Fuel Cell Systems

Abstract

To make it possible to further suppress degradation in catalyst performance of fuel cells at low costs.SOLUTION: A fuel cell system 2 includes: a fuel cell 20 that has an anode electrode 2A, a cathode electrode 2B, and an electrolyte membrane and generates electricity when the anode electrode 2A is supplied with fuel gas and the cathode electrode 2B is supplied with oxidant gas; a catalyst equipped on at least either one electrode 2A, 2B of the anode electrode 2A and the cathode electrode 2B; gas discharge sections 35, 45 connected to an outlet of gas discharged from the one electrode 2A, 2B; discharge section opening / closing valves 36, 46 provided at the gas discharge sections 35, 45; pressurizing devices 40, 50 that pressurize the one electrode 2A, 2B; and a control section 61 that controls the opening and closing of the discharge section opening / closing valves 36, 46 and actuation of the pressurizing devices 40, 50. After the fuel cell 20 is stopped, the control section 61 actuates the pressurizing devices 40, 50 in a state in which the discharge section opening / closing valves 36, 46 are closed to pressurize the one electrode 2A, 2B.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell system suitable for use in a fuel cell vehicle or the like. [Background technology]

[0002] A fuel cell has an anode electrode (hydrogen electrode), a cathode electrode (oxygen electrode), and an electrolyte membrane disposed between these electrodes, and generates electricity by supplying a fuel gas to the anode electrode and an oxidizing gas to the cathode electrode. In such fuel cells, suppressing performance degradation has become an issue, and various technologies have been proposed.

[0003] For example, Patent Document 1 focuses on the fact that when a fuel cell vehicle is temporarily stopped and idling, the load on the fuel cell is small and the fuel cell continues to operate at a high cell voltage, which may cause the catalyst equipped on the cathode electrode to oxidize and deteriorate the catalyst performance. Patent Document 1 discloses a technology for suppressing deterioration of fuel cell performance by reducing the opening of the cathode back pressure valve during idling compared to the state before idling, thereby suppressing deterioration of catalyst performance.

[0004] Furthermore, Patent Documents 2 and 3 disclose a technology in which, when the operation of a fuel cell is stopped, compressed air generated by a compressor or the like is supplied to the anode electrode to scavenge the anode electrode and reduce the amount of moisture contained in the catalyst layer of the anode electrode, thereby suppressing catalyst deterioration due to water during shutdown or storage. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-24889 A [Patent Document 2] JP 2009-104986 A [Patent Document 3] JP 2007-73328 A Summary of the Invention [Problem to be solved by the invention]

[0006] Meanwhile, while the techniques of Patent Documents 1 to 3 make it possible to suppress the deterioration of catalyst performance, there is a demand for further suppression of the deterioration of catalyst performance and for reducing the costs associated with suppressing the deterioration of catalyst performance.

[0007] The fuel cell system of the present invention was devised in view of the above problems, and one of its objectives is to further suppress the deterioration of the catalyst performance of the fuel cell at low cost. However, this objective is not the only objective, and another objective of the present invention is to achieve the effects that are derived from the configurations shown in the below-mentioned embodiments of the invention and that cannot be obtained by the conventional techniques. [Means for solving the problem]

[0008] The fuel cell system disclosed herein includes a fuel cell having an anode electrode, a cathode electrode, and an electrolyte membrane disposed between the anode electrode and the cathode electrode, and generating power by supplying a fuel gas to the anode electrode and an oxidizing gas to the cathode electrode, a catalyst provided in at least one of the anode electrode and the cathode electrode, a gas exhaust section communicating with an outlet for gas exhausted from the one electrode, a exhaust section on-off valve provided in the gas exhaust section, a pressurizing device for pressurizing the one electrode, and a control unit for controlling opening and closing of the exhaust section on-off valve and operation of the pressurizing device. After the fuel cell is stopped, the control unit operates the pressurizing device with the exhaust section on-off valve closed to pressurize the one electrode. Furthermore, the one electrode is the cathode electrode, the gas exhaust section is an oxidant gas exhaust section communicating with an outlet for oxidant gas exhausted from the cathode electrode, the exhaust section opening / closing valve is an oxidant gas exhaust section opening / closing valve provided in the oxidant gas exhaust section, and further includes an oxidant gas inlet passage communicating with an inlet of the cathode electrode, and the pressurizing device includes an oxidant gas inlet passage pressurizing device that pressurizes the oxidant gas inlet passage by a compressor. Effect of the Invention

[0009] According to the disclosed fuel cell system, after the fuel cell is stopped, the pressure device is operated with the exhaust valve closed to pressurize the target electrode, so that the electrode is efficiently pressurized. As a result, in the electrode that has been pressurized, the amount of saturated water vapor increases, promoting a decrease in humidity, and suppressing deterioration of the catalyst due to water. In this way, since humidity can be efficiently reduced, costs can be reduced and deterioration of the catalyst performance of the fuel cell can be further suppressed. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of a main part of an electric vehicle equipped with a fuel cell system according to an embodiment; [Diagram 2] FIG. 2 is a block diagram showing a configuration of a main part of the fuel cell system shown in FIG. [Diagram 3] 2 is a flowchart illustrating the control of the fuel cell system of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The structure of a fuel cell system according to an embodiment will be described with reference to the drawings. The embodiments described below are merely examples, and are not intended to exclude various modifications or application of techniques not explicitly described in the following embodiments. Each configuration of the embodiments can be modified in various ways without departing from the spirit of the embodiments. In addition, the configurations can be selected or combined as necessary.

[0012] [1. Configuration] The fuel cell system of this embodiment is equipped in an electric vehicle, and is characterized by the control of the fuel cell system, particularly the control after the fuel cell is stopped. Below, we will first explain the overall configuration of the electric vehicle and the fuel cell system, and then explain the first pressurizing device provided in the fuel cell system, and the control in the fuel cell system using the first pressurizing device and the second pressurizing device.

[0013] [1-1. Electric vehicles and fuel cell systems] As shown in Fig. 1, an electric vehicle 1 according to this embodiment is a so-called range extender electric vehicle in which power generated by a fuel cell 20 provided in a fuel cell system 2 is charged into a secondary battery 11, and a drive motor 12 is driven by the power of the secondary battery 11. The electric vehicle 1 includes a plug-in hybrid vehicle (PHEV) that can be externally charged or externally fed. The secondary battery 11 is a chargeable and dischargeable battery, and although there is no particular limitation, for example a lithium ion battery can be used.

[0014] The fuel cell 20 is a polymer electrolyte fuel cell that is supplied with hydrogen as a fuel gas and air as an oxidizing gas, and generates electricity through an electrochemical reaction between oxygen and hydrogen. There are no particular limitations on the specific configuration of the fuel cell 20, but here, the fuel cell 20 has a stack structure in which multiple cells are stacked with separators between them.

[0015] Each cell includes an anode electrode 2A (hydrogen electrode), a cathode electrode 2B (oxygen electrode), and an electrolyte membrane (in this embodiment, a solid polymer electrolyte membrane is used as an example) disposed between them. The anode electrode 2A is composed of an electrode catalyst layer in contact with the electrolyte membrane, and a gas diffusion layer provided on the electrode catalyst layer opposite to the electrolyte membrane. Similarly, the cathode electrode 2B is also composed of an electrode catalyst layer and a gas diffusion layer. FIGS. 1 and 2 show the anode electrode 2A and the cathode electrode 2B in a schematic manner.

[0016] The electrode catalyst layer usually has catalytic activity for the electrode reactions at the anode electrode 2A and the cathode electrode 2B. Specifically, the electrode catalyst layer includes a catalyst supported on a carrier. The catalyst is not particularly limited as long as it has catalytic activity for the oxidation reaction of the fuel at the anode electrode 2A or the reduction reaction of the oxidant at the cathode electrode 2B, and any catalyst generally used in polymer fuel cells can be used. For example, platinum or an alloy of platinum and a metal (e.g., ruthenium, iron, nickel, manganese, cobalt, copper, etc.) can be used.

[0017] The support of the electrode catalyst layer of the cathode electrode 2B may be made of ceramics, and in particular, tin oxide is preferably used. Other ceramics that may be used include titanium oxide, niobium oxide, tantalum oxide, molybdenum oxide, and tungsten oxide. The support of the electrode catalyst layer of the anode electrode 2A may be made of ceramics, similar to the support of the cathode electrode 2B. In this embodiment, any of the above ceramics is used for the support of each electrode catalyst layer of the anode electrode 2A and the cathode electrode 2B. However, the support of each electrode catalyst layer is not limited to this, and for example, conductive carbon materials such as carbon particles such as carbon black and carbon fibers, and metal materials such as metal particles and metal fibers may also be used as the support.

[0018] A fuel cell 20 having such a cell is provided with an anode flow path (fuel gas flow path) consisting of a gas diffusion layer of the anode electrode 2A and a flow path communicating therewith, and a cathode flow path (oxidizing gas flow path) consisting of a gas diffusion layer of the cathode electrode 2B and a flow path communicating therewith, although details are not shown.

[0019] In addition to the fuel cell 20, the fuel cell system 2 includes a fuel gas flow system 3 connected upstream and downstream of the anode flow path on the anode electrode 2A side of the fuel cell 20, and an oxidizing gas flow system 4 connected upstream and downstream of the cathode flow path on the cathode electrode 2B side of the fuel cell 20.

[0020] The fuel gas distribution system 3 is connected in communication with, in order from upstream, a high-pressure fuel tank 30 (hereinafter referred to as "fuel tank 30") in which fuel gas (hydrogen gas) is stored, a fuel gas supply pipe 31, an anode flow path (not shown) on the anode electrode 2A side, and a fuel gas exhaust pipe 35 (fuel gas exhaust section).

[0021] The fuel gas supply pipe 31 is a flow path that connects the fuel tank 30 and the anode flow path. The fuel gas in the fuel tank 30 is supplied to the anode flow path through the fuel gas supply pipe 31. A main valve 32 and a pressure reducing valve 33 are interposed in the fuel gas supply pipe 31, in this order from upstream. The main valve 32 is a valve that opens and closes the opening of the fuel tank 30, and the pressure reducing valve 33 is a valve that reduces the pressure of the fuel gas supplied from the fuel tank 30 to a predetermined pressure to maintain a constant pressure. A first pressurizing device 50 is interposed downstream of the pressure reducing valve 33, and a downstream end 37b of the fuel recirculation flow path 37 is connected in communication between the first pressurizing device 50 and the inlet of the anode flow path.

[0022] The first pressurizing device 50 uses the pressure in the fuel tank 30 under predetermined conditions to pressurize the fuel gas introduction passage 31a, which is the inlet side portion of the anode flow passage of the fuel gas supply pipe 31, thereby pressurizing the anode flow passage and the cathode flow passage. In order to pressurize the cathode flow passage by the first pressurizing device 50, a pressure adjusting device is provided between the fuel gas supply pipe 31 and the oxidizing gas supply pipe 41 described later. , No. The first communication passage 39 is connected to the first pressure device 50, and a first on-off valve 39a is provided in the first communication passage 39. The first communication passage 39 is a component used for pressurization control, which will be described later. The details of the first pressurizing device 50 and the first communication passage 39 will be described later.

[0023] The fuel gas discharge pipe 35 is a flow path through which the fuel gas discharged from the anode flow path flows. An anode back pressure valve 36 (an anode side dead end on-off valve serving as a first discharge section on-off valve) is interposed in the fuel gas discharge pipe 35. An upstream end 37a of a fuel recirculation flow path 37 is connected in communication between the outlet of the anode flow path and the anode back pressure valve 36.

[0024] The anode back pressure valve 36 is a control valve whose opening can be adjusted as desired, and can adjust the opening (flow path area) of the fuel gas exhaust pipe 35 as desired. By adjusting the opening of the anode back pressure valve 36, it is possible to adjust the pressure of the fuel gas supplied to the anode electrode 2A of the fuel cell 20. The anode back pressure valve 36 can, of course, be opened and closed, and also functions as an opening and closing valve.

[0025] The fuel recirculation flow path 37 is connected so as to communicate with an anode flow path outlet side portion of the fuel gas discharge pipe 35 and an anode flow path inlet side portion of the fuel gas supply pipe 31. In the fuel recirculation flow path 37, a gas-liquid separator (not shown), a recirculation dead-end opening / closing valve 37c, a recirculation pump 38, and a recirculation pump downstream valve 37d are interposed in this order from an upstream end 37a to a downstream end 37b.

[0026] Water produced by the electrochemical reaction in the anode flow path and fuel gas (hydrogen gas) that did not undergo electrochemical reaction are discharged to the fuel gas discharge pipe 35. The fuel gas containing this water is separated from the water in a gas-liquid separator, and is then passed through a fuel recirculation flow path 37, where it is pressurized to a predetermined pressure by a recirculation pump 38 and sent to the fuel gas supply pipe 31. At this time, the recirculation dead-end opening / closing valve 37c is opened, and the recirculation pump downstream valve 37d is used to adjust the amount of fuel gas that re-flows from the fuel recirculation flow path 37 into the fuel gas supply pipe 31.

[0027] The oxidizing gas flow system 4 is connected in communication with an air compressor 40, an oxidizing gas supply pipe 41, a cathode flow path (not shown) on the cathode electrode 2B side, and an oxidizing gas exhaust pipe 45 (oxidizing gas exhaust section) in this order from the upstream side. The air compressor 40 is a device that takes in outside air and pressurizes it to a predetermined pressure, and has a pressure adjustment function. The air compressor 40 pressurizes an oxidizing gas introduction passage 41a, which is an inlet side portion of the cathode flow path of the oxidizing gas supply pipe 41, under predetermined conditions, and functions as a second pressurizing device that pressurizes the inside of the cathode flow path and the inside of the anode flow path. The air compressor 40 as the second pressurizing device will be described later. The above-mentioned first on-off valve 39a is also used for pressurizing the inside of the anode flow path by the second pressurizing device 40.

[0028] The oxidizing gas supply pipe 41 is a flow path that connects the air compressor 40 and the cathode flow path. In the oxidizing gas supply pipe 41, a humidified gas introduction valve 42, a humidifier 43, and a flow rate adjustment valve 44 are provided in this order from the upstream side. The humidified gas introduction valve 42 is a three-way switching valve, and can switch between a route for passing the outside air (air) pressurized to a predetermined pressure by the air compressor 40 through the humidifier 43 and a route for passing the air through a bypass path 43a without passing the air through the humidifier 43 (bypassing the humidifier 43). The reason why the introduced outside air is humidified by the humidifier 43 is to increase the conductivity of protons in the electrolyte membrane (solid polymer electrolyte membrane) by adding moisture to the air, thereby accelerating the electrochemical reaction.

[0029] The flow rate control valve 44 is a valve for adjusting the flow rate of the oxidizing gas supplied to the cathode side of the fuel cell 20. By adjusting the opening of this valve, outside air taken in from the air compressor 40 as the oxidizing gas is supplied to the cathode electrode 2B of the fuel cell 20 at a constant pressure.

[0030] The oxidizing gas exhaust pipe 45 is a flow path for exhaust gas exhausted from the cathode side of the fuel cell 20. The exhaust gas is released to the outside of the electric vehicle 1. The oxidizing gas exhaust pipe 45 is provided with a cathode back pressure valve 46 (a cathode side dead end opening / closing valve serving as a second exhaust section opening / closing valve). The cathode back pressure valve 46 is a control valve whose opening degree can be adjusted as desired. By adjusting the opening degree of the cathode back pressure valve 46, it is possible to adjust the pressure of the oxidizing gas supplied to the cathode electrode 2B of the fuel cell 20. The cathode back pressure valve 46 can naturally be opened and closed, and also functions as an opening / closing valve.

[0031] In this embodiment, outside air that has been pressurized to a predetermined pressure by the air compressor 40 is introduced and supplied to the fuel cell 20 as oxidizing gas. However, a configuration may also be adopted in which a route for directly introducing outside air and a route for introducing outside air via the air compressor 40 are provided, and the oxidizing gas may be supplied to the fuel cell 20 by switching between these routes.

[0032] Such a fuel cell 20 is a fuel cell dedicated to power generation, and is connected to the secondary battery 11 via a DC / DC converter 14. DC power generated by the fuel cell 20 is converted to a predetermined voltage by the DC / DC converter 14 and charged to the secondary battery 11. The secondary battery 11 is also connected to the drive motor 12 via an inverter 13 and the DC / DC converter 14. The DC power charged to the secondary battery 11 is converted to AC power by the inverter 13 and supplied to the drive motor 12. The drive motor 12 generates a positive drive force (torque) for driving drive wheels (not shown) using the power from the secondary battery 11. The drive motor 12 also operates as a generator when decelerating the electric vehicle 1, such as during regenerative braking, and generates a negative regenerative force (torque). This regenerative power is converted to DC power by the inverter 13 and charged to the secondary battery 11.

[0033] The charge / discharge and drive control of the fuel cell 20, secondary battery 11 and drive motor 12 is performed by an ECU 60 (Electronic Control Unit), but as this is a well-known technique, a detailed description will be omitted. The ECU 60 is composed of a microcomputer equipped with a processor (central processing unit), a main memory device (main memory, storage, etc.), an interface device, etc. (not shown). The ECU 60 is capable of receiving detection signals from various sensors.

[0034] In addition to the above-mentioned fuel cell 20, fuel gas flow system 3, and oxidizing gas flow system 4, the fuel cell system 2 includes a control unit 61 that performs a predetermined pressurization control. The control unit 61 performs pressurization control under predetermined conditions by appropriately using either the first pressurizing device 50 or the second pressurizing device 40 to pressurize the inside of the anode flow path on the anode electrode 2A side and the inside of the cathode flow path on the cathode electrode 2B side. Hereinafter, the pressurization control using the first pressurizing device 50 is also referred to as "first pressurization control," and the pressurization control using the second pressurizing device 40 is also referred to as "second pressurization control."

[0035] The control unit 61 of this embodiment is provided as a part of the functions of a program executed by the ECU 60 (functional elements within the ECU 60), and is realized, for example, by software. However, the control unit 61 may be realized by hardware (electronic circuitry) separate from the ECU 60, or may be realized by a combination of software and hardware. The configuration of the first pressurizing device 50 of this embodiment and the control of pressurization in the anode flow channel and the cathode flow channel by the control unit 61 will be described below.

[0036] [1-2. First pressure device] 1 and 2, the first pressurizing device 50 of the present embodiment includes a piston mechanism 51 provided immediately downstream of the pressure reducing valve 33, a second communication passage 52, and a third communication passage 53. That is, the first pressurizing device 50 of the present embodiment is a device that pressurizes at least the anode electrode 2A by piston compression, and is also configured to be able to pressurize the cathode electrode 2B.

[0037] The piston mechanism 51 includes a cylinder 54, a piston 55 that reciprocates within the cylinder 54, a first chamber 56 defined by the piston 55 on one side (the fuel tank 30 side) of the cylinder 54, and a second chamber 57 defined by the piston 55 on the other side (the anode electrode 2A side) of the cylinder 54. The second chamber 57 communicates with the fuel gas introduction passage 31a.

[0038] The second communication passage 52 connects the first chamber 56 and the pressure reducing valve 33, and communicates between the first chamber 56 and the fuel tank 30 via the main valve 32 and the pressure reducing valve 33. The third communication passage 53 connects the second chamber 57 and the upstream portion of the second communication passage 52, and communicates between the second chamber 57 and the fuel tank 30 via the upstream portion of the second communication passage 52, the main valve 32, and the pressure reducing valve 33. These communication passages 52, 53 constitute a part of the fuel gas supply pipe 31.

[0039] A second on-off valve 58 is provided in the second communication passage 52, and two third on-off valves 59a, 59b are provided in the third communication passage 53. When there is no need to distinguish between the two third on-off valves 59a, 59b, they are referred to as "third on-off valve 59." In this embodiment, the third on-off valves 59a, 59b are provided at both ends of the third communication passage 53, but it is sufficient that at least one third on-off valve 59 is provided at any location in the third communication passage 53. During pressurization control, which will be described later, the on-off valves 58, 59a, 59b are appropriately switched.

[0040] [1-3. Control in fuel cell systems] 1, a pressure sensor 71 for detecting the internal pressure Pa and a humidity sensor 73 for detecting the internal humidity Ha are provided in the anode flow path on the anode electrode 2A side of the fuel cell 20. A pressure sensor 72 for detecting the internal pressure Pc and a humidity sensor 74 for detecting the internal humidity Hc are provided in the cathode flow path on the cathode electrode 2B side of the fuel cell 20.

[0041] After the fuel cell 20 is stopped, the control unit 61 appropriately uses either the first pressurizing device 50 or the second pressurizing device 40 to perform pressurization control to pressurize the inside of the anode flow path and the inside of the cathode flow path. Furthermore, if the fuel cell 20 is started during the pressurization control, the control unit 61 performs a return control at the time of start-up. The return control is a control for preventing deterioration of hydrogen fuel efficiency by reusing the fuel gas (hydrogen) used in the piston compression.

[0042] The control unit 61 acquires detection signals from the above-mentioned sensors 71 to 74, and performs pressurization control based on the pressure Pa and humidity Ha in the anode flow path and the pressure Pc and humidity Hc in the cathode flow path. At this time, the control unit 61 performs pressurization control so that the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path increase to their respective target pressure ranges, and the humidity Hc is maintained at or below a certain humidity.

[0043] During this pressurization control, the control unit 61 keeps the main valve 32 open, and opens and closes the pressure reducing valve 33, the on-off valves 58, 59a, 59b immediately downstream of the pressure reducing valve 33 (see FIG. 2), the humidified gas introduction valve 42, the flow rate adjustment valve 44, the first on-off valve 39a that opens and closes the first communication passage 39, the recirculation dead-end on-off valve 37c, the recirculation pump downstream valve 37d, the anode backpressure valve 36, and the cathode backpressure valve 46 (in FIG. 1, at least two of these are collectively referred to as "valves").

[0044] An example of the pressurization control and the return control performed by the control unit 61 will be described below with reference to the flowchart of FIG. 3. The flowchart shown in FIG. 3 is performed at a predetermined control period, for example, when the main power supply of the electric vehicle 1 is on. In addition, two flags F1 and F2 are used in the following flowchart. The flag F1 is set to 1 when the first pressurization control using the first pressurization device 50 is performed, and is set to 0 when the first pressurization control is not performed (including before the control starts). In addition, the flag F2 is set to 1 when the second pressurization control using the second pressurization device 40 is performed, and is set to 0 when the second pressurization control is not performed (including before the control starts). The control unit 61 continues to acquire detection signals from the sensors 71 to 74 while the flowchart is being performed.

[0045] As shown in FIG. 3, first, the control unit 61 judges whether the fuel cell 20 is in a stopped state (step S1). If the fuel cell 20 is in a stopped state, it judges whether the flag F1 is 0 (step S2). If the flag F1 is 1, the first pressurization control has already been started and is being performed, so this flow is returned and the control is continued. On the other hand, if the flag F1 is 0, it is next judged whether the flag F2 is 0 (step S3). Here, if the flag F2 is 0, the flag F2 is set to 1 (step S4), and the second pressurization control is started (step S5). Incidentally, if the flag F2 is 1, the second pressurization control has already been started and is being performed, so this flow is returned and the control is continued.

[0046] In this embodiment, when the fuel cell 20 is stopped, the second pressurization control is first implemented, and when a predetermined end condition is met, the second pressurization control is ended, and then when a predetermined start condition is met, the first pressurization control is implemented. Therefore, the flags F1 and F2 are never both 1. The first pressurization control and the second pressurization control continue while each control is being implemented until the flags F1 and F2 are reset from 1 to 0 and it is determined that the control is ended.

[0047] In the second pressurization control, the air compressor 40 is in a pressure adjustment state, the flow rate control valve 44 is in an open state with a reference opening, the second on-off valve 58, the third on-off valve 59a, 59b, the humidified gas introduction valve 42, the recirculation dead-end on-off valve 37c, the recirculation pump downstream valve 37d, the anode back pressure valve 36, and the cathode back pressure valve 46 are all closed, and the first on-off valve 39a that opens and closes the first communication passage 39 is opened. In this state, the air compressor 40 is operated. Note that the reference opening of the flow rate control valve 44 can be the default opening when the fuel cell 20 is in operation. The pressure reducing valve 33 may be left at the default opening when the fuel cell 20 is in operation.

[0048] Furthermore, by putting the air compressor 40 into a pressure adjustment state, opening the flow rate adjustment valve 44, and closing the humidified gas introduction valve 42, the compressed outside air pressurized by the operation of the air compressor 40 is sent to the oxidant gas introduction passage 41a of the oxidant gas supply pipe 41 without being humidified, and further sent to the inside of the cathode flow path on the cathode electrode 2B side. Since the cathode back pressure valve 46 and the recirculation dead end opening / closing valve 37c on the downstream side of the cathode flow path are closed (dead end), the compressed outside air sent to the inside of the cathode flow path does not leak, and the inside of the cathode flow path is put into a high pressure state.

[0049] Furthermore, because the first communication passage 39 is opened by opening the first on-off valve 39a, the compressed outside air sent to the oxidant gas introduction passage 41a is sent to the fuel gas introduction passage 31a of the fuel gas supply pipe 31, and further sent to the inside of the anode flow passage on the anode electrode 2A side. The second on-off valve 58 and the third on-off valves 59a, 59b on the upstream side of the anode flow passage are closed, and the anode back pressure valve 36 on the downstream side of the anode flow passage is also closed, so that the compressed outside air sent to the inside of the anode flow passage does not leak out, and the inside of the anode flow passage is put into a high pressure state.

[0050] In the cathode flow channel and the anode flow channel thus pressurized, the amount of saturated water vapor increases according to the pressurized state. Even if the amount of moisture in the cathode flow channel and the anode flow channel does not decrease, the increase in the amount of saturated water vapor promotes a decrease in humidity. This second pressurization control in step S5 continues as long as flag F2 is 1.

[0051] After starting the second pressurization control in step S5, it is determined whether the pressure Pa in the anode flow path is higher than a first target pressure Pa1 (first pressure value) (Pa>Pa1) (step S6). The first target pressure Pa1 is a determination value that is set in advance as a termination condition (here, a necessary condition) of the second pressurization control. The first target pressure Pa1 is set to the upper limit value of the target pressure range or a value corresponding to the upper limit value so that the pressure Pa can be maintained within the target pressure range for a certain period of time even if the pressure Pa gradually decreases after the second pressurization control is terminated. The target pressure range is a target (ideal) pressure range that can promote a decrease in humidity within each of the electrodes 2A, 2B.

[0052] If it is determined that the pressure Pa in the anode flow path is higher than the first target pressure Pa1, then it is determined whether the pressure Pc in the cathode flow path is higher than the first target pressure Pc1 (Pc>Pc1) (step S7). This first target pressure Pc1 is also a determination value that is set in advance as a termination condition (here, a necessary condition) of the second pressurization control. The first target pressure Pc1 is set to the upper limit value of the target pressure range or a value corresponding to the upper limit value so that the pressure Pc can be maintained within the target pressure range for a certain period of time even if the pressure Pc gradually decreases after the end of the second pressurization control. The first target pressures Pa1 and Pc1 on the anode side and cathode side may be set according to the characteristics and properties of each electrode 2A and 2B, and may be different values ​​or the same value.

[0053] When the pressure Pa in the anode flow path is higher than the first target pressure Pa1 and the pressure Pc in the cathode flow path is higher than the first target pressure Pc1, it is determined that both flow paths have reached a sufficiently high pressure, and the flag F2 is reset to 0 (step S8), the air compressor 40 is stopped, and the second pressurization control is terminated (step S9). At this time, the open / closed states of the valves set at the start of the second pressurization control may be maintained, but it is preferable to close the flow rate adjustment valve 44 between the air compressor 40 and the oxidizing gas introduction path 41a so that the compressed air in the oxidizing gas introduction path 41a does not leak to the stopped air compressor 40 side.

[0054] Furthermore, if either the pressure Pa in the anode flow path or the pressure Pc in the cathode flow path is not higher than the first target pressure Pa1, Pc1, the flow returns from step S6 or S7. In this case, since flag F2 is 1, if the stopped state of the fuel cell continues, the flow proceeds to step S5 again in the next control period and the second pressurization control continues. As a result, both the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path are adjusted toward or near the upper limit value of the target pressure range.

[0055] When the second pressure control ends in step S9, it is determined whether the pressure Pa in the anode flow path is lower than the second target pressure Pa2 (second pressure value) (Pa < Pa2) (step S10). The second target pressure Pa2 is a determination value preset as one of the start conditions of the first pressure control, and is set to the lower limit value of the target pressure range or a value corresponding to the lower limit value. If it is determined that the pressure Pa in the anode flow path is lower than the second target pressure Pa2, the flag F1 is set to 1 (step S14), and the first pressure control is started (step S15).

[0056] Also, when the pressure Pa in the anode flow path is not lower than the second target pressure Pa2, it is determined whether the pressure Pc in the cathode flow path is lower than the second target pressure Pc2 (Pc < Pc2) (step S11). The second target pressure Pc2 is also a determination value preset as one of the start conditions of the first pressure control, and is set to the lower limit value of the target pressure range or a value corresponding to the lower limit value. Note that the second target pressures Pa2 and Pc2 on the anode side and the cathode side may be set according to the characteristics and properties of the respective electrodes 2A and 2B, and may be different values or the same value. If it is determined that the pressure Pc in the cathode flow path is lower than the second target pressure Pc2, the flag F1 is set to 1 (step S14), and the first pressure control is started (step S15).

[0057] When both the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path are not lower than the second target pressures Pa2 and Pc2, it is determined whether the humidity Ha in the anode flow path is higher than the upper limit humidity Ha1 (Ha > Ha1) (step S12). The upper limit humidity Ha1 is a determination value preset as one of the start conditions of the first pressure control, and is set as the allowable upper limit value of the humidity in the anode flow path. If it is determined that the humidity Ha in the anode flow path is higher than the upper limit humidity Ha1, the flag F1 is set to 1 (step S14), and the first pressure control is started (step S15).

[0058] If the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path are not lower than the second target pressures Pa2, Pc2, and the humidity Ha in the anode flow path is not higher than the upper limit humidity Ha1, it is determined whether the humidity Hc in the cathode flow path is higher than the upper limit humidity Hc1 (Hc>Hc1) (step S13). The upper limit humidity Hc1 is also a determination value that is set in advance as one of the start conditions for the first pressurization control, and is set as the allowable upper limit value of the humidity in the cathode flow path. The upper limit humidity Ha1, Hc1 on the anode side and the cathode side may be set according to the characteristics and properties of each electrode 2A, 2B, and may be different values ​​or the same value.

[0059] If it is determined that the humidity Hc in the cathode flow path is higher than the upper limit humidity Hc1, the flag F1 is set to 1 (step S14), and the first pressurization control is started (step S15). If the humidity Hc in the cathode flow path is not higher than the upper limit humidity Hc1, that is, if all of steps S10 to S13 are determined to be "No", this flow is returned and the first pressurization control is not started.

[0060] Therefore, when it is determined that either the pressure Pa in the anode flow path or the pressure Pc in the cathode flow path is lower than the second target pressure Pa2, Pc2, the first pressurization control is started. In addition, even if neither the pressure Pa in the anode flow path nor the pressure Pc in the cathode flow path is lower than the second target pressure Pa2, Pc2, when it is determined that either the humidity Ha in the anode flow path or the humidity Hc in the cathode flow path is higher than the upper limit humidity Ha1, Hc1, the first pressurization control is started.

[0061] In the first pressurization control, the pressure reducing valve 33 is opened to a reference opening degree, the third on-off valves 59a and 59b, the humidified gas introduction valve 42, the recirculation dead-end on-off valve 37c, the recirculation pump downstream valve 37d, the anode back pressure valve 36, and the cathode back pressure valve 46 are all closed, and the second on-off valve 58 is opened to ensure the fuel gas route R2 shown in FIG. 2. The route R2 is a piston compression line that introduces high-pressure fuel gas into the first chamber 56 during the first pressurization control. In addition, the first on-off valve 39a that opens and closes the first communication passage 39 is opened. The reference opening degree of the pressure reducing valve 33 can be the default opening degree during operation of the fuel cell 20. It is preferable to close the flow rate adjustment valve 44.

[0062] By opening the second on-off valve 58, high-pressure fuel gas flows into the first chamber 56 of the cylinder 54, and by pressing the piston 55, the second chamber 57 of the cylinder 54 is pressurized to the same pressure as the fuel gas. Then, the inside of the fuel gas inlet passage 31a communicating with the second chamber 57 is also pressurized, and the inside of the oxidizing gas inlet passage 41a of the oxidizing gas supply pipe 41 is also pressurized through the first communication passage 39.

[0063] As a result, the inside of the anode flow passage on the anode electrode 2A side and the inside of the cathode flow passage on the cathode electrode 2B side are pressurized. Since the third on-off valves 59a, 59b on the upstream side of the anode flow passage are closed and the anode back pressure valve 36 on the downstream side of the anode flow passage is also closed (dead end), the compressed outside air sent to the inside of the anode flow passage does not leak and the inside of the anode flow passage is put into a high pressure state. In addition, since the third on-off valves 59a, 59b on both ends of the third communication passage 53 are both closed, the inside of the third communication passage 53 is not unnecessarily pressurized and the pressure of the fuel gas can be efficiently used.

[0064] Meanwhile, the flow rate control valve 44 on the upstream side of the cathode flow path is closed, and the cathode back pressure valve 46 and the recirculation dead end opening / closing valve 37c on the downstream side of the cathode flow path are also closed, so that the fuel gas sent to the inside of the cathode flow path does not leak, and the inside of the cathode flow path is put into a high pressure state. Inside the cathode flow path and the anode flow path thus pressurized, the amount of saturated water vapor increases according to the pressurized state. Even if the amount of moisture inside the cathode flow path and the anode flow path does not decrease, the increase in the amount of saturated water vapor promotes a decrease in humidity. This first pressurization control in step S15 continues as long as flag F1 is 1.

[0065] On the other hand, when the fuel cell 20 is started from a stopped state, the process proceeds to step S16 based on the determination in step S1, and it is determined whether or not the flag F1 is 1. If it is determined that the flag F1 is 1, the flag F1 is reset to 0 (step S17), and the first pressurization control is terminated (step S18). Then, in conjunction with the termination of the first pressurization control, recovery control is implemented (step S19), and this flow returns.

[0066] To end the first pressurization control following the start-up of the fuel cell 20, the pressure reducing valve 33 is opened to a reference opening (for example, a default opening), and the third on-off valves 59a, 59b are opened to ensure the fuel gas supply route R1 shown in FIG. 2. At this time, the anode back pressure valve 36 and the cathode back pressure valve 46 are both opened to the reference opening or the like, and the first on-off valve 39a that opens and closes the first communication passage 39 is closed. The route R1 is a reuse line that recovers the fuel gas used in the first pressurization control during return control and reuses it for normal power generation. In the route R1, the fuel gas flows back through a part of the second communication passage 52 and flows into the third communication passage 53.

[0067] In the return control, the normal route R3 shown in Fig. 2 is secured, and the fuel gas used in the piston compression is circulated through the normal route R3 to prevent a deterioration in fuel efficiency. The normal route R3 is a line through which the fuel gas passes when the fuel cell 20 is operating. While the fuel cell 20 is operating, the second on-off valve 58 is closed, but in the return control, the second on-off valve 58 is kept open for a predetermined very short time immediately after the start-up of the fuel cell 20, and then the second on-off valve 58 is closed. The humidified gas introduction valve 42 is opened appropriately based on a subsequent request for humidification, etc. The recirculation dead-end opening / closing valve 37c and the recirculation pump downstream valve 37d are also opened appropriately based on a subsequent request for fuel gas recirculation, etc.

[0068] That is, during the first pressurization control, the third on-off valves 59a, 59b at both ends of the third communication passage 53 are both closed, and the inside of the third communication passage 53 is not pressurized. Therefore, the inside of the third communication passage 53 is at a lower pressure than the part between the pressure reducing valve 33 and the second on-off valve 58 of the fuel gas supply pipe 31 and the inside of the first chamber 56 of the cylinder 54. For this reason, when the third on-off valves 59a, 59b are opened, the fuel gas flows into the third communication passage 53 from the part between the pressure reducing valve 33 and the second on-off valve 58 of the fuel gas supply pipe 31. At this time, if the second on-off valve 58 is open, the fuel gas in the first chamber 56 also flows into the third communication passage 53.

[0069] It is considered that the fuel gas in the first chamber 56 flows into the third communication passage 53 for a short time immediately after the third on-off valves 59a, 59b are opened, and the fuel gas used in the piston compression can be circulated through the route R1 simply by holding the second on-off valve 58 in an open state for a predetermined very short time immediately after the third on-off valves 59a, 59b are opened. If the second on-off valve 58 is closed after the predetermined very short time has elapsed, the route R1 is closed, and only the normal route R3 needs to be used.

[0070] On the other hand, if it is not determined in step S16 that the flag F1 is 1, the process proceeds to step S20, where it is determined whether or not the flag F2 is 1. If it is determined that the flag F2 is 1, the flag F2 is reset to 0 (step S21), and the second pressurization control is terminated (step S22).

[0071] At the end of the second pressurization control, the fuel cell 20 is started, so the air compressor 40 may be driven based on an operation request of the fuel cell 20. In this case, the pressure reducing valve 33 is opened to a reference opening degree (for example, a default opening degree), the third opening / closing valves 59a and 59b are opened, the anode back pressure valve 36 and the cathode back pressure valve 46 are both opened to the reference opening degree or the like, and the first opening / closing valve 39a that opens and closes the first communication passage 39 is closed, and the flow is returned.

[0072] In this embodiment, during the first pressurization control, the pressure reducing valve 33 is opened to the reference opening degree, and the opening degree is not changed. However, if the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path do not reach the target value (for example, the third target pressure Pa3, Pc3 set as an intermediate value between the first target pressure Pa1, Pc1 and the second target pressure Pa2, Pc2) even after a predetermined time has elapsed after the start of the first pressurization control, the opening degree of the pressure reducing valve 33 may be increased by a predetermined amount from the reference opening degree. In this case, if the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path do not reach the target value even after a predetermined time has elapsed since the opening degree of the pressure reducing valve 33 was increased by a predetermined amount from the reference opening degree, the opening degree of the pressure reducing valve 33 may be further increased by a predetermined amount. According to such control, the pressures Pa and Pc can be reliably increased.

[0073] [2. Actions and Effects] (1) In the fuel cell system 2 according to the embodiment, after the fuel cell 20 is stopped, the anode back pressure valve 36 as the anode side dead end valve (first discharge part valve) and the cathode back pressure valve 46 as the cathode side dead end valve (second discharge part valve) are closed, and the pressurizing device (first pressurizing device 50 or second pressurizing device 40) is operated to pressurize the inside of the anode flow path of the anode electrode 2A and the inside of the cathode flow path of the cathode electrode 2B. Therefore, the pressure does not escape from the gas discharge parts 35, 45, and the inside of the electrodes 2A, 2B can be efficiently pressurized. As a result, in the electrodes 2A, 2B that have become high pressure, the humidity reduction is promoted by the increase in the amount of saturated water vapor, and the deterioration of the catalyst due to water can be suppressed. In this way, since the humidity can be efficiently reduced, the cost can be reduced, and the deterioration of the catalyst of the fuel cell 20 can be further suppressed. Therefore, the deterioration of the performance and the deterioration of the durability of the fuel cell 20 can be suppressed.

[0074] In other words, when the fuel cell 20 is stopped, as the temperature inside the electrodes 2A, 2B drops thereafter, some of the water vapor inside condenses into water. When water and oxygen are adsorbed onto a catalytic metal (e.g., platinum Pt or an alloy of platinum Pt and a different metal), oxidation of the surface progresses, causing the catalyst to dissolve and become coarse, resulting in a deterioration in the power generation performance of the fuel cell and a decrease in the durability of the fuel cell. For this reason, while the fuel cell 20 is stopped, the power generation performance of the fuel cell and the durability of the fuel cell are likely to deteriorate.

[0075] In contrast, in the present fuel cell system 2, the inside of the electrodes 2A, 2B is efficiently pressurized, so the amount of saturated water vapor in the high-pressure electrodes 2A, 2B increases, accelerating the decrease in humidity. When the humidity in the electrodes 2A, 2B decreases, condensation of water vapor in the electrodes 2A, 2B is suppressed, and an increase in moisture in the electrodes 2A, 2B is suppressed. This suppresses oxidation of the surface of the catalytic metal, and further suppresses deterioration in performance and durability of the fuel cell 20.

[0076] (2) By using the first pressurizing device 50, which uses the pressure of the fuel gas in the fuel tank 30 to pressurize the inside of the fuel gas introduction passage 31a, the operating costs of the system required for pressurization can be reduced. (3) By using the first communication passage 39 that connects the fuel gas inlet passage 31a and the oxidant gas inlet passage 41a, the pressure of the fuel gas can be introduced into the oxidant gas inlet passage 41a as well, and thus not only the anode electrode 2A but also the cathode electrode 2B can be pressurized, so that both electrodes 2A, 2B can be efficiently pressurized.

[0077] (4) Furthermore, by using the existing air compressor 40 (second pressurizing device) in the fuel cell 20 as a pressurizing device to pressurize the inside of the oxidizing gas introduction passage 41a, the equipment costs required for the pressurization can be reduced. (5) By using the first communication passage 39 that connects the fuel gas inlet passage 31a and the oxidant gas inlet passage 41a, compressed air compressed by the air compressor 40 can be introduced into the fuel gas inlet passage 31a as well, thereby pressurizing not only the cathode electrode 2B but also the anode electrode 2A, and therefore both electrodes 2A, 2B can be efficiently pressurized.

[0078] (6) When the fuel cell 20 is stopped, the control unit 61 performs the second pressurization control by the second pressurization device 40, and then when a predetermined end condition is met, the control unit 61 stops the second pressurization device 40, and then when a predetermined start condition is met, the control unit 61 performs the first pressurization control by the first pressurization device 50 to pressurize the anode electrode 2A and the cathode electrode 2B. Therefore, first, the pressure drop in each electrode 2A, 2B immediately after the fuel cell 20 is stopped is suppressed by active pressurization by the second pressurization device 40, and thereafter, the pressure drop in each electrode 2A, 2B is suppressed by pressurization by the first pressurization device 50 with reduced operating costs, thereby enabling both electrodes 2A, 2B to be efficiently pressurized at low cost.

[0079] (7) The condition for ending the second pressurization control is that the internal pressures Pa, Pc of the fuel cell 20 detected by the pressure sensors 71, 72 are higher than the first target pressures Pa1, Pc1 (first pressure values) (steps S6, S7). Therefore, the second pressurization control can be ended with the internal pressures Pa, Pc of the fuel cell 20 being sufficiently high, and the pressures of both electrodes 2A, 2B can be maintained at a certain level or higher even after the second pressurization control is ended.

[0080] (8) The condition for starting the first pressurization control is that the internal pressures Pa, Pc of the fuel cell 20 detected by the pressure sensors 71, 72 are lower than second target pressures Pa2, Pc2 (second pressure values) (steps S10, S11). Therefore, the first pressurization control can be started before the internal pressures Pa, Pc of the fuel cell 20 drop excessively, and the first pressurization control can maintain the pressures of both electrodes 2A, 2B at or above a certain level.

[0081] (9) The first pressurizing device 50 includes a piston mechanism 51, a second communication passage 52, a third communication passage 53, a second on-off valve 58, and a third on-off valve 59. The control unit 61 can pressurize the first pressurizing device 50 by opening the second on-off valve 58 and closing the third on-off valve 59. This makes it possible to utilize the pressure of the fuel gas in the fuel tank 30 at low cost.

[0082] (10) The fuel cell 20 is a power generating fuel cell mounted on the electric vehicle 1. Power generating fuel cells are stopped for a relatively long period of time, and therefore the deterioration of the catalyst due to water remaining or condensing on the electrodes 2A, 2B during the stopped period is likely to be accelerated accordingly. In contrast, the fuel cell system 2 can suppress such catalyst deterioration at low cost.

[0083] (11) The catalysts provided on the anode electrode 2A and the cathode electrode 2B of the fuel cell 20 are ceramic catalysts in which ceramics are used as carriers for the electrode catalyst layers. In the case of ceramic catalysts, applying pressure to the electrodes 2A, 2B increases the fuel cell resistance and makes it difficult for current to flow, thereby suppressing the reaction of the residual gases at the electrodes 2A, 2B, which also helps to suppress catalyst deterioration.

[0084] (Other effects) In this embodiment, the second pressurization control is terminated when both the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path are higher than the first target pressures Pa1 and Pc1. Therefore, the second pressurization control can increase the pressures in both the anode flow path and the cathode flow path to near the upper limits of the target pressure ranges, making it easier to maintain a high pressure state inside both electrodes 2A and 2B even when the second pressurization control is stopped.

[0085] In this embodiment, when either the pressure Pa in the anode flow path or the pressure Pc in the cathode flow path drops to the second target pressure Pa2, Pc2, the first pressurization control is started, so that both the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path can be maintained at or above the second target pressure Pa2, Pc2.

[0086] Furthermore, in this embodiment, as the start condition of the first pressurization control, attention is paid not only to the pressure Pa in the anode flow path and the pressure Pc in the cathode flow path, but also to the humidity Ha in the anode flow path and the humidity Hc in the cathode flow path. That is, even if neither the pressure Pa in the anode flow path nor the pressure Pc in the cathode flow path has decreased to the second target pressures Pa2 and Pc2, when either the humidity Ha in the anode flow path or the humidity Hc in the cathode flow path has increased to the upper limit humidity Ha1 and Hc1, the first pressurization control is started. Therefore, for example, in a situation where there is a lot of residual water and the humidity is high even if the pressures Pa and Pc have not decreased, the performance deterioration and durability deterioration of the catalyst are likely to occur, but such a problem can be avoided.

[0087] [3.Other] The above-mentioned configuration of the fuel cell system 2 is an example, and is not limited to the above. For example, in the above embodiment, both the anode electrode 2A and the cathode electrode 2B are pressurized, but if only one of the electrodes is easily deteriorated by water, only the electrode that is easily deteriorated may be pressurized. In this case, flow paths and valves necessary for the object to be pressurized are provided, and the others can be omitted.

[0088] In the above embodiment, when the fuel cell 20 is stopped, the second pressurization control is first performed, and when a predetermined end condition is satisfied, the second pressurization control is terminated, and then when a predetermined start condition is satisfied, the first pressurization control is performed, but either one or both of the anode electrode 2A and the cathode electrode 2B may be pressurized using only the air compressor 40 (second pressurization device). In the second pressurization control, electricity (operation cost) is required to operate the air compressor 40, but since the anode back pressure valve 36 and the cathode back pressure valve 46 are closed to operate the air compressor 40, leakage of compressed air is suppressed, the operation efficiency of the air compressor 40 can be increased, and the operation cost can be suppressed.

[0089] Alternatively, either or both of the anode electrode 2A and the cathode electrode 2B may be pressurized using only the first pressurizing device 50 that uses the pressure of the fuel gas in the fuel tank 30. The first pressurizing device 50 does not require electricity (operation cost) to operate the air compressor 40, and uses the pressure of the fuel tank 30 by closing the anode back pressure valve 36 and the cathode back pressure valve 46, thereby suppressing leakage of the fuel gas pressure and making effective use of the fuel gas pressure.

[0090] It is also possible to use only the second pressurizing device 40 (air compressor) to pressurize only the cathode electrode 2B, or to use only the first pressurizing device 50 to pressurize only the anode electrode 2A. In such cases, the first communication passage 39 and the first on-off valve 39a can be omitted. Furthermore, the start conditions and end conditions of the first pressurization control and the start conditions and end conditions of the second pressurization control are not limited to those in the above embodiment, and can be set appropriately.

[0091] In the above embodiment, a ceramic catalyst is used as the catalyst, but the catalyst is not limited to a ceramic catalyst. For example, a carbon catalyst using carbon as a carrier may also be used in this fuel cell system. Furthermore, the fuel cell 20 is not limited to a fuel cell for generating electricity that is equipped on the electric vehicle 1, but may be a fuel cell for propulsion, or may be a fuel cell used for both generating electricity and propulsion. Furthermore, the present fuel cell system is not limited to one that is mounted on a vehicle. Furthermore, by combining the technology of the fuel cell system of the present invention with the conventional technologies described in, for example, Patent Documents 1 to 3, it is possible to further suppress the deterioration of the catalyst performance and the decrease in durability of the fuel cell at low cost. [Explanation of symbols]

[0092] 1 Electric vehicles 2. Fuel Cell System 2A Anode electrode (hydrogen electrode) 2B Cathode electrode (oxygen electrode) 20 Fuel Cell 30 High-pressure fuel tank 31a Fuel gas inlet 35 Fuel gas exhaust pipe (fuel gas exhaust section) 36 Anode back pressure valve (first discharge section opening / closing valve) 39 First series of aisles 39a First shutoff valve 40 Air compressor (secondary pressure device) 41a Oxidizing gas inlet 45 Oxidizing gas exhaust pipe (Oxidizing gas exhaust section) 46 Cathode back pressure valve (second discharge section opening / closing valve) 50 First pressure device 51 Piston mechanism 52 Second communication passage 53 Third passageway 54 Cylinder 55 Piston 56 Room 1 57 Second room 58 Second on-off valve 59, 59a, 59b Third opening and closing valve 61 Control section 71,72 Pressure Sensors Pa Pressure in the anode flow passage (pressure at the anode electrode) Pa1 First target pressure (first pressure value) Pa2 Second target pressure (second pressure value) Pc Pressure in the cathode flow passage (cathode electrode pressure) Pc1 First target pressure (first pressure value) Pc2 Second target pressure (second pressure value)

Claims

1. a fuel cell having an anode electrode, a cathode electrode, and an electrolyte membrane disposed between the anode electrode and the cathode electrode, the fuel cell generating power by supplying a fuel gas to the anode electrode and an oxidizing gas to the cathode electrode; a catalyst provided on at least one of the anode electrode and the cathode electrode; a gas exhaust portion communicating with an outlet for gas exhausted from the one electrode; A discharge part opening / closing valve provided in the gas discharge part; a pressure device for applying pressure to the one electrode; A control unit that controls opening and closing of the discharge unit opening / closing valve and operation of the pressurizing device, the control unit operates the pressurizing device to pressurize the one electrode while closing the exhaust unit opening / closing valve after the fuel cell is stopped, The one electrode is the cathode electrode, The gas exhaust unit is an oxidizing gas exhaust unit communicating with an outlet for oxidizing gas exhausted from the cathode electrode, The exhaust section on-off valve is an oxidizing gas exhaust section on-off valve provided in the oxidizing gas exhaust section, Further, an oxidizing gas introduction passage communicating with the inlet of the cathode electrode is provided, The pressurizing device includes an oxidizing gas introduction passage internal pressurizing device that pressurizes the inside of the oxidizing gas introduction passage by a compressor. A fuel cell system comprising:

2. A catalyst provided on the anode electrode; a fuel gas discharge portion communicating with an outlet of the fuel gas discharged from the anode electrode; a fuel gas discharge part on-off valve provided in the fuel gas discharge part; a fuel gas introduction passage communicating with an inlet of the anode electrode; a first communication passage that communicates the fuel gas introduction passage and the oxidizing gas introduction passage; a first on-off valve provided in the first communication passage, After the fuel cell is stopped, the control unit closes the fuel gas discharge valve and the oxidant gas discharge valve, and operates the oxidant gas introduction passage internal pressurizing device in a state in which the first open / close valve is opened to pressurize the anode electrode and the cathode electrode.

2. The fuel cell system according to claim 1 .

3. The catalyst provided on the anode electrode; a fuel gas discharge portion communicating with an outlet of the fuel gas discharged from the anode electrode; a fuel gas discharge part on-off valve provided in the fuel gas discharge part; a fuel gas introduction passage communicating with an inlet of the anode electrode; a first communication passage that communicates the fuel gas introduction passage and the oxidizing gas introduction passage; a first on-off valve provided in the first communication passage, the pressurizing device includes a fuel gas introduction channel internal pressurizing device that pressurizes an inside of the fuel gas introduction channel using a pressure in a high-pressure fuel tank that stores a fuel gas to be supplied to the anode electrode, The control unit performs pressurization control to pressurize the anode electrode and the cathode electrode by operating the pressurizing device in the oxidant gas introduction passage while closing the fuel gas discharge part on-off valve and the oxidant gas discharge part on-off valve and opening the first on-off valve, and then, when a predetermined end condition is met, stops the pressurizing device in the oxidant gas introduction passage while maintaining the fuel gas discharge part on-off valve and the oxidant gas discharge part on-off valve closed and the first on-off valve open, and then, when a predetermined start condition is met, performs another pressurization control to pressurize the anode electrode and the cathode electrode by operating the pressurizing device in the fuel gas introduction passage.

2. The fuel cell system according to claim 1 .

4. a pressure sensor for detecting an internal pressure of the fuel cell; The termination condition is that the pressure detected by the pressure sensor is higher than a preset first pressure value.

4. The fuel cell system according to claim 3 .

5. a pressure sensor for detecting an internal pressure of the fuel cell; The start condition is that the pressure detected by the pressure sensor is lower than a preset second pressure value.

5. The fuel cell system according to claim 3 or 4.

6. The fuel gas introduction passage internal pressurizing device is a piston mechanism including a cylinder, a piston reciprocating within the cylinder, a first chamber defined by the piston on one side within the cylinder, and a second chamber defined by the piston on the other side within the cylinder and communicating with the fuel gas introduction passage; a second communication passage communicating the first chamber with the high-pressure fuel tank; a third communication passage communicating the second chamber with the high-pressure fuel tank; a second on-off valve disposed in the second communication passage; a third on-off valve provided in the third communication passage, The control unit causes the fuel gas introduction passage internal pressurizing device to perform a pressurizing operation while opening the second on-off valve and closing the third on-off valve.

6. The fuel cell system according to claim 3, wherein the fuel cell system comprises:

7. The fuel cell is a fuel cell for generating electricity that is installed in a vehicle.

7. The fuel cell system according to claim 1, wherein the fuel cell system comprises:

8. The catalyst is a ceramic catalyst.

8. The fuel cell system according to claim 1, wherein the fuel cell system comprises:

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