JP4843909B2 - Solid polymer electrolyte fuel cell system - Google Patents

Description

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

A solid polymer electrolyte fuel cell (PEFC) uses a fluororesin polymer film having high hydrogen ion conductivity as an electrolyte. Depending on the load on the PEFC, operating conditions, and other conditions, fluorine compounds (eg, hydrofluoric acid) and fluorine ions from the electrolyte membrane may elute into the generated water generated during power generation of the fuel cell. Fluorine compounds and fluorine ions can be obtained from the metal pipe constituting the discharge path of the produced water (if the metal pipe is, for example, stainless steel (SUS), F
e (iron), Ni (nickel), Cr (chromium), etc.) is one of the factors that elute in the produced water.

As a prior art related to the present invention, there is a technique of mixing generated water with cooling water to lower the ion concentration of cooling water when the ion concentration in cooling water is high (see, for example, Patent Document 1). Further, there is a technique for passing cooling water through an ion exchanger when the ion concentration in the cooling water is high (see, for example, Patent Document 2). In addition, there is a technique for detecting a failure by measuring a fluorine ion concentration in generated water from a fuel electrode and an oxidant electrode (see, for example, Patent Document 3).
JP 2002-343390 A JP 2000-208157 A Japanese Patent Laid-Open No. 62-115670

  However, none of the above-described conventional techniques proposes to suppress the elution of ions into the generated water.

  An object of the present invention is to provide a solid polymer electrolyte fuel cell system capable of suppressing elution of ions into product water.

  The present invention adopts the following configuration in order to achieve the above-described object.

That is, the present invention relates to a solid polymer electrolyte fuel cell,
An ion detection means for detecting an ion concentration and / or an ion discharge amount contained in produced water produced by the solid polymer electrolyte fuel cell;
When the ion concentration and / or ion discharge amount detected by the ion detection means is higher than a predetermined value, the target temperature of the solid polymer electrolyte fuel cell is set to be equal to or lower than the predetermined value. The solid polymer electrolyte fuel cell system is provided with a target temperature adjusting means for lowering the target temperature in comparison with the target temperature.

  According to the present invention, when the ion concentration in the produced water and / or the ion discharge amount is higher than a predetermined value, the target temperature of the fuel cell is the target temperature when the ion concentration and / or the ion discharge amount is not more than the predetermined value. Compared to lower. Thereby, elution of ions from the solid polymer electrolyte membrane of the fuel cell is reduced.

The present invention provides a circulation path for fuel gas supplied to the solid polymer electrolyte fuel cell, part of which is composed of metal piping,
A fuel gas cooler provided in a circulation path of the fuel gas;
Fuel gas cooler control means for controlling the cooler may be further provided so that the temperature of the fuel gas containing the generated water flowing through the metal pipe is equal to or lower than a predetermined temperature.

  If it does in this way, it can control that the generated water which exists in the circulation path of fuel gas reacts with metal piping, and metal ion elutes.

Further, the present invention provides a circulation path for an oxidant gas, which is supplied to the solid polymer electrolyte fuel cell partly by metal piping,
An oxidant gas cooler provided in the circulation path of the oxidant gas;
An oxidant gas cooler control means for controlling the oxidant gas cooler so that the temperature of the oxidant gas containing the generated water flowing through the metal pipe is equal to or lower than a predetermined temperature can be further provided. .

  If it does in this way, it can control that the generated water which exists in the circulation path of oxidant gas reacts with metal piping, and metal ion elutes.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that an ion elutes in the produced water produced | generated with a solid polymer electrolyte fuel cell.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The configuration of the embodiment is an exemplification, and the present invention is not limited to the configuration of the embodiment.

[First Embodiment]
FIG. 1 is a diagram showing a configuration example of an embodiment of a solid polymer electrolyte fuel cell system according to the present invention. In FIG. 1, a solid polymer electrolyte fuel cell (hereinafter, simply referred to as “fuel cell”) 1 includes a cell stack in which a plurality of cells are stacked. Each cell is configured by sandwiching a solid polymer electrolyte membrane between a fuel electrode (hydrogen electrode) and an oxidant electrode (oxygen electrode), which are further sandwiched between a separator on the hydrogen electrode side and a separator on the oxygen electrode side. .

  The fuel electrode and the oxidant electrode each have a catalyst layer and a diffusion layer, each catalyst layer is in contact with the solid polymer electrolyte membrane, and each diffusion layer is disposed in contact with the separator. The catalyst layer has a structure in which platinum particles as a catalyst are supported on carbon particles. For example, carbon paper or carbon cloth is applied to the diffusion layer.

  The fuel cell 1 has a fuel inlet and a fuel outlet, and a fuel flow path that passes through the fuel electrode of each cell is provided between the fuel inlet and the fuel outlet. Hydrogen or a hydrogen-rich mixed gas is supplied to the fuel electrode as the fuel gas. The fuel cell 1 has an oxidant inlet and an oxidant outlet, and an oxidant flow path that passes through the oxidant electrode of each cell is provided between the oxidant inlet and the oxidant outlet. . The oxidant electrode is supplied with oxygen or a mixed gas containing oxygen, such as air, as the oxidant gas.

Hydrogen supplied to the fuel electrode is separated into protons (hydrogen ions) and electrons by an oxidation reaction in the catalyst layer constituting the fuel electrode, and the hydrogen ions move to the oxidant electrode through the solid polymer electrolyte membrane. The electrons move through the external circuit to the oxidant electrode. In the oxidant electrode, in the catalyst layer constituting the oxidant electrode, a reduction reaction is performed by oxygen, hydrogen ions, and electrons to generate water. In the oxidation and reduction reactions at the fuel electrode and the oxidant electrode, electrons (charges) passing through the external circuit are used as electric power for the load connected to the external circuit.

  The fuel cell system shown in FIG. 1 includes a fuel supply system for supplying fuel gas to the fuel electrode of the fuel cell 1, an oxidant supply system for supplying oxidant gas to the oxidant electrode, and the fuel cell 1 at a target temperature. And a cooling system that cools the fuel cell 1 for operation.

In FIG. 1, the fuel supply system includes a fuel supply device 2, a pipe 3 connecting the fuel supply device 2 and a fuel inlet provided in the fuel cell 1, a fuel outlet provided in the fuel cell 1, and a cooler 4. The pipe 5 connecting the cooler 4, the gas-liquid separator 6, the pipe 9 connecting the gas-liquid separator 6 and the circulation pump (or compressor) 8, the pump 8 and the pipe 3 are reversed. And a pipe 11 connected via a stop valve 10. At least one of the pipes 5 and 7 and the pipes 3, 9 and 11 is a pipe made of metal such as stainless steel (SUS).

  The fuel gas sent out from the fuel supply device 2 is supplied to the fuel electrode of the fuel cell 1 through the pipe 3 and used for the reaction at the fuel electrode. The fuel gas that has passed through the fuel electrode is discharged from the fuel outlet of the fuel cell 1 to the pipe 5. The fuel gas discharged to the pipe 5 is cooled as necessary by the cooler 4 and then reaches the gas-liquid separator 6 through the pipe 7. The fuel gas 6 from which the liquid layer component has been removed by the gas-liquid separator 6 is sent to the pipe 11 by the circulation pump 8 and supplied again to the fuel electrode of the fuel cell 1 through the pipe 3. In this way, a hydrogen circulation system (fuel gas circulation path) is constructed in which residual hydrogen that has not been used for the reaction at the fuel electrode contained in the fuel gas discharged from the fuel cell 1 is supplied to the fuel cell 1 again. Has been.

  In FIG. 1, the oxidant supply system includes an oxidant supply device 12, a pipe 13 connecting the oxidant supply device 12 and an oxidant inlet provided in the fuel cell 1, and an oxidation provided in the fuel cell 1. A pipe 15 connecting the agent outlet and the cooler 14, a pipe 17 connecting the cooler 14 and the gas-liquid separator 16, a pipe 19 connecting the gas-liquid separator 16 and the circulation pump (or compressor) 18, and a pump 18 and a pipe 21 that connects the pipe 13 via a check valve 20. At least one of the pipes 15 and 17 and the pipes 13, 19 and 21 is a pipe made of metal such as stainless steel (SUS).

  The oxidant gas sent out from the oxidant supply device 2 is supplied to the oxidant electrode of the fuel cell 1 through the pipe 13 and used for the reaction at the oxidant electrode. The oxidant gas that has passed through the oxidant electrode is discharged from the oxidant outlet of the fuel cell 1 to the pipe 15. The oxidant gas discharged to the pipe 15 is cooled as necessary by the cooler 14 and then reaches the gas-liquid separator 16 via the pipe 17. The oxidant gas 16 from which the liquid layer component has been removed by the gas-liquid separator 16 is sent to the pipe 21 by the circulation pump 18 and is supplied again to the oxidant electrode of the fuel cell 1 through the pipe 13. In this manner, an oxygen circulation system (oxidant gas circulation path) in which residual oxygen that has not been used for the reaction at the oxidant electrode contained in the oxidant gas discharged from the fuel cell 1 is supplied to the fuel cell 1 again. ) Is configured.

  Moreover, in FIG. 1, the cooling system of the fuel cell 1 has the following configuration. The fuel cell 1 has a cooling water inlet and a cooling water outlet, and the cooling water inlet and the cooling water outlet are connected by a cooling water passage through which the cooling water flows inside the fuel cell 1. The cooling water inlet is connected to the inlet of the circulation pump 26 via the pipe 25. The cooling water inlet is connected to an inlet of a radiator (heat exchanger) 28 that cools the cooling water via a pipe 27. The outlet of the radiator 28 is connected to the three-way valve 30 via a pipe 29. The three-way valve 30 has first and second inlets and outlets. The first inlet is connected to the outlet of the radiator 28 via a pipe 29, and the second inlet is connected to a pipe 27 ( The outlet of the fuel cell 1 is connected to the inlet of the circulation pump 26 via a pipe 32.

Thus, the cooling system of the fuel cell 1 passes through the first circulation path that circulates through the radiator 28 and the bypass pipe 31 as a passage of cooling water supplied to the fuel cell 1 by the circulation pump 26. And a second circulation path that circulates without passing through the radiator 28. The cooling system is configured such that the flow rate of the cooling water flowing through the first and second circulation paths is adjusted by a three-way valve 30 as a flow rate adjusting unit.

  The three-way valve 30 is configured using an electromagnetic valve, and the opening degree of the valve constituting the three-way valve 30 detects the temperature of the cooling water discharged from the cooling water outlet of the fuel cell 1 by the ECU 42 described later. Control is performed based on an output signal from the temperature detection sensor 33.

  By the way, in the fuel cell 1, water (product water) is generated by a reaction at the oxidant electrode. The generated water reaches the fuel electrode from the oxidant electrode through the solid polymer electrolyte membrane. Here, a fluororesin-based polymer membrane is applied to the solid polymer electrolyte membrane. For this reason, fluorine compounds (for example, hydrofluoric acid) and fluorine ions may elute in the generated water that moves to the fuel electrode.

The produced water that has reached the fuel electrode is discharged to the outside (pipe 5) of the fuel cell 1 together with the fuel gas. At this time, fluorine compounds and fluorine ions in the produced water discharged from the fuel cell 1 react with the metal constituting the pipes 5 and 7 and the like, and metal ions (if the stainless steel, each ion such as iron, nickel and chromium). Becomes a factor of elution. The elution of fluorine compounds and fluorine ions depends on the temperature of the fuel cell 1 and tends to increase as the temperature increases.

In view of the above problem, the fuel cell system shown in FIG. 1 includes an ion detection sensor 41 and an ECU (Electric Control Unit) 42 as control means. The ion detection sensor 41 includes a fluorine ion detection sensor that detects the concentration of fluorine ions in the generated water separated by the gas-liquid separator 6, a metal ion detection sensor that detects the concentration of metal ions in the generated water, and the generated water. And a flow rate detection sensor for detecting the discharge flow rate.

  The fluorine ion detection sensor detects the concentration of fluorine ions in the produced water using, for example, an ion electrode method. The metal ion detection sensor detects the metal ion concentration in the generated water using, for example, atomic absorption. Output signals of the sensors constituting the ion detection sensor 41 are given to the ECU 42.

The ECU 42 is configured using a CPU (Central Processing Unit), a memory, an input / output interface, and the like, and is generated based on the sensor output from the ion detection sensor 41 when the CPU executes a control program stored in the memory. A first ion elution reduction process in water is performed.

FIG. 2 is a flowchart showing an example of a first ion elution reduction process executed by the ECU 42. The process shown in FIG. 2 starts, for example, when the fuel cell 1 is activated. When the process shown in FIG. 2 is started, the ECU 42 initializes the target temperature of the fuel cell 1 (S01). That is, the ECU 42 detects the temperature of the fuel cell 1 so that the temperature of the fuel cell 1 becomes a target temperature initial value (for example, defined based on power generation performance, cooling performance, etc.), and thereafter the target temperature initial value is maintained. The operation of the three-way valve 30 is controlled while referring to the temperature of the cooling water obtained from 33.

  Next, the ECU 42 detects the ion concentration per unit time (S02). That is, the ECU 42 obtains the sensor output from the ion detection sensor 41 and detects the fluorine ion concentration detected by the fluorine ion detection sensor and the metal ion concentration detected by the metal ion detection sensor.

Next, the ECU 42 detects the ion discharge amount per unit time (S03). EC
U42 uses the fluorine ion concentration obtained in step S02, the metal ion concentration, and the generated water discharge amount contained in the sensor output from the ion detection sensor 41 to calculate the fluorine ion discharge amount and the metal ion discharge amount. For each.

  Next, the ECU 42 determines whether or not the ion concentration is equal to or higher than a predetermined concentration regulation value (S04). That is, the ECU 42 determines whether or not the fluorine ion concentration and the metal ion concentration are equal to or higher than the concentration specified values (corresponding to the “predetermined value” of the present invention) prepared for each. At this time, if at least one of the fluorine ion concentration and the metal ion concentration is equal to or higher than the predetermined concentration value (S04; Yes), the process proceeds to step S06. Otherwise (S04; No), the process proceeds to step S05. .

In step S05, the ECU 42 determines whether or not the ion discharge amount is equal to or greater than a predetermined discharge amount prescribed value (S05). That is, the ECU 42 determines whether or not the fluorine ion discharge amount and the metal ion discharge amount are equal to or larger than the discharge amount specified values (corresponding to the “predetermined value” of the present invention) prepared for each. At this time, if at least one of the fluorine ion discharge amount and the metal ion discharge amount is equal to or greater than the discharge amount prescribed value (S05; Yes), the process proceeds to step S06, and if not (S0
5; No), the process returns to step S02.

  In step S06, the ECU 42 changes (decreases) the target temperature of the fuel cell 1. That is, the ECU 42 gives a control signal to the radiator 28 to increase the number of rotations of the fan included in the radiator 28. If possible, the ECU 42 gives a control signal to the three-way valve 30 to increase the amount of cooling water flowing through the radiator 28. In this manner, the ECU 42 controls the operation of the radiator 28 and the three-way valve 30 so that the temperature of the cooling water is lowered and the fuel cell 1 generates power at a target temperature lower than the target temperature initial value.

The target temperature after this change is set at a temperature at which the elution of fluorine from the solid polymer electrolyte membrane can be suppressed (target temperature when the ion concentration and / or ion discharge amount is a predetermined value or less). be able to. Here, the target temperature after the change may be set so that the target temperature of the fuel cell 1 becomes a certain target temperature when the ion concentration or the discharge amount is a predetermined value or less. It may be set so that the target temperature is higher or lower than a certain target temperature in the range of the target temperature when it is equal to or lower than a predetermined value.

  In step S07, the ECU 42 determines whether or not the ion concentration (fluorine ion concentration and metal ion concentration) per unit time detected by the ion detection sensor 41 is less than the concentration specified value (S07; Yes). ), The process ends. If not (S07; No), the process proceeds to step S08.

In step S08, the ECU 42 determines whether or not the ion discharge amount (fluorine ion discharge amount and metal ion discharge amount) per unit time detected by the ion detection sensor 41 is less than the discharge amount specified value. (S08; Yes), the process ends, otherwise (S08)
No), the process returns to step S06.

  In step S06 after the second round, the process may be continued and the operation at the target temperature changed in the first S06 may be continued, and is lower than the target temperature set in the previous step S06. A target temperature may be set. That is, the target temperature may be decreased rapidly or may be decreased gradually or gradually.

When the first ion elution reduction process is completed, the ECU 42 can be configured to return the target temperature of the fuel cell 1 to the target temperature initial value. In this case, the specified values used in steps S07 and S08 are set to step S04 so that the ion concentration and the ion discharge amount do not exceed the specified values for changing the target temperature in a short time due to the temperature rise of the fuel cell 1. It is preferably set lower than the specified value used in S05. Of course, the specified values used in steps S07 and S08 may be the same as the specified values used in steps S04 and S05.

In the first ion elution reduction process as described above, the ECU 42 functions as an ion detection unit together with the ion detection sensor 41 and also functions as a target temperature adjustment unit of the fuel cell 1, and the ion concentration (fluorine ion concentration and metal ion). Concentration) and ion discharge (fluorine ion discharge and metal ion discharge) are equal to or higher than the corresponding specified values, so that the target of the fuel cell 1 is such that the ion concentration and discharge are below the specified values. Reduce the temperature (change the target temperature to a lower temperature). In other words, by changing the target temperature of the fuel cell 1 to the target temperature when the ion concentration or the discharge amount is below the specified value, the target temperature when the ion concentration or the discharge amount is higher than the specified value is changed to the ion temperature or the discharge temperature. Reduce the amount compared to the target temperature when the amount is below the specified value.

  Thereby, the temperature of the fuel cell 1 is lowered, and elution of fluorine ions and fluorine compounds from the solid polymer electrolyte membrane of the fuel cell 1 is suppressed. By suppressing the elution of fluorine ions and fluorine compounds, the amount of discharge from these fuel cells 1 is reduced, and the amount of reaction between these and the metal piping is reduced. Thereby, elution of metal ions is also suppressed. Therefore, it is possible to reduce ions contained in the generated water.

  The first ion elution reduction process can be modified as follows. That is, in the first ion elution reduction process, both the process related to the ion concentration (steps S02, S04, and S07) and the process related to the ion discharge amount (steps S03, S05, S08) are performed. However, only one of them may be performed. When the process related to the ion concentration is omitted, steps S04 and S07 in FIG. 2 are omitted.

  On the other hand, when the process related to the ion emission amount is omitted, steps S05 and S08 in FIG. 2 are omitted, and the process returns to steps S02 and S06 in the determinations of No in steps S04 and S07, respectively. The When the process related to the ion discharge amount is omitted, the flow rate detection sensor can be omitted from the ion detection sensor 41.

  Further, the first ion elution reduction process can be modified such that the target temperature is changed on condition that both the ion concentration and the ion discharge amount are equal to or higher than the specified values. In this case, for example, the process is modified so that the process returns to step S02 in the Yes determination of step S04 in FIG. Furthermore, in Yes determination of step S07, it can also deform | transform so that a process may return to step S06.

  In addition, the first ion elution reduction processing is intended for the concentration and discharge amount of fluorine ions and metal ions, but can be modified so as to target only one of fluorine ions and metal ions.

  The first ion elution reduction process is performed when the one or both of the cumulative values of the ion concentration and the ion discharge amount per unit time are equal to or more than the specified values corresponding to the cumulative values. It may be configured to reduce the temperature.

By the way, depending on the operating conditions of the fuel cell 1 such as high-load steady operation in a region where the outside air temperature is high, the cooling capacity by the cooling water is insufficient, and the temperature of the fuel cell 1 may temporarily exceed the target temperature. . The fuel cell system shown in FIG. 1 has a hydrogen circulation system in which fuel gas circulates through the fuel cell 1. When the temperature of the fuel cell 1 becomes high, the temperature of the fuel gas circulating in the hydrogen circulation system also becomes high. Then, the rate at which fluorine compounds and fluorine ions contained in the generated water in the fuel gas discharged from the fuel cell 1 react with metal pipes such as the pipes 5 and 7 constituting the hydrogen circulation system is increased. This may increase the amount of metal ions eluted per unit time.

  In view of such problems, the fuel cell system shown in FIG. 1 includes a temperature detection sensor 43 that detects the temperature of the fuel gas discharged from the fuel cell 1 and a fuel gas that cools the fuel gas discharged from the fuel cell 1. The cooler 4 as a cooler, the temperature detection sensor 44 for detecting the temperature of the fuel gas cooled by the cooler 4, and the temperature detection sensors 43 and 44 function as fuel gas cooler control means. ECU42 which controls operation | movement.

  The ECU 42 performs a second ion elution reduction process for controlling the operation of the cooler 4 based on a sensor output signal indicating the temperature of the fuel gas from the temperature detection sensors 43 and 44 by executing a program by the CPU.

  FIG. 3 is a flowchart illustrating an example of the second ion elution reduction process performed by the ECU 42. The second ion elution reduction process is started, for example, by starting the fuel cell 1. At the start of the process, the cooler 4 is in a stopped state (off state).

  When the second ion elution reduction process starts, the ECU 42 initializes the target temperature of the fuel cell 1 (S11). That is, the ECU 42 controls the three-way valve 30 so that the fuel cell 1 is operated at the target temperature initial value.

Next, the ECU 42 detects the temperature (temperature T1) of the fuel gas detected by the temperature detection sensor 43 (S12). Subsequently, the ECU 42 determines whether or not the temperature T1 is equal to or higher than a predetermined first temperature specified value (specified value 1) (S13). At this time, if the temperature T1 is not less than the specified value 1 (S13;
Yes), the ECU 42 proceeds with the process to step S14; otherwise (S13; No),
The process returns to step S12.

  In step S14, the ECU 42 gives an operation signal to the cooler 4 to place the cooler 4 in an operating state (on state). Then, the ECU 42 controls the cooler 4 so that the temperature of the fuel gas is lowered to a predetermined fuel gas target temperature.

  That is, the ECU 42 determines whether or not the temperature (temperature T2) of the fuel gas detected by the temperature detection sensor 44 is less than a predetermined second temperature specified value (specified value 2) (S15), and the temperature T2 is specified. The cooling operation by the cooler 4 is continued until the value becomes less than 2 (loop processing of S14 to S15). When the temperature T2 becomes less than the specified value 2 (S15; Yes), the cooler 4 is turned off (S16). Thereafter, the process ends.

  According to the second ion elution reduction process, the ECU 42 operates the cooler 4 to cool the fuel gas when the temperature of the fuel gas discharged from the fuel cell 1 reaches a specified value 1 or more, and Control is performed so that the temperature of the flowing fuel gas decreases to the target temperature. By reducing the temperature of the fuel gas flowing through the hydrogen circulation system, the reaction rate between the fluorine compound and fluorine ions present in the hydrogen circulation system and the metal constituting the pipes 5 and 7 can be suppressed. As a result, the amount of metal ions eluted can be reduced.

  Further, when metal ions enter the fuel cell 1 by circulation of the fuel gas, the elution amount of fluorine ions and fluorine compounds may increase. On the other hand, according to the second ion elution reduction process, since the elution of metal ions is suppressed by suppressing the reaction rate between the fluorine compound or fluorine ions and the metal, the fuel is combined with the fuel gas in which the metal ions circulate. Intrusion into the battery 1 can be suppressed.

  Note that the second ion elution reduction process is performed independently of the first ion elution reduction process. However, the process of step S11 can be made common with the process of step S01 of FIG. In FIG. 3, the second ion elution reduction process is configured to end after step S <b> 16, but then the process returns to step S <b> 12 and the loop process of steps S <b> 12 and S <b> 13 is continued. You may do it. The cooler 4 is preferably provided as close as possible to the fuel outlet of the fuel cell 1.

  In the configuration related to the first and second ion elution reduction processes described above, when the generated water generated at the oxidizer electrode moves to the fuel electrode through the solid polymer electrolyte membrane, the generated water contains a fluorine compound or fluorine. This is made by paying attention to the elution of ions. Here, it is known that hydrogen ions that move to the oxidant electrode through the solid polymer electrolyte membrane by the reaction at the fuel electrode move to the oxidant electrode together with water. Therefore, the generated water from which the fluorine compound and fluorine ions are eluted reaches the oxidant electrode, is discharged together with the oxidant gas to the outside (pipe 15) of the fuel cell 1, and reacts with the metal pipes 15 and 17 to form metal. Ions may elute. Further, as the temperature of the fuel cell 1 rises, the temperature of the oxidant gas circulating in the oxygen circulation system rises, and the reaction rate between the fluorine compound or fluorine ion and the metal (for example, the pipes 15 and 17) increases, thereby increasing the There is also a possibility that the amount of ions eluted increases.

  To solve this problem, as shown in FIG. 1, an ion detection sensor 51 that detects ions in the generated water separated by the gas-liquid separator 16 disposed in the oxygen circulation system, and an oxidant discharged from the fuel cell 1. A temperature detection sensor 53 for detecting the temperature of the gas, a cooler 14 for cooling the oxidant gas, and a temperature detection sensor 54 for detecting the temperature of the oxidant gas cooled by the cooler 4 are prepared. These can apply the same structure as the ion detection sensor 41, the cooler 4, and the temperature detection sensors 43 and 44 provided in the hydrogen circulation system. And ECU42 can be comprised so that the process similar to the 1st and 2nd ion elution reduction process mentioned above may be performed using the ion detection sensor 51, the cooler 14, and the temperature detection sensors 53 and 54. FIG.

  That is, the ECU 42 functions as an ion detection means together with the ion detection sensor 51 and functions as a target temperature adjustment means, or an oxidation that controls the operation of the cooler 14 as an oxidant gas cooler together with the temperature detection sensors 53 and 54. By functioning as agent gas cooler control means, the amount of elution of metal ions can be reduced, and metal ions can be prevented from entering the fuel cell 1 through the oxygen circulation system.

  However, in the present invention, it is not an essential requirement that both the fuel supply system and the oxidant supply system have the above-described configuration. The configuration for suppressing the reaction rate between the generated water and the metal can be provided only in one of the fuel supply system and the oxidant supply system.

  The configurations of the above-described embodiments can be appropriately combined without departing from the object of the present invention.

FIG. 1 is a diagram showing a configuration example of an embodiment of a fuel cell system according to the present invention. FIG. 2 is a flowchart showing an example of a first ion elution reduction process in the embodiment of the present invention. FIG. 3 is a flowchart showing an example of a second ion elution reduction process in the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid polymer electrolyte fuel cell 4,14 Cooler 28 Radiator 30 Three-way valve 41,51 Ion detection sensor 42 ECU
33, 43, 44, 53, 54 Temperature detection sensor

Claims (2)

A solid polymer electrolyte fuel cell;
An ion detection means for detecting an ion concentration and / or an ion discharge amount contained in produced water produced by the solid polymer electrolyte fuel cell;
When the ion concentration and / or ion discharge amount detected by the ion detection means is higher than a predetermined value, the target temperature of the solid polymer electrolyte fuel cell is set to be equal to or lower than the predetermined value. A target temperature adjusting means for lowering the target temperature in the case of
A circulation path of a fuel gas supplied to the solid polymer electrolyte fuel cell partly composed of metal piping;
A fuel gas cooler provided in a circulation path of the fuel gas;
The cooler so that the temperature of the fuel gas containing the generated water flowing through the metal pipe is equal to or lower than a predetermined temperature that suppresses the reaction rate between the ions contained in the generated water and the metal constituting the circulation path of the fuel gas . A fuel gas cooler control means for controlling
A solid polymer electrolyte fuel cell system comprising: A solid polymer electrolyte fuel cell;
An ion detection means for detecting an ion concentration and / or an ion discharge amount contained in produced water produced by the solid polymer electrolyte fuel cell;
When the ion concentration and / or ion discharge amount detected by the ion detection means is higher than a predetermined value, the target temperature of the solid polymer electrolyte fuel cell is set to be equal to or lower than the predetermined value. A target temperature adjusting means for lowering the target temperature in the case of
A circulation path of an oxidant gas supplied to the solid polymer electrolyte fuel cell, a part of which is composed of metal piping;
An oxidant gas cooler provided in the circulation path of the oxidant gas;
The temperature of the oxidant gas including the generated water flowing through the metal pipe is set to be equal to or lower than a predetermined temperature that suppresses a reaction rate between ions included in the generated water and a metal constituting the circulation path of the oxidant gas. An oxidant gas cooler control means for controlling the oxidant gas cooler;
A solid polymer electrolyte fuel cell system comprising:

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