Control system for fuel cell

Abstract

To provide a control system for a fuel cell, the control system enabling suppression of deterioration of power generation performance regardless of power generation stop frequency and an ambient environment.MEANS FOR SOLVING THE PROBLEM: According to an embodiment, a control system for a fuel cell is a control system for a fuel cell for controlling a fuel cell provided with a fuel cell stack for generating power by chemical reaction. The control system for a fuel cell according to the embodiment comprises a power demand acquisition part for acquiring a power demand amount of the fuel cell at a supply destination of the fuel cell, a learning calculation part for learning and holding a time series pattern of the power demand amount on the basis of an acquisition result of the power demand acquisition part, a storage part for storing performance deterioration amount information indicating a performance deterioration amount of the fuel cell stack, and an operation determination part for determining whether an operation stop of the fuel cell is possible or not on the basis of the time series pattern of the power demand amount and the performance deterioration amount information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments relate to a fuel cell control system. [Background technology]

[0002] A fuel cell (system) is equipped with a fuel cell stack, which is the smallest unit of power generation. It is known that the amount of degradation in the power generation performance of a fuel cell stack is determined by the power generation time and the number of starts and stops. In other words, fuel cells have the property that their power generation performance degrades not only with the power generation itself but also by stopping and restarting power generation. Therefore, the amount of degradation in power generation performance will differ depending on the time between when power generation is no longer needed and when it is needed again, depending on whether the fuel cell continues to generate power without stopping it when power generation is no longer needed or when power generation is stopped and then restarted when it is needed again.

[0003] Therefore, if power generation is stopped when the time between when the fuel cell no longer needs to generate power and when it will again be needed is short, there is a problem in that power generation performance will be lower than if power generation had continued without being stopped.

[0004] On the other hand, fuel cells sometimes use water as their cooling water, and if such fuel cells are placed in a low-temperature environment below freezing while power generation is stopped, the cooling water freezes, causing the fuel cells to be unable to start. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-231108 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, conventional fuel cell control systems have the problem that their power generation performance may be significantly reduced or they may even be unable to start depending on the frequency of power generation stoppages and the surrounding environment. The fuel cell control system of the embodiment has been made to solve these problems, and aims to provide a fuel cell control system that can suppress the reduction in power generation performance regardless of the frequency of power generation stoppages and the surrounding environment. [Means for solving the problem]

[0007] The fuel cell control system of the embodiment is a fuel cell control system for controlling a fuel cell including a fuel cell stack that generates electric power through a chemical reaction, and includes a power demand acquisition unit that acquires the amount of electric power demand of the fuel cell at a supply destination of the fuel cell, a learning calculation unit that learns and stores a time series pattern of the electric power demand based on the results acquired by the power demand acquisition unit, a memory unit that stores performance degradation amount information that indicates the amount of performance degradation of the fuel cell stack, and an operation determination unit that determines whether to stop operation of the fuel cell based on the time series pattern of the electric power demand and the performance degradation amount information. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the functional configuration of a fuel cell control system according to first to fifth embodiments. [Figure 2] 4 is a flowchart showing an example of the operation of the fuel cell control system according to the first embodiment. [Figure 3] 10 is a flowchart showing an example of the operation of the fuel cell control system according to the second embodiment. [Figure 4] 10 is a flowchart showing an example of the operation of a fuel cell control system according to a third embodiment. [Figure 5] 10 is a flowchart showing an example of the operation of a fuel cell control system according to a third embodiment. [Figure 6] 10 is a flowchart showing an example of the operation of a fuel cell control system according to a fourth embodiment. [Figure 7]10 is a flowchart showing an example of the operation of a fuel cell control system according to a fifth embodiment. [Figure 8] FIG. 10 is a block diagram showing the functional configuration of a fuel cell control system according to a sixth embodiment. [Figure 9] 10 is a flowchart showing an example of the operation of a fuel cell control system according to a sixth embodiment. [Figure 10] FIG. 13 is a block diagram showing the functional configuration of a fuel cell control system according to a seventh embodiment. [Figure 11] 13 is a flowchart showing an example of the operation of the fuel cell control system according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First to fifth embodiments) First to fifth embodiments of the present invention will be described below with reference to the drawings. In the following description, common components are designated by common reference numerals, and duplicated explanations will be omitted. FIG. 1 is a block diagram showing the functional configuration of a fuel cell control system according to the first to fifth embodiments. FIG. 2 is a flowchart showing an example of the operation of the fuel cell control system according to the first embodiment. The fuel cell control system of the embodiments acquires and learns from operating records and weather forecasts, and performs optimal operation so that the fuel cell and battery are operated in a manner that is most beneficial to the user.

[0010] As shown in Fig. 1, the fuel cell system 1 of this embodiment includes a fuel cell 2 and a fuel cell control system 3. The fuel cell 2 includes a fuel cell stack 100 that uses hydrogen as fuel, for example, a power generation control unit 110 that controls the power generation of the fuel cell stack, an operation switching unit 120 that switches between grid-connected operation and stand-alone operation, a generated power measurement unit 122 that measures the power generated by the fuel cell stack 100, and a performance degradation measurement unit 126 that measures the amount of performance degradation of the fuel cell stack 100. The fuel cell control system 3 includes a cell information acquisition unit 10, a power demand acquisition unit 12 that acquires the power demand of the fuel cell 2 (fuel cell stack 100), a learning calculation unit 20, a learning database (DB) 22, a memory unit 30, and an operation determination unit 40. The fuel cell control system 3 can be realized by a so-called computer device equipped with a calculation unit, a memory unit, etc.

[0011] The fuel cell stack 100 is an element that generates output power for the fuel cell 2 by chemically reacting, for example, hydrogen and oxygen. The fuel cell stack 100 generally has a structure in which fuel cell units are stacked. The amount of degradation in the power generation performance of the fuel cell stack can be determined from the power generation time and the number of starts and stops (restarts).

[0012] The power generation control unit 110 is a functional element that can control the start and stop of the fuel cell stack 100. The power generation control unit 110 can control the power generation of the fuel cell stack 100 based on a command signal from the fuel cell control system 3. The power generation control unit 110 may control the amount of power generation of the fuel cell stack 100 based on the amount of power demand acquired by the power demand acquisition unit 12.

[0013] The operation switching unit 120 is a functional element that can set the operation of the fuel cell 2 to either grid-connected operation or independent operation. Grid-connected operation is an operating state in which the fuel cell 2 is connected to a power grid and operates in a grid-connected manner. Independent operation is an operating state in which the fuel cell 2 is disconnected from other power supply sources and can operate independently. In other words, the fuel cell 2 can be configured to be able to operate in a grid-connected manner with a power grid. The power generation control unit 110 and the operation switching unit 120 can be realized by a so-called computer device.

[0014] The generated power measurement unit 122 is a functional element that measures the generated power of the fuel cell stack 100. The generated power measured by the generated power measurement unit 122 can be used as a parameter for measuring the amount of performance degradation of the fuel cell stack 100.

[0015] The performance degradation amount measurement unit 126 is a functional element that can measure the amount of degradation (performance degradation amount information) of the power generation performance of the fuel cell stack 100. The performance degradation amount information is, for example, information related to the generated voltage of the fuel cell stack 100, and examples thereof include the amount of degradation in the power generation performance of the fuel cell stack 100 when the operation of the fuel cell 2 is stopped, and the amount of degradation in the power generation performance of the fuel cell stack 100 per unit time when the fuel cell 2 is operating. The performance degradation amount information may also include the output current of the fuel cell stack 100 and the amount of fuel consumed by the fuel cell stack 100.

[0016] Based on the measurement results of the generated power measurement unit 122, the performance degradation amount measurement unit 126 can measure the amount of degradation in the power generation performance of the fuel cell stack 100 when the operation of the fuel cell 2 is stopped, and the amount of degradation in the power generation performance of the fuel cell stack 100 per unit time when the fuel cell 2 is operating, and output the results as performance degradation amount information.

[0017] The generated power measurement unit 122 and the performance degradation measurement unit 126 can output the measurement results to the fuel cell control system 3.

[0018] The battery information acquisition unit 10 is a functional element capable of receiving voltage values, performance degradation amounts, etc. from the fuel cell 2. The battery information acquisition unit 10 is configured to be able to acquire in real time from the fuel cell 2 the power generation power of the fuel cell stack 100 measured by the power generation power measurement unit 122, the performance degradation amount of the fuel cell stack 100 measured by the performance degradation amount measurement unit 126, etc. The battery information acquisition unit 10 can store the acquired various pieces of information in the memory unit 30.

[0019] The power demand acquisition unit 12 is a functional element that acquires the amount of power demand of the power supply destination. The power demand acquisition unit 12 can acquire, for example, supplied power information from the power supply destination of the fuel cell 2. The power demand of the fuel cell stack 100 acquired by the power demand acquisition unit 12 can be used as a control parameter in the power generation control unit 110. In other words, the power generation control unit 110 can control the amount of power generated by the fuel cell stack 100 based on the demand acquired by the power demand acquisition unit 12 or by following the demand.

[0020] The learning calculation unit 20 is a functional element that learns and calculates the time series pattern of power demand at the power supply destination of the fuel cell 2. The learning calculation unit 20 accumulates the supply power of the fuel cell stack 100 measured by the power demand acquisition unit 12 in real time, and generates time series change data (time series pattern) of the power demand. The time series pattern of the power demand can be realized as a function that can predict the time series change of the power demand over a predetermined period (for example, one day or one week). In other words, when a time is given, the time series pattern of the power demand can provide the power demand of the fuel cell 2 at that time.

[0021] The learning database (DB) 22 is a database that stores the time series patterns of the amount of power demand generated by the learning calculation unit 20.

[0022] The memory unit 30 is a storage medium capable of storing various types of information about the fuel cell stack 100. The memory unit 30 can be realized by a non-volatile memory or the like. The memory unit 30 stores information about the voltage generated by the fuel cell stack 100, the amount of performance degradation, and the like. The contents of the memory unit 30 may be stored in advance or may be stored afterwards.

[0023] The operation determination unit 40 is a functional element that determines whether to stop or continue operation of the fuel cell 2. For example, when the power required for the fuel cell 2 to generate falls below the minimum power output of the fuel cell 2, requiring the fuel cell 2 to stop operation, the operation determination unit 40 can obtain the period for which the operation of the fuel cell 2 is required to be stopped based on the time series pattern of the power demand of the fuel cell 2 stored in the learning database 22. That is, the operation determination unit 40 obtains the period for which the power demand of the fuel cell 2 continues to be less than the minimum power output of the fuel cell 2 (the operation stop time). Here, the minimum power output of the fuel cell 2 refers to the minimum output power that can be generated by the fuel cell 2 (fuel cell stack 100). Based on the operation stop time, the operation determination unit 40 then compares the amount of decrease in the power generation performance of the fuel cell stack 100 when the operation of the fuel cell 2 is stopped during the operation stop time with the amount of decrease in the power generation performance of the fuel cell stack 100 when the operation of the fuel cell 2 is continued during the operation stop time. Based on the comparison result, the operation determination unit 40 determines whether the operation of the fuel cell 2 should be continued or stopped in order to prevent a decrease in the power generation performance of the fuel cell stack 100.

[0024] Furthermore, the fuel cell control system 3 of this embodiment has an input unit 50, an output unit 52, a performance degradation amount updating unit 60, an operation control unit 70, an environment acquisition unit 80, and a power outage determination unit 90.

[0025] The input unit 50 (data input unit) is an input interface that can acquire information from a user, etc. Examples of the input unit 50 include a keyboard, a mouse, and a drive device that can read files, etc.

[0026] The output unit 52 is an output interface that provides the user with the determination result of the driving determination unit 40. Examples of the output unit 52 include a display device, an audio output device such as a speaker, and a drive device capable of writing files. The output unit 52 may also have the function of the input unit 50, such as a touch panel.

[0027] The performance degradation amount update unit 60 is a functional element that updates the performance degradation amount information stored in the storage unit 30, for example, by using new performance degradation amount information received by the input unit 50 or new performance degradation amount information output by the performance degradation amount measurement unit 126. The performance degradation amount update unit 60 may perform the update operation in response to an instruction from the input unit 50, or may perform the update operation based on a preset timing or cycle.

[0028] The operation control unit 70 is a functional element that can control the operation of the fuel cell 2. The operation control unit 70 may have a function of switching the operating state of the fuel cell 2 between grid-connected operation and stand-alone operation. The operation control unit 70 transmits command signals to the power generation control unit 110 and the operation switching unit 120 to control the operation of the fuel cell stack 100 and switch the operating state.

[0029] The environment acquisition unit 80 is a functional element that acquires, for example, environmental information around the fuel cell 2 or the fuel cell stack 100. Examples of the environmental information acquired by the environment acquisition unit 80 include weather forecast data such as device temperature, air temperature, and humidity.

[0030] The power outage determination unit 90 is a functional element that determines whether there is a risk of a power outage for the fuel cell stack 100, based on the environmental information acquired by the environment acquisition unit 80. For example, if there is forecast information about a typhoon or forecast information about prolonged sub-zero temperatures, there is a possibility that the fuel cell stack 100 will stop operating. In such cases, the power outage determination unit 90 determines that there is a risk of a power outage.

[0031] (Operation example of the first embodiment) Next, an example of the operation of the fuel cell control system 3 of the first embodiment will be described with reference to FIG.

[0032] The memory unit 30 stores performance degradation information including the amount of degradation in the power generation performance of the fuel cell stack 100 when the operation of the fuel cell 2 is stopped, and the amount of degradation in the power generation performance of the fuel cell stack 100 per unit time when the fuel cell 2 is operating (S200).

[0033] The performance degradation amount information may be stored in advance in the storage unit 30, or may be performance degradation amount information received from a user via the input unit 50. Furthermore, the performance degradation amount information may be information measured by the performance degradation amount measurement unit 126 based on the measurement results of the generated power measurement unit 122 and stored as the performance degradation amount information, or may be performance degradation amount information updated by the performance degradation amount update unit 60.

[0034] Next, the power demand acquisition unit 12 acquires the time-series change in the power supply from the fuel cell 2 (fuel cell stack 100) (S210). The acquired result here is the power demand of the fuel cell 2. The power demand acquisition unit 12 may acquire the power demand in real time or at regular intervals. The acquired real-time power demand result is continuous data, and the acquired power demand at regular intervals is discrete value data.

[0035] The learning calculation unit 20 performs learning calculations on the time series changes in the power supply from the fuel cell 2 acquired by the power demand acquisition unit 12, and stores the result in the learning database 22 as a time series pattern of the power demand (S220).

[0036] The operation determination unit 40 determines whether the power demand acquired by the power demand acquisition unit 12 is less than the minimum power generation output (S230). That is, the operation determination unit 40 determines whether the power generation required of the fuel cell 2 based on the power demand has become less than the minimum power generation output of the fuel cell 2, thereby requiring the operation to be stopped. If the determination result shows that the state has not been reached where the operation of the fuel cell stack 100 requires the operation to be stopped (No in S230), the power demand acquisition unit 12 continues to acquire the power demand, and the learning calculation unit 20 continues to learn the time series pattern of the power demand (S200 to S220).

[0037] If the result of the determination is that the power demand of the fuel cell stack 100 is less than the minimum power generation output of the fuel cell stack 100 (Yes in S230), that is, if a state has been reached where it is necessary to stop operation of the fuel cell 2, the operation determination unit 40 determines whether or not to stop operation of the fuel cell stack 100 based on the time series pattern of the power demand stored in the learning database 22 and the performance degradation information stored in the memory unit 30 (S240).

[0038] If the judgment result is to continue operation (No in S240), that is, if the current state has reached a point where it is necessary to stop operation of the fuel cell 2 but continuing operation of the fuel cell 2 would result in a smaller decrease in power generation performance than stopping operation, the fuel cell stack 100 will continue to generate power, the power demand acquisition unit 12 will continue to acquire the amount of power demand, and the learning calculation unit 20 will continue to learn the time series pattern of the amount of power demand.

[0039] If the judgment result is that operation should be stopped (Yes in S240), that is, if stopping the operation of the fuel cell 2 would result in a smaller decrease in power generation performance than continuing operation, the operation control unit 70 outputs a command signal to stop operation to the power generation control unit 110, and the power generation control unit 110 stops power generation by the fuel cell stack 100 (S250).

[0040] In the above embodiment, the learning calculation unit 20 generates a time series pattern of power demand by learning calculation and stores it in the learning database 22, but this is not limiting. The learning calculation unit 20 may also receive a time series pattern of power demand generated by another learning calculation device from the input unit 50 and store it in the learning database 22.

[0041] In this way, according to the fuel cell control system of this embodiment, it is possible to suppress the deterioration of the power generation performance of the fuel cell stack by determining whether or not to stop the operation of the fuel cell based on the time series pattern of the power demand that can be generated by the learning calculation and the performance degradation amount information regarding the deterioration amount of the power generation performance of the fuel cell stack.

[0042] (Operation example of the second embodiment) Next, the operation of the second embodiment of the present invention will be described with reference to Fig. 3. The fuel cell system of this embodiment has a common configuration with the fuel cell system 1 of the first embodiment. In the following description, common components are denoted by common reference numerals, and duplicated explanations will be omitted. Fig. 3 is a flowchart showing an example of the operation of the fuel cell control system of the second embodiment. This embodiment relates to the operation of the operation stop determination (S240) in the first embodiment.

[0043] The operation determination unit 40 determines whether the power demand acquired by the power demand acquisition unit 12 is less than the minimum power generation output (S230). That is, the operation determination unit 40 determines whether the power generation required of the fuel cell 2 based on the power demand has become less than the minimum power generation output of the fuel cell 2, thereby requiring the operation to be stopped. If the determination result shows that the state has not been reached where the operation of the fuel cell stack 100 requires the operation to be stopped (No in S230), the power demand acquisition unit 12 continues to acquire the power demand, and the learning calculation unit 20 continues to learn the time series pattern of the power demand.

[0044] If the result of the determination is that the power demand of the fuel cell stack 100 is less than the minimum power generation output of the fuel cell stack 100 (Yes in S230), that is, if a state has been reached where it is necessary to stop operation of the fuel cell 2, the operation determination unit 40 determines whether or not to stop operation of the fuel cell stack 100 based on the time series pattern of the power demand stored in the learning database 22 and the performance degradation information stored in the memory unit 30.

[0045] The operation determination unit 40 predicts the time (low demand period) when the power demand will be less than the minimum power generation output of the fuel cell stack 100 (S241). Based on the time series pattern of the power demand stored in the learning database 22, the operation determination unit 40 predicts how long this state will be maintained from the time when the power demand became less than the minimum power generation output.

[0046] Next, the operation determination unit 40 calculates the amount of performance degradation based on the predicted low-demand period and the performance degradation amount information stored in the memory unit 30 (S242). The operation determination unit 40 first calculates the amount of degradation in power generation performance of the fuel cell stack 100 when the operation of the fuel cell 2 is stopped during the low-demand period and then restarted (amount of performance degradation during operation suspension). Next, the operation determination unit 40 calculates a value (amount of performance degradation during continued operation) obtained by multiplying the amount of degradation in power generation performance per unit time of the fuel cell stack 100 when the fuel cell 2 continues to operate by the low-demand period.

[0047] The operation determination unit 40 compares the amount of performance degradation due to operation suspension with the amount of performance degradation due to continued operation (S243). If the comparison results in the amount of performance degradation due to operation suspension being smaller than the amount of performance degradation due to continued operation, meaning that the amount of performance degradation is greater in continued operation (Yes in S243), the operation determination unit 40 determines to stop operation (S244). The operation control unit 70 outputs a command signal to stop operation to the power generation control unit 110, and the power generation control unit 110 stops power generation by the fuel cell stack 100 (S250).

[0048] As a result of the comparison, if the amount of degradation in the shutdown performance is equal to or greater than the amount of degradation in the continued operation performance (No in S243), the operation determination unit 40 determines to continue operation (S245).

[0049] In this way, according to the fuel cell control system of this embodiment, the amount of degradation in performance when the fuel cell is stopped and the amount of degradation in performance when the fuel cell is continued are calculated based on the time series pattern of power demand that can be generated by learning calculations, and a comparison of these amounts determines whether or not the fuel cell should be stopped, thereby autonomously suppressing degradation in the power generation performance of the fuel cell stack.

[0050] (Operation example of the third embodiment) Next, the operation of a third embodiment of the present invention will be described with reference to Fig. 4. The fuel cell system of this embodiment has a common configuration with the fuel cell system 1 of the first embodiment. In the following description, common components are denoted by common reference numerals, and duplicated explanations will be omitted. Figs. 4 and 5 are flowcharts showing an example of the operation of a fuel cell control system according to the third embodiment. This embodiment adds the operation of an environment acquisition unit 80 to the operation of the first or second embodiment. The following description will be given assuming that this is applied to the second embodiment.

[0051] The environment acquisition unit 80 acquires weather forecast data as the environment information (S225). The weather forecast data includes information indicating the change in the temperature around the fuel cell 2.

[0052] The operation determination unit 40 determines whether the power demand acquired by the power demand acquisition unit 12 is less than the minimum power generation output (S230). That is, the operation determination unit 40 determines whether the power generation required of the fuel cell 2 based on the power demand has become less than the minimum power generation output of the fuel cell 2, thereby requiring the operation to be stopped. If the determination result shows that the state has not been reached where the operation of the fuel cell stack 100 requires the operation to be stopped (No in S230), the power demand acquisition unit 12 continues to acquire the power demand, the learning calculation unit 20 continues to learn the time series pattern of the power demand, and the environment acquisition unit 80 acquires weather forecast data as environment information (S225).

[0053] If the result of the determination is that the power demand of the fuel cell stack 100 is less than the minimum power generation output of the fuel cell stack 100 (Yes in S230), that is, if a state has been reached where it is necessary to stop operation of the fuel cell 2, the environment acquisition unit 80 determines whether or not there is a prediction that the temperature in the environment surrounding the fuel cell 2 will fall below freezing (S235).

[0054] If there is no prediction that the temperature will drop below freezing (No in S235), the operation judgment unit 40 judges whether or not to stop operation of the fuel cell stack 100 based on the time series pattern of power demand stored in the learning database 22 and the performance degradation information stored in the memory unit 30.

[0055] The operation determination unit 40 predicts the time (low demand period) when the power demand will be less than the minimum power generation output of the fuel cell stack 100 (S241). Based on the time series pattern of the power demand stored in the learning database 22, the operation determination unit 40 predicts how long this state will be maintained from the time when the power demand became less than the minimum power generation output.

[0056] Next, the operation determination unit 40 calculates the amount of performance degradation based on the predicted low-demand period and the performance degradation amount information stored in the storage unit 30 (S242). The operation determination unit 40 first calculates the amount of performance degradation due to shutdown of the fuel cell stack 100 when operation of the fuel cell 2 is stopped during the low-demand period. Next, the operation determination unit 40 calculates the amount of performance degradation due to continued operation.

[0057] The operation determination unit 40 compares the amount of performance degradation due to operation suspension with the amount of performance degradation due to continued operation (S243). If the comparison results in the amount of performance degradation due to operation suspension being smaller than the amount of performance degradation due to continued operation, meaning that the amount of performance degradation is greater in continued operation (Yes in S243), the operation determination unit 40 determines to stop operation (S244). The operation control unit 70 outputs a command signal to stop operation to the power generation control unit 110, and the power generation control unit 110 stops power generation by the fuel cell stack 100 (S250).

[0058] If the comparison result shows that the amount of performance degradation in stopping operation is less than or equal to the amount of performance degradation in continuing operation (No in S243), and if there is a prediction that the temperature will be below freezing (Yes in S235), the operation determination unit 40 determines to continue operation (S245).

[0059] In the example described above, the operation determination unit 40 continues operation of the fuel cell 2 when freezing is predicted based on the weather forecast data acquired by the environment acquisition unit 80, but this is not limited to this. For example, the operation control unit 70 may be configured to have two operation modes for the fuel cell 2: an operation priority mode that prioritizes operation to prevent the life of the fuel cell 2 or freezing of the fuel cell 2, and a consumption priority mode that prioritizes reducing the amount of hydrogen consumed by the fuel cell stack 100, and the mode of the operation control unit 70 may be used as a determination condition.

[0060] For example, as shown in FIG. 5, when the operation determination unit 40 determines to continue operation (S245), the operation control unit 70 determines whether its state is the operation priority mode or the consumption priority mode (S246).

[0061] When the operation control unit 70 is in the consumption priority mode (Yes in S246), even if the determination result of the operation determination unit 40 is to continue operation, the operation control unit 70 outputs a command signal to stop operation to the power generation control unit 110, and the power generation control unit 110 stops power generation by the fuel cell stack 100 (S250). This makes it possible to realize control according to the preset priority order of anti-freeze and fuel consumption.

[0062] In this way, the fuel cell control system of this embodiment acquires weather forecast data including temperature changes in the surrounding environment of the fuel cell, and determines whether to continue operation depending on whether freezing is predicted, thereby preventing the fuel cell from freezing while autonomously suppressing a decline in the power generation performance of the fuel cell stack.

[0063] (Operation example of the fourth embodiment) Next, the operation of a fourth embodiment of the present invention will be described with reference to Fig. 6. The fuel cell system of this embodiment has a common configuration with the fuel cell system 1 of the first embodiment. In the following description, common components are denoted by common reference numerals, and duplicated explanations will be omitted. Fig. 6 is a flowchart showing an example of the operation of a fuel cell control system according to the fourth embodiment. This embodiment relates to the use of weather forecast data in the third embodiment.

[0064] The environment acquisition unit 80 acquires weather forecast data as the environment information (S225). The weather forecast data includes information indicating the change in the temperature around the fuel cell 2.

[0065] The operation determination unit 40 determines whether the power demand acquired by the power demand acquisition unit 12 is less than the minimum power generation output (S230). That is, the operation determination unit 40 determines whether the power generation required of the fuel cell 2 based on the power demand has become less than the minimum power generation output of the fuel cell 2, thereby requiring the operation to be stopped. If the determination result shows that the state has not been reached where the operation of the fuel cell stack 100 requires the operation to be stopped (No in S230), the power demand acquisition unit 12 continues to acquire the power demand, the learning calculation unit 20 continues to learn the time series pattern of the power demand, and the environment acquisition unit 80 acquires weather forecast data as environment information (S225).

[0066] If the result of the determination is that the power demand of the fuel cell stack 100 is less than the minimum power generation output of the fuel cell stack 100 (Yes in S230), that is, if a state has been reached where it is required to stop the operation of the fuel cell 2, the power outage determination unit 90 determines whether there is a risk of a power outage for the power system connected to the fuel cell 2 based on the weather forecast data acquired by the environment acquisition unit 80 (S231). The determination of whether there is a risk of a power outage can be made based on criteria such as whether there is a forecast of the temperature dropping below freezing, whether there is a forecast of lightning or the like, and whether there is typhoon information.

[0067] If the power outage determination unit 90 determines that there is a risk of power outage (Yes in S231), the operation control unit 70 determines whether the operation switching unit 120 of the fuel cell 2 has an uninterruptible switching function (S236).

[0068] If the operation switching unit 120 has the uninterruptible switching function, the operation control unit 70 outputs a command signal to the operation switching unit 120 to perform grid-connected operation (S237). If the operation switching unit 120 does not have the uninterruptible switching function, the operation control unit 70 outputs a command signal to the operation switching unit 120 to perform independent operation (S238). Whether or not the operation switching unit 120 has the uninterruptible switching function can be determined by storing information indicating the presence or absence of the function in the storage unit 30 in advance.

[0069] If the power outage determination unit 90 determines that there is no risk of power outage (No in S231), the environment acquisition unit 80 determines whether or not the temperature in the environment surrounding the fuel cell 2 is predicted to drop below freezing (S235).

[0070] If there is no prediction that the temperature will drop below freezing (No in S235), the operation judgment unit 40 judges whether or not to stop operation of the fuel cell stack 100 based on the time series pattern of power demand stored in the learning database 22 and the performance degradation information stored in the memory unit 30.

[0071] The operation determination unit 40 predicts the time (low demand period) when the power demand will be less than the minimum power generation output of the fuel cell stack 100 (S241). Based on the time series pattern of the power demand stored in the learning database 22, the operation determination unit 40 predicts how long this state will be maintained after the power demand becomes less than the minimum power generation output.

[0072] Next, the operation determination unit 40 calculates the amount of performance degradation based on the predicted low-demand period and the performance degradation amount information stored in the storage unit 30 (S242). The operation determination unit 40 first calculates the amount of performance degradation due to shutdown of the fuel cell stack 100 when operation of the fuel cell 2 is stopped during the low-demand period. Next, the operation determination unit 40 calculates the amount of performance degradation due to continued operation.

[0073] The operation determination unit 40 compares the amount of performance degradation due to operation suspension with the amount of performance degradation due to continued operation (S243). If the comparison results in the amount of performance degradation due to operation suspension being smaller than the amount of performance degradation due to continued operation, meaning that the amount of performance degradation is greater in continued operation (Yes in S243), the operation determination unit 40 determines to stop operation (S244). The operation control unit 70 outputs a command signal to stop operation to the power generation control unit 110, and the power generation control unit 110 stops power generation by the fuel cell stack 100 (S250).

[0074] As a result of the comparison, if the amount of degradation in operation stop performance is equal to or greater than the amount of degradation in operation continuation performance (No in S243), if the temperature is predicted to drop below freezing (Yes in S235), or if there is a risk of power outage (Yes in S231, S237, S238), the operation determination unit 40 determines to continue operation (S245). That is, in this embodiment, if there is a risk of power outage, the determination is always to continue operation.

[0075] In this way, the fuel cell control system of this embodiment determines whether to continue operation if there is a risk of a power outage, thereby preventing the fuel cell from freezing, avoiding the risk of a power outage, and autonomously suppressing a decline in the power generation performance of the fuel cell stack.

[0076] Furthermore, according to the fuel cell control system of this embodiment, the system switches between grid-connected operation and stand-alone operation depending on whether or not the operation switching unit 120 in the fuel cell has a power interruption-free switching function, thereby preventing accidents that may occur in grid-connected operation when there is a risk of power outage.

[0077] (Operation example of the fifth embodiment) Next, the operation of the fifth embodiment of the present invention will be described with reference to Fig. 7. The fuel cell system of this embodiment has a common configuration with the fuel cell system 1 of the first embodiment. In the following description, common configurations are denoted by common reference numerals, and duplicated explanations will be omitted. Fig. 7 is a flowchart showing an example of the operation of the fuel cell control system according to the fifth embodiment. This embodiment is a modification of the operation examples of the first to fourth embodiments. In the following description, it will be described as being applied to the first embodiment.

[0078] The memory unit 30 stores performance degradation information including the amount of degradation in the power generation performance of the fuel cell stack 100 when the operation of the fuel cell 2 is stopped, and the amount of degradation in the power generation performance of the fuel cell stack 100 per unit time when the fuel cell 2 is operating (S200).

[0079] The performance degradation amount information may be stored in advance in the storage unit 30, or may be received from a user via the input unit 50 and stored. Furthermore, the performance degradation amount information may be information measured by the performance degradation amount measurement unit 126 based on the measurement results of the generated power measurement unit 122 and stored as the performance degradation amount information, or may be performance degradation amount information updated by the performance degradation amount update unit 60.

[0080] Next, the power demand acquisition unit 12 acquires the time-series change in the power supply from the fuel cell 2 (fuel cell stack 100) (S210). The acquired result here is the power demand of the fuel cell 2. The power demand acquisition unit 12 may acquire the power demand in real time or at regular intervals. The acquired real-time power demand result is continuous data, and the acquired power demand at regular intervals is discrete value data.

[0081] The learning calculation unit 20 performs learning calculations on the time series changes in the power supply from the fuel cell 2 acquired by the power demand acquisition unit 12, and stores the result in the learning database 22 as a time series pattern of the power demand (S220).

[0082] The operation determination unit 40 determines whether the power demand acquired by the power demand acquisition unit 12 is less than the minimum power generation output (S230). That is, the operation determination unit 40 determines whether the power generation required of the fuel cell 2 based on the power demand has become less than the minimum power generation output of the fuel cell 2, thereby requiring the operation to be stopped. If the determination result shows that the state has not been reached where the operation of the fuel cell stack 100 requires the operation to be stopped (No in S230), the power demand measurement unit 12 continues to acquire the power demand, and the learning calculation unit 20 continues to learn the time series pattern of the power demand (S200 to S220).

[0083] If the result of the determination is that the power demand of the fuel cell stack 100 is less than the minimum power generation output of the fuel cell stack 100 (Yes in S230), that is, if a state has been reached where it is necessary to stop operation of the fuel cell 2, the operation determination unit 40 determines whether or not to stop operation of the fuel cell stack 100 based on the time series pattern of power demand stored in the learning database 22 and the performance degradation information stored in the memory unit 30 (S240).

[0084] If the judgment result is to continue operation (No in S240), that is, if the current state has reached a point where it is necessary to stop operation of the fuel cell 2 but continuing operation of the fuel cell 2 would result in a smaller decrease in power generation performance than stopping operation, the fuel cell stack 100 will continue to generate power, the power demand measurement unit 12 will continue to acquire the amount of power demand, and the learning calculation unit 20 will continue to learn the time series pattern of the amount of power demand (S200 to S220).

[0085] If the judgment result is to stop operation (Yes in S240), that is, if stopping operation of the fuel cell 2 results in a smaller decrease in power generation performance than continuing operation, the output unit 52, which serves as a display device, displays the judgment result of the operation judgment unit 40 (S247).

[0086] The input unit 50 as an input device waits for the user's approval input (S248). If the received input does not approve the determination result of the driving determination unit 40 (No in S248), the determination process of the driving determination unit 40 is repeated (S230, S240).

[0087] If the received input approves the judgment result of the operation judgment unit 40 (Yes in S248), the operation control unit 70 outputs a command signal to stop operation to the power generation control unit 110, and the power generation control unit 110 stops power generation by the fuel cell stack 100 (S250).

[0088] In the above-described embodiment, the processing of the output unit 52 and the input unit 50 is applied to the fuel cell control system of the first embodiment, but is not limited to this. It may also be applied to the fuel cell control systems of the second to fourth embodiments. That is, the instruction received by the input unit 50 is not limited to approval of the determination of whether or not to stop operation. For example, it may be an instruction to select either grid-connected operation or stand-alone operation.

[0089] Thus, according to the fuel cell control system of this embodiment, the judgment result is presented to the user and the fuel cell operation stop control is executed after receiving approval, thereby realizing operation control in line with the user's wishes.

[0090] (Sixth embodiment) Next, a sixth embodiment of the present invention will be described with reference to Figs. 8 and 9. A fuel cell system 1a of this embodiment is configured by adding a battery capable of supporting the fuel cells of the first to fifth embodiments. In the following description, common components are denoted by common reference numerals, and duplicated explanations will be omitted. Fig. 8 is a block diagram showing the functional configuration of a fuel cell control system according to the sixth embodiment. Fig. 9 is a flowchart showing an example of the operation of the fuel cell control system according to the sixth embodiment. As shown in Fig. 8, the fuel cell 2a of this embodiment includes a battery 130. The power generation control unit 110 is configured to be able to control the discharge output of the battery 130 as well.

[0091] (Operation example of the sixth embodiment) Next, the operation of the sixth embodiment of the present invention will be described with reference to Fig. 9. The operation determination unit 40 determines whether the power demand acquired by the power demand acquisition unit 12 is less than the minimum power generation output (S230). That is, the operation determination unit 40 determines whether the power generation output required of the fuel cell 2 based on the power demand is less than the minimum power generation output of the fuel cell 2, thereby requiring the operation to be stopped. If the determination result shows that the state has not been reached where the operation of the fuel cell stack 100 requires the operation to be stopped (No in S230), the power demand measurement unit 12 continues to acquire the power demand, and the learning calculation unit 20 continues to learn the time series pattern of the power demand.

[0092] If the result of the determination is that the power demand of the fuel cell stack 100 is less than the minimum power generation output of the fuel cell stack 100 (Yes in S230), that is, if a state has been reached where it is necessary to stop operation of the fuel cell 2, the operation determination unit 40 determines whether or not to stop operation of the fuel cell stack 100 based on the time series pattern of the power demand stored in the learning database 22 and the performance degradation information stored in the memory unit 30.

[0093] The operation determination unit 40 predicts the time (low demand period) when the power demand will be less than the minimum power generation output of the fuel cell stack 100 (S241). Based on the time series pattern of the power demand stored in the learning database 22, the operation determination unit 40 predicts how long this state will be maintained from the time when the power demand became less than the minimum power generation output.

[0094] Next, the operation determination unit 40 calculates the amount of performance degradation based on the predicted low-demand period and the performance degradation amount information stored in the storage unit 30 (S242). The operation determination unit 40 first calculates the amount of performance degradation due to shutdown of the fuel cell stack 100 when operation of the fuel cell 2 is stopped during the low-demand period. Next, the operation determination unit 40 calculates the amount of performance degradation due to continued operation.

[0095] The operation determination unit 40 compares the amount of performance degradation due to operation suspension with the amount of performance degradation due to continued operation (S243). If the comparison results in the amount of performance degradation due to operation suspension being smaller than the amount of performance degradation due to continued operation, meaning that the amount of performance degradation is greater in continued operation (Yes in S243), the operation determination unit 40 determines to stop operation (S244). The operation control unit 70 outputs a command signal to stop operation to the power generation control unit 110, and the power generation control unit 110 stops power generation by the fuel cell stack 100 (S250).

[0096] If the comparison result shows that the amount of performance degradation in operation suspension is equal to or greater than the amount of performance degradation in operation continuation (No in S243), the operation determination unit 40 determines to continue operation (S245). The operation control unit 70 outputs a command signal to the power generation control unit 110 of the fuel cell 2 to increase the output of the battery 130. The power generation control unit 110 increases the discharge output of the battery 130 and reduces the amount of power generated by the fuel cell stack 100 to save fuel (S249).

[0097] As described above, according to the fuel cell control system of this embodiment, when it is determined that operation should continue, control is executed to increase the discharge amount of the battery that assists the fuel cell stack 100. In other words, during periods of low demand when the amount of power demand is below the minimum power generation output, the battery is able to absorb the power generated by the fuel cell, and fuel consumption can also be reduced.

[0098] Seventh embodiment Next, a seventh embodiment of the present invention will be described with reference to Figs. 10 and 11. A fuel cell system 1b of this embodiment further comprises a functional element that manages the fuel of the fuel cells of the first to fifth embodiments. In the following description, common components are denoted by common reference numerals, and duplicated explanations will be omitted. Fig. 10 is a block diagram showing the functional configuration of a fuel cell control system according to the seventh embodiment. Fig. 11 is a flowchart showing an example of the operation of the fuel cell control system according to the seventh embodiment. As shown in Fig. 10, a fuel cell control system 3b of this embodiment comprises a fuel management unit 95. The fuel management unit 95 is a functional element that can manage the amount of fuel stored in the fuel cell stack 100.

[0099] (Example of operation of the seventh embodiment) Next, the operation of the seventh embodiment of the present invention will be described with reference to FIG.

[0100] The operation determination unit 40 determines whether the power demand acquired by the power demand acquisition unit 12 is less than the minimum power generation output (S230). That is, the operation determination unit 40 determines whether the power generation required of the fuel cell 2 based on the power demand has become less than the minimum power generation output of the fuel cell 2, thereby requiring the operation to be stopped. If the determination result shows that the state has not been reached where the operation of the fuel cell stack 100 requires the operation to be stopped (No in S230), the power demand acquisition unit 12 continues to acquire the power demand, and the learning calculation unit 20 continues to learn the time series pattern of the power demand.

[0101] If the result of the determination is that the power demand of the fuel cell stack 100 is less than the minimum power generation output of the fuel cell stack 100 (Yes in S230), that is, if a state has been reached where it is necessary to stop operation of the fuel cell 2, the operation determination unit 40 determines whether or not to stop operation of the fuel cell stack 100 based on the time series pattern of the power demand stored in the learning database 22 and the performance degradation information stored in the memory unit 30.

[0102] The operation determination unit 40 predicts the time (low demand period) when the power demand will be less than the minimum power generation output of the fuel cell stack 100 (S241). Based on the time series pattern of the power demand stored in the learning database 22, the operation determination unit 40 predicts how long this state will be maintained from the time when the power demand became less than the minimum power generation output.

[0103] Next, the operation determination unit 40 calculates the amount of performance degradation based on the predicted low-demand period and the performance degradation amount information stored in the storage unit 30 (S242). The operation determination unit 40 first calculates the amount of performance degradation due to shutdown of the fuel cell stack 100 when operation of the fuel cell 2 is stopped during the low-demand period. Next, the operation determination unit 40 calculates the amount of performance degradation due to continued operation.

[0104] The operation determination unit 40 compares the amount of performance degradation due to operation suspension with the amount of performance degradation due to continued operation (S243). If the comparison results in the amount of performance degradation due to operation suspension being smaller than the amount of performance degradation due to continued operation, meaning that the amount of performance degradation is greater in continued operation (Yes in S243), the operation determination unit 40 determines to stop operation (S244). The operation control unit 70 outputs a command signal to stop operation to the power generation control unit 110, and the power generation control unit 110 stops power generation by the fuel cell stack 100 (S250).

[0105] As a result of the comparison, if the amount of degradation in the shutdown performance is equal to or greater than the amount of degradation in the continued operation performance (No in S243), the operation determination unit 40 determines to continue operation (S245).

[0106] The fuel management unit 95 acquires the amount of fuel stored in the fuel cell stack 100 and determines whether it has fallen below a predetermined amount (S260). If the result of the determination is that the amount of fuel stored in the fuel cell stack 100 exceeds the predetermined amount (No in S260), the determination to continue operation is maintained.

[0107] If the determination result shows that the amount of fuel stored in the fuel cell stack 100 has fallen below a predetermined amount (Yes in S260), the operation control unit 70 outputs a command signal to the power generation control unit 110 to reduce the power generation output of the fuel cell stack 100 (S262). Upon receiving the command signal, the power generation control unit 110 reduces the power generation output of the fuel cell stack 100 to reduce fuel consumption. Here, the predetermined amount of storage is, for example, the amount of fuel consumed during the time when the determination to continue operation is made.

[0108] As described above, the fuel cell control system of this embodiment is configured to be able to adjust the power generation output of the fuel cell based on the amount of fuel stored in the fuel cell, thereby making it possible to save fuel and extend the operating duration.

[0109] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0110] 1... fuel cell system, 2... fuel cell, 3... fuel cell control system, 10... power measurement unit, 20... learning calculation unit, 22... learning database, 30... memory unit, 40... operation determination unit, 50... input unit, 52... output unit, 60... performance degradation amount meter unit, 62... performance degradation amount update unit, 70... operation control unit, 80... environment acquisition unit, 90... power outage determination unit, 95... fuel management unit, 100... fuel cell stack, 110... power generation control unit, 120... operation switching unit, 130... battery

Claims

1. A fuel cell control system for controlling a fuel cell having a fuel cell stack that generates electric power through a chemical reaction, an electric power demand acquisition unit that acquires the electric power demand of the fuel cell at a supply destination of the fuel cell; a learning calculation unit that learns and stores a time series pattern of the power demand amount based on the result of acquisition by the power demand acquisition unit; a storage unit that stores performance degradation amount information indicating the amount of performance degradation of the fuel cell stack; an operation determination unit that determines whether or not to stop operation of the fuel cell based on the time series pattern of the power demand and the performance degradation amount information; A fuel cell control system comprising:

2. further comprising a data input unit capable of inputting a time series pattern of the power demand, The learning calculation unit holds the input results of the data input unit.

2. The fuel cell control system according to claim 1, wherein:

3. 2. The fuel cell control system according to claim 1, further comprising a cell information acquisition unit capable of acquiring the performance degradation amount information from the fuel cell.

4. 2. The fuel cell control system according to claim 1, further comprising a performance degradation amount update unit that updates the performance degradation amount information stored in the memory unit based on the performance degradation amount information acquired by the battery information acquisition unit.

5. 2. The fuel cell control system according to claim 1, wherein the performance degradation information includes the amount of degradation in the power generation performance of the fuel cell stack when the operation of the fuel cell is stopped and the amount of degradation in the power generation performance of the fuel cell stack per unit time when the fuel cell is operating.

6. an operation control unit that controls the operation of the fuel cell based on the determination result of the operation determination unit; the battery information acquisition unit further acquires the output power of the fuel cell stack; The driving determination unit predicting a low demand period in which the amount of power demand will be equal to or less than a predetermined value based on a time series pattern of the amount of power demand; comparing the amount of decrease in power generation performance of the fuel cell stack when the operation of the fuel cell is stopped with the amount of decrease in power generation performance of the fuel cell stack per unit time when the fuel cell is operating based on the output power and the predicted low demand period; determining whether to stop or continue operation of the fuel cell so as to minimize the amount of degradation in the power generation performance of the fuel cell stack; 2. The fuel cell control system according to claim 1, wherein:

7. further comprising an environment acquisition unit that acquires weather forecast data; The operation determination unit determines to continue operation of the fuel cell when freezing of the fuel cell stack is predicted based on the weather forecast data.

7. The fuel cell control system according to claim 6, wherein:

8. the operation control unit has two states: an operation priority mode in which priority is given to operation to prolong the life of the fuel cell or to prevent freezing of the fuel cell, and a consumption priority mode in which priority is given to reducing fuel consumption; the operation control unit, when in the consumption priority mode, stops the operation of the fuel cell even if the determination result of the operation determination unit is to continue the operation of the fuel cell; 8. The fuel cell control system according to claim 7, wherein:

9. an environment acquisition unit that acquires weather forecast data; a power outage determination unit that can determine whether or not there is a power outage risk in the fuel cell connected to the grid based on the weather forecast data; Furthermore, When the power outage determination unit determines that there is a risk of a power outage, the operation control unit continues operation of the fuel cell regardless of the determination result of the operation determination unit.

7. The fuel cell control system according to claim 6, wherein:

10. the storage unit further stores operation switching information indicating whether the fuel cell can switch between grid-connected operation and stand-alone operation without momentary interruption; When the power outage determination unit determines that there is a risk of power outage, the operation control unit causes the fuel cell to operate in a grid-connected manner if the operation switching information indicates that uninterruptible switching is possible, and causes the fuel cell to operate in an independent manner if the operation switching information indicates that uninterruptible switching is not possible.

10. The fuel cell control system according to claim 9, wherein:

11. an output unit capable of outputting a determination result of the driving determination unit; an instruction input unit capable of receiving instructions from a user; Furthermore, The operation control unit controls the operation of the fuel cell in accordance with the instruction content of the instruction input unit.

11. The fuel cell control system according to claim 1, wherein:

12. An output unit capable of outputting the determination result of the power outage determination unit; an instruction input unit capable of receiving instructions from a user; Furthermore, The operation control unit executes the grid-connected operation or the stand-alone operation in accordance with the instruction content received by the instruction input unit.

11. The fuel cell control system according to claim 10,

13. Further comprising a battery capable of supplementing the output power of the fuel cell; The operation control unit is capable of adjusting the output power of the fuel cell and the output power of the battery when the determination result of the operation determination unit is to continue the operation of the fuel cell.

11. The fuel cell control system according to claim 1, wherein:

14. a fuel management unit capable of managing the amount of fuel stored in the fuel cell; The operation control unit is capable of adjusting the output power of the fuel cell when the determination result of the operation determination unit is to continue operation of the fuel cell and the amount of stored fuel is equal to or less than a predetermined value.

11. The fuel cell control system according to claim 1, wherein:

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