum hydrogen supply pressure. The high-pressure hydrogen storage container according to any one of claims 1 to 3 , wherein the amount of each material is set so that the amount of heat generated by the occlusion or adsorption of hydrogen of each material becomes equal.