Control method and control device for fuel cell device, and fuel cell system

Abstract

A method for controlling a fuel cell device according to the present disclosure includes: receiving a voltage measured when the fuel cell device generates power; whether the deterioration state of the fuel cell device is normal or not is determined on the basis of a comparison between the voltage and a first threshold value corresponding to the amount of operation of the fuel cell device when the voltage is measured, among first threshold values that decrease as the amount of operation of the fuel cell device increases.

Description

Technical Field

[0001] The present disclosure relates to a control method, a control device, and a fuel cell system for a fuel cell device. Background Art

[0002] Regarding the deterioration determination of a fuel cell device, various proposals have been made in the past. For example, Patent Document 1 discloses a solid oxide fuel cell characterized by including: a fuel cell module having a plurality of solid oxide fuel cell units (cells) and a reformer; a fuel supply unit that supplies fuel to the reformer; an oxidant gas supply unit that supplies an oxidant gas to the plurality of solid oxide fuel cell units; a water supply unit that supplies water to the reformer; and a control unit that changes the amount of fuel supplied from the fuel supply unit in correspondence with a requested power generation amount, the control unit including a deterioration determination unit that performs a deterioration determination of the fuel cell module, the deterioration determination unit performing the deterioration determination after a run in which a fixed amount of fuel, an oxidant gas, and water, which are obtained in advance, are supplied as fixed values from the fuel supply unit, the oxidant gas supply unit, and the water supply unit, respectively, until the fuel cell module reaches a stable operating state.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2010-238617 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] An object of the present disclosure is to provide, as an example, a control method, a control device, and a fuel cell system for a fuel cell device that can more appropriately monitor the deterioration state of the fuel cell device than in the past.

[0008] Technical Means for Solving the Problems

[0009] To solve the above problems, a control method for a fuel cell device according to an aspect of the present disclosure includes: receiving a voltage measured during power generation of the fuel cell device; and determining whether the deterioration state of the fuel cell device is normal based on a comparison of the voltage with a first threshold corresponding to an amount of operation of the fuel cell device at the time when the voltage is measured, the first threshold decreasing as the amount of operation of the fuel cell device increases.

[0010] In addition, a control device according to an aspect of the present disclosure includes: a receiver that receives a voltage measured during power generation of a fuel cell device; and a controller that determines whether the deterioration state of the fuel cell device is normal based on a comparison between the voltage and a first threshold value corresponding to the operation amount of the fuel cell device at the time when the voltage is measured, the first threshold value decreasing as the operation amount of the fuel cell device increases.

[0011] In addition, a fuel cell system according to an aspect of the present disclosure includes a fuel cell device and the above-described control device.

[0012] Advantageous Effects of the Invention

[0013] A control method, a control device, and a fuel cell system according to an aspect of the present disclosure have an effect of being able to more appropriately monitor the deterioration state of a fuel cell device as compared with the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a diagram showing an example of a fuel cell system according to an embodiment.

[0015] Figure 2 FIG. is a diagram showing Figure 1 an example of a control device.

[0016] Figure 3 FIG. is a diagram showing an example of a voltage stabilization timing at which the voltage stabilizes after a predetermined time has elapsed since the start of power generation of the fuel cell device.

[0017] Figure 4 FIG. is a flowchart showing an example of an operation (control method of a fuel cell device) of a control device in a fuel cell system according to an embodiment.

[0018] Figure 5 FIG. is a flowchart showing an example of a method for generating a first threshold value and a second threshold value, the first threshold value being used to determine whether the deterioration state of a fuel cell device is normal within a range where the voltage is lower than a predicted state of voltage decrease caused by deterioration of the fuel cell device, and the second threshold value being used to determine whether to continue power generation of the fuel cell device.

[0019] Figure 6 FIG. is a diagram showing an example of a first threshold value and a second threshold value, the first threshold value being used to determine whether the deterioration state of a fuel cell device is normal within a range where the voltage is lower than a predicted state of voltage decrease caused by deterioration of the fuel cell device, and the second threshold value being used to determine whether to continue power generation of the fuel cell device.

[0020] Figure 7It is a flowchart showing an example of the operation of a fuel cell device (control method of a fuel cell device) in a fuel cell system according to the first embodiment showing an embodiment. Detailed Embodiment

[0021] In Patent Document 1, deterioration determination of a fuel cell module is described, but only whether it has deteriorated is determined, and whether the deterioration state is normal when it has deteriorated is not determined.

[0022] Then, the control method of the fuel cell device according to the first aspect of the present disclosure includes: receiving the voltage measured during power generation of the fuel cell device; based on the comparison of the voltage with the first threshold corresponding to the operating amount of the fuel cell device at the time when the voltage is measured, which decreases as the operating amount of the fuel cell device increases, determining whether the deterioration state of the fuel cell device is normal.

[0023] According to the above, the control method of the fuel cell device according to the present aspect can more appropriately monitor the deterioration state of the fuel cell device compared with the prior art.

[0024] Specifically, in the control method of the fuel cell device according to the present aspect, compared with the case where the above-mentioned first threshold for determining whether the deterioration state of the fuel cell device is normal is not considered, it is possible to appropriately monitor whether the deterioration state of the fuel cell device is normal within the range where the voltage is lower than the predicted state of voltage decrease caused by the deterioration of the fuel cell device.

[0025] The control method of the fuel cell device according to the second aspect of the present disclosure may be that in the control method of the fuel cell device according to the first aspect, when the above-mentioned voltage is equal to or higher than the first threshold, the deterioration state of the fuel cell device is determined to be normal, when the voltage is less than the first threshold and equal to or higher than the second threshold smaller than the first threshold, the deterioration state of the fuel cell device is determined to be abnormal, and the fuel cell device continues to generate power, and when the voltage is less than the second threshold, the fuel cell device stops generating power.

[0026] According to the above, in the control method of the fuel cell device according to the present aspect, within the range where the voltage is lower than the predicted state of voltage decrease caused by the deterioration of the fuel cell device, when the voltage measured during power generation of the fuel cell device is less than the first threshold and equal to or higher than the second threshold, it is possible to know that the deterioration state of the fuel cell device is abnormal while the fuel cell device continues to generate power.

[0027] In addition, in the control method of the fuel cell device according to the present aspect, when the voltage measured during power generation of the fuel cell device is less than the second threshold, the fuel cell device stops generating power, whereby it is possible to perform repair or replacement of the fuel cell device in a timely manner.

[0028] The control method of the fuel cell device according to the third aspect of the present disclosure may be that in the control method of the fuel cell device according to the second aspect, the first threshold corresponding to the operating amount when the operating amount of the fuel cell device is determined to be the value of the life of the fuel cell device is equal to or greater than the second threshold.

[0029] As described above, the first threshold decreases as the operating amount of the fuel cell device increases. Therefore, in the control method of the fuel cell device according to this aspect, by making the magnitude relationship between the first threshold and the second threshold the above-mentioned relationship, it is possible to appropriately set the two so that the first threshold is not less than the second threshold throughout the period until the operating amount of the fuel cell device is determined to be the life of the fuel cell device.

[0030] The control method of the fuel cell device according to the fourth aspect of the present disclosure may be that in the control method of the fuel cell device according to the second or third aspect, the second threshold is constant regardless of the operating amount of the fuel cell device.

[0031] The control method of the fuel cell device according to the fifth aspect of the present disclosure may be that in the control method of the fuel cell device according to any one of the second to fourth aspects, when the voltage measured during power generation of the fuel cell device is less than the first threshold and not less than the second threshold, the fuel cell device is made to generate power under the same operating conditions as when the voltage is not less than the first threshold.

[0032] According to the above, in the control method of the fuel cell device according to this aspect, even when the voltage measured during power generation of the fuel cell device is less than the first threshold and not less than the second threshold, the fuel cell device is made to generate power while maintaining the operating conditions when the voltage is not less than the first threshold. Therefore, compared with the case where the fuel cell device generates power under operating conditions different from those when the voltage is not less than the first threshold, the output variation of the fuel cell device is suppressed.

[0033] The control method of the fuel cell device according to the sixth aspect of the present disclosure may be that in the control method of the fuel cell device according to any one of the second to fourth aspects, when the voltage measured during power generation of the fuel cell device is less than the first threshold and not less than the second threshold, the fuel cell device is made to generate power in such a manner that at least one of the fuel gas utilization rate and the oxidant gas utilization rate is equal to or higher than that when the voltage is not less than the first threshold.

[0034] According to the above, in the control method of the fuel cell device of the present technical solution, even when the voltage measured during the power generation of the fuel cell device is less than the first threshold and is equal to or greater than the second threshold, the fuel cell device is caused to generate power in such a way that at least one of the above gas utilization rates is equal to or higher than when the voltage is equal to or greater than the first threshold. Therefore, compared with the case where the fuel cell device generates power at a gas utilization rate lower than when the voltage is equal to or greater than the first threshold, the power generation efficiency of the fuel cell device is appropriately maintained or improved.

[0035] The control method of the fuel cell device according to the seventh aspect of the present disclosure may be that in the control method of the fuel cell device according to the first aspect, when the voltage measured during the power generation of the fuel cell device is equal to or greater than the first threshold, the deterioration state of the fuel cell device is determined to be normal, and when the voltage is less than the first threshold, the deterioration state of the fuel cell device is determined to be abnormal, and the fuel cell device is caused to continue generating power under the same operating conditions as when the voltage is equal to or greater than the first threshold.

[0036] According to the above, in the control method of the fuel cell device of the present technical solution, even when the voltage measured during the power generation of the fuel cell device is less than the first threshold, the fuel cell device is caused to generate power while maintaining the operating conditions when the voltage is equal to or greater than the first threshold. Therefore, compared with the case where the fuel cell device generates power under operating conditions different from those when the voltage is equal to or greater than the first threshold, fluctuations in the output of the fuel cell device can be suppressed.

[0037] The control method of the fuel cell device according to the eighth aspect of the present disclosure may be that in the control method of the fuel cell device according to the first aspect, when the voltage measured during the power generation of the fuel cell device is equal to or greater than the first threshold, the deterioration state of the fuel cell device is determined to be normal, and when the voltage is less than the first threshold, the deterioration state of the fuel cell device is determined to be abnormal, and the fuel cell device is caused to continue generating power in such a way that at least one of the fuel gas utilization rate and the oxidant gas utilization rate is equal to or higher than when the voltage is equal to or greater than the first threshold.

[0038] According to the above, in the control method of the fuel cell device of the present technical solution, even when the voltage measured during the power generation of the fuel cell device is less than the first threshold, the fuel cell device is caused to generate power in such a way that at least one of the above gas utilization rates is equal to or higher than when the voltage is equal to or greater than the first threshold. Therefore, compared with the case where the fuel cell device generates power at a gas utilization rate lower than when the voltage is equal to or greater than the first threshold, the power generation efficiency of the fuel cell device can be appropriately maintained or improved.

[0039] The control method of the fuel cell device according to the ninth aspect of the present disclosure may be to notify an external device of the determination result of whether the degradation state of the fuel cell device is normal in any one of the control methods of the fuel cell devices according to the first to fourth aspects.

[0040] The control method of the fuel cell device according to the tenth aspect of the present disclosure may be to correct the prediction of the replacement period of the fuel cell device and notify the external device of the corrected replacement period of the fuel cell device if the degradation state of the fuel cell device is determined to be abnormal in any one of the control methods of the fuel cell devices according to the first to fourth aspects.

[0041] Generally, the predicted value of the replacement period of the fuel cell is set to a value corresponding to the normal degradation of the fuel cell device. However, when the voltage measured during power generation becomes less than the first threshold and the degradation state of the fuel cell device is determined to be abnormal, this voltage drop is mostly an indication that the replacement period of the fuel cell device needs to be advanced.

[0042] Therefore, in the control method of the fuel cell device according to this aspect, when the degradation state of the fuel cell device is determined to be abnormal, by correcting the prediction of the replacement period of the fuel cell device based on the measured voltage less than the first threshold and notifying the external device of the corrected replacement period, compared with the case where the prediction of the replacement period is not corrected, appropriate information related to the replacement period of the fuel cell device can be obtained.

[0043] The control method of the fuel cell device according to the eleventh aspect of the present disclosure may be to correct the prediction of the maintenance period of the fuel cell device and notify the external device of the corrected maintenance period of the fuel cell device if the degradation state of the fuel cell device is determined to be abnormal in any one of the control methods of the fuel cell devices according to the first to fourth aspects.

[0044] Generally, the predicted value of the maintenance period of the fuel cell is set to a value corresponding to the normal degradation of the fuel cell device. However, when the voltage measured during power generation of the fuel cell device is less than the first threshold and the degradation state of the fuel cell device is determined to be abnormal, this voltage drop is mostly an indication that the maintenance period of the fuel cell device needs to be advanced.

[0045] Therefore, in the control method of the fuel cell device according to this aspect, when the degradation state of the fuel cell device is determined to be abnormal, by correcting the prediction of the maintenance period of the fuel cell device based on the measured voltage less than the first threshold and notifying the external device of the corrected replacement period, compared with the case where the prediction of the maintenance period is not corrected, appropriate information related to the maintenance period of the fuel cell device can be obtained.

[0046] The control device according to the 12th aspect of the present disclosure includes: a receiver that receives a voltage measured during power generation of a fuel cell device; and a controller that determines whether the deterioration state of the fuel cell device is normal based on a comparison between the voltage and a first threshold value corresponding to the operation amount of the fuel cell device at the time when the voltage is measured, the first threshold value decreasing as the operation amount of the fuel cell device increases.

[0047] According to this configuration, the control device of the present aspect can more appropriately monitor the deterioration state of the fuel cell device than in the past. In addition, the details of the effects achieved by the control device of the present aspect are the same as those achieved by the control method of the fuel cell device according to the 1st aspect, and thus the description thereof is omitted.

[0048] The fuel cell system according to the 13th aspect of the present disclosure includes a fuel cell device and the control device according to the 12th aspect.

[0049] According to this configuration, the fuel cell system of the present aspect can more appropriately monitor the deterioration state of the fuel cell device than in the past. In addition, the details of the effects achieved by the fuel cell system of the present aspect are the same as those achieved by the control method of the fuel cell device according to the 1st aspect, and thus the description thereof is omitted.

[0050] Hereinafter, with reference to the drawings, specific examples of the above aspects of the present disclosure will be described. The specific examples to be described below are all examples of the above aspects of the present disclosure. Therefore, with respect to the shapes, numerical values, constituent elements, arrangement positions of the constituent elements, connection methods, etc. shown below, as long as they are not described in the claims, they do not limit the scope of the claims.

[0051] In addition, with respect to the constituent elements not described in the independent claims representing the most general concept of the present disclosure among the constituent elements to be described below, they will be described as optional constituent elements. In addition, in the drawings, the description of the constituent elements denoted by the same reference numerals may sometimes be omitted. The drawings are diagrams schematically showing the respective constituent elements for ease of understanding, and therefore, the shapes, size ratios, etc. are not always accurately shown.

[0052] Moreover, in the operation of the device, the order of the steps may be changed as needed, and known steps may be added.

[0053] (Embodiment)

[0054] [Device Configuration]

[0055] Figure 1 is a diagram showing an example of the fuel cell system of the embodiment. Figure 2 is showing Figure 1 an example of the control device of

[0056] The fuel cell system 10 of this embodiment includes a fuel cell device 15 and a control device 20. Here, the fuel cell system 10 may be composed of a single power generation unit including a fuel cell, but as Figure 1 shown, it may also include a plurality of power generation units including fuel cells. In this example, the fuel cell system 10 includes a power generation unit group composed of power generation units a1~an, b1~bn, c1~cn, d1~dn, and e1~en. In this case, the fuel cell system 10 may also be, for example, a system that supplies large power to the power system. Thus, the configuration of the Figure 1 power generation unit group will be described in further detail below.

[0057] The power generation unit group is grouped by a plurality of power generation units a1~an, b1~bn, c1~cn, d1~dn, and e1~en. In addition, although not shown in the figure, these power generation units a1~an, b1~bn, c1~cn, d1~dn, and e1~en are each composed of a fuel cell stack, a power conditioner for converting the DC power generated by the fuel cell stack into AC power and outputting it to the power system, and a control device for controlling the operation of these devices.

[0058] In this example, the power generation unit group is grouped into power generation units a1~an belonging to group A, power generation units b1~bn belonging to group B, power generation units c1~cn belonging to group C, power generation units d1~dn belonging to group D, and power generation units e1~en belonging to group E. All the power generation units belonging to one group are also simply referred to as "the power generation units within the group". Hereinafter, for the sake of convenience of explanation, the power generation units a1~an, b1~bn, c1~cn, d1~dn, and e1~en may sometimes be abbreviated as "power generation units 15ij (i = a~e, j = 1~n)". In addition, in this example, each power generation unit corresponds to the fuel cell power generation device of the present disclosure, but each group may also correspond to the fuel cell power generation device of the present disclosure.

[0059] However, the above configuration of the power generation unit group is only an example and does not limit this example. For example, the power generation unit group may also be grouped by the power generation units within a single group.

[0060] Control devices 30A~30E are respectively provided for each of the power generation units a1~an of group A, the power generation units b1~bn of group B, the power generation units c1~cn of group C, the power generation units d1~dn of group D, and the power generation units e1~en of group E, and control the operation of each power generation unit within the group.

[0061] For example, the control device 30A controls the outputs of the power generation units a1 to an via a communication network so that the power generation units a1 to an belonging to group A can operate efficiently (e.g., optimization of lifespan).

[0062] The control devices 30A to 30E only need to have a control function, and include an arithmetic processing unit (not shown), a storage unit (not shown) that stores a control program, and a communicator (not shown). By the arithmetic processing unit reading and executing the control program stored in the storage unit, predetermined control is performed in the control devices 30A to 30E. As the arithmetic processing unit, a microprocessor is exemplified, for example. As the storage unit, a memory is exemplified, for example.

[0063] As Figure 2 shown, the control device 20 includes a receiver 21 and a controller 23. Here, the receiver 21 is a device that receives the voltage measured when the fuel cell device 15 generates power. For example, the receiver 21 can receive the above voltage transmitted by the fuel cell device 15 via a communication network at the timing when the voltage is stable when the fuel cell device 15 generates power at the rated output. For the "timing when the voltage is stable", for example, as Figure 3 shown, it is an appropriate timing within the time period (between time ta and time tb) when the voltage becomes stable after a predetermined time has elapsed since the fuel cell device 15 starts generating power. Thus, the voltage measured when the fuel cell device 15 generates power can be the average value of the voltage within this time period (between time ta and time tb).

[0064] The controller 23 determines whether the deterioration state of the fuel cell device 15 is normal based on a comparison between the voltage measured when the fuel cell device 15 generates power and the first threshold corresponding to the amount of operation of the fuel cell device 15 at the time when this voltage is measured, where the first threshold decreases as the amount of operation of the fuel cell device 15 increases. For the "amount of operation of the fuel cell device 15", for example, the cumulative power generation time or the cumulative number of power generation times can be cited, but it is not limited thereto. The first threshold is a reference voltage for determining whether the deterioration state of the fuel cell device 15 is normal within the range where the voltage is lower than the predicted state of voltage reduction due to the deterioration of the fuel cell device 15. The details of this first threshold are described in the first embodiment.

[0065] In this example, the above determination is performed for each of all the power generation units 15ij (i = a to e, j = 1 to n) of the fuel cell system 10 by the controller 23, but it is not limited thereto.

[0066] For example, although not shown in the figure, in the case where the fuel cell system 10 is composed of a single power generation unit, the above determination is performed for the single power generation unit by the controller 23.

[0067] In addition, the above determination may be performed for each of the power generation units 15ij (i = a to e, j = 1 to n) by a control device other than the controller 23 (for example, the control devices 30A to 30E).

[0068] Moreover, the above determination may be performed for each of the power generation units 15ij (i = a to e, j = 1 to n) by a control device other than the controller 23 and the control devices 30A to 30E (for example, control devices within each of the power generation units not shown).

[0069] It is sufficient for the controller 23 to have a control function, and it includes an arithmetic processing unit (not shown) and a storage unit (not shown) that stores a control program. By the arithmetic processing unit reading out and executing the control program stored in the storage unit, predetermined control is performed in the controller 23. As the arithmetic processing unit, for example, a microprocessor is exemplified. As the storage unit, for example, a memory is exemplified.

[0070] [Operation]

[0071] Figure 4 It is a flowchart showing an example of the operation of the control device (control method of the fuel cell device) in the fuel cell system of the embodiment. The following operations can be performed, for example, by the arithmetic processing unit of the controller 23 reading out the control program from the storage unit of the controller 23. However, it is not necessarily essential for the controller 23 to perform the following operations. Part of the operations may also be performed by the operator. In the following example, the case where the operations are controlled by the controller 23 is described.

[0072] First, when the operation of the control device 20 starts, in step S1, the voltage V measured during power generation of the fuel cell device 15 is received. Specifically, the voltage V measured by each of the power generation units 15ij (i = a to e, j = 1 to n) is received separately by the receiver 21 via the communication network.

[0073] Here, the timing for measuring the voltage V in each of the power generation units 15ij (i = a to e, j = 1 to n), for example, may be the voltage stabilization timing when each of the power generation units 15ij (i = a to e, j = 1 to n) generates power at the rated output.

[0074] Next, in step S2, based on the comparison between the voltage V in step S1 and the first threshold value that decreases as the operation amount of the fuel cell device 15 increases, and the first threshold value corresponding to the operation amount of the fuel cell device 15 when the voltage V is measured, it is determined whether the deterioration state of the fuel cell device 15 is normal. Specifically, for each of the power generation units 15ij (i = a to e, j = 1 to n), the voltage V in step S1 and the first threshold value are determined, and based on the comparison between the two, it is determined whether the deterioration state of each of the power generation units 15ij (i = a to e, j = 1 to n) is normal. In addition, when each of the groups A to E corresponds to the fuel cell power generation device of the present disclosure, the representative value of the operation amount of each of the groups A to E and the representative value of the voltage V are used to determine whether the deterioration state is normal. As the representative value of the operation amount of each of the groups A to E, for example, the average value or the median value of the operation amounts of the power generation units belonging to each of the groups A to E is used. In addition, as the representative value of the voltage V of each of the groups A to E, for example, the average value or the median value of the voltages of the power generation units belonging to each of the groups A to E is used.

[0075] In addition, it may be that for each of the power generation units 15ij (i = a to e, j = 1 to n), every time the cumulative power generation time, which is an example of the operation amount of the fuel cell device 15, increases by a certain time, or every time the cumulative power generation number, which is an example of the operation amount of the fuel cell device 15, increases by a certain number, the operations of step S1 and step S2 are repeated.

[0076] In addition, the determination result of whether the deterioration state of the fuel cell device 15 is normal can be notified to the external device 40 (refer to Figure 2 ). As the "external device 40", for example, it can be an information terminal, a display device. As the information terminal, an information terminal of a demand side that receives the power supply service generated by the fuel cell system 10 can be cited, and as the display device, a display device of a maintenance company etc. can be cited, but it is not limited thereto. Thereby, a demand side etc. that receives the power supply service generated by the fuel cell system 10 can easily know the deterioration state of the fuel cell device 15.

[0077] According to the present embodiment described above, compared with the prior art, the deterioration state of the fuel cell device 15 can be monitored more appropriately.

[0078] Specifically, according to the present embodiment, compared with the case where the above-mentioned first threshold value for determining whether the deterioration state of the fuel cell device 15 is normal is not considered, it is possible to appropriately monitor whether the deterioration state of the fuel cell device 15 is normal within the range where the voltage V is lower than the predicted state of the voltage drop caused by the deterioration of the fuel cell device 15.

[0079] (First Embodiment)

[0080] The control method of the fuel cell device 15 according to the first embodiment of the embodiment is the same as the control method of the fuel cell device 15 of the embodiment, except for the content described below.

[0081] In the control method of the fuel cell device 15 of this embodiment, when the voltage V measured during the power generation of the fuel cell device 15 is equal to or higher than the first threshold SH1, the deterioration state of the fuel cell device 15 is determined to be normal. When the voltage V is less than the first threshold SH1 and is equal to or higher than the second threshold SH2 smaller than the first threshold SH1, the deterioration state of the fuel cell device 15 is determined to be abnormal, and the fuel cell device 15 is made to continue power generation. When the voltage V is less than the second threshold SH2, the fuel cell device 15 is stopped from power generation. In other words, even if the abnormality of the deterioration state of the fuel cell device 15 continues, as long as the voltage V is equal to or higher than the second threshold SH2, the fuel cell continues to generate power.

[0082] [Regarding the first threshold SH1 and the second threshold SH2]

[0083] Figure 5 FIG. is a flowchart showing an example of a method for generating the first threshold and the second threshold. The first threshold is used to determine whether the deterioration state of the fuel cell device is normal within a range where the voltage is lower than a predicted state of voltage drop caused by the deterioration of the fuel cell device, and the second threshold is used to determine whether to make the fuel cell device continue power generation.

[0084] Figure 6 FIG. is a diagram showing an example of the first threshold and the second threshold. The first threshold is used to determine whether the deterioration state of the fuel cell device is normal within a range where the voltage is lower than a predicted state of voltage drop caused by the deterioration of the fuel cell device, and the second threshold is used to determine whether to make the fuel cell device continue power generation.

[0085] Here, Figure 6 the horizontal axis of takes the period from "zero" of the power generation time of the fuel cell device 15 to the cumulative power generation time (hereinafter, referred to as the reach-life determination time TE) determined to be the life of the fuel cell device 15.

[0086] Figure 6 the vertical axis of takes the voltage V of the fuel cell device 15 corresponding to the cumulative power generation time of the fuel cell device 15. This voltage V is measured in a timely manner as the cumulative power generation time of the fuel cell device 15 elapses. For example, it can be that every time the cumulative power generation time of the fuel cell device 15 increases by a predetermined power generation time, the measurement is performed when the fuel cell device 15 generates power. "When the fuel cell device 15 generates power" can be, for example, the voltage stabilization timing when the fuel cell device 15 generates power at the rated output.

[0087] As Figure 5As shown, in step S3, the initial voltage V0 during power generation of the fuel cell device 15 is measured. For example, it can be that after the fuel cell device 15 is manufactured, the initial voltage V0 is measured at the time when the voltage stabilizes when the fuel cell device 15 initially generates power at the rated output.

[0088] Here, as Figure 6 shown by the circular mark, it is generally known that as the cumulative power generation time of the fuel cell device 15 increases, the voltage V of the fuel cell device 15 gradually decreases. That is, Figure 6 the reference line R corresponds to a line drawn by linearly approximating the predicted state of the voltage drop caused by the deterioration of the fuel cell device 15. In addition, the cumulative power generation time of the fuel cell device 15 is the voltage V1 ([[]] Figure 6 the voltage of the black dot mark) at the time when the life determination time TE is reached, which is a known determined value.

[0089] Next, as Figure 5 shown, in step S4, the initial voltage V0 in step S3 is used to generate the first threshold SH1. In addition, the voltage V1 is used to generate the second threshold SH2.

[0090] As Figure 6 shown, the first threshold SH1 is determined by a straight line drawn in a manner that decreases as the cumulative power generation time of the fuel cell device 15 increases within the range where the voltage V is lower than the predicted state of the voltage drop caused by the deterioration of the fuel cell device 15 (refer to [[[]] Figure 6 the reference line R).

[0091] In this example, the first threshold SH1 is determined by a straight line passing through the position P0(0, V0 - Δα) when the voltage at the time of "zero" power generation time of the fuel cell device 15 is lower than the initial voltage V0 by a predetermined value Δα, and the position PE(TE, V1) when the voltage at the time when the cumulative power generation time of the fuel cell device 15 reaches the life determination time TE is the voltage V1. The predetermined value Δα can be set to an appropriate voltage between the initial voltage V0 and the voltage V1. The predetermined value Δα can also be, for example, around (V0 - V1) / 2.

[0092] In addition, as Figure 6 shown, the second threshold SH2 is less than the first threshold SH1 and is constant, independent of the operation amount (here, the cumulative power generation time) of the fuel cell device 15.

[0093] In this example, the second threshold SH2 is determined by a straight line passing through the position P1(0, V1) where the voltage is V1 when the power generation time of the fuel cell device 15 is "zero", and the position PE(TE, V1) where the voltage is V1 when the cumulative power generation time of the fuel cell device 15 reaches the lifetime determination time TE. In this case, the second threshold SH2 is "voltage V1".

[0094] Furthermore, the first threshold SH1 corresponding to the operation amount when the operation amount of the fuel cell device 15 is determined to be the value of the lifetime of the fuel cell device 15 (here, reaching the lifetime determination time TE) can be equal to the second threshold SH2 or larger than the second threshold SH2. Thus, the first threshold SH1 linearly decreases as the operation amount of the fuel cell device 15 increases. Therefore, by setting the magnitude relationship between the first threshold SH1 and the second threshold SH2 to the above relationship, it is possible to appropriately set both of them so that the first threshold SH1 is not less than the second threshold SH2 throughout the entire period until the operation amount of the fuel cell device 15 is determined to be the lifetime of the fuel cell device 15.

[0095] [Operation]

[0096] Figure 7 It is a flowchart showing an example of the operation (control method of the fuel cell device) of the fuel cell device in the fuel cell system of the first embodiment of the embodiment. The following operations can be performed, for example, by the arithmetic processing unit of the controller 23 reading a control program from the storage unit of the controller 23. However, it is not necessary for the controller 23 to perform the following operations. The operator can also perform a part of the operations. In the following example, the case where the operations are controlled by the controller 23 will be described.

[0097] First, when the operation of the control device 20 starts, in step S11, the voltage V measured during the power generation of the fuel cell device 15 is received. Specifically, the voltage V measured by each of the power generation units 15ij (i = a to e, j = 1 to n) is received via the communication network by the receiver 21.

[0098] Here, the timing for measuring the voltage V in each of the power generation units 15ij (i = a to e, j = 1 to n) can be, for example, the voltage stabilization timing when each of the power generation units 15ij (i = a to e, j = 1 to n) generates power at the rated output.

[0099] In addition, for a part of the power generation units among the power generation units 15ij (i = a to e, j = 1 to n), for example Figure 6 as indicated by the triangular mark, there is a situation where as the cumulative power generation time of this power generation unit increases, the voltage V in step S11 deviates from the predicted state of the voltage drop due to the deterioration of this power generation unit (refer toFigure 6 than the way of the reference line R) Figure 6 where the voltage is lower than that indicated by the circular mark.

[0100] Next, in step S21, it is determined whether the voltage V in step S11 is equal to or higher than the first threshold value SH1 corresponding to the cumulative power generation time of the fuel cell device 15 when the voltage V is measured.

[0101] Here, when the voltage V in step S11 is equal to or higher than the first threshold value SH1 (when "Yes" in step S21), in step S22, the deterioration state of the fuel cell device 15 is determined to be normal. For example, as Figure 6 shown, when the voltage V in step S11 is the voltage corresponding to the dot area, the deterioration state of the fuel cell device 15 is determined to be normal.

[0102] Conversely, when the voltage V in step S11 is less than the first threshold value SH1 (when "No" in step S21), the process proceeds to the next determination step, and in step S23, it is determined whether the voltage V in step S11 is equal to or higher than the second threshold value SH2.

[0103] Here, when the voltage V in step S11 is equal to or higher than the second threshold value SH2 (when "Yes" in step S23), in step S24, the deterioration state of the fuel cell device 15 is determined to be abnormal, and the fuel cell device 15 continues to generate power. For example, as Figure 6 shown, when the voltage V in step S11 is the voltage corresponding to the slant area between the first threshold value SH1 and the second threshold value SH2, the deterioration state of the fuel cell device 15 is determined to be abnormal.

[0104] Conversely, when the voltage V in step S11 is less than the second threshold value SH2 (when "No" in step S23), in step S25, the fuel cell device 15 stops generating power. For example, as Figure 6 shown, when the voltage V in step S11 is the voltage corresponding to the shaded range less than the second threshold value SH2, the fuel cell device 15 stops generating power. Here, when each of the groups A to E corresponds to the fuel cell power generation device, for the group where the voltage V is less than the second threshold value SH2, all the power generation units belonging to the group stop generating power.

[0105] As described above, according to the present embodiment, within the range where the voltage V is lower than the predicted state of the voltage drop caused by the deterioration of the fuel cell device 15 (refer to Figure 6 the reference line R), when the voltage V measured during the power generation of the fuel cell device 15 is less than the first threshold value SH1 and equal to or higher than the second threshold value SH2, it is possible to know that the deterioration state of the fuel cell device 15 is abnormal while the fuel cell device 15 continues to generate power.

[0106] In addition, according to this embodiment, when the voltage V measured during power generation of the fuel cell device 15 is less than the second threshold value SH2, the power generation of the fuel cell device 15 is stopped. Thus, repair or replacement of the fuel cell device 15 can be carried out in a timely manner.

[0107] The control method, control device 20, and fuel cell system 10 of the fuel cell device 15 of this embodiment may be the same as those of the embodiment except for the above features.

[0108] (Second Embodiment)

[0109] Regarding the control method of the fuel cell device 15 of the second embodiment of the embodiment, it is the same as the control method of the fuel cell device 15 of the embodiment except for the content to be described below.

[0110] In the control method of the fuel cell device 15 of this embodiment, when the voltage V measured during power generation of the fuel cell device 15 is less than the first threshold value SH1 and is equal to or more than the second threshold value SH2, the fuel cell device 15 is made to generate power under the same operating conditions as when the voltage V is equal to or more than the first threshold value SH1.

[0111] According to the above, in the control method of the fuel cell device 15 of this embodiment, even when the voltage V measured during power generation of the fuel cell device 15 is less than the first threshold value SH1 and is equal to or more than the second threshold value SH2, the fuel cell device 15 is made to generate power while maintaining the state of the operating conditions when the voltage V is equal to or more than the first threshold value SH1. Therefore, compared with the case where the fuel cell device 15 is made to generate power under operating conditions different from those when the voltage is equal to or more than the first threshold value, the output variation of the fuel cell device 15 is suppressed.

[0112] Regarding the control method, control device 20, and fuel cell system 10 of the fuel cell device 15 of this embodiment, they may be the same as those of the embodiment or the first embodiment of the embodiment except for the above features.

[0113] (Third Embodiment)

[0114] Regarding the control method of the fuel cell device 15 of the third embodiment of the embodiment, it is the same as the control method of the fuel cell device 15 of the embodiment except for the content described below.

[0115] In the control method of the fuel cell device 15 according to this embodiment, when the voltage V measured during power generation of the fuel cell device 15 is less than the first threshold value SH1 and is equal to or higher than the second threshold value SH2, the fuel cell device 15 is caused to generate power in such a manner that at least one of the fuel gas utilization rate and the oxidant gas utilization rate is equal to or higher than when the voltage V is equal to or higher than the first threshold value SH1.

[0116] According to the above, in the control method of the fuel cell device 15 according to this embodiment, even when the voltage V measured during power generation of the fuel cell device 15 is less than the first threshold value SH1 and is equal to or higher than the second threshold value SH2, the fuel cell device 15 is caused to generate power in such a manner that at least one of the above gas utilization rates is equal to or higher than when the voltage V is equal to or higher than the first threshold value SH1. Therefore, compared with the case where the fuel cell device 15 generates power with a gas utilization rate lower than when the voltage is equal to or higher than the first threshold value SH1, the power generation efficiency of the fuel cell device 15 is appropriately maintained or improved.

[0117] For the control method, control device 20, and fuel cell system 10 of the fuel cell device 15 according to this embodiment, except for the above features, they may be the same as those of the embodiment or the first embodiment of the embodiment.

[0118] (Fourth Embodiment)

[0119] For the control method of the fuel cell device 15 according to the fourth embodiment of the embodiment, except for the content described below, it is the same as the control method of the fuel cell device 15 of the embodiment.

[0120] In the control method of the fuel cell device 15 according to this embodiment, when the voltage measured during power generation of the fuel cell device 15 is equal to or higher than the first threshold value SH1, the deterioration state of the fuel cell device 15 is determined to be normal. When the voltage V is less than the first threshold value SH1, the deterioration state of the fuel cell device 15 is determined to be abnormal, and the fuel cell device 15 is caused to continue generating power under the same operating conditions as when the voltage V is equal to or higher than the first threshold value.

[0121] According to the above, in the control method of the fuel cell device 15 according to this embodiment, even when the voltage V measured during power generation of the fuel cell device 15 is less than the first threshold value SH1, the fuel cell device 15 is caused to generate power while maintaining the operating conditions when the voltage V is equal to or higher than the first threshold value SH1. Therefore, it can be known that compared with the case where the fuel cell device 15 generates power under operating conditions different from those when the voltage is equal to or higher than the first threshold value, the output variation of the fuel cell device 15 is suppressed.

[0122] For the control method, control device 20, and fuel cell system 10 of the fuel cell device 15 in this embodiment, except for the above features, they may be the same as those in the embodiment or the first embodiment of the embodiment.

[0123] (Fifth Embodiment)

[0124] For the control method of the fuel cell device 15 in the fifth embodiment of the embodiment, except for the content described below, it is the same as the control method of the fuel cell device 15 in the embodiment.

[0125] In the control method of the fuel cell device 15 in this embodiment, when the voltage V measured during power generation of the fuel cell device 15 is equal to or higher than the first threshold SH1, the deterioration state of the fuel cell device 15 is determined to be normal. When the voltage V is less than the first threshold SH1, the deterioration state of the fuel cell device 15 is determined to be abnormal, and the fuel cell device 15 continues to generate power in such a way that at least one of the fuel gas utilization rate and the oxidant gas utilization rate is equal to or higher than that when the voltage V is equal to or higher than the first threshold SH1.

[0126] According to the above, in the control method of the fuel cell device 15 in this embodiment, even when the voltage V measured during power generation of the fuel cell device 15 is less than the first threshold SH1, the fuel cell device 15 generates power in such a way that at least one of the above gas utilization rates is equal to or higher than that when the voltage V is equal to or higher than the first threshold SH1. Therefore, compared with the case where the fuel cell device 15 generates power at a gas utilization rate lower than that when the voltage is equal to or higher than the first threshold SH1, the power generation efficiency of the fuel cell device 15 can be appropriately maintained or improved.

[0127] For the control method, control device 20, and fuel cell system 10 of the fuel cell device 15 in this embodiment, except for the above features, they may be the same as those in the embodiment or the first embodiment of the embodiment.

[0128] (First Variation)

[0129] In the control method of the fuel cell device 15 in the first variation of the embodiment, if the deterioration state of the fuel cell device 15 is determined to be abnormal, the prediction of the replacement period of the fuel cell device 15 is corrected, and the corrected replacement period of the fuel cell device 15 is notified to the external device 40. Except for this, it is the same as the control method of the fuel cell device 15 in the embodiment.

[0130] Generally, the predicted value of the replacement period of the fuel cell is set to a value corresponding to the normal deterioration of the fuel cell device 15. However, when the measured voltage V during power generation of the fuel cell device 15 is less than the first threshold SH1 and the deterioration state of the fuel cell device 15 is determined to be abnormal, this voltage drop is mostly an omen that the replacement period of the fuel cell device 15 needs to be advanced.

[0131] Therefore, in the control method of the fuel cell device 15 of this modified example, when the deterioration state of the fuel cell device 15 is determined to be abnormal, the prediction of the replacement period of the fuel cell device 15 is corrected based on the measured voltage less than the first threshold SH1, and it is notified to the external device 40. Thus, compared with the case where the prediction of the replacement period is not corrected, appropriate information related to the replacement period of the fuel cell device 15 can be obtained.

[0132] For the control method, control device 20, and fuel cell system 10 of the fuel cell device 15 of this modified example, except for the above features, they can be the same as any one of the embodiments and the first to fifth embodiments of the embodiments.

[0133] (Second Modified Example)

[0134] In the control method of the fuel cell device 15 in the second modified example of the embodiment, if the deterioration state of the fuel cell device 15 is determined to be abnormal, the prediction of the maintenance period of the fuel cell device 15 is corrected, and the corrected maintenance period of the fuel cell device 15 is notified to the external device 40. Other than this, it is the same as the control method of the fuel cell device 15 in the embodiment.

[0135] Generally, the predicted value of the maintenance period of the fuel cell is set to a value corresponding to the normal deterioration of the fuel cell device 15. However, when the measured voltage V during power generation of the fuel cell device 15 is less than the first threshold SH1 and the deterioration state of the fuel cell device 15 is determined to be abnormal, this voltage drop is mostly an omen that the maintenance period of the fuel cell device 15 needs to be advanced.

[0136] Therefore, in the control method of the fuel cell device 15 of this modified example, when the deterioration state of the fuel cell device 15 is determined to be abnormal, the prediction of the maintenance period of the fuel cell device 15 is corrected based on the measured voltage less than the first threshold SH1, and it is notified to the external device 40. Thus, compared with the case where the prediction of the maintenance period is not corrected, appropriate information related to the maintenance period of the fuel cell device 15 can be obtained.

[0137] For the control method, control device 20, and fuel cell system 10 of the fuel cell device 15 of this modification example, other than the above features, they may be the same as any one of the embodiments and the first to fifth embodiments of the embodiments.

[0138] For the embodiments, the first to fifth embodiments of the embodiments, and the first to second modification examples of the embodiments, as long as they are not mutually exclusive, they can be combined with each other. From the above description, for those skilled in the art, many improvements and other embodiments of the present disclosure are clear. Therefore, the above description should be construed only as an exemplification and is provided for the purpose of teaching those skilled in the art the best technical solution for implementing the present disclosure. As long as the spirit of the present disclosure is not departed from, the details of its structure and / or function can be substantially changed.

[0139] Industrial Applicability

[0140] One technical solution of the present disclosure can be applied to a control method, control device, and fuel cell system of a fuel cell device that can more appropriately monitor the deterioration state of the fuel cell device compared to the prior art.

[0141] Reference Numeral Explanation

[0142] 10: Fuel cell system

[0143] 15: Fuel cell device

[0144] 15ij: Power generation unit

[0145] 20: Control device

[0146] 21: Receiver

[0147] 23: Controller

[0148] 30A: Control device

[0149] 30B: Control device

[0150] 30C: Control device

[0151] 30D: Control device

[0152] 30E: Control device

[0153] 40: External device

[0154] SH1: First threshold

[0155] SH2: Second threshold

[0156] a1 to an: Power generation unit

[0157] b1 to bn: Power generation unit

[0158] c1 to cn: power generation units

[0159] d1 to dn: power generation units

[0160] e1 to en: power generation units.

Claims

1. A control method for a fuel cell device, receiving the voltage measured during power generation of the fuel cell device; judging whether the degradation state of the fuel cell device is normal based on a comparison between the voltage and a first threshold value corresponding to the operating amount of the fuel cell device at the time when the voltage is measured, wherein the first threshold value decreases as the operating amount of the fuel cell device increases.

2. A control method for a fuel cell device, when the voltage is greater than or equal to the first threshold value, judging that the degradation state of the fuel cell device is normal; when the voltage is less than the first threshold value and greater than or equal to a second threshold value smaller than the first threshold value, judging that the degradation state of the fuel cell device is abnormal and continuing power generation of the fuel cell device; when the voltage is less than the second threshold value, stopping power generation of the fuel cell device.

3. The control method for a fuel cell device according to claim 2, the first threshold value corresponding to the operating amount when the operating amount of the fuel cell device is judged to be the value of the life of the fuel cell device is equal to or greater than the second threshold value.

4. The control method for a fuel cell device according to claim 2 or 3, the second threshold value is constant and independent of the operating amount of the fuel cell device.

5. The control method for a fuel cell power generation device according to any one of claims 2 to 4, when the voltage is less than the first threshold value and greater than or equal to the second threshold value, making the fuel cell device generate power under the same operating conditions as when the voltage is greater than or equal to the first threshold value.

6. The control method for a fuel cell power generation device according to any one of claims 2 to 4, when the voltage is less than the first threshold value and greater than or equal to the second threshold value, making the fuel cell device generate power in such a way that at least one of the fuel gas utilization rate and the oxidant gas utilization rate is equal to or higher than that when the voltage is greater than or equal to the first threshold value.

7. The control method for a fuel cell device according to claim 1, when the voltage is greater than or equal to the first threshold value, judging that the degradation state of the fuel cell device is normal; when the voltage is less than the first threshold value, judging that the degradation state of the fuel cell device is abnormal and continuing power generation of the fuel cell device under the same operating conditions as when the voltage is greater than or equal to the first threshold value.

8. The control method for a fuel cell device according to claim 1, when the voltage is greater than or equal to the first threshold value, judging that the degradation state of the fuel cell device is normal; when the voltage is less than the first threshold value, judging that the degradation state of the fuel cell device is abnormal and continuing power generation of the fuel cell device in such a way that at least one of the fuel gas utilization rate and the oxidant gas utilization rate is equal to or higher than that when the voltage is greater than or equal to the first threshold value.

9. The control method for a fuel cell device according to any one of claims 1 to 4, Notify an external device of the determination result as to whether the degradation state of the fuel cell device is normal.

10. The control method of a fuel cell device according to any one of claims 1 to 4, if the degradation state of the fuel cell device is determined to be abnormal, correct the prediction of the replacement period of the fuel cell device, and notify the external device of the corrected replacement period of the fuel cell device.

11. The control method of a fuel cell device according to any one of claims 1 to 4, if the degradation state of the fuel cell device is determined to be abnormal, correct the prediction of the maintenance period of the fuel cell device, and notify the external device of the corrected maintenance period of the fuel cell device.

12. A control device includes: a receiver that receives a voltage measured during power generation of a fuel cell device; and a controller that determines whether the degradation state of the fuel cell device is normal based on a comparison of the voltage with a first threshold value that decreases as the operation amount of the fuel cell device increases and corresponds to the operation amount of the fuel cell device when the voltage is measured.

13. A fuel cell system includes: a fuel cell device; and the control device according to claim 12.

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