JP2017117518A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system capable of being configured simply and compactly, and also successfully suppressing an oxidant gas circulating in a water storage unit from being bypassed and exhausted.SOLUTION: A fuel cell system 10 comprises a fuel cell stack 14, an oxidant gas supply pipe 46a which supplies an oxidant gas to the fuel cell stack 14, and an oxidant gas exhaust pipe 46b which exhausts the oxidant gas from the fuel cell stack 14. The oxidant gas supply pipe 46a is arranged with a water storage tank 50, and the oxidant gas exhaust pipe 46b is arranged with a gas-liquid separator 62. A water distribution pipe 66 is provided to circulate liquid water from the gas-liquid separator 62 to the water storage tank 50.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system including a fuel cell, an oxidant gas supply pipe, and an oxidant gas discharge pipe.

  For example, a polymer electrolyte fuel cell has an electrolyte membrane / electrode structure (MEA) in which an anode electrode is disposed on one surface of an electrolyte membrane made of a polymer ion exchange membrane and a cathode electrode is disposed on the other surface. It has. The electrolyte membrane / electrode structure is sandwiched between separators to constitute a power generation cell (unit cell). Usually, a predetermined number of power generation cells are stacked, and for example, they are incorporated in a fuel cell vehicle (fuel cell electric vehicle or the like) as an in-vehicle fuel cell stack.

  In a fuel cell, a fuel gas (hydrogen gas) is supplied to an anode electrode and an oxidant gas (air) is supplied to a cathode electrode to generate electric power by an electrochemical reaction between the fuel gas and the oxidant gas. Yes. At that time, in order to appropriately humidify the electrolyte membrane, for example, the oxidant gas is supplied to the fuel cell in a pre-humidified state.

  For example, in the fuel cell system disclosed in Patent Document 1, a humidifying module (humidifier) is arranged in parallel with the fuel cell stack, and the fuel cell is humidified with an oxidant gas supplied from an air compressor. Supplying to the stack. A humidifying module bypass flow path is provided to supply the oxidizing gas directly from the air compressor to the fuel cell stack without going through the humidifying module. A humidification module bypass valve (open / close valve) is disposed in the humidification module bypass flow path.

  In the fuel cell system disclosed in Patent Document 2, a humidifier is provided in a supply pipe that supplies air to the fuel cell and a discharge pipe that discharges exhaust gas (used air) from the fuel cell. ing. The supply pipe is provided with a bypass supply pipe for bypassing the humidifier, and a gate valve (open / close valve) is attached to the bypass supply pipe. Furthermore, the atomizer which has the ultrasonic transducer | vibrator which atomizes internal water is arrange | positioned at the air exhaust system. When the atomizer is operated to drive the air compressor, the water remaining in the fuel cell stack or the like is atomized and discharged.

JP 2009-158270 A Japanese Patent Laying-Open No. 2005-251576

  In Patent Document 1 and Patent Document 2 described above, a humidifier is disposed between the oxidant gas supply pipe and the oxidant gas discharge pipe, and a bypass supply pipe that bypasses the humidifier is provided. Further, an open / close valve is disposed in the bypass supply pipe.

  However, the humidifier is difficult to reduce in size and has a considerably large outer dimension. In addition, there is a bypass supply pipe in which an on-off valve is arranged, and there is a problem that the entire fuel cell system is enlarged.

  On the other hand, in said patent document 2, it is possible to provide an atomizer in a humidifier (gas-liquid separator), atomize the water | moisture content in the said humidifier, and humidify the air before supply. However, in such a configuration, the pre-use air supplied to the humidifier and the post-use air discharged from the fuel cell are mixed, and the pre-use air is discharged by bypassing the fuel cell. There is a risk.

  The present invention solves this type of problem, can be configured simply and compactly, and satisfactorily suppresses oxidant gas flowing through the water storage section from being discharged by bypassing the fuel cell. It is an object of the present invention to provide a fuel cell system that can be used.

  A fuel cell system according to the present invention includes a fuel cell that generates electric power by an electrochemical reaction between a fuel gas and an oxidant gas, an oxidant gas supply pipe that supplies the oxidant gas to the fuel cell, and the fuel cell An oxidant gas discharge pipe for discharging the oxidant gas.

  The fuel cell system includes a water storage unit disposed in the oxidant gas supply pipe and a gas-liquid separation unit disposed in the oxidant gas discharge pipe, and liquid water is supplied from the gas-liquid separation unit to the water storage unit. A water distribution unit is provided to distribute the water.

  Moreover, in this fuel cell system, it is preferable that the water reservoir is provided with an ultrasonic vibrator for atomizing the liquid water in the water reservoir and humidifying the oxidant gas.

  Furthermore, in this fuel cell system, it is preferable that the water distribution section has a water distribution pipe that connects the water storage section and the gas-liquid separation section, and an orifice is disposed in the water distribution pipe.

  Furthermore, in this fuel cell system, the drain opening that discharges the liquid water from the gas-liquid separator to the water distribution pipe is disposed above the water supply opening that introduces the liquid water from the water distribution pipe to the water storage section. It is preferable.

  Further, in this fuel cell system, the water storage part and the gas-liquid separation part are formed in the same casing, and the opening for communicating the water storage part and the gas-liquid separation part is provided in the gas-liquid separation part. It is preferably formed below the water level lower limit position.

  Further, in this fuel cell system, it is preferable that at least a part of the bottom surface of the gas-liquid separation unit is disposed above the bottom surface of the water storage unit and constitutes an inclined bottom surface that is inclined downward toward the water storage unit. .

  According to the present invention, the oxidant gas is supplied to the fuel cell after flowing through the water storage unit, while the used oxidant gas is discharged from the fuel cell to the gas-liquid separation unit, and the gas components and moisture are discharged. Have been separated. In the gas-liquid separation part, the separated water is condensed and the liquid water stays, and the liquid water is introduced into the water storage part through the water distribution part, and the oxidant gas before use can be humidified.

  Therefore, since the water storage unit and the gas-liquid separation unit are individually configured, the oxidant gas flowing through the water storage unit is well suppressed from being discharged by bypassing the fuel cell with a simple and compact configuration. It becomes possible to do.

1 is an explanatory diagram of a schematic configuration of a fuel cell system according to a first embodiment of the present invention. It is a schematic structure explanatory drawing of the fuel cell system concerning the 2nd Embodiment of this invention.

  As shown in FIG. 1, the fuel cell system 10 according to the first embodiment of the present invention is mounted on a fuel cell vehicle (not shown) such as a fuel cell electric vehicle, for example.

  The fuel cell system 10 includes a fuel cell stack 14 in which a plurality of power generation cells (fuel cells) 12 are stacked, an oxidant gas supply device 16 that supplies an oxidant gas to the fuel cell stack 14, and the fuel cell stack 14. And a fuel gas supply device 18 for supplying fuel gas to the fuel cell. The fuel cell system 10 further includes a cooling medium supply device (not shown) that supplies a cooling medium to the fuel cell stack 14.

  In the power generation cell 12, the electrolyte membrane / electrode structure 22 is sandwiched between the first separator 24 and the second separator 26. The first separator 24 and the second separator 26 are constituted by a metal separator or a carbon separator.

  The electrolyte membrane / electrode structure 22 includes, for example, a solid polymer electrolyte membrane 28 that is a thin film of perfluorosulfonic acid containing moisture, and an anode electrode 30 and a cathode electrode 32 that sandwich the solid polymer electrolyte membrane 28. Is provided. The solid polymer electrolyte membrane 28 uses a HC (hydrocarbon) electrolyte in addition to a fluorine electrolyte.

  The first separator 24 is provided with a fuel gas channel 34 for supplying fuel gas to the anode electrode 30 between the electrolyte membrane / electrode structure 22. The second separator 26 is provided with an oxidant gas flow path 36 for supplying an oxidant gas to the cathode electrode 32 between the electrolyte membrane / electrode structure 22. Between the first separator 24 and the second separator 26 adjacent to each other, a cooling medium flow path 38 is provided for circulating the cooling medium.

  One end plate 40a constituting the fuel cell stack 14 is individually communicated in the stacking direction of the power generation cells 12 to form an oxidant gas inlet communication hole 42a and an oxidant gas outlet communication hole 42b. In the other end plate 40b constituting the fuel cell stack 14, a fuel gas inlet communication hole 44a and a fuel gas outlet communication hole 44b are formed in communication with each other in the stacking direction of the power generation cells 12, respectively. Although not shown, the end plate 40a or the end plate 40b is individually connected in the stacking direction of the power generation cells 12 to form a cooling medium inlet communication hole and a cooling medium outlet communication hole.

  The oxidant gas inlet communication hole 42a and the oxidant gas outlet communication hole 42b communicate with the oxidant gas flow path 36 and circulate an oxidant gas, for example, an oxygen-containing gas (hereinafter also referred to as air). The fuel gas inlet communication hole 44a and the fuel gas outlet communication hole 44b communicate with the fuel gas flow path 34 and allow a fuel gas, for example, a hydrogen-containing gas (hereinafter also referred to as hydrogen gas) to flow therethrough.

  The oxidant gas supply device 16 includes an oxidant gas supply pipe 46 a that communicates with the oxidant gas inlet communication hole 42 a of the fuel cell stack 14 and an oxidant gas that communicates with the oxidant gas outlet communication hole 42 b of the fuel cell stack 14. And a discharge pipe 46b. An air compressor 48 is disposed on the upstream side of the oxidant gas supply pipe 46 a, and a water storage unit, for example, a water storage tank 50 is disposed on the downstream side of the air compressor 48.

  An oxidant gas introduction port 52a for introducing air from the oxidant gas supply pipe 46a to the water storage chamber 50R in the water storage tank 50 is formed at the upper side surface of the water storage tank 50. On the upper surface of the water storage tank 50, an oxidant gas outlet 52b for leading air from the water storage chamber 50R in the water storage tank 50 to the oxidant gas supply pipe 46a is formed.

  A liquid water supply port (water supply opening) 54 a and a liquid water discharge port 54 b are formed in the lower part of the side surface of the water storage tank 50. The liquid water discharge port 54b is separated vertically upward (in the direction of arrow A) from the liquid water supply port 54a, so that the water level ws in the water storage tank 50 is set to a predetermined position. Maintain a constant amount of water storage. The water storage tank 50 is disposed on the ultrasonic transducer 56, and the ultrasonic transducer 56 is mounted on the installation surface 60 via the rubber mount 58.

  The oxidant gas discharge pipe 46 b is connected to the off-gas supply port 63 on the upper surface of the gas-liquid separator (gas-liquid separator) 62. The gas-liquid separator 62 is disposed separately from the water storage tank 50 and above the water storage tank 50.

  A drain opening 64 is formed in the lower part of the side surface of the gas-liquid separator 62. A water distribution pipe 66 is connected to the drain opening 64 and the liquid water supply port 54a. The drainage opening 64 for discharging liquid water from the gas-liquid separator 62 to the water distribution pipe 66 is separated by a distance h above the liquid water supply port 54a for introducing the liquid water from the water distribution pipe 66 to the water storage tank 50. Arranged.

  An exhaust opening 68 is formed in the upper part of the side surface of the gas-liquid separator 62, and an exhaust pipe 70 is connected to the exhaust opening 68. A pressure adjustment valve 72 is disposed in the exhaust pipe 70. One end of a drain pipe 74 is located downstream of the pressure adjustment valve 72 and communicates with the exhaust pipe 70, and the other end of the drain pipe 74 communicates with the liquid water outlet 54 b of the water storage tank 50.

  An orifice 76a is disposed near the liquid water supply port 54a of the water distribution pipe 66, while an orifice 76b is disposed near the liquid water discharge port 54b of the drain pipe 74. This is to prevent backflow of air.

  The fuel gas supply device 18 includes a fuel gas supply pipe 78a that communicates with the fuel gas inlet communication hole 44a of the fuel cell stack 14, and a fuel gas discharge pipe 78b that communicates with the fuel gas outlet communication hole 44b of the fuel cell stack 14. Have. A hydrogen tank 80 for storing high-pressure hydrogen is disposed on the upstream side of the fuel gas supply pipe 78a, and a shut-off valve 82 and an ejector 84 are disposed on the downstream side of the hydrogen tank 80.

  The fuel gas discharge pipe 78 b guides fuel exhaust gas, which is fuel gas at least partially used in the anode electrode 30, from the fuel cell stack 14. A circulation channel 86 is branched from the downstream side of the fuel gas discharge pipe 78 b, and the circulation channel 86 is connected to the ejector 84. The fuel gas discharge pipe 78b is provided with a purge valve 88 located downstream of the circulation passage 86.

  The operation of the fuel cell system 10 configured as described above will be described below.

  Air is sent to the oxidant gas supply pipe 46 a through the air compressor 48 that constitutes the oxidant gas supply device 16. This air is introduced into the water storage chamber 50R in the water storage tank 50, and then supplied from the oxidant gas outlet 52b to the oxidant gas inlet communication hole 42a of the fuel cell stack 14 through the oxidant gas supply pipe 46a. .

  On the other hand, in the fuel gas supply device 18, hydrogen gas is supplied from the hydrogen tank 80 to the fuel gas supply piping 78 a under the opening action of the shut-off valve 82. The hydrogen gas passes through the ejector 84 and is then supplied to the fuel gas inlet communication hole 44 a of the fuel cell stack 14.

  The air supplied to the oxidant gas inlet communication hole 42 a of the fuel cell stack 14 is introduced into the oxidant gas flow path 36 constituting each power generation cell 12 and supplied to the cathode electrode 32. On the other hand, the hydrogen gas supplied to the fuel gas inlet communication hole 44 a of the fuel cell stack 14 is introduced into the fuel gas flow path 34 constituting each power generation cell 12 and supplied to the anode electrode 30.

  Therefore, in each electrolyte membrane / electrode structure 22, the air supplied to the cathode electrode 32 and the hydrogen gas supplied to the anode electrode 30 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. .

  In the cooling medium supply device (not shown), the cooling medium supplied to the cooling medium inlet communication hole of the fuel cell stack 14 is supplied to the cooling medium flow path 38 between the power generation cells 12, and each electrolyte membrane / electrode structure is provided. Cool 22.

  Next, the oxidant exhaust gas, which is air that is supplied to the cathode electrode 32 and partially consumed, is discharged from the oxidant gas outlet communication hole 42 b of the fuel cell stack 14 to the oxidant gas discharge pipe 46 b. The oxidant exhaust gas is separated into a liquid water portion and a gas portion by being discharged into the gas-liquid separator 62. The gas portion is led out from the exhaust opening 68 to the exhaust pipe 70, boosted to the set pressure of the pressure regulating valve 72, and then discharged to the outside.

  The liquid water portion is stored in the gas-liquid separator 62, and a part thereof is supplied from the drain opening 64 through the water distribution pipe 66 to the water storage chamber 50 </ b> R in the water storage tank 50 from the liquid water supply port 54 a. In the water storage chamber 50R, excess liquid water is drained from the liquid water discharge port 54b to the drain pipe 74, joins the exhaust pipe 70, and is mixed with the gas component and discharged.

  Similarly, the fuel exhaust gas, which is hydrogen gas supplied to the anode electrode 30 and partially consumed, is discharged from the fuel gas outlet communication hole 44b of the fuel cell stack 14 to the fuel gas discharge pipe 78b. The fuel exhaust gas is sucked into the ejector 84 from the fuel gas discharge pipe 78b through the circulation passage 86, mixed with new hydrogen gas, and supplied to the fuel cell stack 14.

  In this case, in the first embodiment, the oxidant exhaust gas is introduced from the fuel cell stack 14 into the gas-liquid separator 62, whereby the water vapor separated from the oxidant exhaust gas is condensed and liquid water is generated. ing. The liquid water is introduced into the water storage tank 50 through the water distribution pipe 66 and stored in the water storage chamber 50R disposed on the ultrasonic transducer 56.

  Therefore, when the air supplied to the fuel cell stack 14 needs to be humidified, the ultrasonic transducer 56 is driven, for example, during low-load power generation, idling, or when a decrease in humidity is detected by impedance measurement. . For this reason, since the liquid water stored in the water storage chamber 50R is atomized, the air introduced into the water storage chamber 50R via the air compressor 48 is humidified. Therefore, the humidified air can be supplied to the fuel cell stack 14.

  Thus, in 1st Embodiment, the water storage tank 50 and the gas-liquid separator 62 are comprised separately. Accordingly, it is possible to satisfactorily suppress the air flowing through the water storage tank 50 from being discharged to the oxidant gas discharge pipe 46b by bypassing the fuel cell stack 14 with a simple and compact configuration.

  In addition, the water storage tank 50 is provided with an ultrasonic vibrator 56 for atomizing the liquid water in the water storage tank 50 to humidify the air. For this reason, the air which passes the inside of the water storage tank 50 can be humidified more reliably.

  Furthermore, it has the water distribution piping 66 which connects the water storage tank 50 and the gas-liquid separator 62, The orifice 76a is arrange | positioned at the said water distribution piping 66. FIG. Therefore, it is possible to reliably prevent the air introduced into the water storage tank 50 from flowing back to the gas-liquid separator 62. In addition, an orifice 76b is disposed in the drain pipe 74 connected to the liquid water discharge port 54b of the water storage tank 50. Thereby, it is possible to reliably prevent the air introduced into the water storage tank 50 from being discharged to the drain pipe 74.

  Furthermore, the drain opening 64 that discharges liquid water from the gas-liquid separator 62 to the water distribution pipe 66 has a distance h higher than the liquid water supply port 54 a that introduces the liquid water from the water distribution pipe 66 to the water storage tank 50. Are spaced apart. For this reason, the liquid water in the gas-liquid separator 62 can move to the gas-liquid separator 62 by its own weight, and the liquid water can be favorably transferred with a simple configuration.

  Further, the liquid water discharge port 54b is separated vertically upward from the liquid water supply port 54a, thereby setting the water level ws in the water storage tank 50 to a predetermined position, and the water storage amount in the water storage tank 50 is kept constant. Keep in quantity. Accordingly, the amount of water stored in the water storage tank 50 can be maintained to the minimum necessary, and the efficiency of atomization by the ultrasonic vibrator 56 can be easily achieved.

  Further, the ultrasonic transducer 56 is placed on the installation surface 60 via the rubber mount 58. Thereby, it becomes possible to suppress the vibration by the ultrasonic transducer | vibrator 56 being transmitted to the circumference | surroundings, and the influence by noise can be avoided.

  FIG. 2 is a schematic configuration explanatory diagram of a fuel cell system 100 according to the second embodiment of the present invention. Note that the same components as those of the fuel cell system 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell system 100 includes a single casing 102, and a water storage tank 104 and a gas-liquid separator 106 are formed in the casing 102. A wall plate 108 that partitions the water storage tank 104 and the gas-liquid separator 106 is disposed in the housing 102, and the water storage tank 104, the gas-liquid separator 106, and the like are disposed below the wall plate 108. The opening part (water distribution part) 110 which communicates is formed.

  A liquid water discharge port 54 is formed in the housing 102 at the lower side of the side surface of the water storage tank 104. The opening 110 is formed below the liquid water discharge port 54, that is, below the water level lower limit position w1 of the gas-liquid separator 106. An orifice 76 is disposed in the liquid water discharge port 54.

  The bottom surface 102 s of the housing 102 constitutes an inclined bottom surface 112, at least a part on the gas-liquid separator 106 side is disposed above the bottom surface of the water storage tank 104 and is inclined downward toward the water storage tank 104. .

  In the second embodiment configured as described above, the water storage tank 104 and the gas-liquid separator 106 are formed in the same casing 102. Moreover, the opening 110 that allows the water storage tank 104 and the gas-liquid separator 106 to communicate with each other is formed below the water level lower limit position w1 of the gas-liquid separator 106. For this reason, the number of parts can be easily reduced, and the entire fuel cell system 100 can be configured compactly.

  Further, at least a part of the bottom surface 102 s of the gas-liquid separator 106 is disposed above the bottom surface of the water storage tank 104 and constitutes an inclined bottom surface 112 that is inclined downward toward the water storage tank 104. Therefore, the liquid water in the gas-liquid separator 106 can smoothly flow to the water storage tank 104 under the guiding action of the inclined bottom surface 112 with a simple configuration.

DESCRIPTION OF SYMBOLS 10,100 ... Fuel cell system 12 ... Power generation cell 14 ... Fuel cell stack 16 ... Oxidant gas supply device 18 ... Fuel gas supply device 22 ... Electrolyte membrane and electrode structure 24, 26 ... Separator 28 ... Solid polymer electrolyte membrane 30 ... Anode electrode 32 ... Cathode electrode 34 ... Fuel gas flow path 36 ... Oxidant gas flow path 40a, 40b ... End plate 42a ... Oxidant gas inlet communication hole 42b ... Oxidant gas outlet communication hole 44a ... Fuel gas inlet communication hole 44b ... fuel gas outlet communication hole 46a ... oxidant gas supply pipe 46b ... oxidant gas discharge pipe 48 ... air compressors 50, 104 ... water storage tank 50R ... water storage chamber 52a ... oxidant gas inlet 52b ... oxidant gas outlet 54, 54b ... Liquid water discharge port 54a ... Liquid water supply port 56 ... Ultrasonic vibrator 58 ... Rubber mount 60 ... Installation surface 62, 10 ... gas-liquid separator 64 ... drain opening 66 ... water distribution pipe 68 ... exhaust opening 72 ... pressure regulating valves 76, 76a, 76b ... orifice 78a ... fuel gas supply pipe 78b ... fuel gas discharge pipe 80 ... hydrogen tank 102 ... housing Body 102s ... Bottom 108 ... Wall plate 110 ... Opening 112 ... Inclined bottom

Claims (6)

A fuel cell that generates electricity by an electrochemical reaction between a fuel gas and an oxidant gas;
An oxidant gas supply pipe for supplying the oxidant gas to the fuel cell;
An oxidant gas discharge pipe for discharging the oxidant gas from the fuel cell;
A fuel cell system comprising:
A water storage section disposed in the oxidant gas supply pipe;
A gas-liquid separator disposed in the oxidant gas discharge pipe;
With
A fuel cell system, wherein a water distribution unit is provided for circulating liquid water from the gas-liquid separation unit to the water storage unit.   2. The fuel cell system according to claim 1, wherein the water reservoir is provided with an ultrasonic vibrator for atomizing the liquid water in the water reservoir and humidifying the oxidant gas. Fuel cell system. 3. The fuel cell system according to claim 1, wherein the water distribution section includes a water distribution pipe that connects the water storage section and the gas-liquid separation section.
An orifice is disposed in the water distribution pipe.   4. The fuel cell system according to claim 3, wherein a drain opening that discharges the liquid water from the gas-liquid separator to the water distribution pipe is a water supply opening that introduces the liquid water from the water distribution pipe to the water reservoir. A fuel cell system, wherein the fuel cell system is disposed above. The fuel cell system according to claim 1 or 2, wherein the water storage part and the gas-liquid separation part are formed in the same casing.
The fuel cell system is characterized in that an opening for communicating the water storage part and the gas-liquid separation part is formed below a water level lower limit position of the gas-liquid separation part.   6. The fuel cell system according to claim 5, wherein at least a part of the bottom surface of the gas-liquid separation unit is disposed above the bottom surface of the water storage unit and is inclined downward toward the water storage unit. A fuel cell system comprising:

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