Prediction method, prediction device, and electric power generation system

Abstract

A prediction method according to the present disclosure comprises: a step for predicting a timing at which the electric power that can be outputted by a fuel cell device, which includes a plurality of fuel cell units, will become less than a prescribed threshold value that is equal to or higher than the rated output of the fuel cell device; and a step for notifying a display device regarding information that indicates the timing.

Description

Prediction method, prediction device, and power generation system

[0001] The present disclosure relates to a prediction method, a prediction device, and a power generation system.

[0002] Various proposals have been made regarding fuel cell degradation prediction. For example, Patent Document 1 discloses a fuel cell system including a reformer for reforming fuel gas, a cell stack including a plurality of fuel cell units for generating electricity by oxidizing and reducing the reformed fuel gas reformed in the reformer and an oxidant, a fuel gas pump for supplying fuel gas to the reformer, an oxidant blower for supplying the oxidant to the cell stack, a water pump for supplying reforming water to the reformer, and a controller for controlling the fuel gas pump, the oxidant blower, and the water pump, wherein the controller includes stack degradation diagnosis means for diagnosing degradation of the cell stack, the stack degradation diagnosis means including stack degradation gradient value calculation means for calculating a degradation progression state of the cell stack at intervals of a degradation diagnosis period, stack degradation prediction value calculation means for calculating a stack degradation prediction value at a reference lifetime based on the stack degradation gradient value calculated by the stack degradation gradient value calculation means, and stack degradation determination means for determining whether degradation is progressing based on the stack degradation prediction value calculated by the stack degradation prediction value calculation means.

[0003] Japanese Patent Application Laid-Open No. 2018-147847

[0004] As an example, an object of the present disclosure is to provide a prediction method, a prediction device, and a power generation system that, unlike conventional examples, are capable of appropriately predicting the deterioration of a fuel cell device including multiple fuel cell units.

[0005] In order to solve the above problem, a prediction method according to one aspect of the present disclosure includes the steps of predicting when the output power of a fuel cell device including a plurality of fuel cell units will fall below a predetermined threshold value equal to or greater than the rated output of the fuel cell device, and notifying a display device of information indicating the time.

[0006] In addition, a prediction device according to one aspect of the present disclosure includes a controller that predicts when the output power of a fuel cell device including a plurality of fuel cell units will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device, and a communicator that, under the control of the controller, notifies a display device of information indicating the time.

[0007] A power generation system according to one aspect of the present disclosure includes the prediction device described above and a fuel cell device including a plurality of fuel cell units.

[0008] Unlike conventional examples, the prediction method, prediction device, and power generation system according to one aspect of the present disclosure have the advantage of being able to appropriately predict the deterioration of a fuel cell device including a plurality of fuel cell units.

[0009] FIG. 1 is a diagram illustrating an example of a power generation system according to an embodiment. FIG. 2 is a diagram illustrating an example of a prediction device of FIG. 1. FIG. 3 is a flowchart illustrating an example of the operation (prediction method) of the prediction device in the power generation system according to an embodiment. FIG. 4 is a flowchart illustrating an example of the operation (prediction method) of the prediction device in the power generation system according to a first example of the embodiment. FIG. 5 is a diagram illustrating an example of an approximate line showing the correlation between the average cumulative power generation time of each fuel cell unit and the outputtable power of the fuel cell device calculated from the average maximum output of each fuel cell unit corresponding to the average cumulative power generation time. FIG. 6 is a diagram illustrating an example of voltage stabilization timing when the voltage stabilizes after a predetermined time has elapsed since the start of power generation of the fuel cell unit. FIG. 7 is a flowchart illustrating an example of the operation (prediction method) of the prediction device in the power generation system according to a second example of the embodiment. FIG. 8 is a diagram illustrating an example of a method for deriving the proportion of the period during which the fuel cell unit is generating power in a predetermined period. FIG. 9 is a flowchart illustrating an example of the operation (prediction method) of the prediction device in the power generation system according to a fifth example of the embodiment.

[0010] Patent document 1 considers the prediction of deterioration of the cell stack of a single fuel cell, but does not consider the prediction of deterioration in cases where the output power of a fuel cell device including multiple fuel cells is greater than the rated output guaranteed for the device as a fuel cell device.

[0011] Therefore, the prediction method of the first aspect of the present disclosure includes a step of predicting the time when the output power of a fuel cell device including a plurality of fuel cell units will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device, and a step of notifying a display device of information indicating the time.

[0012] According to the above, the prediction method of this aspect, unlike the conventional example, can appropriately predict the deterioration of a fuel cell device including a plurality of fuel cell units.

[0013] Specifically, the prediction method of this aspect compares the available power output of a fuel cell device including multiple fuel cell units with the rated power guaranteed for the device. This makes it possible to notify information indicating when the available power output of the fuel cell device will fall below a predetermined threshold equal to or greater than the rated power output, to an information terminal of a consumer receiving power supply service generated by the fuel cell device, a display device of a maintenance company, etc. This allows the consumer or maintenance worker (hereinafter referred to as "consumer") to take timely measures, such as replacing or adding fuel cell units, to prevent the available power output of the fuel cell device from falling below the rated power, compared to when such information is not notified.

[0014] The prediction method of the second aspect of the present disclosure may, in the prediction method of the first aspect, predict the time when the output power of the fuel cell device will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device, based on a prediction of a decrease in the output power of the fuel cell device due to deterioration of multiple fuel cell units.

[0015] It is generally known that as the cumulative power generation time of each fuel cell unit increases, the voltage of the fuel cell unit decreases due to deterioration of the fuel cell unit.

[0016] Therefore, for example, the maximum output power that will decrease over the cumulative power generation time of the fuel cell device can be predicted from the transition of the maximum output power of the fuel cell device over the cumulative power generation time of the fuel cell device in the past.The cumulative power generation time at which this predicted maximum output reaches the threshold value can be appropriately derived as the time when the maximum output power of the fuel cell device will fall below the threshold value.

[0017] The prediction method of the third aspect of the present disclosure may predict, in the prediction method of the first or second aspect, the time when the output power of the fuel cell device will fall below a predetermined threshold that is equal to or greater than the rated output of the fuel cell device, based on the cumulative power generation time of the fuel cell device at which the output power of the fuel cell device is predicted to fall below a predetermined threshold and the proportion of the period during which the fuel cell unit is generating power within a predetermined period.

[0018] Here, "the proportion of the period during which the fuel cell unit is generating electricity in a predetermined period" corresponds to the operating rate of the fuel cell unit in the predetermined period.

[0019] As a result, the prediction method of this aspect can predict more accurately than conventional methods when the outputtable power of the fuel cell device will fall below a predetermined threshold that is equal to or greater than the rated output of the fuel cell device.

[0020] Specifically, when each fuel cell unit is used approximately evenly over a given period of time, the utilization rate of each fuel cell unit is approximately equal to the above-mentioned operating rate. Furthermore, the higher the utilization rate of a fuel cell unit, the faster the deterioration of that fuel cell unit progresses.

[0021] As described above, the prediction method of this embodiment takes the above-mentioned operating rate into account when predicting the time when the output power of the fuel cell device will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device, and can therefore more accurately predict the time when the output power of the fuel cell device will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device than when such operating rate is not taken into account.

[0022] A prediction method of a fourth aspect of the present disclosure is a prediction method of any one of the first to third aspects, wherein the fuel cell device may include a number of fuel cell units greater than the number of fuel cell units required for the rated output of the fuel cell device calculated from the rated output of the fuel cell units.

[0023] As described above, the prediction method of this embodiment appropriately ensures that the output power of the fuel cell device exceeds the rated output of the fuel cell device by having the fuel cell device include a greater number of fuel cell units than the number of fuel cell units required for the rated output of the device guaranteed as a fuel cell device.

[0024] A fifth aspect of the prediction method of the present disclosure is the prediction method of the fourth aspect, wherein the output power of the fuel cell device may be a value obtained by multiplying the average value of the maximum output of each of the multiple fuel cell units by the number of fuel cell units included in the fuel cell device.

[0025] Each fuel cell unit deteriorates as the cumulative power generation time increases, causing a decrease in output voltage. The prediction method of this aspect can accurately determine the possible output power of the fuel cell device by calculating the average value of the maximum output of each fuel cell unit, which has decreased due to the decrease in output voltage, multiplied by the number of fuel cell units included in the fuel cell device.

[0026] The prediction method of the sixth aspect of the present disclosure may, in any one of the prediction methods of the first to fifth aspects, notify the display device of information suggesting adding a fuel cell unit to the fuel cell device, along with information indicating when the output power of the fuel cell device will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device.

[0027] In a seventh aspect of the prediction method of the present disclosure, in the sixth aspect of the prediction method, the information proposing the addition of fuel cell units may include information indicating the number of fuel cell units to be added in order to increase the output power of the fuel cell device to above a predetermined threshold.

[0028] As described above, the prediction method of this embodiment notifies the display device of information suggesting the addition of a fuel cell unit to the fuel cell device, allowing consumers to take measures such as adding a fuel cell unit in a timely manner.

[0029] The prediction device of the eighth aspect of the present disclosure includes a controller that predicts when the output power of a fuel cell device including a plurality of fuel cell units will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device, and a communicator that, under the control of the controller, notifies a display device of information indicating the above-mentioned time.

[0030] With this configuration, the prediction device of this aspect, unlike conventional examples, can appropriately predict the deterioration of a fuel cell device including multiple fuel cell units. Note that the details of the effects achieved by the prediction device of this aspect are similar to the effects achieved by the prediction method of the first aspect, and therefore will not be described here.

[0031] A power generation system according to a ninth aspect of the present disclosure includes the prediction device according to the eighth aspect and a fuel cell device including a plurality of fuel cell units.

[0032] With this configuration, the power generation system of this aspect, unlike conventional examples, can appropriately predict the deterioration of a fuel cell device including multiple fuel cell units. Note that the details of the effects achieved by the power generation system of this aspect are similar to the effects achieved by the prediction method of the first aspect, and therefore will not be described here.

[0033] Specific examples of the above-described aspects of the present disclosure will be described below with reference to the accompanying drawings. Each of the specific examples described below is an example of the above-described aspects of the present disclosure. Therefore, unless otherwise stated in the claims, the shapes, numerical values, components, arrangement positions and connection forms of the components shown below do not limit the scope of the claims.

[0034] Furthermore, among the components described below, components that are not described in the independent claims that represent the highest concept of the present disclosure are described as optional components. Furthermore, in the drawings, components with the same reference numerals may not be described in detail. The drawings are schematic illustrations of each component for ease of understanding, and the shapes, dimensional ratios, and the like may not be accurately depicted.

[0035] Furthermore, in the operation of the apparatus, the order of steps may be changed or known steps may be added as necessary.

[0036] (Embodiment) [Device Configuration] Fig. 1 is a diagram illustrating an example of a power generation system according to an embodiment. Fig. 2 is a diagram illustrating an example of a prediction device shown in Fig. 1.

[0037] The power generation system 10 of this embodiment includes a fuel cell device 15 including a plurality of fuel cell units, and a prediction device 20. As shown in FIG. 1, the power generation system 10 includes a group of fuel cell units a1-an, b1-bn, c1-cn, d1-dn, and e1-en. The power generation system 10 may be, for example, a system that supplies a large amount of power to an electric power grid. The configuration of the fuel cell device 15 in FIG. 1 will be described in more detail below.

[0038] The fuel cell unit group is made up of multiple fuel cell units a1-an, b1-bn, c1-cn, d1-dn, and e1-en. Although not shown, each of these fuel cell units a1-an, b1-bn, c1-cn, d1-dn, and e1-en is made up of a fuel cell stack, a power conditioner for converting DC power generated by the fuel cell stack into AC power and outputting it to the power grid, and a control device for controlling the operation of these devices.

[0039] In this example, the fuel cell unit groups are divided into fuel cell units a1-an belonging to fuel cell device 15A, fuel cell units b1-bn belonging to fuel cell device 15B, fuel cell units c1-cn belonging to fuel cell device 15C, fuel cell units d1-dn belonging to fuel cell device 15D, and fuel cell units e1-en belonging to fuel cell device 15E. All fuel cell units belonging to one group are also referred to simply as "fuel cell units in the group." For ease of explanation, fuel cell units a1-an, b1-bn, c1-cn, d1-dn, and e1-en may be abbreviated below as "fuel cell unit 15ij (i = a-e, j = 1-n)."

[0040] However, the above configuration of the fuel cell device 15 is merely an example and is not limited to this example. For example, the fuel cell device 15 may be a single group that includes multiple fuel cell units.

[0041] Control devices 30A to 30E are provided for each of groups A, B, C, D, and E, in other words, for each of fuel cell devices 15A to 15E, and control the operation of each of the fuel cell units within the group.

[0042] For example, the control device 30A controls the output of each of the fuel cell units a1 to an via a communication network to enable efficient operation (for example, optimization of the lifespan) of the fuel cell units a1 to an belonging to group A. Note that the fuel cell units may not be provided with control devices, and the operation of the fuel cell units belonging to each group may be directly controlled by the control devices 30A to 30E.

[0043] The control devices 30A to 30E may be any device that has a control function and includes an arithmetic processing unit (not shown), a memory unit (not shown) that stores a control program, and a communication device (not shown). The arithmetic processing unit reads and executes the control program stored in the memory unit, thereby performing predetermined control in the control devices 30A to 30E. An example of the arithmetic processing unit is a microprocessor. An example of the memory unit is a memory.

[0044] As shown in FIG. 2, the prediction device 20 includes a communicator 21 and a controller 23 .

[0045] The controller 23 predicts when the output power of the fuel cell device 15 including the fuel cell unit 15ij (i=a to e, j=1 to n) will fall below a predetermined threshold value equal to or greater than the rated output of the fuel cell device 15.

[0046] Here, "rated output of the fuel cell device 15" means the desired power guaranteed by the fuel cell device 15. Therefore, the fuel cell device 15 can output the desired power guaranteed by the fuel cell device 15 or power exceeding the desired power. An example of the latter configuration of the fuel cell device 15 will be described in the third embodiment.

[0047] Under the control of the controller 23, the communicator 21 notifies the display device 40 of information indicating when the power that can be output by the fuel cell device 15 will fall below a predetermined threshold that is equal to or greater than the rated output of the fuel cell device 15. This information may be, for example, a date on a calendar displayed on the display device 40. Examples of the "display device 40" include, but are not limited to, an information terminal of a consumer receiving the service of power supply generated by the power generation system 10, a display device of a maintenance company, etc. This allows consumers receiving the service of power supply generated by the power generation system 10 or maintenance workers of the fuel cell device 15 (hereinafter referred to as "consumers") to easily know when the power that can be output by the fuel cell device 15 will fall below a predetermined threshold that is equal to or greater than the rated output of the fuel cell device 15.

[0048] In this example, the controller 23 predicts the time when the power that can be output by the fuel cell device 15 will fall below a predetermined threshold that is equal to or greater than the rated output of the fuel cell device 15, but the present invention is not limited to this.

[0049] For example, a control device other than the controller 23 (for example, the control devices 30A to 30E) may predict the time when the power that can be output by the fuel cell device 15 will fall below a predetermined threshold that is equal to or greater than the rated output of the fuel cell device 15.

[0050] The controller 23 may be any device having a control function, and includes an arithmetic processing unit (not shown) and a storage unit (not shown) that stores a control program. The arithmetic processing unit reads and executes the control program stored in the storage unit, thereby performing predetermined control in the controller 23. An example of the arithmetic processing unit is a microprocessor. An example of the storage unit is a memory.

[0051] The above configuration of the power generation system 10 is merely an example and is not limited to this example. For example, the prediction device 20 may be integrated with the control devices 30A to 30E, in other words, equipped with the control functions of the control devices 30A to 30E, and directly control the operation of each of the fuel cell units in the group.

[0052] [Operation] Fig. 3 is a flowchart showing an example of the operation (prediction method) of the prediction device in the power generation system of the embodiment. The following operation may be performed, for example, by the calculation processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not necessarily required that the following operation be performed by the controller 23. An operator may perform some of the operation. In the following example, a case where the operation is controlled by the controller 23 will be described.

[0053] When the prediction device 20 starts operating, in step S1, it predicts the time when the outputtable power of the fuel cell device 15 including the fuel cell unit 15ij (i = a to e, j = 1 to n) will fall below a predetermined threshold equal to or greater than the rated output of the fuel cell device 15. Then, in step S2, information indicating the time of step S1 is notified to the display device 40.

[0054] The prediction of the timing may be based on a prediction of a decrease in the power outputtable of the fuel cell device due to deterioration of the fuel cell unit. Details will be explained in the first embodiment. As the cumulative power generation time of the fuel cell unit increases, the fuel cell unit deteriorates and the output voltage decreases. This decrease in the output voltage of the fuel cell unit reduces the maximum output of the fuel cell unit, and as a result, the outputtable power of the fuel cell device also decreases.

[0055] Furthermore, when predicting the timing, the proportion R of the period during which the fuel cell unit 15ij (i = a to e, j = 1 to n) is generating electricity during a predetermined period may be taken into consideration. The details of this proportion R will be explained in the second embodiment.

[0056] According to the present embodiment described above, unlike the conventional example, it is possible to appropriately predict the deterioration of the fuel cell device 15 including the fuel cell units 15ij (i=a to e, j=1 to n).

[0057] Specifically, in this embodiment, the power outputtable of the fuel cell device 15 including fuel cell units 15ij (i = a to e, j = 1 to n) is compared with the rated output guaranteed for the device. This makes it possible to notify the display device 40 of information indicating when the power outputtable of the fuel cell device 15 will fall below a predetermined threshold equal to or greater than the rated output. This allows consumers to take timely measures, such as replacing or adding fuel cell units, to prevent the power outputtable of the fuel cell device 15 from falling below the rated output, compared to when such information is not notified.

[0058] (First Example) Fig. 4 is a flowchart showing an example of the operation (prediction method) of the prediction device in the power generation system of the embodiment. Fig. 5 is a diagram for explaining an example of an approximate straight line showing the correlation between the average value of the cumulative power generation time of each fuel cell unit and the outputtable power of the fuel cell device calculated from the average value of the maximum output of each fuel cell unit corresponding to this average value of the cumulative power generation time. Fig. 6 is a diagram showing an example of the voltage stabilization timing when the voltage stabilizes after a predetermined time has elapsed since the fuel cell unit started generating power.

[0059] The following operations may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not essential that the following operations be performed by the controller 23. An operator may perform some of the operations. In the following example, a case where the operations are controlled by the controller 23 will be described.

[0060] When the prediction device 20 starts operating, in step S1A, it predicts the time TA at which the fuel cell device 15 will fall below a predetermined threshold W1 that is equal to or greater than the rated output, based on a prediction of a decrease in the power that can be output by the fuel cell device 15 due to deterioration of the fuel cell unit 15ij (i = a to e, j = 1 to n) (see FIG. 5 ). Then, in step S2A, information indicating the time TA in step S1A is notified to the display device 40.

[0061] Specifically, as shown in Fig. 5, an approximate line L is derived which shows the correlation between the average value T of the cumulative power generation time of each fuel cell unit 15ij (i = a to e, j = 1 to n) and the power that can be output by the fuel cell device 15, which is calculated from the average value WU of the maximum output of each fuel cell unit 15ij (i = a to e, j = 1 to n) that corresponds to this average value T of cumulative power generation time. In other words, the "power that can be output (maximum output) of the fuel cell device 15" in Fig. 5 is the value obtained by multiplying the average value WU of the maximum output by the "number of fuel cell units 15ij (i = a to e, j = 1 to n) included in the fuel cell device 15," which will be described later.

[0062] That is, since it is generally known that as the cumulative power generation time of each fuel cell unit increases, degradation of the fuel cell unit causes a decrease in the output voltage of the fuel cell unit, the approximate line L can be obtained based on the average values ​​(known data) indicated by the circles in Figure 5. Then, from the approximate line L and the predetermined threshold value W1, the time TA at which the power that can be output by the fuel cell device 15 falls below the predetermined threshold value W1, which is equal to or greater than the rated output of the fuel cell device 15, can be derived.

[0063] Here, the "average value WU of the maximum output of each fuel cell unit 15ij (i = a to e, j = 1 to n)" may be derived from known data regarding the voltage and current during a time period [ta, tb] between time ta and time tb, a predetermined time period after the start of power generation by each fuel cell unit 15ij (i = a to e, j = 1 to n). As shown in FIG. 6 , the time period [ta, tb] is an appropriate voltage stabilization timing during which the voltage stabilizes after a predetermined time period has elapsed since the start of power generation in rated operation. Therefore, the voltage and current may be the average values ​​of the voltage and current during the time period [ta, tb]. The time period between time ta and time tb may be, for example, approximately 30 minutes, but is not limited to this. The known data is data regarding the time from when the power generation time of each fuel cell unit 15ij (i = a to e, j = 1 to n) began at "zero" to the current cumulative power generation time, and is stored in the memory of the prediction device 20.

[0064] According to the present embodiment described above, the maximum output, which will decrease over the course of future cumulative power generation time, is predicted from the transition of the power (maximum output) that the fuel cell device 15 can output over the cumulative power generation time of the fuel cell device 15. The cumulative power generation time at which this predicted maximum output reaches the threshold value W1 can be appropriately derived as the time TA at which the power that the fuel cell device can output will fall below the threshold value W1.

[0065] The prediction method, prediction device 20, and power generation system 10 of this example may be the same as those of the embodiment except for the above-mentioned features.

[0066] Second Example Fig. 7 is a flowchart showing an example of the operation (prediction method) of the prediction device in the power generation system of the second example of the embodiment. The following operations may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not necessarily required that the following operations be performed by the controller 23. An operator may perform some of the operations. In the following example, a case where the operations are controlled by the controller 23 will be described.

[0067] When the operation of the prediction device 20 begins, in step S1B, the time TB at which the output power of the fuel cell device 15 including the fuel cell unit 15ij (i = a to e, j = 1 to n) will fall below a predetermined threshold value equal to or greater than the rated output of the fuel cell device 15 is predicted based on the cumulative power generation time of the fuel cell device 15 at which the output power of the fuel cell device 15 is predicted to fall below a predetermined threshold value equal to or greater than the rated output of the fuel cell device 15 and the proportion R of the period during which the fuel cell device 15 is generating power within the predetermined period. Then, in step S2B, information indicating the time TB of step S1B is notified to the display device 40.

[0068] Here, the "period ratio R" corresponds to the operating rate, which can be calculated, for example, by the following formula (1): "Operating rate" = "average cumulative power generation time of fuel cell unit 15ij (i = a to e, j = 1 to n)" / "average cumulative power supply time of fuel cell unit 15ij (i = a to e, j = 1 to n)" (1)

[0069] In formula (1), the "average cumulative power generation time of fuel cell units 15ij (i = a to e, j = 1 to n)" can be derived by dividing the total cumulative power generation time of each fuel cell unit 15ij (i = a to e, j = 1 to n) by the number of fuel cell units 15ij (i = a to e, j = 1 to n). Also, the "average cumulative power-on time of fuel cell units 15ij (i = a to e, j = 1 to n)" can be derived by dividing the total cumulative power-on time of each fuel cell unit 15ij (i = a to e, j = 1 to n) by the number of fuel cell units 15ij (i = a to e, j = 1 to n).

[0070] Therefore, as an example, in step S1B, when the "cumulative power generation time of the fuel cell device 15 at which the power output is predicted to fall below a predetermined threshold equal to or greater than the rated output of the fuel cell device 15" is considered to be, for example, "the time corresponding to time TA in FIG. 5," the "time TB at which the power outputtable of the fuel cell device 15 will fall below a predetermined threshold equal to or greater than the rated output of the fuel cell device" can be derived, for example, using the following equations (2) and (3): "cumulative power-on time of the fuel cell device 15 at which the power outputtable of the fuel cell device 15 is predicted to fall below a predetermined threshold equal to or greater than the rated output of the fuel cell device" = "time corresponding to time TA in FIG. 5" / "operation rate" (2) "time TB at which the power outputtable of the fuel cell device 15 will fall below a predetermined threshold equal to or greater than the rated output of the fuel cell device" = "current date" + "cumulative power-on time [h] of equation (2)" - "average cumulative power-on time [h] of the current fuel cell unit 15ij (i = a to e, j = 1 to n)" (3)

[0071] According to the present embodiment described above, it is possible to predict more accurately than ever before the time TB when the power that the fuel cell device 15 can output falls below a predetermined threshold that is equal to or greater than the rated output of the fuel cell device 15.

[0072] Specifically, if the fuel cell units 15ij (i = a to e, j = 1 to n) are used approximately evenly over a given period of time, the utilization rate of each fuel cell unit ij (i = a to e, j = 1 to n) will be approximately equal to the above-mentioned operating rate. Furthermore, the higher the utilization rate of a fuel cell unit 15ij (i = a to e, j = 1 to n), the faster the deterioration of that fuel cell unit 15ij (i = a to e, j = 1 to n) will progress.

[0073] As described above, according to this embodiment, by taking the above-mentioned operating rate into consideration when predicting the time TB when the output power of the fuel cell device 15 will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device 15, it is possible to more accurately predict the time when the output power of the fuel cell device 15 will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device 15, compared to when such operating rate is not taken into consideration.

[0074] However, the above prediction method is merely an example and is not limited to this example. For example, the "period ratio R" may be calculated based on the number of fuel cell devices 15, as shown in FIG.

[0075] Specifically, the unit number operating rate of the fuel cell device 15 means the ratio of the total number of fuel cell units 15ij (i = a to e, j = 1 to n) that are judged to "require power generation" in each time zone TS during a specified period to the total number of fuel cell units 15ij (i = a to e, j = 1 to n) that "require power generation" in each time zone TS, assuming that all fuel cell units 15ij (i = a to e, j = 1 to n) of the fuel cell device 15 "require power generation" in all time zones during a specified period.

[0076] In other words, the unit number operating rate of the fuel cell device 15 is obtained from the cumulative value of the number of fuel cell units 15ij (i = a to e, j = 1 to n) that require power generation in each time period TS and the cumulative value of the number of all fuel cell units 15ij (i = a to e, j = 1 to n) in each time period TS, and this unit number operating rate corresponds to the ``period ratio R.''

[0077] The prediction method, prediction device 20, and power generation system 10 of this example may be the same as those of the embodiment or the first example of the embodiment, except for the above-mentioned features.

[0078] (Third Example) The prediction method of the third example of the embodiment is the same as the prediction method of the embodiment, except that the fuel cell device 15 includes a greater number of fuel cell units 15ij (i = a to e, j = 1 to n) than the number of fuel cell units 15ij (i = a to e, j = 1 to n) required for the rated output of the fuel cell device 15, which is calculated from the rated output of the fuel cell units 15ij (i = a to e, j = 1 to n).

[0079] According to the present embodiment described above, the fuel cell device 15 includes a greater number of fuel cell units 15ij (i = a to e, j = 1 to n) than the number of fuel cell units required for the rated output guaranteed by the fuel cell device 15, thereby appropriately realizing that the power that can be output by the fuel cell device 15 exceeds the rated output of the fuel cell device 15.

[0080] The prediction method, prediction device 20, and power generation system 10 of this example may be the same as any of the first and second examples of the embodiment, except for the above-mentioned features.

[0081] (Fourth Example) The prediction method of the fourth example of the embodiment is the same as the prediction method of the embodiment, except that the output power of the fuel cell device 15 is the average value WU of the maximum output of each fuel cell unit 15ij (i = a to e, j = 1 to n) multiplied by the number of fuel cell units 15ij (i = a to e, j = 1 to n) included in the fuel cell device 15.

[0082] Here, as described in the second embodiment, the "average value WU of the maximum output of each fuel cell unit 15ij (i = a to e, j = 1 to n)" may be derived from known data regarding the voltage and current during the time period [ta, tb] between time ta and time tb, a predetermined time period after the start of power generation by each fuel cell unit 15ij (i = a to e, j = 1 to n). As shown in FIG. 6 , the time period [ta, tb] is an appropriate voltage stabilization timing during which the voltage stabilizes after a predetermined time period has elapsed since the start of power generation in rated operation. Therefore, the voltage and current may be the average values ​​of the voltage and current during the time period [ta, tb]. The time period between time ta and time tb may be, for example, approximately 30 minutes, but is not limited to this. The known data is data regarding the time from when the power generation time of each fuel cell unit 15ij (i = a to e, j = 1 to n) began at "zero" to the current cumulative power generation time, and is stored in the memory unit of the prediction device 20.

[0083] Furthermore, "the number of fuel cell units 15ij (i = a to e, j = 1 to n) included in the fuel cell device 15" includes the number of backup fuel cell units that are used to maintain the rated output of the fuel cell device 15 guaranteed by the total output of the fuel cell units 15ij (i = a to e, j = 1 to n) that are generating electricity, but does not include the number of backup fuel cell units that replace fuel cell units that are not currently cooled.

[0084] According to the present embodiment described above, each of the fuel cell units 15ij (i = a to e, j = 1 to n) deteriorates and its voltage drops as the cumulative power generation time increases. The prediction method of this embodiment calculates the power that can be output by the fuel cell device 15 by multiplying the average value WU of the maximum output of the fuel cell units 15ij (i = a to e, j = 1 to n) that has decreased due to a decrease in output voltage by the number of fuel cell units 15ij (i = a to e, j = 1 to n) included in the fuel cell device 15, thereby making it possible to accurately determine the power that can be output by the fuel cell device 15.

[0085] The prediction method, prediction device 20, and power generation system 10 of this example may be the same as any of the first to third examples of the embodiment, except for the above-mentioned features.

[0086] Fifth Example Fig. 9 is a flowchart showing an example of the operation (prediction method) of the prediction device in the power generation system of the fifth example of the embodiment. The following operations may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not necessarily required that the following operations be performed by the controller 23. An operator may perform some of the operations. In the following example, a case where the operations are controlled by the controller 23 will be described.

[0087] Steps S1 and S2 in FIG. 9 are similar to steps S1 and S2 in FIG. 3, respectively, and therefore will not be described in detail.

[0088] Along with or after the operation of step S2, in step S3, information proposing the addition of a fuel cell unit to the fuel cell device 15 is notified to the display device 40.

[0089] Here, the "information proposing to add fuel cell units to the fuel cell device 15" may include information indicating the number of fuel cell units to be added in order to increase the output power of the fuel cell device 15 to a predetermined threshold or more. In this case, when the output power of the fuel cell device 15 is to be increased to a power corresponding to an arbitrary set value S that is equal to or greater than the predetermined threshold, the "number of fuel cell units to be added" can be derived, for example, by the following formula (4): "number of fuel cell units to be added" = (set value S - predetermined threshold) / rated output of a single fuel cell unit (4)

[0090] The set value S may be set to be greater than a predetermined threshold value so that the value of the numerator on the right side of equation (4) is an integer multiple of the rated output of a single fuel cell unit. For example, if the rated output of a single fuel cell unit is 5 kW, the rated output of the fuel cell device 15 is 100 kW, and the predetermined threshold is 100 kW, the set value S is set to a value that can be divided into two or three when calculating the number of additional fuel cell units in equation (4), such as 110 kW or 115 kW.

[0091] According to the present embodiment described above, information suggesting the addition of a fuel cell unit to the fuel cell device 15 is notified to the display device 40, allowing consumers to take measures such as adding a fuel cell unit at the appropriate time.

[0092] The prediction method, prediction device 20, and power generation system 10 of this example may be the same as any of the first to fourth examples of the embodiment, except for the above-mentioned features.

[0093] The first to fifth embodiments of the present disclosure may be combined with each other as long as they do not exclude each other. From the above description, many improvements and other embodiments of the present disclosure will be apparent to those skilled in the art. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present disclosure.

[0094] An aspect of the present disclosure can be used in a prediction method, a prediction device, and a power generation system that, unlike conventional examples, can appropriately predict the deterioration of a fuel cell device including a plurality of fuel cell units.

[0095] 10: Power generation system 15: Fuel cell device 15A: Fuel cell device 15B: Fuel cell device 15C: Fuel cell device 15D: Fuel cell device 15E: Fuel cell device 20: Prediction device 21: Communication device 23: Controller 30A: Control device 30B: Control device 30C: Control device 30D: Control device 30E: Control device 40: Display device a1 to an: Fuel cell unit b1 to bn: Fuel cell unit c1 to cn: Fuel cell unit d1 to dn: Fuel cell unit e1 to en: Fuel cell unit

Claims

1. A prediction method comprising the steps of: predicting when the output power of a fuel cell device including a plurality of fuel cell units will fall below a predetermined threshold value that is equal to or greater than the rated output of the fuel cell device; and notifying a display device of information indicating the time.

2. The prediction method according to claim 1, wherein the time is predicted based on a prediction of a decrease in the outputtable power of the fuel cell device due to deterioration of the fuel cell unit.

3. A prediction method as described in claim 1 or 2, which predicts the time when the output power of the fuel cell device is predicted to fall below the specified threshold value based on the cumulative power generation time of the fuel cell device and the proportion of the period during which the fuel cell unit is generating power during a specified period.

4. A prediction method described in any one of claims 1 to 3, wherein the fuel cell device includes a greater number of fuel cell units than the number of fuel cell units required for the rated output of the fuel cell device calculated from the rated output of the fuel cell units.

5. The prediction method according to claim 4, wherein the outputtable electric power of the fuel cell device is a value obtained by multiplying the average value of the maximum output of each of the plurality of fuel cell units by the number of the fuel cell units included in the fuel cell device.

6. A prediction method according to any one of claims 1 to 5, further comprising the step of notifying said display device of information suggesting the addition of said fuel cell unit to said fuel cell device together with information indicating said time.

7. The prediction method described in claim 6, wherein the information proposing the addition of the fuel cell unit includes information indicating the number of fuel cell units to be added in order to increase the output power of the fuel cell device to above the specified threshold.

8. A prediction device comprising: a controller that predicts when the outputtable power of a fuel cell device including a plurality of fuel cell units will fall below a predetermined threshold value that is equal to or higher than the rated output of the fuel cell device; and a communication device that, under the control of the controller, notifies a display device of information indicating the time.

9. A power generation system comprising: the prediction device according to claim 8; and a fuel cell device including a plurality of fuel cell units.

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