JP5515028B2 - Reversible fuel cell and reversible fuel cell module - Google Patents

Description

  The present invention relates to a reversible fuel cell that can store electric energy supplied at the time of charging as chemical energy, re-convert the stored chemical energy into electric energy, and a reversible fuel cell system using the same. The present invention relates to a reversible fuel cell module and a reversible fuel cell bank.

  Secondary batteries and fuel cells are highly efficient and clean energy sources. In recent years, electric vehicles, fuel cell vehicles, and trains using such secondary batteries and fuel cells as power sources have been developed worldwide.

  The fuel cell is attracting attention as a power source having high energy conversion efficiency and low environmental load. Conventionally developed and commercialized fuel cells include, for example, solid polymer fuel cells, alkaline electrolyte fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, and solid oxide fuel cells. .

  The fuel cell cannot store electricity. However, it is possible to construct a kind of power storage system by combining a fuel cell and a hydrogen production apparatus by electrolysis of water. Such a power storage system is called a reversible fuel cell (see Patent Document 1 and Patent Document 2). In such a reversible fuel cell in which a fuel cell and a water electrolyzer are combined, electrolysis of water, which is a reverse reaction of power generation, is performed using natural energy or night power when power is not generated. Thereby, this power generation system manufactures its own fuel.

  On the other hand, the secondary battery is used as a power source for electric and electronic devices that require large current discharge such as electric tools. In particular, recently, nickel hydride secondary batteries and lithium ion secondary batteries have attracted attention as batteries for hybrid vehicles driven by engines and batteries.

  A normal secondary battery is charged by receiving supply of electric energy and can store electricity. However, the secondary battery cannot be charged without a power source. For this reason, the secondary battery does not have sufficient convenience. Therefore, Patent Document 3 discloses a secondary battery that can be charged using gas. Patent Document 4 discloses a new type of fuel cell in which a fuel cell and a secondary battery are combined using manganese hydroxide as a positive electrode active material and a hydrogen storage alloy as a negative electrode active material. .

  Patent Documents 5 and 6 propose a battery cooling method. That is, a cooling method including efficiently dissipating heat by a protrusion provided on the surface of the battery case has been proposed. Furthermore, a cooling method has been proposed which includes providing a metal plate with a hole between the assembled batteries and flowing cooling air through the hole.

JP 2002-348694 A JP 2005-65398 A JP 2010-15729 A JP 2010-15783 A JP 2009-016285 A JP 2003-007355 A

  The secondary battery can store electricity. However, the amount of the negative electrode and the positive electrode active material depends on the volume of the battery. For this reason, there is a limit to the electric capacity that can be stored in the battery. In the nickel metal hydride secondary battery, the ratio (weight ratio) of the weight of the reducing substance and the oxidizing substance that can be stored with respect to the weight of the active material is small. For example, the weight ratio of hydrogen that can be stored in an AB5 type hydrogen storage alloy including a misch metal nickel alloy is about 1.2% by weight. For this reason, it is difficult for the secondary battery to significantly increase the energy density.

On the other hand, the fuel cell generates power (discharges) using hydrogen gas or oxygen gas supplied from the outside. For this reason, the fuel cell does not have a problem related to the limit of energy density as occurs in the secondary battery. In general, in order to use a fuel cell, a device or member for supplying hydrogen gas and oxygen gas to an electrode portion is required . Further, the followability of the fuel cell with respect to the load fluctuation is inferior to that of the secondary battery. For this reason, it is difficult to use only a fuel cell as a power source of a device having a large load fluctuation such as a vehicle. Normally, a fuel cell is used with a power storage device such as a secondary battery or a capacitor. The reaction field of the fuel cell is an extremely small interface where three phases of solid (electrode), liquid (electrolyte), and gas (hydrogen gas, oxygen gas) are in contact. For this reason, the output characteristics of the fuel cell are inferior to those of the secondary battery. In order to improve output characteristics, there is also a technique using platinum as a catalyst. However, this approach is costly.

  Furthermore, the gas taken out from the hydrogen production apparatus (for example, Patent Document 1) is oxyhydrogen gas in which the ratio of hydrogen to oxygen is 2: 1. Therefore, care must be taken to ensure safety.

  The secondary battery disclosed in Patent Document 3 can be discharged like a fuel cell by receiving gas supply. For this reason, the electric capacity of the secondary battery is not limited by the amount of the active material unlike a normal secondary battery. However, an apparatus or member for supplying hydrogen gas and oxygen gas to the electrode portion is required.

  The “fuel cell storage battery” disclosed in Patent Document 4 generates power (discharges) by receiving a gas supply from a gas storage chamber provided independently. For this reason, an additional apparatus or member for supplying hydrogen gas and oxygen gas to an electrode part is unnecessary. Moreover, since the gas storage chamber is provided independently, safety is ensured. However, since the battery described in Patent Literature 4 uses manganese hydroxide as the positive electrode active material, trimanganese tetraoxide that does not contribute to the charge / discharge reaction is generated while charging / discharging is repeated. Therefore, this fuel cell has a problem that the life characteristics are poor.

A zinc-manganese primary battery is widely known as an aqueous battery based on manganese dioxide as a positive electrode. Zinc-manganese batteries are exclusively used as primary batteries and are not used as secondary batteries. The reason is described below. In other words, the positive electrode of the manganese battery changes in the discharge process from manganese dioxide MnO ₂ → manganese oxyhydroxide MnOOH → manganese hydroxide Mn (OH) ₂ . At this time, if discharge is performed until manganese hydroxide is generated, trimanganese tetraoxide Mn ₃ O ₄ that cannot be charged is generated. That is, while the discharge process (manganese oxyhydroxide → manganese hydroxide) and the charge process (manganese hydroxide → manganese oxyhydroxide) are repeated, the irreversible substance produced in the positive electrode, manganese trioxide, is produced. There is a problem of increasing.

  Manganese tetroxide has a characteristic of low conductivity. If the conductivity is low, it takes time to charge, so that it is difficult to fully charge. Moreover, when electroconductivity is low, charging efficiency will also worsen. Therefore, when the trimanganese tetroxide increases, the performance of the fuel cell deteriorates and finally it cannot be used. For this reason, manganese dioxide is exclusively used for primary batteries and is not currently used as a positive electrode active material for secondary batteries.

  The separator which is one of the constituent elements of the battery prevents a short circuit between the positive electrode and the negative electrode. The separator is an important part for the battery. The separator is made of a material having a small thermal conductivity (a material that is difficult to transmit heat). In the wound battery, the stacked electrodes and separator are wound in a spiral shape. For this reason, the wound battery has many separators interposed from the battery center to the surface. Therefore, although the surface temperature of the wound battery is close to the ambient temperature, the temperature of the central portion is high. For this reason, even if the outside of the wound battery is cooled, the inside of the battery is not cooled to a necessary level and remains at a high temperature.

  Various methods relating to battery cooling have been proposed in US Pat. These are all effective for cooling the surface of the battery case. However, the wound battery has many separators with low thermal conductivity. For this reason, these methods are not effective as a method for cooling the wound battery.

  The present invention has been made in view of the current state of the prior art. In the present invention, a reaction mechanism of a secondary battery having excellent load followability is incorporated into a fuel cell having a high energy density. This provides a reversible fuel cell that is excellent in power density, energy density, and load followability, secures safety, and has excellent life characteristics.

  The inventors have intensively studied to solve the above problems, and completed the reversible fuel cell of the present invention.

  The reversible fuel cell of the present invention (hereinafter referred to as the present fuel cell) has a positive electrode containing manganese dioxide, a negative electrode containing a hydrogen storage material, a separator interposed between the positive electrode and the negative electrode, and an electrolyte. The negative electrode and the positive electrode are power generation electrodes, and are electrodes that electrolyze the electrolytic solution using a current supplied from the outside.

  According to this configuration, the positive electrode and the negative electrode each have the active material. For this reason, this fuel cell has a function as a storage battery. That is, it is possible to generate electric power without receiving supply of gas, and it is also possible to charge using electric current. Furthermore, when the fuel cell is further supplied with current to the fully charged fuel cell, the electrolyte is hydrolyzed. Thereby, oxygen gas and hydrogen gas are generated from each electrode. The positive electrode and the negative electrode function as electrodes for generating electricity using oxygen and hydrogen as fuel, respectively. That is, the positive electrode and the negative electrode of the present fuel cell not only function as electrodes of the present fuel cell, but also function as electrodes for water splitting.

In the present fuel cell, the discharge reaction of the negative electrode and the positive electrode may be reactions represented by Formula (1) and Formula (3), respectively, and the charge reaction of the negative electrode and the positive electrode may be represented by Formula (2), respectively. ) And the formula (4).
^{MH → M + H + + e} - (1)
M + 1 / 2H ₂ → MH (2)
MnO ₂ + H ⁺ + e ⁻ → MnOOH (3)
MnOOH + O ₂ → MnO ₂ + H ₂ O (4)
However, in Formula (1) and (2), M shows a hydrogen storage material.

As shown in the equations (2) and (4) showing the charging process of the fuel cell, the negative electrode and the positive electrode are chemically charged with hydrogen and oxygen, respectively.
As shown in the above reaction formulas (3) and (4), the positive electrode active material is repeatedly charged and discharged between manganese dioxide and manganese oxyhydroxide.

  When discharging until manganese dioxide becomes manganese hydroxide, trimanganese tetraoxide is produced. Therefore, the inventors thought that if manganese dioxide is not discharged until it becomes manganese hydroxide, trimanganese tetroxide does not occur and the positive electrode does not deteriorate. The inventors have confirmed this through experiments. This experiment is shown below.

  The inventors investigated the transition of the charge / discharge cycle characteristics of manganese dioxide according to the discharge reaction depth through experiments. The results are shown in FIGS. 19A and B. 19A and 19B, the vertical axis represents the electrode potential, and the horizontal axis represents the amount of discharge electricity. The discharge curve shown in FIG. 19A is obtained when charging and discharging in a one-electron reaction is repeated 30 times. The discharge curve shown in FIG. 19B is obtained when charging and discharging in a two-electron reaction is repeated 30 times. According to FIG. 19A, even if charging / discharging is repeated, the discharge curve hardly changes. On the other hand, according to FIG. 19B, it turns out that the amount of discharge electricity is reducing as charging / discharging is repeated. The one-electron reaction is a discharge reaction in which manganese dioxide is changed to manganese oxyhydroxide. The two-electron reaction is a discharge reaction in which manganese dioxide becomes manganese hydroxide through manganese oxyhydroxide. From the experimental results shown in FIGS. 19A and 19B, it can be seen that the discharge characteristics are almost uniform as long as the one-electron reaction remains. Furthermore, it can be seen that when a two-electron reaction occurs, the discharge characteristics gradually deteriorate as charging and discharging are repeated. Thereby, it turns out that an electrode deteriorates.

  Inventors performed XRD measurement with respect to the electrode after charging / discharging in order to investigate the cause of this deterioration. The result is shown in FIG. As shown in the graph (a) of FIG. 20, when charging and discharging are repeated by a one-electron reaction, new peaks are hardly generated except for the one corresponding to the crystal structure of the electrode before the experiment (for comparison, FIG. The measurement result of the electrode before the experiment is shown in graph (s) of 20). However, as shown in the graph (b) of FIG. 20, when charging and discharging are repeated by a two-electron reaction, the characteristic peak derived from manganese dioxide is almost eliminated, while the peak derived from manganese trioxide appears. From this, it can be seen that the generation of trimanganese tetraoxide can be suppressed by stopping the discharge at the stage where the manganese dioxide becomes manganese oxyhydroxide.

  Even if manganese dioxide is oxidized by electric discharge, if the electrode is brought into contact with oxygen, it returns to manganese dioxide, so that the reaction does not proceed to manganese hydroxide, and irreversible manganese trioxide does not occur. That is, manganese dioxide was successfully used as a positive electrode by charging it in contact with oxygen at the stage of oxidation of manganese dioxide.

21A and 21B are diagrams showing experimental results showing that the positive electrode can be charged by contacting with oxygen gas.
FIG. 21 shows a case where manganese oxyhydroxide is used as a positive electrode, silver (Ag) is used as a reference electrode, a half cell is formed using an alkaline electrolyte, and charging and discharging are performed by pressurizing oxygen gas. The potential change of the positive electrode is plotted against time. The vertical axis in FIG. 21 represents the potential of the positive electrode (V vs. Ag / AgCl), and the horizontal axis represents the elapsed time (minutes). In a half cell having manganese dioxide as the positive electrode and silver as the reference electrode, the cutoff potential when the positive electrode becomes manganese oxyhydroxide by discharge is -0.5V. Before charging (time zero) in FIG. 21, the positive electrode potential is −0.5 V, which indicates that the positive electrode is manganese oxyhydroxide.

  FIG. 21A (i) is a graph showing the potential with respect to the reference electrode after oxygen gas is pressurized and applied to the positive electrode. (Ii) of FIG. 21A is a graph when the supply of oxygen gas is stopped and discharging is performed at 0.2C. As shown in FIG. 21A, when the positive electrode is brought into contact with oxygen gas (solid line), after 60 minutes, the positive electrode is almost fully charged and then discharged at 0.2C. Show. On the other hand, when the oxygen gas is not brought into contact (dotted line), the positive electrode is hardly charged. As a result, it was confirmed that the fuel cell cathode reaction (oxidation-reduction reaction) was caused by the oxygen gas, and that the discharge by the secondary battery reaction occurred after the oxygen gas was shut off. FIG. 21B shows the state of charging with oxygen gas during the discharge state at 0.2C. From this figure, it can be seen that charging with oxygen gas is possible even during discharge. From the experimental results shown in FIGS. 21A and 21B, it was confirmed that charging was possible by supplying oxygen gas to the positive electrode.

In the reaction formula of the present fuel cell, H _{2 in} formula (2) may be hydrogen gas. Further, O ₂ in the formula (4) may be oxygen dissolved in the electrolytic solution. The fuel cell may have a first oxygen storage chamber for holding an electrolyte in which oxygen is dissolved and a hydrogen storage chamber for holding hydrogen gas inside the battery.

  According to this configuration, when the active material in the fully charged electrode is further charged by current, hydrogen gas is generated in the negative electrode by water electrolysis (hereinafter simply referred to as electrolysis). This hydrogen gas can be stored in a hydrogen storage chamber. In addition, oxygen gas generated at the positive electrode by electrolysis is dissolved in the high-pressure electrolyte. For this reason, oxygen can be stored in the first oxygen storage chamber as an oxygen-dissolved electrolyte. That is, hydrogen gas and oxygen gas generated at the negative electrode and the positive electrode by electrolysis can be stored separately in each storage chamber without contacting and reacting with each other.

  The hydrogen gas stored in the hydrogen storage chamber and the oxygen stored in the first oxygen storage chamber can be reconverted to electrical energy and used when the battery is discharged. In particular, oxygen gas generated at the positive electrode is dissolved in the electrolyte and is not stored in a gas state. For this reason, the safety of handling oxygen is improved. When the battery is discharged, electric energy can be taken out as a secondary battery. For this reason, rapid discharge becomes possible and load followability can be improved.

  As described above, the electric capacity of the secondary battery is determined by the amount of the active material contained in the electrode material. For this reason, it is difficult to increase the energy density of the secondary battery. However, in this fuel cell, electrical energy that can be taken out is stored as chemical energy in each storage chamber.

  As a result, it is possible to increase the amount of chemical energy stored per volume and improve the volume energy density of the fuel cell by increasing the pressure resistance and sealing performance of each storage chamber and the battery including the storage chamber. It becomes.

  According to this configuration, the manganese dioxide of the positive electrode temporarily becomes manganese oxyhydroxide by discharge. However, it is charged with oxygen dissolved in the electrolyte and returns to manganese dioxide. Therefore, the positive electrode does not discharge so much that manganese dioxide changes from manganese oxyhydroxide to another substance. Due to charging / discharging, the active material of the positive electrode changes between manganese dioxide and manganese oxyhydroxide. For this reason, trimanganese tetraoxide which does not contribute to charge / discharge does not occur. Moreover, since trimanganese tetroxide does not occur, a decrease in conductivity is also suppressed.

  The first oxygen storage chamber and the hydrogen storage chamber of this configuration are not necessarily dedicated independent spaces. These storage chambers may be formed in a gap of a composite material including positive and negative electrode active materials or the like, or a gap generated inside the battery.

  In the fuel cell, the first oxygen storage chamber and the hydrogen storage chamber may be separated by a movable member.

According to this configuration, the first oxygen storage chamber and the hydrogen storage chamber may be provided adjacent to each other. Since the two chambers are partitioned by a movable member, if the pressure of the hydrogen storage chamber becomes high due to hydrogen gas generated by overcharging, the movable member is deformed under the influence of the pressure. By this deformation, the electrolyte solution in the first oxygen storage chamber is compressed, and the pressure of the electrolyte solution is equalized with the pressure in the hydrogen storage chamber to become a high pressure. The bulk modulus of liquid is very large compared to that of gas. For this reason, the deformation amount of the movable member is very small. The movable member may be a flexible member or may include an elastic body. The movable member may have a thin plate-like or film-like structure. Furthermore, the movable member may be a positive electrode or a negative electrode. The movable member may be a synthetic resin such as rubber or polypropylene, or a thin metal film.
A communication passage may be provided between the first oxygen storage chamber and the hydrogen storage chamber. In this case, the pressure in the hydrogen storage chamber may be transmitted to the electrolytic solution in the first oxygen storage chamber via a movable member disposed in the communication passage. In this case, the movable member may be a piston.

  In the fuel cell, the movable member may be a flexible member, and the flexible member preferably includes the positive electrode, the negative electrode, and a separator.

  In the present fuel cell, the cylindrical positive electrode and the cylindrical negative electrode are arranged via the separator inside a cylindrical case via a radial space, and the positive electrode is opposite to the separator. The first oxygen storage chamber is formed to contact the surface of the negative electrode, the hydrogen storage chamber is formed to contact the surface of the negative electrode opposite to the separator, and the first oxygen storage chamber is The hydrogen storage chamber is disposed inside the negative electrode, or the hydrogen storage chamber is disposed in the radial space, and the first oxygen storage chamber is You may arrange | position inside the said positive electrode. In this configuration, the case functions as an exterior body.

  The fuel cell is electrically connected to a negative electrode terminal provided at one end of the case in the axial direction and electrically connected to the negative electrode, and to the positive electrode provided at the other end in the axial direction of the exterior body. A positive electrode terminal connected; a protrusion provided on one of the positive electrode terminal and the negative electrode terminal; and a hole provided on either the positive electrode terminal or the negative electrode terminal. The protrusion and the hole may be fitted so that two reversible fuel cells are connected in series. In this configuration, the case functions as an exterior body.

  The fuel cell module of the present invention has a plurality of battery units connected in series, and the battery units face each other so as to sandwich the plurality of reversible fuel cells and the plurality of reversible fuel cells. A plurality of the current collector plates, wherein the positive electrode terminal is connected to the one current collector plate, and the negative electrode terminal is connected to the other current collector plate. These reversible fuel cells may be connected in parallel to each other via the current collector plate.

  The fuel cell includes an outer shell having a cylindrical body portion, and a bulging portion that is disposed at both end openings of the body portion and bulges outward from the opening portion and covers the opening portion, and the outer shell. The first oxygen storage chamber provided in the inner space of the bulging portion inside the container and the axially stored inside the outer shell, both ends of which are open to the first oxygen storage chamber A tubular current collector, the positive electrode is disposed on an outer periphery of the current collector, the separator covers the periphery of the positive electrode, and the hydrogen storage chamber includes the separator and the Formed between the outer shell, the negative electrode is filled in the hydrogen storage chamber, the electrolyte is stored in the first oxygen storage chamber, and the first oxygen storage chamber passes through the current collector. It is preferable to be able to travel between oxygen storage rooms.

  The fuel cell further includes an exterior body having a cylindrical body, and a rod-shaped current collector that penetrates the positive electrode, the negative electrode, and the separator, and the positive electrode, the negative electrode, and the separator are disposed on the body. It is laminated in the axial direction and housed in the exterior body, the positive electrode has a notch formed by cutting out a part of the outer periphery, and the outer periphery of the positive electrode is The positive electrode is not in contact with the current collector, and the negative electrode has a U-shaped cross section that opens in the inner circumferential direction. The negative electrode and the current collector are in contact with each other, a space surrounded by the negative electrode and the current collector forms the hydrogen storage chamber, and the outer dimensions of the negative electrode are Smaller than the inner dimension of the part, and communicated with the notch part between the negative electrode and the body part That the electrolyte reservoir is provided, wherein the first oxygen storage chamber may include the cutout portion and the electrolyte reservoir.

In this configuration, the exterior body may include a pipe-shaped body and a lid member that covers the opening of the body. Moreover, the exterior body may contain the low and low cylindrical can and the lid member provided in the opening part.
If the exterior body is cylindrical, the positive electrode contacts the exterior body because the outer diameter of the positive electrode is larger than the inner diameter of the body. Moreover, since the size of the hole of the positive electrode through which the current collector passes is larger than the outer diameter of the current collector, the positive electrode and the current collector are not in contact with each other. Similarly, the hole size of the negative electrode is smaller than the outer diameter of the current collector, and the negative electrode and the current collector are in contact with each other.

  The reversible fuel cell system of the present invention has the present fuel cell, and an oxygen storage source and a hydrogen storage source connected to the fuel cell, and the oxygen storage source contains oxygen dissolved in oxygen gas or electrolyte, The fuel cell can be supplied and oxygen gas generated in the fuel cell can be stored in a gas state or dissolved in an electrolyte, and the hydrogen gas storage source can supply hydrogen gas to the fuel cell. The hydrogen gas generated in the fuel cell may be storable.

  The reversible fuel cell system of the present invention is connected to the fuel cell, the fuel cell, a salt concentration adjusting device for removing water contained in the electrolyte, and the fuel cell. An oxygen concentration adjusting device that adjusts the dissolved oxygen concentration by supplying oxygen.

In the present fuel cell, H ₂ in the formula (2) may be hydrogen gas, and O _{2 in the} formula (4) may be oxygen gas. Whether to store hydrogen gas generated at the negative electrode or to supply hydrogen gas to the negative electrode and to store a hydrogen storage chamber provided in contact with the negative electrode and oxygen gas generated at the positive electrode Or you may provide the 2nd oxygen storage chamber provided in contact with the said positive electrode for supplying oxygen to the said positive electrode.

  According to this configuration, when charging is performed with an electric current when the inside of the electrode is in a fully charged state, the hydrogen gas generated at the negative electrode and the oxygen gas generated at the positive electrode are brought into contact with each other and reacted by electrolysis. Without being stored in the hydrogen storage chamber and the second oxygen storage chamber. Therefore, hydrogen gas and oxygen gas can be stored in each storage chamber without requiring an additional gas supply source, supply passage, pressure increase device, and the like. The stored hydrogen gas and oxygen gas can be converted into electric energy and reused when the battery is discharged. When the battery is discharged, electric energy can be taken out by a normal discharge reaction as a secondary battery. That is, electric energy is output through the electrode reaction of the secondary battery. Therefore, rapid charge / discharge and excellent charge / discharge followability can be obtained.

The fuel cell includes a positive electrode containing manganese dioxide, a negative electrode containing a hydrogen storage material, a separator interposed between the positive electrode and the negative electrode, and an electrolyte containing an alkaline aqueous solution, and is generated at the negative electrode. A reversible fuel cell comprising a hydrogen storage chamber for storing hydrogen gas and an oxygen storage chamber for storing oxygen gas generated at the positive electrode, wherein the negative electrode is disposed on a surface in contact with the hydrogen storage chamber. and a material having a gender, and / or, wherein the positive electrode comprises a material having a hydrophobic that disposed in the surface in contact with the oxygen storage chamber, a material having a hydrophobic, carbon or Teflon (registered trademark ) .

  According to this structure, the surface which contacts the separator of a negative electrode has hydrophilic property. This surface is almost always wet with the electrolyte. As a result, this surface prevents the gas from passing through the negative electrode. Moreover, the ionic conductivity of the negative electrode is ensured. The surface of the negative electrode that is in contact with the hydrogen gas has hydrophobicity. Thereby, since a negative electrode does not get wet, the favorable contact with a negative electrode and hydrogen gas is maintained. The surface of the positive electrode that contacts the separator has hydrophilicity. This surface is almost always wet with the electrolyte. This surface thereby prevents gas from passing through the positive electrode. Moreover, the ionic conductivity of the positive electrode is ensured. Further, the surface of the positive electrode that is in contact with oxygen gas has hydrophobicity. Thereby, since the positive electrode is not wetted, good contact between the positive electrode and oxygen gas is maintained. The separator almost always contains an electrolytic solution, thereby preventing the passage of gas. Thereby, a hydrogen store room and a 2nd oxygen store room become independent. Therefore, hydrogen gas and oxygen gas are stored independently without intermingling with each other.

In the secondary battery, a solid and a liquid react. For this reason, since the secondary battery has a large reaction area, the output can be increased. However, an electrode that is solid holds an oxidizing agent and a reducing agent. For this reason, the amount of energy of the secondary battery is small. On the other hand, the reaction surface of the fuel cell is an extremely small interface where three phases of solid (electrode), liquid (electrolyte), and gas (hydrogen gas, oxygen gas) are in contact. Therefore, it is difficult to increase the output of the fuel cell. However, since the fuel cell supplies the oxidizing agent and the reducing agent as they are, the energy density thereof is increased. A battery that combines the advantages of both is the fuel cell.
By the way, the characteristics of a secondary battery having a reaction surface between a solid (electrode) and a liquid (electrolyte) and the characteristics of a fuel cell having a reaction surface between a solid (electrode), a gas and a liquid can be measured in one electrode. If it can be realized, it is possible to further increase the output and increase the energy capacity. Therefore, the interface of the electrode that contacts the electrolyte may be made hydrophilic, while the interface of the electrode that contacts the gas may be made hydrophobic. Further, one surface of the electrode may be made hydrophilic while the other surface of the electrode may be made hydrophobic. Further, the entire electrode may be made of a material having both hydrophilicity and hydrophobicity.

  In the fuel cell, the electrolyte solution may be held in the second oxygen storage chamber. In this configuration, the electrolytic solution may be held in the second oxygen storage chamber, and oxygen gas may be held in the upper space. For this reason, the water produced on the surface of the positive electrode when discharged is supplied to the electrolyte. Electrolysis during charging is performed at the positive electrode interface. For this reason, it is convenient that the electrolytic solution is held in the second oxygen storage chamber.

  When the present fuel cell has a cylindrical outer casing, the cylindrical positive electrode and the cylindrical negative electrode are disposed via the separator inside the outer casing via a radial space, and the positive electrode The second oxygen storage chamber is formed so as to be in contact with the surface on the opposite side of the separator, and the hydrogen storage chamber is formed so as to be in contact with the surface of the negative electrode on the side opposite to the separator. Two oxygen storage chambers are disposed in the radial space and the hydrogen storage chamber is disposed inward of the negative electrode, or the hydrogen storage chamber is disposed in the radial space, and The second oxygen storage chamber may be disposed inside the positive electrode.

In this configuration, an additional member for forming the hydrogen storage chamber and the second oxygen storage chamber is unnecessary. For this reason, the fuel cell has a simple structure including only the minimum necessary members. Therefore, it is possible to reduce the size of the fuel cell and to secure pressure resistance. In addition, the energy density of the fuel cell can be increased, and the assembly operation of the fuel cell is facilitated.
The fuel cell includes the cylindrical positive electrode disposed inside the outer package via a radial space and the cylindrical negative electrode disposed inside the positive electrode via the separator. The second oxygen storage chamber may be formed in the radial space, and the hydrogen storage chamber may be formed inside the negative electrode. By adopting a structure in which the positive electrode is arranged outside the negative electrode in this way, the surface area of the positive electrode can be made larger than the surface area of the negative electrode. Since the output of the battery is proportional to the electrode surface area, the output can be increased accordingly.

  The present fuel cell is electrically connected to the negative electrode terminal provided at one end in the axial direction of the outer casing and electrically connected to the negative electrode, and to the positive electrode provided at the other end in the axial direction of the outer casing. A positive electrode terminal connected to, a protrusion provided on either the positive electrode terminal or the negative electrode terminal, and a hole provided on either the positive electrode terminal or the negative electrode terminal, The protrusion and the hole may be fitable so that the two fuel cells are connected in series.

  According to this configuration, the protrusions and the holes of the two fuel cells can be connected. Thereby, a plurality of the fuel cells can be connected in series without requiring wiring. While providing a convex part in the outer periphery of a projection part, you may provide a groove (groove) in the inner peripheral surface of a hole. In this case, the convex part of the projection part may be fitted into the groove of the hole part. As a result, the two fuel cells can be reliably connected.

  The fuel cell module according to the present invention may have a plurality of battery units connected in series. This battery unit has a plurality of fuel cells and a pair of current collector plates provided so as to sandwich the plurality of fuel cells, and the positive terminal is connected to the one current collector plate The fuel cell may be connected in parallel to each other via the current collector plate by connecting the negative electrode terminal to the other current collector plate.

  According to this configuration, the fuel cell is disposed between the conductive current collecting plates. Thereby, the wiring which connects between this fuel cell can be abbreviate | omitted. Therefore, modularization of the battery becomes easy. The current collector plate may have a nickel-plated aluminum plate. A through hole may be provided in the current collector plate. And you may let the projection part of this fuel cell pass through a through-hole, and may be fitted in the hole part of another this fuel cell. Thus, the current collector plate serves as a bracket that connects the batteries in series and in parallel, and allows the batteries to be fixed. Thereby, assembly of a battery module becomes easy.

  The fuel cell further includes an oxygen gas circulation port communicating with the second oxygen storage chamber, and a hydrogen gas circulation port communicating with the hydrogen storage chamber, wherein the hydrogen gas and the second oxygen storage in the hydrogen storage chamber It may be possible for the oxygen gas in the chamber to be taken out of the fuel cell separately.

  In this configuration, the oxygen gas circulation port may be provided in the exterior body, and the hydrogen gas circulation port may be provided in the exterior body or the positive electrode terminal. In this way, the gas accumulated in the hydrogen storage chamber and the second oxygen storage chamber can be taken out of the fuel cell and stored in another container. Furthermore, it becomes possible to send hydrogen gas and oxygen gas from the container provided outside to the hydrogen storage chamber and the second oxygen storage chamber.

  A battery bank according to the present invention includes a plurality of fuel cells connected to each other, a first hydrogen gas pipe including an electric conductor having a connection portion that can be airtightly connected to the hydrogen gas circulation port, and the oxygen A first oxygen gas pipe including an electric conductor having a connection portion that can be airtightly connected to the gas distribution port, and the first hydrogen gas pipe is connected to the second hydrogen gas pipe via an insulator. The first oxygen gas pipe is connected to the second oxygen gas pipe via an insulator, and the adjacent first oxygen gas pipe and the first hydrogen gas pipe are electrically connected by a conductor. The second hydrogen gas pipe may be connected to the hydrogen gas tank, and the second oxygen gas pipe may be connected to the oxygen gas tank. According to this configuration, the gas pipe serves as a current path. For this reason, wiring can be omitted.

2. The reversible fuel cell according to claim 1, wherein the fuel cell is a reversible fuel cell according to claim 1, wherein the negative electrode case is in contact with the negative electrode and is opposed to the positive electrode through a separator, and the negative electrode is in contact with the positive electrode. A positive electrode case disposed opposite to the separator, a hydrogen storage chamber is formed in a space between the negative electrode case and the negative electrode, and an oxygen storage chamber is formed between the positive electrode case and the positive electrode. A reversible fuel cell in which a unit cell formed in a space between the unit cell and the unit cell connected in series is connected to the positive electrode terminal of the unit cell connected in series. It is desirable that the positive electrode case of the unit cell and the negative electrode case of the adjacent unit cell are arranged so as to contact each other.

  According to this configuration, the negative electrode case and the positive electrode case function as a negative electrode terminal and a positive electrode terminal, respectively. Moreover, the wiring for connecting the unit cells is not necessary. Moreover, it is not necessary to prepare a pressure vessel for each cell. A single pressure-resistant structure may be prepared for the fuel cell.

  The fuel cell bank according to the present invention includes a metal wire, a structure, a circuit breaker capable of opening and closing, and a bus bar, and one end of the metal wire is attached to the reversible fuel cell module. The other end of the wire is attached to the structure, whereby a plurality of the reversible fuel cell modules can be suspended from the structure, and the positive electrodes of the adjacent reversible fuel cell modules A terminal and a negative electrode terminal may be connected by the bus bar via the circuit breaker.

  According to this configuration, the reversible fuel cell module can be suspended from a structure such as a steel tower by a plurality of metal wires. The metallic wire may be inserted with a pressure-resistant material such as an insulator or may be an insulating belt. A plurality of such reversible fuel cell modules may be arranged, and the positive electrode and the negative electrode may be connected by a conductive bus bar. Circuit breakers may be arranged between the bus bars and at the output of the battery system.

  According to this hanging structure, first, a large structure can be installed. A huge structure such as a bridge or a boiler has a large weight. For this reason, it becomes difficult to use a self-supporting structure that supports the weight in the lower part. Therefore, by adopting a hanging structure, it is possible to make the stress to each part of the battery uniform and to solve the trouble due to distortion. By using a suspended structure, it is possible to ensure the withstand voltage performance and the withstand voltage between modules.

  In the fuel cell, the manganese dioxide may function as a catalyst for a charging reaction at a positive electrode, and the hydrogen storage material may function as a catalyst for a charging reaction at a negative electrode.

  According to this configuration, at the time of discharging, in each of the negative electrode and the positive electrode, the amount of electricity reduced by the discharge is stored in the hydrogen gas stored in the hydrogen storage chamber and in the first or second oxygen storage chamber and oxygen. It is compensated by charging with oxygen. Specifically, in the negative electrode, protons are released from the hydrogen storage alloy (MH) in a charged state, as shown in the reaction formula (1) representing the discharge reaction. Then, as shown in the reaction formula (2), the released protons are supplemented with hydrogen gas. Thereby, the charged state of the negative electrode is maintained.

On the other hand, in the positive electrode, manganese oxyhydroxide (MnOOH) is produced by reducing charged manganese dioxide (MnO ₂ ) as shown in the reaction formula (3) representing the discharge reaction. This manganese oxyhydroxide is oxidized again by oxygen as shown in the reaction formula (4). Thereby, the charge state of a positive electrode is maintained. Thereby, hydrogen gas and oxygen in each storage room are consumed.

  That is, in this fuel cell, as long as hydrogen gas and oxygen are supplied, the electricity lost by the discharge is immediately charged by the hydrogen gas and oxygen. Therefore, the present fuel cell almost always maintains a state close to full charge. That is, since the negative electrode maintains the occlusion state almost always with hydrogen gas, expansion and contraction of the negative electrode volume due to charge / discharge can be suppressed. As a result, the negative electrode has excellent life characteristics. Furthermore, even if the amount of the active material is small, the negative electrode has the above-described action, so that the amount of heavy and expensive hydrogen storage alloy can be reduced. As a result, it is possible to reduce the weight and cost of the battery.

In the present fuel cell, the positive electrode may further contain higher-order manganese oxide in addition to manganese dioxide. Here, the higher-order manganese oxide includes Mn ₂ O ₅ , Mn ₂ O ₇ and MnO ₅ . These higher-order manganese oxides are temporarily generated in the positive electrode when the positive electrode is overcharged when the electrolytic solution is hydrolyzed.

In the fuel cell, the content of trimanganese tetraoxide (Mn ₃ O ₄ ) contained in the positive electrode is preferably 5% by weight or less based on the weight of the positive electrode. If hydrogen gas and oxygen are almost always supplied, trimanganese tetroxide is not generated. However, if hydrogen gas or oxygen is temporarily insufficient, trimanganese tetroxide can be produced. The amount exceeding 5% by weight can be a problem. Depending on the application, this amount can be allowed to be about 5% by weight or less. In addition, the positive electrode weight here does not include the weight of the current collector.

  In the fuel cell, the content of manganese dioxide contained in the positive electrode is preferably in the range of 20 to 99.8% by weight based on the weight of the positive electrode. In addition, the positive electrode weight here does not include the weight of the current collector.

In this fuel cell, it is preferable that the average particle diameter of manganese dioxide contained in the positive electrode is in the range of 1 to 100 μm. Here, the average particle size is JIS
This is a value expressed by using a sphere equivalent diameter by the light scattering method of Z8910.

  In the present fuel cell, manganese dioxide contained in the positive electrode may be carbon-coated.

  Cobalt may be used as the conductive treatment. However, cobalt is expensive. Usually, carbon is used as a material having conductivity. However, carbon is oxidized to carbon dioxide gas. For this reason, it becomes difficult to ensure the conductivity. The inside of the fuel cell is under a hydrogen atmosphere. For this reason, carbon can maintain conductivity without being oxidized.

  In the fuel cell, the hydrogen storage material is preferably a hydrogen storage alloy or at least one metal selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, and Ni.

In the present fuel cell, the separator is preferably a microporous membrane having an average pore diameter of 0.1 to 10 μm.
In the fuel cell, the negative electrode may include a hydrophilic material disposed on a surface in contact with the separator and a hydrophobic material disposed on a surface in contact with the hydrogen storage chamber. Good.

  In the present fuel cell, the electrolyte solution preferably contains a thickener. The thickening agent may be at least one polyacrylate selected from the group consisting of lithium polyacrylate, sodium polyacrylate, and potassium polyacrylate.

  The fuel cell preferably has an open circuit terminal voltage in the range of 0.8 to 1.48V. That is, the terminal voltage when one fuel cell is opened may be in the range of 0.8 to 1.48V. When the positive electrode is manganese oxyhydroxide and the electrolyte pressure is 0.1 MPa, the terminal voltage is about 0.8V. On the other hand, when the positive electrode is manganese dioxide and the electrolyte is at a high voltage, the terminal voltage is 1.48V. The open circuit terminal voltage is determined by the state of charge of the positive electrode and the pressure of the electrolyte.

  The fuel cell further includes an exterior body, and a current collector passing through the positive electrode, the negative electrode, and the separator in an axial direction of the exterior body, and either the positive electrode or the negative electrode Is a first electrode that is in contact with and electrically connected to the inner surface of the exterior body, and the other of the positive electrode and the negative electrode is not in contact with the inner surface of the exterior body. A laminated type, wherein the second electrode is in contact with and electrically connected to the current collector, while the first electrode is not in contact with the current collector. It may be a battery.

  According to this configuration, the separator holds the electrolytic solution and insulates between the positive and negative electrodes. The separator allows the permeation of ions. The exterior body is a metal, and the material thereof may contain iron, aluminum, or titanium. The exterior body functions as a terminal of the electrode (first electrode) that is in contact with the exterior body. The exterior body may be a hollow can. The positive and negative electrodes and the separator may be formed in a sheet shape. Each electrode may be stacked in the axial direction of the exterior body and housed inside the exterior body. The outer diameter of the first electrode (the dimension in the direction perpendicular to the thickness direction) may be made slightly larger than the inner diameter of the exterior body. The whole or part of the outer periphery of the first electrode is in contact with the inner surface of the exterior body. The first electrode is pressed into the exterior body, and the first electrode is connected to the exterior body with a small thermal resistance. For this reason, an exterior body cools an electrode effectively.

  On the other hand, the outer diameter of the second electrode may be made smaller than the inner diameter of the exterior body. The second electrode is not in contact with the exterior body and is insulated. The exterior body may be a can and may contain iron, aluminum, or titanium.

  The heat generated in the first electrode is directly transferred to the exterior body. Since there is no defective heat conductor in the middle, the thermal gradient (temperature difference) is small. Heat generated in the second electrode is transmitted to the first electrode through the separator. There is only one separator with a small thermal conductivity interposed in the middle, and it does not have a large thermal resistance. For this reason, the thermal gradient is kept small. Furthermore, the electrode group including the positive and negative electrodes and the separator is pushed into the exterior body with a large pressure in the axial direction. As a result, the second electrode is strongly pressed against the first electrode. For this reason, the heat transfer of the second electrode is further increased. The reason why the temperature gradient of the wound battery is large is that there are multiple separators that are difficult to transfer heat between the outer package and the electrode, and because of its structure, it is difficult to wind with a large force. Therefore, the heat transfer between the electrodes cannot be increased.

  As described above, the present fuel cell has a small temperature gradient and can reduce the temperature rise at the center of the cell. For this reason, it is not necessary to provide a pipe or the like for flowing the refrigerant inside the battery. Therefore, a temperature rise can be suppressed with a compact structure. Furthermore, it is possible to easily cool the inside of the battery by cooling the exterior body. For this reason, it becomes possible to suppress a temperature rise effectively.

  The second electrode is in contact with and electrically connected to the current collector. On the other hand, the first electrode is not in contact with the current collector. The positive and negative electrodes and the separator have a hole through which the current collector passes in the central portion thereof. A rod-shaped current collector passes through the hole. The diameter of the hole of the first electrode is larger than the outer diameter of the rod-shaped current collector. For this reason, the first electrode is not in contact with the current collector. The diameter of the hole of the second electrode is smaller than the outer diameter of the rod-shaped current collector. For this reason, the second electrode is in contact with and electrically connected to the current collector. The material of the current collector contains a metal. For this reason, the current collector functions as a terminal of the second electrode. Moreover, as a material of a collector, iron, aluminum, or what plated these on nickel is included.

  In the present fuel cell, the outer package may have a cylindrical metallic trunk. The exterior body may be a cylinder with a bottom with a lid. The said exterior body may have a cylindrical metallic trunk | drum and two cover parts which cover the axial direction opening part of the said trunk | drum. In this case, the current collector may penetrate through the lid.

  According to this configuration, the current collector may pass through the lid portion and be supported by both lid portions. The exterior body may be provided with lids at both end openings of a circular pipe (pipe). In this case, the exterior body has a sealed space formed by a circular tube and a lid therein. And the electrode group containing a positive / negative electrode and a separator is accommodated in this sealed space. The lid may be made of metal. The outer diameter of the first electrode may be made slightly larger than the inner diameter of the exterior body. The outer diameter of the second electrode is made smaller than the inner diameter of the exterior body.

  In the present fuel cell, the side portion of the exterior body may have a substantially cylindrical shape, and the exterior body may have a bulge portion that bulges in a dome shape at both ends in the axial direction.

According to this structure, the exterior body has the side part in which the bulging part was formed in one end, and the bulging part separate from the side part attached to the opening of the other end of the side part. May be. Or the exterior body may have the substantially cylindrical side part by which the axial direction both ends were opened, and the bulging part attached to the both ends.
In any case, the exterior body has a sealed space surrounded by the bulging part and the side part. Positive and negative electrodes and a separator are accommodated in the sealed space.

  The outer diameter of the first electrode is made slightly larger than the inner diameter of the exterior body. The outer diameter of the second electrode is made smaller than the inner diameter of the exterior body. With such a configuration, the heat generated in the first electrode is directly transmitted to the exterior body. The heat generated in the second electrode is transferred to the first electrode through one separator. As described above, in the present fuel cell, the heat generated by the electrode is efficiently transmitted to the exterior body. For this reason, a temperature gradient can be made small and the temperature rise in the center part of a laminated battery can be made small.

  The laminated battery according to the present invention may further include a hydrogen storage chamber for storing hydrogen gas generated in the negative electrode, which is provided in an inner space of the dome-shaped bulge portion of the exterior body.

  As described above, the present fuel cell and the fuel cell system using the same employ manganese dioxide as the positive electrode active material. Further, during overcharge, hydrogen gas and oxygen gas generated from the negative electrode and the positive electrode are stored as hydrogen gas state and oxygen gas state or oxygen dissolved in the electrolyte, respectively. Thereby, the chemical energy of hydrogen and oxygen can be reconverted into electric energy and used. Therefore, energy use efficiency and energy density can be dramatically increased. Further, it is not necessary to separately provide equipment for supplying hydrogen gas and oxygen gas.

Furthermore, electric energy is output through the electrode reaction of the secondary battery. Therefore, the followability with respect to the load fluctuation is greatly improved as compared with the conventional fuel cell. Further, in the charge / discharge reaction process at the positive electrode, trimanganese tetraoxide that becomes an irreversible substance does not occur. For this reason, the life characteristics can be greatly improved.
In addition, this fuel cell suppresses the temperature rise inside the cell and does not require an extra space for cooling.

It is sectional drawing which shows typically the structure of the reversible fuel cell which concerns on 1st Embodiment of this invention, and is the example which oxygen dissolved in electrolyte solution. It is a modification of the reversible fuel cell of 1st Embodiment of this invention. It is sectional drawing which shows the structure of the fuel cell which concerns on 2nd Embodiment of this invention. It is drawing which shows the DD cross section of FIG. 2A. It is sectional drawing which shows the structure of the 2nd modification of the fuel cell which concerns on 2nd Embodiment of this invention. It is drawing which shows the structure of the battery module which consists of a fuel cell which concerns on the modification shown in FIG. 3, and the part enclosed with the circle in the figure is a principal part enlarged view. It is a front view of the current collecting plate in FIG. 4A. It is sectional drawing which shows the structure of the 3rd modification of the fuel cell which concerns on 2nd Embodiment of this invention. In FIG. 5A, the modification of the shape of the connection part of a fuel cell is shown. FIG. 5A shows another modification of the shape of the connecting portion of the fuel cell. It is drawing which shows the structure of the battery bank which consists of a fuel cell which concerns on the modification shown to FIG. 5C. It is sectional drawing which shows a structure when the fuel cell which concerns on 3rd Embodiment of this invention is comprised as a unit cell. FIG. 7B is an assembled cross-sectional view showing a structure when the unit battery of FIG. 7A is assembled into a module. It is drawing which shows the structure of the battery bank formed by connecting multiple fuel cells shown to FIG. 7B. FIG. 8B is a connection diagram of fuel cells in the battery bank of FIG. 8A. It is a partially broken side view which shows the structure of the reversible fuel cell which concerns on 4th Embodiment of this invention. It is an AA cross section of FIG. 9A. It is a cross-sectional view which shows typically the structure of the electrode part of the reversible fuel cell which concerns on 4th Embodiment of this invention. It is a systematic diagram for demonstrating the electric power generation process using the reversible fuel cell which concerns on 4th Embodiment of this invention. It is a cross-sectional view showing the structure of a reversible fuel cell according to a fifth embodiment of the present invention. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is a systematic diagram which shows the relationship between the reversible fuel cell which concerns on 5th Embodiment of this invention, and an external system. It is a systematic diagram for demonstrating the electrolyte treatment process using the reversible fuel cell which concerns on 5th Embodiment of this invention. It is a schematic block diagram of the cylindrical laminated fuel cell which concerns on 6th Embodiment of this invention, and is a figure which shows an axial cross section. It is a schematic block diagram of the modification of the cylindrical laminated fuel cell which concerns on 6th Embodiment of this invention, and is an axial sectional view. It is a schematic block diagram which shows the donut battery which concerns on 7th Embodiment of this invention. It is a graph which shows the discharge characteristic (in the case of one electron reaction) of a manganese dioxide positive electrode. It is a graph which shows the discharge characteristic (in the case of a two-electron reaction) of a manganese dioxide positive electrode. It is a graph which shows the result of a XRD measurement, and this measurement is a measurement which investigates the change according to the difference in the depth of discharge of the composition in a manganese dioxide positive electrode. It is a graph which shows an experimental result when a manganese dioxide electrode is charged with oxygen gas. It is a graph which shows the other experimental result when a manganese dioxide electrode is charged with oxygen gas. It is a characteristic graph which shows typically the relation between the composition of the positive electrode and the terminal voltage. It is the graph which calculated | required the influence by the pressure of free energy by the thermodynamic calculation.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. The voltage of one fuel cell is as low as several volts or less. For this reason, when a high voltage is required, a plurality of fuel cells are connected in series with each other and used as a module. A system including a combination of a fuel cell and other equipment is referred to as a fuel cell system.

  Before describing individual embodiments, matters common to these embodiments will be described. That is, first, a negative electrode, a positive electrode, an electrolytic solution, and a separator will be described. Thereafter, individual embodiments are described.

<Negative electrode>
The negative electrode used in the reversible fuel cell of the present invention contains a hydrogen storage material. The hydrogen storage material may be any material that can store and release hydrogen, and is not limited to a hydrogen storage alloy. In addition to the hydrogen storage alloy, the hydrogen storage material may be a material that adsorbs hydrogen on the catalyst surface, such as a hydrogenation catalyst. Examples of the hydrogenation catalyst include Ni, Fe, Ti, Al, Ga, As, Se, Mg, Sb, Te, Tl, Pd, Sc, Bi, Ca, V, Cr, Mn, Co, Cu, Zn, and Ru. A metal or an alloy containing one or more selected from The hydrogen storage material may be a metal or an alloy containing one or more selected from Ni, Fe, Ti, Pd, Sc, V, Mn, and Co. These metals or alloys have alkali resistance and an excellent hydrogen dissociation adsorption rate.

  The hydrogen storage material may be a hydrogen storage alloy from the viewpoint of the hydrogen storage amount. The material of the hydrogen storage alloy may be a commonly used material such as Mm (Misch metal), Ni, Co, Mn, or Al-based AB5 type alloy. Further, this material may be an AB2 type alloy containing a transition metal containing nickel as a main component and a rare earth metal having a higher content. Further, this material may be an AB3 type alloy, an A2B7 type alloy, a Ti—Fe alloy, a V alloy, an Mg alloy, or a Pd alloy.

  The average particle size of the hydrogen storage alloy contained in the negative electrode may be in the range of 5 to 100 μm, and more preferably in the range of 10 to 50 μm. When the average particle size of the hydrogen storage alloy is less than 5 μm, the specific surface area of the alloy particles increases. For this reason, the particle | grain surface of a hydrogen storage alloy becomes easy to be corroded by an alkali. Such corrosion causes a decrease in the hydrogen storage amount and a decrease in the utilization rate of the hydrogen storage alloy in the negative electrode. Furthermore, since the conductivity is also deteriorated, the discharge characteristics of the battery are deteriorated. When the average particle diameter exceeds 100 μm, the specific surface area of the particles becomes small. For this reason, the hydrogen storage / release reaction in the negative electrode is delayed. For this reason, the discharge characteristic of a battery deteriorates. In the first embodiment to be described later, the average particle size of the hydrogen storage alloy contained in the negative electrode is 20 μm.

  In general, an oxide film that causes a decrease in capacity and / or impurities that do not contribute to a charge / discharge reaction are present on the particle surface of the hydrogen storage alloy. For this reason, the hydrogen storage alloy may be activated. This activation treatment method includes, for example, a surface modification treatment method including acid treatment of the hydrogen storage alloy and removal of an oxide film present on the surface of the alloy particles. The activation treatment method includes a surface modification treatment method using an alkali treatment. In addition, the method using an acid treatment includes a water washing process as a post process. This water washing process is a process for removing the processing liquid adhering to the hydrogen storage alloy. On the other hand, the surface modification treatment method using alkali treatment is a surface modification treatment method with a small number of steps since this water washing step is not included. If a high-temperature alkaline aqueous solution is used, the treatment effect is improved. In the first embodiment to be described later, a surface modification treatment method using alkali treatment is employed.

The hydrogen storage alloy may be a hydrogen storage alloy represented by a general composition formula RE _(1-x) Mg _x Ni _y Al _z . When a hydrogen storage alloy having the above composition formula is used, a better negative electrode can be obtained than when a conventional AB5 system is used. This negative electrode has a low self-discharge, a high capacity retention rate, a high discharge voltage, and good high rate discharge characteristics. Furthermore, this negative electrode does not require activation by acid treatment or alkali treatment as described above. The crystal structure of the hydrogen storage alloy having the above composition has a superlattice phase. Here, RE in the formula is at least one element selected from the group consisting of La, Ce, Pr and Nd. The subscripts x, y, and z are in the ranges indicated by 0.01 ≦ x ≦ 0.2, 4.0 ≦ y ≦ 4.9, and 0.05 ≦ z ≦ 0.3, respectively.

  When the total of the hydrogen storage alloy powder, binder, and conductive additive added as necessary is 100% by weight, the weight ratio of the hydrogen storage alloy in the negative electrode is in the range of 80 to 99.8%. It may be within.

  The negative electrode includes a paste-type negative electrode and a non-paste-type negative electrode. In the manufacture of the paste type negative electrode, the paste is formed by mixing the hydrogen storage alloy powder, the binder, and the conductive powder added as necessary. This paste is applied and filled into a current collector and dried. Then, a negative electrode is manufactured by rolling a collector with a roller press etc. In the production of the non-paste type negative electrode, the hydrogen storage alloy powder, the binder, and the conductive powder added as necessary are stirred. The powder obtained by stirring is spread on a current collector. Then, a negative electrode is manufactured by carrying out current collector rolling with a roller press etc.

  Examples of the binder used for the negative electrode include sodium polyacrylate, methyl cellulose, carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), ethylene-vinyl alcohol, ethylene vinyl acetate copolymer (EVA). ), Polyethylene (PE), polypropylene (PP), styrene butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), xanthan gum, guar gum, and peptin. When the total of the hydrogen storage alloy powder, the binder, and the conductive additive added as necessary is 100% by weight, the weight ratio of the binder blended in the negative electrode is 0.1 to 10% by weight. % Is preferable.

  The conductive auxiliary agent for negative electrode should just be the powder which has electroconductivity. The conductive aid may be a carbon powder such as graphite powder, acetylene black, and ketjen black. Further, the conductive auxiliary agent may be a metal powder such as nickel powder, copper powder and cobalt powder. When the total of the hydrogen storage alloy powder, the binder, and the conductive auxiliary agent added as necessary is 100% by weight, the weight ratio of the conductive auxiliary compounded in the negative electrode is 0.1 to 10% by weight. % Is preferable.

  The negative electrode current collector may be a two-dimensional substrate such as a punching metal, an expanded metal, and a wire mesh. Further, the negative electrode current collector may be a three-dimensional substrate such as a foamed nickel substrate, a reticulated sintered fiber substrate, or a felt-plated substrate that is a metal-plated nonwoven fabric. However, when producing a non-paste type hydrogen storage alloy electrode, a mixture containing hydrogen storage alloy powder is dispersed. For this reason, a two-dimensional substrate may be used as the conductive substrate.

<Positive electrode>
The positive electrode contains manganese dioxide as an active material. The average particle diameter of the positive electrode active material may be in the range of 1 to 100 μm, and preferably in the range of 10 to 50 μm. When the average particle diameter of the positive electrode active material is less than 1 μm, the specific surface area of the positive electrode active material particles is increased. For this reason, the amount of the binder for binding the particles to each other increases. This leads to a decrease in the active material content ratio of the positive electrode composition and a decrease in the positive electrode capacity. Furthermore, since the conductivity is also deteriorated, the discharge characteristics of the battery are deteriorated. When the average particle size exceeds 100 μm, the charge rate due to the contact between the oxygen-containing electrolyte and the positive electrode active material tends to decrease due to the oxygen diffusion rate limiting. In addition, the specific surface area of the particles is reduced. This hinders the charge / discharge reaction of the positive electrode and deteriorates the discharge characteristics of the battery. Moreover, since the electrode is not dense, the energy density is lowered. In the first embodiment to be described later, the positive electrode active material is manganese dioxide having an average particle diameter of 10 μm.

  When the total of the positive electrode active material, the binder, and the conductive auxiliary agent added as necessary is 100% by weight, the weight ratio of the positive electrode active material blended in the positive electrode is 20 to 99.8% by weight. It may be within the range. When the weight ratio of the positive electrode active material is less than 20% by weight, trimanganese tetraoxide, which is an irreversible component, is easily generated in the positive electrode during rapid discharge. On the other hand, when the weight ratio of the positive electrode active material exceeds 99.8% by weight, it is difficult to manufacture an electrode.

The positive electrode active material is usually a composite of manganese dioxide particles and a conductive material covering the surface. The conductive material may be a metal material, a carbon material, a conductive ceramic, or a conductive polymer. In addition, this material may be a carbon material from the viewpoint of conductivity and alkali resistance. The carbon material is not particularly limited as long as it has conductivity. The carbon material includes, for example, ketchin black (KB), acetylene black (AB), furnace black, graphite, graphene, fibrous carbon, glass carbon, and activated carbon. The specific surface areas of KB and AB are preferably 50 to 3000 m ² / g.

  Normally, when carbon is used as a conductive material, the carbon is oxidized to carbon dioxide, and the conductivity cannot be maintained. However, the inside of the fuel cell is under a hydrogen atmosphere. For this reason, carbon is not oxidized and can maintain conductivity.

  The thickness of the coating film of the carbon coating may be within a range of 0.01 to 5 μm, for example. When the thickness of the carbon coating film is less than 0.01 μm, the improvement in conductivity is insufficient. For this reason, current concentration on the active material surface is likely to occur during charging and discharging. For this reason, it becomes difficult to improve the high rate charge / discharge characteristics. On the other hand, when the thickness of the carbon coating film exceeds 5 μm, the electrode capacity density may be reduced. The coverage of the carbon coating film is preferably 0.1 to 20% by weight with respect to 100% by weight of the positive electrode active material. When the coverage is less than 0.1% by weight, the improvement in conductivity is insufficient. For this reason, current concentration on the active material surface is likely to occur during charging and discharging. For this reason, it becomes difficult to improve the high rate charge / discharge characteristics. On the other hand, when the coverage exceeds 20% by weight, there arises a problem that the electrode capacity density is lowered. A preferable lower limit of the coverage is 0.2% by weight, and a more preferable lower limit is 0.5% by weight. Moreover, the upper limit with preferable coverage is 5 weight%, and a more preferable upper limit is 2 weight%.

  The conductive treatment method may be any method that can form a carbon coating film on the surface of the positive electrode active material particles. This method includes known techniques such as sputtering, vapor deposition, mechanical milling, heating, electroless plating, and spray drying. Among these, the mechanical milling method and the heating method can form a carbon coating with excellent uniformity by a simple method without using a large-scale apparatus. For example, the mechanical milling method includes applying mechanical energy to the powder particles and causing strong surface fusion between the particles by a mechanochemical reaction on the particle surface. This method is a technique for obtaining a fine particle composite material, and is a method of coating the particle surface of the active material powder with carbon. The mechanical milling method may be performed in a hydrogen atmosphere. Under a hydrogen atmosphere, it becomes easy to form a carbon coating film on the surface of the positive electrode active material particles.

  The heating method includes heat treatment such as mixing the positive electrode active material and the carbon precursor, and heating in a non-oxidizing atmosphere. As a result, a carbon film is formed. In the heat treatment, for example, a carbon precursor gas such as butane gas is held in a heat treatment furnace such as a rotary kiln maintained at 400 to 2000 ° C. in a non-oxidizing gas atmosphere for 0.1 to 5 hours. If the heat treatment temperature is less than 400 ° C., it is difficult to realize carbonization, and the conductivity improving effect of the positive electrode active material may be reduced. On the other hand, if the heat treatment temperature exceeds 2000 ° C., the apparatus becomes large. For this reason, not only the cost is increased, but the active material may be damaged. Further, when the heat treatment time is less than 0.1 hour, it may be difficult to coat the carbon uniformly. On the other hand, when the heat treatment time exceeds 5 hours, the heat source is driven for a long time. For this reason, the cost may increase. The heat treatment atmosphere is not limited to butane gas, but may be methane gas, ethane gas, propane gas, or a mixed gas thereof. The heat treatment atmosphere may be, for example, carbon precursor gas diluted with nitrogen, helium, neon, argon, hydrogen, carbon dioxide, or a mixed gas thereof.

  In the manufacture of the positive electrode, the paste is formed by mixing the positive electrode active material powder, the binder, and conductive powder added as necessary. This paste is applied and filled into a current collector and dried. Then, a positive electrode is manufactured by rolling a current collector with a roller press or the like.

  Examples of the binder for the positive electrode include sodium polyacrylate, polytetrafluoroethylene (PTFE), methyl cellulose, carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), ethylene-vinyl alcohol, and ethylene acetate. Including vinyl copolymer (EVA), polyethylene (PE), polypropylene (PP), and styrene-ethylene-butylene-styrene copolymer (SEBS). Of these, polytetrafluoroethylene (PTFE) is fiberized by stirring. For this reason, it is possible to fix positive electrode active material powder and the conductive support agent added as needed in mesh shape. The weight ratio of the binder to be mixed with the positive electrode is 0.1 to 20% when the total of the positive electrode active material powder, the binder, and the conductive additive added as necessary is 100% by weight. % May be within the range.

The conductive additive for positive electrode may be a powder that maintains conductivity without being oxidized at the positive electrode potential. The conductive aid may be, for example, a powder of carbon, nickel, cobalt hydroxide (Co (OH) ₂ ), cobalt monoxide (CoO), cobalt, or the like. The weight ratio of the conductive auxiliary compounded in the positive electrode is 0.1 to 60% when the total of the positive electrode active material powder, the binder, and the conductive auxiliary agent added as necessary is 100% by weight. It is preferable to mix in the range of%.

  The positive electrode current collector may be, for example, a two-dimensional substrate such as a metal foil, a punching metal, an expanded metal, and a wire mesh. Further, the positive electrode current collector may be a three-dimensional substrate such as a foam metal substrate, a reticulated sintered fiber substrate, or a felt-plated substrate that is a metal-plated nonwoven fabric. When the current collector for the positive electrode is a punching metal, a three-dimensional substrate, or a foam metal substrate, a sufficient current collecting property can be obtained, and a positive electrode having a structure in which the oxygen-dissolved electrolyte can easily be immersed is obtained.

  Charging the positive electrode can be realized by bringing the positive electrode into contact with an oxygen-dissolved electrolyte. When the thickness of the positive electrode is too large, the oxidation rate (charging rate) of the positive electrode becomes oxygen diffusion rate limiting and tends to decrease. Therefore, the thickness of the positive electrode varies depending on the concentration of oxygen dissolved in the electrolytic solution, but may be in the range of 50 to 2000 μm. When the thickness of the positive electrode is less than 50 μm, the positive electrode capacity becomes small. When the thickness of the positive electrode exceeds 2000 μm, oxygen diffusion becomes insufficient, and there is a possibility that a portion that is not oxidized remains in the positive electrode.

<Electrolyte>
The electrolytic solution used in the present invention is preferably an oxygen-dissolved electrolytic solution in which oxygen is dissolved in a range of 0.02 to 200 g / L in the electrolytic solution. When the oxygen concentration dissolved in the electrolytic solution is less than 0.1 g / L, it takes time to oxidize the positive electrode active material because the oxygen concentration is low. When the oxygen concentration exceeds 200 g / L, the corrosiveness of the electrolytic solution is increased, so that the negative electrode is damaged.

  Adjustment of the dissolved oxygen concentration in electrolyte solution may raise the concentration of dissolved oxygen by adding hydrogen peroxide to electrolyte solution. Alternatively, in this adjustment, the dissolved oxygen concentration may be increased by increasing the hydraulic pressure of the electrolyte according to Henry's law. For example, if oxygen is sealed at a hydraulic pressure of 100 MPa, about 26 g of oxygen can be dissolved in 1 liter of electrolyte.

  However, in a method of increasing the concentration of dissolved oxygen by adding hydrogen peroxide to the electrolyte, a high concentration of hydrogen peroxide is used. High concentrations of hydrogen peroxide have strong corrosive properties, and thus easily generate peroxides when in contact with combustible materials. For this reason, you may adjust a dissolved oxygen concentration by raising the liquid pressure of electrolyte solution. In that case, the liquid pressure of the electrolytic solution is preferably 0.1 MPa to 10 GPa. By using a high-pressure or ultrahigh-pressure electrolytic solution, it is possible not only to increase the dissolved oxygen concentration, but also to dissolve oxygen gas generated during overcharging in the electrolytic solution. In addition, the operating voltage of the battery can be increased.

  Said oxygen-dissolved electrolyte can oxidize (charge) a positive electrode active material by contacting with a positive electrode. If the oxygen-dissolved electrolyte is set to a high pressure or an ultrahigh pressure, the oxygen gas generated during charging is dissolved in the electrolyte. For this reason, a space for storing oxygen gas becomes unnecessary, and the dissolved oxygen concentration in the electrolytic solution can be increased.

  Regarding the above-described hydraulic pressure range of the electrolytic solution, if the hydraulic pressure of the electrolytic solution is less than 0.1 MPa, it is difficult to increase the dissolved oxygen concentration in the electrolytic solution. For this reason, not only does it take time to oxidize the positive electrode active material, but it also becomes difficult to effectively dissolve the oxygen gas generated during charging in the electrolytic solution. It is substantially difficult to set the liquid pressure of the electrolytic solution to an ultrahigh pressure exceeding 10 GPa.

  The electrolytic solution used in the present invention may be a commonly used alkaline aqueous solution. From the viewpoint of suppressing elution of the alloy component into the electrolyte, for example, an alkaline substance such as lithium hydroxide (LiOH), sodium hydroxide (NaOH), or potassium hydroxide (KOH) may be used alone. Two or more kinds may be used in combination. The concentration of the alkaline substance in these electrolytic solutions is preferably 1 to 10 mol / L, and more preferably 3 to 8 mol / L.

  A thickener may be dissolved in the electrolytic solution. Since the electrolyte solution in which the thickener is dissolved has a high viscosity, the oxygen diffusion rate is slow. By slowing down the oxygen diffusion rate, it is difficult for the negative electrode and oxygen to come into contact with each other, so that the self-discharge reaction of the negative electrode can be reduced. In addition, since the viscosity of the electrolytic solution is increased, the liquid leakage resistance is also improved. The material of the thickener may be any material that has water absorption and increases the viscosity of the electrolytic solution. This material includes, for example, resins such as polyacrylate, polystyrene sulfonate, polyvinyl sulfonate, gelatin, starch, polyvinyl alcohol (PVA), and fluororesin.

  The thickener may be a polyacrylate from the viewpoints of high water absorption, high water retention, high gelling power, and alkali resistance. Specific examples of the polyacrylate include lithium polyacrylate, sodium polyacrylate, and potassium polyacrylate. These may be used individually by 1 type, or may use 2 or more types together.

  The weight ratio of the thickener is preferably in the range of 0.1 to 30% by weight, more preferably 1 to 20% by weight, when the total of the electrolytic solution and the thickener is 100% by weight. When the weight ratio of the thickener exceeds 30% by weight, the electrolyte solution viscosity is too high, so that the active material and the electrolyte solution are difficult to contact. For this reason, not only proton conductivity is lowered, but also the electrolytic solution is difficult to circulate. When the weight ratio of the thickener is less than 0.1% by weight, a sufficient effect due to the addition of the thickener cannot be obtained.

<Separator>
The separator used in the present invention is preferably a separator that allows protons to pass therethrough but hardly passes oxygen gas. Examples of the separator material include polyolefins such as polyethylene (PE), polypropylene (PP), polybutene (PB), and ethylene propylene rubber, resins such as polyphenylene sulfite, polyfluoroethylene, polyamide, polyimide, polyamideimide, and Nafion. Including. These may be used alone or in combination of two or more.

  The separator may contain inorganic particles in addition to the resin. The weight ratio of the inorganic particles is preferably in the range of 10 to 80% by weight when the total of the resin and the inorganic particles is 100% by weight. The inorganic particles may be oxide ceramics such as alumina, titania, zirconia, magnesia, ceria, yttria and iron oxide. Furthermore, the inorganic particles may be nitride ceramics such as titanium nitride and boron nitride. Further, the inorganic particles are ceramics such as aluminum sulfate, aluminum hydroxide, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amicite, bentonite, zeolite, etc. Alternatively, glass fiber or the like may be used. These may be used singly or in combination of two or more. By including inorganic particles in the resin, not only the liquid immersion property and electrochemical stability are improved, but also the meltdown of the separator due to heat is suppressed.

  The separator may be, for example, a fibrous aggregate such as a woven fabric and a non-woven fabric, or may be a film like a microporous membrane. The separator may be in the form of a sheet in which these layers are laminated.

  When the separator is a microporous membrane, the pore size is preferably in the range of 0.1 to 10 μm. In the present embodiment, it is preferable to use a polypropylene microporous film (thickness 20 μm, average pore diameter 0.2 μm) as a separator. When a separator having a thickness of 20 μm and an average pore diameter of 20 μm is used, the probability of short-circuiting is increased. The method for obtaining the average pore diameter of the separator includes taking a photograph with a magnification of 5000 times with a scanning electron microscope (SEM) and extracting only 30 pore diameters on the outermost surface. The separator may be formed as a water seal separator wetted with an electrolyte or water. The water seal separator has high gas impermeability. By using the water-sealed separator, it is possible to more reliably prevent hydrogen gas and oxygen gas from contacting and reacting with each other through the separator.

  Hereinafter, the present invention will be described more specifically based on more detailed embodiments. Note that the present invention is not limited to these embodiments.

(First embodiment)
1A and 1B are cross-sectional views schematically showing the structure of a reversible fuel cell C1 (hereinafter simply referred to as a cell C1) according to the first embodiment having the basic configuration of a fuel cell. The battery C1 uses the chemical energy of hydrogen and oxygen by converting it into electrical energy. Further, the battery C1 can store electrical energy converted into chemical energy. The battery C1 includes a negative electrode 4, a positive electrode 6, a negative electrode case 1, and a positive electrode case 2 as main elements. The negative electrode 4 and the positive electrode 6 are opposed to each other with the separator 5 interposed therebetween. The negative electrode case 1 has a hydrogen storage chamber 8. The positive electrode case 2 has an oxygen storage chamber 7.

The negative electrode active material of the negative electrode 4 includes a hydrogen storage alloy represented by La _0.54 Pr _0.18 Nd _0.18 Mg _0.1 Ni _4.5 Al _0.1 . In the manufacture of the negative electrode 4, a slurry-like composite material having a weight ratio of 97: 1: 1: 1 is adjusted using AB, CMC, and SBR. Further, this slurry-like composite material is applied to a punching metal obtained by nickel-plating a steel material.

  The positive electrode active material of the positive electrode 6 contains manganese dioxide. In the manufacture of the positive electrode 6, a slurry-like mixture is prepared using AB, CMC, and PTFE so that the weight ratio thereof is 97: 0.5: 2: 0.5. Further, this slurry-like composite material is filled in the foamed nickel. Note that manganese dioxide as the positive electrode active material is previously charged in a rotary kiln (700 ° C., 1 hour, butane gas atmosphere). Thereby, a conductive thin film is formed on manganese dioxide. The coverage of the conductive film (carbon coating film) is obtained by heat-treating the obtained manganese dioxide in an oxygen atmosphere and calculating the weight difference before and after the heat treatment of manganese dioxide. The coverage of the carbon coating film is 0.9% by weight with respect to 100% by weight of manganese dioxide.

  The separator 5 includes a microporous membrane made of polypropylene (thickness 20 μm, average pore diameter 0.2 μm). The separator 5 holds the electrolytic solution 3.

  The electrolytic solution 3 contains a 6 mol / L potassium hydroxide aqueous solution. Furthermore, the electrolytic solution 3 contains 5% by weight of sodium polyacrylate as a thickener.

As shown in FIG. 1A, a negative electrode 4 and a positive electrode 6 have a structure in which a separator 5 is sandwiched. The surface of the negative electrode 4 that is not in contact with the separator 5 is airtightly covered with the box-shaped negative electrode case 1. An inner space formed by the negative electrode 4 and the negative electrode case 1 constitutes a hydrogen storage chamber 8. The hydrogen storage chamber 8 directly stores the hydrogen gas generated at the negative electrode without requiring an additional member such as a booster. Further, the hydrogen storage chamber 8 is provided in contact with the negative electrode 4. For this reason, it is possible to supply hydrogen gas directly to the negative electrode 4 without interposing a communication path or an additional member.

  The surface of the positive electrode 6 that is not in contact with the separator 5 is covered with the box-shaped positive electrode case 2. The inner space formed by the positive electrode 6 and the positive electrode case 2 constitutes an oxygen storage chamber 7 for storing oxygen. The oxygen storage chamber 7 stores the electrolytic solution 3 having a high hydraulic pressure (for example, 10 MPa). For this reason, the oxygen gas generated at the positive electrode 6 is dissolved in the electrolytic solution and stored in the oxygen storage chamber 7 as dissolved oxygen. That is, the oxygen gas generated in the positive electrode 6 is directly stored in the oxygen storage chamber 7 without requiring an additional member such as a booster. The oxygen storage chamber 7 is provided in contact with the positive electrode 6. For this reason, it is possible to supply oxygen directly to the positive electrode 6 without interposing a communication path or an additional member.

  The hydrogen storage chamber 8 and the oxygen storage chamber 7 are separated by a wall member 9 having mobility. Wall member 9 includes positive electrode 4 and negative electrode 6, and separator 5. The wall member 9 may be a flexible member.

  The surface of the negative electrode 4 in contact with the hydrogen storage chamber 8 contains a lot of hydrophobic material. Thereby, the hydrogen storage alloy of the negative electrode 4 can contact with hydrogen gas, without getting wet. Moreover, the surface which contacts the separator 5 of the negative electrode 4 has hydrophilicity. Thus, this surface prevents hydrogen gas from passing through the negative electrode 4. This surface is almost always wet with the electrolyte. Thereby, the ionic conductivity of the negative electrode 4 is ensured.

  The operation of the battery C1 configured as described above will be described below. The battery C1 includes a positive electrode 6 having a positive electrode active material and a negative electrode 4 having a negative electrode active material. For this reason, at the time of initial charge, it is stored as electric energy in the electrode of the battery C1. In the present specification, for convenience of description, charging exceeding the electric capacity of the active material in the electrode may be referred to as overcharging. In the overcharged state, oxygen gas and hydrogen gas are generated.

  If the current is continued to be supplied after the electrode of the battery C1 is initially charged, hydrogen gas is generated from the negative electrode 4 and oxygen gas is generated from the positive electrode 6. Hydrogen gas is stored in the hydrogen storage chamber 8. As charging proceeds, the pressure inside the hydrogen storage chamber 8 increases. For this reason, the hydrogen storage chamber 8 expands under the influence of the hydrogen gas pressure. The hydrogen storage chamber 8 and the oxygen storage chamber 7 are partitioned by a wall member 9 having mobility. For this reason, when the hydrogen storage chamber 8 expands, the wall member 9 is displaced or deformed, and the electrolyte 3 in the oxygen storage chamber 7 is compressed. The deformation of the wall member 9 continues until the pressures in the hydrogen storage chamber 8 and the oxygen storage chamber 7 are substantially equalized. In this way, the electrolytic solution 3 in the oxygen storage chamber 7 becomes a high pressure. As a result, the oxygen gas generated from the positive electrode 6 is dissolved in the electrolytic solution 3. Thereby, the electrolyte solution 3 becomes an oxygen-dissolved electrolyte solution.

  The electrolyte 3 of the fuel cell can have a liquid pressure in the range of 0.1 MPa to 10 GPa. In the battery C1 of the present embodiment, the electrolytic solution 3 has a hydraulic pressure in the range of 1 MPa to 10 MPa.

When the battery C1 is discharged, a discharge reaction as a secondary battery occurs between the negative electrode 4 and the positive electrode 6. Thereby, a current flows through the load. At this time, the amount of electricity of the negative electrode 4 and the positive electrode 6 decreases due to discharge. The reduced amount of electricity in the negative electrode 4 and the positive electrode 6 is compensated by charging with hydrogen gas and oxygen stored in the hydrogen storage chamber 8 and the oxygen storage chamber 7. That is, in the negative electrode 4, the reaction represented by the chemical formula (2) occurs. As a result, the protons released from the charged hydrogen storage alloy (MH) are supplemented with hydrogen gas. Thereby, the charged state of the negative electrode is maintained. On the other hand, in the positive electrode 6, the reaction represented by the chemical formula (4) occurs. As a result, the manganese oxyhydroxide generated by reducing the charged manganese dioxide (MnO ₂ ) is oxidized again by oxygen. Thereby, the charge state of a positive electrode is maintained. That is, manganese dioxide functions as a catalyst for the reaction at the positive electrode. On the other hand, the hydrogen storage alloy functions as a catalyst for the reaction in the negative electrode.

Manganese dioxide in the positive electrode 6 is reduced to manganese oxyhydroxide when discharged. Manganese oxyhydroxide is oxidized by oxygen in the electrolyte and returns to manganese dioxide. Therefore, manganese dioxide is almost always present in the positive electrode 6. For this reason, the positive electrode SOC (state of charge; State
of Charge) is maintained at almost 100%. The positive electrode 6 faces the oxygen storage chamber 7 and is always in contact with oxygen. For this reason, the discharge reaction of manganese dioxide does not proceed until the manganese dioxide becomes manganese hydroxide, and trimanganese tetraoxide (Mn ₃ O ₄ ), which is an irreversible component, is not generated. Therefore, since the deterioration of the positive electrode 6 is suppressed, its life characteristics are greatly improved.

  The hydrogen storage alloy in the negative electrode 4 releases protons during discharge. For this reason, the hydrogen content of the hydrogen storage alloy decreases. However, the negative electrode 4 faces the hydrogen storage chamber 8 and is always in contact with hydrogen gas. Therefore, the protons released from the hydrogen storage alloy (MH) are supplemented by hydrogen gas. As a result, the hydrogen storage alloy that has released hydrogen returns to the state of storing hydrogen. Therefore, in the negative electrode 4, there is almost always an alloy that occludes hydrogen. As a result, the SOC of the negative electrode is maintained at almost 100%.

FIG. 22 is a graph schematically showing the relationship between the potential (vertical axis) of the manganese dioxide electrode and the SOC (horizontal axis). As shown in FIG. 22, the potential of the battery C1 is in the vicinity of the high potential indicated by manganese dioxide (MnO ₂ ). That is, the battery C1 maintains a high discharge potential.

  The battery C1 according to the present embodiment stores the electrical energy supplied during overcharge in the storage chambers 7 and 8 as chemical energy. The battery C1 can use the stored chemical energy by reconverting it into electrical energy. Therefore, unlike the conventional secondary battery, the electric capacity of the battery C1 is not limited by the amount of the active material. Therefore, the amount of hydrogen gas stored per volume and the amount of dissolved oxygen can be increased by increasing the pressure resistance and sealing performance of the storage chambers 7 and 8 and the battery C1. Thereby, the energy density of the battery C1 can be significantly improved (for example, several tens of times) as compared with the conventional secondary battery. Moreover, the hydrogen gas generated at the negative electrode 4 or the oxygen gas generated at the positive electrode 6 is directly stored in the storage chambers 7 and 8 during overcharge. For this reason, there is no need to provide an additional gas booster or communication passage. Therefore, since the battery C1 has a simple structure, it can be manufactured and supplied at low cost. In particular, oxygen gas is dissolved and stored in the electrolyte. For this reason, the safety regarding handling of oxygen gas is dramatically improved.

  Furthermore, as described above, when the battery C1 is discharged, electric energy is output by the reactions shown in the equations (1) and (3). For this reason, as compared with the conventional fuel cell, the followability to the load and the power are greatly improved. Thereby, the battery C1 can be used for an application with a large load fluctuation that requires instantaneous high output, such as a vehicle. At this time, the battery C1 can be used alone without the need for an additional secondary battery or a power storage device such as a capacitor.

(Modification of the first embodiment)
FIG. 1B is a cross-sectional view schematically showing the structure of a battery C1 ′ according to a modification of the first embodiment. Battery C1 ′ has substantially the same structure as battery C1 of the first embodiment. That is, the battery C1 ′ includes a negative electrode 4 ′ and a positive electrode 6 ′ facing each other through a separator 5 ′, a negative electrode case 1 ′ forming a hydrogen storage chamber 8 ′, and a positive electrode case 2 ′ forming an oxygen storage chamber 7 ′. , As a major component. The main differences are as follows. That is, the electrolytic solution 3 ′ in which oxygen is dissolved is stored in the oxygen storage chamber 7 ′ of the battery C1. On the other hand, the oxygen storage chamber 7 ′ of the battery C1 ′ holds oxygen gas and the electrolyte 3 ′. That is, the oxygen storage chamber 7 ′ partially holds the electrolyte 3 ′.

  The surface in contact with the hydrogen storage chamber 8 ′ of the negative electrode 4 ′ contains a lot of hydrophobic material. On the other hand, the surface of the negative electrode 4 ′ that contacts the separator 5 ′ has hydrophilicity. Further, the surface of the positive electrode 6 'that is in contact with the oxygen storage chamber 7' contains a large amount of hydrophobic material. Thereby, the manganese dioxide of the positive electrode 6 ′ can come into contact with oxygen gas without getting wet. The surface of the positive electrode 6 'that contacts the separator 5' has hydrophilicity. As a result, this surface prevents oxygen gas from passing therethrough. This surface is almost always wet with the electrolyte. Thereby, the ionic conductivity of the positive electrode 6 'is ensured. The surfaces of the electrodes 4 ′ and 6 ′ on the gas storage chambers 8 ′ and 7 ′ side may be coated or sprayed with hydrophobic carbon or Teflon. Moreover, the surface which contacts the separator 5 'of electrodes 4' and 6 'may be coated or sprayed with hydrophilic modified nylon. Furthermore, vinyl acetate having both hydrophilic and hydrophobic properties may be granulated and used as a binder.

  The separator 5 'holds the electrolytic solution 3'. Further, in the present embodiment, both surfaces of the separator 5 'are wetted with the electrolytic solution 3'. For this reason, the separator 5 ′ functions as a water seal separator. Thereby, the gas impermeability of the separator 5 'is enhanced. As a result, hydrogen gas and oxygen gas are more reliably prevented from contacting and reacting with each other through the separator 5 '.

  The hydrogen storage chamber 8 'and the oxygen storage chamber 7' are configured not to communicate with each other. The oxygen storage chamber 7 ′ is filled with an electrolyte of the same type as the electrolyte 3 ′ interposed between the positive and negative electrodes, about 1/3 of the volume of the oxygen storage chamber 7 ′.

  When the amount of the electrolyte 3 'filled in the oxygen storage chamber 7' is small, the amount of water to be electrolyzed is small. As a result, the amount of hydrogen gas and oxygen gas generated during overcharging is reduced. On the other hand, if the amount of the electrolytic solution is large, the gas storage volume decreases. From such a viewpoint, the amount of the electrolyte 3 ′ filled in the oxygen storage chamber 7 ′ is preferably in the range of 20 to 50% of the volume of the oxygen storage chamber 7 ′, and in the range of 25 to 40%. More preferably, it is within.

  The operation of the battery C1 'configured as described above will be described below. The battery C1 'can be charged with current as usual until it is fully charged as a secondary battery. When the battery C1 'reaches the fully charged state and continues to supply current, hydrogen gas is generated from the negative electrode 4' and oxygen gas is generated from the positive electrode 6 '. These hydrogen gas and oxygen gas are stored in the hydrogen storage chamber 8 'and the oxygen storage chamber 7' without contacting each other. Then, the negative electrode 4 ′ and the positive electrode 6 ′ are charged with hydrogen gas or oxygen gas stored in the storage chamber 8 ′ or 7 ′.

When the discharge of the battery C1 ′ is started, a normal discharge reaction as a secondary battery occurs between the negative electrode 4 ′ and the positive electrode 6 ′. Thereby, a current flows through the load. At this time, the amount of electricity of the negative electrode 4 ′ and the positive electrode 6 ′ decreases due to the discharge. The reduced amount of electricity in the negative electrode 4 ′ and the positive electrode 6 ′ is compensated by charging with hydrogen gas and oxygen gas stored in the hydrogen storage chamber 8 ′ and the oxygen storage chamber 7 ′. That is, in the negative electrode 4 ′, the protons released from the charged hydrogen storage alloy (MH) are supplemented with hydrogen gas. Thereby, the charged state of the negative electrode is maintained. On the other hand, in the positive electrode 6 ′, manganese oxyhydroxide (MnOOH) generated by reducing charged manganese dioxide (MnO ₂ ) is oxidized again by oxygen gas. Thereby, the charge state of a positive electrode is maintained. After the hydrogen gas and oxygen gas in the storage chambers 7 ′ and 8 ′ are consumed, the battery C1 ′ is discharged in the same manner as a normal secondary battery.

  That is, the battery C1 'according to the present embodiment can store energy in the electrode as a secondary battery by normal charging. Furthermore, the battery C1 'stores the electric energy supplied at the time of overcharging as gas in the storage chambers 7' and 8 '. The battery C1 'can reconvert the stored energy into electrical energy for use.

  Further, the battery C1 'has improved pressure resistance and sealing performance between the storage chambers 7' and 8 'and the battery C1' including them. Thereby, the gas storage amount per volume is increasing. As a result, the energy density of the battery C1 'can be significantly improved (for example, about several tens of times) as compared with the conventional secondary battery. In addition, in the storage chambers 7 ′ and 8 ′, hydrogen gas generated at the negative electrode 4 ′ or oxygen gas generated at the positive electrode 6 ′ is directly stored during overcharge. For this reason, there is no need to provide an additional gas booster or communication passage. Therefore, the battery C1 'has a simple structure and can be manufactured and supplied at low cost.

  Furthermore, as described above, when the battery C1 'is discharged, electric energy is output by the electrode reaction of the secondary battery. For this reason, as compared with the conventional fuel cell, the followability to the load and the power are greatly improved. Accordingly, the battery C1 'can be used for an application with a large load fluctuation that requires instantaneous high output, such as a vehicle. At this time, the battery C1 'can be used alone without requiring an additional secondary battery or a power storage device such as a capacitor.

(Second Embodiment)
Next, a battery C2 according to the second embodiment of the fuel cell will be described. The battery C2 has a battery structure that is excellent in pressure resistance and easy to handle. 2A and 2B are cross-sectional views showing the structure of the battery C2. 2B is a cross-sectional view taken along the line DD in FIG. 2A. The battery C2 has the same basic configuration as the battery C1 of the first embodiment described with reference to FIGS. 1A and B. However, the battery C2 has a tubular outer package 10 as shown in FIG. 2A. Thereby, the battery C2 has excellent pressure resistance performance and handling performance. Battery C2 has an increased energy density and is easy to handle. The negative electrode, the positive electrode, the separator, and the electrolytic solution, which are the basic elements of the battery C2 according to the present embodiment, are the same as those of the battery C1 according to the first embodiment, except as described below. It may have the substance and structure.

  As shown in FIG. 2A, more specifically, the outer package 10 formed in a tubular shape has a cylindrical portion 10a and a bottom portion 10b. The bottom portion 10b is the bottom of the exterior body 10 that follows one end of the cylindrical portion 10a. A negative electrode 14, a positive electrode 16, and a separator 15 interposed between the negative electrode 14 and the positive electrode 16 are accommodated inside the bottom portion 10 b. The negative electrode 14 and the positive electrode 16 are formed in a bottomed cylindrical shape. The negative electrode 14 and the positive electrode 16 have cylindrical peripheral walls 14a and 16a and bottom portions 14b and 16b. A positive electrode 16 is disposed inside the exterior body 10 via a radial space. A negative electrode 14 is disposed further inside the positive electrode 16 with a separator 15 interposed therebetween. In the battery C <b> 2, a space (radial space) between the outer package 10 and the positive electrode 16 forms an oxygen storage chamber 19. On the other hand, the space formed inside the negative electrode 14 constitutes the hydrogen storage chamber 18.

  The exterior body 10 is made of a conductive material, specifically, nickel-plated iron. The outer surface of the bottom portion 16 b of the positive electrode 16 is joined to the inner surface of the bottom portion 10 b of the exterior body 10. Thereby, the exterior body 10 functions as a positive electrode terminal of the battery C2. On the other hand, the disc-shaped negative electrode terminal 11 is joined to the right end portion 14c of the negative electrode 14 on the side opposite to the bottom portion 14b (right side in FIG. 2A). Specifically, the right end portion 14 c of the negative electrode 14 is disposed so as to protrude rightward from the right end surfaces 10 c and 16 c of the exterior body 10 and the positive electrode 16. An inner diameter surface 17a of a donut-shaped insulating member 17 is fitted to the outer peripheral surface of the right end portion 14c. The insulating member 17 covers the outer body 10 and the right end surfaces 10 c and 16 c of the positive electrode 16. Furthermore, the inner surface (the left surface in FIG. 2A) that is one surface of the negative electrode terminal 11 is joined to the right end portion 14 c of the negative electrode 14.

  The electrodes 14 and 16 have flexibility. For this reason, when the hydrogen storage chamber 18 becomes high pressure due to generation of hydrogen gas due to overcharging, the pressure of the hydrogen storage chamber 18 is transmitted to the oxygen storage chamber 19. As a result, the electrolytic solution 13 in the oxygen storage chamber 19 is compressed to a high pressure. The electrolytic solution having a high pressure can dissolve more oxygen therein.

  Here, the surface of the negative electrode 14 in contact with the hydrogen storage chamber 18 contains a large amount of hydrophobic material. Thereby, the hydrogen storage alloy of the negative electrode 14 can contact with hydrogen gas without getting wet. Moreover, since the surface which contacts the separator 15 of the negative electrode 14 has hydrophilicity, the state almost always wetted with electrolyte solution is maintained. Thereby, hydrogen gas is prevented from passing through the negative electrode 14, and the ionic conductivity of the negative electrode 14 is ensured.

  The dimension of the exterior body 10 is demonstrated. The outer diameter of the outer package 10 may be in the range of 13.5 mm to 14.5 mm. Moreover, the length of the exterior body 10 may be in the range of 49.0 mm to 50.5 mm. Further, the outer diameter of the outer package 10 may be in the range of 10.5 mm to 9.5 mm. Moreover, the length of the exterior body 10 may be in the range of 42.5 mm to 44.5 mm. When the dimensions of the outer package 10 are within the above range, dimensional compatibility with commercially available AA batteries or AAA batteries can be realized.

  According to the battery C2 according to the second embodiment configured as described above, the following effects are obtained in addition to the effects obtained by the battery C1 according to the first embodiment described above.

  As shown in FIGS. 2A and 2B, the outer package 10 of the battery C2 has a tubular structure. For this reason, it becomes easy to ensure the outstanding pressure | voltage resistance and to raise an energy density. Furthermore, it becomes easy to configure a battery module having a large charge / discharge capacity by connecting a large number of batteries C2 in parallel and in series. In particular, in the battery C2 of this embodiment, the oxygen storage chamber 19 is formed in a radial space. Furthermore, a hydrogen storage chamber 18 is formed inside the negative electrode 14. For this reason, the additional member for forming the hydrogen store room 18 and the oxygen store room 19 is unnecessary. Accordingly, since the battery C2 has a simple structure, it can be formed using only the minimum necessary members. Therefore, since the battery C2 has a small size, it has high pressure resistance and energy density. Nevertheless, since the number of parts is small, the assembly work of the battery C2 is easy.

(First Modification of Second Embodiment)
The battery C2 ′ according to the modification of the second embodiment has substantially the same structure as the battery C2 of the second embodiment. The differences are as follows. That is, the electrolytic solution 13 in which oxygen is dissolved is stored in the oxygen storage chamber 19 of the battery C2. On the other hand, the oxygen storage chamber 19 of the battery C2 ′ holds oxygen gas and the electrolytic solution 13. That is, the oxygen storage chamber 19 partially holds the electrolytic solution 13. Moreover, each electrode does not need to have flexibility.

  Furthermore, the surface of the positive electrode 16 in contact with the oxygen storage chamber 19 contains a large amount of hydrophobic material. Thereby, the manganese dioxide of the positive electrode 16 can contact oxygen gas without getting wet. Since the surface of the positive electrode 16 that contacts the separator 15 has hydrophilicity, it is almost always wet with the electrolyte. This prevents oxygen gas from passing through the positive electrode 16 and ensures ionic conductivity of the positive electrode 16. The surfaces of the electrodes 14 and 16 on the gas storage chambers 18 and 19 side may be coated or sprayed with hydrophobic carbon or Teflon. Further, the surface of the electrodes 14 and 16 on the separator 15 side may be coated or sprayed with modified nylon.

(Second Modification of Second Embodiment)
Next, a battery C3 according to a second modification of the second embodiment of the fuel cell will be described. FIG. 3 is a partially cutaway view showing the connection structure of the battery C3. The battery C3 is obtained by changing a part of the external structure of the battery C2 according to the second embodiment. Hereinafter, the changes will be mainly described. This battery C3 has a negative electrode terminal 11 electrically connected to the negative electrode 14 at one end in the axial direction (the axial direction of the outer package 10). Further, the battery C <b> 3 has a positive electrode terminal that is the outer package 10 electrically connected to the positive electrode 16 at the other end in the axial direction. As shown in FIG. 3, a protrusion 11 d is provided at the center of the negative electrode terminal 11. Further, a bottom recess 10 d is provided in the center of the bottom 10 b of the exterior body 10. The protrusion 11d and the bottom recess 10d have a shape that can be fitted. Thereby, the two batteries C3 can be connected in series.
According to this configuration, a plurality of batteries C3 can be connected in series without requiring wiring. In the example shown in FIG. 3, a convex portion is provided in the outer peripheral axis direction of the protruding portion. On the other hand, a groove is provided on the inner peripheral surface of the bottom recess. And the convex part of a projection part is comprised so that it may fit in the groove | channel of a bottom part recessed part. However, the shape of the fitting portion may be another method.

  You may form a screw part in the positive electrode terminal (exterior body 10) and the negative electrode terminal 11. FIG. That is, the protrusion 11d of the negative electrode terminal 11 may be a male screw, and the recess 10d provided on the bottom 10b of the exterior body 10 may be a female screw. Thereby, two batteries C2 can be connected more reliably.

  In the battery C3, the oxygen storage chamber (not shown) may be filled with an electrolytic solution in which oxygen is dissolved. Or you may be satisfy | filled with electrolyte solution and oxygen gas.

  4A and 4B are diagrams showing the structure of a battery module B3 in which a plurality of batteries C3 are connected. The battery module B3 has a pair of conductive current collecting plates 25 provided to face each other. The plurality of batteries C <b> 3 are disposed between the current collector plates 25. One current collector plate 25 is in contact with the outer package 10 that is a positive electrode terminal. The negative electrode terminal 11 is in contact with the other current collector plate 25. The batteries C3 are arranged in parallel with each other so as to maintain such a state. In the battery module B3, a battery group including a plurality of batteries C3 connected in parallel is connected in series (FIG. 4A).

  With such a configuration, wiring for connecting the battery C3 can be omitted. For this reason, assembly of battery module B3 becomes easy. Moreover, as shown in the enlarged view of the main part surrounded by the circle in FIG. 4A, the current collector plate 25 may be provided with a through hole 25a. In this case, the protrusion 11d of the battery C3 fits into the bottom recess 10d of the other battery C3 through the through hole 25a. Thereby, assembly of battery module B3 becomes still easier. With such a structure, the plurality of batteries C <b> 3 are supported by the current collector 25. Therefore, the battery module B3 has a self-supporting structure as an assembled battery. The battery included in the battery module B3 is not limited to the battery C3, and may be a battery C2.

  In order to send the cooling air in the parallel direction of the current collector plate 25, a blower fan 27 may be provided. The heat generated in the battery C3 is transmitted to the current collector plate 25. The current collecting plate 25 acts as a heat radiating fin, whereby the battery C3 is indirectly cooled. The current collector plate 25 serves as both a conductive member and a heat radiating member. For this reason, the material of the current collector plate 25 may have high thermal conductivity and electrical conductivity. In this respect, aluminum has a relatively low electrical resistance and a relatively high thermal conductivity. For this reason, aluminum has preferable characteristics as a material for forming the current collector plate 25. However, since aluminum easily oxidizes, the contact resistance of the current collector plate 25 tends to increase. For this reason, the aluminum plate included in the current collector plate 25 may be subjected to nickel plating. Thereby, reduction of contact resistance is achieved. The current collecting plate 25 is provided with a plurality of refrigerant passages 26 for allowing the insulating oil for cooling to pass therethrough (see FIG. 4B). Further, the arrangement of the battery C3 (through hole 25a) may be a staggered arrangement (see FIG. 4B). Thereby, the cooling air from the blower fan 27 is blown directly on the side surface of the battery C3. As a result, the cooling effect is enhanced. However, when the battery module is cold, the air heated by a heater (not shown) may be blown by the blower fan 27. Thereby, it becomes possible to warm up the battery module.

(Third Modification of Second Embodiment)
Next, a battery C4 according to a third modification of the second embodiment of the fuel cell will be described. 5A to 5C are cross-sectional views showing the structure of battery C4 (batteries C4a, C4b, and C4c). The battery C4 is obtained by changing a part of the structure of the battery C2 according to the second embodiment of the present fuel cell. Hereinafter, the changes will be mainly described. The battery C <b> 4 is provided with a hydrogen circulation port 28 that communicates with the hydrogen storage chamber 18 at the center of the negative electrode terminal 11. An oxygen circulation port 30 communicating with the oxygen storage chamber 19 is provided at the center of the bottom 10 b of the outer package 10 that acts as a positive electrode terminal. Hydrogen or oxygen stored in the storage chambers 18 and 19 of the battery C4 can be discharged through the circulation ports 28 or 30 provided in the connection portions 29 and 31.

  Further, a hydrogen gas source and an oxygen gas source are installed outside. From these, hydrogen gas and oxygen gas can be supplied to the storage chambers 18 and 19 through the flow ports 28 and 30. Connection portions 29 and 31 provide connection means for realizing connection between battery C4 and an external hydrogen gas source and oxygen gas source. Further, the shape of the connection portions 29 and 31 in the battery C4 may be the configuration shown in any of FIGS. That is, in the example (battery C4a) shown in FIG. 5A, the connection portion 29a has a protruding shape, while the connection portion 31a has a hole shape. Further, in the example shown in FIG. 5C (battery C4c), the connection portions 29c and 31c both have a protruding shape. Furthermore, in the example shown in FIG. 5B (battery C4b), both of the connection portions 29b and 31b have the shape of a through-hole. Which shape is used can be appropriately selected.

  FIG. 6 is a diagram showing a configuration of the battery bank S4. A plurality of batteries C4c are connected to the battery bank S4. The battery C4a or the battery C4b may be used depending on the shape of the connection portion. The battery bank S4 includes a hydrogen gas first header 35 and an oxygen gas first header 36. These include conductive materials. Each of them is provided with a plurality of connecting portions 35a and 36a. Thereby, the connection part 29 and the connection part 31 of the battery C4 are airtightly connected. Thereby, the hydrogen storage chamber 18 and the oxygen storage chamber 19 of the battery C4 can communicate with the hydrogen gas first header 35 and the oxygen gas first header 36, respectively. For example, 30 batteries C4 are disposed between the hydrogen gas first header 35 and the oxygen gas first header 36 and connected to the headers 35 and 36.

  When using 30 or more batteries C4, the hydrogen gas first header 35 and the oxygen gas first header 36 may be added. When a plurality of hydrogen gas first gas headers 35 and oxygen gas first headers 36 are used, the hydrogen gas first gas header 35 and the oxygen gas first header 36 are respectively connected via insulating connecting members 32 and 33 including an insulating material. The hydrogen gas second header 38 and the oxygen gas second header 39 are connected. The adjacent oxygen gas first header 36 and the hydrogen gas first header 35 are electrically connected via a conductive connecting member 34 containing a conductive material. The hydrogen gas second header 38 and the oxygen gas second header 39 are finally connected to a hydrogen gas tank and an oxygen gas tank (both are TANK in the figure). In such a configuration, the hydrogen gas and oxygen gas generated in the battery C4 are collected in the respective tanks and can be used in the battery C4. Further, hydrogen gas and oxygen gas can be supplied from these tanks to the hydrogen storage chamber 18 and the oxygen storage chamber 19 of the battery C4. Thereby, it becomes possible to generate electric power using chemical energy of hydrogen gas and oxygen gas. On the other hand, the negative electrode terminal 11 of the battery C4 and the outer package 10 serving as the positive electrode terminal are connected to the hydrogen gas first header 35 and the oxygen gas first header 36, respectively. Thereby, the electricity of the battery C4 is collected by the first headers 35 and 36. When the plurality of first headers 35 and 36 are employed, these conductive connection members 34 are connected in series, and electricity is output from the battery bank S4.

  In the battery C4, an oxygen electrolyte source in which oxygen is dissolved may be connected instead of the oxygen gas source. In this case, in the battery bank, oxygen acts as a working fluid in a state dissolved in the electrolytic solution.

(Third embodiment)
FIG. 7A is a cross-sectional view showing a structure of a unit cell (hereinafter referred to as a battery C5) constituting the fuel cell battery according to the third embodiment shown in FIG. 7B. The battery C5 employs substantially the same material and configuration as the battery C1 of the first embodiment described in FIGS. 1A and 1B. However, the battery C5 and the battery C1 are partially different in structure. The difference will be mainly described.

  This battery C5 uses the chemical energy of hydrogen and oxygen by converting it into electrical energy. Further, the battery C5 is configured as a reversible fuel cell in which a reaction mechanism of a secondary battery is incorporated in the fuel cell. The battery C5 includes a negative electrode 54, a positive electrode 56, a negative electrode case 51, and a positive electrode case 52 as main components. The negative electrode 54 and the positive electrode 56 are opposed to each other with the separator 55 interposed therebetween. The negative electrode case 51 has a hydrogen storage chamber 58. The positive electrode case 52 has an oxygen storage chamber 59.

  The main active material of the negative electrode 54 is a hydrogen storage alloy. The main active material of the positive electrode 56 is manganese dioxide. Between the negative electrode 54 and the positive electrode 56, the electrolytic solution 53 is interposed together with the separator 55. As the electrolytic solution 53, a KOH aqueous solution, which is an alkaline aqueous solution generally used in secondary batteries, is used.

  The negative electrode 54 is manufactured as follows. That is, a paste is formed by adding a solvent to the negative electrode active material, the conductive filler, and the resin. This paste is applied onto a substrate, formed into a plate shape, and cured. Similarly, the positive electrode 56 is manufactured as follows. That is, a paste is formed by adding a solvent to the positive electrode active material, the conductive filler, and the resin. This paste is applied onto a substrate, formed into a plate shape, and cured.

  The conductive filler material is carbon fiber, carbon fiber nickel-plated, carbon particles, carbon particles nickel-plated, organic fibers nickel-plated, fibrous nickel, nickel particles And nickel foil. These can be used alone or in combination. The resin is used as a binder. As this resin, a thermoplastic resin having a softening temperature up to 120 ° C., a resin having a curing temperature from room temperature to 120 ° C., a resin having an evaporation temperature of 120 ° C. or lower and soluble in a solvent, a solvent soluble in water A resin that dissolves, a resin that dissolves in a solvent soluble in alcohol, and the like can be used. As the substrate, an electrically conductive metal plate such as a nickel plate can be used. Further, a foamed nickel sheet may be used instead of the substrate.

  The surface of the negative electrode 54 that is in contact with the hydrogen storage chamber 58 contains a large amount of hydrophobic material. Thereby, the hydrogen storage alloy of the negative electrode 54 can contact with hydrogen gas without getting wet. The surface of the negative electrode 54 that contacts the separator 55 has hydrophilicity. As a result, this surface prevents hydrogen gas from passing through the negative electrode 54. This surface is almost always wet with the electrolyte. Thereby, the ionic conductivity of the negative electrode 54 is ensured. The surface of the positive electrode 56 in contact with the oxygen storage chamber 59 contains a lot of hydrophobic material. Thereby, the manganese dioxide of the positive electrode 56 can contact with oxygen gas without getting wet. The surface that contacts the separator 55 of the positive electrode 56 has hydrophilicity. Thus, this surface prevents oxygen gas from passing through the positive electrode 56. This surface is almost always wet with the electrolyte. Thereby, the ionic conductivity of the positive electrode 56 is ensured.

  The surfaces of the electrodes 54 and 56 facing the gas storage chambers 58 and 59 may be coated or sprayed with hydrophobic carbon, Teflon, or the like. The surface of the electrodes 54 and 56 on the separator 55 side may be coated or sprayed with modified nylon. Further, when manufacturing an electrode, vinyl acetate having both hydrophilic and hydrophobic characteristics may be granulated and used as a binder. Further, a mixture of a granulated binder containing vinyl acetate and a hydrophilic material may be applied to the separator 55 side of the electrodes 54 and 56. A mixture of granulated binder containing vinyl acetate and a hydrophobic material may be applied to the gas storage chambers 58 and 59 side of the electrodes 54 and 56.

The separator 55 has a structure that allows protons (H ⁺ ) to pass therethrough but hardly allows hydrogen gas and oxygen gas to pass therethrough. Specifically, the material forming the separator 55 can be a microporous membrane. The material of the microporous membrane includes polyolefin fibers such as polyethylene fibers and polypropylene fibers, polyphenylene sulfide fibers, polyfluoroethylene fibers, polyamide fibers, and the like. The separator 55 holds the electrolytic solution 53. Furthermore, in this embodiment, both surfaces of the separator 55 are wet with the electrolyte solution 53. Thereby, the separator 55 functions as a water seal separator and has high gas impermeability. Further, it is reliably prevented that hydrogen gas and oxygen gas pass through the separator 55 and contact and react with each other.

  The negative electrode 54 and the positive electrode 56 are sandwiched between the separators 55. The surface of the negative electrode 54 that is not in contact with the separator 55 is airtightly covered with the box-shaped negative electrode case 51. For this reason, the inner space formed by the negative electrode 54 and the negative electrode case 51 functions as the hydrogen storage chamber 58. The hydrogen storage chamber 58 stores the hydrogen gas generated in the negative electrode 54 without interposing additional members such as a booster and a communication path between the hydrogen gas and the negative electrode 54. Similarly, the surface of the positive electrode 56 that is not in contact with the separator 55 is airtightly covered with a box-shaped positive electrode case 52. An inner space formed by the positive electrode 56 and the positive electrode case 52 functions as an oxygen storage chamber 59. The hydrogen storage chamber 58 and the oxygen storage chamber 59 are configured independently, that is, the hydrogen storage chamber 58 and the oxygen storage chamber 59 are not communicated with each other. The oxygen storage chamber 59 is filled with the same type of electrolyte solution as the electrolyte solution 53 held in the separator 55, about 1/3 of the volume of the oxygen storage chamber 59. However, the oxygen storage chamber 59 may be filled with an electrolytic solution. In this case, oxygen may be dissolved in the electrolytic solution. However, in this case, the electrodes 54 and 56 have flexibility, and the deformation of the hydrogen storage chamber 58 extends to the oxygen storage chamber 59. As a result, when the pressure of the hydrogen storage chamber 58 is increased by the hydrogen gas, the pressure of the electrolyte becomes high so that the pressure of the electrolytic solution is substantially uniform with the pressure of the hydrogen storage chamber 58.

  The negative electrode case 51 and the positive electrode case 52 may be made of a material having high thermal conductivity and electrical conductivity. These may be made of a steel material such as aluminum. However, steel materials are easily oxidized and contact resistance is likely to increase. For this reason, the aluminum contained in the negative electrode case 51 and the positive electrode case 52 may be nickel-plated. Thereby, reduction of contact resistance is achieved. The negative electrode case 51 and the positive electrode case 52 function as a negative electrode terminal and a positive electrode terminal of the battery C5, respectively.

  The amount of the electrolyte 53 filled in the oxygen storage chamber 59 is roughly divided into two types. One is 90% or more of the volume of the oxygen storage chamber 59. The other is in the range of 20 to 40% of the volume of the storage chamber 59. In the former case, the oxygen gas generated by electrolysis is dissolved and stored in the electrolytic solution. In the latter case, oxygen is stored in the oxygen storage chamber 59 in a gas state.

  The operation of the battery C5 configured as described above will be described below. The battery C5 is charged with current as a secondary battery until it is fully charged. When the current continues to be supplied after the battery C5 reaches the fully charged state, hydrogen gas is generated from the negative electrode 54 and oxygen gas is generated from the positive electrode 56, respectively. These hydrogen gas and oxygen gas are stored in the hydrogen storage chamber 58 and the oxygen storage chamber 59, respectively, without contacting each other.

  When the discharge of the battery C5 is started, a normal discharge reaction as a secondary battery occurs between the negative electrode 54 and the positive electrode 56. Thereby, a current flows through the load. At this time, the amount of electricity of the negative electrode 54 and the positive electrode 56 decreases due to the discharge. The reduced amount of electricity of the negative electrode 54 and the positive electrode 56 is compensated by charging with hydrogen gas and oxygen gas stored in the hydrogen storage chamber 58 and the oxygen storage chamber 59. When the oxygen storage chamber 59 is filled with an electrolytic solution in which oxygen is dissolved, the positive electrode 56 is charged with oxygen in the electrolytic solution.

In the negative electrode 54, protons released from the charged hydrogen storage alloy (MH) are supplemented by hydrogen gas. Thereby, the charged state of the negative electrode is maintained. On the other hand, in the positive electrode 56, manganese oxyhydroxide (MnOOH) generated by reducing charged manganese dioxide (MnO ₂ ) is oxidized again by oxygen. Thereby, the charge state of a positive electrode is maintained. After the hydrogen gas and oxygen gas in the storage chambers 58 and 59 are consumed, the battery C5 is discharged in the same manner as a normal secondary battery.

  That is, the battery C5 according to the present embodiment can store electric energy in the electrode as a secondary battery by charging with electricity. Further, the battery C5 stores the electric energy supplied at the time of overcharging as gas (chemical energy) in the storage chambers 58 and 59. The battery C5 can use the stored chemical energy by reconverting it into electrical energy. Furthermore, by increasing the pressure resistance and sealing performance of the storage chambers 58 and 59 and the battery C5 including the storage chambers 58 and 59, it is possible to increase the gas storage amount per volume. As a result, the energy density of the battery C5 can be significantly improved (for example, about several tens of times) as compared with the conventional secondary battery. Moreover, the hydrogen gas generated at the negative electrode 54 or the oxygen gas generated at the positive electrode 56 is directly stored in the storage chambers 58 and 59 during overcharge. For this reason, there is no need to provide an additional gas booster or communication passage. Therefore, since the battery C5 has a simple structure, it can be manufactured and supplied at low cost.

  When the battery C5 is discharged, electric energy is output by the electrode reaction of the secondary battery. For this reason, the followability with respect to the load is greatly improved as compared with the conventional fuel cell. As a result, the battery C5 can be used for an application with a large load fluctuation that requires instantaneous high output, such as a vehicle. At this time, the battery C5 can be used alone without requiring an additional secondary battery or a power storage device such as a capacitor.

  Moreover, in the battery C5 according to this embodiment, the positive electrode 56 includes manganese dioxide as a positive electrode active material. For this reason, the positive electrode 56 has excellent durability and high life characteristics.

  In the battery C5 shown in FIG. 7A, the outer peripheral surface 55a of the separator 55 is covered with an insulating portion 67 having the same thickness as the separator 55. The outer dimensions of the negative electrode case 51, the positive electrode case 52, and the insulating portion 67 are adjusted so that the outer peripheral surface 51a of the negative electrode case 51, the outer peripheral surface 52a of the positive electrode case 52, and the outer peripheral surface 67a of the insulating portion 67 are flush with each other. . The insulating part 67 is made of an airtight material. Further, the separator 55 prevents the passage of gas by the action of the electrolytic solution. For this reason, even if oxygen gas or hydrogen gas reaches the outer peripheral surface 55a of the separator 55, they do not leak to the outside of the battery C5.

  Steps 65 or 66 are provided in the openings of the negative electrode case 51 and the positive electrode case 52, respectively. The widths of the steps 65 and 66 are substantially equal to the thickness of the negative electrode 54 and the positive electrode 56. The negative electrode 54 and the positive electrode 56 are attached so as to cover the openings of the negative electrode case 51 and the positive electrode case 52, respectively.

FIG. 7B is an assembled cross-sectional view showing the structure of a fuel cell B5 including a plurality of the batteries C5 shown in FIG. 7A. The fuel cell B5 includes a positive electrode terminal 64, a negative electrode terminal 63, an insulating casing 62 that encloses the battery C5, lid members 68 and 69, and mounting bolts 70 as main components. The lid members 68 and 69 are members for fastening and fixing the battery C5 in the axial direction of the insulating casing 62. These main components are covered with a metal protective casing 61.

In the fuel cell B <b> 5, a plurality of cells C <b> 5 are included in the insulating casing 62 along the axial direction of the insulating casing 62. Outer peripheral surfaces 51a and 52a of battery C5 are along inner peripheral surface 62a of insulating casing 62 containing an insulating material. The side surface 51b of the negative electrode case 51 and the side surface 52b of the positive electrode case 52 of the adjacent battery C5 are in contact with each other. A negative electrode terminal 63 and a positive electrode terminal 64 of the fuel cell B5 are provided at both ends of the plurality of batteries C5. A lid member 68 or 69 is fitted to the inner peripheral surface 61 a of the protective casing 61 on the outer side of each of the negative electrode terminal 63 and the positive electrode terminal 64. Screw holes are formed in the lid members 68 and 69. The protective casing 61 has a bolt hole 70a. The protective casing 61 and the lid members 68 and 69 are fixed by the mounting bolts 70, respectively. Thus, the battery C5 and the positive and negative terminals 63 and 64 are housed in the protective casing 61.

8A and 8B show a configuration example of a battery module including a plurality of fuel cells B5 connected to each other.
In the battery module S5, one end of a metal wire 474 is attached to the fuel cell B5 , and the other end is attached to the steel tower 478. Thereby, the plurality of fuel cells B5 can be suspended from the steel tower 478. The negative electrode terminal 63 and the positive electrode terminal 64 of the adjacent fuel cell B5 are connected by a bus bar 477 through a circuit breaker 476 that can be opened and closed.

The battery module S5 as described above may be applied to a power system. When battery module S5 is applied to an electric power system, a voltage becomes a high voltage and a withstand voltage structure is adopted. For this reason, in this case, the circuit breaker 476 is also suspended by the insulated wire 474 in order to ensure the ground pressure resistance performance.

(Fourth embodiment)
9A and 9B are cross-sectional views showing the structure of a reversible fuel cell C10 (hereinafter simply referred to as cell C10) according to the fourth embodiment of the present fuel cell. FIG. 9A is a partial cutaway view in the longitudinal direction. 9B is a cross-sectional view taken along line AA in FIG. 9A. The battery C10 has a structure covered with an outer shell 100. Inside the outer shell 100, a plurality of positive electrodes 110 formed in a tube shape are accommodated along the axial direction of the outer shell 100 (the X direction in FIG. 9A). A negative electrode 120 is filled and disposed around the positive electrode 110 with a separator 130 interposed therebetween. In addition, the negative electrode, the positive electrode, the separator, and the electrolytic solution, which are the basic elements of the battery C10 according to the present embodiment, are the same substances / cells as those of the battery C1 according to the first embodiment described above, unless otherwise described below. It may be a composition and structure.

  The outer shell 100 has a cylindrical body portion 101 and a bulging portion 102. The bulging part 102 is arranged at both end openings of the body part 101. The bulging portion 102 bulges outward from the opening in a direction away from the opening, and covers the opening. A packing 103 for keeping the inside of the outer shell 100 liquid-tight is disposed between the trunk portion 101 and the bulging portion 102. The body portion 101 and the bulging portion 102 may be made of steel, and preferably high tensile steel. Thus, while the trunk | drum 101 has a cylindrical shape, the bulging part 102 bulges outward. As a result, the outer shell 100 has a structure that can withstand even the inside of the outer shell 100 having an ultrahigh pressure.

  Oxygen storage chambers 136 a and 136 b are provided in the inner space of the bulging portion 102 inside the outer shell 100. The left and right oxygen storage chambers 136a and b are divided by a partition plate 135, respectively. The oxygen storage chambers 136a and 136b can be connected to external equipment via flanges 211 and 212 attached to the outer shell 100. A positive electrode 110, a negative electrode 120, a separator 130, and a current collector 134 are disposed in a space between the left and right oxygen storage chambers 136 a and 136 b and surrounded by the partition plate 135 and the body portion 101.

  FIG. 10 is a partially cutaway view for explaining the structure of the electrode in battery C10. The current collector 134 is a perforated steel pipe plated with nickel. The positive electrode 110 is formed by applying a paste-like mixture containing manganese dioxide around the current collector 134. The positive electrode 110 may be applied directly to the current collector 134 with the composite material. Alternatively, the positive electrode 110 may be formed by spreading a positive electrode sheet formed by applying a composite material on nickel foam to the current collector 134. A separator 130 is interposed between the positive electrode 110 and the negative electrode 120 containing the oxygen storage alloy. The separator 130 prevents the positive electrode 110 and the negative electrode 120 from contacting each other. The oxygen storage chambers 136 a and 136 b located on the left and right sides of the outer shell 100 are in communication with each other via the current collector 134. The electrolyte solution 137 in the oxygen storage chambers 136a and 136b can flow in the direction indicated by the arrow in FIG.

Between the left and right partition plates 135, the outer space of the separator 130 is filled with a hydrogen storage alloy having an average particle diameter of 20 μm. In this configuration, the porosity is approximately 35%. The size of the porosity varies depending on how the hydrogen storage alloy is filled. The porosity may be greater than 35%. When the average particle diameter is 5 to 50 μm, the porosity is about 30 to 60%. Such a void functions as a hydrogen storage chamber 138. In addition, said average particle diameter is JIS like other embodiment.
This is a value expressed by using a sphere equivalent diameter by the light scattering method of Z8910.

  As shown by a broken line in FIG. 9A, a hydrogen gas storage source 121 and a storage passage 122 are connected to the hydrogen storage chamber 138 of the battery C10. The negative electrode 120 can be charged with hydrogen gas supplied from the outside.

  The positive electrode current collector 134 passes through a nickel-plated steel partition plate 135. Both ends of the current collector 134 are supported by a partition plate 135. For this reason, the bulging part 102 and the positive electrode 110 are electrically connected via the partition plate 135. Thereby, the bulging part 102 functions as a positive electrode terminal of the battery C10. Further, the body portion 101 that is in direct contact with the negative electrode 120 functions as a negative electrode terminal. The packing 103 has an insulating property as well as a sealing property. Thereby, the packing 103 prevents the positive electrode 110 and the negative electrode 120 from being short-circuited.

The operation of the battery C10 configured as described above will be described below. The electrolyte C 137 in which oxygen is dissolved is supplied to the battery C10 from one flange 211 (right side in FIG. 9A). This electrolytic solution 137 is an electrolytic solution in which oxygen is dissolved at a high concentration, and can be referred to as a high concentration oxygen-dissolved electrolytic solution. The electrolytic solution 137 in which oxygen is dissolved at a high concentration flows through the pipe-shaped current collector 134, passes through punch holes provided in the current collector 134, and contacts the positive electrode 110. Thereby, the manganese oxyhydroxide in the positive electrode is oxidized by the oxygen dissolved in the electrolytic solution to become manganese dioxide. As a result, the positive electrode is charged. As a result, oxygen dissolved in the electrolytic solution is consumed to generate H ₂ O, and the oxygen concentration in the electrolytic solution is lowered. The electrolyte solution 137 (low-concentration oxygen-dissolved electrolyte solution) having a reduced oxygen concentration is discharged into the oxygen storage chamber 136b on the left, and is finally discharged out of the system from the flange 212. On the other hand, the negative electrode 120 is charged with hydrogen gas supplied from an external hydrogen gas storage source 121.

  When an electrical load is connected between the bulging portion 102 functioning as a positive electrode terminal and the body portion 101 functioning as a negative electrode terminal using a wiring cable (not shown), the battery C10 is discharged. Thereby, a current is supplied to the electric load. The load current can be taken out from the bulging portions 102 at both ends. For this reason, the current flowing through the current collector 134 is divided into left and right parts, and the Joule heat loss is about 1/4.

Next, a case where electric energy is converted into chemical energy and the battery C10 is charged will be described. The battery C10 can store hydrogen gas generated by overcharging in the hydrogen storage chamber 138. The battery C10 can store oxygen gas in the oxygen storage chambers 136a and 136b in a state in which the oxygen gas is dissolved in the electrolyte. That is, the battery C10 of the present embodiment can store electric energy converted into chemical energy. Further, the battery C10 can appropriately convert chemical energy into electric energy and output it. For this reason, unlike the conventional secondary battery, the battery C10 is not limited in the storage capacity by the amount of the active material.

  Similarly to the battery C1 according to the first embodiment, the battery C10 according to the present embodiment is also discharged by a battery reaction and charged with hydrogen gas and oxygen during discharge. During such charge and discharge, manganese dioxide functions as a catalyst for the reaction at the positive electrode. On the other hand, the hydrogen storage alloy functions as a catalyst for the reaction in the negative electrode.

  A power generation process using the battery C10 according to the fourth embodiment is shown in FIG. A pipe 220 is connected to the battery C10 through a flange 212. The electrolyte solution 137 deteriorated by the discharge of the battery C10 is carried to the first chamber 231 of the salt concentration adjusting device 230 via the pipe 220. A reverse osmosis membrane 233 is attached to the salt concentration adjusting device 230. The salt concentration adjusting device 230 is divided into a first chamber 231 and a second chamber 232 by the reverse osmosis membrane 233. The reverse osmosis membrane 233 has a function of selectively permeating moisture in the electrolytic solution 137. The permeated moisture is stored as drainage in the second chamber 232 and is discharged out of the system through the drain port 234. The electrolyte solution 137 of the salt concentration adjusting device 230 is conveyed to the oxygen concentration adjusting device 250 via the pipe 221. An oxygen storage source 251 and a storage passage 252 are connected to the bottom of the oxygen concentration adjusting device 250. When the oxygen gas and the electrolytic solution 137 come into contact with each other, the dissolved oxygen concentration in the electrolytic solution is increased. Note that a separate storage passage 253 may be provided in the oxygen concentration adjusting device 250 so that oxygen generated by overcharging can be stored in the oxygen storage source 251. Thereby, the high concentration oxygen-dissolved electrolyte stored in the oxygen storage source 251 can be returned to the oxygen concentration adjusting device 250. This electrolytic solution can be used to adjust the oxygen concentration lowered by the discharge.

  The temperature of the electrolyte solution 137 discharged from the oxygen concentration adjusting device 250 is increased by using the battery. The electrolytic solution 137 is cooled by the cooler 260 and reaches a predetermined temperature. Thereafter, the electrolyte solution 137 is pressurized by the pump 270 and returned to the battery C10 through the pipe 222.

(Fifth embodiment)
FIG. 12 is a schematic cross-sectional view in the axial direction of a reversible fuel cell (hereinafter simply referred to as a cell C30) according to the fifth embodiment of the present fuel cell. In addition, the negative electrode, the positive electrode, the separator, and the electrolytic solution, which are the basic elements of the battery C30 according to the present embodiment, are the same substances / It may have a composition and structure. As shown in FIG. 12, the battery C30 includes an exterior body 300, a current collector 310, and an electrode housed in the exterior body as main components. The exterior body 300 includes a circular tube 301 and a disk-shaped lid member 302. The lid member 302 is provided at the openings at both ends of the circular tube 301. The material of the circular tube 301 and the lid member 302 is obtained by applying nickel plating to iron.

  The material of the current collector 310 is made of a conductive material obtained by nickel-plating rod-shaped iron. Both end portions of the current collector 310 pass through a hole provided in the center of the lid member 302. Nuts 311 are screwed into both ends of the current collector 310. The current collector 310 is fixed to the lid member 302 by the nut 311. The nut 311 has a bag shape. Thereby, it is prevented that the electrolyte solution inside a battery leaks outside. An insulating packing 312 is provided between the nut 311 and the lid member 302. Thereby, it is prevented that the electrical power collector 310 and the cover member 302 electrically contact. A packing 303 for sealing the inside of the battery is provided between the circular tube 301 and the lid member 302. The packing 303 has an insulating property. For this reason, the circular tube 301 and the lid member 302 are prevented from being in electrical contact. The current collector 310 is prevented from being corroded by the electrolytic solution by being nickel-plated.

  The positive electrode 320 and the negative electrode 330 are stacked in the axial direction of the circular tube 301 (X direction in FIG. 12) via the separator 340. The positive electrode 320 and the negative electrode 330 are housed in the exterior body 300. The separator holds the electrolytic solution. The separator 340 can insulate between positive and negative electrodes and transmit ions. The positive electrode 320 contains manganese dioxide filled with foamed nickel. The negative electrode 330 includes a hydrogen storage alloy filled with foamed nickel. Thereby, hydrogen gas can permeate | transmit a negative electrode. The positive electrode 320 has a substantially disk shape having an outer shape slightly larger than the inner diameter of the circular tube 301. A part of the positive electrode 320 on the circumference 180 degrees away from each other is cut off. The outer periphery of the positive electrode 320 is in contact with the inner surface of the circular tube 301 (see FIG. 13A) except for the cut-out portion. A notch 321 is formed between the cut portion of the positive electrode 320 and the circular tube 301. Between the positive electrode 320 and the current collector 310 inside the positive electrode 320, a polypropylene PP packing 351 having the same thickness as the positive electrode 320 is interposed. The PP packing 351 insulates the positive electrode 320 and the current collector 310 from each other.

13A shows a BB cross section of the battery C30, and FIG. 13B shows a CC cross section of the battery C30.
The negative electrode 330 has a disk shape. The negative electrode 330 has a U-shaped cross section that opens inward in the inner circumferential direction. A current collector 310 passes through a hole provided in the center of the negative electrode 330. The diameter of the through hole is slightly smaller than the outer diameter of the current collector 310. For this reason, the inner diameter portion of the negative electrode 330 and the outer diameter portion of the current collector 310 are in contact with each other. A space surrounded by the negative electrode 330 and the current collector 310 forms a hydrogen storage chamber 380. A separator 340 is interposed between the positive electrode 320 and the negative electrode 330. The outer peripheral surface of the negative electrode 330 in the radial direction is covered with PP packing 352. The outer diameter of the PP packing 351 is smaller than the inner diameter of the circular tube 301. For this reason, a space (gap) 331 is formed between the PP packing 351 and the circular tube 301 (see FIG. 13B). Further, the portion of the negative electrode 330 not facing the separator 340 and the hydrogen storage chamber 380 is covered with PP packing 353.

  The lid member 302 is provided with a hydrogen gas supply port 373. The positive electrode 320 and the PP packing 353 are provided with holes 351a or 353a. These holes 351 a and 353 a form a hydrogen gas passage 370 communicating with the hydrogen storage chamber 380. As shown in FIG. 14, a high-pressure hydrogen gas storage source 371 is connected to the hydrogen gas supply port 373 via a storage passage 372. High-pressure hydrogen gas can be supplied to each hydrogen storage chamber 380 via these hydrogen gas passages 370.

  The lid member 302 is provided with an electrolyte inlet 365 and an electrolyte outlet 366 that are outlets and outlets for the electrolyte in which oxygen is dissolved, at positions 180 degrees apart. These electrolyte outlets 365 and 366 communicate with the notch 321. The notch 321 communicates with a gap 331 between the PP packing 351 and the circular tube 301. For this reason, the electrolytic solution flowing in from the electrolytic solution inlet 365 circulates in the battery C30 along the inner surface of the circular tube 301 and flows out from the electrolytic solution outlet 366. As shown in FIG. 14, an electrolyte supply source 361 in which high-concentration oxygen is dissolved is connected to an electrolyte inlet 365 via a supply passage 362. On the other hand, an electrolyte adjustment chamber 363 is connected to the electrolyte outlet 366 via a discharge passage 364. The electrolytic solution adjustment chamber 363 processes the electrolytic solution with a reduced oxygen concentration.

  FIG. 15 is a system diagram related to the battery C30 of the fifth embodiment including an electrolytic solution treatment process. The electrolytic solution exiting from the electrolytic solution outlet 366 of the battery C30 is sent to the cooler 326 via the pipe 364a. The electrolytic solution whose temperature has increased due to the use of the battery is cooled by the cooler 326 and becomes a constant temperature. Thereafter, the electrolytic solution is pressurized by the pump 327 and conveyed to the electrolytic solution adjustment chamber 363 through the pipe 364b. Here, a part of the water is selectively removed from the electrolytic solution. Further, the electrolytic solution is supplied with oxygen from the electrolytic solution supply source 361. Thereby, the oxygen concentration of electrolyte solution is adjusted. Thereafter, the electrolytic solution is returned to the battery C30 via the pipe 364c.

Next, the operation of the battery C30 will be described. As described above, the hydrogen gas supplied from the hydrogen gas supply port 373 is led to the hydrogen storage chamber 380 and charges the negative electrode 330. On the other hand, the electrolytic solution in which oxygen is dissolved at a high concentration supplied from the electrolytic solution inlet 365 is supplied from the notch 321 to the positive electrode 320 to charge the positive electrode 320. When the positive electrode 320 is charged, H ₂ O is generated. The H ₂ O is mixed with the electrolytic solution and discharged from the electrolytic solution outlet 366 to the outside of the battery C30.

  Similar to the charging / discharging in the battery C1 according to the first embodiment, the battery C30 according to the present embodiment is also discharged by the function of the secondary battery and chemically charged with hydrogen gas and oxygen during discharging. That is, the battery C30 is discharged as a secondary battery and charged with gas at the same time. At this time, manganese dioxide functions as a catalyst for the reaction in the positive electrode. On the other hand, the hydrogen storage alloy functions as a catalyst for the reaction in the negative electrode. Furthermore, the battery C30 can be charged by an electric current. Hydrogen gas generated by overcharging can be stored in the hydrogen gas storage source 371 through the hydrogen gas passage 370 and the storage passage 372. The oxygen gas can be stored in a state dissolved in the electrolyte. In other words, the battery C30 of the present embodiment can store electrical energy converted into chemical energy. For this reason, unlike the conventional secondary battery, the storage capacity of the battery C30 is not limited by the amount of the active material.

  Note that hydrogen gas is supplied to the negative electrode of the battery C30. For this reason, the negative electrode is not oxidized even by discharge. Therefore, the lifetime of the negative electrode is not degraded by volume expansion and contraction. The positive electrode is oxidized by the oxygen in the oxygen-dissolved electrolyte and is charged. For this reason, a positive electrode does not deteriorate by discharge.

<Energy efficiency of reversible fuel cells>
The relationship between the pressure and energy efficiency of the fuel cell is described below. When taking out electric power using a chemical reaction, the relationship of ΔH = ΔG + TΔS is established, where ΔH is the energy obtained from the chemical substance used, ΔG is the amount of electricity that can be taken out, and TΔS is the generated heat. ΔH is also called reaction generation heat or heat generation amount. ΔH takes a negative value during an exothermic reaction such as a combustion reaction. ΔG is called free energy. ΔG is energy that can be taken out as work, and is called exergy as effective energy.

  TΔS is the heat generated with the reaction, and is represented by the product of entropy change and temperature. ΔG / ΔH is the ability to extract effective energy and is called exergy efficiency. The power storage efficiency (that is, the discharge power amount with respect to the charge power amount) when charging and discharging the nickel metal hydride secondary battery can be increased to about 90 to 99%. On the other hand, the exergy efficiency ΔG / ΔH when electrolyzing water to produce hydrogen and oxygen is 83% at room temperature. For this reason, it is difficult for the power storage efficiency to exceed 83%.

  One of the problems to be solved by the present fuel cell is to bring the exergy efficiency ΔG / ΔH as close to 1 as possible, and reduce the rate of heat (TΔS) in ΔH, and increase the proportion of ΔH as much as possible. It is to provide a device capable of realizing conversion into electrical energy (ΔG). In order to increase the power generation efficiency η (= ΔG / ΔH), it is only necessary to decrease TΔS and increase ΔG. ΔG is a value determined by temperature and pressure. By increasing this, the value of ΔG / ΔH can be increased.

  When using a fuel cell to convert hydrogen to electrical energy, 17% of the chemical energy ΔH obtained from hydrogen becomes heat (TΔS). In order to reduce the amount of heat generated, high pressure hydrogen may be sent to the fuel cell to generate power. Thereby, generation | occurrence | production of a heat | fever can be suppressed and it becomes possible to raise electric power generation efficiency. When hydrogen is produced from electrical energy using a fuel cell, heat (TΔS) corresponding to 17% of ΔH obtained from hydrogen is used. At that time, if hydrogen and oxygen are generated at normal pressure, work is performed on the atmosphere, and loss occurs. Therefore, electrolysis is performed in a sealed space. Thereby, TΔS used can be made smaller than 17% of ΔH. FIG. 23 shows the thermodynamic calculation results. This figure shows that TΔS decreases as the pressure increases.

  In this fuel cell, oxygen gas and hydrogen gas obtained by electrolyzing an electrolyte solution are stored and used at a high pressure without returning to atmospheric pressure. Thereby, high power generation efficiency η can be realized.

  Further, the potential V and the free energy ΔG are proportional. That is, the relationship V = ΔG / FM is established (where F: Faraday coefficient, M: molecular weight). That is, the higher the potential V, the larger ΔG and the higher the power generation efficiency η. As shown in FIG. 22, the present fuel cell almost always maintains a high potential and maintains a high power generation efficiency η.

  The terminal voltage when one fuel cell is opened is in the range of 0.8 to 1.48V. When the discharge of the positive electrode proceeds, most of the composition becomes manganese oxyhydroxide, and when the pressure of the electrolytic solution is 0.1 MPa, the terminal voltage becomes 0.8V. When the charging of the positive electrode proceeds and most of the composition becomes manganese dioxide, and the pressure of the electrolyte becomes a high pressure exceeding 10 MPa, the terminal voltage becomes 1.48V.

(Sixth embodiment)
FIG. 16 is a schematic cross-sectional view in the axial direction of a cylindrical stacked reversible fuel cell according to the sixth embodiment of the present fuel cell. A cylindrical laminated fuel cell battery 71 (hereinafter simply referred to as a laminated battery) shown in FIG. 16 mainly includes an exterior body 75, a current collector 77, and an electrode body 73 housed inside the exterior body 75. As an element. The exterior body 75 includes a bottomed cylindrical can 72 and a disk-shaped lid member 76. The lid member 76 is attached to the opening 72 c of the cylindrical can 72. The cylindrical can 72 and the lid member 76 may be made of iron or other metals. The outer diameter of the lid member 76 is slightly larger than the inner diameter of the opening 72c of the cylindrical can 72. After the lid member 76 is housed in the electrode body 73, the lid member 76 is tightly fitted in the cylindrical can opening 72c.

  The electrode body 73 includes a positive electrode 73a including a positive electrode active material, a negative electrode 73b including a negative electrode active material, and a separator 73c. The separator 73c is interposed between the positive electrode 73a and the negative electrode 73b, and transmits ions but does not transmit electrons. The positive electrode 73 a, the negative electrode 73 b, and the separator 73 c are stacked in the axial direction (X direction in FIG. 16) of the cylindrical can 72 and housed in the exterior body 75. Note that an electrolytic solution (not shown) is held in the separator 73c. The positive electrode 73a, the negative electrode 73b, and the separator 73c all have a disk shape with a hole in the center. The outer diameter 73ab of the positive electrode 73a is smaller than the inner diameter 72a of the cylindrical can 72. For this reason, the positive electrode 73a and the cylindrical can 72 are not in contact. On the other hand, the outer diameter 73bb of the negative electrode 73b is larger than the inner diameter 72a of the cylindrical can 72. For this reason, the outer periphery 73bb of the negative electrode is in contact with the inner surface 72a of the cylindrical can 72. Thereby, the negative electrode 73b and the cylindrical can 72 are electrically connected. The outer diameter 73bb of the negative electrode 73b may be 100 μm larger than the inner diameter 72a of the cylindrical can 72.

  The material of the current collector 77 is a conductive material including nickel-plated iron. Nickel plating prevents the current collector 77 from being corroded by the electrolyte contained in the separator 73c. The current collector 77 has a rod-shaped shaft portion 77a and a stop portion 77b disposed at one end of the shaft portion 77a. The shaft portion 77a of the current collector 77 passes through the center of the electrode body 73 including the positive electrode 73a, the negative electrode 73b, and the separator 73c in the axial direction of the exterior body 75 (X direction in FIG. 16). The diameter of the hole 73aa provided in the center of the positive electrode 73a is smaller than the outer diameter of the shaft portion 77a. For this reason, the positive electrode 73a is in contact with the shaft portion 77a and is electrically connected to the shaft portion 77a. On the other hand, the diameter of the hole 73ba provided in the center of the negative electrode 73b is larger than the outer diameter of the shaft portion 77a. For this reason, since the negative electrode 73b is not in contact with the shaft portion 77a, it is electrically insulated from the shaft portion 77a.

  The electrode bodies 73 are arranged so as to be sequentially stacked on the stoppers 77b of the current collector. The stopper portion 77 b prevents the electrode body 73 from dropping from the end portion of the current collector 77. The shape of the stop portion 77b is a disc shape. The stopper 77b is disposed on the cylindrical can bottom 72b. An insulating plate 74 is disposed between the cylindrical can bottom 72b and the stopper 77b. As a result, the current collector 77 and the cylindrical can 72 are prevented from coming into contact and being electrically short-circuited. An end portion of the shaft portion 77 a opposite to the stop portion 77 b is supported by a bearing 78 provided at the center of the lid member 76. In order to prevent an electrical short circuit between the cover member 76 and the shaft portion 77a, the bearing 78 has an insulating property. The shaft portion 77 passing through the lid member 76 functions as a positive electrode terminal 77d. The cylindrical can 72 functions as a negative electrode terminal.

Next, the operation and effect of the sixth embodiment, particularly the cooling effect will be described.
<About cooling structure>
The negative electrode 73b is strongly pressed against the cylindrical can 72, and these are in close contact with each other. The heat generated in the negative electrode 73b is directly transmitted to the cylindrical can 72 with a small resistance. The heat generated in the positive electrode 73a is transferred to the negative electrode 73b through the separator 73c. Although the separator 73c is difficult to transmit heat, it is thin (in this embodiment, 10 μm) and is only one sheet. For this reason, the separator 73c does not greatly hinder heat conduction. As described above, the heat generated in the electrodes 73a and 73b is transmitted to the cylindrical can 72 with a small thermal gradient. Thereby, it is possible to suppress the temperature rise inside the laminated battery.

  In this way, the laminated battery can reduce the temperature rise at the center. For this reason, it is not necessary to provide a pipe or the like for flowing the refrigerant inside the battery. Furthermore, the exterior body 75 is exposed to the outside. For this reason, a laminated battery can suppress a temperature rise effectively compared with the conventional winding battery. Here, the difference in temperature rise between the laminated battery according to the present embodiment and the conventional wound battery will be described using a calculation example.

The overall heat transfer coefficient (U ₁ ) of the wound battery is expressed by Equation 1. On the other hand, the overall heat transfer coefficient (U ₂ ) of the laminated battery according to the present invention is expressed by Equation 2.

Here, calculation will be made taking an 18650 type battery as an example. The specifications of the wound battery
t = 0.5 mm, t ₊ = t ₋ = t _s = 10 μm,
k = k ₊ = k ₋ = 40 Wm ⁻² deg ⁻¹ ,
h ₀ = 100 Wm ⁻² deg ⁻¹ , h ₁ = ¹ Wm ⁻² deg ⁻¹ ,
k _s = ¹ Wm ⁻² deg ⁻¹ , n = 9 / 0.03 = 300.
Substituting these values into Equation 1 yields U ₁ = 0.0011 Wm ⁻² deg ⁻¹ .

On the other hand, the specifications of the laminated battery according to this embodiment are as follows:
h ₀ = 100 Wm ⁻² deg ⁻¹ , t = 0.5 mm, k = 40 Wm ⁻² deg ⁻¹
h ₁ = 10000 Wm ⁻² deg ⁻¹ , t ^* = 0.409 m,
k ^* = 40 Wm ⁻² deg ⁻¹ .
Substituting these values into Equation 2 yields U ₂ = 100 Wm ⁻² deg ⁻¹ .

  When both are compared, it can be said that the laminated battery having the cooling structure according to the present invention is excellent in heat transfer by nearly 100,000 times as compared with the conventional wound battery.

(Modification of the sixth embodiment)
FIG. 17 is a schematic cross-sectional view in the axial direction of a pipe-stacked reversible fuel cell (hereinafter simply referred to as a pipe cell) according to a modification of the sixth embodiment of the present fuel cell. The pipe battery 81 shown in FIG. 17 includes an exterior body 85, a current collector 87, and an electrode body 83 housed inside the exterior body 85 as main components. The exterior body 85 includes a circular tube 82 and a disk-shaped lid member 86. The lid member 86 is attached to the openings 82 b at both ends of the circular tube 82. The circular tube 82 and the lid member 86 may be made of iron or another metal. The outer diameter of the lid member 86 is slightly larger than the inner diameter of the opening 82b of the circular tube 82. After the lid member 86 is accommodated in the electrode body 83, the lid member 86 is tightly fitted in the circular tube opening 82b.

  The electrode body 83 includes a positive electrode 83a including a positive electrode active material, a negative electrode 83b including a negative electrode active material, and a separator 83c. The separator 83c is interposed between the positive electrode 83a and the negative electrode 83b. The positive electrode 83 a, the negative electrode 83 b, and the separator 83 c are stacked in the axial direction (X direction in FIG. 17) of the circular tube 82 and are housed inside the exterior body 85. Note that an electrolytic solution (not shown) is held in the separator 83c. Each of the positive electrode 83a, the negative electrode 83b, and the separator 83c has a disk shape with a hole in the center. The outer diameter 83bb of the negative electrode 83b is smaller than the inner diameter 82a of the circular tube 82. For this reason, the negative electrode 83 b is not in contact with the circular tube 82. On the other hand, the outer diameter 83ab of the positive electrode 83a is larger than the inner diameter 82a of the circular tube 82. For this reason, the positive electrode 83 a is in contact with the inner surface 82 a of the circular tube 82, and the positive electrode 83 a is electrically connected to the circular tube 82. The outer diameter 83ab of the positive electrode 83a may be 100 μm larger than the inner diameter 82a of the circular tube 82.

  The material of the current collector 87 is a conductive material including rod-shaped iron plated with nickel. The current collector 87 has a shaft portion 87a at the center portion and end portions 87b at both end portions. The shaft portion 87a of the current collector 87 passes through the center of the electrode body 83 including the positive electrode 83a, the negative electrode 83b, and the separator 83c in the axial direction of the exterior body 85 (X direction in FIG. 17). The diameter of the hole 83ba provided in the negative electrode 83b is smaller than the outer diameter of the shaft portion 87a. Therefore, the negative electrode 83b is in contact with the shaft portion 87a and is electrically connected to the shaft portion 87a. On the other hand, the diameter of the hole 83aa provided in the positive electrode 83a is larger than the outer diameter of the shaft portion 87a. For this reason, since the positive electrode 83a is not in contact with the shaft portion 87a, it is electrically insulated from the shaft portion 87a.

  The electrode bodies 83 are sequentially stacked in a skewered state on the shaft portion 87a of the current collector. Both end portions 87 b of the current collector 87 are supported by bearings 88 provided at the center of the lid member 86. The bearing 88 has an insulating property. Thereby, it is prevented that the cover member 86 and the electrical power collector 87 raise | generate an electrical short circuit. The current collector end portion 87b penetrating the lid member 86 functions as a negative electrode terminal 87d. The circular tube 82 functions as a positive electrode terminal.

(Seventh embodiment)
FIG. 18 is a schematic cross-sectional view in the axial direction of a cylindrical stacked reversible fuel cell (hereinafter referred to as a donut cell) according to a seventh embodiment of the present fuel cell. A donut battery 41 shown in FIG. 18 includes an exterior body 45, a current collector 47, and an electrode body 43 housed inside the exterior body as main components. The exterior body 45 has a bottomed cylindrical outer structure 42 and a lid member 46. The lid member 46 is attached to the opening 42 c of the outer structure 42. The outer structure 42 and the lid member 46 may include nickel-plated iron. The outer structure 42 and the lid member 46 each have a cylindrical side portion 42a or 46a and a bulging portion 42b or 46b bulging in a dome shape at the bottom. The lid member 46 is shorter than the outer structure 42. The outer diameter of the lid member 46 is smaller than the inner diameter of the opening 42 c of the outer structure 42. The lid member 46 is joined to the outer structure 42 via an insulating seal member 48. The opening of the lid member 46 and the opening of the outer structure 42 are opposed to each other. The insulating seal member 48 electrically insulates the outer structure 42 and the lid member 46. Furthermore, the insulating seal member 48 forms a sealed space inside the exterior body 45 by sealing the joint portion. The insulating seal member 48 is a substance having both insulating properties and sealing properties, and may be, for example, asphalt pitch.

  The electrode body 43 includes a positive electrode 43a including a positive electrode active material, a negative electrode 43b including a negative electrode active material, and a separator 43c. The separator 43c is interposed between the positive electrode 43a and the negative electrode 43b. The positive electrode 43 a, the negative electrode 43 b, and the separator 43 c are stacked in the axial direction of the outer structure 42 (X direction in FIG. 18) and housed in the exterior body 45. In addition, the electrolyte solution (not shown) is hold | maintained at the separator 43c. Each of the positive electrode 43a, the negative electrode 43b, and the separator 43c has a disk shape with a hole in the center. The outer diameter 43aa of the positive electrode 43a is smaller than the inner diameter 42aa of the outer structure 42. For this reason, the positive electrode 43a and the outer structure 42 are not in contact. On the other hand, the outer diameter 43ba of the negative electrode 43b is larger than the inner diameter 42aa of the outer structure 42. For this reason, the negative electrode 43 b is in contact with the inner surface 42 a of the outer structure 42. Thereby, the negative electrode 43b is electrically connected to the outer structure 42. The outer diameter 43ba of the negative electrode 43b may be 100 μm larger than the inner diameter 42aa of the outer structure 42.

  The material of the current collector 47 is a conductive material including nickel-plated iron. The current collector 47 has a rod-shaped shaft portion 47a and a stop portion 47b attached to one end of the shaft portion 47a. The shaft portion 47a of the current collector 47 passes through the center of the electrode body 43 including the positive electrode 43a, the negative electrode 43b, and the separator 43c in the axial direction of the exterior body 45 (X direction in FIG. 18). The diameter of the hole 43ab provided in the center of the positive electrode 43a is smaller than the outer diameter of the shaft portion 47a. For this reason, the positive electrode 43a is in contact with the shaft portion 47a and is electrically connected to the shaft portion 47a. On the other hand, the diameter of the hole 43bb provided in the center of the negative electrode 43b is larger than the outer diameter of the shaft portion 47a. For this reason, since the negative electrode 43b is not in contact with the shaft portion 47a, it is electrically insulated from the shaft portion 47a.

  The electrode body 43 is disposed so as to be sequentially stacked on the stopper 47b of the current collector. The stopper 47 b prevents the electrode body 43 from dropping from the end of the current collector 47. Insulating push plates 44 a are disposed at both ends of the stacked electrode bodies 43. The pressing plate 44a prevents the electrode body 43 from being damaged when the electrode body 43 is stacked and pressed. The material of the pressing plate 44a may be any material suitable as an insulating material and a structural material. This material includes, for example, polypropylene. The shape of the stopper 47b is a disc shape. The stopping portion 47b does not contact the bulging portion 42b at the bottom of the outer structure. For this reason, the stopper 47b and the outer structure 42a are electrically insulated. The stopper portion 47b and the opposite end portion 47c of the shaft portion 47a pass through a hole 46d provided in the center of the lid member 46 and project outward (rightward in the figure) of the lid member 46. The shaft portion 47c penetrating the lid member 46 functions as a positive electrode terminal. The outer structure 42 functions as a negative electrode terminal. A hydrogen storage chamber 49 is provided in the inner space of the bulging portions 42b and 46b. That is, the hydrogen storage chamber 49 is arranged in a space inside the outer package surrounded by the inner surfaces 42ba and 46ba of the bulging portion and the electrode body 43.

  The fuel cell can be suitably used as an industrial and consumer power storage device.

DESCRIPTION OF SYMBOLS 1 Negative electrode case 2 Positive electrode case 3 Electrolytic solution 4 Negative electrode 5 Separator 6 Positive electrode 7 Oxygen storage chamber 8 Hydrogen storage chamber 9 Wall member 10 Exterior body 11 Negative electrode terminal 13 Electrolytic solution 14 Negative electrode 15 Separator 16 Positive electrode 17 Insulating member 18 Hydrogen storage chamber 19 Oxygen Storage chamber 25 Current collector plate 27 Blower fan 28 Hydrogen flow port 29 Connection portion 30 Oxygen flow port 31 Connection portion 32 Insulation connection member 33 Insulation connection member 34 Conductive connection member 35 Hydrogen gas first header 36 Oxygen gas first header 38 Hydrogen gas Second header 39 Oxygen gas second header 41 Donut battery 42 External structure (a: side, b: bulge)
43 electrode body (a: positive electrode, b: negative electrode, c: separator)
44 pressure plate 45 exterior body 46 lid member 47 current collector (a: shaft part, b: stopper part, c: screw part, d: end part)
48 Insulating seal member 49 Hydrogen storage chamber 51 Negative electrode case 52 Positive electrode case 53 Electrolytic solution 54 Negative electrode 55 Separator 56 Positive electrode 58 Hydrogen storage chamber 59 Oxygen storage chamber 61 Protective casing 62 Insulating casing 63 Negative electrode terminal 64 Positive electrode terminal 65 Step 66 Step 67 Insulating part 68 Lid member 69 Lid member 70 Mounting bolt 474 Wire 476 Breaker 477 Bus bar
478 Steel tower 71 Stacked battery 72 Cylindrical can (a: Side inner surface)
73 electrode body (a: positive electrode, b: negative electrode, c: separator)
74 Insulating plate 75 Exterior body 76 Lid member 77 Current collector (a: shaft part, b: stopper part, c: screw part, d: positive electrode terminal)
78 Bearing 81 Pipe battery 82 Circular tube (a: Inner surface)
83 Electrode body (a: positive electrode, b: negative electrode, c: separator)
85 Exterior body 86 Lid member 87 Current collector 88 Bearing 100 Outer shell 101 Body portion 102 Expanded portion 103 Packing 110 Positive electrode 120 Negative electrode 121 Hydrogen gas storage source 130 Separator 134 Current collector 135 Partition plates 136a and b Oxygen storage chamber 137 Electrolysis Liquid 138 Hydrogen storage chamber 211, 212 Flange 220, 221, 222 Piping 230 Salt concentration adjusting device 233 Reverse osmosis membrane 250 Oxygen concentration adjusting device 251 Oxygen storage source 260 Cooler 270 Pump 300 Exterior body 301 Circular tube 302 Lid member 310 Current collector Body 311 Nut 320 Positive electrode 321 Notch 330 Negative electrode 331 Gap 340 Separator 351, 352, 353 PP packing 365 Electrolyte inlet 361 Electrolyte supply source 363 Electrolyte adjustment chamber 364 Discharge passage 366 Electrolyte outlet 371 Hydrogen gas storage source 372 Hydrogen gas storage aisle 373 Hydrogen gas supply port 380 Hydrogen gas storage room

Claims (6)

A positive electrode comprising manganese dioxide;
A negative electrode containing a hydrogen storage material;
A separator interposed between the positive electrode and the negative electrode;
An electrolyte solution containing an alkaline aqueous solution,
A hydrogen storage chamber for storing hydrogen gas generated in the negative electrode;
An oxygen storage chamber for storing oxygen gas generated at the positive electrode, and a reversible fuel cell,
The negative electrode includes a hydrophobic material disposed on a surface in contact with the hydrogen storage chamber, and / or
The positive electrode includes a hydrophobic material disposed on a surface in contact with the oxygen storage chamber;
The hydrophobic material is carbon or Teflon (registered trademark).
Sealed reversible fuel cell. The reversible fuel cell according to claim 1, wherein the electrolyte is held in the oxygen storage chamber. The cylindrical positive electrode and the cylindrical negative electrode are arranged via the separator inside a cylindrical outer casing through a radial space, and contact the surface of the positive electrode opposite to the separator. The oxygen storage chamber is formed, and the hydrogen storage chamber is formed so as to contact the surface of the negative electrode opposite to the separator,
The oxygen storage chamber is disposed in the radial space, and the hydrogen storage chamber is disposed inward of the negative electrode, or
The reversible fuel cell according to claim 1, wherein the hydrogen storage chamber is disposed in the radial space, and the oxygen storage chamber is disposed inward of the positive electrode. A negative electrode terminal provided at one end in the axial direction of the exterior body and electrically connected to the negative electrode;
A positive electrode terminal provided at the other end in the axial direction of the exterior body and electrically connected to the positive electrode;
A protrusion provided on either the positive terminal or the negative terminal;
A hole provided in either the positive electrode terminal or the negative electrode terminal, and
The reversible fuel cell according to claim 3, wherein the protrusion and the hole can be fitted so that the two reversible fuel cells are connected in series. The reversible fuel cell according to claim 1,
A negative electrode case disposed in contact with the negative electrode and facing the positive electrode via a separator;
A positive electrode case disposed in contact with the positive electrode in contact with the negative electrode via the separator;
A hydrogen storage chamber is formed in a space between the negative electrode case and the negative electrode;
An oxygen storage chamber is formed in a space between the positive electrode case and the positive electrode, and is a reversible fuel cell in which unit cells are connected in series,
A positive electrode terminal in contact with the positive electrode of the unit cells connected in series;
A negative electrode terminal in contact with the negative electrode of the unit cells connected in series,
The positive electrode case of the unit cell and the negative electrode case of the adjacent unit cell are arranged so as to contact each other,
Reversible fuel cell. The reversible fuel cell according to claim 5, a metal wire, a structure, a circuit breaker capable of opening and closing, and a bus bar,
One end of the metal wire is attached to the reversible fuel cell, and the other end of the wire is attached to the structure, whereby a plurality of the reversible fuel cells are suspended from the structure. Can be lowered,
The reversible fuel cell module with which the positive electrode terminal and negative electrode terminal of the said reversible fuel cell which are adjacent are connected by the said bus bar via the said circuit breaker.

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