JP2009140725A - Solid polymer fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer fuel cell power generation system capable of greatly suppressing voltage reduction of the fuel cell body by suppressing performance deterioration of a cell even if stopping and starting of a power generation operation are repeatedly carried out. <P>SOLUTION: When stopping the power generation operation of the fuel cell body 110, a control device 160 closes valves 101, 102 so as to stop supply of a fuel gas 1 and an oxidizing gas 2 to the fuel cell body 100. By controlling the valve 107 so as to make oxygen existing in the flow passage of the oxidizing gas 2 half or the less against hydrogen existing in a flow passage of the fuel gas 1 of the fuel cell body 110, a purge gas 5 is supplied to the fuel cell body 110, and the valves 103 to 106 are closed so as to seal the flow passages of the fuel gas 1 and the flow passage of the oxidization gas 2 of the fuel cell body 110. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polymer electrolyte fuel cell power generation system.

  A polymer electrolyte fuel cell power generation system includes a fuel gas containing hydrogen with respect to a fuel cell main body including a stack in which a plurality of cells and separators each having a polymer electrolyte membrane sandwiched between a fuel electrode and an oxidation electrode are alternately stacked. Is supplied to the fuel electrode side, and an oxidizing gas containing oxygen is supplied to the oxidizing electrode side, and hydrogen in the fuel gas and oxygen in the oxidizing gas are reacted electrochemically in the cell. , So that power can be obtained.

  In such a polymer electrolyte fuel cell power generation system, when the power generation operation is stopped, the supply of the fuel gas and the oxidizing gas to the fuel cell main body is stopped and carbon dioxide gas such as combustion exhaust gas, nitrogen gas, etc. Is fed to the fuel electrode side and the oxidation electrode side of the fuel cell body, and the fuel gas (hydrogen gas) on the fuel electrode side of the fuel cell body is supplied from the fuel electrode side to the outside of the fuel cell body. And purging the oxidation gas (oxygen gas) on the oxidation electrode side of the fuel cell main body from the oxidation electrode side to the outside of the fuel cell main body, so that the fuel electrode side and the oxidation electrode side of the fuel cell main body are By substituting with the purge gas, the performance deterioration of the cell due to the hydrogen gas and oxygen gas remaining in the fuel cell main body is suppressed.

JP-A-6-203862

  However, in the polymer electrolyte fuel cell power generation system as described above, when the power generation operation is stopped, as described above, even if the fuel electrode side and the oxidation electrode side of the fuel cell body are replaced with the purge gas, The performance deterioration of the cell could not be sufficiently suppressed, and the voltage of the fuel cell body gradually decreased as the power generation operation was repeatedly stopped and started.

  For this reason, the present invention is a solid polymer type that can suppress degradation of cell performance and greatly reduce the voltage drop of the fuel cell body even when the power generation operation is repeatedly stopped and started. An object is to provide a fuel cell power generation system.

  The solid polymer fuel cell power generation system according to the first invention for solving the above-mentioned problems is obtained by alternately laminating a plurality of cells and separators each having a solid polymer electrolyte membrane sandwiched between a fuel electrode and an oxidation electrode. A fuel cell main body comprising a stack, fuel gas supply means for supplying a fuel gas containing hydrogen to the fuel electrode side of the cells of the stack of the fuel cell main body, and the cells of the stack of the fuel cell main body In the polymer electrolyte fuel cell power generation system comprising an oxidant gas supply means for supplying an oxidant gas containing oxygen to the oxidant electrode side, the fuel gas flow path of the fuel cell body and the fuel cell body A fuel gas flow path blocking means for connecting the external fuel gas flow path so as to be cut off and sealing the fuel gas flow path of the fuel cell body; Oxidizing gas flow path blocking means for connecting the oxidizing gas flow path of the main body and the oxidizing gas flow path outside the fuel cell main body so as to be cut off and sealing the oxidizing gas flow path of the fuel cell main body And a purge gas supply means for supplying an inert purge gas to at least the oxidizing gas distribution path of the oxidizing gas distribution path and the fuel gas distribution path of the fuel cell main body, and stopping the power generation operation of the fuel cell main body The fuel gas supply means and the oxidizing gas supply means are controlled so as to stop the supply of the fuel gas and the oxidizing gas to the fuel cell main body, and the flow of the fuel gas in the fuel cell main body The purge gas supply means is configured so that the oxygen present in the flow path of the oxidizing gas is reduced to ½ or less of the hydrogen present in the path. The purge gas is supplied to the fuel cell body, and the fuel gas flow path blocking means and the oxidizing gas flow path are sealed so as to seal off the fuel gas flow path and the oxidizing gas flow path of the fuel cell body. And a control means for controlling the shut-off means.

  A polymer electrolyte fuel cell power generation system according to a second aspect of the invention is characterized in that, in the first aspect of the invention, a purge gas humidifying means for humidifying the purge gas is provided.

  The polymer electrolyte fuel cell power generation system according to a third aspect is the polymer electrolyte fuel cell power generation system according to the second aspect, wherein the purge gas humidifying means humidifies the oxidizing gas supplied from the oxidizing gas supply means to the fuel cell body. The fuel gas humidifying means for humidifying the fuel gas supplied from the gas humidifying means and the fuel gas supply means to the fuel cell main body is also used as at least the oxidizing gas humidifying means.

  In the polymer electrolyte fuel cell power generation system according to a fourth aspect of the present invention, in the second aspect of the invention, the purge gas humidification means is a temperature adjustment means for adjusting the temperature of the fuel cell body, and the control means When stopping the power generation operation of the fuel cell main body, the temperature control means is further controlled to cool the fuel cell main body.

  The polymer electrolyte fuel cell power generation system according to a fifth aspect of the present invention is the polymer electrolyte fuel cell power generation system according to any one of the first to fourth aspects, wherein the purge gas supply means is configured to supply the oxidizing gas in the stack of the fuel cell body. The purge gas is supplied only to the flow path, and the control means supplies the purge gas from the purge gas supply means to the flow path of the oxidant gas of the fuel cell main body to supply the oxidant gas of the fuel cell main body. The purge gas supply means is controlled so as to replace the inside of the flow path with the purge gas.

  According to the polymer electrolyte fuel cell power generation system according to the present invention, when the power generation operation is stopped, the fuel cell with respect to the amount of hydrogen gas in the fuel gas existing in the fuel gas flow path of the fuel cell main body. Oxygen gas remaining on the oxidation electrode side of the fuel cell body permeates to the fuel electrode side by reducing the ratio of the amount of oxygen gas in the oxidation gas existing in the flow path of the oxidation gas of the main body to 1/2 or less. However, the hydrogen gas present on the fuel electrode side and the oxygen gas are almost completely reacted to form water, and the high oxygen concentration portion formed on the fuel electrode can be significantly reduced. Even if the start is repeated, cell performance deterioration can be suppressed and voltage drop of the fuel cell main body can be greatly suppressed.

  Embodiments of a polymer electrolyte fuel cell power generation system according to the present invention will be described below with reference to the drawings, but the present invention is not limited to only the embodiments described below.

[First embodiment]
A first embodiment of a polymer electrolyte fuel cell power generation system according to the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a main part of a polymer electrolyte fuel cell power generation system.

  As shown in FIG. 1, the fuel gas inlet of the fuel cell main body 110 having a stack in which a plurality of cells and separators each having a solid polymer electrolyte membrane sandwiched between a fuel electrode and an oxidation electrode are alternately stacked contains hydrogen. A fuel gas supply source 121 for supplying the fuel gas 1 is connected. Between the fuel gas supply source 121 and the fuel gas receiving port of the fuel cell main body 110, a fuel gas humidifier that is a fuel gas humidifying means for humidifying the fuel gas 1 from the fuel gas supply source 121 with water 3. 122 is arranged. Valves 101 and 103 are interposed between the fuel gas supply source 121 and the fuel gas humidifier 122 and between the fuel gas humidifier 122 and the fuel gas inlet of the fuel cell main body 110, respectively.

  An oxidizing gas supply source 131 for supplying an oxidizing gas 2 containing oxygen is connected to the oxidizing gas inlet of the fuel cell main body 110. Between the oxidizing gas supply source 131 and the oxidizing gas inlet of the fuel cell main body 110, an oxidizing gas humidifier is an oxidizing gas humidifying means for humidifying the oxidizing gas 2 from the oxidizing gas supply source 131 with water 3. 132 is disposed. Valves 102 and 104 are interposed between the oxidizing gas supply source 131 and the oxidizing gas humidifier 132 and between the oxidizing gas humidifier 132 and the oxidizing gas inlet of the fuel cell main body 110, respectively.

  The fuel gas discharge port of the fuel cell main body 110 has a valve 105 at the inlet of a fuel gas gas-liquid separator 123 that separates and recovers water 3 from the used fuel gas 1 discharged from the fuel cell main body 110. Connected through. The outlet of the fuel gas gas-liquid separator 123 communicates with the outside of the system.

  The oxidizing gas discharge port of the fuel cell main body 110 has a valve 106 at the inlet of the gas-liquid separator 133 for oxidizing gas that separates and recovers the water 3 from the used oxidizing gas 2 discharged from the fuel cell main body 110. Connected through. The outlet of the oxidizing gas gas-liquid separator 133 communicates outside the system.

  A temperature adjustment water tank 141 for storing the temperature adjustment water 4 is connected to the temperature adjustment water receiving port of the fuel cell main body 110 via a feed pump 143. The temperature adjustment water tank 141 is provided with a temperature adjuster 142 for adjusting the temperature of the temperature adjustment water 4 in the tank 141. The temperature control water discharge port of the fuel cell main body 110 is connected to the temperature control water tank 141.

  Between the oxidizing gas humidifier 132 and the valve 104, a purge gas supply source 151 for supplying a purge gas 5 such as carbon dioxide gas such as combustion exhaust gas or nitrogen gas is provided via a mass flow meter 152 and a valve 107. It is connected.

  The mass flow meter 152 is electrically connected to an input unit of a control device 160 as control means. The valves 101 to 107, the temperature controller 142, and the feed pump 143 are electrically connected to the output unit of the control device 160, respectively. Based on a signal from the mass flow meter 152, the valves 101 to 107, the temperature controller 142, and the feed pump 143 can be controlled (details will be described later).

  In the present embodiment, the valve 101, the fuel gas supply source 121, the fuel gas humidifier 122 and the like constitute fuel gas supply means, and the valve 102, the oxidizing gas supply source 131, the oxidation gas The gas humidifier 122 or the like constitutes an oxidizing gas supply means, and the temperature regulating water tank 141, the temperature regulator 142, the feed pump 143 or the like constitutes a temperature regulating means, and the valves 103 and 105, etc. Thus, a fuel gas flow path blocking means is configured, and the valves 104, 106, etc., constitute an oxidizing gas flow path blocking means, and the valve 107, the purge gas supply source 151, the mass flow meter 152, etc., purge gas supply means, Is configured.

  Next, the operation of the polymer electrolyte fuel cell power generation system 100 according to this embodiment will be described.

  When a power generation operation start command is input to the control device 160, the control device 160, based on the command, causes the temperature control water 4 in the temperature control water tank 141 to reach a specified temperature. While controlling the temperature controller 142, the said feed pump 143 is operated so that the said temperature control water 4 in the said temperature control water tank 141 may be supplied in the said fuel cell main body 110. FIG. Accordingly, the temperature adjustment water 4 in the temperature adjustment water tank 141 circulates in the fuel cell main body 110 to adjust the temperature in the fuel cell main body 110 and then the temperature adjustment water from the fuel cell main body 110. The temperature is returned to the water tank 141, the temperature is adjusted again to the specified temperature by the temperature controller 142, and the water is supplied again.

  Further, the control device 160 opens the valves 101 to 106 based on the command (the valve 107 is in a closed state). Thus, the fuel gas 1 from the fuel gas supply source 121 is bubbled in the water 3 in the fuel gas humidifier 122 and humidified to a saturated state, and then supplied into the fuel cell main body 110, The oxidant gas 2 from the oxidant gas supply source 131 is bubbled in the water 3 in the oxidant gas humidifier 132 and humidified to a saturated state, and then supplied into the fuel cell body 110, and the fuel cell body 110 In each cell of the stack, hydrogen in the fuel gas 1 and oxygen in the oxidizing gas 2 react electrochemically, and electric power is obtained from the fuel cell main body 110.

  The spent fuel gas 1 and the oxidizing gas 2 remaining without being used for the reaction in the cell are sent from the fuel cell main body 110 together with the water 3 generated by the reaction, and the gas-liquid separator 123 is used. , 133, the water 3 is separated and recovered and then discharged out of the system for post-treatment.

  When a power generation operation is performed in this way and a power generation operation stop command is input to the control device 160, the control device 160 controls the valves 101 and 103 to close the valves 101 and 103. Thus, the supply of the gases 1 and 2 from the gas sources 121 and 131 to the fuel cell main body 110 is stopped, and the temperature controller 142 and the feed pump 143 are stopped. The feeding pump 143 is controlled to stop feeding the temperature-controlled water 4 in the temperature-controlled water tank 141 into the fuel cell main body 110.

  Subsequently, the control device 160 controls the valves 103 and 105 so as to close the valves 103 and 105 so as to seal off the flow path of the fuel gas 1 in the fuel cell main body 110 and to set the valve 107. The valve 107 is controlled so as to be opened, and the purge gas 5 is supplied from the purge gas supply source 151 to the flow path of the oxidant gas 2 in the fuel cell main body 110 to flow the oxidant gas 2 in the fuel cell main body 110. The oxidizing gas 2 is purged from the path.

  In this way, the purge gas 5 is supplied at a predetermined flow rate to the flow path of the oxidizing gas 2 in the fuel cell body 110, and the flow path of the oxidizing gas 2 of the fuel cell body 110 is replaced with the purge gas 5. In the oxidizing gas 2 existing in the flow path of the oxidizing gas 2 of the fuel cell body 110, the amount of hydrogen gas in the fuel gas 1 existing in the flow path of the fuel gas 1 of the fuel cell body 110 When the ratio of the amount of oxygen gas becomes ½ or less, the control device 160, based on the signal from the mass flow meter 152, closes the valves 104, 106, 107 so as to close the valves 104, 106, 107. 107, the supply of the purge gas 5 from the purge gas supply source 151 is stopped, and the flow path of the oxidizing gas 2 in the fuel cell main body 110 is closed. .

  Accordingly, the fuel cell main body 110 has an atmosphere of the fuel gas 1 in the flow path of the fuel gas 1 and an atmosphere of the purge gas 5 in the flow path of the oxidizing gas 2, that is, the flow of the fuel gas 1. The ratio of the amount of oxygen gas in the oxidizing gas 2 existing in the flow path of the oxidizing gas 2 to the amount of hydrogen gas in the fuel gas 1 existing in the path becomes 1/2 or less, in other words, The ratio of the amount of hydrogen gas in the fuel gas 1 existing in the flow path of the fuel gas 1 is more than twice the amount of oxygen gas in the flow of oxidizing gas 2 present in the flow path of the oxidizing gas 2. Thus, the power generation operation is stopped.

  Then, when a power generation operation start command is input to the control device 160, the power generation operation is performed again in the same manner as described above. Hereinafter, by repeating the above-described operation, the power generation operation is repeatedly stopped and started.

  Here, when the power generation operation is stopped, the flow path of the oxidizing gas 2 of the fuel cell main body 110 is replaced with the purge gas 5, and the flow path of the fuel gas 1 remains in the atmosphere of the fuel gas 1. The amount of hydrogen gas in the fuel gas 1 existing in the flow path of the fuel gas 1 of the fuel cell main body 110 with respect to the amount of hydrogen gas in the flow path of the oxidant gas 2 in the fuel cell main body 110 The ratio of the oxygen gas amount of the fuel cell main body 110 is equal to or less than ½, in other words, with respect to the oxygen gas amount in the oxidizing gas 2 existing in the flow path of the oxidizing gas 2 of the fuel cell main body 110. Since the ratio of the amount of hydrogen gas in the fuel gas 1 existing in the flow path of the fuel gas 1 is more than doubled, when the power generation operation is restarted, the cell of the stack of the fuel cell main body 110 Poor performance It can be significantly suppressed.

  The reason for this is not exactly clear, but can be considered as follows.

  When the fuel cell 1 is stopped in a state where the fuel gas 1 (hydrogen gas) exists in the flow path of the fuel gas 1 of the fuel cell main body 110 and the oxidizing gas 2 (oxygen gas) exists in the flow path of the oxidizing gas 1 The oxidizing gas 2 (oxygen gas) gradually permeates the cell oxidizing electrode and the solid polymer electrolyte membrane to reach the fuel electrode, and most of the gas passes through the hydrogen gas and the catalyst on the fuel electrode side. While coming into contact with water, it is considered that a part that did not come into contact with the hydrogen gas remains in the fuel electrode as it is to form a high oxygen concentration portion.

  On the other hand, as in the case of the oxidizing gas 2 (oxygen gas), the fuel gas 1 (hydrogen gas) gradually permeates through the fuel electrode and the solid polymer electrolyte membrane of the cell and reaches the oxidizing electrode. It is considered that the portion comes into contact with the oxygen gas on the oxidation electrode side via the catalyst to become water, while the portion not in contact with the oxygen gas remains as it is on the oxidation electrode to form a high hydrogen concentration portion. .

  When the power generation operation is resumed in such a state and the operating conditions are adjusted, the fuel electrode body 110 has an open circuit voltage (OCV) Vc (for example, about 1 V) between the cells in the stack. A potential difference ΔV1 (for example, about 0.3 V) is generated between the high oxygen concentration portion and another portion (high hydrogen concentration portion) of the fuel electrode, and the high oxygen concentration portion of the fuel electrode becomes the other portion of the fuel electrode. It is considered that it becomes higher than the potential (standard potential Vs: 0 V) of (high hydrogen concentration portion).

  On the other hand, a potential difference ΔV2 (for example, about 0.3 V) also occurs between the high hydrogen concentration portion of the oxygen electrode and another portion (high oxygen concentration portion), and the high hydrogen concentration portion of the oxidation electrode It is considered that it becomes lower than the potential (for example, about 1 V) of the other part of the pole (high oxygen concentration part).

  For this reason, the portion of the oxidation electrode facing the high oxygen concentration portion of the fuel electrode has a magnitude that is increased by the potential difference ΔV1 (for example, about 0.3 V) from the open circuit voltage Vc (for example, about 1 V). It is considered that the voltage is Vc + ΔV1 (for example, about 1.3V).

  On the other hand, the portion of the fuel electrode that faces the high hydrogen concentration portion of the oxidation electrode has a voltage Vs−ΔV2 (a voltage Vs−ΔV2) that is lower than the standard potential Vs (0 V) by the potential difference ΔV2 (for example, about 0.3 V). For example, it is considered to be about −0.3V).

  When such a state occurs, the contained carbon reacts with water and decomposes into carbon dioxide in the excess voltage portion, that is, the high voltage portion (for example, about 1.3 V) of the oxidation electrode, It is considered that the cell deteriorates in performance due to potential corrosion such as ionization and elution of the contained catalyst (for example, Pt or the like).

  Therefore, conventionally, as described in the background art, purge gas is supplied to the fuel electrode side and the oxidation electrode side of the fuel cell body, and the fuel gas (hydrogen gas) on the fuel electrode side of the fuel cell body is used as the fuel. Purging from the pole side to the outside of the fuel cell body and purging oxidizing gas (oxygen gas) on the oxidation electrode side of the fuel cell body from the oxidation electrode side to the outside of the fuel cell body, By replacing the fuel electrode side and the oxidation electrode side with the purge gas, the performance deterioration of the cell due to the hydrogen gas and oxygen gas remaining in the fuel cell main body is suppressed.

  However, as described above, even if the fuel electrode side and the oxidation electrode side of the fuel cell main body are replaced with the purge gas as described above, the performance deterioration of the cell of the fuel cell main body cannot be sufficiently suppressed, and the power generation operation is not performed. With the repetition of the stop and start, the voltage of the fuel cell body gradually decreased.

  Therefore, as a result of various studies by the present inventors, as described above, even if the fuel electrode side and the oxidation electrode side of the fuel cell body are replaced with the purge gas, all the hydrogen gas and the oxidation gas on the fuel electrode side are replaced. All the oxygen gas on the pole side is not replaced with the purge gas, and only a small part (about 1%) remains, and the remaining oxygen gas causes the problems as described above. it was thought.

  Based on this idea, as a result of further studies by the present inventors, when the power generation operation of the fuel cell main body 110 is stopped, the hydrogen present in the flow path of the fuel gas 1 of the fuel cell main body 110 is determined. The purge gas 5 is supplied into the fuel cell main body 110 so that the oxygen gas existing in the flow path of the oxidizing gas 2 is ½ or less of the gas, and the fuel gas 1 of the fuel cell main body 110 is supplied. If the distribution path and the distribution path of the oxidizing gas 2 are sealed, even if oxygen gas remaining on the oxidation electrode side of the fuel cell main body 110 permeates the fuel electrode side, hydrogen present on the fuel electrode side is present. It has been found that the high oxygen concentration portion that is formed in the fuel electrode can be significantly reduced by almost completely reacting the gas and the oxygen gas into water.

  That is, hydrogen gas and oxygen gas react at a ratio of 2: 1 to produce water, but the amount remaining in the fuel cell main body 110 is almost equal (1: 1) Therefore, in the fuel cell main body 110, there is no hydrogen gas sufficient to make all the remaining oxygen gas into water, so that a high oxygen concentration portion has been formed in the fuel electrode. Conceivable.

  On the other hand, the fuel cell is configured so that the oxygen gas present in the flow path of the oxidizing gas 2 is ½ or less of the hydrogen gas present in the flow path of the fuel gas 1 of the fuel cell body 110. When purging inside the main body 110, there is hydrogen gas in the fuel cell main body 110 so that all remaining oxygen gas becomes water, so that the high oxygen concentration portion formed in the fuel electrode can be remarkably reduced. Conceivable.

  Here, the result of the verification test performed in order to confirm the effect of the polymer electrolyte fuel cell power generation system 100 which concerns on this embodiment is shown in FIG. In FIG. 2, the horizontal axis represents the number of power generation stoppages when the stoppage and start of the power generation operation are repeated, and the vertical axis represents the number of power generation operation stoppages 300 times with respect to the initial voltage value of the fuel cell main body 110. The voltage change ratio when the change ratio of the voltage value when “1” is “−1” is shown. For comparison, the above-described conventional case (purging both fuel gas and oxidizing gas) was also performed.

  As can be seen from FIG. 2, in the conventional case, the voltage change ratio gradually increases as the number of power generation stoppages increases, whereas the polymer electrolyte fuel cell according to the present embodiment. In the power generation system 100, it was confirmed that the voltage change ratio did not change so much even if the number of power generation operation stoppages increased.

  Therefore, according to the present embodiment, even if the power generation operation is repeatedly stopped and started, cell performance deterioration can be suppressed, and the voltage drop of the fuel cell main body 110 can be significantly suppressed.

[Second Embodiment]
A second embodiment of the polymer electrolyte fuel cell power generation system according to the present invention will be described with reference to FIG. FIG. 3 is a schematic configuration diagram of a main part of the polymer electrolyte fuel cell power generation system. In addition, about the part similar to 1st embodiment mentioned above, by using the code | symbol similar to the code | symbol used in description of 1st embodiment mentioned above, in 1st embodiment mentioned above, A description overlapping with the description is omitted.

  As shown in FIG. 3, the purge gas supply source 151 is connected between the valve 102 and the oxidizing gas humidifier 132 via the mass flow meter 152 and the valve 107.

  In the present embodiment, the oxidizing gas humidifier 132 and the like are configured to serve not only as the oxidizing gas humidifying means but also as the purge gas humidifying means.

  In such a polymer electrolyte fuel cell power generation system 200 according to this embodiment, a power generation operation can be performed by operating in the same manner as in the case of the first embodiment described above.

  As in the case of the first embodiment described above, when a command for stopping the power generation operation is input to the control device 160, the control device 160 is the same as in the case of the first embodiment described above. In addition, the valves 101 and 103 are controlled so as to close the valves 101 and 103 to stop the supply of the gases 1 and 2 from the gas sources 121 and 131 to the fuel cell main body 110, and the temperature The temperature regulator 142 and the feed pump 143 are controlled so as to stop the regulator 142 and the feed pump 143, and the temperature regulation water 4 in the temperature regulation water tank 141 is inside the fuel cell main body 110. Stop sending to.

  Subsequently, as in the case of the first embodiment described above, the control device 160 controls the valves 103 and 105 so as to close the valves 103 and 105, so that the fuel in the fuel cell main body 110 is controlled. The valve 107 is controlled so that the flow path of the gas 1 is closed and the valve 107 is opened. Accordingly, the purge gas 5 is supplied from the purge gas supply source 151 to the oxidizing gas humidifier 132 and is humidified to a saturated state, and then supplied to the flow path of the oxidizing gas 2 in the fuel cell main body 110. The oxidizing gas 2 is purged from the flow path of the oxidizing gas 2 in the fuel cell main body 110.

  In this way, the purge gas 5 humidified to the saturated state is supplied to the flow path of the oxidizing gas 2 in the fuel cell main body 110 to a predetermined flow rate, and the flow path of the oxidizing gas 2 of the fuel cell main body 110 is saturated. When the purge gas 5 is humidified until the control device 160 is replaced with the valves 104, 106, 107 based on the signal from the mass flow meter 152, as in the first embodiment. The valves 104, 106, and 107 are controlled so as to be closed, and the supply of the purge gas 5 from the purge gas supply source 151 is stopped, and the flow path of the oxidizing gas 2 in the fuel cell main body 110 is closed.

  As a result, the fuel cell main body 110 has an atmosphere of the fuel gas 1 in the flow path of the fuel gas 1 and an atmosphere of the purge gas 5 humidified to a saturated state in the flow path of the oxidizing gas 2, The power generation operation is stopped.

  That is, in the polymer electrolyte fuel cell power generation system 100 according to the first embodiment described above, the inside of the flow path of the oxidizing gas 2 of the fuel cell main body 110 is purged with the dry purge gas 5. In the polymer electrolyte fuel cell power generation system 200 according to the embodiment, the inside of the flow path of the oxidizing gas 2 of the fuel cell main body 110 is purged with the purge gas 5 humidified to a saturated state.

  For this reason, in the polymer electrolyte fuel cell power generation system 200 according to the present embodiment, drying of the polymer electrolyte membrane of the cells of the stack of the fuel cell main body 110 during power generation operation stop can be suppressed. .

  Therefore, according to this embodiment, it is possible to obtain the same effect as in the case of the first embodiment described above, and also when restarting operation than in the case of the first embodiment described above. Can be rapidly performed, and deterioration of the solid polymer electrolyte membrane of the cell can be more reliably suppressed.

[Third embodiment]
A third embodiment of the polymer electrolyte fuel cell power generation system according to the present invention will be described with reference to FIG. FIG. 4 is a schematic configuration diagram of a main part of the polymer electrolyte fuel cell power generation system. In addition, about the part similar to 1st, 2nd embodiment mentioned above, by using the code | symbol similar to the code | symbol used in description of 1st, 2nd embodiment mentioned above, 1st, 2nd mentioned above. Description overlapping with that in the second embodiment is omitted.

  As shown in FIG. 4, the mass flow meter 152 is electrically connected to an input unit of a control device 360 that is a control means. The valves 101 to 107, the temperature controller 142, and the feed pump 143 are electrically connected to the output unit of the control device 360, respectively. Based on a signal from the mass flow meter 152, the valves 101 to 107, the temperature controller 142, and the feed pump 143 can be controlled (details will be described later).

  In the present embodiment, the temperature adjusting water tank 141, the temperature adjuster 142, the feed pump 143 and the like are configured not only as a temperature adjusting means but also as a purge gas humidifying means.

  In such a polymer electrolyte fuel cell power generation system 300 according to this embodiment, a power generation operation can be performed by operating in the same manner as in the first and second embodiments described above.

  Then, as in the case of the first and second embodiments described above, when a command to stop the power generation operation is input to the control device 360, the control device 360 is the case of the first embodiment described above. Similarly, the valves 101 and 103 are controlled so as to close the valves 101 and 103, and the supply of the gases 1 and 2 from the gas sources 121 and 131 to the fuel cell main body 110 is stopped. Then, the control device 360 controls the temperature controller 142 so as to lower the temperature adjustment water 4 in the temperature adjustment water tank 141 to room temperature, so that the inside of the fuel cell main body 110 is rapidly brought to room temperature. To lower.

  Subsequently, as in the case of the first embodiment described above, the control device 360 controls the valves 103 and 105 so as to close the valves 103 and 105, so that the fuel in the fuel cell main body 110 is controlled. The valve 1 is controlled so as to close the flow path of the gas 1 and the valve 107 is opened, and the purge gas 5 is supplied from the purge gas supply source 151 to the flow path of the oxidizing gas 2 in the fuel cell main body 110. Then, the oxidizing gas 2 is purged from the flow path of the oxidizing gas 2 in the fuel cell main body 110.

  At this time, the fuel cell main body 110 is rapidly cooled down to room temperature by the temperature adjustment water 4, so that the internal saturated vapor pressure is lowered and the purge gas 5 is humidified.

  In this way, when the purge gas 5 is supplied to the flow path of the oxidizing gas 2 in the fuel cell body 110 at a predetermined flow rate and the inside of the flow path of the oxidizing gas 2 of the fuel cell body 110 is replaced with the purge gas 5. In the same manner as in the first embodiment described above, the control device 160 closes the valves 104, 106, 107 so as to close the valves 104, 106, 107 based on the signal from the mass flow meter 152. 107, the supply of the purge gas 5 from the purge gas supply source 151 is stopped, and the flow path of the oxidizing gas 2 in the fuel cell main body 110 is closed, and then the temperature controller 142 and the feed The temperature controller 142 and the feed pump 143 are controlled so as to stop the pump 143, and the fuel of the temperature control water 4 in the temperature control water tank 141 is controlled. Stopping feeding of the pond body 110.

  As a result, the fuel cell main body 110 has an atmosphere of the fuel gas 1 in the flow path of the fuel gas 1 and an atmosphere of the purge gas 5 humidified to a saturated state in the flow path of the oxidizing gas 2, The power generation operation is stopped.

  That is, in the polymer electrolyte fuel cell power generation system 200 according to the second embodiment described above, the purge gas 5 is humidified by the oxidizing gas humidifier 132 and then supplied into the fuel cell main body 110. However, in the polymer electrolyte fuel cell power generation system 300 according to the present embodiment, the purge gas in the fuel cell main body 110 is rapidly cooled to the room temperature with the temperature-controlled water 4 in the fuel cell main body 110. 5 was humidified.

  Therefore, according to the present embodiment, it is possible to obtain the same effect as that of the first embodiment described above, and it is possible to obtain the same effect as that of the second embodiment described above.

[Other Embodiments]
In each of the above-described embodiments, the inside of the flow path of the oxidizing gas 2 of the fuel cell body 110 is replaced with the purge gas 5 and the atmosphere of the fuel gas 1 is left in the flow path of the fuel gas 1. However, the present invention is not limited to this, and the amount of hydrogen gas in the fuel gas 1 existing in the fuel gas 1 distribution route of the fuel cell main body 110 is not limited to this. The gas 1, 2 in the stack of the fuel cell main body 110 so that the ratio of the amount of oxygen gas in the oxidizing gas 2 existing in the flow path of the oxidizing gas 2 of the fuel cell main body 110 is 1/2 or less. If the purge gas 5 is supplied to the flow path of the gas and the flow paths of the gases 1 and 2 are sealed, the same effects as those of the above-described embodiments can be exhibited.

  Specifically, as another embodiment, for example, only half of the oxidizing gas 2 in the circulation path of the oxidizing gas 2 of the fuel cell main body 110 is replaced with the purge gas 5, and the fuel gas 1 in the circulation path of the fuel gas 1 is replaced. While maintaining the atmosphere of gas 1, the flow paths of these gases 1, 2 are sealed, the inside of the flow path of the oxidizing gas 2 of the fuel cell body 110 is replaced with the purge gas 5, and the flow of the fuel gas 1 The flow path of the fuel gas 1 is replaced with the purge gas 5 so that the hydrogen gas concentration in the path is in the range of 2 to 4% (below the explosion limit value), and the flow paths of these gases 1 and 2 are sealed off. It is also possible to do so.

  However, as in the above-described embodiments, the inside of the flow path of the oxidizing gas 2 of the battery body 110 is replaced with the purge gas 5 and the atmosphere of the fuel gas 1 is left in the flow path of the fuel gas 1. If the distribution paths of these gases 1 and 2 are sealed, the above-mentioned effects can be most easily obtained most easily, which is very preferable in practice.

  In the second embodiment, the purge gas 5 is humidified by connecting a purge gas supply source 151 between the valve 102 and the oxidizing gas humidifier 132 via the mass flow meter 152 and the valve 107. Thus, the fuel cell main body 110 is supplied to the oxidation electrode side, that is, both the oxidizing gas humidifying means and the purge gas humidifying means. However, as another embodiment, for example, a purge gas supply source 151 and a fuel cell It is also possible to separately provide a purge gas humidifier between the main body 110 and the oxidizing gas inlet, that is, to separately provide the oxidizing gas humidifying means and the purge gas humidifying means. However, as in the second embodiment described above, it is very preferable to use both the oxidizing gas humidifying means and the purge gas humidifying means because the installation space can be reduced.

  In the second embodiment described above, the purge gas 5 supplied to the oxidation electrode side of the fuel cell main body 110 is humidified. However, as another embodiment, for example, the humidified purge gas 5 is used as the fuel cell main body 110. When the fuel gas is supplied also to the fuel electrode side, the purge gas supply source 151 is connected between the valve 101 and the fuel gas humidifier 122 via a mass flow meter, a valve, or the like. However, it is possible to cope with this by also serving as a purge gas humidifying means.

  At this time, similarly to the above, a purge gas humidifier is separately provided between the purge gas supply source 151 and the fuel gas inlet of the fuel cell main body 110, that is, a fuel gas humidifier and a purge gas humidifier are separately provided. It is also possible. In this case, when the purge gas 5 from the purge gas supply source 151 is humidified by an independent single purge gas humidifying means and is divided and sent to the fuel gas inlet and the oxidizing gas inlet of the fuel cell main body 110, the installation is performed. This is preferable because space can be reduced. However, if the fuel gas humidifying means and the purge gas humidifying means are combined, it is very preferable because the installation space can be further reduced.

  The purge gas 5 includes combustion exhaust gas (carbon dioxide gas or mixed gas of carbon dioxide gas and nitrogen gas) generated by burning hydrocarbon fuel such as kerosene and natural gas together with air and oxygen, nitrogen gas, and the like. An inert gas such as helium gas or argon gas can be used.

  Further, as the fuel gas 1, a reformed gas obtained by reforming a hydrocarbon-based fuel such as kerosene or natural gas with water (steam reforming reaction) to be rich in hydrogen, or hydrogen gas itself can be used. As the oxidizing gas 2, air or oxygen gas itself can be used.

  The polymer electrolyte fuel cell power generation system according to the present invention can suppress the deterioration of cell performance and greatly suppress the voltage drop of the fuel cell body even if the power generation operation is repeatedly stopped and started. Therefore, it can be used extremely beneficially in the industry.

It is a schematic block diagram of the principal part of 1st embodiment of the polymer electrolyte fuel cell power generation system which concerns on this invention. It is a graph showing the result of the verification test performed in order to confirm the effect of the polymer electrolyte fuel cell power generation system which concerns on 1st embodiment. It is a schematic block diagram of the principal part of 2nd embodiment of the polymer electrolyte fuel cell power generation system which concerns on this invention. It is a schematic block diagram of the principal part of 3rd embodiment of the polymer electrolyte fuel cell power generation system which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel gas 2 Oxidizing gas 3 Water 4 Temperature control water 5 Purge gas 100 Solid polymer fuel cell power generation system 101-107 Valve | bulb 110 Fuel cell main body 121 Fuel gas supply source 122 Fuel gas humidifier 123 Fuel gas gas-liquid separator 131 Oxidant Gas Supply Source 132 Oxidizing Gas Humidifier 133 Oxidizing Gas Gas-Liquid Separator 141 Temperature Control Water Tank 142 Temperature Controller 143 Feed Pump 151 Purge Gas Supply Source 152 Mass Flow Meter 160 Controller 200 Solid Polymer Fuel Cell Power generation system 300 Polymer electrolyte fuel cell power generation system 360 Controller

Claims (5)

A fuel cell body comprising a stack in which a plurality of cells and separators alternately sandwiching a solid polymer electrolyte membrane between a fuel electrode and an oxidation electrode; and
Fuel gas supply means for supplying a fuel gas containing hydrogen to the fuel electrode side of the cell of the stack of the fuel cell body;
In the polymer electrolyte fuel cell power generation system, comprising: an oxidizing gas supply means for supplying an oxidizing gas containing oxygen to the oxidation electrode side of the cell of the stack of the fuel cell main body,
A fuel gas flow that shuts off the fuel gas flow path of the fuel cell body by connecting the flow path of the fuel gas of the fuel cell body and the flow path of the fuel gas outside the fuel cell body so as to be cut off. Route blocking means;
An oxidant gas flow that seals the oxidant gas flow path of the fuel cell body by connecting the flow path of the oxidant gas of the fuel cell body and the flow path of the oxidant gas outside the fuel cell body so as to be cut off. Route blocking means;
Purge gas supply means for supplying an inert purge gas to at least the oxidizing gas flow path of the oxidizing gas flow path and the fuel gas flow path of the fuel cell body;
When stopping the power generation operation of the fuel cell main body, the fuel gas supply means and the oxidizing gas supply means are controlled so as to stop the supply of the fuel gas and the oxidizing gas to the fuel cell main body, and The purge gas supply means is controlled so that the oxygen present in the flow path of the oxidizing gas is ½ or less of the hydrogen present in the flow path of the fuel gas of the fuel cell body. The purge gas is supplied to the fuel cell main body, and the fuel gas flow path blocking means and the oxidizing gas flow path blocking means are controlled so as to seal off the fuel gas flow path and the oxidizing gas flow path of the fuel cell main body. A solid polymer electrolyte fuel cell power generation system. In the polymer electrolyte fuel cell power generation system according to claim 1,
A solid polymer fuel cell power generation system comprising purge gas humidifying means for humidifying the purge gas. The polymer electrolyte fuel cell power generation system according to claim 2,
The purge gas humidifying means humidifies the oxidizing gas supplied from the oxidizing gas supply means to the fuel cell main body, and the fuel humidifies the fuel gas supplied from the fuel gas supply means to the fuel cell main body. A solid polymer fuel cell power generation system characterized in that at least a gas humidifying means also serves as the oxidizing gas humidifying means. The polymer electrolyte fuel cell power generation system according to claim 2,
The purge gas humidifying means is a temperature adjusting means for adjusting the temperature of the fuel cell main body;
When the control means stops the power generation operation of the fuel cell main body, the control means further controls the temperature control means so as to cool the fuel cell main body. Power generation system. In the polymer electrolyte fuel cell power generation system according to any one of claims 1 to 4,
The purge gas supply means supplies the purge gas only to the flow path of the oxidizing gas of the fuel cell main body;
The purge gas is supplied from the purge gas supply means to the oxidant gas flow path of the fuel cell body so that the purge gas replaces the oxidant gas flow path of the fuel cell body with the purge gas. A solid polymer fuel cell power generation system characterized by controlling supply means.

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