Power supply system

Abstract

Improves the startup responsiveness of the power system. [Solution] The control device 14 calculates the startup power Preq, which is the power required to start up the fuel cell system (FCS) 16. The control device 14 sets a priority order for starting up multiple FCS 16s according to the temperature of the FCS 16, the startup power Preq, and the remaining capacity of the battery 20, and starts up the multiple FCS 16s according to the priority order.

Description

Technical Field

[0001] This invention relates to a power supply system.

Background Art

[0002] In recent years, in order for more people to have access to affordable, reliable, sustainable, and advanced energy, research and development on fuel cells that contribute to energy efficiency have been carried out.

[0003] Japanese Patent Application Laid-Open No. 2017-126441 discloses a power supply system having a plurality of fuel cell systems. This power supply system selects one fuel cell system with the highest temperature from the non-operating fuel cell systems and starts the selected fuel cell system first.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

[0006] The object of this invention is to solve the above-mentioned problems.

Means for Solving the Problems

[0007] One aspect of this invention is a power supply system comprising: 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 for controlling the startup of the plurality of fuel cell systems and the supply of power to the load, further comprising: a remaining capacity acquisition device for acquiring the remaining capacity of the secondary battery; and a temperature acquisition device for acquiring the temperature of the fuel cell systems, wherein the control device calculates the startup power required to start the fuel cell systems, sets a priority order indicating the startup order for the plurality of fuel cell systems according to the temperature of the fuel cell systems, the startup power required, and the remaining capacity of the secondary battery, and starts the plurality of fuel cell systems according to the priority order. [Effects of the Invention]

[0008] According to this invention, the startup responsiveness of the power supply system can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a block diagram showing an example of the configuration of a power supply system according to an embodiment. [Figure 2] Figure 2 is a flowchart illustrating the startup process of the power supply system shown in Figure 1. [Figure 3] Figure 3 is a flowchart illustrating a subroutine for calculating the number of start-upable fuel cell systems (FCS). [Figure 4] Figure 4 is a flowchart illustrating the subroutine used to set the FCS startup mode. [Figure 5] Figure 5 is a flowchart illustrating the subroutine used to calculate the power output value of the power supply system. [Figure 6] Figure 6 is a flowchart illustrating the subroutine for setting priority in the simultaneous startup mode. [Figure 7] Figure 7 is a flowchart illustrating the subroutine that instructs the FCS to start up. [Figure 8] Figure 8 is a flowchart illustrating the subroutine used to determine when the power supply system has finished starting up. [Figure 9] Figure 9 is a flowchart illustrating the subroutine for setting priority in priority startup mode. [Figure 10] Figure 10 is a flowchart illustrating a subroutine for setting priorities for one or more FCSs. [Figure 11] Figure 11 is an explanatory diagram illustrating an example of the relationship between FCS temperature and the power required to start up the FCS. [Figure 12] Figure 12A is an explanatory diagram showing an example of the timing of FCS startup completion and the progression of power available for FCS startup, as shown in Figure 11. Figure 12B is an explanatory diagram showing an example of the priority set for FCS. [Figure 13] Figure 13 is a timing chart showing an example of the timing of the completion of FCS startup and power supply system startup. [Figure 14] Figure 14 is a flowchart illustrating the startup process of a modified power supply system. [Figure 15] Figure 15 is a flowchart illustrating a subroutine for setting a priority for a single FCS. [Modes for carrying out the invention]

[0010] Figure 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 described as a fuel cell vehicle 12 (FCV) that is propelled (runs) by the electricity generated by a fuel cell. However, the power supply system 10 is not limited to a fuel cell vehicle 12. The power supply system 10 may be a mobile body other than a vehicle, such as a ship, aircraft, or robot. The power supply system 10 may also be a stationary power supply 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), 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 a plurality of FCSs 16. The FCS 16 includes a fuel cell stack and various devices used for the operation of the fuel cell stack.

[0013] The fuel cell stack includes a plurality of fuel cells (power generation cells). The plurality of fuel cells generate electricity by an electrochemical reaction between a fuel gas and an 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 loads such as the motor 26 and is also used to charge the battery 20.

[0014] The FCS 16 includes, as devices used for the operation of the fuel cell stack, an auxiliary machine (not shown) and a temperature sensor 32. [[ID=|13]]

[0015] The auxiliary machine supplies a fuel gas and an oxidant gas to the fuel cell stack. The auxiliary machine includes a hydrogen tank, an air pump, a refrigerant system, valves, pipes, and other equipment associated therewith. Note that the FCS 16 may include a heater for warming the fuel cell stack as the auxiliary machine.

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

[0017] The FCS16 is equipped with various sensors, including current sensors and voltage sensors (not shown), and has a function to calculate the power that the FCS16 can currently output. The FCS16 outputs the calculated value of the currently outputtable power to the control device 14 (in the following description, the power that the FCS16 can currently output will be referred to as the outputtable power Pfc). The FCS16 also has a function to detect abnormalities within the FCS16. The FCS16 outputs a signal to the control device 14 indicating whether or not there is an abnormality in the FCS16.

[0018] The FCVCU18 is a boost converter that increases the voltage of the power output by the FCS16 and outputs it to the BATVCU22. This power supply system 10 has one FCVCU18 for each FCS16.

[0019] The power supply system 10 comprises one or more batteries 20. The batteries 20 are rechargeable batteries capable of charging and discharging power. The batteries 20 supply power to loads such as motors 26 and are charged by the power output from the FCS 16 and the regenerative power of the motors 26.

[0020] The battery 20 is equipped with various sensors, including a current sensor and a voltage sensor (not shown). The measurements 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. In other words, the control device 14 functions as a device for acquiring the remaining capacity of the battery 20. However, the means for acquiring the remaining capacity of the battery 20 are not limited to this, and various known means may be used.

[0021] BATVCU22 is a buck-boost converter that boosts and adjusts the voltage of the power output from battery 20 and FCVCU18, and outputs it to PDU24. BATVCU22 boosts or bucks the power output from FCVCU18 to a voltage suitable for charging battery 20 and outputs it to battery 20.

[0022] The PDU24 is an inverter that converts the input power into a frequency and voltage suitable for the rotational speed and torque of the motor 26 and outputs it to the motor 26.

[0023] Motor 26 is an electric motor that operates using the input power and converts that power into driving force (rotational force) for output. Motor 26 is an example of a load that requests power supply from FCS16.

[0024] T / M28 is a transmission that transmits the rotational force output by motor 26 to wheels 30, adjusting the torque.

[0025] The control device 14 is a computer that controls the power supply system 10. The control device 14 can manage all the 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, an arithmetic unit (processing unit) and a storage unit.

[0027] The arithmetic unit may be composed of a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). In other words, the arithmetic unit may be composed of processing circuitry.

[0028] The arithmetic unit includes functional units such as a determination unit, a battery remaining 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 arithmetic unit executing computer-executable commands (programs) stored in the memory unit.

[0029] At least a portion of the arithmetic unit may be implemented by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). Alternatively, at least a portion of the arithmetic unit may be composed of an electronic circuit including discrete devices.

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

[0031] <Explanation of operations related to the startup process of the power supply system 10> The power supply system 10 is basically configured as described above. Next, the operation related to the startup process of the power supply system 10 will be explained with reference to the flowchart in Figure 2.

[0032] Figure 2 is a flowchart illustrating the startup process of the power supply system 10 shown in Figure 1. When the control device 14 receives a startup instruction, such as a user's instruction to start driving the fuel cell vehicle 12, it starts the startup process of the power supply system 10.

[0033] In step S10, the control device 14 calculates the number of FCS16s that can be started (hereinafter, the number of FCS16s is referred to as the base or system number). The subroutine called in step S10 is shown in Figure 3.

[0034] Figure 3 is a flowchart illustrating a subroutine for calculating the number of activatable FCS16s. In step S11 of Figure 3, the control device 14 obtains the number of FCS16s installed in the power supply system 10. The control device 14 may, for example, obtain the number of installed FCS16s that have been previously stored in the storage unit.

[0035] In step S12, the control device 14 obtains the number of faulty FCS16s. The control device 14 queries each FCS16 for fault status, for example. The control device 14 may obtain the number of faulty FCS16s based on the number of abnormal signals received from each FCS16. An FCS16 abnormality means that the FCS16 cannot start up properly, and includes, for example, failure of the air pump or valves, cross-leakage in the fuel cell stack, etc.

[0036] In step S13, the control device 14 subtracts the number of faulty FCS16 from the number of installed FCS16 to calculate the number of FCS16 that can be started. At this time, the control device 14 can obtain the address of each FCS16 and identify the FCS16 that can be started normally.

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

[0038] Returning to the process shown in Figure 2, the control device 14 sets the startup mode of the FCS 16 in step S20. The subroutine called in step S20 is shown in Figure 4.

[0039] Figure 4 is a flowchart illustrating the subroutine for setting the startup mode of the FCS16. In step S21 of Figure 4, the control device 14 obtains the remaining capacity of the battery 20. The control device 14 may obtain the remaining capacity of the battery 20 based on measured values ​​from current sensors (not shown) and voltage sensors (not shown) provided on the battery 20, and a map stored in the memory unit.

[0040] In step S22, the control device 14 obtains the temperature of the FCS 16 from the temperature sensor 32.

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

[0042] In step S24, the control device 14 calculates the power output value that the power supply system 10 can output. The subroutine called in step S24 is shown in Figure 5.

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

[0044] Furthermore, the output power Pfc of an inactive FCS16 is 0 (zero). Therefore, in the initial state, the output power Pall of the power supply system 10 is also 0 (zero).

[0045] Returning to the process shown in Figure 4, in step S25, the control device 14 determines whether all FCS 16 can be started simultaneously. The control device 14 may determine whether simultaneous startup is possible based, for example, on the remaining capacity of the battery 20 and the required power Preq for starting the FCS 16.

[0046] If the battery 20 has sufficient remaining capacity and can supply the required power Preq to all FCS 16, the control device 14 may determine that all FCS 16 can be started simultaneously (step S25: YES). In this case, the control device 14 switches to simultaneous startup mode in step S26. The subroutine called in step S26 is shown in Figure 6.

[0047] Figure 6 is a flowchart illustrating the subroutine for setting priority in simultaneous startup mode. Here, the priority of an FCS16 refers to the order in which the FCS16s are started. That is, an FCS16 with a higher priority will be started earlier and preferentially than other FCS16s. In the following explanation, the term "priority" may be used to indicate the order of startup, but "priority" and "priority" are used interchangeably.

[0048] The power supply system 10 according to this embodiment allows multiple FCS 16 to be assigned the same priority. For example, if multiple FCS 16 are assigned the same priority, they will be started up simultaneously.

[0049] When the system switches to simultaneous startup mode, the control device 14 sets "priority 1" for all FCS 16 in step S261 of Figure 6. Priority 1 means "priority number 1". In other words, in simultaneous startup mode, all FCS 16 can be started simultaneously.

[0050] Returning to step S25 in Figure 4, for example, if the remaining capacity of battery 20 is low, battery 20 cannot supply the necessary power Preq to all FCS 16. The control device 14 may determine that it is not possible to start all FCS 16 simultaneously (step S25: NO).

[0051] In this case, the control device 14 switches to priority start mode in step S27. In priority start mode, one or more FCS 16s are selected based on temperature, and the selected FCS 16s are started sequentially in priority to the other FCS 16s. Details of priority start mode will be described later.

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

[0053] Figure 7 is a flowchart illustrating the subroutine that instructs the FCS16 to start up. The control device 14 instructs the FCS16 to start up according to priority.

[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 above a predetermined value (for example, 80 degrees Celsius or higher). Here, the explanation continues assuming that the FCS 16 assigned "priority 1 (first priority)" has not yet started up (step S31: NO).

[0055] In step S32, the control device 14 issues a start command to the FCS 16 that has been assigned "priority 1 (first priority)". Here, it is assumed that all FCS 16s have "priority 1" set, so all FCS 16s that can start up normally begin the start process simultaneously.

[0056] Returning to the process shown in Figure 2, the control device 14 calculates the output power Pall of the power supply system 10 in step S40. The subroutine called in step S40 is shown in Figure 5.

[0057] In step S41, the control device 14 uses the sum of the output power Pfc of the FCS 16 that have finished starting up as the output power Pall of the power supply system 10. Here, since each FCS 16 has just started up, the output power Pfc is 0, and the output power Pall of the power supply system 10 is 0.

[0058] Returning to the process shown in Figure 2, the control device 14 determines in step S50 whether the entire power supply system 10 has finished starting up. The subroutine called in step S50 is shown in Figure 8.

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

[0060] If the startup of all FCS16 has not been completed (step S51: NO) and the startup waiting time has not elapsed (step S52: NO), then in step S55, the status flag of the power system 10 is set to the "startup incomplete flag".

[0061] In this case, the process returns to the one shown in Figure 2, and it is determined again in step S60 that the startup of all FCS16 has not been completed (step S60: NO). The process returns to step S10, and the FCS16 startup process is repeatedly executed until the startup of all FCS16 is completed.

[0062] In step S51 of Figure 8, if it is determined that all FCS16 have started up (step S51: YES), then in step S54, the "startup complete flag" is set in the status flag of the power system 10.

[0063] In this case, the process returns to the one shown in Figure 2, and in step S60, it is determined again that the startup of all FCS16 has been completed (step S60: YES), and the startup process of the power supply system 10 is terminated. The power supply system 10 starts up and can begin supplying power to the load.

[0064] In step S51 of Figure 8, even if not all FCS16 have completed startup (step S51: NO), if the startup waiting time has elapsed (step S52: YES) and the available power output 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 "startup complete flag" to the status flag of the power supply system 10 (step S54).

[0065] In this case, the power supply system 10 starts up and may begin supplying power to the load using the output power Pfc of the started FCS 16. Meanwhile, the startup process for the inactive FCS 16 is repeatedly executed until all FCS 16 have started up.

[0066] Thus, the power supply system 10 according to this embodiment can start supplying power to the load within the range of the output power Pfc of the started-up FCS 16 without waiting for all FCS 16 to have finished starting up. In other words, this power supply system 10 can start supplying power more quickly than when it starts supplying power after all FCS 16 have finished starting up.

[0067] <Explanation of Priority Startup Mode> Next, the details of the "priority startup mode" will be explained with reference to Figures 4, 9, and 10. The "priority startup mode" is the mode to which the system is switched if it is determined in step S25 of Figure 4 that simultaneous startup of all FCS16 is not possible. The subroutine called in step S27 of Figure 4 is shown in Figure 9.

[0068] Figure 9 is a flowchart illustrating the subroutine for setting priority in priority startup mode.

[0069] In step S71 of Figure 9, the control device 14 determines whether the startup process for all FCS 16 has been completed. Here, assuming that all FCS 16 have not yet started up, it is determined that the startup process for all FCS 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. Assuming that there is no FCS 16 assigned "first priority", 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)" for one or more FCS 16. The subroutine called in step S73 is shown in Figure 10.

[0072] Figure 10 is a flowchart illustrating a subroutine for setting priority N (the Nth priority) to one or more FCS16s.

[0073] In step S81 of Figure 10, the control device 14 calculates the power available to start the FCS 16. Hereinafter, the power available to start the FCS 16 will be referred to as "startup power Pavbl".

[0074] The available startup power Pavbl is basically the power that the battery 20 can supply to the FCS 16. However, if there is an already started FCS 16, it is preferable that the power that the started FCS 16 can output (output power Pfc) is also used to start the other FCS 16s. That is, the available startup power Pavbl may include the output power Pfc of the started FCS 16.

[0075] In step S82, the control device 14 selects the FCS16 with the highest temperature from among several FCS16 that do not have a priority assigned to them. An FCS16 with a high temperature requires less heating time by the heater, for example, and is therefore expected to consume less power to start up and be able to start up in a short time. In the following explanation, an FCS16 that does not have a priority assigned to it may be referred to as an FCS16 that has not yet acquired a priority.

[0076] For the sake of explanation, the first FCS16 selected in step S82 will be denoted as FCS16-1, and similarly, the Mth selected FCS16 will be denoted as FCS16-M. Here, we will continue the explanation 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 power Pavbl for starting FCS16-1 is equal to or greater than the required power Preq for starting FCS16-1. If the available power Pavbl is equal to or greater than the required power Preq for starting FCS16-1 (step S83: YES), in step S84, the control device 14 sets "priority N (the Nth priority)" for FCS16-1. Here, we will continue the explanation assuming that N=1, that is, the control device 14 sets "priority 1 (the first priority)" for FCS16-1.

[0078] In step S85, the control device 14 subtracts the startup power required for FCS16-1, which is set to "priority 1 (first priority)", from the startup power available Pavbl. The control device 14 sets the value after the subtraction as the new startup power available Pavbl.

[0079] Returning to step S82, the control device 14 selects one of the FCS16-2 with the highest temperature from among the multiple FCS16 for which no priority (priority) has been set.

[0080] In step S83, if the new available startup power Pavbl is greater than or equal to the startup required power Preq of FCS16-2 (step S83: YES), then in step S84, the control device 14 sets "priority 1 (first priority)" for FCS16-2. That is, the control device 14 sets "priority 1 (first priority)" for both FCS16, FCS16-1 and FCS16-2. In step S85, the control device 14 updates the value of the available startup power Pavbl and returns to step S82.

[0081] In this way, steps S82 to S85 are repeatedly executed, provided that the available startup power Pavbl is equal to or greater than the startup power Preq of the FCS16-M. As a result, "priority 1 (first priority)" is set for one FCS16 or two to M FCS16s.

[0082] When the available startup power Pavbl falls below the startup power Preq of the FCS16-M (step S83: NO), it is determined that the remaining capacity of battery 20 is insufficient to meet the startup power Preq of the FCS16-M, and the "priority 1 (first priority)" setting process is terminated.

[0083] Returning to the process shown in Figure 9, the control device 14 sets "Priority 0 (Priority 0)" for all FCS16 other than the FCS16 that was set to "Priority 1 (Priority 1)" in step S74. "Priority 0 (Priority 0)" means that no priority has been acquired, i.e., it is in a state of waiting for priority to be set.

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

[0085] In steps S31 and S32 of Figure 7, the control device 14 issues a start command from FCS16-1 of unit M, which is set to "priority 1 (first priority)", to FCS16-M.

[0086] Returning to the process shown in Figure 2, the control device 14 calls the subroutine shown in Figure 5 in step S40. In step S41 of Figure 5, the control device 14 calculates the output power Pall of the power supply system 10.

[0087] Returning to the process shown in Figure 2, the control device 14 calls the subroutine shown in Figure 8 in step S50. Based on the subroutine shown in Figure 8, the control device 14 determines whether the power supply system 10 has finished starting up. If the predetermined conditions are met (step S53: YES), power supply to the load may be started.

[0088] Regardless of whether power supply to the load has started, the control device 14 repeatedly performs the startup process in priority startup mode until all FCS 16 have finished starting up (step S60: NO).

[0089] In other words, in priority startup mode, when an FCS16 with priority N-1 (priority N-1) set completes startup (step S75 in Figure 9: YES), the control device 14 sets "priority N (priority N)" for one or more FCS16s in step S77.

[0090] The control device 14 repeatedly executes steps S82 to S85 in Figure 10, provided that the available power for startup Pavbl is equal to or greater than the required power for startup Preq of the FCS 16. As a result, one or more FCS 16s are assigned a higher priority (priority order) in order of decreasing temperature, and one or more FCS 16s can start up according to their priority (priority order).

[0091] Thus, in priority startup mode, even when the remaining capacity of the battery 20 is insufficient, the FCS 16 with the highest temperature (one or more) is prioritized for startup within the remaining capacity range of the battery 20, allowing the power system 10 to start up quickly.

[0092] <Example of startup process using priority startup mode> Next, an example of the startup process using the priority startup mode will be explained in chronological order with reference to Figures 11 and 12.

[0093] Figure 11 is an explanatory diagram illustrating an example of the relationship between the temperature of four FCS16 units and the startup power Preq [kW] required to start each FCS16 unit. To distinguish the four FCS16 units from one another, they are referred to as FCS#1, FCS#2, FCS#3, and FCS#4 in Figure 11. As shown in the second and third rows of Figure 11, FCS16 units with higher temperatures have lower startup power Preq, while FCS16 units with lower temperatures have higher startup power Preq.

[0094] The fourth row of Figure 11 shows the power [kW] that the battery 20 can output, and the fifth row shows the power Pfc [kW] that each FCS 16 can output after startup. The sum of the power that the battery 20 can output and the power Pfc of each FCS 16 corresponds to the startup power Pavbl [kW] calculated in step S81 of Figure 10. That is, the startup power Pavbl is the power that the power supply system 10 can use to start up the FCS 16 that have not been started.

[0095] Figure 12A is an explanatory diagram showing an example of the startup completion timing of FCS16 (FCS#1 to FCS#4) shown in Figure 11 and the progression of the startup-available power Pavbl. Figure 12B is an explanatory diagram showing an example of the priority (priority setting) set for each FCS16.

[0096] At time t0 in Figures 12A and 12B, the startup process for the power supply system 10 begins. At time t0, none of the four FCS 16 units are started.

[0097] As shown in Figure 11, the output power of battery 20 (15kW) is less than the sum of the required starting power Preq for the four FCS 16 (10kW + 15kW + 15kW + 20kW = 60kW). In other words, battery 20 cannot supply the power necessary to start all four FCS 16 simultaneously (step S25 in Figure 4: NO). For this reason, the control device 14 switches to priority start mode.

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

[0099] The value obtained by subtracting the required power Preq (10kW) for starting FCS#1 from the output power (15kW) of battery 20 is 5kW. This 5kW is less than the required power Preq (15kW) for starting 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. The control device 14 sets "priority 0 (priority 0th)" for the three units other than FCS#1 and instructs FCS#1 to start up.

[0100] At time t1, once the startup of FCS#1 is complete, the available startup power Pavbl increases by the amount of the available output power Pfc (10kW) of FCS#1, to 25kW. The power system 10 can use the new available startup power Pavbl to meet the startup requirement Preq (15kW) of FCS#2 (step S83: YES). Priority 2 is set for FCS#2, and the startup of FCS#2 is initiated.

[0101] At time t2, once the startup of FCS#2 is complete, the available startup power Pavbl increases further by the amount of the available output power Pfc (10kW) of FCS#2, reaching 35kW. The power system 10 can use the new available startup power Pavbl to meet the startup requirements Preq (15kW) for FCS#3 and FCS#4 (Step S83: YES). Priority 3 is set for FCS#3 and FCS#4, and the startup of FCS#3 and FCS#4 is initiated.

[0102] At time t3, once FCS#3 and FCS#4 have finished starting up, the available power Pavbl will increase by the amount of the available power Pfc (10kW) of FCS#3 and the available power Pfc (10kW) of FCS#4, reaching 55kW. Once all four FCS16 have finished starting up (step S60: YES), the control device 14 will terminate the startup process of the power supply system 10.

[0103] <Example of power system startup completion determination process> Next, referring to Figure 13, an example of the process by which the control device 14 determines that the power supply system 10 has finished starting up will be explained in chronological order.

[0104] Figure 13 is a timing chart showing an example of the timing of the completion of startup of the four FCS16 units and the power supply system 10. To distinguish the four FCS16 units from each other, they are named FCS#5, FCS#6, FCS#7, and FCS#8 in Figure 13.

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

[0106] At time t5, the startup waiting time has elapsed. At time t5, three FCS16 units, FCS#5, FCS#7, and FCS#6, have completed startup, while FCS#8 has not yet started.

[0107] The control device 14 calculates a total value by summing the output power Pfc [kW] of the three FCS#5, FCS#7, and FCS#6, which have completed startup (step S41 in Figure 5). This total value corresponds to the output power Pall [kW] that the power supply system 10 can output. If the output power Pall of the power supply system 10 is equal to or greater than the load's required power (step S53 in Figure 8: YES), the control device 14 sets the "startup complete flag" to the status flag of the power supply system 10.

[0108] When the startup completion flag is set, the control device 14 can determine that the startup process for 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 power Pall. In other words, the control device 14 relaxes the output limit of the power supply system 10. As a result, the power supply system 10 can start supplying power to the load. However, the startup process for the inactive FCS#8 continues.

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

[0110] The temperature and ease of heating of the FCS16 may vary depending on its installation location. However, the power supply system 10 according to this embodiment can start supplying power to the load when the available power Pall reaches the load's required power. Power supply can be started quickly without waiting for all FCS16 to have finished starting up.

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

[0112] Figure 14 is a flowchart illustrating the startup process of the power supply system 100 in a modified example.

[0113] In step S90 of Figure 14, the control device 14 determines whether the remaining capacity of the battery 20 is below a predetermined lower limit. The predetermined lower limit is, for example, a value indicating the lower limit of the normal operating range of the battery 20. In this case, it is assumed that the remaining capacity of the battery 20 is determined to be below the predetermined lower limit, for example, when the remaining capacity of the battery 20 is extremely low.

[0114] In step S90, if it is determined that the remaining capacity of the battery 20 is below a predetermined lower limit (step S90: YES), in step S91, the control device 14 switches to standalone startup mode. The subroutine called in step S91 is shown in Figure 15.

[0115] Figure 15 is a flowchart illustrating the subroutine used to set "Priority 1 (First Priority)" to FCS16 in a modified example.

[0116] In step S92, the control unit 14 calculates the available power Pavbl that can be used to start the FCS 16. The available power Pavbl is basically the power that the battery 20 can supply to the FCS 16. In steps S93 and S94, the control unit 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 unit 14 sets "priority 1 (priority 1)" for the selected FCS 16. In step S96, the control unit 14 sets "priority 0 (priority 0)" for the other FCS 16 and terminates the subroutine.

[0117] As long as the remaining capacity of the battery 20 is below a predetermined lower limit (step S90 in Figure 14: YES), the control device 14 repeatedly performs the startup process in single-unit startup mode until the startup of all FCS 16 is completed (step S60 in Figure 2: NO).

[0118] In other words, in single-start mode, the control device 14 sets "priority 1 (first priority)" for the FCS 16 with the highest temperature. Once the startup of the FCS 16 with "priority 1 (first priority)" is complete, "priority 1 (first priority)" is again set for the FCS 16 with the next highest temperature. In single-start mode, unlike in priority start mode, the same priority (priority) is not set for multiple FCS 16s. The FCS 16 with the highest temperature among the unstarted FCS 16s is started independently. The output power Pfc of the FCS 16 that has completed startup is used for the startup process of the next FCS 16 to be started.

[0119] In this modified power supply system 100, in standalone startup mode, the FCS 16s can be started one by one, starting with the one with the highest temperature. This allows the power supply system 100 to start up quickly while suppressing the power consumption associated with the startup of the FCS 16.

[0120] In addition, in standalone startup mode, the output power Pfc of the FCS16, once startup is complete, may be used to charge the battery 20. When the remaining capacity of the battery 20 exceeds the lower limit of the normal operating range, the system may switch from standalone startup mode to priority startup mode. This allows the power supply system 100 to start up quickly.

[0121] In addition to the disclosures mentioned above, the following further notes are made:

[0122] (Note 1) The power supply system (10, 100) of the present disclosure comprises 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 starting of the plurality of fuel cell systems and the supply of power to the load, further comprising a remaining capacity acquisition device (14) for acquiring the remaining capacity of the secondary battery and a temperature acquisition device (32) for acquiring the temperature of the fuel cell systems, wherein the control device calculates the required starting power (Preq) as the power necessary to start the fuel cell systems, sets a priority indicating the order in which to start the plurality of fuel cell systems according to the temperature of the fuel cell systems, the required starting power and the remaining capacity of the secondary battery, and starts the plurality of fuel cell systems according to the priority.

[0123] With this configuration, the power supply system can reflect its current status and prioritize starting up the fuel cell system best suited to that situation. This improves the power supply system's startup responsiveness.

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

[0125] With this configuration, when the secondary battery has sufficient remaining capacity, the power system can reflect this situation by setting the same priority for multiple fuel cell systems and starting them all simultaneously. This allows the power system to start up quickly.

[0126] (Note 3) In the power supply system described in Appendix 1, if 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 a higher temperature from among the multiple fuel cell systems that have not 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 priority to the other fuel cell systems.

[0127] With this configuration, when the remaining capacity of the secondary battery is insufficient, the power system selects which fuel cell systems to start, reflecting the situation. That is, it can limit the number of fuel cell systems to start and prioritize starting fuel cell systems with higher temperatures. This allows the power system to start up quickly.

[0128] (Note 4) In the power supply system described in Appendix 3, if two or more fuel cell systems are selected from among the multiple fuel cell systems that have not been started, the control device may set the same priority for the two or more selected fuel cell systems and start them up in priority to the other fuel cell systems, provided that the total value of the power required to start 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 system allows multiple fuel cell systems to be started simultaneously, within the limits of the remaining capacity of the secondary battery. In other words, the number of fuel cell systems to be started can be increased within the limits of the remaining capacity of the secondary battery. This allows the power system to be started up quickly.

[0130] (Note 5) In the power supply system described in Appendix 3, after one or more of the plurality of fuel cell systems have completed starting up, the control device may set the priority according to the temperature of the fuel cell system, the required starting power, the remaining capacity of the secondary battery, and the output power of the fuel cell system that has completed starting up, and start up the unstarted fuel cell system 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.

[0131] With this configuration, once one or more fuel cell systems have completed startup, the power supply system can start any unstarted fuel cell systems by reflecting the output power of the started-up systems. This allows the power supply system to start up quickly.

[0132] (Note 6) In the power supply system described in Appendix 1, if the remaining capacity of the secondary battery is less than a predetermined value indicating the lower limit of the normal operating range of the secondary battery, the control device may select the first fuel cell system with the highest temperature from among the multiple unstarted fuel cell systems, set a higher priority for the selected first fuel cell system than for the other fuel cell systems, start only the selected first fuel cell system with the power supplied from the secondary battery, and after the first fuel cell system has finished starting up, select the second fuel cell system with the second highest temperature from among the multiple unstarted fuel cell systems, and start the second fuel cell system with 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 operating range, the power supply system reflects this situation and starts only the fuel cell systems that are expected to start up quickly. Furthermore, the power supply system uses the power generated by the fuel cell systems that have finished starting up to start up the other fuel cell systems. This allows the power supply system to start up quickly while suppressing the power consumption associated with starting up the fuel cell systems.

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

[0135] With this configuration, the power supply system can quickly begin supplying power to the load without waiting for all fuel cell systems to have finished starting up. This improves the startup responsiveness of the power supply system.

[0136] (Note 8) In the power supply system described in Appendix 1, the control device may exclude the fuel cell system that has experienced a failure from the list of targets for setting the priority.

[0137] With this configuration, the power supply system can quickly begin supplying power to the load without having to wait for the fuel cell system, which may not be able to start up, to complete its startup.

[0138] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the intent of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above. [Explanation of Symbols]

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

Claims

1. A secondary battery connected to a load, Multiple fuel cell systems connected to the aforementioned load and the aforementioned secondary battery, A control device that controls the startup 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 the remaining capacity of the secondary battery, A temperature acquisition device for acquiring the temperature of the fuel cell system, It has, The control device is The startup power required to start the aforementioned fuel cell system is calculated, A priority order indicating the startup sequence is set for the plurality of fuel cell systems according to the temperature of the fuel cell system, the required startup power, and the remaining capacity of the secondary battery. The plurality of fuel cell systems are started according to the priority order. Power supply system.

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

3. In the power supply system according to claim 1, The control device is If the remaining capacity of the secondary battery is less than a predetermined value, one or more fuel cell systems with a high temperature are selected from among the multiple fuel cell systems that have not been started. A higher priority is set for the selected fuel cell system than for the other fuel cell systems. The selected fuel cell system is started in priority over the other fuel cell systems. Power supply system.

4. In the power supply system according to claim 3, The control device is If two or more fuel cell systems are selected from among the multiple fuel cell systems that have not been started, Provided that the sum of the startup power required for two or more selected fuel cell systems is less than the remaining capacity of the secondary battery, the same priority is set for the two or more selected fuel cell systems. To start up two or more selected fuel cell systems in priority to other fuel cell systems. Power supply system.

5. In the power supply system according to claim 3, The control device is After one or more of the aforementioned fuel cell systems have completed startup, The priority is set according to 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 after startup is complete. The power supplied from the secondary battery and the output power of the fuel cell system after it has started up are used to start the fuel cell system that has not yet started up. Power supply system.

6. In the power supply system according to claim 1, The control device is If the remaining capacity of the secondary battery is less than a predetermined value indicating the lower limit of the normal operating range of the secondary battery, the first fuel cell system with the highest temperature is selected from among the multiple unactivated fuel cell systems. A higher priority is set for the selected first fuel cell system than for the other fuel cell systems. The power supplied from the secondary battery activates only the selected first fuel cell system. After the first fuel cell system has completed startup, a second fuel cell system with the second highest temperature is selected from among the multiple fuel cell systems that have not yet started up. The output power of the first fuel cell system is used to start the second fuel cell system. Power supply system.

7. In the power supply system according to claim 1, The control device is When the total power output of the started-up fuel cell system exceeds the power value required by the load, power supply to the load is initiated. Power supply system.

8. In the power supply system according to claim 1, The control device is The fuel cell system that has experienced a malfunction will be excluded from the list of systems for which priority is set. Power supply system.

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