Fuel cell unit

Abstract

To provide a fuel cell unit capable of reducing power generation cost.SOLUTION: In power generation, a control unit 9 controls an on-off valve 8, and a switching valve 7 in either a first control mode where the control unit activates a pump 2 while controlling the on-off valve to transit into a closed state to close a pipe 5w, and controlling the switching valve to connect a suction port 2i of the pump 2 to a gas-liquid separation tank 3, thereby flowing new first gas into a separator 11 by allowing the pump 2 to suck first gas from the separator 11 via the gas-liquid separation tank 3 or a second control mode where the control unit activates the pump 2 while controlling the on-off valve 8 to transit into an open state to open the pipe 5w, and controlling the switching valve 7 to connect an exhaust port 2o of the pump 2 to the gas-liquid separation tank 3, thereby pumping the first gas from the pump 2 to the separator 11 via the gas-liquid separation tank 3 and pumping water separated in the gas-liquid separation tank 3 from the gas-liquid separation tank 3 to a fuel supply device through the pipe 5w.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell unit configured to be capable of generating electricity by reacting a first gas containing an oxidant with a second gas containing hydrogen. [Background technology]

[0002] For example, the following patent document discloses an energy supply system (hereinafter, also simply referred to as "the system") configured to enable hydrogen and oxygen generated in a hospital to be utilized in hospitals, hydrogen stations, homes, etc. Specifically, this system is configured to include a power generation unit that generates electricity (performs solar power generation), a pure water storage unit that stores water (pure water) generated by an electrically regenerative pure water generation device, an electrolysis device that electrolyzes water using the electricity generated in the power generation unit, a hydrogen tank that stores hydrogen generated in the electrolysis device, an oxygen tank that stores oxygen generated in the electrolysis device, a fuel cell that generates electricity using hydrogen, and an oxygen supply device that provides oxygen for oxygen inhalation.

[0003] In this case, the hydrogen produced in the electrolyzer is supplied to a hydrogen station, which is a hydrogen supply facility, and stored in a hydrogen tank, and is then supplied from the hydrogen station to a fuel cell for power generation. Also, the oxygen produced in the electrolyzer is stored in an oxygen tank of an oxygen supply device and used for medical purposes in the hospital. In this way, this system makes it possible to effectively utilize the oxygen obtained by electrolysis of water in the electrolyzer together with the hydrogen. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-047417 A (Pages 3-5, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0005] However, the system disclosed in the above-mentioned patent document has the following problems to be solved.

[0006] Specifically, the above system employs a configuration in which water (pure water) produced by an electrically regenerated pure water production device is stored in a pure water storage section, and the stored water is supplied to an electrolysis device for electrolysis to obtain hydrogen to be used in power generation in a fuel cell. In this case, the system employs a configuration in which the electrically regenerated pure water production device produces water (pure water) to be used as a raw material in an electrolysis device that produces hydrogen to be used in a fuel cell for power generation. In other words, this system consumes electricity when producing water to obtain hydrogen required for power generation, which causes a problem in that the cost of producing hydrogen rises sharply, making it difficult to reduce power generation costs.

[0007] On the other hand, in the fuel cell in the above system, a large amount of water is generated on the cathode electrode side of the membrane electrode assembly by reacting oxygen and hydrogen during power generation, and this water is discharged from the fuel cell together with the exhaust gas. Therefore, the applicant attempted a power generation method in which this water discharged together with the exhaust gas is recovered and used as a raw material for hydrogen generation. As a result, it became possible to reduce the power generation cost (hydrogen generation cost) by the amount of electricity not required to generate the raw material water, compared to the configuration of the above system in which hydrogen is generated using water generated by an electrically regenerated pure water generation device as a raw material.

[0008] However, in the power generation method attempted by the applicant, the work of transporting the collected water in a transport container or the like and injecting it into the hydrogen generation device is cumbersome, and if a liquid transfer pump or the like is provided to automate this process, electricity will be used to supply water to the hydrogen generation device. Therefore, this point needs to be improved in order to use the wastewater from the power generation cell as a raw material for hydrogen generation.

[0009] The present invention has been made in view of the above-mentioned problems, and has as its main object to provide a fuel cell unit that can sufficiently reduce power generation costs without requiring complicated operations. [Means for solving the problem]

[0010] In order to achieve the above object, a fuel cell unit according to claim 1 includes a fuel cell main body including a first separator through which a first gas containing an oxidant is passed, a second separator through which a second gas containing hydrogen is passed, and a flat plate-shaped laminated object including at least a membrane electrode assembly disposed between the first separator and the second separator, laminated and integrated together, and configured to generate electricity by reacting the first gas with the second gas via the membrane electrode assembly, a pump for supplying the first gas to the first separator, and a fuel cell main body for electrolyzing raw water to produce a pre-oxidized water. a fuel cell unit including a fuel supply device that generates the hydrogen to generate the second gas and supplies the generated second gas to the second separator, the fuel cell unit including: a gas-liquid separation tank disposed between the first separator and the pump for separating and recovering water contained in exhaust gas discharged from the first separator, a connection switching device that selectively connects either an intake port or an exhaust port of the pump to the gas-liquid separation tank; and a first pipe that supplies the water separated in the gas-liquid separation tank to the fuel supply device as the raw material. The fuel cell system includes a first valve mechanism disposed in the first piping, and a control unit that controls the pump, the connection switching device, and the first valve mechanism, and when generating power in the fuel cell main body, the control unit controls the first valve mechanism to transition to a closed state in which the first piping is blocked, and controls the connection switching device to operate the pump in a state in which the intake port of the pump is connected to the gas-liquid separation tank, thereby causing the pump to suck in the first gas from the first separator via the gas-liquid separation tank, thereby producing new first gas. and a second control mode in which the first gas is pumped from the pump to the first separator via the gas-liquid separation tank and water separated in the gas-liquid separation tank is pumped from the pump to the first separator via the gas-liquid separation tank and water separated in the gas-liquid separation tank is pumped from the gas-liquid separation tank to the fuel supply device via the first piping by controlling the first valve mechanism to transition to an open state in which the first piping is opened and controlling the connection switching device to operate the pump in a state in which the exhaust port of the pump is connected to the gas-liquid separation tank,The connection switching device and the first valve mechanism are configured to be controllable.

[0011] The fuel cell unit according to claim 2 is the fuel cell unit according to claim 1, further comprising: a second pipe for supplying the second gas from the fuel supply device to the second separator; a third pipe connecting an exhaust port in the second separator to the gas-liquid separation tank; a second valve mechanism for restricting / allowing an inflow of the first gas into the second pipe; and a third valve mechanism disposed in the third pipe, wherein the control unit, when performing control in the first control mode and the second control mode, controls the second valve mechanism to restrict the inflow of the first gas into the second pipe and controls the third valve mechanism to transition to a closed state in which the third pipe is blocked, and when a predetermined condition is satisfied in a state in which the fuel cell main body is not generating power, controls the second valve mechanism to restrict / allow an inflow of the first gas into the second pipe and controls the third valve mechanism to transition to a closed state in which the third pipe is blocked, the first valve mechanism to transition to the closed state, the second valve mechanism to allow the inflow of the first gas into the second piping, and the third valve mechanism to transition to an open state in which the third piping is opened, and the connection switching device to operate the pump in a state in which the intake port of the pump is connected to the gas-liquid separation tank, thereby causing the pump to suck the first gas from the second separator through the gas-liquid separation tank and the third piping, thereby separating and recovering water contained in the first gas exhausted from the second separator in the gas-liquid separation tank. Effect of the Invention

[0012] In the fuel cell unit described in claim 1, the control unit is configured to be able to control the pump, the connection switching device and the first valve mechanism in either a first control mode in which, when generating power in the fuel cell main body, the control unit controls the first valve mechanism to transition to a closed state in which the first piping is blocked, and controls the connection switching device to operate the pump in a state in which the intake port of the pump is connected to the gas-liquid separation tank, thereby causing the pump to suck in the first gas from the first separator through the gas-liquid separation tank and causing new first gas to flow into the first separator, or a second control mode in which the control unit controls the first valve mechanism to transition to an open state in which the first piping is opened, and controls the connection switching device to operate the pump in a state in which the exhaust port of the pump is connected to the gas-liquid separation tank, thereby pressure-feeding the first gas from the pump to the first separator through the gas-liquid separation tank and pressure-feeding water separated in the gas-liquid separation tank from the gas-liquid separation tank to the fuel supply device via the first piping.

[0013] Therefore, according to the fuel cell unit described in claim 1, unlike the configuration in which the water (pure water) used as a raw material in the electrolysis device for generating hydrogen is generated by an electric regenerative pure water generator, by controlling each part in the first control mode, the water discharged from the fuel cell main body (first separator) during power generation is separated and collected in the gas-liquid separation tank, and this water can be used as a raw material for generating hydrogen in the fuel supply device, and the cost of generating hydrogen can be sufficiently reduced by the amount of electricity not required for generating the raw water. In addition, by controlling each part in the second control mode, it is possible to pressure-feed the water in the gas-liquid separation tank from the gas-liquid separation tank to the fuel supply device while continuing power generation, without transporting the water collected in the gas-liquid separation tank with a transport container or the like and injecting it into the fuel supply device, or arranging a liquid feed pump or the like for pressure-feeding water from the gas-liquid separation tank to the fuel supply device, and therefore the cost of generating hydrogen can be further reduced. As a result, the cost of generating electricity using hydrogen generated in the fuel supply device can be sufficiently reduced.

[0014] In the fuel cell unit according to claim 2, when the control unit performs control in the first control mode and the second control mode, the control unit controls the second valve mechanism to restrict the inflow of the first gas into the second pipe, and controls the third valve mechanism to transition to a closed state in which the third pipe is blocked, and when a predetermined condition is satisfied in a state in which the fuel cell main body is not generating power, the control unit controls the first valve mechanism to transition to a closed state, controls the second valve mechanism to allow the inflow of the first gas into the second pipe, and controls the third valve mechanism to The pump, the connection switching device, the first valve mechanism, the second valve mechanism and the third valve mechanism are configured to be controllable in a third control mode in which the pump is operated in a state in which the third piping is transitioned to an open state in which the third piping is opened, and the connection switching device is controlled to connect the intake port of the pump to the gas-liquid separation tank, thereby causing the pump to suck in the first gas from the second separator through the gas-liquid separation tank and the third piping, and thereby separating and recovering water contained in the first gas discharged from the second separator in the gas-liquid separation tank.

[0015] Therefore, according to the fuel cell unit described in claim 2, not only can a sufficient amount of water be secured for use as a raw material in the fuel supply device, but it is also possible to preferably avoid a state in which a large amount of water droplets (liquid phase water) discharged from the fuel supply device together with the second gas generated in the fuel supply device, or water droplets (liquid phase water) generated by condensation are present in the second separator, thereby preventing the passage resistance of the second gas supplied during power generation from becoming excessively large, thereby enabling power generation to be performed efficiently in the fuel cell main body. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a diagram showing the configuration of a fuel cell unit 1, and is an explanatory diagram for explaining an operation mode in which wastewater from a separator 11 is collected in parallel with power generation in a fuel cell 10. [Diagram 2] FIG. 2 is an explanatory diagram illustrating an operation mode in which recovered water is supplied to a hydrogen generation device 20 in parallel with power generation in a fuel cell 10. [Diagram 3]FIG. 2 is an explanatory diagram illustrating an operation mode in which water is collected from a separator 12 of a fuel cell 10 when power generation is not being performed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a fuel supply device and a fuel cell unit will be described with reference to the accompanying drawings.

[0018] The fuel cell unit 1 shown in Fig. 1 is an example of a "fuel cell unit" and is configured to generate electricity by reacting gases for power generation (air (atmosphere: oxygen), which is an example of a "first gas containing an oxidant," and hydrogen gas, which is an example of a "second gas containing hydrogen"). Specifically, the fuel cell unit 1 includes a pump 2, a gas-liquid separation tank 3, a post-treatment device 4, pipes 5a-5j, 5w, switching valves 6a-6d, 7, an on-off valve 8, a control unit 9, a fuel cell 10, and a hydrogen generation device 20.

[0019] In this case, the fuel cell 10 is an example of a "fuel cell body configured to generate electricity by reacting a first gas with a second gas," and includes a power generation stack made up of separator 11, which is an example of a "first separator," separator 12, which is an example of a "second separator," and MEA 13, which is an example of a "membrane electrode assembly (membrane electrode assembly for fuel cells)," a separator (not shown) for passing a cooling fluid (air or coolant), and end plates (not shown) disposed at both ends in the stacking direction of each laminate. In this example, the plates such as separators 11 and 12, MEA 13, the cooling separator, and the end plates correspond to "plural flat plate-shaped laminated objects," and the fuel cell 10 is configured by stacking and integrating these.

[0020] Separator 11 has a groove (not shown) for passing air (atmosphere), and separator 12 has a groove (not shown) for passing hydrogen gas, and these are laminated so that MEA 13 is sandwiched between separators 11 and 12. As a result, air flow path 11c is formed by the groove of separator 11 and one surface of MEA 13, and separator 11 functions as an anode (air electrode: oxygen electrode), and hydrogen flow path 12c is formed by the groove of separator 12 and the other surface of MEA 13, and separator 12 functions as a cathode (hydrogen electrode). MEA 13 is composed of an electrolyte membrane, a catalyst layer, a gas diffusion layer, and the like.

[0021] In addition, an actual fuel cell 10 is configured to include multiple of the above-mentioned power generation stacks and cooling separators depending on the power generation capacity required of the fuel cell unit 1, but in order to facilitate understanding of the configuration and operation of the fuel cell unit 1, only one power generation stack is shown, and illustrations and descriptions of the cooling separators and end plates are omitted.

[0022] The hydrogen generating device 20 is an example of a "fuel supply device" and is configured to generate hydrogen by electrolyzing water as a "raw material" and to supply the generated hydrogen (hydrogen gas) to the separator 12 of the fuel cell 10 as a "second gas: fuel". In this case, when generating electricity in the fuel cell 10, air (oxygen) passing through the air flow path 11c reacts with hydrogen gas (hydrogen) passing through the hydrogen flow path 12c to generate water in the air flow path 11c, and this water is discharged from the separator 11 together with the exhaust gas. In addition, moisture in the hydrogen gas may condense in the hydrogen flow path 12c due to heat exchange with the fuel cell 10 (separator 12) which is at a low temperature (room temperature) immediately after the start of operation, or heat exchange with air passing through the air flow path 11c and a refrigerant passing through a cooling separator, and this water may be discharged from the separator 12 together with the exhaust gas.

[0023] Furthermore, in the fuel cell unit 1 of this example, which generates electricity in the fuel cell 10 using hydrogen (hydrogen gas) generated by electrolysis in the hydrogen generation device 20 as fuel, a small amount of water (water that is not electrolyzed) is discharged from the hydrogen generation device 20 together with the hydrogen gas, and this water may flow into the separator 12 together with the hydrogen gas and be discharged from the separator 12 together with the exhaust air. Therefore, in the fuel cell unit 1 of this example, as described below, a configuration is adopted in which this water is recovered in the gas-liquid separation tank 3 and the recovered water is supplied to the hydrogen generation device 20 as a "raw material" to generate hydrogen.

[0024] On the other hand, the pump 2 is an example of a "pump that supplies a first gas to the first separator", and sucks air from the air flow path 11c of the separator 11 and pumps air into the air flow path 11c (supplies air to the separator 11) under the control of the control unit 9. As will be described later, the fuel cell unit 1 of this example employs a configuration in which the pump 2 pumps air to pump (supply) water recovered from the separator 11 (air flow path 11c) to the hydrogen generation device 20.

[0025] The gas-liquid separation tank 3 is an example of "a gas-liquid separation tank which separates and recovers water contained in the exhaust gas discharged from the first separator" and, as described below, is disposed between the separator 11 and the pump 2 in the fuel cell 10 to allow the passage of air flowing from the separator 11 toward the pump 2, and air flowing from the pump 2 toward the separator 11.

[0026] The post-treatment device 4 is composed of a recovery device that removes (recovers) hydrogen contained in the gas (exhaust containing unreacted hydrogen in the fuel cell 10) that is exhausted from the separator 12 after being reacted with air (oxygen) in the air flow path 11c in the hydrogen flow path 12c of the separator 12, and a mixer that mixes air (atmosphere) (diluting the exhaust from the separator 12) so that the hydrogen concentration in the gas exhausted from the separator 12 falls below a predetermined value. Note that when the hydrogen concentration in the exhausted gas is sufficiently low, the post-treatment device 4 may be unnecessary.

[0027] The pipe 5a is connected to the pipe connection 11a of the separator 11, and one end of the pipe 5b is connected to the atmosphere. The pipe 5b is an example of a "second pipe for supplying a second gas from a fuel supply device to a second separator", and one end of the pipe 5b is connected to a hydrogen gas outlet of the hydrogen generation device 20, and the other end of the pipe 5c is connected to the pipe connection 11b of the separator 11, and the other end of the pipe 5c is connected to the gas-liquid separation tank 3. The pipe 5d is connected to the pipe connection 12b of the separator 12, and the other end of the pipe 5c is connected to the gas-liquid separation tank 3. The pipe 5d is connected to the pipe connection 12b of the separator 12, and the other end of the pipe 5e is connected to the gas-liquid separation tank 3, and the other end of the pipe 5e is connected to the switching valve 7. The pipe 5f is connected to the intake port 2i of the pump 2, and the other end of the pipe 5f is connected to the switching valve 7. One end of the pipe 5g is connected to the exhaust port 2o of the pump 2, and the other end is connected to the switching valve 7. The pipe 5h is connected to the switching valve 7, and one end of the pipe 5h is connected to the atmosphere.

[0028] The pipe 5i is a pipe that connects the pipes 5a and 5b, and has one end connected to the switching valve 6a arranged in the pipe 5a and the other end connected to the switching valve 6c arranged in the pipe 5b. The pipe 5j is a pipe that connects the pipes 5c and 5d, and has one end connected to the switching valve 6b arranged in the pipe 5c and the other end connected to the switching valve 6d arranged in the pipe 5d. In this case, in the fuel cell unit 1 of this example, a "third pipe connecting the exhaust port of the second separator to the gas-liquid separation tank" is configured by the section between the pipe connection part 12b and the switching valve 6d in the pipe 5d, the switching valve 6d, the pipe 5j, the switching valve 6b, and the section between the switching valve 6b and the gas-liquid separation tank 3 in the pipe 5c.

[0029] The pipe 5w is an example of a "first pipe for supplying the water separated in the gas-liquid separation tank to the fuel supply device as a raw material", and has one end connected to the bottom of the gas-liquid separation tank 3 and the other end connected to the hydrogen generation device 20. In this case, the water discharged together with air from the separator 11 and recovered in the gas-liquid separation tank 3 is acidic with a pH of about 2. The water discharged together with hydrogen from the hydrogen generation device 20 and recovered in the gas-liquid separation tank, and the water generated by condensation in the hydrogen flow path 12c are also acidic with a pH of about 4. Therefore, in the fuel cell unit 1 of this example, an ion exchange treatment device (for example, SO4 2- An anion exchange resin filter (not shown) capable of removing sulfuric acid ions (sulfate ions) is provided, and before the water is supplied to the hydrogen generation device 20, it is ion-exchanged in an ion exchange treatment device, thereby preventing deterioration of metal parts and piping within the device and improving the processing efficiency of the electrolysis process in the hydrogen generation device 20.

[0030] The switching valve 6a is disposed in the pipe 5a, and as described later, under the control of the control unit 9, allows / restricts the inflow of air from the pipe 5a to the separator 11 and from the separator 11 to the pipe 5a (passage of air between the portion of the pipe 5a where the switching valve 6a is disposed and the end of the pipe connected to the pipe connection unit 11a), and the inflow of air from the portion of the pipe 5a where the switching valve 6a is disposed to the pipe 5i. The switching valve 6b is disposed in the pipe 5c, and as described later, under the control of the control unit 9, allows / restricts the inflow of air from the separator 11 to the pipe 5c and from the pipe 5c to the separator 11 (passage of air between the end of the pipe 5c where the pipe connection unit 11b is disposed and the portion of the switching valve 6b), and the inflow of air from the pipe 5j to the portion of the pipe 5c where the switching valve 6b is disposed (passage of air between the portion of the pipe 5c where the switching valve 6b is disposed and the end of the pipe connected to the gas-liquid separation tank 3).

[0031] The switching valve 6c is disposed in the pipe 5b, and as described later, under the control of the control unit 9, allows / restricts the inflow of hydrogen gas into the separator 12 via the pipe 5b, the inflow of hydrogen gas from the position of the switching valve 6c in the pipe 5b to the pipe 5i, and the inflow of air from the pipe 5i to the position of the switching valve 6c in the pipe 5b (passage of air between the position of the switching valve 6c in the pipe 5b and the end connected to the pipe connection part 12a). The switching valve 6d is disposed in the pipe 5d, and as described later, under the control of the control unit 9, allows / restricts the inflow of hydrogen gas into the post-treatment device 4 via the pipe 5d (passage of hydrogen gas between the position of the switching valve 6d in the pipe 5d and the end connected to the post-treatment device 4), the inflow of hydrogen gas from the position of the switching valve 6d in the pipe 5d to the pipe 5j, and the inflow of air from the position of the switching valve 6d in the pipe 5d to the pipe 5j.

[0032] In this case, in the fuel cell unit 1 of this example, the above-mentioned switching valves 6a and 6c work together to form a “second valve mechanism.” Also, in the fuel cell unit 1 of this example, the switching valves 6b and 6d work together to form a “third valve mechanism.”

[0033] The switching valve 7 is an example of a "connection switching device that selectively connects either the intake port or the exhaust port of the pump to the gas-liquid separation tank" and is configured to be able to switch between a connection state in which the pipes 5e, 5f communicate with each other and the pipes 5g, 5h communicate with each other as shown in Figures 1 and 3, and a connection state in which the pipes 5e, 5g communicate with each other and the pipes 5f, 5h communicate with each other as shown in Figure 2, under the control of the control unit 9. The on-off valve 8 is an example of a "first valve mechanism" and is disposed in the pipe 5w, and allows / restricts the supply of water from the gas-liquid separation tank 3 to the hydrogen generation device 20 under the control of the control unit 9.

[0034] The control unit 9 performs overall control of the fuel cell unit 1. Specifically, the control unit 9 is an example of a "control unit" and controls the switching valve 7 to selectively connect either the intake port 2i or the exhaust port 2o of the pump 2 to the gas-liquid separation tank 3, and controls the pump 2 to supply air to the fuel cell 10. The control unit 9 also controls the hydrogen generator 20 to generate hydrogen gas and supply it to the fuel cell 10 (separator 12). The control unit 9 also switches the switching valves 6a to 6d and the on-off valve 8 between an open state and a closed state. The operation control of each unit by the control unit 9 will be described in detail later.

[0035] As described above, in this fuel cell unit 1, air (atmospheric air: oxygen) and hydrogen generated in the hydrogen generation device 20 are reacted in the fuel cell 10 to generate electricity. In addition, in the hydrogen generation device 20, hydrogen is generated by electrolysis using, as "raw materials," water generated in the fuel cell 10 (separator 11) during power generation, water generated during hydrogen generation in the hydrogen generation device 20 (water discharged together with hydrogen), and water generated in the hydrogen flow path 12c due to condensation. Therefore, during initial operation immediately after installation of the fuel cell unit 1, or when starting operation after a long period of suspension (when there is not a sufficient amount of water in the gas-liquid separation tank 3), water (raw material) for generating hydrogen required to start power generation is injected into the hydrogen generation device 20.

[0036] In this state, when an instruction to start power generation is given by operating an operating unit not shown (an example of "when generating power in the fuel cell main body"), the control unit 9 transitions the on-off valve 8 to a closed state, as shown in FIG. 1 (an example of control of "controlling the first valve mechanism to transition to a closed state in which the first piping is blocked"). The control unit 9 controls the switching valve 6a to restrict the inflow of air from the location of the switching valve 6a in the pipe 5a to the pipe 5i, controls the switching valve 6b to restrict the inflow of air from the location of the switching valve 6b in the pipe 5c to the pipe 5j, controls the switching valve 6c to restrict the inflow of hydrogen gas from the location of the switching valve 6c in the pipe 5b to the pipe 5i, and controls the switching valve 6d to restrict the inflow of hydrogen gas from the location of the switching valve 6d in the pipe 5d to the pipe 5j (one example of the control of "controlling the second valve mechanism to restrict the inflow of the first gas into the second pipe, and controlling the third valve mechanism to transition to a closed state that blocks the third pipe"). Note that in this figure and in Figures 2 and 3 to be referred to later, the ports that have been transitioned to the closed state in the switching valves 6a and 6d and the on-off valve 8 are illustrated in black, and the ports that have been transitioned to the open state are illustrated in white.

[0037] The control unit 9 also controls the switching valve 7 to connect the intake port 2i (piping 5f) of the pump 2 to the gas-liquid separation tank 3 (piping 5e) and to connect the exhaust port 2o (piping 5g) to the pipe 5h (an example of the control of "controlling the connection switching device to connect the intake port of the pump to the gas-liquid separation tank"). Next, the control unit 9 controls the pump 2 to start pumping air. At this time, air in the air flow path 11c of the fuel cell 10 (separator 11) is sucked from the intake port 2i of the pump 2 via the pipe 5f, the switching valve 7, the pipe 5e, the gas-liquid separation tank 3, and the pipe 5c, so that new air is sucked (supplied) from the pipe connection part 11a into the air flow path 11c via the pipe 5a (an example of the first control mode of "causing the pump to suck the first gas from the first separator via the gas-liquid separation tank to cause new first gas to flow into the first separator").

[0038] Next, the control unit 9 controls the hydrogen generation device 20 to start generating hydrogen. In response to this, the hydrogen generation device 20 electrolyzes water as a raw material to generate hydrogen, and causes the generated hydrogen (hydrogen gas) to flow from the pipe connection part 12a through the pipe 5b into the separator 12. As a result, in the fuel cell 10, air (oxygen) passing through the air flow path 11c of the separator 11 and hydrogen gas (hydrogen) passing through the hydrogen flow path 12c of the separator 12 are reacted through the MEA 13 to generate electricity.

[0039] In this case, as described above, when power generation is performed in the fuel cell 10, water is generated in the air flow path 11c (cathode electrode side of the MEA 13) of the separator 11 by the reaction between oxygen and hydrogen. At this time, the water generated in the air flow path 11c is discharged from the pipe connection part 11b to the pipe 5c together with the air passed through the air flow path 11c and guided to the gas-liquid separation tank 3. As a result, the air from which water droplets (liquid phase moisture) have been separated (water droplets have been removed) in the gas-liquid separation tank 3 is sucked into the pump 2 from the intake port 2i via the pipe 5e, the switching valve 7, and the pipe 5f, exhausted from the exhaust port 2o, and released to the atmosphere via the pipe 5g, the switching valve 7, and the pipe 5h. The water separated from the air is stored in the gas-liquid separation tank 3.

[0040] On the other hand, when a specified amount of water is stored in the gas-liquid separation tank 3 by continuing power generation under the above-mentioned conditions, or when the amount of water usable as a raw material in the hydrogen generation device 20 falls below a specified amount, the control unit 9 continues power generation in the fuel cell 10 while supplying the water in the gas-liquid separation tank 3 to the hydrogen generation device 20 as a raw material for hydrogen production. Note that the above-mentioned condition "when a specified amount of water is stored in the gas-liquid separation tank 3" can be specified as either "when a sufficient amount of water is stored to supply to the hydrogen generation device 20 (when the amount is not so small that it would be necessary to immediately stop the supply even if the supply is started)" or "when there is a risk that the amount that can be stored will be exceeded (when there is a risk that the water in the gas-liquid separation tank 3 will be sucked into the pump 2)."

[0041] Here, when any of the above conditions is satisfied, as shown in FIG. 2, the control unit 9 controls the switching valve 6a to restrict the inflow of air from the position in the pipe 5a where the switching valve 6a is installed to the pipe 5i, controls the switching valve 6b to restrict the inflow of air from the position in the pipe 5c where the switching valve 6b is installed to the pipe 5j, controls the switching valve 6c to restrict the inflow of hydrogen gas from the position in the pipe 5b where the switching valve 6c is installed to the pipe 5i, and controls the switching valve 6d to restrict the inflow of hydrogen gas from the position in the pipe 5d where the switching valve 6d is installed to the pipe 5j (another example of the control of "controlling the second valve mechanism to restrict the inflow of the first gas into the second pipe, and controlling the third valve mechanism to transition to a closed state in which the third pipe is blocked"), and transitions the on-off valve 8 to an open state while the pump 2 and the hydrogen generation device 20 are continuously operated (an example of the control of "controlling the first valve mechanism to transition to an open state in which the first pipe is opened").

[0042] As shown in the figure, the control unit 9 controls the switching valve 7 to connect the exhaust port 2o (piping 5g) of the pump 2 to the gas-liquid separation tank 3 (piping 5e) and connects the intake port 2i (piping 5f) to the pipe 5h (one example of the control of "controlling the connection switching device to connect the exhaust port of the pump to the gas-liquid separation tank"). At this time, the air sucked into the pump 2 from the intake port 2i via the pipe 5h, the switching valve 7, and the pipe 5f is made to flow from the pipe connection part 11b into the fuel cell 10 (separator 11) via the pipe 5g, the switching valve 7, the pipe 5e, the gas-liquid separation tank 3, and the pipe 5c, and is exhausted from the pipe connection part 11a after passing through the air flow path 11c and is released to the atmosphere via the pipe 5a. As a result, power generation continues by the reaction between the hydrogen gas (hydrogen) supplied from the hydrogen generation device 20 and passed through the hydrogen flow path 12c and the air (oxygen) passed through the air flow path 11c in the opposite direction to that in the above-mentioned "first control mode".

[0043] In addition, in the state where the air pressure-fed by the pump 2 is supplied to the fuel cell 10 (separator 11) via the gas-liquid separation tank 3 as described above, the inside of the gas-liquid separation tank 3 is in a pressurized state. At this time, in the fuel cell unit 1 of this example, the hydrogen generation device 20 is connected via the pipe 5w to the vicinity of the bottom of the gas-liquid separation tank 3 (the portion where the separated water is collected). Therefore, the water separated from the air and stored in the gas-liquid separation tank 3 is discharged from the gas-liquid separation tank 3 to the pipe 5w by the force of the air pressure-fed into the gas-liquid separation tank 3, and is pressure-fed to the hydrogen generation device 20 without using a power source such as a liquid feed pump (an example of the "second control mode for pressure-fed the water separated in the gas-liquid separation tank from the gas-liquid separation tank to the fuel supply device via the first pipe").

[0044] As a result, the water discharged from separator 11 together with air and stored in gas-liquid separation tank 3 is supplied to hydrogen generation device 20 as a raw material for generating hydrogen. Furthermore, by continuing the supply of water to hydrogen generation device 20, when the amount of water stored in gas-liquid separation tank 3 falls below a specified amount, control unit 9 controls each component in the above-mentioned "first control mode". As a result, the water generated in separator 11 is separated and stored in gas-liquid separation tank 3.

[0045] On the other hand, when hydrogen gas is supplied from the hydrogen generating device 20 to the fuel cell 10 (separator 12) for power generation, as described above, the moisture in the hydrogen gas may condense in the hydrogen flow path 12c due to heat exchange with the fuel cell 10 (separator 12), air passing through the air flow path 11c, and a refrigerant passing through the cooling separator, resulting in water droplets in the hydrogen flow path 12c. Also, a small amount of water (water that has not been electrolyzed) may be discharged from the hydrogen generating device 20 together with the hydrogen gas, and this water may flow into the separator 12 together with the hydrogen gas. In this case, the amount of water generated in the hydrogen flow path 12c and the amount of water flowing into the hydrogen flow path 12c via the pipe 5b is less than the amount of water generated in the air flow path 11c during power generation, but the water droplets (liquid-phase moisture) present in the hydrogen flow path 12c may act as a resistance to the passage of hydrogen gas, making it difficult to pass a sufficient amount of hydrogen to react with air (oxygen).

[0046] Therefore, in the fuel cell unit 1 of this embodiment, as an example, a configuration is adopted in which, when an instruction to end power generation is given (an example of "when a predefined condition is satisfied in a state in which power generation is not being performed in the fuel cell main body"), water in the hydrogen flow path 12c is discharged from the separator 12 and recovered in the gas-liquid separation tank 3. Specifically, the control unit 9 stops the hydrogen generation device 20 while continuing to operate the pump 2.

[0047] 3, the control unit 9 shifts the on-off valve 8 to a closed state (one example of the control of "controlling the first valve mechanism to shift to the closed state"). The control unit 9 also controls the switching valve 6a to restrict the inflow of air from the pipe 5a to the separator 11 (passage of air between the position of the switching valve 6a in the pipe 5a and the end connected to the pipe connection part 11a), while allowing the inflow of air from the position of the switching valve 6a in the pipe 5a to the pipe 5i, and controls the switching valve 6c to allow the inflow of air from the pipe 5i to the position of the switching valve 6c in the pipe 5b (passage of air between the position of the switching valve 6c in the pipe 5b and the end connected to the pipe connection part 12a).

[0048] As shown in the figure, the control unit 9 controls the switching valve 6d to restrict the inflow of air from the pipe 5d to the post-treatment device 4 (the passage of air between the location of the switching valve 6d in the pipe 5d and the connection end of the post-treatment device 4), while allowing the inflow of air from the location of the switching valve 6d in the pipe 5d to the pipe 5j, and controls the switching valve 6b to allow the inflow of air from the pipe 5j to the location of the switching valve 6b in the pipe 5c (the passage of air between the location of the switching valve 6b in the pipe 5c and the connection end of the gas-liquid separation tank 3) (an example of control of "controlling the second valve mechanism to allow the inflow of the first gas into the second pipe, and controlling the third valve mechanism to transition to an open state in which the third pipe is opened").

[0049] In addition, the control unit 9 controls the switching valve 7 to connect the intake port 2i (piping 5f) of the pump 2 to the gas-liquid separation tank 3 (piping 5e) and to connect the exhaust port 2o (piping 5g) to the pipe 5h (an example of the control of "controlling the connection switching device to connect the intake port of the pump to the gas-liquid separation tank").

[0050] At this time, gas and water droplets (gas containing a small amount of unreacted hydrogen immediately after switching to operation in this control mode) in hydrogen flow path 12c are sucked in via pipe 5f, switching valve 7, pipe 5e, gas-liquid separation tank 3, and pipes 5c, 5j, and 5d, and as this gas passes through gas-liquid separation tank 3, water droplets (liquid phase moisture) are separated (water droplets are removed), and then the gas is sucked into pump 2 from intake port 2i via pipe 5e, switching valve 7, and pipe 5f, and is released into the atmosphere via pipe 5g, switching valve 7, and pipe 5h (an example of "a third control mode in which the water contained in the first gas exhausted from the second separator is separated and recovered in the gas-liquid separation tank by causing the pump to suck in the first gas from the second separator via the gas-liquid separation tank and the third pipe").

[0051] Furthermore, air is sucked into hydrogen flow passage 12c by pump 2, and air is sucked into hydrogen flow passage 12c from pipe connection 12a via pipes 5b, 5i, and 5a, and water (liquid-phase moisture) in hydrogen flow passage 12c together with the air is discharged from separator 12 (pipe connection 12b) and separated from the air in gas-liquid separation tank 3. Therefore, by operating each part in a state controlled by this "third control mode", no water droplets are present in hydrogen flow passage 12c, and water that can be used as a raw material for generating hydrogen in hydrogen generation device 20 is stored in gas-liquid separation tank 3. As a result, when power is next generated (when hydrogen is generated in hydrogen generation device 20), water as a raw material can be supplied from gas-liquid separation tank 3 to hydrogen generation device 20 by controlling each part in the above-mentioned "second control mode".

[0052] In this manner, in the fuel cell unit 1, when generating electricity in the fuel cell 10, the control unit 9 is configured to be able to control the pump 2, the switching valve 7 and the on-off valve 8 in either of a "first control mode" in which the control unit 9 controls the on-off valve 8 to transition to a closed state in which the piping 5w is blocked, and controls the switching valve 7 to operate the pump 2 in a state in which the intake port 2i of the pump 2 is connected to the gas-liquid separation tank 3, thereby causing the pump 2 to suck in the first gas (in this example, air) from the separator 11 through the gas-liquid separation tank 3, thereby causing new first gas to flow into the separator 11; and a "second control mode" in which the control unit 9 controls the on-off valve 8 to transition to an open state in which the piping 5w is open, and controls the switching valve 7 to operate the pump 2 in a state in which the exhaust port 2o of the pump 2 is connected to the gas-liquid separation tank 3, thereby pressure-feeding the first gas from the pump 2 to the separator 11 through the gas-liquid separation tank 3, and pressure-feeding the water separated in the gas-liquid separation tank 3 from the gas-liquid separation tank 3 to the hydrogen generation device 20 via the piping 5w.

[0053] Therefore, according to this fuel cell unit 1, unlike a configuration in which water (pure water) used as a raw material in an electrolysis device for generating hydrogen is generated by an electric regenerative type pure water generator, by controlling each part in the "first control mode", water discharged from the fuel cell 10 (separator 11) during power generation is separated and collected in the gas-liquid separation tank 3, and this water can be used as a raw material for generating hydrogen in the hydrogen generation device 20. Since no electricity is required to generate the raw water, the cost of generating hydrogen can be sufficiently reduced. In addition, by controlling each part in the "second control mode", it is possible to pressure-feed the water in the gas-liquid separation tank 3 from the gas-liquid separation tank 3 to the hydrogen generation device 20 while continuing power generation, without transporting the water collected in the gas-liquid separation tank 3 using a transport container or the like to inject it into the hydrogen generation device 20, or without providing a liquid feed pump or the like for pressure-feeding water from the gas-liquid separation tank 3 to the hydrogen generation device 20, and thus the cost of generating hydrogen can be further reduced. As a result, the cost of generating electricity using hydrogen generated in the hydrogen generation device 20 can be sufficiently reduced.

[0054] In addition, in this fuel cell unit 1, when the control unit 9 performs control in the "first control mode" and the "second control mode", it controls the switching valves 6a and 6c to restrict the inflow of the first gas into the pipe 5b, and controls the switching valves 6b and 6d to transition to a closed state in which the pipes 5d, 5j, and 5c are blocked, and when a predefined condition is satisfied in a state in which the fuel cell 10 is not generating power (for example, when an instruction to end power generation is received), it controls the on-off valve 8 to transition to a closed state and controls the switching valves 6a and 6c to allow the inflow of the first gas into the pipe 5b, The pump 2, the switching valve 7, the on-off valve 8 and the switching valves 6a to 6d are controlled in a "third control mode" in which the switching valves 6b, 6d are controlled to transition to an open state in which the pipes 5d, 5j, 5c are opened, and the switching valve 7 is controlled to operate the pump 2 in a state in which the intake port 2i of the pump 2 is connected to the gas-liquid separation tank 3, thereby causing the pump 2 to suck in the first gas from the separator 12 via the gas-liquid separation tank 3 and the pipes 5d, 5j, 5c, and thereby separating and recovering water contained in the first gas exhausted from the separator 12 in the gas-liquid separation tank 3.

[0055] Therefore, according to this fuel cell unit 1, not only can a sufficient amount of water be secured for use as a raw material in the hydrogen generation device 20, but it is also possible to preferably avoid a state in which a large amount of water droplets (liquid phase water) discharged from the hydrogen generation device 20 along with the hydrogen gas produced in the hydrogen generation device 20, or water droplets (liquid phase water) caused by condensation are present in the separator 12 (hydrogen flow path 12c), which would result in an excessively large resistance to the passage of hydrogen gas supplied during power generation.As a result, power generation can be preferably performed in the fuel cell 10.

[0056] The configuration of the "fuel cell unit" is not limited to the example of the configuration of the fuel cell unit 1 described above.

[0057] For example, the configuration has been described as an example in which water discharged together with hydrogen gas from the hydrogen generation device 20 (water separated from hydrogen gas in the gas-liquid separation tank) or water condensed in the hydrogen flow path 12c can be used as a "raw material". However, when the amount of water discharged from the hydrogen generation device 20 or water condensed in the hydrogen flow path 12c is extremely small, a configuration can be adopted in which this water is not used as a "raw material". [Explanation of symbols]

[0058] 1 Fuel Cell Unit 2. Pump 2i Air Intake 2o Exhaust port 3 Gas-liquid separation tank 4 Aftertreatment Device 5a~5j,5w piping 6a~6d Switching valve 7. Switching valve 8. On-off valve 9. Control Unit 10 Fuel Cell 11,12 Separator 11a, 11b, 12a, 12b Piping connection parts 11c Air passage 12c Hydrogen flow path 13 MEA 20 Hydrogen Generator

Claims

1. a fuel cell main body, which is constructed by stacking and integrating a plurality of flat plate-shaped laminated objects including at least a first separator through which a first gas containing an oxidant is passed, a second separator through which a second gas containing hydrogen is passed, and a membrane electrode assembly disposed between the first separator and the second separator, and which is configured to generate electricity by reacting the first gas with the second gas via the membrane electrode assembly; a pump that supplies the first gas to the first separator; a fuel cell unit including: a fuel cell supply device that electrolyzes raw water to generate the hydrogen and generate the second gas, and that supplies the generated second gas to the second separator, a gas-liquid separation tank disposed between the first separator and the pump for separating and recovering water contained in the exhaust gas discharged from the first separator; a connection switching device that selectively connects either an intake port or an exhaust port of the pump to the gas-liquid separation tank; a first pipe for supplying the water separated in the gas-liquid separation tank to the fuel supply device as the raw material; a first valve mechanism disposed in the first pipe; a control unit that controls the pump, the connection switching device, and the first valve mechanism, When generating power in the fuel cell main body, the control unit a first control mode in which the first valve mechanism is controlled to transition to a closed state in which the first pipe is blocked, and the connection switching device is controlled to operate the pump in a state in which the intake port of the pump is connected to the gas-liquid separation tank, thereby causing the pump to suck the first gas from the first separator through the gas-liquid separation tank, thereby causing new first gas to flow into the first separator; a second control mode in which the first gas is pressure-fed from the pump to the first separator via the gas-liquid separation tank and water separated in the gas-liquid separation tank is pressure-fed from the pump to the first separator via the gas-liquid separation tank and water separated in the gas-liquid separation tank is pressure-fed from the gas-liquid separation tank to the fuel supply device via the first piping by controlling the first valve mechanism to transition to an open state in which the first piping is opened, and by controlling the connection switching device to operate the pump in a state in which the exhaust port of the pump is connected to the gas-liquid separation tank.

2. a second pipe for supplying the second gas from the fuel supply device to the second separator; a third pipe connecting an exhaust port of the second separator to the gas-liquid separation tank; a second valve mechanism that restricts / allows an inflow of the first gas into the second pipe; a third valve mechanism disposed in the third pipe; When performing control in the first control mode and the second control mode, the control unit controls the second valve mechanism to restrict the inflow of the first gas into the second pipe, and controls the third valve mechanism to transition to a closed state in which the third pipe is blocked; 2. The fuel cell unit according to claim 1, wherein the pump, the connection switching device, the first valve mechanism, the second valve mechanism and the third valve mechanism are controllable in a third control mode in which, when predetermined conditions are satisfied in a state in which power generation is not being performed in the fuel cell main body, the first valve mechanism is controlled to transition to the closed state, the second valve mechanism is controlled to allow the first gas to flow into the second piping, and the third valve mechanism is controlled to transition to an open state in which the third piping is opened, and the connection switching device is controlled to operate the pump in a state in which the intake port of the pump is connected to the gas-liquid separation tank, thereby causing the pump to suck in the first gas from the second separator via the gas-liquid separation tank and the third piping, thereby separating and recovering water contained in the first gas exhausted from the second separator in the gas-liquid separation tank.

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