Construction machine

Abstract

To easily increase the capacity of a battery mounted in an electric construction machine, according to a work site or work contents.SOLUTION: A construction machine 1 is an electric construction machine comprising: a battery 20 mounted in a vehicle body; a front work device 5 provided at a front part of the vehicle body and configured to be driven by the battery 20 as a power source; and a counterweight 30 provided at a rear part of the vehicle body. The construction machine 1 includes: an additional counterweight 40 detachably attached to a rear surface of the counterweight 30; and an additional battery 60 configured to supply electric power to the battery 20. The additional battery 60 is provided in the additional counterweight 40.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electric construction machine. [Background technology]

[0002] In recent years, electric construction machinery powered by batteries has been proposed to reduce the burden on the environment. In particular, small hydraulic excavators are often used indoors, so electric construction machinery that does not emit exhaust gases offers significant advantages compared to medium- or large-sized hydraulic excavators.

[0003] Generally, electric construction machinery is required to have a longer continuous operating time. However, due to limitations on the battery capacity that can be installed, if it is difficult to cover the entire day's work hours depending on the type of work, it becomes necessary to charge the battery during non-operating times, such as during breaks. However, charging the battery during every break is time-consuming, and it is often not possible to install charging equipment near the work site. Therefore, there is a demand for larger-capacity batteries installed in construction machinery.

[0004] Patent Document 1 discloses an electric construction machine that has a battery device (31) mounted in the rear portion of a vehicle body (3) and that performs work by driving an electric motor (18) with the battery device. The electric construction machine disclosed in Patent Document 1 has the vehicle body (3) composed of a vehicle body main body (100) and a vehicle body rear portion (200). The vehicle body has a vehicle body frame (101) to which a working device (4) is attached at the front side, and a driver's seat (102) and a machine room (103) provided on the vehicle body frame. The vehicle body frame has a main frame (120) to which a working device is attached at the front side, and the main frame has an overhang (122) that overhangs in the fore-and-aft direction below the vehicle body rear portion. The rear of the vehicle body has a rear frame (201) placed on the overhang, and a rear cover (205) shaped like a counterweight that covers the rear frame and forms a battery compartment (204) in which the battery device (31) is placed. The rear frame, while placed on the overhang, is fixed to the overhang with bolts (302) and can be separated from the overhang by removing the bolts. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2011 / 158686 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in construction machinery, if an attempt is made to increase the size of the battery pack placed inside the battery compartment as in Patent Document 1, it becomes necessary to increase the size of the battery compartment as well, which may impair the operator's visibility or make the vehicle more susceptible to collisions with objects around the vehicle body.

[0007] In view of the above circumstances, an object of the present invention is to easily increase the capacity of a battery mounted on an electric construction machine depending on the work site or the work content. [Means for solving the problem]

[0008] In order to solve the above problems, the construction machine of the present invention is an electric construction machine comprising a battery mounted on a vehicle body, a front working device provided at the front of the vehicle body and driven using the battery as a power source, and a counterweight provided at the rear of the vehicle body, and is characterized in that it also comprises an additional counterweight detachably attached to the rear surface of the counterweight, and an additional battery that supplies power to the battery, the additional battery being provided on the additional counterweight. [Effects of the Invention]

[0009] According to the present invention, it is possible to easily increase the capacity of the battery mounted on an electric construction machine depending on the work site or the work content. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a side view showing a configuration of a construction machine. [Figure 2] FIG. 2 is a block diagram showing the electrical configuration of the construction machine shown in FIG. 1. [Figure 3] FIG. 2 is a diagram showing a counterweight and an additional counterweight of the construction machine shown in FIG. 1. [Figure 4] FIG. 4 is a front view of the counterweight shown in FIG. 3. [Figure 5] FIG. 4 is a front view of the additional counterweight shown in FIG. 3. [Figure 6] 4 is a diagram illustrating the mounting structure of the counterweight and additional counterweight shown in FIG. 3. FIG. [Figure 7] FIG. 4 is a diagram showing details of the internal configuration of the additional counterweight shown in FIG. 3. [Figure 8] FIG. 8 is an enlarged view of the right part of the additional counterweight shown in FIG. 7. [Figure 9] FIG. 8 is a diagram showing the underside of the additional counterweight shown in FIG. 7. [Figure 10]8 is a diagram illustrating an electrical connection structure of the plurality of battery modules shown in FIG. 7. [Figure 11] 8 is a diagram illustrating a mechanical connection structure of the plurality of battery modules shown in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components with the same reference numerals in each embodiment have similar components in each embodiment unless otherwise specified, and description thereof will be omitted.

[0012] In this embodiment, the line of sight of an operator seated in the driver's seat inside the cab 4 is defined as the "forward direction," and the opposite direction is defined as the "rearward direction." A direction toward the right hand side of an operator seated in the driver's seat and perpendicular to the front-to-rear direction is defined as the "rightward direction," and the opposite direction is defined as the "leftward direction." A direction toward the top of the operator seated in the driver's seat and perpendicular to the front-to-rear and left-to-right directions is defined as the "upward direction," and the opposite direction is defined as the "downward direction."

[0013] FIG. 1 is a side view showing the configuration of a construction machine 1. As shown in FIG.

[0014] The construction machine 1 is an electrically powered construction machine powered by electricity from a battery 20 mounted on the vehicle body. The construction machine 1 may be, for example, a hydraulic excavator, a wheel loader, or a crane. In particular, the construction machine 1 may be a small construction machine for which it is difficult to secure sufficient space to accommodate the battery 20. In this embodiment, the construction machine 1 will be described taking as an example a small hydraulic excavator of a small rear swing type or an ultra-small rear swing type.

[0015] The construction machine 1 is composed of a self-propelled lower running body 2, an upper rotating body 3 rotatably mounted on the lower running body 2, and a front working device 5 rotatably mounted to the front of the upper rotating body 3.

[0016] The front working mechanism 5 includes a boom 6 rotatably attached to the upper rotating body 3, an arm 7 rotatably attached to the boom 6, and a bucket 8 rotatably attached to the arm 7. The boom 6, arm 7, and bucket 8 are supported by a boom cylinder 9, an arm cylinder 10, and a bucket cylinder 11, respectively, and are driven by these hydraulic cylinders 9-11.

[0017] The upper rotating body 3 is equipped with a body frame 3a that forms a support structure for the upper rotating body 3. A front working implement 5 for performing excavation work and the like is mounted on the front of the body frame 3a. A cab 4 for an operator is mounted on the left side of the body frame 3a. A battery 20, which is the power source for the construction machine 1, is mounted on the rear of the body frame 3a. A counterweight 30, which balances the weight with the front working implement 5, is mounted on the rear of the body frame 3a, behind the battery 20. An additional counterweight 40 is detachably attached to the rear surface of the counterweight 30. The additional counterweight 40 includes an additional battery 60 that supplies power to the battery 20.

[0018] FIG. 2 is a block diagram showing the electrical configuration of the construction machine 1 shown in FIG.

[0019] The construction machine 1 is equipped with a hydraulic pump that supplies pressure oil to a traveling hydraulic motor that drives the lower traveling structure 2, a swing hydraulic motor that drives the upper swing structure 3, and hydraulic cylinders 9 to 11 that drive the front working mechanism 5. The hydraulic pump is driven by an electric motor 16. The electric motor 16 is, for example, a three-phase AC motor. Driving power for the electric motor 16 is supplied via an inverter 15 that converts DC power from a battery 20 into AC power.

[0020] The battery 20 is mounted on the construction machine 1 in the form of a box-shaped battery pack. This battery pack contains at least a plurality of battery modules 21 and a junction box 22. The battery modules 21 are composed of secondary batteries such as lithium-ion batteries. The junction box 22 is connected to the power path between the plurality of battery modules 21 and the inverter 15. The junction box 22 monitors and manages the transmission and reception of power between the plurality of battery modules 21 and the inverter 15. In addition, the battery modules 21 are connected to a service plug 23 that cuts off the power path between the battery modules 21 to prevent electric shock during maintenance, etc.

[0021] Similar to the battery 20, the additional battery 60 has a plurality of battery modules 61 configured from secondary batteries such as lithium-ion batteries. The additional battery 60 is connected to the junction box 22 of the battery 20. Under the control of the junction box 22, the additional battery 60 supplies power to the battery modules 21 of the battery 20 when the charging power of the battery 20 is insufficient. The additional battery 60 enables the construction machine 1 to have a large capacity battery installed.

[0022] A structure for realizing the mounting of the additional battery 60 on the construction machine 1 will be described with reference to FIGS.

[0023] Fig. 3 is a diagram showing the counterweight 30 and additional counterweight 40 of the construction machine 1 shown in Fig. 1. Fig. 4 is a diagram showing the front of the counterweight 30 shown in Fig. 3. Fig. 5 is a diagram showing the front of the additional counterweight 40 shown in Fig. 3. Fig. 6 is a diagram explaining the mounting structure of the counterweight 30 and additional counterweight 40 shown in Fig. 3.

[0024] As shown in Fig. 3, the counterweight 30 is provided at the rear of the upper rotating body 3, behind the battery 20. As shown in Figs. 4 and 6, the counterweight 30 is provided with insert nuts 32 for attaching the additional counterweight 40 to the counterweight 30. As shown in Figs. 4 and 6, the counterweight 30 is provided with mounting holes 33 for attaching the counterweight 30 to the body frame 3a. As shown in Fig. 6, the counterweight 30 is fixed by inserting multiple sets (e.g., three sets) of bolts 35 and washers 36 into the mounting holes 33 and tightening them against a fixing plate 3b extending upward from the rear of the body frame 3a.

[0025] As shown in Fig. 4, the counterweight 30 is provided with a first connector 31. As shown in Fig. 4 or 6, the first connector 31 has a front insertion port 31a and a rear insertion port 31b.

[0026] A front socket 31a of the first connector 31 is exposed from the front surface of the counterweight 30. A cable 25 extending from the battery 20 is inserted into the front socket 31a of the first connector 31. The cable 25 is a cable for supplying power and is connected to a connector 24 provided on the rear surface of the battery 20.

[0027] A rear insertion port 31b of the first connector 31 is exposed from the rear surface of the counterweight 30. A second connector 41 provided on the additional counterweight 40 is inserted into the rear insertion port 31b of the first connector 31.

[0028] As shown in Fig. 3, the additional counterweight 40 is provided on the rear surface of the counterweight 30. The additional counterweight 40 is provided below the rear surface of the counterweight 30. This allows the center of gravity of the construction machine 1 to be lowered, thereby ensuring vehicle body stability.

[0029] As shown in Figures 3 and 5, the additional counterweight 40 has a housing 42 that forms the outer shell of the additional counterweight 40. The housing 42 houses the additional battery 60. The housing 42 may house the additional battery 60 instead of a heavy object that a normal additional counterweight has, or may house the additional battery 60 together with the heavy object that a normal additional counterweight has. In other words, the additional battery 60 is provided in the additional counterweight 40 and also functions as a heavy object that a normal additional counterweight has.

[0030] The housing 42 is long in the left-right direction and has a box shape that curves along the rear surface of the counterweight 30. The housing 42 is formed by a front plate 43 that faces forward, a rear plate 44 that faces rearward, an upper plate 45 that faces upward, a lower plate 46 that faces downward, a left plate 47 that faces leftward, and a right plate 48 that faces rightward. The left plate 47 and the right plate 48 constitute a pair of side plates 47, 48 that face in the left-right direction of the vehicle body.

[0031] 5 and 6, the housing 42 is provided with first mounting holes 42a for mounting the additional counterweight 40 to the counterweight 30. The first mounting holes 42a are provided at positions corresponding to the insert nuts 32 of the counterweight 30. The first mounting holes 42a are formed so as to penetrate the front plate 43 and the rear plate 44 of the housing 42 in the front-to-rear direction. The additional counterweight 40 is fixed by inserting multiple sets (for example, two sets) of bolts 37 and washers 38 into the first mounting holes 42a and tightening them into the insert nuts 32, as shown in FIG.

[0032] 5 and 6, the housing 42 is provided with second mounting holes 42b for mounting the counterweight 30 to the body frame 3a with the additional counterweight 40 attached. The second mounting holes 42b are provided at positions corresponding to the mounting holes 33 of the counterweight 30. The second mounting holes 42b are formed to penetrate the front panel 43 and the rear panel 44 of the housing 42 in the front-to-rear direction.

[0033] As shown in Fig. 5, a second connector 41 is provided on the front plate 43 of the housing 42. The second connector 41 is configured to be connectable to the first connector 31 of the counterweight 30 when the additional counterweight 40 is attached to the rear surface of the counterweight 30. As shown in Figs. 3 and 5, the second connector 41 has a front insertion port 41a and a rear insertion port 41b.

[0034] The front insertion port 41a of the second connector 41 is exposed from the front surface of the front plate 43, i.e., from the front surface of the additional counterweight 40. The front insertion port 41a of the second connector 41 is inserted into the rear insertion port 31b of the first connector 31 of the counterweight 30.

[0035] The rear socket 41b of the second connector 41 is exposed from the rear surface of the front panel 43, i.e., exposed inside the housing 42. A harness 62 extending from an additional battery 60 arranged inside the housing 42 is inserted into the rear socket 41b of the second connector 41.

[0036] The harness 62 extending from the additional battery 60 is inserted into the rear socket 41b of the second connector 41, which is then inserted into the rear socket 31b of the first connector 31, which has the cable 25 extending from the battery 20 inserted into its front socket 31a. This allows the additional battery 60 to be electrically connected to the battery 20 and to supply power to the battery 20.

[0037] Figure 7 is a diagram showing the details of the internal configuration of the additional counterweight 40 shown in Figure 3. Figure 8 is an enlarged view of the right part of the additional counterweight 40 shown in Figure 7. Figure 9 is a diagram showing the underside of the additional counterweight 40 shown in Figure 7.

[0038] An additional battery 60 is housed in the housing 42 of the additional counterweight 40. As shown in FIGS. 7 and 8, the multiple battery modules 61 of the additional battery 60 are arranged side by side in the left-right direction. The multiple battery modules 61 are arranged side by side in the left-right direction at positions that avoid the first mounting holes 42a and the second mounting holes 42b. The multiple battery modules 61 are arranged at intervals 49a in the left-right direction from each of the pair of side plates 47, 48 of the housing 42. The multiple battery modules 61 are arranged at intervals 49b from the top plate 45 of the housing 42. The multiple battery modules 61 are placed on and fixed to the bottom plate 46 of the housing 42.

[0039] 7, the housing 42 accommodates cooling fans 55, 56 that generate air flow inside the housing 42. The cooling fans 55, 56 include a first cooling fan 55 that draws air into the housing 42 from the outside, and a second cooling fan 56 that expels air from inside the housing 42 to the outside. The first cooling fan 55 is disposed in a gap 49a located between one of the pair of side plates 47, 48 (the left plate 47) and the additional battery 60. The second cooling fan 56 is disposed in a gap 49a located between the other of the pair of side plates 47, 48 (the right plate 48) and the additional battery 60.

[0040] The first cooling fan 55 and the second cooling fan 56 are each placed on and fixed to the bottom plate 46 of the housing 42. As shown in FIG. 9 , the bottom plate 46 of the housing 42 has vents 52 to 54 that allow air to circulate between the inside and outside of the housing 42. The vents 52 to 54 include an air inlet 52 disposed near the first cooling fan 55 (directly below the first cooling fan 55 in this embodiment) and an outlet 53 disposed near the second cooling fan 56 (directly below the second cooling fan 56 in this embodiment). Furthermore, the vents 52 to 54 include a through hole 54 that is different from the inlet 52 and the outlet 53. The through hole 54 also functions as an outlet for discharging water that has entered the housing 42.

[0041] 7 and 8, fan harnesses 57 extending from the first cooling fan 55 and the second cooling fan 56 pass through gaps 49a and 49b and extend toward a wiring hole 43a provided near the second connector 41 on the front panel 43 of the housing 42. The fan harnesses 57 exposed to the outside of the housing 42 from the wiring hole 43a extend forward and are connected to a low-voltage connector 26 connected to a low-voltage battery for electrical equipment (different from the high-voltage battery 20).

[0042] In this embodiment, the first cooling fan 55 and the intake port 52 are arranged on the left side of the housing 42, and the second cooling fan 56 and the exhaust port 53 are arranged on the right side of the housing 42, but these may be arranged in reverse.

[0043] As shown in FIGS. 7 and 8 , the housing 42 has ribs 50 extending inward in the left-right direction from the inner surface of each of the pair of side plates 47, 48. The ribs 50 are disposed in a gap 49a located between the pair of side plates 47, 48 and the additional battery 60. The ribs 50 have ventilation portions 51 that allow air to pass in the vertical direction. The ventilation portions 51 are formed, for example, by notches, holes, or chamfers formed in the ribs 50. The fan harness 57 may be disposed so as to pass through the ventilation portions 51.

[0044] Fig. 10 is a diagram illustrating an electrical connection structure of the plurality of battery modules 61 shown in Fig. 7. Fig. 11 is a diagram illustrating a mechanical connection structure of the plurality of battery modules 61 shown in Fig. 7.

[0045] As shown in Fig. 10, the plurality of battery modules 61 are electrically connected to each other by bus bars 64 between adjacent battery modules 61. The bus bars 64 are connected to external terminals of each battery module 61 that are electrically connected to the positive or negative electrodes by screws 63. The bus bars 64 are disposed above each battery module 61, spaced downward from the top plate 45 of the housing 42. A positive electrode harness 62 is connected to the positive electrode external terminal of the rightmost battery module 61 by the screws 63. A negative electrode harness 62 is connected to the negative electrode external terminal of the leftmost battery module 61 by the screws 63.

[0046] As shown in Fig. 8, the plurality of battery modules 61 connected to each other by bus bars 64 are sandwiched between a top plate 71 and a bottom plate 72 from above and below. The top plate 71 and the bottom plate 72 are fastened to each battery module 61 by fasteners 75. Adjacent battery modules 61 are separated by partition plates 73 extending in the above and below direction. This modularizes the plurality of battery modules 61.

[0047] 11, the battery module 61 has a long fastening hole 61a that penetrates in the vertical direction. The top plate 71 and the bottom plate 72 have fastening holes 71a and 72a that penetrate in the vertical direction, respectively. The fastening holes 61a, 71a, and 72a are formed at positions corresponding to each other so as to be aligned on the same straight line in the vertical direction.

[0048] As shown in FIG. 11 , the fastener 75 includes a weld nut 76, a collar 77, a long bolt 78, and a nut 79. The weld nut 76 is welded to the underside of the bottom plate 72 so as to cover the fastening hole 72a of the bottom plate 72 from below. The collar 77 is welded to the underside of the top plate 71 so as to cover the fastening hole 71a of the top plate 71 from below. The long bolt 78 is inserted into the fastening hole 71a of the top plate 71, the fastening hole 61a of the battery module 61, and the fastening hole 72a of the bottom plate 72, in that order. The lower end of the long bolt 78 protruding downward from the bottom plate 72 is screwed into the weld nut 76. A nut 79 is screwed onto the upper end of the long bolt 78 protruding upward from the top plate 71. In this way, the fastener 75 fastens the top plate 71 and the bottom plate 72 to the battery module 61.

[0049] Because weld nut 76 is welded to the underside of bottom plate 72, fastener 75 protrudes downward from bottom plate 72 and abuts against bottom plate 46 of housing 42. In other words, weld nut 76 also functions as a spacer, so that bottom plate 72 is positioned at a distance from bottom plate 46 of housing 42.

[0050] As described above, the construction machine 1 of this embodiment is an electric construction machine that includes the battery 20 mounted on the vehicle body, the front working mechanism 5 that is provided at the front of the vehicle body and driven using the battery 20 as a power source, and the counterweight 30 that is provided at the rear of the vehicle body. The construction machine 1 also includes an additional counterweight 40 that is detachably attached to the rear surface of the counterweight 30, and an additional battery 60 that supplies power to the battery 20. The additional battery 60 is provided on the additional counterweight 40.

[0051] This allows the construction machine 1 to increase the overall capacity of the batteries installed in the construction machine 1 without increasing the size of the battery 20 by increasing the number of battery modules 21 included in the battery 20. In particular, even if the construction machine 1 is a small hydraulic excavator, the construction machine 1 can easily increase the capacity of the batteries installed in it.

[0052] If the battery capacity installed in the construction machine 1 cannot be increased, the construction machine 1 may find itself in a situation where it cannot be moved from the work site if an unexpected event occurs during work, or the operator may have to work while constantly keeping an eye on the remaining battery charge, resulting in reduced work efficiency.However, since the battery capacity installed in the construction machine 1 can be easily increased, it is effective because it allows work to be carried out without encountering these situations.

[0053] When the construction machine 1 is a small hydraulic excavator, there are occasions when the machine will be used for indoor demolition work or industrial waste sorting, so there are significant benefits to the construction machine 1 being electric and not emitting exhaust fumes, and there are also significant benefits to having a large-capacity battery installed. Furthermore, when performing indoor demolition work or industrial waste sorting, a fork bucket is used as an attachment to the front working mechanism 5 instead of the bucket 8. In this case, the weight of the attachment itself is heavier than when the bucket 8 is used, so the construction machine 1 needs to be fitted with an additional counterweight 40 to ensure vehicle stability. Therefore, providing the additional battery 60 to the additional counterweight 40 makes it possible to easily and rationally increase the capacity of the installed battery, and is therefore particularly effective when the construction machine 1 is a small hydraulic excavator.

[0054] In a narrow work site where collisions with objects around the vehicle body are likely to occur, the construction machine 1 can work with the additional counterweight 40 (additional battery 60) removed. In cases where the work load on the hydraulic cylinders 9 to 11 is small and the working hours for one day can be covered by the charged power of the battery 20 alone, the construction machine 1 can work with the additional counterweight 40 (additional battery 60) removed.

[0055] In this way, by providing the additional battery 60 on the additional counterweight 40, the construction machine 1 can easily increase the capacity of the battery installed in the electric construction machine depending on the work site or the work content.

[0056] Furthermore, in the construction machine 1 of this embodiment, the counterweight 30 has a first connector 31 to which the cable 25 extending from the battery 20 is connected, and the additional counterweight 40 has a second connector 41 to which the harness 62 extending from the additional battery 60 is connected. The second connector 41 is configured to be connectable to the first connector 31 when the additional counterweight 40 is attached to the rear surface of the counterweight 30.

[0057] As a result, in the construction machine 1, simply by attaching the additional counterweight 40 to the rear surface of the counterweight 30, the second connector 41 can be connected to the first connector 31, and the additional battery 60 can be electrically connected to the battery 20. Therefore, the construction machine 1 can more easily increase the capacity of the battery to be installed depending on the work site or the work content.

[0058] Furthermore, in the construction machine 1 of this embodiment, the additional counterweight 40 has a housing 42 that houses the additional battery 60, and cooling fans 55, 56 that are housed in the housing 42 and generate air flow inside the housing 42. The housing 42 has vents 52 to 54 that allow air to circulate between the inside and outside of the housing 42.

[0059] This allows the construction machine 1 to cool the additional battery 60, thereby suppressing a rise in temperature of the additional battery 60. Therefore, the construction machine 1 can improve the thermal durability of the additional battery 60 and suppress breakdowns of the additional battery 60. Therefore, the construction machine 1 can easily increase the capacity of the battery installed depending on the work site or the work content, while ensuring the reliability of the installed battery.

[0060] Furthermore, in the construction machine 1 of this embodiment, the cooling fans 55, 56 include a first cooling fan 55 that draws air into the housing 42 from the outside, and a second cooling fan 56 that expels air from inside the housing 42 to the outside. The housing 42 has a pair of side plates 47, 48 that face in the left-right direction of the vehicle body. The additional battery 60 is disposed at a distance 49a from each of the pair of side plates 47, 48 in the left-right direction. The first cooling fan 55 is disposed in the distance 49a located between one of the pair of side plates 47, 48 and the additional battery 60. The second cooling fan 56 is disposed in the distance 49a located between the other of the pair of side plates 47, 48 and the additional battery 60.

[0061] As a result, the construction machine 1 can forcibly generate an air flow that crosses the additional battery 60 within the housing 42 of the additional counterweight 40. Therefore, the construction machine 1 can effectively cool the additional battery 60, and can further suppress a rise in temperature of the additional battery 60. Moreover, the construction machine 1 can position the additional battery 60 so as to avoid the left and right ends of the housing 42, which may collide during turning, and can therefore reduce impacts on the additional battery 60. In this way, the construction machine 1 can improve the thermal and mechanical durability of the additional battery 60, and can further suppress failures of the additional battery 60. Therefore, the construction machine 1 can easily increase the capacity of the battery to be installed, while further ensuring the reliability of the battery to be installed.

[0062] Furthermore, in the construction machine 1 of this embodiment, the housing 42 has ribs 50 that extend inward in the left-right direction from the inner surfaces of each of the pair of side plates 47, 48. The ribs 50 are disposed in spaces 49a that are located between each of the pair of side plates 47, 48 and the additional battery 60.

[0063] This allows the construction machine 1 to reduce impacts applied to both the left and right ends of the housing 42, thereby further reducing impacts applied to the additional battery 60. Therefore, the construction machine 1 can easily increase the capacity of the battery to be mounted, while further ensuring the reliability of the battery to be mounted.

[0064] Furthermore, in the construction machine 1 of this embodiment, the rib 50 has a ventilation portion 51 that allows air to pass through in the vertical direction.

[0065] This allows the construction machine 1 to prevent air flow from being obstructed by the ribs 50, further suppressing temperature rise in the additional battery 60. Therefore, the construction machine 1 can easily increase the capacity of the battery to be mounted, while further ensuring the reliability of the battery to be mounted.

[0066] Furthermore, in the construction machine 1 of this embodiment, the housing 42 has a lower plate 46 that faces downward. The lower plate 46 has, as the ventilation openings 52 to 54, an air intake opening 52 arranged near the first cooling fan 55.

[0067] This allows the construction machine 1 to reliably generate air flow inside the housing 42, further suppressing temperature rise in the additional battery 60. Therefore, the construction machine 1 can easily increase the capacity of the battery to be mounted, while further ensuring the reliability of the battery to be mounted.

[0068] Furthermore, in the construction machine 1 of this embodiment, the housing 42 has an upper plate 45 and a lower plate 46 that face in the vertical direction. The additional battery 60 has a plurality of battery modules 61 arranged side by side in the left-right direction, and a bus bar 64 that electrically connects the plurality of battery modules 61 to each other. The bus bar 64 is arranged above the plurality of battery modules 61, spaced apart from the upper plate 45 of the housing 42.

[0069] This makes it easier for the construction machine 1 to ensure the gap 49b between the upper plate 45 of the housing 42 and the additional battery 60. Therefore, the construction machine 1 can ensure space for arranging the harness 62 using this gap 49b, and the air flowing through this gap 49b can more effectively cool the bus bars 64, which tend to generate heat, and ultimately the additional battery 60. The construction machine 1 can further suppress temperature increases in the additional battery 60. Therefore, the construction machine 1 can easily increase the capacity of the battery installed, while further ensuring the reliability of the installed battery.

[0070] Furthermore, in the construction machine 1 of this embodiment, the additional battery 60 has a top plate 71 and a bottom plate 72 that sandwich from above and below the multiple battery modules 61 connected to each other by the bus bars 64, and fasteners 75 that fasten the top plate 71 and the bottom plate 72 to the battery modules 61. The fasteners 75 protrude downward from the bottom plate 72 and abut against the bottom plate 46 of the housing 42. The bottom plate 72 is disposed at a distance from the bottom plate 46 of the housing 42.

[0071] This makes it easier for the construction machine 1 to ensure a gap between the lower plate 46 of the housing 42 and the additional battery 60, and the air flowing through this gap can more effectively cool the additional battery 60. Therefore, the construction machine 1 can further suppress a rise in temperature of the additional battery 60. Therefore, the construction machine 1 can easily increase the capacity of the battery installed, while further ensuring the reliability of the installed battery.

[0072] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments and various modifications can be made without departing from the spirit of the present invention. In the present invention, elements of one embodiment can be added to elements of another embodiment, elements of one embodiment can be replaced with elements of another embodiment, or some of the elements of one embodiment can be deleted. [Explanation of symbols]

[0073] 1...construction machine, 2...undercarriage, 3...upper rotating body, 3a...body frame, 3b...fixing plate, 4...cab, 5...front work implement, 6...boom, 7...arm, 8...bucket, 9...boom cylinder, 10...arm cylinder, 11...bucket cylinder, 15...inverter, 16...electric motor, 20...battery, 21...battery module, 22...junction box, 23...service plug, 24...connector, 25...cable, 26...low voltage connector, 30...counterweight, 31...first connector, 31a...front socket, 31b...rear socket, 32...insert nut, 33...mounting hole, 35...bolt, 36...washer, 37...bolt, 38...washer, 40...additional counterweight, 41...second connector, 41a...front socket outlet, 41b...rear socket, 42...housing, 42a...first mounting hole, 42b...second mounting hole, 43...front plate, 43a...wiring hole, 44...rear plate, 45...upper plate, 46...lower plate, 47...left plate, 48...right plate, 49a...gap, 49b...gap, 50...rib, 51...vent, 52...intake port (vent), 53...outlet port (vent), 54...through hole (vent), 55...first cooling fan (cooling fan), 56...second cooling fan (cooling fan), 57...fan harness, 60...additional battery, 61...battery module, 61a...fastening hole, 62...harness, 63...screw, 64...bus bar, 71...top plate, 71a...fastening hole, 72...bottom plate, 72a...fastening hole, 73...partition plate, 75...fastener, 76...welding nut, 77...collar, 78...long bolt, 79...nut

Claims

1. A battery installed in the vehicle; a front working implement provided at a front portion of the vehicle body and driven by the battery as a power source; A counterweight provided at the rear of the vehicle body; An electric construction machine comprising: An additional counterweight detachably attached to the rear surface of the counterweight; an additional battery for supplying power to the battery; The additional battery is provided on the additional counterweight. A construction machine characterized by:

2. the counterweight has a first connector to which a cable extending from the battery is connected, the additional counterweight has a second connector to which a harness extending from the additional battery is connected, The second connector is configured to be connectable to the first connector in a state in which the additional counterweight is attached to the rear surface of the counterweight.

2. The construction machine according to claim 1 .

3. The additional counterweight has a housing that houses the additional battery, and a cooling fan that is housed in the housing and generates an air flow inside the housing, The housing has a vent hole for allowing air to circulate between the inside and the outside of the housing.

2. The construction machine according to claim 1 .

4. the cooling fan includes a first cooling fan that draws air into the housing from the outside, and a second cooling fan that expels air from inside the housing to the outside; The housing has a pair of side plates facing in the left-right direction of the vehicle body, the additional battery is disposed at a distance from each of the pair of side plates in the left-right direction, the first cooling fan is disposed in the space between one of the pair of side plates and the additional battery; The second cooling fan is disposed in the space between the other of the pair of side plates and the additional battery.

4. The construction machine according to claim 3.

5. the housing has a pair of side plates facing in a left-right direction of the vehicle body, and ribs extending inward from inner surfaces of each of the pair of side plates along the left-right direction, the additional battery is disposed at a distance from each of the pair of side plates in the left-right direction, The rib is disposed in the space between each of the pair of side plates and the additional battery.

4. The construction machine according to claim 3.

6. The rib has a ventilation portion that allows the air to pass in the vertical direction of the vehicle body.

6. The construction machine according to claim 5.

7. The additional counterweight has a housing that houses the additional battery, The housing has a lower plate facing downwardly of the vehicle body, The lower plate has a vent hole for allowing air to circulate between the inside and the outside of the housing.

2. The construction machine according to claim 1 .

8. The additional counterweight has a cooling fan that is housed in the housing and generates an air flow inside the housing, the cooling fan includes a first cooling fan that draws air into the housing from the outside, and a second cooling fan that expels air from inside the housing to the outside; The housing has a pair of side plates facing in the left-right direction of the vehicle body, the additional battery is disposed at a distance from each of the pair of side plates in the left-right direction, the first cooling fan is disposed in the space between one of the pair of side plates and the additional battery; the second cooling fan is disposed in the space between the other of the pair of side plates and the additional battery, The lower plate has, as the ventilation opening, an air intake port disposed near the first cooling fan and an air exhaust port disposed near the second cooling fan.

8. A construction machine according to claim 7.

9. The housing has an upper plate and a lower plate facing in the up-down direction of the vehicle body, the additional battery includes a plurality of battery modules arranged side by side in the left-right direction and a bus bar that electrically connects the plurality of battery modules to each other, The bus bar is disposed above the battery modules and spaced apart from the upper plate of the housing.

4. The construction machine according to claim 3.

10. the additional battery includes a top plate and a bottom plate that sandwich the plurality of battery modules connected to each other by the bus bars from the up-down direction, and fasteners that fasten the top plate and the bottom plate to the battery modules, the fastener protrudes downward from the bottom plate and abuts against the lower plate of the housing; The bottom plate is disposed apart from the lower plate of the housing.

10. The construction machine according to claim 9.

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