Work vehicle

Abstract

To enable starting and charging processes to be performed under appropriate conditions in a fuel cell-powered work vehicle.SOLUTION: A work vehicle includes a fuel cell, a tank for storing hydrogen gas to be supplied to the fuel cell, a power storage device capable of storing power from the fuel cell, an electric motor driven by power from the fuel cell or the power storage device, a transmission device for transmitting the power of the electric motor to a work device, and a control device that executes a start-up and charging process to start the fuel cell and charge the power storage device, the start-up and charging process is executed on the condition that the charging state of the power storage device is checked before operating the work device.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a work vehicle driven by a fuel cell.

Background Art

[0002] Patent Document 1 describes a fuel cell vehicle including a fuel cell system, a battery, a drive device that generates traveling power by receiving power from at least one of the fuel cell system and the power storage device, and a charging device that performs external charging for charging the power storage device with power from an external power source outside the vehicle. In the fuel cell vehicle of Patent Document 1, when the state of charge (SOC) of the battery is lower than a predetermined value and external charging is not performed when the system is stopped, a startup and charging process for starting the fuel cell and charging the battery is executed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, when the fuel cell vehicle is a work vehicle that performs, for example, agricultural work, it is not assumed under what conditions the startup and charging processes should be executed. In view of such conventional problems, an object of the present disclosure is to enable a startup and charging process to be performed under appropriate conditions in a work vehicle driven by a fuel cell.

Means for Solving the Problems

[0005] A work vehicle according to an aspect of the present disclosure includes a fuel cell, a tank for storing hydrogen gas supplied to the fuel cell, a power storage device capable of storing power from the fuel cell, an electric motor driven by power from the fuel cell or the power storage device, a transmission device for transmitting the power of the electric motor to a work device, and a control device for executing a startup and charging process for starting the fuel cell and charging the power storage device. The startup and charging process is executed on the condition that the state of charge of the power storage device is confirmed before operating the work device.

[0006] Embodiments of the present disclosure can be implemented by an apparatus, a system, a method, an integrated circuit, a computer program, or a non-transitory computer-readable recording medium, or any combination thereof. The nature of the recording medium may be either volatile or non-volatile. The apparatus may be composed of a plurality of individual apparatuses. When composed of a plurality of individual apparatuses, they may be arranged in one housing or separated and arranged in two or more separate housings.

Advantages of the Invention

[0007] According to the present disclosure, in a work vehicle driven by a fuel cell, the startup and charging processes can be performed under appropriate conditions.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] <Summary of Embodiments of the Present Disclosure> The summary of the embodiments of the present disclosure will be listed and described below. (1) The work vehicle according to this embodiment includes a fuel cell, a tank for storing hydrogen gas supplied to the fuel cell, a power storage device capable of storing electric power from the fuel cell, an electric motor driven by electric power from the fuel cell or the power storage device, a transmission device for transmitting the power of the electric motor to a work device, and a control device for executing a startup and charging process for starting the fuel cell and charging the power storage device, and the startup and charging process is executed on the condition that the state of charge of the power storage device is confirmed before operating the work device.

[0010] According to the work vehicle of this embodiment, since the startup and charging processes are executed on the condition that the state of charge of the power storage device is confirmed before operating the work device, the startup and charging processes are not executed when the work device is operating. For this reason, for example, the startup and charging processes are executed only when the work vehicle is stored in a warehouse for a long time and the work device is not operating. Therefore, in a work vehicle driven by a fuel cell, the startup and charging processes can be performed under appropriate conditions.

[0011] (2) In the work vehicle of (1) above, the confirmation of the state of charge may be executed on the condition that the fuel cell is stopped. The reason is that the startup and charging process of starting the fuel cell and performing charging is premised on the fuel cell being stopped.

[0012] (3) In the work vehicle of (2) above, the control device may execute the startup and charging process when the state of charge of the power storage device is equal to or less than a predetermined value. In this way, it is possible to prevent the state of charge of the charging device from becoming equal to or less than a predetermined value (for example, 20%).

[0013] (4) In the work vehicle of (3) above, the control device may execute a notification process to the operator when charging of the power storage device cannot be completed. In this way, it is possible to notify the operator of the necessity of hydrogen gas filling.

[0014] (5) In the work vehicle of (1) to (4) above, the start-up and charging processes may be executed on the condition that the fuel cell has stopped for a predetermined period. In this way, by setting the period during which it is estimated that the charge state of the charging device falls below the threshold due to self-discharge to the above-mentioned predetermined period, the execution frequency of the start-up and charging processes can be set to an appropriate value.

[0015] (6) In the work vehicle of (1) to (4) above, the start-up and charging processes may be executed on the condition that a server that creates a work plan for the work vehicle or an execution command is received from the operator's terminal device. In this case, since the start-up and charging processes are performed on the condition that an execution command is received, the operator can execute the start-up and charging processes at a desired frequency.

[0016] (7) In the work vehicle of (1) to (4) above, the control device may execute the hydrogen gas filling process for the hydrogen gas tank based on the rest period of the work vehicle until work resumes. In this case, for example, by adopting the rest period set from a work plan or the like, the hydrogen gas filling process can be performed at an accurate time.

[0017] (8) In the work vehicle of (1) to (4) above, the power storage device includes a first battery with a higher output voltage and a second battery with a lower output voltage, and the start-up and charging processes may target at least one of the first and second batteries. In this way, the start-up and charging processes can be executed for at least one of the first battery and the second battery.

[0018] <Details of Embodiments of the Present Disclosure> Hereinafter, with reference to the drawings, details of embodiments of the present disclosure will be described. Note that at least a part of the embodiments described below may be arbitrarily combined.

[0019] 〔Overall Structure of the Work Vehicle〕 FIG. 1 is a perspective view showing an example of the overall structure of the work vehicle 1. FIG. 2 is a right side view of the work vehicle 1 with some exterior parts (such as the bonnet 34 and the cover 111) removed. As shown in FIGS. 1 and 2, the work vehicle 1 is a vehicle used for agricultural work, specifically a tractor. However, the work vehicle 1 is not limited to a tractor and may be a moving body such as an agricultural machine, a construction machine, and a utility vehicle.

[0020] The work vehicle 1 includes a vehicle body 11, a traveling device 12 that supports the vehicle body 11, a driver's seat 15, a cabin 16, and the like. The vehicle body 11 includes a chassis 41, a bonnet 34, a cover 111, a cabin 16, and a fender for the rear wheel 12B. Specifically, on the chassis 41 of the vehicle body 11, a bonnet 34 and a cover 111 are mounted in order from the front to the rear, and a cabin 16 is disposed behind the cover 111.

[0021] The work vehicle 1 further includes a tank unit 21 having a plurality of tanks 13 (see FIG. 2) for storing fuel, and a drive device 14 driven by the stored fuel. The fuel is a liquid or a gas, such as hydrogen, methane, carbon monoxide (CO), etc. In this embodiment, the tank 13 stores hydrogen gas. Therefore, the work vehicle 1 is a fuel cell vehicle (FCV: Fuel Cell Vehicle), and travels using the electric power generated by the chemical reaction of hydrogen and oxygen in the fuel cell 24 as an energy source. The fuel cell 24 may generate electric power using methane or carbon monoxide (CO).

[0022] The drive device 14 includes a fuel cell 24, a battery unit 30, and an electric motor 31 (see FIG. 3; hereinafter also referred to as the "motor 31"). The battery unit 30 incorporates at least one battery pack 30A (see FIG. 4) that stores the output power of the fuel cell 24. The work vehicle 1 has a hydrogen gas pipe 22. Hydrogen gas is supplied from a gas filling port 52 (see FIG. 4) connected to the end of the pipe 22 and filled into each tank 13. The hydrogen gas in the tank 13 is supplied to the fuel cell 24 through the pipe 22.

[0023] The cab 16 is a compartmented driver's cab having front pillars, rear pillars, and a roof. The front pillars are arranged on the left and right sides in front of the driver's seat 15, and the rear pillars are arranged on the left and right sides behind the driver's seat 15. Instead of the cab 16, the work vehicle 1 may have a canopy or a rollover protective structure (ROPS). When the work vehicle 1 does not mount the cab 16, the tank unit 21 is arranged above the driver's seat 15 by a mounting frame 17 described later.

[0024] The traveling device 12 is composed of front wheels 12A and rear wheels 12B. Both of these are arranged symmetrically with respect to the vehicle body 11. One or both of the front wheels 12A and the rear wheels 12B rotate by the power of the motor 31. One or both of the wheels 12A, 12B (drive wheels) that rotate by the power of the motor 31 may be crawlers (endless tracks).

[0025] As shown in FIG. 2, on the front wheel 12A corresponding portion of the chassis 41, a first radiator 48, a fuel cell 24, and a second radiator 49 are mounted in order from the front side to the rear side. The first radiator 48 and the fuel cell 24 are covered by a bonnet 34, and the second radiator 49 is covered by a cover 111.

[0026] As shown in FIG. 1, the upper surface of the cover 111 is higher than the uppermost end of the bonnet 34, but lower than the uppermost end of the steering of the driver's seat 15. Further, the rear end portion of the bonnet 34 is located at a position lower than the cover 111, and the upper surface of the bonnet 34 is formed in a tapered shape that gradually becomes lower from the rear end portion toward the front end portion. For this reason, it has a structure that hardly obstructs the forward view from the operator sitting in the driver's seat 15.

[0027] 〔Internal Structure of the Work Vehicle〕 FIG. 3 is a perspective view showing an example of the internal structure of the work vehicle 1. As shown in FIG. 3, the chassis 41 constituting the vehicle body 11 is made of a steel frame having a long shape in the front-rear direction, and has a front frame 32 and a transmission case 33. The transmission case 33 is connected to the rear portion of the front frame 32, and the framework of the vehicle body 11 is formed from the transmission case 33 and the front frame 32.

[0028] A mounting frame 17 for arranging the tank unit 21 above the cabin 16 is connected to the chassis 41. The mounting frame 17 includes a substantially rectangular ceiling frame 17A whose front-rear direction is longer than the left-right direction, a plurality of pillars 17B that support the ceiling frame 17A from below, and a pair of left and right reinforcing frames 17C connected to the front end portion of the ceiling frame 17A.

[0029] The tank unit 21 is connected to the ceiling frame 17A in a horizontally placed state. As shown in FIG. 2, the ceiling frame 17A is located at a position higher than the roof of the cabin 16. Therefore, the tank unit 21 is arranged above the roof of the cabin 16. The reinforcing frame 17C is a reinforcing diagonal member that inclines downward from the front end portion of the ceiling frame 17A to the front frame 32. Therefore, the front-rear rigidity of the mounting frame 17 is enhanced as compared with the case where the ceiling frame 17A and the tank unit 21 are supported only by the pillars 17B.

[0030] A support frame 37 for supporting the battery unit 30 on the vehicle body 11 is connected to the chassis 41 of the work vehicle 1. Specifically, a motor 31 is mounted on the front frame 32 of the chassis 41, and a support frame 37 is attached to a portion of the front frame 32 corresponding to the motor 31. The support frame 37 is made of, for example, a metal frame member and is attached in a cantilever state so as to protrude to the right from the front frame 32.

[0031] The transmission case 33 located behind the motor 31 has a power transmission mechanism inside. The power transmission mechanism includes a transmission, a clutch, and a differential gear, and decelerates or accelerates the rotation of the output shaft of the motor 31 and transmits it to the traveling device 12. The power transmission mechanism inside the transmission case 33 includes a branching mechanism that outputs a part of the power of the motor 31 to the PTO shaft 334 (see FIG. 4). The PTO shaft 334 is an output shaft that protrudes rearward from the transmission case 33.

[0032] A connecting device 44 (see FIG. 2), which is constituted by, for example, a three-point link mechanism, is attached to the transmission case 33 for connecting a working device 335 (see FIG. 4, also referred to as an "implement") for performing a desired agricultural operation behind the vehicle body 11. The three-point link mechanism can be constituted by, for example, an upper arm 44A protruding rearward from the transmission case 33 and a pair of left and right lower arms 44B. The working device 335 is, for example, a tiller and a baler.

[0033] The rotational motion of the PTO shaft 334 is transmitted to the input shaft of the working device 335 connected to the connecting device 44, for example, during the driving of the traveling device 12. Therefore, the work vehicle 1 can drive the working device 335 by the power of the motor 31 while traveling on a farm field or the like.

[0034] 〔Functional Configuration of Work Vehicle〕 FIG. 4 is a block diagram showing an example of the functional configuration of the work vehicle 1. As shown in FIG. 4, the functional system of the work vehicle 1 includes a fuel system FS, a power system PS, and a temperature control system TS.

[0035] The components of the fuel system FS include at least one tank 13, a valve unit 51, etc. The components of the temperature control system TS include a plurality of radiators 48, 49, an air conditioner 50, etc. The components of the power system PS include a fuel cell 24, a boost circuit 61, an inverter 62, a motor 31, a transmission case 33, DC / DC converters 64, 65, and a battery unit (hereinafter also referred to as the "first battery") 30, etc.

[0036] The tank 13 is connected to pipes 22A, 22B via the valve unit 51. The pipe 22A is a gas pipe connecting the gas filling port 52 and the valve unit 51, and guides the hydrogen gas introduced into the filling port 52 to the tank 13. The pipe 22B is a gas pipe connecting the fuel cell 24 and the valve unit 51, and guides the hydrogen gas stored in the tank 13 to the fuel cell 24. A pressure sensor 53 for calculating the filling amount of hydrogen gas is provided in the pipe 22B.

[0037] The valve unit 51 includes a casing, an on-off valve and a pressure reducing valve housed inside the casing, etc. The valve unit 51 guides the hydrogen gas in the tank 13 to the fuel cell 24 while adjusting the flow rate by switching and controlling at least one valve. The motor 31 has a rotor and a stator having a plurality of coils, and drives the output shaft at a predetermined torque and rotational speed. For example, only one motor 31 is mounted on the work vehicle 1, and the output shaft of the motor 31 is coupled to the transmission case 33.

[0038] A plurality of motors 31 may be mounted. For example, when providing two types of motors 31 for the front wheels 12A and the rear wheels 12B, the power of each motor 31 may be output to the front wheels 12A and the rear wheels 12B respectively. The power transmission mechanism of the transmission case 33 outputs all or part of the power of the motor 31 to the traveling device 12. Also, when operating the work device 335, the power transmission mechanism also outputs the power of the motor 31 to the PTO shaft 334.

[0039] The fuel cell 24 is, for example, a battery module configured by arranging a plurality of single cells each having a positive electrode and a negative electrode in parallel in a stacked state. The fuel cell 24 aggregates the electric power generated by each single cell and generates the electric power necessary for driving the electric motor 31. The fuel cell 24 is connected to the second radiator 49 through the refrigerant flow path H2. That is, the electrodes are adjusted to a predetermined temperature by the coolant circulated from the second radiator 49. Thereby, the fuel cell 24 can maintain high power generation efficiency.

[0040] The fuel cell 24 is electrically connected to the input side of the boost circuit 61, and the output side of the boost circuit 61 is electrically connected to the DC side of the inverter 62. The boost circuit 61 boosts the voltage input from the fuel cell 24 and outputs it to the inverter 62 and the battery unit 30. The inverter 62 is electrically connected to the motor 31. The inverter 62 converts the DC input from the boost circuit 61 into three-phase AC and outputs it to the motor 31. Therefore, the electric power generated by the fuel cell 24 is boosted and converted into AC and transmitted to the motor 31.

[0041] The battery unit 30 is a power storage device that absorbs load fluctuations of the fuel cell 24. Specifically, the battery unit 30 temporarily charges the electric power supplied from the boost circuit 61 and discharges it during high load to supply driving power to the motor 31 to the inverter 62. The battery unit 30 includes a battery pack 30A and a monitoring unit 30B. The battery pack 30A includes at least one cell. The cell is a charge-discharge type such as a lithium-ion battery cell, for example. The output voltage of the battery unit 30 is, for example, 24V.

[0042] The monitoring unit 30B includes a processor that performs switching control of the operation (charging or discharging) of the battery pack 30A and measurement of the state of charge (for example, SOC). The monitoring unit 30B holds, for example, an SOC-OCV curve that defines the correspondence between the open circuit voltage and the SOC of the battery pack 30A. The processor of the monitoring unit 30B can measure the SOC of the battery pack 30A based on the OCV value detected by a voltage sensor (not shown) and the curve.

[0043] The work vehicle 1 has a plurality of electrical components that operate at a voltage lower than that of the motor 31. DC power stepped down by a step-down circuit is supplied to these electrical components. The plurality of electrical components include, for example, an auxiliary battery (hereinafter also referred to as "second battery") 63, radiators 48, 49, and an air conditioner 50. The step-down circuit is, for example, a plurality of DC / DC converters 64, 65 (hereinafter also referred to as "first converter 64" and "second converter 65") with different output voltages.

[0044] The first converter 64 steps down the DC voltage input from the boost circuit 61 to a first voltage (for example, 12 volts) and supplies it to the auxiliary battery 63, the air conditioner 50, etc. The second converter 65 steps down the DC voltage input from the boost circuit 61 to a second voltage (for example, 24 volts) and supplies it to the radiators 48, 49. The inverter 62 and both converters 64, 65 are disposed at a portion of the chassis 41 corresponding to the driver's seat 15. Note that the second voltage of the second converter 65 may be supplied to the battery unit 30.

[0045] As described above, the first radiator 48 is disposed in front of the fuel cell 24, and the second radiator 49 is disposed behind the fuel cell 24 (see FIG. 2). These radiators 48, 49 constitute a cooling system that cools electrical components such as the fuel cell 24, the boost circuit 61, the inverter 62, the motor 31, the first and second converters 64, 65, etc. with a coolant (refrigerant).

[0046] A cooling flow path H1 through which a coolant is circulated by a pump 66 is connected to the first radiator 48, and the coolant is cooled by heat exchange with outside air. The first radiator 48 has a first fan 35 for promoting heat exchange with outside air. The components to be cooled by the cooling flow path H1 of the first radiator 48 are electrical components (heat generating components) such as, for example, a boost circuit 61, an inverter 62, a motor 31, and first and second converters 64, 65.

[0047] A cooling flow path H2 through which a coolant is circulated by a pump 67 is connected to the second radiator 49, and the coolant is cooled by heat exchange with outside air. The second radiator 49 has a second fan 36 for promoting heat exchange with outside air. The components to be cooled by the cooling flow path H2 of the second radiator 49 are electrical components such as, for example, a fuel cell 24.

[0048] The auxiliary battery 63 is a power storage device that supplies power to a display, communication devices, etc. mounted on the driver's seat 15. The auxiliary battery 63 is, for example, a charge-discharge type lead-acid battery. The output voltage of the auxiliary battery (second battery) 63 is, for example, 12V, which is lower than the output voltage (e.g., 24V) of the battery unit (first battery) 30. The auxiliary battery 63 can also be used as an auxiliary power source that supplies power to a control device 70, which will be described later, when the fuel cell 24 is stopped.

[0049] As shown in FIG. 4, the power system PS further includes a control device 70. The control device 70 can be constituted by an ECU (Electronic Control Unit) that communicates with various electrical components by a communication protocol such as, for example, CAN (Controller Area Network). The control device 70 executes "battery management control" that targets the battery unit 30 based on the status of electrical components such as, for example, the fuel cell 24 and the battery unit 30. Hereinafter, the content of the battery management control will be described.

[0050] 〔Battery Management Control〕 FIG. 5 is a flowchart showing an example of battery management control performed by the control device 70. The definitions of the parameters described in FIG. 5 are as follows.

[0051] (Parameter Definition) SF: Data representing the "status of the fuel cell 24". The types of the status SF include off (stopped) and on (operating). The control device 70 acquires the status SF by, for example, CAN communication with an ECU (not shown) that controls the fuel cell 24.

[0052] SI: Data representing the "status of the working device 335". The types of the status SI include off (stopped) and on (operating). SI = off (stopped) means the stop or disconnection of the connected working device 335. SI = on (operating) means the operation of the connected working device 335. The control device 70 acquires the status SI by, for example, in-vehicle communication with an ECU mounted on the working device 335.

[0053] SOC: Data representing the "state of charge of the battery unit 30 (State Of Charge)", which is expressed as a percentage with a full charge being 100% and empty being 0%. The state of charge SOC is also referred to as the "remaining battery level". Hereinafter, the state of charge SOC may be abbreviated as "SOC". The control device 70 acquires the SOC by, for example, in-vehicle communication with the monitoring unit 30B.

[0054] GA: Data representing the "hydrogen gas filling amount in the tank 13". The filling amount GA is expressed as a percentage with a full fill being 100% and empty being 0%. The control device 70 receives the pressure value (gas pressure) of the tank 13 from the pressure sensor 53 in the pipe 22B by in-vehicle communication, for example, and calculates the filling amount GA of the tank 13 by applying the received pressure value to a predetermined filling rate calculation formula.

[0055] CH: It is a control command for instructing the execution of "startup and charging process". The startup and charging process is a process of starting the fuel cell 24 that is stopped and charging the battery unit 30. The control command CH may be composed of, for example, a CAN communication frame for instructing startup to other ECUs that control the fuel cell 24 and a CAN communication frame for instructing charging to the monitoring unit 30B.

[0056] ST: It is a control command for instructing the stop of the "operating fuel cell 24". The control command ST may be composed of, for example, a CAN communication frame for instructing stop to other ECUs that control the fuel cell 24.

[0057] NT: It is a control command for instructing "notification of gas filling to the user". The control command NT may be composed of, for example, a communication frame for instructing the transmission of a message to the user's terminal device to the TCU (Telematics Control Unit) mounted on the work vehicle 1. The user's terminal device may adopt a communication terminal such as a smartphone or a tablet terminal held by the user. Note that the user is, for example, an operator who performs work using the work vehicle 1.

[0058] (Control content) As shown in FIG. 5, the battery management control is executed every predetermined control cycle C. Specifically, for example, when all electrical components are stopped, the control device 70 starts every control cycle C by an auxiliary power source (not shown), restores CAN communication with predetermined electrical components, and performs battery management control. The control cycle C is set to a predetermined period from, for example, one day to one week, and is measured by a clock that operates by an auxiliary power source.

[0059] As shown in FIG. 5, the battery management control performed by the control device 70 includes "charge start control" (from step S11 to step S14) and "charge end control" (from step S15 to step S17).

[0060] "Charging start control" is a process that outputs a control command CH on the condition that the status SF, status SI, and SOC satisfy predetermined conditions. Specifically, the control device 70 checks whether the SOC of the battery unit 30 is equal to or less than a first threshold Th1 on the condition that the status SF of the fuel cell 24 is off (stopped) (Yes in step S11) and the status SI of the work device 335 is off (stopped) (Yes in step S12).

[0061] Thus, in the charging start process of this embodiment, the SOC of the battery unit 30 is confirmed on the condition that not only the status SF = off but also the status SI = off (stop of the connected work device 335 or non-connection of the work device 335). For this reason, for example, when it is estimated that the work vehicle 1 is stored in a shed and the work device 335 is not operating, the SOC of the battery unit 30 is confirmed. Therefore, the startup and charging processes (output of the control command CH) can be executed under appropriate conditions.

[0062] If the determination result in step ST13 is affirmative, the control device 70 outputs the control command CH (step S14). Specifically, the control device 70 transmits a communication frame instructing startup to the ECU that controls the fuel cell 24 and transmits a communication frame instructing charging to the monitoring unit 30B. Also, if the determination result in step ST13 is negative, the control device 70 ends the process without outputting the control command CH.

[0063] The first threshold Th1 can be set to, for example, 20%. The reason is that the operating range of the SOC of the battery unit 30 is usually 40% or more and 70% or less, and there is a concern about deterioration when the SOC reaches about 15%. Therefore, the SOC of the battery unit 30 should be aimed at not becoming less than at least 20%.

[0064] The "charging end process" is a process that determines whether to output a control command ST or a control command NT using the filling amount GA and the SOC as input information. Specifically, the control device 70 determines whether the battery unit 30 can be charged until the SOC becomes equal to or higher than the second threshold Th2 based on the filling amount GA and the SOC (step S15).

[0065] If the determination result in step ST15 is affirmative, the control device 70 outputs a control command ST (step S16). Specifically, the control device 70 transmits a communication frame instructing stop to the ECU that controls the fuel cell 24.

[0066] If the determination result in step ST15 is negative, the control device 70 outputs a control command NT (step S17). Specifically, the control device 70 instructs the TCU (Telematics Control Unit) to transmit a control message to the user's terminal device. In this case, the TCU generates a message indicating that gas filling is necessary and transmits it to the user's terminal device.

[0067] The second threshold Th2 can be set to a predetermined value ranging from, for example, 40% to 70%. The reason is that since the operating range of the SOC of the battery unit 30 is usually 40% or more and 70% or less, the SOC when starting the fuel cell 24 to charge the battery unit 30 should aim to reach at least 40%.

[0068] 〔First Modification Example〕 In the flowchart of FIG. 5, the process of step S11 of the charging start process may be replaced with a determination of whether the stop of the fuel cell 24 has continued for a predetermined period T1. The predetermined period T1 can be set to a period (for example, 1 to 3 months) during which it is estimated that the SOC of the battery unit 30 will fall below the first threshold Th1 due to self-discharge. In this way, the start-up and charging processes (output of the control command CH) can be performed at an appropriate frequency.

[0069] 〔Second Modification Example〕 In the flowchart of FIG. 5, it may be shifted to the determination in step S11 on the condition of receiving an execution command from a server that creates a work plan for the work vehicle 1 or a user's terminal device. In this way, since the determination in step S11 is made on the condition of receiving an execution command, the startup and charging processes (output of control command CH) can be executed at the frequency desired by the user. Note that the above server may employ a server that realizes an agricultural support system such as KSAS using the Internet cloud.

[0070] 〔Third Modification Example〕 In the above-described embodiment, the control device 70 may determine whether hydrogen gas needs to be filled into the tank 13 based on the rest period T2 of the work vehicle 1 until work restart. The rest period T2 can be set based on, for example, a work plan received from the above server. In this case, assuming that the amount of power loss due to self-discharge during the rest period T2 (for example, six months) is ΔP, the control device 70 may determine whether there is a hydrogen gas amount that can charge the battery unit 30 by ΔP or more.

[0071] Further, when the determination result of whether filling is necessary indicates that filling is necessary, the control device 70 may output the above-described control command NT. In this way, it is possible to notify the user that hydrogen gas filling is necessary.

[0072] 〔Other Modification Examples〕 The embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the rights of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope equivalent to the configurations described in the claims.

[0073] In the above-described embodiment, battery management control (FIG. 5) may be executed with at least one of the battery unit (first battery) 30 and the auxiliary battery (second battery) 63 as the target of the control command CH. By doing so, it is possible to prevent depletion of the SOC for either or both of the battery unit 30 and the auxiliary battery 63 in advance.

Explanation of Signs

[0074] 1 Work vehicle 11 Vehicle body 12 Travel device 12A Front wheel 12B Rear wheel 13 Tank (hydrogen tank) 14 Drive device 15 Driver's seat 16 Cabin 17 Mounting frame 17A Ceiling frame 17B Pillar 17C Reinforcing frame 21 Tank unit 22, 22A, 22B Pipes 24 Fuel cell 30 Battery unit (power storage device: first battery) 30A Battery pack 30B Monitoring unit 31 Electric motor (motor) 32 Front frame 33 Transmission case 34 Bonnet 35 First fan 36 Second fan 37 Support frame 41 Chassis 44 Connecting device 44A Upper arm 44B Lower arm 48 First radiator 49 Second radiator 50 Air conditioner 51 Valve unit 52 Gas filling port 53 Pressure sensor 61 Boost circuit 62 Inverter 63 Auxiliary battery (power storage device: second battery) 64 DC / DC converter (first converter) 65 DC / DC converter (second converter) 66 Pump 67 Pump 70 Control device 111 Cover 334 PTO shaft 335 Working device

Claims

1. A fuel cell, a tank for storing hydrogen gas supplied to the fuel cell, a power storage device capable of storing electric power from the fuel cell, an electric motor driven by electric power from the fuel cell or the power storage device, a transmission device for transmitting the power of the electric motor to a work device, a work vehicle comprising a control device that executes a startup and charging process for starting the fuel cell and charging the power storage device, wherein the startup and charging process is executed on the condition that the state of charge of the power storage device is checked before operating the work device.

2. The checking of the state of charge is executed on the condition that the fuel cell is stopped, according to the work vehicle described in Claim 1.

3. The control device executes the startup and charging process when the state of charge of the power storage device is equal to or less than a predetermined value, according to the work vehicle described in Claim 2.

4. The control device executes a notification process to an operator when charging of the power storage device cannot be completed, according to the work vehicle described in Claim 3.

5. The startup and charging process is executed on the condition that the fuel cell has stopped for a predetermined period, according to any one of Claims 1 to 4.

6. The startup and charging process is executed on the condition that a server for creating a work plan for the work vehicle or an execution command is received from an operator's terminal device, according to any one of Claims 1 to 4.

7. The control device executes a hydrogen gas filling process for the hydrogen gas tank based on a rest period of the work vehicle until work resumes, according to any one of Claims 1 to 4.

8. The power storage device includes a first battery with a higher output voltage and a second battery with a lower output voltage, and the startup and charging process targets at least one of the first and second batteries, according to any one of Claims 1 to 4.

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