JP2011129395A - 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 making an installation space small by reducing greatly the used amount of an inert gas to be used at the shutdown of power generation operation. <P>SOLUTION: The solid polymer fuel cell power generation system 100 is provided with a control device 191 which, based on a power generation operation shutdown signal, controls to close valves 139a-139c so as to seal and cut an oxidation electrode side of a stack 111, and then, connects the stack 111 and a resistance 181 and controls to switch over a switching switch 182 so as to consume an oxygen gas 3 of the oxidation electrode side of the stack 111, and based on the information from a pressure gauge 192b, when the pressure P<SB>0</SB>of the oxidation electrode of the stack 111 becomes an oxidation electrode side specified value Po<SB>1</SB>smaller than the pressure P<SB>A</SB>of the surrounding atmosphere of the stack 111, controls to close the valves 149a-149c so as to seal and cut the fuel electrode side of the stack 111. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

A schematic configuration of a conventional polymer electrolyte fuel cell power generation system is shown in FIG.
As shown in FIG. 10, the fuel gas supply section of the stack 11 in which a plurality of cells sandwiching a solid polymer membrane having proton conductivity between a gas permeable and conductive fuel electrode and an oxidation electrode are stacked includes a fuel gas A hydrogen gas cylinder 21 for supplying the hydrogen gas 2 is connected via a pressure regulating valve 29a. A humidifier 22 for humidifying the hydrogen gas 2 is disposed between the pressure regulating valve 29a and the fuel gas supply unit of the stack 11. A connection valve 29b is interposed between the humidifier 22 and the fuel gas supply part of the stack 11.

  An oxygen gas cylinder 31 for supplying oxygen gas 3 as an oxidizing gas is connected to the oxidizing gas supply section of the stack 11 via a pressure regulating valve 39a. A humidifier 32 for humidifying the oxygen gas 3 is disposed between the pressure regulating valve 39a and the oxidizing gas supply unit of the stack 11. A connection valve 39b is interposed between the humidifier 32 and the oxidizing gas supply unit of the stack 11.

  A drain pot 23 is connected to the fuel gas discharge portion of the stack 11 via a connection valve 29c. A drain pot 33 is connected to the oxidizing gas discharge portion of the stack 11 via a connection valve 39c.

  A nitrogen gas cylinder 41 for feeding nitrogen gas 4 as an inert gas is connected between the fuel gas supply unit of the stack 11 and the connection valve 29b via a pressure regulating valve 49a. A humidifier 42 for humidifying the nitrogen gas 4 is disposed between the pressure regulating valve 49a and the fuel gas supply unit of the stack 11. A connection valve 49b is interposed between the humidifier 42 and the fuel gas supply unit of the stack 11.

  A nitrogen gas cylinder 51 is connected between the oxidizing gas supply part of the stack 11 and the connection valve 39b via a pressure regulating valve 59a. A humidifier 52 for humidifying the nitrogen gas 4 is disposed between the pressure regulating valve 59a and the oxidizing gas supply unit of the stack 11. A connection valve 59b is interposed between the humidifier 52 and the oxidizing gas supply unit of the stack 11.

Next, the operation of the conventional polymer electrolyte fuel cell power generation system 10 will be described.
When performing the power generation operation, the pressure regulating valve 29a is used to regulate the pressure, and the connection valves 29b and 29c are opened, so that the hydrogen gas 2 is sent from the hydrogen gas cylinder 21 and the water in the humidifier 22 is discharged. 1 is supplied to the fuel gas supply section of the stack 11 and is pressurized by the pressure regulating valve 39a to open the connection valves 39b and 39c. The oxygen gas 3 is sent out from the oxygen gas cylinder 31 and fed into the water 1 in the humidifier 32 and is humidified to a saturated state, and then supplied to the oxidizing gas supply unit of the stack 11. The hydrogen gas 2 and the oxygen gas 3 react electrochemically in the stack 11 to obtain electric power.

  The remaining hydrogen gas 2 that did not participate in the electrochemical reaction in the stack 11 is discharged from the fuel gas discharge portion of the stack 11 together with the excess water 1 and the like generated by the electrochemical reaction, and the drain pot 23 Then, the water 1 is removed and then reused. Further, the remaining oxygen gas 3 not involved in the electrochemical reaction in the stack 11 is discharged from the oxidizing gas discharge portion of the stack 11 together with the excess water 1 and the like generated by the electrochemical reaction, and the drain After the water 1 is removed in the pot 33, it is reused.

  When stopping the power generation operation, the valves 29a, 29b, 39a, 39b are closed, and the hydrogen gas 2 from the hydrogen gas cylinder 21 and the oxygen gas 3 from the oxygen gas cylinder 31 into the stack 11 are closed. After the supply of gas is stopped, the pressure regulating valves 49a and 59a are used to regulate the pressure, the connection valves 49b and 59b are opened, the nitrogen gas 4 is fed from the nitrogen gas cylinders 41 and 51, and the humidifiers 42, After being fed into the water 1 in the water 52 and humidified to a saturated state, the hydrogen gas 2 and the oxygen gas 3 remaining in the stack 11 are supplied to the fuel gas supply unit and the oxidizing gas supply unit of the stack 11. Is purged from the fuel gas discharge portion and the oxidizing gas discharge portion, and when the inside of the stack 11 is replaced with the nitrogen gas 4, the valves 29c, 39c, 49a, 49b, 59a, 59b are closed. By making the inside of the stack 11 an atmosphere of nitrogen gas 4 of saturated water vapor, the solid polymer accompanying an extra reaction with the remaining hydrogen gas 2 and oxygen gas 3 while preventing the solid polymer film of the cell from being dried Degradation of a catalyst or the like in the membrane or electrode is suppressed (for example, see Patent Document 1 below).

JP-A-6-251788 JP 2007-265786 A

  In the conventional polymer electrolyte fuel cell power generation system 10 as described above, after stopping the power generation operation, the hydrogen gas 2 and the oxygen gas 3 remaining in the stack 11 are purged with the nitrogen gas 4, In order to replace the inside of the stack 11 with the nitrogen gas 4, when the power generation operation is stopped, a large amount of the nitrogen gas 4 is used (about 4 to 4 times the volume of the flow path system of the gas 2 and 3 of the stack 11). 5 times), when the start and stop of the power generation operation are repeated frequently over a long period of time, the amount of nitrogen gas 4 used becomes very large, the running cost becomes high, and a large number of nitrogen gas cylinders 41 and 51 are used. It is necessary to install or to increase the capacity of the nitrogen gas cylinders 41 and 51, which requires a large installation space.

  Accordingly, the present invention provides a polymer electrolyte fuel cell power generation system that can greatly reduce the amount of inert gas used when power generation operation is stopped to reduce the installation space. With the goal.

The solid polymer fuel cell power generation system according to the first invention for solving the above-described problem is a plurality of cells in which a solid polymer film is sandwiched between a fuel electrode and an oxidation electrode and are supplied to the fuel electrode. A fuel gas supply unit and a discharge unit, and a stack having an oxidation gas supply unit and a discharge unit for supplying the fuel gas to the oxidation electrode, and the fuel gas connected to the fuel gas supply unit of the stack via a valve A fuel gas supply means for supplying the oxidizing gas supply means connected to the oxidizing gas supply section of the stack via a valve and a valve for supplying the oxidizing gas to the fuel gas discharge section of the stack A fuel gas exhaust means connected to exhaust the gas from the stack to the outside of the stack, and connected to the oxidant gas discharge section of the stack via a valve and connected to the front from the stack; An oxidizing gas exhausting means for exhausting the oxidizing gas to the outside of the stack, an oxidizing electrode side pressure measuring means for measuring the pressure on the oxidizing electrode side of the stack, and the oxidizing gas on the oxidizing electrode side of the stack are consumed. The self-consumption means for causing an electrochemical reaction between the oxidizing gas and the fuel gas inside the stack, and the supply of the oxidizing gas to the oxidation electrode side of the stack based on the power generation operation stop signal The valve of the oxidizing gas supply means is controlled to be closed, and the valve of the oxidizing gas exhaust means is controlled to be closed so as to stop the exhaust of the oxidizing gas from the oxidation electrode side of the stack. Thereafter, the self-consumption means is operated and controlled to consume the oxidation gas on the oxidation electrode side of the stack, and based on the information from the oxidation electrode side pressure measurement means, When the pressure P _O of the oxidizing electrode side of the tuck is a pressure P _A small oxidizing electrode side specified value P _O1 than the atmosphere around the stack, to stop the supply of the fuel gas to the fuel electrode side of the stack Control means for controlling the closing of the valve of the fuel gas supply means, and closing the valve of the fuel gas exhaust means so as to stop the exhaust of the fuel gas from the oxidation electrode side of the stack. It is characterized by having.

A polymer electrolyte fuel cell power generation system according to a second aspect of the invention is the first aspect of the invention, comprising a fuel electrode side pressure measuring means for measuring the pressure on the fuel electrode side of the stack, and the control means After controlling the operation of the self-consumption means so that the oxidizing gas on the oxidation electrode side of the stack is consumed, and based on information from the oxidation electrode side pressure measurement means and the fuel electrode side pressure measurement means The differential pressure between the pressure P _H on the fuel electrode side and the pressure P _O on the oxidation electrode side while making the pressure P _H on the fuel electrode side of the stack larger than the pressure P _O on the oxidation electrode side of the stack The supply of the fuel gas from the fuel gas supply means is controlled so that ΔP is equal to or less than a specified value.

The polymer electrolyte fuel cell power generation system according to a third aspect of the present invention is the solid polymer fuel cell power generation system according to the second aspect, wherein the inert gas supply means for the fuel electrode is connected to the fuel gas supply section of the stack and supplies an inert gas And the control means controls the closing of the valve of the fuel gas supply means so as to stop the supply of the fuel gas to the fuel electrode side of the stack, and from the fuel electrode side of the stack. After closing the valve of the fuel gas exhaust means so as to stop the exhaust of the fuel gas, and further, based on the information from the fuel electrode side pressure measuring means, the pressure on the fuel electrode side of the stack the P _H to the pressure P _a of the surrounding atmosphere of the stack, and characterized in that for controlling the supply of the inert gas from the inert gas supply means for the fuel electrode.

Polymer electrolyte fuel cell power generation system according to a fourth invention, in the second invention, the control means, the pressure P _O is the oxidizing electrode side specified value P _O1 of the oxidizing electrode side of the stack comprising the further based on information from the fuel electrode side pressure measuring means, the pressure P _H of the fuel electrode side of the stack so that the pressure P _a of the surrounding atmosphere of the stack, the fuel gas supply means It is characterized by controlling the supply of the fuel gas from.

A polymer electrolyte fuel cell power generation system according to a fifth aspect of the present invention includes, in the first aspect of the invention, provided with fuel electrode side pressure measuring means for measuring the pressure on the fuel electrode side of the stack, and the control means includes After controlling the operation of the self-consumption means so that the oxidizing gas on the oxidation electrode side of the stack is consumed, and based on information from the oxidation electrode side pressure measurement means and the fuel electrode side pressure measurement means , the pressure P _H of the fuel electrode side of the stack so that the pressure P _a of the surrounding atmosphere of the stack while greater than the pressure P _O of the oxidizing electrode side of the stack, from the fuel gas supply means The fuel gas supply is controlled.

The polymer electrolyte fuel cell power generation system according to a sixth aspect of the present invention is the oxidation system according to any one of the first to fifth aspects, wherein the oxidation gas is connected to the oxidizing gas supply section of the stack and supplies an inert gas. In addition to the electrode inert gas supply means, when the pressure P _O on the oxidation electrode side of the stack reaches the oxidation electrode side specified value P _O1 , the control means includes information from the oxidation electrode side pressure measurement means. based on further, those in which the pressure P _O of the oxidizing electrode side to the pressure P _a of the surrounding atmosphere of the stack, controls the supply of the inert gas from the inert gas supply means for the oxidizing electrode It is characterized by being.

The polymer electrolyte fuel cell power generation system according to a seventh aspect of the present invention is the polymer electrolyte fuel cell power generation system according to any one of the first to sixth aspects, wherein the oxidation electrode side specified value P _O1 is a saturated water vapor pressure at the stack temperature. It is characterized by being.

Polymer electrolyte fuel cell power generation system according to the 8th invention, characterized in that in any one of the seventh inventions FIRST, pressure P _A of the surrounding atmosphere of the stack, is at atmospheric pressure And

  According to the polymer electrolyte fuel cell power generation system of the present invention, the oxidation electrode side of the stack is shut off from the outside by closing the valves of the oxidation gas supply means and the oxidation gas exhaust means after the power generation operation is stopped. The hydrogen gas remaining on the oxidation electrode side of the stack is consumed by self-consumption means, that is, the hydrogen gas remaining on the oxidation electrode side of the stack is consumed by electrochemical reaction with oxygen gas in the stack. Then, after removing the hydrogen gas from the oxidation electrode side of the stack, the fuel gas supply means and the fuel gas exhaust means are closed to close the fuel electrode side of the stack. When purging the battery, the amount of inert gas used can be greatly reduced compared to the conventional method. Even when repeated, can be suppressed using amount of the inert gas significantly, it is possible to reduce the running cost, it is possible to reduce the installation space.

1 is a schematic configuration diagram of a first embodiment of a polymer electrolyte fuel cell power generation system according to the present invention. 2 is a graph showing changes in pressure on the fuel electrode side and the oxidation electrode side inside the stack when the operation of the polymer electrolyte fuel cell power generation system of FIG. 1 is stopped. It is a schematic block diagram of 2nd embodiment of the polymer electrolyte fuel cell power generation system which concerns on this invention. It is a graph which shows the pressure change by the side of the fuel electrode inside a stack at the time of operation stop of the polymer electrolyte fuel cell power generation system of FIG. It is a graph which shows the pressure change by the side of the fuel electrode inside a stack at the time of operation stop in other embodiments of the polymer electrolyte fuel cell power generation system concerning the present invention. It is a graph which shows the pressure change by the side of the fuel electrode inside a stack at the time of operation stop in other examples of a 1st embodiment of a polymer electrolyte fuel cell power generation system concerning the present invention. It is a graph which shows the pressure change by the side of the fuel electrode inside a stack at the time of operation stop in other examples of a 2nd embodiment of a polymer electrolyte fuel cell power generation system concerning the present invention. It is a graph which shows the pressure change by the side of the fuel electrode inside a stack at the time of operation stop in other examples of other embodiments of a polymer electrolyte fuel cell power generation system concerning the present invention. It is a graph which shows the pressure change by the side of the fuel electrode inside a stack at the time of the operation stop in the further another example of 1st embodiment of the polymer electrolyte fuel cell power generation system which concerns on this invention, and an oxidation electrode side. It is a schematic block diagram of an example of the conventional polymer electrolyte fuel cell power generation system.

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

[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 FIGS.

  As shown in FIG. 1, a fuel gas supply section of a stack 111 in which a plurality of cells each having a proton conductive solid polymer membrane sandwiched between a gas permeable and conductive fuel electrode and an oxidation electrode is stacked is provided with a fuel gas. A hydrogen gas cylinder 121 for supplying hydrogen gas 2 is connected via a pressure regulating valve 129a. A humidifier 122 that humidifies the hydrogen gas 2 is disposed between the pressure regulating valve 129 a and the fuel gas supply unit of the stack 111. A connection valve 129 b is interposed between the humidifier 122 and the fuel gas supply unit of the stack 111.

  An oxygen gas cylinder 131 for supplying oxygen gas 3 as an oxidizing gas is connected to the oxidizing gas supply part of the stack 111 via a pressure regulating valve 139a. A humidifier 132 for humidifying the oxygen gas 3 is disposed between the pressure regulating valve 139a and the oxidizing gas supply unit of the stack 111. A connection valve 139b is interposed between the humidifier 132 and the oxidizing gas supply unit of the stack 111.

  A drain pot 123 is connected to the fuel gas discharge portion of the stack 111 via a connection valve 129c. A drain pot 133 is connected to the oxidizing gas discharge portion of the stack 111 via a connection valve 139c.

  A nitrogen gas cylinder 141 for supplying nitrogen gas 4 as an inert gas is connected between the fuel gas supply unit of the stack 111 and the connection valve 129b via a pressure regulating valve 149a and a connection valve 149b. . A nitrogen gas cylinder 151 is connected between the oxidizing gas supply part of the stack 111 and the connection valve 139b via a pressure regulating valve 159a and a connection valve 159b.

  Various external loads L and a self-consuming resistor 181 are electrically connected to the stack 111 via a changeover switch 182, and the changeover switch 182 includes the external load L and the resistance for the stack 111. The electrical connection with 181 can be switched.

  A pressure gauge 192a, which is a fuel electrode side pressure measuring means, is disposed between the fuel gas supply section of the stack 111 and the connection valves 129b and 149b. Between the oxidizing gas supply part of the stack 111 and the connection valves 139b and 159b, a pressure gauge 192b which is an oxidation electrode side pressure measuring means is disposed. These pressure gauges 192a and 192b are electrically connected to the input unit of the control device 191 which is a control means.

  The output unit of the control device 191 is electrically connected to the valves 1129a to 129c, 139a to 139c, 149a, 149b, 159a, 159b and the changeover switch 182, and the control device 191 includes the pressure gauge 192a. , 192b and the like, the opening / closing operation of the valves 129a to 129c, 139a to 139c, 149a, 149b, 159a, 159b and the switching operation of the changeover switch 182 can be controlled. (Details will be described later).

  In the present embodiment, the hydrogen gas cylinder 121, the humidifier 122, the pressure regulating valve 129a, the connection valve 129b, and the like constitute a fuel gas supply means according to the present invention, and the oxygen gas cylinder 131, the humidifier The oxidant gas supply means according to the present invention is constituted by the vessel 132, the pressure regulating valve 139a, the connection valve 139b, etc., and the fuel gas exhaust means according to the present invention is constituted by the drain pot 123, the connection valve 129c, etc. The drain pot 133, the connection valve 139c, etc. constitute an oxidizing gas exhaust means according to the present invention, and the nitrogen gas cylinder 141, the pressure regulating valve 149a, the connection valve 149b, etc. constitute the fuel electrode according to the present invention. The inert gas supply means is used, and the nitrogen gas cylinder 151, the pressure regulating valve 159a, the connection valve 159b, etc. Configure the oxidizing electrode inert gas supply means according to the light, the resistor 181, the changeover switch 182, etc., constitute the quiescent means in accordance with the present invention.

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

When a signal to start the power generation operation is input to the control device 191, the control device 191 controls the changeover switch 182 to connect the stack 111 to the external load L, and the pressure gauge 192a. , 192b, the pressure regulating valve 129a is supplied so that the hydrogen gas 2 and the oxygen gas 3 are supplied into the stack 111 at a specified operating pressure P _D (for example, about 100 to 600 kPa (abs)). , 139a and open control of the connection valves 129b, 129c, 139b, 139c.

  Thereby, the hydrogen gas 2 delivered from the hydrogen gas cylinder 121 is supplied into the water 1 in the humidifier 122 and is humidified to a saturated state, and is supplied to the fuel gas supply unit of the stack 111. The oxygen gas 3 sent out from the oxygen gas cylinder 131 is supplied into the water 1 in the humidifier 132 and is humidified to a saturated state, and is supplied to the oxidizing gas supply unit of the stack 111, so that the hydrogen gas 2 And the oxygen gas 3 react electrochemically in the stack 111, and power can be supplied from the stack 111 to the external load L.

  Then, the remaining hydrogen gas 2 that did not participate in the electrochemical reaction in the stack 111 is discharged from the fuel gas discharge section of the stack 111 together with the excess water 1 and the like generated by the electrochemical reaction, and the drain After the water 1 is removed in the pot 123, it is reused. Further, the remaining oxygen gas 3 that did not participate in the electrochemical reaction in the stack 111 is discharged from the oxidizing gas discharge section of the stack 111 together with the excess water 1 and the like generated by the electrochemical reaction, and the drain After the water 1 is removed in the pot 133, it is reused.

  When a power generation operation stop signal is input to the control device 191 during the power generation operation, the control device 191 controls the valves 139a to 139c to close. Thus, the supply of the oxygen gas 3 from the oxygen gas cylinder 131 to the oxidation electrode side of the stack 111 is stopped, and the exhaust of the oxygen gas 3 from the oxidation electrode side of the stack 111 is stopped, whereby the stack 111 The oxidation switch side (the flow system of the oxygen gas 3) is shut off from the outside, and the changeover switch 182 is controlled to be connected so that the stack 111 is connected to the resistor 181.

  As a result, the oxygen gas 3 remaining on the oxidation electrode side of the stack 111 is consumed and reduced by causing an electrochemical reaction with the hydrogen gas 2 in the stack 111 and being consumed by the resistor 181. At the same time, as shown in FIG. 2, the pressure Po on the oxidation electrode side of the stack 111 also decreases.

Then, the control device 191, the pressure gauge 192a, based on information from 192b, while the pressure P _H of the fuel electrode side of the stack 111 is larger than the pressure P _O of the oxidizing electrode side of the stack 111 ( P _H > P _O ) The pressure difference ΔP (P _H −P _O ) between the pressure P _H on the fuel electrode side and the pressure P _O on the oxidation electrode side is set to a specified value (for example, 20 kPa (abs)) or less. In addition, the pressure control of the pressure control valve 129 a is performed to control the supply of the hydrogen gas 2 from the hydrogen gas cylinder 121.

In this way, the oxygen gas 3 on the oxidation electrode side of the stack 111 is self-consumed, and almost all (99% or more) of the oxygen gas 3 remaining on the oxidation electrode side of the stack 111 is consumed. the pressure P _a of the surrounding atmosphere of pressure P _O of the oxidizing electrode side the stack 111 (e.g., atmospheric pressure (about 100 kPa (abs))) of less oxidizing electrode side specified value P _O1 (e.g. than, the temperature of the stack 111 ( When the saturated water vapor pressure (about 1 to 50 kPa (abs)) at about 10 to 80 ° C. is reached, the control device 191 determines the fuel electrode side of the stack 111 based on information from the pressure gauges 192a and 192b. The valves 129a and 129b are controlled to be closed so that the supply of the hydrogen gas 2 from the hydrogen gas cylinder 141 to is stopped.

  Subsequently, the control device 191 supplies the nitrogen gas 4 from the nitrogen gas cylinders 131 and 141 to the fuel electrode side and the oxidation electrode side of the stack 111 based on information from the pressure gauges 192a and 192b. The pressure control valves 149a and 159a are pressure-controlled and the connection valves 149b and 159b are controlled to be opened.

The pressure P _H on the fuel electrode side and the pressure P _O on the oxidation electrode side of the stack 111 are changed to the pressure P _A (for example, atmospheric pressure (about 100 kPa (abs))) around the stack 111 by the nitrogen gas 4. The control device 191 performs the closing control of the valves 149a, 149b, 159a, 159b based on the information from the pressure gauges 192a, 192b, and controls the fuel electrode side and the oxidation electrode side of the stack 111. substituted nitrogen gas 4 at a pressure P _a of the ambient atmosphere of the stack 111 to (a nitrogen gas atmosphere of).

  That is, conventionally, after the power generation operation is stopped, the nitrogen gas 4 is supplied into the stack 11 and the hydrogen gas 2 and the oxygen gas 3 remaining in the stack 11 are purged to the outside. At the same time that the gases 2 and 3 are removed, the inside of the stack 11 is replaced with the nitrogen gas 4. However, in this embodiment, after the power generation operation is stopped, the oxidation electrode side of the stack 111 is sealed off from the outside. Thus, the oxygen gas 3 remaining on the oxidation electrode side of the stack 111 is self-consumed, that is, the oxygen gas 3 remaining on the oxidation electrode side of the stack 111 is electrochemically reacted with the hydrogen gas 2 in the stack 111 and consumed. As a result, the oxygen gas 3 is removed from the oxidation electrode side of the stack 111, and the oxidation electrode of the stack 111 accompanying self-consumption of the oxygen gas 3 is removed. The pressure of the hydrogen gas 2 supplied to the fuel electrode side of the stack 111 is also reduced in accordance with the decrease in the pressure of the stack 111, thereby removing the hydrogen gas 2 from the fuel electrode side of the stack 111 and The nitrogen gas 4 is supplied to the electrode side and the fuel electrode side so that the inside of the stack 111 is replaced with the nitrogen gas 4.

  For this reason, in the present embodiment, the amount of nitrogen gas 4 supplied into the stack 111 can be significantly reduced compared to the prior art (1 to 1 of the volume of the flow path system of the gases 2 and 3 of the stack 111). Therefore, even if the start and stop of the power generation operation are repeated frequently over a long period of time, the amount of nitrogen gas 4 used can be greatly reduced, and the running cost can be reduced. In addition, the nitrogen gas cylinders 141 and 151 can be installed in a space-saving manner.

  Therefore, according to the present embodiment, the amount of nitrogen gas 4 used when the power generation operation is stopped can be greatly reduced, and the installation space can be reduced.

  Further, it is not necessary to circulate the nitrogen gas 4 in the stack 111 to purge the hydrogen gas 2 and the oxygen gas 3, and the supply amount of the nitrogen gas 4 to the stack 111 can be suppressed to the minimum necessary amount. Even if the nitrogen gas 4 supplied to the stack 111 is not humidified, the solid polymer film of the cells of the stack 111 is not dried and deteriorated. For this reason, since the humidifiers 42 and 52 for the nitrogen gas 4 as in the prior art can be omitted, the installation space can be further reduced in size.

  In addition, since oxygen gas 3 and the like can be self-consumed without using auxiliary power such as a blower, an increase in device cost can be suppressed and power required for self-consumption can be eliminated. The power consumption of the entire system can be reduced, and the efficiency of the entire system can be increased.

Further, since the supply amount of the hydrogen gas 2 is reduced while the pressure P _H on the fuel electrode side of the stack 111 is made larger than the pressure P _O on the oxidation electrode side of the stack 111, The amount of hydrogen gas 2 on the fuel electrode side of the oxygen electrode 3 on the oxidation electrode side is not affected by changes in the volume on the fuel electrode side and the oxidation electrode side of the stack 111 due to the presence or absence of the generated water 1. Since it can be decreased while always increasing the amount, the removal of the oxygen gas 3 from the oxidation electrode side by the electrochemical reaction (2H ₂ + O ₂ → 2H ₂ O) in the stack 111 is more reliably performed. (99% or more removed), oxygen gas 3 remaining on the oxidation electrode side diffuses to the hydrogen electrode side, causing incompatibility at the start of power generation operation (high potential spots are generated locally in the cell and the catalyst To electricity It is easy to prevent the risk of causing corrosion).

[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 FIGS. However, for the same parts as those in the above-described embodiment, the same reference numerals as those used in the description of the above-described embodiment are used, thereby omitting the description overlapping with the description in the above-described embodiment.

  As shown in FIG. 3, the polymer electrolyte fuel cell power generation system 200 according to the present embodiment is the same as that of the solid polymer electrolyte fuel cell power generation system 100 according to the first embodiment described above. The fuel gas inert gas supply means such as the pressure regulating valve 149a and the connection valve 149b is omitted, and the valves 129a to 129a are based on information from the pressure gauges 192a and 192b instead of the control device 191. A control device 291 is provided as a control means for controlling the opening / closing operation of 129c, 139a to 139c, 159a, 159b and the switching operation of the changeover switch 182 (details will be described later).

  In such a polymer electrolyte fuel cell power generation system 200 according to this embodiment, when a signal to start power generation operation is input to the control device 291, the control device 291 performs the first operation described above. The same control as in the case of the polymer electrolyte fuel cell power generation system 100 according to the embodiment is performed to supply power from the stack 111 to the external load L.

  When a power generation operation stop signal is input to the control device 291 during the power generation operation in this way, the control device 291 causes the solid height according to the first embodiment described above. Control similar to that in the case of the molecular fuel cell power generation system 100 is performed to stop the supply of the oxygen gas 3 from the oxygen gas cylinder 131 to the oxidation electrode side of the stack 111, and from the oxidation electrode side of the stack 111. By stopping the exhaust of the oxygen gas 3, the oxidation switch side (circulation system of the oxygen gas 3) of the stack 111 is shut off from the outside, and the changeover switch 182 is connected so as to connect the stack 111 to the resistor 181. Is controlled.

  As a result, the oxygen gas 3 remaining on the oxidation electrode side of the stack 111 is consumed and reduced by causing an electrochemical reaction with the hydrogen gas 2 in the stack 111 and being consumed by the resistor 181. At the same time, as shown in FIG. 4, the pressure Po on the oxidation electrode side of the stack 111 also decreases.

Then, the control device 291 makes the pressure P _H on the fuel electrode side of the stack 111 larger than the pressure P _O on the oxidation electrode side of the stack 111 based on information from the pressure gauges 192a and 192b ( P _H > P _O ) The pressure regulating valve 129a is subjected to pressure regulation control so that the pressure P _A (for example, atmospheric pressure (about 100 kPa (abs))) of the ambient atmosphere of the stack 111 is set, and the hydrogen The supply of hydrogen gas 2 from the gas cylinder 121 is controlled.

In this way, the oxygen gas 3 on the oxidation electrode side of the stack 111 is self-consumed, and almost all (99% or more) of the oxygen gas 3 remaining on the oxidation electrode side of the stack 111 is consumed. temperature of the pressure P _a of the ambient atmosphere (e.g., atmospheric pressure (about 100 kPa (abs))) than smaller oxidizing electrode side specified value P _O1 (e.g., stack 111 of the pressure P _O of the oxidizing electrode side the stack 111 When the saturated water vapor pressure (about 1 to 50 kPa (abs)) at (about 10 to 80 ° C.) is reached, the control device 291 moves to the oxidation electrode side of the stack 111 based on the information from the pressure gauge 192b. The pressure control valve 159a is pressure-controlled so that the nitrogen gas 4 is supplied from the nitrogen gas cylinder 131, and the connection valve 159b is controlled to be opened.

Then, the pressure P _A of the surrounding atmosphere of the stack 111 pressure P _O of the oxidizing electrode side by a nitrogen gas 4 of the stack 111 (e.g., atmospheric pressure (about 100 kPa (abs))) and reaches the said control device 191, substituted on the basis of the information from the pressure gauge 192b, the valve 159a, and closed control 159b, the nitrogen gas 4 oxidation electrode side at a pressure P _a of the surrounding atmosphere of the stack 111 of the stack 111 ( Nitrogen gas atmosphere).

In addition, the control device 291 stops the supply of the hydrogen gas 2 from the hydrogen gas cylinder 121 to the fuel electrode side of the stack 111 based on the information from the pressure gauges 192a and 192b. By closing the valves 129a and 129b at the same time, the fuel electrode side of the stack 111 is changed to hydrogen gas 2 at the pressure P _A (for example, atmospheric pressure (about 100 kPa (abs)) of the ambient atmosphere of the stack 111. Substitution (hydrogen gas atmosphere).

That is, in the polymer electrolyte fuel cell power generation system 100 according to the first embodiment described above, the hydrogen gas 2 on the fuel electrode side of the stack 111 is reduced in accordance with the decrease of the oxygen gas 3 on the oxidation electrode side. Although the fuel electrode side supplying nitrogen gas 4 to the fuel electrode side so as to hold the atmosphere of nitrogen gas 4 in the pressure P _a, the polymer electrolyte fuel cell power generation system 200 according to this embodiment Then, the oxygen gas 3 on the oxidation electrode side is consumed while maintaining the hydrogen gas 2 on the fuel electrode side of the stack 111 at the pressure P _A , so that the fuel electrode side is maintained in the atmosphere of the hydrogen gas 2 at the pressure P _A. I kept it as it was.

  For this reason, in this embodiment, the amount of nitrogen gas 4 supplied into the stack 111 can be further reduced as compared with the case of the first embodiment described above.

  Therefore, according to the present embodiment, it is possible to obtain the same effect as that of the first embodiment described above, as well as the power generation operation than the case of the first embodiment described above. The amount of nitrogen gas 4 used at the time of stopping can be further reduced, and the installation space can be further reduced.

  Further, since the fuel electrode side of the stack 111 is held in the atmosphere of hydrogen gas 2 (reducing atmosphere), it is assumed that oxidizing gas such as oxygen in the air diffuses from outside the system to the fuel electrode side of the stack 111. In addition, it is possible to prevent deterioration of the electrode catalyst on the fuel electrode side due to the oxidizing gas.

[Other Embodiments]
In the first embodiment described above, the nitrogen gas 4 is supplied from different nitrogen gas cylinders 141 and 151 to the fuel electrode side and the oxidation electrode side of the stack 111. However, as another embodiment, For example, the nitrogen gas 4 may be supplied from the same nitrogen gas cylinder to the fuel electrode side and the oxidation electrode side of the stack 111.

  In the first embodiment described above, the pressure of the hydrogen gas 2 supplied to the fuel electrode side of the stack 111 in accordance with the pressure drop on the oxidation electrode side of the stack 111 accompanying the self-consumption of the oxygen gas 3. After the hydrogen gas 2 is removed from the fuel electrode side of the stack 111, nitrogen gas 4 is supplied to both the oxidation electrode side and the fuel electrode side of the stack 111, and the oxidation electrode of the stack 111 is supplied. Both the side and the fuel electrode side are in the atmosphere of the nitrogen gas 4, but as another embodiment, for example, according to the pressure drop on the oxidation electrode side of the stack 111 accompanying the self-consumption of the oxygen gas 3, The pressure of the hydrogen gas 2 supplied to the fuel electrode side of the stack 111 is also reduced to remove the hydrogen gas 2 from the fuel electrode side of the stack 111, and then the nitrogen gas is added to the oxidation electrode side of the stack 111. The gas 4 is fed to make the oxidation electrode side of the stack 111 the atmosphere of the nitrogen gas 4, while the hydrogen gas 2 is fed to the fuel electrode side of the stack 111 and the fuel electrode side of the stack 111 is hydrogen gas It is also possible to make the atmosphere of 2.

In the second embodiment described above, the oxygen gas 3 remaining on the oxidation electrode side of the stack 111 is reduced by causing an electrochemical reaction with the hydrogen gas 2 in the stack 111 and self-consuming. in, as shown in FIG. 4, to adjust the supply of hydrogen gas 2 of the pressure P _H of the fuel electrode side of the stack 111 from a hydrogen gas cylinder 121 to the pressure P _a of the surrounding atmosphere of the stack 111 However, as another embodiment, for example, as shown in FIG. 5, the oxygen gas 3 remaining on the oxidation electrode side of the stack 111 is allowed to cause an electrochemical reaction with the hydrogen gas 2 in the stack 111. in decreasing by quiescent, hydrogen gas 2 is supplied from a hydrogen gas cylinder 121 without directly changing the pressure P _H of the fuel electrode side of the stack 111 It is also possible to hold the intact pressure atmosphere fuel electrode side of the hydrogen gas 2 of the stack 111.

However, as in the case of the second embodiment described above, the hydrogen gas pressure P _H of the fuel electrode side of the stack 111 from a hydrogen gas cylinder 121 to the pressure P _A of the surrounding atmosphere of the stack 111 2 It is preferable from the viewpoint of safety to adjust the supply.

  In the above-described embodiment, as shown in FIGS. 2, 4, and 5, after removing the oxygen gas 3 from the oxidation electrode side of the stack 111, the nitrogen gas 4 is sent to the oxidation electrode side of the stack 111. However, as another embodiment, for example, as shown in FIGS. 6 to 8, oxygen gas is supplied from the oxidation electrode side of the stack 111. After removing 3, if the nitrogen gas 4 is sealed without being supplied to the oxidation electrode side of the stack 111, the amount of nitrogen gas used can be further reduced.

  Further, as shown in FIG. 9, after removing the hydrogen gas 2 from the fuel electrode side of the stack 111, the stack 111 is sealed without supplying the hydrogen gas 2 or nitrogen gas 4 to the oxidation electrode side of the stack 111. It is also possible to end up.

  In the above-described embodiment, the resistor 181 is connected to the stack 111 via the changeover switch 182. However, as another embodiment, for example, when many cells of the stack 111 are stacked. The resistors 181 are preferably connected to the respective cells via the changeover switch 182.

  Further, in the above-described embodiment, a self-consuming means for consuming the oxygen gas 3 remaining in the stack 111 is configured by electrically connecting the resistor 181 to the stack 111 via the changeover switch 182. However, as another embodiment, for example, the oxygen gas 3 remaining in the stack 111 is reduced by a current applying unit that applies a current to the stack 111, a voltage applying unit that applies a voltage to the stack 111, or the like. It is also possible to configure self-consuming means for consumption.

  In the above-described embodiment, the gas 2 and 3 are supplied from the gas cylinders 121 and 131 filled with the gas 2 and 3. However, as another embodiment, for example, the gas 2 and 3 are used. It is also possible to generate the gas 2 and 3 with a generator that generates the gas and feed it.

  In the above-described embodiment, the case where the nitrogen gas 4 is applied as the inert gas has been described. However, the present invention is not limited to this, and other inert gas such as helium gas or argon gas is applied. It is also possible. However, it is most preferable to apply the nitrogen gas 4 as the inert gas because the cost can be reduced most.

  Further, in the above-described embodiment, the case where the hydrogen gas 2 is applied as the fuel gas has been described. However, the present invention is not limited to this, and for example, the hydrogen gas is reformed by reforming hydrocarbons such as natural gas or kerosene. Any fuel gas containing hydrogen gas, such as those contained, can be applied in the same manner as in the above-described embodiment. However, as in the above-described embodiment, it is very preferable that the fuel gas is hydrogen gas 2 because the effects of the present invention can be obtained most significantly.

  In the above-described embodiment, the case where the oxygen gas 3 is applied as the oxidizing gas has been described. However, the present invention is not limited to this, and may be any oxidizing gas containing oxygen gas, such as air. The present invention can be applied in the same manner as in the above-described embodiment. However, it is very preferable that the oxidizing gas is the oxygen gas 3 as in the above-described embodiment because the effects of the present invention can be obtained most significantly.

  Further, the present invention is not limited to the above-described embodiment, and the above-described embodiment can be applied in appropriate combination as necessary.

  The polymer electrolyte fuel cell power generation system according to the present invention can greatly reduce the amount of inert gas used, reduce the running cost, and reduce the installation space. Can be used very beneficially.

L External load 1 Water 2 Hydrogen gas 3 Oxygen gas 4 Nitrogen gas 100 Polymer electrolyte fuel cell power generation system 111 Stack 121 Hydrogen gas cylinder 122 Humidifier 123 Drain pot 129a Pressure regulating valve 129b, 129c Connection valve 131 Oxygen gas cylinder 132 Humidifier 133 Drain pot 139a Pressure regulating valve 139b, 139c Connection valve 141, 151 Nitrogen gas cylinder 149a, 159a Pressure regulating valve 149b, 159b Connection valve 181 Resistance 182 Changeover switch 191 Controller 192a, 192b Pressure gauge 200 Solid polymer fuel cell power generation system 291 Control device

Claims (8)

A plurality of cells having a solid polymer membrane sandwiched between a fuel electrode and an oxidation electrode are stacked and have a fuel gas supply unit and a discharge unit for supplying the cell to the fuel electrode, and an oxidation gas supply unit and a discharge unit for supplying to the oxidation electrode A stack having
Fuel gas supply means connected to the fuel gas supply part of the stack via a valve to supply the fuel gas;
An oxidizing gas supply means connected to the oxidizing gas supply section of the stack via a valve to supply the oxidizing gas;
Fuel gas exhaust means connected to the fuel gas discharge portion of the stack via a valve and exhausting the gas from the stack to the outside of the stack;
An oxidizing gas exhaust means connected to the oxidizing gas discharge section of the stack via a valve and exhausting the oxidizing gas from the stack to the outside of the stack;
An oxidation electrode side pressure measuring means for measuring the pressure on the oxidation electrode side of the stack;
Self-consuming means for causing an electrochemical reaction between the oxidizing gas and the fuel gas inside the stack so as to consume the oxidizing gas on the oxidation electrode side of the stack;
Based on the power generation operation stop signal, the valve of the oxidizing gas supply means is closed to stop the supply of the oxidizing gas to the oxidizing electrode side of the stack, and from the oxidizing electrode side of the stack After controlling the closing of the valve of the oxidizing gas exhaust means to stop the exhaust of the oxidizing gas, the self-consuming means is controlled to consume the oxidizing gas on the oxidizing electrode side of the stack, Based on the information from the oxidation electrode side pressure measuring means, when the pressure P _O on the oxidation electrode side of the stack reaches the oxidation electrode side specified value P _O1 smaller than the pressure P _{A in} the ambient atmosphere of the stack, The valve of the fuel gas supply means is closed to stop the supply of the fuel gas to the fuel electrode side, and the exhaust of the fuel gas from the oxidation electrode side of the stack is stopped. And a control means for controlling the closing of the valve of the fuel gas exhaust means so as to stop. In the polymer electrolyte fuel cell power generation system according to claim 1,
Comprising fuel electrode side pressure measuring means for measuring the pressure on the fuel electrode side of the stack,
After the control means operates and controls the self-consumption means so that the oxidizing gas on the oxidation electrode side of the stack is consumed, the control means further includes the oxidation electrode side pressure measurement means and the fuel electrode side pressure measurement means. based on the information, the pressure P _O in the pressure P _H and the oxidizing electrode side of the fuel electrode side while the pressure P _H of the fuel electrode side of the stack to be larger than the pressure P _O of the oxidizing electrode side of the stack The solid polymer fuel cell power generation system is characterized in that the supply of the fuel gas from the fuel gas supply means is controlled such that the differential pressure ΔP between the fuel gas and the fuel gas is less than a specified value. The polymer electrolyte fuel cell power generation system according to claim 2,
An inert gas supply means for a fuel electrode that is connected to the fuel gas supply unit of the stack and supplies an inert gas;
The control means controls the closing of the valve of the fuel gas supply means so as to stop the supply of the fuel gas to the fuel electrode side of the stack, and the fuel gas from the fuel electrode side of the stack. After closing the valve of the fuel gas exhaust means so as to stop the exhaust of the fuel gas, the pressure P _H on the fuel electrode side of the stack is further determined based on the information from the fuel electrode side pressure measuring means. _A solid polymer fuel cell power generation system characterized in that the supply of the inert gas from the inert gas supply means for the fuel electrode is controlled so that the pressure P _{A of the} ambient atmosphere of the stack is set. . The polymer electrolyte fuel cell power generation system according to claim 2,
When the pressure P _O on the oxidation electrode side of the stack reaches the oxidation electrode side specified value P _O1 , the control means further performs the fuel electrode of the stack based on information from the fuel electrode side pressure measurement means. the pressure P _H of the side so that the pressure P _a of the surrounding atmosphere of the stack, a solid polymer electrolyte fuel cell, characterized in that for controlling the supply of the fuel gas from the fuel gas supply means Power generation system. In the polymer electrolyte fuel cell power generation system according to claim 1,
Comprising fuel electrode side pressure measuring means for measuring the pressure on the fuel electrode side of the stack,
After the control means operates and controls the self-consumption means so that the oxidizing gas on the oxidation electrode side of the stack is consumed, the control means further includes the oxidation electrode side pressure measurement means and the fuel electrode side pressure measurement means. Based on the information, the fuel PH side pressure P _H of the stack is set to be higher than the pressure P _{O of the} stack side oxidation pole side pressure P _{A in the} ambient atmosphere of the stack. A solid polymer fuel cell power generation system characterized by controlling supply of the fuel gas from a gas supply means. In the polymer electrolyte fuel cell power generation system according to any one of claims 1 to 5,
An oxidant electrode inert gas supply means for supplying an inert gas connected to the oxidant gas supply part of the stack;
When the pressure P _O on the oxidation electrode side of the stack reaches the oxidation electrode side specified value P _O1 , the control unit further determines the pressure on the oxidation electrode side based on information from the oxidation electrode side pressure measurement unit. the P _O to the pressure P _a of the surrounding atmosphere of the stack, a solid polymer electrolyte fuel, wherein the controls the supply of the inert gas from the oxidizing electrode inert gas supply means Battery power generation system. In the polymer electrolyte fuel cell power generation system according to any one of claims 1 to 6,
The oxidation pole side specified value P _O1 is a saturated water vapor pressure at the temperature of the stack. In the polymer electrolyte fuel cell power generation system according to any one of claims 1 to 7,
The pressure P _A of the surrounding atmosphere is a solid polymer fuel cell power generation system which is a large pressure of the stack.

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