JP2006147177A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system capable of suitably discharging at start-up or stoppage of a fuel cell, even with a small resistance. <P>SOLUTION: The fuel cell system 1 is equipped with a fuel cell 2 generating power by reaction of reaction gas; an auxiliary circuit 50 with an auxiliary resistor 51, connected to the fuel cell 2; a control part 71 (a compensation judgment means) for judging whether the auxiliary circuit 50 is within a compensation condition; and a control part 71 (an auxiliary circuit control means) for controlling a switching operation of the auxiliary circuit 50 based on judgment of the control part 71. The control part 71 turns on the auxiliary circuit if the circuit 50 is within the compensation condition, and does not turns on if the circuit 50 is outside the compensation condition, at start-up or stoppage of the fuel cell 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system.

  2. Description of the Related Art In recent years, development of fuel cell stacks (sometimes referred to as fuel cells) in which a plurality of single cells are stacked has been actively developed as a power source for fuel cell vehicles. When a fuel cell generates electricity, water is generated mainly on the cathode (air electrode) side. Part of the generated water diffuses in the solid polymer electrolyte membrane (hereinafter referred to as electrolyte membrane) constituting the single cell and permeates to the anode (fuel electrode) side. In order to maintain the wet state of the electrolyte membrane, a method of supplying humidified oxidant gas (for example, humidified air) to the cathode side is generally employed.

  Thus, the water content of the gas flowing through the fuel cell is high due to water generated by power generation and humidification. Therefore, when the temperature of gas falls, the water contained in gas will condense. Therefore, when the fuel cell is used in the winter or in a cold region, if the fuel cell is exposed to below freezing after being stopped, the inside of the fuel cell may freeze.

  Therefore, in order to prevent such freezing, for example, when the fuel cell is stopped, non-humidified air (scavenging gas) is supplied to the fuel gas channel and the oxidant gas channel in the fuel cell, and the scavenging (fuel) A method of discharging water in the battery and purging air) is adopted.

  However, when the scavenging gas is supplied in this way, the fuel gas and the scavenging gas may be mixed in the fuel gas flow path of the fuel cell. Then, a portion in contact with the fuel gas and a portion in contact with the scavenging gas are formed on the anode side of one single cell membrane electrode assembly (hereinafter also referred to as MEA: Membrane Electrode Assembly). Coexist. As a result, for one MEA, a portion where the fuel gas exists on the anode side and an oxidant gas exists on the cathode side (hereinafter referred to as a first MEA portion), a scavenging gas on the anode side, and a portion where the oxidant gas exists on the cathode side (Hereinafter, the second MEA portion) coexists.

  In such a case, a small potential difference occurs in the first MEA portion, while a phenomenon that no potential difference occurs in the second MEA portion occurs. Then, a pseudo circuit may be formed in one MEA using the small potential difference generated in the first MEA part as a driving force, and a minute current may flow in the second MEA part.

  As described above, when a small amount of current flows in one MEA, the electrolyte membrane, the anode, the cathode, and the like of the second MEA portion deteriorate, and as a result, there is a problem that the life of the fuel cell is shortened.

  Therefore, conventionally, a fixed resistor is connected to the output terminal of the fuel cell stack separately from the external load, and the current generated when gas is mixed in the fuel gas flow path is passed through the fixed resistor to discharge (discharge). The technique to do is proposed (refer patent document 1).

JP-A-10-284104 (paragraph numbers 0010 to 0012, FIGS. 1 and 2)

  However, when the ignition switch (hereinafter referred to as IGSW), which is the start switch of the fuel cell, is linked to ON / OFF, the discharge at the start and the discharge at the stop are always executed. For example, the IGSW is continuously turned on. When turned off, the temperature of the fixed resistor rises and eventually breaks due to disconnection or the like. In order to prevent this failure of the fixed resistor, a method of increasing the capacity of the fixed resistor is conceivable. However, if the capacity of the fixed resistor is increased, the bulk and mass of the fixed resistor increase, so that it can be mounted on a fuel cell vehicle or the like. Is unsuitable.

  Therefore, an object of the present invention is to provide a fuel cell system that can be suitably discharged even when the fuel cell is started or stopped even with a small resistance.

  As means for solving the above-mentioned problems, the invention according to claim 1 is directed to a fuel cell that generates electric power by reaction of a reaction gas, an auxiliary circuit that has an auxiliary resistor and is connected to the fuel cell, and the auxiliary circuit has compensation conditions. Compensation determination means for determining whether or not it is within, and auxiliary circuit control means for controlling ON / OFF of the auxiliary circuit based on the determination of the compensation determination means, wherein the auxiliary circuit control means is the fuel cell In the fuel cell system, when the auxiliary circuit is in a compensation condition, the auxiliary circuit is turned on, and when the auxiliary circuit is out of the compensation condition, the auxiliary circuit is not turned on.

Here, the “auxiliary circuit having an auxiliary resistance” is connected to the output terminal of the fuel cell, and fuel gas (such as hydrogen) and scavenging gas (non-humidified air) are mixed in the fuel gas flow path of the fuel cell. For this purpose, this is a circuit for taking out the current generated in the single cell (MEA) of the fuel cell and discharging it out of the fuel cell.
Further, “when the fuel cell is activated” is when a switch (IGSW in the first embodiment described later) for activating the fuel cell is turned on.

According to such a fuel cell system, when the auxiliary circuit is within the compensation condition at the time of starting the fuel cell, the auxiliary circuit control means turns on the auxiliary circuit so that the current generated in the fuel cell is The fuel cell is discharged (discharged) by flowing through the inside, and deterioration of the fuel cell can be prevented. On the other hand, when the auxiliary circuit is outside the compensation condition, the auxiliary circuit control means does not turn on (turns off) the auxiliary circuit, so that no current flows through the auxiliary circuit, and the auxiliary circuit can be protected.
Therefore, even if the auxiliary resistor constituting the auxiliary circuit is small, the auxiliary resistor can be protected and appropriately discharged by appropriately setting the compensation condition.

  According to a second aspect of the present invention, there is provided a fuel cell for generating electric power by reaction of a reaction gas, an auxiliary circuit having an auxiliary resistor and connected to the fuel cell, and a compensation determining means for determining whether or not the auxiliary circuit is within compensation conditions. And auxiliary circuit control means for controlling ON / OFF of the auxiliary circuit based on the determination of the compensation determination means, and the auxiliary circuit control means is configured so that the auxiliary circuit is in a compensation condition when the fuel cell is stopped. The fuel cell system is characterized in that the auxiliary circuit is turned on when the auxiliary circuit is within, and the auxiliary circuit is not turned on when the auxiliary circuit is out of compensation conditions.

  Here, “when the fuel cell is stopped” is when the switch for starting the fuel cell (IGSW in the first embodiment described later) is turned OFF.

According to such a fuel cell system, when the auxiliary circuit is within the compensation condition when the fuel cell is stopped, the auxiliary circuit control means turns on the auxiliary circuit so that the current generated in the fuel cell is reduced. The fuel cell is discharged (discharged) by flowing through the inside, and deterioration of the fuel cell can be prevented. On the other hand, when the auxiliary circuit is outside the compensation condition, the auxiliary circuit control means does not turn on (turns off) the auxiliary circuit, so that no current flows through the auxiliary circuit, and the auxiliary circuit can be protected.
Therefore, even if the auxiliary resistor constituting the auxiliary circuit is small, the auxiliary resistor can be protected and suitably discharged by setting a predetermined compensation condition.

  The invention according to claim 3 further includes temperature detecting means for detecting the temperature of the auxiliary resistor, and the compensation determining means is configured such that the auxiliary circuit is out of compensation conditions when the temperature of the auxiliary resistor is higher than a predetermined temperature. 3. The fuel cell system according to claim 1, wherein the auxiliary circuit determines that the auxiliary circuit is within a compensation condition when it is determined that the auxiliary resistor is at a temperature equal to or lower than the predetermined temperature. 4. is there.

  According to such a fuel cell system, the compensation determining means determines that the auxiliary circuit is outside the compensation condition when the temperature of the auxiliary resistor is higher than the predetermined temperature, and when the temperature of the auxiliary resistor is equal to or lower than the predetermined temperature. It can be determined that the auxiliary circuit is within compensation conditions.

  The invention according to claim 4 further includes auxiliary circuit ON / OFF history storage means for recording the ON / OFF history of the auxiliary circuit, and the compensation determination means is based on the past ON / OFF history of the auxiliary circuit. 3. The fuel cell system according to claim 1, wherein it is determined whether or not the auxiliary circuit is within a compensation condition.

  According to such a fuel cell system, the compensation determination means estimates, for example, the current temperature of the auxiliary resistor based on the past ON / OFF history of the auxiliary circuit, and whether or not the auxiliary circuit is within the compensation condition. Can be determined.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is small resistance, the fuel cell system which can be discharged suitably at the time of starting or stopping of a fuel cell can be provided.

Embodiments of the present invention will be described below with reference to the drawings as appropriate.
In the description of each embodiment, the same constituent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

<< First Embodiment >>
The fuel cell system according to the first embodiment will be described with reference to FIGS. 1 to 5 as appropriate. In the drawings to be referred to, FIG. 1 is a configuration diagram of a fuel cell system according to a first embodiment. FIG. 2 is a flowchart showing control at the time of startup of the fuel cell system according to the first embodiment. FIG. 3 is a flowchart showing control at the time of stopping of the fuel cell system according to the first embodiment. FIG. 4 is a temperature chart and timing chart of the auxiliary resistance of the fuel cell system according to the first embodiment. FIG. 5 is a temperature chart and timing chart of the auxiliary resistance of the fuel cell system according to the first embodiment.

≪Configuration of fuel cell system≫
As shown in FIG. 1, the fuel cell system 1 according to the first embodiment is a system mounted on a fuel cell vehicle, and when the fuel cell vehicle is started / stopped (when the fuel cell 2 is started / stopped). In addition, this is a system that performs a charge by discharging the switch 52 appropriately.

  The fuel cell system 1 includes a fuel cell 2, an anode system that supplies and discharges hydrogen gas (fuel gas, reaction gas) to the anode side of the fuel cell 2, and humidified air (oxidant gas, Reactive gas) or scavenging gas (non-humidified air), a scavenging system for guiding the scavenging gas from the cathode system to the anode system during scavenging, a power consumption system connected to the output terminal of the fuel cell 2, An auxiliary circuit 50 connected to the power consumption system, a temperature sensor 61, an IGSW 62, and an ECU 70 (Electronic Control Unit, control device) for controlling them are mainly provided.

<Fuel cell>
The fuel cell 2 (fuel cell stack) is mainly configured by stacking a plurality of single cells each having both surfaces of the electrolyte membrane 3 sandwiched between an anode (fuel electrode) and a cathode (air electrode) via a separator. Has been. In the separator, a groove for supplying hydrogen gas (fuel gas) and humidified air (oxidant gas) to the entire surface of the electrolyte membrane 3, a through hole for supplying each single cell, and the like are formed in a complicated manner. These grooves and the like function as the fuel gas channel 4 and the oxidant gas channel 5. Hydrogen gas flows through the fuel gas flow path 4, and this flowing hydrogen gas is supplied to each anode. On the other hand, humidified air circulates in the oxidant gas flow path 5, and this circulated humidified air is supplied to each cathode.
When hydrogen gas is supplied to each anode and humidified air is supplied to each cathode, an electrochemical reaction occurs in each anode and each cathode, and a predetermined potential difference is generated in each single cell. This single cell is generally connected in series. Therefore, it is possible to take out large electric power from the fuel cell 2.

<Anode system>
The anode system is a system that is arranged on the anode side of the fuel cell 2 and that supplies and discharges hydrogen gas. The anode system mainly includes a hydrogen tank 11 that stores hydrogen gas and a shut-off valve 12.

Explaining the anode-side hydrogen gas supply side, the shutoff valve 12 is integrally attached to the outlet of the hydrogen tank 11. The shutoff valve 12 is connected to the fuel gas flow path 4 of the fuel cell 2 on the downstream side via the pipe 12a. The shut-off valve 12 is electrically connected to a control unit 71 of the ECU 70 to be described later, and the control unit 71 opens / closes the shut-off valve 12 as appropriate. Further, the pipe 12a is provided with a pressure reducing valve for depressurizing the fuel cell 2 to a predetermined degree, an ejector for circulating the anode off gas (both not shown), and the like.
Therefore, when the control unit 71 opens the shutoff valve 12, the hydrogen gas is decompressed to a predetermined level and supplied to the fuel gas flow path 4.

  Next, the hydrogen gas discharge side of the anode system will be described. The pipe 12b is connected to the fuel gas flow path 4, and the gas discharged from the anode side of the fuel cell 2 (anode off-gas during power generation, scavenging during scavenging) Gas) is discharged out of the system (in the atmosphere) through the pipe 12b. Further, the pipe 12b is branched at an intermediate position, and the branched portion is connected to the ejector. Therefore, when unreacted hydrogen gas is contained in the anode off gas, it is returned to the hydrogen supply side, and the hydrogen gas is circulated.

<Cathode system>
The cathode system is disposed on the cathode side of the fuel cell 2 and mainly supplies and discharges air (a scavenging gas that is humidified air during normal power generation and non-humidified air during scavenging), and is a pump 21 (compressor). It is mainly equipped with.

Explaining the cathode system air supply side, the pump 21 is connected to the oxidant gas flow path 5 of the fuel cell 2 on the downstream side via a pipe 21a. The pump 21 is electrically connected to a control unit 71 of the ECU 70 described later, and the control unit 71 controls the operation of the pump 21 as desired. A humidifier (not shown) is provided in the middle of the pipe 21a so that it is humidified during power generation and is not humidified during scavenging.
Explaining the air discharge side of the cathode system, the pipe 21b is connected to the oxidant gas flow path 5, and the gas discharged from the cathode side of the fuel cell 2 (cathode off-gas during power generation, scavenging gas during scavenging) The gas is discharged out of the system (in the atmosphere) via the pipe 21b.

<Scavenging system>
The scavenging system is a system that guides the scavenging gas (non-humidified air) from the pump 21 from the cathode system to the anode system when scavenging the fuel cell 2, and mainly includes a pipe 31 and an on-off valve 32.
Here, the “scavenging gas” is a gas having a predetermined pressure for extruding water or the like in the fuel cell 2 to the outside of the fuel cell 2 and cleaning the inside of the fuel cell 2, and is, for example, air or nitrogen. . “To scavenge” means to introduce the scavenging gas into the fuel gas flow path 4 and the oxidant gas flow path 5 of the fuel cell 2 to push out the water in the fuel cell 2 to the outside of the fuel cell 2.

One end of the pipe 31 is connected to the cathode pipe 21a, and the other end of the pipe 31 is connected to the anode pipe 12a. The on-off valve 32 is provided in the middle of the pipe 31 and can appropriately block the gas flow in the pipe 31. The on-off valve 32 is electrically connected to a control unit 71 of the ECU 70 described later, and the control unit 71 opens / closes the on-off valve 32 as appropriate.
Therefore, when scavenging the fuel cell 2, the on-off valve 32 is opened, the humidification by the humidifier is stopped, and the scavenging gas (non-humidified air) from the pump 21 is supplied to the oxidant gas flow path 5 via the pipe 21a. The fuel gas passage 4 can be supplied via the pipe 31 and the pipe 12a.
On the other hand, the open / close valve 32 is closed during normal power generation of the fuel cell 2.

<Power consumption system>
The power consumption system mainly includes an external load 41 such as a travel motor for driving a fuel cell vehicle, a main switch 42 (relay), an ammeter 43, and a voltmeter 44. The external load 41 is electrically connected to the output terminal of the fuel cell 2 via the main switch 42.

The ammeter 43 is disposed between the main switch 42 and the fuel cell 2 and on the anode side terminal (minus terminal) side of the fuel cell 2. Therefore, when the ammeter 43 does not detect a current during discharge (the main switch 42 is OFF and the switch 52 is ON), it can be determined that the auxiliary resistor 51 described later is broken (disconnected).
The ammeter 43 is electrically connected to a control unit 71 of the ECU 70 described later. Therefore, the control unit 71 detects the current value flowing through the external load 41 during normal power generation (the main switch 42 is ON and the switch 52 is OFF), and the current value flowing through the auxiliary resistor 51 during discharge. The failure of the auxiliary resistor 51 can be determined.

  The voltmeter 44 is arranged in parallel with the external load 41 between the output terminal of the fuel cell 2 and the main switch 42. The voltmeter 44 is electrically connected to a control unit 71 of the ECU 70 described later. Therefore, the control unit 71 determines the voltage across the terminals of the fuel cell 2 during normal power generation (the main switch 42 is ON and the switch 52 is OFF), and during discharge (the main switch 42 is OFF and the switch 52 is ON). The voltage of the auxiliary resistor 51 can be monitored.

<Auxiliary circuit>
The auxiliary circuit 50 is a circuit for taking out a minute current from the fuel cell 2 when hydrogen gas and scavenging gas are mixed in the fuel gas flow path 4, and is connected between the ammeter 43 and the main switch 42. The load 41 is connected in parallel. The auxiliary circuit 50 mainly includes an auxiliary resistor 51 and a switch 52 (relay).
More specifically, one side of the switch 52 is electrically connected to the wiring between the ammeter 43 and the main switch 42. The other side of the switch 52 is electrically connected to the wiring between the cathode side terminal (plus terminal) of the fuel cell 2 and the main switch 42 via the auxiliary resistor 51.
Further, the capacity of the auxiliary resistor 51 is determined based on the magnitude of the current at the time of discharging, but is very small (for example, about 200 W), and is very small and bulky.

<Temperature sensor, etc.>
The temperature sensor 61 (temperature detection means) is provided in the vicinity of the auxiliary resistor 51 and can detect the temperature of the auxiliary resistor 51 (hereinafter, auxiliary resistance temperature T1). The temperature sensor 61 is electrically connected to a control unit 71 of the ECU 70 described later, and the control unit 71 can monitor the auxiliary resistance temperature T1.
The IGSW 62 is a start switch for the fuel cell vehicle and the fuel cell system 1, and is provided around the driver's seat of the fuel cell vehicle. The IGSW 62 is electrically connected to a control unit 71 of the ECU 70 described later, and the control unit 71 can monitor ON / OFF of the IGSW 62.

<ECU>
The ECU 70 includes a CPU, ROM, RAM, various interfaces, electronic circuits, various storage media, and the like, and includes a control unit 71 (compensation determination unit, auxiliary circuit control unit), an auxiliary resistance data storage unit 72, a clock 73 is mainly provided.

[Control section-compensation judgment function]
The input side of the control unit 71 is electrically connected to the temperature sensor 61, and the control unit 71 can monitor the auxiliary resistance temperature T1. The control unit 71 compares the auxiliary resistance temperature T1 with the predetermined temperature T0 stored in the auxiliary resistance data storage unit 72 and determines whether the auxiliary circuit 50 is within the compensation condition (compensation). Judgment function).

  Further, the input side of the control unit 71 is connected to the IGSW 62 so that ON / OFF of the IGSW 62 can be monitored. In addition, the input side of the control unit 71 is connected to an ammeter 43 and a voltmeter 44 of a power consumption system.

[Control unit-auxiliary circuit control function]
The output side of the control unit 71 is electrically connected to the switch 52 of the auxiliary circuit 50, and the control unit 71 is configured to turn ON / OFF the switch 52 appropriately. That is, the control unit 71 has a function of controlling ON / OFF of the auxiliary circuit 50 (auxiliary circuit control function). Note that ON / OFF of the switch 52 corresponds to ON / OFF of the auxiliary circuit 50.
In addition, the output side of the control unit 71 is connected to the anode shutoff valve 12, the cathode pump 21, and the scavenging system on / off valve 32, and the control unit 71 can control these as desired. ing.

[Control Unit-Auxiliary Circuit ON Time Δt1 Measurement Function, Fuel Gas Flow State Determination Function]
The control unit 71 can measure the ON time of the auxiliary circuit 50 (hereinafter referred to as auxiliary circuit ON time Δt1) based on the time from the clock 73 (auxiliary circuit ON time Δt1 measurement function).
Further, the control unit 71 compares the auxiliary circuit ON time Δt1 with a predetermined time Δt0 stored in the auxiliary resistance data storage unit 72, which will be described later, and the fuel gas channel 4 is made of hydrogen gas when the fuel cell 2 is started. It has a function of determining whether or not the fuel cell 2 is satisfied when the fuel cell 2 is stopped (fuel gas channel state determination function).

[Auxiliary resistance data storage section]
The auxiliary resistance data storage unit 72 is electrically connected to the control unit 71, and the control unit 71 can be accessed as appropriate.
The auxiliary resistance data storage unit 72 stores a predetermined temperature T0. The predetermined temperature T0 is a preset temperature that is a reference for ON / OFF of the switch 52 of the auxiliary circuit 50. More specifically, the control unit 71 permits the switch 52 to be turned on when the auxiliary resistance temperature T1 is equal to or lower than the predetermined temperature T0, and does not allow the switch 52 to be turned on when the auxiliary resistance temperature T1 is higher than the predetermined temperature T0 ( OFF). In other words, if the switch 52 is turned on for the auxiliary resistor 51 having a temperature higher than the predetermined temperature T0, the auxiliary resistor 51 may be further heated to break down due to disconnection or the like, but the reference predetermined temperature T0 is set. By doing so, the failure of the auxiliary resistor 51 is prevented. Specifically, for example, when the capacity of the auxiliary resistor 51 is 200 W, the predetermined temperature T0 is set to 220 ° C.

The auxiliary resistance data storage unit 72 stores a predetermined time Δt0. The predetermined time Δt0 means that the supply of hydrogen gas is started when the fuel cell 2 is started, the supply of scavenging gas is started when the fuel cell 2 is stopped, and then the fuel gas passage 4 is made of hydrogen gas or scavenging gas. It is time to be satisfied. Therefore, the predetermined time Δt0 depends on the shape (length, width, etc.) of the fuel gas passage 4 of the fuel cell 2 and the supply pressure of the hydrogen gas / scavenging gas, and is obtained in advance by a preliminary experiment or the like. Specifically, the predetermined time ΔT0 is set to 4 seconds, for example.
Here, in the first embodiment, in order to simplify the description, after the hydrogen gas supply starts when the fuel cell 2 is started, the fuel gas passage 4 is filled with the hydrogen gas for a predetermined time Δt0 and when the fuel cell 2 is stopped. A case where the predetermined time Δt0 for filling the fuel gas flow path 4 with the scavenging gas after the start of the scavenging gas supply is the same will be described. However, it goes without saying that these times may be set separately.

[clock]
The clock 73 always keeps time, and this time is sent to the control unit 71.

≪Control flow of fuel cell system 1≫
Next, the control flow set in the fuel cell system 1 according to the first embodiment will be described with reference to the flowcharts shown in FIGS. 2 and 3 as appropriate.
Here, when the IGSW 62 is turned on, the ECU 70 proceeds with processing according to the control flow at the time of startup shown in FIG. Further, when the IGSW 62 is turned off, the processing proceeds according to the control flow at the time of stop shown in FIG. Further, when the IGSW 62 is turned off while the IGSW 62 is turned on and processing is performed according to the startup control flow shown in FIG. 2, the processing according to the startup control flow shown in FIG. The processing is switched to the control flow at the time of stop shown in FIG. On the contrary, when the IGSW 62 is turned on during the processing according to the control flow at the time of stop shown in FIG. 3, the processing is switched to the control flow at the time of startup shown in FIG.

<Control flow when the fuel cell 2 is started (when the IGSW 62 is ON)>
First, the control flow at the start-up of the fuel cell system 1 when the IGSW 62 is turned on will be described with reference to FIG.

  When the IGSW 62 is turned on, the “control flow at startup” shown in FIG. 2 starts. Here, a case where scavenging with scavenging gas is performed when the fuel cell system 1 is stopped last time and the fuel gas channel 4 and the oxidant gas channel 5 are filled with scavenging gas will be described.

[Auxiliary circuit compensation judgment]
In step S <b> 101 </ b> A, the control unit 71 performs compensation determination regarding whether or not the auxiliary circuit 50 is within the compensation condition. Specifically, the control unit 71 determines that “when the auxiliary resistance temperature T1 is equal to or lower than the predetermined temperature T0 (T1 ≦ T0), the auxiliary circuit 50 is within the compensation condition”, and “the auxiliary resistance temperature T1 is equal to the predetermined temperature. If it is higher than T0 (T1> T0), the auxiliary circuit 50 is out of compensation conditions ”.

  When the control unit 71 determines that “the auxiliary resistance temperature T1 is equal to or lower than the predetermined temperature T0 and the auxiliary circuit 50 is within the compensation condition” (S101A / Yes), the process proceeds to step S102. On the other hand, when the control unit 71 determines that “the auxiliary resistance temperature T1 is higher than the predetermined temperature T0 and the auxiliary circuit 50 is outside the compensation condition” (S101A / No), the process proceeds to step S109.

A route that proceeds in the order of steps S102, S103A, S104, S105A, and S106 corresponds to a route for performing discharge when the fuel cell 2 is started up (startup discharge execution route).
On the other hand, a route that proceeds in the order of steps S109, S110, and S111 corresponds to a route that does not perform discharge when the fuel cell 2 is activated (a discharge-non-execution route when activated). In the following, description will be given in the order of “startup discharge execution route” and “startup discharge non-execution route”.

[Discharge execution route at startup]
In step S102, the control unit 71 opens the shutoff valve 12. Thereby, hydrogen gas is supplied from the hydrogen tank 11 to the fuel gas flow path 4 of the fuel cell 2 via the pipe 12a (hydrogen gas supply start).

  In step S103A, the control unit 71 turns on the switch 52 of the auxiliary circuit 50 (turns on the auxiliary circuit 50 and starts discharge at startup). Even if hydrogen gas and scavenging gas are mixed in the fuel gas flow path 4 by turning on the switch 52 and a small potential difference is generated in each single cell constituting the fuel cell 2, a current having this potential difference as a driving force. However, not in a single cell but through the external auxiliary circuit 50, the battery is discharged at the time of startup. Thereby, deterioration of each single cell which comprises the fuel cell 2 can be prevented.

The controller 71 measures the auxiliary circuit ON time Δt1 (= ON time of the switch 52) based on the time from the clock 73, starting from the ON of the switch 52.
Although step S102 and step S103A are divided into separate steps for convenience of explanation, they are processed substantially simultaneously.
Further, the auxiliary circuit ON time Δt1 is initialized when switching to the control flow at the stop shown in FIG. 3 during the processing according to the control flow at the start shown in FIG. The same applies when switching from the control flow at the time of stopping (FIG. 3) to the control flow at the time of starting (FIG. 2).

  In step S104, the control unit 71 turns on the operation of the pump 21. The outside air is compressed to a predetermined level by turning on the pump 21, and the humidified air humidified by the humidifier is supplied to the oxidant gas flow path 5.

(Fuel gas flow path state judgment)
In step S105A, the control unit 71 determines whether or not the fuel gas passage 4 is filled with hydrogen gas. Specifically, the control unit 71 determines that “when the auxiliary circuit ON time Δt1 is longer than the predetermined time Δt0 (Δt1> Δt0), it is filled with hydrogen gas”, and “the auxiliary circuit ON time Δt1 is the predetermined time Δt0. In the case of the following (Δt1 ≦ Δt0), it is determined that it is not filled with hydrogen gas ”.

When the controller 71 determines that “the auxiliary circuit ON time Δt1 is longer than the predetermined time t0 and the fuel gas passage 4 is filled with hydrogen gas” (S105A / Yes), the process proceeds to step S106. .
On the other hand, when the control unit 71 determines that “the auxiliary circuit ON time Δt1 is equal to or shorter than the predetermined time and the fuel gas flow path 4 is not filled with hydrogen gas” (S105A / No), the control unit 71 returns to step S105A and returns to the auxiliary circuit. The determination in step S105A is repeated until the ON time Δt1 exceeds the predetermined time t0.

  In step S106, the control unit 71 turns off the switch 52 of the auxiliary circuit 50 (OFF of the auxiliary circuit 50). When the switch 52 is turned off, the discharge at startup is completed.

  In step S107, the control unit 71 turns on the main switch 42. Thereby, the fuel cell 2 and the external load 41 are electrically connected. Further, the control unit 71 checks the terminal voltage of the fuel cell 2 via the voltmeter 44.

In step S108, the power generation of the fuel cell 2 is started in response to the power demand of the external load 41.
And it progresses to an end and the process which concerns on the discharge at the time of starting of the fuel cell 2 by the control part 71 is complete | finished.

[Disabled discharge on startup route]
Next, a route in which no discharge is performed when the fuel cell 2 is started will be described.
In step S109, the control unit 71 turns off the switch 52 of the auxiliary circuit 50 (OFF of the auxiliary circuit 50). Specifically, as will be described later, since the IGSW 62 is continuously turned ON / OFF and the discharge at start-up and the discharge at stop are continuously repeated, the switch 52 is continuously turned ON, and the auxiliary resistance temperature When T1 becomes higher than the predetermined temperature T0, the auxiliary resistor 51 is protected by turning off the switch 52.
Note that when the switch 52 is OFF, it is continuously OFF.

  In step S110, as in step S102, the control unit 71 opens the shutoff valve 12, and hydrogen gas is supplied to the fuel gas flow path 4.

In this case, as described above, since the switch 52 is OFF, no discharge is performed at the time of startup. However, when the auxiliary resistance temperature T1 rises in this way, the switch 52 continues for a short time. It is thought that it is turned on.
Therefore, when the IGSW 62 is continuously turned ON / OFF, the scavenging gas hardly enters the fuel gas passage 4 of the fuel cell 2 in the first place, and the fuel gas passage 4 is almost filled with hydrogen gas. Therefore, it is considered that the small potential difference as described above does not occur, no current flows in the single cell, and no deterioration occurs.

In step S111, as in step S104, the controller 71 turns on the operation of the pump 21, and humidified air is supplied to the oxidant gas flow path 5.
Thereafter, the process proceeds to step S107.

<Control flow when fuel cell 2 is stopped (IGSW 23 is OFF)>
Next, a control flow when the fuel cell system 1 is stopped when the IGSW 62 is turned off will be described with reference to FIG.

When the IGSW 62 is turned off, the “control flow at stop” shown in FIG. 3 starts.
In step S201, the control unit 71 turns off the main switch 42.

[Auxiliary circuit compensation judgment]
In step 202A, as in step S101A (see FIG. 2) at the time of activation, the control unit 71 makes a compensation determination as to whether or not the auxiliary circuit 50 is within the compensation condition.
Specifically, when the control unit 71 determines that “the auxiliary resistance temperature T1 is equal to or lower than the predetermined temperature T0 (T1 ≦ T0) and the auxiliary circuit 50 is within the compensation condition” (Yes in S202A), the process proceeds to Step S203. It has come to go. On the other hand, if the control unit 71 determines that “the auxiliary resistance temperature T1 is higher than the predetermined temperature T0 (T1> T0) and the auxiliary circuit 50 is out of compensation conditions” (S202A / No), the process proceeds to step S209. ing.

A route that proceeds in the order of steps S203, S204A, S205, S206A, S207, and S208 corresponds to a route for executing discharge when the fuel cell 2 is stopped (discharge execution route at the time of stop).
On the other hand, the route that proceeds in the order of steps S209, S210, S211, and S212 corresponds to a route that does not perform discharge when the fuel cell 2 is stopped (a non-discharge-execution route when stopped). In the following, description will be given in the order of “stop discharge execution route” and “stop discharge non-execution route”.

[Discharge Discharge Execution Route]
In step S203, the control unit 71 closes the shutoff valve 12. Thereby, the supply of hydrogen gas from the hydrogen tank 11 to the fuel gas flow path 4 is stopped (hydrogen gas supply stop).

In step S204A, similarly to step S103A at the time of activation (see FIG. 2), the control unit 71 turns on the switch 52 of the auxiliary circuit 50 (ON of the auxiliary circuit 50, start of discharge at the time of stop). ). Even if a small potential difference occurs in each single cell constituting the fuel cell 2 by mixing the hydrogen gas and the scavenging gas in the fuel gas flow path 4 by turning on the switch 52, a current based on this potential difference is generated. In this case, the external auxiliary circuit 50 flows not in the single cell but is discharged. Thereby, deterioration of each single cell which comprises the fuel cell 2 can be prevented.
The controller 71 measures the auxiliary circuit ON time Δt1 (= ON time of the switch 52) based on the time from the clock 73, starting from the ON of the switch 52.

  In step S205, the controller 71 opens the on-off valve 32. As a result, the scavenging gas (non-humidified air) from the pump 21 flows into the oxidant gas flow path 5 through the pipe 21a, the fuel gas flow through the pipe 21a, the pipe 31, the on-off valve 32, and a part of the pipe 12a. The scavenging of the fuel gas passage 4 and the oxidant gas passage 5 is started (scavenging start).

(Fuel gas flow path state judgment)
In step S206A, the control unit 71 determines whether or not the fuel gas passage 4 is filled with scavenging gas. Specifically, the control unit 71 determines that “when the auxiliary circuit ON time Δt1 is longer than the predetermined time Δt0 (Δt1> Δt0), the scavenging gas is satisfied”, and “the auxiliary circuit ON time Δt1 is the predetermined time Δt0. Hereinafter, when (Δt1 ≦ Δt0), it is determined that the scavenging gas is not satisfied.

When the controller 71 determines that “the auxiliary circuit ON time Δt1 is longer than the predetermined time Δt0 and the fuel gas flow path 4 is filled with scavenging gas” (S206A / Yes), the process proceeds to step S207. .
On the other hand, when the control unit 71 determines that “the auxiliary circuit ON time Δt1 is equal to or less than the predetermined time Δt0 and the fuel gas passage 4 is not yet filled with the scavenging gas” (S206A / No), the process returns to step S206A. The determination in step S206A is repeated until the auxiliary circuit ON time Δt1 exceeds the predetermined time Δt0.

  In step S207, the control unit 71 turns off the switch 52 of the auxiliary circuit 50 (OFF of the auxiliary circuit 50). Note that when the switch 52 is turned off, the discharge at the time of stop is completed.

In step S208, after scavenging for a predetermined time, the controller 71 turns off the pump 21, closes the on-off valve 32, and ends scavenging.
And it progresses to an end and the process which concerns on the discharge at the time of the stop of the fuel cell 2 by the control part 71 is complete | finished.

[Discharge non-execution route when stopped]
Next, a route that does not discharge when the fuel cell 2 is stopped will be described.
In step S209, the switch 52 of the auxiliary circuit 50 is turned off (the auxiliary circuit 50 is turned off). Specifically, as will be described later, since the IGSW 62 is continuously turned on / off, and the discharge at the start and the discharge at the stop are continuously performed, the switch 52 is continuously turned on, and the auxiliary resistance temperature T1 is When the temperature is higher than the predetermined temperature T0, the auxiliary resistor 51 is protected by turning off the switch 52. Note that when the switch 52 is OFF, it is continuously OFF.

  In step S210, the control part 71 closes the cutoff valve 12 similarly to step S203. Thereby, the supply of hydrogen gas from the hydrogen tank 11 to the fuel gas passage 4 is stopped (hydrogen gas supply stop).

  In step S211, similarly to step S205, the controller 71 opens the on-off valve 32, and scavenging gas (non-humidified air) is supplied from the pump 21 to the oxidant gas channel 5 and the fuel gas channel 4. These scavenging starts (scavenging start).

  In step S212, as in step S208, the control unit 71 ends scavenging after scavenging for a predetermined time. After that, it is going to go to the end.

≪Operation of fuel cell system≫
Next, the operation of the fuel cell system 1 will be described with reference to the graphs and timing charts shown in FIGS. 4 and 5 as appropriate. Here, the case where the fuel cell system 1 is started / stopped under the freezing point (0 ° C.) condition will be described. That is, the case where scavenging is performed because the inside of the fuel cell 2 may freeze when the fuel cell 2 is stopped will be described.

<IGSW62 is normally turned on / off>
First, the case where the IGSW 62 is turned on / off as usual will be described with reference to FIGS. 2 and 3 in addition to FIG.
When the IGSW 62 is turned ON at “Point A”, the control unit 71 determines compensation of the auxiliary circuit 50 (S101A). Since the auxiliary resistor 51 is below the freezing point lower than the predetermined temperature T0, it is determined that the auxiliary circuit 50 is within the compensation condition (S101A / Yes). Then, hydrogen gas is supplied (S102), the auxiliary circuit 50 is turned on (S103A), and discharge at start-up is started. Next, air is supplied (S104).

  Then, after the predetermined time Δt0 has elapsed (S105A / Yes), the auxiliary circuit 50 is turned off at "B point" (S106), and the discharge at the time of startup ends. The auxiliary resistance temperature T1 gradually decreases as the auxiliary circuit 50 is turned off.

  Next, the main switch 42 is turned on (S107), and the fuel cell 2 generates power in response to the power demand of the external load 41 (S108). During power generation of the fuel cell 2, the auxiliary resistance temperature T <b> 1 drops below the freezing point that is the outside air temperature (“C point”) and becomes constant.

  Thereafter, when the IGSW 62 is turned off at the “D point” during the power generation of the fuel cell 2, the control unit 71 turns off the main switch 42 (S201) and performs compensation determination (S202A). In this compensation determination, since the auxiliary resistor 51 is below the freezing point lower than the predetermined temperature, it is determined that the auxiliary circuit 50 is within the compensation conditions (Yes in S202A). Next, the supply of hydrogen gas is stopped (S203), the auxiliary circuit 50 is turned on (S204A), and discharge at the time of stop is started. Then, scavenging gas is supplied (S205).

  Then, after the predetermined time Δt0 has elapsed (S206A / Yes), the auxiliary circuit 50 is turned off at the “point E” (S207), and the discharge at the time of stop ends. Then, after scavenging for a predetermined time Δt0 (S208), the process ends.

  In the present embodiment, it is assumed that the auxiliary resistance 51 is in contact with the outside air and the auxiliary resistance temperature T1 is lowered to the outside temperature when the auxiliary circuit 50 is turned off. Is not only the outside temperature, but only the ambient temperature of the installation site.

<IGSW 62 is continuously ON / OFF>
Next, with reference to FIGS. 2 and 3 in addition to FIG. 5, a case will be described in which the IGSW 62 is continuously turned ON / OFF in a short time.
Here, “Discharge at the first start” is linked with the first ON of the IGSW 62, “Discharge at the first stop” is interlocked with the first OFF of the IGSW 62, and “Second time is interlocked with the second ON. “Discharge at start-up” is performed in conjunction with “OFF for the second time”, and “Discharge at the second time stop” is performed. Therefore, a case where “the third discharge at the time of stop” is not performed will be described. However, the case where “auxiliary resistance temperature T1> predetermined temperature T0” is not limited to this, and it is needless to say that other cases may be used.

[IGSW 62 is turned on for the first time and discharged at the first start]
When the IGSW 62 is turned on at “point a”, the auxiliary circuit 50 is turned on through the same steps as in the case where the IGSW 62 is turned on normally (S103A), and the first start-up discharge is performed for a predetermined time Δt0. Is performed (S105A, Yes), the auxiliary circuit 50 is turned off at "b point" (S106).

[IGSW 62 is turned off for the first time and discharged when it is stopped for the first time]
If the IGSW 62 is turned off at “point c” immediately after the auxiliary circuit 50 is turned off and the fuel cell 2 is generating power and the auxiliary resistance temperature T1 is decreasing, the control unit 71 starts up at the time of startup shown in FIG. Control is switched from the control flow to the control flow at the time of stop shown in FIG.
Then, the control unit 71 turns off the main switch 42 (S201), determines that it is within the compensation condition (S202A / Yes), turns on the auxiliary circuit 50 (S204A), and performs the first stop discharge. Is done. Then, the auxiliary resistance temperature T1 starts to rise again.

[IGSW 62 is turned on for the second time and discharged for the second time]
When the IGSW 62 is turned on at “d point” during the first stop discharge and before the predetermined time Δt0 has elapsed since the auxiliary circuit 50 is turned on in the first stop discharge, the control is performed. The unit 71 performs control by switching from the control flow at the stop shown in FIG. 3 to the control flow at the start shown in FIG.
Then, the control unit 71 determines that the compensation condition is satisfied (S101A / Yes), the auxiliary circuit 50 is turned on (S103A), and the second start-up discharge is performed. Therefore, since the auxiliary circuit 50 is continuously turned on, the auxiliary resistance temperature T1 is continuously increased.

[Issue when IGSW 62 is turned off for the second time and stopped for the second time]
Next, when the IGSW 62 is turned OFF at “e point” during the second start-up discharge, the control unit 71 changes from the control flow at the start shown in FIG. 2 to the control flow at the stop shown in FIG. Switch and control.
Then, since the auxiliary resistance temperature T1 is equal to or lower than the predetermined temperature T0, it is determined that it is within the compensation determination (S202A, Yes), the auxiliary circuit 50 is kept on, and the second discharge at the stop is performed. Therefore, the auxiliary resistance temperature T1 continues to rise.

[IGSW62 is 3rd ON-no discharge at 3rd start]
Thereafter, a case where the IGSW 62 is turned ON during the second stop-time discharge will be described. When the IGSW 62 is turned on, the auxiliary resistance temperature T1 exceeds the predetermined temperature T0 as shown in FIG.

  When the IGSW 62 is turned on, the control unit 71 performs control by switching from the control flow at the time of stop shown in FIG. 3 to the control flow at the time of start shown in FIG. At this time, in the compensation determination of the auxiliary circuit 50 (S101A), since the auxiliary resistance temperature T1 is higher than the predetermined temperature T0, it is determined that the compensation condition is not satisfied (S101A / No), and the auxiliary circuit 50 is turned off (S109). . That is, the third start-up discharge is not performed. Thereby, the excessive temperature rise of the auxiliary resistor 51 is prevented, and as a result, the failure of the auxiliary resistor 51 is prevented.

  In addition, when the IGSW 62 is turned on for the third time as described above, the auxiliary circuit 50 is out of the compensation condition, so the third start-up discharge is not performed. However, the auxiliary circuit 50 is out of the compensation condition (auxiliary resistance temperature T1> The predetermined temperature T0) is limited to the case where the IGSW 62 is repeatedly turned ON / OFF continuously in a short time as described above, and therefore hydrogen gas and scavenging gas are present in the fuel gas flow path 4. It seems that there is almost no mixture. Therefore, no small potential difference occurs in the single cell of the fuel cell 2 and no current flows, so that it is considered that the electrolyte membrane 3 and the like do not deteriorate.

  As described above, according to the fuel cell system 1 according to the first embodiment, the auxiliary circuit 50 is provided while considering whether or not hydrogen gas and scavenging gas are mixed in the fuel gas flow path 4 of the fuel cell 2. Since it is determined whether or not the compensation condition is satisfied, the capacitance of the auxiliary resistor 51 constituting the auxiliary circuit 50 can be reduced. Therefore, such a fuel cell system 1 can be easily mounted on a fuel cell vehicle or the like.

<< Second Embodiment >>
Next, a fuel cell system according to a second embodiment will be described.

≪Configuration of fuel cell system≫
The fuel cell system according to the second embodiment does not include the temperature sensor 61 (see FIG. 1) for detecting the auxiliary resistance temperature T1, and the IGSW 62 is turned on / off based on the past history of discharge at start-up and discharge at stop. The current temperature of the auxiliary resistor 51 when turned off is estimated, and the estimated temperature (hereinafter, estimated auxiliary resistor temperature T2) is compared with a predetermined temperature T0 to determine whether the auxiliary circuit 50 is within the compensation condition. Determine whether.
In the fuel cell system according to the second embodiment, the time for turning on the auxiliary circuit 50 is preset with the energy consumed by the auxiliary resistor 51 (hereinafter referred to as auxiliary resistance consumption energy J1) when the auxiliary circuit 50 is turned on. Based on the comparison with the “predetermined auxiliary resistance consumption energy J0”, it is determined whether or not the fuel gas flow path 4 is filled with the same gas (hydrogen gas at startup, scavenging gas at stop).

<Auxiliary Resistance Data Storage Unit-Auxiliary Circuit ON / OFF History Storage Means>
In addition to the predetermined temperature T0 described in the first embodiment, the auxiliary resistance data storage unit 72 according to the second embodiment stores a discharge history at the time of start and stop. Specifically, the control unit 71 associates the time from the clock 73 with ON / OFF of the auxiliary circuit 50 (= ON / OFF of the switch 52) and stores it in the auxiliary resistance data storage unit 72. Yes. That is, the auxiliary resistance data storage unit 72 according to the second embodiment functions as “auxiliary circuit ON / OFF history storage means” in the claims.
The auxiliary resistance data storage unit 72 also stores a temperature increase rate of the auxiliary resistor 51 when the switch 52 is ON and a temperature decrease rate of the auxiliary resistor 51 when the switch 52 is OFF.

  Further, the “predetermined auxiliary resistance consumption energy J0” is stored in the auxiliary resistance data storage unit 72. The “predetermined auxiliary resistance consumption energy J0” means that different types of gas (hydrogen gas, scavenging gas) are mixed in the fuel gas flow path 4 of the fuel cell 2, so This is the electric energy consumed by the auxiliary resistor 51 until the fuel gas channel 4 is filled with the same gas (hydrogen gas at start-up, scavenging gas at stop).

≪Control flow of fuel cell system≫
Next, a control flow set in the fuel cell system according to the second embodiment will be described with reference to FIGS. In the drawings to be referred to, FIG. 6 is a flowchart showing control at the time of startup of the fuel cell system according to the second embodiment. FIG. 7 is a flowchart showing control when the fuel cell system according to the second embodiment is stopped.

<Control flow when the fuel cell 2 is started (when the IGSW 62 is ON)>
First, the control flow at the start of the fuel cell 2 will be described with reference to FIG.
As shown in FIG. 6, the startup control flow according to the second embodiment replaces step S <b> 101 </ b> B with step S <b> 103 </ b> A instead of step S <b> 101 </ b> A of the startup control flow (see FIG. 2) according to the first embodiment. Step S103B includes step S105B instead of step S105A.
Since the content of the other steps is the same as that of the first embodiment, description thereof is omitted here.

[Compensation judgment]
In step S101B, the control unit 71 reads from the auxiliary resistance data storage unit 72 the discharge history at startup / stop, the temperature increase rate / temperature decrease rate of the auxiliary resistor 51, and estimates the auxiliary resistance temperature T2 (= current). The temperature of the auxiliary resistor 51 is calculated.

  Next, the control unit 71 compares the estimated auxiliary resistance temperature T2 with a predetermined temperature T0 and determines whether or not the auxiliary circuit 50 is within the compensation condition. Specifically, it is determined that “when the estimated auxiliary resistance temperature T2 is equal to or lower than the predetermined temperature T0 (T2 ≦ T0), the auxiliary circuit 50 is within the compensation condition” (S101B · Yes), and “the estimated auxiliary resistance temperature T2 Is higher than the predetermined temperature T0 (T2> T0), the auxiliary circuit 50 is outside the compensation condition ”(S101B No).

In step S103B, as in step S103A (see FIG. 2), the auxiliary circuit 50 is turned on (= switch 52 is turned on).
However, in the second embodiment, the auxiliary circuit ON time Δt1 is not measured, and the auxiliary resistance consumption energy J1 (energy consumed by the auxiliary resistance 51) after the auxiliary circuit 50 is turned on is obtained from the ammeter 43 as a current value, Measurement is made based on the voltage value from the voltmeter 44 and the time from the clock 73.

[Fuel gas flow path state judgment]
In step S105B, the control unit 71 determines whether or not the fuel gas passage 4 is filled with hydrogen gas, as in step S105A (see FIG. 2) according to the first embodiment.

However, the specific method is different from that of the first embodiment, and the controller 71 determines that the fuel gas flow path 4 is hydrogen gas when the auxiliary resistance consumption energy J1 is larger than the predetermined auxiliary resistance consumption energy J0 (J1> J0). Is satisfied ”(S105B, Yes).
On the other hand, it is determined that “when the auxiliary resistance consumption energy J1 is equal to or less than the predetermined auxiliary resistance consumption energy J0 (J1 ≦ J0), the fuel gas flow path 4 is not yet filled with hydrogen gas” (S105B).・ No).

<Control flow when fuel cell 2 is stopped (when IGSW 62 is OFF)>
Next, a control flow when the fuel cell 2 is stopped will be described with reference to FIG.
As shown in FIG. 7, the control flow at the time of stop according to the second embodiment replaces step S202B with step S204A instead of step S202A of the control flow at stop according to the first embodiment (see FIG. 3). Step S204B includes step S206B instead of step S206A.
Since the content of the other steps is the same as that of the first embodiment, description thereof is omitted here.

[Compensation judgment]
In step S202B, similarly to step S101B (see FIG. 6), the control unit 71 calculates an estimated auxiliary resistance temperature T2 (= the estimated current temperature of the auxiliary resistance 51), and calculates the calculated estimated auxiliary resistance temperature T2. The predetermined temperature T0 is compared, and it is determined whether or not the auxiliary circuit 50 is within the compensation condition.
Specifically, it is determined that “when the estimated auxiliary resistance temperature T2 is equal to or lower than the predetermined temperature T0 (T2 ≦ T0), the auxiliary circuit 50 is within the compensation condition” (S202B · Yes), and “the estimated auxiliary resistance temperature T2 Is higher than the predetermined temperature T0 (T2> T0), the auxiliary circuit 50 is outside the compensation condition ”(S202B, No).

  In step S204B, similarly to step 103B, the control unit 71 turns on the auxiliary circuit 50 and measures the auxiliary resistance consumption energy J1 after the auxiliary circuit 50 is turned on.

[Fuel gas flow path state judgment]
In step S206B, the controller 71 determines whether or not the fuel gas passage 4 is filled with scavenging gas.
Specifically, the control unit 71 determines that “the fuel gas flow path 4 is filled with scavenging gas when the auxiliary resistance consumption energy J1 is greater than the predetermined auxiliary resistance consumption energy J0 (J1> J0)”. (S206B / Yes). On the other hand, it is determined that “when the auxiliary resistance consumption energy J1 is equal to or less than the predetermined auxiliary resistance consumption energy J0 (J1 ≦ J0), the fuel gas flow path 4 is not yet filled with scavenging gas” (S206B).・ No).

  Therefore, according to the fuel cell system according to the second embodiment, the temperature sensor 61 that detects the temperature of the auxiliary resistor 51 can be omitted. That is, the configuration of the fuel cell system is simplified, and the fuel cell system can be easily mounted on a fuel cell vehicle.

  As mentioned above, although an example was described about each suitable embodiment of the present invention, the present invention is not limited to the above-mentioned each embodiment, and the composition concerning each above-mentioned embodiment is combined in the range which does not deviate from the meaning of the present invention, In addition, for example, the following changes can be made.

  In the above-described second embodiment, the auxiliary circuit is calculated by calculating the estimated auxiliary resistance temperature T2 based on the past start-up discharge / stop discharge history and comparing the estimated auxiliary resistance temperature T2 with the predetermined temperature T0. However, if the start-up discharge / stop-time discharge is performed a predetermined number of times (for example, 5 times) within the past predetermined time (for example, 30 minutes), the auxiliary circuit 50 is out of the compensation condition. You may make it determine with it.

  In addition, in the determination (S105A, S206A, S105B, S206B) of whether or not the fuel gas channel 4 is filled with hydrogen gas at the time of startup and scavenging gas at the time of stop, the auxiliary circuit ON time Δt1 according to the first embodiment is set. The determination based on and the determination based on the auxiliary resistance consumption energy J1 according to the second embodiment may be performed in an overlapping manner to improve the determination accuracy.

  In the first embodiment described above, the case where the fuel cell system 1 is mounted on a fuel cell vehicle has been described. However, the fuel cell system 1 may be mounted on a ship or an aircraft, or may be a stationary type. The fuel cell system 1 for home use may be used.

1 is a configuration diagram of a fuel cell system according to a first embodiment. FIG. It is a flowchart which shows the control at the time of starting of the fuel cell system which concerns on 1st Embodiment. It is a flowchart which shows the control at the time of the stop of the fuel cell system which concerns on 1st Embodiment. It is a temperature change and timing chart of auxiliary resistance of the fuel cell system concerning a 1st embodiment. It is a temperature change and timing chart of auxiliary resistance of the fuel cell system concerning a 1st embodiment. It is a flowchart which shows the control at the time of starting of the fuel cell system which concerns on 2nd Embodiment. It is a flowchart which shows the control at the time of the stop of the fuel cell system which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell system 2 Fuel cell 4 Fuel gas flow path 11 Hydrogen tank 12 Shut-off valve 21 Pump 41 External load 42 Main switch 43 Ammeter 44 Voltmeter 50 Auxiliary circuit 51 Auxiliary resistance 52 Switch 61 Temperature sensor (temperature detection means)
62 IGSW (startup switch)
70 ECU
71 Control unit (compensation determination means, auxiliary circuit control means)
72 Auxiliary resistance data storage section (auxiliary circuit ON / OFF history storage means)
73 clock

Claims (4)

A fuel cell that generates electricity by reaction of the reaction gas; an auxiliary circuit having an auxiliary resistor connected to the fuel cell; a compensation determination unit that determines whether the auxiliary circuit is within compensation conditions; and a determination by the compensation determination unit An auxiliary circuit control means for controlling ON / OFF of the auxiliary circuit based on
The auxiliary circuit control means, when starting the fuel cell,
A fuel cell system, wherein the auxiliary circuit is turned on when the auxiliary circuit is within compensation conditions, and the auxiliary circuit is not turned on when the auxiliary circuit is out of compensation conditions. A fuel cell that generates power by reaction of a reaction gas, an auxiliary circuit that has an auxiliary resistor and is connected to the fuel cell, a compensation determination unit that determines whether the auxiliary circuit is within compensation conditions, and a determination by the compensation determination unit An auxiliary circuit control means for controlling ON / OFF of the auxiliary circuit based on
The auxiliary circuit control means, when the fuel cell is stopped,
A fuel cell system, wherein the auxiliary circuit is turned on when the auxiliary circuit is within compensation conditions, and the auxiliary circuit is not turned on when the auxiliary circuit is out of compensation conditions. A temperature detecting means for detecting the temperature of the auxiliary resistor,
The compensation determining means determines that the auxiliary circuit is out of compensation conditions when the temperature of the auxiliary resistor is higher than a predetermined temperature, and the auxiliary circuit compensates when the temperature of the auxiliary resistor is equal to or lower than the predetermined temperature. The fuel cell system according to claim 1 or 2, wherein it is determined that the condition is satisfied. Auxiliary circuit ON / OFF history storage means for recording the ON / OFF history of the auxiliary circuit is further provided,
3. The fuel cell according to claim 1, wherein the compensation determination unit determines whether the auxiliary circuit is within a compensation condition based on a past ON / OFF history of the auxiliary circuit. system.

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