Work vehicles

Abstract

To surely control electric power from a battery unit.SOLUTION: A work vehicle is provided with: a switching part SW, arranged in a power supply line VL1 through which an electric instrument 11 is connected to a battery unit 20, which is switched between a connection state where the electric instrument is electrically connected to the battery unit and a non-connection state where the electric instrument is not electrically connected to the battery unit; a first control part 25a (an ECU) that outputs a connection signal or a non-connection signal to the switching part SW; and a BMU 20a1 (a second control part) that outputs the connection signal or the non-connection signal to the switching part SW. When the connection signals are inputted from each of the first control part 25a and the BMU 20a, the switching part SW is brought into the connection state, so that electric power is supplied from the battery unit 20 to the electric instrument 11. When the non-connection signal is inputted from at least one of the first control part 25a and the BMU 20a1, the switching part is brought into the non-connection state, so that electric power is not supplied from the battery unit 20 to the electric instrument 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a work vehicle equipped with a battery unit and electrical equipment. [Background technology]

[0002] Conventionally, the electric work machine (e.g., excavation machine) disclosed in Patent Document 1 includes a battery unit, an inverter supplied with power from the battery unit, an electric motor supplied with AC power converted by the inverter, a pump motor driven by the electric motor, a hydraulic pump that discharges hydraulic oil by driving the pump motor, a hydraulic actuator driven by the hydraulic oil discharged by the hydraulic pump, and a system controller that controls the power supplied to the electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-190107 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described electric work machine, the system controller controls the power supply to the electric motor by turning on and off a relay disposed between the battery unit and the inverter. That is, a single system controller (controller) is configured to switch the relay (switching unit) on and off. In such a configuration in which a single controller switches the relay, there is a risk that the relay cannot be switched off and power from the battery unit cannot be stopped due to a malfunction of the controller, damage to the harness connecting the controller and the relay, a bug in the software executed by the controller, or the like.

[0005] The present invention has been made to solve the problems of the prior art, and has an object to provide a work vehicle that can reliably control the power from the battery unit. [Means for solving the problem]

[0006] A work vehicle according to one aspect of the present invention includes an electric device and a battery unit having a battery that supplies power to the electric device; a switching unit disposed on a power supply line connecting the battery and the electric device, the switching unit switching between a connected state in which the battery unit and the electric device are electrically connected and a disconnected state in which the battery unit and the electric device are not electrically connected; a first control unit that outputs a connected signal or a disconnected signal to the switching unit; and a second control unit that outputs a connected signal or a disconnected signal to the switching unit, wherein the switching unit is in the connected state when a connected signal is input from the first control unit and the second control unit, respectively, and power from the battery unit is supplied to the electric device, and is in the disconnected state when a disconnected signal is input from at least one of the first control unit and the second control unit, and power from the battery unit is supplied to the electric device. the switching unit has a first switching unit and a second switching unit that are connected in series and switch between a connected state and a disconnected state, the first control unit outputs a connection signal or a disconnected signal to the first switching unit, and the second control unit outputs a connection signal or a disconnected signal to the second switching unit, when the first switching unit and the second switching unit are in the connected state, power from the battery unit is supplied to the electric device, and when at least one of the first switching unit and the second switching unit is in the disconnected state, power from the battery unit is not supplied to the electric device, the first control unit determines that the electric device is normal when a normal signal is input from another device connected via an in-vehicle network, and outputs a connection signal to the first switching unit and an operation command signal to the second control unit, When an operation command signal is input and it is determined that the battery unit is normal, the first control unit outputs a connection signal to the second switching unit, the second switching unit having a switching unit for charging the battery and a switching unit for discharging the battery, and when it is determined that the first control unit is normal, it outputs a connection signal to the first switching unit and outputs the operation command signal to the second control unit regardless of whether the battery is being charged or discharged, and when the operation command signal from the first control unit is input and it is determined that the battery unit is normal, the second control unit outputs a connection signal to the switching unit for charging and a non-connection signal to the switching unit for discharging if the battery is being charged, and outputs a non-connection signal to the switching unit for charging and a connection signal to the switching unit for discharging if the battery is being discharged. .

[0008] The switching unit may include a first switching unit and a second switching unit connected in series to a signal line and switching between a connected state and a disconnected state, and a third switching unit arranged on the power supply line and switching between a connected state and a disconnected state, wherein the first control unit outputs a connected signal or a disconnected signal to the first switching unit, and the second control unit outputs a connected signal or a disconnected signal to the second switching unit, and the third switching unit is in the connected state when the first switching unit and the second switching unit are in the connected state and supplies power from the battery unit to the electrical device, and is in the disconnected state when at least one of the first switching unit and the second switching unit is in the disconnected state and does not supply power from the battery unit to the electrical device.

[0009] The third switching unit may be a relay having a coil unit connected to the signal line and a contact unit connected to the power supply line and switched between a connected state and a non-connected state by the coil unit. 。

[0011] When the second control unit determines that the battery unit is abnormal, it outputs a non-connection signal to the charging switching unit and the discharging switching unit, and also outputs an abnormality signal to the first control unit, and when the abnormality signal is input from the second control unit, the first control unit may output a non-connection signal to the first switching unit. The vehicle may include a vehicle body having a running device, the electrical equipment including an inverter supplied with power from the battery unit and an electric motor that drives the running device based on AC power converted by the inverter, the first control unit being a vehicle control device that controls at least the inverter, and the second control unit being a battery monitoring device that monitors and controls the battery unit.

[0012] A work vehicle according to one aspect of the present invention includes an electric device and a battery unit having a battery that supplies power to the electric device; a switching unit that is arranged on a power supply line connecting the battery and the electric device and that switches between a connection state in which the battery unit and the electric device are electrically connected and a disconnection state in which the battery unit and the electric device are not electrically connected; a first control unit that outputs a connection signal or a disconnection signal to the switching unit; and a second control unit that outputs a connection signal or a disconnection signal to the switching unit, wherein the switching unit is in the connection state when a connection signal is input from the first control unit and the second control unit, respectively, and power from the battery unit is supplied to the electric device, and is in the disconnection state when a disconnection signal is input from at least one of the first control unit and the second control unit, and power from the battery unit is not supplied to the electric device, and the switching unit has first and second switching units that are connected in series and that switch between a connection state and a disconnection state, and the first control unit outputs a connection signal or a disconnection signal to the first switching unit. the second control unit outputs a connection signal to the second switching unit, and the second control unit outputs a connection signal or a disconnection signal to the second switching unit, and when the first switching unit and the second switching unit are in the connected state, power from the battery unit is supplied to the electrical device, and when at least one of the first switching unit and the second switching unit is in the disconnected state, power from the battery unit is not supplied to the electrical device, the first control unit determines that the battery unit is normal when a normal signal is input from another device connected via an in-vehicle network, and outputs a connection signal to the first switching unit and an operation command signal to the second control unit, and when the second control unit receives the operation command signal from the first control unit and determines that the battery unit is normal, it outputs a connection signal to the second switching unit, and when the second control unit determines that the battery unit is abnormal, it outputs a disconnection signal to the second switching unit and an abnormality signal to the first control unit, and the first control unit outputs a disconnection signal to the first switching unit when the abnormality signal from the second control unit is input, The power supply includes a backup switching unit connected in parallel to the first switching unit and switching between a connected state and a non-connected state, and the first control unit outputs a connection signal to the backup switching unit when the first switching unit does not switch to the connected state and an abnormality signal is not input from the second control unit, and does not output a connection signal to the backup switching unit when the first switching unit is in the connected state. stomach.

[0013] The device may be provided with a display device, and the first control unit may, if the first switching unit does not switch to the connected state, cause the display device to display a message prompting an instruction to switch the backup switching unit to the connected state, and may output a connection signal to the backup switching unit when the first control unit receives the instruction to switch based on an operation on the display device or another operating device. [Effects of the Invention]

[0014] According to the above work vehicle, the power from the battery unit can be reliably controlled. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram showing the entire system of a work vehicle 1 (tractor). [Figure 2] 10 is a diagram showing an example of a circuit configuration in which two control units control switching of a switching unit SW. FIG. [Figure 3] FIG. 2 is a diagram showing an example of a circuit configuration of a switching unit SW. [Figure 4] 4 is a flowchart showing a battery output start process according to the first embodiment. [Figure 5] 5 is a flowchart showing a battery output stop process in the event of an abnormality according to the first embodiment. [Figure 6] FIG. 10 is a diagram illustrating an example of a circuit configuration according to a second embodiment. [Figure 7] FIG. 10 is a diagram illustrating an example of a circuit configuration of a switching unit SW according to a second embodiment. [Figure 8A] 10 is a flowchart showing a battery output start process according to a second embodiment. [Figure 8B] 10 is a flowchart showing a battery output stop process in the event of an abnormality according to the second embodiment. [Figure 9] FIG. 10 is a diagram illustrating an example of a circuit configuration of a switching unit SW according to a third embodiment. [Figure 10] 10 is a flowchart showing a battery output start process according to a third embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of a message screen according to the third embodiment. [Figure 12] FIG. 10 is a diagram illustrating an example of a circuit configuration according to a fourth embodiment. [Figure 13] FIG. 2 is a side view of the work vehicle 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [First embodiment] 13 is a side view showing one embodiment of a work vehicle 1. In this embodiment, the work vehicle 1 is a tractor. The work vehicle 1 includes a vehicle body 2. The vehicle body 2 is provided with a driver's seat 7 in which a worker sits.

[0017] In the following description of this embodiment, the direction that a worker seated in the driver's seat 7 of the work vehicle 1 faces (the direction of arrow A1 in FIG. 13) will be referred to as the forward direction, the opposite direction (the direction of arrow A2 in FIG. 13) as the rearward direction, the left side of the worker (the front side of FIG. 13) as the left side, and the right side of the worker (the back side of FIG. 13) as the right side. In addition, the horizontal direction that is perpendicular to the fore-and-aft direction of the work vehicle 1 will be referred to as the width direction. Fig. 1 is a diagram showing the entire system of a work vehicle. As shown in Figs. 1 and 13, the work vehicle 1 is equipped with a traveling device 4, a battery unit 20, an electric device 11, a transmission 10, and a connecting unit 8. The traveling device 4, the battery unit 20, the electric device 11, the transmission 10, and the connecting unit 8 are provided on a vehicle body 2. As shown in Fig. 13, the traveling device 4 is a device having front wheels 4A and rear wheels 4B that are driven to rotate, and the vehicle body 2 can travel by the traveling device 4. The front wheels 4A and rear wheels 4B may be of either a tire type or a crawler type.

[0018] The battery unit 20 is a structure that is capable of storing electricity and outputs the stored electricity. The battery unit 20 has a battery 20a inside a housing (casing). The battery 20a is capable of storing electricity and is a secondary battery such as a lithium-ion battery or a lead-acid battery. The battery 20a has a plurality of cells inside, and the plurality of cells are electrically connected in series and parallel. The battery unit 20 is connected to a charger 21 provided on the work vehicle 1. The charger 21 is a socket to which a cable that charges the battery unit 20 is connected. The battery unit 20 can be charged by power supplied from outside via the charger 21.

[0019] The electric devices 11 are devices such as electrical components that are driven by power supplied from the battery unit 20. More specifically, the electric devices 11 are directly or indirectly connected to the battery unit 20 and are devices that transmit the power supplied by the battery unit 20 or devices that operate using the power. As shown in FIG. 1 , the electric devices 11 include an electric motor 12 that is driven by power from the battery unit 20. The electric devices 11 also include, for example, an inverter 13 and a DC / DC converter 14.

[0020] The electric motor 12 is a drive source for the work vehicle 1 that is driven by the power output by the battery unit 20. The electric motor 12 rotates a drive shaft using the power supplied from the battery unit 20. The electric motor 12 is a three-phase AC synchronous motor with embedded permanent magnets. The electric motor 12 has a rotatable rotor and a stator that generates a force to rotate the rotor.

[0021] The inverter 13 is connected to the battery unit 20 and the electric motor 12. The inverter 13 is a device that drives the electric motor 12, and converts DC power supplied by the battery unit 20 into three-phase AC power and supplies it to the electric motor 12. In other words, the electric motor 12 is connected to the battery unit 20 via the inverter 13. The inverter 13 can arbitrarily change the current and voltage of the power supplied to the electric motor 12.

[0022] DC / DC converter 14 is connected to battery unit 20 and converts the voltage of the DC power supplied from battery unit 20 into a different voltage. In this embodiment, DC / DC converter 14 is a step-down converter that converts an input voltage into a lower voltage. DC / DC converter 14 supplies power to, for example, an on-board battery 15 that supplies power to electronic devices provided in work vehicle 1.

[0023] The transmission 10 is connected to the drive shaft of the electric motor 12, and the power output by the electric motor 12 is transmitted to the transmission 10, and the traveling device 4 is driven by the power whose speed has been changed by the transmission 10. The transmission 10 is provided with an output shaft (PTO shaft) 17 that outputs the power output by the electric motor 12 to the outside. The PTO shaft 17 is provided so as to protrude rearward from the rear of the vehicle body 2.

[0024] The connecting part 8 is provided on the vehicle body 2 so as to be able to swing freely, and a working device 9 can be attached and detached to the rear part of the connecting part 8. The work implements 9 are operated by power input from an external source, for example, power input from the PTO shaft 17. The work implements 9 include a tilling implement for tilling, a fertilizer spreading device for spreading fertilizer, a pesticide spreading device for spreading pesticide, a harvesting device for harvesting, a reaping device for reaping grass and the like, a spreading device for spreading grass and the like, a grass collecting device for collecting grass and the like, a forming device (roll baler) for forming grass and the like, and the like.

[0025] In the above-described embodiment, the drive shaft of the electric motor 12 is connected to the transmission 10, the power output by the electric motor 12 is transmitted to the transmission 10, and the traveling device 4 is driven by the power whose speed is changed by the transmission 10; however, the configuration of the traveling device 4 is not limited to this. For example, a traveling electric motor may be provided separately from the electric motor 12, and the traveling electric motor may be driven by electric power supplied from the battery unit 20. Also, a traveling hydraulic motor may be provided, and a hydraulic pump (not shown) may be driven by power from the electric motor 12, and the traveling hydraulic motor may be driven by hydraulic oil output from the hydraulic pump.

[0026] As shown in FIG. 1, the work vehicle 1 is equipped with a control device 25 and a storage device 26. The control device 25 is a device configured from electric and electronic circuits, programs stored in a CPU, etc., and controls various devices of the work vehicle 1. For example, the control device 25 controls the rotation speed of the electric motor 12 based on the operation of a rotation speed operating device (accelerator pedal) 27, which is an operable operating device provided around the driver's seat 7. The storage device 26 is a non-volatile memory or the like, and stores various information related to the control of the control device 25. For example, the storage device 26 stores information such as a table relating the rotation speed of the electric motor 12 to the amount of operation of the rotation speed operating device 27.

[0027] The work vehicle 1 is equipped with a cooling system 30 that cools the electrical equipment 11. The cooling system 30 has a radiator 31 that cools a refrigerant (cooling water), a cooling pump 40 that sends out the cooling water, and a cooling path (not shown) that circulates the cooling water, and cools the electrical equipment 11 by circulating the cooling water through the electrical equipment 11. 13, the radiator 31 is provided, for example, in the front part of the vehicle body 2. The radiator 31 cools (removes heat from) the coolant passing through it with cooling air generated by a radiator fan 31a. The radiator fan 31a is a suction fan driven by power stepped down by the DC / DC converter 14, and draws in air from the front of the vehicle body 2 and sends the air to the radiator 31.

[0028] 1, the control device 25 has a first control unit 25a. The first control unit 25a is, for example, a vehicle control device that controls at least the inverter 13. In this embodiment, the first control unit 25a is an electronic control unit (ECU (Electronic Control Unit)) that controls the in-vehicle electrical equipment 11 (electrical components). The first control unit 25a is connected to other devices, such as a BMU 20a1 (second control device), a display device 5, a storage device 26, and other ECUs (not shown), via an in-vehicle network N1 such as a CAN (Controller Area Network).

[0029] Now, regarding charging of the battery 20a, the battery 20a has a BMU (battery management unit) 20a1. The BMU 20a1 is a battery monitoring device that monitors and controls the battery unit 20. Therefore, the BMU 20a1 can acquire, for example, the voltage, temperature, current, and terminal voltage of the internal cells of the battery 20a, monitor the battery unit 20, and perform charge control and discharge control of the battery 20a. The BMU 20a1 (second control device) is a device separate from the first control unit 25a. The temperature of the battery 20a is detected, for example, by a temperature detection unit 20c.

[0030] When the voltage of battery 20a reaches a predetermined limit value, BMU 20a1 outputs a charge stop signal to charger 21, and when the voltage of battery 20a is below the limit value, it outputs a charge permission signal to charger 21. When charger 21 receives the charge stop signal from BMU 20a1, it cuts off the charging current to battery 20a by opening and closing a relay in charger 21. On the other hand, when charger 21 receives the charge permission signal from BMU 20a1, it allows the charging current to battery 20a by opening and closing a relay in charger 21.

[0031] When a cable is connected to the charger 21 and power is supplied to the charger 21 from an external source while the BMU 20a1 is outputting a charging permission signal, the BMU 20a1 charges the battery 20a, for example, with a small current for a short time. The BMU 20a1 determines whether the voltage of the battery 20a rises above a predetermined level (pre-charge), and if the voltage of the battery 20a rises above the predetermined level during pre-charge, it outputs a charging start signal to the charger 21, and the charger 21 charges the battery 20a using a method such as CVCC (Constant Current Constant Voltage) charging. The BMU 20a1 determines whether to terminate charging of the battery 20a based on conditions such as the charging time and the amount of electricity being supplied, and if the charging time has elapsed or the amount of electricity being supplied is above a predetermined level, it outputs a charging stop signal to the charger 21, causing the charger 21 to cut off the charging current and terminate charging of the battery 20a.

[0032] On the other hand, if the voltage of the battery 20a does not rise above a predetermined level during pre-charging, the BMU 20a1 outputs a charge stop signal to the charger 21, causing the charger 21 to cut off the charging current and terminate charging of the battery 20a. The control device 25 has a charging determination unit 25b. The charging determination unit 25b is composed of electric and electronic circuits provided in the control device 25, programs stored in the CPU, storage device 26, etc. The charging determination unit 25b acquires information about the battery 20a from outside the control device 25 and determines whether the battery 20a is being charged. In this embodiment, the charging determination unit 25b acquires signals (a charging stop signal and a charging start signal) from the BMU 20a1 to determine whether the battery 20a is being charged. Note that the means for determining whether the charging determination unit 25b is being charged is not limited to the means described above, as long as it can determine whether the battery 20a is being charged.

[0033] 2 is a diagram showing an example of a circuit configuration in which two control units control switching of a switching unit. As shown in FIG. 2, the battery unit 20 includes a switching unit SW. The switching unit SW is arranged on a power supply line VL1 that connects the battery 20a and the electric device 11. The switching unit SW switches between a connected state (i.e., an ON state) in which the battery unit 20 is electrically connected to the electric device 11 (such as the inverter 13 and the DC / DC converter 14), and a disconnected state (i.e., an OFF state) in which the battery unit 20 is not electrically connected to the electric device 11 (such as the inverter 13 and the DC / DC converter 14). In this embodiment, the switching unit SW is an electric component such as a relay or a semiconductor switch, but various electric components that switch between a connected state and a disconnected state based on a control signal may also be used.

[0034] The first control unit 25a outputs a connection signal or a non-connection signal to the switching unit SW. The BMU 20a1 (second control unit) outputs a connection signal or a non-connection signal to the switching unit SW. The switching unit SW is in a connected state when a connection signal is input from each of the first control unit 25a and the BMU 20a1 (second control unit). That is, the switching unit SW is in a connected state when a connection signal is input from both the first control unit 25a and the BMU 20a1 (second control unit). When the switching unit SW is in a connected state, power from the battery unit 20 is supplied to the electric devices 11 (such as the inverter 13 and the DC / DC converter 14). On the other hand, when a non-connection signal is input from at least one of the first control unit 25a and the BMU 20a1 (second control unit), the switching unit SW is in a non-connected state. When the switching unit SW is in a non-connected state, power from the battery unit 20 is not supplied to the electric devices 11 (such as the inverter 13 and the DC / DC converter 14).

[0035] FIG. 3 is a diagram showing an example of the circuit configuration of the switching unit SW. More specifically, as shown in FIG. 3, the switching unit SW has a first switching unit SW1, a second switching unit SW2, and a third switching unit SW3. The first switching unit SW1 and the second switching unit SW2 are connected in series to SL1 on a signal line connected to a +12V power supply. The first switching unit SW1 and the second switching unit SW2 are, for example, relays, semiconductor switches, switching elements, etc. The first control unit 25a outputs a connection signal or a non-connection signal to the first switching unit SW1. The first switching unit SW1 switches between a connection state and a non-connection state based on the control signal (connection signal or non-connection signal) from the first control unit 25a.

[0036] Specifically, the first switching unit SW1 enters a connected state when a connection signal is input, and enters a disconnected state when a disconnection signal is input. The BMU 20a1 (second control unit) outputs a connection signal or a disconnection signal to the second switching unit SW2. The second switching unit SW2 switches between a connected state and a disconnected state based on a control signal (connection signal or disconnection signal) from the BMU 20a1 (second control unit). Specifically, the second switching unit SW2 enters a connected state when a connection signal is input, and enters a disconnected state when a disconnection signal is input.

[0037] The third switching unit SW3 is disposed on the power supply line VL1 and switches between a connected state and a disconnected state. The third switching unit SW3 is a relay (contact relay) having a coil C1 connected to the signal line SL1 and a contact C2 connected to the power supply line VL1 and switched between a connected state and a disconnected state by the coil C1. When the first switching unit SW1 and the second switching unit SW2 are in the connected state, a current flows through the coil C1, turning the contact C2 ON, and the third switching unit SW3 switches to the connected state. When the third switching unit SW3 switches to the connected state in this manner, power is supplied from the battery unit 20 to the electric device 11.

[0038] On the other hand, the third switching unit SW3 is in a disconnected state when at least one of the first switching unit SW1 and the second switching unit SW2 is in a disconnected state, and no current flows through the coil unit C1, so the contact unit C2 is in an OFF state, thereby entering a disconnected state. When the third switching unit SW3 is in a disconnected state in this manner, power is not supplied from the battery unit 20 to the electrical device 11. Note that the third switching unit SW3 is not limited to a contact relay, and may be a contactless relay (solid-state relay: SSR) or the like.

[0039] When a normal signal is input from another device connected via the in-vehicle network N1, the first control unit 25a determines that the battery unit 20 is normal, and outputs a connection signal to the first switching unit SW1 and an operation command signal to the BMU 20a1 (second control unit). When the BMU 20a1 (second control unit) receives the operation command signal from the first control unit 25a and determines that the battery unit 20 is normal, it outputs a connection signal to the second switching unit SW2.

[0040] When the BMU 20a1 (second control unit) determines that the battery unit 20 is abnormal, it outputs a non-connection signal to the second switching unit SW2 and outputs an abnormality signal to the first control unit 25a. When the abnormality signal is input from the BMU 20a1 (second control unit), the first control unit 25a outputs a non-connection signal to the first switching unit SW1. Here, battery control by the two control units, i.e., the first control unit 25a and the BMU 20a1 (second control unit), will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a flowchart showing the battery output start process of the first embodiment. Fig. 5 is a flowchart showing the battery output stop process in the event of an abnormality of the first embodiment.

[0041] First, the flow of starting battery output by the first control unit 25a and BMU 20a1 (second control unit) in the first embodiment will be described with reference to Fig. 4. When an operator (driver) turns on, for example, an ignition key (not shown), the first control unit 25a (ECU) is started by power supply from the vehicle battery 15 (S1). The power supply from the vehicle battery 15 also starts the BMU 20a1 (second control unit), the display device 5, the storage device 26, and other ECUs (not shown).

[0042] The first control unit 25a (ECU) receives status signals (normal signals, error signals) from other devices connected to the in-vehicle network N1 (i.e., the BMU 20a1 (second control unit), the display device 5, the storage device 26, other ECUs not shown, etc.). The first control unit 25a determines whether or not there is an error signal from the other devices connected to the in-vehicle network N1 (S2).

[0043] If no error signal is received from another device connected to the in-vehicle network N1 (S2, No), the first control unit 25a outputs a connection signal to the first switching unit SW1 to turn on the first switching unit SW1 (S3). That is, the first control unit 25a (ECU) sets the first switching unit SW1 to the connection state. The first control unit 25a (ECU) outputs an operation command signal to the BMU 20a1 (second control unit) (S4).

[0044] When the BMU 20a1 (second control unit) receives an operation command signal from the first control unit 25a and determines that the battery unit 20 is normal, it outputs a connection signal to the second switching unit SW2 to turn on the second switching unit SW2 (S5). That is, the BMU 20a1 (second control unit) switches the second switching unit SW2 to the connected state. When the first switching unit SW1 and the second switching unit SW2 are in the connected state, the third switching unit SW3 shown in FIG. 3 switches to the connected state when a current flows through the coil unit C1, turning the contact unit C2 on. That is, when the third switching unit SW3 switches to the connected state, power is supplied from the battery unit 20 to the electric device 11.

[0045] On the other hand, if an error signal is input from another device connected to the in-vehicle network N1 (S2, Yes), the first control unit 25a terminates this process. That is, the process of turning on the first switching unit SW1 (S3) and the process of turning on the second switching unit SW2 (S5) are not performed. Therefore, when at least one of the first switching unit SW1 and the second switching unit SW2 is in a disconnected state, the third switching unit SW3 shown in FIG. 3 is in a disconnected state. Since no current flows through the coil C1, the contact C2 is in an OFF state. In other words, the third switching unit SW3 is in a disconnected state. Because the third switching unit SW3 is in a disconnected state, power from the battery unit 20 is not supplied to the electrical device 11.

[0046] Next, a flow of stopping battery output by the first control unit 25a and the BMU 20a1 (second control unit) in the first embodiment when an abnormality occurs will be described with reference to FIG. 5, the BMU 20a1 (second control unit) constantly monitors the battery unit 20 and detects whether or not there is an abnormality in the battery unit 20 (S11). If the BMU 20a1 detects an abnormality in the battery unit 20 (S11, Yes), it outputs a disconnection signal to the second switching unit SW2 and turns off the second switching unit SW2 (S12). In other words, the BMU 20a1 (second control unit) sets the second switching unit SW2 to the disconnection state.

[0047] Next, the BMU 20a1 (second control unit) outputs an abnormality signal to the first control unit 25a (ECU) (S13). When the abnormality signal is input from the BMU 20a1 (second control unit), the first control unit 25a (ECU) outputs a disconnection signal to the first switching unit SW1 to turn off the first switching unit SW1 (S14). In other words, the first control unit 25a (ECU) puts the first switching unit SW1 into a disconnection state. After S14, this process ends.

[0048] On the other hand, if the BMU 20a1 (second control unit) has not detected an abnormality in the battery unit 20 (S11, No), the process returns to S11 and the BMU 20a1 (second control unit) continues to detect whether or not an abnormality in the battery unit 20 exists.

[0049] The work vehicle 1 of the first embodiment described above comprises an electrical device 11, a battery unit 20 having a battery 20a that supplies power to the electrical device 11, a switching unit SW arranged on a power supply line VL1 that connects the battery 20a and the electrical device 11 and that switches between a connection state in which the battery unit 20 and the electrical device 11 are electrically connected and a disconnection state in which the battery unit 20 and the electrical device 11 are not electrically connected, a first control unit 25a that outputs a connection signal or a disconnection signal to the switching unit SW, and a BMU 20a1 (second control unit) that outputs a connection signal or a disconnection signal to the switching unit SW. When a connection signal is input from the first control unit 25a and the BMU 20a1 (second control unit), the switching unit SW enters a connection state, and power from the battery unit 20 is supplied to the electrical device 11, and when a disconnection signal is input from at least one of the first control unit 25a and the BMU 20a1 (second control unit), the switching unit SW enters a disconnection state, and power from the battery unit 20 is not supplied to the electrical device 11.

[0050] According to this configuration, the first control unit 25a and the BMU 20a1 (second control unit) are connected to the switching unit SW When the first control unit 25a and the BMU 20a1 (second control unit) are switched to the connected state, the power output from the battery unit 20 can be reliably controlled. Furthermore, even if one of the first control unit 25a and the BMU 20a1 (second control unit) fails, the other (i.e., the one that is not failed) can switch the switching unit SW to the non-connected state, thereby reliably stopping the power output from the battery unit 20. This ensures redundancy in battery control.

[0051] For example, to explain in detail the stopping of power output from the battery unit 20, in a configuration in which a single control unit switches the switching unit SW, there is a risk that the switching unit SW cannot be switched to the disconnected state due to a failure of the control unit, damage to the harness connecting the control unit and the switching unit SW, a bug in the software executed by the control unit, or the like, and therefore it is not possible to stop the power from the battery unit 20. In contrast, in a configuration in which at least one of the first control unit 25a and the BMU 20a1 (second control unit) switches the switching unit SW to the disconnected state, the probability that the first control unit 25a, the BMU 20a1 (second control unit), etc. will simultaneously fail is low, so that the one of the first control unit 25a and the BMU 20a1 (second control unit) that is not failing can switch the switching unit SW to the disconnected state, and the power from the battery unit 20 can be properly stopped.

[0052] The switching unit SW also has a first switching unit SW1 and a second switching unit SW2 that are connected in series to the signal line SL1 and switch between a connected state and a disconnected state, and a third switching unit SW3 that is arranged on the power supply line VL1 and switches between a connected state and a disconnected state, the first control unit 25a outputs a connect signal or a disconnected signal to the first switching unit SW1, the BMU 20a1 (second control unit) outputs a connect signal or a disconnected signal to the second switching unit SW2, the third switching unit SW3 is in a connected state when the first switching unit SW1 and the second switching unit SW2 are in a connected state and supplies power from the battery unit 20 to the electrical device 11, and is in a disconnected state when at least one of the first switching unit SW1 and the second switching unit SW2 is in a disconnected state and does not supply power from the battery unit 20 to the electrical device 11.

[0053] According to this configuration, by switching to a disconnected state one of the first switching unit SW1 and the second switching unit SW2 connected in series on the signal line SL1, the third switching unit SW3 on the power supply line VL1 is switched to a disconnected state, thereby stopping the power output of the battery unit 20. This ensures redundancy in battery control and allows the circuit to be separated between the signal line SL1 and the power supply line VL1.

[0054] The third switching unit SW3 is a relay having a coil C1 connected to the signal line SL1 and a contact C2 connected to the power supply line VL1 and switched between a connected state and a disconnected state by the coil C1. With this configuration, by switching one of the first switching unit SW1 and the second switching unit SW2 connected in series to the signal line SL1 to a disconnected state, current stops flowing through the coil C1 on the signal line SL1 of the relay, and the contact C2 on the power supply line VL1 of the relay switches to a disconnected state, thereby stopping the power output of the battery unit 20. This ensures redundancy in battery control, and the relay having the coil C1 and the contact C2 can separate the circuit between the signal line SL1 and the power supply line VL1.

[0055] Furthermore, when a normal signal is input from another device connected via the in-vehicle network N1, the first control unit 25a determines that the battery unit 20 is normal, and outputs a connection signal to the first switching unit SW1 and outputs an operation command signal to the BMU 20a1 (second control unit), and when the BMU 20a1 (second control unit) receives the operation command signal from the first control unit 25a and determines that the battery unit 20 is normal, it outputs a connection signal to the second switching unit SW2. According to this configuration, when the first control unit 25a determines that another device connected via the in-vehicle network is normal, it sets the first switching unit SW1 to the connection state and outputs an operation command signal to the BMU 20a1 (second control unit), and when the BMU 20a1 (second control unit) receives the operation command signal from the first control unit 25a and determines that the battery unit 20 is normal, it sets the second switching unit SW2 to the connection state. Therefore, when it is determined that the first control unit 25a and the BMU 20a1 (second control unit) are normal, power output is executed from the battery unit 20. This ensures redundancy in the control of the start of battery output, and ensures reliable control of the start of output from the battery unit 20.

[0056] Furthermore, when the BMU 20a1 (second control unit) determines that the battery unit 20 is abnormal, it outputs a disconnection signal to the second switching unit SW2 and outputs an abnormality signal to the first control unit 25a, and when the abnormality signal is input from the BMU 20a1 (second control unit), the first control unit 25a outputs a disconnection signal to the first switching unit SW1. According to this configuration, when the battery unit 20 is abnormal, the BMU 20a1 (second control unit) sets the second switching unit SW2 to the disconnection state, and the first control unit 25a sets the first switching unit SW1 to the disconnection state, so that the first control unit 25a and the BMU 20a1 (second control unit) can stop the power output of the battery unit 20. This ensures redundancy in the control of stopping the battery output, and ensures reliable control when stopping the output of the battery unit 20.

[0057] The vehicle also includes a vehicle body 2 having a traveling device 4, and the electric equipment 11 includes an inverter 13 supplied with power from a battery unit 20 and an electric motor 12 that drives the traveling device 4 based on AC power converted by the inverter 13. The first control unit 25a is a vehicle control unit (ECU) that controls at least the inverter 13, and the BMU 20a1 (second control unit) is a battery monitoring device that monitors and controls the battery unit 20. With this configuration, the vehicle control unit (ECU) or the battery monitoring device that is not malfunctioning can switch the switching unit SW to a non-connected state, thereby stopping the power output of the battery unit 20. As a result, by utilizing the vehicle control unit (ECU) and the battery monitoring device, redundancy in battery control can be ensured, and the battery unit 20 can be reliably controlled.

[0058] [Second embodiment] Fig. 6 is a diagram showing an example of the circuit configuration of the second embodiment. Fig. 7 is a diagram showing an example of the circuit configuration of the switching unit SW of the second embodiment. The circuit configuration of the second embodiment differs from the circuit configuration of the first embodiment in that the second switching unit SW2 has a switching unit SW21 for charging the battery and a switching unit SW22 for discharging the battery. Note that the same components as those of the first embodiment are given the same reference numerals, and their description will be omitted.

[0059] As shown in FIGS. 6 and 7, the second switching unit SW2 has a switching unit SW21 for charging the battery 20a and a switching unit SW22 for discharging the battery 20a. When a normal signal is input from another device connected via the in-vehicle network N1, the first control unit 25a determines that the device is normal. If the first control unit 25a determines that the device is normal, it outputs a connection signal to the first switching unit SW1 and outputs an operation command signal to the BMU 20a1 (second control unit), regardless of whether the battery 20a is being charged or discharged.

[0060] When the BMU20a1 (second control unit) receives an operation command signal from the first control unit 25a and determines that the battery unit 20 is normal, it outputs a connection signal to the charging switching unit SW21 and a non-connection signal to the discharging switching unit SW22 if the battery 20a is being charged, and outputs a non-connection signal to the charging switching unit SW21 and a connection signal to the discharging switching unit SW22 if the battery 20a is being discharged.

[0061] 6, a switch SW21A is provided in the power supply line connecting the battery unit 20 and the charger 21, and the switch SW21A is switched to a connected state in conjunction with the charging switching unit SW21 being switched to a connected state. The switch SW21A is switched to a disconnected state in conjunction with the charging switching unit SW21 being switched to a disconnected state. In addition, a switch SW22A is provided in the power supply line connecting the battery unit 20 and the electrical device 11, and the switch SW22A is switched to a connected state in conjunction with the discharging switching unit SW22 being switched to a connected state. The switch SW22A is switched to a disconnected state in conjunction with the discharging switching unit SW22 being switched to a disconnected state.

[0062] When the BMU 20a1 (second control unit) determines that the battery unit 20 is abnormal, it outputs a disconnection signal to the charge switching unit SW21 and the discharge switching unit SW22, and also outputs an abnormality signal to the first control unit 25a. When the abnormality signal is input from the BMU 20a1 (second control unit), the first control unit 25a outputs a disconnection signal to the first switching unit SW1. Here, the flow of starting battery output by the first control unit 25a and the BMU 20a1 (second control unit) in the second embodiment will be described with reference to Fig. 8A. Since S1 to S4 in Fig. 8A are the same as those in the first embodiment, S4A to S4C in Fig. 8A that are different from those in the first embodiment will be described.

[0063] When the BMU 20a1 (second control unit) receives an operation command signal from the first control unit 25a and determines that the battery unit 20 is normal, it determines whether the battery 20a is being charged or discharged (S4A). For example, the BMU 20a1 (second control unit) determines that the battery 20a is being charged when it is being charged by the charger 21, and determines that the battery 20a is not being charged when it is not being charged by the charger 21. The BMU 20a1 (second control unit) may also determine whether the battery 20a is being charged based on the voltage, current, terminal voltage of the internal cells, etc. of the battery 20a.

[0064] If the battery 20a is being charged (S4A, Yes), the BMU 20a1 (second control unit) outputs a connection signal to the charging switching unit SW21 of the second switching unit SW2 (S4C) and a non-connection signal to the discharging switching unit SW22 of the second switching unit SW2. Thus, the first switching unit SW1 is in the connected state, the charging switching unit SW21 of the second switching unit SW2 is in the connected state, and the discharging switching unit SW22 of the second switching unit SW2 is in the non-connected state. The third switching unit SW3 shown in FIG. 7 is in the connected state when a current flows through the coil C1, turning on the contact C2. That is, when the third switching unit SW3 is in the connected state, power is supplied from the charger 21 to the battery unit 20. This causes the battery 20a to be charged.

[0065] Meanwhile, in S4A, if the battery 20a is discharging (S4A, No), the BMU 20a1 (second control unit) outputs a disconnection signal to the charging switching unit SW21 and a connection signal to the discharging switching unit SW22 (S4B). Thus, the first switching unit SW1 is in the connected state, the discharging switching unit SW22 of the second switching unit SW2 is in the connected state, and the charging switching unit SW21 of the second switching unit SW2 is in the disconnected state. The third switching unit SW3 shown in FIG. 7 is in the connected state when a current flows through the coil C1, turning the contact C2 on. That is, when the third switching unit SW3 is in the connected state, power is supplied from the battery unit 20 to the electrical device 11. This causes the battery 20a to discharge. After the processing of S4B or S4C, this processing ends.

[0066] Next, the flow of stopping battery output when an abnormality occurs by the first control unit 25a and the BMU 20a1 (second control unit) of the second embodiment will be described with reference to Fig. 8B. Fig. 8B is a flowchart showing the battery output stopping process when an abnormality occurs in the second embodiment. Since S11, S13, and S14 in FIG. 8B are the same as those in the first embodiment, only S12A in FIG. 8B, which differs from the first embodiment, will be described.

[0067] 8B, when the BMU 20a1 (second control unit) detects an abnormality in the battery unit 20 (S11, Yes), it outputs a disconnection signal to the second switching unit SW2 and turns off both the charging switching unit SW21 and the discharging switching unit SW22 of the second switching unit SW2 (S12A). That is, the BMU 20a1 (second control unit) puts both the charging switching unit SW21 and the discharging switching unit SW22 of the second switching unit SW2 into a disconnected state. As a result, if the battery 20a is being charged, the supply of power from the charger 21 to the battery unit 20 is stopped due to the abnormality detection. Also, if the battery 20a is being discharged, the supply of power from the battery unit 20 to the electrical device 11 is stopped due to the abnormality detection.

[0068] In the work vehicle 1 of the second embodiment described above, the second switching unit SW2 has a switching unit SW21 for charging the battery 20a and a switching unit SW22 for discharging the battery 20a, and when the first control unit 25a determines that the battery is normal, it outputs a connection signal to the first switching unit SW1 and outputs an operation command signal to the BMU 20a1 (second control unit), regardless of whether the battery 20a is being charged or discharged. When the operation command signal from the first control unit 25a is input and the BMU 20a1 (second control unit) determines that the battery unit 20 is normal, if the battery 20a is being charged, it outputs a connection signal to the charging switching unit SW21 and a disconnection signal to the discharging switching unit SW22, and if the battery 20a is being discharged, it outputs a disconnection signal to the charging switching unit SW21 and a connection signal to the discharging switching unit SW22.

[0069] According to this configuration, when the first control unit 25a and the BMU 20a1 (second control unit) are determined to be normal, if the battery 20a is being charged, the charging switch SW21 is set to the connected state and the discharging switch SW22 is set to the disconnected state, and charging to the battery unit 20 is performed. If the battery 20a is being discharged, the charging switch SW21 is set to the disconnected state and the discharging switch SW22 is set to the connected state, thereby discharging (i.e., power output) the battery unit 20. This ensures redundancy in the control of the start of charging and discharging of the battery 20a, and ensures reliable control at the start of charging and discharging of the battery unit 20.

[0070] Furthermore, when the BMU 20a1 (second control unit) determines that the battery unit 20 is abnormal, it outputs a disconnection signal to the charge switching unit SW21 and the discharge switching unit SW22 and outputs an abnormality signal to the first control unit 25a. When the abnormality signal is input from the BMU 20a1 (second control unit), the first control unit 25a outputs a disconnection signal to the first switching unit SW1. With this configuration, when the battery unit 20 is abnormal, the BMU 20a1 (second control unit) puts the charge switching unit SW21 and the discharge switching unit SW22 into a disconnection state, and the first control unit 25a puts the first switching unit SW1 into a disconnection state. This allows the first control unit 25a and the BMU 20a1 (second control unit) to stop charging and discharging of the battery unit 20. This ensures redundancy in the control of stopping charging and discharging of the battery 20a, and ensures reliable control when stopping charging and discharging of the battery unit 20.

[0071] [Third embodiment] 9 is a diagram showing an example of the circuit configuration of the switching unit SW of the third embodiment. The circuit configuration of the third embodiment differs from the circuit configuration of the first embodiment in that a spare switching unit SW11 is provided in parallel with the first switching unit SW1. Note that the same components as those of the first embodiment are given the same reference numerals, and their description will be omitted.

[0072] The switching unit SW includes a spare switching unit SW11 that is connected in parallel to the first switching unit SW1 and that switches between a connected state and a non-connected state. If the first switching unit SW1 does not switch to the connected state and no abnormality signal is input from the BMU 20a1 (second control unit), the first control unit 25a outputs a connection signal to the standby switching unit SW11, and if the first switching unit SW1 is in the connected state, the first control unit 25a does not output a connection signal to the standby switching unit SW11.

[0073] If the first switching unit SW1 does not switch to the connected state, the first control unit 25a causes the display device 5 to display a message M1 prompting the instruction to switch the backup switching unit SW11 to the connected state, and when an instruction to switch based on an operation on the display device 5 or another operating device is received, the first control unit 25a outputs a connection signal to the backup switching unit SW11. Here, the flow of starting battery output by the first control unit 25a and BMU 20a1 (second control unit) in the third embodiment will be described with reference to Fig. 10. Fig. 10 is a flowchart showing the battery output start process in the third embodiment. Since S1 to S5 in Fig. 10 are the same as in the first embodiment, S31 to S34 in Fig. 10 that are different from the first embodiment will be described.

[0074] The first control unit 25a outputs a connection signal to the first switching unit SW1 to turn on the first switching unit SW1 (S3). After S3, the first control unit 25a determines whether the first switching unit SW1 is on (S31). For example, the first control unit 25a determines that the first switching unit SW1 is on if a voltage signal from a voltage sensor (not shown) that detects the voltage between the first switching unit SW1 and the third switching unit SW3 is equal to or greater than a specified voltage value, and determines that the first switching unit SW1 is off if the voltage signal is less than the specified voltage value. The first control unit 25a may also determine that the first switching unit SW1 is on if a current value from a current sensor (not shown) provided between the first switching unit SW1 and the third switching unit SW3 is equal to or greater than a specified current value, and determine that the first switching unit SW1 is off if the current value is less than the specified current value. Furthermore, the first control unit 25a may determine whether the first switching unit SW1 is on or not based on a state signal (a signal indicating a connected state or a non-connected state) from the first switching unit SW1.

[0075] If the first control unit 25a determines that the first switching unit SW1 is on (S31, Yes), the process proceeds to S4. On the other hand, if the first control unit 25a determines that an abnormality signal has not been input from the BMU 20a1 (second control unit) and that the first switching unit SW1 is off (S31, No), the first control unit 25a reads out a message M1 from the storage device 26, prompting an instruction to switch the standby switching unit SW11 to the connected state, and displays the message M1 on the display device 5. The storage device 26 stores this message M1 in advance.

[0076] Fig. 11 is a diagram showing an example of a message screen in the third embodiment. As shown in Fig. 11, the display device 5 displays a message screen including a message M1 such as "The first switching unit has failed. Would you like to use the backup switching unit?" under display control from the first control unit 25a. The first control unit 25a determines whether or not a switching instruction has been issued (S33). For example, the message screen shown in Fig. 11 displays a selection button 5a for accepting a switching instruction and a selection button 5b for accepting no switching instruction. The display device 5 has a touch panel function and can accept touch instructions on the screen.

[0077] When the operator selects the selection button 5a (S33, Yes), the first control unit 25a outputs a connection signal to the backup switching unit SW11 to turn on the backup switching unit SW11. That is, the backup switching unit SW11 is set to the connected state. Here, the first control unit 25a receives a switching instruction based on a touch operation on the display device 5, but this is not limiting. For example, the first control unit 25a may receive a switching instruction based on an operation on another operating device (such as an operating lever or an operating switch) arranged around the driver's seat 7.

[0078] On the other hand, the first control unit 25a terminates this process if the operator selects the selection button 5b (S33, No), after S34, after S5, or if no error signal is input (S2, No).

[0079] The work vehicle 1 of the third embodiment described above is equipped with a backup switching unit SW11 that is connected in parallel to the first switching unit SW1 and that switches between a connected state and a disconnected state, and the first control unit 25a outputs a connect signal to the backup switching unit SW11 when the first switching unit SW1 does not switch to the connected state and no abnormality signal is input from the BMU 20a1 (second control unit), and does not output a connect signal to the backup switching unit SW11 when the first switching unit SW1 is in the connected state. With this configuration, even if the first switching unit SW1 fails, as long as there is no abnormality in the battery unit 20 (that is, the battery unit 20 is in a usable state), power can be output by the battery unit 20 by switching the backup switching unit SW11 to the connected state.

[0080] The battery unit 20 further includes a display device 5. When the first switching unit SW1 does not switch to the connected state, the first control unit 25a causes the display device 5 to display a message M1 prompting an instruction to switch the backup switching unit SW11 to the connected state. When the first control unit 25a receives a switching instruction based on an operation on the display device 5 or another operating device, the first control unit 25a outputs a connection signal to the backup switching unit SW11. With this configuration, if the first switching unit SW1 fails but there is no abnormality in the battery unit 20 (i.e., the battery unit 20 is usable), the message M1 displayed on the display device 5 (i.e., a message prompting an instruction to switch the backup switching unit SW11 to the connected state) can be notified to relevant parties (e.g., workers, drivers, owners, managers, etc.). Based on this notification, relevant parties can determine whether or not the battery unit 20 is to be used in an emergency. When the battery unit 20 is to be used in an emergency, the relevant parties operate the display device 5 or another operating device to instruct the first control unit 25a to switch, thereby setting the backup switching unit SW11 to the connected state, thereby enabling the battery unit 20 to be used in an emergency.

[0081] In the third embodiment, the first control unit 25a may start timing using a timing device (e.g., a real-time clock) possessed by the first control unit 25a when it receives a switching instruction based on an operation on the display device 5 or another operating device, and when the time measured by the timing device (i.e., the preliminary usage time) reaches a predetermined specified time (e.g., 2 hours), it may display at least one of a message indicating that the preliminary usage time has reached the predetermined specified time and a message urging the user to replace the first switching unit SW1 on the display device 5.

[0082] [Fourth embodiment] FIG. 12 is a diagram showing an example of a circuit configuration of the fourth embodiment. The circuit configuration differs from that of the first embodiment in that the switching unit SW includes a first switching unit SW101 and a second switching unit 102 connected in series to the power supply line VL1. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted.

[0083] The switching unit SW has a first switching unit SW101 and a second switching unit SW102 that are connected in series to the power supply line VL1 and are switched between a connected state and a non-connected state. The first control unit 25a outputs a connection signal or a non-connection signal to the first switching unit SW101. The BMU 20a1 (second control unit) outputs a connection signal or a non-connection signal to the second switching unit SW102.

[0084] When the first switching unit SW101 and the second switching unit 102 are in a connected state, power from the battery unit 20 is supplied to the electrical device 11, and when at least one of the first switching unit SW101 and the second switching unit 102 is in a disconnected state, power from the battery unit 20 is not supplied to the electrical device 11. According to this configuration, it is rare for the first switching unit 101 and the second switching unit 102 to fail at the same time, and the non-failed one of the first switching unit SW101 and the second switching unit 102 can be switched to the non-connected state, making it possible to more reliably stop the power output of the battery unit 20. In other words, because the switching unit SW has the first switching unit SW101 and the second switching unit 102, redundancy can also be ensured for the switching unit SW, making it possible to more reliably control the battery unit 20.

[0085] Furthermore, in each of the above embodiments, the switching of the switching unit SW is controlled by two control units (i.e., the first control unit 25a and the BMU 20a1 (second control unit)), but the switching may be controlled by three or more control units. Furthermore, in each of the above embodiments, the first switching unit SW1 is provided inside the battery unit 20, but it may also be provided outside the battery unit 20.

[0086] Furthermore, in each of the above embodiments, an example has been described in which the work vehicle 1 is a tractor, but the work vehicle 1 is not limited to a tractor and may be any vehicle that is driven by electricity stored in the battery 20a. For example, the work vehicle 1 may be an agricultural machine such as a combine harvester, rice transplanter, or lawnmower, or may be a construction machine such as a backhoe, wheel loader, compact track loader, or skid steer loader, or may be an industrial machine such as a forklift.

[0087] Although the present invention has been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0088] 1 Work vehicle 2. Body 4 Running gear 11 Electrical Equipment 12 Electric motor 13 Inverter 20 Battery Unit 20a battery 25a First control section 20a1 BMU (2nd control unit) C1 Coil section C2 contact part N1 In-Vehicle Network SL1 signal line SW switching section SW1 1st switching section SW11 spare switching unit SW2 2nd switching section SW21 Charging switching section SW22 Discharge switching section SW3 3rd switching section VL1 power line

Claims

1. Electrical equipment and a battery unit having a battery for supplying power to the electrical device; a switching unit that is disposed on a power supply line that connects the battery and the electrical device, and that switches between a connected state in which the battery unit and the electrical device are electrically connected and a disconnected state in which the battery unit and the electrical device are not electrically connected; a first control unit that outputs a connection signal or a non-connection signal to the switching unit; a second control unit that outputs a connection signal or a non-connection signal to the switching unit, the switching unit is set to the connected state when a connection signal is input from the first control unit and the second control unit, respectively, and power from the battery unit is supplied to the electrical device; and is set to the disconnected state when a disconnection signal is input from at least one of the first control unit and the second control unit, and power from the battery unit is not supplied to the electrical device; the switching unit includes a first switching unit and a second switching unit that are connected in series and switch between a connected state and a non-connected state; the first control unit outputs a connection signal or a non-connection signal to the first switching unit; the second control unit outputs a connection signal or a non-connection signal to the second switching unit, When the first switching unit and the second switching unit are in the connected state, power is supplied from the battery unit to the electrical device, and when at least one of the first switching unit and the second switching unit is in the disconnected state, power is not supplied from the battery unit to the electrical device; the first control unit determines that the device is normal when a normal signal is input from another device connected via the in-vehicle network, and outputs a connection signal to the first switching unit and an operation command signal to the second control unit; the second control unit outputs a connection signal to the second switching unit when the operation command signal from the first control unit is input and the second control unit determines that the battery unit is normal; the second switching unit has a switching unit for charging the battery and a switching unit for discharging the battery, When the first control unit determines that the battery is normal, it outputs a connection signal to the first switching unit and outputs the operation command signal to the second control unit regardless of whether the battery is being charged or discharged, When the second control unit receives the operation command signal from the first control unit and determines that the battery unit is normal, it outputs a connection signal to the charging switching unit and a non-connection signal to the discharging switching unit if the battery is being charged, and outputs a non-connection signal to the charging switching unit and a connection signal to the discharging switching unit if the battery is being discharged.

2. the switching unit includes a first switching unit and a second switching unit connected in series to the signal line and switching between a connected state and a non-connected state, and a third switching unit disposed on the power supply line and switching between a connected state and a non-connected state; the first control unit outputs a connection signal or a non-connection signal to the first switching unit; the second control unit outputs a connection signal or a non-connection signal to the second switching unit, 2. The work vehicle according to claim 1, wherein the third switching unit is in the connected state when the first switching unit and the second switching unit are in the connected state, and supplies power from the battery unit to the electrical equipment, and is in the disconnected state when at least one of the first switching unit and the second switching unit is in the disconnected state, and does not supply power from the battery unit to the electrical equipment.

3. 3. The work vehicle according to claim 2, wherein the third switching unit is a relay having a coil portion connected to the signal line and a contact portion connected to the power supply line and switched between a connected state and a non-connected state by the coil portion.

4. When the second control unit determines that the battery unit is abnormal, the second control unit outputs a disconnection signal to the charging switching unit and the discharging switching unit, and outputs an abnormality signal to the first control unit; The work vehicle according to claim 1 , wherein the first control unit outputs a disconnection signal to the first switching unit when the abnormality signal is input from the second control unit.

5. a vehicle body having a running device; the electrical equipment includes an inverter to which power from the battery unit is supplied, and an electric motor that drives the traveling device based on the AC power converted by the inverter, the first control unit is a vehicle control device that controls at least the inverter, The work vehicle according to claim 1 , wherein the second control unit is a battery monitoring device that monitors and controls the battery unit.

6. An electrical device; a battery unit having a battery for supplying power to the electrical device; a switching unit that is disposed on a power supply line that connects the battery and the electrical device, and that switches between a connected state in which the battery unit and the electrical device are electrically connected and a disconnected state in which the battery unit and the electrical device are not electrically connected; a first control unit that outputs a connection signal or a non-connection signal to the switching unit; a second control unit that outputs a connection signal or a non-connection signal to the switching unit, the switching unit is set to the connected state when a connection signal is input from the first control unit and the second control unit, respectively, and power from the battery unit is supplied to the electrical device; and is set to the disconnected state when a disconnection signal is input from at least one of the first control unit and the second control unit, and power from the battery unit is not supplied to the electrical device; the switching unit includes a first switching unit and a second switching unit that are connected in series and switch between a connected state and a non-connected state; the first control unit outputs a connection signal or a non-connection signal to the first switching unit; the second control unit outputs a connection signal or a non-connection signal to the second switching unit, When the first switching unit and the second switching unit are in the connected state, power is supplied from the battery unit to the electrical device, and when at least one of the first switching unit and the second switching unit is in the disconnected state, power is not supplied from the battery unit to the electrical device; the first control unit determines that the device is normal when a normal signal is input from another device connected via the in-vehicle network, and outputs a connection signal to the first switching unit and an operation command signal to the second control unit; the second control unit outputs a connection signal to the second switching unit when the operation command signal from the first control unit is input and the second control unit determines that the battery unit is normal; When the second control unit determines that the battery unit is abnormal, the second control unit outputs a disconnection signal to the second switching unit and an abnormality signal to the first control unit; the first control unit outputs a disconnection signal to the first switching unit when the abnormality signal is input from the second control unit; a backup switching unit connected in parallel to the first switching unit and switching between a connected state and a non-connected state; The first control unit outputs a connection signal to the standby switching unit when the first switching unit does not switch to the connected state and no abnormality signal is input from the second control unit, and does not output a connection signal to the standby switching unit when the first switching unit is in the connected state.

7. A display device is provided, 7. The work vehicle according to claim 6, wherein the first control unit, when the first switching unit does not switch to the connected state, causes the display device to display a message prompting an instruction to switch the backup switching unit to the connected state, and when the first control unit receives the instruction to switch based on an operation on the display device or another operating device, outputs a connection signal to the backup switching unit.

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