Fuel cell device

Abstract

A fuel cell device comprises a fuel cell, a combustion unit, an acquisition unit, a first detection unit, and a control unit. The fuel cell generates electric power using a fuel gas. The combustion unit burns fuel gas that has not reacted in the fuel cell. The acquisition unit acquires an electric power generation amount generated by the fuel cell. The first detection unit detects the temperature of the combustion unit. When the temperature detected by the first detection unit deviates from a temperature range corresponding to the electric power generation amount acquired by the acquisition unit, the control unit performs control so as to change the electric power generation amount of the fuel cell.

Description

fuel cell device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2024-020664, filed on February 14, 2024, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to fuel cell devices.

[0003] In a fuel cell device including a fuel cell such as a solid oxide fuel cell, fuel is used not only to generate electricity in the fuel cell but also to provide heat necessary for stabilizing the temperature of the fuel cell, etc. Therefore, in a fuel cell device, adjusting the amount of fuel supplied affects not only the power generated but also the temperature of each part of the fuel cell, etc. (See Patent Document 1).

[0004] Patent No. 5528451

[0005] A fuel cell device according to a first aspect comprises a solid oxide fuel cell that generates electricity using fuel gas; a combustion unit that combusts the unreacted fuel gas in the fuel cell; an acquisition unit that acquires the amount of electricity generated by the fuel cell; a first detection unit that detects the temperature of the combustion unit; and a control unit that controls the amount of electricity generated by the fuel cell to change if the temperature detected by the first detection unit falls outside a temperature range corresponding to the amount of electricity generated acquired by the acquisition unit in a correspondence relationship between the amount of electricity generated by the fuel cell and the temperature range of the combustion unit that is predetermined.

[0006] The present invention relates to a fuel cell device and a fuel cell control system.

[0007] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same components are denoted by the same reference numerals.

[0008] 1 , a fuel cell device 10 according to an embodiment of the present disclosure includes a fuel cell 11, a combustion unit 12, an acquisition unit 13, a first detection unit 14, and a control unit 15. The fuel cell device 10 may further include a reformer 16, a first supply unit 17, and a second supply unit 18.

[0009] The fuel cell 11 generates power through an electrochemical reaction using fuel gas and air. Specifically, the fuel cell 11 performs an electrochemical reaction using oxygen gas in the air. The fuel cell 11 may include a fuel cell unit. The fuel cell 11 may include a plurality of fuel cell units. The plurality of fuel cell units may form a cell stack. The cell stack may have any shape, such as a hollow plate, a flat plate, a metal support, or a cylinder. The fuel cell unit is a solid oxide fuel cell unit. In the fuel cell 11, not all of the fuel gas and oxygen gas in the air may undergo an electrochemical reaction, and unreacted fuel gas and oxygen gas may be discharged. The discharged unreacted fuel gas may include methane that was not reformed in the reformer 16 described below.

[0010] The combustion unit 12 burns unreacted fuel gas in the fuel cell 11 using unreacted oxygen gas. The combustion unit 12 may heat the fuel cell 11 and the reformer 16 using heat generated by burning the unreacted fuel gas. The combustion unit 12 may heat the fuel cell 11 to stabilize the temperature of the fuel cell 11. The combustion unit 12 may heat the reformer 16 to provide energy for a steam reforming reaction in the reformer 16. The combustion unit 12 may be located in the opposite direction from the reformer 16 in the first direction to effectively heat the reformer 16. In the fuel cell device 10, the first direction is a direction in which the fuel cell device 10 is expected to be oriented vertically upward when installed. The combustion unit 12 may be, for example, a space in the first direction from the fuel cell 11. Unreacted fuel gas and unreacted oxygen gas injected from an outlet of the fuel cell 11 may be burned in this space. Alternatively, the combustion unit 12 may be, for example, a burner located in a first direction from the fuel cell 11 .

[0011] The acquisition unit 13 acquires the amount of power generated by the fuel cell 11 as information. The amount of power generated may be an instantaneous value of power, an amount of power per unit time, a time average value of the amount of power, etc. The acquisition unit 13 may acquire the amount of power generated by the fuel cell 11 by detecting it from the fuel cell 11. Alternatively, the acquisition unit 13 may acquire the amount of power generated by the fuel cell 11 by receiving it as information from a power adjustment unit 19 that adjusts the current value, etc., of the power generated by the fuel cell 11.

[0012] The power adjustment unit 19 adjusts the power generated by the fuel cell 11. The power adjustment unit 19 may adjust the current value based on, for example, the required load on the fuel cell device 10. The required load is a power value requested of the fuel cell device 10 by a consumer facility that uses the fuel cell device 10. When the power adjustment unit 19 obtains the required load as information from the consumer facility, it may notify the control unit 15 of the required load as information. The power adjustment unit 19 is, for example, a power conditioner. The power adjustment unit 19 may be arranged inside the housing of the fuel cell device 10 or outside the housing of the fuel cell device 10.

[0013] The first detector 14 detects the temperature of the combustion section 12. The first detector 14 is, for example, a temperature sensor such as a thermocouple or a thermistor.

[0014] The reformer 16 may generate fuel gas by steam reforming the methane concentration varying fuel and water. Specifically, the reformer 16 may contain a reforming catalyst. The reforming catalyst may generate fuel gas from the methane concentration varying fuel and water. Steam may be supplied to the reformer 16 as liquid reforming water and vaporized into steam in a vaporizer provided in the reformer 16. The fuel gas may include, for example, hydrogen gas.

[0015] The variable methane concentration fuel is, for example, biogas, and may be produced by fermentation of organic fertilizer, biodegradable materials, sludge, wastewater, etc. The variable methane concentration fuel mainly contains methane and carbon dioxide. The variable methane concentration fuel may have a variable methane concentration.

[0016] The first supply unit 17 may supply the fuel gas directly or indirectly to the fuel cell 11. For example, the first supply unit 17 may indirectly supply the fuel gas to the fuel cell 11 by supplying a variable methane concentration fuel to the reformer 16. In the following description, the fuel gas will be described as being indirectly supplied to the fuel cell 11 via the reformer 16. The first supply unit 17 may adjust the amount of fuel gas supplied. A specific maximum supply amount may be set for the first supply unit 17. The specific maximum supply amount may be a rated value for the first supply unit 17. The first supply unit 17 may be, for example, a pump with a variable duty ratio.

[0017] The second supply unit 18 may supply water to the reformer 16. The second supply unit 18 may adjust the amount of water supplied to the reformer 16. The second supply unit 18 may be, for example, a pump whose duty ratio is variable.

[0018] The control unit 15 is configured to include at least one processor, at least one dedicated circuit, or a combination of these. The processor is a general-purpose processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), or a dedicated processor specialized for specific processing. The dedicated circuit may be, for example, an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). The control unit 15 may control the operation of the fuel cell device 10.

[0019] The control unit 15 may further include a storage unit. The storage unit may include any storage device, such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The storage unit may store various programs that cause the control unit 15 to function and various information used by the control unit 15. For example, the storage unit may store a correspondence relationship between the amount of power generated by the fuel cell 11 and the temperature range of the combustion unit 12, which is predetermined for appropriate operation. The correspondence relationship may be, for example, a relational expression or a correspondence table.

[0020] The control unit 15 may determine a temperature range corresponding to the amount of power generation of the fuel cell 11 acquired by the acquisition unit 13. The control unit 15 may adjust the amount of fuel gas supplied so that the temperature detected by the first detection unit 14 falls within the determined temperature range. Specifically, the control unit 15 may control the first supply unit 17 to adjust the amount of fuel gas supplied.

[0021] When the temperature detected by the first detector 14 is outside the determined temperature range, the controller 15 controls the fuel cell 11 to change the amount of power generation. Specifically, the controller 15 may change the amount of power generation of the fuel cell 11 by sending an instruction to the power adjustment unit 19 to change the amount of power generation.

[0022] The control unit 15 may control the fuel cell 11 to increase the amount of power generation when the temperature detected by the first detection unit 14 exceeds the determined temperature range. Specifically, the control unit 15 may increase the amount of power generation by the fuel cell 11 by sending an instruction to increase power generation to the power adjustment unit 19. Increasing the amount of power generation reduces the amount of unreacted fuel gas consumed in the combustion unit 12. The reduction in the amount of fuel gas consumed may cause the temperature detected by the first detection unit 14 to fall within the determined temperature range.

[0023] Furthermore, when the amount of power generated by the fuel cell 11 is at its upper limit, the control unit 15 may reduce the amount of variable methane concentration fuel supplied to the fuel cell 11. When the amount of power generated by the fuel cell 11 has reached its upper limit, the amount of power generated cannot be increased any further. Therefore, by reducing the amount of fuel gas supplied to the fuel cell 11, the amount of unreacted fuel gas consumed in the combustion unit 12 can be reduced. By reducing the amount of fuel gas consumed, the temperature detected by the first detection unit 14 can fall within the determined temperature range.

[0024] On the other hand, when the temperature detected by the first detection unit 14 is below the determined temperature range, the control unit 15 may control the fuel cell 11 to reduce the amount of power generation. Specifically, the control unit 15 may reduce the amount of power generation by sending an instruction to the power adjustment unit 19 to reduce the amount of power generation. Reducing the amount of power generation increases the amount of unreacted fuel gas consumed in the combustion unit 12. The increase in the amount of fuel gas consumed may cause the temperature detected by the first detection unit 14 to fall within the determined temperature range.

[0025] The control unit 15 may determine a supply amount required of the first supply unit 17, for example, to adjust the temperature of the combustion unit 12 and the amount of power generated by the fuel cell 11. When the supply amount required of the first supply unit 17 is equal to or greater than the first supply amount, the control unit 15 may control the first supply unit 17 to fix the supply amount in the first supply unit 17 to the first supply amount. The first supply amount may be a value set to be less than the maximum supply amount set for the first supply unit 17. More specifically, the control unit 15 may determine a setting value (e.g., rotation speed, current value, etc.) of the first supply unit 17 corresponding to the required supply amount, depending on the type of the first supply unit 17.

[0026] When the supply amount of the first supply unit 17 is fixed to the first supply amount, the control unit 15 may change the power generation amount of the fuel cell 11 when the temperature detected by the first detection unit 14 falls outside the temperature range corresponding to the power generation amount acquired by the acquisition unit 13 in the correspondence relationship.

[0027] The control unit 15 may control the second supply unit 18 to adjust the amount of water supplied to the reformer 16 in accordance with the amount of supply of the variable methane concentration fuel detected by the first detection unit 14. Specifically, the control unit 15 may increase the amount of water supplied to the reformer 16 as the amount of supply of the variable methane concentration fuel detected by the first detection unit 14 increases.

[0028] When the supply amount of the first supply unit 17 is fixed at the first supply amount, the control unit 15 may adjust the amount of water supplied to the reformer 16 so as to vary the first ratio. The first ratio is the ratio of the amount of substance of water supplied to the reformer 16 to the amount of substance of carbon in methane contained in the methane concentration varying fuel. Alternatively, the control unit 15 may adjust the amount of water supplied to the reformer 16 so as to maintain the second ratio constant. The second ratio is the ratio of the amount of substance of water supplied to the reformer 16 to the amount of substance of carbon contained in the methane concentration varying fuel. A value for the second ratio that improves power generation efficiency while suppressing carbon deposition in the fuel cell 11 and the reformer 16 may be calculated in advance and stored as information in the memory unit.

[0029] When the required load on the fuel cell 11 changes, the control unit 15 may change the amount of power generated by the fuel cell 11 and the amount of supply from the first supply unit 17 in stages according to the amount of change in the required load. Specifically, the control unit 15 may control the power adjustment unit 19 and the first supply unit 17 so that the total amount of change in the amount of power generated and the amount of supply according to the amount of change in the required load is divided and changed in multiple increments.

[0030] The control unit 15 may estimate the concentration of methane contained in the variable methane concentration fuel based on the amount of power generation acquired by the acquisition unit 13 and the temperature detected by the first detection unit 14 .

[0031] Specifically, the control unit 15 may estimate the amount of fuel gas (methane) consumed in the fuel cell 11 based on the amount of power generated acquired by the acquisition unit 13. There is a correspondence relationship between the current value of the fuel cell 11 and the amount of combustion gas consumed, and this correspondence relationship may be calculated in advance and stored in the storage unit. The control unit 15 may calculate the amount of fuel gas consumed by reading out the consumption amount corresponding to the current value acquired from the power adjustment unit 19.

[0032] Furthermore, the control unit 15 may estimate the consumption amount of unreacted fuel gas combusted in the combustion unit 12 based on the temperature detected by the first detection unit 14. There is a correspondence relationship between the temperature of the combustion unit 12 and the consumption amount of unreacted fuel gas, and this correspondence relationship may be calculated in advance and stored in the memory unit. The control unit 15 may calculate the consumption amount of unreacted fuel gas by reading out the consumption amount corresponding to the temperature detected by the first detection unit 14.

[0033] Furthermore, the control unit 15 may calculate the methane content in the methane concentration varying fuel by summing the amount of fuel gas consumed in the fuel cell 11 and the amount of unreacted fuel gas burned in the combustion unit 12. Furthermore, the control unit 15 may estimate the methane concentration contained in the methane concentration varying fuel by dividing the calculated methane content by the total supply amount of the methane concentration varying fuel. The control unit 15 may acquire the total supply amount of the methane concentration varying fuel as information from a flow rate sensor. The total supply amount of the methane concentration varying fuel to be supplied may be determined from the estimated methane concentration.

[0034] Next, the supply amount adjustment process executed by the control unit 15 in this embodiment will be described with reference to the flowchart of Fig. 2. The supply amount adjustment process starts, for example, every time a required supply amount is determined.

[0035] In step S100, the control unit 15 determines whether the requested supply amount is equal to or greater than the first supply amount. If it is equal to or greater than the first supply amount, the process proceeds to step S101. If it is not equal to or greater than the first supply amount, the process proceeds to step S102.

[0036] In step S101, the control unit 15 controls the first supply unit 17 to fix the supply amount of the variable methane concentration fuel to the first supply amount. After the first supply unit 17 is controlled, the supply amount adjustment process ends.

[0037] In step S102, the control unit 15 controls the first supply unit 17 so that the supply amount of the variable methane concentration fuel matches the requested supply amount. After the first supply unit 17 has been controlled, the supply amount adjustment process ends.

[0038] Next, the power generation amount adjustment process executed by the control unit 15 in this embodiment will be described with reference to the flowchart of Fig. 3. The power generation amount adjustment process is started, for example, every time a required supply amount is determined.

[0039] In step S200, the control unit 15 determines whether the supply amount of the variable methane concentration fuel is fixed to the first supply amount. If it is fixed, the process proceeds to step S201. If it is not fixed, the process proceeds to step S204.

[0040] In step S201, the control unit 15 determines the temperature range corresponding to the amount of power generation acquired by the acquisition unit 13. After the determination, the process proceeds to step S202.

[0041] In step S202, the control unit 15 determines whether the temperature detected by the first detection unit 14 is below the lower limit of the temperature range determined in step S201. If the temperature is below the lower limit, the process proceeds to step S203. If the temperature is not below the lower limit, the process proceeds to step S204.

[0042] In step S203, the control unit 15 controls the power adjustment unit 19 to reduce the amount of power generated by the fuel cell 11. After the amount of power generated has been reduced, the process proceeds to step S208.

[0043] In step S204, the control unit 15 determines whether the temperature detected by the first detection unit 14 exceeds the upper limit of the temperature range determined in step S201. If the upper limit is exceeded, the process proceeds to step S205. If the upper limit is not exceeded, the process proceeds to step S208.

[0044] In step S205, the control unit 15 determines whether the amount of power generated by the fuel cell 11 is at the upper limit. If it is at the upper limit, the process proceeds to step S206. If it is not at the upper limit, the process proceeds to step S207.

[0045] In step S206, the control unit 15 reduces the amount of fuel gas supplied to the fuel cell 11. After the amount of fuel gas supplied is reduced, the process proceeds to step S208.

[0046] In step S207, the control unit 15 controls the power adjustment unit 19 to increase the amount of power generated by the fuel cell 11. After the amount of power generated has increased, the process proceeds to step S208.

[0047] In step S208, the control unit 15 adjusts the amount of water supplied to the reformer 16 so as to maintain the second ratio constant. After adjusting the amount of water supplied, the power generation amount adjustment process ends.

[0048] The fuel cell device 10 of this embodiment, configured as described above, includes a solid oxide fuel cell 11, a combustion unit 12 that combusts the unreacted fuel gas in the fuel cell 11, an acquisition unit 13 that acquires the amount of power generated by the fuel cell 11, a first detection unit 14 that detects the temperature of the combustion unit 12, and a control unit 15 that controls the amount of power generated by the fuel cell 11 to change if the temperature detected by the first detection unit 14 falls outside a temperature range corresponding to the amount of power generated by the fuel cell 11 and acquired by the acquisition unit 13, which is a predetermined correspondence relationship between the amount of power generated by the fuel cell 11 and the temperature range of the combustion unit. In the fuel cell device 10, hydrocarbons such as methane contained in the raw fuel that forms the basis of the fuel gas are used for power generation in the fuel cell 11 and combustion in the combustion unit 12. Appropriate amounts of hydrocarbons used for power generation in the fuel cell 11 and combustion in the combustion unit 12 can be estimated based on a balance between stable operation and improved power generation efficiency. Therefore, a correspondence relationship between the amount of power generated by the fuel cell 11 and the amount of raw fuel supplied is preset to achieve the estimated appropriate relationship. On the other hand, in a configuration using a raw fuel with a fluctuating hydrocarbon concentration, it is difficult to adjust the temperature within a predetermined range for the desired power generation amount, which can lead to unstable operation of the fuel cell device 10. Unstable operation can easily cause fluctuations in the amount of unreacted fuel gas sent to the combustion section 12. This can make the temperature of the combustion section 12 more likely to change. In response to such an event, the fuel cell device 10 having the above-described configuration can easily adjust the temperature of the combustion section 12 to a temperature appropriate for the power generation amount, because the temperature detected by the first detection section 14 changes the power generation amount of the fuel cell 11 under the above-described conditions. Therefore, the fuel cell device 10 can stabilize its operation.

[0049] The fuel cell device 10 further includes a first supply unit 17 that has a specific maximum supply amount and supplies fuel gas to the fuel cell 11, and the control unit 15 fixes the supply amount of the first supply unit 17 to the first supply amount when the supply amount required of the first supply unit 17 is equal to or greater than the first supply amount, which is set to be less than the maximum supply amount. It may be difficult for the first supply unit 17 to stably adjust the supply amount between the first supply amount and the maximum supply amount. In response to such an event, the fuel cell device 10 having the above-described configuration stabilizes the supply amount of raw fuel by fixing the supply amount at the first supply amount, thereby further stabilizing operation.

[0050] Furthermore, when the supply rate of the first supply unit 17 is fixed to the first supply rate, the fuel cell device 10 changes the amount of power generated by the fuel cell 11 when the temperature detected by the first detection unit 14 falls outside the temperature range corresponding to the amount of power generated acquired by the acquisition unit 13. With this configuration, the fuel cell device 10 changes the amount of power generated while stabilizing the supply rate of the first supply unit 17, thereby further stabilizing operation.

[0051] Furthermore, in the fuel cell device 10, when the required load on the fuel cell 11 changes, the control unit 15 gradually changes the amount of power generated by the fuel cell 11 and the amount of supply from the first supply unit 17 in accordance with the amount of change in the required load. When using a fuel with a variable methane concentration, the methane concentration fluctuates, so if the amount of power generated and the amount of raw fuel supplied are changed all at once toward the adjusted target values, it is difficult to keep the temperature of the combustion unit 12, in particular, within the required temperature range. On the other hand, the fuel cell device 10 having the above-described configuration can stably change the amount of power generated while maintaining the temperature of the combustion unit 12 within the required temperature range. Therefore, the fuel cell device 10 can further stabilize its operation.

[0052] Furthermore, in the fuel cell device 10, the control unit 15 estimates the methane concentration contained in the variable methane concentration fuel based on the amount of power generation acquired by the acquisition unit 13 and the temperature detected by the first detection unit 14. With this configuration, the fuel cell device 10 can acquire information that can contribute to improving the operation of the fuel cell device 10 and the operation of the manufacturing equipment for variable methane concentration fuel, etc.

[0053] Furthermore, in the fuel cell device 10, when the temperature detected by the first detector 14 exceeds the determined temperature range, the control unit 15 controls the fuel cell 11 to increase the amount of power generated. With this configuration, the temperature detected by the first detector 14 can be brought within the determined temperature range, further stabilizing operation.

[0054] Furthermore, in the fuel cell device 10, when the amount of power generated by the fuel cell 11 is at its upper limit, the control unit 15 reduces the amount of fuel gas supplied to the fuel cell 11. With this configuration, the temperature detected by the first detection unit 14 can be kept within the determined temperature range, further stabilizing operation.

[0055] Furthermore, in the fuel cell device 10, the control unit 15 controls the fuel cell 11 to reduce the amount of power generated when the temperature detected by the first detection unit 14 is below the determined temperature range. With this configuration, the temperature detected by the first detection unit 14 can be kept within the determined temperature range, further stabilizing operation.

[0056] In one embodiment, (1) a fuel cell device includes: a solid oxide fuel cell that generates electricity using fuel gas; a combustion unit that combusts the unreacted fuel gas in the fuel cell; an acquisition unit that acquires the amount of electricity generated by the fuel cell; a first detection unit that detects the temperature of the combustion unit; and a control unit that controls the amount of electricity generated by the fuel cell to change if the temperature detected by the first detection unit falls outside a temperature range corresponding to the amount of electricity generated acquired by the acquisition unit in a correspondence relationship between the amount of electricity generated by the fuel cell and the temperature range of the combustion unit that is predetermined.

[0057] (2) The fuel cell device of (1) above further comprises a first supply unit that has a specific maximum supply amount set and supplies fuel gas to the fuel cell, and when the supply amount required of the first supply unit is equal to or greater than a first supply amount set to be less than the maximum supply amount, the control unit fixes the supply amount in the first supply unit to the first supply amount.

[0058] (3) In the fuel cell device of (2) above, when the supply amount of the first supply unit is fixed to the first supply amount, the control unit changes the power generation amount of the fuel cell when the temperature detected by the first detection unit falls outside the temperature range corresponding to the power generation amount acquired by the acquisition unit in the correspondence relationship.

[0059] (4) The fuel cell device of (3) above further includes a reformer that generates the fuel gas by steam reforming a methane concentration varying fuel, and a second supply unit that supplies water to the reformer, wherein the control unit varies a first ratio, which is the ratio of water supplied to the reformer to carbon in methane contained in the methane concentration varying fuel, when the supply amount of the first supply unit is fixed to the first supply amount.

[0060] (5) In the fuel cell device of (2) above, when the required load on the fuel cell changes, the control unit changes the amount of power generated by the fuel cell and the amount of supply by the first supply unit in stages according to the amount of change in the required load.

[0061] (6) In the fuel cell device of (4) above, the control unit estimates the methane concentration contained in the variable methane concentration fuel based on the amount of power generation acquired by the acquisition unit and the temperature detected by the first detection unit.

[0062] (7) In any of the fuel cell devices described in (1) to (6) above, the control unit increases the amount of power generated by the fuel cell when the temperature detected by the first detection unit exceeds the temperature range corresponding to the amount of power generated by the fuel cell and acquired by the acquisition unit in a correspondence relationship between the amount of power generated by the fuel cell and the temperature range of the combustion unit that is predetermined.

[0063] (8) In the fuel cell device of (7) above, the control unit reduces the amount of fuel gas supplied to the fuel cell when the amount of power generated by the fuel cell is at an upper limit value.

[0064] (9) In any of the fuel cell devices described in (1) to (8) above, the control unit reduces the power generation amount of the fuel cell when the temperature detected by the first detection unit is below the temperature range corresponding to the power generation amount acquired by the acquisition unit in a correspondence relationship between the power generation amount of the fuel cell and the temperature range of the combustion unit that is predetermined.

[0065] The above has described an embodiment of the fuel cell device 10, but embodiments of the present disclosure can also be embodied as a method or program for implementing the device, as well as a storage medium on which a program is recorded (for example, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a magnetic tape, a hard disk, or a memory card, etc.).

[0066] Furthermore, the implementation form of the program is not limited to application programs such as object code compiled by a compiler or program code executed by an interpreter, but may also be in the form of a program module incorporated into an operating system. Furthermore, the program may or may not be configured so that all processing is performed solely by the CPU on the control board. The program may also be configured so that part or all of it is executed by another processing unit mounted on an expansion board or expansion unit added to the board as needed.

[0067] The drawings illustrating the embodiments of the present disclosure are schematic, and the dimensional ratios and the like in the drawings do not necessarily correspond to the actual ones.

[0068] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art could make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications or alterations are included in the scope of the present disclosure. For example, the functions included in each component can be rearranged so as not to cause logical inconsistencies, and multiple components can be combined or divided into one.

[0069] All of the features described in this disclosure and / or all steps of all disclosed methods or processes may be combined in any combination except combinations in which these features are mutually exclusive. Furthermore, each feature described in this disclosure may be replaced by an alternative feature serving the same, equivalent, or similar purpose, unless expressly denied. Thus, unless expressly denied, each disclosed feature is only one example of a generic series of identical or equivalent features.

[0070] Furthermore, embodiments of the present disclosure are not limited to the specific configurations of any of the above-described embodiments, but rather extend to any novel feature or combination thereof described herein, or any novel method or process step or combination thereof described herein.

[0071] In this disclosure, descriptions such as "first" and "second" are identifiers for distinguishing the configuration. In this disclosure, configurations distinguished by descriptions such as "first" and "second" can have their numbers exchanged. For example, a first supply unit can exchange the identifiers "first" and "second" with a second supply unit. The exchange of identifiers is performed simultaneously. The configurations remain distinguished even after the identifier exchange. Identifiers may be deleted. A configuration from which an identifier has been deleted is distinguished by a symbol. The descriptions of identifiers such as "first" and "second" in this disclosure should not be used solely to interpret the order of the configurations or to justify the existence of an identifier with a smaller number.

[0072] REFERENCE SIGNS LIST 10 fuel cell device 11 fuel cell 12 combustion unit 13 acquisition unit 14 first detection unit 15 control unit 16 reformer 17 first supply unit 18 second supply unit 19 power adjustment unit

Claims

1. A fuel cell device comprising: a solid oxide fuel cell that generates electricity using fuel gas; a combustion unit that combusts the unreacted fuel gas in the fuel cell; an acquisition unit that acquires the amount of electricity generated by the fuel cell; a first detection unit that detects the temperature of the combustion unit; and a control unit that controls the fuel cell to change the amount of electricity generated when the temperature detected by the first detection unit falls outside a temperature range corresponding to the amount of electricity generated acquired by the acquisition unit in a correspondence relationship between the amount of electricity generated by the fuel cell and the temperature range of the combustion unit that is predetermined.

2. A fuel cell device according to claim 1, further comprising a first supply unit which has a specific maximum supply amount set and supplies fuel gas to the fuel cell, wherein the control unit fixes the supply amount in the first supply unit to the first supply amount when the supply amount required of the first supply unit is equal to or greater than a first supply amount set to be less than the maximum supply amount.

3. A fuel cell device according to claim 2, wherein the control unit changes the amount of power generated by the fuel cell when the supply amount of the first supply unit is fixed to the first supply amount and the temperature detected by the first detection unit falls outside the temperature range corresponding to the amount of power generated acquired by the acquisition unit in the correspondence relationship.

4. A fuel cell device according to claim 3, further comprising: a reformer that generates the fuel gas by steam reforming a methane concentration varying fuel; and a second supply unit that supplies water to the reformer, wherein the control unit varies a first ratio, which is the ratio of water supplied to the reformer to carbon in methane contained in the methane concentration varying fuel, when the supply amount of the first supply unit is fixed to the first supply amount.

5. A fuel cell device according to claim 2, wherein when the required load on the fuel cell changes, the control unit changes the amount of power generated by the fuel cell and the amount of supply by the first supply unit in stages according to the amount of change in the required load.

6. A fuel cell device according to claim 4, wherein the control unit estimates the methane concentration contained in the variable methane concentration fuel based on the amount of power generation acquired by the acquisition unit and the temperature detected by the first detection unit.

7. A fuel cell device according to any one of claims 1 to 6, wherein the control unit increases the amount of power generated by the fuel cell when the temperature detected by the first detection unit exceeds the temperature range corresponding to the amount of power generated by the fuel cell and acquired by the acquisition unit in a correspondence relationship between the amount of power generated by the fuel cell and the temperature range of the combustion unit that is predetermined.

8. A fuel cell device according to claim 7, wherein the control unit reduces the amount of fuel gas supplied to the fuel cell when the amount of power generated by the fuel cell is at an upper limit value.

9. A fuel cell device according to any one of claims 1 to 8, wherein the control unit reduces the amount of power generated by the fuel cell when the temperature detected by the first detection unit falls below a temperature range corresponding to the amount of power generated by the fuel cell and acquired by the acquisition unit in a correspondence relationship between the amount of power generated by the fuel cell and the temperature range of the combustion unit that is predetermined.

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