JP2009123469A - Fuel cell power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell power generation system having high output stability.
A fuel cell power generation system for supplying power to an external load having a fuel cell in which at least a part of unit cells composed of a plurality of electrode / electrolyte integrated bodies is electrically connected in series or in parallel. The fuel cell has a positive electrode opening with an openable / closable door for introducing oxygen in the air into the positive electrode diffusion layer, and a ventilation path connecting the hydrogen flow path in the fuel cell and the outside of the fuel cell. And a backflow preventing means for opening the flow path only in the direction of exhausting from the hydrogen flow path in the fuel cell to the outside of the fuel cell, and the hydrogen flow path in the fuel cell from the outside of the fuel cell. This is a fuel cell power generation system in which at least one of the backflow prevention means that opens the flow path only in the direction in which the outside air flows is installed.
[Selection] Figure 6

Description

  The present invention relates to a fuel cell power generation system using hydrogen as a fuel.

In recent years, especially with the increase in functionality of portable devices, there is a demand for further reduction in size and capacity of batteries used for the power supply of such portable devices. In view of these demands, it is necessary to improve the energy density of the battery, and in addition to the problem of energy and CO ₂ reduction, the fuel cell is focused on as an alternative to the conventionally used lithium ion secondary battery. Has been.

  The fuel cell can be used continuously if fuel and oxygen are supplied. For example, a polymer electrolyte membrane fuel cell (PEMFC) is a positive electrode (cathode) that reduces oxygen in the air, a negative electrode (anode) that oxidizes hydrogen, and between these positive and negative electrodes. A unit cell that is an electrode / electrolyte integrated body (MEA) composed of a solid electrolyte membrane disposed on the substrate.

  By the way, as a problem for the practical application of the fuel cell, there is suppression of abnormal pressure fluctuation in the fuel cell during the fuel cell operation. As described above, the fuel cell takes in gas such as air (oxygen) and hydrogen to generate power, but when these gases are taken in excessively, the pressure inside the fuel cell rises, while the fuel cell is operated. Sometimes, when the gas consumption rate by power generation becomes faster than the gas supply rate, the pressure inside the fuel cell decreases. There is a risk that the fuel cell may be damaged by such abnormal pressure fluctuations during operation of the fuel cell.

  As a means for suppressing the abnormal pressure fluctuation in the fuel cell as described above, it is conceivable to provide a ventilation path that connects the inside and the outside of the fuel cell. When air enters the negative electrode side, there is a risk that the output stability may be impaired, for example, the voltage drops.

  For example, in Patent Document 1, oxygen supply pressure to the positive electrode and hydrogen supply pressure to the negative electrode are measured, and when one of the supply pressures is high, the gas having the higher supply pressure is introduced into the fuel cell. There has been proposed a method for preventing the fuel cell from being damaged by exhausting through the bypass without increasing the internal pressure difference between the positive electrode and the negative electrode. Furthermore, in the fuel cell of Patent Document 1, a backflow prevention valve is installed in the exhaust path of the positive electrode and the negative electrode, and when the exhaust pressure from the positive electrode is larger than the supply pressure of oxygen to the positive electrode, and the supply pressure of hydrogen to the negative electrode When the exhaust pressure from the negative electrode is higher than that, the outside air is prevented from flowing back into the positive electrode or the negative electrode, so that normal power generation can be maintained.

  Further, as another problem for the practical application of the fuel cell (PEMFC), there is a reduction in output reduction accompanying drying of the MEA. In PEMFC, it is preferable that the MEA (solid electrolyte membrane) is moistened to some extent in order to maintain a good output.

The following reactions occur in the negative and positive electrodes of PEMFC.
Negative electrode: H ₂ → 2H ⁺ + 2e ⁻
The positive ^{_{electrode: 1 / 2O 2 + 2H +}} + 2e - → H 2 O

  The entropy loss (TΔS = −48.7 kJ / mol) determined by the temperature T of the heat of formation (ΔH = −285.8 kJ / mol) when hydrogen and oxygen in the above reaction formula become water is exothermic due to the reaction. The quantity Q means that the output reaction of PEMFC is an exothermic reaction. In other words, as the output reaction of PEMFC progresses, hydrogen ions and some water molecules are combined, and when hydrogen ions move with the water molecules and water is generated on the positive electrode side, the water in the MEA solid electrolyte membrane evaporates. Battery characteristics may be deteriorated. Therefore, in PEMFC, it is common to use humidified hydrogen as the fuel to be supplied.

  However, depending on the operating environment of the PEMFC, the water generated by the reaction or the water in the supplied hydrogen may evaporate, and the MEA may dry and the battery performance may deteriorate, which may impair the output stability. There is. This is particularly problematic in a naturally aspirated fuel cell power generation system that does not have an auxiliary device such as a pump for sending air into the fuel cell.

  For this reason, a technique for appropriately maintaining the wet state of the MEA in a naturally aspirated fuel cell has also been proposed. For example, in Patent Document 2, in a naturally aspirated fuel cell, an openable / closable door is disposed at the positive air intake port, so that the solid electrolyte membrane is kept in an appropriate state even when the outside air is in a dry state. A technique that can be maintained is disclosed.

JP 2007-80721 A Japanese Patent Laid-Open No. 2005-228687

  However, in the technique described in Patent Document 1, it is difficult to avoid a decrease in output due to drying of the MEA because the wet state of the MEA cannot be maintained in an appropriate state.

  On the other hand, a door that can be opened and closed as disclosed in Patent Document 2 is arranged at the air intake port of the fuel cell, and the opening of the air intake port is appropriately adjusted according to the external environment and the situation inside the fuel cell. By maintaining the wet state of the solid electrolyte membrane in an appropriate state, the proton conductivity in the MEA is kept good, and the increase in internal resistance during the next start-up and operation of the fuel cell is suppressed, thereby stabilizing the output. There is a possibility that can be increased.

  However, in the above technique, even if the solid electrolyte membrane is kept wet by opening and closing the door, unnecessary outside air flows into the negative electrode side of the fuel cell due to fluctuations in the pressure of the fuel supply, etc., and hydrogen air (oxygen) The deterioration of output stability due to mixing cannot be suppressed.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a fuel cell power generation system having high output stability.

  The fuel cell power generation system of the present invention that has achieved the above object includes a positive electrode having a positive electrode diffusion layer and a positive electrode catalyst layer for reducing oxygen, a negative electrode having a negative electrode diffusion layer and a negative electrode catalyst layer and oxidizing fuel, A plurality of unit cells each having a solid electrolyte membrane disposed between the positive electrode and the negative electrode, and a hydrogen flow path for supplying hydrogen to each of the plurality of unit cells, and the plurality of unit cells. A fuel cell power generation system for supplying power to an external load having a fuel cell in which at least a part of the fuel cell is electrically connected in series or in parallel, wherein the fuel cell includes an openable / closable door In addition, it has a positive electrode opening for introducing oxygen in the air into the positive electrode diffusion layer, and a ventilation path that connects the hydrogen flow path in the fuel cell and the outside of the fuel cell, Hydrogen in the fuel cell Backflow prevention means for opening the flow path only in the direction of exhausting the fuel cell from the road to the outside of the fuel cell, and backflow prevention for opening the flow path only in the direction of outside air flowing from the outside of the fuel cell to the hydrogen flow path in the fuel cell At least one of the means is installed.

  The fuel cell power generation system of the present invention has a door capable of opening and closing the air in the positive electrode diffusion layer with oxygen in the air at the positive electrode opening, and the degree of opening of the positive electrode opening can be adjusted by the door. Therefore, for example, when operating under dry outdoor air conditions, the solid electrolyte membrane tends to dry out due to the ingress of dry air into the fuel cell, and the output tends to decrease. By making the opening degree of the portion relatively small, drying of the solid electrolyte membrane can be suppressed, and a decrease in output due to this can be suppressed. Also, for example, when operating a fuel cell at high output, the solid electrolyte membrane is dried by the heat generated in the unit cell body due to long-term operation, and the output tends to decrease. By increasing the degree, drying of the solid electrolyte membrane can be suppressed, and a decrease in output due to this can be suppressed. Thus, in the fuel cell power generation system of the present invention, the degree of opening of the positive electrode opening can be adjusted according to the situation by the door, so that drying of the solid electrolyte membrane can be suppressed and output can be stabilized. .

  In addition, the fuel cell power generation system of the present invention has a ventilation path provided with backflow prevention means in the fuel cell, and can suppress abnormal pressure fluctuations in the fuel cell during fuel cell operation. . That is, when the backflow prevention means opens the flow path only in the direction of exhausting from the hydrogen flow path in the fuel cell to the outside of the fuel cell, the gas in the fuel cell when the pressure in the fuel cell rises abnormally Can be exhausted. Also, in the case where the backflow prevention means opens the flow path only in the direction in which the outside air flows from the outside of the fuel cell into the hydrogen flow path in the fuel cell, the outside air is removed from the fuel cell when the pressure in the fuel cell decreases. Can be imported. Therefore, in the fuel cell power generation system of the present invention, it is possible to suppress the output decrease that may be caused by the pressure fluctuation in the fuel cell and to stabilize the output.

  Moreover, in the fuel cell power generation system of the present invention, it is possible to prevent the fuel cell from being damaged due to such pressure fluctuations and to ensure safety with an extremely simple device configuration such as a ventilation path provided with the backflow prevention means. In particular, when the backflow prevention means opens the flow channel only in the direction of exhausting from the hydrogen flow channel in the fuel cell to the outside of the fuel cell, unnecessary outside air flows into the fuel cell and It is possible to prevent deterioration of the unit cell and a decrease in output due to mixing with air (oxygen).

  According to the present invention, a fuel cell power generation system with good output stability can be provided. The fuel cell power generation system of the present invention can prevent damage due to abnormal pressure fluctuations in the fuel cell.

  FIG. 1 schematically shows an example of a fuel cell according to the fuel cell power generation system of the present invention. The fuel cell 1 has a plurality of (three) unit cells 100 electrically connected in series. On the positive electrode side, a positive electrode opening 201 for taking in air (oxygen) and introducing it into the positive electrode of the unit cell 100, and an open / close door for adjusting the opening degree of the positive electrode opening 201 (openable / closable door) ) 200 is provided. The door 200 shown in FIG. 1 is a slide type (when the degree of opening of the positive electrode opening 201 is reduced, it is slid in the direction of the arrow in the figure), and the fuel cell is more open than the opening end of the positive electrode opening 201. 1 is installed inside.

  In the fuel cell power generation system of the present invention, the opening degree of the positive electrode opening can be adjusted by controlling the opening and closing of the open / close door provided in the positive electrode opening.

  An example of a drive unit for moving the opening / closing door as shown in FIG. 1 will be described with reference to FIG. 2 includes an opening / closing door 200, a pin 202, a wire 203, a motor 204, and a rail 205. Moreover, the opening / closing door 200 and the pin 202 are integrated, and the wire 203 and the pin 202 are connected on one side (front side in FIG. 2).

  For example, when the motor 204 is rotated counterclockwise for a certain time to wind the wire 203, the open / close door 200 connected to the wire 203 via the pin 202 is opened in synchronization with the movement of the wire 203. Operates in the direction that the part closes. On the other hand, by rotating the motor 204 clockwise for a certain time, the open / close door 200 operates in a direction to open the positive electrode opening.

  With the mechanism shown in FIG. 2, since the front and rear pins 202 in the drawing are fitted in the rail 205, the open / close door 200 can be slid without difficulty. Therefore, the opening degree of the positive electrode opening 201 can be adjusted by adjusting the driving time of the motor 204 to control the opening / closing of the door 200.

  FIG. 3 schematically shows an example of a fuel cell having many positive electrode openings. In the fuel cell according to the fuel cell power generation system of the present invention, as shown in FIG. 3, a plate-shaped opening / closing door 206 in which a plurality of openings 201a are formed in advance can be used. That is, for example, in the fuel cell 1 shown in FIG. 3, the plate-shaped opening / closing door 206 is formed with an opening 201 a having the same size as the positive electrode opening 201, by half of the positive electrode opening 201. And, for example, by positioning the open / close door 206 so that all of the openings 201a of the plate-shaped open / close door 206 open the positive electrode opening 201, the opening degree of the positive electrode opening 201 can be 50%, For example, as shown in FIG. 3, the opening degree of the positive electrode opening 201 can be adjusted to 100% by positioning the open / close door 206 so that all of the positive electrode opening 201 opens. As described above, when the configuration shown in FIG. 3 is adopted, a mechanism that is relatively simpler than that in which a sliding door is separately installed in each positive electrode opening 201 can be provided.

  FIG. 4 schematically shows another example of the fuel cell according to the fuel cell power generation system of the present invention. A fuel cell 1 shown in FIG. 4 has a hinged door 200. The opening / closing door 200 is slightly larger than each positive electrode opening 201 so that the area of the open / close door 200 can be completely closed, and on the long side of one side of the positive electrode opening 201 of the fuel cell 1. The doors are connected via a fulcrum 209, and further connected to the other opening / closing doors 200 and 200 by two connectors 207 and 207. In addition, one of the open / close doors 200 is connected by a fulcrum 209 and a regulator 208 that is driven up and down on the short side.

  An example of a drive unit for moving the opening / closing door in the case of a hinged door type as shown in FIG. 4 will be described with reference to FIG. In FIG. 5, the side surface of the hinged door 200 and the internal structure of the driving device 220 for driving the door 200 are shown. The hinged door shown in FIG. 5 includes an opening / closing door 200, a coupler 207, a regulator 208, a fulcrum 209, and a driving device 220. The driving device 220 includes a gear 210, a gear 211, a ball screw 212, and a motor 204, and the tip of the adjuster 208 is inserted into the drive device 220, and the tip of the adjuster 208 and the gear 210 is connected. The adjuster 208 is inserted into a through hole (not shown) provided in the exterior of the fuel cell 1 and is connected to the gear 210 of the driving device 220. The fuel cell 1 is disposed around the through hole. It is preferable that a seal is provided so that internal hydrogen or the like does not leak.

  For example, when operating in the direction to open the opening / closing door 200, the motor 204 is rotated for a certain period of time, and the adjuster 208 is driven upward in the figure via the ball screw 212, the gear 211 and the gear 210. As a result, the opening / closing door 200 (the rightmost opening / closing door in the figure) connected to the adjuster 208 via the fulcrum 209 operates in the direction of opening the positive electrode opening, and the opening / closing door 200 and the coupler 207 are connected. The other open / close doors 200 and 200 connected via the same also operate in the direction of opening the positive electrode opening. On the contrary, by rotating the motor 204 for a certain period of time so that the adjuster 208 is driven downward in the figure, each of the open / close doors 200, 200, 200 operates in the direction of closing the positive electrode opening. Therefore, the opening / closing of the hinged door 200 can be controlled by adjusting the driving time of the motor 204, and thereby the opening degree of the positive electrode opening can be adjusted.

  The material of the open / close door is not particularly limited as long as it has airtightness and corrosion resistance. For example, polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoro Known heat-resistant fluororesins such as ethylene-hexafluoropropylene copolymer (FEP) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA); Known polymers such as polypropylene (PP) and polyacetal resin; etc. In addition, a corrosion-resistant thin metal plate such as stainless steel (SUS) or Ti can also be used. The open / close door may be composed of only one of the constituent materials exemplified above, or may be composed of two or more in combination.

  FIG. 6 shows an example of the configuration of the fuel cell power generation system of the present invention. The fuel cell power generation system shown in FIG. 6 has a plurality of unit cells 100 electrically connected in series, and controls the degree of opening of the positive electrode opening for introducing air into the positive electrode of each unit cell 100. A fuel cell 1 having an openable / closable door 200, a hydrogen supply device 2 for supplying hydrogen to the fuel cell 1, and a hydrogen removing means provided in a hydrogen flow path 7 between the hydrogen supply device 2 and the fuel cell 1. A hydrogen removing device 3 is provided. Further, the fuel cell 1 according to the fuel cell power generation system shown in FIG. 6 is connected to an external load 4 (such as an electronic device to which the fuel cell power generation system is applied) via a switch 11.

  Hydrogen generated by the hydrogen supply device 2 is supplied to the negative electrode of the unit cell 100 constituting the fuel cell 1 through the hydrogen flow path 7. Reference numeral 8 denotes a ventilation path that connects the hydrogen flow path in the fuel cell 1 to the outside of the fuel cell 1. 9a and 9b are backflow prevention means, 9a can open the flow path only in the direction of exhausting from the hydrogen flow path in the fuel cell 1 to the outside of the fuel cell 1, and 9b is inside the fuel cell 1 from the outside of the fuel cell 1. The channel can be opened only in the direction in which the outside air flows into the hydrogen channel.

  Further, in the fuel cell power generation system shown in FIG. 6, a stop valve 5 is provided between the hydrogen supply device 2 and the hydrogen removal device 3, and when the fuel cell power generation system is stopped, the stop valve 5 is closed. Thus, hydrogen is not supplied to the fuel cell 1 thereafter. However, the stop valve 5 is not essential in the fuel cell power generation system of the present invention, and can be omitted as appropriate.

  As shown in FIG. 6, the fuel cell 1 can be provided with detection means 6 for controlling the door 200. Then, a control means 10 that is an information processing apparatus such as a microcomputer is provided, and a detection signal from the detection means 6 is sent to the control means 10 as indicated by an arrow in FIG. Thus, the operation of the open / close door 200 can be controlled by the control means 10. Similarly, as indicated by arrows in FIG. 6, the control means 10 may also control the stop valve 5 and the electric output to the external load 4 connected to the fuel cell 1. it can.

  In the fuel cell power generation system shown in FIG. 6, the operation of the open / close door 200 provided in the positive electrode opening of the fuel cell 1 can be controlled by a control signal (arrow in FIG. 6) from the control means 10. It is also possible to operate the opening / closing door 200 by a manual method regardless of the control signal of the means 10, or manually based on the detection result of the detection means 6 without providing the control means 10. The open / close door 200 may be operated by the method described above. When the control means 10 is omitted, there is an advantage that the fuel cell power generation system can be easily reduced in size and weight.

  As described above, the wet state of the appropriate solid electrolyte membrane is favorably maintained by controlling the opening / closing door 200 based on parameters such as the temperature during power generation of the fuel cell 1 to adjust the opening degree of the positive electrode opening. And the output can be stabilized.

  Further, in the fuel cell 1 during operation, when the pressure in the hydrogen flow path 7 or the ventilation path 8 becomes abnormally high, the backflow prevention means 9a is activated to discharge the hydrogen out of the fuel cell 1, and the hydrogen flow When the pressure in the passage 7 or the ventilation path 8 is abnormally reduced, outside air can be quickly taken into the fuel cell 1 by the backflow prevention means 9b, and abnormal pressure fluctuations or ventilation in the fuel cell 1 can be caused by these actions. It is possible to stabilize the output by suppressing the inflow of air to the negative electrode side of the fuel cell 1 due to the inflow of unnecessary outside air into the path 8, and further, damage to the fuel cell 1 and hydrogen from the fuel cell 1. It is also possible to suppress leakage.

  In the fuel cell power generation system of the present invention, the flow path is opened only in the direction of exhausting from the hydrogen flow path in the fuel cell to the outside of the fuel cell in accordance with the pressure fluctuation to be avoided (abnormal pressure increase or abnormal pressure reduction). Either one of the backflow prevention means and the backflow prevention means that opens the flow path only in the direction in which the outside air flows into the hydrogen flow path in the fuel cell from the outside of the fuel cell may be installed. In such a case, problems due to abnormal pressure fluctuations in the fuel cell can be avoided more reliably.

  The backflow prevention means that can be used in the fuel cell power generation system of the present invention is not particularly limited as long as it has airtightness and has a one-way vent hole function, but it is a lift type having a valve body that moves in parallel. Directional check valves such as check valves, swing-type check valves with hinged valve bodies, ball valves with spherical valve bodies; constant pressures such as pressure reducing valves, safety valves, and relief valves (check valves) A pressure control valve having a structure in which gas from the valve is naturally discharged at a fluctuation or more is preferably used. Further, by making the above illustrated valve an electromagnetic valve that can be electrically driven, the exhaust of gas from the fuel cell and the intake of outside air into the fuel cell can be electrically controlled.

  A suitable value of the opening start operating pressure in the backflow preventing means may vary depending on the size of the fuel cell power generation system, but is preferably, for example, 0.5 MPa or less in gauge pressure. The fuel cell power generation system also has a backflow prevention means (9a in FIG. 6) that opens the flow path only in the direction of exhausting from the hydrogen flow path in the fuel cell to the outside of the fuel cell, and hydrogen in the fuel cell from the outside of the fuel cell. Differential pressure value of the backflow prevention means (opening start operating pressure of the backflow prevention means 9a) when both of the backflow prevention means (9b in FIG. 6) that open the flow path only in the direction in which the outside air flows into the flow path are provided. And a suitable value of the opening start operating pressure of the backflow prevention means 9b) may vary depending on the size of the fuel cell power generation system, but is preferably 0 to 0.1 MPa. In addition, when making a difference between the backflow preventing means 9a, the opening start operating pressure, and the opening start operating pressure of the backflow preventing means 9b, a reduction in output due to outside air being taken into the fuel cell during operation of the fuel cell is prevented. Therefore, it is preferable that the opening start operating pressure of the backflow preventing means 9b is higher than the opening start operating pressure of the backflow preventing means 9a.

  The constituent material of the backflow preventing means is not particularly limited as long as it has airtightness and corrosion resistance. For example, known heat resistant fluororesins such as PTFE, ETFE, FEP, PFA; PP, polyacetal resin, etc. And known polymers are suitable.

  Further, in the fuel cell power generation system of the present invention, it is preferable to install the hydrogen removal device 3 between the fuel cell 1 and the hydrogen supply device 2 as shown in FIG. The hydrogen removal device 3 is operated when the external load 4 is turned off, that is, when the operation of the fuel cell 1 is stopped. As a result, when hydrogen supply from the hydrogen supply device 2 continues to the fuel cell 1 or when hydrogen leaks into the fuel cell 1 even if the hydrogen supply is stopped by the stop valve 5, hydrogen removal is performed. The device 3 can consume hydrogen toward the fuel cell 1. As a result, hydrogen supply into the fuel cell 1 is not performed or the supply amount is greatly reduced, so that deterioration of the unit cell in the fuel cell 1 due to such hydrogen can be suppressed, and the fuel The life of the battery 1 can be extended.

  FIG. 7 shows another configuration example of the fuel cell power generation system of the present invention. In the fuel cell power generation system of FIG. 7, in each unit cell 100 of the fuel cell 1, the positive electrode and the negative electrode are connected by a lead body or the like via a resistor 12 and a switch so as to be conductive. The fuel cell is configured to be usable as a means for consuming hydrogen remaining in the fuel cell, that is, as a hydrogen removing device.

  In the fuel cell according to the fuel cell power generation system, even after the operation is stopped, hydrogen remains in the fuel cell, which may deteriorate the positive electrode and the negative electrode of the unit cell and impair the life of the fuel cell. is there. However, in the fuel cell power generation system shown in FIG. 7, when the external load 4 is turned off and the operation of the fuel cell 1 is stopped, each unit cell 100 is used, for example, as shown in FIG. The hydrogen remaining in the fuel cell 1 can be consumed by making the positive electrode and the negative electrode conductive by turning on a switch provided on the lead body connecting between the positive electrode and the negative electrode. As described above, the fuel cell power generation system shown in FIG. 7 further includes means for consuming hydrogen remaining in the fuel cell 1 in addition to the hydrogen removal device 3, so that it remains in the fuel cell 1. Deterioration of the fuel cell 1 due to hydrogen can be suppressed, and the life of the fuel cell 1 can be further extended.

  In the fuel cell power generation system of FIG. 7, the positive electrode and the negative electrode of each unit cell 100 of the fuel cell 1 are connected via a resistor 12. For example, the resistor 12 is related to the fuel cell power generation system. After stopping the fuel cell 1, it is sufficient to use one having a resistance value such that the time required for the voltage between the positive electrode and the negative electrode of the unit cell 100 to be 0.1 V or less is within 1 minute, without using the resistance. It is also possible to connect to the terminal with a lead body or the like only through a switch so that conduction is possible. In addition, a power storage device such as a secondary battery may be provided to guide the output of the unit cell 100 to the power storage device.

  Although FIG. 7 shows an example in which all unit cells 100 are configured to be usable as hydrogen removing devices, only some of the unit cells 100 in the fuel cell 1 can be utilized as hydrogen removing devices. You may comprise. By configuring at least one unit cell 100 in the fuel cell 1 to be usable as a hydrogen removing device, it is possible to prevent deterioration of each unit cell 100 in the fuel cell 1 due to hydrogen.

  When only a part of the unit cells 100 in the fuel cell 1 can be used as a hydrogen removal device, the unit cells 100 closer to the hydrogen supply device 2 can be used as a hydrogen removal device. It is preferable to configure as described above. As described above, deterioration of the unit cell 100 due to hydrogen after the fuel cell 1 is stopped may be caused by hydrogen continuously supplied from the hydrogen supply device 2 in addition to hydrogen remaining in the fuel cell 1. For this reason, the unit cell 100 arranged at a position closer to the hydrogen supply device 2 (a position closer to the hydrogen inlet of the fuel cell 1, preferably a position closest to the hydrogen inlet) is used as a hydrogen removal device, so that the fuel cell This is because it is easier to prevent the deterioration of each unit cell 100 by quickly consuming the hydrogen that has entered the inside.

  In addition, the unit cell 100 configured to be usable as a hydrogen removal device is not connected to other unit cells 100 (unit cells 100 not configured to be usable as a hydrogen removal device), but only as a hydrogen removal device. It can also function.

  Furthermore, in FIG. 7, the unit cell 100 in the fuel cell 1 is configured to be usable as a hydrogen removal device, and the hydrogen removal device 3 is disposed between the fuel cell 1 and the hydrogen supply device 2. As shown, when at least one of the unit cells 100 in the fuel cell 1 is configured to be usable as a hydrogen removal device, the hydrogen removal device 3 between the fuel cell 1 and the hydrogen supply device 2 is It can also be omitted, thereby making the fuel cell power generation system more compact. On the other hand, as shown in FIG. 7, at least one of the unit cells 100 in the fuel cell 1 is configured to be usable as a hydrogen removal device, and hydrogen is removed between the fuel cell 1 and the hydrogen supply device 2. When the device 3 is arranged, the fuel cell 1 can have a longer life as described above.

  In the fuel cell power generation system of FIG. 7, the external load 4 is turned off at the time of stoppage, and in each unit cell 100, the switch provided on the lead body that connects between the positive electrode and the negative electrode is turned on. Is consumed, the pressure in the fuel cell 1 decreases. In this case, the backflow prevention means 9b is automatically opened, and outside air is taken into the fuel cell 1 to prevent a decrease in internal pressure, so that the destruction of the fuel cell 1 can be suppressed.

  Further, FIG. 8 shows another configuration example of the fuel cell power generation system of the present invention. In the fuel cell power generation system shown in FIG. 8, the fuel cell 1 has two ventilation paths 8a and 8b. The backflow prevention means 9a is installed in the ventilation path 8a, and the backflow prevention means 9b is installed in the ventilation path 8b. ing. As in the fuel cell power generation system shown in FIGS. 6 and 7, when the ventilation path 8 is a T-shaped branch, and the backflow prevention means 9a and 9b are installed in each of the branched paths, the backflow prevention means 9a uses the fuel cell. When exhausting from the hydrogen flow path in the fuel cell 1 to the outside of the fuel cell 1, water or the like generated in the fuel cell 1 enters the ventilation path 8, and the water prevents the backflow prevention means 9b from clogging. May decrease. However, as in the fuel cell power generation system shown in FIG. 8, by separating the ventilation path for installing the backflow prevention means 9a and the ventilation path for installing the backflow prevention means 9b, the hydrogen flow path in the fuel cell 1 can be separated. It is possible to prevent clogging of the backflow prevention means 9b due to water that has entered the ventilation path when exhausting the fuel cell 1 to the outside. On the other hand, as in the fuel cell power generation system shown in FIGS. 6 and 7, when the ventilation path 8 is a T-shaped branch and the backflow prevention means 9a and 9b are installed in each of the branched paths, the system is more There is an advantage that it is easy to downsize.

  FIG. 9 shows another configuration example of the fuel cell power generation system of the present invention. In the fuel cell power generation system shown in FIG. 9, the fuel cell 1 includes a plurality of ventilation paths 8a, a backflow prevention means 9a installed therein, a ventilation paths 9b, and a backflow prevention means 8b installed therein. I have one. According to the fuel cell power generation system of FIG. 9, it becomes possible to respond more rapidly to sudden pressure fluctuations in the fuel cell 1 than the fuel cell power generation systems shown in FIGS.

  As described above, in the fuel cell power generation system, the backflow prevention means that opens the flow path only in the direction of exhausting from the ventilation path in the fuel cell to the outside of the fuel cell, and outside air from the outside of the fuel cell to the ventilation path in the fuel cell. Either one of the backflow prevention means that opens the flow path only in the inflow direction may be installed. However, it is preferable that both are installed, and as shown in FIG. Backflow prevention means for opening the flow path only in the direction of exhausting from the air flow path to the outside of the fuel cell and backflow prevention means for opening the flow path only in the direction of outside air flowing from the outside of the fuel cell to the ventilation flow path in the fuel cell, A plurality of them (two, three, four, etc.) may be installed. Particularly in the case of a large fuel cell power generation system, as shown in FIG.

  FIG. 10 is a schematic diagram showing a cross-section of the main part of an example of the fuel cell 1 in the fuel cell power generation system according to the present embodiment. However, in FIG. 10, in order to facilitate understanding of each component, a hatched line indicating a cross section is omitted for some components. 10 shows a state in which three unit cells 100 are combined to form one fuel cell 1, this is just an example, and the number of unit cells in the fuel cell as one unit is shown. The number of fuel cells is not limited to three, and a single unit fuel cell formed of a plurality of unit cells may be connected to form a single fuel cell.

  In the fuel cell 1 shown in FIG. 10, a positive electrode composed of a positive electrode diffusion layer 101 and a positive electrode catalyst layer 102, a solid electrolyte membrane 103, and a negative electrode composed of a negative electrode diffusion layer 105 and a negative electrode catalyst layer 104 are sequentially laminated to form a unit cell. 100, and three unit cells 100 are arranged in a plane.

  On the positive electrode side of each unit cell 100, positive electrode current collecting plates 114, 116a, 116b, a positive electrode insulating plate 112, an open / close door 200, and a positive electrode panel plate 110 are sequentially arranged. Further, negative electrode current collecting plates 115, 117 a and 117 b, a negative electrode insulating plate 113, and a negative electrode panel plate 111 are sequentially arranged on the negative electrode side of each unit cell 100. The three unit cells 100 are sandwiched and integrated with the positive panel plate 110 and the negative panel plate 111. Although not shown in FIG. 10, adjacent unit cells 100 are connected in series by electrical connection between the positive electrode current collector plates 114, 116a, 116b and the negative electrode current collector plates 115, 117a, 117b. Yes.

  The positive electrode current collecting plates 114, 116a, 116b, the positive electrode insulating plate 112, and the positive electrode panel plate 110 are provided with a plurality of oxygen introduction holes for introducing oxygen in the air outside the fuel cell 1 to the positive electrode. Then, the positive diffusion of the unit cell 100 from the outer surface of the positive panel plate 110 by the oxygen introduction hole of the positive current collector plates 114, 116 a, 116 b, the oxygen introduction hole of the positive electrode insulating plate 112, and the oxygen introduction hole of the positive panel plate 110. A plurality of positive electrode openings 201 reaching the layer 101 are formed. The open / close door 200 is a slide type, and the degree of opening of the positive electrode opening 201 can be adjusted by sliding it to the left and right in the drawing. FIG. 10 shows a state in which a part (50% in FIG. 10) of the positive electrode opening 201 is blocked by the open / close door 200, and is open to the positive electrode diffusion layer 101 without being blocked by the open / close door 200. Only in the positive electrode opening 201, oxygen in the air is supplied to the positive electrode diffusion layer 101 by diffusion.

  Further, in the fuel cell 1 shown in FIG. 10, the negative electrode current collecting plates 115, 117a, 117b, the negative electrode insulating plate 113, and the negative electrode panel plate 111 have hydrogen introduction holes for introducing hydrogen in the fuel tank portion 119 into the negative electrode. A plurality are provided. A unit cell is formed from the surface of the negative electrode panel plate 111 on the fuel tank portion 119 side by the hydrogen introduction holes of the negative electrode current collecting plates 115, 117a, 117b, the hydrogen introduction hole of the negative electrode insulating plate 113, and the hydrogen introduction hole of the negative electrode panel plate 111. A plurality of negative electrode openings 121 reaching 100 negative electrode diffusion layers 105 are formed, and hydrogen in the fuel tank portion 119 is supplied from the negative electrode openings 121 to the negative electrode diffusion layer 105.

  In the fuel cell 1, a positive electrode panel plate 110, a negative electrode panel plate 111, and a fuel tank portion 119 are integrally fixed by bolts 122 and nuts 123. In addition, 118a and 118b in FIG. 10 are seals.

  The positive electrode diffusion layer 101 and the negative electrode diffusion layer 105 are made of a porous electron conductive material or the like, for example, a porous carbon sheet subjected to a water repellent treatment. A carbon powder containing fluororesin particles (such as PTFE resin particles) is formed on the catalyst layer side of the positive electrode diffusion layer 101 or the negative electrode diffusion layer 105 for the purpose of further improving water repellency and improving the contact property with the catalyst layer. In some cases, the paste is applied.

  The positive electrode catalyst layer 102 has a function of reducing oxygen diffused through the positive electrode diffusion layer 101, and includes, for example, a carbon powder carrying a catalyst (catalyst-carrying carbon powder) and a proton conductive material. is doing. Moreover, you may further contain the resin binder as needed.

  The catalyst contained in the positive electrode catalyst layer 102 is not particularly limited as long as it can reduce oxygen. For example, platinum fine particles can be used. The catalyst may be fine particles composed of an alloy of platinum and at least one metal element selected from the group consisting of iron, nickel, cobalt, tin, ruthenium and gold.

As the carbon powder as the catalyst carrier, for example, carbon black having a BET specific surface area of 10 to 2000 m ² / g and an average particle diameter of 20 to 100 nm is used. The catalyst can be supported on the carbon powder by, for example, a colloid method.

  As a content ratio of carbon powder and a catalyst, it is preferable that a catalyst is 5-400 mass parts with respect to 100 mass parts of carbon powder, for example. With such a content ratio, the positive electrode catalyst layer 102 having sufficient catalytic activity can be configured. Further, for example, when the catalyst-supported carbon powder is produced by a method of depositing the catalyst on the carbon powder (for example, a colloid method), the catalyst diameter is as long as the carbon powder and the catalyst have the above-mentioned content ratio. Sufficient catalytic activity can be obtained without becoming too large.

  The proton conductive material contained in the positive electrode catalyst layer 102 is not particularly limited. For example, a resin having a sulfonic acid group such as a polyperfluorosulfonic acid resin, a sulfonated polyether sulfonic acid resin, or a sulfonated polyimide resin is used. Can be used. Specific examples of the polyperfluorosulfonic acid resin include “Nafion (registered trademark)” manufactured by DuPont, “Flemion (registered trademark)” manufactured by Asahi Glass, and “Aciplex (trade name) manufactured by Asahi Kasei Kogyo Co., Ltd. Or the like.

  And it is preferable that content of the proton conductive material in the positive electrode catalyst layer 102 is 2-200 mass parts with respect to 100 mass parts of catalyst carrying | support carbon powder. If the proton conductive material is contained in the above-mentioned amount, sufficient proton conductivity is obtained in the positive electrode catalyst layer, and the electric resistance value does not become too large, and a fuel cell with good battery performance can be obtained.

  The binder used for the positive electrode catalyst layer 102 is not particularly limited, and examples thereof include PTFE, PFA, FEP, tetrafluoroethylene-ethylene copolymer (E / TFE), polyvinylidene fluoride (PVDF), and poly Fluoropolymers such as chlorotrifluoroethylene (PCTFE), polyethylene, polypropylene, nylon, polystyrene, polyester, ionomer, butyl rubber, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, and ethylene / acrylic acid copolymer Non-fluororesin such as can be used.

  The binder content in the positive electrode catalyst layer 102 is preferably 0.01 to 100 parts by mass with respect to 100 parts by mass of the catalyst-supporting carbon powder. If the binder is contained in the above-described amount, sufficient binding properties can be obtained for the positive electrode catalyst layer, and the electric resistance value does not become too large, and a fuel cell with good battery performance can be obtained.

  The negative electrode catalyst layer 104 has a function of oxidizing hydrogen diffused through the negative electrode diffusion layer 105. The negative electrode catalyst layer 104 contains, for example, carbon powder carrying a catalyst (catalyst carrying carbon powder) and a proton conductive material. If necessary, a binder such as a resin may be further contained.

  The catalyst used for the negative electrode catalyst layer 104 is not particularly limited as long as it can oxidize hydrogen. For example, the above-described catalysts exemplified as the catalyst used for the positive electrode catalyst layer 102 can be used. Regarding the carbon powder, proton conductive material, and binder used for the negative electrode catalyst layer 104, the above-described materials exemplified as the carbon powder, proton conductive material, and binder used for the positive electrode catalyst layer 102 can be used.

  The solid electrolyte membrane 103 is not particularly limited as long as it is a membrane made of a material that can transport protons and does not exhibit electronic conductivity. As a material that can constitute the solid electrolyte membrane 103, for example, polyperfluorosulfonic acid resin, specifically, "Nafion (registered trademark)" manufactured by DuPont, "Flemion (registered trademark)" manufactured by Asahi Glass, Examples include “Aciplex (trade name)” manufactured by Asahi Kasei Corporation. In addition, sulfonated polyether sulfonic acid resin, sulfonated polyimide resin, sulfuric acid-doped polybenzimidazole, and the like can also be used as the material of the solid electrolyte membrane 103.

  FIG. 11 shows a specific configuration example of a hydrogen supply apparatus applicable to the fuel cell power generation system of the present invention. FIG. 11 is a block diagram of a hydrogen supply device, in which water is supplied to a hydrogen generating material continuously or intermittently, and hydrogen is generated by reacting the hydrogen generating material with water to generate hydrogen. The device is shown.

  The hydrogen supply device 2 shown in FIG. 11 includes a hydrogen generating substance storage container 301 that stores a hydrogen generating substance 302 and a water storage container 303 that stores water 304. Water 304 is supplied from the container 303, and the hydrogen generating substance 302 and the water 304 are reacted to generate hydrogen. For this reason, the hydrogen generating substance storage container 301 also serves as a hydrogen generating container that is a reaction container for the hydrogen generating substance 302 and the water 304. Hydrogen generated in the hydrogen generating substance storage container 301 is supplied to the hydrogen removing device 3 through the hydrogen outlet pipes 305 and 306, and further supplied to the fuel cell 1 through the hydrogen flow path 7. Note that the hydrogen outlet pipe 306 is provided with a stop valve 5.

  A water supply pump 308 is provided in a water supply pipe 307 that supplies water 304 from the water storage container 303 to the hydrogen generating substance storage container 301. The water 304 stored in the water storage container 303 may be neutral water, an acidic aqueous solution, an alkaline aqueous solution, or the like, and a suitable one according to the reactivity with the hydrogen generating substance 302 to be used. Just choose.

  The hydrogen generating substance storage container 301 and the water storage container 303 may be detachable. As a result, when the hydrogen generating substance 302 in the hydrogen generating substance storage container 301 is completely consumed or when the water 304 in the water storage container 303 is exhausted, these are removed and the hydrogen generating substance filled with the hydrogen generating substance 302 is generated. By newly attaching the substance container 301 or the water container 303 filled with water 304, hydrogen production can be performed again.

  The hydrogen generating substance 302 stored in the hydrogen generating substance storage container 301 is not particularly limited as long as it can generate hydrogen by reacting with water 304 at a low temperature of 120 ° C. or lower. For example, metals such as aluminum, silicon, zinc, and magnesium, alloys mainly composed of one or more elements of aluminum, silicon, zinc, and magnesium, and metal hydrides can be preferably used.

  Here, in the case of using an alloy mainly composed of one or more elements of aluminum, silicon, zinc and magnesium, elements other than each element of the main alloy are not particularly limited. Here, the “main body” means that 80% by mass or more, more preferably 90% by mass or more is contained with respect to the entire alloy. These metals such as aluminum, silicon, zinc, and magnesium, and alloys mainly composed of one or more elements of aluminum, silicon, zinc, and magnesium are difficult to react with water at room temperature. It is a substance that facilitates exothermic reaction with water. In addition, normal temperature shall show the temperature of the range of 20-30 degreeC.

Here, the reaction between the hydrogen generating substance and water will be described in detail. For example, in the case of aluminum and water, the reaction for producing hydrogen and oxidation products is as follows:
2Al + 6H ₂ O → Al ₂ O ₃ .3H ₂ O + 3H ₂ (1)
2Al + 4H ₂ O → Al ₂ O ₃ .H ₂ O + 3H ₂ (2)
2Al + 3H ₂ O → Al ₂ O ₃ + 3H ₂ (3)

  The hydrogen generating material made of the metal or alloy is stabilized by forming an oxide film on the surface. For this reason, it is preferable to make the particle size of the hydrogen generating material as small as possible and increase the reaction area. For example, the form of the hydrogen generating substance is preferably in the form of particles or flakes having a particle diameter of 0.1 to 100 μm, and the particle diameter is more preferably 0.1 to 50 μm. This is because hydrogen generation occurs smoothly when the particle size of the hydrogen generating substance is 100 μm or less. Further, when the particle size of the hydrogen generating material is reduced, the hydrogen generation rate is increased. However, when the particle size is smaller than 0.1 μm, the flammability is increased and handling becomes difficult. Moreover, since the bulk density is reduced, the filling density of the hydrogen generating material is lowered, and the energy density is likely to be lowered. For this reason, it is preferable that the particle size of the hydrogen generating substance is 0.1 μm or more.

  Here, the particle diameter of the hydrogen generating material is an average particle diameter, and means a value of the particle diameter at a volume-based integrated fraction of 50%. As a method for measuring the average particle diameter, for example, a laser diffraction / scattering method or the like can be used. Specifically, this is a particle diameter distribution measurement method using a scattering intensity distribution detected by irradiating a measurement target substance dispersed in a liquid phase such as water with laser light. As a particle size distribution measuring apparatus using a laser diffraction / scattering method, for example, “Microtrac HRA (product name)” manufactured by Nikkiso Co., Ltd. can be used.

  Examples of the metal hydride that can be used as the hydrogen generating substance include sodium borohydride and potassium borohydride. These metal hydrides are relatively stable in an aqueous alkali solution, but when a catalyst is present, they can rapidly react with water to generate hydrogen. As the catalyst, for example, metals such as Pt and Ni, acids, and the like can be used.

For example, in the case of sodium borohydride, it can react as the following formula to generate hydrogen.
NaBH ₄ + 2H ₂ O → NaBO ₂ + 4H ₂ (4)

  As the hydrogen generating substance, those exemplified above may be used alone or in combination of two or more.

  Further, by using the hydrogen generating material together with a heat generating material (a material other than the hydrogen generating material) that generates heat by reacting with water, even if low temperature (for example, about 5 ° C.) water is supplied, The temperature in the reaction system can be increased by exotherm, and rapid hydrogen generation can be enabled.

  The exothermic substance that generates heat by reacting with water is, for example, calcium oxide, magnesium oxide, calcium chloride, magnesium chloride, calcium sulfate, etc. Examples include exothermic alkali metal or alkaline earth metal oxides, chlorides, and sulfuric acid compounds. In addition, those that generate hydrogen by reaction with water, such as metal hydrides such as sodium borohydride, potassium borohydride, and lithium hydride, can be used as a hydrogen generating substance as described above. However, it can also be used as a heat generating material when the metal or alloy is used as a hydrogen generating material.

  For example, a heat-generating substance that reacts with oxygen and generates heat, such as iron powder, is also known. However, when iron powder is used as the exothermic substance, oxygen must be introduced during the reaction, and it occurs when the hydrogen generating substance and the exothermic substance are arranged in the same reaction vessel as described above. Problems such as reduction in the purity of hydrogen and reduction in the amount of hydrogen generated due to oxidation of the hydrogen generating substance by oxygen are likely to occur. Therefore, as the exothermic substance, a material that generates heat by reacting with water is preferably used.

  In particular, when a metal such as aluminum, silicon, zinc, and magnesium or an alloy mainly composed of one or more elements selected from aluminum, silicon, zinc, and magnesium is used as the hydrogen generating material, the heat generating material is used. It is preferable to use together. On the other hand, when the metal hydride is used as a hydrogen generating substance, hydrogen can be produced at a relatively good rate without using the exothermic substance. May be increased.

  When the hydrogen generating substance 302 and the exothermic substance are used in combination, the amount of the hydrogen generating substance 302 is 85% by mass or more in a total of 100 mass% of the hydrogen generating substance 302 and the exothermic substance introduced into the hydrogen generating substance storage container 301. It is preferable to do. If the amount of the hydrogen generating substance 302 in the total of the hydrogen generating substance 302 and the exothermic substance is too small, the amount of hydrogen generating decreases, or if the amount of the exothermic substance is too large, the heat generation becomes intense and it becomes difficult to control the hydrogen generating reaction. There is a risk of doing.

  The exothermic material may be mixed into the hydrogen generating material storage container 301 as a mixture that is uniformly or non-uniformly mixed with the hydrogen generating material 302, or may be stored in the hydrogen generating material storage container 301 separately from the hydrogen generating material 302. Good. In the latter case, for example, it is preferable to dispose the exothermic material in the vicinity of the mouth portion of the water supply pipe 307 that supplies the water 304 to the hydrogen generating material storage container 301. By arranging the exothermic material in this way, the inside of the reaction system can be heated more efficiently.

  The material and shape of the hydrogen generating substance storage container 301 are not particularly limited as long as the hydrogen generating substance 302 that generates hydrogen can be stored. However, the water 304 and hydrogen are not supplied from the water 304 supply port or the hydrogen outlet. Materials and shapes that do not leak are preferred. As a specific material of the container, a material that does not easily transmit water 304 and hydrogen and that does not break even when heated to about 120 ° C. is preferable. For example, a metal such as aluminum or iron, or a resin such as polyethylene or polypropylene Can be used. Further, as the shape of the container, a prismatic shape, a cylindrical shape or the like can be adopted.

  There is no restriction | limiting in particular about the water storage container 303, For example, the tank etc. which store the water 304 conventionally used for the hydrogen supply apparatus are employable.

  The water 304 in the water storage container 303 is supplied to the hydrogen generating substance storage container 301 through the water supply pipe 307, thereby reacting with the hydrogen generating substance 302 in the hydrogen generating substance storage container 301 to generate hydrogen. In some cases, unreacted water present in the hydrogen generating substance storage container 301 is mixed in the generated hydrogen, and the mixture thereof is discharged out of the hydrogen supply device 2 through the hydrogen outlet pipe 305.

  Therefore, as shown in FIG. 11, the hydrogen supply device 2 is preferably provided with a condensed water separator 309 before the hydrogen outlet pipe 306 that supplies hydrogen to the fuel cell 1 and the hydrogen removal device 3. The condensed water separator 309 is connected to the hydrogen generating substance storage container 301 via a hydrogen outlet pipe 305, and a hydrogen outlet pipe 306 is attached. The water in the mixture with hydrogen discharged from the hydrogen generating substance storage container 301 is cooled in the hydrogen outlet pipe 305 to become condensed water. When hydrogen accompanied with the condensed water is introduced into the condensed water separator 309, the condensed water falls to the lower part of the condensed water separator 309 and is separated by gravity.

  Then, as shown in FIG. 11, the water separated by the condensed water separator 309 is recovered in the water storage container 303 by connecting the condensed water separator 309 and the water storage container 303 by the water recovery pipe 310. be able to. Thus, by collecting the water separated by the condensate separator 309, it is possible to reduce the substantial supply amount of water used for hydrogen generation, and to make the water storage container 303 more compact. be able to.

  Although the flocculated water separator has been described as a part of the hydrogen supply device in FIG. 11, the flocculated water separator may be used outside the hydrogen supply device, and the flocculated water separator itself is not essential. Therefore, it may be determined as appropriate depending on the situation.

  FIG. 12 shows a specific configuration example of the hydrogen removing device 3 which is a hydrogen removing unit suitable for the fuel cell power generation system of the present invention. FIG. 12 is a schematic cross-sectional view of a main part of the hydrogen removal device 3. However, in FIG. 12, in order to facilitate understanding of each component, a part of the component is not hatched indicating that it is a cross section.

  The hydrogen removal apparatus shown in FIG. 12 is configured by a cell 400 having the same structure as the unit cell 100 of the fuel cell 1 in which the positive electrode and the negative electrode can be conducted. That is, the cell 400 includes a positive electrode catalyst layer 402 that reduces oxygen and a negative electrode catalyst layer 404 that oxidizes hydrogen, and further includes a solid electrolyte membrane 403 between the positive electrode catalyst layer 402 and the negative electrode catalyst layer 404. ing. Further, the positive electrode diffusion layer 401 is laminated on the surface of the positive electrode catalyst layer 402 opposite to the solid electrolyte membrane 403 side, and the surface of the negative electrode catalyst layer 404 opposite to the solid electrolyte membrane 403 side is stacked. A negative electrode diffusion layer 405 is stacked. These can be made of the same material as that of the unit cell 100 according to the fuel cell 1 described in FIG.

  The cell 400 is sandwiched between a positive electrode current collector plate 406 disposed above the positive electrode diffusion layer 401 and a negative electrode current collector plate 407 disposed below the negative electrode diffusion layer 405. The current collector plate 407 and the fuel tank 411 to which hydrogen is supplied are fixed by, for example, bolts 408 and nuts 409. Reference numeral 410 denotes a sealing material made of silicon rubber or the like.

  The hydrogen removal device 3 shown in FIG. 12 is connected to the hydrogen supply device 2 via the hydrogen outlet pipe 306 and is connected to the fuel cell 1 via the hydrogen flow path 7. Note that the hydrogen outlet pipe 306 is provided with a stop valve 5.

  The positive electrode current collector plate 406 and the negative electrode current collector plate 407 are made of, for example, a noble metal such as platinum or gold, a corrosion-resistant metal such as stainless steel, or carbon. In addition, the surface may be plated or painted to improve the corrosion resistance.

  A plurality of air holes 412 are formed in the positive electrode current collector plate 406, and oxygen in the atmosphere is supplied to the positive electrode of the cell 400 through these air holes 412. On the other hand, a plurality of hydrogen introduction holes 413 are formed in the negative electrode current collector plate 407, and hydrogen introduced from the hydrogen outlet pipe 306 to the fuel tank portion 411 through these hydrogen introduction holes 413 is supplied to the negative electrode of the cell 400. .

  A positive electrode lead wire 414 is connected to the end portion of the positive electrode current collector plate 406, and a negative electrode lead wire 415 is connected to the end portion of the negative electrode current collector plate 407. These lead wires 414 and 415 are connected via a resistor 416 and a switch 417. When the hydrogen removal apparatus 3 is operated, the switch 417 is turned on to conduct between the positive electrode and the negative electrode of the cell 400 manually or by a control signal from a control means (for example, 10 in FIG. 6). Thus, the hydrogen supplied from the hydrogen supply device 2 into the hydrogen removal device 3 can be consumed. Thereby, surplus hydrogen which goes to the fuel cell 1 through the hydrogen flow path 7 from the hydrogen removal apparatus 3 can be removed.

  In the hydrogen removal device 3 shown in FIG. 12, the example in which the positive electrode and the negative electrode of the cell 400 are connected via the resistor 416 is shown. However, the resistor 416 may be the cell 400 after the operation of the hydrogen removal device 3 is started. A resistor having such a resistance value that the time required for the voltage between the positive electrode and the negative electrode to be 0.1 V or less may be used within one minute. In addition, the resistor 416 is not indispensable. If the voltage between the positive electrode and the negative electrode of the cell 400 can be reduced to 0.1 V or less in the same time without using a resistor, the positive electrode and the negative electrode of the cell 400 are used. May be made conductive by connecting with a lead body or the like only through a switch without using a resistor.

  Next, an example of a control mode of the openable / closable door provided at the positive electrode opening in the fuel cell power generation system of the present invention will be described with reference to FIG. FIG. 13 is a flowchart showing the control procedure of the door in the fuel cell power generation system. Based on FIG. 13, the situation at the time of power generation and stop after the fuel cell power generation system is started will be described.

  In this case, a hydrogen supply device having a structure for supplying water from a water storage container using a water supply pump is used in a hydrogen generation material storage container containing a hydrogen generation material as shown in FIG. A case of a fuel cell power generation system using a temperature sensor capable of detecting the surface temperature of each cell as detection means (6 in FIG. 6) will be described.

  As shown in the flowchart of FIG. 13, when the fuel cell power generation system is activated, the water supply pump of the hydrogen supply device is turned on in step S1, and water is supplied to the hydrogen generating substance storage container to start generation of hydrogen. At the same time, a temperature sensor, which is a detection means for grasping the surface temperature of each cell of the fuel cell, is also turned on.

  In the next step S2, when hydrogen is supplied from the hydrogen supply device 2 to the fuel cell 1, the switch (SW, 11 in FIG. 6) is turned on to supply the output to the external load 4.

  Subsequent step S3 differs depending on the size of the fuel cell power generation system. For example, a case where the temperature level of the detection means is set to three levels of α ° C., β ° C. and γ ° C. will be described. When the surface temperature (t) of the cell is higher than α ° C. (eg,> 55 ° C.), the opening degree of the positive electrode opening is lowered by the open / close door to prevent the solid electrolyte membrane from drying. On the other hand, when β ° C. <t <α ° C. (for example, 30 ° C. <t <55 ° C.), the opening / closing door opens the positive electrode opening so that a large amount of air (oxygen) can be taken in from the positive electrode opening. Increase the degree. When γ ° C. <t <β ° C. (for example, 15 ° C. <t <30 ° C.), in a dry environment where the outside air temperature is low, the opening of the positive electrode opening is opened by an open / close door to prevent the solid electrolyte membrane from drying. Reduce the degree.

  In the next step S4, the external load is turned off and the switch is turned off. At this time, the fuel cell power generation system has a hydrogen removal device (for example, the hydrogen removal device shown in FIG. 12), or is configured so that the positive and negative electrodes of each cell of the fuel cell according to the fuel cell power generation system can communicate with each other. If it has been performed (FIG. 7), in step S5 at the same time as step S4, the positive and negative electrodes of the cell of the hydrogen removal device and each unit cell of the fuel cell are made conductive, and the fuel cell and the fuel cell and the hydrogen supply device Excess hydrogen in the hydrogen flow path is consumed.

  Thereafter, in step S6, the open / close door is closed so that the degree of opening of the positive electrode opening is about 0% in order to prevent the solid electrolyte membrane of each cell in the fuel cell from being dried during the rest.

  Note that, depending on the size of the system, the detection means for controlling the degree of opening of the positive electrode opening includes, for example, a humidity sensor in addition to the temperature sensor described above. It is also possible to use a plurality of temperature sensors and humidity sensors. When a plurality of sensors are installed, it becomes possible to know the dry state of the solid electrolyte membrane more accurately.

  In addition, when a temperature sensor that monitors the surface temperature of the cell is used as the detection means, its mounting position is not particularly limited as long as it can accurately detect a temperature change. For example, in the vicinity of the positive electrode opening of each unit cell It is desirable to install it on the seal or directly on the seal part. In particular, as the temperature sensor, for example, a thermistor or a thermocouple is preferably used as a small sensor having good sensitivity.

  Although specific embodiments of the fuel cell power generation system of the present invention have been described above, the present invention is not limited to these specific examples. For example, the structure of the unit cell of the fuel cell shown in FIG. 10 is merely an example, and various specific forms known as a polymer electrolyte membrane fuel cell can be adopted.

  As for the hydrogen supply device, the specific example of the hydrogen generating material and the mechanism for reacting water and the hydrogen generating material are merely examples. Furthermore, the hydrogen supply means itself is not limited to the method of reacting the hydrogen generating substance with water, and other hydrogen supply methods can be applied to the present invention. In particular, when the supply amount of hydrogen is likely to change with time, such as a method for extracting hydrogen from a hydrogen storage alloy, the above-described hydrogen removal apparatus and each cell of the fuel cell are included in the fuel cell power generation system of the present invention. By providing a configuration capable of removing surplus hydrogen, it is possible to effectively remove surplus hydrogen in the system.

  Further, the hydrogen removal apparatus is not limited to the structure shown in FIG. 12, and other methods capable of removing a predetermined amount of hydrogen from the hydrogen flow path can also be used.

  Further, the case where a temperature sensor that detects the surface temperature of each unit cell is used as a detection means for obtaining information that is the basis for controlling the opening degree of the positive electrode opening of the fuel cell has been described. However, the present invention is not limited to this, and a humidity sensor as described above and a method for detecting the amount of water are also conceivable. That is, any means can be used as long as it can detect or predict the water content of the solid electrolyte membrane in each unit cell that changes with the passage of time from the start of the operation of the hydrogen supply device.

  Further, in the configuration example of the fuel cell power generation system of the present invention of FIGS. 6 to 9, the form in which the fuel cell 1 and the external load 4 are connected / disconnected by the switch 11 is shown, but this switch 11 is merely conceptual. Therefore, a switch as a circuit element does not necessarily exist. By connecting and disconnecting the external load itself, it may be possible to switch on / off the power supply to the external load, or it may be assumed that the external load is always connected to the fuel cell in the circuit configuration.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

Reference example [Fabrication of fuel cell]
A fuel cell having the configuration shown in FIG. 14 was produced. As the positive electrode and the negative electrode of the unit cell 100, an electrode (“LT140E-W” manufactured by E-TEK, Pt amount: 0.5 mg / cm ² ) coated with Pt-supported carbon on a carbon cloth was used. Further, “Nafion 112” manufactured by DuPont was used for the solid electrolyte membrane. Each electrode was 25 mm × 92 mm, and the solid electrolyte membrane was 29 mm × 96 mm. Then, the three unit cells 100, 100, 100 were connected in series and integrated to constitute the fuel cell 1.

  Hereinafter, the details of the fuel cell 1 will be described with reference to FIG. The positive electrode panel plate 110 made of SUS304 and having a thickness of 2 mm was used. A total of 72 oxygen introduction holes for forming the positive electrode opening 201 were arranged over the entire region corresponding to the upper part of the positive electrode diffusion layer 101 of each unit cell 100 as rectangular holes of 1 × 13 mm. The negative electrode panel plate 111 also has the same material and shape as the positive electrode panel plate 110. That is, in the negative electrode panel plate, the oxygen introduction hole related to the positive electrode panel plate is a hydrogen introduction hole for forming the negative electrode opening (121 in FIG. 10).

  As the positive electrode current collecting plates 114, 116a, and 116b, those having a thickness of 0.3 mm in which nickel was plated with gold were used. The shape and arrangement of the oxygen introduction holes are the same as those of the positive electrode panel plate 110. The negative electrode current collecting plates 115, 117a, 117b were also made of the same material and shape as the positive electrode current collecting plates 114, 116a, 116b.

  A positive electrode insulating plate 112 made of glass epoxy resin and having a thickness of 0.5 mm was used. The shape and arrangement of the oxygen introduction holes are the same as those of the positive electrode panel plate 110. The negative electrode insulating plate 113 is also made of the same material and shape as the positive electrode insulating plate 112.

  The fuel tank portion 119 is made of glass epoxy resin and has a thickness of 3 mm. The depth inside the central tank is 2 mm. The seals 118a and 118b are made of silicon and have a thickness of 0.2 mm. The size of the hole formed in the portion where the electrode is accommodated was set to 26 m × 93 mm.

  The above members were stacked as shown in FIG. 10 and tightened with bolts and nuts to assemble a fuel cell. As shown in FIG. 10, an opening / closing door 200 slidable in the right and left directions in the figure is sandwiched between the positive electrode panel plate 110 and the positive electrode insulating plate 112. By sliding the open / close door 200, the opening degree when the area of the unit cell in plan view is set as a reference (opening degree 100%) can be adjusted to 20%, 30%, and 40%.

  A fuel cell power generation system having the configuration shown in FIG. 14 is configured using each of the fuel cells described above, and hydrogen gas having a purity of 99.9% supplied from a hydrogen cylinder serving as the hydrogen supply source 2a is placed in water at about 25 ° C. The fuel cell power generation system was supplied with the fuel cell power generation system, and a fuel cell power generation test was performed.

  In the above power generation test, the external load 4 is changed every hour, and at the same time, the flow rate of hydrogen is changed so that the utilization rate of supplied hydrogen becomes 90% or more. Was increased from 1.8 V to 2.4 V by 0.15 V every hour, and the value when the current value stabilized at each voltage was recorded.

  Further, in order to measure the surface temperature of the unit cell of the fuel cell, a thermocouple (K type) was attached in the vicinity of the positive electrode opening, and the surface temperature of the unit cell at the time of measuring the current value was recorded. The ambient environment at the time of measurement was a temperature of 20 ° C. to 24 ° C. and a relative humidity of 22% RH to 31% RH.

  FIG. 15 shows the change in the output of the fuel cell when the power generation test is performed with the opening degree of the positive electrode opening fixed at 20%, 30% and 40%. In the graph of FIG. 15, each output of the fuel cell is shown as a relative value with the output of the power generation test result at 1.8 V when the opening degree of the positive electrode opening is adjusted to 30%.

  From the results shown in FIG. 15, when the voltage is 2.4 V and the output is low, that is, when the hydrogen flow rate is small, it is confirmed that the output tends to decrease as the opening degree increases. This is presumably because, when the output is low, the amount of generated water is small and the surrounding environment is in a dry state, and if the opening degree is high, the solid electrolyte membrane is dried and the output is reduced.

  On the other hand, at a high output of 1.95 V, that is, when the hydrogen flow rate is large, the output is the highest when the opening degree is adjusted to 40% at which a large amount of oxygen can be taken. However, when the hydrogen flow rate is 1.80 V, which has a higher hydrogen flow rate, the output tends to decrease when the opening degree is rather low. At this time, the surface temperature of the unit cell is over 56 ° C., and the solid electrolyte membrane is likely to dry due to the heat generated by the fuel cell itself. It is considered that lowering the degree of opening to prevent the solid electrolyte membrane from drying will lead to improved output. Therefore, by adjusting the degree of opening of the positive electrode opening according to the output of the fuel cell, it is possible to prevent a decrease in output due to drying of the solid electrolyte membrane.

  Based on the above results, the power amount of the fuel cell when the power generation test was performed by changing the opening degree of the positive electrode opening portion between 20 to 40% according to the output of the fuel cell, the opening degree was set to 20 It is shown in Table 1 together with the amount of electric power when power is generated at a fixed rate of 30% and 40%.

  As is clear from Table 1, the output of the fuel cell can be prevented from decreasing by adjusting the opening degree of the positive electrode opening according to the output of the fuel cell. Therefore, the above-described effect can be obtained by incorporating the apparatus of this reference example into a fuel cell power generation system of an embodiment described later.

Example 1
A fuel cell power generation system having the configuration shown in FIG. 16 was produced.

[Fabrication of fuel cell]
6 unit cells 100 in which the positive electrode and the negative electrode can be conducted through the resistor 12 are connected in series, and the opening degree of the positive electrode opening by the open / close door 200 is 30% in accordance with the result of the preliminary test. Produced a fuel cell in the same manner as the preliminary test.

[Production of hydrogen removal equipment]
A hydrogen removal apparatus having the configuration shown in FIG. 12 was produced. The constituent members of the cell 400 are the same as those of the unit cell 100 of the fuel cell. The electrode was 6 mm square, and the solid electrolyte membrane was 8 mm square. As the positive electrode current collector plate 406, a SUS304 gold-plated plate having a thickness of 2 mm was used. As the air holes 412, 1 × 60 mm rectangular holes were arranged over the entire portion corresponding to the upper part of the positive electrode diffusion layer 401 of the cell 400 as shown in FIG. 12. The negative electrode current collector plate 407 also has the same shape and material as the positive electrode current collector plate 406.

  The fuel tank portion 411 is made of glass epoxy resin and has a thickness of 3 mm. The depth inside the central tank is 2 mm. The seal material 410 was made of silicon rubber and had a thickness of 0.2 mm. The size of the hole formed in the portion where the electrode is accommodated was 61 mm square.

  The above members were laminated as shown in FIG. 12, and tightened with bolts and nuts. Further, a positive electrode lead wire 414 is arranged at an end portion of the positive electrode current collector plate 406, and a negative electrode lead wire 415 is arranged at an end portion of the negative electrode current collector plate 407, and a switch 417 and a resistor 416 of 20 mΩ are connected therebetween. A hydrogen removal device was obtained.

[Production of hydrogen supply device]
A hydrogen supply apparatus having the configuration shown in FIG. 11 was produced. As the hydrogen generating substance storage container 301, a polypropylene prismatic container having an internal volume of 50 cm ³ was used. Polypropylene pipes having an inner diameter of 2 mm and an outer diameter of 3 mm were used for the water supply pipe 307, the hydrogen outlet pipes 305 and 306, and the water recovery pipe 310. In a hydrogen generating substance storage container 301, 12.3 g of aluminum powder having an average particle diameter of 3 μm as hydrogen generating substance and 1.6 g of calcium oxide as exothermic substance were put. A polypropylene prismatic container having an internal volume of 50 cm ³ was used as the water container 303, and 30 g of water was placed therein. As the condensate separator 309, a polypropylene prismatic container having an internal volume of 30 cm ³ was used.

[Assembly of fuel cell power generation system]
A fuel cell power generation system having the configuration shown in FIG. 16 was assembled using the fuel cell 1, the hydrogen supply source 2, and the hydrogen removal device 3. A check valve was used for the backflow prevention means 9a, 9b. Further, the air flow path 13 is formed by joining the opposite sides of the backflow prevention means 9a and 9b to the fuel cell 1 side, and the mass flow meter 14 is connected to the air flow path 13 so that in the fuel cell 1 of the fuel cell power generation system, It was made possible to monitor the flow rate of the gas entering and exiting through the ventilation paths 8 and 13 and the backflow prevention means 9a and 9b. As the mass flow meter 14, “Mass Flow 8100” manufactured by KOFLOC was used.

<Power generation test>
The water supply pump 308 supplies the water in the water storage container 303 to the hydrogen generating substance storage container 301 to generate hydrogen, and the external load 4 performs a power generation test of the fuel cell 1 at a constant voltage of 4.0 V for 1 hour. It was. In addition, 40 minutes after the start of the power generation test, monitoring of the voltage value (A) of the unit cell 100 on the hydrogen supply device 2 side of the fuel cell 1 and the voltage value (B) of the unit cell 100 on the ventilation path 8 side is started. The monitoring of the voltage values (A) and (B) was continued for 200 seconds. Moreover, the excess gas discharged | emitted from the ventilation path 8 was measured with the mass flow meter 14 which is a monitoring apparatus.

  After supplying power to the external load 4 for one hour, the external load 4 is turned off and the water supply by the water supply pump 308 is stopped. At the same time, the switch 417 of the hydrogen removal device 3 and each unit cell 100 of the fuel cell 1 are stopped. The switch provided on the lead body connecting between the positive electrode and the negative electrode was turned on.

Comparative Example 1
Using the fuel cell power generation system having the same configuration as that of the first embodiment, the water supply pump 308 of the hydrogen supply device 2 supplies water in the water storage container 303 to the hydrogen generating substance storage container 301 to generate hydrogen, and the external load 4 The fuel cell power generation test was started at a constant voltage of 4.0V. The test was performed at room temperature of 25 ° C.

  After 40 minutes from the start of the power generation test, the backflow prevention means 9a and 9b are removed from the fuel cell power generation system, and after the voltage of the fuel cell 1 has stabilized, the voltage values (A) and (B) are monitored for 200 seconds. It was.

Comparative Example 2
Example 1 except that the hydrogen removing device 3 was not used, and the fuel cell 1 was not provided with the lead body and the resistor 11 that connected between the positive electrode and the negative electrode of each unit cell 100 and the backflow prevention devices 9a and 9b. A fuel cell power generation system was prepared in the same manner as described above, and a power generation test was performed in the same manner as in Example 1.

  FIG. 17 shows the voltage value (A) of the unit cell 100 on the hydrogen supply device 2 side of the fuel cell 1 and the voltage value (B) of the unit cell 100 on the ventilation path 8 side in the power generation test of Example 1 and Comparative Example 1. Shows changes. In FIG. 17, the vertical axis indicates the voltage values (A) and (B) as relative values [voltage relative value (A) and voltage relative value (B)]. The voltage relative value (A) in FIG. 5 is based on the voltage value (A) at the start of monitoring in Example 1, and the voltage relative value (B) in Example 1 and Comparative Example 1 is the monitoring in Example 1. The voltage value (B) at the start is used as a reference. In addition, the horizontal axis of FIG. 17 indicates the time from the start of monitoring the voltage values (A) and (B).

  From the results shown in FIG. 17, when the voltage relative value (B) of Example 1 and Comparative Example 1 are compared, the voltage relative value (B) of Comparative Example 1 is decreased. This is because the backflow prevention devices 9a and 9b are not installed in the fuel cell power generation system of Comparative Example 1 [the backflow prevention devices 9a and 9b are removed before monitoring the voltage values (A) and (B)]. From this, it is considered that outside air is mixed due to fluctuations in the pressure of hydrogen supplied into the fuel cell 1, and the voltage of the unit cell on the ventilation path 8 side, which is easily affected by outside air, is thus lowered. On the other hand, in the fuel cell power generation system of the first embodiment in which the backflow prevention devices 9a and 9b are installed, it is possible to suppress pressure fluctuations during operation of the fuel cell 1 and to prevent outside air from being mixed. Thus, the voltage of the unit cell in the fuel cell is stable regardless of the arrangement.

  From the above, it can be seen that a fuel cell power generation system with higher output stability can be obtained by setting the positive electrode opening to an opening degree adapted to the surrounding environment and including the backflow prevention means.

  In the power generation test by the fuel cell power generation system of Example 1 and Comparative Example 2, the voltage change after the operation of the fuel cell 1 is stopped (after the external load 4 is turned off and the water supply by the water supply pump 308 is stopped). Was measured, and the time taken for the voltage of the fuel cell 1 to drop to 0.2 V was determined. The results are shown in Table 2.

  Even after the water supply pump 308 was stopped, the hydrogen supply from the hydrogen supply device 2 to the fuel cell 1 side continued for a while. Therefore, as shown in Table 2, the hydrogen removal device 3 was not provided and the remaining in the fuel cell 1 remained. In the fuel cell power generation system of Comparative Example 2 having no means for consuming hydrogen, a considerable time was required for the voltage drop. However, in the fuel cell power generation system of Example 1 having the hydrogen removal device 3, the hydrogen removal device 3 The amount of hydrogen flowing into the fuel cell 1 can be greatly reduced, and the residual hydrogen can be consumed by the resistance 11 of each unit cell 100 in the fuel cell 1, so that the voltage can be quickly reduced. From these results, in the fuel cell power generation system of Example 1 having the hydrogen removal device 3, it can be expected that the life of the unit cell in the fuel cell 1 is extended.

  In the fuel cell power generation system of the present invention, the output can be stabilized with a relatively simple configuration, and preferably the life of the fuel cell can be extended, so that the system can be easily downsized. . Therefore, the fuel cell power generation system of the present invention can be suitably used for various applications to which conventional fuel cells are applied, including power supply applications for high-performance portable electronic devices.

It is a perspective view showing typically an example of a fuel cell concerning a fuel cell power generation system of the present invention. It is a schematic diagram for demonstrating an example of the mechanism of a sliding-type door which can be opened and closed. It is a schematic diagram for demonstrating the other example of the mechanism of the sliding-type door which can be opened and closed. It is a perspective view which shows typically the other example of the fuel cell which concerns on the fuel cell power generation system of this invention. It is a schematic diagram for demonstrating an example of the mechanism of the door which can be opened and closed of a hinged door type. It is a schematic diagram which shows an example of a structure of the fuel cell power generation system of this invention. It is a schematic diagram which shows the other structural example of the fuel cell power generation system of this invention. It is a schematic diagram which shows the other structural example of the fuel cell power generation system of this invention. It is a schematic diagram which shows the other structural example of the fuel cell power generation system of this invention. It is sectional drawing which shows typically the principal part of an example of the fuel cell which concerns on the fuel cell power generation system of this invention. It is a schematic diagram which shows an example of the hydrogen supply apparatus applicable to the fuel cell power generation system of this invention. It is sectional drawing which shows typically the principal part of an example of the hydrogen removal apparatus applicable to the fuel cell power generation system of this invention. It is a flowchart which shows an example of the control procedure of opening and closing of the door which can be opened and closed in the fuel cell power generation system of this invention. It is a schematic diagram which shows the structure of the fuel cell used by the reference example. It is a graph which shows the result of a reference example. 1 is a schematic diagram showing a configuration of a fuel cell power generation system of Example 1. FIG. 6 is a graph showing results of power generation tests in the fuel cell power generation systems of Example 1 and Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Hydrogen supply apparatus 3 Hydrogen removal apparatus 9a, 9b Backflow prevention means 100 Unit cell 200 Positive electrode opening 201 Door which can be opened and closed

Claims (9)

A positive electrode having a positive electrode diffusion layer and a positive electrode catalyst layer for reducing oxygen; a negative electrode having a negative electrode diffusion layer and a negative electrode catalyst layer for oxidizing fuel; and a solid electrolyte membrane disposed between the positive electrode and the negative electrode; A plurality of unit cells, and hydrogen flow paths for supplying hydrogen to each of the plurality of unit cells, and at least some of the plurality of unit cells are electrically connected in series or in parallel. A fuel cell power generation system having a fuel cell and supplying power to an external load,
The fuel cell has a door that can be opened and closed, a positive electrode opening for introducing oxygen in the air into the positive electrode diffusion layer, and a ventilation path that connects the hydrogen flow path in the fuel cell and the outside of the fuel cell. Have
The ventilation path includes a backflow preventing means that opens the flow path only in the direction of exhausting from the hydrogen flow path in the fuel cell to the outside of the fuel cell, and external air from the outside of the fuel cell to the hydrogen flow path in the fuel cell. A fuel cell power generation system, wherein at least one of backflow prevention means for opening the flow path only in the direction in which the gas flows is installed.   The fuel cell power generation system according to claim 1, wherein the opening degree of the positive electrode opening can be adjusted by controlling opening and closing of the door that can be opened and closed.   The ventilation path has a backflow prevention means for opening the flow path only in the direction of exhausting from the hydrogen flow path in the fuel cell to the outside of the fuel cell, and outside air flows into the hydrogen flow path in the fuel cell from the outside of the fuel cell. The fuel cell power generation system according to claim 1 or 2, further comprising a backflow prevention means for opening the flow path only in the direction in which the flow is performed.   The fuel cell power generation system according to any one of claims 1 to 3, wherein a hydrogen supply device for supplying hydrogen to the fuel cell is connected to the fuel cell via a hydrogen channel.   The fuel cell power generation system according to any one of claims 1 to 4, wherein the hydrogen supply device is a hydrogen production device having a mechanism for supplying hydrogen generated by a reaction between a hydrogen generating substance and water.   6. The hydrogen generating material is at least one metal selected from the group consisting of aluminum, silicon, zinc and magnesium, and an alloy mainly composed of one or more of these elements, or a metal hydride. Fuel cell power generation system.   The hydrogen removal apparatus for removing the hydrogen in the hydrogen flow path which connects a fuel cell and a hydrogen supply apparatus between the fuel cell and the hydrogen supply apparatus is provided in any one of Claims 1-6. Fuel cell power generation system.   The hydrogen removal apparatus includes an electrode / electrolyte integrated body having a positive electrode for reducing oxygen, a negative electrode for oxidizing fuel, and a solid electrolyte membrane disposed between the positive electrode and the negative electrode. The fuel cell power generation system described.   The fuel cell power generation according to any one of claims 1 to 8, further comprising means for consuming hydrogen remaining in the fuel cell using a unit cell of the fuel cell after stopping the power supply to the external load. system.

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