Fuel cell system, control device, working machine, control method

Abstract

To provide a technology which adequately suppresses deterioration of both of a fuel cell and storage battery.SOLUTION: A fuel cell system 100 includes: a fuel cell module 40 which can output power to an actuator 120, an auxiliary load 130, and a storage battery 140 connected so as to supply power to the actuator 120 and auxiliary load 130; and a control unit 30 which controls output of the fuel cell module 40 by considering both output fluctuation of the fuel cell module 40 and a storage state of the storage battery 140.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a fuel cell system and the like. [Background technology]

[0002] For example, when a load device is driven by power from either a fuel cell (FC) or a storage battery that can be charged with fuel cell power, a technique is known for suppressing deterioration of the fuel cell or the storage battery (see, for example, Patent Documents 1 and 2).

[0003] Patent Document 1 discloses that when the SOC of the storage battery is equal to or lower than a relatively low predetermined value, the storage battery is charged by power generation from the fuel cell, and when the SOC of the storage battery is higher than a relatively high predetermined value, the charging of the storage battery by power generation from the fuel cell is stopped. This makes it possible to prevent the storage battery from being overcharged or overdischarged, and to prevent deterioration of the storage battery.

[0004] Patent Document 2 discloses that when the fuel cell supplies generated power to a load device in response to the output load request from the load device, the number of times the output request fluctuates is counted, and if the number of times is relatively large, a catalyst recovery process is carried out, thereby suppressing the deterioration of the fuel cell due to catalyst elution. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-157050 A [Patent Document 2] JP 2009-259526 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, for example, in the above-mentioned Patent Documents 1 and 2, the deterioration of the fuel cell and the storage battery are dealt with separately, so when considering the deterioration of both the fuel cell and the storage battery, there is room for improvement in the method of dealing with the deterioration.

[0007] In view of the above problems, an object of the present invention is to provide a technique capable of more appropriately suppressing the deterioration of both a fuel cell and a storage battery. [Means for solving the problem]

[0008] In order to achieve the above object, in one embodiment of the present disclosure, a fuel cell capable of outputting electric power to a load device and a storage battery connected to the load device so as to be able to supply electric power to the load device; a control device that controls power generation of the fuel cell in consideration of both an output fluctuation of the fuel cell and a charge state of the storage battery; A fuel cell system is provided.

[0009] In another embodiment of the present disclosure, A control device for controlling power generation of a fuel cell capable of outputting electric power to a load device and a storage battery connected to the load device so as to be able to supply electric power, controlling power generation of the fuel cell in consideration of both output fluctuation of the fuel cell and the charge state of the storage battery; A controller is provided.

[0010] In still another embodiment of the present disclosure, an electric motor that drives the actuator; A storage battery connected to the electric motor so as to be able to supply power thereto; a fuel cell capable of outputting electric power to the electric motor and the storage battery; a control device that controls power generation of the fuel cell in consideration of both an output fluctuation of the fuel cell and a charge state of the storage battery; A work machine is provided.

[0011] In still another embodiment of the present disclosure, A control method for controlling power generation of a fuel cell capable of outputting electric power to a load device and a storage battery connected to the load device so as to be able to supply electric power thereto, comprising: controlling power generation of the fuel cell in consideration of both output fluctuation of the fuel cell and the charge state of the storage battery; A control method is provided. Effect of the Invention

[0012] According to the above-described embodiment, it is possible to more appropriately suppress the deterioration of both the fuel cell and the storage battery. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing a configuration of an example of a work machine. [Diagram 2] FIG. 4 is a state transition diagram showing an example of transition of an operation mode of a work machine. [Diagram 3] 4 is a flowchart showing an outline of a first example of processing relating to operation control of a work machine. [Figure 4] 4 is a flowchart showing an outline of a first example of processing relating to operation control of a work machine. [Diagram 5] 4 is a flowchart showing an outline of a first example of processing relating to operation control of a work machine. [Figure 6] 4 is a time chart showing a first example of time variations in the output of a fuel cell module and the charge rate of a storage battery. [Figure 7] 6 is a time chart showing a second example of changes over time in the output of the fuel cell module and the charge rate of the storage battery. [Figure 8] 5 is a flowchart showing an outline of a second example of processing relating to operation control of a work machine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment will be described with reference to the drawings.

[0015] [Example of work machinery] An example of a work machine 1 according to this embodiment will be described with reference to FIG.

[0016] FIG. 1 is a diagram showing a configuration of an example of a work machine 1.

[0017] As shown in FIG. 1, the work machine 1 includes a fuel cell system 100, a hydrogen tank 110, an actuator 120, an auxiliary load 130, a storage battery 140, an inverter device 150, an inverter device 160, and a DC / DC converter 170.

[0018] The work machine 1 drives the actuator 120 with electric power supplied from at least one of the fuel cell system 100 and the storage battery 140 to perform a predetermined task.

[0019] The work machine 1 is, for example, a mobile transfer crane. The work machine 1 may also be, for example, a stationary transfer crane or a gantry crane. The work machine 1 may also be a work machine for loading and unloading other than a crane, or may be a work machine for other purposes than loading and unloading. The following description will be given on the assumption that the work machine 1 is a crane.

[0020] The fuel cell system 100 provides power to the actuator 120 .

[0021] The fuel cell system 100 includes a fuel cell package 10 , a radiator 20 , and a control unit 30 .

[0022] The fuel cell package 10 includes a fuel cell module 40, a heat exchanger 50, an ion exchanger 60, an air cleaner 70, and a control power supply 80.

[0023] The fuel cell module 40 includes a fuel cell 41 , a cooling section 42 , and a converter device 43 .

[0024] The fuel cell 41 generates electricity by chemically reacting hydrogen supplied from the hydrogen tank 110 with oxygen in the air taken in from the outside. The fuel cell 41 is, for example, a polymer electrolyte fuel cell (PEFC). For example, the fuel cell 41 as a polymer electrolyte fuel cell has a stack structure in which a large number of unit cells are stacked.

[0025] A single cell in the fuel cell 41 has a membrane electrode assembly (MEA) including a polymer electrolyte membrane and a pair of electrodes provided on both sides of the polymer electrolyte membrane. The polymer electrolyte membrane selectively transports hydrogen ions. Each electrode is made of a porous material. Each of the pair of electrodes has a catalyst layer mainly composed of carbon powder supporting a platinum-based metal catalyst (electrode catalyst), for example, and a gas diffusion layer having both air permeability and electronic conductivity. Furthermore, the single cell has a pair of separators that sandwich the membrane electrode assembly (MEA) from both sides.

[0026] From the fuel cell module 40, exhaust gas is discharged after a chemical reaction between hydrogen from the fuel cell 41 and oxygen contained in the air SA.

[0027] The fuel cell 41 may be, for example, a phosphoric acid fuel cell (PAFC) or a solid oxide fuel cell (SOFC). The fuel cell 41 may be, for example, a molten carbonate fuel cell (MCFC).

[0028] The cooling unit 42 cools the fuel cell 41. Specifically, a coolant flows inside the cooling unit 42. The cooling unit 42 can cool the fuel cell 41 by exchanging heat between the fuel cell 41 and the coolant.

[0029] The converter device 43 boosts the voltage output from the fuel cell 41 and outputs it to the outside of the fuel cell module 40.

[0030] The heat exchanger 50 exchanges heat between the coolant in the cooling circuit CC1 including the radiator 20 and the coolant in the cooling circuit CC2 including the cooling unit 42, thereby cooling the coolant in the cooling circuit CC2. As a result, the cooling circuit CC2 can supply the coolant cooled by the heat exchanger 50 to the cooling unit 42, thereby cooling the fuel cell 41.

[0031] An ion exchanger 60 is provided in the cooling circuit CC2 to remove ionic impurities from the cooling liquid in the cooling circuit CC2.

[0032] The air cleaner 70 removes dust, impurities, etc. from the air SA taken in from the outside, and supplies the air SA from which dust, impurities, etc. have been removed to the fuel cell 41.

[0033] The control power supply 80 supplies power to control devices such as various sensors mounted on the fuel cell package 10 .

[0034] The radiator 20 cools the coolant in the cooling circuit CC1. As a result, the heat exchanger 50 performs heat exchange between the coolant in the cooling circuit CC1 and the coolant in the cooling circuit CC2 as described above, and can cool the coolant in the cooling circuit CC2. The radiator 20 is, for example, a fin-tube type or a fin-and-tube type radiator.

[0035] The inlet and outlet of the cooling water of the radiator 20 are connected to the inlet and outlet of the cooling water from the heat exchanger 50 in the fuel cell package 10, respectively, to form a cooling circuit CC1.

[0036] The control unit 30 performs control related to the operation of the work machine 1, including control related to the fuel cell system 100. For example, the control unit 30 performs control related to the exchange of power through the DC link 180 between the fuel cell system 100, the actuator 120, the auxiliary load 130, and the storage battery 140, including output control from the fuel cell system 100 to the DC link (also referred to as a DC bus) 180. At this time, the control unit 30 may control the fuel cell module 40, the inverter device 150, the inverter device 160, and the DC / DC converter 170 as direct control targets. The control unit 30 is, for example, a PLC (Programmable Logic Controller). Furthermore, the control unit 30 may be configured mainly with a computer including, for example, a CPU (Central Processing Unit), a memory device, an auxiliary storage device, and various interfaces.

[0037] The control unit 30 can communicate with the fuel cell package 10, the inverter device 150, the inverter device 160, and the DC / DC converter 170 through a predetermined communication line such as a one-to-one communication line or a local area network (LAN). As a result, the control unit 30 can obtain information indicating various states of the fuel cell package 10, the inverter device 150, the inverter device 160, and the DC / DC converter 170 from them, and control these components based on the information. The control unit 30 can also communicate with the storage battery 140 through a predetermined communication line such as a one-to-one communication line or a local area network (LAN). As a result, the control unit 30 can obtain information indicating various states of the storage battery 140, such as the current, voltage, and temperature, and control the fuel cell package 10, the inverter device 150, the inverter device 160, and the DC / DC converter 170 based on the information.

[0038] The hydrogen tank 110 stores high-pressure hydrogen and supplies high-pressure hydrogen gas to the fuel cell 41 of the fuel cell module 40. The hydrogen tank 110 is, for example, a hydrogen cartridge.

[0039] The actuator 120 is electrically driven by AC supplied through the inverter device 150, and drives a moving part that operates when the work machine 1 performs work. The actuator 120 corresponds to a load device (hereinafter referred to as "main engine load") that is electrically driven only in the operating state of the work machine 1, out of the operating state and standby state of the work machine 1. The operating state of the work machine 1 means a state in which the work machine 1 is actually performing a specified work among the states in which the work machine 1 is capable of performing work from start-up to shutdown, and the standby state of the work machine 1 means a state in which the work machine 1 is not performing a specified work.

[0040] The work machine 1 includes one or more actuators 120. The actuators 120 are, for example, electric motors for raising and lowering a load suspended by a crane serving as the work machine 1, or electric motors for moving a trolley. The actuators 120 may also be, for example, electric motors for driving wheels or the like for movement in the mobile work machine 1.

[0041] The auxiliary load 130 is operated by AC supplied through the inverter device 160. The auxiliary load 130 is a load device that is electrically driven when the work machine 1 is in both an operating state and a standby state.

[0042] The storage battery 140 is a secondary battery capable of supplying power to the actuator 120 and the auxiliary load 130. The storage battery 140 is, for example, a lithium ion battery with a liquid electrolyte. The storage battery 140 may also be, for example, an all-solid-state battery with a fixed electrolyte. Specifically, the storage battery 140 is electrically connected to the actuator 120 via a DC / DC converter 170 and an inverter device 150. The storage battery 140 can supply power to the actuator 120 through the DC / DC converter 170 and the inverter device 150. Similarly, the storage battery 140 is electrically connected to the auxiliary load 130 via the DC / DC converter 170 and the inverter device 160. The storage battery 140 can supply power to the auxiliary load 130 through the DC / DC converter 170 and the inverter device 160.

[0043] The inverter device 150 is a power conversion device that converts DC to three-phase AC and outputs it to the actuator 120. Specifically, the inverter device 150 is electrically connected to the converter device 43 by a DC link 180, converts the DC output from the fuel cell module 40 into three-phase AC, and outputs it to the actuator 120. In this way, the inverter device 150 can drive the actuator 120 using the output of the fuel cell system 100. In addition, the inverter device 150 is electrically connected to the DC / DC converter 170 by the DC link 180, converts the DC output from the storage battery 140 and supplied through the DC / DC converter 170 into three-phase AC, and outputs it to the actuator 120. In this way, the inverter device 150 can drive the actuator 120 using the output of the storage battery 140.

[0044] Furthermore, the inverter device 150 may convert the three-phase AC regenerated from the actuator 120 into DC and output it to the DC link 180. This allows the work machine 1 to supply the regenerated power output to the DC link 180 to the auxiliary load 130 via the inverter device 160, or charge the storage battery 140 via the DC / DC converter 170.

[0045] For example, the inverter device 150 is operated when the work machine 1 is in an operating state, and is stopped when the work machine 1 is in a standby state.

[0046] The inverter device 160 is a power conversion device that converts DC to three-phase AC and outputs it to the auxiliary load 130. Specifically, the inverter device 160 is electrically connected to the converter device 43 by a DC link 180, and converts the DC output from the fuel cell module 40 into three-phase AC and outputs it to the auxiliary load 130. In this way, the inverter device 160 can drive the auxiliary load 130 using the output of the fuel cell system 100. In addition, the inverter device 160 is electrically connected to the DC / DC converter 170 by the DC link 180, and converts the DC output from the storage battery 140 and supplied through the DC / DC converter 170 into three-phase AC and outputs it to the auxiliary load 130. In this way, the inverter device 160 can drive the auxiliary load 130 using the output of the storage battery 140. Moreover, the inverter device 160 is electrically connected to the inverter device 150 by a DC link 180, and converts the DC output from the inverter device 150 into a three-phase AC and outputs it to the auxiliary load 130. In this way, the inverter device 160 can drive the auxiliary load 130 by using the power regenerated from the actuator 120.

[0047] The DC / DC converter 170 is a power conversion device that converts direct current to direct current. Specifically, the DC / DC converter 170 converts the output of the storage battery 140 into direct current of a predetermined voltage and outputs it to a DC link 180 connected to the inverter devices 150, 160. This allows the work machine 1 to supply the output of the storage battery 140 from the DC link 180 to the actuator 120 via the inverter device 150, or to the auxiliary load 130 via the inverter device 160. The DC / DC converter 170 may also convert the direct current supplied to the DC link 180 from the fuel cell module 40 or the inverter device 150 into direct current of a predetermined voltage and output it to the storage battery 140. This allows the work machine 1 to charge the storage battery 140 using the output of the fuel cell module 40 or regenerative power of the actuator 120.

[0048] It should be noted that a plurality of DC / DC converters 170 and storage batteries 140 may be provided. In this case, a combination of a plurality of DC / DC converters 170 and storage batteries 140 is connected in parallel to the DC link 180. As a result, even if an abnormality occurs in one of the plurality of DC / DC converters 170, for example, the remaining DC / DC converters 170 and the storage batteries 140 connected to the remaining DC / DC converters 170 can continue to operate the work machine 1.

[0049] [Work machine operation mode] Next, the operation modes of the work machine 1 will be described with reference to FIG.

[0050] The following description will be given on the assumption that the control unit 30 is operable when the fuel cell system 100 is in a stopped state.

[0051] FIG. 2 is a state transition diagram showing an example of the transition of the operation mode of the work machine 1. As shown in FIG.

[0052] As shown in FIG. 1, the operation modes of the work machine 1 include an FC start mode M1, an initial mode M2, a standby mode M3, an operation mode M4, an FC stop mode M5, and a storage battery only mode M6.

[0053] The FC start-up mode M1 is an operating mode in which the fuel cell system 100 is started up in conjunction with the start-up of the work machine 1. The control unit 30 transitions to the FC start-up mode M1 in response to an FC start-up command accompanying the start-up operation of the work machine 1. For example, the FC start-up command is input to the control unit 30 from an integrated control device that performs overall control of the work machine 1.

[0054] The initial mode M2 ​​is an operation mode for charging the storage battery 140 to a predetermined initial state (target value TGT0) using a direct current output from the fuel cell system 100 after the FC start-up mode M1 ends. The target value TGT0 is, for example, 70%. When the start-up of the fuel cell system 100 is completed in the FC start-up mode M1, the control unit 30 transitions to the initial mode M2.

[0055] The standby mode M3 is an operation mode corresponding to a standby state of the work machine 1. When the SOC of the storage battery 140 reaches a predetermined target value TGT0 in the initial mode M2, the control unit 30 transitions to the standby mode M3.

[0056] In the standby mode M3, the inverter device 160 drives the auxiliary load 130 using the output of only the fuel cell system 100 or the output of both the fuel cell system 100 and the storage battery 140. That is, in the standby mode M3, the fuel cell system 100 always outputs power to the DC link 180, and the storage battery 140 may or may not output power to the DC link 180.

[0057] The operation mode M4 is an operation mode corresponding to the operation state of the work machine 1. In the standby mode M3, the control unit 30 transitions to the operation mode M4 when the work machine 1 transitions from the standby state to the operation state. Specifically, the control unit 30 may transition to the operation mode M4 when the inverter device 150 for the main load of the work machine 1 transitions from the stopped state to the operating state. For example, the operation of the inverter device 150 is started in response to an operation of the actuator 120 by a user, and power supply from the DC link 180 to the actuator 120 is started. In addition, in the operation mode M4, the control unit 30 transitions to the standby mode M3 when the work machine 1 transitions from the operating state to the standby state. Specifically, the control unit 30 may transition to the standby mode M3 when the inverter device 150 for the main load of the work machine 1 transitions from the operating state to the stopped state. For example, when the user stops operating the actuator 120, the inverter device 150 is stopped and the power supply from the DC link 180 to the actuator 120 is stopped.

[0058] The FC stop mode M5 is an operation mode for stopping the fuel cell system 100. When an FC stop command is input in the standby mode M3 or the operation mode M4, the control unit 30 transitions to the FC stop mode M5. For example, when a user performs an operation to stop the work machine 1, an FC stop command is input from the integrated control device to the control unit 30. Hereinafter, an FC stop command based on the user's intention to stop the work machine 1 may be referred to as a "normal FC stop command" for convenience. Also, for example, when the integrated control device determines that there is an abnormality or a sign of an abnormality in the fuel cell system 100, an FC stop command is input from the integrated control device to the control unit 30. Hereinafter, an FC stop command caused by an abnormality or the like in the fuel cell system 100 may be referred to as an "FC stop command under specific conditions" for convenience.

[0059] The work machine 1 stops in the FC stop mode M5 when the shutdown process of the fuel cell system 100 based on a normal FC stop command is completed. Furthermore, the work machine 1 transitions to the FC startup mode M1 when an FC startup command is input in the FC stop mode M5. For example, when a user performs an operation to cancel an operation to stop the work machine 1, an FC startup command is input from the integrated control device to the control unit 30. Furthermore, when an abnormality or a symptom of an abnormality in the fuel cell system 100 is eliminated, an FC startup command may be input from the integrated control device to the control unit.

[0060] The battery only mode M6 is an operation mode in which the actuator 120 and the auxiliary load 130 are operated only by the output of the battery 140. When the control unit 30 completes the shutdown process of the fuel cell system 100 based on the FC shutdown process under specific conditions in the FC stop mode M5, the control unit transitions to the battery only mode M6.

[0061] In the battery only mode M6, the work machine 1 stops when the SOC of the storage battery 140 reaches a predetermined lower limit value LL2. The lower limit value LL2 is, for example, 50%. Furthermore, in the battery only mode M6, the work machine 1 stops when a user performs an operation to stop the work machine 1.

[0062] [First example of operation control of a work machine] Next, a first example of operation control of the work machine 1 by the control unit 30 will be described with reference to Figs.

[0063] 3 to 5 are flowcharts that generally show a first example of processing related to the operation control of the work machine 1. In FIG.

[0064] The flowcharts in FIGS. 3 to 5 are repeatedly executed during the period from the completion of start-up of the work machine 1 to the start of the shutdown processing of the work machine 1.

[0065] As shown in FIG. 3, in step S102, the control unit 30 determines whether or not a condition for the operation mode of the work machine 1 to correspond to the FC start mode M1 (hereinafter, "FC start mode condition") is met.

[0066] The first of the FC start mode conditions is that an FC start command is input corresponding to the start-up process of the work machine 1. The second of the FC start mode conditions is that an FC start command is input in the FC stop mode. If any of the FC start mode conditions is satisfied, the control unit 30 proceeds to step S104, and otherwise proceeds to step S108.

[0067] In step S104, the control unit 30 sets the operation mode to the FC startup mode M1.

[0068] When the process of step S104 is completed, the control unit 30 proceeds to step S106.

[0069] In step S106, the control unit 30 performs a startup process for the fuel cell system 100. Specifically, the control unit 30 transmits a startup command to various components included in the fuel cell system 100, and starts up the various components from a stopped state to a state in which they can perform operations to perform the desired functions. The control unit 30 may also perform a refresh process for the fuel cell 41. The refresh process is a known process that adjusts the cathode potential of the fuel cell 41 and removes an oxide film from the catalyst surface to restore power generation performance. This allows the control unit 30 to suppress deterioration (decrease in power generation performance) of the fuel cell 41.

[0070] The refresh process may be performed as part of the shutdown process of the fuel cell system 100 in response to a normal FC shutdown command, instead of when the fuel cell system 100 is started up.

[0071] When the process of step S106, that is, the start-up process of the fuel cell system 100, is completed, the control unit 30 ends the process of this flowchart.

[0072] On the other hand, in step S108, the control unit 30 determines whether or not the condition for the operation mode of the work machine 1 to be in the initial mode M2 ​​(hereinafter, "initial mode condition") is met.

[0073] The first initial mode condition is that the startup process of the fuel cell system 100 in the FC startup mode M1 has been completed in the previous flowchart. The second initial mode condition is that the current operation mode is set to the initial mode M2, and the initial preparation for the work machine 1 to perform a predetermined task has not been completed (i.e., the condition of step S116 described below has not been met). If any of the initial conditions is met, the control unit 30 proceeds to step S110, and otherwise proceeds to step S120 as shown in FIG. 4.

[0074] In step S110, the control unit 30 sets the operation mode of the work machine 1 to the initial mode M2.

[0075] When the process of step S110 is completed, the control unit 30 proceeds to step S112.

[0076] In step S112, the control unit 30 checks the latest SOC of the storage battery 140. The SOC of the storage battery 140 is estimated based on, for example, information indicating the voltage of the storage battery 140, which is acquired from the storage battery 140. The control unit 30 may also acquire information regarding the SOC directly from the storage battery 140.

[0077] When the process of step S112 is completed, the control unit 30 proceeds to step S114.

[0078] In step S114, the control unit 30 determines whether the SOC of the storage battery 140 is equal to or greater than the target value TGT0. If the SOC of the storage battery 140 is not equal to or greater than the target value TGT0, the control unit 30 proceeds to step S116, and if the SOC is equal to or greater than the target value TGT0, the control unit 30 proceeds to step S118.

[0079] In step S116, the control unit 30 sets the output of the fuel cell module 40 to a predetermined value OP0 for charging the storage battery 140. As a result, the control unit 30 controls the fuel cell module 40 and the DC / DC converter 170 to charge the storage battery 140 with the output from the fuel cell module 40.

[0080] When the process of step S116 is completed, the control unit 30 ends this flow chart.

[0081] On the other hand, in step S118, the control unit 30 determines that the initial preparations for the work machine 1 to perform the specified work have been completed.

[0082] When the process of step S118 is completed, the control unit 30 proceeds to step S120.

[0083] In step S120, the control unit 30 determines whether or not the condition for the operation mode of the work machine 1 to correspond to the standby mode M3 (hereinafter, "standby mode condition") is met.

[0084] The first standby mode condition is that the current operation mode is the initial mode, and the initial preparation for the work machine 1 to perform a specified task is complete (i.e., the condition of step S116 described above is met). The second standby mode condition is that the current operation mode is the standby mode M3 or the operation mode M4, and the work machine 1 is currently in a standby state. If any of the standby mode conditions is met, the control unit 30 proceeds to step S122, and otherwise proceeds to step S126.

[0085] In step S122, the control unit 30 sets the operation mode of the work machine 1 to the standby mode M3.

[0086] When the process of step S122 is completed, the control unit 30 proceeds to step S124.

[0087] In step S124, the control unit 30 sets the output of the fuel cell module 40 to a predetermined value OP1 that corresponds to the standby state of the work machine 1. The predetermined value OP1 corresponds to the output of the fuel cell module 40 required when supplying power only to the actuator 120 or the auxiliary load 130. This enables the control unit 30 to control the fuel cell module 40 and the inverter device 160, and drive the auxiliary load 130 with the output of the fuel cell module 40. The predetermined value OP1 is, for example, a constant value (fixed value). Furthermore, the predetermined value OP1 may be a variable value that changes depending on the load state of the work machine 1, i.e., the load state of the auxiliary load 130.

[0088] When the process of step S124 is completed, the control unit 30 proceeds to step S132 as shown in FIG.

[0089] On the other hand, in step S126, the control unit 30 determines whether or not the condition for the operation mode of the work machine 1 to correspond to the operation mode M4 (hereinafter, "operation mode condition") is met.

[0090] The operation mode condition is that the current driving mode is the standby mode M3 or the operation mode M4, and the current working machine 1 is in an operation state. If the operation mode condition is met, the control unit 30 proceeds to step S128, and otherwise proceeds to step S148.

[0091] In step S128, the control unit 30 sets the operation mode of the work machine 1 to the operation mode M4.

[0092] When the process of step S128 is completed, the control unit 30 proceeds to step S130.

[0093] In step S130, the control unit 30 sets the output of the fuel cell module 40 to a predetermined value OP2 that corresponds to the operating state of the work machine 1. The predetermined value OP2 corresponds to the output of the fuel cell module 40 required to supply power to both the actuator 120 and the auxiliary load 130. This enables the control unit 30 to control the fuel cell module 40, the inverter device 150, and the inverter device 160, and drive the actuator 120 and the auxiliary load 130 with the output of the fuel cell module 40. The predetermined value OP2 is, for example, a constant value (fixed value). Furthermore, the predetermined value OP2 may be a variable value that changes depending on the load state of the work machine 1, i.e., the load states of the actuator 120 and the auxiliary load 130.

[0094] Upon completion of step S130, the control unit 30 proceeds to step S132, as shown in FIG.

[0095] In step S132, the control unit 30 checks the latest SOC and the amount of change in SOC of the storage battery 140. For example, the amount of change in SOC is the amount of change between the latest SOC of the storage battery 140 and the SOC of the storage battery 140 in the immediately preceding control cycle.

[0096] When the process of step S132 is completed, the control unit 30 proceeds to step S134.

[0097] In step S134, the control unit 30 determines whether the SOC of the storage battery 140 is equal to or greater than a target value TGT1 (≧TGT0). The target value TGT1 is a target value of the SOC of the storage battery 140 in the standby mode M3 and the operation mode M4. The target value TGT1 is, for example, 80%. If the SOC of the storage battery 140 is not equal to or greater than the target value TGT1, the control unit 30 proceeds to step S136, and if the SOC is equal to or greater than the target value TGT1, the control unit 30 proceeds to step S142.

[0098] In step S136, the control unit 30 determines whether the SOC of the storage battery 140 is increasing. For example, the control unit 30 determines that the SOC is increasing if the value obtained by subtracting the SOC of the storage battery 140 in the immediately preceding control cycle from the latest SOC of the storage battery 140 is equal to or greater than zero, and otherwise determines that the SOC is decreasing. If the SOC of the storage battery 140 is not increasing, the control unit 30 proceeds to step S138, and if the SOC is increasing, the control unit 30 proceeds to step S139.

[0099] In step S138, the control unit 30 increases the output of the fuel cell module 40 according to the SOC and the amount of change of the storage battery 140. In this way, the control unit 30 controls the fuel cell module 40 and the DC / DC converter 170, and can charge the storage battery 140 using the increase in the output of the fuel cell module 40. For example, the control unit 30 increases the output of the fuel cell module 40 so that the degree of increase increases as the SOC of the storage battery 140 decreases. In addition, the control unit 30 may increase the output of the fuel cell module 40 so that the degree of increase increases as the amount of change (decrease) of the SOC of the storage battery 140 increases. In this way, the control unit 30 can appropriately bring the SOC of the storage battery 140 close to the target value TGT1, and can prevent the SOC of the storage battery 140 from decreasing and becoming over-discharged.

[0100] The over-discharge state of the storage battery 140 means a state in which the SOC of the storage battery 140 is relatively low with respect to a predetermined lower limit value LL0. The SOC of the storage battery 140 being relatively low with respect to the lower limit value LL0 may mean that the SOC of the storage battery 140 is equal to or lower than the lower limit value LL0, or may mean that the SOC of the storage battery 140 is less than the lower limit value LL0. The lower limit value LL0 is, for example, 40%.

[0101] On the other hand, in step S139, the control unit 30 adjusts the output of the fuel cell module 40 according to the SOC of the storage battery 140 and the amount of change therein.

[0102] For example, the control unit 30 increases the output of the fuel cell module 40 when the difference between the current SOC of the storage battery 140 and the target value TGT1 is relatively large and the change (increase) of the storage battery 140 is relatively small. Whether the difference between the current SOC of the storage battery 140 and the target value TGT1 is relatively large and whether the change of the storage battery 140 is relatively small are determined based on a magnitude relationship with a predefined threshold. At this time, the control unit 30 may increase the output of the fuel cell module 40 so that the degree of increase increases as the change (increase) of the storage battery 140 decreases. In this way, the control unit 30 can control the fuel cell module 40 and the DC / DC converter 170 to increase the charging speed of the storage battery 140 in a situation where the current SOC of the storage battery 140 is smaller than the target value TGT1 and is relatively far from it. Therefore, the control unit 30 can appropriately bring the SOC of the storage battery 140 closer to the target value TGT1. Furthermore, the control unit 30 may reduce the output of the fuel cell module 40 when the difference between the current SOC of the storage battery 140 and the target value TGT1 is relatively small and the change (increase) of the storage battery 140 is relatively large. Whether the difference between the current SOC of the storage battery 140 and the target value TGT1 is relatively small and whether the change in the storage battery 140 is relatively large are determined based on the magnitude relationship with a predefined threshold. At this time, the control unit 30 may reduce the output of the fuel cell module 40 so that the degree of reduction increases as the change (increase) in the SOC of the storage battery 140 increases. In this way, the control unit 30 can control the fuel cell module 40 and the DC / DC converter 170 to reduce the charging speed of the storage battery 140 in a situation where the current SOC of the storage battery 140 is smaller than and relatively close to the target value TGT1. Therefore, the control unit 30 can suppress a situation where the SOC of the storage battery 140 significantly overshoots the target value TGT1.

[0103] Furthermore, in step S142, similarly to step S136, the control unit 30 determines whether or not the SOC of the storage battery 140 is increasing. If the SOC of the storage battery 140 is not increasing, the control unit 30 proceeds to step S144, and if the SOC is increasing, the control unit 30 proceeds to step S145.

[0104] In step S144, the control unit 30 adjusts the output of the fuel cell module 40 according to the SOC of the storage battery 140 and the amount of change therein.

[0105] For example, the control unit 30 reduces the output of the fuel cell module 40 when the difference between the current SOC of the storage battery 140 and the target value TGT1 is relatively large and the change (decrease) of the storage battery 140 is relatively small. Whether the difference between the current SOC of the storage battery 140 and the target value TGT1 is relatively large and whether the change (decrease) of the storage battery 140 is relatively small are determined based on a magnitude relationship with a predefined threshold. At this time, the control unit 30 may reduce the output of the fuel cell module 40 so that the degree of decrease increases as the change (decrease) of the storage battery 140 decreases. In this way, the control unit 30 can control the fuel cell module 40 and the DC / DC converter 170 to increase the discharge rate of the storage battery 140 in a situation where the current SOC of the storage battery 140 is larger than the target value TGT1 and is relatively far from it. Therefore, the control unit 30 can appropriately bring the SOC of the storage battery 140 closer to the target value TGT1. Furthermore, the control unit 30 may increase the output of the fuel cell module 40 when the difference between the current SOC of the storage battery 140 and the target value TGT1 is relatively small and the change (decrease) of the storage battery 140 is relatively large. Whether the difference between the current SOC of the storage battery 140 and the target value TGT1 is relatively small and whether the change (decrease) of the storage battery 140 is relatively large are determined based on the magnitude relationship with a predefined threshold. At this time, the control unit 30 may increase the output of the fuel cell module 40 so that the degree of increase increases as the change (decrease) of the SOC of the storage battery 140 increases. In this way, the control unit 30 can control the fuel cell module 40 and the DC / DC converter 170 to reduce the discharge rate of the storage battery 140 in a situation where the current SOC of the storage battery 140 is larger than and relatively close to the target value TGT1. Therefore, the control unit 30 can suppress a situation where the SOC of the storage battery 140 significantly overshoots the target value TGT1.

[0106] On the other hand, in step S145, the control unit 30 reduces the output of the fuel cell module 40 according to the SOC and the amount of change of the storage battery 140. As a result, the control unit 30 controls the fuel cell module 40 and the DC / DC converter 170, and can discharge the storage battery 140 to the actuator 120 and the auxiliary load 130 according to the reduction in the output of the fuel cell module 40. For example, the control unit 30 reduces the output of the fuel cell module 40 so that the degree of reduction increases as the SOC of the storage battery 140 increases. In addition, the control unit 30 may reduce the output of the fuel cell module 40 so that the degree of reduction increases as the amount of change (increase) of the SOC of the storage battery 140 increases. As a result, the control unit 30 can appropriately bring the SOC of the storage battery 140 close to the target value TGT1, and can prevent the SOC of the storage battery 140 from increasing and becoming overcharged.

[0107] The overcharged state of the storage battery 140 means a state in which the SOC of the storage battery 140 is relatively high with respect to a predetermined upper limit value UL0 (>LL0). The SOC of the storage battery 140 being relatively high with respect to the upper limit value UL0 may mean that the SOC of the storage battery 140 is equal to or higher than the upper limit value UL0, or may mean that the SOC of the storage battery 140 exceeds the upper limit value UL0. The upper limit value UL0 is, for example, 100%.

[0108] When any one of the processes in steps S138, S139, S144, and S145 is completed, the control unit 30 ends the process of this flowchart, as shown in FIG.

[0109] In addition, the operation of the control unit 30 corresponding to the processing of steps S134, S136, S138, S139, S142, S144, and S145 may be realized by a PI (Proportional Integral) regulator that operates based on the deviation between the SOC of the storage battery 140 and the target value TGT.

[0110] Also, as shown in FIG. 4, in step S148, the control unit 30 determines whether or not a condition that indicates that the operation mode of the work machine 1 corresponds to the FC stop mode M5 (hereinafter, "FC stop mode condition") is met.

[0111] The FC stop mode condition is that an FC stop command is input. If the FC stop mode condition is satisfied, the control unit 30 proceeds to step S150, and otherwise proceeds to step S154.

[0112] In step S150, the control unit 30 sets the operation mode of the work machine 1 to the FC stop mode M5.

[0113] When the process of step S150 is completed, the control unit 30 proceeds to step S152.

[0114] In step S152, the control unit 30 performs a process to stop the fuel cell system 100.

[0115] When the process of step S152, ie, the process of shutting down the fuel cell system 100, is completed, the control unit 30 ends the process of this flowchart, as shown in FIG.

[0116] On the other hand, in step S154, the control unit 30 determines whether or not the condition for the operation mode of the work machine 1 to correspond to the battery only mode (hereinafter, "battery only mode condition") is met.

[0117] The first battery only mode condition is that the current operation mode of the work machine 1 is the FC stop mode M5, and the stop processing of the fuel cell system 100 based on the FC stop processing under specific conditions is completed. The second battery only mode condition is that the current operation mode of the work machine 1 is the battery only mode, the SOC of the storage battery 140 is greater than the lower limit value LL2, and the user has not performed an operation to stop the work machine 1. If the battery only mode condition is met, the control unit 30 proceeds to step S156, and otherwise ends the processing of the current flowchart as shown in FIG.

[0118] In step S156, the control unit 30 sets the operation mode of the work machine 1 to the battery only mode M6.

[0119] When the process of step S156 is completed, the control unit 30 proceeds to step S158.

[0120] In step S158, the control unit 30 controls the inverter device 150, the inverter device 160, and the DC / DC converter 170 to operate the work machine 1 using only the output of the storage battery 140.

[0121] When the process of step S158 is completed, the control unit 30 proceeds to step S160.

[0122] In step S160, the control unit 30 checks the latest SOC of the storage battery 140.

[0123] When the process of step S160 is completed, the control unit 30 proceeds to step S162.

[0124] In step S162, the control unit 30 determines whether the SOC of the storage battery 140 is equal to or less than the lower limit value LL2. If the SOC of the storage battery 140 is not equal to or less than the lower limit value LL2, the control unit 30 proceeds to step S164, and if the SOC is equal to or less than the lower limit value LL2, ends the processing of this flowchart as shown in Fig. 3. This allows the control unit 30 to permit operation of the work machine 1 using only the output of the storage battery 140 for a limited period until the SOC of the storage battery 140 reaches the lower limit value LL2.

[0125] In step S164, the control unit 30 determines whether or not an operation to stop the work machine 1 has been performed by the user. If an operation to stop the work machine 1 has not been performed, the control unit 30 returns to step S158, and if an operation to stop the work machine 1 has been performed, the control unit 30 ends the processing of this flowchart as shown in Fig. 3. This allows the control unit 30 to stop the work machine 1 in accordance with the user's intention in the storage battery only mode M6.

[0126] [Specific examples of the operating conditions of work machines] Next, specific examples of the operating state of the work machine 1 will be described with reference to Figs.

[0127] <Example 1> Fig. 6 is a time chart showing a first example of the change over time of the output of the fuel cell module 40 and the state of charge (SOC) of the storage battery 140. Specifically, Fig. 6 includes Fig. 6A showing the change over time of the output of the fuel cell module 40 and Fig. 6B showing the change over time of the SOC of the storage battery 140.

[0128] As shown in Fig. 6A, at time t10, the work machine 1 is started and an FC start command is output (YES in step S102 in Fig. 3), and the control unit 30 sets the operation mode of the work machine 1 to the FC start mode M1 (step S102 in Fig. 3). As a result, from time t10 to time t11, the control unit 30 performs start-up processing of the fuel cell system 100 (step S106 in Fig. 3). Therefore, from time t10 to time t11, the output of the fuel cell module 40 is zero (0).

[0129] When the start-up process of the fuel cell system 100 is completed at time t11, the initial mode condition is met (YES in step S108 in FIG. 3), and the control unit 30 sets the operation mode of the work machine 1 to the initial mode M2 ​​(step S110 in FIG. 3). As a result, from time t11 to time t12, the control unit 30 sets the output of the fuel cell module 40 to a predetermined value OP0 (step S116 in FIG. 3), and charges the storage battery 140 with the output of the fuel cell module 40. Therefore, as shown in FIG. 6B, the SOC of the storage battery 140 increases after time t11, and reaches the target value TGT0 at time t12.

[0130] At time t12, when the SOC of the storage battery 140 reaches the target value TGT0 (YES in step S114 in FIG. 3), the standby mode condition is met (step S120 in FIG. 4), and the control unit 30 sets the operation mode of the work machine 1 to the standby mode M3 (step S122 in FIG. 4). As a result, after time t12, the control unit 30 sets the output of the fuel cell module 40 to a predetermined value OP1 (step S124 in FIG. 4). In this example, the predetermined value OP1 is a constant value.

[0131] In this example, since the target value TGT0 is smaller than the target value TGT1, the state in which the SOC of the storage battery 140 is smaller than the target value TGT1 continues from time t12 to t13 (NO in step S136 in FIG. 4). Also, in this example, when the output of the fuel cell module 40 is set to the predetermined value OP1 at time t12, the SOC of the storage battery 140 immediately begins to increase. Therefore, the control unit 30 maintains the output of the fuel cell module 40 at the predetermined value OP1 in response to the increase in the SOC of the storage battery 140 (YES in step S136 in FIG. 5) (step S139 in FIG. 5). Then, at time t13, the SOC of the storage battery 140 increases to near the target value TGT1.

[0132] When the work machine 1 transitions from a standby state to an operating state at time t13, the operation mode condition is met (YES in step S126 in FIG. 4), and the control unit 30 sets the driving mode of the work machine 1 to the operation mode M4 (step S128 in FIG. 4). As a result, at time t13, the control unit 30 sets the output of the fuel cell module 40 to a predetermined value OP2 (step S130 in FIG. 4). In this example, the predetermined value OP2 is a constant value. Therefore, starting from time t13, the output of the fuel cell module 40 rises from the predetermined value OP1 to the predetermined value OP2.

[0133] After the output of the fuel cell module 40 reaches the predetermined value OP2, the control unit 30 increases or decreases the output of the fuel cell module 40 in a relatively small range based on the predetermined value OP2, thereby maintaining the SOC of the storage battery 140 near the target value TGT1. Specifically, when the SOC of the storage battery 140 is less than the target value TGT1 (NO in step S134 in FIG. 5), the control unit 30 slightly increases the output of the fuel cell module 40 (step S138 in FIG. 5). On the other hand, when the SOC of the storage battery 140 is equal to or greater than the target value TGT1 (YES in step S134 in FIG. 5), the control unit 30 slightly decreases the output of the fuel cell module 40. In this example, the control unit 30 repeats this process to increase or decrease the SOC of the storage battery 140 based on the target value TGT1, thereby maintaining the SOC of the storage battery 140 near the target value TGT1. This allows the control unit 30 to keep the SOC of the storage battery 140 within a target range TR1 between the upper limit value UL1 and the lower limit value LL1, including the target value TGT1. Therefore, the control unit 30 can suppress deterioration of the storage battery 140. The upper limit value UL1 is a value equal to or less than the upper limit value UL0 corresponding to the above-mentioned overcharged state, for example, 90%. The lower limit value LL1 is a value equal to or more than the lower limit value LL0 corresponding to the above-mentioned overdischarged state, for example, 70%.

[0134] At time t14, an FC stop command under specific conditions is output, the FC stop mode conditions are established (YES in step S148 in FIG. 4), and the control unit 30 sets the operation mode of the work machine 1 to the FC stop mode M5 (step S150 in FIG. 4). As a result, after time t14, the control unit 30 performs a process to stop the fuel cell system 100 (step S152 in FIG. 4), and the output of the fuel cell module 40 becomes zero (0).

[0135] At time t15, when the shutdown process of the fuel cell system 100 is completed, the battery only mode condition is met (YES in step S154 in FIG. 4), and the control unit 30 sets the operation mode of the work machine 1 to the battery only mode M6 (step S156 in FIG. 4). As a result, from time t15 onwards, the control unit 30 controls the inverter device 150, the inverter device 160, and the DC / DC converter 170 to drive the actuator 120 and the auxiliary load 130 using only the output of the storage battery 140. Therefore, the SOC of the storage battery 140 decreases over time. Then, at time t16, the SOC of the storage battery 140 reaches the lower limit LL2 (YES in step S162 in FIG. 4), and the work machine 1 is stopped.

[0136] <Second Example> Fig. 7 is a time chart showing a second example of the change over time of the output of the fuel cell module 40 and the state of charge (SOC) of the storage battery 140. Specifically, Fig. 7 includes Fig. 7A showing the change over time of the output of the fuel cell module 40 and Fig. 7B showing the change over time of the SOC of the storage battery 140.

[0137] As shown in FIG. 7, the flow of time t20 → time t21 → time t22 → time t23 is the same as the flow of time t10 → time t11 → time t12 → time t13 in FIG. 6, and therefore a description thereof will be omitted.

[0138] When the work machine 1 transitions from a standby state to an operating state at time t23, the operation mode condition is met (YES in step S126 in FIG. 4), and the control unit 30 sets the driving mode of the work machine 1 to the operation mode M4 (step S128 in FIG. 4). As a result, after time t23, the control unit 30 sets the output of the fuel cell module 40 to a predetermined value OP2 (step S130 in FIG. 4). In this example, the predetermined value OP2 is a constant value. Therefore, starting from time t23, the output of the fuel cell module 40 increases from the predetermined value OP1 to the predetermined value OP2.

[0139] After the output of the fuel cell module 40 reaches the predetermined value OP2, the control unit 30 increases or decreases the output of the fuel cell module 40 in a relatively small increment with respect to the predetermined value OP2, as in the first example described above (FIG. 6), thereby maintaining the SOC of the storage battery 140 near the target value TGT1. This allows the control unit 30 to keep the SOC of the storage battery 140 within the target range TR1 between the upper limit value UL1 and the lower limit value LL1, which includes the target value TGT1. Therefore, the control unit 30 can suppress deterioration of the storage battery 140.

[0140] When the work machine 1 transitions from an operating state to a standby state at time t24, the standby mode condition is met and the control unit 30 sets the operation mode of the work machine 1 to the standby mode M3. As a result, at time t24, the control unit 30 sets the output of the fuel cell module 40 to a predetermined value OP1. Therefore, starting from time t24, the output of the fuel cell module 40 decreases from the predetermined value OP2 to the predetermined value OP1.

[0141] After the output of the fuel cell module 40 reaches the predetermined value OP1, the control unit 30 increases or decreases the output of the fuel cell module 40 in a relatively small range based on the predetermined value OP1, thereby maintaining the SOC of the storage battery 140 near the target value TGT1. Specifically, when the SOC of the storage battery 140 is less than the target value TGT1 (NO in step S134 in FIG. 5), the control unit 30 slightly increases the output of the fuel cell module 40 (step S138 in FIG. 5). On the other hand, when the SOC of the storage battery 140 is equal to or greater than the target value TGT1 (YES in step S134 in FIG. 5), the control unit 30 slightly decreases the output of the fuel cell module 40. In this example, the control unit 30 repeats this process to increase or decrease the SOC of the storage battery 140 based on the target value TGT1, thereby maintaining the SOC of the storage battery 140 near the target value TGT1. This allows the control unit 30 to keep the SOC of the storage battery 140 within a target range TR1 between the upper limit value UL1 and the lower limit value LL1, which includes the target value TGT1. Therefore, the control unit 30 can suppress deterioration of the storage battery 140.

[0142] At time t25, when the work machine 1 transitions from a standby state to an operating state, the operation mode condition is met and the control unit 30 sets the driving mode of the work machine 1 to the operation mode M4. In this example, after time t25, the operation mode M4 and the standby mode M3 are repeated in the same manner as in the sequence of time t23 → time t24 → time t25.

[0143] Thereafter, at time t26, which corresponds to standby mode M3, a normal FC stop command is output in response to an operation to stop the work machine 1, the FC stop mode condition is established (YES in step S148 in FIG. 4), and the control unit 30 sets the operation mode of the work machine 1 to FC stop mode M5 (step S150 in FIG. 4). As a result, after time t26, the control unit 30 performs a stop process for the fuel cell system 100 (step S152 in FIG. 4), and the output of the fuel cell module 40 becomes zero (0). Then, at time t27, when the stop process for the fuel cell system 100 is completed, the work machine 1 is stopped.

[0144] [Second example of operation control of a work machine] Next, a second example of operation control of the work machine 1 by the control unit 30 will be described with reference to FIG.

[0145] Hereinafter, in this example, the differences from the above-mentioned first example (FIGS. 3 to 5) will be mainly described, and description of the same or corresponding content as the above-mentioned first example may be omitted.

[0146] FIG. 8 is a flowchart showing a second example of processing related to the operation control of the work machine 1.

[0147] This example differs from the first example described above (FIGS. 3 to 5) in that the process in FIG. 5 is replaced with the process in FIG. 8, but is otherwise the same as the first example described above. Therefore, in this example, illustration of the process corresponding to FIG. 3 and FIG. 4 is omitted, and the description will be given with reference to FIG. 3 and FIG. 4.

[0148] Steps S102 to S134 are the same as in the first example described above, and therefore the explanation will be omitted.

[0149] In step S134, if the SOC of the storage battery 140 is not equal to or greater than the target value TGT1, the control unit 30 proceeds to step S135, and if the SOC is equal to or greater than the target value TGT1, the control unit 30 proceeds to step S41.

[0150] In step S135, the control unit 30 determines whether or not there is a sign of over-discharging of the storage battery 140.

[0151] The control unit 30 may use any method to determine whether or not there is a sign of over-discharge of the storage battery 140. For example, the control unit 30 determines that there is a sign of over-discharge when the difference between the SOC of the storage battery 140 and the lower limit value LL0 corresponding to over-discharge is relatively small. The control unit 30 may also determine that there is a sign of over-discharge of the storage battery 140 when the rate of decrease of the SOC of the storage battery 140 is relatively high. The control unit 30 may also determine that there is a sign of over-discharge of the storage battery 140 when the moving average of the rate of decrease of the SOC of the storage battery 140 is relatively high. The control unit 30 may also determine whether or not there is a sign of over-discharge of the storage battery 140 by considering both the difference between the SOC of the storage battery 140 and the lower limit value LL0 and the rate of decrease of the SOC of the storage battery 140. Furthermore, the control unit 30 may directly refer to the diagnosis result of an external diagnostic function (for example, a function built into the storage battery 140 that diagnoses various states of the storage battery 140, such as overcharging and overdischarging) to determine whether or not there is a sign of overdischarging of the storage battery 140. Whether or not the difference between the SOC of the storage battery 140 and a lower limit LL0 corresponding to overdischarging is relatively small, and whether or not the rate of decrease in the SOC of the storage battery 140 or its moving average is relatively high are determined based on the magnitude relationship with a predefined threshold. If there is no sign of overdischarging of the storage battery 140, the control unit 30 proceeds to step S136, and if there is a sign of overdischarging of the storage battery 140, the control unit 30 proceeds to step S140.

[0152] The processes in steps S136, S138, and S139 are the same as those in the first example described above, and therefore the description thereof will be omitted.

[0153] On the other hand, in step S140, the control unit 30 increases the output of the fuel cell module 40 in accordance with the SOC and the amount of change of the storage battery 140 so that the degree of increase is greater than when there is no sign of over-discharging of the storage battery 140. Specifically, the control unit 30 may increase the output of the fuel cell module 40 in accordance with the SOC and the amount of change of the storage battery 140 so that the sensitivity of the increase in accordance with the SOC and the amount of change of the storage battery 140 is greater than in step S138. This allows the control unit 30 to more appropriately suppress a decrease in the SOC of the storage battery 140 and more appropriately suppress over-discharging of the storage battery 140 when there is a sign of over-discharging of the storage battery 140.

[0154] Moreover, in step S141, the control unit 30 determines whether or not there is a sign that the storage battery 140 is being overcharged.

[0155] The control unit 30 may use any method to determine whether there is a sign of overcharging of the storage battery 140. For example, the control unit 30 determines that there is a sign of overcharging when the difference between the SOC of the storage battery 140 and the upper limit value UL0 corresponding to overcharging is relatively small. The control unit 30 may also determine that there is a sign of overcharging of the storage battery 140 when the increase rate of the SOC of the storage battery 140 is relatively high. The control unit 30 may also determine that there is a sign of overcharging of the storage battery 140 when the moving average of the increase rate of the SOC of the storage battery 140 is relatively high. The control unit 30 may also determine whether there is a sign of overcharging of the storage battery 140 by taking into account both the difference between the SOC of the storage battery 140 and the upper limit value UL0 and the increase rate of the SOC of the storage battery 140. The control unit 30 may also determine whether there is a sign of overcharging of the storage battery 140 by directly referring to the diagnosis result of an external diagnosis function. Whether the difference between the SOC of the storage battery 140 and the upper limit UL0 corresponding to overcharging is relatively small and whether the rate of increase in the SOC of the storage battery 140 or its moving average is relatively high are determined based on a magnitude relationship with a predefined threshold. If there is no sign of overcharging of the storage battery 140, the control unit 30 proceeds to step S142, and if there is a sign of overcharging of the storage battery 140, the control unit 30 proceeds to step S146.

[0156] The processes in steps S142, S144, and S145 are the same as those in the first example described above, and therefore the description thereof will be omitted.

[0157] On the other hand, in step S146, the control unit 30 reduces the output of the fuel cell module 40 in accordance with the SOC and the amount of change of the storage battery 140 so that the degree of decrease is greater than when there is no sign of overcharging of the storage battery 140. Specifically, the control unit 30 may reduce the output of the fuel cell module 40 in accordance with the SOC and the amount of change of the storage battery 140 so that the sensitivity of the decrease in accordance with the SOC and the amount of change of the storage battery 140 is greater than in step S145. This allows the control unit 30 to more appropriately suppress an increase in the SOC of the storage battery 140 and more appropriately suppress overcharging of the storage battery 140 when there is a sign of overcharging of the storage battery 140.

[0158] When any one of the processes in steps S138, S139, S140, S144, S145, and S146 is completed, the control unit 30 ends the process of this flowchart, as shown in FIG.

[0159] Steps S148 to S164 are the same as in the first example described above, and therefore the explanation will be omitted.

[0160] [Effect] Next, the operation of the fuel cell system, the control device, the work machine, and the control method according to this embodiment will be described.

[0161] In this embodiment, the fuel cell system includes a fuel cell and a control device. The fuel cell system is, for example, the fuel cell system 100 described above. The fuel cell is, for example, the fuel cell module 40 described above. The control device is, for example, the control unit 30 described above. Specifically, the fuel cell is capable of outputting power to a load device and a storage battery connected to be able to supply power to the load device. The load device is, for example, the actuator 120 and the auxiliary load 130 described above. The storage battery is, for example, the storage battery 140 described above. The control device controls the output of the fuel cell, taking into account both the output fluctuation of the fuel cell and the state of charge (SOC) of the storage battery.

[0162] In this embodiment, the control device controls the output of the fuel cell capable of outputting electric power to the load device and the storage battery connected to the load device so as to be able to supply electric power to the load device. Specifically, the control device controls the output of the fuel cell taking into consideration both the output fluctuation of the fuel cell and the charge state of the storage battery.

[0163] Moreover, in this embodiment, the work machine includes an actuator, a storage battery, a fuel cell, and a control device. The work machine is, for example, the work machine 1 described above. The actuator is, for example, the actuator 120 described above. Specifically, the actuator drives a movable part for performing work. Furthermore, the storage battery is connected so as to be able to supply power to the actuator. Furthermore, the fuel cell is able to output power to the actuator and the storage battery. Furthermore, the control device controls the output of the fuel cell, taking into account both output fluctuations of the fuel cell and the charge state of the storage battery.

[0164] In the present embodiment, the control method includes a control device controlling the output of a fuel cell capable of outputting electric power to a load device and a storage battery connected to the load device so as to be able to supply electric power to the load device. Specifically, the control method includes a control device controlling the output of the fuel cell taking into consideration both the output fluctuation of the fuel cell and the charge state of the storage battery.

[0165] This allows the control device to control the output of the fuel cell so as to suppress deterioration of both the fuel cell and the storage battery by taking into account output fluctuations of the fuel cell and the charge state of the storage battery, thereby enabling the control device to more appropriately suppress deterioration of both the fuel cell and the storage battery.

[0166] In this embodiment, the control device may control the output of the fuel cell in accordance with the load state of the load device so that the output fluctuation of the fuel cell is relatively small with respect to a predetermined standard and the charging rate of the storage battery falls within a predetermined range, for example the above-mentioned target range TR1.

[0167] As a result, the control device can suppress deterioration of the fuel cell by suppressing output fluctuations of the fuel cell, and can suppress deterioration of the storage battery by keeping the charging rate of the storage battery within a specified range. Furthermore, the control device can maintain a state in which the storage battery can store power equivalent to the regenerative energy of the load device by appropriately controlling the charging rate of the storage battery. Therefore, for example, when a situation occurs in which the storage battery cannot absorb the regenerative energy during the regenerative operation of the load device, a known DB (Dynamic Brake) circuit that prevents the DC circuit from becoming overvoltage is not required. This can reduce the costs of work machines and the like equipped with a hydrogen battery system.

[0168] In this embodiment, the control device may control the output of the fuel cell so that the charging rate of the storage battery increases or decreases based on a first target value for power storage that is within a predetermined range. The first target value for power storage is, for example, the target value TGT1 described above.

[0169] This allows the control device to suppress output fluctuations of the fuel cell while keeping the charging rate of the storage battery within a predetermined range.

[0170] In this embodiment, the control device may control the output of the fuel cell so that the charging rate of the storage battery reaches a second power storage target value set to be equal to or lower than the first power storage target value when a predetermined machine including a load device is started. The predetermined machine is, for example, the above-mentioned work machine 1. The second power storage target value is, for example, the above-mentioned target value TGT0.

[0171] This allows the control device to increase the charging rate to a relatively high state when the specified machine is started, and then start adjusting the charging rate while the specified machine is in operation. Therefore, the control device can suppress output fluctuations of the fuel cell to increase the charging rate while the specified machine is in operation. Therefore, the control device can more appropriately suppress output fluctuations of the fuel cell.

[0172] In this embodiment, the control device may control the output of the fuel cell so that the output of the fuel cell is increased or decreased based on an output target value set according to the load state of the load device, in accordance with the magnitude relationship between the charging rate of the storage battery and the first power storage target value. The output target value is, for example, a predetermined value OP1, OP2.

[0173] This allows the control device to control the output of the fuel cell so that the output of the fuel cell is increased or decreased with the output target value as a reference, thereby increasing or decreasing the output of the fuel cell with the first power storage target value as a reference.

[0174] In this embodiment, the output target value may be set to a first output target value when a specific machine including a load device is in a standby state, and may be set to a second output target value greater than the first output target value when the specific machine is in an operating state. The first output target value is, for example, the above-mentioned predetermined value OP1. The second output target value is, for example, the above-mentioned predetermined value OP2.

[0175] This allows the control device to control the output of the fuel cell in accordance with the power required for each of the standby and operating states of a given machine.

[0176] In the present embodiment, the first output target value and the second output target value may be constant values.

[0177] This allows the control device to control the output of the fuel cell to increase or decrease based on a fixed value in accordance with the power required for each of the operating and standby states of a given machine, thereby enabling the control device to further suppress fluctuations in the output of the fuel cell, and as a result, more appropriately suppress deterioration of the fuel cell.

[0178] In addition, in this embodiment, when there is a sign of an over-discharged state of the storage battery, in which the charging rate of the storage battery is relatively low with respect to a discharge limit value set to a lower limit value or lower of a predetermined range, or an over-charged state of the storage battery, in which the charging rate of the storage battery is relatively high with respect to a charge limit value set to a higher limit value or higher of a predetermined range, the control device may increase or decrease the output of the fuel cell so that the charging rate of the storage battery moves away from the discharge limit value or the charge limit value. The upper and lower limits of the predetermined range are, for example, the upper limit value UL1 and the lower limit value LL1 described above. The discharge limit value is, for example, the lower limit value LL0 described above. The charge limit value is, for example, the upper limit value UL0 described above.

[0179] This enables the control device to prevent the occurrence of an over-discharged or over-charged state of the storage battery.

[0180] In addition, in this embodiment, when there are signs of an over-discharged or over-charged state of the storage battery, the control device may increase or decrease the output of the fuel cell so that the charging rate of the storage battery deviates from the discharge limit value or the charge limit value to a greater extent than when there are no such signs.

[0181] This enables the control device to more appropriately prevent the occurrence of an over-discharged or over-charged state in the storage battery.

[0182] In this embodiment, the control device may perform a refresh operation of the fuel cell when a specific machine including a load device is started or stopped.

[0183] This allows the control device to suppress deterioration of the fuel cell.

[0184] Furthermore, in this embodiment, the work machine may include a DC bus electrically connected to the actuator, and a DC / DC converter provided between the DC bus and the storage battery. The DC bus is, for example, the above-mentioned DC link 180. The DC / DC converter is, for example, the above-mentioned DC / DC converter 170. Specifically, a plurality of combinations of storage batteries and DC / DC converters may be connected in parallel to the DC bus.

[0185] As a result, even if an abnormality occurs in one of the multiple DC / DC converters, the work machine can continue to operate using the remaining DC / DC converters and the storage battery connected to the remaining DC / DC converters.

[0186] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0187] 1. Work Machinery 10 Fuel Cell Package 20 Radiator 30 Control Unit 40 Fuel Cell Module 41 Fuel Cell 42 Cooling section 43 Converter device 50 heat exchanger 60 Ion Exchanger 70 Air cleaner 80 Control power supply 100 Fuel Cell System 110 Hydrogen Tank 120 Actuator 130 Auxiliary load 140 Battery 150,160 Inverter device 170 DC / DC Converter 180 DC Link CC1,CC2 Cooling circuit LL0, LL1, LL2 lower limit M1 FC boot mode M2 Initial Mode M3 Standby Mode M4 Operation Mode M5 FC stop mode M6 Battery only mode OP0~OP2 Predetermined value TGT0, TGT1 target value TR1 Target Range UL0,UL1 upper limit

Claims

1. a fuel cell capable of outputting electric power to a load device and a storage battery connected to the load device so as to be able to supply electric power to the load device; a control device that controls the output of the fuel cell in consideration of both the output fluctuation of the fuel cell and the charge state of the storage battery; Fuel cell system.

2. the control device controls the output of the fuel cell in accordance with a load state of the load device so that output fluctuation of the fuel cell is relatively small with respect to a predetermined standard and the charging rate of the storage battery falls within a predetermined range. The fuel cell system according to claim 1 .

3. the control device controls the output of the fuel cell so that the charging rate of the storage battery increases or decreases based on a first power storage target value included in the predetermined range. The fuel cell system according to claim 2 .

4. the control device controls the output of the fuel cell so that the charging rate of the storage battery reaches a second power storage target value that is set to be equal to or lower than the first power storage target value, when a predetermined machine including the load device is started up. The fuel cell system according to claim 3 .

5. the control device controls the output of the fuel cell so that the output of the fuel cell is increased or decreased based on an output target value that is set according to a load state of the load device, in accordance with a magnitude relationship between the charging rate of the storage battery and the first power storage target value.

5. The fuel cell system according to claim 3 or 4.

6. the output target value is set to a first output target value when a specific machine including the load device is in a standby state, and is set to a second output target value greater than the first output target value when the specific machine is in an operating state; The fuel cell system according to claim 5 .

7. The first output target value and the second output target value are constant values. The fuel cell system according to claim 6.

8. when there is a sign of an over-discharged state of the storage battery, in which the charging rate of the storage battery is relatively low with respect to a discharging limit value set to a lower limit value or lower of the predetermined range, or a sign of an over-charged state of the storage battery, in which the charging rate of the storage battery is relatively high with respect to a charging limit value set to a higher limit value or higher of the predetermined range, the control device increases or decreases the output of the fuel cell so that the charging rate of the storage battery moves away from the discharging limit value or the charging limit value; 5. A fuel cell system according to claim 2, wherein the fuel cell system comprises:

9. when there is a sign of the over-discharged state of the storage battery or the over-charged state of the storage battery, the control device increases or decreases the output of the fuel cell so that the charging rate of the storage battery deviates from the discharging limit value or the charging limit value to a greater extent than when there is no sign of the over-discharged state or the over-charged state of the storage battery. The fuel cell system according to claim 8 .

10. The control device performs a refresh operation of the fuel cell when a predetermined machine including the load device is started or stopped.

5. A fuel cell system according to claim 1.

11. A control device for controlling an output of a fuel cell capable of outputting electric power to a load device and a storage battery connected to the load device so as to be able to supply electric power thereto, controlling the output of the fuel cell in consideration of both the output fluctuation of the fuel cell and the charge state of the storage battery; Control device.

12. An actuator that drives a movable part to perform a task; a storage battery connected to the actuator so as to be able to supply power thereto; a fuel cell capable of outputting electric power to the actuator and the storage battery; a control device that controls the output of the fuel cell in consideration of both the output fluctuation of the fuel cell and the charge state of the storage battery; Working machinery.

13. A DC bus electrically connected to the actuator; a DC / DC converter provided between the DC bus and the storage battery; A plurality of combinations of the storage battery and the DC / DC converter are connected in parallel to the DC bus.

13. A work machine according to claim 12.

14. A control method for controlling an output of a fuel cell capable of outputting electric power to a load device and a storage battery connected to the load device so as to be able to supply electric power thereto, comprising: controlling the output of the fuel cell in consideration of both the output fluctuation of the fuel cell and the charge state of the storage battery; Control methods.

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