Power supply system

Abstract

To provide a power supply system that comprises a fuel cell system and a secondary battery and can improve start-up responsiveness.SOLUTION: A control unit 14 calculates start-up required power Preq as power required for starting up fuel cell systems (FCS) 16. The control unit 14 sets priority indicating the order of start-up to the plurality of FCSs 16 according to the temperature of the FCSs 16, the start-up required power Preq, and the remaining capacity of a battery 20, and starts up the plurality of FCSs 16 according to the priority.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply system. [Background technology]

[0002] In recent years, research and development into fuel cells has been conducted to contribute to energy efficiency in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Japanese Patent Application Laid-Open Publication No. 2017-126441 discloses a power supply system having multiple fuel cell systems, which selects one of the inactive fuel cell systems with the highest temperature and starts the selected fuel cell system first. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-126441 Summary of the Invention [Problem to be solved by the invention]

[0005] In such a power supply system, improvement in startup response is desired.

[0006] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0007] One aspect of the present invention is a power supply system having a secondary battery connected to a load, a plurality of fuel cell systems connected to the load and the secondary battery, and a control device that controls the startup of the plurality of fuel cell systems and the supply of power to the load, and further having a remaining capacity acquisition device that acquires the remaining capacity of the secondary battery, and a temperature acquisition device that acquires the temperature of the fuel cell system, wherein the control device calculates a required startup power as the power needed to start the fuel cell system, and sets priorities indicating the order of startup for the plurality of fuel cell systems based on the temperature of the fuel cell system, the required startup power, and the remaining capacity of the secondary battery, and starts up the plurality of fuel cell systems in accordance with the priorities. [Effects of the Invention]

[0008] According to the present invention, the startup response of the power supply system can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a power supply system according to an embodiment. [Figure 2] FIG. 2 is a flowchart illustrating the startup process of the power supply system shown in FIG. [Figure 3] FIG. 3 is a flowchart illustrating a subroutine for calculating the number of fuel cell systems (FCS) that can be started. [Figure 4] FIG. 4 is a flowchart illustrating a subroutine for setting the startup mode of the FCS. [Figure 5] FIG. 5 is a flowchart illustrating a subroutine for calculating the power value that the power supply system can output. [Figure 6] FIG. 6 is a flowchart illustrating a subroutine for setting priorities in simultaneous activation mode. [Figure 7] FIG. 7 is a flowchart illustrating a subroutine for instructing the FCS to start up. [Figure 8] FIG. 8 is a flowchart illustrating a subroutine for determining whether the startup of the power supply system is complete. [Figure 9] FIG. 9 is a flowchart illustrating a subroutine for setting priorities in the priority startup mode. [Figure 10] FIG. 10 is a flowchart illustrating a subroutine for setting priorities for one or more FCSs. [Figure 11] FIG. 11 is an explanatory diagram showing an example of the relationship between the temperature of the FCS and the power required to start the FCS. [Figure 12] Fig. 12A is an explanatory diagram showing an example of the timing of completion of activation of the FCS shown in Fig. 11 and transition of power available for activation of the FCS. Fig. 12B is an explanatory diagram showing an example of priorities set for the FCS. [Figure 13] FIG. 13 is a timing chart showing an example of the timing of the start-up completion of the FCS and the start-up completion of the power supply system. [Figure 14] FIG. 14 is a flowchart illustrating a startup process of a power supply system according to a modified example. [Figure 15] FIG. 15 is a flowchart illustrating a subroutine for setting a priority for one FCS. DETAILED DESCRIPTION OF THE INVENTION

[0010] FIG. 1 is a block diagram showing an example of the configuration of a power supply system 10 according to an embodiment. Here, the power supply system 10 is explained as a fuel cell vehicle (FCV) 12 that is propelled (runs) using power generated by a fuel cell. However, the power supply system 10 is not limited to the fuel cell vehicle 12. The power supply system 10 may also be a moving body other than a vehicle, such as a ship, an aircraft, or a robot. The power supply system 10 may also be a stationary power source installed in a business facility or a home.

[0011] <Configuration of power supply system 10> As shown in FIG. 1, the power supply system 10 includes a control device 14, a fuel cell system (FCS) 16, a fuel cell voltage control unit (FCVCU) 18, a battery 20, a battery voltage control unit (BATVCU) 22, a power drive unit (PDU) 24, a motor 26, and a transmission (T / M) 28.

[0012] The power supply system 10 includes multiple FCSs 16. The FCSs 16 include fuel cell stacks and various devices used in the operation of the fuel cell stacks.

[0013] The fuel cell stack includes a plurality of fuel cells (power generation cells). The plurality of fuel cells generate electricity through an electrochemical reaction between fuel gas and oxidant gas, and output electric power. The FCS 16 outputs the electric power output by the fuel cell stack. The electric power output from the FCS 16 is supplied to a load such as a motor 26, and is also used to charge the battery 20.

[0014] The FCS 16 includes auxiliary equipment (not shown) and a temperature sensor 32 as devices used in the operation of the fuel cell stack.

[0015] The auxiliary equipment supplies fuel gas and oxidant gas to the fuel cell stack. The auxiliary equipment includes a hydrogen tank, an air pump, a coolant system, valves, piping, and other associated devices. The FCS 16 may also include a heater as an auxiliary equipment for heating the fuel cell stack.

[0016] The temperature sensor 32 acquires the temperature of the FCS 16 and outputs a signal indicating the acquired temperature to the control device 14. The temperature of the FCS 16 can be detected, measured, or estimated, for example, from the representative temperature of each power generation cell, the coolant temperature, the oxidant gas temperature, etc. The power supply system 10 can employ a known configuration as the temperature acquisition means for the FCS 16.

[0017] The FCS 16 includes various sensors, such as a current sensor (not shown) and a voltage sensor (not shown), and has a function of calculating the power that the FCS 16 can currently output. The FCS 16 outputs the calculated value of the power that the FCS 16 can currently output to the control device 14 (in the following description, the power that the FCS 16 can currently output is referred to as the available output power Pfc). The FCS 16 also has a function of detecting an abnormality within the FCS 16. The FCS 16 outputs a signal indicating the presence or absence of an abnormality in the FCS 16 to the control device 14.

[0018] The FCVCU 18 is a boost converter that boosts the voltage of the power output by the FCS 16 and outputs it to the BATVCU 22. This power supply system 10 includes one FCVCU 18 for each FCS 16.

[0019] The power supply system 10 includes one or more batteries 20. The batteries 20 are secondary batteries that can charge and discharge power. The batteries 20 supply power to loads such as a motor 26, and are charged by power output from the FCS 16 and regenerative power from the motor 26.

[0020] The battery 20 is equipped with various sensors, such as a current sensor (not shown) and a voltage sensor (not shown). Measurement values ​​from these sensors are output to the control device 14. The control device 14 estimates the remaining capacity of the battery 20 based on these measurements and other information. That is, the control device 14 functions as a remaining capacity acquisition device for the battery 20. However, the means for acquiring the remaining capacity of the battery 20 is not limited to this, and various known means can be used.

[0021] The BATVCU 22 is a step-up / step-down converter that boosts and adjusts the voltage of the power output by the battery 20 and the FCVCU 18, and outputs the voltage to the PDU 24. The BATVCU 22 boosts or lowers the power output by the FCVCU 18 to a voltage suitable for charging the battery 20, and outputs the voltage to the battery 20.

[0022] The PDU 24 is an inverter that converts the input power into a frequency and voltage suitable for the rotation speed and torque of the motor 26 and outputs the converted power to the motor 26 .

[0023] The motor 26 is an electric motor that operates using input power and converts the power into driving force (rotational force) and outputs the driving force. The motor 26 is an example of a load that requests the FCS 16 to supply power.

[0024] The T / M 28 is a transmission that adjusts the torque of the rotational force output by the motor 26 and transmits it to the wheels 30 .

[0025] The control device 14 is a computer that controls the power supply system 10. The control device 14 can supervise all components of the power supply system 10 and execute the operation of the power supply system 10.

[0026] The control device 14 includes, for example, a calculation unit (processing unit) and a storage unit.

[0027] The calculation unit may be configured by a processor such as a central processing unit (CPU), a graphics processing unit (GPU), etc. In other words, the calculation unit may be configured by processing circuitry.

[0028] The calculation unit includes functional units such as a determination unit, a remaining battery capacity acquisition unit, a power calculation unit, a startup mode setting unit, a priority setting unit, a startup start determination unit, and an output limiting unit. These functional units can be realized by the calculation unit executing computer-executable instructions (programs) stored in the storage unit.

[0029] At least a part of the calculation unit may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), or may be configured by an electronic circuit including discrete devices.

[0030] The storage unit may be composed of a volatile memory (not shown) and a nonvolatile memory (not shown). Examples of the nonvolatile memory include a ROM (Read Only Memory) and a flash memory. The nonvolatile memory is used as a storage memory and stores programs, tables, maps, etc. The volatile memory may include a RAM (Random Access Memory), etc. The volatile memory is used as a working memory for the processor and temporarily stores data, etc., required for processing or calculation. At least a part of the storage unit may be provided in the processor, integrated circuit, etc. described above.

[0031] <Description of Operation Related to Start-Up Process of Power Supply System 10> The power supply system 10 is basically configured as described above. Next, the operation of the startup process of the power supply system 10 will be described with reference to the flowchart of FIG.

[0032] Figure 2 is a flowchart illustrating the startup process of the power supply system 10 shown in Figure 1. The control device 14 starts the startup process of the power supply system 10 when it receives a startup instruction, such as an instruction from a user to start operating the fuel cell vehicle 12, for example.

[0033] In step S10, the control device 14 calculates the number of FCSs 16 that can be activated (hereinafter, the number of FCSs 16 will be referred to as the base number or the number of systems). The subroutine called in step S10 is shown in FIG.

[0034] Fig. 3 is a flowchart illustrating a subroutine for calculating the cardinal number of the activatable FCS 16. In step S11 of Fig. 3, the control device 14 acquires the cardinal number of the FCS 16 installed in the power supply system 10. The control device 14 can acquire, for example, from a storage unit, the installed cardinal number of the FCS 16 stored in advance in the storage unit.

[0035] In step S12, the control device 14 acquires the number of faulty FCSs 16. The control device 14, for example, inquires of each FCS 16 about whether or not there is a fault. The control device 14 can acquire the number of faulty FCSs 16 based on the number of abnormality signals received from each FCS 16. An abnormality in an FCS 16 means a state in which the FCS 16 cannot start up normally, and includes, for example, a failure of the air pump or valve, cross-leakage within the fuel cell stack, etc.

[0036] In step S13, the control device 14 subtracts the faulty radix from the installed radix of the FCS 16 to calculate the radix of the startable FCS 16. At this time, the control device 14 acquires the address of each FCS 16 and can identify the FCS 16 that can be started normally.

[0037] After step S13, the control device 14 executes the startup process for the normal FCS 16. That is, in step S13, the control device 14 excludes the faulty FCS 16 from the startup process of the power supply system 10. In the following description, the term "FCS 16" is used to mean "an FCS 16 that can be started normally" unless otherwise specified.

[0038] 2, in step S20, the controller 14 sets the startup mode of the FCS 16. The subroutine called in step S20 is shown in FIG.

[0039] Fig. 4 is a flowchart illustrating a subroutine for setting the startup mode of the FCS 16. In step S21 of Fig. 4, the control device 14 acquires the remaining capacity of the battery 20. The control device 14 can acquire the remaining capacity of the battery 20 based on measurements from a current sensor (not shown) and a voltage sensor (not shown) provided in the battery 20, and a map stored in a memory unit, etc.

[0040] In step S22, the controller 14 acquires the temperature of the FCS 16 from the temperature sensor 32.

[0041] In step S23, the control device 14 calculates the power value required for startup of each FCS 16 based on the temperature of the FCS 16. The control device 14 can calculate the power value required for startup of the FCS 16, for example, from the temperature of the FCS 16 and a map stored in the storage unit. In the following description, the power value required for startup of the FCS 16 is referred to as "power required for startup Preq."

[0042] In step S24, controller 14 calculates the power value that can be output by power supply system 10. The subroutine called in step S24 is shown in FIG.

[0043] Fig. 5 is a flowchart illustrating a subroutine for calculating the power output value that can be output by power supply system 10. In step S41 of Fig. 5, control device 14 calculates the power output value that can be output by power supply system 10 (hereinafter, the power output value that can be output by power supply system 10 will be referred to as "output power Pall"). Control device 14 may, for example, calculate the sum of the output power Pfc of each FCS 16 and use this as the output power Pall of power supply system 10 (Pall = ΣPfc).

[0044] The available output power Pfc that can be output by an unactivated FCS 16 is 0 (zero). Therefore, in the initial state, the available output power Pall of the power supply system 10 is also 0 (zero).

[0045] 4, in step S25, the control device 14 determines whether simultaneous activation is possible for all of the FCSs 16. The control device 14 can determine whether simultaneous activation is possible based on, for example, the remaining capacity of the battery 20 and the power Preq required to activate the FCSs 16.

[0046] If the battery 20 has sufficient remaining capacity and can supply the power Preq required for activation to all of the FCSs 16, the control device 14 can determine that all of the FCSs 16 can be activated simultaneously (step S25: YES). In this case, the control device 14 transitions to the simultaneous activation mode in step S26. The subroutine called in step S26 is shown in FIG. 6.

[0047] 6 is a flowchart illustrating a subroutine for setting the priority (priority order) in simultaneous startup mode. Here, the priority of the FCS 16 refers to the order in which the FCS 16 is started. That is, an FCS 16 with a higher priority is started earlier than other FCSs 16. In the following description, the term "priority order" may be used to specify the order of startup, but "priority order" and "priority order" are both used interchangeably.

[0048] The power supply system 10 according to this embodiment allows the same priority (order of precedence) to be set for multiple FCSs 16. For example, when the same priority (order of precedence) is set for multiple FCSs 16, the multiple FCSs 16 are activated simultaneously.

[0049] When the simultaneous activation mode is entered, the control device 14 sets "Priority 1 (Priority Order 1)" for all FCSs 16 in step S261 of Fig. 6. Priority order 1 means "first in priority order." That is, in the simultaneous activation mode, all FCSs 16 can be activated at the same time.

[0050] 4, for example, when the remaining capacity of the battery 20 is low, the battery 20 cannot supply the activation power Preq to all of the FCSs 16. The control device 14 can determine that all of the FCSs 16 cannot be activated simultaneously (step S25: NO).

[0051] In this case, the control device 14 transitions to a priority startup mode in step S27. In the priority startup mode, one or more FCSs 16 are selected based on the temperature, and the selected FCSs 16 are started sequentially in priority to the other FCSs 16. The priority startup mode will be described in detail later.

[0052] Returning to the process shown in Fig. 2, in step S30, the control device 14 issues a startup instruction (startup request) to the FCSs 16 according to the startup mode. Here, the explanation will be continued assuming the "simultaneous startup mode." That is, the explanation will be continued assuming that "priority 1 (first priority)" is set for all FCSs 16. The subroutine called in step S30 is shown in Fig. 7.

[0053] 7 is a flowchart illustrating a subroutine for instructing the start of startup to the FCS 16. The control device 14 instructs the FCS 16 to start startup in accordance with priority (priority order).

[0054] In step S31, the control device 14 determines whether the FCS 16 assigned "priority 1 (first priority)" has completed startup. The completion of startup of the FCS 16 can be determined, for example, by whether the temperature of the FCS 16 is equal to or higher than a predetermined value (e.g., equal to or higher than 80 degrees Celsius). Here, the explanation will continue assuming that the FCS 16 assigned "priority 1 (first priority)" has not yet started (step S31: NO).

[0055] In step S32, the control device 14 issues a startup instruction to the FCS 16 that has been assigned "priority 1 (first priority)." Here, it is assumed that "first priority" is set to all FCSs 16, so all FCSs 16 that can be started normally start the startup process all at once.

[0056] 2, in step S40, controller 14 calculates the available output power Pall of power supply system 10. The subroutine called in step S40 is shown in FIG.

[0057] In step S41, the control device 14 sets the total available output power Pfc of the FCSs 16 that have completed startup as the available output power Pall of the power supply system 10. Here, since each FCS 16 has just started startup, the available output power Pfc is 0 and the available output power Pall of the power supply system 10 is also 0.

[0058] 2, in step S50, controller 14 determines whether or not startup of the entire power supply system 10 is complete. The subroutine called in step S50 is shown in FIG.

[0059] Fig. 8 is a flowchart illustrating a subroutine for determining the completion of startup of the power supply system 10. In step S51 of Fig. 8, the control device 14 determines whether startup of all FCSs 16 has been completed.

[0060] If the startup of all FCSs 16 is not complete (step S51: NO) and the startup wait time has not elapsed (step S52: NO), the status flag of the power supply system 10 is set to "startup incomplete flag" in step S55.

[0061] 2, it is determined again in step S60 that the startup of all FCSs 16 has not been completed (step S60: NO).The process returns to step S10, and the startup process of the FCSs 16 is repeatedly executed until the startup of all FCSs 16 is completed.

[0062] In step S51 of FIG. 8, if it is determined that the startup of all FCSs 16 is complete (step S51: YES), the status flag of the power supply system 10 is set to a "startup completion flag" in step S54.

[0063] 2, and it is determined again in step S60 that the startup of all FCSs 16 has been completed (step S60: YES). The startup process of the power supply system 10 ends. The power supply system 10 starts operation and can start supplying power to the load.

[0064] In step S51 of FIG. 8, even if all FCSs 16 have not completed startup (step S51: NO), if the startup wait time has elapsed (step S52: YES) and the available output power Pall of the power supply system 10 has reached or exceeded the power required by the load (step S53: YES), the control device 14 sets the status flag of the power supply system 10 to a "startup completion flag" (step S54).

[0065] In this case, the power supply system 10 starts operation and can start supplying power to the load with the available output power Pfc of the activated FCS 16. Meanwhile, the activation process for the inactive FCSs 16 is repeatedly executed until activation of all FCSs 16 is completed.

[0066] In this way, the power supply system 10 according to this embodiment can start supplying power to the load within the range of the available output power Pfc of the activated FCSs 16, without waiting for the activation of all of the FCSs 16. In other words, this power supply system 10 can start supplying power more quickly than when the power supply is started after the activation of all of the FCSs 16 has been completed.

[0067] <Explanation of priority startup mode> Next, the "priority startup mode" will be described in detail with reference to Figures 4, 9, and 10. The "priority startup mode" is a mode entered when it is determined in step S25 of Figure 4 that simultaneous startup of all FCSs 16 is not possible. The subroutine called in step S27 of Figure 4 is shown in Figure 9.

[0068] FIG. 9 is a flowchart illustrating a subroutine for setting priorities (priority levels) in the priority startup mode.

[0069] 9, the control device 14 determines whether or not the startup process has been completed for all FCSs 16. Here, it is assumed that all FCSs 16 have not yet started startup, and it is determined that the startup process for all FCSs 16 has not been completed (step S71: NO).

[0070] In step S72, the control device 14 determines whether the FCS 16 assigned "priority 1 (first priority)" has completed startup. Here, it is assumed that there is no FCS 16 assigned "first priority," and it is determined that the FCS 16 assigned "first priority" has not completed startup (step S72: NO).

[0071] In step S73, the control device 14 sets "priority 1 (first priority)" to one or more FCSs 16. The subroutine called in step S73 is shown in FIG.

[0072] FIG. 10 is a flowchart illustrating a subroutine for setting priority N (Nth priority) to one or more FCSs 16.

[0073] 10, the control device 14 calculates the power available for starting the FCS 16. Hereinafter, the power available for starting the FCS 16 will be referred to as "start-up available power Pavbl."

[0074] The available power for startup Pavbl is basically the power that the battery 20 can supply to the FCS 16. However, if there is an activated FCS 16, it is preferable that the power that the activated FCS 16 can output (the available output power Pfc) is also used to activate the other FCS 16. In other words, the available power for startup Pavbl can include the available output power Pfc of the activated FCS 16.

[0075] In step S82, the control device 14 selects one FCS 16 with the highest temperature from among the multiple FCSs 16 for which no priority (priority order) has been set. An FCS 16 with a high temperature requires less heating time using a heater, for example, and therefore requires less power to start up, and is expected to be able to start up in a short time. In the following description, an FCS 16 for which no priority (priority order) has been set may be referred to as an FCS 16 that has not yet acquired a priority order.

[0076] For ease of explanation, the FCS16 selected first in step S82 will be referred to as FCS16-1, and similarly, the FCS16 selected Mth will be referred to as FCS16-M. Here, the explanation will continue for the case where M=1, i.e., the first selected FCS16-1.

[0077] In step S83, the control device 14 determines whether the available startup power Pavbl that can be used to start up FCS 16-1 is equal to or greater than the required startup power Preq that is required to start up FCS 16-1. If the available startup power Pavbl is equal to or greater than the required startup power Preq of FCS 16-1 (step S83: YES), in step S84, "priority N (Nth priority)" is set to FCS 16-1. Here, the explanation will continue assuming that N=1, that is, the control device 14 sets "priority 1 (first priority)" to FCS 16-1.

[0078] In step S85, the control device 14 subtracts the required power Preq for starting the FCS 16-1, which is set to "priority 1 (first priority)," from the available power Pavbl for starting. The control device 14 sets the value after the subtraction as the new available power Pavbl for starting.

[0079] Returning to step S82, the control device 14 selects one FCS 16-2 having the highest temperature from among the plurality of FCSs 16 for which no priority (order of priority) is set.

[0080] In step S83, if the new available power for startup Pavbl is equal to or greater than the power required for startup Preq of FCS 16-2 (step S83: YES), in step S84, the control device 14 sets "priority 1 (first priority)" for FCS 16-2. That is, the control device 14 sets "priority 1 (first priority)" for the two FCSs 16, FCS 16-1 and FCS 16-2. In step S85, the control device 14 updates the value of the available power for startup Pavbl, and returns the process to step S82.

[0081] In this way, the processes from step S82 to step S85 are repeatedly executed on the condition that the available power for startup Pavbl is equal to or greater than the power required for startup Preq of the FCS 16-M. As a result, "priority 1 (first in priority order)" is set for one FCS 16 or two or more but M or less FCSs 16.

[0082] If the available power for startup Pavbl falls below the power required for startup Preq of FCS16-M (step S83: NO), it is determined that the remaining capacity of battery 20 is not enough to cover the power required for startup Preq of FCS16-M, and the setting process for "Priority 1 (first priority)" is terminated.

[0083] 9, the control device 14 sets "priority 0 (0th priority)" to the FCS 16 other than the FCS 16 to which "priority 1 (1st priority)" was set in step S74. "Priority 0 (0th priority)" means that no priority has been acquired, that is, a state in which a priority is waiting to be set.

[0084] Returning to the processing shown in FIG. 2, the control device 14 calls the subroutine shown in FIG. 7 in step S30.

[0085] In steps S31 and S32 of FIG. 7, the control device 14 issues start-up instructions to the M FCSs 16-1 to 16-M that are set to "priority 1 (first priority)."

[0086] Returning to the processing shown in Fig. 2, in step S40, controller 14 calls the subroutine shown in Fig. 5. In step S41 of Fig. 5, controller 14 calculates the allowable output power Pall of power supply system 10.

[0087] Returning to the process shown in Fig. 2, in step S50, control device 14 calls the subroutine shown in Fig. 8. Control device 14 determines whether startup of power supply system 10 is complete based on the subroutine shown in Fig. 8. If a predetermined condition is met (step S53: YES), power supply to the load can be started.

[0088] Regardless of whether or not power supply to the load is started, the control device 14 repeatedly executes the startup process in the priority startup mode until startup of all FCSs 16 is completed (step S60: NO).

[0089] That is, in the priority startup mode, when an FCS16 set with priority N-1 (N-1th priority) completes startup (step S75 in Figure 9: YES), the control device 14 sets "priority N (Nth priority)" to one or more FCS16 in step S77.

[0090] 10 on the condition that the available power for startup Pavbl is equal to or greater than the power required for startup Preq of the FCS 16. As a result, a higher priority (order of precedence) is set to one or more FCSs 16 in descending order of temperature, and one or more FCSs 16 can start startup in accordance with the priority (order of precedence).

[0091] In this way, in the priority startup mode, even if the remaining capacity of the battery 20 is insufficient, one or more FCSs 16 with high temperatures are started preferentially within the range of the remaining capacity of the battery 20, so that the power supply system 10 can be started quickly.

[0092] <Example of boot process in priority boot mode> Next, an example of the startup process in the priority startup mode will be described in chronological order with reference to FIGS.

[0093] Fig. 11 is an explanatory diagram showing an example of the relationship between the temperatures of the four FCSs 16 and the startup required power Preq [kW] required to start each FCS 16. To distinguish the four FCSs 16 from one another, the names FCS#1, FCS#2, FCS#3, and FCS#4 are used in Fig. 11. As shown in the second and third rows of Fig. 11, the higher the temperature of the FCS 16, the smaller the startup required power Preq, and the lower the temperature of the FCS 16, the larger the startup required power Preq.

[0094] 11 shows the power [kW] that the battery 20 can output, and the fifth row shows the available output power Pfc [kW] that each FCS 16 can output after startup. The sum of the power that the battery 20 can output and the available output power Pfc of each FCS 16 corresponds to the available startup power Pavbl [kW] calculated in step S81 in Fig. 10. In other words, the available startup power Pavbl is the power that the power supply system 10 can use to start up an FCS 16 that has not yet been started.

[0095] Fig. 12A is an explanatory diagram showing an example of the timing of startup completion of the FCSs 16 (FCS#1 to FCS#4) shown in Fig. 11 and transition of the startup available power Pavbl. Fig. 12B is an explanatory diagram showing an example of the priority (priority order) set for each FCS 16.

[0096] 12A and 12B, the start-up process of the power supply system 10 begins. At time t0, none of the four FCSs 16 have started up.

[0097] As shown in Fig. 11, the output power (15 kW) of the battery 20 is smaller than the total power Preq required to start the four FCSs 16 (10 kW + 15 kW + 15 kW + 20 kW = 60 kW). That is, the battery 20 cannot supply the power required to start all four FCSs 16 at once (step S25 in Fig. 4: NO). For this reason, the control device 14 transitions to the priority start-up mode.

[0098] When the output power (15 kW) of battery 20 is compared with the power required for activation Preq (10 kW) of FCS#1, which has the highest temperature, the former is greater than the latter (step S83 in FIG. 10: YES). Therefore, as shown in FIG. 12B, at time t0, control device 14 sets "priority 1 (first priority)" for FCS#1.

[0099] The value obtained by subtracting the power Preq (10 kW) required to start FCS#1 from the output power (15 kW) of battery 20 is 5 kW. This 5 kW is smaller than the power Preq (15 kW) required to start FCS#2, which has the second highest temperature. The same is true for FCS#3, which is at the same temperature as FCS#2. In other words, battery 20 cannot supply the power required to start FCS#2, nor can it supply the power required to start FCS#3. Control device 14 sets "priority 0 (0th priority)" for the three units other than FCS#1 and instructs FCS#1 to begin startup.

[0100] When startup of FCS#1 is completed at time t1, the startup available power Pavbl increases by the amount of FCS#1's output available power Pfc (10 kW) to 25 kW. Power supply system 10 can cover the startup required power Preq (15 kW) of FCS#2 with the new startup available power Pavbl (step S83: YES). FCS#2 is set to "priority 2 (second highest priority)" and startup of FCS#2 begins.

[0101] When startup of FCS#2 is completed at time t2, the startup available power Pavbl increases further by the amount of FCS#2's available output power Pfc (10 kW), to 35 kW. Power supply system 10 can use the new startup available power Pavbl to cover the startup required power Preq (15 kW) of FCS#3 and the startup required power Preq (15 kW) of FCS#4 (step S83: YES). FCS#3 and FCS#4 are assigned "priority 3 (third highest priority)," and startup of FCS#3 and FCS#4 begins.

[0102] When the startup of FCS#3 and FCS#4 is completed at time t3, the available startup power Pavbl increases by the available output power Pfc (10 kW) of FCS#3 and the available output power Pfc (10 kW) of FCS#4, to 55 kW. When the startup of all four FCSs 16 is completed (step S60: YES), the control device 14 ends the startup process of the power supply system 10.

[0103] <Example of power supply system startup completion determination process> Next, with reference to FIG. 13, an example of a process performed by control device 14 to determine whether startup of power supply system 10 has been completed will be described in chronological order.

[0104] 13 is a timing chart showing an example of the timing of the start-up completion of the four FCSs 16 and the start-up completion of the power supply system 10. To distinguish the four FCSs 16 from one another, the names FCS#5, FCS#6, FCS#7, and FCS#8 are used in FIG.

[0105] At time t4, the control device 14 receives a startup signal (start-up request) for the power supply system 10 from the load and starts the startup process of the power supply system 10. The control device 14 instructs each FCS 16 to start startup in, for example, a priority startup mode. However, the control device 14 may also instruct each FCS 16 to start startup in a simultaneous startup mode.

[0106] At time t5, the startup wait time elapses. At time t5, three FCSs 16, FCS#5, FCS#7, and FCS#6, have completed startup, but FCS#8 has not yet started.

[0107] Control device 14 adds up the available output power Pfc [kW] of the three units, FCS#5, FCS#7, and FCS#6, for which startup has been completed, to calculate a total value (step S41 in FIG. 5). This total value corresponds to the available output power Pall [kW] that power supply system 10 can output. If the available output power Pall of power supply system 10 is equal to or greater than the power required by the load (step S53 in FIG. 8: YES), control device 14 sets the status flag of power supply system 10 to a "startup completion flag."

[0108] When the startup completion flag is set, the control device 14 can determine that the startup process of the power supply system 10 is complete. The control device 14 raises the output limit value [kW] of the power supply system 10 from 0 to the available output power Pall. In other words, the control device 14 relaxes the output limit of the power supply system 10. This allows the power supply system 10 to start supplying power to the load. However, the startup process for the FCS#8 that has not yet started continues.

[0109] At time t6, when startup of FCS#8 is complete, control device 14 adds the available output power Pfc of FCS#8 to the available output power Pall of power supply system 10. Power supply system 10 raises the output limit value to the available output power Pall after the addition. This enables power supply system 10 to supply power at maximum output to the load. When startup of all four FCSs 16 is complete, control device 14 ends the startup process of power supply system 10.

[0110] The temperature and ease of warming up of the FCS 16 may vary depending on the installation location of the FCS 16. However, the power supply system 10 according to this embodiment can start supplying power to the load when the available output power Pall reaches the power required by the load. This allows for the power supply to start promptly without waiting for all of the FCSs 16 to finish starting up.

[0111] <Description of Modifications> Next, a power supply system 100 according to a modification will be described with reference to Figures 14 and 15. The power supply system 100 according to the modification differs from the power supply system 10 according to the embodiment in that it has a "single startup mode" in addition to the "simultaneous startup mode" and the "priority startup mode." Note that configurations and processes common to the power supply system 10 according to the embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0112] FIG. 14 is a flowchart illustrating the startup process of power supply system 100 according to a modified example.

[0113] 14, the control device 14 determines whether the remaining capacity of the battery 20 is less than a predetermined lower limit. The predetermined lower limit is, for example, a value indicating the lower limit of the normal use range of the battery 20. Here, it is assumed that the remaining capacity of the battery 20 is determined to be less than the predetermined lower limit when, for example, the remaining capacity of the battery 20 is extremely low.

[0114] If it is determined in step S90 that the remaining capacity of the battery 20 is less than the predetermined lower limit (step S90: YES), the control device 14 transitions to the independent startup mode in step S91. The subroutine called in step S91 is shown in FIG.

[0115] FIG. 15 is a flowchart illustrating a subroutine for setting "priority 1 (first priority)" to the FCS 16 in the modified example.

[0116] In step S92, the control device 14 calculates the available startup power Pavbl that can be used to start the FCS 16. The available startup power Pavbl is basically the power that the battery 20 can supply to the FCS 16. In steps S93 and S94, the control device 14 selects only the FCS 16 with the highest temperature within the range of the remaining capacity of the battery 20. In step S95, the control device 14 sets "priority 1 (first priority)" to the selected FCS 16. In step S96, the control device 14 sets "priority 0 (zeroth priority)" to the other FCSs 16 and ends the subroutine.

[0117] While the remaining capacity of the battery 20 is below a predetermined lower limit (step S90 in FIG. 14: YES), the control device 14 repeatedly executes the startup process in the single startup mode until the startup of all FCSs 16 is completed (step S60 in FIG. 2: NO).

[0118] That is, in the independent startup mode, the control device 14 sets "priority 1 (first priority)" to the FCS 16 with the highest temperature. Once startup of the FCS 16 that has been set to "priority 1 (first priority)" is completed, "priority 1 (first priority)" is again set to the FCS 16 with the next highest temperature. In the independent startup mode, unlike the priority startup mode, the same priority (priority order) is not set to multiple FCSs 16. Of the FCSs 16 that have not yet started, the FCS 16 with the highest temperature is started up alone. The output power Pfc of the FCS 16 that has completed startup is used in the startup process of the next FCS 16 to be started up.

[0119] In this way, in the single startup mode, the power supply system 100 according to the modification can start up the FCSs 16 one by one, starting with the FCS 16 with the highest temperature. This allows the power supply system 100 to start up quickly while suppressing power consumption associated with the startup of the FCSs 16.

[0120] In the stand-alone startup mode, the battery 20 may be charged with the available output power Pfc of the FCS 16 that has completed startup. When the remaining capacity of the battery 20 reaches or exceeds the lower limit of the normal use range, the stand-alone startup mode may be switched to the priority startup mode. This allows the power supply system 100 to start up quickly.

[0121] In addition to the above disclosure, the following additional notes are disclosed.

[0122] (Appendix 1) The power supply system (10, 100) of the present disclosure is a power supply system having a secondary battery (20) connected to a load (26), a plurality of fuel cell systems (16) connected to the load and the secondary battery, and a control device (14) that controls the startup of the plurality of fuel cell systems and the supply of power to the load, and further has a remaining capacity acquisition device (14) that acquires the remaining capacity of the secondary battery, and a temperature acquisition device (32) that acquires the temperature of the fuel cell system, and the control device calculates a startup required power (Preq) as the power required to start the fuel cell system, and sets priorities indicating the order of startup for the plurality of fuel cell systems based on the temperature of the fuel cell system, the startup required power, and the remaining capacity of the secondary battery, and starts up the plurality of fuel cell systems according to the priorities.

[0123] With this configuration, the power supply system can reflect the current status of the power supply system and start up the fuel cell system that is most suitable for that status with priority, thereby improving the start-up responsiveness of the power supply system.

[0124] (Appendix 2) In the power supply system described in Appendix 1, when the remaining capacity of the secondary battery is equal to or greater than a predetermined value, the control device may set the same priority for the multiple fuel cell systems and start up the multiple fuel cell systems simultaneously.

[0125] With this configuration, when the secondary battery has sufficient remaining capacity, the power supply system can reflect this situation by assigning the same priority to the multiple fuel cell systems and starting up the multiple fuel cell systems simultaneously, thereby enabling the power supply system to start up quickly.

[0126] (Appendix 3) In the power supply system described in Appendix 1, when the remaining capacity of the secondary battery is less than a predetermined value, the control device may select one or more fuel cell systems with the highest temperature from among the plurality of fuel cell systems that have not yet been started, set a higher priority for the selected fuel cell system than for the other fuel cell systems, and start the selected fuel cell system in preference to the other fuel cell systems.

[0127] With this configuration, when the remaining capacity of the secondary battery is insufficient, the power supply system selects the fuel cell system to start up, taking into account the situation. That is, the number of fuel cells to start up can be limited, and fuel cell systems with higher temperatures can be started up first. This allows the power supply system to start up quickly.

[0128] (Appendix 4) In the power supply system described in Appendix 3, when two or more fuel cell systems are selected from the plurality of fuel cell systems that have not yet been started, the control device may set the same priority to the two or more selected fuel cell systems and start the two or more selected fuel cell systems in preference to the other fuel cell systems, provided that the total value of the required start-up power of the two or more selected fuel cell systems is less than the remaining capacity of the secondary battery.

[0129] With this configuration, even when the remaining capacity of the secondary battery is insufficient, the power supply system allows multiple fuel cell systems to be started simultaneously within the remaining capacity of the secondary battery. In other words, the number of fuel cell systems that can be started can be increased within the remaining capacity of the secondary battery. This allows the power supply system to be started up quickly.

[0130] (Appendix 5) In the power supply system described in Appendix 3, after one or more of the plurality of fuel cell systems have completed startup, the control device may set the priority based on the temperature of the fuel cell system, the power required for startup, the remaining capacity of the secondary battery, and the output power of the fuel cell system that has completed startup, and start up the fuel cell system that has not yet started using at least one of the power supplied from the secondary battery and the output power of the fuel cell system that has completed startup.

[0131] With this configuration, when one or more fuel cell systems have completed startup, the power supply system can start up any fuel cell systems that have not yet started, reflecting the output power of the fuel cell systems that have completed startup, thereby enabling the power supply system to start up quickly.

[0132] (Appendix 6) In the power supply system described in Appendix 1, when the remaining capacity of the secondary battery is smaller than a predetermined value indicating the lower limit of the secondary battery's normal usage range, the control device may select a first fuel cell system with the highest temperature from among the plurality of fuel cell systems that have not been started, set a higher priority for the selected first fuel cell system than for the other fuel cell systems, start up only the selected first fuel cell system using power supplied from the secondary battery, and after the first fuel cell system has completed start-up, select a second fuel cell system with the second highest temperature from among the plurality of fuel cell systems that have not been started, and start up the second fuel cell system using the output power of the first fuel cell system.

[0133] With this configuration, when the remaining capacity of the secondary battery is lower than the normal usage range, the power supply system reflects this situation and starts up only the fuel cell systems that are expected to be able to start up in a short time. The power supply system also starts up the other fuel cell systems using the power generated by the fuel cell system that has completed startup. This allows the power supply system to quickly begin startup while suppressing the power consumption required for startup of the fuel cell systems.

[0134] (Appendix 7) In the power supply system described in Appendix 1, the control device may start supplying power to the load when the total amount of power that can be output by the fuel cell systems that have already started up becomes equal to or greater than the amount of power required by the load.

[0135] With this configuration, the power supply system can quickly start supplying power to the load without waiting for all fuel cell systems to finish starting up, thereby improving the startup responsiveness of the power supply system.

[0136] (Appendix 8) In the power supply system described in Supplementary Note 1, the control device may exclude a fuel cell system in which a failure has occurred from targets for which the priority is set.

[0137] With this configuration, the power supply system does not have to wait for the fuel cell system that cannot be started to complete startup, and can therefore quickly start supplying power to the load.

[0138] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [Explanation of symbols]

[0139] 10, 100... Power supply system 14... Control device (remaining capacity acquisition device) 16...FCS (Fuel Cell System) 20...Battery (Secondary Battery) 26...Motor (load) 32...Temperature sensor (temperature acquisition device) Pall: Available output power of the power supply system Pavbl: Available power for startup Pfc: Available output power of FCS Preq: Required power for startup

Claims

1. a secondary battery connected to a load; a plurality of fuel cell systems connected to the load and the secondary battery; a control device that controls the activation of the plurality of fuel cell systems and the supply of power to the load; A power supply system having: moreover, a remaining capacity acquisition device for acquiring a remaining capacity of the secondary battery; a temperature acquisition device for acquiring a temperature of the fuel cell system; and The control device calculating a required startup power as power required to start the fuel cell system; setting priorities indicating an order of startup for the plurality of fuel cell systems according to the temperatures of the fuel cell systems, the required startup power, and the remaining capacity of the secondary batteries; activating the plurality of fuel cell systems in accordance with the priority; Power supply system.

2. 2. The power supply system according to claim 1, The control device If the remaining capacity of the secondary battery is equal to or greater than a predetermined value, the same priority is set for the plurality of fuel cell systems; The plurality of fuel cell systems are started up simultaneously. Power supply system.

3. 2. The power supply system according to claim 1, The control device If the remaining capacity of the secondary battery is less than a predetermined value, one or more fuel cell systems having a high temperature are selected from among the fuel cell systems that have not yet been started, setting a higher priority for the selected fuel cell system than for the other fuel cell systems; The selected fuel cell system is started up in preference to the other fuel cell systems. Power supply system.

4. 4. The power supply system according to claim 3, The control device When two or more fuel cell systems are selected from the fuel cell systems that have not yet been started among the plurality of fuel cell systems, setting the same priority to the selected two or more fuel cell systems on the condition that the total value of the required start-up power of the selected two or more fuel cell systems is less than the remaining capacity of the secondary battery; The two or more selected fuel cell systems are started up in preference to the other fuel cell systems. Power supply system.

5. 4. The power supply system according to claim 3, The control device After one or more of the fuel cell systems among the plurality of fuel cell systems has completed startup, setting the priority in accordance with the temperature of the fuel cell system, the required power for startup, the remaining capacity of the secondary battery, and the output power of the fuel cell system that has completed startup; The fuel cell system that has not yet been started is started up using at least one of the power supplied from the secondary battery and the output power of the fuel cell system that has completed starting up. Power supply system.

6. 2. The power supply system according to claim 1, The control device If the remaining capacity of the secondary battery is smaller than a predetermined value indicating a lower limit of a normal use range of the secondary battery, a first fuel cell system having the highest temperature is selected from the plurality of fuel cell systems that have not yet been started; setting a higher priority for the selected first fuel cell system than for the other fuel cell systems; starting only the selected first fuel cell system with the power supplied from the secondary battery; After the first fuel cell system has completed startup, a second fuel cell system having the second highest temperature is selected from among the plurality of fuel cell systems that have not yet started up; The second fuel cell system is started up by the output power of the first fuel cell system. Power supply system.

7. 2. The power supply system according to claim 1, The control device When the total power that the activated fuel cell systems can output is equal to or greater than the power required by the load, the power supply to the load is started. Power supply system.

8. 2. The power supply system according to claim 1, The control device The fuel cell system in which the failure occurred is excluded from the targets for setting the priority. Power supply system.

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