Fuel cell system

Abstract

To provide a fuel cell system that suppresses the generation of white smoke in the exhaust.SOLUTION: A fuel cell system includes a fuel cell unit having a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen, and an air mixing unit in which exhaust gas discharged from the fuel cell unit is mixed with air and the exhaust gas is diluted with the air and discharged to the outside, the air mixing unit includes a water receiver at a lower part for collecting condensed water formed when water vapor in the diluted exhaust gas is condensed, and a drainage unit provided in the water receiver and discharging the accumulated condensed water to the outside.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to fuel cell systems. [Background technology]

[0002] Patent Document 1 discloses a packaged fuel cell power generation system that houses in one package a reformer, a battery that reacts hydrogen and oxygen to obtain electric energy, a heat exchanger for maintaining reaction conditions and increasing plant efficiency, and a control system. Patent Document 1 discloses that the fuel cell power generation system is provided with a cooling means that cools the plant exhaust after recovering heat and water from the reformer exhaust gas and the battery exhaust air before releasing it into the atmosphere, and condenses and recovers water vapor in the plant exhaust.

[0003] Patent Document 2 discloses a fuel cell power generation system that includes all of the main equipment of the power generation system, including a fuel cell, a fuel reformer, etc., and a generated water recovery device that condenses and recovers generated water contained in the air off-gas of the fuel cell and the combustion exhaust gas of the fuel reformer. Patent Document 2 discloses that all of the main equipment in the fuel cell system and the generated water recovery device are housed together in a package that is forcibly ventilated by a ventilation fan. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 09-223510 [Patent Document 2] Japanese Patent Application Publication No. 08-293316 Summary of the Invention [Problem to be solved by the invention]

[0005] Stationary fuel cell systems are often installed in places where they are visible to the public. When stationary fuel cell systems emit white smoke during exhaust, this can be unpleasant for some people.

[0006] The present disclosure provides a fuel cell system that suppresses the generation of white smoke in the exhaust. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, there is provided a fuel cell system comprising: a fuel cell section having a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen; and an air mixing section in which exhaust gas discharged from the fuel cell section is mixed with air and the exhaust gas is diluted with the air and discharged to the outside, the air mixing section comprising a water receiver in a lower portion for collecting condensed water formed by condensation of water vapor in the diluted exhaust gas, and a drainage section provided in the water receiver for discharging the accumulated condensed water to the outside. Effect of the Invention

[0008] According to the fuel cell system of the present disclosure, the generation of white smoke in the exhaust can be suppressed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an outline of the configuration of a fuel cell system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an outline of the configuration of a fuel cell system according to a second embodiment. [Diagram 3] FIG. 3 is a diagram showing an outline of the configuration of a fuel cell system according to a third embodiment. [Figure 4] FIG. 4 is a diagram showing an outline of the configuration of a fuel cell system according to a fourth embodiment. [Diagram 5] FIG. 5 is a diagram showing an outline of the configuration of a fuel cell system according to a fifth embodiment. [Figure 6] FIG. 6 is a diagram showing an outline of the configuration of a fuel cell system according to a sixth embodiment. [Figure 7] FIG. 7 is a diagram illustrating the process in the fuel cell system according to the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0011] In addition, in the description of the specification and drawings of each embodiment, components having substantially the same or corresponding functional configurations may be denoted by the same reference numerals to avoid redundant explanation. In addition, in order to facilitate understanding, the scale of each part in the drawings may differ from the actual scale.

[0012] In the directions of parallel, right-angle, orthogonal, horizontal, vertical, up-down, left-right, front-back, etc., deviations are permitted to the extent that they do not impair the effects of the embodiment. The shape of the corners is not limited to right angles and may be rounded. Parallel, right-angle, orthogonal, horizontal, and vertical may include approximately parallel, approximately right-angle, approximately orthogonal, approximately horizontal, and approximately vertical, respectively.

[0013] For example, "approximately parallel" means that even if two lines or two surfaces are not completely parallel to each other, they can be treated as parallel to each other as long as it is within the range of manufacturing tolerance. As with "approximately parallel," "approximately right angle," "approximately perpendicular," "approximately horizontal," and "approximately vertical" are also intended to correspond to the respective terms as long as the relative positional relationship between the two lines or two surfaces is within the range of manufacturing tolerance.

[0014] First Embodiment <Fuel cell system> A fuel cell system according to the first embodiment will be described. The fuel cell system according to the first embodiment includes a fuel cell unit having a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen, and an air mixing unit in which exhaust gas discharged from the fuel cell unit is mixed with air and diluted exhaust gas in which the exhaust gas is diluted with the air is discharged to the outside. The air mixing unit in the fuel cell system according to the first embodiment includes a water receiver in a lower portion for collecting condensed water formed by condensation of water vapor in the diluted exhaust gas, and a drainage unit provided in the water receiver for discharging the collected condensed water to the outside.

[0015] A fuel cell system according to a first embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing an outline of the configuration of a fuel cell system 1, which is an example of the fuel cell system according to the first embodiment.

[0016] The fuel cell system 1 is a system that generates electricity using a fuel cell unit 10 that generates electricity by chemically reacting hydrogen and oxygen. The fuel cell system 1 supplies the generated electricity to a destination.

[0017] The fuel cell system 1 includes a fuel cell section 10, a housing 20 in which the fuel cell section 10 is provided in an internal space 21, and an air mixing section 30. The fuel cell system 1 is a packaged fuel cell system including the fuel cell section 10 inside the housing 20.

[0018] [Fuel cell section 10] The fuel cell section 10 includes a fuel cell stack 10a that generates electricity by chemically reacting hydrogen with oxygen. The fuel cell stack 10a generates electricity by chemically reacting supplied hydrogen with oxygen contained in the air. The fuel cell stack 10a is, for example, a polymer electrolyte fuel cell (PEFC). The fuel cell stack 10a, which is a polymer electrolyte fuel cell, has a stack structure in which a large number of unit cells are stacked.

[0019] A single cell in the fuel cell stack 10a, which is a polymer electrolyte fuel cell, includes a membrane electrode assembly (MEA) having a polymer electrolyte membrane and a pair of electrodes provided on both sides of the polymer electrolyte membrane. The polymer electrolyte membrane selectively transports hydrogen ions. Each electrode is formed of a porous material. Each of the pair of electrodes includes a catalyst layer mainly composed of carbon powder supporting a platinum-based metal catalyst (electrode catalyst), and a gas diffusion layer having both air permeability and electronic conductivity. Furthermore, the single cell includes a pair of separators that sandwich the membrane electrode assembly (MEA) from both sides.

[0020] The electricity generated by the fuel cell stack 10a is boosted and output to the outside.

[0021] The exhaust gas EA generated after the reaction between hydrogen and oxygen in the fuel cell section 10 passes through an exhaust pipe 11 and is discharged from the air mixing section 30 .

[0022] The fuel cell unit 10 may be connected to the outside through piping so that the water Wfc discharged from the exhaust gas EA after gas-liquid separation is discharged to the outside together with condensed water W, which will be described later. The exhaust pipe 11 may be connected to the outside through piping so that the condensed water Wp that accumulates in the exhaust pipe 11 as a result of condensation of moisture contained in the exhaust gas EA is discharged to the outside together with the condensed water W, which will be described later. When discharging the condensed water Wp from the exhaust pipe 11, the piping may be provided below the exhaust pipe 11. The same applies to the embodiments described below.

[0023] [Case 20] The housing 20 has a box-like shape with an internal space 21. The housing 20 has an air intake port 20a that takes in air from the outside of the housing 20 into the internal space 21, and an air exhaust port 20b that exhausts air from the internal space 21 to the outside.

[0024] The fuel cell system 1 is provided with an intake fan 22 at the intake port 20a for drawing air from the outside into the internal space 21. The air VA supplied from the intake port 20a passes through the internal space 21 as shown by the arrow. Then, the air VA is exhausted from the exhaust port 20b to the air mixing section 30.

[0025] [Air mixing section 30] The air mixer 30 mixes the air VA that ventilates the internal space 21 in the housing 20 with the exhaust air EA discharged from the fuel cell section 10. By mixing the air VA with the exhaust air EA, the air mixer 30 dilutes the exhaust air EA with the air VA. In the air mixer 30, the diluted exhaust air DA obtained by diluting the exhaust air EA with the air VA is exhausted to the outside of the fuel cell system 1 from an exhaust port 30a.

[0026] The air mixing section 30 includes a housing 31 , a water receiver 32 , and a water separating section 33 .

[0027] The housing 31 is provided to cover the exhaust port 20b in the housing 20 and to form an exhaust port 30a through which the diluted exhaust gas DA is exhausted to the outside of the fuel cell system 1.

[0028] The housing 31 bends the flow direction of the air VA and the exhaust air EA horizontally in FIG. 1, so that the air VA and the exhaust air EA are mixed in the area RA in FIG. 1. The exhaust air EA has a temperature of about 70° C., for example. On the other hand, the air VA that ventilates the internal space 21 is heated by the fuel cell section 10 and the like, and therefore has a temperature slightly higher than room temperature, for example, about 30° C. Therefore, the exhaust air EA is cooled by the air VA. The exhaust air EA contains water vapor. Therefore, when the exhaust air EA is cooled by the air VA, the water vapor contained in the exhaust air EA condenses.

[0029] Condensed water W formed by condensation of water vapor contained in the exhaust air EA accumulates in the water receiver 32 due to its own weight. In addition, the condensed water W formed by condensation of water vapor contained in the exhaust air EA is separated by the water separation section 33 and flows down into the water receiver 32. The condensed water W accumulated in the water receiver 32 is discharged to the outside from the drain section 32a.

[0030] According to the fuel cell system of the first embodiment, the generation of white smoke can be suppressed by mixing exhaust gas and air in the air mixing section. Also, according to the fuel cell system of the first embodiment, the condensed water produced by condensing water vapor in the air mixing section is stored in a water receiver, so that, for example, the inside of the housing can be prevented from becoming flooded with water.

[0031] The housing 20 is an example of a first housing, the housing 31 is an example of a second housing, and the exhaust port 30a is an example of a first exhaust port.

[0032] Second Embodiment <Fuel cell system> A description will now be given of a fuel cell system according to a second embodiment. In the fuel cell system according to the second embodiment, the housing of the air mixing section in the fuel cell system according to the first embodiment contains a heat insulating material.

[0033] The fuel cell system according to the second embodiment will be described with reference to the drawings. Fig. 2 is a diagram showing an outline of the configuration of a fuel cell system 2, which is an example of the fuel cell system according to the second embodiment.

[0034] The fuel cell system 2 includes an air mixing section 130 instead of the air mixing section 30 in the fuel cell system 1 .

[0035] [Air mixing section 130] The air mixer 130 mixes the air VA that ventilates the internal space 21 in the housing 20 with the exhaust air EA discharged from the fuel cell section 10. By mixing the air VA with the exhaust air EA, the air mixer 130 dilutes the exhaust air EA with the air VA. In the air mixer 130, the diluted exhaust air DA obtained by diluting the exhaust air EA with the air VA is exhausted to the outside of the fuel cell system 2 from an exhaust port 130a.

[0036] The air mixer 130 includes a housing 131, a water receiver 32, and a water separator 33. For the water receiver 32 and the water separator 33, refer to the description of the fuel cell system 1, and description thereof will be omitted here.

[0037] The housing 131 is provided to cover the exhaust port 20b in the housing 20 and to form an exhaust port 130a that exhausts the diluted exhaust gas DA to the outside of the fuel cell system 2. The housing 131 is made of a thermal insulating material. In other words, the housing 131 includes a thermal insulating material.

[0038] By forming the housing 131 from a heat insulating material, it is possible to prevent, for example, condensation on the inner surface of the housing 131. By preventing condensation on the inner surface of the housing 131, it is possible to prevent, for example, condensed water droplets from entering the internal space 21 through the exhaust port 20b.

[0039] According to the fuel cell system of the second embodiment, the generation of white smoke can be suppressed by mixing exhaust gas and air in the air mixing section. Also, according to the fuel cell system of the second embodiment, the condensed water produced by condensation of water vapor in the air mixing section is stored in a water receiver, so that, for example, the inside of the housing can be prevented from becoming flooded with water. Furthermore, according to the fuel cell system of the second embodiment, condensation in the air mixing section can be prevented.

[0040] Third Embodiment <Fuel cell system> A fuel cell system according to a third embodiment will be described. In the fuel cell system according to the third embodiment, the top plate of the housing of the air mixing unit in the fuel cell system according to the first embodiment is inclined so that the exhaust port side is lower. Also, in the fuel cell system according to the third embodiment, the housing of the air mixing unit in the fuel cell system according to the first embodiment is provided with a water return (or liquid return) above the water receiver near the second exhaust port on the top plate.

[0041] The fuel cell system according to the third embodiment will be described with reference to the drawings. Fig. 3 is a diagram showing an outline of the configuration of a fuel cell system 3, which is an example of the fuel cell system according to the third embodiment.

[0042] The fuel cell system 3 includes an air mixing section 230 instead of the air mixing section 30 in the fuel cell system 1 .

[0043] [Air mixing section 230] The air mixer 230 mixes the air VA that ventilates the internal space 21 in the housing 20 with the exhaust air EA discharged from the fuel cell section 10. By mixing the air VA with the exhaust air EA, the air mixer 230 dilutes the exhaust air EA with the air VA. In the air mixer 230, the diluted exhaust air DA obtained by diluting the exhaust air EA with the air VA is exhausted to the outside of the fuel cell system 3 from the exhaust port 230a.

[0044] The air mixer 230 includes a housing 231, a water receiver 32, and a water separator 33. For the water receiver 32 and the water separator 33, refer to the description of the fuel cell system 1, and description thereof will be omitted here.

[0045] The housing 231 is provided to cover the exhaust port 20b in the housing 20 and to form an exhaust port 230a that exhausts the diluted exhaust gas DA to the outside of the fuel cell system 3. The top plate 231a of the housing 231 is inclined so that the exhaust port 230a side is lower. The housing 231 also includes a water return 231b on the top plate 231a near the exhaust port 230a and above the water receiver 32.

[0046] The top plate 231a of the housing 231 is inclined so that the exhaust port 230a side is lower, so that, for example, the condensed water W1 formed on the inner surface of the top plate 231a can be moved along the incline and flowed by the water return 231b into the water receiver 32. By moving the condensed water W1 formed on the inner surface of the top plate 231a along the incline and flowing it by the water return 231b into the water receiver 32, the condensed water W1 formed on the top plate 231a can be collected.

[0047] According to the fuel cell system of the third embodiment, the generation of white smoke can be suppressed by mixing exhaust gas and air in the air mixing section. Also, according to the fuel cell system of the third embodiment, the condensed water generated by condensing water vapor in the air mixing section is stored in a water receiver, so that, for example, the inside of the housing can be prevented from becoming flooded with water. Furthermore, according to the fuel cell system of the third embodiment, the condensed water formed on the top plate of the air mixing section can be collected.

[0048] The exhaust port 230a is an example of a second exhaust port.

[0049] Fourth Embodiment <Fuel cell system> The following describes a fuel cell system according to a fourth embodiment. The fuel cell system according to the fourth embodiment is the fuel cell system according to the first embodiment, but includes a plurality of fuel cell units in a housing.

[0050] A fuel cell system according to a fourth embodiment will be described with reference to the drawings. Fig. 4 is a diagram showing an outline of the configuration of a fuel cell system 4, which is an example of the fuel cell system according to the fourth embodiment.

[0051] The fuel cell system 4 includes a plurality of fuel cell sections 310. The exhaust EA from the plurality of fuel cell sections 310 may join one exhaust pipe 11 and be exhausted from the air mixing section 30, or each of the plurality of fuel cell sections 310 may be individually connected to the air mixing section 30. Note that, in FIG. 4, the fuel cell system 4 includes three fuel cell sections 310, but the number of fuel cell sections included in the fuel cell system according to the fourth embodiment is not limited to three. For example, the fuel cell system according to the fourth embodiment may include two fuel cell sections, or may include four or more fuel cell sections.

[0052] According to the fuel cell system of the fourth embodiment, the generation of white smoke can be suppressed by mixing exhaust gas and air in the air mixing section. Also, according to the fuel cell system of the fourth embodiment, the condensed water produced by condensing water vapor in the air mixing section is stored in a water receiver, so that, for example, the inside of the housing can be prevented from becoming flooded with water. Furthermore, according to the fuel cell system of the fourth embodiment, since it is provided with multiple fuel cell sections 310, the output of the fuel cell system can be increased.

[0053] Fifth embodiment <Fuel cell system> A fuel cell system according to a fifth embodiment will be described. The fuel cell system according to the fifth embodiment includes a fuel cell unit having a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen, and an air mixing unit in which exhaust gas discharged from the fuel cell unit is mixed with air and the diluted exhaust gas in which the exhaust gas is diluted with the air is discharged to the outside. The air mixing unit in the fuel cell system according to the fifth embodiment includes a water receiver in a lower portion thereof for collecting condensed water formed by condensation of water vapor in the diluted exhaust gas, and a drainage unit provided in the water receiver for discharging the collected condensed water to the outside. Furthermore, the fuel cell system according to the fifth embodiment includes a first housing in which the fuel cell unit and the air mixing unit are provided, and a ventilation fan that supplies air inside the first housing to the air mixing unit. Furthermore, the air mixing unit in the fuel cell system according to the fifth embodiment includes a moisture removal unit that removes moisture contained in the diluted exhaust gas. Moreover, the drainage unit in the fuel cell system according to the fifth embodiment includes a leakage prevention unit that prevents the diluted exhaust gas from leaking out.

[0054] A fuel cell system according to a fifth embodiment will be described with reference to the drawings. Fig. 5 is a diagram showing an outline of the configuration of a fuel cell system 1, which is an example of a fuel cell system according to a fifth embodiment.

[0055] The fuel cell system 5 includes a fuel cell section 10, a housing 420 in which the fuel cell section 10 is provided in an internal space 421, and an air mixing section 430 provided in the internal space 421 of the housing 420. The fuel cell system 5 is a packaged fuel cell system including the fuel cell section 10 inside the housing 420. The description of the fuel cell section 10 can be referred to in the fuel cell system 1, and a description thereof will be omitted here.

[0056] [Chassis 420] Housing 420 has a box-like shape with internal space 421. Housing 420 has air intake port 420a that takes in air from the outside of housing 420 into internal space 421, and air exhaust port 420b that exhausts air from internal space 421 to the outside via air mixing section 430. Housing 420 has umbrella section 425 to prevent rain or the like from entering inside housing 420 through air exhaust port 420b.

[0057] The fuel cell system 5 includes a ventilation fan 435 for discharging air in the internal space 421 from the exhaust port 420b via the air mixing section 430. Air VA supplied from the intake port 20a passes through the internal space 421 as shown by the arrow. Then, the air VA is supplied to the air mixing section 430 by the ventilation fan 435. Then, the air VA is discharged from the exhaust port 420b.

[0058] [Air mixing section 430] The air mixer 430 mixes the air VA in the internal space 421 of the housing 420 with the exhaust air EA discharged from the fuel cell section 10. By mixing the air VA with the exhaust air EA, the air mixer 430 dilutes the exhaust air EA with the air VA. The diluted exhaust air DA obtained by diluting the exhaust air EA with the air VA in the air mixer 30 is exhausted to the outside of the fuel cell system 5 from the exhaust port 420b.

[0059] The air mixing section 430 includes a housing 431 , a water receiver 432 , a water separating section 433 , and a leakage prevention section 434 .

[0060] The housing 431 has a cylindrical shape and is provided in the internal space 421. Exhaust air EA is introduced from the fuel cell unit 10 through the exhaust pipe 11 into the housing 431. In addition, air VA is introduced into the housing 431 by a ventilation fan 435. In the area RA in FIG. 5, the air VA and the exhaust air EA are mixed. The exhaust air EA has a temperature of about 70° C., for example. On the other hand, the air VA ventilating the internal space 421 has a temperature slightly higher than room temperature, for example, about 30° C., because it is heated by the fuel cell unit 10 and the like. Therefore, the exhaust air EA is cooled by the air VA. The exhaust air EA contains water vapor. Therefore, when the exhaust air EA is cooled by the air VA, the water vapor contained in the exhaust air EA is condensed.

[0061] Condensed water W formed by condensation of water vapor contained in the exhaust air EA accumulates in the water receiver 432 due to its own weight. Also, the condensed water W formed by condensation of water vapor contained in the exhaust air EA is separated by the water separation section 433 and flows down into the water receiver 432. The condensed water W accumulated in the water receiver 432 is discharged to the outside from the drainage section 432a. The water receiver 432 includes a leakage prevention section 434 to prevent the diluted exhaust air DA from leaking out from the drainage section 432a. The leakage prevention section 434 is, for example, a U-shaped pipe.

[0062] According to the fuel cell system of the fifth embodiment, the generation of white smoke can be suppressed by mixing exhaust gas and air in the air mixing section. Also, according to the fuel cell system of the fifth embodiment, the condensed water produced by condensing water vapor in the air mixing section is stored in a water receiver, so that, for example, the inside of the housing can be prevented from being flooded with water.

[0063] Incidentally, the housing 420 is an example of a first housing.

[0064] Sixth Embodiment <Fuel cell system> A fuel cell system according to a sixth embodiment will be described. The fuel cell system according to the sixth embodiment includes a ventilation fan that supplies air to the air mixing section, and a wetness sensor located near the exhaust port, in addition to the fuel cell system according to the fifth embodiment. The wetness sensor may be a hygrometer. Furthermore, in the fuel cell system according to the sixth embodiment, the rotation speed is controlled based on the detection result of the wetness sensor.

[0065] A fuel cell system according to a sixth embodiment will be described with reference to the drawings. Fig. 6 is a diagram showing an outline of the configuration of a fuel cell system 6, which is an example of the fuel cell system according to the sixth embodiment.

[0066] The fuel cell system 6 includes the components of the fuel cell system 5, further including a wetness sensor 541, a controller 542, and an inverter 543.

[0067] The wetness sensor 541 detects whether the moisture concentration is increasing due to moisture contained in the diluted exhaust gas DA. The wetness sensor 541 may be a sensor that detects surface wetness, or may be a humidity sensor. The wetness sensor 541 is provided near the exhaust port 420b. It is desirable to provide the wetness sensor 541 in a location that is not affected by raindrops, for example, under the umbrella part 425. The wetness sensor 541 outputs the detection result to the controller 542.

[0068] The controller 542 controls the ventilation fan 435 based on the detection result of the wetness sensor 541. Specifically, when the wetness sensor 541 detects wetness, the controller 542 increases the number of rotations of the ventilation fan 435. On the other hand, when the wetness sensor 541 does not detect wetness, the controller 542 decreases the number of rotations of the ventilation fan 435. In the case of the humidity sensor, when the humidity is equal to or higher than any humidity in the range from 80% to 100%, preferably equal to or higher than 90%, the controller 542 increases the number of rotations of the ventilation fan 435. On the other hand, when the humidity sensor detects a humidity equal to or lower than any humidity in the range from 50% to 80%, preferably equal to or lower than 80%, the controller 542 decreases the number of rotations of the ventilation fan 435.

[0069] The controller 542 outputs a control signal to the inverter 543. The inverter 543 outputs, based on the control signal output from the controller 542, to the ventilation fan 435, a drive signal having a frequency that results in a desired number of rotations.

[0070] A description will now be given of an example of the operation of the fuel cell system 6. Fig. 7 is a diagram illustrating the processing in the fuel cell system 6, which is an example of a fuel cell system according to the sixth embodiment.

[0071] 7, the horizontal axis conceptually indicates time, and the vertical axis conceptually indicates the detection result of the wetness sensor 541 and the number of rotations (rotation frequency) of the ventilation fan 435.

[0072] The line Ls indicates the detection result of the wetness sensor 541. A low level output (OFF) on the line Ls indicates that wetness is not detected, i.e., the diluted exhaust gas DA is dry. A high level output (ON) on the line Ls indicates that wetness is detected, i.e., the diluted exhaust gas DA is wet.

[0073] When wetness is detected by the wetness sensor 541, the controller 542 increases the number of rotations (rotation frequency) of the ventilation fan 435 at a predetermined increase rate. When the number of rotations of the ventilation fan 435 increases, the amount of air VA contained in the diluted exhaust air DA increases, and therefore the humidity in the diluted exhaust air DA decreases. By decreasing the humidity in the diluted exhaust air DA, condensation of water vapor contained in the diluted exhaust air DA can be suppressed.

[0074] When wetness is not detected by the wetness sensor 541, the controller 542 reduces the number of rotations (rotation frequency) of the ventilation fan 435 at a predetermined reduction rate. By reducing the number of rotations of the ventilation fan 435, the power consumed by the ventilation fan 435 can be reduced.

[0075] The absolute value of the increase rate should be greater than the absolute value of the decrease rate. By making the absolute value of the increase rate greater than the absolute value of the decrease rate, the generation of white smoke in the diluted exhaust gas DA can be suppressed.

[0076] According to the fuel cell system of the sixth embodiment, the generation of white smoke can be suppressed by mixing exhaust gas and air in the air mixing section. Also, according to the fuel cell system of the sixth embodiment, the condensed water produced by condensing water vapor in the air mixing section is stored in a water receiver, so that, for example, the inside of the housing can be prevented from becoming flooded with water. Furthermore, according to the fuel cell system of the sixth embodiment, the power consumption of the exhaust fan is optimized, allowing efficient operation.

[0077] As described above, the embodiment has been described, but the above embodiment is presented as an example, and the present invention is not limited to the above embodiment. The above embodiment can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0078] 1, 2, 3, 4, 5, 6 Fuel Cell System 10, 310 Fuel cell section 10a Fuel Cell Stack 11 Exhaust pipe 20, 420 case 20a, 420a Intake 20b, 420b exhaust port 21, 421 Interior space 22 Intake fan 30, 130, 230, 430 Air mixing section 30a, 130a, 230a exhaust port 31, 131, 231, 431 housing 32 Water Receiver 32a, 432a Drainage section 33, 433 Water separation section 231a Tabletop 434 Leakage prevention part 435 Ventilation Fan 541 Sensors 542 Controller 543 Inverter DA Dilution Exhaust EA Exhaust VA Air W Condensed water

Claims

1. a fuel cell unit including a fuel cell stack that generates electricity by chemically reacting hydrogen and oxygen; an air mixing section in which the exhaust gas discharged from the fuel cell section is mixed with air and the exhaust gas is diluted with the air to produce diluted exhaust gas, which is discharged to the outside; Equipped with The air mixing section includes a water receiver at a lower portion thereof for collecting condensed water formed by condensing water vapor in the diluted exhaust gas, and a drainage section provided in the water receiver for discharging the collected condensed water to the outside. Fuel cell system.

2. a first housing in which the fuel cell unit is provided, the first housing has an intake port for taking in air from the outside and a first exhaust port for discharging air to the outside, The air mixing section dilutes the exhaust gas with the air discharged from the first exhaust port. The fuel cell system according to claim 1 .

3. The air mixing unit includes a second housing that covers the first exhaust port and forms a second exhaust port that discharges the diluted exhaust gas to the outside. The fuel cell system according to claim 2 .

4. The second housing includes a thermal insulating material. The fuel cell system according to claim 3 .

5. a top plate of the second housing is inclined so that a side of the second exhaust port is lower; The second housing includes a water return located near the second exhaust port on the top plate and above the water receiver. The fuel cell system according to claim 3 .

6. a first housing in which the fuel cell section and the air mixing section are provided and which has an exhaust port for discharging the diluted exhaust gas from the air mixing section to the outside; a ventilation fan that supplies air inside the first housing to the air mixing section, The air mixing section includes a water separation section that separates water contained in the diluted exhaust gas, The drainage section includes a leakage prevention section that prevents the diluted exhaust gas from leaking out. The fuel cell system according to claim 1 .

7. A wetness sensor is provided in the vicinity of the exhaust port, The rotation speed of the ventilation fan is controlled based on the detection result of the wetness sensor. The fuel cell system according to claim 6.

8. A plurality of the fuel cell units are provided, A plurality of the fuel cell units are connected to the air mixing unit. The fuel cell system according to any one of claims 1 to 7.

Images