JP2005209467A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly extract power without putting a fuel cell in an overloaded condition by carrying out optimum output limiting control taking into consideration of a conditioning state of the fuel cell and the condition of its performance deterioration. <P>SOLUTION: When a control device 6 carries out output limiting control of the fuel cell 1, an output limiting value is determined by using integrated power, which is the integrated value of an amount of power extracted from the fuel cell in the past, as a parameter, and based on this, the output limiting control for the fuel cell 1 is carried out. Therefore, optimum output limiting control taking into consideration of conditioning of the fuel cell 1 or the condition of its performance deterioration becomes possible, and power can be properly extracted without putting the fuel cell 1 in an overloaded condition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell system, and more particularly, to a technique for appropriately taking out electric power without bringing a fuel cell into an overload state.

  A fuel cell system is a power generation system in which hydrogen as a fuel and air as an oxidant are supplied to a fuel cell to cause an electrochemical reaction in the fuel cell to obtain generated power. In such a fuel cell system, it is known that when a high output is transiently taken out from the fuel cell, the output voltage of the fuel cell may be suddenly lowered or flooded (water clogged). In order to avoid the problem, various studies have been made to limit the output from the fuel cell as necessary (see, for example, Patent Document 1 and Patent Document 2).

  In Patent Document 1, when the output is transiently taken out from the fuel cell, the upper limit output is calculated from the pressure or flow rate of the gas supplied to the fuel cell by the power generation amount control device, and the fuel cell is based on the upper limit output. A technique for preventing a sudden drop in output voltage due to overload by limiting the output to be extracted is disclosed.

Further, in Patent Document 2, in a fuel cell system having a solid plate fuel cell, there is a concern on the cathode electrode side, which is a concern when a high output is transiently taken out from the fuel cell in a low temperature state such as immediately after startup. In order to avoid sudden flooding, when the operating temperature of the fuel cell is in a low temperature range, the fuel cell can be controlled by limiting the amount of hydrogen supplied to the anode electrode according to the temperature. A technique for limiting the output from is disclosed.
JP 2003-36871 A JP 2000-106206 A

  By the way, the amount of power that can be extracted from the fuel cell without causing problems such as a sudden drop in output voltage depends on the condition of the fuel cell and the state of performance degradation. Even in the same case, it has been found that a fuel cell with insufficient conditioning and a fuel cell whose performance is beginning to deteriorate have a lower amount of power that can be taken out than those with good performance. Here, the conditioning of the fuel cell refers to the familiarity of the fuel cell with respect to hydrogen, air, other supply fluids, and the like. Therefore, although the fuel cell that has been actually used is not sufficiently conditioned, the fuel cell is well conditioned by taking out the power from the fuel cell after repeated use to some extent. In addition, as long as the fuel cell is used in an appropriate state, the deterioration in performance occurs due to a factor over time.If power is repeatedly extracted from the fuel cell and the number of times of use increases, the performance deterioration occurs at a certain stage. Will start.

  However, in the above-described conventional technology, the output is limited by paying attention only to the amount of hydrogen supplied to the fuel cell, the operating temperature of the fuel cell, etc. without considering the condition of the fuel cell and the state of performance degradation at all. Therefore, there is a problem that optimal output restriction control cannot always be performed.

  In other words, in the conventional technique, an upper limit value (hereinafter referred to as an output limit value) is set for performing output restriction on the assumption that the fuel cell is in an optimum state in which the conditioning is sufficient and performance degradation has not started. In a fuel cell with insufficient conditioning or a fuel cell that is starting to deteriorate in performance, the output voltage may suddenly drop even when power is taken below the set output limit value, causing the fuel cell to become overloaded. There is concern that it will lead to deterioration. In order to avoid this, it may be possible to set the output limit value on the premise of a fuel cell with insufficient conditioning or a fuel cell that has begun to deteriorate in performance. In this case, however, the conditioning is sufficient and the performance deteriorates. In the case of a fuel cell that is not provided, the output is limited to a value lower than the output that can be taken out originally, and there is a problem that efficient electric power cannot be taken out.

  The present invention was devised in view of the above-described conventional circumstances, and performs optimal output restriction control that also takes into account the state of fuel cell conditioning and the state of performance degradation, thereby overloading the fuel cell. An object of the present invention is to provide a fuel cell system capable of appropriately taking out electric power without entering a state.

  A fuel cell system according to the present invention includes a fuel cell that generates power by supplying fuel gas and oxidant gas, and a fuel cell output that limits output from the fuel cell when the operating temperature of the fuel cell is within a predetermined temperature range. Limiting means. In the fuel cell system having such a configuration, in the present invention, in order to achieve the above object, the fuel cell output limiting means is the integrated value of the operating temperature of the fuel cell and the amount of power taken out from the fuel cell in the past. Based on the integrated power, an output limit value that is an upper limit value of the output taken out from the fuel cell is determined.

  In addition, another fuel cell system according to the present invention includes a fuel cell that generates power by supplying fuel gas and oxidant gas, and a plurality of conditions including an integrated power that is an integrated value of the amount of power extracted from the fuel cell in the past. And a fuel cell output limiting means for limiting the output from the fuel cell. Then, the fuel cell output limiting means obtains a value that is a candidate of an output limit value that is an upper limit value of the output to be taken out from the fuel cell for each of a plurality of conditions, and most of the values that are candidates for the plurality of conditions. A low value is determined as the output upper limit value.

  As described above, the conditioning of the fuel cell is improved by taking out the power from the fuel cell after repeated use to some extent. In addition, the performance degradation of the fuel cell starts when the power extraction from the fuel cell is repeated and reaches a certain stage. Therefore, it is possible to estimate the state of fuel cell conditioning or performance degradation based on integrated power, which is an integrated value of the amount of power extracted from the fuel cell in the past.

  In the fuel cell system of the present invention, when the fuel cell output limiting means limits the output of the fuel cell, the integrated power of the fuel cell is also used as a parameter to determine the output limit value that is the upper limit value of the output taken out from the fuel cell. As a result, it is possible to perform optimum output restriction control in consideration of the condition of the fuel cell and the state of performance degradation.

  According to the fuel cell system of the present invention, the optimum output restriction control is performed in consideration of the condition of the fuel cell and the state of performance degradation, and the electric power is appropriately extracted without putting the fuel cell into an overload state. Can do.

  Hereinafter, specific embodiments of a fuel cell system according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 shows a schematic configuration of the fuel cell system of the present embodiment. As shown in FIG. 1, the fuel cell system of the present embodiment supplies a fuel cell 1 that generates power by supplying hydrogen as a fuel gas and air as an oxidant gas, and supplies hydrogen as a fuel gas to the fuel cell 1. A hydrogen supply device 2, an air supply device 3 for supplying air as an oxidant gas to the fuel cell 1, a cooling water supply device 4 for supplying cooling water for temperature adjustment to the fuel cell 1, and Is provided.

  The fuel cell 1 has a structure in which a power generation cell in which an anode electrode to which hydrogen is supplied and a cathode electrode to which air is supplied is overlapped with an electrolyte / electrode catalyst composite interposed therebetween is stacked in a multistage manner. It converts chemical energy into electrical energy. At the anode electrode of each power generation cell, hydrogen ions and electrons are dissociated when hydrogen is supplied, the hydrogen ions pass through the electrolyte, the electrons generate power through an external circuit, and move to the cathode electrode side. To do. Further, at the cathode electrode, oxygen in the supplied air reacts with the hydrogen ions and electrons to generate water, which is discharged to the outside.

  As the electrolyte of the fuel cell 1, for example, a solid polymer electrolyte is used in consideration of high energy density, low cost, light weight, and the like. The solid polymer electrolyte is made of an ion (proton) conductive polymer film such as a fluororesin ion exchange membrane, and functions as an ion conductive electrolyte when saturated with water.

  Although not shown in detail in the hydrogen supply device 2, for example, the hydrogen stored in a hydrogen storage means such as a hydrogen tank is extracted under reduced pressure, adjusted to a desired pressure and flow rate, and then the anode side of the fuel cell 1 It is the composition which supplies to.

  Although not shown in detail in the air supply device 3, for example, the outside air at a desired flow rate is taken in by driving a compressor or the like, cleaned by a filter, adjusted to a desired pressure, and then on the cathode electrode side of the fuel cell 1. It is the composition which supplies to.

  Although the detailed illustration of the cooling water supply device 4 is omitted, for example, the cooling water stored in the water tank is sucked by the cooling water pump and supplied to the fuel cell 1. The cooling water discharged from the fuel cell 1 is collected in a water tank.

  Further, in the fuel cell system of the present embodiment, the fuel cell 1 is connected to a load such as a motor or auxiliary equipment via the transformer 5, and the electric power obtained by the power generation in the fuel cell 1 is the control device 6. After being boosted by the transformer 5 under the control of the above, it is supplied to a load such as a motor or auxiliary equipment.

  Further, in the fuel cell system of the present embodiment, a temperature sensor 7 and a current sensor 8 and a voltage sensor 9 are respectively installed near the coolant outlet of the fuel cell 1 and between the fuel cell 1 and the transformer 5. The detection value by each sensor is input to the control device 6.

  The control device 6 controls the operation of the entire fuel cell system according to this embodiment. Specifically, for example, the control device 6 determines the operating temperature of the fuel cell 1 based on the coolant outlet temperature of the fuel cell 1 detected by the temperature sensor 7 so that the operating temperature becomes an appropriate temperature. The temperature control of the fuel cell 1 is performed. Further, the control device 6 performs power management of the fuel cell 1 by monitoring the amount of power extracted from the fuel cell 1 based on the detection values of the current sensor 8 and the voltage sensor 9. As a part of this power management, the control device 6 takes out the high output from the fuel cell 1 suddenly when the power required by a load such as a motor or auxiliary equipment suddenly increases. Control is performed to limit the output from the fuel cell 1 during a transient response so as not to cause inconvenience such as a sudden drop in the output voltage. That is, in the fuel cell system of the present embodiment, the control device 6 has a function as a fuel cell output limiting unit that limits the output from the fuel cell 1.

  In particular, in the fuel cell system of the present embodiment, when the control device 6 performs output restriction control for restricting the output from the fuel cell 1, it is an integrated value of the amount of power taken out from the fuel cell 1 in the past. The integrated power is also used as a parameter to determine a value for performing output restriction, that is, an output restriction value that is an upper limit value of output taken out from the fuel cell 1.

  Hereinafter, the output restriction control of the fuel cell 1 executed by the control device 6 will be described in detail with specific examples.

  Immediately after starting up the fuel cell system, if an attempt is made to transiently extract output from the fuel cell 1 with the operating temperature of the fuel cell 1 being as low as the atmospheric temperature, the output voltage of the fuel cell 1 rapidly drops, and FIG. As shown in FIG. 4, the voltage value (cell voltage) in each power generation cell during power generation may be lower than the lower limit (for example, 0.5 V / cell). When the cell voltage of the fuel cell 1 is lower than the lower limit as described above, protons are deficient in the solid polymer electrolyte membrane in the fuel cell 1 and the fuel cell 1 is overloaded, and the solid Since the polymer membrane constituting the polymer electrolyte membrane is also damaged, the fuel cell 1 is deteriorated. Therefore, the control device 6 uses the above-described operating temperature of the fuel cell 1 as a parameter, and the output upper limit value (output limit value) that can be taken out from the fuel cell 1 without causing a sudden drop in the output voltage of the fuel cell 1. ) And the output taken out from the fuel cell 1 is limited based on the output limit value.

  By the way, the sudden drop of the output voltage that causes the deterioration of the fuel cell 1 as described above is in a state where the conditioning of the fuel cell 1 is insufficient, or the performance of the fuel cell 1 is being deteriorated. This is particularly noticeable. Therefore, if the output limit value is determined on the assumption that the fuel cell 1 is in an optimal state in which the conditioning is sufficient and the performance has not started to deteriorate, and the output limit control for the fuel cell 1 is performed based on this, the conditioning is performed. However, in the fuel cell 1 in which the performance is insufficient or the performance of the fuel cell 1 is starting to deteriorate, the output voltage may be rapidly decreased even when the power is taken below the output limit value, and the fuel cell 1 may be deteriorated.

  Here, the conditioning of the fuel cell 1 is improved by taking out the electric power from the fuel cell 1 after repeated use to some extent, and the performance degradation of the fuel cell 1 is repeatedly taken out of the electric power from the fuel cell 1. Since it starts when it reaches a certain stage, the condition of the fuel cell 1 and the state of performance degradation should be estimated based on the integrated power that is the integrated value of the amount of power extracted from the fuel cell 1 in the past. Is possible. Therefore, in the fuel cell system of the present embodiment, the control device 6 determines the output limit value using the integrated power extracted from the fuel cell 1 as a parameter in addition to the operating temperature of the fuel cell 1 and the like, and based on this. Thus, output restriction control for the fuel cell 1 is performed.

  Specifically, in the fuel cell system of the present embodiment, as shown in FIG. 1, an integrated power recording device 10 is provided in the system, and the control device 6 uses the detection values of the current sensor 8 and the voltage sensor 9. The amount of power extracted from the fuel cell 1 is calculated, and the result is recorded in the integrated power recording device 10 as needed. When performing output restriction control on the fuel cell 1, the control device 6 reads the integrated power at that time from the integrated power recording device 10, and determines the operating temperature of the fuel cell 1 from the detection value of the temperature sensor 7. For example, the output limit value is determined by referring to an output limit table as shown in FIG. 3, for example, and the output of the fuel cell 1 calculated from the detection values of the current sensor 8 and the voltage sensor 9 indicates the output limit value. The power supply from the fuel cell 1 to the transformer 5 is controlled so as not to exceed.

  Here, the output restriction table shown in FIG. 3 is created by conducting an experiment or the like in advance, and the integrated power taken out from the fuel cell 1 is not less than a first predetermined value W1 (for example, 100,000 kW) and When it is less than the second predetermined value W2 (for example, 10 million kW) (hereinafter referred to as pattern 1), the integrated power taken out from the fuel cell 1 is less than the first predetermined value W1 or greater than or equal to the second predetermined value W2. In this case (hereinafter, referred to as pattern 2), different output limit values are described for each operating temperature of the fuel cell 1. Pattern 1 is a case where the conditioning of the fuel cell 1 is sufficient and it is presumed that the performance degradation of the fuel cell 1 has not started, and the pattern 2 is an insufficient conditioning of the fuel cell 1 or the fuel cell 1 Is estimated to have started to degrade. Therefore, in this output restriction table, even when the operating temperature of the fuel cell 1 is the same, the lower value is specified as the output restriction value in the case of the pattern 2 than in the case of the pattern 1. By determining the output limit value with reference to this output limit table, it is possible to perform optimal output limit control in consideration of the condition of the fuel cell 1 and the state of performance degradation.

  Since the value of the integrated power that can be a reference for estimating the condition of the conditioning and performance degradation of the fuel cell 1 varies depending on the specifications of the fuel cell 1 and the like, the first predetermined value W1 and the second predetermined value W2 described above. May be set as appropriate according to the specifications of the fuel cell 1 employed in the fuel cell system.

  Next, in the fuel cell system of the present embodiment, an example of control executed by the control device 6 when performing output restriction on the fuel cell 1 will be specifically described with reference to FIG.

  When the fuel cell system is activated, first, an activation operation is started in step S1, and supply of fluids such as hydrogen, air, and cooling water to the fuel cell 1 is started. When the fuel cell system reaches an idle state in which normal control is possible, the operation shifts from the startup operation to the normal operation (step S2).

  During normal operation, an output extraction instruction is input to the control device 6 in accordance with the amount of power required by a load such as a motor or auxiliary equipment (step S3). When the output take-out instruction is input, the control device 6 first determines the operating temperature of the fuel cell 1 from the detection value of the temperature sensor 7 in step S4, and in step S5, the operating temperature of the fuel cell 1 is subjected to output restriction control. Determine whether the temperature is within the required temperature range. If it is determined that the operating temperature of the fuel cell 1 is in a temperature range where output restriction control is required, the process proceeds to step S6. If it is determined that the output temperature is not required, the process proceeds to step S11. And migrate the process.

  In step S <b> 6, the control device 6 reads the integrated power at that time from the integrated power recording device 10, that is, the integrated power that is an integrated value of the amount of power extracted from the fuel cell 1 up to that time. Then, in step S7, it is determined whether or not the integrated power at that time is within the range of the above-mentioned first predetermined value W1 or more and less than the second predetermined value W2.

  As a result, when the integrated power is greater than or equal to the first predetermined value W1 and less than the second predetermined value W2, the control device 6 refers to the output restriction table as shown in FIG. 3 in step S8. Then, the output limit value corresponding to the operating temperature of the fuel cell 1 in the case of the pattern 1 described above is read out. On the other hand, when the integrated power is less than the first predetermined value W1 or greater than or equal to the second predetermined value W2, in step S9, referring to the output restriction table as shown in FIG. In this case, the output limit value corresponding to the operating temperature of the fuel cell 1 is read out. In step S10, the output limit value read in step S8 or step S9 is determined as the upper limit value of the output taken out from the fuel cell 1.

  Next, in step S11, the control device 6 instructs the transformer 5 to take out the output from the fuel cell 1 within a range in which the output from the fuel cell 1 does not exceed the output limit value determined in step S10. In step S12, the transformer 5 extracts power from the fuel cell 1 in accordance with an instruction from the control device 6, boosts the extracted power, and supplies the boosted power to a load such as a motor or auxiliary equipment.

  As described above, in the fuel cell system according to the present embodiment, when the control device 6 performs the output restriction control of the fuel cell 1, the fuel cell 1 is taken out from the fuel cell 1 in the past in addition to the operating temperature of the fuel cell 1. Since the output limit value is determined using the integrated power, which is the integrated value of the electric energy, as a parameter, and the output limit control for the fuel cell 1 is performed based on the output limit value, the fuel cell 1 is in a state of conditioning or performance degradation. Therefore, it is possible to appropriately take out electric power without making the fuel cell 1 in an overload state by performing optimal output restriction control in consideration of the above.

  Further, an output limit table as shown in FIG. 3 for determining the output limit value is created in advance, and the control device 3 determines the output limit value by referring to this output limit table. The processing load on the control device 3 can be greatly reduced. Further, a first predetermined value W1 that is a reference for estimating the conditioning state of the fuel cell 1 and a second predetermined value W2 that is a reference for estimating the performance degradation of the fuel cell 1 are determined, and the output restriction table is set. When the integrated power is greater than or equal to the first predetermined value W1 and less than the second predetermined value W2 (pattern 1), the accumulated power is less than the first predetermined value W1 or greater than or equal to the second predetermined value W2. In the case (pattern 2), the output limit value having a different value is described for each operating temperature of the fuel cell 1, so that the amount of information necessary for the output limit table is significantly reduced, and the fuel cell It is possible to determine an output limit value that appropriately reflects the condition of 1 conditioning or performance degradation, and it is possible to perform an optimal output limit.

  Further, the integrated power of the fuel cell 1 is recorded in the integrated power recording device 10, and the integrated power is read from the integrated power recording device 10 as necessary, whereby the value of the integrated power of the fuel cell 1 is obtained. Can be determined with high accuracy, and the optimum output can be limited accordingly.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. The fuel cell system of this embodiment has the same basic configuration as that of the first embodiment described above, and the first method is to determine the output limit value when the control device 6 performs the output limit control of the fuel cell 1. It is different from the form. Hereinafter, detailed description of the same parts as those in the first embodiment will be omitted, and processing contents in the control device 6 characteristic of the present embodiment will be described.

  In the fuel cell system of the present embodiment, when the control device 6 performs the output restriction control of the fuel cell 1, the output is performed for each of a plurality of conditions including integrated power that is an integrated value of the amount of power taken out from the fuel cell 1 in the past. Each value that is a candidate for the limit value is obtained, and the lowest value among the values that are candidates for the plurality of conditions is determined as the output limit value.

  A specific example will be described. For example, when the output limit value is determined based on three conditions of the operating temperature, the integrated power, and the operating pressure of the fuel cell 1, the control device 6 detects the temperature sensor 7. The operating temperature of the fuel cell 1 is determined from the value, and the integrated power at that time is read from the integrated power recording device 10. Although not shown, a pressure sensor is provided in the vicinity of the fuel cell inlet of the hydrogen supply device 2 or in the vicinity of the fuel cell inlet of the air supply device 3, and the operating pressure of the fuel cell 1 is determined from the detected value of this pressure sensor. To do.

  And the control apparatus 6 calculates | requires the candidate of the output limiting value for every condition with reference to the output limiting table as shown, for example in FIG. The lowest value is determined as the output limit value. Note that the output restriction table in FIG. 5A describes candidate values of output restriction values corresponding to the operating temperature of the fuel cell 1, and the output restriction table in FIG. 5B is an output corresponding to the integrated power. The limit value candidate values are described, and the output limit table in FIG. 5C describes the output limit value candidate values corresponding to the operating pressure of the fuel cell 1.

  For example, when it is determined that the operating temperature of the fuel cell 1 is 60 (deg.c), the integrated power is 10000000 (kW), and the operating pressure of the fuel cell 1 is 150 (kPa_a), 5, 80 kW is obtained from the output restriction table in FIG. 5A, 40 kW is obtained from the output restriction table in FIG. 5B, and 60 kW is obtained from the output restriction table in FIG. 5C. The lowest value among them, that is, 40 kW, is determined as the output limit value.

  When the output limit value is determined as described above, the control device 6 controls the transformer 5 within a range in which the output from the fuel cell 1 does not exceed the determined output limit value, as in the first embodiment. The output of the fuel cell 1 is instructed. Then, the transformer 5 extracts electric power from the fuel cell 1 in accordance with an instruction from the control device 6, boosts the extracted electric power, and supplies it to a load such as a motor or auxiliary machinery.

  As described above, also in the fuel cell system of the present embodiment, when the control device 6 performs the output restriction control of the fuel cell 1, the integrated power that is an integrated value of the amount of power extracted from the fuel cell 1 in the past is also obtained. Since the output limit value is determined using the parameter, and the output limit control is performed on the fuel cell 1 based on this value, the conditioning and performance degradation of the fuel cell 1 are reduced as in the first embodiment described above. By performing optimal output restriction control in consideration of the state, it is possible to appropriately extract electric power without putting the fuel cell 1 into an overload state.

  Further, in the fuel cell system of the present embodiment, the control device 6 obtains values that are candidates for the output limit value for each of a plurality of conditions, and sets the lowest value among the candidate values for each of the plurality of conditions as the output limit value. Therefore, the optimum output limit value can be determined efficiently under various operating conditions.

  Further, an output restriction table in which candidate values of output restriction values as shown in FIGS. 5A to 5C are prepared in advance for each condition, and the control device 3 refers to these output restriction tables. Thus, by obtaining the candidate value of the output limit value for each condition, the processing load of the control device 3 can be greatly reduced, and the addition and deletion of conditions to be considered as parameters can be flexibly handled It becomes possible to do.

It is a figure which shows schematic structure of the fuel cell system to which this invention is applied. It is a figure which shows the relationship between the cell voltage fall and deterioration of a fuel cell. It is a figure which shows an example of the output limitation table for determining an output limitation value. It is a flowchart which shows an example of the control performed by a control apparatus when performing the output restriction | limiting with respect to a fuel cell. It is a figure which shows an example of the output limitation table for calculating | requiring the candidate value of an output limitation value for every condition, (a) is the output limitation table which described the candidate value of the output limitation value corresponding to the driving | running temperature of a fuel cell, (B) is an output limit table in which candidate values of output limit values corresponding to the integrated power are described, and (c) is an output limit table in which candidate values of output limit values corresponding to the operating pressure of the fuel cell are described. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Hydrogen supply apparatus 3 Air supply apparatus 4 Cooling water supply apparatus 5 Transformer 6 Control apparatus 7 Temperature sensor 8 Current sensor 9 Voltage sensor 10 Integrated electric power recording apparatus

Claims (5)

A fuel cell that generates electricity by supplying fuel gas and oxidant gas;
A fuel cell output limiting means for limiting output from the fuel cell when the operating temperature of the fuel cell is in a predetermined temperature range;
Output that is the upper limit value of the output that the fuel cell output limiting means takes out from the fuel cell based on the operating temperature of the fuel cell and the integrated power that is the integrated value of the amount of power extracted from the fuel cell in the past A fuel cell system characterized by determining a limit value.   The fuel cell output limiting means has a first predetermined value when the integrated power is less than a first predetermined value or greater than or equal to a second predetermined value (provided that the first predetermined value <the second predetermined value). 2. The fuel cell system according to claim 1, wherein the output limit value is determined to be a low value as compared with the case where the value is less than the second predetermined value. Output limits of different values depending on whether the integrated power is less than the first predetermined value or greater than the second predetermined value and when the accumulated power is greater than or equal to the first predetermined value and less than the second predetermined value. An output limit table in which values are described for each operating temperature of the fuel cell;
3. The fuel cell output limiting means determines an output limit value according to an operating temperature of the fuel cell and an integrated power of the fuel cell with reference to the output limit table. Fuel cell system. An integrated power recording means for recording the integrated power of the fuel cell as needed;
4. The fuel cell according to claim 1, wherein the fuel cell output limiting unit reads the integrated power of the fuel cell from the integrated power recording unit when determining the output limit value. 5. system. A fuel cell that generates electricity by supplying fuel gas and oxidant gas;
Fuel cell output limiting means for limiting the output from the fuel cell according to a plurality of conditions including an integrated power that is an integrated value of the amount of power taken out from the fuel cell in the past,
The fuel cell output limiting means obtains a value that is a candidate for an output limit value that is an upper limit value of output to be taken out from the fuel cell for each of the plurality of conditions, and among the values that are candidates for each of the plurality of conditions A fuel cell system, wherein the lowest value is determined as the output upper limit value.

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