Electric power machinery

Abstract

This technology provides a way to reduce the power consumption of electric power machinery. [Solution] An excavator 100 according to one embodiment of the present disclosure comprises a lower traveling body 1, an upper rotating body 3 rotatably mounted on the lower traveling body 1, an attachment AT attached to the upper rotating body 3, a hydraulic actuator HA that drives the attachment AT, a power storage device 19 that is a power source for the hydraulic actuator HA, a heat transfer medium circuit 60 through which a heat transfer medium for adjusting the temperature of the power storage device 19 circulates, a hydraulic fluid circuit 80 that circulates hydraulic fluid for driving the hydraulic actuator, a heat exchanger 90 that performs heat exchange between the heat transfer medium of the heat transfer medium circuit 60 and the hydraulic fluid of the hydraulic fluid circuit 80, and a switching unit 65 that can switch between a first state in which heat exchange between the heat transfer medium of the heat transfer medium circuit 60 and the hydraulic fluid of the hydraulic fluid circuit 80 is possible using the heat exchanger 90, and a second state in which heat exchange between the heat transfer medium of the heat transfer medium circuit 60 and the hydraulic fluid of the hydraulic fluid circuit 80 is impossible using the heat exchanger 90.

Description

Technical Field

[0001] The present disclosure relates to a power-operated work machine.

Background Art

[0002] Conventionally, a power-operated work machine (for example, an electric excavator) equipped with a power storage unit (for example, a battery) as a power source for an actuator has been known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, it is desirable that the power storage unit be managed within a predetermined appropriate temperature range. Therefore, for example, in winter when the outside air temperature is low, the temperature of the power storage unit drops significantly below the appropriate temperature range, and it becomes necessary to warm the power storage unit with a heater or the like. As a result, the power consumption of the power-operated work machine increases, and the operating time of the electric excavator may be shortened. Therefore, in view of the above problems, an object is to provide a technology capable of suppressing the power consumption of a power-operated work machine.

Means for Solving the Problems

[0005] To achieve the above object, in one embodiment of the present disclosure, a main body portion, an attachment attached to the main body portion, a hydraulic actuator that drives the attachment, a power storage unit that is a power source for the hydraulic actuator, a heat medium circuit that circulates a heat medium for adjusting the temperature of the power storage unit, A hydraulic fluid circuit for circulating the hydraulic fluid that drives the hydraulic actuator, A first heat exchanger that performs heat exchange between the heat transfer medium of the heat transfer medium circuit and the hydraulic fluid of the hydraulic fluid circuit, The system includes a switching unit that can switch between a first state in which heat exchange is possible between the heat transfer medium of the heat transfer medium circuit and the hydraulic oil of the hydraulic oil circuit using the first heat exchanger, and a second state in which heat exchange is not possible between the heat transfer medium of the heat transfer medium circuit and the hydraulic oil of the hydraulic oil circuit using the first heat exchanger. Electric power machinery will be provided. [Effects of the Invention]

[0006] According to the above-described embodiment, the power consumption of electric power machinery can be suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] This is an external view showing an example of a shovel. [Figure 2] This is a diagram showing an example of the configuration of a shovel. [Figure 3] This figure shows an example of a heat transfer circuit and a hydraulic fluid circuit. [Figure 4] This flowchart schematically illustrates an example of control related to a heat transfer circuit. [Figure 5] This flowchart schematically illustrates an example of control related to a hydraulic fluid circuit. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings.

[0009] [Shovel Overview] Referring to Figure 1, an overview of the shovel 100 according to this embodiment will be described.

[0010] FIG. 1 is an external view showing an example of the excavator 100. Specifically, FIG. 1 is a side view showing an example of the excavator 100. Hereinafter, when explaining the direction in which the attachment AT extends in the top view of the excavator 100 (the upward direction in FIG. 2) as "front", the direction in the excavator 100 or the direction viewed from the excavator 100 may be described.

[0011] As shown in FIG. 1, the excavator 100 includes a lower traveling body 1, an upper revolving body 3, an attachment AT including a boom 4, an arm 5, and a bucket 6, and a cab 10.

[0012] The lower traveling body 1 uses a pair of left and right crawlers to move the excavator 100. The left and right crawlers are hydraulically driven by traveling hydraulic motors 1ML and 1MR (see FIG. 2), respectively. Thereby, the lower traveling body 1 can travel by itself.

[0013] The upper revolving body 3 is mounted on the lower traveling body 1 via a slewing mechanism 2 so as to be slewing freely. For example, the upper revolving body 3 can be slewed with respect to the lower traveling body 1 when the slewing mechanism 2 is hydraulically driven by a slewing hydraulic motor 2M.

[0014] The boom 4 is attached to the center of the front part of the upper revolving body 3 so as to be able to pitch around a rotation axis along the left-right direction. The arm 5 is attached to the tip of the boom 4 so as to be able to rotate around a rotation axis along the left-right direction. The bucket 6 is attached to the tip of the arm 5 so as to be able to rotate around a rotation axis along the left-right direction.

[0015] The bucket 6 is an example of an end attachment and is used, for example, in excavation work, slope work, leveling work, etc.

[0016] The bucket 6 is attached to the tip of the arm 5 in a manner that can be appropriately replaced according to the work content of the shovel 100. That is, instead of the bucket 6, a bucket of a different type from the bucket 6, for example, a relatively large large bucket, a bucket for a slope surface, a dredging bucket, etc. may be attached to the tip of the arm 5. Further, an end attachment of a type other than the bucket, for example, a stirrer, a breaker, a crusher, etc. may be attached to the tip of the arm 5. Also, a preliminary attachment such as a quick coupling or a tilt rotator may be provided between the arm 5 and the end attachment.

[0017] The boom 4, the arm 5, and the bucket 6 are each hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9.

[0018] In this example, as will be described later, the shovel 100 operates the pump motor 12 as a prime mover with the electric power supplied from the power storage device 19 as a power storage unit. Then, the hydraulic actuator HA is driven by the hydraulic oil supplied from the main pump 14 (see FIG. 2) driven by the pump motor 12, whereby all the driven elements are hydraulically driven. That is, in this example, the shovel 100 corresponds to a form in which the prime mover of a so-called hydraulic shovel, that is, an engine, is replaced with the pump motor 12, and the power storage device 19 as a power storage unit functions as a power source for the hydraulic actuator HA.

[0019] Note that part or all of the driven elements of the shovel 100 may be electrically driven. For example, the upper swing body 3 may swing with respect to the lower traveling body 1 by being electrically driven by a swing motor through the swing mechanism 2.

[0020] The cabin 10 is a cab for an operator to board and operate the shovel 100. The cabin 10 is mounted, for example, on the front left side of the upper swing body 3.

[0021] For example, the excavator 100 operates its driven elements, such as the lower travel body 1 (i.e., a pair of left and right crawlers), the upper slewing body 3, the boom 4, the arm 5, and the bucket 6, in response to the operation of an operator seated in the cabin 10.

[0022] Furthermore, instead of being configured to be operable by an operator sitting in the cabin 10, or in addition to being configured to be operable by an operator sitting in the cabin 10, the shovel 100 may also be configured to be remotely operated from outside the shovel 100. When the shovel 100 is remotely operated, the cabin 10 may be left unoccupied. Also, if the shovel 100 is for remote operation only, the cabin 10 may be omitted. The following explanation will proceed on the premise that operator operation includes at least one of operation of the operator's control device 26 in the cabin 10 and remote operation by an external operator.

[0023] For example, remote operation includes a mode in which the shovel 100 is operated by operation inputs related to the actuators of the shovel 100, which are performed by a remote operation support device capable of communicating with the shovel 100.

[0024] The remote control support device is installed, for example, in a control center that manages the operation of the shovel 100 from outside the work site. Alternatively, the remote control support device may be a portable control terminal, in which case the operator can remotely control the shovel 100 while directly checking the operation status of the shovel 100 from its vicinity.

[0025] The excavator 100 may, for example, transmit an image (hereinafter referred to as "surrounding image") representing the area in front of the excavator 100, based on an image output by an imaging device mounted on it, to the remote control support device via a communication device mounted on it. Alternatively, the excavator 100 may transmit an image output by the imaging device to the remote control support device via a communication device, and the remote control support device may process the image received from the excavator 100 to generate a surrounding image. The remote control support device may then display the surrounding image, including the area in front of the excavator 100, on its display device. Similarly, various information images (information screens) displayed on the output device 50 (display device) inside the cabin 10 may also be displayed on the display device of the remote control support device. This allows the operator using the remote control support device to remotely operate the excavator 100 while checking, for example, the displayed content of the image representing the area around the excavator 100 and information screens displayed on the display device. The shovel 100 may then operate actuators in response to remote control signals, which are received from a remote control support device via a communication device and represent the content of the remote control operation, thereby driving driven elements such as the lower traveling body 1, the upper slewing body 3, the boom 4, the arm 5, and the bucket 6.

[0026] Furthermore, remote operation may include, for example, a mode in which the shovel 100 is operated by external voice input or gesture input from people (e.g., workers) in the vicinity of the shovel 100. Specifically, the shovel 100 recognizes voices spoken or gestures made by surrounding workers through a voice input device (e.g., microphone) or gesture input device (e.g., imaging device) mounted on it. The shovel 100 may then operate actuators according to the content of the recognized voices or gestures to drive driven elements such as the lower traveling body 1 (left and right crawlers), the upper slewing body 3, the boom 4, the arm 5, and the bucket 6.

[0027] Furthermore, the excavator 100 may operate its actuators automatically, regardless of the operator's actions. This allows the excavator 100 to automatically operate at least some of its driven elements, such as the lower traveling body 1, the upper rotating body 3, and the attachment AT, thus realizing what is known as an "automatic driving function." This automatic driving function is also referred to as a "machine control (MC) function."

[0028] The automatic driving function includes, for example, a semi-automatic driving function. The semi-automatic driving function is also called an "operation-assistance type MC function." The semi-automatic driving function is a function that automatically operates driven elements (actuators) other than the target driven element (actuator) in response to the operator's operation. The automatic driving function may also include a fully automatic driving function. The fully automatic driving function is also called a "fully automatic type MC function." The fully automatic driving function is a function that automatically operates at least some of the multiple driven elements (hydraulic actuators) without operator intervention. In the case of the excavator 100, if the fully automatic driving function is enabled, the cabin 10 may be unoccupied. Also, if the excavator 100 is dedicated to fully automatic driving, the cabin 10 may be omitted. Furthermore, the semi-automatic driving function and the fully automatic driving function may also include, for example, a rule-based automatic driving function. The rule-based automatic driving function is an automatic driving function in which the operation content of the driven elements (actuators) that are the target of automatic driving is automatically determined according to predetermined rules. Furthermore, the semi-automatic driving function and the fully automatic driving function may also include an autonomous driving function. The autonomous driving function is an autonomous driving function in which the shovel 100 makes various decisions autonomously, and the operation of the driven elements (hydraulic actuators) that are the target of the autonomous driving is determined according to the results of those decisions.

[0029] Furthermore, the operation of the shovel 100 may be remotely monitored. In this case, a remote monitoring support device having the same functions as a remote operation support device may be provided. This allows the monitor, who is the user of the remote monitoring support device, to monitor the status of the shovel 100's operation while checking the surrounding image displayed on the display device of the remote monitoring support device. Also, for example, if the monitor deems it necessary from a safety standpoint, they can use the input device of the remote monitoring support device to make a predetermined input, thereby intervening in the operation or automatic operation of the shovel 100 by the operator and causing the shovel 100 to make an emergency stop.

[0030] [Shovel configuration] In addition to Figure 1, the configuration of the shovel 100 will be explained with reference to Figures 2 and 3.

[0031] Figure 2 shows an example of the configuration of the shovel 100. Figure 3 shows an example of the heat transfer medium circuit 60 and the hydraulic oil circuit 80. Figure 3 includes Figure 3A, which shows a state in which heat exchange between the heat transfer medium of the heat transfer medium circuit 60 and the hydraulic oil of the hydraulic oil circuit 80 is not possible through the heat exchanger 90, and Figure 3B, which shows a state in which heat exchange between the heat transfer medium of the heat transfer medium circuit 60 and the hydraulic oil of the hydraulic oil circuit 80 is possible through the heat exchanger 90.

[0032] In Figure 2, the paths through which mechanical power is transmitted are shown by double lines, the paths through which high-pressure hydraulic fluid that drives the hydraulic actuators are flowed are shown by thick solid lines, the paths through which pilot pressure is transmitted are shown by dashed lines, the paths through which electrical power is transmitted are shown by thin solid lines, and the paths through which electrical signals are transmitted are shown by dotted lines.

[0033] Excavator 100 includes components for a hydraulic drive system, an electric drive system, a power supply system, an operating system, a user interface system, and a control system.

[0034] <Hydraulic drive system> The hydraulic drive system of the Shovel 100 is a group of components related to the hydraulic drive of the driven element.

[0035] As shown in Figure 2, the hydraulic drive system of the excavator 100 includes a plurality of hydraulic actuators HA that drive each of the driven elements, such as the lower traveling body 1 (left and right crawlers), the upper rotating body 3, the boom 4, the arm 5, and the bucket 6, as described above. Furthermore, the hydraulic drive system of the excavator 100 according to this embodiment includes a pump motor 12, a main pump 14, a control valve 17, a hydraulic oil tank T, a hydraulic oil circuit 80, a heat exchanger 81, a fan 82, and a heat exchanger 90.

[0036] The multiple hydraulic actuators HA include travel hydraulic motors 1ML and 1MR, swing hydraulic motor 2M, boom cylinder 7, arm cylinder 8, and bucket cylinder 9, among others.

[0037] The pump motor 12 is the prime mover for the shovel 100. The pump motor 12 is, for example, an IPM (Interior Permanent Magnet) motor. The pump motor 12 is connected to the energy storage device 19 via an inverter 18. The pump motor 12 is powered by three-phase AC power supplied from the energy storage device 19 via the inverter 18, and drives the main pump 14 and the pilot pump 15. The drive control of the pump motor 12 may be performed by the inverter 18 under the control of a controller 30B, which will be described later.

[0038] Furthermore, in addition to the electric pump motor 12, an engine may also be installed as the prime mover for Shovel 100. In other words, Shovel 100 may be a so-called hybrid shovel.

[0039] The main pump 14 draws hydraulic fluid from the hydraulic fluid tank T and discharges it into the path 82A, which serves as a high-pressure hydraulic line, thereby supplying hydraulic fluid to the control valve 17 through the path 82A. The main pump 14 is driven by the pump motor 12 as described above. The main pump 14 is, for example, a variable displacement hydraulic pump, and under the control of the controller 30A (described later), a regulator (not shown) controls the angle (tilt angle) of the swash plate. This allows the main pump 14 to adjust the piston stroke length and thus adjust the discharge flow rate and discharge pressure.

[0040] The control valve 17 drives the hydraulic actuators HA in accordance with the operator's operation of the control device 26, the content of remote operation, or operation commands corresponding to the automatic operation function. The control valve 17 is mounted, for example, in the center of the upper rotating body 3. As described above, the control valve 17 is connected to the main pump 14 via the path 82A and selectively supplies hydraulic fluid supplied from the main pump 14 to each hydraulic actuator HA in accordance with the operator's operation or operation commands corresponding to the automatic operation function. Specifically, the control valve 17 may be a valve unit including a plurality of control valves (directional control valves) that control the flow rate and direction of the hydraulic fluid supplied from the main pump 14 to each of the hydraulic actuators HA. The hydraulic fluid supplied from the main pump 14 and that has passed through the control valve 17 and the hydraulic actuators is discharged from the control valve 17 to the hydraulic fluid tank T.

[0041] The hydraulic fluid tank T stores the hydraulic fluid used in the hydraulic drive system and operating system.

[0042] The hydraulic fluid circuit 80 is a circuit that circulates high-pressure hydraulic fluid supplied to the hydraulic actuator HA through the control valve 17. The hydraulic fluid circuit 80 includes paths 82A to 82E.

[0043] Route 82A connects the hydraulic oil tank T to the intake port of the main pump 14. Route 82B connects the discharge port of the main pump 14 to the hydraulic oil inlet of the control valve 17. In this way, the main pump 14 draws hydraulic oil from the hydraulic oil tank T through route 82A and discharges it through route 82B. Route 82C connects the hydraulic oil outlet of the control valve 17 to the inlet of the hydraulic oil flow path in the heat exchanger 90. In this way, the control valve 17 supplies hydraulic oil supplied from the main pump 14 through route 82B to the hydraulic actuator HA and discharges the hydraulic oil discharged from the hydraulic actuator HA through route 82C. Route 82D connects the outlet of the hydraulic oil flow path in the heat exchanger 90 to the hydraulic oil inlet of the heat exchanger 81. Route 82E connects the hydraulic oil outlet of the heat exchanger 81 to the hydraulic oil tank T.

[0044] The heat exchanger 81 is a so-called air-cooled oil cooler. The heat exchanger 81 cools the hydraulic oil by exchanging heat between the hydraulic oil flowing into its internal passages through path 82D and the surrounding air. The heat exchanger 81 discharges the cooled hydraulic oil into path 82E and returns it to the hydraulic oil tank T through path 82E.

[0045] Fan 82 is a blower that blows air toward the heat exchanger 81. This facilitates heat exchange through the heat exchanger 81, allowing the heat exchanger 81 to efficiently cool the hydraulic fluid. Fan 82 is powered by electricity supplied from at least one of the DC-DC converter 44 and the battery 46, under the control of the control device 30 (e.g., controller 30A).

[0046] The heat exchanger 90 is a so-called water-cooled oil cooler. The heat exchanger 90 cools the hydraulic oil and heats the heat transfer medium by exchanging heat between the hydraulic oil flowing in through path 82C and the heat transfer medium flowing in through path 67H, which will be described later.

[0047] <Electric drive system> The electric drive system of the Shovel 100 is a group of components related to the electric drive of the Shovel 100's prime mover and the electric drive of the driven elements.

[0048] As shown in Figure 2, the electric drive system of the shovel 100 includes a pump motor 12, a sensor 12s, and an inverter 18.

[0049] Furthermore, as described above, the electric drive system of the Shovel 100 may include an electric actuator that drives the driven elements and an inverter that drives the electric actuator when some or all of the driven elements are electrically driven.

[0050] Sensor 12s includes a current sensor 12s1, a voltage sensor 12s2, and a rotational state sensor 12s3.

[0051] The current sensor 12s1 detects the current of the pump motor 12. For example, the current sensor 12s1 detects the current of at least two of the three phases (U phase, V phase, and W phase) of the pump motor 12. This is because the detected value of the current of the remaining phase can be calculated from the detected values ​​of the currents of two phases. The current sensor 12s1 is installed, for example, in the power path between the pump motor 12 and the inverter 18. Alternatively, the current sensor 12s1 may be built into the inverter 18. The detection signal corresponding to the current of the pump motor 12 detected by the current sensor 12s1 is directly received by the inverter 18 via a communication line. Alternatively, the detection signal may be received by the controller 30B via a communication line and input to the inverter 18 via the controller 30B.

[0052] The voltage sensor 12s2 detects the voltage of the pump motor 12. For example, the voltage sensor 12s2 detects the applied voltage of each of the three phases of the pump motor 12. The voltage sensor 12s2 is installed, for example, in the power path between the pump motor 12 and the inverter 18. Alternatively, the voltage sensor 12s2 may be built into the inverter 18. The detection signals corresponding to the applied voltage of each of the three phases of the pump motor 12 detected by the voltage sensor 12s2 are directly received by the inverter 18 via a communication line. Alternatively, these detection signals may be received by the controller 30B via a communication line and input to the inverter 18 via the controller 30B.

[0053] The rotational state sensor 12s3 detects the rotational state of the pump motor 12. The rotational state of the pump motor 12 includes, for example, the rotational position (rotation angle) and rotational speed. The rotational state sensor 12s3 is, for example, a rotary encoder or a resolver. The detection signal corresponding to the rotational state of the pump motor 12 detected by the rotational state sensor 12s3 is directly received by the inverter 18 via a communication line. Alternatively, the detection signal may be received by the controller 30B via a communication line and input to the inverter 18 via the controller 30B.

[0054] The inverter 18 drives the pump motor 12 under the control of the controller 30B. The inverter 18 includes, for example, a conversion circuit that converts DC power to three-phase AC power and three-phase AC power to DC power, a drive circuit that switches and drives the conversion circuit, and a control circuit that outputs a control signal that defines the operation of the drive circuit. The control signal is, for example, a PWM (Pulse Width Modulation) signal.

[0055] The control circuit of the inverter 18 controls the drive of the pump motor 12 while understanding its operating state. For example, the control circuit of the inverter 18 understands the operating state of the pump motor 12 based on the detection signal of the rotation state sensor 12s3. Alternatively, the control circuit of the inverter 18 may understand the operating state of the pump motor 12 by sequentially estimating the rotation angle of the rotation shaft of the pump motor 12 based on the detection signal of the current sensor 12s1 and the detection signal of the voltage sensor 12s2 (or the voltage command value generated during the control process).

[0056] Furthermore, at least one of the drive circuit and control circuit of the inverter 18 may be provided outside the inverter 18.

[0057] <Power system> The power supply system of the Shovel 100 is a group of components that supply power to various electrical devices.

[0058] As shown in Figures 2 and 3, the power supply system of the shovel 100 includes a power storage device 19, a DC-DC converter 44, a battery 46, a heat transfer medium circuit 60, a reserve tank 61, a cooler 62, a heater 63, a pump 64, a switching unit 65, an on-board charger 70, and a charging port 72.

[0059] The energy storage device 19 is a power source for driving the actuator of the shovel 100 and has a relatively high output voltage (e.g., several hundred volts). The energy storage device 19 is charged (stored) by being connected to an external commercial power supply with a predetermined cable (hereinafter referred to as the "charging cable"), and supplies the charged (stored) power to the pump motor 12. The energy storage device 19 is, for example, a lithium-ion battery and constitutes the energy storage unit.

[0060] For example, the energy storage device 19 is constructed by stacking multiple energy storage modules vertically, with adjacent energy storage modules connected to each other by wire harnesses.

[0061] For example, an energy storage module includes multiple battery modules and a housing that houses them.

[0062] A battery module is an assembly composed of multiple battery cells (also called "unit batteries") connected in series.

[0063] For example, the enclosure is provided with a first space for housing battery modules and the like, and a second space corresponding to a flow path for a heat transfer medium for temperature control of the components of the energy storage module, such as the battery modules.

[0064] Furthermore, a power conversion device may be provided between the energy storage device 19 and the pump motor 12 to boost the output voltage of the energy storage device 19 and apply it to the pump motor 12. Also, as described above, when some or all of the driven elements are electrically driven, the power from the energy storage device 19 is supplied to an electric actuator that electrically drives the driven elements, either in place of or in addition to the pump motor 12.

[0065] The DC-DC converter 44 steps down the relatively high-voltage DC power output from the energy storage device 19 to a relatively low predetermined voltage (for example, about 24 volts) and outputs it. The output power of the DC-DC converter 44 is supplied to the battery 46 for charging (storage) or to electrical equipment (hereinafter referred to as "low-voltage equipment") powered by the battery 46. Low-voltage equipment includes, for example, various controllers included in the control device 30 (controllers 30A, 30B, 30C, 30D, etc.). Low-voltage equipment also includes, for example, the heater 63, pump 64, fan 82, etc., which will be described later. The DC-DC converter 44 is mounted, for example, on the upper rotating body 3.

[0066] Furthermore, the DC-DC converter 44 may be replaced with an alternator. In this case, the alternator may be installed on the upper rotating body 3 and generate electricity using the power of the pump motor 12. The power generated by the alternator is supplied to the battery 46, as in the case of the DC-DC converter 44, and is used to charge (store) the battery 46 or to supply power to low-voltage equipment.

[0067] The battery 46 has a relatively low output voltage (e.g., 24 volts) and supplies power to low-voltage devices other than the electric drive system that require relatively high power. The battery 46 is, for example, a lead-acid battery or a lithium-ion battery, and is charged by the output power of the DC-DC converter 44 as described above.

[0068] The heat transfer medium circuit 60 is a circuit that circulates a heat transfer medium to adjust the temperature of the energy storage device 19 through heat exchange with the energy storage device 19. The heat transfer medium is, for example, a coolant such as cooling water.

[0069] The heat transfer fluid circuit 60 includes paths 67A to 67I.

[0070] Route 67A connects the outlet of the heat transfer medium flow path inside the energy storage device 19 to the inlet of the pump 64. Route 67B connects the inlet of the pump 64 to port AP1 of the switching valve 65A. In this way, the pump 64 draws in the heat transfer medium through route 67A and discharges it through route 67B. Route 67C connects port AP2 of the switching valve 65A to port BP2 of the switching valve 65B. Route 67D connects port BP1 of the switching valve 65B to the heater 63. Route 67E connects the heater 63 to the reserve tank 61. Route 67F connects the reserve tank 61 to the cooler 62. Route 67G connects the cooler 62 to the inlet of the heat transfer medium flow path inside the energy storage device 19. Route 67H connects port AP3 of the switching valve 65A to the inlet of the heat transfer medium flow path in the heat exchanger 90. Route 67I connects the outlet of the heat transfer medium flow path in the heat exchanger 90 to port AP3 of the switching valve 65B.

[0071] The cooler 62 operates on power supplied from the energy storage device 19 or at least one of the DC-DC converter 44 and battery 46, and cools the heat transfer medium flowing in from the reserve tank 61 through path 67F and discharges it into path 67G. The cooler 62 is, for example, a chiller. Depending on the environment in which the shovel 100 is used, specifically the temperature range, the cooler 62 may also be a combination of a radiator and a fan that blows air onto the radiator.

[0072] The cooler 62 can be switched on or off under the control of the control device 30 (for example, controller 30A). This allows the control device 30 to activate the cooler 62 when cooling of the heat transfer medium is required, and to deactivate the cooler 62 when cooling of the heat transfer medium is not required. For example, if the cooler 62 is a chiller, deactivating the cooler 62 means that the chiller's refrigeration cycle is stopped. Also, for example, if the cooler 62 is a combination of a radiator and a fan, deactivating the cooler 62 means that the fan is stopped.

[0073] The heater 63 operates on power supplied from the energy storage device 19 or at least one of the DC-DC converter 44 and battery 46, heating the heat transfer medium flowing in through path 67D and causing it to flow out through path 67E. The heater 63 is, for example, an electric heater that operates on power supplied from the DC-DC converter 44 and battery 46.

[0074] The heater 63 can be switched on or off under the control of the control device 30 (for example, controller 30A). This allows the control device 30 to activate the heater 63 when heating of the heat transfer medium is required, and to deactivate the heater 63 when heating of the heat transfer medium is not required.

[0075] Pump 64 circulates the heat transfer medium in the heat transfer medium circuit 60 by drawing it in from path 67A and discharging it into path 67B.

[0076] The switching unit 65 uses the heat exchanger 90 to switch between a state in which heat exchange is possible between the heat transfer medium of the heat transfer medium circuit 60 and the hydraulic fluid of the hydraulic fluid circuit 80, and a state in which such heat exchange is not possible. In this example, the switching unit 65 switches between a state in which the heat transfer medium of the heat transfer medium circuit 60 passes through the heat exchanger 90 and a state in which the heat transfer medium of the heat transfer medium circuit 60 bypasses the heat exchanger 90. For example, as shown in Figure 3, the switching unit 65 includes switching valves 65A and 65B.

[0077] For example, as shown in Figure 3, the switching valves 65A and 65B are so-called three-way valves.

[0078] When the switching valve 65A is in a state where ports AP1 and AP2 are connected, and the switching valve 65B is in a state where ports BP1 and BP2 are connected, the heat transfer medium can pass through path 67C, bypassing paths 67H and 67I that would normally pass through the heat exchanger 90. On the other hand, when the switching valve 65A is in a state where ports AP1 and AP3 are connected, and the switching valve 65B is in a state where ports BP1 and BP3 are connected, the heat transfer medium can pass through paths 67H and 67I, allowing the heat transfer medium to pass through the heat exchanger 90. Hereinafter, the path passing through the heat exchanger 90, including paths 67H and 67I, may be conveniently referred to as the "heat recovery path".

[0079] The switching unit 65 switches the state of the switching valves 65A and 65B under the control of the control device 30 (for example, controller 30A). As a result, the control device 30 can bypass the heat exchanger 90 to the heat transfer medium by outputting control commands to the switching valves 65A and 65B so that they achieve the state shown in Figure 3A. Similarly, the control device 30 can pass the heat exchanger 90 to the heat transfer medium by outputting control commands to the switching valves 65A and 65B so that they achieve the state shown in Figure 3B.

[0080] Furthermore, the functions of the switching valves 65A and 65B may be replaced by on-off valves provided in each of the paths 67C, 67H, and 67I. In this case, when the on-off valve in path 67C is opened and the on-off valves in paths 67H and 67I are closed, the heat transfer medium can bypass the heat recovery path, and when the on-off valve in path 67C is closed and the on-off valves in paths 67H and 67I are opened, the heat transfer medium circuit can pass through the heat recovery path.

[0081] The onboard charger 70 converts a relatively low voltage (e.g., 100 volts or 200 volts) single-phase alternating current supplied from an external power source via the inlet 72A and wire harness 74 into direct current. The onboard charger 70 then outputs the converted direct current to the energy storage device 19 via the wire harness 76, thereby charging the energy storage device 19. The onboard charger 70 is mounted, for example, below the cabin 10 on the upper rotating body 3.

[0082] The charging port 72 is connected by inserting the end of a charging cable extending from an external power source.

[0083] For example, as shown in Figure 2, the charging port 72 includes inlets 72A and 72B.

[0084] The inlet 72A is configured to accept a charging cable extending from an external power source (e.g., commercial power) capable of supplying a relatively low-voltage single-phase AC power supply. The inlet 72A is connected to the onboard charger 70 by a wire harness 74, and supplies power from the external power source to the energy storage device 19 through the onboard charger 70. This enables so-called normal charging of the energy storage device 19.

[0085] The inlet 72B is configured to accept a charging cable extending from an external power source capable of supplying a relatively high voltage (e.g., 400 volts) of DC. The inlet 72B is directly connected to the energy storage device 19 by a wire harness 78, and the DC power supplied from the external power source is supplied directly to the energy storage device 19. This enables so-called rapid charging of the energy storage device 19.

[0086] For example, the inlets 72A and 72B are provided on the bottom surface of a recess that is set inward from the outer surface of the upper rotating body 3, and are covered by an openable and closable lid. This prevents water and foreign matter from adhering to the inlets 72A and 72B from the outside.

[0087] For example, as shown in Figure 1, the charging port 72 is located on the left side of the lower and central part in the front-rear direction of the upper rotating body 3. Specifically, the charging port 72 is located on the lower left side of the rear of the cabin 10 on the upper rotating body 3. Normally, the charging port 72 is kept covered by the lid 72C, but when charging the energy storage device 19, the user can expose the inlets 72A and 72B by opening the lid 72C.

[0088] <Operation system> The control system of the Shovel 100 consists of a group of components related to the operation of the driven element.

[0089] As shown in Figure 2, the operating system of the shovel 100 includes a pilot pump 15, an operating device 26, and a hydraulic control valve 31.

[0090] The pilot pump 15 supplies pilot pressure to various hydraulic devices (e.g., hydraulic control valve 31) mounted on the excavator 100 via the pilot line 25. This allows the hydraulic control valve 31, under the control of the controller 30A, to supply pilot pressure to the control valve 17 according to the operation of the operating device 26 (e.g., operation amount and direction). Therefore, the controller 30A and the hydraulic control valve 31 can realize the operation of the driven element (hydraulic actuator) according to the operation of the operating device 26 by the operator. Furthermore, under the control of the controller 30A, the hydraulic control valve 31 can supply pilot pressure to the control valve 17 according to the content of the remote operation specified by the remote operation signal. Additionally, under the control of the controller 30A, the hydraulic control valve 31 can supply pilot pressure to the control valve 17 according to the operation command corresponding to the automatic operation function. The pilot pump 15 is, for example, a fixed-displacement hydraulic pump, and as described above, is driven by the pump motor 12.

[0091] The pilot pump 15 may be omitted. In this case, hydraulic fluid discharged from the main pump 14 and reduced to a predetermined pilot pressure via a pressure reducing valve or the like may be supplied to various hydraulic devices such as the hydraulic control valve 31.

[0092] The control device 26 is located within reach of the operator in the cockpit of the cabin 10 and is used by the operator to operate each of the driven elements (i.e., the left and right crawlers of the lower traveling body 1, the upper slewing body 3, the boom 4, the arm 5, and the bucket 6, etc.). In other words, the control device 26 is used by the operator to operate the hydraulic actuators HA that drive each of the driven elements. For example, as shown in Figure 2, the control device 26 is electrically operated and outputs an electrical signal (hereinafter referred to as "operation signal") corresponding to the operator's operation. The operation signal output from the control device 26 is taken up by the controller 30A. As a result, the control device 30, including the controller 30A, controls the hydraulic control valve 31, etc., and can control the operation of the driven elements (actuators) of the shovel 100 in accordance with the operator's operation and operation commands corresponding to the automatic driving function.

[0093] The operating device 26 includes, for example, levers 26A to 26C. Lever 26A is configured to accept operations on the arm 5 (arm cylinder 8) and the upper slewing body 3 (slewing motion) in response to operations in the forward / backward and left / right directions, respectively. Lever 26B is configured to accept operations on the boom 4 (boom cylinder 7) and the bucket 6 (bucket cylinder 9) in response to operations in the forward / backward and left / right directions, respectively. Lever 26C is configured to accept operations on the lower traveling body 1 (crawler 1C), for example.

[0094] Furthermore, if the control valve 17 is composed of an electromagnetic pilot-operated hydraulic control valve (directional control valve), the operating signal from the electric operating device 26 may be directly input to the control valve 17, and each hydraulic control valve may perform an operation according to the operation of the operating device 26. Alternatively, the operating device 26 may be a hydraulic pilot type that outputs a pilot pressure according to the operation. In this case, the pilot pressure according to the operation is supplied to the control valve 17.

[0095] The hydraulic control valve 31 outputs a predetermined pilot pressure using hydraulic fluid supplied from the pilot pump 15 through the pilot line 25 under the control of the controller 30A. The pilot line on the secondary side of the hydraulic control valve 31 is connected to the control valve 17, and the pilot pressure output from the hydraulic control valve 31 is supplied to the control valve 17.

[0096] <User Interface System> The user interface system of Shovel 100 consists of a set of components related to the interaction between the user and Shovel 100.

[0097] As shown in Figure 2, the user interface system of the shovel 100 includes an operating device 26, an output device 50, and an input device 52.

[0098] The output device 50 outputs various information to the user of the shovel 100 (for example, the operator in the cabin 10 or an external remote operator) and people in the vicinity of the shovel 100 (for example, workers or drivers of work vehicles).

[0099] For example, the output device 50 includes lighting equipment and display devices that output various information in a visual manner. Lighting equipment is, for example, a warning light (indicator lamp). Display devices are, for example, liquid crystal displays and organic EL (electroluminescence) displays. For example, as shown in Figure 2, the lighting equipment and display devices may be installed inside the cabin 10 and output various information in a visual manner to the operator inside the cabin 10. Alternatively, the lighting equipment and display devices may be installed, for example, on the side of the upper rotating body 3 and output various information in a visual manner to workers around the shovel 100.

[0100] Furthermore, the output device 50 may include a sound output device that outputs various information in an audible manner. The sound output device may include, for example, a buzzer or a speaker. The sound output device may be provided, for example, inside and outside the cabin 10, and may output various information in an audible manner to the operator inside the cabin 10 or to people (workers, etc.) around the shovel 100.

[0101] Furthermore, the output device 50 may also include a device that outputs various types of information through tactile means such as vibrations in the cockpit.

[0102] The input device 52 receives various inputs from the user of the shovel 100, and the signals corresponding to the received inputs are taken into the controller 30A. For example, the input device 52 is installed inside the cabin 10 and receives inputs from operators inside the cabin 10. Alternatively, the input device 52 may be installed, for example, on the side of the upper rotating body 3 and receive inputs from workers around the shovel 100.

[0103] For example, the input device 52 includes an operation input device that accepts input from the user through mechanical operation. The operation input device may include a touch panel mounted on the display device, a touch pad installed around the display device, a button switch, a lever, a toggle, a knob switch provided on the operation device 26 (lever device), etc.

[0104] Furthermore, the input device 52 may include a voice input device that accepts voice input from the user. The voice input device may include, for example, a microphone.

[0105] Furthermore, the input device 52 may include a gesture input device that receives gesture input from the user. The gesture input device may include, for example, an imaging device that captures images of the gestures performed by the user.

[0106] Furthermore, the input device 52 may include a biometric input device that accepts biometric input from the user. Biometric input may include, for example, the input of biometric information such as the user's fingerprints or iris scan.

[0107] <Control System> The control system for Shovel 100 consists of a group of components related to the various controls of Shovel 100.

[0108] As shown in Figure 2, the control system of the shovel 100 includes a control device 30. The control system of the shovel 100 also includes a sensor 48 and temperature sensors 54, 56, and 58.

[0109] The control device 30 includes controllers 30A, 30B, 30C, and 30D. Hereinafter, controllers 30A, 30B, 30C, and 30D, or any one of them, may be conveniently referred to as "controller 30X".

[0110] Furthermore, some or all of the functions of controllers 30B, 30C, and 30D may be integrated into controller 30A. That is, the various functions realized by the control device 30 may be realized by one controller, or they may be realized in a distributed manner by two or three controllers as appropriate. In addition, the functions of controllers 30A to 30D may be further distributed and realized by five or more controllers.

[0111] The controller 30X may implement each function using arbitrary hardware, or any combination of hardware and software. For example, the controller 30X is centered around a computer including a CPU (Central Processing Unit), memory device, auxiliary storage device, and interface device. This allows the controller 30X to implement various functions, for example, by loading a program installed in the auxiliary storage device into the memory device and executing it on the CPU. The memory device is, for example, SRAM (Static Random Access Memory). The auxiliary storage device is, for example, EEPROM (Electrically Erasable Programmable Read Only Memory) or flash memory. The interface device includes, for example, a communication interface for communicating with other devices inside the shovel 100. The interface device may also include an external interface that allows data input and output to and from an external storage medium. This allows the interface device to install programs and various data that implement various functions from an external storage medium via the external interface.

[0112] Controller 30A works in conjunction with various controllers that make up the control device 30, including controllers 30B, 30C, and 30D, to control the drive of the shovel 100.

[0113] For example, the controller 30A outputs a control command to the hydraulic control valve 31 in response to the operation signal input from the operating device 26, causing the hydraulic control valve 31 to output a pilot pressure corresponding to the operation of the operating device 26. As a result, the controller 30A can realize the operation of the driven elements of the shovel 100 in accordance with the operation of the electric operating device 26.

[0114] Furthermore, for example, if the shovel 100 is remotely operated, the controller 30A performs control related to the remote operation. Specifically, the controller 30A may output a control command to the hydraulic control valve 31, causing the hydraulic control valve 31 to output a pilot pressure corresponding to the content of the remote operation. In this way, the controller 30A can realize the operation of the driven elements of the shovel 100 corresponding to the content of the remote operation.

[0115] Furthermore, for example, the controller 30A performs control related to the automatic driving function. Specifically, the controller 30A may output a control command to the hydraulic control valve 31 and cause the hydraulic control valve 31 to apply pilot pressure to the control valve 17 in accordance with the operation command corresponding to the automatic driving function. In this way, the controller 30A can realize the operation of the driven part (hydraulic actuator) of the shovel 100 that corresponds to the automatic driving function.

[0116] Furthermore, the controller 30A performs control related to the heat transfer medium circuit 60, for example. Specifically, the controller 30A may also perform control of the cooler 62, the heater 63, and the switching unit 65 (specifically, the switching valves 65A and 65B).

[0117] Furthermore, for example, controller 30A comprehensively controls the operation of the entire shovel 100 (specifically, the various devices mounted on the shovel 100) based on bidirectional communication with various controllers such as controllers 30B to 30D.

[0118] The controller 30B performs control of the electric drive system based on various information input from the controller 30A (for example, control commands including operation signals for the operating device 26).

[0119] The controller 30B, for example, outputs control commands to the inverter 18 to control the drive of the pump motor 12.

[0120] Furthermore, as described above, if a power converter is provided between the energy storage device 19 and the pump motor 12, the controller 30B may, for example, output control commands to the power converter and perform control over the operation of the power converter.

[0121] The controller 30C controls the energy storage device 19.

[0122] The controller 30C, for example, performs control related to the charging of the energy storage device 19.

[0123] The controller 30C monitors various states of the energy storage device 19 (e.g., current state, voltage state, temperature state, charge state, degradation state, presence or absence of abnormalities, etc.) based on the outputs of various sensors built into the energy storage device 19.

[0124] The controller 30D controls the DC-DC converter 44.

[0125] The controller 30D controls, for example, the operation of the DC-DC converter 44.

[0126] The controller 30D monitors various states of the DC-DC converter 44 (e.g., current state, voltage state, temperature state, etc.) based on the output of, for example, the sensor 48.

[0127] Sensor 48 measures the state of the power supplied to the low-voltage load from the DC-DC converter 44 and the battery 46. For example, sensor 48 may include a current sensor that measures the current supplied to the low-voltage load from the DC-DC converter 44 and the battery 46, and a voltage sensor that measures the voltage.

[0128] The temperature sensor 54 detects the temperature (cell temperature Tc) of the battery cells in the energy storage device 19. In this case, the temperature sensor 54 may be configured to detect the temperature of each of all the battery cells included in the energy storage device 19, or it may be configured to detect the temperature of only one or more of the battery cells. The temperature sensor 54 may also detect the temperature of an object that has a correlation with the cell temperature Tc (for example, the temperature of the heat transfer medium in the heat transfer medium circuit 60). The detection signal from the temperature sensor 54 is received by, for example, the controller 30A. This allows the controller 30A to understand the temperature state of the battery cells in the energy storage device 19.

[0129] The temperature sensor 56 detects the temperature (oil temperature To) of the hydraulic fluid in the hydraulic fluid circuit 80. The detection signal from the temperature sensor 56 is received by, for example, the controller 30A. This allows the controller 30A to understand the temperature state of the hydraulic fluid in the hydraulic fluid circuit 80.

[0130] The temperature sensor 58 detects the temperature of the heat transfer medium circulating in the heat transfer circuit 60. For example, the temperature sensor 58 detects the temperature of the cooling water (water temperature Tw) circulating in the heat transfer circuit 60. The following explanation will focus on the case where the temperature sensor 58 detects the water temperature Tw. The detection signal from the temperature sensor 58 is received by, for example, the controller 30A. This allows the controller 30A to understand the temperature state of the heat transfer medium in the heat transfer circuit 60.

[0131] [Control related to heat transfer fluid circuits] The control of the heat transfer fluid circuit 60 will be explained with reference to Figure 4.

[0132] Figure 4 is a flowchart illustrating a schematic example of control for the heat transfer fluid circuit 60.

[0133] The flowchart in Figure 4 is executed repeatedly at predetermined processing cycles, for example, while the shovel 100 is in operation. In this example, the flowchart in Figure 4 will be explained assuming that it is executed by the controller 30A of the control device 30.

[0134] As shown in Figure 4, in step S102, the controller 30A determines whether the cell temperature Tc of the energy storage device 19 is lower than the threshold Tc_th1. The threshold Tc_th1 corresponds, for example, to the lower limit of a predetermined appropriate temperature range for the cell temperature Tc.

[0135] For example, if the cell temperature Tc can be detected by the temperature sensor 54, the controller 30A determines whether the detected value of the cell temperature Tc is lower than the threshold Tc_th1. Also, for example, if the temperature sensor 54 detects the temperature of an object that is correlated with the cell temperature Tc, the controller 30A calculates an estimated value of the cell temperature Tc based on the value detected by the temperature sensor 54 and determines whether that estimated value is lower than the threshold Tc_th1. Furthermore, if the temperature sensor 54 detects the temperature of an object that is correlated with the cell temperature Tc, the controller 30A may determine whether the cell temperature Tc is lower than the threshold Tc_th1 by determining whether the detected value of the temperature sensor 54, which serves as a substitute value for the cell temperature Tc, is lower than a threshold predetermined in a manner corresponding to the threshold Tc_th1. The determination of the relationship between the cell temperature Tc and the threshold Tc_th2, described later, may also be performed in a similar manner.

[0136] The controller 30A proceeds to step S104 if the cell temperature Tc of the energy storage device 19 is lower than the threshold Tc_th1, and to step S112 otherwise.

[0137] In addition, in step S102, the controller 30A may determine whether the cell temperature Tc of the energy storage device 19 is less than or equal to the threshold Tc_th1.

[0138] In step S104, the controller 30A disables the cooler 62 (turns it OFF) and activates the heater 63 (turns it ON).

[0139] As a result, the controller 30A can heat the heat transfer medium (specifically, the coolant) with the heater 63 and heat the energy storage device 19, for example, when the cell temperature Tc is lower than the lower limit of the appropriate temperature range.

[0140] Specifically, if the cooler 62 is operating and the heater 63 is not operating (stopped), the controller 30A stops the cooler 62 and starts the heater 63. Also, if the cooler 62 is not operating (stopped) and the heater 63 is operating, the controller 30A causes the cooler 62 and heater 63 to maintain that state.

[0141] Once step S104 is complete, the controller 30A proceeds to step S106.

[0142] In step S106, the controller 30A determines, based on the detection signals from the temperature sensors 56 and 58, whether the oil temperature To of the hydraulic fluid circuit 80 is higher than the water temperature Tw of the heat transfer medium circuit 60. If the oil temperature To of the hydraulic fluid circuit 80 is higher than the water temperature Tw of the heat transfer medium circuit 60, the controller 30A proceeds to step S108; otherwise, it proceeds to step S110.

[0143] In step S108, the controller 30A controls the switching unit 65 to allow the heat transfer medium (cooling water in this example) to pass through the heat recovery path (i.e., paths 67H and 67I).

[0144] As a result, the controller 30A can heat the heat transfer medium (cooling water) in the heat exchanger 90 through heat exchange between the heat transfer medium and the hydraulic oil, which is at a higher temperature than the heat transfer medium. Therefore, the controller 30A can suppress the power consumption in the heater 63 required to raise the cell temperature Tc to an appropriate temperature range.

[0145] Specifically, when the switching unit 65 is in a state where the heat transfer medium bypasses the heat exchanger 90, that is, when the heat transfer medium passes through path 67C, the controller 30A switches the switching unit 65 (specifically, the switching valves 65A and 65B) to a state where the heat transfer medium passes through the heat recovery path. On the other hand, when the switching unit 65 is in a state where the heat transfer medium passes through the heat recovery path, the controller 30A causes the switching unit 65 to maintain that state.

[0146] Once step S108 is completed, the controller 30A terminates the processing of this flowchart.

[0147] In step S110, the controller 30A controls the switching unit 65 to cause the heat transfer medium (cooling water) to bypass the heat recovery path, that is, to pass through path 67C.

[0148] Specifically, when the switching unit 65 is in a state where the heat transfer medium passes through the heat recovery path, the controller 30A switches the switching unit 65 to a state where the heat transfer medium bypasses the heat recovery path, that is, to a state where it passes through path 67C. On the other hand, when the switching unit 65 is in a state where the heat transfer medium bypasses the heat recovery path, the controller 30A causes the switching unit 65 to maintain that state.

[0149] Once the process in step S110 is complete, the controller 30A terminates the process in this flowchart.

[0150] For simplicity, steps S106 and S110 may be omitted. In this case, the process of step S108 will be performed along with the process of step S104.

[0151] Meanwhile, in step S112, the controller 30A determines whether the cell temperature Tc is higher than the threshold Tc_th2 (>Tc_th1). The threshold Tc_th2 corresponds, for example, to the upper limit of a predetermined appropriate temperature range for the cell temperature Tc. Alternatively, the threshold Tc_th2 may be set to a value lower than that upper limit. If the cell temperature Tc is higher than the threshold Tc_th2, the controller 30A proceeds to step S114; otherwise, it proceeds to step S116.

[0152] In addition, in step S112, the controller 30A may determine whether the cell temperature Tc of the energy storage device 19 is equal to or greater than the threshold Tc_th2.

[0153] In step S114, the controller 30A activates (ON) the cooler 62 and deactivates (OFF) the heater 63, while also controlling the switching unit 65 to cause the heat transfer medium (cooling water) to bypass the heat recovery path, that is, to pass through path 67C.

[0154] As a result, the controller 30A can cool the heat transfer medium (cooling water) with the cooler 62 and cool the energy storage device 19, for example, when the cell temperature Tc is higher than the upper limit of an appropriate temperature threshold. In such a situation, the controller 30A can also use the heat exchanger 90 to perform heat exchange between the hydraulic oil in the hydraulic oil circuit 80 and the heat transfer medium (cooling water) in the heat transfer medium circuit 60, preventing the heat transfer medium from overheating.

[0155] Specifically, if the cooler 62 is inactive (stopped) and the heater 63 is active, the controller 30A activates the cooler 62 and stops the heater 63. Also, if the cooler 62 is active and the heater 63 is inactive (stopped), the controller 30A causes the cooler 62 and heater 63 to maintain that state.

[0156] Once step S114 is completed, the controller 30A terminates the processing of this flowchart.

[0157] Meanwhile, in step S116, the controller 30A disables both the cooler 62 and the heater 63, and controls the switching unit 65 to cause the heat transfer medium (cooling water) to bypass the heat recovery path, i.e., to pass through path 67C. This is because the cell temperature Tc is within an appropriate temperature range.

[0158] Specifically, if either the cooler 62 or the heater 63 is operating and the other is not operating, the controller 30A will stop the operation of one and cause the other to maintain that state. Also, if the cooler 62 and the heater 63 are in a non-operating (stopped) state, the controller 30A will cause the cooler 62 and the heater 63 to maintain that state.

[0159] Once the process in step S116 is complete, the controller 30A terminates the process in this flowchart.

[0160] [Control related to the hydraulic fluid circuit] Refer to Figure 5 to explain the control of the hydraulic fluid circuit.

[0161] Figure 5 is a flowchart illustrating a schematic example of control for the hydraulic fluid circuit 80.

[0162] The flowchart in Figure 5 is executed repeatedly at predetermined processing cycles, for example, while the shovel 100 is in operation. In this example, the flowchart in Figure 5 will be explained assuming that it is executed by the controller 30A of the control device 30.

[0163] As shown in Figure 5, in step S202, the controller 30A determines whether the oil temperature To of the hydraulic fluid circuit 80 is lower than the threshold To_th1 based on the detection signal from the temperature sensor 56. The threshold To_th1 is preset as a relatively high temperature within a range lower than the predetermined upper limit of the oil temperature To. If the oil temperature To of the hydraulic fluid circuit 80 is lower than the threshold To_th1, the controller 30A proceeds to step S204; otherwise, it proceeds to step S206.

[0164] In addition, in step S202, the controller 30A may determine whether the oil temperature To of the hydraulic fluid circuit 80 is less than or equal to the threshold To_th1.

[0165] In step S204, controller 30A disables fan 82 (turns it OFF).

[0166] Specifically, if fan 82 is operating, controller 30A will stop fan 82 from operating. Also, if fan 82 is already in a non-operating (stopped) state, controller 30A will cause fan 82 to maintain that state.

[0167] As a result, the controller 30A can slow down the cooling effect of the heat exchanger 81 on the oil temperature To, thereby promoting the rise in the oil temperature To. Therefore, the controller 30A can, for example, increase the rate at which the oil temperature To rises after the shovel 100 is started, and as a result, promote the heating of the heat medium in the heat medium circuit 60 through the heat exchanger 90 when the water temperature Tw is lower than the threshold Tw_th1. Thus, the controller 30A can further suppress the power consumption of the heater 63.

[0168] Once step S204 is completed, the controller 30A terminates the processing of this flowchart.

[0169] Meanwhile, in step S206, the controller 30A determines whether the oil temperature To of the hydraulic fluid circuit 80 is within the range of threshold To_th1 or greater and threshold To_th2 ​​(>To_th1) or less. Threshold To_th2 ​​corresponds, for example, to a predetermined upper limit of the oil temperature To. If the oil temperature To is within the above range, the controller 30A proceeds to step S208; otherwise, it proceeds to step S210.

[0170] Furthermore, in step S206, the controller 30A may determine whether the oil temperature To of the hydraulic fluid circuit 80 is greater than or equal to threshold To_th1 and less than threshold To_th2. Also, in step S202, if it is determined as described above whether the oil temperature To of the hydraulic fluid circuit 80 is less than or equal to threshold To_th1, the controller 30A determines whether the oil temperature To of the hydraulic fluid circuit 80 is higher than threshold To_th1 and less than or equal to threshold To_th2, or less than or equal to threshold To_th2.

[0171] In step S208, controller 30A sets fan 82 to rotate at a relatively low rotational speed N1.

[0172] As a result, the controller 30A can promote the cooling of the hydraulic fluid in the hydraulic fluid circuit 80 when the oil temperature To of the hydraulic fluid circuit 80 is somewhat close to the upper limit of what is permissible.

[0173] Specifically, if fan 82 is inactive (stopped), controller 30A activates fan 82 and rotates it at rotational speed N1. Also, if fan 82 is rotating at a relatively high rotational speed N2 (>N1), controller 30A reduces fan 82's rotational speed from N2 to N1. Furthermore, if fan 82 is rotating at rotational speed N1, controller 30A causes fan 82 to maintain that state.

[0174] Once step S208 is completed, the controller 30A terminates the processing of this flowchart.

[0175] Meanwhile, in step S210, the controller 30A causes the fan 82 to rotate at a relatively high rotational speed N2.

[0176] As a result, the controller 30A can promote the cooling of the hydraulic fluid in the hydraulic fluid circuit 80 when the oil temperature To exceeds the allowable upper limit. In addition, the controller 30A can increase the rotation speed of the fan 82 in accordance with the rise in oil temperature To. The controller 30A can operate the fan 82 efficiently and suppress the power consumption of the fan 82.

[0177] Specifically, if fan 82 is inactive (stopped), controller 30A activates fan 82 and makes it rotate at rotation speed N2. Also, if fan 82 is rotating at a relatively low rotation speed N1, controller 30A increases the rotation speed of fan 82 from N1 to N2. Furthermore, if fan 82 is rotating at rotation speed N2, controller 30A makes fan 82 maintain that state.

[0178] Once the process in step S210 is complete, the controller 30A terminates the process in this flowchart.

[0179] [Other embodiments] Other embodiments will be described.

[0180] The embodiments described above may be modified or altered as appropriate. Hereinafter, examples of modifications or alterations to the embodiments described above will be referred to as "modified versions" for convenience.

[0181] For example, in the above embodiment (specifically, Figure 5), the controller 30A controls the fan speed to increase or decrease in two stages in response to the rise or fall of the oil temperature To, but it may also be controlled to change the speed in three or more stages. Alternatively, the controller 30A may control the fan speed 82 to increase or decrease continuously in response to the rise or fall of the oil temperature To.

[0182] Furthermore, in the embodiments and their modifications described above, the heat transfer medium in the heat transfer medium circuit 60 is configured to bypass the heat exchanger 90. However, in addition to this configuration, or as an alternative, the hydraulic fluid in the hydraulic fluid circuit 80 may be configured to bypass the heat exchanger 90.

[0183] Furthermore, the configurations of the heat transfer medium circuit 60 and the hydraulic fluid circuit 80 of the above-described embodiments and their modified forms, and their control methods (specifically, Figures 4 and 5), may also be applied to the heat transfer medium circuit and hydraulic fluid circuit and their control methods of other electric power machines. Other electric power machines include, for example, electric wheel loaders. An electric wheel loader comprises, for example, a vehicle body, attachments mounted on the vehicle body including a boom, a bell crank, and a bucket, a hydraulic cylinder that drives the attachments, and a power storage device that is a power source for the hydraulic cylinders and can be charged by power supplied from an external power source.

[0184] [Effect] The operation of the electric power machine according to this embodiment will be described.

[0185] In the first aspect of this embodiment, the electric work machine comprises a main body, an attachment, a hydraulic actuator, a power storage unit, a heat transfer medium circuit, a hydraulic fluid circuit, a first heat exchanger, and a switching unit. The electric work machine is, for example, the excavator 100 described above. Alternatively, the electric work machine may be the electric wheel loader described above. The main body is, for example, the upper rotating body 3 of the excavator described above. Alternatively, the main body may be the vehicle body of the electric wheel loader described above. The attachment is, for example, the attachment AT described above. Alternatively, the attachment may include the boom, bell crank, and bucket in the electric wheel loader described above. The hydraulic actuator is, for example, the hydraulic actuator HA described above. The power storage unit is, for example, the power storage device 19 described above. The heat transfer medium circuit is, for example, the heat transfer medium circuit 60 described above. The hydraulic fluid circuit is, for example, the hydraulic fluid circuit 80 described above. The first heat exchanger is, for example, the heat exchanger 90 described above. Specifically, the attachment is mounted on the main body. The hydraulic actuator drives the attachment. The energy storage unit is the power source for the hydraulic actuator. The heat transfer medium circuit circulates a heat transfer medium to adjust the temperature of the energy storage unit. The hydraulic fluid circuit circulates hydraulic fluid to drive the hydraulic actuator. The first heat exchanger performs heat exchange between the heat transfer medium of the heat transfer medium circuit and the hydraulic fluid of the hydraulic fluid circuit. The switching unit can switch between a first state in which heat exchange is possible between the heat transfer medium of the heat transfer medium circuit and the hydraulic fluid of the hydraulic fluid circuit, and a second state in which heat exchange is not possible between the heat transfer medium of the heat transfer medium circuit and the hydraulic fluid of the hydraulic fluid circuit, using the first heat exchanger.

[0186] As a result, the electric power machine switches the switching mechanism to use the first heat exchanger to perform heat exchange between the heat transfer medium in the heat transfer medium circuit and the hydraulic oil in the hydraulic oil circuit, thereby heating the heat transfer medium and warming the low-temperature energy storage unit. Therefore, the electric power machine can suppress power consumption when warming the low-temperature energy storage unit.

[0187] Furthermore, in a second aspect of this embodiment, based on the first aspect described above, the switching unit may switch to the first state when the temperature of the energy storage unit is below a first threshold, or lower than the first threshold. The first threshold is, for example, the threshold Tc_th1 described above.

[0188] As a result, the electric power machine can warm the power storage unit by using the first heat exchanger to perform heat exchange between the heat transfer medium in the heat transfer medium circuit and the hydraulic oil in the hydraulic oil circuit, under conditions where the temperature of the power storage unit is relatively low.

[0189] Furthermore, in a third aspect of this embodiment, based on the second aspect described above, the switching unit may switch to the first state when the temperature of the energy storage unit is below or below the first threshold, or lower than the first threshold, and the temperature of the hydraulic fluid in the hydraulic fluid circuit is equal to or higher than the temperature of the heat transfer medium in the heat transfer medium circuit, or higher than the temperature of the heat transfer medium in the heat transfer medium circuit.

[0190] As a result, the electric power machine can warm the power storage unit by using the first heat exchanger to perform heat exchange between the heat transfer medium in the heat transfer medium circuit and the hydraulic oil in the hydraulic oil circuit, under conditions where the temperature of the power storage unit is relatively low and the temperature of the hydraulic oil is higher than that of the heat transfer medium.

[0191] Furthermore, in a fourth aspect of this embodiment, based on any one of the first to third aspects described above, the electric work machine may include a second heat exchanger provided in the hydraulic fluid circuit for performing heat exchange between the hydraulic fluid in the hydraulic fluid circuit and the surrounding air, and a fan for blowing air toward the second heat exchanger. The second heat exchanger is, for example, the heat exchanger 81 described above. The fan is, for example, the fan 82 described above. Specifically, the fan does not need to operate if the temperature of the hydraulic fluid in the hydraulic fluid circuit is below a second threshold, or lower than the second threshold. The second threshold is, for example, the threshold To_th1 described above.

[0192] This allows the electric power machine to increase the rate at which the hydraulic fluid rises in the hydraulic fluid circuit after it starts up. As a result, the electric power machine can promote heat exchange between the hydraulic fluid in the hydraulic fluid circuit and the heat transfer medium in the heat transfer medium circuit through the first heat exchanger, and heat the energy storage unit more efficiently. Therefore, the electric power machine can suppress power consumption when heating the low-temperature energy storage unit.

[0193] Furthermore, in a fifth aspect of this embodiment, based on the fourth aspect described above, the fan may operate when the temperature of the hydraulic fluid in the hydraulic fluid circuit is higher than or equal to the second threshold. The rotational speed of the fan may be higher when the hydraulic fluid in the hydraulic fluid circuit is at a second temperature higher than the first temperature than when it is at a first temperature, within the range where the temperature of the hydraulic fluid in the hydraulic fluid circuit is higher than or equal to the second threshold. The first temperature is, for example, the temperature in the temperature range between the threshold To_th1 and the threshold To_th2 ​​described above. The second temperature is, for example, the temperature in the temperature range higher than the threshold To_th2 ​​described above.

[0194] This allows the electric power machine to increase or decrease the fan speed in accordance with the rise or fall of the oil temperature in the hydraulic fluid circuit. As a result, the electric power machine can operate the fan efficiently and reduce the fan's power consumption.

[0195] Furthermore, in a sixth aspect of this embodiment, based on any one of the first to fifth aspects described above, the heat transfer medium circuit may include a first path through which the heat transfer medium passes the first heat exchanger, and a second path through which the heat transfer medium bypasses the first heat exchanger. The first path is, for example, the paths 67H and 67I described above. The second path is, for example, the path 67C described above. The switching unit may be able to switch between a first state in which the heat transfer medium passes through the first path and a second state in which the heat transfer medium passes through the second path.

[0196] As a result, the electric power machine can switch between a state in which heat exchange between the heat transfer medium and the hydraulic oil is possible and an impossible state by switching between a state in which the heat transfer medium passes through the first heat exchanger and a state in which the heat transfer medium bypasses the first heat exchanger.

[0197] Although embodiments have been described in detail above, this disclosure is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0198] 1. Lower running body 1C Crawler 1ML, 1MR Hydraulic Motor for Travel 2. Swivel mechanism 2M Swivel Hydraulic Motor 3. Upper rotating body 4 Boom 5 Arms 6 buckets 7 Boom Cylinder 8 Arm Cylinder 9 Bucket Cylinder 10 cabins 12 Electric motors for pumps 12s sensor 12s1 Current Sensor 12s2 Voltage Sensor 12s3 Rotation status sensor 14 Main pump 15 Pilot pump 17 Control valve 18 Inverters 19. Energy storage device 25 Pilot Line 26 Operating device 26A~26C Lever 30 Control device 30A~30D Controller 31 Hydraulic control valve 44 DC-DC converters 46 batteries 48 sensors 50 Output device 52 Input devices 54 Temperature Sensor 56 Temperature Sensor 58 Temperature Sensor 60 Heat carrier circuit 61 Reserve Tank 62 Cooler 63 Heater 64 pumps 65 Switching section 65A, 65B switching valve Route 67A~67I 70 On-board charger 72 Charging port 72A Inlet 72B Inlet 72C Lid 74 Wire Harness 76 Wire Harness 78 Wire Harness 80. Hydraulic fluid circuit 81 Heat exchanger 82 Fans Route 82A~82E 90 Heat exchanger 100 Shovel AP1~AP3 Ports AT attachment BP1~BP3 Ports HA Hydraulic Actuator T Hydraulic oil tank

Claims

1. The main body and An attachment to be attached to the main body, A hydraulic actuator that drives the aforementioned attachment, The power storage unit is the power source for the hydraulic actuator, A heat transfer circuit for circulating a heat transfer medium to adjust the temperature of the energy storage unit, A hydraulic fluid circuit for circulating the hydraulic fluid that drives the hydraulic actuator, A first heat exchanger that performs heat exchange between the heat transfer medium of the heat transfer medium circuit and the hydraulic fluid of the hydraulic fluid circuit, The system includes a switching unit that can switch between a first state in which heat exchange is possible between the heat transfer medium of the heat transfer medium circuit and the hydraulic fluid of the hydraulic fluid circuit using the first heat exchanger, and a second state in which heat exchange is not possible between the heat transfer medium of the heat transfer medium circuit and the hydraulic fluid of the hydraulic fluid circuit using the first heat exchanger. Electric power machinery.

2. The switching unit switches to the first state when the temperature of the energy storage unit is below a first threshold, or is lower than the first threshold. The electric work machine according to claim 1.

3. The switching unit switches to the first state when the temperature of the energy storage unit is below a first threshold, or lower than the first threshold, and the temperature of the hydraulic fluid in the hydraulic fluid circuit is equal to or higher than the temperature of the heat transfer medium in the heat transfer medium circuit, or higher than the temperature of the heat transfer medium in the heat transfer medium circuit. The electric work machine according to claim 2.

4. A second heat exchanger is provided in the hydraulic fluid circuit and performs heat exchange between the hydraulic fluid of the hydraulic fluid circuit and the surrounding air, The system comprises a fan that blows air toward the second heat exchanger, The fan does not operate if the temperature of the hydraulic fluid in the hydraulic fluid circuit is below a second threshold, or if it is lower than the second threshold. An electric work machine according to any one of claims 1 to 3.

5. The fan operates when the temperature of the hydraulic fluid in the hydraulic fluid circuit is higher than the second threshold, or equal to or greater than the second threshold. The rotational speed of the fan is higher when the temperature of the hydraulic fluid in the hydraulic fluid circuit is higher than the second threshold, or within the range where the temperature of the hydraulic fluid in the hydraulic fluid circuit is above the second threshold, than when the hydraulic fluid in the hydraulic fluid circuit is at the first temperature. The electric work machine according to claim 4.

6. The heat transfer medium circuit includes a first path through which the heat transfer medium passes the first heat exchanger, and a second path through which the heat transfer medium bypasses the first heat exchanger. The switching unit is capable of switching between a first state in which the heat transfer medium passes through the first path and a second state in which the heat transfer medium passes through the second path. An electric work machine according to any one of claims 1 to 3.

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