Electric work machine

Abstract

Provided is an electric work machine that is characterized by comprising: a fuel cell 1; a secondary cell 5; a driving motor 2 driven by electric power supplied from the fuel cell 1 or the secondary cell 5; an electric fan 16 for assisting in the warming-up of the fuel cell 1; and a controller 9 for controlling the electric fan 16, wherein the controller 9 drives the electric fan 16 such that surplus power generated by the fuel cell 1 is consumed when warming up the fuel cell 1 during startup. This configuration makes it is possible to provide an electric work machine capable of consuming surplus power even when surplus power during warm-up of the fuel cell cannot be charged to the secondary cell.

Description

electric work machine

[0001] The present invention particularly relates to an electric work machine that is equipped with a fuel cell and a secondary battery and operates using power supplied from them.

[0002] In recent years, environmentally friendly fuel cells have been commercialized and installed in automobiles and other vehicles. A well-known example of a system equipped with a fuel cell in the mobility field is a system that uses a fuel cell and a secondary cell (battery) to drive a motor using the power output from these. When the fuel cell is started up at a low temperature, it warms up to increase its own temperature in order to improve power generation efficiency. During warm-up, the fuel cell generates a small amount of power (hereafter referred to as surplus power) that is insufficient to drive the motor. In this case, some means must be used to consume the surplus power.

[0003] Patent Document 1 discloses a fuel cell system that includes a hydrogen tank that stores hydrogen mixed with an odorant, a stirring means that stirs the odorant and hydrogen in the hydrogen tank, a fuel cell that generates electricity by receiving a supply of hydrogen gas from the hydrogen tank, and a means for driving the stirring means with surplus electricity generated when the fuel cell is warmed up.

[0004] JP 2007-134246 A

[0005] In addition to providing a dedicated stirring means as in Patent Document 1, a method of consuming surplus power by charging a secondary battery is also conceivable. However, when the secondary battery has a relatively high SOC (State of Charge), surplus power cannot be charged, so the fuel cell must be warmed up while limiting the amount of power generated. As a result, it takes a long time to start up the fuel cell. In the case of electrically powered work machines, the operator is often unable to leave the machine while power is being generated. Therefore, the long warm-up time required impairs usability.

[0006] An object of the present invention is to provide an electric work machine that can consume surplus power even when the surplus power generated during warm-up of a fuel cell cannot be charged into a secondary battery.

[0007] In order to solve the above problems, the present invention provides an electric work machine including a fuel cell, a secondary battery, a drive motor driven by power supplied from the fuel cell or the secondary battery, a warm-up assist device that assists in warming up the fuel cell, and a controller that controls the warm-up assist device, wherein the controller drives the warm-up assist device when warming up the fuel cell at startup to consume surplus power generated by the fuel cell. In this case, it is possible to provide an electric work machine that can consume surplus power even when the surplus power cannot be charged into the secondary battery.

[0008] Here, for example, the vehicle may further include a heat exchanger for dissipating exhaust heat, and the warm-up assist device may be an electric fan provided in the heat exchanger. In this case, air from inside the vehicle body may be used to assist warming up the fuel cell. For example, the controller may drive the electric fan in a direction that expels air from the inside of the vehicle body to the outside of the vehicle body when warming up the fuel cell at startup, and drive the electric fan in a direction that draws air from the outside of the vehicle body into the inside of the vehicle body after warming up the fuel cell is complete. In this case, the operation of the electric fan may be changed so that air from the inside of the vehicle body is used to assist warming up the fuel cell and that the heat exchanger is cooled after warming up the fuel cell is complete. Furthermore, for example, the controller may change the rotation speed of the electric fan depending on the amount of power generated during warm-up of the fuel cell. In this case, the electric fan may be caused to consume power depending on the amount of surplus power. Furthermore, for example, when warming up the fuel cell at startup, if the amount of power stored in the secondary battery is less than a predetermined threshold, the controller may not drive the electric fan and may instead supply surplus power generated by the fuel cell to the secondary battery. In this case, when the remaining power of the secondary battery is low and charging is possible, the surplus power can be used to charge the secondary battery, and when the remaining power of the secondary battery is high and charging is not possible, the surplus power can be consumed by an electric fan. Furthermore, for example, a monitor provided in the driver's seat is further provided as a device for displaying the operating status of the fuel cell and the warm-up assist device. In this case, the operator can be notified of the operating status of the fuel cell and the warm-up assist device. Furthermore, for example, the warm-up assist device is a heater that warms the fuel cell. In this case, the heat generated by the heater can assist in warming up the fuel cell. Furthermore, for example, when performing a drainage process when the fuel cell is stopped, the controller drives the warm-up assist device to consume the surplus power generated by the fuel cell. In this case, the surplus power can also be consumed during the drainage process.

[0009] According to the present invention, it is possible to provide an electric work machine that can consume surplus power even when the surplus power generated during warm-up of the fuel cell cannot be charged into the secondary battery.

[0010] 1 is a diagram showing the overall configuration of an electric work machine in this embodiment. FIG. 2 is a diagram showing the configuration of a fuel cell and components connected to the fuel cell. FIG. 3 is a block diagram showing the processing when a controller controls the warming up of the fuel cell and the operation of the electric fan when starting up the hydraulic excavator. FIG. 4 is a flowchart showing the operation performed by the controller when warming up the fuel cell when starting up the hydraulic excavator. FIG. 5 is a diagram showing a time chart when warming up the fuel cell when starting up the hydraulic excavator. FIG. 6 is a flowchart showing the operation performed by the controller when draining water from the fuel cell when shutting down the hydraulic excavator. FIG. 7 is a diagram showing a time chart when draining water from the fuel cell when shutting down the hydraulic excavator. FIG. 8 is a diagram showing an indicator when surplus power is consumed. FIG. 9 is a diagram showing an indicator when surplus power is consumed.

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0012] <Explanation of the overall configuration of the electric work machine> Figure 1 is a diagram showing the overall configuration of an electric work machine in this embodiment. The electric work machine shown in the figure is a hydraulic excavator. However, the electric work machine is not limited to this and can be construction machinery such as a wheel loader, bulldozer, or crane truck. The electric work machine can also be agricultural machinery such as a felling machine, lumbering machine, tractor, forestry work vehicle, or logging machine.

[0013] FIG. 1 is a diagram of a hydraulic excavator with the upper cover removed from an upper revolving body 17, which is an example of a vehicle body. Hereinafter, left and right refer to left and right when viewing the upper revolving body 17 from above, with the front of the machine body facing upward in the figure. As shown in the figure, a fuel cell 1 is installed in the center of the upper revolving body 17, and a drive motor 2 and a connected hydraulic pump 3 are located above the fuel cell 1. The drive motor 2 is controlled by an inverter 4. A secondary battery 5 is installed on the left side of the upper revolving body 17. The drive motor 2 is driven by power supplied from the fuel cell 1 or the secondary battery 5. The secondary battery 5 is charged by power supplied from the fuel cell 1. The fuel cell 1, inverter 4, and secondary battery 5 are connected by a high-voltage cable 31. A hydrogen storage container 6 filled with high-pressure hydrogen is installed at the rear of the upper revolving body 17. Hydrogen supplied from the hydrogen storage container 6 is supplied to the fuel cell 1 through a hydrogen valve 7 and a hydrogen piping 32. An oil cooler 13, a motor / inverter radiator 14, and a fuel cell radiator 15 are installed on the right outer edge of the upper rotating body 17. The oil cooler 13 is connected to the hydraulic pump 3 and other hydraulic equipment via hydraulic piping (not shown). The motor / inverter radiator 14 is connected to a cooling water circuit (not shown) for high-voltage components such as the drive motor 2, inverter 4, and secondary battery 5. The fuel cell radiator 15 is connected to a cooling water circuit (not shown) for the fuel cell 1. An electric fan 16 is attached to each of the oil cooler 13, the motor / inverter radiator 14, and the fuel cell radiator 15. A monitor 10 is provided in the cab 8, which serves as the driver's seat, for displaying and operating various information about the hydraulic excavator. A monitor 11 and indicator lights 12 for displaying the status of the fuel cell 1 and the electric fan 16 are provided on the external cover of the hydraulic excavator. The other configurations are the same as those of conventional hydraulic excavators, so a description thereof will be omitted.

[0014] FIG. 2 is a structural diagram of the fuel cell 1 and the components connected to it. The fuel cell 1 is connected to the inverter 4, which controls the drive motor 2, the secondary battery 5, and the DC-DC converter 18 via a high-voltage cable 31. Hydrogen is supplied to the fuel cell 1 from a hydrogen storage container 6 through a hydrogen valve 7 and a hydrogen pipe 32. The hydraulic pump 3 is connected to an oil cooler 13 via a hydraulic pipe 33 for cooling. The drive motor 2, the inverter 4, and the fuel cell 1 are connected to a motor / inverter radiator 14 and a fuel cell radiator 15 via a cooling water circuit 34 for cooling each of them. The oil cooler 13, the motor / inverter radiator 14, and the fuel cell radiator 15 function as heat exchangers for dissipating exhaust heat. The oil cooler 13, the motor / inverter radiator 14, and the fuel cell radiator 15 are each equipped with an electric fan 16, which blows air into the coolant in the cooling water circuit 34 to lower the temperature of the coolant. Temperature sensors 20 are attached to the hydraulic piping 33 and the cooling water circuit 34 to monitor the temperatures. In addition to the various devices mentioned above, the controller 9 controls a start switch 19 that the operator uses to start and stop the hydraulic excavator, and monitors 10, 11 and an indicator light 12 that display various information about the hydraulic excavator. As will be described below, the controller 9 also controls the warm-up of the fuel cell 1 and the operation of the electric fan 16 when the hydraulic excavator is started.

[0015] 3 is a block diagram showing the processing performed by the controller 9 when controlling the warm-up of the fuel cell 1 and the operation of the electric fan 16 during startup of the hydraulic excavator. The controller 9 includes a per-device acceptable power calculation unit 23, a per-device power increase / decrease value calculation unit 24, and a per-device post-increase / decrease power calculation unit 25. The per-device acceptable power calculation unit 23 acquires cooling device 1 required power, cooling device 2 required power, cooling device 3 required power, and cooling device 4 required power as cooling device required power 21 for driving the cooling devices 1 to 4, which are provided in plurality on the hydraulic excavator. In this case, the cooling devices 1 to 4 are the electric fan 16. The per-device acceptable power calculation unit 23 also calculates the amount of power that can be accepted by each of the cooling devices 1 to 4 in order to consume surplus power generated when warming up the fuel cell 1 during startup of the hydraulic excavator.

[0016] The per-device power increase / decrease value calculation unit 24 obtains the power that can be accepted by the cooling devices 1 to 4 from the per-device acceptable power calculation unit 23. The per-device power increase / decrease value calculation unit 24 also obtains the surplus power 22 and the cooling priority pattern 27. The per-device power increase / decrease value calculation unit 24 then compares the amount of power that can be accepted by the cooling devices 1 to 4 with the surplus power 22, and calculates how much power each of the cooling devices 1 to 4 should consume, including the priority. The priority is calculated according to the cooling priority pattern 27 that is calculated separately. The cooling priority pattern 27 can be calculated in any manner, but can be determined, for example, according to the temperature of the cooling water used by each of the cooling devices 1 to 4. In this case, the priority is increased if the temperature of the cooling water is high, and decreased if the temperature of the cooling water is low.

[0017] The post-increase / decrease per-device power calculation unit 25 sums the cooling device required power 21 and the amount of power consumed by cooling devices 1 to 4 calculated by the per-device power increase / decrease value calculation unit 24, and calculates a post-surplus-adjustment cooling device required power 26. Here, the post-surplus-adjustment cooling device required power 26 is output as a post-surplus-adjustment cooling device 1 required power, a post-surplus-adjustment cooling device 2 required power, a post-surplus-adjustment cooling device 3 required power, and a post-surplus-adjustment cooling device 4 required power. Note that although FIG. 3 has been described assuming that there are four cooling devices, cooling devices 1 to 4, there is no restriction on the number of devices.

[0018] <Processing at Startup of Hydraulic Excavator> FIG. 4 is a flowchart showing the operations performed by the controller 9 when warming up the fuel cell 1 at startup of the hydraulic excavator. First, when the operator operates the start switch 19 to turn the key on, the controller 9 initializes the fuel cell 1 and then determines whether to warm up the fuel cell 1, as shown in step S401. The method for determining whether warming up the fuel cell 1 is necessary is not limited to the method used in this embodiment. For example, the controller 9 determines whether warming up is necessary if the temperature measured by the temperature sensor 20 is below a predetermined temperature, and whether warming up is not necessary if the temperature is equal to or higher than the predetermined temperature. That is, based on the temperature measured by the temperature sensor 20, the controller 9 determines whether warming up is necessary unless the environment is low temperature, and whether warming up is necessary if the environment is low temperature. If warming up the fuel cell 1 is necessary (Yes in step S401), the process proceeds to step S402. If warming up is not necessary (No in step S401), the process proceeds to step S408. In step S408, the controller 9 starts generating power to drive the drive motor 2. That is, when the temperature measured by the temperature sensor 20 is high, the controller 9 does not perform warm-up, but starts generating electricity to drive the drive motor 2 .

[0019] In step S402, the controller 9 determines whether or not the secondary battery 5 can be charged from its SOC. The SOC value used to determine whether or not the secondary battery 5 can be charged is set in advance. If the SOC is low and the battery 5 can be charged (Yes in step S402), the process proceeds to step S403. If the SOC is high and the battery 5 cannot be charged (No in step S402), the process proceeds to step S404. In step S403, the controller 9 warms up the secondary battery 5 while charging it with surplus power from the fuel cell 1. That is, the controller 9 charges the secondary battery 5 with surplus power generated during warm-up.

[0020] In step S404, the controller 9 determines whether or not the electric fan 16 can consume additional power using the method shown in Fig. 3. If the electric fan 16 can consume additional power (Yes in step S404), the process proceeds to step S405, and if the electric fan 16 cannot consume additional power (No in step S404), the process proceeds to step S406.

[0021] In step S405, the controller 9 determines that the electric fan 16 can receive power, and warms up the fuel cell 1 while driving the electric fan 16 to consume excess power. At this time, the controller 9 executes the excess power consumption control shown in FIG. 3 . This can also be said to mean that the controller 9 drives the electric fan 16 to consume excess power generated by the fuel cell 1 when warming up the fuel cell 1 at startup. The purpose of warming up the fuel cell 1 is to increase the coolant temperature, but the ambient air temperature is low. Therefore, when warming up the fuel cell 1 at startup, the controller 9 controls the electric fan 16 to drive in a direction that exhausts air from the inside of the upper rotating body 17 to the outside of the upper rotating body 17, rather than taking in air from the outside. If air is taken in from the outside during warm-up operation, the low-temperature air from the outside may hinder the warm-up of the fuel cell 1. On the other hand, when the electric fan 16 is driven in a direction to exhaust air from the inside of the upper rotating body 17 to the outside of the upper rotating body 17, the internal air, which is warmer than the outside air, is circulated, thereby assisting in warming up the fuel cell 1. In this case, the electric fan 16 functions as a warm-up auxiliary device that assists in warming up the fuel cell 1. After warming up the fuel cell 1 is completed, the controller 9 controls the electric fan 16 to drive in a direction to draw air from the outside of the upper rotating body 17 into the inside of the upper rotating body 17. That is, the controller 9 controls the rotation direction of the electric fan 16 to be reversed during warm-up operation and after the warm-up operation is completed. After warming up the fuel cell 1 is completed, exhaust heat generated by the oil cooler 13, motor / inverter radiator 14, and fuel cell radiator 15 needs to be discharged to the outside. Therefore, the electric fan 16 is driven to draw in low-temperature air from the outside of the upper rotating body 17 and send it inside.

[0022] In step S406, power generation by the fuel cell 1 is limited, and warm-up is performed at ultra-low power generation. In this case, there is no electric fan 16 to consume excess power. Therefore, the fuel cell 1 warms up while generating ultra-low power. This allows excess power to be kept very low, but warm-up takes a long time. Once warm-up is complete in steps S403, S405, and S406, the process proceeds to step S407, where the controller 9 controls the fuel cell 1 to start generating power to drive the drive motor 2. In the embodiment described above, the electric fan 16 is used as a warm-up assistance device to assist in warming up the fuel cell 1. However, a heater to heat the fuel cell 1 can also be used instead of or in addition to the electric fan 16. In this case, the heat generated by the heater can assist in warming up the fuel cell 1.

[0023] FIG. 5 is a time chart showing the warm-up of the fuel cell 1 when starting up the hydraulic excavator. In FIG. 5, the horizontal axis represents time. First, at time t11, the operator operates the start switch 19 to turn the key on. Then, at time t12, the fuel cell 1 starts up, but in a low-temperature environment, the fuel cell 1 is warmed up. In this case, at time t13, the fuel cell 1 starts generating a small amount of power for warm-up. This generates surplus power. At this time, if the remaining capacity of the secondary battery 5 is equal to or greater than the chargeable threshold, the secondary battery 5 cannot be charged. Therefore, after time t12, the rotation speed of the electric fan 16 is increased to consume the surplus power. On the other hand, when warming up the fuel cell 1 at startup, if the amount of charge stored in the secondary battery 5 is less than a predetermined threshold, the controller 9 does not drive the electric fan 16 and instead supplies the surplus power generated by the fuel cell 1 to the secondary battery 5. The electric fan 16 rotates in a direction that exhausts air from the inside of the upper rotating body 17 to the outside. Here, the electric fan 16 rotates in the opposite direction to normal rotation, which is illustrated as reverse rotation in FIG. 5 . The rotation speed of the electric fan 16 may be varied in response to changes in the amount of power generated by the fuel cell 1. This means that the controller 9 changes the rotation speed of the electric fan 16 in response to the amount of power generated during warm-up of the fuel cell 1. Then, at time t14, warm-up of the fuel cell 1 is completed. After time t14, the electric fan 16 rotates in a direction that draws air from the outside of the upper rotating body 17 to the inside. That is, the electric fan 16 rotates in the normal direction. Here, the electric fan 16 rotates in the normal direction, which is illustrated as forward rotation in FIG. 5 . Then, at time t15, the fuel cell 1 starts generating power to drive the drive motor 2, and the drive motor 2 begins to operate.

[0024] <Processing when shutting down the hydraulic excavator> Because the fuel cell 1 generates water when generating electricity, there is a risk of it freezing and being damaged in a sub-zero environment. To prevent this, when the fuel cell 1 is stopped at low temperatures, a drainage process is performed in which the water inside the fuel cell 1 is drained before the fuel cell 1 is stopped. Even at this time, the fuel cell 1 needs to consume surplus power to generate electricity. In this embodiment, when the SOC of the secondary battery 5 is high during the drainage process and the generated power cannot be used for charging, the electric fan 16 is operated to consume the surplus power. This can also be said to mean that the controller 9 drives the electric fan 16 to consume the surplus power generated by the fuel cell 1 when performing the drainage process when the fuel cell 1 is stopped.

[0025] FIG. 6 is a flowchart showing the operation of the controller 9 when draining the fuel cell 1 at the end of the hydraulic excavator operation. First, when the operator operates the start switch 19 to turn the key off, the controller 9 determines whether or not there is a draining request for the fuel cell 1, as shown in step S601. The method for determining whether or not there is a draining request for the fuel cell 1 is not limited to this embodiment. For example, the controller 9 determines whether or not there is a draining request for the fuel cell 1 if the temperature measured by the temperature sensor 20 is below a predetermined temperature, and whether or not there is a draining request if the temperature is equal to or higher than the predetermined temperature. That is, based on the measurement by the temperature sensor 20, the controller 9 does not perform the draining process unless the environment is a low temperature, and performs the draining process if the environment is a low temperature. If there is a draining request (Yes in step S601), the process proceeds to step S602. If there is no draining request (No in step S601), the process proceeds to step S608. In step S608, the controller 9 shuts down the fuel cell 1. That is, if the temperature measured by the temperature sensor 20 is high, the controller 9 stops the fuel cell 1 without performing the draining process.

[0026] In step S602, the controller 9 determines whether charging is possible from the SOC of the secondary battery 5. If the SOC is low and charging is possible (Yes in step S602), the process proceeds to step S603, and if the SOC is high and charging to the secondary battery 5 is not possible (No in step S602), the process proceeds to step S604. In step S603, the controller 9 performs the drainage process while charging the secondary battery 5. That is, the controller 9 charges the secondary battery 5 with surplus power generated when performing the drainage process.

[0027] In step S604, the controller 9 determines whether or not the electric fan 16 can consume additional power. The determination method is the same as that in step S404 of Fig. 4, and the controller 9 performs the determination by the method shown in Fig. 3. If the electric fan 16 can consume additional power (Yes in step S604), the process proceeds to step S605, and if the electric fan 16 cannot consume additional power (No in step S604), the process proceeds to step S606.

[0028] In step S605, the controller 9 performs drainage processing for the fuel cell 1 and consumes excess power by driving the electric fan 16. At this time, in order to prevent a temperature rise after the key is turned off, the electric fan 16 rotates in a direction that draws outside air into the upper rotating body 17. In other words, unlike in the case of warming up, the electric fan 16 rotates in the normal direction and is not reversed.

[0029] In step S606, power generation by the fuel cell 1 is limited, and the drainage process is carried out at ultra-low output. In this case, there is no electric fan 16 that consumes excess power. Therefore, the fuel cell 1 performs the drainage process while generating power at ultra-low output. This allows the excess power to be kept very low, but the drainage process takes a long time. Once the drainage process is completed in steps S603, S605, and S606, the process proceeds to step S607, and the controller 9 shuts down the fuel cell 1.

[0030] FIG. 7 is a time chart showing the process of draining the fuel cell 1 when the hydraulic excavator is shut down. In FIG. 7, the horizontal axis represents time. First, at time t21, the operator operates the start switch 19 to turn the key off. At this time, the amount of power generated by the fuel cell 1 temporarily decreases. If it is determined that draining is necessary, the fuel cell 1 begins the draining process at time t22. From time t22 onwards, the fuel cell 1 generates power for the draining process. This generates surplus power. At this time, if the remaining capacity of the secondary battery 5 is equal to or greater than the chargeable threshold, the secondary battery 5 cannot be charged. Therefore, from time t22 onwards, the rotation speed of the electric fan 16 is increased to consume the surplus power. Thereafter, at time t23, the draining process of the fuel cell 1 is completed. Then, at time t24, the fuel cell 1 is shut down.

[0031] <Display when surplus power is being consumed> Figures 8 and 9 are diagrams showing the displays when surplus power is being consumed. Of these, Figure 8 shows a case where a monitor 10 inside the cab 8 is used as the display. Also, Figure 9 shows a case where a monitor 11 provided on the side or rear of the machine is used as the display. As shown in the figures, the monitors 10 and 11 display the message "FC power generation in progress" to notify the operator that the fuel cell 1 is generating power, and the message "FAN rotating" to notify the operator that the electric fan 16 is rotating.

[0032] This is displayed, for example, in step S405 of Fig. 4, when excess power is consumed by warming up the fuel cell 1 and driving the electric fan 16. Since operation is restricted until the warming up of the fuel cell 1 is complete, displaying this message on the monitor 10 can notify the operator of the operational restrictions. Here, the monitor 10 functions as a device that displays the operating status of the fuel cell 1 and the electric fan 16. Also, displaying this message on the monitor 11 can notify nearby workers of the operational restrictions.

[0033] When surplus power is being generated by the fuel cell 1, an indicator light 12 provided on the top, side, or rear of the vehicle may be turned on. The indicator light 12 may be, for example, a rotating light. This prevents workers from getting an electric shock when touching the vehicle during maintenance, etc.

[0034] REFERENCE SIGNS LIST 1 fuel cell, 2 drive motor, 3 hydraulic pump, 4 inverter, 5 secondary battery, 8 cab, 9 controller, 10, 11 monitor, 13 oil cooler, 14 motor / inverter radiator, 15 fuel cell radiator, 16 electric fan, 17 upper rotating body

Claims

1. An electrically powered working machine comprising: a fuel cell; a secondary battery; a drive motor driven by power supplied from the fuel cell or the secondary battery; a warm-up assist device that assists in warming up the fuel cell; and a controller that controls the warm-up assist device, wherein the controller drives the warm-up assist device to consume surplus power generated by the fuel cell when warming up the fuel cell at startup.

2. An electric working machine according to claim 1, further comprising a heat exchanger for discharging exhaust heat, wherein the warm-up assistance device is an electric fan provided in the heat exchanger.

3. The electric working machine described in claim 2, characterized in that the controller drives the electric fan in a direction to exhaust air from inside the vehicle body to outside the vehicle body when warming up the fuel cell at startup, and drives the electric fan in a direction to take air from outside the vehicle body into the vehicle body when warming up the fuel cell has completed.

4. The electric working machine according to claim 2, wherein the controller changes the rotation speed of the electric fan in accordance with the amount of power generated during warm-up of the fuel cell.

5. The electric working machine described in claim 2, characterized in that when warming up the fuel cell at startup, if the amount of electricity stored in the secondary battery is less than a predetermined threshold, the controller does not drive the electric fan and instead supplies surplus electricity generated by the fuel cell to the secondary battery.

6. The electric working machine according to claim 1, further comprising a monitor provided in the driver's seat as a device for displaying the operating status of the fuel cell and the warm-up auxiliary device.

7. The electric working machine according to claim 1, wherein the warm-up assistance device is a heater that warms the fuel cell.

8. The electric working machine described in claim 1, characterized in that the controller drives the warm-up auxiliary device to consume surplus electricity generated by the fuel cell when performing drainage treatment when the fuel cell is stopped.

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