Regeneration device for regenerating used fuel of metal-fueled fuel cell, regeneration method, and fuel cell including regeneration device

Abstract

The invention provides a fuel regeneration device capable of preventing short circuit caused by increase of metal volume. This regeneration device is used for regenerating a metal oxide-containing fuel of a fuel cell using a metal as a fuel, and is provided with: a container configured so as to be able to accommodate the metal oxide-containing fuel; the container includes: an electrode configured so as to be able to apply a current to the fuel to reduce the metal oxide to a metal; and a crushing unit configured so as to be able to mechanically crush at least a portion of the reduced metal generated on the negative electrode surface of the electrode.

Description

Technical Field

[0001] The present invention relates to a regeneration device for regenerating used fuel of a fuel cell using metal as fuel, a regeneration method and a fuel cell comprising the regeneration device. Background Art

[0002] With the popularization and progress of mobile phones, electric vehicles, etc. in recent years, it is expected that the battery used as the power source thereof will have a high capacity. In this case, the zinc-air battery has a high energy density and is a high-capacity battery superior to the currently common lithium-ion battery because it can be charged and discharged by utilizing oxygen in the atmosphere as the positive electrode active material at the positive electrode (air electrode) to perform the redox reaction of the oxygen and on the other hand, performing the redox reaction of the zinc constituting the negative electrode at the negative electrode.

[0003] Zinc-air batteries as primary batteries have been put into practical use and are now available on the market. Figure 1 As shown in Figure 1, it has a very high energy density compared to other battery systems. Therefore, many studies are being conducted to make zinc-air batteries secondary batteries. In particular, large-scale research has been carried out in the past 10 years as a national project in Japan, centered on universities.

[0004] The charge and discharge mechanism of the zinc-air battery is represented by the following equations (1) and (2). That is, the zinc-air battery is charged and discharged as follows: zinc passes through zinc acid (Zn(OH)4 in a quasi-discharge state) 2- ) to become zinc oxide for discharge, and the reverse reaction for charging.

[0005] (number 1)

[0006]

[0007] For example, Patent Document 1 shows an example of a battery using zinc for the negative electrode and nickel for the positive electrode. In Patent Document 1, in order to prevent a short circuit caused by zinc dendrites, it is proposed to increase the distance between electrodes and stir the electrolyte in the battery because the concentration gradient of zinc acid in the electrolyte is easily formed in the empty space after the distance between electrodes is increased.

[0008] In addition, Patent Document 2 proposes a secondary battery comprising: a second electrode arranged opposite to a first electrode and having a surface area larger than the opposing surface of the first electrode; and an electrode position changing device, and the secondary battery also comprises a removal device for scraping off dendrites generated in the second electrode.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent No. 6694955

[0012] Patent Document 2: Japanese Patent Application Publication No. 2013-225410 Summary of the invention

[0013] Technical problem to be solved by the invention

[0014] However, the research on zinc-air secondary batteries has not been smooth. The main reasons for this are: when the discharged zinc oxide or zinc acid is charged, the volume of the generated zinc increases, and the zinc grows to the counter electrode and causes a short circuit between the counter electrode; and therefore, a large amount of zinc cannot be carried in the battery. In the prior art such as Patent Document 1, although attempts are made to increase the distance between electrodes to suppress short circuits, they are still insufficient. Figure 2 FIG. 2 shows a photograph of the appearance of zinc that has expanded in volume from an initial thickness of 0.5 mm to 2 mm due to charge and discharge.

[0015] Thus, when using a fuel cell including a metal air battery such as a zinc air battery as a secondary battery, in order to prevent a short circuit caused by an increase in the volume of the metal, it is necessary to limit the amount of metal such as zinc loaded in the battery, making it difficult to unleash the potential of metals such as zinc and achieve high energy density.

[0016] Furthermore, in the prior art such as Patent Document 2, it is difficult to miniaturize the secondary battery because it is necessary to move the device at the installation position and scrape off the dendrites generated in the second electrode while moving the second electrode having a large surface area.

[0017] Therefore, in order to use a fuel cell using a metal such as zinc as a secondary battery with a high energy density, a small fuel regeneration device that can prevent a short circuit caused by an increase in the volume of the metal is required.

[0018] Solutions for solving technical problems

[0019] The gist of the present invention is as follows.

[0020] (1) A regeneration device for regenerating used fuel of a fuel cell using a metal as a fuel, comprising a container configured to accommodate the used fuel;

[0021] The used fuel contains a metal compound as a metal oxide, a metal hydroxide, or a combination thereof;

[0022] The aforementioned container contains:

[0023] an electrode configured to apply an electric current to the used fuel to reduce the metal compound to a metal; and

[0024] The crushing unit is configured to mechanically crush at least a portion of the reduced metal generated on the surface of the negative electrode in the electrode.

[0025] (2) The regeneration device according to (1) above, wherein:

[0026] The container comprises a first container and a second container connected to the first container;

[0027] The second container includes the electrode and the crushing portion.

[0028] (3) The regeneration device according to the above (2), wherein the second container is located below the first container.

[0029] (4) The regeneration device according to any one of (1) to (3) above, further comprising a third container configured to accommodate the fuel regenerated by the reduction process and the crushing process.

[0030] (5) The regeneration device according to the above (4), wherein the third container is located below the aforementioned container.

[0031] (6) A fuel cell comprising the regeneration device according to any one of (1) to (5) above and a discharge unit, and using the metal as a fuel.

[0032] (7) A fuel cell as described in (6) above, comprising a positive electrode for charging, a negative electrode for both charging and discharging, and a positive electrode for discharging;

[0033] The aforementioned positive electrode for charging and the aforementioned negative electrode for both charging and discharging constitute the aforementioned electrodes;

[0034] The discharge positive electrode and the charge-discharge negative electrode constitute the discharge section.

[0035] (8) The fuel cell according to (6) above, comprising a charging positive electrode, a charging negative electrode, a discharging positive electrode, and a discharging negative electrode; and

[0036] The aforementioned positive electrode for charging and the aforementioned negative electrode for charging constitute the aforementioned electrodes;

[0037] The discharge positive electrode and the discharge negative electrode constitute the discharge section.

[0038] (9) The regeneration device according to any one of (1) to (5) above, wherein the fuel cell is a metal-air battery, a metal flow battery, or a metal slurry fuel cell.

[0039] (10) The fuel cell according to any one of (6) to (8) above, wherein the fuel cell is a metal-air battery, a metal flow battery, or a metal slurry fuel cell.

[0040] (11) A regeneration method for regenerating used fuel in a fuel cell using a metal as fuel;

[0041] The used fuel contains a metal compound as a metal oxide, a metal hydroxide, or a combination thereof;

[0042] The aforementioned regeneration method comprises:

[0043] Receive the used fuel in a container;

[0044] performing a reduction treatment in which an electric current is applied to the spent fuel using an electrode to reduce the metal compound to a metal;

[0045] At least a portion of the reduced metal generated on the surface of the negative electrode in the electrode is subjected to mechanical crushing to regenerate the used fuel.

[0046] (12) The regeneration method according to (11) above, wherein

[0047] The aforementioned fuel cell using metal as fuel has a box-type anode unit;

[0048] Accommodating the used fuel in the container includes: taking out the used fuel from the cartridge anode unit and accommodating the used fuel in the container.

[0049] (13) The regeneration method according to (11) or (12) above, comprising:

[0050] Taking out the regenerated fuel from the container; and

[0051] The taken-out regenerated fuel is used as fuel for the fuel cell.

[0052] Effects of the Invention

[0053] According to the present invention, a small-sized fuel regeneration device capable of preventing a short circuit caused by an increase in metal volume can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a graph showing the relationship between the gravimetric energy density and volumetric energy density of various batteries.

[0055] Figure 2 This is a photo of the appearance of zinc that has expanded from an initial thickness of 0.5 mm to 2 mm due to repeated charge and discharge.

[0056] Figure 3This is a schematic cross-sectional view of an example of the regeneration device.

[0057] Figure 4 It is a schematic cross-sectional view of another example of the regeneration device.

[0058] Figure 5 It is a schematic cross-sectional view of another example of the regeneration device.

[0059] Figure 6 It is a schematic diagram of the present device including a first container and a second container.

[0060] Figure 7 This is a schematic diagram of a metal-air battery having a three-electrode system including the present regeneration device.

[0061] Figure 8 It means relative to the input Figure 7 Graph of the charge and discharge characteristics of zinc oxide metal-air batteries.

[0062] Fig. 9 This is a schematic diagram of a metal-air battery having a four-electrode system including the present regeneration device.

[0063] Fig.10 It is a schematic diagram of a metal-air battery of a comparative example.

[0064] Fig.11 This is a graph of discharge voltage obtained from a metal-air battery equipped with the present regeneration device.

[0065] Fig.12 This is a schematic diagram of a metal-air battery having a four-electrode system including the present regeneration device.

[0066] Fig.13 It is a schematic diagram of the regeneration device and the fuel cell (discharge cell unit) prepared separately.

[0067] Fig.14 It is a schematic diagram of the regeneration device and the fuel cell (discharge cell unit) prepared separately.

[0068] Fig.15 It is a schematic cross-sectional view of a rotating barrel having a negative electrode for charging. DETAILED DESCRIPTION

[0069] The object of the present disclosure is a regeneration device (hereinafter also referred to as the present device), which is used to regenerate used fuel of a fuel cell using metal as fuel, and has a container configured to accommodate the aforementioned used fuel, wherein the aforementioned used fuel contains a metal compound that is a metal oxide, a metal hydroxide, or a combination thereof, and the aforementioned container includes: a pair of electrodes, which are configured to apply an electric current to the aforementioned used fuel to reduce the aforementioned metal compound to a metal; and a crushing part, which is configured to mechanically crush at least a portion of the aforementioned reduced metal generated on the surface of the negative electrode in the aforementioned pair of electrodes.

[0070] The inventors conducted in-depth research and found that the density of the metal (hereinafter also referred to as metal dendrites, precipitated metal, etc., such as zinc) generated when the metal compound (such as zinc oxide or zinc acid) in the used fuel is reduced (charged) is sparse and the volume is large, but by crushing the metal generated by the reduction treatment, the density can be increased and the volume can be reduced, thereby completing the present device. According to the present invention, the volume of the metal generated (precipitated) by the reduction treatment can be reduced, so that the short circuit caused by the increase in the metal volume can be prevented, and a large amount of metal fuel can be loaded in a small fuel cell.

[0071] Figure 3 , a schematic cross-sectional view of an example of the present device 100 is shown. The present device 100 includes a container 10. The container 10 is configured to accommodate the used fuel 1. The container 10 includes a pair of electrodes 20 and a crushing unit 30. The container 10 may include an inlet for accommodating the used fuel 1. The container 10 may also include a discharge unit for discharging the regenerated fuel 2 after the reduction treatment and the crushing treatment.

[0072] The introduction of the used fuel 1 and the discharge of the regenerated fuel 2 may be performed using a pump, but preferably by gravity. The introduction portion is provided on the upper surface or side of the container 10, and the discharge portion is provided on the side or bottom of the container 10, so that the introduction of the used fuel 1 and the discharge of the regenerated fuel 2 can be performed by gravity. When the introduction of the used fuel 1 and the discharge of the regenerated fuel 2 are performed by gravity, the introduction portion may be an opening, an openable and closable cover, a valve, etc., and the discharge portion may be an openable and closable cover, a valve, etc. The valve may be a gate valve, a globe valve, a ball valve, a butterfly valve, a diaphragm valve, a solenoid valve, etc.

[0073] The material of the container 10 is not particularly limited as long as it is chemically stable when in contact with the fuel, and may be alkali-resistant, such as acrylic, polyvinyl chloride, polypropylene, polystyrene, polyethylene, etc. In addition, the container 10 may also be a composite body in which an alkali-resistant coating is applied to the inner wall of a metal container.

[0074] In the present application specification, a fuel cell using metal as fuel (hereinafter, also referred to as a fuel cell) refers to a metal-air battery, a metal flow battery, or a metal slurry fuel cell. A metal-air battery is a battery that uses oxygen in the air as a positive electrode active material and a metal as a negative electrode active material. A metal flow battery, also known as a liquid flow metal-air battery, uses metal as a fuel (active material) and has a battery cell (cell) that is responsible for charging and discharging the battery and a storage unit for an energy storage material containing an electrolyte, each of which is independently connected by piping. A metal slurry fuel cell is a battery that uses a substance in which a metal fuel and an electrolyte are integrated and slurried as an energy source.

[0075] In the present application, the fuel may include, depending on the type of fuel cell, an electrolyte containing a metal active substance, a fuel containing a metal slurry, etc. When the fuel cell is used (discharged), the metal is oxidized to generate a metal compound (hereinafter collectively referred to as a metal compound) as a metal oxide, a metal hydroxide, or a combination thereof. The metal compound may be an ion. In the present application, regeneration is a concept that includes charging, for example, the regeneration of a metal fuel, the charging of an electrolyte containing a metal as an active substance, etc. The metal may be a metal that can be precipitated in an aqueous plating, such as zinc, copper, tin, bismuth, phosphine, nickel, lead, etc., preferably zinc.

[0076] The electrode 20 is configured to reduce the oxidized metal in the used fuel 1. The electrode 20 includes a pair of electrodes, and a portion of the electrode 20 is configured to be immersed in the used fuel 1. By applying electric energy to the electrode 20, the metal compound in the used fuel 1 can be supplied with electrons for reduction treatment, that is, charging can be performed. The electrode 20 is a cathode electrode, and is not particularly limited as long as it is a conductor that is stable in an alkaline electrolyte. For example, it can be composed of metals such as nickel, iron, titanium, platinum, gold, carbon, etc. The electric energy applied to the electrode 20 is preferably renewable energy.

[0077] This device can be used, for example, as a device combined with a stationary battery, and can convert surplus power into metals such as zinc. In the past, surplus power was converted into gases such as hydrogen, but according to this device, surplus power can be converted into metals such as zinc that are easier to handle than gases. The above-mentioned surplus power refers to the surplus power of the difference between the load and the power consumption of the load when the power generation from renewable energy sources that vary due to weather, etc. exceeds the power consumed by the load. When the load is connected to both the system power and the renewable energy power generation device, if surplus power is generated, it will be sold to the system side, which will cause a burden on the system power side as a reverse flow, so it is preferable to avoid the generation of reverse flow as much as possible; according to this device, surplus power can be efficiently converted into metals such as zinc.

[0078] The crushing section 30 is configured to mechanically crush at least a portion of the reduced metal generated on the surface of the electrode 20. In the present application, mechanical crushing refers to breaking up the metal dendrites generated on the surface of the electrode 20 to make it a reusable metal fuel for the fuel cell. The form of the reusable metal fuel is not particularly limited, and the metal may be in the form of powder, granules, blocks, plates, films, blocks, etc. In the present application, the so-called crushing preferably refers to pulverization, fragmentation, or a combination thereof.

[0079] In the present application, mechanical means that the crushing unit 30 applies force to the metal dendrites directly or indirectly. That is, in the present application, crushing means that the crushing unit 30 is included in contact with or non-contact with the metal dendrites to perform mechanical crushing. Contact mechanical crushing means that the crushing unit 30 contacts the metal dendrites and directly applies mechanical action to them to crush them. Non-contact mechanical crushing means that the crushing unit 30 does not contact the metal dendrites but indirectly applies mechanical action to them to crush them, such as using ultrasound and crushing through a medium such as liquid as described below. The crushing unit 30 can be composed of one or more crushers and the like. When the fuel is regenerated (charged), metals such as zinc with sparse density will be precipitated on the negative electrode of the electrode 20, but they can be mechanically crushed by the crushing unit 30. The crushing unit 30 is configured to be able to crush low-density metals generated by regeneration (charging), and can be composed of metals, ceramics, plastics, etc.

[0080] The crushing part 30 may be configured to slide on the negative electrode surface of the electrode 20 and crush the metal deposited on the electrode surface; or may be configured to have a specified distance from the electrode 20 surface and crush the metal grown from the electrode surface to a specified thickness.

[0081] The structure of the crushing section 30 is not particularly limited as long as it can crush the sparsely-densed zinc and other metals on the electrode 20 deposited during regeneration (charging). For example, it can be: a scraper, a stirrer, a stirring blade and other agitators, a mechanism for shaking the entire device, a mechanism for shaking the electrode, a mechanism for applying ultrasonic waves, a compression mechanism, etc. In the above-mentioned examples of the crushing section 30, examples of mechanical crushing in contact with the deposited metal are: a scraper, a stirrer, a stirring blade and other agitators, a rotating barrel, and a compression mechanism; examples of mechanical crushing without contact with the deposited metal are: a mechanism for shaking the entire device, a mechanism for shaking the electrode, and a mechanism for applying ultrasonic waves. The above examples are not intended to limit contact or non-contact. For example, in the case of a stirring blade, not only can the stirring blade be brought into contact with the metal dendrites for crushing, but the metal dendrites can also be crushed by the water flow generated by the stirring blade when the stirring blade is in a state of non-contact with the metal dendrites.

[0082] The rotating barrel may be provided with a mesh, hole, or combination thereof of a size that allows the electrolyte to pass through the inside and outside of the rotating barrel and the medium disposed inside the rotating barrel cannot pass through. The crushed metal may also pass through the above mesh, hole, or combination thereof, but the rotating barrel may be provided with a mesh, hole, or combination thereof of a size that prevents the crushed metal from passing through. The rotating barrel may also have a negative electrode for charging that passes from the rotating shaft or its vicinity to the inside. Fig.15 As shown in the example, the negative electrode 22 for charging can be arranged inside the rotating barrel from the rotating axis or its vicinity so as not to rotate together with the rotating barrel as the crushing part 30, and is preferably arranged vertically downward in a manner of contacting the medium 32. The negative electrode 22 for charging that passes through the rotating barrel from the rotating axis or its vicinity and is arranged inside the rotating barrel can be a metal wire, a metal foil, a metal mesh, etc.

[0083] The material of the rotating barrel is not particularly limited as long as it is non-conductive and has a strength that allows a medium to be placed inside and rotated, and may be made of resin, ceramic, or a composite thereof. The rotating barrel is preferably made of an alkali-resistant resin, such as polypropylene, polyvinyl chloride, polyvinylidene chloride, polyethylene, polystyrene, phenol, or the like. The shape of the rotating barrel is not particularly limited, and may be cylindrical, polygonal, or a combination thereof when viewed in a direction parallel to the rotation axis.

[0084] The rotating barrel has a medium for crushing the precipitated metal inside. The material of the medium can be composed of a material having a strength capable of crushing the precipitated metal and at least a surface that is alkali-resistant and conductive. The medium can be, for example, a metal medium, a medium having a metal film such as copper formed by chemical plating on the surface of a resin such as nylon, etc. The conductive material constituting at least the surface of the medium can be the same metal as the collector that can be used for the negative electrode for charging, preferably a metal that does not produce hydrogen when in contact with the metal fuel. When the metal fuel is zinc, the conductive material constituting at least the surface of the medium can be, for example, Cu, In, Sn, Bi, or Pb. The medium can have any three-dimensional shape such as a sphere, a cylinder, a cone, a polyhedron, etc., preferably a sphere. The size of the medium is not particularly limited, for example, it has a diameter of 0.1 to 10 mm, 0.5 to 5 mm, or 1 to 3 mm.

[0085] If the metal compound is regenerated (charged) while the rotating barrel is rotating, metal dendrites will precipitate on the surface of the charging negative electrode of the rotating barrel, and metal dendrites will also precipitate on the surface of the medium. As the rotating barrel rotates, the medium moves, so that collisions between the charging negative electrode and the medium and between the mediums occur, which can break up the metal dendrites precipitated on the surface of the charging negative electrode, and can also break up the metal dendrites precipitated on the surface of the medium. The broken metal dendrites can be accumulated in the lower part of the rotating barrel. If the broken metal dendrites are of a size that can pass through the mesh or holes of the rotating barrel, they can also be accumulated in the lower part of the container. The broken metal remaining in the rotating barrel, the broken metal accumulated in the lower part of the container, or both can be used as regenerated fuel.

[0086] At least a portion of the metal dendrites precipitated on the surface of the medium is crushed and compressed by the collision with the negative electrode for charging or the collision between the mediums, and a film can be formed on the surface of the medium. That is, the metal dendrites precipitated on the surface of the medium can fall off the medium due to crushing as described above, or can be crushed and compressed due to the collision between the mediums and remain on the surface of the medium. The medium with crushed and compressed metal on the surface can be used as a regenerated fuel together with the crushed metal accumulated at the bottom of the rotating barrel, the bottom of the container, or a combination thereof, or alone.

[0087] In this way, the medium and the rotating barrel function as a crushing unit 30, which can not only crush the metal deposited on the surface of the negative electrode for charging, but also crush the metal deposited on the surface of the medium and use it as a regenerated fuel; further, the medium having a film of deposited metal on the surface can also be used as a regenerated fuel.

[0088] When the crushed metal accumulated at the bottom of the rotating drum and the medium having a film of precipitated metal on the surface are used as regeneration fuel, it is preferred to accumulate the crushed metal in the rotating drum. In this case, the crushed metal after reduction treatment can be recovered together with the medium as regeneration fuel, which is convenient.

[0089] When only crushed metal is used as regeneration fuel, or when only medium having a metal film deposited on the surface is used as regeneration fuel, it is preferred to accumulate crushed metal at the bottom of the container outside the rotating drum. In this case, the crushed metal and medium after reduction treatment can be recovered as regeneration fuel respectively, which is convenient.

[0090] When the reduced metal is used as a regenerative fuel, the solution of the used fuel recovered may be used together with the reduced metal as the regenerative fuel, or only the reduced metal may be recovered and mixed with a newly prepared solution and used as the regenerative fuel. For example, when crushed metal is used as a regenerative fuel, the solution of the used fuel recovered may be used together with the crushed metal as the regenerative fuel, or only the crushed metal may be recovered and mixed with a newly prepared solution and used as the regenerative fuel. For example, when a medium having a film of precipitated metal on its surface is used as a regenerative fuel, the solution of the used fuel recovered may be used together with the medium as the regenerative fuel, or only the medium may be recovered and mixed with a newly prepared solution and used as the regenerative fuel.

[0091] The compression mechanism is, for example, a pressurizing mechanism having a pressurizing portion. There is no particular limitation on the material of the pressurizing mechanism as long as it is non-conductive and has the strength to crush metal dendrites by pressurization and is alkali-resistant. For example, it may be made of resins such as polytetrafluoroethylene (PTFE), ceramics, or a composite thereof, or a material obtained by coating the metal surface with resin or ceramics. The shape of the pressurizing portion is not particularly limited and may be plate-shaped. By crushing the metal dendrites by pressurization, the metal dendrites can be compressed and densified into a plate shape while being crushed, which is preferred from the viewpoint of the easy handling and energy density of the regenerated fuel. When the plate-shaped metal is used as the regenerated fuel, a solution of the used fuel recovered together with the plate-shaped metal may be used as the regenerated fuel, or only the plate-shaped metal may be recovered and mixed with a new solution prepared separately and used as the regenerated fuel.

[0092] The mechanism for applying ultrasonic waves is, for example, an ultrasonic homogenizer. The ultrasonic homogenizer is composed of an oscillator and a vibrator. The output from the oscillator is converted into vibration by a vibrating element inside the vibrator, so that the chip at the front end of the vibrator generates longitudinal vibrations of, for example, about 20,000 times per second. This vibration generates bubbles called cavitations in the liquid. When the bubbles collapse, they can impact the surrounding particles and break the metal dendrites.

[0093] The crushing unit 30 may continuously perform the crushing action or may perform the crushing action at a specified time. The specified time may be a fixed time interval or an arbitrary time. Preferably, the crushing unit 30 may be equipped with a sensor for detecting the amount of metal precipitation (growth) from the negative electrode surface of the electrode 20 toward the counter electrode, and the crushing action is started when the sensor detects the precipitation of the specified thickness, and the crushing action is stopped when the sensor does not detect the precipitation of the specified thickness.

[0094] The sensor may be, for example, a light sensor. The device 100 may include a control unit and perform the above control. The control unit may include: a communication unit for communicating with the sensor and the crushing unit 30, a storage unit for storing data received by the communication unit, and a processing unit for determining whether the precipitation amount is above a specified thickness based on the data stored in the storage unit.

[0095] like Figure 3 As shown in the example, the container 10 may include a portion for accommodating the used fuel 1 introduced from the introduction portion 16 and a portion having the electrode 20 and the crushing portion 30 and accommodating the used fuel 1 without separation. Figure 3 The structure can be expected to be miniaturized.

[0096] In another method, such as Figure 4 As shown in the example, the container 10 may also include a first receiving portion 101 at the upper portion for receiving the used fuel 1 introduced from the introduction portion 16, and a second receiving portion 102 at the lower portion for receiving the regenerated fuel 2 after regenerating the used fuel 1 and having an electrode 20 and a crushing portion 30. Figure 4 The structure can be expected to be miniaturized.

[0097] In another method, such as Figure 5 As shown in the example, the container 10 also includes a partition 15, and can be divided by the partition 15 to include a first receiving portion 101 for receiving the used fuel 1 introduced from the introduction portion 16, and a second receiving portion 102 including an electrode 20 and a crushing portion 30 for receiving the regenerated fuel 2 after the used fuel 1 is regenerated. Figure 5 The structure can also obtain a relatively small and simple regeneration device.

[0098] The partition 15 may be a plate or a net having holes through which the used fuel 1 can pass, or may be a plate through which the used fuel 1 cannot pass. In the case where the partition 15 is a plate through which the used fuel 1 cannot pass, Figure 5 As shown, the vertical length of the partition 15 is configured to be shorter than the depth of the used fuel 1 so that the used fuel 1 is separated between the first receiving section 101 and the second receiving section 102 at a deep position, and the used fuel 1 can diffuse between the first receiving section 101 and the second receiving section 102 at a shallow position.

[0099] Preferably, the container 10 includes a first container 11 and a second container 12 connected to the first container 11 , and the second container 12 includes an electrode 20 and a crushing unit 30 .

[0100] Figure 6Schematic diagram of the present device 100 including a first container 11 and a second container 12 is shown in FIG. The first container 11 is configured to accommodate the used fuel 1. The first container 11 may include an inlet 16 for accommodating the used fuel 1. The configuration of the inlet 16 may be applicable to the above configuration. The first container 11 includes a connection portion 14 connected to the second container 12. Figure 6 In the configuration shown, a relatively small and simple-structured regeneration device can also be obtained.

[0101] The second container 12 is connected to the first container 11 via the connection portion 14, and is configured to accommodate the used fuel 1. The second container 12 includes an electrode 20 and a crushing portion 30. The configuration of the electrode 20 and the crushing portion 30 can be applied to the above-mentioned configuration. The connection portion 14 is configured so that at least a portion of the used fuel 1 introduced into the first container 11 can move toward the second container 12 in the direction indicated by the arrow. The second container 12 may also include a replenishing port for replenishing water, an electrolyte, and the like, such as an alkaline solution.

[0102] The method of moving the used fuel 1 from the first container 11 to the second container 12 via the connection portion 14 is not particularly limited, and the used fuel 1 may be moved using a pump, or the second container 12 may be located below the first container 11 and the used fuel 1 may be moved from the first container 11 to the second container 12 using weight.

[0103] In another method, such as Figure 6 As shown in the example, the first container 11 and the second container 12 may be arranged in a substantially horizontal position, and the used fuel 1 may be moved to the second container 12 via the connection portion 14 arranged at a predetermined position above the bottom of the first container 11. When the first container 11 and the second container 12 are connected via the connection portion 14 at a predetermined position above the bottom of the first container 11, the used fuel 1 at a shallow position can be moved to the second container 12 while the sediment of foreign matter contained in the used fuel 1 is left in the first container 11 to prevent it from moving to the second container 12, so that only the fuel containing the above-mentioned metal compound and / or the above-mentioned metal compound ions required for charging can be moved to the second container 12.

[0104] The fuel contained in the first container contains a large amount of oxidized metals, and the oxidized metals in the fuel contained in the second container are reduced, so that a concentration gradient of the oxidized metals is formed between the first container and the second container. Due to the concentration gradient, concentration diffusion occurs, and the oxidized metals in the fuel can move from the first container to the second container.

[0105] Preferably, the present device 100 further includes a third container 13 configured to accommodate the regenerated fuel 2 containing the metal that has been subjected to the reduction treatment and the crushing treatment. The regenerated fuel 2 containing the reduced and crushed metal can be recovered from the container 10 or the second container 12 to the third container 13. The third container 13 may also include a replenishing port for replenishing water or an electrolyte, such as an alkaline solution. The movement of the regenerated fuel 2 from the container 10 or the second container 12 to the third container 13 can be performed by any method, for example, by using a pump, but it is preferably moved to the third container 13 arranged below the container 10 or the second container 12 by gravity. Figure 6 An example is shown in which the regenerated fuel 2 is moved from the second container 12 to the third container 13 disposed below using gravity.

[0106] Preferably, the third container 13 is located below the container 10 or the container 12. Since the third container 13 is located below the container 10 or the container 12, the regenerated fuel 2 that has been reduced and crushed can be stored in the third container 13 from the container 10 or the container 12 by gravity.

[0107] The material of the first container 11 , the second container 12 , and the third container 13 is not particularly limited as long as it is chemically stable when in contact with the fuel, and may be the same material as the container 10 .

[0108] The regenerated fuel 2 after the reduction treatment and the crushing treatment is preferably recovered from the container 10 , the second container 12 , or the third container 13 to a transportable recovery container 40 . Figure 6 This shows an example of recovering the regenerated fuel 2 from the third container 13 to the recovery container 40. The recovery container 40 is preferably arranged below the container 10, the second container 12, or the third container 13, and the regenerated fuel 2 is recovered by gravity. The material of the recovery container 40 is not particularly limited as long as it can hold the regenerated fuel 2, and can be composed of the same material as the container 10.

[0109] The fuel contained in the metal-air battery, metal flow battery, or metal slurry fuel cell may be an aqueous solution containing a metal, or may be an electrolyte, for example, an aqueous alkaline aqueous solution.

[0110] The powder of the precipitated metal after the crushing process is not substantially in a dispersed state, and the particles of the precipitated metal can contact each other and have electrical conductivity. In a container, the powder of the precipitated metal after the crushing process is precipitated at the bottom, and the electrode is immersed in an aqueous solution, and the reduction treatment (electrodeposition) of the oxidized metal is carried out in this state.

[0111] The object of the present disclosure is also: a fuel cell using metal as fuel (hereinafter also referred to as the present fuel cell) having the above-mentioned regeneration device and a discharge unit. The present fuel cell can use the regeneration fuel regenerated by the regeneration device and discharge by the discharge unit. The discharge unit is preferably located below the regeneration device. By the discharge unit being located below the regeneration device, the fuel regenerated by the regeneration device can be moved to the discharge unit by its own weight using gravity.

[0112] like Figure 7 As illustrated, the fuel cell 300 is preferably a three-electrode system battery including a charging positive electrode 21, a charging and discharging negative electrode 22, 52, and a discharging positive electrode 51; the charging positive electrode 21 and the charging and discharging negative electrode 22 constitute the above-mentioned electrode 20; the discharging positive electrode 51 and the charging and discharging negative electrode 52 constitute the discharge part 200.

[0113] like Fig. 9 As shown, the fuel cell 400 is a four-electrode system battery including a charging positive electrode 21, a charging negative electrode 22, a discharging positive electrode 51, and a discharging negative electrode 52; the charging positive electrode 21 and the charging negative electrode 22 constitute the above-mentioned electrode 20; the discharging positive electrode 51 and the discharging negative electrode 52 constitute the discharging part 200. Figure 7 and Fig. 9 The illustrated configuration can provide a fuel cell having a small and simple structure and a high energy density.

[0114] The fuel cell may be a metal-air battery, a metal flow battery, or a metal slurry fuel cell.

[0115] The object of the present disclosure is also: a regeneration method (hereinafter also referred to as the present regeneration method), which is used to regenerate used fuel of a fuel cell using metal as fuel, wherein the used fuel contains a metal compound that is a metal oxide, a metal hydroxide, or a combination thereof, and the regeneration method comprises: accommodating the used fuel into a container; performing a reduction treatment of applying an electric current to the used fuel using an electrode to reduce the metal compound to a metal; and mechanically crushing at least a portion of the reduced metal generated on the negative electrode surface in the electrode to regenerate the used fuel.

[0116] The oxygen generated during regeneration (charging) can be effectively utilized by being placed in the discharge section (discharge cell) 200 .

[0117] In the regeneration method, preferably, the fuel cell using the metal as fuel has a cartridge-type anode unit, and storing the used fuel in the container includes: taking out the used fuel from the cartridge-type anode unit and storing it in the container.

[0118] The present regeneration method preferably includes taking out the regenerated fuel from the container 10 and using the taken out regenerated fuel as fuel for the fuel cell.

[0119] [Example]

[0120] (Reference Example 1) Evaluation of Metal-Air Battery Using Reduced Fuel

[0121] Production Figure 7 A fuel cell 300 as a metal-air battery of a three-electrode system is schematically shown in FIG. In the manufactured fuel cell 300, a positive electrode 21 for charging is provided in the upper section inside a cylindrical container 10 made of acrylic plastic with an inner diameter of 25 mm and a height of 25 mm, negative electrodes 22 and 52 for both charging and discharging are provided in the middle section, and a positive electrode 51 for discharging is provided in the lower section, and oxygen can be obtained from the positive electrode 51 for discharging. As a crushing section 30, a stirring blade (1-7124-02 three-one motor BL600 (AXEL) AS ONE) is arranged between the positive electrode 21 for charging in the upper section and the negative electrode 22 and 52 for both charging and discharging in the middle section. The fuel cell 300 is composed of a container 10, a regeneration device 100 including a positive electrode 21 for charging, a negative electrode 22 for both charging and discharging and a crushing section 30, and a discharge section 200 including a positive electrode 51 for discharging and a negative electrode 52 for both charging and discharging.

[0122] A nickel metal mesh having an opening in the center for passing the mixer of the crushing unit 30 was used as the upper charging positive electrode 21. A copper metal mesh was used as the charging and discharging negative electrodes 22 and 52. A nickel-plated SUS mesh was used as the lower discharging positive electrode 51.

[0123] Ketjen black: polytetrafluoroethylene (PTFE) aqueous dispersion (solid content concentration Nv 60%): water = 10: 1: 2 mass ratio is mixed, the mixture is placed in a polyethylene bag, and a roller press device adjusted to a roller gap (gap) of 0.5 mm is used to roll to obtain a flat slurry. The obtained flat slurry is rolled on a nickel-plated SUS grid used as the lower section of the discharge positive electrode 51 for integration, and then the other side (the lower side) is rolled and attached with a permeable PTFE water-repellent film (thickness 100μm, Gurley value (Gurley value) 18sec / 100mL), and the air electrode layer (oxygen reduction electrode) of the discharge positive electrode 51 (positive electrode collector) / catalyst layer / PTFE water-repellent film is made.

[0124] In the manufactured fuel cell 300, 25 g of a 3M potassium hydroxide aqueous solution containing 1 g of zinc oxide (particle size 0.3 μm) after discharge is added as an electrolyte from the charging positive electrode 21 of the metal grid, and is filled from the upper charging positive electrode 21 to the lower discharging positive electrode 51 through the charge and discharge negative electrodes 22 and 52.

[0125] exist Figure 7 In the upper two electrodes, the zinc oxide in the electrolyte is reduced (charged) to zinc, and the reduced zinc is used as a fuel to discharge at the lower two electrodes. When charging, the current flows from the negative electrode 22 in the middle to the positive electrode 21 for charging in the upper section, and when discharging, the current flows from the negative electrode 52 in the middle to the positive electrode 51 for discharging in the lower section.

[0126] Instead of the 3M potassium hydroxide aqueous solution containing 1g of zinc oxide, 6M and 9M potassium hydroxide aqueous solutions containing 2g and 3g of zinc oxide were introduced, respectively, and reduction treatment (charging) and discharge were performed in the same manner. In the charge and discharge test, a charge and discharge tester (HJ-1001SD8) manufactured by Hokuto Electric Co., Ltd. was used as a measuring device, and the charge capacity and discharge capacity based on the amount of zinc oxide were measured from the trends of the charge voltage and discharge voltage under the condition of a charge and discharge current of 100mA. Figure 8 Shown in the use Figure 7 A graph showing the charge and discharge characteristics of a three-electrode metal-air battery during charge and discharge.

[0127] Figure 8 Relative to the input Figure 7 The charge and discharge characteristics of the metal-air battery with 1g, 2g, and 3g of zinc oxide. When the amount of zinc oxide is 1g, the stacking thickness of zinc oxide is 2mm, and it shows a discharge capacity of 685mAh in 6.5 hours. When the amount of zinc oxide is 2g, the stacking thickness of zinc oxide is 4mm, and it shows a discharge capacity of 1316mAh in 13 hours. When the amount of zinc oxide is 3g, the stacking thickness of zinc oxide is 6mm, and it shows a discharge capacity of 1974mAh in 26.5 hours. In this way, the discharge capacity increases almost proportionally to the amount of zinc oxide. From this point of view, any amount of zinc oxide is fully regenerated, showing good charge and discharge characteristics as an air battery. However, as Figure 2 As shown, when the amount of zinc oxide is 3 g (deposited thickness is 6 mm), the thickness of zinc after charging is 20 mm.

[0128] (Example 1) Metal-air battery using regenerated fuel subjected to reduction and crushing

[0129] Production Fig. 9A fuel cell 400 as a metal-air battery of a four-electrode system is schematically shown in FIG. In the manufactured fuel cell 400, a charging positive electrode 21 and a charging negative electrode 22 are provided in the upper section inside a cylindrical container 10 made of acrylic plastic with an inner diameter of 25 mm and a height of 50 mm, and a discharge positive electrode 51 and a discharge negative electrode 52 are provided in the lower section, and oxygen can be obtained from the discharge positive electrode 51 side. As a crushing section 30, a stirring blade (1-7124-02 three-in-one motor BL600 (AXEL) Aswan) is arranged between the charging positive electrode 21 and the charging negative electrode 22 in the upper section. The fuel cell 400 is composed of a container 10, a regeneration device 100 including a charging positive electrode 21, a charging negative electrode 22 and a crushing section 30, and a discharge section 200 including a discharge positive electrode 51 and a discharge negative electrode 52.

[0130] A nickel metal mesh was used as the upper charging positive electrode 21. A copper metal mesh was used as the charging negative electrode 22 and the discharging negative electrode 52. A nickel-plated SUS mesh was used as the lower discharging positive electrode 51, and the air electrode layer (oxygen reduction electrode) of the discharging positive electrode 51 (positive electrode current collector) / catalyst layer / PTFE water-repellent film was prepared in the same manner as in Reference Example 1. Fig. 9 As shown, the discharge negative electrode 52 has a U-shaped cross section and an open top surface.

[0131] In the fuel cell 400 , 50 g of a 3M potassium hydroxide aqueous solution containing 2 g of zinc oxide (particle size 0.3 μm) after discharge is introduced as an electrolyte from the upper part and is filled from the charge positive electrode 21 and the charge negative electrode 22 to the discharge positive electrode 51 at the lower stage through the discharge negative electrode 52 .

[0132] While the stirring blade of the crushing part 30 is rotated at a rotation speed of 10 rpm, a current of 100 mA is passed between the upper charging positive electrode 21 and the charging negative electrode 22 to reduce the zinc oxide, precipitate zinc equivalent to 1 g (equivalent to 820 mAh), and the precipitated zinc is crushed by the stirring blade. The crushed zinc is accumulated inside the "コ"-shaped discharge negative electrode 52 of the lower stage.

[0133] The crushed zinc deposited on the discharge negative electrode 52 was used as a regeneration fuel, and a current of 20 mA was passed between the discharge positive electrode 51 and the discharge negative electrode 52 to perform discharge. As a result, the following was obtained: Fig.11 The discharge voltage shown gives a capacity of about 760 mAh.

[0134] (Example 2)

[0135] The same method as in Example 1 was used to prepare the crushing unit 30 except that an ultrasonic homogenizer (Yamato Scientific Ultrasonic Homogenizer, LUH150) was used instead of the stirring blade. Fig.12 A fuel cell 400 as a metal-air battery of a four-electrode system is schematically shown in FIG. The front end of the ultrasonic homogenizer on the negative electrode 22 side for charging is arranged with a gap of about 2 mm from the negative electrode 22 for charging.

[0136] In the fuel cell 400 , 50 g of a 3M potassium hydroxide aqueous solution containing 2 g of zinc oxide (particle size 0.3 μm) after discharge is introduced as an electrolyte from the upper part and is filled from the charge positive electrode 21 and the charge negative electrode 22 to the discharge positive electrode 51 at the lower stage through the discharge negative electrode 52 .

[0137] The ultrasonic homogenizer was vibrated at 20kHz to generate ultrasonic waves at an output power of 50W, and a current of 100mA was passed between the upper charging positive electrode 21 and the charging negative electrode 22 to reduce zinc oxide, precipitate zinc equivalent to 1g (equivalent to 820mAh), and the precipitated zinc was crushed by the ultrasonic waves emitted by the ultrasonic homogenizer. The crushed zinc was deposited inside the "コ"-shaped discharge negative electrode 52 at the lower stage.

[0138] Zinc deposited on the discharge negative electrode 52 was used as a regeneration fuel, and a current of 20 mA was passed between the discharge positive electrode 51 and the discharge negative electrode 52 to perform discharge. As a result, the same discharge voltage and capacity as those in Example 1 were obtained.

[0139] (Example 3)

[0140] like Fig.13 As schematically shown in FIG. 1 , a regeneration device 100 and a fuel cell (discharge cell) 500 are prepared respectively. In the regeneration device 100, a charging negative electrode 22 is provided at the lower part of a cylindrical container 10 made of acrylic plastic with an inner diameter of 25 mm and a height of 25 mm, and a cylindrical charging positive electrode 21 is provided at the upper part. As a crushing part 30, a pressurizing mechanism having a cylindrical pressurizing part made of polytetrafluoroethylene (PTFE) with a diameter of 23 mm is provided to pressurize and crush zinc dendrites precipitated from the surface of the charging negative electrode 22 to the charging positive electrode 21 from the upper part.

[0141] A nickel metal mesh having an opening in the center for passing a shaft of a pressurizing unit supporting a pressurizing mechanism was used as the upper charging positive electrode 21. A copper metal mesh was used as the charging negative electrode 22.

[0142] In the fuel cell 500, a discharge positive electrode 51 is provided at the bottom of a cylindrical container 10 made of acrylic plastic with an inner diameter of 25 mm and a height of 25 mm, and a discharge negative electrode 52 is provided at the top thereof, and has a structure capable of obtaining oxygen from the discharge positive electrode 51 side. As the discharge positive electrode 51, a nickel-plated SUS mesh is used, and the discharge positive electrode 51 (positive electrode collector) / catalyst layer / PTFE water-repellent film air electrode layer (oxygen reduction electrode) is prepared in the same manner as in Reference Example 1. Fig.13 As shown, the discharge negative electrode 52 has a U-shaped cross section and an open top surface.

[0143] 25 g of a 3M potassium hydroxide aqueous solution containing 1 g of zinc oxide (particle size 0.3 μm) after discharge was added as an electrolyte from the upper portion of the regeneration device 100 , and filled from the charge positive electrode 21 to the charge negative electrode 22 .

[0144] A current of 100 mA was passed between the positive electrode 21 for charging and the negative electrode 22 for charging, and the zinc oxide was reduced, and zinc equivalent to 1 g (equivalent to 820 mAh) was precipitated on the negative electrode 22 for charging. The pressurizing part was pressed down, and the zinc precipitated on the negative electrode 22 for charging was crushed and densified, and a plate-shaped regenerated fuel 3 of 1 mm thick composed of zinc was obtained on the negative electrode 22 for charging.

[0145] The obtained plate-like zinc was taken out from the regeneration device 100 and placed on the discharge negative electrode 52 of the fuel cell 500. 25 g of a 3M potassium hydroxide aqueous solution was added to fill the discharge positive electrode 51 to the discharge negative electrode 52, and a current of 20 mA was passed between the discharge positive electrode 51 and the discharge negative electrode 52 to discharge, resulting in the same discharge voltage and capacity as in Example 1.

[0146] (Example 4)

[0147] like Fig.14 As schematically shown in FIG. 1 , a regeneration device 100 and a fuel cell (discharging battery unit) 500 are prepared separately. In the regeneration device 100, a cylindrical container 10 made of acrylic plastic with an inner diameter of 25 mm and a height of 25 mm is provided with a rotating barrel as a crushing part 30 at the bottom, and a cylindrical charging positive electrode 21 is provided at the top. The rotating barrel has an inner diameter of 25 mm and is composed of a mesh of polypropylene resin. A copper ball 25 g with a diameter of 2 mm is arranged in the rotating barrel as a medium 32.

[0148] The regeneration device 100 also includes a copper wire with a diameter of 3 mm that passes through the rotating shaft of the rotating barrel to the inside in a manner that does not rotate with the rotating barrel as a charging negative electrode 22. A motor is arranged on the upper part of the container 10, and an endless belt is hung on the motor and the rotating shaft of the rotating barrel in order to rotate the rotating barrel by the rotation of the motor.

[0149] A nickel metal mesh having an opening in the center for passing a belt therethrough was used as the upper charging positive electrode 21. The fuel cell 500 had the same configuration as that of the third embodiment.

[0150] 25 g of a 3M potassium hydroxide aqueous solution containing 1 g of zinc oxide (particle size 0.3 μm) after discharge was added as an electrolyte from the upper portion of the regeneration device 100 , and the electrolyte was filled from the charge positive electrode 21 to the charge negative electrode 22 .

[0151] While the rotating drum was rotating at 10 rpm, a current of 100 mA was passed between the positive electrode 21 for charging and the negative electrode 22 for charging, and zinc oxide was reduced to precipitate zinc equivalent to 1 g (equivalent to 820 mAh). The zinc precipitated on the surface of the negative electrode 22 for charging and the surface of the copper ball was broken and accumulated at the bottom of the rotating drum. On the surface of the copper ball of the medium 32, as shown in FIG. Fig.14 As schematically shown in FIG. , the deposited zinc is compressed and remains in the form of a film.

[0152] The medium 32 of the crushed zinc and the copper ball with zinc remaining on the surface in the form of a film was taken out from the regeneration device 100 and placed on the negative electrode 52 for discharge of the fuel cell 500. 25 g of 3M potassium hydroxide aqueous solution was added to fill the positive electrode 51 for discharge to the negative electrode 52 for discharge, and a current of 20 mA was passed between the positive electrode 51 for discharge and the negative electrode 52 for discharge to perform discharge. As a result, the same discharge voltage and capacity as those in Example 1 were obtained.

[0153] (Comparative Example 1)

[0154] As a comparative example, Fig.10 A fuel cell 410 as a four-electrode metal-air battery is shown in . The fuel cell 410 has the same structure as the fuel cell 400 evaluated in Example 1 except that the crushing unit 30 is not included.

[0155] In the fuel cell 410 , 50 g of a 3M potassium hydroxide aqueous solution containing 2 g of zinc oxide (particle size 0.3 μm) after discharge is introduced from the top as an electrolyte and is filled from the charge positive electrode 21 and the charge negative electrode 22 to the discharge positive electrode 51 at the lower stage through the discharge negative electrode 52 .

[0156] A current of 100 mA was passed between the upper charging positive electrode 21 and the charging negative electrode 22 to reduce zinc oxide, thereby precipitating zinc in an amount of 1 g (corresponding to 820 mAh).

[0157] The deposited zinc grew toward the discharge positive electrode 21 while adhering to the charge negative electrode 22 , and did not slide down, so that the battery output power between the discharge negative electrode 52 and the discharge positive electrode 51 could not be obtained.

[0158] Table 1 shows the charge capacity and discharge capacity obtained in Examples 1 to 4 and Comparative Example 1.

[0159] [Table 1]

[0160] Charging capacity (mAh) Discharge capacity(mAh) Example 1 820 761 Example 2 820 750 Example 3 820 781 Example 4 820 791 Comparative Example 1 820 0

[0161] Explanation of symbols

[0162] 100: regeneration device, 200: discharge section, 300: fuel cell (metal-air battery of three-electrode system), 400: fuel cell (metal-air battery of four-electrode system), 410: fuel cell (metal-air battery of four-electrode system), 500: fuel cell, 1: used fuel, 2: regenerated fuel, 3: plate-shaped regenerated fuel, 10: container, 101: first storage section, 102: second storage section, 11: first container, 12: second container, 13: third container, 14: connecting section, 15: partition, 16: introduction section, 20: electrode, 21: positive electrode for charging, 22: negative electrode for charging, 30: crushing section, 32: medium, 40: recovery container, 51: positive electrode for discharge, 52: negative electrode for discharge.

Claims

1. A regeneration device for regenerating used fuel of a fuel cell using metal as fuel, and comprising a container configured to accommodate the used fuel; The used fuel contains a metal compound as a metal oxide, a metal hydroxide, or a combination thereof; The container comprises: an electrode configured to apply an electric current to the used fuel to reduce the metal compound into a metal; and The crushing unit is configured to mechanically crush at least a portion of the reduced metal generated on the surface of the negative electrode in the electrode.

2. The regeneration device according to claim 1, wherein: The container comprises a first container and a second container connected to the first container; The second container includes the electrode and the crushing unit.

3. The regeneration device according to claim 2, wherein: The second container is located below the first container. 4 . The regeneration device according to claim 1 , further comprising a third container configured to accommodate the fuel regenerated by the reduction process and the crushing process.

5. The regeneration device according to claim 4, wherein: The third container is located below the first container.

6. A fuel cell comprising the regeneration device according to claim 1 and a discharge unit, and using the metal as a fuel.

7. The fuel cell according to claim 6, comprising a positive electrode for charging, a negative electrode for both charging and discharging, and a positive electrode for discharging; The positive electrode for charging and the negative electrode for both charging and discharging constitute the electrodes; The discharge positive electrode and the charge / discharge negative electrode constitute the discharge section.

8. The fuel cell according to claim 6, comprising a positive electrode for charging, a negative electrode for charging, a positive electrode for discharging, and a negative electrode for discharging; The positive electrode for charging and the negative electrode for charging constitute the electrodes; The discharge positive electrode and the discharge negative electrode constitute the discharge section.

9. The regeneration device according to any one of claims 1 to 5, wherein: The fuel cell is a metal-air battery, a metal flow battery, or a metal slurry fuel cell.

10. The fuel cell according to any one of claims 6 to 8, wherein The fuel cell is a metal-air battery, a metal flow battery, or a metal slurry fuel cell.

11. A regeneration method for regenerating used fuel of a metal-fueled fuel cell; The used fuel contains a metal compound as a metal oxide, a metal hydroxide, or a combination thereof; The regeneration method comprises: accommodating the used fuel into a container; performing a reduction treatment of applying an electric current to the used fuel using an electrode to reduce the metal compound to a metal; At least a portion of the reduced metal generated on the surface of the negative electrode in the electrode is subjected to a mechanical crushing process to regenerate the used fuel.

12. The regeneration method according to claim 11, wherein: The fuel cell using metal as fuel has a box-type anode unit; Accommodating the used fuel in the container includes: taking out the used fuel from the cartridge anode unit and accommodating the used fuel in the container.

13. The regeneration method according to claim 11 or 12, comprising: taking out the regenerated fuel from the container; and The taken-out regenerated fuel is used as fuel for the fuel cell.

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