JP4009300B2 - FUEL CELL, ELECTRIC VEHICLE HAVING THE SAME, AND METHOD OF OPERATING FUEL CELL - Google Patents

Description

  The present invention relates to a fuel cell, an electric vehicle including the same, and a method for operating the fuel cell.

Solid polymer fuel cells have features such as high power generation efficiency and high current density, which can be reduced in size and weight, and can be started at room temperature due to low-temperature operation, and have a short startup time and easy handling. Research is continuing to apply to stationary power sources for vehicles and mobile power sources for spacecraft, submarines, ships, and automobiles.
However, since a polymer electrolyte fuel cell generates electric energy by supplying a fuel such as hydrogen to the fuel cell, when used as a mobile power source for automobiles, an ordinary gasoline automobile is used at a gas station. There is a problem in that refueling facilities have to be installed everywhere and fuel has to be replenished relatively frequently so as to replenish gasoline.
Therefore, focusing on the reverse reaction in which the fuel cell produces electrical energy, a regenerative fuel cell has been developed that integrates the function of a water electrolyzer that electrolyzes water to produce hydrogen as fuel. Yes.
As a conventional technique, Patent Document 1 describes a reversible function that includes a pair of power supply and current collectors and electrode plates arranged on both sides of an ion exchange membrane, functions as a fuel cell, and functions as a water electrolysis device. A reversible fuel cell vehicle equipped with a fuel cell and a hydrogen storage device for storing hydrogen to be supplied to the reversible fuel cell is disclosed.
(Patent Document 2) states that “a porous gas diffuser which is a constituent part of a solid polymer electrolyte type reversible cell having two functions of a water electrolytic cell and a fuel cell is an aggregate of fibers of a conductive substance. A fuel cell having a porous gas diffuser in which the surface of each fiber is coated with a fluororesin and the coating amount is in the range of 0.06 to 1.20 mg / cm ² with respect to the total surface area of the fiber. Is disclosed.
JP 2002-135911 A JP 2004-134134 A

However, the above conventional techniques have the following problems.
(1) In the technique disclosed in Patent Document 1, in the case where water electrolysis and fuel cell operation are alternately repeated in a reversible fuel cell, a large amount of water is fed into the power supply / current collector immediately after water electrolysis operation. Phenomenon of water, when hydrogen or oxygen gas is supplied to the power supply / current collector at the start of fuel cell operation, the water is clogged into the gas flow path of the power supply / current collector (flooding phenomenon) Has occurred, causing a voltage drop due to inhibition of diffusion of hydrogen gas and the like, resulting in a decrease in fuel cell performance.
(2) In the technique disclosed in (Patent Document 2), in order to prevent the flooding phenomenon immediately after the electrolysis operation of water, each fiber of the gas diffuser (power supply / current collector) is set to 0 with respect to the total surface area. Since the surface of the gas diffusion body is made hydrophobic by coating with a fluorine resin of .06 to 1.20 mg / cm ² to improve drainage, the flooding phenomenon can be suppressed to some extent and the voltage drop can be prevented. However, since the coating with the fluororesin is peeled off by repeated operation or the effect of maintaining hydrophobicity is deteriorated with time, there is a problem of lack of durability.
(3) The surface of the fiber of the gas diffuser must be coated with a fluororesin after the fluororesin dispersion is applied to the fiber and dried, and then heated at about 400 ° C. for 1 hour or longer to weld the fluororesin. There is a problem that it is complicated and lacks productivity. In addition, it is difficult to uniformly coat the surface of the fiber with the fluororesin by performing such treatment, and it is easy to cause spots, and it is difficult to remove water from the surface of the fiber not sufficiently coated with the fluororesin, There was a problem that the flooding phenomenon could not be completely prevented.
(4) During electrolysis of water, the electrode plate, gas diffuser, power supply / current collector are immersed in water, and the surface of the electrode plate, etc. undergoes a violent redox reaction. Components such as plates may elute into water, and the eluted components adhere to the surface of the electrolyte membrane, and the electromotive force of the fuel cell and the water electrolysis efficiency may decrease over time, resulting in lack of durability. Had problems.

The present invention solves the above-mentioned conventional problems, and when switching from the electrolysis of water to the operation of the fuel cell, only the presence of steam on the surface of the oxygen electrode prevents the flooding phenomenon. Providing high-efficiency fuel cells that are less susceptible to voltage drop due to diffusion inhibition, have superior operational stability, are simple in structure and light in weight, can be mass-produced at low cost, and have almost no electrode elution and excellent durability. The purpose is to do.
Further, the present invention can regenerate hydrogen (fuel) by power generation using hydrogen (fuel) and oxygen (air) and electrolysis of water in one fuel cell, and reduce the frequency of fuel replenishment. It is possible to improve the convenience and reduce the burden required for infrastructure development, and since the flooding phenomenon does not easily occur when switching from water electrolysis to fuel cell operation, voltage drop due to inhibition of oxygen diffusion is difficult to occur and stable. An object of the present invention is to provide an electric vehicle that can output and has excellent durability.
Further, according to the present invention, when oxygen or air is allowed to flow through the oxygen electrode chamber at the start of power generation operation of the fuel cell, only the vapor exists on the surface of the oxygen electrode, so that the flooding phenomenon is difficult to occur. Reduced electromotive force of the fuel cell due to adhesion of the eluting component to the electrolyte membrane because the electrode component does not elute in water or the amount of elution can be extremely small. Another object of the present invention is to provide a method of operating a fuel cell that does not cause a decrease in electrolysis efficiency and has excellent durability.

In order to solve the above-described conventional problems, the fuel cell of the present invention, the electric vehicle including the fuel cell, and the method of operating the fuel cell have the following configurations.
The fuel cell according to claim 1 of the present invention comprises: a. An electrolyte membrane; b. A hydrogen electrode chamber containing a hydrogen electrode disposed on one side of the electrolyte membrane; c. An oxygen electrode chamber containing an oxygen electrode disposed on the other surface of the electrolyte membrane; d. A hydrogen electrode chamber supply port and a hydrogen electrode chamber discharge port formed in the hydrogen electrode chamber; e. An oxygen electrode chamber supply port and an oxygen electrode chamber discharge port formed in the oxygen electrode chamber; f. An oxygen electrode chamber outlet opening / closing valve for opening and closing the oxygen electrode chamber outlet; g. A configuration and a voltage applying unit for electrolyzing the oxygen electrode chamber of the water applies a voltage the oxygen electrode chamber outlet on-off valve is closed between the hydrogen electrode and the oxygen electrode Yes.
With this configuration, the following effects can be obtained.
(1) At the time of electrolysis of water, an oxygen electrode chamber outlet opening / closing valve that opens and closes the oxygen electrode chamber outlet when water is supplied from the oxygen electrode chamber supply port to the oxygen electrode chamber and the oxygen electrode chamber is filled with water. closed and, when the voltage application unit oxygen electrode as an anode to apply a DC voltage between the oxygen electrode and the hydrogen electrode, the oxygen electrode _{H 2 O → 1 / 2O 2} + 2H + + 2e - reaction with oxygen occurs as To do. Protons (H ⁺ ) generated by this reaction move to the hydrogen electrode (cathode) side through the electrolyte membrane, receive electrons, and react as 2H ⁺ + 2e ⁻ → H ₂ to generate hydrogen. In addition, since the internal pressure of the oxygen electrode chamber is increased by oxygen generated at the oxygen electrode, water in the oxygen electrode chamber is pushed out of the oxygen electrode chamber from the oxygen electrode chamber supply port, and almost no liquid water is present around the oxygen electrode. It will not remain. Further, since the temperature of the oxygen electrode rises to about 85 to 95 ° C. due to the electrolysis of water, the liquid water slightly remaining on the surface of the oxygen electrode evaporates. For this reason, if oxygen or air is flowed into the oxygen electrode chamber at the start of power generation operation of the fuel cell, only the vapor exists on the surface of the oxygen electrode, so that the flooding phenomenon is difficult to occur, and the voltage drops due to the inhibition of oxygen diffusion. A difficult and highly efficient fuel cell can be obtained.
(2) A highly efficient fuel cell that has a simple structure, can be reduced in weight, is inexpensive, and can be mass-produced can be obtained.

  Here, as the electrolyte membrane, a fluorine resin-based ion exchange membrane having a sulfonic acid group or a carbonyl group is used.

  As an oxygen electrode, a titanium, platinum electrode, a surface of a substrate made of titanium, carbon, stainless steel, or the like formed with a film of platinum, ruthenium, iridium, etc., formed of platinum, platinum graphite, etc. What formed the film | membrane, such as ruthenium and iridium, on the surface of a base material can be used. In order to enhance gas permeability, those formed in a mesh shape or a porous shape are preferably used.

  As the hydrogen electrode, in addition to an electrode used as an oxygen electrode, a substrate in which a film made of platinum, ruthenium, iridium or the like is formed on the surface of a substrate made of nickel, iron, or the like can be used. In order to enhance gas permeability, those formed in a mesh shape or a porous shape are preferably used.

  The fuel cell comprises: a. An electrolyte membrane; b. A hydrogen electrode chamber; c. Using the oxygen electrode chamber as a single cell and using a stack in which the cells are stacked, the output per unit weight of the fuel cell can be increased.

The invention according to claim 2 of the present invention comprises: a. An electrolyte membrane; b. A hydrogen electrode chamber containing a hydrogen electrode disposed on one side of the electrolyte membrane; c. An oxygen electrode chamber containing an oxygen electrode disposed on the other surface of the electrolyte membrane; d. A hydrogen electrode chamber supply port and a hydrogen electrode chamber discharge port formed in the hydrogen electrode chamber; e. An oxygen electrode chamber supply port and an oxygen electrode chamber discharge port formed in the oxygen electrode chamber; f. An oxygen electrode chamber outlet opening / closing valve for opening and closing the oxygen electrode chamber outlet; h. A hydrogen electrode chamber outlet opening / closing valve for opening and closing the hydrogen electrode chamber outlet ; i. A voltage is applied between the hydrogen electrode and the oxygen electrode, and the oxygen electrode chamber in which the oxygen electrode chamber outlet opening / closing valve is closed and the water in the hydrogen electrode chamber in which the hydrogen electrode chamber outlet opening / closing valve is closed are closed. And a voltage application unit that electrolyzes .
With this configuration, in addition to the operation obtained in the first aspect, the following operation can be obtained.
(1) When electrolyzing water, the hydrogen electrode chamber outlet opening / closing valve opens and closes the hydrogen electrode chamber outlet when water is supplied from the hydrogen electrode chamber supply port to the hydrogen electrode chamber and the hydrogen electrode chamber is filled with water. , And the voltage application unit applies a DC voltage between the oxygen electrode and the hydrogen electrode to make the oxygen electrode an anode and the hydrogen electrode a cathode. At the oxygen electrode (anode), H ₂ O → 1 / 2O ₂ + 2H ⁺ It reacts like + 2e ⁻ to generate oxygen. Protons (H ⁺ ) generated by this reaction move to the hydrogen electrode (cathode) side through the electrolyte membrane, receive electrons, and react as 2H ⁺ + 2e ⁻ → H ₂ to generate hydrogen. Further, at the hydrogen electrode (cathode), hydrogen is generated by reaction as H ₂ O + e ⁻ → OH ⁻ + 1 / 2H ₂ . Further, since the internal pressure of the hydrogen electrode chamber is increased by hydrogen generated at the hydrogen electrode, the water in the hydrogen electrode chamber is pushed out of the hydrogen electrode chamber through the supply port of the hydrogen electrode chamber, and almost no liquid water is present around the hydrogen electrode. It will not remain. Further, since the temperature of the hydrogen electrode rises to about 85 to 95 ° C. due to the electrolysis of water, the liquid water slightly remaining on the surface of the hydrogen electrode evaporates. For this reason, when oxygen or air is allowed to flow through the oxygen electrode chamber and hydrogen is allowed to flow into the hydrogen electrode chamber at the start of operation of the fuel cell, only the steam exists on the surfaces of the oxygen electrode and the hydrogen electrode, so that the flooding phenomenon is unlikely to occur. A high-efficiency fuel cell is obtained in which voltage drop due to diffusion inhibition of oxygen and hydrogen hardly occurs.
(2) Since water is supplied to the hydrogen electrode chamber and water is electrolyzed even at the hydrogen electrode, the amount of hydrogen generated at the hydrogen electrode can be increased compared to when water is supplied only to the oxygen electrode chamber. , Hydrogen regeneration ability can be increased.

The invention according to claim 3 of the present invention is the fuel cell according to claim 1 or 2, wherein the oxygen electrode chamber communicates with the oxygen electrode chamber supply port formed on the lower end side of the oxygen electrode chamber. The first gas-liquid storage unit stores oxygen generated by electrolyzing the water and water pushed out from the oxygen electrode chamber.
With this configuration, in addition to the operation obtained in the first or second aspect, the following operation can be obtained.
(1) At the time of electrolysis of water, water stored in the first gas-liquid storage unit can be supplied to the oxygen electrode in a vapor state from the oxygen electrode chamber supply port, so that the water in the vapor state is electrolyzed at the oxygen electrode. can do. Since the oxygen electrode is not immersed in water, the component of the oxygen electrode does not elute in water or the amount of elution can be extremely small, so the electromotive force reduction and electrolysis efficiency of the fuel cell due to the eluting component adhering to the electrolyte membrane No deterioration occurs and excellent durability.
(2) At the time of power generation operation of the fuel cell, the first gas-liquid storage unit and the oxygen electrode chamber communicate with each other so that the stored water can humidify oxygen and allow the electrolyte membrane to absorb moisture. The proton conductivity of the fuel cell can be improved and the power generation performance of the fuel cell can be improved.

The invention according to claim 4 of the present invention is the fuel cell according to claim 2 or 3, wherein the hydrogen electrode chamber communicates with the hydrogen electrode chamber supply port formed on the lower end side of the hydrogen electrode chamber. The second gas-liquid storage unit stores hydrogen generated by electrolyzing the water and water pushed out from the hydrogen electrode chamber.
With this configuration, in addition to the operation obtained in the second or third aspect, the following operation can be obtained.
(1) When water is electrolyzed, water stored in the second gas-liquid storage part can be supplied to the hydrogen electrode in a vapor state from the hydrogen electrode chamber supply port, so that the water in the vapor state is electrolyzed at the hydrogen electrode. can do. Since the hydrogen electrode is not immersed in water, the component of the hydrogen electrode does not elute into the water or the amount of elution can be extremely small, so the electromotive force reduction and electrolysis efficiency of the fuel cell caused by the adhering component adhering to the electrolyte membrane No deterioration occurs and excellent durability.
(2) During power generation operation of the fuel cell, hydrogen can be humidified with the stored water by allowing the second gas-liquid storage part and the hydrogen electrode chamber to communicate with each other, so that the electrolyte does not need to be humidified with a humidifier. The proton conductivity of the membrane can be maintained.

An electric vehicle according to a fifth aspect of the present invention is the fuel cell according to any one of the first to fourth aspects, a hydrogen storage device that stores hydrogen to be supplied to the fuel cell, and a supply to the fuel cell. And a water storage tank for storing the water to be stored.
With this configuration, the following effects can be obtained.
(1) One fuel cell can generate power using hydrogen (fuel) and oxygen and regenerate hydrogen (fuel) by electrolysis of water, reducing the frequency of fuel replenishment and convenience As a result, it is possible to reduce the burden required for infrastructure development such as hydrogen production, transportation, storage and supply facilities.
(2) Since the flooding phenomenon is unlikely to occur at the time of switching from the electrolysis of water to the operation of the fuel cell, it is difficult to cause a voltage drop due to oxygen diffusion inhibition, and a stable output is obtained and the durability is also excellent.

  Here, as a hydrogen storage device, a storage tank for liquid hydrogen, a high-pressure tank made of metal or synthetic resin, or a hydrogen storage alloy that forms a metal hydride such as palladium, titanium, zirconium, magnesium, or a rare earth metal was used. Hydrogen storage devices, hydrogen storage devices using organic hydrides such as cyclohexane and decalin, hydrogen storage devices using carbon-based materials such as carbon nanotubes, fibrous carbon, and graphite can be used.

The invention according to claim 6 of the present invention comprises: a. An electrolyte membrane; b. A hydrogen electrode chamber containing a hydrogen electrode disposed on one side of the electrolyte membrane; c. An oxygen electrode chamber containing an oxygen electrode disposed on the other surface of the electrolyte membrane; d. A hydrogen electrode chamber supply port and a hydrogen electrode chamber discharge port formed in the hydrogen electrode chamber; e. An oxygen electrode chamber supply port and an oxygen electrode chamber discharge port formed in the oxygen electrode chamber; f. An oxygen electrode chamber outlet opening / closing valve for opening and closing the oxygen electrode chamber outlet; g. A method of operating a fuel cell, comprising: a voltage application unit that applies a voltage between the hydrogen electrode and the oxygen electrode to electrolyze water in the oxygen electrode chamber, in which the oxygen electrode chamber outlet opening / closing valve is closed And it has the structure which electrolyzes the water of the vapor | steam state in the said oxygen electrode chamber at the time of an electrolysis operation.
With this configuration, the following effects can be obtained.
(1) Since water in the vapor state is electrolyzed during the electrolysis operation, the oxygen electrode reacts as H ₂ O → 1 / 2O ₂ + 2H ⁺ + 2e ⁻ to generate oxygen. Protons (H ⁺ ) generated by this reaction move through the electrolyte membrane to the hydrogen electrode (cathode) side, receive electrons, react as 2H ⁺ + 2e ⁻ → H ₂ , and generate hydrogen in the hydrogen electrode chamber. be able to. Furthermore, if oxygen or air is allowed to flow into the oxygen electrode chamber at the start of power generation operation of the fuel cell, only the vapor exists on the surface of the oxygen electrode, so that the flooding phenomenon hardly occurs and the voltage drop due to the inhibition of oxygen diffusion hardly occurs. High electromotive force can be obtained stably.
(2) Since the oxygen electrode is not immersed in water during the electrolysis of water, the oxygen electrode components do not elute in water or the amount of elution can be extremely reduced, so the fuel caused by the eluting components adhering to the electrolyte membrane The battery has excellent durability without lowering electromotive force or electrolytic efficiency.

As described above, according to the fuel cell of the present invention, the electric vehicle including the fuel cell, and the operation method of the fuel cell, the following advantageous effects can be obtained.
According to the invention of claim 1,
(1) When switching from the electrolysis operation of water to the power generation operation of the fuel cell, since only the vapor exists on the surface of the oxygen electrode, the flooding phenomenon is unlikely to occur, so the voltage drop due to the oxygen diffusion inhibition is unlikely to occur. Thus, it is possible to provide a high-efficiency fuel cell having excellent operation stability and excellent durability.
(2) It is possible to provide a highly efficient fuel cell that is simple in structure and can be reduced in weight, can be mass-produced at low cost.

According to invention of Claim 2, in addition to the effect of Claim 1,
(1) When switching from water electrolysis operation to fuel cell power generation operation, only the presence of steam on the surface of the hydrogen electrode prevents flooding, so voltage drop due to inhibition of hydrogen diffusion is unlikely to occur. Thus, it is possible to provide a high-efficiency fuel cell having excellent operation stability and excellent durability.
(2) Since water is supplied to the hydrogen electrode chamber and water is electrolyzed even at the hydrogen electrode, the amount of hydrogen generated at the hydrogen electrode can be increased compared to when water is supplied only to the oxygen electrode chamber. A fuel cell having a high hydrogen regeneration capability can be provided.

According to invention of Claim 3, in addition to the effect of Claim 1 or 2,
(1) Since the oxygen electrode is not immersed in water during the electrolysis of water, the oxygen electrode component does not elute in water or the amount of elution can be extremely reduced, so the fuel caused by the elution component adhering to the electrolyte membrane It is possible to provide a fuel cell excellent in durability without causing a decrease in electromotive force or electrolytic efficiency of the battery.
(2) At the time of power generation operation of the fuel cell, the first gas-liquid storage unit and the oxygen electrode chamber communicate with each other so that the stored water can humidify oxygen and allow the electrolyte membrane to absorb moisture. Thus, it is possible to provide a fuel cell with improved proton conductivity and excellent power generation performance.

According to invention of Claim 4, in addition to the effect of Claim 2 or 3,
(1) Since the hydrogen electrode is not immersed in water at the time of electrolysis of water, the component of the hydrogen electrode does not elute in water or the amount of elution can be extremely reduced, so the fuel caused by the eluting component adhering to the electrolyte membrane It is possible to provide a fuel cell excellent in durability without causing a decrease in electromotive force or electrolytic efficiency of the battery.
(2) During power generation operation of the fuel cell, hydrogen can be humidified with the stored water by allowing the second gas-liquid storage part and the hydrogen electrode chamber to communicate with each other, so that the electrolyte does not need to be humidified with a humidifier. The proton conductivity of the membrane can be maintained, and a fuel cell having a simple structure can be provided.

According to the invention of claim 5,
(1) Hydrogen (fuel) can be regenerated by power generation using hydrogen (fuel) and oxygen and electrolysis of water in one fuel cell, reducing the frequency of fuel replenishment and convenience Since it is excellent and the frequency of hydrogen replenishment can be reduced, it is possible to provide an electric vehicle that can reduce the burden required for infrastructure development such as a hydrogen production plant, transportation, storage, and supply facilities.
(2) Since the flooding phenomenon is unlikely to occur at the time of switching from water electrolysis to fuel cell operation, a voltage drop due to oxygen diffusion inhibition is unlikely to occur, and a stable output can be obtained and an electric vehicle excellent in durability can be provided. can do.

According to the invention of claim 6,
(1) If oxygen or air is flowed into the oxygen electrode chamber at the start of power generation operation of the fuel cell, only the vapor exists on the surface of the oxygen electrode, so that flooding is unlikely to occur, and voltage drop occurs due to inhibition of oxygen diffusion. It is possible to provide a method of operating a fuel cell in which a difficult and high electromotive force can be stably obtained.
(2) Since the oxygen electrode is not immersed in water during the electrolysis of water, the oxygen electrode components do not elute in water or the amount of elution can be extremely reduced, so the fuel caused by the eluting components adhering to the electrolyte membrane It is possible to provide a method for operating a fuel cell that does not cause a decrease in electromotive force or electrolytic efficiency of the battery and has excellent durability.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a schematic diagram of a fuel cell according to Embodiment 1 of the present invention.
In the figure, 1 is a fuel cell according to the first embodiment, 2 is an electrolyte membrane formed of a fluororesin-based ion exchange membrane, 3 is formed of titanium, platinum, etc., and is disposed on one surface of the electrolyte membrane 2. The hydrogen electrode 4 is a hydrogen electrode chamber for accommodating the hydrogen electrode 3, 5 is an oxygen electrode made of titanium, platinum or the like and disposed on the other surface of the electrolyte membrane 2, and 6 is an oxygen for accommodating the oxygen electrode 5. An electrode chamber 7 is formed on the lower end side of the hydrogen electrode chamber 4, a hydrogen electrode chamber supply port through which hydrogen of fuel is supplied during power generation operation of the fuel cell 1 and moisture is supplied during electrolysis operation of water, and 8 is a hydrogen electrode chamber supply. A direction switching valve 9 comprising a three-way valve connected to the port 7 is a connecting pipe having one end connected to the direction switching valve 8. The direction switching valve 8 includes a hydrogen electrode chamber supply port 7, a connecting pipe 9, and a hydrogen (not shown). Connected to storage device. Reference numeral 10 denotes a directional switching valve composed of a three-way valve connected to the other end of the connecting pipe 9, and 11 denotes a communication pipe having one end connected to the directional switching valve 10. The directional switching valve 10 is connected to the connecting pipe 9, the communication pipe 11, and It is connected to a hydrogen storage device (not shown). Reference numeral 12 denotes a second gas-liquid storage unit connected to the other end of the communication pipe 11 and communicated with the hydrogen electrode chamber supply port 7 via the direction switching valves 8 and 10, and 13 has an upper end substantially the same as the height of the hydrogen electrode chamber 4. A hydrogen gas reservoir formed at the lower side of the second gas-liquid reservoir 12 and communicated with the other end of the communication pipe 11, and a water reservoir formed at the upper side of the second gas-liquid reservoir 12, 14 a is a communication hole formed at the bottom of the hydrogen gas storage unit 13 and communicated with the water storage unit 14, and 14 b is a partition plate standing on the hydrogen gas storage unit 13 between the communication hole 14 a and the communication pipe 11. A gap is formed between the upper end of the partition plate 14b and the upper end of the hydrogen gas storage unit 13, and hydrogen gas or the like flowing into the hydrogen gas storage unit 13 from the communication pipe 11 is directed upward along the partition plate 14b. Is stored in the hydrogen gas storage unit 13. Further, the volume of the water storage unit 14 is formed to be the same as or slightly larger than the volume of the hydrogen gas storage unit 13. An exhaust pipe 15 is connected to the upper end side of the water storage section 14 of the second gas-liquid storage section 12 and exhausts a gas such as hydrogen from the second gas-liquid storage section 12, and 16 is an exhaust pipe disposed in the exhaust pipe 15. The on-off valve 17 is connected to the upper end side of the water storage part 14 of the second gas-liquid storage part 12 to supply water to the second gas-liquid storage part 12, and 18 is disposed in the water supply pipe 17. A water supply pipe opening / closing valve 19 is formed on the upper end side of the hydrogen electrode chamber 4, and unreacted excess hydrogen is discharged during the power generation operation of the fuel cell 1, and water supplied to the hydrogen electrode chamber 4 at the start of water electrolysis operation. The hydrogen electrode chamber discharge port 20 is a hydrogen electrode chamber discharge port on / off valve connected to the hydrogen electrode chamber discharge port 19.

An oxygen electrode chamber supply port 21 is formed on the lower end side of the oxygen electrode chamber 6, and oxygen and air are supplied during power generation operation of the fuel cell 1 and moisture is supplied during water electrolysis operation, and 22 is connected to the oxygen electrode chamber supply port 21. A directional switching valve 23 comprising a three-way valve connected is a communication pipe having one end connected to the directional switching valve 22. The directional switching valve 22 includes an oxygen electrode chamber supply port 21, a communication pipe 23, and an oxygen such as a compressor (not shown). Connected to the supply device. Reference numeral 24 denotes a first gas-liquid storage part connected to the other end of the communication pipe 23 and communicated with the oxygen electrode chamber supply port 21 via the direction switching valve 22, and 25 denotes an upper end substantially the same as the height of the oxygen electrode chamber 6. The oxygen gas reservoir formed on the lower side of the first gas-liquid reservoir 24, 26 is a water reservoir formed on the upper side of the first gas-liquid reservoir 24, and 26a is on the bottom of the oxygen gas reservoir 25. A communication hole 26 b formed and communicated with the water storage unit 26 is a partition plate erected in the oxygen gas storage unit 25 between the communication hole 26 a and the communication pipe 23. A gap is formed between the upper end of the partition plate 26b and the upper end of the oxygen gas storage unit 25, and oxygen gas or the like flowing into the oxygen gas storage unit 25 from the communication pipe 23 is directed upward along the partition plate 26b. And then stored in the oxygen gas storage unit 25 . The volume of the water storage unit 26 is the same as or slightly larger than the volume of the oxygen gas storage unit 25. 27 is an exhaust pipe connected to the upper end side of the water storage section 26 of the first gas-liquid storage section 24 and exhausts a gas such as oxygen from the first gas-liquid storage section 24, and 28 is an exhaust pipe disposed in the exhaust pipe 27. The on-off valve 29 is connected to the upper end side of the water storage section 26 of the first gas-liquid storage section 24 and is a water supply pipe for supplying water to the first gas-liquid storage section 24, and 30 is disposed in the water supply pipe 29. A water supply pipe opening / closing valve 31 is formed on the upper end side of the oxygen electrode chamber 6 and is discharged together with water in which a gas such as unreacted oxygen is generated at the time of power generation operation of the fuel cell 1, and at the start of water electrolysis operation, the oxygen electrode chamber. 6 is an oxygen electrode chamber discharge port through which water supplied to 6 is discharged; 32, an oxygen electrode chamber discharge port on / off valve connected to the oxygen electrode chamber discharge port 31; and 33, a fuel connected to the hydrogen electrode 3 and the oxygen electrode 5 It is a load such as a motor that consumes electric energy generated by the battery 1.

With respect to the fuel cell according to Embodiment 1 of the present invention configured as described above, an operation method of water electrolysis operation and fuel cell power generation operation will be described with reference to the drawings.
FIG. 2 is a schematic diagram showing a state immediately before producing hydrogen as a fuel using the fuel cell as a water electrolysis device, and FIG. 3 is a schematic diagram showing a state immediately after the start of water electrolysis operation. FIG. 5 is a schematic diagram showing a state during electrolysis operation of water.
In the figure, reference numeral 34 denotes a voltage application unit that is connected to the hydrogen electrode 3 and the oxygen electrode 5 and applies a DC voltage using the hydrogen electrode 3 as a cathode and the oxygen electrode 5 as an anode.

When the fuel cell 1 is used as a water electrolyzer to produce hydrogen as a fuel by electrolyzing water, the direction switching valve 8 is switched so as to communicate with the hydrogen electrode chamber supply port 7 and the connecting pipe 9. 10 is switched to communicate with the connection pipe 9 and the communication pipe 11, the exhaust pipe opening / closing valve 16, the water supply pipe opening / closing valve 18, and the hydrogen electrode chamber discharge opening / closing valve 20 are opened, and water is supplied from the water supply pipe 17. When the gas / liquid storage unit 12 is supplied with water, the water is supplied from the communication hole 14 a, the hydrogen gas storage unit 13, the communication tube 11, the direction switching valve 10, the connection tube 9, and the direction switching valve 8 through the hydrogen electrode chamber supply port 7. It is supplied to the polar chamber 4. Since the upper end of the hydrogen gas reservoir 13 and the upper end of the hydrogen electrode chamber 4 are formed at substantially the same height, when the hydrogen electrode chamber 4 and the hydrogen gas reservoir 13 are filled with water, Since water overflows from the outlet 19, the hydrogen electrode chamber outlet opening / closing valve 20 is closed and the water supply pipe opening / closing valve 18 is closed to stop water supply (see FIG. 2). Similarly, on the oxygen electrode chamber 6 side, the direction switching valve 22 is switched so as to communicate with the oxygen electrode chamber supply port 21 and the communication pipe 23, and the exhaust pipe opening / closing valve 28, the water supply pipe opening / closing valve 30, and the oxygen electrode chamber discharge port opening / closing. When the valve 32 is opened and water is supplied from the water supply pipe 29 to the first gas-liquid storage section 24, water is supplied to the oxygen electrode chamber from the communication hole 26a, the oxygen gas storage section 25, the communication pipe 23, and the direction switching valve 22. It is supplied to the oxygen electrode chamber 6 through the port 21. Since the upper end of the oxygen gas storage unit 25 and the upper end of the oxygen electrode chamber 6 are formed at substantially the same height, when the oxygen electrode chamber 6 and the oxygen gas storage unit 25 are filled with water, the oxygen electrode chamber drainage is performed. Since water overflows from the outlet 31, the oxygen electrode chamber outlet opening / closing valve 32 is closed and the water supply pipe opening / closing valve 30 is closed to stop the supply of water. With the exhaust pipe opening / closing valves 16 and 28 opened, a DC voltage is applied between the hydrogen electrode 3 and the oxygen electrode 5 using the voltage application unit 34 so that the hydrogen electrode 3 becomes a cathode and the oxygen electrode 5 becomes an anode. When applied, the water in the hydrogen electrode chamber 4 and the oxygen electrode chamber 6 is electrolyzed, and the oxygen electrode 5 (anode) reacts as H ₂ O → 1 / 2O ₂ + 2H ⁺ + 2e ⁻ to generate oxygen. Proton (H ⁺ ) generated by this reaction moves through the electrolyte membrane 2 to the hydrogen electrode 3 (cathode) side, receives electrons, reacts as 2H ⁺ + 2e ⁻ → H ₂ , and reacts with hydrogen in the hydrogen electrode chamber 4. Is generated. Furthermore, the hydrogen electrode 3 (cathode) reacts as H ₂ O + e ⁻ → OH ⁻ + 1 / 2H ₂ to generate hydrogen in the hydrogen electrode chamber 4. Since the hydrogen electrode chamber discharge port opening / closing valve 20 is closed, the generated hydrogen increases the internal pressure of the hydrogen electrode chamber 4, and the water in the hydrogen electrode chamber 4 causes the hydrogen electrode chamber supply port 7 to flow as shown in FIG. It passes through and flows back into the second gas-liquid storage unit 12. In addition, since the oxygen electrode chamber outlet opening / closing valve 32 is also closed, the internal pressure of the oxygen electrode chamber 6 is increased by the generated oxygen, and the water in the oxygen electrode chamber 6 passes through the oxygen electrode chamber supply port 21 and the first gas. It flows backward into the liquid reservoir 24.
Further, when a DC voltage is continuously applied between the hydrogen electrode 3 and the oxygen electrode 5 using the voltage application unit 34, the water in the liquid state in the hydrogen electrode chamber 4 and the oxygen electrode chamber 6 as shown in FIG. Are pushed into the second gas-liquid storage unit 12 and the first gas-liquid storage unit 24, and hydrogen and oxygen are also filled in part of the hydrogen gas storage unit 13 and the oxygen gas storage unit 25. Further, when the voltage is continuously applied by the voltage application unit 34, the hydrogen gas storage unit 13 and the oxygen gas storage unit 25 are filled with hydrogen and oxygen, and the water storage units 14 and 26 are filled with hydrogen gas and oxygen gas from the communication holes 14a and 26a. Bubbles appear and are exhausted from the exhaust pipes 15 and 27. After dehumidifying and the like, they can be stored in a hydrogen storage device (not shown) and used for power generation of the fuel cell 1. In addition, since the volume of the water reservoir 14 is formed to be the same as or slightly larger than the volume of the hydrogen gas reservoir 13, the water in the water reservoir 14 is filled even when the hydrogen gas reservoir 13 is filled with hydrogen gas. Does not overflow from the second gas-liquid storage unit 12.

Further, in order to continue the electrolysis operation of water, the exhaust pipe opening / closing valve 16 is closed, and the direction changing valve 10 is switched to communicate with the connecting pipe 9, the connecting pipe 11, and a hydrogen storage device (not shown). The hydrogen electrode chamber 4, the connecting pipe 9, the connecting pipe 11, and the hydrogen gas storage section 13 are filled with hydrogen and water vapor or water, and the water storage section 14 that communicates with the hydrogen gas storage section 13 contains water. Therefore, moisture is continuously supplied from the water storage unit 14 to the hydrogen electrode chamber 4, and the supplied moisture is electrolyzed to generate hydrogen. Since the hydrogen storage device (not shown) communicates with the connection pipe 9 and the communication pipe 11 via the direction switching valve 10, the hydrogen in the connection pipe 9 and the communication pipe 11 is transferred to the hydrogen storage device using a pressure feeding device (not shown). Can be stored. When water in the second gas-liquid storage chamber 12 is reduced by electrolysis, the water supply pipe opening / closing valve 18 is opened to supply water.
On the other hand, on the oxygen electrode chamber 6 side, since the oxygen gas storage section 25 is filled with oxygen and steam, oxygen gas bubbles appear in the water storage section 26 from the communication hole 26a, and oxygen is exhausted from the exhaust pipe 27 to the outside of the system. The When water in the first gas-liquid storage chamber 24 is reduced by electrolysis, the water supply pipe opening / closing valve 30 is opened to supply water.

When starting the power generation operation of the fuel cell 1, the voltage application unit 34 is switched to the load 33, and then the direction change valve 10 on the hydrogen electrode chamber 4 side is switched to communicate with the connection pipe 9 and the communication pipe 11. The switching valve 8 is switched so as to communicate with the connecting pipe 9, the hydrogen electrode chamber supply port 7 and a hydrogen storage device (not shown), and the hydrogen electrode chamber outlet opening / closing valve 20 is opened. On the other hand, the direction switching valve 22 on the oxygen electrode chamber 6 side is switched so as to communicate with the oxygen electrode chamber supply port 21, the communication pipe 23, and an oxygen supply device (not shown), and the oxygen electrode chamber discharge port open / close valve 32 is opened to open the exhaust pipe. The on-off valve 28 is closed. Next, hydrogen flows from a hydrogen storage device (not shown) through the direction switching valve 8 and the hydrogen electrode chamber supply port 7 into the hydrogen electrode chamber 4, and from the oxygen supply device (not shown) through the direction switching valve 22 and the oxygen electrode chamber supply port 21. Then, oxygen is supplied into the oxygen electrode chamber 6. Thus, the hydrogen electrode 3 in _{^{H 2 → 2H + + 2e -}} , the oxygen electrode ^{_{5 1 / 2O 2 + 2H +}} + 2e - → H 2 O reaction occurs, power is generated. Unreacted hydrogen is discharged from the hydrogen electrode chamber outlet 19 to the outside of the hydrogen electrode chamber 4, and the generated water and unreacted oxygen are discharged from the oxygen electrode chamber outlet 31 to the outside of the oxygen electrode chamber 6.

As described above, since the fuel cell according to Embodiment 1 of the present invention is configured, the following operation can be obtained.
(1) At the time of electrolysis of water, water is supplied from the oxygen electrode chamber supply port 21 to the oxygen electrode chamber 6, and the oxygen electrode chamber discharge port 31 is opened and closed when the oxygen electrode chamber 6 is filled with water. The outlet opening / closing valve 32 is closed. On the other hand, water is also supplied from the hydrogen electrode chamber supply port 7 to the hydrogen electrode chamber 4, and when the hydrogen electrode chamber 4 is filled with water, the hydrogen electrode chamber discharge opening / closing valve 20 that opens and closes the hydrogen electrode chamber discharge port 19 is closed. When a DC voltage is applied between the oxygen electrode 5 and the hydrogen electrode 3, the oxygen generated in the oxygen electrode 5 increases the internal pressure of the oxygen electrode chamber 6. Water is pushed out of the oxygen electrode chamber 6 so that almost no liquid water remains around the oxygen electrode 5. Further, since the temperature of the oxygen electrode 5 rises to about 85 to 95 ° C. due to the electrolysis of water, the liquid water slightly remaining on the surface of the oxygen electrode 5 evaporates. Since the same phenomenon occurs on the hydrogen electrode chamber 4 side, when oxygen or air is supplied to the oxygen electrode chamber 6 and hydrogen is supplied to the hydrogen electrode chamber 4 at the start of power generation operation of the fuel cell 1, the surfaces of the oxygen electrode 5 and the hydrogen electrode 3 Since only vapor is present in the fuel cell, flooding is unlikely to occur, and voltage drop due to inhibition of diffusion of oxygen and hydrogen hardly occurs, and a highly efficient fuel cell can be obtained.
(2) During the electrolysis operation of water, the water stored in the first gas-liquid storage unit 24 can be supplied from the oxygen electrode chamber supply port 21 to the oxygen electrode 5 in a vapor state and supplied in a liquid state. Since water is also evaporated at the oxygen electrode 5 heated to 85 to 95 ° C., the oxygen electrode 5 can electrolyze water in a vapor state. Since the oxygen electrode 5 is not immersed in water, the component of the oxygen electrode 5 does not elute in water or the amount of elution can be extremely reduced, so that the electromotive force of the fuel cell 1 caused by the eluting component adhering to the electrolyte membrane 2 It has excellent durability without lowering or electrolytic efficiency.
(3) During the electrolysis operation of water, the water stored in the second gas-liquid storage unit 12 can be supplied from the hydrogen electrode chamber supply port 7 to the hydrogen electrode 3 in a vapor state and supplied in a liquid state. Since water is also evaporated at the hydrogen electrode 3 heated to 85 to 95 ° C., the hydrogen electrode 3 can electrolyze water in a vapor state. Since the hydrogen electrode 3 is not immersed in water, the components of the hydrogen electrode 3 do not elute in water or the amount of elution can be extremely reduced, so that the electromotive force of the fuel cell 1 caused by the elution component adhering to the electrolyte membrane 2 It has excellent durability without lowering or electrolytic efficiency.
(4) During power generation operation of the fuel cell 1, the first gas-liquid storage unit 24 and the oxygen electrode chamber 6 are in communication with each other so that oxygen is humidified with the stored water so that the electrolyte membrane 2 can absorb moisture. Therefore, the proton conductivity of the electrolyte membrane 2 can be improved and the power generation performance of the fuel cell 1 can be enhanced.
(5) During the power generation operation of the fuel cell 1, hydrogen can be humidified with the stored water by allowing the second gas-liquid storage unit 12 and the hydrogen electrode chamber 4 to communicate with each other, so that the hydrogen is not humidified with a humidifier. However, the proton conductivity of the electrolyte membrane 2 can be maintained.
(6) Since the exhaust pipes 15 and 27 provided with the exhaust pipe on-off valves 16 and 28 are connected to the water storage parts 14 and 26 of the first gas-liquid storage part 24 and the second gas-liquid storage part 12, During the water electrolysis operation, the exhaust pipe on-off valves 16 and 28 are opened, so that hydrogen gas is stored in the hydrogen gas storage section 13 and oxygen gas is stored in the oxygen gas storage section 25. Hydrogen can be stored. Further, during the power generation operation of the fuel cell, the hydrogen pipe chamber 4 and the oxygen electrode chamber 6 can be kept in a state filled with wet hydrogen or oxygen by closing the exhaust pipe opening / closing valves 16 and 28. , Can improve power generation performance.
(7) The volume of the water reservoirs 14 and 26 is formed to be the same as or slightly larger than the volumes of the hydrogen gas reservoir 13 and the oxygen gas reservoir 25, and the upper ends of the hydrogen gas reservoir 13 and the oxygen gas reservoir 25. And the hydrogen electrode chamber 4 and the upper end of the oxygen electrode chamber 6 are formed at substantially the same height, so that when the hydrogen electrode chamber 4 and the oxygen electrode chamber 6 are filled with water, When 30 is closed, even when the hydrogen gas storage unit 13 and the oxygen gas storage unit 25 are filled with hydrogen gas and oxygen gas by water electrolysis, the water in the water storage units 14 and 26 remains in the second gas-liquid storage unit 12. The hydrogen gas and oxygen gas can be reliably stored in the hydrogen gas storage unit 13 and the oxygen gas storage unit 25 without overflowing from the first gas-liquid storage unit 24.
(8) Since the partition plates 14b and 26b are erected in the hydrogen gas storage part 13 and the oxygen gas storage part 25, the hydrogen gas introduced into the hydrogen gas storage part 13 and the oxygen gas storage part 25 communicates with each other. The water does not leak immediately into the water reservoirs 14 and 26 through the holes 14a and 26a, and can be reliably stored in the hydrogen gas reservoir 13 and the oxygen gas reservoir 25.

Further, according to the method of operating the fuel cell in the first embodiment of the present invention, the following operation is obtained.
(1) Since water in the vapor state is electrolyzed during the electrolysis operation, hydrogen can be generated in the hydrogen electrode chamber 4. Furthermore, when oxygen or air is allowed to flow into the oxygen electrode chamber 6 and hydrogen is allowed to flow into the hydrogen electrode chamber 4 at the start of the power generation operation of the fuel cell 1, only steam exists on the surfaces of the hydrogen electrode 3 and the oxygen electrode 5. A flooding phenomenon is unlikely to occur, a voltage drop due to inhibition of diffusion of hydrogen or oxygen hardly occurs, and a high electromotive force can be stably obtained.
(2) Since the hydrogen electrode 3 and the oxygen electrode 5 are not immersed in water during electrolysis of water, the components of the hydrogen electrode 3 and the oxygen electrode 5 do not elute in water or the amount of elution can be extremely reduced. The durability of the fuel cell 1 due to the adhesion to the electrolyte membrane 2 does not decrease and electrolysis efficiency does not decrease.

(Embodiment 2)
FIG. 5 is a configuration diagram of the electric vehicle according to the second embodiment using the fuel cell according to the first embodiment. In addition, what was demonstrated in Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits description.
In the figure, 40 is an electric vehicle, 41 is a control unit that is connected to the hydrogen electrode 3 and the oxygen electrode 5 and controls the electric power generated in the fuel cell 1 and controls the switching between water electrolysis operation and power generation operation. This is a solar cell connected to the control unit 41. The electric power generated by the solar cell 42 is supplied to the control unit 41, and the surplus electric power is accumulated in the voltage application unit 34 made of a secondary battery. The control unit 41 is supplied with electric power from the solar cell 42 or the voltage application unit 34, supplies electric power generated in the fuel cell 1 to a load 33 such as a motor when the vehicle is running, and from the load 33 to the voltage application unit 34 when the vehicle is stopped. In the fuel cell 1, water is electrolyzed.
Reference numeral 43 denotes an oxygen supply device such as a compressor that is connected to the connecting pipe 23 and the oxygen electrode chamber supply port 21 via the direction switching valve 22 to pressurize the air, and 44 is a three-way valve connected to the hydrogen electrode chamber discharge opening / closing valve 20. A direction switching valve 45, an oxygen separator for separating oxygen from water communicated with the oxygen electrode chamber outlet 31 through the oxygen electrode chamber outlet opening / closing valve 32, 46 a direction switching valve 44, an oxygen separator 45, water A water storage tank 47 connected to the supply pipes 17 and 29, a hydrogen purification apparatus 47 connected to the exhaust pipe 15 and dehumidified and purified from water separated from the water in the second gas-liquid storage section 12, and 48 a hydrogen purification apparatus 47 is a pumping device such as a compressor that pumps hydrogen, 49 is a hydrogen storage device using a hydrogen storage alloy, organic hydride, carbon-based material, etc. 50 is connected to the hydrogen storage device 49 at one end and the direction is switched at the other end Connected to valve 8 The non-return valve 51 is connected to the direction switching valve 10 on the upstream side and connected to the hydrogen storage device 49 on the downstream side to pressurize the hydrogen and pump it to the hydrogen storage device 49. The other end is a bypass pipe connected to the downstream side of the check valve 50.

About the electric vehicle in Embodiment 2 comprised as mentioned above, the driving | running method is demonstrated below.
The control unit 41 applies a voltage to the hydrogen electrode 3 and the oxygen electrode 5 using the voltage application unit 34 when the automobile is stopped, electrolyzes water in the fuel cell 1, and produces hydrogen as fuel. Although the operation at this time is the same as that described in the first embodiment, only the main operation will be described.
Water is supplied from the water storage tank 46 to the second gas-liquid storage unit 12 and the first gas-liquid storage unit 24 through the water supply pipes 17 and 29, and the hydrogen electrode chamber supply port 7 and the oxygen electrode chamber supply port 21 are connected. Then, the hydrogen electrode chamber 4 and the oxygen electrode chamber 6 are supplied. When the supplied water overflows from the hydrogen electrode chamber outlet 19 and the oxygen electrode chamber outlet 31, the hydrogen electrode chamber outlet opening / closing valve 20 and the oxygen electrode chamber outlet opening / closing valve 32 are closed, and the water supply pipe opening / closing valves 18, 30 are closed. To stop the water supply. Water overflowing from the hydrogen electrode chamber outlet 19 is returned to the water storage tank 46 through the direction switching valve 44, and water overflowing from the oxygen electrode chamber outlet 31 is returned to the water storage tank 46 through the oxygen separator 45. It is.
When a voltage is applied to the hydrogen electrode 3 and the oxygen electrode 5, hydrogen and oxygen are generated in the hydrogen electrode chamber 4 and the oxygen electrode chamber 6, and the generated hydrogen and oxygen move out of the hydrogen electrode chamber 4 and the oxygen electrode chamber 6. Water is pushed out. The water flows back into the second gas-liquid storage part 12, and the hydrogen electrode chamber 4, the connecting pipe 9, the communication pipe 11 and a part of the second gas-liquid storage part 12 are filled with hydrogen and steam. The directional switching valve 10 is pumped and stored in the hydrogen storage device 49 through the pumping device 51. In addition, it is preferable to store the hydrogen purified through a hydrogen purifier such as a dehumidifier. Hydrogen overflowing from the second gas-liquid storage unit 12 is pumped and stored in the hydrogen storage device 49 from the exhaust pipe 15 through the hydrogen purification device 47. Hydrogen is continuously produced by supplying the water in the second gas-liquid storage unit 12 as wet steam into the hydrogen electrode chamber 4 and continuously electrolyzing the water in the vapor state. When the water in the 2nd gas-liquid storage part 12 runs short, it supplies from the water storage tank 46. FIG.
On the other hand, on the oxygen electrode chamber 6 side as well, water flows back into the first gas-liquid storage unit 24, and oxygen and steam are partially contained in the oxygen electrode chamber 6, the communication pipe 23 and the first gas-liquid storage unit 24. To charge. Oxygen overflowing from the first gas-liquid storage unit 24 is released from the exhaust pipe 27 into the atmosphere. The water in the first gas-liquid storage unit 24 is supplied into the oxygen electrode chamber 6 as wet steam, and the water in the vapor state is continuously electrolyzed. When the water in the 1st gas-liquid storage part 24 runs short, it supplies from the water storage tank 46. FIG.

  When the vehicle is running, the control unit 41 switches from the voltage application unit 34 to the load 33, and then supplies air and oxygen into the oxygen electrode chamber 6 through the direction switching valve 22 using the oxygen supply device 43 and the hydrogen storage device 49. Then, hydrogen is supplied into the hydrogen electrode chamber 4 through the check valve 50 and the direction switching valve 8. Thereby, the fuel cell 1 can generate electric power and supply electric power to the load 33. In addition, the surplus part of generated electric power is charged in the voltage application part 34 which consists of a secondary battery. Further, water (steam) generated in the oxygen electrode chamber 6 during the power generation operation is returned to the water storage tank 46 through the oxygen separator 45. In addition, excess hydrogen that is not used for the reaction in the hydrogen electrode chamber 4 during the power generation operation passes from the direction switching valve 44 through the bypass pipe 52 to the direction switching valve 8 and the hydrogen electrode chamber supply port 7 and returns to the hydrogen electrode chamber 4 again. Supplied.

As described above, since the electric vehicle according to Embodiment 2 of the present invention is configured, the following operation is obtained.
(1) With one fuel cell 1, hydrogen (fuel) can be regenerated by power generation operation and water electrolysis operation, the frequency of fuel replenishment can be reduced, and convenience can be improved. Since a flooding phenomenon is unlikely to occur when switching from electrolysis to power generation operation, a stable output is obtained in which voltage drop due to inhibition of diffusion of oxygen and hydrogen hardly occurs.

(Embodiment 3)
FIG. 6 is a schematic diagram of a fuel cell according to Embodiment 3 of the present invention. In addition, the thing similar to what was demonstrated in Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits description.
In the figure, 1a is the fuel cell according to Embodiment 3, and 10a is an on-off valve connected to the other end of the connecting pipe 9.
The difference between the fuel cell 1a in the third embodiment and the fuel cell 1 in the first embodiment is that the second gas-liquid storage unit 12 is not connected to the hydrogen electrode chamber 4 side.

With respect to the fuel cell according to Embodiment 3 of the present invention configured as described above, operations of water electrolysis operation and fuel cell power generation operation will be described with reference to the drawings.
FIG. 7 is a schematic diagram showing a state immediately before producing hydrogen of fuel using the fuel cell as a water electrolyzer, and FIG. 8 is a schematic diagram showing a state immediately after the start of electrolysis of water. FIG. 5 is a schematic diagram showing a state during electrolysis operation of water.

When the fuel cell 1 is used as a water electrolyzer to produce hydrogen as a fuel by electrolyzing water, the direction switching valve 22 is switched so as to communicate with the oxygen electrode chamber supply port 21 and the communication pipe 23, and the exhaust pipe is opened and closed. When the valve 28, the water supply pipe opening / closing valve 30, and the oxygen electrode chamber outlet opening / closing valve 32 are opened and water is supplied from the water supply pipe 29 to the first gas-liquid storage unit 24, the water is connected to the communication hole 26 a and oxygen gas storage. The oxygen is supplied to the oxygen electrode chamber 6 through the oxygen electrode chamber supply port 21 from the section 25, the communication pipe 23, and the direction switching valve 22. Since the upper end of the oxygen gas storage unit 25 and the upper end of the oxygen electrode chamber 6 are formed at substantially the same height, when the oxygen electrode chamber 6 and the oxygen gas storage unit 25 are filled with water, the oxygen electrode chamber drainage is performed. Since water overflows from the outlet 31, the oxygen electrode chamber outlet opening / closing valve 32 is closed and the water supply pipe opening / closing valve 30 is closed to stop water supply (see FIG. 7). In this state, when a DC voltage is applied between the hydrogen electrode 3 and the oxygen electrode 5 so that the hydrogen electrode 3 is a cathode and the oxygen electrode 5 is an anode, the water in the oxygen electrode chamber 6 is discharged. After being electrolyzed, the oxygen electrode 5 (anode) reacts as H ₂ O → 1 / 2O ₂ + 2H ⁺ + 2e ⁻ to generate oxygen. Proton (H ⁺ ) generated by this reaction moves through the electrolyte membrane 2 to the hydrogen electrode 3 (cathode) side, receives electrons, reacts as 2H ⁺ + 2e ⁻ → H ₂ , and reacts with hydrogen in the hydrogen electrode chamber 4. Is generated. Since the oxygen electrode chamber outlet opening / closing valve 32 is closed, the generated oxygen increases the internal pressure of the oxygen electrode chamber 6, and the water in the oxygen electrode chamber 6 passes through the oxygen electrode chamber supply port 21 to store the first gas-liquid. It flows backward into the part 24 (see FIG. 8).

Further, when a DC voltage is continuously applied between the hydrogen electrode 3 and the oxygen electrode 5 using the voltage application unit 34, all the water in the liquid state in the oxygen electrode chamber 6 is first gas as shown in FIG. The liquid is stored in the liquid storage unit 24 and part of the oxygen gas storage unit 25 is filled with oxygen. When the voltage is continuously applied by the voltage application unit 34, the oxygen gas storage unit 25 is filled with oxygen, oxygen gas bubbles appear in the water storage unit 26 from the communication hole 26 a, and are exhausted from the exhaust pipe 27. Since the volume of the water storage unit 26 is formed to be the same as or slightly larger than the volume of the oxygen gas storage unit 25, even when the oxygen gas storage unit 25 is filled with oxygen gas, the water in the water storage unit 26 is the first. The 1 gas-liquid storage part 24 does not overflow.
Since the oxygen electrode chamber 6, the communication pipe 23, and the oxygen gas storage unit 25 are filled with oxygen and water vapor, and the water storage unit 26 communicated with the oxygen gas storage unit 25 stores water. Wet steam is continuously supplied from the water reservoir 26 to the oxygen electrode chamber 6, and the supplied wet steam is electrolyzed to continuously supply oxygen to the oxygen electrode chamber 6 and hydrogen to the hydrogen electrode chamber 4. Generated. Since the hydrogen storage device (not shown) is in communication with the connecting pipe 9 via the on-off valve 10a, the on-off valve 10a is opened and the hydrogen in the connecting pipe 9 is transferred to the hydrogen storage device by using a pressure feeding device (not shown). Can be stored. When water in the first gas-liquid storage chamber 24 is reduced by electrolysis, the water supply pipe opening / closing valve 30 is opened to supply water.

When starting the power generation operation of the fuel cell 1a, after switching the voltage application unit 34 to the load 33, the direction changing valve 10a on the hydrogen electrode chamber 4 side is closed, and the direction switching valve 8 is connected to the hydrogen electrode chamber supply port 7 and It switches so that it may communicate with the hydrogen storage apparatus which is not shown in figure, and the hydrogen electrode chamber discharge port on-off valve 20 is opened. On the other hand, the direction switching valve 22 on the oxygen electrode chamber 6 side is switched so as to communicate with the oxygen electrode chamber supply port 21, the communication pipe 23, and an oxygen supply device (not shown), and the oxygen electrode chamber discharge port open / close valve 32 is opened to open the exhaust pipe. The on-off valve 28 is closed. Next, hydrogen flows from a hydrogen storage device (not shown) through the direction switching valve 8 and the hydrogen electrode chamber supply port 7 into the hydrogen electrode chamber 4, and from the oxygen supply device (not shown) through the direction switching valve 22 and the oxygen electrode chamber supply port 21. Then, oxygen is supplied into the oxygen electrode chamber 6. The hydrogen is supplied to the hydrogen electrode chamber 4 after being humidified by a humidifier (not shown). Thus, the hydrogen electrode 3 in _{^{H 2 → 2H + + 2e -}} , the oxygen electrode ^{_{5 1 / 2O 2 + 2H +}} + 2e - → H 2 O reaction occurs, power is generated. Unreacted hydrogen is discharged from the hydrogen electrode chamber outlet 19 to the outside of the hydrogen electrode chamber 4, and the generated water and unreacted oxygen are discharged from the oxygen electrode chamber outlet 31 to the outside of the oxygen electrode chamber 6.

As described above, since the fuel cell according to Embodiment 3 of the present invention is configured, in addition to the operations described in Embodiment 1, the following operations are obtained.
(1) Since it is only necessary to provide a mechanism for supplying water only to the oxygen electrode chamber 6 side, the apparatus configuration can be simplified, the number of parts can be reduced, and the size can be reduced.

(Embodiment 4)
FIG. 10 is a configuration diagram of an electric vehicle according to the fourth embodiment using the fuel cell according to the third embodiment. In addition, what was demonstrated in Embodiment 2 and Embodiment 3 attaches | subjects the same code | symbol, and abbreviate | omits description.
In the figure, 40a is an electric vehicle equipped with a fuel cell 1a, and 52a is a bypass pipe having one end connected to the hydrogen electrode chamber outlet opening / closing valve 20 and the other end connected to the downstream side of the check valve 50.

The operation of the electric vehicle according to Embodiment 4 configured as described above will be described below.
The control unit 41 applies a voltage to the hydrogen electrode 3 and the oxygen electrode 5 using the voltage application unit 34 when the automobile is stopped, electrolyzes water in the fuel cell 1, and produces hydrogen as fuel. Although the operation at this time is the same as that described in the third embodiment, only the main operation will be described.
Water is supplied from the water storage tank 46 through the water supply pipe 29 to the first gas-liquid storage unit 24, and is supplied to the oxygen electrode chamber 6 through the oxygen electrode chamber supply port 21. When the supplied water overflows from the oxygen electrode chamber outlet 31, the oxygen electrode chamber outlet on / off valve 32 is closed, the water supply pipe on / off valve 30 is closed, and the supply of water is stopped. The water overflowing from the oxygen electrode chamber outlet 31 is returned to the water storage tank 46 through the oxygen separator 45.
When a voltage is applied to the hydrogen electrode 3 and the oxygen electrode 5, hydrogen and oxygen are generated in the hydrogen electrode chamber 4 and the oxygen electrode chamber 6, and water is pushed out of the oxygen electrode chamber 6 by the generated oxygen. The water flows back into the first gas-liquid storage unit 24, and oxygen and the vapor are partially filled in the oxygen electrode chamber 6, the communication pipe 23, and a part of the first gas-liquid storage unit 24. Oxygen overflowing from the first gas-liquid storage unit 24 is released from the exhaust pipe 27 into the atmosphere. The water in the first gas-liquid storage unit 24 is supplied into the oxygen electrode chamber 6 as wet steam, and the water in the vapor state is continuously electrolyzed. When the water in the 1st gas-liquid storage part 24 runs short, it supplies from the water storage tank 46. FIG.
Hydrogen generated in the hydrogen electrode chamber 4 is pumped and stored in the hydrogen storage device 49 from the on-off valve 10a through the pumping device 51. In addition, it is preferable to store hydrogen purified by passing through a hydrogen purifier such as a dehumidifier or a hydrogen separator.

  When the vehicle is running, the control unit 41 switches from the voltage application unit 34 to the load 33, and then supplies air and oxygen into the oxygen electrode chamber 6 through the direction switching valve 22 using the oxygen supply device 43 and the hydrogen storage device 49. Then, hydrogen is supplied into the hydrogen electrode chamber 4 through the check valve 50 and the direction switching valve 8. Thereby, the fuel cell 1 can generate electric power and supply electric power to the load 33. In addition, the surplus part of generated electric power is charged in the voltage application part 34 which consists of a secondary battery. Further, water (steam) generated in the oxygen electrode chamber 6 during the power generation operation is returned to the water storage tank 46 through the oxygen separator 45. Excess hydrogen that is not used in the reaction in the hydrogen electrode chamber 4 during the power generation operation passes from the hydrogen electrode chamber outlet opening / closing valve 20 through the bypass pipe 52a, through the direction switching valve 8 and the hydrogen electrode chamber supply port 7 again. The hydrogen electrode chamber 4 is supplied.

  As described above, since the electric vehicle according to the fourth embodiment of the present invention is configured, the same operation as described in the second embodiment can be obtained.

Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited to these examples.
Example 1
In the fuel cell having the configuration described in the first embodiment, Nafion 115 (thickness 130 μm) manufactured by DuPont is used as an electrolyte membrane, and high-purity titanium (purity 99.99) manufactured by a crawl method as a hydrogen electrode and an oxygen electrode. Pure water was supplied to the hydrogen electrode chamber and the oxygen electrode chamber using a high purity titanium mesh of ˜99.999%, thickness 1 mm, size 25 mm ² ). After closing the hydrogen electrode chamber outlet opening / closing valve and the oxygen electrode chamber outlet opening / closing valve, electrolysis was performed by applying a DC voltage between the hydrogen electrode and the oxygen electrode from the current application unit. The voltage at this time is about 1.5 to 4.5 V, the current is about 0.5 to 2 A, and after the liquid water is pushed out from the hydrogen electrode chamber and oxygen electrode chamber, the hydrogen electrode chamber and oxygen Wet steam in the polar chamber was stably electrolyzed. One hour after the voltage was applied, the voltage application unit was replaced with a load consisting of a DC motor, and hydrogen gas and oxygen gas were supplied to the hydrogen electrode chamber and oxygen electrode chamber to start power generation operation. The electromotive force during the power generation operation was measured by disposing a 0.1Ω resistor in a part of the connection wiring to the load and measuring the voltage applied to the resistor. As a result, an electromotive force of 0.98 V (current 230 to 300 mA) was obtained immediately after the start of the power generation operation. After the power generation operation for 1 hour, the supply of hydrogen gas and oxygen gas to the hydrogen electrode chamber and oxygen electrode chamber was stopped, and then pure water was supplied into the hydrogen electrode chamber and oxygen electrode chamber. After closing the hydrogen electrode chamber outlet opening / closing valve and the oxygen electrode chamber outlet opening / closing valve, a DC voltage was applied between the hydrogen electrode and the oxygen electrode from the current application unit, and electrolysis was again performed for 1 hour. Thereby, after liquid water was pushed out from the hydrogen electrode chamber and the oxygen electrode chamber, the wet steam in the hydrogen electrode chamber and the oxygen electrode chamber was stably electrolyzed.
The above switching between the electrolysis operation and the power generation operation was performed for 10 cycles. In all cases, an electromotive force of 0.98 V was stably obtained immediately after the start of the power generation operation.

(Comparative Example 1)
Although the fuel cell described in Example 1 is used, the hydrogen electrode chamber outlet and the oxygen electrode chamber outlet on / off valve are opened, and the hydrogen electrode chamber and the oxygen electrode chamber supply port are connected to the hydrogen electrode chamber and the oxygen electrode chamber. Pure water was supplied to the oxygen electrode chamber, and a DC voltage was applied between the hydrogen electrode and the oxygen electrode from the current application unit to perform electrolysis. The voltage at this time was about 1.5 to 4.5 V, and the current was about 0.5 to 2 A. One hour after applying the voltage, the supply of pure water is stopped and the voltage application unit is replaced with a load consisting of a DC motor, and hydrogen gas and oxygen gas are supplied to the hydrogen electrode chamber and oxygen electrode chamber to start power generation operation. did. As a result, immediately after the start of the power generation operation, water is present in the hydrogen electrode chamber and the oxygen electrode chamber. Therefore, until the water is pushed out from the hydrogen electrode chamber and the oxygen electrode chamber, 0.98 V, which is the same as that in the first embodiment. The electromotive force was not obtained. After one hour of power generation operation, supply of hydrogen gas and oxygen gas to the hydrogen electrode chamber and oxygen electrode chamber is stopped and connection from the load to the voltage application unit is switched to supply pure water to the hydrogen electrode chamber and oxygen electrode chamber. A DC voltage was applied between the hydrogen application electrode and the oxygen electrode from the current application unit, and electrolysis was performed for 1 hour.
The above-described switching between the electrolysis operation and the power generation operation was performed for 10 cycles. However, as the number of cycles increased, the electromotive force during the power generation operation gradually decreased from 0.98 V, and at the 10th cycle, 0. The voltage dropped to 78V. This is presumed to be caused by a phenomenon in which water clogged in the gas flow path of the hydrogen electrode chamber and oxygen electrode chamber, making it difficult for the gas to flow (flooding phenomenon), resulting in a voltage drop due to inhibition of diffusion of hydrogen gas and oxygen gas. Is done.

  As described above, according to the present embodiment, when switching from the electrolysis operation of water to the power generation operation of the fuel cell, since only the steam exists on the surfaces of the oxygen electrode and the hydrogen electrode, the flooding phenomenon hardly occurs. It has been found that a high-efficiency fuel cell can be provided which is less likely to cause a voltage drop due to inhibition of diffusion of oxygen gas and hydrogen gas, has excellent operational stability and durability.

  The present invention relates to a fuel cell, an electric vehicle including the fuel cell, and a method for operating the fuel cell. When switching from the electrolysis of water to the operation of the fuel cell, only the steam exists on the surface of the oxygen electrode, and thus flooding Since the phenomenon is unlikely to occur, voltage drop due to inhibition of oxygen diffusion is unlikely to occur, the operation is stable, the structure is simple and lightweight, it can be mass-produced at low cost, and there is almost no electrode elution, and durability is also improved An excellent high-efficiency fuel cell can be provided, and hydrogen (fuel) can be regenerated by power generation using hydrogen (fuel) and oxygen (air) and electrolysis of water in one fuel cell. Therefore, it is possible to reduce the frequency of fuel replenishment, increase convenience, reduce the burden of infrastructure development, and reduce the amount of fuel when switching from water electrolysis to fuel cell operation. Since fading phenomenon hardly occurs, it is possible to provide an electric vehicle output voltage drop due to diffusion inhibition of the oxygen is to occur hardly stable is obtained excellent durability. In addition, if oxygen or air is allowed to flow into the oxygen electrode chamber at the start of power generation operation of the fuel cell, only the vapor exists on the surface of the oxygen electrode, so that the flooding phenomenon is unlikely to occur, and the voltage drop due to oxygen diffusion inhibition is unlikely to occur. High electromotive force can be obtained stably, and electrode components do not elute in water or the amount of elution can be extremely small, so the electromotive force of the fuel cell and electrolysis efficiency are reduced due to the elution components adhering to the electrolyte membrane. It is possible to provide a method of operating a fuel cell that does not generate a fuel and has excellent durability. This fuel cell can be widely used not only as a mobile power source for automobiles but also for a stationary power source for home use and a mobile power source for spacecraft, submarine and ship.

Schematic diagram of fuel cell in Embodiment 1 Schematic diagram showing a state immediately before producing hydrogen of fuel using a fuel cell as an electrolyzer for water Schematic showing the state immediately after the start of electrolysis of water Schematic diagram showing the state during electrolysis of water Configuration diagram of electric vehicle in Embodiment 2 Schematic diagram of fuel cell in Embodiment 3 Schematic diagram showing a state immediately before producing hydrogen of fuel using a fuel cell as an electrolyzer for water Schematic showing the state immediately after the start of electrolysis of water Schematic diagram showing the state during water electrolysis operation Schematic diagram showing the state in which fuel hydrogen is produced using the fuel cell as a water electrolyzer Configuration diagram of electric vehicle in Embodiment 4

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a Fuel cell 2 Electrolyte membrane 3 Hydrogen electrode 4 Hydrogen electrode chamber 5 Oxygen electrode 6 Oxygen electrode chamber 7 Hydrogen electrode chamber supply port 8 Directional switching valve 9 Connection pipe 10 Directional switching valve 10a On-off valve 11 Communication pipe 12 2nd gas liquid Storage part 13 Hydrogen gas storage part 14 Water storage part 14a Communication hole 14b Partition plate 15 Exhaust pipe 16 Exhaust pipe on / off valve 17 Water supply pipe 18 Water supply pipe on / off valve 19 Hydrogen electrode chamber outlet 20 Hydrogen electrode chamber outlet on / off valve 21 Oxygen electrode chamber supply port 22 Directional switching valve 23 Communication pipe 24 First gas-liquid storage section 25 Oxygen gas storage section 26 Water storage section 26a Communication hole 26b Partition plate 27 Exhaust pipe 28 Exhaust pipe on-off valve 29 Water supply pipe 30 Water supply pipe On-off valve 31 Oxygen electrode chamber outlet 32 Oxygen electrode chamber outlet on-off valve 33 Load 34 Voltage application unit 40, 40a Electric vehicle 41 Control unit 42 Solar cell 43 Oxygen supply device Device 44 Directional switching valve 45 Oxygen separator 46 Water storage tank 47 Hydrogen purification device 48 Pressure feeding device 49 Hydrogen storage device 50 Check valve 51 Pressure feeding device 52, 52a Bypass pipe

Claims (6)

a. An electrolyte membrane; b. A hydrogen electrode chamber containing a hydrogen electrode disposed on one side of the electrolyte membrane; c. An oxygen electrode chamber containing an oxygen electrode disposed on the other surface of the electrolyte membrane; d. A hydrogen electrode chamber supply port and a hydrogen electrode chamber discharge port formed in the hydrogen electrode chamber; e. An oxygen electrode chamber supply port and an oxygen electrode chamber discharge port formed in the oxygen electrode chamber; f. An oxygen electrode chamber outlet opening / closing valve for opening and closing the oxygen electrode chamber outlet; g. A voltage application unit that applies a voltage between the hydrogen electrode and the oxygen electrode and electrolyzes water in the oxygen electrode chamber in which the oxygen electrode chamber outlet opening / closing valve is closed ; Fuel cell. a. An electrolyte membrane; b. A hydrogen electrode chamber containing a hydrogen electrode disposed on one side of the electrolyte membrane; c. An oxygen electrode chamber containing an oxygen electrode disposed on the other surface of the electrolyte membrane; d. A hydrogen electrode chamber supply port and a hydrogen electrode chamber discharge port formed in the hydrogen electrode chamber; e. An oxygen electrode chamber supply port and an oxygen electrode chamber discharge port formed in the oxygen electrode chamber; f. An oxygen electrode chamber outlet opening / closing valve for opening and closing the oxygen electrode chamber outlet; h. A hydrogen electrode chamber outlet opening / closing valve for opening and closing the hydrogen electrode chamber outlet ; i. A voltage is applied between the hydrogen electrode and the oxygen electrode, and the oxygen electrode chamber in which the oxygen electrode chamber outlet opening / closing valve is closed and the water in the hydrogen electrode chamber in which the hydrogen electrode chamber outlet opening / closing valve is closed are closed. And a voltage application unit that electrolyzes the fuel cell. A first air that stores oxygen that is generated by electrolyzing water in the oxygen electrode chamber and water that is pushed out of the oxygen electrode chamber, in communication with the oxygen electrode chamber supply port formed on the lower end side of the oxygen electrode chamber. The fuel cell according to claim 1, further comprising a liquid storage unit. A second gas that communicates with the hydrogen electrode chamber supply port formed on the lower end side of the hydrogen electrode chamber and stores hydrogen generated by electrolyzing water in the hydrogen electrode chamber and water pushed out of the hydrogen electrode chamber. The fuel cell according to claim 2, further comprising a liquid storage unit.   A fuel cell according to any one of claims 1 to 4, a hydrogen storage device for storing hydrogen supplied to the fuel cell, and a water storage tank for storing water supplied to the fuel cell. An electric vehicle characterized by a. An electrolyte membrane; b. A hydrogen electrode chamber containing a hydrogen electrode disposed on one side of the electrolyte membrane; c. An oxygen electrode chamber containing an oxygen electrode disposed on the other surface of the electrolyte membrane; d. A hydrogen electrode chamber supply port and a hydrogen electrode chamber discharge port formed in the hydrogen electrode chamber; e. An oxygen electrode chamber supply port and an oxygen electrode chamber discharge port formed in the oxygen electrode chamber; f. An oxygen electrode chamber outlet opening / closing valve for opening and closing the oxygen electrode chamber outlet; g. A method of operating a fuel cell, comprising: a voltage application unit that applies a voltage between the hydrogen electrode and the oxygen electrode to electrolyze water in the oxygen electrode chamber, in which the oxygen electrode chamber outlet opening / closing valve is closed Because
A method for operating a fuel cell, comprising electrolyzing water in a vapor state in the oxygen electrode chamber during electrolysis.

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