JP2009117319A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of preventing the freezing of a cathode exhaust path after starting normal operation. <P>SOLUTION: When an oxidizer gas exhaust flow passage R is brought into a closed state by the freezing, the detected value of a pressure sensor 72 is output to a pressure instruction value (opening of back pressure valve 36) determined by the detected value of a throttle opening sensor 73 at a high level. Then, when it is determined that the oxidizer gas exhaust flow passage R is the closed state, the determination due to the closed state is distinguished from the determination due to the auxiliary machine failure by the detected value of an outside air temperature sensor 75. In the case of the closed state, when the detected value of a current sensor 74 does not exceed a predetermined value, the high temperature air bypassing a cooler 32 is supplied to a fuel cell FC and the idling stop is inhibited. Moreover, when the detected value of the current sensor 74 exceeds the predetermined value, the air not bypassing the cooler 32 is supplied to the fuel cell FC and the idling stop is inhibited. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system capable of preventing freezing during normal operation.

In the fuel cell system, various techniques for warming up the fuel cell have been proposed in order to improve the startability of the fuel cell in a low temperature (below freezing point) environment. Fuel cell vehicles and the like are required to promptly warm up from the standpoint of merchantability. For example, the fuel cell is heated by supplying air that has been heated to a high temperature by a compressor. A technique for quickly performing the machine has been proposed (see Patent Document 1).
JP 2002-134150 A (paragraphs 0038 and 0043)

  However, when the fuel cell system is used in an environment where the temperature is below freezing point, the generated water discharged from the fuel cell or the wet water is wet even after the warm-up operation of the fuel cell is completed and the normal operation is started. There was a problem that the moisture in the cathode off-gas in a frozen state freezes in the piping. This is because, even after warming up, the temperature of pipes and the like rapidly decreases depending on the environment, which not only deteriorates the power generation performance but also may cause problems such as piping of the fuel cell system.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a fuel cell system capable of preventing icing of the cathode discharge path after the start of normal operation.

  According to a first aspect of the present invention, there is provided a fuel cell that generates power by being supplied with an oxidant gas and a fuel gas, an oxidant gas supply unit that supplies the fuel cell with an oxidant gas, and an oxidant discharged from the fuel cell. A fuel cell system comprising: an oxidant gas discharge passage through which an agent gas is circulated and discharged; and a fuel cell warm-up completion determination unit that determines whether or not the fuel cell has been warmed up. A discharge flow path state determining means for determining whether or not the oxidant gas discharge flow path is closed due to freezing; and a discharge flow path deicing means for eliminating the closed state due to freezing of the oxidant gas discharge flow path And the fuel cell warm-up completion determining means determines that the fuel cell has been warmed up, and then the exhaust flow path state determining means determines that the oxidant gas discharge flow path is closed. The discharge channel de-icing means And performing control for thawing more the oxidizing gas discharging passage.

  According to the first aspect of the present invention, even when the inside of the oxidant gas discharge channel is closed due to freezing of the produced water after the warm-up is completed in a low temperature (below freezing) environment, Since the deicing control in the oxidant gas discharge channel is performed based on the blocked state, it is possible to perform the deicing in the oxidant gas discharge channel, and the oxidant gas discharge channel is eliminated by eliminating the blocked state. It becomes possible to prevent a decrease in power generation performance due to freezing inside and problems with piping and the like.

  According to a second aspect of the present invention, the discharge channel state determination means is configured to block the oxidant gas discharge channel based on a pressure command value of the cathode channel and a pressure value detected by the cathode channel. It is characterized by judging.

  According to the second aspect of the invention, the closed state in the oxidant gas discharge channel is detected in order to detect the closed state of the oxidant gas discharge channel based on the pressure command value and the detected pressure value. Without using a special device, it is possible to estimate the closed state of the oxidant gas discharge channel by detecting the pressure with the pressure sensor.

  According to a third aspect of the present invention, the discharge channel state determining means is configured to block the oxidant gas discharge channel based on a flow rate command value of the cathode channel and a flow rate value detected by the cathode channel. It is characterized by judging.

  According to the third aspect of the invention, the closed state in the oxidant gas discharge flow path is detected in order to detect the closed state of the oxidant gas discharge flow path based on the flow rate command value and the detected flow rate value. It is possible to estimate the closed state of the oxidant gas discharge channel by detecting the flow rate with a flow rate sensor without using a special device.

  The invention according to claim 4 is characterized in that the discharge flow path state determining means determines the closed state of the oxidant gas discharge flow path based on feedback with respect to a back pressure valve opening command value.

  According to the invention of claim 4, it is possible to estimate the closed state of the oxidant gas discharge flow path by feedback of the back pressure valve without using a special device for detecting the closed state in the oxidant gas discharge flow path. It becomes possible.

  The invention according to claim 5 is characterized in that the discharge flow path state determining means determines the closed state of the oxidant gas discharge flow path based on feedback with respect to a rotation speed command value of the air compressor.

  According to the invention which concerns on Claim 5, the obstruction | occlusion state of an oxidant gas discharge flow path can be estimated by the feedback of an air compressor, without using the special apparatus which detects the obstruction | occlusion state in an oxidant gas discharge flow path. It becomes possible.

  The invention according to claim 6 includes a heat exchanger that is provided in a gas flow path between the oxidant gas supply means and the fuel cell, and that cools the oxidant gas supplied to the fuel cell. The channel deicing means supplies the oxidant gas from the oxidant gas supply means to the fuel cell by bypassing the heat exchanger.

  According to the invention of claim 6, since the heat exchanger is bypassed, the oxidant gas (cathode off-gas) discharged from the fuel cell is discharged to the outside of the fuel cell system (outside the system) before falling to the freezing temperature. Is done. For this reason, it is possible to prevent the water contained in the generated water and the wet oxidant gas discharged from the fuel cell after the start of power generation from icing in the oxidant gas discharge flow path, or even if the water is frozen, it can be defrosted. As a result, it is possible to prevent the oxidant gas discharge flow path (pipe, etc.) from being damaged due to freezing.

  The invention according to claim 7 is characterized in that the discharge channel deicing means is a power generation amount increasing means for increasing the power generation amount of the fuel cell.

  According to the seventh aspect of the invention, by increasing the amount of power generated by the fuel cell, the amount of self-heating of the fuel cell increases, and the temperature of the oxidant gas (off-gas) discharged from the fuel cell increases. Therefore, even if a clogging phenomenon due to freezing occurs in the oxidant gas discharge flow path, it is possible to promote the defrosting.

  The invention according to claim 8 is characterized in that the discharge flow path de-icing means is an oxidizing gas amount increasing means for increasing the amount of oxidizing gas supplied to the fuel cell.

  According to the eighth aspect of the present invention, even if a clogging phenomenon due to freezing occurs in the oxidant gas discharge flow path, by increasing the amount of oxidant gas (off-gas amount) discharged from the fuel cell, the ice The force to push out the outside increases. Further, since the oxidant gas (air) discharged from the oxidant gas supply means (air compressor) is compressed by the increase, the oxidant gas temperature (air temperature) also rises. Therefore, it is possible to promote ice melting.

  The invention according to claim 9 includes: a heat exchanger detour determination unit that determines whether or not the heat exchanger can be detoured; and a power generation amount increase unit that increases a power generation amount of the fuel cell. If the exchanger cannot be bypassed, the power generation amount of the fuel cell is increased.

  According to the ninth aspect of the present invention, since the clogged state in the oxidant gas discharge flow path due to freezing can be solved by increasing the power generation amount of the fuel cell, even if the mechanism detouring the heat exchanger is broken, the oxidation It is possible to prevent the fuel cell from continuing power generation due to the blocking of the agent gas discharge flow path.

  The invention according to claim 10 is a heat exchanger detourable determination means for determining whether the heat exchanger can be detoured, an oxidant gas amount increasing means for increasing the amount of oxidant gas supplied to the fuel cell, When the heat exchanger cannot be bypassed, the amount of oxidant gas supplied to the fuel cell is increased.

  According to the invention according to claim 10, since the blockage in the oxidant gas discharge flow path due to freezing can be solved by increasing the amount of oxidant gas in the fuel cell, even if the mechanism for bypassing the heat exchanger has failed, It becomes possible to prevent the continuation of power generation of the fuel cell due to the blockage of the oxidant gas discharge channel.

  The invention according to claim 11 is characterized in that when the heat generation state of the fuel cell is greater than or equal to a predetermined value, the control by the discharge channel deicing means is not performed. In addition, the heat generation state of the fuel cell means a state in which the allowable temperature of the fuel cell is exceeded when the discharge channel deicing means is performed when the fuel cell is above the predetermined value.

  According to the invention of claim 11, since the temperature can be increased so as not to exceed the allowable temperature of the fuel cell, the deterioration of the membrane (for example, the membrane electrode assembly) due to overheating of the fuel cell is prevented. Is possible. It is also possible to prevent heat damage to auxiliary equipment such as a humidifier that humidifies the oxidant gas supplied to the fuel cell.

  The invention according to claim 12 is characterized in that idling stop is prohibited when control by the discharge flow path de-icing means is performed. Note that idling stop means stopping the power generation in the fuel cell by stopping the oxidant gas supply means.

  According to the twelfth aspect of the present invention, since idling stop is prohibited, it is possible to prevent the temperature of the oxidant gas discharge flow path from decreasing and freezing from proceeding at idling stop.

  According to a thirteenth aspect of the present invention, when the outside air temperature is equal to or higher than a predetermined value, control by the discharge flow path deicing means is not performed.

  By the way, when the outside air temperature is equal to or higher than the predetermined temperature, the possibility of freezing in the oxidant gas discharge flow path is low, and there is a high possibility that an auxiliary machine such as a pressure sensor or a back pressure valve is out of order. Thus, according to the thirteenth aspect of the invention, when the outside air temperature is equal to or higher than a predetermined value, the control by the discharge channel deicing means is not performed, so that it is possible to prevent deterioration of the membrane due to overheating of the fuel cell. . That is, when the outside air temperature is equal to or higher than a predetermined value, valve failure determination and sensor failure determination are executed instead of control by the discharge flow path deicing means.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which can prevent the freezing of the discharge path | route after a normal driving | operation start can be provided.

(First embodiment)
FIG. 1 is an overall configuration diagram of the fuel cell system according to the first embodiment, FIG. 2 is a flowchart showing the deicing control in the fuel cell system according to the first embodiment, and FIG. 3 is a relationship between the opening of the back pressure valve and the pressure command value. FIG. 4 is a graph showing a change in convergence temperature of each part before and after the countermeasure. In the following, an automobile equipped with a fuel cell system will be described as an example. However, the present invention is not limited to this and may be applied to a ship, an aircraft, a stationary household power source, and the like.

  As shown in FIG. 1, the fuel cell system 1A according to the first embodiment includes a fuel cell FC, an anode system 20, a cathode system 30, a dilution system 40, an exhaust system 50, a control system 70, and the like.

  The fuel cell FC includes a membrane electrode structure in which an electrolyte membrane 2 made of a solid polymer having proton conductivity is sandwiched between an anode (hydrogen electrode) 3 containing a catalyst and a cathode (air electrode) 4 containing a catalyst. (MEA; MEMBRANE ELECTRODE ASSEMBLY), and a structure in which a plurality of unit cells (single cells) each including a membrane electrode structure sandwiched between a pair of conductive separators 5 and 6 are stacked in the thickness direction. Yes. In addition, the electrolyte membrane 2 is a membrane having characteristics that can exhibit performance when appropriately humidified. The fuel cell FC has an anode channel 5a through which hydrogen flows through the separator 5, a cathode channel 6a through which air flows through the separator 6, and a channel (not shown) through which a cooling medium flows. Is formed. In FIG. 1, for convenience of explanation, one single cell is schematically illustrated.

  The anode system 20 supplies hydrogen as fuel gas to the anode 3 of the fuel cell FC and discharges hydrogen from the anode 3. The hydrogen tank 21, ejector 22, purge valve 23, and pipes 24 a and 24 b are discharged from the anode 3. 24c, 24d, etc.

  The hydrogen tank 21 is a container filled with high-purity hydrogen gas at a high pressure, and includes an electromagnetically operated shut-off valve (not shown).

  The ejector 22 is a kind of vacuum pump for circulating unreacted hydrogen discharged from the anode 3 side of the fuel cell FC back to the anode 3 of the fuel cell FC. Further, the ejector 22 is connected to the hydrogen tank 21 via a pipe 24a, and is connected to the inlet on the anode 3 side of the fuel cell FC via a pipe 24b. The ejector 22 is connected to a pipe 24d branched from a pipe 24c connected to the outlet of the fuel cell FC on the anode 3 side. Hydrogen is circulated through these pipes 24b to 24d.

  The purge valve 23 is composed of, for example, an electromagnetically operated shut-off valve (ON / OFF valve), and has a function of opening it appropriately during operation and discharging impurities accumulated in the anode system 20 out of the system. Yes. The impurities are nitrogen contained in the air that has permeated from the cathode 4 to the anode 3 through the electrolyte membrane 2.

  Although not shown, the anode system 20 is provided with a regulator or the like for depressurizing high-pressure hydrogen from the hydrogen tank 21.

  The cathode system 30 supplies air (oxygen) as an oxidant gas to the cathode 4 of the fuel cell FC and discharges air and the like from the cathode 4. An air compressor (oxidant gas supply means) 31. , A cooler (heat exchanger) 32, a switching valve 33, a bypass pipe 34, a humidifier 35, a back pressure valve 36, cathode supply pipes 37a to 37d, cathode discharge pipes 38a and 38b, and the like.

  The air compressor 31 is constituted by a supercharger or the like driven by a motor, takes in air outside the vehicle (outside air), compresses it, and supplies it to the cathode 4 of the fuel cell FC.

  The cooler 32 is a so-called intercooler (I / C), and has a function of cooling the air that has been compressed by the air compressor 31 to a high temperature. The cooler 32 is connected to the air compressor 31 via the cathode supply pipe 37a. The cooler 32 may be air-cooled or water-cooled.

  The switching valve 33 is provided downstream of the cooler 32, is controlled to open and close by a control unit 71A described later, and is connected to the cooler 32 via a cathode supply pipe 37b.

  The bypass pipe 34 is branched from the cathode supply pipe 37 a, bypasses the cooler 32 and the switching valve 33, and merges with the cathode supply pipe 37 c connected downstream of the switching valve 33. It is connected. The bypass pipe 34 is provided with an orifice (not shown). When the switching valve 33 is opened, almost no air flows on the bypass pipe 34 side, and air flows on the cooler 32 side. It has become.

  In the present embodiment, the discharge flow path deicing means is configured by the switching valve 33, the bypass pipe 34, and the control unit 71A described later.

  The humidifier 35 includes, for example, a hollow fiber membrane module in which a plurality of water permeable membranes are bundled and accommodated in a case, and air from the air compressor 31 is circulated on one side of the inside and outside of the hollow fiber membrane, The cathode off gas (wet air, generated water) discharged from the cathode 4 of the fuel cell FC is circulated to the other side so that the air supplied from the air compressor 31 to the fuel cell FC is humidified. That is, in the humidifier 35, the inlet through which air before being humidified is introduced is connected to the cathode supply pipe 37c, and the outlet from which the air after being humidified is discharged is the inlet of the cathode 4 and the cathode of the fuel cell FC. The back pressure valve is connected via a supply pipe 37d, and an inlet through which the cathode off gas is introduced is connected to the outlet of the cathode 4 of the fuel cell FC via the cathode discharge pipe 38a, and an outlet from which the cathode off gas is discharged is described later. 36 and a cathode discharge pipe 38b.

  The back pressure valve 36 is constituted by a butterfly valve, for example, and has a function of appropriately adjusting the pressure of air supplied to the cathode 4 of the fuel cell FC. Further, the opening degree of the back pressure valve 36 is determined based on a pressure command value determined by the control unit 71A described later (see FIG. 3).

  The dilution system 40 has a function of diluting hydrogen discharged from the anode 3 of the fuel cell FC, and includes a diluter 41, pipes 42a and 42b, and the like.

  The diluter 41 is connected to a pipe 42a connected to the purge valve 23 and a pipe 42b connected to the back pressure valve 36. In the diluter 41, hydrogen discharged from the anode 3 of the fuel cell FC, A cathode off gas (such as air or water) discharged from the cathode 4 of the fuel cell FC is mixed and diluted to be discharged. When the hydrogen discharged from the fuel cell FC passes through the diluter 41, the hydrogen diluted to a hydrogen concentration below a specified level is discharged outside the vehicle (in the atmosphere).

  The exhaust system 50 includes a silencer 51, a tail pipe 52, a pipe 53, and the like.

  The silencer 51 has a function of reducing exhaust noise, and includes, for example, a cylindrical case that is divided into a plurality of interiors and provided with a sound absorbing material. The tail pipe 52 is a pipe connected to one end on the downstream side of the silencer 51, and is configured such that one end on the downstream side communicates with the outside of the vehicle (in the atmosphere). The pipe 53 is configured to connect the silencer 51 and the diluter 41.

  Note that the cathode discharge pipe 38a, the humidifying channel 35a, the cathode discharge pipe 38b, the pipe 42b, the diluter 41, the pipe 53, the silencer 51, and the tail after the outlet of the cathode 4 of the fuel cell FC. The pipe 52 constitutes the oxidant gas discharge flow path R (see FIG. 1) in the present embodiment. Moreover, the gas flow path in this embodiment is comprised by the cathode supply piping 37a-37d.

  The control system 70 includes a control unit 71A, a pressure sensor 72, a throttle opening sensor 73, a current sensor 74, an outside air temperature sensor 75, and the like.

  The control unit 71A includes a CPU (Central Processing Unit), a memory, an input / output interface, and various electric / electronic circuits, and includes a fuel cell warm-up completion determination unit, a discharge channel state determination unit, and a discharge channel deicing unit. Means. The control unit 71A is electrically connected to the purge valve 23, the air compressor 31, the switching valve 33, the back pressure valve 36, the pressure sensor 72, the throttle opening sensor 73, the current sensor 74, and the outside air temperature sensor 75, and the purge valve 23, the opening / closing of the switching valve 33, the rotation speed of the air compressor 31, and the opening of the back pressure valve 36 are appropriately controlled, and each detected value from a pressure sensor 72, a throttle opening sensor 73, a current sensor 74, and an outside air temperature sensor 75 described later. To get.

  The pressure sensor 72 has a function of detecting the pressure of the cathode system 30 of the fuel cell FC, and is provided, for example, in a pipe 38a near the outlet of the cathode 4 of the fuel cell FC. Note that the present invention is not limited to the vicinity of the outlet of the cathode 4 as long as the pressure of the cathode 3 of the fuel cell FC can be detected.

  The throttle opening sensor 73 is a sensor that detects the amount of depression of the accelerator pedal. For example, by depressing an accelerator pedal (not shown) during acceleration, the opening degree of the back pressure valve 36 is reduced according to the depression amount, or the rotational speed of the motor of the air compressor 31 is increased, and the cathode system 30 The pressure of is increased. That is, the pressure command value is appropriately set according to the depression amount of the accelerator pedal, the opening degree of the back pressure valve 36 is appropriately adjusted based on the pressure command value at that time, and the rotation speed of the air compressor 31 is appropriately adjusted. The

  The current sensor 74 is a sensor that detects a current value taken out from the fuel cell FC to the load 80 (see FIG. 1). The load 80 is an auxiliary machine such as a power storage device such as a travel motor or a battery, an air compressor 31, a purge valve 23, a switching valve 33, and a back pressure valve 36, for example. Note that the extraction of current from the fuel cell FC to the load 80 is controlled by a voltage control device (not shown).

  The outside air temperature sensor 75 (outside air temperature detecting means) is a sensor that detects the temperature outside the fuel cell system 1A (vehicle).

  Next, discharge channel deicing control in the fuel cell system 1A of the first embodiment will be described with reference to FIGS. 2 to 4 (refer to FIG. 1 as appropriate). 2 is described on the assumption that the fuel cell FC is started under a low temperature environment in which the fuel cell FC is warmed up.

  First, when an ignition switch (not shown) of the fuel cell vehicle (vehicle) is switched from OFF to ON, the control unit 71A opens a shut-off valve (not shown) provided in the hydrogen tank 21, and the hydrogen tank 21 supplies hydrogen to the anode 3 of the fuel cell FC, starts driving the air compressor 31, and supplies the air cooled by the cooler 32 and humidified by the humidifier 35 to the cathode 4 of the fuel cell FC. To control. Thereby, at the time of power generation, electrons are separated from hydrogen by the action of the catalyst at the anode 3, the electrons move to the cathode 4 through the load 80, and hydrogen ions permeate the electrolyte membrane 2 and move to the cathode 4. Further, in the cathode 4, water is generated by the reaction of the electrons that have moved from the anode 3 to the cathode 4 through the load 80, the hydrogen ions that have passed through the electrolyte membrane 2, and oxygen in the air by the action of the catalyst. .

  As shown in FIG. 2, in step S100, the control unit 71A determines whether or not the warm-up is completed. The warm-up is a process executed when the fuel cell system 1A is used in a low temperature environment (below freezing point). For example, air is supplied to the fuel cell FC at a higher flow rate and pressure than in normal operation. This is a process performed by generating power at a high output of the fuel cell FC. Further, as a condition for determining the completion of warm-up, it can be determined that the warm-up is completed when the temperature of the fuel cell FC exceeds a predetermined temperature (for example, 30 ° C.). In addition, this step S100 corresponds to the processing performed by the fuel cell warm-up completion determination unit in the present embodiment. In step S100, when controller 71A determines that warm-up has not been completed (No), it repeats step S100, and when it is determined that warm-up has been completed (Yes), normal power generation (steady state) The operation proceeds to step S110. The means for warming up the fuel cell FC is not limited to the above-described means, and a heater such as a catalytic combustion type or an electric type is used to heat the refrigerant circulating in the fuel cell FC and warm it up. May be.

  During normal operation, for example, the control unit 71A appropriately adjusts the opening degree of the back pressure valve 36 based on the detection value obtained from the throttle opening degree sensor 73. Specifically, when the throttle opening increases due to an increase in the depression amount of the accelerator pedal, the opening of the back pressure valve 36 is controlled in the closing direction so that the cathode pressure of the cathode system 30 increases. In this case, the controller 71A determines a pressure command value based on the throttle opening, and sets the opening of the back pressure valve 36 based on the determined pressure command value based on the map shown in FIG.

  In step S110, the control unit 71A determines whether or not the freeze prevention control is being performed. In step S110, when the control unit 71A determines that the freeze prevention control is not being performed (No), the control unit 71A proceeds to step S120A and detects the pressure command value determined by the throttle opening and the pressure sensor 72. The pressure value is compared, that is, it is determined whether (detected pressure value−pressure command value) is a predetermined value 1 or more. That is, when the inside of the oxidant gas discharge channel R is closed due to freezing, the pressure of the cathode 4 of the fuel cell FC rises, so that the back pressure valve 36 is controlled by feedback control. In this way, it can be determined that the pressure value detected by the pressure sensor 72 is higher than the determined pressure command value. Note that the predetermined value 1 or more means, for example, a case where the detected pressure value becomes excessively high with respect to the pressure command value and may impair the power generation performance of the fuel cell FC, or the oxidant gas discharge flow path R (pipe or the like). ) Is set in consideration of the case where a problem occurs. Further, step S120A and step S190A described later correspond to the processing performed by the discharge flow path state determining means in the present embodiment.

  In step S120A, when the control unit 71A determines that (detected pressure value−pressure command value) is equal to or greater than the predetermined value 1 (Yes), the control unit 71A proceeds to step S130 and detects the outside air temperature detected by the outside air temperature sensor 75. It is determined whether or not is higher than a predetermined temperature. The predetermined temperature is set in order to distinguish between failure of the pressure sensor 72 and freezing and can be set to 10 ° C., for example. By setting to such a temperature, if the temperature is a temperature at which freezing does not occur but the predetermined value is 1 or more, a failure of the pressure sensor 72, clogging of dust in the oxidant gas discharge channel R, etc. It can be judged that. Therefore, in step S130, when the control unit 71A determines that the outside air temperature is equal to or higher than the predetermined temperature (Yes), the control unit 71 proceeds to step S140, and determines that an auxiliary machine such as the pressure sensor 72 has failed.

  Then, the process proceeds to step S150, and the control unit 71A turns on a warning lamp (not shown) provided, for example, in the passenger compartment of the fuel cell vehicle. In addition, it is not limited to a warning lamp, A warning sound etc. may be sufficient.

  On the other hand, when the controller 71A determines in step S130 that the outside air temperature is not equal to or higher than the predetermined temperature (No), the controller 71A determines that there is no auxiliary machine failure, proceeds to step S160, and is obtained from the current sensor 74. It is determined whether or not the detected value (FC current) is equal to or greater than a predetermined current (discharge channel deicing control stop means). That is, step S160 is processing for detecting the heat generation state of the fuel cell FC. If the current value taken from the fuel cell FC to the load 80 is equal to or greater than a predetermined current, the heat generation state of the fuel cell FC is high, and the fuel It is determined that the battery FC is in a high temperature state. The predetermined current is set to a value that does not cause deterioration of the membrane electrode assembly due to overheating of the fuel cell FC when the air from the air compressor 31 is supplied to the fuel cell FC by bypassing the cooler 32. .

  The FC current is used as a means for determining the heat generation state of the fuel cell FC. However, the present invention is not limited to this, and the flow rate of air supplied to the fuel cell FC (air flow rate) The determination may be made based on the pressure (air pressure). If the air flow rate (air pressure) is equal to or higher than the predetermined flow rate (predetermined pressure), it can be determined that the fuel cell FC is in a high temperature state.

  In step S160, when the control unit 71A determines that the FC current is equal to or greater than the predetermined current (Yes), the control unit 71A proceeds to step S170 and performs control so that the I / C bypass is not performed. The I / C bypass means that the switching valve 33 is closed and the air from the air compressor 31 is supplied to the fuel cell FC through the bypass pipe 34 that bypasses the cooler 32. That is, when the I / C bypass is performed when the fuel cell FC is in a high temperature state, high-temperature air is supplied from the air compressor 31, and the fuel cell FC is further in a high temperature state and the membrane deteriorates. In order to prevent this, control is performed so that air from the air compressor 31 flows to the cooler 32 in a state where the switching valve 33 is opened without performing the I / C bypass.

  In step S170, control unit 71A prohibits idling stop of the fuel cell vehicle. The idling stop is a control that is performed in order to effectively use hydrogen (fuel gas), and is a control that stops power generation by stopping the air compressor 31 and continues operation using the power of the power storage device. is there. When the idling stop condition is satisfied, the idling stop is executed. The idling stop condition is, for example, that a fuel cell vehicle brake pedal (BKSW-ON, not shown) is depressed, the fuel cell vehicle is stopped (vehicle speed VS = 0), and the accelerator pedal is OFF (throttle opening = 0).

  In step S170, when idling stop is performed (air compressor 31 is stopped), warm cathode off-gas does not flow from the fuel cell FC, so that the idling stop is prohibited and freezing of the oxidant gas discharge channel R proceeds. Can be prevented.

  The idling stop condition is not limited to the above case, and may be when the vehicle is traveling in a cruise mode on a highway or the like. In this case, the air compressor 31 is stopped, the power generation in the fuel cell FC is stopped, and the vehicle can be run with electric power from only the power storage device (not shown).

  In step S160, when the control unit 71A determines that the FC current is not equal to or greater than the predetermined current (No), the control unit 71 proceeds to step S180 and performs control so as to perform I / C bypass. This step S180 corresponds to the processing performed by the discharge channel deicing means in the present embodiment. In this case, since the fuel cell FC is not in a high temperature state, control is performed so that air from the air compressor 31 flows into the bypass pipe 34 in a state where the switching valve 33 is closed. As a result, the temperature of the cathode off-gas discharged from the fuel cell FC becomes high, and the de-icing control in the oxidant gas discharge channel R is promoted.

  In step S180, the control unit 71A performs control so as to prohibit idling stop when the I / C bypass is performed (control by the discharge flow path deicing means). Also in this case, as described above, when the idling stop is performed (the air compressor 31 is stopped), the warm cathode off-gas does not flow from the fuel cell FC. Therefore, the oxidant gas discharge flow path R is prohibited by prohibiting the idling stop. It is possible to prevent the freezing of the battery from proceeding.

  On the other hand, in step S120A, when control unit 71A determines that (detected pressure value−pressure command value) is not equal to or greater than predetermined value 1 (No), control unit 71A proceeds to step S200 and does not perform I / C bypass. Control. That is, when (the detected pressure value−the pressure command value) is not equal to or greater than the predetermined value 1, the oxidant gas discharge flow path R is not in a closed state, so that the I / C bypass is not performed. In step S200, control unit 71A does not perform the I / C bypass and determines to allow idling stop. This is because the oxidant gas discharge flow path R is not in a closed state, so that even if idling stop is executed (even if the air compressor 31 is stopped), problems such as piping of the fuel cell system 1A are not caused. It is.

  If the controller 71A determines in step S110 that the ice-melting control (I / C bypass) is being performed, the process proceeds to step S190A, where (detected pressure value-pressure command value) is a predetermined value 2. It is determined whether or not: The predetermined value 2 is set to a value lower than the predetermined value 1, and the difference between the pressure command value and the detected pressure value does not deteriorate the power generation performance, and causes problems such as piping of the fuel cell system 1A. Set to a value that never happens. Thus, by controlling the predetermined value 1 and the predetermined value 2 so as to have a width, a so-called hunting phenomenon can be prevented. Note that the hunting phenomenon in the present embodiment means that the determination that the oxidant gas discharge channel R is in a closed state and the determination that it is not in a closed state are frequently switched.

  In step S190A, when the control unit 71A determines that (the detected pressure value−the pressure command value) is equal to or less than the predetermined value 2 (Yes), the control unit 71A determines that the oxidant gas discharge flow path R is not closed. Then, the process proceeds to step S200, and control is performed so as to allow idling stop without performing the I / C bypass control. In step S190A, if controller 71A determines that (detected pressure value−pressure command value) is not equal to or smaller than predetermined value 2 (No), it proceeds to step S130.

  Although not shown in the flow of FIG. 2, when the ignition switch is turned off, a shut-off valve (not shown) is closed and the supply of hydrogen from the hydrogen tank 21 to the fuel cell FC is stopped, The air compressor 31 is stopped and the supply of air to the fuel cell FC is stopped. Thereby, the power generation of the fuel cell FC is stopped, and the operation of the fuel cell system 1A is completed. In addition, when the anti-freezing control (I / C bypass, idling stop prohibition) is being performed and the ignition switch is turned off, the air compressor 31 is continuously driven, and the oxidant gas discharge flow path. The air compressor 31 may be stopped after the closed state of R is resolved.

  Further, deicing control will be described. Immediately after the completion of warm-up (S100, Yes), if the process of step S110 is the first time, the I / C bypass (freezing prevention control) is not performed (S110, No). In step S120A, it is determined whether (detected pressure value−pressure command value) is a predetermined value 1 or more. At that time, the oxidant gas discharge flow path R is not in the closed state, and (detected pressure value−pressure command value) is not equal to or greater than the predetermined value 1 (S120A, No), the I / C bypass is not performed, Allow idling stop (S200). As described above, when it is not determined that the oxidizing gas discharge flow path R is in the closed state, the processes of steps S100, S110, S120A, and S200 are repeated.

  When the oxidant gas discharge passage R is cooled by repeated idling stop or the like in a low temperature environment where the fuel cell system 1A reaches below freezing point, as shown by a solid line A (before countermeasures) in FIG. The oxidant gas discharge flow path R (for example, the tail pipe 52) becomes 0 ° C. or lower, and the oxidant gas discharge flow path R is closed. Accordingly, the detected pressure value becomes excessively high (becomes a predetermined value 1 or more) with respect to the pressure command value (S120A, Yes). At this time, when the auxiliary machine (pressure sensor 72) does not break down due to the outside air temperature (S130, No), and when the fuel cell FC is not in a high temperature state due to the current value (FC current) extracted from the fuel cell FC (S160) No), I / C bypass is performed, but idling stop is prohibited (S180). Note that by performing the I / C bypass, higher-temperature air is supplied to the fuel cell FC, so that the fuel cell FC is discharged as shown by a broken line B (after countermeasures) in FIG. The cathode off gas is discharged at a higher temperature. However, if idling stop is performed here, air is not supplied to the fuel cell FC, so idling stop is prohibited.

  On the other hand, when the fuel cell FC is in a high temperature state (S160, Yes), the I / C bypass control is stopped. In this case, idling stop is prohibited as in step S170. When the closed state of the oxidant gas discharge channel R continues as described above (S190A, No), the processing of steps S100, S110, S190A, S130, S160, S180 (or S170) in the flow of FIG. 2 is performed. Repeated. In step S170 (S180), if either the I / C bypass control or the idling stop prohibition control is performed, it is determined in step S110 that the freeze prevention control is being performed (S110, Yes).

  When the ice in the oxidant gas discharge flow path R is melted by the I / C bypass control or idling stop prohibition control and the closed state of the oxidant gas discharge flow path R is resolved, (detected pressure value−pressure) (Command value) becomes equal to or smaller than the predetermined value 2 (S190A, Yes), and if I / C bypass control is being performed, it is stopped and idling stop is permitted (S200).

  As described above, according to the first embodiment, even when the oxidant gas discharge channel R is closed due to freezing of the generated water after the warm-up is completed in a low temperature environment, the oxidant gas discharge channel R is blocked. Since the de-icing control can be performed based on the state, it is possible to prevent the power generation performance from being deteriorated due to freezing inside the oxidant gas discharge flow path R, and problems with piping and the like.

  In addition, according to the first embodiment, since the pressure command value and the detected pressure value can be compared to determine whether or not the oxidant gas discharge flow path R is in a closed state, a special for detecting the closed state is provided. Even if a simple device is not used, it is possible to estimate the closed state of the oxidant gas discharge flow path R simply by providing the pressure sensor 72.

  In addition, according to the first embodiment, since the air bypassing the cooler 32 (heat exchanger) is supplied to the fuel cell FC, higher temperature air can be supplied to the fuel cell FC. For this reason, the temperature of the cathode off-gas discharged from the fuel cell FC can be further increased, so that the generated water discharged from the fuel cell FC falls outside the fuel cell system 1A before it falls to the freezing temperature (for example, 0 ° C.). It can be discharged (outside the vehicle) (see broken line B in FIG. 4).

  Further, according to the first embodiment, since the fuel cell FC does not exceed the allowable temperature (S160), it is possible to prevent deterioration of the membrane (membrane electrode assembly) due to overheating of the fuel cell FC. become. Further, it is possible to prevent heat damage to the humidifier 35 by estimating that the allowable temperature of the humidifier 35 is not exceeded by the allowable temperature of the fuel cell FC.

(Second Embodiment)
FIG. 5 is an overall configuration diagram of the fuel cell system according to the second embodiment, FIG. 6 is a flowchart showing the deicing control in the fuel cell system according to the second embodiment, and FIG. 7 shows the relationship between the output of the air compressor and the flow rate command value. It is a map to show. The second embodiment differs from the first embodiment in that a control unit 71B and a flow rate sensor 76 are used instead of the control unit 71A and the pressure sensor 72. Only the different steps will be described below.

  As shown in FIG. 6, in step S120B, the control unit 71B determines whether (flow rate command value−detected flow rate value) is a predetermined value 3 or more. When the determination is made using the flow rate sensor 76 instead of the pressure sensor 72, the flow rate decreases when the oxidant gas discharge flow path R is closed, so that the detected flow rate value becomes lower than the flow rate command value. . The predetermined value 3 or more means, for example, a case where the detected flow rate value becomes excessively low with respect to the flow rate command value and may impair the power generation performance of the fuel cell FC, or the oxidant gas discharge flow path R (pipe or the like). ) Is set in consideration of the case where a problem occurs. Further, the control unit 71B determines a flow rate command value based on the throttle opening, and sets the rotation speed of the motor of the air compressor 31 based on the determined flow rate command value based on a map shown in FIG. Note that step S120B and S190B described later correspond to the processing performed by the discharge flow path state determining means in the present embodiment.

  In step S120B, when (flow rate command value−detected flow rate value) is equal to or greater than the predetermined value 3 (Yes), the control unit 71B determines that the oxidant gas discharge flow path R is in a closed state, and step S130. If (flow rate command value−detected flow rate value) is not equal to or greater than the predetermined value 3 (No), it is determined that the oxidant gas discharge flow path R is not in a closed state, and the flow proceeds to step S200.

  In step S190B, the control unit 71B determines whether (flow rate command value−detected flow rate value) is equal to or less than a predetermined value 4. The predetermined value 4 is set to a value smaller than the predetermined value 3. In this way, hunting can be prevented by controlling the predetermined value 3 and the predetermined value 4 with a width. In step S190B, when (flow rate command value−detected flow rate value) is equal to or less than the predetermined value 4 (Yes), the control unit 71B determines that the oxidant gas discharge flow path R is not in the closed state, and step S200. If (flow rate command value−detected flow rate value) is not equal to or less than the predetermined value 4 (No), it is determined that the oxidant gas discharge flow path R is in a closed state, and the flow proceeds to step S130.

  As described above, according to the second embodiment, the same effect as that of the first embodiment can be obtained. That is, it is possible to prevent a decrease in power generation performance due to freezing inside the oxidant gas discharge flow path R and problems with piping and the like. Further, it is possible to estimate the closed state of the oxidant gas discharge flow path R simply by providing the flow rate sensor 76 without using a special device for detecting the closed state. Further, since air bypassing the cooler 32 (heat exchanger) is supplied to the fuel cell FC, higher temperature air can be supplied to the fuel cell FC, and the temperature of the cathode off-gas discharged from the fuel cell FC can be reduced. The generated water discharged from the fuel cell FC can be discharged to the outside of the fuel cell system 1A (outside the vehicle) before it drops to the freezing temperature (for example, 0 ° C.) (broken line in FIG. 4). B). In addition, since the fuel cell FC does not exceed the allowable temperature (S160), it becomes possible to prevent the deterioration of the membrane electrode assembly due to overheating of the fuel cell FC. Further, it is possible to prevent heat damage to the humidifier 35 by estimating that the allowable temperature of the humidifier 35 is not exceeded by the allowable temperature of the fuel cell FC.

  The present invention is not limited to the above-described embodiments. In the first embodiment, the configuration of controlling the back pressure valve 36 based on the pressure command value is replaced with the configuration of the air compressor 31 based on the pressure command value. The rotational speed of the motor may be controlled. In this case, when the inside of the oxidant gas discharge flow path R freezes and becomes closed, the pressure of the cathode 4 of the fuel cell FC increases more than usual, so that the rotation speed of the air compressor 31 is controlled by feedback control. Is done. That is, the closed state may be determined by the detected pressure value being excessively higher than the pressure command value (being a predetermined value or more).

  Further, as the discharge channel state determination means, the closed state of the oxidant gas discharge channel R may be determined based on the feedback of the back pressure valve 36 in step S120A (S120B). That is, when the feedback value (opening in the opening direction) with respect to the opening command value of the back pressure valve 36 becomes equal to or greater than a predetermined value, it can be determined that the oxidant gas discharge flow path R is in a closed state. That is, the feedback of the back pressure valve 36 means that when the oxidant gas discharge channel R is frozen and closed, the pressure in the fuel cell FC rises above a predetermined value. It is a control that adjusts the pressure by opening the degree further. In step S190A (S190B), it is determined whether or not the feedback value with respect to the opening command value of the back pressure valve 36 has become less than a predetermined value (the predetermined value has a width to prevent hunting).

  Further, as the discharge flow path state determining means (S120A, S120B), the closed state of the oxidant gas discharge flow path R may be determined based on the feedback of the air compressor 31. That is, when the feedback with respect to the rotation speed command value (rotation speed command value) of the motor of the air compressor 31 becomes equal to or greater than the predetermined threshold value, it can be determined that the oxidant gas discharge flow path R is closed. In other words, the feedback of the air compressor 31 means that the air flow rate decreases when the oxidant gas discharge flow path R freezes and closes. Therefore, the air flow rate is increased by increasing the rotational speed of the air compressor 31 by feedback. Control to adjust.

  In the above-described discharge flow path state determination means, the control is focused on the air flow rate, but may be controlled based on the pressure in the fuel cell FC. That is, when the feedback with respect to the rotation speed command value (rotation speed command value) of the motor of the air compressor 31 becomes equal to or less than the predetermined threshold value, it can be determined that the oxidant gas discharge flow path R is closed. In other words, the feedback of the air compressor 31 in this case means that the pressure in the fuel cell FC rises from a predetermined value when the oxidant gas discharge flow path R is frozen and closed. This is a control to adjust the pressure by lowering the rotation speed.

  Further, instead of the configuration in which the bypass pipe 34 and the switching valve 33 that bypass the cooler 32 are provided as the discharge channel deicing means, control for increasing the heat generation amount of the fuel cell FC may be performed. That is, this is a process for increasing the amount of electric power extracted from the fuel cell FC by increasing the amount of air supplied from the air compressor 31 and consuming a large amount of oxygen and hydrogen in the air. Note that the electric power taken out from the fuel cell FC is charged in a power storage device (not shown). By increasing the output of the fuel cell FC in this manner, the amount of heat generated by the fuel cell FC is increased, and the exhaust temperature of the cathode off gas discharged from the fuel cell FC is increased. Alternatively, the flow rate may be increased by increasing the amount of air supplied from the air compressor 31.

(Third embodiment)
FIG. 8 is an overall configuration diagram of the fuel cell system according to the third embodiment, and FIG. 9 is a flowchart showing the deicing control in the fuel cell system according to the third embodiment. Note that the third embodiment has a configuration in which an alternative control is added to the first embodiment when the I / C bypass control fails. The overall configuration diagram of the fuel cell system 1C shown in FIG. 8 differs from the first embodiment in that a control unit 71C is used instead of the control unit 71A, and a pressure sensor 77 and a VCU (Voltage Control Unit) 81 are added. Further, the switching valve 33 shown in FIG. 8 includes a butterfly valve whose opening degree can be adjusted. Further, the bypass pipe 34 is provided with an orifice (not shown) similar to that of the first embodiment and the second embodiment (the same applies to the fourth embodiment described later). The flow shown in FIG. 9 is different from the first embodiment in that steps S165 and S210 are added to the flow of FIG. Only different configurations and steps will be described below.

  As shown in FIG. 8, the pressure sensor 77 is provided at the inlet of the fuel cell FC on the cathode 4 side, and the detected value (pressure value) is acquired by the control unit 71C. The VCU 81 controls the generated current (electric power) extracted from the fuel cell FC based on the power generation command from the control unit 71C. Note that the control unit 71C in the third embodiment is configured to further include a heat exchanger detour determination unit and a power generation amount increase unit.

  As shown in FIG. 9, in step S160, when the control unit 71C determines that the detected value (FC current) obtained from the current sensor 74 is not equal to or greater than the predetermined current (No), the process proceeds to step S165, where I / I It is determined whether or not the C bypass mechanism is normal. Whether or not the I / C bypass mechanism is normal is determined by detecting the pressure on the inlet side of the cathode 4 of the fuel cell FC by the pressure sensor 77 based on the opening change of the switching valve 33 (butterfly valve). When the detected pressure value is equal to or lower than the predetermined value, it is determined that the I / C bypass mechanism has failed. Moreover, this step S165 is equivalent to the process which the heat exchanger detour possibility judgment means in this embodiment implements.

  In step S165, if the control unit 71C determines that the I / C bypass mechanism has failed (No), the control unit 71C proceeds to step S210, and performs alternative control of the I / C bypass control. That is, by increasing the power generation current (power generation amount) extracted from the fuel cell FC based on the power generation command from the control unit 71C to the VCU 81, the self-heat generation amount of the fuel cell FC itself is increased and discharged from the fuel cell FC. Increase the temperature of the cathode offgas. The generated current taken out from the fuel cell FC is charged in a power storage device (not shown) such as a battery. As a result, the blockage of the oxidant gas discharge flow path R can be eliminated, so that even if the I / C bypass mechanism fails, the fuel cell FC cannot continue power generation due to the blockage of the oxidant gas discharge flow path R. Can be prevented. Note that step S210 corresponds to the processing performed by the power generation amount increasing means in the present embodiment.

  In Step S210, control part 71C performs control which prohibits an idling stop. In step S165, if the control unit 71C determines that the I / C bypass mechanism is normal (Yes), the control unit 71C performs the process of step S180.

  In the third embodiment, the power generation amount increase in the power generation amount increase means in step S210 is increased as the pipe blockage amount (the amount of frozen ice) in the oxidant gas discharge channel R increases. However, it is limited to a value that is lower than the endurance temperature of the fuel cell FC and other auxiliary machines.

(Fourth embodiment)
FIG. 10 is an overall configuration diagram of the fuel cell system according to the fourth embodiment. In addition, 4th Embodiment is the structure which added the alternative control when I / C bypass control fails to 1st Embodiment similarly to 3rd Embodiment. The overall configuration diagram of the fuel cell system 1D shown in FIG. 8 differs from the first embodiment in that a control unit 71D is used instead of the control unit 71A, and a pressure sensor 77, a flow sensor 78, and a temperature sensor 79 are added. Further, the flowchart showing the deicing control in the fuel cell system 1D of the fourth embodiment is the same as that of the third embodiment (flow of FIG. 9) except that the air amount is increased as an alternative control of step S210. Only the different configuration and step S210 will be described below.

  As shown in FIG. 10, the flow rate sensor 78 is provided on the upstream side of the air compressor 31, and the flow rate value of air (oxidant gas) introduced from the outside of the fuel cell system 1C is acquired by the control unit 71D. . The temperature sensor 79 is provided on the upstream side of the air compressor 31, and the temperature of air (oxidant gas) introduced from the outside of the fuel cell system 1C is acquired by the control unit 71D. Note that the control unit 71D in the fourth embodiment is configured to further include a heat exchanger detour determination unit and an oxidant gas amount increase unit.

  As shown in FIG. 9, in step S165, when the control unit 71D determines that the I / C bypass mechanism has failed (No), the control unit 71D proceeds to step S210 and performs alternative control of I / C bypass control. carry out. That is, by increasing the amount of air (oxidant gas amount) supplied from the air compressor 31 to the fuel cell FC by the control unit 71D, the ice blocking the oxidant gas discharge channel R is removed from the fuel cell system 1D. Increase the force to push out. Moreover, since the air discharged from the air compressor 31 is further compressed by increasing the air amount, the air temperature also rises. As a result, the blockage of the oxidant gas discharge flow path R can be eliminated, so that even if the I / C bypass mechanism fails, the fuel cell FC cannot continue power generation due to the blockage of the oxidant gas discharge flow path R. Can be prevented. Note that step S210 corresponds to the processing performed by the oxidizing gas amount increasing means in the present embodiment.

  In the fourth embodiment, the air amount increase in the oxidant gas amount increase means in step S210 is increased as the pipe blockage amount (the amount of frozen ice) in the oxidant gas discharge channel R increases. However, it is limited to a value that is lower than the endurance temperature of the fuel cell FC and other auxiliary machines.

  In the third embodiment and the fourth embodiment, the closed state of the oxidant gas discharge flow path R is determined based on the feedback of the back pressure valve 36, as in the above (first embodiment, second embodiment). Alternatively, the closed state of the oxidant gas discharge passage R may be determined based on the feedback of the air compressor 31.

1 is an overall configuration diagram of a fuel cell system according to a first embodiment. It is a flowchart which shows the ice-melting control in the fuel cell system of 1st Embodiment. It is a map which shows the relationship between the opening degree of a back pressure valve, and a pressure command value. It is a graph which shows the change of each part convergence temperature before and behind a countermeasure. It is a whole block diagram of the fuel cell system of 2nd Embodiment. It is a flowchart which shows the ice-melting control in the fuel cell system of 2nd Embodiment. It is a map which shows the relationship between an air compressor rotational speed and a flow volume command value. It is a whole block diagram of the fuel cell system of 3rd Embodiment. It is a flowchart which shows the ice-melting control in the fuel cell system of 3rd Embodiment. It is a whole block diagram of the fuel cell system of 4th Embodiment.

Explanation of symbols

1A to 1D Fuel cell system 5a Anode flow path 6a Cathode flow path 31 Air compressor (oxidant gas supply means)
32 Cooler (heat exchanger)
33 Switching valve 34 Bypass piping 35 Humidifier 36 Back pressure valve 37a-37d Cathode supply piping 38, 38b Cathode discharge piping 41 Diluter 51 Silencer 52 Tail pipe 71A-71D Control unit 72 Pressure sensor 75 Outside air temperature sensor 76 Flow rate sensor R Oxidizing agent Gas discharge channel FC Fuel cell

Claims (13)

A fuel cell for generating electricity by supplying an oxidant gas to the cathode channel and a fuel gas to the anode channel;
An oxidant gas supply means for supplying an oxidant gas to the fuel cell;
An oxidant gas discharge passage through which the oxidant gas discharged from the fuel cell is circulated and discharged;
A fuel cell warm-up completion determination means for determining whether or not the warm-up of the fuel cell is completed,
A discharge channel state determining means for determining whether or not the oxidant gas discharge channel is in a closed state due to freezing;
A discharge flow path deicing means for resolving a blockage caused by freezing of the oxidant gas discharge flow path;
After the fuel cell warm-up completion determining unit determines that the fuel cell has been warmed up, the exhaust channel state determining unit determines that the oxidant gas discharge channel is in a closed state. In this case, the fuel cell system is characterized in that the discharge channel deicing means performs control to defrost the inside of the oxidant gas discharge channel.   The discharge flow path state determining means determines a blocking state of the oxidant gas discharge flow path based on a pressure command value of the cathode flow path and a pressure value detected by the cathode flow path. The fuel cell system according to claim 1.   The discharge flow path state determining means determines a blocking state of the oxidant gas discharge flow path based on a flow rate command value of the cathode flow path and a flow rate value detected by the cathode flow path. The fuel cell system according to claim 1.   2. The fuel cell system according to claim 1, wherein the discharge flow path state determination unit determines a closed state of the oxidant gas discharge flow path based on feedback with respect to a back pressure valve opening command value.   2. The fuel cell system according to claim 1, wherein the discharge flow path state determination unit determines a closed state of the oxidant gas discharge flow path based on feedback with respect to a rotation speed command value of an air compressor. A heat exchanger provided in a gas flow path between the oxidant gas supply means and the fuel cell, for cooling the oxidant gas supplied to the fuel cell;
6. The discharge channel de-icing unit supplies the oxidant gas from the oxidant gas supply unit to the fuel cell by bypassing the heat exchanger. The fuel cell system according to claim 1.   The fuel cell system according to any one of claims 1 to 5, wherein the discharge flow path de-icing unit is a power generation amount increasing unit that increases a power generation amount of the fuel cell.   6. The discharge channel deicing means is oxidant gas amount increasing means for increasing the amount of oxidant gas supplied to the fuel cell, according to any one of claims 1 to 5. Fuel cell system. A heat exchanger bypassable determination means for determining whether the heat exchanger can be bypassed;
Power generation amount increasing means for increasing the power generation amount of the fuel cell,
The fuel cell system according to claim 6, wherein when the heat exchanger cannot be bypassed, the power generation amount of the fuel cell is increased. A heat exchanger bypassable determination means for determining whether the heat exchanger can be bypassed;
Oxidant gas amount increasing means for increasing the amount of oxidant gas supplied to the fuel cell,
The fuel cell system according to claim 6, wherein when the heat exchanger cannot be bypassed, the amount of oxidant gas supplied to the fuel cell is increased.   11. The fuel cell system according to claim 1, wherein when the heat generation state of the fuel cell is equal to or greater than a predetermined value, control by the discharge flow path deicing means is not performed.   The fuel cell system according to any one of claims 1 to 11, wherein idling stop is prohibited when control by the discharge flow path deicing means is performed.   The fuel cell system according to any one of claims 1 to 12, wherein when the outside air temperature is equal to or higher than a predetermined value, control by the discharge flow path deicing means is not performed.

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