Work machine and method for charging battery

Abstract

A work machine is provided with: a rotating body; a working machine connected to the rotating body; and a power supply device that can be connected to an external power source and supplies power to a power supply target.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a work machine and a method of charging a battery. BACKGROUND

[0002] Patent Literature 1 discloses a technology of wireless energy transfer between vehicles.

[0003] Patent Literature 1: U.S. Patent Application Publication No. 2021 / 0323420 Specification SUMMARY

[0004] A work machine works at a work site. An electric work machine has a battery. The battery is charged by power supply from a charging station. There is a demand for a technology capable of supplying power to a power supply target by a method different from a method of utilizing a charging station.

[0005] An object of the present disclosure is to supply power to a power supply target.

[0006] According to the present disclosure, a work machine is provided. The work machine includes a turning body, a work machine coupled to the turning body, and a power supply device capable of being connected to an external power source, for supplying power to a power supply target.

[0007] According to the present disclosure, it is possible to supply power to a power supply target. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a diagram showing a management system of a work machine of an embodiment.

[0009] Figure 2 is a diagram showing a shovel of an embodiment.

[0010] Figure 3 is a diagram showing a bulldozer of an embodiment.

[0011] Figure 4 is a diagram showing a dump truck of an embodiment.

[0012] Figure 5 is a diagram showing a control system of a work machine of an embodiment.

[0013] Figure 6 is a block diagram showing a management server and an on-vehicle controller of an embodiment.

[0014] Figure 7 is a diagram for explaining a first example of vehicle-to-vehicle charging of an embodiment.

[0015] Figure 8 is a diagram for explaining a second example of vehicle-to-vehicle charging of an embodiment.

[0016] Figure 9FIG. 1 is a diagram for explaining a first example of a vehicle-to-vehicle charging of the embodiment.

[0017] Figure 10 FIG. 2 is a diagram for explaining one example of a wired charging method of the embodiment.

[0018] Figure 11 FIG. 3 is a diagram for explaining one example of a wireless charging method of the embodiment.

[0019] Figure 12 FIG. 4 is a flowchart showing a management method of a work machine of the embodiment.

[0020] Figure 13 FIG. 5 is a diagram showing a shovel of the embodiment.

[0021] Figure 14 FIG. 6 is a diagram for explaining a charging method of a battery of the embodiment.

[0022] Figure 15 FIG. 7 is a diagram showing a shovel of the embodiment.

[0023] Figure 16 FIG. 8 is a diagram for explaining a charging method of a battery of the embodiment.

[0024] Figure 17 FIG. 9 is a diagram showing a shovel of the embodiment.

[0025] Figure 18 FIG. 10 is a diagram for explaining a charging method of a battery of the embodiment. DETAILED DESCRIPTION

[0026] Hereinafter, the embodiment of the present disclosure will be described with reference to the accompanying drawings, but the present disclosure is not limited to the embodiment. The constituent elements of the embodiment described below can be appropriately combined. In addition, there are cases where part of the constituent elements is not used.

[0027] First Embodiment

[0028] The first embodiment will be described.

[0029] Outline of Management System

[0030] Figure 1 FIG. 1 is a diagram showing a management system 1 of a work machine 2 of the embodiment. The management system 1 is for managing the work machines 2 working at a work site 3. In the embodiment, the work machines 2 are electric work machines powered by a battery. There are a plurality of work machines 2 in the work site 3. In the embodiment, the work machines 2 are shovels 2A, bulldozers 2B, and dump trucks 2C. Figure 1 In the example shown, the work machines 2 present in the work site 3 include shovels 2A, bulldozers 2B, and dump trucks 2C.

[0031] In this embodiment, no operator rides on the work machine 2. The work machine 2 is operated remotely. A remote control room 4 is located outside the work machine 2. The remote control room 4 is located at a remote location from the work site 3. An information terminal 5 and a remote control device 6 for remotely operating the work machine 2 are both located in the remote control room 4. Both the information terminal 5 and the remote control device 6 are located outside the work machine 2. The information terminal 5 includes a computer system located in the remote control room 4.

[0032] The remote control device 6 is operated by an operator in the remote control room 4. The operator's operation of the remote control device 6 generates operation signals for remotely operating the work machinery 2. The operation signals generated in the remote control device 6 are input into the information terminal 5. Based on the operation signals from the remote control device 6, the information terminal 5 generates remote operation commands. The information terminal 5 sends the remote operation commands to the work machinery 2 via the communication system 7.

[0033] The work machinery 2 operates based on remote operation commands sent from an information terminal 5 located external to the work machinery 2. At least one of the work machinery 2 and the work site 3 is equipped with a camera for acquiring image data of the work site 3. The image data of the work site 3 is sent to the information terminal 5 via a communication system 7 and displayed on the display device of the information terminal 5. The operator can operate the remote operation device 6 while confirming the image data of the work site 3.

[0034] The communication system 7 may include public communication lines or specific communication lines. Examples of communication system 7 include mobile phone communication networks or satellite communication networks. In addition, the communication system 7 may include the Internet or a local area network (LAN).

[0035] The management system 1 includes a management server 8. The management server 8 comprises a computer system. The management server 8 is capable of communicating with the operating machinery 2 via a communication system 7. The management server 8 is used to collect operational data from the operating machinery 2. The management server 8 is also used to output control commands to the operating machinery 2.

[0036] Operating machinery

[0037] Figure 2 This is a diagram showing an excavator 2A according to an embodiment. The excavator 2A includes: a slewing body 9, a traveling body 10, a working machine 11, and a working machine cylinder 12.

[0038] The slewing body 9 is supported on the traveling body 10 in a rotatable manner. The traveling body 10 moves while supporting the slewing body 9. The traveling body 10 has a pair of tracks 10A. The excavator 2A moves by rotating the tracks 10A.

[0039] The work machine 11 is connected to the slewing body 9. The work machine 11 includes: a boom 11A connected to the slewing body 9, a stick 11B connected to the boom 11A, and a bucket 11C connected to the stick 11B. The work machine cylinder 12 includes: a boom cylinder 12A for moving the boom 11A, a stick cylinder 12B for moving the stick 11B, and a bucket cylinder 12C for moving the bucket 11C.

[0040] Figure 3 This is a diagram showing a bulldozer 2B according to an embodiment. The bulldozer 2B includes: a body 13, a running gear 14, an excavator 15, a ripper 16, a working cylinder 17, and a ripper cylinder 18.

[0041] The vehicle body 13 is supported by the track body 14. The track body 14 moves while supporting the vehicle body 13. The track body 14 has a pair of tracks 14A. The bulldozer 2B moves by rotating the tracks 14A.

[0042] The excavator 15 is used to perform excavation, bulldozing, or leveling operations on a work object. The excavator 15 is mounted on a vehicle body 13. At least a portion of the excavator 15 is positioned at the front of the vehicle body 13. The excavator 15 includes a digging blade 15A. A working cylinder 17 is used to actuate the digging blade 15A.

[0043] The soil loosening machine 16 is used to perform soil loosening operations on a work surface. The work surface of the soil loosening machine 16 includes the ground of the work site. The soil loosening machine 16 is mounted on a vehicle body 13. At least a portion of the soil loosening machine 16 is located at the rear of the vehicle body 13. The soil loosening machine 16 includes loosening teeth 16A. A loosening cylinder 18 is used to actuate the loosening teeth 16A.

[0044] Figure 4 This is a diagram illustrating the implementation method of the dump truck 2C. (See diagram for example.) Figure 4 As shown, the dump truck 2C has: a body 19, a driving device 20, a truck bed 21, and a lifting cylinder 22.

[0045] The traveling device 20 includes multiple wheels 20A and a steering mechanism for steering the wheels 20A. A lifting cylinder 22 is used to raise and lower the truck bed 21. One end of the lifting cylinder 22 is rotatably connected to the vehicle body 19 via a bracket (not shown). The other end of the lifting cylinder 22 is rotatably connected to the truck bed 21 via a bracket (not shown). The truck bed 21 is a cargo loading component. The truck bed 21 is raised and lowered based on the operation of the lifting cylinder 22.

[0046] control system

[0047] Figure 5This is a diagram showing the control system 30 of the work machine 2 according to the embodiment. The work machine 2 has a control system 30. The control system 30 includes: a battery 31, a charging device 32, a DC / DC converter 33, an inverter 34, an electric motor 35, a hydraulic pump 36, a main valve 37, a hydraulic actuator 38, a power supply device 39, an on-board controller 40, a battery sensor 41, a position sensor 42, and a communication device 43.

[0048] The control system 30 includes: a control system 30A mounted on excavator 2A, a control system 30B mounted on bulldozer 2B, and a control system 30C mounted on dump truck 2C. Control systems 30A, 30B, and 30C have identical structures and functions.

[0049] The control system 30A of excavator 2A includes: battery 31A, charging device 32A, DC / DC converter 33A, inverter 34A, electric motor 35A, hydraulic pump 36A, main valve 37A, hydraulic actuator 38A, power supply device 39A, vehicle controller 40A, battery sensor 41A, position sensor 42A, and communication device 43A.

[0050] The control system 30B of the bulldozer 2B includes: a battery 31B, a charging device 32B, a DC / DC converter 33B, an inverter 34B, an electric motor 35B, a hydraulic pump 36B, a main valve 37B, a hydraulic actuator 38B, a power supply device 39B, an on-board controller 40B, a battery sensor 41B, a position sensor 42B, and a communication device 43B.

[0051] The control system 30C of the dump truck 2C includes: a battery 31C, a charging device 32C, a DC / DC converter 33C, an inverter 34C, an electric motor 35C, a hydraulic pump 36C, a main valve 37C, a hydraulic actuator 38C, a power supply device 39C, an on-board controller 40C, a battery sensor 41C, a position sensor 42C, and a communication device 43C.

[0052] Batteries 31A, 31B, and 31C have equivalent functions. In the following description, batteries 31A, 31B, and 31C may be collectively referred to as battery 31. The same applies to charging device 32, DC / DC converter 33, inverter 34, electric motor 35, hydraulic pump 36, main valve 37, hydraulic actuator 38, power supply device 39, vehicle controller 40, battery sensor 41, position sensor 42, and communication device 43.

[0053] Battery 31 is a built-in battery mounted on the working machine 2. Battery 31 includes a secondary battery. In this embodiment, battery 31 includes a lithium-ion battery (LiB).

[0054] The charging device 32 is connected to an external power source 23 located outside the working machinery 2. The external power source 23 includes at least one of the following: batteries 31 of other working machinery 2, a large battery pack located at the work site 3, and a charging station. The charging device 32 charges the batteries 31 based on the power supplied by the external power source 23.

[0055] DC / DC converter 33 boosts the voltage from battery 31. DC / DC converter 33 supplies DC power from battery 31 to inverter 34.

[0056] Inverter 34 converts direct current from DC / DC converter 33 into three-phase alternating current and supplies it to electric motor 35. Electric motor 35 is driven based on the three-phase alternating current supplied from inverter 34.

[0057] The electric motor 35 is the power source for the working machine 2. The electric motor 35 is driven by electricity from the battery 31.

[0058] Hydraulic pump 36 is driven by electric motor 35. Hydraulic pump 36 is used to discharge hydraulic oil. The hydraulic oil discharged from hydraulic pump 36 is supplied to hydraulic actuator 38 via main valve 37. Hydraulic actuator 38A of excavator 2A includes working cylinder 12. Hydraulic actuator 38B of bulldozer 2B includes working cylinder 17 and ripping cylinder 18. Hydraulic actuator 38C of dump truck 2C includes lifting cylinder 22.

[0059] Alternatively, an electric actuator can be installed in the working machine 2 to replace the hydraulic actuator 38. The working machine cylinder 12 can also be an electric cylinder. The working machine cylinder 17 and the ripping cylinder 18 can also be electric cylinders. The lifting cylinder 22 can also be an electric cylinder. When an electric actuator is installed in the working machine 2 to replace the hydraulic actuator 38, the hydraulic pump 36 and the main valve 37 can be omitted.

[0060] The power supply device 39 is connected to a power supply object 24 located outside the operating machinery 2. The power supply device 39 supplies power from the battery 31 to the power supply object 24. The power supply object 24 includes the batteries 31 of other operating machinery 2. The power supply device 39 charges the batteries 31 of other operating machinery 2 using the power supplied by the batteries 31.

[0061] The vehicle controller 40 includes a computer system. The vehicle controller 40 controls at least the charging device 32 and the power supply device 39.

[0062] Battery sensor 41 includes a voltage sensor for detecting the voltage of battery 31. Position sensor 42 is used to detect the position of the operating machinery 2. The position of the operating machinery 2 can be detected using a Global Navigation Satellite System (GNSS). GNSS includes the Global Positioning System (GPS). GNSS detects the position in a global coordinate system defined by coordinate data of latitude, longitude, and altitude. The global coordinate system is a coordinate system fixed on the Earth. Position sensor 42 includes a GNSS receiver. Position sensor 42 is used to detect the position of the operating machinery 2 in the global coordinate system. Communication device 43 is used for wireless communication with management server 8.

[0063] Management server and vehicle controller

[0064] Figure 6 This is a block diagram illustrating the management server 8 and vehicle controller 40 in an implementation scheme. Both the management server 8 and vehicle controller 40 include computer systems. The management server 8 includes: a processor 44, such as a CPU (Central Processing Unit); main memory 45, which includes non-volatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory); memory 46; and an interface 47, which includes input / output circuitry. The functions of the management server 8 are stored as a computer program in memory 46. The processor 44 reads the computer program from memory 46 and loads it into main memory 45, executing the processing according to the computer program. Furthermore, the computer program can also be transmitted to the management server 8 via a network.

[0065] The vehicle controller 40 includes: a processor 48, main memory 49, a storage device 50, and an interface 51.

[0066] The processor 48 includes: a remaining power calculation unit 48A, a position data transmission unit 48B, a charging control unit 48C, a power supply control unit 48D, and a walking control unit 48E.

[0067] The remaining power calculation unit 48A calculates the remaining power of battery 31 based on the detection data from battery sensor 41. The remaining power of battery 31 can also be considered as its State of Charge (SOC). The SOC refers to the ratio of remaining power to fully charged power. Battery sensor 41 is used to detect the voltage of battery 31. The remaining power calculation unit 48A can calculate the remaining power of battery 31 based on the detection data from battery sensor 41. The remaining power calculation unit 48A sends the calculated remaining power of battery 31 to management server 8. The remaining power of battery 31 is sent to management server 8 via communication system 7.

[0068] The position data transmission unit 48B acquires the detection data from the position sensor 42. The detection data from the position sensor 42 indicates the position of the operating machine 2. The position data transmission unit 48B transmits the acquired position of the operating machine 2 to the management server 8. The position of the operating machine 2 is transmitted to the management server 8 via the communication system 7.

[0069] The charging control unit 48C controls the charging device 32. The charging control unit 48C charges the battery 31 based on the power supply from the external power source 23.

[0070] The power supply control unit 48D is used to control the power supply device 39. The power supply control unit 48D supplies power to the power supply object 24 based on the power supply of the battery 31.

[0071] The travel control unit 48E controls the movement of the working machine 2. The travel control unit 48E of the vehicle controller 40A controls the traveling body 10. The travel control unit 48E of the vehicle controller 40B controls the traveling body 14. The travel control unit 48E of the vehicle controller 40C controls the traveling device 20.

[0072] The processor 44 includes a remaining power receiving unit 44A, a location data receiving unit 44B, and an allocation unit 44C. The memory 46 includes a job plan storage unit 46A.

[0073] The work plan storage unit 46A is used to store the work plans of each of the multiple machines 2. The work plans are, for example, formulated by the manager of the work site 3. The work plans are stored in the work plan storage unit 46A before the machines 2 start working at the work site 3.

[0074] The work plan is, for example, a daily work plan for machine 2. The work plan storage unit 46A stores, for example, the work plan for machine 2 from 9:00 AM to 5:00 PM.

[0075] The remaining power receiving unit 44A is used to acquire the remaining power of the batteries 31 of each of the multiple operating machines 2 present at the work site 3. The remaining power receiving unit 44A receives the remaining power of the batteries 31 sent by each of the multiple operating machines 2 present at the work site 3. Interface 47 is connected to the communication unit 52. The remaining power receiving unit 44A receives the remaining power of the batteries 31 sent from the operating machines 2 via the communication system 7 and the communication unit 52.

[0076] The position data receiving unit 44B is used to acquire the positions of the various operating machines 2 present in the work site 3. The position data receiving unit 44B receives the positions of the operating machines 2 transmitted by the operating machines 2. The position data receiving unit 44B receives the positions of the operating machines 2 transmitted by the operating machines 2 via the communication system 7 and the communication device 52.

[0077] The distribution unit 44C outputs a charging command, based on the remaining power of the batteries 31 of each of the multiple working machines 2, instructing the second working machine 2 to charge the battery 31 of the first working machine 2. The distribution unit 44C outputs the charging command so that the battery 31 of the first working machine 2 requiring charging is charged by the second working machine 2, which has a battery 31 capable of charging the battery 31 of the first working machine 2. The distribution unit 44C outputs the charging command, for example, so that the battery 31 of the first working machine 2 with a smaller remaining power is charged by the second working machine 2 equipped with a battery 31 having a larger remaining power.

[0078] The distribution unit 44C can also output a charging command based on the remaining power of the batteries 31 of each of the multiple working machines 2 and the position of each of the multiple working machines 2, so as to charge the batteries 31 of the first working machine 2 through the second working machine 2.

[0079] The distribution unit 44C can also output a charging command based on the remaining power of the batteries 31 of each of the multiple operating machines 2 and the operation plan of each of the multiple operating machines 2, so as to charge the batteries 31 of the first operating machine 2 through the second operating machine 2.

[0080] The distribution unit 44C can also output a charging command based on the remaining power of the batteries 31 of each of the multiple working machines 2 and the operating status of each of the multiple working machines 2, so as to charge the batteries 31 of the first working machine 2 through the second working machine 2.

[0081] Car-to-car charging

[0082] In this implementation, at the work site 3, the battery 31 of the first working machine 2 that needs charging is charged by a second working machine 2 having a battery 31 capable of charging the battery 31 of the first working machine 2. The remaining power receiving unit 44A of the management server 8 is used to acquire the remaining power of the batteries 31 of each of the multiple working machines 2 present at the work site 3. Based on the remaining power of the batteries 31 of each of the multiple working machines 2, the remaining power receiving unit 44A determines whether there is a first working machine 2 whose battery 31 needs charging. Based on the remaining power of the batteries 31 of each of the multiple working machines 2, the remaining power receiving unit 44A determines whether there is a second working machine 2 having a battery 31 capable of charging the battery 31 of the first working machine 2. When it is determined that both the first working machine 2 and the second working machine 2 exist, the distribution unit 44C outputs a charging command that causes the second working machine 2 to charge the battery 31 of the first working machine 2.

[0083] First Example

[0084] For example, in work site 3, the battery 31 of the first working machine 2 with less remaining power is charged by the second working machine 2 with more remaining power.

[0085] Before the operating machine 2 begins operation, its battery 31 is charged at the charging station. The battery 31 is fully charged at the charging station. After the battery 31 is fully charged, the operating machine 2 operates at the work site 3. As the operating machine 2 operates at the work site 3, it consumes the power of the battery 31, and the remaining power of the battery 31 gradually decreases.

[0086] For example, depending on the work content of the operating machinery 2, even if the working time is the same, there may be differences in the remaining power of the battery 31 among multiple operating machinery 2. For instance, if multiple operating machinery 2 work at the work site 3 from 9:00 AM to 5:00 PM, at 1:00 PM, there may be operating machinery 2 with more remaining battery 31 power and operating machinery 2 with less remaining battery 31 power. If a charging station is not present at the work site 3, it is difficult to charge the battery 31 at the charging station after the work begins.

[0087] In this implementation, power is transferred between multiple operating machines 2. The operating machine 2 equipped with a battery 31 having a large remaining charge charges the battery 31 of the operating machine 2 with a small remaining charge.

[0088] Figure 7This diagram illustrates a first example of vehicle-to-vehicle charging in an implementation embodiment. The remaining power receiving unit 44A of the management server 8 acquires the remaining power of the batteries 31 of each of the multiple work machines 2 present at the work site 3. The remaining power receiving unit 44A determines whether there is a first work machine 2 whose battery 31 has a remaining power below a preset first threshold.

[0089] When it is determined that there is a first working machine 2 with a low remaining power of battery 31, the remaining power receiving unit 44A determines whether there is a second working machine 2 with a battery 31 having a higher remaining power than the battery 31 of the first working machine 2.

[0090] exist Figure 7 In the example shown, bulldozer 2B is a first working machine 2 whose remaining battery power 31B is below a first threshold. Dump truck 2C is a second working machine 2 with a battery 31C having a greater remaining battery power than the remaining battery power of the bulldozer 2B's battery 31B. The distribution unit 44C determines that bulldozer 2B, whose remaining battery power 31B is below the first threshold, is a first working machine 2 whose battery 31B needs charging. The distribution unit 44C determines that dump truck 2C, whose battery 31C has a greater remaining battery power than the remaining battery power of the bulldozer 2B's battery 31B, is a second working machine 2 with a battery 31 capable of charging the bulldozer 2B's battery 31B. When it is determined that there is both bulldozer 2B as a first working machine 2 and dump truck 2C as a second working machine 2, the distribution unit 44C outputs a charging command to cause dump truck 2C to charge the bulldozer 2B's battery 31B.

[0091] The charging command output from the distribution unit 44C is sent to the on-board controller 40C of the dump truck 2C. The travel control unit 48E of the dump truck 2C controls the driving device 20 of the dump truck 2C to move closer to the bulldozer 2B based on the position of the bulldozer 2B. When the dump truck 2C approaches the bulldozer 2B, the power supply control unit 48D of the dump truck 2C controls the power supply device 39C to charge the battery 31B of the bulldozer 2B.

[0092] When there are multiple second working machines 2 at the work site 3 with batteries 31 having more remaining power than the bulldozer 2B's battery 31B, the distribution unit 44C causes the second working machine 2 with the battery 31 having the most remaining power to charge the bulldozer 2B's battery 31B. When there are multiple dump trucks 2C at the work site 3 with batteries 31C having a relatively large amount of remaining power, the distribution unit 44C causes the dump truck 2C with the battery 31C having the most remaining power to charge the bulldozer 2B's battery 31B.

[0093] Second example

[0094] Figure 8This diagram illustrates a second example of vehicle-to-vehicle charging in an implementation embodiment. The remaining power receiving unit 44A of the management server 8 acquires the remaining power of the batteries 31 of each of the multiple work machines 2 present at the work site 3. The remaining power receiving unit 44A determines whether there is a first work machine 2 whose battery 31 has a remaining power below a preset first threshold.

[0095] When it is determined that there is a first working machine 2 with a low remaining power of battery 31, the remaining power receiving unit 44A determines whether there is a second working machine 2 with a battery 31 having a higher remaining power than the battery 31 of the first working machine 2.

[0096] exist Figure 8 In the example shown, bulldozer 2B is a first working machine 2 whose remaining battery power 31B is below a threshold. Dump trucks 2C1 and 2C2 are second working machines 2 with batteries 31C having a greater remaining battery power than the remaining battery power of the bulldozer 2B's battery 31B.

[0097] The location data receiving unit 44B is used to acquire the positions of the multiple operating machines 2 present in the work site 3. When it is determined that there are multiple dump trucks 2C as second operating machines 2, the distribution unit 44C determines the dump truck 2C that will charge the battery 31C of the bulldozer 2B based on the position of the bulldozer 2B and the positions of the multiple dump trucks 2C (2C1, 2C2).

[0098] Based on the position of the bulldozer 2B and the respective positions of the multiple dump trucks 2C (2C1, 2C2), the distribution unit 44C calculates the distance between the bulldozer 2B and each of the multiple dump trucks 2C (2C1, 2C2). The distribution unit 44C then enables the dump truck 2C with the shortest distance to the bulldozer 2B to charge the battery 31B of the bulldozer 2B.

[0099] exist Figure 8 In the example shown, the distribution unit 44C calculates a first distance between bulldozer 2B and dump truck 2C1 based on the positions of bulldozer 2B and dump truck 2C1. The distribution unit 44C also calculates a second distance between bulldozer 2B and dump truck 2C2 based on their respective positions. When the first distance is shorter than the second distance, the distribution unit 44C outputs a charging command to cause dump truck 2C1 to charge the battery 31B of bulldozer 2B.

[0100] Third Example

[0101] Figure 9This diagram illustrates a third example of vehicle-to-vehicle charging in an implementation method. The remaining power receiving unit 44A of the management server 8 acquires the remaining power of the batteries 31 of each of the multiple work machines 2 present at the work site 3. The allocation unit 44C acquires the work plans of each of the multiple work machines 2 present at the work site 3. The remaining power receiving unit 44A determines whether there is a first work machine 2 whose remaining battery 31 power is below a preset first threshold.

[0102] When it is determined that there is a first working machine 2 with a low remaining power of battery 31, the remaining power receiving unit 44A determines whether there is a second working machine 2 with a battery 31 having a higher remaining power than the battery 31 of the first working machine 2.

[0103] exist Figure 9 In the example shown, bulldozer 2B is a first working machine 2 whose remaining battery power 31B is below a first threshold. Dump trucks 2C3 and 2C4 are second working machines 2 with batteries 31C having a remaining battery power greater than that of the bulldozer 2B's battery 31B.

[0104] When it is determined that there are multiple dump trucks 2C acting as the second operating machinery 2, the distribution unit 44C calculates the predicted power consumption of each dump truck 2C based on its respective operating plan. Based on the predicted power consumption of the multiple dump trucks 2C (2C3, 2C4), the distribution unit 44C determines which dump truck 2C will charge the battery 31B of the bulldozer 2B.

[0105] For example, when charging the battery 31B of bulldozer 2B at 1 PM, the distribution unit 44C predicts the electricity consumption of dump truck 2C3 from 1 PM to 5 PM based on the work plan of dump truck 2C3 from 1 PM to 5 PM. The distribution unit 44C also predicts the electricity consumption of dump truck 2C4 from 1 PM to 5 PM based on the work plan of dump truck 2C4 from 1 PM to 5 PM.

[0106] The power consumption of battery 31 varies depending on the operation of the machinery 2. For example, if the dump truck 2C3 is expected to perform fewer transport operations between 1 p.m. and 5 p.m., the predicted power consumption of dump truck 2C3 will be lower. If the dump truck 2C4 is expected to perform more transport operations between 1 p.m. and 5 p.m., the predicted power consumption of dump truck 2C4 will be higher.

[0107] The distribution unit 44C uses the dump truck 2C, which has the lowest predicted power level, to charge the battery 31B of the bulldozer 2B.

[0108] exist Figure 9In the example shown, the distribution unit 44C calculates a first predicted value for the power consumption of dump truck 2C3 based on the work plan of dump truck 2C3. The distribution unit 44C calculates a second predicted value for the power consumption of dump truck 2C4 based on the work plan of dump truck 2C4. When the first predicted value is smaller than the second predicted value, the distribution unit 44C outputs a charging command to cause dump truck 2C3 to charge the battery 31B of bulldozer 2B. Because the predicted power consumption of dump truck 2C3 is small, even if the battery 31C of dump truck 2C3 supplies power to the battery 31B of bulldozer 2B, dump truck 2C3 can still operate until 5 PM.

[0109] Furthermore, when it is determined that there are multiple dump trucks 2C acting as second operating machinery 2, the distribution unit 44C can also calculate the predicted value of the remaining power of the battery 31C of each dump truck 2C when it finishes its work, based on the respective work plans of each dump truck 2C. The distribution unit 44C can also determine which dump truck 2C will charge the battery 31B of the bulldozer 2B based on the predicted value of the remaining power of the battery 31C of each dump truck 2C (2C3, 2C4) when it finishes its work. The distribution unit 44C ensures that the dump truck 2C with the highest predicted value of the remaining power of its battery 31C charges the battery 31B of the bulldozer 2B.

[0110] Based on the individual work plans of multiple dump trucks 2C (2C3, 2C4), the distribution unit 44C calculates a predicted value for the remaining battery power of the multiple dump trucks 2C (2C3, 2C4) at, for example, 5 PM. Based on the work plan of dump truck 2C3, the distribution unit 44C calculates a third predicted value for the remaining battery power of dump truck 2C3 at 5 PM when dump truck 2C3 finishes its work. Based on the work plan of dump truck 2C4, the distribution unit 44C calculates a fourth predicted value for the remaining battery power of dump truck 2C4 at 5 PM when dump truck 2C4 finishes its work. When the third predicted value is greater than the fourth predicted value, the distribution unit 44C outputs a charging command to cause dump truck 2C3 to charge the battery 31B of bulldozer 2B. Because the predicted remaining power of the battery 31C of the dump truck 2C3 is relatively large, the dump truck 2C3 can work until 5 p.m. even if the battery 31C of the dump truck 2C3 supplies power to the battery 31B of the bulldozer 2B.

[0111] Fourth example

[0112] Furthermore, when there are multiple second working machines 2, the distribution unit 44C can also determine the second working machine 2 that charges the battery 31 of the first working machine 2 based on the working data of each of the multiple second working machines 2.

[0113] As described above, the management server 8 collects operational data from the machine 2. This operational data includes the operational status of the machine 2, specifically whether it is currently operating or not. The machine 2 is equipped with a status sensor for detecting operational data. The distribution unit 44C can determine whether the machine 2 is operating or not based on the data detected by the status sensor.

[0114] The distribution unit 44C can also determine which second working machine 2 should charge the battery 31 of the first working machine 2 based on the working data of each of the multiple second working machines 2. As described above, the management server 8 collects the working data of the working machines 2. The working data includes the working status of the working machine 2. The working status includes whether the working machine 2 is working or resting. The working machine 2 is equipped with a status sensor for detecting the working data. The distribution unit 44C can determine whether the working machine 2 is working or resting based on the detection data of the status sensor. The distribution unit 44C can also output a charging command, for example, to cause the resting second working machine 2 to charge the battery 31 of the first working machine 2.

[0115] Fifth example

[0116] The distribution unit 44C can also determine whether there is a first machine 2 whose battery 31 needs charging based on the scheduled tasks of each of the multiple machines 2 and the remaining power of the battery 31. The scheduled tasks of each of the multiple machines 2 are determined based on the work plan described above. The distribution unit 44C can also identify machines 2 whose battery 31 is determined to be depleted before the scheduled task ends as the first machine 2 whose battery 31 needs charging. The distribution unit 44C determines whether the remaining power of the battery 31 will be depleted before the scheduled task ends based on the time or load required for the scheduled task. The longer the scheduled task takes, the higher the probability that the remaining power of the battery 31 will be depleted by the end of the scheduled task. The greater the load required for the scheduled task, the higher the probability that the remaining power of the battery 31 will be depleted by the end of the scheduled task. The distribution unit 44C identifies machines 2 whose battery 31 is determined to be depleted before the scheduled task ends as the first machine 2 whose battery 31 needs charging based on the time or load required for the scheduled task.

[0117] Sixth example

[0118] The distribution unit 44C can also determine that a working machine with a remaining battery power of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 31 of 32 ...

[0119] Seventh Example

[0120] The distribution unit 44C can also determine whether there is a second working machine 2 with a battery 31 capable of charging the battery 31 of the first working machine 2, based on the scheduled tasks of each of the multiple working machines 2 and the remaining power of the battery 31. The scheduled tasks of each of the multiple working machines 2 are determined based on the work plan described above. The distribution unit 44C can also determine whether a working machine 2, which is determined to have remaining power in its battery 31 at the end of the scheduled task, is a second working machine 2 with a battery 31 capable of charging the battery 31 of the first working machine 2. The distribution unit 44C determines whether there is remaining power in the battery 31 at the end of the scheduled task based on the time or load required for the scheduled task. The shorter the time required for the scheduled task, the higher the probability that there will be remaining power in the battery 31 at the end of the scheduled task. The smaller the load required for the scheduled task, the higher the probability that there will be remaining power in the battery 31 at the end of the scheduled task. Based on the time or load required for the scheduled task, the distribution unit 44C determines whether a working machine 2, which is determined to have remaining power in its battery 31 at the end of the scheduled task, is a second working machine 2 with a battery 31 capable of charging the battery 31 of the first working machine 2.

[0121] Eighth Example

[0122] Alternatively, without relying on charging commands from the distribution unit 44C, the onboard controller 40 of the second working machine 2 can obtain the remaining power of the batteries 31 of other working machines 2 present in the work site 3, and determine whether there are other working machines 2 whose batteries 31 need charging. When it is determined that there are other working machines 2 whose batteries 31 need charging, the onboard controller 40 of the second working machine 2 outputs a charging command to charge the batteries 31 of the other working machines 2. For example, a charging working machine 2 (second working machine 2) equipped with a large-capacity battery 31 can be configured in the work site 3. This charging working machine 2 collects the remaining power of the batteries 31 of other working machines 2 present in the work site 3 and charges the batteries 31 of other working machines 2 with less remaining power.

[0123] Charging method

[0124] When the dump truck 2C charges the battery 31B of the bulldozer 2B, the dump truck 2C can charge the battery 31B of the bulldozer 2B by wire or wirelessly.

[0125] Figure 10This diagram illustrates a method for charging battery 31B using a wired charging method according to the embodiment. The power supply control unit 48D of the dump truck 2C performs wired charging of battery 31B of bulldozer 2B based on a charging command received from the distribution unit 44C. The base of the power supply arm 25 is connected to the power supply device 39C of the dump truck 2C. The front end of the power supply arm 25 is connected to the charging port of bulldozer 2B. The charging port of bulldozer 2B is connected to the charging device 32B of bulldozer 2B. With the power supply arm 25 connected to the charging port of bulldozer 2B, the power supply device 39C of the dump truck 2C supplies power to the charging device 32B of bulldozer 2B. The power supply device 39C supplies power from battery 31C to charging device 32B via power supply arm 25. By supplying power from battery 31C of dump truck 2C to charging device 32B, battery 31B of bulldozer 2B is charged.

[0126] Figure 11 This diagram illustrates an example of a wireless charging method for an implementation. The power supply control unit 48D of the dump truck 2C wirelessly charges the battery 31B of the bulldozer 2B based on a charging command received from the distribution unit 44C. The dump truck 2C is equipped with a wireless power supply unit 26C, and the bulldozer 2B is equipped with a wireless receiver 26B. In the dump truck 2C, the wireless power supply unit 26C is connected to a power supply device 39C. In the bulldozer 2B, the wireless receiver 26B is connected to a charging device 32B. The power supply device 39C supplies power from the battery 31C to the wireless power supply unit 26C. The wireless power supply unit 26C wirelessly supplies power from the battery 31C to the wireless receiver 26B. The power supplied to the wireless receiver 26B is then supplied to the charging device 32B. By supplying power from the battery 31C of the dump truck 2C to the charging device 32B, the battery 31B of the bulldozer 2B is charged.

[0127] Management methods

[0128] Figure 12 This is a flowchart illustrating the management method of the operating machinery 2 according to the implementation method. The remaining power receiving unit 44A of the management server 8 receives the remaining power of the batteries 31 of each of the multiple operating machinery 2 present in the work site 3 (step S1).

[0129] The remaining power receiving unit 44A determines whether there is a first operating machine 2 whose remaining power of battery 31 is below a preset threshold (step S2).

[0130] If it is determined in step S2 that the first working machine 2 does not exist (step S2: No), the process returns to step S1. If it is determined in step S2 that the first working machine 2 exists (step S2: Yes), the remaining power receiving unit 44A determines whether there is a second working machine 2 with a battery 31 having more remaining power than the battery 31 of the first working machine 2 (step S3).

[0131] If it is determined in step S3 that the second working machine 2 does not exist (step S3: No), the process returns to step S1. If it is determined in step S3 that the second working machine 2 exists (step S3: Yes), the position data receiving unit 44B receives the position of the first working machine 2 and the position of the second working machine 2 in the work site 3 (step S4).

[0132] The distribution unit 44C obtains the work plan of the second machine 2 from the work plan storage unit 46A. Based on the work plan, the distribution unit 44C predicts the power consumption of the second machine 2 (step S5).

[0133] When multiple second working machines 2 exist, the distribution unit 44C determines the second working machine 2 that will charge the battery 31 of the first working machine 2 based on the positions of the first working machine 2 and the second working machine 2. In addition, the distribution unit 44C determines the second working machine 2 that will charge the battery 31 of the first working machine 2 based on the predicted power consumption of the second working machine 2 (step S6).

[0134] The distribution unit 44C outputs a charging command to cause the second working machine 2, determined in step S6, to charge the battery 31 of the first working machine 2 (step S7).

[0135] The distribution unit 44C sends a charging command to the on-board controller 40 of the second working machine 2 determined in step S6. After receiving the charging command, the on-board controller 40 causes the second working machine 2 to move closer to the first working machine 2, and then causes the power supply device 39 of the second working machine 2 to supply power to the charging device 32 of the first working machine 2.

[0136] Furthermore, the distribution unit 44C can also send a charging command to the information terminal 5 used for remote operation of the working machine 2. When the charging command is received by the information terminal 5, a message indicating receipt of the charging command is displayed on the information terminal 5's screen. After confirming the message on the display, the operator can remotely operate the working machine 2 to charge the battery 31 of the first working machine 2.

[0137] Effect

[0138] As described above, according to the embodiment, multiple work machines 2 present at the work site 3 perform vehicle-to-vehicle charging. The battery 31 of the first work machine 2 that needs charging is charged by a second work machine 2 having a battery 31 capable of charging the battery 31 of the first work machine 2. Thus, for example, even if there is no charging station at or near the work site 3, the battery 31 of the first work machine 2 can be charged. Therefore, the first work machine 2 can continue to operate.

[0139] Second Implementation Method

[0140] The second embodiment will be described. In the following description, the same or equivalent components as those in the first embodiment described above will be marked with the same symbols, and the description of these components will be simplified or omitted.

[0141] Management methods

[0142] Figure 13 This is a diagram illustrating the implementation of excavator 2A. Figure 13 In the example shown, excavator 2A is connected to an external power source 27. The external power source 27 is either AC power or a large battery pack. The charging device 32A of excavator 2A is connected to the external power source 27 via cable 28. The power supply device 39A of excavator 2A can be connected to the external power source 27. In this embodiment, the power supply device 39A of excavator 2A is connected to the external power source 27 via battery 31A, charging device 32A, and cable 28.

[0143] The power supply unit 39A of excavator 2A supplies power to the dump truck 2C while the charging device 32A is connected to the external power source 27 via cable 28. In this embodiment, the power supply unit 39A of excavator 2A supplies power to the dump truck 2C while receiving power from the external power source 27 to the charging device 32A via cable 28. The battery 31C of dump truck 2C is charged by the power supplied from excavator 2A.

[0144] Figure 14 This diagram illustrates the charging method of battery 31C according to the embodiment. Excavator 2A uses work machine 11 to perform a loading operation, loading goods onto dump truck 2C which has battery 31C. Figure 14 As shown, during the loading operation, dump truck 2C enters the loading position next to excavator 2A. During the loading operation, dump truck 2C stops at the loading position.

[0145] The power supply unit 39A of excavator 2A supplies power to dump truck 2C during loading operations. Figure 14In the example shown, power supply unit 39A provides wired power to dump truck 2C. The base of power supply arm 29 is connected to power supply unit 39A of excavator 2A. The base of power supply arm 29 is connected to the traveling body 10. Power supply arm 29 extends from the traveling body 10. The front end of power supply arm 29 is connected to the charging port of dump truck 2C. The charging port of dump truck 2C is connected to charging device 32C of dump truck 2C. With power supply arm 29 connected to the charging port of dump truck 2C, power supply unit 39A of excavator 2A supplies power to charging device 32C of dump truck 2C. Power supply unit 39A of excavator 2A supplies power from battery 31A to charging device 32C via power supply arm 29. Power from battery 31A of excavator 2A is supplied to charging device 32C of dump truck 2C, allowing battery 31C of dump truck 2C to be charged.

[0146] During loading operations, the dump truck 2C is parked at the loading position. During loading operations, the slewing body 9 and the workpiece 11 of the excavator 2A move, but the traveling body 10 remains essentially stationary. Additionally, the power boom 29 extends from the traveling body 10. Therefore, during loading operations, the excavator 2A can charge the battery 31C of the dump truck 2C.

[0147] After loading is completed, the power supply arm 29 disengages from the charging port of the dump truck 2C. After disengagement, the dump truck 2C begins to move and exits the loading position. After the dump truck 2C exits the loading position, another dump truck 2C enters the loading position. The excavator 2A begins loading cargo onto the next dump truck 2C. During loading, the power supply arm 29 is connected to the charging port of the dump truck 2C, allowing the battery 31C of the dump truck 2C to be charged.

[0148] The charging device 32A of excavator 2A is connected to an external power source 27 via cable 28. The charging device 32A continuously or periodically charges the battery 31A of excavator 2A using power from the external power source 27. Thus, excavator 2A can charge the batteries 31C of multiple dump trucks 2C using power from battery 31A.

[0149] Effect

[0150] As described above, the power supply unit 39A of excavator 2A supplies power to the dump truck 2C when the charging unit 32A is connected to the external power source 27. The battery 31A of excavator 2A is charged using power supplied by the external power source 27. By supplying power from the battery 31A of excavator 2A to the dump truck 2C, the battery 31C of the dump truck 2C is charged. The charging unit 32A of excavator 2A continuously or periodically charges the battery 31A of excavator 2A using power from the external power source 27. Thus, excavator 2A can sequentially charge the batteries 31C of multiple dump trucks 2C using power from the battery 31A.

[0151] During loading operations, the dump truck 2C is parked in one location, allowing the excavator 2A to smoothly charge the battery 31C of the dump truck 2C. The dump truck 2C may remain stationary for several minutes during loading operations. The dump truck 2C is able to charge the battery 31C during this parking period.

[0152] Third Implementation Method

[0153] The third embodiment will be described. In the following description, the same or equivalent components as those in the first embodiment described above will be marked with the same symbols, and the description of these components will be simplified or omitted.

[0154] Figure 15 This is a diagram illustrating the excavator 2A as described in the embodiment. (As shown) Figure 15 As shown, the charging device 32A of the excavator 2A is connected to the external power supply 27 via cable 28.

[0155] The power supply unit 39A of the excavator 2A is connected to the traveling robot 60 via cable 62. The traveling robot 60 has a power supply arm 61. Power from the battery 31A is supplied to the power supply arm 61 via the power supply unit 39A, cable 62, and traveling robot 60. The power supply unit 39A provides power when the power supply arm 61 of the traveling robot 60 is connected to the charging port of the dump truck 2C.

[0156] Figure 16 This is a diagram illustrating the charging method of battery 31C according to the embodiment. During loading operations, dump truck 2C is parked at the loading position.

[0157] The power supply unit 39A of excavator 2A supplies power to dump truck 2C during loading operations. During loading, the traveling robot 60 moves to the vicinity of dump truck 2C. After approaching the charging port of dump truck 2C, the traveling robot 60 connects the front end of its power supply arm 61 to the charging port. With the power supply arm 61 connected to the charging port of dump truck 2C, the power supply unit 39A of excavator 2A supplies power to the charging device 32C of dump truck 2C. The power supply unit 39A of excavator 2A supplies power from battery 31A to charging device 32C via cable 62, traveling robot 60, and power supply arm 61. Power from battery 31A of excavator 2A is supplied to the charging device 32C of dump truck 2C, allowing battery 31C of dump truck 2C to be charged.

[0158] After loading is completed, the power supply arm 61 disengages from the charging port of the dump truck 2C. After the power supply arm 61 disengages from the charging port, the dump truck 2C begins to move and exits from the loading position.

[0159] Fourth Implementation Method

[0160] The fourth embodiment will be described. In the following description, the same or equivalent components as those in the first embodiment described above will be marked with the same symbols, and the description of these components will be simplified or omitted.

[0161] Figure 17 This is a diagram illustrating the excavator 2A as described in the embodiment. (As shown) Figure 17 As shown, the charging device 32A of the excavator 2A is connected to the external power supply 27 via cable 28.

[0162] In this embodiment, the power supply unit 39A of the excavator 2A wirelessly powers the dump truck 2C. The power supply unit 39A of the excavator 2A is connected to the charging station 63 via cable 64. Power from the battery 31A is supplied to the charging station 63 via the power supply unit 39A and cable 62.

[0163] Figure 18 This diagram illustrates the charging method for battery 31C according to the embodiment. A charging platform 63 is provided at the loading position. The charging platform 63 is located on the ground. A dump truck 2C enters the loading position by crossing the charging platform 63. During loading operations, the dump truck 2C stops at the loading position. The dump truck 2C is positioned above the charging platform 63.

[0164] The power supply unit 39A of excavator 2A supplies power to dump truck 2C during loading operations. The power supply unit 39A of excavator 2A supplies power to charging platform 63 when dump truck 2C is positioned above charging platform 63. The power supply unit 39A of excavator 2A supplies power from battery 31A to charging platform 63 via cable 64.

[0165] Charging station 63 charges battery 31C of dump truck 2C. Charging station 63 can be a contact charging station that charges battery 31C by contacting at least a portion of dump truck 2C, or a contactless charging station (wireless charging station) that charges battery 31C without contacting dump truck 2C. The contact charging station has a power supply terminal connected to a power receiving terminal provided on dump truck 2C. The contact charging station enables fast charging of battery 31C. The wireless charging station wirelessly charges battery 31C of dump truck 2C. By positioning dump truck 2C above the wireless charging station, the distance between the wireless charging station and battery 31C of dump truck 2C can be shortened. Therefore, the wireless charging station can wirelessly charge battery 31C of dump truck 2C.

[0166] After the loading operation is completed, the dump truck 2C starts to move and exits from the loading position. Once the dump truck 2C has exited the loading position and the charging platform 63 is away from the dump truck 2C, the charging of the battery 31C ends.

[0167] Symbol Explanation

[0168] 1…Management system; 2…Operating machinery; 2A…Excavator; 2B…Bulldozer; 2C…Dump truck; 2C1…Dump truck; 2C2…Dump truck; 2C3…Dump truck; 2C4…Dump truck; 3…Work site; 4…Remote control room; 5…Information terminal; 6…Remote control device; 7…Communication system; 8…Management server; 9…Slewing body; 10…Walking body; 10A…Crawler; 11…Working machine; 11A…Boom; 11B…Stick; 11C…Bucket; 12…Working machine cylinder; 12A…Boom cylinder; 12B…Stick cylinder; 12C…Bucket cylinder; 13…Body; 14…Walking body; 14A…Crawler; 15…Excavating machine; 15A…Excavating shovel; 16…Soil loosening machine; 16A…Soil loosening teeth; 17… …Working machine cylinder; 18…Soil loosening cylinder; 19…Body; 20…Travel device; 20A…Wheel; 21…Cargo bed; 22…Lifting cylinder; 23…External power supply; 24…Powered object; 25…Powering arm; 26B…Wireless receiver; 26C…Wireless power supply; 27…External power supply; 28…Cable; 29…Powering arm; 30…Control system; 30A…Control system; 30B…Control system; 30C…Control system; 31…Battery; 31A…Battery; 31B…Battery; 31C…Battery; 32…Charging device; 32A…Charging device; 32B…Charging device; 32C…Charging device; 33…DC / DC converter; 33A…DC / DC converter; 33B…DC / DC converter; 33C…DC / DC converter …DC / DC converter; 34…Inverter; 34A…Inverter; 34B…Inverter; 34C…Inverter; 35…Electric motor; 35A…Electric motor; 35B…Electric motor; 35C…Electric motor; 36…Hydraulic pump; 36A…Hydraulic pump; 36B…Hydraulic pump; 36C…Hydraulic pump; 37…Main valve; 37A…Main valve; 37B…Main valve; 37C…Main valve; 38…Hydraulic actuator; 38A…Hydraulic actuator; 38B…Hydraulic actuator; 38C…Hydraulic actuator; 39…Power supply unit; 39A…Power supply unit; 39B…Power supply unit; 39C…Power supply unit; 40…On-board controller; 40A…On-board controller; 40B…On-board controller; 40C…On-board controller 41… Battery sensor; 41A… Battery sensor; 41B… Battery sensor; 41C… Battery sensor; 42… Position sensor; 42A… Position sensor; 42B… Position sensor; 42C… Position sensor; 43… Communicator; 43A… Communicator; 43B… Communicator; 43C… Communicator; 44… Processor; 44A… Remaining power receiving unit; 44B… Position data receiving unit; 44C… Distribution unit; 45… Main memory; 46… Memory; 46A… Job plan storage unit; 47… Interface; 48… Processor; 48A… Remaining power calculation unit; 48B… Position data transmission unit; 48C… Charging control unit; 48D… Power supply control unit; 48E… Walking control unit; 49… Main memory;50… Memory; 51… Interface; 52… Communicator; 60… Traveling robot; 61… Power supply arm; 62… Cable; 63… Charging station; 64… Cable.

Claims

1. A work machine characterized by, Possessing: a revolving body; a work machine linked to the revolving body; and a power supply device capable of connecting with an external power source, for supplying power to a power supply target.

2. The work machine according to claim 1, wherein the power supply device is connected with the external power source via a cable.

3. The work machine according to claim 1, wherein the power supply device supplies power to the power supply target in a state of being supplied with power by the external power source.

4. The work machine of claim 1, wherein, Possessing: a battery, the power supply device supplies power from the battery to the power supply target.

5. The work machine according to claim 1, wherein a loading work of loading a cargo to a self-unloading vehicle having a battery is performed using the work machine, the power supply target is the self-unloading vehicle, the power supply device supplies power to the self-unloading vehicle during the loading work.

6. The work machine according to claim 5, wherein the power supply device supplies power to the self-unloading vehicle by wire.

7. A work machine according to claim 6, characterised in that Possessing: a power supply arm connected with the power supply device, the power supply device supplies power in a state that the power supply arm is connected with a charging port of the self-unloading vehicle.

8. The work machine according to claim 6, wherein the power supply device is connected with a traveling robot, the power supply device supplies power in a state that a power supply arm of the traveling robot is connected with a charging port of the self-unloading vehicle.

9. The work machine according to claim 5, wherein the power supply device supplies power to the self-unloading vehicle by wireless.

10. The work machine according to claim 5, wherein the power supply device is connected with a charging table, the power supply device supplies power in a state that the self-unloading vehicle is positioned above the charging table.

11. The work machine according to claim 10, wherein the charging table is a wireless charging table.

12. A method of charging a battery, characterized by, Including: supplying power from an external power source to a work machine having a revolving body and a work machine supported to the revolving body; and in a loading work of loading a cargo to a self-unloading vehicle by the work machine, the work machine charges a battery of the self-unloading vehicle.

13. A method of charging a battery, characterized by, Including: charging a battery of a work machine using power supplied from an external power source, the work machine having a revolving body and a work machine linked to the revolving body; and charging the battery of the self-unloading vehicle by supplying power from the battery to the self-unloading vehicle.

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