JP2014232709A - Fuel battery device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery device that has improved long reliability by efficiently performing an operation stopping process.SOLUTION: In a fuel battery device, when a control device 7 stops the operation of a fuel battery module 4, it exerts control such that the supply/stop of a fluid flowing in a raw fuel supply line, an oxygen-containing gas supply line, a water supply line and an inactive gas supply line are switched. Thereby, while oxidation of a fuel battery cell is hindered, an operation stopping process is efficiently performed with less inactive gas.

Description

  The present invention relates to a fuel cell device.

  In recent years, as a next-generation energy, a cell stack in which a plurality of fuel cells that can obtain electric power using a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air) are arranged is known. Various fuel cell modules in which a cell stack is stored in a storage container and fuel cell devices in which a fuel cell module is stored in an outer case have been proposed.

  Many operation methods of such a fuel cell device have been proposed, and various operation stop methods are also available for the operation stop such as detecting the abnormality of the fuel cell in addition to the normal operation stop of the fuel cell. Is being considered.

  As an example of such an operation stop method, for example, after stopping the supply of fuel gas or oxidizing gas in a high temperature state, the power generation operation is stopped in a high temperature state by purging the fuel cell with an inert gas. The driving | running method provided with a driving | operation stop process is illustrated (for example, refer patent document 1).

JP 2006-100153 A

  By the way, when such a fuel cell device is shut down, it is generally considered to stop the operation by lowering the temperature using air. In this case, depending on the stop condition, the fuel cell is oxidized. There was a problem that could lead to damage.

  Therefore, it has been proposed to purge the inside of the fuel cell with an inert gas in a high temperature state as in Patent Document 1, but in this case, there is a possibility that a large amount of the inert gas may be required, and the fuel cell device There was also a problem that the size of the system increased.

  Therefore, according to the present invention, in the operation stop processing of the fuel cell device, the operation stop processing can be efficiently performed with a small amount of inert gas while suppressing the oxidation of the fuel cell, and the increase in size can be suppressed. An object is to provide an apparatus.

The fuel cell device of the present invention includes a fuel cell module in which a fuel cell that generates power with fuel gas and an oxygen-containing gas is stored in a storage container, and a temperature measuring means for measuring the temperature in the fuel cell module. A reformer for generating fuel gas to be supplied to the fuel cell by steam reforming, a raw fuel supply line for supplying raw fuel to the reformer, and supplying water to the reformer A water supply line, an oxygen-containing gas supply line for supplying the oxygen-containing gas to the fuel cell, an inert gas supply line for supplying an inert gas into the fuel cell module, and a fluid flowing through each supply line A control device for controlling the supply and stop of the fuel cell, and when the operation of the fuel cell module is stopped, the control device is configured to control the raw fuel supply line, the acid, and Containing gas supply line, and performing control to change the supply and stop of the fluid flowing through the water supply line and the inert gas supply line.

  In the fuel cell device of the present invention, when the control device stops the operation of the fuel cell module, the raw fuel supply line, the oxygen-containing gas supply line, the water supply line, and the inert gas are selected according to the operation stop condition. Since the control for changing the supply and stop of the fluid flowing through the supply line is performed, the supply and stop of the fluid flowing through each supply line is controlled according to the operation stop condition, thereby suppressing the oxidation of the fuel cell. Therefore, the operation stop process can be efficiently performed with a small amount of inert gas, and the increase in size can be suppressed.

It is a block diagram which shows an example of a structure of a fuel cell system provided with the fuel cell apparatus of this embodiment. It is an external appearance perspective view which shows an example of the fuel cell module which comprises the fuel cell system shown in FIG. FIG. 3 is a cross-sectional view of the fuel cell module shown in FIG. 2. It is a flowchart which shows an example of the stop control of the driving | operation of the fuel cell module of this embodiment. It is a flowchart which shows the part shown by A among the flowcharts shown in FIG. It is a flowchart which shows the part shown by B among the flowcharts shown in FIG. It is a flowchart which shows the part shown by B among the flowcharts shown in FIG. It is a disassembled perspective view which shows roughly an example of the fuel cell apparatus of this embodiment.

  FIG. 1 is a configuration diagram illustrating an example of a configuration of a fuel cell system including the fuel cell device of the present embodiment. The fuel cell system shown in FIG. 1 includes a power generation unit that is an example of the fuel cell device of the present embodiment, a hot water storage unit that stores hot water after heat exchange, and a circulation pipe that circulates water between these units. It is composed of In the following drawings, the same components are described using the same reference numerals.

  The power generation unit shown in FIG. 1 will be described later with a cell stack 5 formed by combining a plurality of solid oxide fuel cells having a fuel side electrode layer, a solid electrolyte layer, and an air side electrode layer, and raw fuel such as city gas. A raw fuel supply line having a raw fuel supply pump 1 for supplying to a reformer 3 and an oxygen-containing gas having an oxygen-containing gas supply pump (blower) 2 for supplying oxygen-containing gas to fuel cells constituting the cell stack 5 A gas supply line and a reformer 3 for steam reforming the raw fuel with the raw fuel and steam are provided. The raw fuel supply line 1 is provided with a raw fuel flow meter 41 for measuring the amount of raw fuel supplied from the raw fuel supply pump 1, and the oxygen-containing gas supply line is provided with an oxygen-containing gas supply pump 2. An oxygen-containing gas flow meter 42 for measuring the amount of oxygen-containing gas supplied is provided.

  In the power generation unit shown in FIG. 1, a fuel cell module 4 (hereinafter sometimes referred to as a module) is configured by storing the cell stack 5 and the reformer 3 in a storage container. It is shown surrounded by a two-dot chain line. Although not shown in FIG. 1, the exhaust gas line that exhausts exhaust gas that has not been used for power generation discharged from the cell stack 5 can be provided with a purification device for purifying the exhaust gas, and a module. An ignition device for combusting fuel gas that has not been used for power generation can be provided in 4.

  Further, in the power generation unit shown in FIG. 1, a circulation pipe 15 that circulates water to a heat exchanger 8 that performs heat exchange between exhaust gas (exhaust heat) generated by power generation of fuel cells constituting the cell stack 5 and water. A water treatment device 9 for treating the condensed water generated in the heat exchanger 8 with pure water, and a water tank 11 for storing water (pure water) treated with the water treatment device 9 are provided. The water tank 11 and the heat exchanger 8 are connected by a condensed water supply pipe 10. In the present embodiment, the space between the module 4 and the heat exchanger 8 is called an exhaust gas line. Moreover, as the water treatment apparatus 9, it is preferable to use an ion exchange resin apparatus provided with an ion exchange resin.

  The water stored in the water tank 11 is supplied to the reformer 3 by a water pump 12 provided in a water supply pipe 13 that connects the water tank 11 and the reformer 3. The water supply pipe 13 is provided with a water flow meter 43 for measuring the flow rate of the water supplied from the water pump 12. In this embodiment, the water pump 12 and the reformer 3 are connected to each other. The space is called the water supply line.

  Further, the power generation unit shown in FIG. 1 converts the DC power generated by the module 4 into AC power, and adjusts the supply amount of the converted electricity to the external load (power conditioner). 6. Control device 7 for controlling the operation of various devices described later in addition to the outlet water temperature sensor 14 for measuring the water temperature of the water (circulated water flow) provided at the outlet of the heat exchanger 8 and flowing through the outlet of the heat exchanger 8 The power generation unit is configured together with a circulation pump 17 that circulates water in the circulation pipe 15. The control device 7 includes a microcomputer and includes an input / output interface, a CPU, a RAM, and a ROM. The CPU performs the operation of the fuel cell device, the RAM temporarily stores variables necessary for executing the program, and the ROM stores the program.

  And each apparatus which comprises these electric power generation units can be set as a fuel cell apparatus with easy installation, carrying, etc. by accommodating in an exterior case. The hot water storage unit includes a hot water storage tank 16 for storing hot water after heat exchange. The circulation pump 17 can also be provided on the hot water storage unit side.

  Here, an operation method of the fuel cell system shown in FIG. 1 will be described.

  In generating fuel gas necessary for power generation in the cell stack 5, the control device 7 operates the raw fuel supply pump 1 and the water pump 12. As a result, raw fuel (natural gas, kerosene, etc.) and water are supplied to the reformer 3, and by performing steam reforming in the reformer 3, a fuel gas containing hydrogen is generated and the fuel cell. Supplied to the fuel electrode layer side.

  On the other hand, the control device 7 operates the oxygen-containing gas supply pump 2 to supply oxygen-containing gas (air) to the oxygen electrode layer side of the fuel cell.

  The control device 7 operates an ignition device (not shown) in the module 4 to burn fuel gas that has not been used for power generation of the cell stack 5. Thereby, the temperature in the module (the temperature of the cell stack 5 and the reformer 3) rises, and efficient power generation can be performed.

The exhaust gas generated with the power generation of the cell stack 5 is purified by the purification device, then supplied to the heat exchanger 8 and heat-exchanged with water flowing through the circulation pipe 15. Hot water generated by heat exchange in the heat exchanger 8 flows through the circulation pipe 15 and is stored in the hot water storage tank 16. On the other hand, water contained in the exhaust gas discharged from the cell stack 5 by heat exchange in the heat exchanger 8 becomes condensed water and is supplied to the water treatment device 9 through the condensed water supply pipe 10. The condensed water is made pure water by the water treatment device 9 and supplied to the water tank 11. The water stored in the water tank 11 is supplied to the reformer 3 by the water pump 12 via the water supply pipe 13. Thus, water self-sustained operation can be performed by effectively using condensed water.

  In the above-described example, the fuel cell device configured to supply only the condensed water generated by the heat exchanger 8 to the reformer 3 has been described. Can also be used. In this case, as a water treatment device for treating impurities contained in tap water, for example, an activated carbon filter, a reverse osmosis membrane device, an ion exchange resin device, etc. are connected in this order to efficiently purify pure water. be able to. In addition, also when using tap water, each apparatus is connected so that the pure water produced | generated with the water treatment apparatus may be stored in the water tank 11. FIG.

  Next, an example of the module 4 shown in FIG. 1 will be described. 2 and 3 show an example of the module 4 constituting the fuel cell device of the present embodiment, FIG. 2 is an external perspective view showing the module 4, and FIG. 3 is a sectional view of the module 4 shown in FIG. is there.

  In the module 4 shown in FIG. 2, columnar fuel cells 19 having gas flow paths (not shown) through which fuel gas flows are arranged in a row inside the storage container 18. The adjacent fuel cells 19 are electrically connected in series via current collecting members (not shown), and the lower end of the fuel cells 19 is connected to an insulating bonding material (not shown) such as a glass sealant. The cell stack device 21 having two cell stacks 5 fixed to the manifold 20 is housed. At both ends of the cell stack 5, conductive members having electrical lead portions for collecting the electricity generated by the power generation of the cell stack 5 (fuel cell 19) and drawing it outside are disposed ( Not shown). 2 shows the case where the cell stack device 21 includes two cell stacks 5, the number can be changed as appropriate. For example, even if only one cell stack 5 is provided. Good. In addition, the storage container 18 is provided with a thermocouple 27 which is a temperature measuring means for measuring the temperature of the module 4.

  In FIG. 2, the fuel battery cell 19 is a hollow flat plate type having a gas flow path through which fuel gas flows in the longitudinal direction. A fuel electrode layer, a solid electrolyte is formed on the surface of a support having the gas flow path. A solid oxide fuel cell 19 in which a layer and an oxygen electrode layer are sequentially laminated is illustrated. In addition, in the fuel battery cell 19, it is also possible to have a shape having a gas flow path through which the oxygen-containing gas flows in the longitudinal direction. In this case, the oxygen electrode layer, the solid electrolyte layer, and the fuel electrode layer are sequentially arranged from the inside. The configuration of the module 4 may be changed as appropriate. Furthermore, the fuel cell is not limited to the hollow plate type, and may be a plate type or a cylindrical type, for example, and it is preferable to change the shape of the storage container 18 as appropriate.

  Further, in the module 4 shown in FIG. 2, in order to obtain the fuel gas used in the power generation of the fuel battery cell 19, the raw fuel such as city gas supplied through the raw fuel supply pipe 25 is reformed to produce the fuel gas. A reformer 3 for generating gas is disposed above the cell stack 5. In addition, the reformer 3 can have a structure capable of performing steam reforming, which is an efficient reforming reaction, and a reforming unit 23 for vaporizing water and reforming raw fuel into fuel gas. And a reforming section 22 in which a reforming catalyst (not shown) is disposed.

  The fuel gas (hydrogen-containing gas) generated by the reformer 3 is supplied to the manifold 20 via the fuel gas circulation pipe 24 and is supplied from the manifold 20 to the gas flow path provided inside the fuel battery cell 19. Supplied. The configuration of the cell stack device 21 can be changed as appropriate depending on the type and shape of the fuel battery cell 19. For example, the reformer 3 can be included in the cell stack device 21.

FIG. 2 shows a state in which a part (front and rear surfaces) of the storage container 18 is removed and the cell stack device 21 stored inside is taken out rearward. Here, in the module 4 shown in FIG. 2, the cell stack device 21 can be slid and stored in the storage container 18.

  The reaction container 18 is disposed between the cell stacks 5 juxtaposed to the manifold 20 and is reacted inside the storage container 18 so that the oxygen-containing gas flows laterally from the lower end portion toward the upper end portion of the fuel cell 19. A gas introduction member 26 is disposed.

  As shown in FIG. 3, the storage container 18 constituting the module 4 has a double structure having an inner wall 29 and an outer wall 30, and an outer frame of the storage container 18 is formed by the outer wall 30, and a cell stack is formed by the inner wall 29. A power generation chamber 31 that houses the device 21 is formed. Further, in the storage container 18, a reaction gas flow path 36 is supplied between the inner wall 29 and the outer wall 30 from the bottom of the module 4 and through which oxygen-containing gas introduced into the fuel cell 19 flows. The oxygen-containing gas is supplied from an oxygen-containing gas supply port (not shown) provided at the bottom of the module 4 and flows through the reaction gas channel 36.

  Here, the storage container 18 is provided with an oxygen-containing gas inlet (not shown) for allowing oxygen-containing gas to flow into the upper end side from the upper portion of the storage container 18 and a flange portion 39, and a fuel at the lower end portion. A reaction gas introduction member 26 provided with a reaction gas outlet 32 for introducing an oxygen-containing gas at the lower end of the battery cell 19 is inserted through the inner wall 29 and fixed. A heat insulating member 33 is disposed between the flange portion 39 and the inner wall 29.

  In FIG. 3, the reaction gas introduction member 26 is disposed so as to be positioned between two cell stacks 5 juxtaposed inside the storage container 18, but is appropriately disposed depending on the number of cell stacks 5. be able to. For example, when only one cell stack 5 is stored in the storage container 18, two reaction gas introduction members 26 can be provided so that the cell stack 5 is sandwiched from both side surfaces.

  Further, in the power generation chamber 31, the temperature in the module 4 is maintained at a high temperature so that the heat in the module 4 is extremely dissipated and the temperature of the fuel cell 19 (cell stack 5) is lowered and the power generation amount is not reduced. A heat insulating member 33 is appropriately provided.

  The heat insulating member 33 is preferably disposed in the vicinity of the cell stack 5. In particular, the heat insulating member 33 is disposed on the side surface side of the cell stack 5 along the arrangement direction of the fuel cells 19, and the fuel cell unit on the side surface of the cell stack 5. It is preferable to arrange the heat insulating member 33 having a width equal to or greater than the width along the 19 arrangement directions. In addition, it is preferable to arrange the heat insulating members 33 on both side surfaces of the cell stack 5. Thereby, it can suppress effectively that the temperature of the cell stack 5 falls. Furthermore, the oxygen-containing gas introduced from the reaction gas introduction member 26 can be suppressed from being discharged from the side surface side of the cell stack 5, and the flow of the oxygen-containing gas between the fuel cells 19 constituting the cell stack 5 can be reduced. Can be promoted. In the heat insulating members 33 arranged on both side surfaces of the cell stack 5, the flow of the oxygen-containing gas supplied to the fuel cell 19 is adjusted, and the longitudinal direction of the cell stack 5 and the stacking direction of the fuel cell 19 are adjusted. An opening 34 is provided to reduce the temperature distribution at. Note that the opening 34 may be formed by combining a plurality of heat insulating members 33.

  Further, an exhaust gas inner wall 35 is provided on the inner side of the inner wall 29 along the arrangement direction of the fuel cells 19, and the exhaust gas in the power generation chamber 31 extends from above between the inner wall 29 and the exhaust gas inner wall 35. The exhaust gas flow path 37 flows downward. The exhaust gas passage 37 communicates with an exhaust hole 40 provided at the bottom of the storage container 18. A heat insulating member 33 is also provided on the exhaust gas inner wall 35 on the cell stack 5 side.

  Thereby, the exhaust gas generated by the operation of the module 4 flows through the exhaust gas passage 37 and is then exhausted from the exhaust hole 40. The exhaust hole 40 may be formed by cutting out a part of the bottom of the storage container 18 or may be formed by providing a tubular member. Further, a purification device (for example, a honeycomb-like combustion catalyst or the like) for purifying exhaust gas discharged from the module 4 can be provided in the exhaust hole 40.

  Although not shown, in the module 4, an ignition device for igniting the fuel gas that has passed through the fuel battery cell 19 is positioned between the fuel battery cell 19 and the reformer 3. It is preferably inserted from the side surface of the storage container 2. In addition, by igniting the fuel gas that has passed through the fuel cell 19 by the ignition device, the temperature in the module 4 can be increased, and the temperature of the fuel cell 19 and the reformer 3 is maintained at a high temperature. be able to.

  Below, the structure of the fuel cell 19 of this embodiment is demonstrated. The fuel cell 19 will be described using a conventionally known hollow plate type fuel cell 19.

  The fuel cell 19 includes a fuel-side electrode layer, a solid electrolyte layer, and an air-side electrode on one flat surface of a columnar conductive support substrate (hereinafter, may be abbreviated as a support substrate) having a pair of opposed flat surfaces. It consists of a columnar shape (hollow flat plate shape) formed by sequentially laminating layers. Further, an interconnector is provided on the other flat surface of the fuel cell 19, and a P-type semiconductor layer is provided on the outer surface (upper surface) of the interconnector. By connecting the current collecting member to the interconnector via the P-type semiconductor layer, the contact between the two becomes an ohmic contact, and it is possible to reduce the potential drop and effectively avoid the deterioration of the current collecting performance. The support substrate also serves as a fuel-side electrode layer, and a cell can be formed by sequentially laminating a solid electrolyte layer and an air-side electrode layer on the surface thereof.

As the fuel-side electrode layer, generally known ones can be used, and porous conductive ceramics, for example, ZrO ₂ in which rare earth elements are dissolved (referred to as stabilized zirconia, including partial stabilization). ) And Ni and / or NiO.

The solid electrolyte layer functions as an electrolyte that bridges the electrons between the fuel side electrode layer and the air side electrode layer, and at the same time has a gas barrier property to prevent leakage between the fuel gas and the oxygen-containing gas. And is formed from ZrO ₂ in which 3 to 15 mol% of rare earth elements are dissolved. In addition, as long as it has the said characteristic, you may form using another material etc.

The air-side electrode layer is not particularly limited as long as it is generally used. For example, the air-side electrode layer can be formed from a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. The air-side electrode layer needs to have gas permeability, and the open porosity is preferably 20% or more, particularly preferably in the range of 30 to 50%.

  The support substrate is required to be gas permeable in order to permeate the fuel gas to the fuel side electrode layer, and further to be conductive in order to collect current through the interconnector. Therefore, conductive ceramics or cermets can be used as the support substrate. In producing the fuel battery cell 19, when producing a support substrate by co-firing with the fuel-side electrode layer or the solid electrolyte layer, it is preferable to form the support substrate from an iron group metal component and a specific rare earth oxide. . Further, the support substrate preferably has an open porosity of 30% or more, particularly 35 to 50% in order to have gas permeability, and its conductivity is 300 S / cm or more, particularly 440 S / cm. It is preferable that it is cm or more. Further, the shape of the support substrate may be a columnar shape, and may be a cylindrical shape.

An example of the P-type semiconductor layer is a layer made of a transition metal perovskite oxide. Specifically, a material having higher electronic conductivity than the material constituting the interconnector, for example, LaMnO ₃ -based oxide, LaFeO ₃ -based oxide, LaCoO ₃ -based oxide in which Mn, Fe, Co, etc. are present at the B site P-type semiconductor ceramics made of at least one kind of material can be used. In general, the thickness of such a P-type semiconductor layer is preferably in the range of 30 to 100 μm.

As described above, a lanthanum chromite-based perovskite oxide (LaCrO ₃ -based oxide) or a lanthanum strontium titanium-based perovskite-type oxide (LaSrTiO ₃ -based oxide) is preferably used as the interconnector. These materials have conductivity and are neither reduced nor oxidized even when they come into contact with a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air or the like). In addition, the interconnector must be dense to prevent leakage of the fuel gas flowing through the gas flow path formed in the support substrate and the oxygen-containing gas flowing outside the support substrate, 93% or more, In particular, it is preferable to have a relative density of 95% or more.

  In the module 4 including the fuel battery cell 19, particularly when the operation of the module 4 is stopped, when air is supplied to the support substrate and the fuel side electrode layer, Ni contained in the support substrate and the fuel side electrode layer is oxidized. When the module 4 is shut down, the volume of the fuel cell 19 may be expanded, thereby causing damage such as cracking of the fuel cell 19. The operation control to stop is required.

  In particular, in the operation stop of the module 4, since there are various types of operation stop such as a normal operation stop and an operation stop due to an abnormality, operation control that can cope with these various types of operation stop is required.

  It is also known to purge the inside of the module 4 using an inert gas such as nitrogen gas when the operation is stopped. In this case, a separate nitrogen gas cylinder is required, and a large amount of inert gas is contained in the purge. When necessary, there is a problem that the cylinder itself is enlarged and the fuel cell device is enlarged. Therefore, there is a demand for a fuel cell device capable of stopping and controlling the nitrogen cylinder itself with a small nitrogen cylinder.

  Therefore, in the fuel cell device of this embodiment, when the operation of the fuel cell module is stopped, the control device 7 causes the raw fuel supply line, the oxygen-containing gas supply line, the water supply according to the operation stop condition of the module 4. Control for changing supply and stop of the fluid flowing through the line and the inert gas supply line is performed. In the following description, changing the supply and stop of the fluid flowing through each line is expressed as operating or stopping each line. Needless to say, the fluid flowing through the raw fuel supply line is raw fuel, the fluid flowing through the oxygen-containing gas supply line is oxygen-containing gas, and the fluid flowing through the water supply line is water and inert gas. The fluid flowing through the supply line is an inert gas.

  4-7 is a flowchart which shows an example of the stop control of the driving | operation of the module 4 (fuel cell apparatus) of this embodiment. The operation stop control will be described below based on the flowchart shown in the figure.

  First, when starting the stop process, the control device 10 determines whether or not the start of the stop process is a process due to an abnormality of the fuel cell device in step S1. If the start of the stop process is not due to an abnormality, in other words, in the case of the normal stop process, the process proceeds to step S7 to determine whether the module temperature is lower than the first set temperature.

  Ni contained in the support substrate and the fuel-side electrode layer proceeds to NiO at a predetermined temperature or higher and becomes NiO. However, if the temperature is lower than the predetermined temperature, the oxidation reaction does not proceed (or is difficult to proceed). If the temperature is lower than the predetermined temperature, even if the operation of the raw fuel supply line, the oxygen-containing gas supply line, and the water supply line is stopped immediately, the fuel cell can be prevented from being damaged by oxidation, and efficiently The module can be shut down.

  Therefore, when the module temperature is lower than the first set temperature reflecting the predetermined temperature in step S7, the process proceeds to step S8, and the raw fuel supply line, oxygen-containing gas supply line, and water supply are continued. Control is performed to stop the operation of the lines at the same time (hereinafter, the operation of these three lines is stopped simultaneously). Thus, the fuel cell can be prevented from being damaged by oxidation, and the operation of the module can be efficiently stopped.

  On the other hand, if the module temperature is equal to or higher than the first set temperature in step S7, the process proceeds to step S9, and the raw fuel, oxygen-containing material supplied from the raw fuel supply line, oxygen-containing gas supply line, and water supply line is advanced. Control of the normal stop process for gradually decreasing the respective amounts of gas and water is performed.

  Note that the first set temperature described above may be a temperature range in which Ni oxidation does not proceed, but for the purpose of efficiently stopping the operation of the module, for example, set appropriately within a range of 300 ° C. or less, for example. Can do.

  If it is determined in step S1 that the start of the stop process is due to an abnormality in the fuel cell device, the process proceeds to step S2 to determine whether the start of the stop process is a system serious failure.

  If it is determined that there is a system serious failure, if the module shutdown process is performed over time, there is a risk of further failure of the fuel cell device during that time. It is preferable to immediately perform a shutdown process.

  The system serious failure may be appropriately set in advance according to the configuration of the fuel cell device. For example, when the temperature of the module 4 measured by the temperature measuring unit 28 is 800 ° C. or higher, Although not shown, it is possible to set the case where the cumulative concentration of CO in the fuel cell device measured by the CO concentration sensor becomes a predetermined cumulative concentration.

  If it is determined in step S2 that there is no system serious failure, the process proceeds to step S3, where it is determined whether the module temperature is lower than the first set temperature as in step S7 described above.

  If it is determined in step S3 that the module temperature is lower than the first set temperature, the raw fuel supply line, the oxygen-containing gas supply line, and the water supply line are shut down as in step S8 described above. Thus, the fuel cell can be prevented from being damaged by oxidation, and the operation of the module can be efficiently stopped.

  On the other hand, when it is determined in step S3 that the module temperature is equal to or higher than the first set temperature, what is abnormal in the fuel cell device is detected, and appropriate control is performed based on the result. Thus, the fuel cell can be prevented from being damaged by oxidation, and the operation of the module can be efficiently stopped.

  Therefore, when it is determined in step S3 that the module temperature is equal to or higher than the first set temperature, the process proceeds to step S4, where it is determined whether there is an abnormality in the oxygen-containing gas supply line.

  Whether or not there is an abnormality in the oxygen-containing gas supply line means that, for example, the supply amount of the oxygen-containing gas based on the signal transmitted from the control device 7 to the oxygen-containing gas supply pump 2 and the oxygen-containing gas flow meter 42 What is necessary is just to discriminate | determine that there exists abnormality in an oxygen containing gas supply line, when the flow volume of the measured actual oxygen containing gas is compared and the difference becomes out of a predetermined range.

  When it is determined that there is an abnormality in the oxygen-containing gas supply line, the process proceeds to step S10, where the inert gas supply line is operated to start supplying the inert gas into the module 4, and the oxygen-containing gas supply line is started. Stop the gas supply line. That is, by stopping the oxygen-containing gas supply line determined to be abnormal and starting the supply of the inert gas instead, the oxidation of the fuel cell can be more efficiently suppressed.

  Since the inert gas supply line is started and the oxygen-containing gas supply line is stopped, a large amount of air remains in the module 4 for a while, so the raw fuel supply line and the water supply line are immediately stopped. Then, an oxidation reaction may occur and the fuel cell may be damaged. Therefore, in step S10, it is preferable that the raw fuel supply line and the water supply line are continuously operated as they are.

  Then, it progresses to step S11 and it is discriminate | determined whether module temperature is less than 1st setting temperature similarly to the above-mentioned step S3,7. When the module temperature is lower than the first set temperature, the operation of the inert gas supply line, the raw fuel supply line, and the water supply line is stopped as in step S8 described above.

  On the other hand, when it is determined in step S11 that the module temperature is equal to or higher than the first set temperature, the supply of the inert gas is continued as it is. Then, it progresses to step S13 and it is discriminate | determined whether T1 minutes which are predetermined time passed since supply of the inert gas was started.

  Here, when it is determined that the time T1 has not elapsed, the process returns to step S11 again to determine whether the module temperature is lower than the first set temperature. On the other hand, when T1 minutes have elapsed, the exhaust gas line is subsequently closed.

  When control is performed to stop the operation of the inert gas supply line while the module temperature is high, the air flows backward through the exhaust gas line exhausting the exhaust gas in the module, and the fuel cell is oxidized by the air flowing backward. There is a risk that.

  Therefore, for example, an electromagnetic valve or the like is provided in the exhaust gas line, and if it is determined in step S13 that T1 minutes have passed since the supply of the inert gas has started, the electromagnetic valve is closed and the exhaust gas is discharged. It is preferable to close the line. Thereby, even if it is a case where operation | movement of an inert gas supply line is stopped in the state where module temperature is high, the backflow from an exhaust gas line can be suppressed and the oxidation of a fuel cell can be suppressed.

The predetermined time T1 minutes can be appropriately set based on the volume of the storage container constituting the module, the capacity of an inert gas cylinder (for example, a nitrogen cylinder) that stores the inert gas, etc. When the capacity of the cylinder of the inert gas is about 15 to 30 L, it is preferably set in about 1 to 10 minutes. Incidentally, in this case, when the inert gas supply line is operated and T1 minutes have elapsed, the air in the module 4 is exhausted from the exhaust gas line with the inert gas, and the inside of the module 4 is purged with the inert gas. It is preferable to set the time so that it is possible. This eliminates the need for a large inert gas cylinder and enables efficient stop processing with a small amount of inert gas.

  After the exhaust gas line is closed in step S14, the inside of the module 4 is purged with an inert gas. Therefore, the process proceeds to step S12 to operate the inert gas supply line, raw fuel supply line, and water supply line. Stop.

  If it is determined in step S4 that there is no abnormality in the oxygen-containing gas supply line, the process proceeds to step S5 to determine whether there is an abnormality in the raw fuel supply line or the water supply line.

  Whether or not there is an abnormality in the raw fuel supply line refers to, for example, the amount of raw fuel supplied based on the signal transmitted from the control device 7 to the raw fuel supply pump 1 and the actual amount measured by the raw fuel flow meter 41. Compared with the flow rate of the raw fuel, if the difference is outside the predetermined range, it may be determined that there is an abnormality in the raw fuel supply line.

  Similarly, regarding whether or not there is an abnormality in the water supply line, for example, the water supply amount based on the signal transmitted from the control device 7 to the water pump 12 and the actual water flow rate measured by the water flow meter 43 If the difference is outside the predetermined range, it may be determined that there is an abnormality in the water supply line.

  Here, when it is determined that there is no abnormality in the raw fuel supply line or the water supply line, it is determined that there is no abnormality in each of the so-called supply lines, and the process proceeds to step S6 and a normal stop process is performed.

  On the other hand, when it is determined that there is an abnormality in the raw fuel supply line or the water supply line, the process proceeds to step S15, where the inert gas line is operated and the raw fuel supply line and the water supply line are stopped. . In this case, the operation of the oxygen-containing gas supply line is preferably continued for the purpose of quickly reducing the temperature of the module.

  In step S15, after the inert gas line is operated and the control for stopping the raw fuel supply line and the water supply line is performed, the process proceeds to step S16 to determine whether the module temperature is lower than the first set temperature. Is determined.

  When it is determined in step S16 that the module temperature is lower than the first temperature, the process proceeds to step S17, and the operation of the inert gas supply line is stopped. If the temperature of the module is lower than the first set temperature, the oxidation reaction of the fuel cell does not proceed even if the inert gas is not supplied. It can suppress that the usage-amount of gas increases. During this time, the oxygen-containing gas supply line continues to operate.

  After stopping the operation of the inert gas supply line in step S17, the process proceeds to step S18 to determine whether the module temperature is lower than the second set temperature. The second set temperature is set to a temperature lower than the first set temperature, and is a temperature that does not cause any problem even if the oxygen-containing gas from the oxygen-containing gas supply line is not supplied. It can be appropriately set within the range of ° C.

If the module temperature is equal to or higher than the second set temperature in step S18, this flow is repeated. On the other hand, if the module temperature becomes lower than the second set temperature in step S18, the process proceeds to step S20, and the operation of the oxygen-containing gas supply line is stopped. Thereby, an oxygen-containing gas supply line can be stopped efficiently.

  When it is determined in step S16 that the module temperature is equal to or higher than the first set temperature, the supply of the inert gas is continued as it is. Then, it progresses to step S20 and it is discriminate | determined whether T2 minutes which are predetermined time passed since supply of the inert gas was started.

  Here, when it is determined that T2 minutes have not elapsed, the process returns to step S16 again to determine whether or not the module temperature is lower than the first set temperature. On the other hand, if it is determined in step S20 that T2 minutes have elapsed, it is determined that the inside of the module has already been purged with an inert gas, and then the process proceeds to step S21 to proceed to the oxygen-containing gas supply line. To stop. As a result, the temperature of the module 4 can be lowered with the oxygen-containing gas and the inert gas until T2 minutes, and thereafter, only the inert gas is supplied, thereby oxidizing the fuel cell. Can be suppressed.

  The T2 minutes can be set as appropriate based on the size of the fuel cell device and the like, and can be the same as the T1 minutes shown in FIG. 6, for example.

  Subsequently, after stopping the oxygen gas supply line in step S21, the process proceeds to step S22, where it is determined whether or not a predetermined time T3 has elapsed since the supply of the inert gas was started. Needless to say, T3 is longer than T2 described above.

  If it is determined in step S22 that T3 minutes have not elapsed, the process returns to S21 again, and this is repeated until T3 minutes, which is a predetermined time, have passed after the supply of the inert gas is started. return.

  On the other hand, when it is determined in step S22 that T3 minutes have elapsed, the process proceeds to step S23 to close the exhaust gas line.

  When control is performed to stop the operation of the inert gas supply line while the module temperature is high, the air flows backward through the exhaust gas line exhausting the exhaust gas in the module, and the fuel cell is oxidized by the air flowing backward. There is a risk that.

  Therefore, for example, an electromagnetic valve or the like is provided in the exhaust gas line, and if it is determined in step S22 that T3 minutes have passed since the supply of the inert gas has started, the electromagnetic valve is closed and the exhaust gas is It is preferable to close the line. Thereby, even if it is a case where operation | movement of an inert gas supply line is stopped in the state where module temperature is high, the backflow from an exhaust gas line can be suppressed and the oxidation of a fuel cell can be suppressed.

  Further, the predetermined time T3 minutes can be appropriately set based on the volume of the storage container constituting the module, the capacity of an inert gas cylinder (for example, a nitrogen cylinder) that stores the inert gas, etc. When the capacity of the cylinder of the inert gas is about 15 to 30 L, it is preferably set in about 10 to 15 minutes.

  Incidentally, in this case, when T3 minutes have passed since the inert gas supply line was operated, the air in the module 4 is exhausted from the exhaust gas line with the inert gas, and the inside of the module 4 is purged with the inert gas. It is preferable to set the time so that it is possible. This eliminates the need for a large inert gas cylinder and enables efficient stop processing with a small amount of inert gas.

  After the exhaust gas line is closed in step S23, the inside of the module 4 is purged with the inert gas, so that the process proceeds to step S24 and the operation of the inert gas supply line is stopped.

  As described above, the operation of stopping the operation of the module (fuel cell device) is performed according to the operation stop condition, and the operation and stop of the raw fuel supply line, the oxygen-containing gas supply line, the water supply line, and the inert gas supply line. By performing the control to change the fuel cell, it is possible to efficiently perform the operation stop process with a small amount of inert gas while suppressing the oxidation of the fuel cell, and to suppress the increase in size.

  FIG. 8 is an exploded perspective view showing an example of the fuel cell device of this embodiment in which the module 4 shown in FIG. 1 and an auxiliary machine (not shown) for operating the module 4 are housed in the outer case. FIG. In FIG. 8, a part of the configuration is omitted.

  The fuel cell device 44 shown in FIG. 8 divides the inside of the exterior case composed of the support columns 45 and the exterior plate 46 into upper and lower portions by a partition plate 47, and the upper side thereof serves as a module housing chamber 48 that houses the module 4 described above. The lower side is configured as an auxiliary equipment storage chamber 49 for storing auxiliary equipment for operating the module 4. In addition, the auxiliary machine stored in the auxiliary machine storage chamber 49 is omitted.

  Further, the partition plate 47 is provided with an air circulation port 50 for flowing the air in the auxiliary machine storage chamber 49 to the module storage chamber 48 side, and a part of the exterior plate 46 constituting the module storage chamber 48 is An exhaust port 51 for exhausting the air in the module storage chamber 48 is provided.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, in FIGS. 6 and 7, in the above description, the control for determining the time since the supply of the inert gas was started after the temperature of the module was previously determined was described. Control may be performed in which the time from the start of supply of the active gas is determined, and then the temperature of the module is determined. This order is particularly effective when the inert gas cylinder is small, since the amount of inert gas is small. In this case, it is preferable to set T1 to T3, which are times from the start of the supply of the inert gas, based on the capacity of the inert gas cylinder, respectively, before the capacity is turned off.

  In the above-described example, the fuel cell 19 called a so-called hollow plate type has been described. However, a horizontally striped fuel cell in which a plurality of power generation element portions generally called a horizontal stripe type are provided on a support is used. You can also.

  In the above-described example, the fuel battery cell 19 is configured to flow the fuel gas through the gas flow path, but the fuel flow path may be a fuel battery cell configured to flow the oxygen-containing gas. The same can be said.

1: Raw fuel supply pump 2: Oxygen-containing gas supply pump 3: Reformer 4: Fuel cell module 7: Control device 12: Water pump 18: Storage container 19: Fuel cell 27: Temperature measuring means (thermocouple)
52: Fuel cell device

Claims (10)

A fuel cell module in which a fuel cell that generates power with fuel gas and oxygen-containing gas is stored in a storage container;
Temperature measuring means for measuring the temperature in the fuel cell module;
A reformer for generating the fuel gas supplied to the fuel cell by steam reforming;
A raw fuel supply line for supplying raw fuel to the reformer;
A water supply line for supplying water to the reformer;
An oxygen-containing gas supply line for supplying the oxygen-containing gas to the fuel battery cell;
An inert gas supply line for supplying an inert gas into the fuel cell module;
A control device for controlling supply and stop of fluid flowing through each supply line,
The control device, when stopping the operation of the fuel cell module, according to the stop condition of the operation, the raw fuel supply line, the oxygen-containing gas supply line, the water supply line and the inert gas supply line A fuel cell device that performs control to change supply and stop of fluid flowing through the fuel cell.   In the case where the operation stop of the fuel cell module is not an operation stop due to an abnormality, and the temperature of the fuel cell module measured by the temperature measuring means is less than a first set temperature, the control device 2. The fuel cell device according to claim 1, wherein control is performed to stop supply of fluid flowing through the supply line, the oxygen-containing gas supply line, and the water supply line.   The control device is before detecting an abnormality in the raw fuel supply line, the oxygen-containing gas supply line, and the water supply line when the fuel cell module is stopped due to an abnormality. When the temperature of the fuel cell module measured by the temperature measuring unit is lower than a first set temperature, supply of fluid flowing through the raw fuel supply line, the oxygen-containing gas supply line, and the water supply line is stopped. 2. The fuel cell device according to claim 1, wherein control is performed.   When the control device detects that there is an abnormality in the oxygen-containing gas supply line, the control device stops supplying fluid flowing through the oxygen-containing gas supply line and starts supplying fluid flowing through the inert gas supply line. 4. The fuel cell device according to claim 3, wherein control is performed.   After the supply of the fluid flowing through the inert gas supply line is started, the control device supplies the raw fuel when the temperature of the fuel cell module measured by the temperature measurement unit is lower than a first set temperature. 5. The fuel cell device according to claim 4, wherein control is performed to stop supply of fluid flowing through the line, the water supply line, and the inert gas supply line.   In the case where the temperature of the fuel cell module measured by the temperature measuring unit is equal to or higher than a first set temperature, the control device has a time T1 after the supply of the fluid flowing through the inert gas supply line is started. The exhaust gas line through which the exhaust gas from the fuel cell module flows, and then the control to stop the supply of fluid flowing through the raw fuel supply line, the water supply line and the inert gas supply line. The fuel cell device according to claim 5, wherein the fuel cell device is performed.   When the control device detects that there is an abnormality in the raw fuel supply line or the water supply line, the control device starts supplying the fluid flowing through the inert gas supply line, and the raw fuel supply line and the water supply 4. The fuel cell device according to claim 3, wherein control is performed to stop supply of fluid flowing through the line.   When the temperature of the fuel cell module measured by the temperature measurement unit is lower than a first set temperature, the control device stops supplying the fluid flowing through the inert gas supply line, and the temperature measurement unit When the measured temperature of the fuel cell module becomes lower than the second set temperature set to be lower than the first set temperature, supply of the fluid flowing through the oxygen-containing gas supply line is stopped. The fuel cell device according to claim 7, wherein control is performed.   In the case where the temperature of the fuel cell module measured by the temperature measuring unit is equal to or higher than a first set temperature, the control device has a time T2 after the supply of the fluid flowing through the inert gas supply line is started. 9. The fuel cell device according to claim 8, wherein when the amount of the fuel becomes equal, control is performed to stop the supply of fluid flowing through the oxygen-containing gas supply line. The control device closes the exhaust gas line through which the exhaust gas from the fuel cell module flows when the time from the start of supplying the fluid flowing through the inert gas supply line becomes T3 minutes longer than T2 minutes. The fuel cell device according to claim 9, wherein subsequently, control is performed to stop the supply of fluid flowing through the inert gas supply line.

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