Electric work machine and method for controlling electric work machine

Abstract

Provided is an electric work machine that achieves both shortening of charging time and suppression of rise of battery temperature according to use.　An electric work machine (1) comprises: a battery unit (30); an electric actuator (9) that operates with electric power supplied by the battery unit; a work device (20) that operates by driving the electric actuator; temperature detection devices (31b, 31c, 31d, 32b, 32c, 32d) that detect the temperature of the battery unit; and a control device (7) that controls a first upper limit value (I_th1) which is an upper limit value of the charging current supplied to the battery unit according to the temperature of the battery unit. The control device can switch between a first mode (M1) in which the charging current is controlled on the basis of a first correspondence relationship in which the temperature of the battery unit and the first upper limit value are associated with each other, and a second mode (M2) in which the charging current is controlled on the basis of a second correspondence relationship in which the first upper limit value corresponding to at least a partial temperature is lower than the first correspondence relationship.

Description

Electric work machine and control method for electric work machine

[0001] The present invention relates to an electric working machine that operates on power from a battery unit and a method for controlling the electric working machine.

[0002] The electric work machine disclosed in Patent Document 1 includes an electric motor, a battery unit that supplies power to the electric motor, a hydraulic pump that is driven by the electric motor and discharges hydraulic oil, hydraulic equipment that is driven by the hydraulic oil, and a work device that is operated by the hydraulic equipment. In such an electric work machine, when the remaining charge of the battery unit becomes low, quick charging is sometimes performed using an externally installed charger.

[0003] Japanese Patent Publication No. 2021-80703

[0004] However, the battery unit generates heat during both charging and discharging, and the risk of deterioration increases when the temperature becomes too high. In particular, when a battery unit is rapidly charged using a rapid charger, a large current (e.g., up to approximately 125 amperes) flows through the battery unit, allowing charging to be completed in a relatively short time, but causing a significant increase in the temperature of the battery unit. Furthermore, in the case of a work machine equipped with a function that restricts operation when the temperature of the battery unit exceeds a predetermined value, even if charging itself can be completed in a relatively short time using rapid charging, operation may be restricted until the temperature of the battery unit drops.

[0005] The present invention has been made to solve the problems of the conventional technology, and aims to achieve both a reduction in charging time and suppression of battery temperature increases in electric work machines depending on the application.

[0006] An electric work machine according to one embodiment of the present invention comprises a battery unit, an electric actuator operated by power supplied by the battery unit, a work device operated by driving the electric actuator, a temperature detection device that detects the temperature of the battery unit, and a control device that controls a first upper limit value, which is an upper limit value of the charging current supplied to the battery unit, in accordance with the temperature of the battery unit, and the control device is switchable between a first mode in which the charging current is controlled based on a first correspondence relationship that corresponds the temperature of the battery unit to the first upper limit value, and a second mode in which the charging current is controlled based on a second correspondence relationship in which the first upper limit value corresponding to at least some temperatures is lower than the first correspondence relationship.

[0007] The control device may be configured to lower the first upper limit value as the temperature of the battery unit increases in each of the first mode and the second mode.

[0008] The first upper limit value of the second mode in a predetermined first temperature range of the temperature of the battery unit may be lower than the first upper limit value of the first mode in the first temperature range, and the first upper limit value of the second mode in a second temperature range in which the temperature of the battery unit is higher than in the first temperature range may be approximately equal to the first upper limit value of the first mode in the second temperature range.

[0009] In at least one of the first mode and the second mode, the first upper limit value of the first temperature zone may be constant with respect to the temperature of the battery unit.

[0010] The control device may control an output of the work device in accordance with a temperature of the battery unit.

[0011] The control device may control a second upper limit value, which is an upper limit value of a discharge current supplied from the battery unit to the electric actuator, in accordance with the temperature of the battery unit.

[0012] The control device may lower the second upper limit value as the temperature of the battery unit increases.

[0013] The device may include a switch for switching between the first mode and the second mode.

[0014] A control method for an electric work machine according to one aspect of the present invention is a control method for an electric work machine including a battery unit, an electric actuator operated by power supplied by the battery unit, a work device operated by driving the electric actuator, a temperature detection device that detects the temperature of the battery unit, and a control device that controls charging of the battery unit, the control method including a first step of selecting either a first mode or a second mode, and a second step of controlling a first upper limit value that is an upper limit value of a charging current supplied to the battery unit depending on the mode selected in the first step and the temperature of the battery unit, wherein in the second step, if the first mode is selected, the charging current is controlled based on a first correspondence relationship that corresponds the temperature of the battery unit to the first upper limit value, and if the second mode is selected, the charging current is controlled based on a second correspondence relationship in which the first upper limit value corresponding to at least some temperatures is lower than the first correspondence relationship.

[0015] According to the above-mentioned electric work machine, in the first mode, priority is given to shortening the charging time, and in the second mode, priority is given to suppressing the rise in temperature of the battery unit, so that it is possible to achieve both shortening the charging time and suppressing the rise in battery temperature depending on the application.

[0016] 1 is an electrical block diagram of an electric working machine; FIG. 2 is a diagram showing the relationship between the temperature of a battery unit and the upper limit value (second upper limit value) of a discharge current; FIG. 3 is a diagram showing a series of discharge control flows; FIG. 4 is a diagram showing the corresponding relationship between the temperature of a battery unit and the upper limit value (first upper limit value) of a charge current; FIG. 5 is a diagram showing an example of a data structure of the upper limit value (first upper limit value) of a charge current; FIG. 6 is a diagram showing an example of a switching screen; FIG. 7 is a diagram showing a series of charge control flows; FIG. 8 is a diagram showing the relationship between a first weighting value and a minimum temperature; FIG. 9 is a diagram showing the relationship between a minimum temperature, a maximum temperature, and a first temperature; FIG. 10 is a diagram showing a series of display control flows; FIG. 11 is a diagram showing an example of a display screen; FIG. 12 is a diagram showing another example of a display screen; FIG. 13 is an overall side view of an electric working machine; FIG. 14 is a hydraulic circuit diagram provided in the electric working machine;

[0017] An embodiment of the present invention will be described below with reference to the drawings. The electric working machine 1 of the present invention includes a battery unit 30, an electric actuator 9 that operates using power supplied from the battery unit 30, and a working device 20 that operates when driven by the electric actuator 9. First, the overall configuration of the electric working machine 1 will be described.

[0018] 11 is an overall side view of the electric work machine 1. The electric work machine 1 is, for example, a backhoe. The electric work machine 1 includes a machine body (swivel base) 2, a traveling device 10, a dozer device 18, and a work device 20. On top of the machine body 2, there are provided a driver's seat 4 in which an operator sits, and a protection mechanism (cabin) 6 that protects the driver's seat 4 from the front, rear, left, right, and above.

[0019] An operating device 5 for operating the electric work machine 1 is provided around the driver's seat 4 inside the protection mechanism 6 (driver's cab 4R). The operator can operate the operating device 5 while seated in the driver's seat 4.

[0020] The protection mechanism 6 is not limited to the cabin shown in FIG. 11, but may be a cabin with a two-post structure or a three-post structure, or may be a canopy.

[0021] The traveling mechanism 12 is, for example, a crawler type traveling mechanism, and includes an idler 13, a drive wheel 14, a plurality of rollers 15, an endless crawler belt 16, and traveling motors ML and MR.

[0022] The machine body 2 is supported on a traveling frame 11 so as to be rotatable about a rotation axis X via a rotation bearing 3. A rotation motor MT is provided inside the machine body 2.

[0023] The working device 20 is supported on the front of the machine body 2. The working device 20 has a boom 21, an arm 22, a bucket (working tool) 23, and hydraulic cylinders C1 to C5. The base end of the boom 21 is pivotally mounted to a swing bracket 24 so as to be rotatable about a horizontal axis (an axis extending in the width direction of the machine body 2). This allows the boom 21 to swing up and down (vertically).

[0024] The electric work machine 1 performs work using the travel device 10, which has the travel motors ML, MR and hydraulic cylinders C1 to C5, the work device 20, and the swing motor MT described above. Hydraulic actuators such as the travel motors ML, MR, the swing motor MT, and the hydraulic cylinders C1 to C5 are included in hydraulic equipment. The travel device 10 is also a work device provided in the electric work machine 1.

[0025] Next, the hydraulic circuit provided in the electric working machine 1 will be described.

[0026] 12 is a diagram showing a hydraulic circuit K provided in the electric work machine 1. The hydraulic circuit K is provided with hydraulic devices such as hydraulic actuators C1 to C5, ML, MR, and MT, a control valve V, hydraulic pumps P1 and P2, a hydraulic oil tank T, an oil cooler 37, operation valves PV1 to PV6, an unload valve 58, and an oil passage 50.

[0027] Of the multiple hydraulic pumps P1, P2 provided, one is an actuation hydraulic pump P1 and the other is a control hydraulic pump P2. These hydraulic pumps P1, P2 are driven by the power of an electric actuator 9 (electric motor).

[0028] The hydraulic pump P1 draws hydraulic oil stored in a hydraulic oil tank T and then discharges the hydraulic oil toward the control valve V.

[0029] The control hydraulic pump P2 outputs hydraulic pressure for signals, controls, etc. by drawing in hydraulic oil stored in the hydraulic oil tank T and then discharging the hydraulic oil. In the example shown in Figure 12, for convenience, one actuation hydraulic pump P1 and one control hydraulic pump P2 are provided, but any appropriate number of pumps may be provided.

[0030] The control valve V has multiple control valves V1 to V8. Each of the control valves V1 to V8 controls (adjusts) the flow rate of hydraulic oil output from the hydraulic pumps P1 and P2 to each of the hydraulic actuators C1 to C5, ML, MR, and MT. As a result, the working device 20 is indirectly operated by the driving of the electric actuator 9 via the hydraulic oil discharged by the operating hydraulic pump P1.

[0031] The control valves PV1 to PV6 are operated in response to the operation of various control levers 5a (shown in FIG. 1) provided on the operating device 5. Pilot oil acts on each control valve V1 to V8 in proportion to the operation amount (operation amount) of each control valve PV1 to PV6, thereby moving the spool of each control valve V1 to V8. Then, an amount of hydraulic oil proportional to the amount by which the spool of each control valve V1 to V8 is moved is supplied to the hydraulic actuators C1 to C5, ML, MR, and MT to be controlled. Furthermore, each hydraulic actuator C1 to C5, ML, MR, and MT is driven in accordance with the amount of hydraulic oil supplied from each control valve V1 to V8.

[0032] The unloading valve 58 is a two-position switching valve that can be switched between a supply position and a suppression position. When in the supply position, the unloading valve 58 supplies hydraulic oil from the oil passage 50 to the operation valves PV1 to PV6. When in the suppression position, the unloading valve 58 stops the supply of hydraulic oil from the oil passage 50 to the operation valves PV1 to PV6, that is, prohibits or restricts the operation of the hydraulic actuators C1 to C5, ML, MR, and MT. As a result, when the unloading valve 58 is in the supply position, operation of the working device 20 is permitted, and when the unloading valve 58 is in the suppression position, operation of the working device 20 is prohibited or restricted.

[0033] Next, the electrical configuration of the electric operating machine 1 will be described.

[0034] Figure 1 is an electrical block diagram of an electric work machine 1. An operating device 5 of the electric work machine 1 has an operating lever 5a and an operating switch 5b. The operating lever 5a and the operating switch 5b can be operated by an operator seated in the driver's seat 4. For convenience, the operating lever 5a and the operating switch 5b are each shown as a single block in Figure 1, but in reality, multiple operating levers 5a and multiple operating switches 5b are provided.

[0035] The operation switch 5b includes a rotation speed operation device (accelerator dial) 5c for operating the rotation speed (motor rotation speed) of the electric motor 9, and a mode changeover switch 5d.

[0036] The mode selector switch 5d is a switch for inputting an instruction to switch the control device 7 between a discharge mode and a charge mode. The operation switch 5b and the mode selector switch 5d may be a rotary selector switch or a push button switch that can be operated by pressing. Furthermore, if the display device 60 described below is a touch panel that can be operated by touch, the operation switch 5b and the mode selector switch 5d may be an image (graphical interface) displayed on the display device 60.

[0037] The control device 7 is provided inside the machine body 2 or the protection mechanism 6, and has a CPU 7a and a storage unit 7b. The CPU 7a controls the operation of each unit provided in the electric work machine 1 as shown in Fig. 1. The storage unit 7b is composed of a memory and the like. Information, data, programs, etc. used by the CPU 7a to control the operation of each unit are stored in a readable and writable manner in the storage unit 7b.

[0038] As shown in Figure 1, the electric work machine 1 includes an electric actuator 9, an inverter 38, a junction box 39, a DC-DC converter 40, a charging port 41, a charger 45, a battery unit 30, and a low-voltage battery 33.

[0039] The electric actuator 9 operates on power supplied by the battery unit 30. In this embodiment, the electric actuator 9 is a drive source for the electric work machine 1, and is an electric motor configured, for example, as a permanent magnet embedded three-phase AC synchronous motor.

[0040] The inverter 38 is a motor drive device that supplies power from the battery unit 30 to the electric motor 9 to drive the electric motor 9. The inverter 38 is electrically connected to the electric motor 9 and the junction box 39. The inverter 38 converts DC power input from the battery unit 30 via the junction box 39 into three-phase AC power and supplies the three-phase AC power to the electric motor 9. This drives the electric motor 9. The inverter 38 can also arbitrarily adjust the current and voltage of the power supplied to the electric motor 9. The control device 7 controls the operation of the inverter 38 to drive or stop the electric motor 9.

[0041] In addition to the inverter 38, the junction box 39 is electrically connected to the battery unit 30, the DC-DC converter 40, and the charger 45. The junction box 39 outputs the power output from the battery unit 30 to the inverter 38 and the DC-DC converter 40. The junction box 39 also outputs the power input from the charger 45 to the battery unit 30.

[0042] The DC-DC converter 40 is a voltage conversion device that converts the voltage of the direct current input from the battery unit 30 via the junction box 39 into a different voltage. In this embodiment, the DC-DC converter 40 is a step-down converter that converts the high voltage of the battery unit 30 into a predetermined low voltage that is appropriate for the electrical equipment provided in the electric work machine 1. The DC-DC converter 40 supplies power to the low-voltage battery 33 after voltage conversion. The electrical equipment includes, for example, the control device 7, the display device 60, the oil cooler 37, and a radiator fan motor.

[0043] The charging port 41 has a connector into which a charging cable is fitted and a connection detection sensor 41 a. The charging port 41 is connected to an external power source (such as a commercial power source or a quick charger) via the charging cable.

[0044] The control device 7 switches to charging mode when the connection detection sensor 41a detects that a charging cable is connected to the charging port 41, and switches to discharging mode when the connection detection sensor 41a detects that a charging cable is not connected to the charging port 41.

[0045] Furthermore, the control device 7 does not switch between the discharge mode and the charge mode by using the mode changeover switch 5d and the connection detection sensor 41a. As another example, the control device 7 may switch to the discharge mode when the starter switch 8 is turned on (to start the electric work machine 1), or may switch to the charge mode when the starter switch 8 is not turned on. Alternatively, the control device 7 may switch to the discharge mode or the charge mode based on the operating state of the operating lever 5a or operating switch 5b that operate the traveling device 10 or the work device 20.

[0046] Charger 45 is electrically connected to charging port 41 and junction box 39, converts three-phase AC power input from an external power source via the charging cable and charging port 41 into DC power, and supplies the DC power to junction box 39. Charger 45 has a rectifier that converts the three-phase AC power into DC power, and an electronic circuit that adjusts the current and voltage of the DC power supplied to junction box 39.

[0047] The electronic circuit is composed of, for example, switching elements, diodes, resistors, electrolytic capacitors, etc. In this embodiment, the charger 45 uses the electronic circuit to adjust the current and voltage of the DC power supplied to the junction box 39, and charges the battery unit 30 by constant current charging or constant voltage charging. The current and voltage of the DC power when performing constant current charging or constant voltage charging are defined by a predetermined table stored in the memory unit 7b. The charger 45 adjusts the current and voltage according to a signal from the control device 7.

[0048] The battery unit 30 includes multiple battery packs 31, 32. Each battery pack 31, 32 is a secondary battery (storage battery) such as a lithium-ion battery, and is configured with at least one battery. When each battery pack 31, 32 is configured with multiple batteries, the multiple batteries are electrically connected in series and / or parallel. Furthermore, the batteries that make up each battery pack 31, 32 have multiple cells (battery cells) therein, and the multiple cells are electrically connected in series and / or parallel. Each battery pack 31, 32 has an electrical capacity sufficient to operate each part of the electric work machine 1 for a predetermined period of time. In this embodiment, the battery packs 31, 32 are connected in parallel.

[0049] In this embodiment, the battery unit 30 is provided with two battery packs 31 and 32, but the number of battery packs that the battery unit 30 has is not limited to two, and may be one, or three or more.

[0050] Further, battery management units (BMUs) 31a and 32a are provided in the battery packs 31 and 32, respectively. In FIG. 1, the BMUs 31a and 32a are provided in the corresponding battery packs 31 and 32, but the BMUs 31a and 32a may be built into the corresponding battery packs 31 and 32, or may be installed outside the battery packs 31 and 32.

[0051] The BMU 31a monitors and controls the corresponding battery pack 31. The BMU 32a monitors and controls the corresponding battery pack 32. Specifically, the BMUs 31a and 32a control the opening and closing of relays provided inside the battery packs 31 and 32 to control the start and stop of power supply from the battery packs 31 and 32. The BMUs 31a and 32a also detect the temperature, voltage, current, terminal voltage of the internal cells, etc. of the battery packs 31 and 32.

[0052] Specifically, for example, the BMUs 31a and 32a detect the temperatures of the battery packs 31 and 32 based on signals detected by temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d provided in the battery packs 31 and 32, respectively. In this embodiment, the electric work machine 1 is equipped with a plurality of temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d. The plurality of temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d are provided in different portions of the battery unit 30. Specifically, the temperature detection devices 31b, 31c, and 31d are arranged in different positions within the battery pack 31, and the temperature detection devices 32b, 32c, and 32d are arranged in different positions within the battery pack 32. Specifically, the battery unit 30 includes a plurality of battery cells, and the plurality of temperature detection devices 31 b, 31 c, 31 d, 32 b, 32 c, and 32 d are provided for different battery cells. In this embodiment, each of the battery packs 31 and 32 includes three temperature detection devices, but the number of temperature detection devices included in a battery pack is not limited to three.

[0053] Furthermore, the BMUs 31a and 32a detect the remaining capacity of the battery packs 31 and 32 by a voltage measurement method, for example, based on the terminal voltages of the cells inside the battery packs 31 and 32. Note that the method for detecting the remaining capacity of the battery packs 31 and 32 is not limited to the voltage measurement method, and other methods such as a coulomb counter method, a battery cell modeling method, an impedance track method, etc. Also, a capacity detection unit that detects the remaining capacity of the battery packs 31 and 32 may be provided separately from the BMUs 31a and 32a.

[0054] The low-voltage battery 33 is a storage battery with a lower voltage than the battery unit 30. The low-voltage battery 33 is charged with power supplied from the DC-DC converter 40. The low-voltage battery 33 supplies power to electrical components provided in the electric work machine 1. The capacity detection device 34 is made up of an electric circuit that detects the remaining capacity of the low-voltage battery 33.

[0055] 1, the electric work machine 1 is also equipped with a display device 60. The display device 60 is a fixed display device, a tablet-type terminal device capable of displaying images, or the like. The display device 60 is disposed around the operator's seat 4 within the protection mechanism 6 (for example, in front of the operator). The display device 60 displays an operation screen showing the motor rotation speed of the electric motor 9, the temperature of the cooling water for cooling the electrical components, the temperature of the hydraulic oil, etc.

[0056] Next, among the control methods for the electric work machine 1 in this embodiment, a description will be given of the discharge control for operating the work device 20. Note that, in this embodiment, a case will be described in which the battery packs 31 and 32 provided in the battery unit 30 are simultaneously discharged, but the BMUs 31a and 32a may control relays provided inside the battery packs 31 and 32 or a relay provided in the junction box 39 to discharge at least one battery pack provided in the battery unit 30. Similarly, with regard to the charge control described below, in this embodiment, a case will be described in which the battery packs 31 and 32 are simultaneously charged, but at least one battery pack may be charged.

[0057] When the current value of the discharge current (discharge current) of the battery unit 30 is large, the amount of heat generated increases, and there is a risk of deterioration of the battery unit 30 if the battery unit 30 becomes relatively hot. Therefore, the control device 7 limits the discharge current of the battery unit 30 and limits the output of the working device 20 as the temperature of the battery unit 30 increases.

[0058] As the temperature of the battery unit 30 increases, the control device 7 limits the output by lowering the upper limit of the discharge current supplied from the battery unit 30. Note that, for example, the control device 7 may limit the output of the working device 20 by controlling at least one of the rotation speed of the electric motor 9 and the unload valve 58 of the hydraulic circuit K in accordance with the temperature of the battery unit 30.

[0059] First, a case will be described in which the control device 7 controls the second upper limit value I_th2, which is the upper limit value of the discharge current, in accordance with the temperature of the battery unit 30 (second control temperature; hereinafter, sometimes referred to as the second temperature for controlling the battery unit 30). The second upper limit value I_th2 is defined corresponding to the temperature of the battery unit 30 (second control temperature). The control device 7 controls the second upper limit value I_th2 based on a discharge current value map that defines a correspondence relationship between the temperature of the battery unit 30 (second control temperature) and the second upper limit value I_th2. The discharge current value map is stored in advance in the storage unit 7b.

[0060] In the following description, the temperature of the battery unit 30 used by the control device 7 in the discharge control (second control temperature) is the maximum or minimum value of the plurality of temperature information detected by the temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d of the battery unit 30. Specifically, the control device 7 acquires, from the discharge current value map, the upper limit value of the discharge current corresponding to the highest temperature T_max and the upper limit value I_th1 of the discharge current corresponding to the lowest temperature T_min, and calculates the temperature corresponding to the lower upper limit value I_th1 of the discharge current corresponding to the highest temperature T_max or the upper limit value of the discharge current corresponding to the lowest temperature T_min as the second control temperature. Furthermore, the second control temperature is not limited to the maximum or minimum value of the plurality of temperature information, and may be a value calculated by another calculation method, such as the maximum value of the plurality of temperature information, and is not particularly limited.

[0061] The relationship between the temperature of the battery unit 30 (second control temperature) and the second upper limit value I_th2 (discharge current value map) will be described below.

[0062] 2 is a diagram showing the relationship between the second control temperature and the second upper limit value I_th2, in which the vertical axis represents the second upper limit value I_th2 and the horizontal axis represents the second control temperature.

[0063] When the second control temperature is sufficiently low (T<T_x), the second upper limit value I_th2 is defined as the maximum current value (I_max).

[0064] When the second control temperature rises and approaches the use limit temperature T_limit (T_x≦T<T_limit), the second upper limit value I_th2 is defined to decrease below I_max as the second control temperature increases. Here, the use limit temperature T_limit is a predetermined value determined by the characteristics of the battery unit 30, and may be, for example, 60 degrees or 70 degrees. When the temperature of the battery unit 30 becomes equal to or higher than the use limit temperature T_limit (T>T_limit), the second upper limit value I_th2 becomes zero.

[0065] The discharge current value map is stored in advance in the storage unit 7b, but the operator may be able to change the discharge current value map as desired by operating the operation device 5 or the display device 60. In the present embodiment, the discharge current value map is stored in advance in the storage unit 7b as a table-format data structure. Alternatively, as another example, a software program that expresses the relationship between the second control temperature and the second upper limit value I_th2 as a function may be stored in the storage unit 7b. In such a case, in the discharge mode, the CPU 7a of the control device 7 executes the software program to calculate the second upper limit value I_th2 according to the temperature (second control temperature) of the battery unit 30.

[0066] 2, the second upper limit value I_th2 is set to the maximum current value I_max until immediately before the temperature reaches the limit use temperature T_limit, thereby enabling the electric work machine 1 to continue work while maintaining the maximum power output from the battery unit 30, thereby maintaining work efficiency.

[0067] 2 is merely an example, and if priority is given to preventing the temperature of the battery unit 30 from increasing, the second upper limit value I_th2 may be set low from a stage where the second control temperature is low, thereby suppressing deterioration of the battery unit 30.

[0068] 3 is a diagram showing a series of steps in the discharge control. The series of steps shown in FIG. 3 are executed by the CPU 7a based on a software program stored in advance in the storage unit 7b of the control device 7.

[0069] The control device 7 determines whether the electric work machine 1 is currently in the discharge mode or the charge mode (S31). The control device 7 determines whether the electric work machine 1 is in the discharge mode or the charge mode based on the detection result of whether the connection detection sensor 41a detects whether the charging cable is connected to the charging port 41, or based on the switching state of the mode selector switch 5d, which is operated by the operator to switch between the discharge mode and the charge mode.

[0070] When the control device 7 determines that the current mode of the electric work machine 1 is the discharge mode (S31: NO), it acquires the temperature of the battery unit 30 detected by the BMU 31a and BMU 32a (second control temperature) (S32). The BMU 31a and BMU 32a calculate the second control temperature based on the temperature information detected by the plurality of temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d, and outputs the calculation result to the control device 7.

[0071] After step S32, the control device 7 acquires a second upper limit value I_th2 based on the detected second control temperature and the discharge current value map stored in the storage unit 7b (S33).

[0072] After step S33, the control device 7 outputs a command signal to the inverter 38 based on the operation of the operating device 5 (rotation speed operating device 5c) and the second upper limit value I_th2 (S34). At this time, the control device 7 controls the inverter 38 so that the current value of the power supplied to the electric motor 9 via the inverter 38 is equal to or less than the second upper limit value I_th2.

[0073] Note that the control device 7 only needs to be able to control the output of the working device 20 in accordance with the temperature (second control temperature) of the battery unit 30, and when the second control temperature reaches the usage limit temperature T_limit, the control device 7 may move the unload valve 58 from the supply position to the suppression position to restrict the operation of the working device 20. Furthermore, when the second control temperature reaches the usage limit temperature T_limit, the control device 7 may change the instruction signal output to the inverter 38 to reduce the target rotation speed of the electric motor 9 below the target rotation speed corresponding to the operation of the rotation speed operating device 5c, thereby controlling the operation of the working device 20.

[0074] After S34, the control device 7 determines whether to continue the operation of the working device 20 based on the operation state of the operating lever 5a and the operating switch 5b (S35). If the control device 7 determines that the operation should be continued (S35: YES), the process returns to step S32.

[0075] If the control device 7 determines not to continue the discharge process (S35: NO), it ends this process.

[0076] Next, the charge control in this embodiment will be described.

[0077] To charge the battery unit 30 in a short time, it is necessary to increase the current value of the current (charging current) supplied to the battery unit 30. However, as with discharging, the greater the current value of the current supplied to the battery unit 30, the greater the amount of heat generated by the battery unit 30. In such a case, the temperature of the battery unit 30 may rise, which may cause deterioration of the battery unit 30. Therefore, when the temperature of the battery unit 30 is relatively high, it is preferable to reduce the current value of the charging current to suppress the temperature rise of the battery unit 30.

[0078] Furthermore, if the control device 7 performs discharge control when the battery unit 30 is in a relatively high temperature state immediately after charging, the battery unit 30 will quickly reach the usage limit temperature T_limit, and the control device 7 will implement the output limitation described above to limit the operation of the working device 20 or stop the working device 20. Therefore, in order to perform the intended work without output limitation even immediately after charging, it is necessary to charge the battery unit 30 at a relatively low current value to suppress the temperature rise of the battery unit 30. In other words, the appropriate current value for charging the battery unit 30 differs depending on whether it is desired to complete charging in a short time or whether it is desired to operate the working device 20 without output limitation immediately after charging.

[0079] Therefore, the control device 7 in this embodiment controls a first upper limit value I_th1, which is an upper limit value of the charging current supplied to the battery unit 30, in accordance with the temperature of the battery unit 30. Furthermore, the control device 7 is switchable between a first mode in which the charging current is controlled based on a first correspondence relationship that associates the temperature of the battery unit 30 with the first upper limit value I_th1, and a second mode in which the charging current is controlled based on a second correspondence relationship in which the first upper limit value I_th1 corresponding to at least some temperatures is lower than that of the first correspondence relationship. In other words, the control method for the electric work machine 1 includes a first step of selecting either a predetermined first mode or a second mode, and a second step of controlling a first upper limit value I_th1, which is the upper limit value of the charging current supplied to the battery unit 30, depending on the mode selected in the first step and the temperature of the battery unit 30. In the second step, if the first mode is selected, the charging current is controlled based on a first correspondence relationship that associates the temperature of the battery unit 30 with the first upper limit value I_th1, and if the second mode is selected, the charging current is controlled based on a second correspondence relationship in which the first upper limit value I_th1 corresponding to at least some temperatures is lower than the first correspondence relationship.

[0080] The following describes a case in which the control device 7 controls the upper limit value (first upper limit value I_th1) of the charging current in accordance with the temperature of the battery unit 30 (first control temperature; hereinafter, similar to the second control temperature, this may be referred to as the second temperature for controlling the battery unit 30). The first upper limit value I_th1 is defined in accordance with the temperature (first control temperature) of the battery unit 30. The control device 7 controls the charging current based on a correspondence relationship (charging current value map) that associates the temperature (first control temperature) of the battery unit 30 with the upper limit value (first upper limit value I_th1) of the charging current. The charging current value map defines the relationship between the first control temperature and the first upper limit value I_th1, and is stored in advance in the storage unit 7b.

[0081] In the following description, the temperature of the battery unit 30 used by the control device 7 in charge control (first control temperature) is the maximum or minimum value of the multiple pieces of temperature information detected by the temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d of the battery unit 30. Specifically, the control device 7 obtains the upper limit value of the charging current corresponding to the highest temperature and the upper limit value of the charging current corresponding to the lowest temperature from the charging current value map, and calculates the temperature corresponding to the lower upper limit value of the charging current corresponding to the highest temperature or the lowest temperature as the first control temperature. The first control temperature is not limited to the maximum or minimum value of the multiple pieces of temperature information, and may be a value calculated by other calculation methods, such as the maximum value of the multiple pieces of temperature information, and is not particularly limited.

[0082] First, a charging current value map will be described, which is a correspondence relationship (first correspondence relationship, second correspondence relationship) that associates the temperature (first control temperature) of the battery unit 30 in the first mode and the second mode with the first upper limit value I_th1.

[0083] 4 is a diagram showing the correspondence relationship between the first control temperature and the first upper limit value I_th1. In Fig. 4, the vertical axis represents the first upper limit value I_th1, and the horizontal axis represents the first control temperature. In Fig. 4, the first correspondence relationship in the first mode is indicated by M1, and the second correspondence relationship in the second mode is indicated by M2.

[0084] The first mode (standard mode M1) prioritizes shortening the time until charging is completed. Hereinafter, the first mode will be referred to as standard mode M1. The second mode (heat generation suppression mode M2) prioritizes suppressing heat generation from the battery unit 30 during charging. Hereinafter, the second mode will be referred to as heat generation suppression mode M2. The heat generation suppression mode M2 ​​corresponds to a case where the user wishes to operate the working implement 20 without output limitations even immediately after charging, or a case where the electric working implement 1 is charged in an environment with a relatively high outside temperature, such as midsummer, when the temperature (first control temperature) of the battery unit 30 is already relatively high. Therefore, at least at some temperatures (e.g., the first temperature range R1 shown in FIG. 4 ), the first upper limit value I_th1 in the heat generation suppression mode M2 ​​is lower than the first upper limit value I_th1 in the standard mode M1.

[0085] In both standard mode M1 and heat generation suppression mode M2, the control device 7 decreases the first upper limit value I_th1 as the temperature of the battery unit 30 increases. Specifically, in standard mode M1, when the first control temperature is sufficiently low (T<T3), the first upper limit value I_th1 is at its maximum (I_max). As the first control temperature increases (rises), the control device 7 decreases (decreases). In other words, the first upper limit value I_th1 and the first control temperature have a monotonically decreasing relationship. The relationship between the first upper limit value I_th1 and the first control temperature in heat generation suppression mode M2 ​​also has a monotonically decreasing relationship.

[0086] 4, the first upper limit value I_th1 of the heat generation suppression mode M2 ​​in a predetermined first temperature range R1 of the temperature of the battery unit 30 is lower than the first upper limit value I_th1 of the standard mode M1 in the first temperature range R1. Also, the first upper limit value I_th1 of the heat generation suppression mode M2 ​​in a second temperature range R2 in which the temperature of the battery unit 30 is higher than that in the first temperature range R1 is approximately equal to the first upper limit value I_th1 of the standard mode M1 in the second temperature range R2.

[0087] Furthermore, in at least one of the standard mode M1 and the heat generation suppression mode M2, the first upper limit value I_th1 in a predetermined first temperature zone R1 is constant with respect to the first control temperature, which is the temperature of the battery unit 30. That is, the first upper limit value I_th1 is constant with respect to the first control temperature and does not necessarily decrease (decrease) as the first control temperature increases. The first upper limit value I_th1 may be constant in some temperature zones of the first control temperature. For example, in the present embodiment, in the first temperature zone R1 where the first control temperature is low, the first upper limit value I_th1 in the standard mode M1 is a constant value. Similarly, the first upper limit value I_th1 in the heat generation suppression mode M2 ​​is also a constant value.

[0088] 5 shows an example of the data structure of the charging current value map stored in the storage unit 7b. The storage unit 7b stores first control temperatures and first upper limit values ​​I_th1 corresponding to the first control temperatures in table format. The charging current value map for the standard mode M1 is table D1. The charging current value map for the heat generation suppression mode M2 ​​is table D2.

[0089] The charging current value map is stored in advance in the storage unit 7b, but the operator may be able to change the charging current value map as desired by operating the operation device 5 or the display device 60. As another example, a software program that expresses the relationship between the first control temperature and the first upper limit value I_th1 as a function may be stored in the storage unit 7b. In such a case, in the charge mode, the CPU 7a of the control device 7 executes the software program to calculate the first upper limit value I_th1 according to the temperature (first control temperature) of the battery unit 30.

[0090] Next, a process in which the control device 7 switches (selects) between the standard mode M1 and the heat generation suppression mode M2 ​​will be described.

[0091] The electric operating machine 1 is equipped with switches B1, B2, and B3 for switching (selecting) between a standard mode M1 and a heat-reducing mode M2. The switches B1, B2, and B3 are, for example, images (graphical interfaces) displayed on the display device 60. The control device 7 switches between the standard mode M1 and the heat-reducing mode M2 ​​when a predetermined operation is performed on the operating device 5 and the switches B1, B2, and B3 are operated. If the display device 60 is a touch panel that can be touched, the control device 7 may switch between the standard mode M1 and the heat-reducing mode M2 ​​when the switches B1, B2, and B3 displayed on the display device 60 are touched.

[0092] FIG. 6 is a diagram showing an example of a switching screen displayed on the display device 60. As shown in FIG.

[0093] When a predetermined operation is performed on the operating device 5, the control device 7 causes the display device 60 to display a switching screen G1. In this embodiment, the switching screen G1 includes a message Mg1 (e.g., "Charge Mode Setting") indicating that this is a screen for performing a switching operation, a message Mg2 (e.g., "Standard") and a message Mg3 (e.g., "Heat Reduction") indicating modes that can be set on the switching screen G1, and a switch (radio button B1, radio button B2, and decision button B3). In this embodiment, the switch includes the radio button B1, radio button B2, and decision button B3. The operator selects a desired mode using the radio button B1 and radio button B2 of the switch and confirms the selected mode using the decision button B3.

[0094] The control device 7 references the memory unit 7b and displays the acquired current mode information on the display device 60. For example, in the switching screen G1 of Fig. 6, the radio button B2 is black, i.e., ON. This indicates that the current setting of the electric operating machine 1 is the heat suppression mode M2.

[0095] When a predetermined operation is performed on the operating device 5, the control device 7 causes the display device 60 to display a mode switching indication. For example, the control device 7 causes the display device 60 to display a mode switching indication for the radio button B1 and the radio button B2, switching between on (black) and off (white).

[0096] When the confirm button B3 is pressed by a predetermined operation of the operating device 5, the control device 7 stores the selected mode in the storage unit 7b. For example, in Fig. 6, the switching screen G1 shows that the message Mg3 ("Heat suppression") is selected. When the confirm button B3 is pressed in this state, the control device 7 stores in the storage unit 7b that the selected mode is heat suppression mode M2.

[0097] The configuration of the switching screen G1 is merely an example. For example, the user interface may be in a pull-down format. Also, the selected mode may be indicated by changing the background color of the message Mg2 and the message Mg3.

[0098] Furthermore, the control device 7 may switch between the standard mode M1 and the heat-reducing mode M2 ​​by voice recognition or image recognition, rather than by a predetermined operation on the operating device 5. For example, the control device 7 recognizes the voice of the worker acquired through a voice input device and switches between the standard mode M1 and the heat-reducing mode M2. The control device 7 also recognizes barcodes or characters captured by a camera device, determines which mode to set, and switches between the standard mode M1 and the heat-reducing mode M2.

[0099] Next, a series of steps for charge control will be described in the control method for the electric operating machine 1 according to this embodiment. Fig. 7 is a diagram showing a series of steps for charge control by the control device 7. The series of processes shown in Fig. 7 are executed by the CPU 7a based on a software program stored in advance in the storage unit 7b of the control device 7.

[0100] When the control device 7 determines that the current mode of the electric operating machine 1 is the charge mode (FIG. 3, S31: YES), it refers to the storage unit 7b and switches the mode for determining the first upper limit value I_th1 (S71). Specifically, the control device 7 refers to the storage unit 7b, reads whether the current mode is the standard mode M1 or the heat generation suppression mode M2, and acquires the reference destination of the charging current value map to be referenced when determining the first upper limit value I_th1.

[0101] After step S71, the control device 7 acquires the first control temperatures detected by the BMUs 31a and 32a (S72). The BMUs 31a and 32a calculate the first control temperatures based on the temperature information detected by the temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d, and output the calculation results to the control device 7.

[0102] After step S72, the control device 7 controls the first upper limit value I_th1, which is the upper limit value of the charging current supplied to the battery unit 30, in accordance with the temperature (first control temperature) of the battery unit 30 (S73). In other words, the control device 7 obtains the first upper limit value I_th1, which is the upper limit value of the charging current, based on the first control temperature, information on the current mode, and the charging current value map corresponding to the mode.

[0103] For example, when the current mode is heat generation suppression mode M2 ​​and the detected first control temperature is T1a (T1<T1a<T2), the control device 7 references table D2, which is a discharge current value map corresponding to heat generation suppression mode M2, and determines the corresponding first upper limit value I_th1 to be I4. On the other hand, when the current mode is standard mode M1 and the detected first control temperature is T1a (T1<T1a<T2), the control device 7 references table D1, which is a discharge current value map corresponding to standard mode M1, and determines the first upper limit value I_th1 to be I_max. In other words, even if the temperature (first control temperature) of the battery unit 30 is the same, the first upper limit value I_th1 in heat generation suppression mode M2 ​​(second mode) is lower than the first upper limit value I_th1 in standard mode M1 (first mode).

[0104] After step S73, the control device 7 outputs an instruction signal of the first upper limit value I_th1 to the charger 45. The charger 45 charges the battery unit 30 by adjusting the current of the DC power output to the battery unit 30 so that it is equal to or less than the first upper limit value I_th1 (S74).

[0105] After step S74, the control device 7 determines whether to continue charging the battery unit 30 based on the state (remaining capacity) of the battery unit 30 detected by the BMU 31a and the BMU 32a (S75).

[0106] For example, the control device 7 determines not to continue charging if the remaining capacity of the battery unit 30 is 100%. Furthermore, the criterion for determining whether to continue charging may be switched depending on the current mode. For example, in standard mode M1, the control device 7 determines not to continue charging if the remaining capacity of the battery unit 30 is 100%. On the other hand, in heat generation suppression mode M2, the control device 7 determines not to continue charging if the remaining capacity of the battery unit 30 is 80%. In this embodiment, the remaining capacity value of the battery unit 30, which serves as the criterion, is linked to tables D1 and D2 and stored in advance in the memory unit 7b.

[0107] If the control device 7 determines to continue charging the battery unit 30 (S75: YES), the process returns to step S72.

[0108] When the control device 7 determines that the battery unit 30 will not continue charging (S75: NO), it ends this process.

[0109] Next, the display control of the temperature of the battery unit 30, which is one of the control methods for the electric operating machine 1, will be described.

[0110] As described above, if the battery unit 30 is at a relatively high temperature, the control device 7 controls the current supplied to the battery unit 30 to be reduced, which increases the time required to complete charging. Also, at low temperatures, the battery's ability to accept charge decreases due to its characteristics, which increases the time required to complete charging. In other words, the time required to charge the battery unit 30 tends to be shorter at medium temperatures and longer at high or low temperatures.

[0111] Therefore, when the electric work machine 1 is equipped with multiple temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d, in order for the operator to know an estimate of the charging time of the battery unit 30 from the temperature of the battery unit 30, if the battery unit 30 is relatively high, it is preferable that the display device 60 display the highest temperature (maximum value) of the multiple temperatures detected by the temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d. Similarly, if the battery unit 30 is relatively low, it is preferable that the display device 60 display the lowest temperature (minimum value) of the multiple temperatures detected by the temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d.

[0112] However, when the displayed temperature changes from the maximum temperature to the minimum temperature or from the minimum temperature to the maximum temperature, the change in the value displayed on the display device 60 becomes large, which may confuse the operator. Therefore, when the battery unit 30 is at a medium temperature, the display device 60 displays a temperature for display that is weighted by the maximum temperature and the minimum temperature.

[0113] More specifically, the control device 7 calculates a first temperature T_show, which is a temperature to be displayed, based on a minimum temperature T_min and a maximum temperature T_max of the temperatures detected by the plurality of temperature detecting devices 31b, 31c, 31d, 32b, 32c, and 32d that detect the temperature of the battery unit 30, and a weighting value that weights the minimum temperature T_min more heavily as the minimum temperature T_min is lower. The display device 60 displays the first temperature T_show calculated by the control device 7. The control method for the electric operating machine 1 includes the steps of: identifying the minimum temperature T_min and the maximum temperature T_max of the temperatures detected by the plurality of temperature detecting devices 31b, 31c, 31d, 32b, 32c, and 32d; and calculating the first temperature T_show based on the minimum temperature T_min, the maximum temperature T_max, and a weighting value that weights the minimum temperature T_min more heavily as the minimum temperature T_min is lower.

[0114] The weighting values ​​used to calculate the first temperature T_show vary depending on the minimum temperature T_min. The first weighting value α, which is the weighting value by which the minimum temperature T_min is multiplied, increases as the minimum temperature decreases, and the second weighting value (1-α), which is the weighting value by which the maximum temperature T_max is multiplied, increases as the minimum temperature increases.

[0115] If the minimum temperature T_min is less than a first predetermined value th1 (T_min<th1), the control device 7 sets the minimum temperature T_min as the first temperature T_show. The first predetermined value th1 may be, for example, 0 degrees or minus 5 degrees, and is not particularly limited. If the minimum temperature T_min is equal to or greater than a second predetermined value (th2<=T_min), the control device 7 sets the maximum temperature T_max as the first temperature T_show. The second predetermined value th2 may be, for example, 20 degrees or 30 degrees, and is not particularly limited. If the minimum temperature T_min is equal to or greater than the first predetermined value th1 but less than the second predetermined value th2 (th1<=T_min<th2), the control device 7 calculates the first temperature T_show, which is a temperature for display, using the minimum temperature T_min, the maximum temperature T_max, and a weighting value.

[0116] In other words, the control device 7 calculates the first temperature T_show based on the following formula.

[0117] T_show = T_min x α + T_max x (1-α) (Equation 1) The first weighting value, which is the weighting value by which the minimum temperature is multiplied, is α. The second weighting value, which is the weighting value by which the maximum temperature is multiplied, is 1-α. The first weighting value α and the second weighting value 1-α are the ratios of the minimum temperature T_min and the maximum temperature T_max to the first temperature T_show, which is the temperature to be displayed. The first weighting value α and the second weighting value 1-α add up to 1. In other words, once the first weighting value α is determined, the second weighting value 1-α is also uniquely determined.

[0118] Here, the relationship between the first weighting value α and the minimum temperature T_min will be explained using a diagram. Fig. 8A is a diagram showing the relationship between the first weighting value α and the minimum temperature T_min. In Fig. 8A, the vertical axis represents the first weighting value α, and the horizontal axis represents the minimum temperature T_min. The first weighting value α increases as the minimum temperature T_min decreases. In other words, the first weighting value α and the minimum temperature T_min have a monotonically decreasing relationship.

[0119] The first weighting value α ranges from 0 to 1 (0≦α≦1). If the minimum temperature T_min is less than the first predetermined value th1 (T_min<th1), the first weighting value α is set to 1. That is, the following equation is obtained.

[0120] T_show=T_min (Equation 2) If the minimum temperature T_min is equal to or greater than the second predetermined value th2 (th2<=T_min), the first weighting value α is set to zero.

[0121] T_show = T_max (Equation 3) The first weighting value α decreases at a constant rate in the temperature range from the first predetermined value th1 to the second predetermined value th2. That is, it decreases linearly and monotonically (FIG. 8A: 81). The amount of change in the first weighting value α does not have to be constant, and may vary nonlinearly. For example, the first weighting value α may vary as shown in FIG. 8A at 82 or as shown in FIG. 8A at 83.

[0122] FIG. 8B shows the relationship between the minimum temperature, the maximum temperature, and the display temperature. When the minimum temperature T_min (FIG. 8B: 84) is less than the first predetermined value th_1 (T_min<th1), the first temperature T_show (FIG. 8B: 86) is equal to the minimum temperature T_min. When the minimum temperature T_min is equal to or greater than the first predetermined value th1 and less than the second predetermined value th2 (th1<=T_min<th2), the difference between the first temperature T_show and the minimum temperature T_min increases as the minimum temperature T_min increases, and the first temperature T_show approaches the maximum temperature T_max. When the minimum temperature T_min is equal to or greater than the second predetermined value th_2 (th2<=T_min), the first temperature T_show is equal to the maximum temperature T_max (FIG. 8B: 85).

[0123] In this embodiment, the first weighting value α corresponding to the minimum temperature T_min is stored in advance in the storage unit 7b as a table-type data structure. In another example, a software program that expresses the relationship between the minimum temperature T_min and the first weighting value α as a function may be stored in the storage unit 7b. In such a case, the CPU 7a of the control device 7 executes the software program to calculate the first weighting value α corresponding to the minimum temperature T_min.

[0124] Furthermore, in this embodiment, in the temperature display control performed by the control device 7, after the first weighting value α stored in the storage unit 7b is identified, the result of dividing the first weighting value α by 1 is set as the second weighting value 1-α. On the other hand, like the first weighting value α, the second weighting value 1-α may be stored in advance in the storage unit 7b as a table-type data structure. Furthermore, in another example, a software program that expresses the relationship between the minimum temperature T_min and the second weighting value 1-α as a function may be stored in the storage unit 7b. In such a case, the CPU 7a of the control device 7 executes the software program to calculate the second weighting value 1-α corresponding to the minimum temperature T_min.

[0125] As described above, the control device 7 calculates a second temperature for controlling the battery unit 30 separately from the first temperature T_show. The second temperature is, for example, the first control temperature in the charge control and / or the second control temperature in the discharge control. The control device 7 controls at least one of the charge current during charging and the discharge current during discharging of the battery unit 30 based on the second temperature.

[0126] Next, a series of steps in the temperature display control of the battery unit 30 by the control device 7 will be described with reference to Fig. 9. The series of steps shown in Fig. 9 are executed by the CPU 7a based on a software program stored in advance in the storage unit 7b of the control device 7.

[0127] The control device 7 acquires the temperatures detected by the BMUs 31a and 32a (S91). The BMUs 31a and 32a output temperature information detected by the temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d to the control device 7. After S91, the control device 7 detects the minimum temperature T_min and the maximum temperature T_max from the plurality of pieces of temperature information (S92).

[0128] After S92, the control device 7 determines a weighting value (S93). Specifically, the control device 7 references the storage unit 7b and acquires the first weighting value α corresponding to the detected minimum temperature T_min. The control device 7 performs an operation of dividing the first weighting value α by 1 to determine the second weighting value 1-α.

[0129] After S93, the control device 7 calculates the first temperature T_show (S94). The first temperature T_show is calculated using the minimum temperature T_min, the maximum temperature T_max, and a weighting value.

[0130] After S94, the control device 7 causes the display device 60 of the electric operating machine 1 to display the calculated first temperature T_show. The control device 7 causes the display device 60 to display, for example, the display screen G2 (S95).

[0131] 10A is a diagram showing an example of a display screen G2. The display screen G2 is made up of a battery temperature display section 61 that displays the temperature of the battery unit 30, a remaining battery capacity display section 62 that displays the remaining capacity of the battery unit 30, and the like.

[0132] The battery temperature display unit 61 displays the first temperature T_show calculated in S94. The battery remaining capacity display unit 62 displays the remaining capacity of the battery unit 30 (e.g., battery packs 31, 32) detected by the BMU 31a. For example, the battery remaining capacity display unit 62 displays the remaining capacity of either the battery pack 31 or 32 having the smallest remaining capacity. In this example, since the remaining capacity of the battery pack 31 is small, the remaining capacity of the battery pack 31 is displayed. Note that the battery remaining capacity display unit 62 may switch the remaining capacity of the battery packs 31 and 32 in accordance with a selection operation of the operation device 5. Alternatively, the battery remaining capacity display unit 62 may display the total remaining capacity of the battery packs 31 and 32.

[0133] The control device 7 may calculate the first temperature T_show based on the minimum temperature T_min and the maximum temperature T_max of the temperatures detected by the temperature detecting devices 31b, 31c, 31d, 32b, 32c, and 32d, and a weighting value in which the weight of the minimum temperature increases as the minimum temperature decreases, and the calculation method is not limited to the above-described method. For example, when a predetermined temperature is set as the median temperature (reference temperature) and the minimum temperature is the reference temperature, the control device 7 may use the average temperature of the temperatures detected by the temperature detecting devices 31b, 31c, 31d, 32b, 32c, and 32d as the first temperature T_show. In such a case, if the minimum temperature is less than the reference temperature, the control device 7 calculates the first temperature T_show using the average temperature, the minimum temperature T_min, and the weighting value, and if the minimum temperature is equal to or greater than the reference temperature, the control device 7 calculates the first temperature T_show using the average temperature, the maximum temperature T_max, and the weighting value.

[0134] Furthermore, although an example in which the temperature of the battery unit 30 is displayed has been described, the first temperatures T_show of the battery packs 31 and 32 may be calculated individually.

[0135] The control device 7 acquires from the BMU 31a the minimum and maximum temperatures detected by the temperature detection devices 31b, 31c, and 31d included in the battery pack 31, and calculates a first temperature T_show for the battery pack 31. As shown in Fig. 10B , the control device 7 causes the display device 60 to display the first temperature T_show for the battery pack 31 on the battery temperature display unit 61a.

[0136] Similarly, the control device 7 acquires from the BMU 32a the minimum and maximum temperatures detected by the temperature detection devices 32b, 32c, and 32d included in the battery pack 32, and calculates a first temperature T_show for the battery pack 32. As shown in Fig. 10B , the control device 7 causes the display device 60 to display the first temperature T_show for the battery pack 32 on the battery temperature display unit 61b.

[0137] Furthermore, although the battery temperature display units 61, 61a, 61b are displayed as gauges, the calculated first temperature T_show may be displayed as a numerical value on the display screen.

[0138] In the above-described embodiment, the second temperature (first control temperature, second control temperature) of the battery unit 30 in the charge control and the discharge control is the temperature corresponding to the lower upper limit value among the maximum temperature and the minimum temperature among the plurality of temperature information detected by the plurality of temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d. However, the second temperature may be calculated based on the first predetermined value th1 and the second predetermined value th2. Specifically, for example, when the minimum temperature T_min is less than the first predetermined value th1, the control device 7 controls at least one of the charge current during charging and the discharge current during discharging of the battery unit 30 based on the minimum temperature T_min. Furthermore, when the minimum temperature T_min is equal to or greater than the second predetermined value th2, the control device 7 controls at least one of the charge current and the discharge current based on the maximum temperature T_max.

[0139] In this embodiment, when the minimum temperature T_min detected by the temperature detectors 31b, 31c, 31d, 32b, 32c, and 32d is less than the first predetermined value th1, the control device 7 controls the charging current based on the minimum temperature T_min as the second temperature (second control temperature). When the maximum temperature T_max detected by the temperature detectors 31b, 31c, 31d, 32b, 32c, and 32d is equal to or greater than the second predetermined value th2, the control device 7 controls the discharging current based on the maximum temperature T_max as the second temperature (second control temperature).

[0140] On the other hand, when the minimum temperature T_min of the temperatures detected by the temperature detecting devices 31b, 31c, 31d, 32b, 32c, and 32d is less than the first predetermined value th1, the control device 7 controls the discharge current using the minimum temperature T_min as the second temperature (first control temperature).When the maximum temperature T_max of the temperatures detected by the temperature detecting devices 31b, 31c, 31d, 32b, 32c, and 32d is equal to or greater than the second predetermined value th2, the control device 7 controls the discharge current using the maximum temperature T_max as the second temperature (first control temperature).

[0141] In such a case, if the minimum temperature T_min of the temperatures detected by the temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d is equal to or greater than the first predetermined value th1, and the maximum temperature T_max of the temperatures detected by the temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d is less than the second predetermined value th2, the control device 7 may use the minimum temperature T_min, the maximum temperature T_max, or the average temperature of the minimum temperature T_min and the maximum temperature T_max as the second temperature.

[0142] In the above-described embodiment, the standard mode M1 and the heat suppression mode M2 ​​are switched when a predetermined operation is performed on the operating device 5, i.e., when an operator issues an instruction to do so, but the control device 7 may also automatically determine the mode based on predetermined conditions and switch the mode.

[0143] For example, the control device 7 may determine whether to use the standard mode M1 or the heat generation suppression mode M2 ​​according to current time information. Specifically, for example, if the current time is daytime, it is assumed that the user will want to operate the electric work machine 1 immediately after charging (i.e., want to discharge the battery unit 30), so the control device 7 stores in the memory unit 7b that the mode is the heat generation suppression mode M2. On the other hand, if the current time is nighttime, the control device 7 stores in the memory unit 7b that the mode is the standard mode M1.

[0144] Furthermore, for example, the control device 7 may determine whether to select standard mode M1 or heat generation suppression mode M2 ​​depending on the detection result of the outside air temperature detected by the outside air temperature detection device. Specifically, if the current outside air temperature is higher than a predetermined temperature, it is assumed that the temperature of the battery unit 30 is already high, and therefore the control device 7 stores in the memory unit 7b that the mode is heat generation suppression mode M2. The predetermined temperature may be, for example, 30 degrees or 35 degrees. On the other hand, if the current outside air temperature is lower than the predetermined temperature, the control device 7 stores in the memory unit 7b that the mode is standard mode M1.

[0145] Furthermore, the control device 7 may determine whether to use the standard mode M1 or the heat generation suppression mode M2 ​​depending on the current season. Specifically, the control device 7 determines the current season from date information. If the current season is summer, the outside temperature is high and the temperature of the battery unit 30 is assumed to be already high, so the control device 7 stores in the memory unit 7b that the mode is the heat generation suppression mode M2. On the other hand, if the current season is other than summer, the control device 7 stores in the memory unit 7b that the mode is the standard mode M1.

[0146] Furthermore, the control device 7 may determine whether to use standard mode M1 or heat suppression mode M2 ​​depending on the region in which the electric work machine 1 is working. Specifically, the control device 7 determines whether the region is one where the outside temperature is relatively high based on region information acquired from a positioning device included in the electric work machine 1 or manually set by the operator. If the region in which the electric work machine 1 is working is one where the outside temperature is relatively high, it is expected that the temperature of the battery unit 30 will easily become high. Therefore, the control device 7 stores in the memory unit 7b that the mode is heat suppression mode M2. On the other hand, if the region is not one where the outside temperature is high, the control device 7 stores in the memory unit 7b that the mode is standard mode M1.

[0147] Furthermore, the control device 7 may determine whether to use the standard mode M1 or the heat generation suppression mode M2 ​​based on the cumulative operating time for which the battery unit 30 has flowed current up to now. Specifically, a battery unit 30 with a cumulative operating time longer than a predetermined time is likely to be degraded. The control device 7 stores in the memory unit 7b that the mode is the heat generation suppression mode M2 ​​to prevent further degradation of the battery unit 30. On the other hand, if the cumulative battery operating time of the battery unit 30 is shorter than the predetermined time, the control device 7 stores in the memory unit 7b that the mode is the standard mode M1.

[0148] Furthermore, the control device 7 may determine whether to operate in standard mode M1 or heat generation suppression mode M2 ​​based on the most recent power consumption (discharged power) of the electric work machine 1. Specifically, if the operation performed on the electric work machine 1 immediately before charge control required a large power output, there is a high possibility that the next operation will also require a large power output. For this reason, the control device 7 stores in the memory unit 7b that the mode is heat generation suppression mode M2 ​​so that there is no restriction on the output from the battery unit 30, even immediately after charging. On the other hand, if the most recent power consumption is low, the control device 7 assumes that the next operation will not require a large power output, and stores in the memory unit 7b that the mode is standard mode M1.

[0149] The control device 7 may also determine whether to operate in standard mode M1 or heat suppression mode M2 ​​depending on the implement attached to the electric work machine 1. Specifically, if the attached implement (hydraulic attachment) requires a large amount of power to operate, it is likely that a large amount of power output will be required when operating the implement immediately after charging. For this reason, the control device 7 stores in the memory unit 7b that the mode is heat suppression mode M2 ​​so that there is no restriction on the output from the battery unit 30, even immediately after charging. On the other hand, if the attached implement does not require a large amount of power to operate, the control device 7 stores in the memory unit 7b that the mode is standard mode M1.

[0150] Furthermore, the control device 7 may determine whether to use the standard mode M1 or the heat generation suppression mode M2 ​​depending on the remaining capacity of the battery unit 30 at the start of charging. Due to battery characteristics, when charging is performed using constant current charging, it is necessary to set a lower charging current value output to the battery packs 31, 32 as the battery approaches full charge. Therefore, if the remaining capacity of the battery unit 30 is greater than a predetermined value (e.g., 80% or more) when charging starts, the control device 7 stores in the memory unit 7b that the mode is the heat generation suppression mode M2. On the other hand, if the remaining capacity of the battery unit 30 is less than the predetermined value (e.g., less than 80%), the control device 7 stores in the memory unit 7b that the mode is the standard mode M1. As described above, the control device 7 automatically sets the mode for controlling the first upper limit value I_th1, which is the upper limit value of the charging current, thereby enabling both improved work efficiency and suppression of deterioration of the battery unit 30.

[0151] Furthermore, in the above-described embodiment, two modes, the standard mode M1 and the heat generation suppression mode M2, were used as examples. However, the control device 7 is only required to be able to switch between a first mode in which the charging current is controlled based on a predetermined first correspondence relationship, and a second mode in which the charging current is controlled based on a second correspondence relationship in which the first upper limit value I_th1 corresponding to at least some temperatures is lower than the first correspondence relationship. The number of modes is not limited to two, and a configuration may be adopted in which the predetermined first correspondence relationship is corrected to continuously change the first upper limit value I_th1.

[0152] The electric working machine 1 and the control method for the electric working machine 1 according to the first embodiment described above have the following advantages.

[0153] (Item A1) An electric work machine 1 comprising a battery unit 30, an electric actuator (electric motor) 9 operated by power supplied by the battery unit 30, a work device 20 operated by driving the electric actuator 9, temperature detection devices 31b, 31c, 31d, 32b, 32c, 32d that detect the temperature of the battery unit 30, and a control device 7 that controls a first upper limit value I_th1, which is the upper limit value of the charging current supplied to the battery unit 30, in accordance with the temperature (first control temperature) of the battery unit 30, wherein the control device 7 is switchable between a first mode (standard mode M1) that controls the charging current based on a first correspondence relationship that associates the temperature (first control temperature) of the battery unit 30 with the first upper limit value I_th1, and a second mode (heat generation suppression mode M2) that controls the charging current based on a second correspondence relationship in which the first upper limit value I_th1 corresponding to at least some temperatures is lower than the first correspondence relationship.

[0154] According to the invention related to item A1, it is possible to shorten the charging time and suppress the increase in battery temperature at the same time depending on the application. That is, by switching to the setting of the first upper limit value I_th1, which is the upper limit value of the charging current, appropriate for charging in a short time and charging while suppressing the increase in the temperature of the battery unit 30, respectively, the operation can be performed efficiently.

[0155] (Item A2) The electric operating machine 1 according to Item A1, wherein the control device 7 lowers the first upper limit value I_th1 as the temperature (first control temperature) of the battery unit 30 increases in each of the first mode and the second mode.

[0156] According to the invention relating to item A2, the battery unit 30 can be charged while suppressing deterioration of the battery unit 30.

[0157] (Item A3) The first upper limit value I_th1 of the second mode in a predetermined first temperature range R1 of the temperature (first control temperature) of the battery unit 30 is lower than the first upper limit value I_th1 of the first mode in the first temperature range R1, and the first upper limit value I_th1 of the second mode in a second temperature range R2 in which the temperature (first control temperature) of the battery unit 30 is higher than that in the first temperature range R1 is approximately the same as the first upper limit value I_th1 of the first mode in the second temperature range R2.

[0158] According to the invention relating to item A3, in the second temperature section R2, the first upper limit value I_th1 of the first mode and the second mode are approximately the same, while the first upper limit value I_th1 of the first mode and the first upper limit value I_th1 of the second mode in the first temperature section R1 can be made to differ more significantly.

[0159] (Item A4) An electric work machine 1 described in Item A3, wherein in at least one of the first mode and the second mode, the first upper limit value I_th1 of the first temperature section R1 is constant relative to the temperature of the battery unit 30 (first control temperature).

[0160] According to the invention related to item A4, the charging speed of the battery unit 30 can be kept constant within a certain temperature range. Furthermore, by reducing the number of times the current value is switched, the charging control process can be easily implemented.

[0161] (Item A5) The electric work machine 1 according to any one of items A1 to A4, wherein the control device 7 controls the output of the work device 20 in accordance with the temperature of the battery unit 30 (second control temperature).

[0162] According to the invention related to item A5, discharge suited to the temperature characteristics of the battery unit 30 becomes possible.

[0163] (Item A6) An electric work machine 1 described in any of items A1 to A5, in which the control device 7 controls a second upper limit value I_th2, which is the upper limit value of the discharge current supplied from the battery unit 30 to the electric actuator 9, in accordance with the temperature (second control temperature) of the battery unit 30.

[0164] According to the invention related to item A6, the battery unit 30 can be discharged, i.e., the working device 20 can be operated, while suppressing deterioration of the battery unit 30.

[0165] (Item A7) The electric operating machine 1 according to Item A6, wherein the control device 7 decreases the second upper limit value I_th2 as the temperature (second control temperature) of the battery unit 30 increases.

[0166] According to the invention related to item A7, the battery unit 30 can be discharged, that is, the working device 20 can be operated while suppressing deterioration of the battery unit 30.

[0167] (Item A8) The electric operating machine 1 according to any one of items A1 to A7, which is provided with a switching device B1, B2, B3 for switching between the first mode and the second mode.

[0168] According to the invention related to item A8, the operator can arbitrarily switch between the first mode and the second mode, and can perform charging as intended.

[0169] (Item A9) A control method for an electric work machine 1 including a battery unit 30, an electric actuator 9 operated by power supplied by the battery unit 30, a work device 20 operated by driving the electric actuator 9, temperature detection devices 31b, 31c, 31d, 32b, 32c, 32d that detect the temperature of the battery unit 30, and a control device 7 that controls charging of the battery unit 30, the method comprising: a first step of selecting either a first mode or a second mode; and a second step of controlling a first upper limit value I_th1, which is an upper limit value of the charging current supplied to the battery unit 30, in accordance with the temperature (first control temperature) of the battery unit 30, wherein in the second step, if the first mode is selected, the charging current is controlled based on a first correspondence relationship that associates the temperature (first control temperature) of the battery unit 30 with the first upper limit value I_th1, and if the second mode is selected, the charging current is controlled based on a second relationship in which the first upper limit value I_th1 corresponding to at least some of the temperatures is lower than the first correspondence relationship.

[0170] According to the invention related to item A9, it is possible to shorten the charging time and suppress the increase in battery temperature at the same time depending on the application. That is, by switching to the setting of the first upper limit value I_th1, which is the upper limit value of the charging current, appropriate for charging in a short time and charging while suppressing the increase in the temperature of the battery unit 30, respectively, the operation can be performed efficiently.

[0171] (Item B1) An electric work machine 1 comprising: a battery unit 30; an electric actuator (electric motor) 9 operated by power supplied by the battery unit 30; a work device 20 operated by driving the electric actuator 9; a plurality of temperature detection devices 31 b, 31 c, 31 d, 32 b, 32 c, 32 d that detect the temperature of the battery unit 30; a control device 7 that calculates a first temperature (temperature for display) T_show of the battery unit 30 based on the temperatures detected by the plurality of temperature detection devices 31 b, 31 c, 31 d, 32 b, 32 c, 32 d; and a display device 60 that displays the first temperature T_show calculated by the control device 7, wherein the control device 7 calculates the first temperature T_show based on a minimum temperature T_min and a maximum temperature T_max of the temperatures detected by the plurality of temperature detection devices 31 b, 31 c, 31 d, 32 b, 32 c, 32 d, and a weighting value that increases the weight of the minimum temperature as the minimum temperature is lower.

[0172] According to the invention related to item B1, the temperature of the battery unit 30 can be notified in a manner that is easily understandable to the worker. The worker can efficiently grasp the temperature of the battery unit 30.

[0173] (Item B2) The control device 7 is an electric work machine 1 described in item B1, in which if the minimum temperature T_min is less than a first predetermined value th1, the control device 7 sets the minimum temperature T_min as the first temperature T_show, if the minimum temperature T_min is equal to or greater than a second predetermined value th2, the control device 7 sets the maximum temperature T_max as the first temperature T_show, and if the minimum temperature T_min is equal to or greater than the first predetermined value th1 and less than the second predetermined value th2, the control device 7 calculates the first temperature T_show based on the minimum temperature T_min, the maximum temperature T_max, and a weighting value.

[0174] According to the invention relating to item B2, the displayed temperature value changes continuously while conforming to the charging characteristics of the battery unit 30, so the operator can grasp the temperature without feeling any discomfort.

[0175] (Item B3) An electric work machine 1 described in item B1 or B2, in which the first weighting value α, which is a weighting value multiplied by the minimum temperature T_min, increases as the minimum temperature T_min decreases, and the second weighting value 1-α, which is a weighting value multiplied by the maximum temperature T_max, increases as the minimum temperature T_min increases.

[0176] According to the invention related to item B3, the value of the first temperature T_show changes continuously without sudden changes, so that the operator can easily grasp the temperature of the battery unit 30.

[0177] (Item B4) The electric operating machine 1 according to any one of items B1 to B3, wherein the plurality of temperature detection devices 31b, 31c, 31d, 32b, 32c, and 32d are provided in different parts of the battery unit 30.

[0178] According to the invention related to item B4, even if there is a deviation in the temperature inside the battery unit 30, the temperature of the battery unit 30 can be accurately notified to the worker.

[0179] (Item B5) An electric work machine 1 described in items B1 to B4, wherein the battery unit 30 has a plurality of battery cells, and the plurality of temperature detection devices 31b, 31c, 31d, 32b, 32c, 32d are provided in different battery cells.

[0180] According to the invention related to item B5, even if there is a temperature imbalance among the plurality of battery cells included in the battery unit 30, the temperature of the battery unit 30 can be accurately notified to the worker.

[0181] (Item B6) An electric work machine 1 described in any one of items B1 to B5, wherein the control device 7 controls at least one of the charging current during charging and the discharging current during discharging of the battery unit 30 based on the minimum temperature T_min when the minimum temperature T_min is less than a first predetermined value th1, and controls at least one of the charging current and the discharging current based on the maximum temperature T_max when the maximum temperature T_max is equal to or greater than a second predetermined value th2.

[0182] According to the invention relating to item B6, charging and / or discharging suited to the temperature characteristics of the battery unit 30 becomes possible.

[0183] (Item B7) An electric work machine 1 described in any one of items B1 to B6, in which the control device 7 calculates a second temperature for controlling the battery unit 30 separately from the first temperature T_show, and controls at least one of the charging current when charging the battery unit 30 and the discharging current when discharging the battery unit 30 based on the second temperature.

[0184] According to the invention relating to item B7, by using different methods for calculating the temperature to be displayed on the display device 60 and the temperature used to control the electric work machine 1, it is possible to display information that is dominant in determining the charging time preferentially, thereby enabling the worker to easily determine the approximate charging time.

[0185] (Item B8) The upper limit values ​​of the charging current and discharging current are defined corresponding to the temperature of the battery unit 30, and the control device 7 calculates the temperature corresponding to the lower of the upper limit values ​​corresponding to the maximum temperature T_max and the minimum temperature T_min as the second temperature.

[0186] According to the invention relating to this item B8, charging and / or discharging that is more reliably suited to the temperature characteristics of the battery unit 30 is possible, whether the temperature of the battery unit 30 is relatively low or relatively high.

[0187] (Item B9) A control method for an electric work machine (1) comprising a battery unit (30), an electric actuator (electric motor) (9) operated by power supplied by the battery unit (30), a work machine (20) operated by driving the electric actuator (9), a plurality of temperature detection devices (31b, 31c, 31d, 32b, 32c, 32d) that detect the temperature of the battery unit (30), a display device (60) that displays the temperature of the battery unit (30), and a control device (7) that calculates a first temperature (T_show), which is the temperature to be displayed on the display device (60), the method including the steps of: identifying a minimum temperature (T_min) and a maximum temperature (T_max) among the temperatures detected by the plurality of temperature detection devices (31b, 31c, 31d, 32b, 32c, 32d; and calculating the first temperature (T_show) based on the minimum temperature (T_min), the maximum temperature (T_max), and a weighting value such that the weight of the minimum temperature (T_min) increases as the minimum temperature (T_min) decreases.

[0188] According to the invention related to item B9, the temperature of the battery unit 30 can be notified in a manner that is easily understandable to the worker. The worker can efficiently grasp the temperature of the battery unit 30.

[0189] Although the present invention has been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0190] In the above-described embodiment and modified examples, examples have been described in which the present invention is applied to an electric work machine 1 such as a backhoe, but the application of the present invention is not limited to this, and the present invention may also be applied to other construction machines such as wheel loaders, compact track loaders, and skid steer loaders, or agricultural machines such as tractors, combine harvesters, rice transplanters, and lawn mowers.

[0191] 1: Electric work machine 7: Control device 9: Electric actuator (electric motor) 20: Work device 30: Battery unit 31: Battery pack 31b: Temperature detection device 31c: Temperature detection device 31d: Temperature detection device 32: Battery pack 32b: Temperature detection device 32c: Temperature detection device 32d: Temperature detection device M1: First mode (standard mode) M2: Second mode (heat generation suppression mode) I_th1: First upper limit value (upper limit value of charging current) I_th2: Second upper limit value (upper limit value of discharging current) R1: First temperature range R2: Second temperature range B1: Switch (radio button) B2: Switch (radio button) B3: Switch (decision button)

Claims

1. An electric work machine comprising: a battery unit; an electric actuator operated by power supplied by the battery unit; a work device operated by driving the electric actuator; a temperature detection device that detects the temperature of the battery unit; and a control device that controls a first upper limit value, which is an upper limit value of a charging current supplied to the battery unit, in accordance with the temperature of the battery unit, wherein the control device is switchable between a first mode in which the charging current is controlled based on a first correspondence relationship that corresponds the temperature of the battery unit to the first upper limit value, and a second mode in which the charging current is controlled based on a second correspondence relationship in which the first upper limit value corresponding to at least a part of temperatures is lower than the first correspondence relationship.

2. The electric operating machine according to claim 1, wherein the control device lowers the first upper limit value as the temperature of the battery unit increases in each of the first mode and the second mode.

3. The electric work machine of claim 1, wherein the first upper limit value of the second mode in a predetermined first temperature range of the temperature of the battery unit is lower than the first upper limit value of the first mode in the first temperature range, and the first upper limit value of the second mode in a second temperature range in which the temperature of the battery unit is higher than the first temperature range is approximately equal to the first upper limit value of the first mode in the second temperature range.

4. An electric operating machine according to claim 3, wherein in at least one of the first mode and the second mode, the first upper limit value of the first temperature range is constant relative to the temperature of the battery unit.

5. The electric work machine according to claim 1, wherein the control device controls the output of the work device in accordance with the temperature of the battery unit.

6. An electric operating machine as described in claim 1, wherein the control device controls a second upper limit value, which is an upper limit value of the discharge current supplied from the battery unit to the electric actuator, in accordance with the temperature of the battery unit.

7. The electric operating machine according to claim 6, wherein the control device lowers the second upper limit value as the temperature of the battery unit increases.

8. An electric operating machine according to claim 1, further comprising a switch for switching between the first mode and the second mode.

9. A control method for an electric work machine including a battery unit, an electric actuator operated by power supplied by the battery unit, a work device operated by driving the electric actuator, a temperature detection device for detecting the temperature of the battery unit, and a control device for controlling charging of the battery unit, comprising: a first step of selecting either a first mode or a second mode; and a second step of controlling a first upper limit value that is an upper limit value of a charging current supplied to the battery unit in accordance with the mode selected in the first step and the temperature of the battery unit, wherein in the second step, if the first mode is selected, the charging current is controlled based on a first correspondence relationship that associates the temperature of the battery unit with the first upper limit value, and if the second mode is selected, the charging current is controlled based on a second correspondence relationship in which the first upper limit value corresponding to at least a part of temperatures is lower than the first correspondence relationship.

Images