Hydrogen absorption and discharge device and hydrogen absorption and discharge module

Abstract

To provide a hydrogen absorption and discharge device and a hydrogen absorption and discharge module that can improve efficiency of storage and transportation of hydrogen.SOLUTION: A hydrogen absorption and discharge device according to an embodiment comprises: an absorption and discharge section including a material capable of permeation of hydrogen and hydride ion conduction; a first electrode provided on the side of a first end of the absorption and discharge section; a second electrode provided on the side of a second end of the absorption and discharge section that faces the first end; and buffer layers respectively provided between the first electrode and the first end of the absorption and discharge section, and between the second electrode and the second end of the absorption and discharge section.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a hydrogen absorption and discharge device and a hydrogen absorption and discharge module. [Background technology]

[0002] The use of hydrogen has been increasing in recent years. For example, carbon dioxide is produced when fossil fuels such as coal, oil, and natural gas are burned, but carbon dioxide is not produced when hydrogen is burned. For this reason, the use of hydrogen is desirable from the perspective of environmental protection.

[0003] Here, hydrogen needs to be stored and transported when it is used as a fuel or raw material, etc. Proposed technologies for storing and transporting hydrogen include storing compressed hydrogen in high-pressure cylinders, storing liquefied hydrogen in tanks, reacting hydrogen with toluene to form methylcyclohexane (organic halide), using ammonia as a medium for storing and transporting hydrogen, and storing hydrogen in a hydrogen storage alloy.

[0004] However, these technologies have problems such as safety issues during storage and transportation, and the weight increases, making hydrogen storage and transportation less efficient. Therefore, there is a need to develop technology that can improve the efficiency of hydrogen storage and transportation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-071811 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a hydrogen absorption / discharge device and a hydrogen absorption / discharge module that can improve the efficiency of hydrogen storage and transportation. [Means for solving the problem]

[0007] The hydrogen absorption / discharge device according to the embodiment comprises an absorption / discharge section containing a material capable of hydrogen permeation and hydride ion conductivity, a first electrode provided on the side of a first end of the absorption / discharge section, a second electrode provided on the side of a second end of the absorption / discharge section opposite the first end, and buffer layers provided between the first electrode and the first end of the absorption / discharge section, and between the second electrode and the second end of the absorption / discharge section. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view illustrating a hydrogen absorption and discharge device according to an embodiment of the present invention. [Figure 2] 1 is a graph illustrating the temperature dependence of the electrical conductivity of titanium nitride. [Figure 3] FIG. 2 is a schematic perspective view illustrating a hydrogen absorption / discharge module. [Figure 4] FIG. 2 is a schematic perspective view illustrating a hydrogen absorption / discharge module. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be illustrated with reference to the drawings. In the drawings, like components are designated by like reference numerals and detailed descriptions thereof will be omitted where appropriate. FIG. 1 is a schematic cross-sectional view illustrating a hydrogen absorption and discharge device 1 according to the present embodiment. As shown in FIG. 1, the hydrogen absorption / discharge device 1 includes, for example, an absorption / discharge section 2, an electrode 3 (corresponding to an example of a first electrode), an electrode 4 (corresponding to an example of a second electrode), and a buffer layer 5.

[0010] The intake and exhaust unit 2 has, for example, an end 2a (corresponding to an example of a first end) and an end 2b (corresponding to an example of a second end) opposite to end 2a. At a predetermined temperature, the intake and exhaust unit 2 can switch between absorbing hydrogen and discharging the absorbed hydrogen depending on the polarity of the voltage applied to end 2a or end 2b.

[0011] The intake / exhaust section 2 contains, for example, a material that allows hydrogen permeation and hydride ion conductivity. The intake / exhaust section 2 can contain, for example, BawLixHyOz. Note that, for example, w = 0.1 to 3.0, x = 0.1 to 2.0, y = 0.1 to 5.0, and z = 0.1 to 2.0. In this case, if the intake / exhaust unit 2 contains BawLixHyOz, hydrogen can be absorbed and discharged at temperatures of about 300° C. to 340° C. In other words, hydrogen can be absorbed and discharged at a relatively low temperature, which makes it easier to absorb and discharge hydrogen.

[0012] There are no particular limitations on the form of the intake and exhaust section 2. For example, the intake and exhaust section 2 may be in the shape of a film, a plate, a block, a column, or the like. There are no particular limitations on the shape of the intake and exhaust section 2 when viewed from the direction from end 2a to end 2b. For example, the shape of the intake and exhaust section 2 may be a circle, a polygon such as a square or a hexagon, or a shape composed of straight lines and curves.

[0013] The amount of hydrogen that can be absorbed can be increased by increasing the volume of the intake and exhaust section 2. However, if the volume of the intake and exhaust section 2 is made too large, chipping and cracking can easily occur in the intake and exhaust section 2. Therefore, the volume of the intake and exhaust section 2 can be set appropriately depending on the required amount of hydrogen that can be absorbed and the rigidity of the intake and exhaust section 2 that is due to the material.

[0014] The electrode 3 is provided, for example, on the side of the end 2a of the intake and exhaust part 2. The electrode 4 is provided, for example, on the side of the end 2b of the intake and exhaust part 2. Electrode 3 and electrode 4 are formed from a conductive material such as a metal. In this case, the ionization tendency of the material of electrode 3 can be greater than the ionization tendency of the material of electrode 4. The material of electrode 3 can be, for example, titanium (Ti). The material of electrode 4 can be, for example, palladium (Pd).

[0015] Here, materials capable of hydride ion conductivity have high reducing properties, so when electrodes 3 and 4 come into contact with the intake / exhaust unit 2, electrodes 3 and 4 are reduced, which may cause the electrodes 3 and 4 to lose their electrical conductivity.

[0016] Therefore, a buffer layer 5 is provided between the electrode 3 and the end 2a of the intake / exhaust unit 2, and between the electrode 4 and the end 2b of the intake / exhaust unit 2. The buffer layer 5 can be formed from a material that is resistant to reduction by a material capable of hydride ion conductivity and that can maintain conductivity at temperatures at which hydrogen is absorbed and released. The buffer layer 5 is also permeable to hydrogen.

[0017] As described above, when the material capable of hydride ion conductivity is BawLixHyOz, the temperature at which hydrogen absorption and desorption occur is approximately 300°C to 340°C. Therefore, the buffer layer 5 can be formed from a material that can maintain conductivity at temperatures of approximately 300°C to 340°C. For example, the buffer layer 5 can include a polycrystalline film containing a nitride of titanium, tantalum (Ta), or the like, a perovskite compound, a hydrogen-containing perovskite compound, or a hydrate of at least one of a perovskite compound and a hydrogen-containing perovskite compound.

[0018] According to the findings of the present inventors, for example, if the buffer layer 5 contains titanium nitride (TiN), it is possible to suppress the reduction of the electrodes 3 and 4 caused by a material capable of hydride ion conductivity, and it is possible to maintain the conductivity of the buffer layer 5 at temperatures of about 300°C to 340°C.

[0019] FIG. 2 is a graph illustrating the temperature dependence of the electrical conductivity of titanium nitride. Note that the ● in Figure 2 represents a film containing titanium nitride. The thickness of the film containing titanium nitride is 300 nm. The broken line in Figure 2 represents a film containing molybdenum (Mo). For example, molybdenum is sometimes used as a material for electrodes that require heat resistance. Molybdenum in Figure 2 is a comparative example as an electrode material that requires heat resistance.

[0020] As can be seen from FIG. 2, if the buffer layer 5 is made of titanium nitride, high conductivity (low electrical resistance) can be obtained in a temperature range of 300°C or higher. For example, if the buffer layer 5 is made of titanium nitride, conductivity equivalent to that of molybdenum can be obtained in a temperature range of 300°C or higher. However, since molybdenum begins to oxidize at around 400°C, it may deteriorate over time at temperatures of around 300°C to 340°C. Therefore, molybdenum cannot be used for the buffer layer 5 from the viewpoint of its lifespan.

[0021] If the material of the buffer layer 5 is titanium nitride, the reduction of the electrodes 3 and 4 can be suppressed by BawLixHyOz, and the electrodes 3 and 5, and the electrodes 4 and 5 can each function as electrodes in the temperature range of 300°C or higher.

[0022] If the thickness of the buffer layer 5 is too thin, pinholes may occur, which may result in the electrodes 3 and 4 being reduced by BawLixHyOz. If the thickness of the buffer layer 5 is too thick, the resistance of the buffer layer 5 may increase, which may increase the voltage applied to the hydrogen absorption / desorption device 1 when absorbing and desorbing hydrogen, or may reduce the responsiveness of absorption and desorption. For example, if the buffer layer 5 contains titanium nitride, the thickness of the buffer layer 5 is preferably about several hundred nanometers (for example, about 100 nm to 500 nm).

[0023] The electrode 3, the electrode 4, and the buffer layer 5 can be formed sequentially on the ends 2a and 2b of the intake and exhaust unit 2 using a film formation method such as sputtering or CVD (Chemical Vapor Deposition). Alternatively, the electrode 3 and the buffer layer 5 may be formed integrally, and the integrally formed electrode 3 and buffer layer 5 may be pressure-bonded to the end 2a of the intake and exhaust unit 2. The electrode 4 and the buffer layer 5 may be formed integrally, and the integrally formed electrode 4 and buffer layer 5 may be pressure-bonded to the end 2b of the intake and exhaust unit 2.

[0024] The intake and exhaust section 2 can be formed, for example, by heating and pressurizing powder of the target material. Alternatively, the intake and exhaust section 2 may be formed using a film formation method such as physical vapor deposition (PVD) or sputtering.

[0025] Next, the operation of the hydrogen absorption and discharge device 1 will be described. When hydrogen is absorbed into the hydrogen absorption / discharge device 1, the temperature of the hydrogen absorption / discharge device 1 is set to a predetermined temperature, and hydrogen is supplied to the hydrogen absorption / discharge device 1. Then, a negative voltage is applied to the electrode 3, or a positive voltage is applied to the electrode 4. For example, the negative electrode of a DC power supply is electrically connected to the electrode 3, and the positive electrode of the DC power supply is electrically connected to the electrode 4, and a predetermined DC current is passed from the electrode 3 side to the electrode 4 side of the absorption / discharge unit 2.

[0026] At a predetermined temperature, when a predetermined current flows through the intake and exhaust unit 2 from the electrode 3 side toward the electrode 4 side, hydrogen is adsorbed and held (absorbed) in the intake and exhaust unit 2. In this case, if the current continues to flow through the intake and exhaust unit 2, hydrogen is absorbed up to the absorption limit of the intake and exhaust unit 2.

[0027] For example, if the intake and exhaust unit 2 includes BawLixHyOz, the temperature of the intake and exhaust unit 2 can be set to about 300°C to 340°C. The current that can flow through the intake and exhaust unit 2 may vary depending on the size of the intake and exhaust unit 2. The current that flows through the intake and exhaust unit 2 is, for example, about 10 μA to 10 A.

[0028] When hydrogen stored in the hydrogen absorption / discharge device 1 is to be discharged, the temperature of the hydrogen absorption / discharge device 1 is set to a predetermined temperature, and a positive voltage is applied to the electrode 3. Alternatively, a negative voltage is applied to the electrode 4. For example, the positive electrode of a DC power supply is electrically connected to the electrode 3, and the negative electrode of the DC power supply is electrically connected to the electrode 4, and a predetermined DC current is passed through the absorption / discharge unit 2 from the electrode 4 side to the electrode 3 side.

[0029] When a predetermined current flows through the intake and exhaust unit 2 from the electrode 4 side toward the electrode 3 side at a predetermined temperature, the hydrogen absorbed in the intake and exhaust unit 2 is exhausted. The temperature of the intake / exhaust unit 2 when discharging hydrogen can be, for example, the same as the temperature of the intake / exhaust unit 2 when absorbing hydrogen, as described above. Also, the value of the current passed to discharge hydrogen can be, for example, the same as the value of the current passed when absorbing hydrogen, as described above.

[0030] That is, by switching the polarity of the voltage applied to electrode 3 and electrode 4 (the direction of the current flowing through the absorption / discharge unit 2), it is possible to switch between hydrogen absorption and hydrogen discharge. Therefore, it is possible to improve the efficiency of the operation of hydrogen absorption and hydrogen discharge. That is, the hydrogen absorption and discharge device 1 according to this embodiment can improve the efficiency of storing and transporting hydrogen.

[0031] FIG. 3 is a schematic perspective view illustrating the hydrogen absorption and discharge module 100. As shown in FIG. As shown in FIG. 3, the hydrogen absorption / discharge module 100 includes, for example, the hydrogen absorption / discharge device 1, a container 101, a terminal 102, and a terminal 103.

[0032] At least one hydrogen absorption / discharge device 1 can be provided. 3 is provided with three hydrogen absorption-discharge devices 1. By providing multiple hydrogen absorption-discharge devices 1, the amount of hydrogen that can be absorbed can be increased.

[0033] When multiple hydrogen absorption-discharge devices 1 are provided, the multiple hydrogen absorption-discharge devices 1 can be connected in series, for example. For example, as shown in FIG. 3, an electrode 4 provided on one hydrogen absorption-discharge device 1 can be electrically connected to an electrode 3 provided on an adjacent hydrogen absorption-discharge device 1. For example, the electrode 4 and the electrode 3 can be joined by laser welding or the like. In this case, since the configuration of the hydrogen absorption-discharge devices 1 connected in series is the same, the amount of hydrogen absorbed can be easily changed simply by changing the number of hydrogen absorption-discharge devices 1.

[0034] The container 101 houses the hydrogen absorption / discharge device 1. There are no particular limitations on the shape of the container 101. The container 101 illustrated in Fig. 3 has a cylindrical shape with both ends closed.

[0035] Here, if the absorption / discharge section 2 provided in the hydrogen absorption / discharge device 1 contains BawLixHyOz, there is a risk that BawLixHyOz will sublimate when moisture contained in the atmosphere comes into contact with BawLixHyOz. Therefore, the container 101 is made of a material that is difficult for moisture contained in the atmosphere to permeate.

[0036] Furthermore, when the above-described hydrogen absorption and discharge is performed, the container 101 containing the hydrogen absorption and discharge device 1 may be heated. That is, the hydrogen absorption and discharge device 1 may be heated via the container 101. Therefore, the melting point of the material of the container 101 can be made higher than at least the heating temperature of the absorption and discharge section 2. Therefore, the container 101 can be made of a metal such as stainless steel.

[0037] The terminal 102 is made of a conductive material such as metal. The terminal 102 and the container 101 are insulated from each other. One end of the terminal 102 is electrically connected to the electrode 3 of the hydrogen absorption and discharge device 1 housed in the container 101. The one end of the terminal 102 can be joined to the electrode 3 by, for example, laser welding. The other end of the terminal 102 is exposed to the outside of the container 101.

[0038] The terminal 103 is made of a conductive material such as metal. The terminal 103 and the container 101 are insulated from each other. One end of the terminal 103 is electrically connected to the electrode 4 of the hydrogen absorption and discharge device 1 housed in the container 101. The one end of the terminal 103 can be joined to the electrode 4 by, for example, laser welding. The other end of the terminal 103 is exposed to the outside of the container 101.

[0039] When absorbing and discharging hydrogen, a power supply circuit 200 or the like can be electrically connected to terminals 102 and 103 exposed to the outside of container 101. The polarity of the applied voltage (the direction of the current flowing through absorption and discharge unit 2) can be switched in the same manner as described above when absorbing and discharging hydrogen.

[0040] In this case, when storing and discharging hydrogen, the hydrogen absorption and discharge device 1 can be heated via the container 101. Therefore, the heating range can be reduced, thereby achieving energy savings.

[0041] Furthermore, when hydrogen is absorbed, hydrogen can be supplied to the inside of the container 101. When hydrogen is discharged, hydrogen can be extracted through the container 101. This makes it possible to suppress the diffusion of supplied hydrogen and discharged hydrogen. This makes it possible to reduce the amount of hydrogen consumed and improve the efficiency of hydrogen extraction.

[0042] When transporting the stored hydrogen, the ends of terminals 102 and 103 exposed to the outside of container 101 can be covered with an insulating cover or the like.

[0043] Furthermore, a lid and a valve for supplying and discharging hydrogen can be provided to the container 101. In this case, it is preferable that the lid and the valve have an airtight structure that can prevent moisture contained in the atmosphere from entering the inside of the container 101.

[0044] Furthermore, when storing and discharging hydrogen, piping can be connected to the container 101. The piping may be connected, for example, by drilling a hole or the like in the container 101, by removing the lid of the container 101, or by connecting via a valve or the like of the container 101.

[0045] Furthermore, when absorbing and discharging hydrogen, holes or cuts can be formed in the container 101. When the absorption of hydrogen is completed, the holes or cuts formed in the container 101 can be closed by, for example, laser welding.

[0046] FIG. 4 is a schematic perspective view illustrating the hydrogen absorption and discharge module 100a. As shown in FIG. 4, the hydrogen absorption and discharge module 100a includes, for example, the hydrogen absorption and discharge device 1, a container 101, a terminal 102a, a terminal 103a, a connection plate 104, and a connection plate 105.

[0047] At least one hydrogen absorption / discharge device 1 can be provided. 4 is provided with three hydrogen absorption-discharge devices 1. By providing multiple hydrogen absorption-discharge devices 1, the amount of hydrogen that can be absorbed can be increased.

[0048] The hydrogen absorption / discharge module 100 illustrated in FIG. 3 is provided with a plurality of hydrogen absorption / discharge devices 1 connected in series. In contrast to this, the hydrogen absorption / discharge module 100a illustrated in FIG. 4 is provided with a plurality of hydrogen absorption / discharge devices 1 connected in parallel.

[0049] For example, the electrodes 3 of a plurality of hydrogen absorption and discharge devices 1 can be electrically connected to the connection plate 104. For example, the electrodes 3 and the connection plate 104 can be joined by laser welding or the like.

[0050] For example, the electrodes 4 of a plurality of hydrogen absorption and discharge devices 1 can be electrically connected to the connection plate 105. For example, the electrodes 4 and the connection plate 105 can be joined by laser welding or the like.

[0051] The connection plates 104 and 105 can be, for example, strip-shaped and made of a conductive material such as copper. In this way, the connection plates 104 and 105 can connect multiple hydrogen absorption-discharge devices 1 in parallel. In this case, the configuration of the hydrogen absorption-discharge devices 1 connected in parallel is the same, so the amount of hydrogen absorption and discharge can be easily changed simply by changing the number of hydrogen absorption-discharge devices 1.

[0052] It is also possible to connect multiple hydrogen absorption and discharge devices 1 in parallel using the electrodes 3 and 4. For example, the absorption and discharge sections 2 provided with the buffer layer 5 can be arranged side by side between the strip-shaped electrodes 3 and 4. In this way, the connection plates 104 and 105 can be omitted, and the hydrogen absorption and discharge module 100a can be made smaller.

[0053] However, the electrode 3 is made of titanium, and the electrode 4 is made of palladium. Therefore, if the size of the electrodes 3 and 4 increases, the manufacturing cost of the hydrogen absorption and discharge module 100a may increase. Therefore, the configuration when multiple hydrogen absorption-discharge devices 1 are connected in parallel can be changed as appropriate depending on the size and manufacturing cost required for the hydrogen absorption-discharge module 100a.

[0054] Here, whether multiple hydrogen absorption / discharge devices 1 are connected in series or in parallel, it is thought that the amount of hydrogen absorbed will be approximately the same as long as the number of hydrogen absorption / discharge devices 1 is the same.

[0055] However, if the number of hydrogen absorption-exhaust devices 1 connected in series increases, the resistance value of the hydrogen absorption-exhaust module 100 increases, which may reduce the current flowing through the absorption-exhaust unit 2. In this case, if the voltage applied to the hydrogen absorption-exhaust module 100 is increased to increase the current flowing through the absorption-exhaust unit 2, power consumption will increase. Therefore, from the viewpoint of energy saving, it is preferable to connect a plurality of hydrogen absorption and discharge devices 1 in parallel.

[0056] Although several embodiments of the present invention have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other. [Explanation of symbols]

[0057] 1 hydrogen absorption / exhaust device, 2 absorption / exhaust section, 2a end, 2b end, 3 electrode, 4 electrode, 5 buffer layer, 100 hydrogen absorption / exhaust module, 100a hydrogen absorption / exhaust module, 101 container, 102 terminal, 103 terminal, 102a terminal, 103a terminal, 104 connection plate, 105 connection plate

Claims

1. an intake and exhaust portion including a material capable of hydrogen permeation and hydride ion conductivity; a first electrode provided on the side of a first end of the intake and exhaust unit; a second electrode provided on a second end side of the intake and exhaust unit opposite to the first end; a buffer layer provided between the first electrode and the first end of the intake and exhaust unit, and between the second electrode and the second end of the intake and exhaust unit; A hydrogen intake and exhaust device equipped with the device.

2. The intake and exhaust section is The hydrogen can be absorbed by a current flowing from the first electrode side to the second electrode side, 2. The hydrogen absorption / exhaust device according to claim 1, wherein the absorbed hydrogen can be discharged by flowing a current from the second electrode side to the first electrode side.

3. 3. The hydrogen absorption and discharge device according to claim 1, wherein the absorption and discharge section contains BawLixHyOz, where w=0.1 to 3.0, x=0.1 to 2.0, y=0.1 to 5.0, and z=0.1 to 2.

0.

4. 3. The hydrogen absorption and discharge device according to claim 1, wherein the buffer layer contains a metal nitride and is permeable to the hydrogen.

5. At least one hydrogen absorption / discharge device according to claim 1 or 2; a container in which the hydrogen absorption and discharge device is housed; a first terminal, one end of which is electrically connected to a first electrode of the hydrogen absorption and discharge device housed in the container, and the other end of which is exposed to the outside of the container; a second terminal, one end of which is electrically connected to a second electrode of the hydrogen absorption / discharge device housed in the container and the other end of which is exposed to the outside of the container; A hydrogen intake and exhaust module equipped with

Images