JP2018163767A - Power generator, fuel cell controller and fuel cell control program - Google Patents

Abstract

A power generation device, a fuel cell control device, and a fuel cell control program for improving power generation efficiency are provided. A power generation apparatus includes a fuel cell and a control unit that controls a temperature in the vicinity of the fuel cell. The control unit is arranged in the vicinity of the fuel cell in accordance with an operation time of the fuel cell. The temperature is controlled so that the temperature increase in the vicinity of the fuel cell 20 is larger in the time segment in the initial operation of the fuel cell 20 than in the time segment next to the time segment in the initial operation. [Selection] Figure 1

Description

  The present disclosure relates to a power generation device, a fuel cell control device, and a fuel cell control program. More specifically, the present disclosure relates to a power generation device including a fuel cell, a fuel cell control device, and a fuel cell control program executed by such a device.

  For example, in a power generation system including a fuel cell such as a solid oxide fuel cell (hereinafter referred to as SOFC), a temperature at which a cell stack of a fuel cell module generates power is generally controlled. . For example, the temperature in the vicinity of the cell stack, for example, may be controlled so that the temperature when the cell stack of the fuel cell module generates power is kept constant. Further, for example, Patent Document 1 proposes that the limit temperature of operation of the fuel cell is set higher as the cumulative operation time of the fuel cell becomes longer, and temperature control is performed so as not to exceed this limit temperature. Yes.

JP 2010-114000 A

  For example, in a fuel cell such as SOFC, the operating temperature at the time of power generation affects the power generation efficiency. For this reason, in a power generation system including a fuel cell, it is desirable to appropriately control the operating temperature to increase power generation efficiency.

  An object of the present disclosure is to provide a power generation device, a fuel cell control device, and a fuel cell control program that increase power generation efficiency.

A power generation device according to a first aspect of the present disclosure includes a fuel cell and a control unit that controls a temperature in the vicinity of the fuel cell.
The control unit controls the temperature in the vicinity of the fuel cell according to the operation time of the fuel cell. Further, the control unit performs control so that the temperature increase in the vicinity of the fuel cell is greater in the time segment in the initial operation period of the fuel cell than in the time segment next to the time segment in the initial operation period.

The fuel cell control device according to the second aspect of the present disclosure controls the temperature in the vicinity of the fuel cell according to the operating time of the fuel cell.
The control device performs control so that the temperature increase in the vicinity of the fuel cell is larger in the time segment in the initial operation period of the fuel cell than in the time segment next to the time segment in the initial operation period.

A control program for a fuel cell according to a third aspect of the present disclosure causes a control device that controls the fuel cell to execute a step of controlling the temperature in the vicinity of the fuel cell according to the operating time of the fuel cell.
In addition, the control program causes the control device to increase the temperature in the vicinity of the fuel cell in a time segment in the initial operation period of the fuel cell more than in a time segment next to the time segment in the initial operation period. The control step is executed.

  According to the present disclosure, it is possible to provide a power generation device, a fuel cell control device, and a fuel cell control program that increase power generation efficiency.

It is a functional block diagram showing roughly the composition of the power generator concerning the embodiment of this indication. 6 is a flowchart illustrating an operation of the power generation device according to the embodiment of the present disclosure. It is a figure explaining the example of the target temperature which concerns on embodiment of this indication. 14 is a flowchart illustrating another operation of the power generation device according to the embodiment of the present disclosure. It is a figure explaining other examples of target temperature concerning an embodiment of this indication. FIG. 10 is a functional block diagram schematically showing a modification of the configuration of the power generation device according to the embodiment of the present disclosure.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. First, a configuration of a power generation device according to an embodiment of the present disclosure will be described.

  FIG. 1 is a functional block diagram schematically illustrating a configuration of a power generation device according to an embodiment of the present disclosure.

  As shown in FIG. 1, the power generation device 1 according to an embodiment of the present disclosure is connected to a hot water storage tank 60, a load 100, and a commercial power supply (grid) 200. As shown in FIG. 1, the power generation apparatus 1 generates power by supplying gas and air from the outside, and supplies the generated power to a load 100 and the like.

  As shown in FIG. 1, the power generation apparatus 1 includes a control unit 10, a storage unit 12, a fuel cell module 20, a supply unit 30, an inverter 40, an exhaust heat recovery processing unit 50, and a circulating water processing unit 52. And comprising.

  The power generator 1 includes at least one processor as the controller 10 to provide control and processing capabilities for performing various functions, as will be described in further detail below. According to various embodiments, at least one processor may be implemented as a single integrated circuit (IC) or as a plurality of communicatively connected integrated circuits ICs and / or discrete circuits. Good. The at least one processor can be implemented according to various known techniques.

  In certain embodiments, the processor includes one or more circuits or units configured to perform one or more data computation procedures or processes. For example, a processor may be one or more processors, controllers, microprocessors, microcontrollers, application specific integrated circuits (ASICs), digital signal processors, programmable logic devices, field programmable gate arrays, or any of these devices or configurations The functions described below may be performed by including combinations or combinations of other known devices or configurations.

  The control unit 10 is connected to the storage unit 12, the fuel cell module 20, and the supply unit 30, and controls and manages the entire power generation apparatus 1 including these functional units. The control unit 10 obtains a program stored in the storage unit 12 and executes this program, thereby realizing various functions related to each unit of the power generation device 1. When transmitting a control signal or various types of information from the control unit 10 to other functional units, the control unit and the other functional units may be connected by wire or wirelessly. Control characteristic of this embodiment performed by the control unit 10 will be further described later. Moreover, in this embodiment, the control part 10 shall measure predetermined time, such as measuring the operation time (for example, power generation time) of the cell stack 24. FIG.

  The storage unit 12 stores information acquired from the control unit 10. The storage unit 12 stores a program executed by the control unit 10. In addition, the memory | storage part 12 memorize | stores various data, such as a calculation result by the control part 10, for example. Further, the storage unit 12 will be described below as including a work memory when the control unit 10 operates. The storage unit 12 can be configured by, for example, a semiconductor memory or a magnetic disk, but is not limited thereto, and can be any storage device. For example, the storage unit 12 may be an optical storage device such as an optical disk or a magneto-optical disk.

  The fuel cell module 20 includes a reformer 22 and a cell stack 24. The cell stack 24 of the fuel cell module 20 generates power using gas (fuel gas) supplied from the supply unit 30 and outputs the generated DC power to the inverter 40. The fuel cell module 20 is also called a hot module. In the fuel cell module 20, the cell stack 24 generates heat with power generation. In the present disclosure, the cell stack 24 that actually generates power is appropriately referred to as a “fuel cell”. In the present disclosure, any functional unit including the cell stack 24 may be collectively referred to as “fuel cell” as appropriate. For example, as the “fuel cell”, a single cell, a fuel cell module, or the like can be given.

  The reformer 22 generates hydrogen and / or carbon monoxide using the gas and reformed water supplied from the supply unit 30. The cell stack 24 generates electricity by reacting hydrogen and / or carbon monoxide generated in the reformer 22 with oxygen in the air. That is, in the present embodiment, the cell stack 24 of the fuel cell generates power by an electrochemical reaction. As the reformer, the reformer that performs the above-described steam reforming is illustrated, but as another reformer, partial oxidation reforming (partial reforming) that generates hydrogen using air containing oxygen or the like. A reformer or the like that performs Oxidation (POX) may be used.

  Hereinafter, the cell stack 24 will be described as an SOFC (solid oxide fuel cell). However, the cell stack 24 according to the present embodiment is not limited to the SOFC. The cell stack 24 according to the present embodiment includes, for example, a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), and a molten carbonate fuel cell (PAFC). A fuel cell such as Molten Carbonate Fuel Cell (MCFC) may be used. In the present embodiment, the cell stack 24 may include, for example, four cells that can generate about 700 W of power alone. In this case, the fuel cell module 20 can output about 3 kW of electric power as a whole. However, the cell stack 24 and the fuel cell module 20 according to the present embodiment are not limited to such a configuration, and various configurations can be adopted. For example, the fuel cell module 20 according to the present embodiment may include only one cell stack 24. In this embodiment, the electric power generating apparatus 1 should just be provided with the fuel cell which produces electric power using gas. Therefore, for example, the power generation device 1 can be assumed to have only one fuel cell instead of the cell stack 24 as a fuel cell. Further, the fuel cell according to the present embodiment may be a fuel cell without a module such as PEFC.

  The supply unit 30 includes a gas supply unit 32, an air supply unit 34, and a reforming water supply unit 36. That is, the supply unit 30 supplies gas, air, and reformed water to the cell stack 24.

  The gas supply unit 32 supplies gas to the cell stack 24. At this time, the gas supply unit 32 controls the amount of gas supplied to the cell stack 24 based on a control signal from the control unit 10. In this embodiment, the gas supply part 32 can be comprised by a gas line, for example. Moreover, the gas supply part 32 may perform the desulfurization process of gas, and may heat gas preliminarily. The exhaust heat of the cell stack 24 may be used as a heat source for heating the gas. The gas is, for example, city gas or LPG, but is not limited thereto. For example, the gas may be natural gas or coal gas depending on the fuel cell. In the present embodiment, the gas supply unit 32 supplies a fuel gas used for an electrochemical reaction when the cell stack 24 generates power.

  The air supply unit 34 supplies air to the cell stack 24. At this time, the air supply unit 34 controls the amount of air supplied to the cell stack 24 based on a control signal from the control unit 10. In this embodiment, the air supply part 34 can be comprised by an air line, for example. The air supply unit 34 may preliminarily heat the air taken from the outside and supply the air to the cell stack 24. The exhaust heat of the cell stack 24 may be used as a heat source for heating the air. In the present embodiment, the air supply unit 34 supplies air used for an electrochemical reaction when the cell stack 24 generates power.

  The reforming water supply unit 36 generates steam and supplies it to the cell stack 24. At this time, the reforming water supply unit 36 controls the amount of water vapor supplied to the cell stack 24 based on a control signal from the control unit 10. In the present embodiment, the reforming water supply unit 36 can be configured by, for example, a reforming water line. The reforming water supply unit 36 may generate water vapor using water recovered from the exhaust gas of the cell stack 24 as a raw material. The exhaust heat of the cell stack 24 may be used as a heat source for generating water vapor.

  The inverter 40 is connected to the fuel cell module 20. The inverter 40 converts the DC power generated by the cell stack 24 into AC power. The DC power output from the inverter 40 is supplied to the load 100 via a distribution board or the like. The load 100 receives the power output from the inverter 40 via a distribution board or the like. In FIG. 1, the load 100 is illustrated as a single member, but can be an arbitrary number of various electrical devices constituting the load. The load 100 can also receive power from the commercial power supply 200 via a distribution board or the like. In FIG. 1, the connection between the inverter 40 and the control unit 10 is not shown, but the inverter 40 and the control unit 10 may be connected. With this connection, the control unit 10 can control the output of AC power by the inverter 40.

  The exhaust heat recovery processing unit 50 recovers exhaust heat from the exhaust generated by the power generation of the cell stack 24. The exhaust heat recovery processing unit 50 can be configured with, for example, a heat exchanger. The exhaust heat recovery processing unit 50 is connected to the circulating water processing unit 52 and the hot water storage tank 60.

  The circulating water processing unit 52 circulates water from the hot water storage tank 60 to the exhaust heat recovery processing unit 50. The water supplied to the exhaust heat recovery processing unit 50 is heated by the heat recovered by the exhaust heat recovery processing unit 50 and returns to the hot water storage tank 60. The exhaust heat recovery processing unit 50 exhausts the exhaust from which the exhaust heat has been recovered to the outside. Further, as described above, the heat recovered by the exhaust heat recovery processing unit 50 can be used for heating gas, air, or reformed water.

  The hot water storage tank 60 is connected to the exhaust heat recovery processing unit 50 and the circulating water processing unit 52. The hot water storage tank 60 can store hot water generated using the exhaust heat recovered from the cell stack 24 of the fuel cell module 20 or the like.

  As illustrated in FIG. 1, the power generation device 1 includes a current sensor 70 that detects a current generated by the cell stack 24. As shown in FIG. 1, the current sensor 70 can be installed at a position for detecting a direct current output from the fuel cell module 20 toward the inverter 40. However, the current sensor 70 may be installed at other positions as long as the current generated by the cell stack 24 can be detected. The current sensor 70 can be configured by, for example, a CT (Current Transformer). However, the current sensor 70 is not limited to CT, and any member can be employed as long as it is a member that can measure current. For example, the current sensor 70 may be based on a principle such as a Hall element method, a Rogowski method, or a zero flux method. The current sensor 70 is connected to the control unit 10. The current sensor 70 transmits a signal based on the detected current to the control unit 10. By receiving this signal, the control unit 10 can grasp the current generated by the cell stack 24.

  In the present embodiment, the control unit 10 controls the temperature of the cell stack 24. In the present embodiment, the control unit 10 may control the temperature of the entire system of the fuel cell module 20 including the reformer 22 and the cell stack 24. Such power control of the cell stack 24 can change the power generation efficiency of the cell stack 24. The temperature control of the cell stack 24 by the control unit 10 will be further described later.

  As shown in FIG. 1, the power generation device 1 includes a temperature sensor 80 that detects the temperature in the vicinity of the cell stack 24. As shown in FIG. 1, the temperature sensor 80 can be installed at a position for detecting the temperature in the vicinity of the cell stack 24. Here, the vicinity of the cell stack 24 where the temperature sensor 80 detects the temperature is a position suitable for measuring a temperature serving as a reference for controlling the temperature of the cell stack 24 in the power generation apparatus 1, for example, the cell stack 24 is generated. It can be a position where heat is conducted appropriately. In the present embodiment, the vicinity of the cell stack 24 where the temperature sensor 80 detects the temperature may be a position where the cell stack 24 itself exists. Further, the vicinity of the cell stack 24 where the temperature sensor 80 detects the temperature may be, for example, the entire cell stack 24 or a part of the cell stack 24 (for example, a cell).

  The temperature sensor 80 can be constituted by, for example, a thermocouple. In this case, for example, a thermocouple may be inserted into an introduction plate that introduces air into the cell stack 24. On the other hand, the temperature sensor 80 is assumed to be unable to measure excessively high heat depending on the material constituting the temperature sensor 80. In such a case, the temperature sensor 80 is separated from the cell stack 24, for example, but may detect the temperature at a position where the heat generated by the cell stack 24 is conducted. When the temperature sensor 80 is away from the cell stack 24, the vicinity of the cell stack 24 where the temperature sensor 80 detects the temperature may be located, for example, in the combustion section above the cell stack 24. Further, when the temperature sensor 80 is away from the cell stack 24, the temperature near the cell stack 24 where the temperature sensor 80 detects the temperature is sufficiently high even if the temperature sensor 80 is slightly away from above the combustion part. Any position that can be measured is acceptable.

  The temperature sensor 80 is not limited to a thermocouple, and any member can be adopted as long as it is a member capable of measuring temperature. For example, the temperature sensor 80 may be a thermistor or a platinum resistance temperature detector. The temperature sensor 80 is connected to the control unit 10. The temperature sensor 80 transmits a signal based on the detected temperature to the control unit 10. By receiving this signal, the control unit 10 can grasp the temperature near the cell stack 24.

  The temperature sensor 80 is not limited to a configuration in which only one temperature sensor 80 is installed as shown in FIG. For example, when the fuel cell module 20 includes four cell stacks 24, the temperature sensor 80 may be installed in each cell stack 24. In this case, the control unit 10 may grasp the temperature of each cell stack 24 individually or may grasp the average of the temperatures of the four cell stacks 24.

  Next, operation | movement of the electric power generating apparatus 1 which concerns on embodiment of this indication is demonstrated.

  In the present embodiment, the power generation device 1 controls the temperature in the vicinity of the cell stack 24 according to the accumulated power generation time of the cell stack 24. Here, the vicinity of the cell stack 24 where the power generation device 1 controls the temperature is a position suitable for controlling the temperature of the cell stack 24 in the power generation device 1, for example, a position where the temperature sensor 80 described above detects the temperature. be able to. Moreover, when an example as a fuel cell is a single cell, the vicinity of the single cell in which the power generation device 1 controls the temperature can be a position where heat generated by the single cell is appropriately conducted. For example, it may be a position where the single cell itself exists, or may be the entire single cell or a part of the single cell. Further, when the temperature cannot be measured because the unit cell becomes excessively hot, the vicinity of the unit cell where the power generation device 1 controls the temperature is, for example, a position where the heat generated by the unit cell is conducted away from the unit cell. It may be. When an example of the fuel cell is the cell stack 24, the vicinity of the cell stack 24 where the power generation device 1 controls the temperature can be a position where the heat generated by the cell stack 24 is appropriately conducted. For example, it may be a position where the cell stack 24 itself exists, or may be a position in the vicinity of where the entire cell stack 24 or any cell in the cell stack 24 exists.

  As described above, the operating temperature at which the cell stack 24 generates power affects the power generation efficiency of the cell stack 24. In particular, at the initial stage when the cell stack 24 starts power generation, the initial deterioration of the cell stack 24 occurs. Therefore, unless the operating temperature when the cell stack 24 generates power is appropriately controlled, the power generation efficiency is not sufficiently high. For this reason, in this embodiment, in order to increase the power generation efficiency of the cell stack 24, the operating temperature when the cell stack 24 generates power is controlled. Hereinafter, operation | movement of the electric power generating apparatus 1 is demonstrated in detail.

  FIG. 2 is a flowchart showing the operation of the power generation device 1 according to this embodiment.

  First, target temperature calculation processing in the present embodiment will be described. In the present embodiment, the control unit 10 of the power generation apparatus 1 calculates a target temperature for performing temperature control of the cell stack 24 according to the current generated by the cell stack 24 and the time from the start of the cell stack 24. .

  The operation shown in FIG. 2 can be started when the power generation device 1 starts power generation, that is, when the cell stack 24 starts power generation. When the operation shown in FIG. 2 starts, the control unit 10 controls the cell stack 24 to start power generation (step S11). In step S11, the control unit 10 controls the reformer 22, the supply unit 30, and the like so that the cell stack 24 starts power generation. Thus, since the operation | movement which the cell stack 24 starts electric power generation can be performed similarly to control of a general fuel cell, more detailed description is abbreviate | omitted.

  When the cell stack 24 starts power generation in step S11, the control unit 10 acquires the current value of the direct current detected by the current sensor 70 (step S12).

  When the current value is acquired in step S12, the control unit 10 acquires the accumulated power generation time of the cell stack 24 (step S13). In order to obtain the accumulated power generation time of the cell stack 24 in step S13, the control unit 10 detects the power generation time after the cell stack 24 starts power generation at a predetermined timing. In the present embodiment, the power generation time of the cell stack 24 is not strictly limited to the time during which the cell stack 24 is generating power. For example, instead of the time when the cell stack 24 is generating power, the time when the fuel cell module 20 is operating or the time when the fuel cell is generating power may be used. In the present disclosure, what is acquired in step S13 can be collectively referred to as “accumulated operating time of the fuel cell”. Specifically, in the present embodiment, the operation time of the fuel cell can be the power generation time during which the cell stack 24 generates power. The power generation time can be a time counted when the temperature of the cell stack 24 or the like becomes equal to or higher than a predetermined temperature. The power generation time can be a time counted when, for example, the current (or power) generated by the cell stack 24 exceeds a predetermined value.

  Further, in the present embodiment, the accumulated power generation time of the cell stack 24 is not limited to a value obtained by integrating only the time during which power is output from the cell stack 24. For example, when the fuel cell continues to operate for a predetermined period, the fuel cell may stop power generation for the purpose of normally operating the safety function. Therefore, in the present embodiment, the accumulated power generation time may include, for example, the time when such power generation is stopped, or may exclude the time when such power generation is stopped. Good.

  The control unit 10 can store the power generation time of the cell stack 24 detected in this way in the storage unit 12. In this case, the control unit 10 can acquire the accumulated power generation time of the cell stack 24 from the storage unit 12. For example, the cell stack 24 may include a mechanism for accumulating and recording the power generation time. In this case, the control unit 10 can directly acquire the accumulated power generation time from the cell stack 24.

  When the integrated power generation time is acquired in step S13, the control unit 10 calculates a target temperature corresponding to the current value acquired in step S12 and the integrated power generation time acquired in step S13 (step S14). Here, the target temperature is a temperature aimed at reaching when the temperature control of the cell stack 24 is performed. A specific example of the temperature control of the cell stack 24 performed toward the target temperature will be described later.

  In order to calculate the target temperature in step S14, the power generation apparatus 1 sets a target temperature corresponding to the current value generated by the cell stack 24 and the accumulated power generation time of the cell stack 24, and stores the target temperature in the storage unit 12. Remember. Here, the power generation device 1 uses a target temperature corresponding to the current value of the current generated by the cell stack 24 and the accumulated power generation time of the cell stack 24 as a correspondence table such as a lookup table (LUT). It can be stored in the storage unit 12. Further, the power generation apparatus 1 may store the calculation formula for the target temperature in the storage unit 12 as a function of the accumulated power generation time of the cell stack 24 according to the current value of the current generated by the cell stack 24. . Further, the power generation apparatus 1 may store the target temperature for some typical integrated power generation times in the storage unit 12 according to the current value of the current generated by the cell stack 24. In this case, the control unit 10 reads the target temperature of the representative accumulated power generation time closest to the current accumulated power generation time of the cell stack 24 and corrects the read target temperature in consideration of the actual accumulated power generation time. Also good.

  FIG. 3 is a diagram illustrating a specific example of the target temperature calculated in step S14. Hereinafter, the target temperature in the present embodiment will be further described.

  FIG. 3 is a graph showing an example of the target temperature corresponding to the accumulated power generation time of the cell stack 24 for several representative current values of the current generated by the cell stack 24. The horizontal axis of the graph shown in FIG. 3 indicates the accumulated power generation time of the cell stack 24. Further, the vertical axis of the graph shown in FIG. 3 indicates the target temperature of the cell stack 24.

  In FIG. 3, some typical current values of the current generated by the cell stack 24 are as follows: 0 [A], 5 [A], and rated output (about 11 [A]). The target temperature according to the accumulated power generation time is shown. In FIG. 3, the graph of the target temperature when the current value is 0 [A] is indicated by a fine broken line. Further, the graph of the target temperature when the current value is 5 [A] is indicated by a rough broken line. Further, the graph of the target temperature when the current value is rated (about 11 [A]) is indicated by a solid line.

  As shown in FIG. 3, in the present embodiment, the magnitude of the target temperature rise is set differently according to the accumulated power generation time of the cell stack 24. In the example shown in FIG. 3, the accumulated power generation time of the cell stack 24 is divided into three time segments so that the magnitude of the increase in target temperature is different in each time segment. In the following description, the time section in which the accumulated power generation time of the cell stack 24 is 0 to 5000 hours is referred to as “first section”. In addition, a time section in which the accumulated power generation time of the cell stack 24 is 5000 to 30000 hours is referred to as a “second section”. In addition, a time section in which the accumulated power generation time of the cell stack 24 is 30000 hours or later is referred to as a “third section”.

In the example shown in FIG. 3, when the current generated by the cell stack 24 is 0 [A], the target temperature is set as follows in each time segment.
First division: rise from 640 ° C to 645 ° C Second division: rise from 645 ° C to 650 ° C Third division: keep at 650 ° C

Similarly, in the example shown in FIG. 3, when the current generated by the cell stack 24 is 5 [A], the target temperature is set as follows in each time segment.
First division: rising from 655 ° C to 665 ° C Second division: rising from 665 ° C to 675 ° C Third division: keeping at 675 ° C

Similarly, in the example shown in FIG. 3, when the current generated by the cell stack 24 is rated (about 11 [A]), the target temperature is set as follows in each time segment.
First division: rise from 670 ° C to 685 ° C Second division: rise from 685 ° C to 700 ° C Third division: keep at 700 ° C

  In the example shown in FIG. 3, for any current value, for example, the target temperature increase (for example, the rate of temperature increase) of the cell stack 24 at a predetermined time is larger in the first section than in the second section. It has become. As described above, in the initial stage when the cell stack 24 starts power generation, the initial deterioration of the cell stack 24 occurs. For this reason, in the initial time division (first division) when the cell stack 24 starts generating power, the target temperature of the cell stack 24 increases more than in the next time division (second division). Set as follows. By controlling the temperature in the vicinity of the cell stack 24 according to such settings, the power generation efficiency of the cell stack 24 can be increased. Therefore, the initial time section (first section) at which the cell stack 24 starts power generation is the initial time section (for example, accumulated power generation time 0 to 5000 hours) at which power generation is likely to occur in the cell stack 24. It is preferable to do this. Further, it is desirable that the magnitude of the increase in the target temperature of the cell stack 24 is appropriately set so as to increase the power generation efficiency in consideration of various factors such as the characteristics of the cell stack 24. For example, the magnitude at which the target temperature increases can be appropriately set based on the result of a test for operating (power generation) the same type of cell stack as the cell stack 24.

  FIG. 3 shows an example in which the current value generated by the cell stack 24 is 0 [A], 5 [A], and the rated output. As for the current values other than those described above, the power generation device 1 may set the target temperature in each time segment and store it in the storage unit 12 as in the example shown in FIG. In this case, for each current value, each target temperature value may be stored in the storage unit 12. Further, the calculation formula for the target temperature in each section may be stored as a function for each current value. Further, target temperature values for several current values as in the example shown in FIG. 3 may be used after correcting for each current value. Further, the target temperature for the current value or the accumulated power generation time not shown in FIG. 3 may be calculated by, for example, linear interpolation processing.

  When the fuel cell module 20 includes a plurality of cell stacks 24, the target temperature calculated in step S14 may be different according to each cell stack, or may be the same for all cell stacks. When the fuel cell module 20 includes a plurality of cell stacks 24 such as four, for example, the control unit 10 may calculate a target temperature of the plurality of cell stacks 24 measured as having the highest temperature. In this case, in consideration of temperature unevenness in the cell stack 24, the target temperature in the cell stack 24 (for example, the center of the cell stack 24) may be lowered when the load is small.

  After calculating the target temperature in step S14, the control unit 10 determines whether or not an instruction to end the power generation of the cell stack 24 has been given (step S15). When an instruction to end power generation is given in step S15, the control unit S15 ends the power generation of the cell stack 24 and ends the operation shown in FIG. On the other hand, if the power generation end instruction is not given in step S15, the control unit S15 returns to step S11 and continues the process.

  Thus, in the present embodiment, the control unit 10 sets the target temperature based on the power generation time of the cell stack 24 and the current generated by the cell stack 24. Here, the control unit 10 can set the target temperature based on the current generated by the cell stack 24 detected by the current sensor 70. By referring to such a target temperature, the control unit 10 controls the temperature near the cell stack 24. In addition, when the current generated by the cell stack 24 is constant, the control unit 10 performs the next time division (second division) in the initial time division (first division) when the cell stack 24 starts power generation. Rather, it is preferable to set the target temperature so as to increase significantly.

  For example, when the power generation device 1 generates power following the power consumption of the load 100, the power generated by the cell stack 24 can change frequently. In such a case, the target temperature can also change frequently. For this reason, the control unit 10 may perform the target temperature calculation operation shown in FIG. 2 at a relatively high frequency cycle such as every several milliseconds.

  Next, the temperature control operation in the present embodiment will be described. In the power generation apparatus 1, after calculating the target temperature as described above, the control unit 10 controls the temperature near the cell stack 24 to be close to the calculated target temperature.

  FIG. 4 is a flowchart showing the operation of the power generation device 1 according to this embodiment.

  It is assumed that the target temperature of the cell stack 24 has been calculated as described in FIGS. 2 and 3 at the time when the operation of FIG. 4 starts. When the operation shown in FIG. 4 starts, first, the control unit 10 acquires the temperature near the cell stack 24 (step S21). In step S21, the control unit 10 can acquire the temperature detected by the temperature sensor 80.

  If the temperature near the cell stack 24 is acquired in step S21, the control unit 10 determines whether or not the temperature acquired in step S21 is higher than the target temperature calculated in step S14 of FIG. 2 (step S22).

  In step S22, when it is determined that the acquired temperature is higher than the target temperature, the control unit 10 desirably lowers the temperature in the vicinity of the cell stack 24. Therefore, in this case, the control unit 10 decreases the air utilization rate of the air supplied to the cell stack 24 (step S23). Here, the air utilization rate is the proportion of the air actually used for power generation out of the air supplied to the cell stack 24. In general, the amount of air actually used for power generation in the cell stack 24 does not change very rapidly. For this reason, decreasing the air utilization rate in the cell stack 24 means that the total amount of air supplied to the cell stack 24 is increased. As the total amount of air supplied to the cell stack 24 increases, excess air increases, and the temperature in the vicinity of the cell stack 24 decreases. Thus, in step S23, the control unit 10 can control the temperature in the vicinity of the cell stack 24 by adjusting the air supplied from the air supply unit 34 to the cell stack 24.

  In step S22, in order to lower the temperature near the cell stack 24, the control unit 10 may decrease the amount of inflow of gas supplied to the cell stack 24 (step S23). When the inflow amount of the gas (fuel gas) supplied to the cell stack 24 decreases, combustion in the cell stack 24 is suppressed, so that the temperature in the vicinity of the cell stack 24 decreases. Thus, in step S23, the control unit 10 may control the temperature in the vicinity of the cell stack 24 by adjusting the gas supplied by the gas supply unit 32. In this case, it is desirable to perform temperature control in consideration of the possibility of misfire if the amount of inflow of gas supplied to the cell stack 24 decreases excessively.

  If the process for lowering the temperature near the cell stack 24 is performed in step S23, the control unit 10 returns to step S21 and continues the operation.

  On the other hand, when it is determined in step S22 that the acquired temperature is not higher than the target temperature, the control unit 10 determines whether or not the temperature acquired in step S21 is lower than the target temperature calculated in step S14 of FIG. (Step S24).

  In step S24, when it is determined that the acquired temperature is lower than the target temperature, the control unit 10 desirably increases the temperature in the vicinity of the cell stack 24. Therefore, in this case, contrary to step S23, the control unit 10 increases the air utilization rate of the air supplied to the cell stack 24 (step S25). Here, the increase in the air utilization rate in the cell stack 24 means that the total amount of air supplied to the cell stack 24 is reduced, contrary to step S23. When the total amount of air supplied to the cell stack 24 decreases, excess air decreases, and the temperature in the vicinity of the cell stack 24 increases. In step S24, the controller 10 may increase the inflow amount of gas supplied to the cell stack 24 in order to increase the temperature in the vicinity of the cell stack 24 (step S25).

  If the process for raising the temperature of the cell stack 24 vicinity is performed in step S25, the control part 10 will return to step S21 and will continue operation | movement. Moreover, also when it determines with the acquired temperature not being lower than target temperature in step S24, the control part 10 returns to step S21 and continues operation | movement.

  It has been described that the target temperature calculation operation shown in FIG. 2 may be performed in a relatively high frequency cycle such as every several milliseconds. On the other hand, it is difficult to rapidly change the temperature in the vicinity of the cell stack 24 accompanying the temperature control operation described in FIG. For this reason, the control unit 10 may change the operation of the temperature control illustrated in FIG. 4 relatively gently, for example, about 1 ° C. per minute.

  Further, it is desirable that the target temperature calculation operation described with reference to FIG. 2 and the temperature control operation described with reference to FIG. However, depending on the performance of the control unit 10, for example, the temperature control operation described in FIG. 4 may be interrupted at a predetermined interval while the target temperature calculation operation shown in FIG.

  Thus, in the present embodiment, the control unit 10 calculates the temperature near the cell stack 24 based on the target temperature calculated in step S14 in FIG. 2 and the temperature detected by the temperature sensor 80 in step S21 in FIG. Control. That is, in the present embodiment, the control unit 10 controls the temperature in the vicinity of the cell stack 24 toward the target temperature calculated in step S14 in FIG. Therefore, the control unit 10 controls the temperature in the vicinity of the cell stack 24 according to the power generation time of the cell stack 24. Further, the control unit 10 performs control so that the temperature increase in the vicinity of the cell stack 24 is larger in the first section than in the second section. Here, the first division is preferably set based on the influence of the initial deterioration of the cell stack 24.

  As described above, according to the power generation device 1 according to the present embodiment, the power generation efficiency can be increased.

  Next, another specific example of the target temperature calculated in step S14 of FIG. 2 will be described.

  FIG. 5 is a graph showing examples of target temperatures corresponding to the accumulated power generation time of the cell stack 24 for several typical current values of the current generated by the cell stack 24, as in FIG. Yes. Hereinafter, descriptions similar to those in FIG. 3 are simplified or omitted as appropriate.

  In the example described with reference to FIG. 3, in consideration of the initial deterioration of the cell stack 24, the target temperature of the cell stack 24 is set to be larger in the first section than in the second section. On the other hand, some fuel cells, such as SOFC, have a lifetime of about 90,000 hours of accumulated power generation. In such a fuel cell, the cell stack 24 tends to progress more rapidly as it approaches the end of the power generation possible time. For this reason, it is preferable to set the target temperature of the cell stack 24 to be higher in the time section near the end of the time during which the cell stack 24 can generate power than in the previous time section. By controlling the temperature in the vicinity of the cell stack 24 according to such a setting, the power generation efficiency of the cell stack 24 that is approaching the end of the power generation possible time can be increased.

  FIG. 5 shows an example of the target temperature corresponding to the accumulated power generation time longer than that in FIG. In the example shown in FIG. 5, the accumulated power generation time of the cell stack 24 is divided into four time segments, and the magnitude of the target temperature increase is set for each time segment. In FIG. 5, the time section in which the accumulated power generation time of the cell stack 24 is 0 to 5000 hours is referred to as “first section” as in FIG. 3. Further, in FIG. 5, the time section in which the accumulated power generation time of the cell stack 24 is 5000 to 30000 hours is referred to as “second section” as in FIG. 3.

  On the other hand, in FIG. 5, the time section in which the accumulated power generation time of the cell stack 24 is 30000-70000 hours is referred to as “third section”. Further, in FIG. 5, unlike FIG. 3, a time section of about 70000 hours to 90000 hours approaching the end of the time during which the accumulated power generation time of the cell stack 24 can generate power is referred to as “fourth section”.

  In the example shown in FIG. 5, when the current value of the current generated by the cell stack 24 is 11 [A], the target temperature close to the case of the rated output shown in FIG. Is set. In the example shown in FIG. 5, when the current value of the current generated by the cell stack 24 is 5 [A], the period from the first division to the third division is the case of 5 [A] shown in FIG. A target temperature close to is set. In the example shown in FIG. 5, when the current value of the current generated by the cell stack 24 is 0 [A], the same target temperature is set between the first section and the fourth section.

That is, in the example shown in FIG. 5, when the current generated by the cell stack 24 is 0 [A], the target temperature is set as follows in each time segment.
1st to 4th divisions: maintained at 660 ° C

In the example shown in FIG. 5, when the current generated by the cell stack 24 is 5 [A], the target temperature is set as follows in each time segment.
1st division: rising from 665 ° C to 670 ° C 2nd division: rising from 670 ° C to 675 ° C 3rd division: keeping at 675 ° C 4th division: rising from 675 ° C to 680 ° C

Similarly, in the example shown in FIG. 5, when the current generated by the cell stack 24 is rated (about 11 [A]), the target temperature is set as follows in each time segment.
1st division: rising from 670 ° C to 680 ° C 2nd division: rising from 680 ° C to 690 ° C 3rd division: keeping at 690 ° C 4th division: rising from 690 ° C to 700 ° C

  As described above, in the present embodiment, the control unit 10 increases the temperature in the vicinity of the cell stack 24 in the time segment (for example, the fourth segment) after the second segment than in the second segment. You may control as follows. Here, the time section (for example, the fourth section) after the second section may be set based on the time during which the cell stack 24 can generate power. In addition, the fourth division is preferably a time division in which deterioration due to the end of the power generation possible time of the cell stack 24 approaches (for example, an integrated power generation time of about 70000 hours to 90000 hours). . Furthermore, it is desirable to appropriately set the magnitude of the increase in the target temperature of the cell stack 24 so as to increase the power generation efficiency in consideration of various factors such as the characteristics of the cell stack 24. For example, the magnitude of the increase in the target temperature can be appropriately set based on the result of a test in which a cell stack of the same type as the cell stack 24 is operated until the end of the power generation time.

  Even if it controls as demonstrated above, according to the electric power generating apparatus 1 concerning this embodiment, electric power generation efficiency can be improved.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various variations and modifications based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each functional unit, each means, each step, etc. can be rearranged so that there is no logical contradiction, and a plurality of functional units, steps, etc. are combined or divided into one. It is possible. In addition, each of the embodiments of the present invention described above is not limited to being performed faithfully to each of the embodiments described above, and is implemented by appropriately combining the features or omitting some of the features. You can also.

  For example, the target temperature shown in FIGS. 3 and 5 is shown as a graph that changes linearly (linearly) for each time segment. However, the target temperature shown in FIGS. 3 and 5 is merely an example, and may change so as to be able to be shown as a graph that changes in a curved manner for each time segment, for example. In addition, in FIGS. 3 and 5, the target temperature value shown for each current value is merely an example. It is preferable to appropriately set the target temperature so that the efficiency of power generation performed by the cell stack is increased in consideration of the result of the test actually generated in the cell stack.

  In the power generation apparatus 1 shown in FIG. 1, the target temperature is set based on the “current” detected by the current sensor 70 and generated by the cell stack 24. However, in the power generation device according to the present embodiment, the target temperature may be set based on the “voltage” generated by the cell stack 24. In this case, instead of the current sensor 70, it is preferable to install a voltmeter at a position where the voltage generated by the cell stack 24 can be detected. Further, the control unit 10 may set the target temperature to increase more in the first section than in the second section when the voltage generated by the cell stack 24 is constant.

  In the above disclosure, the power generation apparatus 1 including the cell stack 24 serving as the SOFC has been described as the present embodiment. However, as described above, the power generation device 1 according to the present embodiment is not limited to the one provided with the SOFC, and may include various fuel cells such as a PEFC without a module. In the present disclosure, the “fuel cell” means, for example, a power generation system, a power generation unit, a fuel cell module, a hot module, a cell stack, or a cell. Therefore, in the present disclosure, the vicinity of the fuel cell can be, for example, the vicinity of the cell stack 24. In the present disclosure, the operation time of the fuel cell can be, for example, the operation time of the cell stack 24 or the fuel cell module 20.

  In the above disclosure, the power generation apparatus 1 including a fuel cell has been described as the present embodiment. However, the embodiment of the present disclosure is not limited to the power generation device 1 including a fuel cell.

  For example, the embodiment of the present disclosure can be realized as a fuel cell control device that controls a fuel cell from the outside without including the fuel cell. An example of such an embodiment is shown in FIG. As shown in FIG. 6, the fuel cell control device 2 according to this embodiment includes, for example, a control unit 10 and a storage unit 12. The control device 2 controls the external fuel cell 1. That is, the fuel cell control device 2 according to the present embodiment controls the temperature in the vicinity of the fuel cell in accordance with the operating time of the fuel cell. Further, the fuel cell control device 2 performs control so that the temperature increase in the vicinity of the fuel cell is larger in the first section than in the second section.

  Furthermore, the embodiment of the present disclosure can also be realized as a control program to be executed by the fuel cell control device 2 as described above, for example. That is, the fuel cell control program according to the present embodiment causes the control device 2 that controls the fuel cell to execute a step of controlling the temperature in the vicinity of the fuel cell according to the operating time of the fuel cell. In addition, the control program causes the control device 2 to execute a step of controlling the temperature in the vicinity of the fuel cell to be greater in the first section than in the second section.

DESCRIPTION OF SYMBOLS 1 Power generator 2 Control apparatus 10 Control part 12 Memory | storage part 20 Fuel cell module 22 Reformer 24 Cell stack 30 Supply part 32 Gas supply part 34 Air supply part 36 Reformed water supply part 40 Inverter 50 Waste heat recovery process part 52 Circulation Water treatment unit 60 Hot water storage tank 70 Current sensor 80 Temperature sensor 100 Load 200 Commercial power supply

Claims (12)

A fuel cell;
A control unit for controlling the temperature in the vicinity of the fuel cell;
A power generator comprising:
The control unit controls the temperature in the vicinity of the fuel cell according to the operation time of the fuel cell, and in the time segment of the operation initial stage of the fuel cell, compared to the time segment next to the time segment of the initial operation period, A power generation device that controls the temperature of the fuel cell to increase so as to increase.   The power generation device according to claim 1, wherein the time division of the initial operation of the fuel cell is set based on an influence of initial deterioration of the fuel cell.   The control unit controls a temperature in the vicinity of the fuel cell by referring to a target temperature set based on an operation time of the fuel cell and a current or voltage generated by the fuel cell. The power generator described in 1.   When the current or voltage generated by the fuel cell is constant, the control unit increases the target temperature in the initial time segment more than in the next time segment after the initial operation time segment. The power generation device according to claim 3, which is set to be A current sensor for detecting a current generated by the fuel cell;
The power generation device according to claim 4, wherein the control unit sets the target temperature based on a current generated by the fuel cell detected by the current sensor. A temperature sensor for detecting the temperature in the vicinity of the fuel cell;
The power generation device according to claim 3, wherein the control unit controls a temperature in the vicinity of the fuel cell based on the target temperature and a temperature detected by the temperature sensor. An air supply unit for supplying air used for an electrochemical reaction when the fuel cell generates electricity;
The power generation device according to claim 1, wherein the control unit controls the temperature in the vicinity of the fuel cell by adjusting the air supplied by the air supply unit. A gas supply unit for supplying raw fuel gas used in an electrochemical reaction when the fuel cell generates power;
The power generation device according to claim 1, wherein the control unit controls a temperature in the vicinity of the fuel cell by adjusting a gas supplied from the gas supply unit.   The control unit may increase the temperature in the vicinity of the fuel cell in a time segment subsequent to the time segment next to the initial operation time period than in a time segment subsequent to the initial operation time period. The power generator according to any one of claims 1 to 8, wherein   10. The power generation device according to claim 1, wherein a time segment after a time segment next to the initial operation time segment is set based on a time during which the fuel cell can be operated.   The temperature in the vicinity of the fuel cell is controlled in accordance with the operating time of the fuel cell. A control device for a fuel cell that controls the increase of the fuel cell. In the control device that controls the fuel cell,
Controlling the temperature in the vicinity of the fuel cell according to the operating time of the fuel cell;
In the initial operation time section of the fuel cell, the step of controlling the temperature increase in the vicinity of the fuel cell to be larger than the time section next to the initial operation time section;
A fuel cell control program.

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