Power generating system

Abstract

To provide a power generating system that can sufficiently improve power generation efficiency without requiring complicated control.SOLUTION: A power generating system 1 includes a fuel cell 10 in which a plurality of flat plate-shaped laminated materials including at least a separator 11 through which air passes, a separator 12 through which hydrogen gas G passes, and an MEA 13 disposed between the separators 11, 12 are stacked and integrated together, and configured to generate electricity by reacting air with hydrogen gas G via the MEA 13. The power generating system 1 includes a humidifier 4 having a water tank 21 through which hydrogen gas G to be supplied to the separator 12 can pass, and humidifying the hydrogen gas G that is passed through the water tank 21. The humidifier 4 includes a "first heat exchange section" that heats water W in the water tank 21 by heat exchange with air discharged from the separator 11.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power generation system configured to be capable of generating power by a reaction between a first gas containing an oxidant and a second gas containing hydrogen. [Background technology]

[0002] When generating electricity using a fuel cell, it is necessary to supply hydrogen gas or the like with sufficient humidity to the fuel cell in order to avoid a decrease in power generation efficiency and damage to the membrane electrode assembly due to excessive drying of the membrane electrode assembly. For this reason, when using low-humidity hydrogen gas, a configuration is widely adopted in which the hydrogen gas is humidified before being supplied to the fuel cell.

[0003] For example, the following patent document discloses an invention for a fuel cell evaluation test device (hereinafter simply referred to as "test device") that performs an evaluation test of the performance of a fuel cell by adjusting supply conditions such as the temperature and humidity of gases ("gas containing oxygen (positive electrode side gas: cathode gas)" and "gas containing hydrogen (negative electrode side gas: anode gas)": hereinafter also referred to as "air" and "hydrogen gas") supplied from a gas supply device to a fuel cell. In this test device, the gas supply device is equipped with a humidification means that adjusts (humidifies) the humidity of air or hydrogen gas, a flow rate adjustment means that adjusts the flow rate of gas that passes through the humidification means (gas to be humidified), and a flow rate adjustment means that adjusts the flow rate of gas that does not pass through the humidification means (gas not to be humidified), and is configured to be able to adjust the humidity of the gas supplied to the fuel cell by adjusting the mixture ratio of gas humidified by the humidification means and gas that is not humidified (adjusting the amount of gas passing by both flow rate adjustment means).

[0004] In this case, the humidifying means includes a sealed storage tank for storing stored water (e.g., pure water) and a heater (electric heater: water temperature adjusting means) for heating the stored water in the storage tank, and is configured to discharge gas from a gas inlet provided at the bottom of the storage tank into the stored water to humidify (bubble) the gas rising in the stored water and discharge it from a gas outlet provided at the top of the storage tank. As a result, in this test device, gas sufficiently humidified by the humidifying means and gas not humidified by the humidifying means are mixed in any ratio and supplied to the fuel cell, making it possible to reproduce power generation under conditions in which the membrane electrode assembly is not excessively dried, or power generation under conditions in which the membrane electrode assembly is excessively dried or excessively wet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-210205 A (Page 4-21, Figure 1-4D) Summary of the Invention [Problem to be solved by the invention]

[0006] However, the configuration of the test device disclosed in the above-mentioned patent document has the following problems to be solved.

[0007] Specifically, the test device disclosed in the above patent document employs a configuration in which a portion of the gas supplied to the fuel cell is humidified when it is caused to float in the water stored in the humidifying means (storage tank). In this case, the humidifying means of this test device employs a configuration in which the temperature and humidity of the gas are adjusted by heating the water stored in the storage tank with an electric heater. For this reason, when the configuration of the test device disclosed in this patent document is adopted in an actual power generation system using a fuel cell, in the power generation system for obtaining electric power, power is consumed by the electric heater to heat the water (stored water in the above patent document) for humidifying hydrogen gas, etc., which leads to a decrease in the power generation efficiency of the power generation system as a whole.

[0008] In addition, when generating electricity using a fuel cell, the temperature of the power generating cell changes successively depending on the time elapsed since the start of power generation and changes in the power generation environment, such as the amount of power generated. In this case, when gas adjusted to a humidity suitable for power generation in a certain power generation environment is supplied to the power generating cell, if the temperature of the power generating cell rises more than expected, the temperature of the supplied gas rises and the relative humidity falls, and if the temperature of the power generating cell falls more than expected, the temperature of the supplied gas falls and the relative humidity rises or some of the moisture changes into a liquid phase. As a result, in either case, there is a risk of a decrease in power generation efficiency, and to avoid this, complicated controls are required, such as changing the amount of electricity supplied to the electric heater depending on the temperature of the power generating cell, adjusting the water temperature in the humidifying water tank (the temperature of the stored water in the storage tank in the configuration of the above patent document), and adjusting the mixture ratio.

[0009] The present invention has been made in consideration of the above problems to be solved, and has as its main object to provide a power generation system that can sufficiently improve power generation efficiency without requiring complicated control. [Means for solving the problem]

[0010] In order to achieve the above object, the power generation system described in claim 1 is a power generation system including a power generation cell in which a first gas containing an oxidant is passed, a second separator through which a second gas containing hydrogen is passed, and a plurality of flat plate-shaped laminated objects including at least the membrane electrode assembly disposed between the first separator and the second separator are stacked and integrated, and configured to generate power by reacting the first gas with the second gas via the membrane electrode assembly, the power generation system further including a humidifier having a water tank through which the second gas to be supplied to the second separator can pass and humidifying the second gas passed through the water tank, and the humidifier includes a first heat exchanger that heats water in the water tank by heat exchange with the first gas discharged from the first separator.

[0011] The power generation system of claim 2 is the power generation system of claim 1, further comprising a first suction pump that introduces new first gas into the first separator by sucking the first gas from the first separator, and the humidifier comprises a second heat exchange unit that heats the water in the water tank by heat exchange with the first gas discharged from the first suction pump.

[0012] The power generation system of claim 3 is the power generation system of claim 1, further comprising a third heat exchange section that heats the second gas to be introduced into the humidifier by heat exchange with the first gas discharged from the first separator.

[0013] The power generation system of claim 4 is the power generation system of claim 2, further comprising a fourth heat exchange unit that heats the second gas to be introduced into the humidifier by heat exchange with the first gas discharged from the first suction pump.

[0014] The power generation system of claim 5 is the power generation system of claim 1, further comprising a fifth heat exchange section that heats the second gas discharged from the humidifier by heat exchange with the first gas discharged from the first separator.

[0015] The power generation system of claim 6 is the power generation system of claim 2, further comprising a sixth heat exchanger that heats the second gas discharged from the humidifier by heat exchange with the first gas discharged from the first suction pump.

[0016] The power generation system described in claim 7 is a power generation system including a power generation cell 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 plurality of flat plate-like laminated objects including at least the membrane electrode assembly disposed between the first separator and the second separator, which are stacked and integrated, and configured to generate power by reacting the first gas with the second gas via the membrane electrode assembly, the power generation system further including a humidifier having a water tank through which the second gas to be supplied to the second separator can pass and humidifying the second gas passed through the water tank; The power generation cell includes a third separator as the laminated material that is formed to allow a third gas to pass through and is configured to cool the power generation cell by heat exchange with the third gas, and the humidifier includes a heat exchange section A that heats the water in the water tank by heat exchange with the third gas discharged from the third separator.

[0017] The power generation system of claim 8 is the power generation system of claim 7, further comprising a second suction pump that introduces new third gas into the third separator by sucking the third gas from the third separator, and the humidifier comprises a heat exchange unit B that heats the water in the water tank by heat exchange with the third gas discharged from the second suction pump.

[0018] The power generation system of claim 9 is the power generation system of claim 7, further comprising a heat exchange section C that heats the second gas to be introduced into the humidifier by heat exchange with the third gas discharged from the third separator.

[0019] The power generation system of claim 10 is the power generation system of claim 8, further comprising a heat exchange section D that heats the second gas to be introduced into the humidifier by heat exchange with the third gas discharged from the second suction pump.

[0020] The power generation system of claim 11 is the power generation system of claim 7, further comprising a heat exchange section E that heats the second gas discharged from the humidifier by heat exchange with the third gas discharged from the third separator.

[0021] The power generation system of claim 12 is the power generation system of claim 8, further comprising a heat exchange section F that heats the second gas discharged from the humidifier by heat exchange with the third gas discharged from the second suction pump. Effect of the Invention

[0022] The power generation system according to claim 1 includes a water tank through which the second gas to be supplied to the second separator can pass, and a humidifier that humidifies the second gas that is passed through the water tank, and the humidifier includes a first heat exchanger that heats the water in the water tank by heat exchange with the first gas discharged from the first separator. Therefore, according to the power generation system according to claim 1, by utilizing the heat of the first gas (the first gas discharged from the first separator) whose temperature has increased due to heat generated by the power generation cell during power generation, the water in the water tank can be heated to a state that is easy to vaporize without consuming power to humidify the second gas, unlike a configuration in which the water for humidification is heated by an electric heater, and the second gas that is made to float in the water can be suitably humidified, thereby sufficiently improving the power generation efficiency in the power generation system. Furthermore, the temperature of the power generating cell rises in response to an increase in the amount of the second gas supplied to the power generating cell, i.e., an increase in the amount of power generated by the power generating system, and this causes the temperature of the first gas discharged from the first separator to rise, so that by heating water through heat exchange with this first gas, the water can be heated more appropriately when the amount of the second gas to be humidified by the humidifier is greater. This allows the second gas to be humidified more appropriately without performing complicated controls.

[0023] The power generation system according to claim 2 includes a first suction pump that draws the first gas from the first separator to introduce new first gas into the first separator, and the humidifier includes a second heat exchanger that heats the water in the water tank by heat exchange with the first gas discharged from the first suction pump. Therefore, the power generation system according to claim 2 uses not only the heat of the first gas whose temperature has increased due to heat generation from the power generation cell, but also the heat of the first gas (the first gas discharged from the first suction pump) whose temperature has increased due to compression by the first suction pump and mechanical heat generation by the first suction pump, thereby making it possible to heat the water in the water tank more effectively without consuming power for humidifying the second gas. Furthermore, as the amount of the second gas supplied to the power generation cell increases, i.e., as the amount of power generation by the power generation system increases, the amount of the first gas sucked in (compressed) by the first suction pump also increases, and as a result, the temperature of the first gas discharged from the first suction pump increases.By heating water through heat exchange with this first gas, the water can be heated more effectively when the amount of the second gas to be humidified by the humidifier is greater.

[0024] The power generation system according to claim 3 includes a third heat exchanger that heats the second gas introduced into the humidifier by heat exchange with the first gas discharged from the first separator. Therefore, according to the power generation system according to claim 3, the relative humidity of the second gas introduced into the humidifier is reduced by utilizing the heat of the first gas (the first gas discharged from the first separator) whose temperature has increased due to heat generated by the power generation cell during power generation, and thus the hygroscopicity in the humidifier is sufficiently increased to suitably humidify the gas. As a result, even if the amount of water stored in the humidifier (water tank) is small, the second gas can be suitably humidified to suitably prevent the membrane electrode assembly in the power generation cell from drying up, and the amount of water stored can be small, and the amount of heat consumed to heat the water (the amount of heat exchange between the first gas discharged from the first separator and the water) can be small, and thus a situation in which the amount of heat required to suitably humidify the second gas is insufficient can be suitably avoided.

[0025] The power generation system according to claim 4 includes a fourth heat exchanger that heats the second gas to be introduced into the humidifier by heat exchange with the first gas discharged from the first suction pump. Therefore, the power generation system according to claim 4 can sufficiently reduce the relative humidity of the second gas to be introduced into the humidifier by utilizing not only the heat of the first gas whose temperature has increased due to heat generation from the power generation cell, but also the heat of the first gas (the first gas discharged from the first suction pump) whose temperature has increased due to compression by the first suction pump and mechanical heat generation by the first suction pump. This can reliably avoid a situation in which the amount of heat required to suitably humidify the second gas is insufficient.

[0026] The power generation system according to claim 5 further includes a fifth heat exchanger that heats the second gas discharged from the humidifier by heat exchange with the first gas discharged from the first separator. Therefore, the power generation system according to claim 5 can reduce the relative humidity of the second gas introduced into the second separator by utilizing the heat of the first gas (the first gas discharged from the first separator) whose temperature has increased due to heat generated by the power generation cell during power generation, thereby making it possible to suitably avoid condensation in the hydrogen flow path.

[0027] The power generation system according to claim 6 includes a sixth heat exchanger that heats the second gas discharged from the humidifier by heat exchange with the first gas discharged from the first suction pump. Therefore, the power generation system according to claim 6 uses not only the heat of the first gas whose temperature has increased due to heat generation from the power generation cell, but also the heat of the first gas (the first gas discharged from the first suction pump) whose temperature has increased due to compression by the first suction pump and mechanical heat generation by the first suction pump to reduce the relative humidity of the second gas to be introduced into the second separator, thereby making it possible to preferably avoid a situation in which condensation occurs in the hydrogen flow path.

[0028] The power generation system according to claim 7 includes a water tank through which the second gas to be supplied to the second separator can pass, and a humidifier that humidifies the second gas that is passed through the water tank, and the humidifier includes a heat exchanger A that heats the water in the water tank by heat exchange with the third gas discharged from the third separator. Therefore, according to the power generation system according to claim 7, by utilizing the heat of the third gas (the third gas discharged from the third separator) whose temperature has increased due to heat generated by the power generation cell during power generation, the water in the water tank can be heated to a state where it is easily vaporized without consuming power to humidify the second gas, unlike a configuration in which the water for humidification is heated by an electric heater, and the second gas that is made to float in the water can be suitably humidified, thereby sufficiently improving the power generation efficiency in the power generation system. Furthermore, the temperature of the power generating cell rises in response to an increase in the amount of the second gas supplied to the power generating cell, i.e., an increase in the amount of power generated by the power generating system, and this causes the temperature of the third gas discharged from the third separator to rise, so that by heating water through heat exchange with this third gas, the water can be heated more appropriately when the amount of the second gas to be humidified by the humidifier is greater. This makes it possible to appropriately humidify the second gas without performing complicated controls.

[0029] The power generation system according to claim 8 includes a second suction pump that introduces new third gas into the third separator by sucking the third gas from the third separator, and the humidifier includes a heat exchanger B that heats the water in the water tank by heat exchange with the third gas discharged from the second suction pump. Therefore, according to the power generation system according to claim 8, the water in the water tank can be heated more suitably without consuming power for humidifying the second gas by utilizing not only the heat of the third gas whose temperature has increased due to heat generation from the power generation cell, but also the heat of the third gas (the third gas discharged from the second suction pump) whose temperature has increased due to compression by the second suction pump and mechanical heat generation by the second suction pump. Furthermore, as the amount of the second gas supplied to the power generation cell increases, i.e., as the amount of power generation by the power generation system increases, the amount of the third gas sucked in (compressed) by the second suction pump also increases, and as a result, the temperature of the third gas discharged from the second suction pump increases.By heating water through heat exchange with this third gas, the water can be heated more effectively when the amount of the second gas to be humidified by the humidifier is greater.

[0030] The power generation system according to claim 9 includes a heat exchanger C for heating the second gas introduced into the humidifier by heat exchange with the third gas discharged from the third separator. Therefore, according to the power generation system according to claim 9, the relative humidity of the second gas introduced into the humidifier is reduced by utilizing the heat of the third gas (the third gas discharged from the third separator) whose temperature has increased due to heat generated by the power generation cell during power generation, and thus the hygroscopicity in the humidifier is sufficiently increased to suitably humidify the second gas. As a result, even if the amount of water stored in the humidifier (water tank) is small, the second gas can be suitably humidified to suitably prevent the membrane electrode assembly in the power generation cell from drying up, and the amount of water stored can be small, and the amount of heat consumed to heat the water (the amount of heat exchange between the third gas discharged from the third separator and the water) can be small, and thus a situation in which the amount of heat required to suitably humidify the second gas is insufficient can be suitably avoided.

[0031] The power generation system according to claim 10 includes a heat exchanger D that heats the second gas to be introduced into the humidifier by heat exchange with the third gas discharged from the second suction pump. Therefore, the power generation system according to claim 10 can sufficiently reduce the relative humidity of the second gas to be introduced into the humidifier by utilizing not only the heat of the third gas whose temperature has increased due to heat generation from the power generation cell, but also the heat of the third gas (the third gas discharged from the second suction pump) whose temperature has increased due to compression by the second suction pump and mechanical heat generation by the second suction pump. This can reliably avoid a situation in which the amount of heat required to suitably humidify the second gas is insufficient.

[0032] The power generation system according to claim 11 includes a heat exchanger E that heats the second gas discharged from the humidifier by heat exchange with the third gas discharged from the third separator. Therefore, the power generation system according to claim 11 uses the heat of the third gas (the third gas discharged from the third separator) whose temperature has increased due to heat generated by the power generation cell during power generation to reduce the relative humidity of the second gas introduced into the second separator, thereby making it possible to preferably avoid a situation in which condensation occurs in the hydrogen flow path.

[0033] The power generation system according to claim 12 includes a heat exchanger F that heats the second gas discharged from the humidifier by heat exchange with the third gas discharged from the second suction pump. Therefore, according to the power generation system according to claim 12, the relative humidity of the second gas introduced into the second separator can be reduced by utilizing not only the heat of the third gas whose temperature has increased due to heat generation from the power generation cell, but also the heat of the third gas (the third gas discharged from the second suction pump) whose temperature has increased due to compression by the second suction pump and mechanical heat generation by the second suction pump, thereby making it possible to suitably avoid a situation in which condensation occurs in the hydrogen flow path. [Brief description of the drawings]

[0034] [Figure 1] 1 is a configuration diagram showing a configuration of a power generation system 1. FIG. [Diagram 2] FIG. 2 is an explanatory diagram for explaining the configuration of the humidifier 4. [Diagram 3] FIG. 2 is an explanatory diagram for explaining the configuration of a heating unit 5a. [Figure 4] FIG. 4 is an explanatory diagram for explaining the configuration of a heating unit 5b. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Hereinafter, an embodiment of a power generation system will be described with reference to the accompanying drawings.

[0036] The power generation system 1 shown in FIG. 1 is an example of a "power generation system" 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 G, which is an example of a "second gas containing hydrogen"). In this case, the power generation system 1 of this example is configured to generate electricity using, as the "second gas," hydrogen gas G supplied from a hydrogen gas supply source X, which is configured, for example, by a hydrogen generation device (not shown) installed together with the power generation system 1 at the installation site of the power generation system 1, hydrogen gas G generated by the hydrogen generation device, or a gas tank (not shown) capable of storing hydrogen gas G generated at a different location and transported to the installation site of the power generation system 1.

[0037] This power generation system 1 includes a pump 2, a gas-liquid separation tank 3, a humidifier 4, heating sections 5a, 5b, control valves 6a-6d, 7a-7d, 8a, 8b, a control section 9, a fuel cell 10, and pipes Pa1-Pa5, Pb0-Pb4, Pc1-Pc4, Pd0-Pd4, Pe1-Pe3, Pg1-Pg3, Pw1, and Pw2.

[0038] The fuel cell 10 is an example of a "power generation cell configured to generate power by reacting a first gas with a second gas," and includes a power generation stack configured with a separator 11 (an example of a "first separator") through which air (first gas) passes, a separator 12 (an example of a "second separator") through which hydrogen gas G (second gas) passes, and an MEA 13 (an example of a "membrane electrode assembly") sandwiched between the separators 11 and 12, a separator 14 (an example of a "third separator") through which a "third gas" for cooling (for example, air: atmospheric air) passes, and end plates (not shown) disposed at both ends in the stacking direction of each stack. In this example, the plates such as the separators 11, 12, 14, the MEA 13, and the end plates correspond to "multiple flat plate-shaped stacked objects," and the fuel cell 10 is configured by stacking and integrating these.

[0039] In this case, the separator 11 is formed with a groove (not shown) for passing air, and a pipe Pa1 is connected to the air inlet, and the gas-liquid separation tank 3 is connected to the air outlet via a pipe Pa2. The separator 12 is formed with a groove (not shown) for passing hydrogen gas G, and a humidifier 4 is connected to the hydrogen gas G inlet via a pipe Pg2, and a pipe Pg3 is connected to the hydrogen gas G outlet. A post-treatment device (not shown) is connected downstream of the pipe Pg3 to perform a process required in the use environment of the power generation system 1 on the hydrogen gas G (gas containing unreacted hydrogen that did not react with air during power generation) discharged from the separator 12. The MEA 13 is configured to include an electrolyte membrane, a catalyst layer, a gas diffusion layer, and the like.

[0040] In this fuel cell 10, separators 11, 12 are stacked with MEA 13 sandwiched between them, so that air flow path 11a is formed by the groove of separator 11 and one surface of MEA 13, and hydrogen flow path 12a is formed by the groove of separator 12 and the other surface of MEA 13. Separator 14 is formed with air flow path 14a (pores) for passing cooling air, with pipe Pa4 connected to the air inlet and pipe Pb0 (described below) connected to the air outlet via pipe Pa5, so that separators 11, 12, etc. can be cooled by heat exchange with air passed through air flow path 14a. Note that an actual fuel cell 10 is configured to include multiple of the above-mentioned power generation stacks (separators 11, 12 and MEA 13) and separator 14 depending on the power generation capacity required for the power generation system 1, but in order to make it easier to understand the configuration and operation of the power generation system 1, an example is shown in which one separator 14 is arranged between two power generation stacks.

[0041] The pump 2 corresponds to a "first suction pump that introduces a new first gas into the first separator by sucking a first gas from the first separator" and a "second suction pump that introduces a new third gas into the third separator by sucking a third gas from the third separator" (an example of a configuration in which one pump serves as both the "first pump" and the "second pump"). As will be described later, the pump 2 introduces new air into the separators 11, 14 by sucking air from the separators 11, 14 under the control of the control unit 9. In this case, when the power generation system 1 generates power, the temperature of the fuel cell 10 rises, and therefore the temperature of the air discharged from the separators 11, 14 (sucked from the fuel cell 10 by the pump 2) rises due to heat exchange with the separators 11, 14. Furthermore, while the pump 2 is operating, the temperature of the exhaust air (air drawn in from the fuel cell 10 and discharged from the pump 2) increases due to compression by the pump 2 and mechanical heat generation by the pump 2. Therefore, in the power generation system 1 of this example, a configuration is adopted in which the heat of the air is utilized to heat the water W and hydrogen gas G in the humidifier 4, as will be described later.

[0042] The gas-liquid separation tank 3 is configured to separate the exhaust gas (a mixture of air and water) discharged from the separator 11 and introduced through the pipe Pa2 into air and water. In this case, when generating electricity in the fuel cell 10, the air (oxygen) passing through the separator 11 (air flow path 11a) reacts with the hydrogen gas G passing through the separator 12 (hydrogen flow path 12a) to generate water in the air flow path 11a, and this water is discharged from the separator 11 together with the exhaust gas (air reacted with hydrogen). Therefore, in the power generation system 1 of this example, in order to prevent a large amount of moisture from being sucked into the pump 2 and causing an operational malfunction, the air from which moisture has been separated (from which moisture has been removed) from the air discharged from the separator 11 is sucked into the pump 2, and the water separated in the gas-liquid separation tank 3 is stored in a water tank 4a described later and used to humidify the hydrogen gas G. The upper part of this gas-liquid separation tank 3 is connected to the intake port of the pump 2 via pipes Pa3, Pb0-Pb4, a humidifier 4, heating sections 5a, 5b and pipes Pc1-Pc4, and the bottom part is connected to a water tank 4a in the humidifier 4 (described later) via pipe Pw1.

[0043] The humidifier 4 is an example of a "humidifier" and is configured to be able to humidify the hydrogen gas G supplied from the hydrogen gas supply source X to the fuel cell 10 (separator 12). Specifically, as shown in FIG. 2, the humidifier 4 includes a water tank 21, a nozzle 22, spheres 23, 23..., spiral tubes 24, 25, and a water tank 4a (see FIG. 1), and is configured to be able to humidify the hydrogen gas G passing through the water tank 21 by a bubbling process. The water tank 21 is a sealed container which is an example of a "water tank", and is configured to be able to store water W (pure water as an example) for humidifying the hydrogen gas G. The nozzle 22 is disposed on the bottom side of the water tank 21 so that the hydrogen gas G supplied from the hydrogen gas supply source X through the pipe Pg1 can be discharged into the water tank 21. The spheres 23, 23... are members for preventing liquid water W from being discharged from the water tank 21 into the piping Pg2 along with the hydrogen gas G, and are formed into small spheres of a material and structure that can generate buoyancy relative to the water W stored in the water tank 21, and are contained in the water tank 21.

[0044] The spiral pipe 24 corresponds to a "first heat exchange section that heats the water in the water tank by heat exchange with the first gas discharged from the first separator" and a "heat exchange section A that heats the water in the water tank by heat exchange with the third gas discharged from the third separator" (an example of a configuration in which one heat exchange section serves as both the "first heat exchange section" and the "heat exchange section A"). The spiral pipe 24 is housed in the water tank 21 so as to be immersed in the water W stored in the water tank 21, and is connected to one end of the spiral pipe 24 and to the other end of the spiral pipe Pb1, so that the water W can be heated by heat exchange between the air and the water W by passing air sucked from the separators 11 and 14 by the pump 2 through the spiral pipe 24.

[0045] The spiral tube 25 corresponds to the "second heat exchange section that heats the water in the water tank by heat exchange with the first gas discharged from the first suction pump" and the "heat exchange section B that heats the water in the water tank by heat exchange with the third gas discharged from the second suction pump" (an example of a configuration in which one heat exchange section serves as both the "second heat exchange section" and the "heat exchange section B"). This spiral tube 25 is accommodated in the water tank 21 so as to be immersed in the water W stored in the water tank 21, similar to the spiral tube 24, and is connected to one end of the spiral tube 25 and to the other end of the spiral tube 25, so that the water W can be heated by heat exchange between the air and the water W by passing air discharged from the pump 2 and pumped through the pipes Pd0 and Pd1.

[0046] As shown in Fig. 1, the water tank 4a is connected to the water tank 21 via a pipe Pw2, and is configured to store water W poured in advance or water W separated in the gas-liquid separation tank 3 as described above, and to supply the water W to the water tank 21 via the pipe Pw2. In this case, the power generation system 1 of this example is configured such that, as an example, a water level sensor is provided to detect the amount of water W stored in the water tank 21, and when the water level of the water W in the water tank 21 falls below a specified amount based on a sensor signal from the water level sensor, the control unit 9 controls the control valve 8b provided in the pipe Pw2 to an open state to supply the water W from the water tank 4a to the water tank 21. Also, as an example, the power generation system 1 of this example is configured such that the water tank 4a is provided above the water tank 21, and the water W in the water tank 4a flows into the water tank 21 via the pipe Pw2 due to its own weight. When it is difficult to install the water tank 4a above the water tank 21, a configuration can be adopted in which a liquid transfer pump is provided in the pipe Pw2 to cause the water W in the water tank 4a to flow into the water tank 21.

[0047] As shown in FIG. 3, the heating section 5a includes a spiral tube 31 (an example of a configuration in which one heat exchange section serves as both the "third heat exchange section" and the "heat exchange section C"), which is an example of a "third heat exchange section that heats the second gas to be introduced into the humidifier by heat exchange with the first gas discharged from the first separator" and a "heat exchange section C that heats the second gas to be introduced into the humidifier by heat exchange with the third gas discharged from the third separator", a spiral tube 32 (an example of a configuration in which one heat exchange section serves as both the "fourth heat exchange section" and the "heat exchange section D"), which is an example of a "fourth heat exchange section that heats the second gas to be introduced into the humidifier by heat exchange with the first gas discharged from the first suction pump" and a "heat exchange section D that heats the second gas to be introduced into the humidifier by heat exchange with the third gas discharged from the second suction pump", and a thermal insulation material 33.

[0048] In the heating section 5a, the pipe Pg1 is inserted through the center of the winding of both helical tubes 31, 32, and both helical tubes 31, 32 and the pipe Pg1 through which they are inserted are covered with a heat insulating material 33 to be insulated from the surrounding air. In this case, the helical tube 31 has one end connected to the pipe Pb2 connected to the pipe Pb0 and the other end connected to the pipe Pc2 connected to the pipe Pc4. The helical tube 32 has one end connected to the pipe Pd2 connected to the pipe Pd0 and the other end connected to the pipe Pe2 whose one end is open to the atmosphere.

[0049] As shown in FIG. 4, the heating section 5b includes a spiral tube 41 (an example of a configuration in which one heat exchange section serves as both the "fifth heat exchange section" and the "heat exchange section E") which is an example of a "fifth heat exchange section that heats the second gas discharged from the humidifier by heat exchange with the first gas discharged from the first separator" and a "heat exchange section E that heats the second gas discharged from the humidifier by heat exchange with the third gas discharged from the third separator", a spiral tube 42 (an example of a configuration in which one heat exchange section serves as both the "sixth heat exchange section" and the "heat exchange section F") which is an example of a "sixth heat exchange section that heats the second gas discharged from the humidifier by heat exchange with the first gas discharged from the first suction pump" and a "heat exchange section F that heats the second gas discharged from the humidifier by heat exchange with the third gas discharged from the second suction pump", and a thermal insulating material 43.

[0050] In the heating section 5b, the pipe Pg2 is inserted through the center of the winding of both helical tubes 41, 42, and both helical tubes 41, 42 and the pipe Pg2 through which they are inserted are covered with a heat insulating material 43 to be insulated from the surrounding air. The helical tube 41 has one end connected to a pipe Pb3 connected to a pipe Pb0 and the other end connected to a pipe Pc3 connected to a pipe Pc4. The helical tube 42 has one end connected to a pipe Pd3 connected to a pipe Pd0 and the other end connected to a pipe Pe3 whose one end is open to the atmosphere.

[0051] 1, the control valve 6a is disposed in the above-mentioned pipe Pb1, and adjusts the amount of air sucked from the separators 11, 14 by the pump 2 into the humidifier 4 (spiral tube 24) (the amount of air passed through the water tank 21) under the control of the control unit 9. The control valve 6b is disposed in the above-mentioned pipe Pb2, and adjusts the amount of air sucked from the separators 11, 14 by the pump 2 into the heating unit 5a (spiral tube 31) under the control of the control unit 9. The control valve 6c is disposed in the above-mentioned pipe Pb3, and adjusts the amount of air sucked from the separators 11, 14 by the pump 2 into the heating unit 5b (spiral tube 41) under the control of the control unit 9. The control valve 6d is disposed in the pipe Pb4 which directly connects the above pipes Pb0 and Pc4, and adjusts the amount of air sucked from the separators 11 and 14 by the pump 2 and flowing into the pump 2 without passing through the humidifier 4 or the heating units 5a and 5b under the control of the control unit 9.

[0052] The control valve 7a is disposed in the above-mentioned pipe Pd1, and adjusts the amount of air discharged from the pump 2 flowing into the humidifier 4 (spiral tube 25) (the amount of air passed through the water tank 21) according to the control of the control unit 9. The control valve 7b is disposed in the above-mentioned pipe Pd2, and adjusts the amount of air discharged from the pump 2 flowing into the heating unit 5a (spiral tube 32) according to the control of the control unit 9. The control valve 7c is disposed in the above-mentioned pipe Pd3, and adjusts the amount of air discharged from the pump 2 flowing into the heating unit 5b (spiral tube 42) according to the control of the control unit 9. The control valve 7d is disposed in the pipe Pd4 that directly releases the air discharged from the pump 2 into the pipe Pd0 into the atmosphere, and adjusts the amount of air discharged from the pump 2 into the atmosphere without passing through the humidifier 4 or the heating units 5a and 5b according to the control of the control unit 9.

[0053] The control valve 8a is disposed in the above-mentioned pipe Pw1, and allows / restricts the flow of the water W from the gas-liquid separation tank 3 to the water tank 4a under the control of the control unit 9. The control valve 8b is disposed in the above-mentioned pipe Pw2, and allows / restricts the inflow of the water W from the water tank 4a to the water tank 21 under the control of the control unit 9.

[0054] The control unit 9 performs overall control of the power generation system 1. Specifically, the control unit 9 controls the pump 2 to suck air from the separators 11, 14, thereby introducing new air into the separators 11, 14. Note that, as an example, the power generation system 1 of this example employs a configuration in which the control unit 9 adjusts the flow rate of hydrogen gas G introduced from the hydrogen gas supply source X to the fuel cell 10 (separator 12) by adjusting the opening degree of a flow rate adjustment valve (not shown) disposed in the above-mentioned piping Pg1; however, in order to facilitate understanding of the configuration and operation of the power generation system 1, detailed explanation of the flow rate adjustment of hydrogen gas G will be omitted.

[0055] The control unit 9 also controls the control valves 6a-6d, 7a-7d in accordance with the power generation environment of the fuel cell 10, which will be described later, to adjust the amount of air passing through the humidifier 4 and the heating units 5a, 5b. In this case, the power generation system 1 of this example includes, as an example, a temperature sensor for detecting the temperature of the fuel cell 10, a temperature sensor for detecting the temperature of the hydrogen gas G supplied to the fuel cell 10 (separator 12), a temperature sensor for detecting the temperature of the water W in the humidifier 4, and a temperature sensor for detecting the temperature of the air discharged from the pump 2 (none of which are shown), and the control unit 9 controls the control valves 6a-6d, 7a-7d in accordance with the temperatures detected by these temperature sensors. The control of the pump 2 by the control unit 9, the flow rate adjustment of the hydrogen gas G, and the control of the control valves 6a-6d, 7a-7d, etc. will be described in detail later.

[0056] In this power generation system 1, as described above, air (oxygen) and hydrogen gas G (hydrogen) are reacted in the fuel cell 10 to generate power. Specifically, when an instruction to start power generation is given by operating an operation unit (not shown), the control unit 9 controls the pump 2 to start sucking in air (oxygen). In this case, at this point in time immediately after the start of power generation and when the temperatures of the fuel cell 10 and the pump 2 have not yet risen, the control unit 9, as one example, transitions the control valves 6a-6c to a closed state and transitions the control valve 6d to an open state, transitions the control valves 7a-7c to a closed state and transitions the control valve 7d to an open state.

[0057] At this time, air is sucked from the separator 11 (air flow path 11a) via pipes Pc4, Pb4, Pb0, Pa3, the gas-liquid separation tank 3, and pipe Pa2, so that new air is introduced into the separator 11 (air flow path 11a) via pipe Pa1, and air is sucked from the separator 14 (air flow path 14a) via pipes Pc4, Pb4, Pb0, Pa5, so that new air is introduced into the separator 14 (air flow path 14a) via pipe Pa4. The air sucked into the pump 2 is released into the atmosphere via pipes Pd0 and Pd4.

[0058] In this state, by starting the supply of hydrogen gas G from the hydrogen gas supply source X, the hydrogen gas G is introduced into the separator 12 (hydrogen flow path 12a) via the pipe Pg1, the humidifier 4, and the pipe Pg2. The hydrogen gas G introduced into the separator 12 is passed through the hydrogen flow path 12a and then sent to a post-treatment device (not shown) via the pipe Pg3. As a result, electricity is generated by a reaction between the air (oxygen) passed through the air flow path 11a and the hydrogen gas G (hydrogen) passed through the hydrogen flow path 12a.

[0059] In this case, in the power generation system 1 of this example, in order to prevent the hydrogen gas G discharged from the hydrogen gas supply source X from drying up the MEA 13 when the hydrogen gas G is supplied to the fuel cell 10 (separator 12) and causing a decrease in power generation efficiency, a configuration is adopted in which the hydrogen gas G discharged from the hydrogen gas supply source X is humidified in the humidifier 4 before being supplied to the fuel cell 10 (separator 12). Specifically, the hydrogen gas G supplied from the hydrogen gas supply source X to the humidifier 4 through the pipe Pg1 and discharged from the nozzle 22 into the water tank 21 absorbs moisture when rising in the water W in the water tank 21, thereby increasing its relative humidity. In addition, the hydrogen gas G that has risen to the vicinity of the water surface passes between the spheres 23, 23, and is discharged to the pipe. As a result, the humidified hydrogen gas G is supplied to the fuel cell 10 (separator 12) through the pipe Pg2 without causing a situation in which a large amount of the water W in the water tank 21 is discharged together with the hydrogen gas G.

[0060] Here, for a while after the start of power generation, the amount of hydrogen gas G supplied to the fuel cell 10 is small, so the hydrogen gas G can be sufficiently humidified by floating the room temperature water W in the humidifier 4 (water tank 21). However, in order to transition the power generation system 1 to a steady operation state and increase the amount of power generation, it becomes necessary to supply a large amount of hydrogen gas G to the fuel cell 10 to react with a large amount of air (oxygen), so it becomes difficult to sufficiently humidify the hydrogen gas G supplied to the fuel cell 10 by simply floating the room temperature water W. Therefore, in the power generation system 1 of this example, a configuration is adopted in which, when the amount of hydrogen gas G supplied to the fuel cell 10 is increased, the temperature of the water W and the temperature of the hydrogen gas G itself are raised to maintain an appropriate humidity (sufficient humidity that does not cause the MEA 13 to dry up).

[0061] Specifically, when air is sucked by the pump 2 with the start of power generation, the temperature of the air discharged to the pipe Pd0 rises due to compression by the pump 2 and mechanical heat generation by the pump 2. Therefore, in the power generation system 1 of this example, a configuration is adopted in which the water W and hydrogen gas G are heated using the heat of the air discharged from the pump 2, thereby sufficiently humidifying the hydrogen gas G to be supplied to the separator 12. More specifically, the control unit 9 first switches the control valves 7a to 7c to an open state and switches the control valve 7d to a closed state. At this time, the high-temperature air discharged from the pump 2 to the pipe Pd0 is supplied to the humidifier 4 via the pipe Pd1, supplied to the heating unit 5a via the pipe Pd2, and supplied to the heating unit 5b via the pipe Pd3.

[0062] At this time, in the humidifier 4, the air supplied via the pipe Pd1 is passed through the spiral tube 25, and the temperature of the water W in the water tank 21 is increased by heat exchange with the air in the spiral tube 25. This makes the water W more likely to change into a gas phase, and the hydrogen gas G that is ejected from the nozzle 22 into the water W and floats in the water W is suitably humidified. In addition, the air that has been passed through the spiral tube 25 and has its temperature reduced by heat exchange with the water W is released into the atmosphere via the pipe Pe1.

[0063] In addition, in the heating unit 5a, the air supplied through the pipe Pd2 is passed through the spiral tube 32, and the hydrogen gas G flowing from the hydrogen gas supply source X to the humidifier 4 in the pipe Pg1 through which the spiral tube 32 is inserted is heated by heat exchange with the air in the spiral tube 32. As a result, the relative humidity of the hydrogen gas G introduced into the humidifier 4 (in the water tank 21) is reduced, and the hydrogen gas G is easily absorbed in the humidifier 4. In addition, the hydrogen gas G whose temperature is increased in the heating unit 5a is introduced into the humidifier 4, and as a result, the water W in the water tank 21 is also heated, and the water W is easily changed into a gas phase. Therefore, the hydrogen gas G can be sufficiently humidified in the humidifier 4. In addition, the air whose temperature is reduced by heat exchange with the hydrogen gas G after passing through the spiral tube 32 is released into the atmosphere through the pipe Pe2.

[0064] In addition, in the heating section 5b, the air supplied via the pipe Pd3 is passed through the spiral tube 42, and the temperature of the hydrogen gas G flowing from the humidifier 4 to the fuel cell 10 (separator 12) in the pipe Pg2 through which the spiral tube 42 is inserted is increased by heat exchange with the air in the spiral tube 42. In this case, the hydrogen gas G sufficiently humidified in the humidifier 4 has a relative humidity of about 100% when it is discharged from the humidifier 4 to the pipe Pg2. For this reason, when the hydrogen gas G humidified in the humidifier 4 is directly supplied to the fuel cell 10 (separator 12), condensation may occur due to changes in temperature and pressure in the pipe Pg2 or the separator 12, and liquid-phase moisture may be present in the hydrogen flow path 12a, hindering the passage of the hydrogen gas G. Therefore, the power generation system 1 of this example employs a configuration in which the relative humidity is reduced by increasing the temperature of the hydrogen gas G humidified in the humidifier 4 prior to supplying the hydrogen gas G to the separator 12. This makes it possible to avoid condensation caused by changes in temperature or humidity in the pipe Pg2 or the separator 12. In addition, the air that has been passed through the spiral tube 42 and has been reduced in temperature by heat exchange with the hydrogen gas G is released into the atmosphere via the pipe Pe3.

[0065] On the other hand, after a certain amount of time has passed since the start of power generation, the temperature of the fuel cell 10 rises due to heat generated by the reaction between the air (oxygen) and hydrogen gas G (hydrogen), and the temperature of the air discharged from the separators 11, 14 rises due to heat exchange with the fuel cell 10 (separators 11, 14). Therefore, in the power generation system 1 of this example, a configuration is adopted in which the heat of the air discharged from the separators 11, 14 is used to heat the water W and hydrogen gas G, thereby sufficiently heating the hydrogen gas G supplied to the separator 12.

[0066] Specifically, the control unit 9 switches the control valves 6a to 6c to an open state and switches the control valve 6d to a closed state. At this time, the high-temperature air discharged from the separator 11 to the pipe Pa2 and then to the pipe Pb0 via the gas-liquid separation tank 3 and the pipe Pa3 and the high-temperature air discharged from the separator 14 to the pipe Pa5 and then to the pipe Pb0 are merged in the pipe Pb0, and this air is supplied to the humidifier 4 via the pipe Pb1, supplied to the heating unit 5a via the pipe Pb2, and supplied to the heating unit 5b via the pipe Pb3.

[0067] At this time, in the humidifier 4, the air supplied via the pipe Pb1 is passed through the spiral tube 24, and the temperature of the water W in the water tank 21 is increased by heat exchange with the air in the spiral tube 24. This makes the water W more likely to change into a gas phase, and the hydrogen gas G that is ejected from the nozzle 22 into the water W and floats in the water W is suitably humidified. In addition, the air that has been passed through the spiral tube 24 and has its temperature reduced by heat exchange with the water W is sucked into the pump 2 via the pipes Pc1 and Pc4.

[0068] In addition, in the heating unit 5a, the air supplied through the pipe Pb2 is passed through the spiral tube 31, and the hydrogen gas G flowing from the hydrogen gas supply source X to the humidifier 4 in the pipe Pg1 through which the spiral tube 31 is inserted is heated by heat exchange with the air in the spiral tube 31. As a result, the relative humidity of the hydrogen gas G introduced into the humidifier 4 (in the water tank 21) is reduced, making it easier for the hydrogen gas G to absorb moisture in the humidifier 4. In addition, the temperature of the water W in the water tank 21 is also increased by heat exchange with the hydrogen gas G whose temperature has been increased in the heating unit 5a, making it easier for the water W to change into a gas phase. Therefore, the hydrogen gas G can be sufficiently humidified in the humidifier 4. In addition, the air whose temperature has been reduced by heat exchange with the hydrogen gas G after passing through the spiral tube 31 is sucked into the pump 2 through the pipes Pc2 and Pc4.

[0069] Furthermore, in the heating section 5b, the air supplied via the pipe Pb3 is passed through the spiral tube 41, whereby the temperature of the hydrogen gas G flowing from the humidifier 4 toward the fuel cell 10 (separator 12) in the pipe Pg2 through which the spiral tube 41 is inserted is increased by heat exchange with the air in the spiral tube 41. This reduces the relative humidity before the hydrogen gas G humidified in the humidifier 4 is supplied to the separator 12, making it possible to prevent condensation due to changes in temperature or humidity in the pipe Pg2 or the separator 12. The air that has been passed through the spiral tube 41 and has its temperature reduced by heat exchange with the hydrogen gas G is sucked into the pump 2 via the pipes Pc3 and Pc4.

[0070] In practice, the control unit 9 adjusts the humidity of the hydrogen gas G supplied to the fuel cell 10 (separator 12) by arbitrarily opening and closing the control valves 6a-6d, 7a-7d in accordance with the amount of hydrogen gas G supplied to the fuel cell 10 (separator 12), the temperature of the hydrogen gas G discharged from the hydrogen gas supply source X, the temperature of the water W in the water tank 21, and the temperature of the hydrogen gas G supplied to the fuel cell 10 (separator 12). For example, when the amount of hydrogen gas G supplied to the separator 12 is small and the hydrogen gas G can be sufficiently humidified by the water W at room temperature in the humidifier 4, either or both of the control valves 6a, 7a are shifted to a closed state to continue power generation without heating the water W, or either or both of the control valves 6b, 7b are shifted to a closed state to continue power generation without heating the hydrogen gas G.

[0071] When the temperature of the hydrogen gas G discharged from the hydrogen gas supply source X is sufficiently high and the hygroscopicity of the hydrogen gas G is sufficiently high, either or both of the control valves 6b and 7b are shifted to the closed state to continue power generation without heating the hydrogen gas G. When the temperature of the water W in the water tank 21 is sufficiently high and is in a state in which it is easy to change into a gas phase, either or both of the control valves 6a and 7a are shifted to the closed state to continue power generation without heating the water W. When the temperature of the hydrogen gas G supplied to the fuel cell 10 (separator 12) is sufficiently high and there is no risk of condensation occurring in the pipe Pg2 or the separator 12, either or both of the control valves 6c and 7c are shifted to the closed state to continue power generation without heating the hydrogen gas G. These controls make it possible to generate power without causing the MEA 13 to dry up, regardless of changes in the amount of power generation (i.e., the amount of hydrogen gas G supplied to the fuel cell 10) or changes in the operating environment of the power generation system 1 (changes in the ambient temperature, etc.).

[0072] On the other hand, in this type of power generation system, water is generated in the air flow path due to the reaction between oxygen and hydrogen in the fuel cell. In this case, air containing liquid-phase moisture may be sucked into the pump, which may cause the pump to malfunction. For this reason, the power generation system 1 of this example employs a configuration in which the water W generated in the fuel cell 10 (separator 11) during power generation is separated from the air in the gas-liquid separation tank 3 and removed. Specifically, when air containing liquid-phase water W (water droplets) generated during power generation is discharged from the separator 11, the air flows into the gas-liquid separation tank 3 through the pipe Pa2, and is separated into air and water W in the gas-liquid separation tank 3. The separated water W is stored in the gas-liquid separation tank 3, and the air is discharged from the gas-liquid separation tank 3 into the pipe Pa3 and is sucked into the pump 2 together with the air discharged from the separator 14 as described above. This makes it possible to suitably avoid a situation in which air containing water W (water droplets) is sucked into the pump 2.

[0073] In addition, the power generation system 1 of this embodiment employs a configuration in which the water W separated in the gas-liquid separation tank 3 is used for humidification in the humidifier 4. Specifically, when the control unit 9 determines that a specified amount of water W is stored in the gas-liquid separation tank 3 based on a sensor signal from a water level sensor (not shown) disposed in the gas-liquid separation tank 3, the control unit 9 controls the control valve 8a to an open state. At this time, the water W in the gas-liquid separation tank 3 is liquid-transferred to the water tank 4a via the pipe Pw1 by a liquid-transfer pump (not shown) disposed in the pipe Pw1 or by the weight of the water W. As a result, when the amount of water W stored in the humidifier 4 (water tank 21) falls below a specified amount, the control unit 9 controls the control valve 8b to an open state, so that sufficient water W is supplied from the water tank 4a to the water tank 21 via the pipe Pw2 to maintain a state in which the hydrogen gas G can be suitably humidified.

[0074] Thus, the power generation system 1 has a water tank 21 through which hydrogen gas G to be supplied to the separator 12 can pass, and is equipped with a humidifier 4 that humidifies the hydrogen gas G passed through the water tank 21, and the humidifier 4 is equipped with a spiral tube 24 that heats the water W in the water tank 21 by heat exchange with the air discharged from the separator 11. Therefore, according to the power generation system 1, by utilizing the heat of the air (air discharged from the separator 11) whose temperature has increased due to heat generated by the fuel cell 10 during power generation, the water W in the water tank 21 can be heated to a state that is easy to vaporize without consuming electricity to humidify the hydrogen gas G, unlike a configuration in which water for humidification is heated by an electric heater, and the hydrogen gas G that is caused to float in the water W can be suitably humidified, thereby sufficiently improving the power generation efficiency in the power generation system 1. Furthermore, the temperature of the fuel cell 10 rises in response to an increase in the amount of hydrogen gas G supplied to the fuel cell 10, i.e., an increase in the amount of power generated by the power generation system 1, and this causes the temperature of the air discharged from the separator 11 to rise, so that by heating the water W through heat exchange with this air, the water W can be heated more appropriately when the amount of hydrogen gas G to be humidified by the humidifier 4 is greater. This allows the hydrogen gas G to be humidified appropriately without the need for complicated control.

[0075] The power generation system 1 also includes a pump 2 that draws air from the separator 11 to introduce new air into the separator 11, and a humidifier 4 includes a spiral tube 25 that heats the water W in the water tank 21 by heat exchange with the air discharged from the pump 2. Therefore, the power generation system 1 can use not only the heat of the air whose temperature has increased due to heat generation by the fuel cell 10, but also the heat of the air (air discharged from the pump 2) whose temperature has increased due to compression by the pump 2 and mechanical heat generation by the pump 2, thereby more suitably heating the water W in the water tank 21 without consuming power for humidifying the hydrogen gas G. In addition, the amount of air drawn (compressed) by the pump 2 increases in response to an increase in the amount of hydrogen gas G supplied to the fuel cell 10, i.e., an increase in the amount of power generated by the power generation system 1, and this increases the temperature of the air discharged from the pump 2. By heating the water W by heat exchange with this air, the water W can be heated more suitably when the amount of hydrogen gas G to be humidified by the humidifier 4 is greater.

[0076] The power generation system 1 also includes a heating section 5a having a spiral tube 31 that heats the hydrogen gas G introduced into the humidifier 4 by heat exchange with the air discharged from the separator 11. Therefore, according to the power generation system 1, the relative humidity of the hydrogen gas G introduced into the humidifier 4 is reduced by utilizing the heat of the air (air discharged from the separator 11) whose temperature has increased due to heat generated by the fuel cell 10 during power generation, and this allows the humidification to be suitably increased by sufficiently increasing the hygroscopicity in the humidifier 4. As a result, even if the amount of water W stored in the humidifier 4 (water storage tank 21) is small, the hydrogen gas G can be suitably humidified and drying up of the MEA 13 in the fuel cell 10 can be suitably prevented. Therefore, the amount of stored water W can be reduced and the amount of heat consumed to heat the water W (the amount of heat exchange between the air discharged from the separator 11 and the water W) can be reduced, and as a result, a situation in which the amount of heat required to suitably humidify the hydrogen gas G is insufficient can be suitably avoided.

[0077] The power generation system 1 also includes a spiral tube 32 that heats the hydrogen gas G to be introduced into the humidifier 4 by heat exchange with the air discharged from the pump 2. Therefore, the power generation system 1 can sufficiently reduce the relative humidity of the hydrogen gas G to be introduced into the humidifier 4 by utilizing not only the heat of the air whose temperature has been increased by the heat generated by the fuel cell 10, but also the heat of the air (air discharged from the pump 2) whose temperature has been increased by compression by the pump 2 and mechanical heat generated by the pump 2. This can reliably avoid a situation in which the amount of heat required to suitably humidify the hydrogen gas G is insufficient.

[0078] This power generation system 1 also includes a heating section 5b having a spiral tube 41 that heats the hydrogen gas G discharged from the humidifier 4 by heat exchange with the air discharged from the separator 11. Therefore, according to this power generation system 1, the relative humidity of the hydrogen gas G introduced into the separator 12 can be reduced by utilizing the heat of the air (air discharged from the separator 11) whose temperature has increased due to heat generated by the fuel cell 10 during power generation, and it is possible to suitably prevent condensation from occurring in the hydrogen flow path 12a, etc.

[0079] The power generation system 1 also includes a heating section 5b having a spiral tube 42 that heats the hydrogen gas G discharged from the humidifier 4 by heat exchange with the air discharged from the pump 2. Therefore, according to the power generation system 1, the relative humidity of the hydrogen gas G introduced into the separator 12 can be reduced by utilizing not only the heat of the air whose temperature has been increased by heat generation from the fuel cell 10, but also the heat of the air (air discharged from the pump 2) whose temperature has been increased by compression by the pump 2 and mechanical heat generation by the pump 2, and it is possible to suitably avoid a situation in which condensation occurs within the hydrogen flow path 12a, etc.

[0080] The power generation system 1 also includes a water tank 21 through which the hydrogen gas G to be supplied to the separator 12 can pass, and a humidifier 4 that humidifies the hydrogen gas G that is passed through the water tank 21, and the humidifier 4 includes a spiral tube 24 that heats the water W in the water tank 21 by heat exchange with the air discharged from the separator 14. Therefore, according to the power generation system 1, by utilizing the heat of the air (air discharged from the separator 14) whose temperature has increased due to the heat generated by the fuel cell 10 during power generation, the water W in the water tank 21 can be heated to a state that is easy to vaporize without consuming electricity to humidify the hydrogen gas G, unlike a configuration in which the water for humidification is heated by an electric heater, and the hydrogen gas G that is caused to float in the water W can be suitably humidified, thereby sufficiently improving the power generation efficiency in the power generation system 1. Furthermore, the temperature of the fuel cell 10 rises in response to an increase in the amount of hydrogen gas G supplied to the fuel cell 10, i.e., an increase in the amount of power generated by the power generation system 1, and this causes the temperature of the air discharged from the separator 14 to rise, and by heating the water W through heat exchange with this air, the water W can be heated more appropriately when the amount of hydrogen gas G to be humidified by the humidifier 4 is greater. This allows the hydrogen gas G to be humidified appropriately without the need for complicated control.

[0081] The power generation system 1 also includes a pump 2 that draws air from the separator 14 to introduce new air into the separator 14, and the humidifier 4 includes a spiral tube 25 that heats the water W in the water tank 21 by heat exchange with the air discharged from the pump 2. Therefore, the power generation system 1 can use not only the heat of the air whose temperature has increased due to the heat generated by the fuel cell 10, but also the heat of the air (air discharged from the pump 2) whose temperature has increased due to compression by the pump 2 and mechanical heat generated by the pump 2, thereby more suitably heating the water W in the water tank 21 without consuming power for humidifying the hydrogen gas G. In addition, the amount of air drawn (compressed) by the pump 2 increases in response to an increase in the amount of hydrogen gas G supplied to the fuel cell 10, i.e., an increase in the amount of power generated by the power generation system 1, and this causes the temperature of the air discharged from the pump 2 to rise. By heating the water W by heat exchange with this air, the water W can be heated more suitably when the amount of hydrogen gas G to be humidified by the humidifier 4 is greater.

[0082] The power generation system 1 also includes a heating section 5a having a spiral tube 31 that heats the hydrogen gas G introduced into the humidifier 4 by heat exchange with the air discharged from the separator 14. Therefore, according to the power generation system 1, the relative humidity of the hydrogen gas G introduced into the humidifier 4 is reduced by utilizing the heat of the air (air discharged from the separator 14) whose temperature has increased due to heat generated by the fuel cell 10 during power generation, thereby enabling the humidification to be suitably increased. As a result, even if the amount of water W stored in the humidifier 4 (water storage tank 21) is small, the hydrogen gas G can be suitably humidified and drying up of the MEA 13 in the fuel cell 10 can be suitably prevented. Therefore, the amount of stored water W can be reduced and the amount of heat consumed to heat the water W (the amount of heat exchange between the air discharged from the separator 14 and the water W) can be reduced, and as a result, a situation in which the amount of heat required to suitably humidify the hydrogen gas G is insufficient can be suitably avoided.

[0083] The power generation system 1 also includes a heating section 5a having a spiral tube 32 that heats the hydrogen gas G to be introduced into the humidifier 4 by heat exchange with the air discharged from the pump 2. Therefore, the power generation system 1 can sufficiently reduce the relative humidity of the hydrogen gas G to be introduced into the humidifier 4 by utilizing not only the heat of the air whose temperature has been increased by the heat generated by the fuel cell 10, but also the heat of the air (air discharged from the pump 2) whose temperature has been increased by compression by the pump 2 and mechanical heat generated by the pump 2. This can reliably avoid a situation in which the amount of heat required to suitably humidify the hydrogen gas G is insufficient.

[0084] The power generation system 1 also includes a heating section 5b having a spiral tube 41 that heats the hydrogen gas G discharged from the humidifier 4 by heat exchange with the air discharged from the separator 14. Therefore, according to the power generation system 1, the relative humidity of the hydrogen gas G introduced into the separator 12 can be reduced by utilizing the heat of the air (air discharged from the separator 14) whose temperature has increased due to heat generated by the fuel cell 10 during power generation, and condensation can be suitably prevented from occurring in the hydrogen flow path 12a, etc.

[0085] The power generation system 1 also includes a heating section 5b having a spiral tube 42 that heats the hydrogen gas G discharged from the humidifier 4 by heat exchange with the air discharged from the pump 2. Therefore, according to the power generation system 1, the relative humidity of the hydrogen gas G introduced into the separator 12 can be reduced by utilizing not only the heat of the air whose temperature has been increased by heat generation from the fuel cell 10, but also the heat of the air (air discharged from the pump 2) whose temperature has been increased by compression by the pump 2 and mechanical heat generation by the pump 2, and it is possible to suitably avoid a situation in which condensation occurs within the hydrogen flow path 12a, etc.

[0086] The configuration of the "power generation system" is not limited to the example of the power generation system 1 described above.

[0087] For example, a configuration has been described in which air is sucked from separators 11, 14 by one pump 2 to introduce new air into separators 11, 14 (a configuration in which one pump serves as both the "first pump" and the "second pump"), but a configuration in which the "first pump" and the "second pump" are separately provided and the "first pump" sucks the "first gas" from the "first separator" while the "third pump" sucks the "third gas" from the "third separator" (not shown) can also be adopted. Also, instead of the suction-type pump 2, a pressure-type pump can be provided at the inlet of separator 11 or the inlet of separator 14 to introduce air into separator 11 or separator 14 (not shown).

[0088] In addition, the configuration in which the air sucked from the separators 11, 14 is joined and passed through the humidifier 4 (the spiral tube 24 serving as both the "first heat exchange section" and the "heat exchange section A") has been described as an example, but the "first heat exchange section" and the "heat exchange section A" can also be provided separately (not shown). In addition, the configuration in which the air sucked from the separators 11, 14 is joined and passed through the heating section 5a (the spiral tube 31 serving as both the "third heat exchange section" and the "heat exchange section C") has been described as an example, but the "third heat exchange section" and the "heat exchange section C" can also be provided separately (not shown). In addition, although an example has been described in which the air sucked from separators 11 and 14 is joined and passed through heating section 5b (spiral tube 41 serving as both the "fifth heat exchange section" and the "heat exchange section E"), the "fifth heat exchange section" and the "heat exchange section E" can also be arranged separately (not shown).

[0089] In addition, the configuration in which the air sucked from separators 11, 14 is joined and passed through humidifier 4 (spiral tube 25 serving as both the "second heat exchange section" and "heat exchange section B") has been described as an example, but the "second heat exchange section" and "heat exchange section B" can also be provided separately (not shown). In addition, the configuration in which the air sucked from separators 11, 14 is joined and passed through heating section 5a (spiral tube 32 serving as both the "fourth heat exchange section" and "heat exchange section D") has been described as an example, but the "fourth heat exchange section" and "heat exchange section D" can also be provided separately (not shown). In addition, although an example has been described in which the air sucked from separators 11 and 14 is joined and passed through heating section 5b (spiral tube 42 serving as both the "sixth heat exchange section" and "heat exchange section F"), the "sixth heat exchange section" and "heat exchange section F" can also be arranged separately (not shown).

[0090] It is also possible to adopt a configuration (not shown) that does not utilize the heat of the air discharged from separator 11, a configuration (not shown) that does not utilize the heat of the air discharged from separator 14, and a configuration (not shown) that does not utilize the heat of the air discharged from pump 2. [Explanation of symbols]

[0091] 1. Power generation system 2. Pump 3 Gas-liquid separation tank 4 Humidifier 4a Water tank 5a,5b Heating section 6a~6c, 7a~7c, 8a, 8b Control valves 9. Control Unit 10 Fuel Cell 11,12,14 Separator 11a Air flow path 12a Hydrogen flow path 13 MEA 14a Air flow path a 21 Water tank 22 Nozzle 23 Sphere 24,25,31,32,41,42 spiral tube 33,43 Insulation Pa1~Pa5, Pb0~Pb4, Pc1~Pc4, Pd0~Pd4, Pe1~Pe3, Pg1~Pg3, Pw1, Pw2 Piping G Hydrogen gas W water X Hydrogen gas source

Claims

1. A power generation system including a power generation cell which is configured to generate power by stacking and integrating 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 plurality of flat plate-like laminated objects including at least the membrane electrode assembly disposed between the first separator and the second separator, and which is capable of generating power by reacting the first gas with the second gas via the membrane electrode assembly, a humidifier having a water tank through which the second gas to be supplied to the second separator can pass and humidifying the second gas that is passed through the water tank; The humidifier comprises a first heat exchanger that heats the water in the water tank by heat exchange with the first gas discharged from the first separator.

2. a first suction pump configured to introduce new first gas into the first separator by sucking the first gas from the first separator; The power generation system according to claim 1 , wherein the humidifier includes a second heat exchanger that heats the water in the water tank by heat exchange with the first gas discharged from the first suction pump.

3. 2. The power generation system according to claim 1, further comprising a third heat exchanger that heats the second gas to be introduced into the humidifier by heat exchange with the first gas discharged from the first separator.

4. 3. The power generation system according to claim 2, further comprising a fourth heat exchanger that heats the second gas to be introduced into the humidifier by heat exchange with the first gas discharged from the first suction pump.

5. 2. The power generation system according to claim 1, further comprising a fifth heat exchanger that heats the second gas discharged from the humidifier by heat exchange with the first gas discharged from the first separator.

6. 3. The power generation system according to claim 2, further comprising a sixth heat exchanger that heats the second gas discharged from the humidifier by heat exchange with the first gas discharged from the first suction pump.

7. A power generation system including a power generation cell which is configured to generate power by stacking and integrating 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 plurality of flat plate-like laminated objects including at least the membrane electrode assembly disposed between the first separator and the second separator, and which is capable of generating power by reacting the first gas with the second gas via the membrane electrode assembly, a humidifier having a water tank through which the second gas to be supplied to the second separator can pass and humidifying the second gas that is passed through the water tank; the power generation cell includes a third separator as the laminated object, the third separator being formed to allow a third gas to pass therethrough and configured to be able to cool the power generation cell by heat exchange with the third gas; The humidifier includes a heat exchange unit A that heats the water in the water tank by heat exchange with the third gas discharged from the third separator.

8. a second suction pump that introduces new third gas into the third separator by sucking the third gas from the third separator; The power generation system according to claim 7 , wherein the humidifier includes a heat exchanger B that heats the water in the water tank by heat exchange with the third gas discharged from the second suction pump.

9. 8. The power generation system according to claim 7, further comprising a heat exchange section C for heating the second gas to be introduced into the humidifier by heat exchange with the third gas discharged from the third separator.

10. 9. The power generation system according to claim 8, further comprising a heat exchanger D for heating the second gas to be introduced into the humidifier by heat exchange with the third gas discharged from the second suction pump.

11. The power generation system according to claim 7 , further comprising a heat exchange section E for heating the second gas discharged from the humidifier by heat exchange with the third gas discharged from the third separator.

12. The power generation system according to claim 8 , further comprising a heat exchange section F that heats the second gas discharged from the humidifier by heat exchange with the third gas discharged from the second suction pump.

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