JP2006252791A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel battery system enables precisely detect lack of cathode gas occurring at any of a plurality of unit cells constituting a fuel battery stack. <P>SOLUTION: When cathode gas is lacking at one 4A of the plurality of unit cells 4A, 4B constituting the fuel battery stack 2, anode gas is produced at a cathode of the unit cell 4a by recombination of proton transmitting from an anode 44 side and electron, and the produced anode gas is exhausted to a cathode offgas channel 16. If the anode gas is detected flowing in the cathode offgas channel 16, it is judged that the cathode gas is lacking at one of the plurality of unit cells constituting the fuel battery stack. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly to a technique for detecting a deficiency of cathode gas in a fuel cell stack.

A fuel cell is configured by sandwiching both sides of an electrolyte membrane between an electrode and a separator, and is usually used as a fuel cell stack in which a plurality of single cells are stacked with the above structure as one single cell. In the fuel cell stack composed of a plurality of single cells, even if an abnormality occurs in some of the single cells, the generated power is reduced. Patent Document 1 discloses a technique for monitoring abnormality of a fuel cell stack. According to the technique disclosed herein, the voltage of the fuel cell stack is measured, and it is determined whether the abnormality occurring in the fuel cell is flooding, gas shortage, or dry-up based on the peak shape of the measured voltage. .
JP 2004-241236 A JP-A-6-223850 JP 2004-171993 A JP 2003-331895 A

  By the way, the lack of gas which is one of the abnormalities of the fuel cell includes a lack of anode gas and a lack of cathode gas. Even if any reaction gas is deficient, the power generation performance of the fuel cell stack is reduced. However, particularly in the case of a shortage of anode gas, the components deteriorate in the cell lacking the anode gas, and the power generation performance and lifespan are reduced. There is also a problem that the characteristics are deteriorated. Therefore, when the anode gas is deficient, it is desirable to stop the operation and check the abnormal part. On the other hand, when the cathode gas is deficient, the operation can be continued by increasing the flow rate of the cathode gas in the entire stack.

  As described above, there is a difference in how to deal with gas shortage between anode gas deficiency and cathode gas deficiency. Therefore, if the generated power is reduced due to a shortage of gas in some single cells, it is accurate to determine whether it is due to a shortage of anode gas or a shortage of cathode gas in order to take appropriate measures. It is necessary to be able to make a judgment. Alternatively, it is necessary to accurately detect the deficiency of at least one of the reaction gases, for example, the cathode gas.

  The present invention has been made to solve the above-described problems, and is capable of accurately detecting the deficiency of the cathode gas occurring in some of the single cells constituting the fuel cell stack. An object of the present invention is to provide a fuel cell system.

In order to achieve the above object, a first invention is a fuel cell system,
A fuel cell stack configured by laminating a plurality of single cells each having a proton conductive electrolyte membrane;
A cathode offgas passage through which the cathode offgas discharged from the fuel cell stack flows;
Anode gas detection means for detecting the anode gas flowing through the cathode off gas passage;
When the anode gas is detected by the anode gas detection means, cathode gas deficiency determination means for determining that some of the plurality of single cells constituting the fuel cell stack are deficient in cathode gas;
It is characterized by having.

  According to a second invention, in the first invention, the anode gas detection means is a means for directly reacting the anode gas and an unreacted cathode gas contained in the cathode off gas, and detecting heat generated by the reaction. It is a feature.

  According to a third invention, in the second invention, the anode gas detection means includes a catalyst disposed in the cathode offgas passage, and the anode gas and the unreacted cathode gas contained in the cathode offgas on the catalyst. It is characterized by direct reaction.

  A fourth invention is characterized in that, in the third invention, the anode gas detection means includes a temperature sensor directly connected to the catalyst, and the temperature sensor directly detects heat generation on the catalyst. .

  According to a fifth aspect based on the third aspect, the anode gas detection means includes an upstream temperature sensor disposed upstream of the catalyst and a downstream temperature sensor disposed downstream of the catalyst. The heat generation on the catalyst is detected by the temperature difference between the temperatures respectively measured by the upstream temperature sensor and the downstream temperature sensor.

  In the first invention, when a shortage of cathode gas occurs in some of the plurality of single cells constituting the fuel cell stack, protons and electrons that have permeated from the anode side at the cathode of the single cell. Anode gas is generated by recombination, and the generated anode gas is discharged to the cathode off-gas passage. According to the first invention, by detecting the anode gas flowing through the cathode off-gas passage, it is possible to accurately detect the deficiency of the cathode gas occurring in some single cells.

  In a single cell in which cathode gas deficiency does not occur, unreacted cathode gas remains in the cathode off-gas exhausted therefrom. Therefore, when the anode gas is discharged into the cathode offgas passage due to the lack of the cathode gas in some unit cells, the anode gas and the unreacted cathode gas can be directly reacted in the cathode offgas passage. According to the second invention, the anode gas in the cathode off-gas passage can be accurately detected by detecting the heat generated by the reaction.

  According to the third invention, the anode gas and the unreacted cathode gas can be reliably reacted by using the catalyst.

  In particular, according to the fourth aspect of the invention, by directly detecting the heat generation on the catalyst by the temperature sensor, the influence of the heat generation on the electrode due to the cross leak is eliminated, and the anode gas and the unreacted cathode gas are The exotherm due to the reaction can be accurately detected.

  Further, according to the fifth aspect of the invention, by detecting the heat generation on the catalyst based on the temperature difference between the upstream temperature and the downstream temperature of the catalyst, the influence of the heat generation on the electrode due to the cross leak is eliminated, and the anode gas The exotherm due to the reaction between the unreacted cathode gas and the unreacted cathode gas can be accurately detected.

Embodiment 1 FIG.
The first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a diagram showing a schematic configuration of a fuel cell system to which the present invention is applied. As shown in this figure, the fuel cell system includes a fuel cell stack 2. The fuel cell stack 2 is configured by sandwiching a plurality of single cells 4 stacked in one direction with end plates 6A and 6B from both sides in the stacking direction. Each single cell 4 has a structure in which a proton conductive electrolyte membrane such as a solid polymer electrolyte membrane is sandwiched between a pair of catalyst electrodes (anode and cathode), and supply of anode gas containing hydrogen to the anode; Electricity is generated by supplying cathode gas containing oxygen such as air to the cathode.

  On one end plate 6A of the fuel cell stack 2, an anode gas supply pipe 10 for supplying anode gas to each single cell 4 constituting the fuel cell stack 2 and a cathode gas supply pipe for supplying cathode gas are provided. 12 is connected. The end plate 6A has an anode offgas discharge pipe 14 for discharging offgas (anode offgas) from the anode of each unit cell 4, and a cathode offgas discharge for discharging offgas (cathode offgas) from the cathode. The tube 16 is connected.

  The fuel cell system includes a detection unit 20 in the middle of the cathode offgas discharge pipe 16. In the detection unit 20, the anode gas flowing through the cathode offgas discharge pipe 16, that is, hydrogen is detected. A monitoring device 30 that monitors the state of the fuel cell stack 2 is connected to the detection unit 20. The monitoring device 30 detects the deficiency of the cathode gas occurring in some single cells among the plurality of single cells 4 constituting the fuel cell stack 2 by detecting hydrogen contained in the cathode off-gas in the detection unit 20. is doing. Hereinafter, a mechanism for detecting the deficiency of the cathode gas by the hydrogen contained in the cathode off gas will be described in detail with reference to FIG.

  FIG. 2 is a diagram schematically showing the internal structure of the fuel cell stack 2 and the phenomenon occurring therein. In FIG. 2, only two single cells 4 </ b> A and 4 </ b> B among the plurality of single cells constituting the fuel cell stack 2 are illustrated. Each single cell 4A, 4B has a structure (membrane-electrode assembly) in which the electrolyte membrane 40 is sandwiched between a cathode 42 and an anode 44, and a pair of both sides of the structure formed of a conductive material such as metal. It is configured by being sandwiched between separators 46 and 48. A gas flow path (cathode gas flow path) 50 through which the cathode gas flows is formed between the separator 46 and the cathode 42, and a gas flow path (flow through which the anode gas flows) between the separator 48 and the anode 44. Anode gas flow path) 52 is formed.

  The fuel cell stack 2 is formed with a cathode gas supply manifold 54 connected to the inlet of the cathode gas flow path 50 of each single cell 4A, 4B, and a cathode offgas discharge manifold 56 connected to the outlet thereof. The supply manifold 54 is connected to the cathode gas supply pipe 12 (shown in FIG. 1), and the cathode gas supplied from the cathode gas supply pipe 12 flows through the supply manifold 54 in the cathode gas flow of each single cell 4A, 4B. Distributed to the path 50. On the other hand, the discharge manifold 56 is connected to the cathode offgas discharge pipe 16, and the cathode offgas discharged from the cathode gas flow path 50 of each single cell 4 </ b> A, 4 </ b> B is collected in the discharge manifold 56 and is supplied to the cathode offgas discharge pipe 16. Discharged. Although not shown, an anode gas supply manifold connected to the anode gas supply pipe 10 (shown in FIG. 1) is connected to the inlet of the anode gas flow path 52 of each single cell 4A, 4B, and the anode gas flow path An anode offgas discharge manifold connected to the anode offgas discharge pipe 14 (shown in FIG. 1) is connected to the outlet 52.

  With the configuration described above, anode gas is supplied to the anode 44 of each single cell 4A, 4B, and cathode gas is supplied to the cathode 42. However, the two single cells 4A and 4B shown in FIG. 2 have different cathode gas supply states, and in the single cell 4B, the cathode gas has a flow rate sufficient for the flow rate of the anode gas supplied to the anode 44. Is supplied to the cathode 42, whereas the flow rate of the cathode gas supplied to the cathode 42 is insufficient in the other single cell 4A. In this case, the following chemical reaction occurs in each single cell 4A, 4B.

In the anodes 44 of the single cells 4A and 4B, hydrogen ions are generated when hydrogen contained in the anode gas causes a chemical reaction of the following formula (1).
H ₂ → 2H ⁺ + 2e ⁻ (1)
Hydrogen ions generated at the anode 44 are supplied to the cathode 42 through the electrolyte membrane 40. In the cathode 42, water (water vapor) is generated by causing a chemical reaction of the following formula (2) between oxygen contained in the cathode gas and hydrogen ions supplied through the electrolyte membrane 40.
4H ⁺ + 4e ⁻ + O ₂ → 2H ₂ O (2)
When each of the above reactions occurs continuously at the anode 44 and the cathode 42, a potential difference is generated between the anode 44 and the cathode 42, and the single cell functions as a battery.

  In the single cell 4B in which the flow rate of the cathode gas is sufficient, the chemical reaction of the above formula (2) occurs from the upstream side to the downstream side of the cathode gas flow channel 50. As a result, the cathode off-gas discharged from the single cell 4B to the discharge manifold 56 includes water vapor generated by the above reaction and unreacted oxygen in addition to nitrogen as an inert gas. Note that hydrogen may leak from the anode 44 side to the cathode side due to the cross leak of the electrolyte membrane 40, but the hydrogen due to the cross leak reacts with oxygen on the cathode 42 to become water. For this reason, hydrogen is not contained in the cathode off gas discharged | emitted from the single cell 4B.

On the other hand, in the single cell 4A in which the flow rate of the cathode gas is insufficient, the chemical reaction of the above formula (2) occurs on the upstream side of the cathode gas flow path 50, but the oxygen necessary for the reaction is lost on the downstream side. Therefore, on the downstream side of the cathode gas flow channel 50, hydrogen ions supplied from the anode 44 through the electrolyte membrane 40 are recombined with electrons as shown in the following formula (3), and hydrogen is generated. Become.
2H ⁺ + 2e ⁻ → H ₂ (3)
If oxygen remains in the cathode gas, the produced hydrogen burns on the cathode 42 to become water. However, since oxygen that reacts with hydrogen does not remain on the downstream side of the cathode gas flow path 50, the hydrogen generated by the above reaction is included in the cathode offgas together with nitrogen, water vapor, etc., and is discharged from the single cell 4A. The Hydrogen discharged from the single cell 4A flows through the discharge manifold 56 mixed with the cathode offgas from the other single cell 4B, and is discharged from the outlet of the fuel cell stack 2 to the cathode offgas discharge pipe 16.

  As described above, when the cathode gas is deficient in some of the plurality of single cells 4A and 4B constituting the fuel cell stack 2, the cathode off gas flowing in the cathode off gas discharge pipe 16 Will contain hydrogen. Further, since the cathode off gas does not contain hydrogen due to the cross leak of the electrolyte membrane 40, if the cathode off gas contains hydrogen, it is determined that the cathode gas is deficient in some single cells. can do. Therefore, as described above, by detecting the hydrogen flowing through the cathode offgas discharge pipe 16 by the detection unit 20, it is possible to detect the deficiency of the cathode gas occurring in some single cells.

  Various detection methods are conceivable as the hydrogen detection method. In this fuel cell system, hydrogen is detected by detecting the heat generated by the reaction between hydrogen and oxygen by utilizing the condition that hydrogen to be detected is contained in the cathode offgas. In other words, the cathode off gas contains unreacted oxygen discharged from other single cells. Therefore, this unreacted oxygen reacts with hydrogen, and the heat generated by the reaction is detected to detect the exothermic oxygen in the cathode off gas. The presence of hydrogen can be detected.

  FIG. 3 is a diagram illustrating the configuration of the detection unit 20 in detail. As shown in FIG. 3, a thermocouple 22 whose periphery is covered with a catalyst 24 is disposed in the detection unit 20. The monitoring device 30 is connected to the thermocouple 22. When the cathode off gas contains hydrogen, the hydrogen reacts with oxygen on the catalyst 24. The monitoring device 30 detects heat generated by the reaction between hydrogen and oxygen by the thermocouple 22. Specifically, the determination temperature according to the cathode gas flow rate, the anode gas flow rate, and the cooling water temperature is determined in advance. When the temperature detected by the thermocouple 22 exceeds the determination temperature, the reaction is caused by the reaction between hydrogen and oxygen. It is determined that there was a fever. In that case, the monitoring device 30 outputs an alarm signal to warn that a shortage of cathode gas occurs in some single cells. In the present fuel cell system, the monitoring device 30 functions as the “cathode gas deficiency determining means” of the first invention.

  With the configuration described above, according to the present fuel cell system, hydrogen that flows through the cathode offgas discharge pipe 16 reacts with oxygen in the cathode offgas, and heat generated by the reaction is detected, thereby occurring in some single cells. It is possible to accurately detect the deficiency of the cathode gas.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 4 is a diagram showing in detail the configuration of the detection unit 20 in the fuel cell system of the present embodiment. In the present fuel cell system, the detection unit 20 is provided with a countermeasure against condensation. Specifically, a heater 26 is provided in contact with the thermocouple 22, and a catalyst 22 is provided so as to cover the thermocouple 22 and the heater 26. A thermocouple 22 is connected to the input part of the monitoring device 30, and a heater 26 is connected to the output part. The monitoring device 30 controls the power supplied to the heater 26 so that the temperature detected by the thermocouple 22 becomes a constant temperature (100 ° C. or higher).

  A large amount of water vapor is contained in the cathode offgas flowing in the cathode offgas discharge pipe 16 due to the water generation reaction at the cathode. For this reason, when the temperature of the catalyst 24 is lower than the temperature of the cathode offgas, water vapor is condensed on the surface of the catalyst 24. Since the reaction between hydrogen and oxygen on the catalyst 24 is a gas phase reaction, the progress of the reaction is hindered when the catalyst 24 is condensed. However, according to the present fuel cell system, since the catalyst 24 is heated by the heater 26, the catalyst 24 is not condensed, and hydrogen and oxygen in the cathode offgas can be reacted reliably.

  When hydrogen and oxygen react on the catalyst 24, the power supplied to the heater 26 is reduced so as to suppress an increase in the detected temperature of the thermocouple 22 due to the reaction heat. Therefore, in this fuel cell system, it is possible to detect the presence of hydrogen from a decrease in the power supplied to the heater 26, and it is possible to detect the deficiency of the cathode gas occurring in some single cells.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a diagram showing in detail the configuration of the detection unit 20 in the fuel cell system of the present embodiment. In the fuel cell system, a pipe 66 that passes through the cathode offgas discharge pipe 16 is provided. A catalyst 60 is applied to the outer surface of the pipe 66. A fluid such as water or air is allowed to flow in the pipe 66 at a constant flow rate, and the fluid flowing in the pipe 66 is heated by the heater 70. The heating temperature of the heater 70 is set to a temperature higher than the temperature in the cathode offgas discharge pipe 16. Thermometers 62 and 64 for measuring the temperature of the fluid in the pipe 66 are provided near the inlet where the pipe 66 enters the cathode offgas discharge pipe 16 and near the outlet where the pipe 66 exits the cathode offgas discharge pipe 16. It has been. These thermometers 62 and 64 are connected to the monitoring device 30.

  According to such a configuration of the detection unit 20, when hydrogen and oxygen in the cathode offgas react on the catalyst 60, the fluid flowing in the pipe 66 is heated by the reaction heat. As a result, a temperature difference occurs between the inlet temperature detected by the inlet-side thermometer 62 and the outlet temperature detected by the outlet-side thermometer 64. Therefore, according to the present fuel cell system, it is possible to detect heat generation due to the reaction of hydrogen and oxygen from the temperature difference between the inlet temperature and the outlet temperature, and to detect the deficiency of cathode gas occurring in some single cells. be able to.

  Further, according to the present fuel cell system, the catalyst 60 can be heated by the fluid flowing in the pipe 66, so that condensation of the catalyst 60 can be prevented and hydrogen and oxygen in the cathode offgas can be reacted reliably. it can.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a diagram showing in detail the configuration of the detection unit 20 in the fuel cell system of the present embodiment. In this fuel cell system, a catalyst 60 is applied to a pipe 66 passing through the cathode offgas discharge pipe 16, and a thermocouple 68 is disposed in contact with the catalyst 60. The thermocouple 68 is connected to the monitoring device 30. A fluid heated by the heater 70 flows through the pipe 66.

  According to such a configuration of the detection unit 20, since the catalyst 60 is heated by the fluid flowing in the pipe 66, the catalyst 60 is not condensed, and hydrogen and oxygen in the cathode offgas are reliably reacted. be able to. Further, since the heat generated by the reaction between hydrogen and oxygen on the catalyst 60 can be directly detected by the thermocouple 68, the detection sensitivity to the heat generation is higher than in the case of detecting indirectly as in the third embodiment. The heat generated by the reaction between hydrogen and oxygen can be detected more accurately.

Embodiment 5. FIG.
Next, a fifth embodiment of the present invention will be described with reference to FIG.
FIG. 7 is an explanatory diagram for explaining countermeasures against dew condensation in the detection unit in the fuel cell system according to the present embodiment. In this fuel cell system, dew condensation in the detection unit 20 is prevented by pre-processing before the cathode off gas enters the detection unit 20. Specifically, a gas-liquid separator 74 is disposed upstream of the detection unit 20 in the cathode offgas discharge pipe 16, and a heat exchanger 72 is further disposed upstream thereof. The cathode off gas that passes through the heat exchanger 72 is cooled to a temperature equal to or lower than the temperature of the detection unit 20 (catalyst temperature).

  According to such a configuration, a part of the water vapor contained in the cathode off gas is liquefied in the heat exchanger 72, and the water in which the water vapor is liquefied is recovered by the gas-liquid separator 74. Thereby, the dew point of the cathode off gas when flowing into the detection unit 20 becomes lower than the temperature of the detection unit 20, and condensation in the detection unit 20 is prevented. The configuration of the detection unit 20 may be any of the configurations of the first to fourth embodiments.

Embodiment 6 FIG.
Next, a sixth embodiment of the present invention will be described with reference to FIG.
FIG. 8 is an explanatory diagram for explaining the arrangement of the detection units 20 in the fuel cell system of the present embodiment. As the configuration of the detection unit 20, any configuration of the first to fourth embodiments may be used. In the present fuel cell system, a bypass pipe 78 is provided in parallel with the cathode offgas discharge pipe 16, and the detection unit 20 is disposed in the bypass pipe 78. The bypass pipe 78 is formed of a pipe having an inner diameter smaller than that of the cathode offgas discharge pipe 16. A butterfly valve 76 is provided at the inlet side connection between the cathode offgas discharge pipe 16 and the bypass pipe 78. By operating the butterfly valve 76, the cathode off gas flow direction can be switched between the cathode off gas discharge pipe 16 and the bypass pipe 78. The butterfly valve 76 is connected to the output side of the monitoring device 30, and the monitoring device 30 operates the butterfly valve 76 at regular time intervals to flow the cathode off gas to the bypass pipe 78 side.

  According to such a configuration, only a part of the cathode off-gas discharged from the fuel cell stack can be supplied to the detection unit 20. As the flow rate of the cathode off gas passing through the detection unit 20 increases, the amount of heat carried away by the cathode off gas increases accordingly. For this reason, not only the detection sensitivity when detecting heat generation due to the reaction between hydrogen and oxygen decreases, but also when the catalyst is heated as a countermeasure against condensation as in Embodiments 2 to 4, the catalyst is kept at a high temperature. Will require a lot of energy. According to the present fuel cell system, since the flow rate of the cathode off gas passing through the detection unit 20 can be suppressed, high detection sensitivity can be ensured and the amount of energy for keeping the catalyst at a high temperature can be suppressed.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications can be made.

  In the above embodiment, hydrogen and oxygen are reacted with a catalyst, and the heat contained in the cathode is detected by detecting heat generated by the reaction. However, hydrogen may be detected using a hydrogen sensor. .

  As a method for detecting heat generation due to the reaction of hydrogen and oxygen on the catalyst, temperature sensors (thermocouples, etc.) are arranged upstream and downstream of the catalyst in the cathode offgas discharge pipe, and the temperature difference between the two temperature sensors is detected. Thus, the heat generation on the catalyst may be detected. When hydrogen leaks from the anode side to the cathode side due to cross leakage of the electrolyte membrane, hydrogen and oxygen react on the cathode to generate heat, and the temperature of the cathode offgas rises. However, according to the detection method described above, the influence of the temperature of the cathode offgas flowing into the catalyst is eliminated, so that the heat generated by the reaction between hydrogen and oxygen on the catalyst can be accurately detected.

  In addition, the method for detecting the depletion of cathode gas according to the present invention can be combined with the method for detecting the depletion of gas by detecting a decrease in voltage. According to this, it can be determined whether the lack of gas causing the voltage drop is the lack of anode gas or the lack of cathode gas, and appropriate measures can be taken. Further, when combined with the detection of the voltage for each single cell by the cell monitor, it is possible to specify a single cell in which the cathode gas is deficient.

1 is a diagram showing a schematic configuration of a fuel cell system to which the present invention is applied. It is a figure which shows typically the internal structure of a fuel cell stack, and the phenomenon which has occurred there. It is a figure which shows the structure of the detection part in Embodiment 1 of this invention in detail. It is a figure which shows the structure of the detection part in Embodiment 2 of this invention in detail. It is a figure which shows the structure of the detection part in Embodiment 3 of this invention in detail. It is a figure which shows the structure of the detection part in Embodiment 4 of this invention in detail. It is explanatory drawing for demonstrating the countermeasure against dew condensation of the detection part in Embodiment 5 of this invention. It is explanatory drawing for demonstrating arrangement | positioning of the detection part in Embodiment 6 of this invention.

Explanation of symbols

2 Fuel cell stack 4 Single cell 4A Single cell 4B in which the cathode gas is deficient Normal single cell 10 Anode gas supply pipe 12 Cathode gas supply pipe 14 Anode off gas discharge pipe 16 Cathode off gas discharge pipe 20 Detector 22 Thermocouple 24 Catalyst 26 Heater 30 Monitoring device 40 Electrolyte membrane 42 Cathode 44 Anode 46, 48 Separator 50 Cathode gas flow path 52 Anode gas flow path 54 Cathode gas supply manifold 56 Cathode off-gas discharge manifold 60 Catalyst 62, 64 Thermometer 66 Pipe 68 Thermocouple 70 Heater 72 Heat exchanger 74 Gas-liquid separator 76 Butterfly valve 78 Bypass pipe

Claims (5)

A fuel cell stack configured by laminating a plurality of single cells each having a proton conductive electrolyte membrane;
A cathode offgas passage through which the cathode offgas discharged from the fuel cell stack flows;
Anode gas detection means for detecting the anode gas flowing through the cathode off gas passage;
When the anode gas is detected by the anode gas detection means, cathode gas deficiency determination means for determining that some of the plurality of single cells constituting the fuel cell stack are deficient in cathode gas;
A fuel cell system comprising:   2. The fuel cell system according to claim 1, wherein the anode gas detection means is means for directly reacting the anode gas and an unreacted cathode gas contained in the cathode off gas and detecting heat generated by the reaction.   The said anode gas detection means contains the catalyst arrange | positioned in the said cathode off gas channel | path, The anode gas and the unreacted cathode gas contained in cathode off gas are made to react directly on the said catalyst. Fuel cell system.   4. The fuel cell system according to claim 3, wherein the anode gas detection means includes a temperature sensor directly connected to the catalyst, and the heat generation on the catalyst is directly detected by the temperature sensor. The anode gas detection means includes an upstream temperature sensor disposed upstream of the catalyst and a downstream temperature sensor disposed downstream of the catalyst, and the upstream temperature sensor and the downstream temperature sensor 4. The fuel cell system according to claim 3, wherein heat generation on the catalyst is detected based on a temperature difference between the measured temperatures.

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