Electric work machine

Abstract

Provided is an electric work machine comprising: an electric motor driven by electricity from an energy storage device; a state quantity detection device that detects a state quantity of the energy storage device; a display device; and a controller that controls displaying by the display device. The controller uses the state quantity of the energy storage device detected by the state quantity detection device as a basis for calculating a threshold value for an amount of energy stored in the energy storage device that would cause a shift to an output-limited state in which the output of the electric motor is limited, and causes the display device to display relative information indicating a relative relationship between the threshold value and a detected amount of energy stored, which is the amount of energy stored from out of the state quantity of the energy storage device detected by the state quantity detection device.

Description

electric work machine

[0001] The present invention relates to an electric work machine equipped with an electricity storage device and an electric motor that is driven by electric power from the electricity storage device.

[0002] A typical construction machine includes a power storage device such as a lithium-ion battery and an electric motor powered by the power storage device to drive a hydraulic pump. In such construction machines, the remaining charge of the power storage device is displayed to prevent over-discharge of the power storage device due to the operation of the hydraulic pump. When the remaining charge drops below a predetermined threshold, a warning is displayed to notify the operator. In such construction machines, the output of onboard equipment, such as the power storage device, may be limited depending on the load condition and operating environment, such as temperature. This state is hereinafter referred to as an "output limited state." Patent Document 1, for example, discloses a technology that displays the remaining charge of the power storage device and the available operating time based on the remaining charge. Patent Document 2, for example, discloses a technology that displays the output limited state (degree of speed reduction) based on the current available output voltage of the power storage device.

[0003] International Publication No. 2020 / 065994 Japanese Patent Application Laid-Open No. 2017-43923

[0004] It is known that such an output limited state can be caused by various factors other than the remaining charge of the power storage device, such as the operating environment (e.g., temperature) and the load state, etc. For this reason, it is difficult for an operator to grasp, based on the remaining charge alone, how much longer it will take to reach the output limited state, which makes it difficult to appropriately charge the power storage device.

[0005] The present invention has been made in consideration of the above points, and proposes an electric work machine that makes it easy for the operator to understand the relationship between the current remaining charge of the power storage device and the output limit state, and that is capable of appropriately charging the power storage device.

[0006] In order to solve this problem, the present invention provides an electric work machine that includes a power storage device, an electric motor driven by power from the power storage device, a state quantity detection device that detects a state quantity of the power storage device, a display device, and a controller that controls the display on the display device.The controller calculates a threshold value for the amount of stored power of the power storage device at which the electric motor is shifted to an output limited state in which the output of the electric motor is limited, based on the state quantity of the power storage device detected by the state quantity detection device, and causes the display device to display relative information that indicates the relative relationship between the threshold value and the detected amount of stored power, which is the amount of power stored among the state quantities of the power storage device detected by the state quantity detection device.

[0007] According to the present invention, an operator can easily grasp the relationship between the current remaining charge of the power storage device and the output limit state, and can appropriately charge the power storage device.

[0008] It is a side view showing an example of the appearance of the construction machine in this embodiment. It is a block diagram showing an example of the electrical configuration of the construction machine shown in Figure 1. It is a block diagram showing an example of the configuration of the display command value calculation unit shown in Figure 2. It is a diagram showing a first display example of the display device in this embodiment. It is a diagram showing a second display example of the display device in this embodiment.

[0009] An embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a side view showing an example of the appearance of a construction machine 1 as an example of an electric work machine in this embodiment. In this embodiment, an electric shovel will be used as an example of the construction machine 1, but the construction machine 1 may be any other type of construction machine. First, an overview of an example configuration of the construction machine 1 will be described.

[0010] The construction machine 1 mainly comprises a rotating body 3 that can be rotated by a rotating mechanism, and a traveling body 2. The construction machine 1 is also equipped with a power storage device (not shown). The traveling body 2 allows the construction machine 1 to travel by means of crawlers 5 driven by a traveling hydraulic motor 4.

[0011] The construction machine 1 includes an electric motor as an example of electrically powered equipment that operates using power from the power storage device. The electric motor will be described later.

[0012] The rotating body 3 mainly includes a cab 7 and a front device 6. An operator who operates the construction machine 1 rides in the cab 7. A display device, which will be described later, is provided in the cab 7. Note that this display device may be provided outside the cab 7 instead of inside it.

[0013] The front device 6 includes a boom 9, an arm 10, and a bucket 11. The boom 9 is driven by a hydraulic cylinder 8a. The arm 10 is driven by a hydraulic cylinder 8b. The bucket 11 is driven by a hydraulic cylinder 8c. This allows the construction machine 1 to perform work such as excavation.

[0014] Figure 2 is a block diagram showing an example of the electrical configuration of the construction machine 1 shown in Figure 1. The construction machine 1 is equipped with a power storage device 12, a rotation speed dial 19, a mode switch 20, a power storage device controller 17, an inverter 13, an electric motor 14, a hydraulic pump 15, a control valve 16, hydraulic cylinders 8a, 8b, and 8c, a swing hydraulic motor 21, a traveling hydraulic motor 4, a vehicle controller 18 as an example of a controller, and a display device 22. The power storage device 12 supplies power to the electric motor 14, the electric motor 14 drives the hydraulic pump 15, and the vehicle controller 18 controls the power supplied to the electric motor 14 and also controls the display on the display device 22. A specific description will be given below.

[0015] The rotation speed dial 19 is an operation unit for operating the rotation speed of the electric motor 14. The mode switch 20 is a switch for changing the operation mode of the electric motor 14. Based on an input signal from the rotation speed dial 19 and an input signal from the mode switch 20, the vehicle body controller 18 sets an output limit application range that indicates the range within which an output limit for the electric motor 14 relative to the amount of electricity stored in the electricity storage device 12 is applied.

[0016] The power storage device 12 is an example of a power storage device and is, for example, a secondary battery such as a lithium ion battery. The power storage device 12 supplies charged power to the inverter 13. The power storage device 12 may be another type of secondary battery.

[0017] The storage device controller 17 is an example of a state quantity detection device, which collects information from sensors installed inside the storage device 12, detects the amount of stored electricity and abnormalities in the storage device 12, and outputs various signals described below to the vehicle controller 18.

[0018] The inverter 13 converts the DC power supplied from the power storage device 12 into AC power and supplies it to an electric motor 14, which is an example of an electrically powered device, to drive the electric motor 14. In other words, the electric motor 14 is driven by the power of the power storage device 12. The electrically powered device may be an electrically powered device other than the electric motor 14.

[0019] The hydraulic pump 15 generates hydraulic pressure by being driven by the electric motor 14. The generated hydraulic pressure is distributed by a control valve 16 to the hydraulic cylinder 8a that drives the boom 9, the hydraulic cylinder 8b that drives the arm 10, the hydraulic cylinder 8c that drives the bucket 11, the traveling hydraulic motor 4 that drives the crawler 5, and the swing hydraulic motor 21 that drives the swing mechanism.

[0020] The vehicle controller 18 has a display command value calculation unit 18a and an abnormality determiner 18b, and signal lines are connected between each of the devices, namely the inverter 13, the electric motor 14, the hydraulic pump 15, the storage device controller 17, the rotation speed dial 19, the mode switch 20, and the display device 22.

[0021] The vehicle body controller 18 controls the power supplied to the electric motor 14. The vehicle body controller 18 calculates, for example, the remaining charge of the power storage device 12 as the amount of electricity stored in the power storage device 12. The vehicle body controller 18 calculates a threshold value for the remaining charge of the power storage device 12 at which the electric motor 14 should be shifted to an output limited state in which the output of the electric motor 14 is limited, based on, for example, at least one of the temperature state of the electric motor 14 and the load status of the electric motor 14. The vehicle body controller 18 calculates, from the amount of electricity stored in the power storage device 12 detected by the power storage device controller 17, a threshold value for the amount of electricity stored in the power storage device 12 at which the electric motor 14 should be shifted to an output limited state in which the output of the electric motor 14 is limited, and causes the display device 22 to display relative information indicating the relative relationship between the detected amount of electricity stored, which is the amount of electricity stored among the state quantities of the power storage device 12 detected by the power storage device controller 17, and the threshold value.

[0022] In this embodiment, the range of thresholds of the remaining charge amount that should cause the transition to the output limited state is also referred to as the "output limit application range." This output limit application range is not uniformly determined based only on the remaining charge amount, but can vary depending on, for example, the temperature state of the power storage device 12 and the load state of the electric motor 14. Therefore, in this embodiment, the output limit application range is used instead of the output limit application value that represents the threshold of the remaining charge amount.

[0023] The storage device controller 17 outputs to the vehicle controller 18 a storage device charging rate signal SG1, a storage device allowable output power signal SG2, a storage device temperature signal SG3, a storage device abnormality signal SG4, a charging prompt notification threshold SG10, and an over-discharge warning threshold SG11.

[0024] The vehicle body controller 18 outputs an electric motor power control signal SG8 to the inverter 13. The inverter 13 outputs an inverter abnormality signal SG7 to the vehicle body controller 18.

[0025] The electric motor 14 outputs an electric motor abnormality signal SG6 to the vehicle body controller 18. The hydraulic pump 15 outputs a hydraulic pump abnormality signal SG5 to the vehicle body controller 18. The rotation speed dial 19 outputs an electric motor requested rotation speed signal SG12 to the vehicle body controller 18. The mode switch 20 outputs an operation mode signal SG13 to the vehicle body controller 18.

[0026] The power storage device charging rate signal SG1 is a signal that notifies the vehicle body controller 18 of the current charging rate of the power storage device 12. The power storage device allowable output power signal SG2 is a signal that notifies the vehicle body controller 18 of the amount of power that can be output by the power storage device 12. The power storage device temperature signal SG3 is a signal that notifies the vehicle body controller 18 of current temperature information of the power storage device 12.

[0027] The power storage device abnormality signal SG4 is a signal that notifies the vehicle body controller 18 of an abnormality in the power storage device 12. The power storage device abnormality signal SG4 is set to "1" when an abnormality is detected, and is set to "0" when no abnormality is detected.

[0028] The hydraulic pump abnormality signal SG5 is a signal that notifies the vehicle body controller 18 of an abnormality in the hydraulic pump 15. The hydraulic pump abnormality signal SG5 is set to "1" when an abnormality is detected, and is set to "0" when no abnormality is detected.

[0029] The electric motor abnormality signal SG6 is a signal that notifies the vehicle body controller 18 of an abnormality in the electric motor 14. The electric motor abnormality signal SG6 is set to "1" when an abnormality is detected, and is set to "0" when no abnormality is detected.

[0030] The inverter abnormality signal SG7 is a signal that notifies the vehicle body controller 18 of an abnormality in the inverter 13. The inverter abnormality signal SG7 is set to "1" when an abnormality is detected, and is set to "0" when no abnormality is detected.

[0031] The electric motor power control signal SG8 is a signal that controls the power supplied to the inverter 13. The electric motor power control signal SG8 allows the operator to adjust the magnitude of the output power target value of the electric motor 14 in consideration of the type of work being performed by the construction machine 1, using the electric motor requested rotation speed signal SG12 input from the rotation speed dial 19 and the operation mode signal SG13 input from the mode switch 20.

[0032] The equipment abnormality signal SG9 is output as a determination value of the abnormality determiner 18b. When an abnormality is detected in one or more of the power storage device abnormality signal SG4, the hydraulic pump abnormality signal SG5, the electric motor abnormality signal SG6, and the inverter abnormality signal SG7, the equipment abnormality signal SG9 is set to "1", and when an abnormality is not detected, the equipment abnormality signal SG9 is set to "0".

[0033] The charge prompt notification threshold SG10 is a threshold used to determine whether to issue a warning to the operator that charging of the power storage device 12 is necessary. The over-discharge warning threshold SG11 is a threshold used to determine whether a state will occur in which the allowable output power of the power storage device 12 is limited so that the charge rate does not fall below a lower limit due to discharging of the power storage device 12. Note that, although the charge prompt notification threshold SG10 and the over-discharge warning threshold SG11 are assumed to be input signals from the power storage device controller 17 in FIG. 2 , they may instead be set within the vehicle body controller 18 rather than as input signals from the power storage device controller 17.

[0034] The remaining charge amount display command value SG31, the output limit application range display command value SG32, the charge prompt application range display command value SG33, and the start-up limit application range display command value SG34 are determined by the control of the display command value calculation unit 18a described later.

[0035] The vehicle body controller 18 displays relative information indicating the relative relationship between the current remaining charge amount (detected remaining charge amount) of the power storage device 12 and the threshold value of the remaining charge amount on the display device 22. Specifically, the following information is displayed.

[0036] Based on the remaining charge display command value SG31, the vehicle body controller 18 displays the remaining charge 22b on the display device 22. Furthermore, based on the remaining charge display command value SG31, the output limit application range display command value SG32, the charge prompt application range display command value SG33, and the start-up limit application range display command value SG34, the vehicle body controller 18 displays the remaining charge 22b and, as an example of relative information showing the relative relationship, an output limit application range showing the range in which an output limit for the electric motor 14 is applied, on the display device 22. It is desirable that the display of the remaining charge 22b and the display of the output limit application range be arranged in parallel or be distinguishable by color (or sound) so that the relative relationship between them can be easily recognized.

[0037] Fig. 3 is a block diagram showing an example of the configuration of the display command value calculation unit 18a shown in Fig. 2. The display command value calculation unit 18a includes a first display command value setting unit 31, an output limit application range calculation unit 32, a charge prompt application range calculation unit 33, a start-up limit application range calculation unit 34, and a second display command value setting unit 35. The display device 22, details of which will be described later, displays a remaining charge display unit that displays the remaining charge, and an output limit application range display unit that displays at least the output limit application range.

[0038] First display command value setting unit 31 determines the remaining charge to be displayed on the remaining charge display unit based on the input value of power storage device charging rate signal SG1, and sets remaining charge display command value SG31.

[0039] Here, the remaining charge display unit displays the charge rate from 0 to 100% as an example of the remaining charge of the power storage device 12, and sets a percentage value (corresponding to the charge rate) to be displayed as an example of the remaining charge. For example, if the current input value of the power storage device charge rate signal SG1 is 30%, the value of the remaining charge display command value SG31 is output as 30%. Regarding the setting of the remaining charge display command value SG31, the percentage of the display command value may be changed in consideration of the use of a limited depth of the charge rate in the actual charge / discharge control of the power storage device 12. That is, instead of simply displaying the charge rate from 0 to 100%, for example, if a charge rate of 5% is not desirable, the display may omit displaying charge rates below 5% and only display a charge rate range from 5 to 100%.

[0040] Based on input values ​​of at least a partial combination of the power storage device allowable output power signal SG2, the power storage device temperature signal SG3, the equipment abnormality signal SG9, the electric motor requested rotation speed signal SG12, and the operation mode signal SG13, the output limit application range calculation unit 32 determines an output limit application range upper end value SG21 that indicates the upper end value of the range of thresholds for the remaining charge amount that should put the electric motor 14 in an output limited state. The output limit application range upper end value SG21 is set to the largest output value among values ​​set by the following output limit determination method.

[0041] The first output limit determination method is based on the condition that the value of the equipment abnormality signal SG9 is "1" and any equipment of the construction machine 1 is in an abnormal state. If an abnormality occurs in the equipment, an output limit state is entered in which the operation of the electric motor 14 is limited to protect the equipment regardless of the remaining charge of the power storage device 12, and therefore 100% is set as the upper limit value SG21 of the output limit application range.

[0042] The second output limit determination method is based on the condition that the power storage device allowable output power signal SG2 is below a threshold value, where the threshold value is the output power target value of the electric motor 14, which is set based on the states of the electric motor required rotation speed signal SG12 and the operation mode signal SG13. When the condition of the second output limit determination method is satisfied, the amount of power supplied from the power storage device 12 to the inverter 13 becomes insufficient, which corresponds to an output limit state.

[0043] Here, the power storage device 12 has a characteristic that the allowable output power varies depending on the temperature state and the remaining charge amount. As an example of such a characteristic of the power storage device 12, the allowable output power of the power storage device 12 tends to decrease when its temperature is low, and therefore, the lower the remaining charge amount of the power storage device 12, the lower the allowable output power related to the output limited state is set compared to normal.

[0044] On the other hand, as another example of such a characteristic of the storage device 12, in order to protect the storage device 12 from further overheating due to heat generation when power is applied when its temperature is high, the higher the temperature of the storage device 12, the lower the allowable output power related to the output limit state is set compared to normal.

[0045] In this way, the value of power storage device allowable output power signal SG2 is set based on the current temperature state and remaining charge amount, taking into consideration the characteristics of power storage device 12. In other words, the value of output limit application range upper limit value SG21 set by the second output limit determination method is set to any value between 0% and 100% depending on the state of each input signal to output limit application range calculation unit 32. Note that the above-mentioned application conditions are merely examples, and actual application conditions are not limited to these.

[0046] The charge reminder application range calculation unit 33 sets the upper limit value SG22 of the charge reminder application range based on the input value of the charge reminder notification threshold value SG10. The charge reminder only needs to be displayed when the remaining charge falls below a preset value. Therefore, the upper limit value SG22 of the charge reminder application range is set to, for example, 20% of the remaining charge after a long period of work, relative to 100% being the full charge rate. The value of SG22 may be changed taking into account the capacity of the power storage device 12, the work plan for the construction machinery, etc.

[0047] The start-up restriction application range calculation unit 34 sets the start-up restriction application range upper limit value SG23 based on the input value of the over-discharge warning threshold value SG11. To prevent the remaining charge of the power storage device 12 from falling below 0%, control is applied to restrict the start-up of the power storage device 12 when the remaining charge falls below a preset value. For example, the value of the start-up restriction application range upper limit value SG23 is set to 5%. Alternatively, if the operator determines that notification based on the charge reminder application range is sufficient, or if display of the start-up restriction range is not necessary, the start-up restriction application range upper limit value SG23 may be set to 0%.

[0048] The second display command value setting unit 35 receives as input the output limit application range upper end value SG21, the charge prompt application range upper end value SG22, and the startup limit application range upper end value SG23 calculated by the output limit application range calculation unit 32, the charge prompt application range calculation unit 33, and the startup limit application range calculation unit 34, respectively, and determines the output limit application range display command value SG32, the charge prompt application range display command value SG33, and the startup limit application range display command value SG34 to be displayed in the output limit application range display unit.

[0049] In this embodiment, taking into consideration the degree of impact on the operation of the construction machine 1, the display priority in the output limit application range display section is, in descending order, the start-up limit application range display command value SG34, the charge prompt application range display command value SG33, and the output limit application range display command value SG32.

[0050] The output limit application range display command value SG32, the charge prompt application range display command value SG33, and the start-up limit application range display command value SG34 are set so that the display of a low priority application range does not overlap with a high priority application range.

[0051] As a first display example, assume that the value of the output limit application range upper limit value SG21 is 0%, the value of the charge prompt application range upper limit value SG22 is 20%, and the value of the startup limit application range upper limit value SG23 is 0%. In this case, because the startup limit application range upper limit value SG23 is 0%, the startup limit application range display command value SG34 is set to no range display. Next, because the value of the charge prompt application range upper limit value SG22 is 20%, the value of the charge prompt application range display command value SG33 is set to a range display command of 0% to 20%. Then, because the output limit application range upper limit value SG21 is 0%, the output limit application range display command value SG32 is set to no range.

[0052] As a second display example, assume that the output limit application range upper limit value SG21 is 50%, the value of SG22 is 20%, and the value of the startup limit application range upper limit value SG23 is 5%. In this case, because the startup limit application range upper limit value SG23 is 5%, the startup limit application range display command value SG34 is set to 0% to 5%. Next, because the charge prompt application range upper limit value SG22 is 20%, the charge prompt application range display command value SG33 is set to a range display command of 5% to 20%, which is adjusted so as not to overlap with the display range of the startup limit application range display command value SG34. Then, because the output limit application range upper limit value SG21 is 50%, the output limit application range display command value SG32 is set to a range display command of 20% to 50%, which is adjusted so as not to overlap with the display ranges of SG34 and SG33.

[0053] FIG. 4 is a diagram showing a first display example of the display device 22, and FIG. 5 is a diagram showing a second display example of the display device 22. As shown in FIG.

[0054] The relative information described above includes a remaining charge display section 22a as an example of a first display section that indicates the ratio of a remaining charge 22b, which is an example of a detected amount of charge, to the full charge amount of the power storage device 12, and an output limit application range display section 22c as an example of a second display section that indicates the ratio of the threshold value to the full charge amount of the power storage device 12. The remaining charge display section 22a and the output limit application range display section 22c are displayed on the same scale on the display device 22. Note that the relative information indicating the relationship is not limited to a display such as the output limit application range 22d shown in the figure, and may be, for example, a visible mark such as an arrow or a dot, or a bar-shaped display object.

[0055] More specifically, the vehicle body controller 18 displays, on the display device 22, as the above-mentioned relative information, on the same scale: the current remaining charge 22b of the storage device 12 in the remaining charge display section 22a, which displays the remaining charge 22b as an example of the relative storage amount of the storage device to the fully charged amount of the storage device 12; and information indicating the relative relationship of the threshold value of the remaining charge 22b of the storage device 12 to the fully charged amount of the storage device 12 in the output limit application range display section 22c, which displays information (output limit application range 22d) indicating the relative relationship of the threshold value of the remaining charge 22b of the storage device 12 to the fully charged amount of the storage device 12. Here, the same scale means that the rate of increase / decrease of the remaining charge 22b in the remaining charge display section 22a (for example, a scale of 0 to 100%) and the rate of increase / decrease of the information indicating the relative relationship of the threshold value of the remaining charge 22b in the output limit application range display section 22c (for example, a scale of 0 to 100%) are displayed in parallel, making it easy to compare the magnitude relationship between the two (for example, a percentage scale).

[0056] That is, the display device 22 has, for example, a remaining charge display section 22 a and an output limit application range display section 22 c as display areas, and each display section is displayed, for example, on the same scale as described above. Here, the vehicle body controller 18 displays the remaining charge display section 22 a and the output limit application range display section 22 c as indicators.

[0057] In this embodiment, the remaining charge display section 22a and the output limit application range display section 22c are displayed side by side on the display device 22.

[0058] The remaining charge display section 22a displays a remaining charge 22b in accordance with the remaining charge display command value SG31 input from the display command value calculation section 18a.

[0059] The output limit application range display unit 22c displays the output limit application range 22d, the charge prompt application range 22e, and the startup limit application range 22f according to the values ​​of the output limit application range display command value SG32, the charge prompt application range display command value SG33, and the startup limit application range display command value SG34 input from the display command value calculation unit 18a.

[0060] The output restriction state can change according to the input signal of the vehicle body controller 18, and the vehicle body controller 18 changes information indicating the relative relationship of the remaining charge threshold according to the input signal of the vehicle body controller 18 and displays it on the display device 22.

[0061] In the illustrated example, if the output limit application range 22d includes the current remaining charge 22b displayed in the remaining charge display section 22a, for example in the vertical direction, the operator can easily understand that the electric motor 14 may be in an output limited state in the current state.

[0062] FIG. 4 is a diagram showing the state of the display device 22 in the case where the first display example in FIG. 3 is assumed.

[0063] The vehicle body controller 18 displays at least one threshold range as a threshold (range) for which a transition to the output limit state can be made in the output limit application range display section 22c on the display device 22. An example of the one threshold range is the output limit application range 22d.

[0064] In this case, the remaining charge 22b is set to 30%, the charge prompt application range 22e is set to 0% to 20%, and the operator can read that he or she can operate the construction machine 1 without any restrictions.

[0065] FIG. 5 is a diagram showing the state of the display device 22 in the case where the second display example in FIG. 3 is assumed.

[0066] The start restriction application range 22f indicates, for example, a range of the remaining charge indicating that the remaining charge of the power storage device 12 has decreased to a level that requires restricting the start of the electric motor 14. The charge prompt application range 22e indicates, for example, a range of the remaining charge indicating that the remaining charge of the electric motor 14 has decreased to a predetermined lower limit and the power storage device 12 should be charged. The output restriction application range 22d indicates, for example, a range of the remaining charge that may result in the output restriction state of the electric motor 14 described above.

[0067] In this case, the remaining charge amount 22b is set to 30%, the start-up restriction application range 22f is set to 0% to 5%, the charge prompt application range 22e is set to 5% to 20%, and the output restriction application range 22d is set to 20% to 50%. The operator can read that the output restriction is being applied for a reason other than a decrease in the remaining charge amount of the power storage device 12.

[0068] In this way, by reading the remaining charge display section 22a and the output limit application range display section 22c displayed on the display device 22 in combination, the operator can understand the relationship between the current remaining charge and the operational limit state of the construction machine 1.

[0069] The construction machine 1 according to this embodiment includes a power storage device 12, an electric motor 14 as an example of an electrically powered device driven by power from the power storage device 12, a power storage device controller 17 as an example of a state quantity detection device that detects a state quantity of the power storage device 12, a display device 22, and a vehicle controller 18 that controls the display of the display device 22. The vehicle controller 18 calculates a threshold value for the amount of stored power of the power storage device 12 at which the electric motor 14 is shifted to an output limited state that limits the output of the electric motor 14, based on the state quantity of the power storage device 12 detected by the charging device controller 17, and causes the display device 22 to display relative information that indicates the relative relationship between the detected amount of stored power, which is the amount of stored power among the state quantities of the power storage device 12 detected by the power storage device controller 17, and the threshold value.

[0070] Although it is difficult for an operator to determine whether the electric motor 14 may be in an output limited state based on the remaining charge 22b alone, the above-described configuration allows the operator to easily grasp the relative relationship between the current remaining charge of the power storage device 12 and the output limited state of the electric motor 14 by accessing the relative information. This allows the operator to appropriately charge the power storage device 12.

[0071] In the present embodiment, the relative information includes a remaining charge display section 22a as an example of a first display section that indicates the ratio of the remaining charge 22b, which is an example of the detected amount of charge, to the full charge amount of the power storage device 12, and an output limit application range display section 22c as an example of a second display section that indicates the ratio of the threshold to the full charge amount of the power storage device 12, and the remaining charge display section 22a and the output limit application range display section 22c are displayed on the same scale on the display device 22. In this way, because both are displayed on the same scale, the operator can easily visually recognize the relative information that indicates the relative relationship between the current remaining charge 22b of the power storage device 12 and the threshold for the remaining charge 22b, and can accurately grasp whether the electric motor 14 will be in an output limited state.

[0072] In this embodiment, the remaining charge display section 22a and the output limit application range display section 22c are displayed side by side on the display device 22. In this way, since the two are displayed side by side, the operator can easily visually recognize the relative information described above and can accurately grasp whether the electric motor 14 will be in an output limited state.

[0073] In this embodiment, the remaining charge display section 22a and the output limit application range display section 22c are displayed by indicators.

[0074] The construction machine 1 according to this embodiment further includes a rotation speed dial 19 for controlling the rotation speed of the electric motor 14, which is an example of electrically powered equipment, and a mode switch 20 for switching the operating mode of the electric motor 14, and the vehicle controller 18 sets the output limit application range, which indicates the range within which an output limit for the electric motor 14 is applied relative to the amount of electricity stored in the electricity storage device 12, based on an input signal from the rotation speed dial 19 and an input signal from the mode switch 20. For example, when the operator intentionally reduces the output of the construction machine 1 by operating the rotation speed dial 19, the mode switch 20, etc., the amount of power required by the electric motor 14 becomes lower than before operating the rotation speed dial 19, the mode switch 20, etc. Here, the greater the amount of power consumed by the electric motor 14, etc., the shorter the time it takes to reach a predetermined level of charge from the current level of charge. Therefore, by setting the output limit application range according to the current level of power required (= the input signal operated by the operator) when the amount of power required by the electric motor 14 is low and when it is high, it is possible to provide a certain period of grace time (for charging) for the storage device 12 before the construction machine 1 becomes completely unable to operate (when the current level of charge reaches the predetermined level of charge).

[0075] The present invention is not limited to the above-described embodiments, and includes various modifications and equivalent configurations within the spirit and scope of the appended claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, the elements described in parallel in the present embodiment may be configured such that at least one of the elements is connected in series to the other elements.

[0076] In the above embodiment, the display shapes of the remaining charge display section 22a and the output limit application range display section 22c shown in Figures 4 and 5 are not limited to the shapes shown as examples, as long as they are shapes that display the output limit application range in conjunction with the remaining charge 22b.

[0077] The present invention can be applied to, for example, an electric work machine equipped with a power storage device and an electric motor driven by electric power from the power storage device.

[0078] 1...construction machine, 2...traveling body, 3...swivel body, 4...traveling hydraulic motor, 5...crawler, 6...front device, 7...cab, 8a, 8b, 8c...hydraulic cylinder, 9...boom, 10...arm, 11...bucket, 12...electric storage device, 13...inverter, 14...electric motor, 15...hydraulic pump, 16...control valve, 17...electric storage device controller, 18...vehicle controller, 18a...display command value calculation unit, 18b...abnormality determiner, 19...rotation speed dial, 20...mode switch, 21...swing hydraulic motor, 22...display device, 22a...remaining charge display unit, 22b...remaining charge, 22c...output limit application range display unit, 22d...output limit application range, 22e...charge alert application range, 22f...startup limit application range, 31...remaining charge calculation unit, 32...output limit application range calculation unit, 33...charging Stimulation application range calculation unit, 34... Start-up restriction application range calculation unit, 35... Second display command value setting unit, SG1... Power storage device charging rate signal, SG2... Power storage device allowable output power signal, SG3... Power storage device temperature signal, SG4... Power storage device abnormality signal, SG5... Hydraulic pump abnormality signal, SG6... Electric motor abnormality signal, SG7... Inverter abnormality signal, SG8... Electric motor power control signal, SG9... Equipment abnormality signal, SG10... Charging Power alert notification threshold, SG11...over-discharge warning threshold, SG12...electric motor required rotation speed signal, SG13...operation mode signal, SG21...output limit application range upper limit value, SG22...charge alert application range upper limit value, SG23...startup limit application range upper limit value, SG31...remaining charge display command value, SG32...output limit application range display command value, SG33...charge alert application range display command value, SG34...startup limit application range display command value

Claims

1. An electrically driven working machine comprising: a power storage device; an electric motor driven by electric power from the power storage device; a state quantity detection device that detects a state quantity of the power storage device; a display device; and a controller that controls display on the display device, wherein the controller calculates a threshold value for the amount of stored power of the power storage device at which the electric motor will transition to an output limited state that limits output, based on the state quantity of the power storage device detected by the state quantity detection device, and causes the display device to display relative information that indicates the relative relationship between the threshold value and the detected amount of stored power, which is the amount of power stored among the state quantities of the power storage device detected by the state quantity detection device.

2. The electric working machine according to claim 1, characterized in that the relative information has a first display unit that shows the ratio of the detected amount of stored power to the fully charged amount of the storage device, and a second display unit that shows the ratio of the threshold value to the fully charged amount of the storage device, and the first display unit and the second display unit are displayed on the display device using the same scale.

3. The electric working machine according to claim 2, characterized in that the first display section and the second display section are displayed side by side on the display device.

4. The electric working machine according to claim 2, characterized in that the first display section and the second display section are displayed by indicators.

5. The electric working machine according to claim 1, further comprising: a rotation speed dial for controlling the rotation speed of the electric motor; and a mode switch for switching the operation mode of the electric motor, wherein the controller sets an output limit application range indicating the range within which the output limit of the electric motor is applied relative to the amount of electricity stored in the electricity storage device, based on an input signal from the rotation speed dial and an input signal from the mode switch.

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