Fuel cell system, method for operating fuel cell system, computer program, and recording medium

Abstract

In an operation plan (50) of the fuel cell system, a first stop time (ta1) is a time corresponding to a specific remaining time of the first fuel cell (5) and is a time for switching the first fuel cell (5) from a power generation state to a stop state, and for all natural numbers (J) satisfying 2 < = J < = N, a second stop time (ta2) is a time for switching the first fuel cell (5) from the power generation state to the stop state. A J-th stop time (taJ) is a time for switching the J-th fuel cell (5) from a power generation state to a stop state, is an earlier time among a time before a second predetermined time (T2) from a (J-1)-th stop time (ta (J-1)) and a time corresponding to a specific remaining time of the J-th fuel cell (5), and satisfies 1 < = J < = N for all natural numbers J satisfying 1 < = J < = N, the J-th start time (tbJ) is a time for switching the J-th fuel cell (5) from the stopped state to the power generation state, and is a time at which a first predetermined time (T1) has elapsed from the J-th stop time (taJ), and the operation plan (50) does not include a period during which more than R fuel cells (5) among the first to Nth fuel cells (5) are in the stopped state.

Description

Technical Field

[0001] The present disclosure relates to a fuel cell system, an operating method, a computer program, and a recording medium. Background Art

[0002] In a fuel cell system, control is performed such that the fuel cell stacks generating power are sequentially switched over time. For example, Patent Document 1 describes a fuel cell system that performs such control.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-018823 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present disclosure provides a technology suitable for ensuring the reliability of a fuel cell system and for continuously extracting electric power from the fuel cell system.

[0008] Solutions for solving problems

[0009] The present disclosure provides a fuel cell system comprising:

[0010] First to Nth fuel cells, the first to Nth fuel cells being specified with an initial value of a power-generating time and a first specified time, wherein N is a natural number greater than or equal to 2; and

[0011] a control device for controlling the first fuel cell to the Nth fuel cell,

[0012] The operating mode of the control device includes a specific operating mode. In the specific operating mode, the control device controls the first fuel cell to the Nth fuel cell according to the operating plan.

[0013] The operation plan includes the first stop time to the Nth stop time, and the first start time to the Nth start time,

[0014] When the remaining time of the power generation possible time at the start of the specific operation mode is defined as a specific remaining time,

[0015] The first stop time is a time corresponding to the specific remaining time of the first fuel cell and is a time for switching the first fuel cell from a power generation state to a stop state.

[0016] For all natural numbers J satisfying 2≤J≤N, the Jth stop time is a time for switching the Jth fuel cell from a power generation state to a stop state, and is the earlier of a time before the second predetermined time from the J-1th stop time and a time corresponding to the specific remaining time of the Jth fuel cell.

[0017] For all natural numbers J that satisfy 1≤J≤N, the Jth start-up time is the time for switching the Jth fuel cell from the stop state to the power generation state, and is the time when the first predetermined time has elapsed from the Jth stop time.

[0018] The operation plan does not include a period in which more than R fuel cells from the first to Nth fuel cells are in a stopped state, where R is a natural number greater than or equal to 1 and less than N.

[0019] On the other hand, the present disclosure provides an operating method of a fuel cell system, wherein the fuel cell system includes a first fuel cell to an Nth fuel cell for which an initial value of a power generation time and a first predetermined time are specified, wherein N is a natural number greater than or equal to 2, wherein:

[0020] The operating method includes controlling the first fuel cell to the Nth fuel cell according to an operating plan in a specific operating mode,

[0021] The operation plan includes the first stop time to the Nth stop time, and the first start time to the Nth start time,

[0022] When the remaining time of the power generation possible time at the start of the specific operation mode is defined as a specific remaining time,

[0023] The first stop time is a time corresponding to the specific remaining time of the first fuel cell and is a time for switching the first fuel cell from a power generation state to a stop state.

[0024] For all natural numbers J satisfying 2≤J≤N, the Jth stop time is a time for switching the Jth fuel cell from a power generation state to a stop state, and is the earlier of a time before the second predetermined time from the J-1th stop time and a time corresponding to the specific remaining time of the Jth fuel cell.

[0025] For all natural numbers J that satisfy 1≤J≤N, the Jth start-up time is the time for switching the Jth fuel cell from the stop state to the power generation state, and is the time when the first predetermined time has elapsed from the Jth stop time.

[0026] The operation plan does not include a period in which more than R fuel cells from the first to Nth fuel cells are in a stopped state, where R is a natural number greater than or equal to 1 and less than N.

[0027] Effects of the Invention

[0028] The technology disclosed herein is suitable for ensuring the reliability of a fuel cell system and for continuously extracting power from the fuel cell system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural diagram of a fuel cell system in an embodiment.

[0030] Figure 2 This is an explanatory diagram showing the number of transmission stations according to the first example.

[0031] Figure 3 This is an explanatory diagram of the operation plan involved in the first example.

[0032] Figure 4 This is an explanatory diagram of the frequency of switching any one of the first to Nth fuel cells from the power generation state to the stop state in the first example.

[0033] Figure 5 This is an explanatory diagram of the frequency of switching any one of the first to Nth fuel cells from the power generation state to the stop state in the second example.

[0034] Figure 6 This is a flowchart for explaining the creation of an operation plan in the embodiment. DETAILED DESCRIPTION

[0035] The following describes the embodiments in detail with reference to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or repeated descriptions of substantially the same structures may be omitted.

[0036] 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.

[0037] (Implementation Method)

[0038] Next, use Figures 1 to 6 The following describes an embodiment.

[0039] [1-1. Configuration of Fuel Cell System in Embodiment]

[0040] Figure 1This is a structural diagram of a fuel cell system 100 in an embodiment. Fuel cell system 100 includes multiple fuel cells 5, a hydrogen-containing gas supply path 6, an oxygen-containing gas supply path 7, a control device 8, and a power line 13. Multiple fuel cells 5 are connected in parallel to an external load 14 via power line 13. Load 14 is an electrical load that consumes power.

[0041] Each of the plurality of fuel cells 5 includes an electrolyte membrane 1, an anode 2, and a cathode 3. In the fuel cell 5, the electrolyte membrane 1 is arranged between the anode 2 and the cathode 3. A stack including the electrolyte membrane 1, the anode 2, and the cathode 3 is formed. Catalysts for promoting reactions that extract electrons are provided at the anode 2 and the cathode 3, respectively. The anode 2 is connected to a hydrogen-containing gas supply path 6. The cathode 3 is connected to an oxygen-containing gas supply path 7. Hydrogen-containing gas is supplied from a hydrogen-containing gas supply source 11 to the anode 2 through the hydrogen-containing gas supply path 6. Oxygen-containing gas is supplied from an oxygen-containing gas supply source 12 to the cathode 3 through the oxygen-containing gas supply path 7. In the fuel cell 5, power generation is performed by an electrochemical reaction between the hydrogen-containing gas and the oxygen-containing gas.

[0042] exist Figure 1 For illustration purposes, ten fuel cells 5 are depicted. However, the number of fuel cells 5 is not particularly limited. The number of fuel cells 5 is two or more. This number may be ten or more, fifty or more, 100 or more, 200 or more, 500 or more, 1,000 or more, or even 3,000 or more. Multiple fuel cells 5 may have the same structure.

[0043] The hydrogen-containing gas may be pure hydrogen or a gas obtained by steam reforming. Examples of the hydrogen-containing gas supply source 11 include hydrogen infrastructure, a reformer, and the like. Typically, the oxygen-containing gas is air. Examples of the oxygen-containing gas supply source 12 include an air blower and the like. Other equipment (not shown) such as a flow control valve is provided in the hydrogen-containing gas supply path 6 and the oxygen-containing gas supply path 7.

[0044] Typically, the fuel cell 5 is a polymer electrolyte fuel cell (PEFC). However, the fuel cell 5 may also be a solid oxide fuel cell (SOFC).

[0045] The control device 8 controls each of the plurality of fuel cells 5. Specifically, the control device 8 controls the start and stop of the fuel cells 5. Thus, the output power of the fuel cell system 100 is adjusted by the control device 8. The control device 8 is, for example, a DSP (Digital Signal Processor) that includes a computing circuit, a memory circuit, and the like. An example of the computing circuit is a CPU. An example of the memory circuit is a memory.

[0046] The control device 8 may also be a single controller. The control device 8 may also include multiple controllers. In a specific example, the control device 8 includes an upper-level controller and multiple lower-level controllers. The upper-level controller controls the multiple lower-level controllers. The multiple lower-level controllers respectively control one or more fuel cells 5 associated with themselves (i.e., the lower-level controller) among the multiple fuel cells 5 included in the fuel cell system 100. The multiple lower-level controllers may also be located physically separated from each other. The upper-level controller may also be located physically separated from the multiple lower-level controllers.

[0047] The power line 13 is connected to the fuel cell 5 and the load 14 . The power generated by each fuel cell 5 is supplied to the load 14 through the power line 13 .

[0048] [1-2. Control Based on Operation Plan in Embodiment]

[0049] The operation and effects of the fuel cell system 100 configured as described above will be described below.

[0050] In the following description, symbols such as J, N, R, M, T1, T2, and D are used. In this embodiment, these symbols are described as follows.

[0051] J is a natural number and is a parameter used in various descriptions.

[0052] N is a natural number greater than or equal to 2. N is the number of fuel cells 5 included in the fuel cell system 100 (hereinafter referred to as the number of installed units). In other words, the fuel cell system 100 includes N fuel cells 5. "The first fuel cell 5 to the Nth fuel cell 5" are descriptions of the N fuel cells 5 with the ordinal number "0" appended thereto. In this embodiment, for all natural numbers J that satisfy 2≤J≤N, the J-1th fuel cell 5 is assigned a higher priority than the Jth fuel cell 5.

[0053] In this embodiment, the control device 8 controls the first fuel cell 5 to the Nth fuel cell 5. The operating mode of the control device 8 includes a specific operating mode. In the specific operating mode, the control device 8 controls the first fuel cell 5 to the Nth fuel cell 5 according to the operating plan 50. The operating plan 50 includes the first stop time to the Nth stop time, and the first start time to the Nth start time. In addition, the operating mode of the control device 8 can be only the specific operating mode, or it can have multiple modes including the specific operating mode. In this embodiment, the specific operating mode can be called a non-stop control mode.

[0054] Here, the expression "controlling the fuel cell 5 according to the operation plan 50" is explained. In reality, there may be a discrepancy between the content of the control performed by the control device 8 according to the operation plan 50 and the actual operation of the fuel cell 5. In this embodiment, even if such a discrepancy occurs, the fuel cell 5 is treated as being controlled according to the operation plan 50. For example, consider the following case: the operation plan 50 is configured so that at a certain time, a certain fuel cell 5 switches from the power generation state to the stopped state and the other fuel cells 5 switch from the stopped state to the power generation state. In this case, in reality, it takes time for the other fuel cells 5 to switch from the stopped state to the power generation state, and the time when the other fuel cells 5 reach the power generation state may be delayed beyond the certain time. This delay may result in a situation where the number of fuel cells 5 in the stopped state is greater than the number indicated in the operation plan 50. Even if such a delay occurs, the fuel cell 5 is treated as being controlled according to the operation plan 50.

[0055] "First Stop Time to Nth Stop Time" refers to a sequence of N stop times, each with a "0th" ordinal number appended. Specifically, "First Stop Time to Nth Stop Time" are the times for switching the first fuel cell 5 to the Nth fuel cell 5 from a power generation state to a stop state, respectively. Below, these may be referred to as the first stop time ta1, the second stop time ta2, the third stop time ta3, the fourth stop time ta4, the fifth stop time ta5, and so on, the Nth stop time taN.

[0056] "First to Nth Startup Time" refers to a series of N startup times, each with a sequential number such as "0" appended to it. Specifically, "First to Nth Startup Time" refers to the times at which the first fuel cell 5 through the Nth fuel cell 5 are switched from a stopped state to a power generation state. Below, these times may be referred to as the first startup time tb1, the second startup time tb2, the third startup time tb3, the fourth startup time tb4, the fifth startup time tb5, and so on, the Nth startup time tbN.

[0057] R is a natural number greater than or equal to 1 and less than N. R is the number of fuel cells 5 that are in a stopped state in the operation plan 50 (hereinafter referred to as the number of standby stations). M is a natural number greater than or equal to N. M is the number of fuel cells 5 that are in a power generation state in the operation plan 50 (hereinafter referred to as the number of power generation stations). In the operation plan 50 of the present embodiment, the number of standby stations R and the number of power generation stations M are maintained constant. More specifically, as can be understood from the description to be described later, the following operation plan 50 is prepared: the number of standby stations R takes the minimum value, and the number of power generation stations M takes the maximum value. Moreover, the first fuel cell 5 to the Nth fuel cell 5 are controlled according to such an operation plan 50. In the specific context to be described later, the expression "maximum number M" is sometimes used.

[0058] T1 is the length of the period during which the fuel cell 5 is stopped (hereinafter referred to as the first prescribed time). In this embodiment, the first prescribed time T1 can be referred to as the stop time. Specifically, the stop time is a cooling stop time for cooling the fuel cell 5. In this embodiment, a first prescribed time T1 is specified for each of the N fuel cells 5. In a typical example, the first prescribed time T1 is the same for the N fuel cells 5.

[0059] T2 is a time related to the stop timing of the fuel cell 5 (hereinafter referred to as a second predetermined time). In this embodiment, the second predetermined time T2 can be referred to as a shift time. The details of the second predetermined time T2 will be described later.

[0060] D is the initial value of the time during which the fuel cell 5 can generate electricity. Specifying the initial value D can be beneficial. For example, if the fuel cell 5 is operated for an excessively long time without setting an appropriate stop time, components other than hydrogen may accumulate in the cathode, causing the cathode to be contaminated. If the cathode is contaminated, the output voltage of the fuel cell 5 decreases. In this way, "deterioration" occurs, in which the output voltage of the fuel cell 5 decreases. By appropriately specifying the initial value D, degradation can be suppressed. In this embodiment, an initial value D is specified for each of the N fuel cells 5. In a typical example, the initial value D of the N fuel cells 5 is the same.

[0061] For all natural numbers J that satisfy 1≤J≤N, the power generation time of the Jth fuel cell 5 is counted. In the following, the time obtained by this count may be referred to as the "count time TC". The count time TC is reset when the fuel cell 5 stops continuously for the third prescribed time T3. In other words, the count time TC is the time obtained by counting the time when the fuel cell 5 does not stop continuously for more than the third prescribed time T3 and generates power continuously or intermittently. In addition, the "count time TC" related to intermittent power generation is the sum of the values ​​obtained by counting multiple power generation times separated from each other in time. In this embodiment, the third prescribed time T3 is equal to the first prescribed time T1.

[0062] The "remaining time of power generation" is the difference obtained by subtracting the count time TC of a fuel cell 5 from the initial value D of that fuel cell 5. Furthermore, the "moment when the power generation time expires" is the moment when the count time TC of the fuel cell 5 reaches the initial value D. In other words, the "moment when the power generation time expires" is the moment when the remaining time of power generation becomes zero. The "specific remaining time" is the remaining time of power generation at the start of a specific operating mode. In this embodiment, the "remaining time of power generation" is determined by the control device 8. Similarly, the "specific remaining time" is determined by the control device 8.

[0063] [1-2-1. Control based on operation plan in the first example]

[0064] Next, refer to the first example Figures 2 to 4 The control based on the operation plan 50 in the embodiment will be described. In the first example, the number of installed units N, the first predetermined time T1, and the initial value D are as follows.

[0065] N = 61 units

[0066] T1 = 2 hours

[0067] D = 120 hours

[0068] The number of standby stations R, the number of transmitting stations M, and the second predetermined time T2 take values ​​that depend on the number of installed stations N, the first predetermined time T1, and the initial value D. As will be understood from the following description, in the first example, the number of standby stations R, the number of transmitting stations M, and the second predetermined time T2 take the following values.

[0069] R = 1 unit

[0070] M = 60 units

[0071] T2 = 2 hours

[0072] Figure 2 : is an explanatory diagram showing the number of transmission stations M involved in the first example. Figure 2 In the figure, the horizontal axis is time. The vertical axis is the number of transmitting stations M. Figure 2 As shown, in the operation plan 50 of the first example, the number of transmission stations M is maintained constant.

[0073] Figure 3 : is an explanatory diagram of the operation plan 50 involved in the first example. Figure 3 In , the horizontal axis is time. Figure 3 In the figure, unit 1, unit 2, unit 3, unit 4, unit 5 ... unit N refer to the first fuel cell 5, the second fuel cell 5, the third fuel cell 5, the fourth fuel cell 5, the fifth fuel cell 5 ... the Nth fuel cell 5 respectively.

[0074] In this embodiment, the first stop time ta1 corresponds to the specific remaining time of the first fuel cell 5 and is the time for switching the first fuel cell 5 from the power generation state to the stop state. For all natural numbers J satisfying 2≤J≤N, the Jth stop time taJ is the time for switching the Jth fuel cell 5 from the power generation state to the stop state, whichever is earlier (i.e., earlier) than the second predetermined time T2 from the J-1th stop time ta(J-1) or the time corresponding to the specific remaining time of the Jth fuel cell 5. For all natural numbers J satisfying 1≤J≤N, the Jth start time tbJ is the time for switching the Jth fuel cell 5 from the stop state to the power generation state, which is the time after the first predetermined time T1 has passed from the Jth stop time taJ. The operation plan 50 does not include periods in which more than R fuel cells 5 from the first to Nth fuel cells 5 are in the stop state. With this configuration, the stopped fuel cells 5 from the first to Nth fuel cells 5 can be sequentially switched while maintaining the number of power generation stations M at NR or more. Therefore, by suppressing the “deterioration” of the output voltage drop of each fuel cell 5 , the reliability of the fuel cell 5 can be ensured, and the generated power of NR or more units can be continuously obtained.

[0075] In addition, Figure 3 and Figure 4 , the case where "the earlier time between the second predetermined time T2 from the J-1 stop time ta(J-1) and the time corresponding to the specific remaining time of the J-th fuel cell 5" is "the earlier time between the second predetermined time T2 from the J-1 stop time ta(J-1)". Figure 5 Same here.

[0076] In this embodiment, for all natural numbers J that satisfy 2≤J≤N, the specific remaining time of the J-1th fuel cell 5 is greater than the specific remaining time of the J-th fuel cell 5. This configuration allows for effective utilization of the length of the available power generation time. This reduces the number of stops and starts of the fuel cells 5 in the fuel cell system 100 as a whole. This also reduces the "deterioration" of the output voltage drop of each fuel cell 5. It is possible that for all natural numbers J that satisfy 2≤J≤N, the specific remaining time of the J-1th fuel cell 5 is longer than the specific remaining time of the J-th fuel cell 5. On the other hand, it is possible that for at least one natural number J that satisfies 2≤J≤N, the specific remaining time of the J-1th fuel cell 5 is the same as the specific remaining time of the J-th fuel cell 5. In this case, for example, the cumulative power generation time of the J-1th fuel cell 5 at the start of a specific operating mode is shorter than the cumulative power generation time of the J-th fuel cell 5 at the start of the specific operating mode.

[0077] In this embodiment, in the operation plan 50, the periods during which the first through Nth fuel cells 5 are in the stopped state are at least partially staggered so that M is maximized, and the number of fuel cells 5 in the first through Nth fuel cells 5 that are in the power generation state is maintained at M. R = NM. This configuration of the reserve number R allows the fuel cell system 100 as a whole to continuously generate high levels of power.

[0078] R can be a minimum natural number greater than or equal to N×T1 / (D+T1) or a maximum natural number less than or equal to N×T1 / (D+T1). The number R of spare units in this configuration allows the fuel cell system 100 to continuously generate high power.

[0079] The output power of the fuel cell system 100 may be smaller than the power requested by the load 14. In this case, for example, power is supplied from a power storage device (not shown) in the fuel cell system 100 to the load 14. This can supplement the insufficient power.

[0080] In this embodiment, in the operation plan 50 , the number of fuel cells in the stopped state among the first fuel cell 5 to the Nth fuel cell 5 is maintained at R. With this configuration, the fuel cell system 100 as a whole can continuously generate constant and high power.

[0081] In this embodiment, T2 is the value given by T1 / R. This configuration of T2 enables continuous high power generation. The "value given by T1 / R" may also be T1 / R itself. If T1 / R is not divisible, the "value given by T1 / R" may be the value obtained by rounding T1 / R to a specified number of digits. If control device 8 has a control cycle, the "value given by T1 / R" may be the value closest to T1 / R among integer multiples of the control cycle.

[0082] In this embodiment, for all natural numbers J satisfying 1 ≤ J ≤ N, the time corresponding to the specific remaining time of the Jth fuel cell 5 is the time when the power generation time of the Jth fuel cell 5 expires. This configuration allows for effective utilization of the length of the power generation time associated with at least one fuel cell 5.

[0083] In the operation plan 50 of this embodiment, for all natural numbers J satisfying 1 ≤ J ≤ N, the Jth fuel cell 5 repeats continuous power generation for a continuous period of time equal to the initial value D and a continuous stop for a continuous first predetermined period of time T1 after the Jth start time tbJ. In the operation plan 50 of this embodiment, similarly to the period from the Nth stop time taN to the first start time tb1, the number of stopped fuel cells among the first through Nth fuel cells 5 is maintained at R or less after the Jth start time tbJ. Specifically, similarly to the period from the Nth stop time taN to the first start time tb1, the number of stopped fuel cells among the first through Nth fuel cells 5 is maintained at R after the Jth start time tbJ.

[0084] Figure 4 : is an explanatory diagram of the frequency of switching any one of the first fuel cell 5 to the Nth fuel cell 5 from the power generation state to the stop state in the first example. Figure 4 In the example, the time interval for the switching is equal to the second prescribed time T2 and also equal to the first prescribed time T1.

[0085] [1-2-2. Operation plan in the second example]

[0086] Next, the second example will be described. In the second example, descriptions common to the first example may be omitted. In the second example, the number of units N, the first predetermined time T1, and the initial value D are as follows.

[0087] N = 244 units

[0088] T1 = 2 hours

[0089] D = 120 hours

[0090] As described above, the number of standby stations R, the number of transmitting stations M, and the second predetermined time T2 take values ​​depending on the number of installed stations N, the first predetermined time T1, and the initial value D. In the second example, the number of standby stations R, the number of transmitting stations M, and the second predetermined time T2 take the following values.

[0091] R = 4 units

[0092] M = 240 units

[0093] T2 = 30 minutes

[0094] Figure 5 : is an explanatory diagram of the frequency of switching any one of the first fuel cell 5 to the Nth fuel cell 5 from the power generation state to the stop state in the second example. Figure 5 In the example, the time interval for the switching is equal to the second prescribed time T2 and also equal to 1 / 4 of the first prescribed time T1.

[0095] In this embodiment, the following case is considered: the first predetermined time T1 = 2 hours, the initial value D = 120 hours, and the number of reserve units R is set to the smallest natural number greater than N × T1 / (D + T1). In this case, Table 1 below shows the number of reserve units R and the second predetermined time T2 for setting the maximum number M to 1 to 60 units, 61 to 120 units, 121 to 180 units, 181 to 240 units, and 241 to 250 units, respectively.

[0096] [Table 1]

[0097] Maximum number of units M Number of spare units R Second prescribed time T2 1 to 60 units 1 unit 120 minutes 61 to 120 units 2 units 60 minutes 121 to 180 units 3 units 40 minutes 181 to 240 units 4 units 30 minutes 241 to 250 units 5 units 24 minutes

[0098] [1-2-3. Creation of Operation Plan in Implementation Method]

[0099] The operation plan 50 is created by the control device 8 . Figure 6 4 is a flowchart for explaining the creation of the operation plan 50 in the embodiment. In the present embodiment, the count time TC is counted by the control device 8 .

[0100] In step S1, the control device 8 determines the number of reserve units, R. In this embodiment, the control device 8 calculates N × T1 / (D + T1). If the calculated value contains a decimal point, the calculated value is rounded up to a natural number. This determines R. The thus determined R is the smallest natural number greater than or equal to N × T1 / (D + T1).

[0101] In step S1 of the modified example, control device 8 calculates N×T1 / (D+T1). If the calculated value contains a decimal point, the value is rounded to the first decimal point to correct the calculated value to a natural number. This determines R. The thus determined R is the smallest natural number greater than or equal to N×T1 / (D+T1) or the largest natural number less than or equal to N×T1 / (D+T1).

[0102] In step S2, the control device 8 determines the second predetermined time T2. In the present embodiment, the control device 8 determines T2 to be a value given by T1 / R.

[0103] In step S3 , the control device 8 assigns priorities to the N fuel cells 5 according to at least one rule. Thus, the control device 8 divides the N fuel cells 5 into the first fuel cell 5 to the Nth fuel cell 5 .

[0104] The at least one rule includes a first rule. The first rule is a rule that the greater the difference obtained by subtracting the count time TC of the fuel cell 5 from the initial value D of the fuel cell 5, the higher the priority of the fuel cell 5. Specifically, the first rule is a rule that the greater the difference obtained by subtracting the count time TC of the fuel cell 5 when the operation plan 50 was created from the initial value D of the fuel cell 5, the higher the priority of the fuel cell 5.

[0105] The at least one rule includes a second rule. The second rule is a rule that, when the difference obtained by subtracting the counted time TC of the fuel cell 5 from the initial value D of the fuel cell 5 is the same, the shorter the cumulative power generation time of the fuel cell 5, the higher the priority of the fuel cell 5. Specifically, the second rule is a rule that, when the difference obtained by subtracting the counted time TC of the fuel cell 5 when the operation plan 50 was created from the initial value D of the fuel cell 5 is the same, the shorter the cumulative power generation time of the fuel cell 5 when the operation plan 50 was created, the higher the priority of the fuel cell 5.

[0106] In the specific example of step S3, the N fuel cells 5 are sorted in descending order according to the difference obtained by subtracting the count time TC of the fuel cell 5 from the initial value D of the fuel cell 5. For the fuel cells 5 with the same difference, they are sorted in order from short to long according to the cumulative power generation time of the fuel cell 5. Then, based on the sorting result, priorities are assigned to the N fuel cells 5. Thus, the control device 8 divides the N fuel cells 5 into the first fuel cell 5 to the Nth fuel cell 5. In the above context, the "count time TC of the fuel cell 5" is specifically the "count time TC of the fuel cell 5 when the operation plan 50 is made." The "cumulative power generation time of the fuel cell 5" is specifically the "cumulative power generation time of the fuel cell 5 when the operation plan 50 is made."

[0107] In step S4, for all natural numbers J that satisfy 1≤J≤N, the control device 8 calculates the Jth calculation time based on the initial value D of the Jth fuel cell 5 and the count time TC of the Jth fuel cell 5. Specifically, for all natural numbers J that satisfy 1≤J≤N, the control device 8 calculates the Jth calculation time based on the initial value D of the Jth fuel cell 5 and the count time TC of the Jth fuel cell 5 when the operation plan 50 was created. More specifically, for all natural numbers J that satisfy 1≤J≤N, the control device 8 calculates the Jth calculation time by subtracting the count time TC of the Jth fuel cell 5 when the operation plan 50 was created from the initial value D of the Jth fuel cell 5, calculating the difference, and adding the difference to the creation time of the operation plan 50 to calculate the Jth calculation time.

[0108] In step S5 , the control device 8 determines the first calculation time as the first stop time ta1 .

[0109] In step S6 , for all natural numbers J satisfying 2≦J≦N, the control device 8 calculates the J-th tentative time by subtracting the second predetermined time T2 from the J-1-th stop time ta(J-1).

[0110] In step S7 , for all natural numbers J satisfying 2≦J≦N, the control device 8 determines the earlier time between the J-th tentative time and the J-th calculated time as the J-th stop time taJ.

[0111] In step S8 , for all natural numbers J satisfying 1≦J≦N, the control device 8 calculates the J-th start time tbJ by adding the first predetermined time T1 to the J-th stop time taJ.

[0112] Through steps S1 to S8 , the control device 8 creates the operation plan 50 so that the operation plan 50 does not include a period in which more than R fuel cells 5 from the first to Nth fuel cells 5 are in a stopped state.

[0113] Furthermore, the above description regarding steps S1 to S8 is not intended to necessarily execute steps S1 to S8 in a specific operation mode. Furthermore, the above description is not intended to limit the order of creating the operation plan 50.

[0114] In a specific example, steps S1 and S2 are executed before the start of the specific operating mode. Steps S3 to S8 are executed during the specific operating mode. Regarding steps S5 to S8, the control device 8 advances the processing in the following order: (1), (2), (3), (4), (5), ... (N). That is, for all natural numbers J that satisfy 1 ≤ J ≤ N, the process of "determining the Jth stop time taJ and then determining the Jth start time tbJ" is executed in the order of increasing J.

[0115] (1) The first stop time ta1 is determined, and then the first start time tb1 is determined.

[0116] (2) The second stop time ta2 is determined, and then the second start time tb2 is determined.

[0117] (3) The third stop time ta3 is determined, and then the third start time tb3 is determined.

[0118] (4) The fourth stop time ta4 is determined, and then the fourth start time tb4 is determined.

[0119] (5) The fifth stop time ta5 is determined, and then the fifth start time tb5 is determined.

[0120] …

[0121] (N) The Nth stop time taN is determined, and then the Nth start time tbN is determined.

[0122] [1-3. Effects, etc.]

[0123] According to this embodiment, the reliability of the fuel cell system 100 can be ensured while continuously extracting power from the fuel cell system 100. Specifically, it is possible to implement control that sequentially switches the stopped fuel cells 5 while maintaining the generated power of the entire fuel cell system 100 constant. This control can be used for various applications.

[0124] (Note)

[0125] The present disclosure discloses the following technology.

[0126] (Technique 1) A fuel cell system comprising:

[0127] First to Nth fuel cells, the first to Nth fuel cells being specified with an initial value of a power-generating time and a first specified time, wherein N is a natural number greater than or equal to 2; and

[0128] a control device for controlling the first fuel cell to the Nth fuel cell,

[0129] The operating mode of the control device includes a specific operating mode. In the specific operating mode, the control device controls the first fuel cell to the Nth fuel cell according to the operating plan.

[0130] The operation plan includes the first stop time to the Nth stop time, and the first start time to the Nth start time,

[0131] When the remaining time of the power generation possible time at the start of the specific operation mode is defined as a specific remaining time,

[0132] The first stop time is a time corresponding to the specific remaining time of the first fuel cell and is a time for switching the first fuel cell from a power generation state to a stop state.

[0133] For all natural numbers J satisfying 2≤J≤N, the Jth stop time is a time for switching the Jth fuel cell from a power generation state to a stop state, and is the earlier of a time before the second predetermined time from the J-1th stop time and a time corresponding to the specific remaining time of the Jth fuel cell.

[0134] For all natural numbers J that satisfy 1≤J≤N, the Jth start-up time is the time for switching the Jth fuel cell from the stop state to the power generation state, and is the time when the first predetermined time has elapsed from the Jth stop time.

[0135] The operation plan does not include a period in which more than R fuel cells from the first to Nth fuel cells are in a stopped state, where R is a natural number greater than or equal to 1 and less than N.

[0136] Technology 1 is suitable for ensuring the reliability of the fuel cell system and for continuously extracting electric power from the fuel cell system.

[0137] (Technique 2) The fuel cell system described in Technique 1, wherein:

[0138] For all natural numbers J satisfying 2≤J≤N, the specific remaining time of the J-1th fuel cell is equal to or longer than the specific remaining time of the Jth fuel cell.

[0139] According to the technique 2, it is easy to control the degradation of each fuel cell.

[0140] (Technique 3) The fuel cell system according to Technique 1 or 2, wherein:

[0141] In the operation plan, periods during which the first to Nth fuel cells are in a stopped state are at least partially staggered so that M becomes maximum, and the number of fuel cells in a power generation state among the first to Nth fuel cells is maintained at M, where M is a natural number greater than 1 and less than N.

[0142] R=NM.

[0143] (Technique 4) The fuel cell system described in Technique 3, wherein:

[0144] In the operation plan, the number of fuel cells in the stopped state among the first fuel cell to the Nth fuel cell is maintained at R.

[0145] (Technique 5) The fuel cell system according to Technique 3 or 4, wherein:

[0146] When the first prescribed time is recorded as T1 and the second prescribed time is recorded as T2,

[0147] T2 is the value given by T1 / R.

[0148] (Technique 6) The fuel cell system according to any one of Techniques 1 to 5, wherein:

[0149] When the initial value of the first fuel cell to the Nth fuel cell is recorded as D and the first predetermined time is recorded as T1,

[0150] R is the smallest natural number greater than or equal to N×T1 / (D+T1) or the largest natural number less than or equal to N×T1 / (D+T1).

[0151] According to R related to Technique 3 and Technique 6, it is easy to continuously generate large electric power as a whole fuel cell system.

[0152] (Technique 7) The fuel cell system described in Technique 6, wherein:

[0153] In the operation plan, the number of fuel cells in the stopped state among the first fuel cell to the Nth fuel cell is maintained at R.

[0154] According to R related to Technique 4 and Technique 7, it is easy to continuously generate constant and large electric power as a whole fuel cell system.

[0155] (Technique 8) The fuel cell system according to Technique 6 or 7, wherein:

[0156] When the second prescribed time is recorded as T2,

[0157] T2 is the value given by T1 / R.

[0158] T2 involved in Techniques 5 and 8 enables continuous generation of high power.

[0159] (Technique 9) The fuel cell system according to any one of Techniques 1 to 8, wherein:

[0160] For all natural numbers J satisfying 1≤J≤N, the time corresponding to the specific remaining time of the Jth fuel cell is the time when the power-generating time of the Jth fuel cell expires.

[0161] According to the ninth technique, the length of time during which power generation is possible for at least one fuel cell can be effectively utilized.

[0162] (Technique 10) The fuel cell system according to any one of Techniques 1 to 9, wherein:

[0163] The control device creates the operation plan so that the operation plan does not include a period in which more than R fuel cells from the first fuel cell to the Nth fuel cell are in a stopped state by the following processing:

[0164] For all natural numbers J that satisfy 1≤J≤N, the power generation time of the Jth fuel cell is counted.

[0165] For all natural numbers J that satisfy 1≤J≤N, the Jth calculation time is calculated based on the initial value of the Jth fuel cell and the counted power generation time of the Jth fuel cell.

[0166] determining the first calculation time as the first stop time,

[0167] For all natural numbers J that satisfy 2≤J≤N, the J-th provisional time is calculated by subtracting the second prescribed time from the J-1-th stop time.

[0168] For all natural numbers J that satisfy 2≤J≤N, the earlier of the Jth provisional time and the Jth calculation time is determined as the Jth stop time.

[0169] For all natural numbers J satisfying 1≤J≤N, the Jth start time is calculated by adding the first prescribed time to the Jth stop time.

[0170] The technique 10 is suitable for creating an operation plan that ensures the reliability of the fuel cell system and enables the continued extraction of power from the fuel cell system.

[0171] (Technique 11) The fuel cell system according to any one of Techniques 1 to 10, wherein:

[0172] For all natural numbers J that satisfy 2≤J≤N, the J-1th fuel cell is assigned a higher priority than the Jth fuel cell.

[0173] The control device divides the N fuel cells into the first fuel cell to the Nth fuel cell by assigning priorities to the N fuel cells according to at least one rule,

[0174] The at least one rule comprises a first rule,

[0175] The first rule is a rule that the greater the difference obtained by subtracting the counted power generation time of the fuel cell from the initial value of the fuel cell, the higher the priority of the fuel cell.

[0176] Technique 11 is suitable for creating an operation plan suitable for suppressing the degradation of each fuel cell.

[0177] (Technique 12) A method for operating a fuel cell system, the fuel cell system comprising a first fuel cell to an Nth fuel cell for which an initial value of a power generation time and a first predetermined time are specified, wherein N is a natural number greater than or equal to 2, wherein:

[0178] The operating method includes controlling the first fuel cell to the Nth fuel cell according to an operating plan in a specific operating mode,

[0179] The operation plan includes the first stop time to the Nth stop time, and the first start time to the Nth start time,

[0180] When the remaining time of the power generation possible time at the start of the specific operation mode is defined as a specific remaining time,

[0181] The first stop time is a time corresponding to the specific remaining time of the first fuel cell and is a time for switching the first fuel cell from a power generation state to a stop state.

[0182] For all natural numbers J satisfying 2≤J≤N, the Jth stop time is a time for switching the Jth fuel cell from a power generation state to a stop state, and is the earlier of a time before the second predetermined time from the J-1th stop time and a time corresponding to the specific remaining time of the Jth fuel cell.

[0183] For all natural numbers J that satisfy 1≤J≤N, the Jth start-up time is the time for switching the Jth fuel cell from the stop state to the power generation state, and is the time when the first predetermined time has elapsed from the Jth stop time.

[0184] The operation plan does not include a period in which more than R fuel cells from the first to Nth fuel cells are in a stopped state, where R is a natural number greater than or equal to 1 and less than N.

[0185] (Technique 13) A computer program including instructions for causing a computer to execute the operation method described in Technique 12 when the computer program is executed by the computer.

[0186] (Technique 14) A computer-readable non-transitory recording medium having the computer program described in Technique 13 recorded thereon.

[0187] Techniques 12 to 14 are suitable for ensuring the reliability of the fuel cell system and for continuously extracting power from the fuel cell system.

[0188] A computer can include a processor and a memory. Examples of the processor include a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), and an FPGA (Field Programmable Gate Array).

[0189] Examples of memory include semiconductor recording media, magnetic recording media, magneto-optical recording media, and optical recording media. Examples of semiconductor recording media include SD (Secure Digital) cards, USB (Universal Serial Bus) memories, and SSDs (Solid State Drives). Examples of magnetic recording media include HDDs (Hard Disk Drives) and floppy disks. Examples of magneto-optical recording media include MOs (Magneto Optical Disks). Examples of optical recording media include CDs (Compact Discs) and DVDs (Digital Versatile Discs).

[0190] Unless there is any particular contradiction, the structure of techniques 1 to 11 can be applied to techniques 12 to 14 , and the structure of techniques 12 to 14 can be applied to techniques 1 to 11 .

[0191] Industrial applicability

[0192] The technology disclosed herein is useful for a fuel cell system including a plurality of fuel cells.

[0193] Description of Reference Numerals

[0194] 1: Electrolyte membrane; 2: Anode; 3: Cathode; 5: Fuel cell; 6: Hydrogen-containing gas supply path; 7: Oxygen-containing gas supply path; 8: Control device; 11: Hydrogen-containing gas supply source; 12: Oxygen-containing gas supply source; 13: Power line; 14: Load; 50: Operation plan; 100: Fuel cell system.

Claims

1. A fuel cell system comprising: The first fuel cell to the Nth fuel cell are provided with an initial value of a power generation time and a first prescribed time, wherein: N is a natural number greater than 2; as well as a control device for controlling the first fuel cell to the Nth fuel cell, The operating mode of the control device includes a specific operating mode. In the specific operating mode, the control device controls the first fuel cell to the Nth fuel cell according to the operating plan. The operation plan includes the first stop time to the Nth stop time, and the first start time to the Nth start time, When the remaining time of the power generation possible time at the start of the specific operation mode is defined as a specific remaining time, The first stop time is a time corresponding to the specific remaining time of the first fuel cell and is a time for switching the first fuel cell from a power generation state to a stop state. For all natural numbers J satisfying 2≤J≤N, the Jth stop time is a time for switching the Jth fuel cell from a power generation state to a stop state, and is the earlier of a time before the second predetermined time from the J-1th stop time and a time corresponding to the specific remaining time of the Jth fuel cell. For all natural numbers J that satisfy 1≤J≤N, the Jth start-up time is the time for switching the Jth fuel cell from the stop state to the power generation state, and is the time when the first predetermined time has elapsed from the Jth stop time. The operation plan does not include a period in which more than R fuel cells from the first to Nth fuel cells are in a stopped state, where R is a natural number greater than or equal to 1 and less than N.

2. The fuel cell system according to claim 1, wherein: For all natural numbers J satisfying 2≤J≤N, the specific remaining time of the J-1th fuel cell is equal to or longer than the specific remaining time of the Jth fuel cell.

3. The fuel cell system according to claim 1 or 2, wherein: In the operation plan, periods during which the first to Nth fuel cells are in a stopped state are at least partially staggered so that M becomes maximum, and the number of fuel cells in a power generation state among the first to Nth fuel cells is maintained at M, where M is a natural number greater than 1 and less than N. R=NM.

4. The fuel cell system according to claim 3, wherein: In the operation plan, the number of fuel cells in the stopped state among the first fuel cell to the Nth fuel cell is maintained at R.

5. The fuel cell system according to claim 3, wherein: When the first prescribed time is recorded as T1 and the second prescribed time is recorded as T2, T2 is the value given by T1 / R.

6. The fuel cell system according to claim 1 or 2, wherein: When the initial value of the first fuel cell to the Nth fuel cell is recorded as D and the first predetermined time is recorded as T1, R is the smallest natural number greater than or equal to N×T1 / (D+T1) or the largest natural number less than or equal to N×T1 / (D+T1).

7. The fuel cell system according to claim 6, wherein: In the operation plan, the number of fuel cells in the stopped state among the first fuel cell to the Nth fuel cell is maintained at R.

8. The fuel cell system according to claim 6, wherein: When the second prescribed time is recorded as T2, T2 is the value given by T1 / R.

9. The fuel cell system according to claim 1 or 2, wherein: For all natural numbers J satisfying 1≤J≤N, the time corresponding to the specific remaining time of the Jth fuel cell is the time when the power-generating time of the Jth fuel cell expires.

10. The fuel cell system according to claim 1 or 2, wherein: The control device creates the operation plan so that the operation plan does not include a period in which more than R fuel cells from the first fuel cell to the Nth fuel cell are in a stopped state by the following processing: For all natural numbers J that satisfy 1≤J≤N, the power generation time of the Jth fuel cell is counted. For all natural numbers J that satisfy 1≤J≤N, the Jth calculation time is calculated based on the initial value of the Jth fuel cell and the counted power generation time of the Jth fuel cell. determining the first calculation time as the first stop time, For all natural numbers J that satisfy 2≤J≤N, the J-th provisional time is calculated by subtracting the second prescribed time from the J-1-th stop time. For all natural numbers J that satisfy 2≤J≤N, the earlier of the Jth provisional time and the Jth calculation time is determined as the Jth stop time. For all natural numbers J satisfying 1≤J≤N, the Jth start time is calculated by adding the first prescribed time to the Jth stop time.

11. The fuel cell system according to claim 1 or 2, wherein: For all natural numbers J that satisfy 2≤J≤N, the J-1th fuel cell is assigned a higher priority than the Jth fuel cell. The control device divides the N fuel cells into the first fuel cell to the Nth fuel cell by assigning priorities to the N fuel cells according to at least one rule, The at least one rule comprises a first rule, The first rule is a rule that the greater the difference obtained by subtracting the counted power generation time of the fuel cell from the initial value of the fuel cell, the higher the priority of the fuel cell.

12. A method for operating a fuel cell system, the fuel cell system comprising a first fuel cell to an Nth fuel cell for which an initial value of a power generation time and a first predetermined time are specified, wherein: N is a natural number greater than 2, where The operating method includes controlling the first fuel cell to the Nth fuel cell according to an operating plan in a specific operating mode, The operation plan includes the first stop time to the Nth stop time, and the first start time to the Nth start time, When the remaining time of the power generation possible time at the start of the specific operation mode is defined as a specific remaining time, The first stop time is a time corresponding to the specific remaining time of the first fuel cell and is a time for switching the first fuel cell from a power generation state to a stop state. For all natural numbers J satisfying 2≤J≤N, the Jth stop time is a time for switching the Jth fuel cell from a power generation state to a stop state, and is the earlier of a time before the second predetermined time from the J-1th stop time and a time corresponding to the specific remaining time of the Jth fuel cell. For all natural numbers J that satisfy 1≤J≤N, the Jth start-up time is the time for switching the Jth fuel cell from the stop state to the power generation state, and is the time when the first predetermined time has elapsed from the Jth stop time. The operation plan does not include a period in which more than R fuel cells from the first to Nth fuel cells are in a stopped state, where R is a natural number greater than or equal to 1 and less than N. 13 . A computer program comprising instructions for causing a computer to execute the operation method according to claim 12 when the computer program is executed by the computer. 14 . A computer-readable non-transitory recording medium having the computer program according to claim 13 recorded thereon.

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