JP2005268054A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system equipped with an abnormal state suppressing function and making vehicle loading possible. <P>SOLUTION: The fuel cell system in which fluid H2 is supplied to a fuel cell 10 is equipped with a housing part 11 for housing the fuel cell 10 and an oxygen concentration reducing means Vh3, 20 reducing oxygen concentration on the inside of the housing part 11 by filling the fluid H2 in the housing part 11 when abnormality is detected in the housing part 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell system having an abnormal state suppressing function.

As an abnormal state suppression method in a fuel cell system, for example, there is a method described in Japanese Patent Application Laid-Open No. 2001-189161. According to this method, an impact detection sensor for detecting an impact such as an automobile collision accident, an abnormal signal generating means for generating an abnormal signal based on an output value of the impact detection sensor, and a raw fuel gas based on the abnormal signal And an on-off valve as a reformer introduction gas stop means for stopping the supply of the oxidant gas, an inert gas cylinder, a shut-off valve for inert gas filling provided before and after the reformer, and inert based on an abnormal signal And an on-off valve for introducing gas (Patent Document 1).
JP 2001-189161 A (paragraph number 0017)

  However, in the above conventional technique, an inert gas tank must be provided in addition to the fuel gas supply device, and the system has to be enlarged. In particular, in a fuel cell system mounted on a mobile body, it is not preferable that the weight and volume increase due to functions that are rarely used, and the above-described conventional technology is not suitable as a vehicle-mounted safety device.

  Accordingly, an object of the present invention is to provide a vehicle-mounted fuel cell system having an abnormal state suppressing function.

  In order to solve the above-described problems, the present invention provides a fuel cell system in which a fluid is supplied to a fuel cell. And oxygen concentration reducing means for reducing the oxygen concentration inside the accommodating portion by filling the fluid inside the portion.

  According to the above configuration, when an abnormality is detected, the container is filled with fluid, the oxygen concentration is lowered, and an oxygen deficient state occurs, thereby suppressing the abnormal state (oxidation reaction state). At this time, the medium that creates the oxygen deficient state is a fluid for the fuel cell that is used in normal operation, and therefore, it is not necessary to provide special equipment for suppressing the abnormal state. For this reason, the system can be made compact and lightweight, and an abnormal state suppression facility suitable for in-vehicle use can be provided.

  Here, for example, “fluid” is fuel gas. By filling the fuel gas, the oxygen concentration can be reduced, and since the fuel gas is mounted in a large amount for the fuel cell system, it has an abnormal state suppression function without providing special equipment. Can do.

  For example, “fluid” is cooling water. Filling with cooling water can also reduce the oxygen concentration, and since cooling water is mounted in large quantities for cooling the fuel cell, it can have an abnormal state suppression function without providing special equipment. .

  Here, it is preferable to provide a means for reducing the temperature of the cooling water, and to reduce the temperature of the cooling water when the cooling water is filled in the accommodating portion. According to this configuration, the cooling water reduces the oxygen concentration, and at the same time, the cooling water takes away the heat generated in the abnormal state, so that the abnormal state suppression activity is performed safely and early.

  The oxygen concentration reducing means may be configured to close the opening / closing member when an abnormality is detected. Since the accommodating portion has a communication portion, the fuel gas can be discharged during normal operation, and when an abnormality is detected, the housing portion can be closed to easily create a sealed state.

  Further, the present invention provides a fuel cell system including a fuel cell, a housing portion that seals the fuel cell, a driving unit that discharges gas in the housing portion, and a driving unit that drives the driving unit when an abnormality is detected in the housing unit. And oxygen concentration reducing means for reducing the oxygen concentration in the accommodating part by discharging the gas in the accommodating part.

  According to the above configuration, when an abnormality is detected, the gas is discharged by the driving means, so that the oxygen concentration is reduced and the abnormal state can be suppressed.

  In the present invention, the driving means is preferably a compressor that supplies an oxidizing gas to the cathode electrode of the fuel cell. The compressor used during normal operation can also be used to discharge the oxidizing gas.

  Further, it is preferable that the oxygen concentration reducing means is configured to stop the supply of the fuel gas and the oxidizing gas when there is an abnormality. This is because the abnormal state is calmed down if these gases are stopped.

  As described above, according to the present invention, since the medium that creates an oxygen deficiency state when an abnormality is detected is a fluid for a fuel cell that is used in normal operation, special equipment for suppressing the abnormal state is provided. Since this is not necessary, it is possible to provide a fuel cell system that is compact and can be mounted on a vehicle.

  Next, preferred embodiments for carrying out the present invention will be described with reference to the drawings. The following embodiments are merely examples of the present invention, and the present invention is applicable without being limited thereto.

(Embodiment 1)
In the first embodiment, a fuel cell system having the abnormal state suppressing function of the present invention is applied to a moving body such as an electric vehicle, and particularly, a fuel gas is filled as a fluid. FIG. 1 shows the piping and valve structure around the fuel cell stack in the fuel cell system. As shown in FIG. 1, the fuel cell system includes a system for supplying hydrogen gas (H2) as a fuel gas to the fuel cell stack 10, a system for supplying air (Air) as an oxygen source, and A system for supplying cooling water to cool the fuel cell stack 10 is provided.

  The fuel cell stack 10 has a stack structure in which a plurality of cells composed of a separator having a flow path of hydrogen gas, air, and cooling water and a MEA (Membrane Electrode Assembly) sandwiched between a pair of separators are stacked. . The MEA has a structure in which a polymer electrolyte membrane is sandwiched between two electrodes, a fuel electrode and an air electrode. The fuel electrode has a fuel electrode catalyst layer provided in the form of a porous support layer, and the air electrode has an air electrode catalyst layer provided on the porous support layer.

  The fuel gas is supplied to the fuel cell stack 10 through a pipe 1 from a hydrogen tank or the like, which is a hydrogen gas supply source (not shown), and is discharged as hydrogen off-gas through the pipe 2. The pipe 1 is provided with a hydrogen inlet shut-off valve Vh1, and the pipe 2 is provided with a hydrogen outlet shut-off valve Vh2. When the operation of the fuel cell stack 10 is stopped in response to a control signal from the control unit 20, the fuel gas flows. It is possible to shut off. In particular, a branch pipe 7 communicates with the upstream side of the hydrogen inlet shutoff valve Vh 1 of the pipe 1, and a hydrogen filling control valve Vh 3 that allows the branch pipe 7 to flow is provided.

  The air is taken in from an air cleaner (not shown), pressurized by the compressor 12, supplied to the fuel cell stack 10 through the pipe 3, and discharged as air off-gas through the pipe 4. The pipe 3 is provided with an air inlet shut-off valve Va1, and the pipe 4 is provided with an air outlet shut-off valve Va4. When the operation of the fuel cell stack 10 is stopped according to a control signal from the control unit 20, the air flow is stopped. It is possible to block.

  The cooling water is circulated by a cooling pump or the like (not shown), supplied to the fuel cell stack 10 via the pipe 5 to cool the inside, discharged through the pipe 6 and recirculated.

  The fuel cell stack 10 is configured to be sealable by a casing 11. The casing 11 is chemically resistant to the fuel gas and the cooling water, and has a mechanical strength that can withstand a certain level of high pressure when the fluid such as the fuel gas and the cooling water is filled by the abnormal state suppressing process of the present invention. Prepare. The inside of the casing 11 is preferably kept low in oxygen concentration from the viewpoint of fire prevention. For example, it is preferable to keep the inside of the casing 11 at a lower pressure than the outside because the fuel gas can be filled quickly when the fuel gas is filled in the present invention. Moreover, it is preferable to fill with an inert gas because a fire hardly occurs.

  The casing 11 is provided with a temperature sensor St that can detect the internal temperature and a pressure sensor Sp that can detect the pressure, and each of them is output as a detection signal to the control unit 20.

  The shutoff valves Vh <b> 1 to Vh <b> 3, Va <b> 1, Va <b> 2 do not necessarily need to be arranged inside the casing 11, but the outlet of the branch pipe 7 needs to be provided so that at least the inside of the casing 11 can be filled with fuel gas. There is.

  The control unit 20 is a known computer system, and a CPU (Central Processing Unit) (not shown) sequentially executes a software program for executing the abnormal state suppression method of the present invention stored in a ROM (not shown). It is possible to cause the system to implement the abnormal state suppressing method of the present invention.

  Next, the abnormal state suppressing method according to the first embodiment will be described with reference to the flowchart of FIG. The flowchart is periodically executed by the control unit 20 during operation of the fuel cell system.

  In the above configuration, during normal operation, the hydrogen inlet cutoff valve Vh1 and the outlet cutoff valve Vh2 are opened to allow fuel gas to flow, and the air inlet cutoff valve Va1 and the outlet cutoff valve Va2 are opened to allow air to flow. In the single cell in the fuel cell stack 10, an electrochemical reaction occurs and electricity is generated. Since the hydrogen filling cutoff valve Vh3 is closed during normal operation, only the gas initially sealed is present in the casing 11.

  The control unit 20 refers to the detection signal from the temperature sensor St (S1) and checks whether the internal temperature of the casing 11 shows an abnormal value (S2). If no abnormality is detected (S2: NO), the abnormal state suppression process is unnecessary, but if it is determined that an abnormal situation such as the internal temperature of the casing 11 exceeding a predetermined value (S2: YES), The control unit 20 proceeds to the abnormal state suppression process of the present invention. Although the abnormality is detected here by measuring the temperature, the abnormality may be detected by a detection signal or a pressure value of the flame detector. Furthermore, the detection signal from the G sensor or the airbag sensor of the moving body may be input, and the process may be shifted to the abnormal state suppression process when it is determined that the moving body has collided.

  In the abnormal state suppression process, first, the control unit 20 closes the hydrogen inlet cutoff valve Vh1 and the outlet cutoff valve Vh2, and closes the air inlet cutoff valve Va1 and the outlet cutoff valve Va2, so that the fuel gas and air to the fuel cell stack 10 are closed. Supply / discharge is stopped (S3).

  Next, the control unit 20 opens the hydrogen filling cutoff valve Vh3 and fills the casing 11 with fuel gas via the branch pipe 7 (S4). By this control, the fuel gas is filled into the casing 11 from the branch pipe 7, and the relative oxygen concentration is lowered.

  FIG. 3 shows a relationship diagram between the hydrogen gas concentration and the abnormal state property. A curve f indicates the concentration of hydrogen gas filled in the casing 11. It shows that the battery is almost filled after time Tf has elapsed from the start of filling. The combustibility of hydrogen gas is closely related not only to the hydrogen gas concentration but also to the oxygen concentration. In the range A3 in FIG. 3, the concentration of hydrogen gas is sufficiently small (for example, less than 4%). In such a case, the hydrogen gas itself is too small to burn. On the contrary, even if the concentration of hydrogen gas is too high, the relative oxygen gas concentration is low, so that combustion is difficult. For example, in FIG. 3, when the hydrogen gas concentration enters the non-abnormal state range A1 exceeding about 75%, combustion becomes difficult. Between these is the abnormal state range A2. In the present embodiment, the inside of the casing 11 is brought into the non-abnormal range A1 by rapidly filling the fuel gas.

  That is, in step S4, the fuel gas is filled into the casing 11 from the branch pipe 7, the oxygen concentration is reduced, and even if an abnormal state occurs inside, the abnormal state is stopped due to insufficient oxygen. The control unit 20 monitors the detection signal of the pressure sensor Sp, and inspects whether the fuel gas is sufficiently filled in the casing 11 (S5). If the internal pressure does not become larger than the predetermined threshold value Pth (S5: NO), the fuel gas is continuously charged. If the internal pressure becomes larger than the threshold value Pth (S5: YES), A control signal for closing the hydrogen filling shut-off valve Vh3 is output to end the fuel gas filling (S6). In addition to detecting the completion of hydrogen filling with pressure, hydrogen filling may be stopped after confirming that the fire has been extinguished by temperature detection by temperature sensor St or the like, or hydrogen filling may be stopped based on other criteria. Good.

  As described above, according to the first embodiment, by filling the hydrogen gas as the fuel gas, the oxygen concentration in the casing 11 is reduced and the abnormal state is suppressed, so that the existing hydrogen gas supply equipment is used as it is. Therefore, an abnormal state suppression process can be performed, and a large-scale system such as a tank for supplying an inert gas is unnecessary.

  In particular, according to the first embodiment, since high-pressure fuel gas can be filled, the oxygen concentration around the fuel cell stack can be rapidly reduced, and high-speed abnormal state suppression is possible.

(Embodiment 2)
In the first embodiment, the fuel gas is filled as a fluid to reduce the oxygen concentration, but in the second embodiment, cooling water is filled as a fluid.

  FIG. 4 shows a piping structure around the fuel cell stack 10 according to the second embodiment. In the second embodiment, the hydrogen filling cutoff valve Vh3 and the branch pipe 7 for filling the inside of the casing 11 with hydrogen gas are not present. Instead, a branch pipe 8 is provided in the pipe 5 for supplying cooling water, and a cooling water filling cutoff valve Vw is provided. The cooling water filling cutoff valve Vw and the branch pipe 8 itself do not necessarily exist inside the casing 11, but at least the outlet of the branch pipe 8 needs to be arranged so that the cooling water can be filled inside the casing 11.

  The cooling water supply system includes a cooling water pump 13 for forcibly circulating the cooling water discharged from the pipe 6 and a heat exchanger 14 for removing heat from the cooling water flowing in the pipe 5. The heat exchanger 14 is further connected to a cooling device 15 so that the refrigerant circulates in the secondary circulation path and cools the cooling water by the heat exchanger 14. The configurations of the heat exchanger 14 and the cooling device 15 are not limited, but, for example, a system that cools by removing condensed heat with a condenser, or a system that cools with a radiator and a fan is applicable.

  As in the first embodiment, the inside of the casing 11 is preferably kept low in oxygen concentration from the viewpoint of fire prevention. For example, it is preferable to keep the inside of the casing 11 in a low pressure state as compared with the outside because the cooling water can be filled quickly when the cooling water is filled in the present invention. In addition to the temperature sensor St and the pressure sensor Sp, the casing 11 is provided with a water level meter Sh capable of detecting the water level, and outputs a detection signal to the control unit 20. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  In the above configuration, the cooling water discharged by the pipe 6 is forcedly circulated by the cooling pump 13, cooled by the heat exchanger 14, and then supplied to the fuel cell stack 10 by the pipe 5.

  Next, the abnormal state suppressing method according to the second embodiment will be described with reference to the flowchart of FIG. The flowchart is periodically executed by the control unit 20 during operation of the fuel cell system.

  During normal operation, since the cooling water filling cutoff valve Vw is closed, only the gas initially enclosed in the casing 11 exists.

  As in the first embodiment, the control unit 20 refers to the detection signal from the temperature sensor St (S11), and if no abnormality is detected (S12: NO), the control unit 20 passes the abnormal state suppression process and determines that there is an abnormal situation. If yes (S12: YES), the process proceeds to the abnormal state suppression process of the present embodiment. As in the first embodiment, various modifications can be made to the abnormality detection method.

  In the abnormal state suppression process, first, the control unit 20 closes the hydrogen inlet cutoff valve Vh1 and the outlet cutoff valve Vh2, and closes the air inlet cutoff valve Va1 and the outlet cutoff valve Va2, so that the fuel gas and air to the fuel cell stack 10 are closed. Supply / discharge is stopped (S13). Next, the controller 20 forcibly drives the cooling pump (S14) to increase the circulation amount of the cooling water. At the same time, the control unit 20 drives the heat exchanger 14 (S15) to maximize the cooling amount of the cooling water. For example, if the heat exchanger 14 or the cooling device 15 has a secondary circulation path, the circulation amount of the secondary circulation path is increased to operate the condenser to its full capacity. If the heat exchanger is a radiator, maximize the fan cooling speed to maximize air cooling performance.

  Then, the control unit 20 outputs a control signal for opening the cooling water filling cutoff valve Vw (S16). By opening the cooling water shutoff valve Vw, the cooling water begins to be filled into the casing 11 from the branch pipe 8. As the water level rises, gas components are removed from the periphery of the fuel cell stack 10 and, as a result, the oxygen concentration is greatly reduced.

  By filling the cooling water, the reduction of the oxygen concentration becomes dramatic, and the abnormal state suppression of the fuel cell stack 10 becomes more complete. Here, the control unit 20 monitors the detection signal of the water level sensor Sh, and inspects whether or not the cooling water is filled up to a certain water level in the casing 11 (S17). If the water level does not become higher than the predetermined water level Hth (NO), the cooling water will continue to be charged, but if the water level becomes higher than a certain value Hth (YES), the cooling water filling shutoff valve Vw is closed. The control signal to output is output, and cooling water discharge is terminated (S18). In addition, the point which may stop cooling water filling on the basis other than a water level is the same as that of Embodiment 1.

  As described above, according to the second embodiment, since the oxygen concentration inside the casing 11 is reduced and the abnormal state is suppressed by filling the cooling water, the abnormal state suppressing process is performed only by using the existing cooling water supply equipment as it is. This eliminates the need for a large-scale system such as a tank for supplying an inert gas.

  In particular, according to the second embodiment, since the cooling water is filled, the abnormal state can be reliably suppressed. In addition, since the cooling water is filled after the cooling capacity of the cooling water is increased, the heat can be quickly taken away from the place causing the abnormal state, and the abnormal state can be quickly suppressed.

  In addition, it is preferable to perform the fuel gas filling in the first embodiment in combination with the cooling water filling in the second embodiment. This is because the abnormal state suppression system can be made more reliable by reducing the oxygen concentration in the initial stage by filling the high-pressure fuel gas and then reliably achieving the abnormal state suppression by filling the cooling water.

(Embodiment 3)
This Embodiment 3 is related with the casing provided with the ventilation window.

  FIG. 6 shows a piping structure around the fuel cell stack 10 according to the third embodiment. The third embodiment is characterized in that the casing 11 is provided with a ventilation window 17 that is a communication portion. The casing 11 has a structure that can be sealed as in the above embodiments, but in this embodiment, a ventilation window 17 is formed. The ventilation window 17 is provided with a lid 18 that can close the ventilation window 17 almost completely. The lid 18 is opened by a motor 19 that is driven based on a control signal from the control unit 20. The gas can be discharged to the outside, or the inside can be suffocated as a closed state.

  In addition, it is preferable to make the volume of the casing 11 in the third embodiment as small as possible within a range in which the fuel cell stack 10 can be accommodated. This is because the state of suffocation can be achieved at an early stage by reducing the amount of oxygen contained therein as much as possible.

  The other fuel gas supply system, air supply system, and cooling water supply system are the same as those in the first embodiment, and a description thereof will be omitted.

  Next, the abnormal state suppressing method according to the third embodiment will be described with reference to the flowchart of FIG. The flowchart is periodically executed by the control unit 20 during operation of the fuel cell system.

  During normal operation, the lid 18 is open, and gas inside and outside the casing 11 can flow through the ventilation window 17. Since the ventilation window 17 is opened, even if a gas leak occurs in the fuel cell stack 10, it is discharged to the outside.

  As in the first embodiment, the control unit 20 refers to the detection signal from the temperature sensor St (S21), and if no abnormality is detected (S22: NO), it passes the abnormal state suppression process and determines that it is an abnormal situation. If yes (22: YES), the process proceeds to the abnormal state suppression process of the present embodiment. As in the first embodiment, various modifications can be made to the abnormality detection method.

  In the abnormal state suppression process, first, the control unit 20 closes the hydrogen inlet cutoff valve Vh1 and the outlet cutoff valve Vh2, and closes the air inlet cutoff valve Va1 and the outlet cutoff valve Va2, so that the fuel gas and air to the fuel cell stack 10 are closed. Supply / discharge is stopped (S23).

  And the control part 20 supplies a control signal to the motor 19, makes the cover part 18 close, closes the ventilation window 17, and makes the casing 11 a sealing state (S24). By setting it as such a sealed state, oxygen will be deficient in a short time from the casing 11 with a small volume, and an abnormal state will converge.

  Then, it is inspected whether or not the abnormal state suppression is completed (S25). If the abnormal state is suppressed (S25: YES), the control unit 20 outputs a control signal for causing the motor 19 to open the lid 18 (S26). If the abnormal state is not suppressed (S25: NO), the sealed state is continuously maintained. For confirmation of the presence or absence of abnormal state suppression, the temperature and pressure inside the casing 11 can be used as in the first embodiment.

  In addition, since abnormal state suppression by sealing takes time, once the cover part 18 is closed, it may be left as it is, and then the closed state may be maintained until the user confirms safety and resets the system.

  As described above, according to the third embodiment, since the oxygen concentration in the casing 11 is reduced and the abnormal state suppression is promoted by positively creating a sealed state, the abnormal state suppression process can be performed only by using the existing equipment as it is. This can be done and does not require a large system such as a tank for supplying inert gas.

  In particular, according to the third embodiment, the abnormal state can be suppressed only by a relatively simple process of closing the lid.

  In addition, it is preferable to perform the fuel gas filling in the first embodiment and the cooling water filling in the second embodiment in combination with the sealing process of the third embodiment. After shutting off the oxygen supply by sealing, the oxygen concentration is further reduced by filling with high-pressure fuel gas, and then the abnormal state suppression is reliably achieved by cooling water filling, thereby making the abnormal state suppression system more reliable It is because it can be made.

(Embodiment 4)
The fourth embodiment relates to a system that actively removes oxygen.

  FIG. 8 shows a piping structure around the fuel cell stack 10 according to the fourth embodiment. The fourth embodiment is characterized in that the casing 11 is provided with a suction pipe 91. The suction pipe 91 is connected upstream of the compressor 12 in the air pipe 3. The suction pipe 91 is provided with a shutoff valve Va4. Further, a branch pipe 92 is provided downstream of the air pipe 3 and outside the casing 11, and a shut-off valve Va <b> 3 for shutting off air flow through the branch pipe 92 is provided. A main valve Va5 is further provided upstream of the junction of the branch pipe 91 with the pipe 3. The shut-off valves Va3, Va4 and Va5 are configured to open and close based on a control signal from the control unit 20.

  In addition, it is preferable that the casing 11 in the fourth embodiment has a volume as small as possible within a range in which the fuel cell stack 10 can be accommodated. This is because the state of suffocation can be achieved at an early stage by reducing the amount of oxygen contained therein as much as possible. The other fuel gas supply system, air supply system, and cooling water supply system are the same as those in the first embodiment, and a description thereof will be omitted.

  Next, the abnormal state suppressing method according to the fourth embodiment will be described with reference to the flowchart of FIG. The flowchart is periodically executed by the control unit 20 during operation of the fuel cell system.

  During normal operation, the hydrogen inlet shutoff valve Vh1 and the outlet shutoff valve Vh2 are opened to allow fuel gas to flow, and the air inlet shutoff valve Va1 and the outlet shutoff valve Va2 are opened to allow air to flow, whereby the fuel cell stack 10 In the single cell inside, an electrochemical reaction occurs, electricity is generated, and electricity is generated. Further, the shut-off valves Va3 and Va4 are shut off during normal operation.

  As in the first embodiment, the control unit 20 refers to the detection signal from the temperature sensor St (S31), and if no abnormality is detected (S32: NO), it passes the abnormal state suppression process and determines that it is an abnormal situation. If yes (S32: YES), the process proceeds to the abnormal state suppression process of the present embodiment. As in the first embodiment, various modifications can be made to the abnormality detection method.

  In the abnormal state suppression process, the control unit 20 closes the hydrogen inlet shut-off valve Vh1 and the outlet shut-off valve Vh2, and closes the air inlet shut-off valve Va1 and the outlet shut-off valve Va2, so that the fuel gas and air to the fuel cell stack 10 are blocked. Supply / discharge is stopped (S33). Further, the main valve Va5 is also closed.

  Next, the control unit 20 outputs a control signal for opening the shut-off valves Va4 and Va3 (S34), and then outputs a drive signal for rotating the compressor 12 at a high speed (S35). By this processing, the gas inside the casing 11 is sucked by the negative pressure on the inlet side of the compressor 12 and discharged from the branch pipe 92 to the outside. For this reason, the casing 11 becomes deficient in a short time and the abnormal state converges.

  If the abnormal state is suppressed by the above suction processing (S36: YES), the control unit 20 stops the compressor 12 (S37), but if the abnormal state suppression is not confirmed (S36: NO), the compressor continues to be driven. (S35). Note that the temperature and pressure inside the casing 11 can be used in the same manner as in the first embodiment for checking whether or not the abnormal state is suppressed.

  As described above, according to the fourth embodiment, the gas inside the casing is sucked to actively suck the oxygen as the combustion-supporting gas, thereby reducing the oxygen concentration inside the casing 11 and promoting the abnormal state suppression. By using existing equipment as it is, abnormal state suppression processing can be performed, and a large-scale system such as a tank for supplying an inert gas is unnecessary. In particular, according to the fourth embodiment, the abnormal state can be suppressed only by a relatively simple process of switching between opening and closing of the valve.

  In addition, it is preferable to perform the filling of the fuel gas in the first embodiment, the filling of the cooling water in the second embodiment, and the closing of the lid in the third embodiment in combination with the suction process of the fourth embodiment. If a ventilation window is provided, the ventilation window is closed and then the internal gas is sucked to reduce the oxygen concentration, and the oxygen concentration is further reduced by filling with high-pressure fuel gas. This is because the abnormal state suppression system can be made more reliable by achieving the state suppression.

(Other embodiments)
The present invention is not limited to the above embodiments and can be used with various modifications.

  For example, in the above embodiment, the casing is filled with hydrogen gas and cooling water as fluids, but other fluids may be poured. For example, if air is allowed to pass through the oxygen separation structure and supplied into the casing, the combustion-supporting oxygen is removed, and nitrogen, which is the main component of air, is filled inside the casing, thus reducing the oxygen concentration. be able to.

  As another embodiment, the lid member of the fourth embodiment may be opened and closed in a sliding manner. Further, as the communication portion, a communication pipe that communicates the casing 17 and the outside thereof may be provided instead of the window, and an open / close electromagnetic valve may be provided on the communication pipe.

  When the fuel cell system is a system having a reformer, the present invention may be applied to a casing including the reformer. It is also possible to accommodate the reformer and the fuel cell stack in separate casings and apply the structure of the present invention as described in the above embodiment to each casing.

1 is a configuration diagram of a fuel cell stack according to Embodiment 1. FIG. 3 is a flowchart for explaining an oxygen reduction method according to the first embodiment. The figure which shows the relationship between hydrogen gas concentration and abnormal condition property. FIG. 3 is a configuration diagram of a fuel cell stack according to Embodiment 2. 9 is a flowchart for explaining an oxygen reduction method according to the second embodiment. FIG. 5 is a configuration diagram of a fuel cell stack according to Embodiment 3. 10 is a flowchart for explaining an oxygen reduction method according to the third embodiment. FIG. 6 is a configuration diagram of a fuel cell stack according to Embodiment 4. 10 is a flowchart for explaining an oxygen reduction method according to the fourth embodiment.

Explanation of symbols

  Sp ... Pressure sensor, St ... Temperature sensor, Sh ... Water level sensor, Vh1-Vh3 ... Hydrogen gas shut-off valve, Va1-Va5 ... Air shut-off valve, 10 ... Fuel cell stack, 11 ... Housing, 12 ... Compressor, 13 ... Hydrogen Pump, 14 ... Heat exchanger, 15 ... Cooling device, 17 ... Ventilation window, 18 ... Lid, 19 ... Motor, 20 ... Controller

Claims (8)

In a fuel cell system in which fluid is supplied to the fuel cell,
An accommodating portion for enclosing the fuel cell in a sealable manner;
A fuel cell system comprising: oxygen concentration reducing means for reducing the oxygen concentration inside the housing portion by filling the fluid inside the housing portion when an abnormality is detected in the housing portion.   The fuel cell system according to claim 1, wherein the fluid is a fuel gas.   The fuel cell system according to claim 1, wherein the fluid is cooling water. Means for reducing the temperature of the cooling water;
The fuel cell system according to claim 3, wherein a temperature of the cooling water is reduced when the cooling water is filled in the housing portion. A communication portion for communicating the housing portion with the outside thereof;
An opening and closing member for opening and closing the communication portion,
The fuel cell system according to claim 1, wherein the oxygen concentration reducing unit closes the opening / closing member when an abnormality is detected. In a fuel cell system comprising a fuel cell,
An accommodating portion for enclosing the fuel cell in a sealable manner;
Driving means for discharging the gas in the housing part;
An oxygen concentration reducing unit that drives the driving unit when the abnormality in the housing unit is detected and discharges the gas in the housing unit to reduce the oxygen concentration in the housing unit. Battery system.   The fuel cell system according to claim 6, wherein the driving means is a compressor that supplies an oxidizing gas to a cathode electrode of the fuel cell. The fuel cell system according to any one of claims 1 to 7, wherein the oxygen concentration reduction unit stops supply of fuel gas and oxidizing gas when the abnormality occurs.

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