Electric work machine

Abstract

An electric work machine driven by an electric motor includes a battery for supplying electric power to the electric motor, and a first power supply port and a second power supply port to which is connected a power supply cable for supplying electric power from an external power source to the battery. When the power supply cable is connected to the first power supply port, driving by the electric motor is permitted, and when the power supply cable is connected to the second power supply port, driving by the electric motor is prohibited.

Description

Electric working machine

[0001] The present invention relates to an electric working machine.

[0002] In an electric hydraulic excavator which is a kind of electric working machine, a battery is mounted as one of the energy sources, and when charging the battery, a charging cable is connected and charging is performed by an external power source. At this time, Patent Document 1 is known as a technique for preventing the hydraulic excavator from operating while the cable is connected. In the electric hydraulic excavator described in Patent Document 1, in a configuration including a charging port to which a charging cable for supplying DC power is connected and a charging port to which a charging cable for supplying AC power is connected, when a charging cable is connected to any of the charging ports, the operation of the electric hydraulic excavator is stopped.

[0003] International Publication No. 2022 / 210391

[0004] By the way, since charging takes a long time, in a situation where the cable arrangement can be fully recognized, there are many demands to operate the electric hydraulic excavator while charging. However, in the technique of Patent Document 1, the operation of the electric hydraulic excavator is forcibly stopped during charging, so work cannot be performed, and there is a problem that an increase in the downtime of the electric hydraulic excavator cannot be avoided. In particular, in an electric hydraulic excavator, an operation may be taken to perform charging such as rapid charging during breaks in work to secure the operating time after resuming work. In this case, in a configuration that allows the operation of the electric hydraulic excavator during charging, there is a possibility that a third party other than the operator who connected the cable may board the electric hydraulic excavator and resume work without knowing that the cable is connected to the electric hydraulic excavator.

[0005] An object of the present invention is to provide a technique capable of preventing the start of work of an electric working machine by a third party while allowing the operation of the electric working machine during charging.

[0006] An electric work machine according to an aspect of the present invention is an electric work machine driven by an electric motor, comprising a battery that supplies power to the electric motor, and a first power supply port and a second power supply port to which a power supply cable for supplying power from an external power source to the battery is connected, characterized in that when the power supply cable is connected to the first power supply port, driving by the electric motor is permitted, and when the power supply cable is connected to the second power supply port, driving by the electric motor is prohibited.

[0007] According to the present invention, it is possible to allow the operation of an electric work machine while it is being charged, thereby reducing downtime during which work cannot be performed, while preventing a third party from starting work on the electric work machine.

[0008] Figure 1 shows the external appearance of a hydraulic excavator. Figure 2 is a block diagram of the hydraulic excavator's system. Figure 3 is a flowchart illustrating the startup sequence of the hydraulic excavator. Figure 4 shows the relationship between the operating mode and the determination conditions. Figure 5 is a functional block diagram illustrating the function of the vehicle controller in battery-powered mode. Figure 6 is a functional block diagram illustrating the function of the vehicle controller in AC charging mode. Figure 7 is a functional block diagram illustrating the function of the vehicle controller in rapid charging mode. Figure 8 is a functional block diagram illustrating the function of the vehicle controller in AC power supply assist mode. Figure 9 is a diagram illustrating the startup process of rapid charging mode in a modified example.

[0009] Embodiments of the electric work machine according to the present invention will be described below with reference to the drawings. The following description and drawings are illustrative examples for explaining the present invention, and have been omitted and simplified as appropriate for clarity of explanation. In addition, in the following description, the same or similar elements and processes are denoted by the same reference numerals, and redundant explanations may be omitted. It should be noted that the contents described below are merely examples of embodiments of the present invention, and the present invention is not limited to the embodiments described below, and can be implemented in various other forms.

[0010] Hereinafter, an electric hydraulic excavator will be used as an example of an electric work machine according to the embodiment of the present invention, but the present invention can be applied to various electric work machines, not limited to electric hydraulic excavators. Figure 1 is a diagram showing the external appearance of the hydraulic excavator 1. Figure 2 is a block diagram showing the system of the hydraulic excavator 1.

[0011] As shown in Figure 2, the hydraulic excavator 1 is an electric hydraulic excavator that drives the hydraulic pump 8 and pilot pump 14 with an electric motor 7 powered by the battery 10. The hydraulic excavator 1 operates each hydraulic actuator (bucket cylinder 2, arm cylinder 3, boom cylinder 4, slewing motor 5, travel motor 6) by distributing and controlling the pressurized oil produced by the hydraulic pump 8 with a control valve unit 9, thereby performing excavation, slewing, and travel operations.

[0012] When the travel motor 6, located on the lower travel body 100 as shown in Figure 1, rotates using pressurized oil, the crawler 101 is driven and the lower travel body 100 moves. The upper slewing body 200, mounted on the lower travel body 100 via a slewing device 110, slewing relative to the lower travel body 100 when the slewing motor 5 is rotated. The front working device 300, located at the front of the upper slewing body 200, includes a boom 301 driven by a boom cylinder 4, an arm 302 driven by an arm cylinder 3, and a bucket 303 driven by a bucket cylinder 2. Inside the cab 201 located on the upper slewing body 200, there are operating levers 11, lock levers 12, etc., which will be described later.

[0013] As shown in Figure 2, the control valve unit 9 is driven by operating the operating lever 11 inside the cab 201 to distribute the pressurized oil produced by the pilot pump 14 to the control valve unit 9. The supply of pressurized oil from the pilot pump 14 to the control valve unit 9 is opened and closed by the lock valve 13. The lock valve 13 can be controlled by the lock lever 12 inside the cab 201. The lock valve 13 is composed of a solenoid valve, which is closed when OFF and open when ON.

[0014] Here, a lock valve authorization relay 15 is interposed between the solenoid valve constituting the lock valve 13 and the circuit of the lock lever 12. The lock valve authorization relay 15 is a relay that is open when there is no power supply. Therefore, the lock valve 13 can only be turned ON / OFF by the lock lever 12 when the lock valve authorization relay 15 is closed (when there is power supply). In other words, if there is no power supply to the lock valve authorization relay 15 and it is open, the lock valve 13 will remain closed at all times. The hydraulic excavator 1 also has a vehicle controller 16 that monitors and controls the state of the vehicle body and communicates with each piece of equipment, and monitors and controls the state of the hydraulic excavator 1 and the state of each piece of equipment mounted on it.

[0015] The DC power from the battery 10 is converted into three-phase AC power by the inverter 17, and this three-phase AC power is supplied to the electric motor 7. The operation of the electric motor 7 is controlled by controlling the three-phase AC power with the inverter 17.

[0016] The hydraulic excavator 1 is equipped with an AC power port 19. An AC power cable 181 from an external power source 18 can be connected to the AC power port 19. The AC power supplied from the AC power port 19 is converted to DC power by an onboard charger (OBC) 20. The onboard charger 20 has a current control charging function and a voltage control charging function, and charges the battery 10 using these charging functions. Near the AC power port 19, there is an AC charging button 21 connected to the vehicle controller 16. The operator can start and stop AC charging by operating this AC charging button 21.

[0017] An AC power cable 181 connected to the AC power outlet 19 has one end of a wire fixed about 1 meter from the AC power plug, and the other end of the wire is connected to a locking mechanism of the AC power plug (not shown). Therefore, if the AC power cable 181 is pulled and the tension of the wire exceeds a certain level, the AC power plug will be removed from the AC power outlet 19.

[0018] Furthermore, the hydraulic excavator 1 is equipped with a rapid power supply port 23. A DC power supply cable 221 from an external charger 22 can be connected to the rapid power supply port 23. By connecting the DC power supply cable 221 to the rapid power supply port 23, the battery 10 is charged by DC power supplied by the external charger 22. Charging by the external charger 22 is controlled by an external charger control controller 24 provided on the external charger 22.

[0019] The external charger 22 is equipped with a touch panel control panel 25. The operator can start and stop charging by operating the control panel 25. During charging, the vehicle controller 16 and the external charger control controller 24 communicate via the rapid charging port 23 using communication based on the CCS (Combined Charging System) standard, which is the rapid charging standard for electric vehicles, and share upper limits for voltage and current, as well as the timing of starting and stopping charging.

[0020] The battery 10, the rapid power supply port 23, the on-board charger 20, and the inverter 17 are connected by a high-voltage power circuit 26. The battery 10 is equipped with a BMU (Battery Management Unit) 27 that monitors the battery 10 itself. The BMU 27 is connected to the vehicle controller 16 via a CAN communication network 28 and shares the monitoring results with the vehicle controller 16.

[0021] The inverter 17 is equipped with an inverter controller 29 that controls the inverter circuit that generates three-phase AC power. The inverter controller 29 is connected to the vehicle controller 16 via a CAN communication network 28 and communicates with the vehicle controller 16 via CAN. The onboard charger 20 includes a converter circuit (not shown) that controls the voltage and current of the power supplied to the battery 10, and a converter controller 30 that controls the converter circuit. The converter controller 30 is connected to the vehicle controller 16 via a CAN communication network 28 and communicates with the vehicle controller 16 via CAN.

[0022] Furthermore, the vehicle controller 16, the BMU 27, and each controller 30, 29 are connected by an electrical signal line that transmits start signals. The vehicle controller 16 transmits a battery start signal 31, an onboard charger start signal 32, and an inverter start signal 33 to the BMU 27 and each controller 30, 29. Each start signal is a High / Low signal; supplying High instructs the target device to start, and supplying Low instructs the target device to stop.

[0023] The rapid power supply port 23 has a terminal for the control pilot (CP) signal, which is connected to the vehicle controller 16 via a CP communication line 34. When the connection plug 222 of the DC power supply cable 221 is connected to the rapid power supply port 23, the CP signal is supplied to the vehicle controller 16. As a result, the vehicle controller 16 detects the insertion of the connection plug 222 into the rapid power supply port 23.

[0024] An AC junction box 35, which has a relay driven by AC power, is provided between the AC power supply port 19 and the on-board charger 20. By transmitting an electrical signal 35a indicating the operation of this relay to the vehicle controller 16, the vehicle controller 16 can detect that the connection plug of the AC power supply cable 181 has been inserted into the AC power supply port 19. When at least one of the following signals is generated—a key-on signal emitted by turning the key cylinder 36 to the ON position, an insertion detection signal for the rapid power supply port 23, and an insertion detection signal for the AC power supply port 19—the vehicle controller 16 generates a start signal, and the hydraulic excavator 1 starts up.

[0025] The cab 201 shown in Figure 1 is equipped with a key cylinder 36 for starting the hydraulic excavator 1. By setting the key cylinder 36 to the ON position, the hydraulic excavator 1 can be started. Furthermore, by moving the key cylinder 36 to the START position and then back to the ON position, the electric motor 7 can be started. The signal from the key cylinder 36 is monitored by the digital input of the vehicle controller 16, which enables the above operations.

[0026] A pump control dial 37 is provided inside the cab 201, and the pump control dial 37 is connected to the vehicle controller 16. The state of the pump control dial 37 indicates the rotation speed of the hydraulic pump 8, and the vehicle controller 16 changes the rotation speed instruction to the inverter 17 according to this state.

[0027] Figure 3 is a flowchart illustrating the startup sequence of the hydraulic excavator 1. As described above, the hydraulic excavator 1 starts up by performing at least one of the following: turning the key cylinder 36 to the ON position, connecting the connection plug 222 to the rapid power supply port 23, and connecting the connection plug to the AC power supply port 19. When the hydraulic excavator 1 starts up, the vehicle controller 16 starts up and begins the startup sequence shown in Figure 3.

[0028] In step S0, the vehicle controller 16 determines the operating mode of the hydraulic excavator 1. The vehicle controller 16 monitors the key-on signal emitted by turning the key cylinder 36 to the ON position via digital input, and after startup, determines the operating mode as shown in Figure 4 based on the state of the key cylinder 36, the plug insertion state of the AC power supply port 19, and the plug insertion state of the rapid power supply port 23.

[0029] Figure 4 shows the relationship between the operating mode and the judgment conditions. There are four types of operating modes: "battery powered mode," "AC charging mode," "rapid charging mode," and "AC power supply assist mode." The judgment conditions (input conditions) are the ON signal of the key cylinder 36 (key-on signal), the insertion detection result of the AC power supply port 19 (insertion detection signal), and the insertion detection result of the rapid power supply port 23 (insertion detection signal).

[0030] The "battery-powered mode" is an operating mode in which only the battery 10 is used as the power source for the electric motor 7, and excavation, slewing, and travel operations are permitted by operating the control lever 11. The input conditions for determining the operating mode are that there is a key-on signal input from the key cylinder 36, and there is no insertion detection signal input from the AC power supply port 19 and the rapid power supply port 23. In such cases, the operating mode of the hydraulic excavator 1 transitions to "battery-powered mode".

[0031] The "AC charging mode" is an operating mode in which the battery 10 is charged by normal charging using the onboard charger 20. The input conditions are that there is no key-on signal input from the key cylinder 36, there is an insertion detection signal input from the AC power supply port 19, and there is no insertion detection signal input from the rapid power supply port 23. In this case, the operating mode of the hydraulic excavator 1 transitions to "AC charging mode".

[0032] The "AC Power Supply Assist Mode" is an operating mode in which the electric motor 7 is driven while power is supplied from the onboard charger 20 to the battery 10 and inverter 17, and excavation, turning, and driving operations can be performed by operating the control lever 11. The "AC Power Supply Assist Mode" is an operating mode that is entered when there is a key-on signal input from the key cylinder 36, an insertion detection signal input from the AC power supply port 19, and no insertion detection signal input from the rapid power supply port 23.

[0033] If the power consumption of the electric motor 7 exceeds the power supplied by the onboard charger 20, the battery 10 is discharged, and power is supplied to the electric motor 7 from the battery 10. On the other hand, if the power consumption of the electric motor 7 is less than the power supplied by the onboard charger 20, the battery 10 is charged by a portion of the power supplied by the onboard charger 20.

[0034] The "rapid charging mode" is an operating mode in which the battery 10 is charged by DC power supplied by the external charger 22. The "rapid charging mode" is an operating mode that is entered when there is an insertion detection signal from the rapid charging port 23, regardless of whether there is an input of a key-on signal from the key cylinder 36 or an insertion detection signal from the AC power port 19.

[0035] Returning to Figure 3, if the operating mode is determined in step S0, the startup process for the equipment necessary for the operation of the determined operating mode is performed. If "battery powered mode" is determined in step S0, the startup processes from steps S11 to S15 are executed. If "AC charging mode" is determined, the startup processes from steps S21 to S24 are executed. If "rapid charging mode" is determined, the startup processes from steps S31 to S34 are executed. If "AC power supply assist mode" is determined, the startup processes from steps S41 to S47 are executed.

[0036] <Startup process for "battery-powered mode"> In step S11, the vehicle controller 16 sets the battery start signal 31 to High (start instruction) and waits for the battery 10 to start up. When the battery 10 starts up, the BMU 27, which monitors the battery 10, performs a diagnosis of any abnormalities in the battery 10. If the diagnosis result is normal, the BMU 27 precharges the high-voltage power circuit 26, closes the internal contactor (not shown), and then transmits a start-up completion signal via CAN communication. When the vehicle controller 16 receives this start-up completion signal, in step S12, the vehicle controller 16 determines that the battery 10 has finished starting up.

[0037] In step S13, the vehicle controller 16 sets the inverter start signal 33 high and waits for the inverter 17 to start. When the inverter start signal 33 goes high, the inverter 17 starts up, starts the electric motor 7, and performs a diagnostic check for abnormalities in the inverter 17 and the electric motor 7. If the diagnostic result is normal, the inverter 17 sends a startup completion signal to the vehicle controller 16 via CAN communication.

[0038] When the vehicle controller 16 receives a startup completion signal from the inverter 17, in step S14, the vehicle controller 16 determines that the inverter 17 and the electric motor 7 have finished starting up. Next, in step S15, the vehicle controller 16 closes the lock valve permission relay 15 to connect the lock lever 12 and the lock valve 13, and the startup process is completed. From this point onward, the system awaits operator input.

[0039] <Starting up "AC charging mode"> The processes in steps S21 and S22 in AC charging mode are the same as the processes in steps S11 and S12 described above. That is, in step S21, the vehicle controller 16 sets the battery start signal 31 to High, and in step S22, the vehicle controller 16 determines that the battery 10 has finished starting up.

[0040] In step S23, the vehicle controller 16 sets the onboard charger start signal 32 to High and waits for the onboard charger 20 to start up. When the onboard charger 20 starts up, it performs a self-diagnosis and, if normal, sends a start-up completion signal to the vehicle controller 16 via CAN communication. When the vehicle controller 16 receives the start-up completion signal from the onboard charger 20, in step S24, the vehicle controller 16 determines that the onboard charger 20 has finished starting up. With this, the start-up process is complete, and from here on, the system waits for operator input.

[0041] <Starting up "Rapid Charging Mode"> The processes in steps S31 and S32 in rapid charging mode are the same as the processes in steps S11 and S12 described above. That is, in step S31, the vehicle controller 16 sets the battery start signal 31 to High, and in step S32, the vehicle controller 16 determines that the battery 10 has finished starting up.

[0042] In step S33, the vehicle controller 16 initiates communication with the external charger 22 via the CP communication line 34. The external charger 22 returns a response to the vehicle controller 16 via the CP communication line 34. As described above, when the connection plug 222 of the DC power supply cable 221 is connected to the rapid power supply port 23, a CP signal is sent to the vehicle controller 16. Upon receiving the response from the external charger 22, the vehicle controller 16 determines in step S34 that the external charger 22 has finished starting up. With this, the startup process is complete, and from here on, the system awaits operator input.

[0043] <Startup Process of "AC Power Supply Assist Mode"> The processes of steps S41 and S42 in the AC power supply assist mode are the same as the processes of steps S11 and S12 described above. That is, in step S41, the vehicle body controller 16 sets the battery startup signal 31 to High, and in step S42, the vehicle body controller 16 determines the completion of the startup of the battery 10.

[0044] The processes of subsequent steps S43 and S44 are the same as the processes of steps S23 and S24 described above. That is, in step S43, the vehicle body controller 16 sets the in-vehicle charger startup signal 32 to High and waits for the startup of the in-vehicle charger 20. When the vehicle body controller 16 receives the startup completion signal from the in-vehicle charger 20, in step S44, the vehicle body controller 16 determines that the in-vehicle charger 20 has completed startup.

[0045] Further, the processes from step S45 to step S47 are the same as the processes from step S13 to step S15 described above. That is, in step S45, the vehicle body controller 16 sets the inverter startup signal 33 to High and waits for the startup of the inverter 17. When the vehicle body controller 16 receives the startup completion signal from the inverter 17, in step S46, the vehicle body controller 16 determines that the inverter 17 and the electric motor 7 have completed startup. In step S47, the vehicle body controller 16 closes the lock valve permission relay 15 to connect the lock lever 12 and the lock valve 13, and the startup process is completed. After this, it waits for the operator's operation.

[0046] In the battery drive mode and the AC power supply assist mode, since the inverter startup process (steps S13, S45) and the connection process of the lock valve permission relay 15 (steps S15, S47) are executed, the hydraulic excavator 1 can perform excavation operations, turning operations, and traveling operations. On the other hand, in the AC charging mode and the rapid charging mode, since the inverter startup process and the connection process of the lock valve permission relay 15 are not executed, the excavation operation, turning operation, and traveling operation are in a prohibited state.

[0047] Next, referring to FIGS. 5 to 8, the functions of the vehicle body controller 16 related to the operation of the hydraulic excavator 1 in each operation mode will be described. FIG. 5 is a functional block diagram for explaining the functions of the vehicle body controller 16 in the battery drive mode. In the battery drive mode, the vehicle body controller 16 receives the START signal 36S of the key cylinder 36 and the input of the dial operation amount signal 37S of the pump control dial 37. The START signal 36S is a signal generated when the key cylinder 36 is moved from the ON position to the START position. The START signal 36S is input to the key start detection unit 161 of the vehicle body controller 16, and the dial operation amount signal 37S is input to the rotation speed command generation unit 160.

[0048] The rotation speed command generation unit 160 generates a rotation speed command 160S based on the dial operation amount signal 37S of the pump control dial 37. For example, when the dial is in the Low position, the indication is 1000 rpm, when in the High position, the indication is 1800 rpm, and the rotation speed indication changes linearly therebetween. The rotation speed command 160S is input to the key start detection unit 161.

[0049] When the vehicle body controller 16 is activated, the key start detection unit 161 waits for the input of the START signal 36S. While there is no input of the START signal 36S, a value of 0 is output as the rotation speed command 161S regardless of the output content of the rotation speed command generation unit 160. On the other hand, after the input of the START signal 36S, the rotation speed command 160S input from the rotation speed command generation unit 160 is output as the rotation speed command 161S as it is. The rotation speed command 161S output from the key start detection unit 161 is transmitted to the inverter 17 by CAN communication.

[0050] The inverter 17 controls the rotation speed of the electric motor 7 based on the received rotation speed command 161S. This drives the hydraulic pump 8 and the pilot pump 14, supplying pressurized oil to the control valve unit 9 and the lock valve 13. In this state, when the operator releases the lock lever 12, the lock valve permission relay 15 is connected as described above, so the lock valve 13 opens and pressurized oil is supplied to the operating lever 11. Therefore, when the operator operates the operating lever 11, the control valve unit 9 is activated, allowing the hydraulic excavator 1 to perform digging, slewing, and traveling operations. The operations based on the operation of the lock lever 12 and the operating lever 11 are performed by the electrical and hydraulic circuits without going through the software of the vehicle controller 16.

[0051] Figure 6 is a functional block diagram illustrating the functions of the vehicle controller 16 in AC charging mode. In AC charging mode, the vehicle controller 16 receives the signal 21S from the AC charging button 21 at the charging state determination unit 163.

[0052] The AC charging command generation unit 162 receives battery information (SOC, temperature) 27S from the battery 10's BMU 27 via CAN transmission. Based on the battery information (SOC, temperature) 27S, the table data recorded in the vehicle controller 16, and the maximum performance data of the on-board charger 20, the AC charging command generation unit 162 generates a current command 162S1 and an upper limit voltage command 162S2.

[0053] The charging state determination unit 163 stores its own state, and the initial state after startup is the AC charging stopped state. When the AC charging button 21 is pressed while the AC charging stopped state is activated, the charging state determination unit 163 switches to the charging operation state, and when the AC charging button 21 is pressed while the charging operation state is activated, it returns to the charging stopped state. In the charging stopped state, the charging state determination unit 163 changes the value of the current command 162S1 input from the AC charging command generation unit 162 to 0 and outputs the changed value of 0 as the current command 163S1. On the other hand, in the charging operation state, the current command 162S1 input from the AC charging command generation unit 162 is output as the current command 163S1.

[0054] The current command 163S1 output from the charging state determination unit 163 is transmitted to the on-board charger 20 via CAN communication. The on-board charger 20 does not charge if the current command 163S1 is 0, and charges if the current command 163S1 is greater than 0. In this way, the operator can switch between operation and stop for charging by operating the AC charging button 21.

[0055] Figure 7 is a functional block diagram illustrating the functions of the vehicle controller 16 in rapid charging mode. The hydraulic excavator 1 does not have an input device that can be operated in rapid charging mode, and the operator operates it using the input device of the external charger 22 (in the example shown in Figure 7, the control panel 25).

[0056] The rapid charging command generation unit 164 receives battery information (SOC, temperature) 27S from the battery 10's BMU 27 via CAN transmission. Based on the battery information (SOC, temperature) 27S, table data recorded in the vehicle controller 16, and data on the maximum performance of the on-board charger 20, the rapid charging command generation unit 164 generates a current command 164S1 and an upper limit voltage command 164S2. The current command 164S1 and the upper limit voltage command 164S2 are transmitted from the rapid charging port 23 to the external charger 22 via the CP communication line 34.

[0057] The charge control unit 220 of the external charger 22 stores the maximum performance of the external charger 22. The charge control unit 220 generates a new current command from that maximum performance and the received current command 164S1. When an operator operates the operation panel 25 provided on the external charger 22, an operation signal is input to the charge control unit 220. For example, when the operation panel 25 is set to start charging, the charge control unit 220 performs the charging operation based on the newly generated current command and the upper limit voltage command 164S2. Also, when the operation panel 25 is set to stop charging, the charge control unit 220 stops the charging operation. In this way, the operator can switch between operation and stop for rapid charging by operating the operation panel 25 of the external charger 22.

[0058] Figure 8 is a functional block diagram illustrating the functions of the vehicle controller 16 in AC power supply assist mode. In AC power supply assist mode, the vehicle controller 16 receives input of the START signal 36S from the key cylinder 36, the dial operation amount signal 37S from the pump control dial 37, and the signal 21S from the AC charging button 21. The START signal 36S is input to the key start detection unit 161 of the vehicle controller 16, the dial operation amount signal 37S is input to the rotation speed command generation unit 160, and the signal 21S is input to the charging state determination unit 163. In addition, battery information (SOC, temperature) 27S is input from the BMU 27 of the battery 10 via CAN transmission to the AC charging command generation unit 162.

[0059] The rotation speed command generation unit 160, the key start detection unit 161, the AC charging command generation unit 162, and the charging state determination unit 163 have the same functions as the vehicle body controller 16 shown in Figures 5 and 6.

[0060] In other words, as in the case of Figure 5, the key start detection unit 161 outputs a value of 0 as the rotation speed command 161S while there is no input of the START signal 36S, and after the input of the START signal 36S, it outputs the rotation speed command 160S input from the rotation speed command generation unit 160 as the rotation speed command 161S. The inverter 17 controls the rotation speed of the electric motor 7 based on the rotation speed command 161S. As a result, the hydraulic pump 8 and the pilot pump 14 are driven, and pressurized oil is supplied to the control valve unit 9 and the lock valve 13.

[0061] Also, similar to the case in Figure 6, the charging state determination unit 163 switches to the charging operation state when the AC charging button 21 is pressed while the AC charging is stopped, and returns to the charging stop state when the AC charging button 21 is pressed while the charging operation state is active. In the charging stop state, the charging state determination unit 163 changes the value of the current command 162S1 input from the AC charging command generation unit 162 to 0 and outputs the changed value of 0 as the current command 163S1. On the other hand, in the charging operation state, the current command 162S1 input from the AC charging command generation unit 162 is output as the current command 163S1 as is. The onboard charger 20 does not supply power when the current command 163S1 is 0, and supplies power when the current command 163S1 is greater than 0.

[0062] As mentioned above, if the amount of power supplied by the onboard charger 20 is greater than the power consumption of the inverter 17, the excess amount is supplied to the battery 10 and the battery 10 is charged. On the other hand, if the amount of power supplied by the onboard charger 20 is less than the power consumption of the inverter 17, all the power output from the onboard charger 20 is supplied to the inverter 17.

[0063] Thus, in AC power supply assist mode, charging of the battery 10 and operation of the hydraulic excavator 1 can be performed simultaneously when the connection plug is inserted into the AC power supply port 19. Furthermore, the charging operation can be switched on and off by operating the AC charging button 21.

[0064] As described above, the operator can select the appropriate operating mode from four operating modes (battery-powered mode, AC charging mode, rapid charging mode, and AC power supply assist mode) depending on the work situation. For example, if the battery 10 is low but work by the hydraulic excavator 1 is required, selecting the AC power supply assist mode allows the hydraulic excavator 1 to perform work (excavation, slewing, and driving) while the battery 10 is being charged by the onboard charger 20. Also, if the battery 10 has sufficient charge, the battery-powered mode can be selected, and if it is insufficient and there is enough time to perform charging work, the AC charging mode or rapid charging mode can be selected. In this way, by selecting the operating mode according to the situation, it is possible to reduce the downtime of the hydraulic excavator 1.

[0065] Furthermore, in the case of the electric hydraulic excavator 1, it is sometimes operated in a way that charges the excavator by rapid charging during breaks in work to ensure sufficient operating time after work resumes. In this case, the operator connects the DC power supply cable 221 to the rapid power supply port 23, and rapid charging is performed. However, there is a possibility that a third party other than the operator who connected the DC power supply cable 221 may board the hydraulic excavator 1 and attempt to resume work without knowing that the DC power supply cable 221 is connected to the hydraulic excavator 1. However, in this embodiment, in rapid charging mode, the inverter start process and the connection process of the lock valve permission relay 15 are not executed, so digging, slewing, and traveling operations are prohibited. Therefore, even if a third party boards the hydraulic excavator 1 and attempts to resume work while it is charging as described above, the operation of the hydraulic excavator 1 is prohibited. In other words, the operation of the hydraulic excavator 1 while the DC power supply cable 221 is connected is prevented.

[0066] In any of the four operating modes described above, the system automatically sets to the required operating mode when the operator performs the necessary preparatory work (such as turning the key cylinder 36 to the ON position or connecting the connection plug to the power supply port). Therefore, the operator does not need to perform any special selection operations to choose an operating mode.

[0067] Furthermore, for example, a "No Work" sign may be placed near the rapid charging port 23, and a "Work Allowed" sign may be placed near the AC charging port 19. These signs will be visible to the operator when connecting the power cable, prompting them to take precautions during work. This will improve safety during work while charging.

[0068] (Modified Version) In the above-described embodiment, as shown in Figure 4, when the connection plug 222 is connected to the rapid charging port 23, the system is set to rapid charging mode regardless of whether a key-on signal is detected or whether the AC power port is inserted. In this case, in the rapid charging mode startup process (steps S31 to S34) in the startup sequence shown in Figure 3, only the startup process for the external charger 22 is performed, and the startup process is performed to allow only rapid charging using the external charger 22. That is, when rapid charging is performed by the external charger 22, not only is the operation of the hydraulic excavator 1 not permitted, but power supply from the AC power port 19 is also not permitted.

[0069] On the other hand, in the modified configuration, the operation of the hydraulic excavator 1 is not permitted, but if the AC power supply cable 181 is connected to the AC power supply port 19, power supply from the AC power supply port 19 is conditionally permitted. For example, when charging the battery 10, rapid charging is prioritized, and charging coordination between rapid charging and AC charging is performed depending on the charging status. In the modified configuration, the rapid charging mode startup process (steps S31 to S34) in Figure 3 is changed as shown in Figure 9. In the rapid charging mode startup process shown in Figure 9, a process to start the on-board charger 20 (steps S35, S36) is added so that AC charging is possible. The processes in steps S35 and S36 are the same as steps S23 and S24 in Figure 3, so the explanation of the process content is omitted.

[0070] As a specific example of charging coordination, the following control method can be considered: When the State of Charge (SOC) of battery 10 is low and the battery voltage during charging does not exceed the target charging voltage, and voltage control is not required, charging is performed using current control with both AC charging and fast charging. When the SOC is high and the battery voltage during charging exceeds the target charging voltage, and voltage control is required, AC charging is not performed, and charging is performed using only fast charging with voltage control.

[0071] Furthermore, the rapid charger (external charger 22) is designed to charge only when connected to the rapid charger, so there is a risk that it may not be able to control properly if other voltage control systems are introduced. For this reason, in the embodiment described above, the system is configured not to allow power supply from the AC power supply port 19 in rapid charging mode (Figure 3).

[0072] In the embodiment described above, two means are used simultaneously to prohibit the operation of the hydraulic excavator 1: maintaining the closed state of the lock valve 13 and stopping the electric motor 7. However, a configuration using only one of these means is also acceptable. Furthermore, while maintaining the closed state of the lock valve 13 and stopping the electric motor 7 are implemented in software, these can also be implemented using an electrical circuit. For example, a relay that operates from a connected state to a released state in response to an insertion detection signal from the rapid power supply port 23 can be used to interrupt the operation circuit of the lock valve 13 and the start signal of the inverter 17.

[0073] The embodiments and modifications of the present invention described above provide the following effects.

[0074] (1) As shown in Figures 1 and 2, the work machine (hydraulic excavator 1) is driven by an electric motor 7 and includes a battery 10 that supplies power to the electric motor 7, and a first power supply port (AC power supply port 19) and a second power supply port (rapid power supply port 23) to which power supply cables (AC power supply cable 181 and DC power supply cable 221) for supplying power from an external power supply 18 and an external charger 22 to the battery 10 are connected. When the AC power supply cable 181 is connected to the AC power supply port 19, driving by the electric motor 7 is permitted, and when the DC power supply cable 221 is connected to the rapid power supply port 23, driving by the electric motor 7 is prohibited.

[0075] When the battery 10 needs charging, it can be charged via the first power supply port if the work machine needs to be driven, and via the second power supply port if the work machine does not need to be driven. In other words, the operator can select the power supply port according to the situation, thereby reducing the downtime of the hydraulic excavator 1. Furthermore, by connecting the power supply cables (AC power supply cable 181, DC power supply cable 221) that supply power to the battery 10 to the first power supply port (AC power supply port 19) and the second power supply port (rapid power supply port 23), respectively, it is possible to prevent a third party from starting work on the hydraulic excavator 1 without knowing that it is being charged.

[0076] (2) In (1) above, as shown in Figures 2 to 4, a detection device (vehicle controller 16) may be provided to detect the connection of power supply cables to the AC power supply port 19 and the rapid power supply port 23. The vehicle controller 16 (control device) permits driving by the electric motor 7 when the detection device detects that a power supply cable has been connected to the AC power supply port 19, and prohibits driving by the electric motor 7 when the detection device detects that a power supply cable has been connected to the rapid power supply port 23. With this configuration, driving by the electric motor 7 is automatically permitted or prohibited based on the detection result of the vehicle controller 16, which is the detection device.

[0077] (3) In (2) above, as shown in Figures 2, 4, 9, etc., when the vehicle controller 16 detects that power cables are connected to both the AC power port 19 and the rapid power port 23, it prioritizes control during power supply via the rapid power port 23 (rapid charging via only the rapid power port 23, stopping the operation of the hydraulic excavator 1). When power cables are connected to both the AC power port 19 and the rapid power port 23, control during power supply via the second power port takes priority and driving by the electric motor is prohibited, thereby preventing the power cables from coming loose due to operation.

[0078] (4) In (3) above, by making the rapid power supply port 23 a power supply port for rapid charging, the downtime of the electric hydraulic excavator 1 can be reduced by charging using the rapid power supply port 23.

[0079] (5) In (3) above, as shown in Figures 2 to 4, the vehicle controller 16 prohibits driving by the electric motor 7 and also prohibits power supply from the AC power outlet 19. By charging the battery 10 only by rapid charging, stable charging control can be achieved.

[0080] (6) In (1) above, as shown in Figure 2, etc., the system includes a hydraulic pump 8 driven by an electric motor 7 to supply pressurized oil, a control valve unit 9 that distributes the pressurized oil from the hydraulic pump 8 to a plurality of actuators that drive the work device, and a lock valve 13 that can shut off the pilot pressure system that controls the control valve unit 9. When the DC power supply cable 221 is connected to the rapid power supply port 23, the lock valve 13 shuts off the pilot pressure system or stops the electric motor 7.

[0081] By connecting the power supply cable 221 to the rapid power supply port 23, the pilot pressure system can be shut off by the lock valve 13, or the electric motor 7 can be stopped, thereby preventing the hydraulic excavator 1 from operating. By preventing the hydraulic excavator 1 from operating during rapid charging, the force applied to the power supply cable associated with the operation can be prevented, making the charging process safer and more reliable.

[0082] (7) In (1) above, as shown in Figure 2, the hydraulic excavator 1 includes a first charger (onboard charger 20) that receives power from a first power supply port (AC power supply port 19) and outputs a charging current to the battery 10, and a second charger that receives power from a second power supply port (rapid power supply port 23) and outputs a charging current to the battery 10. In the embodiment described above, the second charger is configured as an external charger 22, but it may also be a charger that is mounted on the body of the hydraulic excavator 1.

[0083] 1... Hydraulic excavator (working machine), 7... Electric motor, 8... Hydraulic pump, 9... Control valve unit, 10... Battery, 11... Operating lever, 13... Lock valve, 14... Pilot pump, 15... Lock valve permission relay, 16... Vehicle controller (detection unit, control unit), 17... Inverter, 19... AC power supply port (first power supply port), 20... Onboard charger (first charger), 21... AC charging button, 22... External charger (second charger), 23... Rapid power supply port (second power supply port), 36... Key cylinder, 181... AC power supply cable, 221... DC power supply cable

Claims

1. An electrically operated work machine driven by an electric motor, comprising: a battery that supplies power to the electric motor; a first power supply port and a second power supply port to which a power supply cable for supplying power from an external power source to the battery is connected, wherein when the power supply cable is connected to the first power supply port, driving by the electric motor is permitted, and when the power supply cable is connected to the second power supply port, driving by the electric motor is prohibited.

2. An electric work machine according to claim 1, comprising: a detection device for detecting the connection of power supply cables to the first power supply port and the second power supply port; and a control device that permits driving by the electric motor when the detection device detects the connection of a power supply cable to the first power supply port, and prohibits driving by the electric motor when the detection device detects the connection of a power supply cable to the second power supply port.

3. An electric work machine according to claim 2, wherein the control device, when the detection device detects that power supply cables are connected to both the first power supply port and the second power supply port, prioritizes control when power is supplied via the second power supply port.

4. An electric work machine according to claim 3, wherein the power supply from the second power supply port is a power supply port for rapid charging.

5. An electric work machine according to claim 3, wherein the control device prohibits driving by the electric motor and also prohibits power supply from the first power supply port.

6. An electric work machine according to claim 1, comprising: a hydraulic pump driven by the electric motor and supplying pressurized oil; a control valve unit that distributes the pressurized oil from the hydraulic pump to a plurality of actuators that drive a work device; and a lock valve capable of shutting off a pilot pressure system that controls the control valve unit, wherein when the power supply cable is connected to the second power supply port, the lock valve shuts off the pilot pressure system or stops the electric motor.

7. An electric work machine according to claim 1, comprising: a first charger that receives power from the first power supply port and outputs a charging current to the battery; and a second charger that receives power from the second power supply port and outputs a charging current to the battery.

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