JP2014007871A - Working machine and method of controlling discharge of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working machine adapted to convert power of a secondary battery to motive power which suppresses the occurrence of an unintended device operation stop caused by voltage management of the secondary battery.SOLUTION: The working machine includes: a plurality of assembled batteries 18 each comprising a plurality of secondary batteries combined which are connected in parallel to a main circuit; and a switch 25 for selectively connecting/disconnecting each of the plurality of assembled batteries to/from the main circuit. The switch 25 selectively connects one of the plurality of assembled batteries 18 to the main circuit until an SOC of every one of the plurality of assembled batteries 18 reaches the same set value A1.

Description

  The present invention relates to a work machine that converts electric power of a secondary battery into power and a discharge control method thereof.

  Some working machines including construction machines such as hydraulic excavators and industrial machines such as forklifts include a secondary battery and convert the electric power of the secondary battery into power. As this type of work machine, for example, a battery-type hydraulic excavator (battery excavator) that includes a secondary battery and an electric motor instead of an engine, and that drives a hydraulic pump for driving a hydraulic actuator with the electric motor, There are a hybrid hydraulic excavator provided with a secondary battery and a generator motor, a wheel loader and a dump truck that drive an electric motor for traveling with electric power from a secondary battery.

  Some types of this type of work machine are configured to be able to supply power simultaneously from a plurality of secondary batteries connected in parallel from the viewpoint of securing a long operating time. Although the technical field is different from that of work machines, electronic devices that use multiple batteries as power sources (for example, laptop-type small computers) start using one battery, and then use the batteries sequentially. By switching and using, the battery is effectively consumed, and after using all the batteries, by connecting multiple batteries in parallel with an OR circuit, before the batteries are completely consumed In some cases, the backup of the internal backup batteries (emergency batteries other than the plurality of batteries described above) is reduced by performing a saving process of the data being executed and then stopping the apparatus (Japanese Patent Laid-Open No. Hei 8). -336243).

JP-A-8-336243

  The range of voltage that can be used for the secondary battery is determined from the viewpoint of preventing deterioration, and when the voltage falls below that range, the power supply by the secondary battery is controlled to be stopped. For example, the secondary battery includes a lithium ion battery, a lead storage battery, a nickel metal hydride battery, and the like. Among these, the lithium ion battery is said to require particularly strict voltage management.

  By the way, in a work machine, the magnitude and fluctuation of power consumption are extremely large as compared with an electronic device such as a small computer, and a steep voltage fluctuation occurs particularly in heavy work (for example, an operation of fully operating the operation lever). For this reason, in the work machine, there is a possibility that an unintended device stop may occur if heavy work is to be performed even though it is considered that power remains on the battery remaining amount display.

  The technology of the electronic device employs a configuration that switches to another battery for the first time when the voltage (reference voltage) drops to such an extent that it can be determined that it is difficult to continue further operation. When employed in a work machine, when heavy work requiring a large amount of power is required, the power required for the work cannot be output from the battery, and the work machine may stop operating.

  In addition, charging of work machines equipped with a plurality of assembled batteries tends to increase the charging time compared to electronic devices because the capacity of each assembled battery is large, but when the voltage of each assembled battery is different, Since it is necessary to charge each battery individually, there is a concern that the charging time will be further prolonged. In particular, in a working machine driven only by electricity (for example, a battery excavator that drives a hydraulic pump with an electric motor), extending the charging time is a problem that directly leads to a reduction in work efficiency, and a reduction in the charging time is eagerly desired. .

  Furthermore, the battery pack of the electronic device is inexpensive and lightweight and compact enough to be portable, so it can be easily replaced on a daily basis in terms of cost and work. Since batteries are heavy and huge, routine replacement work is impractical. Therefore, it is desired that the configuration is based on the premise that the battery is not replaced.

  An object of the present invention is to suppress the occurrence of unintended device operation stop caused by voltage management of a secondary battery in a work machine that converts the power of the secondary battery into power.

  (1) In order to achieve the above object, the present invention provides a plurality of assembled batteries obtained by combining a plurality of secondary batteries in a work machine including a secondary battery for supplying power to a main circuit. A plurality of assembled batteries respectively connected in parallel to the main circuit; and a switch for switching connection / disconnection to / from the main circuit for each of the plurality of assembled batteries, wherein the switch includes the plurality of assembled batteries. Until all of the SOCs reach the same set value, one of the plurality of assembled batteries is selectively connected to the main circuit.

  (2) In the above (1), preferably, when all of the SOCs of the plurality of assembled batteries have reached the set value, the switching unit may replace at least two of the plurality of assembled batteries with the main circuit. Shall be connected.

  (3) In the above (1) or (2), preferably, the set value is set to be equal to or greater than a value at which the required power can be output even when the required power from the power supply target device of the assembled battery is maximum. It shall be.

  (4) In any one of the above (1) to (3), preferably, when all the SOCs of the plurality of assembled batteries reach the same set value, a notification for notifying the operator that charging is required A device is further provided.

  (5) Moreover, in order to achieve the said objective, this invention is a discharge control method of the working machine provided with the some assembled battery which combines a some secondary battery, The power consumption of the electric power feeding object apparatus of the said assembled battery Until all the SOCs of the plurality of assembled batteries reach the same set value determined on the basis of the plurality of assembled batteries, and selectively connect one of the plurality of assembled batteries to a main circuit, After all the SOCs of the batteries reach the set value, all of the plurality of assembled batteries are connected in parallel to the main circuit.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the unintended apparatus operation stop resulting from the voltage management of a secondary battery can be suppressed.

1 is an external view of a battery-type hydraulic excavator according to an embodiment of the present invention. The block diagram of the electrical storage system mounted in the hydraulic shovel which concerns on embodiment of this invention. The figure which shows the display screen of the display apparatus which concerns on embodiment of this invention. The 1st flowchart of the discharge control process which concerns on embodiment of this invention. The 2nd flowchart of the discharge control process which concerns on embodiment of this invention. The 3rd flowchart of the discharge control process which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an external view of a battery-type hydraulic excavator (battery excavator) according to an embodiment of the present invention. The hydraulic excavator shown in this figure includes an articulated work device 1A having a boom 1a, an arm 1b, and a bucket 1c, and a vehicle body 1B having an upper swing body 1d and a lower traveling body 1e.

  The boom 1a is rotatably supported by the upper swing body 1d and is driven by a hydraulic cylinder (boom cylinder) 3a. The arm 1b is rotatably supported by the boom 1a and is driven by a hydraulic cylinder (arm cylinder) 3b. The bucket 1c is rotatably supported by the arm 1b and is driven by a hydraulic cylinder (bucket cylinder) 3c. The upper swing body 1d is swiveled by an electric motor (swing motor) (not shown), and the lower runner 1e is driven by left and right travel motors (hydraulic motors) 3e, 3f (not shown). The hydraulic cylinder 3a, the hydraulic cylinder 3b, the hydraulic cylinder 3c, and the travel motors 3e and 3f are driven by pressure oil pumped from the tank 9 by the hydraulic pump 6 (see FIG. 2).

  FIG. 2 is a configuration diagram of a power storage system mounted on the hydraulic excavator according to the embodiment of the present invention. The power storage system shown in this figure includes a main controller for controlling various devices related to a hydraulic excavator, including control of two assembled batteries 18A and 18B and connection / disconnection between the assembled batteries 18A and 18B and the main circuit. 12, a display device 14 for displaying the state of charge of the assembled batteries 18A and 18B, and a power control device (inverter device) for controlling the motor 17 while converting DC power from the assembled batteries 18A and 18B into AC power ) 16, a three-phase AC motor (electric motor) 17 that generates power by the electric power of the assembled batteries 18A and 18B, a hydraulic pump 6 driven by the motor 17, and the assembled batteries 18A and 18B connected to the main circuit. A connection switching device 19 is provided for switching to a desired one.

  The main control device 12 has, as a hardware configuration, an arithmetic processing unit (for example, CPU) 21 for executing various control programs including control described later, and a memory for storing various data including the control program. A device (for example, ROM, RAM) 22 and an input / output device 23 for inputting / outputting various data (not shown) are provided, and various processes relating to the hydraulic excavator are executed. For example, the main control device 12 performs control of the hydraulic pump 6 by control of the inverter device 16 and display control of the display device 14.

  The assembled batteries 18A and 18B supply power to the main circuit, and are formed by combining a plurality of secondary batteries (battery cells), respectively, and are connected to the power control device 16 that is a part of the main circuit. Each of them is connected in parallel. The two assembled batteries 18A and 18B shown in the figure are the same, and the type, number, connection mode, and the like of the battery cells included in each assembled battery 18A and 18B are the same. As the assembled batteries 18A and 18B, lithium ion batteries, lead storage batteries, nickel hydride batteries, and the like can be used.

  The two assembled batteries 18A and 18B are connected to the power control device 16 via a switch 25 that switches connection / disconnection to / from the main circuit for each assembled battery. In the example shown in the figure, two switches 25 a and 25 b are provided as the switch 25. The two switches 25a and 25b are respectively provided on power lines that connect the assembled batteries 18A and 18B and the power control device 16 in parallel. Each switch 25a, 25b connects the assembled batteries 18A, 18B to the main circuit when switched on, and disconnects the assembled batteries 18A, 18B from the main circuit when switched off. A control signal is input from the main controller 12 to each of the switches 25a and 25b, and the switches 25a and 25b are turned on / off based on the control signal.

  Voltage sensors 41a and 41b for measuring battery voltage and temperature sensors 42a and 42b for measuring battery temperature are attached to the assembled batteries 18A and 18B, respectively. Current sensors 43a and 43b for measuring the charge / discharge current values of the assembled batteries 18A and 18B are attached to the power lines connecting the switches 25a and 25b and the assembled batteries 18A and 18B. The voltage sensors 41a and 41b, the temperature sensors 42a and 42b, and the current sensors 43a and 43b are connected to the battery monitoring device 11.

  The battery monitoring device 11 calculates the state of charge (SOC), the degree of deterioration (SOC), and the like of each assembled battery 18A, 18B, and each assembled battery 18A, 18B is overcharged / overcharged. This is for monitoring whether or not the battery is discharged, and is connected to the assembled batteries 18A and 18B via the communication line 15. In addition, the measured values of the various sensors 41, 42, 43 are also input to the battery monitoring device 11 via the communication line 15. Information such as the SOC calculated by the battery monitoring device 11 is output to the main control device 12 via the communication line 13. The battery monitoring device 11 has, as a hardware configuration, an arithmetic processing device (for example, CPU) for executing various control programs, and a storage device (for example, ROM, RAM) for storing various data including the control program. Etc. (both not shown). The SOC of each assembled battery 18A, 18B is calculated by a known method.

  Here, the “charge rate” is calculated as a value indicating the SOC of each of the assembled batteries 18A and 18B. The charging rate can be defined as “100% −100 × discharge amount from current full charge / full charge capacity”. The “discharge amount” in the equation can be calculated by integrating current values measured by the current sensors 41a and 41b. As a method of calculating the initial value of the charging rate, a table (OCV table) in which the relationship between the SOC and the OCV (open voltage) relating to the assembled batteries 18A and 18B is defined, and the operation of the hydraulic excavator after a predetermined time has elapsed after charging. Some calculate the SOC based on the voltage (OCV) previously measured by the voltage sensors 41a and 41b. Further, the charging rate during operation of the hydraulic excavator may be calculated as “charging rate initial value + discharge amount / full charge capacity × 100”.

  In addition, since the full charge capacity of the battery is deteriorated as it is used, it is preferable that the battery monitoring apparatus 11 calculates and appropriately updates using a known method (for example, the technique described in JP-A-6-242193). . For example, the full charge capacity can be defined as “full charge capacity (Ah) = 100 × Q / | charge rate before operation−charge rate after operation | (Q: discharge amount during operation)”. Thereby, the charging rate before the operation of the hydraulic excavator is calculated using the OCV table, and the discharge amount Q during operation is separately calculated as an integral value of the output value (current value) of the ammeter 43a or the ammeter 43b. If the charge rate after completion is calculated using the OCV table, the full charge capacity can be calculated.

  The display device 14 is connected to the input / output device 23 of the main control device 12, and based on the input value from the main control device 12, the remaining capacity (SOC) and battery capacity of each assembled battery 18A, 18B is small. Display a warning.

  FIG. 3 is a diagram of a display screen of the display device 14 according to the embodiment of the present invention. As shown in this figure, on the screen of the display device 14, a remaining amount display unit 31 for displaying the SOC of each assembled battery 18A, 18B, and a message prompting the operator to charge the assembled batteries 18A, 18B Is displayed. “Battery 1” in the remaining amount display unit 31 refers to the assembled battery 18A, and “Battery 2” refers to the assembled battery 18B. Further, a mark (a circle mark in the example of FIG. 3) is attached to the battery pack currently in use (that is, the battery pack related to the switch 25 that is switched to ON). Note that the screen of FIG. 3 is a case where a warning display is displayed on the message display unit 32 in S106 in FIG. Needless to say, graphics may be used in place of characters and symbols when the remaining amount of each battery and the battery currently in use are displayed on the screen.

  Next, the discharge control process in the hydraulic excavator configured as described above will be described. FIG. 4 is a first flowchart of the discharge control process according to the embodiment of the present invention. First, it is assumed that the SOCs of the two assembled batteries 18A and 18B are the maximum and the assembled battery 18A is connected to the main circuit (that is, the switch 25a is turned on) as a premise for executing the processing according to the flowchart of FIG. The switch 25b is switched to OFF). At this time, when the process shown in FIG. 4 is started, the battery monitoring device 11 calculates the SOC of the assembled battery 18A (connected battery) by using the method described above (S101), and the SOC is set. It is determined whether or not the value is equal to or less than A1 (S102).

  The SOC set value A1 is used to avoid the occurrence of unintentional stoppage of the hydraulic excavator when the SOC of the battery pack is reduced. This is a value determined based on the required power of the motor 17). The set value A1 is the same value as the SOC that can supplement the maximum power consumption of the motor 17 (which may be a design value, but is preferably an actual measurement value required during actual operation of the hydraulic excavator) with the power from one assembled battery 18. Or it is preferable to set more. The set value A1 is preferably as close as possible to a value that can compensate for the maximum power consumption. The set value A1 according to the present embodiment is set to be equal to or greater than a value at which the required power can be output even when the required power from the motor 17 is maximum. In addition, when there are multiple power supply target devices, it is necessary to consider whether or not power may be supplied to the work machines at the same time while the work machine is in operation. A1 may be set according to the total of the maximum power consumption, and A1 may be set according to the maximum power consumption when power is not supplied at the same time.

  If it is determined in S102 that the SOC of the battery pack 18A is greater than A1, the process returns to S101 and the same processing as described above is repeated. On the other hand, when it is determined in S102 that the SOC is A1 or less, the battery monitoring device 11 calculates the SOC of all other assembled batteries (only the assembled battery 18B in the present embodiment) (S103). It is determined whether or not there is a calculated SOC that is greater than A1 (S104). That is, in the present embodiment, it is determined whether or not the SOC of the battery pack 18B is greater than A1.

  When S104 is reached for the first time after the start of the flowchart of FIG. 4 under the above-mentioned preconditions, the SOC of the battery pack 18B is 100%, which is larger than A1, and the process proceeds to S105. In S105, the main controller 12 outputs a signal for switching the switch 25b for the assembled battery 18B to ON while outputting a signal for switching the switch 25a for the assembled battery 18A to OFF. Thereby, the assembled battery 18A and the main circuit are disconnected, and the assembled battery 18B and the main circuit are connected. When the switching of the switch 25 is completed, the process returns to S101 and the subsequent processing is repeated. In this case, in S101, the SOC of the newly connected battery pack 18B is calculated.

  On the other hand, in S104, when there is no calculated SOC that is larger than A1 (that is, when the SOCs of the two assembled batteries 18A and 18B are both A1 or less), the main controller 12 determines that the battery “The charging rate has dropped. Please stop the work as soon as possible before charging.” A message indicating that the message display unit 32 (see FIG. 3) displays a message to the display device 14 (S106). Thus, a series of processing ends.

  According to the hydraulic excavator configured as described above, it is possible to prompt the operator to charge at the timing when the SOC of the assembled batteries 18A and 18B has decreased to the extent that the maximum power consumption of the motor 16 (power supply target device) cannot be covered. Therefore, it is possible to prevent the operation of the hydraulic excavator from suddenly stopping against the operator's intention. At that time, even if the operator requests an operation that maximizes the power consumption of the motor 16, the battery packs 18A and 18B have enough power to meet the operation request. For some time, the operation related to the operation request and the subsequent operation can be continued. Therefore, according to the present embodiment, it is possible to suppress the unintended stoppage of the hydraulic excavator caused by the voltage management of the secondary battery.

  FIG. 5 is a second flowchart of the discharge control process according to the embodiment of the present invention. Since the processing from S101 to S106 in the flowchart of this figure is the same as that shown in FIG. 4, the same reference numerals are used and description thereof is omitted. If a warning is displayed in S106, main controller 12 switches on switch 25a in addition to switch 25b. Thereby, the two assembled batteries 18A and 18B are connected in parallel (S107). As a result, the SOC can be doubled by a simple calculation as compared to before parallel connection.

  When the switching of the switch 25 is completed in S107, the battery monitoring device 11 calculates the SOC of one of the two assembled batteries 18A and 18B connected in parallel (S108), and the SOC is equal to or less than the set value A0. It is determined whether or not (S109). The set value A0 of the SOC is the minimum value of the SOC related to the use range of each of the assembled batteries 18A and 18B (that is, a value at which it is determined that it is difficult to continue the operation of the hydraulic excavator beyond that) and is a value smaller than A1. .

  If it is determined in S109 that the SOC of one of the two assembled batteries 18A and 18B, which is the SOC calculation target, is greater than A0, the process returns to S108 and the same processing is repeated. On the other hand, when it is determined in S109 that the SOC of the battery to be calculated is A0 or less, the main controller 12 outputs a signal for turning off the switches 25a and 25b, thereby supplying power from the assembled batteries 18A and 18B. Is stopped to stop the operation of the hydraulic excavator (S110).

  According to the excavator configured as described above, when the SOC of all the assembled batteries 18A, 18B reaches A1 or less, the assembled batteries 18A, 18B are connected in parallel. Compared to the case where one assembled battery is connected, the operation time can be increased by a factor of two by simple calculation. Therefore, according to the present embodiment, it is possible to suppress the unintended stoppage of the hydraulic excavator due to the voltage management of the secondary battery. In addition, although the case where there were two assembled batteries was demonstrated above, the number of assembled batteries may be three or more. In this case, if at least two of the three or more assembled batteries are connected in parallel in S107, at least the same effect as in the case of FIG. 4 can be obtained.

  By the way, when the voltages of the assembled batteries 18A and 18B are different, current flows from the assembled battery having a relatively high voltage to the assembled battery having a lower voltage when they are connected in parallel to the charging device. And the charging time tends to be longer. However, in this embodiment, after S107, the voltages of at least two assembled batteries are held at the same value. Therefore, since the assembled batteries having the same voltage can be charged at the same time, the charging time can be shortened as compared with the case where the two voltages are different.

  FIG. 6 is a third flowchart of the discharge control process according to the embodiment of the present invention. The processing from S101 to S106 in the flowchart of this figure is the same as that shown in FIG. If a warning is displayed in S106, the main controller 12 outputs a predetermined signal, thereby switching one switch to ON while switching the other switch to OFF. In the following description, it is assumed that the switch 25a is switched on and the switch 25b is switched off. Thereby, only the assembled battery 18A is connected to the main circuit (S121).

  When S121 ends, the battery monitoring device 11 calculates the SOC of the assembled battery 18A (connected battery) (S122). Then, the power control device 16 limits the maximum output of the assembled battery 18A (that is, the maximum output of the motor 17) based on the SOC value calculated in S122 (S123). That is, even if the operator requests an output that cannot be output with the SOC of the battery pack 18A at that time, the output of the battery pack 18A (that is, the output of the motor 17) is limited to a value that can be output with the SOC. I do. Further, the battery monitoring device 11 determines whether or not the SOC calculated in S122 is equal to or less than the set value A0 (S124). The set value A0 is the same as in FIG.

  If it is determined in S124 that the SOC of the battery pack 18A is greater than A0, the process returns to S122 and the same processing is repeated. On the other hand, when it is determined in S124 that the SOC is A0 or less, the battery monitoring device 11 calculates the SOC of all other assembled batteries (only the assembled battery 18B in the present embodiment) (S125). It is determined whether or not there is a calculated SOC that is greater than A0 (S126). That is, in the present embodiment, it is determined whether or not the SOC of the battery pack 18B is greater than A0.

  When S126 is reached for the first time after the start of the flowchart of FIG. 6 under the above preconditions, the SOC of the battery pack 18B is A1 and is inevitably larger than A0, so the process proceeds to S127. In S127, the main controller 12 outputs a signal for switching the switch 25b for the assembled battery 18B to ON while outputting a signal for switching the switch 25a for the assembled battery 18A to OFF. Thereby, the assembled battery 18A and the main circuit are disconnected, and the assembled battery 18B and the main circuit are connected. When the switching of the switch 25 is completed, the process returns to S122 and the subsequent processing is repeated. In this case, in S122, the SOC of the newly connected assembled battery 18B is calculated.

  On the other hand, in S126, when there is no calculated SOC that is larger than A0 (that is, when the SOCs of the two assembled batteries 18A and 18B are both A0 or less), the main controller 12 switches the switches 25a and 25b. Is turned off to stop the operation of the excavator (S128).

  The hydraulic excavator configured as described above can also prompt the operator to charge at the timing when the SOC of the assembled batteries 18A and 18B has decreased. Further, at the time of warning in S106, since the battery packs 18A and 18B have enough power necessary for the operation that maximizes the power consumption of the motor 16, the operation related to the operation request and the subsequent operation are performed for a certain period. Can continue. Therefore, according to the present embodiment, it is possible to suppress the unintended stoppage of the hydraulic excavator due to the voltage management of the secondary battery.

  In the above description, the embodiment of the hydraulic excavator has been described. However, other construction machines and work machines may be used as long as the power of the secondary battery is converted into power. In addition, the power supply target device of each assembled battery may be an electric actuator other than the motor 17 described above, or may be an electric machine or an electric appliance other than the electric actuator.

  In each of the above embodiments, the case where the number of assembled batteries is two has been described. However, the number of assembled batteries may be three or more. Further, in the above, the operator is informed through the display device 14 that the SOC of the battery pack is decreasing, but other notification devices that notify the same effect by a warning light or warning sound are used. Also good.

  Further, in each of the above embodiments, until the warning is displayed in S106, it is set so that the operator can switch to any of the assembled batteries 18A and 18B via the connection switching device 19. The assembled battery 18 connected to the circuit may be arbitrarily replaced. That is, the assembled battery connected to the main circuit may be appropriately switched until the SOC of all the assembled batteries reaches A1. In this case, the switching request by the switching device 19 may be processed as an interrupt request that has priority over the processing of S101 to S105.

  In the above description, the calculation of the SOC of each assembled battery and the comparison between the SOC and the set values A1 and A0 have been described as being performed by the battery monitoring device 11, but the sensors 41, 42, and 43 You may comprise so that the main control apparatus 12 may perform all the processes which concern on the flowchart of FIGS.

  Further, the present invention is not limited to the above-described embodiment, and includes various modifications within the scope not departing from the gist thereof. For example, the present invention is not limited to the one having all the configurations described in the above embodiment, and includes a configuration in which a part of the configuration is deleted. In addition, part of the configuration according to one embodiment can be added to or replaced with the configuration according to another embodiment.

  In addition, each of the configurations related to the control devices 11 and 12, functions and execution processes of the configurations, etc. are partly or entirely hardware (for example, logic for executing each function is designed by an integrated circuit). It may be realized with. The configuration related to the control devices 11 and 12 may be a program (software) that realizes each function related to the configuration of the control device by being read and executed by an arithmetic processing device (for example, a CPU). Information related to the program can be stored in, for example, a semiconductor memory (flash memory, SSD, etc.), a magnetic storage device (hard disk drive, etc.), a recording medium (magnetic disk, optical disc, etc.), and the like.

  In the above description of each embodiment, the control line and the information line are shown to be understood as necessary for the description of the embodiment, but all the control lines and information lines related to the product are not necessarily included. It does not always indicate. In practice, it can be considered that almost all the components are connected to each other.

  DESCRIPTION OF SYMBOLS 6 ... Hydraulic pump, 11 ... Battery monitoring device, 12 ... Main control device, 14 ... Display device, 16 ... Electric power control device, 17 ... Motor, 18 ... Battery assembly, 19 ... Battery switching device, 21 ... Arithmetic processing device, 22 DESCRIPTION OF SYMBOLS ... Memory | storage device, 23 ... Input / output processor, 25 ... Switch, 25a, 25b ... Switch, 31 ... Remaining amount display part, 32 ... Message display part, 41 ... Voltage sensor, 42 ... Temperature sensor, 43 ... Current sensor

Claims (5)

In a work machine including a secondary battery for supplying power to a main circuit,
A plurality of assembled batteries formed by combining a plurality of secondary batteries, each of the plurality of assembled batteries connected in parallel to the main circuit;
A switch for switching connection / disconnection to / from the main circuit for each of the plurality of assembled batteries,
The switch selectively connects one of the plurality of assembled batteries to the main circuit until all SOCs of the plurality of assembled batteries reach the same set value. Work machine. The work machine according to claim 1,
The switching machine connects at least two of the plurality of assembled batteries to the main circuit when all the SOCs of the plurality of assembled batteries reach the set value. In the work machine according to claim 1 or 2,
The work machine is characterized in that the set value is set to a value that can output the required power even when the required power from the power supply target device of the assembled battery is maximum. The work machine according to any one of claims 1 to 3,
A work machine further comprising a notification device for notifying an operator that charging is required when all SOCs of the plurality of assembled batteries have reached the same set value. In a discharge control method of a work machine including a plurality of assembled batteries formed by combining a plurality of secondary batteries,
Until all the SOCs of the plurality of assembled batteries reach the same set value determined based on power consumption of the power supply target device of the assembled battery, one of the plurality of assembled batteries is defined as a main circuit. Connect selectively,
After all the SOCs of the plurality of assembled batteries have reached the set value, all of the plurality of assembled batteries are connected in parallel to the main circuit.

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