Power supply device

Abstract

To provide a power supply device for charging an on-vehicle battery of a working machine without using a commercial power supply at the work site of the working machine.SOLUTION: A power supply device 6 includes an input circuit 17 to which DC power is input from a plurality of storage batteries 2, a power conversion circuit 18 that converts the DC power input to the input unit 17 into AC power, and an output circuit 19 that outputs AC power, and the output circuit 19 outputs AC power to a charging device 11 that charges a vehicle battery 4. The charging device 11 charges the vehicle battery 4 on the basis of the AC power input from the output circuit 19.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a power supply device.

Background Art

[0002] In the technical field related to power supply devices, a power supply device as disclosed in Patent Document 1 is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An electric working machine has an in-vehicle battery. There is a demand for a technology that can charge the in-vehicle battery without using commercial power at the work site of the working machine. In addition, a technology that can charge in-vehicle batteries with different characteristics is demanded.

[0005] The present disclosure aims to charge an in-vehicle battery mounted on a working machine.

Means for Solving the Problems

[0006] According to the present disclosure, there is provided a power supply device including an input unit to which DC power is input from a storage battery, a power conversion unit that converts the DC power input to the input unit into AC power, and an output unit that outputs the AC power.

Effects of the Invention

[0007] According to the present disclosure, the in-vehicle battery mounted on the working machine is charged.

Brief Description of the Drawings

[0008] [Figure 1]Figure 1 shows a battery management system according to the first embodiment. [Figure 2] Figure 2 shows a power supply device according to the first embodiment. [Figure 3] Figure 3 shows a power supply device according to the second embodiment. [Figure 4] Figure 4 is a flowchart showing the control method for the power supply device according to the second embodiment. [Figure 5] Figure 5 shows a power supply device according to the third embodiment. [Figure 6] Figure 6 is a flowchart showing the control method for the power supply device according to the third embodiment. [Figure 7] Figure 7 is a flowchart showing the control method for the power supply device according to the fourth embodiment. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings, but this disclosure is not limited to these embodiments. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0010] <Management System> Figure 1 shows a management system 1 for a storage battery 2 according to an embodiment. The management system 1 manages the storage battery 2. The storage battery 2 is used to charge the on-board battery 4 mounted on the work machine 3.

[0011] Battery 2 is a rechargeable battery that can be used repeatedly by being recharged. Examples of Battery 2 include lithium-ion batteries and nickel-metal hydride batteries. Battery 2 is a portable battery that can be transported. Battery 2 is transported by a delivery vehicle 5 of a delivery company.

[0012] The work machine 3 operates at the work site 101. The work machine 3 is driven by power output from the onboard battery 4. The work machine 3 is an electric work machine. Examples of work sites 101 include urban road construction sites or indoor demolition sites. Electric work machines do not emit exhaust gases. Electric work machines generate little heat. Electric work machines are very quiet. Therefore, the work machine 3 is suitable for urban road construction or indoor demolition work.

[0013] The on-board battery 4 is a rechargeable battery that can be used repeatedly by being recharged. Examples of the on-board battery 4 include a lithium-ion battery or a nickel-metal hydride battery. The on-board battery 4 is fixed to the work machine 3. The on-board battery 4 functions as the power source for the work machine 3.

[0014] The management system 1 comprises a power supply unit 6, a server 7, and an information terminal 8. The power supply unit 6 is used to charge the vehicle battery 4. The server 7 includes a computer system. In this embodiment, the server 7 includes a first server 7A and a second server 7B. The information terminal 8 is held by the user 100 of the battery 2. Examples of the information terminal 8 include a smartphone, a tablet device, or a personal computer.

[0015] The power supply unit 6 and the first server 7A communicate via a communication system. The first server 7A and the second server 7B communicate via a communication system. The second server 7B and the information terminal 8 communicate via a communication system. Examples of communication systems include the internet, a mobile phone network, a satellite network, or a local area network (LAN).

[0016] The power supply unit 6 is located at the work site 101 of the work machine 3. The server 7 is located in a remote location from the work site 101. The first server 7A is located, for example, at a management facility 102 owned by the work machine manufacturer. The second server 7B is located, for example, at a distribution facility 103 owned by a distribution company that delivers the storage battery 2.

[0017] The storage battery 2 is charged at a remote location from the work site 101. In an embodiment, the storage battery 2 is charged at the distribution facility 103. The charging device 9 of the storage battery 2 is arranged at the distribution facility 103. The storage battery 2 is charged by the charging device 9 at the distribution facility 103. Electric power is supplied from the commercial power supply 10 to the charging device 9. The charging device 9 charges the storage battery 2 based on the electric power supplied from the commercial power supply 10.

[0018] The storage battery 2 charged by the charging device 9 at the distribution facility 103 is delivered to the work site 101 of the work machine 3 by the delivery vehicle 5. The storage battery 2 delivered to the work site 101 is connected to the power supply device 6.

[0019] The power supply device 6 outputs the electric power used for charging the in-vehicle battery 4 in a state where the storage battery 2 is connected.

[0020] The in-vehicle battery 4 is charged at the work site 101. The charging device 11 of the in-vehicle battery 4 is arranged at the work site 101. The in-vehicle battery 4 is charged by the charging device 11 at the work site 101.

[0021] The power supply device 6 outputs electric power to the charging device 11 of the in-vehicle battery 4. Electric power is supplied from the power supply device 6 to the charging device 11. The charging device 11 charges the in-vehicle battery 4 based on the electric power supplied from the power supply device 6.

[0022] The power supply device 6 has an output unit 12 and a communicator 13. The storage battery 2 delivered to the work site 101 by the delivery vehicle 5 is connected to the output unit 12.

[0023] The output unit 12 outputs the electric power used for charging the in-vehicle battery 4 mounted on the work machine 3 in a state where the storage battery 2 is connected.

[0024] The output unit 12 outputs power to the charging device 11 of the on-board battery 4. When connected to the charging device 11, the output unit 12 supplies power to the charging device 11. When the storage battery 2 is connected, the output unit 12 outputs power supplied from the storage battery 2 to the charging device 11. The power output from the storage battery 2 is supplied to the on-board battery 4 via the output unit 12 and the charging device 11.

[0025] Battery 2 is used to charge the vehicle battery 4. The vehicle battery 4 is charged based on the power output from battery 2. As the vehicle battery 4 is charged, the remaining charge of battery 2 decreases. Battery 2, which was used to charge the vehicle battery 4 at the work site 101, is transported to the delivery facility 103 by the delivery vehicle 5. At the delivery facility 103, battery 2 is charged by the charging device 9.

[0026] The communication device 13 transmits battery data Da related to the battery 2 while the battery 2 is connected to the output device 12.

[0027] In this embodiment, the communication device 13 is located on the output device 12. Alternatively, the communication device 13 may be located on the storage battery 2.

[0028] In this embodiment, the battery data Da includes at least one of the usage amount of the battery 2, the remaining capacity of the battery 2, the lifespan of the battery 2, and the location of the battery 2.

[0029] The communication device 13 communicates with the first server 7A. The communication device 13 transmits battery data Da to the first server 7A.

[0030] The first server 7A receives the battery data Da transmitted from the communication device 13. The first server 7A stores the battery data Da. The first server 7A manages the battery data Da.

[0031] The first server 7A communicates with the second server 7B. The first server 7A sends battery data Da to the second server 7B.

[0032] The second server 7B receives the battery data Da transmitted from the first server 7A. Based on the battery data Da, the second server 7B generates required power data Db, which indicates the amount of power required to charge the onboard battery 4.

[0033] The second server 7B provides services to the user 100 of the battery 2. The second server 7B responds to requests from the user 100 of the battery 2.

[0034] The second server 7B generates recommended data Dc related to the delivery of battery 2 based on the required power amount data Db.

[0035] The recommended data Dc includes the recommended number of batteries 2 to be delivered to the power supply unit 6 and the recommended date and time for delivering the batteries 2 to the power supply unit 6.

[0036] The second server 7B communicates with the information terminal 8. The second server 7B sends recommended data Dc to the information terminal 8.

[0037] Information terminal 8 receives recommendation data Dc transmitted from second server 7B. Information terminal 8 has an input device 8A and an output device 8B. Input device 8A generates input data when operated by user 100. A touch panel is exemplified as input device 8A. Input device 8A may also be a computer keyboard or a voice input device. Output device 8B outputs recommendation data Dc. A display device such as a flat panel display is exemplified as output device 8B. Output device 8B may also be a voice output device. User 100 can check the recommendation data Dc via output device 8B of information terminal 8.

[0038] User 100 operates the input device 8A of the information terminal 8 so that the battery 2 charged by the charging device 9 is delivered to the power supply 6, based on the recommended data Dc. Based on the input data obtained by operating the input device 8A, the information terminal 8 generates delivery request data Dd, which requests that the battery 2 charged by the charging device 9 be delivered to the power supply 6. The information terminal 8 sends the delivery request data Dd to the second server 7B.

[0039] The second server 7B receives the delivery request data Dd transmitted from the information terminal 8. Based on the delivery request data Dd, the second server 7B outputs delivery command data De, which instructs the delivery of the battery 2, charged by the charging device 9, to the power supply device 6.

[0040] An output device 14 is connected to the second server 7B. An example of the output device 14 is a display device or an audio output device. The second server 7B outputs delivery command data De to the output device 14. Workers at the delivery facility 103 can check the delivery command data De via the output device 14. Based on the delivery command data De, workers at the delivery facility 103 can arrange for a delivery vehicle 5 to deliver the storage battery 2, which has been charged by the charging device 9, to the power supply device 6 at the work site 101. After the storage battery 2 used to charge the on-board battery 4 at the work site 101 is collected by the driver of the delivery vehicle 5, it is transported to the delivery facility 103 by the delivery vehicle 5.

[0041] The first server 7A acquires battery data Df related to battery 2 located in the distribution facility 103.

[0042] In this embodiment, the battery data Df includes the number of times the battery 2 has been delivered. The battery data Df may also include the required power amount data Db. The battery data Df may include at least one of the usage amount of the battery 2, the remaining capacity of the battery 2, the lifespan of the battery 2, and the location of the battery 2.

[0043] The first server 7A stores the battery data Df. The first server 7A manages the battery data Df. The first server 7A transmits the battery data Df sent to the second server 7B.

[0044] The second server 7B receives the battery data Df transmitted from the first server 7A.

[0045] <Power supply> Figure 2 shows a power supply unit 6 according to an embodiment. In this embodiment, the power supply unit 6 and the charging unit 11 are each located at the work site 101. The charging unit 11 is located at the work site 101 to charge the on-board battery 4 of the work machine 3. The power supply unit 6 is located at the work site 101 to supply power to the charging unit 11. The storage battery 2 is connected to the output 12 of the power supply unit 6. The charging unit 11 is connected to the output 12 of the power supply unit 6. The power supply unit 6 supplies power output from the storage battery 2 to the charging unit 11. By being connected to the output 12 of the power supply unit 6, the charging unit 11 charges the on-board battery 4 based on the power supplied from the storage battery 2.

[0046] The work machine 3 is an electric work machine powered by an on-board battery 4. In this embodiment, the work machine 3 is an electric excavator. The electric excavator has a lower traveling body 3B with tracks 3A, an upper rotating body 3C supported by the lower traveling body 3B, and a work implement 3D supported by the upper rotating body 3C. The electric excavator also has an electric motor, a hydraulic motor, and a hydraulic actuator. The electric motor is driven based on power supplied from the on-board battery 4 mounted on the work machine 3. The hydraulic motor is driven based on the rotational force generated by the electric motor. The hydraulic actuator is driven based on the hydraulic fluid supplied from the hydraulic motor. The lower traveling body 3B, the upper rotating body 3C, and the work implement 3D are each operated by the hydraulic actuator.

[0047] The power supply unit 6 comprises an output unit 12, a communication unit 13, and a control device 15. The output unit 12 has a housing 16, an input unit 17, a power conversion unit 18, and an output unit 19.

[0048] The input section 17 includes an input terminal 20 and an input circuit 21. The power conversion section 18 includes a power conversion circuit 22. The output section 19 includes an output circuit 23 and an output terminal 24.

[0049] The housing 16 accommodates the input circuit 21, the power conversion circuit 22, the output circuit 23, and the control device 15. The input terminal 20 and the output terminal 24 are located on the outer surface of the housing 16. The input terminal 20 and the input circuit 21 are connected by a power line 25. The input circuit 21 and the power conversion circuit 22 are connected by a power line 26. The power conversion circuit 22 and the output circuit 23 are connected by a power line 27. The output circuit 23 and the output terminal 24 are connected by a power line 28.

[0050] DC power is input from the battery 2 to the input unit 17. The battery 2 is connected to and disconnected from the input terminal 20. In this embodiment, the input terminal 20 is connected to the battery 2 via a cable 29. The cable 29 is connected to and disconnected from both the battery 2 and the input terminal 20. The input terminal 20 is connected to the input circuit 21 via a power line 25. With the battery 2 connected to the input terminal 20, DC power is input from the battery 2 to the input circuit 21 via the input terminal 20. The input circuit 21 outputs the DC power input from the battery 2 to the power conversion circuit 22 via a power line 26.

[0051] In this embodiment, a plurality of input terminals 20 are provided. The plurality of input terminals 20 are connected in parallel to the input circuit 21. The storage battery 2 is connected to each of the plurality of input terminals 20. DC power is input to the input circuit 21 from each of the plurality of input terminals 20. The input terminals 20 include at least a first input terminal 20A and a second input terminal 20B.

[0052] The power conversion unit 18 converts the DC power input to the input unit 17 into AC power. The power conversion circuit 22 includes a DC / AC converter. The power conversion circuit 22 converts the DC power output from the input unit 17 into AC power. The power conversion circuit 22 outputs the AC power to the output circuit 23 via the power line 27.

[0053] AC power is input from the power conversion unit 18 to the output unit 19. The output unit 19 outputs the AC power input from the power conversion unit 18 to the outside of the power supply unit 6. The output unit 19 outputs AC power used to charge the onboard battery 4 mounted on the work machine 3. The output unit 19 outputs AC power to the charging device 11 for the onboard battery 4. The output terminal 24 is connected to the output circuit 23 via the power line 28. The output circuit 23 outputs the AC power input from the power conversion circuit 22 to the output terminal 24 via the power line 28.

[0054] The charging device 11 is connected to and detached from the output terminal 24. In this embodiment, the output terminal 24 is connected to the charging device 11 via a cable 30. The output unit 19 outputs AC power input from the power conversion unit 18 to the charging device 11.

[0055] The charging device 11 charges the on-board battery 4 based on the AC power input from the output unit 19. In this embodiment, the charging device 11 is connected to the work machine 3 via a cable 31. A connector 3E is provided on the work machine 3. The cable 31 is connected to and disconnected from the connector 3E. The connector 3E is connected to the on-board battery 4. The power output from the charging device 11 is output to the on-board battery 4 via the cable 31 and the connector 3E. The on-board battery 4 is charged by the power input from the charging device 11.

[0056] The control device 15 includes a computer system. The control device 15 is connected to the input circuit 21, the power conversion circuit 22, and the output circuit 23 via signal line 32A. The control device 15 is also connected to the communication device 13 via signal line 32B.

[0057] The control device 15 acquires battery data Da related to the battery 2 from the input circuit 21 while the input unit 17 and the battery 2 are connected. Because the input circuit 21 and the battery 2 are connected via cable 29, the input circuit 21 can acquire battery data Da from the battery management system (BMS) of the battery 2 via cable 29. As described above, the battery data Da includes at least one of the battery usage, the remaining charge of the battery 2, the lifespan of the battery 2, and the location of the battery 2. The communication device 13 transmits the battery data Da acquired by the control device 15 to the first server 7A while the input unit 17 and the battery 2 are connected.

[0058] The charging device 11 can be connected to a commercial power supply 10. By connecting to the commercial power supply 10, the charging device 11 can charge the onboard battery 4 based on the AC power input from the commercial power supply 10.

[0059] The charging device 11 has a noise filter circuit 33. The noise filter circuit 33 includes either an LC filter and a capacitor, or both. When the charging device 11 charges the on-board battery 4 based on AC power input from the commercial power supply 10, the noise filter circuit 33 is provided in the charging device 11. The AC power input to the charging device 11 from the commercial power supply 10 is output to the on-board battery 4 via the noise filter circuit 33. The noise filter circuit 33 suppresses the generation of noise.

[0060] In this embodiment, the output circuit 23 does not have a noise filter circuit. Only one noise filter circuit is provided in the AC power path between the power line 27, which includes the output circuit 23 and the charging device 11, and the cable 31. Since the charging device 11 is provided with a noise filter circuit 33 and the output circuit 23 is not provided with a noise filter circuit, the occurrence of LC resonance is suppressed. By suppressing the occurrence of LC resonance, the generation of noise is suppressed. In addition, the charging device 11 is prevented from being input with overvoltage or overcurrent.

[0061] <Effects> As described above, according to this embodiment, the charged storage battery 2 is delivered from the distribution facility 103 to the work site 101. At the work site 101, the storage battery 2 is connected to the output 12 of the power supply unit 6, and the output 12 is connected to the charging unit 11. As a result, the power output from the storage battery 2 is input to the on-board battery 4 mounted on the work machine 3 via the power supply unit 6 and the charging unit 11. The on-board battery 4 is efficiently charged by the storage battery 2 at the work site 101 of the work machine 3. The charging unit 11 can charge the on-board battery 4 at the work site 101 of the work machine 3 without using commercial power supply 10. There is no need to install commercial power supply 10 at the work site 101.

[0062] Battery 2 outputs DC power. The DC power output from battery 2 is input to input unit 17 and then converted to AC power by power conversion unit 18. The AC power output from power conversion unit 18 is input to output unit 19. Output unit 19 outputs AC power to the charging device 11 of the onboard battery 4.

[0063] The output unit 19 can output AC power to various charging devices 11. For example, when a first on-board battery 4 is mounted on a first work machine 3 and a second on-board battery 4 is mounted on a second work machine 3, the first charging device 11 may be specially provided to match the characteristics of the first on-board battery 4, and the second charging device 11 may be specially provided to match the characteristics of the second on-board battery 4. The power supply unit 6 can output AC power to both the first and second charging devices 11. The power supply unit 6 can output AC power used to charge the various on-board batteries 4 of the work machine 3. The power supply unit 6 can output AC power to the charging devices 11 used to charge on-board batteries 4 with different characteristics. For example, even if the output voltage of the first on-board battery 4 and the output voltage of the second on-board battery 4 are different, the power supply unit 6 can output AC power to the charging devices 11 used to charge on-board batteries 4 with different characteristics without complicating the power conversion unit 18. The power supply unit 6 can output AC power to the charging device 11 with high versatility.

[0064] The output terminal 24 can be attached to and detached from the charging device 11. This allows the power supply unit 6 to output AC power to various charging devices 11.

[0065] The power supply unit 6 and the charging unit 11 are placed at the work site 101. The storage batteries 2 are delivered from the distribution facility 103 to the work site 101 as needed. The storage batteries 2 are attached to and detached from the power supply unit 6. The appropriate number of storage batteries 2 are delivered from the distribution facility 103 to the work site 101 at the appropriate time. Storage batteries 2 used to charge the on-board battery 4 are transported from the work site 101 to the distribution facility 103. This prevents unnecessary storage batteries 2 from accumulating at the work site 101. For example, even at a work site 101 with limited storage space for storage batteries 2, the on-board battery 4 of the work machine 3 can be charged efficiently.

[0066] The output circuit 23 and the charging device 11 are connected via the power line 28, the output terminal 24, and the cable 30. When the output circuit 23 is connected to the charging device 11 which has a noise filter circuit 33, the output circuit 23 does not have a noise filter circuit, so the occurrence of LC resonance is suppressed. By suppressing the occurrence of LC resonance, the generation of noise is suppressed. In addition, it is suppressed that the charging device 11 is input to an overvoltage or overcurrent.

[0067] Multiple input terminals 20 are provided. These multiple input terminals 20 are connected in parallel to the input circuit 21. By connecting a storage battery 2 to each of the multiple input terminals 20, for example, a large-capacity onboard battery 4 can be charged.

[0068] [Second Embodiment] A second embodiment will now be described. In the following description, components that are the same as or equivalent to those in the above-described embodiment will be denoted by the same reference numerals, and their descriptions will be simplified or omitted.

[0069] Figure 3 shows a power supply unit 62 according to the embodiment. Similar to the embodiment described above, the power supply unit 62 has an input unit 17 including an input terminal 20 and an input circuit 21, a power conversion unit 18 including a power conversion circuit 22, and an output unit 19 including an output circuit 23 and an output terminal 24.

[0070] Multiple input terminals 20 are provided. These multiple input terminals 20 are connected in parallel to the input circuit 21. The storage battery 2 is connected to each of the multiple input terminals 20.

[0071] The input terminal 20 includes at least a first input terminal 20A and a second input terminal 20B. The battery 2 is connected to the first input terminal 20A and the second input terminal 20B, respectively. In the following description, the battery 2 connected to the first input terminal 20A will be appropriately referred to as the first battery 2A, and the battery 2 connected to the second input terminal 20B will be appropriately referred to as the second battery 2B.

[0072] When the first battery 2A is connected to the first input terminal 20A, DC power is input from the first input terminal 20A to the input circuit 21. When the second battery 2B is connected to the second input terminal 20B, DC power is input from the second input terminal 20B to the input circuit 21.

[0073] The input unit 17 includes a switching unit 50 that switches between allowing DC power to be input from the battery 2 to the input circuit 21 and not allowing it to be input when the battery 2 is connected to the input terminal 20. The switching unit 50 is located on the power line 25 between the input terminal 20 and the input circuit 21. When the input terminal 20 and the input circuit 21 are connected by the switching unit 50, DC power is input to the input circuit 21 from the battery 2 connected to the input terminal 20. When the input terminal 20 and the input circuit 21 are disconnected by the switching unit 50, DC power is not input to the input circuit 21 from the battery 2 connected to the input terminal 20.

[0074] In this embodiment, the switching unit 50 includes a first switching unit 50A positioned on the power line 25 between the first input terminal 20A and the input circuit 21, and a second switching unit 50B positioned on the power line 25 between the second input terminal 20B and the input circuit 21. By connecting the first switching unit 50A to the first input terminal 20A and the input circuit 21, DC power is input to the input circuit 21 from the first battery 2A connected to the first input terminal 20A. By connecting the second switching unit 50B to the second input terminal 20B and the input circuit 21, DC power is input to the input circuit 21 from the second battery 2B connected to the second input terminal 20B.

[0075] The control device 15 controls the switching unit 50. The control device 15 outputs a control command to activate the switching unit 50. The control device 15 controls the switching unit 50 to switch between connecting and disconnecting the input terminal 20 and the input circuit 21. The control device 15 controls the switching unit 50 to switch between inputting DC power from the battery 2 connected to the input terminal 20 to the input circuit 21 and not inputting it.

[0076] The control device 15 monitors the remaining charge of the battery 2 connected to the first input terminal 20A and the remaining charge of the battery 2 connected to the second input terminal 20B. When the difference Δr between the remaining charge of the battery 2 connected to the first input terminal 20A and the remaining charge of the battery 2 connected to the second input terminal 20B is greater than or equal to the first threshold SH1, the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from one of the batteries 2, but not from the other battery 2. The first threshold SH1 is a predetermined value and is stored in the control device 15.

[0077] There is a one-to-one correspondence between the remaining charge of battery 2 and the output voltage of battery 2. The more charge remaining in battery 2, the higher the output voltage of battery 2. The less charge remaining in battery 2, the lower the output voltage of battery 2. Of the first battery 2A connected to the first input terminal 20A and the second battery 2B connected to the second input terminal 20B, for example, if the remaining charge of the first battery 2A is high and the remaining charge of the second battery 2B is low, the difference between the output voltage of the first battery 2A and the output voltage of the second battery 2B will be large. When both the first input terminal 20A and the second input terminal 20B are connected to the input circuit 21, a large difference between the output voltage of the first battery 2A and the output voltage of the second battery 2B may cause a short circuit.

[0078] Therefore, the control device 15 monitors the remaining charge of the first battery 2A connected to the first input terminal 20A and the remaining charge of the second battery 2B connected to the second input terminal 20B. Monitoring the remaining charge of the batteries means monitoring the output voltage of the batteries. When the difference Δr between the remaining charge of the first battery 2A connected to the first input terminal 20A and the remaining charge of the second battery 2B connected to the second input terminal 20B is greater than or equal to the first threshold SH1, the control device 15 operates the switching unit 50 so that DC power is input to the input circuit 21 from one of the batteries 2 of the first battery 2A and the second battery 2B, and DC power is not input to the input circuit 21 from the other battery 2 of the first battery 2A and the second battery 2B.

[0079] Figure 4 is a flowchart showing the control method for the power supply device 62 according to the embodiment. The first battery 2A is connected to the first input terminal 20A and the second battery 2B is connected to the second input terminal 20B. The control device 15 controls the first switching unit 50A so that the first input terminal 20A is connected to the input circuit 21, and controls the second switching unit 50B so that the second input terminal 20B is connected to the input circuit 21. The control device 15 monitors the remaining charge of the first battery 2A connected to the first input terminal 20A and the remaining charge of the second battery 2B connected to the second input terminal 20B (step SA1).

[0080] The control device 15 determines whether the difference Δr between the remaining charge of the first battery 2A and the remaining charge of the second battery 2B is greater than or equal to the first threshold SH1 (step SA2).

[0081] In step SA2, if it is determined that the difference Δr is less than the first threshold SH1 (step SA2: No), the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the first battery 2A and the second battery 2B respectively (step SA3).

[0082] In step SA2, if it is determined that the difference Δr is greater than or equal to the first threshold SH1 (step SA2: Yes), the control device 15 determines whether the remaining charge of the first battery 2A is greater than the remaining charge of the second battery 2B (step SA4).

[0083] In step SA4, if it is determined that the remaining charge of the first battery 2A is greater than the remaining charge of the second battery 2B (step SA4: Yes), the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the first battery 2A and not from the second battery 2B (step SA5), as shown in Figure 3.

[0084] In step SA4, if it is determined that the remaining charge of the second battery 2B is greater than the remaining charge of the first battery 2A (step SA4: No), the control device 15 controls the switching unit 50 so that DC power is input from the second battery 2B to the input circuit 21, and DC power is not input from the first battery 2A to the input circuit 21 (step SA6).

[0085] In other words, the control device 15 controls the switching unit 50 so that DC power is input from the first battery 2A to the input circuit 21 and not from the second battery 2B when the difference Δr is greater than or equal to the first threshold SH1 and the remaining charge of the first battery 2A connected to the first input terminal 20A is greater than the remaining charge of the second battery 2B connected to the second input terminal 20B. The control device 15 controls the switching unit 50 so that DC power is input from the second battery 2B to the input circuit 21 and not from the first battery 2A when the difference Δr is greater than or equal to the first threshold SH1 and the remaining charge of the second battery 2B connected to the second input terminal 20B is greater than the remaining charge of the first battery 2A connected to the first input terminal 20A.

[0086] When the difference Δr is greater than or equal to the first threshold SH1, DC power is input to the input circuit 21 from the battery 2 with the greater remaining charge, and DC power is not input to the input circuit 21 from the battery 2 with the less remaining charge, so the difference Δr gradually decreases. The control device 15 controls the switching unit 50 so that when the difference Δr falls below the first threshold SH1, DC power is input to the input circuit 21 from both the first battery 2A and the second battery 2B.

[0087] As described above, according to the embodiment, the control device 15 controls the switching unit 50 so that when the difference Δr between the remaining charge of the battery 2 connected to the first input terminal 20A and the remaining charge of the battery 2 connected to the second input terminal 20B is greater than or equal to the first threshold SH1, DC power is input to the input circuit 21 from one of the batteries 2, but not from the other battery 2. This suppresses the occurrence of short circuits.

[0088] In this embodiment, the control device 15 controls the switching unit 50 such that when the difference Δr is equal to or greater than the first threshold SH1, DC power is input to the input circuit 21 from the battery 2 with the greater remaining charge among the first battery 2A and the second battery 2B, and DC power is not input to the input circuit 21 from the battery 2 with the less remaining charge. Therefore, the remaining charges of the multiple batteries 2 are averaged.

[0089] The control device 15 controls the switching unit 50 so that when the difference Δr falls below the first threshold SH1, DC power is input to the input circuit 21 from both the first battery 2A and the second battery 2B. As a result, DC power is input to the input circuit 21 from each of the multiple batteries 2 while suppressing the occurrence of short circuits.

[0090] In the second embodiment, three or more input terminals 20 may be connected in parallel to the input circuit 21. When the difference Δr between the remaining charge of the battery 2 with the highest remaining charge and the remaining charge of the battery 2 with the lowest remaining charge among the batteries 2 connected to each of the multiple input terminals 20 is greater than or equal to the first threshold SH1, the control device 15 can control the switching unit 50 so that DC power is input to the input circuit 21 from one of the batteries 2 with the highest remaining charge and not from the other battery 2. The control device 15 can also control the switching unit 50 so that DC power is input to the input circuit 21 from the battery 2 with the highest remaining charge and not from the battery 2 with the lowest remaining charge. Furthermore, when the difference Δr falls below the first threshold SH1, the control device 15 can control the switching unit 50 so that DC power is input to the input circuit 21 from each of the multiple batteries 2.

[0091] [Third Embodiment] A third embodiment will now be described. In the following description, components that are the same as or equivalent to those in the embodiments described above will be denoted by the same reference numerals, and their descriptions will be simplified or omitted.

[0092] Figure 5 shows a power supply unit 63 according to the embodiment. Similar to the second embodiment described above, the power supply unit 63 includes an input unit 17 including an input terminal 20 and an input circuit 21, a power conversion unit 18 including a power conversion circuit 22, an output unit 19 including an output circuit 23 and an output terminal 24, and a switching unit 50.

[0093] The input terminal 20 includes at least a first input terminal 20A and a second input terminal 20B. The first input terminal 20A and the second input terminal 20B are connected in parallel to the input circuit 21. A first battery 2A is connected to the first input terminal 20A. A second battery 2B is connected to the second input terminal 20B. The switching unit 50 includes a first switching unit 50A located on the power line 25 between the first input terminal 20A and the input circuit 21, and a second switching unit 50B located on the power line 25 between the second input terminal 20B and the input circuit 21.

[0094] In this embodiment, the power supply unit 63 has a capacitor 51 connected to the switching unit 50. The capacitor 51 is located in the input circuit 21. The capacitor 51 is connected to the switching unit 50 via a power line 25.

[0095] The control device 15 monitors the remaining charge of each of the batteries 2 connected to the plurality of input terminals 20. In one embodiment, the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the battery 2 with the lowest remaining charge among the batteries 2 connected to each of the plurality of input terminals 20, and DC power is not input to the input circuit 21 from the other batteries 2.

[0096] In the example shown in Figure 5, the remaining charge of the first battery 2A is less than the remaining charge of the second battery 2B. The control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the first battery 2A, but not from the second battery 2B.

[0097] Figure 6 is a flowchart showing the control method of the power supply device 63 according to the embodiment. The first battery 2A is connected to the first input terminal 20A and the second battery 2B is connected to the second input terminal 20B. The control device 15 controls the first switching unit 50A so that the first input terminal 20A is connected to the input circuit 21, and controls the second switching unit 50B so that the second input terminal 20B is connected to the input circuit 21. The control device 15 monitors the remaining charge of the first battery 2A connected to the first input terminal 20A and the remaining charge of the second battery 2B connected to the second input terminal 20B (step SB1).

[0098] The control device 15 determines whether the remaining charge of the first battery 2A is less than the remaining charge of the second battery 2B (step SB2).

[0099] In step SB2, if it is determined that the remaining charge of the first battery 2A is less than the remaining charge of the second battery 2B (step SB2: Yes), the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the first battery 2A, but not from the second battery 2B (step SB3), as shown in Figure 5.

[0100] As DC power is input from the first battery 2A to the input circuit 21, the remaining charge of the first battery 2A gradually decreases. The control device 15 determines whether the remaining charge of the first battery 2A has fallen below the second threshold SH2 (step SB4).

[0101] The second threshold SH2 is a predetermined value and is stored in the control device 15. The second threshold SH2 may also be zero.

[0102] In step SB4, if it is determined that the remaining charge of the first battery 2A has fallen below the second threshold SH2 (step SB4: Yes), the control device 15 controls the switching unit 50 so that DC power is input from the second battery 2B to the input circuit 21 (step SB5).

[0103] If, in step SB4, it is determined that the remaining charge of the first battery 2A is not below the second threshold SH2 (step SB4: No), the processing in step SB3 and step SB4 is repeated until it is determined that the remaining charge of the first battery 2A is below the second threshold SH2.

[0104] In step SB2, if it is determined that the remaining charge of the second battery 2B is less than the remaining charge of the first battery 2A (step SB2: No), the control device 15 controls the switching unit 50 so that DC power is input from the second battery 2B to the input circuit 21, and DC power is not input from the first battery 2A to the input circuit 21 (step SB6).

[0105] As DC power is input from the second battery 2B to the input circuit 21, the remaining charge of the second battery 2B gradually decreases. The control device 15 determines whether the remaining charge of the second battery 2B has fallen below the second threshold SH2 (step SB7).

[0106] In step SB7, if it is determined that the remaining charge of the second battery 2B has fallen below the second threshold SH2 (step SB7: Yes), the control device 15 controls the switching unit 50 so that DC power is input from the first battery 2A to the input circuit 21 (step SB8).

[0107] If, in step SB7, it is determined that the remaining charge of the second battery 2B is not below the second threshold SH2 (step SB7: No), the processing in step SB6 and step SB7 is repeated until it is determined that the remaining charge of the second battery 2B is below the second threshold SH2.

[0108] As described above, according to the embodiment, the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the battery 2 with the lowest remaining charge among the first battery 2A and the second battery 2B, and DC power is not supplied to the input circuit 21 from the battery 2 with the highest remaining charge. In other words, the control device 15 preferentially uses the battery 2 with the lowest remaining charge among the multiple batteries 2. As a result, the control device 15 can use up the battery 2 with the lowest remaining charge in a short time. The used-up battery 2 is transported from the work site 101 to the distribution facility 103, thereby preventing the used-up battery 2 from accumulating at the work site 101.

[0109] In this embodiment, the control device 15 controls the switching unit 50 so that, for example, after the remaining charge of the first battery 2A falls below the second threshold SH2, DC power is input to the input circuit 21 from the second battery 2B, which has the next lowest remaining charge after the first battery 2A. That is, when the remaining charge of the first battery 2A is depleted, the control device 15 switches from inputting DC power from the first battery 2A to the input of DC power from the second battery 2B to the input circuit 21. As a result, DC power is continuously input to the input circuit 21.

[0110] In this embodiment, a capacitor 51 is connected to the switching unit 50. Therefore, when switching from the input of DC power from the first battery 2A to the input of DC power from the second battery 2B to the input of DC power to the input circuit 21, the power stored in the capacitor 51 prevents a period during which DC power is not input to the input circuit 21.

[0111] In the third embodiment, three or more input terminals 20 may be connected in parallel to the input circuit 21. With a battery 2 connected to each of the three or more input terminals 20, the control device 15 can control the switching unit 50 so that DC power is input to the input circuit 21 from the first battery 2 with the lowest remaining charge among the batteries 2 connected to each of the multiple input terminals 20, and DC power is not input to the input circuit 21 from the other batteries 2. Furthermore, after the remaining charge of the first battery 2 falls below the second threshold SH2, the control device 15 can control the switching unit 50 so that DC power is input to the input circuit 21 from the second battery 2 with the next lowest remaining charge after the first battery 2, and DC power is not input to the input circuit 21 from the other batteries 2.

[0112] In addition, a capacitor 51 may be connected to the switching unit 50 of the power supply device 62 described in the second embodiment above.

[0113] [Fourth Embodiment] A fourth embodiment will now be described. In the following description, components that are the same as or equivalent to those in the embodiments described above will be denoted by the same reference numerals, and their descriptions will be simplified or omitted.

[0114] In the third embodiment described above, the battery 2 with the lowest remaining charge among the multiple batteries 2 is used preferentially. In the fourth embodiment, an example will be described in which the battery 2 with the highest remaining charge among the multiple batteries 2 is used preferentially.

[0115] Figure 7 is a flowchart showing the control method for the power supply unit 63 according to the embodiment. Note that the capacitor 51 may be omitted in the power supply unit 63.

[0116] The control device 15 monitors the remaining charge of the first battery 2A connected to the first input terminal 20A and the remaining charge of the second battery 2B connected to the second input terminal 20B (step SC1).

[0117] The control device 15 determines whether the remaining charge of the first battery 2A is greater than the remaining charge of the second battery 2B (step SC2).

[0118] In step SC2, if it is determined that the remaining charge of the first battery 2A is greater than the remaining charge of the second battery 2B (step SC2: Yes), the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the first battery 2A and not from the second battery 2B (step SC3).

[0119] As DC power is input from the first battery 2A to the input circuit 21, the remaining charge of the first battery 2A gradually decreases. The control device 15 determines whether the difference Δr between the remaining charge of the first battery 2A and the remaining charge of the second battery 2B has fallen below the third threshold SH3 (step SC4).

[0120] The third threshold SH3 is a predetermined value and is stored in the control device 15. The third threshold SH3 may also be zero.

[0121] In step SC4, if it is determined that the difference Δr is less than or equal to the third threshold SH3 (step SC4: Yes), the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the first battery 2A and the second battery 2B, respectively (step SC5).

[0122] If, in step SC4, it is determined that the difference Δr is not less than or equal to the third threshold SH3 (step SC4: No), the processes in step SC3 and step SC4 are repeated until it is determined that the difference Δr is less than or equal to the third threshold SH3.

[0123] In step SC2, if it is determined that the remaining charge of the second battery 2B is greater than the remaining charge of the first battery 2A (step SC2: No), the control device 15 controls the switching unit 50 so that DC power is input from the second battery 2B to the input circuit 21, and DC power is not input from the first battery 2A to the input circuit 21 (step SC6).

[0124] As DC power is input from the second battery 2B to the input circuit 21, the remaining charge of the second battery 2B gradually decreases. The control device 15 determines whether the difference Δr between the remaining charge of the first battery 2A and the remaining charge of the second battery 2B has fallen below the third threshold SH3 (step SC7).

[0125] In step SC7, if it is determined that the difference Δr is less than or equal to the third threshold SH3 (step SC7: Yes), the control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from the first battery 2A and the second battery 2B, respectively (step SC5).

[0126] If, in step SC7, it is determined that the difference Δr is not less than or equal to the third threshold SH3 (step SC7: No), the processes in step SC6 and step SC7 are repeated until it is determined that the difference Δr is less than or equal to the third threshold SH3.

[0127] As described above, in this embodiment, the control device 15 controls the switching unit 50 so that when the remaining charge of the first battery 2A connected to the first input terminal 20A is greater than the remaining charge of the second battery 2B connected to the second input terminal 20B, DC power is input from the first battery 2A to the input circuit 21, and DC power is not input from the second battery 2B to the input circuit 21. This reduces the difference Δr between the remaining charge of the first battery 2A and the remaining charge of the second battery 2B. As mentioned above, a large difference Δr can cause a short circuit. According to this embodiment, since the difference Δr is reduced, the occurrence of a short circuit is suppressed.

[0128] The control device 15 controls the switching unit 50 so that DC power is input to the input circuit 21 from both the first battery 2A and the second battery 2B when the difference Δr between the remaining charge of the first battery 2A and the remaining charge of the second battery 2B falls below the third threshold SH3. The control device 15 may also control the switching unit 50 so that DC power is input to the input circuit 21 from both the first battery 2A and the second battery 2B when the remaining charge of the first battery 2A and the remaining charge of the second battery 2B become equal. As a result, DC power is input to the input circuit 21 from each of the multiple batteries 2 while suppressing the occurrence of short circuits. By inputting DC power to the input circuit 21 from each of the multiple batteries 2, the amount of DC power input to the input circuit 21 from a single battery 2 is reduced. This suppresses a shortening of the battery life 2.

[0129] In the fourth embodiment as well, three or more input terminals 20 may be connected in parallel to the input circuit 21.

[0130] [Other embodiments] In the above-described embodiment, the work machine 3 is assumed to be an electric shovel. The work machine 3 may also be an electric forklift. An electric forklift has wheels, a body supported by the wheels, a mast supported by the body, and forks supported by the mast. An electric forklift also has an electric motor, a hydraulic motor, and a hydraulic actuator. The electric motor is driven based on power supplied from an on-board battery 4 mounted on the work machine 3. The hydraulic motor is driven based on the rotational force generated by the electric motor. The hydraulic actuator is driven based on the hydraulic fluid supplied from the hydraulic motor. The wheels, mast, and forks are each actuated by the hydraulic actuator.

[0131] In the above-described embodiment, the work machine 3 does not necessarily have a work implement. The work machine 3 may be, for example, an electric dump truck, which is a type of electric transport vehicle. [Explanation of Symbols]

[0132] 1...Management system, 2...Battery, 2A...First battery, 2B...Second battery, 3...Work machine, 3A...Track, 3B...Lower running body, 3C...Upper rotating body, 3D...Work machine, 3E...Connector, 4...On-board battery, 5...Delivery vehicle, 6...Power supply unit, 7...Server, 7A...First server, 7B...Second server, 8...Information terminal, 8A...Input device, 8B...Output device, 9...Charging device, 10...Commercial power supply, 11...Charging device, 12...Output unit, 13...Communication device, 14...Output device, 15...Control device, 16...Housing, 17...Input unit, 18...Power conversion unit, 19...Output unit, 20...Input terminal, 20A...First input terminal, 20B...Second input terminal, 2 1...Input circuit, 22...Power conversion circuit, 23...Output circuit, 24...Output terminal, 25...Power line, 26...Power line, 27...Power line, 28...Power line, 29...Cable, 30...Cable, 31...Cable, 32A...Signal line, 32B...Signal line, 33...Noise filter circuit, 50...Switching unit, 50A...First switching unit, 50B...Second switching unit, 51...Capacitor, 62...Power supply unit, 63...Power supply unit, 100...User, 101...Work site, 102...Management facility, 103...Delivery facility, Da...Battery data, Db...Required power amount data, Dc...Recommended data, Dd...Delivery request data, De...Delivery instruction data, Df...Battery data.

Claims

1. An input unit to which DC power is input from a storage battery charged at a remote location at the work site of a work machine, A power conversion unit that converts the DC power input to the input unit into AC power, With the storage battery connected to the input unit, the system includes an output unit that outputs AC power to a charging device installed at the work site for charging an on-board battery mounted on a work machine, power supply.

2. The output unit includes an output circuit to which AC power is input from the power conversion unit, and an output terminal connected to the output circuit to which the charging device is attached and detached. The power supply device according to claim 1.

3. The charging device has a noise filter circuit, The output circuit does not have a noise filter circuit. The power supply device according to claim 2.

4. The input section includes an input terminal into which the battery is attached and detached, and an input circuit into which DC power is input from the battery when the battery is connected to the input terminal. A power supply device according to any one of claims 1 to 3.

5. Multiple input terminals are provided, Multiple of the aforementioned input terminals are connected in parallel to the input circuit. The power supply device according to claim 4.

6. The input unit includes a switching unit that switches between inputting DC power from the battery to the input circuit and not inputting DC power when the battery is connected to the input terminal. The power supply device according to claim 5.

7. The device includes a control unit that controls the switching section so that when the difference between the remaining charge of the battery with the highest remaining charge and the remaining charge of the battery with the lowest remaining charge among the batteries connected to each of the multiple input terminals is greater than or equal to a first threshold, DC power is input to the input circuit from one battery and DC power is not input to the input circuit from the other battery. The power supply device according to claim 6.

8. The control device controls the switching unit so that DC power is input to the input circuit from the battery with the highest remaining charge, and DC power is not input to the input circuit from the battery with the lowest remaining charge. The power supply device according to claim 7.

9. The control device controls the switching unit so that when the difference falls below a first threshold, DC power is input to the input circuit from each of the multiple storage batteries. The power supply device according to claim 8.

10. The device includes a control device that controls the switching section so that DC power is input to the input circuit from the first battery with the lowest remaining charge among the batteries connected to each of the multiple input terminals, and DC power is not input to the input circuit from the other batteries. The power supply device according to claim 6.

11. The control device controls the switching unit so that, after the remaining charge of the first battery falls below the second threshold, DC power is input to the input circuit from the second battery, which has the next lowest remaining charge after the first battery, and DC power is not input to the input circuit from the other batteries. The power supply device according to claim 10.

12. The switching section includes a capacitor connected to it. A power supply device according to any one of claims 8 to 11.

13. When the remaining charge of the first battery connected to the first input terminal is greater than the remaining charge of the second battery connected to the second input terminal, the switching unit is controlled so that DC power is input from the first battery to the input circuit and DC power is not input from the second battery to the input circuit. The device includes a control device that controls the switching unit so that when the difference between the remaining charge of the first battery and the remaining charge of the second battery falls below a third threshold, DC power is input to the input circuit from both the first battery and the second battery. The power supply device according to claim 6.

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