Electric work machinery

Abstract

To enable battery maintenance to be performed at appropriate timing.SOLUTION: A hydraulic excavator as an electric work machine comprises a charger that charges a battery by supplying power to it from an external power source, an electric motor driven by power supplied from the battery, a control unit that manages a physical quantity indicating an operating state of the electric motor as first operating information, and manages a physical quantity indicating an operating state including charging and discharging of the battery as second operating information, and an output unit that outputs the first operating information and the second operating information.SELECTED DRAWING: Figure 2

Description

Technical Field

[0006] , ,

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

Background Art

[0002] Conventionally, a maintenance timing notification device for construction machines has been disclosed. For example, in the notification device of Patent Document 1, when the actual operating time of the engine reaches the maintenance timing, it notifies the driver or administrator for each maintenance item.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, in addition to hydraulic excavators that drive hydraulic actuators using the power of an engine, many hydraulic excavators (electric excavators) that drive hydraulic actuators using the power of a battery are also being utilized. In an electric excavator, an electric motor is driven by the power of a battery to rotate a hydraulic pump, and hydraulic oil is supplied to the hydraulic actuator by this to drive the hydraulic actuator.

[0005] In an electric excavator, since the hydraulic pump is driven by the electric motor as described above, the operating time of the electric motor can be regarded as the operating time of the hydraulic pump. Therefore, by managing the operating time of the electric motor, the maintenance timing of the hydraulic system including the hydraulic pump can be managed, and thus the maintenance of the hydraulic system can be performed at an appropriate timing.

[0006] On the other hand, batteries degrade not only during discharge, that is, while the electric motor is running, but also during charging. Therefore, if maintenance timing for batteries is managed based on the operating time of the electric motor, as with hydraulic systems, it will not be possible to perform maintenance at an appropriate time that takes into account the degradation that occurs during charging.

[0007] This invention was made to solve the above-mentioned problems, and its objective is to provide an electric work machine that allows battery maintenance to be performed at the appropriate time. [Means for solving the problem]

[0008] An electric work machine according to one aspect of the present invention comprises a charger that supplies power to a battery from an external power source to charge the battery, an electric motor driven by power supplied from the battery, a control unit that manages a physical quantity indicating the operating state of the electric motor as first operating information and a physical quantity indicating the operating state including charging and discharging of the battery as second operating information, and an output unit that outputs the first operating information and the second operating information, wherein the control unit manages the operating time of the electric motor as the first operating information and manages the operating time of the battery as the second operating information. [Effects of the Invention]

[0009] With the above configuration, battery maintenance can be performed at the appropriate time. [Brief explanation of the drawing]

[0010] [Figure 1] This is a side view showing the schematic configuration of a hydraulic excavator, which is an example of an electric work machine according to one embodiment of the present invention. [Figure 2] This is a block diagram schematically showing the configuration of the control system and hydraulic system of the hydraulic excavator described above. [Figure 3] This is an explanatory diagram showing an example of a display on the display unit of the hydraulic excavator described above. [Figure 4] This is an explanatory diagram showing another example of the display in the above-mentioned display unit. [Figure 5] This is a schematic diagram illustrating examples of the relay's energization status, the electric motor's operating status, the charger's operating status, and the battery's operating status in both charging mode and battery mode. [Figure 6] This is a schematic diagram illustrating examples of the relay energization status, electric motor operating status, charger operating status, and battery operating status in charging mode, battery mode, and power supply combined mode, respectively. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings.

[0012] [1. Electric working machines] Figure 1 is a schematic side view showing the configuration of a hydraulic excavator 1, which is an example of an electric work machine of this embodiment. The hydraulic excavator 1 comprises a lower traveling body 2, a work machine 3, and an upper rotating body 4.

[0013] Here, in Figure 1, directions are defined as follows. First, the direction in which the lower vehicle 2 moves in a straight line is defined as the front-rear direction, with one side being defined as "front" and the other as "rear". In Figure 1, as an example, the side of the vehicle motor 22 relative to the blade 23 is shown as "front". Also, the lateral direction perpendicular to the front-rear direction is defined as the left-right direction. In this case, the left side is defined as "left" and the right side as viewed from the operator (driver, pilot) seated in the cockpit 41a. Furthermore, the direction of gravity perpendicular to the front-rear and left-right directions is defined as the up-down direction, with the upstream side of the direction of gravity being defined as "up" and the downstream side as "down".

[0014] The lower travel body 2 comprises a pair of left and right crawlers 21 and a pair of left and right travel motors 22. Each travel motor 22 is a hydraulic motor. The left and right travel motors 22 drive the left and right crawlers 21 respectively, allowing the hydraulic excavator 1 to move forward and backward. The lower travel body 2 is equipped with a blade 23 for leveling work and a blade cylinder 23a. The blade cylinder 23a is a hydraulic cylinder that rotates the blade 23 in the vertical direction.

[0015] The work machine 3 comprises a boom 31, an arm 32, and a bucket 33. By independently driving the boom 31, arm 32, and bucket 33, excavation work such as soil and sand can be performed.

[0016] The boom 31 is rotated by the boom cylinder 31a. The boom cylinder 31a is supported at its base end at the front of the upper slewing body 4 and is movable in an extendable and retractable manner. The arm 32 is rotated by the arm cylinder 32a. The arm cylinder 32a is supported at its base end at the tip of the boom 31 and is movable in an extendable and retractable manner. The bucket 33 is rotated by the bucket cylinder 33a. The bucket cylinder 33a is supported at its base end at the tip of the arm 32 and is movable in an extendable and retractable manner. The boom cylinder 31a, the arm cylinder 32a, and the bucket cylinder 33a are composed of hydraulic cylinders.

[0017] The upper rotating body 4 is configured to rotate relative to the lower traveling body 2 via a rotating bearing (not shown). The upper rotating body 4 houses a control unit 41, a turntable 42, a rotating motor 43, an engine room 44, etc. The upper rotating body 4 rotates via the rotating bearing, driven by the rotating motor 43, which is a hydraulic motor.

[0018] A plurality of hydraulic pumps 71 (see FIG. 2) are arranged in the upper revolving body 4. Each hydraulic pump 71 is driven by an electric motor 61 (see FIG. 2) inside the engine room 44. Each hydraulic pump 71 supplies hydraulic oil (pressure oil) to hydraulic motors (for example, left and right traveling motors 22, slewing motor 43), and hydraulic cylinders (for example, blade cylinder 23a, boom cylinder 31a, arm cylinder 32a, bucket cylinder 33a). Hydraulic motors and hydraulic cylinders that are driven by supplying hydraulic oil from an arbitrary hydraulic pump 71 are collectively referred to as a hydraulic actuator 73 (see FIG. 2).

[0019] A driver's seat 41a is arranged in the control unit 41. Various levers 41b are arranged around the driver's seat 41a. When the operator sits on the driver's seat 41a and operates the lever 41b, the hydraulic actuator 73 is driven. Thereby, traveling of the lower traveling body 2, leveling work by the blade 23, excavation work by the work implement 3, slewing of the upper revolving body 4, etc. can be performed.

[0020] A battery 53 is attached to the upper revolving body 4. The battery 53 is composed of, for example, a lithium-ion battery that outputs a high voltage, and is used to drive the electric motor 61. Further, a power supply port (not shown) is provided in the upper revolving body 4. The above power supply port and the external power source 51 are connected via a power supply cable 52. Thereby, it is also possible to charge the battery 53.

[0021] When the lower traveling body 2, the work implement 3, and the upper revolving body 4 are collectively referred to as a machine body BA, the machine body BA may be driven by using both equipment driven by electric power and hydraulic equipment. That is, the machine body BA may include an electric traveling motor, an electric cylinder, an electric slewing motor, etc. in addition to hydraulic equipment such as the hydraulic actuator 73.

[0022] [2. Configuration of the control system and the hydraulic system] Figure 2 is a schematic block diagram showing the configuration of the control system and hydraulic system of the hydraulic excavator 1. In Figure 2, dashed arrows indicate the transmission path of detection signals, and solid arrows indicate the transmission path of control signals (commands). The hydraulic excavator 1 is equipped with an electric motor 61. The electric motor 61 is driven by power supplied from the battery 53.

[0023] The rotational speed of the electric motor 61 is detected by the rotational speed detection sensor 61a. In other words, the hydraulic excavator 1 is equipped with a rotational speed detection sensor 61a that detects the rotational speed of the electric motor 61. The rotational speed information of the electric motor 61 detected by the rotational speed detection sensor 61a is input to the ECU 80, which will be described later.

[0024] The hydraulic excavator 1 is equipped with a charger 62. The charger 62 converts the AC voltage supplied from the external power source 51 via the power supply cable 52 (see Figure 1) into a DC voltage. The DC voltage (power) output from the charger 62 is supplied to the battery 53. The battery 53 is charged by the power supplied from the external power source 51 to the battery 53 via the charger 62. In other words, the hydraulic excavator 1 is equipped with a charger 62 that charges the battery 53 by supplying power from the external power source 51 to the battery 53.

[0025] The hydraulic excavator 1 is equipped with an inverter 63. The inverter 63 converts the DC voltage supplied from the battery 53 into AC voltage and supplies it to the electric motor 61. This causes the electric motor 61 to rotate. The supply of AC voltage (current) from the inverter 63 to the electric motor 61 is performed based on a rotation command (control signal) output from the ECU 80.

[0026] The power supplied from the battery 53 to the electric motor 61 passes through the first circuit E1. The inverter 63 described above is located between the battery 53 and the electric motor 61 in the first circuit E1. The power supplied from the charger 62 to the battery 53 passes through the second circuit E2. The second circuit E2 merges with the first circuit E1 at a merging point Ec located between the battery 53 and the inverter 63. Therefore, the power output from the charger 62 is supplied to the battery 53 via the second circuit E2 and the merging point Ec. In other words, the hydraulic excavator 1 comprises a first circuit E1 that supplies power from the battery 53 to the electric motor 61, and a second circuit E2 that is connected to the charger 62 and merges with the first circuit E1 at the merging point Ec.

[0027] Furthermore, the hydraulic excavator 1 is equipped with a relay 64. The relay 64 is located in the first circuit E1 between the junction Ec and the battery 53. Based on the control of the ECU 80, the relay 64 switches the first circuit E1 between a connected state (electrically connecting the battery 53 and the inverter 63) and a disconnected state (electrically disconnecting the battery 53 and the inverter 63). The relay 64 also detects the above connected state or disconnected state and outputs a detection signal to the ECU 80. As a result, the ECU 80 can manage the connected time or disconnected time of the relay 64 based on the detection signal.

[0028] Furthermore, the hydraulic excavator 1 is equipped with a hydraulic system 70. The hydraulic system 70 includes a hydraulic pump 71, a control valve 72, and a hydraulic actuator 73.

[0029] The hydraulic pump 71 is connected to the rotating shaft (output shaft) of the electric motor 61 and is driven by the rotation of the electric motor 61. The hydraulic pump 71 is, for example, a variable displacement pump, but it may also be a fixed displacement pump. Multiple hydraulic pumps 71 are provided as described above, but in Figure 2 only one hydraulic pump 71 is shown as an example. The hydraulic pump 71 supplies hydraulic fluid from a hydraulic fluid tank (not shown) as pressurized oil to the hydraulic actuator 73 via a control valve 72. This drives the hydraulic actuator 73. The control valve 72 is a directional control valve that controls the flow direction and flow rate of the pressurized oil supplied from the hydraulic pump 71 to the hydraulic actuator 73, and is provided corresponding to each hydraulic actuator 73.

[0030] Thus, the hydraulic excavator 1 includes a hydraulic system 70 that includes a hydraulic pump 71 driven by an electric motor 61 and a hydraulic actuator 73 to which pressurized oil is supplied by the hydraulic pump 71.

[0031] The hydraulic excavator 1 is further equipped with an ECU (Electronic Control Unit) 80. The ECU 80 is a control unit that controls various parts of the hydraulic excavator 1 and is composed of, for example, a CPU (Central Processing Unit), a memory unit, etc. The ECU 80 generates rotation commands for the electric motor 61 and supplies them to the inverter 63.

[0032] Furthermore, detection signals from various parts of the hydraulic excavator 1 are input to the ECU 80. For example, the electric motor 61, charger 62, inverter 63, and battery 53 each have built-in sensors (not shown) that detect their own operating status, including whether or not there is an abnormality, and detection signals from these sensors are input to the ECU 80. As a result, the ECU 80 can recognize the operating status of the electric motor 61, charger 62, inverter 63, and battery 53 based on the above detection signals.

[0033] For example, the ECU 80 can recognize the time the electric motor 61 is driven as its operating time based on detection signals from sensors built into the electric motor 61. The ECU 80 can also recognize the time the charger 62 is operating (for example, the charging time of the battery 53) based on detection signals from sensors built into the charger 62. Furthermore, the ECU 80 can recognize the time the battery 53 is operating (for example, the charging and discharging time of the battery 53) based on detection signals from sensors built into the battery 53, and can also recognize the remaining charge level of the battery 53.

[0034] The ECU 80 stores and manages first operation information and second operation information in its internal memory. The first operation information is information of physical quantities indicating the operating status of the electric motor 61, and includes, for example, the operating time of the electric motor 61 as described above. The first operation information may also include information of the rotational speed of the electric motor 61 detected by the rotational speed detection sensor 61a. On the other hand, the second operation information is information of physical quantities indicating the operating status of the battery 53, and includes, for example, the operating time of the battery 53 (charging time + discharging time) as described above. The second operation information may also include the remaining charge of the battery 53.

[0035] Thus, the hydraulic excavator 1 is equipped with an ECU 80 as a control unit that manages physical quantities indicating the operating state of the electric motor 61 as first operating information based on the output signal of the electric motor 61, and manages physical quantities indicating the operating state of the battery 53, including charging and discharging, as second operating information based on the output signal of the battery 53.

[0036] The hydraulic excavator 1 further includes an output unit 90. The output unit 90 outputs first operation information and second operation information managed by the ECU 80. Such an output unit 90 includes a display unit 91 and a communication unit 92.

[0037] The display unit 91 is, for example, a liquid crystal display device, and under the control of the ECU 80, it displays first operation information and second operation information. That is, the output unit 90 includes the display unit 91 that displays the first operation information and second operation information. The communication unit 92 is an interface for communicating with an external terminal and is composed of an antenna, a transmitting and receiving circuit, etc.

[0038] Although not shown in the diagram, the hydraulic excavator 1 is equipped with a hydraulic fluid temperature sensor for detecting the temperature of the hydraulic fluid, and a cooling water temperature sensor for detecting the temperature of the cooling water flowing through the cooling system for cooling the electric motor 61, etc.

[0039] Figure 3 shows an example of the display on the display unit 91. As shown in the figure, the display unit 91 displays the hydraulic oil temperature detected by the hydraulic oil temperature sensor, the remaining charge of the battery 53, and the coolant temperature detected by the coolant temperature sensor, respectively, as information 101 to 103. In addition, the display unit 91 displays the operating time T1 of the electric motor 61 as first operating information, along with an icon M1 representing the electric motor 61, and displays the operating time T2 of the battery 53 as second operating information, along with an icon M2 representing the battery 53. In the example shown in the figure, the operating time T1 is shown to be "300H" and the operating time T2 is shown to be "500H". Note that "H" represents time (hour) (the same applies below).

[0040] As in this embodiment, the ECU 80 manages a physical quantity indicating the operating state of the electric motor 61 (for example, the operating time T1 of the electric motor 61) as first operating information, and manages a physical quantity indicating the operating state of the battery 53, including charging and discharging (for example, operating time T2 = charging time + discharging time) as second operating information. In this case, by outputting the first operating information, the operator, etc. (operator, surrounding workers, system administrator, etc.) can perform maintenance (inspection) of the hydraulic system 70 (for example, hydraulic pump 71) at an appropriate timing based on the outputted first operating information. Furthermore, by outputting the second operating information, the operator, etc. can perform maintenance on the battery 53 at an appropriate timing that takes into account not only the deterioration during discharging of the battery 53 but also the deterioration during charging, that is, at an appropriate timing independent of the maintenance timing of the hydraulic system 70, based on the second operating information, and can replace the battery 53 if necessary.

[0041] In particular, the physical quantity indicating the operating state of the electric motor 61 includes the operating time T1 of the electric motor 61. Since the hydraulic pump 71 is driven by the electric motor 61, the operating time of the hydraulic system 70, including the hydraulic pump 71, is considered to be approximately the same as the operating time of the electric motor 61. Therefore, by having the ECU 80 manage the operating time T1 of the electric motor 61 as first operating information, when the output unit 90 outputs the first operating information, operators can perform maintenance on the hydraulic system 70 at an appropriate timing based on the first operating information, i.e., the operating time of the electric motor 61.

[0042] Furthermore, the physical quantity indicating the operating status of the battery 53 includes the sum of the battery 53's charging time and discharge time. In this case, when the output unit 90 outputs the second operating information, the operator can perform maintenance on the battery 53 at an appropriate time based on the sum of the battery 53's charging time and discharge time. In other words, maintenance on the battery 53 can be performed at an appropriate time that takes into account not only the degradation during discharge but also the degradation during charging.

[0043] Furthermore, the physical quantity indicating the operating state of the battery 53 is not limited to the sum of the charging time and discharging time of the battery 53 as described above. For example, the sum of the total charge amount (absolute value) obtained by accumulating the charge amount of the battery 53 over a predetermined period for each predetermined period, and the total discharge amount (absolute value) obtained by accumulating the discharge amount of the battery 53 over a predetermined period for each predetermined period, may be treated as the physical quantity indicating the operating state of the battery 53. Even in this case, when the output unit 90 outputs the second operating information, the operator, etc., can perform maintenance on the battery 53 at an appropriate timing, taking into account not only the degradation due to discharge but also the degradation due to charging, based on the outputted second operating information, that is, the sum of the total charge amount and total discharge amount of the battery 53.

[0044] Furthermore, in this embodiment, the output unit 90 includes a display unit 91 that displays first and second operation information. This allows, for example, an operator to easily determine the timing for performing maintenance on the hydraulic system 70 by looking at the first operation information (e.g., operating time T1) displayed on the display unit 91, and to easily determine the timing for performing maintenance on the battery 53 by looking at the second operation information (e.g., operating time T2) displayed on the display unit 91.

[0045] Furthermore, in this embodiment, the output unit 90 includes a communication unit 92. In this configuration, the ECU 80 outputs the first operation information and the second operation information to an external terminal via the communication unit 92, allowing the system administrator handling the terminal to recognize the first operation information and the second operation information. As a result, the administrator can appropriately manage the timing of maintenance of the hydraulic system 70 based on the first operation information, and further manage the timing of maintenance considering the degradation of the battery 53 due to discharge and charging based on the second operation information.

[0046] Incidentally, the ECU 80 may determine whether at least one of the physical quantities managed as first operational information and the physical quantities managed as second operational information has reached a specified value, and if it has reached a specified value, it may display on the display unit 91 that the specified value has been reached. For example, Figure 4 shows another example of the display on the display unit 91. In this figure, when the operating time T1 of the electric motor 61 reaches a first specified value (e.g., 600H), the display unit 91 flashes to indicate that the operating time T1 has reached the first specified value. In the same figure, when the operating time T2 of the battery 53 reaches a second specified value (e.g., 1000H), the display unit 91 flashes to indicate that the operating time T2 has reached the second specified value.

[0047] In this way, by the ECU 80 controlling the display on the display unit 91, the operator can immediately recognize when a physical quantity managed as first or second operational information has reached a specified value by looking at the display unit 91, and easily recognize that it is time for maintenance on at least one of the hydraulic system 70 and the battery 53. This enables the operator to quickly perform appropriate maintenance, such as inspecting the hydraulic pump 71 or replacing the battery 53.

[0048] Note that Figure 4 shows an example where the operating time T1 and operating time T2 of the electric motor 61 reach their respective specified values ​​(first specified value and second specified value) simultaneously, but they do not necessarily reach them at the same time. In other words, when at least one of the operating time T1 and operating time T2 reaches the specified value, the ECU 80 should notify that the specified value has been reached by flashing the operating time that has reached the specified value on the display unit 91.

[0049] Incidentally, it is desirable for the ECU 80 to manage a physical quantity indicating the operating state of the electric motor 61 when the rotational speed of the electric motor 61 detected by the rotational speed detection sensor 61a exceeds a predetermined value (for example, 10 revolutions / min) as first operating information. In this case, the ECU 80 will display the operating time T1 of the electric motor 61 as the time during which the electric motor 61 is operating with its rotational speed exceeding the predetermined value on the display screen of the display unit 91 shown in Figures 3 and 4.

[0050] By having the ECU 80 manage the first operational information as described above, it is possible to exclude from the first operational information the operating time of the electric motor 61 when it is rotating at a rotational speed below the predetermined value (e.g., very low speed) and is not considered to be in operation, and to manage the operating time of the electric motor 61 when it is considered to be rotating at a rotational speed above the predetermined value as the first operational information. This improves the accuracy of managing the timing of maintenance of the electric motor 61 based on the first operational information.

[0051] [3. Method for obtaining physical quantities that indicate the operating status of the battery] The drive modes of the hydraulic excavator 1 in this embodiment include a charging mode and a battery mode. The charging mode is an operating mode in which the battery 53 is charged by the charger 62. On the other hand, the battery mode is an operating mode in which the electric motor 61 is driven by the power of the battery 53.

[0052] Figure 5 schematically shows an example of the state of relay 64 (connected / disconnected), the operating state of electric motor 61, the operating state of charger 62, and the operating state of battery 53 in charging mode and battery mode, respectively. When the hydraulic excavator 1 is driven in two drive modes, charging mode and battery mode, in charging mode, the battery 53 is charged by the operation of charger 62, so the operating time of charger 62 (2) is the same as the charging time of battery 53 (3). On the other hand, in battery mode, the battery 53 is discharged by the operation of electric motor 61, so the operating time of electric motor 61 (1) is the same as the discharge time of battery 53 (4). Therefore, the sum of the charging time (3) and discharge time (4) of battery 53 is equal to the sum of the operating time of charger 62 (2) and the operating time of electric motor 61 (1). In other words, the physical quantity that indicates the operating state of the battery 53, including charging and discharging (charging time of battery 53 (3) + discharging time of battery 53 (4)), is the sum of the operating time of the charger 62 (2) and the operating time of the electric motor 61 (1).

[0053] Therefore, when the hydraulic excavator 1 is driven in charging mode or battery mode as described above, the ECU 80 can easily obtain and manage a physical quantity indicating the operating state of the battery 53 (charging time (3) + discharge time (4)) by managing the sum of the operating time of the charger 62 (2) and the operating time of the electric motor 61 (1).

[0054] [4. Other methods for obtaining physical quantities that indicate the battery's operating status] In addition to the charging mode and battery mode described above, the drive modes of the hydraulic excavator 1 may also include a power supply combined mode. The power supply combined mode is a mode in which the electric motor 61 is driven by power supplied from at least one of the external power supply 51 and the battery 53.

[0055] Figure 6 schematically shows examples of the state of relay 64 (connected / disconnected), the operating state of electric motor 61, the operating state of charger 62, and the operating state of battery 53 in charging mode, battery mode, and power supply combined mode, respectively. When the hydraulic excavator 1 is driven in one of the three drive modes—charging mode, battery mode, and power supply combined mode—the physical quantity indicating the operating state of battery 53, including charging and discharging (charging time of battery 53 (D) + discharging time of battery 53 (E)) is not the sum of the operating time of charger 62 (C) and the operating time of electric motor 61 (B), and the same relationship as in Figure 5 cannot be obtained.

[0056] However, in charging mode, battery mode, and power supply combined mode, the battery 53 is charged or discharged, but both charging and discharging occur with the relay 64 connected. Therefore, the sum of the charging time (D) and discharging time (E) of the battery 53 is equal to the connection time (A) of the relay 64. In other words, the physical quantity that indicates the operating state including charging and discharging of the battery 53 (charging time of battery 53 (D) + discharging time of battery 53 (E)) is the connection time (A) of the relay 64.

[0057] Therefore, when the hydraulic excavator 1 is driven in charging mode, battery mode, or power supply combined mode as described above, the ECU 80 can easily obtain and manage a physical quantity (charging time (D) + discharge time (E)) indicating the operating status of the battery 53 by managing the connection time (A) of the relay 64.

[0058] Furthermore, the relationship that the charging time (D) + discharging time (E) of battery 53 is equal to the connection time (A) of relay 64 can also be seen in Figure 5. In other words, when the hydraulic excavator 1 is driven in two drive modes, charging mode and battery mode, the relay 64 is connected in both charging mode and discharging mode. Therefore, in Figure 5, the sum of the charging time (3) and discharging time (4) of battery 53 is equal to the connection time (5) of relay 64. Thus, the above-mentioned effect of easily acquiring and managing a physical quantity indicating the operating state of battery 53 by having the ECU 80 manage the connection time of relay 64 can be obtained even when the hydraulic excavator 1 is driven in two drive modes (charging mode or battery mode), as shown in Figure 5.

[0059] In the above explanation, we used a hydraulic excavator, a type of construction machinery, as an example of an electrically powered work machine. However, the work machine is not limited to a hydraulic excavator; it could be other construction machinery such as a wheel loader, or agricultural machinery such as a combine harvester or tractor.

[0060] Although embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and it can be expanded or modified without departing from the spirit of the invention. [Industrial applicability]

[0061] This invention can be used, for example, in work machinery such as construction machinery and agricultural machinery. [Explanation of Symbols]

[0062] 1. Hydraulic excavator (electric work machine) 51 External power supply 53 batteries 61 Electric motor 62 Charger 61a Rotation speed detection sensor 64 relays 70 Hydraulic System 71 Hydraulic pump 73 Hydraulic Actuator 80 ECU (control unit) 90 Output Department 91 indicates the department E1 Circuit 1 E2 Circuit 2 Ec confluence

Claims

[Claim 1] A charger that supplies power to a battery from an external power source to charge the battery, An electric work machine comprising an electric motor driven by power supplied from the aforementioned battery, A control unit manages a physical quantity indicating the operating state of the electric motor as first operating information, and manages a physical quantity indicating the operating state, including charging and discharging of the battery, as second operating information. It comprises an output unit that outputs the first operation information and the second operation information, The drive mode of the aforementioned electric work machine is: The system includes a charging mode in which the battery is charged by the charger, and a battery mode in which the electric motor is driven by the power of the battery. An electric work machine in which the physical quantity indicating the operating state, including charging and discharging of the battery, is the sum of the operating time of the charger, recognized by the control unit based on a detection signal from a sensor built into the charger, and the operating time of the electric motor, recognized by the control unit based on a detection signal from a sensor built into the electric motor.

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