Work machine and method for controlling work machine

Abstract

A control device according to the present invention limits the operation of a work machine by outputting power from a power storage device from the start of the activation of a fuel cell until the completion of the activation of the fuel cell.

Description

Work machine and control method for work machine

[0001] The present disclosure relates to a work machine and a control method for a work machine. This application claims priority from Japanese Patent Application No. 2025-012629 filed in Japan on January 29, 2025, the content of which is incorporated herein by reference.

[0002] In the technical field related to work machines, work machines equipped with fuel cell modules are known. A fuel cell generates electrical energy through a chemical reaction between hydrogen and oxygen. Hydrogen, which is the fuel, is supplied from a tank filled with hydrogen gas. Also, oxygen is supplied from the atmosphere. It is known that starting a fuel cell takes time. Patent Document 1 discloses a technique for driving an object using only a secondary battery before starting a fuel cell.

[0003] Japanese Patent Application Laid-Open No. 2023-147515

[0004] By the way, in the technical field related to work machines, there is a demand to quickly operate the work machine immediately after starting the work machine. An object of the present disclosure is to provide a work machine and a control method for a work machine that can quickly operate the work machine equipped with a fuel cell immediately after starting.

[0005] According to one aspect of the present invention, a work machine is a work machine including a fuel cell, a work implement driven by electric power from a power storage device, and a control device, wherein the control device outputs electric power from the power storage device and restricts the operation of the work implement from the start of the startup of the fuel cell until the startup of the fuel cell is completed.

[0006] According to the above aspect, the work machine can quickly operate immediately after starting while mounting a fuel cell.

[0007] Perspective view of the work machine according to the first embodiment. Schematic block diagram showing the configuration of the work machine according to the first embodiment. Flowchart showing the control at the start of the work machine according to the first embodiment. Flowchart showing the control during operation of the work machine according to the first embodiment. Flowchart showing the control at the start of the work machine according to the second embodiment. Schematic block diagram showing the configuration of the computer according to the embodiment.

[0008] <First Embodiment> <Configuration of the Work Machine 1> Figure 1 is a perspective view of the work machine 1 according to the first embodiment. The work machine 1 according to the first embodiment is, for example, a hydraulic excavator. The work machine 1 comprises a traveling body 110, a rotating body 120, a work machine 130, a driver's cab 140, and a machine room 150. The work machine 1, which is a hydraulic excavator, excavates and levels soil and sand at a work site or the like. The traveling body 110 and the rotating body 120 constitute the vehicle body.

[0009] The traveling body 110 supports the work machine 1 so that it can move. The traveling body 110 has a pair of tracks on the left and right. The work machine 1 moves forward, turns, or moves backward by the rotation of the pair of tracks. The slewing body 120 is slewingly supported on the traveling body 110. The slewing body 120 turns relative to the traveling body 110 by an electric slewing motor 322, which will be described later. The slewing body 120 supports the work machine 130, the operator's cab 140, the machine room 150, and the fuel cell system 20.

[0010] The work machine 130 is operably supported on the body of the work machine 1. The work machine 130 comprises a boom 131, an arm 132, and an attachment 133 which is a work tool. The attachment 133 is an example of a work tool. In the example shown in Figure 1, the attachment 133 is a bucket. The base end of the boom 131 is rotatably attached to the front end of the slewing body 120. The base end of the arm 132 is rotatably attached to the tip of the boom 131. The attachment 133 is rotatably attached to the tip of the arm 132.

[0011] The work machine 130 is driven by multiple actuators. These actuators include, for example, a boom cylinder 131C, an arm cylinder 132C, and an attachment cylinder 133C.

[0012] The boom cylinder 131C is a hydraulic cylinder for driving the boom 131. The base end of the boom cylinder 131C is attached to the slewing body 120. The tip end of the boom cylinder 131C is attached to the boom 131. The arm cylinder 132C is a hydraulic cylinder for driving the arm 132. The base end of the arm cylinder 132C is attached to the boom 131. The tip end of the arm cylinder 132C is attached to the arm 132. The attachment cylinder 133C is a hydraulic cylinder for driving the attachment 133. The base end of the attachment cylinder 133C is attached to the arm 132. The tip end of the attachment cylinder 133C is attached to the attachment 133.

[0013] The operator's cab 140 is where the operator of the work machine 1 sits and operates and controls it. The operator's cab 140 is located, for example, on the left side of the front end of the slewing body 120. The operator's cab 140 of the work machine 1 is equipped with an operating device 142 for operating the work machine 1 and a power switch 143.

[0014] The operating device 142 is operated by an operator to operate the work machine 1. The operating device 142 outputs an operation signal in response to the operator's operation. The power switch 143 is a switch for starting or stopping the operation of the work machine 1. The power switch 143 outputs a signal in response to the operator's operation. When the power switch 143 is turned ON when the power to the work machine is OFF, it outputs a start request signal. When the power switch 143 is turned OFF when the power to the work machine is ON, it outputs a stop request signal. The power switch 143 may also be a switch that outputs a start request signal when pressed by an operator when the power to the work machine 1 is OFF, and outputs a stop request signal when pressed by an operator when the power to the work machine 1 is ON. Alternatively, for example, the power switch 143 may be a key switch that is operated by rotating a key from the OFF position through the ON position to the start position. In this case, the power switch 143 outputs a start request signal when the key is rotated from the OFF position to the start position, and outputs a stop request signal when the key is rotated from the ON position to the OFF position. For example, the power switch 143 may be a portable operating device held by the operator, and by operating the portable operating device, wireless communication may be performed between the portable operating device and the main control device 145, and a start request signal and a stop request signal may be output depending on the success of the communication. The portable operating device may be, for example, a remote control key with a built-in electronic chip, or a portable computer device such as a smartphone or personal digital assistant. In addition, the power switch 143 may be located in a remote location and configured to output a start request signal and a stop request signal by remote operation.

[0015] The main control unit 145 controls the work machine 1. The main control unit 145 receives operation signals from the operating device 142. Based on the operation signals from the operating device 142, the main control unit 145 controls the movement of the traveling body 110, the driving of the work machine 130, and the slewing operation of the slewing body 120. Based on the operation signals from the operating device 142, the main control unit 145 determines the amount of operation for the traveling body 110, the amount of operation for the work machine 130, and the amount of operation for the slewing body 120. Based on the amount of operation for the traveling body 110, the amount of operation for the work machine 130, and the amount of operation for the slewing body 120, the main control unit 145 controls the drive system 20, which will be described later.

[0016] The main control unit 145 receives a signal from the power switch 143. When the main control unit 145 receives a start request signal from the power switch 143, it starts the work machine 1. When the main control unit 145 receives a start request signal from the power switch 143, it performs the start process for each fuel cell module. When the main control unit receives a stop request signal from the power switch 143, it stops the work machine 1. When the main control unit 145 receives a stop request signal from the power switch 143, it performs the stop process for each fuel cell module. The main control unit 145 has a display 145D.

[0017] The machine room 150 houses the fuel cell system 20, which will be described later. The machine room 150 is located, for example, behind the driver's cab 140. The machine room 150 forms a space for housing the fuel cell system 20.

[0018] Figure 2 is a schematic block diagram showing the configuration of the work machine 1 according to the first embodiment. The work machine 1 comprises a fuel cell system 20 and a drive system 30. The fuel cell system 20 generates electricity to drive the work machine 1. The fuel cell system 20 also generates electricity to drive the drive system 30. The electricity generated by the fuel cell system 20 is output to the drive system 30 via the busbar B. The drive system 30 uses the electricity generated by the fuel cell system 20 to perform the movement of the traveling body 110, the driving of the work machine 130, and the rotation of the rotating body 120.

[0019] The fuel cell system 20 comprises a plurality of fuel cell modules 21 and an energy storage module 22 connected in parallel to the busbar B. In other embodiments, the fuel cell system 20 may comprise only one fuel cell module 21.

[0020] Each fuel cell module 21 comprises a fuel cell 211, a power converter 212, auxiliary equipment 213, and a fuel cell control device 214. The fuel cell 211 generates electricity by an electrochemical reaction between hydrogen and oxygen. The power converter 212 is, for example, a DC-DC converter and is configured to control the output of the electricity generated by the fuel cell 211. The power converter 212 converts the electricity generated by the fuel cell 211 and supplies it to busbar B. The auxiliary equipment 213 is equipment for operating the fuel cell 211. The fuel cell module 21 includes, as auxiliary equipment 213, a hydrogen pump for supplying hydrogen gas to the fuel cell 211, an air compressor for generating compressed air to supply to the fuel cell 211, and a water pump for supplying cooling water to cool the fuel cell 211. The fuel cell control device 214 controls the fuel cell module 21 according to commands from the main control device 145. The fuel cell control device 214 monitors the status of the fuel cell 211 and outputs data indicating the status of the fuel cell 211 to the main control device 145.

[0021] The energy storage module 22 comprises an energy storage device 221 and a power converter 222. The energy storage device 221 is configured to charge or discharge surplus power from busbar B. The power converter 222 is, for example, a DC-DC converter and controls the input and output of power to the energy storage device 221. The power converter 222 causes the energy storage device 221 to output power according to commands from the main control device 145. The energy storage device 221 is, for example, a battery.

[0022] The drive system 30 includes a hydraulic drive module 31 and a slewing module 32.

[0023] The hydraulic drive module 31 comprises an inverter 311, an electric pump motor 312, a hydraulic pump 313, and a hydraulic actuator 314. The inverter 311 converts the DC current from the busbar B into a three-phase AC current and supplies it to the electric pump motor 312. The electric pump motor 312 generates power to drive the work machine 130 and the traveling body 110. The electric pump motor 312 rotates with the supplied three-phase AC current and drives the hydraulic pump 313. The hydraulic pump 313 discharges hydraulic fluid to be supplied to the hydraulic actuator 314. The hydraulic fluid discharged from the hydraulic pump 313 is supplied to the hydraulic actuator 314 via a control valve (not shown). The hydraulic actuator 314 is driven by the supplied hydraulic fluid. The hydraulic actuator 314 includes a boom cylinder 131C, an arm cylinder 132C, an attachment cylinder 133C, and a travel motor 134. The rotational force generated by the travel motor 134 is transmitted to the travel body 110. The electric pump motor 312 is an example of a load.

[0024] The slewing module 32 includes an inverter 321 and an electric slewing motor 322. The inverter 321 converts the DC current from busbar B into a three-phase AC current and supplies it to the electric slewing motor 322. The electric slewing motor 322 generates power to rotate the slewing body 120. The electric slewing motor 322 rotates using the supplied three-phase AC current, causing the slewing body 120 to rotate relative to the traveling body 110. The electric slewing motor 322 is an example of a load.

[0025] 《Control of the work machine 1 when it is started》 Figure 3 is a flowchart showing the control of the work machine 1 when it is started according to the first embodiment. When the operator operates the power switch 143, the power switch 143 outputs a command signal to the main control device 145 to start the work machine 1. The power switch 143 is a switch that outputs a command signal to start the work machine 1 when pressed by the operator, for example. When the command signal to start the work machine 1 is input from the power switch 143 to the main control device 145 by the operator's operation, the main control device 145 starts the fuel cell system 20 in the following procedure. First, the main control device 145 outputs a command signal to the power converter 222 of the energy storage device module 22 to supply a predetermined amount of power to the busbar B (step S1).

[0026] The main control unit 145 outputs a start command to the fuel cell control unit 214 of the fuel cell module 21 (step S2). When the fuel cell control unit 214 of the fuel cell module 21 to be started receives the start command, it drives the auxiliary equipment 213 with the power from busbar B. When hydrogen and oxygen are supplied to the fuel cell 211 of the fuel cell module 21 to be started by the driving of the auxiliary equipment 213, the fuel cell 211 reacts the hydrogen and oxygen to generate water and electricity.

[0027] The main control unit 145 starts notifying the operator that the system is in work restriction mode (step S3). Specifically, the main control unit 145 displays a message on the display 145D indicating that the system is in work restriction mode, and starts sounding a buzzer to indicate that the system is in work restriction mode.

[0028] The main control unit 145 receives data from the fuel cell control unit 214 and determines whether or not the fuel cell module 21 has finished starting up (step S4). The fuel cell control unit 214 monitors the status of the fuel cell 211 and outputs data indicating the status of the fuel cell 211. The status of the fuel cell 211 includes states such as stopped and started up.

[0029] If the fuel cell module 21 has not finished starting up (step S4: NO), the main control unit 145 sets the upper limit of the operating range of the boom 131, arm 132, and attachment 133 to a limit operating range smaller than the maximum operating range of each hydraulic actuator 314 (step S5). The main control unit 145 returns to step S4 and continues to determine whether the fuel cell module 21 has finished starting up. In other words, the main control unit 145 starts startup control, which outputs power from the energy storage device 221 and limits the operation of the work machine 130 until startup is complete.

[0030] If the fuel cell module 21 has finished starting up in step S4 (step S4: YES), the main control unit 145 stops notifying the operator that it is in work restriction mode (step S6). In other words, the main control unit 145 stops the display and buzzer that started in step S3 indicating that it is in work restriction mode.

[0031] The main control unit 145 increases the upper limit of the manipulative amount of the boom 131, arm 132, and attachment 133 according to a predetermined rate (step S7). The main control unit 145 determines whether the upper limit of the manipulative amount has reached the maximum manipulative amount (step S8). If the upper limit of the manipulative amount has not reached the maximum manipulative amount (step S8: NO), the main control unit 145 returns to step S7 and continues to increase the upper limit of the manipulative amount. If the upper limit of the manipulative amount has reached the maximum manipulative amount (step S8: YES), the main control unit 145 terminates the startup control.

[0032] Figure 4 is a flowchart showing the control of the work machine 1 during operation according to the first embodiment. The main control device 145 controls the fuel cell system 20 and the drive system 30 according to the operation signals from the operating device 142 from the start to the stop of the work machine 1. Upon receiving an operation signal from the operating device 142, the main control device 145 determines a corrected operation amount that limits the amount of operation of the boom 131, arm 132, and attachment 133 indicated by the received operation signal to below the upper limit of the operation amount (step S21). The main control device 145 determines the power required by the electric pump motor 312 based on the corrected operation amounts of the boom 131, arm 132, and attachment 133 and the amount of operation of the travel motor 134 (step S22). The main control device 145 also determines the power required by the electric slewing motor 322 based on the amount of operation of the slewing operation (step S23).

[0033] The main control unit 145 determines whether the fuel cell module 21 has finished starting up (step S24). If the fuel cell module 21 has not finished starting up (step S24: NO), the main control unit 145 determines the power to be output to the energy storage module 22 from the sum of the required power of the electric pump motor 312 and the required power of the electric swing motor 322, and outputs a control command to the power converter 222 (step S25). If the fuel cell module 21 has finished starting up (step S24: YES), the main control unit 145 outputs a control command to the fuel cell control unit 214 to output a predetermined amount of power (step S26). The main control unit 145 determines the power to be output to or charged to the energy storage unit 221 by subtracting the sum of the required power of the electric pump motor 312 and the required power of the electric swing motor 322 from the power output by the fuel cell module 21, and outputs a control command to the power converter 222 (step S27).

[0034] The main control device 145 outputs a control command to the inverter 311 of the hydraulic drive module 31 according to the required power determined in step S22, and outputs a control command to the inverter 321 of the slewing module 32 according to the required power determined in step S23 (step S28). Based on the correction operation amounts of the boom 131, arm 132, and attachment 133 determined in step S21 and the operation amount of the travel motor 134, the main control device 145 determines the flow rate ratio of the hydraulic fluid of each hydraulic actuator 314 and controls a flow rate adjustment valve (not shown) (step S29).

[0035] 《Function and Effects》 The main control device 145 drives the traveling body 110, the rotating body 120, and the work machine 130 using power supplied from the energy storage module 22 until the fuel cell module 21 has finished starting up. At this time, the main control device 145 limits the amount of operation of the work machine 130 so that it is less than or equal to the limit amount. This prevents excessive discharge of the energy storage module 22 while power supply from the fuel cell module 21 is unavailable. Furthermore, by limiting the operation of the work machine 130 and prioritizing travel by the traveling body 110, the work machine 1 can be moved quickly. This is because it is assumed that the work machine 1 will need to be moved to a location where it will not be in the way, as this is a situation where operation immediately after the start-up of the work machine 1 is required. In addition, by not prohibiting the operation of the work machine 130 and allowing minimal operation, it is possible to position the work machine 130 for travel or to move the work machine 130 to avoid obstacles. The restriction on the operation of the work implement 130 may be a restriction on speed (flow rate of hydraulic fluid), or a restriction on the horsepower of the hydraulic actuator 314 related to the work implement 130. Alternatively, the restriction on the operation of the work implement 130 may be a prohibition on the operation of the work implement 130.

[0036] Furthermore, after the fuel cell module 21 has finished starting up, the main control device 145 increases the upper limit of the manipulated amount at a predetermined rate and releases the restriction. This prevents a sudden change in the operating speed of the hydraulic actuator 314 immediately after the fuel cell module 21 has finished starting up.

[0037] <Second Embodiment> In the first embodiment, the main control device 145 transmits a start command to multiple fuel cell modules 21 simultaneously in step S2. In contrast, the main control device 145 in the second embodiment starts the multiple fuel cell modules 21 one by one in sequence.

[0038] The configuration of the work machine 1 according to the second embodiment is the same as that of the first embodiment.

[0039] 《Control of the work machine 1 during startup》 Figure 5 is a flowchart showing the control of the work machine 1 during startup according to the second embodiment. When a command signal to start the work machine 1 is input from the power switch 143 to the main control device 145 by the operator's operation, the main control device 145 starts the fuel cell system 20 in the following procedure. First, the main control device 145 outputs a command signal to the power converter 222 of the energy storage device module 22 to supply a predetermined amount of power to the busbar B (step S101). The main control device 145 starts notifying the operator that it is in work restriction mode (step S102).

[0040] The main control unit 145 sets the upper limit of the operating amount of the boom 131, arm 132, and attachment 133 to the limited operating amount when none of the fuel cell modules 21 are started (step S103). In other words, the main control unit 145 starts startup control, which outputs power from the energy storage device 221 and limits the operation of the work machine 130 until the startup of at least one fuel cell module 21 is complete. In the second embodiment, the limited operating amount increases according to the number of started fuel cell modules 21. However, the limited operating amount is less than or equal to the maximum operating amount. The main control unit 145 outputs a startup command to the fuel cell control unit 214 of one of the fuel cell modules 21 that are not started (step S104).

[0041] The main control unit 145 determines whether the upper limit of the control amount is greater than or equal to the limit control amount (step S105). If the upper limit of the control amount is less than the limit control amount (step S105: NO), the main control unit 145 increases the upper limits of the control amounts of the boom 131, arm 132, and attachment 133 according to a predetermined rate (step S106). If the upper limit of the control amount is greater than or equal to the limit control amount (step S105: YES), or if the upper limit of the control amount was increased in step S106, the main control unit 145 receives data from the fuel cell control unit 214 that sent the start command in step S104 and determines whether the start of the fuel cell module 21 has been completed (step S107).

[0042] If the fuel cell module 21 has not finished starting up (step S107: NO), the main control unit 145 returns to step S105. If the fuel cell module 21 has finished starting up (step S107: YES), the main control unit 145 updates the limit operation amount according to the number of started fuel cell modules 21 (step S108). Next, the main control unit 145 determines whether there are any fuel cell modules 21 that have not started up (step S109). If there are any fuel cell modules 21 that have not started up (step S109: YES), the main control unit 145 returns to step S104 and sends a start command to the fuel cell modules 21 that have not started up.

[0043] On the other hand, if all fuel cell modules 21 are started (step S109: NO), the control device 145 stops notifying the operator that it is in work restriction mode (step S110).

[0044] The main control device 145 determines whether the upper limit value of the operation amount has reached the maximum operation amount (step S111). When the upper limit value of the operation amount has not reached the maximum operation amount (step S111: NO), the main control device 145 increases the upper limit values of the operation amounts of the boom 131, the arm 132, and the attachment 133 according to a predetermined rate (step S112), and repeats the determination in step S111. When the upper limit value of the operation amount has reached the maximum operation amount (step S111: YES), the main control device 145 ends the startup control.

[0045] 《Function and Effect》 As described above, the main control device 145 according to the second embodiment sequentially starts the fuel cell modules 21. In order to start the fuel cell module 21, power supply to the auxiliary device 213 is required. Depending on the amount of power stored in the power storage device 221, there may be insufficient power to start all the fuel cell modules 21 simultaneously. As in the second embodiment, the power required to start one fuel cell module 21 is small. Once one fuel cell module 21 is started, the power generated by the started fuel cell module 21 can be supplied to the auxiliary device 213 of another fuel cell module 21. Therefore, the main control device 145 according to the second embodiment can start a plurality of fuel cell modules 21 regardless of the remaining power amount of the power storage device 221.

[0046] Further, the main control device 145 according to the second embodiment increases the restricted operation amount according to the number of the started fuel cell modules 21. That is, the main control device 145 relaxes the restriction on the operation amount without waiting for all the fuel cell modules 21 to start. Thereby, the main control device 145 can quickly relax the restriction on the operation amount as compared with the method of releasing the restriction after waiting for all the fuel cell modules 21 to start.

[0047] The main control device 145 according to the second embodiment activates the plurality of fuel cell modules 21 one by one in sequence, but is not limited thereto. For example, the main control device 145 according to other embodiments may output a start command to the fuel cell control 214 for a group of two or more fuel cell modules 21 that have not been started. Further, the main control device 145 according to other embodiments may start one fuel cell module 21 immediately after the start of the working machine 1, and start the plurality of fuel cell modules 21 after the start of the one fuel cell module 21. That is, the main control device 145 may activate at least a part of the plurality of fuel cell modules 21 at different timings.

[0048] <Other Embodiments> Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes and the like are possible. For example, the main control device 145 according to the above-described embodiment may be constituted by a single computer, or the configuration of the main control device 145 may be divided and arranged in a plurality of computers, and the plurality of computers may function as the main control device 145 by cooperating with each other. At this time, a part of the computers constituting the main control device 145 may be mounted inside the working machine 1, and other computers may be provided outside the working machine 1. Further, the main control device 145 according to the above-described embodiment may have the function of the fuel cell control device 214. In this case, each fuel cell module 21 may not include the fuel cell control device 214, and the power converter 212 and the compensator 213 of each fuel cell module 21 may operate based on a command signal from the main control device 145. Further, the main control device 145 may have a function of monitoring the state of the fuel cell 211 as a monitoring device.

[0049] The work machine 1 according to the above-described embodiment restricts the operation of the work machine 130 until the fuel cell module 21 has finished starting up, but does not restrict the operation of the traveling body 110 and the rotating body 120, however, it is not limited to this. For example, the work machine 1 according to another embodiment may restrict the operation of the rotating body 120 in addition to the work machine 130 until the fuel cell module 21 has finished starting up. Furthermore, the work machine 1 according to the above-described embodiment monitors the fuel cell module 21 to determine when the startup is complete and restricts the operation of the work machine 130 until the startup of the fuel cell module 21 is complete, however, it is not limited to this. For example, the work machine 1 according to another embodiment may release the restriction on the operation of the work machine 130 after a certain amount of time has elapsed since the startup of the fuel cell module 21. In this case, the main control device 145 may release the restriction on the operation of the work machine 130 without determining whether or not the startup of the fuel cell module 21 has finished. In this case as well, the main control unit 145 initiates startup control, which involves outputting power from the energy storage module 22 and restricting the operation of the work machine 130, from the time the fuel cell module 21 starts up until it is fully started. The main control unit 145 only needs to initiate startup control before the fuel cell module 21 is fully started up.

[0050] Furthermore, while the work machine 1 in the above-described embodiment is a hydraulic excavator, it is not limited to this. For example, the work machine 1 in other embodiments may be other work machines such as a wheel loader or a dump truck.

[0051] Furthermore, in the above-described embodiment of the work machine 1, the electric slewing motor 322 of the slewing module 32 rotates the slewing body 120, but this is not limited to this. For example, in the work machine 1 according to another embodiment, there is no slewing module 32, and the hydraulic slewing motor, which is a hydraulic actuator 314, rotates the slewing body 120.

[0052] Furthermore, in the above-described embodiment of the work machine 1, the electric pump motor 312 drives the hydraulic actuator 314 to drive the work machine 130 and the traveling body 110, but this is not limited to this. For example, the work machine 1 may be equipped with an electric actuator instead of the electric pump motor 312 and hydraulic actuator 314, and the electric actuator may be used to drive the work machine 130 and the traveling body 110. Also, for example, in another embodiment of the work machine 1, the traveling motor 134, which is the hydraulic actuator 314, may be equipped with an electric traveling motor, and the work machine 130 may be driven by hydraulics and the traveling body may be used by the electric motor.

[0053] Furthermore, while a battery was given as an example of the energy storage device 221 in the above-described embodiment, it is not limited to this. For example, the energy storage device 221 of the work machine 1 according to another embodiment may be a capacitor. Also, while the energy storage device module 22 of the work machine 1 according to the above-described embodiment includes a power converter 222 and the main control device 145 controls the charging and discharging of the energy storage device 221 by outputting instructions for the energy storage device 221 to the power converter 222, it is not limited to this. For example, in cases where the energy storage device 221 according to another embodiment is provided to maintain a constant voltage of the busbar B, the energy storage device module 22 may not include a power converter 222, and charging and discharging may be performed according to the difference between the terminal voltage of the energy storage device 221 and the voltage of the busbar B.

[0054] <Computer Configuration> Figure 6 is a schematic block diagram showing the configuration of a computer according to the embodiment. The computer 90 includes a processor 91, main memory 92, storage 93, and interface 94. The main control unit 145 and fuel cell control unit 214 described above are implemented in the computer 90. The operation of each of the above-mentioned processing units is stored in the storage 93 in the form of a program. The processor 91 reads the program from the storage 93, loads it into the main memory 92, and executes the above-mentioned processing according to the program. The processor 91 also allocates storage areas in the main memory 92 corresponding to each of the above-mentioned storage units according to the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0055] The program may be for implementing a part of the functions to be performed by the computer 90. For example, the program may perform functions in combination with other programs already stored in storage, or in combination with other programs implemented on other devices. In other embodiments, the computer 90 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to, or instead of, the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions implemented by the processor 91 may be implemented by the integrated circuit. Such an integrated circuit is also included as an example of a processor. In other embodiments, the computer 90 may be virtualized on one or more computers.

[0056] Examples of storage 93 include magnetic disks, magneto-optical disks, optical disks, and semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of the computer 90, or it may be an external medium connected to the computer 90 via an interface 94 or a communication line. Furthermore, if this program is distributed to the computer 90 via a communication line, the computer 90 that receives the distribution may expand the program into the main memory 92 and execute the above processing. In at least one embodiment, storage 93 is a tangible storage medium that is not temporary.

[0057] Furthermore, the program may be intended to implement some of the functions described above. In addition, the program may be a so-called differential file (differential program) that implements the functions described above in combination with other programs already stored in the storage 93.

[0058] According to the above-described aspects of this disclosure, the work machine can operate quickly after startup, even while being equipped with a fuel cell.

[0059] 1...Working machine 110...Traveling body 120...Slewing body 130...Working machine 131...Boom 131C...Boom cylinder 132...Arm 132C...Arm cylinder 133...Attachment 133C...Attachment cylinder 134...Travel motor 140...Operator's cab 142...Control device 143...Power switch 145...Main control unit 150...Machine room 20...Fuel cell system 21...Fuel cell module 211...Fuel cell 212...Power converter 213...Auxiliary equipment 214...Fuel cell control unit 22...Energy storage module 221...Energy storage unit 222...Power converter 30...Drive system 31...Hydraulic drive module 311...Inverter 312...Electric pump motor 313...Hydraulic pump 314...Hydraulic actuator 32...Slewing module 321...Inverter 322...Electric slewing motor 90...Computer 91...Processor 92...Main memory 93...Storage 94...Interface B...Busline

Claims

1. A work machine comprising a fuel cell, an energy storage device, a work machine driven by electric power, and a control device, wherein the control device initiates startup control, which causes the energy storage device to output power and restricts the operation of the work machine before the fuel cell has finished starting up.

2. The work machine according to claim 1, wherein the control device notifies the operator that the operation of the work machine is restricted.

3. The work machine according to claim 1, wherein the control device, after the fuel cell has finished starting up, outputs power from the fuel cell and releases the restriction on the operation of the work machine.

4. The work machine according to claim 3, wherein the control device increases the upper limit of the output of the actuator that drives the work machine at a predetermined rate after the fuel cell has finished starting up.

5. The work machine according to claim 1, comprising a plurality of fuel cells including the fuel cell, wherein the control device starts at least a portion of the plurality of fuel cells at different timings, and limits the upper limit of the output of the actuator that drives the work machine to an amount corresponding to the number of started fuel cells.

6. A control method for a work machine comprising a fuel cell, an energy storage device, and a work machine driven by electric power, wherein the control method initiates startup control, which involves outputting power from the energy storage device and limiting the operation of the work machine before the fuel cell has finished starting up.

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