Power control device

Abstract

This prevents the battery from over-discharging, allowing the work machine to operate until certain conditions are met. [Solution] The controller 70 performs a power-off delay process P2 when the power-off delay condition is met. The power-off delay condition is a condition in which the most recent switch from the power-on state to the power-off state, relative to the power-on state, was performed by a low-charge power-off process P1. The power-off delay process P2 is a process that, even when the low-charge power-off condition is met, keeps the battery 41 in the power-on state until the delay termination condition, which is a condition set in the controller 70, is met.

Description

Technical Field

[0001] The present invention relates to a power control device for controlling a power supply.

Background Art

[0002] For example, Patent Document 1 describes a working machine that operates by the power of a battery. In this working machine, the battery supplies power to an electric motor, and the working machine operates when the electric motor operates.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the charge rate of the battery decreases, the battery may become over-discharged and the battery may deteriorate. On the other hand, when the charge rate of the battery is low, if the battery is turned off (details will be described later), the electric motor may stop operating and the working machine (specifically, part or all of the working machine) may stop operating.

[0005] Therefore, an object of the present invention is to provide a power control device that can suppress over-discharge of the battery and can operate the working machine until a predetermined condition is satisfied.

Means for Solving the Problems

[0006] The power control device comprises a battery, a battery state detection unit, and a controller. The battery supplies power to an electric motor that operates a work machine. The battery state detection unit detects the charge level of the battery. The controller can switch between a power-on state, in which power can be supplied from the battery to the electric motor, and a power-off state, in which power cannot be supplied from the battery to the electric motor. When a low-charge power-off condition is met, the controller performs a low-charge power-off process to switch the battery state from the power-on state to the power-off state. The low-charge power-off condition includes the condition that the charge level of the battery detected by the battery state detection unit is less than or equal to a charge level setting value set in the controller. When a power-off delay condition is met, the controller performs a power-off delay process. The power-off delay condition includes the condition that the most recent switch from the power-on state to the power-off state, relative to the power-on state, was a switch performed by the low-charge power-off process. The power-off delay process is a process that maintains the battery state in the power-on state even when the low-charge power-off condition is met, until the delay termination condition, which is a condition set in the controller, is met. [Effects of the Invention]

[0007] The above power control device can prevent the battery from being over-discharged and allows the work machine to operate until predetermined conditions are met. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side view of the work machine 10 of the power control device 1. [Figure 2] Figure 1 is a block diagram of the power control device 1. [Figure 3] Figure 2 is an explanatory diagram of the low-charge power-off process P1 performed by the controller 70. [Figure 4] Figure 2 is an explanatory diagram of the low-charge, no-operation power-off process P1a performed by the controller 70. [Figure 5] Figure 2 is an explanatory diagram of the power-off delay processing P2 and power-off delay release processing P3 performed by the controller 70 shown. [Figure 6] Figure 2 is an explanatory diagram of the power-off process P4 performed by the controller 70 when there is no operation. [Figure 7] Figure 2 shows a flowchart of the processes performed by the controller 70, including the power-off process P4 for inactivity. [Figure 8] Figure 2 shows a flowchart of the processes performed by the controller 70, including the low-charge, no-operation power-off process P1a. [Modes for carrying out the invention]

[0009] The power control device 1 will be described with reference to Figures 1 to 8.

[0010] The power control device 1 (power control unit) is a device (system) for operating the work machine 10 shown in Figure 1 using electricity. The power control device 1 is a device that controls the power supply for operating the work machine 10. The power control device 1 comprises the work machine 10, an input unit 50 shown in Figure 2, a detection unit 60, a controller 70, and an output unit 80.

[0011] As shown in Figure 1, the work machine 10 is a machine that performs work. The work machine 10 may be a construction machine that performs construction work, or a material handling machine that performs material handling work. The work machine 10 may be, for example, an excavator or a crane. The work machine 10 may be a bulldozer or a wheel loader. The work machine 10 is a machine that is powered by the battery 41 (see Figure 2) (battery-powered work machine) (for example, a battery-powered construction machine). Below, we will mainly describe the case where the work machine 10 is an excavator. The work machine 10 comprises a machine body 10a, an attachment 15, a hydraulic circuit 20 shown in Figure 2, an actuator 30, and an electrical circuit 40.

[0012] As shown in Figure 1, the machine body 10a is the main body of the work machine 10. The machine body 10a comprises a lower body 11 and an upper rotating body 13.

[0013] The lower body 11 supports the upper rotating body 13 so that it can rotate. The lower body 11 may also be a lower traveling body that can travel on a traveling surface (such as the ground). If the lower body 11 is capable of traveling, it may be equipped with crawlers or wheels.

[0014] The upper slewing body 13 is rotatably supported by the lower body 11. The upper slewing body 13 includes a control room 13c. The control room 13c is the part from which a worker (operator) can operate the work machine 10. When the work machine 10 moves in response to the worker's operation, the work machine 10 may be operated (operated from inside) by the worker inside the control room 13c, or it may be remotely controlled from outside the work machine 10. The work machine 10 may also move by automatic control (described later).

[0015] Attachment 15 is the part that performs the work. Attachment 15 performs work on the workpiece. Attachment 15 is attached to the machine body 10a (specifically the upper slewing body 13). For example, attachment 15 comprises a boom 15a, an arm 15b, and a tip attachment 15c. The boom 15a is rotatably (up and down) attached to the upper slewing body 13. The arm 15b is rotatably attached to the boom 15a.

[0016] The tip attachment 15c is provided at the tip of the attachment 15. The tip attachment 15c is rotatably attached to the arm 15b. The tip attachment 15c may be a bucket capable of scooping and excavating workpieces. The tip attachment 15c may be equipped with a device for gripping workpieces (grapple, nibbler, rotating fork, etc.), a device for crushing workpieces (breaker, etc.), or a magnet for attracting metal workpieces.

[0017] The hydraulic circuit 20 (see FIG. 2) is a circuit for driving an actuator 30 (hydraulic actuator) that moves by hydraulic pressure. As shown in FIG. 2, the hydraulic circuit 20 includes a pump 21.

[0018] The pump 21 is rotationally driven by a pump drive motor 45a (described later), sucks in hydraulic oil, and discharges the hydraulic oil. The pump 21 supplies hydraulic oil to the actuator 30 that moves by hydraulic pressure. Only one pump 21 may be provided, or a plurality of pumps 21 may be provided.

[0019] As shown in FIG. 1, the actuator 30 is a device that moves the work machine 10. The actuator 30 may include a hydraulic actuator that moves by hydraulic pressure, or may include an electric actuator that moves by electric power. The actuator 30 may include a motor that generates rotational motion, or may include a linear actuator (for example, a telescopic cylinder) that generates linear motion. The actuator 30 includes a traveling motor 31, a slewing motor 33, a boom cylinder 35a, an arm cylinder 35b, and a tip attachment cylinder 35c.

[0020] The traveling motor 31 moves the lower body 11. The traveling motor 31 may be, for example, a hydraulic motor or an electric motor (the same applies to the slewing motor 33). The slewing motor 33 slews the upper slewing body 13 with respect to the lower body 11. The boom cylinder 35a rotates (rises and falls) the boom 15a in the vertical direction with respect to the upper slewing body 13. The boom cylinder 35a is, for example, a hydraulic cylinder (the same applies to the arm cylinder 35b and the tip attachment cylinder 35c). The arm cylinder 35b rotates the arm 15b with respect to the boom 15a. The tip attachment cylinder 35c rotates the tip attachment 15c with respect to the arm 15b. If the tip attachment 15c itself can be driven, for example, as a device for clamping an object, an actuator 30 for driving the tip attachment 15c may be provided.

[0021] The electrical circuit 40 (see Figure 2) is a circuit for powering the work machine 10 using electricity. The electrical circuit 40 is mounted on the machine body 10a. As shown in Figure 2, the electrical circuit 40 includes a battery 41, a high-voltage DC unit 42, an electric motor inverter 43, an AC unit 44, an electric motor 45, an auxiliary power supply circuit 46, and an auxiliary unit 47.

[0022] Battery 41 outputs power to operate the work machine 10 (see Figure 1 (the same applies to the work machine 10 below)). Battery 41 is the power source for the work machine 10. Battery 41 supplies power to the electric motor 45. If the tip attachment 15c shown in Figure 1 is equipped with a magnet, battery 41 may also supply power to the magnet. In this case, the power supplied to the magnet is included in the "power to operate the work machine 10". As shown in Figure 2, if an auxiliary battery 46b, which will be described later, is provided, and the auxiliary battery 46b is referred to as the "sub-battery", then battery 41 is the "main battery". Battery 41 is a secondary battery, and may be, for example, a lead-acid battery or a lithium-ion battery.

[0023] The high-voltage DC section 42 is the part through which direct current (DC) flows. The high-voltage DC section 42 is configured to supply power from the battery 41 to the motor inverter 43.

[0024] The motor inverter 43 is a device (motor drive device) that drives the motor 45. The motor inverter 43 is configured to be able to receive power from the battery 41. The motor inverter 43 converts the power supplied from the battery 41 (it is a power converter) and supplies the converted power to the motor 45. Specifically, the motor inverter 43 converts the direct current input from the high-voltage DC section 42 into alternating current (AC). The motor 45 inverter outputs the alternating current to the motor 45 via the AC section 44.

[0025] The AC section 44 is the part that supplies alternating current to the motor 45. The AC section 44 is connected to the motor inverter 43 and the motor 45.

[0026] The electric motor 45 is for operating the work machine 10. The electric motor 45 is configured to be able to receive power from the battery 41. The electric motor 45 is driven by the power output from the battery 41. The electric motor 45 is driven by the electric motor inverter 43. There may be only one electric motor 45 or there may be multiple electric motors. The electric motor 45 may be equipped with a device that generates rotational motion (electric motor). For example, the electric motor 45 may be equipped with a motor that is driven by the supply of alternating current (AC motor). The electric motor 45 may be equipped with a device that generates linear motion (linear actuator, electric cylinder). Some or all of the actuators 30 may be electric motors 45 (electric actuators). For example, the slewing motor 33 may be an electric motor 45 or a hydraulic actuator. The actuators 30 other than the slewing motor 33 may also be hydraulic actuators or electric motors 45. The electric motor 45 is equipped with a pump drive motor 45a.

[0027] The pump drive motor 45a is a motor that drives (rotates) the pump 21. When the pump drive motor 45a drives the pump 21, the pump 21 discharges hydraulic fluid, which is supplied to the hydraulically operated actuator 30. Then, the hydraulically operated actuator 30 moves, causing the work machine 10 to move.

[0028] The auxiliary power supply circuit 46 is a circuit for supplying power to the auxiliary equipment 47. For example, the auxiliary power supply circuit 46 may be configured to allow switching the power on and off for each auxiliary equipment 47 individually, or it may be configured to allow switching the power on and off for all auxiliary equipment 47 collectively. The auxiliary power supply circuit 46 may include an auxiliary battery 46b. The auxiliary battery 46b supplies power to the auxiliary equipment 47. The auxiliary battery 46b is a rechargeable battery.

[0029] Auxiliary equipment 47 is an electric-powered device that is different from the electric motor 45. Auxiliary equipment 47 may include some or all of the following: input unit 50, detection unit 60, controller 70 (e.g., ECU; Electronic Control Unit), and output unit 80. Auxiliary equipment 47 may include, for example, an air conditioner in the driver's cab 13c (see Figure 1), and may include, for example, the compressor of the air conditioner. Auxiliary equipment 47 may include a cooling fan (e.g., a fan that cools the electric motor 45). Auxiliary equipment 47 may be powered by electricity supplied from the battery 41 that supplies power to the electric motor 45. Auxiliary equipment 47 may also be powered by electricity supplied from an auxiliary battery 46b that is provided separately from the battery 41 that supplies power to the electric motor 45.

[0030] The input unit 50 is an input device for inputting information. The input unit 50 is operated by an operator and outputs information (signals) corresponding to the operation. The input unit 50 outputs information to the controller 70. The input unit 50 may be equipped with a touch panel, a mouse, a keyboard, or switches. The input unit 50 may be equipped with a device for voice input. The input unit 50 may be installed on a tablet, a smartphone, or a personal computer. Part or all of the input unit 50 may be mounted on the work machine 10 or located outside the work machine 10. For example, the input unit 50 may be installed in the operator's cab 13c (see Figure 1). The input unit 50 may be installed in a remote control device for remotely operating the work machine 10. The input unit 50 may be installed on an operation unit 51 (e.g., an operation lever) installed in the operator's cab 13c or the remote control device, or on the operation unit 51, or on a display (e.g., a cluster gauge). Unless otherwise specified, the detection unit 60, controller 70, and output unit 80 may be mounted on the work machine 10 or located outside the work machine 10. The input unit 50 includes an operation unit 51.

[0031] The control unit 51 is operated by a worker (operator) who operates the work machine 10. The control unit 51 receives input for operations to move the work machine 10. The control unit 51 outputs an operation signal in response to the input operations. The control unit 51 may be located in the driver's cab 13c (see Figure 1), or it may be located in a remote control device for remotely operating the work machine 10. For example, the control unit 51 may include a device (such as a key switch) for turning the battery 41 on and off (details will be described later). For example, the control unit 51 includes an actuator control unit 51a and an accelerator 51b.

[0032] The actuator operating unit 51a is an operating unit 51 for operating the actuator 30. The actuator operating unit 51a may be equipped with, for example, a lever (operating lever) or a pedal (operating pedal). The signal (command) that the actuator operating unit 51a outputs in response to operation is called the actuator operating signal (referred to as the "ACT operating signal" in Figure 2). The actuator operating signal may be, for example, a lever operating signal or a pedal operating signal.

[0033] The actuator control unit 51a may receive input for an operation to move the lower body 11 shown in Figure 1 (travel operation). The actuator control unit 51a (see Figure 2) may receive input for an operation to rotate the upper slewing body 13 relative to the lower body 11 (slewing operation). The actuator control unit 51a may receive input for an operation to move the attachment 15 (attachment operation). The actuator control unit 51a may receive input for an operation to rotate the boom 15a relative to the upper slewing body 13 (boom operation). The actuator control unit 51a may receive input for an operation to rotate the arm 15b relative to the boom 15a (arm operation). The actuator control unit 51a may receive input for an operation to rotate the tip attachment 15c relative to the arm 15b (tip attachment operation).

[0034] The accelerator 51b (pump rotation speed control unit) is an operating unit 51 for controlling the rotation speed of the pump 21 shown in Figure 2. The accelerator 51b controls the rotation speed of the pump 21 by controlling the rotation speed of the pump drive motor 45a. The accelerator 51b may be equipped with an operating dial, for example. The signal (command) output by the accelerator 51b in response to the operation is called the accelerator operation signal.

[0035] The detection unit 60 detects various states. For example, the detection unit 60 may detect the state of the work machine 10, or it may detect the state of the input of the input unit 50. For example, the detection unit 60 includes a battery state detection unit 61 and an operation detection unit 63.

[0036] The battery state detection unit 61 (battery state detection means) detects the state of the battery 41. The battery state detection unit 61 detects the charge rate (state of charge, SOC; State of Charge) of the battery 41. The charge rate is a value that indicates how much energy remains in the battery 41. The battery state detection unit 61 calculates the charge rate based on one or more pieces of information from the temperature, voltage, and current of the battery 41 (the calculation is included in the detection). The battery state detection unit 61 is mounted on the work machine 10. For example, the battery state detection unit 61 is a device mounted on the battery 41 (BMU; Battery Management Unit, BMS; Battery Management System).

[0037] The operation detection unit 63 (operation detection means) detects the amount of operation of the operation unit 51. The operation detection unit 63 may be provided inside the operator's cab 13c (see Figure 1), or it may be provided in a remote control device for remotely operating the work machine 10. The operation detection unit 63 may also detect the angle of the operation unit 51 (angle of lever, pedal, dial, etc.). The operation detection unit 63 may also detect commands output by the operation unit 51. For example, if the operation unit 51 outputs pilot hydraulic pressure corresponding to the amount of operation, the operation detection unit 63 may detect this pilot hydraulic pressure. Also, for example, if the operation unit 51 outputs an electrical signal corresponding to the amount of operation, the operation detection unit 63 may detect this electrical signal. In this case, the operation detection unit 63 may be the controller 70.

[0038] The controller 70 is a computer that performs signal input / output, calculations (processing), and information storage. The functions of the controller 70 are realized by the execution of a program stored in the storage unit 70b of the controller 70 by the calculation unit 70a. The controller 70 may be connected to other devices by wireless communication or by wired communication. The controller 70 may be distributed and arranged in multiple locations (it may constitute a distributed system). The components of the controller 70 may be connected to each other by wireless communication or by wired communication. For example, communication is performed by means of communication such as a mobile phone line, optical line, wireless LAN (Local Area Network), or wired LAN. For example, information is input to the controller 70 from the input unit 50 and the detection unit 60. For example, the controller 70 performs various processes, which will be described later. For example, when the work machine 10 is operated by automatic control, the controller 70 performs this automatic control. For example, the controller 70 outputs commands (signals) to move the work machine 10 to the hydraulic circuit 20 and the electrical circuit 40. For example, the controller 70 outputs information to the output unit 80. The controller 70 includes a calculation unit 70a and a storage unit 70b. Focusing on the functions of the controller 70, it includes a power management unit 71 and an electric motor control unit 73.

[0039] The arithmetic unit 70a performs calculations (processing) of information. The storage unit 70b stores the information.

[0040] The power management unit 71 (power management means) processes (manages) information related to the power supply. The power management unit 71 processes information related to the power supply of the electrical circuit 40. The power management unit 71 may also process information (information related to the power supply) of the auxiliary power supply circuit 46. The power management unit 71 is mounted on the work machine 10 (the same applies to the motor control unit 73).

[0041] The motor control unit 73 (motor control means) controls the operation of the motor 45. The motor control unit 73 controls the rotational speed of the motor 45. The motor control unit 73 controls the motor inverter 43. Specifically, the motor control unit 73 outputs a speed command for the motor 45 to the motor inverter 43, and controls the motor inverter 43 so that the motor 45 rotates at a speed corresponding to this speed command.

[0042] The output unit 80 (for example, a status display means) is a device that outputs information. The output unit 80 outputs information based on a signal output from the controller 70. The output unit 80 may output light (such as a display), sound (such as voice), or vibration. The output unit 80 may be provided in a tablet, a smartphone, or a personal computer. The output unit 80 may be provided in the driver's cab 13c (see Figure 1). The output unit 80 may be provided in a remote control device for remotely operating the work machine 10. If the output unit 80 outputs light, the output unit 80 may be equipped with a display device (monitor). The output unit 80 may be equipped with a light emitter (light). If the output unit 80 outputs sound, the output unit 80 may be equipped with a sound output device (speaker, buzzer, etc.). The output unit 80 may output information about the state of the battery 41, information about the power-on state and the power-off state, or, for example, information about the automatic power-off state described later.

[0043] (Operation) The power control device 1 is configured to operate as follows:

[0044] As described above, the work machine 10 shown in Figure 1 may be operated by an operator inside the operator's cab 13c (onboard operation), remotely operated by an operator from outside the work machine 10 (remote control device), or operated by automatic control. This automatic control may be semi-automatic operation (machine control, MC; machine control system) or automatic operation. The commands (operation commands, operation signals) for operating the work machine 10 may be commands corresponding to the operator's operation or commands from automatic control.

[0045] The following is a specific example of the operation of the work machine 10 when the work machine 10 is driven by the hydraulically operated actuator 30 (hydraulic actuator). The pump drive motor 45a shown in Figure 2 is driven (rotates) by the power of the battery 41. Specifically, for example, the motor control unit 73 outputs a command (e.g., motor speed command) to the motor inverter 43 in response to the command (actuator operation signal) for operating the operation unit 51 to move the work machine 10. The motor inverter 43 converts the DC current output by the battery 41 into AC current in response to the input command. The pump drive motor 45a is driven (rotates) by the AC current supplied from the motor inverter 43. The pump 21 is driven by the pump drive motor 45a and discharges hydraulic fluid. The hydraulically operated actuator 30 (hydraulic actuator) moves when hydraulic fluid (hydraulic energy) is supplied from the pump 21. As a result, the work machine 10 moves.

[0046] If the work machine 10 is equipped with an electric actuator 30 (an example of an electric motor 45 (e.g., a slewing motor 33)), this electric actuator 30 is driven (rotates) by the power of the battery 41 (details are the same as the drive of the pump drive motor 45a). The work machine 10 moves as the electric actuator 30 is driven.

[0047] As described above, the battery status detection unit 61 detects the charge level of the battery 41. The battery status detection unit 61 outputs (notifies) the detected charge level information to the controller 70 (for example, the power management unit 71). The operation detection unit 63 also detects the operation signal output by the operation unit 51 and outputs the detected information to the controller 70 (for example, the power management unit 71 and the motor control unit 73).

[0048] (Power on, Power off) The controller 70 (for example, the power management unit 71) can switch the state of whether or not power can be supplied from the battery 41 to the electric motor 45 (also called the "state of the battery 41") between a power-on state and a power-off state. The power-on state is a state in which power can be supplied from the battery 41 to the electric motor 45. Specifically, the state in which power is supplied from the battery 41 to the electric motor 45 and the electric motor 45 is running is the "power-on state". Even when power is not supplied from the battery 41 to the electric motor 45 and the electric motor 45 is not running, the state in which the electric motor 45 can be immediately driven in response to an operation performed by the operation unit 51 is the "power-on state". The power-off state is a state in which power cannot be supplied from the battery 41 to the electric motor 45. For example, the state in which the electric motor 45 does not drive even when an operation to drive the electric motor 45 is performed by the operation unit 51 is the "power-off state". In the following, switching from the power-on state to the power-off state will also be simply referred to as "power off." Similarly, switching from the power-off state to the power-on state will also be simply referred to as "power on." Switching between power on and power off may be performed by operating the control unit 51 (for example, by turning the key on or off using a key switch). Alternatively, power off may be performed automatically by the controller 70.

[0049] (Overview of power-off control) The controller 70 (more specifically, the power management unit 71 (hereinafter the same)) performs processing related to the state of the battery 41 depending on the situation. The controller 70 performs low charge power off processing P1 (see Figure 3), power off delay processing P2 (see Figure 5), power off delay release processing P3 (see Figure 5), inactivity power off processing P4 (see Figure 6), drive restriction processing P5 (see Figure 3), and notification processing P6 (see Figure 3).

[0050] (Low charge power off process P1) The low charge power-off process P1 (see Figure 3) is a process that turns off the power to the battery 41 when certain conditions are met, including the fact that the charge level of the battery 41 is less than or equal to the set charge rate SOC1 (see Figure 3) (the low charge power-off conditions described later).

[0051] The reason for performing this low-charge power-off process P1 (see Figure 3) is as follows: [Example of problem 1a] When battery 41 is over-discharged, battery 41 deteriorates and its lifespan is shortened. The charge level at which battery 41 deterioration becomes significant (e.g., 20% or less) is defined as the "over-discharge charge level". If the charge level of battery 41 is near the over-discharge charge level and higher than the over-discharge charge level (when battery 41 is in a low-charge state), and battery 41 remains powered on, the following problem occurs. In this case, if battery 41 supplies power to the electric motor 45, the charge level of battery 41 may decrease further, potentially leading to over-discharge of battery 41 (the charge level reaching the over-discharge charge level).

[0052] [Example of problem 1b] Furthermore, if the battery 41 supplies power to the auxiliary equipment 47, the following additional problem arises. In the case of work machinery 10 such as an excavator, it is frequently left unattended in a state in which the work machinery 10 can be operated (a state in which the actuator 30 can be operated in response to the operation of the actuator operating unit 51a). Also, for example, it is conceivable that the work machinery 10 may be left unattended (for example, for a long time) with the battery 41 powered on, due to forgetting to turn off the power. If the work machinery 10 is left unattended with the battery 41 powered on, the battery 41 will continue to supply power to the auxiliary equipment 47 (there will be power consumption of the auxiliary equipment 47). As a result, the charge level of the battery 41 will drop even further, and there is a risk that the battery 41 will be over-discharged (the charge level will reach the over-discharge charge level).

[0053] Therefore, when the low charge power-off condition is met, the controller 70 performs a low charge power-off process P1 (see Figure 3), which is a process that turns off the power to the battery 41. This prevents the battery 41 from being over-discharged. If the low charge power-off condition is not met, the controller 70 does not perform the low charge power-off process P1. In this case, the controller 70 leaves the battery 41 powered on.

[0054] (Low charge power off condition) The low-charge power-off condition includes the charge rate of the battery 41 detected by the battery state detection unit 61 (also called the charge rate detection value) being less than or equal to the charge rate setting value SOC1 (see Figure 3). The charge rate setting value SOC1 is set to a charge rate higher than the over-discharge charge rate (the charge rate at which battery 41 degradation becomes significant). The charge rate setting value SOC1 is set to a charge rate close to the over-discharge charge rate. The charge rate setting value SOC1 is set in the controller 70 in advance (before determining the low-charge power-off condition). The same applies to the various conditions described later, which are set in the controller 70 in advance (before determining the condition). The charge rate setting value SOC1 may also be a fixed value set in advance in the controller 70 (more specifically, in the memory unit 70b). The charge rate setting value SOC1 may also be set (manually set) by the operator operating the input unit 50. The controller 70 may automatically set the charge rate setting value SOC1 depending on the situation (for example, the detection result of the detection unit 60, the usage status of the battery 41, etc.). The same applies to the setting values ​​other than the charge rate setting value SOC1, as described below, which may be fixed values, manually set, or automatically set.

[0055] This low-charge power-off condition may include other conditions besides the charge rate detection value of the battery 41 being less than or equal to the charge rate set value SOC1 (see Figure 3). For example, the low-charge power-off condition may include conditions for the amount of operation of the actuator operating unit 51a (described later).

[0056] (Details of low charge power-off process P1) This low-charge power-off process P1 (see Figure 3) is a process that the controller 70 performs (automatically) when the low-charge power-off condition is met. The same applies to each of the following processes, which are processes that the controller 70 performs automatically when predetermined conditions are met. The low-charge power-off process P1 is a process that turns off the power to the battery 41. More specifically, the low-charge power-off process P1 is a process that switches the state of the battery 41 from the power-on state to the power-off state when the low-charge power-off condition is met. For example, when the low-charge power-off condition is met, the controller 70 turns off the power to the equipment that is powered by the battery 41 (executes the termination sequence). If the battery 41 can supply power to the auxiliary equipment 47, the controller 70 may also turn off the power to the auxiliary equipment 47 when the low-charge power-off condition is met. In this case, the controller 70 may output a signal (power-off signal) to the auxiliary equipment power supply circuit 46 to instruct it to turn off the power. For example, the controller 70 may turn off the power to a device that controls the operation of the battery 41 (an example of an auxiliary device 47) when the low charge power-off condition is met.

[0057] Furthermore, if an auxiliary battery 46b is provided, and the low charge power-off condition is met, the controller 70 may perform the following actions. In this case, the controller 70 may turn off the power to the battery 41 and also turn off the power to the auxiliary battery 46b (it may switch to a state where power cannot be supplied to the auxiliary 47). In this case, the controller 70 may also turn off the power to the auxiliary power circuit 46 (power to the auxiliary 47). In this case, the discharge of the auxiliary battery 46b is suppressed, and over-discharge of the auxiliary battery 46b is suppressed.

[0058] Furthermore, if an auxiliary battery 46b is provided, and the low charge power-off condition is met, the controller 70 may turn off the battery 41 but leave the auxiliary battery 46b powered on (in a state where it can supply power to the auxiliary 47). In this case, the controller 70 does not need to turn off the power to the auxiliary power circuit 46, nor does it need to turn off the power to some or all of the auxiliary 47. For example, if the auxiliary battery 46b supplies power to the output unit 80 and the low charge power-off condition is met, the controller 70 may leave the output unit 80 in a state where it can output information (described later).

[0059] When the controller 70 performs a low-charge power-off process P1 (see Figure 3), it stores information indicating that the low-charge power-off process P1 has been performed (power-off operation history signal, referred to as "history information" in Figure 2) in the storage unit 70b. The controller 70 also stores information indicating that the low-charge power-off process P1 has caused a switch from the power-on state to the power-off state in the storage unit 70b. The information indicating that the low-charge power-off process P1 has been performed is used in the power-off delay process P2 (see Figure 5), which will be described later.

[0060] (Low charge, no operation, power off process P1a) The low-charge power-off condition (the condition for performing the low-charge power-off process P1 (see Figure 3)) preferably includes an operation condition, which includes the condition that the actuator operating unit 51a is in an "unoperated state". The low-charge power-off condition that includes the operation condition is called the low-charge no-operation power-off condition. The low-charge power-off process P1 that the controller 70 performs when the low-power-receiving no-operation power-off condition is met is called the low-charge no-operation power-off process P1a (see Figure 4).

[0061] The reason why it is preferable for the low-charge power-off condition to include an "no operation" condition is as follows: If the conditions for the controller 70 to automatically power off the battery 41 include a charge level condition for the battery 41 but do not include an "no operation" condition, the following problems may occur. In this case, the battery 41 may be powered off while the actuator operating unit 51a is being operated, causing the actuator 30 to stop abruptly and the work machine 10 to stop abruptly (suddenly become immobile). This may cause a shock (shaking) to the work machine 10. In addition, the work machine 10 may stop in an obstructive location, in a location where it cannot be stably positioned, or in an unstable position (described later). Therefore, it is preferable for the low-charge power-off condition to include an "no operation" condition, which includes the condition that the actuator operating unit 51a is in an "unoperated state". In this case, the problem of the battery 41 being powered off while the actuator operating unit 51a is being operated and the work machine 10 suddenly stopping is suppressed.

[0062] (Low charge, no operation, power off condition) The low-charge, inactivity power-off conditions, as shown in Figure 4, include the detected charge rate of the battery 41 (see Figure 2) being less than or equal to the set charge rate SOC1, and the actuator 30 remaining in an "inactivity state" for a period of inactivity time T1 or longer (inactivity condition). In this case, the controller 70 shown in Figure 2 will not perform the low-charge, inactivity power-off process P1 (see Figure 4) even if the detected charge rate of the battery 41 is less than or equal to the set charge rate SOC1 (see Figure 4), unless the inactivity condition is met.

[0063] The above-mentioned "no-operation state" refers to a state in which no operation is performed to move the work machine 10. More specifically, the no-operation state refers to a state in which no operation (actuator operation) is performed to move the work machine 10 by the actuator operating unit 51a. The above-mentioned "operation to move the work machine 10" does not include the operation of the accelerator 51b. The no-operation state refers to a state in which no operation is performed to move the work machine 10 for any of the actuators 30 (for example, all of the boom cylinder 35a and arm cylinder 35b shown in Figure 1). Note that in the range of operation of the actuator operating unit 51a from zero to a certain small amount of operation (play range), the actuator 30 may not move. In this case, the state in which operation is performed only within this play range may be set as the no-operation state or as the operated state.

[0064] (Inactivity time setting value T1) The idle time setting value T1 (see Figure 4) is set in advance in the controller 70 (before determining the low charge idle power-off condition). The idle time setting value T1 may be a fixed value set in advance in the memory unit 70b, may be set manually, or may be set automatically in the controller 70. For example, the controller 70 may automatically set the idle time setting value T1 according to the detected charge rate of the battery 41. Specifically, the controller 70 may gradually or continuously shorten the idle time setting value T1 as the detected charge rate of the battery 41 decreases (the higher the possibility of over-discharge). For example, the idle time setting value T1 may be 0 seconds. For example, the idle time setting value T1 may be a time longer than 0 seconds. If the idle time setting value T1 is longer than 0 seconds, the battery 41 is prevented from being powered off the moment it becomes idle. Specifically, for example, the idle time setting value T1 could be the length of time during which the operator (worker) operating the work machine 10 is assumed to have no intention of operating the work machine 10.

[0065] (Power-off delay processing P2) The power-off delay process P2 (see Figure 5) is a process that delays the power-off of the battery 41 in the low-charge power-off process P1 when the power-off delay conditions (described later) are met.

[0066] The reasons for performing this power-off delay process P2 (see Figure 5) are as follows: After the battery 41 is powered off in the low-charge power-off process P1, it may be necessary to temporarily move the work machine 10. For example, it may be necessary to move (drive) the work machine 10 to a place (charging station) to charge the battery 41. Also, it may be necessary to move (emergency evacuation) the work machine 10 from a place where it is in the way (such as a place blocking a passageway or road) to a place where it is not in the way. Also, it may be necessary to move the work machine 10 from a place where it cannot be stably positioned (for example, a place with a steep slope) to a place where it can be stably positioned. Also, it may be necessary to change the posture of the work machine 10 from an unstable posture to a stable posture (for example, a parked posture where the tip attachment 15c (see Figure 1) is in contact with the ground).

[0067] It is conceivable that after the battery 41 is powered off by the low charge power-off process P1 (see Figure 5), the operator may operate the control unit 51 (e.g., a key switch) to temporarily operate the work machine 10, thereby powering on the battery 41. However, if the battery 41 is not charged to a level exceeding the charge rate set value SOC1 (see Figure 3) between the time it is powered off by the low charge power-off process P1 and the time it is powered on, the detected charge rate of the battery 41 will remain below the charge rate set value SOC1. In this case, the controller 70 will perform the low charge power-off process P1 (see Figure 3) immediately after the battery 41 is powered on, powering off the battery 41. Therefore, the work machine 10 cannot be operated. For example, it is conceivable that the power-on of the battery 41 in response to the operator's operation of the control unit 51 (e.g., manual operation of the key switch) and the power-off of the battery 41 by the controller 70's low charge power-off process P1 may occur repeatedly.

[0068] Therefore, when the power-off delay condition (described later) is met, the controller 70 performs a power-off delay process P2 (see Figure 5), which delays the power-off of the battery 41 in the low-charge power-off process P1 (see Figure 5). This process prevents the battery 41 from being powered off immediately after it is powered on following the low-charge power-off process P1. Thus, it becomes possible to operate the work machine 10.

[0069] (Power-off delay condition) The power-off delay condition includes the fact that the "previous power-off" (see below) was a power-off performed by the low-charge power-off process P1 (see Figure 5). More specifically, the power-off delay condition includes the fact that the most recent switch from the power-on state to the power-off state ("previous power-off"), relative to the power-on state, was a switch (power-off) performed by the low-charge power-off process P1. For example, if the "previous power-off" was performed by a process other than the low-charge power-off process P1 (e.g., manual operation of a key switch), the power-off delay condition is not met.

[0070] (Details of power-off delay processing P2) This power-off delay process P2 (see Figure 5) is a process that keeps the battery 41 powered on (maintains the powered-on state, does not power off) even when the low-charge power-off condition is met, until the delay termination condition (described later) is met. The power-off delay process P2 is a process that delays the timing of powering off the battery 41 until the delay termination condition is met, instead of immediately powering off the battery 41 when the low-charge power-off condition is met. The above "state in which the low-charge power-off condition is met" may be a state in which the controller 70 actually determines that the low-charge power-off condition has been met, or it may be a state in which the low-charge power-off condition would be met if the controller 70 made the determination. The controller 70 powers off the battery 41 when the low-charge power-off condition is met AND the delay termination condition is met.

[0071] A specific example of the process of delaying the timing of turning off the battery 41 in the power-off delay process P2 (see Figure 5) is as follows: The controller 70 may delay the timing of turning off the battery 41 by delaying the timing of determining the low charge power-off condition. Alternatively, the controller 70 does not have to delay the timing of determining the low charge power-off condition. For example, after determining that the low charge power-off condition has been met, the controller 70 may delay the timing of turning off the battery 41 by keeping the battery 41 powered on until the delay termination condition is met.

[0072] (Conditions for delayed termination) The delay termination condition is a condition in the power-off delay process P2 (see Figure 5) that causes the battery 41 to be powered off (terminating the power-off delay). The delay termination condition is set in advance in the controller 70 (before the delay termination condition is determined). The delay termination condition may include, for example, a time condition, or a condition for the detected charge level of the battery 41, or one or both of these conditions.

[0073] (Time delay termination condition (delay termination time setting value T2)) The delayed termination condition may include a time condition. For example, the delayed termination condition may include the elapsed time of the delayed termination time setting value T2 (see Figure 5) from the time the battery 41 was powered on (from the most recent power-on). If the power-off delay condition is met, the controller 70 may keep the battery 41 powered on until the delayed termination condition is met, which includes the elapsed time of the delayed termination time setting value T2 from the time the battery 41 was powered on.

[0074] The delayed termination time setting value T2 (see Figure 5) is set in advance in the controller 70 (before the delayed termination condition is determined). For example, if the idle time setting value T1 (see Figure 4) is set, the delayed termination time setting value T2 is longer than the idle time setting value T1. The delayed termination time setting value T2 may be a fixed value set in advance in the memory unit 70b, may be set manually, or may be set automatically in the controller 70 (the same applies to the delayed termination charge rate setting value below). For example, the controller 70 may gradually or continuously shorten the delayed termination time setting value T2 as the detected charge rate of the battery 41 decreases (the higher the possibility of over-discharge). For example, the delayed termination time setting value T2 may be set to the time that is expected to be required to temporarily operate the work machine 10 (e.g., 30 seconds, 1 minute, etc.).

[0075] (Conditions for delayed termination based on charge level detection) The delayed termination condition may include a condition for the detected charge level of the battery 41. For example, the delayed termination condition may include a decrease in the detected charge level of the battery 41 from the detected charge level when the battery 41 was powered on (most recent power-on) to a value equal to or greater than the delayed termination charge level setting. If the power-off delay condition is met, the controller 70 may keep the battery 41 powered on from the time the battery 41 was powered on until the delayed termination condition is met, which includes a decrease in the detected charge level of the battery 41 to a value equal to or greater than the delayed termination charge level setting.

[0076] The above delayed termination charge rate setting value is set in the controller 70 in advance (before the delayed termination condition is determined). For example, the controller 70 may gradually or continuously decrease the delayed termination charge rate setting value as the detected charge rate of the battery 41 (for example, the detected charge rate when the power was most recently turned on) decreases (the higher the likelihood of over-discharge). For example, the delayed termination charge rate setting value may be set to the amount of decrease in the detected charge rate (e.g., 1%, 2%, etc.) that corresponds to the amount of power expected to be needed to temporarily operate the work machine 10.

[0077] (Power-off delay release process P3) The power-off delay release process P3 (see Figure 5) is a process that releases (does not perform) the power-off delay release process P2 (see Figure 5) when the power-off delay release conditions (described later) are met.

[0078] The reason for performing this power-off delay release process P3 (see Figure 5) is as follows, for example. As described above, the power-off delay process P2 (see Figure 5) is a process that keeps the battery 41 in the power-on state until the delay termination condition is met, even when the low-charge power-off condition is met. As a result, the charge level of the battery 41 decreases, and there is a risk that the battery 41 will be over-discharged (the charge level will reach the over-discharge charge level). [Example of the problem 3a] For example, after the power is turned off by the low-charge power-off process P1, the battery 41 may be turned on without being charged to a charge level setting value SOC1 (see Figure 3), and this power-off and power-on cycle may be repeated frequently. Specifically, the operation to turn on the battery 41 (for example, turning on the key switch) may be repeated inadvertently. In that case, the charge level of the battery 41 may decrease, and there is a risk of over-discharge. [Example of problem 3b] If the low charge power off condition includes an operation condition (see Figure 4), even if the detected charge rate of the battery 41 is less than or equal to the charge rate set value SOC1, if actuator operation continues, the low charge power off process P1 will not be performed. As a result, the battery 41 will remain in the ON state, the charge rate of the battery 41 will decrease, and there is a risk that the battery 41 will be over-discharged.

[0079] Therefore, when the power-off delay release condition (described later) is met, the controller 70 performs a power-off delay release process P3 (see Figure 5), which releases the power-off delay process P2 (see Figure 5). By releasing the power-off delay process P2, over-discharge of the battery 41 is suppressed. If the power-off delay release condition is not met, the controller 70 does not perform the power-off delay release process P3.

[0080] (Conditions for releasing power-off delay) The power-off delay release conditions include conditions related to the likelihood of the battery 41 becoming over-discharged. Specifically, the power-off delay release conditions may include the following count conditions (see Figure 5), and may also include conditions related to the detected charge level of the battery 41.

[0081] (Conditions for releasing the power-off delay for the count count) The power-off delay release condition may include the fact that the count counted by the controller 70 (see Figure 5) is equal to or greater than the count setting value C3 (see Figure 5). If the power-off delay release condition, which includes the count being equal to or greater than the count setting value C3, is met, the controller 70 performs the power-off delay release process P3. If the count is less than the count setting value C3, the power-off delay release condition is not met, and the controller 70 does not perform the power-off delay release process P3. If the power-off delay condition is met AND the count is less than the count setting value C3, the controller 70 performs the power-off delay process P2.

[0082] The count (see Figure 5) is the number of consecutive times the low charge power off process P1 (see Figure 5) has been performed (number of repetitions, number of executions). Specifically, the controller 70 increments the count by 1 each time the low charge power off process P1 is performed. The controller 70 may reset the count to its initial value (e.g., 0) if certain conditions are met. For example, the controller 70 may reset the count to its initial value if the low charge power off condition is no longer met. Specifically, if the battery 41 is charged and the charge rate detection value exceeds the charge rate setting value SOC1 (see Figure 3), the controller 70 may reset the count to its initial value. The controller 70 counts the count based on information stored in the memory unit 70b (see Figure 2), for example. Specifically, for example, the controller 70 stores information on changes in the state of the battery 41 (history information) in the memory unit 70b. At this time, the controller 70 stores the reason for the power off (whether it was due to the low charge power off process P1, or due to operation of the operation unit 51, etc.) in the storage unit 70b. The controller 70 may also use the number of consecutive times the power off due to the low charge power off process P1 has occurred as the count.

[0083] The count setting value C3 (see Figure 5) is pre-set in the controller 70 (before determining the power-off delay release condition). The count setting value C3 is set based on, for example, the likelihood of the battery 41 being over-discharged. Specifically, the count setting value C3 may be 3, 4, or 5. If the count setting value C3 is too high, the power-off delay process P2 (see Figure 5) can be performed many times, increasing the likelihood of the battery 41 being over-discharged. On the other hand, if the count setting value C3 is too low, the number of times the power-off delay process P2 can be performed decreases, excessively limiting the number of times the work machine 10 can be temporarily operated. The count setting value C3 may be a fixed value pre-set in the memory unit 70b, may be manually set, or may be automatically set by the controller 70 according to some condition (the same applies to the charge rate setting value for delay release).

[0084] (Conditions for releasing the power-off delay during charging) The power-off delay release condition may include the charge level detection value of the battery 41 being less than or equal to a certain charge level (a set charge level for delay release). If the power-off delay release condition, which includes the charge level detection value of the battery 41 being less than or equal to the set charge level for delay release, is met, the controller 70 performs the power-off delay release process P3 (see Figure 5). If the charge level detection value of the battery 41 is higher than the set charge level for delay release, the power-off delay release condition is not met, and the controller 70 does not perform the power-off delay release process P3.

[0085] The above "Charge Rate Setting Value for Delay Release" is set in the controller 70 in advance (before determining the power-off delay release condition). The Charge Rate Setting Value for Delay Release is set to a value higher than the over-discharge charge rate (the charge rate at which battery 41 degradation becomes significant). The Charge Rate Setting Value for Delay Release is set to a value lower than the charge rate setting value SOC1 (see Figure 3) for the low-charge power-off process P1. The Charge Rate Setting Value for Delay Release is set based on factors such as the likelihood of battery 41 becoming over-discharged. If the Charge Rate Setting Value for Delay Release is too low, the power-off delay process P2 can be performed many times, increasing the likelihood of battery 41 becoming over-discharged. If the Charge Rate Setting Value for Delay Release is too high, the number of times the power-off delay process P2 can be performed decreases, excessively limiting the number of times the work machine 10 can be temporarily operated.

[0086] (Details of power-off delay release process P3) This power-off delay release process P3 (see Figure 5) is a process that performs the low-charge power-off process P1 (see Figure 5) without performing the power-off delay process P2 (see Figure 5), even if the power-off delay condition is met. Power-off delay release process P3 is a process that performs the low-charge power-off process P1 (see Figure 5) without performing the power-off delay process P2, even if the previous power-off was due to the low-charge power-off process P1 (see Figure 5). The "state in which the power-off delay condition is met" may be a state in which the controller 70 actually determines that the power-off delay condition has been met, or it may be a state in which the power-off delay condition would be met if the controller 70 made the determination.

[0087] (Power off process for inactivity P4) The idle power-off process P4 (see Figure 6) is a process that turns off the battery 41 when conditions (idle power-off conditions) are met, including the fact that the idle state has continued for an idle time setting value T1 or longer.

[0088] The reasons for performing the inactivity power-off process P4 (see Figure 6) are as follows: [Example of problem 4a] In the case of work machinery 10 such as an excavator, it is frequently the case that the work machinery 10 is left unattended while it is in a state where it can be operated (see [Example of problem 1b] above). Also, for example, it is conceivable that the work machinery 10 may be left unattended (for example, for a long time) with the battery 41 powered on, such as when the power is not turned off (see [Example of problem 1b] above). If the operator mistakenly perceives that the battery 41 is powered off and misoperates the actuator operating unit 51a, the actuator 30 may move against the operator's intention.

[0089] [Example of problem 4b] Furthermore, if the battery 41 supplies power to the auxiliary equipment 47, the following additional problem arises. If the work machine 10 is left idle, the battery 41 will continue to supply power to the auxiliary equipment 47 (the auxiliary equipment 47 will consume power). As a result, the charge level of the battery 41 will decrease, and there is a risk that the battery 41 will become over-discharged (the charge level will reach the over-discharge charge level).

[0090] Therefore, the controller 70 performs an idle power-off process P4 (see Figure 6), which turns off the battery 41, when a condition (idle power-off condition) is met, including the fact that the idle state has continued for an idle time setting value T1 (see Figure 6) or longer. This process suppresses the problem that occurs when the battery 41 remains powered on while the idle state continues for an idle time setting value T1 or longer (for example, when the work machine 10 is left unattended). The controller 70 does not perform the idle power-off process P4 if the idle power-off condition is not met.

[0091] (Condition: Power off due to lack of operation) The no-operation power-off condition includes the condition that the no-operation state continues for a no-operation time setting value T1 (see Figure 6) or longer (no-operation condition). The details of this no-operation condition are the same as the no-operation condition for the low-charge no-operation power-off process P1a (see Figure 4) described above. Note that the low-charge no-operation power-off condition for the low-charge no-operation power-off process P1a (see Figure 4) included the condition of the battery 41's charge rate detection value, but the no-operation power-off condition for the no-operation power-off process P4 (see Figure 6) does not include the condition of the battery 41's charge rate detection value. Furthermore, the controller 70 may be configured to execute both the low-charge no-operation power-off process P1a and the no-operation power-off process P4. In this case, the no-operation time setting value T1 (see Figure 4) in the low-charge no-operation power-off condition and the no-operation time setting value T1 (see Figure 6) in the no-operation power-off condition may be the same value or different values.

[0092] The details of the battery 41 power-off process in this idle power-off process P4 (see Figure 6) are the same as those of the battery 41 power-off process in the low-charge power-off process P1.

[0093] (Drive limiting process P5) The drive restriction process P5 (see Figure 3) is a process that restricts the driving of the electric motor 45 before the controller 70 turns off the battery 41. More specifically, the drive restriction process P5 is a process that restricts the driving of the electric motor 45 before the controller 70 automatically switches the state of the battery 41 from power-on to power-off. The controller 70 performs the drive restriction process P5 when the drive restriction conditions are met. The drive restriction conditions are set so that they are met before the controller 70 automatically switches the battery 41 off (specific examples will be described later).

[0094] The reason for performing this drive limiting process P5 (see Figure 3) is as follows: If the controller 70 automatically turns off the battery 41, the electric motor 45 will stop abruptly, the actuator 30 will stop abruptly, and the work machine 10 will stop abruptly (suddenly stop moving). Therefore, the controller 70 limits the drive of the electric motor 45 by the drive limiting process P5 before automatically turning off the battery 41. By limiting the drive of the electric motor 45, the operator is indirectly notified that the controller 70 will automatically turn off the battery 41. Note that this "operator" may be the operator of the work machine 10, an operator monitoring the work machine 10, or an operator in the vicinity of the work machine 10 (the same applies to "operator" below). In addition, by limiting the drive of the electric motor 45, the power consumption of the electric motor 45 is suppressed. Therefore, the decrease in the charge level of the battery 41 is suppressed, and over-discharge of the battery 41 is suppressed. The drive limiting process P5 includes an idle drive limiting process P5a (see Figures 4 and 6) and a low charge drive limiting process P5b (see Figures 3 and 4). Both the idle drive limiting process P5a and the low charge drive limiting process P5b may be performed (see Figure 4), or only one of them may be performed.

[0095] (Inactivity drive restriction process P5a) The no-operation drive restriction process P5a (see Figure 4) (rotation speed reduction process) is a drive restriction process P5 (see Figure 4) that is performed when the no-operation condition is met. The no-operation drive restriction process P5a is a drive restriction process P5 that is performed before the battery 41 is powered off by the low-charge no-operation power-off process P1a (see Figure 4) or the no-operation power-off process P4 (see Figure 6). The controller 70 performs the no-operation drive restriction process P5a when the following no-operation drive restriction condition (an example of a drive restriction condition) is met. The controller 70 does not perform the no-operation drive restriction process P5a if the no-operation drive restriction condition is not met.

[0096] (No-operation drive restriction condition) The no-operation drive restriction condition includes the fact that the no-operation state continues for a period of time equal to or longer than the no-operation time setting value T5a (see Figure 4). The no-operation time setting value T5a is set in advance in the controller 70 (before the no-operation drive restriction condition is determined). The no-operation time setting value T5a is set to a length less than the no-operation time setting value T1 (see Figure 4). When the no-operation drive restriction condition is met, including the fact that the time for which the no-operation state continues is equal to or longer than the no-operation time setting value T5a and less than the no-operation time setting value T1, the controller 70 performs the no-operation drive restriction process P5a (see Figure 4).

[0097] (Details of the idle drive restriction process P5a) The idle drive restriction process P5a (see Figure 4) is a process that restricts the driving of the electric motor 45. More specifically, the idle drive restriction process P5a (rotation speed reduction process) is a process that reduces the rotation speed of the pump drive motor 45a compared to before the idle drive restriction process P5a was performed. For example, the idle drive restriction process P5a is a process that sets the rotation speed of the pump drive motor 45a to a "low speed setting value". A specific example of the "low speed setting value" is as follows. Here, the range of rotation speeds of the pump drive motor 45a that can be set (changed) when the work machine 10 is performing normal work is called the "rotation speed range during work". The minimum value of this rotation speed range during work is called the "minimum rotation speed during work (low idle)".

[0098] [Example of low-speed setting value 1] Assume that the rotational speed of the pump drive motor 45a before the idle-drive restriction process P5a (see Figure 4) is performed is within the rotational speed range for work and higher than the minimum rotational speed for work (low idle). In this case, the controller 70 may set the rotational speed of the pump drive motor 45a to less than or equal to the minimum rotational speed for work (low idle) (an example of a "low-speed setting value") by the idle-drive restriction process P5a. [Example of low-speed setting value 2] The controller 70 may set the rotational speed of the pump drive motor 45a to greater than 0 and less than the minimum rotational speed for work (low idle) (an example of a "low-speed setting value") by the idle-drive restriction process P5a. In this case, the hydraulically operated actuator 30 (hydraulic actuator) can operate at a slower speed than during normal work. Therefore, the operator can be made aware that it is a situation in which normal work should not be performed. [Example of low-speed setting value 3] The controller 70 may set the rotation speed of the pump drive motor 45a to 0 (an example of a "low-speed setting value") by the idle drive limiting process P5a (it may also be stopped). In this case, the hydraulic actuator will not move (however, the battery 41 is powered on).

[0099] In the idle drive limiting process P5a (see Figure 4), the controller 70 may reduce the rotational speed of the pump drive motor 45a by one step or by multiple steps. For example, the idle time setting value T5a for drive limiting (see Figure 4) may be set in multiple steps. Each time the idle time reaches the idle time setting value T5a for drive limiting at each step, the controller 70 may reduce the rotational speed of the pump drive motor 45a in steps.

[0100] (Low charge operation limiting process P5b) The low-charge drive limiting process P5b (see Figure 3) is a drive limiting process P5 (see Figure 3) that is performed before the battery 41 is powered off by the low-charge power-off process P1 (see Figure 3). The controller 70 performs the low-charge drive limiting process P5b when the low-charge drive limiting conditions (an example of drive limiting conditions) are met.

[0101] (Low charge operation limit conditions) The low-charge drive limit condition includes the charge rate detection value of the battery 41 being less than or equal to the drive limit charge rate setting value SOC5b (see Figure 3). The controller 70 performs the low-charge drive limit process P5b when the low-charge drive limit condition, which includes the charge rate detection value of the battery 41 being less than or equal to the drive limit charge rate setting value SOC5b, is met. The drive limit charge rate setting value SOC5b is set in advance in the controller 70 (before the low-charge drive limit condition is determined). The drive limit charge rate setting value SOC5b may be a fixed value set in advance in the memory unit 70b, may be set manually, or may be set automatically by the controller 70 according to some condition. The drive limit charge rate setting value SOC5b is set to a value greater than the charge rate setting value SOC1.

[0102] (Details of low charge operation limiting process P5b) Low charge drive limiting process P5b (see Figure 3) is a process that limits the driving of the electric motor 45. [Example 1 of low charge drive limiting process P5b] For example, the low charge drive limiting process P5b may include a process that reduces the rotational speed of the pump drive motor 45a compared to before the low charge drive limiting process P5b is performed (similar to the no-operation drive limiting process P5a (see Figure 4)).

[0103] [Example 2 of Low Charge Drive Limit Processing P5b] Low charge drive limit processing P5b (see Figure 3) may include processing to limit the driving of the electric actuator 30 (electric motor 45 other than the pump drive motor 45a) in response to the operation of the actuator operating unit 51a. Specifically, during normal operation of the work machine 10, when the actuator operation amount is "a certain amount", the electric actuator 30 moves at "a certain operating speed". When low charge drive limit processing P5b is performed, the controller 70 may move the electric actuator 30 at an operating speed less than the "certain operating speed" when the actuator operation amount of "a certain amount" is performed.

[0104] (Notification process P6) Notification process P6 (see Figure 3) is a process that causes the output unit 80 to output information regarding the status of the battery 41 or the electric motor 45. The controller 70 performs notification process P6 when the notification conditions are met. The controller 70 does not perform notification process P6 when the notification conditions are not met. The output of the output unit 80 in notification process P6 may include a display, an audio signal, a vibration (e.g., vibration of the seat, control unit 51, etc.), or a combination of these.

[0105] For example, notification processing P6 includes automatic power-off notification processing P6a (see Figure 3) and drive limit notification processing P6b (see Figure 3).

[0106] (Automatic power-off notification process P6a) The automatic power-off notification process P6a (see Figure 3) is a process that notifies (outputs) the output unit 80 of the power-off (also called "automatic power-off") by the controller 70. Specifically, the automatic power-off may be, for example, a power-off by the low-charge power-off process P1 (see Figure 3) (including the low-charge no-operation power-off process P1a (see Figure 4)), or a power-off by the no-operation power-off process P4 (see Figure 6).

[0107] This automatic power-off notification process P6a is performed, and information regarding the automatic power-off is notified to the operator. Therefore, it is prevented for the operator from misunderstanding the status of the work machine 10. For example, it is prevented for the operator from mistakenly believing that the work machine 10 has stopped due to a malfunction.

[0108] This automatic power-off notification process P6a (see Figure 3) may be performed before the automatic power-off. This automatic power-off notification process P6a may be performed after the automatic power-off.

[0109] (Automatic power-off notification process P6a before automatic power-off) The automatic power-off notification process P6a (see Figure 3) may be performed before the automatic power-off. In this case, the operator can be notified of the automatic power-off before it occurs.

[0110] (Notification conditions before automatic power off) When the automatic power-off notification process P6a is performed before the automatic power-off, the notification conditions (timing of the output of the output unit 80) are as follows, for example. The notification conditions are set to be met before the automatic power-off.

[0111] The notification conditions may include time conditions. For example, the notification conditions may include being earlier by a notification setting time than the time when the controller 70 automatically powers off (scheduled time, predicted time, etc.). The notification setting time is set in the controller 70 in advance (before the notification conditions are determined). The notification setting time may be a fixed value set in advance in the storage unit 70b, may be set manually, or may be set automatically by the controller 70 in response to some condition.

[0112] The notification conditions may include conditions related to the charge level of the battery 41. For example, the notification conditions may include the detection value of the battery 41's charge level falling below a notification charge level setting value. The notification charge level setting value is greater than the charge level setting value SOC1 (see Figure 3). As a result, the detection value of the battery 41 reaches the notification charge level setting value before reaching the charge level setting value SOC1 (before automatic power off). For example, if a notification charge level setting value and a drive limit charge level setting value SOC5b are set, these settings may be the same value or may be different values ​​from each other.

[0113] (Details of the automatic power-off notification process P6a before automatic power-off) This automatic power-off notification process P6a (see Figure 3) is a process in which the controller 70 causes the output unit 80 to output information indicating that it is about to switch the state of the battery 41. The information that the controller 70 outputs to the output unit 80 in the automatic power-off notification process P6a, which is performed before the automatic power-off, is, for example, as follows: The automatic power-off notification information may include information indicating that an automatic power-off will be performed (such as a warning). The automatic power-off notification information may include information indicating when the automatic power-off will be performed. For example, the automatic power-off notification information may include information on the time from the present until the automatic power-off is performed (scheduled time, predicted time, etc.), and may also include information on the amount of decrease in the charge rate detection value from the present until the automatic power-off is performed. The automatic power-off notification information may include information indicating the reason (condition) for which the automatic power-off is about to be performed. For example, the automatic power-off notification information may include information indicating (warning) that the automatic power-off will be performed when the charge rate detection value of the battery 41 falls below the charge rate setting value SOC1 (see Figure 3). The automatic power-off notification information may include information indicating (warning) that the device will automatically power off if the period of inactivity continues for a period of time equal to or longer than the set value T1 (see Figure 4).

[0114] (Automatic power-off notification process after automatic power-off P6a) The automatic power-off notification process P6a (see Figure 3) may be performed after the automatic power-off occurs. Specifically, there are cases where the output unit 80 can output information after the battery 41 is powered off, such as when the auxiliary battery 46b can supply power to the output unit 80 after the battery 41 is powered off. In this case, the automatic power-off notification process P6a may be performed after the automatic power-off occurs. The automatic power-off notification process P6a may be performed during the execution of the automatic power-off process, or after the execution of the automatic power-off process. The automatic power-off notification information in the automatic power-off notification process P6a performed after the automatic power-off occurs may include information indicating that automatic power-off is being performed, or information indicating that automatic power-off has been performed. The automatic power-off notification information may include information indicating that automatic power-off is being performed or the reason (conditions) for doing so (see above for specific examples).

[0115] (Drive restriction notification process P6b) The drive limit notification process P6b (see Figure 3) is a process that notifies (outputs) the output unit 80 of the drive limit of the electric motor 45 by the controller 70. Specifically, this drive limit of the electric motor 45 is the drive limit in the drive limit process P5.

[0116] This drive limit notification process P6b (see Figure 3) is performed, and information regarding the drive limit is notified to the operator. Therefore, it is prevented for the operator from misunderstanding the status of the work machine 10. For example, it is prevented for the operator from misunderstanding that the work machine 10 has slowed down or stopped due to a malfunction in the work machine 10.

[0117] This drive limit notification process P6b (see Figure 3) may be performed before the drive limit is imposed. Specifically, when the drive limit notification process P6b is performed before the drive limit is imposed, the notification conditions (timing of the output of the output unit 80) are set to be met before the drive limit is imposed. These notification conditions may include time conditions or charge rate conditions (similar to the notification conditions for the automatic power off notification process P6a). Furthermore, the drive limit notification process P6b may be performed during the drive limit or after the drive limit is imposed.

[0118] The drive limit notification process P6b (see Figure 3) is a process in which the controller 70 outputs information regarding the drive limit of the electric motor 45 to the output unit 80. The information that the controller 70 outputs to the output unit 80 in the drive limit notification process P6b, which is performed before the drive limit is imposed (drive limit notification information), is, for example, as follows: The drive limit notification information may include information indicating that the drive limit will be imposed (such as a warning). The drive limit notification information may include information indicating when the drive limit will be imposed. For example, the drive limit notification information may include information on the time from the present until the drive limit is imposed (scheduled time, predicted time, etc.), and may also include information on the amount of decrease in the detected charge rate of the battery 41 from the present until the drive limit is imposed. The drive limit notification information may include information indicating the reason (condition) for imposing the drive limit. For example, the drive limit notification information may include information indicating that the drive limit will be imposed when the detected charge rate of the battery 41 falls below the drive limit charge rate setting value SOC5b (see Figure 3). The drive restriction notification information may include information indicating that drive restriction will be initiated if the idle time continues for a period equal to or longer than the drive restriction idle time setting value T5a (see Figure 4).

[0119] The drive restriction notification information in the drive restriction notification process P6b (see Figure 3) performed after the drive restriction is applied may be as follows: The drive restriction notification information may include information indicating that a drive restriction is being applied, or information indicating that a drive restriction has been applied. The drive restriction notification information may also include information indicating that a drive restriction is being applied or the reason (condition) for applying the drive restriction (see above for specific examples).

[0120] (Specific example of processing by controller 70) Referring to the flowcharts shown in Figures 7 and 8, a specific example of the processing of the controller 70 shown in Figure 2 will be explained. Unless otherwise specified, the explanation will follow the order of processing. Note that the order of processing can be changed in various ways.

[0121] (Processes such as idle drive restriction processing P5a and idle power off processing P4) Referring to the flowchart in Figure 7, the processes performed by the controller 70 shown in Figure 2, such as the idle drive limiting process P5a (see Figure 6) and the idle power off process P4 (see Figure 6), will be explained. In the following, each step (S11 to S32) shown in Figure 7 will be explained with reference to Figure 7.

[0122] In step S11, the controller 70 reads the operation information (operation signal) detected by the operation detection unit 63. Specifically, the controller 70 reads the operation signal from the actuator operation unit 51a (actuator operation signal (ACT operation signal in Figure 7)) and the operation signal from the accelerator 51b (accelerator operation signal).

[0123] In step S12, the controller 70 determines whether or not the system is in an idle state. Specifically, the controller 70 determines whether or not there is an actuator operation signal. If no actuator operation signal is input, the controller 70 determines that the system is in an idle state, and if an actuator operation signal is input, it determines that the system is not in an idle state. If the controller 70 determines that the system is in an idle state (YES in step S12), it increments the timer (step S13) and performs the process in step S21. This "timer" is a value that indicates the duration of the idle state. If the controller 70 determines that the system is not in an idle state (NO in step S12), it sets the timer to its initial value (e.g., 0) (reset) (step S14) and performs the process in step S21.

[0124] In step S21, the controller 70 determines whether the idle state has continued for longer than the set value T5a for drive limiting idle time (see Figure 6) (in Figure 7, "set value T5a"). Specifically, the controller 70 determines whether the value of the timer (step S13) is greater than or equal to the set value T5a for drive limiting idle time. If the controller 70 determines that the idle state has continued for longer than the set value T5a for drive limiting idle time (if YES in step S21), it performs the process in step S22. If the controller 70 determines that the idle state has not continued for longer than the set value T5a for drive limiting idle time (if NO in step S21), it performs the process in step S23.

[0125] In step S22, the controller 70 performs the no-operation drive restriction process P5a if the no-operation state continues for longer than the no-operation time setting value T5a for drive restriction (if the answer in step S21 is YES), thereby restricting the operation of the electric motor 45. For example, the controller 70 sets the rotational speed command (motor speed command) of the electric motor 45 (specifically the pump drive motor 45a) to the "low speed setting value" (see the explanation of the no-operation drive restriction process P5a for details). Then, the controller 70 performs the process in step S31.

[0126] In step S23, the controller 70 does not restrict the operation of the motor 45 if the idle state does not continue for longer than the idle time setting value T5a for drive restriction (if the answer in step S21 is NO). For example, the controller 70 sets the command for the rotational speed of the motor 45 (specifically, the pump drive motor 45a) (motor speed command) to the value of the accelerator operation signal (accelerator value). Then, the controller 70 performs the process in step S31.

[0127] In step S31, the controller 70 determines whether the inactivity state has continued for longer than the inactivity time setting value T1 (see Figure 6) (in Figure 7, "setting value T1"). Specifically, the controller 70 determines whether the value of the timer (step S13) is greater than or equal to the inactivity time setting value T1. If the inactivity state does not continue for longer than the inactivity time setting value T1 (if NO in step S31), the controller 70 does not perform the process of turning off the battery 41 (step S32) and leaves the battery 41 powered on. Then, the controller 70 performs the process in step S11 (the processing flow returns to the start). If the inactivity state continues for longer than the inactivity time setting value T1 (if YES in step S31), the controller 70 performs the process in step S32.

[0128] In step S32, the controller 70 performs an inactivity power-off process P4 (see Figure 6) and turns off the battery 41 (for example, by executing a termination sequence).

[0129] (Processes such as low charge power off processing P1, low charge no operation power off processing P1a, etc.) Referring to the flowchart in Figure 8, the processes performed by the controller 70, such as the low-charge, inactivity power-off process P1a (see Figure 4) and the power-off delay process P2 (see Figure 5), will be explained. In the following, each step (S41 to S63) shown in Figure 8 will be explained with reference to Figure 8.

[0130] In step S41, the controller 70 shown in Figure 2 reads the count (see Figure 5). The count is the number of times the low charge power off process P1 (see Figure 5) has been performed consecutively (see above for details).

[0131] In step S42, the controller 70 determines whether the low-charge power-off condition is met. Specifically, the controller 70 determines whether the detected charge rate of the battery 41 is less than or equal to the set charge rate SOC1 (see Figure 4). If the detected charge rate of the battery 41 is less than or equal to the set charge rate SOC1, the controller 70 determines that the low-charge power-off condition is met. If the detected charge rate of the battery 41 exceeds the set charge rate SOC1, the controller 70 determines that the low-charge power-off condition is not met. If the controller 70 determines that the low-charge power-off condition is met (YES in step S42), it performs the process in step S43. If the controller 70 determines that the low-charge power-off condition is not met (NO in step S42), it performs the process in step S41 (the processing flow returns to the start).

[0132] In step S43, the controller 70 determines whether the power-off delay condition is met and whether the power-off delay release condition is met. Specifically, the controller 70 determines whether the power-off delay condition is met by determining whether the count (see step S41) is greater than 0, that is, whether the previous power-off was due to the low-charge power-off process P1 (see Figure 5). The controller 70 also determines whether the power-off delay release condition is met by determining whether the count is greater than or equal to the count setting value C3. If the count is greater than 0, the controller 70 determines that the power-off delay condition is met. If the count is greater than or equal to the count setting value C3, the controller 70 determines that the power-off delay release condition is met. If the controller 70 determines that the power-off delay condition is not met, or that the power-off delay release condition is met (if the result in step S43 is NO), it performs the process in step S45.

[0133] In step S44, if the controller 70 determines that the power-off delay condition is met and the power-off delay release condition is not met (if the answer in step S43 is YES), it performs the power-off delay process P2 (see Figure 5). Specifically, the controller 70 sets the timer determination value (reference value, threshold) used in the determination in step S61 to the delay end time setting value T2 (see Figure 5) (delay setting value). Then, the controller 70 performs the process in step S51.

[0134] In step S45, if the controller 70 determines that the power-off delay condition is not met, or that the power-off delay release condition is met (if the answer in S43 is NO), it does not perform the power-off delay process P2 (see Figure 5). In this case, the controller 70 sets the timer determination value used in the determination in step S61 to the idle time setting value T1 (see Figure 4) (no delay setting value). Then, the controller 70 performs the process in step S51.

[0135] In step S51, the controller 70 reads the operation information (operation signal) detected by the operation detection unit 63. In the example shown in Figure 8, the controller 70 reads the actuator operation signal (ACT operation signal in Figure 8). The controller 70 shown in Figure 2 may also read the accelerator operation signal (similar to step S11 in Figure 7).

[0136] In step S52, the controller 70 determines whether or not there is no operation (similar to step S12 in Figure 7). If the controller 70 determines that there is no operation (for example, if there is an actuator operation signal) (if YES in step S52), it counts up the timer (step S53) (similar to step S13 in Figure 7) and performs the process in step S61. If the controller 70 determines that there is no operation (for example, if there is no actuator operation signal) (if NO in step S52), it resets the timer (step S53) (similar to step S14 in Figure 7) and performs the process in step S61.

[0137] In step S61, the controller 70 determines whether the inactivity state has continued for longer than the timer determination value (reference value, threshold). Specifically, if the controller 70 determines that the power-off delay condition is met and the power-off delay release condition is not met (if YES in step S43), it determines whether the inactivity state has continued for longer than the delay end time setting value T2 (setting value with delay). If the controller 70 determines that the power-off delay condition is not met or the power-off delay release condition is met (if NO in step S43), it determines whether the inactivity state has continued for longer than the inactivity time setting value T1 (setting value without delay). Specifically, the controller 70 determines whether the timer value is equal to or greater than the timer determination value set in step S44 or step S45. If the controller 70 determines that the inactivity state has not continued for longer than the timer determination value (if NO in step S61), it performs the process in step S41 without performing the process of turning off the battery 41 (step S63) (the flow returns to start). If the controller 70 determines that the inactivity state continues for a period longer than the timer determination value (if YES is obtained in step S61), it performs the process in step S62.

[0138] In step S62, the controller 70 increments the count by 1. The controller 70 stores the incremented count in the storage unit 70b.

[0139] In step S63, the controller 70 powers off the battery 41 by performing a low charge / no operation power-off process P1a (see Figure 4) (for example, by executing a termination sequence).

[0140] The controller 70 may also perform processes not shown in Figures 7 and 8 (for example, the drive restriction process P5 and notification process P6 shown in Figure 4). Specifically, for example, the controller 70 shown in Figure 2 may, in step S61 (see Figure 8), determine whether the timer value is equal to or greater than the drive restriction idle time setting value T5a (see Figure 4). If the conditions including the timer value being equal to or greater than the drive restriction idle time setting value T5a (idle drive restriction condition) are met, the controller 70 may perform the idle drive restriction process P5a (see Figure 4). Also, for example, the controller 70 may perform the notification process P6 if it determines that the notification condition is met.

[0141] (Effects of the first invention) The effects of the power control device 1 shown in Figure 2 are as follows. The power control device 1 comprises a battery 41, a battery state detection unit 61, and a controller 70. The battery 41 supplies power to the electric motor 45 that operates the work machine 10 (see Figure 1). The battery state detection unit 61 detects the charge level of the battery 41. The controller 70 can be switched between a power-on state and a power-off state. The power-on state is a state in which power can be supplied from the battery 41 to the electric motor 45. The power-off state is a state in which power cannot be supplied from the battery 41 to the electric motor 45.

[0142] [Configuration 1-1] The controller 70 performs a low-charge power-off process P1 (see Figure 3) when the low-charge power-off condition is met. The low-charge power-off condition includes the condition that the charge rate of the battery 41 detected by the battery state detection unit 61 (charge rate detection value) is less than or equal to the charge rate setting value SOC1 (see Figure 3) set in the controller 70. The low-charge power-off process P1 is a process that switches the state of the battery 41 from the power-on state to the power-off state (turns the power off).

[0143] [Configuration 1-2] When the power-off delay condition is met, the controller 70 performs a power-off delay process P2 (see Figure 5). The power-off delay condition is a condition in which the most recent switch from the power-on state to the power-off state (previous power-off), relative to the power-on state, was a switch (power-off) by the low-charge power-off process P1 (see Figure 5). The power-off delay process P2 is a process that keeps the battery 41 in the power-on state even when the low-charge power-off condition is met, until the delay termination condition (for example, the delay termination time setting value T2 (see Figure 5)) set in the controller 70 is met.

[0144] In the above configuration [1-1], the controller 70 turns off the power to the battery 41 when conditions are met, including the fact that the detected charge rate of the battery 41 is less than or equal to the set charge rate SOC1 (see Figure 3) (i.e., it is in a low-charge state). Therefore, it is possible to suppress further decrease in the charge rate of the battery 41. Therefore, it is possible to suppress over-discharge of the battery 41.

[0145] Here, if the battery 41 is turned off by the low-charge power-off process P1 (see Figure 3), and then turned on before the battery 41 is sufficiently charged, the low-charge power-off condition may be met, and the battery 41 may be turned off again. In this case, the battery 41 cannot supply power to the electric motor 45, and therefore the work machine 10 cannot be operated. So the controller 70 performs the power-off delay process P2 (see Figure 5) described in [Configuration 1-2] above. Therefore, if the power-off delay condition is met, including the fact that the previous power-off was due to the low-charge power-off process P1 (see Figure 5), the state of the battery 41 remains powered on until the delay termination condition is met, even if the low-charge power-off condition is met. Therefore, the battery 41 can supply power to the electric motor 45, and the work machine 10 can be operated. Thus, the power control device 1 can suppress over-discharge of the battery 41 by [Configuration 1-1] and [Configuration 1-2] above, and can operate the work machine 10 until a predetermined condition (delay termination condition) is met.

[0146] (Effects of the second invention) [Configuration 2] The delayed termination condition (see [Configuration 1-2] above) includes the time when the state of the battery 41 switches from the power-off state to the power-on state (when the power is turned on) and when the delayed termination time setting value T2 (see Figure 5) has elapsed. The delayed termination time setting value T2 is the value set in the controller 70.

[0147] In the above [Configuration 2], the delayed termination condition includes a time condition, which is the delayed termination time setting value T2 (see Figure 5). Therefore, compared to cases where the delayed termination condition does not include a time condition (for example, cases where it only includes the charge level of the battery 41), it is possible to easily understand when the battery 41 will be powered off (when the delayed termination condition will be met).

[0148] (Effects of the third invention) [Configuration 3] The low charge power-off condition includes a state of inactivity that continues for a period of time equal to or longer than the inactivity time setting value T1 (see Figure 4). Inactivity means that no operation is being performed to move the work machine 10. The inactivity time setting value T1 is the time set in the controller 70.

[0149] The above [Configuration 3] provides the following effects. For example, if the low charge power-off condition does not include the condition of being inactive, the battery 41 may become low charge while the work machine 10 is being operated, and the low charge power-off process P1 (see Figure 4) may turn off the battery 41. In this case, the battery 41 will suddenly turn off, and the movement of the electric motor 45 will stop abruptly. This may cause, for example, a shock (shaking) to the work machine 10. Also, if the battery 41 suddenly turns off, the work machine 10 may stop in an inappropriate location or position, and the work machine 10 may stop while it is in a state where movement or a change in position is required. Therefore, in the above [Configuration 3], the low charge power-off condition includes the state of being inactive for a period of time set to no operation T1 (see Figure 4) or longer. Thus, it is possible to suppress the work machine 10 from stopping while the work machine 10 is being operated.

[0150] (Effects of the fourth invention) [Configuration 4] The controller 70 performs an inactivity power-off process P4 (see Figure 6) when the inactivity power-off condition is met. The inactivity power-off condition is a condition that includes the fact that the inactivity state has continued for an inactivity time setting value T1 (see Figure 6) or longer. The inactivity state is a state in which no operation is performed to move the work machine 10. The inactivity time setting value T1 is the time set in the controller 70. The inactivity power-off process P4 is a process that switches the state of the battery 41 from the power-on state to the power-off state.

[0151] In the above configuration [4], when the no-operation power-off condition is met, which includes the condition that the no-operation state continues for a no-operation time set value T1 (see Figure 6), the battery 41 is powered off by the no-operation power-off process P4 (see Figure 6). Therefore, over-discharge of the battery 41 can be suppressed.

[0152] (Effects of the fifth invention) [Configuration 5] The controller 70 restricts the driving of the electric motor 45 when the drive restriction condition is met (see drive restriction process P5 in Figure 4). The drive restriction condition is set to be met before the battery 41 state is automatically switched from the power-on state to the power-off state (before automatic power-off).

[0153] As described in [Configuration 5] above, the operation of the electric motor 45 is restricted, which indirectly allows the operator (operator, surrounding workers, etc.) to recognize that the controller 70 will automatically turn off the battery 41. In addition, by restricting the operation of the electric motor 45, power consumption by the electric motor 45 is suppressed. Therefore, over-discharge of the battery 41 can be suppressed.

[0154] (Effects of the sixth invention) [Configuration 6] The power control device 1 includes an output unit 80 that outputs information. When the notification condition (notification condition before automatic power off) is met, the controller 70 causes the output unit 80 to output information indicating that it is about to switch the state of the battery 41 (see notification process P6 in Figure 4). The notification condition (notification condition before automatic power off) is set to be met before the state of the battery 41 is automatically switched from the power-on state to the power-off state (before automatic power off).

[0155] As described in [Configuration 6] above, the controller 70 can be made aware to the operator (operator, surrounding workers) that it will automatically turn off the battery 41. As a result, it is possible to prevent the operator from misunderstanding the status of the work machine 10, for example, by mistakenly believing that the work machine 10 has stopped due to a malfunction.

[0156] (Effects of the seventh invention) [Configuration 7] The controller 70 counts the count (see Figure 5). The count is the number of times the low charge power off process P1 (see Figure 5) has been performed consecutively. If the count is equal to or greater than the count setting value C3 (see Figure 5) set in the controller 70, the controller 70 performs the power off delay release process P3 (see Figure 5). The power off delay release process P3 is a process that performs the low charge power off process P1 without performing the power off delay process P2 (see Figure 5) even when the power off delay condition is met.

[0157] The above [Configuration 7] provides the following effect. In the power-off delay process P2 (see Figure 5), even when the low-charge power-off condition is met, the state of the battery 41 is kept in the power-on state until the delay termination condition is met (see [Configuration 1-2] above). At this time, since the battery 41 is in the power-on state, the charge level of the battery 41 decreases further from the state where the low-charge power-off condition is met (low-charge state). Therefore, if the power-on state due to the power-off delay process P2 continues for a long time, or if the delay in the power-off delay process P2 is performed many times, there is a risk that the battery 41 will be over-discharged. Therefore, in the above [Configuration 7], the controller 70 performs the power-off delay release process P3 (see Figure 5) when the count (see Figure 5) is equal to or greater than the count setting value C3 (see Figure 5). Thus, the controller 70 limits the number of times the power-off delay process P2 (see Figure 5) is performed. Thus, it is possible to suppress the over-discharge of the battery 41.

[0158] (modified version) The above embodiments (including modifications within the embodiments (hereinafter the same)) may be modified in various ways. For example, the number of components in the above embodiments may be changed, and some components may not be provided. For example, the arrangement of components may be changed. For example, the fixing or connection of components may be direct or indirect. For example, the connections between components shown in Figure 2, etc., may be changed. For example, the inclusion relationships of components may be changed in various ways. For example, a component described as a subordinate component included in a higher-level component may not be included in this higher-level component, but may be included in other components. For example, what was described as multiple distinct elements may be treated as a single element. For example, what was described as a single element may be divided into multiple distinct elements. For example, each component may have only a part of each characteristic (function, arrangement, shape, operation, etc.).

[0159] For example, the order of steps in the flowcharts shown in Figures 7 and 8 may be changed, some steps may be omitted, and steps from different flowcharts may be combined. For example, various types of information (values, ranges, etc.) may be pre-set in the controller 70 shown in Figure 2, or they may be set by being read into the controller 70 from an external storage device. Various types of information may be set in the controller 70 based on information set by manual operation by an operator. Various types of information may be set in the controller 70 based on information detected by the detection unit 60. For example, various types of information may not be changed, may be changed by manual operation, or may be automatically changed by the controller 70 according to some condition. For example, the controller 70 may perform substantially the same processing as the processing (calculation, judgment, etc.) of the above embodiment. For example, the processing procedure, the information used in the processing, etc. can be changed in various ways. Specifically, the controller 70 may perform processing using information that can be converted into the various types of information used in the above embodiment. The processing performed by the controller 70 may be combined in various ways.

[0160] The power control device 1 is configured to perform each of the operations described above. A power control program may be set to cause a computer (controller 70) to perform the processes that cause each of the operations described above. A power control method may be performed to perform each of the operations described above. Each of the operations described above may be referred to as a "step" in the power control program and power control method described above. For example, the low charge power off process P1 may be referred to as the "low charge power off step". [Explanation of Symbols]

[0161] 1 Power supply control device 10 Working Machines 41 batteries 45 Electric motor 61 Battery status detection unit 70 Controllers 80 Output section C3 Count setting value P1 Low charge power off process P2 Power Off Delay Processing P3 Power Off Delay Release Process P4 Power off process for inactivity P5 Drive Limit Processing P6 Notification Processing SOC1 charge level setting T1 Idle time setting T2 Delayed End Time Setting

Claims

1. A battery that supplies power to the electric motor that operates the work machine, A battery state detection unit for detecting the charge level of the aforementioned battery, Controller and Equipped with, The aforementioned controller, A power-on state in which power can be supplied from the battery to the electric motor, A power-off state in which power cannot be supplied from the battery to the motor, It can be switched to, The controller performs a low-charge power-off process to switch the battery state from the power-on state to the power-off state when a low-charge power-off condition is met, which includes the condition that the charge level of the battery detected by the battery state detection unit is less than or equal to the charge level setting value set in the controller. The controller performs a power-off delay process when the power-off delay condition is met, which includes the condition that the most recent switch from the power-on state to the power-off state, relative to the power-on state, was a switch due to the low-charge power-off process. The aforementioned power-off delay process is a process that maintains the battery state in the power-on state even when the low-charge power-off condition is met, until the delay termination condition, which is a condition set in the controller, is met. Power supply control device.

2. A power control device according to claim 1, The aforementioned delay termination condition includes the time elapsed from the time the battery state switches from the power-off state to the power-on state to the time the delay termination time setting value, which is set in the controller, is set. Power supply control device.

3. A power control device according to claim 1, The low-charge power-off condition includes a state in which no operation is performed to move the work machine, and this state continues for a period of time equal to or longer than the inactivity time setting value set in the controller. Power supply control device.

4. A power control device according to claim 1, The aforementioned controller, When the no-operation power-off condition is met, which includes the condition that the no-operation state, in which no operation is performed to move the aforementioned work machine, continues for a period of time equal to or longer than the no-operation time setting value set in the controller, The system performs an inactivity power-off process to switch the state of the battery from the power-on state to the power-off state. Power supply control device.

5. A power control device according to any one of claims 1 to 4, The controller restricts the operation of the electric motor when a drive limiting condition, which is set to be met before the battery state is automatically switched from the power-on state to the power-off state, is met. Power supply control device.

6. A power control device according to any one of claims 1 to 4, It is equipped with an output unit that outputs information, The controller causes the output unit to output information indicating that it is attempting to switch the battery state when a notification condition set to be met before the battery state is automatically switched from the power-on state to the power-off state is met. Power supply control device.

7. A power control device according to claim 1, The controller counts a number which is the number of consecutive times the low charge power-off process has been performed. If the count is equal to or greater than the count setting value set in the controller, the controller performs a power off delay release process. The power-off delay release process is a process that performs the low-charge power-off process without performing the power-off delay process, even when the power-off delay condition is met. Power supply control device.

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