Method for predicting residual amount of hydrogen tank, device for predicting residual amount of hydrogen tank, and power generation system

Abstract

A method for predicting the residual amount of a hydrogen tank according to the present disclosure is used in a fuel cell device including at least one fuel cell unit. The method comprises: a step for predicting a time when the residual hydrogen amount of the hydrogen tank becomes smaller than or equal to a first threshold on the basis of the hydrogen amount of the hydrogen tank used in a first period over a plurality of days; and a step of notifying a display device of the time. When the hydrogen amount of the hydrogen tank used in a second period over a plurality of days within the first period is smaller than or equal to a second threshold, the time is predicted on the basis of the hydrogen amount of the hydrogen tank used in a period excluding the second period in the first period.

Description

Method for predicting remaining hydrogen tank capacity, device for predicting remaining hydrogen tank capacity, and power generation system

[0001] The present disclosure relates to a method for predicting remaining hydrogen tank capacity, a device for predicting remaining hydrogen tank capacity, and a power generation system.

[0002] Patent Document 1 discloses an apparatus for generating an operation plan for a hydrogen production system equipped with a hydrogen generation device, the apparatus comprising: a demand prediction unit that generates a predicted demand amount for each of multiple types of hydrogen whose production has different environmental loads during the period covered by the operation plan; and an operation planning unit that generates an operation plan for generating multiple types of hydrogen whose production has different environmental loads using the hydrogen generation device based on the predicted hydrogen demand amount for each of the multiple types of hydrogen.

[0003] International Publication No. 2020 / 203520

[0004] As an example, the present disclosure aims to provide a hydrogen tank remaining capacity prediction method, a hydrogen tank remaining capacity prediction device, and a power generation system that can more accurately predict when the remaining hydrogen capacity in a hydrogen tank used in a fuel cell device will fall below a predetermined amount.

[0005] In order to solve the above problem, one aspect of the present disclosure is a method for predicting the remaining amount of hydrogen in a hydrogen tank used in a fuel cell device including at least one fuel cell unit, comprising the steps of predicting when the remaining amount of hydrogen in the hydrogen tank will be below a first threshold based on the amount of hydrogen in the hydrogen tank used during a first period spanning multiple days, and notifying a display device of the time, wherein when the amount of hydrogen in the hydrogen tank used during a second period spanning multiple days within the first period is below a second threshold, the time is predicted based on the amount of hydrogen in the hydrogen tank used during a period of the first period excluding the second period.

[0006] Another aspect of the present disclosure is a hydrogen tank remaining amount prediction device used in a fuel cell device including at least one fuel cell unit, comprising: a controller that predicts when the remaining hydrogen amount in the hydrogen tank will be below a first threshold based on the amount of hydrogen in the hydrogen tank used during a first period spanning multiple days; and a communicator that is controlled by the controller and notifies a display device of the time, wherein when the amount of hydrogen in the hydrogen tank used during a second period spanning multiple days within the first period is below a second threshold, the controller predicts the time based on the amount of hydrogen in the hydrogen tank used during a period of the first period excluding the second period.

[0007] A power generation system according to one aspect of the present disclosure includes a fuel cell device including at least one fuel cell unit, and the hydrogen tank remaining amount prediction device described above.

[0008] The hydrogen tank remaining amount prediction method, hydrogen tank remaining amount prediction device, and power generation system of one embodiment of the present disclosure have the effect of being able to predict more accurately than conventional methods when the remaining hydrogen amount in a hydrogen tank used in a fuel cell device will fall below a predetermined amount.

[0009] FIG. 1 is a diagram showing an example of a power generation system according to a first embodiment. FIG. 2A is a diagram showing an example of a sensor for calculating the remaining amount of hydrogen in a hydrogen tank. FIG. 2B is a diagram showing an example of a sensor for calculating the remaining amount of hydrogen in a hydrogen tank. FIG. 2C is a diagram showing an example of a sensor for calculating the remaining amount of hydrogen in a hydrogen tank. FIG. 3 is a flowchart showing an example of the operation of a hydrogen tank remaining amount prediction device (a method for predicting the remaining amount of hydrogen in a hydrogen tank) according to the first embodiment. FIG. 4 is a flowchart showing an example of the operation of a hydrogen tank remaining amount prediction device (a method for predicting the remaining amount of hydrogen in a hydrogen tank) according to a first example of the first embodiment. FIG. 5 is a diagram showing an example of a power generation system according to a second embodiment.

[0010] As a result of thorough research into predicting when the remaining hydrogen level in a hydrogen tank used in a fuel cell device will fall below a predetermined threshold, the present inventors discovered that excluding data from a period in which the amount of hydrogen used in the hydrogen tank is irregularly lower than the normal amount of hydrogen used over several days when calculating the amount of hydrogen used in the hydrogen tank can result in a more appropriate calculation of the amount of hydrogen used than if this were not done, and they came up with the following aspect of the present disclosure.

[0011] In other words, a first aspect of the present disclosure is a method for predicting the remaining amount of hydrogen in a hydrogen tank used in a fuel cell device including at least one fuel cell unit, comprising the steps of predicting when the remaining amount of hydrogen in the hydrogen tank will be below a first threshold based on the amount of hydrogen in the hydrogen tank used during a first period spanning multiple days, and notifying a display device of this time, wherein when the amount of hydrogen in the hydrogen tank used during a second period spanning multiple days within the first period is below the second threshold, the time is predicted based on the amount of hydrogen in the hydrogen tank used during a period of the first period excluding the second period.

[0012] As described above, the method for predicting the remaining amount of hydrogen in a hydrogen tank according to this aspect can predict the time when the remaining amount of hydrogen in a hydrogen tank used in a fuel cell device will fall below the first threshold more accurately than conventional methods.

[0013] Specifically, excluding data from a second period during which hydrogen usage from the hydrogen tank is irregularly lower than normal hydrogen usage over multiple days can result in a more accurate calculation of hydrogen usage than if data from the second period were not included. Therefore, the hydrogen tank remaining capacity prediction method of this aspect predicts when the remaining hydrogen level in the hydrogen tank will fall below the first threshold based on the amount of hydrogen used in the hydrogen tank during the first period excluding the second period, thereby improving the accuracy of the prediction compared to not including such an excluded period in the hydrogen usage calculation. This allows the user to refill the hydrogen tank with hydrogen or replace the hydrogen tank in use with a new one in a timely manner.

[0014] Furthermore, in the method for predicting remaining hydrogen in a hydrogen tank of this embodiment, by setting each of the first and second periods to span multiple days, the prediction of when the remaining hydrogen in the hydrogen tank will fall below the first threshold is less affected by fluctuations in the amount of hydrogen used in daily activities. For example, the amount of hydrogen used on specific days such as holidays is generally less than on weekdays, but in the method for predicting remaining hydrogen in a hydrogen tank of this embodiment, by setting the first and second periods as described above, the influence of daily fluctuations in the amount of hydrogen used is reduced in the prediction of when the remaining hydrogen in the hydrogen tank will fall below the first threshold.

[0015] The second aspect of the hydrogen tank remaining capacity prediction method of the present disclosure is different from the first aspect of the hydrogen tank remaining capacity prediction method in that when the first period and the second period are the same, it is not necessary to update the time when the remaining hydrogen in the hydrogen tank will be below the first threshold.

[0016] Here, "the first period and the second period are the same" means that the amount of hydrogen used in the hydrogen tank is irregularly low compared to the normal amount of hydrogen used throughout the entire first period. Therefore, when the first period and the second period are the same, the method for predicting the remaining amount of hydrogen in a hydrogen tank of this aspect does not update the time when the remaining amount of hydrogen in the hydrogen tank used in the fuel cell device will be below the first threshold, thereby making it possible to efficiently predict this time.

[0017] A third aspect of the present disclosure is a hydrogen tank remaining amount prediction method, which, in the hydrogen tank remaining amount prediction method of the first or second aspect, may predict when the remaining hydrogen amount in the hydrogen tank will be below the first threshold value based on the difference between the remaining hydrogen amount in the hydrogen tank and the first threshold value divided by the average daily amount of hydrogen used during the first period excluding the second period.

[0018] As described above, the present method for predicting the remaining amount of hydrogen in a hydrogen tank predicts the time when the remaining amount of hydrogen in the hydrogen tank will be below the first threshold value based on the difference between the remaining amount of hydrogen in the hydrogen tank and the first threshold value divided by the average daily amount of hydrogen used during the period of the first period excluding the second period, thereby improving the accuracy of the prediction compared to when no exclusion period is set in calculating the amount of hydrogen used.

[0019] A fourth aspect of the present disclosure is a method for predicting the remaining amount of hydrogen in a hydrogen tank, in any one of the first to third aspects, wherein the first period may be one week or multiple weeks, and the second period may be a number of weeks shorter than the first period.

[0020] According to the above, in the method for predicting remaining hydrogen in a hydrogen tank of this aspect, by setting the first period and the second period to one week or multiple weeks, and the second period to a number of weeks less than the first period, respectively, the prediction of when the remaining hydrogen in the hydrogen tank will fall below the first threshold is less affected by fluctuations in the amount of hydrogen used in daily activities. For example, the amount of hydrogen used during certain periods of the week (e.g., weekends) is generally less than during weekdays, but by setting the first period and the second period as described above, the method for predicting remaining hydrogen in a hydrogen tank of this aspect reduces the influence of daily fluctuations in hydrogen use that occur over the course of a week on the prediction of when the remaining hydrogen in the hydrogen tank will fall below the first threshold.

[0021] A fifth aspect of the present disclosure is a hydrogen tank remaining amount prediction device used in a fuel cell device including at least one fuel cell unit, comprising: a controller that predicts when the remaining hydrogen amount in the hydrogen tank will be below a first threshold based on the amount of hydrogen in the hydrogen tank used during a first period spanning multiple days; and a communicator that is controlled by the controller and notifies a display device of the time, wherein when the amount of hydrogen in the hydrogen tank used during a second period spanning multiple days within the first period is below the second threshold, the controller predicts the time based on the amount of hydrogen in the hydrogen tank used during a period of the first period excluding the second period.

[0022] As described above, the hydrogen tank remaining amount prediction device of this aspect can predict more accurately than conventional methods when the remaining amount of hydrogen in a hydrogen tank used in a fuel cell system will fall below the first threshold. Note that the details of the effects achieved by the hydrogen tank remaining amount prediction device of this aspect are similar to the effects achieved by the hydrogen tank remaining amount prediction method of the first aspect, and therefore will not be described here.

[0023] A power generation system according to a sixth aspect of the present disclosure includes a fuel cell device including at least one fuel cell unit, and the hydrogen tank remaining amount prediction device according to the fifth aspect.

[0024] As a result, the power generation system of this aspect can predict more accurately than conventional methods when the remaining hydrogen level in a hydrogen tank used in a fuel cell device will fall below the first threshold. Note that the detailed effects of the power generation system of this aspect are similar to those of the first aspect of the method for predicting the remaining hydrogen level in a hydrogen tank, and therefore will not be described here.

[0025] 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.

[0026] 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.

[0027] Furthermore, in the operation of the apparatus, the order of steps may be changed or known steps may be added as necessary.

[0028] First Embodiment [Device Configuration] FIG. 1 is a diagram showing an example of a power generation system according to a first embodiment.

[0029] As shown in FIG. 1, the power generation system 10 includes a fuel cell device 15 and a remaining amount prediction device 20 for a hydrogen tank 40 used in the fuel cell device 15 .

[0030] The fuel cell device 15 includes at least one fuel cell unit that generates power using hydrogen from the hydrogen tank 40. Therefore, the fuel cell device 15 may include a single fuel cell unit, or multiple fuel cell units. In the latter case, the power generation system 10 may be, for example, a system that supplies large amounts of power to an electric power grid. That is, in the latter case, the power generation system 10 includes a group of fuel cell units each consisting of multiple fuel cell units including a fuel cell stack, and the fuel cell device 15 corresponds to each group obtained by dividing the group of fuel cell units. The detailed configuration of such a power generation system 10 will be described in the second embodiment.

[0031] As shown in FIG. 1, the remaining amount predicting device 20 for a hydrogen tank 40 includes a communicator 21 and a controller 23 .

[0032] The controller 23 predicts when the remaining amount of hydrogen in the hydrogen tank 40 will be below threshold SA based on the amount of hydrogen in the hydrogen tank 40 used over a period A spanning multiple days. Furthermore, when the amount of hydrogen in the hydrogen tank used over a period B spanning multiple days within period A is below threshold SB, the controller 23 predicts when the remaining amount of hydrogen in the hydrogen tank 40 will be below threshold SA based on the amount of hydrogen in the hydrogen tank used over a period of period A excluding period B. A specific example of a method for calculating "when the remaining amount of hydrogen in the hydrogen tank 40 will be below threshold SA" will be described in the first embodiment.

[0033] Here, the "multiple days" in "period A" may be a few days, or may be a longer period selected from a range of one week (7 days) to several months. For example, "period A" may be a period of weeks selected from a range of about two weeks to one month (4 weeks).

[0034] The "multiple days" in "period B" may be a few days, or may be any suitable number of days selected from a longer period of one week (7 days) to one month. For example, "period B" may be one week (7 days), but is at least a period shorter than "period A."

[0035] The "threshold SA" is an appropriate amount of hydrogen that is preset by the user, and corresponds to a reference value for prompting the user to refill hydrogen into the hydrogen tank 40 when the amount of hydrogen remaining in the hydrogen tank 40 is low, or for prompting the user to replace the hydrogen tank 40 currently in use with a new hydrogen tank. The "threshold SA" may be set to, for example, an amount of hydrogen that is approximately 20% of the amount of hydrogen when the hydrogen tank 40 is fully charged, but is not limited to this.

[0036] The "threshold value SB" is an appropriate amount of hydrogen preset by the user, and corresponds to a reference value assuming a situation in which the amount of hydrogen used in the hydrogen tank 40 used during period B is irregularly small compared to the normal amount of hydrogen used. For example, the "threshold value SB" may be set to an amount of hydrogen that is approximately 10% of the amount of hydrogen when the hydrogen tank 40 is fully charged, but is not limited to this.

[0037] The "situation in which the amount of hydrogen used in the hydrogen tank during period B is irregularly small compared to the normal amount of hydrogen used" can occur due to various factors. For example, the situation may occur due to some unusual behavior by the user. Furthermore, the situation may also occur when the amount of hydrogen used in the hydrogen tank 40 cannot be measured correctly. Furthermore, the situation may also occur when the power generation system 10 cannot generate power correctly.

[0038] As described above, the above situation is one in which the amount of hydrogen used is irregularly small compared to the normal amount of hydrogen used, and therefore does not include a case in which the operation of the power generation system 10 is periodically suspended for multiple days. For example, the above situation does not include a case in which the operation of the power generation system 10 is suspended on Saturdays and Sundays every week. In such a case, period B is set to include the suspension period and to be a period longer than the suspension period (for example, one week), and a threshold value SB is set for this period B to determine whether or not it corresponds to the above situation.

[0039] The controller 23 may be any device having a control function, and may include an arithmetic processing unit (not shown) and a storage unit 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. The controller 23 may directly control the operation, including the output, of the fuel cell unit in the fuel cell device 15. Furthermore, if a control device (not shown) that controls the operation of the fuel cell unit itself is provided in the fuel cell unit, the controller 23 may indirectly control the operation, including the output, of the fuel cell unit in the fuel cell device 15 via the control device.

[0040] The communicator 21 is a transmitter that is controlled by the controller 23 and notifies the display device 50 of information indicating when the remaining amount of hydrogen in the hydrogen tank 40 will fall below the threshold SA. The display device 50 may be, for example, an information terminal of a user who receives the service of supplying electric power generated by the power generation system 10, but is not limited to this.

[0041] Here, the remaining amount of hydrogen in the hydrogen tank 40 may be measured, for example, by an appropriate sensor. The measurement by such a sensor is performed at predetermined time intervals by the processing unit of the controller 23, and the measurement data of the sensor is sequentially stored in the memory unit of the controller 23. This "predetermined time" may be, for example, about 30 seconds, but is not limited to this.

[0042] For example, as shown in FIG. 2A , a hydrogen supply source for the fuel cell device 15 may include a liquid hydrogen tank 40A for hydrogen replenishment and a hydrogen gas tank 41 for storing the liquid hydrogen in the liquid hydrogen tank 40A as low-pressure hydrogen gas. In this case, the liquid hydrogen tank 40A corresponds to the “hydrogen tank” of the present disclosure, and the remaining amount of hydrogen in the liquid hydrogen tank 40A may be calculated by the controller 23, for example, from measurement data of a liquid level sensor 42 provided in the liquid hydrogen tank 40A. The remaining amount of hydrogen in the liquid hydrogen tank 40A may also be calculated by the controller 23 from measurement data of a flow meter 43 provided in a hydrogen gas path for supplying hydrogen gas from the hydrogen gas tank 41 to the fuel cell device 15. The measurement data of the liquid level sensor 42 or the flow meter 43 may be transmitted to the controller 23 via a controller (not shown) provided in the fuel cell device 15, or may be transmitted directly to the controller 23. The controller (not shown) provided in the fuel cell device 15 corresponds to the control device 30A, etc., described below.

[0043] 2B , hydrogen supply sources for the fuel cell device 15 may include a hydrogen gas tank 40B that stores high-pressure hydrogen gas for hydrogen replenishment and a hydrogen gas tank 41 that stores the high-pressure hydrogen gas in the hydrogen gas tank 40B as low-pressure hydrogen gas. In this case, the hydrogen gas tank 40B corresponds to the “hydrogen tank” of the present disclosure, and the remaining amount of hydrogen in the hydrogen gas tank 40B may be calculated by the controller 23, for example, from measurement data of a pressure gauge 44 provided in the hydrogen gas tank 40B. The remaining amount of hydrogen in the hydrogen gas tank 40B may also be calculated by the controller 23 from measurement data of a flow meter 43 provided in a hydrogen gas path for supplying hydrogen gas from the hydrogen gas tank 41 to the fuel cell device 15. The measurement data of the pressure gauge 44 or the flow meter 43 may be transmitted to the controller 23 via a controller (not shown) provided in the fuel cell device 15, or may be transmitted directly to the controller 23. The controller (not shown) provided in the fuel cell device 15 corresponds to a control device 30A, etc., described below.

[0044] 2C , a hydrogen gas tank 40C for storing low-pressure hydrogen gas for hydrogen replenishment may be provided as a hydrogen supply source for the fuel cell device 15. In this case, the hydrogen gas tank 40C corresponds to the “hydrogen tank” of the present disclosure, and the remaining amount of hydrogen in the hydrogen gas tank 40C may be calculated by the controller 23, for example, from measurement data of a pressure gauge 44 provided in the hydrogen gas tank 40C. The remaining amount of hydrogen in the hydrogen gas tank 40C may also be calculated by the controller 23 from measurement data of a flow meter 43 provided in a hydrogen gas path for supplying hydrogen gas from the hydrogen gas tank 40C to the fuel cell device 15. The measurement data of the pressure gauge 44 or the flow meter 43 may be transmitted to the controller 23 via a controller (not shown) provided in the fuel cell device 15, or may be transmitted directly to the controller 23. The controller (not shown) provided in the fuel cell device 15 corresponds to a control device 30A, etc., which will be described later.

[0045] The above-described configuration of the hydrogen supply source of the fuel cell device 15 is merely an example and is not limited to this example. The hydrogen supply source may be configured, for example, so that a hydrogen gas tank with a low amount of hydrogen can be replaced with a new hydrogen gas tank at appropriate times.

[0046] [Operation] Figure 3 is a flowchart showing an example of the operation of the hydrogen tank remaining amount prediction device (hydrogen tank remaining amount prediction method) in the first 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 memory 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.

[0047] First, at a predetermined timing, a setting file stored in advance in the memory unit of the controller 23 is read into the calculation processing unit of the controller 23. The "predetermined timing" may be set, for example, to at least once a week, but is not limited to this. The "setting file" stores, for example, time periods A and B set in advance by the user, and the type of hydrogen tank 40 (e.g., hydrogen gas tank, liquid hydrogen tank). Then, data such as the amount of hydrogen used in the hydrogen tank 40 during each of time periods A and B is obtained from the memory unit of the controller 23.

[0048] After the above operations are performed, in step S1, it is determined whether the amount of hydrogen in the hydrogen tank 40 used during a period B spanning multiple days within a period A spanning multiple days is less than or equal to a threshold value SB.

[0049] The determination in step S1 of "whether the amount of hydrogen used in hydrogen tank 40 during period B is equal to or less than threshold value SB" is not limited to being made by comparing the total amount of hydrogen used in hydrogen tank 40 during period B with threshold value SB. For example, the "determination" in step S1 may be made by comparing the average amount of hydrogen used in hydrogen tank 40 during period B (e.g., the average amount of hydrogen used per day) with threshold value SB set for the average amount of hydrogen used in hydrogen tank 40 during period B. Furthermore, the "determination" in step S1 may be made by comparing the average power generation output of the fuel cell unit, which indirectly correlates with the amount of hydrogen used in hydrogen tank 40 during period B, with threshold value SB set for the average power generation power of the fuel cell unit during period B.

[0050] Here, if the amount of hydrogen in the hydrogen tank 40 used during period B within period A is less than or equal to threshold value SB (if the answer is "Yes" in step S1), then in step S2, the time when the remaining amount of hydrogen in the hydrogen tank will be less than or equal to threshold value SA is predicted based on the amount of hydrogen in the hydrogen tank 40 used during period A excluding period B.

[0051] Next, in step S3, information indicating the time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA, as predicted in step S2, is notified to the display device 50 by the communication device 21. The time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA may be provided to the user as, for example, information on the year, month, and day on a calendar displayed on the display device 50. Furthermore, if the time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA is stored in the memory of the controller 23, the stored time may be updated with new data. Thereafter, the operations from step S1 onwards are executed again at the next specified timing.

[0052] On the other hand, if the amount of hydrogen in the hydrogen tank 40 used during period B within period A exceeds threshold value SB (if the answer is "No" in step S1), then in step S4, the time when the remaining amount of hydrogen in the hydrogen tank will fall below threshold value SA is predicted based on the amount of hydrogen in the hydrogen tank used during period A.

[0053] Next, in step S5, information indicating the time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA, as predicted in step S4, is notified to the display device 50 by the communication device 21. The time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA may be provided to the user as, for example, information on the year, month, and day on a calendar displayed on the display device 50. Furthermore, if the time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA is stored in the memory of the controller 23, the stored time may be updated with new data. Thereafter, the operations from step S1 onwards are executed again at the next specified timing.

[0054] According to the present embodiment described above, it is possible to predict more accurately than ever before when the remaining amount of hydrogen in the hydrogen tank 40 used in the fuel cell device 15 will fall below the threshold value SA.

[0055] Specifically, excluding data from period B, during which the amount of hydrogen used in the hydrogen tank 40 is irregularly lower than normal hydrogen usage over several days, can result in a more accurate calculation of hydrogen usage than if this data were not included. Therefore, this embodiment predicts when the remaining hydrogen level in the hydrogen tank 40 will fall below threshold SA based on the amount of hydrogen used in the hydrogen tank 40 during period A excluding period B, thereby improving the accuracy of the prediction compared to not including this exclusion period in the hydrogen usage calculation. This allows the user to refill the hydrogen tank 40 with hydrogen or replace the hydrogen tank 40 in use with a new one in a timely manner.

[0056] Furthermore, according to this embodiment, by setting each of Period A and Period B over multiple days, the prediction of when the remaining hydrogen level in the hydrogen tank 40 will fall below threshold SA is less affected by fluctuations in the amount of hydrogen used in daily activities. For example, the amount of hydrogen used on specific days such as holidays is generally less than on weekdays, but in this embodiment, by setting Period A and Period B as described above, the influence of daily fluctuations in the amount of hydrogen used on the prediction of when the remaining hydrogen level in the hydrogen tank 40 will fall below threshold SA is reduced.

[0057] (First Example) Figure 4 is a flowchart showing an example of the operation of the hydrogen tank remaining amount prediction device (method of predicting remaining amount of hydrogen tank) in a first example of the first 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 memory 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.

[0058] Note that step S1 in FIG. 4 is similar to step S1 in FIG. 3, and therefore a detailed description thereof will be omitted.

[0059] If the amount of hydrogen used in the hydrogen tank 40 during period B within period A is less than or equal to threshold value SB (if step S1 returns "Yes"), then in step S2A, the time when the amount of hydrogen remaining in the hydrogen tank 40 will be less than threshold value SA is predicted based on the difference between the remaining amount of hydrogen in the hydrogen tank 40 and threshold value SA divided by the average daily amount of hydrogen used during period A excluding period B.

[0060] For example, the average daily amount of hydrogen used during the period A excluding the period B (hereinafter referred to as the average hydrogen usage amount q1) is calculated by the following formula (1): q1 [Nm 3 (Normal Lube) / day] = (total amount of hydrogen used in period A excluding period B) / (number of days in period A - number of days in period B) (1)

[0061] The difference Q1 between the amount of hydrogen present in the hydrogen tank 40 and the amount of hydrogen corresponding to the threshold SA can be calculated from the measurement data of the pressure gauge 44 using the following equation (2): Q1 [Nm 3 ]=(current measurement data of the pressure gauge 44 [MPa]−threshold value SA [MPa])דpredetermined coefficient” (2)

[0062] Here, the "predetermined coefficient" is a numerical value that is preset by the user and is proportional to the size (volume) of the hydrogen tank 40, and is an appropriate value for converting the sensor's counting data into the remaining amount of hydrogen (normal lube) in the hydrogen tank 40.

[0063] Then, the number of days T1 until the remaining amount of hydrogen in the hydrogen tank 40 is predicted to reach the threshold value SA is obtained from the following equation (3): T1 [days]=Q1 / q1 (3)

[0064] As a result of the above, the time when the remaining amount of hydrogen in the hydrogen tank 40 will be equal to or less than the threshold value SA can be predicted from the number of days T1.

[0065] Next, in step S3A, information indicating the time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA, as predicted in step S2A, is notified to the display device 50 by the communication device 21. The time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA may be provided to the user as, for example, information on the year, month, and day on a calendar displayed on the display device 50. Furthermore, if the time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA is stored in the memory of the controller 23, the stored time may be updated with new data. Thereafter, the operations from step S1 onwards are executed again at the next specified timing.

[0066] On the other hand, if the amount of hydrogen used in the hydrogen tank 40 during period B within period A exceeds the threshold value SB (if the answer is "No" in step S1), then in step S4A, the time when the amount of hydrogen remaining in the hydrogen tank 40 will fall below the threshold value SA is predicted based on the difference between the amount of hydrogen remaining in the hydrogen tank 40 and the threshold value SA divided by the average amount of hydrogen used per day during period A.

[0067] For example, the average value q2 of the amount of hydrogen used per day during period A (hereinafter referred to as the average amount of hydrogen used q2) is calculated by the following formula (4): q2 [Nm 3 (Normal Lube) / day] = (total amount of hydrogen used in period A) / (number of days in period A) (4)

[0068] Furthermore, the difference Q2 between the amount of hydrogen present in the hydrogen tank 40 and the amount of hydrogen corresponding to the threshold SA can be calculated from the measurement data of the pressure gauge 44 using the following equation (5): Q2 [Nm 3 ]=(current measurement data of pressure gauge 44 [MPa]−threshold SA [MPa])דpredetermined coefficient” (5)

[0069] Here, the "predetermined coefficient" is a numerical value that is preset by the user and is proportional to the size (volume) of the hydrogen tank 40, and is an appropriate value for converting the sensor's counting data into the remaining amount of hydrogen (normal lube) in the hydrogen tank 40.

[0070] Then, the number of days T2 until the remaining amount of hydrogen in the hydrogen tank 40 is predicted to reach the threshold value SA is obtained from the following equation (6): T2 [days]=Q2 / q2 (6)

[0071] As a result of the above, the time when the remaining amount of hydrogen in the hydrogen tank 40 will be equal to or less than the threshold value SA can be predicted from the number of days T2.

[0072] Next, in step S5A, information indicating the time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA, as predicted in step S4A, is notified to the display device 50 by the communication device 21. The time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA may be provided to the user as, for example, information on the year, month, and day on a calendar displayed on the display device 50. Furthermore, if the time when the remaining amount of hydrogen in the hydrogen tank 40 will fall below threshold SA is stored in the memory of the controller 23, the stored time may be updated with new data. Thereafter, the operations from step S1 onwards are executed again at the next specified timing.

[0073] According to the present embodiment described above, by predicting the time when the remaining hydrogen amount in the hydrogen tank 40 will be below the threshold value SA based on the difference between the remaining hydrogen amount in the hydrogen tank 40 and the threshold value SA divided by the average daily amount of hydrogen used during period A excluding period B, the accuracy of the prediction can be improved compared to when no exclusion period is set in the calculation of hydrogen usage amount.

[0074] The method for predicting the remaining amount of hydrogen in the hydrogen tank 40, the device 20 for predicting the remaining amount of hydrogen in the hydrogen tank 40, and the power generation system 10 of this embodiment may be the same as those of the first embodiment except for the above-mentioned features.

[0075] (Second Example) The method for predicting the remaining amount of hydrogen in the hydrogen tank 40 in the second example of the first embodiment is the same as the method for predicting the remaining amount of hydrogen in the hydrogen tank 40 in the first embodiment, except that period A is one week or more weeks and period B is a number of weeks less than period A.

[0076] According to the present embodiment described above, by setting Period A and Period B to one week or multiple weeks, and to a number of weeks equal to or less than the first period, respectively, the prediction of when the remaining hydrogen level in the hydrogen tank 40 will fall below threshold SA is less affected by fluctuations in the amount of hydrogen used in daily activities. For example, the amount of hydrogen used during certain periods of the week (e.g., weekends) is generally less than during weekdays, but according to the present embodiment, by setting Period A and Period B as described above, the influence of daily fluctuations in the amount of hydrogen used that occur over the course of a week is reduced in the prediction of when the remaining hydrogen level in the hydrogen tank 40 will fall below threshold SA.

[0077] The method for predicting the remaining amount of hydrogen tank 40, the device 20 for predicting the remaining amount of hydrogen tank 40, and the power generation system 10 of this embodiment may be the same as those of the first embodiment or the first example of the first embodiment, except for the above-mentioned features.

[0078] (Variant) The method for predicting the remaining amount of hydrogen in the hydrogen tank 40 in a variant of the first embodiment is the same as the method for predicting the remaining amount of hydrogen in the hydrogen tank 40 in the first embodiment, except that when period A and period B are the same, the time when the remaining amount of hydrogen in the hydrogen tank 40 will be below threshold SA is not updated.

[0079] Here, "period A and period B are the same" means that the amount of hydrogen used in the hydrogen tank 40 is irregularly less than the normal amount of hydrogen used throughout the entire period A. Therefore, according to the modified example described above, when period A and period B are the same, the time when the remaining amount of hydrogen in the hydrogen tank 40 used by the fuel cell device 15 will be below threshold SA is not updated, thereby making it possible to more efficiently predict this time.

[0080] Other than the above-mentioned features, the method for predicting the remaining amount of hydrogen tank 40, the device 20 for predicting the remaining amount of hydrogen tank 40, and the power generation system 10 of this modified example may be similar to the first embodiment and any of the first to second examples of the first embodiment.

[0081] Second Embodiment Fig. 5 is a diagram showing an example of a power generation system according to a second embodiment. For convenience, the hydrogen tank 40 and the display device 50 shown in the first embodiment (Fig. 1) are not shown in Fig. 5. The internal configuration of the remaining amount prediction device 20 for the hydrogen tank 40 is the same as that of the first embodiment, and therefore a detailed description thereof will be omitted.

[0082] 5, the power generation system 10 of this embodiment comprises groups 15A to 15E obtained by dividing a fuel cell unit group corresponding to the fuel cell device 15 (see FIG. 1), a hydrogen tank remaining amount prediction device 20, and control devices 30A to 30E. In other words, the power generation system 10 comprises a fuel cell unit group made up of a plurality of fuel cell units.

[0083] Although not shown in the figure, each of these fuel cell units is composed of a fuel cell stack, an AC-to-AC converter for converting the 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.

[0084] 5, the fuel cell unit groups are divided into fuel cell units a1 to an belonging to group 15A, fuel cell units b1 to bn belonging to group 15B, fuel cell units c1 to cn belonging to group 15C, fuel cell units d1 to dn belonging to group 15D, and fuel cell units e1 to en belonging to group 15E. All of the fuel cell units belonging to one group are also simply referred to as "fuel cell units in the group."

[0085] However, the above configuration of the fuel cell unit group is merely an example and is not limited to this example. For example, the fuel cell unit group may be grouped by a single group of fuel cell units. Also, the number of fuel cell units in a group may be one.

[0086] Control devices 30A to 30E are provided for fuel cell units a1 to an in group 15A, fuel cell units b1 to bn in group 15B, fuel cell units c1 to cn in group 15C, fuel cell units d1 to dn in group 15D, and fuel cell units e1 to en in group 15E, respectively, and control the operation of each of the fuel cell units within the group.

[0087] For example, the control device 30A controls the output of each of the fuel cell units a1 to an belonging to the group 15A via a communication network so as to enable efficient operation (e.g., optimization of the life span) of these fuel cell units.

[0088] The control devices 30A to 30E may be any device that has a control function and includes a processing unit (not shown), a storage unit that stores a control program, and a communication device. The processing unit reads and executes the control program stored in the storage unit, thereby performing predetermined control in the control devices 30A to 30E. An example of the processing unit is a microprocessor. An example of the storage unit is a memory.

[0089] The above configuration of the power generation system 10 is an example, and is not limited to this example.

[0090] For example, the fuel cell units may not be provided with a control device, and the operation of the fuel cell units belonging to each group may be directly controlled by the control devices 30A to 30E.

[0091] Furthermore, the controller 23 (see FIG. 1) of the hydrogen tank 40 remaining amount prediction device 20 performs the operation of predicting when the remaining amount of hydrogen in the hydrogen tank 40 will fall below the threshold SA based on the amount of hydrogen in the hydrogen tank 40, but this is not limited to this. A control device other than the controller 23 (e.g., control devices 30A to 30E) may also perform this operation.

[0092] Furthermore, the remaining amount prediction device 20 for the hydrogen tank 40 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.

[0093] Other than the above-mentioned features, the method for predicting the remaining amount of hydrogen in a hydrogen tank 40, the device 20 for predicting the remaining amount of hydrogen in a hydrogen tank 40, and the power generation system 10 of this embodiment may be similar to any of the first embodiment, the first to second examples of the first embodiment, and the modified example of the first embodiment.

[0094] The first embodiment, the first example and the second example of the first embodiment, the modified example of the first embodiment, and the second embodiment 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.

[0095] One aspect of the present disclosure can be used in a hydrogen tank remaining capacity prediction method, a hydrogen tank remaining capacity prediction device, and a power generation system that can more accurately predict when the remaining hydrogen capacity in a hydrogen tank used in a fuel cell device will fall below a predetermined level.

[0096] 10: Power generation system 15: Fuel cell device 20: Remaining amount prediction device 21: Communication device 23: Controller 30A: Control device 30B: Control device 30C: Control device 30D: Control device 30E: Control device 40: Hydrogen tank 40A: Liquid hydrogen tank 40B: Hydrogen gas tank 40C: Hydrogen gas tank 41: Hydrogen gas tank 42: Liquid level sensor 43: Flow meter 44: Pressure gauge 50: Display device SA: Threshold value SB: Threshold value 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 method for predicting the remaining amount of hydrogen in a hydrogen tank used in a fuel cell device including at least one fuel cell unit, comprising the steps of: predicting a time when the remaining amount of hydrogen in the hydrogen tank will be below a first threshold value based on the amount of hydrogen in the hydrogen tank used in a first period spanning multiple days; and notifying a display device of said time, wherein when the amount of hydrogen in the hydrogen tank used in a second period spanning multiple days within the first period is below a second threshold value, the time is predicted based on the amount of hydrogen in the hydrogen tank used in a period of the first period excluding the second period.

2. The method for predicting remaining hydrogen tank capacity as set forth in claim 1, wherein when the first period and the second period are the same, the timing is not updated.

3. A method for predicting remaining hydrogen in a hydrogen tank as described in claim 1 or 2, which predicts the time based on a value obtained by dividing the difference between the remaining hydrogen amount in the hydrogen tank and a first threshold value by the average amount of hydrogen used per day during the first period excluding the second period.

4. A method for predicting remaining hydrogen tank capacity as described in any one of claims 1 to 3, wherein the first period is one week or more weeks, and the second period is a number of weeks less than or equal to the first period.

5. A hydrogen tank remaining amount prediction device used in a fuel cell device including at least one fuel cell unit, comprising: a controller that predicts when the remaining amount of hydrogen in the hydrogen tank will be below a first threshold amount based on the amount of hydrogen in the hydrogen tank used in a first period spanning multiple days; and a communication device controlled by the controller that notifies a display device of the time, wherein the controller predicts the time based on the amount of hydrogen in the hydrogen tank used in a period of multiple days within the first period excluding the second period when the amount of hydrogen in the hydrogen tank used in a second period spanning multiple days within the first period is below a second threshold amount.

6. A power generation system comprising: a fuel cell device including at least one fuel cell unit; and the hydrogen tank remaining amount prediction device according to claim 5.

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