Working machinery

Abstract

To provide a work machine that can facilitate maintenance of a battery unit.SOLUTION: A work machine comprises: a battery unit; piping which is connected to the battery unit and through which a heat exchange medium flows; and a heat exchanger to which the piping is connected. The heat exchanger is disposed on the opposite side to a connection side to the piping in the battery unit, with respect to the battery unit.SELECTED DRAWING: Figure 5

Description

Technical Field

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[0001] The present invention relates to a working machine.

Background Art

[0002] Conventionally, an electric hydraulic excavator in which a plurality of air-cooled battery units are arranged in a box has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration for air-cooling the battery unit, it is difficult to adjust (for example, cool) the temperature of the battery unit to an appropriate temperature range in a short time. For this reason, in recent years, as a cooling method for the battery unit, a water-cooling method using a heat exchange medium such as cooling water has been widely adopted. By providing a pipe for circulating the heat exchange medium between a heat exchanger such as a radiator and the battery unit, the battery unit can be cooled to an appropriate temperature in a short time.

[0005] [[ID=D39]]However, when the water-cooling method is adopted, for example, if the connection part of the battery unit with the pipe is located on the heat exchanger side, when performing maintenance such as inspection of the above connection part, the presence of the heat exchanger may make the above maintenance difficult. <00000SO> The present invention has been made to solve the above problems, and an object thereof is to provide a working machine that can facilitate maintenance of a battery unit.

Means for Solving the Problems

[0007] A working machine according to one aspect of the present invention comprises a battery unit, piping connected to the battery unit through which a heat exchange medium flows, and a heat exchanger to which the piping is connected, wherein the heat exchanger is positioned on the side of the battery unit opposite to the side of the battery unit to which the piping is connected. [Effects of the Invention]

[0008] The above configuration makes it easier to perform maintenance on the battery unit. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view showing the schematic configuration of a hydraulic excavator, which is an example of an electric work machine according to one embodiment of the present invention. [Figure 2] This is a schematic block diagram showing the electrical and hydraulic system configurations of the above-mentioned hydraulic excavator. [Figure 3] This is a perspective view showing the internal configuration of the engine room of the hydraulic excavator described above. [Figure 4] This is a perspective view of the main parts of the engine room, seen from the right rear. [Figure 5] This is a perspective view of the main parts shown above, taken from the left rear. [Figure 6] This is a plan view of the main part shown above. [Figure 7] This is a perspective view showing another example of piping arrangement in the hydraulic excavator described above. [Figure 8] Figure 7 is a block diagram showing the configuration of a hydraulic excavator with the above-mentioned piping arranged, along with the flow direction of the heat exchange medium during cooling of the battery unit. [Figure 9] This is a block diagram showing the configuration of the hydraulic excavator described above, along with the flow direction of the heat exchange medium when the battery unit is heated. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings.

[0011] [1. Hydraulic Excavator Configuration] Figure 1 is a side view showing the schematic configuration of an electric hydraulic excavator 1, which is an example of a work machine of this embodiment. The hydraulic excavator 1 comprises a lower traveling body 2, a work machine 3, and an upper rotating body 4. In this embodiment, the hydraulic excavator 1 or the upper rotating body 4 (particularly the engine room 44) is also referred to as the "machine body".

[0012] For the sake of convenience in the following explanation, directions are defined as follows: The direction in which the operator (driver, operator) seated in the driver's seat 41a of the upper slewing body 4 faces forward is defined as the front, and the opposite direction is defined as the rear. Therefore, when the upper slewing body 4 is not slewing relative to the lower traveling body 2 (slewing angle 0°), the longitudinal direction of the upper slewing body 4 coincides with the direction in which the lower traveling body 2 moves forward and backward. Also, the left side as seen from the perspective of the operator seated in the driver's seat 41a is defined as "left," and the right side as "right." Furthermore, the direction of gravity perpendicular to the longitudinal and lateral directions is defined as the up and down direction, with the upstream side of the direction of gravity being defined as "up" and the downstream side as "down." In the drawings, the hydraulic excavator 1 is shown with the upper slewing body 4 not slewing relative to the lower traveling body 2. Also, in the drawings, the forward direction is indicated by the symbol "F," the rear by "B," the right by "R," the left by "L," the upper by "U," and the lower by "D," as needed.

[0013] The lower travel body 2 comprises a pair of left and right crawlers 21 and a pair of left and right travel motors 22. Each travel motor 22 is a hydraulic motor. The left and right travel motors 22 drive the left and right crawlers 21 respectively, allowing the hydraulic excavator 1 to move forward and backward. The lower travel body 2 is equipped with a blade 23 for leveling work and a blade cylinder 23a. The blade cylinder 23a is a hydraulic cylinder that rotates the blade 23 in the vertical direction.

[0014] The working machine 3 includes a boom 31, an arm 32, and a bucket 33. By independently driving the boom 31, the arm 32, and the bucket 33, excavation work such as earth and sand can be performed.

[0015] The boom 31 is rotated by a boom cylinder 31a. The base end of the boom cylinder 31a is supported at the front part of the upper revolving body 4 and is movably extendable and retractable. The arm 32 is rotated by an arm cylinder 32a. The base end of the arm cylinder 32a is supported by the boom 31 and is movably extendable and retractable. The bucket 33 is rotated by a bucket cylinder 33a. The base end of the bucket cylinder 33a is supported by the arm 32 and is movably extendable and retractable. The boom cylinder 31a, the arm cylinder 32a, and the bucket cylinder 33a are constituted by hydraulic cylinders.

[0016] The upper revolving body 4 is located above the lower traveling body 2 and is provided so as to be rotatable with respect to the lower traveling body 2 via a slewing bearing (not shown). A cab 41, a slewing frame 42, a slewing motor 43, an engine room 44, etc. are arranged on the upper revolving body 4. The upper revolving body 4 rotates via the slewing bearing by the drive of the slewing motor 43 which is a hydraulic motor.

[0017] A hydraulic pump 71 (see FIG. 2) is arranged on the upper revolving body 4. The hydraulic pump 71 is driven by an electric motor 61 (see FIG. 2) inside the engine room 44. The hydraulic pump 71 supplies hydraulic oil (pressure oil) to hydraulic motors (for example, left and right traveling motors 22, slewing motor 43) and hydraulic cylinders (for example, blade cylinder 23a, boom cylinder 31a, arm cylinder 32a, bucket cylinder 33a). The hydraulic motors and hydraulic cylinders driven by the supply of hydraulic oil from the hydraulic pump 71 are collectively called a hydraulic actuator 73 (see FIG. 2).

[0018] The operator's cab 41 is arranged in the control unit 41. Various levers 41b are arranged around the operator's cab 41a. When the operator sits on the operator's cab 41a and operates the lever 41b, the hydraulic actuator 73 is driven. As a result, the lower traveling body 2 can travel, the soil leveling work can be performed by the blade 23, the excavation work can be performed by the work implement 3, the upper swing body 4 can swing, and so on.

[0019] A battery unit 53 is arranged in the upper swing body 4. The battery unit 53 is composed of, for example, a lithium-ion battery unit and stores electric power for driving the electric motor 61. The battery unit 53 may be composed of a plurality of batteries unitized, or may be composed of a single battery cell. Further, a power supply port (not shown) is provided in the upper swing body 4. The above power supply port and the commercial power supply 51 which is an external power source are connected via a power supply cable 52. Thereby, the battery unit 53 can be charged.

[0020] A lead battery 54 is further provided in the upper swing body 4. The lead battery 54 outputs a DC voltage of a low voltage (for example, 12V). The output from the lead battery 54 is supplied as a control voltage to, for example, the drive unit of the system controller 67 (see FIG. 2), the fan 81 (see FIG. 3, etc.).

[0021] The hydraulic excavator 1 may have a configuration in which hydraulic devices such as the hydraulic actuator 73 and an actuator driven by electric power are used in combination. Examples of the actuator driven by electric power include an electric traveling motor, an electric cylinder, and an electric swing motor.

[0022] 〔2. Configuration of Electrical System and Hydraulic System〕 Figure 2 is a schematic block diagram showing the electrical and hydraulic system configuration of the hydraulic excavator 1. The hydraulic excavator 1 comprises an electric motor 61, a charger 62, an inverter 63, a PDU (Power Drive Unit) 64, a junction box 65, a DC-DC converter 66, and a system controller 67. The system controller 67 is an electronic control unit also called an ECU (Electronic Control Unit) and performs electrical control of each part of the hydraulic excavator 1.

[0023] The electric motor 61 is driven by power supplied from the battery unit 53 via the junction box 65 and inverter 63. The electric motor 61 consists of a permanent magnet motor or an induction motor. The electric motor 61 is mounted on the slewing frame 42 (see Figure 1).

[0024] The charger 62 (also called a power supply) converts the AC voltage supplied from the commercial power supply 51 shown in Figure 1 via the power supply cable 52 into a DC voltage. The inverter 63 converts the DC voltage supplied from the battery unit 53 into an AC voltage and supplies it to the electric motor 61. This causes the electric motor 61 to rotate. The supply of AC voltage (current) from the inverter 63 to the electric motor 61 is performed based on a rotation command output from the system controller 67.

[0025] The PDU64 is a battery control unit that controls the input and output of the battery unit 53 by controlling an internal battery relay. The junction box 65 is composed of a charger relay, an inverter relay, a fuse, etc. The voltage output from the charger 62 is supplied to the battery unit 53 via the junction box 65 and the PDU64. The voltage output from the battery unit 53 is supplied to the inverter 63 via the PDU64 and the junction box 65.

[0026] The DC-DC converter 66 steps down the high-voltage (e.g., 300V) DC voltage supplied from the battery unit 53 via the junction box 65 to a low voltage (e.g., 12V). The voltage output from the DC-DC converter 66 is supplied to the system controller 67, the fan 81 drive unit, and the like, similar to the output from the lead-acid battery 54.

[0027] Multiple hydraulic pumps 71 are connected to the rotating shaft (output shaft) of the electric motor 61. The multiple hydraulic pumps 71 include variable displacement pumps and fixed displacement pumps. In Figure 2, only one hydraulic pump 71 is shown as an example. Each hydraulic pump 71 is connected to a hydraulic fluid tank 74 that contains (stores) hydraulic fluid. When the electric motor 61 drives the hydraulic pumps 71, the hydraulic fluid in the hydraulic fluid tank 74 is supplied to the hydraulic actuator 73 via a control valve 72. This drives the hydraulic actuator 73. The control valve 72 is a directional control valve that controls the flow direction and flow rate of the hydraulic fluid supplied to the hydraulic actuator 73.

[0028] [3. Internal layout of the engine room] Figure 3 is a perspective view showing the internal configuration of the engine room 44 of the hydraulic excavator 1. The hydraulic excavator 1 is equipped with a fan 81. The fan 81 draws outside air into the machine body by rotation. That is, the fan 81 in this embodiment is a suction type. The rotation axis of the fan 81 extends in the left-right direction of the machine body. Below the fan 81 is a hydraulic pump 71. The hydraulic pump 71 is connected to a hydraulic oil tank 74 (see Figure 2) via a hydraulic hose (not shown).

[0029] The hydraulic excavator 1 is equipped with a radiator 82. The radiator 82 is a heat exchanger that cools a heat exchange medium by heat exchange. The heat exchange medium is, for example, cooling water, but may also be a refrigerant other than cooling water. The radiator 82 is located on the right side of the machine relative to the fan 81.

[0030] An oil cooler 83 is positioned on the left side of the machine relative to the fan 81, that is, on the opposite side of the fan 81 from the radiator 82. The oil cooler 83 is connected to an oil passage through which oil circulates via a hydraulic pump 71 and a hydraulic actuator 73 (see Figure 2), etc. The oil cooler 83 cools the hydraulic fluid flowing through the oil passage by heat exchange when driven by the hydraulic pump 71. The oil cooler 83 is positioned so as to overlap a portion of the fan 81 when viewed from the direction of the fan 81's rotation axis.

[0031] An air duct 84 is positioned on the left side of the machine relative to the oil cooler 83, that is, on the opposite side of the machine from the fan 81 relative to the oil cooler 83. The electric motor 61 is positioned below the air duct 84. A hydraulic pump 71 is positioned on the right side of the machine relative to the electric motor 61.

[0032] As described above, the fan 81 is a suction type, so when the fan 81 is rotated, outside air is drawn in from the outside of the aircraft towards the inside of the aircraft, flows through the inside of the air duct 84, and is discharged to the outside of the aircraft. The radiator 82 and oil cooler 83 are located in the middle of the airflow path, so the radiator 82 and oil cooler 83 are sequentially cooled by the drawn-in outside air. In addition, since the electric motor 61 is located below the air duct 84, the electric motor 61 is cooled by the air discharged from the air duct 84. Furthermore, as shown in Figure 3, the charger 62 and DC-DC converter 66 are located on the side wall of the air duct 84, so the charger 62 and DC-DC converter 66 are also cooled by the air flowing inside the air duct 84.

[0033] The arrangement of the fan 81, radiator 82, and oil cooler 83 described above is merely an example and is not limited to the arrangement of this embodiment. Therefore, by devising an arrangement of the fan 81, radiator 82, and oil cooler 83, it is also possible to configure the fan 81 as a discharge type to cool the radiator 82 and oil cooler 83.

[0034] [4. Positional relationship between the heat exchanger and the battery unit, and piping arrangement] Figure 4 is a perspective view of the main part of the engine room 44 shown in Figure 3, viewed from the right rear. Figure 5 is a perspective view of the main part, viewed from the left rear. Figure 6 is a plan view of the main part. Here, the main part refers to the piping 90 through which the heat exchange medium flows and the members to which the piping 90 is connected.

[0035] As shown in Figures 4 to 6, the hydraulic excavator 1 is equipped with a plurality of the battery units 53 described above. In this embodiment, the hydraulic excavator 1 is equipped with four battery units 53, but the number of battery units 53 is not particularly limited. As shown in Figure 6, the four battery units 53 are vibration-damped and supported on the slewing frame 42 so that their longitudinal direction in a plan view is in the left-right direction of the machine, and are arranged in a line in the front-rear direction of the machine. Each battery unit 53 and the radiator 82 are connected by piping 90. That is, the hydraulic excavator 1 is equipped with piping 90 connected to the battery units 53 through which a heat exchange medium flows, and a radiator 82 as a heat exchanger to which the piping 90 is connected. The piping 90 is formed of, for example, a resin hose, but may be composed of at least a part of a metal pipe or fitting. The detailed configuration of the piping 90 will be described later.

[0036] As shown in Figure 5, the battery unit 53 has a connection port 530 on its left side 53L. The piping 90 is connected to the connection port 530. In other words, the battery unit 53 has a connection port 530 to which the piping 90 is connected on one side, the left side 53L.

[0037] As shown in Figures 5 and 6, the radiator 82 is positioned on the opposite side (e.g., the right side of the aircraft) from the side of the battery unit 53 where it connects to the piping 90 (e.g., the left side of the aircraft). This positional relationship between the radiator 82 and the battery unit 53 allows maintenance on the battery unit 53 to be performed from the side opposite to where the radiator 82 is located (the left side of the aircraft). For example, maintenance on the battery unit 53 can be performed by removing the left-side bonnet (not shown), which forms the side wall of the engine room 44. In this case, the maintenance can be performed without being obstructed by the radiator 82, making the maintenance easier. The maintenance includes connecting and disconnecting the piping 90 to the battery unit 53, and inspecting and checking the connection between the battery unit 53 and the piping 90.

[0038] In particular, to facilitate maintenance around the connection port 530 to the battery unit 53, it is desirable to allow maintenance of the battery unit 53 from the left side 53L where the connection port 530 is located. In this regard, as shown in Figure 5, etc., it is desirable that the radiator 82 be positioned on the side opposite to the aforementioned side (left side 53L) (right side 53R) relative to the battery unit 53 (see Figures 4 and 6 in particular).

[0039] As shown in Figure 5, the connection port 530 of the battery unit 53 includes a first connection port 531 and a second connection port 532. Both the first connection port 531 and the second connection port 532 are provided on the left side surface 53L of the battery unit 53. On the left side surface 53L, the first connection port 531 and the second connection port 532 are arranged side by side in the vertical direction. Specifically, the second connection port 532 is located above the first connection port 531.

[0040] From the standpoint of enabling maintenance of the first connection port 531 and the second connection port 532 to be performed together, it is desirable that the multiple connection ports 530, including the first connection port 531 and the second connection port 532, be provided on the same side of the battery unit 53 (the left side 53L in the above example).

[0041] The first connection port 531 and the second connection port 532 are connected to one end and the other end of a circuit that circulates the heat exchange medium within the battery unit 53, respectively. In this case, as described above, the first connection port 531 and the second connection port 532 are located on the same side (left side 53L) of each battery unit 53, allowing the heat exchange medium to flow into each battery unit 53 from the same side and discharge from each battery unit 53 to the same side. This makes the connection configuration to the piping 90 for each battery unit 53 compact, using short piping (for example, multiple first individual piping 91c and multiple second individual piping 92c described later). Therefore, in order to realize a circuit that cools multiple battery units 53 with a simple piping 90 arrangement, it is desirable, as in this embodiment, that the first connection port 531 and the second connection port 532 are connected to one end and the other end of a circuit that circulates the heat exchange medium within the battery unit 53, respectively.

[0042] The number of battery units 53 may be one. Even in this case, by positioning the first connection port 531, which is the inlet side of the heat exchange medium, and the second connection port 532, which is the outlet side, on one side of the battery unit 53 (for example, the left side 53L), it is possible to realize a circuit for cooling the battery unit 53 with a simple wiring of piping 90.

[0043] Furthermore, as shown in Figures 5 and 6, when multiple battery units 53 are arranged side by side on the rotating frame 42, it is desirable that maintenance on each battery unit 53 be performed collectively from the same side (for example, the left side of the aircraft) so that maintenance on each battery unit 53 can be performed efficiently. From this viewpoint, it is desirable that the piping 90 be connected to each of the multiple battery units 53 on the same side. In other words, it is desirable that the multiple battery units 53 be arranged such that one side of each of them (for example, the left side 53L) (where the connection port 530 to the piping 90 is provided) faces the same direction (to the left of the aircraft in Figures 5 and 6).

[0044] Next, the details of the piping 90 described above will be explained. As shown in Figures 4 to 6, the piping 90 has a first common pipe 91a extending from the radiator 82 and first individual pipes 91c connected to the first common pipe 91a via a branch section 91b. Multiple first individual pipes 91c are provided corresponding to each battery unit 53, and each extends from the first connection port 531 of the multiple battery units 53. A circulation pump 93 and a heater 94, which will be described later, are arranged in the middle of the first common pipe 91a.

[0045] Furthermore, the piping 90 includes a second common pipe 92a extending from the radiator 82 and a second individual pipe 92c connected to the second common pipe 92a via a junction 92b. Multiple second individual pipes 92c are provided corresponding to each battery unit 53, and each extends from a second connection port 532 of the multiple battery units 53.

[0046] In the piping configuration 90 described above, the heat exchange medium discharged from the radiator 82 flows through the first common pipe 91a, is evenly distributed to the four first individual pipes 91c at the branching section 91b, and flows from each first individual pipe 91c through the first connection port 531 into the corresponding battery unit 53, cooling the battery unit 53. The heat exchange medium that has flowed inside the battery unit 53 flows from the second connection port 532 through the second individual pipe 92c to the junction section 92b, where it merges with the heat exchange medium that has flowed in from the other battery unit 53 through the corresponding second individual pipe 92c, and then flows through the second common pipe 92a back to the radiator 82. Thereafter, this circulation of the heat exchange medium is repeated.

[0047] From the standpoint of making the layout of the piping 90 compact, it is desirable to have a configuration like that of this embodiment, in which a plurality of first individual pipes 91c connected to each battery unit 53 are connected to a single first common pipe 91a via a branching section 91b, and a plurality of second individual pipes 92c connected to each battery unit 53 are connected to a single second common pipe 92a via a merging section 92b.

[0048] Furthermore, in order to efficiently regulate the temperature of the battery unit 53 using the heat exchange medium (for example, cooling), it is desirable to fill the inside of the battery unit 53 with the heat exchange medium. To achieve this, it is desirable to allow the air inside the battery unit 53 to escape to the outside. In order to allow the air inside the battery unit 53 to escape upward and prevent air from accumulating inside the battery unit 53, it is desirable that the second common pipe 92a be located above the battery unit 53, as shown in Figures 4 and 5.

[0049] From the perspective of effectively utilizing the space around the battery unit 53 as routing space for the first common piping 91a, branch section 91b, and first individual piping 91c, it is desirable that the first common piping 91a be routed through the rear side of each battery unit 53, as shown in Figure 6. In other words, it is desirable that the first common piping 91a be routed outside the battery unit 53 (offset from the battery unit 53) when viewed from above.

[0050] As shown in Figures 4 and 6, a circulation pump 93 is positioned in the middle of the piping 90 (particularly the first common piping 91a). The circulation pump 93 draws in the heat exchange medium after it has been cooled by the radiator 82 and pushes it towards the battery unit 53. The circulation pump 93 is positioned below the radiator 82 and on the right side of the aircraft relative to the battery unit 53. The circulation pump 93 is positioned on the rear side of the aircraft relative to the radiator 82, but it may also be positioned on the front side of the aircraft relative to the radiator 82.

[0051] The heat exchange medium, after flowing through the battery unit 53, absorbs heat from the battery unit 53 and its temperature rises. If the high-temperature heat exchange medium is supplied directly to the circulation pump 93, the circulation pump 93 may be damaged. From the viewpoint of protecting the circulation pump 93 and avoiding damage to the circulation pump 93 due to the supply of high-temperature heat exchange medium, it is desirable to supply the heat exchange medium to the circulation pump 93 after it has been cooled by the radiator 82. In this respect, it is desirable to position the circulation pump 93 in the middle of the first common piping 91a through which the heat exchange medium flows from the radiator 82 to the battery unit 53, as shown in Figure 4, etc. In other words, it is desirable to position the circulation pump 93 downstream of the radiator 82 in the direction in which the heat exchange medium flows.

[0052] In this embodiment, as shown in Figure 4, a heater 94 is further arranged in the middle of the piping 90. In particular, the heater 94 is arranged downstream of the circulation pump 93 in the first common piping 91a in the direction in which the heat exchange medium flows. The heater 94 is arranged on the front side of the machine relative to the radiator 82, but it may also be arranged on the rear side of the machine.

[0053] With the heater 94 turned off (not energized), the fan 81 (see Figure 3) is driven to blow outside air onto the radiator 82, thereby cooling the heat exchange medium flowing through the radiator 82 through heat exchange. In this case, the relatively low-temperature heat exchange medium can be supplied to the battery unit 53 by the circulation pump 93, thereby cooling the battery unit 53. On the other hand, with the fan 81 stopped, the heater 94 is energized and turned on, so that the heat exchange medium supplied by the circulation pump 93 is heated by the heater 94 and supplied to the battery unit 53, thereby warming the battery unit 53. Therefore, from the viewpoint of enabling the battery unit 53 to be used within an appropriate temperature range in cold weather, it is desirable to place the heater 94 in the middle of the piping 90, as in this embodiment.

[0054] [5. Other examples of piping arrangements] Figure 7 is a perspective view showing another example of the piping 90 configuration in the hydraulic excavator 1. Figures 8 and 9 are schematic block diagrams showing the configuration of the hydraulic excavator 1 with the piping 90 configured as shown in Figure 7. Figure 8 also shows the flow direction of the heat exchange medium when the battery unit 53 is being cooled. Figure 9 also shows the flow direction of the heat exchange medium when the battery unit 53 is being heated.

[0055] As shown in Figure 7, the arrangement of multiple (e.g., four) battery units 53 mounted on the hydraulic excavator 1 in the front-to-rear direction of the machine is the same as in the configuration shown in Figure 4, etc. Also, the arrangement of multiple connection ports 530 (first connection port 531, second connection port 532) on the left side 53L of each battery unit 53 is the same as in the configuration shown in Figure 4, etc. Therefore, in the configuration shown in Figure 7, the multiple battery units 53 are arranged such that one side of each (e.g., the left side 53L) (where the multiple connection ports 530 are provided) faces the same direction (e.g., to the left of the machine).

[0056] For the sake of convenience in the following explanation, the four battery units 53 arranged in the front-to-rear direction of the machine will also be referred to as the first battery unit 53-1, the second battery unit 53-2, the third battery unit 53-3, and the fourth battery unit 53-4, in order from the front to the rear of the machine. The first battery unit 53-1 and the second battery unit 53-2 constitute the first battery group 53G1. The third battery unit 53-3 and the fourth battery unit 53-4 constitute the second battery group 53G2. In other words, the hydraulic excavator 1 is equipped with a first battery group 53G1 having multiple battery units 53 and a second battery group 53G2 having multiple battery units 53. Each battery unit 53 is connected to a pipe 90 through which a heat exchange medium flows.

[0057] As shown in Figures 7 to 9, the piping 90 includes a first pipe 101, a second pipe 102, a third pipe 103, and a fourth pipe 104.

[0058] The first piping 101 has a first connecting piping 101a extending from the temperature control circuit 200 (see Figures 8 and 9), and a second connecting piping 101c connected to the first connecting piping 101a via a first connection part 101b. The second connecting piping 101c is provided corresponding to the second battery unit 53-2 and the third battery unit 53-3, and extends from the first connection port 531 of the second battery unit 53-2 and the first connection port 531 of the third battery unit 53-3, respectively. In other words, the first piping 101 connects one of the battery units 53 included in the first battery group 53G1 (here, the second battery unit 53-2) and one of the battery units 53 included in the second battery group 53G2 (here, the third battery unit 53-3) to the temperature control circuit 200.

[0059] The temperature control circuit 200 described above adjusts the temperature of the heat exchange medium flowing through the piping 90. In other words, the hydraulic excavator 1 is equipped with a temperature control circuit 200. Details of the temperature control circuit 200 will be described later.

[0060] The second pipe 102 connects the first connection port 531 of the first battery unit 53-1 to the second connection port 532 of the second battery unit 53-2. In other words, the second pipe 102 connects multiple battery units 53 included in the first battery group 53G1 (in this case, the first battery unit 53-1 and the second battery unit 53-2) in series.

[0061] The third pipe 103 connects the second connection port 532 of the third battery unit 53-3 to the first connection port 531 of the fourth battery unit 53-4. In other words, the third pipe 103 connects multiple battery units 53 included in the second battery group 53G2 (in this case, the third battery unit 53-3 and the fourth battery unit 53-4) in series.

[0062] The fourth piping 104 has a third connecting piping 104a extending from the temperature control circuit 200, and a fourth connecting piping 104c connected to the third connecting piping 104a via a second connecting part 104b. The fourth connecting piping 104c is provided corresponding to the first battery unit 53-1 and the fourth battery unit 53-4, and extends from the second connection port 532 of the first battery unit 53-1 and the second connection port 532 of the fourth battery unit 53-4, respectively. In other words, the fourth piping 104 connects the temperature control circuit 200 to the other battery units 53 included in the first battery group 53G1 (here, the first battery unit 53-1) and the other battery units 53 included in the second battery group 53G2 (here, the fourth battery unit 53-4).

[0063] As the piping 90 is configured as described above, when the heat exchange medium is supplied from the temperature control circuit 200 to the first piping 101, the heat exchange medium is divided into a first route and a second route and led to the fourth piping 104, and then returns to the temperature control circuit 200. Here, the first route is the route through which the heat exchange medium flows from the first piping 101 to the fourth piping 104, passing through the second battery unit 53-2, the second piping 102, and the first battery unit 53-1. The second route is the route through which the heat exchange medium flows from the first piping 101 to the fourth piping 104, passing through the third battery unit 53-3, the third piping 103, and the fourth battery unit 53-4.

[0064] Regardless of whether the heat exchange medium flows through the first or second route, the heat exchange medium flows through the battery units 53 located on the inside of the aircraft in the longitudinal direction (second battery unit 53-2, third battery unit 53-3) before the battery units 53 located on the outside of the aircraft in the longitudinal direction (first battery unit 53-1, fourth battery unit 53-4). Therefore, the temperature of the battery units 53 located on the inside of the aircraft in the longitudinal direction can be prioritized for temperature control (e.g., cooling).

[0065] On the other hand, when the heat exchange medium is supplied from the temperature control circuit 200 to the fourth pipe 104, the heat exchange medium is divided into a third route and a fourth route and led to the first pipe 101, and then returned to the temperature control circuit 200. Here, the third route is the route through which the heat exchange medium flows from the fourth pipe 104 to the first pipe 101, passing through the first battery unit 53-1, the second pipe 102, and the second battery unit 53-2. The fourth route is the route through which the heat exchange medium flows from the fourth pipe 104 to the first pipe 101, passing through the fourth battery unit 53-4, the third pipe 103, and the third battery unit 53-3.

[0066] Regardless of whether the heat exchange medium flows through the third or fourth route, the heat exchange medium flows through the battery units 53 located on the outside of the aircraft in the longitudinal direction (first battery unit 53-1, fourth battery unit 53-4) before the battery units 53 located on the inside of the aircraft in the longitudinal direction (second battery unit 53-2, third battery unit 53-3). Therefore, the temperature of the battery units 53 located on the outside of the aircraft in the longitudinal direction can be prioritized for temperature control (e.g., heating).

[0067] Thus, the configuration of the piping 90 shown in Figure 7 is desirable because it allows for prioritizing the temperature control of some of the battery units 53 over those of the other battery units 53.

[0068] Furthermore, in the piping arrangement 90 shown in Figure 7, adjacent battery units 53 included in the first battery group 53G1 (first battery unit 53-1 and second battery unit 53-2) can be connected by a short second pipe 102. Similarly, adjacent battery units 53 included in the second battery group 53G2 (third battery unit 53-3 and fourth battery unit 53-4) can be connected by a short third pipe 103. This makes the layout of the piping 90 more compact, and in this respect as well, the piping arrangement 90 shown in Figure 7 is desirable.

[0069] Next, the details of the temperature control circuit 200 described above will be explained. As shown in Figures 8 and 9, the temperature control circuit 200 is configured with a switching valve 95 in addition to the radiator 82, circulation pump 93, and heater 94 described above. The switching valve 95 switches the destination of the heat exchange medium from the radiator 82 or heater 94 between the first pipe 101 and the fourth pipe 104. Such a switching valve 95 is configured as, for example, a solenoid valve, but it may also be configured as a valve that switches the destination of the heat exchange medium by manual operation. In the temperature control circuit 200, the radiator 82 and heater 94 are arranged in parallel. Within the temperature control circuit 200, the heat exchange medium flows through the radiator 82 or heater 94 via the circulation pump 93 and is supplied to the switching valve 95.

[0070] Here, among the multiple battery units 53 included in the first battery group 53G1, the second battery unit 53-2 to which the first pipe 101 is connected, and among the multiple battery units 53 included in the second battery group 53G2, the third battery unit 53-3 to which the first pipe 101 is connected, are each designated as first pipe-connected battery units 53P. Also, among the multiple battery units 53 included in the first battery group 53G1, the other first battery unit 53-1 to which the fourth pipe 104 is connected, and among the multiple battery units 53 included in the second battery group 53G2, the other fourth battery unit 53-4 to which the fourth pipe 104 is connected, are each designated as fourth pipe-connected battery units 53Q. As shown in Figure 7, in the longitudinal direction of the aircraft, the two first pipe-connected battery units 53P are positioned between the two fourth pipe-connected battery units 53Q.

[0071] When multiple battery units 53 are arranged in a line in the front-to-back direction of the aircraft, if each battery unit 53 generates heat during use, heat dissipation is more efficient for battery units 53 located near both ends of the arrangement direction (for example, the first battery unit 53-1 and the fourth battery unit 53-4). In contrast, heat dissipation is less efficient for battery units 53 located near the center of the arrangement direction (for example, the second battery unit 53-2 and the third battery unit 53-3), and heat tends to accumulate.

[0072] As described above, the two first piping-connected battery units 53P are positioned between the two fourth piping-connected battery units 53Q. This allows the (low-temperature) heat exchange medium, immediately after being cooled by the radiator 82 included in the temperature control circuit 200, to be supplied to the first piping-connected battery units 53P via the first piping 101 before the fourth piping-connected battery units 53Q, thereby prioritizing the cooling of the first piping-connected battery units 53P, which tend to accumulate heat.

[0073] On the other hand, in cold weather, battery units 53 located near both ends of the array direction (for example, the first battery unit 53-1 and the fourth battery unit 53-4) lose heat more easily and their temperature drops more quickly than battery units 53 located near the center of the array direction (for example, the second battery unit 53-2 and the third battery unit 53-3).

[0074] The two fourth-pipe connected battery units 53Q are located outward in the alignment direction relative to the two first-pipe connected battery units 53P. Therefore, the heat exchange medium heated by the heater 94 can be supplied to the fourth-pipe connected battery units 53Q via the fourth pipe 104 before the first-pipe connected battery units 53P, thereby prioritizing the heating of the fourth-pipe connected battery units 53Q, which tend to lose temperature easily in cold weather.

[0075] Thus, considering the differences in heat dissipation depending on the placement of the multiple battery units 53, and switching which battery unit 53 receives the heat exchange medium preferentially, it is desirable to place the two first piping-connected battery units 53P between the two fourth piping-connected battery units 53Q in order to achieve a uniform temperature across all the multiple battery units 53 and to ensure uniform degradation of the battery units 53.

[0076] In particular, from the viewpoint of enabling priority cooling of the first piping-connected battery unit 53P, which tends to accumulate heat, over the fourth piping-connected battery unit 53Q, it is desirable that the switching valve 95 switches the supply destination of the heat exchange medium cooled by the radiator 82 to the first piping 101 when cooling each battery unit 53 included in the first battery group 53G1 and the second battery group 53G2.

[0077] Furthermore, from the viewpoint of supplying a high-temperature heat exchange medium to the fourth pipe-connected battery unit 53Q before the first pipe-connected battery unit 53P, thereby prioritizing the heating of the fourth pipe-connected battery unit 53Q, it is desirable that the switching valve 95 switches the supply destination of the heat exchange medium heated by the heater 94 to the fourth pipe 104 when each battery unit 53 is heated.

[0078] In the above explanation, a hydraulic excavator 1, a construction machine, was used as an example of a working machine. However, the working machine is not limited to a hydraulic excavator 1; it may be other construction machines such as a wheel loader. Furthermore, the working machine may be agricultural machinery such as a combine harvester or tractor.

[0079] [6. Addendum] The hydraulic excavator 1 described in this embodiment can also be described as the work machine shown in the following appendix.

[0080] The work machines mentioned in Appendix (1) are: Battery unit and A piping connected to the aforementioned battery unit through which a heat exchange medium flows, The heat exchanger to which the aforementioned piping is connected comprises, The heat exchanger is positioned on the side of the battery unit opposite to the side of the battery unit that is connected to the piping.

[0081] The work machines in Appendix (2) are the work machines described in Appendix (1), The battery unit has a connection port on one side to which the piping is connected, The heat exchanger is positioned on the side opposite to the one side of the battery unit.

[0082] The work machines in Appendix (3) are the work machines described in Appendix (2), The aforementioned connection port includes a first connection port and a second connection port, The first connection port and the second connection port are connected to one end and the other end of a circuit that circulates the heat exchange medium within the battery unit, respectively.

[0083] The work machines in Appendix (4) are the work machines described in Appendix (3), The battery unit comprises multiple such units, Multiple battery units are arranged such that each of their respective sides faces the same direction.

[0084] The work machines in Appendix (5) are the work machines described in Appendix (4), The aforementioned piping is The heat exchanger The first common piping extends from, The first common piping is connected via a branch section, and the first individual piping extends from the first connection port of each of the multiple battery units, The heat exchanger The second common pipe extending from there, It has a second individual pipe that is connected to the second common pipe via a junction and extends from the second connection port of each of the multiple battery units.

[0085] The work machines in Appendix (6) are the work machines described in Appendix (5), The second connection port is located above the first connection port. The second common piping is positioned above the battery unit.

[0086] The work machines in Appendix (7) are the work machines described in Appendix (5) or (6), The first common piping is routed to pass outside the battery unit when viewed from above.

[0087] The work machine in Appendix (8) is the work machine described in any of Appendix (1) to (7), The piping is further equipped with a circulation pump located in the middle of the aforementioned piping. The circulation pump is positioned downstream of the heat exchanger in the direction in which the heat exchange medium flows.

[0088] The work machine in Appendix (9) is the work machine described in any of Appendix (1) to (8), The system further includes a heater positioned in the middle of the aforementioned piping.

[0089] The work machine in Appendix (10) is the work machine described in Appendix (2) or (3), A first battery group having multiple of the aforementioned battery units, A second battery group having multiple of the aforementioned battery units, The system includes a temperature control circuit for adjusting the temperature of the heat exchange medium, All of the battery units in the first battery group and the second battery group are arranged such that one side of each of them faces the same direction. The aforementioned piping is A first pipe connecting any battery unit included in the first battery group and any battery unit included in the second battery group to the temperature control circuit, A second pipe connects multiple battery units included in the first battery group in series, A third pipe connects multiple battery units included in the second battery group in series, The system includes a fourth pipe connecting the other battery units included in the first battery group and the other battery units included in the second battery group to the temperature control circuit.

[0090] The work machine in Appendix (11) is the work machine described in Appendix (10), The temperature control circuit includes the heat exchanger and the heater, Among the multiple battery units included in the first battery group, the battery unit to which the first piping is connected, and among the multiple battery units included in the second battery group, the battery unit to which the first piping is connected, are each designated as the first piping-connected battery unit. When the battery units included in the first battery group to which the fourth pipe is connected, and the battery units included in the second battery group to which the fourth pipe is connected, are each designated as fourth pipe-connected battery units, The two first piping connection battery units are positioned between the two fourth piping connection battery units.

[0091] The work machine in Appendix (12) is the work machine described in Appendix (11), The temperature control circuit further includes a switching valve that switches the supply destination of the heat exchange medium from the heat exchanger or the heater between the first pipe and the fourth pipe, The switching valve switches the supply destination of the heat exchange medium cooled by the heat exchanger to the first piping when cooling each battery unit included in the first battery group and the second battery group.

[0092] The work machine in Appendix (13) is the work machine described in Appendix (12), When each of the battery units is heated, the switching valve switches the supply destination of the heat exchange medium heated by the heater to the fourth pipe.

[0093] Although embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and it can be expanded or modified without departing from the spirit of the invention. [Industrial applicability]

[0094] This invention can be used, for example, in work machinery such as construction machinery and agricultural machinery. [Explanation of symbols]

[0095] 1. Hydraulic excavator (working machine) 53 Battery Unit 53-1 First Battery Unit 53-2 Second Battery Unit 53-3 Third Battery Unit 53-4 Fourth Battery Unit 53G1 Battery Group 1 53G2 Second Battery Group 53L left side (one side) 53P First Piping Connection Battery Unit 53Q 4th Piping Connection Battery Unit 53R Right side (opposite side) 82. Radiator (heat exchanger) 90 Piping 91a First common piping 91b Branch 91c First Individual Piping 92a Second common piping 92b Confluence 92c Second Individual Piping 93 Circulation pump 94 Heater 95 Switching valve 101 First Piping 101a First connecting pipe 101b First connection section 101c Second connecting pipe 102 Second Piping 103 Third Piping 104 Fourth pipe 104a Third connecting pipe 104b Second connection section 104c Fourth connecting pipe 200 Temperature control circuit 530 connection ports 531 First connection port 532 Second connection port

Claims

1. Battery unit and A piping connected to the aforementioned battery unit through which a heat exchange medium flows, The heat exchanger to which the aforementioned piping is connected comprises, The heat exchanger is positioned on the side of the battery unit opposite to the side of the battery unit that is connected to the piping, in this work machine.

2. The battery unit has a connection port on one side to which the piping is connected, The work machine according to claim 1, wherein the heat exchanger is positioned on the side opposite to the one side of the battery unit.

3. The aforementioned connection port includes a first connection port and a second connection port. The work machine according to claim 2, wherein the first connection port and the second connection port are connected to one end and the other end of a circuit for circulating the heat exchange medium within the battery unit, respectively.

4. The battery unit comprises multiple such units, The work machine according to claim 3, wherein a plurality of the battery units are arranged such that each of the aforementioned side surfaces faces the same direction.

5. The aforementioned piping is A first common pipe extending from the heat exchanger, The first common piping is connected via a branch section, and the first individual piping extends from the first connection port of each of the multiple battery units, A second common pipe extending from the heat exchanger, The work machine according to claim 4, further comprising: second individual pipes connected to the second common pipe via a junction, and each extending from the second connection port of a plurality of battery units.

6. The second connection port is located above the first connection port. The work machine according to claim 5, wherein the second common piping is positioned above the battery unit.

7. The work machine according to claim 5, wherein the first common piping is routed outside the battery unit when viewed from above.

8. The piping is further equipped with a circulation pump located in the middle of the aforementioned piping. The working machine according to claim 1, wherein the circulation pump is arranged downstream of the heat exchange medium in the direction in which the heat exchange medium flows relative to the heat exchanger.

9. The work machine according to claim 1, further comprising a heater positioned in the middle of the aforementioned piping.

10. A first battery group having multiple of the aforementioned battery units, A second battery group having multiple of the aforementioned battery units, The system includes a temperature control circuit for adjusting the temperature of the heat exchange medium, All of the battery units in the first battery group and the second battery group are arranged so that one side of each of them faces the same direction. The aforementioned piping is A first pipe connecting any battery unit included in the first battery group and any battery unit included in the second battery group to the temperature control circuit, A second pipe connects multiple battery units included in the first battery group in series, A third pipe connects multiple battery units included in the second battery group in series, The work machine according to claim 2, further comprising a fourth pipe connecting the other battery units included in the first battery group and the other battery units included in the second battery group to the temperature control circuit.

11. The temperature control circuit includes the heat exchanger and the heater, Among the multiple battery units included in the first battery group, the battery unit to which the first piping is connected, and among the multiple battery units included in the second battery group, the battery unit to which the first piping is connected, are each designated as the first piping-connected battery unit. When the battery units included in the first battery group to which the fourth pipe is connected, and the battery units included in the second battery group to which the fourth pipe is connected, are each designated as fourth pipe-connected battery units, The work machine according to claim 10, wherein the two first pipe connection battery units are arranged between the two fourth pipe connection battery units.

12. The temperature control circuit further includes a switching valve that switches the destination of the heat exchange medium from the heat exchanger or the heater between the first pipe and the fourth pipe, The working machine according to claim 11, wherein the switching valve switches the supply destination of the heat exchange medium cooled by the heat exchanger to the first piping when cooling each battery unit included in the first battery group and the second battery group.

13. The work machine according to claim 12, wherein the switching valve switches the supply destination of the heat exchange medium heated by the heater to the fourth pipe when each of the battery units is heated.

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