electric shovel

Abstract

To improve charging speed of a battery.SOLUTION: An electric shovel has a lower traveling body, an upper turning body mounted on the lower traveling body, and a battery for supplying power so as to turn the upper turning body, and is configured to cool the battery using a predetermined cooling mechanism when the battery is charged from an external power source.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an electric shovel. [Background technology]

[0002] Conventionally, an electric shovel may be equipped with a battery that supplies power to a plurality of electric loads. In the electric shovel, the electric battery is charged by supplying power from an external charging facility. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-2160 Summary of the Invention [Problem to be solved by the invention]

[0004] When an electric excavator's battery is being charged from an external charging facility, the battery temperature rises due to the charging. The battery can also be cooled by natural air cooling. However, when the battery is rapidly charged, the battery temperature rises excessively with natural air cooling. An excessive rise in battery temperature causes battery degradation. To prevent battery degradation, when natural cooling is used, the battery charging speed must be reduced. This creates the problem of battery charging taking a long time.

[0005] In view of the above problems, an object of the present invention is to provide an excavator that can improve the charging speed by cooling the excavator during charging. [Means for solving the problem]

[0006] In order to achieve the above object, an electric shovel according to one embodiment of the present disclosure includes a lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, a battery that supplies power for rotating the upper rotating body, and a cabin mounted on the upper rotating body, a heater, and an air conditioner that extracts heat from the second liquid heated by the heater and adjusts the temperature inside the cabin;and configured to cool the battery using a predetermined cooling mechanism when the battery is being charged from an external power source. The predetermined cooling mechanism has a first flow path and is configured to cool the battery by exchanging heat with a first liquid circulating through the first flow path, and the heater heats a second liquid circulating through a second flow path different from the first flow path. The predetermined cooling mechanism further has a heat exchanger that exchanges heat between the first liquid circulating through the first flow path and the second liquid circulating through the second flow path, and is configured to start circulation through the second flow path when the temperature of the battery is higher than a first reference value, and the heat exchanger transfers heat from the first liquid, whose temperature has increased through heat exchange with the battery, to the second liquid. [Effects of the Invention]

[0007] According to the above-described embodiment, when the battery is being charged from an external power source, the battery is cooled using a predetermined cooling mechanism, thereby improving the charging speed of the battery without causing deterioration of the battery. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view showing a shovel (excavator) as an example of a construction machine according to an embodiment. [Figure 2] FIG. 2 is a block diagram schematically illustrating an example of the configuration of a shovel according to an embodiment. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of a battery cooling system and an air conditioning system mounted on the excavator according to the embodiment. [Figure 4] Fig. 4 is a diagram showing a flowchart illustrating processing performed by the battery controller and the shovel controller according to the embodiment. Fig. 4 is a diagram showing a flowchart illustrating processing performed by the battery controller and the shovel controller according to the embodiment. [Figure 5] FIG. 5 is a flowchart showing the processing performed by the air conditioning controller according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are merely examples and do not limit the invention, and all features and combinations described in the embodiments are not necessarily essential to the invention. In addition, identical or corresponding components in each drawing are designated by identical or corresponding reference numerals, and descriptions thereof may be omitted.

[0010] [Outline of the Excavator] First, with reference to FIG. 1, an outline of a shovel 200 as an example of an electric shovel will be described.

[0011] The excavator 200 of this embodiment comprises a lower running body 1, an upper rotating body 3 mounted on the lower running body 1 so as to be rotatable via a rotating mechanism 2, a boom 4, an arm 5, and a bucket 6 as attachments, and a cabin 10.

[0012] The lower traveling body 1 includes, for example, a pair of left and right crawlers, and is self-propelled by the crawlers being hydraulically driven by traveling hydraulic motors 1A, 1B (see FIG. 2).

[0013] The upper swing structure 3 is hydraulically driven by a swing hydraulic motor 2M (see FIG. 2) through the swing mechanism 2, thereby swinging relative to the undercarriage 1. All driven elements (for example, the swing hydraulic motor 2M) are hydraulically driven by hydraulic oil supplied from a main pump 14 (see FIG. 2). This corresponds to a configuration in which the power source (engine) of a so-called hydraulic excavator is replaced with a pump electric motor 12.

[0014] Furthermore, the upper rotating body 3 may be driven to rotate by a rotating electric motor driven by power supplied from the battery module 19, instead of the rotating hydraulic motor 2M. In this case, for example, the excavator 200 is connected to the rotating electric motor from the battery module 19 via the power conversion device 100 and an inverter. Then, under the control of the excavator controller 30 and the inverter, the rotating electric motor may perform a power running operation to drive the upper rotating body 3 to rotate, and a regenerative operation to generate regenerative power to brake the upper rotating body 3 to rotate. Furthermore, the rotating electric motor may supply the regenerative power to the battery module 19 and the pump electric motor 12 via an inverter.

[0015] A boom 4 is attached to the front center of the upper rotating body 3 so as to be able to tilt up and down, an arm 5 is attached to the tip of the boom 4 so as to be able to rotate up and down, and a bucket 6 is attached to the tip of the arm 5 so as to be able to rotate up and down. The boom 4, arm 5, and bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, which serve as hydraulic actuators, respectively.

[0016] The bucket 6 is an example of an end attachment, and other end attachments may be attached to the tip of the arm 5 instead of the bucket 6 depending on the type of work, etc. The other end attachments may be buckets of a different type from the bucket 6, such as a slope bucket or a dredging bucket. The other end attachments may also be end attachments of a different type from the bucket, such as a breaker, a mixer, a grapple, etc.

[0017] The cabin 10 is mounted on the front left side of the upper rotating body 3, and inside (inside) thereof, a cockpit where an operator sits, an operating device 26 (see FIG. 2) described later, and the like are provided.

[0018] In response to operations by an operator seated in a cabin 10, the excavator 200 operates driven elements such as a lower traveling body 1 (left and right crawlers), an upper rotating body 3, a boom 4, an arm 5, and a bucket 6.

[0019] Furthermore, instead of or in addition to being configured to be operable by an operator inside the cabin 10, the shovel 200 may be configured to be remotely operable from outside the shovel 200. When the shovel 200 is remotely operated, the inside of the cabin 10 may be unmanned. The following description will be given on the assumption that the operation of the operator includes at least one of the operation of the operating device 26 by the operator inside the cabin 10 and the remote operation by an external operator.

[0020] Remote control includes, for example, a mode in which the shovel 200 is operated by an operation input related to an actuator of the shovel 200 performed by a predetermined external device. In this case, the shovel 200 may be equipped with a communication device (not shown) capable of communicating with the predetermined external device, and may transmit image information (captured images) output by an imaging device (not shown) to the external device, for example. The external device may then display the received image information (captured images) on a display device (hereinafter referred to as a "display device for remote control") provided in the external device. Furthermore, various information images (information screens) displayed on the output device 50 (display device) inside the cabin 10 of the shovel 200 may also be displayed on the remote control display device of the external device. This allows the operator of the external device to remotely control the shovel 200 while checking the display contents of, for example, captured images and information screens showing the surroundings of the shovel 200 displayed on the display device for remote control. The excavator 200 may operate hydraulic actuators in response to a remote control signal indicating the content of the remote control, which is received from an external device by the communication device, to drive driven elements such as the lower traveling body 1 (left and right crawlers), upper rotating body 3, boom 4, arm 5, and bucket 6.

[0021] Furthermore, remote control may include, for example, a mode in which the shovel 200 is operated by an external voice input, gesture input, or the like to the shovel 200 by a person (e.g., a worker) around the shovel 200. Specifically, the shovel 200 recognizes voices uttered by surrounding workers or gestures made by the workers through a voice input device (e.g., a microphone) or a gesture input device (e.g., an imaging device) mounted on the shovel 200 (the shovel itself). Then, the shovel 200 may operate actuators in accordance with the content of the recognized voices, gestures, or the like to drive 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.

[0022] Furthermore, the shovel 200 may automatically operate the actuators regardless of the operation by the operator, thereby realizing a function (so-called "automatic driving function" or "machine control function") that automatically operates at least some of the driven elements such as the lower traveling structure 1 (crawlers 1CL, 1CR), upper rotating structure 3, boom 4, arm 5, and bucket 6.

[0023] The automatic driving function may include a function (so-called "semi-automatic driving function") that automatically operates driven elements (actuators) other than the driven element (hydraulic actuator) that is the target of operation, in response to an operator's operation of the operating device 26 or remote operation. The automatic driving function may also include a function (so-called "fully automatic driving function") that automatically operates at least some of the multiple driven elements (actuators) on the assumption that there is no operation of the operating device 26 or remote operation by the operator. When the fully automatic driving function is enabled in the shovel 200, the inside of the cabin 10 may be unmanned. The semi-automatic driving function, the fully automatic driving function, etc. may also include a mode in which the operation content of the driven element (actuator) that is the target of automatic driving is automatically determined in accordance with predetermined rules. The semi-automatic driving function, the fully automatic driving function, etc. may also include a mode in which the shovel 200 autonomously makes various decisions and autonomously determines the operation content of the driven element (actuator) that is the target of automatic driving in accordance with the decision results (so-called "autonomous driving function").

[0024] [Excavator configuration] Next, the configuration of a shovel 200 according to this embodiment will be described with reference to FIG. 2 in addition to FIG.

[0025] FIG. 2 is a block diagram that schematically shows an example of the configuration of a shovel 200 according to this embodiment.

[0026] In Figure 2, mechanical power lines are indicated by double lines, hydraulic lines by thick solid lines, pilot lines by dashed lines, and electric drive and control lines by thin solid lines.

[0027] <Hydraulic drive system> The hydraulic drive system of the excavator 200 according to this embodiment includes hydraulic actuators such as traveling hydraulic motors 1A, 1B, swing hydraulic motor 2M, boom cylinder 7, arm cylinder 8, and bucket cylinder 9, which hydraulically drive each of the driven elements such as the lower traveling structure 1, boom 4, arm 5, and bucket 6. The hydraulic drive system of the excavator 200 according to this embodiment also includes a pump electric motor 12, a main pump 14, and a control valve 17.

[0028] The pump electric motor 12 (an example of an electric actuator) is a power source for the hydraulic drive system. The pump electric motor 12 is, for example, an interior permanent magnet (IPM) motor. The pump electric motor 12 is connected to a high-voltage power supply including a battery module 19 and a power conversion device 100 via an inverter 18A. The pump electric motor 12 runs on three-phase AC power supplied from the battery module 19 via the inverter 18A, and drives the main pump 14 and the pilot pump 15. Drive control of the pump electric motor 12 may be performed by the inverter 18A under the control of a shovel controller 30, which will be described later.

[0029] The main pump 14 draws hydraulic oil from a hydraulic oil tank T and discharges it into a high-pressure hydraulic line 16, thereby supplying the hydraulic oil to a control valve 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by a pump electric motor 12. The main pump 14 is, for example, a variable displacement hydraulic pump, and a regulator (not shown) controls the angle (tilting angle) of the swash plate under the control of an excavator controller 30 (described later). This allows the main pump 14 to adjust the stroke length of the piston and thereby adjust the discharge flow rate (discharge pressure).

[0030] The main pump 14 may be driven by power from another power source in addition to the pump electric motor 12. For example, the main pump 14 may be driven by regenerating energy of hydraulic oil discharged from the boom cylinder 7 or arm cylinder 8 to a hydraulic oil tank due to the weight of the boom 4 or arm 5 when the boom 4 is lowered or the arm 5 is closed. Specifically, a hydraulic motor disposed coaxially with the rotation shaft of the main pump 14 may be driven by the energy of hydraulic oil discharged from the boom cylinder 7 or arm cylinder 8 to a hydraulic oil tank due to the weight of the boom 4 or arm 5 when the boom 4 is lowered or the arm 5 is closed. Furthermore, the energy of hydraulic oil discharged from the boom cylinder 7 or arm cylinder 8 to a hydraulic oil tank due to the weight of the boom 4 or arm 5 when the boom 4 is lowered or the arm 5 is closed may be regenerated to cause a generator to generate electricity. Specifically, the hydraulic motor arranged coaxially with the generator may be driven by the energy of hydraulic oil discharged from the boom cylinder 7 or the arm cylinder 8 into the hydraulic oil tank due to the weight of the boom 4 or the arm 5 when the boom 4 is lowered or the arm 5 is closed, thereby causing the generator to generate electricity. In this case, the generated power of the generator may be supplied to the pump motor 12 or may be used to charge the battery module 19.

[0031] The control valve 17 is a hydraulic control device that controls the hydraulic drive system in response to an operation command corresponding to an operator's operation or an automatic driving function. As described above, the control valve 17 is connected to the main pump 14 via the high-pressure hydraulic line 16, and is configured to be able to selectively supply hydraulic oil supplied from the main pump 14 to the hydraulic actuators (travel hydraulic motors 1A, 1B, swing hydraulic motor 2M, boom cylinder 7, arm cylinder 8, and bucket cylinder 9). For example, the control valve 17 is a valve unit including a plurality of control valves (directional switching valves) that control the flow rate and flow direction of hydraulic oil supplied from the main pump 14 to each of the hydraulic actuators. The hydraulic oil supplied from the main pump 14 and flowing through the control valve 17 and the hydraulic actuators is discharged from the control valve 17 to the hydraulic oil tank T.

[0032] <Electric drivetrain> The electric drive system of the shovel 200 according to this embodiment includes the pump motor 12, the sensor 12s, and the inverter 18A. The electric drive system of the shovel 200 according to this embodiment also includes a high-voltage power supply configured by a battery module 19, a power conversion device 100, etc.

[0033] The sensors 12s include a current sensor 12s1, a voltage sensor 12s2, and a rotation state sensor 12s3.

[0034] The current sensor 12s1 detects the current of each of the three phases (U phase, V phase, and W phase) of the pump motor 12. The current sensor 12s1 is provided, for example, on a power path between the pump motor 12 and the inverter 18A. Detection signals corresponding to the current of each of the three phases of the pump motor 12 detected by the current sensor 12s1 are directly input to the inverter 18A via a communication line. The detection signals may also be input to the shovel controller 30 via the communication line and input to the inverter 18A via the shovel controller 30.

[0035] The voltage sensor 12s2 detects the voltages applied to each of the three phases of the pump motor 12. The voltage sensor 12s2 is provided, for example, on a power path between the pump motor 12 and the inverter 18A. Detection signals corresponding to the voltages applied to each of the three phases of the pump motor 12 detected by the voltage sensor 12s2 are directly input to the inverter 18A via a communication line. The detection signals may also be input to the shovel controller 30 via the communication line and input to the inverter 18A via the shovel controller 30.

[0036] The rotation state sensor 12s3 detects the rotation state (for example, the rotation position (rotation angle), the rotation speed, etc.) of the pump motor 12. The rotation state sensor 12s3 is, for example, a rotary encoder or a resolver.

[0037] The inverter 18A drives and controls the pump motor 12 under the control of the shovel controller 30. The inverter 18A includes, for example, a conversion circuit that converts DC power into three-phase AC power and converts three-phase AC power into DC power, a drive circuit that switches and drives the conversion circuit, and a control circuit that outputs a control signal (for example, a PWM (Pulse Width Modulation) signal) that defines the operation of the drive circuit.

[0038] The control circuit of the inverter 18A controls the drive of the pump motor 12 while grasping the operating state of the pump motor 12. For example, the control circuit of the inverter 18A grasps 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 18A may grasp the operating state of the pump motor 12 by successively estimating the rotation angle of the rotating shaft of the pump motor 12, etc., based on the detection signal of the current sensor 12s1 and the detection signal of the voltage sensor 12s2 (or a voltage command value generated in the control process).

[0039] At least one of the drive circuit and the control circuit of the inverter 18A may be provided outside the inverter 18A.

[0040] The battery module 19 is configured to supply the charged power to electronic components in the shovel 200. The specific configuration will be described later.

[0041] The power conversion device 100 boosts the power of the battery module 19, or reduces the power from the pump motor 12 via the inverter 18A and stores the power in the battery module 19. The power conversion device 100 switches between a boost operation and a step-down operation depending on the operating state of the pump motor 12 so that the voltage value of a DC (Direct Current) bus 110 falls within a certain range. The control for switching between the boost operation and the step-down operation of the power conversion device 100 may be executed by the shovel controller 30 based on, for example, the detected voltage value of the DC bus 110, the detected voltage value of the battery module 19, and the detected current value of the battery module 19.

[0042] If there is no need to boost the output voltage of the battery module 19 and apply it to the pump motor 12, the power conversion device 100 may be omitted.

[0043] <Operation system> The operating system of the shovel 200 according to this embodiment includes a pilot pump 15, an operating device 26, and a pressure control valve 31.

[0044] The pilot pump 15 supplies pilot pressure to various hydraulic devices (e.g., pressure control valve 31) mounted on the shovel 200 via a pilot line 25. As a result, the pressure control valve 31 can supply pilot pressure to the control valve 17 according to the operation content (e.g., operation amount and operation direction) of the operating device 26 under the control of the shovel controller 30. Therefore, the shovel controller 30 and the pressure control valve 31 can realize the operation of the driven element (hydraulic actuator) according to the operation content of the operating device 26 by the operator. Furthermore, under the control of the shovel controller 30, the pressure control valve 31 can supply pilot pressure to the control valve 17 according to the remote operation content specified by the remote operation signal. The pilot pump 15 is, for example, a fixed displacement hydraulic pump, and is driven by the pump electric motor 12 as described above.

[0045] The operation device 26 is provided within reach of the operator in the driver's seat of the cabin 10 and is used by the operator to operate each driven element (i.e., the left and right crawlers of the undercarriage 1, the upper rotating body 3, the boom 4, the arm 5, the bucket 6, etc.). In other words, the operation device 26 is used by the operator to operate the hydraulic actuators that drive each driven element (e.g., the traveling hydraulic motors 1A and 1B, the swing hydraulic motor 2M, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, etc.). The operation device 26 is, for example, electric, and outputs an electric signal (hereinafter referred to as an "operation signal") corresponding to the operation content by the operator. The operation signal output from the operation device 26 is input to the excavator controller 30. As a result, the excavator controller 30 can control the pressure control valve 31 and control the operation of the driven elements (actuators) of the excavator 200 in accordance with the operation content of the operator and operation commands corresponding to the automatic driving function.

[0046] The operation device 26 includes, for example, levers 26A to 26C. The lever 26A may be configured to be able to receive operations related to the arm 5 (arm cylinder 8) and the upper rotating body 3 (swing operation) in accordance with operations in the front-rear direction and the left-right direction. The lever 26B may be configured to be able to receive operations related to the boom 4 (boom cylinder 7) and the bucket 6 (bucket cylinder 9) in accordance with operations in the front-rear direction and the left-right direction. The lever 26C may be configured to be able to receive operations related to the lower traveling body 1 (crawler), for example.

[0047] In addition, when the control valve 17 is configured as an electromagnetic pilot type control valve (directional control valve), an operation signal from the electric operating device 26 may be input directly to the control valve 17, and each hydraulic control valve may perform an operation according to the operation content of the operating device 26. Also, the operating device 26 may be of a hydraulic pilot type that outputs a pilot pressure according to the operation content. In this case, the pilot pressure according to the operation content is supplied to the control valve 17.

[0048] The pressure control valve 31 outputs a predetermined pilot pressure using hydraulic oil supplied from the pilot pump 15 through the pilot line 25 under the control of the excavator controller 30. The pilot line on the secondary side of the pressure control valve 31 is connected to the control valve 17, and the pilot pressure output from the pressure control valve 31 is supplied to the control valve 17.

[0049] <Control system> The control system of the shovel 200 according to this embodiment includes a shovel controller 30, an output device 50, and an input device 52.

[0050] The functions of the shovel controller 30 may be realized by any hardware or any combination of hardware and software. For example, the shovel controller 30 may be configured mainly with a computer including a processor such as a CPU (Central Processing Unit), a memory device (main storage device) such as a RAM (Random Access Memory), a non-volatile auxiliary storage device such as a ROM (Read Only Memory), and an interface device for input / output with the outside.

[0051] The shovel controller 30 controls the drive of the shovel 200. For example, the shovel controller 30 outputs a control command to the pressure control valve 31 in response to an operation signal input from the operating device 26, and causes the pressure control valve 31 to output a pilot pressure corresponding to the operation content of the operating device 26. In this way, the shovel controller 30 can realize the operation of the driven element (hydraulic actuator) of the shovel 200 corresponding to the operation content of the electric operating device 26.

[0052] Furthermore, when the shovel 200 is remotely operated, the shovel controller 30 may, for example, perform control related to the remote operation. Specifically, the shovel controller 30 may output a control command to the pressure control valve 31 and cause the pressure control valve 31 to output a pilot pressure according to the content of the remote operation. In this way, the shovel controller 30 can realize the operation of the shovel 200 (driven element) according to the content of the remote operation.

[0053] Furthermore, the shovel controller 30 may perform control relating to, for example, an automatic driving function. Specifically, the shovel controller 30 may output a control command to the pressure control valve 31, and cause the pressure control valve 31 to apply a pilot pressure corresponding to an operation command corresponding to the automatic driving function to the control valve 17. In this way, the shovel controller 30 can realize the operation of the driven element (hydraulic actuator) of the shovel 200 corresponding to the automatic driving function.

[0054] The shovel controller 30 may comprehensively control the operation of the entire shovel 200 (various devices mounted on the shovel 200).

[0055] The shovel controller 30 may control the air conditioning of the shovel 200 by communicating with the air conditioning controller 81. The shovel controller 30 may also control, for example, the operation and stop of a first water pump 91 of the battery cooling system 90. The shovel controller 30 may also control, for example, the operation and stop of a radiator 93 of the battery cooling system 90, which will be described later. The battery cooling system 90, the first water pump 91, and the radiator 93 will be described later.

[0056] The shovel controller 30 performs drive control of the electric drive system based on various input information (for example, control commands including operation signals from the operation device 26, etc.).

[0057] Furthermore, the shovel controller 30 may, for example, drive the power conversion device 100 based on the operation state of the operation device 26, and perform switching control between step-up operation and step-down operation of the power conversion device 100, in other words, between the discharged state and the charged state of the battery module 19. Furthermore, for example, when the shovel 200 is remotely operated, the shovel controller 30 may drive the power conversion device 100 based on the content of the remote operation, and perform switching control between the discharged state and the charged state of the battery module 19. Furthermore, for example, when the automatic operation function of the shovel 200 is enabled, the shovel controller 30 may drive the power conversion device 100 based on an operation command corresponding to the automatic operation function, and perform switching control between the discharged state and the charged state of the battery module 19.

[0058] The output device 50 is provided in the cabin 10, and outputs various types of information to the operator under the control of the shovel controller 30. The output device 50 includes, for example, a display device that outputs (notifies) information to the operator in a visual manner. The display device may be installed, for example, in a location that is easily visible to the operator in the cabin 10, and may display various information images under the control of the shovel controller 30. The display device is, for example, a liquid crystal display or an organic EL (Electroluminescence) display. The output device 50 also includes, for example, a sound output device that outputs information to the operator in an auditory manner. The sound output device is, for example, a buzzer, a speaker, etc.

[0059] The input device 52 is provided in the cabin 10 and accepts various inputs from the operator. The input device 52 may include, for example, an operation input device that accepts operation inputs from the operator. The operation input device includes, for example, a button, a toggle, a lever, a touch panel, a touchpad, etc. The input device 52 may also include, for example, a voice input device that accepts voice inputs from the operator and a gesture input device that accepts gesture inputs from the operator. The voice input device includes, for example, a microphone that captures the voice of the operator in the cabin 10. The gesture input device includes, for example, an indoor camera that can capture images of the operator's gestures in the cabin 10. A signal corresponding to the input from the operator accepted by the input device 52 is taken into the excavator controller 30.

[0060] <Battery peripheral configuration> 3 is a diagram showing an example of the configuration of a battery cooling system and an air conditioning system mounted on the shovel 200 according to this embodiment. Power cables are indicated by thin solid lines, signal lines by dotted lines, and flow paths for liquids (e.g., cooling water) by thick lines.

[0061] The shovel 200 includes, as components for charging the battery module 19, a normal charging vehicle inlet 101 and a rapid charging vehicle inlet 102.

[0062] Normal charging vehicle inlet 101 is configured to be connectable to a charging connector provided at the tip of a predetermined cable (hereinafter referred to as a "charging cable") of an external power source.

[0063] The on-board charger 103 converts AC power supplied from an external power source via the normal charging vehicle inlet 101 into DC power that can be charged into the battery 192 and supplies it to the battery module 19 .

[0064] The quick-charging vehicle inlet 102 is configured to be connectable to a charging connector provided at the tip of a charging cable from an external power source. The quick-charging vehicle inlet 102 is an inlet for performing quick charging based on, for example, CHAdeMO (registered trademark). In this embodiment, by using such a DC charging method, DC power can be supplied to the battery module 19 without going through an on-board charger (including, for example, an AC-DC converter).

[0065] The battery module 19 of the shovel 200 according to this embodiment supplies power to each component within the shovel 200.

[0066] The battery module 19 includes a battery controller 191 , a battery 192 , a PTC heater 193 , and a temperature sensor 194 .

[0067] The battery 192 supplies power to various components within the shovel 200. For example, the battery 192 supplies charged (stored) power to the pump motor 12 (see FIG. 2). The battery 192 may also be charged with power generated by the pump motor 12 (regenerated power).

[0068] The battery 192 is charged (stores electricity) by being connected to an external power source via a charging cable.

[0069] The battery 192 is, for example, a lithium ion battery, and has a relatively high output voltage (for example, several hundred volts).

[0070] The temperature sensor 194 detects the surface temperature of the battery 192 .

[0071] The PTC (Positive Temperature Coefficient) heater 193 is a type of electric heating wire heater, and controls heating of the battery 192 according to control from the battery controller 191.

[0072] The battery controller 191 (an example of a control unit) controls the internal configuration of the battery module 19. For example, the battery controller 191 monitors the temperature status of the battery 192 based on the surface temperature of the battery 192 detected by the temperature sensor 194. Furthermore, the battery controller 191 may perform control based on the temperature status of the battery 192.

[0073] For example, when charging the battery 192, charging efficiency tends to decrease when the temperature is low. Therefore, when the surface temperature of the battery 192 detected by the temperature sensor 194 is equal to or lower than a first threshold value (for example, 0 degrees), the battery controller 191 controls the PTC heater 193 to heat the battery 192, and then controls the battery to start charging.

[0074] When the battery controller 191 determines that it is connected to an external power source via a charging cable (in other words, when it determines that it is in a chargeable state), it communicates with a charging facility provided with the external power source. When the battery controller 191 is permitted to supply power from the charging facility through communication with the charging facility, charging from the external power source begins. Furthermore, the battery controller 191 may adjust the amount of power supplied from the external power source through communication with the charging facility.

[0075] Furthermore, the battery controller 191 may calculate the SOC (State Of Charge) of the battery 192 and perform control based on the calculated SOC.

[0076] For example, the battery controller 191 detects the SOC of the battery 192, and when it determines that the battery is fully charged, controls the battery 192 to end charging from an external power source through communication with a charging facility.

[0077] The battery controller 191 outputs the temperature state of the battery 192 detected by the temperature sensor 194 to the shovel controller 30. This allows the shovel controller 30 to control the battery cooling system 90 based on the temperature state of the battery 192.

[0078] <Battery cooling system> The battery cooling system 90 (an example of a predetermined cooling mechanism) includes a first water pump 91, a heat exchanger 92, and a radiator 93 (an example of a cooling device), as well as a first water circulation flow path 94 (an example of a first flow path) that forms a flow path through which coolant circulates. The battery cooling system 90 is a mechanism for cooling the battery 192 in the battery module 19, and, for example, cools the heat generated by the battery 192 when it is charged, etc.

[0079] Conventionally, batteries have tended to be cooled by natural air cooling. However, rapid charging of batteries is often performed, which has led to a demand for efficient cooling of batteries.

[0080] Therefore, the battery cooling system 90 according to this embodiment circulates the cooling water flowing through the first water circulation passage 94 based on the temperature detected by the temperature sensor 194 to cool the battery 192. This control makes it possible to efficiently cool the battery 192. Therefore, it is possible to improve charging efficiency and safety.

[0081] The first water circulation flow path 94 is a path for circulating the coolant between the first water pump 91, the battery 192 in the battery module 19, the heat exchanger 92, and the radiator 93.

[0082] The first water pump 91 circulates the cooling water within the first water circulation flow path 94 by sucking in and discharging the cooling water flowing from the first water circulation flow path 94 under the control of the shovel controller 30 .

[0083] The radiator 93 dissipates heat from the cooling water flowing through the first water circulation passage 94 in accordance with control from the shovel controller 30. By this control, the cooling water flowing through the first water circulation passage 94 can be cooled.

[0084] The radiator 93 is equipped with a water temperature sensor 93A. The water temperature sensor 93A detects the temperature of the cooling water flowing from the first water circulation passage 94 and transmits the detection result to the shovel controller 30.

[0085] The heat exchanger 92 is provided between the battery cooling system 90 and the heating system 80, and exchanges heat between the cooling water circulating through the first water circulation path 94 and the cooling water circulating through the second water circulation path 86.

[0086] When the battery 192 is being charged from an external power source, the shovel controller 30 performs control to cool the battery using a battery cooling system 90 (an example of a predetermined cooling mechanism).

[0087] Specifically, while the battery 192 is being charged from an external power source, the shovel controller 30 starts operation of the first water pump 91 when it determines that cooling of the battery 192 is necessary based on the detection results from the temperature sensor 194 in the battery module 19.

[0088] After starting the operation of the first water pump 91, the battery cooling system 90 cools the battery 192 by exchanging heat between the battery 192 and the coolant (an example of a first liquid) circulating through a first water circulation flow path 94 (an example of a first flow path). In this embodiment, an example will be described in which the battery 192 is cooled by a liquid-cooling method using the battery cooling system 90 (an example of a predetermined cooling mechanism). However, in this embodiment, the cooling mechanism for the battery 192 is not limited to a liquid-cooling cooling mechanism, and for example, an air-cooling cooling mechanism or the like may also be used.

[0089] Furthermore, if the shovel controller 30 determines based on the detection result from the temperature sensor 194 that the temperature of the battery 192 is greater than a first reference value (e.g., 25 degrees), the shovel controller 30 outputs a control signal to the air conditioning controller 81 to start circulating the cooling water in the second water circulation path 86.

[0090] When circulation of the cooling water in the second water circulation path 86 of the heating system 80 begins, the heat exchanger 92 transfers heat from the cooling water in the first water circulation path 94, whose temperature has increased due to heat exchange with the battery 192, to the cooling water in the second water circulation path 86.

[0091] Furthermore, if the shovel controller 30 determines that the temperature of the battery 192 is higher than a second reference value (for example, 35 degrees) based on the detection result from the temperature sensor 194 while the battery 192 is being charged, the shovel controller 30 determines that further cooling is necessary, and operates the radiator (specifically, the radiator fan) 93 provided on the first water circulation flow path 94. This enables further cooling of the battery 192.

[0092] The battery 192 can be appropriately cooled by the battery cooling system 90 described above. In this embodiment, an example is taken in which a heating system 80 is provided together with the battery cooling system 90. In this embodiment, the provision of a heat exchanger 92 enables heat exchange between the battery cooling system 90 and the heating system 80. Next, a specific configuration of the heating system 80 will be described.

[0093] <Heating system> The heating system 80 includes an air conditioning controller 81, a second water pump 82, a water heater 83, an HVAC 84, a three-way valve 85, and a heat exchanger 92, and is also formed with a second water circulation flow path 86 that forms a flow path through which the cooling water circulates. The heating system 80 is provided to heat the air inside the cabin 10.

[0094] The second water circulation flow path 86 is a flow path that circulates the coolant at least among the second water pump 82, the water heater 83, and the HVAC 84. Furthermore, by switching the three-way valve 85, the second water circulation flow path 86 can also include the heat exchanger 92 in the flow path that circulates the coolant.

[0095] The second water pump 82 circulates the cooling water within the second water circulation flow path 86 by sucking in and discharging the cooling water flowing from the second water circulation flow path 86 under the control of the air conditioning controller 81 .

[0096] The water heater 83 (an example of a heater) controls heating of the coolant flowing through the second water circulation flow path 86 (an example of a second flow path) under control of the air conditioning controller 81. The water heater may be any heater capable of heating the coolant. For example, a PTC heater may be used.

[0097] The water heater 83 is also provided with a water temperature sensor 83A. The water temperature sensor 83A detects the water temperature in the second water circulation passage 86 and outputs the result to the air conditioning controller 81.

[0098] The HVAC (Heating, Ventilation, and Air Conditioning) 84 (an example of an air conditioning device) is configured to adjust the state of air inside the cabin 10. The state of air is, for example, temperature or humidity. The HVAC 84 according to this embodiment is an apparatus unit that integrally includes devices for adjusting the state of air, such as a blower, a heat exchanger, and a humidifier.

[0099] For example, when the cooling water is circulating through the second water circulation path 86, the HVAC 84, under control of the air conditioning controller 81, extracts heat from the cooling water heated by the water heating heater 83 using a heat exchanger, thereby adjusting (e.g., raising) the temperature of the air inside the cabin 10.

[0100] The three-way valve 85 (an example of a switching valve) is a valve that switches between a first branch flow path 86A that passes through the heat exchanger 92 and a second branch flow path 86B that does not pass through the heat exchanger 92 (bypasses the heat exchanger 92), which are part of the second water circulation flow path 86. The switching of the flow paths by the three-way valve 85 is performed based on control from the air conditioning controller 81.

[0101] The air conditioning controller 81 controls the entire heating system 80. Specifically, the air conditioning controller 81 controls the HVAC 84, the second water pump 82, the water heater 83, and the three-way valve 85 in accordance with a control signal from the shovel controller 30 and the detection results of the water temperature sensors 84A and 83A.

[0102] For example, when the air conditioning controller 81 receives a control signal from the shovel controller 30 to circulate the cooling water in the second water circulation passage 86, it starts the operation of the second water pump 82. At that time, the air conditioning controller 81 controls the three-way valve 85 so that the cooling water circulates through the first branch passage 86A that passes through the heat exchanger 92. This starts heat exchange between the battery cooling system 90 and the heating system 80.

[0103] Incidentally, when an excavator is in a cold region (for example, at an air temperature of -20°C), the temperature of the cooling water (assumed to be antifreeze) flowing through the water circulation passage provided in the heating system is also low, just like the air temperature. In such a situation, when heating is performed using a water heater so that the HVAC can perform its heating function, it is necessary to raise the temperature of the cooling water from "-20°C" to around "80°C to 100°C." This heating control consumes a very large amount of power.

[0104] For example, if the cabin needs to be heated while the excavator is charging, it may take longer than normal charging if the power supplied from an external power source is divided between charging the battery and heating the cabin.

[0105] On the other hand, when charging a battery, the battery generates heat during charging, so it needs to be cooled. Typically, the heat generated by cooling the battery is treated as waste heat and tends to be released into the atmosphere, for example. As such, the heat generated by cooling the battery tends not to be used effectively.

[0106] As another example, in the case of an electric excavator that runs on power supplied from a battery, the battery capacity tends to be kept small compared to the operating time, and so quick charging is thought to be performed during spare time (for example, during the operator's break time). Because the current for quick charging is large, it is thought that the battery will generate more heat and generate a larger amount of exhaust heat. On the other hand, there is also a demand for heating the cabin before starting work during spare time (for example, during the operator's break time) even when the operator is not in the cabin.

[0107] Therefore, in this embodiment, a heat exchanger 92 is provided between the battery cooling system 90 and the heating system 80 to make effective use of heat.

[0108] For example, when the circulation of the cooling water through the second water circulation flow path 86 is started, the heat exchanger 92 transfers heat from the cooling water circulating through the first water circulation flow path 94 to the cooling water through the second water circulation flow path 86. This allows the cooling water circulating through the second water circulation flow path 86 to be raised to approximately the same temperature as the cooling water circulating through the first water circulation flow path 94 (for example, 40 degrees).

[0109] Even if the temperature of the cooling water circulating through the second water circulation path 86 reaches the temperature of the cooling water circulating through the first water circulation path 94 (e.g., 40 degrees), the temperature of the circulating cooling water needs to be further increased in order to heat using the HVAC 84.

[0110] Therefore, the air conditioning controller 81 transfers heat to the coolant passing through the first branch flow path 86A of the second water circulation flow path 86 using the heat exchanger 92, and then determines whether the temperature of the coolant (second liquid) detected by the water temperature sensor 84A or the water temperature sensor 83A is equal to or higher than a heating start threshold (e.g., 40°C). If the air conditioning controller 81 determines that the detected temperature of the coolant (second liquid) is equal to or higher than the heating start threshold, the air conditioning controller 81 controls the three-way valve 85 to switch the coolant from the first branch flow path 86A to the second branch flow path 86B. Furthermore, the air conditioning controller 81 controls the water heating heater 83 (an example of a heater) provided in the second water circulation flow path 86 to heat the coolant flowing through the second water circulation flow path 86. Note that in a low-temperature environment, the temperature of the coolant (second liquid) detected by the water temperature sensor 84A or the water temperature sensor 83A may not reach the heating start threshold. Even if the coolant temperature has not reached the heating start threshold, when a heating request is received through input from the input device 52 or the like, or when a condition for starting a heating operation calculated backward based on the temperature setting at the time of completion of charging is satisfied, the air conditioning controller 81 may control the three-way valve 85 to switch the coolant flow from the first branch flow path 86A to the second branch flow path 86B, and may also control the water heating heater 83 (an example of a heater) to heat the coolant flowing through the second water circulation flow path 86. Note that the condition for starting a heating operation calculated backward based on the temperature setting at the time of completion of charging is, for example, a condition for starting a heating operation to achieve a predetermined target temperature at the time of completion of charging (an example of a predetermined time) based on the temperature setting reserved by an operator. Note that a specific method for calculating the condition for starting a heating operation will not be described here, as it is a condition determined depending on the embodiment of the cabin 10 or the like.

[0111] By this control, the temperature of the cooling water flowing through the second water circulation passage 86 can be increased to about "80 to 100 degrees", and the inside of the cabin 10 can be heated by the HVAC 84.

[0112] By using the three-way valve 85, the air conditioning controller 81 controls the cooling water to circulate through the second branch flow path 86B and not circulate through the first branch flow path 86A, thereby preventing the heat of the cooling water heated by the water heater 83 from being taken into the battery cooling system 90. In other words, a decrease in the cooling efficiency of the battery 192 in the battery cooling system 90 can be prevented.

[0113] In this embodiment, the temperature of the battery 192 is raised to a temperature equivalent to that of the first water circulation flow path 94 based on the detection results from the temperature sensor 194, and then heating is performed using the water heating heater 83, thereby achieving efficient use of energy.

[0114] <Description of Processing When Power is Supplied from an External Power Supply According to the Embodiment> Next, a process performed when the shovel 200 according to this embodiment is supplied with power from an external power source will be described.

[0115] FIG. 4 is a diagram showing a flowchart illustrating the processing performed by the battery controller 191 and the shovel controller 30 according to this embodiment.

[0116] First, the battery controller 191 determines whether the charging cable is connected to an external power source from the normal charging vehicle inlet 101 or the quick charging vehicle inlet 102 (S401). If it determines that the charging cable is not connected to an external power source (S401: No), the battery controller 191 repeats this process until it determines that the charging cable is connected to an external power source.

[0117] If the battery controller 191 determines that the charging cable is connected to an external power supply from the normal charging vehicle inlet 101 or the quick charging vehicle inlet 102 (S401: Yes), it determines whether the temperature detected by the temperature sensor 194 is equal to or lower than a first threshold value (e.g., 0 degrees) (S402). If the battery controller 191 determines that the temperature detected by the temperature sensor 194 is higher than the first threshold value (S402: No), it performs the process of S406.

[0118] On the other hand, when the battery controller 191 determines that the temperature detected by the temperature sensor 194 is equal to or lower than the first threshold value (for example, 0 degrees) (S402: Yes), the battery controller 191 starts heating by the PTC heater 193 (S403).

[0119] That is, when the temperature of the battery 192 is low, the efficiency of charging the battery 192 decreases. Therefore, in this embodiment, control is performed so that charging starts after the battery 192 is warmed by the PTC heater 193. Note that the power supplied to the PTC heater 193 may come from the battery 192 or from an external power source.

[0120] Then, the battery controller 191 determines whether the temperature detected by the temperature sensor 194 is greater than a first threshold value (for example, 0 degrees) (S404). If it is determined that the temperature detected by the temperature sensor 194 is equal to or less than the first threshold value (S404: No), the battery controller 191 performs the process of S404 again after a predetermined time has elapsed.

[0121] On the other hand, when the battery controller 191 determines that the temperature detected by the temperature sensor 194 is greater than the first threshold value (for example, 0 degrees) (S404: Yes), it stops heating by the PTC heater 193 (S405).

[0122] Then, the battery controller 191 controls the battery 192 so that charging from the external power supply begins (S406).

[0123] Then, the battery controller 191 notifies the shovel controller 30 that charging has started (S407). After that, the battery controller 191 may transmit the temperature detected by the temperature sensor 194 to the shovel controller 30. This allows the shovel controller 30 to perform control according to the temperature of the battery 192.

[0124] Then, when it becomes necessary to cool the battery 192 (for example, when the temperature exceeds a reference temperature at which cooling is required), the shovel controller 30 starts the operation of the first water pump 91 (S408). The reference temperature is a value determined according to the state of the battery 192.

[0125] Then, the shovel controller 30 determines whether the temperature of the battery 192 detected by the temperature sensor 194 is greater than a first reference value (for example, 25 degrees) (S409). If the temperature of the battery 192 detected by the temperature sensor 194 is equal to or less than the first reference value (for example, 25 degrees) (S409: No), the shovel controller 30 performs the process of S409 again after a predetermined time has elapsed.

[0126] Then, when it is determined that the temperature of the battery 192 detected by the temperature sensor 194 is greater than a first reference value (for example, 25 degrees) (S409: Yes), the shovel controller 30 determines whether heating is set in the cabin 10 (S410). If heating is not set (S410: No), the shovel controller 30 performs the process of S412.

[0127] On the other hand, when it is determined that heating is set in the cabin 10 (S410: Yes), the shovel controller 30 outputs a control signal to the air conditioning controller 81 to circulate the cooling water in the second water circulation flow path 86 (S411). This starts the supply of heat to the heating system 80.

[0128] Thereafter, the shovel controller 30 determines whether the temperature of the battery 192 detected by the temperature sensor 194 is higher than a second reference value (e.g., 35 degrees) (S412). If the temperature of the battery 192 detected by the temperature sensor 194 is equal to or lower than the second reference value (S412: No), the process of S412 is performed again after a predetermined time. Note that the second reference temperature is set to a temperature higher than the first reference temperature.

[0129] On the other hand, if the shovel controller 30 determines that the temperature of the battery 192 detected by the temperature sensor 194 has exceeded a second reference value (e.g., 35 degrees) (S412: Yes), it controls the start of operation of the radiator (specifically, the radiator fan) 93 (S413).

[0130] 4 makes it possible to efficiently charge the battery 192 and appropriately cool the battery 192 during charging. Furthermore, it makes it possible to start the heating system 80 at an appropriate timing.

[0131] Next, the processing performed in the heating system 80 according to this embodiment will be described.

[0132] FIG. 5 is a flowchart showing the processing performed by the air conditioning controller 81 according to this embodiment.

[0133] The air conditioning controller 81 determines whether or not a control signal to circulate the cooling water in the second water circulation flow path 86 has been received from the shovel controller 30 (S501). If a control signal has not been received (S501: No), the process of S501 is repeated until a control signal is received.

[0134] When the air conditioning controller 81 receives a control signal to circulate the coolant in the second water circulation flow path 86 (S501: Yes), the air conditioning controller 81 starts operation of the second water pump 82 (S502). As a result, the heat of the coolant flowing in the first water circulation flow path 94 is transferred to the coolant flowing in the second water circulation flow path 86.

[0135] Thereafter, the air conditioning controller 81 determines whether a heating request has been received from the shovel controller 30 (input via the input device 52 or the like), and also determines whether the conditions for starting the heating operation, calculated backward from the temperature setting at the time of completion of charging, have been met (S503). If a heating request has not been received from the shovel controller 30 and it is determined that the conditions for starting the heating operation have not been met (S503: No), the process of S503 is repeated after a predetermined time has elapsed. Note that in S503, the determination may also be made based on whether the temperature is equal to or greater than the threshold for starting heating.

[0136] On the other hand, if the air conditioning controller 81 determines that it has received a heating request, or if it determines that the conditions for starting heating operation calculated backward from the temperature setting at the time of charging completion have been met (S503: Yes), it starts supplying power to the water heating heater 83, and starts heating the coolant with the water heating heater 83 (S504).

[0137] When the supply of power to water heater 83 is started, air conditioning controller 81 uses three-way valve 85 to circulate the cooling water through second branch flow path 86B and to control switching so that the cooling water does not circulate through first branch flow path 86A passing through heat exchanger 92 (S505). This control suppresses heat exchange between the cooling water flowing through first water circulation flow path 94 and the cooling water flowing through second water circulation flow path 86.

[0138] Thereafter, the air conditioning controller 81 determines whether the coolant temperature detected by the water temperature sensor 84A or the water temperature sensor 83A is greater than the heating start threshold (e.g., 80 degrees) (S506). If it is determined that the coolant temperature is equal to or less than the heating start threshold (S506: No), the air conditioning controller 81 performs the process of S506 again after a predetermined time.

[0139] Thereafter, if the air conditioning controller 81 determines that the temperature of the coolant detected by the water temperature sensor 84A or the water temperature sensor 83A is greater than the heating start threshold (e.g., 80 degrees) (S506: Yes), it controls the HVAC 84 to start heating (S507).

[0140] By using the processing procedure shown in Figure 5 to increase the water temperature in the second water circulation flow path 86 using the exhaust heat from the battery 192, and then further increasing the water temperature using the water heating heater 83, it is possible to improve energy efficiency when heating.

[0141] <effect> In the above-described embodiment, by configuring the battery to be cooled using the battery cooling system 90 (predetermined cooling mechanism), it is possible to suppress a rise in the temperature of the battery 192, for example, even when rapid charging of the battery 192 is performed. In other words, it is possible to improve the charging speed of the battery 192 while suppressing deterioration of the battery 192 due to a rise in temperature.

[0142] Furthermore, in the above-described embodiment, when the battery 192 is charged, the battery 192 is cooled by the battery cooling system 90, thereby achieving an efficient temperature reduction.

[0143] In this embodiment, when the timer is set to start charging and the timer is set to start heating, heat generated by charging the battery 192 can be used for heating.

[0144] In other words, when the heating system 80 is started, the heat generated by the cooling of the battery 192 by the battery cooling system 90 can be absorbed into the second water circulation path 86, thereby improving energy efficiency when heating.

[0145] Furthermore, when charging the battery 192 and heating the cabin 10, the water temperature in the second water circulation passage 86 can be increased to a certain level without supplying power from an external power source to the heating system 80, thereby shortening the charging time. In other words, the working time can be extended.

[0146] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0147] 200 Shovel 1 Undercarriage 2. Swivel mechanism 3 Upper rotating body 4. Boom 5 Arm 6 buckets 7 Boom cylinder 8 Arm Cylinder 9 Bucket cylinder 10 Cabins 30 Excavator Controller 19 Battery Module 191 Battery Controller 192 Battery 193 PTC heater 194 Temperature Sensor 80 Heating System 81 Air conditioning controller 82 No. 2 water pump 83 Water heater 83A Water Temperature Sensor 84 HVAC 84A Water Temperature Sensor 85 Three-way valve 86 Second Water Circulation Channel 86A First branch flow path 86B Second branch flow path 90 Battery Cooling System 91 No. 1 water pump 92 Heat exchanger 93 Radiator 93A Water Temperature Sensor 94 First Water Circulation Channel

Claims

1. a lower running body; an upper rotating body rotatably mounted on the lower traveling body; a battery that supplies power to rotate the upper rotating body; a cabin mounted on the upper rotating body; A heater; an air conditioning device that extracts heat from the second liquid heated by the heater and adjusts the temperature inside the cabin, The battery is cooled using a predetermined cooling mechanism when the battery is being charged from an external power source, the predetermined cooling mechanism has a first flow path and is configured to cool the battery by exchanging heat with a first liquid circulating through the first flow path; the heater heats the second liquid circulating through a second flow path different from the first flow path; the predetermined cooling mechanism further includes a heat exchanger that performs heat exchange between the first liquid circulating through the first flow path and the second liquid circulating through the second flow path, When the temperature of the battery is higher than a first reference value, circulation through the second flow path is started, and the heat exchanger is configured to transfer heat from the first liquid, the temperature of which has increased due to heat exchange with the battery, to the second liquid. Electric shovel.

2. the predetermined cooling mechanism further includes a cooling device provided in the first flow path to cool the first liquid, and when the temperature of the battery is greater than a second reference value that is a reference value higher than the first reference value, the cooling device is operated while heat is being transferred from the first liquid to the second liquid by the heat exchanger. The electric shovel according to claim 1 .

3. a switching valve configured to switch between a first branch flow path that passes through the heat exchanger and a second branch flow path that does not pass through the heat exchanger, as part of the second flow path; After the heat exchanger transfers heat from the first liquid to the second liquid, the switching valve is controlled to switch a part of the second flow path through which the second liquid flows from the first branch flow path to the second branch flow path, and the heater is used to heat the second liquid. The electric shovel according to claim 1 or 2.

Images