Metal-air battery

Abstract

A metal-air battery that can shorten the apparent charging time is provided. The metal-air battery 10 has a fuel material body 12, a first internal space 14, and a second internal space 16. The fuel material body 12 reacts with water vapor to produce hydrogen gas and becomes an oxide itself. The first internal space 14 accommodates the fuel material body 12 in an airtight manner. The second internal space 16 includes a flat fuel cell 18. The flat fuel cell 18 includes a solid oxide membrane 18a that conducts oxygen ions, an air electrode 18b on one surface thereof, and an anode 18c on the other surface thereof. The air electrode 18b reduces oxygen in the air to oxygen ions during discharge. The anode 18c oxidizes hydrogen gas to water vapor using the oxygen ions during discharge. The first internal space 14 is detachable.

Description

[Technical Field]

[0001] The present invention relates to a metal-air battery that can be charged as well as discharged, and more particularly to a metal-air battery that uses metal powder or particles such as iron powder to regenerate fuel gas within the system. [Background technology]

[0002] Fuel cells are a means of generating electricity by supplying fuel gas to a power generator. Among fuel cells, solid oxide fuel cells (SOFCs), which use an inorganic solid electrolyte with oxygen ion conductivity, are known to be clean, highly efficient, and excellent power generation devices. In addition, metal-air batteries have been developed that can be used as secondary batteries by restoring the fuel gas consumed by the discharge of fuel cells.

[0003] Patent Document 1 describes a metal-air battery having a solid electrolyte body, an anode, a cathode, an anode fuel material body, a heating portion, and a sealing portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5210450 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not take into consideration the replacement of a fully discharged anode fuel material with a fully charged anode fuel material, and therefore has the problem that the charging time cannot be shortened.

[0006] The present invention has been made in view of the above-mentioned problems in the prior art, and an object of the present invention is to provide a metal-air battery that can shorten the apparent charging time. [Means for solving the problem]

[0007] That is, the present invention provides a fuel cell comprising: a fuel material that reacts with water vapor to produce hydrogen gas and becomes an oxide itself; a first internal space in which the fuel material is hermetically housed; a second internal space provided with a flat fuel cell cell that has an air electrode that reduces oxygen in the air to oxygen ions during discharge on one surface of a solid oxide film that conducts oxygen ions, and a fuel electrode that oxidizes hydrogen gas to water vapor by the oxygen ions during discharge on the other surface; a flow path that connects the first internal space and the second internal space; With death , first interior space Fuel container that constitutes teeth, In the middle of the flow path with respect to the main body container constituting the second internal space It is detachable Money The present invention provides a metal-air battery.

[0008] Furthermore, Akira is , a fuel material that reacts with water vapor to produce hydrogen gas and becomes an oxide itself; a first internal space in which the fuel material is hermetically contained; and a second internal space containing a flat fuel cell cell that has an air electrode that reduces oxygen in the air to oxygen ions during discharge on one surface of a solid oxide film that conducts oxygen ions, and an anode that oxidizes hydrogen gas to water vapor with the oxygen ions during discharge on the other surface. A cooling gas introduction device for introducing and discharging cooling gas into the first internal space and, With The fuel container forming the first internal space is detachable from the main container forming the second internal space. . [Effects of the Invention]

[0009] The metal-air battery of the present invention can reduce the apparent charging time. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a metal-air battery of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing a fuel cell constituting the metal-air battery of FIG. 1 and its surroundings. [Figure 3] 2 is a cross-sectional view showing a fuel exchange system for a vehicle equipped with the metal-air battery of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] The metal-air battery of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings. Fig. 1 is a cross-sectional view showing the metal-air battery of the present invention, and Fig. 2 is a cross-sectional view showing a fuel cell and its periphery that constitute the metal-air battery of Fig. 1.

[0012] The metal-air battery 10 has a fuel material body 12, a first internal space 14, and a second internal space 16. The fuel material body 12 reacts with water vapor to produce hydrogen gas and becomes an oxide. The first internal space 14 accommodates the fuel material body 12 in an airtight manner. The second internal space 16 contains a flat fuel cell 18. The flat fuel cell 18 has a solid oxide membrane 18a that conducts oxygen ions, an air electrode 18b on one surface, and an anode 18c on the other surface. The air electrode 18b reduces oxygen in the air to oxygen ions during discharge. The anode 18c oxidizes hydrogen gas to water vapor using the oxygen ions during discharge. The first internal space 14 is detachable. By adopting such a configuration, the metal-air battery of the present invention can shorten the apparent charging time.

[0013] The metal-air battery 10 may further include a cooling gas introduction device 20. In this case, the cooling gas introduction device 20 introduces and exhausts cooling gas into the first internal space 14. When the metal-air battery 10 is mounted on a vehicle, it is preferable that the cooling gas introduction device 20 be installed on the ground rather than mounted on the vehicle. With this configuration, the metal-air battery of the present invention allows the first internal space 14 to be attached and detached safely.

[0014] The fuel container 22 defines a first internal space 14 therein. A first covering body 24 is preferably disposed between the outer surface of the fuel container 22 and the external environment to provide thermal insulation between them. The main container 26 defines a second internal space 16 therein. A second covering body 28 is preferably disposed between the outer surface of the main container 26 and the external environment to provide thermal insulation between them. A joining body 30 is preferably disposed between the fuel cell 18 and the main container 26 to join them. The flow path 32 is a part of the first internal space 14 or a part of the second internal space 16, connecting them. The flow path opening / closing device 34 opens and closes the flow path 32. To prevent gas from escaping from the second internal space 16 and cooling gas from entering the second internal space 16, the flow path 32 is preferably closed before starting the fuel material 12 replacement operation and opened after the replacement operation is completed.

[0015] Next, the fuel exchange system will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view showing the fuel exchange system for the mobile body equipped with the metal-air battery of Fig. 1. The fuel exchange system 40 includes a mobile body 42 equipped with a metal-air battery 10 and an elevator device 44. The elevator device 44 is disposed on or below the floor surface along which the mobile body 42 moves, and moves the fuel container 22 and the first cladding 24 disposed on its outer surface in a direction perpendicular to the floor surface along which the mobile body 42 moves. The first cladding 24a represents a first cladding that has been removed from the mobile body 42 because the remaining amount of fuel is low, and the first cladding 24b represents a fully charged first cladding that is to be installed into the mobile body 42.

[0016] The cooling gas introduction device 20 preferably includes a nitrogen gas container 20a, a water container 20b, and water 20c. The nitrogen gas container 20a is a container of nitrogen gas for cooling the fuel container 22, and the water container 20b is a container of water 20c for generating water vapor. The cooling gas introduction device 20 has the function of supplying and discharging nitrogen gas for cooling to the first internal space 14 of the metal-air battery 10 mounted on the mobile object 42, and the function of supplying water vapor together with the nitrogen gas to replenish the first internal space 14 instead of hydrogen gas. The water vapor may be replenished either during or after charging the metal-air battery 10.

[0017] Next, the fuel material constituting the metal-air battery of the present invention will be described. The fuel material 12 is not particularly limited as long as it reacts with water vapor to produce hydrogen gas and becomes an oxide. However, it is preferably a pellet-shaped material composed of iron particles or iron powder and a shape-retaining material. The shape-retaining material is a sinter-resistant material or a mixture thereof. Examples of sinter-resistant materials include aluminum oxide, silicon dioxide, magnesium oxide, and zirconium oxide. At least a portion of the surface of the fuel material 12 is covered with the shape-retaining material, and the mass ratio of the shape-retaining material to the fuel material 12 is 0.1% or more and 5% or less. If this mass ratio is less than 0.1%, the surface of the fuel material 12 may sinter, preventing the oxidation-reduction reaction from occurring. If it is more than 5%, the oxidation-reduction rate may be excessively suppressed. The pellet diameter is, for example, 2 to 10 mm.

[0018] Next, the operating temperature of the metal-air battery of the present invention will be described. The temperature of the fuel cell 18 may be 450 to 1000°C, and the temperature of the fuel material 12 may be 300 to 1000°C. Specifically, if the temperature of the fuel cell 18 is below 450°C or the temperature of the fuel material 12 is below 300°C, the metal-air battery 10 may not operate. If the temperature of the fuel cell 18 exceeds 1000°C or the temperature of the fuel material 12 exceeds 1000°C, a decrease in output due to aggregation of the fuel material 12 may occur. Furthermore, if the temperature of the interconnected first and second internal spaces 14 and 16 increases, for example, from 22°C to 730°C, the volume does not change, and the pressure increases by approximately 3.4 times according to Boyle's law. Therefore, for a given thickness of the fuel cell 18, the larger the size of the fuel cell 18, the more likely the fuel cell 18 is to be damaged.

[0019] Next, the state of the metal-air battery of the present invention during charging will be described. During charging, the fuel material 12 reacts with hydrogen gas to produce water vapor and becomes a pure metal, the fuel electrode 18c reduces the water vapor to hydrogen gas, the solid oxide film 18a conducts oxygen ions, and the air electrode 18b oxidizes the oxygen ions to oxygen and releases it into the air.

[0020] Next, the state of the metal-air battery of the present invention during discharge will be described. During discharge, the air electrode 18b reduces oxygen in the air to oxygen ions, the solid oxide film 18a conducts the oxygen ions, the fuel electrode 18c oxidizes hydrogen gas to water vapor, and the fuel material 12 reacts with the water vapor to produce hydrogen gas and becomes an oxide itself.

[0021] Next, the effect of gravity on the metal-air battery of the present invention will be described. When the flat fuel cell cells 18 are arranged vertically, it is necessary to prevent the assembly 30 (if it is liquid rather than solid) from moving downward due to gravity. On the other hand, when the flat fuel cell cells 18 are arranged horizontally, gravity tends to cause hydrogen gas, water vapor, and nitrogen to gather from the top, and over a long period of time, the gas molecules gradually separate into layers. Therefore, in order to supply hydrogen gas to the fuel material 12 during charging and water vapor during discharging, and to supply water vapor during charging and hydrogen gas to the fuel cell cells 18 during discharging, it is preferable that the vertical lengths of the first internal space 14 and the second internal space 16 be as short as possible. Furthermore, it is preferable that the first internal space 14 and the second internal space 16 be arranged at the same vertical position (height) as much as possible. Because of the generation of pipe resistance, the flow path 32 is preferably as wide and short as possible, and is preferably arranged horizontally without tilting. Furthermore, if the gas temperature within each space is not uniform, convection is likely to occur. Specifically, when the heater is placed above, convection is likely to occur only in the gas above, but when the heater is placed below, convection is likely to occur not only in the gas above but also in the entire gas. The metal-air battery of the present invention is basically constructed as described above.

[0022] The metal-air battery of the present invention has been described in detail above, but the present invention is not limited to the above description, and various improvements and modifications may be made without departing from the spirit and scope of the present invention. [Industrial Applicability]

[0023] The metal-air battery of the present invention has the effect of shortening the apparent charging time, and is therefore industrially useful. [Explanation of symbols]

[0024] 10 Metal-air battery 12 Fuel material body 14 1st interior space 16 Second interior space 18 Fuel Cell 18a Solid oxide film 18b Air electrode 18c fuel electrode 20 Cooling gas introduction device 20a Nitrogen gas bottle 20b water container 20c water 22 Fuel container 24 First covering 24a 1st covering (after replacement) 24b 1st covering (before replacement) 26 Main container 28 Second covering 30 zygote 32 Flow path 34 Flow path opening and closing device 40 Fuel Exchange System 42 Mobile 44 Lifting device

Claims

1. A fuel substance that reacts with water vapor to produce hydrogen gas and becomes an oxide itself; a first internal space in which the fuel material is hermetically contained; a second internal space provided with a flat fuel cell unit, the fuel cell unit having, on one surface of an oxygen ion-conducting solid oxide film, an air electrode that reduces oxygen in the air to oxygen ions during discharge, and on the other surface of the solid oxide film, an anode that oxidizes hydrogen gas to water vapor by the oxygen ions during discharge; a flow path that connects the first internal space and the second internal space, A metal-air battery in which the fuel container forming the first internal space is detachable from the main body container forming the second internal space midway along the flow path.

2. A fuel substance that reacts with water vapor to produce hydrogen gas and becomes an oxide itself; a first internal space in which the fuel material is hermetically contained; a second internal space provided with a flat fuel cell unit, the fuel cell unit having, on one surface of an oxygen ion-conducting solid oxide film, an air electrode that reduces oxygen in the air to oxygen ions during discharge, and on the other surface of the solid oxide film, an anode that oxidizes hydrogen gas to water vapor by the oxygen ions during discharge; a cooling gas introduction device that introduces and exhausts a cooling gas into the first internal space, A metal-air battery in which the fuel container forming the first internal space is detachable from the main body container forming the second internal space.

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