Fuel cell system

Abstract

A fuel cell system (100) according to the present disclosure comprises a plurality of fuel cell units (10), and a control device (20) that controls the plurality of fuel cell units (10). The control device (20) predicts a designed end-of-life arrival time for each of the plurality of fuel cell units (10), orders the plurality of fuel cell units (10) in order starting from that nearest to the designed end-of-life arrival time from the day when the prediction was performed, and determines the aforementioned order as a replacement priority order for the plurality of fuel cell units (10).

Description

fuel cell system

[0001] The present disclosure relates to fuel cell systems.

[0002] A fuel cell system equipped with multiple fuel cell units has been proposed as a configuration for obtaining a high amount of power generation. Patent Document 1 discloses a fuel cell system equipped with multiple fuel cells. In the fuel cell system of Patent Document 1, in order to prevent some of the multiple fuel cells from deteriorating faster than the other fuel cells, the fuel cell to be stopped or started is determined based on the number of times each fuel cell is started. Note that the fuel cells in Patent Document 1 correspond to fuel cell units.

[0003] JP 2023-47079 A

[0004] The present disclosure provides a technology suitable for using all fuel cell units constituting a fuel cell system having a plurality of fuel cell units until close to the end of their designed lifespan.

[0005] The fuel cell system of the present disclosure is a fuel cell system comprising a plurality of fuel cell units and a control device that controls the plurality of fuel cell units, wherein the control device predicts the end of the design life of each of the plurality of fuel cell units, ranks the plurality of fuel cell units in order of the closest to the end of the design life from the date the prediction is made, and determines the rank as the replacement priority of the plurality of fuel cell units.

[0006] The technology according to the present disclosure is suitable for a fuel cell system having a plurality of fuel cell units, in which all of the fuel cell units constituting the system are used until close to the end of their designed lifespan.

[0007] 1 is a block diagram showing an example of a fuel cell system according to an embodiment; FIG. 2 is a block diagram showing an example of a fuel cell unit constituting the fuel cell system shown in FIG. 1; FIG. 3 is a diagram showing an example of a list of replacement priorities for fuel cell units determined by a control device of the fuel cell system according to an embodiment; FIG. 4 is a flowchart for predicting the end of the design life of a fuel cell unit; FIG. 5 is a diagram showing an example of a graph used to predict the end of the design life; and FIG. 6 is a diagram showing an example of a method for determining the replacement date for each of the multiple fuel cell units constituting the fuel cell system.

[0008] (Knowledge, etc. that forms the basis of the present disclosure) As described in the "Background Art" section, Patent Document 1 discloses a fuel cell system that determines which fuel cell units to stop or start operation based on the number of times each fuel cell unit is started, in order to prevent some of the fuel cell units from deteriorating faster than the other fuel cell units. The fuel cell system disclosed in Patent Document 1 prevents some of the fuel cell units from deteriorating faster than the other fuel cells, making it possible to roughly align the design lifespans of all of the fuel cell units that make up the system.

[0009] That is, in the fuel cell system disclosed in Patent Document 1, the designed life spans of all fuel cell units reach the end of their life at approximately the same time. Also, in the fuel cell system disclosed in Patent Document 1, there is no difference in the number of startups of the multiple fuel cell units, making it difficult for the user to predict which fuel cell unit will reach the end of its designed life span sooner.

[0010] In a fuel cell system equipped with multiple fuel cell units, it is desirable to replace fuel cell units well into their design life to prevent a situation in which a fuel cell unit reaches the end of its design life and is unable to generate power and thus unable to keep up with the required power output. However, in the fuel cell system disclosed in Patent Document 1, it is not known which fuel cell unit will reach the end of its design life sooner or which fuel cell unit should be replaced first, so replacement begins by randomly selecting a fuel cell unit. Therefore, in such conventional fuel cell systems, it is difficult to maximize lifetime power generation by using the fuel cell units that make up the system as close to their design life as possible.

[0011] Therefore, the present inventors have investigated a technology suitable for using all of the fuel cell units that make up a fuel cell system equipped with a plurality of fuel cell units until close to the end of their designed lifespan.

[0012] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

[0013] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0014] (Embodiment) Hereinafter, an embodiment will be described with reference to Figs.

[0015] [1-1. Configuration] Fig. 1 is a configuration diagram showing an example of a fuel cell system according to Embodiment 1. As shown in Fig. 1, the fuel cell system 100 includes a plurality of fuel cell units 10 and a control device 20. The control device 20 controls the plurality of fuel cell units 10. Electric power generated and output by the fuel cell system 100 is supplied to a load 200.

[0016] In the example shown in Figure 1, the fuel cell system 100 includes N fuel cell units 10, where N is an integer equal to or greater than 2. In Figure 1, the N fuel cell units 10 are a first fuel cell unit 10, a second fuel cell unit 10, a third fuel cell unit 10, ..., and an (N-1)th fuel cell unit 10. N-1 , Nth fuel cell unit 10 N It is expressed as follows.

[0017] The load 200 may be a factory, a hospital, a school, a commercial facility, an office building, or the like.

[0018] FIG. 2 is a diagram showing an example of the configuration of the fuel cell unit 10 that constitutes the fuel cell system 100 shown in FIG.

[0019] The fuel cell unit 10 includes, for example, a fuel cell stack 11, a DCDC converter 12, a DC / DC inverter 13, and a control unit 14. Examples of fuel cells include a polymer electrolyte fuel cell, a solid oxide fuel cell, a phosphoric acid fuel cell, and a molten carbonate fuel cell. A fuel cell stack 11 is supplied with a fuel gas and an oxidant gas. Electric power is generated as a result of a reaction between the fuel gas and the oxidant gas in the fuel cell stack 11, and the DC power is output to the outside of the fuel cell stack 11. The DCDC converter 12 converts the DC power output from the fuel cell stack 11 into DC power of a desired voltage. The DC / DC inverter 13 converts the DC power output from the DCDC converter 12 into AC power suitable for supplying power to the outside of the fuel cell unit 10. The AC power is supplied to a load 200, for example, via an electrical path external to the fuel cell system 100.

[0020] The control unit 14 is connected to the control device 20 via a wired or wireless connection so as to be able to communicate with the control device 20. For example, the control unit 14 performs control necessary for the operation of the fuel cell unit 10 in accordance with a control signal received from the control device 20. For example, the control unit 14 controls the operation of the DCDC converter 12, the DC / AC inverter 13, auxiliary equipment (not shown), etc. Examples of auxiliary equipment include a pump, a blower, and a valve. The pump and blower send fuel gas and oxidant gas to the fuel cell stack 11, for example. The control unit 14 transmits, to the control device 20, data indicating the power generated in the fuel cell system 100, data indicating the cumulative number of startups of the fuel cell unit 10, data indicating the cumulative startup time of the fuel cell unit 10, etc. The data indicating the power generated may be, for example, data indicating the magnitude of the current output from the fuel cell unit 10. The data indicating the cumulative number of startups of the fuel cell unit 10 is obtained, for example, by counting the cumulative number of times a switch (not shown) of the fuel cell unit 10 provided in the fuel cell unit 10 has been switched from OFF to ON. The data indicating the accumulated startup time of the fuel cell unit 10 is obtained, for example, by counting the accumulated time that a switch (not shown) of the fuel cell unit 10 provided in the fuel cell unit 10 has been in the ON state. The control unit 14 is, for example, a computer equipped with a storage device that stores programs necessary for operating the fuel cell unit 10, and a processor that reads and executes the programs from the storage device.

[0021] The fuel used in the fuel cell unit 10 is, for example, pure hydrogen. In this case, the fuel cell system 100 further includes a tank (not shown) in which pure hydrogen is stored. Hydrogen gas is supplied as fuel gas from this tank to the fuel cell stack 11. The fuel used in the fuel cell system 100 may contain hydrocarbon gas such as methane gas, propane gas, or butane gas. In this case, the fuel cell system 100 includes a reformer. A hydrogen-containing gas is produced as fuel gas from the hydrocarbon gas in the reformer, and the hydrogen-containing gas is supplied to the fuel cell stack 11. Examples of fuels containing hydrocarbon gas include city gas and LP gas.

[0022] As described above, the control device 20 controls the multiple fuel cell units 10. The control device 20 is, for example, a computer equipped with a storage device that stores programs necessary for control, and a processor that reads and executes the programs from the storage device. The control device 20 may be provided near the fuel cell units 10, or may be provided in a location remote from the fuel cell units 10. The functions of the control device 20 may be provided by a cloud server or an edge server.

[0023] In accordance with instructions from the control device 20, the control unit 14 of each fuel cell unit 10 controls the DCDC converter 12 and the DC / AC inverter 13. In accordance with instructions from the control device 20, the control unit 14 of each fuel cell unit 10 controls auxiliary equipment such as a blower and a pump so that power is generated in the fuel cell unit 10.

[0024] The control device 20 can obtain, for example, data indicating the power generated by the fuel cell unit 10, data indicating the cumulative number of times the fuel cell unit 10 has been started, data indicating the cumulative start-up time of the fuel cell unit 10, etc. from the control unit 14 of each fuel cell unit 10. In this way, the control device 20 can obtain information about each of the multiple fuel cell units 10 for each fuel cell unit 10.

[0025] The maximum output of the fuel cell system 100 can be freely designed by increasing or decreasing the number of fuel cell units 10. Each fuel cell unit 10 can be operated independently of the others.

[0026] [1-2. Operation] An example of the operation of the fuel cell system 100 configured as above will now be described.

[0027] The control device 20 acquires information indicating the required power from an external source. The information indicating the required power may be information provided to the control device 20 from a higher-level control device, or may be information input from a terminal by an administrator of the fuel cell system 100. For example, assume that the required power is 500 kW. The control device 20 activates a number of fuel cell units 10 capable of generating 500 kW of power. The method for selecting the fuel cell units 10 to be activated is not particularly limited. For example, the fuel cell units 10 to be activated are determined according to a preset operating method in the fuel cell system 100. There are many combinations of fuel cell units 10 to be activated.

[0028] The control device 20 predicts the end of the design life of each of the multiple fuel cell units 10, ranks the multiple fuel cell units 10 in order of the closest time to the end of the design life from the date the prediction was made, and determines the ranking as the replacement priority of the multiple fuel cell units 10.

[0029] Here, the design life end time is the month, week, or day of the design life end. That is, the fuel cell system 100 of this embodiment can predict the end of the design life of each fuel cell unit 10 on a monthly, weekly, or daily basis. For example, the user can set whether the end of the design life is to be predicted on a monthly, weekly, or daily basis.

[0030] In a fuel cell system equipped with multiple fuel cell units, such as the fuel cell system 100 of the present embodiment, it is desirable to replace the fuel cell units well into their design life to prevent the fuel cell units from becoming unable to generate power due to the end of their design life and being unable to keep up with the required power generation output. On the other hand, it is also desirable to maximize the lifetime power generation of each fuel cell unit by using them to the fullest extent possible until close to the end of their design life. As described above, the fuel cell system 100 of the present embodiment can predict the end of the design life of each of the multiple fuel cell units 10 and determine the replacement priority for the multiple fuel cell units 10. This allows the user to determine the end of the design life of each of the multiple fuel cell units 10 and which of the multiple fuel cell units 10 has reached the end of its design life and should be replaced first. As a result, the user can replace the fuel cell units 10 based on the determined replacement priority, for example, by replacing the fuel cell units 10 with new ones in order of the determined replacement priority. As a result, the fuel cell system 100 of this embodiment can avoid the problem of the fuel cell units 10 becoming unable to generate power due to reaching the end of their design life and being unable to keep up with the required power output, while maximizing the use of all fuel cell units 10 that make up the fuel cell system 100 until close to the end of their design life, thereby increasing the lifetime power generation capacity. In this way, the fuel cell system 100 of this embodiment is suitable for using all fuel cells that make up the system until close to the end of their design life.

[0031] 3 shows an example of a list of replacement priorities for the fuel cell units 10, determined by the control device 20 of the fuel cell system 100 according to the embodiment. The control device 20 may be configured to display such a list using a computer application. Note that the list shown in FIG. 3 is an example in which the design life end time is the design life end date.

[0032] Below, we will explain the operation of the fuel cell system 100 of this embodiment using the example of the case where the design life end date is the design life end date, but the same applies when the design life end date is the next month or week after the design life end date.

[0033] The control device 20 can predict the design life end date, for example, as follows.

[0034] The control device 20 predicts the end of the design life of each of the fuel cell units 10, for example, based on the cumulative number of startups and cumulative power generation time of each of the fuel cell units 10. As described above, the control device 20 can acquire data on the cumulative number of startups and cumulative power generation time of each of the fuel cell units 10, for example, from the control unit 14 of each of the fuel cell units 10. In this way, when predicting the end of the design life of each fuel cell unit 10 using both the cumulative number of startups and the cumulative power generation time, it is possible to predict the end of the design life of each fuel cell unit 10 more accurately than when predicting based on only one of the cumulative number of startups or the cumulative power generation time. Therefore, the replacement priority of the fuel cell units 10, which is determined based on such accurate end of the design life, is also more accurate. As a result, the fuel cell system 100 of this embodiment can more reliably use all of the fuel cell units 10 constituting the fuel cell system 100 to their full potential close to their design life, thereby increasing the lifetime power generation amount.

[0035] The design life end date of the fuel cell unit 10 can be predicted using the cumulative number of startups and cumulative power generation time, for example, in the following procedure. Figure 4 is a flowchart for predicting the design life end date of the fuel cell unit 10. The control device 20 executes, for example, the processes shown in Figure 4.

[0036] The control device 20 acquires data on the cumulative number of startups and cumulative power generation time from each fuel cell unit 10 (S1).

[0037] Next, the control device 20 calculates the remaining life of each fuel cell unit 10 using the cumulative number of startups and cumulative power generation time (S2). The remaining life is calculated using the following formula (1). The design life number of startups is preset as the upper limit of the number of startups for each fuel cell unit 10. Similarly, the design life power generation time is preset as the upper limit of the power generation time for each fuel cell unit 10.

[0038] Remaining life = 1 - MAX {(cumulative number of starts) / (design life number of starts), (cumulative power generation time) / (design life power generation time)} (1)

[0039] Specifically, the control device 20 calculates (cumulative number of startups) / (design life number of startups) and (cumulative power generation time / design life power generation time) using data on the cumulative number of startups and cumulative power generation time acquired from each fuel cell unit 10. Next, the control device 20 calculates the remaining life by taking the larger of (cumulative number of startups) / (design life number of startups) and (cumulative power generation time / design life power generation time) as the value of MAX{(cumulative number of startups) / (design life number of startups), (cumulative power generation time) / (design life power generation time)} in the above formula (1). The remaining life is calculated for all fuel cell units 10 included in the fuel cell system 100.

[0040] The control device 20 uses the remaining life value newly calculated by the processing of steps S1 and S2 and the remaining life values ​​previously calculated and accumulated by the processing of steps S1 and S2 to interpolate the remaining life using, for example, functional approximation, and predicts the date on which the remaining life will become 0 (zero) as the design life end date (S3). Note that the interpolation of the remaining life using functional approximation may be, for example, linear interpolation or a quadratic function interpolation other than linear interpolation. Figure 5 shows an example of a graph used to predict the design life end date.

[0041] By the above processing of steps S1 to S3, the design life end date of each fuel cell unit 10 is predicted.

[0042] Although an example of a method for predicting the end of the design life of the fuel cell unit 10 has been described, the end of the design life of the fuel cell unit 10 may be predicted by other methods.

[0043] The control device 20 may determine the replacement start date for the fuel cell units 10 based on, for example, the replacement priority, the design life end date, and a daily replacement upper limit for the number of fuel cell units 10. By determining the replacement start date for the fuel cell units 10, the user can know when to start replacing the multiple fuel cell units 10 that make up the fuel cell system 100, making it easier to plan a schedule for replacing the fuel cell units 10. Furthermore, since the replacement priority and the design life end date are used to determine the replacement start date, the replacement start date can be set to a date that maximizes the use of all fuel cell units 10 that make up the fuel cell system 100 until close to the end of their design lives, thereby increasing the lifetime power generation capacity. Therefore, by starting the replacement of the fuel cell units 10 that make up the fuel cell system 100 from the replacement start date determined in this manner, the fuel cell system 100 of this embodiment can maximize the use of all fuel cell units 10 that make up the fuel cell system 100 until close to the end of their design lives, thereby increasing the lifetime power generation capacity.

[0044] Here, the upper limit of the number of fuel cell units 10 that can be replaced each day can be freely set by the user, for example. For example, the user may decide the number of fuel cell units 10 that can be replaced each day and set this as the upper limit of the number of replacements. It is also possible to set different upper limits of the number of replacements for each day of the week. For example, if fuel cell units 10 can only be replaced on Sundays, the user could set the upper limit of the number of replacements on Sundays to, for example, 10, and the upper limit of the number of replacements on other days of the week other than Sundays to 0.

[0045] An example of a method for determining the exchange start date is as follows.

[0046] The control device 20 determines the replacement date for each of the fuel cell units 10 that make up the fuel cell system 100, for example, using the predicted design life end date and the upper replacement limit number, in order from the fuel cell unit 10 with the highest replacement priority, or from the fuel cell unit 10 with the lowest replacement priority. The replacement start date is determined based on the replacement dates of the fuel cell units 10 that make up the fuel cell system 100. In other words, the replacement date of the fuel cell unit that is assigned the earliest replacement date among the fuel cell units 10 that make up the fuel cell system 100 is determined as the "replacement start date."

[0047] Fig. 6 is a diagram showing an example of a method for determining the replacement date for each of the multiple fuel cell units 10 that make up the fuel cell system 100. Fig. 6 shows an example of a method for determining the replacement date for the fuel cell unit 10 in order of replacement priority (i.e., the fuel cell unit 10 whose predicted design life end date is furthest from the present).

[0048] For example, the control device 20 creates a list of replacement priorities for the fuel cell units 10 determined by the control device 20, such as the list shown in Fig. 3. In this list, starting with the fuel cell unit 10 with the lowest replacement priority (i.e., the fuel cell unit 10 with the predicted design life end date furthest from the present), the replacement date for that fuel cell unit 10 is assigned to a day before the predicted design life end date on which the upper replacement limit number is not 0. If, when a replacement date is assigned, the total number of fuel cell units 10 assigned for that day exceeds the upper replacement limit number, the replacement date for that fuel cell unit 10 is assigned to a day before that day on which the upper replacement limit number is not 0.

[0049] When assigning replacement dates to each fuel cell unit 10, it is desirable to assign replacement dates to days on which the upper limit number of replacements is not 0, counting back one day from the day before the predicted end of the design life of the fuel cell unit 10. This allows the fuel cell unit 10 to be used until just before the predicted end of the design life of the fuel cell unit 10, thereby increasing the lifetime power generation capacity of the fuel cell unit 10. Note that even in this case, if the total number of fuel cell units 10 assigned on the assigned replacement date for that fuel cell unit 10 exceeds the upper limit number, the replacement date is determined by counting back another day.

[0050] The above process for determining the replacement date for each of the fuel cell units 10 constituting the fuel cell system 100 may be performed each time the design life end date is predicted. That is, the process for determining the replacement date may be performed after step S3 shown in FIG.

[0051] The timing for predicting the end of the design life of each fuel cell unit 10 and determining the replacement priority of the fuel cell units 10 based on the predicted end of the design life is not particularly limited. For example, it may be once a day, once a week, or once a month. For example, the processing of the flowchart shown in Figure 4 may be performed once a month to update the end of the design life, replacement priority, replacement date, and replacement start date for the fuel cell system 10 every month.

[0052] [1-3. Effects, etc.] As described above, in this embodiment, the fuel cell system 100 comprises a plurality of fuel cell units 10 and a control device 20 that controls the plurality of fuel cell units 10. The control device 20 predicts the end of the design life of each of the plurality of fuel cell units 10, ranks the plurality of fuel cell units 10 in order of those closest to the end of their design life from the date the prediction was made, and determines the ranks as the replacement priorities of the plurality of fuel cell units 10.

[0053] This allows the user to understand when the design life of each of the multiple fuel cell units 10 will end, and which of the multiple fuel cell units 10 will reach the end of their design life sooner and should be replaced first. As a result, by replacing fuel cell units 10 with new ones based on the determined replacement priority, the user can avoid the problem of a fuel cell unit 10 becoming unable to generate power due to the end of its design life and being unable to keep up with the required power generation output, while maximizing the use of all fuel cell units 10 that make up the fuel cell system 100 close to their design life, thereby increasing the lifetime power generation capacity. In this way, the fuel cell system 100 of this embodiment is suitable for using all of the fuel cells that make up the system close to their design life.

[0054] As in this embodiment, the control device 20 may predict the end of the design life based on the cumulative number of startups and cumulative power generation time of each of the plurality of fuel cell units 10 .

[0055] As a result, the fuel cell system 100 of this embodiment can more reliably maximize the use of all fuel cell units 10 that make up the fuel cell system 100 close to the end of their designed lifespan, thereby increasing the lifetime power generation capacity.

[0056] As in this embodiment, the design life end time may be the design life end date.

[0057] As a result, the fuel cell system 100 of this embodiment can more reliably maximize the use of all fuel cell units 10 that make up the fuel cell system 100 close to the end of their designed lifespan, thereby increasing the lifetime power generation capacity.

[0058] If the design life end time is the design life end date, as in this embodiment, the control device 20 may determine the start date for replacement of multiple fuel cell units 10 based on the replacement priority, the design life end date, and the maximum number of fuel cell units 10 that can be replaced each day.

[0059] As a result, the fuel cell system 100 of this embodiment can maximize the lifetime power generation by using all of the fuel cell units 10 that make up the fuel cell system 100 to the fullest extent possible, close to the end of their designed lives. Furthermore, the user can know when to start replacing the multiple fuel cell units 10 that make up the fuel cell system 100, making it easier to plan a schedule for replacing the fuel cell units 10.

[0060] If the design life end time is the design life end date, as in this embodiment, the control device 20 may determine the replacement date for each of the multiple fuel cell units 10 using the design life end date and the maximum replacement number, starting with the fuel cell unit 10 with the highest replacement priority, or starting with the fuel cell unit 10 with the lowest replacement priority, and may determine the replacement start date based on the replacement dates for the multiple fuel cell units 10.

[0061] This allows the fuel cell unit 10 to be used until just before the end of its predicted design life, thereby increasing the lifetime power generation capacity of the fuel cell unit 10.

[0062] Other Embodiments As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made.

[0063] In this embodiment, the determination of the replacement start timing for the fuel cell units 10 has been described in detail using an example in which the design life end date is the design life end date. However, the replacement start timing (i.e., the replacement start month or replacement start week) can also be determined in a similar manner when the design life end date is the month or week before the design life end date. For example, the control device 200 may determine the replacement start timing for multiple fuel cell units 10 based on the replacement priority, the design life end date, and a maximum number of fuel cell units 10 that can be replaced that is set for each period. Furthermore, in this case, the control device 20 determines the replacement timing for each of the multiple fuel cell units 10 using the design life end date and the maximum number of replacements, for example, in order from the fuel cell units 10 with the highest replacement priority or the fuel cell units 10 with the lowest replacement priority, and then determines the replacement start timing based on the replacement times of the multiple fuel cell units 10.

[0064] The fuel cell system 100 of the present disclosure may be used in conjunction with a solar power generation system. In a system in which a solar power generation system and a fuel cell system cooperate to supply power, the fuel cell system is typically operated to provide supplemental power when the amount of power generated by the solar power generation system is insufficient. Therefore, it is common for only the necessary number of fuel cell units 10 out of the multiple fuel cell units 10 to be started and operated, which can lead to differences in the cumulative number of start-ups and cumulative power generation time among the multiple fuel cell units 10. By applying the technology of the present disclosure to such a power supply system in which it is difficult to determine whether a fuel cell unit 10 needs to be replaced, the technology of the present disclosure can function effectively.

[0065] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0066] (Technology 1) A fuel cell system comprising: a plurality of fuel cell units; and a control device that controls the plurality of fuel cell units, wherein the control device predicts the end of the design life of each of the plurality of fuel cell units, ranks the plurality of fuel cell units in order of the closest to the end of the design life from the date the prediction is made, and determines the rank as the replacement priority of the plurality of fuel cell units.

[0067] (Technology 2) The fuel cell system according to Technology 1, wherein the control device predicts the end of the design life based on the cumulative number of startups and cumulative power generation time of each of the plurality of fuel cell units.

[0068] (Technology 3) The fuel cell system according to Technology 1 or 2, wherein the control device determines the timing for starting replacement of the plurality of fuel cell units based on the replacement priority, the end of the design life, and an upper limit number of replacements of the fuel cell units set for each period.

[0069] (Technology 4) A fuel cell system according to Technology 3, wherein the control device determines the replacement time for each of the plurality of fuel cell units using the design life end time and the upper replacement limit number, in order from the fuel cell unit with the highest replacement priority or the fuel cell unit with the lowest replacement priority, and determines the replacement start time based on the replacement times of the plurality of fuel cell units.

[0070] (Technology 5) The fuel cell system according to any one of Techniques 1 to 4, wherein the design life end time is a design life end date.

[0071] (Technology 6) The fuel cell system according to Technology 5, wherein the control device determines a replacement start date for the plurality of fuel cell units based on the replacement priority, the design life end date, and a maximum number of replacements for the fuel cell units set for each day.

[0072] (Technology 7) A fuel cell system according to Technology 6, wherein the control device determines the replacement date for each of the plurality of fuel cell units using the design life end date and the upper replacement limit number, in order from the fuel cell unit with the highest replacement priority or the fuel cell unit with the lowest replacement priority, and determines the replacement start date based on the replacement dates of the plurality of fuel cell units.

[0073] The technology disclosed herein is applicable to, for example, a system that supplies power by linking a solar power generation device, a fuel cell, and a storage battery. The technology disclosed herein is applicable to, for example, environmental protection initiatives such as RE100 (Renewable Energy 100%).

Claims

1. A fuel cell system comprising: a plurality of fuel cell units; and a control device that controls the plurality of fuel cell units, wherein the control device predicts the end of the design life of each of the plurality of fuel cell units, ranks the plurality of fuel cell units in order of those closest to the end of their design life from the date the prediction was made, and determines the ranking as the replacement priority order for the plurality of fuel cell units.

2. The fuel cell system according to claim 1, wherein said control device predicts the end of said designed life based on a cumulative number of startups and a cumulative power generation time of each of said plurality of fuel cell units.

3. The fuel cell system of claim 1, wherein the control device determines the start time for replacement of the plurality of fuel cell units based on the replacement priority order, the end of the design life, and a maximum number of fuel cell units to be replaced set for each period.

4. The fuel cell system of claim 3, wherein the control device determines the replacement time for each of the plurality of fuel cell units using the design life end time and the upper replacement limit number, in order from the fuel cell unit with the highest replacement priority or from the fuel cell unit with the lowest replacement priority, and determines the start time for replacement based on the replacement times of the plurality of fuel cell units.

5. The fuel cell system according to claim 1, wherein the design life end time is a design life end date.

6. The fuel cell system according to claim 5, wherein the control device determines a start date for replacement of the plurality of fuel cell units based on the replacement priority order, the design life end date, and a maximum number of replacements of the fuel cell units set for each day.

7. The fuel cell system of claim 6, wherein the control device determines the replacement date for each of the plurality of fuel cell units using the design life end date and the upper replacement limit number, in order from the fuel cell unit with the highest replacement priority or from the fuel cell unit with the lowest replacement priority, and determines the replacement start date based on the replacement dates for the plurality of fuel cell units.