JP2007258129A - Fuel cell system and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system and a fuel cell operation method capable of appropriately operating a fuel cell while warming the fuel cell when the fuel cell is warmed up. <P>SOLUTION: This fuel cell system 1 or 2 is provided with the fuel cell 10, a combustion heater 56 for warming it up, and a means 62 for detecting the condition of the fuel cell. When it is determined from the condition of the fuel cell that the fuel cell is in a predetermined condition, the combustion heater is operated by a predetermined extent. Then, warm-up efficiency can be enhanced by operating the combustion heater nearly at the upper limit of its capability. The output power of the fuel cell is restricted so that the combustion heater can be operated during the warming-up by the predetermined extent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for warming up a fuel cell while operating the fuel cell in a fuel cell system in which fuel gas and oxidant gas are also supplied to a combustion heater while the fuel cell is warmed up.

Since the fuel cell has high energy conversion efficiency, the fuel cell has a low ability to warm itself with lost heat, and has a characteristic that power generation efficiency becomes extremely low when the temperature is lower than a specified temperature. For this reason, it may be difficult to obtain sufficient generated power immediately after starting, particularly in a system that may be exposed to a cold state such as a vehicle. Furthermore, the power generation efficiency is further reduced at a low temperature at which part of the cell electrolyte membrane is frozen. In order to cope with the start in such a low temperature state, various fuel cell warm-up systems have been proposed so far. For example, there is a fuel cell warming system in which a combustion heater is provided in a cooling water circulation system for heating or cooling the fuel cell, and fuel is supplied to the combustion heater from a fuel source common to the fuel cell (see Patent Document 1). ).
Japanese Unexamined Patent Publication No. 7-94202 (paragraph 0073, FIG. 11)

  However, when warming up while operating the fuel cell, it is necessary to supply reaction gas (fuel gas and oxidant gas) to both the fuel cell and the combustion heater. At this time, if all the requirements for both operable regions are satisfied, the maximum required fuel cell air amount that enables stable power generation at the maximum output of the fuel cell and the air-fuel ratio required for complete combustion when the heater generates maximum heat can be secured. An air pump capable of supplying a total amount with the maximum required amount of combustion heater air is required, and the system becomes large. Also, if there are no restrictions on the operation of the fuel cell, when the fuel cell temperature is low and the power generation performance is degraded, etc., if a high current is drawn from the fuel cell in order to promote warm-up, the stack performance will be reduced. There is also a risk of deterioration.

  Therefore, the present invention provides a fuel cell system capable of operating a fuel cell appropriately while warming up the fuel cell, and a method for operating the fuel cell system. Objective.

The invention according to claim 1 is a fuel cell that generates electric power by a reaction between a fuel gas and an oxidant gas, a combustion heater that causes the fuel gas and the oxidant gas to react and burn, and the fuel cell during warm-up of the fuel cell. And the reaction gas supply means for supplying the fuel gas and the oxidant gas to the combustion heater, the state detection means for detecting the state of the fuel cell, and the fuel cell state. When it is determined that there is a warming-up unit that operates the combustion heater by a predetermined amount, and during the operation of the warming-up unit, an output limit that limits the output of the fuel cell so that the combustion heater can operate by the predetermined amount Means.
According to the fuel cell system having this configuration, the fuel cell can be appropriately operated while warming up the fuel cell. By limiting the output of the fuel cell, it is possible to reduce the amount of reaction gas consumed in the fuel cell, so that it is not necessary to increase the size of the reaction gas supply means (particularly the compressor of the oxidant gas supply means). .

The fuel cell system according to claim 2 is characterized in that the warm-up means includes an upper limit operation means for operating the combustion heater at a substantially upper limit of its capacity.
According to the fuel cell system having this configuration, since the combustion heater operates at almost the upper limit of its capacity, the warm-up efficiency is improved.

The fuel cell system according to claim 3, wherein the predetermined state is an unstable power generation state of the fuel cell.
According to the fuel cell system having this configuration, when the fuel cell is in an unstable power generation state, the fuel cell can be appropriately operated while warming up the fuel cell.

The fuel cell system according to any one of claims 1 to 3, wherein the output limiting unit includes a power generation stop unit that stops power generation of the fuel cell. .
According to the fuel cell system of this configuration, by stopping the power generation of the fuel cell, the consumption amount of the reaction gas of the fuel cell can be made almost zero, and all the capabilities of the reaction gas supply means are directed to the combustion heater. Therefore, further miniaturization of the reaction gas supply means and warm-up of the fuel cell are promoted.

The invention according to claim 5 includes a fuel cell that generates electric power by a reaction between the fuel gas and the oxidant gas, and a combustion heater that causes the fuel gas and the oxidant gas to react with each other and burn the fuel cell. An operation method of a fuel cell system in which fuel gas and oxidant gas are also supplied to a combustion heater, wherein the fuel cell is in a predetermined state from a state detection step of detecting the state of the fuel cell, and the state of the fuel cell A warm-up step for operating the combustion heater by a predetermined amount, and an output for limiting the output of the fuel cell so that the combustion heater can be operated by the predetermined amount during the warm-up step. And a limiting step.
The operation method of the fuel cell system according to claim 5 has the same effect as that of the invention according to claim 1.

  According to the present invention, when the fuel cell is warmed up, the fuel cell can be appropriately operated while warming up the fuel cell.

Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention and the accompanying drawings.
In addition, when showing the same element in several drawing, the same referential mark is attached | subjected.
<First Embodiment>
FIG. 1 is a schematic block diagram conceptually showing a configuration example of a parallel type fuel cell system according to a first embodiment of the present invention. Examples of a method for supplying fuel (fuel gas and oxidant gas (air)) to the fuel cell and the combustion heater include a series system that supplies fuel to the combustion heater via the fuel cell, and a fuel cell and a combustion heater. There is a parallel system that supplies each in parallel. Here, the latter will be described as an example. Hereinafter, the fuel cell system of the present invention will be described as being mounted on a vehicle, but it is not necessarily required to be mounted on a vehicle.
In FIG. 1, a fuel cell system 1 according to this embodiment includes an anode (not shown), a cathode (not shown), and an electrolyte membrane (not shown) sandwiched between both electrodes, as is well known. A fuel cell 10 that generates electric power using the generated fuel gas and oxidant gas, an anode system that supplies and discharges hydrogen (fuel gas) to the anode of the fuel cell 10 (described later), and oxygen to the cathode of the fuel cell 10 A cathode system for supplying and discharging air (oxidant gas, reaction gas) (described later), a warming system for warming up the fuel cell 10 (described later), and a control system for controlling the entire fuel cell system 1 (described later) It has.

  The fuel cell (fuel cell stack) 10 is a polymer electrolyte fuel cell configured by stacking a plurality of single cells. A single cell is composed of an MEA (Membrane Electrode Assembly) in which both surfaces of an electrolyte membrane (solid polymer membrane) are sandwiched between an anode (fuel electrode) and a cathode (air electrode), and a pair of sandwiching the MEA And a separator. Each separator has a groove for supplying hydrogen or oxygen to the entire surface of the MEA constituting each single cell, a through-hole for introducing hydrogen and oxygen to all the single cells, and the like. It functions as an anode channel 11 and a cathode channel 12.

  Then, when hydrogen is supplied to each anode via the anode flow path 11 and air containing oxygen is supplied to each cathode via the cathode flow path 12, the catalyst (Pt or the like) included in the anode and the cathode is supplied. An electrochemical reaction occurs, and as a result, a potential difference (so-called OCV (Open Circuit Voltage)) is generated in each single cell. In this way, when an external load 41 such as a travel motor (not shown) is connected to the fuel cell 10 in which a potential difference has occurred in each single cell, the fuel cell 10 continuously generates power. The separator is formed with a heat exchange fluid passage 13 through which a heat exchange fluid for heating the fuel cell 10 flows.

The anode system mainly includes a hydrogen tank 21 in which hydrogen is stored, and a cutoff valve 22 that intermittently opens or closes a flow path of hydrogen gas from the hydrogen tank 21. A pipe 21a, a shut-off valve 22, a pipe 22a, and an anode flow path 11 are sequentially connected from the hydrogen tank 21 toward the downstream side, and the shut-off valve is operated by a fuel cell (FC) control unit 90 described later. When 22 is opened, hydrogen is supplied to the anode channel 11. The piping 22a is provided with a pressure reducing valve (not shown) so that the pressure of hydrogen is appropriately reduced.
A pipe 22b is connected to the downstream side of the anode flow path 11, and the anode off gas discharged from the anode is discharged to the outside through the pipe 22b.

The cathode system mainly includes a compressor 31 (supercharger, oxidant gas supply source). The compressor 31 is connected to the cathode flow path 12 via the pipe 31 a, and when operated according to a command from the FC control unit 90, oxygen-containing air is supplied to the cathode flow path 12. The pipe 31a is provided with a humidifier (not shown) so that the air sent to the cathode is appropriately humidified.
A pipe 31b is connected to the downstream side of the cathode channel 12, and the cathode off-gas discharged from the cathode is discharged to the outside through the pipe 31b.

The warm-up system is a system that appropriately heats the heat exchange fluid flowing through the heat exchange fluid flow path 13 of the fuel cell 10. The warm-up system includes a bypass cutoff valve 50 inserted in the branch path of the pipe 31 a from the compressor 31, a cutoff valve 51 inserted in the branch path of the pipe 22 a downstream of the cutoff valve 22, and a bypass cutoff valve 50. A hydrogen gas from the shut-off valve 51 is introduced into the air flow, and a catalyst such as a mixer 53 and Pt for mixing the air and the hydrogen gas to generate a combustion mixed gas is built in, and from the mixer 53 under the catalyst. The combustion mixture gas is caused to undergo a combustion reaction to generate high-temperature exhaust gas, and heat exchange is performed by exchanging heat between the high-temperature exhaust gas sent from the catalyst combustor 54 and the heat exchange fluid. A heat exchanger 55 that heats the fluid, a pump 61 that circulates the heat exchange fluid heated by the heat exchanger 55 through the heat exchange fluid flow path 13 of the fuel cell 10, and pipes 61a to 61c for circulating the heat exchange fluid. Prepare.
The elements 21, 21a, 22, 22a, 31, 31a, 50, and 53 constitute a main part of the reactive gas supply means described in the claims.

The catalytic combustor 54 and the heat exchanger 55 can be integrated and realized as a combustion heater 56. The exhaust gas after the heat exchange is discharged to the outside through a pipe. A temperature sensor 62 is attached to the pipe 61a to detect the temperature T of the heat exchange fluid flowing through the pipe 61a. Since the heat exchange fluid immediately after being discharged from the fuel cell 10 flows through the pipe 61a (see FIG. 1), the temperature T detected by the temperature sensor 62 is considered to be substantially equal to the temperature of the fuel cell 10. The heat exchange fluid is a so-called radiator liquid (an antifreeze liquid or a refrigerant), and has, for example, ethylene glycol or the like as a main component.
The warming-up means mentioned in the claims includes elements 56, 61, 61a to 61c, 13 in addition to the reactive gas supply means.

  The control system includes various sensors in addition to the temperature sensor 62 in order to obtain information necessary for control. For example, in the fuel cell system 1 of the present embodiment, a voltage sensor is arranged for each single cell so that the electromotive force for each single cell constituting the fuel cell 10 can be measured. Electric power is taken out from the fuel cell 10 via a VCU (voltage control unit) 14. Here, the VCU 14 is connected to the fuel cell 10 via a current-voltage sensor (IV sensor) 15. Furthermore, an energy storage 46 such as a battery or a capacitor is connected to the VCU 14 via a DC / DC converter 44 that converts the output of the fuel cell 10 into a voltage suitable for charging, so as to store surplus power. The compressor 31 is controlled by a control signal C31 output from the FC control unit 90. Furthermore, the control system of the fuel cell system 1 according to the present embodiment includes an ignition switch 80 that functions as a power switch of the vehicle.

  The FC control unit 90 may be realized as an independent control device, or may be realized by being incorporated in another ECU. As is well known, the FC control unit 90 includes a CPU, a non-volatile memory, a RAM, various interfaces, electronic circuits, and the like (not shown) as well as various controllers (control units) constituting the ECU.

  According to the principle of the present invention, immediately after the ignition is turned on, fuel (hydrogen gas) and air are preferentially used for necessary warm-up as needed, and further, the fuel and air that can be supplied are heated to the fuel cell 10. Perform machine priority operation. Therefore, the hydrogen gas amount Qhreq and air amount Qareq per unit time necessary for the maximum operation of the catalytic combustor 54, the hydrogen gas supply capacity Qhmax per unit time by the hydrogen tank 21 and the shutoff valve 22, and the unit time by the compressor 31 If the air supply capability Qamax is known, it is understood that Qhmax-Qhreq hydrogen gas and Qamax-Qareq air per unit time can be sent to power generation (that is, the fuel cell 10). In view of the air-fuel ratio (stoichiometry) required for power generation in the fuel cell 10, the maximum power generation amount Pfcmax of the fuel cell 10 at the time of maximum warm-up is determined by the lesser of Qhmax-Qhreq hydrogen gas and Qamax-Qareq air. . Specifically, for example, the data representing the relationship between the hydrogen gas supply amount per unit time and the generated power when the air supply amount to the fuel cell 10 is not limited, and the hydrogen gas supply amount to the fuel cell 10 By storing data representing the relationship between the air supply amount per unit time and the generated power when there is no limit, and referring to these, the maximum power generation amount Pfcmax can be obtained.

  As will be described in detail below, the FC control unit 90 includes a shutoff valve 22, a compressor according to signals from the voltage sensor for each single cell, the IV sensor 15, the temperature sensor 61, the ignition switch 80, and the like. 31, the fuel cell system 1 is controlled by appropriately outputting control signals C22, C31, C50, C51 and C61 for controlling the shutoff valves 50 and 51 and the pump 61, respectively.

  FIG. 2 is a flowchart showing a flow of processing according to an embodiment of the present invention executed by the FC control unit 90 when the IG 80 is switched from OFF to ON. As an initial state, when the IG 80 is OFF, all the shut-off valves 22, 50 and 51 are in a shut-off state, and power is not supplied to the compressor 31 and the pump 61 immediately after the IG 80 is turned on. Further, according to the present embodiment, the compressor 31 of the fuel cell 10 uses the power of the energy storage 46 until the fuel cell 10 starts generating power. When the energy storage 46IG80 is turned on, in FIG. 2, the FC controller 90 first operates the compressor 31 and the shutoff valve 22 in step S1 to supply the fuel cell 10 with a predetermined amount of air and hydrogen gas. Then, the fuel cell 10 is started. In this case, the energy storage 46 compressor 31 is driven by the power of the energy storage 46. Subsequently, in step S3, in order to check the state of the fuel cell 10, the temperature of the fuel cell 10 (hereinafter referred to as “system temperature”) T and the start of each unit cell with the output electrode of the fuel cell 10 released. Measure power. Further, the output voltage V and the output current I of the fuel cell 10 in a state where a reference load (for example, an appropriate electrical accessory 42) is connected are measured. Step S3 is a state detection step, and hardware and software resources that execute the state detection step S3 are state detection means.

  In determination step S5, it is determined whether warm-up is necessary based on the data measured in step S3. As the determination method, for example, (1) when the system temperature T is lower than the predetermined temperature T0, (2) the output voltage V and the current I are set to the IV curve using the IV curve in a predetermined state of the fuel cell 10. Or (3) if the output voltage of the single cells constituting the fuel cell 10 varies, it is considered that the fuel cell 10 is in an unstable power generation state, so that it is determined that warm-up is necessary. As a specific method of the determination (3), for example, (3a) the dispersion or standard deviation of the electromotive force of the single cell is smaller than a predetermined reference value, or (3b) the voltage of the single cell having the lowest output is a predetermined threshold value. In addition to the method of determining that the output voltage of the single cell varies when it is smaller, various methods are conceivable. FIG. 4 is a graph showing an example of an IV characteristic curve of the fuel cell 10 used for determining whether warm-up is necessary. Since this curve is used as a criterion for determining whether or not warm-up is required, it is obtained by actual measurement under predetermined environmental conditions such as a minimum temperature that does not require warm-up or a temperature that requires warm-up. If the point determined by the output current I and the output voltage V of the fuel cell 10 (referred to as operating point (I, V)) is below the curve in FIG. 3 (warm-up required region), the electromotive force of the fuel cell 10 is Since it is insufficient and the performance inherent in the fuel cell is not exhibited, it is determined that warm-up is necessary, and if it is on the upper side (warm-up unnecessary area), it is determined that warm-up is unnecessary. Therefore, the operating point (I, V) of the fuel cell 10 in a state in which a load having a predetermined resistance value (for example, an electrical accessory having a known appropriate resistance value) is connected is below the IV curve in FIG. If there is, it is determined that warm-up is necessary.

  Returning to the flowchart of FIG. 2, when it is determined in step S5 that the warm-up is not required (in the case of No), the fuel cell 10 is in a good state, so that the normal operation of the fuel cell 10 is performed in a normal manner. In step S6, the power source of the compressor 31 is switched from the energy storage 46 to the fuel cell 10 by switching means (not shown). Then, normal operation is started.

  When the vehicle fuel cell needs to be warmed up, the fuel cell can be warmed up while consuming a certain amount of power. There is a case where it is preferable to perform only warm-up (warm-up only mode). Therefore, when it is determined in the determination step S5 that the warm-up is necessary, it is determined in a further determination step S7 whether or not the warm-up only mode should be set. The determination in this case is made, for example, based on whether or not the system temperature T is higher than a temperature T1 (for example, a freezing point) that is lower than the predetermined temperature T0.

  When it is determined in the determination step S7 that the operation should be performed in the warm-up only mode (in the case of Yes), the process proceeds to step S17, where the temperature of the fuel cell 10 is quickly raised, and the fuel cell 10 can be operated in a short period of time. Therefore, the combustor 54 is operated to the maximum in order to warm up the fuel cell 10 as much as possible (including the case where power generation is not performed at all). Since this warm-up method (warm-up only mode) is different from the main line of the present invention, detailed description thereof will not be given here. However, in the warm-up only mode, the compressor 31 is preferably driven by the energy storage 46 so as not to consume the power of the fuel cell 10 as much as possible. While warming up, in determination step S19, it is determined whether or not the fuel cell 10 is in a state capable of generating power. When power generation is not possible (in the case of No), it returns to step S17 and continues warming up. When power generation is possible (in the case of Yes), the process proceeds to S9 described later, and warm-up priority operation is performed.

In the determination step S7, when it is determined that the fuel cell 10 can be operated and should be operated with priority to warm-up rather than the warm-up only mode (in the case of No), warm-up is performed while allowing operation to be performed. Perform priority operation. Therefore, in step S9, in the present embodiment, in order to complete the warm-up and perform the normal operation as soon as possible, in order to perform the maximum operation of the warm-up system, per unit time required by the catalytic combustor 54 at the maximum operation. The hydrogen gas amount Qrh and the air amount Qra are supplied, and appropriate electric power is supplied to the pump 61. At this time, in consideration of various situations, an appropriate degree of operation may be performed instead of the maximum operation of the catalytic combustor 54. (Step S9 and step S9a described later are warm-up steps, and the hardware and software resources for executing warm-up step S9 or S9a constitute warm-up means and include upper-limit operation means.) In step S11, the process waits until the warm-up is completed. During this time, control is performed to suppress the output of the fuel cell 10 to be equal to or less than the power generation amount Pfcmax of the fuel cell 10 during the maximum warm-up by an interrupt subroutine described later.
<Modification>

In the determination step S7, any one of the determination criteria (1), (2), (3a) and (3b) is used, but any two of the determination criteria (1), (2) and (3) are used. You may judge by combining the above.
In connection with step S3, several items for checking the state of the fuel cell have been described. Actually, in the state checking step S3, only the necessary items in the determining step S7 need be measured.
<Second Embodiment>

  In the first embodiment, the compressor 31 of the fuel cell 10 uses the power of the energy storage 46 during warm-up, and uses the power generated by the fuel cell 10 during normal operation without warm-up. . In the second embodiment, when the fuel cell system 1 is started up and in the warm-up only mode, the compressor 31 is driven by a battery, and otherwise, the compressor 31 is basically driven by the electric power of the fuel cell 10. FIG. 4 is a flowchart showing a flow of processing of a fuel cell control program executed in response to turning on of the IG 80 in the parallel type fuel cell system according to the second embodiment of the present invention. Since the second embodiment is the same as the first embodiment except that the flowchart in FIG. 2 is replaced with the flowchart in FIG. 4, only the flowchart in FIG. 4 will be described. Further, the flowchart of FIG. 4 shows that the compressor power supply switching step S6 is not executed after the warm-up only mode is completed (that is, after step S15), but only after the No branch of the determination step S5. Except that S9 is replaced with S9a, the process is the same as the flowchart of FIG.

  Therefore, as in the first embodiment, when the IG 80 is OFF, the power source of the compressor PDU 32 is switched to the energy storage 46 side by switching means (not shown), and when starting the fuel cell 10 in step S1, The compressor 31 is driven by an energy storage 46. When it is determined in step S5 that warm-up is unnecessary (in the case of No) and normal operation is performed, the compressor power supply is switched from the energy storage 46 to the fuel cell 10 in step S6.

  In the determination step S7, when it is determined that the warm-up priority operation should be performed instead of the warm-up only mode (in the case of No), the power of the compressor 31 is switched from the energy storage 46 to the fuel cell 10 by the switching means (not shown) in step S9a. And the warm-up system including the catalyst combustor 54 and the pump 61 is operated at maximum. After the warm-up is completed (Yes in determination step S11), the process proceeds to normal operation through steps S13 and S15. However, since the compressor 31 is continuously driven by the fuel cell 10, it is not necessary to switch the compressor power source.

  Incidentally, when operating in the warm-up only mode in the determination step S7 (in the case of Yes), as described in relation to the first embodiment, in order to minimize the power consumption of the fuel cell 10, step S1 is performed. The compressor 31 is driven by the energy storage 46 with the setting of.

Although the present embodiment basically provides the same effect as that of the first embodiment, the compressor 31 is driven by the generated power of the fuel cell 10 in the warm-up priority operation of the present embodiment.
<Third Embodiment>

In the first and second embodiments, the parallel type fuel cell system has been described as an example, but the present invention is also applicable to a series type fuel cell system.
FIG. 5 is a schematic block diagram conceptually showing an example of the configuration of a series-type fuel cell system according to the third embodiment of the present invention. In the fuel cell system 2 of FIG. 5, the shut-off valve 51 is connected to the pipe 22 b downstream of the anode flow path 11 of the fuel cell 10, and the shut-off valve 50 is connected to the pipe 31 b downstream of the cathode flow path 12 of the fuel cell 10. Thus, the fuel cell system 1 is the same as the fuel cell system 1 of FIG. 1 except that the fuel cell 10 and the combustion heater 56 are connected in series.
The fuel cell control program executed when the IG 80 is turned on is also the same as that of the fuel cell system 1 of FIG. Needless to say, the above-described modification can also be applied to the fuel cell system 2 of FIG.
<Modification>

The above is merely an example of an embodiment for explaining the present invention. Accordingly, it is easy for those skilled in the art to make various changes, modifications, or additions to the above-described embodiments in accordance with the technical idea or principle of the present invention.
For example, in the embodiment shown in FIGS. 1 and 6, the system temperature is measured by the pipe 61 a downstream of the heat exchange fluid flow path 13 of the fuel cell 10, but is discharged from the anode flow path 11 of the fuel cell 10. The temperature of the anode off gas may be measured.
1 and 5, the ECU 90 includes the FC control unit 90 and the drive control unit 94, and these are described as performing the various controls described above. However, as will be apparent to those skilled in the art, the present invention can be implemented regardless of the names and configurations of the elements that perform the control as long as the various controls described above are performed.

  Although elements not directly related to the description of the present invention are omitted in FIGS. 1 and 5, various elements other than those illustrated are used in the preferred embodiment. For example, the anode system may be provided with a circulation path for returning the hydrogen gas discharged from the fuel cell 10 to the hydrogen gas supply path of the fuel cell 10 and a purge valve for discharging the hydrogen gas from the circulation path. Note that in the third embodiment of FIG. 5, the hydrogen gas discharged from the purge valve is supplied to the combustion heater 56.

  In the above embodiment, an example in which the present invention is applied to a vehicle is used. However, the present invention is not limited to a vehicle and can be used for any ship as long as it is a system that uses a common fuel source for a fuel cell and a combustion heater. Applicable.

1 is a schematic block diagram conceptually showing a configuration example of a parallel type fuel cell system according to a first embodiment of the present invention. It is a flowchart which shows the flow of a process of the fuel cell control program performed according to ON of IG80. It is a graph which shows an example of the IV characteristic curve of the fuel cell 10 used for judgment whether warming-up is required. It is a flowchart which shows the flow of a process of the fuel cell control program performed according to ON of IG80 in the parallel type fuel cell system by the 2nd Embodiment of this invention. It is a schematic block diagram which shows notionally the structural example of the series type fuel cell system by the 3rd Embodiment of this invention.

Explanation of symbols

1, 2 Fuel cell system of the present invention 10 Fuel cell 14 VCU
15 I-V sensor 16 Current sensor 21 Hydrogen tank 22, 50, 51 Shut-off valve 31 Compressor 44 DC / DC converter 46 Energy storage 53 Mixer 54 Catalytic combustor 55 Heat exchanger 56 Combustion heater 61 Pump 80 Ignition switch (IG)
90 Fuel cell controller (FC controller)

Claims (5)

A fuel cell that generates electricity by a reaction between the fuel gas and the oxidant gas;
A combustion heater for reacting and burning fuel gas and oxidant gas;
Reactive gas supply means for supplying the fuel gas and the oxidant gas to the fuel cell and the combustion heater during warm-up of the fuel cell;
State detecting means for detecting the state of the fuel cell;
When it is determined from the state of the fuel cell that the fuel cell is in a predetermined state, warm-up means for operating the combustion heater by a predetermined amount;
A fuel cell system comprising output limiting means for limiting the output of the fuel cell so that the combustion heater can operate only to the predetermined degree during operation of the warm-up means.   2. The fuel cell system according to claim 1, wherein the warm-up means includes upper-limit operation means for operating the combustion heater at a substantially upper limit of its capacity.   The fuel cell system according to claim 1, wherein the predetermined state is an unstable power generation state of the fuel cell.   The fuel cell system according to any one of claims 1 to 3, wherein the output limiting unit includes a power generation stop unit that stops power generation of the fuel cell. A fuel cell for generating electricity by a reaction between the fuel gas and the oxidant gas; and a combustion heater for causing the fuel gas and the oxidant gas to react with each other and combusting the fuel cell. In the fuel cell system that is supplied with the agent gas and generates power after warm-up,
A state detecting step of detecting the state of the fuel cell;
When it is determined from the state of the fuel cell that the fuel cell is in a predetermined state, a warm-up step for operating the combustion heater by a predetermined amount;
A fuel cell system operating method comprising: an output limiting step of limiting the output of the fuel cell so that the combustion heater can be operated by the predetermined degree during the warm-up step.

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