JP2005071730A - Air humidification device for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air humidification device for a fuel cell for making use of generated water which is generated by power generation of the fuel cell for humidifying reaction air, for suppressing the enlargement of the device and an increase in its weight by maintaining the constitution to humidify the reaction air simple, and for saving the consumption of power by making electrical equipment such as a valve or a pump unnecessary. <P>SOLUTION: There are provided an air filter 22a eliminating dust in the reaction air, and a water guiding pipe 84 in which while one end 84a connected to the fuel cell 12 (specifically, installed below a reaction air exhausting opening 80a of the fuel cell 12) and another end 84b is installed above the air filter 22a. At the same time, an air filter 22a is moisturized by having the generated water generated by the power generation of the fuel cell 12 dropped onto it through the water guiding pipe 84. Therefore, the reaction air fed to an air pole of the fuel cell 12 through the air filter 22a is humidified. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an air humidifier for a fuel cell.

  In the polymer electrolyte fuel cell, the power generation efficiency decreases when the water content of the electrolyte membrane decreases. Thus, many techniques have been proposed in which the reaction air supplied to the air electrode of the fuel cell is humidified to increase the water content of the electrolyte membrane and improve the power generation efficiency.

For the humidification of the reaction air, generated water generated by power generation of a fuel cell is widely used. In such a technique, generally, the generated water is stored in a water storage tank, and the stored generated water is supplied to a humidifier via a pump or a valve, so that the reaction air passing through the humidifier is humidified. (For example, refer to Patent Document 1).
JP-A-8-195209

  However, in the above-described conventional technology, since a pump and a valve for supplying the generated water to the humidifier are required, the configuration is complicated, leading to an increase in the size and weight of the device. was there. In addition, there is a problem that electric power is required to drive the pump and the valve.

  Accordingly, the object of the present invention is to solve the above-mentioned problems, simplify the configuration for humidifying the reaction air while using the generated water generated by the power generation of the fuel cell for humidification of the reaction air, and increase the size of the apparatus. An object of the present invention is to provide an air humidifier for a fuel cell that suppresses the increase in weight and weight, and eliminates the need for electric devices such as valves and pumps so that power is not consumed.

  In order to solve the above-mentioned object, according to claim 1, in an air humidifier of a fuel cell for humidifying reaction air supplied to an air electrode of the fuel cell, an air filter for removing dust from the reaction air; A water guide pipe having one end connected to the fuel cell and the other end arranged above the air filter, and the generated water generated by the power generation of the fuel cell through the water pipe The reaction air dropped into the air filter was allowed to contain water, and thus the reaction air supplied to the air electrode of the fuel cell through the air filter was humidified.

  Further, according to claim 2, a water storage tank is further disposed below the air filter, and generated water that is not absorbed by the air filter is stored in the water storage tank, and the air filter is stored in the water storage tank. A part of the air filter was accommodated, and thus a part of the air filter was immersed in the stored generated water.

  Further, in claim 3, a drain outlet is provided in a portion located at a predetermined height of the water storage tank so that a part of the air filter is immersed in the generated water stored up to the predetermined height. Configured.

  According to a fourth aspect of the present invention, the air filter is made of a hygroscopic material.

  According to a first aspect of the present invention, there is provided an air filter that removes dust from the reaction air, a water conduit that has one end connected to the fuel cell and the other end disposed above the air filter, and the fuel. The generated water generated by the power generation of the battery is dropped into the air filter via the water conduit and allowed to contain water, so that the reaction air supplied to the air electrode of the fuel cell through the air filter is humidified. Therefore, it is possible to simplify the configuration for humidifying the reaction air while using the generated water for humidification of the reaction air, thereby suppressing an increase in size and weight of the apparatus. Further, since no electrical equipment such as a valve or a pump is required, power is not consumed.

  Further, according to claim 2, a water storage tank is further disposed below the air filter, and generated water that is not absorbed by the air filter is stored in the water storage tank, and the air filter is stored in the water storage tank. In addition to the effect described in claim 1, the generated water is discharged (generated) from the fuel cell because a part of the air filter is accommodated, and thus a part of the air filter is immersed in the stored generated water. Even when it is not, the generated water stored in the water storage tank can be absorbed by the air filter so that it can be hydrated, so that the reaction air that passes through the air filter and is supplied to the air electrode of the fuel cell is humidified. be able to.

  Further, in claim 3, a drain outlet is provided in a portion located at a predetermined height of the water storage tank so that a part of the air filter is immersed in the generated water stored up to the predetermined height. In other words, since the surface area of the air filter immersed in the stored product water is set to a predetermined value or less, the air filter is added to the stored product water. Even if it is immersed, the flow rate of the reaction air passing through the air filter can be sufficiently ensured, so that supply of the reaction air to the air electrode is not hindered.

  Further, in claim 4, since the air filter is made of a material having hygroscopicity, in addition to the effects described in the previous claims, the water content and the water content speed of the air filter are set. Therefore, the reaction air that passes through the air filter and is supplied to the air electrode of the fuel cell can be humidified more effectively.

  The best mode for carrying out an air humidifier for a fuel cell according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a fuel cell air humidifier according to a first embodiment of the present invention as a part of a fuel cell unit.

  In FIG. 1, reference numeral 10 indicates a power generation unit including an air supply device for a fuel cell according to the first embodiment. The power generation unit 10 is formed by packaging elements necessary for power generation such as the fuel cell 12 and piping into a portable size.

  The fuel cell 12 (specifically, a stacked body (cell stack)) is formed by stacking a plurality of unit cells 14 (cells), specifically 70, and generates a rated output of 1.05 kW. The unit cell 14 is a known unit comprising an electrolyte membrane (solid polymer membrane), an air electrode (cathode electrode) and a fuel electrode (anode electrode) sandwiching the membrane, and a separator disposed outside each electrode. Since this is a polymer electrolyte fuel cell, detailed description is omitted.

  An air supply system 20 that supplies reaction air and cooling air to the fuel cell 12 is connected to the fuel cell 12. The air supply system 20 includes an air blower 22 that sucks air, a reaction air supply path 24 a that connects the air blower 22 to an air electrode (not shown) of the fuel cell 12, and a cooling air flow path ( And a cooling air supply path 24b connected to a not-shown). The air blower 22 includes an air filter 22a that removes dust from the sucked air (reaction air and cooling air), and a water storage tank 22b that is disposed below the air filter 22a (downward in the direction of gravity).

  A hydrogen gas supply system 30 that supplies hydrogen gas to the fuel cell 12 is further connected to the fuel cell 12. The hydrogen gas supply system 30 includes a hydrogen gas cylinder 32 filled with hydrogen at a high pressure, flow paths 34 a to 34 d (fuel supply paths) connecting the hydrogen gas cylinder 32 to the fuel cell 12, and each of which will be described later disposed in the middle thereof. It consists of elements.

  The hydrogen gas cylinder 32 is connected to a regulator 38 via a manual cylinder valve 36, and the regulator 38 is connected to an ejector 40 via a first flow path 34a. In the middle of the first flow path 34a, a main valve 42 (manual valve) is disposed, and a second flow path 34b that bypasses the main valve 42 is connected. A first electromagnetic valve 44 and a second electromagnetic valve 46 are disposed in the middle of the second flow path 34b.

  The ejector 40 is connected to each fuel electrode of the fuel cell 12 through the third flow path 34c and the fourth flow path 34d. The third flow path 34c is a supply-side flow path, and the fourth flow path 34d is a discharge-side flow path.

  Further, a nitrogen gas supply system 50 for supplying a purge gas (inert gas, for example, nitrogen gas) to the fuel cell 12 is connected downstream of the main valve 42 in the first flow path 34a. The nitrogen gas supply system 50 includes a nitrogen gas cylinder 52 filled with nitrogen at a high pressure, a fifth flow path 54 that connects the nitrogen gas cylinder 52 to the first flow path 34a, and each element that will be described later disposed in the middle of them. It consists of.

  The nitrogen gas cylinder 52 is connected to a regulator 58 via a manual cylinder valve 56, and the regulator 58 is connected to the first flow path 34 a via a fifth flow path 54. A third electromagnetic valve 60 is disposed in the middle of the fifth flow path 54.

  A purge gas discharge system 70 is connected to the ejector 40 described above. The purge gas discharge system 70 includes a purge gas discharge path 72 connected to the ejector 40 and a fourth electromagnetic valve 74 arranged in the middle of the purge gas discharge path 72.

  The fuel cell 12 includes a reaction air discharge port 80a connected to the discharge side of the air electrode and a cooling air discharge port 80b connected to the discharge side of the cooling air flow path. A receiving portion 82 for receiving the generated water discharged from the fuel cell 12 through the reaction air discharge port 80a is disposed below the reaction air discharge port 80a (downward in the direction of gravity). One end 84 a of the water conduit 84 is connected to the bottom surface of the receiving portion 82. Further, the other end 84b of the water conduit 84 is disposed above the air filter 22a (upward in the direction of gravity).

  An output circuit 100 is connected to the output terminal of the fuel cell 12. The output circuit 100 is connected to an external device (not shown) via the first DC-DC converter 102 and the relay 104, and is connected to the ECU 110 (electronic control unit) via the second DC-DC converter 106. . The ECU 110 is connected to an operation switch 112 that can be turned on and off from the outside and the relay 104 described above.

  Next, the power generation operation of the fuel cell 12 will be described based on the above configuration.

  The high-pressure hydrogen sealed in the hydrogen gas cylinder 32 is supplied to the regulator 38 when the cylinder valve 36 is manually opened. The hydrogen gas depressurized and regulated by the regulator 38 is supplied to the ejector 40 via the first flow path 34a when the main valve 42 is manually operated (opened), and further the third flow path 34c. To the fuel electrode of the fuel cell 12. The first to fourth electromagnetic valves 44, 46, 60, 74 shown in FIG. 1 prevent the hydrogen gas or nitrogen gas from flowing out when the fuel cell 12 is not in operation. It is assumed that all valves are closed at the end of operation. In other words, the first to fourth electromagnetic valves 44, 46, 60, and 74 are all normal / close type electromagnetic valves (electromagnetic valves that close when not energized and open when energized).

  In each unit cell 14 of the fuel cell 12, the hydrogen gas supplied to the fuel electrode causes an electrochemical reaction with the reaction air (oxygen) present in the air electrode, thereby starting power generation. Of the hydrogen gas supplied to the fuel electrode, unreacted gas that has not been subjected to an electrochemical reaction with air is recirculated to the ejector 40 via the fourth channel 34d, and the third channel 34c. Then, it is supplied again to the fuel electrode.

  When power generation of the fuel cell 12 is started, the electric power is converted into a DC voltage of an appropriate magnitude by the second DC-DC converter 106 provided in the output circuit 100, and then supplied to the ECU 110 as an operating power source. The

  The ECU 110 activated upon receiving the supply of electric power opens the first electromagnetic valve 44 and the second electromagnetic valve 46, and supplies hydrogen gas to the fuel electrode via the second flow path 34b. Further, the air blower 22 is operated to supply cooling air to the cooling air flow path, and supply reaction air to the air electrode.

  The reaction air that has passed through the air electrode and the cooling air that has been used for cooling each cell 14 are discharged from the inside of the fuel cell 12 through the reaction air discharge port 80a and the cooling air discharge port 80b, respectively.

  When the ECU 110 is activated and the first electromagnetic valve 44 and the second electromagnetic valve 46 are opened, there is no need to manually operate the main valve 42. For this reason, the ECU 110 appropriately notifies means (such as a voice or a display) that the ECU 110 is started after power generation of the fuel cell 12 is started, in other words, that the power supply to the external device is ready. (Not shown) to inform the operator.

  When the operation switch 112 is manually operated (turned on) by an operator who knows that the power supply to the external device is ready, the ECU 110 operates the relay 104 provided in the output circuit 100. The first DC-DC converter 102 is electrically connected to an external device. As a result, the electric power generated by the fuel cell 12 is converted into a direct current voltage having an appropriate magnitude by the first DC-DC converter 102 and then supplied to an external device via the relay 104.

  The ECU 110 also purges the fuel cell 12 by operating each electromagnetic valve based on the output of a voltage sensor (not shown). Specifically, when the detection value of the voltage sensor falls below a predetermined value, the first electromagnetic valve 44 and the second electromagnetic valve 46 arranged in the second flow path 34b are closed, and the fifth The third electromagnetic valve 60 arranged in the flow path 54 and the fourth electromagnetic valve 74 arranged in the purge gas discharge path 72 are opened.

  As a result, the supply of hydrogen gas is cut off, while the high-pressure nitrogen sealed in the nitrogen gas cylinder 52 is supplied to the regulator 58 through the cylinder valve 56, where it is depressurized and regulated, and then the fifth flow path 54. Then, it is supplied to the fuel electrode of the fuel cell 12 through the ejector 40 and the third flow path 34c. The cylinder valve 56 is assumed to be opened in advance by the operator when the operation of the fuel cell 12 is started.

  The nitrogen gas supplied to the fuel electrode is pushed out to the outside through the fourth flow path 34d, the ejector 40, and the purge gas discharge path 72 while pushing out the unreacted gas and generated water staying in the fuel electrode from the fuel cell 12. Discharged.

  Further, the generated water generated in the air electrode by the power generation by the fuel cell 12 is discharged from the air electrode through the reaction air discharge port 80a and dropped onto the receiving portion 82. The generated water dropped on the receiving portion 82 is dropped on the air filter 22a and the water storage tank 22b via the water conduit 84.

  FIG. 2 is a perspective view of the air blower 22. FIG. 3 is a side view of the air blower 22. In FIG. 3, the water storage tank 22b is shown in cross section. Hereinafter, the air blower 22 will be described in detail with reference to FIGS. 2 and 3.

  As shown in FIGS. 2 and 3, the air blower 22 includes a discharge port 22 c that discharges sucked air (reaction air and cooling air). The discharge port 22c is connected to the reaction air supply path 24a and the cooling air supply path 24b described above. The air blower 22 includes an electric motor 22d, and a fan (not shown) accommodated in the blower case 22e is fixed to the output shaft thereof.

  An air filter 22 a is attached to the air inlet of the air blower 22. The air filter 22a is manufactured from a hygroscopic material such as filter paper. Further, as described above, the other end 84b of the water guide tube 84 is disposed above the air filter 22a in the gravity direction, while the water storage tank 22b is disposed below the air filter 22a in the weight direction. The upper surface of the water storage tank 22b is opened, and a part (lower part) of the air filter 22a is accommodated in the water storage tank 22b.

  Further, a drain port 22b1 is formed on the side surface of the water storage tank 22b. Specifically, the drain port 22b1 is formed at a position located at a predetermined height h from the bottom surface of the water storage tank 22b.

  Next, the humidification operation of the reaction air will be described with reference to FIG. FIG. 4 is a schematic diagram showing the operation.

  As shown in FIG. 4, in this embodiment, the fuel cell 12, the receiving portion 82, one end 84 a and the other end 84 b of the water conduit 84, air, in the direction of gravity (indicated by an arrow g in the figure) from the top. The filter 22a and the water tank 22b are arranged in this order.

  Therefore, the generated water generated at the air electrode by the power generation of the fuel cell 12 is discharged from the reaction air discharge port 80a, then dropped onto the receiving portion 82, and further dropped onto the air filter 22a via the water conduit 84. Is done.

  The generated water dropped on the air filter 22a is absorbed by the air filter 22a, and thus the air filter 22a is water-containing. As a result, the air sucked by the air blower 22 is humidified by the water (product water) contained in the air filter 22a, and then supplied as reaction air to the air electrode of the fuel cell 12 via the reaction air supply path 24a. The

  Thus, in the air humidifier of the fuel cell according to the first embodiment of the present invention, the air filter 22a for removing the dust of the reaction air and the one end 84a are connected to the fuel cell 12 (specifically, Is disposed below the reaction air outlet 80a of the fuel cell 12), while the other end 84b includes a water conduit 84 disposed above the air filter 22a, and is generated by power generation of the fuel cell 12. Since the generated water is dripped into the air filter 22a via the water conduit 84 to contain water, the reaction air supplied to the air electrode of the fuel cell 12 through the air filter 22a is humidified. When the reaction air is humidified, it is not necessary to use a dedicated valve or pump. Therefore, the configuration for humidifying the reaction air can be simplified, and thus the size and weight of the apparatus can be increased. It is possible to suppress the increase of the. Further, since no electrical equipment such as a valve or a pump is required, power is not consumed.

  Further, since the air filter 22a is made of a material having a hygroscopic property, the water content and the water content speed of the air filter 22a can be improved, so that the reaction air can be humidified more effectively and the fuel cell. The power generation efficiency of 12 can be further improved.

  If the explanation of FIG. 4 is continued, the generated water that is not contained in the air filter 22a (it cannot be absorbed by the air filter 22a) is stored in a water storage tank 22b disposed below the air filter 22a.

  Here, since a part (lower part) of the air filter 22a is accommodated in the water storage tank 22b, a part of the air filter is immersed in the stored generated water. Therefore, even when the generated water is not discharged (generated) from the fuel cell 12, the generated water stored in the water storage tank 22b can be absorbed by the air filter 22a so that the water can be contained therein, and thus pass through the air filter 22a. The power generation efficiency of the fuel cell 12 can be improved by humidifying the reaction air.

  Moreover, since the above-mentioned discharge port 22b1 is formed in the side surface of the water tank 22b, the water level of generated water does not become more than the predetermined height h. In other words, the surface area of the air filter 22a immersed in the generated water can be set to a predetermined value or less. For this reason, even when the air filter 22a is immersed in the stored product water, the flow rate of the reaction air passing through the air filter 22a can be sufficiently secured, and the supply of the reaction air to the air electrode is hindered. There is nothing. In this embodiment, the predetermined height h is set so that 1/2 or more of the surface area of the air filter 22a always comes out of the surface of the water (not immersed in the generated water). .

  When the operation of the fuel cell 12 is started (when generated water is not generated and is not stored in the water storage tank 22b), water is applied to the air filter 22a from the outside (or the receiving portion 82). By supplying water to the water tank or by supplying water to the water storage tank 22b), the reaction air can be humidified from the initial stage of operation, so that the power generation efficiency immediately after the start of operation can be easily improved. Can do.

  As described above, in the first embodiment of the present invention, in the air humidifier of the fuel cell for humidifying the reaction air supplied to the air electrode of the fuel cell (12), the air for removing the dust of the reaction air is removed. A filter (22a) and a water conduit (84) having one end (84a) connected to the fuel cell (12) and the other end (84b) disposed above the air filter (22a) The generated water generated by the power generation of the fuel cell (12) is dropped into the air filter (22a) through the water conduit (84) to contain water, thereby passing through the air filter (22a) and The reaction air supplied to the air electrode of the fuel cell (12) was configured to be humidified.

  Furthermore, a water storage tank (22b) is disposed below the air filter, and the generated water that has not been absorbed by the air filter (22a) is stored in the water storage tank (22b), and the water storage tank (22b) has the A part of the air filter (22a) was accommodated, and thus a part of the air filter (22a) was soaked in the stored generated water.

  Further, a drain port (22b1) is provided at a portion of the water storage tank (22b) located at a predetermined height (h), so that a part of the air filter (22a) is stored up to the predetermined height (h). It was comprised so that it might be immersed in the produced | generated water.

  Further, the air filter (22a) is made of a hygroscopic material (for example, filter paper).

1 is a schematic diagram showing a fuel cell air humidifier according to a first embodiment of the present invention as part of a fuel cell unit; FIG. It is a perspective view of the air blower shown in FIG. It is a side view of the air blower shown in FIG. It is a schematic diagram explaining the humidification operation | movement of the reaction air in the apparatus shown in FIG.

Explanation of symbols

12 Fuel Cell 22a Air Filter 22b Water Reservoir 22b1 Drainage Port 84 Water Transfer Tube 84a One End of the Water Transfer Tube 84b Other End of the Water Transfer Tube

Claims (4)

  In an air humidifier for a fuel cell that humidifies reaction air supplied to an air electrode of the fuel cell, an air filter that removes dust from the reaction air and one end connected to the fuel cell, while the other end is the air A water conduit disposed above the filter, and water generated by the power generation of the fuel cell is dripped into the air filter via the water conduit, thereby passing through the air filter and passing through the air filter. An air humidifier for a fuel cell configured to humidify reaction air supplied to an air electrode of the fuel cell.   Furthermore, a water storage tank is disposed below the air filter, and the generated water that has not been absorbed by the air filter is stored in the water storage tank, and a part of the air filter is accommodated in the water storage tank. 2. The fuel cell air humidifier according to claim 1, wherein a part of the filter is soaked in the stored product water.   The drainage port is provided in a portion located at a predetermined height of the water tank, and thus a part of the air filter is configured to be immersed in the generated water stored up to the predetermined height. 3. An air humidifier for a fuel cell according to 2.   The fuel cell air humidifier according to any one of claims 1 to 3, wherein the air filter is made of a hygroscopic material.

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